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Showing papers by "Colorado State University published in 2010"


Proceedings ArticleDOI
13 Jun 2010
TL;DR: A new type of correlation filter is presented, a Minimum Output Sum of Squared Error (MOSSE) filter, which produces stable correlation filters when initialized using a single frame, which enables the tracker to pause and resume where it left off when the object reappears.
Abstract: Although not commonly used, correlation filters can track complex objects through rotations, occlusions and other distractions at over 20 times the rate of current state-of-the-art techniques. The oldest and simplest correlation filters use simple templates and generally fail when applied to tracking. More modern approaches such as ASEF and UMACE perform better, but their training needs are poorly suited to tracking. Visual tracking requires robust filters to be trained from a single frame and dynamically adapted as the appearance of the target object changes. This paper presents a new type of correlation filter, a Minimum Output Sum of Squared Error (MOSSE) filter, which produces stable correlation filters when initialized using a single frame. A tracker based upon MOSSE filters is robust to variations in lighting, scale, pose, and nonrigid deformations while operating at 669 frames per second. Occlusion is detected based upon the peak-to-sidelobe ratio, which enables the tracker to pause and resume where it left off when the object reappears.

2,948 citations


Journal ArticleDOI
TL;DR: Advanced analysis topics covered include the use of multipliers to allow analysis of indirect surveys, the density surface modelling analysis engine for spatial and habitat modelling, and information about accessing the analysis engines directly from other software.
Abstract: Summary 1. Distance sampling is a widely used technique for estimating the size or density of biological populations. Many distance sampling designs and most analyses use the software Distance. 2. We briefly review distance sampling and its assumptions, outline the history, structure and capabilities of Distance, and provide hints on its use. 3. Good survey design is a crucial prerequisite for obtaining reliable results. Distance has a survey design engine, with a built-in geographic information system, that allows properties of different proposed designs to be examined via simulation, and survey plans to be generated. 4. A first step in analysis of distance sampling data is modelling the probability of detection. Distance contains three increasingly sophisticated analysis engines for this: conventional distance sampling, which models detection probability as a function of distance from the transect and assumes all objects at zero distance are detected; multiple-covariate distance sampling, which allows covariates in addition to distance; and mark–recapture distance sampling, which relaxes the assumption of certain detection at zero distance. 5. All three engines allow estimation of density or abundance, stratified if required, with associated measures of precision calculated either analytically or via the bootstrap. 6. Advanced analysis topics covered include the use of multipliers to allow analysis of indirect surveys (such as dung or nest surveys), the density surface modelling analysis engine for spatial and habitat modelling, and information about accessing the analysis engines directly from other software. 7.Synthesis and applications. Distance sampling is a key method for producing abundance and density estimates in challenging field conditions. The theory underlying the methods continues to expand to cope with realistic estimation situations. In step with theoretical developments, state-of-the-art software that implements these methods is described that makes the methods accessible to practising ecologists.

1,878 citations


Journal ArticleDOI
TL;DR: In an effort to develop quantitative relationships between various kinds of flow alteration and ecological responses, this paper reviewed 165 papers published over the last four decades, with a focus on more recent papers.
Abstract: Summary 1. In an effort to develop quantitative relationships between various kinds of flow alteration and ecological responses, we reviewed 165 papers published over the last four decades, with a focus on more recent papers. Our aim was to determine if general relationships could be drawn from disparate case studies in the literature that might inform environmental flows science and management. 2. For all 165 papers we characterised flow alteration in terms of magnitude, frequency, duration, timing and rate of change as reported by the individual studies. Ecological responses were characterised according to taxonomic identity (macroinvertebrates, fish, riparian vegetation) and type of response (abundance, diversity, demographic parameters). A ‘qualitative’ or narrative summary of the reported results strongly corroborated previous, less comprehensive, reviews by documenting strong and variable ecological responses to all types of flow alteration. Of the 165 papers, 152 (92%) reported decreased values for recorded ecological metrics in response to a variety of types of flow alteration, whereas 21 papers (13%) reported increased values. 3. Fifty-five papers had information suitable for quantitative analysis of ecological response to flow alteration. Seventy per cent of these papers reported on alteration in flow magnitude, yielding a total of 65 data points suitable for analysis. The quantitative analysis provided some insight into the relative sensitivities of different ecological groups to alteration in flow magnitudes, but robust statistical relationships were not supported. Macroinvertebrates showed mixed responses to changes in flow magnitude, with abundance and diversity both increasing and decreasing in response to elevated flows and to reduced flows. Fish abundance, diversity and demographic rates consistently declined in response to both elevated and reduced flow magnitude. Riparian vegetation metrics both increased and decreased in response to reduced peak flows, with increases reflecting mostly enhanced non-woody vegetative cover or encroachment into the stream channel. 4. Our analyses do not support the use of the existing global literature to develop general, transferable quantitative relationships between flow alteration and ecological response; however, they do support the inference that flow alteration is associated with ecological change and that the risk of ecological change increases with increasing magnitude of flow alteration. 5. New sampling programs and analyses that target sites across well-defined gradients of flow alteration are needed to quantify ecological response and develop robust and general flow alteration–ecological response relationships. Similarly, the collection of pre- and post-alteration data for new water development programs would significantly add to our basic understanding of ecological responses to flow alteration.

1,761 citations


Journal ArticleDOI
TL;DR: The ecological limits of hydrologic alteration (ELOHA) as mentioned in this paper is a framework for assessing environmental flow needs for many streams and rivers simultaneously to foster development and implementation of environmental flow standards at the regional scale.
Abstract: SUMMARY 1. The flow regime is a primary determinant of the structure and function of aquatic and riparian ecosystems for streams and rivers. Hydrologic alteration has impaired riverine ecosystems on a global scale, and the pace and intensity of human development greatly exceeds the ability of scientists to assess the effects on a river-by-river basis. Current scientific understanding of hydrologic controls on riverine ecosystems and experience gained from individual river studies support development of environmental flow standards at the regional scale. 2. This paper presents a consensus view from a group of international scientists on a new framework for assessing environmental flow needs for many streams and rivers simultaneously to foster development and implementation of environmental flow standards at the regional scale. This framework, the ecological limits of hydrologic alteration (ELOHA), is a synthesis of a number of existing hydrologic techniques and environmental flow methods that are currently being used to various degrees and that can support comprehensive regional flow management. The flexible approach allows

1,408 citations


Journal ArticleDOI
TL;DR: In this article, the authors explore the mechanisms using a microbial-enzyme model to simulate the responses of soil carbon to warming by 5'∘C. They find that declines in microbial biomass and degradative enzymes can explain the observed attenuation of soil-carbon emissions in response to warming.
Abstract: The loss of carbon dioxide from soils increases initially under climate warming, but tends to decline to control levels within a few years. Simulations of the soil-carbon response to warming with a microbial-enzyme model show that a decline in both microbial biomass and the production of degrading enzymes can explain this attenuation response. Most ecosystem models predict that climate warming will stimulate microbial decomposition of soil carbon, producing a positive feedback to rising global temperatures1,2. Although field experiments document an initial increase in the loss of CO2 from soils in response to warming, in line with these predictions, the carbon dioxide loss from soils tends to decline to control levels within a few years3,4,5. This attenuation response could result from changes in microbial physiological properties with increasing temperature, such as a decline in the fraction of assimilated carbon that is allocated to growth, termed carbon-use efficiency6. Here we explore these mechanisms using a microbial-enzyme model to simulate the responses of soil carbon to warming by 5 ∘C. We find that declines in microbial biomass and degradative enzymes can explain the observed attenuation of soil-carbon emissions in response to warming. Specifically, reduced carbon-use efficiency limits the biomass of microbial decomposers and mitigates the loss of soil carbon. However, microbial adaptation or a change in microbial communities could lead to an upward adjustment of the efficiency of carbon use, counteracting the decline in microbial biomass and accelerating soil-carbon loss. We conclude that the soil-carbon response to climate warming depends on the efficiency of soil microbes in using carbon.

1,142 citations


Journal ArticleDOI
TL;DR: Recent advances in the understanding of biogeochemical redox processes are highlighted and their impact on contaminant fate and transport, including future research needs are highlighted.
Abstract: Life and element cycling on Earth is directly related to electron transfer (or redox) reactions. An understanding of biogeochemical redox processes is crucial for predicting and protecting environmental health and can provide new opportunities for engineered remediation strategies. Energy can be released and stored by means of redox reactions via the oxidation of labile organic carbon or inorganic compounds (electron donors) by microorganisms coupled to the reduction of electron acceptors including humic substances, iron-bearing minerals, transition metals, metalloids, and actinides. Environmental redox processes play key roles in the formation and dissolution of mineral phases. Redox cycling of naturally occurring trace elements and their host minerals often controls the release or sequestration of inorganic contaminants. Redox processes control the chemical speciation, bioavailability, toxicity, and mobility of many major and trace elements including Fe, Mn, C, P, N, S, Cr, Cu, Co, As, Sb, Se, Hg, Tc, a...

1,029 citations


Journal ArticleDOI
TL;DR: It is suggested that changes in species diversity within and across trophic levels can significantly alter decomposition and this happens through various mechanisms that are broadly similar in forest floors and streams.
Abstract: Over 100 gigatons of terrestrial plant biomass are produced globally each year. Ninety percent of this biomass escapes herbivory and enters the dead organic matter pool, thus supporting complex detritus-based food webs that determine the critical balance between carbon mineralization and sequestration. How will changes in biodiversity affect this vital component of ecosystem functioning? Based on our analysis of concepts and experiments of leaf decomposition in forest floors and streams, we suggest that changes in species diversity within and across trophic levels can significantly alter decomposition. This happens through various mechanisms that are broadly similar in forest floors and streams. Differences in diversity effects between these systems relate to divergent habitat conditions and evolutionary trajectories of aquatic and terrestrial decomposers.

1,027 citations


Journal ArticleDOI
TL;DR: It is shown that the concentrations of ice nuclei active in mixed-phase cloud conditions can be related to temperature and the number concentrations of particles larger than 0.5 μm in diameter, which reduces unexplained variability in iceuclei concentrations at a given temperature from ∼103 to less than a factor of 10.
Abstract: Knowledge of cloud and precipitation formation processes remains incomplete, yet global precipitation is predominantly produced by clouds containing the ice phase. Ice first forms in clouds warmer than -36 °C on particles termed ice nuclei. We combine observations from field studies over a 14-year period, from a variety of locations around the globe, to show that the concentrations of ice nuclei active in mixed-phase cloud conditions can be related to temperature and the number concentrations of particles larger than 0.5 μm in diameter. This new relationship reduces unexplained variability in ice nuclei concentrations at a given temperature from ∼103 to less than a factor of 10, with the remaining variability apparently due to variations in aerosol chemical composition or other factors. When implemented in a global climate model, the new parameterization strongly alters cloud liquid and ice water distributions compared to the simple, temperature-only parameterizations currently widely used. The revised treatment indicates a global net cloud radiative forcing increase of ∼1 W m-2 for each order of magnitude increase in ice nuclei concentrations, demonstrating the strong sensitivity of climate simulations to assumptions regarding the initiation of cloud glaciation.

1,010 citations


Journal ArticleDOI
30 Apr 2010-Science
TL;DR: A synthesis of grass evolutionary biology with grassland ecosystem science will further knowledge of the evolution of traits that promote dominance in grassland systems and will provide a new context in which to evaluate the relative importance of C4 photosynthesis in transforming ecosystems across large regions of Earth.
Abstract: The evolution of grasses using C4 photosynthesis and their sudden rise to ecological dominance 3 to 8 million years ago is among the most dramatic examples of biome assembly in the geological record. A growing body of work suggests that the patterns and drivers of C4 grassland expansion were considerably more complex than originally assumed. Previous research has benefited substantially from dialog between geologists and ecologists, but current research must now integrate fully with phylogenetics. A synthesis of grass evolutionary biology with grassland ecosystem science will further our knowledge of the evolution of traits that promote dominance in grassland systems and will provide a new context in which to evaluate the relative importance of C4 photosynthesis in transforming ecosystems across large regions of Earth.

878 citations


Journal ArticleDOI
TL;DR: A broad range of findings that indicate the potential severity of this threat to diverse taxa, and recent studies that document substantial changes in foraging and anti-predator behavior, reproductive success, density and community structure in response to noise are reviewed.
Abstract: Growth in transportation networks, resource extraction, motorized recreation and urban development is responsible for chronic noise exposure in most terrestrial areas, including remote wilderness sites. Increased noise levels reduce the distance and area over which acoustic signals can be perceived by animals. Here, we review a broad range of findings that indicate the potential severity of this threat to diverse taxa, and recent studies that document substantial changes in foraging and anti-predator behavior, reproductive success, density and community structure in response to noise. Effective management of protected areas must include noise assessment, and research is needed to further quantify the ecological consequences of chronic noise exposure in terrestrial environments.

805 citations


Book ChapterDOI
TL;DR: This work provides a basic understanding of the theory behind SVMs and focuses on their use in practice, describing the effect of the SVM parameters on the resulting classifier, how to select good values for those parameters, data normalization, factors that affect training time, and software for training SVMs.
Abstract: The Support Vector Machine (SVM) is a widely used classifier in bioinformatics. Obtaining the best results with SVMs requires an understanding of their workings and the various ways a user can influence their accuracy. We provide the user with a basic understanding of the theory behind SVMs and focus on their use in practice. We describe the effect of the SVM parameters on the resulting classifier, how to select good values for those parameters, data normalization, factors that affect training time, and software for training SVMs.

Journal ArticleDOI
01 Oct 2010-Science
TL;DR: A photoelectrochemical system composed of PbS nanocrystals chemically bound to TiO2 single crystals is used to demonstrate the collection of photocurrents with quantum yields greater than one electron per photon, which has implications for increasing the efficiency of photovoltaic devices by avoiding losses resulting from the thermalization of photogenerated carriers.
Abstract: Multiple exciton generation, the creation of two electron-hole pairs from one high-energy photon, is well established in bulk semiconductors, but assessments of the efficiency of this effect remain controversial in quantum-confined systems like semiconductor nanocrystals. We used a photoelectrochemical system composed of PbS nanocrystals chemically bound to TiO 2 single crystals to demonstrate the collection of photocurrents with quantum yields greater than one electron per photon. The strong electronic coupling and favorable energy level alignment between PbS nanocrystals and bulk TiO 2 facilitate extraction of multiple excitons more quickly than they recombine, as well as collection of hot electrons from higher quantum dot excited states. Our results have implications for increasing the efficiency of photovoltaic devices by avoiding losses resulting from the thermalization of photogenerated carriers.

Journal ArticleDOI
TL;DR: It is concluded that tests of working memory capacity and executive function share a common underlying executive attention component that is strongly predictive of higher level cognition.
Abstract: Attentional control has been conceptualized as executive functioning by neuropsychologists and as working memory capacity by experimental psychologists. We examined the relationship between these constructs using a factor analytic approach in an adult life span sample. Several tests of working memory capacity and executive function were administered to more than 200 subjects between 18 and 90 years of age, along with tests of processing speed and episodic memory. The correlation between working memory capacity and executive functioning constructs was very strong (r = .97), but correlations between these constructs and processing speed were considerably weaker (rs approximately .79). Controlling for working memory capacity and executive function eliminated age effects on episodic memory, and working memory capacity and executive function accounted for variance in episodic memory beyond that accounted for by processing speed. We conclude that tests of working memory capacity and executive function share a common underlying executive attention component that is strongly predictive of higher level cognition.

Journal ArticleDOI
TL;DR: It is argued that this ability to respond to physiological changes by modulating those same changes makes the ADF/cofilin protein family a homeostatic regulator or 'functional node' in cell biology.

Journal ArticleDOI
TL;DR: In this paper, the authors used CloudSat data to assess the realism of global model precipitation and found that the observed and modeled precipitation are significantly different from the character of liquid precipitation produced by global weather and climate models.
Abstract: [1] New, definitive measures of precipitation frequency provided by CloudSat are used to assess the realism of global model precipitation. The character of liquid precipitation (defined as a combination of accumulation, frequency, and intensity) over the global oceans is significantly different from the character of liquid precipitation produced by global weather and climate models. Five different models are used in this comparison representing state-of-the-art weather prediction models, state-of-the-art climate models, and the emerging high-resolution global cloud “resolving” models. The differences between observed and modeled precipitation are larger than can be explained by observational retrieval errors or by the inherent sampling differences between observations and models. We show that the time integrated accumulations of precipitation produced by models closely match observations when globally composited. However, these models produce precipitation approximately twice as often as that observed and make rainfall far too lightly. This finding reinforces similar findings from other studies based on surface accumulated rainfall measurements. The implications of this dreary state of model depiction of the real world are discussed.

Journal ArticleDOI
TL;DR: This work investigated recently discovered glyphosate-resistant Amaranthus palmeri populations from Georgia, in comparison with normally sensitive populations, and revealed that EPSPS genes were present on every chromosome and, therefore, gene amplification was likely not caused by unequal chromosome crossing over.
Abstract: The herbicide glyphosate became widely used in the United States and other parts of the world after the commercialization of glyphosate-resistant crops. These crops have constitutive overexpression of a glyphosate-insensitive form of the herbicide target site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Increased use of glyphosate over multiple years imposes selective genetic pressure on weed populations. We investigated recently discovered glyphosate-resistant Amaranthus palmeri populations from Georgia, in comparison with normally sensitive populations. EPSPS enzyme activity from resistant and susceptible plants was equally inhibited by glyphosate, which led us to use quantitative PCR to measure relative copy numbers of the EPSPS gene. Genomes of resistant plants contained from 5-fold to more than 160-fold more copies of the EPSPS gene than did genomes of susceptible plants. Quantitative RT-PCR on cDNA revealed that EPSPS expression was positively correlated with genomic EPSPS relative copy number. Immunoblot analyses showed that increased EPSPS protein level also correlated with EPSPS genomic copy number. EPSPS gene amplification was heritable, correlated with resistance in pseudo-F2 populations, and is proposed to be the molecular basis of glyphosate resistance. FISH revealed that EPSPS genes were present on every chromosome and, therefore, gene amplification was likely not caused by unequal chromosome crossing over. This occurrence of gene amplification as an herbicide resistance mechanism in a naturally occurring weed population is particularly significant because it could threaten the sustainable use of glyphosate-resistant crop technology.

Book
15 Mar 2010
TL;DR: This chapter discusses the origins and uses of complex signals, and the importance of majorization in the development of complex random vectors and processes.
Abstract: Complex-valued random signals are embedded in the very fabric of science and engineering, yet the usual assumptions made about their statistical behavior are often a poor representation of the underlying physics. This book deals with improper and noncircular complex signals, which do not conform to classical assumptions, and it demonstrates how correct treatment of these signals can have significant payoffs. The book begins with detailed coverage of the fundamental theory and presents a variety of tools and algorithms for dealing with improper and noncircular signals. It provides a comprehensive account of the main applications, covering detection, estimation, and signal analysis of stationary, nonstationary, and cyclostationary processes. Providing a systematic development from the origin of complex signals to their probabilistic description makes the theory accessible to newcomers. This book is ideal for graduate students and researchers working with complex data in a range of research areas from communications to oceanography.

Journal ArticleDOI
TL;DR: The measurement of the depth of maximum, X{max}, of the longitudinal development of air showers induced by cosmic rays is described and the interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.
Abstract: We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.

Journal ArticleDOI
TL;DR: Highlights gaps in knowledge and methodology are highlighted, providing guidelines to authors and reviewers of landscape genetics studies, and suggesting promising future directions of inquiry are suggested.
Abstract: Landscape genetics has seen rapid growth in number of publications since the term was coined in 2003. An extensive literature search from 1998 to 2008 using keywords associated with landscape genetics yielded 655 articles encompassing a vast array of study organisms, study designs and methodology. These publications were screened to identify 174 studies that explicitly incorporated at least one landscape variable with genetic data. We systematically reviewed this set of papers to assess taxonomic and temporal trends in: (i) geographic regions studied; (ii) types of questions addressed; (iii) molecular markers used; (iv) statistical analyses used; and (v) types and nature of spatial data used. Overall, studies have occurred in geographic regions proximal to developed countries and more commonly in terrestrial vs. aquatic habitats. Questions most often focused on effects of barriers and/or landscape variables on gene flow. The most commonly used molecular markers were microsatellites and amplified fragment length polymorphism (AFLPs), with AFLPs used more frequently in plants than animals. Analysis methods were dominated by Mantel and assignment tests. We also assessed differences among journals to evaluate the uniformity of reporting and publication standards. Few studies presented an explicit study design or explicit descriptions of spatial extent. While some landscape variables such as topographic relief affected most species studied, effects were not universal, and some species appeared unaffected by the landscape. Effects of habitat fragmentation were mixed, with some species altering movement paths and others unaffected. Taken together, although some generalities emerged regarding effects of specific landscape variables, results varied, thereby reinforcing the need for species-specific work. We conclude by: highlighting gaps in knowledge and methodology, providing guidelines to authors and reviewers of landscape genetics studies, and suggesting promising future directions of inquiry.

Journal ArticleDOI
17 Sep 2010-Science
TL;DR: It is shown that the fine submicrometer particles accounting for most cloud condensation nuclei are predominantly composed of secondary organic material formed by oxidation of gaseous biogenic precursors, which is relevant as ice nuclei.
Abstract: The Amazon is one of the few continental regions where atmospheric aerosol particles and their effects on climate are not dominated by anthropogenic sources. During the wet season, the ambient conditions approach those of the pristine pre-industrial era. We show that the fine submicrometer particles accounting for most cloud condensation nuclei are predominantly composed of secondary organic material formed by oxidation of gaseous biogenic precursors. Supermicrometer particles, which are relevant as ice nuclei, consist mostly of primary biological material directly released from rainforest biota. The Amazon Basin appears to be a biogeochemical reactor, in which the biosphere and atmospheric photochemistry produce nuclei for clouds and precipitation sustaining the hydrological cycle. The prevailing regime of aerosol-cloud interactions in this natural environment is distinctly different from polluted regions.

Journal ArticleDOI
TL;DR: The oxidative cycloaddition of benzamides and alkynes has been developed and unsymmetrical alkynes proceed with excellent regioselectivity, and heteroaryl carboxamides are tolerated leading to intriguing scaffolds for medicinal chemistry.
Abstract: The oxidative cycloaddition of benzamides and alkynes has been developed. The reaction utilizes Rh(III) catalysts in the presence of Cu(II) oxidants, and is proposed to proceed by N−H metalation of the amide followed by ortho C−H activation. The resultant rhodacycle undergoes alkyne insertion to form isoquinolones in good yield. The reaction is tolerant of extensive substitution on the amide, alkyne, and arene, including halides, silyl ethers, and unprotected aldehydes as substituents. Unsymmetrical alkynes proceed with excellent regioselectivity, and heteroaryl carboxamides are tolerated leading to intriguing scaffolds for medicinal chemistry. A series of competition experiments shed further light on the mechanism of the transformation and reasons for selectivity.

Journal ArticleDOI
Bernard Aubert1, Y. Karyotakis1, J. P. Lees1, V. Poireau1  +488 moreInstitutions (78)
TL;DR: In this article, the authors performed searches for lepton-flavor-violating decays of a tau lepton to a lighter mass lepton and a photon with the entire data set of (963 +/- 7) x 10(6) tau decays collected by the BABAR detector near the Y(4S), Y(3S) and Y(2S) resonances.
Abstract: Searches for lepton-flavor-violating decays of a tau lepton to a lighter mass lepton and a photon have been performed with the entire data set of (963 +/- 7) x 10(6) tau decays collected by the BABAR detector near the Y(4S), Y(3S) and Y(2S) resonances. The searches yield no evidence of signals and we set upper limits on the branching fractions of B(tau(+/-) -> e(+/-)gamma) mu(+/-)gamma) < 4.4 X 10(-8) at 90% confidence level.

Journal ArticleDOI
TL;DR: In this paper, the authors define entrepreneurial exit and demonstrate how this conceptualization provides concepts that are unique from those addressed by researchers in other domains; thus outlining a space for it within the literature.

Journal ArticleDOI
TL;DR: In this article, the authors used image segmentation of 500 m MODIS data to produce a global map of 4.4 million forest patches, where a Geoscience Laser Altimeter System (GLAS) transect intersects a patch, its height is calculated from the GLAS observations directly.
Abstract: [1] The value of lidar derives from its ability to map ecosystem vertical structure which can be used to estimate aboveground carbon storage. Spaceborne lidar sensors collect data along transects and gain value for the global change science community when combined with data sources that have complete horizontal coverage. Data sources and methods for this type of analysis require evaluation. In this work we use image segmentation of 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) data to produce a global map of 4.4 million forest patches. Where a Geoscience Laser Altimeter System (GLAS) transect intersects a patch, its height is calculated from the GLAS observations directly. Regression analysis is then used to estimate the heights of those patches without GLAS observations. Regression goodness-of-fit statistics indicate moderately strong relationships for predicting the 90th percentile patch height, with a mean RMSE of 5.9 m and mean correlation (R2) of 0.67.

Journal ArticleDOI
TL;DR: In this article, a theoretical framework for predicting changes in community composition and ecosystem function in a rapidly changing world is proposed, consisting of three elements: an underlying trait distribution, a performance filter defining the fitness of traits in different environments, and a dynamic projection of the performance filter along some environmental gradient.
Abstract: Predicting changes in community composition and ecosystem function in a rapidly changing world is a major research challenge in ecology. Traits-based approaches have elicited much recent interest, yet individual studies are not advancing a more general, predictive ecology. Significant progress will be facilitated by adopting a coherent theoretical framework comprised of three elements: an underlying trait distribution, a performance filter defining the fitness of traits in different environments, and a dynamic projection of the performance filter along some environmental gradient. This framework allows changes in the trait distribution and associated modifications to community composition or ecosystem function to be predicted across time or space. The structure and dynamics of the performance filter specify two key criteria by which we judge appropriate quantitative methods for testing traits-based hypotheses. Bayesian multilevel models, dynamical systems models and hybrid approaches meet both these criteria and have the potential to meaningfully advance traits-based ecology.

Journal ArticleDOI
TL;DR: Song et al. as discussed by the authors proposed a more general version of the independent learning with ranking the maximum marginal likelihood estimates in generalized linear models and showed that the proposed methods also possess the sure screening property with vanishing false selection rate, which justifies the applicability of such a simple method in a wide spectrum.
Abstract: Ultrahigh dimensional variable selection plays an increasingly important role in contemporary scientific discoveries and statistical research. Among others, Fan and Lv (2008) propose an independent screening framework by ranking the marginal correlations. They showed that the correlation ranking procedure possesses a sure independence screening property within the context of the linear model with Gaussian covariates and responses. In this paper, we propose a more general version of the independent learning with ranking the maximum marginal likelihood estimates or the maximum marginal likelihood itself in generalized linear models. We show that the proposed methods, with Fan and Lv (2008) as a very special case, also possess the sure screening property with vanishing false selection rate. The conditions under which that the independence learning possesses a sure screening is surprisingly simple. This justifies the applicability of such a simple method in a wide spectrum. We quantify explicitly the extent to which the dimensionality can be reduced by independence screening, which depends on the interactions of the covariance matrix of covariates and true parameters. Simulation studies are used to illustrate the utility of the proposed approaches. In addition, we � Supported in part by Grant NSF grants DMS-0714554 and DMS-0704337. The bulk of the work was conducted when Rui Song was a postdoctoral research fellow at Princeton University. The authors would like to thank the associate editor and two referees for their constructive comments that improve the presentation and the results of the paper. AMS 2000 subject classifications: Primary 68Q32, 62J12; secondary 62E99, 60F10

Journal ArticleDOI
J. Abraham1, P. Abreu2, Marco Aglietta3, Eun-Joo Ahn4  +489 moreInstitutions (65)
TL;DR: In this article, the authors reported a measurement of the flux of cosmic rays with unprecedented precision and statistics using the Pierre Auger Observatory based on fluorescence observations in coincidence with at least one surface detector.

Journal ArticleDOI
TL;DR: The authors dub the molecular events associated with death-induced proliferation the “phoenix rising” pathway, which involves the caspase-mediated activation of phospholipase A2 and the subsequent production and release of the lipid signal prostaglandin E2, a stimulator of cell proliferation.
Abstract: The ability to regenerate damaged tissues is a common characteristic of multicellular organisms. We report a role for apoptotic cell death in promoting wound healing and tissue regeneration in mice. Apoptotic cells released growth signals that stimulated the proliferation of progenitor or stem cells. Key players in this process were caspases 3 and 7, proteases activated during the execution phase of apoptosis that contribute to cell death. Mice lacking either of these caspases were deficient in skin wound healing and in liver regeneration. Prostaglandin E 2 , a promoter of stem or progenitor cell proliferation and tissue regeneration, acted downstream of the caspases. We propose to call the pathway by which executioner caspases in apoptotic cells promote wound healing and tissue regeneration in multicellular organisms the “phoenix rising” pathway.

Journal ArticleDOI
Peter Arensburger1, Karyn Megy, Robert M. Waterhouse2, Robert M. Waterhouse3, Jenica L. Abrudan4, Paolo Amedeo5, Beatriz García Antelo6, Lyric C. Bartholomay7, Shelby L. Bidwell, Elisabet Caler5, Francisco Camara, Corey L. Campbell8, Kathryn S. Campbell9, Claudio Casola10, Marta T Castro11, Ishwar Chandramouliswaran5, Sinéad B. Chapman12, Scott Christley4, Javier Costas, Eric Eisenstadt5, Cédric Feschotte13, Claire M. Fraser-Liggett14, Roderic Guigó, Brian J. Haas12, Martin Hammond, Bill S. Hansson15, Janet Hemingway16, Sharon R. Hill17, Clint Howarth12, Rickard Ignell17, Ryan C. Kennedy4, Chinnappa D. Kodira18, Neil F. Lobo4, Chunhong Mao19, George F. Mayhew20, Kristin Michel21, Akio Mori4, Nannan Liu22, Horacio Naveira23, Vishvanath Nene14, Vishvanath Nene24, Nam P. Nguyen13, Matthew D. Pearson12, Ellen J. Pritham13, Daniela Puiu25, Yumin Qi19, Hilary Ranson16, José M. C. Ribeiro26, Hugh M Roberston27, David W. Severson4, Martin Shumway26, Mario Stanke28, Robert L. Strausberg5, Cheng Sun13, Granger G. Sutton5, Zhijian Jake Tu19, Jose M. C. Tubio6, Maria F. Unger4, Dana L. Vanlandingham29, Albert J. Vilella, Owen White14, Jared White12, Charles S. Wondji16, Jennifer R. Wortman14, Evgeny M. Zdobnov29, Evgeny M. Zdobnov2, Evgeny M. Zdobnov3, Bruce W. Birren12, Bruce M. Christensen20, Frank H. Collins4, Anthony J. Cornel30, George Dimopoulos31, Linda Hannick5, Stephen Higgs29, Gregory C. Lanzaro32, Daniel Lawson, Norman H. Lee33, Marc A. T. Muskavitch12, Marc A. T. Muskavitch34, Marc A. T. Muskavitch9, Alexander S. Raikhel1, Peter W. Atkinson1 
01 Oct 2010-Science
TL;DR: The genomic sequence of C. quinquefasciatus is described, which reveals distinctions related to vector capacities and habitat preferences, and confirmed that inoculation with unfamiliar bacteria prompted strong immune responses in Culex.
Abstract: Culex quinquefasciatus (the southern house mosquito) is an important mosquito vector of viruses such as West Nile virus and St. Louis encephalitis virus, as well as of nematodes that cause lymphatic filariasis. C. quinquefasciatus is one species within the Culex pipiens species complex and can be found throughout tropical and temperate climates of the world. The ability of C. quinquefasciatus to take blood meals from birds, livestock, and humans contributes to its ability to vector pathogens between species. Here, we describe the genomic sequence of C. quinquefasciatus: Its repertoire of 18,883 protein-coding genes is 22% larger than that of Aedes aegypti and 52% larger than that of Anopheles gambiae with multiple gene-family expansions, including olfactory and gustatory receptors, salivary gland genes, and genes associated with xenobiotic detoxification.

Journal ArticleDOI
TL;DR: In this article, the authors propose a metaphor of the prisoner's dilemma, which they call the green prison, in which entrepreneurs are compelled to environmentally degrading behavior due to the divergence between individual rewards and collective goals for sustainable development.