693 research outputs found
Seasonal changes in dry matter yield from Karst pastures as influenced by morphoclimatic features
Pastures are strongly affected by local environmental variables in terms of their species richness, plant composition and herbage production. A multi-site monitoring study was conducted over three years to investigate the influence of morphoclimatic factors on the seasonal variations in dry matter (DM) yield from Karst pastures. Seven sites located on the Italian and Slovenian Karst regions were investigated that differed in terms of their geological and geomorphological features, as well as their soil types. At each site, the daily DM yield (kg ha-1 d-1) was determined using Corral-Fenlon method which permits to simulate herbage utilization from grazing herds. The morphoclimatic features were also analysed, with the aim to evaluate the link between seasonal DM yield and geomorphological and environmental factors. Generalized non-linear mixed models were built to study the observed seasonal variations in DM yield, using day of the year (DOY), growing degree days (GDD), and cumulative rainfall. Furthermore, environmental descriptors were included in the model in order to evaluate their effects on DM yield. The seasonal variations in yield showed two growing periods (spring and late summer), which were described by Gaussian curves. For the spring growing period, the model improved when the interaction between soil granulometry and growing degree days corresponding to the curve peak was taken into account. This confirms the influence of soil type and air temperature on pasture yield. For the late summer growing period, the interaction between the sand classes and the number of rainy days from the beginning of the period to the peak of the curve improved the model. The curve parameters of our models are correlated with environmental descriptors depending on the lithology and particle size of soils. The results are essential for the optimization of pasture management and avoiding degradation due to over- or under-grazing
SNOWFALL ANALYSIS OVER PENINSULAR ITALY IN RELATIONSHIP TO THE DIFFERENT TYPES OF SYNOPTIC CIRCULATION: FIRST RESULTS
The time series of snow data for a sample of Italian meteorological stations have been analyzed taking into account, for the time series, an acceptable continuity and quality of meteorological data. The data set is that of the Italian Meteorological Service (UGM), and refer to the period 1982â2004. The Slovenian station of Kredarica, located in the Julian Alps, has been added for convenience.
The study is composed of two different parts:
- Climatologic analysis of the snow parameters during the last 20 years. In particular, the height of the fresh snow and the number of days with permanence of snow at the ground have been analyzed.
- Evidence of the synoptic situations in which snowfalls are observed with at least a thickness of 10 cm in at least a third of the total number of analyzed stations in Central, Southern and insular Ital
A new early warning drought index for Ethiopia
Abstract
This study investigates the occurrence of droughts in the Dire Dawa area of eastern Ethiopia. A new index based on the rainfall delay (Rd) with respect to the expected onset (and traditional) seeding time and other indices, i.e., the aridity index and the Z-score, alternatives to the Standard Precipitation Index (SPI), are used to test the validity of the new Rd index in identifying severe droughts extending back to 1955. Although only data of rain gauges located in the district of Dire Dawa were used, they proved, albeit with different accuracies, able to identify nation-wide droughts
Analysis of recent meteorological configurations responsible for substantial snowfalls in the Trentine sector of the Adige valley bottom (eastern italian Alps).
Aim of this presentation is to analyse the synoptic conditions favourable to snowfall with more than 10 cm fresh snow cover in the bottom of the Trentine sector of the Adige Valley. Following the abundant and reiterated snowfalls in the study area during the 2005-2006 winter season and the many discomforts to the population and mainly to the road traffic, an accurate study of such events resulted necessary for a reliable forecast. The valley orientation in a NNE-SSW direction lets the Mediterranean warm-humid air masses to get in as far as the main headwater divide (Brenner Pass) and to make its climate relatively mild. Moreover, such humid air inflows bring mean annual precipitation of about 800-1000 mm that gradually decreses from the lower valley mouth to the main divide. The precipitation regime consists of rainfalls in spring and autumn whereas a strong absolute minimum occurs between December and Febraury when snowfalls are more likely on the valley floor. In fact, the vally is annually subjected to warm advection snowfalls, though infrequent and scarce, between November and mid April. The study area is about 80 km long with elevation ranging from 130 and 230 m a.s.l. All the snowfall events observed from 1980 to 2006 were analysed by using the data of the Civil Protection Authority of Trento Province, i.e. Trento Roncafort (194 n a.s.l.), Trento Laste (312 m a.s.l.), Rovereto (203 m a.s.l.) and Ala (197 m a.s.l.) meteo stations. Through the study and analysis of ground and at the 500 hPa geopotential meteo maps, satellite images, thermodynamic diagrams of the nearest sounding stations and the data of the nivometeorological stations, the synoptic types that characterised the snowfalls were studied and classified and a clusterisation was made. For each of the synoptic types defined the conditions for a quantification of the mean characteristic meteo parameters were anlysed in order to obtain a reliable forecast of intense snowfalls on the valley bottom
SNOWFALL ANALYSIS OVER PENINSULAR ITALY IN RELATIONSHIP TO THE DIFFERENT TYPES OF SYNOPTIC CIRCULATION: FIRST RESULTS
The time series of snow data for a sample of Italian meteorological stations have been analyzed taking into account, for the time series, an acceptable continuity and quality of meteorological data. The data set is that of the Italian Meteorological Service (UGM), and refer to the period 1982â2004. The Slovenian station of Kredarica, located in the Julian Alps, has been added for convenience.
The study is composed of two different parts:
- Climatologic analysis of the snow parameters during the last 20 years. In particular, the height of the fresh snow and the number of days with permanence of snow at the ground have been analyzed.
- Evidence of the synoptic situations in which snowfalls are observed with at least a thickness of 10 cm in at least a third of the total number of analyzed stations in Central, Southern and insular Ital
Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires
The production of tt⟠, W+bb⟠and W+cc⟠is studied in the forward region of protonâproton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fbâ1 . The W bosons are reconstructed in the decays WââÎœ , where â denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of , and is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 0.02 \mbox{fb}^{-1}. The bosons are reconstructed in the decays , where denotes muon or electron, while the and quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
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