Effect of bevelled silo outlet in the flow rate during discharge

We investigate the effect of a bevelled (or slanted) outlet on the discharge rate of mono-sized spheres from a quasi-two-dimensional silo, using the discrete element method. In contrast to hopper discharges, where the bevelling is across the entire base of the container, we study a bevelled opening that is significantly smaller than the silo width and in which the slanting is limited to half a sphere diameter at the boundary of the outlet. We show that the bevelling increases the flow rate comparably to the inclination in hopper walls. Using Beverloo's model, we relate this increase in rate to what we define as the ‘effective opening’ of the silo and analyse the velocity profiles associated with the discharges. We show that different openings, having effectively the same discharge rates, give rise to distinctly different internal dynamics in the silo. These results have the potential to aid industrial processes by fine-tuning and improving control of silo discharges, with a minimal impact on silo design, thus significantly reducing production and handling costs.Fil: Gago, Paula Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Imperial College London; Reino UnidoFil: Madrid, Marcos Andres. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Boettcher, Stefan. University of Emory; Estados UnidosFil: Blumenfeld, Raphael. Imperial College London; Reino UnidoFil: King, Peter. Imperial College London; Reino Unid

A cartography of dispossession: assessing spatial reorganization in state-led conservation in Saadani, Tanzania

Proclaimed as the "most important conservation success story", protected areas have become the preferred method among state signatories to the Convention on Biological Diversity for addressing conservation challenges. However, state-governed protected areas have been criticized for their failure to achieve ecological and social goals. Reaching a consensus on wildlife conservation strategies has not translated into widespread acceptance of state-governed protected areas by local communities. Critics debate whether the state is sincere and efficient when exerting spatial control. This article analyses state-based conservation in the Saadani landscape in Tanzania, exploring the nature of spatial reorganization and institutional approaches guiding the establishment of protected areas. Spatial reorganization and the actions of conservation organizations have led to the disenfranchisement of the very people whose efforts had enabled biodiversity to be conserved. This is despite an apparent shift in the nature of Tanzania's conservation policies towards more participatory approaches. Through detailing mechanisms used by the state for exerting spatial control in Saadani, we highlight how the approach has been counterproductive for satisfying the country's commitment to the Aichi framework on biodiversity targets and has undermined grassroots backing for conservation. In the context of strong support from the international conservation organizations for Tanzania's conservation efforts, this suggests the need for reassessing global conservation policies and identifying urgent measures and effective mechanisms to protect rights to territory and ancestral tenure in places targeted for conservation. Keywords: conservation, Convention on Biological Diversity, protected areas, spatial reorganization, actions of the state, Saadani, TANAPA, Tanzania. Uvinj

Relative Frequencies of Blue Stragglers in Galactic Globular Clusters: Constraints for the Formation Mechanisms

We discuss the main properties of the Galactic globular cluster (GC) blue straggler stars (BSS), as inferred from our new catalog containing nearly 3000 BSS. The catalog has been extracted from the photometrically homogeneous V vs. (B-V) color-magnitude diagrams (CMD) of 56 GCs, based on WFPC2 images of their central cores. In our analysis we used consistent relative distances based on the same photometry and calibration. The number of BSS has been normalized to obtain relative frequencies (F_{BSS}) and specific densities (N_S) using different stellar populations extracted from the CMD. The cluster F_{BSS} is significantly smaller than the relative frequency of field BSS. We find a significant anti-correlation between the BSS relative frequency in a cluster and its total absolute luminosity (mass). There is no statistically significant trend between the BSS frequency and the expected collision rate. F_{BSS} does not depend on other cluster parameters, apart from a mild dependence on the central density. PCC clusters act like normal clusters as far as the BSS frequency is concerned. We also show that the BSS luminosity function for the most luminous clusters is significantly different, with a brighter peak and extending to brighter luminosities than in the less luminous clusters. These results imply that the efficiency of BSS production mechanisms and their relative importance vary with the cluster mass.Comment: 12 pages, 3 figures. accepted for publication in ApJ

Caracterización de las diferentes modalidades de maltrato infantil y su frecuencia registrados en el hospital de Vista Hermosa en la localidad de Ciudad Bolívar, Bogotá, D.C.

76 Páginas.En Ciudad Bolívar, Bogotá existe una proporción de niños víctimas de violencia. Se realizó un diagnóstico actual de la situación de maltrato en esta localidad para seguimiento a dicha problemática; estableciendo la frecuencia de las diferentes modalidades de maltrato infantil en niños menores de 18 años, en Enero a Diciembre del 2010, a través de un estudio descriptivo observacional de corte transversal. Se analizaron 1789 fichas de maltrato infantil, 689 correspondieron a la primera notificación de cada victima, no se encontró relación entre edad de la primera notificación y número de maltratos. En 100% de los casos se encontró maltrato emocional, maltrato físico en 172 personas ( 81.9%) y maltrato sexual en 164 personas ( 89.1%) . Existe un problema de maltrato infantil en esta localidad, por ser un problema que atañe a la Pediatría debe ser objeto de programas de prevención

The contribution of sulfate ions and protons to the specific capacitance of microporous carbon monoliths

The monoliths studied in this work show large specific surface areas (up to 1600 m2 g-1), high densities (up to 1.17 g cm -3) and high electrical conductivities (up to 9.5 S cm-1). They are microporous carbons with pore sizes up to 1.3 nm but most of them below 0.75 nm. They also show oxygen functionalities. The electrochemical behavior of the monoliths is studied in three-electrode cells with aqueous H2SO4 solution as electrolyte. This work deals with the contribution of the sulfate ions and protons to the specific capacitance of carbon monoliths having different surface areas and different contents of oxygen groups. Protons contribute with a pseudocapacitance (up to 152 F g -1) in addition to the double layer capacitance. Sulfate ions contribute with a double layer capacitance only. At the double layer, the capacitance of the sulfate ions (up to 291 F g-1) is slightly higher than that of protons (up to 251 F g-1); both capacitances increase as the surface area increases. The preference of protons to be electroadsorbed at the double layer and the broader voltage window of these ions account for their higher contribution (70%) to the double layer capacitance. © 2014 Elsevier B.V. All rights reserved.Financial support through the projects MAT2011-25198, MP 1004 and PROMETEO/2009/047 is gratefully acknowledged. V.B. thanks MINECO for R&C contract.Peer Reviewe

The contribution of sulfate ions and protons to the specific capacitance of microporous carbon monoliths

The monoliths studied in this work show large specific surface areas (up to 1600 m2 g-1), high densities (up to 1.17 g cm-3) and high electrical conductivities (up to 9.5 S cm-1). They are microporous carbons with pore sizes up to 1.3 nm but most of them below 0.75 nm. They also show oxygen functionalities. The electrochemical behavior of the monoliths is studied in three-electrode cells with aqueous H2SO4 solution as electrolyte. This work deals with the contribution of the sulfate ions and protons to the specific capacitance of carbon monoliths having different surface areas and different contents of oxygen groups. Protons contribute with a pseudocapacitance (up to 152 F g-1) in addition to the double layer capacitance. Sulfate ions contribute with a double layer capacitance only. At the double layer, the capacitance of the sulfate ions (up to 291 F g-1) is slightly higher than that of protons (up to 251 F g-1); both capacitances increase as the surface area increases. The preference of protons to be electroadsorbed at the double layer and the broader voltage window of these ions account for their higher contribution (70 %) to the double layer capacitance.Financial support through the projects MAT2011-25198, MP 1004 and PROMETEO/2009/047 is gratefully acknowledged. V.B. thanks MINECO for R&C contract

LET’s CONNECT community mentorship program for youths with peer social problems: Preliminary findings from a randomized effectiveness trial

This study examined the effectiveness of LET’s CONNECT (LC), a community mentorship program for youths who report peer social problems, which is based on a positive youth development framework. Participants were 218 youths (66.5% girls), aged 12 to 15 years, who were recruited from an urban medical emergency department and screened positive for bullying victimization, bullying perpetration, and/or low social connectedness. Youths were randomized to LC (n = 106) or the control condition (n = 112). Six‐month outcomes were assessed with self‐report measures of youth social connectedness, community connectedness, thwarted belongingness, depression, self‐esteem, and suicidal ideation. LC was associated with a significant increase in only one of these outcomes, social connectedness (effect size = 0.4). It was associated consistently with trend‐level positive changes for thwarted belongingness (decreased), depression (decreased), community connectedness, and self‐esteem (effect sizes = 0.2). There was no effect on suicidal ideation (effect size = 0.0), and although not a primary outcome, eight youths in the LC condition and seven youths in the control condition engaged in suicidal behavior between baseline and follow‐up. Although LC effect sizes are consistent with those from previous studies of community mentorship, there were multiple challenges to LC implementation that affected dosage and intervention fidelity, and that may account for the lack of stronger positive effects.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145529/1/jcop21979.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145529/2/jcop21979_am.pd

Rapid evolution of a novel protective symbiont into keystone taxon in Caenorhabditis elegans microbiota

Protective microbes have a major role in shaping host–pathogen interactions, but their relative importance in the structure of the host microbiota remains unclear. Here, we used a network approach to characterize the impact of a novel, experimentally evolved ‘protective microbial symbiont’ (Enterococcus faecalis) on the structure and predicted function of the natural microbiota of the model organism Caenorhabditis elegans. We used microbial network analysis to identify keystone taxa and describe the hierarchical placement of protective and non-protective symbionts in the microbiota. We found that early colonization with symbionts produce statistically significant changes in the structure of the community. Notably, only the protective E. faecalis became a keystone taxon in the nematode microbiota. Non-protective lineages of the same bacterial species remained comparatively unimportant to the community. Prediction of functional profiles in bacterial communities using PICRUSt2 showed that the presence of highly protective E. faecalis decreased the abundance of ergothioneine (EGT) biosynthesis pathway involved in the synthesis of the antioxidant molecule EGT, a potential public good. These data show that in addition to direct antagonism with virulent pathogens, keystone protective symbionts are linked to modified bacterial community structure and possible reductions in public goods, potentially driving decreased antioxidant defense. We suggest that this response could suppress infection via wholesale microbial community changes to further benefit the host. These findings extend the concept of protective symbionts beyond bodyguards to ecosystem engineers

RRS James Cook Cruise JC159 28 February - 11 April 2018. Hydrographic sections from the Brazil to the Benguela Current across 24S in the Atlantic

A Hydrographic section was occupied at a nominal latitude of 24°S in the Atlantic Ocean during March and April 2018 on Cruise JC159 of RRS James Cook. The primary objective of this cruise was to measure ocean physical, chemical and biological parameters in order to establish regional budgets of heat, freshwater and carbon, and to infer decadal variability. In addition, 371 Niskin Bottles were sampled for microplastics, reflecting increasing awareness of plastics pollution in the oceans. A total of 121 CTD/LADCP stations were conducted, including one test station and two CFC bottle blank stations. In addition to temperature, salinity and oxygen profiles from the sensors on the CTD package, water samples from a 24 x 20 litre rosette were analysed for the following parameters at all stations: salinity; dissolved oxygen; inorganic nutrients; alkalinity and dissolved inorganic carbon; CFCs. Samples were collected for shore analysis for oxygen and carbon isotopes (del-18O, del13C and del-14C). Samples were collected and filtered for pigments (shore analysis) at 44 stations and for microplastics at 45 stations. 8 Argo floats were deployed, including two Bio-PROVOR floats and 2 Deep ARVORs. In addition, samples were collected from the ships’ underway system to calibrate and compliment the data continually collected by the TSG (thermosalinograph). Full depth velocity measurements were made at every station by LADCP (Lowered Acoustic Doppler Current Profiler) mounted on the frame of the rosette. Throughout the cruise, velocity data in the upper few hundred metres of the water column were collected by the ship’s VMADCP (Vessel Mounted Acoustic Doppler Current Profiler) transducers (75Hz and 150Hz) mounted on one of the two drop keels. Meteorological variables were monitored using the onboard surface water and meteorological sampling system (SURFMET). Bathymetric data were collected using the Kongsberg EM122 multibeam system and the EA640 echo sounder. This report describes the methods used to acquire and process the data on board the ship during cruise JC159

The Mtr4 Ratchet Helix and Arch Domain both Function to Promote RNA Unwinding

Mtr4 is a conserved Ski2-like RNA helicase and a subunit of the TRAMP complex that activates exosomemiated 3-5 turnover in nuclear RNA surveillance and processing pathways. Prominent features of the Mtr4 structure include a four-domain ring-like helicase core and a large arch domain that spans the core. The ‘ratchet helix’ is positioned to interact with RNA substrates as they move through the helicase. However, the contribution of the ratchet helix in Mtr4 activity is poorly understood. Here we show that strict conservation along the ratchet helix is particularly extensive for Ski2-like RNA helicases compared to related helicases. Mutation of residues along the ratchet helix alters in vitro activity in Mtr4 and TRAMP and causes slow growth phenotypes in vivo. We also identify a residue on the ratchet helix that influences Mtr4 affinity for polyadenylated substrates. Previous work indicated that deletion of the arch domain has minimal effect on Mtr4 unwinding activity. We now show that combining the arch deletion with ratchet helix mutations abolishes helicase activity and produces a lethal in vivo phenotype. These studies demonstrate that the ratchet helix modulates helicase activity and suggest that the arch domain plays a previously unrecognized role in unwinding substrates