The Ineludible non-Gaussianity of the Primordial Black Hole Abundance

We study the formation of primordial black holes when they are generated by the collapse of large overdensities in the early universe. Since the density contrast is related to the comoving curvature perturbation by a nonlinear relation, the overdensity statistics is unavoidably non-Gaussian. We show that the abundance of primordial black holes at formation may not be captured by a perturbative approach which retains the first few cumulants of the non-Gaussian probability distribution. We provide two techniques to calculate the non-Gaussian abundance of primordial black holes at formation, one based on peak theory and the other on threshold statistics. Our results show that the unavoidable non-Gaussian nature of the inhomogeneities in the energy density makes it harder to generate PBHs. We provide simple (semi-)analytical expressions to calculate the non-Gaussian abundances of the primordial black holes and show that for both narrow and broad power spectra the gaussian case from threshold statistics is reproduced by increasing the amplitude of the power spectrum by a factor ${\cal O}(2\div 3)$.Comment: 26 pages, 10 figures, matching published versio

Strong CP violation in spin-1/2 singly charmed baryons

We report on the calculation of the CP-violating form factor $F_3$ and the corresponding electric dipole moment for charmed baryons in the spin-1/2 sector generated by the QCD $\theta$-term. We work in the framework of covariant baryon chiral perturbation theory within the extended-on-mass-shell renormalization scheme up to next-to-leading order in the chiral expansion.Comment: 13 pages, 2 figures, extended introduction and discussion, version accepted for publication in JHE

Chiral constraints on the isoscalar electromagnetic spectral functions of the nucleon from leading order vector meson couplings

Using baryon chiral perturbation theory including vector mesons, we analyse various continuum contributions to the isoscalar electromagnetic spectral functions of the nucleon induced by the leading order couplings.Comment: 12 pages, 7 figure

Fen bilimleri öğretmenleri ve öğretmen adaylarına yönelik akıl yürütme becerileri testi’nin geliştirilmesi

The aim of this study is to develop a multiple choice test for determining inservice and preservice science teachers’ scientific reasoning skill levels which are frequently used in science lessons. This study is in survey model which is one of quantitative research methods. During test development process, existing multiple choice tests about scientific reasoning skills and sample questions were examined. Content validity of prepared pilot question form which consisted of 37 items at the beginning was provided via expert opinions. After completing the revisions, pilot form was implemented to 481 preservice science teachers studying at three different state universities and 48 in service science teachers working at various middle schools. After that, obtained data were subjected to item analysis and tetrachoric correlation based on exploratory factor analysis for construct validity respectively. Ten questions which have lower discrimination indexes than .30 were removed from the test at the end of item analysis. The final form of the test which is moderately difficult (p=0,523) and has high level of dicrimination (r jx =0,480) consisted of 27 items. KR-20 reliability coefficient of the test was found as .812. As a result of construct validity, it was determined that all items whose factor loadings change between .24 and .77 are under one factor. The findings of test development process showed that developed Scientific Reasoning Skills Test can be used as a valid and reliable measurement tool. © 2018, Ankara University. All rights reserved

Meiotic cellular rejuvenation is coupled to nuclear remodeling in budding yeast.

Production of healthy gametes in meiosis relies on the quality control and proper distribution of both nuclear and cytoplasmic contents. Meiotic differentiation naturally eliminates age-induced cellular damage by an unknown mechanism. Using time-lapse fluorescence microscopy in budding yeast, we found that nuclear senescence factors - including protein aggregates, extrachromosomal ribosomal DNA circles, and abnormal nucleolar material - are sequestered away from chromosomes during meiosis II and subsequently eliminated. A similar sequestration and elimination process occurs for the core subunits of the nuclear pore complex in both young and aged cells. Nuclear envelope remodeling drives the formation of a membranous compartment containing the sequestered material. Importantly, de novo generation of plasma membrane is required for the sequestration event, preventing the inheritance of long-lived nucleoporins and senescence factors into the newly formed gametes. Our study uncovers a new mechanism of nuclear quality control and provides insight into its function in meiotic cellular rejuvenation

Image Analysis for Cystic Fibrosis: Computer-Assisted Airway Wall and Vessel Measurements from Low-Dose, Limited Scan Lung CT Images

Cystic fibrosis (CF) is a life-limiting genetic disease that affects approximately 30,000 Americans. When compared to those of normal children, airways of infants and young children with CF have thicker walls and are more dilated in high-resolution computed tomographic (CT) imaging. In this study, we develop computer-assisted methods for assessment of airway and vessel dimensions from axial, limited scan CT lung images acquired at low pediatric radiation doses. Two methods (threshold- and model-based) were developed to automatically measure airway and vessel sizes for pairs identified by a user. These methods were evaluated on chest CT images from 16 pediatric patients (eight infants and eight children) with different stages of mild CF related lung disease. Results of threshold-based, corrected with regression analysis, and model-based approaches correlated well with both electronic caliper measurements made by experienced observers and spirometric measurements of lung function. While the model-based approach results correlated slightly better with the human measurements than those of the threshold method, a hybrid method, combining these two methods, resulted in the best results

Determination of plasma vitellogenin levels and localization of vitellogenin in liver of Lake Van pearl mullet (Chalcalburnus tarichi Pallas, 1811)

This study focused on hepatosomatic and gonadosomatic index and levels of plasma 17β-estradiol (E2), vitellogenin (Vtg) and total protein and determined the localization of Vtg in the liver during vitellogenesis in female Chalcalburnus tarichi, an endemic cyprinid species living in the Lake Van, Turkey. The levels of plasma E2, Vtg and total protein in female fish increased during vitellogenesis and they are positively correlated with each other. According to the results from the female fish, the lowest levels of E2 and Vtg were measured in December at 120.60±23.38 pg ml^-1 and 1.10±0.26 mg ml^-1, respectively. The highest levels of plasma E2 and Vtg were in May (833.40±211.58 pg ml^-1) and April (31.31±4.9 mg ml^-1), respectively. The Vtg-positive hepatocytes were not uniform in liver of fishes. Generally, the hepatocytes surrounding the portal and central veins were strongly Vtg positive. These results showed that plasma Vtg levels in female fish increased during vitellogenesis related to plasma E2 and gonadosomatic index

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

The Effect of the Pairing Interaction on the Energies of Isobar Analog Resonances in 112−124^{112-124}Sb and Isospin Admixture in 100−124^{100-124}Sn Isotopes

In the present study, the effect of the pairing interaction and the isovector correlation between nucleons on the properties of the isobar analog resonances (IAR) in $^{112-124}$Sb isotopes and the isospin admixture in $^{100-124}$Sn isotopes is investigated within the framework of the quasiparticle random phase approximation (QRPA). The form of the interaction strength parameter is related to the shell model potential by restoring the isotopic invariance of the nuclear part of the total Hamiltonian. In this respect, the isospin admixtures in the $^{100-124}$Sn isotopes are calculated, and the dependence of the differential cross section and the volume integral $J_{F}$ for the Sn($^{3}$He,t)Sb reactions at E($^{3}$He)$=200$ MeV occurring by the excitation of IAR on mass number A is examined. Our results show that the calculated value for the isospin mixing in the $^{100}$Sn isotope is in good agreement with Colo et al.'s estimates $(4-5$, and the obtained values for the volume integral change within the error range of the value reported by Fujiwara et al. (53$\pm$5 MeV fm$^{3}$). Moreover, it is concluded that although the differential cross section of the isobar analog resonance for the ($^{3}$He,t) reactions is not sensitive to pairing correlations between nucleons, a considerable effect on the isospin admixtures in $N\approx Z$ isotopes can be seen with the presence of these correlations.Comment: 16 pages, 5 EPS figures and 2 tables, Late