2,866 research outputs found

    Scattering polarization of hydrogen lines in the presence of turbulent electric fields

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    We study the broadband polarization of hydrogen lines produced by scattering of radiation, in the presence of isotropic electric fields. In this paper, we focus on two distinct problems: a) the possibility of detecting the presence of turbulent electric fields by polarimetric methods, and b) the influence of such fields on the polarization due to a macroscopic, deterministic magnetic field. We found that isotropic electric fields decrease the degree of linear polarization in the scattered radiation, with respect to the zero-field case. On the other hand, a distribution of isotropic electric fields superimposed onto a deterministic magnetic field can generate a significant increase of the degree of magnetic-induced, net circular polarization. This phenomenon has important implications for the diagnostics of magnetic fields in plasmas using hydrogen lines, because of the ubiquitous presence of the Holtsmark, microscopic electric field from neighbouring ions. In particular, previous solar magnetographic studies of the Balmer lines of hydrogen may need to be revised because they neglected the effect of turbulent electric fields on the polarization signals. In this work, we give explicit results for the Lyman-alpha and Balmer-alpha lines.Comment: 15 pages, 6 figure

    Growth of out-of-plane standing MoTe2(1-x)Se2x/MoSe2 composite flake films by sol–gel nucleation of MoOy and isothermal closed space telluro-selenization

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    This study describes the sol–gel processing of MoOy on Si (1 0 0) to subsequently achieve out-of-plane MoTe2/MoSe2 flake composite films by an isothermal closed space vapor transformation. The oxide precursor films have been prepared from a Mo isopropoxide solution in isopropanol and acid catalysis induced by HCl. Thermal annealing at 200, 400 and 600 °C enhanced the condensation after xerogel formation. An x-ray absorption analysis demonstrates that films condensed at 200 °C are at an intermediate chemical state between MoO3 and MoO2. To achieve MoTe2/MoSe2 composite films, the precursor oxide films were reduced in H2 and exposed to the chalcogenides by isothermal closed space vapor transport at 600 °C. The multilayered nanocomposite films grow with an out-of-plane flake-like structure and an evident integration of Se in the MoTe2 phase according to a MoTe2(1-x)Se2x alloy, with an estimation of x of 0.25. The alloy and the orientation of the flakes are consistent with the bands present in the Raman spectrum. These films are attractive for applications requiring high surface area interfaces favoring gas or ion exchange reactions with transition metal dichalcogenidesThe current research was funded by grant CTQ2017-84309-C2-2-R from Ministerio de Ciencia e Innovación (Spain). The authors acknowledge the ESRF and the Ministerio de Ciencia, Innovación y Universidades (Spain), for provision of synchrotron radiation facilities and the Consejo Superior de Investigaciones Científicas (Spain) financial support for the operation of the beamline under Grant No. PIE 2010 6 OE 01

    Towards elimination of measles and rubella in Italy. Progress and challenges

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    Introduction In the WHO European Region, endemic transmission of measles and rubella had been interrupted by 37 and 42 of the 53 member states (MSs), respectively, by 2018. Sixteen MSs are still endemic for measles, 11 for rubella and nine for both diseases, the latter including Italy. Elimination is documented by each country’s National Verification Committee (NVC) through an annual status update (ASU). Objective By analysing data used to produce the ASUs, we aimed to describe the advances made by Italy towards elimination of measles and rubella. Moreover, we propose a set of major interventions that could facilitate the elimination process. Methods A total of 28 indicators were identified within the six core sections of the ASU form and these were evaluated for the period 2013–2018. These indicators relate to the incidence of measles/rubella; epidemiological investigation of cases; investigation of outbreaks; performance of the surveillance system; population immunity levels; and implementation of supplemental immunization activities (SIAs). Results From 2013 to 2018, epidemiological and laboratory analyses of measles cases in Italy improved substantially, allowing timely investigation in 2017 and 2018 of most outbreak and sporadic cases and identification of the majority of genotypic variants. Moreover, since 2017, vaccination coverage has increased significantly. Despite these improvements, several areas of concern emerged, prompting the following recommendations: i) improve outbreak monitoring; ii) strengthen the MoRoNet network; iii) increase the number of SIAs; iv) reinforce vaccination services; v) maintain regional monitoring; vi) design effective communication strategies; vii) foster the role of general practitioners and family paediatricians. Conclusions The review of national ASUs is a crucial step to provide the NVC with useful insights into the elimination process and to guide the development of targeted interventions. Against this background, the seven recommendations proposed by the NVC have been shared with the Italian Ministry of Health and the Technical Advisory Group on measles and rubella elimination and have been incorporated into the new Italian Elimination Plan 2019–2023 as a technical aid to facilitate the achievement of disease elimination goals

    Evolution of occupational asthma: Does cessation of exposure really improve prognosis?

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    SummaryAimTo assess the evolution of occupational asthma (OA) depending on whether the patient avoids or continues with exposure to the offending agent.MethodsStudy in patients diagnosed with OA using a specific inhalation challenge. Patients underwent the following examinations on the same day: clinical interview, physical examination, forced spirometry, methacholine test and determination of total IgE. Clinical improvement, deterioration or no change were defined according to the changes seen on the GINA severity scale at the time of diagnosis.ResultsOf the 73 patients finally included, 55 had totally ended exposure and 18 continued to be exposed at work. Clinical improvement was observed in 47% of those who had terminated exposure and in 22% of those who remained exposed; clinical deterioration was observed in 14% and 17% respectively (p = 0.805). Logistical regression analysis, including the type of agent and the persistence or avoidance of exposure among the variables, did not show any predictive factors of clinical evolution. Similarly, the changes in FEV1 and in bronchial hyperresponsiveness were not associated with the avoidance or continuation of exposure to the causative agent.ConclusionsAvoiding exposure to the causative agent in patients with OA does not seem to improve prognosis in this disease. Despite these findings, there is insufficient evidence to recommend a change in current management guidelines

    Métodos para la limpieza física, química y biológica de las fábricas de piedra de monumentos históricas. El caso de San Lorenzo del Real de Burgos

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    The restoration process of historic stone-masonry monuments is described in this article. The intervention has to be conducted according to the specific character of the monument while recovering its original appearance. The restoration process of the principal facade of the Church of San Lorenzo el Real, Burgos (Spain) is described in this article, as an example of a historical monument located in an urban environment. In the first place, the history was researched and a compilation was made of all the extant documentation on its constructive evolution and the nature of its materials. We characterized the different types of limestone and we analyzed the mortar bonds in the masonry. Once the characteristics and the properties of the materials were known and their degree of decay, cleaning techniques were selected. The programme of work successfully renovated the church building, through the restoration of its main façade.El presente artículo muestra el proceso de restauración de las fábricas de piedra en monumentos históricos. La intervención tiene que llevarse a cabo de acuerdo a la personalidad del monumento, recuperando su aspecto original. En este artículo se describe el proceso de restauración de la fachada principal de la Iglesia de San Lorenzo el Real en Burgos (España), como un ejemplo de monumento histórico situado en ambientes urbanos. En primer lugar, se realiza una investigación histórica y se recopila toda la documentación existente tanto de su evolución constructiva como de la naturaleza de sus materiales. Caracterizamos las diferentes variedades de piedra caliza y analizamos los morteros de juntas de las fábricas de piedra. Una vez conocidas las características y propiedades de los materiales y su grado de deterioro, se establecen los métodos de limpieza a utilizar. Las actuaciones realizadas han conseguido recuperar el monumento, con la restauración de la fachada principal

    Scattering polarization of hydrogen lines from electric-induced atomic alignment

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    We consider a gas of hydrogen atoms illuminated by a broadband, unpolarized radiation with zero anisotropy. In the absence of external fields, the atomic J-levels are thus isotropically populated. While this condition persists in the presence of a magnetic field, we show instead that electric fields can induce the alignment of those levels. We also show that this electric alignment cannot occur in a two-term model of hydrogen (e.g., if only the Ly-alpha transition is excited), or if the level populations are distributed according to Boltzmann's law.Comment: 10 pages, 4 figures. Accepted by J.Phys.B: At.Mol.Opt.Phy

    An 18-year-old woman with a 34-cm metaplastic breast carcinoma

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    Metaplastic breast carcinomas (MBCs) are rare malignancies usually with poor prognosis. We report a case of an 18-year-old African female patient who presented with a 34-cm tumor on the right breast. Biopsy showed an extensively necrotic MBC negative for estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 (triple negative). A modified right radical mastectomy was performed, followed by adjuvant chemotherapy. Histology confirmed a widely necrotic undifferentiated malignant tumor, with strong and diffuse expression of vimentin and B-cell lymphoma 2, focal high-molecular-weight keratins and focal CD34 expression; Ki67 was >90%. There was no skin, deep margin or lymph node involvement. Six months after surgery, the patient showed a 9 × 7 cm nodule adjacent to the suture and adherent to the anterior chest wall. The tumor was considered unresectable and the patient evolved with rapid systemic deterioration. The patient had a progression-free survival of 6 months and overall survival of 9 months

    Duodeno-colic fistula as a rare presentation of lung cancer - surgical treatment of a stage IV oligometastatic lung disease

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    INTRODUCTION: Rare adenosquamous carcinomas have no defined standard approach given their low incidence. They present with nonspecific imaging characteristics and are described as having worse prognosis than other lung malignancies, with greater likelihood of local invasion and early metastasis. PRESENTATION OF CASE: Male caucasian patient, 43 years, 26 pack-year smoking history, presented with watery diarrhea, early emesis and loss of 25% body weight (20kg) in four weeks. Colonoscopy identified a left colonic mass. Abdominal CT/ultrasound showed a large fistulous lesion between the 4th portion of the duodenum and left colon. CT showed a solid mass in the right upper lung lobe. Endoscopy and transthoracic biopsy were inconclusive. En bloc D3 and D4 duodenectomy, proximal enterectomy and left hemicolectomy were performed, with inconclusive histology of the specimen. Three months later, a right upper lung lobectomy with lymphadenectomy was performed, revealing an adenosquamous carcinoma of lung origin, R0, staged as pT2pN0pM1b. Six months later, a single dural metastasis in the left cerebellopontine angle was detected and resected, with subsequent holocranial radiotherapy and systemic adjuvant chemotherapy. Patient is currently with 18 months follow-up, in good general health and with no evidence of recurrent disease. DISCUSSION: There are no specific guidelines to treat oligometastatic adenosquamous lung carcinoma. Our approach was abdominal surgery as a life-saving procedure and, months later, oncological resection of primary lung tumor and metachronous metastasis to the brain. CONCLUSION: A systematic, patient-oriented, patient-shared, multidisciplinary approach is particularly relevant when dealing with atypical presentations of rare diseases in young patients

    Avaliação das propriedades físico hídricas do solo em um programa de pagamento por serviços ambientais: Produtores de Água e Floresta sub-bacia do rio Sacra Família (RJ).

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    O presente trabalho busca através de análises laboratoriais estimar o grau de impacto do restauro florestal promovido pelo Produtores de Água e Floresta na sub-bacia do rio Sacra Família (RJ) comparando resultados após um ano de estabelecimento dos plantios sobre propriedades físico hídricas do solo, como: a textura, densidade de partículas, densidade do solo, porosidade e a estabilidade de agregados
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