177 research outputs found

    Evidence from the Special Relativity and Blackbody Radiation Theories for the Existence of Photons Possessing Zero Kinetic Energy

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    The traditional interpretation of radiative emission and absorption asserts that photons are created and annihilated in such processes. A Gedanken experiment is considered in which kinetic energy from observed photons is systematically removed until a limit of zero is reached. With the help of the relativistic Doppler effect it is shown that even for infinitesimally small kinetic energies the photons continue to exist, since in other inertial systems they will be observed to have a much higher energy/frequency falling in an easily detectable range. It is possible to formulate an alternative explanation for absorption and emission processes on this basis in terms of real photons with exactly zero kinetic energy being present before or after radiative interactions. Bolstering this hypothesis is the fact that the statistical mechanical treatment of photons interacting with oscillators in blackbody radiation theory predicts an infinite density of photons of this energy, both in the original Planck formulation employing Maxwell-Boltzmann statistics and in the subsequent Bose-Einstein description. These considerations demonstrate that the E = 0 state is greatly preferred as the product of absorption because of the requirement to have the interaction occur in a relatively narrow region of space- time. There is thus strong evidence that photons are not created and annihilated in radiative processes but simply have their kinetic energy changed either to or from a zero value. Accordingly a very high density of zero-energy photons is expected to exist uniformly throughout the universe. Finally, this development suggests that one should subject the creation-annihilation hypothesis to careful scrutiny in other areas of physics as well.Comment: 26 pages, 2 figure

    Super star clusters and Supernovae in interacting LIRGs unmasked by NIR adaptive optics

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    We report on an on-going near-IR adaptive optics survey targeting interacting luminous IR galaxies. High-spatial resolution NIR data are crucial to enable interpretation of kinematic, dynamical and star formation (SF) properties of these very dusty objects. Whole progenitor nuclei in the interactions can be missed if only optical HST imaging is used. Here we specifically present the latest results regarding core-collapse supernovae found within the highly extincted nuclear regions of these galaxies. Direct detection and study of such highly obscured CCSNe is crucial for revising the optically-derived SN rates used for providing an independent measurement of the SF history of the Universe. We also present thus-far the first NIR luminosity functions of super star cluster (SSC) candidates. The LFs can then be used to constrain the formation and evolution of SSCs via constraints based on initial mass functions and cluster disruption models.Comment: 6 pages. To appear in proceedings of 'Galaxies and their Masks' (Namibia, April 2010), published by Springer, New York, eds. D.L. Block, K.C. Freeman, I. Puerar

    The impact of tooth colour on the perceptions of age and social judgements.

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    ObjectivePsychological research has established that the presence of dental anomalies negatively impact social judgements. This study sought to determine the effects of tooth colour on the subjective ratings of social judgements in a group of Caucasian adults.MethodsA cross sectional experimental analogue design comprised fifty Caucasian adults: 25 women and 25 men. A total of 54 digitally modified photographs of Caucasian males and females (darkened, natural, whitened teeth) were evaluated. All participants evaluated each of the images on 12 characteristics: popularity, friendliness, social life, success, graduation, happiness, intelligence, perceived age, introversion/extraversion, self-confidence, attractiveness and satisfaction with the tooth shade. Analysis of variance (ANOVA) was used to compare ratings.ResultsParticipants associated darkened teeth with poorer subjective ratings, with the highest ratings been given to whitened teeth, and natural teeth being intermediate. These trends were similar across all participant age groups and gender. Further, the gender and age groups of the images had a significant effect on the appraisals. Faces of younger models received higher ratings than the faces of older models and female images were rated higher than the males.ConclusionIn the absence of other information, tooth colour exerts an influence upon the appraisals made in social situations. It appears that whitened tooth appearance is preferred to natural tooth appearance, irrespective of age and gender of the judge. The faces with more whitened dentition are perceived to be younger across all age groups and gender of the judges. Participants dissatisfied with their own tooth shade drew out more stereotypic behaviour.Clinical significance statementThis research used standardised tooth colour as a basis to investigate perceived age and social functioning. As clinicians face daily challenges to achieve patient satisfaction with respect to dental aesthetics, standardizing the colour may enhance the patients’ satisfaction. Further, participants dissatisfied with their own tooth shade drew out more stereotypic behaviour. The whitened dentition may impair the psychological well-being of the individuals and is probably a reason for the increasing demand for cosmetic dental procedures. These results may be instructive for the development of a psycho-educational intervention to prevent any unrealistic expectations.</p

    Life path analysis: scaling indicates priming effects of social and habitat factors on dispersal distances

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    1. Movements of many animals along a life-path can be separated into repetitive ones within home ranges and transitions between home ranges. We sought relationships of social and environmental factors with initiation and distance of transition movements in 114 buzzards Buteo buteo that were marked as nestlings with long-life radio tags. 2. Ex-natal dispersal movements of 51 buzzards in autumn were longer than for 30 later in their first year and than 35 extra-natal movements between home ranges after leaving nest areas. In the second and third springs, distances moved from winter focal points by birds that paired were the same or less than for unpaired birds. No post-nuptial movement exceeded 2 km. 3. Initiation of early ex-natal dispersal was enhanced by presence of many sibs, but also by lack of worm-rich loam soils. Distances travelled were greatest for birds from small broods and with relatively little short grass-feeding habitat near the nest. Later movements were generally enhanced by the absence of loam soils and short grassland, especially with abundance of other buzzards and probable poor feeding habitats (heathland, long grass). 4. Buzzards tended to persist in their first autumn where arable land was abundant, but subsequently showed a strong tendency to move from this habitat. 5. Factors that acted most strongly in ½-km buffers round nests, or round subsequent focal points, usually promoted movement compared with factors acting at a larger scale. Strong relationships between movement distances and environmental characteristics in ½-km buffers, especially during early ex-natal dispersal, suggested that buzzards became primed by these factors to travel far. 6. Movements were also farthest for buzzards that had already moved far from their natal nests, perhaps reflecting genetic predisposition, long-term priming or poor habitat beyond the study area

    Antihypertensive adherence and outcomes among community-dwelling Medicare beneficiaries: the Atherosclerosis Risk in Communities Study

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    Rationale, aims, and objectives: Despite proven benefits for reducing incidence of major cardiac events, antihypertensive drug therapy remains underutilized in the United States. This analysis assesses antihypertensive drug adherence, utilization predictors, and associations between adherence and outcomes (a composite of cardiovascular events, Medicare inpatient payments, and inpatient days). Methods: The sample consisted of Atherosclerosis Risk in Communities Study cohort participants reporting hypertension without prevalent cardiovascular disease during 2006 to 2007 annual follow-up calls. Atherosclerosis Risk in Communities records were linked to Medicare claims through 2012. Antihypertensive medication adherence was measured as more than 80% proportion days covered by using Medicare Part D claims. Standard and hierarchical regression models were used to evaluate adjusted associations between person characteristics and adherence and between adherence and outcomes. Results: Among 1826 hypertensive participants with Part D coverage, 31.5% had no antihypertensive class with more than 80% proportion days covered in the 3 months preceding the report of hypertension in 2006 to 2007. After adjustment for confounders, positive predictors of use included female gender and diabetes; negative predictors were African-American race and current smoking. Adjusted association between receiving no therapy and a composite endpoint of cardiovascular outcomes through 2012 was not statistically significant (hazard ratio: 0.93; 95% confidence interval: 0.72, 1.22) nor was the adjusted association with Medicare inpatient days or payments (incremental difference at 48 months in payments: 1217;951217; 95% CI: −2030, $4463). Conclusions: Despite having medical and prescription coverage, nearly a third of hypertensive participants were not adherent to antihypertensive drug therapy. Differences in clinical outcomes associated with nonadherence, though not statistically significant, were consistent with results from randomized trials. The approach provides a model framework for rigorous assessment of detailed data that are increasingly available through emerging sources

    Genetic variants and blood pressure in a population-based cohort: the cardiovascular risk in young Finns study

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    Clinical relevance of a genetic predisposition to elevated blood pressure was quantified during the transition from childhood to adulthood in a population-based Finnish cohort (N=2,357). Blood pressure was measured at baseline in 1980 (age 3–18 years) and in follow-ups in 1983, 1986, 2001 and 2007. Thirteen single nucleotide polymorphisms associated with blood pressure were genotyped and three genetic risk scores associated with systolic and diastolic blood pressure and their combination were derived for all participants. Effects of the genetic risk score were 0.47 mmHg for systolic and 0.53 mmHg for diastolic blood pressure (both p<0.01). The combination genetic risk score was associated with diastolic blood pressure from age 9 onwards (β=0.68 mmHg, p=0.015). Replications in 1194 participants of the Bogalusa Heart Study showed essentially similar results. The participants in the highest quintile of the combination genetic risk score had a 1.82-fold risk of hypertension in adulthood (p<0.0001) compared with the lowest quintile, independent of a family history of premature hypertension. These findings show that genetic variants are associated with preclinical blood pressure traits in childhood, individuals with several susceptibility alleles have on average a 0.5 mmHg higher blood pressure and this trajectory continues from childhood to adulthood

    Time Evolution of Unstable Particle Decay Seen with Finite Resolution

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    Time evolution of the decay process of unstable particles is investigated in field theory models. We first formulate how to renormalize the non-decay amplitude beyond perturbation theory and then discuss short-time behavior of very long-lived particles. Two different formalisms, one that does and one that does not, assume existence of the asymptotic field of unstable particles are considered. The non-decay amplitude is then calculated by introducing a finite time resolution of measurement, which makes it possible to discuss both renormalizable and non-renormalizable decay interaction including the nucleon decay. In ordinary circumstances the onset of the exponential decay law starts at times as early as at roughly the resolution time, but with an enhanced amplitude which may be measurable. It is confirmed that the short-time formula 1Γt1 - \Gamma t of the exponential decay law may be used to set limits on the nucleon decay rate in underground experiments. On the other hand, an exceptional example of S-wave decay of very small Q-value is found, which does not have the exponential period at all.Comment: 26 pages, LATEX file with 8 PS figure

    MultiCellDS : a community-developed standard for curating microenvironment-dependent multicellular data

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    Exchanging and understanding scientific data and their context represents a significant barrier to advancing research, especially with respect to information siloing. Maintaining information provenance and providing data curation and quality control help overcome common concerns and barriers to the effective sharing of scientific data. To address these problems in and the unique challenges of multicellular systems, we assembled a panel composed of investigators from several disciplines to create the MultiCellular Data Standard (MultiCellDS) with a use-case driven development process. The standard includes (1) digital cell lines, which are analogous to traditional biological cell lines, to record metadata, cellular microenvironment, and cellular phenotype variables of a biological cell line, (2) digital snapshots to consistently record simulation, experimental, and clinical data for multicellular systems, and (3) collections that can logically group digital cell lines and snapshots. We have created a MultiCellular DataBase (MultiCellDB) to store digital snapshots and the 200+ digital cell lines we have generated. MultiCellDS, by having a fixed standard, enables discoverability, extensibility, maintainability, searchability, and sustainability of data, creating biological applicability and clinical utility that permits us to identify upcoming challenges to uplift biology and strategies and therapies for improving human health

    Orbital anastomoses of the anterior deep temporal artery

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    The anterior deep temporal artery may provide a major collateral pathway to the intracranial circulation through anastomoses with branches of the ophthalmic artery. Review of carotid angiograms in 26 patients with internal carotid artery occlusive disease revealed anterior deep temporal to ophthalmic artery anastomoses in 16 cases. This route of collateral blood flow was associated in most instances with total occlusion of the cervical portion of the internal carotid artery. Three cases demonstrating the angiographic anatomy of the anterior deep temporal artery and its potential anastomoses with branches of the ophthalmic artery are presented. L'artère temporale profonde antérieure peut être à l'origine de circulation colatérale grâce à ses anastomoses avec l'artère ophtalmique. Une telle anastomose a été constatée 16 fois sur 26 cas de thrombose de l'artère carotide interne. Über die A. temporalis anterior ist über Anastomosen zu den Ästen der A. ophthalmica ein Kollateral-Kreislauf zu den intracraniellen Gefäßabschnitten möglich. Bei 26 Patienten mit einem A. carotis interna-Verschluß zeigte sich dieser Kreislauf in 16 Fällen. Es wird über 3 Fälle ausführlich berichtet, bei denen die angiographische Anatomie der A. temporalis anterior und die möglichen Anastomosen mit Ästen der A. ophthalmica besprochen wird.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46672/1/234_2004_Article_BF00335020.pd

    MultiCellDS: a community-developed standard for curating microenvironment-dependent multicellular data

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    Exchanging and understanding scientific data and their context represents a significant barrier to advancing research, especially with respect to information siloing. Maintaining information provenance and providing data curation and quality control help overcome common concerns and barriers to the effective sharing of scientific data. To address these problems in and the unique challenges of multicellular systems, we assembled a panel composed of investigators from several disciplines to create the MultiCellular Data Standard (MultiCellDS) with a use-case driven development process. The standard includes (1) digital cell lines, which are analogous to traditional biological cell lines, to record metadata, cellular microenvironment, and cellular phenotype variables of a biological cell line, (2) digital snapshots to consistently record simulation, experimental, and clinical data for multicellular systems, and (3) collections that can logically group digital cell lines and snapshots. We have created a MultiCellular DataBase (MultiCellDB) to store digital snapshots and the 200+ digital cell lines we have generated. MultiCellDS, by having a fixed standard, enables discoverability, extensibility, maintainability, searchability, and sustainability of data, creating biological applicability and clinical utility that permits us to identify upcoming challenges to uplift biology and strategies and therapies for improving human health
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