Q460C高强度结构钢材循环加载试验研究

为了得到高强度钢材的滞回性能,对Q460C高强度结构钢材的单调和循环加载性能进行了试验研究.试验包括3个单调拉伸、3个单调压缩和10个不同加载制度的循环加载,得到了单调和循环加载的应力-应变曲线;分析了单调和循环加载下的宏观试验现象以及断口的电镜扫描结果.基于Ramberg-Osgood公式,对各种循环荷载下钢材的骨架...     

Reproductive behaviour and development dynamics of Odontophrynus cordobae (Anura,Cycloramphidae)

We provide detailed information on breeding sites, release call, satellite behaviour, courtship, and embryonic and larval development of Odontophrynus cordobae. Field observations were carried out during two breeding seasons (2004–2005 and 2008–2009). Clutches were raised in captivity (artificial ponds) to analyse the development of embryos and tadpoles. Breeding sites were represented by streams and their backwaters, as well as temporary and permanent ponds of varying sizes. Operational sex ratio was male-biased varying between 0.154 and 0.25. Acoustic activity started about 8–10 pm and ended between 2 and 4 am the next day. Distance among calling males was approximately three metres. Male satellite behaviour was observed. Amplexus attempts among males were common. Release calls were structurally similar although shorter than advertisement calls. Courtship and formation of amplexus were documented.     

In situ observations on behaviour of the ommastrephid squid genus Illex (Cephalopoda: Ommastrephidae) in the northwestern Atlantic

We compiled observations of ommastrephid squid of the genus Illex, primarily Illex illecebrosus from archived submarine video footage recorded during dives off Cape Hatteras and New England, and in the Gulf of Mexico. Based on the behaviour observed, we derived a partial in situ ethogram, or catalogue of the body patterns and behaviour. In total, 36 components were observed: 16 chromatic components (5 light and 11 dark), 10 postural components and 10 locomotor components. Co-occurrence analyses were used to show that specific sets of components occurred together either more or less often than they would if chosen at random. In addition, some of the components were observed occurring during specific behaviours, such as bottom sitting, hunting, or schooling. Such observations by submersibles also provide very precise, although incomplete, records of depth distribution. We summarize the depths and altitudes above bottom of these observations by time of day. Most of the squid were observed near bottom at depths of about 200–900 m. The deepest depths observed were during daytime and the shallowest during the evening. However, individuals were observed as much as 1000 m above the bottom during daytime whereas others were on or near the bottom in deep water during the evening.     

Natural history of the African riverine tiger beetle Chaetodera regalis (Dejean) (Coleoptera: Cicindelidae)

The tiger beetle Chaetodera regalis (Dejean) (Coleoptera: Cicindelidae) is widely distributed throughout sub-Saharan Africa. We studied activity patterns, ecological interactions, and behaviour of this species along four major rivers in Kruger National Park, South Africa. During the dry season, small numbers of adult beetles are found on sand bars along perennial rivers. In the rainy season, adults are found in large numbers on a broad spectrum of substrates (including clays, coarse and fine sands and gravels, and black organic soils) and geomorphological features (sand flats, mud flats, sand bars, beaches, riverbanks, and dry and wet sandy streambeds) in riverine areas. Predatory, defensive, thermoregulatory, and reproductive behaviours are described. This species may prove to be a useful indicator of the health of African riverine systems: adults are abundant in high-quality riverine areas; adults and larvae may be adversely affected by human activities; and adults are easily detected, even by novice surveyors.     

Mating behaviour and sexual selection in the African ball-rolling scarab Khepher platynotus (Bates) (Coleoptera: Scarabaeidae)

Mating behaviour of the ball-rolling dung beetle Kheper platynotus (Bates), adults of which are active in rainy seasons, was studied in southeastern Kenya. Male mating behaviour changed with the progression of the rainy season. In the early season when females made food balls, males attempted forced copulation with wandering and food-ball-making females on dung mounds. As the season progressed, females made brood balls, and males attempted to pair off with such females, as well as attempting forced copulation with wandering and food-ball-making females. A male who paired off with a brood-ball-making female cooperated with the female to make the ball. The male usually copulated after burying the ball (pre-copulatory mate guarding), but sometimes copulated during ball-making. In the latter case the male usually showed post-copulatory mate guarding until ball burial, but sometimes left soon after copulation. In the late season, when available females decreased because of maternal care in the underground nests, males started to make food balls to secure food resources for survival until the next rainy season. Male mate guarding involving ball-making, -rolling and -burying seemed to function to raise paternity confidence, but such assistance seemed to be less beneficial to females. Fights frequently occurred between guarding and intruding males on brood balls. Both residency and relative body sizes of fighters were important asymmetries influencing contest outcome. This seemed to result in not active but passive mate choice by brood-ball-making females.     

Life cycles and host–parasitoid relationships of five species of Leucospis wasps in Argentina (Hymenoptera: Leucospidae)

The genus Leucospis Fabricius is comprised of parasitoid wasps relatively uncommon in nature. Their immature stages develop on aculeate Hymenoptera, in particular solitary bees, but hosts are known for only around 25 Leucospis species (about 20% of 115–120 world species), so the true relationship of this family with bees is largely unknown. Here we report on individuals of five species of Leucospis wasps which emerged from nests of different bee and wasp species during distinct sampling periods during a trap-nesting programme, in two contrasting areas: agro-ecosystems and natural habitats in the Pampean region. Some of these nests were parasitised by L. cayennensis Westwood, L. coxalis Kirby, L. egaia Walker, L. pulchriceps Cameron and L. signifera Bou?ek. Our results expand the available information of host species for L. cayennensis, L. coxalis, L. egaia and L. pulchriceps and represent the first record of hosts associated with L. signifera. The hosts were only bee species of the genera Centris, Tetrapedia (family Apidae) and Megachile (Megachilidae). These species were more abundant in the natural reserve than in agro-ecosystems, suggesting that anthropogenic activities could negatively affect their populations. Most nests were attacked in one (43.7%) or two (40.7%) cells, but the remaining nests (16.5%) had more (up to seven cells). However, the position of the attacked cells was variable, suggesting that females of Leucospis species oviposit in recently built cells, and that the hatching of larvae is delayed, or that the first larval stage waits until the host larva reaches a sufficient size to attack.     

Nesting dynamic and sex allocation of the oil-collecting bee Centris (Heterocentris) analis (Fabricius, 1804) (Apidae: Centridini)

The study of nesting biology is an important biological aspect for both conservation and management, but despite this, only a few of the over 20,000 described bee species have had their nesting biology studied. The aim of this study was to describe and analyse the nesting biology and dynamic of an aggregation of the cavity-nesting bee species Centris analis during one generation. Twenty-eight females were marked and had their nesting activities documented, 64 nests were sampled, and 113 individuals emerged from these nests. An asymmetry in the sex allocation was observed for this species, and the sex ratio was male-biased in the first nests built. Nonetheless, considering an individual-level perspective, the females showed different strategies, with some of them producing more daughters, other females producing more sons, and still others producing an equal proportion. The productivity per female was low compared to that of other solitary bee species, and the females displayed an aggressive usurpation behaviour against conspecific females and performed an intraspecific parasitism. As the substrate used to nest is a limiting factor for this species, the usurpation behaviour may be an important strategy that could increase the chance of nesting. A few males used the nesting site as a resting place and the fidelity observed to this locale was high. This study provides new information about the natural history of this bee species, which is an important pollinator of both crops and native plant species.     

Interrelationships among noncooperative and coalition stability concepts

Insightful theorems are established on interrelationships among coalition and noncooperative stability concepts defined within the paradigm of the Graph Model for Conflict Resolution. More specifically, the newly defined coalition stability def＇mitions that are considered are coalition Nash stability （CNash）, coalition general metarationality （CGMR）, coalition symmetric metarationality （CSMR） and coalition sequential stability （CSEQ）, along with their earlier-defined noncooperative versions. A range of interesting new theorems are derived to establish connections among these coalition stability concepts as well as between noncooperative and coalition stability definitions. Applications with respect to the games of Prisoner＇s Dilemma and Chicken, as well as a groundwater contamination dispute, demonstrate how the various stability definitions can be applied in practice and confirm the validity of some of the theorems as well as point out, by example, certain types of relationships which cannot hold.