Water quality in the Lisungwi and Kaphamtengo Rivers in Manondo, Central Malawi: Assessment of the impact of artisanal small scale gold mining

Water quality assessment for river systems is important for tracing any changes in quality caused by, among other things, mining  activities. Mining activities can be one of the most impactful sources of water contamination. In Malawi, gold deposits occur in the  basement rocks of the Lisungwi-Manondo region. As a result, a boom in small scale artisanal mining has occurred as residents have  settled in the area. Despite the development of artisanal small scale mining activities, few studies have investigated the water quality of  the main rivers in the region (i.e., the Lisungwi and Kaphamtengo Rivers), upon which local residents are highly dependent for daily use.  This study provides baseline data for water quality in the region. On-site and laboratory measurements were carried out on the river  water samples, to obtain the physio characteristics (e.g. pH, turbidity, electric conductivity) and the major and minor element  concentrations of the river water. The data was compared to the regional geology to establish anthropogenic and/or geological impacts  on the water quality. The river water has a moderate buffering capacity due to its high alkalinity, along with high Ca, Si, Mg, and Cl  concentrations sourced from the gneiss and calcsilicate rocks in the region. Further analysis of the water quality based on the physiochemical parameters, major and trace element concentrations, showed that the river waters were in accordance with guidelines  set by the Malawi Bureau of Standards (MBS) and the World Health Organization (WHO) for river water quality, with all analyzed  parameters being below the stipulated standards. Our results indicated that the regional geology exerts a significant control on water  chemistry, but the mining activities on and along the river water leaves the water in an uncontaminated state

Streaming Target-Speaker ASR with Neural Transducer

Although recent advances in deep learning technology have boosted automatic speech recognition (ASR) performance in the single-talker case, it remains difficult to recognize multi-talker speech in which many voices overlap. One conventional approach to tackle this problem is to use a cascade of a speech separation or target speech extraction front-end with an ASR back-end. However, the extra computation costs of the front-end module are a critical barrier to quick response, especially for streaming ASR. In this paper, we propose a target-speaker ASR (TS-ASR) system that implicitly integrates the target speech extraction functionality within a streaming end-to-end (E2E) ASR system, i.e. recurrent neural network-transducer (RNNT). Our system uses a similar idea as adopted for target speech extraction, but implements it directly at the level of the encoder of RNNT. This allows TS-ASR to be realized without placing extra computation costs on the front-end. Note that this study presents two major differences between prior studies on E2E TS-ASR; we investigate streaming models and base our study on Conformer models, whereas prior studies used RNN-based systems and considered only offline processing. We confirm in experiments that our TS-ASR achieves comparable recognition performance with conventional cascade systems in the offline setting, while reducing computation costs and realizing streaming TS-ASR.Comment: Accepted to Interspeech 202

The mutual relationship between the host immune system and radiotherapy: stimulating the action of immune cells by irradiation

The effects of irradiation on tumor tissue and the host immune system are interrelated. The antitumor effect of irradiation is attenuated in the immunocompromised hosts. In addition, radiation alone positively and negatively influences the host immune system. The positive effects of radiation are summarized by the ability to help induce and enhance tumor-antigen-specific immune responses. The cancer-immunity cycle is a multistep framework that illustrates how the tumor-antigen-specific immune responses are induced and how the induced antigen-specific immune cells exert their functions in tumor tissues. Irradiation affects each step of this cancer-immunity cycle, primarily in a positive manner. In contrast, radiation also has negative effects on the immune system. The first is that irradiation has the possibility to kill irradiated effector immune cells. The second is that irradiation upregulates immunosuppressive molecules in the tumor microenvironment, whereas the third is that irradiation to the tumor condenses immunosuppressor cells in the tumor microenvironment. When used in conjunction with radiotherapy, immune checkpoint inhibitors can further leverage the positive effects of radiation on the immune system and compensate for the negative effects of irradiation, which supports the rationale for the combination of radiotherapy and immune checkpoint inhibitors. In this review, we summarize the preclinical evidence for the reciprocal effects of radiation exposure and the immune system, and up-front topics of the combination therapy of immune checkpoint inhibitors and radiotherapy

Preparation of Ba1-xLnxFeO3-δ and BaFe1-xLnxO3-δ (Ln: trivalent ion) with cubic perovskite structure and random distribution of oxide ion vacancy

Oxides with perovskite structure and random arrangement of oxide ion, such as Ba0.5Sr0.5Fe0.2Co0.8O3-δ, attract much interest as oxygen permeation material. For wide spread of oxygen permeation devices, development of new material without Co is highly desired because of high cost of Co. Recently, we reported that arrangement of oxide ion vacancy in monoclinic BaFeO2.5-δ changes from ordered to random by partial La3+ substitution for Ba2+ site, resulting in cubic perovskite structure and improvement of electrical conductivity [1, 2]. Fujishiro reported preparation of BaFe1-xInxO3-δ with cubic perovskite structure and enhancement of electrical conductivity with In substitution [3]. It is expected that material with higher property may be developed by substitution of other trivalent ion, such as lanthanoid or Y, for Ba- or Fe- site in BaFeO2.5-δ. In this work, preparation of various Ba1-xLnxFeO3-δ and BaFe1-xLnxO3-δ (Ln: trivalent ion) was examined and factors determining substitution site and crystal structure were investigated. The samples of Ba1-xLnxFeO3-δ and BaFe1-xLnxO3-δ were prepared with Pechini method. Each solution of Ba2+, Ln3+ and Fe3+ was mixed with nominal cation composition. After addition of citric acid and ethylene glycol, the solution was heated at about 450 ºC, resulting in precursor. The precursor was calcined at 700 ºC for 24 h in air, followed by 1300 ºC for 10 h in air twice. The crystal structure and lattice constants of the specimens were investigated with X-ray diffraction. The chemical state of Fe and oxygen content of the specimens were evaluated with iodometric titration. Please click Additional Files below to see the full abstract

Social Capital and Post-traumatic Stress Disorder among Heavy Rainfall and Flood Victims in Japan

This study examined the relationship between cognitive/structural social capital and post-traumatic stress disorder (PTSD) among victims of heavy rain and flood. Participants were individuals aged≥18 years affected by the July 2018 heavy rainfall in the cities of Kurashiki and Soja, Japan, and living in temporary housing. We distributed five copies of a questionnaire to 1,991 households and received responses from 1,927 individuals (907 men, 1,008 women, 12 respondents of unspecified sex) in 1,029 households (51.7%). We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between high (vs. low) social capital and PTSD or other outcomes. After covariate adjustment, the odds of having PTSD were lower in participants with high cognitive social capital than those with low cognitive social capital (OR=0.346, 95%CI: 0.263-0.456). Elderly women with higher structural social capital tended to have lower PTSD odds than those with lower structural social capital (OR=0.671, 95%CI: 0.431-1.046). The opposite pattern was observed for elderly men (OR=1.315, 95%CI: 0.792-2.183). Cognitive social capital is a protective factor that may reduce PTSD or promote a favorable PTSD prognosis after heavy rainfall and flood events. The associations between structural social capital and PTSD differ by age and sex

Mercury and cadmium immobilization in potassium-activated geopolymer: the effect of mixing design and heavy metals concentration

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How does end-to-end speech recognition training impact speech enhancement artifacts?

Jointly training a speech enhancement (SE) front-end and an automatic speech recognition (ASR) back-end has been investigated as a way to mitigate the influence of \emph{processing distortion} generated by single-channel SE on ASR. In this paper, we investigate the effect of such joint training on the signal-level characteristics of the enhanced signals from the viewpoint of the decomposed noise and artifact errors. The experimental analyses provide two novel findings: 1) ASR-level training of the SE front-end reduces the artifact errors while increasing the noise errors, and 2) simply interpolating the enhanced and observed signals, which achieves a similar effect of reducing artifacts and increasing noise, improves ASR performance without jointly modifying the SE and ASR modules, even for a strong ASR back-end using a WavLM feature extractor. Our findings provide a better understanding of the effect of joint training and a novel insight for designing an ASR agnostic SE front-end.Comment: 5 pages, 1 figure, 1 tabl

A highly crystalline face-on -conjugated polymer based on alkoxythiophene-flanked benzobisthiazole for organic photovoltaics

The use of noncovalent intramolecular interactions constitutes a powerful design strategy for preparing π-conjugated polymers featuring high backbone coplanarities and thereby high crystallinities. Herein, we report the design and synthesis of an alkoxythiophene-flanked benzobisthiazole (BBTz) as a new building unit for π-conjugated polymers, which was subsequently copolymerized to give a simple BBTz-bithiophene copolymer with alkyl and alkoxy groups (PDBTz2). Owing to the S···O noncovalent intramolecular interactions between the alkoxy oxygens and thiazole sulfurs in BBTz, PDBTz2 showed greater coplanarity and crystallinity than its alkyl counterpart, PDBTz1. Interestingly, the backbone orientation was completely altered from the edge-on orientation observed for PDBTz1 to a face-on orientation for PDBTz2, which is preferable for organic photovoltaics (OPVs). In addition, the electron-donating nature of the alkoxy group increased the HOMO energy level of PDBTz2 compared to that of PDBTz1, which enabled photoinduced hole transfer from a nonfullerene acceptor, Y6, to the polymer. As a result, the short-circuit current density of an organic photovoltaic cell based on PDBTz2 and Y6 was significantly greater than that of a cell based on PDBTz1 and Y6. This study confirmed that alkoxythiophene-flanked BBTz is a promising building unit for high-performance π-conjugated polymers

Utilisation of Cs-contaminated Fukushima soil as natural pozzolan for embedding into k-alkali activated materials

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GaN-nanopillar-based light-emitting diodes directly grown on multi-crystalline Si substrates

For the first time, light-emitting diodes based on gallium nitride nanopillar crystals were prepared directly on a multi-crystalline silicon substrate, which is widely utilized in low-cost solar cells. Several double-hetero-p–n-junction structures were fabricated, and bright light emission was obtained from the diodes. In addition, white-light emission was observed in another diode. The multi-crystalline Si substrate can be added to a candidate substrate to realize practical, novel, large-area light-emitting devices