767 research outputs found
Pyaneti: a fast and powerful software suite for multi-planet radial velocity and transit fitting
Transiting exoplanet parameter estimation from time-series photometry and
Doppler spectroscopy is fundamental to study planets' internal structures and
compositions. Here we present the code pyaneti, a powerful and user-friendly
software suite to perform multi-planet radial velocity and transit data
fitting. The code uses a Bayesian approach combined with an MCMC sampling to
estimate the parameters of planetary systems. We combine the numerical
efficiency of FORTRAN, the versatility of PYTHON, and the parallelization of
OpenMP to make pyaneti a fast and easy to use code. The package is freely
available at https://github.com/oscaribv/pyaneti.Comment: 15 pages, 6 figures, 2 tables. Accepted for publication in MNRA
Ab initio calculation of the electromagnetic and neutral-weak response functions of 4He and 12C
Precise measurement of neutrino oscillations, and hence the determination of
their masses demands a quantitative understanding of neutrino-nucleus
interactions. To this aim, two-body meson-exchange currents have to be
accounted for along within realistic models of nuclear dynamics. We summarize
our progresses towards the construction of a consistent framework, based on
quantum Monte Carlo methods and on the spectral function approach, that can be
exploited to accurately describe neutrino interactions with atomic nuclei over
the broad kinematical region covered by neutrino experiments.Comment: 8 pages, 4 figure, Proceedings of the 21st International Conference
on Few-Body Problems in Physics, Chicago, Illinois, US
Non-Coexistence of Infinite Clusters in Two-Dimensional Dependent Site Percolation
This paper presents three results on dependent site percolation on the square
lattice. First, there exists no positively associated probability measure on
{0,1}^{Z^2} with the following properties: a) a single infinite 0cluster exists
almost surely, b) at most one infinite 1*cluster exists almost surely, c) some
probabilities regarding 1*clusters are bounded away from zero. Second, we show
that coexistence of an infinite 1*cluster and an infinite 0cluster is almost
surely impossible when the underlying probability measure is ergodic with
respect to translations, positively associated, and satisfies the finite energy
condition. The third result analyses the typical structure of infinite clusters
of both types in the absence of positive association. Namely, under a slightly
sharpened finite energy condition, the existence of infinitely many disjoint
infinite self-avoiding 1*paths follows from the existence of an infinite
1*cluster. The same holds with respect to 0paths and 0clusters.Comment: 17 pages, 1 figur
Biomimetic Calcium-Silicate Cements Support Differentiation Of Human Orofacial Mesenchymal Stem Cells
Introduction Human orofacial bone mesenchymal stem cells (OFMSCs) from maxilla and mandible have robust osteogenic regenerative properties based on our previous reports that demonstrate phenotypic and functional differences between jaw and axial bone mesenchymal stem cells in same individuals. Furthermore, a combination of OFMSCs with bioactive calcium-releasing cements can potentially improve OFMSC multi-lineage differentiation capacity, but biocompatibility of calcium silicate cements with OFMSCs is still unclear. We tested the hypothesis that material extracts of calcium-releasing calcium-silicate cements support biomimetic microenvironment for survival and differentiation of human OFMSCs. Methods Two experimental calcium-silicate cements 1) calcium-silicate mineral powder (wTC) containing di- and tricalcium-silicate, calcium sulphate, and calcium chloride and 2) wTC doped with alpha-tricalcium phosphate (wTC-αTCP) were designed and prepared. Cement setting times were assessed by Gilmore needles, ability to release calcium and hydroxyl ions was assessed by potentiometric methods and OFMSC attachment to calcium-silicate discs was assessed. Calcium-silicate material extracts were tested for ability to support OFMSCs survival and in vitro/in vivo differentiation. Results Fewer OFMSCs attached to calcium-silicate discs relative to tissue culture plastic (p=0.001). Extracts of calcium-silicate cements sustained OFMSC survival, maintained steady state levels of vascular cell adhesion molecule-1, alkaline phosphatase and bone sialoprotein while upregulating their respective gene transcripts. Adipogenic and in vivo bone regenerative capacities of OFMSCs were also unaffected by calcium-silicate extracts. Conclusions Ion-releasing calcium-silicate cements support a biomimetic microenvironment conducive to survival and differentiation of OFMSCs. Combination of OFMSCs and calcium-silicate cement can potentially promote tissue regeneration in periapical bone defects
Simulation of maize irrigation requirements at the regional scale : comparison between results obtained with measured and FAO-56 crop coefficient
The FAO-56 \u201csingle crop coefficient\u201d or \u201cdouble crop coefficient\u201d approaches are the most recommended and widely adopted procedures for the estimation of crop irrigation requirements. In these methods crop evapotranspiration in well-watered conditions is calculated by multiplying the grass reference evapotranspiration ET0 determined by the Penman-Monteith FAO-56 equation and a crop coefficient Kc depending on the crop type and its growing stage. In particular, the \u201cdouble crop coefficient\u201d allows the separation of soil evaporation and crop transpiration, splitting Kc in two different terms: a basal crop coefficient Kcb and a soil evaporation coefficient Ke.
Many authors in the last fifteen years showed that the FAO Kc and Kcb tabulated coefficients, even if adjusted using the specific procedure based on local meteorological, irrigation and crop data suggested by FAO-56, tend to underestimate the observed crop coefficients in arid and semi-arid environments, while an overestimation often occurs for humid and semi-humid regions. In the literature differences up to \ub140% especially during the middle growth cycle are reported, mainly due to the complexity of the crop coefficient which actually integrates several physical and biological factors.
The purpose of our research was to measure the Kc pattern for maize grown in the Lombardy Region (Northern Italy) and to evaluate the difference in crop irrigation requirements at a regional scale considering the measured Kc instead of the FAO tabulated values using a spatially distributed hydrological model.
Kc was calculated for two experimental maize fields for years 2006, 2010 and 2011 as the ratio between actual crop evapotranspiration (ET) in well watered conditions and ET0. ET was measured using eddy-covariance technique while ET0 was determined from agro-meteorological data registered by the two standard meteo stations closest to the experimental areas. The second step of the research was achieved by using the distributed model IDRAGRA, which allows the computation of crop irrigation requirements on the basis of the \u201cdouble crop coefficient\u201d FAO-56 approach. This model has been adopted in various projects carried out in collaboration with the Lombardia Regional Authority. In the simulations, the spatial variability of soil types and the spatial and temporal variability of meteorological inputs was taken into account.
Observed Kc and Kcb patterns showed that the mid-season stage tabulated values overestimate the observed values by around 18%; if adjustments with local data are considered for FAO crop coefficients, the average overestimation reduces to 14%. Results of the spatially distributed model application illustrated the effect of this overestimation on the crop irrigation requirements over the regional territory. Considerations on its repercussion in term of water resources planning were finally made
Performance of evapotranspiration models for a maize agro-ecosystem : from bare soil to maximum coverage in irrigated and rainfed conditions
To assure an efficient management and planning of irrigation water resources, an accurate computation of actual evapotranspiration (ET) from cropped surfaces is needed. ET models can be classified in two categories: \u201cdirect\u201d methods, based on the original Penman-Monteith (P-M) equation, in which the canopy resistance rc is modelled, and \u201cindirect\u201d methods, based on the calculation of ET for a well-watered reference grass (ET0) with constant rc multiplied by a crop coefficient that represents the relative rate of ET from a specific crop and condition to that of the reference.
This last procedure, standardized by FAO-56 bulletin, is the most widely adopted for the estimation of ET. However, in literature there are evidences that direct methods (P-M models with rc modelled) are still the most performing. In fact, for indirect methods, errors introduced by the calculation of ET0 considering a constant rc for reference crop and by the estimation of the crop coefficient, which actually integrates several physical and biological factors, can be relevant.
This study evaluates the performance of different models for the estimation of ET for a maize agro-ecosystem in the Padana Plain (Northern Italy). The following models have been considered: 1) the \u201cone-step\u201d P-M model using a constant daily canopy resistance following the classical Monteith approach; 2) the \u201cone-step\u201d P-M model using a variable canopy resistance based on the approach of Katerji-Perrier, in which rc is calculated as a function of climate variables, aerodynamic resistance, vegetation type and its water status; 3) the \u201ctwo-step\u201d Shuttleworth model as updated by Shuttleworth and Gurney (1990), which combines one-dimensional models of crop transpiration and of soil evaporation, where canopy and soil surface resistances regulate the heat and mass transfer at the plant and soil surfaces, and aerodynamic resistances regulate those between these surfaces and the atmospheric boundary layer; 5) the indirect \u201csingle crop coefficient\u201d method proposed by FAO-56; 6) the indirect \u201cdouble crop coefficient\u201d method proposed by FAO-56, which allows the separation of soil evaporation and crop transpiration.
Latent heat fluxes measured in 2006, 2010 and 2011 in an experimental maize field by eddy-covariance are used to evaluate the models accuracy. Crop, soil and meteo data monitored contextually are used for different models implementation. Data from the closest standard agro-meteorological station are adopted in the ET0 calculation for indirect methods.
Results of this work confirm what reported by other authors in the literature, demonstrating that the calculation of crop evapotranspiration by direct method is more accurate than the use of indirect methods for both irrigated (2006, 2010) and rainfed (2011) conditions
Ab Initio Calculation of the Electromagnetic and Neutral Weak Response Functions of \u3csup\u3e4\u3c/sup\u3eHe and \u3csup\u3e12\u3c/sup\u3eC
Precise measurement of neutrino oscillations, and hence the determination of their masses demands a quantitative understanding of neutrino-nucleus interactions. To this aim, two-body meson-exchange currents have to be accounted for along within realistic models of nuclear dynamics. We summarize our progresses towards the construction of a consistent framework, based on quantum Monte Carlo methods and on the spectral function approach, that can be exploited to accurately describe neutrino interactions with atomic nuclei over the broad kinematical region covered by neutrino experiments
A case of morgagnian cataract mimicking an iris tumor
Purpose: To report, with the aid of original imaging, an unusual differential diagnosis of an iris tumor. Observations: A 60-year-old Caucasian man visited our clinic with a large amelanotic iris mass in the left eye in the absence of concomitant extraocular inflammation or neoplastic evidence. The patient reported an ocular trauma caused by a wire 5 years prior to his visit, which resolved after a short course of antibiotic eye drops. Orbital magnetic resonance imaging with contrast enhancement was consistent with an iris tumor; ultrasound biomicroscopy indicated a semi-solid, mid-stromal iris formation continuous with the lens. Surgical inspection was performed. Surgery showed the presence of a hypermature cataract with a fine break in the anterior capsule of the lens covered by the iris surface. The liquefied cortex infiltrated the iris without diffusing into the aqueous humor. Conclusions and Importance: A so-called morgagnian cataract developed, likely following a penetrating ocular wound. The progressive, slow infiltration of the iris stroma by the crystalline matrix mimicked the appearance of an amelanotic iris tumor
Sustainable water use for rice agro-ecosystems in northern Italy
I n the Mediterranean basin, rice is cultivated over an area of 1,300,000 hectares. The most
important rice-producing countries are Italy and Spain in Europe (72% of the EU production;
345,000 ha), and Egypt and Turkey among the extra-EU countries (almost totality of the
production; 789,000 ha). Traditionally, rice is grown under continuous flooding; thus, it requires
much more irrigation than non-ponded crops. The MEDWATERICE project (PRIMA-Section 2-2018;
https://www.medwaterice.org/) aims at exploring sustainability of innovative rice irrigation
management solutions, in order to reduce rice water consumption and environmental impacts,
and to extend rice cultivation outside of traditional paddy areas to meet the escalating demand.
Within the MEDWATERICE project, irrigation management options to address the main site-specific
problems are being tested for each rice areas involved in the project (IT, ES, PT, EG, TR). Case
studies are being conducted in pilot farms, with the involvement of Stake-Holder Panels (SHPs) in
each country. Data collected at the farm level will be extrapolated to the irrigation district level, to
support water management decisions and policies. Moreover, indicators for quantitative
assessment of environmental, economic and social sustainability of the irrigation options will be
defined.
This work illustrates the first year of results for the Italian Case Study (Lomellina area, Pavia) at the
pilot farm scale. This area is characterized by a growing water scarcity in drought years in many
districts. Within the farm managed by the National Rice Research Center (CRR), in the agricultural
season 2019 the experimentation was conducted in six plots of about 20 m x 80 m each, with two
replicates for each of the following water regimes: i) water-seeded rice with continuous flooding
(WFL), ii) dry-seeded rice with continuous flooding from the 3-4 leaf stage (DFL), and iii) water
seeded-rice with alternate wetting and drying from fertilization at the tillering stage (AWD). One
out of the two replicates of each treatment was instrumented with: water inflow and outflow
meters, set of piezometers, set of tensiometers and water tubes for the irrigation management in
the AWD plots. A soil survey was conducted before the agricultural season (EMI sensor and
physico-chemical analysis of soil samples). Periodic measurements of crop biometric parameters
(LAI, crop height, crop rooting depth) were performed. Moreover, nutrients (TN, NO3, PO4, K) and
two widely used pesticides (Sirtaki \u2013 a.i. Clomazone; Tripion E \u2013 a.i. MCPA) were measured in
irrigation water (inflow and outflow), groundwater, and porous cups installed at two soil depths
(20 and 70 cm, above and below the plough pan). Finally, rice grain yields and quality (As and Cd in the grain) were determined. First results in terms of cumulative water balance components
(rainfall, irrigation inflow and outflow, difference in soil and ponding water storage,
evapotranspiration, net percolation), water application efficiency (evapotranspiration over net
water input), and water productivity (grain production over net water input), will be presented and
discussed. Results of a 1D Richard-equation-based numerical simulation model applied to
generalize results obtained under the different irrigation regimes will be moreover illustrated
Tecendo novos arranjos sociais: um estudo dos impactos de um empreendimento solidário na Comunidade Rural Córrego do Açude de Ituiutaba/MG
A emergência e a legitimação dos empreendimentos solidários vêm ocorrendo em diversos setores, tais como educação, saúde, transporte, todos com o objetivo de promover ações de interesse geral. A economia solidária e a economia social, conceitos que surgem no contexto europeu, particularmente, francês, fundamentam-se em experiências de iniciativas da comunidade capazes de gerar formas alternativas de ação pública, não se constituindo nem em uma forma de organização capitalista, nem em uma ação do Estado. Este artigo analisa a influência desses novos arranjos socioprodutivos no contexto da economia solidária que contribuem para a construção do processo de territorialização de uma comunidade sob o ponto de vista de sua identidade, de sua história e de suas relações sociais, conforme alguns parâmetros de avaliação presentes em projetos de economia solidária. Trata-se de uma pesquisa de natureza qualitativa com uso de recursos quantitativos. Utiliza-se de um estudo de caso da comunidade rural Córrego do Açude de Ituiutaba, Minas Gerais, a título de ilustração. A coleta de dados foi realizada por meio de entrevistas com membros da comunidade e documentos disponibilizados pela mesma. A partir da análise de quatro categorias, os resultados apontam que os fundamentos da economia solidária influenciam no território quanto aos aspectos de sua história, de suas relações sociais e de sua identidade
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