Neste artigo, abordamos o desenvolvimento dos mapeamentos de galáxias e a sua importância para a astrofísica extragaláctica e para a cosmologia. Acompanhando a evolução dos telescópios, instrumentos e técnicas de observação astronômica desde o século XIX, discutimos como os avanços tecnológicos permitiram desvelar propriedades fundamentais do universo, tal como sua dinâmica, composição e sua estrutura em grande escala. Os mapeamentos de galáxias também revelaram a presença de matéria escura em diferentes escalas e seu impacto tanto na topologia da teia cósmica quanto nos processos de formação e evolução das galáxias. Observações das diferentes propriedades das galáxias individuais e suas correlações espaciais induzidas pelo ambiente local fornecem evidências para testar diferentes modelos físicos da interação gravitacional e seu impacto nos processos energéticos que contribuem para moldar os diferentes tipos de galáxias e suas características. Simulações de n-corpos possuem um papel crucial na reprodução da formação e evolução das estruturas cósmicas, permitindo contrastar as observações com universos simulados e testar teorias e hipóteses sobre a dinâmica do universo e a formação de galáxias. Em suma, a análise da estrutura em grande escala e dos efeitos ambientais na formação e evolução das galáxias ilustram a conexão complexa entre a cosmologia e a astrofísica modernas e ressalta a importância dos mapeamentos de galáxias para melhor entendê-las, apontando para o potencial de descobertas futuras à medida que as tecnologias e métodos observacionais continuem a evoluir.
Daily, moderate hypofractionation has become standard treatment for breast cancer following breast-conserving surgery, although substantial variation exists in its use. This paper describes the generation of consensus-based recommendations for the utilisation of this therapy at the healthcare system level and compares these to American Society for Radiation Oncology (ASTRO) guidelines. Consensus-based guidelines were developed in three steps, including a systematic literature review and involvement of radiation oncologists specialising in breast cancer in Catalonia: (a) creation of a working group and evidence review; (b) consideration of the levels of evidence and agreement on the formulation of survey questions; and (c) performance of survey and development of consensus-based recommendations. Results were compared to the ASTRO recommendations. Consensus was above 80% for 10 of the 14 survey items. Experts supported hypofractionated radiotherapy for all breast cancer patients aged 40 years or more; with invasive carcinoma and breast-conserving surgery; without radiation of lymph nodes; and regardless of the tumour size, histological grade, molecular subtype, breast size, laterality, other treatment characteristics, or need for a boost. Over half favoured its use in all situations, even where available scientific evidence is insufficient. The resulting recommendations and the quality of the evidence are comparable to those from ASTRO, despite some differences in the degree of consensus. Specialists agree that hypofractionation is the standard treatment for breast cancer following breast-conserving surgery, but some specific areas require a higher level of evidence before unequivocally extending indications.
The Galileo Project is the first systematic scientific research program in search for potential astro-archaeological artifacts or remnants of extraterrestrial technological civilizations (ETCs) or potentially active equipment near Earth. Taking a path not taken, it conceivably may pick some low-hanging fruit, and without asserting probabilities - make discoveries of ETC-related objects, which would have far-reaching implications for science and our worldview.
Purpose/Objective We present our single-institution experience in the management of invasive breast cancer with targeted intraoperative radiotherapy (TARGIT-IORT), focusing on patient suitability for IORT determined by the American Society for Radiation Oncology (ASTRO) Accelerated Partial Breast Irradiation (APBI) consensus guidelines. Materials/Methods We identified 237 patients treated for biopsy-proven early-stage invasive breast cancer using low energy x-ray TARGIT-IORT at the time of lumpectomy between September 2013 and April 2020 who were prospectively enrolled in an institutional review board (IRB) approved database. We retrospectively reviewed preoperative and postoperative clinicopathologic factors to determine each patient’s ASTRO APBI suitability (suitable, cautionary or unsuitable) according to the 2017 consensus guidelines (CG). Change in suitability group was determined based on final pathology. Kaplan-Meier methods were used to estimate the survival probability and recurrence probability across time. Results 237 patients were included in this analysis, based on preoperative clinicopathologic characteristics, 191 (80.6%) patients were suitable, 46 (19.4%) were cautionary and none were deemed unsuitable. Suitability classification changed in 95 (40%) patients based on final pathology from lumpectomy. Increasing preoperative lesion size or a body mass index (BMI) ≥ 30 kg/m2 were significant predictors for suitability group change. Forty-one (17.3%) patients received additional adjuvant whole breast radiotherapy after TARGIT-IORT. At a median follow up of 38.2 months (range 0.4 – 74.5), five (2.1%) patients had ipsilateral breast tumor recurrences (IBTR), including two (0.8%) true local recurrences defined as a recurrence in the same quadrant as the initial lumpectomy bed with the same histology as the initial tumor. IBTR occurred in 1/103 (0.09%) patient in the post-op suitable group, 4/98 (4.08%) patients in the post-op cautionary group, and no patients in the post-op unsuitable group. At 3-years, the overall survival rate was 98.4% and the local recurrence free survival rate was 97.1%. Conclusion There is a low rate of IBTR after TARGIT-IORT when used in appropriately selected patients. Change in suitability classification pre to postoperatively is common, highlighting a need for further investigation to optimize preoperative patient risk stratification in this setting. Patients who become cautionary or unsuitable based on final pathology should be considered for additional adjuvant therapy.
Background: Although chest radiographs have not been utilised well for classifying stroke subtypes, they could provide a plethora of information on cardioembolic stroke. This study aimed to develop a deep convolutional neural network that could diagnose cardioembolic stroke based on chest radiographs. Methods: Overall, 4,064 chest radiographs of consecutive patients with acute ischaemic stroke were collected from a prospectively maintained stroke registry. Chest radiographs were randomly partitioned into training/validation (n = 3,255) and internal test (n = 809) datasets in an 8:2 ratio. A densely connected convolutional network (ASTRO-X) was trained to diagnose cardioembolic stroke based on chest radiographs. The performance of ASTRO-X was evaluated using the area under the receiver operating characteristic curve. Gradient-weighted class activation mapping was used to evaluate the region of focus of ASTRO-X. External testing was performed with 750 chest radiographs of patients with acute ischaemic stroke from 7 hospitals. Findings: The areas under the receiver operating characteristic curve of ASTRO-X were 0.86 (95% confidence interval [CI], 0.83–0.89) and 0.82 (95% CI, 0.79–0.85) during the internal and multicentre external testing, respectively. The gradient-weighted class activation map demonstrated that ASTRO-X was focused on the area where the left atrium was located. Compared with cases predicted as non-cardioembolism by ASTRO-X, cases predicted as cardioembolism by ASTRO-X had higher left atrial volume index and lower left ventricular ejection fraction in echocardiography. Interpretation: ASTRO-X, a deep neural network developed to diagnose cardioembolic stroke based on chest radiographs, demonstrated good classification performance and biological plausibility.
Alessandra Sorrentino, G. Mancioppi, Luigi Coviello
et al.
This study aims to investigate the role of several aspects that may influence human–robot interaction in assistive scenarios. Among all, we focused on semi-permanent qualities (i.e., personality and cognitive state) and temporal traits (i.e., emotion and engagement) of the user profile. To this end, we organized an experimental session with 11 elderly users who performed a cognitive assessment with the non-humanoid ASTRO robot. ASTRO robot administered the Mini Mental State Examination test in Wizard of Oz setup. Temporal and long-term qualities of each user profile were assessed by self-report questionnaires and by behavioral features extrapolated by the recorded videos. Results highlighted that the quality of the interaction did not depend on the cognitive state of the participants. On the contrary, the cognitive assessment with the robot significantly reduced the anxiety of the users, by enhancing the trust in the robotic entity. It suggests that the personality and the affect traits of the interacting user have a fundamental influence on the quality of the interaction, also in the socially assistive context.
We perform a statistical inference of the astrophysical population of binary black hole (BBH) mergers observed during the first two observing runs of Advanced LIGO and Advanced Virgo, including events reported in the GWTC-1 and IAS catalogs. We derive a novel formalism to fully and consistently account for events of arbitrary significance. We carry out a software injection campaign to obtain a set of mock astrophysical events subject to our selection effects, and use the search background to compute the astrophysical probabilities $p_{\rm astro}$ of candidate events for several phenomenological models of the BBH population. Finally, we combine the information from individual events to infer the rate, spin, mass, mass-ratio and redshift distributions of the mergers. The existing population does not discriminate between random spins with a spread in the effective spin parameter, and a small but nonzero fraction of events from tidally-torqued stellar progenitors. The mass distribution is consistent with one having a cutoff at $m_{\rm max} = 41^{+10}_{-5}\,\rm M_\odot$, while the mass ratio favors equal masses; the mean mass ratio $\bar q> 0.67$. The rate shows no significant evolution with redshift. We show that the merger rate restricted to BBHs with a primary mass between 20 and $30\, \rm M_\odot$, and a mass ratio $q > 0.5$, and at $z \sim 0.2$, is 1.5 to $5.3\,{\rm Gpc^{-3} yr^{-1}}$ (90\% c.l.); these bounds are model independent and a factor of $\sim 3$ tighter than that on the local rate of all BBH mergers, and hence are a robust constraint on all progenitor models. Including the events in our catalog increases the Fisher information about the BBH population by $\sim 47\%$, and tightens the constraints on population parameters.
Considere ao pé-da-letra a expressão "imagem de um buraco negro", atribuindo a cada palavra o significado usual. Verá que ela não faz muito sentido e, se faz, soa estranha. É que a expressão é científica. Cada palavra adquiriu significado num vasto contexto de conceitos articulados numa teoria; esses conceitos, por sua vez, muitas vezes têm referências empíricas laboratoriais ou observacionais (astronômicas); o desenrolar histórico, normalmente imprevisível de descobertas observacionais ou de criações intelectuais, também adiciona às palavras, não explicações causais, mas meras referências casuais. Considerando a importância da popularização da ciência, como meio de promover a necessária alfabetização e letramento científico do público em geral, resolvi tirar vantagem da empolgação científica já suscitada pela grande mídia, quando anunciou a primeira imagem de um buraco negro. Não era mais preciso interessar as pessoas, pois elas já estavam interessadas no tema. Porém, notas quase telegráficas de jornais e noticiários atingem apenas superficialmente o público. Como teste de uma estratégia de divulgação científica e, também, como experimento de comunicação científica, decidi preparar e oferecer ao público um texto, antes de tudo elucidador do conteúdo científico e da complexa técnica de obtenção da imagem, mas também crítico do modo científico de investigar a natureza e incitador da aplicação da ciência, na medida em que ela possa tornar o mundo melhor e mais humano.
After a decade of design and construction, South Africa's SKA-MID precursor MeerKAT has begun its science operations. To make full use of the widefield capability of the array, it is imperative that we have an accurate model of the primary beam of its antennas. We have used an available L-band full-polarization astro-holographic observation and electromagnetic simulation to create sparse representations of the beam using principal components and Zernike polynomials. The spectral behaviour of the spatial coefficients has been modelled using discrete cosine transform. We have provided the Zernike-based model over a diameter of 10 degrees in an associated software tool that can be useful for direction dependent calibration and imaging. The model is more accurate for the diagonal elements of the beam Jones matrix and at lower frequencies. As we get more accurate beam measurements and simulations in the future, especially for the cross-polarization patterns, our pipeline can be used to create more accurate sparse representations of MeerKAT beam.
Dark sectors, consisting of new, light, weakly-coupled particles that do not interact with the known strong, weak, or electromagnetic forces, are a particularly compelling possibility for new physics. Nature may contain numerous dark sectors, each with their own beautiful structure, distinct particles, and forces. This review summarizes the physics motivation for dark sectors and the exciting opportunities for experimental exploration. It is the summary of the Intensity Frontier subgroup "New, Light, Weakly-coupled Particles" of the Community Summer Study 2013 (Snowmass). We discuss axions, which solve the strong CP problem and are an excellent dark matter candidate, and their generalization to axion-like particles. We also review dark photons and other dark-sector particles, including sub-GeV dark matter, which are theoretically natural, provide for dark matter candidates or new dark matter interactions, and could resolve outstanding puzzles in particle and astro-particle physics. In many cases, the exploration of dark sectors can proceed with existing facilities and comparatively modest experiments. A rich, diverse, and low-cost experimental program has been identified that has the potential for one or more game-changing discoveries. These physics opportunities should be vigorously pursued in the US and elsewhere.
Radiotherapy is a fundamental component of treatment for the majority of patients with cancer. In recent decades, technological advances have enabled patients to receive more targeted doses of radiation to the tumor, with sparing of adjacent normal tissues. There had been hope that the era of precision medicine would enhance the combination of radiotherapy with targeted anticancer drugs; however, this ambition remains to be realized. In view of this lack of progress, the FDA–AACR–ASTRO Clinical Development of Drug–Radiotherapy Combinations Workshop was held in February 2018 to bring together stakeholders and opinion leaders from academia, clinical radiation oncology, industry, patient advocacy groups, and the FDA to discuss challenges to introducing new drug–radiotherapy combinations to the clinic. This Perspectives in Regulatory Science and Policy article summarizes the themes and action points that were discussed. Intelligent trial design is required to increase the number of studies that efficiently meet their primary outcomes; endpoints to be considered include local control, organ preservation, and patient-reported outcomes. Novel approaches including immune-oncology or DNA-repair inhibitor agents combined with radiotherapy should be prioritized. In this article, we focus on how the regulatory challenges associated with defining a new drug–radiotherapy combination can be overcome to improve clinical outcomes for patients with cancer.
A bstractWe propose a simplified model of dark matter with a scalar mediator to accommodate the di-photon excess recently observed by the ATLAS and CMS collaborations. Decays of the resonance into dark matter can easily account for a relatively large width of the scalar resonance, while the magnitude of the total width combined with the constraint on dark matter relic density leads to sharp predictions on the parameters of the Dark Sector. Under the assumption of a rather large width, the model predicts a signal consistent with ∼ 300 GeV dark matter particle and ∼ 750 GeV scalar mediator in channels with large missing energy. This prediction is not yet severely bounded by LHC Run I searches and will be accessible at the LHC Run II in the jet plus missing energy channel with more luminosity. Our analysis also considers astro-physical constraints, pointing out that future direct detection experiments will be sensitive to this scenario.
One of the main goals of the feasibility study MOSE (MOdellig ESO Sites) is to evaluate the performances of a method conceived to forecast the optical turbulence above the ESO sites of the Very Large Telescope and the European-Extremely Large Telescope in Chile. The method implied the use of a dedicated code conceived for the optical turbulence (OT) called Astro-Meso-Nh. In this paper we present results we obtained at conclusion of this project concerning the performances of this method in forecasting the most relevant parameters related to the optical turbulence (CN2, seeing , isoplanatic angle theta_0 and wavefront coherence time tau_0). Numerical predictions related to a very rich statistical sample of nights uniformly distributed along a solar year and belonging to different years have been compared to observations and different statistical operators have been analyzed such as classical bias, RMSE and and more sophisticated statistical operators derived by the contingency tables that are able to quantify the score of success of a predictive method such as the percentage of correct detection (PC) and the probability to detect a parameter within a specific range of values (POD). The main conclusions of the study tell us that the Astro-Meso-Nh model provides performances that are already very good to definitely guarantee a not negligible positive impact on the Service Mode of top-class telescopes and ELTs. A demonstrator for an automatic and operational version of the Astro-Meso-Nh model will be soon implemented on the sites of VLT and E-ELT.
We deployed two wavelength calibrators based on laser frequency combs ("astro-combs") at an astronomical telescope. One astro-comb operated over a 100 nm band in the deep red (∼ 800 nm) and a second operated over a 20 nm band in the blue (∼ 400 nm). We used these red and blue astro-combs to calibrate a high-resolution astrophysical spectrograph integrated with a 1.5 m telescope, and demonstrated calibration precision and stability sufficient to enable detection of changes in stellar radial velocity < 1 m/s.