Effect of Elastic Network of Ceramic Fillers on Thermal Cycle Stability of a Solid Oxide Fuel Cell Stack

Glass‐based seals for planar solid‐oxide fuel‐cell (SOFC) stacks are open to uncontrolled deformation and mechanical damages, limiting both sealing integrity and stack reliability, particularly in thermal cycle operations. If the glass‐based seals work like an elastomer‐based compressive seal, SOFC stacks may survive unprecedented numbers of thermal cycles. A novel composite sealing gasket is successfully developed to mimic the unique features of the elastomer‐based compressive seal by controlling the composition and packing behavior of binary ceramic fillers. A single‐cell SOFC stack undergoes more than 100 thermal cycles with little performance loss, during which the sealing integrity is lost/recovered repeatedly upon cooling and reheating, corresponding to unloading/loading of the elastomer‐based compressive seal. The thermal‐cycle responses of the SOFC stack are explained in sequence by the concurrent events of elastic deformation/recovery of ceramic filler network and corresponding redistribution of sealing glass.     

Early grey crescent formation experimentally induced by cycloheximide in the axolotl oocyte

Summary The effects of cycloheximide (CH) on grey crescent formation in artificially maturedAmbystoma mexicanum oocytes were determined. CH induced grey crescent formation after a few hours, especially after a 45° to 90° rotation from the vertical animal-vegetal axis. With low concentrations of CH (about 0.5 ng/oocyte), meiosis was still able to proceed normally to the stable second metaphase stage, but higher concentrations blocked it after 1st polar body extrusion and an interphasic nucleus appeared. Such effects were compared to those of inactone, an analogue of cycloheximide, which as a pure substance does not inhibit protein synthesis, but still contained a small amount of CH in the available samples. It is concluded that grey crescent formation can occur in non-activated oocytes. The effects of cycloheximide might be due to partial inhibition of protein synthesis and the presence of a proteinic inhibitor of the symmetry reaction in the normal oocyte is suggested.     

Structural and possible thermoregulatory differences in the ears of grey kangaroos

1. 1. Western Grey Kangaroos generally inhabit more arid and hotter regions than Eastern Greys.

2. 2. Ears from Western Greys are significantly thinner, less furred and have smaller, thinner hairs than those from Eastern Grays.

3. 3. Ears may act as better heat dissipators in the Western Greys than in the Eastern Greys.

Weddell seals do not lengthen calls in response to conspecific masking

Some mammalian and avian species alter their vocal communication signals to reduce masking by background noises (including conspecific calls). A preliminary study suggested that Weddell seals (Leptonychotes weddellii) increase the durations of some underwater call types when overlapped by another calling seal. The present study examined the durations and overlapping sequences of Weddell seal calls recorded in Eastern Antarctica. The calling rate, call type (13 major categories), total duration, numbers of elements per call and overlapping order of 100–200 consecutive calls per recording location were measured. In response to increased conspecific calling rates, the call durations and numbers of elements (within repeated-element call types) did not change or became shorter. Calls that were not overlapped were 3.8?±?6.1 s long, the first call in a series of overlapped calls was 14.4?±?15.7 s and subsequent calls in an overlapping series were 6.5?±?10.3 s. The mean durations of non-overlapped and overlapped calls matched random distributions. Weddell seals do not appear to be adjusting the durations or timing of their calls to purposefully avoid masking each other’s calls. The longer a call is, the more likely it is to overlap another call by chance. An implication of this is that Weddell seals may not have the behavioural flexibility to reduce masking by altering the temporal aspects of their calls or calling behaviours as background noises (natural and from shipping) increase.     

Antagonistic Properties of Two Bacterial Biocontrol Agents of Grey Mould Disease

Bacillus pumilus NCIMB 13374 and Pseudomonas fluorescens NCIMB 13373 inhibit the growth of Botrytis cinerea , the cause of grey mould of strawberries. Both antagonists increased the pH of the growth medium from pH 6 to pH 8-8.5 and both produced antifungal agents. The compound(s) produced by B. pumilus had a fungicidal effect during conidial germination, whereas the compound(s) produced by P. fluorescens had a fungistatic effect. There was no evidence for the production of inhibitory volatile compounds. Both isolates also showed the ability to inhibit other strawberry fungal pathogens, and have potential for a wider range of biocontrol of plant diseases.     

大中微量元素组合对水稻产量和品质影响的灰色综合评判

本文运用灰色系统理论，探讨了大中微量元素组合对水稻产量和品质的影响，并对其进行了灰色关联评判，结果表明复4S1Fe1Cu1和复2S2Fe1Cu2两个组合，对水稻产量和品质影响最为明显，并与田间试验情况一致。     

DENSITY DEPENDENCE IN NORTHERN FUR SEALS (CALLORHINUS URSINUS)

This paper summarizes, updates, and interprets information on density-dependent dynamics of populations of the northern fur seal ( Callorhinus ursinus ). Density-dependent changes observed in these populations have involved various aspects of growth (body length, body weight, tooth weight, and size of other skeletal parts, especially the skull), survival, age at maturation, incidence of disease, and time spent foraging. For the population of northern fur seals on St. Paul Island of the Pribilof Islands, which was observed during a major increase and during two significant declines, density-dependent changes that occurred during the growth of the population were reversed during the declines. The Robben Island population in the western Pacific declined after 1965, and the decline was accompanied by changes similar to those observed during the declines on the Pribilof Islands. Although data are not available for all age and sex classes, it appears that most or all components of the populations exhibit similar changes. The overall implication of these changes is that current populations on Robben Island and the Pribilof Islands are reduced to levels below what could be supported by the resources available in their environments. Density dependence for this species is consistent with that of other large mammals, specifically in that vital rates for fur seals ate related to density in a nonlinear fashion.