两步回归法研究空气污染与儿童呼吸病症率的关系

通过两步回归法对空气污染与儿童呼吸病症发生率之间的关系进行了研究.结果表明,颗粒物与大部分儿童呼吸病症发生率之间存在显著的正相关关系,SO₂与儿童感冒时气喘有着显著的正相关关联,NO_X与儿童未感冒时气喘有显著的正相关关联.两种回归方法的结果基本一致.其中的混合线性模型不但在城市间发现这些正相关关系,而且在城市内的城郊区之间也发现了正相关关联.本文还给出了暴露在各种空气污染物下儿童呼吸病症发生率的比数比(OR).     

Designing environmental monitoring networks to measure extremes

This paper discusses challenges arising in the design of networks for monitoring extreme values over the domain of a random environmental space-time field {X _ij } i = 1, . . . , I denoting site and j = 1, . . . denoting time (e.g. hour). The field of extremes for time span r over site domain i = 1, . . . ,I is given by \(\{Y_{i(r+1)}=\max_{j=k}^{k+n-1} X_{ij}\}\) for k = 1 + rn, r = 0, . . . ,. Such networks must not only measure extremes at the monitored sites but also enable their prediction at the non-monitored ones. Designing such a network poses special challenges that do not seem to have been generally recognized. One of these problems is the loss of spatial dependence between site responses in going from the environmental process to the field of extremes it generates. In particular we show empirically that the intersite covariance Cov(Y _i(r+1),Y _i′(r+1)) can generally decline toward zero as r increases, for site pairs i ≠ i′. Thus the measured extreme values may not predict the unmeasured ones very precisely. Consequently high levels of pollution exposure of a sensitive group (e.g. school children) located between monitored sites may be overlooked. This potential deficiency raises concerns about the adequacy of air pollution monitoring networks whose primary role is the detection of noncompliance with air quality standards based on extremes designed to protect human health. The need to monitor for noncompliance and thereby protect human health, points to other issues. How well do networks designed to monitor the field monitor their fields of extremes? What criterion should be used to select prospective monitoring sites when setting up or adding to a network? As the paper demonstrates by assessing an existing network, the answer to the first question is not well, at least in the case considered. To the second, the paper suggests a variety of plausible answers but shows through a simulation study, that they can lead to different optimum designs. The paper offers an approach that circumvents the dilemma posed by the answer to the second question. That approach models the field of extremes (suitably transformed) by a multivariate Gaussian-Inverse Wishart hierarchical Bayesian distribution. The adequacy of this model is empirically assessed in an application by finding the relative coverage frequency of the predictive credibility ellipsoid implied by its posterior distribution. The favorable results obtained suggest this posterior adequately describes that (transformed) field. Hence it can form the basis for designing an appropriate network. Its use is demonstrated by a hypothetical extension of an existing monitoring network. That foundation in turn enables a network to be designed of sufficient density (relative to cost) to serve its regulatory purpose.     

Fluid bed gasification – Plasma converter process generating energy from solid waste: Experimental assessment of sulphur species

Often perceived as a Cinderella material, there is growing appreciation for solid waste as a renewable content thermal process feed. Nonetheless, research on solid waste gasification and sulphur mechanisms in particular is lacking. This paper presents results from two related experiments on a novel two stage gasification process, at demonstration scale, using a sulphur-enriched wood pellet feed.Notable SO₂ and relatively low COS levels (before gas cleaning) were interesting features of the trials, and not normally expected under reducing gasification conditions. Analysis suggests that localised oxygen rich regions within the fluid bed played a role in SO₂’s generation. The response of COS to sulphur in the feed was quite prompt, whereas SO₂ was more delayed. It is proposed that the bed material sequestered sulphur from the feed, later aiding SO₂ generation. The more reducing gas phase regions above the bed would have facilitated COS – hence its faster response. These results provide a useful insight, with further analysis on a suite of performed experiments underway, along with thermodynamic modelling.     

Microscope and spectacle: On the complexities of using new visual technologies to communicate about wildlife conservation

Wildlife conservation-related organisations increasingly employ new visual technologies in their science communication and public engagement efforts. Here, we examine the use of such technologies for wildlife conservation campaigns. We obtained empirical data from four UK-based organisations through semi-structured interviews and participant observation. Visual technologies were used to provide the knowledge and generate the emotional responses perceived by organisations as being necessary for motivating a sense of caring about wildlife. We term these two aspects ‘microscope’ and ‘spectacle’, metaphorical concepts denoting the duality through which these technologies speak to both the cognitive and the emotional. As conservation relies on public support, organisations have to be seen to deliver information that is not only sufficiently detailed and scientifically credible but also spectacular enough to capture public interest. Our investigation showed that balancing science and entertainment is a difficult undertaking for wildlife-related organisations as there are perceived risks of contriving experiences of nature and obscuring conservation aims.     

Simple Modeling Tool for Reconstructing Source History Using High Resolution Contaminant Profiles From Low‐k Zones

An innovative but simple analytical modeling tool for reconstructing contaminant concentration versus time trends (i.e., “source history”) for a site using high‐resolution contaminant profiles from low permeability (low‐k) zones was developed and tested. Migration of contaminants into low‐k zones via diffusion (and possibly slow advection) produce concentration versus depth profiles that can be used to understand temporal concentration trends at the interface with overlying transmissive zones, including evidence of attenuation over time due to source decay. A simple transport‐based spreadsheet tool for generating source history estimates fit to the profiles was developed and applied to published soil concentration versus depth data from five distinct areas of four different sites contaminated with chlorinated ethenes. Using the root mean square error as an optimization metric, strong fits between measured and model‐predicted soil data were obtained in the majority of cases using site‐specific values for input parameters. In general, significant improvements could not be obtained by varying these parameters. As a result, the source history estimates generated by the tool were similar to those that had already been generated using more intensive analytical or numerical inverse modeling approaches. This included confirmation of constant source histories at locations where dense nonaqueous‐phase liquid was present (or suspected to be present), and declining source histories for locations where source isolation and/or attenuation had occurred. The advantage of the modeling tool described here is that it provides a simpler yet more dynamic method for understanding source behavior over time than existing approaches. ©2015 Wiley Periodicals, Inc.     

All-in-one whole exome sequencing strategy with simultaneous copy number variant,single nucleotide variant and absence-of-heterozygosity analysis in fetuses with structural ultrasound anomalies: A 1-year experience

Objective

We performed a 1-year evaluation of a novel strategy of simultaneously analyzing single nucleotide variants (SNVs), copy number variants (CNVs) and copy-number-neutral Absence-of-Heterozygosity from Whole Exome Sequencing (WES) data for prenatal diagnosis of fetuses with ultrasound (US) anomalies and a non-causative QF-PCR result.

Methods

After invasive diagnostics, whole exome parent-offspring trio-sequencing with exome-wide CNV analysis was performed in pregnancies with fetal US anomalies and a non-causative QF-PCR result (WES-CNV). On request, additional SNV-analysis, restricted to (the) requested gene panel(s) only (with the option of whole exome SNV-analysis afterward) was performed simultaneously (WES-CNV/SNV) or as rapid SNV-re-analysis, following a normal CNV analysis.

Results

In total, 415 prenatal samples were included. Following a non-causative QF-PCR result, WES-CNV analysis was initially requested for 74.3% of the chorionic villus (CV) samples and 45% of the amniotic fluid (AF) samples. In case WES-CNV analysis did not reveal a causative aberration, SNV-re-analysis was requested in 41.7% of the CV samples and 17.5% of the AF samples. All initial analyses could be finished within 2 weeks after sampling. For SNV-re-analysis during pregnancy, turn-around-times (TATs) varied between one and 8 days.

Conclusion

We show a highly efficient all-in-one WES-based strategy, with short TATs, and the option of rapid SNV-re-analysis after a normal CNV result.     

Saharan dust episodes and pregnancy

Desert dust is one of the natural contributors to atmospheric particulate matter worldwide. Although particulate pollution has been shown to adversely affect pregnancy, the available evidence on the impact of dust episodes on pregnancy is very scarce. The aim of this study was to evaluate the impact of Saharan dust episodes on pregnancy complications (preeclampsia and bacteriuria) and outcomes (birth weight and gestational age at delivery). This study was based on a cohort of births (N = 3565) that occurred in a major university hospital in Barcelona during 2003-2005. To determine Saharan dust episodes, we developed a two-stage approach based on meteorological evidence of the presence of Saharan dust cloud over the region and unusually high levels of particulate levels on the ground while taking account of traffic sources. The associations between the number of Saharan dust episodes during whole pregnancy as well as each pregnancy trimester and pregnancy complications and outcomes were analysed. There were 152 days (out of 838 days) with Saharan dust cloud over the region from which 45 days were determined as episodic days. We did not observe any statistically significant harmful effect of Saharan dust episodes on our included pregnancy complications and outcomes. However, we observed a small but statistically significant increase in gestational age at delivery in association with the number of episodic days during the third trimester and whole pregnancy (0.8 and 0.5 days respectively). Our findings were not suggestive for any adverse effect of Saharan dust episodes on our included pregnancy complications and outcomes.     

Association patterns of spider monkeys: the influence of ecology and sex on social organization

Summary In this paper I consider how the costs and benefits of group living in spider monkeys (Ateles geoffroyi) vary between troop members. The results suggest that ecological factors set an upper limit to the number of spider monkeys that can associate and still efficiently exploit the available resources. In addition, the needs of the individual appears to influence the type and size of the subgroup it chooses. Adult males band together, travel over a large area, and are frequently sighted near the community's boundary. In contrast, adult females spend more time solitary than males and have association patterns that are strongly influenced by the presence of a dependent infant. Females with dependent infants tend to travel in small subgroups or alone, avoid the boundaries of the community's home range, and exhibit a restricted pattern of use of their range. The results suggest that males may be attempting to locate females with which they can breed, while mothers attempt to protect their infants by avoiding conspecifics and potentially dangerous situations near territorial boundaries.