14,110 research outputs found
Constraining the MSSM with Dark Matter indirect detection data
Recently, a claim of possible evidence for Dark Matter in data from the Fermi
LAT experiment was made by Goodenough and Hooper [8]. We test the Dark Matter
properties consistent with their claim in terms of the MSSM by a 24-dimensional
parameter scan using nested sampling, excluding all but a very small region of
the MSSM. Although this claim is very preliminary, and not made by the Fermi
LAT experiment, our scan shows a possible approach for the analysis of future
firm evidence from an indirect detection experiment, and its potential for
heavily constraining models
More positive group memberships are associated with greater resilience in Royal Air Force (RAF) personnel
© 2020 The Authors. British Journal of Social Psychology published by John Wiley & Sons Ltd on behalf of British Psychological Society In the current project, we examined how perceived group memberships (number, and characteristics, of), social and relational identification, and social identity leadership are associated with resilience in Royal Air Force (RAF) personnel. Based on social identity theorizing, we hypothesized positive associations between the number of groups, perceptions of their characteristics (e.g., positivity), and how they relate to each other (i.e., compatibility) and resilience (H1). We also hypothesized positive associations between both social identity leadership (H2) and resilience, and social and relational identification (H3) and resilience. Two hundred and forty-three personnel from 18 RAF bases completed an identity mapping exercise and measures of leadership, social and relational identification, and resilience. Our findings highlighted the importance of the association between positive group memberships and resilience, and social identification and resilience. Counter to our hypothesis, belonging to more groups was negatively associated with resilience, and there were non-significant relationships between three principles of social identity leadership and resilience, with embedding identity being significantly negatively associated with resilience. In support of social identity theorizing, the number of positive groups was positively associated with resilience, as was social identification. These findings indicate that, for RAF personnel, it is belonging to positive groups, both within and outside work, along with social identification, that is positively associated with resilience
Self-care in primary care: findings from a longitudinal comparison study.
To examine the effects of self-care training workshops for primary healthcare workers on frequently attending patients
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Determining SUSY model parameters and masses at the LHC using cross-sections, kinematic edges and other observables.
We address the problem of mass measurements of supersymmetric particles at
the Large Hadron Collider, using the ATLAS detector as an example. By using
Markov Chain sampling techniques to combine standard measurements of kinematic
edges in the invariant mass distributions of decay products with a measurement
of a missing cross-section, we show that the precision of mass
measurements at the LHC can be dramatically improved, even when we do not
assume that we have measured the kinematic endpoints precisely, or that we have
identified exactly which particles are involved in the decay chain causing the
endpoints. The generality of the technique is demonstrated in a preliminary
investigation of a non-universal SUGRA model, in which we relax the
requirements of mSUGRA by breaking the degeneracy of the GUT scale gaugino
masses. The model studied is compatible with the WMAP limits on dark matter
relic density
Nanostructured thermoelectric generator for energy harvesting
This paper presents the development processes towards a new generation of nanostructured thermoelectric generators for power harvesting from small temperature gradients by using a combination of traditional silicon microfabrication techniques, electroplating and submicron ion-track nanolithography. Polyimide nanotemplates with pore diameters ranging from 30nm to 120 nm were fabricated. Preliminary results for Bi2Te3 nanowires (50 and 120 nm diameter) electroplated into polycarbonate ion-track commercial membranes are presented. Bi2Te3 nanowires of R Ì 3m structure, with preferential orientation in the (015) and (110) crystallographic plans with nearly stoichiometric composition were electroplated. The fine-grained observed microstructure (6-10 nm) and (110) crystalline orientation appear extremely promising for improving thermoelectric material properties
Cenozoic epeirogeny of the Indian peninsula
Peninsular India is a cratonic region with asymmetric relief manifest by eastward tilting from the 1.5 km high Western Ghats escarpment toward the flood-plains of eastward-draining rivers. Oceanic residual depth measurements on either side of India show that this west-east asymmetry is broader scale, occurring over distances of >2,000 km. Admittance analysis of free-air gravity and topography shows that the elastic thickness is 10 ± 3 km, suggesting that regional uplift is not solely caused by flexural loading. To investigate how Indian physiography is generated, we have jointly inverted 530 river profiles to determine rock uplift rate as a function of space and time. Key erosional parameters are calibrated using independent geologic constraints (e.g. emergent marine deposits, elevated paleosurfaces, uplifted lignite deposits). Our results suggest that regional tilt grew at rates of up to 0.1 mm aâŸÂč between 25 Ma and the present day. Neogene uplift initiated in the south and propagated northward along the western margin. This calculated history is corroborated by low-temperature ther- mochronologic observations, by sedimentary flux of clastic deposits into the Krishna- Godavari delta, and by sequence stratigraphic architecture along adjacent rifted margins. Onset of regional uplift predates intensification of the Indian monsoon at 8 Ma, suggesting that rock uplift rather than climatic change is responsible for modern-day relief. A positive correlation between residual depth measure- ments and shear wave velocities beneath the lithosphere suggests that regional uplift is generated and maintained by temperature anomalies of ±100 â°C within a 200 ± 25 km thick asthenospheric channel
Reduction of Proximity Effects on UHF Passive RFID Systems by Using Tags with Polarization Diversity
A new technique that enables passive ultra high fre-
quency (UHF) radio frequency identification (RFID) tags to be
read when they are placed in close proximity in an array is pre-
sented. This paper demonstrates that, in a linear tag array with
a tag separation of 1 cm, the interaction between the backscat-
tered waves and incident wave causes a significant degradation in
tag sensitivity. It is found that the use of tags that have polariza-
tion diversity can improve the read performance when they are
placed in close proximity to one another compared with conven-
tional linear tags. Two ways of achieving polarization diversity are
studied in this paper, namely: 1) using a circularly polarized tag
and 2) using a cross-polarized tag pair. Both methods show an
improvement in close proximity read performance and it is exper-
imentally demonstrated that by using cross-polarized tag pairs in
an array, one achieves on average a 2.6-dB increase in read power
margin for a 57-tag array with 1 cm separation compared with
using conventional linearly polarized tags.This work has been supported by UK Engineering and
Physical Science Research Council
via the COPOSII project.This is the final published version. It first appeared at http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7042269
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Low-Cost MIMO radio over fiber system for multiservice das using double sideband frequency translation
In this paper, a novel low-cost DSB frequency translation system is experimentally demonstrated and its theory is mathematically proved. The new system is capable of transmitting wideband LTE MIMO signals and supporting multiple services. Experimentally, 2Ă2 LTE MIMO channels with 20MHz bandwidth, and a 700MHz carrier frequency, are transmitted simultaneously along with an IEEE 802.11g signal (54Mbps) over a 300m length of multi-mode fiber (MMF). The MIMO channel matrix of the system is retrieved and the condition number is calculated. It can be seen in the experimental results that the system is well conditioned, has a low error vector magnitude (EVM) and the transmission of the MIMO signals has negligible effect on the IEEE 802.11g signal. The use of a preamplifier minimizes the non-linearity introduced by the frequency mixers, resulting in a high spurious-free dynamic range (SFDR). Compared to a single sideband (SSB) system, where multiple filters are used and two channels encounter different EVMs, the new DSB system avoids unnecessary filtering and the impairments introduced will be the same for both channels. Therefore it can be concluded that the improved MIMO over fiber system using DSB frequency translation technology is a potential low-cost solution for multiservice MIMO-enabled distributed antenna systems (DAS).This work was supported in part of the UK Engineering and Physical Sciences Research Council via the COPOS II grant and the European Community via the FP7 programme Quaternian project.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/JLT.2016.258208
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Experimental comparison of antenna clustering strategies in MIMO distributed antenna systems
In this paper the effect of partitioning arrays of transmitting antennas into spatially separated clusters on the condition number and capacity of MIMO wireless systems is examined using experimental channel measurements of an indoor MIMO-enabled distributed antenna system (DAS). It is first shown for a 3 _ 2 MIMO system that distributing the transmit antennas into spatially separated clusters provides an improvement in channel conditioning (_1dB) and hence capacity, in line with previous findings. Next, a configuration with 6 transmit antennas and 2 receive antennas is examined and it is found that when it is operated as a 6 _ 2 MIMO system, it makes negligible difference to the conditioning of the channel whether the transmit antennas are grouped into 3 clusters of 2 antennas or 2 clusters of 3 antennas. The capacity varies by only a small amount (_%1) between the two clustering schemes, which can be accounted for by environment-specific signal-tonoise ratio (SNR) effects. It is then concluded that for the two typical indoor DAS scenarios tested here, if sufficient transmit diversity is provided (i.e. there are a relatively large number of transmit antennas compared to receive antennas), greater spatial distribution through increased clustering provides diminishing performance improvements. Given the typically lower installation cost of less distributed arrangements, they may then be a preferred option in commercial DAS deployments.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/VTCFall.2014.696597
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