1,777 research outputs found
Various Studies Using 180 Distribution within Paleoclimatic Proxy of Past El Nino/Southern Oscillation Disturbances
El Nino/Southern Oscillation (ENSO) is an excellent example of the interaction between
the ocean and the atmosphere and their combined effect on climate. The need for reliable global records of high-resolution paleoclimatic data has become invaluable for ENS0 experts attempting to develop a means for prediction. Isotopic records from tropical rainfalls, fossilized
marine foraminifera, skeletons of long-lived corals, and ice-cores of tropical ice fields have provided scientists a means by which the length of the climate record can be extended beyond the short period of observed coverage. If these climatic indicators do indeed provide an accurate
reconstruction of climatic conditions within the regions directly affected by ENSO-related events, then perhaps the same techniques can be used to interpret teleconnections related to ENS0 isturbances
Perceptions of Male Versus Female Students Enrolled in Science, Technology, Engineering and Mathematics Courses Regarding Peer Tutoring, a Component for Student Retention
Academic departments in the areas of science, technology, engineering, and mathematics, strive to develop in students the ability to problem solve, analyze, and to critically think about solutions to problems. Academic departments are committed to success, yet retention rates are lower than would be expected for females in science, technology, engineering, and mathematics fields of study, where female students are underrepresented.
The purpose of the study was to explore the perceptions of male and female traditional and nontraditional students who participated in a science, technology, engineering or mathematics STEM course during the spring 2010 semester regarding peer tutoring, and to understand why females are underrepresented and not retained at the same level as males in science, technology, engineering and mathematics STEM courses at the University of North Dakota.
The participants in this quantitative study were students enrolled at the University of North Dakota who voluntarily completed a peer tutoring usage survey. A total of 231 students enrolled in Concepts of Biology (Biol 111), Introduction to Chemistry (Chem 115), Advanced Applications of CADD (Tech 202), Material Properties and Selection (ME 313), and College Algebra (Math 103), completed a survey about their spring 2010 semester.
Five research questions searched for the differences between male and female perceptions regarding peer tutoring, a component of student retention. The independent variable was gender, the dependent variables were the factors regarding peer tutoring: academic preparedness, academic support and cost, and demographics.
Two significant differences were found: (a) females viewed themselves as less prepared for science, technology, engineering, and mathematics courses than did male students, and (b) females were more in favor of the costs of peer tutoring than were male students. These findings support Merton\u27s Self-fulfilling Prophecy Theory. Female students perceived themselves as less prepared for a science, technology, engineering, or mathematics course than male students, and this perception has become a reality, since female students were not retained at the same level as male students in STEM courses
Agencies in Transition: A Report on the Views of the Members of the Federal Senior Executive Service
Many think of leadership transition in government as something that happens only once every four or eight years. While presidential transitions are undoubtedly the largest in scope, leadership transition in government is a constant process. In fact, the average tenure of Senate-confirmed appointees is only 3.3 years, while appointees at executive departments generally spend only 2.8 years in a single post.In a federal government made up of departments and agencies as large and complex as any Fortune 500 company, a strong leadership team is critical to effective governance. Members of the Senior Executive Service (SES) serve as the primary link between political appointees and the broader federal workforce, operating and overseeing nearly every government activity. They play a significant role during leadership transitions, ensuring the continuity of operations within government. Members of the SES are also uniquely positioned to help incoming political leaders build on the positive reforms of the past, and provide insight from lessons learned that can inform success in the future.The National Academy saw the 2008 Presidential transition as an opportunity to draw upon the experience of the SES to find ways to strengthen the partnerships between political and career leaders and build a more efficient and effective government. The results of our study reinforced the critical role played by members of the SES, and revealed that the majority of these career leaders, though experienced in government, were relatively new to managing transition issues as executives.Key FindingsThe findings demonstrated that despite the newness of presidential transitions for most SES, they have a clear understanding about the role they must play in assisting new political appointees, the importance of forming an effective partnership, and their role in the process. At the same time, they wanted help to prepare for those roles, and were eager to engage in training and other activities that would promote success. These SES preferred to receive assistance in preparing for the transition through: (1) policy briefings; (2) discussions with their peers; (3) written materials; and (4) attendance at seminars or training sessions
Agricultural, marketing and trade policies to promote food security in the SADCC region: a research proposal
A research paper on regional co-operation in agricultural marketing in Southern Africa to enhance and promote regional food security.In recent years, the nine member states of SADCC have voiced great interest in expanding intraregional trade as one strategy to increasing food security within the region. The fact that six of the nine countries are landlocked, transport costs are high, and dependence on trade with external countries (including South Africa) is viewed as precarious, has contributed to a sense of urgency which resulted in the funding of prefeasibility and feasibility studies to investigate establishing a regional food security scheme based on local grain reserves,The research supporting the preparation the proceedings papers was financed by the U.S. Agency for International Development, Bureau of Science and Technology; Bureau for Africa; and the Southern Africa Regional Programme
Primary Productivity in Lake Red Haw, Lucas County, Iowa
Primary production studies were conducted on an 83-acre lake in south central Iowa during the summer of 1970 and winter of 1971. Primary productivity was measured using the light dark bottle method. Summer values ranged from 2.74 to 6.25 grams of carbon assimilated/m2/day. This was correlated with water temperature, nitrate nitrogen, ortho phosphates, carbon dioxide, light penetration and plankton populations. Studies were continued during the winter using C14 and scintillation counting methods
Implementation and validation of a CubeSat laser transmitter
The paper presents implementation and validation results for a CubeSat-scale laser transmitter. The master oscillator power amplifier (MOPA) design produces a 1550 nm, 200mW average power optical signal through the use of a directly modulated laser diode and a commercial fiber amplifier. The prototype design produces high-fidelity M-ary pulse position modulated (PPM) waveforms (M=8 to 128), targeting data rates > 10 Mbit/s while meeting a constraining 8W power allocation. We also present the implementation of an avalanche photodiode (APD) receiver with measured transmitter-to-receiver performance within 3 dB of theory. Via loopback, the compact receiver design can provide built-in self-test and calibration capabilities, and supports incremental on-orbit testing of the design
Streptomycin-induced inflammation enhances Escherichia coli gut colonization through nitrate respiration.
UnlabelledTreatment with streptomycin enhances the growth of human commensal Escherichia coli isolates in the mouse intestine, suggesting that the resident microbial community (microbiota) can inhibit the growth of invading microbes, a phenomenon known as "colonization resistance." However, the precise mechanisms by which streptomycin treatment lowers colonization resistance remain obscure. Here we show that streptomycin treatment rendered mice more susceptible to the development of chemically induced colitis, raising the possibility that the antibiotic might lower colonization resistance by changing mucosal immune responses rather than by preventing microbe-microbe interactions. Investigation of the underlying mechanism revealed a mild inflammatory infiltrate in the cecal mucosa of streptomycin-treated mice, which was accompanied by elevated expression of Nos2, the gene that encodes inducible nitric oxide synthase. In turn, this inflammatory response enhanced the luminal growth of E. coli by nitrate respiration in a Nos2-dependent fashion. These data identify low-level intestinal inflammation as one of the factors responsible for the loss of resistance to E. coli colonization after streptomycin treatment.ImportanceOur intestine is host to a complex microbial community that confers benefits by educating the immune system and providing niche protection. Perturbation of intestinal communities by streptomycin treatment lowers "colonization resistance" through unknown mechanisms. Here we show that streptomycin increases the inflammatory tone of the intestinal mucosa, thereby making the bowel more susceptible to dextran sulfate sodium treatment and boosting the Nos2-dependent growth of commensal Escherichia coli by nitrate respiration. These data point to the generation of alternative electron acceptors as a by-product of the inflammatory host response as an important factor responsible for lowering resistance to colonization by facultative anaerobic bacteria such as E. coli
Kinetic analysis of copper(I)/feringa-phosphoramidite catalysed AlEt3 1,4-addition to cyclohex-2-en-1-one
ReactIR studies of mixtures of AlEt3 (A) and cyclohex-2-en-1-one (CX) in Et2O indicate immediate formation of the Lewis acid-base complex (CX.A) at -40 oC (K = 12.0 M-1, ÎGo react -1.1 kcal mol-1). Copper(I) catalysts, derived from pre-catalytic Cu(OAc)2 (up to 5 mol- %) and (R,S,S)-P(binaphtholate){N(CHMePh)2} [Feringaâs ligand (L), up to 5 mol-%] convert CX.A (0.04-0.3 M) into its 1,4-addition product enolate (E) within 2000 sec at -40 oC. Kinetic studies (ReactIR and chiral GC) of CX.A, CX and (R)-3-ethylcyclohexanone (P, the H+ quench product of enolate E) show that the true catalyst is formed in the first 300 sec and this subsequently provides P in 82% ee. This true catalyst converts CX.A to E with a rate law [Cu]1.5[L]0.66[CX.A]1 when [L]/[Cu] †3.5. Above this ligand ratio inhibition by added ligand with order [L]-2.5 is observed. A rate determining step (rds) of Cu3L2(CX.A)2 stoichiometry is shown to be most consistent with the rate law. The presence of the enolate in the active catalyst (Graphical Abstract) best accounts for the reactionâs induction period and molecularity as [E] ⥠[CX.A]. Catalysis proceeds through a âshuttling mechanismâ between two C2 symmetry related ground state intermediates. Each turnover consumes one equivalent of CX.A, expels one molecule of E and forms the new Cu-Et bond needed for the next cycle (Graphic Abstract). The observed ligand (L) inhibition and a non-linear ligand Lee effect on the ee of P are all well simulated by the kinetic model. DFT studies [ÏB97X-D/SRSC] support coordination of CX.A to the groundstate Cu-trimer and its rapid conversion to E
PReS-FINAL-2161: Safety and effectiveness of adalimumab in children with polyarticular juvenile idiopathic arthritis aged 2 to <4 years or >=4 years weighing <15 kg
International audienceEn faisant le tour du monde (Mauritanie, Madagascar, Ăthiopie, Burkina Faso, Cameroun, New-York, Nouvelle-ZĂ©lande, France... ) en passant par lâInternet, cet ouvrage fait le point sur les derniĂšres innovations en matiĂšre de gestion des dĂ©chets. ConsidĂ©rĂ© comme une ressource, le dĂ©chet rĂ©vĂšle enfin sa valeur : il est crĂ©ateur de revenus, de liens sociaux et de nouvelles technologies. Câest pourquoi il devient urgent de structurer son Ă©conomie
A proper understanding of Millikan
Ruth Millikanâs teleological theory of mental content is complex and often misunderstood. This paper motivates and clarifies some of the complexities of the theory, and shows that paying careful attention to its details yields answers to a number of common objections to teleological theories, in particular, the problem of novel mental states, the problem of functionally false beliefs, and problems about indeterminacy or multiplicity of function
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