326 research outputs found

    Detecting (non)parallel evolution in multidimensional spaces: angles, correlations and eigenanalysis.

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    Parallelism between evolutionary trajectories in a trait space is often seen as evidence for repeatability of phenotypic evolution, and angles between trajectories play a pivotal role in the analysis of parallelism. However, properties of angles in multidimensional spaces have not been widely appreciated by biologists. To remedy this situation, this study provides a brief overview on geometric and statistical aspects of angles in multidimensional spaces. Under the null hypothesis that trajectory vectors have no preferred directions (i.e. uniform distribution on hypersphere), the angle between two independent vectors is concentrated around the right angle, with a more pronounced peak in a higher-dimensional space. This probability distribution is closely related to t- and beta distributions, which can be used for testing the null hypothesis concerning a pair of trajectories. A recently proposed method with eigenanalysis of a vector correlation matrix can be connected to the test of no correlation or concentration of multiple vectors, for which simple test procedures are available in the statistical literature. Concentration of vectors can also be examined by tools of directional statistics such as the Rayleigh test. These frameworks provide biologists with baselines to make statistically justified inferences for (non)parallel evolution

    Ontogenetic change of morphology and surface texture of long bones in the Gray Heron (Ardea cinerea, Ardeidae)

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    Proceedings of the 8th International Meeting of the Society of Avian Paleontology and EvolutionAlthough the importance of assessing ontogenetic age or developmental stage of fossil materials is widely recognized, information on avian postnatal skeletal ontogeny, which forms a basis for ageing criteria for bird fossils, is seriously lacking. One potentially useful ontogenetic ageing method in avian paleontology is textural ageing, in which surface textures of long bones are examined to assess developmental stage. To date, ontogenetic change of surface textures in long bones has been intensively described in only one species, the Canada Goose (Branta canadensis). In this study, through original preparation and examination of an ontogenetic series of specimens, which consists of 13 chicks (including one fledgling), two juveniles (birds under one-yearold) and two adults, postnatal ontogenetic changes of macroscopic morphology and surface texture of six major long bones (humerus, ulna, carpometacarpus, femur, tibiotarsus and tarsometatarsus) of the Gray Heron (Ardea cinerea, Ardeidae) are described and illustrated. Most long bones continue to grow in length until reaching their adult size range around the time of fledging. Epiphyses are generally not ossified before fledging; in both ends of femur and proximal end of tibiotarsus, distinct ossification centers can be observed. Generally, long bones of chicks are characterized by rough surface textures, including striated structures near epiphyses and fibrous/ porous surface with frequent penetrating pits in the midshaft. Long bones of juveniles are characterized by faint grooves and/or dimples, but rough striated structure may remain in the proximal regions of tibiotarsus and tarsometatarsus. In adults smooth surface pattern dominates. Inter-elemental variation in surface texture in one species is likely to represent taxon-specific patterns of relative timings of maturity among long bones, which would be related to various aspects of skeletal ontogeny in birds. At this time, textural ageing on birds with interrupted growth might be somewhat problematic because of a lack of sufficient data

    Wing Musculature Reconstruction in Extinct Flightless Auks (<i>Pinguinus</i> and <i>Mancalla</i>) Reveals Incomplete Convergence with Penguins (Spheniscidae) Due to Differing Ancestral States.

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    Despite longstanding interest in convergent evolution, factors that result in deviations from fully convergent phenotypes remain poorly understood. In birds, the evolution of flightless wing-propelled diving has emerged as a classic example of convergence, having arisen in disparate lineages including penguins (Sphenisciformes) and auks (Pan-Alcidae, Charadriiformes). Nevertheless, little is known about the functional anatomy of the wings of flightless auks because all such taxa are extinct, and their morphology is almost exclusively represented by skeletal remains. Here, in order to re-evaluate the extent of evolutionary convergence among flightless wing-propelled divers, wing muscles and ligaments were reconstructed in two extinct flightless auks, representing independent transitions to flightlessness: Pinguinus impennis (a crown-group alcid), and Mancalla (a stem-group alcid). Extensive anatomical data were gathered from dissections of 12 species of extant charadriiforms and 4 aequornithine waterbirds including a penguin. The results suggest that the wings of both flightless auk taxa were characterized by an increased mechanical advantage of wing elevator/retractor muscles, and decreased mobility of distal wing joints, both of which are likely advantageous for wing-propelled diving and parallel similar functional specializations in penguins. However, the conformations of individual muscles and ligaments underlying these specializations differ markedly between penguins and flightless auks, instead resembling those in each respective group's close relatives. Thus, the wings of these flightless wing-propelled divers can be described as convergent as overall functional units, but are incompletely convergent at lower levels of anatomical organization-a result of retaining differing conditions from each group's respective volant ancestors. Detailed investigations such as this one may indicate that, even in the face of similar functional demands, courses of phenotypic evolution are dictated to an important degree by ancestral starting points

    New Approach Combining Branch and Price with Metaheuristics to Solve Nurse Scheduling Problem

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    This paper presents a new approach combining Branch and Price (B&P) with metaheuristics to derive various high-quality schedules as solutions to a nurse scheduling problem (nurse rostering problem). There are two main features of our approach. The first is the combination of B&P and metaheuristics, and the second is the implementation of an efficient B&P algorithm. Through applying our approach to widely used benchmark instances, the effectiveness of our approach is determined

    The relationship between involuntarily retrieved positive autobiographical memory and implicit mood

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    Previous studies have reported that positive autobiographical memories are involuntarily retrieved on a daily basis and often accompany mood changes. Previous studies have used subjective report methods to measure the impact of involuntary retrieval on mood. However, subjective report methods are known to be easily distorted by social desirability and demand characteristics. To avoid this problem, we applied the measurement of implicit mood and examined the impact of involuntary positive memory on mood. Sixty-four participants participated in the experiment and 48 participants were included in the analyses. Participants carried out an easy task in which the retrieval cue was presented, to induce an involuntary positive memory. Participants were also asked to rate the mood of nonsense words in order to measure implicit mood before and after the task. The results demonstrated that the involuntary positive memory retrieval increased positive mood in participants who exhibited lower positive implicit mood before the involuntary memory retrieval. We experimentally demonstrated that involuntarily retrieved positive memories can improve implicit mood

    Lymphopenia at diagnosis predicts survival of patients with immunodeficiency-associated lymphoproliferative disorders

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    The number of patients who are administered immunosuppressive agents has been increasing. Accordingly, more patients face higher risks for developing immunodeficiency-associated lymphoproliferative disorders (LPD). Although immunodeficiency-associated LPD are distinct from other lymphoid neoplasms in terms of their immunocompromised backgrounds, little is known about the impact of lymphopenia at diagnosis on survival in patients with these LPD. Seventy-one immunodeficiency-associated LPD in Kyoto University Hospital (post-transplant LPD (PTLD), n = 26; other iatrogenic immunodeficiency-associated LPD, n = 45) were reviewed and analyzed. The median age at diagnosis was 63 years (range, 3–83). Diffuse large B cell lymphoma was the most common subtype (n = 33), followed by Hodgkin lymphoma (n = 12), B cell monomorphic LPD not specified (n = 11), and polymorphic LPD or early-phase diseases (n = 15). The median follow-up period for survivors was 2.5 years and overall survival (OS) and progression-free survival (PFS) at 2.5 years were 75% and 67%, respectively. Multivariate analysis showed that lymphopenia (≤ 800/μL) at diagnosis predicted inferior OS (HR, 3.72; P = 0.043) and PFS (HR, 3.82; P = 0.012). Serum albumin values also strongly affected OS (> 3.18 g/dL vs. ≤ 3.18 g/dL; HR, 0.21; P = 0.010) and PFS (HR, 0.26; P = 0.013). Lymphopenia at diagnosis is suggested to predict inferior OS and PFS in patients with immunodeficiency-associated LPDs. Immunocompromised status might affect disease progression in these distinct lymphoid neoplasms growing under immunocompromised backgrounds

    Crossmodal correspondences between visual features and tastes in preschoolers: an exploratory study

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    IntroductionAdults possess a natural inclination to associate sensory cues derived from distinct modalities, such as the pairing of sweet with pink. However, studies exploring crossmodal correspondences in children, particularly in the sensory pairing of visual features and tastes, are scant, leaving unanswered questions regarding the developmental trajectory of crossmodal correspondences. The present study investigates whether Japanese preschool children demonstrate specific biases in shape–color, shape–taste, and color–taste associations.MethodsIn a series of in-person experiments, 92 children between 3 to 6 years of age completed matching tasks utilizing paper stimuli.ResultsChildren exhibit crossmodal correspondences in shape-color (circle-red and asymmetrical star-yellow), shape–taste (triangle-salty and circle-sweet), and color–taste (yellow-sour, black-bitter, and pink-sweet) associations. Moreover, children’s choices are not influenced by their individual preferences.DiscussionThe crossmodal correspondences observed in this study have been observed in previous research on adults from the same (Japanese) culture, although adults showed more crossmodal correspondences than the children in this study (e.g., pink-circle, triangle-sour, and green-bitter). Thus, while some crossmodal correspondences emerge during childhood, others may require additional time to develop, thereby highlighting the importance of understanding the cognitive mechanisms underlying crossmodal correspondences from an ontogenic perspective

    The lectin‐like domain of thrombomodulin is a drug candidate for both prophylaxis and treatment of liver ischemia and reperfusion injury in mice

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    Ischemia and reperfusion injury (IRI) can occur in any tissue or organ. With respect to liver transplantation, the liver grafts from donors by definition experience transient ischemia and subsequent blood reflow. IRI is a problem not only in organ transplantation but also in cases of thrombosis or circulatory disorders such as mesenteric ischemia, myocardial, or cerebral infarction. We have reported that recombinant human soluble thrombomodulin (rTM), which is currently used in Japan to treat disseminated intravascular coagulation (DIC), has a protective effect and suppresses liver IRI in mice. However, rTM may not be fully safe to use in humans because of its inherent anticoagulant activity. In the present study, we used a mouse liver IRI model to explore the possibility that the isolated lectin-like domain of rTM (rTMD1), which has no anticoagulant activity, could be effective as a therapeutic modality for IRI. Our results indicated that rTMD1 could suppress ischemia and reperfusion-induced liver damage in a dose-dependent manner without concern of associated hemorrhage. Surprisingly, rTMD1 suppressed the liver damage even after IR insult had occurred. Taken together, we conclude that rTMD1 may be a candidate drug for prevention of and therapy for human liver IRI without the possible risk of hemorrhage

    Predictive importance of left ventricular myocardial stiffness for the prognosis of patients with congestive heart failure

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    SummaryObjectivesThis study was designed to determine the prognostic importance of left ventricular (LV) myocardial stiffness, a hemodynamic index which is closely related to B-type natriuretic peptide (BNP) concentration in patients with congestive heart failure (CHF).BackgroundWhile elevated BNP, an abnormality of cardiac neurohormones, is known to be an independent marker of death or re-admission, it remains to be clarified whether there is also a strong predictor directly related to cardiac dysfunction.MethodsLV performance variables and stress–strain analyses including diastolic myocardial stiffness constant (Km) were obtained from 37 patients with initial CHF by the combined simultaneous measurement of echocardiographic and hemodynamic data. Survivors were monitored for a mean of 23 months, with the main endpoint being combined death or first re-admission for CHF.ResultsTen patients (27%) were primary endpoint cases. Both Km and plasma BNP levels were higher in the event than in the event-free group. By Cox proportional hazards analysis, Km≥4.0 was identified as the only variable with significant and independently incremental predictive power to affect the primary endpoint (adjusted hazard ratio=7.354, 95% confidence interval 1.379–39.232, p=0.02).ConclusionsIn patients with CHF, increased myocardial stiffness may have greater prognostic significance compared to other conventional predictors. Increased myocardial stiffness may be considered to be an important prognostic factor independent of the loading conditions
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