221 research outputs found
Plant Root Mass Fraction Response to Soil Resource Limitation in the Context of Dry Mediterranean Rangeland
Root mass fraction (RMF) was proposed as a stable measurement of plant resource partitioning that can represent plant acquisition–conservation trade‐offs. We examined the effects of soil resources availability on RMF of abundant annual plant species of water-limited rangeland. We used data from controlled experiments in which nine species were grown under variable water and nitrogen availabilities and their root and shoot biomass were examined at flowering time. In legumes we examined also presence of N2-fixation. In all of the species, reduced water and/or nitrogen availability was associated with increased RMF. However, the magnitude of variation in RMF found between the resource availability treatments was different among the annual species. At the intra-specific level, plant size was negatively related to RMF. Finally, in legumes RMF corresponded to the species’ N2-fixation status
Projection of two biphoton qutrits onto a maximally entangled state
Bell state measurements, in which two quantum bits are projected onto a
maximally entangled state, are an essential component of quantum information
science. We propose and experimentally demonstrate the projection of two
quantum systems with three states (qutrits) onto a generalized maximally
entangled state. Each qutrit is represented by the polarization of a pair of
indistinguishable photons - a biphoton. The projection is a joint measurement
on both biphotons using standard linear optics elements. This demonstration
enables the realization of quantum information protocols with qutrits, such as
teleportation and entanglement swapping.Comment: 4 pages, 3 figures, published versio
The influence of defoliation and nitrogen on the regrowth of Rhodes grass (Chloris gayana Kunth). 2. Etiolated growth and non-structural carbohydrate, total-N and nitrate-N content.
Data are given on the chemical composition of Rhodes grass cv. Common grown in a heated glasshouse [see HbA 42, 1910]. Plants given high N (8.29 meq/100 g soil) contained about 30% less carbohydrate in the stubble and roots than those given low N (1.43 meq/100g). The carbohydrate content of plants cut every 28 days was generally lower than that of plants cut every 14 days. Amounts of etiolated growth in darkness after cutting were positively correlated with the carbohydrate level in the roots and in the stubble. The percentage of tillers exhibiting regrowth in darkness increased linearly up to about 60% with increase in the amount of etiolated growth. Contents of total N in roots and in stubble were almost double at the high rate of N. Amounts of nitrate as a proportion of total N were about 12% in low-N plants and up to 47% in high-N plants. The nitrate contents of shoots, stubble and roots were negatively correlated with the carbohydrate levels in each of these tissues. The overall difference in carbohydrate level between shoots, stubble and roots was relatively small. It was concluded that Rhodes grass had a limited capacity to accumulate reserve material when grown under conditions favouring rapid growth. (Abstract retrieved from CAB Abstracts by CABI’s permission
The influence of defoliation and nitrogen on the regrowth of Rhodes grass (Chloris gayana Kunth). 1. Dry matter production and tillering.
In pot experiments Rhodes grass (cv. "Common" and "Katambora") was fertilized with 1.43 and 8.29 meq N/100 g soil over a period of 56 days and was cut every 14 or 28 days. Cutting at 28 days considerably increased total shoot weight. Root weight per pot of low-N plants was 31 and 23% higher than that of high-N plants at 14- and 28-day cutting intervals, respectively. N application generally increased the average number of harvest tillers, but individual tillers regrew a fewer number of times than those receiving low N. (Abstract retrieved from CAB Abstracts by CABI’s permission
Regrowth potential of shoot and of roots of Rhodes grass (Chloris gayana Kunth) after defoliation.
In field and pot trials the effect of different lengths of pre-cutting periods and of cutting intervals on regrowth of shoot and of root were studied in Rhodes grass cv. Katambora. The initial regrowth of the sward after a long (28 days) pre-cutting period was slower than after a short (7 days) pre-cutting period. The reduction of the residual LAI following the extension of the pre-cutting period was associated with reduction in the number of tillers capable of regrowth after defoliation. Root wt. decreased drastically following cutting when the initial root wt. was high (long pre-cutting period), but little when the initial root wt. was small (short pre-cutting period). The decrease in root wt. lasted c. 1 wk after which it increased at a more or less constant rate proportional to the increase of shoot wt. irrespective of the length of the pre-cutting period. The lack of the capability of tillers to regrow after cutting was closely related with developmental stage of tillers. Since tillers of subtropical and tropical grasses have a tendency for early stem elongation, it was concluded that the relatively small number of sites available for regrowth in these grasses is the major deterrent for quick shoot growth of the sward after defoliation. (Abstract retrieved from CAB Abstracts by CABI’s permission
Value of Assistance for Grasping
In many realistic settings, a robot is tasked with grasping an object without
knowing its exact pose. Instead, the robot relies on a probabilistic estimation
of the pose to decide how to attempt the grasp. We offer a novel Value of
Assistance (VOA) measure for assessing the expected effect a specific
observation will have on the robot's ability to successfully complete the
grasp. Thus, VOA supports the decision of which sensing action would be most
beneficial to the grasping task. We evaluate our suggested measures in both
simulated and real-world robotic settings
Effects of electromagnetic radiation on intact bovine lens epithelium in culture conditions
Цель: исследовать влияние неионзирующего электромагнитного излучения на хрусталик глаза, с использованием культуры ткани хрусталика глаза.
Методы: Хрусталики бычьего глаза были культивированы в течение 10 дней. Изучено 59 хрусталиков. Обработанные хрусталики были облучены 1.1 GHz, 2.22mW в течение 192 циклов по 50 минут с паузой 10 минут. Затем в контрольных и обработанных культуральных клетках хрусталика определяли активность ферментов.
Результаты: Экспозиция 2.22mW и 1.1GHz повредила хрусталик глаза. Лучевое повреждение проявилось в эпителиальном слое хрусталика глаза, и сопровождалось изменениями активности эпителиальных ферментов.
Выводы: Электромагнитное излучение имеет выраженное воздействие на хрусталик глаза Экспозиция описанными выше уровнями удельной энергии воздействует на эпителий хрусталика глаза, что выражается в изменении активности эпителиальных ферментов.Purpose: To investigate the effects of nonionizing electromagnetic radiation on the eye lens using a lens organ culture system.
Methods: Bovine lenses were incubated in organ culture conditions for 10 days. 59 lenses were used in this study. Treated lenses were exposed to 1.1GHz, 2.22mW for 192 cycles of 50 minutes irradiation followed by 10 minutes pause. At the end of the culture period control and treated lenses were taken for enzyme analysis.
Results: Exposure to 2.22mW at 1.1GHz caused damage to the lens. The radiation damage appeared at the lens epithelial layer accompanied by activity changes of lens epithelial enzymes.
Conclusions: Electromagnetic radiation has a clear impact on the eye lens. Exposure above specific energy levels affects lens epithelium as demonstrated by changes in epithelial enzyme activities
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