RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
We present a study on the possibility of searching for long-lived supersymmetric partners with the MoEDAL experiment at the LHC. MoEDAL is sensitive to highly ionising objects such as magnetic monopoles or massive (meta)stable electrically charged particles. We focus on prospects of directly detecting long-lived sleptons in a phenomenologically realistic model which involves an intermediate neutral long-lived particle in the decay chain. This scenario is not yet excluded by the current data from ATLAS or CMS, and is compatible with astrophysical constraints. Using Monte Carlo simulation, we compare the sensitivities of MoEDAL versus ATLAS in scenarios where MoEDAL could provide discovery reach complementary to ATLAS and CMS, thanks to looser selection criteria combined with the virtual absence of background. It is also interesting to point out that, in such scenarios, in which charged staus are the main long-lived candidates, the relevant mass range for MoEDAL is compatible with a potential role of Supersymmetry in providing an explanation for the anomalous events observed by the ANITA detector.
RESUMO
A prospective study was made on 1068 pupils, aged between 10-15 years (group I). From this group 995 pupils were examined after four to seven years (group II). Their age was between 16-19 years. The study contained: anthropometric data, blood pressure (BP) and pulse measurements, and a standard record using the epidemiologic interview method. For each pupil we determined the following familial and personal antecedent of cardiovascular disease, especially arterial hypertension; alimentary habits (salt and hydro-carbonate excess); consumption of coffee and cigarettes; physical activity; tendency to sedentarism; school or family stress; and behaviour type. Data were worked out and interpreted, using epidemiologic and statistic methods in Epi Info 6 program. The prevalence of genetic factors (4% in group I and 4.3% in group II), consumption of salt (38% in group I and 35% in group II), obesity (1.5% in group and 1.4% in group II), sedentariness (4.8% in group I and 6.8% in group II), stress (9.8% in group I and 10.5% in group II), with behaviour type A (41% I group and 52% in group II) all presented almost equal values in the two groups regardless of age or BP level. The statistical study of the influence of the risk factors on BP values, using student's t test has demonstrated the contributory part of the genetic factor, the excess of sweets and stress. The deleterious effects of arterial hypertension risk factors, which can begin early in childhood demonstrate the necessity for responsible parties (family, school, doctors, etc.) to be aware of these risk factors and assist in their control.
Assuntos
Hipertensão/epidemiologia , Hipertensão/etiologia , Adolescente , Criança , Feminino , Humanos , Hipertensão/genética , Hipertensão/prevenção & controle , Estilo de Vida , Masculino , Fatores de Risco , Romênia/epidemiologia , Estresse Psicológico/complicaçõesRESUMO
Although intensively discussed and finally accepted in the last years "white coat phenomenon" (WCF) still raises the question of the benefit of diagnosing it in pediatric patients as its possible link with the subsequent essential hypertension is not clear yet. This study included 1068 schoolchildren (aged 10 to 16 years) submitted to a screening program for detecting the in time variations of blood pressure (BP). When the study was started WCP was present in 60 children (5.6%) and when it ended its frequency raised to 8.73%. In 14 of 60 children (23.3%) WCP progressed to borderline or confirmed essential hypertension, incidence higher that that of similar forms of essential hypertension occurring in patients with normal BP levels (20 of 955 = 2.05%). With time, the frequency of borderline and confirmed essential hypertension has also increased: 5.11% at the first determination to 7.85% at last one. The high frequency of WCF and associated with the high frequency of its progression to essential hypertension support the idea that WCP has a predictive value for the development of essential hypertension. An early diagnosis and the prevention of other risk factors may lower the frequency of essential hypertension in adults.
Assuntos
Hipertensão/psicologia , Adolescente , Envelhecimento/fisiologia , Pressão Sanguínea , Determinação da Pressão Arterial/estatística & dados numéricos , Criança , Humanos , Hipertensão/diagnóstico , Hipertensão/fisiopatologiaRESUMO
This investigation was aimed at emphasizing the importance of early detection and elimination of the favoring factors which associated with an adequate treatment of urinary tract infection (UTI) represent the only way to prevent the recurrences that with time might cause severe kidney dysfunctions. It is a retrospective study of 220 girls aged 1 month to 16 years referred in the interval 1993-1997 to Iasi Polyclinic No. 1 for pediatric gynecological examination and diagnosed with urinary tract infection. The clinical and laboratory evaluations were directed at determining the site of UTI, the factors that favored the recurrences, and the effects on renal function. The following favoring factors were found: disorders of the genital tract (22.2%), constipation (11.6%), oxyuriasis (4.5%), urinary tract obstructions (5.9%). The genital tract disorders were represented by inflammation (70%) (vaginitis, vulvovaginitis) and malformations (30%) (labia minora fusion, imperforate hymen, etc). The specific inflammation (48.5%) was mycotic (41.1%), bacterial (29.3%), the same pathogen being detected both in urine and vaginal discharge, trichomonal (17.6%), and gonococcal (11.6%). The high rate of recurrence in some UTI cases has proved once again the important role played by the favoring factors (genital tract disorders, urinary tract obstruction, constipation) and suggested that the correction of these conditions should be the only reasonable way to prevent recurrences.
Assuntos
Doenças dos Genitais Femininos/diagnóstico , Infecções Urinárias/diagnóstico , Adolescente , Distribuição por Idade , Criança , Pré-Escolar , Feminino , Doenças dos Genitais Femininos/complicações , Doenças dos Genitais Femininos/epidemiologia , Humanos , Lactente , Recidiva , Estudos Retrospectivos , Romênia/epidemiologia , Infecções Urinárias/epidemiologia , Infecções Urinárias/etiologiaRESUMO
UNLABELLED: The aim of the study was to investigate the main morphofunctional aspects of the cardiac involvement in systemic hypertension in child. METHODS: 48 children with aged ranging between 2 months-18 years, diagnosed with systemic hypertension (SH), were followed up more than 1 year (with treatment) and investigated by clinical examination and noninvasive methods. The etiology of SH was: * secondary SH (40 cases): acute (8) and chronic nephropathy (20), 13 cases being dialysed; coarctation of aorta (10) and pheochromocytoma (2 cases) and * essential SH (8 cases): "borderline" type and also confirmed. RESULTS: The echocardiographic findings had a superior sensibility to ECG and chest X-ray findings, concerning cardiac involvement in SH, especially in the secondary forms, with high values of systolic and/or diastolic blood pressure and with a long period of evolution: hypertrophy of the left ventricle (LV) (31 cases = 65%) with septal predominance (10); * alteration of diastolic function of LV (11), but with normal systolic function of LV (all the cases). These changes have not been observed in acute nephropathy or they were unsignificant in essential SH. Repeated echocardiography after minimum 6 months proved a varied regression of hypertrophy of LV and improved diastolic function of LV in children who received antihypertensive therapy, including spironolactone and/or angiotensin converting enzyme inhibitors. CONCLUSION: Because such cardiac involvement are important and of greater risk factor for the hypertensive patients, the early diagnosis by echocardiography, the follow up of the evolution and the diminish of cardiac disorders by the treatment mentioned above, may improve the prognosis of the disease.
Assuntos
Coração/fisiopatologia , Hipertensão/fisiopatologia , Adolescente , Criança , Pré-Escolar , Ecocardiografia , Eletrocardiografia , Humanos , Hipertensão/diagnóstico por imagem , Hipertensão/etiologia , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/fisiopatologia , LactenteRESUMO
Out of 205 children, former patients with viral hepatitis, investigated after the end of the follow-up period by clinical and laboratory examinations, 9 (4.4%) presented mild or moderate pathological alterations. At the second control, carried out after an another interval de 1-1½ years, the pathological alterations were refound only in 2 of the former patients, suggesting that all the others presented lasting forms of acute viral hepatitis evolving towards healing. The presence of AgHBs and the alteration of proteinogramme in the acute phase of VH can serve as criteria of unfavourable prognosis of the disease evolution and impose a preferential follow-up of this category of patients.