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Electrically charged particles can be created by the decay of strong enough electric fields, a phenomenon known as the Schwinger mechanism1. By electromagnetic duality, a sufficiently strong magnetic field would similarly produce magnetic monopoles, if they exist2. Magnetic monopoles are hypothetical fundamental particles that are predicted by several theories beyond the standard model3-7 but have never been experimentally detected. Searching for the existence of magnetic monopoles via the Schwinger mechanism has not yet been attempted, but it is advantageous, owing to the possibility of calculating its rate through semi-classical techniques without perturbation theory, as well as that the production of the magnetic monopoles should be enhanced by their finite size8,9 and strong coupling to photons2,10. Here we present a search for magnetic monopole production by the Schwinger mechanism in Pb-Pb heavy ion collisions at the Large Hadron Collider, producing the strongest known magnetic fields in the current Universe11. It was conducted by the MoEDAL experiment, whose trapping detectors were exposed to 0.235 per nanobarn, or approximately 1.8 × 109, of Pb-Pb collisions with 5.02-teraelectronvolt center-of-mass energy per collision in November 2018. A superconducting quantum interference device (SQUID) magnetometer scanned the trapping detectors of MoEDAL for the presence of magnetic charge, which would induce a persistent current in the SQUID. Magnetic monopoles with integer Dirac charges of 1, 2 and 3 and masses up to 75 gigaelectronvolts per speed of light squared were excluded by the analysis at the 95% confidence level. This provides a lower mass limit for finite-size magnetic monopoles from a collider search and greatly extends previous mass bounds.
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The MoEDAL trapping detector consists of approximately 800 kg of aluminum volumes. It was exposed during run 2 of the LHC program to 6.46 fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point. Evidence for dyons (particles with electric and magnetic charge) captured in the trapping detector was sought by passing the aluminum volumes comprising the detector through a superconducting quantum interference device (SQUID) magnetometer. The presence of a trapped dyon would be signaled by a persistent current induced in the SQUID magnetometer. On the basis of a Drell-Yan production model, we exclude dyons with a magnetic charge ranging up to five Dirac charges (5g_{D}) and an electric charge up to 200 times the fundamental electric charge for mass limits in the range 870-3120 GeV and also monopoles with magnetic charge up to and including 5g_{D} with mass limits in the range 870-2040 GeV.
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MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794 kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0 fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to or above the Dirac charge are excluded in all samples. Monopole spins 0, ½, and 1 are considered and both velocity-independent and-dependent couplings are assumed. This search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.
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Loss-of-function variants in the MC1R gene cause recessive red or yellow coat-colour phenotypes in many species. The canine MC1R:c.916C>T (p.Arg306Ter) variant is widespread and found in a homozygous state in many uniformly yellow- or red-coloured dogs. We investigated cream-coloured Australian Cattle Dogs whose coat colour could not be explained by this variant. A genome-wide association study with 10 cream and 123 red Australian Cattle Dogs confirmed that the cream locus indeed maps to MC1R. Whole-genome sequencing of cream dogs revealed a single nucleotide variant within the MITF binding site of the canine MC1R promoter. We propose to designate the mutant alleles at MC1R:c.916C>T as e1 and at the new promoter variant as e2 . Both alleles segregate in the Australian Cattle Dog breed. When we considered both alleles in combination, we observed perfect association between the MC1R genotypes and the cream coat colour phenotype in a cohort of 10 cases and 324 control dogs. Analysis of the MC1R transcript levels in an e1 /e2 compound heterozygous dog confirmed that the transcript levels of the e2 allele were markedly reduced with respect to the e1 allele. We further report another MC1R loss-of-function allele in Alaskan and Siberian Huskies caused by a 2-bp deletion in the coding sequence, MC1R:c.816_817delCT. We propose to term this allele e3 . Huskies that carry two copies of MC1R loss-of-function alleles have a white coat colour.
Assuntos
Cães/genética , Cor de Cabelo/genética , Receptor Tipo 1 de Melanocortina/genética , Alelos , Animais , Austrália , Cruzamento , Estudos de Associação Genética/veterinária , Genótipo , Fenótipo , Regiões Promotoras Genéticas , Análise de Sequência de DNARESUMO
MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV pp collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.
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INTRODUCTION: In this case report we present a feline large granular lymphocyte (LGL) lymphoma, a rare morphologically distinct subtype of lymphoma, in a twelve-year-old female spayed domestic short hair cat, with high suspicion of leptomeningeal lymphomatosis due to magnetic resonance imaging findings and results of cerebral spinal fluid analyses. Diagnosis of LGL lymphoma was confirmed by means of blood cytology and polymerase chain reaction for antigen receptor rearrangements.
INTRODUCTION: Dans ce rapport de cas, nous présentons un Large Granular Lymphocyte (LGL) lymphome, un sous-type rare de lymphome, chez une chatte domestique à poil court stérilisée de douze ans, avec une forte suspicion de lymphomatose leptoméningée en raison des résultats de l'imagerie par résonance magnétique et de l'analyse du liquide céphalo-rachidien. Le diagnostic de LGL-lymphome a été confirmé par une cytologie sanguine et une réaction en chaîne de la polymérase pour les réarrangements des récepteurs d'antigènes.
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Doenças do Gato , Linfoma , Feminino , Gatos , Animais , Linfoma/veterinária , Reação em Cadeia da Polimerase/veterinária , Linfócitos , Doenças do Gato/diagnóstico por imagemRESUMO
INTRODUCTION: In this case report we present the rare case of a distally located peripheral nerve sheath tumor (PNST) of the left ulnar nerve in a two-year-old female Rottweiler dog. We discuss the clinical and diagnostic findings and the challenges of the diagnosis. The dog was successfully treated with a limb sparing partial neurectomy. After surgery, the dog did not show any pain or lameness on long term follow-up.
INTRODUCTION: Dans ce rapport de cas, nous présentons le rare cas d'une tumeur périphérique de la gaine du nerf ulnaire/cubital gauche chez une chienne Rottweiler de deux ans. Nous discutons les résultats cliniques et diagnostiques et les défis liés au diagnostic. Le chien a été traité avec succès par une neurectomie partielle. Après la chirurgie, lors du suivi à long terme, le chien n'a plus présenté ni de douleur ni de boiterie.
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Doenças do Cão , Neoplasias de Bainha Neural , Animais , Doenças do Cão/diagnóstico , Doenças do Cão/cirurgia , Cães , Feminino , Imageamento por Ressonância Magnética/veterinária , Neoplasias de Bainha Neural/diagnóstico , Neoplasias de Bainha Neural/cirurgia , Neoplasias de Bainha Neural/veterinária , Nervo Ulnar/patologia , Nervo Ulnar/cirurgiaRESUMO
Introduction: Collaborative care improves depression and anxiety outcomes. In this naturalistic, observational case study, we adapted an evidence-based depression collaborative care protocol for the assessment and treatment of posttraumatic stress disorder (PTSD) and sought to demonstrate that the protocol could be implemented in Veterans Affairs (VA) primary care. Method: Based on feedback from a content expert panel, clinical stakeholders, and a pilot study conducted in a postdeployment clinic, the original depression collaborative care protocol was modified to include PTSD assessment and support for PTSD medication adherence, self-management, and engagement in evidence-based PTSD care. Results: The modified program was implemented from November 2012 to March 2017, and 239 patients with PTSD were referred. Nearly two thirds (n = 185) enrolled, and they participated in the program for an average of 4 to 5 months and completed calls approximately once per month. Among patients with more than one assessment of clinical outcomes, 53.4% (n = 94) reported clinically significant improvement in depression on the Patient Health Questionnaire-9 (≥ 5-point decrease), and 42.2% (n = 35) reported clinically significant improvement on the PTSD Checklist (≥ 10-point decrease). Veterans and clinical staff described the modified collaborative care program positively in qualitative interviews. Discussion: Our findings suggest that a depression collaborative care program can be modified to support treatment of PTSD in primary care. The modified program was acceptable to both veterans and clinical staff and showed potential for positive clinical change in an uncontrolled quality improvement study. (PsycInfo Database Record (c) 2021 APA, all rights reserved).