Microscopic View on Short-Range Wetting at the Free Surface of the Binary Metallic Liquid Gallium-Bismuth: An X-ray Reflectivity and Square Gradient Theory Study

We present an x-ray reflectivity study of wetting at the free surface of the binary liquid metal gallium-bismuth (Ga-Bi) in the region where the bulk phase separates into Bi-rich and Ga-rich liquid phases. The measurements reveal the evolution of the microscopic structure of wetting films of the Bi-rich, low-surface-tension phase along different paths in the bulk phase diagram. A balance between the surface potential preferring the Bi-rich phase and the gravitational potential which favors the Ga-rich phase at the surface pins the interface of the two demixed liquid metallic phases close to the free surface. This enables us to resolve it on an Angstrom level and to apply a mean-field, square gradient model extended by thermally activated capillary waves as dominant thermal fluctuations. The sole free parameter of the gradient model, i.e. the so-called influence parameter, $\kappa$, is determined from our measurements. Relying on a calculation of the liquid/liquid interfacial tension that makes it possible to distinguish between intrinsic and capillary wave contributions to the interfacial structure we estimate that fluctuations affect the observed short-range, complete wetting phenomena only marginally. A critical wetting transition that should be sensitive to thermal fluctuations seems to be absent in this binary metallic alloy.Comment: RevTex4, twocolumn, 15 pages, 10 figure

Bioactivity of essential oil from Satureja hortensis (Laminaceae) against three stored-product insect species

Human health problems and environmental hazards caused by the indiscriminate use of chemical pesticides during the past three decades, led scientists to look for less persistent and biodegradable alternatives. Essential oils from aromatic plants are recognized as proper alternatives. In this experiment, toxicity of Satureja hortensis essential oil that was isolated via hydrodistillation was investigated against 1 to 7 day-old adults of the red flour beetle, Tribolium castaneum (Herbst), 12 to 14 day-old larvae of the Mediterranean flour moth, Ephestia kuehniella (Zell.) and Indianmeal moth, Plodia interpunctella (Hübner). Repellency of this oil on all the three pest species adults was also studied. After 48 h of exposure, the LC50 value for T. castaneum was 192.35 μl/L. LC50 values were calculated as 80.9 μl/L and 139.8 μl/L after 9 h for E. kuhniella and P. interpunctella, respectively. S. hortensis oil showed more contact toxicity against P. interpunctella (LC50 = 0.19 μl/cm2) than E. kuehniella (LC50 = 0.27 μl/cm2). Repellency of this oil on all the insect species was high. Relationship between exposure time and oil concentration on mortality of all species indicated that mortality was increased by increasing the oil concentration and exposure time.Key words: Tribolium castaneum, Ephestia kuehniell, Plodia interpunctella, repellency, fumigant toxicity, contact toxicity

A subset of platinum-containing chemotherapeutic agents kills cells by inducing ribosome biogenesis stress

Cisplatin and its platinum analogs, carboplatin and oxaliplatin, are some of the most widely used cancer chemotherapeutics. Although cisplatin and carboplatin are used primarily in germ cell, breast and lung malignancies, oxaliplatin is instead used almost exclusively to treat colorectal and other gastrointestinal cancers. Here we utilize a unique, multi-platform genetic approach to study the mechanism of action of these clinically established platinum anti-cancer agents, as well as more recently developed cisplatin analogs. We show that oxaliplatin, unlike cisplatin and carboplatin, does not kill cells through the DNA-damage response. Rather, oxaliplatin kills cells by inducing ribosome biogenesis stress. This difference in drug mechanism explains the distinct clinical implementation of oxaliplatin relative to cisplatin, and it might enable mechanistically informed selection of distinct platinum drugs for distinct malignancies. These data highlight the functional diversity of core components of front-line cancer therapy and the potential benefits of applying a mechanism-based rationale to the use of our current arsenal of anti-cancer drugs

Determinants of burnout in Canadian health care workers during the COVID-19 pandemic

Background: Health care workers (HCWs) are among the most vulnerable groups to experience burnout during the coronavirus (COVID-19) pandemic. Understanding the risk and protective factors of burnout is crucial in guiding the development of interventions; however, the understanding of burnout determinants in the Canadian HCW population remains limited.Objective: Identify risk and protective factors associated with burnout in Canadian HCWs during the COVID-19 pandemic and evaluate organizational factors as moderators in the relationship between COVID-19 contact and burnout.Methods: Data were drawn from an online longitudinal survey of Canadian HCWs collected between 26 June 2020 and 31 December 2020. Participants completed questions pertaining to their well-being, burnout, workplace support and concerns relating to the COVID-19 pandemic. Baseline data from 1029 HCWs were included in the analysis. Independent samples t-tests and multiple linear regression were used to evaluate factors associated with burnout scores.Results: HCWs in contact with COVID-19 patients showed significantly higher likelihood of probable burnout than HCWs not directly providing care to COVID-19 patients. Fewer years of work experience was associated with a higher likelihood of probable burnout, whereas stronger workplace support, organizational leadership, supervisory leadership, and a favourable ethical climate were associated with a decreased likelihood of probable burnout. Workplace support, organizational leadership, supervisory leadership, and ethical climate did not moderate the associations between contact with COVID-19 patients and burnout.Conclusions: Our findings suggest that HCWs who worked directly with COVID-19 patients, had fewer years of work experience, and perceived poor workplace support, organizational leadership, supervisory leadership and ethical climate were at higher risk of burnout. Ensuring reasonable work hours, adequate support from management, and fostering an ethical work environment are potential organizational-level strategies to maintain HCWs’ well-being

Productivity of mixtures and evolutionary populations of wheat, barley, beans and rice

Mixtures of different varieties of barley (Hordeum vulgare), wheat (Triticum ssp.) are grown by farmers in Ethiopia, Iran, Jordan, as a means of diversifying production and/or coping with difficult or uncertain growing conditions. Similarly, mixtures of different varieties of beans (Phaseolus vulgaris) were grown by farmers in Bhutan, Nepal and Uganda, with mixtures of Rice (Oryza sativa) were also grown by Bhutan and Nepal farmers. The mixture of all crops in all countries were grown for three consecutive years under IFAD – EPB project. Varietal diversity can improve farmers’ productivity, capabilities to manage pests and diseases and allows farmers to select suitable cultivars in response to varied or uncertain climatic conditions. Moreover, varietal diversification can improve the nutritional security of smallholder farmers

Dynamic Model of Markets of Successive Product Generations

A dynamic microeconomic model is presented that establishes the price and unit sales evolution of heterogeneous goods consisting of successive homogenous product generations. It suggests that for a fast growing supply the mean price of the generations are governed by a logistic decline towards a floor price. It is shown that generations of a heterogeneous good are in mutual competition. Their market shares are therefore governed by a Fisher-Pry law while the total unit sales are governed by the lifecycle dynamics of the good. As a result the absolute unit sales of a generation exhibit a characteristic sales peak consisting of a rapid increase followed by a long tail. The presented approach shows that the evolution of successive product generations can be understood as an evolutionary adaptation process. The applicability of the model is confirmed by a comparison with empirical investigations on successive DRAM generations.Article no. BJEMT.2047