4,735 research outputs found
Influência da morfologia do terreno nas características do solo em terrenos agrícolas do Alentejo – aplicação de classificações geomorfométricas.
Neste artigo utiliza-se um Modelo de
Elevação Digital (MED) para elaborar e
comparar diferentes classificações da
morfologia do terreno quanto ao seu
potencial para a diferenciação da espessura e da textura do solo. As classificações
baseiam-se em observações de campo
(UTobs e PEobs-L) ou no cálculo de
variáveis geomorfométricas num MED
(UTx, UTx-L e PEx-L). Aplicam-se a
uma área localizada a 80 km a Este de
Évora, próximo de Terena, Alandroal,
numa parcela cultivada com milho regado
por rampa rotativa desde 1994 e com uma
morfologia ondulada em que os declives
variam entre 1% e 28%. Fez-se o levantamento topográfico baseado num sistema
de posicionamento global, a elaboração de
um MED e o cálculo de vários parâmetros
geomorfométricos de âmbito local e
regional. A amostragem do solo incidiu
em dois blocos (A e B), segundo uma
malha relativamente regular, recorrendo a
uma sonda mecânica cilíndrica com 87
mm de diâmetro e 120 cm de profundidade. Os resultados da espessura do solo e
da textura da camada 0-20 cm de 203
sondagens são usados para avaliar a
homogeneidade e a diferenciação das unidades de terreno (UT) obtidas com as
classificações morfológicas. Todas as
classificações testadas se revelaram pouco
eficientes a diferenciar os solos quanto à
granulometria. Os resultados foram
melhores na diferenciação das variáveis
de espessura, em especial a profundidade
máxima observada (PMX) e a profundidade até à camada R (PR), apresentandose as classificações pela seguinte sequência qualitativa: UTobs-L > PEobs-L >
PEx-L. As classificações por observação
de campo obtiveram melhores resultados,
mas as classificações geomorfométricas
baseadas em variáveis regionais (PEx-L)
foram melhores que as baseadas em
variáveis locais (UTx e UTx-L). No caso
da espessura, a eliminação de
UT < 100 m
2 melhorou sempre a resposta
das classificações
Delineation of management zones using mobile measurements of soil apparent electrical conductivity and multivariate geostatistical techniques
Site-specific management promotes the identification and management of areas within the field, which represent subfield regions with homogeneous characteristics (management zones). However,
determination of subfield areas is difficult because of the complex combination of factors which could affect crop yield. One possibility to capture yield variability is the use of soil physical properties to define
the management zones as they are related to plant available water.
With the aim of characterizing the spatial variability of the main soil physical variables and using this information to determine potential management zones, soil samples were taken from 70 locations in a
33-ha field in Badajoz, southwestern Spain. Firstly, accurate spatial distribution maps of the soil attributes were generated by using regression kriging as the most suitable algorithm in which exhaustive secondary information on soil apparent electrical conductivity (ECa) was incorporated. ECa
measurements were carried out with a Veris 3100 operating in both shallow (0–30 cm), ECs, and deep (0–90 cm), ECd,mode. Clay, coarse sand and fine sand were the soil physical properties which exhibited
higher correlation with ECa (positively correlated with the finer texture component, clay, and negatively correlated with the coarser ones, coarse and fine sands), particularly with ECs. Thus, this was the
secondary variable used to obtain the kriged maps. Later, principal component analysis and fuzzy cluster
classification were performed to delineate management zones, resulting in two subfields to be managed separately. This number of subfields was determined using the fuzzy performance index and normalized
classification entropy as the way to optimize the classification algorithm
Reinfection with SARS-CoV-2: An inconvenient truth?
Data show that antibody-related immunity against SARS-CoV-2 may not be long-lasting. We report two cases regarded as cured from COVID-19, which presented again with symptoms and a positive SARS-CoV-2 RT-PCR test. Case one, a 60-year-old male, had a biphasic presentation of symptoms compatible with COVID-19 infection, associated with a positive RT-PCR test. Case two, a 25-year-old female, had a first positive RT-PCR test during hospital screening, and months later a symptomatic presentation of COVID-19, associated with a positive RT-PCR test. All cases were immunocompetent. Anti-IgG-SARS-CoV-2 blood samples were negative in both. Elevation of analytical inflammatory markers suggested new infection in both cases. COVID-19 reinfection may be a differential diagnosis and primary care physicians should acknowledge it. Previously cured patients should be encouraged to comply with health public preventive measures
Yield potential probability maps using the Rasch model
Yield monitors commonly show that there are very large yield differences within a field
which often differ from year to year. Because our ability to estimate reductions in growth
and to quantify yield losses resulting from complex interactions and multiple stresses is
limited, it does not appear feasible to analyse yield variability using a point to point
strategy. For a farmer it is important to select parcels of land, or parts of a parcel, with
a high yield probability. To analyse the high yield probability zones the Rasch model is used
considering a multi-temporal yield data set. The Rasch measure for multi-temporal yield
data makes it possible to place on a continuum axis the yield samples considered in terms
of annual yield and vice versa. Using the Rasch measurement one can produce yield
potential probabilistic maps taking into account each sample coordinate. From a quantitative
point of view it is possible to find yield samples that do not support the model, or
which do not reach the expected levels. Positive and negative mismatches can be analysed
individually or according to a particular year yield. Thus, the Rasch model makes it possible
to systematise the data, making it an effective tool for making appropriate decisions
regarding areas with higher yield performance and greater stability over time. Also, it
makes it possible to compare the yields of different samples and provide appropriate
measures to correct, differentially, samples that obtained different inadequate levels
Soil apparent electrical conductivity and geographically weighted regression for mapping soil
To resolve the spatial variation in soil properties intensively is expensive, but
such knowledge is essential to manage the soil better and to achieve greater economic and
environmental benefits. The objective of this study was to determine whether the soil
apparent electrical conductivity (ECa), alone or combined with other variables, is a useful
alternative for providing detailed information on the soil in the Extremadura region of
Spain. Apparent soil electrical conductivity was measured and geographically weighted
regression was used to characterize the spatial variation in soil properties, which in turn
can be used for soil management. This study shows that soil cation exchange capacity,
calcium content, clay percentage and pH have a relatively strong spatial correlation with
ECa in the soil of the study area
Euclid: Superluminous supernovae in the Deep Survey
Context. In the last decade, astronomers have found a new type of supernova called superluminous supernovae (SLSNe) due to their high peak luminosity and long light-curves. These hydrogen-free explosions (SLSNe-I) can be seen to z ~ 4 and therefore, offer the possibility of probing the distant Universe.
Aims. We aim to investigate the possibility of detecting SLSNe-I using ESA’s Euclid satellite, scheduled for launch in 2020. In particular, we study the Euclid Deep Survey (EDS) which will provide a unique combination of area, depth and cadence over the mission.
Methods. We estimated the redshift distribution of Euclid SLSNe-I using the latest information on their rates and spectral energy distribution, as well as known Euclid instrument and survey parameters, including the cadence and depth of the EDS. To estimate the uncertainties, we calculated their distribution with two different set-ups, namely optimistic and pessimistic, adopting different star formation densities and rates. We also applied a standardization method to the peak magnitudes to create a simulated Hubble diagram to explore possible cosmological constraints.
Results. We show that Euclid should detect approximately 140 high-quality SLSNe-I to z ~ 3.5 over the first five years of the mission (with an additional 70 if we lower our photometric classification criteria). This sample could revolutionize the study of SLSNe-I at z > 1 and open up their use as probes of star-formation rates, galaxy populations, the interstellar and intergalactic medium. In addition, a sample of such SLSNe-I could improve constraints on a time-dependent dark energy equation-of-state, namely w(a), when combined with local SLSNe-I and the expected SN Ia sample from the Dark Energy Survey.
Conclusions. We show that Euclid will observe hundreds of SLSNe-I for free. These luminous transients will be in the Euclid data-stream and we should prepare now to identify them as they offer a new probe of the high-redshift Universe for both astrophysics and cosmology.Acknowledgements. We thank the internal EC referees (P. Nugent and J.
Brichmann) as well as the many comments from our EC colleagues and friends.
C.I. thanks Chris Frohmaier and Szymon Prajs for useful discussions about
supernova rates. C.I. and R.C.N. thank Mark Cropper for helpful information
about the V IS instrument. C.I. thanks the organisers and participants of the
Munich Institute for Astro- and Particle Physics (MIAPP) workshop “Superluminous supernovae in the next decade” for stimulating discussions and the
provided online material. The Euclid Consortium acknowledges the European
Space Agency and the support of a number of agencies and institutes that
have supported the development of Euclid. A detailed complete list is available on the Euclid web site (http://www.euclid-ec.org). In particular the
Agenzia Spaziale Italiana, the Centre National dEtudes Spatiales, the Deutsches
Zentrum für Luft- and Raumfahrt, the Danish Space Research Institute, the Fundação para a Ciênca e a Tecnologia, the Ministerio de Economia y Competitividad, the National Aeronautics and Space Administration, The Netherlandse
Onderzoekschool Voor Astronomie, the Norvegian Space Center, the Romanian
Space Agency, the State Secretariat for Education, Research and Innovation
(SERI) at the Swiss Space Office (SSO), the United Kingdom Space Agency,
and the University of Helsinki. R.C.N. acknowledges partial support from the
UK Space Agency. D.S. acknowledges the Faculty of Technology of the University of Portsmouth for support during his PhD studies. C.I. and S.J.S. acknowledge funding from the European Research Council under the European
Union’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement No. [291222]. C.I. and M.S. acknowledge support from EU/FP7-ERC
grant No. [615929]. E.C. acknowledge financial contribution from the agreement ASI/INAF/I/023/12/0. The work by KJ and others at MPIA on NISP was
supported by the Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) under
grant 50QE1202. M.B. and S.C. acknowledge financial contribution from the
agreement ASI/INAF I/023/12/1. R.T. acknowledges funding from the Spanish
Ministerio de Economía y Competitividad under the grant ESP2015-69020-C2-
2-R. I.T. acknowledges support from Fundação para a Ciência e a Tecnologia
(FCT) through the research grant UID/FIS/04434/2013 and IF/01518/2014. J.R.
was supported by JPL, which is run under a contract for NASA by Caltech and
by NASA ROSES grant 12-EUCLID12-0004
Redução de compostos fenólicos de resíduos de lagares de azeite utilizando culturas de Coriolus versicolor
In this study, C. versicolor cultures were performed during 20 days with different RLA (olive mill wastes)subtracts, 50%, 75% and 100%. During this assay, samples were collected in regular time intervals, cell growth were evaluated and broth decolorization was observed. The organic matter and total phenolic compounds level in
the culture broth showed a decrease in all RLA ratios. 50% and 75% RLA presented high total phenolic removal, 85% and 90% respectively. In the end of the assay, toxicological evaluation of the culture broth was performed against Artemia salina. These results showed a toxicological decrease of these residues after biological treatment
with C. Versicolor
Evaluation of spatial and temporal variability of pasture based on topography and the quality of the rainy season
Yield and botanical composition of a given dry-land pasture are heavily influenced by rainfall distribution, and vary according to topography. Through analyzing these parameters, it is possible to identify patterns of spatial distribution, related to
topographic characteristics, which can be used to improve spatial management of pasture.
The main objective of this project was to assess the role of rainfall, temperature and
topography in the spatial and temporal variability of pasture and establish models for predicting the spatial distribution and yield of certain plant species, based on its topographic characteristics. This study was carried out over three years, 2004 to 2006, in a dryland
pasture located in Southern Portugal. The data obtained were analyzed as a function of
distance to flow lines and the results demonstrate that certain topographical characteristics,
associated with agronomic information, can be very useful in explaining the spatial and
temporal variability of yield and the botanical composition of the pasture. The slope of the linear regression of the variables mentioned can be used to estimate the spatial variation of
yield and the botanical composition as a function of distance to flow lines. The regression coefficient can be estimated from the annual rainfall, given the strong correlation between the two
Towards Lightweight Data Integration using Multi-workflow Provenance and Data Observability
Modern large-scale scientific discovery requires multidisciplinary
collaboration across diverse computing facilities, including High Performance
Computing (HPC) machines and the Edge-to-Cloud continuum. Integrated data
analysis plays a crucial role in scientific discovery, especially in the
current AI era, by enabling Responsible AI development, FAIR, Reproducibility,
and User Steering. However, the heterogeneous nature of science poses
challenges such as dealing with multiple supporting tools, cross-facility
environments, and efficient HPC execution. Building on data observability,
adapter system design, and provenance, we propose MIDA: an approach for
lightweight runtime Multi-workflow Integrated Data Analysis. MIDA defines data
observability strategies and adaptability methods for various parallel systems
and machine learning tools. With observability, it intercepts the dataflows in
the background without requiring instrumentation while integrating domain,
provenance, and telemetry data at runtime into a unified database ready for
user steering queries. We conduct experiments showing end-to-end multi-workflow
analysis integrating data from Dask and MLFlow in a real distributed deep
learning use case for materials science that runs on multiple environments with
up to 276 GPUs in parallel. We show near-zero overhead running up to 100,000
tasks on 1,680 CPU cores on the Summit supercomputer.Comment: 10 pages, 5 figures, 2 Listings, 42 references, Paper accepted at
IEEE eScience'2
The Analyticity of a Generalized Ruelle's Operator
In this work we propose a generalization of the concept of Ruelle operator
for one dimensional lattices used in thermodynamic formalism and ergodic
optimization, which we call generalized Ruelle operator, that generalizes both
the Ruelle operator proposed in [BCLMS] and the Perron Frobenius operator
defined in [Bowen]. We suppose the alphabet is given by a compact metric space,
and consider a general a-priori measure to define the operator. We also
consider the case where the set of symbols that can follow a given symbol of
the alphabet depends on such symbol, which is an extension of the original
concept of transition matrices from the theory of subshifts of finite type. We
prove the analyticity of the Ruelle operator and present some examples
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