bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence of Plasmonic Coupling in Gallium Nanoparticles/Graphene/SiC
Authors: Yi Congwen , Kim Tong‐Ho , Jiao Wenyuan , Yang Yang , Lazarides Anne , Hingerl Kurt , Bruno Giovanni , Brown April , Losurdo Maria 
Published: June 2012

AbstractGraphene is emerging as a promising material for plasmonics applications due to its strong light–matter interactions, most of which are theoretically predicted but not yet experimentally realized. Therefore, the integration of plasmonic nanoparticles to create metal nanoparticle/graphene composites enables numerous phenomena important for a range of applications from photonics to catalysis. For these applications it is important to articulate the coupling of photon‐based excitations such as the interaction between plasmons in each of the material components, as well as their charge‐based interactions dependent upon the energy alignment at the metal/graphene interface. These coupled phenomena underpin an active application area in graphene‐based composites due to nanoparticle‐dependent surface‐enhanced Raman scattering (SERS) of graphene phonon modes. This study reveals the coupling of a graphene/SiC support with Ga‐nanoparticle‐localized surface plasmon resonance, which is of particular interest due to its ability to be tuned across the UV into the near‐IR region. This work is the first demonstration of the evolving plasmon resonance on graphene during the synthesis of surface‐supported metal nanoparticles, thus providing evidence for the theoretically predicted screening revealed by a damped resonance with little energy shift. Therefore, the role of the graphene/substrate heterojunction in tailoring the plasmon resonance for nanoplasmonic applications is shown. Additionally, the coupled phenomena between the graphene–Ga plasmon properties, charge transfer, and SERS of graphene vibrational modes are explored.
Options for increasing biomass output from long‐rotation forestry
Authors: Egnell Gustaf , Björheden Rolf 
Published: June 2012

Forests managed by long‐rotation forestry already play an important role as a source for renewable biomass and energy. The biomass output from these forests may be increased through higher harvest levels, but to be sustainable over time, harvest levels cannot exceed forest growth. A large proportion of the tree biomass (tops, foliage, branches, stumps, and small and unmerchantable trees) is left on the logging site in conventional stemwood harvest, representing a considerable amount of available biomass. The realizable biomass potential is lower, due to environmental and techno‐economic constraints. If more technically adapted, efficient, and environmentally friendly biomass harvest and transport systems are developed, the realized biomass potential can be considerably increased. By complementing current stemwood harvesting technologies with systems that include logging residues, stumps, and small trees, a larger proportion of the potential will be available. In a longer term, increased forest growth can raise the biomass output. Many silvicultural treatments are available, including improved site preparation, vegetation control, insect control, browser control, genetically improved seedlings, fast growing tree species, fertilization, irrigation, denser stands, and so on. Inexpensive silvicultural measures that can be applied on large areas at a fast rate, such as using genetically improved seedling stock, have the highest potential to increase total forest production. Because of the long‐rotation periods, it will take decades to make a difference in forest production and thereby in the biomass output potential. In addition, a more efficient use of biomass in both forest and energy industries and in biorefineries of the future holds potential. © 2012 John Wiley & Sons, Ltd.This article is categorized under:

Bioenergy > Science and Materials
Bioenergy > Economics and Policy
Bioenergy > Systems and Infrastructure
Daily energy expenditure in precocial shorebird chicks: smaller species perform at higher levels
Authors: Krijgsveld Karen L. , Ricklefs Robert E. , Visser G. Henk 
Published: June 2012

AbstractWe measured daily energy expenditure (DEE) during the development periods of precocial chicks of five species of Arctic shorebirds spanning a broad range in size, in order to investigate the relationships between DEE, body size, and growth rate. We also quantified the effect of weather conditions on the energy expenditure of chicks to establish the impact of cold arctic weather on their time and energy budgets. We used the doubly labeled water method to measure DEE at ambient temperatures in an outside enclosure on the subarctic tundra at Churchill, Manitoba, Canada. Growth rate was highest in the smallest species, and in general decreased with adult size, as shown by the decrease in growth rate constant and later inflection point with increasing adult body mass. DEE ranged from 14 kJ day−1in young chicks of the smaller species to 365 kJ day−1in older chicks of the larger species. From hatching onward, DEE of shorebirds was high compared to DEE of chicks of altricial species, reflecting the high costs of locomotion and thermoregulation, and mass-specific DEE increased rapidly to adult levels. Chicks of smaller species metabolized more energy per unit mass and functioned at higher multiples of resting metabolic rate than chicks of larger species. As chicks of smaller species also had higher growth rates, and thus simultaneously invested in growth and mature function, it seems that shorebird chicks can adjust total metabolizable energy as well as its relative allocation between investment in growth and mature function. DEE was similar to cold-induced peak metabolic rates achieved by shivering thermogenesis. Because chicks were motionless during laboratory metabolism measurements, the relatively high level of DEE compared to these metabolic rates suggests that locomotion produces similar amounts of heat as shivering. Ambient temperature did not affect DEE in outdoor pens, although higher wind speed resulted in slightly increased energy expenditure. Heat produced by locomotion is possibly sufficient to sustain thermoregulation under local environments. Furthermore, when ambient temperatures are low, chicks spend more time brooding and less time foraging, which presumably counters the tendency to increase thermogenesis in response to cold.
Polygyny, Partnership Concurrency, and HIV Transmission in Sub-Saharan Africa
Authors: Reniers Georges , Tfaily Rania 
Published: June 2012

AbstractWe study the relationship between polygyny and HIV infection using nationally representative survey data with linked serostatus information from 20 African countries. Our results indicate that junior wives in polygynous unions are more likely to be HIV positive than spouses of monogamous men, but also that HIV prevalence is lower in populations with more polygyny. With these results in mind, we investigate four explanations for the contrasting individual- and ecological-level associations. These relate to (1) the adverse selection of HIV-positive women into polygynous unions, (2) the sexual network structure characteristic of polygyny, (3) the relatively low coital frequency in conjugal dyads of polygynous marriages (coital dilution), and (4) the restricted access to sexual partners for younger men in populations where polygynous men presumably monopolize the women in their community (monopolizing polygynists). We find evidence for some of these mechanisms, and together they support the proposition that polygynous marriage systems impede the spread of HIV. We relate these results to the debate about partnership concurrency as a primary behavioral driver for the fast propagation of HIV in some parts of sub-Saharan Africa.
Mortality From the Influenza Pandemic of 1918–1919: The Case of India
Authors: Chandra Siddharth , Kuljanin Goran , Wray Jennifer 
Published: June 2012

Abstract
Estimates of worldwide mortality from the influenza pandemic of 1918–1919 vary widely, from 15 million to 100 million. In terms of loss of life, India was the focal point of this profound demographic event. In this article, we calculate mortality from the influenza pandemic in India using panel data models and data from the Census of India. The new estimates suggest that for the districts included in the sample, mortality was at most 13.88 million, compared with 17.21 million when calculated using the assumptions of Davis (1951). We conclude that Davis’ influential estimate of mortality from influenza in British India is overstated by at least 24%. Future analyses of the effects of the pandemic on demographic change in India and worldwide will need to account for this significant downward revision.
In vitro differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs), derived from Wharton's jelly, into choline acetyltransferase (ChAT)‐positive cells
Authors: Zhang Lei , Tan Xuefeng , Dong Chuanming , Zou Linqing , Zhao Heyan , Zhang Xinhua , Tian Meiling , Jin Guohua 
Published: June 2012

AbstractWe isolated and expanded fibroblast‐like cells from the Wharton's jelly of human umbilical cord successfully. Immunocytochemistry showed that they were positive for several markers of mesenchymal stem cells (CD73, CD90, and CD105) and integrin markers (CD29 and CD44), but negative for a hematopoietic cell maker (CD45) and an endothelial cell marker (CD31). Their differentiation into osteocytes and adipocytes under specific conditions indicated that they had multi‐lineage differentiation potential. Therefore these results proved that the cells we obtained from Wharton's jelly were human umbilical cord mensenchymal stem cells (hUCMSCs). Using immunocytochemistry and Western blotting analysis, we found that after treatment with neuronal induction medium [NIM; consisting of brain‐derived neurotrophic factor (BDNF) and low‐serum media] for 14 days, hUCMSCs expressed a neuronal specific marker, microtubule associated protein 2 (MAP2), and extended neurite‐like processes. After treatment with NIM, supplemented with hippocampal cholinergic neurostimulating peptide (HCNP) or rat denervated hippocampal extract [rDHE; derived from rat fimbria fornix (FF) transected hippocampus], hUCMSCs expressed choline acetytransferase (ChAT) and this action could be enhanced when cells were cultured with NIM, supplemented with HCNP and rDHE in combination. ELISA showed that these ChAT‐positive cells could secrete acetylcholine (ACh). These findings indicate that hUCMSCs possess the potential of differentiation into functional ChAT‐positive cells in vitro and provide a new candidate of cells for the cell transplantation to treat Alzheimer's disease (AD).
Revised 14C dating of ice wedge growth in interior Alaska (USA) to MIS 2 reveals cold paleoclimate and carbon recycling in ancient permafrost terrain
Authors: Lachniet Matthew S. , Lawson Daniel E. , Sloat Alison R. 
Published: June 2012

AbstractEstablishing firm radiocarbon chronologies for Quaternary permafrost sequences remains a challenge because of the persistence of old carbon in younger deposits. To investigate carbon dynamics and establish ice wedge formation ages in Interior Alaska, we dated a late Pleistocene ice wedge, formerly assigned to Marine Isotope Stage (MIS) 3, and host sediments near Fairbanks, Alaska, with 24 radiocarbon analyses on wood, particulate organic carbon (POC), air-bubble CO2, and dissolved organic carbon (DOC). Our new CO2 and DOC ages are up to 11,170 yr younger than ice wedge POC ages, indicating that POC is detrital in origin. We conclude an ice wedge formation age between 28 and 22 cal ka BP during cold stadial conditions of MIS 2 and solar insolation minimum, possibly associated with Heinrich event 2 or the last glacial maximum. A DOC age for an ice lens in a thaw unconformity above the ice wedge returned a maximum age of 21,470 ± 200 cal yr BP. Our variable 14C data indicate recycling of older carbon in ancient permafrost terrain, resulting in radiocarbon ages significantly older than the period of ice-wedge activity. Release of ancient carbon with climatic warming will therefore affect the global 14C budget.
Current subsidiary peak in triggered lightning strokes
Authors: Wang Caixia , Jiang Rubin , Yang Jing , Liu Mingyuan 
Published: June 2012

Mainly based on the channel base current of the 0803 and 0902 flashes detected in the Shandong Artificial Triggering Lightning Experiment (SHATLE) from 2005 to 2010, the current waveforms of six return strokes and an RM process (a process characterized by both a return stroke and an M‐component) containing subsidiary peaks were analyzed. The percentage of strokes with subsidiary peak is approximately 17%. The amplitudes of the stroke primary and subsidiary peaks varied from 8.53 to 16.34 kA and 5.40 to 15.86 kA, respectively. The time intervals between the primary and the secondary peak varied from 6.3 to 12.0 μs. The strokes of the 0803 and 0902 flashes have different current waveform characteristics, indicating that the mechanisms generating the subsidiary peaks in the two lightning may be different. To learn more about the causes of forming the subsidiary peaks based on the assumption that channel branches and every peak corresponds to a physical process, a Heidler function model was used to simulate the current waveforms of four strokes and an RM in flash 0902. The simulated results indicated that the Heidler function component could reflect the physical characteristics of the peaks to some extent. Based on simulated results and comparison of waveforms, four possibilities of forming subsidiary peaks were proposed: channel branching, flashover along a triggering wire from a previous unsuccessful launch, the corona current or reflection of the current. Branching and flashover may be the main causes of generating the subsidiary peaks in 0902 and 0803 flashes, respectively.
Vertical heat transfer in the Arctic Ocean: The role of double‐diffusive mixing
Authors: Sirevaag Anders , Fer Ilker 
Published: June 2012

Microstructure profiles collected in the central Amundsen Basin are analyzed in order to quantify the role of double‐diffusive mixing for vertical heat transfer from the Atlantic layer. In the profiles, a persistent, but laterally incoherent thermohaline staircase structure is identified in the 200–260 m depth range. The staircase contains homogeneous layers with average height of 1.3 m and thin, high‐gradient interfaces with average temperature and salinity jumps of about 0.065°C and 0.015, respectively. When inferred from a commonly used diffusive convection parameterization, the average vertical heat flux within the staircase is 0.6 W m−2. This is one order of magnitude larger than the molecular diffusion alone and of the same order as the overall heat loss from the Atlantic layer in the deep basins of the Arctic Ocean. The parameterization is evaluated using observed turbulent heat fluxes and is found to overestimate diffusive convective fluxes with up to an order of magnitude, especially for weak thermal forcing (small temperature jumps in staircase). Staircases coexist with thermohaline intrusions in the vertical temperature and salinity profiles. Lomonosov Ridge is identified as a potential region for formation of intrusions. It is found that salt fingering is the dominant process during intrusion growth whereas diffusive convection is the dominant process in maintaining the intrusions at steady state in the deep basins.
Accurate relativistic energy-consistent pseudopotentials for the superheavy elements 111 to 118 including quantum electrodynamic effects
Authors: Hangele Tim , Dolg Michael , Hanrath Michael , Cao Xiaoyan , Schwerdtfeger Peter 
Published: June 2012

Energy-consistent two-component semi-local pseudopotentials for the superheavy elements with atomic numbers 111–118 have been adjusted to fully relativistic multi-configuration Dirac–Hartree–Fock calculations based on the Dirac–Coulomb Hamiltonian, including perturbative corrections for the frequency-dependent Breit interaction in the Coulomb gauge and lowest-order quantum electrodynamic effects. The pseudopotential core includes 92 electrons corresponding to the configuration [Xe]4f 145d105f 14. The parameters for the elements 111–118 were fitted by two-component multi-configuration Hartree–Fock calculations in the intermediate coupling scheme to the total energies of 267 up to 797 J levels arising from 31 up to 62 nonrelativistic configurations, including also anionic and highly ionized states, with mean absolute errors clearly below 0.02 eV for averages corresponding to nonrelativistic configurations. Primitive basis sets for one- and two-component pseudopotential calculations have been optimized for the ground and excited states and exhibit finite basis set errors with respect to the finite-difference Hartree–Fock limit below 0.01 and 0.02 eV, respectively. General contraction schemes have been applied to obtain valence basis sets of polarized valence double- to quadruple-zeta quality. Results of atomic test calculations in the intermediate coupling scheme at the Fock-space coupled-cluster level are in good agreement with those of corresponding fully relativistic all-electron calculations based on the Dirac–Coulomb–Breit Hamiltonian. The results demonstrate besides the well-known need of a relativistic treatment at the Dirac–Coulomb level also the necessity to include higher-order corrections for the superheavy elements.
Digital atom interferometer with single particle control on a discretized space-time geometry
Authors: Steffen Andreas , Alberti Andrea , Alt Wolfgang , Belmechri Noomen , Hild Sebastian , Karski Michał , Widera Artur , Meschede Dieter 
Published: June 2012

Engineering quantum particle systems, such as quantum simulators and quantum cellular automata, relies on full coherent control of quantum paths at the single particle level. Here we present an atom interferometer operating with single trapped atoms, where single particle wave packets are controlled through spin-dependent potentials. The interferometer is constructed from a sequence of discrete operations based on a set of elementary building blocks, which permit composing arbitrary interferometer geometries in a digital manner. We use this modularity to devise a space-time analogue of the well-known spin echo technique, yielding insight into decoherence mechanisms. We also demonstrate mesoscopic delocalization of single atoms with a separation-to-localization ratio exceeding 500; this result suggests their utilization beyond quantum logic applications as nano-resolution quantum probes in precision measurements, being able to measure potential gradients with precision 5 × 10
-4
in units of gravitational acceleration
g
.
When activity shapes the repertoire of second language learners
Authors: Masats Dolors , Nussbaum Luci , Unamuno Virginia 
Published: June 2012

Interactionists interested in second language acquisition postulate that learners’ competences are sensitive to the context in which they are put into play. Here we explore the language practices displayed, in a bilingual socio-educational milieu, by three dyads of English learners while carrying out oral communicative pair-work. In particular, we examine the role language choice plays in each task.

A first analysis of our data indicates that the learners’ language choices seem to reveal the linguistic norms operating in the community of practice they belong to. A second analysis reveals that they exploited their linguistic repertoires according to their interpretation of the task and to their willingness to complete it in English. Thus, in the first two tasks students relied on code-switching as a mechanism to solve communication failures, whereas the third task generated the use of a mixed repertoire as a means to complete the task in the target language.
National Survey of Practices to Prevent Healthcare-Associated Infections in Thailand: The Role of Safely Culture and Collaboratives
Authors: Apisarnthanarak Anucha , Greene M. Todd , Kennedy Edward H. , Khawcharoenporn Thana , Krein Sarah , Saint Sanjay 
Published: June 2012

Objective.To evaluate hospital characteristics and practices used by Thai hospitals to prevent catheter-associated urinary tract infection (CAUTI), central line-associated bloodstream infection (CLABSI), and ventilator-associated pneumonia (VAP), the 3 most common types of healthcare-associated infection (HAI) in Thailand.Design.Survey.Setting.Thai hospitals with an intensive care unit and 250 or more hospital bedsMethods.Between January 1, 2010, and October 31, 2010, research nurses collected data from all eligible hospitals. The survey assessed hospital characteristics and practices to prevent CAUTI, CLABSI, and VAP. Ordinal logistic regression was used to assess relationships between hospital characteristics and use of prevention practices.Results.A total of 204 (80%) of 256 hospitals responded. Most hospitals (93%) reported regularly using alcohol-based hand rub. The most frequently reported prevention practice by infection was as follows: for CAUTI, condom catheters in men (47%); for CLABSI, avoiding routine central venous catheter changes (85%); and for VAP, semirecumbent positioning (84%). Hospitals with peripherally inserted central catheter insertion teams were more likely to regularly use elements of the CLABSI prevention bundle. Greater safety scores were associated with regular use of several VAP prevention practices. The only hospital characteristic associated with increased use of at least 1 prevention practice for each infection was membership in an HAI collaborative.Conclusions.While reported adherence to hand hygiene was high, many of the prevention practices for CAUTI, CLABSI, and VAP were used infrequently in Thailand. Policies and interventions emphasizing specific infection prevention practices, establishing a strong institutional safety culture, and participating in collaboratives to prevent HAI may be beneficial.
Adequate Disinfection of a Split-Septum Needleless Intravascular Connector with a 5-Second Alcohol Scrub
Authors: Rupp Mark E. , Yu Stephanie , Huerta Tomas , Cavalieri R. Jennifer , Alter Roxanne , Fey Paul D. , Van Schooneveld Trevor , Anderson James R. 
Published: June 2012

Objective.Define optimum vascular catheter connector valve disinfection practices under laboratory and clinical conditions.Design.Prospective observational clinical survey and laboratory assessment of disinfection procedures.Setting.All adult inpatients at an academic healthcare center.Methods.In the clinical setting, contamination of needleless connectors was assessed in 6 weekly prevalence surveys in which the connector valves from central venous catheters (CVCs) in situ were cultured by pressing the connector diaphragm to an agar plate. Before culture, valves were disinfected by scrubbing the diaphragm with a 70% isopropyl alcohol pledget for 0, 5, 10, 15, or 30 seconds. In the laboratory, the diaphragms on 150 unused sterile connector valves were inoculated with 103, 105, or 108colony-forming units ofStaphylococcus epidermidisand allowed to dry. After disinfection of the diaphragms by scrubbing with a 70% isopropyl alcohol pledget for 0, 5, 10, 15, or 30 seconds, the valves were sampled by pressing the diaphragm to an agar plate.Results.In the clinical setting, 363 connector valves from patients with CVCs were sampled, and 66.7% of nondisinfected valves revealed bacterial contamination. After 5-second disinfection with an alcohol pledget, only 1 (1.4%) of 71 yielded microbial growth (P< .005). In the laboratory, at the 103and 105inoculum, all connector valves yielded sterile cultures when scrubbed for 5 or more seconds (P< .001). At the 108inoculum, 2 (20%) of 10 connector valves yielded minimal growth ofS. epidermidis.Conclusions.A 5-second scrub with a 70% isopropyl alcohol pledget yields adequate disinfection of a split-septum intravascular catheter connector valve under clinical and laboratory conditions.