Últimos itens adicionados do Acervo: Harvard University

A Universidade de Harvard (em inglês: Harvard University) é uma universidade privada membro da Ivy League, localizada em Cambridge, Massachusetts, Estados Unidos, e cuja história, influência e riqueza tornam-a uma das mais prestigiadas universidades do mundo.

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Plasma 25-hydroxyvitamin D and risk of premenstrual syndrome in a prospective cohort study

Bertone-Johnson, Elizabeth R; Hankinson, Susan E; Forger, Nancy G; Powers, Sally I; Willett, Walter C; Johnson, Susan R; Manson, JoAnn E
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
EN_US
Background: Moderate to severe premenstrual syndrome (PMS) affects 8–20 percent of premenopausal women. Previous studies suggest that high dietary vitamin D intake may reduce risk. However, vitamin D status is influenced by both dietary vitamin D intake and sunlight exposure and the association of vitamin D status with PMS remains unclear. Methods: We assessed the relation of plasma 25-hydroxyvitamin D (25OHD), total calcium and parathyroid hormone levels with risk of PMS and specific menstrual symptoms in a case–control study nested within the prospective Nurses’ Health Study II. Cases were 401 women free from PMS at baseline who developed PMS during follow-up (1991–2005). Controls were women not experiencing PMS (1991–2005), matched 1:1 with cases on age and other factors. Timed luteal phase blood samples were collected between 1996 and 1999 from cases and controls. We used conditional logistic regression to model the relation of 25OHD levels with risk of PMS and individual menstrual symptoms. Results: In analyses of all cases and controls, 25OHD levels were not associated with risk of PMS. However, results differed when the timing of blood collection vs. PMS diagnosis was considered. Among cases who had already been diagnosed with PMS at the time of blood collection (n = 279)...

A Web-Based Normative Calculator for the Uniform Data Set (UDS) Neuropsychological Test Battery

Shirk, Steven D; Weintraub, Sandra; Mitchell, Meghan B; Shaughnhessy, Lynn W; Sherman, Janet Cohen; Locascio, Joseph J; Atri, Alireza
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
EN_US
Introduction: With the recent publication of new criteria for the diagnosis of preclinical Alzheimer's disease (AD), there is a need for neuropsychological tools that take premorbid functioning into account in order to detect subtle cognitive decline. Using demographic adjustments is one method for increasing the sensitivity of commonly used measures. We sought to provide a useful online z-score calculator that yields estimates of percentile ranges and adjusts individual performance based on sex, age and/or education for each of the neuropsychological tests of the National Alzheimer's Coordinating Center Uniform Data Set (NACC, UDS). In addition, we aimed to provide an easily accessible method of creating norms for other clinical researchers for their own, unique data sets. Methods: Data from 3,268 clinically cognitively-normal older UDS subjects from a cohort reported by Weintraub and colleagues (2009) were included. For all neuropsychological tests, z-scores were estimated by subtracting the raw score from the predicted mean and then dividing this difference score by the root mean squared error term (RMSE) for a given linear regression model. Results: For each neuropsychological test, an estimated z-score was calculated for any raw score based on five different models that adjust for the demographic predictors of SEX...

Takeovers in the '60s and the '80s: Evidence and Implications

Shleifer, Andrei; Vishny, Robert W.
Fonte: John Wiley and Sons Publicador: John Wiley and Sons
Tipo: Artigo de Revista Científica
EN_US
This paper reviews the evidence on takeover waves of the 1960s and 1980s, and discusses the implications of this evidence for corporate strategy, agency theory, capital market efficiency, and antitrust policy. We conclude that antitrust policy played an important role in the two takeover waves, and that the wave of the ';60s presents a problem for efficient capital markets.; Economics

"Making up Your Mind" and the Activity of Reason

Boyle, Matthew
Fonte: University of Michigan Publicador: University of Michigan
Tipo: Artigo de Revista Científica
EN_US
Philosophy

Mining the Web for Medical Hypothesis: A Proof-of-Concept System

Maclean, Diana; Seltzer, Margo I.
Fonte: Harvard University Publicador: Harvard University
Tipo: Monograph or Book
EN_US
As the prevalence of blogs, discussion forums, and online news services continues to grow, so too does the portion of this Web content that relates to health and medicine. We propose that everyday, medically-oriented Web content is a valuable and viable data source for medical hypothesis generation and testing, despite its being noisy. In this paper, we present a proof-of-concept system supporting this notion. We construct a corpus comprising news articles relating to the drugs Vioxx, Naproxen and Ibuprofen, that were published between 1998-2002. Using this corpus, we show that there was a significant link between Vioxx and the concept “Myocardial Infarction” well before the drug was withdrawn from the market in 2004. Indeed, within the Vioxx-related content, the concept ranks amongst the top 3.3% in terms of importance. When compared with the Naproxen and Ibuprofen control literatures, the term occurs significantly more frequently in the Vioxx-related content.; Engineering and Applied Sciences

PlateMate: Crowdsourcing Nutrition Analysis from Food Photographs

Noronha, Jon; Hysen, Eric; Zhang, Haoqi; Gajos, Krzysztof Z.
Fonte: Association for Computing Machinery Publicador: Association for Computing Machinery
Tipo: Monograph or Book
EN_US
We introduce PlateMate, a system that allows users to take photos of their meals and receive estimates of food intake and composition. Accurate awareness of this information can help people monitor their progress towards dieting goals, but current methods for food logging via self-reporting, expert observation, or algorithmic analysis are time-consuming, expensive, or inaccurate. PlateMate crowdsources nutritional analysis from photographs using Amazon Mechanical Turk, automatically coordinating untrained workers to estimate a meal's calories, fat, carbohydrates, and protein. We present the Management framework for crowdsourcing complex tasks, which supports PlateMate's nutrition analysis workflow. Results of our evaluations show that PlateMate is nearly as accurate as a trained dietitian and easier to use for most users than traditional self-reporting.; Engineering and Applied Sciences

Evaluating a Pattern-Based Visual Support Approach for Humanitarian Landmine Clearance

Jayatilaka, Lahiru G.; Bertuccelli, Luca F.; Staszewski, James; Gajos, Krzysztof Z.
Fonte: Association for Computing Machinery Publicador: Association for Computing Machinery
Tipo: Monograph or Book
EN_US
Unexploded landmines have severe post-conflict humanitarian repercussions: landmines cost lives, limbs and land. For deminers engaged in humanitarian landmine clearance, metal detectors remain the primary detection tool as more sophisticated technologies fail to get adopted due to restrictive cost, low reliability, and limited robustness. Metal detectors are, however, of limited effectiveness, as modern landmines contain only minimal amounts of metal, making them difficult to distinguish from the ubiquitous but harmless metallic clutter littering post-combat areas. We seek to improve the safety and efficiency of the demining process by developing support tools that will enable deminers to make better decisions using feedback from existing metal detectors. To this end, in this paper we propose and evaluate a novel, pattern-based visual support approach inspired by the documented strategies employed by expert deminers. In our laboratory study, participants provided with a prototype of our support tool were 80% less likely to mistake a mine for harmless clutter. A follow-up study demonstrates the potential of our pattern-based approach to enable peer decision-making support during landmine clearance. Lastly, we identify several design opportunities for further improving deminers' decision making capabilities.; Engineering and Applied Sciences

Free Offline Access: A Primer on OA' (OA Prime)

Suber, Peter
Fonte: Scholarly Publishing and Academic Resources Coalition Publicador: Scholarly Publishing and Academic Resources Coalition
Tipo: Artigo de Revista Científica
EN_US

Crucial role of calbindin-D28k in the pathogenesis of Alzheimer's disease mouse model

Kook, S-Y; Jeong, H; Kang, M J; Park, R; Shin, H J; Han, S-H; Son, S M; Song, H; Baik, S H; Moon, M; Yi, E C; Hwang, D; Mook-Jung, I
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
EN_US
Calbindin-D28k (CB), one of the major calcium-binding and buffering proteins, has a critical role in preventing a neuronal death as well as maintaining calcium homeostasis. Although marked reductions of CB expression have been observed in the brains of mice and humans with Alzheimer disease (AD), it is unknown whether these changes contribute to AD-related dysfunction. To determine the pathogenic importance of CB depletions in AD models, we crossed 5 familial AD mutations (5XFAD; Tg) mice with CB knock-out (CBKO) mice and generated a novel line CBKO·5XFAD (CBKOTg) mice. We first identified the change of signaling pathways and differentially expressed proteins globally by removing CB in Tg mice using mass spectrometry and antibody microarray. Immunohistochemistry showed that CBKOTg mice had significant neuronal loss in the subiculum area without changing the magnitude (number) of amyloid β-peptide (Aβ) plaques deposition and elicited significant apoptotic features and mitochondrial dysfunction compared with Tg mice. Moreover, CBKOTg mice reduced levels of phosphorylated mitogen-activated protein kinase (extracellular signal-regulated kinase) 1/2 and cAMP response element-binding protein at Ser-133 and synaptic molecules such as N-methyl-D-aspartate receptor 1 (NMDA receptor 1)...

Innovation and Access to Medicines for Neglected Populations: Could a Treaty Address a Broken Pharmaceutical R&D System?

Bermudez, Jorge; 't Hoen, Ellen; Moon, Suerie
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN_US
As part of a cluster of articles leading up to the 2012 World Health Report and critically reflecting on the theme of “no health without research,” Suerie Moon and colleagues argue for a global health R&D treaty to improve innovation in new medicines and strengthening affordability, sustainable financing, efficiency in innovation, and equitable health-centered governance.

Evaluating the Impact of Patients' Online Access to Doctors' Visit Notes: Designing and Executing the OpenNotes Project

Ralston, James D; Ross, Stephen E; Elmore, Joann G; Delbanco, Tom; Leveille, Suzanne G.; Walker, Janice D.
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
EN_US
Background: Providers and policymakers are pursuing strategies to increase patient engagement in health care. Increasingly, online sections of medical records are viewable by patients though seldom are clinicians' visit notes included. We designed a one-year multi-site trial of online patient accessible office visit notes, OpenNotes. We hypothesized that patients and primary care physicians (PCPs) would want it to continue and that OpenNotes would not lead to significant disruptions to doctors' practices. Methods/Design: Using a mixed methods approach, we designed a quasi-experimental study in 3 diverse healthcare systems in Boston, Pennsylvania, and Seattle. Two sites had existing patient internet portals; the third used an experimental portal. We targeted 3 key areas where we hypothesized the greatest impacts: beliefs and attitudes about OpenNotes, use of the patient internet portals, and patient-doctor communication. PCPs in the 3 sites were invited to participate in the intervention. Patients who were registered portal users of participating PCPs were given access to their PCPs' visit notes for one year. PCPs who declined participation in the intervention and their patients served as the comparison groups for the study. We applied the RE-AIM framework to our design in order to capture as comprehensive a picture as possible of the impact of OpenNotes. We developed pre- and post-intervention surveys for online administration addressing attitudes and experiences based on interviews and focus groups with patients and doctors. In addition...

Correlation of Renin Angiotensin and Aldosterone System Activity with Subcutaneous and Visceral Adiposity: The Framingham Heart Study

Hwang, Shih-Jen; Vasan, Ramachandran S; Larson, Martin G; O'Seaghdha, Conall M.; Hoffmann, Udo; Wang, Thomas Jue-Fuu; Fox, Caroline
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
EN_US
Background: Animal studies suggest that local adipocyte-mediated activity of the renin-angiotensin-aldosterone system (RAAS) contributes to circulating levels, and may promote the development of obesity-related hypertension in rodents. Methods: We examined relations of systemic RAAS activity, as assessed by circulating plasma renin activity (PRA), serum aldosterone level, and aldosterone:renin ratio (ARR), with specific regional adiposity measures in a large, community-based sample. Third Generation Framingham Heart Study participants underwent multidetector computed tomography assessment of SAT and VAT volumes during Exam 1 (2002 and 2005). PRA and serum aldosterone were measured after approximately 10 minutes of supine rest; results were log-transformed for analysis. Correlation coefficients between log-transformed RAAS measures and adiposity measurements were calculated, adjusted for age and sex. Partial correlations between log-transformed RAAS measures and adiposity measurements were also calculated, adjusted for standard CVD risk factors. Results: Overall, 992 women and 897 men were analyzed (mean age 40 years; 7% hypertension; 3% diabetes). No associations were observed with SAT (renin r = 0.04, p = 0.1; aldosterone r = -0.01...

Discovery of Catalytically Active Orthologues of the Parkinson's Disease Kinase PINK1: Analysis of Substrate Specificity and Impact of Mutations

Woodroof, Helen I.; Pogson, Joe H.; Begley, Mike; Deak, Maria; van Aalten, Daan M. F.; Whitworth, Alexander J.; Alessi, Dario R.; Muqit, Miratul M. K.; Cantley, Lewis C.; Campbell, David G.
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
EN_US
Missense mutations of the phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1) gene cause autosomal-recessive Parkinson's disease. To date, little is known about the intrinsic catalytic properties of PINK1 since the human enzyme displays such low kinase activity in vitro. We have discovered that, in contrast to mammalian PINK1, insect orthologues of PINK1 we have investigated—namely Drosophila melanogaster (dPINK1), Tribolium castaneum (TcPINK1) and Pediculus humanus corporis (PhcPINK1)—are active as judged by their ability to phosphorylate the generic substrate myelin basic protein. We have exploited the most active orthologue, TcPINK1, to assess its substrate specificity and elaborated a peptide substrate (PINKtide, KKWIpYRRSPRRR) that can be employed to quantify PINK1 kinase activity. Analysis of PINKtide variants reveal that PINK1 phosphorylates serine or threonine, but not tyrosine, and we show that PINK1 exhibits a preference for a proline at the +1 position relative to the phosphorylation site. We have also, for the first time, been able to investigate the effect of Parkinson's disease-associated PINK1 missense mutations, and found that nearly all those located within the kinase domain, as well as the C-terminal non-catalytic region...

'Sharing Nicely': On Shareable Goods and the Emergence of Sharing as a Modality of Economic Production

Benkler, Yochai
Fonte: Yale Law School Publicador: Yale Law School
Tipo: Artigo de Revista Científica
EN_US
The world's fastest supercomputer and the second-largest commuter transportation system in the United States function on a resource- management model that is not well specified in contemporary economics. Both SETI@home, a distributed computing platform involving the computers of over four million volunteers, and carpooling, which accounts for roughly one-sixth of commuting trips in the United States, rely on social relations and an ethic of sharing, rather than on a price system, to mobilize and allocate resources. Yet they coexist with, and outperform, price-based and government-funded systems that offer substitutable functionality. Neither practice involves public goods, network goods, or any other currently defined category of economically "quirky" goods as either inputs or outputs. PCs and automobiles are privately owned, rival goods, with no obvious demand-side positive returns to scale when used for distributed computing or carpooling. The sharing practices that have evolved around them are not limited to tightly knit communities of repeat players who know each other well and interact across many contexts. They represent instances where social sharing is either utterly impersonal or occurs among loosely affiliated individuals who engage in social practices that involve contributions of the capacity of their private goods in patterns that combine to form large-scale and effective systems for provisioning goods...

Coase's Penguin, or, Linux and The Nature of the Firm

Benkler, Yochai
Fonte: Yale Law School Publicador: Yale Law School
Tipo: Artigo de Revista Científica
EN_US
For decades our common understanding of the organization of economic production has been that individuals order their productive activities in one of two ways: either as employees in firms, following the directions of managers, or as individuals in markets, following price signals. This dichotomy was first identified in the early work of Ronald Coase and was developed most explicitly in the work of institutional economist Oliver Williamson. Recently, public attention has focused on a fifteen-year-old phenomenon called free software or open source software. This phenomenon involves thousands, or even tens of thousands, of computer programmers who collaborate on large- and small-scale projects without traditional firm-based or market-based ownership of the resulting product. This Article explains why free software is only one example of a much broader social-economic phenomenon emerging in the digitally networked environment, a third mode of production that the author calls "commons-based peer production." The Article begins by demonstrating the widespread use of commons-based peer production on the Internet through a number of detailed examples, such as Wikipedia, Slashdot, the Open Directory Project, and Google. The Article uses these examples to reveal fundamental characteristics of commons-based peer production that distinguish it from the property- and contract-based modes of firms and markets. The central distinguishing characteristic is that groups of individuals successfully collaborate on large-scale projects following a diverse cluster of motivational drives and social signals rather than market prices or managerial commands. The Article then explains why this mode has systematic advantages over markets and managerial hierarchies in the digitally networked environment when the object of production is information or culture. First...

Intellectual Property and the Organization of Information Production

Benkler, Yochai
Fonte: Elsevier Science Publicador: Elsevier Science
Tipo: Artigo de Revista Científica
EN_US
This paper analyzes an area that economic analysis of intellectual property has generally ignored, namely, the effects of intellectual property rights on the relative desirability of various strategies for organizing information production. I suggest that changes in intellectual property rules alter the payoffs to information production in systematic and predictable ways that differ as among different strategies. My conclusion is that an institutional environment highly protective of intellectual property rights will (a) have less beneficial impact, at an aggregate level, than one would predict without considering these effects, and (b) fosters commercialization, concentration, and homogenization of information production, and thus entails normative implications that may be more salient than its quantitative effects.

The Transformation of a Social Movement into Law?: The SCLC and NAACP's Campaigns for Civil Rights Reconsidered In Light of the Educational Activism of Septima Clark

Brown-Nagin, Tomiko
Fonte: Routledge Journals, Taylor & Francis Publicador: Routledge Journals, Taylor & Francis
Tipo: Artigo de Revista Científica
EN_US
This article reconsiders the efficacy of the Southern Christian Leadership Conference's (SCLC) and the National Association for the Advancement of Colored People's (NAACP's) strategies for achieving civil rights by comparing and contrasting them to the approach favored by the educator, Septima Poinsette Clark. Focusing on the relationship between literacy and the ability of individuals to achieve political and socio-economic power, Clark argued that knowledge could empower marginalized groups in ways that formal legal equality could not. Although her educational activism inlocal communities was important to the overall success of the civil rights movement, Clark is a relatively obscure historical figure; her value to the movement was underappreciated by more prominent male leaders due to gender inequality, she believed. Whatever its origins, this failure fully to appreciate the worth of activists of Clark's caliber was mistaken, this article concludes. Inattenton to the perspectives of those with educational expertise significantly undermined the overall efficacy of the NAACP's and SCLC's endeavors to achieve racial equality by compelling compliance with constitutional norms, especially with respect to the great number of abjectly impoverished people who were intended beneficiaries of their work

Constitutional Lawyering in the 21st Century

Clark, Robert C.
Fonte: Students at Brooklyn Law School Publicador: Students at Brooklyn Law School
Tipo: Artigo de Revista Científica
EN_US

Bases and Prospects for Internationalization of Legal Education in the United States

Clark, Robert C.
Fonte: Dickinson School of Law Publicador: Dickinson School of Law
Tipo: Artigo de Revista Científica
EN_US

The Trouble with Staggered Boards: A Reply to Georgeson's John Wilcox

Bebchuk, Lucian Arye; Coates, John; Subramanian, Guhan
Fonte: Prentice Hall Law & Business Publicador: Prentice Hall Law & Business
Tipo: Artigo de Revista Científica
EN_US
In recent work, we presented evidence indicating that staggered boards have adverse effects on target shareholders. John Wilcox, the Vice-Chair of Georgeson, recently published a critique of our work, urging shareholders to support staggered boards. We respond in this article to Wilcox's critique and explain why it does not weaken in any way our analysis of staggered boards. The study criticized by Wilcox, "The Powerful Antitakeover Force of Staggered Boards: Theory, Evidence, and Policy," 54 Stanford Law Review 887-951 (2002), is available at http://ssrn.com/abstract=304388. In a separate reply, "The Powerful Antitakeover Force of Staggered Boards: Further Findings and a Reply to Symposium Participants," 55 Stanford Law Review 885-917 (2002), which is available at http://ssrn.com/abstract=360840, we respond to several other responses to our original study and present additional evidence that confirms its conclusions.