Introduction. The production potential of grain amaranth has recently been demonstrated in northeastern Patagonia, Argentina. This crop under irrigation and in a temperate semi-arid climate showed an ...adequate development of the plants in their different phenological stages with high economic performance. Objectives. This study explored the response of Amaranthus cruentus cv Mexicano to different irrigation frequencies in the lower valley of Río Negro river, Patagonia, Argentina. Method. The experimental design was of three blocks with randomized treatments (subplots), each one corresponding to a different irrigation frequency. The first six irrigations were performed every 7 days for all the treatments, to ensure the establishment of the crop. Then the following treatments were applied: irrigation every 7 days (FI), every 14 days (FII), and every 21 days (FIII). The following biometric variables and their components were measured: height of plant, number of leaves, biomass and economic yield. Results. The results suggest that the optimum irrigation frequency was FII (14 days), resulting in an adequate plant stand at panicle initiation and allows a proper development of plant with optimal biological and economical yields and the highest efficiency of water use (4.02 kg·m-3). Conclusions. The contributions of this study demonstrated the production potential of A. cruentus crop in the lower valley of the Río Negro river under irrigation, representing the southernmost study on irrigation frequency made for this grain crop in the world. A management of irrigation water of 7 days for the establishment of the crop and then with a frequency of 14 days showed the highest yield and the best water use efficiency.
Fréquence d'irrigation de l'amarante dans le nord-est de la Patagonie, Argentine Introduction. Récemment, il a été démontré le potentiel de la culture d’amarante en Patagonie du Nord, en Argentine. Cette culture sous irrigation et en climat tempéré semi-aride a montré un développement adéquat des plantes dans leurs différents stades phénologiques avec des performances économiques élevées Objectifs. Cette étude a exploré la réponse de Amaranthus cruentus cv Mexicano à une fréquence différente d’irrigation dans la basse vallée de la rivière Río Negro, en Patagonie, en Argentine. Méthode. Un modèle expérimental de trois blocs avec des traitements randomisés (sous-parcelles), chacun correspondant à différentes fréquences d'irrigation, a été appliqué. Les six premières irrigations pour tous les traitements effectués tous les 7 jours eurent pour but d'assurer l'implantation de la culture. Ensuite, la FI a maintenu cette fréquence, la FII tous les 14 jours et FIII tous les 21 jours. Les variables biométriques suivantes et leurs composants ont été mésurés : hauteur de la plante, nombre de feuilles, biomasse et rendement économique. Résultats. Les résultats suggèrent que FII est la fréquence d'irrigation optimale. Cette fréquence d'irrigation génère un peuplement adéquat à l'initiation des panicules et permet un développement correct de la plante avec des rendements biologiques et économiques optimaux et la meilleure efficacité d'utilisation de l'eau (4,02 kg·m-3). Conclusions. Cette étude a démontré le potentiel de culture de A. cruentus dans la basse vallée de la rivière Río Negro, représentant l'étude de la densité d’installation réalisée pour cette culture de céréales la plus australe au monde. Une gestion de l'eau d'irrigation de 7 jours pour la mise en place de la culture puis avec une fréquence de 14 jours a montré le rendement le plus élevé et la meilleure efficacité d'utilisation de l'eau.
Introduction. The production potential of grain amaranth has recently been demonstrated in northeastern Patagonia, Argentina. This crop under irrigation and in a temperate semi-arid climate showed an ...adequate development of the plants in their different phenological stages with high economic performance.Objectives. This study explored the response of Amaranthus cruentus cv Mexicano to different irrigation frequencies in the lower valley of Río Negro river, Patagonia, Argentina. Method. The experimental design was of three blocks with randomized treatments (subplots), each one corresponding to a different irrigation frequency. The first six irrigations were performed every 7 days for all the treatments, to ensure the establishment of the crop. Then the following treatments were applied: irrigation every 7 days (FI), every 14 days (FII), and every 21 days (FIII). The following biometric variables and their components were measured: height of plant, number of leaves, biomass and economic yield. Results. The results suggest that the optimum irrigation frequency was FII (14 days), resulting in an adequate plant stand at panicle initiation and allows a proper development of plant with optimal biological and economical yields and the highest efficiency of water use (4.02 kg·m-3). Conclusions. The contributions of this study demonstrated the production potential of A. cruentus crop in the lower valley of the Río Negro river under irrigation, representing the southernmost study on irrigation frequency made for this grain crop in the world. A management of irrigation water of 7 days for the establishment of the crop and then with a frequency of 14 days showed the highest yield and the best water use efficiency.
Fréquence d'irrigation de l'amarante dans le nord-est de la Patagonie, ArgentineIntroduction. Récemment, il a été démontré le potentiel de la culture d’amarante en Patagonie du Nord, en Argentine. Cette culture sous irrigation et en climat tempéré semi-aride a montré un développement adéquat des plantes dans leurs différents stades phénologiques avec des performances économiques élevéesObjectifs. Cette étude a exploré la réponse de Amaranthus cruentus cv Mexicano à une fréquence différente d’irrigation dans la basse vallée de la rivière Río Negro, en Patagonie, en Argentine.Méthode. Un modèle expérimental de trois blocs avec des traitements randomisés (sous-parcelles), chacun correspondant à différentes fréquences d'irrigation, a été appliqué. Les six premières irrigations pour tous les traitements effectués tous les 7 jours eurent pour but d'assurer l'implantation de la culture. Ensuite, la FI a maintenu cette fréquence, la FII tous les 14 jours et FIII tous les 21 jours. Les variables biométriques suivantes et leurs composants ont été mésurés : hauteur de la plante, nombre de feuilles, biomasse et rendement économique. Résultats. Les résultats suggèrent que FII est la fréquence d'irrigation optimale. Cette fréquence d'irrigation génère un peuplement adéquat à l'initiation des panicules et permet un développement correct de la plante avec des rendements biologiques et économiques optimaux et la meilleure efficacité d'utilisation de l'eau (4,02 kg·m-3).Conclusions. Cette étude a démontré le potentiel de culture de A. cruentus dans la basse vallée de la rivière Río Negro, représentant l'étude de la densité d’installation réalisée pour cette culture de céréales la plus australe au monde. Une gestion de l'eau d'irrigation de 7 jours pour la mise en place de la culture puis avec une fréquence de 14 jours a montré le rendement le plus élevé et la meilleure efficacité d'utilisation de l'eau.
Set Sprinkler Irrigation and Its Cost Ortiz Romero, José Nicolás; Montero Martínez, Jesús; Martínez, Roberto Simón ...
Journal of irrigation and drainage engineering,
10/2006, Letnik:
132, Številka:
5
Journal Article
Recenzirano
In this study, annual water application costs per unit area (ha) have been analyzed at the level of irrigation subunit in set sprinkler irrigation systems designed with pipes of different materials. ...In the cost, investment (pumping, pipes, sprinklers, ditches), energy, labor, maintenance, and water costs have been considered. Four systems were studied: one with buried pipes, in a permanent solid-set system, using: (a) polyvinyl chloride with buried pipes (PVCb), and three with pipes on the surface in surface solid-set systems, using (b) polyvinyl chloride pipes, (c) polyethylene pipes, and (d) aluminum pipes. The correct selection of the irrigation subunit size and shape can lead to a significant decrease in cost. The most economic irrigation subunits, among the four systems studied, were those formed by four laterals and a number of sprinklers per lateral of 10, 9, and 6 at
12
m×12
m
,
12
m×18
m
, and
18
m×18
m
spacing, respectively. The most influential factor on the annual water application cost was spacing. Considering total annual cost, water cost was the most important, followed by investment and energy. Among the analyzed systems, the permanent system using PVCb produced the lowest annual water application cost per unit area.
Abstract Human‐Centred Learning Analytics (HCLA) has emerged in the last 5 years as an active sub‐topic within Learning Analytics, drawing primarily on the theories and methods of Human‐Computer ...Interaction (HCI). HCLA researchers and practitioners are adopting and adapting HCI theories/methods to meet the challenge of meaningfully engaging educational stakeholders in the LA design process, evaluating systems in use and researching the sociotechnical factors influencing LA successes and failures. This editorial introduces the contributions of the papers in this special section, reflects more broadly on the field's emergence over the last five years, considers known gaps and indicates new opportunities that may open in the next five years.
We present a photometric study of the dwarf galaxy population in the core region ( rvir/4) of the Fornax galaxy cluster based on deep u′g′i′ photometry from the Next Generation Fornax Cluster Survey. ...All imaging data were obtained with the Dark Energy Camera mounted on the 4 m Blanco telescope at the Cerro Tololo Interamerican Observatory. We identify 258 dwarf galaxy candidates with luminosities −17 Mg′ −8 mag, corresponding to typical stellar masses of , reaching ∼3 mag deeper in point-source luminosity and ∼4 mag deeper in surface brightness sensitivity compared to the classic Fornax Cluster Catalog. Morphological analysis shows that the dwarf galaxy surface-brightness profiles are well represented by single-component Sérsic models with average Sérsic indices of and average effective radii of . Color-magnitude relations indicate a flattening of the galaxy red sequence at faint galaxy luminosities, similar to the one recently discovered in the Virgo cluster. A comparison with population synthesis models and the galaxy mass-metallicity relation reveals that the average faint dwarf galaxy is likely older than ∼5 Gyr. We study galaxy scaling relations between stellar mass, effective radius, and stellar mass surface density over a stellar mass range covering six orders of magnitude. We find that over the sampled stellar mass range several distinct mechanisms of galaxy mass assembly can be identified: (1) dwarf galaxies assemble mass inside the half-mass radius up to , (2) isometric mass assembly occurs in the range , and (3) massive galaxies assemble stellar mass predominantly in their halos at and above.
Explainable Artificial Intelligence in education Khosravi, Hassan; Shum, Simon Buckingham; Chen, Guanliang ...
Computers and education. Artificial intelligence,
2022, 2022-00-00, 2022-01-01, Letnik:
3
Journal Article
Recenzirano
Odprti dostop
There are emerging concerns about the Fairness, Accountability, Transparency, and Ethics (FATE) of educational interventions supported by the use of Artificial Intelligence (AI) algorithms. One of ...the emerging methods for increasing trust in AI systems is to use eXplainable AI (XAI), which promotes the use of methods that produce transparent explanations and reasons for decisions AI systems make. Considering the existing literature on XAI, this paper argues that XAI in education has commonalities with the broader use of AI but also has distinctive needs. Accordingly, we first present a framework, referred to as XAI-ED, that considers six key aspects in relation to explainability for studying, designing and developing educational AI tools. These key aspects focus on the stakeholders, benefits, approaches for presenting explanations, widely used classes of AI models, human-centred designs of the AI interfaces and potential pitfalls of providing explanations within education. We then present four comprehensive case studies that illustrate the application of XAI-ED in four different educational AI tools. The paper concludes by discussing opportunities, challenges and future research needs for the effective incorporation of XAI in education.
•The paper explores the role and need for explainable AI (XAI) in education.•We argue that XAI in education has commonalities with the broader use of AI but also has distinctive needs.•A framework based on six key aspects for studying and developing educational AI tools is proposed.•The application of the proposed framework is illustrated with four comprehensive case studies.•The paper concludes with an agenda for future research in XAI in education.
ABSTRACT We report the discovery of 158 previously undetected dwarf galaxies in the Fornax cluster central regions using a deep coadded u-, g-, and i-band image obtained with the Dark Energy Camera ...wide-field camera mounted on the 4-m Blanco telescope at the Cerro Tololo Interamerican Observatory as part of the Next Generation Fornax Survey (NGFS). The new dwarf galaxies have quasi-exponential light profiles, effective radii 0.1 < re < 2.8 kpc, and average effective surface brightness values 22.0 < i < 28.0 mag arcsec−2. We confirm the existence of ultra-diffuse galaxies (UDGs) in the Fornax core regions that resemble counterparts recently discovered in the Virgo and Coma galaxy clusters. We also find extremely low surface brightness NGFS dwarfs, which are several magnitudes fainter than the classical UDGs. The faintest dwarf candidate in our NGFS sample has an absolute magnitude of Mi = −8.0 mag. The nucleation fraction of the NGFS dwarf galaxy sample appears to decrease as a function of their total luminosity, reaching from a nucleation fraction of >75% at luminosities brighter than Mi −15.0 mag to 0% at luminosities fainter than Mi −10.0 mag. The two-point correlation function analysis of the NGFS dwarf sample shows an excess on length scales below ∼100 kpc, pointing to the clustering of dwarf galaxies in the Fornax cluster core.
We present the analysis of 61 nucleated dwarf galaxies in the central regions ( Rvir/4) of the Fornax galaxy cluster. The galaxies and their nuclei are studied as part of the Next Generation Fornax ...Survey using optical imaging obtained with the Dark Energy Camera mounted at Blanco/Cerro Tololo Inter-American Observatory and near-infrared data obtained with VIRCam at VISTA/ESO. We decompose the nucleated dwarfs in nucleus and spheroid, after subtracting the surface brightness profile of the spheroid component and studying the nucleus using point source photometry. In general, nuclei are consistent with colors of confirmed metal-poor globular clusters, but with significantly smaller dispersion than other confirmed compact stellar systems in Fornax. We find a bimodal nucleus mass distribution with peaks located at and ∼6.3. These two nucleus subpopulations have different stellar population properties: the more massive nuclei are older than ∼2 Gyr and have metal-poor stellar populations (Z ≤ 0.02 Z ), while the less massive nuclei are younger than ∼2 Gyr with metallicities in the range 0.02 < Z/Z ≤ 1. We find that the nucleus mass ( ) versus galaxy mass ( ) relation becomes shallower for less massive galaxies starting around 108 M , and the mass ratio shows a clear anticorrelation with for the lowest masses, reaching 10%. We test current theoretical models of nuclear cluster formation and find that they cannot fully reproduce the observed trends. A likely mixture of in situ star formation and star cluster mergers seems to be acting during nucleus growth over cosmic time.
ABSTRACT
We present a pilot study to assess the potential of Hyper Suprime-Cam Public Data Release 2 (HSC-PDR2) images for the analysis of extended faint structures within groups of galaxies. We ...examine the intragroup light (IGL) of the group 400138 (Mdyn = 1.3 ± 0.5 × 1013 M⊙, z ∼ 0.2) from the Galaxy And Mass Assembly (GAMA) survey using Hyper Suprime-Cam Subaru Strategic Program Public Data Release 2 (HSC-SSP PDR2) images in g, r, and i bands. We present the most extended IGL measurement to date, reaching down to $\mu _{g}^{\rm {lim}}=30.76$ mag arcsec−2 (3σ; 10 × 10 arcsec2) at a semimajor axis of 275 kpc. The IGL shows mean colour values of g − i = 0.92, g − r = 0.60, and r − i = 0.32 (±0.01). The IGL stellar populations are younger (2–2.5 Gyr) and less metal rich (Fe/H ∼ −0.4) than those of the host group galaxies. We find a range of IGL fractions as a function of total group luminosity of ${\sim} 2\!-\!36 {{\ \rm per\ cent}}$ depending on the definition of IGL, with larger fractions the bluer the observation wavelength. The early-type to late-type galaxy ratio suggests that 400138 is a more evolved group, dominated by early-type galaxies, and the IGL fraction agrees with that of other similarly evolved groups. These results are consistent with tidal stripping of the outer parts of Milky Way-like galaxies as the main driver of the IGL build-up. This is supported by the detection of substructure in the IGL towards the galaxy member 1660615 suggesting a recent interaction (<1 Gyr ago) of that galaxy with the core of the group.
The term Classroom Proxemics refers to how teachers and students use classroom space, and the impact of this and the spatial design on learning and teaching. This study addresses the divide between, ...on the one hand, substantial work on proxemics based on classroom observations and, on the other hand, emerging work to design automated feedback that helps teachers identify salient patterns in their use of the classroom space. This study documents how digital analytics were designed in service of a senior teacher's practice‐based inquiry into classroom proxemics. Indoor positioning data from four teachers were analysed, visualized and used as evidence to compare three distinct learning designs enacted in a physics classroom. This study demonstrates how teachers can make effective use of such visualizations, to gain insight into their classroom practice. This is evidenced by (a) documenting teachers' reflections on visualizations of positioning data, both their own and that of peers and (b) identifying the types of indicator (operationalized as analytical metrics) that foreground the most useful information for teachers to gain insight into their practice.
Lay Description
What is already known about this topic
The term “Classroom Proxemics” refers to how teachers and students use the classroom space, and its impact on learning.
A large number of teachers, particularly in higher education, receive no pedagogical training or feedback on classroom proxemics.
Little is known about how to create interfaces to enhance teachers' awareness, using automatic position tracking.
What this paper adds
Indoor positioning data from four teachers in a physics classroom are analysed.
Teachers' reflections on visual representations of teachers' positioning are documented.
Analytics of teachers' proxemics are identified from teachers' reflections.
Emerging themes included classroom territoriality, classroom space use according to the learning design, differences between teaching behaviours and temporality.
Implications for practitioners
The learning design and differences among teachers play a critical role in making sense of teachers' positioning data.
Analytics of classroom proxemics can create new opportunities to support professional development.
The use of positioning sensors in the classroom can provide evidence for teachers to reflect on improvement and how they approach students over time.
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