Towards a general formalization of encounter rates in ecology

Although encounters between organisms are fundamental to many ecological processes, a general theory of encounters that accounts for random movements and probabilistic events has yet to be proposed. We present a framework for examining probabilistic encounters between arbitrarily moving searchers and immobile targets in continuous space and time. We define and contrast first encounter rates and mean encounter rates, which are generally not equal and depend on several properties of the process, including movement behaviors, the spatial scales of the encounter kernel, spatial distribution and birth–death dynamics of targets, and whether the encounters are destructive. Based on these considerations, we propose a taxonomy of encounter processes and discuss their functional relationships. Analytical approximations in several special cases are derived, leading to inference about general patterns. We identify, for example, cases (nondestructive, mean encounters) in which encounter rates are completely independent of movement velocity or tortuosity, and we quantify the dependence for cases (e.g., hard, first encounters and destructive encounters in a dynamic landscape) where there is a relationship. The analytical results lead to general qualitative conclusions, while the mathematical formalization and taxonomic organization provides a framework for studying and contrasting a broad range of encounter processes in ecology.     

Penelope as Dreamer: A Reading of Book 19 of The Odyssey

This essay reexamines the encounter between Odysseus and Penelope in Book 19 of Homer's epic poem The Odyssey, focusing particular attention on the dream of the 20 geese Penelope describes during that encounter. Odysseus, disguised as a beggar, says the dream is a favorable omen which indicates the real Odysseus will return soon to rid his palace of the hated suitors who have occupied it in his long absence. Although generations of scholars have agreed with the hero's interpretation, the present essay offers a different understanding: Penelope, having recognized who this beggar really is, has fabricated her dream of the 20 geese to test her husband and determine whether he is more interested in renewing their marriage or satisfying his vengeance against the suitors. The essay offers an appreciation of Penelope as one of our earliest and wisest dreamers, who understood how easily people's wishes and desires could lead them to misinterpret their own dreams and the dreams of others.     

Mixed encounters, limited perception and optimal foraging

This article demonstrates how perceptual constraints of predators and the possibility that predators encounter prey both sequentially (one prey type at a time) and simultaneously (two or more prey types at a time) may influence the predator attack decisions, diet composition and functional response of a behavioural predator-prey system. Individuals of a predator species are assumed to forage optimally on two prey types and to have exact knowledge of prey population numbers (or densities) only in a neighbourhood of their actual spatial location. The system characteristics are inspected by means of a discrete-time, discrete-space, individual-based model of the one-predator-two-prey interaction. Model predictions are compared with ones that have been obtained by assuming only sequential encounters of predators with prey and/or omniscient predators aware of prey population densities in the whole environment. It is shown that the zero-one prey choice rule, optimal for sequential encounters and omniscient predators, shifts to abruptly changing partial preferences for both prey types in the case of omniscient predators faced with both types of prey encounters. The latter, in turn, become gradually changing partial preferences when predator omniscience is considered only local.     

Global Politics and Multinational Health-care Encounters: Assessing the Role of Transnational Competence

This planets most likely political/population scenario for the 21st century anticipates more people, more spatial movement, and more transnational interactions. Global health increasingly will be shaped by encounters among clinicians and patients who meet in health-care settings where cultural, ethnic, and national-origin match is not an available option. In multinational clinical consultations, bicultural competence and lists of culture characteristics will not suffice. The article adapts the generic Koehn/Rosenau framework of transnational competence (TC), which encompasses analytic, emotional, creative, communicative, and functional skills, to the global challenge of providing migrant-health care. The focus is on the patient/clinician encounter, where interpersonal interactions carry the potential to reduce or reproduce existing inequities in health care. A structured literature review provides the basis for the adaptation to transnational health encounters presented for the first time here by incorporating recent research findings from more than 80 published studies regarding patient–provider consultations and cultural competence in the medical interview into the TC frameworks empirical foundation in cross-cultural psychology, development studies, intercultural communication, and international management. The application elaborated in this article will enhance the ability of researchers to explore and to assess the role of encounter participants TC capabilities and deficiencies in transnational health-care outcomes—including migrant satisfaction/dissatisfaction with provider care, the incorporation of complementary biomedical and ethnocultural health-promotion practices, effective/ineffective migrant-health-promotion behavior in the new environment, and agreement on mental-health needs. The results of conceptually grounded TC research promise to enhance practitioner training and patient education in both North and South.     

Discourse, Power, and the Diagnosis of Weakness: Encountering Practitioners in Bangladesh

The author's experiences as a "patient" of nonbiomedical practitioners, and an examination of Bangladeshis' encounters with practitioners daktars [biomedical doctors], herbalists, exorcists, and diviners), reveal the interactive means by which the diagnosis of durbalata (weakness) is constructed. In the cases presented, facing power in the person of the practitioner means losing face. I argue that discursive phenomena above and below the lexical level are responsible. The phenomena described —(1) interruption or dismissal of the patient1 s words by practitioners and others present during the clinical encounter, (2) divinatory routines that assign the durbalata label to women, and (3) one patient's use of "creaky" voice quality in a strictly "popular sector" (domestic) encounter—are nonreferential but socially significant semiotic processes that operate, for the most part, beneath the level of discursive awareness. These encounters and their outcomes have more to do with social reproduction than with any unambiguously effective therapeutic outcome. [doctor-patient discourse, social construction of illness, language and cognition, semiotics, Bangladesh]     

Risk, Suffering and Competing Narratives in the Psychiatric Assessment of an Iraqi Refugee

This paper highlights the problem of "place" for an Iraqi refugee who, for years, had been tortured and imprisoned in his home country. Specifically, the paper presents a case study of a clinical encounter with this refugee, who had come to the attention of an Australian Crisis Assessment and Treatment Team. Drawing from narrative theory, the paper describes the chaotic nature of the encounter to show how the diverse motives, claims and actions of those present expose the struggle involved in the emplotment of an emerging narrative. The case study is constructed and analysed to illustrate the interpretive machinery of "clinical reasoning" and, in particular, the tension and play between "paradigmatic thinking" and "narrative thinking." More generally, this analysis follows the work of social scientists who seek to expand methodologies for writing about human suffering.     

Head-on encounter rates and walking speed of foragers in leaf-cutting ant traffic

Summary. Trail traffic of the leaf-cutting ant Atta cephalotes involves intermingled flows of outbound and returning foragers. Head-on encounters between workers from the opposite flows are a common occurrence in this traffic. Each encounter momentarily delays the two ants involved, and these small delays might pose a significant cost to the colony's foraging performance when summed over thousands of workers along many metres of trail. We videotaped outbound and returning foragers over a 1 m course, and measured the encounter rates they experienced and their velocity. Our analysis indicates that locomotion speed is diminished by increasing encounter rate, but that the effect is small relative to the effects of ant body size and load mass. Head-on encounters allow exchange of information and leaf fragments between workers, and we consider how the benefits of such encounters may make this form of traffic organization superior to segregated outbound and returning lanes, despite the measurable c ost of encounters in mixed traffic.     

Languages of labor: negotiating the "real" and the relational in Indo-Fijian women's expressions of physical pain

Medical personnel in public clinics in Fiji routinely contend that state-funded medical resources are misallocated on patients who complain of, but do not actually experience, physical pain. Frequently, these patients are identified as being Indo-Fijian women (i.e., women of South Asian origin in Fiji). In this article, I examine clinical interactions between medical staff and female Indo-Fijian patients to demonstrate how "real" and 'unreal' pain are distinguished in the clinical setting and to indicate some of the roles clinical encounters play in community processes that ascribe alternative meanings to physical pain. Focusing on how both physicians and women patients foster certain interpretations of physical pain over others, I argue that the category of 'unreal' pain, as employed by Fiji's physicians, consists of pain that medical professionals consider to be induced by psychological or physical, work-related stresses. I then show how Indo-Fijian women engage in a complementary but distinct discourse that emphasizes links between physical labor and pain and suggests that, in some cases, expressions of physical pain are as much an idiom of pride as an idiom of distress.     

How do high-level specifications of the brain relate to variational approaches?

High-level specification of how the brain represents and categorizes the causes of its sensory input allows to link "what is to be done" (perceptual task) with "how to do it" (neural network calculation). In this article, we describe how the variational framework, which encountered a large success in modeling computer vision tasks, has some interesting relationships, at a mesoscopic scale, with computational neuroscience. We focus on cortical map computations such that "what is to be done" can be represented as a variational approach, i.e., an optimization problem defined over a continuous functional space. In particular, generalizing some existing results, we show how a general variational approach can be solved by an analog neural network with a given architecture and conversely. Numerical experiments are provided as an illustration of this general framework, which is a promising framework for modeling macro-behaviors in computational neuroscience.     

Spatial learning and action planning in a prefrontal cortical network model

The interplay between hippocampus and prefrontal cortex (PFC) is fundamental to spatial cognition. Complementing hippocampal place coding, prefrontal representations provide more abstract and hierarchically organized memories suitable for decision making. We model a prefrontal network mediating distributed information processing for spatial learning and action planning. Specific connectivity and synaptic adaptation principles shape the recurrent dynamics of the network arranged in cortical minicolumns. We show how the PFC columnar organization is suitable for learning sparse topological-metrical representations from redundant hippocampal inputs. The recurrent nature of the network supports multilevel spatial processing, allowing structural features of the environment to be encoded. An activation diffusion mechanism spreads the neural activity through the column population leading to trajectory planning. The model provides a functional framework for interpreting the activity of PFC neurons recorded during navigation tasks. We illustrate the link from single unit activity to behavioral responses. The results suggest plausible neural mechanisms subserving the cognitive "insight" capability originally attributed to rodents by Tolman & Honzik. Our time course analysis of neural responses shows how the interaction between hippocampus and PFC can yield the encoding of manifold information pertinent to spatial planning, including prospective coding and distance-to-goal correlates.     

Host-searching behavior ofVenturia canescens (Grav.) (Hymenoptera: Ichneumonidae): Interference—the effect of mature egg load and prior behavior

The foraging behavior ofVenturia canescens, a solitary endoparasitoid of lepidopteran larvae, was investigated in the laboratory. Females with a greater number of mature eggs in their ovarioles and oviducts parasitized a greater number of hosts and won a greater proportion of encounters with other searching females. Wasps which had been exposed to hosts prior to an experimental trial lost a higher proportion ofagonistic encounters with conspecifics than wasps which had no prior exposure to hosts. The behavior of a wasp at the time of the encounter influenced the outcome of the encounter. Wasps involved in active search of the host medium with the ovipositor (probing) were more likely to win encounters than wasps in any other behavioral category. In a situation where the agonistic encounter was between two probing wasps, both contestants were equally likely to win. Results are discussed in the light of the idea that mutual interference arises, in this species, as a result of agonistic encounters between searching females and recent dynamic-programming models which suggest that parasitoid oviposition should be influenced by mature egg load.     

Effects of encounter in a population of spatial prisoner’s dilemma players

We study the evolution of cooperation in spatial prisoner’s dilemma games, whereby each player extends its interaction scope by trying to interact with a certain number of encounters randomly chosen from its non-neighbors, in addition to its permanently linked nearest neighbors. Furthermore, the non-neighbors treat the initiative interactions in two scenarios: definitely accepting that from the cooperators, whereas guardedly interacting with defectors with an acceptance probability which may take arbitrary value in [0,1]. Importantly, our results reveal that the proposed encounter mechanism is a potent extrinsic factor that is able to boost cooperation when appropriately adjusting the values of the encounter number and acceptance probability, though rational players would always defect in one-shot encounters, regardless of the action from the counterparts. We hope our studies may help understand that the proposed encounter mechanism is also an important ingredient of a flourishing cooperative society.     

Teaching the interrelationship between stress, emotions, and cardiovascular risk using a classic paper by Walter Cannon

Classroom discussion of the classic article by Walter B. Cannon in 1914, entitled "The emergency function of the adrenal medulla in pain and the major emotions," is an excellent tool to teach graduate students the interaction between stress, emotions, and cardiovascular function. Using this article, we are able to review important early research by Dr. Cannon, including discussion of his scientific methods and results and how they hold true today. This article outlines how this classic paper is used to allow students to explore basics principles of cardiovascular control during stress. The teaching points that are presented illustrate how students can be directed to understand the interrelationship between chronic stress and cardiovascular disease.     

Increased Frequency of Intergroup Encounters in Wild Bonobos (<Emphasis Type="Italic">Pan paniscus</Emphasis>) Around the Yearly Peak in Fruit Abundance at Wamba

Intergroup interactions in primates vary from nonagonistic to severely aggressive. Food resources and fertile females cause intergroup aggression when groups defend resources and mates from other groups. Peaceful intermingling during intergroup encounters is rare but has been reported in several primates, including bonobos (Pan paniscus). Although intergroup encounters in bonobos occur at both nonprovisioned and provisioned sites, provisioning may be one factor responsible for frequent intergroup encounters. We studied intergroup encounters between one bonobo group (PE) and its neighboring groups, one semihabituated and two habituated groups, under nonprovisioned conditions in 2010–2015 at Wamba, Democratic Republic of Congo. We examined whether fruit abundance and females with sexual swellings influenced encounter frequency. PE group encountered the other groups on 7.1 days (mean, range: 0–19) per month. Up to four different groups met simultaneously at one location. Encounter frequency was highest around the yearly peak in fruit abundance, suggesting that reduced food competition is linked to increased encounter frequency. During periods of relatively low fruit abundance, the probability of an encounter was higher when a higher number of adult females with maximum sexual swellings were present, suggesting that the attractiveness of females with sexual swellings promoted group encounters during periods of relatively low fruit abundance. These findings suggest that both competition for food and the availability of females with sexual swellings influence encounter frequency in bonobos.     

Communication between Spanish-speaking patients and their doctors in medical encounters

Little research in patient-doctor communication addresses the profound difficulties that emerge as Spanish-speaking patients seek medical services in the U.S. This study examines the interaction of language and culture in medical encounters between Spanish-speaking Latino patients and their doctors who have a range of Spanish language ability and a variety of cultural backgrounds. Initial ethnographic fieldwork investigated Spanish-speaking patients' perceptions of doctors' Spanish language skill as it relates to their medical service. To elaborate on these fieldwork findings, medical encounters were audiotaped for detailed conversational analysis. Data from the two methods illustrate how language and culture interact in accomplishing communicative tasks as doctors attend Spanish-speaking patients.The author would like to express appreciation to the reviewers for the thoughtful detail of their comments on the original version of this paper.     

Imaging emotional brain functions: Conceptual and methodological issues

This article reviews the psychophysiological and brain imaging literature on emotional brain function from a methodological point of view. The difficulties in defining, operationalising and measuring emotional activation and, in particular, aversive learning will be considered. Emotion is a response of the organism during an episode of major significance and involves physiological activation, motivational, perceptual, evaluative and learning processes, motor expression, action tendencies and monitoring/subjective feelings. Despite the advances in assessing the physiological correlates of emotional perception and learning processes, a critical appraisal shows that functional neuroimaging approaches encounter methodological difficulties regarding measurement precision (e.g., response scaling and reproducibility) and validity (e.g., response specificity, generalisation to other paradigms, subjects or settings). Since emotional processes are not only the result of localised but also of widely distributed activation, a more representative model of assessment is needed that systematically relates the hierarchy of high- and low-level emotion constructs with the corresponding patterns of activity and functional connectivity of the brain.     

Effects of social group size on information transfer and task allocation

Summary Social animals exchange information during social interaction. The rate of interaction and, hence, the rate of information exchange, typically changes with density and density may be affected by the size of the social group. We investigate models in which each individual may be engaged in one of several tasks. For example, the different tasks could represent alternative foraging locations exploited by an ant colony. An individual's decision about which task to pursue depends both on environmental stimuli and on interactions among individuals. We examine how group size affects the allocation of individuals among the various tasks. Analysis of the models shows the following. (1) Simple interactions among individuals with limited ability to process information can lead to group behaviour that closely approximates the predictions of evolutionary optimality models, (2) Because per capita rates of social interaction may increase with group size, larger groups may be more efficient than smaller ones at tracking a changing environment, (3) Group behaviour is determined both by each individual's interaction with environmental stimuli and by social exchange of information. To keep these processes in balance across a range of group sizes, organisms are predicted to regulate per capita rates of social interaction and (4) Stochastic models show, at least in some cases, that the results described here occur even in small groups of approximately ten individuals.     

Pluralism and pragmatism: knowledge and practice of birth in Morocco

This article examines knowledge and practice surrounding birth in Morocco, using women's narratives of their recent birth experiences, observations of medical encounters, and statements about prescribed behaviors during pregnancy and birth, as well as the vocabulary used to refer to physiological processes, disease conditions, and social relationships. The analysis shows that the three major themes that define the traditional Moroccan ethnophysiology of birth--conceptions of hot and cold, the symbolism of blood, and the metaphors of openness and obstruction--are not inconsistent with the precepts of biomedicine and public health and do not in themselves constitute obstacles either to safe home births or the use of formal health services. Women integrate biomedical and local knowledge and practices and simultaneously seek care from "traditional" and "modern" practitioners, creatively combining elements in accordance with their situations and the means at their disposal. Birth narratives show the eclecticism and flexibility that characterize women's attitudes and behaviors regarding pregnancy and birth. Women's decisions are shaped by two overriding considerations: incertitude about what can happen during the last phase of a pregnancy and ambivalence toward the available alternatives for care, both of which reflect a realistic assessment of their situations. By showing how women make decisions in response to these considerations, this article seeks to clarify some of the links between beliefs and practices and to contribute to ongoing discussions regarding the relevance of local knowledge for patterns of health care.     

Reproduction and heredity beliefs of the Hindus based on their sacred books

Hindus see their children as the reincarnation of the husband. The mother is only a field where the father lays his seed. That the reincarnated husband might be a girl is explained by a more abundant female "semen." Differences among children are explained by the influence of the mother, the same way as a seedling is affected by the soil in which it grows. Because a son is generally desired, one can find in the sacred books of India rules that might increase the chances not only to have a son, but a healthy and gifted one.