Maximin and maximal solutions for linear programming problems with possibilistic uncertainty

We consider linear programming problems with uncertain constraint coefficients described by intervals or, more generally, possi-bility distributions. The uncertainty is given a behavioral interpretation using coherent lower previsions from the theory of imprecise probabilities. We give a meaning to the linear programming problems by reformulating them as decision problems under such imprecise-probabilistic uncer-tainty. We provide expressions for and illustrations of the maximin and maximal solutions of these decision problems and present computational approaches for dealing with them

Bioelectrochemical Systems for the Treatment of Wastewater and Methane Production

Long-term spaceflight will require technology that is self-sustaining, while minimizing volume and mass. Bioelectrochemical systems (BES) have the ability to recover valuable resources, process waste, and generate a small amount of electrical current, via microorganisms, while satisfying the above criteria. We are currently working on small scale BES reactors that will generate electricity from the breakdown of urine and utilize the electrical current to catalyze synthesis of products including water and methane

Variable neighbourhood decomposition search for 0-1 mixed integer programs

In this paper we propose a new hybrid heuristic for solving 0-1 mixed integer programs based on the principle of variable neighbourhood decomposition search. It combines variable neighbourhood search with a general-purpose CPLEX MIP solver. We perform systematic hard variable fixing (or diving) following the variable neighbourhood search rules. The variables to be fixed are chosen according to their distance from the corresponding linear relaxation solution values. If there is an improvement, variable neighbourhood descent branching is performed as the local search in the whole solution space. Numerical experiments have proven that exploiting boundary effects in this way considerably improves solution quality. With our approach, we have managed to improve the best known published results for 8 out of 29 instances from a well-known class of very di±cult MIP problems. Moreover, computational results show that our method outperforms the CPLEX MIP solver, as well as three other recent most successful MIP solution methods

The Utilization of Urine Processing for the Advancement of Life Support Technologies

The success of long-duration missions will depend on resource recovery and the self-sustainability of life support technologies. Current technologies used on the International Space Station (ISS) utilize chemical and mechanical processes, such as filtration, to recover potable water from urine produced by crewmembers. Such technologies have significantly reduced the need for water resupply through closed-loop resource recovery and recycling. Harvesting the important components of urine requires selectivity, whether through the use of membranes or other physical barriers, or by chemical or biological processes. Given the chemical composition of urine, the downstream benefits of urine processing for resource recovery will be critical for many aspects of life support, such as food production and the synthesis of biofuels. This paper discusses the beneficial components of urine and their potential applications, and the challenges associated with using urine for nutrient recycling for space application

Detection of Dengue Virus in Acutely Febrile Children in Kenya

The burden of dengue virus in Kenya is unknown, and is likely grossly underestimated due to febrile illnesses,often being presumptively treated as malaria , which is endemic. Additionally, Dengue fever can be fatal if left improperly treated especially in children who have lesser-developed immune systems. The objective of this ongoing study is to determine the incidence of dengue fever as the etiology of fever in febrile children in Western Kenya. In this ongoing study, children ages ≤17 presenting with febrile illness to our recruitment sites, had serum samples drawn for testing. For the purposes of the current study, RNA extracted from a subset of these samples (n=19) was reverse transcribed into cDNA and then tested for the presence of dengue virus by PCR followed by agarose gel electrophoresis. For positive samples, use of a sequential PCR reaction with dengue serotype-specific primer sets then enabled determination of the viral serotypes circulating in this population. Our preliminary data confirms the presence of dengue virus as a possible etiology of fever in children in Kenya with 2 out of the original 19 patient samples testing positive for DENV. Therefore, the data from the samples reports a Dengue infection rate of 10.5%. This preliminary data from our ongoing study at this time is too small to accurately determine the incidence of acute DENV infections in children with fever in Kenya; however, identification of DENV in the serum of acutely febrile children suggests that DENV is likely an important cause of fevers in Kenyan children

The Hierarchical Taxonomy of Psychopathology (HiTOP) Is Not an Improvement Over the DSM

DeYoung and colleagues did not sufficiently address three fundamental flaws with HiTOP. First, HiTOP was created using a simple structure factor analytic approach, which does not adequately represent the dimensional space of the symptoms of psychopathology. Consequently, HiTOP is not the empirical structure of psychopathology. Second, factor analysis and dimensional ratings do not fix the problems inherent to descriptive (folk) classification; self-reported symptoms are still the basis upon which clinical judgments about people are made. Finally, HiTOP is not ready to use in real-world clinical settings. There is currently no empirical evidence demonstrating that clinicians who use HiTOP have better clinical outcomes than those who use the DSM. In sum, HiTOP is a factor analytic variation of the DSM that does not get us closer to a more valid and useful taxonomy

Folk Classification and Factor Rotations:Whales, Sharks, and the Problems With the Hierarchical Taxonomy of Psychopathology (HiTOP)

The Hierarchical Taxonomy of Psychopathology (HiTOP) uses factor analysis to group self-reported symptoms of mental illness (i.e., like goes with like). It is hailed as a significant improvement over other diagnostic taxonomies. However, the purported advantages and fundamental assumptions of HiTOP have received little, if any, scientific scrutiny. We critically evaluated five fundamental claims about HiTOP. We conclude that HiTOP does not demonstrate a high degree of verisimilitude and has the potential to hinder progress on understanding the etiology of psychopathology. It does not lend itself to theory building or taxonomic evolution, and it cannot account for multifinality, equifinality, or developmental and etiological processes. In its current form, HiTOP is not ready to use in clinical settings and may result in algorithmic bias against underrepresented groups. We recommend a bifurcation strategy moving forward in which the Diagnostic and Statistical Manual of Mental Disorders is used in clinical settings while researchers focus on developing a falsifiable theory-based classification system

Neurodegenerative Disease Caregivers' 5-HTTLPR Genotype Moderates the Effect of Patients' Empathic Accuracy Deficits on Caregivers' Well-Being.

ObjectiveTo test the hypothesis that a functional polymorphism of the serotonin transporter gene (serotonin-transporter-linked polymorphic region [5-HTTLPR]), which is thought to be associated with differential environmental sensitivity, moderates the association between low levels of empathic accuracy (i.e., ability to recognize emotions in others) in patients with neurodegenerative disease and caregivers' well-being.MethodsParticipants were 54 patients with neurodegenerative disease and their caregivers. Patients' empathic accuracy was measured using a dynamic tracking task in which they continuously rated the emotions of a character in a film; accuracy was determined by comparing patient ratings with those made by an expert panel. Caregivers provided a saliva sample for genotyping. Caregivers' well-being was measured as a latent construct indicated by validated measures of depression, anxiety, and negative affect.ResultsLower levels of patients' empathic accuracy were associated with lower levels of caregivers' well-being. Importantly, caregivers' 5-HTTLPR genotype moderated this association such that lower empathic accuracy in patients predicted lower well-being for caregivers with the short/short genotype (standardized β = 0.66), but not for caregivers with the short/long (standardized β = 0.05) or long/long genotypes (standardized β = -0.21).ConclusionConsistent with previous findings that the short/short variant of 5-HTTLPR is associated with greater sensitivity to environmental influences, caregivers with the short/short variant manifest lower well-being when caring for a patient with low levels of empathic accuracy than caregivers with the other variants. This finding contributes to the authors' understanding of biological factors associated with individual differences in caregiver vulnerability and resilience