1,106 research outputs found
Investigating Fatigue Performance on the Foamed Asphalt Specimens Generated Using Different Foam Properties
An evaluation of fatigue resistance for foamed asphalt mixture is very demanding since the binder is not continuously distributed on the aggregate surface and this mixtures contains water, the content of which dramatically affects the mechanical properties. This paper discusses the results of laboratory fatigue testingon the foamed asphalt mixtures in which the specimens are generated using three different foamed bitumen properties. Foamed bitumen as the binder was produced at three different foaming water content (FWC) at a temperature of 180oC using a 70/100 pen. The aggregates were mechanically mixed with foamed bitumen using a Hobart mixer. The resulting mixtures were then compacted using a gyratory compactor to generatespecimen with diameter of 100 mm. The specimens were fatigue tested at various stress levels at a temperature of 20oC following a curing period of 3 days at 40oC. Overall, fatigue performance of foamed asphalt can be identified based upon both stress and strain for mixtures produced at FWC 1%, 5%, and 10%
Three-dimensional track reconstruction for directional Dark Matter detection
Directional detection of Dark Matter is a promising search strategy. However,
to perform such detection, a given set of parameters has to be retrieved from
the recoiling tracks : direction, sense and position in the detector volume. In
order to optimize the track reconstruction and to fully exploit the data of
forthcoming directional detectors, we present a likelihood method dedicated to
3D track reconstruction. This new analysis method is applied to the MIMAC
detector. It requires a full simulation of track measurements in order to
compare real tracks to simulated ones. We conclude that a good spatial
resolution can be achieved, i.e. sub-mm in the anode plane and cm along the
drift axis. This opens the possibility to perform a fiducialization of
directional detectors. The angular resolution is shown to range between
20 to 80, depending on the recoil energy, which is however
enough to achieve a high significance discovery of Dark Matter. On the
contrary, we show that sense recognition capability of directional detectors
depends strongly on the recoil energy and the drift distance, with small
efficiency values (50%-70%). We suggest not to consider this information either
for exclusion or discovery of Dark Matter for recoils below 100 keV and then to
focus on axial directional data.Comment: 27 pages, 20 figure
Social impact analysis of products under a holistic approach: A case study in the meat product supply chain
Social impact assessment of products can be approached through different methodologies that need to be adapted to the particularities and features of the studied subject. Thus, the Social Life Cycle Assessment methodology can be used to assess different innovative practices of product manufacturing, under a circular economy approach, by identifying potential positive as well as negative impacts along products’ life cycle. This paper presents the results of the Social Life Cycle Impact Assessment of a reference product from the Spanish meat industry using existing and new innovative methods of social impact analysis. Worker discrimination, health and safety for workers, consumers and local community were identified as the social aspects with relevant significance into the business or for the influence on customer’s perception of the products studied. Therefore, results can represent a reference scenario for the future assessment of innovative solutions in the Spanish meet sector. Despite the scarce use of Social Life Cycle Impact Assessment, this case study is a good example of how this innovative kind of assessment can be helpful for companies to identify their weak and strong social performance areas and design strategies to improve in Social Responsibility Management. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Probing neutralino dark matter in the MSSM & the NMSSM with directional detection
We investigate the capability of directional detectors to probe neutralino
dark matter in the Minimal Supersymmetric Standard Model and the
Next-to-Minimal Supersymmetric Standard Model with parameters defined at the
weak scale. We show that directional detectors such as the future MIMAC
detector will probe spin dependent dark matter scattering on nucleons that are
beyond the reach of current spin independent detectors. The complementarity
between indirect searches, in particular using gamma rays from dwarf spheroidal
galaxies, spin dependent and spin independent direct search techniques is
emphasized. We comment on the impact of the negative results on squark searches
at the LHC. Finally, we investigate how the fundamental parameters of the
models can be constrained in the event of a dark matter signal.Comment: 21 pages, 16 figure
How Can Active Region Plasma Escape into the Solar Wind from below a Closed Helmet Streamer?
Recent studies show that active-region (AR) upflowing plasma, observed by the
EUV-Imaging Spectrometer (EIS), onboard Hinode, can gain access to open
field-lines and be released into the solar wind (SW) via magnetic-interchange
reconnection at magnetic null-points in pseudo-streamer configurations. When
only one bipolar AR is present on the Sun and it is fully covered by the
separatrix of a streamer, such as AR 10978 in December 2007, it seems unlikely
that the upflowing AR plasma can find its way into the slow SW. However,
signatures of plasma with AR composition have been found at 1 AU by Culhane et
al. (2014) apparently originating from the West of AR 10978. We present a
detailed topology analysis of AR 10978 and the surrounding large-scale corona
based on a potential-field source-surface (PFSS) model. Our study shows that it
is possible for the AR plasma to get around the streamer separatrix and be
released into the SW via magnetic reconnection, occurring in at least two main
steps. We analyse data from the Nan\c{c}ay Radioheliograph (NRH) searching for
evidence of the chain of magnetic reconnections proposed. We find a noise storm
above the AR and several varying sources at 150.9 MHz. Their locations suggest
that they could be associated with particles accelerated during the first-step
reconnection process and at a null point well outside of the AR. However, we
find no evidence of the second-step reconnection in the radio data. Our results
demonstrate that even when it appears highly improbable for the AR plasma to
reach the SW, indirect channels involving a sequence of reconnections can make
it possible.Comment: 26 pages, 10 figures. appears in Solar Physics, 201
Parallel Evolution of Quasi-separatrix Layers and Active Region Upflows
Persistent plasma upflows were observed with Hinode's EUV Imaging
Spectrometer (EIS) at the edges of active region (AR) 10978 as it crossed the
solar disk. We analyze the evolution of the photospheric magnetic and velocity
fields of the AR, model its coronal magnetic field, and compute the location of
magnetic null-points and quasi-sepratrix layers (QSLs) searching for the origin
of EIS upflows. Magnetic reconnection at the computed null points cannot
explain all of the observed EIS upflow regions. However, EIS upflows and QSLs
are found to evolve in parallel, both temporarily and spatially. Sections of
two sets of QSLs, called outer and inner, are found associated to EIS upflow
streams having different characteristics. The reconnection process in the outer
QSLs is forced by a large-scale photospheric flow pattern which is present in
the AR for several days. We propose a scenario in which upflows are observed
provided a large enough asymmetry in plasma pressure exists between the
pre-reconnection loops and for as long as a photospheric forcing is at work. A
similar mechanism operates in the inner QSLs, in this case, it is forced by the
emergence and evolution of the bipoles between the two main AR polarities. Our
findings provide strong support to the results from previous individual case
studies investigating the role of magnetic reconnection at QSLs as the origin
of the upflowing plasma. Furthermore, we propose that persistent reconnection
along QSLs does not only drive the EIS upflows, but it is also responsible for
a continuous metric radio noise-storm observed in AR 10978 along its disk
transit by the Nan\c{c}ay Radio Heliograph.Comment: 29 pages, 10 figure
The Higgs boson in the MSSM in light of the LHC
We investigate the expectations for the light Higgs signal in the MSSM in
different search channels at the LHC. After taking into account dark matter and
flavor constraints in the MSSM with eleven free parameters, we show that the
light Higgs signal in the channel is expected to be at most at
the level of the SM Higgs, while the from W fusion
and/or the can be enhanced. For the main discovery
mode, we show that a strong suppression of the signal occurs in two different
cases: low or large invisible width. A more modest suppression is
associated with the effect of light supersymmetric particles. Looking for such
modification of the Higgs properties and searching for supersymmetric partners
and pseudoscalar Higgs offer two complementary probes of supersymmetry.Comment: 19 pages, 8 figure
A New Kind of Quinonic-Antibiotic Useful Against Multidrug-Resistant S. aureus and E. faecium Infections
Indexación: Scopus.A rapid emergence of resistant bacteria is occurring worldwide, endangering the efficacy of antibiotics and reducing the therapeutic arsenal available for treatment of infectious diseases. In the present study, we developed a new class of compounds with antibacterial activity obtained by a simple, two step synthesis and screened the products for in vitro antibacterial activity against ATCC® strains using the broth microdilution method. The compounds exhibited minimum inhibitory concentrations (MIC) of 1⁻32 μg/mL against Gram-positive ATCC® strains. The structure⁻activity relationship indicated that the thiophenol ring is essential for antibacterial activity and the substituents on the thiophenol ring module, for antibacterial activity. The most promising compounds detected by screening were tested against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF) clinical isolates. We found remarkable activity against VREF for compounds 7 and 16, were the MIC50/90 were 2/4 µg/mL and 4/4 µg/mL, respectively, while for vancomycin the MIC50/90 was 256/512 µg/mL. Neither compound affected cell viability in any of the mammalian cell lines at any of the concentrations tested. These in vitro data show that compounds 7 and 16 have an interesting potential to be developed as new antibacterial drugs against infections caused by VREF.https://www.mdpi.com/1420-3049/23/7/177
Prevalence and Risk Factors of Mastitis among Dairy Buffaloes from the Departments of Antioquia and Córdoba, Colombia
Background: Mastitis is the most common disease among dairy buffaloes worldwide, and it significantly affects the economic profitability of buffalo farms as well as animal welfare and public health.
Methods: This study was conducted between 2018 and 2019 at the Colombian departments of Antioquia and Córdoba, where 41% of the country’s total buffalo population is concentrated. Overall, 1,018 dairy buffaloes, including 603 in Antioquia and 415 in Córdoba, distributed among 11 farms, were assessed in the study. These animals were evaluated using the California mastitis test (CMT) and somatic cell count (SCC) to determine the presence of subclinical mastitis (SM). They were considered positive for SM when the results of CMT were higher than traces and SCC was >200,000 cells/mL.
Results: The total prevalence of the disease was 7.9%, and microbiological culture was performed on the samples obtained from the SM-positive animals. The main isolated bacterium was coagulase-negative Staphylococcus. Furthermore, risk factors affecting milking routine, hygiene, and farm facilities were determined. Manual milking, milking in the barn, non-disinfection of milkers' hands, etc., were identified as risk factors for the disease.
Conclusion: To the best of our knowledge, this is the first large-scale study of mastitis among buffaloes in Colombia
Emerging energy sources' social acceptability: Evidence from marine-based energy projects
Any decrease in global warming and its effects can only occur with a substantial reduction in anthropogenic CO2 emissions. In this context, renewable energy sources, particularly emerging sources, may play a central role in accelerating the transition from fossil fuels to cleaner energy sources. Emerging energy sources are renewable and have the potential to reduce global warming emissions; however, they are in the early development stages. These technologies include enhanced geothermal processes, artificial photosynthesis, and marine energy. In this study, we assess the main attributes that determine the social acceptance of renewable marine energy projects, highlighting individual preferences and heterogeneity for these projects. The results show that energy generation, ecological impact, job creation, co-ownership, and distributional justice are statistically significant attributes that support projects. However, individual preferences are highly heterogeneous. The existence of distinct classes (two in this case) with different preferences for marine energy attributes indicates that the one-size-fits-all approach may be inappropriate. Instead, policymakers and energy producers should tailor their proposals to meet the needs of both groups, considering their preferences and concerns
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