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Upper Indus Basin (UIB) is critical for Pakistan's economy as it is glacial in composition and snow melt that provides 80% of the fresh water to Indus River. Decadal fluctuations in the precipitation in UIB during 1980-2010, using interpolation technique in Arc Map were explored in present study. The results provided a positive correlation between the winter precipitation and summer runoff in middle elevation basins of UIB. The map of decadal difference of mean annual rainfall (1980-2010), prepared in Arc Geographic Information System 9.0, revealed that around Gilgit, Skardu, Astore, Chilas and Bunji, was found the least difference in mean annual rainfall, i.e. of -1.68 to-2.14mm, whereas area around Kakul experienced maximum rainfall decadal difference ranged from -13.63 to -17.45mm. The study suggested that south of lesser Himalayan areas experienced maximum rainfall variability during the period 1980-2010, whereas, lesser variability in north of Himalayan areas inferred safer addition in fresh water in Indus from its glacial reserve. [ABSTRACT FROM AUTHOR]

This study was aimed at exploring the temperature fluctuations in the Upper Indus Basin (UIB) and to find any correlation between the temperature fluctuations with the flow of the Indus water. Correlation between summer temperature and runoff of Indus at Besham Qilla gauging station was performed in Statistical Package for the Social Sciences (SPSS), while the map of decadal difference of mean annual temperature in UIB for the period of 1980-2010 was prepared in Arc Geographic Information Systems (GIS) 9.0. The results proved a negative correlation between the two variables of summer temperature and runoff, with a Pearson Correlation value of -.004, in the middle elevation basins of ephemeral snow of UIB. The decadal temperature variance map proved that extreme northern UIB lies in region experiencing decadal variance between -0.30°C to 0.16°C. The map also indicated a 0.4°C rising trend of temperature in areas around Kakul and Astore. This rising trend could lead to increase flow and sedimentation rates of Indus. Such fluctuations in temperature trends of UIB were critical since this region served as the freshwater reserve of our country. [ABSTRACT FROM AUTHOR]

Dirac and Weyl semimetals are 3D analogues of graphene in which crystalline symmetry protects the nodes against gap formation. Na3Bi and Cd3As2 were predicted to be Dirac semimetals, and recently confirmed to be so by photoemission experiments. Several novel transport properties in a magnetic field have been proposed for Dirac semimetals. Here, we report a property of Cd3As2 that was unpredicted, namely a remarkable protection mechanism that strongly suppresses backscattering in zero magnetic field. In single crystals, the protection results in ultrahigh mobility, 9 × 106 cm2 V−1 s−1 at 5 K. Suppression of backscattering results in a transport lifetime 104 times longer than the quantum lifetime. The lifting of this protection by the applied magnetic field leads to a very large magnetoresistance. We discuss how this may relate to changes to the Fermi surface induced by the applied magnetic field. [ABSTRACT FROM AUTHOR]

The electronic structure basis of the extremely large magnetoresistance in layered nonmagnetic tungsten ditelluride has been investigated by angle-resolved photoelectron spectroscopy. Hole and electron pockets of approximately the same size were found at low temperatures, suggesting that carrier compensation should be considered the primary source of the effect. The material exhibits a highly anisotropic Fermi surface from which the pronounced anisotropy of the magnetoresistance follows. A change in the Fermi surface with temperature was found and a high-density-of-states band that may take over conduction at higher temperatures and cause the observed tum-on behavior of the magnetoresistance in WTe2 was identified. [ABSTRACT FROM AUTHOR]

Magnetoresistance is the change in a material's electrical resistance in response to an applied magnetic field. Materials with large magnetoresistance have found use as magnetic sensors, in magnetic memory, and in hard drives at room temperature, and their rarity has motivated many fundamental studies in materials physics at low temperatures. Here we report the observation of an extremely large positive magnetoresistance at low temperatures in the non-magnetic layered transition-metal dichalcogenide WTe2: 452,700 per cent at 4.5 kelvins in a magnetic field of 14.7 teslas, and 13 million per cent at 0.53 kelvins in a magnetic field of 60 teslas. In contrast with other materials, there is no saturation of the magnetoresistance value even at very high applied fields. Determination of the origin and consequences of this effect, and the fabrication of thin films, nanostructures and devices based on the extremely large positive magnetoresistance of WTe2, will represent a significant new direction in the study of magnetoresistivity. [ABSTRACT FROM AUTHOR]

Magnetoresistance is the change in a material's electrical resistance in response to an applied magnetic field. Materials with large magnetoresistance have found use as magnetic sensors, in magnetic memory, and in hard drives at room temperature, and their rarity has motivated many fundamental studies in materials physics at low temperatures. Here we report the observation of an extremely large positive magnetoresistance at low temperatures in the non-magnetic layered transition-metal dichalcogenide WTe2: 452,700 per cent at 4.5 kelvins in a magnetic field of 14.7 teslas, and 13 million per cent at 0.53 kelvins in a magnetic field of 60 teslas. In contrast with other materials, there is no saturation of the magnetoresistance value even at very high applied fields. Determination of the origin and consequences of this effect, and the fabrication of thin films, nanostructures and devices based on the extremely large positive magnetoresistance of WTe2, will represent a significant new direction in the study of magnetoresistivity. [ABSTRACT FROM AUTHOR]

We present an ARPES study of the surface states of Ru2Sn3, a new type of a strong 3D topological insulator (TI). In contrast to currently known 3D TIs, which display two-dimensional Dirac cones with linear isotropic dispersions crossing through one point in the surface Brillouin Zone (SBZ), the surface states on Ru2Sn3 are highly anisotropic, displaying an almost flat dispersion along certain high-symmetry directions. This results in quasi-one dimensional (1D) Dirac electronic states throughout the SBZ that we argue are inherited from features in the bulk electronic structure of Ru2Sn3 where the bulk conduction bands are highly anisotropic. Unlike previous experimentally characterized TIs, the topological surface states of Ru2Sn3 are the result of a d-p band inversion rather than an s-p band inversion. The observed surface states are the topological equivalent to a single 2D Dirac cone at the surface Brillouin zone. [ABSTRACT FROM AUTHOR]

The physical properties of the previously reported superconductor IrGe and the Rh1-xIrxGe solid solution are investigated. IrGe has an exceptionally high superconducting transition temperature (Tc= 4:7 K) among the isostructural 1 : 1 late-metal germanides MGe (M = Rh, Pd, Ir, and Pt). Specific-heat measurements reveal that IrGe has an anomalously low Debye temperature, originating from a low-lying phonon, compared to the other MGe phases. A large jump at Tc in the specific-heat data clearly indicates that IrGe is a strong coupling superconductor. In the Rh1-xIrxGe solid solution, a relationship between an anomalous change in lattice constants and the Debye temperature is observed. We conclude that the unusually high Tc for IrGe is likely due to strong electron-phonon coupling derived from the presence of a low-lying phonon. [ABSTRACT FROM AUTHOR]

A previously unreported compound, Ag0.79VS2, has been synthesized; its structure and elementary properties are reported. Ag0.79VS2 crystallizes in two forms, designated as the α and β, related to the 1s-InTaS2 structure. Single crystal x-ray diffraction shows the α form to have a single layer hexagonal structure with a unit cell of 3.213(3)Å×7.809(6)Å, consisting of layers of edge-shared VS6 triangular prisms separated by layers of Ag. The β form is similar but has an supercell in the basal plane, yielding a unit cell of 5.573(5)Å×7.822(6)Å. Both forms have disordered and displaced silver in the basal plane, but the β form has partial ordering of its silver sublattice and in-plane vanadium trimers. Resistivity measurements show metallic temperature dependence with an unusual hysteresis between 210K and 130K. Magnetic susceptibility measurements show Pauli Paramagnetic behavior. The Seebeck coefficient at 300K is 42µV/K. [ABSTRACT FROM AUTHOR]

ABSTRACT: In Pakistan, wheat is the principal food crop contributing 2.8 GDP in country's economy. For wheat production different factors are responsible, one of them is climate. This study has been carried out in Bahawalnagar, lying in arid zone of Punjab, to investigate the impact of year to year changes in meteorological parameters like rainfall and temperature on wheat production during the wheat cropping season i.e. November-April. This study focused to find out the impact of variation in temperature and rainfall on wheat production. Multiple linear regression model was applied to check out the relationship between the dependent(production) and independent(rainfall, temperature, area) variables. A significant regression equation was found with R2 of.946, thus explaining 94% variance in the response variable. The model was also tested through ANOVA and the significance of p-value was.000. Results concluded a strong denial of relationship of temperature and rainfall variability with wheat production in Bahawalnagar, however a strong relationship between area under cultivation and wheat production nwas identified. [ABSTRACT FROM AUTHOR]

ABSTRACT: The variabilities and changing trends of temperature in the Potohar region have been examined in this study for the period of 1950-2018. Monthly data of mean, maximum and minimum temperature were acquired from Pakistan Meteorological Department (PMD) and slope method was opted to calculate the variation rate of temperature for the period under investigation. The results of the study revealed the rising trend of temperature over the Kanshi catchment in northern Punjab, for the period under study. Trends of maximum temperature significantly increased to a rate of 0.0134 °C/year, while minimum temperature was also found to have increased at the rate of 0.0334 °C/year. Such high rate of temperacture increase can be attributed to settlement expansion an outcome of rapid urbanization, in Jhelum city. In comparison to maximum temperature (Tmax), the rate of increase of minimum temperature was identified to be more rapid. Correspondingly, a sum of 1 to 2°C increase in minimum temperature was observed, in the study area, for the period under study. The identified temperature changes are anticipated to have adverse consequences particularly for the agriculture and livestock sectors and food security in the region. [ABSTRACT FROM AUTHOR]