On the WILCOXON-MANN-WHITNEY-Test as Nonparametric Analogue and Extension of t-Test

In the present paper some basic aspects of the WILCOXON -MANN -WHITNEY -test under various assumptions concerning the underlying distributions are studied. Starting with a formal analogy to Student's t-test its specific sensibility is worked out and the connexion to the problem of testing differences in location is discussed in detail as well as to the model with ordered alternatives. Further a counter example is given showing that the common verbal formulation the WILCOXON -MANN -WHITNEY -test being a test on ‘differences in distribution’ in general is misleading. As an example of an extended application of the WILCOXON -MANN -WHITNEY -statistic the test of POTT-HOFF (1963) on differences in medians of symmetric distributions is treated together with a discussion on suitable variance estimators to guarantee appropriate asymptotic distribution.     

School start time influences melatonin and cortisol levels in children and adolescents – a community-based study

School start time influences sleep parameters. Differences between circadian sleep parameters on weekends and weekdays have been associated with obesity, sleep, and psychiatric disorders. Moreover, circadian rhythm dysregulation affects the secretion of some hormones, such as melatonin and cortisol. In the current study, we investigate the effect of school start time on cortisol and melatonin levels in a community sample of Brazilian children and adolescents. This was a cross-sectional study of 454 students (mean age, 12.81 ± 2.56 years; 58.6% female). From this sample, 80 participants were randomly selected for saliva collection to measure melatonin and cortisol levels. Circadian sleep parameters were assessed by self-reported sleep and wake up schedules and the Morningness–Eveningness Questionnaire. The outcomes, salivary melatonin and cortisol levels, were measured in morning, afternoon and night saliva samples, and behavior problems were assessed using the Child Behavior Checklist (CBCL). The main results revealed that morning school start time decreased the secretion of melatonin. Morning melatonin levels were significantly positively correlated with the sleep midpoint on weekdays and on weekends. Afternoon melatonin levels were positively correlated with the sleep midpoint on weekends in the morning school students. Conversely, in the afternoon school students, night melatonin levels were negatively correlated with the sleep midpoint on weekdays. Cortisol secretion did not correlate with circadian sleep parameters in any of the school time groups. In conclusion, school start time influences melatonin secretion, which correlated with circadian sleep parameters. This correlation depends on the presence of psychiatric symptoms. Our findings emphasize the importance of drawing attention to the influence of school start time on the circadian rhythm of children and adolescents.     

A survey of unresolved problems in life cycle assessment

Background, aims, and scope  Life cycle assessment (LCA) stands as the pre-eminent tool for estimating environmental effects caused by products and processes from ‘cradle to grave’ or ‘cradle to cradle.’ It exists in multiple forms, claims a growing list of practitioners, and remains a focus of continuing research. Despite its popularity and codification by organizations such as the International Organization for Standards and the Society of Environmental Toxicology and Chemistry, life cycle assessment is a tool in need of improvement. Multiple authors have written about its individual problems, but a unified treatment of the subject is lacking. The following literature survey gathers and explains issues, problems and problematic decisions currently limiting LCA’s goal and scope definition and life cycle inventory phases. Main features  The review identifies 15 major problem areas and organizes them by the LCA phases in which each appears. This part of the review focuses on the first 7 of these problems occurring during the goal and scope definition and life cycle inventory phases. It is meant as a concise summary for practitioners interested in methodological limitations which might degrade the accuracy of their assessments. For new researchers, it provides an overview of pertinent problem areas toward which they might wish to direct their research efforts. Results and discussion  Multiple problems occur in each of LCA’s four phases and reduce the accuracy of this tool. Considering problem severity and the adequacy of current solutions, six of the 15 discussed problems are of paramount importance. In LCA’s first two phases, functional unit definition, boundary selection, and allocation are critical problems requiring particular attention. Conclusions and recommendations  Problems encountered during goal and scope definition arise from decisions about inclusion and exclusion while those in inventory analysis involve flows and transformations. Foundational decisions about the basis of comparison (functional unit), bounds of the study, and physical relationships between included processes largely dictate the representativeness and, therefore, the value of an LCA. It is for this reason that problems in functional unit definition, boundary selection, and allocation are the most critical examined in the first part of this review.

Modelling HIV immune response and validation with clinical data

A system of ordinary differential equations is formulated to describe the pathogenesis of HIV infection, wherein certain features that have been shown to be important by recent experimental research are incorporated in the model. These include the role of CD4+memory cells that serve as a major reservoir of latently infected cells, a critical role for T-helper cells in the generation of CD8 memory cells capable of efficient recall response, and stimulation by antigens other than HIV. A stability analysis illustrates the capability of this model in admitting multiple locally asymptotically stable (locally a.s.) off-treatment equilibria. We show that this more biologically detailed model can exhibit the phenomenon of transient viremia experienced by some patients on therapy with viral load levels suppressed below the detection limit. We also show that the loss of CD4+T-cell help in the generation of CD8+memory cells leads to larger peak values for the viral load during transient viremia. Censored clinical data is used to obtain parameter estimates. We demonstrate that using a reduced set of 16 free parameters, obtained by fixing some parameters at their population averages, the model provides reasonable fits to the patient data and, moreover, that it exhibits good predictive capability. We further show that parameter values obtained for most clinical patients do not admit multiple locally a.s off-treatment equilibria. This suggests that treatment to move from a high viral load equilibrium state to an equilibrium state with a lower (or zero) viral load is not possible for these patients.     

铁线莲属研究随记(Ⅱ)

(1)对铁线链属以下诸种Clematis potaninii Maxim., C．heynei Rau,C．trichotoma Nakai,C．apiculata Hook．f.&; Thoms., C．theobromina Dunn,C．hedysarifolia DC．和C．dissecta Baker的系统位置进行了讨论,提出了新见解;(2)过去一些作者或不承认C．trifida Hook．,C．pimpinellifolia Hook.,C．oligophylla Hook．,和Clematopsis lineariloba Hutch诸种,或进行降级,作为种下分类群处理。本文作者在研究了有关标本之后认为上述4种有明显区别特征,均应成立;(3)对裂叶铁线莲Clematis parviloba Gardn．&; Champ．的5个变种,短毛铁线莲C．puberula Hook．f.&; Thoms．的4个变种和丝铁线莲组sect．Naraveliopsis Hand.-Mazz．的20个种做出新的分类安排;(4)归并了subsect．Potanimianae W．T．Wang,C．heynei M．Johnson,C．petelotii Gagnep．以及其他几个学名;(5)描述了2新亚组,4新系,3新种和3新变种;(6)做出了3个新等级,4个新组合。     

APFA:Ameliorated Pathfinder Algorithm for Engineering Applications

Pathfinder algorithm(PFA)is a swarm intelligent optimization algorithm inspired by the collective activity behavior of swarm animals,imitating the leader in the population to guide followers in finding the best food source.This algorithm has the characteristics of a simple structure and high performance.However,PFA faces challenges such as insufficient popula-tion diversity and susceptibility to local optima due to its inability to effectively balance the exploration and exploitation capabilities.This paper proposes an Ameliorated Pathfinder Algorithm called APFA to solve complex engineering optimiza-tion problems.Firstly,a guidance mechanism based on multiple elite individuals is presented to enhance the global search capability of the algorithm.Secondly,to improve the exploration efficiency of the algorithm,the Logistic chaos mapping is introduced to help the algorithm find more high-quality potential solutions while avoiding the worst solutions.Thirdly,a comprehensive following strategy is designed to avoid the algorithm falling into local optima and further improve the convergence speed.These three strategies achieve an effective balance between exploration and exploitation overall,thus improving the optimization performance of the algorithm.In performance evaluation,APFA is validated by the CEC2022 benchmark test set and five engineering optimization problems,and compared with the state-of-the-art metaheuristic algo-rithms.The numerical experimental results demonstrated the superiority of APFA.     

Die Haltung von Bartvögeln (Capitonidae,Piciformes) in deutschen Zoos und in Privathand – ein unbewältigtes Problem

No less than 52 species of barbets have been imported and kept in German zoos during the period between 1960 and 2000. In the first years some (world) first breeding records came from several zoos, Frankfurt with six world first records as the most successful one. Today only two species, the Bearded Barbet (Lybius dubius) and the Red-and-yellow Barbet (Trachyphonus erythrocephalus), breed regularly in ten respectively 14 German zoos and bird parks. The majority of the other species have been lost since, e.g. for future breeding projects. There are also some records of successful broods of barbets in private facilities, but the two species mentioned above are also on top of the list of the breeding records. The problems of keeping and breeding barbets in captivity, their life span, diseases and adequate housing conditions are compiled from data of the literature.