1000 resultados para Enemy as a System


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Tutkielman tavoitteena oli analysoida Air-Sea Battle -konseptia ja sen lähtökohtana ollutta viholliskuvaa John Wardenin Enemy as a System -teorian näkökulmasta julkisten asiakirjojen, raporttien ja artikkeleiden avulla. Tutkimusmenetelmänä on käytetty teoriaohjaavaa sisällönanalyysia. Tutkimusongelmaksi muodostui: ”Miten Air-Sea Battle -konsepti näyttäytyy Wardenin Enemy as a System -teorian näkökulmasta?” Tutkimuskysymyksien avulla pyrittiin lisäksi löytämään konseptin kehittämiseen johtaneita tekijöitä suurstrategisella tasolla, arvioimaan konseptin mukaista aseellisen voiman käyttöä sekä analysoimaan konseptia suhteessa Wardenin näkemyksiin sotilasstrategiasta. Wardenin Enemy as a System -teoria on esitelty tutkielman alkupuolella hyödyntäen alkuperäistekstejä, aiheesta kirjoitettuja tutkimuksia ja artikkeleita sekä sotataidollista kirjallisuutta. Air-Sea Battle -konseptia käsittelevän luvun aineisto on luokiteltu Wardenin neljän strategisen kysymyksen teemojen, eli tavoitteen, vaikuttamisen kohteiden, keinojen ja irtautumisen, mukaisesti. Tärkeimmät lähteet varsinaisen Air-Sea Battle -asiakirjan lisäksi olivat Yhdysvaltojen turvallisuus- ja sotilasstrategiaa määrittelevät dokumentit, tutkimuslaitosten julkaisemat raportit sekä aikakauslehtiartikkelit. Aineiston perusteella Yhdysvallat näkee tiettyjen valtioiden, kuten Kiinan, kehittyvät niin kutsutut anti-access/area denial -suorituskyvyt uhkana alueelliselle tasapainolle ja heidän kyvylleen ylläpitää sotilaallista läsnäoloa strategisesti merkittävillä alueilla. Air-Sea le -konseptin tavoitteena on määritellä ja kehittää suorituskyvyt, operatiiviset suunnitelmat ja toimintamallit, joiden mukaan toimivalla joukolla kyetään luomaan riittävä pelotevaikutus konfliktin ehkäisemiseksi tai säilyttämään toiminnanvapaus alueella sen muodostuessa.

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Emergency Departments (EDs) and Emergency Rooms (ERs) are designed to manage trauma, respond to disasters, and serve as the initial care for those with serious illnesses. However, because of many factors, the ED has become the doorway to the hospital and a “catch-all net” for patients including those with non-urgent needs. This increase in the population in the ED has lead to an increase in wait times for patients. It has been well documented that there has been a constant and consistent rise in the number of patients that frequent the ED (National Center for Health Statistics, 2002); the wait time for patients in the ED has increased (Pitts, Niska, Xu, & Burt, 2008); and the cost of the treatment in the ER has risen (Everett Clinic, 2008). Because the ED was designed to treat patients who need quick diagnoses and may be in potential life-threatening circumstances, management of time can be the ultimate enemy. If a system was implemented to decrease wait times in the ED, decrease the use of ED resources, and decrease costs endured by patients seeking care, better outcomes for patients and patient satisfaction could be achieved. The goal of this research was to explore potential changes and/or alternatives to relieve the burden endured by the ED. In order to explore these options, data was collected by conducting one-on-one interviews with seven physicians closely tied to a Level 1 ED (Emergency Room physicians, Trauma Surgeons and Primary Care physicians). A qualitative analysis was performed on the responses of one-on-one interviews with the aforementioned physicians. The interviews were standardized, open-ended questions that probe what makes an effective ED, possible solutions to improving patient care in the ED, potential remedies for the mounting problems that plague the ED, and the feasibility of bringing Primary Care Physicians to the ED to decrease the wait times experienced by the patient. From the responses, it is clear that there needs to be more research in this area, several areas need to be addressed, and a variety of solutions could be implemented. The most viable option seems to be making the ED its own entity (similar to the clinic or hospital) that includes urgent clinics as a part of the system, in which triage and better staffing would be the most integral part of its success.^

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In this study, we used data from both experiments and mathematical simulations to analyze the consequences of the interacting effects of intraguild predation (IGP), cannibalism and parasitism occurring in isolation and simultaneously in trophic interactions involving two blowfly species under shared parasitism. We conducted experiments to determine the short-term response of two blowfly species to these interactions with respect to their persistence. A mathematical model was employed to extend the results obtained from these experiments to the long-term consequences of these interactions for the persistence of the blowfly species. Our experimental results revealed that IGP attenuated the strength of the effects of cannibalism and parasitism between blowfly host species, increasing the probability of persistence of both populations. The simulations obtained from the mathematical model indicated that IGP is a key interaction for the long-term dynamics of this system. The presence of different species interacting in a tri-trophic system relaxed the severity of the effects of a particular interaction between two species, changing species abundances and promoting persistence through time. This pattern was related to indirect interactions with a third species, the parasitoid species included in this study. © 2012 The Society of Population Ecology and Springer Japan.

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1. Intra-specific variation in plant defence traits has been shown to profoundly affect herbivore community structure. Here we describe two experiments designed to test whether similar effects occur at higher trophic levels, by studying pea aphid–natural enemy interactions in a disused pasture in southern England. 2. In the first experiment, the numbers and identity of natural enemies attacking different monoclonal pea aphid colonies were recorded in a series of assays throughout the period of pea aphid activity. 3. In the summer assay, there was a significant effect of clone on the numbers of aphidophagous hoverfly larvae and the total number of non-hoverfly natural enemies recruited. Clone also appeared to influence the attack rate suffered by the primary predator in the system, the hoverfly Episyrphus balteatus, by Diplazon laetatorius, an ichneumonid parasitoid. Colonies were generally driven to extinction by hoverfly attack, resulting in the recording of low numbers of parasitoids and entomopathogens, suggesting intense intra-guild predation. 4. To further examine the influence of clonal variation on the recruitment of natural enemies, a second experiment was performed to monitor the temporal dynamics of community development. Colonies were destructively sampled every other day and the numbers of natural enemies attacking aphid colonies were recorded. These data demonstrated that clonal variation influenced the timing, abundance, and identity of natural enemies attacking aphid colonies. 5. Taken together, these data suggest that clonal variation may have a significant influence on the patterns of interactions between aphids and their natural enemies, and that such effects are likely to affect our understanding of the ecology and biological control of these insect herbivores.

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Organic agriculture is becoming widespread due to increased consumer demand and regulatory and political support. Organic agriculture can increase arthropod diversity but the response of pests and their natural enemies is variable. Fertiliser is an important component of agricultural systems and its effects on pests and natural enemies will influence agroecosystems. In this study, meta-analysis and vote-counting techniques were used to compare farming system (organic and conventional) and fertiliser effects on arthropod pests and their natural enemies. The meta-analyses indicated that pests generally benefitted from organic techniques, this is particularly evident when experiments were carried out on a smaller scale. Pest responses to organic and conventional fertiliser types were divergent, plant composts benefitted pest arthropods while the opposite was true for manures, this has implications for pest management. Most natural enemy groups responded positively to organic farming although this was not true for Coleopterans. Experimental scale had a prominent impact on natural enemy responses with farm scale studies showing particularly positive effects of organic agriculture on natural enemies. This suggests that it is large scale features of organic agriculture such as landscape heterogeneity that are beneficial to natural enemies. Natural enemy responses to organic fertilisers were positive indicating that field scale management practices including fertiliser can also be important in pest management.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Despite its appeal to explain plant invasions, the enemy release hypothesis (ERH) remains largely unexplored for tropical forest trees. Even scarcer are ERH studies conducted on the same host species at both the community and biogeographical scale, irrespective of the system or plant life form. In Cabrits National Park, Dominica, we observed patterns consistent with enemy release of two introduced, congeneric mahogany species, Swietenia macrophylla and S. mahagoni, planted almost 50 years ago. Swietenia populations at Cabrits have reproduced, with S. macrophylla juveniles established in and out of plantation areas at densities much higher than observed in its native range. Swietenia macrophylla juveniles also experienced significantly lower leaf-level herbivory (~3.0%) than nine co-occurring species native to Dominica (8.4–21.8%), and far lower than conspecific herbivory observed in its native range (11%–43%, on average). These complimentary findings at multiple scales support ERH, and confirm that Swietenia has naturalized at Cabrits. However, Swietenia abundance was positively correlated with native plant diversity at the seedling stage, and only marginally negatively correlated with native plant abundance for stems ≥1-cm dbh. Taken together, these descriptive patterns point to relaxed enemy pressure from specialized enemies, specifically the defoliator Steniscadia poliophaea and the shoot-borer Hypsipyla grandella, as a leading explanation for the enhanced recruitment of Swietenia trees documented at Cabrits.

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Partial migration, in which a fraction of a population migrate and the rest remain resident, occurs in an extensive range of species and can have powerful ecological consequences. The question of what drives differences in individual migratory tendency is a contentious one. It has been shown that the timing of partial migration is based upon a trade-off between seasonal fluctuations in predation risk and growth potential. Phenotypic variation in either individual predation risk or growth potential should thus mediate the strength of the trade-off and ultimately predict patterns of partial migration at the individual level (i.e. which individuals migrate and which remain resident). We provide cross-population empirical support for the importance of one component of this model—individual predation risk—in predicting partial migration in wild populations of bream Abramis brama, a freshwater fish. Smaller, high-risk individuals migrate with a higher probability than larger, low-risk individuals, and we suggest that predation risk maintains size-dependent partial migration in this system.

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Paul Weisengrün

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One hypothesis for the success of invasive species is reduced pathogen burden, resulting from a release from infections or high immunological fitness (low immunopathology) of invaders. Despite of strong selection exerted on the host, the evolutionary response of invaders to newly acquired pathogens has rarely been considered. The two independent and genetically distinct invasions of the Pacific oyster Crassostrea gigas into the North Sea represent an ideal model system to study fast evolutionary responses of invasive populations. By exposing both invasion sources to ubiquitous and phylogenetically diverse pathogens (Vibrio spp.) we demonstrate that within a few generations hosts adapted to sympatric pathogen communities. However, this local adaptation only became apparent in selective environments, i.e. at elevated temperatures reflecting patterns of disease outbreaks in natural populations. Resistance against sympatric and allopatric Vibrio spp. strains was dominantly inherited in crosses between both invasion sources, resulting in an overall higher resistance of admixed individuals than pure lines. Therefore we suggest that a simple genetic resistance mechanism of the host is matched to a common virulence mechanism shared by local Vibrio strains. This combination might have facilitated a fast evolutionary response that can explain another dimension of why invasive species can be so successful in newly invaded ranges.

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Territorial individuals often respond less aggressively to intrusions by their neighbours than to intrusions by unfamiliar individuals. This commonly observed strategy, the dear-enemy phenomenon, is thought to minimise the costs associated with territory defence. This study determined whether an insular population of territory-holding buff-banded rails (Gallirallus philippensis) exhibits dear-enemy relationships and whether males and females differ in their responses to neighbours and non-neighbours. Playback techniques were used to examine and compare the vocalisations and movements of focal individuals in response to the territorial advertisement calls of their neighbours and of unfamiliar individuals (non-neighbours). Results showed that focal birds did not respond differently to the calls of neighbours and non-neighbours; thus, no evidence for the dear-enemy phenomenon was found in this species. We suggest that this result is due to the significant threats posed by neighbours to territory owners in this territorial system, in addition to a high level of territorial instability in the population. Males and females were shown to differ qualitatively in their general territorial response to intruders but not in their relative responses to neighbours and non-neighbours, suggesting that the relative threats posed by neighbours and non-neighbours do not differ between the sexes.

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Bone marrow is organized in specialized microenvironments known as 'marrow niches'. These are important for the maintenance of stem cells and their hematopoietic progenitors whose homeostasis also depends on other cell types present in the tissue. Extrinsic factors, such as infection and inflammatory states, may affect this system by causing cytokine dysregulation (imbalance in cytokine production) and changes in cell proliferation and self-renewal rates, and may also induce changes in the metabolism and cell cycle. Known to relate to chronic inflammation, obesity is responsible for systemic changes that are best studied in the cardiovascular system. Little is known regarding the changes in the hematopoietic system induced by the inflammatory state carried by obesity or the cell and molecular mechanisms involved. The understanding of the biological behavior of hematopoietic stem cells under obesity-induced chronic inflammation could help elucidate the pathophysiological mechanisms involved in other inflammatory processes, such as neoplastic diseases and bone marrow failure syndromes.

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To compare time and risk to biochemical recurrence (BR) after radical prostatectomy of two chronologically different groups of patients using the standard and the modified Gleason system (MGS). Cohort 1 comprised biopsies of 197 patients graded according to the standard Gleason system (SGS) in the period 1997/2004, and cohort 2, 176 biopsies graded according to the modified system in the period 2005/2011. Time to BR was analyzed with the Kaplan-Meier product-limit analysis and prediction of shorter time to recurrence using univariate and multivariate Cox proportional hazards model. Patients in cohort 2 reflected time-related changes: striking increase in clinical stage T1c, systematic use of extended biopsies, and lower percentage of total length of cancer in millimeter in all cores. The MGS used in cohort 2 showed fewer biopsies with Gleason score ≤ 6 and more biopsies of the intermediate Gleason score 7. Time to BR using the Kaplan-Meier curves showed statistical significance using the MGS in cohort 2, but not the SGS in cohort 1. Only the MGS predicted shorter time to BR on univariate analysis and on multivariate analysis was an independent predictor. The results favor that the 2005 International Society of Urological Pathology modified system is a refinement of the Gleason grading and valuable for contemporary clinical practice.