Unusual magnetic and transport properties in HoMn6_6Sn6_6 kagome magnet

With intricate lattice structures, kagome materials are an excellent platform to study various fascinating topological quantum states. In particular, kagome materials, revealing large responses to external stimuli such as pressure or magnetic field, are subject to special investigation. Here, we study the kagome-net HoMn$_6$Sn$_6$ magnet that undergoes paramagnetic to ferrimagnetic transition (below 376 K) and reveals spin-reorientation transition below 200 K. In this compound, we observe the topological Hall effect and substantial contribution of anomalous Hall effect above 100 K. We unveil the pressure effects on magnetic ordering at a low magnetic field from the pressure tunable magnetization measurement. By utilizing high-resolution angle-resolved photoemission spectroscopy, Dirac-like dispersion at the high-symmetry point K is revealed in the vicinity of the Fermi level, which is well supported by the first-principles calculations, suggesting a possible Chern-gapped Dirac cone in this compound. Our investigation will pave the way to understand the magneto-transport and electronic properties of various rare-earth-based kagome magnets

Predicting the potential distribution and habitat variables associated with pangolins in Nepal

Pangolins are highly-threatened due to illegal hunting and poaching, and by the loss, degradation, and fragmentation of their habitats. In Nepal, effective conservation actions for pangolins are scarce due to limited information on the distribution of pangolins in many areas of the country. To identify the nationwide distribution of pangolins in Nepal, and assess the environmental variables associated with their habitat, we conducted an extensive literature review to collate data from previous studies, canvassed information from key informant interviews and expert opinion, and conducted transect surveys and sign surveys. The occurrence of pangolins was recorded based on sightings and indirect signs (such as burrows, digs, tracks, and scats) along 115 belt transects of 500-m length with a fixed width of 50-m, and habitat parameters were surveyed using 347 quadrats of 10 m*10 m. Pangolin presence was confirmed from 61 out of 75 districts from the eastern to the far western parts of the country. The highest frequency of burrows (74%) was observed in the forested habitat constituting brown soil with medium texture (0.02–2 mm) within an elevation range of 500–1500 m above sea level. Logistic regression suggested that the occurrence of pangolin was highly influenced by ground cover and canopy cover of 50–75%, litter depth, and the distance to termite mounds and roads. We used 4136 occurrence GPS points of pangolin burrows that were compiled and collected from the literature review and field surveys in order to predict the potential habitat distribution of pangolin using maximum entropy algorithm (MaxEnt 3.4.1). The model predicted 15.2% (22,393 km2) of the total land of Nepal as potentially suitable habitat for pangolin, with 38.3% (8574 km2) of potential habitat in the eastern region, followed by 37.6% (8432 km2) in the central and 24.1% (5,387 km2) in the western regions. The results of this study present a national baseline for pangolin distribution and serve as an important document for developing and executing conservation actions and management plans for the long-term conservation of pangolins in Nepal

Extreme ultraviolet time- and angle-resolved photoemission setup with 21.5 meV resolution using high-order harmonic generation from a turn-key Yb:KGW amplifier

Characterizing and controlling electronic properties of quantum materials require direct measurements of nonequilibrium electronic band structures over large regions of momentum space. Here, we demonstrate an experimental apparatus for time- and angle-resolved photoemission spectroscopy using high-order harmonic probe pulses generated by a robust, moderately high power (20 W) Yb:KGW amplifier with a tunable repetition rate between 50 and 150 kHz. By driving high-order harmonic generation (HHG) with the second harmonic of the fundamental 1025 nm laser pulses, we show that single-harmonic probe pulses at 21.8 eV photon energy can be effectively isolated without the use of a monochromator. The on-target photon flux can reach 5 × 1010 photons/s at 50 kHz, and the time resolution is measured to be 320 fs. The relatively long pulse duration of the Yb-driven HHG source allows us to reach an excellent energy resolution of 21.5 meV, which is achieved by suppressing the space-charge broadening using a low photon flux of 1.5 × 108 photons/s at a higher repetition rate of 150 kHz. The capabilities of the setup are demonstrated through measurements in the topological semimetal ZrSiS and the topological insulator Sb2−xGdxTe3

Economics of climate change in the water sector in Nepal : a stakeholder-focused approach; a case study of the Rupa Watershed, Kaski, Nepal

Nepal’s National Adaptation Programme of Action (NAPA) shows the watershed area is vulnerable to climate change, with landslides a particular concern. The region in general has experienced increased temperatures and erratic and intense rainfall. The main objective of the study was to explore the options for managing Rupa Lake even under the extreme conditions of climate change, through implementing adaptation measures as chosen by local stakeholders. Two options were presented for cost-benefit analyses: construction of gabion check dams in the river, and construction of an earth-fill dam in the lake. The Rupa Watershed is typical of mountain ecosystems

Resource Management and Model Personalization for Federated Learning over Wireless Edge Networks

Client and Internet of Things devices are increasingly equipped with the ability to sense, process, and communicate data with high efficiency. This is resulting in a major shift in machine learning (ML) computation at the network edge. Distributed learning approaches such as federated learning that move ML training to end devices have emerged, promising lower latency and bandwidth costs and enhanced privacy of end users’ data. However, new challenges that arise from the heterogeneous nature of the devices’ communication rates, compute capabilities, and the limited observability of the training data at each device must be addressed. All these factors can significantly affect the training performance in terms of overall accuracy, model fairness, and convergence time. We present compute-communication and data importance-aware resource management schemes optimizing these metrics and evaluate the training performance on benchmark datasets. We also develop a federated meta-learning solution, based on task similarity, that serves as a sample efficient initialization for federated learning, as well as improves model personalization and generalization across non-IID (independent, identically distributed) data. We present experimental results on benchmark federated learning datasets to highlight the performance gains of the proposed methods in comparison to the well-known federated averaging algorithm and its variants

Comparative analysis of soil organic matter fractions, lability, stability ratios, and carbon management index in various land use types within bharatpur catchment, Chitwan District, Nepal

Abstract Background Land use and land cover changes have a significant impact on the dynamics of soil organic matter (SOM) and its fractions, as well as on overall soil health. This study conducted in Bharatpur Catchment, Chitwan District, Nepal, aimed to assess and quantify variations in total soil organic matter (TSOMC), labile organic matter fraction (CL), stable organic matter fraction (CS), stability ratio (SR), and carbon management index (CMI) across seven land use types: pastureland, forestland, fruit orchards, small-scale conventional agricultural land, large-scale conventional agricultural land, large-scale alternative fallow and conventional agricultural land, and organic farming agricultural land. The study also explored the potential use of the Carbon Management Index (CMI) and stability ratio (SR) as indicators of soil degradation or improvement in response to land use changes. Results The findings revealed significant differences in mean values of TSOMC, CL, and CS among the different land use types. Forestland and organic farming exhibited significantly higher TSOMC (3.24%, 3.12%) compared to fruit orchard lands (2.62%), small scale conventional farming (2.22%), alternative fallow and conventional farming (2.06%), large scale conventional farming (1.84%) and pastureland (1.20%). Organic farming and Forestland also had significantly higher CL (1.85%, 1.84%) and CS (1.27%, 1.39%) compared to all other land use types. Forest and organic farming lands showed higher CMI values, while pastures and forests exhibited higher SR values compared to the rest of the land use types. Conclusions This study highlights the influence of various land use types on soil organic matter pools and demonstrates the potential of CMI and SR as indicators for assessing soil degradation or improvement in response to land use and land cover changes

Extreme ultraviolet time- and angle-resolved photoemission setup with 21.5 meV resolution using high-order harmonic generation from a turn-key Yb:KGW amplifier

Characterizing and controlling electronic properties of quantum materials require direct measurements of nonequilibrium electronic band structures over large regions of momentum space. Here, we demonstrate an experimental apparatus for time- and angle-resolved photoemission spectroscopy using high-order harmonic probe pulses generated by a robust, moderately high power (20 W) Yb:KGW amplifier with a tunable repetition rate between 50 and 150 kHz. By driving high-order harmonic generation (HHG) with the second harmonic of the fundamental 1025 nm laser pulses, we show that single-harmonic probe pulses at 21.8 eV photon energy can be effectively isolated without the use of a monochromator. The on-target photon flux can reach 5 × 1010 photons/s at 50 kHz, and the time resolution is measured to be 320 fs. The relatively long pulse duration of the Yb-driven HHG source allows us to reach an excellent energy resolution of 21.5 meV, which is achieved by suppressing the space-charge broadening using a low photon flux of 1.5 × 108 photons/s at a higher repetition rate of 150 kHz. The capabilities of the setup are demonstrated through measurements in the topological semimetal ZrSiS and the topological insulator Sb2−xGdxTe3.</p