Balancing the dilution and oddity effects: Decisions depend on body size

Background Grouping behaviour, common across the animal kingdom, is known to reduce an individual's risk of predation; particularly through dilution of individual risk and predator confusion (predator inability to single out an individual for attack). Theory predicts greater risk of predation to individuals more conspicuous to predators by difference in appearance from the group (the ‘oddity’ effect). Thus, animals should choose group mates close in appearance to themselves (eg. similar size), whilst also choosing a large group. Methodology and Principal Findings We used the Trinidadian guppy (Poecilia reticulata), a well known model species of group-living freshwater fish, in a series of binary choice trials investigating the outcome of conflict between preferences for large and phenotypically matched groups along a predation risk gradient. We found body-size dependent differences in the resultant social decisions. Large fish preferred shoaling with size-matched individuals, while small fish demonstrated no preference. There was a trend towards reduced preferences for the matched shoal under increased predation risk. Small fish were more active than large fish, moving between shoals more frequently. Activity levels increased as predation risk decreased. We found no effect of unmatched shoal size on preferences or activity. Conclusions and Significance Our results suggest that predation risk and individual body size act together to influence shoaling decisions. Oddity was more important for large than small fish, reducing in importance at higher predation risks. Dilution was potentially of limited importance at these shoal sizes. Activity levels may relate to how much sampling of each shoal was needed by the test fish during decision making. Predation pressure may select for better decision makers to survive to larger size, or that older, larger fish have learned to make shoaling decisions more efficiently, and this, combined with their size relative to shoal-mates, and attractiveness as prey items influences shoaling decisions

Modulation of host cell processes by T3SS effectors

Two of the enteric Escherichia coli pathotypes-enteropathogenic E. coli (EPEC) and enterohaemorrhagic E. coli (EHEC)-have a conserved type 3 secretion system which is essential for virulence. The T3SS is used to translocate between 25 and 50 bacterial proteins directly into the host cytosol where they manipulate a variety of host cell processes to establish a successful infection. In this chapter, we discuss effectors from EPEC/EHEC in the context of the host proteins and processes that they target-the actin cytoskeleton, small guanosine triphosphatases and innate immune signalling pathways that regulate inflammation and cell death. Many of these translocated proteins have been extensively characterised, which has helped obtain insights into the mechanisms of pathogenesis of these bacteria and also understand the host pathways they target in more detail. With increasing knowledge of the positive and negative regulation of host signalling pathways by different effectors, a future challenge is to investigate how the specific effector repertoire of each strain cooperates over the course of an infection

Man and the Last Great Wilderness: Human Impact on the Deep Sea

The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life – SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO2 and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO2 and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods

Astrocytes: biology and pathology

Astrocytes are specialized glial cells that outnumber neurons by over fivefold. They contiguously tile the entire central nervous system (CNS) and exert many essential complex functions in the healthy CNS. Astrocytes respond to all forms of CNS insults through a process referred to as reactive astrogliosis, which has become a pathological hallmark of CNS structural lesions. Substantial progress has been made recently in determining functions and mechanisms of reactive astrogliosis and in identifying roles of astrocytes in CNS disorders and pathologies. A vast molecular arsenal at the disposal of reactive astrocytes is being defined. Transgenic mouse models are dissecting specific aspects of reactive astrocytosis and glial scar formation in vivo. Astrocyte involvement in specific clinicopathological entities is being defined. It is now clear that reactive astrogliosis is not a simple all-or-none phenomenon but is a finely gradated continuum of changes that occur in context-dependent manners regulated by specific signaling events. These changes range from reversible alterations in gene expression and cell hypertrophy with preservation of cellular domains and tissue structure, to long-lasting scar formation with rearrangement of tissue structure. Increasing evidence points towards the potential of reactive astrogliosis to play either primary or contributing roles in CNS disorders via loss of normal astrocyte functions or gain of abnormal effects. This article reviews (1) astrocyte functions in healthy CNS, (2) mechanisms and functions of reactive astrogliosis and glial scar formation, and (3) ways in which reactive astrocytes may cause or contribute to specific CNS disorders and lesions

Henkilöstötilinpäätös osana pörssiyhtiön henkilöstöraportointia : case: Palveluyritys Oy

Opinnäytetyön aiheena on henkilöstötilinpäätös. Opinnäytetyön tavoitteena on luoda malli case-yrityksen ensimmäiselle henkilöstötilinpäätökselle, jota voidaan myöhemmin hyödyntää myös koko konsernissa. Tavoitteena on myös kartoittaa henkilöstötietojärjestelmien tuottaman informaation hyödyntämismahdollisuuksia sekä tuoda esiin ne seikat, jotka vielä kaipaavat kehittämistä henkilöstöinformaation tuottamiseksi. Opinnäytetyössä tarkastellaan myös pörssiyhtiöiltä vaadittavaa henkilöstöinformaation tuottamista, sillä case-yritys tulee mahdollisesti tulevaisuudessa listautumaan Helsingin pörssiin. Teoriaosuuden lähdeaineistossa on hyödynnetty sekä kirjallista materiaalia että internetiin pohjautuvia artikkeleita. Työn empiirinen osuus perustuu henkilöstötietojärjestelmien tuottaman informaation analysointiin. Tutkimus on luonteeltaan kvantitatiivinen, jolloin henkilöstöä tarkastellaan numeeristen tietojen avulla. Empiirisessä osuudessa henkilöstön ominaisuuksia lähestytään myös graafein ja taulukoin. Empiirisen osuuden henkilöstöä kuvaavat mittarit on valittu niiden asioiden perusteella, joiden seurannan yhtiön johto on kokenut tarpeelliseksi. Tilastot ja tunnusluvut perustuvat jo olemassa oleviin tietoihin, minkä vuoksi koko henkilöstön kattavia taulukoita ei voitu tietojen puutteellisuuden vuoksi laatia. Opinnäytetyössä tarkastellaan tilikautta 1.1.–31.12.2007, mutta osa tiedoista on tilastoitu tämän jälkeiseltä ajalta. Tietojen hyödyntäminen on perusteltua siitäkin syystä, että tutkimuksen tavoitteena on kartoittaa nykyisiä raportointimahdollisuuksia sekä luoda kehitysehdotuksia henkilöstöinformaation vaivattomampaan tuottamiseen. Tutkimuksen keskeisenä tuloksena voidaan todeta, että case-yrityksen henkilöstöinformaatiojärjestelmien pohjalta pystytään nykyistäkin kattavammin hyödyntämään henkilöstöstä saatavaa tietoa. Osa seurantajärjestelmien kehityksestä on kuitenkin vielä työn alla. Järjestelmiin perustuva informaatio on vielä vajanaista, minkä vuoksi henkilöstön tilasta ei vielä voida saada täysin luotettavaa kuvaa järjestelmien tuottaman informaation avulla.This thesis focuses on the human resource statement. The aim of the study was to create a model for an enterprise’s first human resource statement. In the future this model will be used in the entire corporation. The study was completed with two goals in mind. The first goal was to explore the opportunities of utilising a personnel information system. The second goal was to bring forward issues that still need development in producing personnel information. The personnel information requried from a public limited company was also examined in this study. Sources for the theoretical part of this study included literatury material and the Internet. The empirical part of the thesis is based on the analysis of information from a personnel information system. A quantitative method was utilised in this study. This means that information relating to the personnel is described with numerical information, graphics and tables. The representational indicators of the personnel, in the empirical section, have been chosen based on factors that the case company management has experienced as useful. Statistics and key figures have been collected from already existing information. However, due to the lack of information statistics representing the entire personnel have not been possible to compile. Although this study focuses on the accounting period January 1 – December 31, 2007, some information was still compiled after this period. The reason behind the use of statistics gathered after the accounting period lies in the aim of this study. This thesis explores the possibilities of current personnel reporting and creates development proposals for easier personnel information production. The study shows that the case company can comprehensively use the diversity of the information with the current personnel information system. However, a part of the monitoring system is still under development. Thus, the information received, based on the existing system, is incomplete. And, because the present system does not include the entire personnel of the case company, a reliable picture of the personnel situation is not possible