157 research outputs found

    Determinant-Gravity: Cosmological implications

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    We analyze the action d4xdetBgμν+CRμν\int d^4x \sqrt{\det||{\cal B} g_{\mu\nu}+ {\cal C} R_{\mu\nu}}|| as a possible alternative or addition to the Einstein gravity. Choosing a particular form of B(R)=R{\cal B}(R)= \sqrt {R} we can restore the Einstein gravity and, if B=m2{\cal B}=m^2, we obtain the cosmological constant term. Taking B=m2+B1R{\cal B} = m^2 + {\cal B}_1 R and expanding the action in 1/m2 1/m^2, we obtain as a leading term the Einstein Lagrangian with a cosmological constant proportional to m4m^4 and a series of higher order operators. In general case of non-vanishing B{\cal B} and C{\cal C} new cosmological solutions for the Robertson-Walker metric are obtained.Comment: revtex format, 5 pages,8 figures,references adde

    A study of the bound states for square potential wells with position-dependent mass

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    A square potential well with position-dependent mass is studied for bound states. Applying appropriate matching conditions, a transcendental equation is derived for the energy eigenvalues. Numerical results are presented graphically and the variation of the energy of the bound states are calculated as a function of the well-width and mass.Comment: To appear in Phys. Lett. A (Present e-mail of A.G: [email protected]

    Intertwining technique for the one-dimensional stationary Dirac equation

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    The technique of differential intertwining operators (or Darboux transformation operators) is systematically applied to the one-dimensional Dirac equation. The following aspects are investigated: factorization of a polynomial of Dirac Hamiltonians, quadratic supersymmetry, closed extension of transformation operators, chains of transformations, and finally particular cases of pseudoscalar and scalar potentials. The method is widely illustrated by numerous examples

    Observed photodetachment in parallel electric and magnetic fields

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    We investigate photodetachment from negative ions in a homogeneous 1.0-T magnetic field and a parallel electric field of approximately 10 V/cm. A theoretical model for detachment in combined fields is presented. Calculations show that a field of 10 V/cm or more should considerably diminish the Landau structure in the detachment cross section. The ions are produced and stored in a Penning ion trap and illuminated by a single-mode dye laser. We present preliminary results for detachment from S- showing qualitative agreement with the model. Future directions of the work are also discussed.Comment: Nine pages, five figures, minor revisions showing final publicatio

    EP05.02-003 Durvalumab after Chemoradiotherapy (CRT) in Unresectable Stage III NSCLC. Comparative Study of Two Cohorts in the Real-World Setting

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    [EN] Introduction: Durvalumab is the new standard of care for unresectable locally advanced NSCLC, with PD-L1 _1% and who did not have progression after CRT treatment in the European Union. Our study compares the effectiveness and the frequency of radiation pneumonitis in patients treated with concurrent CRT with or without durvalumab consolidation during the same period in real clinical practice. Methods: A single-center retrospective study. 71 treated patients with unresectable stage III NSCLC were included between March 2018 and December 2021, 37 with CRT followed by durvalumab and 34 with CRT alone. Real-world progression-free survival (rwPFS) and real-world overall survival (rwOS) were calculated since the date of the end CRT. Propensity score matching (PSM) 1:1 was used to account for differences in baseline characteristics. Results: Median age was 67 years (range 46-82). 25.4% of the patients were _75 years old. 78.9% were men and 53.5% former smokers. 54.9% had squamous histology and 28%, 51% and 21% stage IIIA, IIIB and IIIC disease, respectively. The most used scheme was carboplatinpaclitaxel (43.7%), receiving induction chemotherapy in up to 54.9% of patients. 73.2% received between 60-66 Gy doses of radiotherapy. Median time from end of CRT to onset durvalumab was 44 days (range 13-120) with a median of 14 infusions (range 6-27). Of the 34 patients without durvalumab treatment, the expression PD-L1 <1% (58.8%) was the most frequent cause for rejecting consolidation therapy. After PSM analysis, patients distributions were well balanced. With a median follow-up of 19.7 months (range 1.4-36.6); median rw-PFS was 9.3 months (95% CI, 5-13.5) without durvalumab and 17 months (95% CI, 11-22.9) with durvalumab (p¼0.013). Median rw-OS was 19.3 months (95% CI, 3.8-34.8) without durvalumab and 29.9 months (95% CI, 23.3-36.6) with durvalumab (p¼0.241) with a rw-OS% at 6, 18 and 24 months of 90%, 62% and 49% vs 100%, 86% and 74%, respectively. The rate of radiation pneumonitis was more frequent with durvalumab consolidation (56.8% against 44.1%), (p¼0.346), especially within 3 months after CRT. G3 pneumonitis was only observed in the consolidation therapy. Conclusions: Our results demonstrate the effectiveness of durvalumab consolidation after CRT in real-world patients with unresectable stage III NSCLC. Further sample and longer follow-up are required to obtain more accurate results. Active surveillance and appropriate management for radiation pneumonitis are needed, in especially in candidates for consolidation treatmentS

    EP05.02-002 Who Benefits More of Durvalumab after Chemoradiotherapy (CRT) in Real-World Patients with Locally Advanced Non-Small-Cell Lung Cancer (NSCLC)?

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    [EN] Introduction: Durvalumab received EMA approval as consolidation therapy (CT) for unresectable stage III NSCLC with PD-L1 _1% and who did not have progression after CRT. Our objective was to analyze in real clinical practice the effectiveness of durvalumab and explore the clinical factors that may be associated with the benefit from CT. Methods: Retrospective study was made at Hospital of Leon (Spain), including 37 patients with locally advanced NSCLC treated with durvalumab after CRT treatment between March 2018 and october 2021 (40.5% patients were included in the durvalumab early access program). The neutrophil-to-lymphocyte ratio (NLR) could identified after CRT as a factor that may be benefit from durvalumab. Results: Median age was 67 years (range 46-82 years). 40.5% of patients were _70 years old. 78.4% were male and 51.4% smokers. 54% had non-squamous histology. PD-L1 expression was <1% in 5% and not available in 8% patients. 2.7% ROS1 rearrangements, 5.4% KRAS mutations and not available in 43.2% patients. Stage IIIA, IIIB, IIIC disease were 24.3%, 54.1% and 21.6%, respectively. Median time from end of CRT to onset durvalumab was 44 days (range 13-120 days). Overall median CT duration was 214.8 days (range 69-399 days) with a median of 14 infusions (range 6-27 infusions). With a median follow up of 19.7 months (range 1.4-34.9 months); 67.6% had stopped CT: 37.8% due to completing treatment, 16.2% disease progression, 10.8% adverse event and 2.7% due to COVID19 infection. Median real-world progressionfree survival (rwPFS) was 17 months (95% CI, 11-23). Median realworld overall survival (rwOS) was 29.9 months (95% CI, 23.3-36.6). % rwOS at 6, 18 and 24 months were 100%, 86.9% and 74.5%, respectively. For patients with post-CRT NLR not exceeding the cohort median value of 6, receipt of durvalumab was associated with an improvement in rwOS (median not reached vs 25.7 months; p¼0.025). 56.8% patients had any grade of radiation pneumonitis (median time from CRT start: 119 days [range 36-241 days]). Of these, 19% patients developed worsening of radiation pneumonitis with durvalumab. 54,1% developed immune-mediated toxicity, mostly G1-2 (85.1%). Conclusions: Our results demonstrate the effectiveness of durvalumab consolidation in this patients population in a real-life setting. We identified low NLR after CRT as a potentially predictive factor for the benefit of CT in locally advanced NSCLC.S

    La estructura sísmica de la corteza de la Zona de Ossa Morena y su interpretación geológica

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    El experimento de sísmica de reflexión profunda IBERSEIS ha proporcionado una imagen de la corteza del Orógeno Varisco en el sudoeste de Iberia. Este artículo se centra en la descripción de la corteza de la Zona de Ossa Morena (OMZ), que está claramente dividida en una corteza superior, con reflectividad de buzamiento al NE, y una corteza inferior de pobre reflectividad. Las estructuras geológicas cartografiadas en superficie se correlacionan bien con la reflectividad de la corteza superior, y en la imagen sísmica se ven enraizar en la corteza media. Ésta está constituida por un cuerpo muy reflectivo, interpretado como una gran intrusión de rocas básicas. La imagen de las suturas que limitan la OMZ muestra el carácter fuertemente transpresivo de la colisión orogénica varisca registrada en el sudoeste de Iberia. La Moho actual es plana y, en consecuencia, no se observa la raíz del orógeno

    Spatial distribution modelling reveals climatically suitable areas for bumblebees in undersampled parts of the Iberian Peninsula

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    The Iberian Peninsula supports a high diversity of bumblebees, with 38 species all of which are at or near the south-western edge of their range. We might expect them to be threatened by climate change, but their distributions within Iberia are poorly documented. In this study, we examine the climatic conditions that explain the distribution of Iberian bumblebees. Species distribution models (SDMs) were built using a presence-only technique (Maxent), incorporating presence data of Iberian bumblebees (initially 5795 records for 38 species) with seven climatic variables. We observed that: (i) mountain regions were highlighted as rich in species (bumblebee hot spots); (ii) rare species are climatic specialist species that mainly inhabit mountain regions; (iii) common species are more tolerant of a broader range of climates, notably of higher temperatures; (iv) some areas of Iberia are largely undersampled, including areas predicted to support high bumblebee diversity. We identify areas where targeted searches may reveal undiscovered populations of rare bumblebee species. Obtaining a good knowledge of the current distribution of species is a vital first step towards devising approaches for their conservation

    Transitions of cardio-metabolic risk factors in the Americas between 1980 and 2014

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    Describing the prevalence and trends of cardiometabolic risk factors that are associated with non-communicable diseases (NCDs) is crucial for monitoring progress, planning prevention, and providing evidence to support policy efforts. We aimed to analyse the transition in body-mass index (BMI), obesity, blood pressure, raised blood pressure, and diabetes in the Americas, between 1980 and 2014

    State of the climate in 2013

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    In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Niña or El Niño events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earths surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series. © 2014, American Meteorological Society. All rights reserved
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