312 research outputs found
Genotypic variation in morphology and freezing resistance of Eucalyptus globulus seedlings subjected to drought hardening in nursery
Eucalyptus globulus Labill is one of the most planted species in
Chile, because of its fast growth and superior pulp qualities.
Nevertheless, the incidence of drought and frost damage immediately
after planting is frequent. The purpose of this work was to study the
effect of drought hardening on frost resistance and on variations in
morphological traits that may increase drought resistance at nursery
phase in four genotypes of E. globulus Labill. Drought hardening
treatments consisted in induced water stress by watering restriction,
until pre-dawn stem xylem water potentials (\u3a8pd) reached -0.2,
-1.8 and -2.6 MPa. Two water stress-rewatering cycles were applied
during 54 days of hardening. Plant and root biomasses were affected by
the interaction of drought hardening and genotypes. The rest of
morphological and alometrical traits were affected independently by
drought or genotype. Plant height, leaf area, specific leaf area (SLA),
stem, and leaf biomasses decreased with drought hardening, while collar
diameter was not affected. Genotypes responded differentially to
drought hardening in plant height, leaf area, SLA, and stem, and leaf
biomasses. Ice nucleation temperature (INT), and freezing temperatures
(FRT), and 50% freezing damage index of leaves (LT50) were affected by
the interaction between drought hardening and genotypes. EG-13, EG-23
and EG-22 genotypes became freezing tolerant with drought hardening
(-2.6 MPa). Additionally, EG-14 genotype increased its freezing
resistance at -1.8 MPa. Therefore, freezing resistance levels and
mechanism depend on genotype and drought hardening treatment. The
success in tree breeding by genetic selection should be facilitated by
improved understanding of the physiology of stress resistance
development and survival during water supply limitations. The knowledge
of morphological and freezing resistance dependency on the interaction
between genotype and drought hardening may be useful nursery management
information to improve plantation success
Changes in morpho-physiological attributes of Eucalyptus globulus plants in response to different drought hardening treatments
Morpho-physiological attributes exhibited in response to drought
hardening at the end of the growing season of Eucalyptus globulus
Labill under nursery conditions were studied to evaluate the effect of
three drought hardening treatments in morpho-physiological traits used
as suitable indicators of drought hardiness, such as, plant growth,
root growth potential, plant water relationships and survival. Freezing
resistance of drought hardened plants was also studied in order to
evaluate cross hardening effects in cuttings of Eucalyptus globulus
Labill. Drought hardening consisted in induced water stress by watering
restriction, until plant stem xylem water potentials (\u3a8pd) reached
to-0.2, -1.3 and -2.4 MPa. Two water stress-rewatering cycles were
applied during 54 days of treatment. The hardening treatments caused a
significant reduction in plant height, leaf area, specific leaf area,
plant, leaf, stem and root biomass. However, stem diameter was not
affected. Root growth potential increased with the exposure to moderate
water stress (-1.3 MPa). Drought hardening treatments have not effect
on water relationship parameters such as saturation osmotic potential
(\u3a8\u3c0sat), volumetric module of elasticity (e), relative water
content (RWCtlp) and osmotic potential (\u3a8\u3c0tlp) at the turgor
loss point. Only 1.7% and 6% of dehydrated dead plants were observed on
treatments at -1.3 and -2.4 MPa respectively. Finally, the freezing
damage index of leaves (LT50) was not significantly affected by drought
hardening treatments. Furthermore, a reduction of 1.1\ubaC of
supercooling capacity was observed at -2.4 MPa. As a conclusion,
drought hardening is an important step of plants production programs
during the final phase of nursery, because changes in morphological
attributes caused by exposure to moderate drought, enable the plants to
maintain the balance between transpiration and absorption areas and
increase the capacity of plants to generate new roots
Comparison of fiber effect on glycemic index and glycemic load in differents types of bread
IndexaciĂłn: Scopus; Redalyc.Existen diversos alimentos que contienen como nutriente
principal hidratos de carbono, destacando entre ellos el pan
por su masivo consumo a nivel mundial. Numerosos estudios
se han llevado a cabo con el fin de reducir su Ăndice glicĂ©mico,
sin embargo, aĂșn existe controversia sobre la acciĂłn de
la fibra dietética en la disminución del IG en este alimento.
Este estudio determinó el efecto de la fibra dietética sobre el
Ăndice glicĂ©mico y carga glicĂ©mica en dos tipos de panes comerciales
en 23 individuos sanos quienes consumieron aleatoriamente
3 diferentes productos, de 50 g de carbohidratos
cada uno, durante 6 dĂas: pan blanco (PH), pan integral (PF),
y soluciĂłn glucosada como producto de referencia (SG). Se
midiĂł glicemia en ayunas y post-prandial a los tiempos 15,
30, 45, 60, 90 y 120 min. La insulina fue medida en el minuto
0 y 120 min. El ĂĄrea bajo la curva de glicemia resultĂł
mås baja para ambos tipos de pan PH 13589 ±1557, PF
12005 ±1254 que para el producto de referencia SG 14089
±1245. Los valores del Ăndice glicĂ©mico PH 68,55 ±1,2 y PF
62,10 ±1,3 y carga glicémica PH 16,45 ±1,4 resultaron mås
bajos para el pan con mayor aporte de fibra 9,93 ± 1,1, sin
diferencias en la concentraciĂłn de insulina, sugiriendo que
la cantidad de carbohidratos y tipo de fibra contenidos en el
pan integral, pueden considerarse factores intrĂnsecos en su
composición nutricional, capaces de afectar la respuesta glicémica
post- ingesta de estos productos en individuos sanos.There are several foods that contain carbohydrates as the
main nutrient, being one of the most important the bread for
its massive worldwide consumption. Numerous studies have
been done in order to reduce its glycemic index, however
there is still controversy about the action of dietary fiber in the
decrease of GI in this product. In this study, it was determined
the effect of dietetic fiber on glycemic index and glycemic load
in two types of commercial breads in 23 healthy individuals
who randomly consumed 3 different products during 6 days
of 50g of carbohydrates each: white bread (PH), whole wheat
bread (PE) and glucose solution as reference product (SG).
Fasting and postprandial glycemia was measured at times
15, 30, 45, 60, 90 and 120 minutes. Insuline was measured
at 0 min and 120 min. The area under de glycemia curve
was lower for both bread types PH 13589 ±1557, PF 12005
±1254 than for the reference product SG 14089 ±1245. The
values of the glycemic index PH 68,55 ±1,2 and PF 62,01
±1,3 and glycemic load PH 16.45 ±1,4 were lower for bread
with more amount fiber 9,93 ± 1,1, with no difference in insulin
concentration, suggesting that the amount of carbohydrates
and fiber type contained in whole wheat bread can
be considered intrinsic factors in bread composition, affecting
the post-intake glycemic response of this type of products in
healthy individuals.http://www.redalyc.org/articulo.oa?id=5594990800
Trends in the Statistical Assessment of Reliability
Changes in technology have had and will continue to have a strong effect on changes in the area of statistical assessment of reliability data. These changes include higher levels of integration in electronics, improvements in measurement technology and the deployment of sensors and smart chips into more products, dramatically improved computing power and storage technology, and the development of new, powerful statistical methods for graphics, inference, and experimental design and reliability test planning. This paper traces some of the history of the development of statistical methods for reliability assessment and makes some predictions about the future
Locus coeruleus at asymptomatic early and middle Braak stages of neurofibrillary tangle pathology
Aims: the present study analyses molecular characteristics of the locus coeruleus (LC) and projections to the amygdala and hippocampus at asymptomatic early and middle Braak stages of neurofibrillary tangle (NFT) pathology. Methods: immunohistochemistry, whole-transcriptome arrays and RT-qPCR in LC and western blotting in hippocampus and amygdala in a cohort of asymptomatic individuals at stages I-IV of NFT pathology were used. Results: NFTs in the LC increased in parallel with colocalized expression of tau kinases, increased neuroketal adducts and decreased superoxide dismutase 1 in neurons with hyperphosphorylated tau and decreased voltage-dependent anion channel in neurons containing truncated tau were found. These were accompanied by increased microglia and AIF1, CD68, PTGS2, IL1ÎČ, IL6 and TNF-α gene expression. Whole-transcriptome arrays revealed upregulation of genes coding for proteins associated with heat shock protein binding and genes associated with ATP metabolism and downregulation of genes coding for DNA-binding proteins and members of the small nucleolar RNAs family, at stage IV when compared with stage I. Tyrosine hydroxylase (TH) immunoreactivity was preserved in neurons of the LC, but decreased TH and increased α2A adrenergic receptor protein levels were found in the hippocampus and the amygdala. Conclusions: complex alteration of several metabolic pathways occurs in the LC accompanying NFT formation at early and middle asymptomatic stages of NFT pathology. Dopaminergic/noradrenergic denervation and increased expression of α2A adrenergic receptor in the hippocampus and amygdala occur at first stage of NFT pathology, suggesting compensatory activation in the face of decreased adrenergic input occurring before clinical evidence of cognitive impairment and depression
VariaciĂłn morfolĂłgica de tres especies de curubas (Passiflora tripartita var. mollissima, P. tarminiana y P. mixta) y sus hĂbridos en el Valle del Cauca (Colombia)
Food insecurity, internalized stigma, and depressive symptoms among women living with HIV in the United States
Food insecurity, internalized HIV stigma, and depressive symptoms are independently associated with poor HIV outcomes. Food insecurity, stigma, and depression may be interrelated among women living with HIV (WLHIV). We hypothesized that food insecurity would be independently associated with internalized stigma and depressive symptoms among WLHIV in the United States (US), and would partially account for associations between stigma and depressive symptoms. We tested hypotheses using regression models and partial correlation analysis with cross-sectional data among 1317 WLHIV from the Womenâs Interagency HIV Study. In adjusted models, greater food insecurity was associated with internalized HIV stigma and depressive symptoms (all p < 0.05), exhibiting dose-response relationships. Food insecurity accounted for 23.2% of the total shared variance between depressive symptoms and internalized stigma. Food insecurity is associated with depressive symptoms and internalized HIV stigma among US WLHIV, and may play a role in the negative cycle of depression and internalized stigma
Efeitos da nutrição mineral sobre o crescimento, aspecto, composição elementar e fixação de nitrogĂȘnio em Azolla
The mineral nutrition of Azolla feliculoides Lam was studied in solutions deficient in phosphorus, potassium, calcium, magnesium, sulfur, iron and molybdenum, and in excess of Mn and Al. Dry weight, N2 fixation and mineral composition of Azolla were determined after 3 weeks. Phosphorus, potassium, calcium and magnesium deficiencies and excess of manganese and aluminium decressed growth severely and also depressed the activity of nitrogenase. Phosphorus deficiency improved the uptake of iron and zinc. Potassium deficiency increased the levels of phosphorus in dry matter. Magnesium deficiency caused lower uptake of K and better uptake of Ca, Fe and Mn. Sulfur deficiency reduced aluminium uptake and promoted the best growth. Positive correlations were found between: N content and dry matter, nitrogenase activity and N content.Azolla filiculoides Lam foi cultivado em solução nutritiva arejada, sempre desprovida de N combinado, sendo submetida aos seguintes tratamentos: omissĂŁo de P, K, Ca, Mg, S, Fe e Mo, excesso de Mn e Al. As plantas foram colhidas depois de 3 semanas da inoculação. Verificou-se que as deficiĂȘncias de P, K, Ca e Mg provocaram diminuição na produção de matĂ©ria seca e na atividade de nitrogenase. A anĂĄlise mineral mostrou que: a falta de um elemento provoca redução no seu teor; grande acumulo de Mo; diminuição no teor de Al (do inĂłculo ou contaminação) no tratamento menos S que garantiu o maior crescimento; efeitos inibitĂłrios ou sinergĂsticos semelhantes aos descritos no caso de plantas superiores. A toxidez de Al e Mn causou, principalmente a primeira, redução no crescimento e na atividade da nitrogenase. Houve correlaçÔes positivas entre: N total e crescimento, atividade de nitrogenase e N total
Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory
Data from the Pierre Auger Observatory are analyzed to search for
anisotropies near the direction of the Galactic Centre at EeV energies. The
exposure of the surface array in this part of the sky is already significantly
larger than that of the fore-runner experiments. Our results do not support
previous findings of localized excesses in the AGASA and SUGAR data. We set an
upper bound on a point-like flux of cosmic rays arriving from the Galactic
Centre which excludes several scenarios predicting sources of EeV neutrons from
Sagittarius . Also the events detected simultaneously by the surface and
fluorescence detectors (the `hybrid' data set), which have better pointing
accuracy but are less numerous than those of the surface array alone, do not
show any significant localized excess from this direction.Comment: Matches published versio
Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum
We report a first measurement for ultra-high energy cosmic rays of the
correlation between the depth of shower maximum and the signal in the water
Cherenkov stations of air-showers registered simultaneously by the fluorescence
and the surface detectors of the Pierre Auger Observatory. Such a correlation
measurement is a unique feature of a hybrid air-shower observatory with
sensitivity to both the electromagnetic and muonic components. It allows an
accurate determination of the spread of primary masses in the cosmic-ray flux.
Up till now, constraints on the spread of primary masses have been dominated by
systematic uncertainties. The present correlation measurement is not affected
by systematics in the measurement of the depth of shower maximum or the signal
in the water Cherenkov stations. The analysis relies on general characteristics
of air showers and is thus robust also with respect to uncertainties in
hadronic event generators. The observed correlation in the energy range around
the `ankle' at differs significantly from
expectations for pure primary cosmic-ray compositions. A light composition made
up of proton and helium only is equally inconsistent with observations. The
data are explained well by a mixed composition including nuclei with mass . Scenarios such as the proton dip model, with almost pure compositions, are
thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray
flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report
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