702 research outputs found
Coping with salinity in irrigated agriculture: crop evapotranspiration and water management issues
ReviewSoil and water salinity and associated problems are a major challenge for global food production. Strategies to
cope with salinity include a better understanding of the impacts of temporal and spatial dynamics of salinity on
soil water balances vis-Ă -vis evapotranspiration (ET) and devising optimal irrigation schedules and efficient
methods. Both steady state and transient models are now available for predicting salinity effects on reduction of
crop growth and means for its optimization. This paper presents a brief review on the different approaches
available, focusing on the FAO56 framework for coping with the effects of soil salinity on crop ET and yields. The
FAO56 approach, applied widely in soil water balance models, is commonly used to compute water requirements,
including leaching needs. It adopts a daily stress coefficient (Ks) representing both water and salt stresses
to adjust the crop coefficient (Kc) when it is multiplied by the grass reference ETo to obtain the actual crop ET
values for saline environments (ETc act=Ks Kc ETo). The same concept is also applied to the dual Kc approach,
with Ks used to adjust the basal crop coefficient (Kcb). A review on applications of Ks is presented showing that
the FAO56 approach may play an interesting role in water balance computations aimed at supporting irrigation
scheduling. Transient state models, through alternative formulations, provide additional solutions for quantification
of the salinity build-up in the root zone. These include irrigation-induced salinity, upward movement of
salts from saline ground water-table, and sodification processes. Regardless of the approach, these models are
now very much capable of supporting irrigation water management in saline stress conditions. For maintaining
crop growth under salinity environments, soil-crop-water management interventions consistent with site-specific
conditions are then discussed. Adequateness of irrigation methods, cyclic uses of multi-salinity waters and
proper irrigation scheduling are further analyzed as examples of efficient means to obviate the effects of salinityinfo:eu-repo/semantics/publishedVersio
Antitumor drugs reval that eukaryotic elongation factors EeflBÎł and eEF1Bd are phosphorylated durging mitosis
Comunicaciones a congreso
First exposure to Arduino through peer-coaching: Impact on students' attitudes towards programming
In this paper we report the work that jeKnowledge (JĂșnior Empresa da Faculdade de CiĂȘncias e Tecnologias da Universidade de Coimbra), a student-led initiative, has done in the âjeKnowledge academyâ courses to actively engage Portuguese high-school students in STEM education through hands-on projects based on the low-cost Arduino platform. F2F activities, based on a peer-assisted learning strategy, were complemented with tutorials and more advanced project suggestions in a blog. Pre and post surveys on students'' attitudes towards programming and peer-coaching were administered to pre-university and first year college participants, finding an overall increase in the Likert scale for all the programming-related constructs under study (confidence, interest, gender, usefulness and professional) after the introductory course. As regards the peer-based learning approach, younger students seemed to be more eager to be taught in a less formal way than their older counterparts. The course resulted in high degrees of satisfaction for both the student tutors and their tutees
An erbium(III)-based NIR emitter with a highly conjugated Ă-diketonate for blue-region sensitization
The sensitization of lanthanide complexes in the visible region is of particular interest for practical applications such as labeling, biological analysis and optoelectronics. A visible-light sensitized Er3+complex based on the use of a highly conjugated Ă-diketonate (1, 3-di(2-naphthyl)-1, 3-propanedione, Hdnm) and 5-nitro-1, 10-phenanthroline (5NO2phen) as an ancillary ligand, [Er(dnm)3(5NO2phen)], has been synthesized, fully characterized and its photophysical properties have been investigated. Suitably expanded p-conjugation in the complex molecule makes the excitation window red-shifted to the visible region (up to 550 nm). Efficient energy transfer by antenna effect results in 1.53 ”m emission from the Er3+ion
The antitumor drug vinblastine induces the phosphorylation of annexin A2
Comunicaciones a congreso
Do AGN triggering mechanisms vary with radio power? â I. Optical morphologies of radio-intermediate HERGs
Active galactic nuclei (AGNs) with intermediate radio powers are capable of driving multiphase outflows in galaxy bulges, and are also more common than their high-radio-power counterparts. In-depth characterization of the typical host galaxies and likely triggering mechanisms for this population is therefore required in order to better understand the role of radio AGN feedback in galaxy evolution. Here, we use deep optical imaging data to study the detailed host morphologies of a complete sample of 30 local radio AGNs with high-excitation optical emission (HERG) spectra and intermediate radio powers [ z 25.0âWâHz-1] with strong optical emission lines: 53 ± 9 per cent compared with 94 ± 4 per cent. In addition, the most radio-powerful half of the sample has a higher frequency of morphological disturbance than the least radio-powerful half (67 ± 12 per cent and 40 ± 13 per cent, respectively), including the eight most highly disturbed galaxies. This suggests that the importance of triggering nuclear activity in high-excitation radio galaxies (HERGs) through mergers and interactions reduces with radio power. Both visual inspection and detailed light profile modelling reveal a mixed population of early-type and late-type morphologies, contrary to the massive elliptical galaxy hosts of radio-powerful AGNs. The prevalence of late-type hosts could suggest that triggering via secular, disc-based processes has increased importance for HERGs with lower radio powers (e.g. disc instabilities and large-scale bars)
Investigating the impact of quasar-driven outflows on galaxies at z ⌠0.3â0.4
Aims. We present a detailed study of the kinematics of 19 type 2 quasars (QSO2s) with redshifts in the range 0.3ââ108.5âLâ. We aim to advance our understanding of the active galactic nucleus (AGN) feedback phenomenon by correlating outflow properties with (i) young stellar populations (YSPs) with ages < 100 Myr, (ii) the optical morphology and the environment of the galaxies, and (iii) the radio luminosity.
Methods. We characterized the ionized gas kinematics using the [OIII]λ5007 Ă
emission line profiles detected in intermediate spectral resolution (RââŒâ1500â2500) optical spectra of the QSO2s. To do this, we employed three different outflow detection methods: multicomponent parametric, flux-weighted nonparametric, and peak-weighted nonparametric.
Results. We detect ionized outflows in 18 of the 19 QSO2s using the parametric analysis, and in all of them using the nonparametric methods. We find higher outflow masses using the parametric analysis (average log MOF(Mâ) = 6.47ââ
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â0.50), and higher mass rates and kinetic powers with the flux-weighted nonparametric method (MOFâ=â4.0ââ
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â4.4âMâ yrâ1 and Ekinâ=â41.9ââ
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â0.6 erg sâ1). However, when we use the parametric method and the maximum outflow velocities (vmax), we measure the highest outflow mass rates and kinetic energies (MOFâ=â23ââ
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â35âMâ yrâ1 and log(Ekin) = 42.9ââ
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â0.6 erg sâ1). We do not find any significant correlation between the outflow properties and the previously mentioned AGN and galaxy-wide properties.
Conclusions. Four of the five QSO2s without a YSP of age < 100 Myr show highly disturbed kinematics, whereas only 5 out of the 14 QSO2s with YSPs show similarly asymmetric [OIII] profiles. Despite the small sample size, this might be indicative of negative feedback. The lack of a correlation between the outflow properties and the galaxies optical morphologies might be due to their different dynamical timescales (millions of years in the case of the outflows versus billions of years in the case of galaxy mergers). Last, the small radio luminosity range covered by our sample, log(L5âGHz) = [22.1, 24.7] W Hzâ1, may impede the detection of any correlation between radio emission and outflow properties
In support of the ICCAT ecosystem report card: advances in monitoring the impacts on and the state of the âfoodweb and trophic relationshipsâ ecosystem component.
In support of the development of the ICCAT Ecosystem Report Card, this paper addresses the âfoodweb/trophic relationshipsâ ecosystem component. Specifically, it contributes towards developing the following elements: (1) we describe what this component means in the context of ICCAT species and fisheries and the importance of monitoring it; (2) we describe the role of ecological indicators and ecosystem models in monitoring this ecosystem component; (3) we present a list of candidate ecological indicators that could be estimated to monitor this component; (4) we discuss the main challenges in monitoring this ecosystem component and indicator development; and finally (5), we draft a work plan to guide our future work. We invite the ICCAT community and others to contribute towards the development of ecological indicators and ecosystem models to monitor this ecosystem component. If interested, contact the corresponding authors to find out how you can contribute to this initiative.VersiĂłn del editor
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