Morphological adaptation of the skull for various behaviors in the tree shrews

Skull size and shape were examined among 14 species of the tree shrews (Tupaia montana, T. picta, T. splendidula, T. mulleri, T. longipes, T. glis, T. javanica, T. minor, T. gracilis, T. dorsalis, T. tana, Dendrogale melanura, D. murina, and Ptilocercus lowii). The bones of face were rostro-caudally longer in T. tana and T. dorsalis, contrasting with T. minor and T. gracilis, D. melanura, D. murina and P. lowii which have smaller facial length ratios. The arbo-terrestrial species (T. longipes and T. glis) were similar to terrestrial species in length ratios of bones of face unlike the other arbo-terrestrial species (T. montana, T. picta, T. splendidula, and T. mulleri). We propose that T. longipes and T. glis have adapted to foraging for termites and ants as have T. tana and T. dorsalis. Additionally small body size in T. javanica may be the result of being isolated in Java. We separated the species into 5 groups from the measurment values of skulls: 1) Terrestrial species; T. tana and T. dorsalis, 2) Arboreal species; T. minor and T. gracilis, 3) Arbo-terrestrial species group 1: T. montana, T. splendidula, T. picta and T. mulleri, and T. javanica, 4) Arbo-terrestrial species group 2: T. glis and T. longipes, 5) Arboreal species of Dendrogale and Ptilocercus. Principal component analysis separated species into 8 clusters as follows: 1) T. tana, 2) T. dorsalis, 3) T. montana, T. splendidula, T. picta and T. mulleri, 4) T. glis and T. longipes, 5) T. javanica, 6) T. minor and T. gracilis, 7) D. melanura and D. murina, and 8) P. lowii. We suggest that these clusters correspond to behavioral strategies and peculiarities observed in foraging, feeding and locomotion in each species.     

Effects of ischemia and dimethyl sulfoxide on equine jejunal vascular resistance, oxygen consumption, intraluminal pressure, and potassium loss

Physiologic effects of 1 hour of ischemia and 1 hour of reperfusion on equine jejunum and protective effects of systemic administration of dimethyl sulfoxide (DMSO, 1 g/kg of body weight) were investigated in 18 ponies, using neurally intact segments of jejunum perfused at constant flow with heparinized blood. Ponies were allotted to 4 groups: group 1, saline solution administered (control, n = 3); group 2, DMSO administered (DMSO, n = 3); group 3, ischemia induced and saline solution administered (ischemia, n = 6); and group 4, ischemia induced and DMSO administered (ischemia-DMSO, n = 6). Intestinal vascular resistance (R, mm of Hg/ml/min/100 g), oxygen consumption (VO2, ml/min/100 g), frequency and amplitude of rhythmic changes in intraluminal pressure, intestinal compliance (C, ml/mm of Hg), and arteriovenous potassium concentration difference (delta AV [K+], mEq/L) were determined and compared with stable preischemic values within groups. There were no significant changes in any variable in ponies of groups 1 or 2. In ponies of group 3, significant (P less than or equal to 0.05) changes included: an initial increase in R during reperfusion, followed by a decrease to values below preischemic values by 15 minutes of reperfusion; decreased VO2 during the entire reperfusion period; increased amplitude of rhythmic contractions during initial reperfusion; decreased frequency of rhythmic contractions during ischemia; and increased delta AV [K+] during initial reperfusion. Changes in ponies of group 4 were identical to changes in ponies of group 3, with the exception that DMSO administration prevented the decrease in R during reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of distention and neostigmine on jejunal vascular resistance, oxygen uptake, and intraluminal pressure changes in ponies

The influence of distention (high baseline intraluminal pressure) and neostigmine methylsulfate on intestinal vascular resistance, oxygen uptake, and intraluminal pressure changes (rhythmic contractions) was studied in terminal jejunal segments, which were perfused at a constant rate, in 16 anesthetized ponies. When baseline intraluminal pressure was increased to 10 mm of Hg, the intestinal vascular resistance and amplitude of rhythmic contractions were increased. Neostigmine induced cyclic increases in amplitude of rhythmic contractions whether intraluminal pressure was 0 or 10 mm of Hg. Neostigmine also increased intestinal oxygen uptake at intraluminal pressures of 0 mm of Hg, but not at 10 mm of Hg, and vascular resistance was not altered at either intraluminal pressure. The results indicate that intestinal hemodynamics are adversely affected by distention. Further, neostigmine did not adversely affect intestinal hemodynamics while increasing rhythmic contractions, suggesting that neostigmine may be useful in the treatment of ileus in equids.     

应用碳分子筛气调机气调贮藏苹果对虎皮病的控制效果

碳分子筛气调机控制的 1—5 ％O_2 2—6％CO_2指标及气体循环净化,可明显抑制红元帅苹果表皮中α—法尼烯的合成和氧化,减少共轭三烯积累,将虎皮病控制在3％之下。在碳分子筛气调前附加高CO_2和乙氧基喹处理控制虎皮病与碳分子筛单一处理同效。     

T-cell receptor beta-chain expression: dependence on relatively few variable region genes

Fifteen independently isolated complementary DNA clones that contain T-cell receptor (TCR) V beta genes were sequenced and found to represent 11 different V beta genes. When compared with known sequences, 14 different V beta genes could be defined from a total of 25 complementary DNA's; 11 clones therefore involved repeated usage of previously identified V beta's. Based on these data, we calculate a maximum likelihood estimate of the number of expressed germline V beta genes to be 18 with an upper 95 percent confidence bound of 30 genes. Southern blot analysis has shown that most of these genes belong to single element subfamilies which show very limited interstrain polymorphism. The TCR beta-chain diversity appears to be generated from a limited V beta gene pool primarily by extensive variability at the variable-diversity-joining (V-D-J) junctional site, with no evidence for the involvement of somatic hypermutation.     

Impacts on soil quality from long-term irrigation with treated greywater

Drought condition in many places leads to the imperative use of greywater for irrigation. There is a serious concern on the impact of such prolonged uses on soil sustainability. The objective of this study was to evaluate the long-term impacts of greywater irrigation on soil electrical conductivity (EC) and other soil quality parameters in field conditions. Six locations were monitored in this study where home gardens have been irrigated with treated greywater for 2 years. Results showed a general reduction in EC levels of soil samples along all depth intervals at all locations. The average soil EC before greywater irrigation was 0.97 dS/m and decreased to 0.41 dS/m, which may be due to the use of greywater as well as the rainwater effect. The reduction in soil EC and irrigation water quantity shows positive correlation (correlation coefficient r = 0.64). Calcium precipitation might also have a major role in soil EC reduction. Soil calcium content was 81 mg L^?1 before using treated greywater and decreased to 43 mg L^?1 after 2 years of treated greywater usage, which might have been caused by calcium carbonates (CaCO₃) precipitation. The results of other soil chemical analyses clearly show that using treated greywater for irrigation has reduced the concentration of organic matters, K, Cd, Pb, P, Mg, Cl, Na, exchangeable sodium percentage, and sodium adsorption ratio after 2 years of application. Zn concentration increased from 11 to 15 mg L^?1, and soil pH became slightly higher from 7.6 to 7.8.     

Commercial marine fish farming in Singapore

Commercial marine fish farming in Singapore is mainly the culture of economically important foodfish species in floating cage nets. There are 84 licensed fish farms occupying 46.5 hectares (ha) of coastal waters. Production from these farms accounts for the bulk of aquaculture production in Singapore, being 3554 tonnes (‘metric tons’, t) in 1995, or 98% of total production of 3625t. The commonly cultured species are the green mussels, Perna viridis L., which form the bulk of production (70.4%), finfish like the groupers, Epinephelus tauvina Forsskal and E. malabaricus Schneider, Asian sea bass, Lates cakarifer Bloch, and snappers, Lutjanus johni Bloch and L. argentimaculatus Forsskal, and crustaceans like the mangrove crab, Scylla serrata Forsskal and spiny lobster, Panilurus polyphagus Herbst. The basic farm structure for fish and mussel culture is the floating wooden raft. In finfish farming, polyethylene cage nets are attached to the raft in which popular foodfishes are cultured. The mussel raft is a structure to which polyethylene ropes are attached to collect and grow out green mussels from natural spatfall. Fish seeds for farming are mostly wild-caught. Only the Asian sea bass and the banana shrimp (Penaeus merguiensis de Mann) are produced by commercial hatcheries in Singapore and the region. The fry of pompano (Trachinotus blochii Lacepede, and T. falcatus Klausewitz & Nielsen) are imported from Taiwan. Trash fish is still the main feed used for the farming of finfish and crustaceans like the mangrove crab and lobster because it is cheap and readily available. This paper also reviews the economics of commercial finfish and mussel farming in Singapore today.     

THE INVESTIGATION AND DEVELOPMENT OF CONTROLLED TEMPERATURE SYSTEM WITH MICROCOMPUTER

This paper introduces a controlled temperature system in which the silicon controlled rectifier is controlled by a TP-801 microcomputer. A common-used PID expression is usually applied to control temperature, but it is necessary to adjust three parameters, making the operation quite inconvenient. This system adopts the measurement of a simplified expanded-critical proportion, only one parameter is necessarily adjusted. In addition, the method of digital triggering is applied so that the D/A transfer and silicon adjuster are omitted, thus decreasing the cost and increasing the reliability of operation. This system has higher precision of control and better degree of linearity of temperature increment or decrement.     

北京地区圆柏新分类群形态及化学分类的研究

本文系研究北京地区圆柏新分类群的形态分类,并用过氧化物同功酶谱及氨基酸组成含量进行化学分类认证。确定圆柏属新增四栽培变种的形态特征。亲缘关系、利用特点,为栽培圆柏分类和良种选育提供新见解和资料。     

Cell corpse engulfment mediated by C. elegans phosphatidylserine receptor through CED-5 and CED-12

During apoptosis, phosphatidylserine, which is normally restricted to the inner leaflet of the plasma membrane, is exposed on the surface of apoptotic cells and has been suggested to act as an "eat-me" signal to trigger phagocytosis. It is unclear how phagocytes recognize phosphatidylserine. Recently, a putative phosphatidylserine receptor (PSR) was identified and proposed to mediate recognition of phosphatidylserine and phagocytosis. We report that psr-1, the Caenorhabditis elegans homolog of PSR, is important for cell corpse engulfment. In vitro PSR-1 binds preferentially phosphatidylserine or cells with exposed phosphatidylserine. In C. elegans, PSR-1 acts in the same cell corpse engulfment pathway mediated by intracellular signaling molecules CED-2 (homologous to the human CrkII protein), CED-5 (DOCK180), CED-10 (Rac GTPase), and CED-12 (ELMO), possibly through direct interaction with CED-5 and CED-12. Our findings suggest that PSR-1 is likely an upstream receptor for the signaling pathway containing CED-2, CED-5, CED-10, and CED-12 proteins and plays an important role in recognizing phosphatidylserine during phagocytosis.