A novel technique using a set of artificial neural networks to identify and split merged measurements created by multiple charged particles in the ATLAS pixel detector is presented. Such merged ...measurements are a common feature of boosted physics objects such as tau leptons or strongly energetic jets where particles are highly collimated. The neural networks are trained using Monte Carlo samples produced with a detailed detector simulation. The performance of the splitting technique is quantified using LHC data collected by the ATLAS detector and Monte Carlo simulation. The number of shared hits per track is significantly reduced, particularly in boosted systems, which increases the reconstruction efficiency and quality. The improved position and error estimates of the measurements lead to a sizable improvement of the track and vertex resolution.
Searches for heavy particles decaying to a pair of tau leptons, and searches for pair produced thirdgeneration scalar leptoquarks decaying to a b-jet and a tau lepton are reported. The studies use ...the full data sample recorded in 2011 at radicals = 7 TeV centre-of-mass energy by the ATLAS experiment at the LHC.
ATLAS offline data quality monitoring Adelman, J; Baak, M; Boelaert, N ...
Journal of physics. Conference series,
04/2010, Letnik:
219, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The ATLAS experiment at the Large Hadron Collider reads out 100 Million electronic channels at a rate of 200 Hz. Before the data are shipped to storage and analysis centres across the world, they ...have to be checked to be free from irregularities which render them scientifically useless. Data quality offline monitoring provides prompt feedback from full first-pass event reconstruction at the Tier-0 computing centre and can unveil problems in the detector hardware and in the data processing chain. Detector information and reconstructed proton-proton collision event characteristics are distilled into a few key histograms and numbers which are automatically compared with a reference. The results of the comparisons are saved as status flags in a database and are published together with the histograms on a web server. They are inspected by a 24/7 shift crew who can notify on-call experts in case of problems and in extreme cases signal data taking abort.
T lymphocytes are critical for effective immunity, and the ability to study their behavior in vitro can facilitate major insights into their development, function, and fate. However, the composition ...of human plasma differs from conventional media, and we hypothesized that such differences could impact immune cell physiology. Here, we showed that relative to the medium typically used to culture lymphocytes (RPMI), a physiologic medium (human plasma-like medium; HPLM) induced markedly different transcriptional responses in human primary T cells and in addition, improved their activation upon antigen stimulation. We found that this medium-dependent effect on T cell activation is linked to Ca2+, which is six-fold higher in HPLM than in RPMI. Thus, a medium that more closely resembles human plasma has striking effects on T cell biology, further demonstrates that medium composition can profoundly affect experimental results, and broadly suggests that physiologic media may offer a valuable way to study cultured immune cells.
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•Activation of T lymphocytes in plasma-like medium is much more efficient•RPMI is severely hypocalcemic relative to human plasma and this impacts activation•Non-physiological levels of nutrients in RPMI alter lymphocyte metabolism
Biological Sciences; Immunology; Immunological Methods
Inborn errors of immunity (IEIs) unveil regulatory pathways of human immunity. We describe a new IEI caused by mutations in the GTPase of the immune-associated protein 6 (GIMAP6) gene in patients ...with infections, lymphoproliferation, autoimmunity, and multiorgan vasculitis. Patients and Gimap6-/- mice show defects in autophagy, redox regulation, and polyunsaturated fatty acid (PUFA)-containing lipids. We find that GIMAP6 complexes with GABARAPL2 and GIMAP7 to regulate GTPase activity. Also, GIMAP6 is induced by IFN-γ and plays a critical role in antibacterial immunity. Finally, we observed that Gimap6-/- mice died prematurely from microangiopathic glomerulosclerosis most likely due to GIMAP6 deficiency in kidney endothelial cells.
At the ATLAS experiment, the Detector Control System (DCS) is used to oversee detector conditions and supervise the running of equipment. It is essential that information from the DCS about the ...status of individual sub-detectors be extracted and taken into account when determining the quality of data taken and its suitability for different analyses. DCS information is written to the ATLAS conditions database and then summarised to provide a status flag for each sub-detector and displayed on the web. We discuss how this DCS information should be used, and the technicalities of making this summary.
Rapid allograft infection complicates liver transplantation (LT) in patients with hepatitis C virus (HCV). Pegylated interferon‐α and ribavirin therapy after LT has significant toxicity and limited ...efficacy. The effect of a human monoclonal antibody targeting the HCV E2 glycoprotein (MBL‐HCV1) on viral clearance was examined in a randomized, double‐blind, placebo‐controlled pilot study in patients infected with HCV genotype 1a undergoing LT. Subjects received 11 infusions of 50 mg/kg MBL‐HCV1 (n = 6) or placebo (n = 5) intravenously with three infusions on day of transplant, a single infusion on days 1 through 7 and one infusion on day 14 after LT. MBL‐HCV1 was well‐tolerated and reduced viral load for a period ranging from 7 to 28 days. Median change in viral load (log10 IU/mL) from baseline was significantly greater (p = 0.02) for the antibody‐treated group (range −3.07 to −3.34) compared to placebo group (range −0.331 to −1.01) on days 3 through 6 posttransplant. MBL‐HCV1 treatment significantly delayed median time to viral rebound compared to placebo treatment (18.7 days vs. 2.4 days, p < 0.001). As with other HCV monotherapies, antibody‐treated subjects had resistance‐associated variants at the time of viral rebound. A combination study of MBL‐HCV1 with a direct‐acting antiviral is underway.
Administration of a human monoclonal antibody to HCV E2 glycoprotein during the peritransplant period delays viral rebound after liver transplantation.
This document summarises the current theoretical and experimental status of the di-Higgs boson production searches, and of the direct and indirect constraints on the Higgs boson self-coupling, with ...the wish to serve as a useful guide for the next years. The document discusses the theoretical status, including state-of-the-art predictions for di-Higgs cross sections, developments on the effective field theory approach, and studies on specific new physics scenarios that can show up in the di-Higgs final state. The status of di-Higgs searches and the direct and indirect constraints on the Higgs self-coupling at the LHC are presented, with an overview of the relevant experimental techniques, and covering all the variety of relevant signatures. Finally, the capabilities of future colliders in determining the Higgs self-coupling are addressed, comparing the projected precision that can be obtained in such facilities. The work has started as the proceedings of the Di-Higgs workshop at Colliders, held at Fermilab from the 4th to the 9th of September 2018, but it went beyond the topics discussed at that workshop and included further developments. FERMILAB-CONF-19-468-E-T, LHCHXSWG-2019-005
The purpose of the present study was to quantify elimination kinetics of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in adult green frogs (Rana clamitans) and leopard ...frogs (Rana pipiens). Three experiments were conducted: PCB elimination rate constants were determined for both frog species, and PAH elimination rate constants were determined for leopard frogs only. In green frogs, significant PCB elimination rate constants ranged from 0.013 to 0.04 d−1 (time for frogs to achieve 90% steady state with water t90 = 57.8‐178.2 d). In leopard frogs, significant PCB elimination rate constants ranged from 0.004 to 0.047 d−1 (t90 = 48.8‐657.9 d). Polycyclic aromatic hydrocarbon elimination in leopard frogs was faster than PCB elimination in either frog species: Significant PAH rate constants ranged from 0.069 to 0.188 d−1 (t90 = 12.2‐33.5 d). In both species, and for both PCBs and PAHs, a significant inverse relationship was found between the chemical elimination rate constant and Kow. These results show that adult anurans have relatively low elimination rates of PCBs but exhibit a small capacity for metabolic biotransformation of PAHs that is comparable to that of invertebrates but lower than that of fish. These findings suggest that adult amphibians have the potential to be used as biomonitors for persistent organic chemicals.
The ATLAS semiconductor tracker end-cap module Abdesselam, A.; Adkin, P.J.; Allport, P.P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2007, Letnik:
575, Številka:
3
Journal Article
Recenzirano
The challenges for the tracking detector systems at the LHC are unprecedented in terms of the number of channels, the required read-out speed and the expected radiation levels. The ATLAS ...Semiconductor Tracker (SCT) end-caps have a total of about 3
million electronics channels each reading out every 25
ns into its own on-chip
3.3
μ
s
buffer. The highest anticipated dose after 10 years operation is
1.4
×
10
14
cm
-
2
in units of 1
MeV neutron equivalent (assuming the damage factors scale with the non-ionising energy loss). The forward tracker has 1976 double-sided modules, mostly of area
∼
70
cm
2
, each having
2
×
768
strips read out by six ASICs per side. The requirement to achieve an average perpendicular radiation length of 1.5%
X
0
, while coping with up to 7
W dissipation per module (after irradiation), leads to stringent constraints on the thermal design. The additional requirement of
1500
e
-
equivalent noise charge (ENC) rising to only
1800
e
-
ENC after irradiation, provides stringent design constraints on both the high-density Cu/Polyimide flex read-out circuit and the ABCD3TA read-out ASICs. Finally, the accuracy of module assembly must not compromise the
16
μ
m
(
r
φ
)
resolution perpendicular to the strip directions or
580
μ
m
radial resolution coming from the 40
mrad front-back stereo angle.
A total of 2210 modules were built to the tight tolerances and specifications required for the SCT. This was 234 more than the 1976 required and represents a yield of 93%. The component flow was at times tight, but the module production rate of 40–50 per week was maintained despite this. The distributed production was not found to be a major logistical problem and it allowed additional flexibility to take advantage of where the effort was available, including any spare capacity, for building the end-cap modules. The collaboration that produced the ATLAS SCT end-cap modules kept in close contact at all times so that the effects of shortages or stoppages at different sites could be rapidly resolved.
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