Complex sociogenetic organization and the origin of unrelated workers in a eusocial sweat bee, Lasioglossum malachurum

Sweat bees (Halictidae) exhibit great interspecific and intraspecific diversity in their social organisation, yet there is remarkably little information on the sociogenetic organisation of any species. Lasioglossum malachurum is a eusocial sweat bee with an annual lifecycle that exhibits considerable variation in its social organisation across its wide geographic range from northern to southern Europe. We collected all adults from 31 L. malachurum nests at Eichkogl, Austria, near the latitudinal centre of its distribution, and genotyped 148 workers using 5 highly variable microsatellite loci developed for this species. Nests were often queenless (48% of nests) during the second phase of worker activity, when colonies were provisioning the sexual brood. Pedigree reconstruction and estimates of nestmate genetic relatedness demonstrated that nests often (32% of nests) contained alien workers, probably as a result of worker drifting from their natal to a foreign nest. Queen effective mating frequency was variable (harmonic mean m_e = 1.24), but sometimes high (maximum 2.7). These data demonstrate that nests of L. malachurum do not have a classical eusocial sociogenetic organisation (monogyny, monandry) and thereby pose a challenge to exclusively relatedness based arguments for the evolution of eusociality in the taxon. Received 6 June 2008; revised 1 October 2008; accepted 13 October 2008.     

Modeling the HIV/AIDS Epidemic Among Injecting Drug Users and Sex Workers in Kunming, China

This paper presents a mathematical model of the HIV/AIDS epidemic in Kunming,the provincial capital of Yunnan, China. The population is divided into several groups, with individuals possibly changing group. Two transmission routes of HIV are considered: needle sharing betweeninjecting drug users (IDUs) and commercial sex between female sex worker(FSWs) and clients. The model includes male IDUs who are also clients and female IDUs who are also FSWs. Groups are split in two—risky and safe—according to condom use and needle sharing. A system of partialdifferential equations is derived to describe the spread of the disease. For the simulation, parameters are chosen to fit as much as possibledata publicly available for Kunming. Some mathematical properties of the model—in particular the epidemic threshold R ⁰ which determines the goal of public health interventions—are also presented. Though the model couples two transmission routes of HIV, the approximation , with closed formulas for and , appears to be quite good. The critical levels of condom use and clean needle use necessary to stop both the sexual transmission and the transmission among IDUs can therefore be determined independently.     

Acculturation strategies used by unskilled migrant workers in South Korea

The purpose of this study is to identify types of adaptation strategies used by unskilled migrant workers living in South Korea as they acculturated to life in the country and to determine specific characteristics by acculturation patterns. To this end, a Q methodology was used. A total of fifty-nine statements were drawn through in-depth interviews with eight migrant workers and two South Koreans working in related organizations as well as from thirteen other studies, and four factor types of acculturation patterns were identified by conducting a Q sorting on thirty-eight subjects. Interpretation of the study revealed that the subjects used four types of adaptation strategies: accepted separation, compromising integration, conflict marginalization, and harmonious assimilation. The subjects in each type showed concrete socio-psychological adaptation strategies in response to South Korea’s unique culture and policies of discriminative exclusion.     

闽东一水电站输水管道阻塞原因探讨

对福建省闽东某水电站水库的水体及地下输水管道中的微生物生态和理化因子的调查分析结果表明,造成该水库电站输水管道连年阻塞的主要原因可能是由于铁细菌生长繁殖所致。该水库中的铁细菌主要为鞘细菌。水体温度及总铁含量对鞘细菌数量的消长具有显著影响。该水库中存在的鞘细菌最适生长条件为Ｔ２１～２５℃,ｐＨ６．１６～６．８７,Ｆｅ＞０．４３ｍｇ／Ｌ。该菌可在水深０．５～４０ｍ范围内生存。自然气候对Ｔ、总铁和悬浮物３项水体理化因子有影响,而ｐＨ、ＤＯ和ＣＯＤ则受微生物生命活动的影响。夏季为鞘细菌繁殖高峰期。建议电站地下输水管道的疏通工作以安排在９月份之后较妥     

Dynamic variation of histone H3 trimethyl Lys4 (H3K4me3) and heterochromatin protein 1 (HP1) with employment length in nickel smelting workers

Objective: To investigate the dynamic variation in H3K4me3 and HP1 with employment length in nickel smelting workers.

Methods: Blood samples were collected from 140 nickel smelting workers and 140 age-matched office workers to test for H3K4me3, and HP1 levels.

Results: H3K4me3 was statistically significantly different (p?<?0.05) between the two groups and positively correlated with employment length (r_s?=_?0.267). HP1 was not correlated with employment length (p?=?0.066) but was significantly different between the two groups.

Conclusions: Chronic exposure to nickel can induce oxidative damage, and increase H3K4me3 expression and inhibit HP1 expression.     

Hair,serum, and urine chromium concentrations in former employees of the leather tanning industry

In this study, we measured concentrations of Cr in hair, serum, and urine of men who were previously employed in the leather tanning industry. Concentrations of Cr in hair and serum were significantly lower than corresponding values obtained during their employment and were comparable to levels obtained for controls in a previous study. These results suggest that Cr III accumulated from employment in the leather tanning industry does not result in longterm elevation of Cr concentrations in the body     

Behaviour and performance of juvenile shortnose sturgeon Acipenser brevirostrum at different water velocities

Critical swimming speeds (mean ± s . e .) for juvenile shortnose sturgeon Acipenser brevirostrum were 34·4 cm s⁻¹± 1·7 (2·18 ± 0·09 body lengths, BL s⁻¹). Swimming challenges at 10, 20 and 30 cm s⁻¹ revealed that juvenile A. brevirostrum are relatively poor swimmers, and that the fish did not significantly modify their swimming behaviour, although they spent more time substratum skimming ( i.e. contact with flume floor) at 30 cm s⁻¹ relative to 10 cm s⁻¹. When present, these behavioural responses are probably related to morphological features, such as flattened rostrum, large pectoral fins, flattened body shape and heterocercal tail, and may be important to reduce the costs of swimming.     

Influence of larvae and workers on egg production of queens of the pharaoh's ant,Monomorium pharaonis (L.)

Summary Social regulation of egg production and weight in queens was studied in relation to presence and absence of larvae and workers in the pharaoh's ant,Monomorium pharaonis (L.).Results were obtained by counting eggs and weighing queens under various conditions.The results confirm the existence of a positive feed-back loop between mated queens and their larvae as evident from a correlation (Y = 4.575 * X + 6.452) between the number of large worker larvae (X) and the egg yield (Y). This correlation seems to relate to the queens preferential feeding on larval secretions. Queens without larvae maintained a low level of egg production of about 6 eggs/day. Queens deprived of larvae as well as workers stopped producing eggs within 24 hours.Repletes, special workers, with greatly distended gasters functioned as a buffer retarding decline of egg production by feeding the queens during short periods without larvae.     

Dynamics of cuticular chemical profiles of Polistes dominulus workers in orphaned nests (Hymenoptera, Vespidae)

We analysed changes in cuticular hydrocarbon signatures of workers in orphaned colonies of the paper wasp Polistes dominulus. In natural conditions, workers and foundresses possess characteristic cuticular signatures, and foundresses are further distinguishable, both behaviourally and chemically, on the basis of their rank in a reproductive dominance hierarchy. In our study, several workers were found to develop their ovaries and produce cuticular signatures resembling those of dominant foundresses, while remaining workers possessed undeveloped ovaries and had cuticular blends characteristic of subordinate foundresses. Workers that did not develop their ovaries had changed epicuticular signatures, demonstrating that the mixture of hydrocarbons of worker individuals is strongly dependent on social role and environment. Our results suggest that the composition of epicuticular lipids is not determined at the pre-imaginal stage, and that physiological pathways leading to cuticular chemical changes are similar in foundresses and workers of P. dominulus.     

Foreigners or multicultural citizens? Press media's construction of immigrants in South Korea

This paper examines the ways in which new immigrants to South Korea are portrayed and constructed in press media. The influx of labour and marriage migrants from Southeast Asia and China to South Korea since the early 1990s has been significant enough to cause national concerns about diversity and the country's future as a multiethnic society. Mainstream newspapers in South Korea have been a major shaper of the public opinion of diverse groups of immigrants whose presence is becoming increasingly visible in this country with a strong self-image as a mono-ethnic nation. The ways in which these new immigrants, typically lower class, are constructed in public discourses expose the nexus of citizenship, class and ethnicity. Using articles from two major South Korean newspapers between 1990 and 2008 as data, the analysis highlights the economic and historical contexts in which public discourses on new immigrants have been formed and transformed.