1,721,738 research outputs found
The power of gene-based rare variant methods to detect disease-associated variation and test hypotheses about complex disease.
Get PDFGenome and exome sequencing in large cohorts enables characterization of the role of rare variation in complex diseases. Success in this endeavor, however, requires investigators to test a diverse array of genetic hypotheses which differ in the number, frequency and effect sizes of underlying causal variants. In this study, we evaluated the power of gene-based association methods to interrogate such hypotheses, and examined the implications for study design. We developed a flexible simulation approach, using 1000 Genomes data, to (a) generate sequence variation at human genes in up to 10K case-control samples, and (b) quantify the statistical power of a panel of widely used gene-based association tests under a variety of allelic architectures, locus effect sizes, and significance thresholds. For loci explaining ~1% of phenotypic variance underlying a common dichotomous trait, we find that all methods have low absolute power to achieve exome-wide significance (~5-20% power at α = 2.5 × 10(-6)) in 3K individuals; even in 10K samples, power is modest (~60%). The combined application of multiple methods increases sensitivity, but does so at the expense of a higher false positive rate. MiST, SKAT-O, and KBAC have the highest individual mean power across simulated datasets, but we observe wide architecture-dependent variability in the individual loci detected by each test, suggesting that inferences about disease architecture from analysis of sequencing studies can differ depending on which methods are used. Our results imply that tens of thousands of individuals, extensive functional annotation, or highly targeted hypothesis testing will be required to confidently detect or exclude rare variant signals at complex disease loci
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Muunnossähköauton akuston suunnittelu
Get PDFJatkuva pelko fossiilisten polttoaineiden loppumisesta ja niiden hinnan arvaamattomasta noususta lienee yksi tärkeimmistä syistä sähköautokehityksen vauhdittumiselle viime vuosina. Sähköistä liikkumista pidetään yleisesti myös ympäristöystävällisenä, koska se ei aiheuta pakokaasupäästöjä. Nykyisen sähköautokannan perusteella ei kuitenkaan voida varmasti tietää, millaisia ympäristövaikutuksia tulevaisuuden sähköautoilu aiheuttaa, koska akkujen tuotanto painottuu voimakkaasti Aasiaan.
Monet sähköautoilusta kiinnostuneet kyllästyivät jo vuosia sitten autonvalmistajien saamattomuuteen sähköauton kehityksessä, mistä syntyi harrastelijoiden muunnospajoja eri puolille maailmaa. Harrastajien on kuitenkin vaikea tehdä sähköautomuunnoksesta niin täydellistä, että se täyttäisi kaikki viranomaismääräykset niin tieliikenteen kuin sähköturvallisuudenkin osalta.
Moottori on ollut polttomoottoriautoissa yksi suurimmista kehityskohteista auton historian aikana. Sähköautoissa sen sijaan suurinta kehitystä tarvitaan akuston suhteen. Sähköakun yli 200-vuotisen historian aikana ei vielä ole saatu kehitettyä akkua, jonka energiasisältö olisi lähelläkään polttonesteiden arvoja. Nykyistä akkujen kehitystä voidaankin verrata polttomoottorin kehitykseen 1900-luvulla. Silloin autonvalmistajat kilpailivat siitä, kenellä on tehokkain tai taloudellisin moottori. Sähkömoottorin hyötysuhde on nykyään lähes poikkeuksetta yli 90 % ja sen tehotiheys on saatu polttomoottorin tehotiheyttä suuremmaksi. Toisaalta nykyisten sähköakkujen energiatiheys on vain murto-osa minkä tahansa polttonesteen arvoista.
Akkujen energiavaraston pienuutta voidaan toki korvata käyttämällä hybriditekniikkaa tai tuottamalla ajoneuvon sähköenergia polttokennoilla vedystä. Hybriditekniikka kuitenkin jättää auton riippuvaiseksi fossiilisista polttoaineista, vaikka niiden kulutus vähenee huomattavasti. Myös polttokennotekniikassa on edelleen suuria puutteita. Polttokenno toimii hyvin vain puhtaalla vedyllä, jolle ei ole kehitetty tankkausverkostoa. Jokaisen käyttäjän oma tankkauslaite taas olisi liian kallis hankinta. Monet myös pelkäävät vedyn käyttöä, koska se on huomaamaton räjähtävä kaasu. Lisäksi vedyn tuottamisen ja käyttämisen kokonaishyötysuhde on heikompi kuin sähköakkutekniikalla.Nowadays people fear the end of fossil fuel sources and greenhouse gases are being accused for warming the Earth. This might be the main reason for growing interest into electric and hybrid electric vehicles. A small group of people have been interested in full electric vehicles for years and became frustrated in that car manufactures didn’t offer electric versions of their car models. That’s why the first electric car conversions were made. It’s not easy or inexpensive to convert a car to fulfill all vehicle and electricity regulations. Luckily most of the car manufactures are starting to produce electric models in near future to respond the market’s needs. Still there are some questions that need to be answered before we can stop burning fuel in cars.
In gasoline powered cars engine has been the main component in comparison of which car is better. In electric cars that component would be the battery pack. That makes research and development of battery systems a very interesting subject. As batteries’ energy density is still just a fraction of energy density in liquid fuels, there should be lots of progress in battery systems in near future. On the other hand, electric car does not necessarily need electric batteries if the electricity could be transformed into some other form for storage. One possibility to store electric energy is to produce hydrogen with it and then use fuel cells in car to transform the hydrogen back to electricity. But hydrogen systems still have problems with efficiency and some people do not trust that an imperceptible gas would be safe to use
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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