Small-scale Intensity Mapping: Extended Halos as a Probe of the Ionizing Escape Fraction and Faint Galaxy Populations during Reionization

We present a new method to quantify the value of the escape fraction of ionizing photons, and the existence of ultra-faint galaxies clustered around brighter objects during the epoch of cosmic reionization, using the diffuse Ly$\alpha$, continuum and H$\alpha$ emission observed around galaxies at $z\sim6$. We model the surface brightness profiles of the diffuse halos considering the fluorescent emission powered by ionizing photons escaping from the central galaxies, and the nebular emission from satellite star-forming sources, by extending the formalisms developed in Mas-Ribas & Dijkstra (2016) and Mas-Ribas et al. (2017). The comparison between our predicted profiles and Ly$\alpha$ observations at $z=5.7$ and $z=6.6$ favors a low ionizing escape fraction, $f_{\rm esc}^{\rm ion}\sim5\%$, for galaxies in the range $-19\gtrsim M_{\rm UV} \gtrsim -21.5$. However, uncertainties and possible systematics in the observations do not allow for firm conclusions. We predict H$\alpha$ and rest-frame visible continuum observations with JWST, and show that JWST will be able to detect extended (a few tens of kpc) fluorescent H$\alpha$ emission powered by ionizing photons escaping from a bright, $L\gtrsim 5L^*$, galaxy. Such observations can differentiate fluorescent emission from nebular emission by satellite sources. We discuss how observations and stacking of several objects may provide unique constraints on the escape fraction for faint galaxies and/or the abundance of ultra-faint radiation sources.Comment: 9 pages, 4 figures, re-submitted after referee report to Ap

Glycosidic bond specificity of glucansucrases:on the role of acceptor substrate binding residues

Many lactic acid bacteria produce extracellular alpha-glucan polysaccharides using a glucansucrase and sucrose as glucose donor. The structure and the physicochemical properties of the alpha-glucans produced are determined by the nature of the glucansucrase. Typically, the alpha-glucans contain two types of alpha-glycosidic linkages, for example, (alpha 1-2), (alpha 1-3), (alpha 1-4) or (alpha 1-6), which may be randomly or regularly distributed. Usually, the alpha-glucan chains are also branched, which gives rise to an additional level of complexity. Even though the first crystal structure was reported in 2010, our current understanding of the structure-function relationships of glucansucrases is not advanced enough to predict the alpha-glucan specificity from the sequence alone. Nevertheless, based on sequence alignments and site-directed mutagenesis, a few amino acid residues have been identified as being important for the glycosidic bond specificity of glucansucrases. A new development in GH70 research was the identification of a cluster of alpha-glucan disproportionating enzymes. Here, we discuss the current insights into the structure-function relationships of GH70 enzymes in the light of the recently determined crystal structure of glucansucrases

Moored observations of turbulent mixing events in deep Lake Garda (I)

Deep water circulation and mixing processes in deep lakes are largely unknown, although they are responsible for the transport of matter, nutrients and pollutants. Such a lack of knowledge cannot be reliably provided by numerical hydrodynamic modelling studies because detailed observations are typically not available to validate them. To overcome some of these deficiencies, a dedicated yearlong mooring comprising 100 high-resolution temperature sensors and a single current meter were located in the deeper half of the 344 m deepest point of the subalpine Lake Garda (Italy). The observations show peaks and calms of turbulent exchange, besides ubiquitous internal wave activity. In late winter, northerly winds activate episodic deep convective overturning, the dense water being subsequently advected along the lake-floor. Besides deep convection, such winds also set-up seiches and inertial waves that are associated with about 100 times larger turbulence dissipation rates than that by semidiurnal internal wave breaking observed in summer. In the lower 60 m above the lake-floor however, the average turbulence dissipation rate is approximately constant in value year-around, being about 10 times larger than open-ocean values, except during deep convection episodes.Comment: 42 pages, 10 figure

Huygens STED Deconvolution Increases Signal-to-Noise and Image Resolution towards 22 nm

Image restoration aims to make optimal use of the data provided by the light microscope to recover the object being imaged; in other words, to "figure out what the microscope is actually trying to tell us.” To achieve this, the distortions introduced by the imaging process need to be undone insofar possibl

Convection under internal waves in an alpine lake

Turbulent mixing processes in deep alpine Lake Garda (I) have not extensively been observed. Knowledge about drivers of turbulent fluxes are important for insights in the transport of matter, nutrients and pollutants, in the lake and in natural water bodies in general. In this paper, the occurrence of internal wave induced turbulent convection, termed 'internally forced convection', is addressed as opposed to the more common shear-induced turbulence in a density stratified environment. Observations are analyzed from a dedicated yearlong mooring holding 100 high-resolution temperature sensors at 1.5 m intervals under a single current meter in the deeper half of the 344 m deep lake-center. Episodically, the weakly density stratified waters in the lower 50 m above the lake-floor show spectral slope and coherence evidence of short-term (15–30 min) convective motions under internal waves that are supported by the stronger stratified waters above. The near-homogeneous conditions are not attributable to frictional Ekman dynamics, but to large-scale internal wave crests

Interleukin (IL)-1 gene polymorphisms: relevance of disease severity associated alleles with IL-1beta and IL-1ra production in multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is an autoimmune disorder, with a considerable genetic influence on susceptibility and disease course. Cytokines play an important role in MS pathophysiology, and genes encoding various cytokines are logical candidates to assess possible associations with MS susceptibility and disease course. We previously reported an association of a combination of polymorphisms in the interleukin (IL)-1B and IL-1 receptor antagonist (IL-1RN) genes (i.e. IL-1RN allele 2+/IL-1B(+3959)allele 2-) with disease severity in MS. Extending this observation, we investigated whether IL-1beta and IL-1ra production differed depending on carriership of this gene combination. METHODS: Twenty MS patients and 20 controls were selected based upon carriership of the specific combination. In whole blood, in vitro IL-1beta and IL-1ra production was determined by enzyme-linked immunosorbent-assay after 6 and 24 h of stimulation with lipopolysaccharide. RESULTS: Carriers of the specific combination produced more IL-1ra, especially in MS patients, although not significantly. IL-1ra production was significantly higher in individuals homozygous for IL-1RN allele 2. In patients, Il-1ra production was higher and IL-1beta production lower compared with controls. In primary progressive patients, the IL-1beta /IL-1ra ratio was significantly lower than in relapsing-remitting patients. CONCLUSION: Our results suggest higher in vitro IL-1ra production in carriers of IL-1RN allele 2, with an indication of an allelic dose-effect relationship

Внутренние источники финансирования инвестиционной деятельности в Украине

В статье рассмотрены 4 основных источника финансирования инвестиционной деятельности, и проблемы связанные с их формированием и использованием. Учитывая непосредственное влияние внутренних источников инвестиций на экономический рост, и их минимальное использование в Украине, тема становится актуальной, требующей детальной проработки.У статті розглянуті 4 основні джерела фінансування інвестиційної діяльності та проблеми, пов'язані з їх формуванням та використанням. З огляду на безпосередній вплив внутрішніх джерел інвестицій на економічний зріст, та їх мінімальне використання в Україні, тема стає актуальною, потребуючою детального опрацювання.Four basic sources of financing investment activity as well as problems related to their forming and use are considered in the article. This theme is essential and needs detailed development under circumstances of direct impact of the internal sources of investment on economical growth and still minimum use in Ukraine