442 research outputs found
ADA activity in the follicular fluid of infertile women with diminished ovarian reserve can act as a predictor of ovarian reserve
Background: Adenosine deaminase (ADA) catalyses the deamination of adenosine to inosine. In the human reproductive tract, the importance of enzymes that affect metabolism of adenosine, particularly ADA, has been emphasized. It is aimed to evaluate the plasma and follicular fluid (FF) activities of total ADA (ADAT) in infertile women and to determine its relation with ovarian reserve markers and in vitro fertilization (IVF) outcomes.Methods: Plasma and FF activities of ADAT were measured in 106 infertile women. Its relation with ovarian reserve markers and IVF outcomes were determined.Results: There was a significant difference in the ADAT activities between plasma and FF of infertile women (p<0.01). The activity of plasma ADAT was higher than FF ADAT in infertile women (p<0.01). The activity of FF ADAT in DOR group was higher than that of the others (p<0.01). In DOR group; the activity of FF ADAT activity had a negative correlation with BMI and a positive correlation with FSH and no relation with IVF outcomes.Conclusions: Increased ADAT activity can lead to reduced adenosine levels, which might be resulted in disturbed fertility process. The activity of FF ADAT activity might be important for fertility work-up. Further studies are needed
Absolute properties of the binary system BB Pegasi
We present a ground based photometry of the low-temperature contact binary BB
Peg. We collected all times of mid-eclipses available in literature and
combined them with those obtained in this study. Analyses of the data indicate
a period increase of 3.0(1) x 10^{-8} days/yr. This period increase of BB Peg
can be interpreted in terms of the mass transfer 2.4 x 10^{-8} Ms yr^{-1} from
the less massive to the more massive component. The physical parameters have
been determined as Mc = 1.42 Ms, Mh = 0.53 Ms, Rc = 1.29 Rs, Rh = 0.83 Rs, Lc =
1.86 Ls, and Lh = 0.94 Ls through simultaneous solution of light and of the
radial velocity curves. The orbital parameters of the third body, that orbits
the contact system in an eccentric orbit, were obtained from the period
variation analysis. The system is compared to the similar binaries in the
Hertzsprung-Russell and Mass-Radius diagram.Comment: 17 pages, 3 figures, accepted for Astronomical Journa
Egypt’s 2011–2012 parliamentary elections: Voting for religious vs. secular democracy?
This study investigates whether individuals’ attitudes towards democracy and
secular politics have any influence on voting behavior in Egypt. Based on data
from a survey conducted immediately after the Egyptian parliamentary elections
in January 2012, this study finds that Egyptians’ attitudes towards democratic
governance were quite negative around the parliamentary elections, yet Egyptians
still endorsed democracy as the ideal political system for their country. However,
empirical findings suggest that support for democracy has a limited impact on
electoral results. On the other hand, the main division in Egyptian society around
the first free and fair parliamentary elections was the religious-secular cleavage. As
people support secular politics more, they become significantly less likely to vote
for Islamist parties. These results illustrate that preferences in regard to the type
of democracy – either a liberal and secular or a religious democracy – were
the main determinant of the historic 2012 elections in Egypt
Using Schema Training to Facilitate Students\u27 Understanding of Challenging Engineering Concepts in Heat Transfer and Thermodynamics
Background: Chi and colleagues have argued that some of the most challenging engineering concepts exhibit properties of emergent systems. However, students often lack a mental framework, or schema, for understanding emergence. Slotta and Chi posited that helping students develop a schema for emergent systems, referred to as schema training, would increase the understanding of challenging concepts exhibiting emergent properties.
Purpose: We tested the effectiveness of schema training and explored the nature of challenging concepts from thermodynamics and heat transfer. We investigated if schema training could (a) repair misconceptions in advanced engineering students and (b) prevent them in beginning engineering students.
Method: We adapted Slotta and Chi\u27s schema training modules and tested their impact in two studies that employed an experimental design. Items from the Thermal and Transport Concept Inventory and expert-developed multiple-choice questions were used to evaluate conceptual understanding of the participants. The language used by students in their open-ended explanations of multiple-choice questions was also coded.
Results: In both studies, students in the experimental groups showed larger gains in their understanding of some concepts—specifically in dye diffusion and microfluidics in Study One, and in the final test for thermodynamics in Study Two. But in neither study did students exhibit any gain in conceptual questions about heat transfer.
Conclusion: Our studies suggest the importance of examining the nature of the phenomena underlying the concepts being taught because the language used in instruction has implications for how students understand them. Therefore, we suggest that instructors reflect on their own understanding of the concepts
Effect of cartilage thickness mismatch in osteochondral grafting from knee to talus on articular contact pressures: A finite element analysis
Objectives: The aim of this study was to investigate the effect of cartilage thickness mismatch on tibiotalar articular contact pressure in osteochondral grafting from femoral condyles to medial talar dome using a finite element analysis (FEA). Materials and methods: Flush-implanted osteochondral grafting was performed on the talar centromedial aspect of the dome using osteochondral plugs with two different cartilage thicknesses. One of the plugs had an equal cartilage thickness with the recipient talar cartilage and the second plug had a thicker cartilage representing a plug harvested from the knee. The ankle joint was loaded during a single-leg stance phase of gait. Tibiotalar contact pressure, frictional stress, equivalent stress (von Mises values), and deformation were analyzed. Results: In both osteochondral grafting simulations, tibiotalar contact pressure, frictional stress, equivalent stress (von Mises values) on both tibial and talar cartilage surfaces were restored to near-normal values. Conclusion: Cartilage thickness mismatch does not significantly change the tibiotalar contact biomechanics, when the graft is inserted flush with the talar cartilage surface
Rose oil inhalation protects against formaldehyde-induced testicular damage in rats
In this experimental study, harmful effects of formaldehyde (FA) inhalation on
sperm concentration, sperm quality, serum testosterone levels and the rat testes
were investigated. In addition, the possible protective effects of rose oil against
to these harmful effects were evaluated. For this purpose, 21 albino-Wistar rats
were used. The rats in Group I were used as control group. When the rats of
Group II were exposed FA (10 ppm/1 h) for 35 days, the rats of Group III
inhalated rose oil (1 ml/1 h) after FA. The epididymal tissues were taken for
sperm analysing and the testes were removed for histological examination. In
addition, testosterone levels were determined from the blood samples.
Although the testosterone levels, the epididymal sperm concentration, and the
progressive sperm motility significantly decreased, the abnormal sperm rate
significantly increased in the Group II when compared to Group I. In the
Group III, these damages were seen less. When the rats in the Group II
compared with the control group, there were serious histological damages. In
the Group III, it was determined that the histological changes were less than
group II. It can be expressed that serious damages occurred via formaldehyde
exposure in male reproductive system and that the rose oil had protective
effects against these damages
Image Classification for Age-related Macular Degeneration Screening Using Hierarchical Image Decompositions and Graph Mining
Age-related Macular Degeneration (AMD) is the most common cause of adult blindness in the developed world. This paper describes a new image mining technique to perform automated detection of AMD from color fundus photographs. The technique comprises a novel hierarchical image decomposition mechanism founded on a circular and angular partitioning. The resulting decomposition is then stored in a tree structure to which a weighted frequent sub-tree mining algorithm is applied. The identified sub-graphs are then incorporated into a feature vector representation (one vector per image) to which classification techniques can be applied. The results show that the proposed approach performs both efficiently and accurately
Charged-Particle Multiplicities in Charged-Current Neutrino-- and Anti-Neutrino--Nucleus Interactions
The CHORUS experiment, designed to search for
oscillations, consists of a nuclear emulsion target and electronic detectors.
In this paper, results on the production of charged particles in a small sample
of charged-current neutrino-- and anti-neutrino--nucleus interactions at high
energy are presented. For each event, the emission angle and the ionization
features of the charged particles produced in the interaction are recorded,
while the standard kinematic variables are reconstructed using the electronic
detectors. The average multiplicities for charged tracks, the pseudo-rapidity
distributions, the dispersion in the multiplicity of charged particles and the
KNO scaling are studied in different kinematical regions. A study of
quasi-elastic topologies performed for the first time in nuclear emulsions is
also reported. The results are presented in a form suitable for use in the
validation of Monte Carlo generators of neutrino--nucleus interactions.Comment: 17 pages, 5 figure
Leading order analysis of neutrino induced dimuon events in the CHORUS experiment
We present a leading order QCD analysis of a sample of neutrino induced
charged-current events with two muons in the final state originating in the
lead-scintillating fibre calorimeter of the CHORUS detector. The results are
based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign
dimuon events collected during the exposure of the detector to the CERN Wide
Band Neutrino Beam between 1995 and 1998. % with GeV
and GeV collected %between 1995 and 1998. The analysis yields a
value of the charm quark mass of \mc = (1.26\pm 0.16 \pm 0.09) \GeVcc and a
value of the ratio of the strange to non-strange sea in the nucleon of , improving the results obtained in similar analyses
by previous experiments.Comment: Submitted to Nuclear Physics
Associated Charm Production in Neutrino-Nucleus Interactions
In this paper a search for associated charm production both in neutral and
charged current -nucleus interactions is presented. The improvement of
automatic scanning systems in the {CHORUS} experiment allows an efficient
search to be performed in emulsion for short-lived particles. Hence a search
for rare processes, like the associated charm production, becomes possible
through the observation of the double charm-decay topology with a very low
background. About 130,000 interactions located in the emulsion target
have been analysed. Three events with two charm decays have been observed in
the neutral-current sample with an estimated background of 0.180.05. The
relative rate of the associated charm cross-section in deep inelastic
interactions, has been
measured. One event with two charm decays has been observed in charged-current
interactions with an estimated background of 0.180.06 and the
upper limit on associated charm production in charged-current interactions at
90% C.L. has been found to be .Comment: 10 pages, 4 figure
- …