Djungarian hamsters (Phodopus sungorus) are not susceptible to stimulating effects of 6-methoxy-2-benzoxazolinone on reproductive organs

The secondary plant metabolite 6-methoxy-2-benzoxazolinone (6-MBOA) is abundant in vegetative parts of monocotyledons emerging in spring. This grazing protective has been shown to promote gonadal growth and, thus enable precise alignment of reproductive activity with favorable environmental conditions in a variety of seasonally breeding rodent species. Feeding and breeding ecology make the Djungarian hamster (Phodopus sungorus) a potential candidate using 6-MBOA as an acute environmental cue to optimize reproductive timing when photorefractoriness induces reproductive recrudescence. Therefore, four different experiments were designed to examine whether the hamsters’ reproductive organs are responsive to oral 6-MBOA administration under different photoperiodic conditions. Only under a long photoperiod, we found a slight increase in uterine weights. In a short photoperiod, 6-MBOA-treated hamsters showed a slight body weight gain without a change in uterine weights. However, these marginal effects are likely not to be of ecophysiological significance for reproductive timing. The results are in agreement with the common view that the annual changes in photoperiod length are not only the predominant environmental cue for Djungarian hamsters, but are also sufficient to synchronize reproductive efforts with favorable breeding conditions in highly predictable climates like the continental Asian steppes.     

Biomechanics of Pediatric Cervical Spine: Compression,Flexion and Extension Responses

The objective of the present study was to develop three separate age-specific one, three, and six year old pediatric human cervical spine (C4-CS-C6) three-dimensional nonlinear finite element models and to quantify the biomechanical responses. The adult model was modified to create one, three, and six year old pediatric spines by incorporating the local geometrical and material characteristics of the developmental anatomy. The adult human cervical spine model was constructed from close-up computed tomography sections and sequential anatomic cryomicrotome sections, and validated with experimental data. The biomechanical responses were compared with the adult human cervical spine behavior under different loading modes using three approaches. Approach 1: using pure overall structural scaling (reduce size) of the adult model. Approach 2: using three separate age-specific pediatric models incorporating local component geometrical and material property changes. Approach 3: applying the overall structural scaling to the above three pediatric models. All pediatric structures were consistently more flexible than the adult spine under all loading modes. However, responses obtained using the pure overall structural scaling (Approach 1) increased the flexibilities slightly. In contrast, the inclusion of local component geometrical and material property changes to create the three individual pediatric cervical spine models (Approach 2) produced significantly higher changes in the flexibilities under all loading modes. When overall structural scaling effects were added to the three pediatric models (Approach 3), the increase was not considerably higher. White the one year old pediatric model was the most flexible followed by the three and six year old models in flexion and extension, the three year old pediatric model was the most flexible under compression followed by the six and one year old models. The differing biomechanical responses among different pediatric groups were ascribed to the individual developmental anatomical features. The present findings of significant increase in biomechanical response due to local geometry and material property changes emphasize the need to consider the developmental anatomical features in the pediatric structures to better predict their biomechanical behavior.     

A conceptual model of the role of complex science in local authority consultations about air quality management

Abstract

There exists a clear imperative across the EU and within the UK towards the enhanced integration of community knowledge in environmental and health decision-making processes. The underlying social force that underpins this dynamic is the drive for a more accountable, transparent and publicly acceptable decision-making arena. However, relatively little research has been undertaken on the evaluation of local air quality management consultation in particular. In this context, the paper presents an evaluation of evidence resulting from questionnaire survey and case study research undertaken in the first round of the statutory process of local air quality management (LAQM), in which local authorities are required to consult on their air quality findings and intentions. We suggest that local authority perceptions of the relative abilities of differing stakeholders' grasp of air quality science, the process that translates that science into policy, and the institutional and organizational status of stakeholders (i.e. whether they are statutory or non-statutory stakeholders) may tend to transitively determine the choice of consultation methods used, the communication strategies chosen and the relative integration of stakeholder feedback into the LAQM decision-making process. In order to interrogate this potentially problematic chain of risk communication events, a preliminary conceptual model has been developed to enable the interrogation of the pathways through, and the obstacles to, the translation of air quality knowledge. The task is to unveil the sequential chains of association that comprise the LAQM risk communication process.     

Waste Management and Climate Change

Waste management has at least five types of impacts on climate change, attributable to: (1) landfill methane emissions; (2) reduction in industrial energy use and emissions due to recycling and waste reduction; (3) energy recovery from waste; (4) carbon sequestration in forests due to decreased demand for virgin paper; and (5) energy used in long-distance transport of waste: A recent USEPA study provides estimates of overall per-tonne greenhouse gas reductions due to recycling. Plausible calculations using these estimates suggest that countries such as the US or Australia could realise substantial greenhouse gas reductions through increased recycling, particularly of paper.     

Synchrotron micro-scale measurement of metal distributions in Phragmites australis and Typha latifolia root tissue from an urban brownfield site

Liberty State Park in New Jersey,USA,is a "brownfield" site containing various levels of contaminants.To investigate metal uptake and distributions in plants on the brownfield site,Phragmites australis and Typha latifolia were collected in Liberty State Park during the growing season(May–September)in 2011 at two sites with the high and low metal loads,respectively.The objective of this study was to understand the metal(Fe,Mn,Cu,Pb and Zn)concentration and spatial distributions in P.australis and T.latifolia root systems with micro-meter scale resolution using synchrotron X-ray microfluorescence(μXRF)and synchrotron X-ray computed microtomography(μCMT)techniques.The root structure measurement by synchrotron μCMT showed that high X-ray attenuation substance appeared in the epidermis.Synchrotron μXRF measurement showed that metal concentrations and distributions in the root cross-section between epidermis and vascular tissue were statistically different.Significant correlations were found between metals(Cu,Mn,Pb and Zn)and Fe in the epidermis,implying that metals were scavenged by Fe oxides.The results from this study suggest that the expression of metal transport and accumulation within the root systems may be element specific.The information derived from this study can improve our current knowledge of the wetland plant ecological function in brownfield remediation.     

One year in the life of <Emphasis Type="Italic">Bufo punctatus</Emphasis>: annual patterns of body temperature in a free-ranging desert anuran

The Mojave Desert is characterized by hot dry summers and cold winters. The red-spotted toad (Bufo (Anaxyrus) punctatus) is the predominant anuran species; yet little is known of their thermal histories and strategies to avoid temperature extremes. We measured body temperature (T(b)) in free-ranging adult toads across all four seasons of a year using implanted data loggers. There is marked individual variation in the temperatures experienced by these toads. As expected, toads generally escape extreme seasonal and diel temperature fluctuations. However, our data demonstrate a much wider estimated T(b) range than was previously assumed. Though often for short periods, red-spotted toads do experience T(b) as low as 3.1 degrees C and as high as 39.1 degrees C. All animals showed periods of prolonged thermal stability in cooler months and wider diel oscillations in warmer months. Red-spotted toad thermal history is likely a function of site choice; the exploitation of different refuges results in diverse thermal experiences. These data represent the most complete record of thermal experiences for a desert anuran and reveal greater extremes in body temperature than previously suggested.     

Chloride - a precursor in the formation of volatile organochlorines by forest plants?

Two plants, a fern (Athyrium filix-femina) and a moss (Polytrichum commune Hedw.), both commonly occurring in Northern Temperate forests, were exposed in a laboratory study to a solution of (36)Cl-chloride. The uptake of (36)Cl-chloride by the plants was investigated and the emission of volatile chlorine 36 by the plants was determined. Furthermore, speciation of the emitted volatile organochlorine compounds (VOCls) was investigated. For the fern and the moss a rapid uptake of (36)Cl-chloride was observed within a 1-h exposure period. The uptake rates for the fern and the moss, respectively, were 16 mug (36)Cl-chloride g(-1) fresh weight (FW) h(-1) and 3.0 mug (36)Cl-chloride g(-1) FW h(-1), respectively. The study also suggested that after uptake by the plants (36)Cl-chloride is incorporated into VOCls, which were emitted by the plants into the atmosphere. Speciation analysis of the VOCls revealed the emission of chloroform, tetrachloromethane and 1,1,1-trichloroethane.     

Propolis efficacy on SARS-COV viruses: a review on antimicrobial activities and molecular simulations

Environmental Science and Pollution Research - This current study review provides a brief review of a natural bee product known as propolis and its relevance toward combating SARS-CoV viruses....     

北京大气PM2.5中铅的同位素测定和来源研究

用石英滤膜连续采集北京2003-02～2003-03的12个PM_2.5样品,进行无机多元素、OC、EC和铅同位素丰度比的分析测定.对样品进行聚类分析,结合气象信息讨论了分组结果,描述了2003年春北京市的2个大气铅污染过程.2个污染过程均表现出铅含量高,²⁰⁶Pb/²⁰⁷Pb丰度比低的特点.Al、Ca、K等地壳元素的含量与Pb的含量负相关,表明土壤尘对铅的贡献不大.比较Pb、As、Zn、Se和Al、Ca等地壳元素含量的相关性,2个铅污染过程是由有色冶金排放和燃煤排放共同主导的.而02-28～03-02的铅污染过程中,燃煤排放贡献增大,有色冶金排放贡献下降.结果表明,汽油无铅化以后,北京市春季大气颗粒物中的铅主要来源于有色冶金排放与燃煤排放.     

Nitrogen cycling during seven years of atmospheric CO2 enrichment in a scrub oak woodland

Experimentally increasing atmospheric CO2 often stimulates plant growth and ecosystem carbon (C) uptake. Biogeochemical theory predicts that these initial responses will immobilize nitrogen (N) in plant biomass and soil organic matter, causing N availability to plants to decline, and reducing the long-term CO2-stimulation of C storage in N limited ecosystems. While many experiments have examined changes in N cycling in response to elevated CO2, empirical tests of this theoretical prediction are scarce. During seven years of postfire recovery in a scrub oak ecosystem, elevated CO2 initially increased plant N accumulation and plant uptake of tracer 15N, peaking after four years of CO2 enrichment. Between years four and seven, these responses to CO2 declined. Elevated CO2 also increased N and tracer 15N accumulation in the O horizon, and reduced 15N recovery in underlying mineral soil. These responses are consistent with progressive N limitation: the initial CO2 stimulation of plant growth immobilized N in plant biomass and in the O horizon, progressively reducing N availability to plants. Litterfall production (one measure of aboveground primary productivity) increased initially in response to elevated CO2, but the CO2 stimulation declined during years five through seven, concurrent with the accumulation of N in the O horizon and the apparent restriction of plant N availability. Yet, at the level of aboveground plant biomass (estimated by allometry), progressive N limitation was less apparent, initially because of increased N acquisition from soil and later because of reduced N concentration in biomass as N availability declined. Over this seven-year period, elevated CO2 caused a redistribution of N within the ecosystem, from mineral soils, to plants, to surface organic matter. In N limited ecosystems, such changes in N cycling are likely to reduce the response of plant production to elevated CO2.