1,192 research outputs found
The Tidal Prism, Viable Eelgrass Habitat, And The Effects Of Sea Level Rise In Morro Bay
The tidal prism, or the volume of water exchanged from the sea to an estuary from mean low to mean high tide, influences system hydrodynamics and ecological functioning. Since 1884, the tidal prism in Morro Bay, California has been estimated to be decreasing over time due to sedimentation from upstream practices. What is the current tidal prism in Morro Bay and how will that change with sea level rise? How will eelgrass respond to rising sea levels?
For this study, inexpensive tidal gauges were deployed at four locations in Morro Bay from March to August 2023 to measure spatially varying tidal elevations and datums within the bay. I utilized a Digital Elevation Model (DEM) and tidal information to determine volumes of water in Morro Bay. Estimated sea level rise scenarios were utilized to project the 2022 tidal prism into the years 2050 and 2100. Additionally, I estimated the 2019 and 2022 viable eelgrass habitat area using the vertical growth range. I estimated the future potential viable habitat area in the years 2050 and 2100 using estimated sea level rise scenarios. Future projections were made assuming no change in bathymetry over time.
Different instruments used to obtain water levels yielded up to ~4 percent differences in the tidal prism estimate. Measurement uncertainty in the monthly tidal datums produced ~3 percent uncertainty within the tidal prism estimate. Compared to the tidal prism in August 2019, the August 2022 tidal prism was lower by ~2 percent. Compared to the tidal prism in August 2019, the August 2023 tidal prism estimated from two nearly co-located tidal instruments at the mouth of Morro Bay were higher by ~5 and ~7 percent, respectively. Spatially varying tidal datums in Morro Bay were found to affect the tidal prism by up to ~3 percent, compared to tidal prism estimates using only a tidal datum near the estuary mouth. However, the effect of spatially varying tidal datums on the tidal prism is the same order of magnitude as measurement uncertainty and is thus not statistically significant. As sea levels rise, the tidal prism is projected to increase by ~40 percent by 2100 from 2022 under the most extreme scenario, H++. Initially, as sea levels rise, the potential viable eelgrass habitat area will increase from the area in 2022 (1108 acres (4.47E+06 m2)). After sea levels rise to 1.5 m above 2000 levels, the potential viable eelgrass area will have reached a maximum area of 1938 acres (7.82E+06 m2). However, under SLR scenario H++, potential viable habitat area is predicted to decrease by up to 59% by 2100 from 2022.
The tidal prism, or the volume of water exchanged from a bay to the seathe sea to an estuary from mean lowhigh to mean highlow tide, influences system hydrodynamics and ecological functioning. Since 1884, the tidal prism in Morro Bay, California has been estimated to be decreasing over time due to sedimentation from upstream practices. What is the current tidal prism in Morro Bay and how will that change with sea level rise? How will eelgrass respond to rising sea levels?
For this study, inexpensive tidal gauges were deployed at four locations in Morro Bay from March to August 2023 to obtain measure spatially varying tidal elevations and datums within the bay. I utilized a Digital Elevation Model (DEM) and tidal information from NOAA to determine volumes of water in Morro Bay at the estimated monthly mean tidal datums. Estimated sea level rise scenarios were utilized to project the 2022 tidal prism into the years 2050 and 2100. Additionally, I estimated the 2019 and 2022 viable eelgrass habitat area using the vertical growth range. I estimated the future potential viable habitat area in the years 2050 and 2100 using estimated sea level rise scenariosfor various sea level rise scenarios.Future projections were made assuming no change in bathymetry over time.
Different instruments used to obtainwater levels yielded up to ~4 percent differences in the tidal prism estimate. Measurement uncertainty in the monthly tidal datums produced~3 percent uncertainty within the tidal prism estimate. Compared to the tidal prism in August 2019, the August 2022 tidal prism from Stilltek decreasedwas lower by ~2.05 percent. Compared to the tidal prism in August 2019, the August 2023 tidal prism estimated from the Stilltek gauge and the Cal Poly Coast Guard gaugetwo nearly co-located tidal instruments at the mouth of Morro Bay increased were higher by ~5.06 and ~6.777 percent, respectively. Spatially varying tidal datums in Morro Bay were found to affect the tidal prism by up to ~2.883 percent, compared to tidal prism estimates using only a tidal datum near the estuary mouth. However, the effect of spatially varying tidal datums on the tidal prism is the same order of magnitude as measurement uncertainty and is thus not statistically significant. As sea levels rise, the tidal prism is projected to increase by ~to a maximum of 40 percent by 2100 from 2022 under the most extreme scenario, H++. InitiallyInitially, as sea levels rise, the potential viable eelgrass habitat area will increase from the area in 2022 (1108 acres (4.47E+06 m2)). ABut after sea levels rise to 1.5 m above 2000 levels, the potential viable eelgrass areas will have reached the thresholda maximum area of 1938 acres (7.82E+06 m2). However, under SLR scenario H++, potential viable habitat area is predicted to decrease by up to 59% by 2100 from 2022
Proceedings of the 1995 Annual Symposium on Engineering Geology and Geotechnical Engineering (No. 31)
Locus of Control and Job Search Strategies
Standard job search theory assumes that unemployed individuals have perfect information about the effect of their search effort on the job offer arrival rate. In this paper, we present an alternative model which assumes instead that each individual has a subjective belief about the impact of his or her search effort on the rate at which job offers arrive. These beliefs depend in part on an individual's locus of control, i.e., the extent to which a person believes that future outcomes are determined by his or her own actions as opposed to external factors. We estimate the impact of locus of control on job search behavior using a novel panel data set of newly-unemployed individuals in Germany. Consistent with our theoretical predictions, we find evidence that individuals with an internal locus of control search more and that individuals who believe that their future outcomes are determined by external factors have lower reservation wages.job search behavior, search effort, reservation wage, locus of control, unemployment duration
Molybdenum sputtering film characterization for high gradient accelerating structures
Technological advancements are strongly required to fulfill the demands of
new accelerator devices with the highest accelerating gradients and operation
reliability for the future colliders. To this purpose an extensive R&D
regarding molybdenum coatings on copper is in progress. In this contribution we
describe chemical composition, deposition quality and resistivity properties of
different molybdenum coatings obtained via sputtering. The deposited films are
thick metallic disorder layers with different resistivity values above and
below the molibdenum dioxide reference value. Chemical and electrical
properties of these sputtered coatings have been characterized by Rutherford
backscattering, XANES and photoemission spectroscopy. We will also present a
three cells standing wave section coated by a molybdenum layer 500 nm
thick designed to improve the performance of X-Band accelerating systems.Comment: manuscript has been submitted and accepted by Chinese Physics C
(2012
Real-time PCR improves detection of Trichomonas vaginalis infection compared with culture using self-collected vaginal swabs.
OBJECTIVE: To compare a real-time polymerase chain reaction (PCR) assay with broth culture for the detection of Trichomonas vaginalis using self-collected vaginal swabs. METHODS: Self-collected vaginal swabs were obtained from adolescent and young adult African-American women participating in HIV-1 prevention programs. T. vaginalis culture was performed using the InPouch TV System. Samples for the real-time PCR assay were collected using the BDProbeTec ET Culturette Direct Dry Swab system and tested in a laboratory-developed assay which targeted a repeated sequence of the genome. Discrepant samples that were culture negative and positive in the real-time PCR assay were tested in a confirmatory PCR which targeted a different region of the T. vaginalis genome, the18S ribosomal DNA gene. RESULTS: Of the 524 specimens tested by both culture and real-time PCR, 36 were culture positive and 54 were positive in the real-time PCR assay; 16 of the 18 discrepant specimens were also positive in the confirmatory PCR assay. Using a modified gold standard of positive by culture or positive in both PCR assays, the sensitivity of the real-time PCR assay was 100% and the specificity was 99.6%, whereas culture had a sensitivity of 69.2% and a specificity of 100%. CONCLUSIONS: The real-time PCR assay was sensitive and specific for the detection of T. vaginalis DNA from self-collected vaginal swab specimens. The ability to use the BDProbeTec dry swab system for the real-time PCR testing allowed for the detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and T. vaginalis from a single specimen
Trends in h2s-donors chemistry and their effects in cardiovascular diseases
Hydrogen sulfide (H2S) is an endogenous gasotransmitter recently emerged as an important regulatory mediator of numerous human cell functions in health and in disease. In fact, much evidence has suggested that hydrogen sulfide plays a significant role in many physio-pathological processes, such as inflammation, oxidation, neurophysiology, ion channels regulation, cardiovascular protection, endocrine regulation, and tumor progression. Considering the plethora of physiological effects of this gasotransmitter, the protective role of H2S donors in different disease models has been extensively studied. Based on the growing interest in H2S-releasing compounds and their importance as tools for biological and pharmacological studies, this review is an exploration of currently available H2S donors, classifying them by the H2S-releasing-triggered mechanism and highlighting those potentially useful as promising drugs in the treatment of cardiovascular diseases
UV Sensor Based on Surface Acoustic Waves in ZnO/Fused Silica
Zinc oxide (ZnO) thin films have been grown by radio frequency sputtering technique on fused silica substrates. Optical and morphological characteristics of as-grown ZnO samples were measured by various techniques; an X-ray diffraction spectrum showed that the films exhibited hexagonal wurtzite structure and were c-axis-oriented normal to the substrate surface. Scanning electron microscopy images showed the dense columnar structure of the ZnO layers, and light absorption measurements allowed us to estimate the penetration depth of the optical radiation in the 200 to 480 nm wavelength range and the ZnO band-gap. ZnO layers were used as a basic material for surface acoustic wave (SAW) delay lines consisting of two Al interdigitated transducers (IDTs) photolithographically implemented on the surface of the piezoelectric layer. The Rayleigh wave propagation characteristics were tested in darkness and under incident UV light illumination from the top surface of the ZnO layer and from the fused silica/ZnO interface. The sensor response, i.e., the wave velocity shift due to the acoustoelectric interaction between the photogenerated charge carriers and the electric potential associated with the acoustic wave, was measured for different UV power densities. The reversibility and repeatability of the sensor responses were assessed. The time response of the UV sensor showed a rise time and a recovery time of about 10 and 13 s, respectively, and a sensitivity of about 318 and 341 ppm/(mW/cm2) for top and bottom illumination, respectively. The ZnO/fused silica-based SAW UV sensors can be interrogated across the fused silica substrate thanks to its optical transparency in the UV range. The backlighting interrogation can find applications in harsh environments, as it prevents the sensing photoconductive layer from aggressive environmental effects or from any damage caused by cleaning the surface from dust which could deteriorate the sensor’s performance. Moreover, since the SAW sensors, by their operating principle, are suitable for wireless reading via radio signals, the ZnO/fused-silica-based sensors have the potential to be the first choice for UV sensing in harsh environments
Effect of HSV-2 Suppressive Therapy on Genital Tract HIV-1 RNA Shedding among Women on HAART: A Pilot Randomized Controlled Trial
Background. The role of suppressive HSV therapy in women coinfected with HSV-2 and HIV-1 taking highly active antiretroviral therapy (HAART) is unclear. Methods. 60 women with HIV-1/HSV-2 coinfection on HAART with plasma HIV-1 viral load (PVL) ≤75 copies/mL were randomized to receive acyclovir (N = 30) or no acyclovir (N = 30). PVL, genital tract (GT) HIV-1, and GT HSV were measured every 4 weeks for one year. Results. Detection of GT HIV-1 was not significantly different in the two arms (OR 1.23, P = 0.67), although this pilot study was underpowered to detect this difference. When PVL was undetectable, the odds of detecting GT HIV were 0.4 times smaller in the acyclovir arm than in the control arm, though this was not statistically significant (P = 0.07). The odds of detecting GT HSV DNA in women receiving acyclovir were significantly lower than in women in the control group, OR 0.38, P < 0.05. Conclusions. Chronic suppressive therapy with acyclovir in HIV-1/HSV-2-positive women on HAART significantly reduces asymptomatic GT HSV shedding, though not GT HIV shedding or PVL. PVL was strongly associated with GT HIV shedding, reinforcing the importance of HAART in decreasing HIV sexual transmission
Is Entrepreneurial Success Predictable? An Ex-Ante Analysis of the Character-Based Approach
This paper empirically analyzes whether the character-based approach, which focuses on the personality structure and the human capital of business founders, allows prediction of entrepreneurial success. A unique data set is used consisting of 414 persons whose personal characteristics were analyzed by different methods, namely an one-day assessment center (AC) and a standardized questionnaire, before they launched their business. Results are partly unexpected and weaker than previous ex-post findings: first, we found correlations between the AC data and the questionnaire in one subgroup only. Second, the predictive power of the AC data is slightly better than that of the questionnaire, but lower than expected in theory. Interestingly, for those subgroups where the AC data have low predictive power, the questionnaire does better. Third, when success is measured in terms of employees hired, the character-based approach is a poor predictor. Copyright 2008 The Authors.
- …