Volcanic activity and global change: probable short-term and possible long-term linkages

Article reviews annual to decadal climate response to volcanism; long-term climatic response to volcanism; and recent results from ocean drilling in the North Pacific.

Low short term timing jitter in an integrated monolithic extended cavity semiconductor mode-locked laser

Jitter measurements were performed on a monolithically integrated active/passive cavity multiple quantum well laser, actively mode-locked at 10 GHz via modulation of an absorber section. Sub-10 ps pulses were produced upon optimization of the drive conditions to the gain, distributed Bragg reflector, and absorber sections. A model was also developed using travelling wave rate equations. Simulation results suggest that spontaneous emission is the dominant cause of jitter, with carrier dynamics having a time constant of the order of 1 ns.

Short-term preservation of Brachionus calyciflorus: effects of storage on protein, lipid and carbohydrate contents

The short-term preservation of Brachionus calyciflorus for 45 days at three different temperatures (4, -4 and -20°C) led to decrease in protein, lipid and carbohydrate contents in all the three cases. However, the rate of deterioration was much higher at 4C than at -4 and -20°C. At 4C, protein, lipid and carbohydrate contents reduced by 76.78, 81.11 and 62.83%, respectively, and at -4°C, these were 27.94, 37.46 and 18.42%, respectively, whereas at -20°C, the deterioration was limited to 9.28, 16.44 and 11.35%, respectively, when compared with the control values. Thus, preservation at -20°C is comparatively better as it exerts limited effect on the protein, lipid and carbohydrate contents of B. calycijlorus.

A STUDY ON THE EFFECT OF LESIONS OF AREA-7 OF THE PARIETAL CORTEX ON THE SHORT-TERM VISUAL SPATIAL MEMORY OF RHESUS-MONKEYS (MACACA-MULATTA)

This research is focused on the contribution of area 7 to the short-term visual spatial memory. Three rhesus monkeys (Macaca mulatta) were trained in the direct delayed response task in which 5 delay intervals were used in each session. When each monkey reached the criterion of 90% correct responses in 5 successive sessions, two monkeys underwent a surgery while the other one received a sham operation as a control. In the first stage of the surgery, bilateral areas 7a, 7b and 7ip of the parietal cortex of two monkeys were precisely lesioned. After 7 days of recuperation, the monkeys were required to do the same task. The average percentage of correct responses in the lesioned animals decreased from 94.7% to 89.3% and 93.3% to 82.0% respectively (no significance, P > 0.05, n = 2). In addition, the monkeys' complex movements were mildly impaired. The lesioned monkeys were found to have difficulty picking up food from the wells. In the second stage, bilateral area 7m was lesioned. In the 5 postoperative sessions, the average percentage of correct responses in one monkey, with a relatively precise 7m lesion, decreased from 94.7% to 92.2% (no significance, P > 0.05), while the other monkey, with widely spread necrosis of lateral parietal cortex, showed an. obvious decline in performance, but still over the chance level. After 240 trials this monkey reattained the normal criterion. The results of this research suggest that the lesions of area 7 of the parietal cortex did not significantly affect the short-term visual spatial memory, which has been shown to be sensitive to lesions of the prefrontal cortex; they also support the notion of dissociation of spatial functions in the prefrontal and parietal cortices.

Glycine receptor activation regulates short-term plasticity in CA1 area of hippocampal slices of rats

Functional glycine receptors (GlyRs) are enriched in the hippocampus, but their roles in synaptic transmission are unclear. In this study, we examined the effect of GlyR activation on paired-pulse stimulation of the whole-cell postsynaptic currents (PSCs)

Short-term in vitro responses of human peripheral blood monocytes to ferritic stainless steel fiber networks.

Beneficial effects on bone-implant bonding may accrue from ferromagnetic fiber networks on implants which can deform in vivo inducing controlled levels of mechanical strain directly in growing bone. This approach requires ferromagnetic fibers that can be implanted in vivo without stimulating undue inflammatory cell responses or cytotoxicity. This study examines the short-term in vitro responses, including attachment, viability, and inflammatory stimulation, of human peripheral blood monocytes to 444 ferritic stainless steel fiber networks. Two types of 444 networks, differing in fiber cross section and thus surface area, were considered alongside austenitic stainless steel fiber networks, made of 316L, a widely established implant material. Similar high percent seeding efficiencies were measured by CyQuant® on all fiber networks after 48 h of cell culture. Extensive cell attachment was confirmed by fluorescence and scanning electron microscopy, which showed round monocytes attached at various depths into the fiber networks. Medium concentrations of lactate dehydrogenase (LDH) and tumor necrosis factor alpha (TNF-α) were determined as indicators of viability and inflammatory responses, respectively. Percent LDH concentrations were similar for both 444 fiber networks at all time points, whereas significantly lower than those of 316L control networks at 24 h. All networks elicited low-level secretions of TNF-α, which were significantly lower than that of the positive control wells containing zymosan. Collectively, the results indicate that 444 networks produce comparable responses to medical implant grade 316L networks and are able to support human peripheral blood monocytes in short-term in vitro cultures without inducing significant inflammatory or cytotoxic effects.

Variability in encoding precision accounts for visual short-term memory limitations.

It is commonly believed that visual short-term memory (VSTM) consists of a fixed number of "slots" in which items can be stored. An alternative theory in which memory resource is a continuous quantity distributed over all items seems to be refuted by the appearance of guessing in human responses. Here, we introduce a model in which resource is not only continuous but also variable across items and trials, causing random fluctuations in encoding precision. We tested this model against previous models using two VSTM paradigms and two feature dimensions. Our model accurately accounts for all aspects of the data, including apparent guessing, and outperforms slot models in formal model comparison. At the neural level, variability in precision might correspond to variability in neural population gain and doubly stochastic stimulus representation. Our results suggest that VSTM resource is continuous and variable rather than discrete and fixed and might explain why subjective experience of VSTM is not all or none.

Short-term cytotoxic and inflammatory responses of human monocytes to stainless steel fibre networks

The aim of the current work was to examine the human monocyte response to 444 ferritic stainless steel fibre networks. 316L austenitic fibre networks, of the same fibre volume fraction, were used as control surfaces. Fluorescence and scanning electron microscopies suggest that the cells exhibited a good degree of attachment and penetration throughout both networks. Lactate Dehydrogenase (LDH) and TNF-α releases were used as indicators of cytotoxicity and inflammatory responses respectively. LDH release indicated similar levels of monocyte viability when in contact with the 444 and 316L fibre networks. Both networks elicited a low level secretion of TNF-α, which was significantly lower than that of the positive control wells containing zymosan. Collectively, the results suggest that 444 ferritic and 316L austenitic networks induced similar cytotoxic and inflammatory responses from human monocytes. © 2012 Materials Research Society.

Short-term effects of drawing water for connectivity of rivers and lakes on zooplankton community structure

During 28-29, September 2005, water was drawn from Hanjiang River and Houguan Lake to the Yangzi River via Sanjiao Lake and Nantaizi Lake in Wuhan in order to provide favorable conditions for ecosystem restoration. To evaluate the feasibility and validity of drawing water as a means of ecosystem restoration, zooplankton populations were studied 3 times (before, immediately after finishing and a month after drawing water) at seven locations from 27 Sept. 2005 to 2 Nov. 2005. Water quality in the lakes was mostly improved and zooplankton species richness decreased as soon as drawing water had finished but increased a month after drawing water. Zooplankton density and biomass was reduced in the lakes by drawing water but was increased at the entrance to Sanjiao Lake because of landform geometry change. Before drawing water, most species in Sanjiao Lake e.g., Brachionus sp. and Keratella sp. were tolerant of contamination. After drawing water oligotrophic-prone species such as Lecane ludwigii and Gastropus stylifer emerged. We conclude that drawing water could be important for improving water quality and favour ecosystem restoration. Dilution of nutrient concentrations may be an important role in the effect.