bluuebunny/crossref_metadata_2025 huggingface dataset:
On the size-dependent elasticity of silicon nanocantilevers: impact of defects
Authors: Sadeghian Hamed , Goosen Hans , Bossche Andre , Thijsse Barend , van Keulen Fred
Published: January 2011

Recent measurements have indicated that the elastic behaviour of silicon nanocantilevers and nanowires is size-dependent. Several theoretical models have been proposed to explain this phenomenon, mainly focused on surface stress effects. However, discrepancies are found between experiments and theories, indicating that there could be other influences in addition to surface effects. One of the important issues, which was experimentally confirmed and has not been considered, is accounting for the fact that experimentally tested nanocantilevers and nanowires are not defect free. In this paper molecular dynamics (MD) is utilized to study the effects of defects on the elasticity of silicon. The effective Young's modulus
of [1 0 0] and [1 1 0] oriented silicon nanoplates is extracted in the presence of defects, showing that such defects significantly influence the size-dependent behaviour in
. The MD results are compared with the results of continuum theory, showing that continuum theory holds, even for very small defects. Taking into account the surface effects, native oxide layers together with fabrication-induced defects, the experimental measurements can be explained. The studied example involved nanocantilevers, but can be extended to nanowires.
A review of micro-scale abrasion testing
Authors: Gant A J , Gee M G
Published: January 2011

Micro-scale abrasion (commonly referred to as ‘ball cratering’) is a small-scale tribological test method which can be operated on a desktop. It offers the possibility of providing a quick, cheap, localized abrasion test that can be used with small samples. In principle its operation is simple, but in practice there are issues with wear scar measurement, wear mode and its applicability to a wide variety of monolithic materials and coatings.
Varshni parameters for InAs/GaSb strained layer superlattice infrared photodetectors
Authors: Klein B , Plis E , Kutty M N , Gautam N , Albrecht A , Myers S , Krishna S
Published: January 2011

The temperature-dependent behaviour of the bandgap of mid- and long-wavelength as well as dual-colour (mid-/long-wavelength) infrared detectors based on InAs/GaSb strained layer superlattices (SLSs) with p-i-n and nBn designs has been investigated with temperature-dependent absorption, photoluminescence and spectral response techniques. Values of Varshni parameters, zero temperature bandgap E
0 and empirical coefficient α, were extracted and tabulated. The MWIR and LWIR superlattice detectors showed a temperature change of 0.325 meV K−1 and 0.282 meV K−1, respectively. These values are a factor of two lower than that of HgCdTe and InSb, making them attractive for higher operating temperatures.
Fabrication and mechanical properties of anodized zirconium dioxide nanotubular arrays
Authors: Wang Lu-Ning , Luo Jing-Li
Published: January 2011

A series of highly ordered ZrO2 nanotubular arrays with different thickness was synthesized by changing the anodization voltage or anodization period. The thickness of the nanotubular arrays depended on the anodization voltage and anodization period. Openings of the tubular structure were only slightly affected by the anodization voltage. Microindentation tests demonstrated that the apparent Young's modulus, ratio of elastic energy to the total deformation energy and hardness decreased as the thickness of the nanotubular array films increased due to densification and collapse of longer nanotubes under external force. Resistance of nanotubular arrays to sliding wear was evaluated in different cultures. Wear loss, which was proportional to the width of the wear track, significantly decreased in water compared with that in air. The pH values of solutions slightly affected the width of the wear track of the ZrO2 nanotubular arrays. The results showed that wear loss of the ZrO2 nanotubular arrays and friction force on the ZrO2 nanotubular arrays decreased with increasing pH from 2.5 to 13.
Lithium surface-response modelling for the NSTX liquid lithium divertor
Authors: Allain J.P. , Brooks J.N.
Published: January 2011

We analyse lithium sputtering, evaporation and transport for the National Spherical Torus Experiment (NSTX) liquid lithium divertor (LLD) for planned high heating power plasma conditions. A temperature-dependent, data-calibrated, surface-response model is used to specify sputter yield, velocity distributions, sputtered Li ion fraction and related phenomena, for the static liquid lithium surface with D, Li and trace C impingement. Using the surface-response model, and supplied UEDGE code edge plasma parameters and LLD surface temperature profile for a typical 2 MW heating, low D-recycle shot, the REDEP/WBC code package computes Li erosion/redeposition. The results are encouraging showing negligible Li evaporation, moderate sputter erosion, and acceptable Li transport to the edge (∼7% Li/D density) and core plasma (∼1% Li/D contamination potential) and LLD adjacent surfaces. A 2% carbon plasma content does not significantly affect the LLD surface response. For fixed plasma conditions, but with hypothetically higher surface temperatures than the reference 281 °C peak, an increase to ∼350 °C appears acceptable, thus implying a significant operating temperature margin.
Error field correction in DIII-D Ohmic plasmas with either handedness
Authors: Park Jong-Kyu , Schaffer Michael J. , La Haye Robert J. , Scoville Timothy J. , Menard Jonathan E.
Published: January 2011

Error field correction results in DIII-D plasmas are presented in various configurations. In both left-handed and right-handed plasma configurations, where the intrinsic error fields become different due to the opposite helical twist (handedness) of the magnetic field, the optimal error correction currents and the toroidal phases of internal(I)-coils are empirically established. Applications of the Ideal Perturbed Equilibrium Code to these results demonstrate that the field component to be minimized is not the resonant component of the external field, but the total field including ideal plasma responses. Consistency between experiment and theory has been greatly improved along with the understanding of ideal plasma responses, but non-ideal plasma responses still need to be understood to achieve the reliable predictability in tokamak error field correction.
Polymer materials with spatially graded morphologies: preparation, characterization and utilization
Authors: Fujiki Daisuke , Jing Chuanming , Van-Pham Dan-Thuy , Nakanishi Hideyuki , Norisuye Tomohisa , Tran-Cong-Miyata Qui
Published: January 2011

Experimental studies on polymer materials with spatially graded structures are reviewed in this paper. A wide variety of principles and experimental methods utilized to prepare and control these specific structures of polymer materials are summarized and discussed. In particular, the method of using light to generate and control these gradient morphologies in the micrometer scales is summarized with great detail for binary polymer mixtures. Finally, recent studies on copolymers with various gradient compositions at nanometer length scales are also summarized in this review.
Bounding the support of a measure from its marginal moments
Authors: Lasserre Jean
Published: January 2011

Given all moments of the marginals of a measure

μ
\mu

on

R

n

\mathbb {R}^n

, one provides (a) explicit bounds on its support and (b) a numerical scheme to compute the smallest box that contains the support of

μ
\mu

.
On adapted coordinate systems
Authors: Ikromov Isroil , Müller Detlef
Published: January 2011

The notion of an adapted coordinate system for a given real-analytic function, introduced by V. I. Arnol’d, plays an important role, for instance, in the study of asymptotic expansions of oscillatory integrals. In two dimensions, A. N. Varchenko gave sufficient conditions for the adaptness of a given coordinate system and proved the existence of an adapted coordinate system for analytic functions without multiple components. Varchenko’s proof is based on a two-dimensional resolution of singularities result.

In this article, we present a more elementary approach to these results, which is based on the Puiseux series expansion of roots of the given function. This approach is inspired by the work of D. H. Phong and E. M. Stein on the Newton polyhedron and oscillatory integral operators. It applies to arbitrary real-analytic functions, and even to arbitrary smooth functions of finite type. In particular, we show that Varchenko’s conditions are in fact necessary and sufficient for the adaptedness of a given coordinate system and that adapted coordinates always exist in two dimensions, even in the smooth, finite type setting. For analytic functions, a construction of adapted coordinates by means of Puiseux series expansions of roots has already been carried out in work by D. H. Phong, E. M. Stein and J. A. Sturm on the growth and stability of real-analytic function, as we learned after the completion of this paper. In contrast to their work, however, our proof more closely follows Varchenko’s algorithm for the construction of an adapted coordinate system, which turns out to be useful for the extension to the smooth setting.
Identity-by-descent filtering of exome sequence data for disease–gene identification in autosomal recessive disorders
Authors: Rödelsperger Christian , Krawitz Peter , Bauer Sebastian , Hecht Jochen , Bigham Abigail W. , Bamshad Michael , de Condor Birgit Jonske , Schweiger Michal R. , Robinson Peter N.
Published: January 2011

Motivation: Next-generation sequencing and exome-capture technologies are currently revolutionizing the way geneticists screen for disease-causing mutations in rare Mendelian disorders. However, the identification of causal mutations is challenging due to the sheer number of variants that are identified in individual exomes. Although databases such as dbSNP or HapMap can be used to reduce the plethora of candidate genes by filtering out common variants, the remaining set of genes still remains on the order of dozens.

Results: Our algorithm uses a non-homogeneous hidden Markov model that employs local recombination rates to identify chromosomal regions that are identical by descent (IBD = 2) in children of consanguineous or non-consanguineous parents solely based on genotype data of siblings derived from high-throughput sequencing platforms. Using simulated and real exome sequence data, we show that our algorithm is able to reduce the search space for the causative disease gene to a fifth or a tenth of the entire exome.

Availability: An R script and an accompanying tutorial are available at http://compbio.charite.de/index.php/ibd2.html.

Contact:  peter.robinson@charite.de
Quality control and preprocessing of metagenomic datasets
Authors: Schmieder Robert , Edwards Robert
Published: January 2011

Summary: Here, we present PRINSEQ for easy and rapid quality control and data preprocessing of genomic and metagenomic datasets. Summary statistics of FASTA (and QUAL) or FASTQ files are generated in tabular and graphical form and sequences can be filtered, reformatted and trimmed by a variety of options to improve downstream analysis.

Availability and Implementation: This open-source application was implemented in Perl and can be used as a stand alone version or accessed online through a user-friendly web interface. The source code, user help and additional information are available at http://prinseq.sourceforge.net/.

Contact:  rschmied@sciences.sdsu.edu; redwards@cs.sdsu.edu
Business Attitudes Toward Statistical
Investigation in Late Nineteenth Century Italy: A
Wool Industrialist from Reticence to
Influence
Authors: Favero Giovanni
Published: January 2011

Statistical representations are usually
the result of negotiations and conventions with
regard to what should be counted, and how it
should be counted. A wide literature has shown
that this has been the case for almost any kind of
statistical data collected in the last few
centuries, from censuses to demographic, social,
and economic surveys and time series.
The evolution of island gigantism and body size variation in tortoises and turtles
Authors: Jaffe Alexander L. , Slater Graham J. , Alfaro Michael E.
Published: January 2011

Extant chelonians (turtles and tortoises) span almost four orders of magnitude of body size, including the startling examples of gigantism seen in the tortoises of the Galapagos and Seychelles islands. However, the evolutionary determinants of size diversity in chelonians are poorly understood. We present a comparative analysis of body size evolution in turtles and tortoises within a phylogenetic framework. Our results reveal a pronounced relationship between habitat and optimal body size in chelonians. We found strong evidence for separate, larger optimal body sizes for sea turtles and island tortoises, the latter showing support for the rule of island gigantism in non-mammalian amniotes. Optimal sizes for freshwater and mainland terrestrial turtles are similar and smaller, although the range of body size variation in these forms is qualitatively greater. The greater number of potential niches in freshwater and terrestrial environments may mean that body size relationships are more complicated in these habitats.
Chronic exposure to dim light at night suppresses immune responses in Siberian hamsters
Authors: Bedrosian Tracy A. , Fonken Laura K. , Walton James C. , Nelson Randy J.
Published: January 2011

Species have been adapted to specific niches optimizing survival and reproduction; however, urbanization by humans has dramatically altered natural habitats. Artificial light at night (LAN), termed ‘light pollution’, is an often overlooked, yet increasing disruptor of habitats, which perturbs physiological processes that rely on precise light information. For example, LAN alters the timing of reproduction and activity in some species, which decreases the odds of successful breeding and increases the threat of predation for these individuals, leading to reduced fitness. LAN also suppresses immune function, an important proxy for survival. To investigate the impact of LAN in a species naive to light pollution in its native habitat, immune function was examined in Siberian hamsters derived from wild-caught stock. After four weeks exposure to dim LAN, immune responses to three different challenges were assessed: (i) delayed-type hypersensitivity (DTH), (ii) lipopolysaccharide-induced fever, and (iii) bactericide activity of blood. LAN suppressed DTH response and reduced bactericide activity of blood after lipopolysaccharide treatment, in addition to altering daily patterns of locomotor activity, suggesting that human encroachment on habitats via night-time lighting may inadvertently compromise immune function and ultimately fitness.
Sex differences in spatial ability: a test of the range size hypothesis in the order Carnivora
Authors: Perdue Bonnie M. , Snyder Rebecca J. , Zhihe Zhang , Marr M. Jackson , Maple Terry L.
Published: January 2011

Sex differences in spatial cognition have been reported for many species ranging from voles to humans. The
range size hypothesis
predicts that sex differences in spatial ability will only occur in species in which the mating system selects for differential range size. Consistent with this prediction, we observed sex differences in spatial ability in giant pandas, a promiscuous species in which males inhabit larger ranges than females, but did not observe sex differences in Asian small-clawed otters, a related monogamous species in which males and females share home ranges. These results provide the first evidence of sex differences in spatial ability in the order Carnivora, and are consistent with the range size hypothesis.
Does reduced heterozygosity influence dispersal? A test using spatially structured populations in an alpine ungulate
Authors: Shafer Aaron B. A. , Poissant Jocelyn , Côté Steeve D. , Coltman David W.
Published: January 2011

Despite having a profound effect on population dynamics, the reasons that animals disperse are poorly understood. Evolutionary explanations have focused on inbreeding and competition, where the potential cost of philopatry is negated through dispersal. Such scenarios lead to the prediction that less successful individuals preferentially disperse, termed ‘fitness-associated dispersal’. Since heterozygosity is associated with fitness, we assessed whether dispersed animals had less observed heterozygosity (HO) than residents. We tested this prediction using both genetic and population-monitoring data of mountain goats (Oreamnos americanus). Individuals classified as dispersers through cross-assignment had the lowest meanHO, followed by residents, and then admixed individuals. Dispersed individuals had 6.3 per cent lessHOthan their subpopulation of origin. In the long-term study of the mountain goat herd at Caw Ridge, Alberta, immigrants had the lowestHO; however, the opposite pattern was seen in emigrants, which may be related to density dependence. This study is the first to provide empirical evidence that heterozygosity is associated with dispersal.
A novel resource–service mutualism between bats and pitcher plants
Authors: Grafe T. Ulmar , Schöner Caroline R. , Kerth Gerald , Junaidi Anissa , Schöner Michael G.
Published: January 2011

Mutualistic relationships between vertebrates and plants apart from the pollen and seed-dispersal syndromes are rare. At first view, carnivorous pitcher plants of the genus
Nepenthes
seem to be highly unlikely candidates for mutualistic interactions with animals, as they form dimorphic terrestrial and aerial pitchers that trap arthropods and small vertebrates. Surprisingly, however, the aerial pitchers of
Nepenthes rafflesiana
variety
elongata
are poor insect traps, with low amounts of insect-attractive volatile compounds and low amounts of digestive fluid. Here, we show that
N. rafflesiana elongata
gains an estimated 33.8 per cent of the total foliar nitrogen from the faeces of Hardwicke's woolly bats (
Kerivoula hardwickii hardwickii
) that exclusively roost in its aerial pitchers. This is the first case in which the faeces-trapping syndrome has been documented in a pitcher plant that attracts bats and only the second case of a mutualistic association between a carnivorous plant and a mammal to date.
Spatial facilitation by a high-performance dragonfly target-detecting neuron
Authors: Nordström Karin , Bolzon Douglas M. , O'Carroll David C.
Published: January 2011

Many animals visualize and track small moving targets at long distances—be they prey, approaching predators or conspecifics. Insects are an excellent model system for investigating the neural mechanisms that have evolved for this challenging task. Specialized small target motion detector (STMD) neurons in the optic lobes of the insect brain respond strongly even when the target size is below the resolution limit of the eye. Many STMDs also respond robustly to small targets against complex stationary or moving backgrounds. We hypothesized that this requires a complex mechanism to avoid breakthrough responses by background features, and yet to adequately amplify the weak signal of tiny targets. We compared responses of dragonfly STMD neurons to small targets that begin moving within the receptive field with responses to targets that approach the same location along longer trajectories. We find that responses along longer trajectories are strongly facilitated by a mechanism that builds up slowly over several hundred milliseconds. This allows the neurons to give sustained responses to continuous target motion, thus providing a possible explanation for their extraordinary sensitivity.
Failure to fix nitrogen by non-reproductive symbiotic rhizobia triggers host sanctions that reduce fitness of their reproductive clonemates
Authors: Oono Ryoko , Anderson Carolyn G. , Denison R. Ford
Published: January 2011

The legume–rhizobia symbiosis is a classical mutualism where fixed carbon and nitrogen are exchanged between the species. Nonetheless, the plant carbon that fuels nitrogen (N
2
) fixation could be diverted to rhizobial reproduction by ‘cheaters’—rhizobial strains that fix less N
2
but potentially gain the benefit of fixation by other rhizobia. Host sanctions can decrease the relative fitness of less-beneficial reproductive bacteroids and prevent cheaters from breaking down the mutualism. However, in certain legume species, only undifferentiated rhizobia reproduce, while only terminally differentiated rhizobial bacteroids fix nitrogen. Sanctions were, therefore, tested in two legume species that host non-reproductive bacteroids. We demonstrate that even legume species that host non-reproductive bacteroids, specifically pea and alfalfa, can severely sanction undifferentiated rhizobia when bacteroids within the same nodule fail to fix N
2
. Hence, host sanctions by a diverse set of legumes play a role in maintaining N
2
fixation.
Fluorescence of coral larvae predicts their settlement response to crustose coralline algae and reflects stress
Authors: Kenkel C. D. , Traylor M. R. , Wiedenmann J. , Salih A. , Matz M. V.
Published: January 2011

Multi-coloured homologues of the green fluorescent protein generate some of the most striking visual phenomena in the ocean. Despite their natural prominence in reef-building corals and widespread use in biotechnology, their biological role remains obscure. Here, we experimented with larvae of
Acropora millepora
to determine what can be learned about a coral larva or recruit from its fluorescent colour. We performed 12 crosses between seven
A. millepora
colonies representing differing fluorescence phenotypes, the larvae of which were exposed to a natural settlement cue (crustose coralline algae) and heat–light stress. Parental effects explained 18 per cent of variation in colour and 47 per cent of variation in settlement. The colour of the larval family emerged as a predictor of the settlement success: redder families were significantly less responsive to the provided settlement cue (
p
= 0.006). This relationship was owing to a correlation between parental effects on settlement and colour (
r
2
= 0.587,
p
= 0.045). We also observed pronounced (16%) decline in settlement rate, as well as subtle (2%), but a statistically significant decrease in red fluorescence, as a consequence of heat–light stress exposure. Variation in settlement propensity in
A. millepora
is largely owing to additive genetic effects, and is thought to reflect variation in dispersal potential. Our results suggest an optical signature to discriminate between long- and short-range dispersing genotypes, as well as to evaluate stress. Further research in this direction may lead to the development of field applications to trace changes in coral life history and physiology caused by global warming.
The relationship between pink salmon biomass and the body condition of short-tailed shearwaters in the Bering Sea: can fish compete with seabirds?
Authors: Toge Kanako , Yamashita Rei , Kazama Kentaro , Fukuwaka Masaaki , Yamamura Orio , Watanuki Yutaka
Published: January 2011

Seabirds and large fishes are important top predators in marine ecosystems, but few studies have explored the potential for competition between these groups. This study investigates the relationship between an observed biennial change of pink salmon (
Oncorhynchus gorbuscha
) biomass in the central Bering Sea (23 times greater in odd-numbered than in even-numbered years) and the body condition and diet of the short-tailed shearwater (
Puffinus tenuirostris
) that spends the post-breeding season there. Samples were collected with research gill nets over seven summers. Both species feed on krill, small fishes and squid. Although the mean pink salmon catch per unit effort (in mass) over the study region was not related significantly with shearwater's stomach content mass or prey composition, the pink salmon biomass showed a negative and significant relationship with the shearwater's body mass and liver mass (proxies of energy reserve). We interpret these results as evidence that fishes can negatively affect mean prey intake of seabirds if they feed on a shared prey in the pelagic ecosystem.
Intuitive physical reasoning about occluded objects by inexperienced chicks
Authors: Chiandetti Cinzia , Vallortigara Giorgio
Published: January 2011

Questions concerning the role of nature and nurture in higher cognition appear to be intractable if one restricts one's attention to development in humans. However, in other domains, such as sensory development, much information has been gained from controlled rearing studies with animals. Here, we used a similar experimental strategy to investigate intuitive reasoning about occluded objects. Newborn domestic chicks (Gallus gallus) were reared singly with a small object that became their social partner. They were then accustomed to rejoin such an imprinting object when it was made to move and disappear behind either one of two identical opaque screens. After disappearance of the imprinting object, chicks were faced with two screens of different slants, or of different height or different width, which may or may not have been compatible with the presence of the imprinting object hidden beneath/behind them. Chicks consistently chose the screen of slant/height/width compatible with the presence of the object beneath/behind it. Preventing chicks from touching and pecking at the imprinting object before testing did not affect the results, suggesting that intuitive reasoning about physical objects is largely independent of specific experience of interaction with objects and of objects' occluding events.
Intraspecific evidence from guppies for correlated patterns of male and female genital trait diversification
Authors: Evans Jonathan P. , Gasparini Clelia , Holwell Gregory I. , Ramnarine Indar W. , Pitcher Trevor E. , Pilastro Andrea
Published: January 2011

The role of sexual selection in fuelling genital evolution is becoming increasingly apparent from comparative studies revealing interspecific divergence in male genitalia and evolutionary associations between male and female genital traits. Despite this, we know little about intraspecific variance in male genital morphology, or how male and female reproductive traits covary among divergent populations. Here we address both topics using natural populations of the guppy,
Poecilia reticulata
, a livebearing fish that exhibits divergent patterns of male sexual behaviour among populations. Initially, we performed a series of mating trials on a single population to examine the relationship between the morphology of the male's copulatory organ (the gonopodium) and the success of forced matings. Using a combination of linear measurements and geometric morphometrics, we found that variation in the length and shape of the gonopodium predicted the success of forced matings in terms of the rate of genital contacts and insemination success, respectively. We then looked for geographical divergence in these traits, since the relative frequency of forced matings tends to be greater in high-predation populations. We found consistent patterns of variation in male genital size and shape in relation to the level of predation, and corresponding patterns of (co)variation in female genital morphology. Together, these data enable us to draw tentative conclusions about the underlying selective pressures causing correlated patterns of divergence in male and female genital traits, which point to a role for sexually antagonistic selection.
Sense and sensitivity: responsiveness to offspring signals varies with the parents' potential to breed again
Authors: Thorogood Rose , Ewen John G. , Kilner Rebecca M.
Published: January 2011

How sensitive should parents be to the demands of their young? Offspring are under selection to seek more investment than is optimal for parents to supply, which makes parents vulnerable to losing future fitness by responding to manipulative displays. Yet, parents cannot afford to ignore begging and risk allocating resources inefficiently. Here, we show that parents may solve this problem by adjusting their sensitivity to begging behaviour in relation to their own likelihood of breeding again, a factor largely neglected in previous analyses of parent–offspring interactions. In two carotenoid-supplementation experiments on a New Zealand passerine, the hihiNotiomystis cincta, we supplemented adults to enhance their propensity to breed again, and supplemented entire broods to increase their mouth colour, thus enhancing their solicitation display. We found that adults that attempted two breeding attempts a season were largely insensitive to the experimentally carotenoid-rich gapes of their brood, whereas those that bred just once responded by increasing their rate of provisioning at the nest. Our results show that parents can strategically vary their sensitivity to begging in relation to their future reproductive potential. By restricting opportunities for offspring to influence provisioning decisions, parents greatly limit the potential for offspring to win parent–offspring conflict.
Intercontinental dispersal by a microendemic burrowing reptile (Dibamidae)
Authors: Townsend Ted M. , Leavitt Dean H. , Reeder Tod W.
Published: January 2011

Intercontinental dispersal via land bridge connections has been important in the biogeographic history of many Holarctic plant and animal groups. Likewise, some groups appear to have accomplished trans-oceanic dispersal via rafting. Dibamid lizards are a clade of poorly known fossorial, essentially limbless species traditionally split into two geographically disjunct genera:Dibamuscomprises approximately 20 Southeast Asian species, many of which have very limited geographical distributions, and the monotypic genusAnelytropsisoccupies a small area of northeastern Mexico. Although no formal phylogeny of the group exists, a sister–taxon relationship between the two genera has been assumed based on biogeographic considerations. We used DNA sequence data from one mitochondrial and six nuclear protein-coding genes to construct a phylogeny of Dibamidae and to estimate divergence times within the group. Surprisingly, sampledDibamusspecies form two deeply divergent, morphologically conserved and geographically concordant clades, one of which is the sister taxon ofAnelytropsis papillosus. Our analyses indicate Palaearctic to Nearctic Beringian dispersal in the Late Palaeocene to Eocene. Alternatively, a trans-Pacific rafting scenario would extend the upper limit on dispersal to the Late Cretaceous. Either scenario constitutes a remarkable long-distance dispersal in what would seem an unlikely candidate.
Evidence for subpopulations of Listeria monocytogenes with enhanced invasion of cardiac cells
Authors: Alonzo Francis , Bobo Linda D. , Skiest Daniel J. , Freitag Nancy E.
Published: January 2011

Cardiac infections caused by the foodborne bacteriumListeria monocytogenesrepresent a significant but poorly studied facet of disease. It is not known whetherL. monocytogenescardiac infections stem solely from host susceptibility, or whether bacterial isolates exist that exhibit a tropism for cardiac tissue. Here we examine the cardio-invasive capacity of a recentL. monocytogenescardiac case strain (07PF0776) as well as nine additional outbreak and clinical isolates. Mice infected with the cardiac isolate 07PF0776 had 10-fold more bacteria recovered from heart tissue than those infected withL. monocytogenesstrain 10403S, a well-characterized clinical isolate originally obtained from a human skin lesion. AdditionalL. monocytogenesisolates exhibited varied capacities to colonize the hearts of mice; however, those with the highest efficiency of mouse cardiac invasion also demonstrated the highest levels of bacterial invasion in cultured myoblast cells. Our findings strongly suggest that subpopulations ofL. monocytogenesstrains have acquired an enhanced ability to target and invade the myocardium.
Target of Rapamycin Regulates Development and Ribosomal RNA Expression through Kinase Domain in Arabidopsis
Authors: Ren Maozhi , Qiu Shuqing , Venglat Prakash , Xiang Daoquan , Feng Li , Selvaraj Gopalan , Datla Raju
Published: January 2011

Target of rapamycin (TOR) is a central regulator of cell growth, cell death, nutrition, starvation, hormone, and stress responses in diverse eukaryotes. However, very little is known about TOR signaling and the associated functional domains in plants. We have taken a genetic approach to dissect TOR functions in Arabidopsis (Arabidopsis thaliana) and report here that the kinase domain is essential for the role of TOR in embryogenesis and 45S rRNA expression. Twelve new T-DNA insertion mutants, spanning 14.2 kb of TOR-encoding genomic region, have been characterized. Nine of these share expression of defective kinase domain and embryo arrest at 16 to 32 cell stage. However, three T-DNA insertion lines affecting FATC domain displayed normal embryo development, indicating that FATC domain was dispensable in Arabidopsis. Genetic complementation showed that the TOR kinase domain alone in tor-10/tor-10 mutant background can rescue early embryo lethality and restore normal development. Overexpression of full-length TOR or kinase domain in Arabidopsis displayed developmental abnormalities in meristem, leaf, root, stem, flowering time, and senescence. We further show that TOR, especially the kinase domain, plays a role in ribosome biogenesis by activating 45S rRNA production. Of the six putative nuclear localization sequences in the kinase domain, nuclear localization sequence 6 was identified to confer TOR nuclear targeting in transient expression assays. Chromatin immunoprecipitation studies revealed that the HEAT repeat domain binds to 45S rRNA promoter and the 5′ external transcribed spacer elements motif. Together, these results show that TOR controls the embryogenesis, postembryonic development, and 45S rRNA production through its kinase domain in Arabidopsis.
Excision and Episomal Replication of Cauliflower mosaic virus Integrated into a Plant Genome
Authors: Squires Julie , Gillespie Trudi , Schoelz James E. , Palukaitis Peter
Published: January 2011

Transgenic Arabidopsis (Arabidopsis thaliana) plants containing a monomeric copy of the cauliflower mosaic virus (CaMV) genome exhibited the generation of infectious, episomally replicating virus. The circular viral genome had been split within the nonessential gene II for integration into the Arabidopsis genome by Agrobacterium tumefaciens-mediated transformation. Transgenic plants were assessed for episomal infections at flowering, seed set, and/or senescence. The infections were confirmed by western blot for the CaMV P6 and P4 proteins, electron microscopy for the presence of icosahedral virions, and through polymerase chain reaction across the recombination junction. By the end of the test period, a majority of the transgenic Arabidopsis plants had developed episomal infections. The episomal form of the virus was infectious to nontransgenic plants, indicating that no essential functions were lost after release from the Arabidopsis chromosome. An analysis of the viral genomes recovered from either transgenic Arabidopsis or nontransgenic turnip (Brassica rapa var rapa) revealed that the viruses contained deletions within gene II, and in some cases, the deletions extended to the beginning of gene III. In addition, many of the progeny viruses contained small regions of nonviral sequence derived from the flanking transformation vector. The nature of the nucleotide sequences at the recombination junctions in the circular progeny virus indicated that most were generated by nonhomologous recombination during the excision event. The release of the CaMV viral genomes from an integrated copy was not dependent upon the application of environmental stresses but occurred with greater frequency with either age or the late stages of plant maturation.
Two Distinct Roles of ARABIDOPSIS HOMOLOG OF TRITHORAX1 (ATX1) at Promoters and within Transcribed Regions of ATX1-Regulated Genes
Authors: Ding Yong , Avramova Zoya , Fromm Michael
Published: January 2011

The Arabidopsis thaliana trithorax-like protein, ATX1, shares common structural domains, has similar histone methyltransferase (HMT) activity, and belongs in the same phylogenetic subgroup as its animal counterparts. Most of our knowledge of the role of HMTs in trimethylating lysine 4 of histone H3 (H3K4me3) in transcriptional regulation comes from studies of yeast and mammalian homologs. Little is known about the mechanism by which ATX1, or any other HMT of plant origin, affects transcription. Here, we provide insights into how ATX1 influences transcription at regulated genes, playing two distinct roles. At promoters, ATX1 is required for TATA binding protein (TBP) and RNA Polymerase II (Pol II) recruitment. In a subsequent event, ATX1 is recruited by a phosphorylated form of Pol II to the +300-bp region of transcribed sequences, where it trimethylates nucleosomes. In support of this model, inhibition of phosphorylation of the C-terminal domain of Pol II reduced the amounts of H3K4me3 and ATX1 bound at the +300-nucleotide region. Importantly, these changes did not reduce the occupancy of ATX1, TBP, or Pol II at promoters. Our results indicate that ATX1 affects transcription at target genes by a mechanism distinct from its ability to trimethylate H3K4 within genes.
Regulation and Flexibility of Genomic Imprinting during Seed Development
Authors: Raissig Michael T. , Baroux Célia , Grossniklaus Ueli
Published: January 2011

Genomic imprinting results in monoallelic gene expression in a parent-of-origin–dependent manner. It is achieved by the differential epigenetic marking of parental alleles. Over the past decade, studies in the model systems Arabidopsis thaliana and maize (Zea mays) have shown a strong correlation between silent or active states with epigenetic marks, such as DNA methylation and histone modifications, but the nature of the primary imprint has not been clearly established for all imprinted genes. Phenotypes and expression patterns of imprinted genes have fueled the perception that genomic imprinting is specific to the endosperm, a seed tissue that does not contribute to the next generation. However, several lines of evidence suggest a potential role for imprinting in the embryo, raising questions as to how imprints are erased and reset from one generation to the next. Imprinting regulation in flowering plants shows striking similarities, but also some important differences, compared with the mechanisms of imprinting described in mammals. For example, some imprinted genes are involved in seed growth and viability in plants, which is similar in mammals, where imprinted gene regulation is essential for embryonic development. However, it seems to be more flexible in plants, as imprinting requirements can be bypassed to allow the development of clonal offspring in apomicts.
Assembly of the Chloroplast ATP-Dependent Clp Protease in Arabidopsis Is Regulated by the ClpT Accessory Proteins
Authors: Sjögren Lars L.E. , Clarke Adrian K.
Published: January 2011

The ATP-dependent caseinolytic protease (Clp) is an essential housekeeping enzyme in plant chloroplasts. It is by far the most complex of all known Clp proteases, with a proteolytic core consisting of multiple catalytic ClpP and noncatalytic ClpR subunits. It also includes a unique form of Clp protein of unknown function designated ClpT, two of which exist in the model species Arabidopsis thaliana. Inactivation of ClpT1 or ClpT2 significantly reduces the amount of Clp proteolytic core, whereas loss of both proves seedling lethal under autotrophic conditions. During assembly of the Clp proteolytic core, ClpT1 first binds to the P-ring (consisting of ClpP3-6 subunits) followed by ClpT2, and only then does the P-ring combine with the R-ring (ClpP1, ClpR1-4 subunits). Most of the ClpT proteins in chloroplasts exist in vivo as homodimers, which then apparently monomerize prior to association with the P-ring. Despite their relative abundance, however, the availability of both ClpT proteins is rate limiting for the core assembly, with the addition of recombinant ClpT1 and ClpT2 increasing core content up to fourfold. Overall, ClpT appears to regulate the assembly of the chloroplast Clp protease, revealing a new and sophisticated control mechanism on the activity of this vital protease in plants.
Physico‐chemical properties of African star apple (Chrysophylum albidum) components
Authors: Adunni Abiodun Olufunmilola , Oladapo A.S.
Published: January 2011

Purpose

The purpose of this paper is to evaluate the physico‐chemical properties of African star apple (Chrysophylum albidum) components. African star apples are among the under‐utilized fruits in Nigeria therefore, the four succulent components (peel, pulp, juice and pericarp) of the fruit were analyzed and compared with other known fruits.

Design/methodology/approach

African star apples were purchased and divided into two portions. The first portion was washed and the juice was expressed manually into a bottle and covered, while in the second portion, the peel, pulp and the pericarp (mucilage on the seeds) were separated. The physico‐chemical analyses (moisture, total solid, pH, titratable acidity, total sugar, carotenoids, ascorbic acid and total soluble solids) were carried out on the four components.

Findings

Moisture content ranged from 53.5 per cent in peel to 86.3 per cent in juice, while the peel had higher total solid and the least was in the juice. The pH of peel was lower than that of other components. The peel had lower titratable acidity (1.2 per cent) and sugar (0.9 Brix) while the juice had higher value (5.4 Brix) in sugar and 15.0 mg/100 g carotenoid. The juice was rich in ascorbic acid (28.5 mg/100 g) followed by the pulp (25.0 mg/100 g). The pulp had higher total soluble solids (24.8 per cent) and the least was in the pericarp (9.8 per cent).

Originality/value

The physico‐chemical properties of the African star apple fruit gave an indication of the usefulness of this fruit in brewing industry especially for wine making and jelly or jam manufacture. Processing of this fruit will curb wastage during its season and make it available in different form.
Diet adequacy in UK schoolchildren
Authors: Ruxton C.H.S. , Derbyshire E.
Published: January 2011

Purpose

There is a strong interest in the quality of children's diets as this can impact on current and future health. The aim of this paper is to review current and past literature on UK children's diets to evaluate the adequacy of nutrient intakes in comparison with recommendations, and to identify population groups that may be at particular risk of nutritional deficiencies.

Design/methodology/approach

A literature review was carried out to locate and summarise up‐to‐date published studies and reports which addressed dietary intakes of UK children, trends overtime and current dietary issues.

Findings

Although UK children's diets appear to have improved in recent years, intakes of several key nutrients remain below dietary recommendations. Iron, calcium, magnesium, potassium and zinc are especially low in some groups, whilst intakes of saturated fat and sugar exceed current targets. Thus, further improvements are needed. In the meantime, parents may consider giving children a daily multi‐vitamin to ensure that micronutrient recommendations are achieved. The lack of child‐specific targets for fibre, long‐chain omega‐3 polyunsaturated fatty acids (LCn3PUFA), vitamin D and fruit and vegetables portions makes it difficult to properly evaluate children's diets for these important dietary components.

Research limitations/implications

Future studies should use consistent age ranges and methods of dietary assessment to enable better comparisons. Research is needed to underpin child‐specific dietary guidelines for LCn3PUFA, fibre and vitamin D.

Originality/value

This paper gives a concise, up‐to‐date overview of the current diet quality of UK children.
Development of nutraceutical carriers for functional food applications
Authors: Nasirullah  , Kumar Pravin , Shariff Rizwan
Published: January 2011

Purpose

Nutraceuticals which have nutritional and therapeutic properties cannot be consumed directly due to their off flavor hence, a carrier in the form of microcapsules may be a better option for their application in foods. The purpose of this paper is to describe the preparation of nutraceutical barriers as microcapsulels.

Design/methodology/approach

Nutraceutical concentrates were isolated using methanol from sesame (Sesamum indicum), linseeds (Linum usitatissimum), black mustard (Brassica napus), yellow mustard (Brassica compestris) and niger seeds (Guizotai abyssinica) employing established protocol. These concentrates were further purified, enriching active ingredients using column chromatography to remove hydrocarbons, gums and other non‐polar inactive materials. These purified concentrates were subjected for sesamol, tocopherol, polyphenol and β‐carotene estimations. Subsequently, they were converted into microcapsules using spray drying, inclusion complexation and liposomal entrapment techniques.

Findings

The scanning electron microscope image of the spray‐dried nutraceutical concentrates isolated from sesame seeds showed that microcapsules were spherical in shape with 5‐25 μm in diameter with mean particle size of 10 μm with smooth outer surface and bee net like inner structure which yielded a uniform and smooth wall of microcapsules. Thickness of the wall was found to be 2‐5 μm. Sesamol, tocopherol, polyphenol and β‐carotene found to be ranging between 35,600 and 0; 14,520 and 890; 35,800 and 5,900 and 890 and 290 ppm. The encapsulation efficiency of spray drying, inclusion complexation and liposomal entrapment was 75.5, 54 and 58 percent, respectively, which considered to be good efficiency. The moisture content of the powders were found to be between 4 and 5 percent. The difference between the highest and the lowest moisture content at each relative humidity was about 0.5 percent. The percent nutraceutical concentrate adhering to the surface of granules during above encapsulation ranged between 1 and 5.5 percent.

Originality/value

Much work has been done on the nutraceuticals but information is very scarce on nutraceutical carriers. To carry the nutraceuticals to the site of delivery in intact form, nutraceutical carriers are inevitable. This paper describes how to prepare nutraceutical carriers as microcapsules by using spray drying, complexation and liposome entrapment procedures to obtain stable granules which can be used in food applications.
Health‐related content in Australian television advertising
Authors: Baker Julia Alice , Mullan Barbara Ann
Published: January 2011

Purpose

The purpose of this paper is to explore the proportions of health‐related content in non‐program time on Australian television, and how this relates to channel, product category, program genre and whether it is an advertisement or public service announcement (PSA).

Design/methodology/approach

Australian prime time television was recorded across three commercial television stations in Sydney. Non‐program content (NPC) was coded according to the channel, program genre, length of content and product advertised. In total, 44 hours of programming was recorded.

Findings

Not surprisingly, significant differences were found in the percentage of health‐related content between advertisements (22 percent) and PSAs (67 percent). Again unsurprisingly there was also a significant relationship between the product category and health‐related content (χ2=366.601, p=0.000), but also between health‐related content and program genre (χ2=20.594, p=0.024), particularly situation comedies (31 percent) and sport (15 percent). No difference was found in the percentage of health‐related content between the channels.

Research limitations/implications

Differences existing in the amount of NPC across program genre suggest that viewers of programs with high rates of health‐related content in advertising may have higher exposure to product dependant health information.

Originality/value

Health information is examined in a general sample without focus on particular demographics or health topics and the role of program genre is investigated.