292 research outputs found
Droughts: recurrence, classification and distribution in the Argentina Pampas
Las sequías, fenómeno de alta frecuencia en la Región Pampeana (Argentina), se estudian a través de un índice agrometeorológico derivado del balance de agua del suelo, con lo que se presenta un aporte diferente a la bibliografía del tema. Se considera como índice de los eventos, el valor anual del déficit de agua en el suelo. Ellos tienen lugar casi todos los años, si no en la totalidad del territorio, en algún área y espacio temporal. Las consiguientes consecuencias son diversas en su gravedad, pero siempre tienen impactos socioeconómicos. La evolución y distribución de los sucesos acaecidos se analizan y se realiza la correspondiente climatología. En el estudio se han utilizado datos diarios de precipitación del Servicio Meteorológico Nacional del período 1950 – 2010; evapotranspiración potencial media diaria según la fórmula de Penman-Monteith; balance de agua en el suelo considerando las características del suelo obtenidas «in situ»; y la aplicación de los tests estadísticos no paramétricos Mann-Kendall y Sen. Las series anuales del índice agrometeorológico se emplean para clasificar de la severidad de los eventos en leves, moderados, severos y fuertes y se estudia la tendencia para cada localidad y diferentes lapsos de tiempo. Las sequías presentan tendencias decrecientes durante los períodos de sesenta y un años (1950 - 2010) y de cincuenta años (1961 - 2010) en casi todas las estaciones analizadas.Droughts, phenomenon of high frequency in Pampean Region (Argentina) are studied by means of an agroclimatic index derived from soil water balance, so a different contribution is presented to the subject bibliography. The annual value of soil water deficit is considered as index of the events. They take place almost every year, if not in the whole territory, in some area and temporal space. The resulting consequences are varied in severity, but always have socioeconomic impacts. The evolution and distribution of the events are analyzed and the corresponding climatology is done. There were used daily precipitation data from the National Meteorological Service for the period 1950 - 2010, mean daily potential evapotranspiration according Penman-Monteith formula, soil water balance considering soil characteristics obtained «in situ» and with the application of Mann-Kendall and Sen non parametric tests. The data series of agroclimatic index values are employed to classified the events severity in mild, moderate, severe and extreme and the trend for each station and different period of time are studied. The annual soil water deficit values are employed as index of the severity classification. The quantity of mild, moderate, severe and extreme events are obtained and the trend for different time periods. Decreasing trends are obtained for the periods 1950 - 2010 and 1961 - 2010. Droughts present decreasing trend for the period of sixty one years (1950 - 2010) and fifty years (1961 - 2010) in almost analyzed stations.Fil: Scarpati, Olga Eugenia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Capriolo, Alberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentin
Modeling the Distribution of Agricultural Drought by Means of Soil
The extreme hydrologic events in Buenos Aires province (Argentina) had been a constant in its social - economic development. Their impacts mainly over the agriculture have been studied with different scales and point of views. In spite of that, there is a lack of studies of their temporal and spatial distribution in Argentina. Drought is initiated by a reduction in precipitation. The time requires for a lack of rainfall to create a significant deficit in the supplies is variable and could vary from a few weeks to several years. This paper studies the soil water deficit from 1969 to 2008 in the whole Buenos Aires province (307,571 km2) which is divided in 16 sectors according its basins (National Water Resources) and with soil water balance using soil data obtained “in situ”. It was performed using the evapotranspitation formula of Penman - Monteith and considering the soil water constants: Field Capacity, Soil Water Moisture and Soil Wilting Point for all the different types of soils of the region. For the statistical study, the obtained data series of soil water deficit were adjusted by means of the theoretical Normal Cubic-root probability distribution. An annual threshold value of 200 mm is considered because it is an ecological limit and upper which the drought is the consequence. The intensity of it has been arbitrary classified in: mild, moderate, severe and extreme according the annual values reached. Mann Kendall statistical test was performed and significance trends at levels 0.1, 0.05 and 0.01 were found.Fil: Capriolo, Alberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scarpati, Olga Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Departamento de Geografía; Argentin
The energy-momentum complex in non-local gravity
In General Relativity, the issue of defining the gravitational energy
contained in a given spatial region is still unresolved, except for particular
cases of localized objects where the asymptotic flatness holds for a given
spacetime. In principle, a theory of gravity is not self-consistent, if the
whole energy content is not uniquely defined in a specific volume. Here we
generalize the Einstein gravitational energy-momentum pseudotensor to non-local
theories of gravity where analytic functions of the non-local integral operator
are taken into account. We apply the Noether theorem to a
gravitational Lagrangian, supposed invariant under the one-parameter group of
diffeomorphisms, that is, the infinitesimal rigid translations. The invariance
of non-local gravitational action under global translations leads to a locally
conserved Noether current, and thus, to the definition of a gravitational
energy-momentum pseudotensor, which is an affine object transforming like a
tensor under affine transformations. Furthermore, the energy-momentum complex
remains locally conserved, thanks to the non-local contracted Bianchi
identities. The continuity equations for the gravitational pseudotensor and the
energy-momentum complex, taking into account both gravitational and matter
components, can be derived. Finally, the weak field limit of pseudotensor is
performed to lowest order in metric perturbation in view of astrophysical
applications.Comment: 17 page
Modeling the Distribution of Agricultural Drought by Means of Soil
The extreme hydrologic events in Buenos Aires province (Argentina) had been a constant in its social - economic development. Their impacts mainly over the agriculture have been studied with different scales and point of views. In spite of that, there is a lack of studies of their temporal and spatial distribution in Argentina. Drought is initiated by a reduction in precipitation. The time requires for a lack of rainfall to create a significant deficit in the supplies is variable and could vary from a few weeks to several years. This paper studies the soil water deficit from 1969 to 2008 in the whole Buenos Aires province (307,571 km2) which is divided in 16 sectors according its basins (National Water Resources) and with soil water balance using soil data obtained “in situ”. It was performed using the evapotranspitation formula of Penman - Monteith and considering the soil water constants: Field Capacity, Soil Water Moisture and Soil Wilting Point for all the different types of soils of the region. For the statistical study, the obtained data series of soil water deficit were adjusted by means of the theoretical Normal Cubic-root probability distribution. An annual threshold value of 200 mm is considered because it is an ecological limit and upper which the drought is the consequence. The intensity of it has been arbitrary classified in: mild, moderate, severe and extreme according the annual values reached. Mann Kendall statistical test was performed and significance trends at levels 0.1, 0.05 and 0.01 were found.Facultad de Humanidades y Ciencias de la EducaciónConsejo Nacional de Investigaciones Científicas y Técnica
Considerations on gravitational waves in higher-order local and non-local gravity
The detection of gravitational wave modes and polarizations could constitute
an extremely important signature to discriminate among different theories of
gravity. According to this statement, it is possible to prove that higher-order
non-local gravity has formally the same gravitational spectrum of higher-order
local gravity. In particular, we consider the cases of
gravity, linear with respect to both and and gravity, quadratic with respect
to , where it is demonstrated the graviton amplitude changes if
compared with General Relativity. We also obtain the gravitational spectrum of
higher-order non-local gravity . In this case,
we have three state of polarization and oscillation modes. More in
detail, it is possible to derive two transverse tensor and
standard polarization modes of frequency , massless and with
2-helicity; further scalar modes of frequency
, massive and with 0-helicity, each of which has
the same mixed polarization, partly longitudinal and partly transverse.Comment: 15 pages, to appear in Physics. Lett.
Modeling the Distribution of Agricultural Drought by Means of Soil
The extreme hydrologic events in Buenos Aires province (Argentina) had been a constant in its social - economic development. Their impacts mainly over the agriculture have been studied with different scales and point of views. In spite of that, there is a lack of studies of their temporal and spatial distribution in Argentina. Drought is initiated by a reduction in precipitation. The time requires for a lack of rainfall to create a significant deficit in the supplies is variable and could vary from a few weeks to several years. This paper studies the soil water deficit from 1969 to 2008 in the whole Buenos Aires province (307,571 km2) which is divided in 16 sectors according its basins (National Water Resources) and with soil water balance using soil data obtained “in situ”. It was performed using the evapotranspitation formula of Penman - Monteith and considering the soil water constants: Field Capacity, Soil Water Moisture and Soil Wilting Point for all the different types of soils of the region. For the statistical study, the obtained data series of soil water deficit were adjusted by means of the theoretical Normal Cubic-root probability distribution. An annual threshold value of 200 mm is considered because it is an ecological limit and upper which the drought is the consequence. The intensity of it has been arbitrary classified in: mild, moderate, severe and extreme according the annual values reached. Mann Kendall statistical test was performed and significance trends at levels 0.1, 0.05 and 0.01 were found.Facultad de Humanidades y Ciencias de la EducaciónConsejo Nacional de Investigaciones Científicas y Técnica
Gli affreschi del pittore Vanni Rossi nella cappella della Madonna di Fatima in Milano
Il presente contributo vuole fornire una ricostruzione storica degli affreschi presenti nella cappella della Madonna di Fatima della chiesa dei Santi Nereo e Achilleo di Milano. Partendo dalla edificazione della chiesa e dalla seguente dedicazione della cappella alla Madonna di Fatima, si esamina la ricomposizione delle circostanze che portarono il pittore bergamasco Vanni Rossi a eseguire gli affreschi concernenti i quindici misteri del Rosario e degli avvenimenti intercorsi ai tre pastorelli di Fatima nel 1917. In chiusura di articolo, infine, si ricostruisce il processo che portò il pittore sui ponteggi della cappella; in particolare il contributo vuole soffermarsi sulle figure del cardinale Schuster e di Monsignor Polvara, personaggi importanti per la cultura religiosa milanese durante il Ventennio fascista e nel primo periodo della ricostruzione postbellica, nonché committenti dei lavori per la decorazione della Cappella
Lo pseudotensore energia-impulso in teorie estese della gravitazione
2016 - 2017The gravitational field’s energy and momentum definitions are treated in
extensive gravitation theories, through the generalization of the energymomentum
pseudotensor, defined by Einstein in general relativity. This extension
was obtained by modifying the Lagrangian of Hilbert-Einstein or by
using a different connection from the one of Levi- Civita as that of Weitzenböck
for teleparallel theories. We have firstly obtained the gravitational
energy-momentum pseudotensor for extended Lagrangians that depend on
the metric gμ⌫ and on its derivatives up to nth order and then demonstrated,
in general, its affine and non-covariant behavior. Then we applied the weak
field limit to Euler-Lagrange equations associated to the Lagrangian which
depends linearly on the ⇤R terms and derived the modified gravitational
waves with six polarization states, three transverse and three not, with helicity
0 and 2. Subsequently we have obtained, through the Noether theorem for
infinitesimal rigid translations, the relative energy-momentum pseudotensor
and after having developed it to the order h2 and mediated on an suitable
domain, we have calculated the power emitted from a possible gravitational
radiant source. For gravity f (R) and f (T) we have obtained the respective
energy-momentum pseudotensors and, via the border therm B which
connects the curvature R to the torsion T, we have studied the relative pseudotensor
⌧↵
#|!(T,B) allowing us to link ⌧↵
#|f(R) and ⌧↵
#|f(T). Finallywehave obtained
the equations for two theories of higher order telepallel gravity: in particular
for the Lagrangian L⇤kT = h
!
T +
Pp
k=0 akT⇤kT
#
and for the sixth
order telepallel gravity equivalent to LR⇤R = p−g (−R + a0R2 + a1R⇤R). [edited by author]XXX n.s
Pratiche redazionali nel Regno di Napoli in età aragonese: realtà territoriali a confronto
The legislative provisions on notaries issued by the Aragonese sovereigns intended to align the editorial procedures and the admission to the notary profession in the Reign of Sicily citra and ultra Farum, together with the procedures of registration and conservation of notarial documents. However, these procedures were not always equally adopted in all the districts of the Reign. On this regard, the following article presents some samples of notarial registers produced in the Province of Principato Citra, that testify to some unique notarial procedures also comparable with other contemporary evidence from Italy and from the Mediterranean Basin
Gli affreschi del pittore Vanni Rossi nella cappella della Madonna di Fatima in Milano
Il presente contributo vuole fornire una ricostruzione storica degli affreschi presenti nella cappella della Madonna di Fatima della chiesa dei Santi Nereo e Achilleo di Milano. Partendo dalla edificazione della chiesa e dalla seguente dedicazione della cappella alla Madonna di Fatima, si esamina la ricomposizione delle circostanze che portarono il pittore bergamasco Vanni Rossi a eseguire gli affreschi concernenti i quindici misteri del Rosario e degli avvenimenti intercorsi ai tre pastorelli di Fatima nel 1917. In chiusura di articolo, infine, si ricostruisce il processo che portò il pittore sui ponteggi della cappella; in particolare il contributo vuole soffermarsi sulle figure del cardinale Schuster e di Monsignor Polvara, personaggi importanti per la cultura religiosa milanese durante il Ventennio fascista e nel primo periodo della ricostruzione postbellica, nonché committenti dei lavori per la decorazione della Cappella
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