Linear stability analysis of transverse dunes

Sand-moving winds blowing from a constant direction in an area of high sand availability form transverse dunes, which have a fixed profile in the direction orthogonal to the wind. Here we show, by means of a linear stability analysis, that transverse dunes are intrinsically unstable. Any along-axis perturbation on a transverse dune amplify in the course of dune migration due to the combined effect of two main factors, namely: the lateral transport through avalanches along the dune's slip-face, and the scaling of dune migration velocity with the inverse of the dune height. Our calculations provide a quantitative explanation for recent observations from experiments and numerical simulations, which showed that transverse dunes moving on the bedrock cannot exist in a stable form and decay into a chain of crescent-shaped barchans.Comment: 8 pages, 4 figure

Explaining primary health care pharmacy expenditure using classification of medications for chronic conditions

Background The Valencian Autonomous Community (Spain) has implemented a scheme of purchasing services with the participation of public and private providers. Five districts are managed using public¿private partnership. The financing model is capitation and inter-center invoice. The pharmaceutical benefits are not included in the per capita assignment. Objectives Modeling and explaining pharmacy expenditure using electronic prescriptions drug data. Methods A database of electronic prescription corresponding to 625,246 patients between November 2008 and October 2009 was used to run four linear models that explain the pharmaceutical expenditures. We take as dependent variable the neperian log of total pharmacy annual cost per patient in the primary health setting. The independent variables used combined demographics with revised classification in 18 chronic conditions obtained from the anatomical therapeutic chemical classification index (ATC). Results The retrospective model selected included: gender, pharmaceutical co-payment status and 8 dummy variables for the number of chronic conditions of each patient from 1 to 8 or more. The goodness-of-fit achieved is measured in R2 of 57%. Conclusions These models must be considered in the current capitation system for pharmaceutical budgeting in a primary care setting established at regional level, as is the case in the Valencian Autonomous Community. The use of diagnostics and information regarding hospital encounters appears to be a complementary option for refining models of capitation of pharmaceutical and total health expenditure.The authors thank the General Direction of Pharmacy of the Valencian Department of Health for financial support and the working group for providing the data set. The opinions expressed in this paper are those of the authors and do not necessarily reflect those of the afore-named. Any errors are the authors' responsibility. We would also like to thank the two anonymous reviewers for their comments, which helped greatly to improve this paper.Vivas Consuelo, DJJ.; Guadalajara Olmeda, MN.; Barrachina Martínez, I.; Trillo-Mata, J.; Usó-Talamantes, R.; De La Poza, E. (2011). Explaining primary health care pharmacy expenditure using classification of medications for chronic conditions. Health Policy. 103(1):9-15. https://doi.org/10.1016/j.healthpol.2011.08.014S915103

Reducing the global burden of cerebral venous thrombosis:An international research agenda

Background:Due to the rarity of cerebral venous thrombosis (CVT), performing high-quality scientific research in this field is challenging. Providing answers to unresolved research questions will improve prevention, diagnosis, and treatment, and ultimately translate to a better outcome of patients with CVT. We present an international research agenda, in which the most important research questions in the field of CVT are prioritized.Aims:This research agenda has three distinct goals: (1) to provide inspiration and focus to research on CVT for the coming years, (2) to reinforce international collaboration, and (3) to facilitate the acquisition of research funding.Summary of review:This international research agenda is the result of a research summit organized by the International Cerebral Venous Thrombosis Consortium in Amsterdam, the Netherlands, in June 2023. The summit brought together 45 participants from 15 countries including clinical researchers from various disciplines, patients who previously suffered from CVT, and delegates from industry and non-profit funding organizations. The research agenda is categorized into six pre-specified themes: (1) epidemiology and clinical features, (2) life after CVT, (3) neuroimaging and diagnosis, (4) pathophysiology, (5) medical treatment, and (6) endovascular treatment. For each theme, we present two to four research questions, followed by a brief substantiation per question. The research questions were prioritized by the participants of the summit through consensus discussion.Conclusions:This international research agenda provides an overview of the most burning research questions on CVT. Answering these questions will advance our understanding and management of CVT, which will ultimately lead to improved outcomes for CVT patients worldwide

Predictability of pharmaceutical spending in primary health services using Clinical Risk Groups

Background: Risk adjustment instruments applied to existing electronic health records and administrative datasets may contribute to monitoring the correct prescribing of medicines. Objective: We aim to test the suitability of the model based on the CRG system and obtain specific adjusted weights for determined health states through a predictive model of pharmaceutical expenditure in primary health care. Methods: A database of 261,054 population in one health district of an Eastern region of Spain was used. The predictive power of two models was compared. The first model (ATC-model) used nine dummy variables: sex and 8 groups from 1 to 8 or more chronic conditions while in the second model (CRG-model) we include sex and 8 dummy variables for health core statuses 2-9. Results: The two models achieved similar levels of explanation. However, the CRG system offers higher clinical significance and higher operational utility in a real context, as it offers richer and more updated information on patients. Conclusions: The potential of the CRG model developed compared to ATC codes lies in its capacity to stratify the population according to specific chronic conditions of the patients, allowing us to know the degree of severity of a patient or group of patients, predict their pharmaceutical cost and establish specific programmes for their treatment. (C) 2014 Elsevier Ireland Ltd. All rights reserved.This study was financed by a grant from the Fondo de Investigaciones de la Seguridad Social Instituto de Salud Carlos III, the Spanish Ministry of Health (FIS PI12/0037). The authors would like to thank members (Juan Bru and Inma Sauri) of the Pharmacoeconomics Office of the Valencian Health Agency. The opinions expressed in this paper are those of the authors and do not necessary reflect those of the afore-named. Any errors are the authors' responsibility. We would also like to thank John Wright for the English editing.Vivas Consuelo, DJJ.; Usó Talamantes, R.; Trillo Mata, JL.; Caballer Tarazona, M.; Barrachina Martínez, I.; Buigues Pastor, L. (2014). Predictability of pharmaceutical spending in primary health services using Clinical Risk Groups. Health Policy. 116(2-3):188-195. https://doi.org/10.1016/j.healthpol.2014.01.012S1881951162-

CITY AUTOMATED TRANSPORT SYSTEM (CATS): THE LEGACY OF AN INNOVATIVE EUROPEAN PROJECT

CATS is a collaborative European project promoting driverless vehicles that ended in December 2014. This contribution explains how the project evolved, including the handling of unexpected events and concentrating on lessons learned. The constructor and vehicle had to be changed for economic reasons in the middle of the project timeline. A second constructor went bankrupt, although access to his vehicles could be secured. For security and legal reasons, part of the final demonstration was relocated at short notice to the EPFL campus in Lausanne, Switzerland, where around 1600 people were transported during 16 days of vehicle operation. Reactions to the driverless vehicle concept were overwhelmingly positive. Implications for the acceptability of driverless vehicles in Europe and elsewhere are discussed

Pharmaceutical Cost Management in an Ambulatory Setting Using a Risk Adjustment Tool

© 2014 Vivas-Consuelo et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Background Pharmaceutical expenditure is undergoing very high growth, and accounts for 30% of overall healthcare expenditure in Spain. In this paper we present a prediction model for primary health care pharmaceutical expenditure based on Clinical Risk Groups (CRG), a system that classifies individuals into mutually exclusive categories and assigns each person to a severity level if s/he has a chronic health condition. This model may be used to draw up budgets and control health spending. Methods Descriptive study, cross-sectional. The study used a database of 4,700,000 population, with the following information: age, gender, assigned CRG group, chronic conditions and pharmaceutical expenditure. The predictive model for pharmaceutical expenditure was developed using CRG with 9 core groups and estimated by means of ordinary least squares (OLS). The weights obtained in the regression model were used to establish a case mix system to assign a prospective budget to health districts. Results The risk adjustment tool proved to have an acceptable level of prediction (R2 0.55) to explain pharmaceutical expenditure. Significant differences were observed between the predictive budget using the model developed and real spending in some health districts. For evaluation of pharmaceutical spending of pediatricians, other models have to be established. Conclusion The model is a valid tool to implement rational measures of cost containment in pharmaceutical expenditure, though it requires specific weights to adjust and forecast budgets.This study was financed by a grant from the Fondo de Investigaciones de la Seguridad Social Instituto de Salud Carlos III, the Spanish Ministry of Health (FIS PI12/0037). The authors would like to thank members (Juan Bru and Inma Saurf) of the Pharmacoeconomics Office of the Valencian Health Department. The opinions expressed in this paper are those of the authors and do not necessary reflect those of the afore-named. Any errors are the authors' responsibility. We would also like to thank John Wright for the English editing.Vivas Consuelo, DJJ.; Usó Talamantes, R.; Guadalajara Olmeda, MN.; Trillo Mata, JL.; Sancho Mestre, C.; Buigues Pastor, L. (2014). Pharmaceutical Cost Management in an Ambulatory Setting Using a Risk Adjustment Tool. 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Cerebral vein and dural sinus thrombosis in elderly patients

Backgound and Purpose - The clinical features and prognosis of cerebral vein and dural sinus thrombosis (CVT) in elderly patients have not been previously described. Methods - In a multicenter prospective observational study, we compared clinical and imaging features, risk factors, and outcome of adult patients aged = 65 years (elderly patients). Results - A total of 624 adult patients with CVT were registered and followed-up for a median of 16 months. Fifty-one (8.2%) were aged >= 65 years. Presentation as an isolated intracranial hypertension syndrome was less frequent in elderly patients (4/51 versus 139/573, P=0.008), whereas depressed consciousness (17 versus 97, P=0.005), and mental status changes (22 versus 115, P=0.001) were more frequent in the elderly. The prognosis of elderly patients was considerably worse than that of younger patients, as only 49% of elderly patients made a complete recovery (versus 82% in younger patients), whereas 27% died and 22% were dependent at the end of follow-up (versus 7 and 2% respectively in younger patients). Carcinoma (5 cases) was more frequent as a risk factor for CVT in elderly patients (P=0.017). During follow-up, elderly patients were more likely to experience thrombotic events (HR=4.8, 95% CI=1.9 to 11.9) and were less likely to experience severe headaches (HR=0.2, 95% CI=0.02, 0.97). Conclusions - Elderly patients with CVT have a distinctive clinical presentation: isolated intracranial hypertension is uncommon, whereas mental status and alertness disturbances are common. The prognosis of CVT is worse in elderly patient

Prognosis of cerebral vein and dural sinus thrombosis - Results of the International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT)

Background and Purpose - The natural history and long-term prognosis of cerebral vein and dural sinus thrombosis (CVT) have not been examined previously by adequately powered prospective studies. Methods - We performed a multinational ( 21 countries), multicenter ( 89 centers), prospective observational study. Patients were followed up at 6 months and yearly thereafter. Primary outcome was death or dependence as assessed by modified Rankin Scale ( mRS) score > 2 at the end of follow-up. Results - From May 1998 to May 2001, 624 adult patients with CVT were registered. At the end of follow-up ( median 16 months), 356 patients (57.1%) had no symptom or signs ( mRS = 0), 137 (22%) had minor residual symptoms ( mRS = 1), and 47 (7.5%) had mild impairments ( mRS = 2). Eighteen (2.9%) were moderately impaired ( mRS = 3), 14 (2.2%) were severely handicapped ( mRS = 4 or 5), and 52 (8.3%) had died. Multivariate predictors of death or dependence were age > 37 years ( hazard ratio [HR] = 2.0), male sex ( HR = 1.6), coma ( HR = 2.7), mental status disorder ( HR = 2.0), hemorrhage on admission CT scan ( HR = 1.9), thrombosis of the deep cerebral venous system ( HR = 2.9), central nervous system infection ( HR = 3.3), and cancer ( HR = 2.9). Fourteen patients ( 2.2%) had a recurrent sinus thrombosis, 27 (4.3%) had other thrombotic events, and 66 (10.6%) had seizures. Conclusions - The prognosis of CVT is better than reported previously. A subgroup (13%) of clinically identifiable CVT patients is at increased risk of bad outcome. These high-risk patients may benefit from more aggressive therapeutic interventions, to be studied in randomized clinical trial