1,528 research outputs found
An ethnographic study of family, livelihoods and women's everyday lives in Dakar, Senegal
This thesis explores competing meanings of being a woman in Dakar, Senegal. Above all, it is concerned with the relationship between livelihoods â how ordinary Dakarois make ends meet â and womenâs gendered identities. It explores the full spectrum of Dakar womenâs economic activities, all the while keeping the definition of what, precisely, qualifies as âeconomicâ or as âworkâ as open as possible. Distancing itself from approaches that privilege the sexual aspects of gender, this thesis asks what kinds of gendered economic identities emerge in the context of the various roles and relationships that constitute womenâs everyday lives. What do women do that enables people in this society to get by and to secure their day-Ââto-Ââday needs? How are these activities experienced, and what kind of values are they imbued with? Based on three yearsâ fieldwork in low-Ââincome neighbourhoods across the Dakar region, the thesis advances an ethnographic analysis of womenâs roles as wives and girlfriends, sisters and sisters-Ââin-Ââlaw, daughters, mothers and grandmothers, and members of extended family and community networks. It explores womenâs activities as dependents, consumers, providers and informal-Ââsector workers. Together, the chapters shed light on the complexities and contradictions involved in being a woman in this particular part of the world. Building on the ethnographic findings, this thesis argues that it is possible to identify two distinct, even competing conceptions of being a woman in Dakar. One of these can be framed in terms of âmaterialismâ, the other around the emic concept of âmothering workâ. Dakar women, this thesis suggests, draw on both in order to create, defend and challenge the meaning and the value of their everyday experiences
Meiotic recombination and male infertility: from basic science to clinical reality?
Infertility is a common problem that affects approximately 15% of the population. Although many advances have been made in the treatment of infertility, the molecular and genetic causes of male infertility remain largely elusive. This review will present a summary of our current knowledge on the genetic origin of male infertility and the key events of male meiosis. It focuses on chromosome synapsis and meiotic recombination and the problems that arise when errors in these processes occur, specifically meiotic arrest and chromosome aneuploidy, the leading cause of pregnancy loss in humans. In addition, meiosis-specific candidate genes will be discussed, including a discussion on why we have been largely unsuccessful at identifying disease-causing mutations in infertile men. Finally clinical applications of sperm aneuploidy screening will be touched upon along with future prospective clinical tests to better characterize male infertility in a move towards personalized medicine
Ghost of invasion past: legacy effects on community disassembly following eradication of an invasive ecosystem engineer
By changing ecosystem processes and altering the physical landscape, invasive ecosystem engineers can have substantial impacts on ecosystem functions and human economies and may facilitate other non-native species. Eradication programs in terrestrial and aquatic systems aim to reverse the impacts of invasive species and return the system to its pre-invasion conditions. Despite an extensive focus on the impacts of both native and non-native ecosystem engineers, the consequences of removing invasive ecosystem engineers, particularly in coastal ecosystems, are largely unknown. In this study, we quantified changes in a benthic community following the eradication of the invasive ecosystem engineer, hybrid cordgrass Spartina, in San Francisco Bay, California. We used field experimental manipulations to test for persistent effects of both aboveground and belowground structural modifications of the invasive plant on the benthic community. We found significant effects of the invasive plant more than four years following eradication. Experimental modification of the above- vs. belowground structure of this ecosystem engineer revealed taxonomic specific effects resulting in hysteresis in the recovery of the benthic food webs. We found that these legacy effects resulted from two specific mechanisms: (1) delayed breakdown of belowground structures (stems, roots) and (2) persistence of other invasive species whose invasion was facilitated by the ecosystem engineer. Both of these mechanisms are likely to occur in similar systems where belowground structures breakdown more slowly or where other associated long-lived invaders persist. Our work is among the first to quantify the slow rate of change in food web and community processes and the persistent legacy effects of an invasive ecosystem engineer in a coastal ecosystem. We suggest that this delayed transition to pre-invasion conditions could resemble an alternate state that would be misidentified without a sufficient monitoring interval or recovery duration, with consequences for future management and restoration activity planning
Persistent azulene α-carbocations:synthesis from aldehydes, spectroscopic and crystallographic properties
The non-benzenoid aromatic system azulene is sufficiently nucleophilic at C1 that it can react with a protonated aldehyde to form an α-azulenyl alcohol. This in turn may be protonated and undergo loss of water to give an azulene α-carbocation. We report the isolation of such azulenyl cations as salts with non-coordinating anions. The salts have been characterised by NMR, UV/Vis absorption and (in certain cases) X-ray crystallography. Reduction of representative salts to afford azulenyl(aryl) methylenes has been demonstrated.</p
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User's guide for GAPCON-THERMAL-2: A computer program for calculating the thermal behavior of an oxide fuel rod
This report is being published as a user's manual for GAPCON-THERMAL-2 and provides a general description of the code and instructions for its use. The GAPCON-THERMAL-2 code was developed for the Regulatory Staff, NRC, to use as a tool in estimating fuel-cladding gap conductances and fuel stored energy and represents a modification of the GAPCON-THERMAL-1 code. The goal of the modifications was to reduce uncertainties associated with calculating power history and burnup effects and yet retain a relatively flexible and fast running code for parametric studies. 15 references (auth
Oligopolyphenylenevinylene-Conjugated Oligoelectrolyte Membrane Insertion Molecules Selectively Disrupt Cell Envelopes of Gram-Positive Bacteria
The modification of microbial membranes to achieve biotechnological strain improvement with exogenous small molecules, such as oligopolyphenylenevinylene-conjugated oligoelectrolyte (OPV-COE) membrane insertion molecules (MIMs), is an emerging biotechnological field. Little is known about the interactions of OPV-COEs with their target, the bacterial envelope. We studied the toxicity of three previously reported OPV-COEs with a selection of Gram-negative and Gram-positive organisms and demonstrated that Gram-positive bacteria are more sensitive to OPV-COEs than Gram-negative bacteria. Transmission electron microscopy demonstrated that these MIMs disrupt microbial membranes and that this occurred to a much greater degree in Gram-positive organisms. We used a number of mutants to probe the nature of MIM interactions with the microbial envelope but were unable to align the membrane perturbation effects of these compounds to previously reported membrane disruption mechanisms of, for example, cationic antimicrobial peptides. Instead, the data support the notion that OPV-COEs disrupt microbial membranes through a suspected interaction with diphosphatidylglycerol (DPG), a major component of Gram-positive membranes. The integrity of model membranes containing elevated amounts of DPG was disrupted to a greater extent by MIMs than those prepared from Escherichia coli total lipid extracts alone
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Methods for evaluating crown area profiles of forest stands
Canopy architectures of five structurally complex forest stands and three structurally simple forest stands in southwest Oregon and the Willamette Valley, Oregon, were evaluated and quantified through crown area profiles. Mixed conifer and mixed conifer-hardwood stands across a range of sites were sampled for crown widths and heights. Crown width and shape equations were derived and used to quantify the stand crown area at incremental heights above the forest floor. Crown area profiles describe the spatial arrangement of aboveground forest vegetation and the total pore spaces between crowns. Plot by plot profiles were combined to produce vertical and horizontal displays of the stand crown area distribution. In complex stands, the forest space was moderately occupied by crowns from the forest floor up to heights over 30 m, producing uniform distributions of between-crown porosity. The structurally complex stands had between-crown porosity values of 70% to 90% for more than 23 vertical metres of canopy, and they had total between-crown porosities of 86% to 91%. The structurally simple stands had between-crown porosity values of 70% to 90% for less than 8 vertical metres of canopy, and they had total between-crown porosities of 69% to 85%. Variances in crown area indicate that variation in horizontal crown area (within heights) was larger in complex stands than in simple stands, but vertical crown areas (between heights) varied less in complex stands. The study provides a basis for discriminating between canopy architectures and for quantifying the porosity of forest canopies
Stabilization of protein-protein interactions in drug discovery
Introduction: PPIs are involved in every disease and specific modulation of these PPIs with small molecules would significantly improve our prospects of developing therapeutic agents. Both industry and academia have engaged in the identification and use of PPI inhibitors. However in comparison, the opposite strategy of employing small-molecule stabilizers of PPIs is underrepresented in drug discovery. Areas covered: PPI stabilization has not been exploited in a systematic manner. Rather, this concept validated by a number of therapeutically used natural products like rapamycin and paclitaxel has been shown retrospectively to be the basis of the activity of synthetic molecules originating from drug discovery projects among them lenalidomide and tafamidis. Here, the authors cover the growing number of synthetic small-molecule PPI stabilizers to advocate for a stronger consideration of this as a drug discovery approach. Expert opinion: Both the natural products and the growing number of synthetic molecules show that PPI stabilization is a viable strategy for drug discovery. There is certainly a significant challenge to adapt compound libraries, screening techniques and downstream methodologies to identify, characterize and optimize PPI stabilizers, but the examples of molecules reviewed here in our opinion justify these efforts.</p
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