140 research outputs found
Can Preference for Oviposition Sites Initiate Reproductive Isolation in Callosobruchus maculatus?
Theory has identified a variety of evolutionary processes that may lead to speciation. Our study includes selection experiments using different host plants and test key predictions concerning models of speciation based on host plant choice, such as the evolution of host use (preference and performance) and assortative mating. This study shows that after only ten generations of selection on different resources/hosts in allopatry, strains of the seed beetle Callosobruchus maculatus develop new resource preferences and show resource-dependent assortative mating when given the possibility to choose mates and resources during secondary contact. The resulting reduced gene flow between the different strains remained for two generations after contact before being overrun by disassortative mating. We show that reduced gene flow can evolve in a population due to a link between host preference and assortative mating, although this result was not found in all lines. However, consistent with models of speciation, assortative mating alone is not sufficient to maintain reproductive isolation when individuals disperse freely between hosts. We conclude that the evolution of reproductive isolation in this system cannot proceed without selection against hybrids. Other possible factors facilitating the evolution of isolation would be longer periods of allopatry, the build up of local adaptation or reduced migration upon secondary contact
Інтертекстуальна деміургія: спроба порівняльного аналізу оповідання Дж. Р. Р. Толкієна "Листок Ніггля" та роману М.Булгакова «Майстер і Маргарита»
(uk) Одним з найяскравіших прикладав інтертекстуального творення є роман М. Булгакова «Майстер та Маргарита». Ця стаття є спробою порівняльного аналізу твору російського письменника і казки Дж. Толкієна «Листок Ніггла», найповніше простежуються особливості деміургійного процесу. Дж. Толкієн у короткій казці оповідає долю генія, в алегоричній формі розкриває його (генія) здібності до створення та перетворення світу.(en) The article is devoted to the comparative analysis of J. Tolkien's and M. Bulgakov's creative conception that is mostly embodied in the works «Leaf by Niggle» and «Master and Margaret». The main character of the tale «Leaf by Niggle» resembles other J. Tolkien's heroes and the author himself. The tale is devoted to the fate of a genius, opens his abilities for creation and transformation o f the world
Miért hagytuk?: Szemelvények az elmúlt 25 évben született írásaimból
1990 óta mintegy 130 tanulmányt (köztük több könyvet) írtam a területi kormányzásról, jórészt a hazai önkormányzati rendszert fókuszba állítva, tehát van és volt mondanivalóm a kérdéskörben. Nem azért választottam a szemelvényes műfajt, korábbi írásaim ból válogatva, mert egyszerűbb és gyorsabb megoldásnak tűnt, nem beszélve az önfényezés kézenfekvő lehetőségéről, hanem azért, mert azt szeretném szemléltetni, hogy a szakma (jelentős része) kezdetektől fogva tisztában volt az önkormányzati rendszer előnyeivel és hátrányaival, s egyben képes is volt arra, hogy javaslatokat fogalmazzon meg a megoldásokra. Hogy 25 év alatt miért jártuk be a teljes decentralizációtól a szinte totális centralizációig terjedő göröngyös és nem is egyirányú utat, az sokkal inkább magyarázható a hazai politikai elit érdekei és értékei felől, illetve a reformdöntések körülményeivel. Ebben az évben záruló OTKA kutatásunk 1 reményeim szerint evidenciákkal alátámasztva igazolja ezt a feltételezést. Az összeállítás talán arra is alkalmas, hogy értékeljük a kormányzati reformokban a szakértői tudás szerepét
PENGEMBANGAN MODEL PEMBELAJARAN EVALUASI PENDIDIKAN DAN AUTENTIK ASSESMEN BERBASIS KEBUN SEKOLAH UNTUK MENGEMBANGKAN KEMAMPUAN BERPIKIR KRITIS DAN KARAKTER MAHASISWA PGSD
Global climate change is expected to have major effects on host-parasite dynamics, with potentially enormous consequences for entire ecosystems. To develop an accurate prognostic framework, theoretical models must be supported by empirical research. We investigated potential changes in host-parasite dynamics between a fish parasite, the eyefluke Diplostomum baeri, and an intermediate host, the European perch Perca fluviatilis, in a large-scale semi-enclosed area in the Baltic Sea, the Biotest Lake, which since 1980 receives heated water from a nuclear power plant. Two sample screenings, in two consecutive years, showed that fish from the warmer Biotest Lake were now less parasitized than fish from the Baltic Sea. These results are contrasting previous screenings performed six years after the temperature change, which showed the inverse situation. An experimental infection, by which perch from both populations were exposed to D. baeri from the Baltic Sea, revealed that perch from the Baltic Sea were successfully infected, while Biotest fish were not. These findings suggest that the elevated temperature may have resulted, among other outcomes, in an extremely rapid evolutionary change through which fish from the experimental Biotest Lake have gained resistance to the parasite. Our results confirm the need to account for both rapid evolutionary adaptation and biotic interactions in predictive models, and highlight the importance of empirical research in order to validate future projections
Mediterranean mesocarnivores in spatially structured managed landscapes : community organisation in time and space
During the final stage of the study GCS was funded by a doctoral grant from FCT (PD/BD/114037/2015). TAM thanks support by CEAUL (funded by FCT project – UID/MAT/00006/2013).In the multi-functional and biodiverse cork oak landscapes of Iberia (Montado), agro-silvo-pastoral practices promote landscape heterogeneity and create intricate habitat and resource availability patterns. We used camera-traps to investigate the temporal and spatial organisation of a mesocarnivore community in a Montado landscape in central Portugal. The target carnivore assemblage was largely dominated by three generalist species – the red fox Vulpes vulpes, the European badger Meles meles and the Egyptian mongoose Herpestes ichneumon – while remaining community members – the common genet Genetta genetta and the feral cat Felis silvestris spp. – exhibited restricted distributions. Interspecific differences in activity rhythms and habitat use were particularly marked among widespread species. Low temporal overlap was reported between the diurnal mongoose and predominantly nocturnal red fox and badger. For the latter two species, contrasting differences in habitat use were associated with anthropogenic-induced environmental heterogeneity. Whereas the red fox used more intensively Montado areas preserving dense shrubby understory and avoided semi-disturbed mosaics of sparse shrubs, the badgers displayed the opposite pattern. Our findings add to previous evidence suggesting that the spatial structure created in highly managed landscapes, particularly the diversity of resulting understory structures, promotes the abundance and spread of generalist mesocarnivore species. These may benefit from the surplus of resource amount (e.g. prey) and the creation of different human-made habitats conditions that provide particular combinations of ecological resources favourable to each species requirements. We concur the common view that maintaining understory heterogeneity in Montado landscapes, menaced by current intensification and extensification trends, is important where carnivore persistence is a relevant conservation goal, but alert for potential effects on carnivore assemblages structuring and impacts for specialist species less tolerant to disturbance.PostprintPeer reviewe
PREDICTIVE AND DISCRIMINATIVE VALUE OF SHOULDER PROPRIOCEPTION TESTS FOR PATIENTS WITH WHIPLASH-ASSOCIATED DISORDERS
Jämförelser mellan metoder för fastvolymbestämning av stockar
In 2008 a new method for automatic measurement of solid volume under bark (m3sub) of sawlogs was introduced in southern Sweden. In this method the diameters at 10 cm intervals are used, thus producing a section-wise volume (m3sub-sw). The scanners used are programmed to leave out bumps and indents when diameters are calculated. The objective of the study was to compare this method with two other methods used on the Swedish wood market; a) volume based on top and butt end diameters (m3sub-tb) and b) volume based on top end diameters and conversion factors to solid volume (m3sub-cf). The conversion factors are arranged as a matrix based on diameter and length of the logs. Volume m3sub-tb is the most widely used method for measuring m3sub in Sweden. M3sub-cf is partly used for payment but more widely for planning purposes, for example when the logs are priced as a cylinder volume based on top end diameter.
The study was performed on spruce (Picea abies). The three different volume estimates as well as the diameters obtained from the log scanners were evaluated on 435 manually measured control logs from five different mills. For an additional 180 000 automatically measured logs from four of the sawmills the m3sub-sw and m3sub-cf volume estimates were compared.
The results showed only minor differences between the methods. The volume m3sub-sw was, for the 180 000 logs, 0.6 % greater than the volume m3sub-cf. The analysis of the matrix for conversion factors showed that, if the matrix was to be revised, this should be done as slightly increased factors for small diameter logs and for big diameter logs. However, it was concluded that it would mean less implications for the wood market if the section-wise volume could be reduced to make this volume equal to m3sub-tb and m3sub-cf. This to achieve that all three methods, given a sufficient number of representative logs, would give the same volum
Leptin Affects Life History Decisions in a Passerine Bird: A Field Experiment
BACKGROUND: Organisms face trade-offs regarding their life-history strategies, such as decisions of single or multiple broods within a year. In passerines displaying facultative multiple breeding, the probability of laying a second clutch is influenced by several life-history factors. However, information about the mechanistic background of these trade-offs is largely lacking. Leptin is a protein hormone produced by white fat cells, and acts as a signal between peripheral energy depots and the central nervous system. In addition, leptin affects cells at all levels of the reproductive axis and plays a critical role in regulating the allocation of metabolic energy to reproduction. As such, it is possible that leptin levels influence the decision of whether or not to invest time and energy into a second clutch. Accordingly, we expect a treatment with exogenous leptin to result in an increased number of second broods. METHODOLOGY/PRINCIPAL FINDINGS: At a later stage during the first brood, female great tits were treated either with long-term leptin-filled cholesterol pellets (the experimental birds) or with pellets containing only cholesterol (the control birds). We found that leptin-treated females were significantly more likely to have a second brood and that the earlier females were more likely to lay a second clutch than the late females. CONCLUSIONS/SIGNIFICANCE: As both timing of first brood and treatment with leptin were important in the decision of having multiple broods, the trade-offs involved in the breeding strategy most likely depend on multiple factors. Presumably leptin has evolved as a signal of energy supply status to regulate the release of reproductive hormones so that reproduction is coordinated with periods of sufficient nutrients. This study investigated the role of leptin as a mediator between energy resources and reproductive output, providing a fundamentally new insight into how trade-offs work on a functional basis
How well do questionnaires on symptoms in neck-shoulder disorders capture the experiences of those who suffer from neck-shoulder disorders? A content analysis of questionnaires and interviews
<p>Abstract</p> <p>Background</p> <p>Previous research has indicated neck-shoulder disorders to have a fluctuating course incorporating a variety of symptoms. These findings awoke our interest to make a comparison between symptoms experienced by people affected with the disorder and the content of questionnaires that assess pain and other symptoms in neck-shoulder disorders. Thus the aims of this study were: -to explore the symptoms experienced by people with non-specific neck-shoulder problems, as well as experiences of nuances and temporal variations (fluctuations) of symptoms; -to investigate which sources were used in the development of ten questionnaires for assessing pain and other symptoms in the neck-shoulder; -to analyse the item content of the questionnaires; -to analyse the correspondence between the item content of the questionnaires and the symptoms described by the informants.</p> <p>Methods</p> <p>Content analysis of interviews with 40 people with non-specific neck-shoulder pain, and 10 questionnaires used to assess pain and other symptoms in neck-shoulder disorders.</p> <p>Results</p> <p>The interviews revealed a variety of symptoms indicating a bodily, mental/cognitive, and emotional engagement, and more general and severe symptoms than are usually considered in neck-shoulder questionnaires. Taking all questionnaires together many of the symptoms were considered, but most questionnaires only included a few of them. The informants were able to distinguish fluctuation of symptoms, and a variety of different qualities which were not usually considered in the questionnaires. Only two questionnaires had made use of the opinions of affected people in the development.</p> <p>Conclusion</p> <p>Few of the questionnaires had made use of the experiences of affected people in the development. The correspondence between the symptoms expressed by those affected and the content of the questionnaires was low. A variety of symptoms were expressed by the interviewees, and the participants were also able to distinguish nuances and fluctuations of symptoms. The present study points to the importance of other aspects than just pain and physical functioning as clinical trial outcome measures related to neck-shoulder disorders. To develop a condition-specific questionnaire, it is important to decide on the specific symptoms for the condition. Using the experiences of those affected, in combination with relevant research and professional knowledge, can enhance the validity of the questionnaires.</p
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