CiteULike: OriginalLurch's library [273 articles]

Inaugural Article: The direction of gut looping is established by changes in the extracellular matrix and in cell:cell adhesion

Natasza Kurpios — 2008-06-25T09:21:50-00:00

Proceedings of the National Academy of Sciences, Vol. 105, No. 25. (24 June 2008), pp. 8499-8506.

The counterclockwise coiling of the intestines is initiated by a leftward tilt of the primitive gut tube, imparted by left-right asymmetries in the architecture of the dorsal mesentery. In silico analysis suggests that this is achieved by synergistic changes in its epithelium and mesenchyme. Within the mesenchymal compartment, cells are more densely packed on the left than on the right. In silico results indicate that this property can result from asymmetries in both extracellular matrix (ECM) and cell:cell adhesion. We find that the dorsal mesentery ECM is indeed left-right asymmetric and moreover that the adhesion molecule N-cadherin is expressed exclusively on the left side. These asymmetries are regulated by the asymmetrically expressed transcription factors Pitx2 and Isl1. Functional studies demonstrate that N-cadherin acts upstream of the changes in the ECM and is both necessary and sufficient to explain the asymmetric packing of the mesenchymal cells. 10.1073/pnas.0803578105

Inaugural Article: Historical contingency and the evolution of a key innovation in an experimental population of Escherichia coli

Zachary Blount — 2008-06-05T14:39:36-00:00

Proceedings of the National Academy of Sciences (4 June 2008), 0803151105.

The role of historical contingency in evolution has been much debated, but rarely tested. Twelve initially identical populations of Escherichia coli were founded in 1988 to investigate this issue. They have since evolved in a glucose-limited medium that also contains citrate, which E. coli cannot use as a carbon source under oxic conditions. No population evolved the capacity to exploit citrate for >30,000 generations, although each population tested billions of mutations. A citrate-using (Cit+) variant finally evolved in one population by 31,500 generations, causing an increase in population size and diversity. The long-delayed and unique evolution of this function might indicate the involvement of some extremely rare mutation. Alternately, it may involve an ordinary mutation, but one whose physical occurrence or phenotypic expression is contingent on prior mutations in that population. We tested these hypotheses in experiments that "replayed" evolution from different points in that population's history. We observed no Cit+ mutants among 8.4 x 1012 ancestral cells, nor among 9 x 1012 cells from 60 clones sampled in the first 15,000 generations. However, we observed a significantly greater tendency for later clones to evolve Cit+, indicating that some potentiating mutation arose by 20,000 generations. This potentiating change increased the mutation rate to Cit+ but did not cause generalized hypermutability. Thus, the evolution of this phenotype was contingent on the particular history of that population. More generally, we suggest that historical contingency is especially important when it facilitates the evolution of key innovations that are not easily evolved by gradual, cumulative selection. 10.1073/pnas.0803151105

The Role of Rivalry: Public Goods Versus Common-Pool Resources

Jose Apesteguia — 2006-09-07T10:59:09-00:00

Journal of Conflict Resolution, Vol. 50, No. 5. (1 October 2006), pp. 646-663.

Despite a large theoretical and empirical literature on public goods and common-pool resources, a systematic comparison of these two types of social dilemmas is lacking. In fact, there is some confusion about these two types of dilemma situations. As a result, they are often treated alike. In line with the theoretical literature, the authors argue that the degree of rivalry is the fundamental difference between the two games. Furthermore, they experimentally study behavior in a quadratic public good and a quadratic common-pool resource game with identical Pareto-optimum but divergent interior Nash equilibria. The results show that participants clearly perceive the differences in rivalry. Aggregate behavior in both games starts relatively close to Pareto efficiency and converges quickly to the respective Nash equilibrium. 10.1177/0022002706290433

Global and Local Architecture of the Mammalian microRNA-Transcription Factor Regulatory Network.

Reut Shalgi — 2007-07-17T17:37:08-00:00

PLoS Comput Biol, Vol. 3, No. 7. (13 July 2007)

microRNAs (miRs) are small RNAs that regulate gene expression at the posttranscriptional level. It is anticipated that, in combination with transcription factors (TFs), they span a regulatory network that controls thousands of mammalian genes. Here we set out to uncover local and global architectural features of the mammalian miR regulatory network. Using evolutionarily conserved potential binding sites of miRs in human targets, and conserved binding sites of TFs in promoters, we uncovered two regulation networks. The first depicts combinatorial interactions between pairs of miRs with many shared targets. The network reveals several levels of hierarchy, whereby a few miRs interact with many other lowly connected miR partners. We revealed hundreds of "target hubs" genes, each potentially subject to massive regulation by dozens of miRs. Interestingly, many of these target hub genes are transcription regulators and they are often related to various developmental processes. The second network consists of miR-TF pairs that coregulate large sets of common targets. We discovered that the network consists of several recurring motifs. Most notably, in a significant fraction of the miR-TF coregulators the TF appears to regulate the miR, or to be regulated by the miR, forming a diversity of feed-forward loops. Together these findings provide new insights on the architecture of the combined transcriptional-post transcriptional regulatory network.

City Indicators: Now to Nanjing

Daniel Hoornweg — 2008-06-03T15:08:41-00:00

Social Science Research Network Working Paper Series (1 January 2007)

This paper provides the key elements to develop an integrated approach for measuring and monitoring city performance globally. The paper reviews the role of cities and why indicators are important. Then it discusses past approaches to city indicators and the systems developed to date, including the World Bank's initiatives. After identifying the strengths and weaknesses of past experiences, it discusses the characteristics of optimal indicators. The paper concludes with a proposed plan to develop standardized indicators that emphasize the importance of indicators that are measurable, replicable, potentially predictive, and most important, consistent and comparable over time and across cities. As an innovative characteristic, the paper includes subjective measures in city indicators, such as well-being, happy citizens, and trust.

Shirky: A Group Is Its Own Worst Enemy

2007-12-01T00:08:49-00:00

Here Comes Everybody: The Power of Organizing Without Organizations

Clay Shirky — 2008-05-30T09:07:01-00:00

(28 February 2008)

/Message: Fred Wilson on Leaving The Instigator Out: Small Worlds v Big World

2008-05-29T21:26:27-00:00

Identification and characterization of a tri-partite hydrophobin from Claviceps fusiformis . A novel type of class II hydrophobin

Onno de Vries — 2008-04-22T03:29:30-00:00

European Journal of Biochemistry, Vol. 262, No. 2. (1999), pp. 377-385.

A new type of hydrophobin is encoded by an abundant mRNA of Claviceps fusiformis. The predicted amino-acid sequence of the protein, dubbed CFTH1, shows a putative signal sequence for secretion, followed by three class II hydrophobin domains each preceded by glycine/asparagine rich regions. SDS/PAGE analysis of 60% ethanol extractions of C. fusiformis mycelia from shaken cultures showed CFTH1 at the 50-55-kDa position. N-terminal sequencing of both untreated mature CFTH1 and of a fragment obtained by trypsin digestion revealed that CFTH1 is not processed between the hydrophobin domains. Mass spectroscopy showed a mass of about 36 500 Da, which is about 1500 Da higher than the mass predicted from the constituent amino acids, indicating post-translational modification but not glycosylation. Purified CFTH1 self-assembled at hydrophilic/hydrophobic interfaces and, after assembly at a water/air interface, it was found to be highly surface active. Antibodies raised against CFTH1 localized the protein in a mucilageous coat surrounding submerged vegetative hyphae in liquid shaken culture and, as a discrete layer of about 10 nm thickness at the surface of aerial hyphae of standing cultures, suggesting a role in the formation of aerial hyphae.

Initial sequencing and comparative analysis of the mouse genome.

RH Waterston — 2004-11-22T00:17:30-00:00

Nature, Vol. 420, No. 6915. (5 December 2002), pp. 520-562.

The sequence of the mouse genome is a key informational tool for understanding the contents of the human genome and a key experimental tool for biomedical research. Here, we report the results of an international collaboration to produce a high-quality draft sequence of the mouse genome. We also present an initial comparative analysis of the mouse and human genomes, describing some of the insights that can be gleaned from the two sequences. We discuss topics including the analysis of the evolutionary forces shaping the size, structure and sequence of the genomes; the conservation of large-scale synteny across most of the genomes; the much lower extent of sequence orthology covering less than half of the genomes; the proportions of the genomes under selection; the number of protein-coding genes; the expansion of gene families related to reproduction and immunity; the evolution of proteins; and the identification of intraspecies polymorphism.

robert zubek / blog :: Viral Coefficient Calculation

2008-05-05T07:14:44-00:00

Improved prediction of protein-protein binding sites using a support vector machines approach

James Bradford — 2005-04-15T16:19:08-00:00

Bioinformatics, Vol. 21, No. 8. (15 April 2005), pp. 1487-1494.

Enumerating Contingency Tables via Random Permanents

Alexander Barvinok — 2008-04-16T14:46:50-00:00

Combinatorics, Probability and Computing, Vol. 17, No. 01. (2007), pp. 1-19.

Given m positive integers R = (ri), n positive integers C = (cj) such that Σri = Σcj = N, and mn non-negative weights W=(wij), we consider the total weight T=T(R, C; W) of non-negative integer matrices D=(dij) with the row sums ri, column sums cj, and the weight of D equal to <img src="/fulltext_content/CPC/CPC17_01/S0963548307008668_inline1.gif" alt="$∏ w_ij^d_ij$"></img>. For different choices of R, C, and W, the quantity T(R,C; W) specializes to the permanent of a matrix, the number of contingency tables with prescribed margins, and the number of integer feasible flows in a network. We present a randomized algorithm whose complexity is polynomial in N and which computes a number T′=T′(R,C;W) such that T′ ≤ T ≤ α(R,C)T′ where <img src="/fulltext_content/CPC/CPC17_01/S0963548307008668_inline2.gif" alt="$α(R,C) = \min \bigl{∏ r_i! r_i^-r_i, \ ∏ c_j! c_j^-c_j \bigr} N^N/N!$"></img>. In many cases, ln T′ provides an asymptotically accurate estimate of ln T. The idea of the algorithm is to express T as the expectation of the permanent of an N × N random matrix with exponentially distributed entries and approximate the expectation by the integral T′ of an efficiently computable log-concave function on <img src="/fulltext_content/CPC/CPC17_01/xs211D.gif" alt="xs211D"></img>mn.

Logic in Computer Science: Modelling and Reasoning About Systems by Michael Huth and Mark Ryan, second edition. ISBN 0 521 54310 X.

Gergely Buday — 2008-04-16T14:23:57-00:00

Journal of Functional Programming, Vol. 18, No. 03. (2008), pp. 421-422.

Semmelweis and the aetiology of puerperal sepsis 160 years on: an historical review

Noakes — 2008-04-16T14:20:49-00:00

Epidemiology and Infection, Vol. 136, No. 01. (2007), pp. 1-9.

It is generally accepted that Professor Ignaz Semmelweis was the first to identify the mode of transmission of puerperal sepsis. However no appropriate statistical analysis of Semmelweis's data supporting his theory has been reported. Mean annual percent maternal mortality rates for the Allgemeines Krankenhaus and Dublin Maternity Hospitals (1784–1858) were analysed. The introduction of pathological anatomy at the Allgemeines Krankenhaus in 1823 was associated with increased mortality. After 1840 maternal mortality was higher in Clinic 1 which was staffed by male obstetricians and medical students who, unlike the midwives in Clinic 2, attended autopsies. The introduction of chlorine washing of the male clinicians’ hands in Clinic 1 by Semmelweis in 1847 reduced mortality, whereas the cessation of handwashing after Semmelweis left Vienna in 1850 was associated with increased mortality. This statistical analysis supports Semmelweis's hypothesis that ‘the cadaveric particles adhering to the hand had … caused the preponderant mortality in the first Clinic’.

Trend Detection in Folksonomies

Andreas Hotho — 2008-02-21T11:23:27-00:00

Semantic Multimedia (2006), pp. 56-70.

As the number of resources on the web exceeds by far the number of documents one can track, it becomes increasingly difficult to remain up to date on ones own areas of interest. The problem becomes more severe with the increasing fraction of multimedia data, from which it is difficult to extract some conceptual description of their contents. One way to overcome this problem are social bookmark tools, which are rapidly emerging on the web. In such systems, users are setting up lightweight conceptual structures called folksonomies, and overcome thus the knowledge acquisition bottleneck. As more and more people participate in the effort, the use of a common vocabulary becomes more and more stable. We present an approach for discovering topic-specific trends within folksonomies. It is based on a differential adaptation of the PageRank algorithm to the triadic hypergraph structure of a folksonomy. The approach allows for any kind of data, as it does not rely on the internal structure of the documents. In particular, this allows to consider different data types in the same analysis step. We run experiments on a large-scale real-world snapshot of a social bookmarking system.

shimenawa - Category: Publishing

2008-04-04T10:27:43-00:00

Derek's Virtual Slide Rule Gallery

2008-04-02T19:00:37-00:00

Datawocky: More data usually beats better algorithms

2008-03-31T07:39:22-00:00

Actor-network theory and anthropology after science, technology, and society

Robert Oppenheim — 2007-11-08T15:27:35-00:00

Anthropological Theory, Vol. 7, No. 4. (1 December 2007), pp. 471-493.

This essay makes a case for the value of actor-network theory (ANT) to anthropology beyond its most usual deployment in studies of science, technology, and society (STS). Through a review of two recent ANT works against both the longer-term development of the approach and common patterns of anthropological appropriation and critique over the past several years, it argues that `about-ANT' and `across-ANT' understandings that emphasize an applicability to technoscience or situations of hybridity should give way to `among-ANT' readings that highlight its quality as a domain-independent ontology of association. Most centrally, it offers a reading of the constitutive spatialities of ANT itself and of spatiality as an important ANT concern, with the suggestion that a greater appreciation for this dimension of the literature might form the basis of broader and more varied anthropological engagements. 10.1177/1463499607083430

Race, Judicial Discretion, and the Death Penalty

Marvin Wolfgang — 2007-11-25T17:29:07-00:00

The ANNALS of the American Academy of Political and Social Science, Vol. 407, No. 1. (1 May 1973), pp. 119-133.

The record of executions in the United States has long shown that black defendants are disproportionately subjected to this sanction. But racial differentials in the use of the death penalty may not alone reveal the existence of racial discrimination. The Supreme Court in the Furman decision ruled that the death penalty is unconstitutional because it is a "cruel and unusual" punishment. Some allusions to racial discrimination appeared in the opinions, but more evidence seems called for. Some earlier studies of racial differentials in sentencing are reviewed, followed by a summary of the research procedure and conclusions from an elaborate study of sentencing for rape in states where that offense has been a capital crime. Strong statistically significant differences in the proportions of blacks sentenced to death, compared to whites, when a variety of nonracial aggravating circumstances are considered, permit the conclusion that the sentencing differentials are the product of racial discrimination. 10.1177/000271627340700110

Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond

Maciej Lewenstein — 2007-11-25T02:19:31-00:00

Advances in Physics, Vol. 56, No. 2. (2007), pp. 243-379.

We review recent developments in the physics of ultracold atomic and molecular gases in optical lattices. Such systems are nearly perfect realisations of various kinds of Hubbard models, and as such may very well serve to mimic condensed matter phenomena. We show how these systems may be employed as quantum simulators to answer some challenging open questions of condensed matter, and even high energy physics. After a short presentation of the models and the methods of treatment of such systems, we discuss in detail, which challenges of condensed matter physics can be addressed with (i) disordered ultracold lattice gases, (ii) frustrated ultracold gases, (iii) spinor lattice gases, (iv) lattice gases in “artificial” magnetic fields, and, last but not least, (v) quantum information processing in lattice gases. For completeness, also some recent progress related to the above topics with trapped cold gases will be discussed. <blockquote>Motto: </blockquote> <blockquote>There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy 1 </blockquote>

Electronic structure calculations using dynamical mean field theory

K Held — 2008-03-15T11:46:42-00:00

Advances in Physics, Vol. 56, No. 6. (2007), pp. 829-926.

The calculation of the electronic properties of materials is an important task of solid-state theory, albeit particularly difficult if electronic correlations are strong, e.g., in transition metals, their oxides and in f-electron systems. The standard approach to material calculations, the density functional theory in its local density approximation (LDA), incorporates electronic correlations only very rudimentarily and fails if the correlations are strong. Encouraged by the success of dynamical mean field theory (DMFT) in dealing with strongly correlated model Hamiltonians, physicists from the bandstructure and the many-body communities have joined forces and developed a combined LDA + DMFT method recently. Depending on the strength of electronic correlations, this new approach yields a weakly correlated metal as in the LDA, a strongly correlated metal or a Mott insulator. This approach is widely regarded as a breakthrough for electronic structure calculations of strongly correlated materials. We review this LDA + DMFT method and also discuss alternative approaches to employ DMFT in electronic structure calculations, e.g., by replacing the LDA part with the so-called GW approximation. Different methods to solve the DMFT equations are introduced with a focus on those that are suitable for realistic calculations with many orbitals. An overview of the successful application of LDA + DMFT to a wide variety of materials, ranging from Pu and Ce, to Fe and Ni, to numerous transition metal oxides, is given.

Look before you leak | InfoWorld | Weblog | February 20, 2008 | By Robert X. Cringely

2008-02-21T09:44:36-00:00

HT06, tagging paper, taxonomy, Flickr, academic article, to read

Cameron Marlow — 2006-08-24T20:16:54-00:00

(2006), pp. 31-40.

In recent years, tagging systems have become increasingly popular. These systems enable users to add keywords (i.e., "tags") to Internet resources (e.g., web pages, images, videos) without relying on a controlled vocabulary. Tagging systems have the potential to improve search, spam detection, reputation systems, and personal organization while introducing new modalities of social communication and opportunities for data mining. This potential is largely due to the social structure that underlies many of the current systems.Despite the rapid expansion of applications that support tagging of resources, tagging systems are still not well studied or understood. In this paper, we provide a short description of the academic related work to date. We offer a model of tagging systems, specifically in the context of web-based systems, to help us illustrate the possible benefits of these tools. Since many such systems already exist, we provide a taxonomy of tagging systems to help inform their analysis and design, and thus enable researchers to frame and compare evidence for the sustainability of such systems. We also provide a simple taxonomy of incentives and contribution models to inform potential evaluative frameworks. While this work does not present comprehensive empirical results, we present a preliminary study of the photo-sharing and tagging system Flickr to demonstrate our model and explore some of the issues in one sample system. This analysis helps us outline and motivate possible future directions of research in tagging systems.

Top-10 Application-Design Mistakes (Jakob Nielsen's Alertbox)

2008-02-19T15:47:44-00:00

As We May Think

2005-12-27T10:57:26-00:00

RealThai

2008-02-17T12:18:16-00:00

Federal Lab Says It Can Harvest Fuel From Air (With a Catch) - Dot Earth - Climate Change and Sustainability - New York Times Blog

2008-02-16T12:33:04-00:00

Comparing Six Ways to Identify Top Blogs in Any Niche - ReadWriteWeb

2008-02-16T11:37:05-00:00

Michael Nielsen » Intellectual property, automated contracts, and the free flow of information

2008-02-14T13:41:34-00:00

Influence: Science and Practice (4th Edition)

Robert Cialdini — 2006-06-26T04:56:24-00:00

(29 June 2000)

The initial version of Influence was designed for the popular reader, and as such, an attempt was made to write it in an engaging style. In the subsequent versions, that style is retained, but in addition, I present the research evidence for my statements, recommendations, and conclusions. Although they are dramatized and corroborated through such devices as interviews, quotes, and systematic personal observations, the conclusions of Influence are based on controlled, psychological research. This fact allows the instructor, the student, and the popular reader to feel confident that the book is not "pop" psychology but represents work that is scientifically grounded. The subsequent versions also provide new and updated material, chapter summaries, and study questions to enhance its classroom utility. A potentially attractive feature of the present version of Influence lies in its ability to serve as an enjoyable, practical, yet scientifically documented text for both students and the general reader. For students, one way to view the book, then, is to see it as a refreshing change of pace (from standard text material) that does not retreat from scientific respectability. In a related vein, for both students and the general reader, the book might be seen as a way to demonstrate that, properly presented, what often seems like dry science can actually prove to be lively, useful, and relevant to all readers' personal lives. COMMENT ON THE FOURTH EDITION OF INFLUENCE: SCIENCE AND PRACTICE It has been some time since Influence was last published. In the interim, some things have happened that deserve a place in this new edition. First, we now know more about the influence process than before. The study of persuasion, compliance, and change has advanced, and the pages that follow have been adapted to reflect that progress. In addition to an overall update of the material, I have expanded a feature that was stimulated by the responses of prior readers. This feature highlights the experiences of individuals who have read Influence, recognized how one of the principles worked on (or for) them in a particular instance, and wrote to me describing the event. Their descriptions, which appear in the "Reader's Reports" in each chapter, illustrate how easily and frequently we can fall victim to the influence process in our everyday lives. An array of people deserve and have my appreciation for their aid in making Influence possible. Several of my academic colleagues read and provided perceptive comments on the entire manuscript in its initial draft form, greatly strengthening the subsequent version. They are Gus Levine, Doug Kenrick, Art Beaman, and Mark Zanna. In addition, the first draft was read by a few family members and friends Richard and Gloria Cialdini, Bobette Gorden, and Ted Hall-who offered not only much-needed emotional support but insightful substantive commentary as well. A second, larger group provided helpful suggestions for selected chapters or groups of chapters: Todd Anderson, Sandy Braver, Catherine Chambers, Judi Cialdini, Nancy Eisenberg, Larry Ettkin, Joanne Gersten, Jeff Goldstein, Betsy Hans, Valerie Hans, Joe Hepworth, Holly Hunt, Ann Inskeep, Barry Leshowitz, Darwyn Linder, Debbie Littler, John Mowen, Igor Pavlov, Janis Posner, Trish Puryear, Marilyn Rall, John Reich, Peter Reingen, Diane Ruble, Phyllis Sensenig, Roman Sherman, and Henry Wellman. Certain people were instrumental at the beginning stages. John Staley was the first publishing professional to recognize the project's potential. Jim Sherman, Al Goethals, John Keating, Dan Wagner, Dalmas Taylor, Wendy Wood, and David Watson provided early, positive reviews that encouraged author and editors alike. My editors at Allyn and Bacon, Carolyn Merrill and Jodi Devine, were consistently congenial, helpful, and insightful. I would like to thank the following users of the third edition for their feedback during a telephone survey: Emory Griffin, Wheaton College; Robert Levine, California State, Fresno; Jeffrey Lewin, Georgia State University; David Miller, Daytona Beach Community College; Lois Mohr, Georgia State University; and Richard Rogers, Daytona Beach Community College. The third edition benefited substantially from the reviews of Assaad Azzi, Yale University; Robert M. Brady, University of Arkansas; Brian M. Cohen, University of Texas at San Antonio; Christian B. Crandall, University of Florida; Catherine Goodwin, University of Alaska; Robert G. Lowder, Bradley University; James W. Michael, Jr., Virginia Polytechnic Institute and State University; Eugene P. Sheehan, University of Northern Colorado; Jefferson A. Singer, Connecticut College; and Sandi W. Smith, Michigan State University. Finally, throughout the project, no one was more on my side than Bobette Gorden, who lived every word with me. I wish to thank the following individuals who-either directly or through their course instructors-contributed the "Reader's Reports" used in this edition: Pat Bobbs, Annie Carto, William Cooper, Alicia Friedman, William Graziano, Mark Hastings, Endayehu Kendie, Danuta Lubnicka, James Michaels, Steven Moysey, Paul Nail, Alan J. Resnik, Daryl Retzlaff, Geofrey Rosenberger, Dan Swift, and Karla Vasks. I would also like to invite new readers to contribute similar "Reports" for possible publication in a future edition. They can be sent to me at the Department of Psychology, Arizona State University, Tempe, AZ 85287-1104 or Robert.Cialdini@ ASU.EDU. Finally, more influence-relevant information can be obtained at Influenceatwork.com. ALIGN="right">R.B.C.

Untitled

2008-02-13T15:27:09-00:00

Quantum Theory of Attosecond XUV Pulse Measurement by Laser Dressed Photoionization

Markus Kitzler — 2008-02-13T15:14:39-00:00

Physical Review Letters, Vol. 88, No. 17. (16 April 2002), 173904.

The first reported measurements of single attosecond pulses use laser dressed single-photon extreme ultraviolet (XUV) ionization of gas atoms. The determination of XUV pulse duration from the electron spectrum is based on a classical theory. Although classical models are known to give a qualitatively correct description of strong laser atom interaction; the validity must be scrutinized by a quantum-mechanical analysis. We establish a theoretical framework for the accurate temporal characterization of attosecond XUV pulses. Our analysis reveals an improved scheme that allows for direct experimental discrimination between single and multiple attosecond pulses.

Illegal downloaders could face UK internet ban - tech - 12 February 2008 - New Scientist Tech

2008-02-13T11:12:23-00:00

Evidence for a strong genetic influence on childhood adiposity despite the force of the obesogenic environment

Jane Wardle — 2008-02-07T14:00:03-00:00

Am J Clin Nutr, Vol. 87, No. 2. (1 February 2008), pp. 398-404.

Background: Body mass index (BMI) has been shown to be highly heritable, but most studies were carried out in cohorts born before the onset of the "obesity epidemic." Objective: We aimed to quantify genetic and environmental influences on BMI and central adiposity in children growing up during a time of dramatic rises in pediatric obesity. Design: We carried out twin analyses of BMI and waist circumference (WC) in a UK sample of 5092 twin pairs aged 811 y. Quantitative genetic model-fitting was used for the univariate analyses, and bivariate quantitative genetic model-fitting was used for the analysis of covariance between BMI and WC. Results: Quantitative genetic model-fitting confirmed substantial heritability for BMI and WC (77% for both). Bivariate genetic analyses showed that, although the genetic influence on WC was largely common to BMI (60%), there was also a significant independent genetic effect (40%). For both BMI and WC, there was a very modest shared-environment effect, and the remaining environmental variance was unshared. Conclusions: Genetic influences on BMI and abdominal adiposity are high in children born since the onset of the pediatric obesity epidemic. Most of the genetic effect on abdominal adiposity is common to BMI, but 40% is attributable to independent genetic influences. Environmental effects are small and are divided approximately equally between shared and nonshared effects. Targeting the family may be vital for obesity prevention in the earliest years, but longer-term weight control will require a combination of individual engagement and society-wide efforts to modify the environment, especially for children at high genetic risk.

Math Forum: BEATCALC

2008-02-06T13:29:24-00:00

Andrew McAfee

2008-02-06T10:16:20-00:00

blog.pmarca.com: Silicon Valley after a Microsoft/Yahoo merger: a contrarian view

2008-02-05T10:22:46-00:00

Non-obvious winners and losers in Microsoft Yahoo Deal

2008-02-03T12:48:16-00:00

Keeping Citations Straight, and Finding New Ones :: Inside Higher Ed :: Jobs, News and Views for All of Higher Education

2008-01-31T12:00:21-00:00

Ten simple rules for getting published.

PE Bourne — 2006-02-27T19:00:23-00:00

PLoS Comput Biol, Vol. 1, No. 5. (October 2005)

Using collaborative filtering to weave an information tapestry

David Goldberg — 2006-01-30T21:21:52-00:00

Commun. ACM, Vol. 35, No. 12. (December 1992), pp. 61-70.

Guardian Unlimited | Comment is free | Colin Blakemore on Craig Venter and synthetic life

2008-01-27T12:24:32-00:00

Toward the Next Generation of Recommender Systems: A Survey of the State-of-the-Art and Possible Extensions

G Adomavicius — 2005-04-26T12:49:12-00:00

Knowledge and Data Engineering, IEEE Transactions on, Vol. 17, No. 6. (2005), pp. 734-749.

This paper presents an overview of the field of recommender systems and describes the current generation of recommendation methods that are usually classified into the following three main categories: content-based, collaborative, and hybrid recommendation approaches. This paper also describes various limitations of current recommendation methods and discusses possible extensions that can improve recommendation capabilities and make recommender systems applicable to an even broader range of applications. These extensions include, among others, an improvement of understanding of users and items, incorporation of the contextual information into the recommendation process, support for multcriteria ratings, and a provision of more flexible and less intrusive types of recommendations.

Sex, Science and Profits

Terence Kealey — 2008-01-26T13:49:14-00:00

(17 January 2008)

Why most published research findings are false.

JP Ioannidis — 2005-08-31T19:31:16-00:00

PLoS Med, Vol. 2, No. 8. (August 2005)

SUMMARY: There is increasing concern that most current published research findings are false. The probability that a research claim is true may depend on study power and bias, the number of other studies on the same question, and, importantly, the ratio of true to no relationships among the relationships probed in each scientific field. In this framework, a research finding is less likely to be true when the studies conducted in a field are smaller; when effect sizes are smaller; when there is a greater number and lesser preselection of tested relationships; where there is greater flexibility in designs, definitions, outcomes, and analytical modes; when there is greater financial and other interest and prejudice; and when more teams are involved in a scientific field in chase of statistical significance. Simulations show that for most study designs and settings, it is more likely for a research claim to be false than true. Moreover, for many current scientific fields, claimed research findings may often be simply accurate measures of the prevailing bias. In this essay, I discuss the implications of these problems for the conduct and interpretation of research.

The War of Art: Break Through the Blocks and Win Your Inner Creative Battles

Steven Pressfield — 2007-07-15T14:22:02-00:00

(01 April 2003)

DO YOU: · dream about writing the Great American Novel? · regret not finishing your paintings, poems, or screenplays? · want to start a business or charity? · wish you could start dieting or exercising today? · hope to run a marathon someday? If "yes," then you need…THE WAR OF ART Now, in this powerful, straight-from-the-hip examination of the internal obstacles to success, bestselling author Steven Pressfield shows readers how to identify, defeat, and unlock the inner barriers to creativity. THE WAR OF ART is an inspirational, funny, well-aimed kick in the pants guaranteed to galvanize every would-be artist, visionary, or entrepreneur. Steven Pressfield enjoys great international success as a bestselling novelist. But in order to reach the top he had to do a lot of work to fight the inner demons that told him he couldn't make it. THE WAR OF ART is his challenge to creative block, and his succinct, straight-from-the-hip style will help every reader unleash their personal ambitions, be they literary, artistic, or business-minded. According to Pressfield, the internal obstacle to success is Resistance. Resistance is the difference between the life you lead and the life you want to lead, and can take many forms. Pressfield shows readers how to identify and defeat Resistance at every turn and challenges them to change their amateurish, unsuccessful habits into a professional attitude that can get the job done. Finally, Sun Tzu for the soul! Inspirational, funny, and a great kick in the pants, THE WAR OF ART is the perfect book for anybody who had a goal circumvented by life and circumstance: which is to say, you and everybody you've ever met.

Interview

2008-01-22T08:16:08-00:00

apophenia: The Economist Debate on Social "Networking"

2008-01-21T09:02:14-00:00