The paradox of magnetobiology: Analysis and prospects for solution

The formulation, content, and corollaries of the so-called kT problem are considered. The problem points to a paradox in the biological effect of weak low-frequency magnetic fields. The conventional formulation of the problem contains implicit assumptions that prove not fully valid according to the results of analysis.     

Clusterings should not be compared by visual inspection: response to Gagné & Proulx

In Heikinheimo et al . ( Journal of Biogeography , 2007, 34 , 1053–1064) we used clustering to analyse European land mammal fauna. Gagné & Proulx criticized our choice of the Euclidean distance measure in the analysis, and advocated the use of the Hellinger distance measure, claiming that this leads to very different clustering results. The criticism fails to take into account the probabilistic nature of the methods used and the fact that in this case the similarity measures correlate strongly. Gagné & Proulx used subjective inspection as the criterion of similarity between clusterings. We show that this is insufficient and misleading. Namely, owing to the local minimum problem, two clustering runs rarely give identical results. In the case of our study, the measured similarity (using the kappa statistic) between the Euclidean- and Hellinger-based clusterings is roughly equal to the similarity between two clusterings that both use the Hellinger distance but different random initialization points.     

微生态调节剂质量标准探讨

微生态调节剂质量标准探讨浙江省药品检验所浙江３１０００４邵惠琴王知坚微生态学是研究生物体与其体内环境的微生态平衡、失调,调整的一门新形成的生命科学分支。我国自８０年代提出来后得到了很快的发展,近年来与之相适应的各种药用微生物制剂也应运而生,且发展迅速...     

Kin Discrimination in Protists: From Many Cells to Single Cells and Backwards

During four decades (1960–1990s), the conceptualization and experimental design of studies in kin recognition relied on work with multicellular eukaryotes, particularly Unikonta (including invertebrates and vertebrates) and some Bikonta (including plants). This pioneering research had an animal behavior approach. During the 2000s, work on taxa‐, clone‐ and kin‐discrimination and recognition in protists produced genetic and molecular evidence that unicellular organisms (e.g. Saccharomyces, Dictyostelium, Polysphondylium, Tetrahymena, Entamoeba and Plasmodium) could distinguish between same (self or clone) and different (diverse clones), as well as among conspecifics of close or distant genetic relatedness. Here, we discuss some of the research on the genetics of kin discrimination/recognition and highlight the scientific progress made by switching emphasis from investigating multicellular to unicellular systems (and backwards). We document how studies with protists are helping us to understand the microscopic, cellular origins and evolution of the mechanisms of kin discrimination/recognition and their significance for the advent of multicellularity. We emphasize that because protists are among the most ancient organisms on Earth, belong to multiple taxonomic groups and occupy all environments, they can be central to reexamining traditional hypotheses in the field of kin recognition, reformulating concepts, and generating new knowledge.     

Bayesian Inference for the Ratio of the Means of Two Normal Populations with Unequal Variances

The problem of making inferences about the ratio of two normal means has been addressed, both from the frequentist and Bayesian perspectives, by several authors. Most of this work is concerned with the homoscedastic case. In contrast, the situation where the variances are not equal has received little attention. Cox (1985) deals, within the frequentist framework, with a model where the variances are related to the means. His results are mainly based on Fieller's theorem whose drawbacks are well known. In this paper we present a Bayesian analysis of this model and discuss some related problems. An agronomical example is used throughout to illustrate the methods.     

Acoustic reflectometry for an in vitro model of a human upper airway using sinusoidal wave packets and the Ware–Aki algorithm

Acoustic reflectometry is often used for estimating the cross-sectional area of a cylindrical cavity when used in combination with an acoustic pulse. The objective of this research is to sweep a spectral bandwidth from 50 Hz to 10 kHz at steps of 50 Hz, with Gaussian sinusoidal wave packets, and to apply the Ware–Aki algorithm. In practice, not only it is difficult to generate a broad spectral bandwidth, but also robust methods are required to compensate for attenuation in the propagating wave and to eliminate a DC offset component generated in its impulse response. This paper looks at using numerical techniques to compute the impulse response and estimate the cross-sectional area as a function of an increment in the frequency response. Preliminary results show that both simulated and reconstructed cross-sectional areas for an in vitro model of a human upper airway may be estimated with an appropriate resolution, suggesting that this method is suitable for such applications.     

When Intuition is Not Enough. Why the Principle of Procreative Beneficence Must Work Much Harder to Justify Its Eugenic Vision

The Principle of Procreative Beneficence (PPB) claims that we have a moral obligation, where choice is possible, to choose to create the best child we can. The existence of this moral obligation has been proposed by John Harris and Julian Savulescu and has proved controversial on many levels, not least that it is eugenics, asking us to produce the best children we can, not for the sake of that child's welfare, but in order to make a better society. These are strong claims that require robust justification that can be open to scrutiny and debate. This article argues that robust justifications are currently lacking in the work of Savulescu and Harris. The justifications provided for their conclusions about this obligation to have the best child possible rely heavily on Derek Parfit's Non‐Identity Problem and the intuitive response this provokes in many of us. Unfortunately Harris and Savulescu do not embrace the entirety of the Non‐Identity Problem and the puzzle that it presents. The Non‐Identity Problem actually provides a refutation of PPB. In order to establish PPB as a credible and defendable principle, Harris and Savulescu need to find what has eluded Parfit and many others: a solution to the Non‐Identity Problem and thus an overturning of the refutation it provides for PPB. While Harris and Savulescu do hint at possible but highly problematic solutions to the Non‐Identity Problem, these are not developed or defended. As a result their controversial is left supported by little more than intuition.     

Global plant-responding mechanisms to salt stress: physiological and molecular levels and implications in biotechnology

The increasing seriousness of salinization aggravates the food, population and environmental issues. Ameliorating the salt-resistance of plants especially the crops is the most effective measure to solve the worldwide problem. The salinity can cause damage to plants mainly from two aspects: hyperosmotic and hyperionic stresses leading to the restrain of growth and photosynthesis. To the adverse effects, the plants derive corresponding strategies including: ion regulation and compartmentalization, biosynthesis of compatible solutes, induction of antioxidant enzymes and plant hormones. With the development of molecular biology, our understanding of the molecular and physiology knowledge is becoming clearness. The complex signal transduction underlying the salt resistance is being illuminated brighter and clearer. The SOS pathway is the central of the cell signaling in salt stress. The accumulation of the compatible solutes and the activation of the antioxidant system are the effective measures for plants to enhance the salt resistance. How to make full use of our understanding to improve the output of crops is a huge challenge for us, yet the application of the genetic engineering makes this possible. In this review, we will discuss the influence of the salt stress and the response of the plants in detail expecting to provide a particular account for the plant resistance in molecular, physiological and transgenic fields.     

生态环境对白芷产量质量的影响

生态环境对白芷产量质量的影响陈兴福,丁德蓉,刘岁荣,卢进,黄文秀（四川省中医药研究院药物种植研究所,南川６４８４０８）ＥｆｆｅｃｔｏｆＥｃｏ－ＥｎｖｉｒｏｎｍｅｎｔｏｎＤａｈｕｒｉａｎＡｎｇｅｌｉｃａＹｉｅｌｄａｎｄＩｔｓＱｕａｌｉｔｙ￥ＣｈｅｎＸｉ...