12,207 research outputs found
Skylab short-lived event alert program
During the three manned Skylab missions, the Center for Short-Lived Phenomena (CSLP) reported a total of 39 significant events to the Johnson Space Center (JSC) as part of the Skylab Short-Lived Event Alert Program. The telegraphed daily status reports included the names and locations of the events, the track number and revolution number during which the event could be observed, the time (GMT) to within plus or minus 2 sec when Skylab was closest to the event area, and the light condition (daylight or darkness) at that time and place. The messages sent to JSC during the Skylab 4 mission also included information pertaining to ground-truth studies and observations being conducted on the events. Photographic priorities were assigned for each event
Hemagglutinin sequence conservation guided stem immunogen design from influenza A H3 subtype
Seasonal epidemics caused by influenza A (H1 and H3 subtypes) and B viruses are a major global health threat. The traditional, trivalent influenza vaccines have limited efficacy because of rapid antigenic evolution of the circulating viruses. This antigenic variability mediates viral escape from the host immune responses, necessitating annual vaccine updates. Influenza vaccines elicit a protective antibody response, primarily targeting the viral surface glycoprotein hemagglutinin (HA). However, the predominant humoral response is against the hypervariable head domain of HA, thereby restricting the breadth of protection. In contrast, the conserved, subdominant stem domain of HA is a potential ‘universal’ vaccine candidate. We designed an HA stem-fragment immunogen from the 1968 pandemic H3N2 strain (A/Hong Kong/1/68) guided by a comprehensive H3 HA sequence conservation analysis. The biophysical properties of the designed immunogen were further improved by C-terminal fusion of a trimerization motif, ‘isoleucine-zipper’ or ‘foldon’. These immunogens elicited cross-reactive, antiviral antibodies and conferred partial protection against a lethal, homologous HK68 virus challenge in vivo. Furthermore, bacterial expression of these immunogens is economical and facilitates rapid scale-up
Collider Interplay for Supersymmetry, Higgs and Dark Matter
We discuss the potential impacts on the CMSSM of future LHC runs and possible
electron-positron and higher-energy proton-proton colliders, considering
searches for supersymmetry via MET events, precision electroweak physics, Higgs
measurements and dark matter searches. We validate and present estimates of the
physics reach for exclusion or discovery of supersymmetry via MET searches at
the LHC, which should cover the low-mass regions of the CMSSM parameter space
favoured in a recent global analysis. As we illustrate with a low-mass
benchmark point, a discovery would make possible accurate LHC measurements of
sparticle masses using the MT2 variable, which could be combined with
cross-section and other measurements to constrain the gluino, squark and stop
masses and hence the soft supersymmetry-breaking parameters m_0, m_{1/2} and
A_0 of the CMSSM. Slepton measurements at CLIC would enable m_0 and m_{1/2} to
be determined with high precision. If supersymmetry is indeed discovered in the
low-mass region, precision electroweak and Higgs measurements with a future
circular electron-positron collider (FCC-ee, also known as TLEP) combined with
LHC measurements would provide tests of the CMSSM at the loop level. If
supersymmetry is not discovered at the LHC, is likely to lie somewhere along a
focus-point, stop coannihilation strip or direct-channel A/H resonance funnel.
We discuss the prospects for discovering supersymmetry along these strips at a
future circular proton-proton collider such as FCC-hh. Illustrative benchmark
points on these strips indicate that also in this case FCC-ee could provide
tests of the CMSSM at the loop level.Comment: 47 pages, 26 figure
Linux kernel compaction through cold code swapping
There is a growing trend to use general-purpose operating systems like Linux in embedded systems. Previous research focused on using compaction and specialization techniques to adapt a general-purpose OS to the memory-constrained environment, presented by most, embedded systems. However, there is still room for improvement: it has been shown that even after application of the aforementioned techniques more than 50% of the kernel code remains unexecuted under normal system operation. We introduce a new technique that reduces the Linux kernel code memory footprint, through on-demand code loading of infrequently executed code, for systems that support virtual memory. In this paper, we describe our general approach, and we study code placement algorithms to minimize the performance impact of the code loading. A code, size reduction of 68% is achieved, with a 2.2% execution speedup of the system-mode execution time, for a case study based on the MediaBench II benchmark suite
The NUHM2 after LHC Run 1
We make a frequentist analysis of the parameter space of the NUHM2, in which
the soft supersymmetry (SUSY)-breaking contributions to the masses of the two
Higgs multiplets, , vary independently from the universal soft
SUSY-breaking contributions to the masses of squarks and sleptons. Our
analysis uses the MultiNest sampling algorithm with over points
to sample the NUHM2 parameter space. It includes the ATLAS and CMS Higgs mass
measurements as well as their searches for supersymmetric jets + MET signals
using the full LHC Run~1 data, the measurements of by
LHCb and CMS together with other B-physics observables, electroweak precision
observables and the XENON100 and LUX searches for spin-independent dark matter
scattering. We find that the preferred regions of the NUHM2 parameter space
have negative SUSY-breaking scalar masses squared for squarks and sleptons,
, as well as . The tension present in the
CMSSM and NUHM1 between the supersymmetric interpretation of and
the absence to date of SUSY at the LHC is not significantly alleviated in the
NUHM2. We find that the minimum with 21 degrees of freedom
(dof) in the NUHM2, to be compared with in the
CMSSM, and in the NUHM1. We find that the
one-dimensional likelihood functions for sparticle masses and other observables
are similar to those found previously in the CMSSM and NUHM1.Comment: 20 pages latex, 13 figure
The pMSSM10 after LHC Run 1
We present a frequentist analysis of the parameter space of the pMSSM10, in
which the following 10 soft SUSY-breaking parameters are specified
independently at the mean scalar top mass scale Msusy = Sqrt[M_stop1 M_stop2]:
the gaugino masses M_{1,2,3}, the 1st-and 2nd-generation squark masses M_squ1 =
M_squ2, the third-generation squark mass M_squ3, a common slepton mass M_slep
and a common trilinear mixing parameter A, the Higgs mixing parameter mu, the
pseudoscalar Higgs mass M_A and tan beta. We use the MultiNest sampling
algorithm with 1.2 x 10^9 points to sample the pMSSM10 parameter space. A
dedicated study shows that the sensitivities to strongly-interacting SUSY
masses of ATLAS and CMS searches for jets, leptons + MET signals depend only
weakly on many of the other pMSSM10 parameters. With the aid of the Atom and
Scorpion codes, we also implement the LHC searches for EW-interacting
sparticles and light stops, so as to confront the pMSSM10 parameter space with
all relevant SUSY searches. In addition, our analysis includes Higgs mass and
rate measurements using the HiggsSignals code, SUSY Higgs exclusion bounds, the
measurements B-physics observables, EW precision observables, the CDM density
and searches for spin-independent DM scattering. We show that the pMSSM10 is
able to provide a SUSY interpretation of (g-2)_mu, unlike the CMSSM, NUHM1 and
NUHM2. As a result, we find (omitting Higgs rates) that the minimum chi^2/dof =
20.5/18 in the pMSSM10, corresponding to a chi^2 probability of 30.8 %, to be
compared with chi^2/dof = 32.8/24 (31.1/23) (30.3/22) in the CMSSM (NUHM1)
(NUHM2). We display 1-dimensional likelihood functions for SUSY masses, and
show that they may be significantly lighter in the pMSSM10 than in the CMSSM,
NUHM1 and NUHM2. We discuss the discovery potential of future LHC runs, e+e-
colliders and direct detection experiments.Comment: 47 pages, 29 figure
Strong extinction of a far-field laser beam by a single quantum dot
Through the utilization of index-matched GaAs immersion lens techniques we
demonstrate a record extinction (12%) of a far-field focused laser by a single
InAs/GaAs quantum dot. This contrast level enables us to report for the first
time resonant laser transmission spectroscopy on a single InAs/GaAs quantum dot
without the need for phase-sensitive lock-in detection
The Importance of Audit Firm Characteristics and the Drivers of Auditor Change in UK Listed Companies
This paper explores the importance of audit firm characteristics and the factors motivating auditor change based on questionnaire responses from 210 listed UK companies (a response rate of 70%). Twenty-nine potentially desirable auditor characteristics are identified from the extant literature and their importance elicited. Exploratory factor analysis reduces these variables to eight uncorrelated underlying dimensions: reputation/quality; acceptability to third parties; value for money; ability to provide non-audit services; small audit firm; specialist industry knowledge; non-Big Six large audit firm; and geographical proximity. Insights into the nature of 'the Big Six factor' emerge. Two thirds of companies had recently considered changing auditors; the main reasons cited being audit fee level, dissatisfaction with audit quality and changes in top management. Of those companies that considered change, 73% did not actually do so, the main reasons cited being fee reduction by the incumbent and avoidance of disruption. Thus audit fee levels are both a key precipitator of change and a key factor in retaining the status quo
Design, Construction, Operation and Performance of a Hadron Blind Detector for the PHENIX Experiment
A Hadron Blind Detector (HBD) has been developed, constructed and
successfully operated within the PHENIX detector at RHIC. The HBD is a
Cherenkov detector operated with pure CF4. It has a 50 cm long radiator
directly coupled in a window- less configuration to a readout element
consisting of a triple GEM stack, with a CsI photocathode evaporated on the top
surface of the top GEM and pad readout at the bottom of the stack. This paper
gives a comprehensive account of the construction, operation and in-beam
performance of the detector.Comment: 51 pages, 39 Figures, submitted to Nuclear Instruments and Method
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