2,693 research outputs found
Increasing persistence in undergraduate science majors: a model for institutional support of underrepresented students.
The 6-yr degree-completion rate of undergraduate science, technology, engineering, and mathematics (STEM) majors at U.S. colleges and universities is less than 40%. Persistence among women and underrepresented minorities (URMs), including African-American, Latino/a, Native American, and Pacific Islander students, is even more troubling, as these students leave STEM majors at significantly higher rates than their non-URM peers. This study utilizes a matched comparison group design to examine the academic achievement and persistence of students enrolled in the Program for Excellence in Education and Research in the Sciences (PEERS), an academic support program at the University of California, Los Angeles, for first- and second-year science majors from underrepresented backgrounds. Results indicate that PEERS students, on average, earned higher grades in most "gatekeeper" chemistry and math courses, had a higher cumulative grade point average, completed more science courses, and persisted in a science major at significantly higher rates than the comparison group. With its holistic approach focused on academics, counseling, creating a supportive community, and exposure to research, the PEERS program serves as an excellent model for universities interested in and committed to improving persistence of underrepresented science majors and closing the achievement gap
A genetic assessment of parentage in the blackspot sergeant damselfish, Abudefduf sordidus (Pisces: Pomacentridae)
Microsatellite markers were used to investigate the reproductive behavior of the damselfish Abudefduf sordidus at Johnston Atoll, Central Pacific Ocean. Genetic results indicated that ten males maintained guardianship over their nest territories for up to nine nest cycles during a 3.5 month period. Genotypes of 1025 offspring sampled from 68 nests (composed of 129 clutches) were consistent with 95% of the offspring being sired by the guardian male. Offspring lacking paternal alleles at two or more loci were found in 19 clutches, indicating that reproductive parasitism and subsequent alloparental care occurred. Reconstructed maternal genotypes allowed the identification of a minimum of 74 different females that spawned with these ten territorial males. Males were polygynous, mating with multiple females within and between cycles. Genetic data from nests, which consisted of up to four clutches during a reproductive cycle, indicated that each clutch usually had only one maternal contributor and that different clutches each had different dams. Females displayed sequential polyandry spawning with one male within a cycle but switched males in subsequent spawning cycles. These results highlight new findings regarding male parasitic spawning, polygyny, and sequential polyandry in a marine fish with exclusive male paternal care.Published versio
Unified Internet Messaging
As telephony services, mobile services and internet services continue to converge, the prospect of providing Unified Messaging and even Unified Communications becomes increasingly achievable. This paper discusses the growing importance of IP-based networks to Unified Messaging developments and examines some of the key services and protocols that are likely to make Unified Messaging more widely available. In this initial paper, we limit ourselves initially to the unification of text-based messaging using SMS and Email. The approach we make is based on the existing Internet Email framework but will take cognisance of the need to add voice and other non-text based messaging and communications at a later stage. Ultimately, the research project aims to build a working prototype of a generic messaging model that works for both non realtime and real-time communications. This model will provide a framework into which existing and future messaging protocols can be plugged. This paper originated from an applied research project which examined the integration possibilities for various messaging and communications protocol
THE INFLUENCE OF SALMONELLA IN PIGS PRE-HARVEST ON SALMONELLA HUMAN HEALTH COSTS AND RISK FROM PORK
Salmonellosis in people is a costly disease, much of it occurring because of food associated exposure. We develop a farm-to-fork model which estimates the pork associated Salmonella risk and human health costs. This analysis focuses on the components of the pork production chain up to the point of producing a chilled pork carcass. Sensitivity and scenario analysis show that changes that occur in Salmonella status during processing are substantially more important for human health risk and have a higher benefit/cost ratio for application of strategies that control Salmonella compared with on-farm strategies.Food Consumption/Nutrition/Food Safety,
Seeking Gauge Bileptons in Linear Colliders
A promising direction to find physics beyond the standard model is to look
for violation of conservation. In particular the process with the exchange of a gauge bilepton has a striking
signal without background and is predicted in the most economical model to have
a cross-section an order of magnitude higher than previous estimates.Comment: 4 pages LaTeX and 5 postscript figure
Diet-induced obesity impairs mammary development and lactogenesis in murine mammary gland
We have developed a mouse model of diet-induced obesity that shows numerous abnormalities relating to mammary gland function. Animals ate 40% more calories when offered a high-fat diet and gained weight at three times the rate of controls. They exhibited reduced conception rates, increased peripartum pup mortality, and impaired lactogenesis. The impairment of lactogenesis involved lipid accumulation in the secretory epithelial cells indicative of an absence of copius milk secretion. Expression of mRNAs for -casein, whey acid protein, and -lactalbumin were all decreased immediately postpartum but recovered as lactation was established over 2β3 days. Expression of acetyl-CoA carboxylase (ACC)- mRNA was also decreased at parturition as was the total enzyme activity, although there was a compensatory increase in the proportion in the active state. By day 10 of lactation, the proportion of ACC in the active state was also decreased in obese animals, indicative of suppression of de novo fatty acid synthesis resulting from the supply of preformed fatty acids in the diet. Although obese animals consumed more calories in the nonpregnant and early pregnant states, they showed a marked depression in fat intake around day 9 of pregnancy before food intake recovered in later pregnancy. Food intake increased dramatically in both lean and obese animals during lactation although total calories consumed were identical in both groups. Thus, despite access to high-energy diets, the obese animals mobilized even more adipose tissue during lactation than their lean counterparts. Obese animals also exhibited marked abnormalities in alveolar development of the mammary gland, which may partially explain the delay in differentiation evident during lactogenesis
Designing a graphical user interface for a bilateral negotiation support system
Graphical User Interfaces (GUI) are quickly becoming the standard operating environment for most software programs and operating systems. Ease of use, rapid learning and the ability to retain complex task sequences and operations are some of the advantages attributed to this type of interface. When properly implemented the GUI can provide a natural interaction between the user and the computer. Initial acceptance and continued use of any program can be greatly enhanced by proper design of this interface. It is expected that this trend toward visual representation of a task's objects and actions will be more fully developed and expanded in future years. This thesis explored the principles of interface design with particular attention given to the specific characteristics associated with GUI design. Unique design concepts associated with Negotiation Support Systems were also considered. These design techniques and principles were then applied in the analysis and design of the graphical user interface for a Bilateral Negotiation Support System based on multiple attribute utility theory. The program was written in Microsoft Visual Basic for use under the Microsoft Windows 3.0 operating environment.http://archive.org/details/designinggraphic1094538555Lieutenant Commander, United States Naval ReserveApproved for public release; distribution is unlimited
Comparative Phylogeography in Fijian Coral Reef Fishes: A Multi-Taxa Approach towards Marine Reserve Design
Delineating barriers to connectivity is important in marine reserve design as they describe the strength and number of connections among a reserveβs constituent parts, and ultimately help characterize the resilience of the system to perturbations at each node. Here we demonstrate the utility of multi-taxa phylogeography in the design of a system of marine protected areas within Fiji. Gathering mtDNA control region data from five species of coral reef fish in five genera and two families, we find a range of population structure patterns, from those experiencing little (Chrysiptera talboti, Halichoeres hortulanus, and Pomacentrus maafu), to moderate (Amphiprion barberi, Wst = 0.14 and Amblyglyphidodon orbicularis Wst = 0.05) barriers to dispersal. Furthermore estimates of gene flow over ecological time scales suggest speciesspecific, asymmetric migration among the regions within Fiji. The diversity among species-specific results underscores the limitations of generalizing from single-taxon studies, including the inability to differentiate between a species-specific result and a replication of concordant phylogeographic patterns, and suggests that greater taxonomic coverage results in greater resolution of community dynamics within Fiji. Our results indicate that the Fijian reefs should not be managed as a single unit, and that closely related species can express dramatically different levels of population connectivity
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