human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Several instruments can be used to identify patients with an unfavourable course of low back pain in general practice . However , it is unclear which instrument is the predictor of outcome . AIM To compare the predictive performance ( that is , calibration and discrimination ) of risk estimation by GPs with assessment s using the Orebro Musculoskeletal Pain Screening Question naire , the Low Back Pain Perception Scale ( LBPPS ) , and a prediction rule developed for this purpose . DESIGN OF STUDY A prospect i ve cohort study with 1-year follow-up . SETTING General practice in The Netherl and s. METHOD The outcome ' unfavourable course of low back pain ' was defined as having no clinical ly important improvement at minimally 50 % of the measurements at 6 , 13 , 26 , and 52 weeks . Logistic regression analyses were used to study associations between potential predictors and outcome . RESULTS In total , 60 GPs recruited 314 patients to the study ( 16 patients were excluded from analysis due to missing data on the course of low back pain ) . Over a third of patients ( 112/298 ) showed an unfavourable course of low back pain on follow-up . Risk estimation by GPs , the Orebro question naire , the LBPPS , and the prediction rule had discriminative ability ( area under the curve ) of 0.59 ( 95 % CI [ confidence intervals ] = 0.52 to 0.66 ) ; 0.61 ( 95 % CI = 0.54 to 0.67 ) ; 0.59 ( 95 % CI = 0.52 to 0.66 ) ; and 0.75 ( 95 % CI = 0.69 to 0.81 ) respectively . The prediction rule included history of low back pain , self-perceived risk to develop chronic low back pain , no solicitous responses of the patient 's partner ( as reported by the patient ) , frequent walking at work , and ' pain catastrophising ' . CONCLUSION Although the prediction rule performed best with regard to calibration and discrimination , it needs to be externally vali date d. Risk estimation by GPs performs as well as other instruments and , at present , seems to be the best available option Objective : Mental health problems often affect functioning to such an extent that they result in sick leave . The worldwide reported prevalence of mental health problems in the working population is 10%–18 % . In developed countries , mental health problems are one of the main grounds for receiving disability benefits . In up to 90 % of cases the cause is stress-related , and health-care utilisation is mainly restricted to primary care . The aim of this study was to assess the effectiveness of our Minimal Intervention for Stress-related mental disorders with Sick leave ( MISS ) in primary care , which is intended to reduce sick leave and prevent chronicity of symptoms . Design : Cluster-r and omised controlled educational trial . Setting : Primary health-care practice s in the Amsterdam area , The Netherl and s. Participants : A total of 433 patients ( MISS n = 227 , usual care [ UC ] n = 206 ) with sick leave and self-reported elevated level of distress . Interventions : Forty-six primary care physicians were r and omised to either receive  training in the MISS or to provide UC . Eligible patients were screened by mail . Outcome Measures : The primary outcome measure was duration of sick leave until lasting full return to work . The secondary outcomes were levels of self-reported distress , depression , anxiety , and somatisation . Results : No superior effect of the MISS was found on duration of sick leave ( hazard ratio 1.06 , 95 % confidence interval 0.87–1.29 ) nor on severity of self-reported symptoms . Conclusions : We found no evidence that the MISS is more effective than UC in our study sample of distressed patients . Continuing research should focus on the potential beneficial effects of the MISS ; we need to investigate which elements of the intervention might be useful and which elements should be adjusted to make the MISS effective Study Design . R and omized controlled trial . Objectives . To investigate the effectiveness and costs of a mini-intervention , provided in addition to the usual care , and the incremental effect of a work site visit for patients with subacute disabling low back pain . Summary of Background Data . There is lack of data on cost-effectiveness of brief interventions for patients with prolonged low back pain . Methods . A total of 164 patients with subacute low back pain were r and omized to a  mini-intervention group ( A ) , a work site visit group ( B ) , or a usual care group ( C ) . Groups A ( n = 56 ) and B ( n = 51 ) underwent one assessment by a physician plus a physiotherapist . Group B received a work site visit in addition . Group C served as controls ( n = 57 ) and was treated in municipal primary health care . All patients received a leaflet on back pain . Pain , disability , specific and generic health-related quality of life , satisfaction with care , days on sick leave , and use and costs of health care consumption were measured at 3- , 6- , and 12-month follow-ups . Results . During follow-up , fewer subjects had daily pain in Groups A and B than in Group C ( Group A vs. Group C , P = 0.002 ; Group B vs. Group C , P = 0.030 ) . In Group A , pain was less bothersome ( Group A vs. Group C , P = 0.032 ) and interfered less with daily life ( Group A vs. Group C , P = 0.040 ) than among controls . Average days on sick leave were 19 in Group A , 28 in Group B , and 41 in Group C ( Group A vs. Group C , P = 0.019 ) . Treatment satisfaction was better in the intervention groups than among the controls , and costs were lowest in the mini-intervention group . Conclusions . Mini-intervention reduced daily back pain symptoms and sickness absence , improved adaptation to pain and patient satisfaction among patients with subacute low back pain , without increasing health care costs . A work site visit did not increase effectiveness Background . The IMPaCT Back study ( IMplementation to improve Patient Care through Targeted treatment for Back pain ) is a quality improvement study which aims to investigate the effects of introducing and supporting a subgrouping for targeted treatment system for patients with low back pain ( LBP ) in primary care . This paper details the subgrouping for targeted treatment system and the clinical training and mentoring programmes aim ed at equipping clinicians to deliver it . The subgrouping and targeted treatment system . This system differs from ‘ one-size fits all ’ usual practice as it suggests that first contact health care practitioners should systematic ally allocate LBP patients to one of the three subgroups according to key modifiable prognostic indicators for chronicity . Patients in each subgroup ( those at low , medium or high risk of chronicity ) are then managed according to a targeted treatment system of increasing complexity . The subgrouping tools . Subgrouping tools help guide clinical decision-making about treatment and onward referral . Two subgrouping tools have been used in the IMPaCT Back study , a 9-item version used by participating physiotherapists and a 6-item version used by GPs . The targeted treatments . The targeted treatments include a minimal intervention delivered by GPs ( for those patients at low risk of poor outcome ) or referral to primary care physiotherapists who can apply physiotherapy approaches to addressing pain and disability  ( for those at medium risk ) and additional cognitive-behavioural approaches to help address  psychological and social obstacles to recovery  ( for those at high risk ) . The training packages . Building on previous interventions for other pilot studies and r and omized trials , we have developed and delivered clinical training and support programmes for GPs and physiotherapists . Discussion . This paper describes in detail the IMPaCT Back study ’s subgrouping for targeted treatment system and the training and mentoring packages aim ed at equipping clinicians to deliver it , within the IMPaCT Back study . Study registration . IS RCT N55174281 BACKGROUND Medically unexplained physical symptoms present one of the most common problems in modern medical practice but often prove difficult to manage . The central position of the GP in the care of patients with medically unexplained symptoms has been emphasized repeatedly , but little is known about the attitudes of GPs to this role . Underst and ing how GPs view these patients may inform the development of effective strategies for management . OBJECTIVE Our aim was to survey the attitudes of UK GPs towards medically unexplained symptoms  ( MUS ) and somatization . METHODS A r and om sample of 400 GPs in the South Thames ( West ) region were surveyed using a postal question naire . Respondents ' attitudes toward the cause and management of MUS were recorded . RESULTS A total of 284 completed question naires were returned ( 22 returned incomplete ) , giving an adjusted response rate of 75 % . Although it was broadly felt that patients with MUS are difficult to manage , most GPs felt that patients with MUS should be managed in primary care . Providing reassurance , counselling and acting as a ' gatekeeper ' to prevent inappropriate investigations were considered important roles for GP management . A majority felt that patients with MUS have personality problems or psychiatric illness . Fewer than half of the respondents felt that there are effective treatments available for somatization . CONCLUSION GPs consider the management of patients with MUS to be an important part of their workload , but there is a perception that effective management strategies are lacking . Psychiatrists need to offer greater support and training for GPs in this area of health care Abstract Objective To compare the effects of a minimal intervention strategy aim ed at assessment and modification of psychosocial prognostic factors and usual care for treatment of (sub)acute low back pain in general practice . Design Cluster r and omised clinical trial . Setting 60 general practitioners in 41 general practice s. Participants 314 patients with non-specific low back pain of less than 12 weeks ' duration , recruited by their general practitioner . Interventions In the minimal intervention strategy group the general practitioner explored the presence of psychosocial prognostic factors , discussed these factors , set specific goals for reactivation , and provided an educational booklet . The consultation took about 20 minutes . Usual care was not st and ardised . Main outcome measures Functional disability ( Rol and -Morris disability question naire ) , perceived recovery , and sick leave because of low back pain assessed at baseline and after 6 , 13 , 26 , and 52 weeks . Results The dropout rate was 8 % in the minimal intervention strategy group and 9 % in the usual care group . Multilevel analyses showed no significant differences between the groups on any outcome measure during 12 months of follow-up in the whole group or in relevant subgroups ( patients with high scores on psychosocial measures at baseline or a history of frequent or prolonged low back pain ) . Conclusion This study provides no evidence that ( Dutch ) general practitioners should adopt our new treatment strategy aim ed at psychosocial prognostic factors in patients with (sub)acute low back pain . Further research should examine why our new strategy was not more effective than usual care Underst and ing the course of back pain is important for clinicians and research ers , but analyses of longitudinal data from multiple time points are lacking . A prospect i ve cohort study of consecutive back pain consulters from five general practice s in the United Kingdom was carried out between 2001 and 2003 to identify groups defined by their pain pathways . Patients were sent monthly question naires for a year . Longitudinal latent class analysis was performed by using pain intensity scores for 342 consulters . Analysis yielded four clusters representing different pathways of back pain . Cluster 1 ( " persistent mild " ; n = 122 ) patients had stable , low levels of pain . Patients in cluster 2 ( " recovering " ; n = 104 ) started with mild pain , progressing quickly to no pain . Cluster 3 ( " severe chronic " ; n = 71 ) patients had permanently high pain . For patients in cluster 4 ( " fluctuating " ; n = 45 ) , pain varied between mild and high levels . Distinctive patterns for each cluster were maintained throughout follow-up . Clusters showed statistically significant differences in disability , psychological status , and work absence ( p < 0.001 ) . This is the first time , to the authors ' knowledge , that latent class analysis has been applied to longitudinal data on back pain patients . Identification of four distinct groups of patients improves underst and ing of the course of back pain and may provide a basis of classification for intervention OBJECTIVE To describe a new tool design ed to capture patients ' perception of their low back pain ( LBP ) episodes-the  patient perception scale ( PPS ) and test its ability to predict episode outcomes . METHODS Thirty-two family physicians recruited 526 low back pain patients during an office visit . Physicians completed a short question naire at the index visit , which included both their assessment s of patients ' patient perception scale ( PPS-doc ) and contact information . Patients were then interviewed by telephone within 2 weeks after the index visit , with follow-up telephone contacts at 2 , 4 , 8 and 12 months . The  patient perception scale as reported by the physician ( PPS-doc ) and patient ( PPS-pt ) , each constituent question , and different combinations were analyzed for their ability to predict patient outcomes . RESULTS Patients ' responses ( PPS-pt ) proved predictive for all outcome items . PPS-doc was much less predictive . Measures of patient centeredness did not perform well in this study . CONCLUSION By using a short scale based on the patient 's perception of pain ( PPS-pt ) , it is possible to predict adverse outcomes of a low back pain episode . The patient perception scale should be evaluated further and perhaps combined with other instruments for targeting care and chronicity prevention efforts in low back pain . PRACTICE IMPLICATION S The PPS-pt could potentially be used as part of the st and ard initial patient evaluation of new LBP patients , as a proxy for " yellow flags " ( markers of psychosocial risk ) where a positive score might be the equivalent to high-risk identification . The apparent advantage of this scale is its brevity and simplicity of administration . The separation , through this 
    Output:
    
agent
In the first systematic review , the patients ' or HCPs ' overall judgment about the likely evolution of LBP was the factor most strongly linked to poor outcome , with predictive validity similar to that of multidimensional scales .
This result may be explained by the implicit aggregation of many prognostic factors underlying this judgment and suggests the relevance of considering the patients from biopsychosocial and longitudinal points of view .
It is unlikely that any intervention focusing on a single factor would ever fit the needs of most patients ; interventions targeting determinants from several fields ( mainly psychosocial , biomechanical , and occupational ) may be more relevant .
Finally , in the third study , the prevalence of psychosocial comorbidity in chronic LBP patients was not found to be significantly higher than in other patients consulting in primary care .
Rather than specifically screening for psychosocial conditions , this suggests taking into account any potential comorbidity in patients with chronic LBP , as in other patients .
As this condition is illustrative of many situations encountered in primary care , the strategies proposed here may benefit most patients consulting in this setting
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Several instruments can be used to identify patients with an unfavourable course of low back pain in general practice . However , it is unclear which instrument is the predictor of outcome . AIM To compare the predictive performance ( that is , calibration and discrimination ) of risk estimation by GPs with assessment s using the Orebro Musculoskeletal Pain Screening Question naire , the Low Back Pain Perception Scale ( LBPPS ) , and a prediction rule developed for this purpose . DESIGN OF STUDY A prospect i ve cohort study with 1-year follow-up . SETTING General practice in The Netherl and s. METHOD The outcome ' unfavourable course of low back pain ' was defined as having no clinical ly important improvement at minimally 50 % of the measurements at 6 , 13 , 26 , and 52 weeks . Logistic regression analyses were used to study associations between potential predictors and outcome . RESULTS In total , 60 GPs recruited 314 patients to the study ( 16 patients were excluded from analysis due to missing data on the course of low back pain ) . Over a third of patients ( 112/298 ) showed an unfavourable course of low back pain on follow-up . Risk estimation by GPs , the Orebro question naire , the LBPPS , and the prediction rule had discriminative ability ( area under the curve ) of 0.59 ( 95 % CI [ confidence intervals ] = 0.52 to 0.66 ) ; 0.61 ( 95 % CI = 0.54 to 0.67 ) ; 0.59 ( 95 % CI = 0.52 to 0.66 ) ; and 0.75 ( 95 % CI = 0.69 to 0.81 ) respectively . The prediction rule included history of low back pain , self-perceived risk to develop chronic low back pain , no solicitous responses of the patient 's partner ( as reported by the patient ) , frequent walking at work , and ' pain catastrophising ' . CONCLUSION Although the prediction rule performed best with regard to calibration and discrimination , it needs to be externally vali date d. Risk estimation by GPs performs as well as other instruments and , at present , seems to be the best available option Objective : Mental health problems often affect functioning to such an extent that they result in sick leave . The worldwide reported prevalence of mental health problems in the working population is 10%–18 % . In developed countries , mental health problems are one of the main grounds for receiving disability benefits . In up to 90 % of cases the cause is stress-related , and health-care utilisation is mainly restricted to primary care . The aim of this study was to assess the effectiveness of our Minimal Intervention for Stress-related mental disorders with Sick leave ( MISS ) in primary care , which is intended to reduce sick leave and prevent chronicity of symptoms . Design : Cluster-r and omised controlled educational trial . Setting : Primary health-care practice s in the Amsterdam area , The Netherl and s. Participants : A total of 433 patients ( MISS n = 227 , usual care [ UC ] n = 206 ) with sick leave and self-reported elevated level of distress . Interventions : Forty-six primary care physicians were r and omised to either receive  training in the MISS or to provide UC . Eligible patients were screened by mail . Outcome Measures : The primary outcome measure was duration of sick leave until lasting full return to work . The secondary outcomes were levels of self-reported distress , depression , anxiety , and somatisation . Results : No superior effect of the MISS was found on duration of sick leave ( hazard ratio 1.06 , 95 % confidence interval 0.87–1.29 ) nor on severity of self-reported symptoms . Conclusions : We found no evidence that the MISS is more effective than UC in our study sample of distressed patients . Continuing research should focus on the potential beneficial effects of the MISS ; we need to investigate which elements of the intervention might be useful and which elements should be adjusted to make the MISS effective Study Design . R and omized controlled trial . Objectives . To investigate the effectiveness and costs of a mini-intervention , provided in addition to the usual care , and the incremental effect of a work site visit for patients with subacute disabling low back pain . Summary of Background Data . There is lack of data on cost-effectiveness of brief interventions for patients with prolonged low back pain . Methods . A total of 164 patients with subacute low back pain were r and omized to a  mini-intervention group ( A ) , a work site visit group ( B ) , or a usual care group ( C ) . Groups A ( n = 56 ) and B ( n = 51 ) underwent one assessment by a physician plus a physiotherapist . Group B received a work site visit in addition . Group C served as controls ( n = 57 ) and was treated in municipal primary health care . All patients received a leaflet on back pain . Pain , disability , specific and generic health-related quality of life , satisfaction with care , days on sick leave , and use and costs of health care consumption were measured at 3- , 6- , and 12-month follow-ups . Results . During follow-up , fewer subjects had daily pain in Groups A and B than in Group C ( Group A vs. Group C , P = 0.002 ; Group B vs. Group C , P = 0.030 ) . In Group A , pain was less bothersome ( Group A vs. Group C , P = 0.032 ) and interfered less with daily life ( Group A vs. Group C , P = 0.040 ) than among controls . Average days on sick leave were 19 in Group A , 28 in Group B , and 41 in Group C ( Group A vs. Group C , P = 0.019 ) . Treatment satisfaction was better in the intervention groups than among the controls , and costs were lowest in the mini-intervention group . Conclusions . Mini-intervention reduced daily back pain symptoms and sickness absence , improved adaptation to pain and patient satisfaction among patients with subacute low back pain , without increasing health care costs . A work site visit did not increase effectiveness Background . The IMPaCT Back study ( IMplementation to improve Patient Care through Targeted treatment for Back pain ) is a quality improvement study which aims to investigate the effects of introducing and supporting a subgrouping for targeted treatment system for patients with low back pain ( LBP ) in primary care . This paper details the subgrouping for targeted treatment system and the clinical training and mentoring programmes aim ed at equipping clinicians to deliver it . The subgrouping and targeted treatment system . This system differs from ‘ one-size fits all ’ usual practice as it suggests that first contact health care practitioners should systematic ally allocate LBP patients to one of the three subgroups according to key modifiable prognostic indicators for chronicity . Patients in each subgroup ( those at low , medium or high risk of chronicity ) are then managed according to a targeted treatment system of increasing complexity . The subgrouping tools . Subgrouping tools help guide clinical decision-making about treatment and onward referral . Two subgrouping tools have been used in the IMPaCT Back study , a 9-item version used by participating physiotherapists and a 6-item version used by GPs . The targeted treatments . The targeted treatments include a minimal intervention delivered by GPs ( for those patients at low risk of poor outcome ) or referral to primary care physiotherapists who can apply physiotherapy approaches to addressing pain and disability  ( for those at medium risk ) and additional cognitive-behavioural approaches to help address  psychological and social obstacles to recovery  ( for those at high risk ) . The training packages . Building on previous interventions for other pilot studies and r and omized trials , we have developed and delivered clinical training and support programmes for GPs and physiotherapists . Discussion . This paper describes in detail the IMPaCT Back study ’s subgrouping for targeted treatment system and the training and mentoring packages aim ed at equipping clinicians to deliver it , within the IMPaCT Back study . Study registration . IS RCT N55174281 BACKGROUND Medically unexplained physical symptoms present one of the most common problems in modern medical practice but often prove difficult to manage . The central position of the GP in the care of patients with medically unexplained symptoms has been emphasized repeatedly , but little is known about the attitudes of GPs to this role . Underst and ing how GPs view these patients may inform the development of effective strategies for management . OBJECTIVE Our aim was to survey the attitudes of UK GPs towards medically unexplained symptoms  ( MUS ) and somatization . METHODS A r and om sample of 400 GPs in the South Thames ( West ) region were surveyed using a postal question naire . Respondents ' attitudes toward the cause and management of MUS were recorded . RESULTS A total of 284 completed question naires were returned ( 22 returned incomplete ) , giving an adjusted response rate of 75 % . Although it was broadly felt that patients with MUS are difficult to manage , most GPs felt that patients with MUS should be managed in primary care . Providing reassurance , counselling and acting as a ' gatekeeper ' to prevent inappropriate investigations were considered important roles for GP management . A majority felt that patients with MUS have personality problems or psychiatric illness . Fewer than half of the respondents felt that there are effective treatments available for somatization . CONCLUSION GPs consider the management of patients with MUS to be an important part of their workload , but there is a perception that effective management strategies are lacking . Psychiatrists need to offer greater support and training for GPs in this area of health care Abstract Objective To compare the effects of a minimal intervention strategy aim ed at assessment and modification of psychosocial prognostic factors and usual care for treatment of (sub)acute low back pain in general practice . Design Cluster r and omised clinical trial . Setting 60 general practitioners in 41 general practice s. Participants 314 patients with non-specific low back pain of less than 12 weeks ' duration , recruited by their general practitioner . Interventions In the minimal intervention strategy group the general practitioner explored the presence of psychosocial prognostic factors , discussed these factors , set specific goals for reactivation , and provided an educational booklet . The consultation took about 20 minutes . Usual care was not st and ardised . Main outcome measures Functional disability ( Rol and -Morris disability question naire ) , perceived recovery , and sick leave because of low back pain assessed at baseline and after 6 , 13 , 26 , and 52 weeks . Results The dropout rate was 8 % in the minimal intervention strategy group and 9 % in the usual care group . Multilevel analyses showed no significant differences between the groups on any outcome measure during 12 months of follow-up in the whole group or in relevant subgroups ( patients with high scores on psychosocial measures at baseline or a history of frequent or prolonged low back pain ) . Conclusion This study provides no evidence that ( Dutch ) general practitioners should adopt our new treatment strategy aim ed at psychosocial prognostic factors in patients with (sub)acute low back pain . Further research should examine why our new strategy was not more effective than usual care Underst and ing the course of back pain is important for clinicians and research ers , but analyses of longitudinal data from multiple time points are lacking . A prospect i ve cohort study of consecutive back pain consulters from five general practice s in the United Kingdom was carried out between 2001 and 2003 to identify groups defined by their pain pathways . Patients were sent monthly question naires for a year . Longitudinal latent class analysis was performed by using pain intensity scores for 342 consulters . Analysis yielded four clusters representing different pathways of back pain . Cluster 1 ( " persistent mild " ; n = 122 ) patients had stable , low levels of pain . Patients in cluster 2 ( " recovering " ; n = 104 ) started with mild pain , progressing quickly to no pain . Cluster 3 ( " severe chronic " ; n = 71 ) patients had permanently high pain . For patients in cluster 4 ( " fluctuating " ; n = 45 ) , pain varied between mild and high levels . Distinctive patterns for each cluster were maintained throughout follow-up . Clusters showed statistically significant differences in disability , psychological status , and work absence ( p < 0.001 ) . This is the first time , to the authors ' knowledge , that latent class analysis has been applied to longitudinal data on back pain patients . Identification of four distinct groups of patients improves underst and ing of the course of back pain and may provide a basis of classification for intervention OBJECTIVE To describe a new tool design ed to capture patients ' perception of their low back pain ( LBP ) episodes-the  patient perception scale ( PPS ) and test its ability to predict episode outcomes . METHODS Thirty-two family physicians recruited 526 low back pain patients during an office visit . Physicians completed a short question naire at the index visit , which included both their assessment s of patients ' patient perception scale ( PPS-doc ) and contact information . Patients were then interviewed by telephone within 2 weeks after the index visit , with follow-up telephone contacts at 2 , 4 , 8 and 12 months . The  patient perception scale as reported by the physician ( PPS-doc ) and patient ( PPS-pt ) , each constituent question , and different combinations were analyzed for their ability to predict patient outcomes . RESULTS Patients ' responses ( PPS-pt ) proved predictive for all outcome items . PPS-doc was much less predictive . Measures of patient centeredness did not perform well in this study . CONCLUSION By using a short scale based on the patient 's perception of pain ( PPS-pt ) , it is possible to predict adverse outcomes of a low back pain episode . The patient perception scale should be evaluated further and perhaps combined with other instruments for targeting care and chronicity prevention efforts in low back pain . PRACTICE IMPLICATION S The PPS-pt could potentially be used as part of the st and ard initial patient evaluation of new LBP patients , as a proxy for " yellow flags " ( markers of psychosocial risk ) where a positive score might be the equivalent to high-risk identification . The apparent advantage of this scale is its brevity and simplicity of administration . The separation , through this 
    Output:
    