4,003 research outputs found
The Effect of Music Tempo on Cycling Performance in Female College Students
Studies have demonstrated that fast tempo music improves performance on the treadmill, however there is a lack of research on this topic using cycle ergometers. This study was designed to determine the effects of music tempo on cycling performance. Participants (n=12) were recruited through word of mouth and completed a maximal oxygen consumption test (VO2 max) on a cycle ergometer. VO2 max results were used to determine resistance for the following trials using 65% of the power output, which was converted to kiloponds. Subjects then completed a familiarization trial that was eighteen minutes including a three-minute warm up. Subjects were told to cover as much distance as possible in the allotted time. The participants completed one trial each week for three weeks, each trial was eighteen minutes including a three-minute warm up, with either fast music (FM), slow music (SM) or no music (NM) playing. Every three minutes throughout the trials heart rate (HR), distance covered, and rate of perceived exertion (RPE) were measured. It was hypothesized that the FM would yield the best performance (the most distance covered). There was no significant difference in distance covered (p=0.431) or HR (p=0.180) at the end of the trials, however SM yielded a significantly lower RPE than FM or NM (p=0.015). The average distance covered in NM was 8.01km±1.43, SM 8.28km±1.54, FM 8.33km±1.38. The average HR in NM was 172.5bpm±19.45, SM 169.58bpm±19.08, FM 159.75bpm±21.77. The average RPE at the end of the trial in NM was 15.33±1.68, SM 14.67±1.61, FM 16±1.68. It was concluded that slow music resulted in a lower perception of effort when covering a similar distance compared to no music or fast music
A thermostable trilayer resist for niobium lift-off
We have developped a novel lift-off process for fabrication of high quality
superconducting submicron niobium structures. The process makes use of a
thermostable polymer with a high transition temperature T_{g}= 235 C and an
excellent chemical stability. The superconducting critical temperature of 100
nm wide niobium lines is above 7 K. An example of shadow evaporation of a Nb-Cu
submicron hybrid structure is given. A potential application of this process is
the fabrication of very small single electron devices using refratory metals.Comment: 6 pages, 6 eps figures, submitted to Journal of Vacuum Science and
Technology
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Calibration and evaluation of individual-based models using Approximate Bayesian Computation
AbstractThis paper investigates the feasibility of using Approximate Bayesian Computation (ABC) to calibrate and evaluate complex individual-based models (IBMs). As ABC evolves, various versions are emerging, but here we only explore the most accessible version, rejection-ABC. Rejection-ABC involves running models a large number of times, with parameters drawn randomly from their prior distributions, and then retaining the simulations closest to the observations. Although well-established in some fields, whether ABC will work with ecological IBMs is still uncertain.Rejection-ABC was applied to an existing 14-parameter earthworm energy budget IBM for which the available data consist of body mass growth and cocoon production in four experiments. ABC was able to narrow the posterior distributions of seven parameters, estimating credible intervals for each. ABC's accepted values produced slightly better fits than literature values do. The accuracy of the analysis was assessed using cross-validation and coverage, currently the best-available tests. Of the seven unnarrowed parameters, ABC revealed that three were correlated with other parameters, while the remaining four were found to be not estimable given the data available.It is often desirable to compare models to see whether all component modules are necessary. Here, we used ABC model selection to compare the full model with a simplified version which removed the earthworm's movement and much of the energy budget. We are able to show that inclusion of the energy budget is necessary for a good fit to the data. We show how our methodology can inform future modelling cycles, and briefly discuss how more advanced versions of ABC may be applicable to IBMs. We conclude that ABC has the potential to represent uncertainty in model structure, parameters and predictions, and to embed the often complex process of optimising an IBM's structure and parameters within an established statistical framework, thereby making the process more transparent and objective
Excavations in the Acheulean Levels at the Earlier Stone Age site of Canteen Koppie, Northern Province, South Africa
The fluvial gravels of the river Vaal in South Africa have long been known as a source for Earlier Stone Age (ESA) artefacts. Most were discovered through the open cast mining for diamonds that has left very little in situ fluvial sediment remaining today. The site of Canteen Koppie is an internationally famous location with a reputation for prolific Acheulean artefacts, especially handaxes and the enigmatic prepared core and Levallois-like technology known as Victoria West. Our understanding of this site, and most other Vaal locations, is almost solely based on highly selected artefact collections. Here, we report on the first controlled excavations ever to be conducted at Canteen Koppie. The deposits are likely to date to the Early and Middle Pleistocene, and our excavations sample the full depth of the stratigraphic sequence. The lower units, first identified in these excavations, add a considerable time depth to the Acheulean occupation of the site, making this the longest chrono-stratigraphic sequence in South Africa to our knowledge. Given the current international interest in the origins of Levallois/prepared core technology (PCT), its occurrence in Unit 2b Upper, and its presence alongside Victoria West technology in Unit 2a has significant implications for debates on the role of Victoria West in the origins of PCT. From the Canteen Koppie evidence, Levallois and Victoria West are clearly rooted in the Acheulean.RésuméOn sait depuis longtemps que les graviers fluviaux de la rivière Vaal en Afrique du Sud sont une source d'artefacts de l'âge de pierre ancien (ESA). Ils ont été découverts pour la plupart au cours de l'extraction de diamants dans des mines à ciel ouvert, ce qui fait qu'il ne reste que très peu de sédiments fluviaux in situ aujourd'hui. Le site de Canteen Koppie est un lieu célèbre dans le monde entier, réputé pour l'abondance de ses artefacts acheuléens, en particulier les bifaces et la technologie enigmatique des nucléus préparés semblable au Levallois connue sous le nom de Victoria West. Notre compréhension de ce site, et de la plupart des autres lieux du Vaal, repose presque uniquement sur des collections d'artefacts extrèmement sélectionnés. Ici, nous faisons le compte rendu des premières fouilles contrôlées jamais menées à Canteen Koppie. Les dépôts datent probablement du début et du milieu du pléistocène et nos excavations prennent des échantillons de l'ensemble de la profondeur de la séquence stratigraphique. Les unités les plus basses, identifiées pour la première fois au cours de ces fouilles, ajoutent une profondeur temporelle considérable à l'occupation acheuléenne du site, elles en font la plus longue séquence chronostratigraphique d'Afrique du Sud à notre connaissance. Etant donné l'actuel intérêt international pour les origines de la technologie Levallois/nucléus préparé (PCT), sa rencontre dans l'Unité 2b Supérieure, et sa présence à côté de la technologie Victoria West dans l'Unité 2a ont d'importantes implications pour les débats sur le rôle de Victoria West dans les origines de PCT. D'après les témoignages de Canteen Koppie,il est clair que Levallois et Victoria West ont leurs racines dans l'acheuléen.ZusammenfassungDie Schwemmkiese des Flusses Vaal in Südafrika sind seit langem als Fundort altsteinzeitlicher Artefakte bekannt. Meist wurden sie während des Diamanttagebaus gefunden, durch den heute sehr wenige Sedimente noch in situ erhalten sind. Der Fundplatz Canteen Koppie ist ein international weithin bekannter Ort, der berühmt ist für reiche Artefakte des Acheuléen, insbesondere Faustkeile und die rätselhafte, an Levallois erinnernde Kerntechnologie, die als Victoria West bekannt ist. Unser Verständnis dieses Fundplatzes, wie auch der meisten anderen Orte entlang des Vaal, basiert fast ausschließlich auf einer eng begrenzten Auswahl von Artefaktensembles. Hier berichten wir über die erste systematische Ausgrabung, die je in Canteen Koppie durchgeführt wurde. Die Schichten datieren wahrscheinlich ins Früh- und Mittelpleistozän; unsere Grabungen erfassten die gesamte Ausdehnung der stratigraphischen Abfolge. Die unteren Einheiten, die zuerst in den Grabungen identifiziert werden konnten, vergrößern die zeitliche Tiefe der Acheuléen-zeitlichen Nutzung des Ortes erheblich, wodurch dies nach unserem Wissen die längste chrono-stratigraphische Sequenz in Südafrika ist. Aufgrund des gegenwärtigen Interesses an den Ursprüngen der Levallois-Technik bzw. Technik der vorbereiteten Kerne (prepared core technology, PCT) ist ihr Auftreten in Unit 2b Upper und das Vorhandensein in Unit 2a, gemeinsam mit Victoria West-Technologie, von besonderer Bedeutung für die Diskussionen über die Rolle, die Victoria West bei der Entstehung von PCT spielt. Anhand der Beobachtungen in Canteen Koppie können wir festhalten, dass Levallois und Victoria West sicher im Acheuléen wurzeln.RésuménLas gravas fluviales del Rio Vaal en Sudáfrica han sido conocidas desde antiguo como una fuente de artefactos de la Primera Edad de Piedra (ESA en su acrónimo inglés). La mayorÃa han sido descubiertos al buscar diamantes al aire libre que ha dejado muy pocos sedientos fluviales in situ hoy en dÃa. El yacimiento de Canteen Koppie es un emplazamiento internacionalmente famoso con una reputación de ser especialmente prolijo en artefactos del Achelense, especialmente hachas de mano y los enigmáticos núcleos preparados y la tecnologÃa de estilo Levallois conocida como ‘Victoria West’. Nuestra comprensión de este yacimiento, y de la mayorÃa de los otros yacimientos en el Vaal, se basa casi exclusivamente en una serie de colecciones de artefactos altamente seleccionados. Este trabajo informa sobre las primeras excavaciones controladas jamás realizadas en Canteen Koppie. Los depósitos datan más probablemente al Pleistoceno Alto y Medio, y nuestra excavación cató toda la profundidad de la secuencia estratigráfica. Las capas más bajas, identificadas por primera vez en esta excavación, añaden una considerable profundidad temporal a la ocupación Achelense del yacimiento, y lo convierten, que sepamos, en la secuencia crono-estratigráfica más larga de Sudáfrica. Dado el interés internacional actual en los orÃgenes de la tecnologÃa Levallois/núcleos preparados (PCT en su acrónimo inglés), su aparición en el Nivel 2b Superior, y su presencia junto con la tecnologÃa Victoria West en el Nivel 2a tiene significativas consecuencias para los debates sobre el papel de Victoria West en los orÃgenes del PCT. Por lo que indica la evidencia de Canteen Koppie, las tecnologÃas Levallois y Victoria West están ambas claramente enraizadas en el Achelense
Rapid evolution of novel biotic interactions in the UK Brown Argus butterfly uses genomic variation from across its geographical range
Understanding the rate and extent to which populations can adapt to novel environments at their ecological margins is fundamental to predicting the persistence of biological communities during ongoing and rapid global change. Recent range expansion in response to climate change in the UK butterfly Aricia agestis is associated with the evolution of novel interactions with a larval food plant, and the loss of its ability to use an ancestral host species. Using ddRAD analysis of 61,210 variable SNPs from 261 females from throughout the UK range of this species, we identify genomic regions at multiple chromosomes that are associated with evolutionary responses, and their association with demographic history and ecological variation. Gene flow appears widespread throughout the range, despite the apparently fragmented nature of the habitats used by this species. Patterns of haplotype variation between selected and neutral genomic regions suggest that evolution associated with climate adaptation is polygenic, resulting from the independent spread of alleles throughout the established range of this species, rather than the colonization of pre-adapted genotypes from coastal populations. These data suggest that rapid responses to climate change do not depend on the availability of pre-adapted genotypes. Instead, the evolution of novel forms of biotic interaction in A. agestis has occurred during range expansion, through the assembly of novel genotypes from alleles from multiple localities
SoLid : Search for Oscillations with Lithium-6 Detector at the SCK-CEN BR2 reactor
Sterile neutrinos have been considered as a possible explanation for the recent reactor and Gallium anomalies arising from reanalysis of reactor flux and calibration data of previous neutrino experiments. A way to test this hypothesis is to look for distortions of the anti-neutrino energy caused by oscillation from active to sterile neutrino at close stand-off (similar to 6-8m) of a compact reactor core. Due to the low rate of anti-neutrino interactions the main challenge in such measurement is to control the high level of gamma rays and neutron background.
The SoLid experiment is a proposal to search for active-to-sterile anti-neutrino oscillation at very short baseline of the SCK center dot CEN BR2 research reactor.
This experiment uses a novel approach to detect anti-neutrino with a highly segmented detector based on Lithium-6. With the combination of high granularity, high neutron-gamma discrimination using 6LiF:ZnS(Ag) and precise localization of the Inverse Beta Decay products, a better experimental sensitivity can be achieved compared to other state-of-the-art technology. This compact system requires minimum passive shielding allowing for very close stand off to the reactor. The experimental set up of the SoLid experiment and the BR2 reactor will be presented. The new principle of neutrino detection and the detector design with expected performance will be described. The expected sensitivity to new oscillations of the SoLid detector as well as the first measurements made with the 8 kg prototype detector deployed at the BR2 reactor in 2013-2014 will be reported
The value of carbon sequestration and storage in coastal habitats
Coastal margin habitats are globally significant in terms of their capacity to sequester and store carbon, but their continuing decline, due to environmental change and human land use decisions, is reducing their capacity to provide this ecosystem service. In this paper the UK is used as a case study area to develop methodologies to quantify and value the ecosystem service of blue carbon sequestration and storage in coastal margin habitats. Changes in UK coastal habitat area between 1900 and 2060 are documented, the long term stocks of carbon stored by these habitats are calculated, and the capacity of these habitats to sequester CO2 is detailed. Changes in value of the carbon sequestration service of coastal habitats are then projected for 2000–2060 under two scenarios, the maintenance of the current state of the habitat and the continuation of current trends of habitat loss. If coastal habitats are maintained at their current extent, their sequestration capacity over the period 2000–2060 is valued to be in the region of £1 billion UK sterling (3.5% discount rate). However, if current trends of habitat loss continue, the capacity of the coastal habitats both to sequester and store CO2 will be significantly reduced, with a reduction in value of around £0.25 billion UK sterling (2000–2060; 3.5% discount rate). If loss-trends due to sea level rise or land reclamation worsen, this loss in value will be greater. This case study provides valuable site specific information, but also highlights global issues regarding the quantification and valuation of carbon sequestration and storage. Whilst our ability to value ecosystem services is improving, considerable uncertainty remains. If such ecosystem valuations are to be incorporated with confidence into national and global policy and legislative frameworks, it is necessary to address this uncertainty. Recommendations to achieve this are outlined
Pro-Apoptotic Apoptosis Protease–Activating Factor 1 (Apaf-1) Has a Cytoplasmic Localization Distinct from Bcl-2 or Bcl-XL
How Bcl-2 and its pro-survival relatives prevent activation of the caspases that mediate apoptosis is unknown, but they appear to act through the caspase activator apoptosis protease–activating factor 1 (Apaf-1). According to the apoptosome model, the Bcl-2–like proteins preclude Apaf-1 activity by sequestering the protein. To explore Apaf-1 function and to test this model, we generated monoclonal antibodies to Apaf-1 and used them to determine its localization within diverse cells by subcellular fractionation and confocal laser scanning microscopy. Whereas Bcl-2 and Bcl-xL were prominent on organelle membranes, endogenous Apaf-1 was cytosolic and did not colocalize with them, even when these pro-survival proteins were overexpressed or after apoptosis was induced. Immunogold electron microscopy confirmed that Apaf-1 was dispersed in the cytoplasm and not on mitochondria or other organelles. After the death stimuli, Bcl-2 and Bcl-xL precluded the release of the Apaf-1 cofactor cytochrome c from mitochondria and the formation of larger Apaf-1 complexes, which are steps that presage apoptosis. However, neither Bcl-2 nor Bcl-xL could prevent the in vitro activation of Apaf-1 induced by the addition of exogenous cytochrome c. Hence, rather than sequestering Apaf-1 as proposed by the apoptosome model, Bcl-2–like proteins probably regulate Apaf-1 indirectly by controlling upstream events critical for its activation
Modeling postbreakup landscape development and denudational history across the southeast African (Drakensberg Escarpment) margin
The Small and the Dead: A Review of Ancient DNA Studies Analysing Micromammal Species
The file attached is the Published/publisher’s pdf version of the article
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