Communication and optimal hierarchical networks

We study a general and simple model for communication processes. In the model, agents in a network (in particular, an organization) interchange information packets following simple rules that take into account the limited capability of the agents to deal with packets and the cost associated to the existence of open communication channels. Due to the limitation in the capability, the network collapses under certain conditions. We focus on when the collapse occurs for hierarchical networks and also on the influence of the flatness or steepness of the structure. We find that the need for hierarchy is related to the existence of costly connections.Comment: 7 pages, 2 figures. NATO ARW on Econophysic

General Practitioners' Attitudes towards Essential Competencies in End-of-Life Care: A Cross-Sectional Survey.

Identifying essential competencies in end-of-life care, as well as general practitioners' (GPs) confidence in these competencies, is essential to guide training and quality improvement efforts in this domain. To determine which competencies in end-of-life care are considered important by GPs, to assess GPs' confidence in these competencies in a European context and their reasons to refer terminally ill patients to a specialist. Cross-sectional postal survey involving a stratified random sample of 2000 GPs in Switzerland in 2014. Survey development was informed by a previous qualitative exploration of relevant end-of-life GP competencies. Main outcome measures were GPs' assessment of the importance of and confidence in 18 attributes of end-of-life care competencies, and reasons for transferring care of terminally-ill patients to a specialist. GP characteristics associated with main outcome measures were tested using multivariate regression models. The response rate was 31%. Ninety-nine percent of GPs considered the recognition and treatment of pain as important, 86% felt confident about it. Few GPs felt confident in cultural (16%), spiritual (38%) and legal end-of-life competencies such as responding to patients seeking assisted suicide (35%) although more than half of the respondents regarded these competencies as important. Most frequent reasons to refer terminally ill patients to a specialist were lack of time (30%), better training of specialists (23%) and end-of-life care being incompatible with other duties (19%). In multiple regression analyses, confidence in end-of-life care was positively associated with GPs' age, practice size, home visits and palliative training. GPs considered non-somatic competencies (such as spiritual, cultural, ethical and legal aspects) nearly as important as pain and symptom control. Yet, few GPs felt confident in these non-somatic competencies. These findings should inform training and quality improvement efforts in this domain, in particular for younger, less experienced GPs

Risk Factors for Recurrent Exacerbations in the General-Practitioner-Based Swiss Chronic Obstructive Pulmonary Disease (COPD) Cohort.

BACKGROUND Patients with chronic obstructive pulmonary disease (COPD) often suffer from acute exacerbations. Our objective was to describe recurrent exacerbations in a GP-based Swiss COPD cohort and develop a statistical model for predicting exacerbation. METHODS COPD cohort demographic and medical data were recorded for 24 months, by means of a questionnaire-based COPD cohort. The data were split into training (75%) and validation (25%) datasets. A negative binomial regression model was developed using the training dataset to predict the exacerbation rate within 1 year. An exacerbation prediction model was developed, and its overall performance was validated. A nomogram was created to facilitate the clinical use of the model. RESULTS Of the 229 COPD patients analyzed, 77% of the patients did not experience exacerbation during the follow-up. The best subset in the training dataset revealed that lower forced expiratory volume, high scores on the MRC dyspnea scale, exacerbation history, and being on a combination therapy of LABA + ICS (long-acting beta-agonists + Inhaled Corticosteroids) or LAMA + LABA (Long-acting muscarinic receptor antagonists + long-acting beta-agonists) at baseline were associated with a higher rate of exacerbation. When validated, the area-under-curve (AUC) value was 0.75 for one or more exacerbations. The calibration was accurate (0.34 predicted exacerbations vs 0.28 observed exacerbations). CONCLUSION Nomograms built from these models can assist clinicians in the decision-making process of COPD care

Intermediate care in caring for dementia, the point of view of general practitioners: A key informant survey across Europe.

Background: Intermediate care is often defined as healthcare occurring somewhere between traditional primary (community) and secondary (hospital) care settings. High quality intermediate care is important in dementia, may prevent caregiver burnout and also lead to optimal care for people with dementia. However, very little is known about the point of intermediate care for persons with dementia in Europe. Research questions: What intermediate care services exist and how are they utilized in the care of people with dementia in Europe? Objective: This study aims at describing the point of view of General Practitioners on intermediate care services for people with dementia across Europe. Methods: Key informant survey was sent to GPs via a self-developed questionnaire with space for open ended comments. 16 European countries participated to this cross-sectional mixed method study. Given the volunteer nature of the study, no minimum sample size requirements were applied to participation. Convenience sampling technique was used to address variations due to regional variations and regulations within the same country. Descriptive analyses of all intermediate care facilities groups by countries were performed. Qualitative analyses approach was used for the optional-free text to exemplify and/or complete the reasons contained in the closed response categories. Results: The questionnaire was sent to 16 European countries. 583 questionnaires were analyzed. The responding physicians were 48 (± 11) years old on average and they had been in practice for an average of 18 (+ /11) years. The types of intermediate care considered were integrated at-home services, respite and relief services, day care centers and nursing homes. Their availability was considered very inhomogeneous by the majority of respondents. The main benefits of intermediate care cited were better medical care for the patient (78%), better quality of life for the caregiver (67%), prevention of the caregiver burden (73%) and a break for the caregiver (59%). The reported difficulties were: accessing these facilities due to limited financial support (76%) and cumbersome administrative procedures (67%). Many other facets of our findings were captured in the qualitative themes that emerged. Conclusion: Intermediate care in Europe is diverse and heterogeneous. Major concerns of GPs are about the cost issues and the cumbersome administrative procedures to access them

Prevalence and characteristics of meticillin-resistant Staphylococcus aureus in humans in contact with farm animals, in livestock, and in food of animal origin, Switzerland, 2009

A total of 2,662 samples, collected from March to September 2009 in Switzerland, were tested for the presence of meticillin-resistant Staphylococcus aureus (MRSA). The collection comprised nasal swabs from 148 pig farmers, 133 veterinarians, 179 slaughterhouse employees, 800 pigs, 300 calves, 400 cattle, 100 pooled neck skin swabs from chicken carcasses, and 460 food samples of animal origin. Moreover, 142 S. aureus strains, isolated from bovine mastitis milk, were included in the study. Twenty samples (< 1%; four veterinarians, 10 pigs, three calves, one young bull, and two mastitis milk samples) tested positive for MRSA. Genotyping of the MRSA strains was performed by multilocus sequence typing, spa- and SCCmec-typing, and revealed ST398 (n=18), ST8 (n=1), ST 1 (n=1), spa types t011 (n=7), t034 (n=11), t064 (n=1), t127 (n=1), and SCCmec types IV (n=4) and V (n=16). The 20 MRSA strains were subjected to antibiotic susceptibility testing and pulsed-field gel electrophoresis using the restriction enzyme EagI. Supplementary PCR reactions were performed to investigate the presence of Panton-Valentine leukocidin and staphylococcal enterotoxins A to D

Systemic and local effects of disportional longitudinal growth of bones in foals and lambs and the impact on bone mineral density and content

In the present study the effects of „periosteal stripping“ on bone and cartilage metabolism of foals with angular limb deformities and healthy experimental lambs were examined. Five foals with angular limb deformities were treated surgically by means of „hemicircumferential transection of the periosteum and periosteal stripping“ (HCTP/HP). Before surgery as well as twice after surgery, 1,25(OH)2Vitamin D, bone and cartilage markers in the serum were determined and compared to 5 healthy foals of the same age. In addition 10 healthy lambs were treated by HCTP/HP, in which the same parameters and bone density were determined. At 22 days after surgery the lambs were sacrificed and treated and control bones were sampled and processed for immunohistochemistry. Neither in foals nor in lambs, significant differences could be observed between treated and untreated animals with regard to the parameters measured in serum. Nevertheless, both treated groups revealed a tendency for higher bone remodelling compared to control animals. This could be the result of an increased bone remodelling rate following surgery. No statistically significant difference in bone mineral density between treated and untreated animals could be detected. In contrast local changes of signal transduction related to parathyroid hormone related protein and indian hedgehog (PTHrP/Ihh) were observed using immunhistochemistry. It was concluded that HCTP/HP at the level of epiphysis and metaphysis does not lead to systemic effects, even though local events detected by immunohistochemistry point to an increased bone formation at the treated site

Phenotypic and molecular typing of Listeria monocytogenes isolated from the processing environment and products of a sandwich-producing plant

Listeria monocytogenes as a food-borne pathogen has significant public health and economic impacts. The present study investigated the diversity of L. monocytogenes in a Swiss sandwich-producing plant over a 12-months period. L. monocytogenes were detected by culture after enrichment in 70 (3.5%) of 2028 environmental swabs and 16 (7.4%) of 217 samples from ingredients and sandwiches. Of the 86 L. monocytogenes strains, 93% belonged to serotype 1/2a and genetic lineage II. Rep PCR and PFGE analysis yielded each six profiles. Sixty-seven (77.9%) strains belonged to only one genotype, which was repeatedly found on/in slicers, conveyor belts, tables, a bread-feeding machine, spattles, air blow-guns, salmon, and egg sandwiches. Strains of this genotype persisted for more than 9 months in the processing environment, in particular on slicers and conveyor belts, which probably contributed to the contamination of sandwiches. After revision of the cleaning and disinfection procedures, L. monocytogenes were no longer found on slicers, conveyor belts, or in products. Besides, these results emphasize the importance of environmental monitoring schemes to identify potential contamination sources and as an early warning system for food business operators