15,382 research outputs found
Fine-scale mapping of High Nature Value farmlands: novel approaches to improve the management of rural biodiversity and ecosystem services
High Nature Value farmlands (HNVf) are defined as rural lands characterized by high levels of biodiversity and extensive farming practices. These farmlands are also known to provide important ecosystems services, such as food production, pollination, water purification and landscape recreation. Recently, this concept has been introduced in Rural Development Programmes related to biodiversity preservation in traditional agricultural landscapes. However, there are no specific rules concerning the practical use of the concept, particularly on the identification of potential HNVf areas at a local scale. However, this application becomes important for farmland biodiversity protection in the context of multi-scale agricultural development. We present a novel approach for HNVf mapping, which provides an improved local discrimination of farmlands according to their contribution for the conservation of rural biodiversity and ecosystem services. Our approach is based on a multi-criteria valuation of habitat types based on the national land cover map and agrarian censuses. It is onsidered applicable in other EU countries since comparable datasets are usually available. This methodology is also expected to provide the backbone of a standard, cost-effective methodology for HNVf monitoring, with an emphasis on the impacts of land use change on species, habitats and landscape function
A Bayesian estimate of the CMB-large-scale structure cross-correlation
Evidences for late-time acceleration of the Universe are provided by multiple
probes, such as Type Ia supernovae, the cosmic microwave background (CMB) and
large-scale structure (LSS). In this work, we focus on the integrated
Sachs--Wolfe (ISW) effect, i.e., secondary CMB fluctuations generated by
evolving gravitational potentials due to the transition between, e.g., the
matter and dark energy (DE) dominated phases. Therefore, assuming a flat
universe, DE properties can be inferred from ISW detections. We present a
Bayesian approach to compute the CMB--LSS cross-correlation signal. The method
is based on the estimate of the likelihood for measuring a combined set
consisting of a CMB temperature and a galaxy contrast maps, provided that we
have some information on the statistical properties of the fluctuations
affecting these maps. The likelihood is estimated by a sampling algorithm,
therefore avoiding the computationally demanding techniques of direct
evaluation in either pixel or harmonic space. As local tracers of the matter
distribution at large scales, we used the Two Micron All Sky Survey (2MASS)
galaxy catalog and, for the CMB temperature fluctuations, the ninth-year data
release of the Wilkinson Microwave Anisotropy Probe (WMAP9). The results show a
dominance of cosmic variance over the weak recovered signal, due mainly to the
shallowness of the catalog used, with systematics associated with the sampling
algorithm playing a secondary role as sources of uncertainty. When combined
with other complementary probes, the method presented in this paper is expected
to be a useful tool to late-time acceleration studies in cosmology.Comment: 21 pages, 15 figures, 4 tables. We extended the previous analyses
including WMAP9 Q, V and W channels, besides the ILC map. Updated to match
accepted ApJ versio
Serum leptin levels in overweight children and adolescents
Leptin is an adipocyte-secreted hormone which plays a key role in energy homeostasis. Our aim was to determine the relationship between serum leptin and clinical and biochemical features in overweight children and adolescents. Overweight children and adolescents followed in this Unit with serum leptin ascertained were included. Clinical, biochemical and abdominal ultrasound data were analysed. Statistical analysis was performed by t test, chi2, Pearson's correlation and linear regression. One outlier of serum leptin was excluded to perform correlation and regression. Serum leptin was determined in 357 patients. At the first visit, the mean age was 9.5 (sd 3.2) years and mean BMI z-score was 1.72 (sd 1.34) (girls 1.71 (sd 1.16); boys 1.72 (sd 1.11)). Serum leptin levels were significantly related to: sex (mean: girls 48.0 ng/ml, boys 34.4 ng/ml; P = 0.003); Tanner stage (mean: I-II 37.0 ng/ml, III-V 45.2 ng/ml; P = 0.035); systolic blood pressure (mean: normal 41.3 ng/ml, high 44.0 ng/ml; P = 0.009); BMI z-score (r 0.136; P = 0.010); C-peptide (r 0.17; P = 0.002); insulin (r 0.34; P < 0.001); homeostasis model assessment of insulin resistance (HOMA-IR) (r 0.25; P < 0.001) and aspartate aminotransferase (r - 0.12; P = 0.023). In the multivariate analysis (with leptin as the dependent variable and sex, Tanner stage, BMI z-score, systolic blood pressure, aspartate aminotransferase, C-peptide, insulin and HOMA-IR as independent variables), sex and BMI were determinant factors. The present study in overweight children and adolescents showed that being female and greater BMI were significantly and independently associated with increased serum leptin. In this large cohort other associations with leptin described in the literature can be discharged
Probing quantum fluctuation theorems in engineered reservoirs
Fluctuation Theorems are central in stochastic thermodynamics, as they allow
for quantifying the irreversibility of single trajectories. Although they have
been experimentally checked in the classical regime, a practical demonstration
in the framework of quantum open systems is still to come. Here we propose a
realistic platform to probe fluctuation theorems in the quantum regime. It is
based on an effective two-level system coupled to an engineered reservoir, that
enables the detection of the photons emitted and absorbed by the system. When
the system is coherently driven, a measurable quantum component in the entropy
production is evidenced. We quantify the error due to photon detection
inefficiency, and show that the missing information can be efficiently
corrected, based solely on the detected events. Our findings provide new
insights into how the quantum character of a physical system impacts its
thermodynamic evolution.Comment: 9 pages, 4 figure
Antecipação da adubação nitrogenada de cobertura do arroz de terras altas em sistema plantio direto.
Um experimento de campo está sendo conduzido na Fazenda Capivara da Embrapa Arroz e Feijão com o objetivo de avaliar o efeito da antecipação da adubação nitrogenada de cobertura no desenvolvimento e produtividade de arroz de terras altas (Primavera CL) cultivado em SPD, utilizando diferentes fontes de N
- …