Hydrofluorocarbons (HFCs) are manufactured for use as substitutes for ozone-depleting substances that are being phased out globally under Montreal Protocol regulations. While HFCs do not deplete ...ozone, many are potent greenhouse gases that contribute to climate change. Here, new global scenarios show that baseline emissions of HFCs could reach 4.0–5.3 GtCO2-eq yr−1 in 2050. The new baseline (or business-as-usual) scenarios are formulated for 10 HFC compounds, 11 geographic regions, and 13 use categories. The scenarios rely on detailed data reported by countries to the United Nations; projections of gross domestic product and population; and recent observations of HFC atmospheric abundances. In the baseline scenarios, by 2050 China (31%), India and the rest of Asia (23%), the Middle East and northern Africa (11%), and the USA (10%) are the principal source regions for global HFC emissions; and refrigeration (40–58%) and stationary air conditioning (21–40%) are the major use sectors. The corresponding radiative forcing could reach 0.22–0.25 W m−2 in 2050, which would be 12–24% of the increase from business-as-usual CO2 emissions from 2015 to 2050. National regulations to limit HFC use have already been adopted in the European Union, Japan and USA, and proposals have been submitted to amend the Montreal Protocol to substantially reduce growth in HFC use. Calculated baseline emissions are reduced by 90% in 2050 by implementing the North America Montreal Protocol amendment proposal. Global adoption of technologies required to meet national regulations would be sufficient to reduce 2050 baseline HFC consumption by more than 50% of that achieved with the North America proposal for most developed and developing countries.
•HFC emissions are projected to contribute significantly to future climate forcing.•New scenarios are formulated for 10 HFCs, 11 geographic regions, and 13 categories.•Amendment to the Montreal Protocol have been submitted to limit HFC use.•New regulations in the EU, USA and Japan are projected to reduce HFC emissions.•The regulations reduce HFC emissions to more than 50% of the amendment proposals.
Abstract Probabilistic computing is a computing scheme that offers a more efficient approach than conventional complementary metal-oxide–semiconductor (CMOS)-based logic in a variety of applications ...ranging from optimization to Bayesian inference, and invertible Boolean logic. The probabilistic bit (or p-bit, the base unit of probabilistic computing) is a naturally fluctuating entity that requires tunable stochasticity; by coupling low-barrier stochastic magnetic tunnel junctions (MTJs) with a transistor circuit, a compact implementation is achieved. In this work, by combining stochastic MTJs with 2D-MoS 2 field-effect transistors (FETs), we demonstrate an on-chip realization of a p-bit building block displaying voltage-controllable stochasticity. Supported by circuit simulations, we analyze the three transistor-one magnetic tunnel junction (3T-1MTJ) p-bit design, evaluating how the characteristics of each component influence the overall p-bit output. While the current approach has not reached the level of maturity required to compete with CMOS-compatible MTJ technology, the design rules presented in this work are valuable for future experimental implementations of scaled on-chip p-bit networks with reduced footprint.
Lung squamous cell carcinoma (LUSC) is a highly heterogeneous cancer that is influenced by etiological agents such as tobacco smoke. Accordingly, transfer RNA-derived fragments (tRFs) are implicated ...in both cancer onset and development and demonstrate the potential to act as targets for cancer treatments and therapies. Therefore, we aimed to characterize tRF expression with respect to LUSC pathogenesis and clinical outcomes. Specifically, we analyzed the effect of tobacco smoke on tRF expression. In order to do so, we extracted tRF read counts from MINTbase v2.0 for 425 primary tumor samples and 36 adjacent normal samples. We analyzed the data in three primary cohorts: (1) all primary tumor samples (425 samples), (2) smoking-induced LUSC primary tumor samples (134 samples), and (3) non-smoking-induced LUSC primary tumor samples (18 samples). Differential expression analysis was performed to examine tRF expression in each of the three cohorts. tRF expression was correlated to clinical variables and patient survival outcomes. We identified unique tRFs in primary tumor samples, smoking-induced LUSC primary tumor samples, and non-smoking-induced LUSC primary tumor samples. In addition, many of these tRFs demonstrated correlations to worse patient survival outcomes. Notably, tRFs in the smoking-induced LUSC and non-smoking-induced LUSC primary tumor cohorts were significantly correlated to clinical variables pertaining to cancer stage and treatment efficacy. We hope that our results will be used to better inform future LUSC diagnostic and therapeutic modalities.
The problem of accelerating cosmic rays is one of fundamental importance, particularly given the uncertainty in the conditions inside the acceleration sites. Here we examine diffusive shock ...acceleration in arbitrary turbulent magnetic fields, constructing a new model that is capable of bridging the gap between the very weak (δB/B0 < 1) and the strong turbulence regimes. To describe the diffusion we provide a quantitative analytical description of the "Bohm exponent" in each regime. We show that our results converge to the well known quasi-linear theory in the weak turbulence regime. In the strong regime, we quantify the limitations of the Bohm-type models. Furthermore, our results account for the anomalous diffusive behavior which has been noted previously. Finally, we discuss the implications of our model in the study of possible acceleration sites in different astronomical objects.
PurposeThe objective of the study was to explore the factors influencing the career decisions of students doing the students' undergraduate (UG) and postgraduate (PG) programmes from urban private ...universities/colleges in the Indian context.Design/methodology/approachCareer decision-making is determined by different factors and is contextual. The present study explores and identifies the prominent factors influencing career decision-making. A pool of 33 questions was developed, and these questions were initially administered to a sample of 233 students. Principal component analysis with Varimax Rotation identified salient factors. In the second study, confirmatory analysis was performed based on the opinion of 304 students.FindingsThe study shows that the student's career deciding factors include (1) career clarity, (2) career exploration, (3) career reward and recognition and (4) career initiative for professional and personal growth.Originality/valueThe study focussed on career-deciding factors for UG and PG students from urban universities/colleges in the Indian context and the findings can be used for planning career counselling interventions.
With no impending global controls on HFCs, the Montreal Protocol offers a near-term path to preserve its climate benefits.
The Montreal Protocol is perhaps the most successful international ...environmental treaty, responsible for global phaseout of the consumption and production of ozone-depleting substances (ODSs), e.g., chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Hydrofluorocarbons (HFCs), which do not destroy stratospheric ozone, were considered long-term substitutes for ODSs and are not controlled by the Montreal Protocol. Because most HFCs are potent greenhouse gases (GHGs), they are included in the Kyoto Protocol. But climate benefits provided by this protocol are limited as they apply only to developed countries and over a short time (2008–2012). As we describe below, with no impending global controls on HFCs, inclusion of HFCs under the Montreal Protocol offers a path, starting in the short term, to preserve the climate benefits already achieved by this protocol.
A large number of algorithms have been developed to classify individuals into discrete populations using genetic data. Recent results show that the information used by both model-based clustering ...methods and principal components analysis can be summarized by a matrix of pairwise similarity measures between individuals. Similarity matrices have been constructed in a number of ways, usually treating markers as independent but differing in the weighting given to polymorphisms of different frequencies. Additionally, methods are now being developed that take linkage into account. We review several such matrices and evaluate their information content. A two-stage approach for population identification is to first construct a similarity matrix and then perform clustering. We review a range of common clustering algorithms and evaluate their performance through a simulation study. The clustering step can be performed either on the matrix or by first using a dimension-reduction technique; we find that the latter approach substantially improves the performance of most algorithms. Based on these results, we describe the population structure signal contained in each similarity matrix and find that accounting for linkage leads to significant improvements for sequence data. We also perform a comparison on real data, where we find that population genetics models outperform generic clustering approaches, particularly with regard to robustness for features such as relatedness between individuals.
ObjectivesThis paper examines the impact of COVID-19 pandemic on a disadvantaged group of financially poor mothers’ mental health conditions in Singapore during the phase of acute COVID-19 ...infection.DesignA mixed-method design is used. We conducted five focus group discussions with interviewers (n=39) who administered a third wave of survey questionnaire to 424 mothers from low-income families between June and September 2020. The focus group discussions gleaned observations by the interviewers on the risk and stress levels of the mothers during the period leading up to the height of COVID-19 pandemic. In addition, survey data from two time points—pre-COVID-19 and post-COVID-19 pandemic height, measuring the relationship of mother’s job loss, income earner loss, marital status, number of children and, permanency of employment and mother’s hope levels with mother’s depression and anxiety were used to triangulate the observations from the focus group discussions.ResultsMajority of the interviewers did not observe any marked increase in stress levels. Correspondingly the quantitative data did not show any significant increase in depression and anxiety scores between wave 2 and 3 results. Qualitative data showed that numerous mothers were able to report different strategies in coping with the financial distress. The government COVID-19 support grants were cited by many as helpful in cushioning the financial stress. Comparing the quantitative measurements, the relationship between loss of income earner and mother’s depression and anxiety was moderated by marital status. In addition, the relationship between mother’s job loss and mother’s depression, as well as loss of income earner and mother’s anxiety, was moderated by mother’s hope.ConclusionWe speculate the relatively stable level of mental health state of financially poor mothers amidst the COVID-19 pandemic to their internal (psychological traits) resilience which is facilitated by the availability of resources in the social milieu through the COVID-19 support grants.
In the present paper, theoretical simulations and experimental observations are used to describe the ion dynamics in a trapped ion mobility spectrometer. In particular, the ion motion, ion ...transmission and mobility separation are discussed as a function of the bath gas velocity, radial confinement, analysis time and speed. Mobility analysis and calibration procedure are reported for the case of sphere-like molecules for positive and negative ion modes. Results showed that a maximal mobility resolution can be achieved by optimizing the gas velocity, radial confinement (RF amplitude) and ramp speed (voltage range and ramp time). The mobility resolution scales with the electric field and gas velocity and R = 100-250 can be routinely obtained at room temperature.
Microglia are the resident, innate immune cells of the central nervous system (CNS) and are critical in managing CNS injuries and infections. Microglia also maintain CNS homeostasis by influencing ...neuronal development, viability, and function. However, aberrant microglial activity and phenotypes are associated with CNS pathology, including autism spectrum disorder (ASD). Thus, improving our knowledge of microglial regulation could provide insights into the maintenance of CNS homeostasis as well as the prevention and treatment of ASD. Control of microglial activity is in part overseen by small, lipid-derived molecules known as endogenous cannabinoids (endocannabinoids). Endocannabinoids are one component of the endocannabinoid system (ECS), which also includes the enzymes that metabolize these ligands, in addition to cannabinoid receptor 1 (CB
) and 2 (CB
). Interestingly, increased ECS signaling leads to an anti-inflammatory, neuroprotective phenotype in microglia. Here, we review the literature and propose that ECS signaling represents a largely untapped area for understanding microglial biology and its relationship to ASD, with special attention paid to issues surrounding the use of recreational cannabis (marijuana). We also discuss major questions within the field and suggest directions for future research.
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