Social encounter networks: characterizing Great Britain

A major goal of infectious disease epidemiology is to understand and predict the spread of infections within human populations, with the intention of better informing decisions regarding control and intervention. However, the development of fully mechanistic models of transmission requires a quantitative understanding of social interactions and collective properties of social networks. We performed a cross-sectional study of the social contacts on given days for more than 5000 respondents in England, Scotland and Wales, through postal and online survey methods. The survey was designed to elicit detailed and previously unreported measures of the immediate social network of participants relevant to infection spread. Here, we describe individual-level contact patterns, focusing on the range of heterogeneity observed and discuss the correlations between contact patterns and other socio-demographic factors. We find that the distribution of the number of contacts approximates a power-law distribution, but postulate that total contact time (which has a shorter-tailed distribution) is more epidemiologically relevant. We observe that children, public-sector and healthcare workers have the highest number of total contact hours and are therefore most likely to catch and transmit infectious disease. Our study also quantifies the transitive connections made between an individual''s contacts (or clustering); this is a key structural characteristic of social networks with important implications for disease transmission and control efficacy. Respondents'' networks exhibit high levels of clustering, which varies across social settings and increases with duration, frequency of contact and distance from home. Finally, we discuss the implications of these findings for the transmission and control of pathogens spread through close contact.     

Synthesis of Southern (C1'-C11') and Eastern (C8-C18) Fragments of Pamamycin-607, an Aerial Mycelium-inducing Substance of Streptomyces alboniger

Synthesis of the southern C1'-C11' and eastern C8-C18 fragments of pamamycin-607, an aerial mycelium-inducing substance of Streptomyces alboniger, was achieved. The southern fragment was synthesized by using the Evans aldol reaction and cis-selective iodoetherification as the key steps in a 9.6% overall yield (7 steps). The eastern fragment was constructed via the Julia coupling reaction and cis-selective iodoetherification in a 3.0% overall yield (8 steps from the known epoxide).     

Metabolism of Isoxathion,O, O-Diethyl O-(5-Phenyl-3-isoxazolyl) phosphorothioate in the Rats

Excretion, distribution and metabolism of the insecticide, Isoxathion, administered orally in male Wistar-strain rats, were investigated with a carbon-14 labeled chemical. During 96 hr, approximately 85% and 14% of the total radioactivity were excreted in the urine and feces. Distribution of isoxathion after oral administration in the rats was investigated by means of whole-body autoradiographic technique and measurement of radioactivity in the tissues. At least eleven radioactive metabolites were detected, four of which were structurally determined. They were 3-hydroxy-5-phenylisoxazole, 3-(β-d-glucopyranuronosyloxy)-5-phenylisoxazole, 5-phenyl-3-isoxazolyl sulfate and hippuric acid.     

RNA approaches the B‐form in stacked single strand dinucleotide contexts

Duplex RNA adopts an A‐form structure, while duplex DNA interconverts between the A‐ and B‐forms depending on the environment. The C2′‐endo sugar pucker seen in B‐form DNA can occur infrequently in ribose sugars as well, but RNA is not understood to assume B‐form conformations. Through analysis of over 45,000 stacked single strand dinucleotide (SSD) crystal structure conformations, this study demonstrates that RNA is capable of adopting a wide conformational range between the canonical A‐ and B‐forms at the localized SSD level, including many B‐form‐like conformations. It does so through C2′‐endo ribose conformations in one or both nucleotides, and B‐form‐like neighboring base stacking patterns. As chemical reactions on nucleic acids involve localized changes in chemical bonds, the understanding of how enzymes distinguish between DNA and RNA nucleotides is altered by the energetic accessibility of these rare B‐form‐like RNA SSD conformations. The existence of these conformations also has direct implications in parametrization of molecular mechanics energy functions used extensively to model nucleic acid behavior., 2016. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 65–82, 2016     

河北张家口康巴诺尔湖国家湿地公园遗鸥繁殖群新发现

2014年4月14日在张家口市康保县康巴诺尔湖国家湿地公园(东经114°35′06″~114°36′32″,北纬41°49′05″~41°50′33″)发现遗鸥(Larus relictus)3 000余只。同年7月在湖边发现新繁殖的遗鸥幼鸟觅食。2015年4月底发现遗鸥在湖心岛筑巢产卵,同年6月采用国产大疆精灵3四轴航拍飞行器航拍法及样方法统计湖心岛遗鸥种群数量,共记录遗鸥成鸟2 100余只,806巢,出壳雏鸟2 080只。此次发现属于我国遗鸥繁殖地的新发现。     

Multidimensional biases,gaps and uncertainties in global plant occurrence information

Plants are a hyperdiverse clade that plays a key role in maintaining ecological and evolutionary processes as well as human livelihoods. Biases, gaps and uncertainties in plant occurrence information remain a central problem in ecology and conservation, but these limitations remain largely unassessed globally. In this synthesis, we propose a conceptual framework for analysing gaps in information coverage, information uncertainties and biases in these metrics along taxonomic, geographical and temporal dimensions, and apply it to all c. 370 000 species of land plants. To this end, we integrated 120 million point‐occurrence records with independent databases on plant taxonomy, distributions and conservation status. We find that different data limitations are prevalent in each dimension. Different metrics of information coverage and uncertainty are largely uncorrelated, and reducing taxonomic, spatial or temporal uncertainty by filtering out records would usually come at great costs to coverage. In light of these multidimensional data limitations, we discuss prospects for global plant ecological and biogeographical research, monitoring and conservation and outline critical next steps towards more effective information usage and mobilisation. Our study provides an empirical baseline for evaluating and improving global floristic knowledge, along with a conceptual framework that can be applied to study other hyperdiverse clades.     

Effective aerial monitoring of cyanobacterial harmful algal blooms is dependent on understanding cellular migration

Cyanobacterial harmful algal blooms (CHABs) degrade water quality and may produce toxins. The distribution of CHABs can change rapidly due to variations in population dynamics and environmental conditions. Biological and ecological aspects of CHABs were studied in order to better understand CHABs dynamics. Field experiments were conducted near Hartington, Ontario, Canada in ponds dominated by Microcystis aeruginosa and CHABs floating experiments were conducted at Lake Taihu during the summers of 2015 and 2016. Single colonies composed of hundreds to thousands of cells with an average median of 0.2–0.5 mm in diameter were the basic form assumed by the Microcystis, and this remained the same throughout the growing season. Thorough mixing of the water column followed by calm conditions resulted in over 90% of the cyanobacteria floating after 1 h. Multiple colonies floated on the water surface in four types of assemblages: aggregates, ribbons, patches, and mats. It is the mats that are conventionally considered the blooming stage of cyanobacteria.Presence of CHABs on open water surfaces also depends on environmental influences such as direct and indirect wind effects. For example, field tests revealed that the surface coverage of CHABs can be reduced to half within an hour at wind speeds of 0.5 m/s.Because our findings indicated that blooming involves surface display of cyanobacteria essentially presenting as a two-dimensional plane under defined conditions, the use of surface imagery to quantify CHABs was justified. This is particularly important in light of the fact that traditional detection methods do not provide accurate distribution information. Nor do they portray CHABs events in a real-time manner due to limitations in on-demand surveillance and delays between sample time and analyzed results. Therefore, a new CHAB detection method using small unmanned aerial systems with consumer-grade cameras was developed at a maximum detection altitude of 80 m. When cyanobacteria were floating on the surface, CHABs detection through RGB band cameras and spectral enhancement techniques was efficient and accurate. Small unmanned aerial systems were capable of providing coverage up to 1 km² per mission and the short intervals between sampling and results (approx. 2 h) allowed for the rapid analysis of data and for implementing follow-up monitoring or treatments. This method is very cost-effective at an estimate of as low as $100 CAD per mission with an average cyanobacterial detection accuracy of 86%. Thus, it is a good candidate method to fill the urgent need for CHABs detection, providing cost effective, rapid, and accurate information to improve risk management at a local level as well as to help quickly allocate resources for purposes of mitigation.     

Comparison of leaf area index inversion for grassland vegetation through remotely sensed spectra by unmanned aerial vehicle and field-based spectroradiometer

Aims Remote sensing technology has been proved useful in mapping grassland vegetation properties. Spectral features of vegetation cover can be recorded by optical sensors on board of different platforms. With increasing popularity of applying unmanned aerial vehicle (UAV) to mapping plant cover, the study aims to investigate the possible applications and potential issues related to mapping leaf area index (LAI) through integration of remote sensing imagery collected by multiple sensors.