4,074 research outputs found
Forages Improve Livelihoods of Smallholder Farmers with Beef Cattle in South Central Coastal Vietnam
In South Central Coastal Vietnam, on-farm research and farmer experience demonstrated the benefits of growing improved forages as a means of improving the year round quantity and quality of feed available for beef cattle. In Binh Dinh, Phu Yen and Ninh Thuan provinces, five new forage species (Panicum maximum, cv. TD58, Brachiaria hybrid cv. Mulato II, Pennisetum purpureum cv.VA06, Paspalum atratum cv. Terenos and Stylosanthes guianensis cv. CIAT 184) were evaluated for yield and crude protein concentration. There was not a consistent yield difference between locations for the forage grasses, but in Binh Dinh province P. maximum TD58 produced the highest yield. The grasses were comparable in crude protein concentration. Stylo CIAT 184 performed relatively well and had the highest crude protein concentration. All species have potential use, depending on the circumstances and site factors such as fertility, drainage and availability of irrigation. This work was expanded to a total of 45 farmers to gain feedback on farmer experience in growing different forages. The percentage of farmers who “liked” the introduced forages was Mulato II, 92%; TD58, 85%; VA06, 82%; Paspalum, 46%; and Stylo, 36%. By far the most important early socio-economic impact of developing perennial forage plots close to households was an average 50% reduction in the amount of labour and time that farmers spend supplying cut and carry forage to their animals. In addition, the growing of forages can meaningfully reduce the grazing pressure on common grazing lands, thereby lowering the potential for environmental degradation
Assessing the Effect of Piperacillin/Tazobactam on Hematological Parameters in Patients Admitted with Moderate or Severe Foot Infections
Introduction: Piperacillin/tazobactam is a commonly used antibiotic for the empirical treatment of severe diabetic foot infections. One of the most feared complications of this drug is the development of pancytopenia. The aim of this study was to determine whether the use of piperacillin/tazobactam caused any hematological changes in patients admitted with severe diabetes-related foot infections from a specialist multidisciplinary foot clinic. Specifically, looking at whether it caused anemia, leukopenia, neutropenia, or thrombocytopenia. Methods: A 1-year retrospective analysis of patients admitted to a tertiary care center for treatment of diabetes-related foot infection using piperacillin/tazobactam. Hematological indices, urea and electrolytes, and C-reactive protein (CRP) were recorded pretreatment, during treatment, and posttreatment. HbA1c, vitamin B12, folate, thyroid-stimulating hormone, and free thyroxin were also analyzed to exclude any potential confounders as a cause of pancytopenia. Results: A total of 154 patients were admitted between 1 January 2016 and 31 December 2016 who received piperacillin/tazobactam for severe diabetes-related foot infection. On admission, white cell count and CRP were raised and fell significantly within the first 48 h. Other hematological factors did not change. Five patients developed a mild pancytopenia, of which three were unexplained. Conclusion: In this relatively small cohort, pancytopenia did not occur. As such, piperacillin/tazobactam appeared to have a low risk of adverse hematological outcomes and remains the treatment of choice for severe diabetes-related foot infections
Atopic asthmatic immune phenotypes associated with airway microbiota and airway obstruction
© 2017 Turturice et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background: Differences in asthma severity may be related to inflammation in the airways. The lower airway microbiota has been associated with clinical features such as airway obstruction, symptom control, and response to corticosteroids. Objective: To assess the relationship between local airway inflammation, severity of disease, and the lower airway microbiota in atopic asthmatics. Methods: A cohort of young adult, atopic asthmatics with intermittent or mild/moderate persistent symptoms (n = 13) were assessed via bronchoscopy, lavage, and spirometry. These individuals were compared to age matched non-asthmatic controls (n = 6) and to themselves after six weeks of treatment with fluticasone propionate (FP). Inflammation of the airways was assessed via a cytokine and chemokine panel. Lower airway microbiota composition was determined by metagenomic shotgun sequencing. Results: Unsupervised clustering of cytokines and chemokines prior to treatment with FP identified two asthmatic phenotypes (AP), termed AP1 and AP2, with distinct bronchoalveolar lavage inflammatory profiles. AP2 was associated with more obstruction, compared to AP1. After treatment with FP reduced MIP-1β and TNF-α and increased IL-2 was observed. A module of highly correlated cytokines that include MIP-1β and TNF-α was identified that negatively correlated with pulmonary function. Independently, IL-2 was positively correlated with pulmonary function. The airway microbiome composition correlated with asthmatic phenotypes. AP2, prior to FP treatment, was enriched with Streptococcus pneumoniae. Unique associations between IL-2 or the cytokine module and the microbiota composition of the airways were observed in asthmatics subjects prior to treatment but not after or in controls. Conclusion: The underlying inflammation in atopic asthma is related to the composition of microbiota and is associated with severity of airway obstruction. Treatment with inhaled corticosteroids was associated with changes in the airway inflammatory response to microbiota
Models and Heuristics for the Flow-Refuelling Location Problem
Purpose of this paper: Firstly, the paper serves as an overview of the emerging field of flow-refuelling location, which mainly occurs in the context of locating alternative-fuel (hydrogen, electric, liquefied natural gas and hybrid) vehicle refuelling stations. We aim to review and explain models and solution approaches, with a particular focus on mathematical programming formulations. Secondly, we propose a new heuristic for this problem and investigate its performance.
Design/methodology/approach: The subject scope of this paper is the flow-refuelling location model (FRLM). While in most location problems demand arises at customer locations, in so-called flow-capturing models it is associated with journeys (origin-destination pairs). What makes the FRLM even more challenging is that due to the limited driving range of alternative-fuel vehicles, more than one facility may be required to satisfy the demand of a journey. There are currently very few such refuelling stations, but ambitious plans exist for massive development – making this an especially ripe time for researchers to investigate this problem. There already exists a body of work on this problem; however different authors make different model assumptions, making comparison difficult. For example, in some models facilities must lie on the shortest route from origin to destination, while in others detours are allowed. We aim to highlight difference in models in our review. Our proposed methodology is built on the idea of solving the relaxation of the mixed-integer linear programming formulation of the problem, identifying promising variables, fixing their values and solving the resulting (so-called restricted) problems optimally. It is somewhat similar to Kernel Search which has recently gained popularity. We also use a parallel computing strategy to simultaneously solve a number of restricted problems with less computation effort for large-sized instances.
Findings: Our experimental results show that the proposed heuristic can find optimal solutions in a reasonable amount of time, outperforming other heuristics from the literature.
Value: We believe the paper is of value to both academics and practitioners. The review should help researchers new to this field to orient themselves in the maze of different problem versions, while helping practitioners identify models and approaches applicable to their particular problem. The heuristic proposed can be directly used by practitioners; we hope it will spark further works on this area of logistics but also on other optimisation problems where Kernel Search type methods can be applied.
Research limitations: This being the first paper applying a restricted-subproblem approach to this problem it is necessarily limited in scope. Applying a traditional Kernel Search method would be an interesting next step. The proposed heuristic should also be extended to cover for more than just one FRLM model: certainly the capacitated FRLM, the FRLM with deviation, the fixed-charge FRLM and the multi-period FRLM should be investigated.
Practical implications: Our work adds to a body of research that can inform decisionmakers
at governmental or international level on strategic decisions relating to the establishment or development of alternative-fuel refuelling station networks
Sublinear time algorithms for earth mover's distance
We study the problem of estimating the Earth Mover’s Distance (EMD) between probability distributions
when given access only to samples of the distributions. We give closeness testers and additive-error
estimators over domains in [0, 1][superscript d], with sample complexities independent of domain size – permitting
the testability even of continuous distributions over infinite domains. Instead, our algorithms depend on
other parameters, such as the diameter of the domain space, which may be significantly smaller. We also
prove lower bounds showing the dependencies on these parameters to be essentially optimal. Additionally,
we consider whether natural classes of distributions exist for which there are algorithms with better
dependence on the dimension, and show that for highly clusterable data, this is indeed the case. Lastly,
we consider a variant of the EMD, defined over tree metrics instead of the usual l 1 metric, and give tight
upper and lower bounds
An efficient heuristic algorithm for the alternative-fuel station location problem
We have developed an efficient heuristic algorithm for location of alternative-fuel stations. The algorithm is constructed based on solving the sequence of subproblems restricted on a set of promising station candidates, and fixing a number of the best promising station locations. The set of candidates is initially determined by solving a relaxation model, and then modified by exchanging some stations between the promising candidate set and the remaining station set. A number of the best station candidates in the promising candidate set can be fixed to improve computation time. In addition, a parallel computing strategy is integrated into solving simultaneously the set of subproblems to speed up computation time. Experimental results carried out on the benchmark instances show that our algorithm outperforms genetic algorithm and greedy algorithm. As compared with CPLEX solver, our algorithm can obtain all the optimal solutions on the tested instances with less computation time
Design of Experiments for Screening
The aim of this paper is to review methods of designing screening
experiments, ranging from designs originally developed for physical experiments
to those especially tailored to experiments on numerical models. The strengths
and weaknesses of the various designs for screening variables in numerical
models are discussed. First, classes of factorial designs for experiments to
estimate main effects and interactions through a linear statistical model are
described, specifically regular and nonregular fractional factorial designs,
supersaturated designs and systematic fractional replicate designs. Generic
issues of aliasing, bias and cancellation of factorial effects are discussed.
Second, group screening experiments are considered including factorial group
screening and sequential bifurcation. Third, random sampling plans are
discussed including Latin hypercube sampling and sampling plans to estimate
elementary effects. Fourth, a variety of modelling methods commonly employed
with screening designs are briefly described. Finally, a novel study
demonstrates six screening methods on two frequently-used exemplars, and their
performances are compared
- …