Different Patterns Of Behavior Research Articles

Risk factors for HIV infection among sex workers in Johannesburg, South Africa

Our objective was to determine the prevalence and risk factors for HIV infection among female sex workers in Johannesburg, South Africa. A cross-sectional survey of female sex workers was conducted using interviewer-administered questionnaires. Prevalent sexually transmitted infections including HIV were evaluated through standard laboratory testing. HIV infection was identified in 137 (46.4%) of 295 subjects tested. Increasing frequency of condom use was significantly negatively associated with HIV infection (odds ratio [OR] for moderate use = 0.21; 95% confidence interval [CI]: [0.09, 0.50]; OR for high use = 0.14; 95% CI: [0.06, 0.34]). Sex workers aged > or = 29 years reported significantly different patterns of behaviour than younger workers. Among women aged > or = 29, a negative association with HIV infection (OR = 0.16; 95% CI: [0.07, 0.38]) was found, but only among those not infected with Neisseria gonorrhoeae. Older women in the Johannesburg sex industry may have adaptive behavioural strategies besides condom usage which reduce their risk of acquiring HIV. However, older sex workers with gonorrhoea constitute a high-risk subgroup.

Collision mechanisms in one-electron capture byHe2+ions in collisions with hydrocarbons

Translational energy spectroscopy has been used to study one-electron capture by 200-2000 eV amu{sup -1} He{sup 2+} ions in CH{sub 4}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6}. The main He{sup +}(n,l) excited product channels have been identified and their relative importance assessed. Although significantly different patterns of behavior are observed, all three cases exhibit the highly selective nature of the electron capture process in spite of the large number of possible nondissociative and dissociative product channels associated with a wide spread in energy defects {delta}E.

Bullies, aggressive victims, and victims: Are they distinct groups?

This study analyzed a sample representing six middle schools that included 206 pure bullies, 514 pure victims, and 206 aggressive victims. Aggressive or provocative victims are students who have been bullied but also bully other students. This research assessed whether aggressive victims engaged in different patterns of behavior and had dissimilar socialization experiences than pure bullies and pure victims. Factors that were considered include measures of parental socialization, family conflict, reactive and proactive aggression, low self-control, social bonds, and other relevant factors, including demographic characteristics. Logistic regression analyses indicated that aggressive victims engaged in significantly different patterns of behavior than pure victims and pure bullies. The analyses also indicated that the socialization experiences of middle school aggressive victims more closely resembled the socialization experiences of pure bullies than pure victims. Aggr. Behav. 00:00–00, 2005. © 2005 Wiley-Liss, Inc.

Thermal dependence of chemical assessment of predation risk affects the ability of wall lizards, Podarcis muralis, to avoid unsafe refuges

Prey often respond to predators by increasing refuge use, but some refuges may expose prey to other types of predators. Because predators are not always visible inside refuges, their chemical stimuli may provide early warning of their presence. However, in ectotherms, chemosensory detection of predators may be thermally dependent. Lizards often hide in cold refuges, where their body temperature (Tb) may decrease, and this might affect their ability to detect chemicals of saurophagous snakes that ambush inside refuges. We examined the effects of Tb of wall lizards, Podarcis muralis, on their ability to detect chemicals of smooth snakes, Coronella austriaca. Differential tongue flick (TF) rates and behavioral patterns of lizards in response to scent of smooth snakes showed that lizards with optimal Tb discriminated and avoided the snake's scent, whereas lizards with suboptimal Tb did not. We also examined the importance of this effect on movement patterns and refuge use by lizards in terraria with safe (odorless) or unsafe refuges (snake-scented). While results of this experiment were variable, there was evidence of snake avoidance in that lizards at optimal Tb spent less time in snake-scented refuges relative to odorless refuges. Therefore, this study provides evidence that chemosensory discrimination of snake chemicals is thermally dependent, and, thus, suboptimal Tb impedes a lizard's ability to avoid snake-scented refuges.

Field study of the influence of meteorological factors and traffic volumes upon suspended particle mass at urban roadside sites of differing geometries

Abstract Twenty-four hour averaged concentrations of PM2.5 and PM10 have been measured at UK urban sites using dichotomous samplers. Four site pairs have been selected, each of which comprises a busy roadside site and a nearby urban background location. Differences between roadside and urban background concentrations are interpreted in terms of street geometry and atmospheric circulations. Markedly different patterns of behaviour are observed between the more enclosed and more open sites. At the former, the traffic increment in particle mass (difference between roadside and background sites) tends to be independent of the magnitude of concentrations. At the more open sites, there is a tendency for the traffic increment in particle mass to increase with increasing concentration. At one site, with an asymmetric building configuration across the street, the behaviour is wind-direction dependent with higher traffic increments observed when the air above the urban canopy passes first over the taller buildings before apparently creating a recirculating vortex over the roadway. Incremental coarse to incremental fine particle ratios vary greatly between sites (0.21–0.61 on average), the values increasing with the total traffic volume at the site.

The contribution of symmetry and motion to the recognition of faces at novel orientations

In three experiments, we examined the recognition of faces at novel orientations. Although performance tended to decay as difference between the study and the test angles increased, an orientation that was symmetric with respect to the study orientation showed strong performance--in many cases, better than the frontal view. We investigated the properties of this particular facility in perception and memory tasks. Symmetrized faces showed surprisingly different patterns of behavior than did unsymmetrized faces, despite the fact that many faces were already fairly symmetric. In memory experiments, the subjects showed robust symmetric orientation effects and could differentiate between the original study views and the symmetric orientation. In a third experiment, we demonstrated that smooth motion improved performance at the symmetric orientation, whereas two control motions did not. Together, the three experiments support the view that multiple representations are at work during the recognition of faces at the symmetric orientation and that, during memory tasks, subjects tend to rely on representations that are more robust against texture asymmetries and that may include limited depth information.

Thermal dependence of chemical assessment of predation risk affects the ability of wall lizards, Podarcis muralis, to avoid unsafe refuges

Prey often respond to predators by increasing refuge use, but some refuges may expose prey to other types of predators. Because predators are not always visible inside refuges, their chemical stimuli may provide early warning of their presence. However, in ectotherms, chemosensory detection of predators may be thermally dependent. Lizards often hide in cold refuges, where their body temperature (Tb) may decrease, and this might affect their ability to detect chemicals of saurophagous snakes that ambush inside refuges. We examined the effects of Tb of wall lizards, Podarcis muralis, on their ability to detect chemicals of smooth snakes, Coronella austriaca. Differential tongue flick (TF) rates and behavioral patterns of lizards in response to scent of smooth snakes showed that lizards with optimal Tb discriminated and avoided the snake's scent, whereas lizards with suboptimal Tb did not. We also examined the importance of this effect on movement patterns and refuge use by lizards in terraria with safe (odorless) or unsafe refuges (snake-scented). While results of this experiment were variable, there was evidence of snake avoidance in that lizards at optimal Tb spent less time in snake-scented refuges relative to odorless refuges. Therefore, this study provides evidence that chemosensory discrimination of snake chemicals is thermally dependent, and, thus, suboptimal Tb impedes a lizard's ability to avoid snake-scented refuges.

Scientific advances provide opportunities to improve pediatric environmental health

Scientific advances provide opportunities to improve pediatric environmental health

Molecular markers to study population structure and dynamics in beneficial insects (predators and parasitoids)

For beneficial insects--predators and parasitoids--to be used effectively within pest control scenarios, it is often necessary to have fundamental as well as more applied information about them, including data on population dynamics, host switching and breeding systems. In recent years, such information has been gained by the use of molecular DNA markers. In this article, we briefly discuss the range of molecular markers available and their potential uses, concentrating on how particular markers have been employed to unravel different patterns of behaviour. Whilst alternative methods of tracking insects have proved highly informative when applied over small geographical scales (e.g., fluorescent dyes and radar transponders as attached to bees, etc), these approaches tend to be confined to studies of movement rather than other potentially important behaviours.

Health care seeking behavior of Korean women with lymphedema.

The present biocultural study aimed to describe the health care use patterns of women with lymphedema. Data came from interviews and participant observations with eight key informants between February 2000 and February 2002. Analyzing the process of seeking health care, this paper explored how Korean women with lymphedema make use of all the available resources in the three sectors of the health care system: professional, folk and popular health. In these three sectors of the health care system, informants showed different patterns of behavior. In the professional health care sector, they behave based on scientific Western medicine and holistic herbal medical frameworks. Informants want scientific technological treatment from a Westernized doctor and perfect humanistic and holistic treatment from a herbal doctor. In the folk sector, informants' behavior is ruled by a pragmatic and supernatural framework. Informants seek religious healers who have strong spirituality and non-religious healers who have experience and skills. Informants complied with these healer's remedies based on efficacy and empirical healing evidence. In the popular sector of the health care system, informants behave based on their concept of illness and rules of daily life. They believe lymphedema comes from poor blood circulation and they want to be regarded as members of society, not as patients with lymphedema. Therefore, informants practised popular remedies that they believed were good for promoting blood circulation and keeping their social network active. This description about health care seeking behaviors being embedded in Korean socio-medical culture can serve to understand patients with other chronic health problems. With these results, we can put a bridge over the river of cultural conflict between health professionals and patients.

On the international stability of health care expenditure functions: are government and private functions similar?

This paper studies the stability of health care expenditure functions in a sample of OECD countries. We adopt the cointegration approach and the results show that there is a long-term relationship between total health care expenditure (HCE) and gross domestic product (GDP). However, the existence of cointegration is only shown when we admit the presence of some changes in the elasticities of the model. Our results also provide evidence against the existence of a unique relationship between health and GDP for the sample. Thus, we can conclude that the differences in health systems may cause differences in the aggregate functions. Additionally, we examine aggregate health functions for government (GHCE) and private expenditures (PHCE), again finding evidence of different patterns of behaviour. Finally, we open a discussion on the character of health as a necessary or luxury good. In this context, we find differences between the government and the private function. In order to illustrate these findings, we propose a theoretical model as an example of the influence of political decisions on income elasticity.

The motor infrastructure: from ion channels to neuronal networks

The vertebrate motor system is equipped with a number of neuronal networks that underlie different patterns of behaviour, from simple protective reflexes to complex movements. The current challenge is to understand the intrinsic function of these networks: that is, the cellular basis of motor behaviour. In one vertebrate model system, the lamprey, it has been possible to make the connection between different subtypes of ion channels and transmitters and their roles at the cellular and network levels. It is therefore possible to link the role of certain genes or molecules to motor behaviour in this system.

In vivo changes of the oxidation-reduction state of NADP and of the ATP/ADP cellular ratio linked to the photosynthetic activity in Chlamydomonas reinhardtii.

The ATP/ADP and NADP/NADPH ratios have been measured in whole-cell extract of the green alga Chlamydomonas reinhardtii, to understand their availability for CO(2) assimilation by the Calvin cycle in vivo. Measurements were performed during the dark-light transition of both aerobic and anaerobic cells, under illumination with saturating or low light intensity. Two different patterns of behavior were observed: (a) In anaerobic cells, during the lag preceding O(2) evolution, ATP was synthesized without changes in the NADP/NADPH ratio, consistently with the operation of cyclic electron flow. (b) In aerobiosis, illumination increased the ATP/ADP ratio independently of the intensity used, whereas the amount of NADPH was decreased at limiting photon flux and regained the dark-adapted level under saturating photon flux. Moreover, under these conditions, the addition of low concentrations of uncouplers stimulated photosynthetic O(2) evolution. These observations suggest that the photosynthetic generation of reducing equivalents rather than the rate of ATP formation limits the photosynthetic assimilation of CO(2) in C. reinhardtii cells. This situation is peculiar to C. reinhardtii, because neither NADPH nor ATP limited this process in plant leaves, as shown by their increase upon illumination in barley (Hordeum vulgare) leaves, independent of light intensity. Experiments are presented and were designed to evaluate the contribution of different physiological processes that might increase the photosynthetic ATP/NADPH ratio-the Mehler reaction, respiratory ATP supply following the transfer of reducing equivalents via the malate/oxaloacetate shuttle, and cyclic electron flow around PSI-to this metabolic situation.

Understanding Urban Growth: a Conceptual Model

Understanding the urban growth system is a prerequisite for modelling and forecasting future trends of urban land use/cover change and its ecological impacts. As urban growth involves various actors with different patterns of behaviour, we argue that scientific understanding must be based on elaborated complexity theory and a multidisciplinary framework. The theoretical analysis can provide a guideline for selecting modelling methods currently available in complexity modelling and in remote sensing and GIS environments. This paper first proposes a conceptual model for defining urban growth and its complexity, in which spatial, temporal and decision-making complexity are distinguished as separate domains. Second, this paper links the conceptual model with the major current methods of modem urban modelling, such as cellular automata, fractals, neural networks, multi-agent, spatial statistics etc. This confrontation enables the possibilities of various modelling methods to understand urban growth complexity to be indicated. Third, this paper evaluates the operational implementation of representative methods based on criteria such as interpretability, data need and GIS embedded ness. Finally, two case studies are used to test the conceptual model.

Modelling Urban Growth Patterns: A Multiscale Perspective

Urban development is a complex dynamic process involving various actors with different patterns of behaviour. Modelling urban development patterns is a prerequisite to understanding the process. This paper presents a preliminary multiscale perspective for such modelling based on spatial hierarchical theory and uses it for the analysis of a rapidly developing city. This framework starts with a conceptual model, which aims at linking planning hierarchy, analysis hierarchy, and data hierarchy. Analysis hierarchy is the focus of this paper. It is divided into three scales: probability of change (macro), density of change (meso), and intensity of change (micro). The multiscale analysis seeks to distinguish spatial determinants on each of the three scales, which are able to provide deeper insights into urban growth patterns shaped by spontaneous and self-organised spatial processes. A methodology is also presented to implement the framework, based on exploratory data analysis and spatial logistic regression. The combination of both is proven to have strong capacity of interpretation. This framework is tested by a case study of Wuhan City, China. The scale-dependent and scale-independent determinants are found significantly on two scales.

Use of Choice to Identify Behavioral Function Following an Inconclusive Brief Functional Analysis

In the current investigation, a concurrent operant paradigm was used with 3 young children who displayed severe problem behaviors to identify behavioral function. The children were given a series of choice options varying the availability of parent attention, access to preferred toys, and level of demand. The results showed that all children displayed differential patterns of behavior that appeared to be influenced by the presence or absence of attention and demands, suggesting a behavioral function. The results extended previous applications of reinforcer assessment procedures by using choice to identify antecedent conditions that set the occasion for problem behavior.

Recruitment patterns of decapod crustacean megalopae in a shallow inlet (SW Spain) related to life history strategies

Decapod crustacean megalopae were sampled weekly (spring/neap tides) during late-spring/summer of 1998 by using two planktonic nets located close to the surface and the bottom, at a fixed station in the mouth of the Rı́o San Pedro inlet (SW Spain). Sampling was carried out during 25 h cycles to ascertain the flux of megalopae in relation to the main environmental (diel, tidal, tidal amplitude) cycles. The hypothesis that megalopae of some species may be using tidal-stream transport as a mechanism of re-invading the inlet was tested and the relationship between megalopal behaviour and life history strategy was analysed. In general, the flux of megalopae was higher during spring tides, but such differences were only statistically significant for Pisidia longicornis and Liocarcinus sp.2 due to the considerable interdate variation. With the exception of Macropodia sp., megalopae were more abundant close to the bottom. The diel/tidal flux of most abundant species suggested two different patterns of behaviour: megalopae of Liocarcinus spp., Panopeus africanus, Uca tangeri and Brachynotus sexdentatus seemed to be re-invading the inlet (specially at nocturnal floods), while megalopae of Ilia nucleus, Nepinnotheres pinnotheres and Macropodia sp. may have been just looking for a suitable place for settlement. The first group corresponded to the species whose zoeal development occurs in open sea, and the second one to species that complete their life cycle within the studied system, suggesting a relationship between the duration of the larval phase and the life cycle strategy of the species.

All are one and one is all: sexual uniformity among widely separated populations of the North American seal salamander, Desmognathus monticola

The Modern Synthesis of the mid-20th century effectively buried typological definitions and descriptions of species and their boundaries. This interment is well supported by the large number of animal species for which substantial levels of sexual incompatibility have been found among conspecific populations, including some species of North American desmognathine salamanders that have restricted geographical ranges. We tested for sexual incompatibility and variation in sexual signals and responses among widely separated populations of the broadly distributed seal salamander, Desmognathus monticola . Levels of sexual incompatibility and differences in behaviour patterns exhibited during courtship and mating were modest to non-existent among these populations, despite the considerable geographical distances separating some of them. Our data are not consistent with results obtained in the majority of similar studies that have been conducted on congeneric species. For the seal salamander, we cannot reject the applicability of a typological species definition based on sexual compatibility and uniformity in the ethology of courtship among populations. We present five hypotheses (not necessarily mutually exclusive) that may explain our results. We suggest that recent range expansion, perhaps coupled with contemporary gene flow, may best explain sexual uniformity among populations of the seal salamander. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 78, 1–10.

On the applicability of cross-anisotropic elasticity to granular materials at very small strains

The paper examines the validity of assuming that granular material behaviour can be considered as cross-anisotropic, linear elastic, within a kinematic ‘kernel’ yield surface that is dragged through stress space with the current effective stress point. Data from more than 300 high-resolution triaxial probing and bender element tests performed on 15 samples are reported in which both small stress cycles and shear wave measurements in both the vertical and horizontal directions were conducted on sand and glass ballotini specimens under various effective stress states. It was found that behaviour is not fully elastic. However, provided the effective stress ratio, R, was kept below around 2·2, most features of the very small-strain behaviour could be described in terms of strongly anisotropic compliance terms that varied with void ratio and current effective stress state, apparently independently of the specimen's stress history. The anisotropy depended on the effective stress states. Specimens loaded to R values exceeding 2·2 that experienced shear-induced dilation followed different patterns of behaviour. The concept of a kinematic closed elastic yield surface, or ‘kernel’, proved to be an appropriate way of describing the pronounced effects of recent stress history on the apparent limits to the linear range observed in a wide range of stress probing tests.

On the applicability of cross-anisotropic elasticity to granular materials at very small strains

The paper examines the validity of assuming that granular material behaviour can be considered as cross-anisotropic, linear elastic, within a kinematic ‘kernel’ yield surface that is dragged through stress space with the current effective stress point. Data from more than 300 high-resolution triaxial probing and bender element tests performed on 15 samples are reported in which both small stress cycles and shear wave measurements in both the vertical and horizontal directions were conducted on sand and glass ballotini specimens under various effective stress states. It was found that behaviour is not fully elastic. However, provided the effective stress ratio, R, was kept below around 2·2, most features of the very small-strain behaviour could be described in terms of strongly anisotropic compliance terms that varied with void ratio and current effective stress state, apparently independently of the specimen's stress history. The anisotropy depended on the effective stress states. Specimens loaded to R values exceeding 2·2 that experienced shear-induced dilation followed different patterns of behaviour. The concept of a kinematic closed elastic yield surface, or ‘kernel’, proved to be an appropriate way of describing the pronounced effects of recent stress history on the apparent limits to the linear range observed in a wide range of stress probing tests.