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1.
Phys Rev Lett ; 131(3): 031802, 2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37540851

RESUMO

We report the direct observation of muon neutrino interactions with the SND@LHC detector at the Large Hadron Collider. A dataset of proton-proton collisions at sqrt[s]=13.6 TeV collected by SND@LHC in 2022 is used, corresponding to an integrated luminosity of 36.8 fb^{-1}. The search is based on information from the active electronic components of the SND@LHC detector, which covers the pseudorapidity region of 7.2<η<8.4, inaccessible to the other experiments at the collider. Muon neutrino candidates are identified through their charged-current interaction topology, with a track propagating through the entire length of the muon detector. After selection cuts, 8 ν_{µ} interaction candidate events remain with an estimated background of 0.086 events, yielding a significance of about 7 standard deviations for the observed ν_{µ} signal.

2.
Rep Prog Phys ; 85(2)2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-34942603

RESUMO

In this paper, we describe the potential of the LHCb experiment to detect stealth physics. This refers to dynamics beyond the standard model that would elude searches that focus on energetic objects or precision measurements of known processes. Stealth signatures include long-lived particles and light resonances that are produced very rarely or together with overwhelming backgrounds. We will discuss why LHCb is equipped to discover this kind of physics at the Large Hadron Collider and provide examples of well-motivated theoretical models that can be probed with great detail at the experiment.

3.
Phys Rev Lett ; 126(2): 021801, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33512189

RESUMO

We investigate collisional decay of the axial charge in an electron-photon plasma at temperatures 10 MeV-100 GeV. We demonstrate that the decay rate of the axial charge is first order in the fine-structure constant Γ_{flip}∝αm_{e}^{2}/T and thus orders of magnitude greater than the naive estimate which has been in use for decades. This counterintuitive result arises through infrared divergences regularized at high temperature by environmental effects. The decay of axial charge plays an important role in the problems of leptogenesis and cosmic magnetogenesis.

4.
Phys Rev Lett ; 115(16): 161301, 2015 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-26550860

RESUMO

We detect a line at 3.539±0.011 keV in the deep exposure data set of the Galactic center region, observed with the x-ray multi-mirror mission Newton. The dark matter interpretation of the signal observed in the Perseus galaxy cluster, the Andromeda galaxy [A. Boyarsky et al., Phys. Rev. Lett. 113, 251301 (2014)], and in the stacked spectra of galaxy clusters [E. Bulbul et al., Astrophys. J. 789, 13 (2014)], together with nonobservation of the line in blank-sky data, put both lower and upper limits on the possible intensity of the line in the Galactic center data. Our result is consistent with these constraints for a class of Milky Way mass models, presented previously by observers, and would correspond to the radiative decay dark matter lifetime, τDM∼6-8×10(27) sec. Although it is hard to exclude an astrophysical origin of this line based on the Galactic center data alone, this is an important consistency check of the hypothesis that encourages us to check it with more observational data that are expected by the end of 2015.

5.
Phys Rev Lett ; 113(25): 251301, 2014 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-25554871

RESUMO

We report a weak line at 3.52±0.02 keV in x-ray spectra of the Andromeda galaxy and the Perseus galaxy cluster observed by the metal-oxide-silicon (MOS) and p-n (PN) CCD cameras of the XMM-Newton telescope. This line is not known as an atomic line in the spectra of galaxies or clusters. It becomes stronger towards the centers of the objects; is stronger for Perseus than for M31; is absent in the spectrum of a deep "blank sky" data set. Although for each object it is hard to exclude that the feature is due to an instrumental effect or an atomic line, it is consistent with the behavior of a dark matter decay line. Future (non-)detections of this line in multiple objects may help to reveal its nature.

6.
Phys Rev Lett ; 104(19): 191301, 2010 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-20866958

RESUMO

We discuss the universal relation between density and size of observed dark matter halos that was recently shown to hold on a wide range of scales, from dwarf galaxies to galaxy clusters. Predictions of cold dark matter (ΛCDM) N-body simulations are consistent with this relation. We demonstrate that this property of ΛCDM can be understood analytically in the secondary infall model. Qualitative understanding given by this model provides a new way to predict which deviations from ΛCDM or large-scale modifications of gravity can affect universal behavior and, therefore, to constrain them observationally.

7.
Surgery ; 98(3): 594-7, 1985 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-4035577

RESUMO

Patients with esophageal atresia and a distal tracheoesophageal fistula with associated conditions contributing to decreased pulmonary compliance present special problems in management. In the face of positive pressure ventilation, the fistula acts as a vent preventing adequate ventilatory effort from reaching the lungs. A thoracic approach to ligate or divide the fistula carries with it a high mortality rate. A technique is described whereby a silicone rubber band is applied to the gastroesophageal junction to effectively occlude the esophagus. It is designed so that is can be adjusted or removed, without operative intervention, according to the patient's clinical course and growth.


Assuntos
Atresia Esofágica/cirurgia , Junção Esofagogástrica/cirurgia , Fístula Traqueoesofágica/cirurgia , Emergências , Humanos , Recém-Nascido , Ligadura/instrumentação , Ligadura/métodos , Elastômeros de Silicone
8.
Ann Thorac Surg ; 61(3): 992-3, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8619735

RESUMO

This case report demonstrates the utility of transesophageal echocardiography in the rapid diagnosis of cardiac injury from blunt thoracic trauma. Initial transesophageal echocardiography identified a flail tricuspid valve leaflet and regurgitation in a patient with jugular venous distention and hemodynamic instability. Progressive hypoxemia prompted repeat transesophageal echocardiography with contrast enhancement, which revealed opening of the foramen ovale and a right-to-left interatrial shunt. Operative repair of the lesion was lifesaving.


Assuntos
Ecocardiografia Transesofagiana , Insuficiência da Valva Tricúspide/diagnóstico por imagem , Adulto , Cianose , Feminino , Traumatismos Cardíacos/complicações , Humanos , Insuficiência da Valva Tricúspide/etiologia , Insuficiência da Valva Tricúspide/cirurgia , Ferimentos não Penetrantes/complicações
9.
Urology ; 41(6): 579-81, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8516997

RESUMO

Bilateral shattered kidneys secondary to blunt abdominal trauma has not, to our knowledge, been reported. In the case reported herein, severe pulmonary, myocardial, and orthopedic injuries necessitated nonoperative management of this peculiar injury. The patient recovered without sequelae related to the renal injury.


Assuntos
Rim/lesões , Traumatismo Múltiplo , Ferimentos não Penetrantes/terapia , Adulto , Contraindicações , Humanos , Masculino , Procedimentos Cirúrgicos Operatórios
10.
Am Surg ; 61(3): 244-51, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7887539

RESUMO

The future of any specialty in medicine depends in large part on the career choices of its trainees. We obtained data from General Surgery Chief Residents who finished their training in 1990 and compared their attitudes to a similar survey conducted by us in 1985. According to those responses, residents in general surgery continue to choose fellowship training at a time when they no longer perceive an oversupply of general surgeons. This has broad implications for the future of general surgery as a specialty that requires significant change in the structure of our residency programs.


Assuntos
Atitude do Pessoal de Saúde , Escolha da Profissão , Cirurgia Geral/tendências , Internato e Residência , Medicina , Especialização , Feminino , Previsões , Cirurgia Geral/educação , Humanos , Masculino , Inquéritos e Questionários
11.
Am Surg ; 54(4): 195-9, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3355016

RESUMO

Diaphragmatic rupture following blunt torso trauma is an infrequent injury often posing a considerable diagnostic challenge. Between June 1984 and July 1986, nine patients sustaining rupture of the diaphragm due to blunt trauma were treated. All were injured in high-speed motor-vehicle accidents. Six patients arrived in shock (SBP less than or equal to 95 mm Hg). All patients had multiple associated injuries; mean ISS = 41.5. Eight patients (89%) had associated intra-abdominal injuries, the spleen being injured most frequently (63%). Associated thoracic injuries occurred in six patients (67%). The admission CXR was abnormal in eight patients (89%) but diagnostic of diaphragmatic rupture in only four. DPL was positive in four of five patients (80%) and falsely negative in one. Seven ruptures were left-sided, one right-sided and one involved the central tendon. All injuries were diagnosed shortly after admission and successfully repaired via a transabdominal approach. One patient died as a result of a massive subdural hematoma. Blunt diaphragmatic rupture is an indication of a high-energy insult and is usually associated with other major organ system injuries. An aggressive approach to the management of the multiply injured patient can result in early recognition and successful treatment of this injury.


Assuntos
Diafragma/lesões , Ferimentos não Penetrantes/cirurgia , Adolescente , Adulto , Idoso , Diafragma/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ruptura , Irrigação Terapêutica , Toracotomia , Ferimentos não Penetrantes/diagnóstico
12.
J Perinatol ; 7(1): 21-9, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-3507538

RESUMO

This paper introduces a ventilation management system for neonates. Its main feature is the manner in which it incorporates the clinician's decisions and the prediction of ventilator adjustments based upon actual patient data.


Assuntos
Respiração Artificial/métodos , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Prontuários Médicos , Microcomputadores , Software
13.
Phys Rev Lett ; 97(26): 261302, 2006 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-17280414

RESUMO

We propose a strategy for how to look for dark matter particles possessing a radiative decay channel and derive constraints on their parameters from observations of x rays from our own Galaxy and its dwarf satellites. When applied to sterile neutrinos in the keV mass range this approach gives a significant improvement to restrictions on neutrino parameters compared with previous works.

14.
Phys Rev Lett ; 95(9): 091301, 2005 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-16197203

RESUMO

We canonically quantize the dynamics of the brane universe embedded into the five-dimensional Schwarzschild-anti-de Sitter bulk space-time. We show that in the brane-world settings the formulation of the quantum cosmology, including the problem of initial conditions, is conceptually more simple than in the (3+1)-dimensional case. The Wheeler-DeWitt equation is a finite-difference equation. It is exactly solvable in the case of a flat universe and we find the ground state of the system. The closed brane universe can be created as a result of decay of the bulk black hole.

15.
J Math Biol ; 4(1): 35-47, 1977 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-845511

RESUMO

A continuous-time Markov chain model consisting of four positional and directional states is used to predict the eventual relative positioning of two motile cell types. It is assumed that the period of observation is small in comparison with the generation time of both cell types. The method is useful in predicting developmental phenomena and is applicable to complex patterns involving more than two types of cells.


Assuntos
Movimento Celular , Modelos Biológicos , Morfogênese , Indução Embrionária , Cadeias de Markov
16.
Invest Urol ; 13(5): 383-4, 1976 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1254432

RESUMO

Twelve New Zealand rabbits were studied for ureterovesical reflux. Dissections revealed the intramural ureter and ureterovesical junction to follow an upward and medial course, unlike the course observed in man. This course could not be altered or distorted by dissection of the bladder base or ureter, by freeing the urether retroperitoneally, or by changing the position of the animal.


Assuntos
Coelhos/anatomia & histologia , Ureter/anatomia & histologia , Bexiga Urinária/anatomia & histologia , Animais , Masculino
17.
IMA J Math Appl Med Biol ; 4(3): 201-5, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-3453375

RESUMO

In this paper, we find the pressure waveform that minimizes the work of distending the alveoli in the lungs while achieving the desired mean airway pressure and alveolar tidal volume. The model used takes into account the compliance of the airway. The main result is a formula for the pressure waveform at the mouth as a function of time and lung parameters.


Assuntos
Modelos Biológicos , Alvéolos Pulmonares/fisiologia , Respiração , Humanos , Matemática , Pressão
18.
Cancer Invest ; 9(5): 513-20, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1933484

RESUMO

Recent laboratory and clinical data suggest that some human neoplasms exhibit unusually high levels of cell-surface receptors for epidermal growth factor, and that this abnormality is associated with rapid cellular proliferation and poor prognosis. We propose that the existence of an abnormally high number of mitogen receptors is not merely correlated with rapid proliferation but is pathophysiologically responsible for such behavior. Cells with high levels of mitogen receptors may be rendered 'hypersensitive' to mitogenic stimuli, and hence may be stimulated to divide even when ambient mitogen concentrations are at a low 'background' level, insufficient to prompt the division of cells with a normal number of receptors. To investigate this hypothesis further, we have developed a mathematical model that describes proliferative behavior of cells as a function of mitogen concentration and receptor number. The model enables us to simulate the proliferative behavior of cells with various receptor levels at various mitogen concentrations and predicts a growth advantage associated with excess mitogen receptors. Computer simulations based on the model are consistent with previously published experimental data. This work provides support for the view that overexpression of genes encoding normal growth factor receptors can contribute to the inappropriate proliferation of neoplastic cells.


Assuntos
Receptores ErbB/análise , Modelos Biológicos , Neoplasias/patologia , Divisão Celular , Fator de Crescimento Epidérmico/análise , Fator de Crescimento Epidérmico/fisiologia , Receptores ErbB/fisiologia , Humanos , Neoplasias/química , Células Tumorais Cultivadas
19.
Exp Cell Biol ; 56(6): 289-96, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3224747

RESUMO

A method is presented for analysing the vectors of cells locomoting within three-dimensional collagen gels. The method detected differences in locomotory vector patterns between cells locomoting in two different gel formats. The potential of this analytical method for determining the role of the extracellular matrix in modulating cell locomotory behaviour is discussed.


Assuntos
Movimento Celular , Animais , Colágeno , Matriz Extracelular/fisiologia , Fibroblastos/citologia , Géis , Processamento de Imagem Assistida por Computador/métodos , Codorniz , Estatística como Assunto
20.
Can J Physiol Pharmacol ; 55(1): 1-6, 1977 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-843984

RESUMO

The locomotion of human neutrophils is modelled by a continuous-time Markov chain model consisting of five states: state O, where the cell is stationary, and four motile states whose directions are defined by the four quadrants of a Cartesian plane. In this paper, the Markov property is verified experimentally in special cases. Further experimental evidence for the model is provided by the waiting-time distributions in each of the five states, which are well approximated by exponential distributions. Using the steady-state distribution of the Markov chain as a measure of the ultimate motion of the cells, it is possible to detect the effect of known chemotactic agents upon neutrophil locomotion. Other useful parameters describing neutrophil locomotion are presented.


Assuntos
Quimiotaxia , Cadeias de Markov , Modelos Biológicos , Neutrófilos/fisiologia , Probabilidade , Movimento Celular , Humanos , Fatores de Tempo
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