Room temperature coexistence of large electric polarization and magnetic order in BiFeO3 single crystals

From an experimental point of view, room temperature ferroelectricity in BiFeO3 is raising many questions. Electric measurements made a long time ago on solid-solutions of BiFeO3 with Pb(Ti,Zr)O3 indicate that a spontaneous electric polarization exists in BiFeO3 below the Curie temperature TC=1143K. Yet in most reported works, the synthesised samples are too conductive at room temperature to get a clear polarization loop in the bulk without any effects of extrinsic physical or chemical parameters. Surprisingly, up to now there has been no report of a P(E) (polarization versus electric field) loop at room temperature on single crystals of BiFeO3. We describe here our procedure to synthesize ceramics and to grow good quality sizeable single crystals by a flux method. We demonstrate that BiFeO3 is indeed ferroelectric at room-temperature through evidence by Piezoresponse Force Microscopy and P(E) loops. The polarization is found to be large, around 60 microC/cm2, a value that has only been reached in thin films. Magnetic measurements using a SQUID magnetometer and Mossbauer spectroscopy are also presented. The latter confirms the results of NMR measurements concerning the anisotropy of the hyperfine field attributed to the magnetic cycloidal structure.Comment: 27 pages, 12 figure

Математико-статистическая оценка персистирующих возбудителей как факторов риска внебольничной пневмонии и острого бронхита у детей

The aim of this study was to determine the relationship between infection with “persistent” agents of children and the possibility of the development of inflammatory diseases of the respiratory tract such as community-acquired pneumonia and acute bronchitis on the basis of risk management concepts.Materials and methods. 701 children in age from 15 days to 16 years were examined in Nizhny Novgorod and the Nizhny Novgorod region with clinically and radiologically confirmed diagnosis: community-acquired pneumonia, acute bronchitis. This study was performed in the period from 2005 to 2014. The control group consisted of 127 healthy children of different ages. The detection of M. pneumoniae, Сytomegalovirus, Herpes simplex I/II C. pneumoniae was performed by PCR. The concept of risk determination was based on the determination of the absolute risk in the exposed and the no exposed groups, attributable risk, relative risk, the population attributable risk, as well as determining the standard errors for each type of risk and confidence interval.Results. Attributable risk, relative risk, population-attributable risk are statistically significant figures. Attributable risk of development of community-acquired pneumonia was 29,26%; 27,37%; 25,70%; 20,21% for the M. pneumoniae, C. pneumoniae, CMV, HSV I / II respectively. The relative risk was 1,43 for the M. pneumoniae; 1,38 – for C. pneumoniae and CMV; 1,28- for HSV I / II. The presence of persistent pathogens is resulting in increased incidence of communityacquired pneumonia throughout the population (population attributable risk): 4,75% for M. pneumoniae, 0,23% for C. pneumoniae, 5,59% for the CMV and 1,08% for the HSV I/II. Similar calculations were performed for patients with acute bronchitis. The statistical analysis allowed to exclude C. pneumoniae and HSV I / II of the risk factors for communityacquired pneumonia and acute bronchitis.Conclusion. The findings suggest the influence of M. pneumoniae and CMV in the development of communityacquired pneumonia and acute bronchitis in children. C. pneumoniae, and HSV I / II do not play a statistically significant role in the overall landscape of etiologic agents of community-acquired pneumonia and acute bronchitis.Целью данного исследования явилось определение связи между инфицированностью «персистирующими» возбудителями детей и возможностью развития воспалительных заболеваний респираторного тракта, таких как внебольничная пневмония и острый бронхит на основании концепции факторов рисков.Материалы и методы. В период с 2005 по 2014 г. обследован 701 ребенок из г. Нижнего Новгорода и Нижегородской области в возрасте от 15 дней до 16 лет с рентгенологически и клинически подтвержденными диагнозами: внебольничная пневмония, острый бронхит. Контрольную группу составили 127 практически здоровых детей разных возрастов. Детекцию M. pneumoniae, Сytomegalovirus, Herpes simplex I/II C. pneumoniae осуществляли методом ПЦР. Концепция определения рисков строилась на определении абсолютного риска в экспонируемой и не экспонируемой группах, атрибутивного риска, относительного риска, популяционного атрибутивного риска, а также на определении стандартных ошибок для каждого вида риска и доверительного интервала.Результаты. Статистически значимыми показателями являются атрибутивный риск, относительный риск, популяционный атрибутивный риск. Атрибутивный риск развития внебольничной пневмонии составил 29,26%; 27,37%; 25,70%; 20,21% для M. pneumoniae, С. pneumoniae, CMV, HSV I/II соот- ветственно. Относительный риск составил 1,43 для M. pneumoniae; 1,38 – для С. pneumoniae и для CMV; 1,28 – для HSV I/II. Наличие персистирующих возбудителей приводит к увеличению заболеваемости внебольничной пневмонией по всей популяции (популяционный атрибутивный риск): на 4,75% для M. pneumoniae, 0,23% для С. pneumoniae, 5,59% для CMV и 1,08% для HSV I/II. Аналогичные расчеты были проведены для пациентов с острым бронхитом. Проведенный статистический анализ позволил исключить С. pneumoniae и HSV I/II из факторов риска развития внебольничной пневмонии и острого бронхита.Заключение. Полученные данные позволяют говорить о влиянии M. pneumoniae и CMV на развитие внебольничной пневмонии и острого бронхита у детей. С. pneumoniae и HSV I/II не играют статистически важной роли в общем пейзаже этиологических агентов внебольничной пневмонии и острого бронхита

Northern Eurasia Future Initiative (NEFI): facing the challenges and pathways of global change in the 21st century

During the past several decades, the Earth system has changed significantly, especially across Northern Eurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted in a variety of regional environmental changes that can have global consequences. The Northern Eurasia Future Initiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth Science Partnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoing environmental change, to inform societies and, thus, to better prepare societies for future developments. A key principle of NEFI is that these developments must now be secured through science-based strategies co-designed with regional decision makers to lead their societies to prosperity in the face of environmental and institutional challenges. NEESPI scientific research, data, and models have created a solid knowledge base to support the NEFI program. This paper presents the NEFI research vision consensus based on that knowledge. It provides the reader with samples of recent accomplishments in regional studies and formulates new NEFI science questions. To address these questions, nine research foci are identified and their selections are briefly justified. These foci include: warming of the Arctic; changing frequency, pattern, and intensity of extreme and inclement environmental conditions; retreat of the cryosphere; changes in terrestrial water cycles; changes in the biosphere; pressures on land-use; changes in infrastructure; societal actions in response to environmental change; and quantification of Northern Eurasia's role in the global Earth system. Powerful feedbacks between the Earth and human systems in Northern Eurasia (e.g., mega-fires, droughts, depletion of the cryosphere essential for water supply, retreat of sea ice) result from past and current human activities (e.g., large scale water withdrawals, land use and governance change) and potentially restrict or provide new opportunities for future human activities. Therefore, we propose that Integrated Assessment Models are needed as the final stage of global change assessment. The overarching goal of this NEFI modeling effort will enable evaluation of economic decisions in response to changing environmental conditions and justification of mitigation and adaptation efforts

Persistent pathogens as risk factors of community-acquired pneumonia and acute bronchitis in children

The aim of this study was to determine the relationship between infection with “persistent” agents of children and the possibility of the development of inflammatory diseases of the respiratory tract such as community-acquired pneumonia and acute bronchitis on the basis of risk management concepts.Materials and methods. 701 children in age from 15 days to 16 years were examined in Nizhny Novgorod and the Nizhny Novgorod region with clinically and radiologically confirmed diagnosis: community-acquired pneumonia, acute bronchitis. This study was performed in the period from 2005 to 2014. The control group consisted of 127 healthy children of different ages. The detection of M. pneumoniae, Сytomegalovirus, Herpes simplex I/II C. pneumoniae was performed by PCR. The concept of risk determination was based on the determination of the absolute risk in the exposed and the no exposed groups, attributable risk, relative risk, the population attributable risk, as well as determining the standard errors for each type of risk and confidence interval.Results. Attributable risk, relative risk, population-attributable risk are statistically significant figures. Attributable risk of development of community-acquired pneumonia was 29,26%; 27,37%; 25,70%; 20,21% for the M. pneumoniae, C. pneumoniae, CMV, HSV I / II respectively. The relative risk was 1,43 for the M. pneumoniae; 1,38 – for C. pneumoniae and CMV; 1,28- for HSV I / II. The presence of persistent pathogens is resulting in increased incidence of communityacquired pneumonia throughout the population (population attributable risk): 4,75% for M. pneumoniae, 0,23% for C. pneumoniae, 5,59% for the CMV and 1,08% for the HSV I/II. Similar calculations were performed for patients with acute bronchitis. The statistical analysis allowed to exclude C. pneumoniae and HSV I / II of the risk factors for communityacquired pneumonia and acute bronchitis.Conclusion. The findings suggest the influence of M. pneumoniae and CMV in the development of communityacquired pneumonia and acute bronchitis in children. C. pneumoniae, and HSV I / II do not play a statistically significant role in the overall landscape of etiologic agents of community-acquired pneumonia and acute bronchitis