1,155 research outputs found
The financial sustainability of Microcredit in Portugal
Microcredit and microfinance emerged in the 1970âs in Bangladesh and other developing countries and expanded rapidly worldwide as a business model financially sustainable and able to fight poverty and social exclusion. Empirical evidence confirms microcredit ability to mitigate poverty but its financial sustainability is controversial. Using 2006-2009 Portuguese micro-level data, we estimate the failure rate of Portuguese micro-credit projects as 20,6%/year that, to be financially sustainable, would require a real interest rate by 25%/year. Using a territorial variable on a discrete Cox proportional hazard model with censured data, we estimate that the failure rate of those micro-credit projects located in the worst-case NUTS II Portuguese regions (Alentejo and Centro) and promoted by lower schooling people is significantly higher than best-case.Microcredit, Firms failure rate, Poverty, Financial sustainability
Knowledge Transfer for Melanoma Screening with Deep Learning
Knowledge transfer impacts the performance of deep learning -- the state of
the art for image classification tasks, including automated melanoma screening.
Deep learning's greed for large amounts of training data poses a challenge for
medical tasks, which we can alleviate by recycling knowledge from models
trained on different tasks, in a scheme called transfer learning. Although much
of the best art on automated melanoma screening employs some form of transfer
learning, a systematic evaluation was missing. Here we investigate the presence
of transfer, from which task the transfer is sourced, and the application of
fine tuning (i.e., retraining of the deep learning model after transfer). We
also test the impact of picking deeper (and more expensive) models. Our results
favor deeper models, pre-trained over ImageNet, with fine-tuning, reaching an
AUC of 80.7% and 84.5% for the two skin-lesion datasets evaluated.Comment: 4 page
Avaliação da situação nutricional dos soutos de castanheiro do distrito de Bragança através de anålises de terras e foliares
O castanheiro tem sido uma espécie fruteira cultivada em condiçÔes
marginais, sendo as ĂĄrvores raramente fertilizadas. Poucos estudos foram
dedicados Ă gestĂŁo da fertilidade do solo e ao estado nutricional desta
cultura. Este trabalho apresenta os resultados de anålises de populaçÔes de
1041 e 198 amostras de solos e folhas, respetivamente colhidas em nove
municĂpios no distrito de Bragança. Uma população suplementar de 80
amostras de solos, folhas e frutos foi ainda colhida nos trĂȘs municĂpios mais
produtivos do distrito de Bragança, estas nos mesmos pomares, para permitir
o estabelecimento de relaçÔes entre parùmetros de fertilidade do solo e do
estado nutricional das årvores. Os resultados das duas populaçÔes de solos
mostram elevada acidez, baixo teor de matéria orgùnica, baixo teor em
fĂłsforo e alto teor em potĂĄssio. Uma percentagem elevada de amostras de
folhas mostrou concentraçÔes de nutrientes abaixo do limite inferior do
intervalo de suficiĂȘncia, tanto na primeira como na segunda população de
amostras, para azoto (respetivamente 63% e 47%), fĂłsforo (18% e 15%),
potåssio (34% e 31 %), cålcio (19% e 52%), magnésio (21% e 13%) e boro (40%
e 43%). No caso do boro, 6% e 8% das amostras de folhas da primeira e
segunda populaçÔes apresentaram valores dentro do intervalo de
concentraçÔes excessivas. Os resultados deste trabalho revelaram ausĂȘncia
ou relaçÔes fracas entre propriedades e ou nutrientes disponĂveis no solo e a
concentração de nutrientes nas folhas. O estado nutricional dos soutos indica
que é urgente começar a aplicar programas regulares de fertilização,
principalmente com base na avaliação do estado nutricional das årvores
através da anålise de folhas.info:eu-repo/semantics/publishedVersio
Soil and plant analyses to diagnose hop fields irregular growth
In cultivated fields, patches of poorly developed vegetation often appear without a clear indication of what is affecting the growth
of the plants. The purpose of this study was to investigate the causes behind these irregularities in the hop (Humulus lupulus L.)
fields of NE Portugal which are greatly reducing crop yield and farmersâ profits and to provide guidance to farmers as to
appropriate remedial action. Patches of different levels of plant development were selected within hop fields and categorized
according to plant vigour (weak, fair and good). Several soil properties were determined and related to the plant nutritional status
and dry matter yield of different parts of the plant (hops, leaves, stems). Data was subjected to analysis of variance and principal
component analysis. The results suggest that crop yield is reduced mostly due to poor soil aeration and excessive soil and tissue
Mn and Fe levels. The plants fromthe plots of weaker vigour seem to be particularly affected by toxic levels of Mn and the plants
from the plots of fair vigour by Fe levels. pH, texture (clay content), cation exchange capacity and organic carbon seem to be
other soil properties with some degree of influence on plant performance. From these results, farmers are advised to increase soil
aeration by implementing a drainage systemand converting to a drip irrigation system, in addition to increasing soil pH by liming
to reduce Mn toxicity.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and European Regional Development Fund (ERDF) under Programme PT2020 for the financial support to CIMO (UIDB/00690/2020) and also the scholarship grant of
Sandra Afonso (number BD/116593/2016) under the Programme
PT2020 (UID/AGR/00690/2019).The authors are grateful to the Foundation for
Science and Technology (FCT, Portugal) and European Regional
Development Fund (ERDF) under Programme PT2020 for the financial
support to CIMO (UIDB/00690/2020) and also the scholarship grant of
Sandra Afonso (number BD/116593/2016) under the Programme
PT2020 (UID/AGR/00690/2019).info:eu-repo/semantics/publishedVersio
Agronomic and chemical evaluation of hop cultivars grown under Mediterranean conditions
Aim of study: Evaluation of the agronomic performance and chemical profile of four hop cultivars grown under Mediterranean conditions.
Area of study: The study was undertaken in Bragança, north-eastern Portugal.
Material and methods: The newly introduced cultivars (âColumbusâ, âCascadeâ and âCometâ) were compared with the well-stablished
âNuggetâ. The field experiment was carried out between 2017 and 2019. Dry matter (DM) yield (plant and cones), tissue elemental composition
and bitter acid and nitrate (NO3-) concentrations in the cones were assessed.
Main results: âCometâ was the most productive cultivar with the highest total DM yield (1,624 to 1,634 g plant-1), cone yield (572 to
633 g plant-1), and dry weight of individual cones (0.28 to 0.79 g cone-1). âCascadeâ showed the lowest average total DM yield (723 to 1,045
g plant-1). The year affected the average values of DM yield and the concentration of bitter acids in the cones, with âCascadeâ showing the
highest sensitivity between cultivars. The concentrations of α and ÎČ-acids in the cones were within or close to the normal ranges internationally
accepted for all cultivars. âColumbusâ exhibited the highest levels of α-acids, ranging between 12.04 % and 12.23%, followed by
âNuggetâ (10.17â11.90%), âCometâ (9.32â10.69%) and âCascadeâ (4.46â8.72%). The nutrient accumulation criteria in cone and leaf tissues
seem to be a differentiating factor between cultivars with influence on bitter acid biosynthesis and biomass production.
Research highlights: All cultivars showed notable performance in terms of DM yield and bitter acid concentration in the cones when
compared to international standards.Foundation for Science and Technology (FCT, Portugal) and the European Regional Development Fund, ERDF (Programme PT2020)
CIMO (UID/AGR/00690/2019)
Scholarship to Sandra Afonso (BD/116593/2016)info:eu-repo/semantics/publishedVersio
Twenty-years of hop irrigation by flooding the inter-row did not cause a gradient along the row in soil properties, plant elemental composition and dry matter yield
In hops (Humulus lupulus L.), irrigation by flooding the inter-row can carry away suspended
particles and minerals, causing gradients in soil fertility. The effect of more than 20 years of flooding
irrigation on soil and plants was evaluated in two hop fields by measuring soil and plant variables
in multiple points along the rows. In a second experiment 1000 kg ha1 of lime was applied and
incorporated into the soil to assess whether liming could moderate any gradient created by the
irrigation. At different sampling points along the rows, significant differences were recorded in soil
properties, plant elemental composition and dry matter yield, but this was not found to exist over a
continuous gradient. The variations in cone yield were over 50% when different sampling points
were compared. However, this difference cannot be attributed to the effect of irrigation, but rather
to an erratic spatial variation in some of the soil constituents, such as sand, silt and clay. Flooding
irrigation and frequent soil tillage resulted in lower porosity and higher soil bulk density in the
0.0â0.10 m soil layer in comparison to the 0.10â0.20 m layer. In turn, porosity and bulk density were
respectively positively and negatively associated with crop productivity. Thus, irrigation and soil
tillage may have damaged the soil condition but did not create any gradient along the row. The
ridge appeared to provide an important pool of nutrients, probably caused by mass flow due to the
evaporation from it and a regular supply of irrigation water to the inter-row. Liming raised the soil
pH slightly, but had a relevant effect on neither soil nor plants, perhaps because of the small amounts
of lime applied.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal)
for financial support from national funds FCT/MCTES, to CIMO (UIDB/AGR/00690/2020) and for
Sandra Afonsoâs doctoral scholarship (BD/116593/2016).info:eu-repo/semantics/publishedVersio
Response of hops to algae-based and nutrient-rich foliar sprays
Over recent years, some hopyards of northeast Portugal have presented poorly developed
plants and reduced productivity. In this study, an attempt was made to improve the homogeneity
of hop fields and restore their productivity by using plant biostimulants as foliar sprays. The
experimental apparatus included four field trials carried out in four plots of different plant vigour, as
evaluated by farmers over previous years (weak, fair, good and very good). The experiments were
arranged as a factorial of foliar treatment (two plant biostimulants containing extracts of seaweed
algae and an untreated control) and year (2017 and 2018). The plot and the year influenced greatly
almost all the measured variables related to tissue nutrient concentration and crop performance. In
the control plots, cone dry matter (DM) yield varied from 83.3 to 394.4 g plant1 from the weak to
the very good plots. In 2018, cone DM yield was significantly higher than in 2017. The use of foliar
sprays influenced less the elemental composition of plant tissue than the plot or the year. The use
of foliar sprays only increased significantly crop yield in the plot of weak plant vigour. The foliar
treatments did not increase - and -acid concentration in the cones; in the control treatment of the
most productive plot, the values were, respectively, 11.2 and 3.9%. Although seaweed extracts tend
to help plants cope with several abiotic and biotic stresses, they showed to be effective in mitigating
the stress that is affecting these plants, which probably is poor soil drainage caused by the flooding
irrigation system, only under conditions of severe stress.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal)
for financial support from national funds FCT/MCTES, to CIMO (UIDB/AGR/00690/2020) and for
Sandra Afonsoâs doctoral scholarship (BD/116593/2016).info:eu-repo/semantics/publishedVersio
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