Experimental spin ratchet

Spintronics relies on the ability to transport and use the spin properties of an electron rather than its charge. We describe a spin ratchet at the single-electron level that produces spin currents with no net bias or charge transport. Our device is based on the ground-state energetics of a single-electron transistor comprising a superconducting island connected to normal leads via tunnel barriers with different resistances that break spatial symmetry. We demonstrate spin transport and quantify the spin ratchet efficiency by using ferromagnetic leads with known spin polarization. Our results are modeled theoretically and provide a robust route to the generation and manipulation of pure spin currents.     

Assessment of quality characteristics of new Vitis vinifera L. cultivars for temperate climate vineyards

Since quality requirements for table grapes are mainly related to their physico-chemical and mechanical features, the aim of this work was to provide useful data for grape producers and consumers concerning the quality characteristics of table grapes of five new Vitis vinifera L. cultivars created in Romania and tending to spread within the temperate climate vineyards. During grape maturation, sugar content increased in a lesser extent than the reducing of total acidity, a balanced taste of grapes was given by the decrease in total acidity rather than sugar accumulation. Grapes of analysed cultivars showed lower concentrations of ascorbic acid and a higher content of organic nitrogenous compound. Berries with higher weight and volume (Transilvania cv.) incurred a higher mechanical deformation, while long berries (Gelu cv.) showed higher resistance to detachment from the pedicel, indicating higher resistance of grapes to packing, transport and storage. Antioxidant activity of mature grapes was high, but involvement of nonflavonoids in increasing the antioxidant capacity was statistically non-significant. Seeded table grapes of new Vitis vinifera L. cultivars showed superior physico-chemical and mechanical characteristics, indicating their high quality in the conditions of temperate continental climate, and promoting the studied cultivars as important grapevine germplasm resources.     

Seasonal variation in growth,consumption and growth efficiency in overwintering juvenile steelhead

Food availability and thermal regimes can largely govern growth opportunities in fishes. In temperate regions, streams can exhibit summer temperatures that exceed the optima for coolwater-adapted species relative to the amount of available food, and therefore, spring and fall may confer better growing conditions, especially for larger size classes. We examined the relationship between growth, consumption and growth efficiency across seasons in juvenile steelhead (Oncorhynchus mykiss) in their natal streams in Idaho, USA. Subyearling (0+) growth rates were higher in summer, whereas yearlings exhibited no statistically significant difference in growth between seasons. Consumption rates were overall lower in winter–spring but constituted a higher proportion of maximum consumption compared with summer and fall, indicating better food availability relative to metabolic demands. Net growth efficiencies were higher in winter–spring, but substantially more so than the proportion of maximum consumption. This suggests that overwinter growth performance was driven at least partly by higher growth efficiency, and the effect was most pronounced for yearling steelhead. The low proportions of maximum consumption for both age classes suggest that food was an overall limiting factor to growth, especially in summer when metabolic demands were highest. We discuss how temperature-based models can overestimate growth in the warmest parts of the year and develop a simple conceptual model for the seasonal timing of juvenile growth. In anadromous populations, the outmigration of presmolts in spring can reduce the level of competition. For the individuals that remain in the river, growth in this period can be particularly important.     

Sex-specific connectivity modelling for brown bear conservation in the Carpathian Mountains

Landscape Ecology - Romania is currently one of the best-connected landscapes, with high-quality habitats and a high density of brown bears. However, regional development measures are needed for...     

Needs of private forest owners in the context of changing political systems: Lithuania as a case study

During the first half of the 20^th century the Baltic States were independent democratic nations where private forest ownership was practiced. After annexation to the Soviet Union, individuals in the Baltic States lost their ownership rights and collective ownership was introduced. Currently, after the break-up of the Soviet Union, the land restitution process in the forest sector is coming to an end and the ownership pattern as well as tenure rights are settled. A survey was undertaken to investigate the current state of the private forest sector in general, and the needs and expectations of private forest owners (PFO). Results of the study indicated that for private forest owners their forests first of all provide aesthetic and environmental protection values. Lithuanian PFOs lack information of forests and forest management, face extensive bureaucracy and need help in protecting their forests from fires, diseases and timber thieves.     

带冷却段的中密度纤维板连续压机

连续压机的一个主要优点是，板坯通过压机时，压机不同位置上的压力和温度都可以调整。采用带冷却段的库斯特连续压机生产ＭＤＦ的经验表明：将压机最后一段的温度降至１００℃以下是连续压机的又一大革新，具有很大的优越性。２０世纪７０年代初期，一家丹麦工厂首先揭示了在人造板生产中采用具有冷却功能的压机的优点：将温度快速冷却至７０℃以下降低了豚醛树脂的水解，减少了毛板的挠曲和厚度偏差，从而可减小板子的砂光余量。这一发现得到了另一试验报告的支持。该试验采用具有冷却功能的单层压机，其目的是减少毛板的冷却时间和后固化…     

Accurate single-tree positions from a harvester: a test of two global satellite-based positioning systems

Accurate positioning of single trees registered automatically during harvesting operations opens up new possibilities for reducing the field sampling effort in forest inventories utilising remotely sensed data. In the present study, we propose to use a harvester to collect single-tree data during regular harvest operations and use these data to substitute or supplement traditional measurements on sample plots. Today’s harvesters are capable of recording single-tree information such as species and diameter at breast height, and a cut-to-length harvester was equipped with an integrated accurate positioning system based on real-time kinematic global satellite positioning, as well as a low-cost global navigation satellite system (GNSS) receiver mounted directly on the harvester head. Positions from 73 trees were evaluated and compared to coordinates obtained using a total station. At the single-tree level, the mean error for the integrated positioning system was 0.94?m. The low-cost GNSS receiver mounted on the harvester head yielded a mean error of 7.00?m. The sub-meter accuracy obtained with the integrated system suggests that data acquired with a harvester using this positioning system may have a great potential as a method for single-tree field data acquisition.