New models for droplet heating and evaporation

A brief summary of new models for droplet heating and evaporation, developed mainly at the Sir Harry Ricardo Laboratory of the University of Brighton during 2011-2012, is presented. These are hydrodynamic models for mono-component droplet heating and evaporation, taking into account the effects of the moving boundary due to evaporation, hydrodynamic models of multi-component droplet heating and evaporation, taking and not taking into account the effects of the moving boundary, new kinetic models of mono-component droplet heating and evaporation, and a model for mono-component droplet evaporation, based on molecular dynamics simulation. The results, predicted by the new models are compared with experimental data and the prehctions of the previously developed models where possible

Characteristic properties of Planacon MCP-PMTs

A systematic investigation of Planacon MCP-PMTs was performed using 64 XP85002/ FIT-Q photosensors. These devices are equipped with microchannel plates of reduced resistance. Results of a study of their gain stability over time and saturation level in terms of the average anode current are presented. This information allows one to determine the lower limit of the MCP resistance for stable Planacon operation. The spread of the electron multiplication characteristics for the entire production batch is also presented, indicating the remarkably low voltage requirements of these MCP-PMTs. Detection efficiency and noise characteristics, such as dark count rate and afterpulsing level, are also reviewed.Peer reviewe

Some general properties of the renormalized stress-energy tensor for static quantum states on (n+1)-dimensional spherically symmetric black holes

We study the renormalized stress-energy tensor (RSET) for static quantum states on (n+1)-dimensional, static, spherically symmetric black holes. By solving the conservation equations, we are able to write the stress-energy tensor in terms of a single unknown function of the radial co-ordinate, plus two arbitrary constants. Conditions for the stress-energy tensor to be regular at event horizons (including the extremal and ``ultra-extremal'' cases) are then derived using generalized Kruskal-like co-ordinates. These results should be useful for future calculations of the RSET for static quantum states on spherically symmetric black hole geometries in any number of space-time dimensions.Comment: 9 pages, no figures, RevTeX4, references added, accepted for publication in General Relativity and Gravitatio

Fissure Seal or Fluoride Varnish? A Randomized Trial of Relative Effectiveness

Fissure sealant (FS) and fluoride varnish (FV) are effective in preventing dental caries when compared with a no-treatment control. However, the relative clinical effectiveness of these interventions is uncertain. The objective of the study was to compare the clinical effectiveness of FS and FV in preventing dental caries in first permanent molars (FPMs) in 6- to 7-y-olds. The study design was a randomized clinical trial, with 2 parallel arms. The setting was a targeted-population program that used mobile dental clinics in schools located within areas of high social and economic deprivation in South Wales. A total of 1,016 children were randomized 1:1 to receive either FS or FV. Resin-based FS was applied to caries-free FPMs and maintained at 6-mo intervals. FV was applied at baseline and at 6-mo intervals for 3 y. The main outcome measures were the proportion of children developing caries into dentine (D4-6MFT) on any 1 of up to 4 treated FPMs after 36 mo. At 36 mo, 835 (82%) children remained: 417 in the FS arm and 418 in the FV arm. A smaller proportion of children who received FV (n = 73, 17.5%) versus FS (n = 82, 19.6%) developed caries into dentine on at least 1 FPM (odds ratio [OR] = 0.84; 95% CI, 0.59 to 1.21; P = 0.35), a nonstatistically significant difference between FS and FV treatments. The results were similar when the number of newly decayed teeth (OR = 0.86; 95% CI, 0.60 to 1.22) and tooth surfaces (OR = 0.85; 95% CI, 0.59 to 1.21) were examined. In a community oral health program, semiannual application of FV resulted in caries prevention that was not significantly different from that obtained by applying and maintaining FS after 36 mo (EudraCT: 2010-023476-23; ISRCTN: ISRCTN17029222)

Milagro limits and HAWC sensitivity for the rate-density of evaporating Primordial Black Holes

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Os dividendos como estratégia de investimentos em ações

Na Teoria de Finanças, o papel dos dividendos nas cotações é um tema controverso, uma vez que há diferentes teorias que abordam sua relevância para o valor das ações e, em conseqüência, para a riqueza dos acionistas. Além disso, as descobertas empíricas que originaram a Hipótese de Mercado Eficiente de Capitais (HME) não apenas contradizem a Análise Técnica, mas também impõem um desafio à declarada habilidade superior da Análise Fundamentalista em gerar retornos superiores, com base em fatores ou variáveis contábeis, financeiros e econômicos, tais como o dividend yield (retorno em dividendos). A fim de se verificar a relação entre dividend yields e as taxas de retornos das ações, bem como a viabilidade de uma estratégia baseada em dividend yields históricos de "bater" o mercado, foram construídas, mensalmente, durante o período que vai do Plano Real em julho de 1994 a dezembro de 1999, três diferentes carteiras (alto, baixo e zero). Seus riscos, retornos e indicadores de desempenho ajustados ao risco foram calculados e comparados entre si e com seu paradigma (benchmark), o Índice da Bolsa de Valores de São Paulo - Ibovespa. A evidência empírica é incapaz de sugerir que as ações de altos dividend yield tendem a possuir maiores ou menores taxas de retorno do que as ações de baixo ou zero yield. Ademais, as evidências sugerem que não é possível demonstrar, usando o método empírico aplicado, uma clara associação entre dividend yield e taxas de retorno das ações.In Finance Theory, the role of dividends in stock prices is a controversial issue, considering the different theories that exist on their relevance for stock value and, consequently, for shareholders' wealth. Furthermore, empirical findings that have originated the Efficient Market Hypothesis (EMH) not only contradict Technical Analysis, but also pose a challenge to the Fundamental Analysis' supposedly superior ability to generate higher returns based on accounting, financial and economic factors or variables such as the dividend yield. In order to assess the relationship between dividend yields and stocks returns as well as the viability of a strategy based on historic dividend yield to "beat" the market, with reference to the period from the beginning of the Real Plan in July 1994 until December 1999, three different yield portfolios (high, low and zero) were formed on a monthly basis.Their risks, returns and risk-adjusted portfolio performance measurements were calculated, and then compared both among themselves and to the benchmark (São Paulo Stock Exchange Index - Ibovespa). Empirical evidence is unable to suggest either that stocks with a high dividend yield tend to have higher or lower returns than those with a low or zero yield. Moreover, the evidences suggest that, using the applied empirical method, no clear association between dividend yield and stock returns can be demonstrated

A local human Vδ1 T cell population is associated with survival in nonsmall-cell lung cancer

Murine tissues harbor signature γδ T cell compartments with profound yet differential impacts on carcinogenesis. Conversely, human tissue-resident γδ cells are less well defined. In the present study, we show that human lung tissues harbor a resident Vδ1 γδ T cell population. Moreover, we demonstrate that Vδ1 T cells with resident memory and effector memory phenotypes were enriched in lung tumors compared with nontumor lung tissues. Intratumoral Vδ1 T cells possessed stem-like features and were skewed toward cytolysis and helper T cell type 1 function, akin to intratumoral natural killer and CD8+ T cells considered beneficial to the patient. Indeed, ongoing remission post-surgery was significantly associated with the numbers of CD45RA−CD27− effector memory Vδ1 T cells in tumors and, most strikingly, with the numbers of CD103+ tissue-resident Vδ1 T cells in nonmalignant lung tissues. Our findings offer basic insights into human body surface immunology that collectively support integrating Vδ1 T cell biology into immunotherapeutic strategies for nonsmall cell lung cancer

Delayed mucosal antiviral responses despite robust peripheral inflammation in fatal COVID-19

Background While inflammatory and immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in peripheral blood are extensively described, responses at the upper respiratory mucosal site of initial infection are relatively poorly defined. We sought to identify mucosal cytokine/chemokine signatures that distinguished coronavirus disease 2019 (COVID-19) severity categories, and relate these to disease progression and peripheral inflammation. Methods We measured 35 cytokines and chemokines in nasal samples from 274 patients hospitalized with COVID-19. Analysis considered the timing of sampling during disease, as either the early (0–5 days after symptom onset) or late (6–20 days after symptom onset) phase. Results Patients that survived severe COVID-19 showed interferon (IFN)-dominated mucosal immune responses (IFN-γ, CXCL10, and CXCL13) early in infection. These early mucosal responses were absent in patients who would progress to fatal disease despite equivalent SARS-CoV-2 viral load. Mucosal inflammation in later disease was dominated by interleukin 2 (IL-2), IL-10, IFN-γ, and IL-12p70, which scaled with severity but did not differentiate patients who would survive or succumb to disease. Cytokines and chemokines in the mucosa showed distinctions from responses evident in the peripheral blood, particularly during fatal disease. Conclusions Defective early mucosal antiviral responses anticipate fatal COVID-19 but are not associated with viral load. Early mucosal immune responses may define the trajectory of severe COVID-19

Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely