Stability and convergence in discrete convex monotone dynamical systems

We study the stable behaviour of discrete dynamical systems where the map is convex and monotone with respect to the standard positive cone. The notion of tangential stability for fixed points and periodic points is introduced, which is weaker than Lyapunov stability. Among others we show that the set of tangentially stable fixed points is isomorphic to a convex inf-semilattice, and a criterion is given for the existence of a unique tangentially stable fixed point. We also show that periods of tangentially stable periodic points are orders of permutations on $n$ letters, where $n$ is the dimension of the underlying space, and a sufficient condition for global convergence to periodic orbits is presented.Comment: 36 pages, 1 fugur

Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People

The European Working Group on Sarcopenia in Older People (EWGSOP) developed a practical clinical definition and consensus diagnostic criteria for age-related sarcopenia. EWGSOP included representatives from four participant organisations, i.e. the European Geriatric Medicine Society, the European Society for Clinical Nutrition and Metabolism, the International Association of Gerontology and Geriatrics—European Region and the International Association of Nutrition and Aging. These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: (i) What is sarcopenia? (ii) What parameters define sarcopenia? (iii) What variables reflect these parameters, and what measurement tools and cut-off points can be used? (iv) How does sarcopenia relate to cachexia, frailty and sarcopenic obesity? For the diagnosis of sarcopenia, EWGSOP recommends using the presence of both low muscle mass + low muscle function (strength or performance). EWGSOP variously applies these characteristics to further define conceptual stages as ‘presarcopenia', ‘sarcopenia' and ‘severe sarcopenia'. EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance. Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatmen

ESPEN Guideline: clinical nutrition in inflammatory bowel disease

Crohn’s disease; Ulcerative colitis; Nutritional therapyMalaltia de Crohn; Colitis ulcerosa; Teràpia nutricionalEnfermedad de Crohn; Colitis ulcerosa; Terapia nutricionalIntroduction: the ESPEN Guideline offers a multidisciplinary focus on clinical nutrition in inflammatory bowel disease (IBD). Methodology: the guideline is based on a extensive systematic review of the literature, but relies on expert opinion when objective data are lacking or inconclusive. The conclusions and 64 recommendations have been subject to full peer review and a Delphi process, in which uniformly positive responses (agree or strongly agree) were required. Results: IBD is increasingly common and potential dietary factors in its etiology are briefly reviewed. Malnutrition is highly prevalent in IBD — especially in Crohn’s disease. Increased energy and protein requirements are observed in some patients. The management of malnutrition in IBD is considered within the general context of support for malnourished patients. Treatment of iron deficiency (parenterally, if necessary) is strongly recommended. Routine provision of a special diet in IBD is not, however, supported. Parenteral nutrition is indicated only when enteral nutrition has failed or is impossible. The recommended perioperative management of patients with IBD undergoing surgery accords with general ESPEN guidance for patients having abdominal surgery. Probiotics may be helpful in UC but not in Crohn’s disease. Primary therapy using nutrition to treat IBD is not supported in ulcerative colitis but is moderately well supported in Crohn’s disease, especially in children, where the adverse consequences of steroid therapy are proportionally greater. However, exclusion diets are generally not recommended and there is little evidence to support any particular formula feed when nutritional regimens are constructed. Conclusions: available objective data to guide nutritional support and primary nutritional therapy in IBD are presented as 64 recommendations, of which 9 are very strong recommendations (grade A), 22 are strong recommendations (grade B), and 12 are based only on sparse evidence (grade 0); 21 recommendations are good practice points (GPP).Introducción: la guía ESPEN ofrece un enfoque multidisciplinar de la nutrición clínica en la enfermedad inflamatoria intestinal (EII). Metodología: la guía se basa en una extensa revisión sistemática de la literatura y en la opinión de expertos cuando faltan datos objetivos o estos no son concluyentes. Las conclusiones y las 64 recomendaciones han sido objeto de una revisión completa por pares y de un proceso Delphi en el que se requerían respuestas fuertemente positivas (de acuerdo o totalmente de acuerdo). Resultados: la EII es cada vez más común y se revisan brevemente los posibles factores dietéticos en su etiología. La desnutrición es muy prevalente en la EII, especialmente en la enfermedad de Crohn. En algunos pacientes se observan mayores requerimientos de energía y proteínas. El manejo de la desnutrición en la EII se considera dentro del contexto general de apoyo a los pacientes desnutridos. Se recomienda fuertemente el tratamiento de la deficiencia de hierro (por vía parenteral, si es necesario). Sin embargo, no se aconseja la prescripción de rutina de una dieta especial en la EII. La nutrición parenteral está indicada solo cuando la nutrición enteral ha fallado o es imposible. El manejo perioperatorio recomendado de los pacientes con EII sometidos a cirugía se hace de acuerdo con la guía general de la ESPEN para pacientes sometidos a cirugía abdominal. Los probióticos pueden ser útiles en la CU pero no en la enfermedad de Crohn. El tratamiento primario con nutrición para tratar la EII no está respaldado en la colitis ulcerosa, aunque está moderadamente bien soportado en la enfermedad de Crohn, especialmente en los niños, donde las consecuencias adversas de la terapia con esteroides son proporcionalmente mayores. Sin embargo, las dietas de exclusión generalmente no se recomiendan y hay poca evidencia que respalde cualquier fórmula de nutrición en particular cuando se realizan regímenes nutricionales. Conclusiones: los datos objetivos disponibles para guiar el apoyo nutricional y la terapia nutricional primaria en la EII se presentan como 64 recomendaciones, de las cuales 9 son recomendaciones muy fuertes (grado A), 22 son recomendaciones fuertes (grado B) y 12 se basan solo en evidencia escasa (grado 0); 21 recomendaciones son recomendaciones de buenas prácticas (GPP).El proceso de la guía ha sido financiado exclusivamente por la ESPEN

ESPEN guideline on nutritional support for polymorbid medical inpatients.

BACKGROUND Disease-related malnutrition in polymorbid medical inpatients is a highly prevalent syndrome associated with significantly increased morbidity, disability, short- and long-term mortality, impaired recovery from illness, and cost of care. AIM As there are uncertainties in applying disease-specific guidelines to patients with multiple conditions, our aim was to provide evidence-based recommendations on nutritional support for the polymorbid patient population hospitalized in medical wards. METHODS This update adheres to the standard operating procedures for ESPEN guidelines. We did a systematic literature search for 15 clinical questions in three different databases (Medline, Embase and the Cochrane Library), as well as in secondary sources (e.g. published guidelines), until July 12th. Retrieved abstracts were screened to identify relevant studies that were used to develop recommendations (incl. SIGN grading), which was followed by submission to Delphi voting. RESULTS From a total of 3527 retrieved abstracts, 60 new relevant studies were analyzed and used to generate a guideline draft that proposed 32 recommendations (7x A, 11x B, 10x O and 4x GPP), which encompass different aspects of nutritional support including indication, route of feeding, energy and protein requirements, micronutrient requirements, disease-specific nutrients, timing, monitoring and procedure of intervention. The results of the first online voting showed a strong consensus (agreement of >90%) on 100% of the recommendations. Therefore, no final consensus conference was needed. CONCLUSIONS Recent high-quality trials have provided increasing evidence that nutritional support can reduce morbidity and other complications associated with malnutrition in polymorbid patients. The timely screening of patients for risk of malnutrition at hospital admission followed by individualized nutritional support interventions for at-risk patients should be part of routine clinical care and multimodal treatment in hospitals worldwide. Use of this updated guideline offers an evidence-based nutritional approach to the polymorbid medical inpatients and may improve their outcomes

Biodiversity patterns of Arctic diatom assemblages in lakes and streams : Current reference conditions and historical context for biomonitoring

1. Comprehensive assessments of contemporary diatom distributions across the Arctic remain scarce. Furthermore, studies tracking species compositional differences across space and time, as well as diatom responses to climate warming, are mainly limited to paleolimnological studies due to a lack of routine monitoring in lakes and streams across vast areas of the Arctic. 2. The study aims to provide a spatial assessment of contemporary species distributions across the circum-Arctic, establish contemporary biodiversity patterns of diatom assemblages to use as reference conditions for future biomonitoring assessments, and determine pre-industrial baseline conditions to provide historical context for modern diatom distributions. 3. Diatom assemblages were assessed using information from ongoing regulatory monitoring programmes, individual research projects, and from surface sediment layers obtained from lake cores. Pre-industrial baseline conditions as well as the nature, direction and magnitude of changes in diatom assemblages over the past c.200 years were determined by comparing surface sediment samples (i.e. containing modern assemblages) with a sediment interval deposited prior to the onset of significant anthropogenic activities (i.e. containing pre-1850 assemblages), together with an examination of diatoms preserved in contiguous samples from dated sediment cores. 4. We identified several biotypes with distinct diatom assemblages using contemporary diatom data from both lakes and streams, including a biotype typical for High Arctic regions. Differences in diatom assemblage composition across circum-Arctic regions were gradual rather than abrupt. Species richness was lowest in High Arctic regions compared to Low Arctic and sub-Arctic regions, and higher in lakes than in streams. Dominant diatom taxa were not endemic to the Arctic. Species richness in both lakes and streams reached maximum values between 60°N and 75°N but was highly variable, probably reflecting differences in local and regional environmental factors and possibly sampling effort. 5. We found clear taxon-specific differences between contemporary and pre-industrial samples that were often specific to both ecozone and lake depth. Regional patterns of species turnover (β-diversity) in the past c.200 years revealed that regions of the Canadian High Arctic and the Hudson Bay Lowlands to the south showed most compositional change, whereas the easternmost regions of the Canadian Arctic changed least. As shown in previous Arctic diatom studies, global warming has already affected these remote high latitude ecosystems. 6. Our results provide reference conditions for future environmental monitoring programmes in the Arctic. Furthermore, diatom taxa identification and harmonisation require improvement, starting with circum-Arctic intercalibrations. Despite the challenges posed by the remoteness of the Arctic, our study shows the need for routine monitoring programmes that have a wide geographical coverage for both streams and lakes

GREAT3 results - I. Systematic errors in shear estimation and the impact of real galaxy morphology

We present first results from the third GRavitational lEnsing Accuracy Testing (GREAT3) challenge, the third in a sequence of challenges for testing methods of inferring weak gravitational lensing shear distortions from simulated galaxy images. GREAT3 was divided into experiments to test three specific questions, and included simulated space- and ground-based data with constant or cosmologically varying shear fields. The simplest (control) experiment included parametric galaxies with a realistic distribution of signal-to-noise, size, and ellipticity, and a complex point spread function (PSF). The other experiments tested the additional impact of realistic galaxy morphology, multiple exposure imaging, and the uncertainty about a spatially varying PSF; the last two questions will be explored in Paper II. The 24 participating teams competed to estimate lensing shears to within systematic error tolerances for upcoming Stage-IV dark energy surveys, making 1525 submissions overall. GREAT3 saw considerable variety and innovation in the types of methods applied. Several teams now meet or exceed the targets in many of the tests conducted (to within the statistical errors). We conclude that the presence of realistic galaxy morphology in simulations changes shear calibration biases by ∼1percent for a wide range of methods. Other effects such as truncation biases due to finite galaxy postage stamps, and the impact of galaxy type as measured by the Sérsic index, are quantified for the first time. Our results generalize previous studies regarding sensitivities to galaxy size and signal-to-noise, and to PSF properties such as seeing and defocus. Almost all methods' results support the simple model in which additive shear biases depend linearly on PSF ellipticit