bluuebunny/crossref_metadata_2025 huggingface dataset:
Double-periodic quasi-periodic graphene superlattice: non-Bragg band gap and electronic transport
Authors: Chen Xi , Zhao Pei-Liang , Zhu Qi-Biao
Published: November 2012

Electronic band gap and transport in quasi-periodic graphene superlattice (GSL) of double-periodic sequence are investigated. It is found that such quasi-periodic structure can possess a zero-averaged wave-number (zero-

) gap which is associated with an unusual Dirac point. Different from Bragg gap, the zero-

gap is less sensitive to the incidence angle, and robust against the lattice constants. The locations of Dirac point and multi-Dirac-points in the GSLs of various sequences are also compared. The control of electron transport over the zero-

band gap in GSLs may facilitate the development of many graphene-based electronics.
Automorphisms of Albert algebras and a conjecture of Tits and Weiss
Authors: Thakur Maneesh
Published: November 2012

Let

k
k

be a field of characteristic different from 2 and 3. The main aim of this paper is to prove the Tits-Weiss conjecture for Albert division algebras over

k
k

which are pure first Tits constructions. The conjecture asserts that, for an Albert division algebra

A
A

over a field

k
k

, the structure group

S
t
r
(
A
)

Str(A)

is generated by

U
U

-operators and scalar multiplications. The conjecture derives its importance from its connections with algebraic groups and Tits buildings, particularly with Moufang polygons. It is known that

k
k

-forms of

E
8

E_8

with index

E

8
,
2

78

E^{78}_{8,2}

and anisotropic kernel a strict inner

k
k

-form of

E
6

E_6

correspond bijectively (via Moufang hexagons) to Albert division algebras over

k
k

. The Kneser-Tits problem for a form of

E
8

E_8

as above is equivalent to the Tits-Weiss conjecture (see Section 3). We provide a solution to the Kneser-Tits problem for

k
k

-forms of

E
8

E_8

corresponding to pure first Tits construction Albert division algebras. As an application, we prove that for the

k
k

-group

G
=

Aut

(
A
)
,
 
G
(
k
)

/

R
=
1

G=\textbf {Aut}(A),~G(k)/R=1

, where

A
A

is an Albert division algebra over

k
k

as above and

R
R

stands for

R
R

-equivalence in the sense of Manin.
Error patterns in age estimation and tooth readability assignment of grey seals (Halichoerus grypus): results from a transatlantic, image-based, blind-reading study using known-age animals
Authors: Frie Anne K. , Hammill Mike O. , Hauksson Erlingur , Lind Ylva , Lockyer Christina , Stenman Olavi , Svetocheva Olga
Published: November 2012

Frie, A. K., Hammill, M. O., Hauksson, E., Lind, Y., Lockyer, C., Stenman, O., and Svetocheva, O. 2013. Error patterns in age estimation and tooth readability assignment of grey seals (Halichoerus grypus): results from a transatlantic, image-based, blind-reading study using known-age animals – ICES Journal of Marine Science, 70: 418–430. We analysed error patterns in a first interlaboratory grey seal (Halichoerus grypus) age-reading experiment. The experiment involved ten readers, who estimated age using images of cementum growth layers from teeth of 68 known-age seals (0–22 years). The percentages of correct estimates ranged from 32.4% to 60.3% among readers, and 89.3% of all errors were by ±1–2 years. Six readers showed increasing underageing with increasing seal age. An elevated risk of underestimation by 1 year occurred in teeth collected 0–5 months after breeding and was attributed to more frequent absence of a distinct growth layer for the new year and lack of information on months between the last birthday and the date of sample collection (plusmonths). For plusmonths 6–11, positive bias was predominant, suggesting that overestimation is the more common error when plusmonth information is available. Readers assigned readability scores to the tooth sections, and 79.1% of all ageing errors occurred in sections of low or intermediate readability. Excluding these sections would, however, also exclude 43.0% of all correct estimates. Neither levels of age estimation error nor predictive values of readability assignments were associated with reader experience levels. Analyses of image markings identified common errors in delineations of annual increment layers.
Spatial distribution of the stomach weights of juvenile anchovy (Engraulis encrasicolus L.) in the Bay of Biscay
Authors: Bachiller Eneko , Cotano Unai , Boyra Guillermo , Irigoien Xabier
Published: November 2012

Bachiller, E., Cotano, U., Boyra, G., and Irigoien, X. 2013. Spatial distribution of the stomach weights of juvenile anchovy (Engraulis encrasicolus L.) in the Bay of Biscay. – ICES Journal of Marine Science, 70: 362–378. Previous studies have shown that the survival of larval and juvenile anchovy off the continental shelf in the Bay of Biscay is not significantly different from that observed on the shelf, even though the food concentration is significantly higher on the shelf. In this paper we investigate the causes for the lack of relationship between food and survival for anchovy juvenile through analyses of feeding activity versus zooplankton distribution (in the transition from summer to fall from 2003 to 2010). The spatial distribution of the stomach weights of juvenile anchovy in relation to body size on and off the shelf revealed higher stomach fullness in areas off the shelf, where less zooplankton biomass was available. This result indicates that the food concentration is not always the main factor determining ingestion in fish. A situation of comparatively lesser prey abundance may provide better feeding conditions when combined with lower predation risk and lower light attenuation. In addition, the relatively heavier stomachs found in anchovies caught in years of higher recruitment indices suggest a large stomach content may be a symptom of good biological condition that may favour the winter survival of a larger fraction of the juvenile stock.
Occurrence of Fusarium commune and F. oxysporum in Horseradish Roots
Authors: Yu J. M. , Babadoost M.
Published: November 2012

This study was conducted to investigate the etiology of internal discoloration of horseradish roots. Several species of Fusarium and Verticillium were isolated from internally discolored horseradish roots collected from commercial fields in Illinois and research plots in Wisconsin during 2008 and 2009. Eleven isolates of Fusarium, identified as Fusarium oxysporum based on morphological features, were characterized by DNA sequencing of the nuclear translation elongation factor 1α (EF-1α) and mitochondrial small-subunit ribosomal DNA (mtSSU rDNA). Maximum parsimony analyses of DNA sequences from these two regions and the combined data set revealed that six isolates were clearly separated into a common clade that contained F. commune, with the remaining five isolates being grouped into a common clade with F. oxysporum. Based on the DNA sequence data, we considered the six isolates grouped into a common clade with F. commune to be F. commune. Pathogenicity tests of F. commune and F. oxysporum were conducted on two horseradish cultivars, ‘1573’ and ‘Big Top Western’, in a greenhouse. Root segments were inoculated by dipping them in a conidial suspension and then growing them in pots in a greenhouse for 4 months. For plants inoculated with F. commune, internal root discoloration and root rot developed 1 month after inoculation and almost all roots of the plant were completely rotten 4 months after inoculation. Inoculation of the plants with F. oxysporum resulted in only internal root discoloration but not root rot symptoms. This is the first report of F. commune causing internal discoloration and root rot of horseradish.
First Report of Hosta virus X Infecting Hosta Plants in China
Authors: Wei M. S. , Zhang Y. J. , Li G. F. , Ma J. , Li M.
Published: November 2012

Hosta (Hosta spp.) plants showing leaf deformation, puckering, and ink-bleed symptoms were collected in July 2012 from a park at Dongcheng district, Beijing, China. Three out of six samples tested positive for Hosta virus X (HVX) by immunostrip and double-antibody sandwich (DAS)-ELISA with HVX-specific serological reagents from Agdia Inc. (Elkhart, IN, USA). Filamentous viral particles were trapped and observed from the infected hosta leaf sap by immuno-serological electron microscopy (ISEM) (antibodies from Agdia). To confirm HVX infection, three ELISA-positive samples were analyzed by reverse transcription-PCR assay, using virus-specific primers HVXf (5′-ATCCGTTATCTACAGGGGACCAG-3′) and HVXr (5′-TAAGTTAGTGGAACGGTTAGCCCGAT-3′) that amplified a 1,067-bp fragment including the coat protein (CP) coding region. The CP nucleotide sequence comparisons showed 99% to 100% homology among the three isolates named HVXBJ4, HVXBJ5, and HVXBJ6 (GenBank Accession No. JX535292, JX535293, and JX535294) and with the HVX sequences previously reported in GenBank. HVX has been reported from the United States, Korea, the Netherlands, Poland, France, the Czech Republic, and New Zealand (1,2). To our knowledge, this is the first report of HVX infecting hosta plants in China. As an ornamental and medicinal plant, hosta has been cultivated in China for more than 2,000 years. The presence of HVX in Beijing is a potential threat to the landscape in the city. HVX can be spread by vegetative propagation material or mechanical contact (3). Hence, to cultivate HVX-free hosta and restrict the movement of HVX-infected hosta is vitally important in the future. HVX has become economically important in the world more recently. Globalization of trade in hosta plants has increased the risk of movement of HVX. The national plant protection organization should establish effective quarantine strategy and the growers take proper planting measures to avoid further spreading of this virus.

References: (1) S. Currier et al. Plant Dis. 80:1040, 1996. (2) M. H. Park et al. Arch. Virol. 148:2039, 2003. (3) K. H. Ryu et al. Acta Hortic. 722:91, 2006.
Colonization of Spinach by Verticillium dahliae and Effects of Pathogen Localization on the Efficacy of Seed Treatments
Authors: Maruthachalam Karunakaran , Klosterman Steven J. , Anchieta Amy , Mou Beiquan , Subbarao Krishna V.
Published: November 2012

Verticillium wilt on spinach (Spinacia oleracea) is caused by the soilborne fungus Verticillium dahliae. The pathogen is seedborne and transmission through seed is a major concern because of the dispersal of the pathogen to areas where fresh and processing spinach crops are grown in rotation with susceptible crops. Reduction in seedborne inoculum minimizes pathogen spread; therefore, knowledge of pathogen localization in seed is critical to develop methods to reduce seedborne inoculum. Spinach seedlings were inoculated with conidial suspensions of a green fluorescent protein-tagged strain of V. dahliae and colonization events were followed through seed production by confocal laser-scanning microscopy. Between 24 to 96 h postinoculation (PI), conidia germinated and formed hyphal colonies on root tips and in root elongation zones. Hyphae colonized root cortical tissues both intra and intercellularly by 2 weeks, and colonized the taproot xylem with abundant mycelia and conidia that led to vascular discoloration coincident with foliar symptom expression by 8 weeks PI. At 10 weeks PI, the xylem of the upper stem, inflorescence, and spinach seed parts, including the pericarp, seed coat, cotyledons, and radicle, had been colonized by the pathogen but not the perisperm (the diploid maternal tissue). Maximum concentration of the fungus was in the seed coat, the outermost layer of the vasculature. Infection of V. dahliae in spinach seed was systemic and transmissible to developing seedlings. Additional analyses indicated that fungicide and steam seed treatments reduced detectable levels of the pathogen but did not eliminate the pathogen from the seed. This information will assist in the development of seed treatments that will reduce the seedborne inoculum transmission to crop production fields.
Modeling Spatial Frailties in Survival Analysis of Cucurbit Downy Mildew Epidemics
Authors: Ojiambo P. S. , Kang E. L.
Published: November 2012

Cucurbit downy mildew caused by Pseudoperonospora cubensis is economically the most important disease of cucurbits globally, and the pathogen is disseminated aerially over a large spatial scale. Spatio-temporal spread of the disease was characterized during phase I (low and sporadic disease outbreaks) and II (rapid increase in disease outbreaks) of the epidemic using records collected from sentinel plots from 2008 to 2009 in 23 states in the eastern United States as part of the United States Department of Agriculture Cucurbit Downy Mildew ipmPIPE network. A substantive goal of this study was to explain the pattern of time to disease outbreak using important covariates while accounting for spatially correlated differences in risk of disease outbreak among the states. Survival analyses that accounts for spatial dependence were performed on time to disease outbreak, and posterior median frailties (or random effects) were mapped to identify states with high or low risk for disease outbreak. From February to October, disease occurred in 195 and 172 out of 413 and 556 cases monitored in 2008 and 2009, respectively. Disease outbreaks were spatially aggregated, with a spatial dependence of up to ≈1,025 km where clustering of outbreaks in phase I and II of the epidemic were similar. However, unlike in phase I of the epidemic, space–time point pattern analysis was significant (P < 0.0001) for outbreaks in phase II, during which the highest risk window as estimated by the space–time function was within 1.5 months and 500 km of the initial outbreak. The risk of disease outbreak peaked around July and decreased thereafter until the end of the study period. Spatially correlated analysis of time to disease outbreak indicated the need to incorporate spatial frailties in standard survival analysis models. Evaluation of alternative formulations of the spatial models demonstrated that a Bayesian hierarchical spatially structured frailty model best described time to disease outbreak. This frailty model showed clustering of outbreaks at the state level and indicated that states in the mid-Atlantic region have high spatial frailties and a high risk of downy mildew outbreak.
SIMULTANEOUS FZD4 AND LRP5 MUTATION IN AUTOSOMAL DOMINANT FAMILIAL EXUDATIVE VITREORETINOPATHY
Authors: Stiegel Evan , Say Emil A.T. , Carter B. Christian , Thomas Matthew J. , Shields Carol L.
Published: November 2012

Purpose:

The purpose of this study was to report simultaneous mutations of FZD4 and LRP5 genes associated with autosomal dominant familial exudative vitreoretinopathy in members of one family.

Methods:

Case report.

Results:

A 16-month-old white boy with a 6-month history of leukocoria was referred for possible retinoblastoma. On examination, the left eye displayed extensive white vitreoretinal fibrosis filling the entire vitreous cavity up to the lens and with additional dystrophic calcification and iris neovascularization. The right eye showed temporal peripheral fibrovascular ridge. Fluorescein angiography showed 360° of peripheral nonperfusion with leakage from the fibrovascular ridge of the right eye and diffuse leakage from the massive vitreoretinal fibrosis and iris neovascularization of the left eye, consistent with familial exudative vitreoretinopathy. Laser photocoagulation of the avascular areas of the right eye was performed with disease stabilization. Clinical examination and genetic testing of the family members demonstrated that the proband and a male sibling had similar clinical findings and simultaneous mutations in the FZD4 and LRP5 genes. Both affected patients had normal bone mineral dual-energy X-ray absorptiometry.

Conclusion:

Familial exudative vitreoretinopathy is a retinal vascular disorder usually caused by a single mutation. Rarely, multiple simultaneous mutations can occur and, in this case, result in classic ophthalmic phenotypic and known risk for bone disorders.
MICROBUBBLE IN THE HOLE
Authors: Tatlipinar Sinan , Yenerel N. Melda
Published: November 2012

Purpose:

To present a failed macular hole surgery with gas microbubble retention within the hole.

Methods:

A 68-year-old female patient with a Stage 2 macular hole underwent vitrectomy with removal of posterior hyaloid and 12% C3F8 gas injection. Because the macular hole was Stage 2 and posterior hyaloid was observed to be firmly attached over the macular area, no attempt was made for peeling of internal limiting membrane. Postoperatively, the patient was instructed to keep a facedown posture for 1 week. At 1-month visit, ophthalmoscopy revealed a tiny gas bubble filling the macular hole that failed to close.

Results:

The patient underwent a repeat vitrectomy in which internal limiting membrane was peeled, and the eye was filled with 20% SF6. At 2-week follow-up visit, the hole was observed to be closed.

Conclusion:

The reason for the macular hole nonclosure in this case may be the lack of internal limiting membrane peeling in the first operation. However, the authors believe that microbubble localized within the hole might have contributed to the failure.
Gastroesophageal Reflux Causing Sleep Interruptions in Infants
Authors: Machado Rodrigo , Woodley Frederick W. , Skaggs Beth , Di Lorenzo Carlo , Splaingard Mark , Mousa Hayat
Published: November 2012

Background and Aim:

Little is known about the relation between gastroesophageal reflux (GER) episodes and sleep interruptions in infants. The aim of the study was to evaluate the relationship between GER and the incidence of sleep interruptions in infants.

Methods:

Study patients included 24 infants (younger than 1 year) referred for multichannel intraluminal impedance and esophageal pH monitoring with simultaneous polysomnography. Exclusion criteria were a previous fundoplication and studies lasting <20 hours. Tests were clinically indicated to investigate suspicion of GER‐related apnea (17, 70.8%), stridor (6, 25%), noisy breathing (2, 8.3%), and cyanotic spells (1, 4.2%). Most patients presented with significant comorbidities (19, 79.2%).

Results:

The number of nonacid GER (NAGER) per hour was greater during sleep time than during daytime and awakening following sleep onset (median 0.27 vs 1.85 and 1.45, P < 0.01). A total of 1204 (range 7–86 per infant) arousals in 24 infants was detected, 165 (13.7%) that followed GER episodes, and 43 (3.6%) that preceded GER episodes. Seven patients presented with a positive symptom association probability for arousals; 5 were exclusively because of NAGER. A positive symptom association probability for awakenings was detected in 9 patients; 4 were because of NAGER, 4 were because of AGER, and 1 was because of both NAGER and GER. Patients with awakenings related to GER presented longer mean clearance time of AGER during sleep (165.5 vs 92.8 seconds, P = 0.03).

Conclusions:

GER was a frequent cause of interrupting sleep among our infant patients, and NAGER proved to be equally important as AGER for causing arousals and awakenings in infants.
Chimpanzees predict that a competitor's preference will match their own
Authors: Schmelz Martin , Call Josep , Tomasello Michael
Published: November 2012

The ability to predict how another individual will behave is useful in social competition. Chimpanzees can predict the behaviour of another based on what they observe her to see, hear, know and infer. Here we show that chimpanzees act on the assumption that others have preferences that match their own. All subjects began with a preference for a box with a picture of food over one with a picture of nothing, even though the pictures had no causal relation to the contents. In a back-and-forth food competition, chimpanzees then avoided the box with the picture of food when their competitor had chosen one of the boxes before them—presumably on the assumption that the competitor shared their own preference for it and had already chosen it. Chimpanzees predicted that their competitor's preference would match their own and adjusted their behavioural strategies accordingly.
Design, purification and characterization of a soluble variant of the integral membrane protein MotB for structural studies
Authors: Andrews Daniel A. , Xie Meng , Hughes Victoria , Wilce Matthew C. , Roujeinikova Anna
Published: November 2012

The bacterial flagellar motor is an intricate nanomachine powered by a transmembrane electrochemical gradient. Rotation is driven by the cumulative action of several peptidoglycan-anchored stator complexes on the rotor. In proton-motive force-driven motors, the stator complex is composed of a motility protein B (MotB) dimer surrounded by four copies of MotA, where both MotA and MotB are integral membrane proteins. The lack of full-length MotA and MotB structures hinders understanding of the mechanism of torque generation. Given the low levels of expression and low stability of detergent-solubilized MotB, a soluble chimaeric variant was engineered, where the two transmembrane helices of the MotB dimer were replaced by a leucine zipper. The biochemical and biophysical analysis of the resultant protein showed that it was properly folded, stable, behaved as a monodisperse dimer at low pH, had molecular dimensions close to those expected for native MotB and yielded reproducible crystals. The chimaeric protein is, therefore, a good candidate for structural studies. This ‘solubilization by design’ approach may be generally applicable to the production of soluble forms of other dimeric, trimeric and tetrameric single-span membrane proteins for functional and structural studies.
Asymmetric impact between liquid and solid wedges
Authors: Semenov Y. A. , Wu G. X.
Published: November 2012

The hydrodynamic problem of impact between a solid wedge and a liquid wedge is analysed. The liquid is assumed to be ideal and incompressible; gravity and surface tension effects are ignored. The flow generated by the impact is assumed to be irrotational and therefore can be described by the velocity potential theory. The solution procedure is based on the analytical derivation of the complex-velocity potential in a parameter plane and the function mapping conformally the parameter plane onto the similarity plane. The mapping function is found as a combination of the derivatives of the complex potential in the similarity and parameter planes, through the integral equations for mixed and homogeneous boundary-value problems in terms of the velocity modulus and the velocity angle with the fluid boundary, together with the dynamic and kinematic boundary conditions. These equations are solved through a numerical method. The procedure is first verified through comparisons with some known results. Simulations are then made for a variety of cases, and detailed results are presented in terms of the free surface shape, streamlines, pressure distribution on the wetted solid surface, and contact angles between the free surface and the body surface.
Genetic relatedness to sisters' children has been underestimated
Authors: Rogers Alan R.
Published: November 2012

Males of many species help in the care and provisioning of offspring, and these investments often correlate with genetic relatedness. For example, many human males invest in the children of sisters, and this is especially so where men are less likely to share genes with children of wives. Although this makes qualitative sense, it has been difficult to support quantitatively. The prevailing model predicts investment in children of sisters only when paternity confidence falls below 0.268. This value is often seen as too low to be credible; so investment in sisters' children represents an unsolved problem. I show here that the prevailing model rests on a series of restrictive assumptions that underestimate relatedness to sisters' children. For this reason, it understates the fitness payoff to men who invest in these children. This effect can be substantial, especially in societies with low confidence in paternity. But this effect cannot be estimated solely from confidence in paternity. One must also estimate the probability that two siblings share the same father.
Local and regional rarity in a diverse tropical fish assemblage
Authors: Hercos A. P. , Sobansky M. , Queiroz H. L. , Magurran A. E.
Published: November 2012

Because most species in an ecological assemblage are rare, much of the species richness we value is due to taxa with few individuals or a restricted distribution. It has been apparent since the time of ecological pioneers such as Bates and Darwin that tropical systems have disproportionately large numbers of rare species, yet the distribution and abundance patterns of these species remain largely unknown. Here, we examine the diversity of freshwater fish in a series of lakes in the Amazonian várzea, and relate relative abundance, both as numbers of individuals and as biomass, to the occurrence of species in space and time. We find a bimodal relationship of occurrence that distinguishes temporally and spatially persistent species from those that are infrequent in both space and time. Logistic regression reveals that information on occurrence helps distinguish those species that are rare in this locality but abundant elsewhere, from those that are rare throughout the region. These results form a link between different approaches used to evaluate commonness and rarity. In doing so, they provide a tool for identifying species of high conservation priority in poorly documented but species rich localities.
Phage loss and the breakdown of a defensive symbiosis in aphids
Authors: Weldon S. R. , Strand M. R. , Oliver K. M.
Published: November 2012

Terrestrial arthropods are often infected with heritable bacterial symbionts, which may themselves be infected by bacteriophages. However, what role, if any, bacteriophages play in the regulation and maintenance of insect–bacteria symbioses is largely unknown. Infection of the aphidAcyrthosiphon pisumby the bacterial symbiontHamiltonella defensaconfers protection against parasitoid wasps, but only whenH. defensais itself infected by the phageA. pisumsecondary endosymbiont (APSE). Here, we use a controlled genetic background and correlation-based assays to show that loss of APSE is associated with up to sevenfold increases in the intra-aphid abundance ofH. defensa. APSE loss is also associated with severe deleterious effects on aphid fitness: aphids infected withH. defensalacking APSE have a significantly delayed onset of reproduction, lower weight at adulthood and half as many total offspring as aphids infected with phage-harbouringH. defensa, indicating that phage loss can rapidly lead to the breakdown of the defensive symbiosis. Our results overall indicate that bacteriophages play critical roles in both aphid defence and the maintenance of heritable symbiosis.
Space-use scaling and home range overlap in primates
Authors: Pearce Fiona , Carbone Chris , Cowlishaw Guy , Isaac Nick J. B.
Published: November 2012

Space use is an important aspect of animal ecology, yet our understanding is limited by a lack of synthesis between interspecific and intraspecific studies. We present analyses of a dataset of 286 estimates of home range overlap from 100 primate species, with comparable samples for other space-use traits. To the best of our knowledge, this represents the first multispecies study using overlap data estimated directly from field observations. We find that space-use traits in primates are only weakly related to body mass, reflecting their largely arboreal habits. Our results confirm a theory that home range overlap explains the differences in allometric scaling between population density and home range size. We then test a suite of hypotheses to explain home range overlap, both among and within species. We find that overlap is highest for larger-bodied species living in large home ranges at high population densities, where annual rainfall is low, and is higher for arboreal than terrestrial species. Most of these results are consistent with the economics of resource defence, although the predictions of one specific theory of home range overlap are not supported. We conclude that home range overlap is somewhat predictable, but the theoretical basis of animal space use remains patchy.
Ploidy frequencies in plants with ploidy heterogeneity: fitting a general gametic model to empirical population data
Authors: Suda Jan , Herben Tomáš
Published: November 2012

Genome duplication (polyploidy) is a recurrent evolutionary process in plants, often conferring instant reproductive isolation and thus potentially leading to speciation. Outcome of the process is often seen in the field as different cytotypes co-occur in many plant populations. Failure of meiotic reduction during gametogenesis is widely acknowledged to be the main mode of polyploid formation. To get insight into its role in the dynamics of polyploidy generation under natural conditions, and coexistence of several ploidy levels, we developed a general gametic model for diploid–polyploid systems. This model predicts equilibrium ploidy frequencies as functions of several parameters, namely the unreduced gamete proportions and fertilities of higher ploidy plants. We used data on field ploidy frequencies for 39 presumably autopolyploid plant species/populations to infer numerical values of the model parameters (either analytically or using an optimization procedure). With the exception of a few species, the model fit was very high. The estimated proportions of unreduced gametes (median of 0.0089) matched published estimates well. Our results imply that conditions for cytotype coexistence in natural populations are likely to be less restrictive than previously assumed. In addition, rather simple models show sufficiently rich behaviour to explain the prevalence of polyploids among flowering plants.
Phenological response of sea turtles to environmental variation across a species' northern range
Authors: Mazaris Antonios D. , Kallimanis Athanasios S. , Pantis John D. , Hays Graeme C.
Published: November 2012

Variations in environmental parameters (e.g. temperature) that form part of global climate change have been associated with shifts in the timing of seasonal events for a broad range of organisms. Most studies evaluating such phenological shifts of individual taxa have focused on a limited number of locations, making it difficult to assess how such shifts vary regionally across a species range. Here, by using 1445 records of the date of first nesting for loggerhead sea turtles (Caretta caretta) at different breeding sites, on different continents and in different years across a broad latitudinal range (25–39° ′N), we demonstrate that the gradient of the relationship between temperature and the date of first breeding is steeper at higher latitudes, i.e. the phenological responses to temperature appear strongest at the poleward range limit. These findings support the hypothesis that biological changes in response to climate change will be most acute at the poleward range limits and are in accordance with the predictions of MacArthur's hypothesis that poleward range limit for species range is environmentally limited. Our findings imply that the poleward populations of loggerheads are more sensitive to climate variations and thus they might display the impacts of climate change sooner and more prominently.
Seasonality selects for more acutely virulent parasites when virulence is density dependent
Authors: Donnelly R. , Best A. , White A. , Boots M.
Published: November 2012

Host condition is often likely to influence parasite virulence. Furthermore, condition may often be correlated with host density, and therefore, it is important to understand the role of density-dependent virulence (DDV). We examine the consequences of DDV to the evolution of parasites in both seasonal and non-seasonal environments. In particular, we consider seasonality in host birth rate that results in a fluctuating host density and therefore a variable virulence. We show that parasites are selected for lower exploitation, and therefore lower transmission and virulence as the strength of DDV increases without seasonality. This is an important insight from our models; DDV has the opposite effect on the evolution of parasites to that of higher baseline mortality. Our key result is that although seasonality does not affect the evolution of virulence in classical models, with DDV parasites in seasonal environments are predicted to evolve to be more acute. This suggests that in more seasonal environments wildlife disease is likely to be more rather than less virulent if DDV is widespread.
Adiposity, compared with masculinity, serves as a more valid cue to immunocompetence in human mate choice
Authors: Rantala Markus J. , Coetzee Vinet , Moore Fhionna R. , Skrinda Ilona , Kecko Sanita , Krama Tatjana , Kivleniece Inese , Krams Indrikis
Published: November 2012

According to the ‘good genes’ hypothesis, females choose males based on traits that indicate the male's genetic quality in terms of disease resistance. The ‘immunocompetence handicap hypothesis’ proposed that secondary sexual traits serve as indicators of male genetic quality, because they indicate that males can contend with the immunosuppressive effects of testosterone. Masculinity is commonly assumed to serve as such a secondary sexual trait. Yet, women do not consistently prefer masculine looking men, nor is masculinity consistently related to health across studies. Here, we show that adiposity, but not masculinity, significantly mediates the relationship between a direct measure of immune response (hepatitis B antibody response) and attractiveness for both body and facial measurements. In addition, we show that circulating testosterone is more closely associated with adiposity than masculinity. These findings indicate that adiposity, compared with masculinity, serves as a more important cue to immunocompetence in female mate choice.
No evidence for directional evolution of body mass in herbivorous theropod dinosaurs
Authors: Zanno Lindsay E. , Makovicky Peter J.
Published: November 2012

The correlation between large body size and digestive efficiency has been hypothesized to have driven trends of increasing mass in herbivorous clades by means of directional selection. Yet, to date, few studies have investigated this relationship from a phylogenetic perspective, and none, to our knowledge, with regard to trophic shifts. Here, we reconstruct body mass in the three major subclades of non-avian theropod dinosaurs whose ecomorphology is correlated with extrinsic evidence of at least facultative herbivory in the fossil record—all of which also achieve relative gigantism (more than 3000 kg). Ordinary least-squares regressions on natural log-transformed mean mass recover significant correlations between increasing mass and geological time. However, tests for directional evolution in body mass find no support for a phylogenetic trend, instead favouring passive models of trait evolution. Cross-correlation of sympatric taxa from five localities in Asia reveals that environmental influences such as differential habitat sampling and/or taphonomic filtering affect the preserved record of dinosaurian body mass in the Cretaceous. Our results are congruent with studies documenting that behavioural and/or ecological factors may mitigate the benefit of increasing mass in extant taxa, and suggest that the hypothesis can be extrapolated to herbivorous lineages across geological time scales.
Impact of Residential Mobility on Exposure Assessment in Longitudinal Air Pollution Studies: A Sensitivity Analysis within the ESCAPE Project
Authors: Oudin Anna , Forsberg Bertil , Strömgren Magnus , Beelen Rob , Modig Lars
Published: November 2012

Exposure misclassification in longitudinal studies of air pollution exposure and health effects can occur due to residential mobility in a study population over followup. The aim of this study was to investigate to what extent residential mobility during followup can be expected to cause exposure misclassification in such studies, where exposure at the baseline address is used as the main exposure assessment. The addresses for each participant in a large population-based study (N>25,000) were obtained via national registers. We used a Land Use Regression model to estimate theNOxconcentration for each participant's all addresses during the entire follow-up period (in average 14.6 years) and calculated an average concentration during followup. The Land Use Regression model explained 83% of the variation in measured levels. In summary, theNOxconcentration at the inclusion address was similar to the average concentration over followup with a correlation coefficient of 0.80, indicating that air pollution concentration at study inclusion address could be used as indicator of average air pollution concentrations over followup. The differences between an individual's inclusion and average follow-up mean concentration were small and seemed to be nondifferential with respect to a large range of factors and disease statuses, implying that bias due to residential mobility was small.
Incidence and Survival of Patients with Small Intestinal Neuroendocrine Tumours in a Danish NET Center
Authors: Hoej Lise Brehm , Nykjær Karen Marie , Gronbaek Henning
Published: November 2012

Introduction. Small intestinal neuroendocrine tumours (NETs) have increased in incidence during the past decades. In recent years, new promising treatment modalities have been introduced. The aim of the present study was to characterize and compare patients with small intestinal NET seen in the periods 1994–2003 (group 1) and 2004–2011 (group 2) to demonstrate changes in incidence and survival in the two time periods.Patients and Methods. There were 52 NET patients in group 1 and 109 patients in group 2.Results. The incidence of small intestinal NET was 0.3/100.000/year in period 1 and 0.7/100.000/year in period 2. There was no difference in median chromogranin A levels (8709 versus 2381 pmol/L,P=0.107), presence of liver metastases (56% versus 44%), clinical symptoms (flushing/diarrhea), or Ki67 index (2% versus 2%), between the two time periods. The 5-year survival rate in the two time periods was similar, 64.7%, and 77.0%, respectively, (P=0.23).Conclusion. We observed an increase in the incidence of small intestinal NET during the period from January 1994 to December 2011, but we were not able to demonstrate an improved survival during the same time period.
Residues, Distributions, Sources, and Ecological Risks of OCPs in the Water from Lake Chaohu, China
Authors: Liu Wen-Xiu , He Wei , Qin Ning , Kong Xiang-Zhen , He Qi-Shuang , Ouyang Hui-Ling , Yang Bin , Wang Qing-Mei , Yang Chen , Jiang Yu-Jiao , Wu Wen-Jing , Xu Fu-Liu
Published: November 2012

The levels of 18 organochlorine pesticides (OCPs) in the water from Lake Chaohu were measured by a solid phase extraction-gas chromatography-mass spectrometer detector. The spatial and temporal distribution, possible sources, and potential ecological risks of the OCPs were analyzed. The annual mean concentration for the OCPs in Lake Chaohu was 6.99 ng/L. Aldrin, HCHs, and DDTs accounted for large proportions of the OCPs. The spatial pollution followed the order of Central Lakes > Western Lakes > Eastern Lakes and water area. The sources of the HCHs were mainly from the historical usage of lindane. DDTs were degraded under aerobic conditions, and the main sources were from the use of technical DDTs. The ecological risks of 5 OCPs were assessed by the species sensitivity distribution (SSD) method in the order of heptachlor > γ-HCH > p,p′-DDT > aldrin > endrin. The combining risks of all sampling sites were MS > JC > ZM > TX, and those of different species were crustaceans > fish > insects and spiders. Overall, the ecological risks of OCP contaminants on aquatic animals were very low.
Comparison of Two Methodologies for CD4+ T Lymphocytes Relative Counting on Immune Monitoring of Patients with Human Immunodeficiency Virus
Authors: Kalva Borato Danielle Cristyane , Carraro Emerson , Weber Ribas Sônia Regina , Kalva-Filho Carlos Augusto , Rebuglio Vellosa José Carlos
Published: November 2012

Considering that counting the percentage of CD4 T lymphocytes can add prognostic information regarding patients infected with HIV, the aim of this study was to evaluate the percentage values of CD4+ T lymphocytes from 81 patients determined by flow cytometry and estimated by flow cytometry in conjunction with a hematology counter. Means were compared through the Student'st-test. Pearson's correlation was determined, and the agreement between results was tested by Bland-Altman. The level of significance wasP<0.05. It was found a significantly higher mean difference between the relative values of CD4+ T lymphocytes to the hematologic counter (P<0.05), for all strata studied. Positive and significant correlations (P<0.01) were found between the strata CD4 < 200 cells/mL (r=0.93), between 200 and 500 cells/mL (r=0.65), and >500 cells/mL (r=0.81). The limits of agreement were1.0±3.8% for the stratum of CD4 < 200 cells/mL, approximately2.2±13.5% for the stratum of CD4 between 200 and 500 cells/mL, and approximately6.2±20.4% for the stratum > 500 cells/mL. The differences in the percentages of CD4+ T lymphocytes obtained by different methodologies could lead to conflict when used in clinical decisions related to the treatment and care of people infected with HIV.
Genome-wide mapping of human DNA-replication origins: Levels of transcription at ORC1 sites regulate origin selection and replication timing
Authors: Dellino Gaetano Ivan , Cittaro Davide , Piccioni Rossana , Luzi Lucilla , Banfi Stefania , Segalla Simona , Cesaroni Matteo , Mendoza-Maldonado Ramiro , Giacca Mauro , Pelicci Pier Giuseppe
Published: November 2012

We report the genome-wide mapping of ORC1 binding sites in mammals, by chromatin immunoprecipitation and parallel sequencing (ChIP-seq). ORC1 binding sites in HeLa cells were validated as active DNA replication origins (ORIs) using Repli-seq, a method that allows identification of ORI-containing regions by parallel sequencing of temporally ordered replicating DNA. ORC1 sites were universally associated with transcription start sites (TSSs) of coding or noncoding RNAs (ncRNAs). Transcription levels at the ORC1 sites directly correlated with replication timing, suggesting the existence of two classes of ORIs: those associated with moderate/high transcription levels (≥1 RNA copy/cell), firing in early S and mapping to the TSSs of coding RNAs; and those associated with low transcription levels (<1 RNA copy/cell), firing throughout the entire S and mapping to TSSs of ncRNAs. These findings are compatible with a scenario whereby TSS expression levels influence the efficiency of ORC1 recruitment at G1 and the probability of firing during S.
Functional Phosphoproteomic Analysis Reveals That a Serine-62-Phosphorylated Isoform of Ethylene Response Factor110 Is Involved in Arabidopsis Bolting
Authors: Zhu Lin , Liu Dandan , Li Yaojun , Li Ning
Published: November 2012

Ethylene is a major plant hormone that plays an important role in regulating bolting, although the underlying molecular mechanism is not well understood. In this study, we report the novel finding that the serine-62 (Ser-62) phosphorylation of Ethylene Response Factor110 (ERF110) is involved in the regulation of bolting time. The gene expression and posttranslational modification (phosphorylation) of ERF110 were analyzed among ethylene-response mutants and ERF110 RNA-interfering knockout lines of Arabidopsis (Arabidopsis thaliana). Physiological and biochemical studies revealed that the Ser-62 phosphorylation of ERF110 was closely related to bolting time, that is, the ethylene-enhanced gene expression of ERF110 and the decreased Ser-62 phosphorylation of the ERF110 protein in Arabidopsis. The expression of a flowering homeotic APETALA1 gene was up-regulated by the Ser-62-phosphorylated isoform of the ERF110 transcription factor, which was necessary but not sufficient for normal bolting. The gene expression and phosphorylation of ERF110 were regulated by ethylene via both Ethylene-Insensitive2-dependent and -independent pathways, which constitute a dual-and-opposing mechanism of action for ethylene in the regulation of Arabidopsis bolting.
Recombinant Antibody Production in Arabidopsis Seeds Triggers an Unfolded Protein Response
Authors: De Wilde Kirsten , De Buck Sylvie , Vanneste Kevin , Depicker Ann
Published: November 2012

Among the many plant-based production systems that are being tested for molecular farming, seeds are very attractive, as they provide a stable environment in which the accumulating recombinant proteins can be stored. However, it is not known exactly how high production levels of recombinant antibodies influence the endogenous transcriptome and proteome of the developing seed. To address this question, we studied the transcriptomic status in developing Arabidopsis (Arabidopsis thaliana) seeds 13 d post anthesis of three transgenic lines, producing varying levels of recombinant VHH or single-chain Fv antibody fragments fused to the human immunoglobulin G1-derived Fc fragment under the control of the β-PHASEOLIN seed-specific promoter. Using genome-wide Tiling arrays, we demonstrated that only a small proportion of the transcriptome was significantly changed in each of the lines compared with the wild type. Strikingly, in all three lines, we found a large overlap of up-regulated genes corresponding to protein folding, glycosylation/modification, translocation, vesicle transport, and protein degradation, suggestive of a state of cellular stress called the unfolded protein response. Moreover, the gene up-regulation amplitude was similar in all three lines. We hypothesize that the production of recombinant antibodies in the endoplasmic reticulum triggers endoplasmic reticulum stress, causing a disturbance of the normal cellular homeostasis.
Fe6.67(PO4)5.35(HPO4)0.65and Fe6.23(PO4)4.45(HPO4)1.55: two new mixed-valence iron phosphates
Authors: Dal Bo Fabrice , Hatert Frédéric
Published: November 2012

Two new mixed-valence iron phosphates, namely heptairon pentaphosphate hydrogen phosphate, Fe6.67(PO4)5.35(HPO4)0.65, and heptairon tetraphosphate bis(hydrogen phosphate), Fe6.23(PO4)4.45(HPO4)1.55, have been synthesized hydrothermally at 973 K and 0.1 GPa. The structures are similar to that of FeII3FeIII4(PO4)6and are characterized by infinite chains of Fe polyhedra parallel to the [101] direction. These chains are formed by the Fe1O6and Fe2O6octahedra, alternating with the Fe4O5distorted pentagonal bipyramids, according to the stacking sequence ...Fe1–Fe1–Fe4–Fe2–Fe2.... The Fe3O6octahedra and PO4tetrahedra connect the chains together. FeIIis localized on the Fe3 and Fe4 sites, whereas FeIIIis found in the Fe1 and Fe2 sites, according to bond-valence calculations. Refined site occupancies indicate the presence of vacancies on the Fe4 site, explained by the substitution mechanism FeII+ 2(PO43−) = vacancies + 2(HPO42−).