143 research outputs found
Seasonal variation of water uptake of a Quercus suber tree in Central Portugal
Hydraulic redistribution (HR) is the phenomenon
where plant roots transfer water between
soil horizons of different water potential. When dry
soil is a stronger sink for water loss from the plant
than transpiration, water absorbed by roots in wetter
soil horizons is transferred toward, and exuded into
dry soil via flow reversals through the roots. Reverse
flow is a good marker of HR and can serve as a useful
tool to study it over the long-term. Seasonal variation
of water uptake of a Quercus suber tree was studied
from late winter through autumn 2003 at Rio Frio
near Lisbon, Portugal. Sap flow was measured in five
small shallow roots (diameter of 3–4 cm), 1 to 2 m
from the tree trunk and in four azimuths and at
different xylem depths at the trunk base, using the
heat field deformation method (HFD). The pattern of
sap flow differed among lateral roots as soil dried with constant positive flow in three roots and reverse
flow in two other roots during the night when
transpiration ceased. Rain modified the pattern of
flow in these two roots by eliminating reverse flow
and substantially increasing water uptake for transpiration
during the day. The increase in water uptake in
three other roots following rain was not so substantial.
In addition, the flux in individual roots was correlated
to different degrees with the flux at different radial
depths and azimuthal directions in trunk xylem. The
flow in outer trunk xylem seemed to be mostly
consistent with water movement from surface soil
horizons, whereas deep roots seemed to supply water
to the whole cross-section of sapwood. When water
flow substantially decreased in shallow lateral roots
and the outer stem xylem during drought, water flow
in the inner sapwood was maintained, presumably due
to its direct connection to deep roots. Results also
suggest the importance of the sap flow sensor
placement, in relation to sinker roots, as to whether
lateral roots might be found to exhibit reverse flow
during drought. This study is consistent with the
dimorphic rooting habit of Quercus suber trees in
which deep roots access groundwater to supply
superficial roots and the whole tree, when shallow
soil layers were dry
Impact of primary and secondary machinery tracks on fine root growth of sugar maple after selection cutting
Selection cutting, where approximately 30% of the trees are removed every 30 years, is the main silvicultural treatment used in temperate deciduous forests of Quebec (Canada). Concerns have been raised that the use of heavy machinery is creating soil disturbances that are negatively affecting the growth and survival of remaining trees. The aim of the study was to determine if heavy machinery is affecting the growth, morphology, and architecture of sugar maple (Acer saccharum Marsh.) fine roots in and around machinery tracks left after selection logging. The study site, a sugar maple dominated stand, was located in southern Quebec. Root ingrowth bags and standard root cores were used to compare fine root growth, morphology, and architecture in and around machinery tracks one year after logging. Fine root growth of maple was reduced fivefold in both primary (multiple trip) and secondary (only one trip) machinery tracks compared with the control. There was a nonstatistical reduction in fine root growth within 1 m of the tracks. Because machinery tracks cover between 15% and 25% of a stand after selection logging, such reduction in fine root growth could be significant for the growth and survival of the remaining mature maple trees
Pleiotropic effects of erythropoietin. Influence of erythropoietin on processes of mesenchymal stem cells differentiation
The article notes that рuman recombinant erythropoietin is characterised as a factor which stimulates differentiation and proliferation of erythroid precursor cells, and as a tissue protective factor. Erythropoietin is one of the most perspective humoral agents which are involved in the preconditioning phenomeno
Electrochemical in situ studies of solar mediated oxygen transport and turnover dynamics in a tree trunk of Tilia cordata
Pharmacological modulation of cell functional activity with valproic acid and erythropoietin
Valproic acid (VA) is carboxylic acid with a branched chain, which is used as an antiepileptic drug. VA, which is an antiepileptic drug, is also a teratogen, which causes defects of a neural tube and an axial skeleton, although the mechanisms are not yet fully clear. It is shown that valproic acid reduces the intracellular level of oxygen active form
МЕТОДИКА ОЦЕНКИ СБАЛАНСИРОВАННОСТИ РЕГИОНАЛЬНОГО ПРОДОВОЛЬСТВЕННОГО РЫНКА
Author’s approach is proposed to forecast averaged per capita production and solvent demand for primary food stuffs. The approach provides balanced regional food market, selects adequate models to forecast demand and supply of the food stuffs in Novosibirsk region for the period 2013–2015. The paper interpretes the balance of regional food market as equilibrium relationship between the production volume of primary food stuffs and solvent demand of the population for those. To provide the balance of demand and supply in the long-term period forecasting of production for primary food stuffs and solvent demand expected are to be implemented. Equilibration suggests establishing the balance by importing the lacking volume of the stuffs concerned to meet the solvent demand already existing as well as by exporting excessive stuffs, the demand for is less that the production volume, beyond the regional territory. When realizing the author’s approach, regression models are used which reliability levels are high.Предложен авторский подход к прогнозированию среднедушевого производства и платежеспособного спроса на основные продовольственные товары, обеспечивающий сбалансированность регионального продовольственного рынка, подобраны адекватные модели прогнозирования спроса, определен баланс спроса и предложения этих товаров в Новосибирской области на период 2013–2015 гг. Под сбалансированностью регионального продовольственного рынка в данной работе понимается равновесное соотношение между объемом производства основных продовольственных товаров и платежеспособным спросом населения на них. Чтобы обеспечить сбалансированность предложения и спроса на товары в перспективном периоде, следует осуществить прогноз производства основных продовольственных товаров и ожидаемого платежеспособного спроса. Сбалансированность предполагает установление равновесия путем ввоза недостающего объема рассматриваемых товаров для удовлетворения уже сформированного платежеспособного спроса, а также вывоза за территорию региона излишков товаров, объем производства которых превышает спрос. При реализации авторского подхода применяются регрессионные модели, обладающие высокими уровнями надежности
Wladimir S. Woytinsky and Public Works in Saint Petersburg in 1906–1908: To the Problem of Studying the National Experience of Fight Unemployment
The article is devoted to as relevant as ever today the problem of unemployment and explores a little-known national experience of solving problems of employment in St. Petersburg in the early XX century associated with activity of the famous social Democrat and economist W. S. Woytinsky. The reaction of the government and society to the problem of unemployment is studied. There are noted the first experience of registering the unemployed in the history of Russia, and there are shown the unique nature of the first Public Works for the unemployed in Russia and the largest in Europe at that time, organized jointly by the workers ' organization — the St. Petersburg Council of the Unemployed — and the St. Petersburg City Duma. There are noted negative impact of unemployment on the general situation in the capital during the First Russian revolution, as well as on the condition of the personality of factory worker. The research perspective of the problems raised in the article is outlined
Correlation between gender dimorphism of bran, cognitive functions and level of steroid hormones in period of climacteric
Authors studied the cognitive functions and the expression of bran atrophy in 101 patients with different levels of sex hormones in climacteric. Two groups were formed. The first group was of men and women with low level of sex hormones and the second group men and women with normal levels of sex hormones. Was fixed the gender-associated differences in cognitive performance and the changes the brain, more pronounced in men and women of the first group and in men than in women.Проведено исследование показателей когнитивных функций и степени атрофии головного мозга у 101 пациента с различным уровнем содержания половых гормонов в климактерическом периоде. Выделены I группа мужчин и женщин с низким содержанием половых стероидов и II группа мужчин и женщин с нормальным количеством половых гормонов. Выявлены половые различия в показателях когнитивных функций и изменение структуры головного мозга, более выраженные у мужчин и женщин I группы с преобладанием у мужчин
Atmospheric drivers of storage water use in Scots pine
International audienceIn this study we determined the microclimatic drivers of storage water use in Scots pine (Pinus sylvestris L.) growing in a temperate climate. The storage water use was modeled using the ANAFORE model, integrating a dynamic water flow and ? storage model with a process-based transpiration model. The model was calibrated and validated with sap flow measurements for the growing season of 2000 (26 May?18 October). Because there was no severe soil drought during the study period, we were able to study atmospheric effects. Incoming radiation was the main driver of storage water use. The general trends of sap flow and storage water use are similar, and follow more or less the pattern of incoming radiation. Nevertheless, considerable differences in the day-to-day pattern of sap flow and storage water use were observed, mainly driven by vapour pressure deficit (VPD). During dry atmospheric conditions (high VPD) storage water use was reduced. This reduction was disproportionally higher than the reduction in measured sap flow. Our results suggest that the trees did not rely more on storage water during periods of atmospheric drought, without severe soil drought. A third important factor was the tree water deficit. When storage compartments were depleted beyond a threshold, storage water use was limited due to the low water potential in the storage compartments. The maximum relative contribution of storage water to daily transpiration was also constrained by an increasing tree water deficit
Effect of multipotent mesenchymal stromal cells secretome on imiquimod-induced psoriasis in rats
Multipotent mesenchymal stromal cells secretome contains a range of anti-inflammatory factors and can be used for the treatment of psoriasi
- …