Sex difference in polybrominated diphenyl ether concentrations of walleyes

Polybrominated diphenyl ether (PBDE) concentrations were determined for mature male and mature female walleyes (Sander vitreus) sampled from the Saginaw Bay population during 2007. PBDE concentrations in prey fish caught in the Saginaw River, the primary tributary to Saginaw Bay, and in Saginaw Bay during 2005 and 2007 also were determined. Mature male and mature female walleyes averaged 70.3 ng/g and 24.8 ng/g, respectively, in ΣPBDE, which was equal to the sum of concentrations of six PBDE congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, and BDE-154). This sex difference was likely due to males spending more time in the Saginaw River system than females. Prey fish captured in the Saginaw River were roughly ten times higher in ΣPBDE than those caught in Saginaw Bay. BDE-47 was the predominant congener in both walleyes and prey fish, and this congener contributed about 50%, on average, to ΣPBDE. Congener profiles differed significantly between the two sexes of walleyes. In contrast, congener profiles of the prey fish did not differ significantly between the river-caught fish and the bay-caught fish. One plausible explanation for these congener profile results was that net trophic transfer efficiencies of PBDEs to walleyes from their prey were similar for all congeners except BDE-28, and that diet composition differed between the two sexes of walleyes.     

Discovery of the Asiatic Clam,Corbicula Fluminea,in Lake Michigan

Ten live specimens of the Asiatic clam, Corbicula fluminea (Müller) were collected 22 November 1983 in southeastern Lake Michigan offshore from the J. H. Campbell Power Plant. The site is 7.6 m deep with a substrate of coarse sand and gravel. This represents the second record of Corbicula from the Laurentian Great Lakes and the first from Lake Michigan.     

Big data and smart cities: a public sector organizational learning perspective

Public sector organizations (city authorities) have begun to explore ways to exploit big data to provide smarter solutions for cities. The way organizations learn to use new forms of technology has been widely researched. However, many public sector organisations have found themselves in new territory in trying to deploy and integrate this new form of technology (big data) to another fast moving and relatively new concept (smart city). This paper is a cross-sectional scoping study—from two UK smart city initiatives—on the learning processes experienced by elite (top management) stakeholders in the advent and adoption of these two novel concepts. The findings are an experiential narrative account on learning to exploit big data to address issues by developing solutions through smart city initiatives. The findings revealed a set of moves in relation to the exploration and exploitation of big data through smart city initiatives: (a) knowledge finding; (b) knowledge reframing; (c) inter-organization collaborations and (d) ex-post evaluations. Even though this is a time-sensitive scoping study it gives an account on a current state-of-play on the use of big data in public sector organizations for creating smarter cities. This study has implications for practitioners in the smart city domain and contributes to academia by operationalizing and adapting Crossan et al’s (Acad Manag Rev 24(3): 522–537, 1999) 4I model on organizational learning.     

Land‐use impacts on small‐scale Mpologoma wetland fishery,eastern Uganda: A socio‐economic perspective

Small‐scale fisheries in developing countries are characterized by uncertain futures attributable to ever‐increasing pressures on wetland resources. Data on the interconnectivity between wetland fishery, land‐use changes and the socio‐economic situation in the Mpologoma wetland, Uganda, were obtained through interviews and structured questionnaire surveys at sampling sites exhibiting differing different levels of environmental disturbance (ranging from less disturbed to highly disturbed). Rice production was the major economic activity at the highly disturbed sites, while maize production was the major activity at the less‐disturbed sites. Of the secondary activities, the Clarias gariepinus (Burchell, 1815) and Protopterus aethiopicus (Heckel, 1851) fishery was more important at the less‐disturbed sites. The high daily fish sale income ranging from US$ 8 to 12 and the high‐percentage (52%) catch preference of all large wetland fish species were observed for the less‐disturbed sites. A high percentage of respondents from the area of the less‐disturbed sites had higher annual incomes, resulting in more accumulated wealth than for the highly disturbed Nsango site, whose fishery was affected by large‐scale rice schemes. The overall socio‐economic impact of the small‐scale fishery, based on the data regarding the number of fishermen and their dependents, and the income from fish sales and other wetland activities, was low, with differences between sites being attributed to the level of wetland disturbance. The Mpologoma wetland is threatened by overexploitation of its fisheries services, but also overlooked and undervalued by policymakers because of inadequate fisheries statistics. Thus, the information derived from this study will facilitate the formulation and design of riverine wetland‐specific and small‐scale fisheries management strategies.     

用家务活换取性福

最近段时间,以《XX勿扰》为代表的各类相亲节目在国内彻底地火了一把,除了部分雷人的炒作和噱头外。可以发现其实大部分人的婚恋观还是相当实在的,特别是很多人都把家务活作为一个衡量对方的重要指标。     

Dehydroepiandrosterone alters lipid profiles in Zucker rats

High free fatty acid (FFA) levels are common in obesity and in diseases such as diabetes that are associated with the obese state. Dehydroepiandrosterone (DHEA) decreases dietary fat consumption, body fat content, and insulin levels in the obese Zucker rat (ZR), a genetic model of human youth-onset obesity and type 2 diabetes mellitus. This study was conducted to investigate the effects of DHEA on lean and obese ZR serum, adipose, and hepatic tissue fatty acid (FA) profiles and serum FFA levels. Because DHEA is known to decrease fat consumption and body fat, we postulate that DHEA may also alter FA profiles and FFA levels of the obese ZR such that they more closely resemble the profiles and levels of their lean siblings. In this study there was a DHEA and a pair-fed (PF) group (n=6) for 12 lean and 12 obese ZR. The diet of the treatment groups was supplemented with 0.6% DHEA, and PF groups were given the same average calories consumed by their corresponding DHEA group for 30 d. Fasted animals were sacrificed, and FA profiles and FFA levels were measured. Serum FFA levels were higher in obese (∼1 mmol/L) compared to lean rats (∼0.6 mmol/L). After 30 d of DHEA treatment, FFA levels were lower (P<0.05) in both lean and obese groups. Although several significant differences in FA profile of serum, hepatic, and adipose lipid components were observed between lean and obese ZR, DHEA-related changes were only observed in the serum phospholipid (PL) and liver PL and triglyceride fractions. The slight but significant decrease in serum FFA levels may be reflected by changes in serum PL FA profiles. Specific hepatic FA profile alterations may be related to DHEA's known effects in inducing hepatic peroxisomes. We speculate that such FA changes may give insight into a mechanism for the action of DHEA.     

轮胎与路面面接触包容特性建模

在轮胎线性包容模型的基础上，把轮胎与路面的接触描述为面接触过程，建立轮胎包容特性的计算模型．     

Scrutinizing Design Principles toward Efficient,Long‐Term Stable Green Light‐Emitting Electrochemical Cells

Enhancing the efficiency and lifetime of light emitting electrochemical cells (LEC) is the most important challenge on the way to energy efficient lighting devices of the future. To avail this, emissive Ir(III) complexes with fluoro‐substituted cyclometallated ligands and electron donating groups (methyl and tert ‐butyl)‐substituted diimine ancillary (N^{^}N) ligands and their associated LEC devices are studied. Four different complexes of general composition [Ir(4ppy)₂(N^{^}N)][PF₆] (4Fppy = 2‐(4‐fluorophenyl)pyridine) with the N^{^}N ligand being either 2,2′‐bipyridine ( 1 ), 4.4′‐dimethyl‐2,2′‐bipyridine ( 2 ), 5.5′‐dimethyl‐2,2′‐bipyridine ( 3 ), or 4.4′‐di‐tert ‐butyl‐2,2′‐bipyridine ( 4 ) are synthesized and characterized. All complexes emit in the green region of light with emission maxima of 529–547 nm and photoluminescence quantum yields in the range of 50.6%–59.9%. LECs for electroluminescence studies are fabricated based on these complexes. The LEC based on ( 1 ) driven under pulsed current mode demonstrated the best performance, reaching a maximum luminance of 1605 cd m^?2 resulting in 16 cd A^?1 and 8.6 lm W^?1 for current and power efficiency, respectively, and device lifetime of 668 h. Compared to this, LECs based on ( 3 ) and ( 4 ) perform lower, with luminance and lifetime of 1314 cd m^?2, 45.7 h and 1193 cd m^?2, 54.9 h, respectively. Interestingly, in contrast to common belief, the fluorine content of the Ir‐iTMCs does not adversely affect the LEC performance, but rather electron donating substituents on the N^{^}N ligands are found to dramatically reduce both performance and stability of the green LECs. In light of this, design concepts for green light emitting electrochemical devices have to be reconsidered.     

碳纳米管纱在应力下的压阻效应:现象和影响因素(英文)

碳纳米管因机械应力敏感特性而成为传感器的理想材料。单原子层厚度的石墨烯片卷曲而成的单壁碳纳米管具有大约1 nm的管径。碳纳米管纺丝形成纱,使其能够用于结构组份中。本文研究了碳纳米管纱的几何尺寸、力学性能和准静态应力加载速率对其压阻效应的影响。应力加载速率影响碳纳米管纱的失效机理和机电特性。高应力加载速率导致拉伸强度的增加和正压阻效应,而低应力加载速率引起较高的应力失效与负压阻效应。碳纳米管纱的压阻传感器系数随应力加载速率基本不变,但其对于应力水平和碳纳米管纱的几何尺寸具有高度依赖性。作为传感器所需的线性压阻关系在高应力加载速率下相关系数为0.995,而在低应力加载速率下相关系数只有0.832。