Carrier Transport in Magnesium Diboride: Role of Nano-inclusions

Anisotropic-gap and two-band effects smear out the superconducting transition (Tc) in literature reported thermal conductivity of MgB2, where large electronic contributions also suppress anomaly-manifestation in their negligible phononic-parts. Present thermal transport results on scarcely explored specimens featuring nano-inclusions exhibit a small but clear Tc-signature, traced to relatively appreciable phononic conduction, and its dominant electronic-scattering. The self-formed MgO as extended defects strongly scatter the charge carriers and minutely the phonons with their longer-mean-free-path near Tc. Conversely, near room temperature, the shorter-dominant-wavelength phonon's transport is hugely affected by these nanoparticles, undergoing ballistic to diffusive crossover and eventually entering the Ioffe-Regel mobility threshold regime.Comment: 14 pages, 4 figures, 28 reference

Poboljšanje uspješnosti prognoze oborine nad Indijom primjenom metode višemodelskog ansambla

In this paper a Multi-Model Ensemble (MM E) technique is experimented for improving day to day rainfall forecast over India in short to medium range time scale during summer monsoon of 2010. Four operational global Numerical Weather Prediction (NWP) models namely, ECMWF, JMA, NCEP GFS and UKMO available on real time basis at India Meteorological Department (IMD), New Delhi are used simultaneously with appropriate weights to obtain the MME Technique. In this technique, weights for each NWP model at each grid point is assigned on the basis of the correlation coefficient (CC) between model forecasts and observed daily rainfall time series of south west monsoon (JJAS) season. Apart from MM E, a simple ensemble mean (ENSM ) forecast are also generated and experimented. The rainfall prediction skill of the weighted MM E is examined against ENSM and member models. The inter-comparison reveals that the weighted MM E is able to provide more accurate forecast of rainfall over Indian monsoon region by taking the strength of each constituent member model. It has been further found that the rainfall prediction skill of MM E is higher as compared to ENSM and member models in the short range time scale. The rainfall prediction skill of weighted MM E technique improved significantly over India.U ovom radu primijenjena je metoda višemodelskog ansambla (MME) s ciljem poboljšanja kratkoročnih do srednjoročnih dnevnih prognoza količine oborine nad Indijom tijekom ljetnog monsuna 2010. godine. pri tome su istovremeno te s odgovarajućim težinama korištena četiri operativna globalna modela za numeričku prognozu vremena (NWP): ECMWF, JMA, NCEP, GFS i UKMO, a koji su na raspolaganju u realnom vremenu pri Indijskom meteorološkom odsjeku (IMD) u New Delhiju. Težine za svaki NWP model u svakoj točki mreže pridijeljene su na temelju koeficijenta korelacije (CC) između modelskih prognoza i mjerenog niza dnevne količine oborine za sezonu jugozapadnog monsuna (od lipnja do rujna). Pored MME, generirane su i ispitane jednostavne prognoze dobivene srednjakom ansambla (ENSM). Uspješnost prognoze količine oborine dobivene MME metodom procijenjena je usporedbom rezultata dobivenih tom metodom i onih na temelju ENSM te sa svakim pojedinačnim modelom. Međusobna usporedba pokazuje da metoda MME točnije prognozira količinu oborine u području indijskog monsuna ponderiranjem doprinosa svakog pojedinog modela u ansamblu. Nadalje, utvrđena je veća uspješnost kratkoročnih prognoza količine oborine pomoću metode mmE u odnosu na rezultate metode ENSM te u odnosu na prognoze pojedinačnih modela ansambla. Primjena ponderirane metode MME značajno poboljšava uspješnost prognoze količine oborine nad Indijom

Effect of lead toxicity on bone calcium content and morphometric parameters

Background: There is large number of pollutants prevailing in the present environment. Among these, lead (Pb) is of particular interest to us because of its wide distribution in the environment. Large existence of lead (Pb) in number of food items has provoked us to investigate the effects of this metal on bone growth in rats. The present study was designed to evaluate the impact of lead poisoning on bone tissue.Methods: A total of 48 male wistar rats and 30 & 80 days of age were selected for this study. Lead (as lead acetate 250 mg/ml) was provided ad libitum in drinking water for about five weeks to produce subclinical toxicity. Glacial acetic acid was added to the drinking water of lead administered groups at a concentration of 12.5 μl/l to prevent the precipitation of lead acetate. At the termination of treatment period, rats from all four groups were sacrificed by decapitation and their long bones i.e. femur and tibia were excised, cleaned off from soft tissue. Then the bones were preserved in refrigerator (-20oC) and processed for further analysis.Results: Our study revealed that Lead significantly reduced calcium concentration in both femur (p<0.001) and tibia (p<0.001) in lead intoxicated rats. Furthermore, morphometric parameters showed significant reduction in the femoral head width upon lead intoxication. Significant decrease in the ash content of both the bones was observed upon lead intoxication for both the age groups, no significant change observed in the length of the femur as well as tibia of all the treated groups.Conclusions: From this study we can conclude that the lead has induced bone toxicity and has deteriorated the development of bone tissue in the case of growing animals, is the consequence of oxidative stress.

Star versions of the Hurewicz basis covering property and strong measure zero spaces

In this paper, we introduced the star version of the Hurewicz basis covering property, studied by Babinkostova, Kočinac, and Scheepers in 2004. The authors obtained the relationship between star-selection principles and the star version of the Hurewicz basis covering property for metrizable spaces. We also consider the star version of Hurewicz measure zero spaces and characterized these new spaces by the star-selection principle related to star-Hurewicz spaces. © TÜBITAK.The authors are thankful to Prof. Lj. D. R. Kocˇinac for his kind help and suggestions. The authors would like to thank the referee for careful reading of this paper. The first author acknowledges the fellowship grant of University Grant Commission, India

Composition of Jupiter irregular satellites sheds light on their origin

Irregular satellites of Jupiter with their highly eccentric, inclined and distant orbits suggest that their capture took place just before the giant planet migration. We aim to improve our understanding of the surface composition of irregular satellites of Jupiter to gain insight into a narrow time window when our Solar System was forming. We observed three Jovian irregular satellites, Himalia, Elara, and Carme, using a medium-resolution 0.8-5.5 micro m spectrograph on the National Aeronautics and Space Administration (NASA) Infrared Telescope Facility (IRTF). Using a linear spectral unmixing model we have constrained the major mineral phases on the surface of these three bodies. Our results confirm that the surface of Himalia, Elara, and Carme are dominated by opaque materials such as those seen in carbonaceous chondrite meteorites. Our spectral modeling of NIR spectra of Himalia and Elara confirm that their surface composition is the same and magnetite is the dominant mineral. A comparison of the spectral shape of Himalia with the two large main C-type asteroids, Themis (D 176 km) and Europa (D 352 km), suggests surface composition similar to Europa. The NIR spectrum of Carme exhibits blue slope up to 1.5 microm and is spectrally distinct from those of Himalia and Elara. Our model suggests that it is compositionally similar to amorphous carbon. Himalia and Elara are compositionally similar but differ significantly from Carme. These results support the hypotheses that the Jupiter irregular satellites are captured bodies that were subject to further breakup events and clustered as families based on their similar physical and surface compositions

Inclusive and exclusive measurements of B decays to χ_{c1} and χ_{c2} at Belle

We report inclusive and exclusive measurements for χc1 and χc2 production in B decays. We measure B(B → χc1X)= (3.03 ± 0.05(stat) ± 0.24(syst)) × 10−3 and B(B → χc2X)= (0.70 ± 0.06(stat) ± 0.10(syst)) × 10−3 . For the first time, χc2 production in exclusive B decays in the modes B 0 → χc2π −K+ and B + → χc2π +π −K+ has been observed, along with first evidence for the B + → χc2π +K0 S decay mode. For χc1 production, we report the first observation in the B + → χc1π +π −K+, B 0 → χc1π +π −K0 S and B 0 → χc1π 0π −K+ decay modes. Using these decay modes, we observe a difference in the production mechanism of χc2 in comparison to χc1 in B decays. In addition, we report searches for X(3872) and χc1(2P) in the B + → (χc1π +π −)K+ decay mode. The reported results use 772 × 106 BB events collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e +e − collider

Mercury toxicity and detection using chromo-fluorogenic chemosensors

Mercury (Hg), this non-essential heavy metal released from both industrial and natural sources entered into living bodies, and cause grievous detrimental effects to the human health and ecosystem. The monitoring of Hg2+ excessive accumulation can be beneficial to fight against the risk associated with mercury toxicity to living systems. Therefore, there is an emergent need of novel and facile analytical approaches for the monitoring of mercury levels in various environmental, industrial, and biological samples. The chromo-fluorogenic chemosensors possess the attractive analytical parameters of low-cost, enhanced detection ability with high sensitivity, simplicity, rapid on-site monitoring ability, etc. This review was narrated to summarize the mercuric ion selective chromo-fluorogenic chemosensors reported in the year 2020. The design of sensors, mechanisms, fluorophores used, analytical performance, etc. are summarized and discussed