text:
\section{Introduction}

The recently launched Herschel Space Observatory has provided astronomers with a spectacular and promising glimpse of the submillimeter universe \cite{Pilbratt}. For the next generation submillimeter instruments operating from space \cite{Nakagawa} or from ground-based facilities \cite{{Guesten},{Sebring}}, the improvement of performance generally implies to have better detector sensitivities and larger fields of view.
Another important point is the ability to fully cover the region between far-infrared and millimeter (typically between 50 $\mu$m and 2 mm). This means that the spectral response of the detector has to be optimum in the considered spectral window.

Bolometers are the detectors of choice for direct detection in this part of the spectrum. To get a high absorption efficiency, modern bolometer arrays generally use quarter wave cavities to absorb the incoming radiation from the telescope. They are therefore restricted, by design, to work in a specific spectral window. It is not a straightforward process to modify  the spectral range of operation of this type of detectors once assembled, because their cavities are usually made by spacers, etched materials or mechanical handling systems. However, when groups provide detectors to a project, many models are produced and only the ones with the perfectly matching parameters are selected for the mission. But some non-selected detectors can potentially give good performances in other bands, if their spectral response is enhanced. We have studied   a technical solution which is simple, fast to assemble and not expensive, that enables a detector originally designed for a single band to work in other spectral windows. The solution is based on an anti-reflecting (AR) layer whose optimum parameters are obtained by modeling.

This paper first describes the model used to obtain the spectral response:  a 2D analytic method which is fast, easy to implement  and more flexible than heavy 3D electromagnetic software.  Then the method is applied to the particular case of Herschel PACS bolometers.  Our group has developed these semiconductor sensors for the PACS photometer  \cite{{Poglitsch},{Billot06}}. These bolometers are optimized for the 60 $\mu$m - 210 $\mu$m band, but their spectral response decreases toward longer wavelengths (see next section).  With the new method described in the paper, we have found that simple configurations  with AR layers enable the PACS detectors to operate at longer wavelengths  (bands beyond 300 $\mu$m).  We focused our development on the 450 $\mu$m atmospheric window which is accessible from ground-based telescopes and which is of particular interest for astrophysical science. The results of simulation are compared to spectrometer measurements for validation in section 3.

\section{Modeling the Bolometer Spectral Response}

\subsection{Absorption principle of bolometers with $\lambda/4$ cavities. Case of the PACS bolometers}

Bolometer camera instruments for far-infrared to millimeter astronomy traditionally use integrating cavities and circular-aperture feedhorns  to couple  the detector to the telescope beam \cite{Richards94}. Generally, $2F\lambda$ or $1F\lambda$ horns were used to populate the focal planes of submillimeter bolometer cameras, with the disadvantage of undersampling the image. This is the main reason why many submillimeter cameras now use arrays of $0.5F\lambda$  bare detectors that instantaneously fully sample the image \cite{Griffin02}, and in most of the cases, the absorption is made by using $\lambda/4$ cavities.

We now take the example of the Herschel PACS detectors to describe the general behaviour of bolometers with such cavities. The bolometers that we have developed for Herschel were the first ones to use this cartesian architecture for far-infrared / submillimeter astronomy (see  Fig. \ref{Figure1}, \cite{Agnese99}). The principle of wave absorption is based on the Dennison-Hadley interference filters \cite{Hadley47}, sometimes called Salisbury screens \cite{{Salisbury},{Fante88}}. This consists in a reflecting metal layer placed at the bottom of a cavity (backshort), normal to the plane of propagation of the wave. In such a device, because of interferences between the incident and the 180$^{\circ}$  phase shifted reflected waves, a standing wave develops with a minimum of electric field intensity at the backshort and a maximum at a distance $\lambda/4$ above it. If an absorber is placed there (typically a resistive layer with a square resistance equal to the impedance of free space), 100$\%$ of the energy at this wavelength $\lambda$ can be absorbed. This absorbed incident power is converted to thermal energy and a thermometer measures the temperature rise.

For PACS, we use a semiconducting thermometer (phosphorous doped silicon, compensated with boron impurities, \cite{Zhang93}) located at the center of an etched silicon membrane, working at cryogenic temperature (300 mK). The silicon film is patterned as a thin grid in order to reduce the heat capacity  and the cross-section to cosmic rays \cite{Bock95}. A very thin layer of absorber is deposited on the supporting silicon grid and  absorbs the incoming submillimeter radiation (see Fig. \ref{Figure2}). This is not a uniform film, but a periodic resonant structure made of square loops, to improve the spectral response in a certain optical band (see next section for the details). The vacuum quarter-wave cavity is obtained by  indium bumps hybridization techniques. These spacers have three distinct roles: (i) define the cavity height, (ii) make a thermal link between the silicon detection layer and the substrate which is kept at a constant temperature, (iii) conduct the electrical signals between the thermometer and the cold-stage electronics which is located near the reflector. In PACS, the indium bumps are 20 $\mu$m thick. This enables us to cover the region between 60 $\mu$m and 210 $\mu$m with two distinct focal planes and three different optical filters \cite{Poglitsch}. Ideally, the detection of longer wavelengths should be possible by increasing the size of the indium bumps, but re-hybridization with larger structures is not a straightforward process.

From Fig. \ref{Figure2}b it should be noted that the grid does not extend over the entire pixel surface (fill factor $= 85\%$). Mirotznik et al. \cite{Mirotznik} have studied the influence of the area fill factor on the absorption for infrared detectors using $\lambda/4$ cavities. They showed that because of diffraction effects on the sides of the absorbing surface, the absorption can be improved by a factor up to 3 compared to the purely geometric estimate. We applied this principle to longer wavelengths and found that for PACS pixels (750 $\mu$m pixel pitch) at 150 $\mu$m, the correction factor is 1.1 (corresponds to a pixel pitch of 50 $\mu$m at a wavelength of 10 $\mu$m in Fig. 3 in \cite{Mirotznik}).

\subsection{Characteristic matrix method}

The model used to compute the spectral response of the bolometers is based on the method of characteristic matrix. This method was first described by Abel\`es \cite{Abeles}, and is now widely used in the thin film domain thanks to its ability to be rapidly  solved by common programming languages.  Considering a thin dielectric layer of thickness $d_1$ and refraction index $n_1$, it is possible to build a $2\times2$ matrix that links the electric fields of the two interfaces $a$ and $b$ of the film, see Fig. \ref{Figure3}.

For one layer, the relation is  (from \cite{Macleod})

\begin{equation}
\left(
\begin{array}{c}
  E_{a}   \\
  H_{a}
\end{array}
\right)=
\left(
\begin{array}{cc}
\cos\beta_1 & (i\sin\beta_1)/\eta_1\\
i\eta_1 \sin\beta_1 & \cos\beta_1
\end{array}
\right)
\left(
\begin{array}{c}
E_b\\
H_b
\end{array}
\right)
\label{matabeles}
\end{equation}
where $E_a$ is the total electric field at the first interface (sum of incident and reflected fields), $H_a$ is the total magnetic field at this same boundary. $E_b$ and $H_b$ are respectively the total electric field and magnetic field at interface $b$. The optical admittance of the medium is defined by $\eta_1=n_1\eta_0 cos\theta_0$ for TE modes and  $\eta_1=n_1\eta_0 / cos\theta_0$ for TM modes. $\eta_0=1/Z_0=1/377\Omega$  is the free space admittance and $\theta_0$ is the incident angle on the first layer. The phase shift $\beta_1$ due to the propagation through the medium  is

\begin{equation}
\beta_1=\frac{2\pi n_1d_1\cos\theta_0}{\lambda}
\end{equation}
where $\lambda$ is the wavelength in vacuum. The optical admittance is also defined by the general form
\begin{equation}
\eta=\frac{H}{E}
\label{admittance}
\end{equation}
The equation (\ref{matabeles}) transforms into

\begin{equation}
\left(
\begin{array}{c}
  E_{a}/E_b   \\
  H_{a}/E_b
\end{array}
\right)=
\left(
\begin{array}{c}
M\\
\end{array}
\right)
\left(
\begin{array}{c}
1\\
\eta_s
\end{array}
\right)
\label{matabeles2}
\end{equation}
where  $\left(M\right)$ is the characteristic matrix of the  layer \textit{m} and $\eta_s$ is the admittance of the exit medium (substrate). Defining $B= E_{a}/E_b$ and $C=H_{a}/E_b$, then for a stack of $q$ layers, Eq. (\ref{matabeles2}) becomes

\begin{equation}
\left(
\begin{array}{c}
  B  \\
  C
\end{array}
\right)=
\left \{
\prod_{r=1}^q
\left(
\begin{array}{cc}
\cos\beta_r & (i\sin\beta_r)/\eta_r\\
i\eta_r\sin\beta_r & \cos\beta_r
\end{array}
\right)
\right \}
\left(
\begin{array}{c}
1\\
\eta_s
\end{array}
\right)
\label{matabeles3}
\end{equation}
which is the general expression for thin films theory. The amplitude reflexion coefficient at the entrance of the multi-layer is defined by

\begin{equation}
r=\frac{\eta_0-\eta}{\eta_0+\eta}
\label{reflex1}
\end{equation}
where $\eta=C/B$ is the optical admittance of the assembly. Combining Eqs. (\ref{admittance}) and (\ref{reflex1}), the reflexion coefficient can be written as

\begin{equation}
r=\frac{B\eta_0-C}{B\eta_0+C}
\label{reflex2}
\end{equation}

The reflectance of the multi-layer stack is therefore given by $R=r\times r^{\ast}$. As we are interested in the spectral response of the detector (its absorptance $A$), the model will evaluate the quantity $A(\lambda)=1-R(\lambda)$, assuming that no radiation exits the back of the bolometer. The advantage of this method is that each layer in the stack is only characterized by a matrix and two parameters ($n$ and $d$), making it well suited for computer modeling and optimization.

\subsection{Spectral response of a simple cavity}

The matrix method is applied to the case of the PACS bolometers by considering a stack of several thin layers (see Fig. \ref{Figure2}):  a reflector, a vacuum quarter-wave cavity,  an absorber and  a supporting thin silicon grid. Except for the  quarter-wave cavity, all the other layers can not be considered as simple dielectric layers. The following sub-sections describe for each of these media the characteristic parameters that will be used in the matrix calculation. These  parameters (thickness and refractive index) are listed in Table \ref{table1}. As this method works with semi-infinite layers, the results of the simulation need to be confirmed by 3D finite-element software (see section C. 4).

\subsubsection{Reflector}

In order to get total reflection in the submillimeter wavelength range, the skin depth inside the metal forming the reflector has to be much smaller than the physical thickness.  The skin depth is defined by

\begin{equation}
\delta=\sqrt{\frac{2}{\omega \mu_0 \mu_r \sigma}}
\label{skindepth}
\end{equation}
where $\omega$ is the radian frequency, $\mu_0$ is the permeability of free space ($4\pi \times 10^{-7}$ H/m), $\mu_r$ is the relative permeability of the metal and $\sigma$ its electrical conductivity. For PACS, the metallic reflector consists in a 150 nm layer of gold deposited on a silicon substrate. From \cite{Matula}, the electrical conductivity for gold at  sub-Kelvin temperatures is $5 \times 10^9$ S/m, so at a wavelength of 100 $\mu m$ and with $\mu_r=1$, the skin depth is $\delta \simeq 4$ nm, which is small compared to the gold thickness used in our devices.

In the schematic view of Fig. \ref{Figure3}, this reflective layer corresponds to the substrate, with the difference that no wave is transmitted through it. At the surface of the metallic layer (the boundary $b$), the tangential electric field $E_{b}$ is equal to 0. So $E_{b}=E_{b}^+ + E_{b}^- = 0$ and from \cite{Macleod} the tangential magnetic field is $H_{b} = \eta_1 E_{b}^+ -\eta_1 E_{b}^-$ (the positive sign describes incident waves, along the $z$ axis, and the negative sign describes waves travelling in the opposite direction, $\eta_1$ is the optical admittance of medium 1, the quarter wave cavity). Combining the two equations gives $H_{b} = 2\eta_1 E_{b}^+$. By replacing $E_{b}$ and $H_{b}$ by these new values in Eq. (\ref{matabeles}), the Eq. (\ref{matabeles2}) can be rewritten as

\begin{equation}
\left(
\begin{array}{c}
  E_{a}/E_b^+   \\
  H_{a}/E_b^+
\end{array}
\right)=
\left(
\begin{array}{c}
  B'   \\
  C'
\end{array}
\right)=
\left(
\begin{array}{c}
M\\
\end{array}
\right)
\left(
\begin{array}{c}
0\\
2\eta_1
\end{array}
\right)
\label{matabeles4}
\end{equation}
The optical admittance of the assembly in that special case is $\eta=C'/B'$, so Eq. (\ref{reflex2}) can still be used with $B'$ and $C'$ replacing $B$ and $C$ respectively.

\subsubsection{Absorber}
In the infrared to submillimeter domain, absorbers are traditionally made of thin metal layers whose thickness is adjusted in order to get the appropriate impedance. In Dennison-Hadley filters, it is well known that  the maximum absorption efficiency (100\% at the peak wavelength in theory) is obtained when the impedance of the absorber matches the free space impedance \cite{Fante88}.  In the fields of radar technology and telecommunications,  absorbers with periodic resonant geometrical structures are sometimes used instead of homogenous layers, in order to increase the bandwidth (frequency selective surfaces or FSS, \cite{Langley}). The PACS bolometers were the first detectors to combine these two techniques (Dennison-Hadley filters and FSS) for submillimeter astronomy. In our design, the selected pattern is an array of square loops (Fig. \ref{Figure4}).

Because of the resonant properties of the design, the absorber can not be considered as a simple homogenous lossy medium. Several authors have studied the electromagnetic properties of square loop FSS using equivalent circuit models \cite{{Langley}, {Monacelli}}. They developped expressions for the complex impedance, $Z_{loop}$ of square loop FSS that consist of a series RLC resonant circuit.  It is defined by

\begin{equation}
Z_{loop}=R_s+i\left(X_L+\frac{1}{B_C}\right)
\end{equation}

$R_s$  is the sheet resistance and is responsible for the resistive loss defined by $R_s= 1/\sigma_nd$, where  $\sigma_n$ is the electrical conductivity of the material and $d$ its thickness. The inductance $X_L$ comes from the finite length of the squares and the capacitance $B_C$ comes from the spacing between two loops. $X_L$ and $B_C$ are defined by

\begin{equation}
X_L=Z_0\frac{d}{p}H(p,2s,\lambda)
\end{equation}
and

\begin{equation}
B_C=4Z_0\frac{d}{p}H(p,g,\lambda)
\end{equation}

$H$ is defined in the Appendix A. For a given material and a fixed film thickness, the equivalent sheet resistance of this type of periodic structure is larger than the one of a homogenous film.  To obtain an absorber with an equivalent sheet resistance of 377 $\Omega/\square$, the material composing the loops must have a sheet resistance $R_s=377\times F_R$. In the case of square loops, this reduction factor is at first order $F_R=s/p$ (see Fig. \ref{Figure4} for the description of the geometrical parameters). Electromagnetic simulations with a finite-element software have been performed to get the maximum absorption in the PACS bands and resulted in the following results: $R_s=40 \Omega/\square$, p = 35 $\mu m$, s = 4.4 $\mu m$, g = 4.4 $\mu m$, d = 30.6 $\mu m$.

Choosing the absorbing material is a compromise between different technological constraints like the compatibility with other fabrication processes, the mechanical strength, the film deposition rate and the minimum achievable thickness. We use titanium nitride (TiN) because it satisfies most of these criteria. Given the TiN electrical conductivity at low temperature ($\sigma_n=1\times 10^6$ S/m), from $R_s=1/\sigma_n d$ we deduce the needed thickness, $d$, for impedance matching.  For TiN, $40 \Omega/\square$ correspond to a thickness of 20 nm.

The TiN that is used for our device has a critical temperature $T_c=3.9$ K, it is therefore superconducting during the bolometer operation. Superconducting materials below their critical temperature are nevertheless resistive for AC currents induced by the incoming submillimeter wave. The BCS theory \cite{BCS} introduces the concept of complex conductivity for superconductors which is written $\sigma_s=\sigma_1-i\sigma_2$. In \cite{Mattis}, Mattis and Bardeen derived expressions for $\sigma_1/\sigma_n$ and $\sigma_2/\sigma_n$ that are function of temperature and of the electromagnetic wave frequency ($\sigma_n$ is the normal electrical conductivity of the material at $T_c$). $\sigma_1$ describes the thermally excited normal electrons, and is therefore responsible for absorption of the EM field. $\sigma_2$ represents the superconducting electrons and is ignored in our model \cite{Kautz}. To take into account the superconducting effect, instead of taking the normal sheet resistance $R_s$, we have to consider another expression for TiN:  $R^{\prime}_s=1/\sigma_s d$. In order to build the characteristic matrix of the TiN absorber, the refractive index must be obtained from the value of the complex impedance. Using the expression from \cite{Hilsum}, the complex refractive index of the thin TiN film is

\begin{equation}
\tilde{n}_{abs}=\sqrt{\frac{1}{2\rho \epsilon_0\omega}}(1-i)
\end{equation}
with  $\rho=Z_{loop}\times d$.

\subsubsection{Silicon grid}

Because the TiN layer is too thin to be self-suspended, it is  deposited on a 5 $\mu$m thick monocrystalline silicon grid that also contains the semiconducting thermometer (see Fig. \ref{Figure2}). In \cite{Motamedi}, Motamedi et al.  have estimated the effective refractive index of such subwavelength microstructures. This grid has an effective refractive index calculated by the following expression:
\begin{equation}
n_{eff}=\left[\frac{(1-f+fn_{Si}^2)\left[(1-f)n_{Si}^2+f\right]+n_{Si}^2}{2\left[(1-f)n_{Si}^2+f\right]}\right]^{1/2}
\end{equation}

where $f$ is the silicon filling factor of the grid (61$\%$), $n_{Si}$ is the refractive index of bulk silicon (3.4) and therefore $n_{eff}=2.2$.
The presence of this 5 $\mu$m silicon grid in the pixel cavity will slightly modify the spectral response compared to the simple case ``reflector / absorber''.

\subsubsection{Simuation results}

To validate the  method of characteristic matrix as a pertinent simulation tool, the model is used to simulate the absorption of a PACS pixel (quarter-wave cavity of height $d_{c}=20$ $\mu$m and TiN loops with a pitch of  $p=35$ $\mu$m). The result is then compared to a simulation made with a finite element electromagnetic simulation software, Ansoft HFSS\texttrademark  (see Fig. \ref{Figure5}).

The curve \textit{a} in Fig.  \ref{Figure5} corresponds to the case of a simplified cavity made of a free-standing uniform absorber (with a surface impedance of $377 \Omega/\square$, not superconducting) located 20 $\mu$m above a reflector. The spectral response is maximum at  80 $\mu$m which correponds to $\lambda=4 d_{c}$, as expected for Dennison-Hadley filters. The sudden absorption decrease toward the short wavelengths (near 40 $\mu$m) corresponds to the ``zero''  of these devices, which occurs at  $\lambda=2 d_{c}$. Adding a supporting 5 $\mu$m silicon grid above the absorber shifts the peak toward longer wavelengths (curve \textit{b}). Even if the response is very high in the case of a uniform absorber, its profile is not flat and cannot optimally cover the two PACS bands represented in blue and purple in Fig. \ref{Figure5}. This limitation is overcome by introducing the textured  absorber (curve \textit{c}).  The  absorption is relatively constant over the entire PACS band and still very high (around 90\%). The result  is very similar to the HFSS modeling (curve \textit{d}) which gives credit to the matrix method for this kind of simulation.

As it has been previously described, our model can simulate the effect of the superconductivity of TiN, for which HFSS is limited. When the effect of superconducting TiN is introduced, the long wavelengths absorption decreases compared to the case of normal TiN (curve \textit{e}). This device is limited to operation up to $\sim$ 350 $\mu$m (when the absorption drops below 70\%). This simulated absorption is compared to measurements in section 3.

\subsection{Enhancing the Response at Long Wavelengths}

\subsubsection{Demonstrator at 450 $\mu$m}

The matrix method is easy to modify and runs fast on a personnal computer (it takes a few seconds to obtain the curves of Fig. \ref{Figure5}). Therefore it is more adapted to test different design options than a typical finite element software. As a demonstration and example, the target band is 450 $\mu$m (425 - 470 $\mu$m), which corresponds to an atmospheric transmission band that is accessible from ground-based telescopes located on dry and high sites. Based on the idea of optical systems that use AR layers to improve reflection or transmission in a particular band, our development consists in an AR layer placed at the front-end of the bolometer array (this structure is called PACS+AR thereafter). The free parameters for the design are: (i) the distance between the dielectric and the silicon grid of the bolometer, called airgap, (ii) the thickness of the AR dielectric layer in silicon, see Fig. \ref{Figure6}b.

The model tests the different airgap/AR combinations and estimates, for each of these cases,  the quality of the spectral response in the  450 $\mu$m band. Two criteria are evaluated to characterize the response: the average absorption coefficient in the band $\alpha$, and its flatness index $\gamma$. The flatness index is defined by the average deviation from $\alpha$  ($\gamma=100\%$ for a perfectly flat response and 0\% for a step profile). We use a single performance coefficient ($C_{abs}=\alpha \gamma$)  to find the optimum parameters that provide the best response in the band. Results are displayed in the form of a 2D map (Fig. \ref{Figure6}a). It  shows that different combinations of thicknesses give good results, but not all of them are easily feasible. Solution \textit{A} for example, which gives the best performance, corresponds to a very thin AR layer (13 $\mu$m) located just  2 $\mu$m above the PACS grid. Even if this solution is technically possible to build, it would require a complete design study, which is not the goal of this work.  The solution \textit{B}, which also gives a high response efficiency, requires the insertion of a 51 $\mu$m thick silicon layer at a distance of 179 $\mu$m (airgap) above the bolometer grid. As the interpixels walls have a fixed height of  450 $\mu$m because of the etching process (Fig. \ref{Figure2}a), this solution would require a silicon waffle shaped structure encapsulated in the PACS array. Similar structures have been made in our laboratory, and were successfully mounted on existing PACS arrays. For technical and practical reasons, we first focused on a simpler solution, (\textit{C}), that gives a lower $C_{abs}$ coefficient (mainly because the response is not flat),  but which is technically easier to implement: a 138 $\mu$m thick silicon layer is deposited (glued) directly on the top of the 450 $\mu$m interpixel walls. Because of this simplicity of assembly, this solution has been selected to experimentally validate our method (see section 3).

Once the 2D map is obtained by the model ($\sim$ 30 minutes of calculation time on a typical PC), the chosen solution is studied more in details (comparison with HFSS\texttrademark ).  Fig. \ref{Figure7}a shows the corresponding spectral response of solution \textit{C}. The average absorption coefficient is 88$\%$ in the 450 $\mu$m band with HFSS\texttrademark , 71\% with the matrix method for normal TiN and 65\% for superconducting TiN. The different curves are in very good agreement between 100 $\mu$m and 440 $\mu$m, but the matrix method shows a larger dip near 480 $\mu$m compared to the HFSS\texttrademark  case. The improvement in spectral response is  significative compared to the bare bolometer pixel (43$\%$ absorption). To use this detector in a scientific instrument, the parasitic peaks of absorption at shorter wavelengths (below 400 $\mu$m) need to be strongly attenuated with a combination of long-pass  and band-pass optical filters. The model has also been used to test the influence of the angle of incidence on the spectral response of the detector. Results on Fig. \ref{Figure7}b show that the absorption is constant up to 20$^{\circ}$ which is good enough for the requirements of a scientific bolometer camera (the final f-number is typically between 3 and 5 in a submillimeter camera with filled arrays, \cite{Talvard}).

\subsubsection{350-735 $\mu$m  Coverage}
Based on this method, we have investigated the possibility to cover all the atmospheric windows between 350 $\mu$m and 735 $\mu$m with a 20 $\mu$m $\lambda$/4 cavity PACS array topped with an adapted AR layer. The results corresponding to the best performance are presented in Table 2 and in Fig. \ref{Figure9}.

For each atmospheric band considered in this example, there is a particular airgap/AR combination that improves the spectral response. Except for the 350 $\mu$m band, the absorption is improved by a minimum factor 2 (6 in the 735 $\mu$m band). All these solutions require waffle shaped structures inserted in the original array.

\section{Experimental Results}

\subsection{Spectrometer Characterization}

We used a polarizing Fourier transform spectrometer (Martin-Puplett) to measure the spectral response of the bolometer arrays with or without an AR layer.  The experimental setup is detailed in Appendix B. In this setup, the global absorption of the $16 \times16$ pixels array is deduced from the reflected signal of the FTS beam on its surface. Because the incident beam is larger than one pixel and because it is not normal to the surface (the incident angle is $\sim$ 5$^{\circ}$), the interpixel silicon walls add a small scattering effect  which results in oscillations in the spectral response. The model has been modified in order to take this effect into account, and the result can be seen in Fig. \ref{Figure9}a for the normal PACS array case. Fig. \ref{Figure9}b shows the spectral response of the PACS+AR layer (solution \textit{C}). The experimental data look very similar to the model, with an average absorption of 74\% in the 450 $\mu$m band.

\subsection{Bolometer camera on a telescope}

We designed a camera for astrophysical observations in the 450 $\mu$m band equipped with a $16\times 16$ PACS+AR array, similar to the one characterized with the FTS. This instrument is called p-ArT\'eMiS \cite{Talvard}, and was installed at the Cassegrain focus of the APEX telescope in the Atacama desert in Chile. During the different runs (in 2007 and 2009), the detector showed the expected performances in terms of optics and sensitvity \cite{{Andre},{Minier}}.

\section{Conclusion}

Large arrays made of bolometers using  quarter wave cavities are now commonly used in submillimeter cameras for astrophysics. Once assembled, it is not easy to modify the intrinsic spectral properties of these detectors. However, there are cases where it is interesting to use an array that was originally designed for a particular band to operate in other bands. For this purpose, our group has developed a technique using a front end anti-reflecting dielectric layer that enhances the spectral response of bolometer arrays in other windows. To get the optimum parameters of the dielectric layer, we have developed a model based on the method of characteristic matrix for thin films. The results of the model have been compared to outputs from Ansoft HFSS\texttrademark and show very good accordance.

We applied this general method to the case of the Herschel PACS bolometer arrays which was developed for the 60 $\mu$m - 210 $\mu$m window.  The cavity of the PACS detectors is formed by the hybridization of two layers with 20 $\mu$m indium bumps. We showed that it is possible to have a good spectral response for all the atmospheric transmission windows between 350 $\mu$m and 735 $\mu$m by adding a dielectric layer (silicon) with a thickness calculated by the model, over the original array. This design has been tested and validated experimentally in a spectrometer, and used for science purpose in a small submillimeter camera.

\section*{Appendix A: Details of the parameters for the square loops resonance.}

$H$ is defined by

\begin{equation}
H(p,s,\lambda)=\frac{p}{\lambda}\cos \theta
\left[
\ln\left(\frac{1}{\sin\frac{\pi s}{2p}}\right)
+G(p,s,\lambda)
\right]
\end{equation}
where $\theta$ is the incident angle and

\begin{eqnarray*}
\lefteqn{G(p,s,\lambda) =}  \\
&& \frac{1}{2}\frac{(1-\phi^2)^2\left[ \left(1-\frac{\phi^2}{4}\right) (A_++A_-)+4\phi^2A_+A_- \right]}
{\left(1-\frac{\phi^2}{4}\right) +\phi^2\left(1+\frac{\phi^2}{2}-\frac{\phi^4}{8}\right) (A_++A_-)+2\phi^6A_+A_- }
\end{eqnarray*}
where

\begin{equation}
A_\pm=\frac{1}{\sqrt{1\pm\frac{2p\sin\theta}{\lambda}-\left(\frac{p\cos\theta}{\lambda}\right)^2}}-1
\end{equation}
and

\begin{equation}
\phi=\frac{\sin\pi s}{2p}
\end{equation}

\section*{Appendix B: Martin-Puplett FTS}

Our spectrometer has a typical resolution of 0.25 cm$^{-1}$ in the 100 to 700 $\mu$m band and operates at cryogenic temperatures. Measurements were made in reflective mode by comparison with a perfectly reflecting mirror (see Fig. \ref{Figure10}). By considering that the power which is not reflected by the bolometer array is entirely absorbed, the spectral response is calculated with $A=1-R_{Array}/(C\times R_{Mirror})$, where $R_{Array}$ is the signal reflected from the bolometer array,  $R_{Mirror}$ is the signal reflected from the mirror and $C$ is a geometrical correcting factor.  The pixel response is obtained from the global response of the array.

redpajama_set_name: RedPajamaArXiv


text:
Luncheon To Mark County's First Championship Triumph In 1964
Sunday, August 3rd, 2014
Worcestershire are staging a luncheon to commemorate the 50th anniversary of the county's 1964 County Championship title triumph in the Chestnut Marquee during Saturday's home Royal London One-Day Cup with Lancashire.
The county won the title for the first time by 41 points from Warwickshire after winning 18 of their 28 games – and then retained it the following year and finished runners-up in 1966.
Paceman Jack Flavell was named one of Wisden's Cricketers of the Year after taking 101 wickets including 46 in five matches during August after returning from injury.
For good measure Flavell picked up another 132 wickets in 1965 and 135 in 1966 at the age of 37 and passed the 100 wicket mark eight times.
He finished his career with 1, 529 wickets and his partnership with Len Coldwell was one of, if not the greatest in Worcestershire's history.
Many of the surviving members of that memorable 1964 squad will be attending the luncheon including Tom Graveney, Roy Booth, Norman Gifford, Dick Richardson, Doug Slade, Bob Carter and Ducan Fearnley.
It is also hoped that Ron Headley and Alan Ormrod will be able to attend.
Supporters can also be part of that luncheon by taking advantage of a superb offer.
For just £35 they can obtain ground admission for the Lancashire game, a three course luncheon and also be part of a question and answer session with members of the 1964 team.
It promises to be a day of unforgettable nostalgia and reminisces.

redpajama_set_name: RedPajamaCommonCrawl


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Nordic Marketplace and Luncheon Benefit for Vesterheim Museum
DECORAH, Iowa — The Chicago Friends of Vesterheim Norwegian-American Museum invites everyone to The Nordic Marketplace and Luncheon on Saturday, March 28, at the Park Ridge Country Club in Park Ridge, Illinois.
Wooden container with chip carving by Marvin Bruha.
The Marketplace and Silent Auction will be from 9:30 a.m. to 12:30 p.m. The featured speaker will be Norwegian Honorary Consul from Minneapolis and former Vesterheim Board Chair, Gary Gandrud. The Marketplace will feature artwork and gifts with a Scandinavian theme, such as jewelry, fine art, books, clothing, textiles, woodworking, rosemaling, bunads (Norwegian costumes) for dolls, and more. Marketplace vendors include Vesterheim, Country Gallery Antiques, Hjertehjem, Jock Holmen, Illinois Norsk Rosemalers' Association, Vivian Morrison and Carole Floate, Nordic Designs, Mona Randem, Sally Schoch, Elea Uhl, and others. The Silent Auction will have wonderful and affordable items, including three beautiful chip-carved pieces by Marvin Bruha, a lovely Hardanger centerpiece, and a Swedish embroidered child's cap.
The Luncheon will be at 12:30 p.m. and will include a greeting from Norwegian Honorary Consul General from Chicago Paul S. Anderson.
Tickets are $50 per person. Seating is limited. Advanced reservations are necessary and should be made by March 23. For further information please contact Vesterheim at 563-382-9681, info@vesterheim.org, or check the museum's website at vesterheim.org.
Hand embroidered child's cap. Photo courtesy of Vesterheim Norwegian-American Museum.
The Chicago Friends of Vesterheim Committee includes Robert and Evy Alsaker—co-chairs, Liz Ahlgren, Roar Broch, Karen Brunssen, Richard Fjeldheim, David Hoyem, Laurie Kosky, Kand and Kathy Larson, Peter, Martha, and Emma Nielsen, Ken and Julie Nordan, Lowell and Helen Olberg, and Norma Altern Smith.
Co-chair Evy Alsaker said, "We're excited to welcome several new vendors as well as returning vendors to this year's Marketplace. Additionally, there will be live demonstrations of weaving, woodcarving, woodworking and rosemaling. As always the food and service at the newly redecorated Park Ridge Country Club is superb! Join us for this unforgettable event!Proceeds of the event will benefit Vesterheim's restoration of King Olav the V's 1951 Cadillac limousine.
Vesterheim uses the story of Norwegian Americans to explore aspects of identity and culture common to everyone. The museum cares for over 24,000 artifacts, among which are some of the most outstanding examples of decorative and folk art to be seen in this country. Founded in 1877, Vesterheim is the oldest and most comprehensive museum in the United States dedicated to a single immigrant group. This national treasure includes a main complex of 16 historic buildings in downtown Decorah, and an immigrant farmstead and prairie church just outside the city.
From May 1 – Oct. 31, Vesterheim is open daily, 9 a.m. – 5 p.m., with hours extended until 8:00 p.m. on Thursdays. From Nov. 1 – April 30, Vesterheim is open Tuesday through Sunday 10 a.m. – 4 p.m., with hours extended until 8:00 p.m. on Thursdays and is closed Monday. For more information on the museum's exhibits, activities, and membership opportunities, consult Vesterheim's website at vesterheim.org, call (563) 382-9681, or write to Vesterheim Norwegian-American Museum, 523 W. Water St., P.O. Box 379, Decorah, IA, 52101-0379.
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I was so desperate to look like Ricky Martin that I spent nearly £ 8,000 on 30 surgeries
By Shana Cavanaugh Last updated Dec 26, 2021
A MAN announced that he had undergone 30 cosmetic surgeries and spent nearly £ 8,000 to look like Ricky Martin.
Francisco Mariano Javier Ibanez from Buenos Aires, Argentina, 33, has admitted his addiction to plastic surgery.
Francisco Mariano Javier Ibanez said people told him he looked like Ricky Martin so he had 30 surgeries to look more like himPhoto credit: Newsflash
Francisco before his weight loss and plastic surgery tripPhoto credit: Newsflash
Francisco started making changes to look like Livin 'La Vida Loca singer Ricky MartinImage Credit: Getty – Contributor
He said that his desire to look like Ricky Martin began a long time ago when people noticed that there was a resemblance between him and the Puerto Rican singer.
Francisco said, "It started a long time ago when they told me I had a touch of Ricky Martin.
"I took it as a joke, but I started making some changes and the resemblance grew bigger."
Then he decided to go all the way and said, "I got a picture of him, I realized that I like him and like everything in life, if I like something I do it."
Francisco, who said he was "born for TV and cameras" and "felt."[s] incredible "Now when people ask him for a selfie on the street, he admits he regrets changing his looks to look like someone else.
Although he has now spent around £ 7,290 on cosmetic procedures, he said, "Now I can see that the ideal is to be yourself and not someone else.
"But it took a while to realize that."
In a recent interview on Argentine TV station Cronica HD, the Ricky Martin doppelganger confirmed his habit of cosmetic surgery and said, "I think that at some point in your life the addiction develops and then gets worse."
Francisco spoke frankly about his mental state at the time of the procedures and said, "When I started the operation, I knew things were getting out of hand and that there
Today Francisco is a qualified ontological coach specializing in neurosciences.
He looks like a completely different person these days, but previously told reporters that after seven years of changes, he still hasn't gotten used to his new body.
He made the admission after appearing on an Argentine weight loss reality show called "Cuestion de Peso" ("A Question of Weight") in 2018, in which he lost over 90 kg.
He told TeleShow at the time: "When I walked in, I had high blood pressure, high glucose and muscle pain.
"By losing weight, I no longer hurt anything and I no longer have a guilty conscience.
"But such a change in life scared me a bit. It was a bit like starting from scratch.
"Even today, seven years later, I still find it difficult to get used to my new body.
"People tell me 'you're divine, look how you were before,' but it's not that easy."
Although he has now spent around £ 7,290 on cosmetic procedures, he now regrets the operationsPhoto credit: Newsflash
He's spent around £ 7,290 on cosmetic proceduresPhoto credit: Newsflash
We shared which celebrities had botox, from Courteney Cox to Tulisa.
In more cosmetic surgery news, cheek fillers changed the appearance of celebrities like Chloe Ferry.
And that's all you need to know about cheek fillers – from its cost to its estimated lifespan.
I forgot what my face looked like after turning $ 15,000 into a doll, but I'm done
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Alex Scott's failed date with Coronation Street's Sam Robertson:…
Bella Hadid plastic surgery: model denies having fillers and rhinoplasty
Tail End Takes A Foremost Place In Plastic Surgery Offices – Consumer Health…


Join the Digital Transitions team at Parkwood Studios in Phoenix to see how the new XF IQ4 Camera System makes the future of imaging possibilities endless. The DT team will share their knowledge on the new XF IQ4 and you'll have the chance to shoot it yourself.
Located 5 minutes from Sky Harbor Airport, and with easy access from State Route 51 or the Loop 202 freeway.


I read an interesting article a while ago in which the exciting director, Robert Icke, discussed theatre's challenge to compete with TV shows such as The Sopranos. His refreshing and grounded approach is what London's theatre scene needs right now. Maybe I like Icke, really like Icke, because he consistently mentions Tony Soprano and the gang. Oresteia was wonderful, too, for that matter. Icke continues to pry into his role as the associate director at the Almeida Theatre by tackling another tall task- adapting Chekhov's Uncle Vanya. Although it does not leave a lasting impression as powerful as that garnered by Oresteia last year, it is a strong production. It is thoroughly enjoyable with some masterful touches.
Uncle Vanya is one of Chekhov's later plays. A family are suspended in constant ennui, toiling against life's struggles, reveling in its absurdity. They decay slowly on a large estate in provincial Russia. They spend their time bickering as life ebbs on. Loves remain unrequited, arguments remain fierce and everyone generally struggles. Icke transports the drama to the modern day, skillfully tailoring the script along the way. Uncle Vanya becomes Uncle John- or Johnny, which matches the colloquial Russian roots of the name Vanya. The production is boosted by excellent performances all round. Tobias Menzies portrayal of the opinionated and meddling doctor, Michael is particularly accomplished. Menzies' performance is matched by Jessica Brown Findlay's feisty portrayal of Sonya.
Icke's Uncle Vanya sticks faithfully to Chekhovian Naturalism and the tweaked script is excellent. There are some points which fall short; a scene in which some of the drunken characters break into a rendition of Iggy Pop's Lust for Life feels a little overwritten. Chekhov masterfully balances tragedy and comedy; sometimes this production falls short on humour. Nevertheless, as tensions grow, this production retains intensity throughout.
Icke's production makes beautiful use of space. There are moments which touch upon a cinematic feeling. A good deal of credit must be directed towards Hildegard Bechtler (Set) and Jackie Skemesh (Light). The plot unfolds on a revolving stage as we are lulled and hypnotised by this bleak, absurd world. It spins round and round, gently. I'd be interested to know if any of the cast suffer from motion sickness. The revolving mechanism treats us to a stand-out moment in Act III. The cast have their backs to us and our view is obstructed by a glass drinks cabinet. Our attention is refracted through the glass, which creates a momentary distance between stage and audience. Candles and lamps flicker on and off, off and on, consistently toying with darkness and light with delicate subtlety.
At three hours and fifteen minutes long, Uncle Vanya is a lengthy production. Not that you necessarily feel it. Each act is followed by a ten minute interval (three intervals in total). Rather than disrupt, this allows the drama to recharge itself, and these intervals are summative to the production's episodic structure. The evening feels like one of those Tuesday nights spent watching four episodes of The Sopranos on Putlocker; engrossing and enjoyable, with plenty of time for toilet and refreshment breaks. Icke must be doing something right.


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International Bioacoustics Society (IBAC)
IBAC Committee
IBAC meetings
2022 IBAC Congress
Older IBAC meetings
European Bioacoustic Collections Network
How to give a presentation at an IBAC meeting
Advances in Bioacoustics II
Selected papers from the XX International Bioacoustics Congress (Piran, Slovenia, 2005).
Published as "Advances in Bioacoustics II", a special issue by the Slovenian Academy of Sciences and Arts in Razprave IV. razreda SAZU, vol 47(3) (2006).
Authors' guidelines.
Editors: Matija Gogala & Tomi Trilar
Recommended citation style:
Advances in Bioacoustics 2, Dissertationes Classis IV: Historia Naturalis, Slovenian Academy of Sciences and Arts (Ljubljana), XLVII-3.
(Full papers are in Adobe pdf format: to read these you may need to download the free Adobe Acrobat PDF viewer).
Introduction M Gogala Full paper (2540 KB)
Stink bug communication through plants during mating Andrej Cokl Abstract Full paper (154 KB)
Entropy calculations for measuring bird song diversity: The case of the White-vented Violet-ear (Colibri serrirostris) (Aves, Trochilidae) Maria Luisa da Silva & Jacques Vielliard Abstract Full paper (367 KB; updated version to correct printing error)
Differences between the auditory system of humans and Bottlenose Dolphins Gennadi L. Zaslavskiy Abstract Full paper (2616 KB)
Teaching a musical code to a parrot: Frequency discrimination and the concept of rhythm in a Grey Parrot (Psittacus erithacus) Luciana Bottoni, Simone Masin, Daniela Lenti & Boero & Renato Massa Abstract Full paper (540 KB)
Individual recognition of Scops Owls (Otus scops) by spectrographic analysis of their calls: a preliminary study Katarina Denac & Tomi Trilar Abstract Full paper (225 KB)
Interspecific territorial vocal activity of the Ural Owl (Strix uralensis) towards Tawny Owl (Strix aluco), sympatric owl competitor: A playback experiment Petra Vrh & Al Vrezec Abstract Full paper (70 KB)
Social context and response to female voice: Audience effect in the male Zebra Finch (Taeniopygia guttata) Nicolas Mathevon, Clémentine Vignal, Stéphane Mottin & Thierry Aubin Abstract Full paper (290 KB)
Vocal imitation in African Savannah Elephants (Loxodonta africana) Joyce H. Poole, Peter L. Tyack, Angela S. Stoegerhorwath & Stephanie Watwood Abstract Full paper (800 KB)
Acoustic features of Red Deer (Cervus elaphus) stags vocalizations in the Cansiglio Forest (NE Italy, 2001-2002) Andrea Favaretto, Renzo De Battisti, Gianni Pavan& Alberto Piccin Abstract Full paper (2230 KB)
The animal sound archive at the Humboldt-University of Berlin: Current activities in conservation and improving access for bioacoustic research Karl-Heinz Frommolt, Rolf Bardeli, Frank Kurth & Michael Clausen Abstract Full paper (280 KB)
Fonozoo.com a new resource in the web for the study of animal sounds Gema Solís, Xavier Eekhout & Rafael Márquez Abstract Full paper (950 KB)
Acoustic website on European singing cicadas Matija Gogala Abstract Full paper (1600 KB)
Acoustic playback: Contributions to the study of animal communication in the last 13 years (1992-2004) Xavier Eekhout, Gema Solís & Rafael Márquez Abstract Full paper (95 KB)
Software tools for automatically detecting, measuring and classifying animal sounds Raimund Specht Abstract Full paper (230 KB)
Bird sound classification and recognition using wavelets Arja Selin, Jari Turunen & Juha T. Tanttu Abstract Full paper (1500 KB)
De-noising aspects in the context of feature extraction in automated bird sound recognition Jari Turunen, Arja Selin, Juha T. Tanttu & Tarmo Lipping Abstract Full paper (820 KB)
Sound recording of vocal activity of animals inhabiting subtropical forest on Iriomote Island in the southern Ryukyus, Japan Shinichi Watanabe & Hiroki Kobayashi Abstract Full paper (370 KB)
Acoustic behaviour in Malawian Cichlids (Pseudotropheus, Cichlidae): Potential cues for species recognition and intraspecific communication Jose Miguel Simões, Ines Duarte, Paulo Jorge Fonseca, G. F. Turner & M. Clara P. Amorim Abstract Full paper (310 KB)
Individuality in the mating call of the male Lusitanian Toadfish (Halobatrachus didactylus) M. Clara P. Amorim & Raquel O. Vasconcelos Abstract Full paper (640 KB)
Cues to orientation of a caller to a listener in biphonic and non-biphonic close range contact calls in the Dhole (Cuon alpinus) Ilya A. Volodin, Michael M. Nagaylik & Elena V. Volodina Abstract Full paper (640 KB)
The ocurrence of nonlinear vocal phenomena in frustration whines of the Domestic Dog (Canis familiaris) Elena V. Volodina, Ilya A. Volodin & Olga A. Filatova Abstract Full paper (470 KB)
Group and individual discriminability in monozygotic twins' infant cry: A pilot study Daniela Lenti Boero & Francesca Rocca Abstract Full paper (100 KB)
Stink bug communication through plants during mating
Andrej Cokl (Nacionalni inøtitut za biologijo, Ljubljana, Slovenia)
Advances in Bioacoustics 2, Dissertationes Classis IV: Historia Naturalis, Slovenian Academy of Sciences and Arts (Ljubljana), XLVII-3, pp7–35 (2006)
Full paper (pdf file, 154 KB)
Different aspects of substrate-borne sound communication in stink bugs are reviewed. Vibrational communication follows aggregation on the same plant, enables mate location and together with other senses promotes species recognition and copulation. Stink bug vibratory signals produced by body vibrations are transmitted with low attenuation through green host plants which resonant frequency is tuned with signal spectral characteristics. This phenomenon enables communication through the same plant at the distance of up to several meters. Species specific male and female calling and courtship songs were recorded, analyzed and described in more than 20 species of the subfamily Pentatominae. Male-male vibratory interaction occurs during rivalry. All recorded vibratory emissions have similar frequency characteristics with the fundamental and dominant frequency around 100 Hz and harmonic peaks generally not exceeding 500 Hz. Species and sex specificity of signals is preserved in their amplitude modulation and time pattern. The subgenual organ, leg joint chordotonal organs and campaniform sensilla together with antennal mechanoreceptors constitute the receptor system which sensitivity exceeds the intensity of emitted signals for about 60 dB. Male vibrational directionality is enabled by resolution.
Entropy calculations for measuring bird song diversity: The case of the White-vented Violet-ear (Colibri serrirostris) (Aves, Trochilidae)
Maria Luisa da Silva (Universidade Federal do Pará, Brazil) & Jacques Vielliard (Universidade Estadual de Campinas, Brazil)
Advances in Bioacoustics 2, Dissertationes Classis IV: Historia Naturalis, Slovenian Academy of Sciences and Arts (Ljubljana), XLVII-3, 37–49 (2006)
Full paper (pdf file, 367 KB; updated version to correct printing error)
The White-vented Violet-ear (Colibri serrirostris) is a common and brilliantly colored Brazilian hummingbird that sings a series of high-pitched and evenly spaced short notes with a repertoire size of 3 to 5 note types. We analyzed the song of 17 individuals from 10 localities in relation to note types, repertoire size and non-conditioned and conditioned entropy. Despite the small repertoire size, each singer presented different note types and sequences. Neighbors can share note types, but maintain distinct sequences and entropy values. The entropy values were useful to objectively differentiate between more or less versatile songs with the same repertoire size. Conditioned entropy, a calculation that shows the distribution of the combinations of two consecutive notes, revealed the more versatile singers, which were not evident from the repertoire size only nor the non-conditioned entropy. Despite the rare presence of note sharing in our sample, we did not find any cue of dialects or geographic patterns of variation, but individual variation. The variability of C. serrirostris song in note structures, sequences and entropy is evidence of vocal learning and creative capacity, a poorly described communication strategy in non passerine birds.
Differences between the auditory system of humans and Bottlenose Dolphins
Gennadi L. Zaslavskiy (Tel-Aviv University, Israel)
Full paper (pdf file, 2616 KB)
There is a widely accepted notion of functional similarity between the auditory system of dolphins and humans. Although similarities mostly concern the perception of tone-like signals, dolphins are believed to process high frequency echolocation clicks using the same auditory mechanisms known for humans. Contrary to this view we found that, at least as far as the auditory analysis of the brief signals associated with the dolphin sonar is concerned, there are more functional differences between Bottlenose Dolphins (Tursiops truncatus) and humans than similarities. With the time resolution as high as 0.02-0.03 ms the auditory system of Bottlenose Dolphins is a time domain analyzer rather than a frequency analyzer. The spatial hearing in dolphins appears to be based on directional reception and transmission and performs similarly to a monaural rather than the binaural system of humans. There are some functional differences between the auditory systems of humans and dolphins even at audio frequencies of humans hearing.
Teaching a musical code to a parrot: Frequency discrimination and the concept of rhythm in a Grey Parrot (Psittacus erithacus)
Luciana Bottoni, Simone Masin, Daniela Lenti (Università degli Studi Milano Bicocca, Italy) & Boero & Renato Massa (Università della Val D'Aosta, Italy)
Music competence and perception should be considered in evaluating human cognitive processes, unfortunately, evolutionary onset of music is still unclear. Although connections between human language and other animal communication patterns remain limited and controversial, humans share musical "language" at least with birds. Recently, many studies seem to point out that in many vertebrate species' song there could be structures comparable to those of human music. African Grey Parrot (Psittacus erithacus) is well known for his ability in song and speech learning. In our study we tried to understand if a female African Grey, Theo, were able to learn and properly use some basic elements of the musical language, in particular we choose the intonation and rhythm. We taught first Theo to answer with sequences of "notes" to some simple melodies played with an electric piano, then we recorded every "musical" output sung by Theo. Peak frequency analysis and comparison between parrot's sequences and random generated strings, confirmed the acquisition of the intonation concept and notes amplitude peak showed Theo's tendency to maintain a rhythmic regularity. Furthermore, data analysis stressed the great complexity and innovation in the musical sequences uttered by the bird, that led us to exclude the simple imitation process.
Individual recognition of Scops Owls (Otus scops) by spectrographic analysis of their calls: a preliminary study
Katarina Denac (Ljubljana, Slovenia) & Tomi Trilar (Slovenian Museum of Natural History, Ljubljana, Slovenia)
Numerous studies have confirmed that males of several species can be individually identified by spectrographic analysis of their vocalizations. Spectrographic analysis of 12 recordings of Scops Owl (Otus scops) males made on Ljubljansko barje (central Slovenia) and in Istria (NW Croatia) revealed that this method is suitable for individual recognition of males. Average values for the following three parameters of calls were calculated (±SE): length of call 278.3±3.69 ms (min 228-max 371 ms), time interval between calls 2.72±0.05 s (min 2.08-max 3.39 s) and fundamental frequency of call 1.32±0.01 kHz (min 1.17-max 1.50 kHz). Discriminant function analysis successfully separated recordings of different males on the basis of above mentioned parameters (Wilkins'?=0.0027, P<0.001). Variables considered in the model were length of call and time interval between calls, whereas fundamental frequency was omitted as its variance between individuals was too low. Both discriminant functions were statistically significant (p<0.001), the first one accounting for 90% of variance, and both together for 100% of variance. Considering the fact that Scops Owls may form larger calling groups and may breed in loose colonies where conditions are favourable, this method represents a very important tool for accurate determination of the number of calling males. Recordings of Scops Owl are relatively easy to obtain as the species is highly vocal and males respond well to playback of another male. The method is also less time-consuming for the surveyor and less disturbing for the bird, compared to capturing and banding.
Interspecific territorial vocal activity of the Ural Owl (Strix uralensis) towards Tawny Owl (Strix aluco), sympatric owl competitor: A playback experiment
Petra Vrh (Ribnica, Slovenia) & Al Vrezec (National Institute of Biology, Ljubljana, Slovenia)
Advances in Bioacoustics 2, Dissertationes Classis IV: Historia Naturalis, Slovenian Academy of Sciences and Arts (Ljubljana), XLVII-3, 99–105 (2006)
Full paper (pdf file, 70 KB)
Territoriality in birds is more often displayed as vocal communication than as aggressive attack, so playback experiments are commonly used approach in studying territorial interactions. We tested the interspecific territoriality of the Ural Owl (Strix uralensis) towards closely related and smaller sympatric owl competitor, the Tawny Owl (Strix aluco). We preformed playback experiments on 28 territories of Ural Owls on Mt. Krim (central Slovenia) during spring and autumn between years 2003 and 2005. We measured the response rate of the Ural Owl on the broadcast territorial song of the male of the Ural, Tawny, and Great Grey Owl (Strix nebulosa). The last is playback of allopatric species used as a control and was considered as a non-territorial response versus conspecific playback of the Ural Owl considered as a territorial response. Ural Owl territorial vocal activity was very low since response rate reached only 34%. However, in the analysis we confirmed that Ural Owl was interspecific territorial towards Tawny Owl since the level of response of the Ural Owl to the Tawny Owl playback was as similar as to the conspecific playback. Therefore we are concluding that interspecific territoriality is a very important mechanism in spatial segregation of these two highly competitive species.
Social context and response to female voice: Audience effect in the male Zebra Finch (Taeniopygia guttata)
Nicolas Mathevon (Université Jean Monnet, France), Clémentine Vignal ('The BioAcoustics Team', Université Paris XI, France), Stéphane Mottin (Université Jean Monnet, France) & Thierry Aubin ('The BioAcoustics Team', Université Paris XI, France)
Advances in Bioacoustics 2, Dissertationes Classis IV: Historia Naturalis, Slovenian Academy of Sciences and Arts (Ljubljana), XLVII-3, 107–116 (2006)
How behaviour and underlying brain functions are shaped by social context remains a poorly explored domain. Here, we review two recent studies on Zebra Finches (Taeniopygia guttata) which focus on this question. In this species, communication behaviour within male and female pair appears to be strongly regulated by the presence of other individuals. Investigation at brain level shows that the sound-induced immediate early gene response is also highly sensitive to the audience effect.
Vocal imitation in African Savannah Elephants (Loxodonta africana)
Joyce H. Poole (Amboseli Trust for Elephants, Kenya), Peter L. Tyack (Woods Hole Oceanographic Institution, USA), Angela S. Stoegerhorwath (University of Vienna, Austria) & Stephanie Watwood (Woods Hole Oceanographic Institution, USA)
There are a few mammalian species that can modify their vocalizations in response to auditory experience. We describe two examples of vocal imitation by African Savannah Elephants (Loxodonta africana), a terrestrial mammal that lives in a multitiered fission-fusion society. The first case of vocal imitation involves Mlaika, an adolescent female African Elephant who lived in a semi-captive group of orphaned elephants in the Tsavo National Park, Kenya. Trucks were audible from a highway 3 km from the night stockade. Mlaika emitted truck-like sounds for several hours after sunset, the optimal time for the transmission of low frequency sound in African savannahs. The second case involves Calimero, an adult male African Elephant who spent 18 years living with two female Asian Elephants (Elephas maximus) at the Rome zoo. Calimero imitated the chirping sounds typically produced by Asian Elephants, though not by African Elephants. Our findings favour a role for vocal imitation that has already been proposed for primates, birds, bats and marine mammals: it is a useful form of acoustic communication that helps to maintain individual-specific bonds within social changing groupings.
Acoustic features of Red Deer (Cervus elaphus) stags vocalizations in the Cansiglio Forest (NE Italy, 2001-2002)
Andrea Favaretto (University of Padova, Italy), Renzo De Battisti (Corpo Forestale dello Stato, Padova, Italy), Gianni Pavan (University of Pavia, Italy) & Alberto Piccin (Corpo Forestale dello Stato, Vittorio Veneto, Italy)
During the rut in the years 2001-2002 in the Cansiglio Forest (NE Italy), more then 1300 vocalizations of red deer stags were recorded and analyzed. The acoustic analysis showed an evident spectrographic and temporal heterogeneity, so that we could classify them in 11 different classes. In particular, for the analyzed population, we found a clear distinction between three principal temporal classes, so we described the acoustic repertoire of the stags population during the considered rutting seasons.
The animal sound archive at the Humboldt-University of Berlin: Current activities in conservation and improving access for bioacoustic research
Karl-Heinz Frommolt (Humboldt-University of Berlin, Germany), Rolf Bardeli, Frank Kurth & Michael Clausen (University of Bonn, Germany)
The animal sound archive of the Humboldt-University is one of the oldest and largest collections of animal sounds. It was founded in 1951 by Günter Tembrock. Presently, the collection consists of about 120,000 bioacoustical recordings comprising almost all groups of animals. Most of the recordings are still on analogue magnetic tape. Currently, these tapes are transferred to digital storage media, mainly with 96 kHz sampling rate and 24 bit resolution. In this way, more than 50% of all recordings could already be preserved in digital form. The recordings will be documented by a database. Currently, an efficient system for the exchange of bioacoustical information, both metadata and soundfiles, for scientific purposes, is under development. The system consists of a central web-based database and local file storage servers. Free access to the metadata is available at "http://www.tierstimmen.org". Individual access to defined sound recordings will be controlled by password. The system should enable scientists to cooperate effectively in bioacoustic research.
Fonozoo.com a new resource in the web for the study of animal sounds
Gema Solís, Xavier Eekhout & Rafael Márquez Museo Nacional de Ciencias Naturales, Madrid, Spain)
We describe the functional structure of the Fonoteca Zoológica (FZ), a scientific collection of animal sounds in the National Natural Science Museum of Madrid. We present statistical data regarding the number of species with sounds in either the Published Sound Collection or the FZ Sound Collection. The Published Sound Collection includes commercially available sound guides published all over the world, and the FZ Sound Collection includes recordings made by researchers in the Museum and other collaborators. Comparisons in holdings are made between the different taxa, and we emphasize the use of bioacoustics for the study of animal behaviour. Finally, we introduce the recently created web page www.FonoZoo.com from where it is possible to access the database of the animal sounds kept in the Fonoteca Zoológica.
Acoustic website on European singing cicadas
Matija Gogala (Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia)
The song pattern and other song parameters like frequency and/or intensity modulation are in most cases the best characters for recognition and determination of singing cicada species. Very useful comparative papers and book chapters with descriptions of song patterns were published, but many times researchers working on faunistics and systematics of Cicadoidea would like to have also an auditory impression of song characteristics in addition to the oscillograms and spectrograms published elsewhere. This is the reason that we started to construct the web site where interested persons can play back or even download typical song samples of various species of singing cicadas. Till now we restricted our selection to the European species of singing cicadas. Every species is represented with the picture of live animal, a specimen from the collection, and habitat if available, oscillograms and spectrograms of the calling song and other acoustic signals. The references (partly also with downloadable PDF files) describing their song characteristics are listed as well. Song samples are playable as QuickTime movies and can be also downloaded. Till now 36 species are represented, in the coverpage also the contributors are introduced and in the English index page one can find a list of species and some general explanations about the graphs used to represent the songs. The following colleagues, working on bioacoustics of singing cicadas agreed to offer their recordings, illustrations and references: Michel Boulard, Matija Gogala, Andrej V. Popov, Stéphane Puissant, Jerôme Sueur, José Quartau with his team and Tomi Trilar.
Acoustic playback: Contributions to the study of animal communication in the last 13 years (1992-2004)
Xavier Eekhout, Gema Solís & Rafael Márquez (Museo Nacional de Ciencias Naturales, Madrid, Spain)
Two different databases of scientific publications (Zoological Record and MedLine) were studied in order to identify trends in the use of acoustic playback techniques in the last 13 years (1992-2004). The articles that mentioned the use of acoustic playbacks were classified into 5 subjective classes depending on their topic: Physics, Physiology, Descriptive Studies, Applied Studies and Ethology. Within the class Ethology five subclasses were considered: Learning, Predation, Social Structure, Sexual Selection and Territoriality. From each article we recorded the year of publication, the taxonomic group studied, the country of the research team and the language in which the article was written. We found that there has been an increase in the number of articles published which use acoustic playbacks especially in the class Ethology. The most commonly studied taxonomic group is birds, and although there are research teams from many countries, in number of articles research teams from the USA are clearly dominant.
Software tools for automatically detecting, measuring and classifying animal sounds
Raimund Specht (Avisoft Bioacoustics, Berlin, Germany)
Many bioacoustic investigations involve the analysis of large amounts of sound recordings. Reviewing these files manually is often both extremely time-consuming and subject to making mistakes that result from the monotony of that procedure. It is therefore desired to have tools that automate this process. Avisoft Bioacoustics has been working on software tools that accomplish this goal. There are several approaches that are suitable for various analysis requirements. This paper describes the currently available options.
Bird sound classification and recognition using wavelets
Arja Selin, Jari Turunen & Juha T. Tanttu (Tampere University of Technology, Pori, Finland)
In this paper a new method for automatic classification and recognition of bird sounds is presented. Our main idea is to study, how inharmonic and transient bird sounds can be recognized efficiently. The data consisted of sounds of eight bird species. Five species, the Mallard (Anas platyrhynchos), the Graylag Goose (Anser anser), the Corncrake (Crex crex), the River Warbler (Locustella fluviatilis), and the Magpie (Pica pica) have inharmonic sounds, whereas the remaining three reference species, the Quail (Coturnix coturnix), the Spotted Crake (Porzana porzana), and the Pygmy Owl (Glaucidium passerinum) have harmonic sounds. The wavelet analysis was selected due to its ability to preserve both frequency and temporal information, and its ability to analyse signals which contain discontinuities and sharp spikes. The feature vectors calculated with the proposed algorithm from the wavelet coefficients were used as the inputs of two neural networks, the self-organizing map (SOM) and the multilayer perceptron (MLP). The results were encouraging, for the unsupervised SOM network recognized 78% and the supervised MLP network 96% of the test sounds correctly.
De-noising aspects in the context of feature extraction in automated bird sound recognition
Jari Turunen, Arja Selin, Juha T. Tanttu & Tarmo Lipping (Tampere University of Technology, Pori, Finland)
In this paper we demonstrate the effects of noise reduction in wavelet based bird sound recognition. The nonharmonic bird sounds are difficult to separate from the background noise in order to maintain necessary features for identification. We tested three options: (i) no filtering, (ii) adaptive filter bank and (iii) lowpass Finite Impulse Response (FIR) filter. The following identification results were obtained (i) 95.1%,(ii) 96% and (iii) 100%.
Sound recording of vocal activity of animals inhabiting subtropical forest on Iriomote Island in the southern Ryukyus, Japan
Shinichi Watanabe (University of the Ryukyus, Okinawa, Japan) & Hiroki Kobayashi (The University of Tokyo, Tokyo, Japan)
We developed a system to monitor distribution and activity of animals in a forest ecosystem using sound recorders. The study was conducted at 14 sites along a river in Iriomote Island in the southern Ryukyus, Japan, from September 2004 to July 2005. Vocal activity of animals was continuously recorded for a specific interval with a weatherproof automatic recording system. From the recorded data, we identified calls of 38 species of mammals, birds, reptiles, amphibians, and insects. For each species, we compared vocal activity during study periods in order to investigate the migratory periods of several species of birds, and also breeding activities of birds, frogs, and Orthoptera. In addition, we studied daily vocal activity to investigate variation during the study period. This system allows long-term consecutive and simultaneous monitoring at multiple locations without man-power, which is a great advantage for cost-effective monitoring of regional biodiversity.
Acoustic behaviour in Malawian Cichlids (Pseudotropheus, Cichlidae): Potential cues for species recognition and intraspecific communication
Jose Miguel Simões, Ines Duarte, Paulo Jorge Fonseca (Universidade de Lisboa, Lisbon, Portugal), G. F. Turner (University of Hull, England) & M. Clara P. Amorim (I.S.P.A., Lisbon, Portugal)
Acoustic communication may play an important role in mate recognition systems among African cichlids and may contribute to the evolutionary processes involved in their rapid speciation. Sounds produced in early courtship (during quivering) by males of three closely related Malawi species of the Pseudotropheus zebra complex (Pseudotropheus zebra, P. callainos and P. 'zebra gold') were recorded and compared among species. In one species (P. zebra), sounds emitted during quivering were compared to sounds produced during later courtship behaviour, such as circle and lead-swim, and with sounds emitted during male-male and female-female interactions. The following acoustic parameters were measured: sound duration (ms), number of pulses per sound, initial and mean pulse periods (ms), and peak frequency of sounds (Hz). Differences in male courtship sounds were found among species. P. 'zebra gold' produced longer sounds with a higher number of pulses than P. callainos, and P. zebra males showed longer initial and mean pulse periods than the other two species. In P. zebra, male courtship, male agonistic and female agonistic sounds also differed significantly in some parameters. These results suggest that in the studied species acoustic signals could be used in species-specific recognition and potentially promote reproductive isolation, and in intraspecific communication.
Individuality in the mating call of the male Lusitanian Toadfish (Halobatrachus didactylus)
M. Clara P. Amorim & Raquel O. Vasconcelos (I.S.P.A., Lisbon, Portugal)
During the breeding season, male Lusitanian Toadfish emit a tonal advertisement call (the boatwhistle) from their nests to attract mates. Boatwhistles begin and end with a grunt-like phase (P1 and P3) and contain a longer tonal portion in between (P2). In this study we examined individuality in the Lusitanian Toadfish boatwhistles. Recordings (5-10 min) of 13 males were made in shallow waters in the Tagus estuary, Portugal. Ten sounds were analysed per male. Boatwhistles from different individuals could easily be distinguished by the human ear, and visually by differences in their spectra and shape of the temporal envelope. Acoustic features showed very little intra-individual variation (i.e. coefficient of variations ? 0.1), including boatwhistle duration, relative duration, number of pulses and pulse period of both P1 and P2, and the relative amplitude of P1 in relation to P2 (amplitude modulation). All acoustic variables differed significantly among individuals (Kruskal-Wallis: P<0.001). Discriminant function analysis assigned 95% of calls to the correct individuals, with boatwhistle duration, P2 relative duration and amplitude modulation being the most important variables in the model. Individuality of mating sounds is unusual among fish and could be potentially used in mate choice and in spacing out territorial males.
Cues to orientation of a caller to a listener in biphonic and non-biphonic close range contact calls in the Dhole (Cuon alpinus)
Ilya A. Volodin, Michael M. Nagaylik (Lomonosov Moscow State University, Moscow, Russia) & Elena V. Volodina (Moscow Zoo, Moscow, Russia)
Dholes produce two call types with wide frequency ranges, potentially providing cues to orientation of a caller to a listener because of different distribution for the higher and lower frequencies. One call type is biphonic (yapsqueak), the second one (yap) includes only one fundamental with its harmonics. Here we compare the abilities the biphonic and non-biphonic, but rich in harmonics call types to encode orientation of a caller to a listener. We recorded calls and movements from three male Dholes, running singly forward and back in their identical enclosures and subdivided the recorded calls into two groups: produced toward a microphone in sector ?45°, and produced away from a microphone in sector 135-225°. For each call, within 20.3 ms time segment taken in a call centre, we calculated the amplitude ratio of sum of amplitudes higher 5 kHz to sum of amplitudes lower 5 kHz. For the pooled sample of yaps and yap-squeaks, the amplitude ratio was significantly higher for "toward" than for "from" call group. For yaps and yap-squeaks separately the results were similar. Also, Dhole showed interindividual differences both in preference of a particular call type and in reliability of cues to orientation. Overall, both biphonic yap-squeaks and non-biphonic yaps bored cues to orientation. We discuss, that the increased occurrence of biphonic yap-squeaks in the Dhole may be conditioned by their additional function as individual markers, lacking in non-biphonic yaps.
The ocurrence of nonlinear vocal phenomena in frustration whines of the Domestic Dog (Canis familiaris)
Elena V. Volodina (Moscow Zoo, Moscow, Russia), Ilya A. Volodin (Lomonosov Moscow State University, Moscow, Russia) & Olga A. Filatova (Moscow Zoo, Moscow, Russia)
We analyzed quantitatively the occurrence of nonlinear vocal phenomena in whines of 9 Domestic Dogs of 6 breeds. The dogs produced whines in response to a frustration-provoking situation (impossibility to perform the desired action), designed with their owners. The whines could consist two fundamental frequencies – the low (f0) and the high (g0), that could occur both singly as separate vocalizations and together within the same vocalization. The f0 varied between individuals from 0.4 to 1.4 kHz and either lacked nonlinear phenomena or bored deterministic chaos, subharmonics or frequency jumps within the f0. The g0 varied between individuals from 3.1 to 11 kHz and also either lacked nonlinear phenomena or bored sidebands. The simultaneous occurrence of f0 and g0 within the same whine resulted in biphonation, whereas the f0 following g0 resulted in frequency jump between the fundamentals. We found, that in whines of our object dogs nonlinear phenomena occurred significantly more often within the f0 than within the g0, and significantly more rarely in whines consisting both f0 and g0 than in whines consisting f0 or g0 singly. The occurrence of nonlinear phenomena showed the noticeable interindividual variability. We discuss mechanisms for production of the f0 and g0 in the Domestic Dog. Also, we propose, that the strong variability in whines of Domestic Dogs has a function to attract attention of the dog owners in situation of frustration, when a dog can't cope with a problem. In this relation, the nonlinear phenomena may represent a mechanism, supporting the high unpredictable variability in the structure of whines.
Group and individual discriminability in monozygotic twins' infant cry: A pilot study
Daniela Lenti Boero (Università della Valle d'Aosta, Italy) & Francesca Rocca (Università degli Studi di Milano, Italy)
The aim of this study was to investigate the acoustic structure of groups of monozygotic twins, recorded both at term and at earlier developmental ages. Cries from three groups of monozygotic twins affected by severe prematurity, and two groups of monozygotic twins affected by moderate prematurity for a total of 13 infants were recorded. Results show that wails sampled from cries uttered by groups of monozygotic twins were ascribed to the correct group, both at early developmental age, and at term, and also that wails of single individual twins were ascribed to the proper individual within its group. Present results suggest that the fixed components of cry structure are most important in shaping the acoustic characteristics of the cry, but also that intrauterine experience might influence the temperamental characteristics of monozygotic twins.
© International Bioacoustics Society. Credits


It's not a smartphone, so it must be a dumbphone, right?
Inside this phone is an entire factory. It could be Gary, Indiana, in its heyday (but without the smokestacks). Mysterious shapes connect to other mysterious shapes. Not mysterious to you if you have some background in electronics, but definitely mysterious to me with my degree in English Literature. That's okay. Because I don't know what all these cute little things are, I can pretend they are far more interesting than perhaps is the reality. To me, they appear efficient, but that's because I can't recognize which ones are dead.
Alas, this phone suffered hard use. I banged on it with the receiver after hours of frustrating phone calls trying to get the auto club to rescue a motorist stranded in subzero weather. The phone never fully recovered from such ill-usage. Eventually, after a series of power outages that additionally outraged its systems, the phone silently declined to make or receive further calls. Mea culpa? Probably.
I'll be recycling these pieces shortly. Perhaps some day I'll try to learn what the guts of this phone are and do, or what I could have done to fix it, but it seems unlikely since landline phone technology is basically obsolete. This phone does not play video games. It doesn't do e-mail. It can't show me a weather map. On the other hand, it does not tell a spy where I am unless I plug it into a phone outlet and put in some batteries. And it does look purposeful. A tiny manufacturing plant all by itself, connecting me to the world along wires buried in the ground and then strung high in the air. How amazing.


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Greek Success Story: The latest Orwellian Turn of the Greek Crisis
English Greek Crisis Uncategorized YanisV 5041 Views 0 comment	May 22, 2013
Greece's Prime Minister recently flew to China, to woo Chinese investors. In his bid to be persuasive, he adopted a radical narrative: Greece is a Success Story. A country that almost perished in 2012 is now on the mend; on the road to stabilisation and growth; a wonderful opportunity, currently, for investors to pick up ultra cheap investments and to benefit from the forthcoming growth. How much of this is true, however?
Greek Prime Ministers and Finance Ministers have been upbeat for the past three catastrophic years. Mr Samaras' narrative is, therefore, neither here nor there per se. Indeed, one may credibly argue that it is his job to put on a brave face and to be upbeat, especially when in a country like China where he is struggling to beat up some investments for his suffering country. However, what makes the Greek Success Story (GSS) narrative interesting is that the international press and the money markets seem to concur.
Six reasons are bandied about in support of GSS:
Yields of Greek government bonds have collapsed from 30% to 8% while two of the three credit rating agencies have upgraded the Greek state's creditworthiness
The economy's rate of shrinkage is falling
Wages have fallen drastically giving a major boost to Greek competitiveness
The government has managed, through an impressive series of cutbacks and tax hikes, to deliver a small but nevertheless significant primary budget surplus
The Athens stock exchange has doubled in value over the past few months
Greece's banks are consolidating and are being recapitalised, with some help from international investors
Taken together, these six observations seem to support the GSS narrative. But do they? Let us look at them one at a time:
1. Yields of Greek government bonds have collapsed from 30% to 8% while two of the three credit rating agencies have upgraded the Greek state's creditworthiness
All this is true. But it is also ridiculously irrelevant. Greece does not issue bonds. It is well and truly excluded from money market financing. The last ten-year bonds it issued for the purposes of financing the state were before May 2010. Since then, it issued a whole pack of them in March of 2012 as part of the so-called PSI; the massive haircut of the existing government bonds (except the ones that the ECB had already purchased – see here). The newly minted 2012 bonds were used to swap for the older ones; the ones that were being haircut. Each older bond was replaced by a new one with a face value almost half that of the older bond it replaced.
Even then Greece's debt was unsustainable. So, last December we saw another haircut – that was euphimistically presented as a 'debt buyback'. Whatever the intricacies of that operation, the gist of it was that the Greek state borrowed €11 billion from the ESM (European Stability Mechanism) in order to buy back most of those fresh, PSI-era, bonds at… 35% of their face value. By the end of that second haircut, only 13% of Greece's debt remains in the form of government bonds in the hands of private sector investors. In summary, when the financial press talks about the 'yields of Greece's government bonds', they are referring to this ultra-thin market of bond relics.
Still, why are these few remaining Greek bonds appreciating in value (and their yields are falling)? The answer is as simple as it is depressing: Because the markets have worked out (quiet correctly) that, while Greece's public debt still remains unsustainable (despite the two haircuts in one year), the next time it is written down it will be the European taxpayer that gets hit – not the investors who still hold on to the few Greek government bonds left in the market. Put differently, when Europe re-visits the Greek debt issue, the headache from imposing another haircut on these privateers (who will threaten Greece with expensive hold-outs) will not be worthwhile given the meagre benefits in terms of debt reduction. Thus, markets expect that these bonds will be redeemed fully and Greece's debt to the European Union (but not the ECB or the IMF) will be haircut instead.
In summary, there are excellent reasons why the Greek government bonds remaining in the hands of private investors are appreciating in value while everyone knows that the Greek state remains hopelessly bankrupt.
2. The economy's rate of shrinkage is falling
When political prisoners go on hunger strike, during the first week they lose a considerable proportion of their body weight. As the weeks pass, the rate of diminution in their weight drops. On the week of their death, if they continue to the bitter end, the rate of shrinkage is at its lowest, as they is precious little fat and muscle to be lost. This is precisely what is happening to the Greek economy.
3. Wages have fallen drastically giving a major boost to Greek competitiveness and thus heralding an investment boom
Wages have fallen sharply and labour unit costs have followed suit. The question however is: Is this a reason for investors, Greek or foreign, to loosen up their purse-strings and go on an investment spree? That investors like to see wages fall, there is no doubt. But does this suffice? Most certainly not. There are only two reasons for investing in the productive sectors of a country like Greece presently: One is if you think that, in addition to the falling labour costs, there will be effective demand for the goods and services domestically. There is no reason to expect this for Greece any time in the foreseeable future, since both the private and the public sector are continuing to deleverage. (The fact that prices are hardly falling, at a time of collapsing wages, signals a precipitoys fall in domestic demand.) A second reason is to believe that goods and services can be produced in Greece (taking advantage of the falling costs) for the purposes of exporting them. There is very little scope for this either, since the rest of Europe is recessionary and, more importantly, excess capacity exists elsewhere so that, if there is a boost in demand outside of Greece, production can be cranked up at minimal start-up cost to cover it in countries like Germany and the Netherlands. The only exception to that is tourism in which it may make sense for smart investors to buy cheaply some boutique hotels or even resorts and take advantage of the collapse of Egypt's tourist industry in the context of the Eastern Mediterranean market. However, such investments will make next to no difference to Greece's macro-economy since the funds imported to purchase the properties are most likely to be exported immediately by the former owners and new investment/jobs will be negligible.
In summary, the Greek government's own statistical agency tells us that in 2012 investment fell by 20% from the already ridiculously low levels of fixed capital investment in 2011. Moreover, the government is predicting a further fall in investment in 2013. The investment boom that is talked about is, therefore, a figment of someone's imagination at best or a piece of vile propaganda more likely
4. The government has managed, through an impressive series of cutbacks and tax hikes, to deliver a small but nevertheless significant primary budget surplus
This is also true. The state has reneged on its obligations to cancer patients, school children, the elderly and the infirm, its own suppliers (who are owed billions for supplies and services delivered long ago), small businesses which receive VAT rebates with many months delay, etc. Now, all that would have been understandable if the government's task were to create, however brutally, a primary surplus in order to bolster its bargaining position with the troika, giving itself the opportunity to survive without the troika's loans during a period of tough negotiations. But the government is not interested in the slightest in playing tough with the troika. Only with its own people, trying to impress the troika with its ruthlessness within. Even though everyone knows that these primary surpluses, built on what I call 'blood money', cannot be the basis for Greece to repay its loans to the troika (requiring another write down of Greece's public debt), the Athens government is pretending it can repay everything in this manner. (See here for a recent example.)
In summary, the reported primary surpluses, built on blood money as they are, cannot be thought of seriously as a sign that Greece has returned to public debt sustainability.
5. The Athens stock exchange has doubled in value over the past few months
So it has, alongside all stock exchanges around the world who seem determined to 'go it alone'; to climb inexorable QE-fuelled heights in response to the news that the real economy is… faltering, stuttering, stumbling. In the case of Greece, there is of course another, important twofold element: Germany's decision (a) not to amputate Greece from the Eurozone and (b) not to allow a proper probe in Greece's banks (in fear of what it would show and of the potential knock on effect of such probes in the realm of Germany's own Bankruptocracy). These two 'signals' have caused Athens' stock exchange (which was almost annihilated last year) to double its value – to thelevel it had reache back in… 1995. The only genuine improvement, that adds to the rally, concerns three large monopolistic companies that have managed to regain access to international finance through a bond issue. This is of course due to (i) the removal of the immediate threat that their assets will be converted to drachmas and (ii) their monopolistic position in Greece, that guarantees them a profit stream.
In summary, the recent rise of Athens' stock exchange is utterly devoid of any signs regarding an improvement in Greece's economy.
6. Greece's banks are consolidating and are being recapitalised, with some help from international investors
This is the grossest and most monstrous of all hyperbolae regarding GSS. Greece's banks are huge black holes, the epitome of zombie-banks. They need at least €150 billion to be properly recapitalised but only €35 is available (after last December's 'debt buyback' operation ate into the recap fund to be provided by the ESM). In addition, Greece's bankers are jostling for position, pulling political strings and entering into unsavoury deals with our wider Cleptocracy, so as to remain in control of 'their' banks, at the expense of course of the banks' capacity to borrow and to lend. See here for a whiff of the coalescence of Bankruptocracy and Cleptocracy that delivers a banking system which acts as a dead weight on Greece's private and household sector, pushing Greece's social economy deeper and further into a mire.
In summary, Greece's banking sector remains a black hole that destroys any source of dynamism within the country's social economy. The recapitalisation will prove a certain failure while the consolidations are effected with the sole criterion of bolstering the social and economic power of certain 'bankers' who want to use it in order to extract rents from the rest of Greek society. To speak of Greece's banking sector as a source of 'good news' for Greece is to molest the truth and to insult the intelligence of Europe's taxpayers (who are providing Greece's bankers with the funds that allow them to 'pretend and extend' at the expense of Greece's economy).
For three years now, Greece's establishment regime is attempting to convince the world, and the Greek people, that all is well in the best of all possible worlds. The difference now is that the international press seems to be buying this propaganda. Speaking personally, I am tired of having to counter 'good news' stories with analyses like the above for four long years now. I wish I could also rejoice in the 'good news'. Alas, it remains our moral duty to knock down 'good news' stories the purpose of which is to propagate narratives the explicit purpse of which is to impede policy changes that may bring us genuinely good news.
Monetising the… ECB: The latest insult to be added to Greece's multiplying injuries
"Austerity vs. Growth – A False Dilemma?", OECD FORUM, 28th May


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Q: nextjs timer between each request of getStaticProps our app need to do around 37000 pages generation with an array generated by getStaticPath
the getStaticProps need to do a request on our api for build each page, but we have currently some timeout request.
Then, i will try to add a little timer in each request (i think about 0.1 second) but i didn't find anywhere a nextjs parameter to do this
Anyone allready do this?

A: Ok so for your case I think you should use getServerSideProps, you told that you need Dynamic SEO for each page and that is exactly what getServerSideProps id for, the idea is to render specific meta that depend on the data you get from your request, here is an example below:
    export const getServerSideProps = async (context) => {
  try {
    let { data } = await axios.get("YOUR_URL")
    return {
      props: {
        data,
      },
    }
  } catch (e) {
    console.log(e)
  }
}

And in your component
<Head>
      <link rel="canonical" href={canonicalUrl} />
      <title>{title}</title>
      <meta name="title" content={data.productTitle} />
      <meta name="description" content={data.description} />
      ...etc
    </Head>

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