1,568 research outputs found
Engaging Disconnected Young People in Education and Work
Project Rise served 18- to 24-year-olds who lacked a high school diploma or the equivalent and had been out of school, out of work, and not in any type of education or training program for at least six months. After enrolling as part of a group (or cohort) of 25 to 30 young people, Project Rise participants were to engage in a 12-month sequence of activities centered on case management, classroom education focused mostly on preparation for a high school equivalency certificate, and a paid part-time internship that was conditional on adequate attendance in the educational component. After the internship, participants were expected to enter unsubsidized employment, postsecondary education, or both. The program was operated by three organizations in New York City; one in Newark, New Jersey; and one in Kansas City, Missouri
Strong contribution of diatom resting spores to deep-sea carbon transfer in naturally iron-fertilized waters downstream of South Georgia
Biogeochemical and diatom export fluxes are presented from two bathypelagic sediment trap deployments in the Antarctic Zone of the Southern Ocean. One of the sediment traps was deployed in very productive, naturally iron-fertilized waters downstream of South Georgia (P3, 2000 m) and compared to a deployment in moderately productive waters upstream of the island system (P2, 1500 m). At both sites significant diatom export events occurred in spring (November) and contained mostly empty cells that were associated with low particulate organic carbon (POC) fluxes. A summer export pulse occurred one month later at P2 (end February/March) compared to P3 (end January). Diatom fluxes at P3 were one order of magnitude higher than at P2, a difference mainly attributed to the short and intense export of resting spores from Chaetoceros Hyalochaete and Thalassiosira antarctica species. Aside from these resting spores, diatom export assemblages at both sites were dominated by empty Fragilariopsis kerguelensis frustules. The fraction of diatoms exported as empty frustules was considerably lower at P3 (52%) than P2 (91%). This difference was related to the flux of intact diatom resting spores at P3 and may partially explain the lower Si:C export stoichiometry observed at P3 (1.1) compared to P2 (1.5). Through the enumeration of full diatom frustules and subsequent biomass calculations we estimate that diatom resting spores account for 42% of annual POC flux in the productive waters downstream of South Georgia. At both sites the contribution of diatom vegetative stages to POC fluxes was considerably lower (<5%). From these analyses we conclude that resting spore export contributes towards the slightly higher bathypelagic (POC) flux at P3 (40.6 mmol m−2 y−1) compared to P2 (26.4 mmol m−2 y−1). We compared our sediment trap records with previously published diatom assemblage data from the mixed layer and surface sediments (3760 m) around South Georgia. The relative proportion of diatom resting spores within diatom assemblages increases as a function of depth and is explained by selective preservation of their robust frustules. Our study highlights the significance of diatom resting spore export as a carbon vector out of the mixed layer. Furthermore, the contribution or resting spores to POC flux in the bathypelagic ocean and sediments suggests they play a particularly important role in sequestering biologically fixed CO2 over climatically relevant timescales
Impact and costs of proposed scenarios for power sector decarbonisation: An Italian case study
In the face of ever more ambitious global energy challenges, the European Union has set striving climate targets for 2030, planning to increase renewable energy penetration in the electricity generation as a key measure towards a clean energy transition. To respond to the challenge of keeping the increase in power sector costs, that inevitably arises when a profound reconfiguration of the electricity generation sector is expected, to the lowest possible, this paper aims to quantify the economic burden associated with the reduction of direct CO2 emissions through a comparative assessment of various alternatives proposed for 2030 ranked in terms of their cost-effectiveness. A sensitivity analysis is also applied to the main economic and energy parameters that make up CO2 mitigation costs to include those uncertainties that characterise future projections. The impact of electricity generation shares on CO2 mitigation costs is assessed thus providing a basis for the definition of alternative configurations for the Italian electricity sector capable to achieve the desired environmental performance with a limited economic impact. Finally, results reveal that those scenarios based largely on natural gas and solar source are characterized by high mitigation costs, while energy efficiency is essential for a virtuous and clean electricity sector along with the use of all available sources in appropriate shares, both renewable and non-renewable, to pursue the highest environmental objectives in a cost-effective manner. Although related to the Italian case, the methodology provided in this study can be applied to any other electricity sector to ultimately evaluate the economic burden arising from possible different configurations
Impact of displacement demand reliability for seismic vulnerability assessment at an urban scale
This paper addresses seismic vulnerability assessment at an urban scale by focusing on the displacement demand determination for building damage prediction. The study is based on the comparison of urban seismic damage distributions obtained by the displacement demand computed using non-linear time-history analysis (NLTHA) with three simplified methods. These methods include the N2 method, the Lin & Miranda proposal and an optimized version of the N2 method. Comparing the different damage distributions from the three simplified methods with the one obtained by time-history analysis helps understanding the reliability of displacement demand determination. The study is carried out on Sion and Martigny, two typical Swiss cities. For the case of Sion, results clearly show that using N2 method may lead to significant overestimation of damage grade distribution. The use of Lin & Miranda method and optimized version of N2 improves the damage prediction in both cases. For the other studied case of Martigny, N2 method and Lin & Miranda proposal are not accurate. The optimized version of N2 method provides stable and reliable results
Nanoplastics affect moulting and faecal pellet sinking in Antarctic krill (Euphausia superba) juveniles
Plastic debris has been identified as a potential threat to Antarctic marine ecosystems, however, the impact of nanoplastics (<1 μm) is currently unexplored. Antarctic krill (Euphausia superba) is a keystone species of Southern Ocean pelagic ecosystems, which plays a central role in the Antarctic food webs and carbon (C) cycle. Krill has been shown to rapidly fragment microplastic beads through the digestive system, releasing nanoplastics with unknown toxicological effects. Here we exposed krill juveniles to carboxylic (COOH, anionic) and amino- (NH2, cationic) polystyrene nanoparticles (PS NPs) and we investigated lethal and sub-lethal endpoints after 48 h. The analysis of PS NP suspensions in Antarctic sea water (SW) media showed that PS-COOH formed large agglomerates (1043 ± 121 nm), while PS-NH2 kept their nominal size (56.8 ± 3 nm) during the exposure time. After 48 h, no mortality was found but increase in exuviae production (12.6 ± 1.3%) and reduced swimming activity were observed in juveniles exposed to PS-NH2. The microbial community composition in SW supports the release of krill moults upon PS NP exposure and stimulates further research on the pivotal role of krill in shaping Southern Ocean bacterial assemblages. The presence of fluorescent signal in krill faecal pellets (FPs) confirmed the waterborne ingestion and egestion of PS-COOH at 48 h of exposure. Changes in FP structure and properties were also associated to the incorporation of PS NPs regardless of their surface charge. The effects of PS NPs on krill FP properties were compared to Control 0 h as a reference for full FPs (plastic vs food) and Control 48 h as a reference for more empty-like FPs (plastic vs lack of food). Exposure to PS NPs led to a FP sinking rate comparable to Control 48 h, but significantly lower than Control 0 h (58.40 ± 23.60 m/d and 51.23 ± 28.60 m/d for PS-COOH and PS-NH2; 168.80 ± 74.58 m/d for Control 0 h). Considering the important role played by krill in the food web and C export in the Southern Ocean, the present study provides cues about the potential impact of nanoplastics on Antarctic pelagic ecosystems and their biogeochemical cycles
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Ganglion-specific splicing of TRPV1 underlies infrared sensation in vampire bats.
Vampire bats (Desmodus rotundus) are obligate blood feeders that have evolved specialized systems to suit their sanguinary lifestyle. Chief among such adaptations is the ability to detect infrared radiation as a means of locating hotspots on warm-blooded prey. Among vertebrates, only vampire bats, boas, pythons and pit vipers are capable of detecting infrared radiation. In each case, infrared signals are detected by trigeminal nerve fibres that innervate specialized pit organs on the animal's face. Thus, vampire bats and snakes have taken thermosensation to the extreme by developing specialized systems for detecting infrared radiation. As such, these creatures provide a window into the molecular and genetic mechanisms underlying evolutionary tuning of thermoreceptors in a species-specific or cell-type-specific manner. Previously, we have shown that snakes co-opt a non-heat-sensitive channel, vertebrate TRPA1 (transient receptor potential cation channel A1), to produce an infrared detector. Here we show that vampire bats tune a channel that is already heat-sensitive, TRPV1, by lowering its thermal activation threshold to about 30 °C. This is achieved through alternative splicing of TRPV1 transcripts to produce a channel with a truncated carboxy-terminal cytoplasmic domain. These splicing events occur exclusively in trigeminal ganglia, and not in dorsal root ganglia, thereby maintaining a role for TRPV1 as a detector of noxious heat in somatic afferents. This reflects a unique organization of the bat Trpv1 gene that we show to be characteristic of Laurasiatheria mammals (cows, dogs and moles), supporting a close phylogenetic relationship with bats. These findings reveal a novel molecular mechanism for physiological tuning of thermosensory nerve fibres
Early oral-motor interventions for pediatric feeding problems: What, when and how
Children with developmental delays often have feeding difficulties resulting from oral-motor problems. Based on both clinical experience and a review of published studies, oral-motor interventions have been shown to be effective in improving the oral function of preterm infants and children with neuromotor disorders, such as cerebral palsy. However, oral-motor problems may be under identified in other populations of children with developmental difficulties. The purpose of this paper is to provide a conceptual framework for understanding oral-motor skill development and problems that can occur in any infant and young child and to review oral-motor treatment techniques and their empirical support
Electrostatics promotes molecular crowding and selects the aggregation pathway in fibril-forming protein solutions
The role of intermolecular interaction in fibril-forming protein solutions and its relation with molecular conformation are crucial aspects for the control and inhibition of amyloid structures. Here, we study the fibril formation and the protein-protein interactions for two proteins at acidic pH, lysozyme and α-chymotrypsinogen. By using light scattering experiments and the Kirkwood-Buff
integral approach, we show how concentration fluctuations are damped even at moderate protein concentrations by the dominant long-ranged electrostatic repulsion, which determines an effective crowded environment. In denaturing conditions, electrostatic repulsion keeps the monomeric solution in a thermodynamically metastable state, which is escaped through kinetically populated conformational sub-states. This explains how electrostatics acts as a gatekeeper in selecting a specific aggregation pathway
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