A stochastic programming approach for dynamic allocation of bed capacity and assignment of patients to collaborating hospitals during pandemic outbreaks

We consider a region containing several hospitals collaborating to treat patients during an infectious outbreak. Collaboration occurs through the dynamic allocation of hospital bed capacity to infectious patients and by assigning infectious patients to specific hospitals. Scaling up capacity for infectious patients means that beds are removed from regular care, which can only be done simultaneously for all beds in a room. Moreover, as opening rooms for infectious patients takes some lead time, we have to decide on preparing to open rooms for infectious patients ahead of time. We apply a stochastic direct lookahead approach. Each day, we make decisions on room allocation and patient assignment based on the solutions of two stochastic programs with scenarios using short-time forecasts of the number of infectious hospitalizations in the region and the bed occupancy in each collaborating hospital. We aim to balance costs for bed shortages and unutilized beds for infectious patients and opening and closing rooms. We demonstrate that a stochastic lookahead is superior to a deterministic one. We furthermore compare our solution approach with two heuristic strategies in a simulation study based on historical COVID-19 data of a region with three hospitals in the Netherlands. In one strategy, hospitals decide on their capacity allocation individually. In another strategy, we assume a pandemic unit, where one hospital is designated to take all regional infectious patients until full. The numerical results show that our stochastic direct lookahead approach considerably outperforms these heuristics

Differences in Effects of Pyrrolizidine Alkaloids on Five Generalist Insect Herbivore Species

The evolution of the diversity in plant secondary compounds is often thought to be driven by insect herbivores, although there is little empirical evidence for this assumption. To investigate whether generalist insect herbivores could play a role in the evolution of the diversity of related compounds, we examined if (1) related compounds differ in their effects on generalists, (2) there is a synergistic effect among compounds, and (3) effects of related compounds differed among insect species. The effects of pyrrolizidine alkaloids (PAs) were tested on five generalist insect herbivore species of several genera using artificial diets or neutral substrates to which PAs were added. We found evidence that structurally related PAs differed in their effects to the thrips Frankliniella occidentalis, the aphid Myzus persicae, and the locust Locusta migratoria. The individual PAs had no effect on Spodoptera exigua and Mamestra brassicae caterpillars. For S. exigua, we found indications for synergistic deterrent effects of PAs in PA mixtures. The relative effects of PAs differed between insect species. The PA senkirkine had the strongest effect on the thrips, but had no effect at all on the aphids. Our results show that generalist herbivores could potentially play a role in the evolution and maintenance of the diversity of PA

Behavioral dominance between female color morphs of a Lake Victoria cichlid fish

Species that exhibit genetic color polymorphism are suitable for studying the evolutionary forces that maintain heritable phenotypic variation in nature. Male color morphs often differ in behavioral dominance, affecting the evolution of color polymorphisms. However, behavioral dominance among female color morphs has received far less attention. We studied a polymorphic population of the cichlid fish Neochromis omnicaeruleus from Lake Victoria, in which 3 distinct female color morphs coexist, black-and-white blotched (WB), orange blotched (OB), and plain (P) color morphs. First, we investigated dominance relationships among female morphs using triadic and dyadic encounters in the laboratory. In triadic encounters, both WB and OB females dominated plain, whereas WB females dominated OB females. Dominance of WB over OB was confirmed using dyadic encounters. In a second experiment, blotched (WB or OB) and plain full-sib sisters were bred by crossing a blotched and a plain parent. In dyadic encounters, WB female morphs dominated their plain sisters, suggesting that dominance of WB females is a pleiotropic effect of color or that genes coding for color and those influencing behavioral dominance are genetically linked, explaining the association between color and behavioral dominance despite gene flow. We conclude that behavioral dominance asymmetries exist among female color morphs of the fish N. omnicaeruleus, and discuss possible mechanisms that may account for the tight association between color and behavioral dominanc

Integrative Health Care of Dementia in Upper Bavaria – The "Light House" Project IDOB

Das Leuchtturmprojekt Demenz "Integrierte Demenzversorgung in Oberbayern – IDOB" hat zum Ziel, in den Modellregionen München-Ost und Berchtesgadener Land die Versorgung demenzkranker Menschen zu verbessern, mit Hilfe regionaler Versorgungsverbünde, die am individuellen Bedarf Demenzkranker angepasst sind. Demenz-Schweregrad und soziale Situation der teilnehmenden Patienten unterscheiden sich: Patienten in München-Ost sind schwerer erkrankt und leben größtenteils allein; dagegen lebt die Hälfte der Patienten im Berchtesgadener Land im Familienverbund. Die Projekterfahrungen sind in beiden Modellregionen ähnlich: Die Lebensqualität der Patienten hat sich verbessert; während die Versorgung Lücken bei aufsuchender Hilfe und Informations- und Unterstützungsangeboten für Angehörige aufweistThe dementia light house project "integrated care of dementia in Oberbayern – IDOB" aims at improving the care of people with dementia in the German model regions Munich and “Berchtesgadener Land“ by regional care-networks adapted to the individual demand of dementia patients. Severity of dementia and the social situation of participating patients differ: Patients in the city (Munich-East) are more severely demented and are mostly living alone; in contrast half of the patients in the rural “Berchtesgadener Land“ live with their families. Experiences with the project are similar in both model regions: The quality of life of the patients has improved. However, there is lack of health care regarding calling on assistance and information and support for caring family members

Prediction of torsional failure in 22 cadaver femora with and without simulated subtrochanteric metastatic defects: a CT scan-based finite element analysis

BACKGROUND: In metastatic bone disease, prophylactic fixation of impending long bone fracture is preferred over surgical treatment of a manifest fracture. There are no reliable guidelines for prediction of pathological fracture risk, however. We aimed to determine whether finite element (FE) models constructed from quantitative CT scans could be used for predicting pathological fracture load and location in a cadaver model of metastatic bone disease. MATERIAL AND METHODS: Subject-specific FE models were constructed from quantitative CT scans of 11 pairs of human femora. To simulate a metastatic defect, a transcortical hole was made in the subtrochanteric region in one femur of each pair. All femora were experimentally loaded in torsion until fracture. FE simulations of the experimental set-up were performed and torsional stiffness and strain energy density (SED) distribution were determined. RESULTS: In 15 of the 22 cases, locations of maximal SED fitted with the actual fracture locations. The calculated torsional stiffness of the entire femur combined with a criterion based on the local SED distribution in the FE model predicted 82% of the variance of the experimental torsional failure load. INTERPRETATION: In the future, CT scan-based FE analysis may provide a useful tool for identification of impending pathological fractures requiring prophylactic stabilization

A model of cognitive processes and conversational principles in survey interview interaction

In this paper we provide a model of interviewer–respondent interaction in survey interviews. Our model is primarily focused on the occurrence of problems within this interaction that seem likely to affect data quality. Both conversational principles and cognitive processes, especially where they do not match the requirements of the respondent's task, are assumed to affect the course of interactions. The cognitive processes involved in answering a survey question are usually described by means of four steps: interpretation, retrieval, judgement and formatting. Each of these steps may be responsible for different overt problems, such as requests for clarification or inadequate answers. Such problems are likely to affect the course of the interaction through conversational principles which may cause, for example, suggestive behaviour on the part of the interviewer, which may in turn yield new problematic behaviours. However, the respondent may not be the only one who experiences cognitive problems; the interviewer may also have such problems, for example with respect to explaining question meaning to the respondent. Thus the model proposed here, unlike most of the other models which concentrate on the respondent, tries to incorporate cognitive processes and conversational principles with respect to both interviewer and respondent. In particular, the model looks at how cognitive processes and conversational principles affect both the interaction between interview participants and the quality of the eventual answers. Copyright © 2007 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55950/1/1334_ftp.pd

Inulin-grown Faecalibacterium prausnitzii cross-feeds fructose to the human intestinal epithelium

Many chronic diseases are associated with decreased abundance of the gut commensal Faecalibacterium prausnitzii. This strict anaerobe can grow on dietary fibers, e.g., prebiotics, and produce high levels of butyrate, often associated to epithelial metabolism and health. However, little is known about other F. prausnitzii metabolites that may affect the colonic epithelium. Here, we analyzed prebiotic cross-feeding between F. prausnitzii and intestinal epithelial (Caco-2) cells in a “Human-oxygen Bacteria-anaerobic” coculture system. Inulin-grown F. prausnitzii enhanced Caco-2 viability and suppressed inflammation- and oxidative stress-marker expression. Inulin-grown F. prausnitzii produced excess butyrate and fructose, but only fructose efficiently promoted Caco-2 growth. Finally, fecal microbial taxonomy analysis (16S sequencing) from healthy volunteers (n = 255) showed the strongest positive correlation for F. prausnitzii abundance and stool fructose levels. We show that fructose, produced and accumulated in a fiber-rich colonic environment, supports colonic epithelium growth, while butyrate does not