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Here, the authors report a detailed method of growing LaAlGe, a nonmagnetic Weyl semimetal, thin film on silicon(100) substrates by molecular beam epitaxy and their structural and electrical characterizations. About 50-nm-thick LaAlGe films were deposited and annealed for 16 h in situ at a temperature of 793 K. As-grown high-quality films showed uniform surface topography and near ideal stoichiometry with a body-centered tetragonal crystal structure. Temperature-dependent longitudinal resistivity can be understood with dominant interband s–d electron–phonon scattering in the temperature range of 5–40 K. Hall measurements confirmed the semimetallic nature of the films with an electron-dominated charge carrier density of ~7.15 × 1021 cm−3 at 5 K.
Silicon telluride (Si2Te3) is a silicon-based 2D chalcogenide with potential applications in optoelectronics. It has a unique crystal structure where Si atoms form Si-Si dimers to occupy the “metal” sites. In this paper, we report an ab initio computational study of its optical dielectric properties using the GW approximation and the Bethe-Salpeter equation (BSE). Strong in-plane optical anisotropy is discovered. The imaginary part of the dielectric constant in the direction parallel to the Si-Si dimers is found to be much lower than that perpendicular to the dimers. The optical measurement of the absorption spectra of 2D Si2Te3 nanoplates shows modulation of the absorption coefficient under 90-degree rotation, confirming the computational results. We show the optical anisotropy originates from the particular compositions of the wavefunctions in the valence and conduction bands. Because it is associated with the Si dimer orientation, the in-plane optical anisotropy can potentially be dynamically controlled by electrical field and strain, which may be useful for new device design. In addition, BSE calculations reduce GW quasiparticle band gap by 0.3 eV in bulk and 0.6 eV in monolayer, indicating a large excitonic effect in Si2Te3. Furthermore, including electron-hole interaction in bulk calculations significantly reduces the imaginary part of the dielectric constant in the out-of-plane direction, suggesting strong interlayer exciton effect in Si2Te3 multilayers.
The binary metal oxides are increasingly used as supercapacitor electrode materials in energy storing devices. Particularly NiCo2O4 has shown promising electrocapacitive performance with high specific capacitance and energy density. The electrocapacitive performance of these oxides largely depends on their morphology and electrical properties governed by their energy band-gaps and defects. The morphological structure of NiCo2O4 can be altered via the synthesis route, while the energy band-gap could be altered by doping. Also, doping can enhance crystal stability and bring in grain refinement, which can further improve the much-needed surface area for high specific capacitance. Given the above, this study evaluates the electrochemical performance of Ca-doped Ni1-xCaxCo2O4 (0 ≤ x ≤ 0.8) compounds. This stipulates promising applications for electrodes in future supercapacitors.
The mental health of youth is continually changing and requires reliable monitoring to ensure that adequate social and economic resources are allocated. This study assessed trends in mental health among Canadian youth, 12–24 years old. Specifically, we examined the prevalence of poor/fair perceived mental health, diagnosis of mood and anxiety disorders, suicidality, perceived stress and sleep problems, substance use, and mental health consultations.
Data were collected from eight cycles of the annual Canadian Community Health Survey (2011–2018). Prevalence of mental health outcomes was calculated from each survey, and meta-regression was used to assess trends over time. In the absence of a significant trend over time, the eight cycles were pooled together using meta-analysis techniques to gain precision. Trends in prevalence were assessed for the overall sample of youth (12–24 years) and separately for male and female adolescents (12–18 years) and young adults (19–24 years).
The prevalence of poor/fair perceived mental health, diagnosed mood and anxiety disorders, and past-year mental health consultations increased from 2011 to 2018, most strongly among young adult females. Past-year suicidality increased among young adult females but did not change for other age and sex groups. Notably, the prevalence of binge drinking decreased by 2.4% per year for young adult males, 1.0% for young adult females and 0.7% per year for adolescent males, while staying relatively stable for adolescent females. Prevalence of cannabis use declined among adolescents before legalisation (2011–2017); however, this trend did not persist in 2018. Instead, the 2018 prevalence was 5.6% higher than the 2017 prevalence (16.3 v. 10.7%). The combined prevalence of other illicit drug use was stable at 4.6%; however, cocaine use and hallucinogens increased by approximately 0.2% per year.
Our findings highlight a growing need for youth mental health services, as indicated by a rise in the prevalence of diagnosed mood and anxiety disorders and past-year mental health consultations. The reason for these observed increases is less apparent – it may represent a true rise in the prevalence of mental illness, or be an artefact of change in diagnostic practices, mental health literacy or diminishing stigma. Nonetheless, the findings indicate a need for the health care system to respond to the rising demand for mental health services among youth.
Theoretical calculations and experimental observations show MoTe2 is a type II Weyl semimetal, along with many members of transition metal dichalcogenides family. We have grown highly crystalline large-area MoTe2 thin films on Si/SiO2 substrates by chemical vapor deposition. Very uniform, continuous, and smooth films were obtained as confirmed by scanning electron microscopy and atomic force microscopy analyses. Measurements of the temperature dependence of longitudinal resistivity and current–voltage characteristics at different temperature are discussed. Unsaturated, positive quadratic magnetoresistance of the as-grown thin films has been observed from 10 to 200 K. Hall resistivity measurements confirm the majority charge carriers are hole.
With brown adipose tissue (BAT) becoming a possible therapeutic target to counteract obesity, the prenatal environment could represent a critical window to modify BAT function and browning of white AT. We investigated if levels of uncoupling protein 1 (UCP1) and UCP1-mediated thermogenesis are altered in offspring exposed to prenatal obesity. Female CD-1 mice were fed a high-fat (HF) or standard-fat (SF) diet for 3 months before breeding. After weaning, all pups were placed on SF. UCP1 mRNA and protein levels were quantified using quantitative real-time PCR and Western blot analysis, respectively, in brown (BAT), subcutaneous (SAT) and visceral (VAT) adipose tissues at 6 months of age. Total and UCP1-dependent mitochondrial respiration were determined by high-resolution respirometry. A Student’s t-test and Mann–Whitney test were used (significance: P<0.05). UCP1 mRNA levels were not different between the HF and SF offspring. UCP1 protein levels, total mitochondrial respiration and UCP1-dependent respiration were significantly higher in BAT from HF males (P=0.02, P=0.04, P=0.005, respectively) and females (P=0.01, P=0.04, P=0.02, respectively). In SAT, the UCP1 protein was significantly lower in HF females (P=0.03), and the UCP1-dependent thermogenesis was significantly lower from HF males (P=0.04). In VAT, UCP1 protein levels and UCP1-dependent respiration were significantly lower only in HF females (P=0.03, P=0.04, respectively). There were no differences in total respiration in SAT and VAT. Prenatal exposure to maternal obesity leads to significant increases in UCP1 levels and function in BAT in offspring with little impact on UCP1 levels and function in SAT and VAT.
Questions of state formation and public authority have been at the top of the development and political agenda in Nepal since 2006. The post-2006 so-called ‘political transition’ has been characterized by rising ethnic tensions, violence, strikes, and a bewildering kaleidoscope of leaders gaining political leverage, only to be marginalized again. In 2015, the Constitution was finally adopted following the earthquakes and amid violent protests from groups who felt their needs were marginalized in the final version. In this article we are concerned to probe how struggles over different technologies of government help throw into relief the various terrains within which public authority is claimed and contested, and, as a result, help to expose the limits of the state. Using the forestry sector as an ethnographic lens, we argue that there is both a profound failure by the state to provide services and stable governance as well as an ability to reproduce itself and to function in some contexts. It is therefore important to understand public authority during this period as both stable and unstable—and at times, instability is what helps to perpetuate particular imaginaries of the Nepali state.
Information on density and abundance of globally threatened species such as tigers Panthera tigris is essential for effective conservation as well as to evaluate the success of conservation programmes. We monitored tigers in Parsa Widlife Reserve, Nepal, using camera traps, in 2013, 2014 and 2016. Once believed to be a sink for tigers from adjacent Chitwan National Park, Parsa now provides a new hope for tigers. Spatially explicit capture–recapture analysis over 3 survey years revealed an increase in tiger density from 0.78 to 1.38 individuals per 100 km2 from 2013 to 2016. The tiger abundance was estimated to be seven (6–13), 11 (10–16) and 17 (17–20) in 2013, 2014 and 2016, respectively. Resettlement of communities from the core area, reduced anthropogenic pressure, and improved security have made Parsa Wildlife Reserve a suitable habitat for tigers. Tiger abundance increased considerably within a 5 km radius of the evacuated village sites, from two in 2013 to eight in 2014 and 10 in 2016. Population turnover has remained moderate (< 30% per year), with persistence of individuals in multiple years. Dispersing tigers from Chitwan's source population accounted for a large portion (c. 40%) of the tigers detected in Parsa. Conservation efforts along with annual monitoring should be continued in Parsa to sustain the increase and monitor the persistence of tigers. The Chitwan–Parsa complex should be managed as a single ecological unit for conserving the Endangered tiger and other wide-ranging species.
The objective of the studies presented in this Research Communication was to investigate the association of single nucleotide polymorphisms present in the MAP4K4 gene with different milk traits in dairy cows. Based on previous QTL fine mapping results on bovine chromosome 11, the MAP4K4 gene was selected as a candidate gene to evaluate its effect on somatic cell count and milk traits in ChineseHolstein cows. Milk production traits including milk yield, fat percentage, and protein percentage of each cow were collected using 305 d lactation records. Association between MAP4K4 genotype and different traits and Somatic Cell Score (SCS) was performed using General Linear Regression Model of R. Two SNPs at exon 18 (c.2061T > G and c.2196T > C) with genotype TT in both SNPs were found significantly higher for somatic SCS. We found the significant effect of exon 18 (c.2061T > G) on protein percentage, milk yield and SCS. We identified SNPs at different location of MAP4K4 gene of the cattle and several of them were significantly associated with the somatic cell score and other different milk traits. Thus, MAP4K4 gene could be a useful candidate gene for selection of dairy cattle against mastitis and the identified polymorphisms might potentially be strong genetic markers.
The grey wolf Canis lupus lupus is Critically Endangered in Nepal, and is a protected species there. Understanding the species’ status and distribution is critical for its conservation in the Nepalese Himalaya. We assessed the distribution of the grey wolf in the Himalayan and Trans-Himalayan regions using data from faecal and camera trap surveys and published data sources. We recorded 40 instances of wolf presence. Using these data we estimated a distribution of 28,553 km2, which includes potential as well as known habitat and comprises 73% of the Nepalese Himalaya. There is evidence of recovery of the grey wolf population in Kanchenjunga Conservation Area in the eastern portion of the species’ range. A livestock insurance scheme has been shown to be a viable option to reduce retaliatory killing of wolves as a result of livestock depredation. The wolf plays an important ecological role in the Himalaya, and its conservation should not be delayed by the ongoing taxonomic debate about its subspecific status.
Vegetable legumes are important crops in tropical agriculture, but they are susceptible to a substantial number of arthropod pests and diseases. Using farm-level survey data for 240 farm households growing yard-long bean (Vigna unguiculata subsp. sesquipedalis) in Thailand and Vietnam, this study shows that the farmers' main problem is the legume pod borer (Maruca vitrata). Farmers rely exclusively on the use of synthetic pesticides to manage this pest, and no other control methods are generally applied. Small cultivated areas for growing yard-long bean (particularly in Vietnam), a high level of satisfaction with the use of pesticides and a lack of market demand for pesticide-free produce are formidable challenges to the introduction of integrated pest management (IPM). It is important to ensure that IPM methods, if adopted, do not reduce profits and that farmers are allowed to experiment with these methods while raising awareness in the general population about the risk resulting from pesticide exposure.
Human–wildlife conflict is a significant problem that often results in retaliatory killing of predators. Such conflict is particularly pronounced between humans and tigers Panthera tigris because of fatal attacks by tigers on humans. We investigated the incidence and perception of human–tiger conflict in the buffer zone of Bardia National Park, Nepal, by interviewing 273 local householders and 27 key persons (e.g. representatives of local communities, Park officials). Further information was compiled from the Park's archives. The annual loss of livestock attributable to tigers was 0.26 animals per household, amounting to an annual loss of 2% of livestock. Livestock predation rates were particularly high in areas with low abundance of natural prey. During 1994–2007 12 people were killed and a further four injured in tiger attacks. Nevertheless, local people generally had a positive attitude towards tiger conservation and were willing to tolerate some loss of livestock but not human casualties. This positive attitude indicates the potential for implementation of appropriate conservation measures and we propose mitigation strategies such as education, monetary compensation and monitoring of tigers.
The synthesis of bimetallic magnetic nanoparticles is very challenging because of the agglomeration and non-uniform size. In this paper, we present the synthesis of monodispersed 3-5 nm sized thiolated bimetallic alloyed Au/Co nanoparticles with decahedral and icosahedral shape, their characterization using Cs-corrected scanning transmission electron microscopy (STEM) and magnetic measurements using superconducting quantum interference device (SQUID) magnetometer. The Z-contrast imaging and energy dispersive X-ray spectroscopy (EDS) mapping showed an inhomogeneous alloying with minor segregation between Au and Co at nanoscale and the SQUID measurement exhibited the ferromagnetic behavior.
Monitoring the glacier mass balance of summer-accumulation-type Himalayan glaciers is critical to not only assess the impact of climate change on the volume of such glaciers but also predict the downstream water availability and the global sea-level change in future. To better understand the change in meteorological parameters related to glacier mass balance and runoff in a glacierized basin and to assess the highly heterogeneous glacier responses to climate change in the Nepal Himalaya and nearby ranges, the Cryosphere Monitoring Project (CMP) carries out meteorological observations in Langtang Valley and mass-balance measurements on Yala Glacier, a debris-free glacier in the same valley. A negative annual mass balance of –0.89m w.e. and the rising equilibrium-line altitude of Yala Glacier indicate a continuation of a secular trend toward more negative mass balances. Lower temperature lapse rate during the monsoon, the effect of convective precipitation associated with mesoscale thermal circulation in the local precipitation and the occurrence of distinct diurnal cycles of temperature and precipitation at different stations in the valley are other conclusions of this comprehensive scientific study initiated by CMP which aims to yield multi-year glaciological, hydrological and meteorological observations in the glacierized Langtang River basin.