397 research outputs found
Assessing the overall perceived quality of the undergraduate students
Purpose
- The paper is twofold aimed: (i) defining and validating a scale to assess the quality
of the university experienced by students and (ii) analyzing the role of the aforementioned di-
mensions and their impact on studentsâ satisfaction.
Methodology/Approach
- A survey of 2,557 undergraduate students that finished their degrees
in 2013 at universities located in the region of Catalonia has been analyzed using Structural
Equation Modeling (SEM). An exploratory analysis suggests the final dimensions that were
confirmed in a confirmatory analysis. The psychometric characteristics of the scale are provided
to show reliability and validity of the constructs.
An extra model (also using SEM) assesses the impact of these dimensions on overall satisfac-
tion.
Findings
- The quality is a multifactor construct composed by: (i) âsyllabusâ, which refers to
the quality of the learning methods and the coordination efforts through the whole study period;
(ii) âskills developmentâ, referring to the skills that students might acquire along their studies
and (iii) âservices and facilitiesâ of the university.
Moreover, the first and third factors act as âenablersâ for the second factor one. Nevertheless,
only âSyllabusâ dimension affects significantly on studentsâ satisfaction, whereas âservices and
facilitiesâ do not have a significant role, although they are necessary in order to provide a good
service.
Research Limitation/implication
- Although the sample is large enough to draw robust re-
sults, it is limited the Catalonia. The paper provides recommendations for university managers
and public administration authorities in order to allocate the available resources.
Originality/Value of paper
- In an era of global competition, universities are trying to adapt
to these new requirements by expanding they academic offer, introducing innovative teaching
methods, providing teaching resources to lecturers, and updating the general services of the
university among others. All these services will be considered when students evaluate their
experience at the university. The paper contributes with an assessment scale for the holistic
service provided by the university within the period that the student is in the university. These findings can be applied to help define attractive academic programs and provide useful insights
on how the supporting facilities should be designed to allow students take advantage of their
learning process at universities.Postprint (published version
CarvĂŁo pirogĂȘnico como condicionante substrato de mudas de Tachigali vulgaris L.G. Silva & H.C. Lima.
Este estudo teve como objetivo verificar a eficiĂȘncia de carvĂŁo vegetal pirogĂȘnico como condicionante de substrato para o desenvolvimento de mudas florestais de alto vigor, testando-se o carvoeiro (Tachigali vulgaris) como espĂ©cie representativa do Bioma Cerrado. Foram tomados como modelo de produtividade os solos de elevada capacidade de troca catiĂŽnica com Horizonte A antrĂłpico da AmazĂŽnia (Terras Pretas de Ăndio), ricos em carbono pirogĂȘnico derivado de carvĂŁo vegetal. O experimento foi realizado no viveiro da Universidade do Estado de Mato Grosso, no municĂpio de Nova Xavantina-MT. Foram utilizadas quatro concentraçÔes de carvĂŁo de eucalipto (Eucalyptus sp.) com 5; 12,5; 25 e 50% do volume total do substrato base e 0% como testemunha. Foi avaliada a porcentagem de emergĂȘncia no inĂcio do experimento. Durante oito meses, a cada 30 dias, foi contado o nĂșmero de folhas e medida a altura total das mudas. No oitavo mĂȘs foi medido o diĂąmetro do coleto e determinada Ă massa seca da raiz e da parte aĂ©rea. Os tratamentos e a testemunha apresentaram emergĂȘncia superior a 80%, nĂŁo havendo influĂȘncia do carvĂŁo. Entretanto, o carvĂŁo vegetal incrementou significativamente a altura das mudas, o nĂșmero de folhas, o diĂąmetro do coleto e a massa seca radicular e da parte aĂ©rea, o que ficou evidenciado pela forte correlação positiva com as concentraçÔes de carvĂŁo. Portanto, o carvĂŁo vegetal pirogĂȘnico Ă© uma alternativa viĂĄvel como condicionante de origem biolĂłgica do substrato para a produção de mudas potencialmente mais resistentes, requerimento importante para plantios em campo sob condiçÔes mais severas, como na recuperação de ĂĄreas degradadas no Bioma Cerrado
Edaphic, structural and physiological contrasts across Amazon Basin forest-savanna ecotones suggest a role for potassium as a key modulator of tropical woody vegetation structure and function
Sampling along a precipitation gradient in tropical South America extending from ca. 0.8 to 2.0 m ag-1, savanna soils had consistently lower exchangeable cation concentrations and higher C/N ratios than nearby forest plots. These soil differences were also reflected in canopy averaged leaf traits with savanna trees typically having higher leaf mass per unit area but lower mass-based nitrogen (Nm) and potassium (Km). Both Nm and Km also increased with declining mean annual precipitation (PA), but most area-based leaf traits such as leaf photosynthetic capacity showed no systematic variation with PA or vegetation type. Despite this invariance, when taken in conjunction with other measures such as mean canopy height, area-based soil exchangeable potassium content, [K]sa , proved to be an excellent predictor of several photosynthetic properties (including 13C isotope discrimination). Moreover, when considered in a multivariate context with PA and soil plant available water storage capacity (ΞP) as covariates, [K]sa also proved to be an excellent predictor of stand-level canopy area, providing drastically improved fits as compared to models considering just PA and/or ΞP. Neither calcium, nor magnesium, nor soil pH could substitute for potassium when tested as alternative model predictors (ÎAIC > 10). Nor for any model could simple soil texture metrics such as sand or clay content substitute for either [K]sa or ΞP. Taken in conjunction with recent work in Africa and the forests of the Amazon Basin, this suggests-in combination with some newly conceptualised interacting effects of PA and ΞP also presented here-a critical role for potassium as a modulator of tropical vegetation structure and function.Natural Environment Research Council (NERC) TROBIT Consortium projectCNPqRoyal Society of London - Wolfson Research Merit Awar
Soil water-holding capacity and monodominance in Southern Amazon tropical forests
Background and aims: We explored the hypothesis that low soil water-holding capacity is the main factor driving the monodominance of Brosimum rubescens in a monodominant forest in Southern Amazonia. Tropical monodominant forests are rare ecosystems with low diversity and high dominance of a single tree species. The causes of this atypical condition are still poorly understood. Some studies have shown a relationship between monodominance and waterlogging or soil attributes, while others have concluded that edaphic factors have little or no explanatory value, but none has accounted for soil-moisture variation other than waterlogging. This study is the first to explicitly explore how low soil water-holding capacity influences the monodominance of tropical forests.
Methods: We conducted in situ measurements of vertical soil moisture using electrical resistance collected over 1 year at 0â5; 35â40 and 75â80 cm depths in a B. rubescens monodominant forest and in an adjacent mixed-species forest in the Amazon-Cerrado transition zone, Brazil. Minimum leaf water potential (Κmin) of the seven most common species, including B. rubescens, and soil water-holding capacity for both forests were determined.
Results: The vertical soil moisture decay pattern was similar in both forests for all depths. However, the slightly higher water availability in the monodominant forest and Κmin similarity between B. rubescens and nearby mixed forest species indicate that low water-availability does not cause the monodominance.
Conclusions: We reject the hypothesis that monodominance of B. rubescens is primarily determined by low soil water-holding capacity, reinforcing the idea that monodominance in tropical forests is not determined by a single factor
Utilização de um vetor viral para expressão ectópica do gene MrRGA8 em videira.
O mĂldio (Plasmopara viticola) Ă© a principal doença fĂșngica da videira. As cultivares de Vitis vinifera sĂŁo suscetĂveis Ă infecção por P. viticola, enquanto espĂ©cies selvagens, como a Muscadinia rotundifolia apresentam resistĂȘncia a este fungo
Savanna turning into forest: concerted vegetation change at the ecotone between the Amazon and âCerradoâ biomes
In the âCerradoââAmazon ecotone in central Brazil, recent studies suggest some encroachment of forest into savanna, but how, where, and why this might be occurring is unclear. To better understand this phenomenon, we assessed changes in the structure and dynamics of tree species in three vegetation types at the âCerradoââAmazon ecotone that are potentially susceptible to encroachment: open âcerradoâ (OC), typical âcerradoâ (TC) and dense woodland (DW). We estimated changes in density, basal area and aboveground biomass of trees with diameterââ„â10 cm over four inventories carried out between 2008 and 2015 and classified the species according to their preferred habitat (savanna, generalist, or forest). There was an increase in all structural parameters assessed in all vegetation types, with recruitment and gains in basal area and biomass greater than mortality and losses. Thus, there were net gains between the first and final inventories in density (OC: 3.4â22.9%; TC: 1.8â12.6%; DW: 0.2â8.3%), in basal area (OC: 8.3â18.2%; TC: 2â12.7%; DW: 2.3â8.9%), and in biomass (OC: 10.6â16.4%; TC: 1â12%; DW: 5.2â18.7%). Furthermore, all vegetation types also experienced net gains in forest and generalist species relative to savanna species. A decline in recruitment of savanna species was a likely consequence of vegetation encroachment and environmental changes. Our results indicate, for the first time based on quantitative and standardized multi-site temporal data, that concerted structural changes caused by vegetation encroachment are occurring at the ecotone between the two largest biomes in Brazil
Climate and crown damage drive tree mortality in southern Amazonian edge forests
This is the final version. Available on open access from Wiley via the DOI in this recordData availability statement: The data are available as a data package on ForestPlots.net: https://doi.org/10.5521/forestplots.net/2022_1 (Reis et al., 2022). The tree-level data used in Figure 5 are available on request from ForestPlot.net: https://www.forestplots.net/en/join-forestplots/working-with-dataTree death is a key process for our understanding of how forests are and will respond to global change. The extensive forests across the southern Amazonia edgeâthe driest, warmest and most fragmented of the Amazon regionsâprovide a window onto what the future of large parts of Amazonia may look like. Understanding tree mortality and its drivers here is essential to anticipate the process across other parts of the basin. Using 10Â years of data from a widespread network of long-term forest plots, we assessed how trees die (standing, broken or uprooted) and used generalised mixed-effect models to explore the contribution of plot-, species- and tree-level factors to the likelihood of tree death. Most trees died from stem breakage (54%); a smaller proportion died standing (41%), while very few were uprooted (5%). The mortality rate for standing dead trees was greatest in forests subject to the most intense dry seasons. While trees with the crown more exposed to light were more prone to death from mechanical damage, trees less exposed were more susceptible to death from drought. At the species level, mortality rates were lowest for those species with the greatest wood density. At the individual tree level, physical damage to the crown via branch breakage was the strongest predictor of tree death. Synthesis. Wind- and water deficit-driven disturbances are the main causes of tree death in southern Amazonia edge which is concerning considering the predicted increase in seasonality for Amazonia, especially at the edge. Tree mortality here is greater than any in other Amazonian region, thus any increase in mortality here may represent a tipping point for these forests
Drought generates large, long-term changes in tree and liana regeneration in a monodominant Amazon forest
The long-term dynamics of regeneration in tropical forests dominated by single tree species remains largely undocumented, yet is key to understanding the mechanisms by which one species can gain dominance and resist environmental change. We report here on the long-term regeneration dynamics in a monodominant stand of Brosimum rubescens Taub. (Moraceae) at the southern border of the Amazon forest. Here the climate has warmed and dried since the mid-1990âČs. Twenty-one years of tree and liana regeneration were evaluated in four censuses in 30 plots by assessing species abundance, dominance, and diversity in all regeneration classes up to 5 cm diameter. The density of B. rubescens seedlings declined markedly, from 85% in 1997 to 29% in 2018 after the most intense El Niño-driven drought. While the fraction contributed by other tree species changed little, the relative density of liana seedlings increased from just 1 to 54% and three-quarters of liana species underwent a ten-fold or greater increase in abundance. The regeneration community experienced a high rate of species turnover, with changes in the overall richness and species diversity determined principally by lianas, not trees. Long-term maintenance of monodominance in this tropical forest is threatened by a sharp decline in the regeneration of the monodominant species and the increase in liana density, suggesting that monodominance will prove to be a transitory condition. The close association of these rapid changes with drying indicates that monodominant B. rubescens forests are impacted by drought-driven changes in regeneration, and therefore are particularly sensitive to climatic change
Modeling Sustainability Reporting with Ternary Attractor Neural Networks
International Conference on Mining Intelligence and Knowledge Exploration. Cluj-Napoca, Romania, December 20â22, 2018This work models the Corporate Sustainability General Reporting
Initiative (GRI) using a ternary attractor network. A dataset of
years evolution of the GRI reports for a world-wide set of companies was
compiled from a recent work and adapted to match the pattern coding for
a ternary attractor network. We compare the performance of the network
with a classical binary attractor network. Two types of criteria were used
for encoding the ternary network, i.e., a simple and weighted threshold,
and the performance retrieval was better for the latter, highlighting the
importance of the real patternsâ transformation to the three-state coding.
The network exceeds the retrieval performance of the binary network for
the chosen correlated patterns (GRI). Finally, the ternary network was
proved to be robust to retrieve the GRI patterns with initial noise.This work has been supported by Spanish grants MINECO
(http://www.mineco.gob.es/) TIN2014-54580-R, TIN2017-84452-R, and by UAMSantander CEAL-AL/2017-08, and UDLA-SIS.MG.17.02
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