A Multistage Stochastic Programming Approach to the Dynamic and Stochastic VRPTW - Extended version

We consider a dynamic vehicle routing problem with time windows and stochastic customers (DS-VRPTW), such that customers may request for services as vehicles have already started their tours. To solve this problem, the goal is to provide a decision rule for choosing, at each time step, the next action to perform in light of known requests and probabilistic knowledge on requests likelihood. We introduce a new decision rule, called Global Stochastic Assessment (GSA) rule for the DS-VRPTW, and we compare it with existing decision rules, such as MSA. In particular, we show that GSA fully integrates nonanticipativity constraints so that it leads to better decisions in our stochastic context. We describe a new heuristic approach for efficiently approximating our GSA rule. We introduce a new waiting strategy. Experiments on dynamic and stochastic benchmarks, which include instances of different degrees of dynamism, show that not only our approach is competitive with state-of-the-art methods, but also enables to compute meaningful offline solutions to fully dynamic problems where absolutely no a priori customer request is provided.Comment: Extended version of the same-name study submitted for publication in conference CPAIOR201

The promotion of local wellbeing: A primer for policymakers

There is growing interest among policymakers in the promotion of wellbeing as an objective of public policy. In particular, local authorities have been given powers to undertake action to promote wellbeing in their area. Recent advances in the academic literature on wellbeing are giving rise to an increasingly detailed picture of the factors that determine people’s subjective wellbeing (how they think and feel about their lives). However, the concept of subjective wellbeing is poorly understood within local government and much of the evidence base is extremely recent. I therefore review the literature on the definition, measurement, and determinants of wellbeing, and discuss some of its implications for local public policy

CHY representations for gauge theory and gravity amplitudes with up to three massive particles

We show that a wide class of tree-level scattering amplitudes involving scalars, gauge bosons, and gravitons, up to three of which may be massive, can be expressed in terms of a Cachazo-He-Yuan representation as a sum over solutions of the scattering equations. These amplitudes, when expressed in terms of the appropriate kinematic invariants, are independent of the masses and therefore identical to the corresponding massless amplitudes.Comment: 20 pages, 1 figure; v2: minor typos corrected, published versio

Síndrome de Stevens-Johnson. Apresentação de Caso Clínico

Introdução: A Síndrome de Stevens-Johnson (SSJ) é uma doença mucocutânea rara e potencialmente fatal, mais frequente no sexo masculino, cuja incidência aumenta com a idade e em determinados grupos de risco. A SSJ e a Necrólise Tóxica Epidérmica (NET) são duas entidades da mesma doença, com severidade diferente. A etiologia não é clara, mas pensa-se que se deva maioritariamente a reacções adversas a fármacos. Caso clínico: Um jovem de 17 anos de idade, sem antecedentes pessoais relevantes, foi observado no Serviço de Urgência por surgimento de lesões maculopapulares, com 3 dias de evolução, dispersas pela face, cavidade oral, tronco e extremidades, com prostração e taquicardia. Foi internado com o diagnóstico de SSJ. Discussão e Conclusões: O SSJ e a NET têm grande morbilidade e considerável mortalidade. O rápido reconhecimento desta identidade, com a remoção do fármaco desencadeador é essencial. A perda da função de barreira da pele, com a consequente alteração da homeostasia, implica muitas vezes a manutenção da terapêutica de suporte em Unidades de Cuidados Intensivos ou de Queimados.info:eu-repo/semantics/publishedVersio

Chronic non-specific low back pain - sub-groups or a single mechanism?

Copyright 2008 Wand and O'Connell; 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 cited.Background: Low back pain is a substantial health problem and has subsequently attracted a considerable amount of research. Clinical trials evaluating the efficacy of a variety of interventions for chronic non-specific low back pain indicate limited effectiveness for most commonly applied interventions and approaches. Discussion: Many clinicians challenge the results of clinical trials as they feel that this lack of effectiveness is at odds with their clinical experience of managing patients with back pain. A common explanation for this discrepancy is the perceived heterogeneity of patients with chronic non-specific low back pain. It is felt that the effects of treatment may be diluted by the application of a single intervention to a complex, heterogeneous group with diverse treatment needs. This argument presupposes that current treatment is effective when applied to the correct patient. An alternative perspective is that the clinical trials are correct and current treatments have limited efficacy. Preoccupation with sub-grouping may stifle engagement with this view and it is important that the sub-grouping paradigm is closely examined. This paper argues that there are numerous problems with the sub-grouping approach and that it may not be an important reason for the disappointing results of clinical trials. We propose instead that current treatment may be ineffective because it has been misdirected. Recent evidence that demonstrates changes within the brain in chronic low back pain sufferers raises the possibility that persistent back pain may be a problem of cortical reorganisation and degeneration. This perspective offers interesting insights into the chronic low back pain experience and suggests alternative models of intervention. Summary: The disappointing results of clinical research are commonly explained by the failure of researchers to adequately attend to sub-grouping of the chronic non-specific low back pain population. Alternatively, current approaches may be ineffective and clinicians and researchers may need to radically rethink the nature of the problem and how it should best be managed

The cost of uncomplicated childhood fevers to Kenyan households: implications for reaching international access targets

Abstract Background Fever is the clinical hallmark of malaria disease. The Roll Back Malaria (RBM) movement promotes prompt, effective treatment of childhood fevers as a key component to achieving its optimistic mortality reduction goals by 2010. A neglected concern is how communities will access these new medicines promptly and the costs to poor households when they are located in rural areas distant to health services. Methods We assemble data developed between 2001 and 2002 in Kenya to describe treatment choices made by rural households to treat a child's fever and the related costs to households. Using a cost-of-illness approach, we estimate the expected cost of a childhood fever to Kenyan households in 2002. We develop two scenarios to explore how expected costs to households would change if more children were treated at a health care facility with an effective antimalarial within 48 hours of fever onset. Results 30% of uncomplicated fevers were managed at home with modern medicines, 38% were taken to a health care facility (HCF), and 32% were managed at home without the use of modern medicines. Direct household cash expenditures were estimated at $0.44 per fever, while the total expected cost to households (cash and time) of an uncomplicated childhood fever is estimated to be$1.91. An estimated mean of 1.42 days of caretaker time devoted to each fever accounts for the majority of household costs of managing fevers. The aggregate cost to Kenyan households of managing uncomplicated childhood fevers was at least $96 million in 2002, equivalent to 1.00$1.86 because caretakers also save time with prompt treatment if the child has malaria. Conclusion The management of uncomplicated childhood fevers imposes substantial costs on Kenyan households. Achieving substantial improvements in the numbers of fevers treated within 48 hours at a HCF with an effective antimalarial drug (Scenario 1) will not impose additional costs on households. Achieving additional improvements in fevers treated promptly at a HCF (Scenario 2) will impose additional costs on some households roughly equal to average cash expenses for transportation to a HCF. Additional financing mechanisms that further reduce the costs of accessing care at a HCF and/or that make artemisinin-based combination therapies (ACTs) accessible for home management need to be developed and evaluated as a top priority.</p

Developments in the Ni–Nb–Zr amorphous alloy membranes

Most of the global H2 production is derived from hydrocarbon-based fuels, and efficient H2/CO2 separation is necessary to deliver a high-purity H2 product. Hydrogen-selective alloy membranes are emerging as a viable alternative to traditional pressure swing adsorption processes as a means for H2/CO2 separation. These membranes can be formed from a wide range of alloys, and those based on Pd are the closest to commercial deployment. The high cost of Pd (USD *31,000 kg-1) is driving the development of less-expensive alternatives, including inexpensive amorphous (Ni60Nb40)100-xZrx alloys. Amorphous alloy membranes can be fabricated directly from the molten state into continuous ribbons via melt spinning and depending on the composition can exhibit relatively high hydrogen permeability between 473 and 673 K. Here we review recent developments in these low-cost membrane materials, especially with respect to permeation behavior, electrical transport properties, and understanding of local atomic order. To further understand the nature of these solids, atom probe tomography has been performed, revealing amorphous Nb-rich and Zr-rich clusters embedded in majority Ni matrix whose compositions deviated from the nominal overall composition of the membrane

As Far as the Eye Can See: Relationship between Psychopathic Traits and Pupil Response to Affective Stimuli

Psychopathic individuals show a range of affective processing deficits, typically associated with the interpersonal/affective component of psychopathy. However, previous research has been inconsistent as to whether psychopathy, within both offender and community populations, is associated with deficient autonomic responses to the simple presentation of affective stimuli. Changes in pupil diameter occur in response to emotionally arousing stimuli and can be used as an objective indicator of physiological reactivity to emotion. This study used pupillometry to explore whether psychopathic traits within a community sample were associated with hypo-responsivity to the affective content of stimuli. Pupil activity was recorded for 102 adult (52 female) community participants in response to affective (both negative and positive affect) and affectively neutral stimuli, that included images of scenes, static facial expressions, dynamic facial expressions and sound-clips. Psychopathic traits were measured using the Triarchic Psychopathy Measure. Pupil diameter was larger in response to negative stimuli, but comparable pupil size was demonstrated across pleasant and neutral stimuli. A linear relationship between subjective arousal and pupil diameter was found in response to sound-clips, but was not evident in response to scenes. Contrary to predictions, psychopathy was unrelated to emotional modulation of pupil diameter across all stimuli. The findings were the same when participant gender was considered. This suggests that psychopathy within a community sample is not associated with autonomic hypo-responsivity to affective stimuli, and this effect is discussed in relation to later defensive/appetitive mobilisation deficits

Global nuts and local mangoes: a critical reading of the UNDP Growing Sustainable Business Initiative in Kenya

This article provides a conceptual and empirical assessment of UN brokered partnerships that seek to deepen or create inclusive and sustainable agricultural supply chains in sub-Saharan Africa. More specifically it appraises the decision-making mechanisms, processes of partnership brokerage and project implementation within the UNDP Growing Sustainable Business Initiative (GSB) in Kenya. The paper argues that the lack of bottom-up participation in decision-making mechanisms and the predominantly economic imperatives driving the GSB partnership projects have failed to reach out to the partnerships’ intended beneficiaries—Kenyan small producers of nuts and mangoes. In conclusion it is suggested that opening up the GSB platform might hold the promise of reconciling sustainable business models with (some) poverty reduction