利用次序统计量估计种群的平均寿命

本文讨论威布尔分布Ｗ（α,λ）中次序统计量的分布;建立了用次序统计量对威布尔分布进行参数估计,进而估计种群平均寿命和方差的方法,该方法可广泛用于可靠性统计产品平均寿命和方差的估计。     

Membrane order perturbation in the presence of antimicrobial peptides by H solid-state NMR spectroscopy

The ²H solid-state NMR spectra of deuterated fatty acyl chains provide direct access to the order of the hydrophobic membrane interior. From the deuterium order parameter profiles of perdeuterated fatty acyl chains the membrane hydrophobic thickness can be calculated. Here we show data obtained from POPC, POPE and mixed POPE/POPG bilayers, representative of bacterial membranes, in the presence of cholesterol or ergosterol and antimicrobial peptaibols. Whereas sterols have a strong ordering effect also on these membranes, the peptides exhibit neutral or disordering effects. By comparing with data from the literature it becomes obvious that cationic amphipathic peptides that probably reside within the interface of phospholipid membranes tend to strongly disorder the packing of the fatty acyl chains, an effect that has been correlated to antimicrobial and DNA transfection activities. In contrast transmembrane sequences or hydrophobic peptides that probably partition deeply into the membrane tend to have only modest disordering activities. The ²H solid-state NMR approach has also been used to monitor the lateral separation of domains rich in anionic phospholipids in the presence of cationic peptides and has thereby provided important insights into their mechanisms of action.     

The structural complexity of DNA templates—Implications on cellular complexity

A previously formulated procedure for the quantitative evaluation of the complexities of molecules and biostructures is applied to assess the complexities of selected genomic DNA sequences. These include: (1) Several E. coli genes, including lacI, as examples of DNA sequences which are nearly as complex as possible (relative complexity=∼1). This is verified by the Lempel-Ziv (LZ) complexity analysis. (2) The telomere of a yeast chromosome, which has a considerable number of regular features that reduce complexity; the telomere shows indeed a lower structural complexity value. (3) A segment of human DNA, gene p53, which has a certain number of regular features such as 29 interspersed alu elements; these features cause a certain reduction in the complexity of the p53 gene, but do not invalidate the (previous) overall conclusion that template complexity is very high. The close to maximal complexity of the transcribed regions of p53 is validated by the LZ compression analysis. The general conclusion is that DNA base sequence composition is the dominant factor determining cellular complexity. The high complexity of DNA arrived at is a direct consequence of the template character of DNA and reflects the role of genomic DNA as a principal regulating element of a cell. It will be a challenge to find systems of lower complexity with the ability to respond to challenges from the environment to the extent that DNA templated systems do. Cellular complexity and template directed activity are thus highly intertwined properties, at the heart of many developmental, behavioral and evolutionary processes.     

Crowds,Affect, and the Mediation of Emergent Collectivities: A Student Strike in Papua New Guinea as an Order-Making Project

ABSTRACT

From the institutional perspective of a university, student strikes mark a time of heightened disorder. In this contribution, I turn this perspective around and analyse a student strike at the University of Goroka in the Papua New Guinea highlands as an order-making project instead. The observed student strike established an alternative regime among students, which was reinforced through a sense of having achieved a superior sophistication of order through the effective, and affective, alignment of minds and bodies into a single entity. Placing the achievement of collective unity in relation to what appears as Melanesian notions of order on one hand, and recent re-evaluations of the psychology of crowds within anthropology and sociology on the other hand, I explore conceptual connections in the work of ‘mediation’ between order making in Melanesia and contemporary (critiques of) affect theory.     

Study of protein dynamics in solution by measurement of 13Cα-13CO NOE and 13CO longitudinal relaxation

Summary ¹³C-¹³CO homonuclear NOE and ¹³CO T₁ relaxation were measured for a 20 kDa protein using tripleresonance pulse sequences. The experiments were sufficiently sensitive to obtain statistically significant differences in relaxation parameters over the molecule. The ¹³C-¹³CO cross-relaxation rate, obtained from these data, is directly proportional to an order parameter describing local motion and it is largely independent of the local correlation time. It is therefore a relatively straightforward observable for the identification of local dynamics.     

Accuracy and selection success in yield trial analyses

Summary Yield trials serve research purposes of estimation and selection. Order statistics are used here to quantify the successes or problems to be expected in selection tasks commonly encountered in breeding and agronomy. Greater accuracy of yield estimates implies greater selection success. A New York soybean yield trial serves as a specific example. The Additive Main effects and Multiplicative Interaction (AMMI) statistical model is used to increase the accuracy of these soybean yield estimates, thereby increasing the probability of successfully selecting, on the basis of the empirical yield data, that genotype which has the maximum true mean. The statistical strategy for increasing accuracy is extremely cost effective relative to the alternative strategy of increasing the number of replications. Better selections increase the speed and effectiveness of breeding programs, and increase the reliability of variety recommendations. Selection tasks are frequently more difficult than may be suspected.This research was supported by the Rhizobotany Project of the USDA-ARS     

Social behavior of early emerging males of a Japanese paper wasp,Polistes chinensis antennalis (Hymenoptera: Vespidae)

Summary Five cases of the early emergence of males in a Japanese paper wasp,Polistes chinensis antennalis, in which male emerged together with the first group of workers, were described. In one case of the five where the queen disappeared before the emergence of male, worker(s) produced female offspring. The frequency of the nests where the early emergence of male was observed was 16.7% (5/30 nests). In two colonies, worker(s) and/or queen chased off males. But in an orphan nest where worker(s) produced female offspring, the dominance order among workers which was similar to that of colony without male was observed. The significance of the early emergence of male in the social evolution of wasps was discussed.