Size Effects in Micro-bending Deformation of MEMS Devices Based on the Discrete Dislocation Theory

In the present research, the discrete dislocation theory is used to analyze the size effect phenomena for the MEMS devices undergoing micro-bending load. A consistent result with the experimental one in literature is obtained. In order to check the effectiveness to use the discrete dislocation theory in predicting the size effect, both the basic version theory and the updated one are adopted simultaneously. The normalized stress-strain relations of the material are obtained for different plate thickness or for different obstacle density. The prediction results are compared with experimental results.

Upwind compact method and direct numerical-simulation of driven flow in a square cavity

A high-order accurate finite-difference scheme, the upwind compact method, is proposed. The 2-D unsteady incompressible Navier-Stokes equations are solved in primitive variables. The nonlinear convection terms in the governing equations are approximated by using upwind biased compact difference, and other spatial derivative terms are discretized by using the fourth-order compact difference. The upwind compact method is used to solve the driven flow in a square cavity. Solutions are obtained for Reynolds numbers as high as 10000. When Re less than or equal to 5000, the results agree well with those in literature. When Re = 7500 and Re = 10000, there is no convergence to a steady laminar solution, and the flow becomes unsteady and periodic.

THE ORIGIN AND GENETIC DIFFERENTIATION OF NATIVE BREEDS OF PIGS IN SOUTHWEST CHINA - AN APPROACH FROM MITOCHONDRIAL-DNA POLYMORPHISM

Mitochondrial DNA (mtDNA) of six breeds of native domestic pigs from Yunnan province, southwest China, and two wild boars obtained from Sichuan, China, and Vietnam was analyzed using 20 restriction endonucleases that recognize six nucleotides. Restriction maps were made by double-digestion methods and polymorphic sites were located on the map. According to their mtDNA restriction types, all the breeds were classified into six groups. Genetic distances among groups were calculated to define their phylogenetic relationships. The relationship between the Sichuan wild boar and domestic pigs is close, while the Vietnamese wild boar is relatively far from them, so the domestic pigs in southwest China are likely to have originated from a wild pig which distributed in west China. We compare our results with previous reports in literature and discuss the relationship among Chinese pigs, Japanese pigs, and European pigs. The mtDNA cleavage pattern of the Mingguang pig digested by EcoRV was identical to that of Duroc; mutations at the EcoRI site, detected in the mtDNA of two Dahe pigs, are the same as in the Vietnamese wild boar, suggesting that mutational hot spots exist in the mtDNA of pigs.

Intergroup interactions in Tibetan macaques at Mt. Emei, China

Data on intergroup-interactions (I-I) were collected in 5 seasonally provisioned groups (A, B, D, D-1, and E) of Tibetan macaques (Macaca Thibetana) at Mt. Emei in three 70-day periods between 1991 April-June (P1), September-November (P2), December-1992 February (P3). The I-I were categorized as forewarning made by high-ranking males (including Branch Shaking and/or Loud Calls), long-distance interactions in space (specified by changes in their foraging movements), and close encounters (with Affinitive Behavior, Male's Herding Female, Sexual Interaction, Severe Conflict, Adult Male-male Conflict, Opportunistic Advance and Retreat, etc. performed by different age-sex classes). From periods Fl to P3, the I-I rate decreased with reduction in population density as a positive correlate of food clumpedness or the number of potential feeders along a pedestrian trail. On the other hand, from the birth season (BS, represented by P1 and P3) to the mating season (MS, represented by P2) the dominance relation between groups, which produced a winner and a loser in the encounters, became obscure; the proportion of close encounters in the I-I increased; the asymmetry (local groups over intruders) of forewarning signals disappeared; the rate of branch shaking decreased; and sometimes intergroup cohesion appeared. Considering that sexual interactions also occurred between the encountering groups, above changes in intergroup behaviors may be explained with a model of the way in which the competition for food (exclusion) and the sexual attractiveness between opposite sexes were in a dynamic equilibrium among the groups, with the former outweighing the latter in the BS, and conversely in the MS. Females made 93% of severe conflicts, which occurred in 18% of close encounters. Groups fissioned in the recent past shared the same home range, and showed the highest hostility to each other by females. In conspicuous contrast with females' great interest in intergroup food/range competition, adult male-male conflicts that were normally without body contact occurred in 66% bf close encounters; high-ranking male herding of females, which is typical in baboons, appeared in 83% of close encounters, and showed no changes with season and sexual weight-dimorphism; peripheral juvenile and subadult males were the main performers of the affinitive behaviors, opportunistic advance and retreat, and guarding at the border. In brief, all males appeared to "sit on the fence" at the border, likely holding out hope of gaining the favor of females both within and outside the group. Thus, females and males attempted to maximize reproductive values in different ways, just as expected by Darwin-Trivers' theory of sexual selection. In addition, group fission was observed in the largest and highest-ranking group for two times (both in the MS) when its size increased to a certain level, and the mother group kept their dominant position in size and rank among the groups that might encounter, suggesting that fission takes a way of discarding the "superfluous part" in order to balance the cost of competition for food and mates within a group, and the benefit of cooperation to access the resources for animals in the mother group. (C) 1997 Wiley-Liss, Inc.

In situ studies on the bioaccumulation of microcystins in the phytoplanktivorous silver carp (Hypophthalmichthys molitrix) stocked in Lake Taihu with dense toxic Microcystis blooms

The phytoplanktivorous silver carp is an important biomanipulation fish to control cyanobacterial blooms and is also a food fish with the greatest production in China. The accumulation of the hepatotoxic microcystins (MCs) determined by LC-MS in various organs of silver carp was studied monthly in Lake Taihu dominated by toxic Microcystis aeruginosa. Average recoveries of spiked fish samples were 78% for MC-RR and 81% for MC-LR. The highest content of MCs was found in the intestine (97.48 mu g g(-1) DW), followed by liver (6.84 mu g g(-1) DW), kidney (4.8 8 mu g g(-1) DW) and blood (1.54 mu g g(-1) DW), and the annual mean MC content was in the order of intestine > liver > kidney > blood > muscle > spleen > gallbladder > gill. Silver carp could effectively ingest toxic Microcystis cells (up to 84.4% of total phytoplankton in gut contents), but showed fast growth (from 141 g to 1759 g in I year in mean weight). Silver carp accumulated less microcystins in liver than other animals in the same site or other fish from different water bodies at similar level of toxin ingestion. There was possible inhibition of the transportation of the most toxic MC-LR across the gutwall. Muscle of silver carp in Lake Taihu should not be consumed during period of dense Microcystis blooms while viscera were risky for consumption in more months. (c) 2006 Elsevier B.V. All rights reserved.

Aquatic resource conservation - The first Yangtze finless porpoise successfully born in captivity

Background. As the sole freshwater subspecies of finless porpoise (Neophocaena phocaenoides), the Yangtze finless porpoise (N. p. asiaeorientalis) lives only in the middle and lower reaches of the Yangtze River and its appended Poyang and Dongting Lakes. As a result of human activity on the river, including over and illegal fishing, pollution, transportation and dam construction, the population of Yangtze finless porpoises has been steadily and rapidly decreasing during the past several decades, which leads the animal to be endangered. Methods. For saving this unique animal from extinction, three corresponding measures, in situ conservation, ex situ conservation, and intensifying breeding research in captivity, were proposed and have been implemented since the 1980s. Results. After successfully rearing the animals in captivity for almost nine years, the first Yangtze finless porpoise was successfully born in captivity on July 5, 2005. The calf is male, with a body length of 69 cm. This is the first freshwater cetacean ever born in captivity. Conclusion. The successful birth of this calf confirms that it is possible to breed the Yangtze finless porpoise in captivity. Furthermore, this will greatly benefit the conservation efforts, and also greatly bolster our on-going efforts to study the reproductive biology of these animals. Recommendation. More studies and efforts are expected to establish a sustainable, captive colony of the Yangtze finless porpoise, which will not only greatly expand our knowledge about the reproduction biology of this animal, but also help to redeem the wild population through a careful yearly 'soft releasing' process.

Dynamic changes of total bacteria and Vibrio in an integrated seaweed-abalone culture system

Polyculture of seaweeds alongside fed animal aquaculture is an environmentally friendly means of avoiding eutrophication problem both in land-based and sea-based monoculture systems. Many aspects of such polyculture systems have been described, but little attention has been given to the impact of live seaweeds on the microbiological properties of the water that connects the algae and animals. In this investigation, the Pacific red alga Gracilaria textorii was cultured in a recirculated dual tank system (150 L) with the juvenile abalone Haliotis discus hannai. Dynamic changes of total bacteria (TB) and total Vibrio (TV) in the water of polyculture and monoculture systems were evaluated. Results revealed that (1) level of TB in the polyculture was constantly higher than in the monoculture over a 6.5-day period. While levels of TV in the polyculture was detected to be constantly lower than in the monoculture, (2) integration of G. textorii in the abalone culture changed the Vibrio compositions in the water as judged by the changes of bacteria colony types; (3) application of artificial diet led to dramatic increase of the levels in TB and TV in both systems at 12 h after application in the 24-h test and resulted in selective propagation of Vibrio in the water in the monoculture system; (4) polyculture of G. textorii with juvenile abalone in combination with feeding with live algal diet helped to maintain low levels of TV and the balance of the Vibrio composition; (5) living biomass of G. textorii was effective in preventing propagation of two purified Vibrio strains (V alginolaticus and V logei) in the water. These results provide a general basis of the dynamic changes of levels in TB and TV in a seaweed-abalone polyculture system with or without artificial diet in tanks. (c) 2005 Elsevier B.V All rights reserved.

THE COMPOUND EYE AS AN INDICATOR OF AGE AND SHRINKAGE IN ANTARCTIC KRILL

Laboratory studies have shown that Antarctic krill (Euphausia superba) shrink if maintained in conditions of low food availability. Recent studies have also demonstrated that E. superba individuals may be shrinking in the field during winter. If krill shrink during the winter, conclusions reached by length-frequency analysis may be unreliable because smaller animals may not necessarily be younger animals. In this study, the correlation between the body-length and the crystalline cone number of the compound eye was examined. Samples collected in the late summer show an apparent linear relationship between crystalline cone number and body-length. From a laboratory population, it appears that when krill shrink the crystalline cone number remains relatively unchanged. If crystalline cone number is little affected by shrinking, then the crystalline cone number may be a more reliable indicator of age than body-length alone. The ratio of crystalline cone number to body-length offers a method for detecting the effect of shrinking in natural populations of krill. On the basis of the crystalline cone number count, it appears from a field collection in early spring that E. superba do shrink during winter.

Seasonal thermogenesis and body mass regulation in plateau pikas (Ochotona curzoniae)

Changes in photoperiod, ambient temperature and food availability trigger seasonal acclimatization in physiology and behavior of many animals. In the present study, seasonal adjustments in body mass and in several physiological, hormonal, and biochemical markers were examined in wild-captured plateau pikas (Ochotona curzoniae) from the Qinghai-Tibetan plateau. Our results showed that plateau pikas maintained a relatively constant body mass throughout the year and showed no seasonal changes in body fat mass and circulating levels of serum leptin. However, nonshivering thermogenesis, cytochrome c oxidase activity, and mitochondrial uncoupling protein 1 (UCP1) contents in brown adipose tissues were significantly enhanced in winter. Further, serum leptin levels were positively correlated with body mass and body fat mass while negatively correlated with UCP1 contents. Together, these data suggest that plateau pikas mainly depend on increasing thermogenic capacities, rather than decreasing body mass, to cope with cold, and leptin may play a potential role in their thermogenesis and body mass regulation.

The effect of supplementary feeds on the bodyweight of yaks in cold season

The present study was conducted to determine the effects of supplementary feeds, oat hay (OH), highland barley straw (HBS) and multi-nutrient blocks supplementation (UMMB) on reducing liveweight losses of both yak cows and calves grazed on low quality pastures during cold season. The trials of OH and HBS supplementation were conducted by using completely random design on 104 yak cows between 6 and 12 years of age as the following treatments: pure grazing (41 animals, body weight 230 67 kg) as control (CK); grazing+1.5 kg DM of OH per head daily (30 animals, body weight 216 28 kg); gazing. 1.5 kg DM of HBS per head daily (33 animals, body weight 221 34 kg). The trial of UMMB was conducted on three types of yaks, 1-year calves (8-12 months old, body weight 61.1 6.9 kg), 2-year calves (18-24 months old, 98.0 11.3 kg) and yak cows (164.5 27.1 (S.D.) kg) with 20 animals in control group (CK) and 20 animals in supplement group for each type by using completely random design as the following treatments: pure grazing for CK group; grazing+ 150, 250 and 500 g UMMB per day averagely for 1-year calf, 2-year calf and cow at night. The results indicate that the animals supplemented with oat hay received body weight gain (32 20.7 g day(-1)), while those supplemented with highland barley straw still suffered from body weight loss (-56.7 39.3 a day(-1)); UMMB supplementation can decrease the body weight loss by 109.7%, 86.6% and 63.4% for the 1-year calves, 2-year calves and yak cows, respectively, as compared with pure grazing. Around US$1.60 output can be achieved on the basis of US$1 input for UMMB supplementation in the farming systems of the 1-year calves, 2-year calves and yak cows, while US$1 input can produce US$1.55 and 1.14 output for OH and FIBS supplementations, respectively, in yak cows' farming system. It can be preliminary concluded that UMMB supplementation was the most economic way to alleviate body weight loss of grazing yaks over cold season, and the higher productive returns were obtained from OH supplementation for grazing yak cows during winter/spring months. © 2004 Elsevier B.V All rights reserved.

A preliminary discussion on the bio-metallogenesis of Tl deposits in the low-temperature minerogenetic province of southwestern China

Starting with the research status of bio-metallogenesis of Tl deposits and their geology, this work deals with the geological background of Tl enrichment and mineralization and the mechanism of bio- metal-logenesis of Tl deposits, as exemplified by Tl deposits in the low-temperature minerogenetic province. This research on the bio-metallogenesis of Tl deposits is focused on the correlations between bio-enrichment and Tl, the enrichment of Tl in micro-paleo-animals in rocks and ores, bio-fossil casts in Tl-rich ores, the involvement of bio-sulfur in minerogenesis and the enrichment of bio-genetic organic carbon in Tl ores. Thallium deposits have experienced two ore-forming stages: syngenetic bio- en-richment and epigenetic hydrothermal reworking (or transformation). Owing to the intense epigenetic hydrothermal reworking, almost no bio-residues remain in syngenetically bio-enriched Tl ores, thereby the Tl deposits display the characteristics of hydrothermally reoworked deposits.