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Global Study (global + study)

Distribution by Scientific Domains
Life Sciences50%

Selected Abstracts

Do Insider Trading Laws Work?

EUROPEAN FINANCIAL MANAGEMENT, Issue 3 2005
Arturo Bris
G38; G34; G15 Abstract This paper presents the first comprehensive global study of insider trading laws and their first enforcement. In a sample of 4,541 acquisitions from 52 countries, I find that insider trading enforcement increases both the incidence, and the profitability of insider trading. The expected total insider trading gains increase. Consequently, laws that proscribe insider trading fail to eliminate insider profits. However, harsher laws work better at reducing the incidence of illegal insider trading. [source]

A global study of relationships between leaf traits, climate and soil measures of nutrient fertility

GLOBAL ECOLOGY, Issue 2 2009
Jenny C. Ordoņez
ABSTRACT Aim This first global quantification of the relationship between leaf traits and soil nutrient fertility reflects the trade-off between growth and nutrient conservation. The power of soils versus climate in predicting leaf trait values is assessed in bivariate and multivariate analyses and is compared with the distribution of growth forms (as a discrete classification of vegetation) across gradients of soil fertility and climate. Location All continents except for Antarctica. Methods Data on specific leaf area (SLA), leaf N concentration (LNC), leaf P concentration (LPC) and leaf N:P were collected for 474 species distributed across 99 sites (809 records), together with abiotic information from each study site. Individual and combined effects of soils and climate on leaf traits were quantified using maximum likelihood methods. Differences in occurrence of growth form across soil fertility and climate were determined by one-way ANOVA. Results There was a consistent increase in SLA, LNC and LPC with increasing soil fertility. SLA was related to proxies of N supply, LNC to both soil total N and P and LPC was only related to proxies of P supply. Soil nutrient measures explained more variance in leaf traits among sites than climate in bivariate analysis. Multivariate analysis showed that climate interacted with soil nutrients for SLA and area-based LNC. Mass-based LNC and LPC were determined mostly by soil fertility, but soil P was highly correlated to precipitation. Relationships of leaf traits to soil nutrients were stronger than those of growth form versus soil nutrients. In contrast, climate determined distribution of growth form more strongly than it did leaf traits. Main conclusions We provide the first global quantification of the trade-off between traits associated with growth and resource conservation ,strategies' in relation to soil fertility. Precipitation but not temperature affected this trade-off. Continuous leaf traits might be better predictors of plant responses to nutrient supply than growth form, but growth forms reflect important aspects of plant species distribution with climate. [source]

Proteomics analysis of serous fluids and effusions: Pleural, pericardial, and peritoneal

PROTEOMICS - CLINICAL APPLICATIONS, Issue 8 2007
Yu-Chang Tyan
Abstract Serous body fluids are normally present in small amounts in the cavities lined by serous membranes, and effusions are the term usually used to represent an excess of these fluids. Thus, any changes in the effusions may accurately reflect various pathological processes. In this review, we will introduce the present status of effusion analysis. Proteomics allows the global study of protein expression and offers a comprehensive view to analyze effusion proteins at a system level. It deals with the study of proteins, their structures, localizations, PTM, functions, and interactions with other proteins. This paper reviews the variety of analytical methods that have been used for the analysis of effusions. The proteins expressed in effusions, which have been identified by proteomics methods are discussed. [source]

Phosphonium labeling for increasing metabolomic coverage of neutral lipids using electrospray ionization mass spectrometry,

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2009
Hin-Koon Woo
Mass spectrometry has become an indispensable tool for the global study of metabolites (metabolomics), primarily using electrospray ionization mass spectrometry (ESI-MS). However, many important classes of molecules such as neutral lipids do not ionize well by ESI and go undetected. Chemical derivatization of metabolites can enhance ionization for increased sensitivity and metabolomic coverage. Here we describe the use of tris(2,4,6,-trimethoxyphenyl)phosphonium acetic acid (TMPP-AA) to improve liquid chromatography (LC)/ESI-MS detection of hydroxylated metabolites (i.e. lipids) from serum extracts. Cholesterol which is not normally detected from serum using ESI is observed with attomole sensitivity. This approach was applied to identify four endogenous lipids (hexadecanoyl-sn-glycerol, dihydrotachysterol, octadecanol, and alpha-tocopherol) from human serum. Overall, this approach extends the types of metabolites which can be detected using standard ESI-MS instrumentation and demonstrates the potential for targeted metabolomics analysis. Published in 2009 by John Wiley & Sons, Ltd. [source]