Search results for "Planeta"
showing 10 items of 5577 documents
The morphological types of galaxies in the Local Supercluster
2014
AbstractOn the basis of the Hyper – Leda Catalogue HyperLeda 8293 galaxies with heliocentric radial velocities below 2500 km s-1 were selected; 4570 had known morphological types (4366 had calculated b/a ratio). We checked the frequency of the distribution of various types in the LSC, finding spirals and irregulars most numerous, in accordance with expectations. The axial ratio of galaxy diameters of various types was studied, and the dependence of this parameter on the morphological type was noted.
Fire frequency during the Holocene in central Latvia, northeastern Europe
2021
Fire is today a pan-European issue and is expected to be more salient because of climate and land use changes. Even though natural and anthropogenic fires have shaped forest composition and landscape characteristics since the last glacial retreat from northeastern Europe, fire frequency is an understudied topic. To address this issue, we analysed macroscopic charcoal (>160 μm) from two sediment sequences located in the central and littoral parts of Lake Bricu (central Latvia) revealing the fire frequency during the Holocene. The chronology of the analysed sediment sequences is based on spheroidal fly-ash carbonaceous particles and accelerator mass spectrometry radiocarbon dating. Macroscop…
Foreword for the thematic volume of the 8ISCPP. Recent advances in present and past cephalopod studies.
2012
3 pages, éditorial.; International audience
Prediction of soil texture distributions using VNIR-SWIR reflectance spectroscopy
2013
Abstract Reflectance spectroscopy provides an alternate method to non-destructively characterize key soil properties. Different approaches, including chemometrics techniques or specific absorption features, have been proposed to estimate soil properties from visible and near-infrared (VNIR, 400-1200 nm) and shortwave infrared (SWIR, 1200-2500 nm) reflectance domains. The main goal of this study was to test the performance of two distinct methods for soil texture estimation by VNIR-SWIR reflectance measurements: i) the Continuum Removal (CR) technique that was used to correlate specific spectral absorption features with clay, silt and sand content, and ii) the Partial Least-Squares Regressio…
Policy to support digitalisation of industries in various regional settings. A conceptual discussion
2022
The purpose of the article is to analyse regions’ varying preconditions for digitalisation of industry and, on that basis, discuss regionally tailored policy strategies to stimulate digitalisation. Building on both regional innovation system and asset modification approaches, the authors suggest a theoretical framework that identifies regions’ potential for digitalisation from their stock of relevant assets at the firm and innovation system level. The analysis identifies four types of regions with different preconditions for supporting digitalisation of industries. This in turn provides the foundation for a discussion of the role of actor-based and system-based policy strategies to support …
A global perspective on the climate‐driven growth synchrony of neighbouring trees
2020
2 .pdf files: File 1. Author's article final version, Post-Print (19 Pags.- 4 Figs.- 2 Tabls.). File 2. Supplementary Materials (3 Figs.- 2 Tabls.- 1 Model Equation).
On the maximum efficiency of the propeller mass-ejection mechanism
2007
Aims. We derive simple estimates of the maximum efficiency with which matter can be ejected by the propeller mechanism in disk-fed, rotating magnetic neutron stars. Some binary evolution scenarios envisage that this mechanism is responsible for expelling to infinity the mass inflowing at a low rate from the companion star, therefore limiting the total amount of mass that can be accreted by the neutron star. Methods. We demonstrate that, for typical neutron star parameters, a maximum of ��_{pro} < 5.7 (P_{-3})^{1/3} times more matter than accreted can be expelled through the propeller mechanism at the expenses of the neutron star rotational energy (P_{-3} is the NS spin period in unit of …
Unveiling the environment and faint features of the isolated galaxy CIG 96 with deep optical and HI observations
2018
Context. Asymmetries in atomic hydrogen (HI) in galaxies are often caused by the interaction with close companions, making isolated galaxies an ideal framework to study secular evolution. The AMIGA project has demonstrated that isolated galaxies show the lowest level of asymmetry in their HI integrated profiles compared to even field galaxies, yet some present significant asymmetries. CIG 96 (NGC 864) is a representative case reaching a 16% level. Aims. Our aim is to investigate the HI asymmetries of the spiral galaxy CIG 96 and what processes have triggered the star-forming regions observed in the XUV pseudo-ring. Methods. We performed deep optical observations at CAHA1.23m, CAHA2.2m and V…
Measurements of the branching fractions of $\psi(3686)\rightarrow\bar{\Sigma}^{0}\Lambda+c.c.$ and $\chi_{cJ (J = 0,1,2)} \rightarrow \Lambda \bar{\L…
2021
Based on $4.481\times10^8$ $\psi(3686)$ events collected with the BESIII detector at BEPCII, the branching fraction of the isospin violating decay $\psi(3686)\rightarrow\bar{\Sigma}^{0}\Lambda+c.c.$ is measured to be $(1.60 \pm 0.31 \pm 0.13~\pm~0.58) \times 10^{-6}$, where the first uncertainty is statistical, the second is systematic, and the third is the uncertainty arising from interference with the continuum. This result is significantly smaller than the measurement based on CLEO-c data sets. The decays $\chi_{cJ} \rightarrow\Lambda\bar{\Lambda}$ are measured via $\psi(3686)\rightarrow\gamma\chi_{cJ}$, and the branching fractions are determined to be $\mathcal{B}\left(\chi_{c0}\rightar…
PLANETS AROUND LOW-MASS STARS AND STELLAR ACTIVITY EFFECTS
In the last years the field of exoplanet research has focused its interest in M dwarfs. These stars have became the favourite targets in radial velocity surveys, specially when looking for small planets in the habitable zones of their parent stars. Not only for being the M dwarfs the most common objects in our Galaxy also because the Doppler signals due to small planets orbiting around them are larger and more easily detectable than those around FGK stars. However, stellar magnetic activity and rotation affect the measured radial velocities as surface inhomogeneities rotating with the stellar surface can cause periodic changes in the spectral line centroid. Disentangle these stellar activit…