1,614 research outputs found
Theory of magnetic spin and orbital Hall and Nernst effects in bulk ferromagnets
The magnetic spin Hall effect (MSHE) is an anomalous charge-to-spin
conversion phenomenon which occurs in ferromagnetic materials. In contrast to
the conventional spin Hall effect (SHE), being a time-reversal even effect, the
magnetic counterpart is time-reversal odd. In this work, we use ab initio
calculations to investigate the MSHE for the bulk ferromagnets Fe, Co, and Ni.
The magnitudes of the MSHE of Fe and Co are comparable to those of the SHE, but
the MSHE is strongly dependent on the electron lifetime and the MSHE and SHE
can moreover have opposite signs. For Ni the MSHE is smaller than the SHE, but
in general, the MSHE cannot be ignored for spin-orbit torques. Considering a
charge current we analyze how both the MSHE and SHE contribute to a total Hall
angle. We extend our analysis of the MSHE to its orbital counterpart, that is,
the magnetic orbital Hall effect (MOHE), for which we show that the MOHE is in
general smaller than the orbital Hall effect (OHE). We compute furthermore the
thermal analogs, i.e., the spin and orbital Nernst effects, and their magnetic
counterparts. Here our calculations show that the magnetic spin and orbital
Nernst effects of Ni are substantially larger than those of Fe and Co
Effectiveness of a Federal Healthy Start Program in Reducing Infant Mortality
Objective: Infant mortality is an important indicator of the health status of a community. In this analysis, we aimed to evaluate temporal changes in infant mortality rates (IMR) in the Central Hillsborough Healthy Start (CHHS) program service area in Tampa, Florida compared to rates in the rest of Hillsborough County and the state.
Method: We conducted a five-year (2010-2014) trends analysis using birth and infant death data extracted from the Florida Community Health Assessment Resource Tool Set (CHARTS). The number of infant deaths and live births were used to calculate and compare IMRs in the CHHS catchment area to those in the rest of Hillsborough County, and the state of Florida. Three-year centered moving averages were directly adjusted to account for differences in the racial/ethnic distribution of mothers across geographic areas.
Results: Between 2010 and 2014, the IMR decreased 42.8% in the CHHS service area (from 14.5 to 8.3 per 1,000 live births) compared to decreases of 10.1% and 7.7% in the rest of Hillsborough County and the state of Florida, respectively. Additionally, the infant mortality gap in the CHHS catchment area narrowed from 72% in 2010 to 14% in 2014 compared to the rest of the state, and was eliminated when compared to the rest of Hillsborough County.
Discussion: The absolute and relative decreases in IMR in the CHHS catchment area reflect the program’s effectiveness in decreasing disparity in infant mortality. The quality services provided by the CHHS program have had a significant positive impact on the families served
Regional Partnerships for Living Labs: the Case of Sicily and the MedLab Project
Abstract: This paper addresses the issue of how the Living Lab model can be integrated into regional development policy, through a “demand-pull” approach to innovation in which institutional innovation plays a key role in the form of bottom-up partnerships between a range of actors. The MedLab project, funded by the ERDF in the MED programme, addresses this issue with eight partners in seven Mediterranean regions. The paper first discusses the case of a concrete experience in building a regional Living Lab partnership in the Sicilian region and how the lessons learned shaped the MedLab approach and workplan. The first activities in MedLab are then presented as a more structured attempt at laying the ground for stable Living Lab governance mechanisms that will be tested in the project’s pilot projects. The ultimate aim is to permanently integrate the Living Lab approach as a transversal instrument of regional innovation policies in the Mediterranean basin, as a model for other regions in Europe
Three Dimensional Dynamic Analysis of Alborz Dam with Asphalt and Clay Cores
Alborz rockfill dam with a clay core is under construction in North of Iran, an area of heavy rainfall. Because of the difficulties in the construction of a clay core in a wet area, an alternative for the watertight element (asphalt core) was considered. During the design of Alborz dam, a dynamic response analysis of the asphalt core was performed using two-dimensional modeling based on the equivalent linear method. Considering the shortage of study on the seismic behavior of asphalt core dams and also the high level of risk of earthquakes in Iran, it was necessary that the dynamic behavior of this dam was studied using three-dimensional models. In this study, the dynamic response of Alborz dam for both variants of clay and asphalt cores has been investigated and three-dimensional dynamic (non-linear) analyses have been carried out using the explicit finite-difference program, FLAC3-D, under various hazard levels of earthquakes (DBL and MCL). The results obtained included: time histories of the response acceleration, displacement, shear stress and shear strains are presented in this paper. The dynamic response of the dam with a clay core and asphalt core are compared with each other
Water management for sustainable irrigated agriculture in the Zayandeh Rud Basin, Esfahan Province, Iran
Irrigation systemsCropping systemsIrrigated farmingRiver basinsTopographyGeomorphologyClimateHydrologyWater qualityGroundwaterSoil salinitySustainable agricultureIranEsfahan ProvinceZayandeh Rud BasinChadegan Reservoir
Prospects for intermediate mass black hole binary searches with advanced gravitational-wave detectors
We estimated the sensitivity of the upcoming advanced, ground-based
gravitational-wave observatories (the upgraded LIGO and Virgo and the KAGRA
interferometers) to coalescing intermediate mass black hole binaries (IMBHB).
We added waveforms modeling the gravitational radiation emitted by IMBHBs to
detectors' simulated data and searched for the injected signals with the
coherent WaveBurst algorithm. The tested binary's parameter space covers
non-spinning IMBHBs with source-frame total masses between 50 and 1050
and mass ratios between and 1. We found that
advanced detectors could be sensitive to these systems up to a range of a few
Gpc. A theoretical model was adopted to estimate the expected observation
rates, yielding up to a few tens of events per year. Thus, our results indicate
that advanced detectors will have a reasonable chance to collect the first
direct evidence for intermediate mass black holes and open a new, intriguing
channel for probing the Universe over cosmological scales.Comment: 9 pages, 4 figures, corrected the name of one author (previously
misspelled
Noninvasive PET Imaging and Tracking of Engineered Human Muscle Precursor Cells for Skeletal Muscle Tissue Engineering
Transplantation of human muscle precursor cells (hMPCs) is envisioned for the treatment of various muscle diseases. However, a feasible noninvasive tool to monitor cell survival, migration, and integration into the host tissue is still missing.
METHODS: In this study, we designed an adenoviral delivery system to genetically modify hMPCs to express a signaling-deficient form of human dopamine D2 receptor (hD2R). The gene expression levels of the receptor were evaluated by reverse transcriptase polymerase chain reaction, and infection efficiency was evaluated by fluorescent microscopy. The viability, proliferation, and differentiation capacity of the transduced cells, as well as their myogenic phenotype, were determined by flow cytometry analysis and fluorescent microscopy. (18)F-fallypride and (18)F-fluoromisonidazole, two well-established PET radioligands, were assessed for their potential to image engineered hMPCs in a mouse model and their uptakes were evaluated at different time points after cell inoculation in vivo. Biodistribution studies, autoradiography, and PET experiments were performed to determine the extent of signal specificity. To address feasibility for tracking hMPCs in an in vivo model, the safety of the adenoviral gene delivery was evaluated. Finally, the harvested tissues were histologically examined to determine whether survival of the transplanted cells was sustained at different time points.
RESULTS: Adenoviral gene delivery was shown to be safe, with no detrimental effects on the primary human cells. The viability, proliferation, and differentiation capacity of the transduced cells were confirmed, and flow cytometry analysis and fluorescent microscopy showed that their myogenic phenotype was sustained. (18)F-fallypride and (18)F-fluoromisonidazole were successfully synthesized. Specific binding of (18)F-fallypride to hD2R hMPCs was demonstrated in vitro and in vivo. Furthermore, the (18)F-fluoromisonidazole signal was high at the early stages. Finally, sustained survival of the transplanted cells at different time points was confirmed histologically, with formation of muscle tissue at the site of injection.
CONCLUSION: Our proposed use of a signaling-deficient hD2R as a potent reporter for in vivo hMPC PET tracking by (18)F-fallypride is a significant step toward potential noninvasive tracking of hD2R hMPCs and bioengineered muscle tissues in the clinic
Assessment of the intrinsic vulnerability of agricultural land to water and nitrogen losses: case studies in Italy and Greece
Abstract. LOS indices (abbr. of Losses) can be used for the assessment of the intrinsic vulnerability of agricultural land to water and nitrogen losses through percolation and runoff. The indices were applied on the lowland region of Ferrara Province (FP) in Italy and the upland region of Sarigkiol Basin (SB) in Greece. The most vulnerable zones in FP were the coastal areas consisting of high permeability sandy dunes and the areas close to riverbanks and palaeochannels, and in SB were the areas characterized by high slopes and high permeability soils at high altitude and areas belonging to the upper part of the alluvial plain close to the boundaries between agricultural land and mountainous regions. The application of LOS indices highlighted the specific features of both lowland and upland regions that contribute to water and nitrogen losses and showed their ability for use as tools in designing environmental management plans
Robust Chauvenet Outlier Rejection
Sigma clipping is commonly used in astronomy for outlier rejection, but the
number of standard deviations beyond which one should clip data from a sample
ultimately depends on the size of the sample. Chauvenet rejection is one of the
oldest, and simplest, ways to account for this, but, like sigma clipping,
depends on the sample's mean and standard deviation, neither of which are
robust quantities: Both are easily contaminated by the very outliers they are
being used to reject. Many, more robust measures of central tendency, and of
sample deviation, exist, but each has a tradeoff with precision. Here, we
demonstrate that outlier rejection can be both very robust and very precise if
decreasingly robust but increasingly precise techniques are applied in
sequence. To this end, we present a variation on Chauvenet rejection that we
call "robust" Chauvenet rejection (RCR), which uses three decreasingly
robust/increasingly precise measures of central tendency, and four decreasingly
robust/increasingly precise measures of sample deviation. We show this
sequential approach to be very effective for a wide variety of contaminant
types, even when a significant -- even dominant -- fraction of the sample is
contaminated, and especially when the contaminants are strong. Furthermore, we
have developed a bulk-rejection variant, to significantly decrease computing
times, and RCR can be applied both to weighted data, and when fitting
parameterized models to data. We present aperture photometry in a contaminated,
crowded field as an example. RCR may be used by anyone at
https://skynet.unc.edu/rcr, and source code is available there as well.Comment: 62 pages, 48 figures, 7 tables, accepted for publication in ApJ
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