cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.1569850.v2
title: Mesophase behaviour of laterally di-fluoro-substituted four-ring compounds

description: Four new groups of the di-fluoro-substituted 4-(2′-(or 3′)-fluoro phenylazo)-2-(or 3-) fluoro phenyl-4″-alkoxyphenylazo benzoates (<b>I</b><i>n</i>–<b>IV</b><i>n</i>) were prepared and investigated for their mesophase behaviour. An alkoxy group of variable chain length (<i>n</i> = 6, 10 and 14 carbons) is attached to the terminal phenylazo benzoate moiety, and two lateral fluoro substituents are attached individually with different orientations to the other two adjacent rings. The molecular structures of the prepared compounds were confirmed by Fourier transform infrared spectroscopy and <sup>1</sup>H NMR spectroscopy. The study aims to investigate the steric effect of the spatial orientation and relative positions of the two lateral fluorine atoms on the mesomorphic properties in their pure states. The mesophase behaviour was investigated via differential scanning calorimetry and mesophases were identified by polarised light microscopy. The investigation shows that these compounds exhibit high enantiotropic mesophases (SmC and N) and broad mesophase temperature range. The type and stability of the mesophase depends on the length of the terminal alkoxy chain and the position the two fluoro substituents. A comparison between these investigated compounds with their corresponding three-ring analogues was discussed.
DOI: 10.6084/m9.figshare.1569848
title: Comparative modeling of exposure to airborne nanoparticles released by consumer spray products

description: Consumer exposure to sprays containing nano-objects is a continuing concern as a potential health hazard. One potential hazard has been formulated in the overload hypothesis. It describes a volume fraction of the macrophages that is occupied by deposited nanoparticles that leads to reduced macrophage mobility. Subsequent chronic inflammation may then lead to severe health consequences including cancer. To calculate lung deposition of spherical particles, the Multiple-Path Particle Dosimetry (MPPD) model (ARA, Albuquerque, NM) provides different kinds of lung models and age settings. Using the MPPD v 2.11 software, we modeled several consumer-related exposure scenarios. Different body orientations and age groups were investigated. Moreover, a number of materials representing different densities were used, and the exposure calculated using MPPD is compared to the hazard derived from the overload hypothesis. Conditions leading to macrophage overload were found for exposures to high particle doses for prolonged times and repeated exposure. Such conditions are unlikely in the context of regular consumer exposure. The overload hypothesis assumes the particles to be inert and biopersistent, a condition that currently lacks a clear regulatory definition and is valid only for a few selected materials. Furthermore, because of material-specific effects and the possibility of surface adsorption of hazardous chemicals, nano-objects in propellant sprays remain of concern for consumer health.
DOI: 10.6084/m9.figshare.1569850.v4
title: Mesophase behaviour of laterally di-fluoro-substituted four-ring compounds

description: Four new groups of the di-fluoro-substituted 4-(2′-(or 3′)-fluoro phenylazo)-2-(or 3-) fluoro phenyl-4″-alkoxyphenylazo benzoates (<b>I</b><i>n</i>–<b>IV</b><i>n</i>) were prepared and investigated for their mesophase behaviour. An alkoxy group of variable chain length (<i>n</i> = 6, 10 and 14 carbons) is attached to the terminal phenylazo benzoate moiety, and two lateral fluoro substituents are attached individually with different orientations to the other two adjacent rings. The molecular structures of the prepared compounds were confirmed by Fourier transform infrared spectroscopy and <sup>1</sup>H NMR spectroscopy. The study aims to investigate the steric effect of the spatial orientation and relative positions of the two lateral fluorine atoms on the mesomorphic properties in their pure states. The mesophase behaviour was investigated via differential scanning calorimetry and mesophases were identified by polarised light microscopy. The investigation shows that these compounds exhibit high enantiotropic mesophases (SmC and N) and broad mesophase temperature range. The type and stability of the mesophase depends on the length of the terminal alkoxy chain and the position the two fluoro substituents. A comparison between these investigated compounds with their corresponding three-ring analogues was discussed.
DOI: 10.6084/m9.figshare.1569844
title: Phylogenetic relationships of tropical eastern Pacific snappers (Lutjanidae) inferred from mitochondrial DNA sequences

description: A total of 2,206 base pairs of coding sequences of mitochondrial DNA from nine of 10 lutjanine (Lutjanidae) species endemic to the eastern Pacific Ocean were used in a phylogenetic analysis to infer species relationships among lutjanines on either side of the Isthmus of Panama. Monotypic <i>Hoplopagrus</i> (<i>guentherii</i>) appears to be at the base of all lutjanines assayed to date and represents the first of five, eastward dispersal events of lutjanines from the Indo-Pacific to the Americas. Diversification of lutjanines in the Americas appears to have occurred primarily in the western Atlantic Ocean (Caribbean Sea) and been aided by an early Miocene eastward-flowing current and by more optimal lutjanine habitat in the warmer Caribbean waters. Five geminate species pairs in five, strongly supported clades were identified. In three, the trans-isthmian geminate species in the eastern Pacific belonged to clades in which basal and other members of the clade are endemic to the western Atlantic, suggesting that the ancestor to each species geminate pair dispersed westward into the eastern Pacific prior to closure of connections between the two oceans; the opposite occurred in one of the clades. The fifth clade contained only two species, one on either side of the Isthmus. Diversification in life-history and other traits in each geminate species pair appears to have been slight. Five lutjanine species possessing horizontal blue stripes (the blue-lined complex) and distributed from the western Indian Ocean to the eastern Pacific formed a strongly supported monophyletic clade. The lone blue-lined species in the eastern Pacific (<i>Lutjanus viridis</i>) could be conspecific with its highly dispersive sister species (<i>Lutjanus kasmira</i>) from the Indo-Pacific. The chronology of lutjanine diversification and closure of seawater exchange between the two oceans is briefly discussed.
DOI: 10.6084/m9.figshare.1569843
title: The evolution of thermal performance can constrain dispersal during range shifting

description: Organisms can cope with changing temperature under climate change by either adapting to the temperature at which they perform best and/or by dispersing to more benign locations. The evolution of a new thermal niche during range shifting is, however, expected to be strongly constrained by genetic load because spatial sorting is known to induce fast evolution of dispersal. To broaden our understanding of this interaction, we studied the joint evolution of dispersal and thermal performance curves (TPCs) of a population during range shifting by applying an individual-based spatially explicit model. Always, TPCs adapted to the local thermal conditions. Remarkably, this adaptation coincided with an evolution of dispersal at the shifting range front being equally high or lower than at the trailing edge. This optimal strategy reduces genetic load and highlights that evolutionary dynamics during range shifting change when crucial traits such as dispersal and thermal performance jointly evolve.
DOI: 10.6084/m9.figshare.1569850.v3
title: Mesophase behaviour of laterally di-fluoro-substituted four-ring compounds

description: Four new groups of the di-fluoro-substituted 4-(2′-(or 3′)-fluoro phenylazo)-2-(or 3-) fluoro phenyl-4″-alkoxyphenylazo benzoates (<b>I</b><i>n</i>–<b>IV</b><i>n</i>) were prepared and investigated for their mesophase behaviour. An alkoxy group of variable chain length (<i>n</i> = 6, 10 and 14 carbons) is attached to the terminal phenylazo benzoate moiety, and two lateral fluoro substituents are attached individually with different orientations to the other two adjacent rings. The molecular structures of the prepared compounds were confirmed by Fourier transform infrared spectroscopy and <sup>1</sup>H NMR spectroscopy. The study aims to investigate the steric effect of the spatial orientation and relative positions of the two lateral fluorine atoms on the mesomorphic properties in their pure states. The mesophase behaviour was investigated via differential scanning calorimetry and mesophases were identified by polarised light microscopy. The investigation shows that these compounds exhibit high enantiotropic mesophases (SmC and N) and broad mesophase temperature range. The type and stability of the mesophase depends on the length of the terminal alkoxy chain and the position the two fluoro substituents. A comparison between these investigated compounds with their corresponding three-ring analogues was discussed.
DOI: 10.6084/m9.figshare.1569844.v2
title: Phylogenetic relationships of tropical eastern Pacific snappers (Lutjanidae) inferred from mitochondrial DNA sequences

description: A total of 2,206 base pairs of coding sequences of mitochondrial DNA from nine of 10 lutjanine (Lutjanidae) species endemic to the eastern Pacific Ocean were used in a phylogenetic analysis to infer species relationships among lutjanines on either side of the Isthmus of Panama. Monotypic <i>Hoplopagrus</i> (<i>guentherii</i>) appears to be at the base of all lutjanines assayed to date and represents the first of five, eastward dispersal events of lutjanines from the Indo-Pacific to the Americas. Diversification of lutjanines in the Americas appears to have occurred primarily in the western Atlantic Ocean (Caribbean Sea) and been aided by an early Miocene eastward-flowing current and by more optimal lutjanine habitat in the warmer Caribbean waters. Five geminate species pairs in five, strongly supported clades were identified. In three, the trans-isthmian geminate species in the eastern Pacific belonged to clades in which basal and other members of the clade are endemic to the western Atlantic, suggesting that the ancestor to each species geminate pair dispersed westward into the eastern Pacific prior to closure of connections between the two oceans; the opposite occurred in one of the clades. The fifth clade contained only two species, one on either side of the Isthmus. Diversification in life-history and other traits in each geminate species pair appears to have been slight. Five lutjanine species possessing horizontal blue stripes (the blue-lined complex) and distributed from the western Indian Ocean to the eastern Pacific formed a strongly supported monophyletic clade. The lone blue-lined species in the eastern Pacific (<i>Lutjanus viridis</i>) could be conspecific with its highly dispersive sister species (<i>Lutjanus kasmira</i>) from the Indo-Pacific. The chronology of lutjanine diversification and closure of seawater exchange between the two oceans is briefly discussed.
DOI: 10.6084/m9.figshare.1569838
title: Diffusion Indexes With Sparse Loadings

description: The use of large-dimensional factor models in forecasting has received much attention in the literature with the consensus being that improvements on forecasts can be achieved when comparing with standard models. However, recent contributions in the literature have demonstrated that care needs to be taken when choosing which variables to include in the model. A number of different approaches to determining these variables have been put forward. These are, however, often based on ad hoc procedures or abandon the underlying theoretical factor model. In this article, we will take a different approach to the problem by using the least absolute shrinkage and selection operator (LASSO) as a variable selection method to choose between the possible variables and thus obtain sparse loadings from which factors or diffusion indexes can be formed. This allows us to build a more parsimonious factor model that is better suited for forecasting compared to the traditional principal components (PC) approach. We provide an asymptotic analysis of the estimator and illustrate its merits empirically in a forecasting experiment based on U.S. macroeconomic data. Overall we find that compared to PC we obtain improvements in forecasting accuracy and thus find it to be an important alternative to PC. Supplementary materials for this article are available online.
DOI: 10.6084/m9.figshare.1569844.v1
title: Phylogenetic relationships of tropical eastern Pacific snappers (Lutjanidae) inferred from mitochondrial DNA sequences

description: A total of 2,206 base pairs of coding sequences of mitochondrial DNA from nine of 10 lutjanine (Lutjanidae) species endemic to the eastern Pacific Ocean were used in a phylogenetic analysis to infer species relationships among lutjanines on either side of the Isthmus of Panama. Monotypic <i>Hoplopagrus</i> (<i>guentherii</i>) appears to be at the base of all lutjanines assayed to date and represents the first of five, eastward dispersal events of lutjanines from the Indo-Pacific to the Americas. Diversification of lutjanines in the Americas appears to have occurred primarily in the western Atlantic Ocean (Caribbean Sea) and been aided by an early Miocene eastward-flowing current and by more optimal lutjanine habitat in the warmer Caribbean waters. Five geminate species pairs in five, strongly supported clades were identified. In three, the trans-isthmian geminate species in the eastern Pacific belonged to clades in which basal and other members of the clade are endemic to the western Atlantic, suggesting that the ancestor to each species geminate pair dispersed westward into the eastern Pacific prior to closure of connections between the two oceans; the opposite occurred in one of the clades. The fifth clade contained only two species, one on either side of the Isthmus. Diversification in life-history and other traits in each geminate species pair appears to have been slight. Five lutjanine species possessing horizontal blue stripes (the blue-lined complex) and distributed from the western Indian Ocean to the eastern Pacific formed a strongly supported monophyletic clade. The lone blue-lined species in the eastern Pacific (<i>Lutjanus viridis</i>) could be conspecific with its highly dispersive sister species (<i>Lutjanus kasmira</i>) from the Indo-Pacific. The chronology of lutjanine diversification and closure of seawater exchange between the two oceans is briefly discussed.
DOI: 10.6084/m9.figshare.1569838.v1
title: Diffusion Indexes with Sparse Loadings

description: The use of large-dimensional factor models in forecasting has received much attention in the literature with the consensus being that improvements on forecasts can be achieved when comparing with standard models. However, recent contributions in the literature have demonstrated that care needs to be taken when choosing which variables to include in the model. A number of different approaches to determining these variables have been put forward. These are, however, often based on ad-hoc procedures or abandon the underlying theoretical factor model.In this paper we will take a different approach to the problem by using the LASSO as a variable selection method to choose between the possible variables and thus obtain sparse loadings from which factors or diffusion indexes can be formed. This allows us to build a more parsimonious factor model which is better suited for forecasting compared to the traditional principal components (PC) approach. We provide an asymptotic analysis of the estimator and illustrate its merits empirically in a forecasting experiment based on US macroeconomic data. Overall we find that compared to PC we obtain improvements in forecasting accuracy and thus find it to be an important alternative to PC.
DOI: 10.6084/m9.figshare.1569840.v2
title: Brownian Integrated Covariance Functions for Gaussian Process Modeling: Sigmoidal Versus Localized Basis Functions

description: Gaussian process modeling, or kriging, is a popular method for modeling data from deterministic computer simulations, and the most common choices of covariance function are Gaussian, power exponential, and Matérn. A characteristic of these covariance functions is that the basis functions associated with their corresponding response predictors are localized, in the sense that they decay to zero as the input location moves away from the simulated input sites. As a result, the predictors tend to revert to the prior mean, which can result in a bumpy fitted response surface. In contrast, a fractional Brownian field model results in a predictor with basis functions that are nonlocalized and more sigmoidal in shape, although it suffers from drawbacks such as inability to represent smooth response surfaces. We propose a class of Brownian integrated covariance functions obtained by incorporating an integrator (as in the white noise integral representation of a fractional Brownian field) into any stationary covariance function. Brownian integrated covariance models result in predictor basis functions that are nonlocalized and sigmoidal, but they are capable of modeling smooth response surfaces. We discuss fundamental differences between Brownian integrated and other covariance functions, and we illustrate by comparing Brownian integrated power exponential with regular power exponential kriging models in a number of examples. Supplementary materials for this article are available online.
DOI: 10.6084/m9.figshare.1569838.v2
title: Diffusion Indexes with Sparse Loadings

description: The use of large-dimensional factor models in forecasting has received much attention in the literature with the consensus being that improvements on forecasts can be achieved when comparing with standard models. However, recent contributions in the literature have demonstrated that care needs to be taken when choosing which variables to include in the model. A number of different approaches to determining these variables have been put forward. These are, however, often based on ad-hoc procedures or abandon the underlying theoretical factor model. In this paper we will take a different approach to the problem by using the LASSO as a variable selection method to choose between the possible variables and thus obtain sparse loadings from which factors or diffusion indexes can be formed. This allows us to build a more parsimonious factor model which is better suited for forecasting compared to the traditional principal components (PC) approach. We provide an asymptotic analysis of the estimator and illustrate its merits empirically in a forecasting experiment based on US macroeconomic data. Overall we find that compared to PC we obtain improvements in forecasting accuracy and thus find it to be an important alternative to PC.
DOI: 10.6084/m9.figshare.1569838.v3
title: Diffusion Indexes With Sparse Loadings

description: The use of large-dimensional factor models in forecasting has received much attention in the literature with the consensus being that improvements on forecasts can be achieved when comparing with standard models. However, recent contributions in the literature have demonstrated that care needs to be taken when choosing which variables to include in the model. A number of different approaches to determining these variables have been put forward. These are, however, often based on ad hoc procedures or abandon the underlying theoretical factor model. In this article, we will take a different approach to the problem by using the least absolute shrinkage and selection operator (LASSO) as a variable selection method to choose between the possible variables and thus obtain sparse loadings from which factors or diffusion indexes can be formed. This allows us to build a more parsimonious factor model that is better suited for forecasting compared to the traditional principal components (PC) approach. We provide an asymptotic analysis of the estimator and illustrate its merits empirically in a forecasting experiment based on U.S. macroeconomic data. Overall we find that compared to PC we obtain improvements in forecasting accuracy and thus find it to be an important alternative to PC. Supplementary materials for this article are available online.
DOI: 10.6084/m9.figshare.1569840.v1
title: Brownian Integrated Covariance Functions for Gaussian Process Modeling: Sigmoidal Versus Localized Basis Functions

description: ABSTRACTGaussian process modeling, or kriging, is a popular method for modeling data from deterministic computer simulations, and the most common choices of covariance function are Gaussian, power exponential, and Matérn. A characteristic of these covariance functions is that the basis functions associated with their corresponding response predictors are localized, in the sense that they decay to zero as the input location moves away from the simulated input sites. As a result, the predictors tend to revert to the prior mean, which can result in a bumpy fitted response surface. In contrast, a fractional Brownian field model results in a predictor with basis functions that are nonlocalized and more sigmoidal in shape, although it suffers from drawbacks such as inability to represent smooth response surfaces. We propose a class of Brownian integrated covariance functions obtained by incorporating an integrator (as in the white noise integral representation of a fractional Brownian field) into any stationary covariance function. Brownian integrated covariance models result in predictor basis functions that are nonlocalized and sigmoidal, but they are capable of modeling smooth response surfaces. We discuss fundamental differences between Brownian integrated and other covariance functions, and we illustrate by comparing Brownian integrated power exponential with regular power exponential kriging models in a number of examples.