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The Himalayan glaciers contribute significantly to regional water resources. However, limited field observations restrict our understanding of glacier dynamics and behaviour. Here, we investigated the long-term in situ mass balance, meteorology, ice velocity and discharge of the Chhota Shigri Glacier. The mean annual glacier-wide mass balance was negative, −0.46 ± 0.40 m w.e. a−1 for the period 2002–2019 corresponding to a cumulative wastage of −7.87 m w.e. Winter mass balance was 1.15 m w.e. a−1 and summer mass balance was −1.35 m w.e. a−1 over 2009–2019. Surface ice velocity has decreased on average by 25–42% in the lower and middle ablation zone (below 4700 m a.s.l.) since 2003; however, no substantial change was observed at higher altitudes. The decrease in velocity suggests that the glacier is adjusting its flow in response to negative mass balance. The summer discharge begins to rise from May and peaks in July, with a contribution of 43%, followed by 38% and 19% in August and September, respectively. The discharge pattern closely follows the air temperature. The long-term observation on the ‘Chhota Shigri – a benchmark glacier’, shows a mass wastage which corresponds to the slowdown of the glacier in the past two decades.
We present the first-ever mass-balance (MB) observation (2014–19), reconstruction (between 1978 and 2019) and sensitivity of debris-free Stok glacier (33.98°N, 77.45°E), Ladakh Region, India. In-situ MB was negative throughout the study period except in 2018/19 when the glacier witnessed a balanced condition. For MB modelling, three periods were considered based on the available data. Period I (1978–87, 1988/89) witnessed a near balance condition (−0.03 ± 0.35 m w.e. a−1) with five positive MB years. Whereas Period II (1998–2002, 2003–09) and III (2011–19) experienced high (−0.9 ± 0.35 m w.e. a−1) and moderate (−0.46 ± 0.35 m w.e. a−1) negative MBs, respectively. Glacier area for these periods was derived from the Corona, Landsat and PlanetScope imageries using a semi-automatic approach. The in-situ and modelled MBs were in good agreement with RMSE of 0.23 m w.e. a−1, R2 = 0.92, P < 0.05. The average mass loss was moderate (−0.47 ± 0.35 m w.e. a−1) over 28 hydrological years between 1978 and 2019. Sensitivity analysis showed that the glacier was more sensitive to summer temperature (−0.32 m w.e. a−1 °C−1) and winter precipitation (0.12 m w.e. a−1 for ± 10%). It was estimated that ~27% increase in precipitation is required on Stok glacier to compensate for the mass loss due to 1°C rise in temperature.
Cold-sprayed high-entropy alloy (HEA) coatings have been generated for the first time. Mechanically alloyed (MA) AlCoCrFeNi powder was chosen as feedstock, owing to the extensive literature on this alloy. Coatings were synthesized under various gas temperature and pressure conditions. Isothermal oxidation was conducted at 1100 °C for 25 h on the coating cold-sprayed at 400 °C and 10 bar on a Ni-base superalloy substrate. The as-sprayed coating retained the MA phases and formed a protective alumina layer upon oxidation. An interdiffusion zone at the interface and unanticipated Mo diffusion from the superalloy substrate into the coating were observed after oxidation. A comprehensive characterization at the coating–substrate interface suggests that diffusion in HEAs is not sluggish. The factors governing the coating’s oxidation are elucidated, and a plausible oxidation mechanism is discussed. These studies are aimed at developing oxidation-resistant HEA coatings for potential applications at high operating temperatures.
In this paper, a miniaturized open-ended dual-band band-pass filter with stepped series capacitance and shunt meandered line inductance for microwave frequency applications has been designed and discussed. In order to offer ease of fabrication and uniplanar configuration, coplanar waveguide feeding arrangement has been used. Zeroth order resonance, a special phenomenon of composite right/left handed transmission line has been utilized to miniaturize the filter size. The designed filter structure offers miniaturization with overall footprint size of 0.26λg × 0.19λg, where λg is the guided wavelength at the center frequency of 1.46 GHz. It offers 58.90% (1.03–1.89 GHz) and 25.93% (2.55–3.31 GHz) measured −3 dB fractional bandwidth with respect to the center frequencies of 1.46 and 2.93 GHz, respectively. Dispersion plot has been utilized to discuss the metamaterial properties for the proposed dual-band band-pass filter. In addition to above, the proposed filter structure presents almost flat group delay curve within both passbands. The proposed filter structure can be suitably utilized for distinct wireless applications, for example global navigation satellite system (1.559–1.610 GHz), GSM1800 (1.7–1.8 GHz), Wi-MAX (2.5–2.7 GHz), and naval radar and air traffic control (2.7–2.9 GHz).
In this paper, a compact metamaterial inspired ultra-thin polarization independent quad-band microwave absorber for electromagnetic interference (EMI)/ electromagnetic compatibility (EMC) applications have been discussed. The proposed absorber structure offers four different absorption peaks having absorptivity of 97.02, 94.07, 91.72, and 98.20% at 3.40, 8.23, 9.89, and 11.80 GHz, respectively. Due to the four-fold symmetry of the designed unit cell, the proposed absorber structure shows polarization independent behavior. In addition to above, the absorption curve for the designed structure has been also analyzed under different angles of incidence for both transverse electric and transverse magnetic polarization states. In order to confirm the metamaterial behavior of the proposed absorber unit cell, dispersion plot has been studied. Further, input impedance plot, electric field, and surface current distribution plot have been discussed to explain the absorption mechanism of the proposed absorber structure. The designed absorber unit cell shows compactness of 0.136 λ0 × 0.136 λ0 with the ultra-thin thickness of 0.0113 λ0, where λ0 (free space wavelength) corresponds to the lowest absorption peak of 3.40 GHz. In order to calculate the measured value of absorptivity, the designed absorber structure has been fabricated. Further, it has been observed that simulated and measured results perfectly match with each other. The ultra-thin and compact nature of the proposed absorber structure suggests its potential use in the field of various EMI/EMC applications.
Interrupted aortic arch is a rare congenital anomaly in newborns and infants and is commonly associated with other cardiovascular anomalies. Here, we report an unusual case of type A interrupted cervical aortic arch associated with long segment coarctation of the descending thoracic aorta. Patent ductus arteriosus reconstituted the descending thoracic aorta. Proximal segments of the left common carotid and left subclavian arteries were atretic. Echocardiography-gated multidetector CT angiography not only identified the type of aortic arch interruption in the neonate but also delineated the exact anatomical details.
Oxyspirura petrowi is a heteroxenous parasitic nematode that has been reported in high prevalences from birds in the Order Galliformes experiencing population declines in the USA. There is a paucity of information regarding the natural history O. petrowi, including the life cycle and effects of infection on wild bird populations. In order to study the life cycle of this parasite, we collected plains lubber grasshoppers (Brachystola magna) from a field location in Mitchell County, Texas. We found third-stage larvae (L3) in 37.9% (66/174) B. magna. We determined that they were O. petrowi through morphological comparison of L3 from experimentally infected Acheta domesticus and by sequence analysis. Then, we showed that B. magna are a potential intermediate hosts for O. petrowi infections in northern bobwhites (Colinus virginianus) in a laboratory setting by experimental infection. We first detected shedding of eggs in feces using a fecal float technique 52 days post infection. In addition, we recovered 87 O. petrowi from experimentally infected northern bobwhites. Although we detected shedding in feces, recovery of eggs was low (>5 eggs/g). Future work is needed to understand shedding routes and shedding patterns of northern bobwhites infected with O. petrowi.
Iron (Fe) and zinc (Zn) contents in hexaploid wheat are very low and are further reduced because of the removal of micronutrient-rich bran of wheat grains during milling and processing. Therefore, hexaploid wheat, its wild species and wheat–Aegilops kotschyi substitution lines were evaluated to identify the genome(s) carrying gene(s) for high Fe and Zn concentrations in bran and endosperm fractions of grains. It is reflected from the results that Triticum monococcum (acc. W463) may serve as a promising donor for biofortification of Fe, and Aegilops speltoides (acc. 3804) may serve as a promising donor for biofortification of Zn in the endosperm of cultivated wheat. Further, among the three wheat–Ae. kotschyi substitution lines, the higher concentration of Fe and Zn in endosperm fraction was observed in BC2F4 63-2-13-1. The work on precise transfer of useful gene(s) from 7Uk chromosome of this line is in progress to reduce linkage drag.
SN 2012AW is a type-IIP supernova which exploded in M95. In this paper we discuss the radio observations of this supernova and model them to determine the important parameters relevant to the explosion and the evolution of blast wave. We also determine the dominant cooling process important to this source.
Background: This retrospective chart review evaluated a comparison of the clinical profiles of older outpatients having mania and those with unipolar depression.
Methods: The charts of elderly outpatients with mania and unipolar depression in tertiary care settings were reviewed and relevant information incorporated regarding clinical presentation, past and family history of affective disorder, treatment history and previous psychiatric and neurological history.
Results: Charts for 30 patients with mania (23 men and 7 women with mean (±SD) age of 68.5(± 5.75 years) and 92 with depression (47 men and 45 women with mean (±SD) age of 68.18 (±6.0 years) were evaluated. Fifteen patients (50%) with manic episodes had psychotic symptoms in the form of delusions and hallucinations while only 33 (35.8%) depressed patients had psychotic symptoms. One-third of manic patients received mood stabilizers at index visit. More than half (n = 16; 53.3%) of the patients in the mania group were prescribed antipsychotic medications. On cognitive functions, patients with manic episodes scored poorly compared with those with depression.
Conclusions: These findings suggest that mania in the elderly is a severe form of affective disorder with respect to psychotic and cognitive symptoms. Conclusions from this study are limited due to its retrospective design. Further studies in this area are warranted.
Polycarbonate (PC) membrane and PC based hydrogen active intermetallic compound Fe0.5Ti0.5 particles doped composite membrane have been prepared by solution cast method. The membranes have been characterized by H2 and CO2 permeability and selectivity measurements with increasing temperature. Higher gas permeation has been observed with increasing temperature. In case of doped composite membrane H2/CO2 gas pair selectivity first increases then decreases with temperature whereas in case of pure PC it decreases with temperature. The effect of doping increases the activation energies for permeation of H2 and CO2 in the doped membrane in comparison to pure PC. Doping was found to suppress plasticization effect in polycarbonate. The doped membrane was analyzed by optical micrograph and XRF study.
A large number of composited materials of atomized iron and multiwalled carbon nanotubes have been prepared and sintered at 850°C for one hour. The sintered samples were examined for thermal and for electrochemical corrosion of atomized iron. The results suggest that the composited materials are free from oxidative degradation. The absence of oxidation of atomized iron in nanocomposited environment is attributed to the configurational geometry and spintronics type interaction proposed in recent theoretical calculations.
Primary tracheal masses are rare. Secondary masses of the trachea are commonly foreign body granuloma, intubation granuloma or viral granuloma. The differential diagnoses given in such cases include both benign and malignant lesions. The otolaryngologist is often asked to perform a biopsy of the lesion to arrive at a diagnosis. However, even malignant processes can cause a granulomatous reaction. The timely diagnosis of tracheal masses depends upon maintaining a high index of suspicion. A rare case of tracheal granuloma leading to pneumomediastinum in a 53-year-old female is presented. The clinical features, investigations and treatment are detailed. The tracheal granuloma was managed by excision through bronchoscopy and the pneumomediastinum was managed conservatively.
The effect of nanostructure on the thermal oxidation of atomized iron has been investigated. Above 500°C atomized iron is oxidized in the presence of air. However, when iron is compacted with multiwalled carbon nanotubes (MWCNT) this oxidation is shifted by more than 100°C. Iron is protected by the nanostructure environment A large number of compositions of atomic ratios of iron and MWCNT have been examined in this study to understand the effect in detail. The effect of nanostructure in the thermal oxidation of iron is interpreted as due to iron atom experiencing extensive overlap and confinement effect. causing spin transfer. Based on theoretical calculations reported in the literature this confinement effect of iron is suggested to produce a transformation from 3d64s2 to an effective configuration of 3d84s0 producing spintronics effect.
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