952 resultados para Because I tell a joke or two
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Background and Aims Male-biased sex allocation commonly occurs in wind-pollinated hermaphroditic plants, and is often positively associated with size, notably in terms of height. Currently, it is not well established whether a corresponding pattern holds for dioecious plants: do males of wind-pollinated species exhibit greater reproductive allocation than females? Here, sexual dimorphism is investigated in terms of life history trade-offs in a dioecious population of the wind-pollinated ruderal herb Mercurialis annua.Methods The allocation strategies of males and females grown under different soil nutrient availability and competitive (i.e. no, male or female competitor) regimes were compared.Key Results Male reproductive allocation increased disproportionately with biomass, and was greater than that of females when grown in rich soils. Sexual morphs differentially adjusted their reproductive allocation in response to local environmental conditions. In particular, males reduced their reproductive allocation in poor soils, whereas females increased theirs, especially when competing with another female rather than growing alone. Finally, males displayed smaller above-ground vegetative sizes than females, but neither nutrient availability nor competition had a strong independent effect on relative size disparities between the sexes.Conclusions Selection appears to favour plasticity in reproductive allocation in dioecious M. annua, thereby maintaining a relatively constant size hierarchy between sexual morphs. In common with other dioecious species, there seems to be little divergence in the niches occupied by males and females of M. annua.
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This thesis studies gray-level distance transforms, particularly the Distance Transform on Curved Space (DTOCS). The transform is produced by calculating distances on a gray-level surface. The DTOCS is improved by definingmore accurate local distances, and developing a faster transformation algorithm. The Optimal DTOCS enhances the locally Euclidean Weighted DTOCS (WDTOCS) with local distance coefficients, which minimize the maximum error from the Euclideandistance in the image plane, and produce more accurate global distance values.Convergence properties of the traditional mask operation, or sequential localtransformation, and the ordered propagation approach are analyzed, and compared to the new efficient priority pixel queue algorithm. The Route DTOCS algorithmdeveloped in this work can be used to find and visualize shortest routes between two points, or two point sets, along a varying height surface. In a digital image, there can be several paths sharing the same minimal length, and the Route DTOCS visualizes them all. A single optimal path can be extracted from the route set using a simple backtracking algorithm. A new extension of the priority pixel queue algorithm produces the nearest neighbor transform, or Voronoi or Dirichlet tessellation, simultaneously with the distance map. The transformation divides the image into regions so that each pixel belongs to the region surrounding the reference point, which is nearest according to the distance definition used. Applications and application ideas for the DTOCS and its extensions are presented, including obstacle avoidance, image compression and surface roughness evaluation.
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Clonally reproducing hemicryptophytic rosette plants are common in the alpine belt. However, their demography, and indirectly their growth and reproductive strategy in these harsh conditions, was rarely studied. We analysed the morphology, clonal reproduction and demography of one such species, Leontopodium alpinum, in two populations of the Swiss Alps. The species forms small colonies of 1-5 (maximum 30) sterile rosettes with a few flowering stalks. After flowering, the apical meristem dies and one or two new axillary buds grow below the previous rosette in the following year, developing into short rhizomes (<2 cm), which decay after four years. The new stalk produces sterile rosettes before flowering after two to four years, depending on climatic conditions. The apical meristem often dies during the sterile stage, and is replaced by a new axillary bud. Levkovitch matrices on two stages (sterile and flowering rosettes) showed that rosette survival and clonal reproduction maintain long-lived populations (λ = 0.96). Elasticities indicated that a change in the survival of sterile rosettes had the strongest effect on population dynamics, and this stage lasts, on average, 6.8 years at 2480 m. Altogether, L. alpinum is following Tomlinson's architectural model. This growth form appears perfectly adapted to harsh alpine conditions: the clonal ramification ensures longevity to genets and the semelparous behaviour of the rosettes allows an efficient flowering, whatever the climatic conditions. L. alpinum appears to follow a common growth model among rosette possessing hemicryptophytes in the alpine belt.
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Renal osteodystrophy is an amalgam of a number of distinct pathological conditions, in particular, hyperparathyroidism and osteomalacia. In addition, there may be a change in the guantity of bone, i.e., osteopenia (osteoporosis) or osteosclerosis. While bone biopsy may be the most reliable method for detecting these lesions, it is not yet a routine procedure in many centers. Radiological assessment of the bones, therefore, is the most widely used method for assessing the type and severity of the bone lesions in patients with chronic renal failure. This article reviews the world literature and pays attention to conventional radiological techniques as well as macroradiography. In addition, studies in which radiological appearances are correlated with histological appearances are described. Mention is also made of the effects on radiological bone disease of dialysis and transplantation. Consideration is also given to the manifestations of soft-tissue calcification, both of the vascular and subcutaneous type, and to the effects of treatment.
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This book comprises two volumes and builds on the findings of the DISMEVAL project (Developing and validating DISease Management EVALuation methods for European health care systems), funded under the European Union's (EU) Seventh Framework Programme (FP7) (Agreement no. 223277). DISMEVAL was a three-year European collaborative project conducted between 2009 and 2011. It contributed to developing new research methods and generating the evidence base to inform decision-making in the field of chronic disease management evaluation (www.dismeval.eu). In this book, we report on the findings of the project's first phase, capturing the diverse range of contexts in which new approaches to chronic care are being implemented and evaluating the outcomes of these initiatives using an explicit comparative approach and a unified assessment framework. In this first volume, we describe the range of approaches to chronic care adopted in 12 European countries. By reflecting on the facilitators and barriers to implementation, we aim to provide policy-makers and practitioners with a portfolio of options to advance chronic care approaches in a given policy context.
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The topographical distribution of sciatic and femoral nerve sensory neuronal somata in the L4 dorsal root ganglion of the adult rat was mapped after retrograde tracing with one or two of the dyes Fast Blue, Fluoro-Gold, or Diamidino Yellow. The tracers were applied to the proximal transected end of either nerve alone, or from both nerves in the same animal using separate tracers. Three-dimensional reconstructions of the distribution of labelled neurones were made from serial sections of the L4 dorsal root ganglion which is the only ganglion that these two nerves share. The results showed that with little overlap, femoral nerve neurones distribute dorsally and rostrally whereas sciatic nerve neurones distribute medially and ventrally. This finding indicates the existence of a somatotopical organisation for the representation of different peripheral nerves in dorsal root ganglia of adult animals.
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Language extinction as a consequence of language shifts is a widespread social phenomenon that affects several million people all over the world today. An important task for social sciences research should therefore be to gain an understanding of language shifts, especially as a way of forecasting the extinction or survival of threatened languages, i.e., determining whether or not the subordinate language will survive in communities with a dominant and a subordinate language. In general, modeling is usually a very difficult task in the social sciences, particularly when it comes to forecasting the values of variables. However, the cellular automata theory can help us overcome this traditional difficulty. The purpose of this article is to investigate language shifts in the speech behavior of individuals using the methodology of the cellular automata theory. The findings on the dynamics of social impacts in the field of social psychology and the empirical data from language surveys on the use of Catalan in Valencia allowed us to define a cellular automaton and carry out a set of simulations using that automaton. The simulation results highlighted the key factors in the progression or reversal of a language shift and the use of these factors allowed us to forecast the future of a threatened language in a bilingual community.
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Research suggests that employees sometimes retaliate and sometimes refrain from retaliation for the same reason, namely because they care about justice. In two studies, we seek to solve this apparent inconsistency. Drawing on just world theory, we argue that retaliatory, harmful behavioral strategies to deal with injustice are associated to individual differences in personal belief in a just world (personal BJW). In contrast, individual differences in believing that the world is just in general (general BJW) are linked to the inhibition of these reactions. As a consequence, the relation between injustice and harmful behaviors is stronger for people with a high personal BJW than for those with a low one. General BJW is associated with their inhibition such that the relation between injustice and harmful reactions is weaker for people with a high general BJW than for those with a low one. We found evidence for our hypotheses in a cross-sectional field study and an experiment. We discuss our findings in light of their implications for just-world theory and suggest avenues for future research integrating organizational justice literature.
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Tämän tutkimuksen tavoitteena on rakentaa kannattavuuden simulointimalli, joka tukee Laminating Papers Oy:n Kotkan impregnointitehtaan johtoa optimaalisen tuotemixin, konelinjan ja työaikamuodon valintaan liittyvässä päätöksenteossa. Tutkimus on tapaustutkimus ja aineiston analyysitapa on kvalitatiivinen. Kohdeyrityksen mallin rakentamista lähestytään tuote- ja asiakaskannattavuuden sekä kustannusten mallintamisen teorian kautta. Pelkkä tuloslaskelma ei kerro tuote- ja asiakaskohtaisesta kannattavuudesta, minkä vuoksi johdon päätöksenteon tueksi tarvitaan erillisiä järjestelmiä ja malleja. Kustannusten mallintamisen myötä saatavaa informaatiota voidaan käyttää sekä operatiivisessa että strategisessa päätöksenteossa. Hyvän mallin aikaan saamiseksi mallintamisessa on tärkeää noudattaa järjestelmällisyyttä sekä huomioida johdon tarpeet, mallin tavoitteet ja kaikki kannattavuuden muodostumiseen vaikuttavat oleelliset tekijät.
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To investigate whether caveolin-1 (cav-1) may modulate inducible nitric oxide synthase (iNOS) function in intact cells, the human intestinal carcinoma cell lines HT29 and DLD1 that have low endogenous cav-1 levels were transfected with cav-1 cDNA. In nontransfected cells, iNOS mRNA and protein levels were increased by the addition of a mix of cytokines. Ectopic expression of cav-1 in both cell lines correlated with significantly decreased iNOS activity and protein levels. This effect was linked to a posttranscriptional mechanism involving enhanced iNOS protein degradation by the proteasome pathway, because (i) induction of iNOS mRNA by cytokines was not affected and (ii) iNOS protein levels increased in the presence of the proteasome inhibitors N-acetyl-Leu-Leu-Norleucinal and lactacystin. In addition, a small amount of iNOS was found to cofractionate with cav-1 in Triton X-100-insoluble membrane fractions where also iNOS degradation was apparent. As has been described for endothelial and neuronal NOS isoenzymes, direct binding between cav-1 and human iNOS was detected in vitro. Taken together, these results suggest that cav-1 promotes iNOS presence in detergent-insoluble membrane fractions and degradation there via the proteasome pathway.
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Genome duplications increase genetic diversity and may facilitate the evolution of gene subfunctions. Little attention, however, has focused on the evolutionary impact of lineage-specific gene loss. Here, we show that identifying lineage-specific gene loss after genome duplication is important for understanding the evolution of gene subfunctions in surviving paralogs and for improving functional connectivity among human and model organism genomes. We examine the general principles of gene loss following duplication, coupled with expression analysis of the retinaldehyde dehydrogenase Aldh1a gene family during retinoic acid signaling in eye development as a case study. Humans have three ALDH1A genes, but teleosts have just one or two. We used comparative genomics and conserved syntenies to identify loss of ohnologs (paralogs derived from genome duplication) and to clarify uncertain phylogenies. Analysis showed that Aldh1a1 and Aldh1a2 form a clade that is sister to Aldh1a3-related genes. Genome comparisons showed secondarily loss of aldh1a1 in teleosts, revealing that Aldh1a1 is not a tetrapod innovation and that aldh1a3 was recently lost in medaka, making it the first known vertebrate with a single aldh1a gene. Interestingly, results revealed asymmetric distribution of surviving ohnologs between co-orthologous teleost chromosome segments, suggesting that local genome architecture can influence ohnolog survival. We propose a model that reconstructs the chromosomal history of the Aldh1a family in the ancestral vertebrate genome, coupled with the evolution of gene functions in surviving Aldh1a ohnologs after R1, R2, and R3 genome duplications. Results provide evidence for early subfunctionalization and late subfunction-partitioning and suggest a mechanistic model based on altered regulation leading to heterochronic gene expression to explain the acquisition or modification of subfunctions by surviving ohnologs that preserve unaltered ancestral developmental programs in the face of gene loss.
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The use of the Bayes factor (BF) or likelihood ratio as a metric to assess the probative value of forensic traces is largely supported by operational standards and recommendations in different forensic disciplines. However, the progress towards more widespread consensus about foundational principles is still fragile as it raises new problems about which views differ. It is not uncommon e.g. to encounter scientists who feel the need to compute the probability distribution of a given expression of evidential value (i.e. a BF), or to place intervals or significance probabilities on such a quantity. The article here presents arguments to show that such views involve a misconception of principles and abuse of language. The conclusion of the discussion is that, in a given case at hand, forensic scientists ought to offer to a court of justice a given single value for the BF, rather than an expression based on a distribution over a range of values.
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Typically, conflicts in world environmental negotiations are related, amongst other aspects, to the level of polarization of the countries in groups with conflicting interests. Given the predictable relationship between polarization and conflict, it would seem logical to evaluate the degree to which the distribution of countries – for example, in terms of their CO2 emissions per capita – would be structured through groups which in themselves are antagonistic, as well as their evolution over time. This paper takes the concept of polarization to explore this distribution for the period 1992-2010, looking at different analytic approaches related to the concept. Specifically, it makes a comparative evaluation of the results associated with endogenous multi-polarization measures (i.e. EGR and DER indices), exogenous measures (i.e. Z-K or multidimensional index) and strict bipolarization measures (i.e. Wolfson’s measure). Indeed, the interest lies not only in evaluating the global situation of polarization by comparing the different approaches and their temporal patterns, but also in examining the explanatory capacity of the different proxy groups used as a possible reference for designing global environmental policy from a group premise. JEL codes: D39; Q43; Q56. Key words: polarization; carbon emissions; conflict;
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Interbreeding of two species in the wild implies introgression of alleles from one species into the other only when admixed individuals survive and successfully backcross with the parental species. Consequently, estimating the proportion of first generation hybrids in a population may not inform about the evolutionary impact of hybridization. Samples obtained over a long time span may offer a more accurate view of the spreading of introgressed alleles in a species" gene pool. Common quail (Coturnix coturnix) populations in Europe have been restocked extensively with farm quails of hybrid origin (crosses with Japanese quails, C. japonica). We genetically monitored a common quail population over 15 years to investigate whether genetic introgression is occurring and used simulations to investigate our power to detect it. Our results revealed that some introgression has occurred, but we did not observe a significant increase over time in the proportion of admixed individuals. However, simulations showed that the degree of admixture may be larger than anticipated due to the limited power of analyses over a short time span, and that observed data was compatible with a low rate of introgression, probably resulting from reduced fitness of admixed individuals. Simulations predicted this could result in extensive admixture in the near future.
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Hamstring muscle injuries and tendon disorders are common, especially in sports. They can be severe and difficult to treat, often resulting in impaired athletic performance and long rehabilitation times. Previous studies considering treatment of these problems are scarce. The current study was designed to investigate the effect of surgery on different types of hamstring muscle injuries and on proximal hamstring tendinopathy. In addition, we wanted to study the typical histopathological findings relating to proximal hamstring tendinopathy. In the study of complete (all three muscles torn) proximal hamstring avulsions (41 patients), our results showed that early operative treatment gives significantly better results than late surgery, and is therefore recommended. Despite this, considerable improvement of symptoms could also be achieved in chronic cases. In the study of partial (one or two muscles torn) proximal hamstring tears (47 patients), we observed that these injuries can cause significant functional deficit and impaired performance in athletes. The main finding was that after surgical repair most of the patients were able to return to their pre-injury level of sports. In the study of distal hamstring tears (18 patients), the results showed that surgical treatment had a good effect in the majority of these cases. In proximal hamstring tendinopathy, the main problem is pain which limits sports. In this study (90 patients), we found that after unsuccessful conservative treatment, surgery was a good treatment option resulting in full return to sports in most cases. In tendinopathic hamstring tendons, the morphological changes of tendinosis were largely identical to those previously described in other common (e.g. Achilles and patellar) tendinopathies. In chronic proximal hamstring avulsions, and also in reoperations, a large defect between distally retracted tendons and the ischial tuberosity may occasionally prevent anatomic reinsertion. We have described a reconstruction method using fascia lata autograft augmentation to be used in these most challenging repairs. This technique was utilized in the treatment of five patients, with encouraging results.