Holographic technique for measurement of the kinetic constant and optical modulation of photosensitive materials

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We use a holographic technique to measure simultaneously and separately the temporal evolution of the refractive-index and the absorption coefficient modulations induced by light in a photosensitive material. The technique is phase sensitive, allowing separation of the signals from the phase and from the amplitude grating. The refractive-index and the absorption coefficient modulations as well as the kinetic constant of the photoreaction in the positive photoresist SC 1827 were measured at three different wavelengths. The results were compared with independent measurements, performed under homogeneous exposition. The good accord demonstrates the applicability of the technique to study photosensitive materials. (C) 2010 Optical Society of America491834993505Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fotonica para Comunicacoes Opticas (FOTONICOM)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Non-Standard Structure Formation Scenarios

Observations on galactic scales seem to be in contradiction with recent high resolution N-body simulations. This so-called cold dark matter (CDM) crisis has been addressed in several ways, ranging from a change in fundamental physics by introducing self-interacting cold dark matter particles to a tuning of complex astrophysical processes such as global and/or local feedback. All these efforts attempt to soften density profiles and reduce the abundance of satellites in simulated galaxy halos. In this contribution we are exploring the differences between a Warm Dark Matter model and a CDM model where the power on a certain scale is reduced by introducing a narrow negative feature (''dip''). This dip is placed in a way so as to mimic the loss of power in the WDM model: both models have the same integrated power out to the scale where the power of the Dip model rises to the level of the unperturbed CDM spectrum again. Using N-body simulations we show that that the new Dip model appears to be a viable alternative to WDM while being based on different physics: where WDM requires the introduction of a new particle species the Dip stems from a non-standard inflationary period. If we are looking for an alternative to the currently challenged standard LCDM structure formation scenario, neither the LWDM nor the new Dip model can be ruled out with respect to the analysis presented in this contribution. They both make very similar predictions and the degeneracy between them can only be broken with observations yet to come.Comment: 4 pages, 3 figures; to appear in "The Evolution of Galaxies III. From Simple Approaches to Self-Consistent Models", proceedings of the 3rd EuroConference on the evolution of galaxies, held in Kiel, Germany, July 16-20, 200

Angular dependence of the bulk nucleation field Hc2 of aligned MgB2 crystallites

The angular dependence of the bulk nucleation field of a sample made of aligned MgB2 crystallites was obtained using dc magnetization and ac susceptibility measurements. A good fitting of the data by the three-dimensional anisotropic Ginzburg-Landau theory attests to the bulk nature of the critical field H-c2. We found a mass anisotropy ratio epsilon2 approximate to0.39 that implies an anisotropy of the Fermi velocity, with a ratio of 1.6 between the in-plane and perpendicular directions, if an isotropic gap energy is assumed. For an s-wave anisotropic gap this ratio could increase to 2.5. Besides the fundamental implications of this result, it also implies the use of texturization techniques to optimize the critical current in wires and other polycrystalline forms of MgB2.641

RELICS: The Reionization Lensing Cluster Survey and the Brightest High-z Galaxies

Massive foreground galaxy clusters magnify and distort the light of objects behind them, permitting a view into both the extremely distant and intrinsically faint galaxy populations. We present here the z ~ 6-8 candidate high-redshift galaxies from the Reionization Lensing Cluster Survey (RELICS), a Hubble and Spitzer Space Telescope survey of 41 massive galaxy clusters spanning an area of ≈200 arcmin². These clusters were selected to be excellent lenses, and we find similar high-redshift sample sizes and magnitude distributions as the Cluster Lensing And Supernova survey with Hubble (CLASH). We discover 257, 57, and eight candidate galaxies at z ~ 6, 7, and 8 respectively, (322 in total). The observed (lensed) magnitudes of the z ~ 6 candidates are as bright as AB mag ~23, making them among the brightest known at these redshifts, comparable with discoveries from much wider, blank-field surveys. RELICS demonstrates the efficiency of using strong gravitational lenses to produce high-redshift samples in the epoch of reionization. These brightly observed galaxies are excellent targets for follow-up study with current and future observatories, including the James Webb Space Telescope

Lattice worldline representation of correlators in a background field

We use a discrete worldline representation in order to study the continuum limit of the one-loop expectation value of dimension two and four local operators in a background field. We illustrate this technique in the case of a scalar field coupled to a non-Abelian background gauge field. The first two coefficients of the expansion in powers of the lattice spacing can be expressed as sums over random walks on a d-dimensional cubic lattice. Using combinatorial identities for the distribution of the areas of closed random walks on a lattice, these coefficients can be turned into simple integrals. Our results are valid for an anisotropic lattice, with arbitrary lattice spacings in each direction.Comment: 54 pages, 14 figure

Phenotypic redshifts with self-organizing maps: A novel method to characterize redshift distributions of source galaxies for weak lensing

Wide-field imaging surveys such as the Dark Energy Survey (DES) rely on coarse measurements of spectral energy distributions in a few filters to estimate the redshift distribution of source galaxies. In this regime, sample variance, shot noise, and selection effects limit the attainable accuracy of redshift calibration and thus of cosmological constraints. We present a new method to combine wide-field, few-filter measurements with catalogs from deep fields with additional filters and sufficiently low photometric noise to break degeneracies in photometric redshifts. The multi-band deep field is used as an intermediary between wide-field observations and accurate redshifts, greatly reducing sample variance, shot noise, and selection effects. Our implementation of the method uses self-organizing maps to group galaxies into phenotypes based on their observed fluxes, and is tested using a mock DES catalog created from N-body simulations. It yields a typical uncertainty on the mean redshift in each of five tomographic bins for an idealized simulation of the DES Year 3 weak-lensing tomographic analysis of $\sigma_{\Delta z} = 0.007$, which is a 60% improvement compared to the Year 1 analysis. Although the implementation of the method is tailored to DES, its formalism can be applied to other large photometric surveys with a similar observing strategy.Comment: 24 pages, 11 figures; matches version accepted to MNRA

The Conceptual Definition of Sarcopenia: Delphi Consensus from the Global Leadership Initiative in Sarcopenia (GLIS)

\ua9 2024 The Author(s).Importance: Sarcopenia, the age-related loss of muscle mass and strength/function, is an important clinical condition. However, no international consensus on the definition exists. Objective: The Global Leadership Initiative in Sarcopenia (GLIS) aimed to address this by establishing the global conceptual definition of sarcopenia. Design: The GLIS steering committee was formed in 2019-21 with representatives from all relevant scientific societies worldwide. During this time, the steering committee developed a set of statements on the topic and invited members from these societies to participate in a two-phase International Delphi Study. Between 2022 and 2023, participants ranked their agreement with a set of statements using an online survey tool (SurveyMonkey). Statements were categorised based on predefined thresholds: strong agreement (>80%), moderate agreement (70-80%) and low agreement (<70%). Statements with strong agreement were accepted, statements with low agreement were rejected and those with moderate agreement were reintroduced until consensus was reached. Results: 107 participants (mean age: 54 \ub1 12 years [1 missing age], 64% men) from 29 countries across 7 continents/regions completed the Delphi survey. Twenty statements were found to have a strong agreement. These included; 6 statements on \u27general aspects of sarcopenia\u27 (strongest agreement: the prevalence of sarcopenia increases with age (98.3%)), 3 statements on \u27components of sarcopenia\u27 (muscle mass (89.4%), muscle strength (93.1%) and muscle-specific strength (80.8%) should all be a part of the conceptual definition of sarcopenia)) and 11 statements on \u27outcomes of sarcopenia\u27 (strongest agreement: sarcopenia increases the risk of impaired physical performance (97.9%)). A key finding of the Delphi survey was that muscle mass, muscle strength and muscle-specific strength were all accepted as \u27components of sarcopenia\u27, whereas impaired physical performance was accepted as an \u27outcome\u27 rather than a \u27component\u27 of sarcopenia. Conclusion and relevance: The GLIS has created the first global conceptual definition of sarcopenia, which will now serve to develop an operational definition for clinical and research settings

Mortality from HIV-associated meningitis in sub-Saharan Africa: a systematic review and meta-analysis.

INTRODUCTION: HIV-associated cryptococcal, TB and pneumococcal meningitis are the leading causes of adult meningitis in sub-Saharan Africa (SSA). We performed a systematic review and meta-analysis with the primary aim of estimating mortality from major causes of adult meningitis in routine care settings, and to contrast this with outcomes from clinical trial settings. METHODS: We searched PubMed, EMBASE and the Cochrane Library for published clinical trials (defined as randomized-controlled trials (RCTs) or investigator-managed prospective cohorts) and observational studies that evaluated outcomes of adult meningitis in SSA from 1 January 1990 through 15 September 2019. We performed random effects modelling to estimate pooled mortality, both in clinical trial and routine care settings. Outcomes were stratified as short-term (in-hospital or two weeks), medium-term (up to 10 weeks) and long-term (up to six months). RESULTS AND DISCUSSION: Seventy-nine studies met inclusion criteria. In routine care settings, pooled short-term mortality from cryptococcal meningitis was 44% (95% confidence interval (95% CI):39% to 49%, 40 studies), which did not differ between amphotericin (either alone or with fluconazole) and fluconazole-based induction regimens, and was twofold higher than pooled mortality in clinical trials using amphotericin based treatment (21% (95% CI:17% to 25%), 17 studies). Pooled short-term mortality of TB meningitis was 46% (95% CI: 33% to 59%, 11 studies, all routine care). For pneumococcal meningitis, pooled short-term mortality was 54% in routine care settings (95% CI:44% to 64%, nine studies), with similar mortality reported in two included randomized-controlled trials. Few studies evaluated long-term outcomes. CONCLUSIONS: Mortality rates from HIV-associated meningitis in SSA are very high under routine care conditions. Better strategies are needed to reduce mortality from HIV-associated meningitis in the region

The Role of Medical Language in Changing Public Perceptions of Illness

This study was designed to investigate the impact of medical terminology on perceptions of disease. Specifically, we look at the changing public perceptions of newly medicalized disorders with accompanying newly medicalized terms (e.g. impotence has become erectile dysfunction disorder). Does using “medicalese” to label a recently medicalized disorder lead to a change in the perception of that condition? Undergraduate students (n = 52) rated either the medical or lay label for recently medicalized disorders (such as erectile dysfunction disorder vs. impotence) and established medical conditions (such as a myocardial infarction vs. heart attack) for their perceived seriousness, disease representativeness and prevalence. Students considered the medical label of the recently medicalized disease to be more serious (mean = 4.95 (SE = .27) vs. mean = 3.77 (SE = .24) on a ten point scale), more representative of a disease (mean = 2.47 (SE = .09) vs. mean = 1.83 (SE = .09) on a four point scale), and have lower prevalence (mean = 68 (SE = 12.6) vs. mean = 122 (SE = 18.1) out of 1,000) than the same disease described using common language. A similar pattern was not seen in the established medical conditions, even when controlled for severity. This study demonstrates that the use of medical language in communication can induce bias in perception; a simple switch in terminology results in a disease being perceived as more serious, more likely to be a disease, and more likely to be a rare condition. These findings regarding the conceptualization of disease have implications for many areas, including medical communication with the public, advertising, and public policy