Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 49
Filtrar
1.
Sci Rep ; 14(1): 1224, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38216583

RESUMO

RadioLab is an Italian project, addressed to school-age people, and designed for the dissemination of scientific culture on the theme of environmental radioactivity, with particular regards to the importance of knowledge of radon gas exposure. The project is a nationwide initiative promoted by the National Institute of Nuclear Physics- INFN. First tool used by the project, and of immediate impact to assess the public awareness on radon, is the administration of the survey "do you know the radon gas?". In the survey, together with the knowledge of radon and of its sources, information on personal, cultural and territorial details regarding the interviewees are also taken. Reasonably, the survey invests not only young people, but also their relatives, school workers and, gradually, the public. The survey is administrated during exhibitions or outreach events devoted to schools, but also open to the public. The survey is in dual form: printed and online. The online mode clearly leads RadioLab project even outside the school environment. Based on the results of the survey, several statistical analyses have been performed and many conclusions are drawn about the knowledge of the population on the radon risk. The RadioLab benefit and the requirement to carry on the project goals, spreading awareness of environmental radioactivity from radon, emerge. The dataset involves all twenty Italian regions and consists of 28,612 entries covering the 5-year period 2018-2022.

2.
Phys Rev Lett ; 131(14): 142501, 2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37862664

RESUMO

We present the measurement of the two-neutrino double-ß decay rate of ^{76}Ge performed with the GERDA Phase II experiment. With a subset of the entire GERDA exposure, 11.8 kg yr, the half-life of the process has been determined: T_{1/2}^{2ν}=(2.022±0.018_{stat}±0.038_{syst})×10^{21} yr. This is the most precise determination of the ^{76}Ge two-neutrino double-ß decay half-life and one of the most precise measurements of a double-ß decay process. The relevant nuclear matrix element can be extracted: M_{eff}^{2ν}=(0.101±0.001).

3.
Eur Phys J C Part Fields ; 83(9): 778, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37674593

RESUMO

We search for tri-nucleon decays of 76Ge in the dataset from the GERmanium Detector Array (GERDA) experiment. Decays that populate excited levels of the daughter nucleus above the threshold for particle emission lead to disintegration and are not considered. The ppp-, ppn-, and pnn-decays lead to 73Cu, 73Zn, and 73Ga nuclei, respectively. These nuclei are unstable and eventually proceed by the beta decay of 73Ga to 73Ge (stable). We search for the 73Ga decay exploiting the fact that it dominantly populates the 66.7 keV 73mGa state with half-life of 0.5 s. The nnn-decays of 76Ge that proceed via 73mGe are also included in our analysis. We find no signal candidate and place a limit on the sum of the decay widths of the inclusive tri-nucleon decays that corresponds to a lower lifetime limit of 1.2×1026 yr  (90% credible interval). This result improves previous limits for tri-nucleon decays by one to three orders of magnitude.

4.
Eur Phys J C Part Fields ; 83(4): 319, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37122826

RESUMO

The ability to detect liquid argon scintillation light from within a densely packed high-purity germanium detector array allowed the Gerda experiment to reach an exceptionally low background rate in the search for neutrinoless double beta decay of 76 Ge. Proper modeling of the light propagation throughout the experimental setup, from any origin in the liquid argon volume to its eventual detection by the novel light read-out system, provides insight into the rejection capability and is a necessary ingredient to obtain robust background predictions. In this paper, we present a model of the Gerda liquid argon veto, as obtained by Monte Carlo simulations and constrained by calibration data, and highlight its application for background decomposition.

6.
Eur Phys J C Part Fields ; 82(4): 284, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35464994

RESUMO

The GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double- ß decay in 76 Ge using isotopically enriched high purity germanium detectors at the Laboratori Nazionali del Gran Sasso of INFN. After Phase I (2011-2013), the experiment benefited from several upgrades, including an additional active veto based on LAr instrumentation and a significant increase of mass by point-contact germanium detectors that improved the half-life sensitivity of Phase II (2015-2019) by an order of magnitude. At the core of the background mitigation strategy, the analysis of the time profile of individual pulses provides a powerful topological discrimination of signal-like and background-like events. Data from regular 228 Th calibrations and physics data were both considered in the evaluation of the pulse shape discrimination performance. In this work, we describe the various methods applied to the data collected in Gerda Phase II corresponding to an exposure of 103.7 kg year. These methods suppress the background by a factor of about 5 in the region of interest around Q ß ß = 2039  keV, while preserving ( 81 ± 3 ) % of the signal. In addition, an exhaustive list of parameters is provided which were used in the final data analysis.

7.
Eur Phys J C Part Fields ; 81(6): 505, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34720720

RESUMO

Neutrinoless double- ß decay of 76 Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in 76 Ge. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the Gerda setup. The measured resolutions at the Q-value for double- ß decay of 76 Ge ( Q ß ß  = 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (Gerda) experiment and an accumulated exposure of 8.5 kg · year, the background index after analysis cuts is measured to be 4 . 9 - 3.4 + 7.3 × 10 - 4 counts / ( keV · kg · year ) around Q ß ß . This work confirms the feasibility of IC detectors for the next-generation experiment Legend.

8.
Eur Phys J C Part Fields ; 81(8): 682, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34776783

RESUMO

The GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double- ß decay in 76 Ge with an array of about 40 high-purity isotopically-enriched germanium detectors. The experimental signature of the decay is a monoenergetic signal at Q ß ß = 2039.061 ( 7 )  keV in the measured summed energy spectrum of the two emitted electrons. Both the energy reconstruction and resolution of the germanium detectors are crucial to separate a potential signal from various backgrounds, such as neutrino-accompanied double- ß decays allowed by the Standard Model. The energy resolution and stability were determined and monitored as a function of time using data from regular 228 Th calibrations. In this work, we describe the calibration process and associated data analysis of the full Gerda dataset, tailored to preserve the excellent resolution of the individual germanium detectors when combining data over several years.

9.
Orthopade ; 50(6): 425-434, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33185695

RESUMO

BACKGROUND: Bowel dysfunction after spinal surgery is often underestimated and if not treated in a timely manner can lead to undesirable surgical interventions or fatal complications. The current medical literature primarily focuses on bowel dysfunction as a result of spinal injury. OBJECTIVE: The purpose of this review is to explore this topic in evaluating current evidence regarding the causes of acute bowel dysfunction after elective spinal surgery, primarily the thoracolumbar spine. Since available evidence for recommendations of treatment is scarce, an interdisciplinary management approach for treatment of bowel dysfunction following spinal surgery is also formulated. MATERIAL AND METHODS: An extensive literature search was carried out on PubMed. Keywords that were used in the search included bowel dysfunction, obstruction, postoperative ileus, spinal surgery, spinal fusion, constipation, opioid-induced constipation, colonic pseudo-obstruction, ischemic colitis, immobility-induced bowel changes, epidural anesthesia and diet. Relevant studies were chosen and included in the review. The treatment approach used in the spine center of a university hospital was included. RESULTS: Current research mainly focuses on investigating the nature and symptomatology of chronic bowel dysfunction after spinal cord injury. Emphasis on the acute phase of bowel dysfunction in patients after elective spinal surgery is lacking. The comorbidities that exacerbate bowel dysfunction postoperatively are well-defined. There has been refinement and expansion of the pharmacological and nonpharmacological treatment that could be implemented. Enough evidence exists to provide sufficient care. CONCLUSION: Management of acute bowel dysfunction after spinal surgery requires a comprehensive and individualized approach, encompassing comorbidities, behavioral changes, medications and surgery. Close supervision and timely treatment could minimize further complications. Research is required to identify patients who are at a higher risk of developing bowel dysfunction after specific spinal procedures.


Assuntos
Analgésicos Opioides , Traumatismos da Medula Espinal , Constipação Intestinal , Procedimentos Cirúrgicos Eletivos , Hospitais , Humanos
11.
Phys Rev Lett ; 125(1): 011801, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32678643

RESUMO

We present the first search for bosonic superweakly interacting massive particles (super-WIMPs) as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-ß decay experiment which operates high-purity germanium detectors enriched in ^{76}Ge in an ultralow background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV/c^{2} to 1 MeV/c^{2}. No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV/c^{2} have been set. As an example, at a mass of 150 keV/c^{2} the most stringent direct limits on the dimensionless couplings of axionlike particles and dark photons to electrons of g_{ae}<3×10^{-12} and α^{'}/α<6.5×10^{-24} at 90% credible interval, respectively, were obtained.

12.
Phys Rev Lett ; 125(25): 252502, 2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33416389

RESUMO

The GERmanium Detector Array (GERDA) experiment searched for the lepton-number-violating neutrinoless double-ß (0νßß) decay of ^{76}Ge, whose discovery would have far-reaching implications in cosmology and particle physics. By operating bare germanium diodes, enriched in ^{76}Ge, in an active liquid argon shield, GERDA achieved an unprecedently low background index of 5.2×10^{-4} counts/(keV kg yr) in the signal region and met the design goal to collect an exposure of 100 kg yr in a background-free regime. When combined with the result of Phase I, no signal is observed after 127.2 kg yr of total exposure. A limit on the half-life of 0νßß decay in ^{76}Ge is set at T_{1/2}>1.8×10^{26} yr at 90% C.L., which coincides with the sensitivity assuming no signal.

13.
Orthopade ; 49(11): 1000-1005, 2020 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-31811321

RESUMO

BACKGROUND: The sacroiliac joint is a common cause of low back pain. Due to variable symptoms, the diagnosis is often very difficult. For diagnosis, systemic disease, as well as pathologies in the hips and lumbar spine must be excluded. OBJECTIVES: To describe anatomy and function of the joint and underlying pathologies. To present the evidence of actual diagnostic and therapeutic options. MATERIALS AND METHODS: An extensive literature research was carried out on PubMed. RESULTS: The sacroiliac joint is an important and biomechanically complex joint. There are many controversial diagnostic tests to identify the sacroiliac joint as a source of pain. The cause of the dysfunction must be identified in order to treat it correctly and to prevent a chronification of the pain. The gold standard is conservative care. CONCLUSION: The sacroiliac joint must be included in the differential diagnosis in patients with low back pain. Diagnostic tests are often insufficient for the diagnosis of sacroiliac joint pain. Many of the current diagnostic and therapeutic options present weak evidence.


Assuntos
Artralgia/etiologia , Dor Lombar , Articulação Sacroilíaca , Artralgia/diagnóstico , Humanos , Dor Lombar/diagnóstico , Dor Lombar/etiologia , Dor Lombar/patologia , Vértebras Lombares , Articulação Sacroilíaca/anatomia & histologia , Articulação Sacroilíaca/diagnóstico por imagem , Articulação Sacroilíaca/fisiologia
14.
Eur Phys J C Part Fields ; 79(11): 978, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31885491

RESUMO

The GERmanium Detector Array (Gerda) is a low background experiment located at the Laboratori Nazionali del Gran Sasso in Italy, which searches for neutrinoless double-beta decay of 76 Ge into 76 Se+2e - . Gerda has been conceived in two phases. Phase II, which started in December 2015, features several novelties including 30 new 76Ge enriched detectors. These were manufactured according to the Broad Energy Germanium (BEGe) detector design that has a better background discrimination capability and energy resolution compared to formerly widely-used types. Prior to their installation, the new BEGe detectors were mounted in vacuum cryostats and characterized in detail in the Hades underground laboratory in Belgium. This paper describes the properties and the overall performance of these detectors during operation in vacuum. The characterization campaign provided not only direct input for Gerda Phase II data collection and analyses, but also allowed to study detector phenomena, detector correlations as well as to test the accuracy of pulse shape simulation codes.

15.
Science ; 365(6460): 1445-1448, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31488705

RESUMO

A discovery that neutrinos are Majorana fermions would have profound implications for particle physics and cosmology. The Majorana character of neutrinos would make possible the neutrinoless double-ß (0νßß) decay, a matter-creating process without the balancing emission of antimatter. The GERDA Collaboration searches for the 0νßß decay of 76Ge by operating bare germanium detectors in an active liquid argon shield. With a total exposure of 82.4 kg⋅year, we observe no signal and derive a lower half-life limit of T 1/2 > 0.9 × 1026 years (90% C.L.). Our T 1/2 sensitivity, assuming no signal, is 1.1 × 1026 years. Combining the latter with those from other 0νßß decay searches yields a sensitivity to the effective Majorana neutrino mass of 0.07 to 0.16 electron volts.

16.
Orthopade ; 47(11): 960-961, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30267122

RESUMO

Erratum to: Orthopäde 2018 https://doi.org/10.1007/s00132-018-3631-7 Dear Reader,Unfortunately, an incorrect subtitle was published in the online version of the article.We kindly ask you to use the correct title:"Magnetically controlled growing rods for rigid scoliosis.An alternative to halo-gravity ….

17.
Orthopade ; 47(10): 867-870, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30194629

RESUMO

The treatment concept for severe rigid idiopathic scoliosis is a short-term application of halo-gravity traction to enable maximum correction and subsequent dorsal fusion. The method has already been mentioned in the literature as an effective procedure. This case report demonstrates the use of a new treatment concept using magnetically controlled distraction rods as a possible alternative to the halo-gravity traction device. To our knowledge the use of this technique in severe rigid idiopathic scoliosis has not yet been published.


Assuntos
Magnetismo , Escoliose , Fusão Vertebral , Tração , Adolescente , Feminino , Humanos , Cuidados Pré-Operatórios , Estudos Retrospectivos , Escoliose/terapia
18.
Phys Rev Lett ; 120(13): 132503, 2018 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-29694176

RESUMO

The GERDA experiment searches for the lepton-number-violating neutrinoless double-ß decay of ^{76}Ge (^{76}Ge→^{76}Se+2e^{-}) operating bare Ge diodes with an enriched ^{76}Ge fraction in liquid argon. The exposure for broad-energy germanium type (BEGe) detectors is increased threefold with respect to our previous data release. The BEGe detectors feature an excellent background suppression from the analysis of the time profile of the detector signals. In the analysis window a background level of 1.0_{-0.4}^{+0.6}×10^{-3} counts/(keV kg yr) has been achieved; if normalized to the energy resolution this is the lowest ever achieved in any 0νßß experiment. No signal is observed and a new 90% C.L. lower limit for the half-life of 8.0×10^{25} yr is placed when combining with our previous data. The expected median sensitivity assuming no signal is 5.8×10^{25} yr.

19.
Orthopade ; 47(4): 335-340, 2018 04.
Artigo em Alemão | MEDLINE | ID: mdl-29546442

RESUMO

BACKGROUND: In the light of the increasingly aging population and the widespread understanding of the sagittal profile of symptomatic patients with adult spinal deformity (ASD), pervasive utilization of osteotomies on the vertebral column should be expected. These surgeries are accompanied with relatively high complication rates. However, there is no uniform definition or classification in terms of grading the severity or chronological incidence of complications after ASD surgery. OBJECTIVES: The aim of this work is to give an overview of the different classifications described in the literature hitherto and to propose a standardized, clinically utile classification of complications after ASD surgery. Finally, the aim is to illustrate this classification using two case examples. MATERIALS AND METHODS: We conducted a systematic PubMed search with the keywords: "adult spinal deformity", "surgery", "complications" and "classification". Results were screened by title, abstract and full-text article. RESULTS: 22 articles were included in this review. Regarding the systematic classification of the severity of a complication, the CTCAE classification (Common Terminology Criteria for Adverse Events v4.0) is a validated and well-established severity stratification tool used in oncologic treatment. Regarding chronological occurrence, complications can be categorized into three phases: intra-operative, peri-operative and post-operative. DISCUSSION: The time of occurrence of a certain complication and its severity should constitute the cornerstones of a standardized and practical classification of complications after ASD surgery. To enable uniform reporting and coherent documentation of complications, spine surgeons should find consensus on a standardized classification. Future work needs to be directed towards defining and conducting an individual pre-operative risk stratification of adult spine deformity surgical candidates leading to a possible mitigation of surgery-related complications.


Assuntos
Osteotomia , Doenças da Coluna Vertebral , Coluna Vertebral , Adulto , Idoso , Humanos , Incidência , Estudos Retrospectivos , Doenças da Coluna Vertebral/classificação , Doenças da Coluna Vertebral/cirurgia , Coluna Vertebral/patologia , Coluna Vertebral/cirurgia
20.
Appl Radiat Isot ; 87: 331-5, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24331853

RESUMO

The dead-layer uniformity of the top surface of two high purity germanium detectors has been studied using a novel automated scanning set-up that allows a fine-grained topography of a detector's top and lateral surfaces. Comparisons between measurements and Monte Carlo simulations allowed implementation of a dead-layer variation into the detector model, which reproduces the measurements results. The effect of the non-uniform dead-layer on activity determinations based on low-energy γ-rays (i.e. below ~100 keV) has been determined to be of the order of 10% or more.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...