The cytochemical localization of ascorbic acid in root tip cells

The intracellular distribution of ascorbic acid was studied in frozen-dried root tips of Allium cepa and Vicia faba by the silver nitrate procedure. The sites of the ascorbic acid as indicated by the deposited silver appear as spherical (0.2 to 0.6 µ in diameter) cytoplasmic particles. The site appears to have small amounts of lipides and to be rich in ribonucleic acid. These particles are concluded to be submicroscopic in size and associated, in the elongating cell, with the cell surface. In the meristematic cells they appear fewer in number and are distributed throughout the cytoplasm

Quantifying the onset of the concentric phase of the force–time record during jumping

Thirteen college students performed a drop jump from height equal to their peak vertical jump, single leg jumps from the left and right legs, and a counter movement jump. Vertical ground reaction force (GRF) obtained via an AMTI force plate and video analysis of markers placed on the hip, knee, lateral malleolus, and fifth metatarsal were used to estimate reaction forces on the knee joint. One-way Repeated Measures ANOVA indicated no differences for knee joint reaction forces relative to body weight or peak GRF for any of the jumps (p \u3e 0.05). Average measures Intraclass Correlation Coefficients ranged from r = 0.90 to 0.97. Results indicate that peak GRF and knee joint reaction forces during the drop jump, counter movement jump, and single leg left and right leg jumps are reliable measures

Rent Seeking and the Common Agricultural Policy: Do member countries free ride on lobbying?

The Common Agricultural Policy is modelled as a club good providing the European Union (EU) farmer with financial benefits. We build an economic model which explains how much farmers in individual EU countries invest in rent-seeking activities in order to test for free-riding behaviour on lobbying costs. For our investigation we group the EU member countries by farm structure, and the type of benefit received. We explain the fees paid by farmers for lobbying by other countries fees, political variables, and country and regional agricultural characteristics. The model shows that some member countries free ride on others. This suggests a form of policy path dependency and leads to a suboptimal investment on lobbying of 7.5%.free-riding, rent-seeking, Common Agricultural Policy, Agricultural and Food Policy, International Relations/Trade, Political Economy, D72, Q18,

RENT SEEKING AND THE COMMON AGRICULTURAL POLICY: DO MEMBER COUNTRIES FREE RIDE ON LOBBYING?

The Common Agricultural Policy is modelled as a club good providing the European Union (EU) farmer with financial benefits. We build an economic model which explains how much farmers in individual EU countries invest in rent-seeking activities in order to test for free-riding behaviour on lobbying costs. For our investigation we group the EU member countries by farm structure, and the type of benefit received. We explain the fees paid by farmers for lobbying by other countries fees, political variables, and country and regional agricultural characteristics. The model shows that some member countries free ride on others. This suggests a form of policy path dependency and leads to a suboptimal investment on lobbying of 7.5%.Free-riding, rent-seeking, Common Agricultural Policy, Agricultural and Food Policy, Institutional and Behavioral Economics,

Faster than the blink of an eye

Arboreal snakes such as the amazon tree boa (Corallus hortulanus) are able to cantilever large sections of their body for very long periods of time with seemingly minimal muscular effort. From this cantilevered position they exert quick strikes as well as compensate for any movement of the object from which they cantilever. The mechanisms of muscle coordination required for the dynamic switch between resting and strike have been hypothesized for terrestrial puff adders (Bitis arietans) to result from the vast and unique musculo-tendon arrangement of the snake's epaxial muscles put under pre-strike tension, i.e. a spring-like mechanism where the snake is able to store a large amount of energy in tendons which can then be later quickly released. Furthermore, while muscle activity during gap crossing or extension activities has been described for an arboreal species, it is not clear how the stationary snake's muscles compensate for perturbations of the anchoring object, e.g. as happens in the wild with a branch swaying in the breeze. Using a self-built high-speed 3D tracking system along with a novel method for collecting chronic multi-electrode bipolar electromyography (EMG) information, my data is not only unsupportive of the elastic energy-storing strike hypothesis but provides insights to the muscle coordination required for stabilization in a moving, as well as stationary, environment