Viscosity of High Energy Nuclear Fluids

Relativistic high energy heavy ion collision cross sections have been interpreted in terms of almost ideal liquid droplets of nuclear matter. The experimental low viscosity of these nuclear fluids have been of considerable recent quantum chromodynamic interest. The viscosity is here discussed in terms of the string fragmentation models wherein the temperature dependence of the nuclear fluid viscosity obeys the Vogel-Fulcher-Tammann law.Comment: 6 pages, ReVTeX 4 format, two figures, *.eps forma

Impact of annealing on CuInSe2 thin films and its Schottky interface

The room temperature current–voltage (I-V) characteristics of the Al/p-CuInSe2 Schottky Diodes fabricated on thermally evaporated CIS thin films, before and after annealing, were studied. Prior to their diode formation, the undertaken CIS thin films were compared on the basis of structural, morphological and electrical investigations. Wherein, annealed films showed an increase in the grain size and carrier concentration values while decrease in resistivity. I-V analysis of the Schottky diodes depicted decrease in the barrier heights and increase in ideality factors of those formed on annealed films. The diodes, thus, indicated the existence of barrier inhomogenity at the M-S interface. The annealed Schottky diodes also demonstrated better ideality factor values with increased thickness of CIS layer. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2792

Structure, Optical And Electrical Characterization Of Tin Selenide Thin Films Deposited At Room Temperature Using Thermal Evaporation Method

Tin Selenide (SnSe) is an important IV-VI compound semiconducting material used for various devices like memory switching, an efficient solar cell and holographic recording systems. SnSe thin films of the thickness of 100 nm were deposited by thermal evaporation method on a Glass substrate at room temperature. The prepared samples were investigated for structural, compositional, morphological and optical characte-rization respectively by using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission measurements. Thus deposited films showed a good polycrystalline quality having preferred (111) orientation with uniformly distributed spherical grains having size 16nm.The grown film identified as P- types by hot probe method. The films were found to have direct band transition having an optical bandgap (Eg) of 1.92 eV at room temperature. The temperature depended electrical resistivity (ρ) determined by using the two probe method, found to be 390 Ω·m at room temperature. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/952

RACE-OC Project: Rotation and variability in the open cluster M11 (NGC6705)

Rotation and magnetic activity are intimately linked in main-sequence stars of G or later spectral types. The presence and level of magnetic activity depend on stellar rotation, and rotation itself is strongly influenced by strength and topology of the magnetic fields. Open clusters represent especially useful targets to investigate the rotation/activity/age connection. The open cluster M11 has been studied as a part of the RACE-OC project (Rotation and ACtivity Evolution in Open Clusters), which is aimed at exploring the evolution of rotation and magnetic activity in the late-type members of open clusters with different ages. Photometric observations of the open cluster M11 were carried out in June 2004 using LOAO 1m telescope. The rotation periods of the cluster members are determined by Fourier analysis of photometric data time series. We further investigated the relations between the surface activity, characterized by the light curve amplitude, and rotation. We have discovered a total of 75 periodic variables in the M11 FoV, of which 38 are candidate cluster members. Specifically, among cluster members we discovered 6 early-type, 2 eclipsing binaries and 30 bona-fide single periodic late-type variables. Considering the rotation periods of 16 G-type members of the almost coeval 200-Myr M34 cluster, we could determine the rotation period distribution from a more numerous sample of 46 single G stars at an age of about 200-230 Myr and determine a median rotation period P=4.8d. A comparison with the younger M35 cluster (~150 Myr) and with the older M37 cluster (~550 Myr) shows that G stars rotate slower than younger M35 stars and faster than older M37 stars. The measured variation of the median rotation period is consistent with the scenario of rotational braking of main-sequence spotted stars as they age.Comment: Accepted by Astronomy and Astrophysics on Dec 15, 200

Effect of Film Thickness and Annealing on the Structural and Optical Properties of CuInAlSe2 Thin Films

CuIn1 – xAlxSe2 (CIAS) thin films were grown using flash evaporation method by varying the film thickness from 500 nm to 700 nm. Prepared CIAS thin films were annealed at 573 K for one hour in vacuum. The influence of film’s thickness and the annealing temperature were characterized by the X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive analysis of X-ray (EDAX), Optical transmission measurements, and Hall Effect measurement. As the film thickness increases the crystallinity improves and due to that the optical absorption also improves. The further improvement for different thicknesses of CIAS thin films were observed by annealing. The thicker (700 nm) and annealed CIAS thin film shows the crystallite size of 24.3 nm, energy band gap of 1.19 eV, and resistivity of about 9 102 Ω cm. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3532

Characteristics of Aerosol Spectral Optical Depths over Manora Peak, Nainital −- A High Altitude Station in the Central Himalayas

We present, for the first time, spectral behaviour of aerosol optical depths (AODs) over Manora Peak, Nainital located at an altitude of $\sim$ 2 km in the Shivalik ranges of central Himalayas. The observations were carried out using a Multi-Wavelength solar Radiometer during January to December 2002. The main results of the study are extremely low AODs during winter, a remarkable increase to high values in summer and a distinct change in the spectral dependencies of AODs from a relatively steeper spectra during winter to a shallower one in summer. During transparent days, the AOD values lie usually below 0.08 while during dusty (turbid) days, it lies between 0.08 to 0.69 at 0.5 $\mu$m. The average AOD value at 0.5 $\mu$m during winters, particularly in January and February, is $\sim 0.03\pm0.01$. The mean aerosol extinction law at Manora Peak during 2002 is best represented by $0.10 \lambda^{-0.61}$. However during transparent days, which almost covers 40% of the time, it is represented by $0.02 \lambda^{-0.97}$. This value of wavelength exponent, representing reduced coarse concentration and presence of fine aerosols, indicates that the station measures aerosol in the free troposphere at least during part of the year.Comment: 10 pages, 5 figures, significantly shortened, main conclusions unchanged, accepted for publication in Jr. of Geophys. Reasearch - Atmosphere

Genetics- and genomics-based interventions for nutritional enhancement of grain legume crops: status and outlook

Meeting the food demands and ensuring nutritional security of the ever increasing global population in the face of degrading natural resource base and impending climate change is the biggest challenge of the twenty first century. The consequences of mineral/micronutrient deficiencies or the hidden hunger in the developing world are indeed alarming and need urgent attention. In addressing the problems associated with mineral/micronutrient deficiency, grain legumes as an integral component of the farming systems in the developing world have to play a crucial role. For resourcepoor populations, a strategy based on selecting and/or developing grain legume cultivars with grains denser in micronutrients, by biofortification, seems the most appropriate and attractive approach to address the problem. This is evident from the on-going global research efforts on biofortification to provide nutrient-dense grains for use by the poorest of the poor in the developing countries. Towards this end, rapidly growing genomics technologies hold promise to hasten the progress of breeding nutritious legume crops. In conjunction with the myriad of expansions in genomics, advances in other ‘omics’ technologies particularly plant ionomics or ionome profiling open up novel opportunities to comprehensively examine the elemental composition and mineral networks of an organism in a rapid and cost-effective manner. These emerging technologies would effectively guide the scientific community to enrich the edible parts of grain legumes with bioavailable minerals and enhancers/promoters. We believe that the application of these new-generation tools in turn would provide crop-based solutions to hidden hunger worldwide for achieving global nutritional security

TOM40 Mediates Mitochondrial Dysfunction Induced by α-Synuclein Accumulation in Parkinson's Disease.

Alpha-synuclein (α-Syn) accumulation/aggregation and mitochondrial dysfunction play prominent roles in the pathology of Parkinson's disease. We have previously shown that postmortem human dopaminergic neurons from PD brains accumulate high levels of mitochondrial DNA (mtDNA) deletions. We now addressed the question, whether alterations in a component of the mitochondrial import machinery -TOM40- might contribute to the mitochondrial dysfunction and damage in PD. For this purpose, we studied levels of TOM40, mtDNA deletions, oxidative damage, energy production, and complexes of the respiratory chain in brain homogenates as well as in single neurons, using laser-capture-microdissection in transgenic mice overexpressing human wildtype α-Syn. Additionally, we used lentivirus-mediated stereotactic delivery of a component of this import machinery into mouse brain as a novel therapeutic strategy. We report here that TOM40 is significantly reduced in the brain of PD patients and in α-Syn transgenic mice. TOM40 deficits were associated with increased mtDNA deletions and oxidative DNA damage, and with decreased energy production and altered levels of complex I proteins in α-Syn transgenic mice. Lentiviral-mediated overexpression of Tom40 in α-Syn-transgenic mice brains ameliorated energy deficits as well as oxidative burden. Our results suggest that alterations in the mitochondrial protein transport machinery might contribute to mitochondrial impairment in α-Synucleinopathies

RACE-OC Project: Rotation and variability in the open cluster NGC2099 (M37)

Rotation and solar-type magnetic activity are closely related to each other in stars of G or later spectral types. Presence and level of magnetic activity depend on star's rotation and rotation itself is strongly influenced by strength and topology of the magnetic fields. Open clusters represent especially useful targets to investigate the connection between rotation and activity. The open cluster NGC2099 has been studied as a part of the RACE-OC project, which is aimed at exploring the evolution of rotation and magnetic activity in the late-type members of open clusters of different ages. Time series CCD photometric observations of this cluster were collected during January 2004. The relations between activity manifestations, such as the light curve amplitude, and global stellar parameters are investigated. We have discovered 135 periodic variables, 122 of which are candidate cluster members. Determination of rotation periods of G- and K-type stars has allowed us to better explore evolution of angular momentum at an age of about 500 Myr. A comparison with the older Hyades cluster (~625 Myr) shows that the newly determined distribution of rotation periods is consistent with the scenario of rotational braking of main-sequence spotted stars as they age. However, a comparison with the younger M34 cluster (~200 Myr) shows that the G8-K5 members of these clusters have the same rotation period distribution, that is G8-K5 members in NGC2099 seem to have experienced no significant braking in the age range from ~200 to ~500 Myr. Finally, NGC2099 members have a level of photospheric magnetic activity, as measured by light curve amplitude, smaller than in younger stars of same mass and rotation, suggesting that the activity level also depends on some other age-dependent parameters.Comment: Accepted by A&A 26/02/200

Measurement of the top quark mass using the matrix element technique in dilepton final states

We present a measurement of the top quark mass in pp¯ collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. The data were collected by the D0 experiment corresponding to an integrated luminosity of 9.7  fb−1. The matrix element technique is applied to tt¯ events in the final state containing leptons (electrons or muons) with high transverse momenta and at least two jets. The calibration of the jet energy scale determined in the lepton+jets final state of tt¯ decays is applied to jet energies. This correction provides a substantial reduction in systematic uncertainties. We obtain a top quark mass of mt=173.93±1.84  GeV