bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Long‐term Trends in Tropospheric Ozone Levels
Authors: Smith Michael , Yau Paul , Shively Thomas , Kohn Robert 
Published: May 2007

SummaryThis paper develops Bayesian methodology for estimating long‐term trends in the daily maxima of tropospheric ozone. The methods are then applied to study long‐term trends in ozone at six monitoring sites in the state of Texas. The methodology controls for the effects of meteorological variables because it is known that variables such as temperature, wind speed and humidity substantially affect the formation of tropospheric ozone. A semiparametric regression model is estimated in which a nonparametric trivariate surface is used to model the relationship between ozone and these meteorological variables because, while it is known that the relatinship is a complex nonlinear one, its functional form is unknown. The model also allows for the effects of wind direction and seasonality. The errors are modeled as an autoregression, which is methodologically challenging because the observations are unequally spaced over time. Each function in the model is represented as a linear combination of basis functions located at all of the design points. We also estimate an appropriate data transformation simulataneously with the functions. The functions are estimated nonparametrically by a Bayesian hierarchical model that uses indicator variables to allow a non‐zero probability that the coefficient of each basis term is zero. The entire model, including the nonparametric surfaces, data transformation and autoregression for the unequally spaced errors, is estimated using a Markov chain Monte Carlo sampling scheme with a computationally efficient transition kernel for generating the indicator variables. The empirical results indicate that key meteorological variables explain most of the variation in daily ozone maxima through a nonlinear interaction and that their effects are consistent across the six sites. However, the estimated trends vary considerably from site to site, even within the same city.
Small Area Estimation‐New Developments and Directions
Authors: Pfeffermann Danny 
Published: May 2007

SummaryThe purpose of this paper is to provide a critical review of the main advances in small area estimation (SAE) methods in recent years. We also discuss some of the earlier developments, which serve as a necessary background for the new studies. The review focuses on model dependent methods with special emphasis on point prediction of the target area quantities, and mean square error assessments. The new models considered are models used for discrete measurements, time series models and models that arise under informative sampling. The possible gains from modeling the correlations among small area random effects used to represent the unexplained variation of the small area target quantities are examined. For review and appraisal of the earlier methods used for SAE, see Ghosh & Rao (1994).
Influence Diagrams for Causal Modelling and Inference
Authors: Dawid A. P. 
Published: May 2007

SummaryWe consider a variety of ways in which probabilistic and causal models can be represented in graphical form. By adding nodes to our graphs to represent parameters, decision,etc., we obtain a generalisation of influence diagrams that supports meaningful causal modelling and inference, and only requires concepts and methods that are already standard in the purely probabilistic case. We relate our representations to others, particularly functional models, and present arguments and examples in favour of their superiority.
Bayesian MCMC Mapping of Quantitative Trait Loci in a Half‐sib Design: a Graphical Model Perspective
Authors: Sheehan N.A. , Gulbrandtsen B. , Lund M.S. , Sorensen D.A. 
Published: May 2007

SummaryGraphical models provide a powerful and flexible approach to the analysis of complex problems in genetics. While task‐specific software may be extremely efficient for any particular analysis, it is often difficult to adapt to new computational challenges. By viewing these genetic applications in a more general framework, many problems can be handled by essentially the same software. This is advantageous in an area where fast methodological development is essential. Once a method has been fully developed and tested, problem‐specific software may then be required. The aim of this paper is to illustrate the potential use of a graphical model approach to genetic analyses by taking a very simple and well‐understood problem by way of example.
Randomized Response, Statistical Disclosure Control and Misclassificatio: a Review
Authors: van den Hout Ardo , van der Heijden Peter G.M. 
Published: May 2007

SummaryThis paper discusses analysis of categorical data which have been misclassified and where misclassification probabilities are known. Fields where this kind of misclassification occurs are randomized response, statistical disclosure control, and classification with known sensitivity and specificity. Estimates of true frequencies are given, and adjustments to the odds ratio are discussed. Moment estimates and maximum Likelihood estimates are compared and it is proved that they are the same in the interior of the parameter space. Since moment estimators are regularly outside the parameter space, special attention is paid to the possibility of boundary solutions. An example is given.
The Effect of using Household as a Sampling Unit
Authors: Clark Robert G. , Steel David G. 
Published: May 2007

SummaryThe effect of sampling people through households is considered. Results on design effects for two stage surveys are reviewed and applied to give design effects of household samples. The main factors that determine the design effect are identified for the designs in which one person, or all people, are selected from each selected household. Within household correlation is one factor. We show that the relationships between household size and the mean and variance within households are also important factors. Census and survey data are used to empirically compare the design effects for a range estimators, variables and designs.
RESIDUAL PROPERTIES OF FREE PRO-P GROUPS
Authors: BARNEA YIFTACH 
Published: May 2007

Recall that if S is a class of groups, then a group G is residually-S if,
for any element 1 ≠ g ∈ G, there is a normal subgroup
N of G such that g ∉ N and G/N ∈ S.
Let Λ be a commutative Noetherian local pro-p ring, with a maximal ideal M.
Recall that the first congruence subgroup of SLd(Λ) is:
SL1d(Λ)
= ker (SLd(Λ) → SLd(Λ/M)).Let K ⊆ ℕ. We define SΛ(K)
= ∪d∈K{open subgroups of SL1d(Λ)}.
We show that if K is infinite, then for Λ = [ ]p[[t]]
and for Λ = ℤp a finitely generated non-abelian free pro-p group is
residually-SΛ(K). We
apply a probabilistic method, combined with Lie methods and a result on random generation in simple
algebraic groups over local fields. It is surprising that the case of zero characteristic is deduced from the
positive characteristic case.
ASYMPTOTICALLY SHARP BOUNDS IN THE HARDY–LITTLEWOOD INEQUALITIES ON MEAN VALUES OF ANALYTIC FUNCTIONS
Authors: AVKHADIEV F. G. , WIRTHS K.-J. 
Published: May 2007

Let f be analytic in the unit disc, and let it belong to the Hardy space Hp, equipped with the usual norm ∥f∥p. It is known from the work of Hardy and Littlewood that for q > p, the constants[formula here]with the usual extension to the case where q = ∞, have C(p, q) < ∞ .The authors prove that[formula here]and[formula here]
A BRAIDED SIMPLICIAL GROUP
Authors: WU JIE 
Published: May 2007

By studying the braid group action on Milnor's construction of the 1-sphere, we show that the general higher homotopy group of the 3-sphere is the fixed set of the pure braid group action on certain combinatorially described groups. This establishes a relation between the braid groups and the homotopy groups of the sphere.2000Mathematical Subject Classification: 20F36, 55P35, 55Q05, 55Q40, 55U10.
ALMOST FRÉCHET DIFFERENTIABILITY OF LIPSCHITZ MAPPINGS BETWEEN INFINITE-DIMENSIONAL BANACH SPACES
Authors: JOHNSON WILLIAM B. , LINDENSTRAUSS JORAM , PREISS DAVID , SCHECHTMAN GIDEON 
Published: May 2007

We give several sufficient conditions on a pair of Banach spaces X and Y under which each Lipschitz mapping from a domain in X to Y has, for every $\epsilon > 0$, a point of $\epsilon$-Fréchet differentiability. Most of these conditions are stated in terms of the moduli of asymptotic smoothness and convexity, notions which have appeared in the literature under a variety of names. We prove, for example, that for $\infty > r > p \ge 1$, every Lipschitz mapping from a domain in an $\ell_r$-sum of finite-dimensional spaces into an $\ell_p$-sum of finite-dimensional spaces has, for every $\epsilon > 0$, a point of $\epsilon$-Fréchet differentiability, and that every Lipschitz mapping from an asymptotically uniformly smooth space to a finite-dimensional space has such points. The latter result improves, with a simpler proof, an earlier result of the second and third authors. We also survey some of the known results on the notions of asymptotic smoothness and convexity, prove some new properties, and present some new proofs of existing results.2000 Mathematical Subject Classification: 46G05, 46T20.
SYMMETRY GROUP ANALYSIS OF WEAK SOLUTIONS
Authors: ĐAPIĆ N. , KUNZINGER M. , PILIPOVIĆ S. 
Published: May 2007

Methods of Lie group analysis of differential equations are extended to weak solutions of (linear and non-linear) partial differential equations, where the term `weak solution' comprises the following settings: distributional solutions; solutions in generalized function algebras; solutions in the sense of association (corresponding to a number of weak or integral solution concepts in classical analysis). Factorization properties and infinitesimal criteria that allow the treatment of all three settings simultaneously are developed, thereby unifying and extending previous work in this area.2000 Mathematical Subject Classification: 46F30, 22E70, 35Dxx, 35A30.
ON ARTIN'S CONJECTURE, II: PAIRS OF ADDITIVE FORMS
Authors: BRÜDERN J. , GODINHO H. 
Published: May 2007

It is shown that the system of two additive equations a_1 x_1^k + \ldots + a_s x_s^k = b_1 x_1^k + \ldots + b_s x_s^k =0 where $k \ge 2$ and $a_j$, $b_j$ are any given integers, has non-trivial solutions in all $p$-adic fields provided only that $s > 8k^2$. The constant 8 can be reduced when $k$ is not a power of 2. It is expected, in accordance with a classical conjecture of Artin, that the bound $8k^2$ can be replaced by $2k^2$.2000 Mathematical Subject Classification:11D72.
Use of portable ultrasonography as a nondestructive method for estimating reproductive effort in lizards
Authors: Gilman Casey A. , Wolf Blair O. 
Published: May 2007

SUMMARYObtaining population-level life history data such as egg and clutch size in reptiles has most often required that individuals be sacrificed. This prevents a reexamination of individuals over intra-annual and inter-annual time scales,limiting insight into the effects of varying environmental conditions on reproductive output. Here, we test the use of a laptop-sized portable ultrasound imaging system as a nondestructive means for quantifying reproductive investment in five species of lizards with a range of body sizes,forms and life histories. Ultrasound scans produced egg counts that were accurate for clutch sizes of two to seven eggs, and provided good estimates(within 5.5±1.69 eggs, mean ± s.e.m., relative error 21%) for clutch sizes of between 18 and 41 eggs. Egg measurements using virtual calipers produced average egg volumes that deviated from actual volumes by 0.09±0.01 cm3 (relative error 25.9%), and estimated clutch volumes that differed from actual volumes by 1.03±0.26 cm3(relative error 29.5%). We also monitored development in five lizard species and found that changes in follicle and egg size and degree of embryonic development can be measured over periods of just a few days.
Low speed maneuvering flight of the rose-breasted cockatoo (Eolophus roseicapillus). I. Kinematic and neuromuscular control of turning
Authors: Hedrick T. L. , Biewener A. A. 
Published: May 2007

SUMMARYManeuvering flight has long been recognized as an important component of the natural behavior of many bird species, but has been the subject of little experimental work. Here we examine the kinematics and neuromuscular control of turning flight in the rose-breasted cockatoo Eolophus roseicapillus(N=6), testing predictions of maneuvering flight and control based on aerodynamic theory and prior kinematic and neuromuscular studies. Six cockatoos were trained to navigate between two perches placed in an L-shaped flight corridor, making a 90° turn midway through each flight. Flights were recorded with three synchronized high-speed video cameras placed outside the corridor, allowing a three-dimensional reconstruction of wing and body kinematics through the turn. We simultaneously collected electromyography recordings from bilateral implants in the pectoralis, supracoracoideus, biceps brachii and extensor metacarpi radialis muscles. The cockatoos maneuvered using flapping, banked turns with an average turn radius of 0.92 m. The mean rate of change in heading during a complete wingbeat varied through the turn and was significantly correlated to roll angle at mid-downstroke. Changes in roll angle were found to include both within-wingbeat and among-wingbeat components that bear no direct relationship to one another. Within-wingbeat changes in roll were dominated by the inertial effects while among-wingbeat changes in roll were likely the result of both inertial and aerodynamic effects.
Low speed maneuvering flight of the rose-breasted cockatoo (Eolophus roseicapillus). II. Inertial and aerodynamic reorientation
Authors: Hedrick T. L. , Usherwood J. R. , Biewener A. A. 
Published: May 2007

SUMMARYThe reconfigurable, flapping wings of birds allow for both inertial and aerodynamic modes of reorientation. We found evidence that both these modes play important roles in the low speed turning flight of the rose-breasted cockatoo Eolophus roseicapillus. Using three-dimensional kinematics recorded from six cockatoos making a 90° turn in a flight corridor, we developed predictions of inertial and aerodynamic reorientation from estimates of wing moments of inertia and flapping arcs, and a blade-element aerodynamic model. The blade-element model successfully predicted weight support(predicted was 88±17% of observed, N=6) and centripetal force(predicted was 79±29% of observed, N=6) for the maneuvering cockatoos and provided a reasonable estimate of mechanical power. The estimated torque from the model was a significant predictor of roll acceleration (r2=0.55, P&lt;0.00001), but greatly overestimated roll magnitude when applied with no roll damping. Non-dimensional roll damping coefficients of approximately –1.5,2–6 times greater than those typical of airplane flight dynamics(approximately –0.45), were required to bring our estimates of reorientation due to aerodynamic torque back into conjunction with the measured changes in orientation. Our estimates of inertial reorientation were statistically significant predictors of the measured reorientation within wingbeats (r2 from 0.2 to 0.37, P&lt;0.0005). Components of both our inertial reorientation and aerodynamic torque estimates correlated, significantly, with asymmetries in the activation profile of four flight muscles: the pectoralis, supracoracoideus, biceps brachii and extensor metacarpi radialis (r2 from 0.27 to 0.45, P&lt;0.005). Thus, avian flight maneuvers rely on production of asymmetries throughout the flight apparatus rather than in a specific set of control or turning muscles.
Molecular and cellular studies in evolutionary physiology of natural vertebrate populations: influences of individual variation and genetic components on sampling and measurements
Authors: Nikinmaa Mikko , Waser Wolfgang 
Published: May 2007

SUMMARYStudies combining ecological, genetic and physiological approaches are needed in evolutionary biology. Although the combination of approaches has been emphasized, such studies have been rare with regard to molecular and cellular studies on natural vertebrate populations. The major reasons for this are that the generation time of vertebrates is long and it is difficult to find a molecular or cell physiological measurement that is both relevant for the fitness of the population and can be repeated an adequate number of times to enable estimations of individual variability. The paucity of suitable physiological parameters is partly due to the fact that most physiological studies have not been directed towards understanding the behaviour of populations but towards understanding the basic mechanisms of the function of individuals. Also, physiological measurements that appear most relevant from the point of view of evolutionary studies are often integrative functions,composed of the function of many genes. When dissecting the integrative functions into components, it is often observed that the same integrative response can be achieved via different routes, i.e. changes in the responses of different genes. To enable cellular and molecular physiological studies to be increasingly combined with ecological and genetic studies, it is important that such studies include and report individual variability and that the sample size is increased. In addition, more sophisticated statistical methods should be used than is traditionally done, and when the function of most genes in the integrative response are not known, techniques such as QTL mapping should be used. Hitherto in vertebrates, the methodology has mainly been used in production biology (e.g. meat or milk production). With regard to combining genomic and physiological studies, one must bear in mind that the massive datasets associated with genomic studies need to be further enlarged to enable estimates of individual variation. It is also important to remember that microarray and proteomic data give the levels of mRNA and proteins,respectively. Since the function of the protein can be regulated independently of its transcription or its level in the cell, direct physiological measurements are also needed if estimations of protein activity in the individuals of a population are wanted.
Responses to hypoxia and recovery: repayment of oxygen debt is not associated with compensatory protein synthesis in the Amazonian cichlid,Astronotus ocellatus
Authors: Lewis J. M. , Costa I. , Val A. L. , Almeida-Val V. M. F. , Gamperl A. K. , Driedzic W. R. 
Published: May 2007

SUMMARYOxygen consumption, as an indicator of routine metabolic rate (RoMR), and tissue-specific changes in protein synthesis, as measured by 3H-labelled phenylalanine incorporation rates, were determined in Astronotus ocellatus to investigate the cellular mechanisms behind hypoxia-induced metabolic depression and recovery. RoMR was significantly depressed, by approximately 50%, when dissolved oxygen levels reached 10%saturation (0.67±0.01 mg l–1 at 28±1°C). This depression in RoMR was accompanied by a 50–60% decrease in liver,heart and gill protein synthesis, but only a 30% decrease in brain protein synthesis. During recovery from hypoxia, an overshoot in RoMR to 270% of the normoxic rate was observed, indicating the accumulation of an oxygen debt during hypoxia. This conclusion was consistent with significant increase in plasma lactate levels during the hypoxic exposure, and the fact that lactate levels rapidly returned to pre-hypoxic levels. In contrast, a hyperactivation of protein synthesis did not occur, suggesting the overshoot in oxygen consumption during recovery is attributed to an increase in cellular processes other than protein synthesis.
Validation of vertical ground reaction forces on individual limbs calculated from kinematics of horse locomotion
Authors: Bobbert Maarten F. , Álvarez Constanza B. Gómez , van Weeren P. René , Roepstorff Lars , Weishaupt Michael A. 
Published: May 2007

SUMMARYThe purpose of this study was to determine whether individual limb forces could be calculated accurately from kinematics of trotting and walking horses. We collected kinematic data and measured vertical ground reaction forces on the individual limbs of seven Warmblood dressage horses, trotting at 3.4 m s–1 and walking at 1.6 m s–1 on a treadmill. First, using a segmental model, we calculated from kinematics the total ground reaction force vector and its moment arm relative to each of the hoofs. Second, for phases in which the body was supported by only two limbs, we calculated the individual reaction forces on these limbs. Third, we assumed that the distal limbs operated as linear springs, and determined their force–length relationships using calculated individual limb forces at trot. Finally, we calculated individual limb force–time histories from distal limb lengths. A good correspondence was obtained between calculated and measured individual limb forces. At trot, the average peak vertical reaction force on the forelimb was calculated to be 11.5±0.9 N kg–1 and measured to be 11.7±0.9 N kg–1, and for the hindlimb these values were 9.8±0.7 N kg–1 and 10.0±0.6 N kg–1,respectively. At walk, the average peak vertical reaction force on the forelimb was calculated to be 6.9±0.5 N kg–1 and measured to be 7.1±0.3 N kg–1, and for the hindlimb these values were 4.8±0.5 N kg–1 and 4.7±0.3 N kg–1, respectively. It was concluded that the proposed method of calculating individual limb reaction forces is sufficiently accurate to detect changes in loading reported in the literature for mild to moderate lameness at trot.
Phosphatidylcholine profile-mediated group recognition in catfish
Authors: Matsumura Koichi , Matsunaga Shigeki , Fusetani Nobuhiro 
Published: May 2007

SUMMARYAnimal groups are integrated by emission of discrete signals from members,so-called social signals, which have evolved for each species. Among communication signals, chemical signals play an important role for recognition of group membership. The catfish Plotosus lineatus forms a dense school immediately after hatching, and school recognition is under the control of chemical signals emitted by the school members. The key substance(s)governing this recognition are deduced to be a mixture of phosphatidylcholines(PC). To substantiate this hypothesis that a mixture of PC molecular species functions as recognition of school-specific odor, we examined the ability of P. lineatus to discriminate between familiar and unfamiliar PCs. P. lineatus responded only to PCs from a familiar school, and not to those from unfamiliar schools. PC molecular species were then analyzed by quantitative high performance liquid chromatography, which resulted in not only a complex mixture of PC molecular species, but also school-specific PC profiles. Furthermore, multivariate analysis of the quantified PC peaks revealed the presence of various PC profiles. Finally, we showed that the modification of PC profiles disrupts the recognition of school odor in P. lineatus. Therefore, we conclude that the recognition of school odor in P. lineatus is governed by school-specific PC profiles.
Wet Chemical Preparation of Well-dispersed Colloidal Cerium Oxide Nanocrystals
Authors: Liu Yulan , He Shengtai , Uehara Masato , Maeda Hideaki 
Published: May 2007

Abstract
In this study, a simple one-step wet chemical method was presented to prepare colloidal cerium oxide, CeO2, nanocrystals. By a direct decomposition of cerium(IV) ammonium nitrate in a solution of 1-octadecene and oleylamine at 180 °C, well-dispersed CeO2 nanoparticle colloid, with an average size of about 4.5 nm, was obtained.