2,798 research outputs found
Field operations with cesium clocks in HF navigation systems
Networks of HF phase comparison marine navigation stations employing cesium clocks are discussed. The largest permanent network is in the Gulf of Mexico where some fourteen base stations are continuously active and others are activated as needed. These HF phase comparison systems, which operate on a single transmission path, require a clock on the mobile unit as well. Inventory consists of upwards of 70 clocks from two different manufacturers. The maintenance of this network as an operating system requires a coordinated effort involving clock preparation, clock environment control, station performance monitoring and field service
Resolving the Axial Mass Anomaly in neutrino Scattering
We present a parametrization of the observed enhancement in the transverse
electron quasielastic (QE) response function for nucleons bound in carbon as a
function of the square of the four momentum transfer (Q2) in terms of a
correction to the magnetic form factors of bound nucleons. The parametrization
should also be applicable to the transverse cross section in neutrino
scattering. If the transverse enhancement originates from meson exchange
currents (MEC), then it is theoretically expected that any enhancement in the
longitudinal or axial contributions is small. We present the predictions of the
"Transverse Enhancement" model (which is based on electron scattering data
only) for the neutrino and anti-neutrino differential and total QE cross
sections for nucleons bound in carbon. The 2Q2 dependence of the transverse
enhancement is observed to resolve much of the long standing discrepancy
("Axial Mass Anomaly}) in the QE total cross sections and differential
distributions between low energy and high energy neutrino experiments on
nuclear targets.Comment: 3 pages, 3 Figures, Presented by Arie Bodek at the 19th Particles and
Nuclei International Conference, PANIC 2011, MIT, Cambridge, MA July 201
Middle School Mathematics Students\u27 Perspectives on the Study of Mathematics
This qualitative study addressed the perceptions toward the study of mathematics by middle school students who had formerly been in a remedial mathematics program. The purpose of the study was to explore the past experiences of nine students in order to determine what is needed for them to feel successful in mathematics. The conceptual framework of the study was grounded in philosophies of motivation, including achievement goal theory, self-worth theory, self-efficacy theory, expectancy-value theory, and attribution theory. The study used a phenomenological research design to answer the key research question, which focused upon the experiences of students and the meaning that was given to these experiences. Data were collected and analyzed from individual interviews with 9 students and a focus group session. The findings of the study revealed that participants\u27 past experiences influenced their current attitudes about the study of mathematics. Perceptions of mathematical ability, history of success or failure with grades, and the influence of the teacher and peers in the learning environment most influenced students\u27 attitudes about mathematics. Moreover, current feelings impact the degree to which a student puts forth effort in the study of mathematics, and the relationship with the mathematics teacher had the greatest impact on student attitudes. To improve the perceptions that students have about the study of mathematics, expanded professional development opportunities may bring increased awareness of students\u27 perceptions of the study of mathematics, and develop remedial mathematics programs that remove the negative stigma associated with them. The research study could lead to social change as its purpose is to improve student achievement in mathematics through changes in the remedial mathematics program
Altitude dependence of atmospheric temperature trends: Climate models versus observation
As a consequence of greenhouse forcing, all state of the art general
circulation models predict a positive temperature trend that is greater for the
troposphere than the surface. This predicted positive trend increases in value
with altitude until it reaches a maximum ratio with respect to the surface of
as much as 1.5 to 2.0 at about 200 to 400 hPa. However, the temperature trends
from several independent observational data sets show decreasing as well as
mostly negative values. This disparity indicates that the three models examined
here fail to account for the effects of greenhouse forcings.Comment: 9 pages, 3 figure
EPITOPE PREDICTION AND STRUCTURAL ANALYSIS OF PRA ANTIGEN OF COCCIDIOIDES
Objective: Coccidioidomycosis is a life threatening human respiratory disease caused by Coccidioides immitis and C. posadasii. As the incidence of symptomatic Coccidioidomycosis increases worldwide, vaccine development strategy against Coccidioides is needed for both immunocompetent and immunocompromized individuals. An insight about PRA antigens in the pathogenesis of Coccidioidomycosis has the potential to develop a therapeutic intervention.
Methods: In this study of ANN, SMM and QM based servers were used to predict promiscuous epitopes. Epitope structures were modeled using De novo based PEPFOLD server and minimized using Swiss model server. Further the modeled epitopes were tested for their binding affinity towards HLA alleles by means of peptide protein docking studies involving autodock.
Results: A total of six antigenic epitopes ARISVSNIV, GRPTASTPA, ALNLFVEAL, LVAAGLASA, FSHALJALV, AEPTHEPTE of PRA showed hydrogen bonding with HLA alleles HLA-A*02:03, HLA B*27:05, HLA-A*02:01 with considerable bond distance. Thus, this systematic study on epitopes of Coccidioides study would be helpful in designing and developing novel PRA antigen based vaccine and inhibitor.
Conclusion: These predicted sequences are potential vaccine candidates but functional/biological assays should be performed to verify whether they are indeed appropriate to be included in a vaccine formulation
ANALYZING THE EFFECT OF NSSNPS IN CYP1A1 TOWARDS BENZOTHIAZOLES BINDING
Objective: CYP1A1 involved in biotransformation of carcinogenic polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines/amides (HAAs) and results in electrophilic reactive intermediates that leads to toxicity and cancer, thus influencing the fields of cancer research.Benzothiazole and its analogs are known for their anti-tumor activity because they act as potent aryl hydrocarbon receptor (AhR) agonist thus binds AhR and results in induction of CYP1A1 which forms DNA adduct and leads to cell death by activation of apoptotic mechanism. The main aim of this study is to extrapolate the relationship between nsSNPs of CYP1A1 and their effects in Benzothiazoles binding capability.Methods: Computational analysis of deleterious mutations in CYP1A1 and their impact on its structure were as well as altered drug response to Benzothiazoles based drug DF 203, NSC 674495 were studied. Furthermore molecular dynamics simulation (MDS) approach was conducted to investigate conformational changes in the mutant protein structure with respect to its native conformation.Results: Our studies revealed that 6 deleterious nsSNPs CYP1A1 have the impact on structural stability based on secondary structural patterns and molecular dynamics and altered drug response was seen in nsSNP rs2229150 (R93W) for the drug 2-(4-amino-3-methylphenyl) benzothiazole (DF 203, NSC 674495).Conclusion: Our study would be helpful to understand the nsSNP effect on CYP1A1 which in turn leads to carcinogenesis as well as Benzothiazole (DF-203) binding affinity and designing individualized therapeutic treatments
Minimum inhibitory concentration of squid ink Loligo sp. extract on growth of Staphylococcus aureus and Streptococcus mutans bacteria
Background: Dental caries and periodontal disease can be caused by bacteria that attack hard and soft tissues in the oral cavity like Staphylococcus aureus and Streptococcus mutans bacteria One way to prevent infections caused by the bacteria are by using mouthwash. Currently, mouthwash that is widely used is mouthwash containing chlorhexidine, which has side effects in the form of tooth staining when used prolonged. The need for alternative medicines from nature that effectively cope with polymicrobial infections. One of the marine products that has pharmaceutical properties is squid, especially the ink it produces.Methods: This research is a pure experimental study (true experimental design) with a randomized pretest-posttest control group design. Squid ink Loligo sp. extract, obtained by extracting squid ink Loligo sp., with maceration method using 96% ethanol solvent. This research uses serial dilution method with spectrophotometric testing method.Results: After measuring the turbidity value in each treatment tube, it was found that at a concentration of 1.56% squid ink Loligo sp. extract began to inhibit the growth of Staphylococcus aureus and Streptococcus mutans bacteria. This is proven because the absorbance value after and before incubation is fixed.Conclusions: The minimum inhibitory concentration of squid ink Loligo sp. extract on the growth of Staphylococcus aureus and Streptococcus mutants at a concentration of 1.56%
Climate dynamics experiments using a GCM simulations
The study of surface-atmosphere interactions has begun with studies of the effect of altering the ocean and land boundaries. A ten year simulation of global climate using observed sea surface temperature anomalies has begun using the NCAR Community Climate Model (CCM1). The results for low resolution (R15) were computed for the first 8 years of the simulation and compared with the observed surface temperatures and the MSU (Microwave Sounding Unit) observations of tropospheric temperature. A simulation at higher resolution (T42) was done to ascertain the effect of interactive soil hydrology on the system response to an El Nino sea surface temperature perturbation. Initial analysis of this simulations was completed
Protégé career aspirations: The influence of formal e-mentor networks and family-based role models
Using longitudinal data from a nine-month e-mentoring program, we analyzed the influence
of formal e-mentor networks and family-based role models on increases in both psychosocial
and career-related outcomes. Findings indicate that e-mentor network relationship quality
positively influenced general- and career-based self-efficacy which, in turn, enhanced the
objective career aspirations of underprivileged youth. Moreover, we address both the
compensatory and complementary perspectives of social capital to assess the moderating
influence that access to educational role models within the family has on this process.
Implications of the findings and areas for future research are discussed
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