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Showing papers by "Stockholm University published in 2008"




Journal ArticleDOI
05 Jun 2008-Nature
TL;DR: It is shown that adipocyte number is a major determinant for the fat mass in adults, however, the number of fat cells stays constant in adulthood in lean and obese individuals, even after marked weight loss, indicating that thenumber of adipocytes is set during childhood and adolescence.
Abstract: Obesity is increasing in an epidemic manner in most countries and constitutes a public health problem by enhancing the risk for cardiovascular disease and metabolic disorders such as type 2 diabetes. Owing to the increase in obesity, life expectancy may start to decrease in developed countries for the first time in recent history. The factors determining fat mass in adult humans are not fully understood, but increased lipid storage in already developed fat cells (adipocytes) is thought to be most important. Here we show that adipocyte number is a major determinant for the fat mass in adults. However, the number of fat cells stays constant in adulthood in lean and obese individuals, even after marked weight loss, indicating that the number of adipocytes is set during childhood and adolescence. To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analysing the integration of 14C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index. Neither adipocyte death nor generation rate is altered in early onset obesity, suggesting a tight regulation of fat cell number in this condition during adulthood. The high turnover of adipocytes establishes a new therapeutic target for pharmacological intervention in obesity.

2,098 citations


Journal ArticleDOI
TL;DR: The magnitude of species-driven differences is much larger than previously thought and greater than climate-driven variation, and the decomposability of a species' litter is consistently correlated with that species' ecological strategy within different ecosystems globally, representing a new connection between whole plant carbon strategy and biogeochemical cycling.
Abstract: Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as litter quality. To quantify the degree to which functional differentiation among species affects their litter decomposition rates, we brought together leaf trait and litter mass loss data for 818 species from 66 decomposition experiments on six continents. We show that: (i) the magnitude of species-driven differences is much larger than previously thought and greater than climate-driven variation; (ii) the decomposability of a species' litter is consistently correlated with that species' ecological strategy within different ecosystems globally, representing a new connection between whole plant carbon strategy and biogeochemical cycling. This connection between plant strategies and decomposability is crucial for both understanding vegetation-soil feedbacks, and for improving forecasts of the global carbon cycle.

1,935 citations


Journal ArticleDOI
TL;DR: A new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to work with these heterogeneous compilations is presented in this article.
Abstract: We present a new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to work with these heterogeneous compilations This "Union" compilation of 414 SNe Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and ESSENCE Survey, the older data sets, as well as the recently extended data set of distant supernovae observed with the Hubble Space Telescope (HST) A single, consistent, and blind analysis procedure is used for all the various SN Ia subsamples, and a new procedure is implemented that consistently weights the heterogeneous data sets and rejects outliers We present the latest results from this Union compilation and discuss the cosmological constraints from this new compilation and its combination with other cosmological measurements (CMB and BAO) The constraint we obtain from supernovae on the dark energy density is ΩΛ = 0713+ 0027−0029(stat)+ 0036−0039(sys) , for a flat, ΛCDM universe Assuming a constant equation of state parameter, w, the combined constraints from SNe, BAO, and CMB give w = − 0969+ 0059−0063(stat)+ 0063−0066(sys) While our results are consistent with a cosmological constant, we obtain only relatively weak constraints on a w that varies with redshift In particular, the current SN data do not yet significantly constrain w at z > 1 With the addition of our new nearby Hubble-flow SNe Ia, these resulting cosmological constraints are currently the tightest available

1,420 citations


Journal ArticleDOI
TL;DR: The LEDA Traitbase is useful for large-scale analyses of functional responses of communities to environmental change, effects of community trait composition on ecosystem properties and patterns of rarity and invasiveness, as well as linkages between traits as expressions of fundamental trade-offs in plants.
Abstract: Summary 1. An international group of scientists has built an open internet data base of life-history traits of the Northwest European flora (the LEDA-Traitbase) that can be used as a data source for fundamental research on plant biodiversity and coexistence, macro-ecological patterns and plant functional responses. 2. The species-trait matrix comprises referenced information under the control of an editorial board, for ca. 3000 species of the Northwest European flora, combining existing information and additional measurements. The data base currently contains data on 26 plant traits that describe three key features of plant dynamics: persistence, regeneration and dispersal. The LEDA-Traitbase is freely available at www.leda-traitbase.org. 3. We present the structure of the data base and an overview of the trait information available. 4. Synthesis. The LEDA Traitbase is useful for large-scale analyses of functional responses of communities to environmental change, effects of community trait composition on ecosystem properties and patterns of rarity and invasiveness, as well as linkages between traits as expressions of fundamental trade-offs in plants.

1,379 citations


Journal ArticleDOI
TL;DR: The use of coupled catalytic systems with electron-transfer mediators usually facilitates the procedures by transporting the electrons from the catalyst to the oxidant along a low-energy pathway, thereby increasing the efficiency of the oxidation and thus complementing the direct oxidation reactions.
Abstract: Oxidation reactions are of fundamental importance in nature, and are key transformations in organic synthesis. The development of new processes that employ transition metals as substrate-selective catalysts and stoichiometric environmentally friendly oxidants, such as molecular oxygen or hydrogen peroxide, is one of the most important goals in oxidation chemistry. Direct oxidation of the catalyst by molecular oxygen or hydrogen peroxide is often kinetically unfavored. The use of coupled catalytic systems with electron-transfer mediators (ETMs) usually facilitates the procedures by transporting the electrons from the catalyst to the oxidant along a low-energy pathway, thereby increasing the efficiency of the oxidation and thus complementing the direct oxidation reactions. As a result of the similarities with biological systems, this can be dubbed a biomimetic approach.

764 citations


Journal ArticleDOI
01 Aug 2008-Science
TL;DR: A northern shift of the Intertropical Convergence Zone could be the trigger of these abrupt shifts of Northern Hemisphere atmospheric circulation, resulting in changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next.
Abstract: The last two abrupt warmings at the onset of our present warm interglacial period, interrupted by the Younger Dryas cooling event, were investigated at high temporal resolution from the North Greenland Ice Core Project ice core. The deuterium excess, a proxy of Greenland precipitation moisture source, switched mode within 1 to 3 years over these transitions and initiated a more gradual change (over 50 years) of the Greenland air temperature, as recorded by stable water isotopes. The onsets of both abrupt Greenland warmings were slightly preceded by decreasing Greenland dust deposition, reflecting the wetting of Asian deserts. A northern shift of the Intertropical Convergence Zone could be the trigger of these abrupt shifts of Northern Hemisphere atmospheric circulation, resulting in changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next.

734 citations


Journal ArticleDOI
TL;DR: There is growing research interest in the ethnobiology, socio-economics and management of mangrove forests as discussed by the authors, with harvesting efforts and impacts concentrated in stands that are closer to settlements and easiest to access (by land or by sea).

687 citations


Journal ArticleDOI
TL;DR: Correlations were observed in the MCI patients between PIB retention and CSF Abeta(1-42), total Tau and episodic memory, respectively, and the P IB retention in MCI converters was comparable to AD patients.

686 citations


Journal ArticleDOI
23 Apr 2008-PLOS ONE
TL;DR: This study provides the most comprehensive chloroplast proteome analysis to date and an expanded Plant Proteome Database (PPDB) in which all MS data are projected on identified gene models.
Abstract: Characterization of the chloroplast proteome is needed to understand the essential contribution of the chloroplast to plant growth and development. Here we present a large scale analysis by nanoLC-Q-TOF and nanoLC-LTQ-Orbitrap mass spectrometry (MS) of ten independent chloroplast preparations from Arabidopsis thaliana which unambiguously identified 1325 proteins. Novel proteins include various kinases and putative nucleotide binding proteins. Based on repeated and independent MS based protein identifications requiring multiple matched peptide sequences, as well as literature, 916 nuclear-encoded proteins were assigned with high confidence to the plastid, of which 86% had a predicted chloroplast transit peptide (cTP). The protein abundance of soluble stromal proteins was calculated from normalized spectral counts from LTQ-Obitrap analysis and was found to cover four orders of magnitude. Comparison to gel-based quantification demonstrates that 'spectral counting' can provide large scale protein quantification for Arabidopsis. This quantitative information was used to determine possible biases for protein targeting prediction by TargetP and also to understand the significance of protein contaminants. The abundance data for 550 stromal proteins was used to understand abundance of metabolic pathways and chloroplast processes. We highlight the abundance of 48 stromal proteins involved in post-translational proteome homeostasis (including aminopeptidases, proteases, deformylases, chaperones, protein sorting components) and discuss the biological implications. N-terminal modifications were identified for a subset of nuclear- and chloroplast-encoded proteins and a novel N-terminal acetylation motif was discovered. Analysis of cTPs and their cleavage sites of Arabidopsis chloroplast proteins, as well as their predicted rice homologues, identified new species-dependent features, which will facilitate improved subcellular localization prediction. No evidence was found for suggested targeting via the secretory system. This study provides the most comprehensive chloroplast proteome analysis to date and an expanded Plant Proteome Database (PPDB) in which all MS data are projected on identified gene models.


Journal ArticleDOI
TL;DR: It is recommended recognizing that some genetic change due to harvest is inevitable and management plans should be developed by applying basic genetic principles combined with molecular genetic monitoring to minimize harmful genetic change.
Abstract: Human harvest of animals in the wild occurs in terrestrial and aquatic habitats throughout the world and is often intense. Harvest has the potential to cause three types of genetic change: alteration of population subdivision, loss of genetic variation, and selective genetic changes. To sustain the productivity of harvested populations, it is crucial to incorporate genetic considerations into management. Nevertheless, it is not necessary to disentangle genetic and environmental causes of phenotypic changes to develop management plans for individual species. We recommend recognizing that some genetic change due to harvest is inevitable. Management plans should be developed by applying basic genetic principles combined with molecular genetic monitoring to minimize harmful genetic change.

Journal ArticleDOI
TL;DR: In this paper, the authors extend the applicability of governance theory by developing hypotheses about how different governance types can be expected to handle processes of change characterized by nonlinear dynamics, threshold effects, cascades, and limited predictability.
Abstract: Unexpected epidemics, abrupt catastrophic shifts in biophysical systems, and economic crises that cascade across national borders and regions are events that challenge the steering capacity of governance at all political levels. This article seeks to extend the applicability of governance theory by developing hypotheses about how different governance types can be expected to handle processes of change characterized by nonlinear dynamics, threshold effects, cascades, and limited predictability. The first part of the article argues the relevance of a complex adaptive system approach and goes on to review how well governance theory acknowledges the intriguing behavior of complex adaptive systems. In the second part, we develop a typology of governance systems based on their adaptive capacities. Finally, we investigate how combinations of governance systems on different levels buffer or weaken the capacity to govern complex adaptive systems.

Journal ArticleDOI
03 Jan 2008-Nature
TL;DR: Examining the vertical structure of temperature change in the Arctic during the late twentieth century using reanalysis data finds evidence for temperature amplification well above the surface, and concludes that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification.
Abstract: Near-surface warming in the Arctic has been almost twice as large as the global average over recent decades1, 2, 3, 4, 5—a phenomenon that is known as the 'Arctic amplification'. The underlying cau ...

Journal ArticleDOI
TL;DR: In this paper, the penumbral fine structure in a small part of a pore, observed with the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope (SST), close to its diffraction limit of 0.16''.
Abstract: We discuss penumbral fine structure in a small part of a pore, observed with the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope (SST), close to its diffraction limit of 0.16''. Milne-Eddington inversions applied to these Stokes data reveal large variations of field strength and inclination angle over dark-cored penumbral intrusions and a dark-cored light bridge. The mid-outer part of this penumbra structure shows ~0.3'' wide spines, separated by ~1.6'' (1200 km) and associated with 30° inclination variations. Between these spines, there are no small-scale magnetic structures that easily can be identified with individual flux tubes. A structure with nearly 10° more vertical and weaker magnetic field is seen midway between two spines. This structure is cospatial with the brightest penumbral filament, possibly indicating the location of a convective upflow from below.

Journal ArticleDOI
TL;DR: In this article, an overview of the various measurement techniques, related difficulties, and limitations of data interpretation; describe spatial characteristics of East Antarctic SMB and issues related to the spatial and temporal representativity of measurements; and provide recommendations on how to perform in situ measurements.
Abstract: The East Antarctic Ice Sheet is the largest, highest, coldest, driest, and windiest ice sheet on Earth. Understanding of the surface mass balance (SMB) of Antarctica is necessary to determine the present state of the ice sheet, to make predictions of its potential contribution to sea level rise, and to determine its past history for paleoclimatic reconstructions. However, SMB values are poorly known because of logistic constraints in extreme polar environments, and they represent one of the biggest challenges of Antarctic science. Snow accumulation is the most important parameter for the SMB of ice sheets. SMB varies on a number of scales, from small-scale features (sastrugi) to ice-sheet-scale SMB patterns determined mainly by temperature, elevation, distance from the coast, and wind-driven processes. In situ measurements of SMB are performed at single points by stakes, ultrasonic sounders, snow pits, and firn and ice cores and laterally by continuous measurements using ground-penetrating radar. SMB for large regions can only be achieved practically by using remote sensing and/or numerical climate modeling. However, these techniques rely on ground truthing to improve the resolution and accuracy. The separation of spatial and temporal variations of SMB in transient regimes is necessary for accurate interpretation of ice core records. In this review we provide an overview of the various measurement techniques, related difficulties, and limitations of data interpretation; describe spatial characteristics of East Antarctic SMB and issues related to the spatial and temporal representativity of measurements; and provide recommendations on how to perform in situ measurements.

Journal ArticleDOI
Joshua A. Frieman1, Joshua A. Frieman2, Bruce A. Bassett3, Andrew C. Becker4, Changsu Choi5, D. Cinabro6, F. DeJongh1, Darren L. DePoy7, Ben Dilday2, Mamoru Doi8, Peter M. Garnavich9, Craig J. Hogan4, Jon A. Holtzman10, Myungshin Im5, Saurabh Jha11, Richard Kessler2, Kohki Konishi8, Hubert Lampeitl12, John Marriner1, Jennifer L. Marshall7, D. McGinnis1, G. Miknaitis1, Robert C. Nichol13, J. L. Prieto7, Adam G. Riess12, Adam G. Riess14, Michael Richmond15, Roger W. Romani11, Masao Sako16, Donald P. Schneider17, Mathew Smith13, Naohiro Takanashi8, Kouichi Tokita8, Kurt van der Heyden, Naoki Yasuda8, Chen Zheng11, Jennifer K. Adelman-McCarthy1, James Annis1, Roberto J. Assef7, J. C. Barentine18, J. C. Barentine19, Ralf Bender20, Roger Blandford11, William N. Boroski1, Malcolm N. Bremer21, Howard Brewington18, Chris A. Collins22, Arlin P. S. Crotts23, Jack Dembicky18, Jason D. Eastman7, Alastair C. Edge24, Edmond Edmondson13, Edward C. Elson, Michael E. Eyler25, Alexei V. Filippenko26, Ryan J. Foley26, Stephan Frank7, Ariel Goobar27, Tina Gueth10, James E. Gunn28, Michael Harvanek18, Michael Harvanek29, Ulrich Hopp20, Yutaka Ihara8, Želko Ivezić4, Steven M. Kahn11, Jared Kaplan30, Stephen B. H. Kent1, Stephen B. H. Kent2, William Ketzeback18, S. J. Kleinman31, S. J. Kleinman18, Wolfram Kollatschny32, Richard G. Kron2, Jurek Krzesinski18, D. Lamenti33, Giorgos Leloudas34, Huan Lin1, Dan Long18, John R. Lucey24, Robert H. Lupton28, Elena Malanushenko18, Viktor Malanushenko18, Russet McMillan18, Javier Méndez35, Christopher W. Morgan25, Christopher W. Morgan7, Tomoki Morokuma8, Atsuko Nitta18, Linda Ostman27, Kaike Pan18, Constance M. Rockosi36, A. Kathy Romer37, Pilar Ruiz-Lapuente35, G. Saurage18, K. Schlesinger7, Stephanie A. Snedden18, Jesper Sollerman34, Jesper Sollerman27, Chris Stoughton1, Maximilian Stritzinger34, Mark SubbaRao2, Douglas L. Tucker1, Petri Väisänen, Linda C. Watson7, S. Watters18, J. Craig Wheeler19, Brian Yanny1, Donald G. York2 
TL;DR: The Sloan Digital Sky Survey-II (SDSS-II) as mentioned in this paper is a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band imaging over an area of 300 sq. deg.
Abstract: The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5° wide centered on the celestial equator in the Southern Galactic Cap that has been imaged numerous times in earlier years, enabling construction of a deep reference image for the discovery of new objects. Supernova imaging observations are being acquired between September 1 and November 30 of 2005-7. During the first two seasons, each region was imaged on average every five nights. Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a large number of telescopes. In its first two three-month seasons, the survey has discovered and measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c, 32 confirmed SNe II, plus a large number of photometrically identified SNe Ia, 94 of which have host-galaxy spectra taken so far. This paper provides an overview of the project and briefly describes the observations completed during the first two seasons of operation.

Journal ArticleDOI
TL;DR: In this paper, a new version of the International Bathymetric Chart of the Arctic Ocean (IBCAO) is presented in the form of a digital grid on a Polar Stereographic projection with grid cell spacing of 2 × 2 km.
Abstract: [1] A digital representation of ocean floor topography is essential for a broad variety of geological, geophysical and oceanographic analyses and modeling. In this paper we present a new version of the International Bathymetric Chart of the Arctic Ocean (IBCAO) in the form of a digital grid on a Polar Stereographic projection with grid cell spacing of 2 × 2 km. The new IBCAO, which has been derived from an accumulated database of available bathymetric data including the recent years of multibeam mapping, significantly improves our portrayal of the Arctic Ocean seafloor.

Journal ArticleDOI
TL;DR: In this paper, a major product of organic matter decomposition in lakes, Methane (CH4) represents a major contribution of organic decomposition. Once produced in the sediments, CH4 can be either oxidized or emitted as a greenhouse gas to the atmosphere.
Abstract: Methane (CH4) represents a major product of organic matter decomposition in lakes. Once produced in the sediments, CH4 can be either oxidized or emitted as a greenhouse gas to the atmosphere. Lakes ...

Journal ArticleDOI
01 Jul 2008-Tellus B
TL;DR: In this article, the authors summarized the existing published H-TDMA results on the size-resolved submicrometre aerosol particle hygroscopic properties obtained from ground-based measurements at multiple marine, rural, urban and free tropospheric measurement sites.
Abstract: The hygroscopic properties play a vital role for the direct and indirect effects of aerosols on climate, as well as the health effects of particulate matter (PM) by modifying the deposition pattern of inhaled particles in the humid human respiratory tract. Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA) instruments have been used in field campaigns in various environments globally over the last 25 yr to determine the water uptake on submicrometre particles at subsaturated conditions. These investigations have yielded valuable and comprehensive information regarding the particle hygroscopic properties of the atmospheric aerosol, including state of mixing. These properties determine the equilibrium particle size at ambient relative humidities and have successfully been used to calculate the activation of particles at water vapour supersaturation. This paper summarizes the existing published H-TDMA results on the size-resolved submicrometre aerosol particle hygroscopic properties obtained from ground-based measurements at multiple marine, rural, urban and free tropospheric measurement sites. The data is classified into groups of hygroscopic growth indicating the external mixture, and providing clues to the sources and processes controlling the aerosol. An evaluation is given on how different chemical and physical properties affect the hygroscopic growth.

Journal ArticleDOI
TL;DR: This article used data from the first round of the European Social Survey (2003) involving six West European countries (Austria,Belgium, Denmark, France, the Netherlands and Norway) and found that immigration scepticism is among the principal factors for predicting who will vote for a radical right-wing party.
Abstract: Given how central the immigration issue has been for the new radical right-wing parties in Western Europe, many have turned to immigration-related factors in trying to explain their emergence and electoral mobilisation. This research has convincingly shown that immigration scepticism (i.e., wanting to reduce immigration) is among the principal factors for predicting who will vote for a radical right-wing party. However, earlier studies have often uncritically equated immigration scepticism with xenophobia or even racism. By using data from the first round of the European Social Survey (2003) involving six West European countries (Austria,Belgium,Denmark,France,the Netherlands and Norway),this article differentiates between immigration scepticism and xenophobic attitudes. The analy- ses strongly indicate that xenophobic attitudes are a far less significant factor than immigra- tion scepticism for predicting who will vote for the new radical right. Moreover, this article analyses the extent to which anti-immigration frames employed by radical right-wing parties resonate with attitudes held by supporting voters,and to what extent they make a difference for people's decision to vote for the radical right.The analyses indicate that frames linking immigration to criminality and social unrest are particularly effective for mobilising voter support for the radical right. Finally, the article criticises earlier research that explained radical right-wing voting with reference to ethnic competition theory.In contrast to much of the earlier research that used macro-level measures and comparisons, this study uses (self- reported) individual-level data on the degree of ethnic heterogeneity of people's area of residence. Hypotheses derived from ethnic competition theory receive less support than expected, which indicates that earlier research may have overestimated the significance of these factors.

Journal ArticleDOI
TL;DR: A derivative strain of E. coli BL21(DE3) is engineered, termed Lemo21(de3), in which the activity of the T7 RNA polymerase can be precisely controlled by its natural inhibitor T7 lysozyme (T7Lys), which allows optimizing overexpression of any given membrane protein by using only a single strain rather than a multitude of different strains.
Abstract: A simple generic method for optimizing membrane protein overexpression in Escherichia coli is still lacking. We have studied the physiological response of the widely used “Walker strains” C41(DE3) and C43(DE3), which are derived from BL21(DE3), to membrane protein overexpression. For unknown reasons, overexpression of many membrane proteins in these strains is hardly toxic, often resulting in high overexpression yields. By using a combination of physiological, proteomic, and genetic techniques we have shown that mutations in the lacUV5 promoter governing expression of T7 RNA polymerase are key to the improved membrane protein overexpression characteristics of the Walker strains. Based on this observation, we have engineered a derivative strain of E. coli BL21(DE3), termed Lemo21(DE3), in which the activity of the T7 RNA polymerase can be precisely controlled by its natural inhibitor T7 lysozyme (T7Lys). Lemo21(DE3) is tunable for membrane protein overexpression and conveniently allows optimizing overexpression of any given membrane protein by using only a single strain rather than a multitude of different strains. The generality and simplicity of our approach make it ideal for high-throughput applications.

Journal ArticleDOI
TL;DR: In this paper, the authors argue that the marketing concept and customer-centricity are too limited as a foundation for marketing and have not yet been implemented in practice, and they advocate a network-based stakeholder approach, e.g., many-to-many marketing.
Abstract: This is a contribution to the reorientation of marketing. It aligns the service-dominant logic with other developments in marketing and management. It claims that the marketing concept and customer-centricity are too limited as a foundation for marketing and have not—and cannot—but partially be implemented in practice. It urges marketing scholars and educators to accept the complexity of marketing and develop and teach a network-based stakeholder approach—balanced centricity—epitomized by the concept of many-to-many marketing.

Journal ArticleDOI
TL;DR: The chemical properties of sea spray aerosol particles produced by artificially generated bubbles using oceanic waters were investigated during a phytoplankton bloom in the North Atlantic.
Abstract: The chemical properties of sea-spray aerosol particles produced by artificially generated bubbles using oceanic waters were investigated during a phytoplankton bloom in the North Atlantic. Spray pa ...

Posted ContentDOI
TL;DR: In this article, the structural properties of friendship networks affect individual outcomes in education and the authors developed a model that shows that the outcome of each individual embedded in a network is proportional to her Katz-Bonacich centrality measure.
Abstract: This paper studies whether structural properties of friendship networks affect individual outcomes in education. We first develop a model that shows that, at the Nash equilibrium, the outcome of each individual embedded in a network is proportional to her Katz-Bonacich centrality measure. This measure takes into account both direct and indirect friends of each individual but puts less weight to her distant friends. We then bring the model to the data by using a very detailed dataset of adolescent friendship networks. We show that, after controlling for observable individual characteristics and unobservable network specific factors, the individual's position in a network (as measured by her Katz-Bonacich centrality) is a key determinant of her level of activity. A standard deviation increase in the Katz-Bonacich centrality increases the pupil school performance by more than 7 percent of one standard deviation.

Journal ArticleDOI
TL;DR: OCTOPUS, a new method for predicting transmembrane protein topology, is presented and benchmarked using a dataset of 124 sequences with known structures and is the first topology predictor to fully integrate modeling of reentrant/ Membrane-dipping regions and transmemBRane hairpins in the topological grammar.
Abstract: Motivation: As α-helical transmembrane proteins constitute roughly 25% of a typical genome and are vital parts of many essential biological processes, structural knowledge of these proteins is necessary for increasing our understanding of such processes. Because structural knowledge of transmembrane proteins is difficult to attain experimentally, improved methods for prediction of structural features of these proteins are important. Results: OCTOPUS, a new method for predicting transmembrane protein topology is presented and benchmarked using a dataset of 124 sequences with known structures. Using a novel combination of hidden Markov models and artificial neural networks, OCTOPUS predicts the correct topology for 94% of the sequences. In particular, OCTOPUS is the first topology predictor to fully integrate modeling of reentrant/membrane-dipping regions and transmembrane hairpins in the topological grammar. Availability: OCTOPUS is available as a web server at http://octopus.cbr.su.se. Contact: arne@bioinfo.se Supplementary information: Supplementary data are available at Bioinformatics online.

Journal ArticleDOI
TL;DR: A genomic approach to finding new protein-coding genes for systematics in nonmodel taxa, which can be PCR amplified from standard, slightly degraded genomic DNA extracts is described.
Abstract: Increasing the number of characters used in phylogenetic studies is the next crucial step towards generating robust and stable phylogenetic hypotheses - i.e., strongly supported and consistent across reconstruction method. Here we describe a genomic approach to finding new protein-coding genes for systematics in nonmodel taxa, which can be PCR amplified from standard, slightly degraded genomic DNA extracts. We test this approach on Lepidoptera, searching the draft genomic sequence of the silk moth Bombyx mori, for exons > 500 bp in length, removing annotated gene families, and compared remaining exons with butterfly EST databases to identify conserved regions for primer design. These primers were tested on a set of 65 taxa primarily in the butterfly family Nymphalidae. We were able to identify and amplify six previously unused gene regions (Arginine Kinase, GAPDH, IDH, MDH, RpS2, and RpS5) and two rarely used gene regions (CAD and DDC) that when added to the three traditional gene regions (COI, EF-1alpha and wingless) gave a data set of 8114 bp. Phylogenetic robustness and stability increased with increasing numbers of genes. Smaller taxanomic subsets were also robust when using the full gene data set. The full 11-gene data set was robust and stable across reconstruction methods, recovering the major lineages and strongly supporting relationships within them. Our methods and insights should be applicable to taxonomic groups having a single genomic reference species and several EST databases from taxa that diverged less than 100 million years ago.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the relationship between employability and both work-related engagement and general life satisfaction well-being, and found that employability is positively associated with both engagement and life satisfaction.
Abstract: The current study's aims are twofold: first, we investigate the relationship between employability and both work-related (engagement) and general (life satisfaction) well-being. Second, we study ho ...

Journal ArticleDOI
TL;DR: While stand structure in mangrove stands is dependent on age, site conditions and silvicultural management, published data indicates that stem densities are higher in restored mangroves than comparable natural stands; the converse is true for basal area.