307 research outputs found
Increasing farmers’ skills towards a sustainable agriculture
De modo a praticar uma agricultura sustentável, os agricultores devem adotar práticas corretas e respeitadoras do ambiente, utilizando a tecnologia adequada e cumprindo a regulamentação da UE para uma agricultura sustentável. Os desenvolvimentos recentes da ciência e da tecnologia, que poderiam ser um valor acrescentado para a gestão das culturas e da terra, continuam a não ser utilizados em muitas situações por não terem chegado ao conhecimento dos agricultores ou estes não terem sido treinados para os utilizar. O objectivo deste estudo foi o de definir competências no domínio da tecnologia agrícola, em áreas onde ocorreram avanços tecnológicos que podem ajudar os agricultores a praticar uma agricultura mais sustentável. Foram identificadas seis áreas principais: 1) Agricultura de precisão; 2) Proteção integrada; 3) Reutilização agrícola de resíduos orgânicos; 4) Rega gota-a-gota e tecnologias de conservação da água; 5) Energias renováveis e 6) Bioenergia e culturas energéticas. Para cada uma destas áreas foram definidas competências específicas com enfâse na sensibilização sobre os aspectos da sustentabilidade na agricultura e na introdução aos principais desenvolvimentos tecnológicos. Estas competências foram depois utilizadas no desenvolvimento de um novo programa de formação profissional para agricultores, cujos cursos de formação decorreram durante o ano de 2019 na Grécia, Itália e Portugal, para um total de cerca de 600 agricultores
A Theory of a Spot
We present a simple inflationary scenario that can produce arbitrarily large
spherical underdense or overdense regions embedded in a standard Lambda cold
dark matter paradigm, which we refer to as bubbles. We analyze the effect such
bubbles would have on the Cosmic Microwave Background (CMB). For super-horizon
sized bubble in the vicinity of the last scattering surface, a signal is
imprinted onto CMB via a combination of Sach-Wolfe and an early integrated
Sach-Wolfe (ISW) effects. Smaller, sub-horizon sized bubbles at lower redshifts
(during matter domination and later) can imprint secondary anisotropies on the
CMB via Rees-Sciama, late-time ISW and Ostriker-Vishniac effects. Our scenario,
and arguably most similar inflationary models, produce bubbles which are
over/underdense in potential: in density such bubbles are characterized by
having a distinct wall with the interior staying at the cosmic mean density. We
show that such models can potentially, with only moderate fine tuning, explain
the \emph{cold spot}, a non-Gaussian feature identified in the Wilkinson
Microwave Anisotropy Probe (WMAP) data by several authors. However, more
detailed comparisons with current and future CMB data are necessary to confirm
(or rule out) this scenario.Comment: 19 pages, 19 figures, added references and explanations, JCAP in
pres
Training and Learning Needs for MSc Programs in Sustainable Agriculture
Sustainable agriculture is urgently needed to promote conservation and sustainable resources use in an equitable manner through integrated management of land, water, energy and biodiversity. In this way, education in agriculture emerges as a crucial tool for preparing agricultural technicians, researchers and farmers for productive contributions. Higher education institutions arise with an important mission of education in the context of social transformation and to integrate sustainable development into the educational system as a scientific subject. The aim of this study was to identify the training and learning needs to be included in a MSc program in sustainable agriculture. It was based on a questionnaire prepared and distributed to academics’ experts in Agrarian Sciences in Greece, Italy and Portugal.
Technologies, legislation, management and business, local community leadership and marketing were the training needs considered very important expertise’s in sustainable agriculture. Traditional face-to-face learning, experienced farmers as mentors and knowledge sharing mechanisms were rated as very applicable and important. Due to COVID-19 pandemic, online learning methods, which were not considered suitable for a MSc program in sustainable agriculture,
became important by providing online education. Information and communication technology and technological tools showed to be important skills for sustainable agricultural practices to effectively implement online learning and to improve the efficient access, exposure and use of up-to-date information of the agricultural sector and awareness of sustainable agricultural practices
SCI1 Is a Direct Target of AGAMOUS and WUSCHEL and Is Specifically Expressed in the Floral Meristematic Cells
The specified floral meristem will develop a pre-established number of floral organs and, thus, terminate the floral meristematic cells. The floral meristematic pool of cells is controlled, among some others, by WUSCHEL (WUS) and AGAMOUS (AG) transcription factors (TFs). Here, we demonstrate that the SCI1 (Stigma/style cell-cycle inhibitor 1) gene, a cell proliferation regulator, starts to be expressed since the floral meristem specification of Nicotiana tabacum and is expressed in all floral meristematic cells. Its expression is higher in the floral meristem and the organs being specified, and then it decreases from outside to inside whorls when the organs are differentiating. SCI1 is co-expressed with N. tabacum WUSCHEL (NtWUS) in the floral meristem and the whorl primordia at very early developmental stages. Later in development, SCI1 is co-expressed with NAG1 (N. tabacum AG) in the floral meristem and specialized tissues of the pistil. In silico analyses identified cis-regulatory elements for these TFs in the SCI1 genomic sequence. Yeast one-hybrid and electrophoresis mobility shift assay demonstrated that both TFs interact with the SCI1 promoter sequence. Additionally, the luciferase activity assay showed that NAG1 clearly activates SCI1 expression, while NtWUS could not do so. Taken together, our results suggest that during floral development, the spatiotemporal regulation of SCI1 by NtWUS and NAG1 may result in the maintenance or termination of proliferative cells in the floral meristem, respectively
Elemental Chemometrics as Tools to Depict Stalked Barnacle (Pollicipes pollicipes) Harvest Locations and Food Safety
The stalked barnacle Pollicipes pollicipes is an abundant species on the very exposed rocky shore habitats of the Spanish and Portuguese coasts, constituting also an important economical resource, as a seafood item with high commercial value. Twenty-four elements were measured by untargeted total reflection X-ray fluorescence spectroscopy (TXRF) in the edible peduncle of stalked barnacles sampled in six sites along the Portuguese western coast, comprising a total of 90 individuals. The elemental profile of 90 individuals originated from several geographical sites (N = 15 per site), were analysed using several chemometric multivariate approaches (variable in importance partial least square discriminant analysis (VIP-PLS-DA), stepwise linear discriminant analysis (S-LDA), linear discriminant analysis (LDA), random forests (RF) and canonical analysis of principal components (CAP)), to evaluate the ability of each approach to trace the geographical origin of the animals collected. As a suspension feeder, this species introduces a high degree of background noise, leading to a comparatively lower classification of the chemometric approaches based on the complete elemental profile of the peduncle (canonical analysis of principal components and linear discriminant analysis). The application of variable selection approaches such as the VIP-PLS-DA and S-LDA significantly increased the classification accuracy (77.8% and 84.4%, respectively) of the samples according to their harvesting area, while reducing the number of elements needed for this classification, and thus the background noise. Moreover, the selected elements are similar to those selected by other random and non-random approaches, reinforcing the reliability of this selection. This untargeted analytical procedure also allowed to depict the degree of risk, in terms of human consumption of these animals, highlighting the geographical areas where these delicacies presented lower values for critical elements compared to the standard thresholds for human consumption
Flavor changing single top quark production channels at e^+e^- colliders in the effective Lagrangian description
We perform a global analysis of the sensitivity of LEP2 and e^+e^- colliders
with a c.m. energy in the range 500 - 2000 GeV to new flavor-changing single
top quark production in the effective Lagrangian approach. The processes
considered are sensitive to new flavor-changing effective vertices such as Ztc,
htc, four-Fermi tcee contact terms as well as a right-handed Wtb coupling. We
show that e^+ e^- colliders are most sensitive to the physics responsible for
the contact tcee vertices. For example, it is found that the recent data from
the 189 GeV LEP2 run can be used to rule out any new flavor physics that can
generate these four-Fermi operators up to energy scales of \Lambda > 0.7 - 1.4
TeV, depending on the type of the four-Fermi interaction. We also show that a
corresponding limit of \Lambda > 1.3 - 2.5 and \Lambda > 17 - 27 TeV can be
reached at the future 200 GeV LEP2 run and a 1000 GeV e^+e^- collider,
respectively. We note that these limits are much stronger than the typical
limits which can be placed on flavor diagonal four-Fermi couplings. Similar
results hold for \mu^+\mu^- colliders and for tu(bar) associated production.
Finally we briefly comment on the necessity of measuring all flavor-changing
effective vertices as they can be produced by different types of heavy physics.Comment: 34 pages, plain latex, 7 figures embadded in the text using epsfig.
Added new references and discussions regarding their relevance to the paper.
Added more comments on the comparison between flavor-changing and
flavor-diagonal contact terms and on the importance of measuring the Ztc
verte
Conformal Transformations in Cosmology of Modified Gravity: the Covariant Approach Perspective
The 1+3 covariant approach and the covariant gauge-invariant approach to
perturbations are used to analyze in depth conformal transformations in
cosmology. Such techniques allow us to obtain very interesting insights on the
physical content of these transformations, when applied to non-standard
gravity. The results obtained lead to a number of general conclusions on the
change of some key quantities describing any two conformally related
cosmological models. In particular, it is shown that the physics in the
Einstein frame has characteristics which are completely different from those in
the Jordan frame. Even if some of the geometrical properties of the cosmology
are preserved (homogeneous and isotropic Universes are mapped into homogeneous
and isotropic universes), it can happen that decelerating cosmologies are
mapped into accelerated ones. Differences become even more pronounced when
first-order perturbations are considered: from the 1+3 equations it is seen
that first-order vector and tensor perturbations are left unchanged in their
structure by the conformal transformation, but this cannot be said of the
scalar perturbations, which include the matter density fluctuations. Behavior
in the two frames of the growth rate, as well as other evolutionary features,
like the presence or absence of oscillations, etc., appear to be different too.
The results obtained are then explicitly interpreted and verified with the help
of some clarifying examples based on -gravity cosmologies.Comment: 26 pages, 8 figure
BEC Collapse and Dynamical Squeezing of Vacuum Fluctuations
We analyze the phenomena of Bose Novae, as described by Donley et al [Nature
412, 295 (2001)], by focusing on the behavior of excitations or fluctuations
above the condensate, as driven by the dynamics of the condensate (rather than
the dynamics of the condensate alone or the kinetics of the atoms). The
dynamics of the condensate squeezes and amplifies the quantum excitations,
mixing the positive and negative frequency components of their wave functions
thereby creating particles which appear as bursts and jets. By analyzing the
changing amplitude and particle content of these excitations, our simple
physical picture (based on a test field approximation) explains well the
overall features of the Bose Novae phenomena and provide excellent quantitative
fits with experimental data on several aspects, such as the scaling behavior of
the collapse time and the amount of particles in the jet. The predictions of
the bursts at this level of approximation is less than satisfactory but may be
improved on by including the backreaction of the excitations on the condensate.
The mechanism behind the dominant effect -- parametric amplification of vacuum
fluctuations and freezing of modes outside of horizon -- is similar to that of
cosmological particle creation and structure formation in a rapid quench (which
is fundamentally different from Hawking radiation in black holes). This shows
that BEC dynamics is a promising venue for doing `laboratory cosmology'.Comment: Latex 36 pages, 6 figure
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS
The chi_b(nP) quarkonium states are produced in proton-proton collisions at
the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS
detector. Using a data sample corresponding to an integrated luminosity of 4.4
fb^-1, these states are reconstructed through their radiative decays to
Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks
corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new
structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is
also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes.
This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table,
corrected author list, matches final version in Physical Review Letter
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