bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive Lagrange–Galerkin methods for unsteady convection-diffusion problems
Authors: Houston Paul , Süli Endre
Published: July 2005

In this paper we derive an a posteriori error bound for the Lagrange–Galerkin discretisation of an unsteady (linear) convection-diffusion problem, assuming only that the underlying space-time mesh is nondegenerate. The proof of this error bound is based on strong stability estimates of an associated dual problem, together with the Galerkin orthogonality of the finite element method. Based on this a posteriori bound, we design and implement the corresponding adaptive algorithm to ensure global control of the error with respect to a user-defined tolerance.
On simple double zeros and badly conditioned zeros of analytic functions of 𝑛 variables
Authors: Dedieu Jean-Pierre , Shub Mike
Published: July 2005

We give a numerical criterion for a badly conditioned zero of a system of analytic equations to be part of a cluster of two zeros.
Exhaustive determination of (1023, 511, 255)-cyclic difference sets
Authors: Gaal Peter , Golomb Solomon
Published: July 2005

An exhaustive search for (1023, 511, 255)-cyclic difference sets has been conducted. A total of 10 non-equivalent (1023, 511, 255)-cyclic difference sets have been found, all of which are members of previously known or conjectured infinite families. A fast and effective autocorrelation test method was utilized that can also facilitate the testing of longer sequences.
Constructing fully symmetric cubature formulae for the sphere
Authors: Heo Sangwoo , Xu Yuan
Published: July 2005

We construct symmetric cubature formulae of degrees in the 13-39 range for the surface measure on the unit sphere. We exploit a recently published correspondence between cubature formulae on the sphere and on the triangle. Specifically, a fully symmetric cubature formula for the surface measure on the unit sphere corresponds to a symmetric cubature formula for the triangle with weight function

(

u

1

u

2

u

3

)

−
1

/

2

(u_{1}u_{2}u_{3})^{-1/2}

, where

u

1

u_{1}

,

u

2

u_{2}

, and

u

3

u_{3}

are homogeneous coordinates.
Weak approximations. A Malliavin calculus approach
Authors: Kohatsu-Higa Arturo
Published: July 2005

We introduce a variation of the proof for weak approximations that is suitable for studying the densities of stochastic processes which are evaluations of the flow generated by a stochastic differential equation on a random variable that may be anticipating. Our main assumption is that the process and the initial random variable have to be smooth in the Malliavin sense. Furthermore, if the inverse of the Malliavin covariance matrix associated with the process under consideration is sufficiently integrable, then approximations for densities and distributions can also be achieved. We apply these ideas to the case of stochastic differential equations with boundary conditions and the composition of two diffusions.
Testing multivariate uniformity and its applications
Authors: Liang Jia-Juan , Fang Kai-Tai , Hickernell Fred , Li Runze
Published: July 2005

Some new statistics are proposed to test the uniformity of random samples in the multidimensional unit cube[0,1]d (d≥2).[0,1]^d\ (d\ge 2).These statistics are derived from number-theoretic or quasi-Monte Carlo methods for measuring the discrepancy of points in[0,1]d[0,1]^d. Under the null hypothesis that the samples are independent and identically distributed with a uniform distribution in[0,1]d[0,1]^d, we obtain some asymptotic properties of the new statistics. By Monte Carlo simulation, it is found that the finite-sample distributions of the new statistics are well approximated by the standard normal distribution,N(0,1)N(0,1), or the chi-squared distribution,χ2(2)\chi ^2(2). A power study is performed, and possible applications of the new statistics to testing general multivariate goodness-of-fit problems are discussed.
Enumerating solutions to 𝑝(𝑎)+𝑞(𝑏)=𝑟(𝑐)+𝑠(𝑑)
Authors: Bernstein Daniel
Published: July 2005

Letp,q,r,sp,q,r,sbe polynomials with integer coefficients. This paper presents a fast method, using very little temporary storage, to find all small integers(a,b,c,d)(a,b,c,d)satisfyingp(a)+q(b)=r(c)+s(d)p(a)+q(b)=r(c)+s(d). Numerical results include all small solutions toa4+b4+c4=d4a^4+b^4+c^4=d^4; all small solutions toa4+b4=c4+d4a^4+b^4=c^4+d^4; and the smallest positive integer that can be written in55ways as a sum of two coprime cubes.
Convergence of numerical schemes for the solution of parabolic stochastic partial differential equations
Authors: Davie A. , Gaines J.
Published: July 2005

We consider the numerical solution of the stochastic partial differential equation
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="partial-differential u slash partial-differential t equals partial-differential squared u slash partial-differential x squared plus sigma left-parenthesis u right-parenthesis ModifyingAbove upper W With dot left-parenthesis x comma t right-parenthesis">

∂
u

/

∂
t

=

∂
2

u

/

∂

x
2

+
σ
(
u
)

W
˙

(
x
,
t
)

{\partial u}/{\partial t}={\partial ^2u}/{\partial x^2}+\sigma (u)\dot {W}(x,t)

, where

W
˙

\dot {W}

is space-time white noise, using finite differences. For this equation Gyöngy has obtained an estimate of the rate of convergence for a simple scheme, based on integrals of

W
˙

\dot {W}

over a rectangular grid. We investigate the extent to which this order of convergence can be improved, and find that better approximations are possible for the case of additive noise (

σ
(
u
)
=
1

\sigma (u)=1

) if we wish to estimate space averages of the solution rather than pointwise estimates, or if we are permitted to generate other functionals of the noise. But for multiplicative noise (

σ
(
u
)
=
u

\sigma (u)=u

) we show that no such improvements are possible.
Numerical indefinite integration of functions with singularities
Authors: Jang Aeyoung , Haber Seymour
Published: July 2005

We derive an indefinite quadrature formula, based on a theorem of Ganelius, for

H
p

H^p

functions, for

p
>
1

p>1

, over the interval

(
−
1
,
1
)

(-1,1)

. The main factor in the error of our indefinite quadrature formula is

O
(

e

−
π

N

/

q

)

O(e^{-\pi \sqrt {N/ q}})

, with

2
N

2 N

nodes and

1
p

+

1
q

=
1

\frac 1 p +\frac 1q=1

. The convergence rate of our formula is better than that of the Stenger-type formulas by a factor of

2

\sqrt {2}

in the constant of the exponential. We conjecture that our formula has the best possible value for that constant. The results of numerical examples show that our indefinite quadrature formula is better than Haber’s indefinite quadrature formula for

H
p

H^p

-functions.
Fast convergence of quasi-Monte Carlo for a class of isotropic integrals
Authors: Papageorgiou A.
Published: July 2005

We consider the approximation of

d
d

-dimensional weighted integrals of certain isotropic functions. We are mainly interested in cases where

d
d

is large. We show that the convergence rate of quasi-Monte Carlo for the approximation of these integrals is

O
(

log
⁡
n

/

n
)

O(\sqrt {\log n}/n)

. Since this is a worst case result, compared to the expected convergence rate

O
(

n

−
1

/

2

)

O(n^{-1/2})

of Monte Carlo, it shows the superiority of quasi-Monte Carlo for this type of integral. This is much faster than the worst case convergence,

O
(

log
d

⁡
n

/

n
)

O(\log ^d n/n)

, of quasi-Monte Carlo.
A new class of radial basis functions with compact support
Authors: Buhmann M.
Published: July 2005

Radial basis functions are well-known and successful tools for the interpolation of data in many dimensions. Several radial basis functions of compact support that give rise to nonsingular interpolation problems have been proposed, and in this paper we study a new, larger class of smooth radial functions of compact support which contains other compactly supported ones that were proposed earlier in the literature.
Adaptive wavelet methods for elliptic operator equations: Convergence rates
Authors: Cohen Albert , Dahmen Wolfgang , DeVore Ronald
Published: July 2005

This paper is concerned with the construction and analysis of wavelet-based adaptive algorithms for the numerical solution of elliptic equations. These algorithms approximate the solutionuuof the equation by a linear combination ofNNwavelets. Therefore, a benchmark for their performance is provided by the rate of best approximation touuby an arbitrary linear combination ofNNwavelets (so calledNN-term approximation), which would be obtained by keeping theNNlargest wavelet coefficients of the real solution (which of course is unknown). The main result of the paper is the construction of an adaptive scheme which produces an approximation touuwith errorO(N−s)O(N^{-s})in the energy norm, whenever such a rate is possible byNN-term approximation. The range ofs>0s>0for which this holds is only limited by the approximation properties of the wavelets together with their ability to compress the elliptic operator. Moreover, it is shown that the number of arithmetic operations needed to compute the approximate solution stays proportional toNN. The adaptive algorithm applies to a wide class of elliptic problems and wavelet bases. The analysis in this paper puts forward new techniques for treating elliptic problems as well as the linear systems of equations that arise from the wavelet discretization.
Error bounds for interpolatory quadrature rules on the unit circle
Authors: Santos-León J.
Published: July 2005

For the construction of an interpolatory integration rule on the unit circle

T
T

with

n
n

nodes by means of the Laurent polynomials as basis functions for the approximation, we have at our disposal two nonnegative integers

p
n

p_n

and

q
n

,

q_n,

p
n

+

q
n

=
n
−
1
,

p_n+q_n=n-1,

which determine the subspace of basis functions. The quadrature rule will integrate correctly any function from this subspace. In this paper upper bounds for the remainder term of interpolatory integration rules on

T
T

are obtained. These bounds apply to analytic functions up to a finite number of isolated poles outside

T
.

T.

In addition, if the integrand function has no poles in the closed unit disc or is a rational function with poles outside

T
T

, we propose a simple rule to determine the value of

p
n

p_n

and hence

q
n

q_n

in order to minimize the quadrature error term. Several numerical examples are given to illustrate the theoretical results.
Transformation of hypersingular integrals and black-box cubature
Authors: Sauter S. , Lage C.
Published: July 2005

In this paper, we will consider hypersingular integrals as they arise by transforming elliptic boundary value problems into boundary integral equations. First, local representations of these integrals will be derived. These representations contain so-called finite-part integrals. In the second step, these integrals are reformulated as improper integrals. We will show that these integrals can be treated by cubature methods for weakly singular integrals as they exist in the literature.
Weakened acute type condition for tetrahedral triangulations and the discrete maximum principle
Authors: Korotov Sergey , Křížek Michal , Neittaanmäki Pekka
Published: July 2005

We prove that a discrete maximum principle holds for continuous piecewise linear finite element approximations for the Poisson equation with the Dirichlet boundary condition also under a condition of the existence of some obtuse internal angles between faces of terahedra of triangulations of a given space domain. This result represents a weakened form of the acute type condition for the three-dimensional case.
Error estimates in the numerical evaluation of some BEM singular integrals
Authors: Mastroianni G. , Monegato G.
Published: July 2005

In some applications of Galerkin boundary element methods one has to compute integrals which, after proper normalization, are of the form

∫

a

b

∫

−
1

1

f
(
x
,
y
)

x
−
y

d
x
d
y
,

\begin{equation*}\int _{a}^{b}\int _{-1}^{1}\frac {f(x,y)}{{x-y}}dxdy,\end{equation*}

where

(
a
,
b
)
≡
(
−
1
,
1
)

(a,b)\equiv (-1,1)

, or

(
a
,
b
)
≡
(
a
,
−
1
)

(a,b)\equiv (a,-1)

, or

(
a
,
b
)
≡
(
1
,
b
)

(a,b)\equiv (1,b)

, and

f
(
x
,
y
)

f(x,y)

is a smooth function. In this paper we derive error estimates for a numerical approach recently proposed to evaluate the above integral when a

p
−

p-

, or

h
−
p

h-p

, formulation of a Galerkin method is used. This approach suggests approximating the inner integral by a quadrature formula of interpolatory type that exactly integrates the Cauchy kernel, and the outer integral by a rule which takes into account the

log
\log

endpoint singularities of its integrand. Some numerical examples are also given.
Explicit upper bounds for exponential sums over primes
Authors: Daboussi Hedi , Rivat Joël
Published: July 2005

We give explicit upper bounds for linear trigonometric sums over primes.
Classification of quintic eutactic forms
Authors: Batut Christian
Published: July 2005

From the classical Voronoi algorithm, we derive an algorithm to classify quadratic positive definite forms by their minimal vectors; we define some new invariants for a class, for which several conjectures are proposed. Applying the algorithm to dimension 5 we obtain the table of the 136 classes in this dimension, we enumerate the 118 eutactic quintic forms, and we verify the Ash formula.
Shape calculus and finite element method in smooth domains
Authors: Tiihonen T.
Published: July 2005

The use of finite elements in smooth domains leads naturally to polyhedral or piecewise polynomial approximations of the boundary. Hence the approximation error consists of two parts: the geometric part and the finite element part. We propose to exploit this decomposition in the error analysis by introducing an auxiliary problem defined in a polygonal domain approximating the original smooth domain. The finite element part of the error can be treated in the standard way. To estimate the geometric part of the error, we need quantitative estimates related to perturbation of the geometry. We derive such estimates using the techniques developed for shape sensitivity analysis.
A two-grid discretization scheme for eigenvalue problems
Authors: Xu Jinchao , Zhou Aihui
Published: July 2005

A two-grid discretization scheme is proposed for solving eigenvalue problems, including both partial differential equations and integral equations. With this new scheme, the solution of an eigenvalue problem on a fine grid is reduced to the solution of an eigenvalue problem on a much coarser grid, and the solution of a linear algebraic system on the fine grid and the resulting solution still maintains an asymptotically optimal accuracy.
Migrating locusts can detect polarized reflections to avoid flying over the sea
Authors: Shashar N , Sabbah S , Aharoni N
Published: July 2005

The desert locustSchistocerca gregariais a well known migrating insect, travelling long distances in swarms containing millions of individuals. During November 2004, such a locust swarm reached the northern coast of the Gulf of Aqaba, coming from the Sinai desert towards the southeast. Upon reaching the coast, they avoided flying over the water, and instead flew north along the coast. Only after passing the tip of the gulf did they turn east again. Experiments with tethered locusts showed that they avoided flying over a light-reflecting mirror, and when given a choice of a non-polarizing reflecting surface and a surface that reflected linearly polarized light, they preferred to fly over the former. Our results suggest that locusts can detect the polarized reflections of bodies of water and avoid crossing them; at least when flying at low altitudes, they can therefore avoid flying over these dangerous areas.
Expression of uncoupling protein and alternative oxidase depends on lipid or carbohydrate substrates in thermogenic plants
Authors: Ito K , Seymour R.S
Published: July 2005

Thermogenesis, in which cellular respiratory activity is considerably stimulated, requires mitochondrial uncoupling protein (UCP) in mammals and an alternative oxidase (AOX) in plants. Here, we show that the genes for both proteins are expressed in thermogenic plants, but the type correlates with the respiratory substrate. A novel gene termed
PsUCPa
encoding a variant of UCP was specifically expressed in thermogenic flowers of
Philodendron selloum
, which uses lipids as substrates. However, a gene termed
DvAOX
encoding for AOX protein was expressed in thermogenic flowers of
Dracunculus vulgaris
, which presumably uses carbohydrates as substrates. These findings suggest that cellular metabolism is a major determinant in selective expression of appropriate thermogenic genes in plants.
Costly parasite resistance: a genotype-dependent handicap in sand lizards?
Authors: Olsson Mats , Wapstra Erik , Madsen Thomas , Ujvari Beata , Rugfelt Carl
Published: July 2005

Male sand lizards (
Lacerta agilis
) with a specific restriction fragment length polymorphism fragment in their major histocompatibility complex (MHC) genotype (‘O-males’) are more resistant to ectoparasites (a tick,
Ixodes ricinus
) than are males that lack this fragment (‘NO-males’). However, emerging evidence suggests that such adaptive immune responses are costly, here manifested by reduced body condition and a compromised defence against secondary infections by haemoprotid parasites that use the ticks as vectors. Subsequent to tick encounter, O-males suffer from a higher leucocyte–erythrocyte ratio, and higher haemoprotid parasitaemia, in particular in relation to vector encounter rate. Furthermore, O-males (i.e. successful tick defenders) with more haemoprotid parasites remaining in their blood stream were in better body condition, whereas this did not apply in NO-males, demonstrating that the adaptive immunoreaction can—in the short term—be energetically even more costly than being moderately parasitized. In agreement with Zahavian handicap theory, O-males had a (marginally) higher reproductive success than males that lacked this fragment.
MHC-assortative facial preferences in humans
Authors: Roberts S. Craig , Little Anthony C , Gosling L. Morris , Jones Benedict C , Perrett David I , Carter Vaughan , Petrie Marion
Published: July 2005

Individuals tend to choose mates who are sufficiently genetically dissimilar to avoid inbreeding. As facial attractiveness is a key factor in human mate preference, we investigated whether facial preferences were related to genetic dissimilarity. We asked female volunteers to rate the attractiveness of men from photographs and compared these results with individual genotypes at the major histocompatibility complex (MHC). In contrast to previously reported preferences based on odour, we found a non-significant tendency for women to rate MHC-similar faces as more attractive, suggesting a preference for cues to a self-similar MHC in faces. Further analysis revealed that male faces received higher attractiveness scores when rated by women who were MHC-similar than by MHC-dissimilar women. Although unexpected, this MHC-similar facial preference is consistent with other studies documenting assortative preferences in humans, including for facial phenotype.
Correlated evolution of maternally derived yolk testosterone and early developmental traits in passerine birds
Authors: Gorman K.B , Williams T.D
Published: July 2005

Recent studies on hormone-mediated maternal effects in birds have highlighted the influence of variable maternal yolk androgen concentration on offspring phenotype, particularly in terms of early development. If genetic differences between laying females regulate variation in yolk hormone concentration, then this physiological maternal effect is an indirect genetic effect which can provide a basis for the co-evolution of maternal and offspring phenotypes. Thus, we investigated the evolutionary associations between maternally derived yolk testosterone (T) and early developmental traits in passerine birds via a comparative, phylogenetic analysis. Our results from species-correlation and independent contrasts analyses provide convergent evidence for the correlated evolution of maternal yolk T concentration and length of the prenatal developmental period in passerines. Here, we show these traits are significantly negatively associated (species-correlation:p<0.001,r2=0.85; independent contrasts:p=0.005). Our results highlight the need for more studies investigating the role of yolk hormones in evolutionary processes concerning maternal effects.
Spatial encoding in mountain chickadees: features overshadow geometry
Authors: Gray Emily R , Bloomfield Laurie L , Ferrey Anne , Spetch Marcia L , Sturdy Christopher B
Published: July 2005

Encoding the global geometric shape of an enclosed environment is a principal means of orientation in human and non-human animals. Animals spontaneously encode the geometry of an enclosure even when featural information is available. Although features can be used, they typically do not overshadow geometry. However, all previously tested organisms have been reared in human-made environments with salient geometrical cues. Here, we show that wild-caught mountain chickadees (
Poecile gambeli
) do not spontaneously encode the geometry of an enclosure when salient features are present near the goal. However, chickadees trained without salient features encode geometric information, but this encoding is overshadowed by features.
Behaviour of leatherback sea turtles,Dermochelys coriacea, during the migratory cycle
Authors: James Michael C , Myers Ransom A , Ottensmeyer C. Andrea
Published: July 2005

Leatherback sea turtles,Dermochelys coriacea, undertake broad oceanic movements. While satellite telemetry has been used to investigate the post-nesting behaviour of female turtles tagged on tropical nesting beaches, long-term behavioural patterns of turtles of different sexes and sizes have not been described. Here we investigate behaviour for 25 subadult and adult male and female turtles satellite-tagged in temperate waters off Nova Scotia, Canada. Although sex and reproductive condition contributed to variation in migratory patterns, the migratory cycle of all turtles included movement between temperate and tropical waters. Marked changes in rates of travel, and diving and surfacing behaviour, accompanied southward movement away from northern foraging areas. As turtles approached higher latitudes the following spring and summer, they assumed behaviours consistent with regular foraging activity and eventually settled in coastal areas off Canada and the northeastern USA. Behavioural patterns corresponding to various phases of the migratory cycle were consistent across multiple animals and were repeated within individuals that completed return movements to northern waters. We consider the potential biological significance of these patterns, including how turtle behaviour relates to predator avoidance, thermoregulation and prey distribution.
Stable isotopes, beaks and predators: a new tool to study the trophic ecology of cephalopods, including giant and colossal squids
Authors: Cherel Yves , Hobson Keith A
Published: July 2005

Cephalopods play a key role in the marine environment but knowledge of their feeding habits is limited by lack of data. Here, we have developed a new tool to investigate their feeding ecology by combining the use of their predators as biological samplers together with measurements of the stable isotopic signature of their beaks. Cephalopod beaks are chitinous hard structures that resist digestion and the stable isotope ratios of carbon (δ
13
C) and nitrogen (δ
15
N) are indicators of the foraging areas and trophic levels of consumers, respectively. First, a comparison of δ
13
C and δ
15
N values of different tissues from the same individuals showed that beaks were slightly enriched in
13
C but highly impoverished in
15
N compared with lipid-free muscle tissues. Second, beaks from the same species showed a progressive increase in their δ
15
N values with increasing size, which is in agreement with a dietary shift from lower to higher trophic levels during cephalopod growth. In the same way, there was an increase in the δ
15
N signature of various parts of the same lower beaks in the order rostrum, lateral walls and wings, which reflects the progressive growth and chitinization of the beaks in parallel with dietary changes. Third, we investigated the trophic structure of a cephalopod community for the first time. Values of δ
15
N indicate that cephalopods living in slope waters of the subantarctic Kerguelen Islands (
n
=18 species) encompass almost three distinct trophic levels, with a continuum of two levels between crustacean- and fish-eaters and a distinct higher trophic level occupied by the colossal squid
Mesonychoteuthis hamiltoni
. δ
13
C values demonstrated that cephalopods grow in three different marine ecosystems, with 16 species living and developing in Kerguelen waters and two species migrating from either Antarctica (
Slosarczykovia circumantarctica
) or the subtropics (the giant squid
Architeuthis dux
). The stable isotopic signature of beaks accumulated in predators' stomachs therefore revealed new trophic relationships and migration patterns and is a powerful tool to investigate the role of the poorly known cephalopods in the marine environment.
Human locomotion on snow: determinants of economy and speed of skiing across the ages
Authors: Formenti Federico , Ardigò Luca P , Minetti Alberto E
Published: July 2005

We explore here the evolution of skiing locomotion in the last few thousand years by investigating how humans adapted to move effectively in lands where a cover of snow, for several months every year, prevented them from travelling as on dry ground. Following historical research, we identified the sets of skis corresponding to the ‘milestones’ of skiing evolution in terms of ingenuity and technology, built replicas of them and measured the metabolic energy associated to their use in a climate-controlled ski tunnel.

Six sets of skis were tested, covering a span from 542 AD to date. Our results show that: (i) the history of skiing is associated with a progressive decrease in the metabolic cost of transport, (ii) it is possible today to travel at twice the speed of ancient times using the same amount of metabolic power and (iii) the cost of transport is speed-independent for each ski model, as during running. By combining this finding with the relationship between time of exhaustion and the sustainable fraction of metabolic power, a prediction of the maximum skiing speed according to the distance travelled is provided for all past epochs, including two legendary historical journeys (1206 and 1520 AD) on snow. Our research shows that the performances in races originating from them (Birkebeiner and Vasaloppet) and those of other modern competitions (skating versus classical techniques) are well predicted by the evolution of skiing economy. Mechanical determinants of the measured progression in economy are also discussed in the paper.
Relatedness and helping in fish: examining the theoretical predictions
Authors: Stiver Kelly A , Dierkes Petra , Taborsky Michael , Lisle Gibbs H , Balshine Sigal
Published: July 2005

Many studies have attempted to explain the evolution of cooperation, yet little attention has been paid to what factors control the
amount
or
kind
of cooperation performed. Kin selection theory suggests that more cooperation, or
help
, should be given by relatives. However, recent theory suggests that under specific ecological and demographic conditions, unrelated individuals must ‘pay to stay’ in the group and therefore may help more. We tested these contrasting predictions using the cooperatively breeding fish,
Neolamprologus pulcher
, and found that the degree of work effort by helpers depended on which helping behaviours were considered and on their level of relatedness to the breeding male or female. In the field, helpers
unrelated
to the breeding male performed more territory defence, while helpers
unrelated
to the breeding female contributed less to territory defence. In the laboratory,
unrelated
group members helped more. Our work demonstrates that a number of factors in addition to kinship shape cooperative investment patterns.
Synergistic effects of combining morphological and molecular data in resolving the phylogeny of butterflies and skippers
Authors: Wahlberg Niklas , Braby Michael F , Brower Andrew V.Z , de Jong Rienk , Lee Ming-Min , Nylin Sören , Pierce Naomi E , Sperling Felix A.H , Vila Roger , Warren Andrew D , Zakharov Evgueni
Published: July 2005

Phylogenetic relationships among major clades of butterflies and skippers have long been controversial, with no general consensus even today. Such lack of resolution is a substantial impediment to using the otherwise well studied butterflies as a model group in biology. Here we report the results of a combined analysis of DNA sequences from three genes and a morphological data matrix for 57 taxa (3258 characters, 1290 parsimony informative) representing all major lineages from the three putative butterfly super-families (Hedyloidea, Hesperioidea and Papilionoidea), plus out-groups representing other ditrysian Lepidoptera families. Recently, the utility of morphological data as a source of phylogenetic evidence has been debated. We present the first well supported phylogenetic hypothesis for the butterflies and skippers based on a total-evidence analysis of both traditional morphological characters and new molecular characters from three gene regions (COI,EF-1αandwingless). All four data partitions show substantial hidden support for the deeper nodes, which emerges only in a combined analysis in which the addition of morphological data plays a crucial role. With the exception of Nymphalidae, the traditionally recognized families are found to be strongly supported monophyletic clades with the following relationships: (Hesperiidae+(Papilionidae+(Pieridae+(Nymphalidae+(Lycaenidae+Riodinidae))))). Nymphalidae is recovered as a monophyletic clade but this clade does not have strong support. Lycaenidae and Riodinidae are sister groups with strong support and we suggest that the latter be given family rank. The position of Pieridae as the sister taxon to nymphalids, lycaenids and riodinids is supported by morphology and theEF-1αdata but conflicted by theCOIandwinglessdata. Hedylidae are more likely to be related to butterflies and skippers than geometrid moths and appear to be the sister group to Papilionoidea+Hesperioidea.
Crossing species' range borders: interspecies gene exchange mediated by hybridogenesis
Authors: Schmeller Dirk S , Seitz Alfred , Crivelli Alain , Veith Michael
Published: July 2005

The distribution of species is limited by their ability to adapt to local environments. For adaptation by selection, genetic variability is crucial. As founder effects reduce genetic variability, extension of species' range borders is usually slow due to the reduced probability of successful colonization. However, the range limit might be extended by incorporating locally adapted genes. In western Palaearctic waterfrogs, interspecies hybrids show hemiclonal gametogenesis, are fertile and reproductively mimic one parental species. Genetic analysis, using allozyme loci, shows that they mediate gene exchange between the two parental species. Selection analysis provides evidence for local adaptation of single locus genotypes. This suggests that hybridogenesis presents a process which increases the number of neoform parental genotypes, exposing these to selection, and thereby revealing locally adapted genotypes which are essential for species range expansion.
Systematic Spatial Analysis of Gene Expression during Wheat Caryopsis Development
Authors: Drea Sinéad , Leader David J. , Arnold Ben C. , Shaw Peter , Dolan Liam , Doonan John H.
Published: July 2005

The cereal caryopsis is a complex tissue in which maternal and endosperm tissues follow distinct but coordinated developmental programs. Because of the hexaploid genome in wheat (Triticum aestivum), the identification of genes involved in key developmental processes by genetic approaches has been difficult. To bypass this limitation, we surveyed 888 genes that are expressed during caryopsis development using a novel high-throughput mRNA in situ hybridization method. This survey revealed novel distinct spatial expression patterns that either reflected the ontogeny of the developing caryopsis or indicated specialized cellular functions. We have identified both known and novel genes whose expression is cell cycle–dependent. We have identified the crease region as important in setting up the developmental patterning, because the transition from proliferation to differentiation spreads from this region to the rest of the endosperm. A comparison of this set of genes with the rice (Oryza sativa) genome shows that approximately two-thirds have rice counterparts but also suggests considerable divergence with regard to proteins involved in grain filling. We found that the wheat genes had significant homology with 350 Arabidopsis thaliana genes. At least 25 of these are already known to be essential for seed development in Arabidopsis, but many others remain to be characterized.
Quantitative model of cellulite: three‐dimensional skin surface topography, biophysical characterization, and relationship to human perception
Authors: Smalls L. K. , Lee C. Y. , Whitestone J. , Kitzmiller W. J. , Wickett R. R. , Visscher M. O.
Published: July 2005

Gynoid lipodystrophy (cellulite) is the irregular, dimpled skin surface of the thighs, abdomen, and buttocks in 85% of post‐adolescent women. The distinctive surface morphology is believed to result when subcutaneous adipose tissue protrudes into the lower reticular dermis, thereby creating irregularities at the surface. The biomechanical properties of epidermal and dermal tissue may also influence severity. Cellulite‐affected thigh sites were measured in 51 females with varying degrees of cellulite, in 11 non‐cellulite controls, and in 10 male controls. A non‐contact high‐resolution three‐dimensional (3D) laser surface scanner was used to quantify the skin surface morphology and determine specific roughness values. The scans were evaluated by experts and naїve judges (n = 62). Body composition was evaluated via dual‐energy X‐ray absorptiometry; dermal thickness and the dermal–subcutaneous junction were evaluated via high‐resolution 3D ultrasound and surface photography under compression. Biomechanical properties were also measured. The roughness parameters Svm (mean depth of the lowest valleys) and Sdr (ratio between the roughness surface area and the area of the xy plane) were highly correlated to the expert image grades and, therefore, designated as the quantitative measures of cellulite severity. The strength of the correlations among naїve grades, expert grades, and roughness values confirmed that the data quantitatively evaluate the human perception of cellulite. Cellulite severity was correlated to BMI, thigh circumference, percent thigh fat, architecture of the dermal–subcutaneous border (ultrasound surface area, red‐band SD from compressed images), compliance, and stiffness (negative correlation). Cellulite severity was predicted by the percent fat and the area of the dermal–subcutaneous border. The biomechanical properties did not significantly contribute to the prediction. Comparison of the parameters for females and males further suggests that percent thigh fat and surface area roughness deviation are the distinguishing features of cellulite.
Reaction characteristics of a tooth‐bleaching agent containing H2O2 and NaF: in vitro study of crystal structure change in treated hydroxyapatite and chemical states of incorporated fluorine
Authors: Tanizawa Y.
Published: July 2005

This in vitro study was performed to elucidate the reaction mechanism of sodium fluoride (NaF), which is added to tooth‐bleaching agents to lessen the adverse effect of hydrogen peroxide (H2O2) on teeth. Both hydroxyapatite (HAP) and dihydrated dicalcium phosphate (DCPD), model substances for dental hard tissues, dissolved easily in a simple H2O2 solution. In the H2O2/NaF solutions, however, fluorine compounds that could not be identified by X‐ray diffraction (XRD) due to the smallness of the products were formed on the surface of the HAP. X‐ray photoelectron spectroscopy (XPS) studies demonstrated that fluoridated hydroxyapatite (FHAP) was formed on HAP, and that calcium fluoride (CaF2) formation was accelerated by increasing the concentrations of fluorine and H2O2 along with the partial dissolution of HAP. In H2O2/NaF solution, DCPD also transformed easily to FHAP and CaF2, which are favorable to the remineralization process on the tooth surface. Thus, the mechanism of NaF was elucidated, and its use together with H2O2 for tooth bleaching was proved to be effective. Methodologically, the XPS two‐dimensional plot made it possible for the first time to directly estimate the ratio of FHAP and CaF2 in the reaction products, in contrast to the conventional wet‐analytical method, which is simply based on the difference in solubility of the two components.
Evaluation of antioxidant properties of dermocosmetic creams by direct electrochemical measurements
Authors: Guitton C. , Gros P. , Comtat M. , Tarroux R. , Bordat P.
Published: July 2005

Cyclic voltammetry and linear sweep voltammetry were preliminarily used in order to evaluate the global antioxidant properties of dermocosmetic creams. Experiments were performed by introducing electrodes directly into the creams without any pre‐treatment of the samples. Current potential curves showed significant anodic current depending on the antioxidant‐containing cream studied. In comparison, little amperometric response was recorded with an antioxidant‐free cream base. Aqueous solutions of the corresponding antioxidants showed analogous anodic waves and similar peak potentials. A correlation between the global anodic peak and the presence of the antioxidant species in the cream was made with eleven skin creams, attesting to the reliability of the method. Among the tested electrode materials, platinum gave the best results in terms of electrochemical kinetics and measurement precision (current peak standard deviation <5%). Exposure of a depilatory cream to oxidizing agents (e.g. hydrogen peroxide, air, or light) caused a decrease in peak current as expected. This methodology enabled us to evaluate the evolution of the total antioxidant capacity under oxidative stress and gives encouragement to further development of a voltammetric method to quantify cream antioxidant power.
Permeation study of five formulations of alpha‐tocopherol acetate through human cadaver skin
Authors: Mahamongkol H. , Bellantone R. A. , Stagni G. , Plakogiannis F. M.
Published: July 2005

Alpha‐tocopherol (AT) is the vitamin E homologue with the highest in vivo biological activity. Alpha‐tocopherol protects against the carcinogenic and mutagenic activity of ionizing radiation and chemical agents, and possibly against a UV‐induced cutaneous damage. For stability consideration, AT is usually used as its prodrug ester, alpha‐tocopherol acetate (ATA), which once absorbed into the skin is hydrolyzed to AT, the active form. The objective of this research was to characterize in vitro the permeation properties of ATA from various solutions and gel formulations. Permeation studies were conducted using modified Franz diffusion cells and human cadaver skin as the membrane. Specifically, 5% (w/w) ATA was formulated in the following vehicles: ethanol, isopropyl myristate, light mineral oil, 1% Klucel_ gel in ethanol, and 3% Klucel_ gel in ethanol (w/w). The receiver temperature was 37 °C. Samples from the receiver were collected at 2, 4, 6, 8, 12, 24, 30, 36, and 48 h and analysed by HPLC for concentrations of ATA and AT. The permeabilities of ATA through human cadaver skin were 1.0 × 10 – 4, 1.1 × 10 – 2, 1.4 × 10 – 4, 2.1 × 10 – 4, and 4.7 × 10 – 4 cm h–1 for the ethanol solution, isopropyl myristate solution, light mineral oil solution, 1% Klucel_ gel, and 3% Klucel_ gel, respectively. The results show that the formulation had relatively minor effects on the permeability coefficients of ATA through cadaver skin in all cases except for the isopropyl myristate solution.
Design Data for Engineering Ceramics: A Review of the Flexure Test
Authors: Quinn George D. , Morrell Roger
Published: July 2005

The uniaxial strength of engineering ceramics is often measured by the well‐known flexure strength test method there is a risk that flexure data are not representative of the properties of fabricated components. Reliability estimates for components based upon statistical extrapolation techniques from flexure data may not be valid. This paper reviews the problem and judges the usefulness of flexure data for design purposes. It is shown that some of the limitations of flexure data apply; to other modes of testing, including direct tension testing
Inhomogeneous Conductivity in Varistor Ceramics: Methods of Investigation
Authors: Hohenberger Gert , Tomandl Gerhard , Ebert Rolf , Taube Thomas
Published: July 2005

The grain boundaries in zinc oxide ceramics exhibit different electrical behaviors. This results in separate paths of current flux through the microstructure and also in different breakdown voltages of each path. The paper describes some new methods for characterization of these paths. A galvanic determination is able to show the number of paths and their distribution across the varistor surface. The differences in breakdown voltage are visible using a line scan method. Current images in SEM can detect the paths of current along a varistor surface. Possible reasons for inhomogeneous current flux are inhomogeneous distribution of dopants, insufficient binder burnout, and pressing faults.
High‐Temperature Phase Relations in the System Gd2O3‐Ta2O5
Authors: Yokogawa Yoshiyuki , Ishizawa Nobuo , Sōmiya Shigeyuki , Yoshimura Masahiro
Published: July 2005

The Phase relations of the system Gd2O3‐Ta2O5 in the composition range 50 to100 mol% Gd2O3 was studied by solidstate reactions at 1350°, 1500°, or 1700°C and by thermal analyses up to the melting temperatures. Weberite‐type orthorhombic phase (W2 phase, space group C2221) with the composition of Gd3 TaO7 seems to melt incongruently; at about 2040°C, although this Gd3TaO7 Phase was previously reported to melt congruently. A new fluorite‐type cubic phase (F phase, space group Fm3m) was found for the first time above 1500°C in the system. It melts congruently with the composition of about 80mol% Gd2O3at 2318° 3°C. A phase diagram was proposed for the system Gd2O3–Ta2O5 in the Gd2O3–rich portion
High‐Temperature Phase Relations in the System Y2O3‐Ta2O5
Authors: Yokogawa Yoshiyuki , Yoshimura Masahiro
Published: July 2005

The phase relations for the system y2o3–Ta2o5 in the composition range 50 to 100 mol% Y2O3 have been studied by solid‐state reactions at 1350°, 1500°, or 17000C and by thermal analyses up to the melting temperatures. Weberite‐type orthorhombic phases (W2 phase, space group C2221), fluorite‐type cubic phases (F phase, space group Fm3m)and another orthorhombic phase (O phase, space group Cmmm)are found in the system. The W2 phase forms in 75 mol% Y2O3 under 17000C and O phase in 70 mol% Y2O3 up to 1700°C These phases seem to melt incongruently. The F phase forms in about 80 mol% Y2O3 and melts congruently at 2454° 3°C. Two eutectic points seem to exist at about 2220°C 90 mol% Y2O3, and at about 1990°C, 62 mol% Y2O3. A Phase diagram including the above three phases were not identified with each other.
Impurity Distribution During Crystal Growth of Alite in Portland Cement Clinker
Authors: Maki Iwao , Fukuda Koichiro , Seki Shunichi , Tanioka Takashi
Published: July 2005

The concentration of foreign element (Al, Fe, Mg, and Ti) in alite in portland cement clinker decreases with increasing temparature of crystallization. The constituent phase of alite at ambient temperature changes systematically from M1 to M3 and then to T2 with decreasing concentration of Al and Fe in solid solution. The distribution of those amphoteric elements between the Ca‐ and Si‐sites in the structure of alite, depending on the concentration of CaO or SiO2 in the environmental liquid phase from which alite is precipitated, can be represented by the superposition of (Ca2Me)MeO5 and (Me2□)SiO5 (Me is Al, Fe and is a vacant Ca site).
Oxygen Tracer Diffusion in Single‐Crystal Alumina
Authors: Cawley James D. , Halloran John W. , Cooper Alfred R.
Published: July 2005

Oxygen tracer diffusion coefficients are determined in single‐crystal alumina samples; with differing dopant levels using the gas‐exchange technique. The diffusion direction is parallel to the c‐axis and the ambient Po2 is 1 atm (105 Pa) for all experiments except a single run with a low Po2 The diffusion is insensitive to both; impurities and ambient Po2 The insensitivities are discussed in terms of point‐defect clustering. Prior tracer studies are compared and discussed.
Kinetics of Formation of a Platelet‐Reinforced Ceramic Composite Prepared by the Directed Reaction of Zirconium with Boron Carbide
Authors: Johnson William B. , Nagelberg Alan S. , Breval Else
Published: July 2005

The kinetics of formation of a new class of ceramic composite material, zirconium diboride platelet‐reinforced zirconium carbides, are discussed. These materials are prepared by the directed reaction of molten zirconium with boron carbide to form a ceramic material composed of zirconium carbide matrix containing a controlled amount of residual zirconium metal. Results from interrupted growth studies, differential thermal analysis, adiabatic reaction temperature calculations, and kinetic measurements have been used to study the kinetics of the process. The reaction is very fast and proceeds parabolic ally with time with a rate constant between 1.6 X 10‐2 and 3.9 X 10‐2 cm2/s. The proposed mechanism suggests that when molten zirconium contacts boron carbide, the molten zirconium exothermically reacts with the boron carbide to form a boron‐rich liquid. Further reaction is sustained by the continuous dissolution of the boron carbide as the boron‐rich liquid is drawn into the boron carbide. The product is a zirconium carbiride/zirconium carbide/zirconium composite which homogenizes quickly at the reaction temperature to yield a uniform product microstructure throughout the composite. Two alternative rate‐limiting steps are discussed and the implications of each are explored.
Preparation of Superconducting Bi(Pb)‐Sr‐Ca‐Cu‐O Thick Films on Magnesia Substrate
Authors: Kim Duk Hee , Um Woo Sik , No Kwangsoo , Kim Ho Gi
Published: July 2005

Superconducting Bi(Pb)‐Sr‐Ca‐Cu‐O powders were prepared by the emulsion‐drying method The powders consisting of the low‐Tc phase (Bi(Pb)2Sr2Ca1Cu2Oy) and small amount of Ca2PbO4 were prepared by calcining under low oxygen partial pressure at 750°, 800°C. These calcined powders were used to prepare thick films on single‐crystal MgO(100) substrates using a screen‐printing technique to study the effect of the calcinations temperature and annealing procedure on the high‐Tc phase (Bi(Pb)2Sr2Ca2Cu3Oy)formation. The formation of high‐Tc phase was observed to be dependent on the calcinations conditions. The high‐Tc phase formed very quickly (sintering at 840°C for 4 h), and the best films showed a sharp superconducting transition at about 105 K.
Green Density of a Powder Compact and Its Influence on the Steady‐State Wave Velocity in Combustion Synthesis of Condensed Phase
Authors: Bhattacharya Arun K.
Published: July 2005

Various experimental evidence indicates that the porosity of a compact has a pronounced effect on the steady‐state velocity in combustion synthesis of condensed phases, hut no simple and explicit treatment for it is available in the literature. Utilizing an existing model of the effective thermal conductivity in a porous media, a simple model for the steady‐state velocity of the combustion front has been developed. As ob‐ served in experiments, the model also predicts a decrease in combustion velocity with increasing porosity. The developed equation can be helpful in the analysis and interpretation of experimental results in self‐propagating high‐temperature synthesis of condensed phase.