1,360 research outputs found
SALT STRESS ON THE PHYSIOLOGICAL QUALITY OF Cryptostegia madagascariensis Bojer ex Decne. SEEDS
A esp\ue9cie Cryptostegia madagascariensis Bojer ex Decne. foi
introduzida no Brasil com fins ornamentais, mas, atualmente, \ue9 uma
invasora do bioma Caatinga. Apesar de sua elevada capacidade de
ocupa\ue7\ue3o de \ue1reas alteradas do referido bioma, h\ue1
car\ueancia de informa\ue7\uf5es sobre esta esp\ue9cie,
particularmente em rela\ue7\ue3o \ue0 capacidade de suas sementes
germinarem em condi\ue7\uf5es adversas. O objetivo deste trabalho
foi avaliar a germina\ue7\ue3o de sementes e o crescimento inicial
de pl\ue2ntulas de Cryptostegia madagascariensis em fun\ue7\ue3o
da salinidade em diferentes temperaturas. O experimento foi realizado
seguindo um delineamento inteiramente casualizado, com os tratamentos
distribu\ueddos em esquema fatorial 6 x 3, sendo seis n\uedveis de
salinidade promovidos pelo cloreto de s\uf3dio (NaCl): 0,0
(controle); 2,0; 4,0; 6,0; 8,0 e 10,0 dS m-1; e tr\ueas temperaturas:
25 e 30\ub0C constantes e alternada de 20-35\ub0C. A qualidade
fisiol\uf3gica das sementes foi avaliada pelas seguintes
vari\ue1veis: germina\ue7\ue3o, primeira contagem e \uedndice
de velocidade de germina\ue7\ue3o, comprimento e massa seca de
ra\uedzes e do hipoc\uf3tilo. Os resultados obtidos indicam que
h\ue1 elevada probabilidade de germina\ue7\ue3o de sementes de
Cryptostegia madagascariensis submetidas a estresse salino em
temperatura constante de 30\ub0C e alternada de 20-35\ub0C, o que
potencializa o seu car\ue1ter invasor.The Cryptostegia madagascariensis Bojer ex Decne. species was
introduced in Brazil with ornamental purposes, but currently, it is
invasive in the Caatinga biome. Despite its high level of occupancy of
altered areas of Caatinga, there is lack of information about this
species, particularly in relation to the capacity of its seeds to
germinate in adverse conditions. The objective of this study was to
evaluate seed germination and the initial seedling growth of
Cryptostegia madagascariensis in function of salinity at different
temperatures. The experiment was conducted following a completely
randomized design, with treatments arranged in a 6 x 3 factorial design
with six salinity levels promoted by sodium chloride (NaCl): 0.0
(control); 2.0; 4.0; 6.0; 8.0 and 10.0 dS m-1 and three temperatures:
25 and 30\ub0C constant and alternating 20-35\ub0C. The
physiological quality of seeds was evaluated using the following
variables: germination, first count and the speed of germination index,
length and dry weight of roots and hypocotyl. The results indicate that
there is high probability of seed germination of Cryptostegia
madagascariensis subjected to salt stress at constant temperature of
30\ub0C and alternating 20-35\ub0C, which enhances its invasive
character
SEEDLINGS PRODUCTION OF UMBUZEIRO ( Spondias tuberosa Arruda C\ue2mara) IN DIFFERENT SUBSTRATES AND SIZE OF BAGS
A esp\ue9cie Spondias tuberosa Arr. Cam. (umbuzeiro) destaca-se
como uma das esp\ue9cies arb\uf3reas de maior potencial do
semi\ue1rido brasileiro. Apesar de sua relevante import\ue2ncia
socioecon\uf4mica e ambiental, h\ue1 falta de estudos voltados para
o estabelecimento de um modelo de produ\ue7\ue3o de mudas da
esp\ue9cie. O objetivo desse trabalho foi avaliar a
produ\ue7\ue3o de mudas de Spondias tuberosa utilizando diferentes
substratos e tamanho de recipientes. O experimento foi conduzido no
viveiro do Laborat\uf3rio de Ecologia Vegetal (LEV) do Centro de
Ci\ueancias Agr\ue1rias (CCA) da Universidade Federal da
Para\uedba (UFPB), Areia - PB. O delineamento experimental usado foi
em blocos casualizados em esquema fatorial 2 x 7 e parcelas
subdivididas, sendo que os recipientes representaram as parcelas e os
substratos as subparcelas. Foram utilizados substratos formulados a
partir da mistura de terra de subsolo (37,5-100%), areia lavada (12,5-
25%) e esterco bovino curtido (10-50%). Os recipientes utilizados foram
sacos de polietileno preto com volumes de 1900 cm3 (15 x 27 cm) e 5000
cm3 (25 x 26 cm). Para a obten\ue7\ue3o das pl\ue2ntulas,
sementes de Spondias tuberosa foram semeadas em sementeira de alvenaria
at\ue9 a repicagem (90 dias ap\uf3s o semeio). Aos 78 dias,
ap\uf3s a repicagem, as mudas foram avaliadas quanto \ue0 altura,
di\ue2metro do colo, rela\ue7\ue3o altura/ di\ue2metro do colo,
di\ue2metro do xilop\uf3dio, comprimento de raiz, massa seca da
parte a\ue9rea e raiz. Os dados obtidos foram submetidos \ue0
an\ue1lise de vari\ue2ncia e ao teste F, sendo as m\ue9dias
comparadas pelo teste de Tukey ao n\uedvel de 5% de probabilidade,
utilizando o software SISVAR\uae. Os substratos com esterco bovino
curtido proporcionaram os maiores valores em altura e comprimento de
raiz. Para a produ\ue7\ue3o de mudas de Spondias tuberosa, \ue9
recomendado o substrato contendo terra de subsolo (45%) + Areia (15%) +
Esterco bovino (40%).The species Spondias tuberosa Arr. Cam. (umbuzeiro) stands out as one
of the tree species with the greatest potential of the Brazilian
semiarid. Even though it\u2019s significant socioeconomic and
environmental importance, there is a lack of studies aimed at
establishing a seedlings production model of this kind of plant. The
purpose of this study was to evaluate the production of seedlings
Spondias tuberosa using different substrates and size of bags. The
experiment was conducted in the nursery of the Plant Ecology Laboratory
(LEV) from the Agrarian Sciences Center (CCA) of the Federal University
of Paraiba (UFPB), Areia/ PB. The experimental design was a randomized
block in factorial 2 x 7 and subdivided blocks containersplots and
subplots substrates. It were used substrates formulated from the
starting mixture of subsoil land (37.5-100%), sand (12.5-25%) and
tanned cattle manure (10-50%). The containers used were black
polyethylene bags with a volume of 1900 cm3 (15 x 27 cm) and 5000 cm3
(25 x 26 cm). To obtain seedlings of Spondias tuberosa seeds were sown
in seed masonry until the transplant (90 days after sowing). At 78 days
after transplanting the seedlings were evaluated for height, root
collar diameter, relationship shoot/root collar diameter, xylopodium
diameter, root length, dry weigh of shoot and root. The datas were
subjected to analysis of variance and F test, measured and compared by
Tukey test at 5% probability, using the software SISVAR\uae. The
substrates with cattle manure provided higher values for height and
root length. For the seedlings production of Spondias tuberosa, is
recommended substrate subsoil land (45%) + sand (15%) + cattle manure
(40%)
Analysis of cold formed structural rack columns.
Este trabalho avalia a ocorr?ncia do modo de associado a flambagem local em pilares curtos
constitu?das por perfis formados a frio tipo rack. Estes pilares possuem perfura??es para
facilitar a montagem, e este trabalho considera a influ?ncia das mesmas no comportamento e
no esfor?o resistente destes perfis estruturais. Os estudos foram realizados por an?lises
num?ricas e experimentais, cujos resultados apresentaram boa correla??o e indicaram que as
perfura??es n?o afetaram significativamente a carga cr?tica e a capacidade resistente dos
pilares, apesar de influenciarem significativamente o comportamento dos mesmos, alterando
o n?mero de meias ondas formadas. Observou-se ainda consider?vel influ?ncia das
imperfei??es geom?tricas no comportamento da estrutura, indicando a necessidade de sua
inclus?o nas an?lises num?ricas.This work presents an evaluation of local buckling in cold formed rack stub columns. These
columns have perforations along their length to make assemblage easier, and this research
investigates their influence in these structures behavior and resistance. Experimental end
numerical analysis were carried out and their results showed good agreement and indicated
that perforations in columns don't reduce significantly their buckling load and strength, but
affect their buckling modes by changing the number of half waves formed in the columns . It
was also observed a considerable influence of geometrical imperfections, indicating the need
of their inclusion in the numerical analysis
Search for new neutral Higgs bosons through the H → ZA→ ℓ+ℓ−b b ¯ process in pp collisions at √s = 13 TeV
This paper reports on a search for an extension to the scalar sector of the standard model, where a new CP-even (odd) boson decays to a Z boson and a lighter CP-odd (even) boson, and the latter further decays to a b quark pair. The Z boson is reconstructed via its decays to electron or muon pairs. The analysed data were recorded in proton-proton collisions at a center-of-mass energy s = 13 TeV, collected by the CMS experiment at the LHC during 2016, corresponding to an integrated luminosity of 35.9 fb−1. Data and predictions from the standard model are in agreement within the uncertainties. Upper limits at 95% confidence level are set on the production cross section times branching fraction, with masses of the new bosons up to 1000 GeV. The results are interpreted in the context of the two-Higgs-doublet model. [Figure not available: see fulltext.]
Framingham coronary heart disease risk score can be predicted from structural brain images in elderly subjects
Recent literature has presented evidence that cardiovascular risk factors (CVRF) play an important role on cognitive performance in elderly individuals, both those who are asymptomatic and those who suffer from symptoms of neurodegenerative disorders. Findings from studies applying neuroimaging methods have increasingly reinforced such notion. Studies addressing the impact of CVRF on brain anatomy changes have gained increasing importance, as recent papers have reported gray matter loss predominantly in regions traditionally affected in Alzheimer’s disease (AD) and vascular dementia in the presence of a high degree of cardiovascular risk. In the present paper, we explore the association between CVRF and brain changes using pattern recognition techniques applied to structural MRI and the Framingham score (a composite measure of cardiovascular risk largely used in epidemiological studies) in a sample of healthy elderly individuals. We aim to answer the following questions: is it possible to decode (i.e., to learn information regarding cardiovascular risk from structural brain images) enabling individual predictions? Among clinical measures comprising the Framingham score, are there particular risk factors that stand as more predictable from patterns of brain changes? Our main findings are threefold: (i) we verified that structural changes in spatially distributed patterns in the brain enable statistically significant prediction of Framingham scores. This result is still significant when controlling for the presence of the APOE 4 allele (an important genetic risk factor for both AD and cardiovascular disease). (ii) When considering each risk factor singly, we found different levels of correlation between real and predicted factors; however, single factors were not significantly predictable from brain images when considering APOE4 allele presence as covariate. (iii) We found important gender differences, and the possible causes of that finding are discussed
Conservation of marizeiro Geoffroea spinosa Jacq. seeds using different packagings and environments
O marizeiro ( Geoffroea spinosa Jacq.) \ue9 uma esp\ue9cie
florestal importante, sobretudo por ser adaptada \ue0s
condi\ue7\uf5es de matas ciliares do semi-\ue1rido e ecossistemas
associados, ocorrendo em vastas \ue1reas do Nordeste brasileiro e no
vale do rio S\ue3o Francisco, sempre restrita a ambientes
sazonalmente inundados. Este trabalho teve como objetivos avaliar o
efeito de diferentes tipos de embalagens e do per\uedodo de
armazenamento sobre o processo germinativo e o vigor de sementes de
Geoffroea spinosa Jacq. acondicionadas tamb\ue9m em diferentes
ambientes. O experimento foi instalado no Laborat\uf3rio de Ecologia
Vegetal do CCA/UFPB, seguindo um delineamento inteiramente casualizado.
As sementes foram distribu\ueddas em dois ambientes
(condi\ue7\uf5es naturais, no laborat\uf3rio e c\ue2mara fria),
acondicionadas em dois tipos de embalagens (sacos de papel e sacos
pl\ue1sticos) durante cinco per\uedodos de armazenamento: 0, 15,
30, 60 e 90 dias. Foram avaliados o teor de \ue1gua, o \uedndice de
velocidade de emerg\ueancia, a massa seca e o comprimento de
pl\ue2ntulas. Os dados foram submetidos \ue0 an\ue1lise de
regress\ue3o polinomial. Na embalagem pl\ue1stica e no ambiente de
c\ue2mara fria, houve menor redu\ue7\ue3o da viabilidade e do
vigor ao longo do armazenamento. As sementes acondicionadas em sacos de
papel e armazenadas em ambiente de laborat\uf3rio perderam
rapidamente a viabilidade e o vigor a partir dos 30 dias de
armazenamento.Geoffroea spinosa Jacq., commonly known as marizeiro in Brazil, is an
important tree species, mainly because it is adapted to riparian forest
conditions in semi-arid and associated ecosystems. The species occur in
large areas of northeastern Brazil and in the S\ue3o Francisco river
valley, always restricted to seasonally flooded environments. This
study aimed to evaluate the effect of different types of packaging and
storage periods, as well the influence of environments on the process
of seed germination and vigor of Geoffroea spinosa. The experiment was
carried out at the Laboratory of Plant Ecology - CCA/UFPB, following a
completely randomized design. The seeds were distributed among two
environments (natural conditions in the laboratory and cold room),
packed in two types of packaging (paper bags and plastic bags) for five
periods of storage: 0; 15; 30; 60 and 90 days. Water content, the
emergence velocity index, dry weight and length of seedlings were
evaluated. The data were submitted to a polynomial regression analysis.
In plastic packaging and the environment of the cold room there was
less reduction of viability and vigor during storage. Seeds packed in
paper bags and stored in a laboratory rapidly lost viability and vigor,
after 30 days of storage
Morphometric characterization of fruits and seeds and the effect of the temperature on germination of Parkia pendula (Willd.) Benth. ex Walp
Parkia pendula (Willd.) Benth. ex Walp., \ue9 uma esp\ue9cie
arb\uf3rea, caracter\uedstica dos est\ue1dios iniciais da
sucess\ue3o, de ocorr\ueancia natural no Brasil. Pertence \ue0
fam\uedlia Fabaceae, com grande potencial na recupera\ue7\ue3o de
\ue1reas degradadas. O presente trabalho foi conduzido no Centro de
Ci\ueancias Agr\ue1rias da Universidade Federal de Alagoas,
objetivando a caracteriza\ue7\ue3o morfom\ue9trica de frutos e
sementes dessa esp\ue9cie, bem como identificar a melhor temperatura
para uso em testes de germina\ue7\ue3o. O fruto \ue9 do tipo
legume, deiscente, polisp\ue9rmico, contendo em m\ue9dia 16
sementes por unidade. Estas apresentam formato elipsoidal, embri\ue3o
axial, com 10,1 mm de comprimento, 4,9 mm de largura por 3,1mm de
espessura. As temperaturas de 25 e 30oC proporcionaram as maiores
porcentagem e velocidade de germina\ue7\ue3o, enquanto que a
temperatura de 15oC e acima de 35\ubaC influenciaram negativamente a
germinabilidade das sementes.Parkia pendula (Willd.) Benth. ex Walp. is a tree species,
characteristic of the initial phases of succession, of natural
occurrence in Brazil. It belongs to the Mimosaceae family, with great
potential in the recovery of degraded areas. The present work aims to
characterize fruits and seeds morphometrically as well to identify the
best temperature for use in germination test. The fruit is a type of
legume, dehiscent, polispermic, with 16 seeds, approximately, per unit.
The seeds present ellipsoidal format, axial embryo, with 10,1 mm of
length, 4,9 mm of width and 3,1 mm of thickness. The temperatures of
25\ubaC and 30\ubaC provided them larger germinability, while the
temperature of 15\ubaC and above 35\ubaC influenced these
characteristics negatively
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