The Massive Star Content of NGC 3603

We investigate the massive star content of NGC 3603, the closest known giant H II region. We have obtained spectra of 26 stars in the central cluster using the Baade 6.5-m telescope (Magellan I). Of these 26 stars, 16 had no previous spectroscopy. We also obtained photometry of all of the stars with previous or new spectroscopy, primarily using archival HST ACS/HRC images. We use these data to derive an improved distance to the cluster, and to construct an H-R diagram for discussing the masses and ages of the massive star content of this cluster.Comment: Accepted by the Astronomical Journal. This revision updates the coordinates in Table 1 by (-0.18sec, +0.2") to place them on the UCAC2 syste

The Environments of High-Redshift Quasi-Stellar Objects

We present a sample of i_(775)-dropout candidates identified in five Hubble Advanced Camera for Surveys (ACS) fields centered on Sloan Digital Sky Survey quasi-stellar objects (QSOs) at redshift z ~ 6. Our fields are as deep as the GOODS ACS images, which are used as a reference field sample. We find them to be overdense in two fields, underdense in two fields, and as dense as the average density of GOODS in one field. The two excess fields show significantly different color distributions from that of GOODS at the 99% confidence level, strengthening the idea that the excess objects are indeed associated with the QSO. The distribution of i_(775)-dropout counts in the five fields is broader than that derived from GOODS at the 80%-96% confidence level, depending on which selection criteria were adopted to identify i_(775)-dropouts; its width cannot be explained by cosmic variance alone. Thus, QSOs seem to affect their environments in complex ways. We suggest the picture where the highest redshift QSOs are located in very massive overdensities and are therefore surrounded by an overdensity of lower mass halos. Radiative feedback by the QSO can in some cases prevent halos from becoming galaxies, thereby generating in extreme cases an underdensity of galaxies. The presence of both enhancement and suppression is compatible with the expected differences between lines of sight at the end of reionization as the presence of residual diffuse neutral hydrogen would provide young galaxies with shielding from the radiative effects of the QSO

Star-formation in the HI bridge between M81 and M82

We present multi-wavelength observations of stellar features in the HI tidal bridge connecting M81 and M82 in the region called Arp's Loop. We identify eight young star-forming regions from Galaxy Evolution Explorer ultraviolet observations. Four of these objects are also detected at H\alpha. We determine the basic star formation history of Arp's Loop using F475W and F814W images obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope. We find both a young (1 Gyr) stellar population with a similar spatial distribution and a metallicity Z~0.004. We suggest that the old stellar population was formed in the stellar disk of M82 and/or M81 and ejected into the intergalactic medium during a tidal passage (~ 200-300 Myr ago), whereas the young UV-bright stars have formed in the tidal debris. The UV luminosities of the eight objects are modest and typical of small clusters or OB associations. The tidal bridge between M81-M82 therefore appears to be intermediate between the very low levels of star formation seen in the Magellanic bridge and actively star-forming tidal tails associated with major galaxy mergers.Comment: Astronomical Journal accepte

The Environments of High Redshift QSOs

We present a sample of $i_{775}$-dropout candidates identified in five Hubble Advanced Camera for Surveys fields centered on Sloan Digital Sky Survey QSOs at redshift $z\sim 6$. Our fields are as deep as the Great Observatory Origins Deep Survey (GOODS) ACS images which are used as a reference field sample. We find them to be overdense in two fields, underdense in two fields, and as dense as the average density of GOODS in one field. The two excess fields show significantly different color distributions from that of GOODS at the 99% confidence level, strengthening the idea that the excess objects are indeed associated with the QSO. The distribution of $i_{775}$-dropout counts in the five fields is broader than that derived from GOODS at the 80% to 96% confidence level, depending on which selection criteria were adopted to identify $i_{775}$-dropouts; its width cannot be explained by cosmic variance alone. Thus, QSOs seem to affect their environments in complex ways. We suggest the picture where the highest redshift QSOs are located in very massive overdensities and are therefore surrounded by an overdensity of lower mass halos. Radiative feedback by the QSO can in some cases prevent halos from becoming galaxies, thereby generating in extreme cases an underdensity of galaxies. The presence of both enhancement and suppression is compatible with the expected differences between lines of sight at the end of reionization as the presence of residual diffuse neutral hydrogen would provide young galaxies with shielding from the radiative effects of the QSO.Comment: 27 pages, 10 figures, submitted to Ap

Анализ клинических характеристик пациентов со злокачественными новообразованиями поджелудочной железы, получивших медицинскую помощь в стационарах Санкт-Петербурга в период с 2015 по 2020 год

The objective of the study was the analysis of the main clinical characteristics identified in patients with malignant neoplasms of the pancreas, who received medical care in healthcare institutions of St. Petersburg in the period from 2015 to 2020.Methods and materials. A continuous study of clinical and statistical data of patients with pancreatic cancer receiving medical care in healthcare institutions of St. Petersburg (of federal and city subordination) for the period from 01.2015 to 02.2020 was carried out. In total, the study included depersonalized medical cards of 2141 patients diagnosed with pancreatic cancer.Results. During the studied period, more than half of the patients diagnosed with cancer of the pancreas received medical care in specialized oncological institutions of city subordination, a third – in federal institutions, 11.3 % – in multidisciplinary city hospitals. The maximum number of cases was in patients of older age groups: 41.7 % – 70 years and over, including 15.4 % – 80 years and over. The majority (39.7 %) of new patients with pancreatic cancer hospitalized in medical institutions of St. Petersburg were diagnosed with stage IV of the disease. The disease, according to examinations, was represented by stage III in 29.7 % of patients at the time of initial hospitalization. The pancreatic cancer was presented with stage III in 20 % of the patients. The disease was registered in 4.4 % of patients at stage I. Stage 0 or carcinoma in situ was diagnosed at initial presentation in 4.7 % of patients. The stage of the disease was not determined in 1.4 % of patients. The tumor was located in the head of the pancreas in 64.4 % of patients. The most common histological type of pancreatic cancer is ductal adenocarcinoma, which was verified in 72.0 % of patients. Type 2 diabetes mellitus was registered in 37 % of patients as concomitant disease.Conclusion. The results of the analysis of clinical and statistical data of patients with pancreatic cancer may become a background for conducting research on the early detection of this neoplasm.Цель – проанализировать основные клинические характеристики, выявленные у пациентов, страдающих злокачественными новообразованиями поджелудочной железы (ЗНО ПЖ), получивших медицинскую помощь в учреждениях здравоохранения Санкт-Петербурга в период с 2015 по 2020 г.Методы и материалы. Проведено сплошное исследование клинических и статистических данных пациентов, страдающих ЗНО ПЖ, получивших медицинскую помощь в учреждениях здравоохранения СПб. (федерального и городского подчинения) за период с января 2015 г. по февраль 2020 г. Всего в исследование включены обезличенные карты 2141 больного с диагнозом «ЗНО ПЖ».Результаты. За изученный период времени более половины пациентов с установленным диагнозом «ЗНО ПЖ» получили медицинскую помощь в специализированных онкологических учреждениях городского подчинения, треть – в федеральных учреждениях, 11,3 % – в многопрофильных городских стационарах. Максимальный удельный вес приходился на пациентов старших возрастных групп. Лица в возрасте 70 лет и старше составили 41,7 %, в том числе 15,4 % – 80 лет и старше. У бóльшей части (39,7 %) первичных пациентов с ЗНО ПЖ, госпитализированных в медицинские учреждения Санкт-Петербурга, была диагностирована IV стадия заболевания. У 29,7 % больных на момент первичной госпитализации заболевание, по данным обследований, было представлено III стадией. У 20 % пациентов ЗНО ПЖ было представлено II стадией. Заболевание на I стадии было зарегистрировано у 4,4 % больных. Стадия 0, или карцинома in situ, была установлена при первичном обращении у 4,7 % пациентов. У 1,4 % пациентов стадия заболевания не была определена.У 64,4 % пациентов опухоль располагалась в головке поджелудочной железы. Наиболее распространенным гистологическим типом ЗНО ПЖ была протоковая аденокарцинома, которая была верифицирована у 72,0 % больных. У 37 % пациентов в анамнезе сопутствующей патологии зарегистрирован сахарный диабет II типа.Заключение. Результаты проведенного анализа клинических и статистических данных пациентов с ЗНО ПЖ могут стать предпосылкой для проведения исследований по раннему выявлению данной неоплазии

A Golden Standard Type Ia Supernova SN 2005cf: Observations from the Ultraviolet to the Near-Infrared Wavebands

We present extensive photometry at ultraviolet (UV), optical, and near-infrared (NIR) wavelengths, as well as dense sampling of optical spectra, for the normal type Ia supernova (SN Ia) 2005cf. From the well-sampled light curves, we find that SN 2005cf reached a B-band maximum at 13.63+/-0.02 mag, with an observed luminosity decline rate dm_15(B) = 1.05+/-0.03 mag. The correlations between the decline rate and various color indexes, recalibrated on the basis of an expanded SN Ia sample, yielded E(B-V)_host=0.09+/-0.03 mag for SN2005cf. The UV photometry was obtained with the HST and the Swift Ultraviolet/Optical Telescope, and the results match each other to within 0.1-0.2 mag. The UV light curves show similar evolution to the broadband U, with an exception in the 2000-2500 Angstrom spectral range (corresponding to the F220W/uvm2 filters), where the light curve appears broader and much fainter than that on either side (likely owing to the intrinsic spectral evolution). Combining the UV data with the ground-based optical and NIR data, we establish the generic UV-optical-NIR bolometric light curve for SN 2005cf and derive the bolometric corrections in the absence of UV and/or NIR data. The overall spectral evolution of SN 2005cf is similar to that of a normal SN Ia, but with variety in the strength and profile of the main feature lines. The spectra at early times displayed strong, detached high-velocity (HV) features in the Ca II H&K doublet and NIR triplet. Similar HV features may exist in the SiII 6355 absorption line which evolved rapidly from a flat-bottomed feature in the earliest phase to a triangular shape one week before maximum, and may be common in other normal SNe Ia. The possible origin of the HV absorption features is briefly discussed (abridged).Comment: 31 pages, 24 figures, 13 tables, emulateapj; submitted to Ap

Анализ видов медицинских вмешательств пациентам с аденокарциномой поджелудочной железы в условиях стационаров Санкт-Петербурга за период с 2014 г. по 2020 г.

Introduction. In view of the course of the disease, patients suffering from pancreatic adenocarcinoma go through all stages of medical care in St. Petersburg. To date, in the available literature, there are no works devoted to the analysis of the types, volumes and outcomes of medical interventions performed in this category of patients. The data obtained from such an analysis can become the basis for the development of algorithms and programs for optimizing the provision of care for patients suffering from this pathology. The objective of the study was to analyze the types of medical interventions for patients suffering from pancreatic cancer in hospitals in St. Petersburg for the period from 2014 to 2020. Methods and materials. The study group consisted of a continuous sampling of data from 2414 cards of patients diagnosed with pancreatic adenocarcinoma who applied to medical organizations in St. Petersburg in the period from 2014 to 2020. The provided medical interventions were divided into the following types: radical, symptomatic and palliative treatment. Results. In 69.4 % of patients in the study sample during the initial visit, stage III and IV of the disease were diagnosed. The volumes and methods of treatment differed for different localizations of the tumor node. In patients with a tumor lesion of the head of the pancreas, «symptomatic treatment» was most often used, in patients with localization of the neoplastic process in the body of the pancreas, «diagnostic surgery» was most often performed, in the case of damage to the tail of the pancreas, the main method of treatment was «radical surgery». In federal medical organizations, «symptomatic treatment» was most often performed. In specialized oncological medical organizations of the city, «radical», «symptomatic» and «diagnostic» interventions were performed in the same way. In city multidisciplinary hospitals, «symptomatic treatment» was most often performed. Conclusion. The data obtained should be taken into account when improving and developing new programs for the detection of pancreatic adenocarcinoma at early stages. Further monitoring of medical interventions in this category of patients is required.Введение. Ввиду течения заболевания пациенты, страдающие аденокарциномой поджелудочной железы, проходят через все этапы оказания медицинской помощи в Санкт-Петербурге. На сегодняшний день в доступной литературе отсутствуют работы, посвященные анализу видов, объемов и исходов медицинских вмешательств, проводимых у этой категории пациентов. Полученные данные такого анализа могут стать основой для разработки алгоритмов и программ оптимизации оказания помощи пациентам, страдающим этой патологией. Цель – проанализировать виды медицинских вмешательств пациентам, страдающим злокачественными новообразованиями поджелудочной железы, в стационарах Санкт-Петербурга в период с 2014 г. по 2020 г. Методы и материалы. Исследуемую группу составила сплошная выборка данных 2414 карт пациентов с диагнозом «аденокарцинома поджелудочной железы», обратившихся в медицинские организации Санкт-Петербурга в период с 2014 по 2020 г. Оказанные медицинские вмешательства разделены на следующие виды: радикальное, симптоматическое и паллиативное лечение. Результаты. У 69,4 % пациентов исследуемой выборки при первичном обращении были диагностированы III и IV стадии заболевания. Объемы и методы лечения отличались при разных локализациях опухолевого узла. У больных с опухолевым поражением головки поджелудочной железы наиболее часто применяли симптоматическое лечение, у пациентов с локализацией неопластического процесса в теле железы чаще всего выполняли диагностическое операции, в случае поражения хвоста железы основным методом лечения была радикальная операция. В федеральных медицинских организациях наиболее часто проводили симптоматическое лечение. В специализированных онкологических медицинских организациях города радикальные, симптоматические и диагностические вмешательства выполнены в одинаковом отношении. В городских многопрофильных стационарах наиболее часто выполняли симптоматическое лечение. Заключение. Полученные данные необходимо учитывать при совершенствовании и разработке новых программ выявления аденокарциномы поджелудочной железы на ранних стадиях. Требуется дальнейшее проведение мониторинга медицинских вмешательств данной категории пациентов.