279 research outputs found
An accurate Rb density measurement method for a plasma wakefield accelerator experiment using a novel Rb reservoir
A method to accurately measure the density of Rb vapor is described. We plan
on using this method for the Advanced Wakefield (AWAKE)~\cite{bib:awake}
project at CERN , which will be the world's first proton driven plasma
wakefield experiment. The method is similar to the hook~\cite{bib:Hook} method
and has been described in great detail in the work by W. Tendell Hill et.
al.~\cite{bib:densitymeter}. In this method a cosine fit is applied to the
interferogram to obtain a relative accuracy on the order of for the vapor
density-length product. A single-mode, fiber-based, Mach-Zenhder interferometer
will be built and used near the ends of the 10 meter-long AWAKE plasma source
to be able to make accurate relative density measurement between these two
locations. This can then be used to infer the vapor density gradient along the
AWAKE plasma source and also change it to the value desired for the plasma
wakefield experiment. Here we describe the plan in detail and show preliminary
results obtained using a prototype 8 cm long novel Rb vapor cell.Comment: 5 pages 9 figure
A research on asymptomatic bacteriuria in 14- to 17-year-old female students
Urinary tract infections, which are more common in women than in men, are especially seen in young asymptomatic females who don't obey the general rules of hygiene. This research has been carried out on 14- to 17-year-old young females from several high schools, 966 specimens in total. 3.3% of them had bacteriuria and 75% of the isolated bacteria was Escherichia coli. Copyright © 2004 S. Karger AG, Basel
Uptake, accumulation and some biochemical responses in Raphanus sativus L. to zinc stress
The responses of radish (Raphanus sativus L.) to increasing concentrations of ZnCl2 (1, 5 and 10 mM) in Hoagland nutrient medium were studied. Under the conditions of these increasing zinc concentrations, the highest zinc accumulation was obtained in the roots of the plants treated with 10 mM applications. The zinc concentration in the vegetative parts, was highest in the root and was lowest in the cotyledons. The highest bioconcentration factor (BCF) value was detected in the roots in 5 mM zinc applications. When compared with the control, total zinc uptake was observed to increase in 1, 5 and 10 mM ZnCl2 treatments. The total accumulation rate (TAR) for zinc was highest in 10 mM ZnCl2 treatment, while the lowest TAR was observed in radish plants exposed to 1 mM ZnCl2. Plants treated with 5, 10 mM ZnCl2 showed significant decreases in chlorophyll (Chl a, Chl b, Chl a/b) and carotenoid content compared with the control. Peroxidase (POD) activity especially in radish roots increased significantly with increasing concentrations of ZnCl2 (5 and 10 mM) while the total protein amount decreased when compared with the control. The results of this study showed that, radish plants could tolerate the negative effects of zinc stress up to 1 mM ZnCl2 concentration and that in zinc concentrations of 5 mM and above toxic effects were existent.Key words: Radish, Raphanus sativus, zinc, metal toxicity, uptake, accumulation, peroxidase, pigment
Exploring the relationship between traffic resilience and driver behaviors through traffic climate
Traffic safety culture and climate have emerged as an integral part of road safety policy and practice in recent decades, resulting in an emphasis on a holistic approach to road safety through systems thinking. The aim of this study was to investigate the relationship between drivers' perceptions of traffic resilience and traffic climate and their impact on driver behaviors. A total of 216 drivers aged between 19 and 32 years completed an online questionnaire consisting of the Traffic Resilience Scale (TRS), the Traffic Climate Scale (TCS), the Driver Behavior Questionnaire (DBQ), and the Positive Driver Behaviors Scale (PDBS). Serial mediation analyses were conducted to examine the objectives of the study. The results showed that drivers who perceived the traffic system as more resilient tended to perceive the traffic system as more functional and less externally demanding. The drivers' perceptions of traffic resilience were found to be directly related to the traffic climate and indirectly related to the driver behaviors through external affective demands and internal requirements. Increased traffic resilience was associated with increased aberrant behaviors and decreased positive behaviors through reduced external affective demands and internal requirements. These findings can be considered to make a unique contribution to the literature in understanding the motivations behind aberrant behaviors of drivers and highlight the need for road safety policies to take into account road users' perceptions of traffic resilience and traffic climate in order to better understand, predict, and modify road user behaviors for a safer traffic system
Time-Kill Kinetics and In Vitro Antifungal Susceptibility of Non-fumigatus Aspergillus Species Isolated from Patients with Ocular Mycoses
Aspergillus species can cause ocular morbidity and blindness, and thus, appropriate antifungal therapy is needed. We investigated the in vitro activity of itraconazole, voriconazole, posaconazole, caspofungin, anidulafungin, and amphotericin B against 14 Aspergillus isolates obtained from patients with ocular mycoses, using the CLSI reference broth microdilution methodology. In addition, time-kill assays were performed, exposing each isolate separately to 1-, 4-, and 16-fold concentrations above the minimum inhibitory concentration (MIC) of each antifungal agent. A sigmoid maximum-effect (Emax) model was used to fit the time-kill curve data. The drug effect was further evaluated by measuring an increase/decrease in the killing rate of the tested isolates. The MICs of amphotericin B, itraconazole, voriconazole, and posaconazole were 0.5–1.0, 1.0, 0.5–1.0, and 0.25 µg/ml for A. brasiliensis, A. niger, and A. tubingensis isolates, respectively, and 2.0–4.0, 0.5, 1.0 for A. flavus, and 0.12–0.25 µg/ml for A. nomius isolates, respectively. A. calidoustus had the highest MIC range for the azoles (4.0–16.0 µg/ml) among all isolates tested. The minimum effective concentrations of caspofungin and anidulafungin were ≤0.03–0.5 µg/ml and ≤0.03 µg/ml for all isolates, respectively. Posaconazole demonstrated maximal killing rates (Emax = 0.63 h−1, r2 = 0.71) against 14 ocular Aspergillus isolates, followed by amphotericin B (Emax = 0.39 h−1, r2 = 0.87), voriconazole (Emax = 0.35 h−1, r2 = 0.098), and itraconazole (Emax = 0.01 h−1, r2 = 0.98). Overall, the antifungal susceptibility of the non-fumigatusAspergillus isolates tested was species and antifungal agent dependent. Analysis of the kinetic growth assays, along with consideration of the killing rates, revealed that posaconazole was the most effective antifungal against all of the isolates
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The interplay between learner beliefs and foreign language anxiety: insights from the Turkish EFL context
Foreign language learning in classroom settings has long been found to be associated with anxiety (Horwitz, 1986). Though it is known that sources of foreign language anxiety are varied (Young, 1991), whether anxiety is related to learners’ inherent beliefs about language learning is understudied. To this end, the present study examines the possible relationship between learner beliefs and language anxiety in the under-researched Turkish EFL context. A population of university-level Turkish EFL learners (n=153) completed the Beliefs about Language Learning Inventory (BALLI) and the Foreign Language Classroom Anxiety scale (FLCAS). The underlying constructs in both instruments were explored using an Exploratory Factor Analysis (EFA). A series of Pearson Product-Moment Correlation Coefficient (PPMCC) tests were performed on the factor scores from both instruments. The findings revealed that fear of ambiguity was positively linked to classroom performance anxiety and negative feelings towards English. In addition, the more confident learners feel themselves using English, the more desire they seem to have to interact with native speakers. Overall, positive beliefs about language learning may be helpful in reducing anxiety and boosting confidence in language learning. These findings not only enhance our understanding of the complex psychology of language learning but also have important implications for instructed EFL/ESL settings
Experimental determination of axion signal power of dish antennas and dielectric haloscopes using the reciprocity approach
The reciprocity approach is a powerful method to determine the expected
signal power of axion haloscopes in a model-independent way. Especially for
open and broadband setups like the MADMAX dielectric haloscope the sensitivity
to the axion field is difficult to calibrate since they do not allow discrete
eigenmode analysis and are optically too large to fully simulate. The central
idea of the reciprocity approach is to measure a reflection-induced test field
in the setup instead of trying to simulate the axion-induced field. In this
article, the reciprocity approach is used to determine the expected signal
power of a dish antenna and a minimal dielectric haloscope directly from
measurements. The results match expectations from simulation but also include
important systematic effects that are too difficult to simulate. In particular,
the effect of antenna standing waves and higher order mode perturbations can be
quantified for the first time in a dielectric haloscope.Comment: v2, updated to match journal version, 18 pages, 10 figure
Ion source and LEBT of KAHVELab proton beamline
The KAHVE Laboratory, at Bo\u{g}azi\c{c}i University, Istanbul, Turkey is
home to an educational proton linac project. The proton beam will originate
from a 20 keV H+ source and will be delivered to a two module Radio Frequency
Quadrupole (RFQ) operating at 800 MHz via a low energy beam transport (LEBT)
line. Currently, the design phase being over, commissioning and stability tests
are ongoing for the proton beamline which is already produced and installed
except the RFQ which is being manufactured. This work summarizes the design,
production and test phases of the ion source and LEBT line components
Elevated Pontine and Putamenal GABA Levels in Mild-Moderate Parkinson Disease Detected by 7 Tesla Proton MRS
Background: Parkinson disease (PD) is characterized by the degeneration of nigrostriatal dopaminergic neurons. However, postmortem evidence indicates that the pathology of lower brainstem regions, such as the pons and medulla, precedes nigral involvement. Consistently, pontomedullary damage was implicated by structural and PET imaging in early PD. Neurochemical correlates of this early pathological involvement in PD are unknown. Methodology/Principal Finding: To map biochemical alterations in the brains of individuals with mild-moderate PD we quantified neurochemical profiles of the pons, putamen and substantia nigra by 7 tesla (T) proton magnetic resonance spectroscopy. Thirteen individuals with idiopathic PD (Hoehn & Yahr stage 2) and 12 age- and gender-matched healthy volunteers participated in the study. c-Aminobutyric acid (GABA) concentrations in the pons and putamen were significantly higher in patients (N = 11, off medications) than controls (N = 11, p,0.001 for pons and p,0.05 for putamen). The GABA elevation was more pronounced in the pons (64%) than in the putamen (32%). No other neurochemical differences were observed between patients and controls. Conclusion/Significance: The GABA elevation in the putamen is consistent with prior postmortem findings in patients with PD, as well as with in vivo observations in a rodent model of PD, while the GABA finding in the pons is novel. The more significant GABA elevation in the pons relative to the putamen is consistent with earlier pathological involvement of th
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