485 research outputs found
Neural correlates of ‘pessimistic' attitude in depression
Background Preparing for potentially threatening events in the future is essential for survival. Anticipating the future to be unpleasant is also a cognitive key feature of depression. We hypothesized that ‘pessimism'-related emotion processing would characterize brain activity in major depression. Method During functional magnetic resonance imaging, depressed patients and a healthy control group were cued to expect and then perceive pictures of known emotional valences - pleasant, unpleasant and neutral - and stimuli of unknown valence that could have been either pleasant or unpleasant. Brain activation associated with the ‘unknown' expectation was compared with the ‘known' expectation conditions. Results While anticipating pictures of unknown valence, activation patterns in depressed patients within the medial and dorsolateral prefrontal areas, inferior frontal gyrus, insula and medial thalamus were similar to activations associated with expecting unpleasant pictures, but not with expecting positive pictures. The activity within a majority of these areas correlated with the depression scores. Differences between healthy and depressed persons were found particularly for medial and dorsolateral prefrontal and insular activations. Conclusions Brain activation in depression during expecting events of unknown emotional valence was comparable with activation while expecting certainly negative, but not positive events. This neurobiological finding is consistent with cognitive models supposing that depressed patients develop a ‘pessimistic' attitude towards events with an unknown emotional meaning. Thereby, particularly the role of brain areas associated with the processing of cognitive and executive control and of the internal state is emphasized in contributing to major depressio
Decoherence in a Talbot Lau interferometer: the influence of molecular scattering
We study the interference of C70 fullerenes in a Talbot-Lau interferometer
with a large separation between the diffraction gratings. This permits the
observation of recurrences of the interference contrast both as a function of
the de Broglie wavelength and in dependence of the interaction with background
gases. We observe an exponential decrease of the fringe visibility with
increasing background pressure and find good quantitative agreement with the
predictions of decoherence theory. From this we extrapolate the limits of
matter wave interferometry and conclude that the influence of collisional
decoherence may be well under control in future experiments with proteins and
even larger objects.Comment: 8 pages, 5 figure
Co-occurrence of intimate partner violence against mothers and maltreatment of their children with behavioral problems in Eastern Europe
This study investigates the co-occurrence of intimate partner violence (IPV) against mothers and their risk of perpetrating child maltreatment (CM) in North Macedonia, the Republic of Moldova, and Romania. Risk factors for IPV, CM, and their co-occurrence were identified. Two samples (N1 = 112, N2 = 701) of mothers with children with behavioral problems were assessed. IPV was reported by 64% of mothers, CM by 96%, and their co-occurrence by 63%. Mothers exposed to emotional IPV reported more physical and emotional CM. Mothers exposed to physical IPV reported more physical CM. Motheŕs own history of CM and offspring's behavior problems were associated with IPV and CM co-occurrence
Linear sampling method for identifying cavities in a heat conductor
We consider an inverse problem of identifying the unknown cavities in a heat
conductor. Using the Neumann-to-Dirichlet map as an input data, we develop a
linear sampling type method for the heat equation. A new feature is that there
is a freedom to choose the time variable, which suggests that we have more data
than the linear sampling methods for the inverse boundary value problem
associated with EIT and inverse scattering problem with near field data
Concept of an ionizing time-domain matter-wave interferometer
We discuss the concept of an all-optical and ionizing matter-wave
interferometer in the time domain. The proposed setup aims at testing the wave
nature of highly massive clusters and molecules, and it will enable new
precision experiments with a broad class of atoms, using the same laser system.
The propagating particles are illuminated by three pulses of a standing
ultraviolet laser beam, which detaches an electron via efficient single
photon-absorption. Optical gratings may have periods as small as 80 nm, leading
to wide diffraction angles for cold atoms and to compact setups even for very
massive clusters. Accounting for the coherent and the incoherent parts of the
particle-light interaction, we show that the combined effect of phase and
amplitude modulation of the matter waves gives rise to a Talbot-Lau-like
interference effect with a characteristic dependence on the pulse delay time.Comment: 25 pages, 5 figure
Pesticide use in banana plantations in Costa Rica-A review of environmental and human exposure, effects and potential risks
Biodiversity is declining on a global scale. Especially tropical ecosystems, containing most of the planetary biodiversity, are at risk. Agricultural monocrop systems contribute to this decline as they replace original hab-itats and depend on extensive use of synthetic pesticides that impact ecosystems. In this review we use large-scale banana production for export purposes in Costa Rica as an example for pesticide impacts, as it is in production for over a century and uses pesticides extensively for more than fifty years. We summarise the research on pesticide exposure, effects and risks for aquatic and terrestrial environment, as well as for human health. We show that exposure to pesticides is high and relatively well-studied for aquatic systems and humans, but hardly any data are available for the terrestrial compartment including adjacent non target ecosystems such as rainforest fragments. Ecological effects are demonstrated on an organismic level for various aquatic species and processes but are not available at the population and community level. For human health studies exposure evaluation is crucial and recognised effects include various types of cancer and neurobiological dysfunctions particularly in children. With the many synthetic pesticides involved in banana production, the focus on insecticides, revealing highest aquatic risks, and partly herbicides should be extended to fungicides, which are applied aerially over larger areas. The risk assessment and regulation of pesticides so far relies on temperate models and test species and is therefore likely underestimating the risk of pesticide use in tropical ecosystems, with crops such as banana. We highlight further research approaches to improve risk assessment and, in parallel, urge to follow other strategies to reduce pesticides use and especially hazardous substances
Critical Phenomena at the Antiferromagnetic Phase Transition of Azurite
We report on high-resolution acoustic, specific-heat and thermal expansion
measurements in the vicinity of the antiferromagnetic phase transition at T_N =
1.88 K on a high-quality single crystal of the natural mineral azurite. A
detailed investigation of the critical contribution to the various quantities
at T_N is presented. The set of critical exponents and amplitude ratios of the
singular contributions above and below the transition indicate that the system
can be reasonably well described by a three-dimensional Heisenberg
antiferromagnet.Comment: 9 pages, 3 figures, proceedings of ICM 2012, JKP
Reconstructing volcanic radiative forcing since 1990, using a comprehensive emission inventory and spatially resolved sulfur injections from satellite data in a chemistry-climate model
This paper presents model simulations of stratospheric aerosols with a focus on explosive volcanic eruptions.
Using various (occultation and limb-based) satellite instruments, providing vertical profiles of sulfur dioxide (SO2) and aerosol extinction, we characterized the chemical and radiative influence of volcanic aerosols for the period between 1990 and 2019.
We established an improved and extended volcanic SO2 emission inventory that includes more than 500 explosive volcanic eruptions reaching the upper troposphere and the stratosphere.
Each perturbation identified was derived from the satellite data and incorporated as a three-dimensional SO2 plume into a chemistry-climate model without the need for additional assumptions about altitude distribution and eruption duration as needed for a “point source” approach.
The simultaneous measurements of SO2 and aerosol extinction by up to four satellite instruments enabled a reliable conversion of extinction measurements into injected SO2.
In the chemistry-climate model, the SO2 from each individual plume was converted into aerosol particles and their optical properties were determined.
Furthermore, the aerosol optical depth (AOD) and the instantaneous radiative forcing on climate were calculated online. Combined with model improvements, the results of the simulations are consistent with the observations of the various satellites.
Slight deviations between the observations and model simulations were found for the large volcanic eruption of Pinatubo in 1991 and cases where simultaneous satellite observations were not unique or too sparse.
Weak- and medium-strength volcanic eruptions captured in satellite data and the Smithsonian database typically inject about 10 to 50 kt SO2 directly into the upper troposphere/lower stratosphere (UTLS) region or the sulfur species are transported via convection and advection. Our results confirm that these relatively minor eruptions, which occur quite frequently, can nevertheless contribute to the stratospheric aerosol layer and are relevant for the Earth's radiation budget.
These minor eruptions cause a total global instantaneous radiative forcing of the order of −0.1 W m−2 at the top of the atmosphere (TOA) compared to a background stratospheric aerosol forcing of about −0.04 W m−2.
Medium-strength eruptions injecting about 400 kt SO2 into the stratosphere or accumulation of consecutive smaller eruptions can lead to a total instantaneous forcing of about −0.3 W m−2. We show that it is critical to include the contribution of the extratropical lowermost stratospheric aerosol in the forcing calculations.</p
Engineering and geological features of soils fundamentals buildings and engineering networks of the Dnipro city
The analysis of engineering and geological properties of soils both in the natural state and under the influence of human economic activity is performed in the work. The researches from the point of view of conditions of construction and operation of buildings and constructions of engineering infrastructure of the city of Dnipro are proved. As a result of the analysis of specific geomorphological zones, specific examples of violations of the operation of buildings on subsidence soils, a number of measures are proposed for maintenance and operation of buildings and structures located in areas composed of subsidence soils, on the example of specific areas exposed to past man-made events. An analytical assessment of the ecological catastrophe on the territory of the Topolya 1 railway in 1997 is provided. The paper considers a principled approach to the principles and conditions of operation of buildings and structures on specific subsidence soils of the city of Dnipro.В роботі виконано аналіз інженерно-геологічних властивостей грунтів як в
природньому стані, так і під впливом господарської діяльності людини. Доведені дослідження з точки зору умов будівництва і експлуатації будівель та споруд інженерної інфрастуктури міста Дніпро. Внаслідок аналізу конкретних геоморфологічних зон, конкретних прикладів порушень умов експлуатації будівель на просідальних грунтах, пропонується ряд заходів по утриманню і експлуатації будівель і споруд, розташованих на територіях, складених просідальними грунтами, на прикладі конкретних районів, які піддавалися в минулому негативним подіям техногенного характреру. Надається аналітична оцінка екологічної катастрофи на території ж/м "Тополя -1" у 1997 році. В роботі розглядається принциповий підхід до принципів і умов експлуатації будівель і споруд на специфічних просідальних грунтах міста Дніпро
Strengths and weaknesses of a new mouse model of thrombosis induced by inferior vena cava stenosis: communication from the SSC of the ISTH
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