158 research outputs found
Towards a resource-based habitat approach for spatial modelling of vector-borne disease risks
Given the veterinary and public health impact of vector-borne diseases, there is a clear need to assess the suitability of landscapes for the emergence and spread of these diseases. Current approaches for predicting disease risks neglect key features of the landscape as components of the functional habitat of vectors or hosts, and hence of the pathogen. Empirical–statistical methods do not explicitly incorporate biological mechanisms, whereas current mechanistic models are rarely spatially explicit; both methods ignore the way animals use the landscape (i.e. movement ecology). We argue that applying a functional concept for habitat, i.e. the resource-based habitat concept (RBHC), can solve these issues. The RBHC offers a framework to identify systematically the different ecological resources that are necessary for the completion of the transmission cycle and to relate these resources to (combinations of) landscape features and other environmental factors. The potential of the RBHC as a framework for identifying suitable habitats for vector-borne pathogens is explored and illustrated with the case of bluetongue virus, a midge-transmitted virus affecting ruminants. The concept facilitates the study of functional habitats of the interacting species (vectors as well as hosts) and provides new insight into spatial and temporal variation in transmission opportunities and exposure that ultimately determine disease risks. It may help to identify knowledge gaps and control options arising from changes in the spatial configuration of key resources across the landscape. The RBHC framework may act as a bridge between existing mechanistic and statistical modelling approaches
Constraining the optical emission from the double pulsar system J0737-3039
We present the first optical observations of the unique system J0737-3039
(composed of two pulsars, hereafter PSR-A and PSR-B). Ultra-deep optical
observations, performed with the High Resolution Camera of the Advanced Camera
for Surveys on board the Hubble Space Telescope could not detect any optical
emission from the system down to m_F435W=27.0 and m_F606W=28.3. The estimated
optical flux limits are used to constrain the three-component (two thermal and
one non-thermal) model recently proposed to reproduce the XMM-Newton X-ray
spectrum. They suggest the presence of a break at low energies in the
non-thermal power law component of PSR-A and are compatible with the expected
black-body emission from the PSR-B surface. The corresponding efficiency of the
optical emission from PSR-A's magnetosphere would be comparable to that of
other Myr-old pulsars, thus suggesting that this parameter may not dramatically
evolve over a time-scale of a few Myr.Comment: 16 pages, 3 figures, ApJ accepte
Genotypic distinctions of variability of biochemical composition of fruits of Vacciniaceae species under conditions of Belarus
Result of research of quantitative characteristics of biochemical composition of fruits of 30 taxons of 3 Vacciniaceae species (such as V. corymbosum L. (highbush blueberry), V. vitis-idaea L. (lingonberry) and Oxycoccus macrocarpus (Ait.) Pers. (cranberry)) inter-specific distinctions of a degree of stability of its separate components to complex influence of meteorological factors are revealed by 32 parameters (traits) describing the contents in fruits of some organic acids, carbohydrates, phenolic compounds, terpenoids and major mineral elements are presented. The cultivars possessing by the greatest and accordingly by the least levels of dependence on abiotic factors are identified
Patients with chronic myeloid leukemia treated with imatinib who showed the appearance of clonal cytogenetic abnormalities in Philadelphia chromosome-negative cells
Specific features of designing a database for neuro-oncological 3D MRI images to be used in training artificial intelligence
The research was aimed at analyzing current approaches to the organization and design methodology of visualization database built on the basis of computer vision. Such approaches are necessary for effective development of diagnostic systems using artificial intelligence (AI). A training data set of high quality is a mandatory prerequisite for that. Material and methods. The paper presents the technology for designing an annotated database (SBT Dataset) that contains about 1000 clinical cases based on the archived data acquired by the Federal Neurosurgical Center, Novosibirsk, Russia including data on patients with astrocytoma, glioblastoma, meningioma, neurinoma, and patients with metastases of somatic tumors. Each case is represented by a preoperative MRI. The Results and Discussion. The dataset was built (SBT Dataset) containing segmented 3D MRI images of 5 types of brain tumors with 991 verified observations. Each case is represented by four MRI sequences T1-WI, T1C (with Gd-contrast), T2-WI and T2-FLAIR with histological and histochemical postoperative confirmation. Tumors segmentation with verification of the tumor core elements boundaries and perifocal edema was approved by two certified experienced neuroradiologists. Conclusion. The database built during the research is comparable in its volume and quality (verification level) with the state-of-the-art databases. The methodological approaches proposed in this paper were focused on designing the high-quality medical computer vision systems. The database was used to create artificial intelligence systems with the “physician assistant” functions for preoperative MRI diagnostics in neurosurgery
Температурная зависимость ширины запрещенной зоны монокристаллов AgIn7S11
AgIn7S11 single crystals are herein grown by the vertical Bridgman method. The composition of the obtained single crystals is determined by X-ray microprobe analysis as well as the crystal structure – by X-ray diffraction analysis. It is shown that the obtained single crystals are crystallized in the cubic spinel structure. Using transmission spectra in the tem- perature range 10–320 K we determined the band gap of these single crystals and plotted its temperature dependence. This dependence is similar to that of the majority of semiconductor materials, namely, Eg increases with decreasing the tempera- ture. We showed the agreement of the calculated and experimental values.Вертикальным методом Бриджмена выращены монокристаллы AgIn7S11. Методом рентгеноспектрального анализа определен их состав, рентгеновским методом – кристаллическая структура. Показано, что полученные монокристаллы кристаллизуются в кубической структуре шпинели. По спектрам пропускания в интервале температур 10–320 К определена ширина запрещенной зоны указанных монокристаллов и построена ее температурная зависимость. Данная зависимость имеет вид, характерный для большинства полупроводниковых материалов: с понижением температуры Eg возрастает. Показано, что расчетные и экспериментальные величины согласуются между собой
SUBTYPES OF MATURE T AND NK CELL LYMPHOMAS ACCORDING TO 2016 WHO CLASSIFICATION. PRELIMINARY REPORT OF THE INTERNATIONAL PROSPECTIVE T‐CELL PROJECT 2.0
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The UDF05 Follow-up of the HUDF: I. The Faint-End Slope of the Lyman-Break Galaxy Population at zeta approx. 5
We present the UDF05 project, a HST Large Program of deep ACS (F606W, F775W, F850LP, and NICMOS (Fll0W, Fl60W) imaging of three fields, two of which coincide with the NICP1-4 NICMOS parallel observations of the Hubble Ultra Deep Field (HUDF). In this first paper we use the ACS data for the NICP12 field, as well as the original HUDF ACS data, to measure the UV Luminosity Function (LF) of z approximately 5 Lyman Break Galaxies (LBGs) down to very faint levels. Specifically, based on a V - i, i - z selection criterion, we identify a sample of 101 and 133 candidate z approximately 5 galaxies down to z(sub 850) = 28.5 and 29.25 magnitudes in the NICP12 field and in the HUDF, respectively. Using an extensive set of Monte Carlo simulations we derive corrections for observational biases and selection effects, and construct the rest-frame 1400 Angstroms LBG LF over the range M(sub 1400) = [-22.2, -17.1], i.e. down to approximately 0.04 L(sub *) at z = 5. We show that: (i) Different assumptions for the SED distribution of the LBG population, dust properties and intergalactic absorption result in a 25% variation in the number density of LBGs at z = 5 (ii) Under consistent assumptions for dust properties and intergalactic absorption, the HUDF is about 30% under-dense in z = 5 LBGs relative to the NICP12 field, a variation which is well explained by cosmic variance; (iii) The faint-end slope of the LF is independent of the specific assumptions for the input physical parameters, and has a value of alpha approximately -1.6, similar to the faint-end slope of the LF that has been measured for LBGs at z = 3 and z = 6. Our study therefore supports no variation in the faint-end of the LBG LF over the whole redshift range z = 3 to z = 6. The comparison with theoretical predictions suggests that (a,) the majority of the stars in the z = 5 LBG population are produced with a Top-Heavy IMF in merger-driven starbursts, and that (b) possibly, either the fraction of stellar mass produced in starburst, or the fraction of high mass stars in the bursts is increased towards the bright end of the LF
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