11,619 research outputs found
Chronic Career Indecision: Amalgamate Career Development Theories and Action Research Perspectives
"This article seeks to explore chronic career indecision in light of career
development theories and action research perspectives, aiming to delineate
some intervention strategies. Firstly, the issue of career indecision in
general is examined, and research in this area is then utilised to fuel a
discussion of chronic career indecision in particular. Attention is drawn to
the antecedents of chronic career indecision, including personality factors
and social and situational factors, and the psychological, interpersonal,
and general well-being of chronically undecided individuals is then examined.
Secondly, concepts are reviewed from three career development
theories, namely the life-span life-space theory, the cognitive information
processing theory, and the narrative approach, as they relate to chronic career
indecision. Finally, along with an action research perspective, several
intervention strategies are proposed which career counsellors may find
helpful when working with chronically undecided individuals." (author's abstract
Ultrasonic imaging front-end design for CMUT: A 3-level 30Vpp pulse-shaping pulser with improved efficiency and a noise-optimized receiver
A four-channel analog front-end (AFE) transceiver chip for medical ultrasound imaging is demonstrated. The high voltage transmitter uses a 3-level pulse-shaping technique to deliver over 50% more acoustic power for the same power dissipation, compared to traditional methods. The design requires minimum off-chip components and is scalable for more channels. The receiver is implemented with a transimpedance amplifier (TIA) topology and is optimized for noise, bandwidth and power dissipation. Based on both acoustic and electrical measurements, we demonstrate the Transmitter (Tx) efficiency improvement, Tx beamformation and the pulse-echo response, revealing the system's full functionality.Semiconductor Research Corporation. Focus Center for Circuit and System Solutions (C2S2
Transport in Molecular Junctions with Different Metallic Contacts
Ab initio calculations of phenyl dithiol connected to Au, Ag, Pd, and Pt
electrodes are performed using non-equilibrium Green's functions and density
functional theory. For each metal, the properties of the molecular junction are
considered both in equilibrium and under bias. In particular, we consider in
detail charge transfer, changes in the electrostatic potential, and their
subsequent effects on the IV curves through the junctions. Gold is typically
used in molecular junctions because it forms strong chemical bonds with sulfur.
We find however that Pt and Pd make better electrical contacts than Au. The
zero-bias conductance is found to be greatest for Pt, followed by Pd, Au, and
then Ag
Ultrasonic Imaging Transceiver Design for CMUT: A Three-Level 30-Vpp Pulse-Shaping Pulser With Improved Efficiency and a Noise-Optimized Receiver
This paper demonstrates a four-channel transceiver chip for medical ultrasonic imaging, interfacing to the capacitive micromachined ultrasonic transducers (CMUTs). The high-voltage transmitter (Tx) uses a three-level pulse-shaping technique with charge recycling to improve the power efficiency. The design requires minimum off-chip components and is scalable for more channels. The receiver is implemented with a transimpedance amplifier (TIA) topology and is optimized for tradeoffs between noise, bandwidth, and power dissipation. The test chip is characterized with both acoustic and electrical measurements. Comparing the three-level pulser against traditional two-level pulsers, the measured Tx efficiency shows 56%, 50%, and 43% more acoustic power delivery with the same total power dissipation at 2.5, 3.3, and 5.0 MHz, respectively. The CMUT receiver achieves the lowest noise efficiency factor compared with that of the literature (2.1 compared to a previously reported lowest of 3.6, in units of mPA ·√(mW/Hz). In addition, the transceiver chip is tested as a complete system for medical ultrasound imaging applications, in experiments including Tx beamformation, pulse-echo channel response characterization, and ultrasonic Doppler flow rate detection.Semiconductor Research Corporation. Focus Center for Circuit and System Solutions (C2S2
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Different Slopes for Different Folks: Socioeconomic and Racial/Ethnic Disparities in Asthma and Hay Fever among 173,859 U.S. Men and Women.
Although allergic diseases such as asthma and hay fever are a major cause of morbidity in industrialized countries, most studies have focused on patterns of prevalence among children and adolescents, with relatively few studies on variations in prevalence by race/ethnicity and socioeconomic position among adults. Our study examined racial/ethnic and socioeconomic patterns in the prevalence of asthma overall, asthma with hay fever, asthma without hay fever, and hay fever overall, in a population of 173,859 women and men in a large prepaid health plan in northern California. Using education as a measure of socioeconomic position, we found evidence of a positive gradient for asthma with hay fever with increasing level of education but an inverse gradient for asthma without hay fever. Hay fever was also strongly associated with education. Compared with their White counterparts, Black women and men were more likely to report asthma without hay fever, and Black women were less likely to have asthma with hay fever. Asian men were also more likely to report asthma with hay fever, and Asian women and men were much more likely to have hay fever. Racial/ethnic disparities in prevalence of allergic diseases were largely independent of education. We discuss implications for understanding these social inequalities in allergic disease risk in relation to possible differences in exposure to allergens and determinants of immunologic susceptibility and suggest directions for future research
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Oral Cytokine Levels Are More Linked to Levels of Plasma and Oral HIV-1 RNA Than to CD4+ T-Cell Counts in People With HIV.
BackgroundWe determined the levels of 11 soluble immune mediators in oral washings of AIDS Clinical Trials Group A5254 participants with varying degrees of plasma viremia and CD4 T-cell counts to characterize the mucosal immune response at different stages of HIV-1 infection.MethodsA5254 was a multicenter, cross-sectional study in people with HIV (PWH) recruited into 4 strata based on CD4 count and levels of plasma viremia: stratum (St) A: CD4 ≤200 cells/mm3, HIV-1 RNA (viral load [VL]) >1000 cps/mL; St B: CD4 ≤200, VL ≤1000; St C: CD4 >200, VL >1000; St D: CD4 >200, VL ≤1000. Oral/throat washings were obtained from all participants. Soluble markers were tested in oral/throat washings using a multibead fluorescent platform and were compared across strata. Linear regression was used to determine the associations between cytokines and HIV-1 in plasma and oral fluid.ResultsSt A participants had higher levels of interleukin (IL)-1β, IL-6, IL-17, tumor necrosis factor alpha (TNFα), and interferon gamma (IFNγ) compared with St B and D (P = .02; P < .0001) but were not different from St C. IL-8, IL-10, and IL-12 were elevated in St A compared with the other 3 strata (P = .046; P < .0001). Linear regression demonstrated that oral HIV-1 levels were associated with IL-1β, IL-6, IL-8, and TNFα production (R > .40; P < .001) when controlling for CD4 count and opportunistic infections.ConclusionsOur results show that high levels of oral HIV-1, rather than low CD4 counts, were linked to the production of oral immune mediators. Participants with AIDS and uncontrolled viremia demonstrated higher levels of pro- and anti-inflammatory soluble immune mediators compared with participants with lower HIV-1 RNA. The interplay of HIV-1 and these immune mediators could be important in the oral health of PWH
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Investigation of discrepancies in satellite rainfall estimates over Ethiopia
Tropical Applications of Meteorology Using Satellite and Ground-Based Observations (TAMSAT) rainfall estimates are used extensively across Africa for operational rainfall monitoring and food security applications; thus, regional evaluations of TAMSAT are essential to ensure its reliability. This study assesses the performance of TAMSAT rainfall estimates, along with the African Rainfall Climatology (ARC), version 2; the Tropical Rainfall Measuring Mission (TRMM) 3B42 product; and the Climate Prediction Center morphing technique (CMORPH), against a dense rain gauge network over a mountainous region of Ethiopia. Overall, TAMSAT exhibits good skill in detecting rainy events but underestimates rainfall amount, while ARC underestimates both rainfall amount and rainy event frequency. Meanwhile, TRMM consistently performs best in detecting rainy events and capturing the mean rainfall and seasonal variability, while CMORPH tends to overdetect rainy events. Moreover, the mean difference in daily rainfall between the products and rain gauges shows increasing underestimation with increasing elevation. However, the distribution in satellite–gauge differences demon- strates that although 75% of retrievals underestimate rainfall, up to 25% overestimate rainfall over all eleva- tions. Case studies using high-resolution simulations suggest underestimation in the satellite algorithms is likely due to shallow convection with warm cloud-top temperatures in addition to beam-filling effects in microwave- based retrievals from localized convective cells. The overestimation by IR-based algorithms is attributed to nonraining cirrus with cold cloud-top temperatures. These results stress the importance of understanding re- gional precipitation systems causing uncertainties in satellite rainfall estimates with a view toward using this knowledge to improve rainfall algorithms
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