bluuebunny/crossref_metadata_2025 huggingface dataset:
Looking deeper into the structure of mixed electric double layers near the point of zero charge
Authors: Wang Zhi-Yong , Xie Yao-Ping , Liang Qing , Ma Zengwei , Wei Jianwei
Published: November 2012

Molecular simulations have been carried out using the Metropolis Monte Carlo approach to investigate the structure of planar electric double layers containing counterion mixture within the framework of the unrestricted primitive model. The results reveal that near the point of zero charge, the rise of monovalent salt drastically elevates the collapse of ions regardless of their polarity. In particular, we fail to observe the formation of a strongly correlated liquid in the first counterion layer due to favorable entropic effects, in contrast to the prediction of the hypernetted chain/mean spherical approximation integral equation for a spherical electric double layer [R. Messina, E. González-Tovar, M. Lozada-Cassou, and C. Holm, Europhys. Lett. 60, 383 (2002)10.1209/epl/i2002-00275-y]. Moreover, the large size of coions is found to be a pivotal factor in determining the reversal of electrophoretic mobility. On the other hand, the repulsive image charge forces thoroughly annihilate this peculiar reversal of mobility within the investigated scope of concentrations, but exert no effect on the emergence of charge reversal. These findings highlight potential applications of coion's characteristics to control gene delivery and colloidal stability as well as to design viral packing and polyelectrolyte self-assembly.
Temperature dependent effective mass in AlGaN/GaN high electron mobility transistor structures
Authors: Hofmann T. , Kühne P. , Schöche S. , Chen Jr-Tai , Forsberg U. , Janzén E. , Ben Sedrine N. , Herzinger C. M. , Woollam J. A. , Schubert M. , Darakchieva V.
Published: November 2012

The temperature-dependence of free-charge carrier mobility, sheet density, and effective mass of a two-dimensional electron gas in a AlGaN/GaN heterostructure deposited on SiC substrate is determined using the THz optical Hall effect in the spectral range from 0.22 to 0.32 THz for temperatures from 1.5 to 300 K. The THz optical Hall-effect measurements are combined with room temperature mid-infrared spectroscopic ellipsometry measurements to determine the layer thickness, phonon mode, and free-charge carrier parameters of the heterostructure constituents. An increase of the electron effective mass from (0.22±0.01)m0 at 1.5 K to (0.36±0.03)m0 at 300 K is observed, which is indicative for a reduction in spatial confinement of the two-dimensional electron gas at room temperature. The temperature-dependence of the mobility and the sheet density is in good agreement with electrical measurements reported in the literature.
Effects of laser irradiation on the self-assembly of MnAs nanoparticles in a GaAs matrix
Authors: Nam Hai Pham , Nomura Wataru , Yatsui Takashi , Ohtsu Motoichi , Tanaka Masaaki
Published: November 2012

We investigate the effects of laser irradiation on the self-assembly of MnAs nanoparticles during solid-phase decomposition in a GaAs matrix. It is found that laser irradiation suppresses the growth of MnAs nanoparticles from small to large size, and that the median diameter D1 in the size distribution of small MnAs nanoparticles depends on the incident photon energy E following D1 ∼ E−1/5. We explain this behavior by the desorption of Mn atoms on the MnAs nanoparticle surface due to resonant optical absorption, in which incident photons excite intersubband electronic transitions between the quantized energy levels in the MnAs nanoparticles.
Differential reflectance modulation sensing with diffractive microstructures
Authors: Kumawat N. , Varma M. M.
Published: November 2012

We present a method for differential ratiometric measurement of reflectance change due to molecular adsorption using a diffractive microstructure fabricated on a reflectance contrast enhancing substrate for bulk refractometry and surface molecular binding detection applications. The differential method suppresses signal fluctuations due to thermal or concentration gradients in the sample flow cell by more than 40× and enables the real-time measurement of molecular interactions on the surface with a noise floor of about 70 pm.
Domain formation in anatase TiO2 thin films on LaAlO3 substrates
Authors: Zheng Shijian , Fisher Craig A. J. , Kato Takeharu , Nagao Yuki , Ohta Hiromichi , Ikuhara Yuichi
Published: November 2012

Using advanced Cs-corrected scanning transmission electron microscopy, we have observed the atomic structures of coherent TiO2/LaAlO3 heterointerfaces in anatase TiO2 thin films deposited on single-crystal LaAlO3. Two epitaxial relationships are identified: (001)[100] TiO2//(001)[100] LaAlO3 and (001)[010] TiO2//(001)[100] LaAlO3. These epitaxial relationships and the terrace steps on the substrate surface result in the formation of multidomains in the anatase TiO2 thin films. Three types of domain boundaries are identified, namely, 90° rotation domain boundaries, translation domain boundaries, and mixtures of the two. These domain boundaries are expected to have a profound effect on the properties of the thin film.
Communication: An unusual halogen-bonding motif: The LiBr···BrF dimer as a model system
Authors: McDowell Sean A. C. , Joseph Jerelle A.
Published: November 2012

A stable complex, LiBr···BrF, is predicted in which the negative Br atom of LiBr is anchored to the Br atom of BrF by a halogen bond, while the positively charged Li atom interacts with the lone pair electron density on the Br atom of BrF in a direction roughly perpendicular to the halogen bond. As far as we are aware, this is the first reported instance of an atom of one diatomic molecule (Br of BrF) being bonded to two different, oppositely charged atoms (Li and Br) of another diatomic molecule (LiBr). Other less stable dimers of LiBr and BrF were predicted and compared with this novel complex.
Structure and physical properties of K0.63RhO2 single crystals
Authors: Yao S. H. , Zhang B. B. , Zhou J. , Chen Y. B. , Zhang S. T. , Gu Z. B. , Dong S. T. , Chen Y. F.
Published: November 2012

K0.63RhO2 single crystals were successfully grown by the flux method. Rietveld refinement of power X-ray diffraction patterns suggests that K0.63RhO2 belongs to the monoclinic P63mmc space group. Transport measurements on K0.63RhO2 revealed metallic behavior. The temperature-dependent resistance is well fitted by a different power law in two different temperature ranges. Antiferromagnetic ordering is observed in the ab-plane of K0.63RhO2 below 50 K. The most attractive feature of K0.63RhO2 is its significant Seebeck coefficient at room temperature (46 μV/cm), which is much greater than that of normal metals. Considered all together, the metallic conductivity, the significant Seebeck effect, and the non-hygroscopic properties of K0.63RhO2 make it a promising candidate material for thermoelectric applications.
Seedling growth, leaf water status and signature of stable carbon isotopes in C3 perennials exposed to natural phytochemicals
Authors: Hussain M. Iftikhar , Reigosa Manuel J.
Published: November 2012

In the present study, we evaluated the seedling growth, water status and signature of stable carbon isotopes in C3 perennial species exposed to natural phytochemicals. Three perennial species, cocksfoot (Dactylis glomerata), perennial ryegrass (Lolium perenne) and common sorrel (Rumex acetosa), were grown for 30 days in perlite, watered with Hoagland solution and exposed to the phytochemicals benzoxazolin-2(3H)-one (BOA) and cinnamic acid (CA) at 0, 0.1, 0.5, 1.0 and 1.5 mM concentrations. BOA markedly decreased the leaf and root fresh weights of D. glomerata and L. perenne in a concentration-dependent manner. The leaf fresh weight (LFW) of plants treated with CA (1.5 mM) was similarly affected by showing a decrease of LFW, being the lowest in L. perenne (56%) followed by D. glomerata (46%). The relative water contents of L. perenne, D. glomerata and R. acetosa were decreased while maximum RWC reduction was observed in L. perenne. Carbon isotope discrimination in L. perenne, D. glomerata and R. acetosa were reduced following treatment with BOA and CA at 1.5 mM. BOA at 1.5 mM decreased the ratio of intercellular to ambient CO2 concentration relative to control in L. perenne, D. glomerata and R. acetosa. There was an increase in water-use efficiency in L. perenne, D. glomerata and R. acetosa after treatment with BOA and CA. The dry weight of plants treated with CA (1.5 mM) showed different patterns of variation, being lowest in L. perenne (33%) followed by D. glomerata (3%) and R. acetosa (2%). Phytotoxicity was higher for the perennial grass than for the perennial broadleaf. These results clearly demonstrate a widespread occurrence of phytotoxicity among the three species, their tolerance and relationship between carbon isotope discrimination and intrinsic water-use efficiency.
Effect of varying glucose and glucosamine concentration in vitro on mouse oocyte maturation and developmental competence
Authors: Frank L. A. , Sutton-McDowall M. L. , Russell D. L. , Wang X. , Feil D. K. , Gilchrist R. B. , Thompson J. G.
Published: November 2012

The effects of hyper- and hypo-glycaemic conditions during the in vitro maturation of mouse cumulus–oocyte complexes on developmental competence were examined, with an emphasis on the role of the hexosamine biosynthesis pathway. A low (1 mM) glucose concentration achieved optimal oocyte competence (3-fold higher blastocyst development rate compared with high (30 mM) glucose, P < 0.05). In addition, glucose supplementation during only the first hour after release from the follicle was necessary and sufficient to support oocyte maturation and embryo development to the blastocyst stage. Glucosamine (a known hyperglycaemic mimetic and specific activator of the hexosamine pathway) was able to substitute for glucose during this first hour, indicating that flux through the hexosamine pathway is essential for oocyte competence. In the absence of glucose throughout the maturation period, glucosamine was not able to increase developmental competence, and at higher concentrations (2.5 and 5 mM) had a detrimental effect on MII and blastocyst development rates, compared with controls (P < 0.05). These experiments underscore the importance of glucose metabolic pathways during in vitro maturation and support the concept that excess flux through the hexosamine pathway has detrimental consequences.
The genetic mating system of the long-nosed potoroo (Potorous tridactylus) with notes on male strategies for securing paternity
Authors: Frankham Greta J. , Reed Robert L. , Eldridge Mark D. B. , Handasyde Kathrine A.
Published: November 2012

The potoroids are a small group of cryptic macropodoid marsupials that are difficult to directly monitor in the wild. Consequently, information regarding their social and mating systems is limited. A population of long-nosed potoroos (Potorous tridactylus) on French Island, Victoria, was monitored from June 2005 to August 2010. Tissue samples were collected from 32 (19 ♂, 13 ♀) independent potoroos and 17 pouch young. We aimed to determine the genetic mating system and identify patterns of paternity through genotyping individuals at 10 microsatellite loci. Additionally, we investigated the importance of body mass and site residency as strategies in securing paternity. Twelve of the 17 pouch young sampled were assigned paternity with confidence to five males. Multiple pouch young were sampled from two long-term resident females, one of which had 10 pouch young sired by multiple partners, with some repeat paternity, while the other had three young sired by one male, suggesting that the mating system is not entirely promiscuous. Sires were recorded on site for significantly longer periods than non-sires but were not significantly larger than non-sires at conception. This suggests that sires employ strategies other than direct competition, such as scramble competition, to secure paternity in P. tridactylus.
Counting primary loops in polymer gels
Authors: Zhou Huaxing , Woo Jiyeon , Cok Alexandra M. , Wang Muzhou , Olsen Bradley D. , Johnson Jeremiah A.
Published: November 2012

Much of our fundamental knowledge related to polymer networks is built on an assumption of ideal end-linked network structure. Real networks invariably possess topological imperfections that negatively affect mechanical properties; modifications of classical network theories have been developed to account for these defects. Despite decades of effort, there are no known experimental protocols for precise quantification of even the simplest topological network imperfections: primary loops. Here we present a simple conceptual framework that enables primary loop quantification in polymeric materials. We apply this framework to measure the fraction of primary loop junctions in trifunctional PEG-based hydrogels. We anticipate that the concepts described here will open new avenues of theoretical and experimental research related to polymer network structure.
Category-selective phase coding in the superior temporal sulcus
Authors: Turesson Hjalmar K. , Logothetis Nikos K. , Hoffman Kari L.
Published: November 2012

Object perception and categorization can occur so rapidly that behavioral responses precede or co-occur with the firing rate changes in the object-selective neocortex. Phase coding could, in principle, support rapid representation of object categories, whereby the first spikes evoked by a stimulus would appear at different phases of an oscillation, depending on the object category. To determine whether object-selective regions of the neo-cortex demonstrate phase coding, we presented images of faces and objects to two monkeys while recording local field potentials (LFP) and single unit activity from object-selective regions in the upper bank superior temporal sulcus. Single units showed preferred phases of firing that depended on stimulus category, emerging with the initiation of spiking responses after stimulus onset. Differences in phase of firing were seen below 20 Hz and in the gamma and high-gamma frequency ranges. For all but the <20-Hz cluster, phase differences remained category-specific even when controlling for stimulus-locked activity, revealing that phase-specific firing is not a simple consequence of category-specific differences in the evoked responses of the LFP. In addition, we tested for firing rate-to-phase conversion. Category-specific differences in firing rates accounted for 30–40% of the explained variance in phase occurring at lower frequencies (<20 Hz) during the initial response, but was limited (<20% of the explained variance) in the 30- to 60-Hz frequency range, suggesting that gamma phase-of-firing effects reflect more than evoked LFP and firing rate responses. The present results are consistent with theoretical models of rapid object processing and extend previous observations of phase coding to include object-selective neocortex.
How Do Biofuel Use Mandates Cause Uncertainty? United States Environmental Protection Agency Cellulosic Waiver Options
Authors: Meyer Seth , Thompson Wyatt
Published: November 2012

Biofuel policy in the United States sets minimum use mandates for different biofuels, but the cellulosic mandate, introduced in 2010 has been waived and reduced to nearly zero since then. This waiver has shifted the burden of compliance to other biofuels, but other options exist. We examine some alternatives using a structural model of biofuel, agricultural, and mandate markets. Our estimates show that crop price levels, crop and livestock farm income, compliance costs, and greenhouse gas emissions are all sensitive to whether and how the cellulosic mandate is waived. Mandate analysis that does not consider Environmental Protection Agency implementation, or waiver analysis that disregards the hierarchical nature of the mandates could be misleading.
Evidence of accretion triggered oscillations in the pre-main-sequence interacting binary AK Sco
Authors: Gómez de Castro Ana I. , López-Santiago Javier , Talavera Antonio
Published: November 2012

Pre-main sequence (PMS) binaries are surrounded by circumbinary discs from which matter falls on to both components. The material dragged from the circumbinary disc flows on to each star through independent streams channelled by the variable gravitational field. The action of the bar-like potential is most prominent in high eccentricity systems made of two equal mass stars. AK Sco is a unique PMS system composed of two F5 stars in an orbit with e = 0.47. Henceforth, it is an ideal laboratory to study matter infall in binaries and its role in orbit circularization. In this Letter, we report the detection of a 1.3 mHz ultra low-frequency oscillation in the ultraviolet light curve at periastron passage. This oscillation lasts 7 ks being most likely fed by the gravitational energy released when the stream's tails spiralling on to each star get in contact at periastron passage enhancing the accretion flow; this unveils a new mechanism for angular momentum loss during PMS evolution and a new type of interacting binary.
Conditional Requirement for Exopolysaccharide in the Mesorhizobium–Lotus Symbiosis
Authors: Kelly Simon J. , Muszyński Artur , Kawaharada Yasuyuki , Hubber Andree M. , Sullivan John T. , Sandal Niels , Carlson Russell W. , Stougaard Jens , Ronson Clive W.
Published: November 2012

Rhizobial surface polysaccharides are required for nodule formation on the roots of at least some legumes but the mechanisms by which they act are yet to be determined. As a first step to investigate the function of exopolysaccharide (EPS) in the formation of determinate nodules, we isolated Mesorhizobium loti mutants affected in various steps of EPS biosynthesis and characterized their symbiotic phenotypes on two Lotus spp. The wild-type M. loti R7A produced both high molecular weight EPS and lower molecular weight (LMW) polysaccharide fractions whereas most mutant strains produced only LMW fractions. Mutants affected in predicted early biosynthetic steps (e.g., exoB) formed nitrogen-fixing nodules on Lotus corniculatus and L. japonicus ‘Gifu’, whereas mutants affected in mid or late biosynthetic steps (e.g., exoU) induced uninfected nodule primordia and, occasionally, a few infected nodules following a lengthy delay. These mutants were disrupted at the stage of infection thread (IT) development. Symbiotically defective EPS and Nod factor mutants functionally complemented each other in co-inoculation experiments. The majority of full-length IT observed harbored only the EPS mutant strain and did not show bacterial release, whereas the nitrogen-fixing nodules contained both mutants. Examination of the symbiotic proficiency of the exoU mutant on various L. japonicus ecotypes revealed that both host and environmental factors were linked to the requirement for EPS. These results reveal a complex function for M. loti EPS in determinate nodule formation and suggest that EPS plays a signaling role at the stages of both IT initiation and bacterial release.
Field Resistance to the Ug99 Race Group of the Stem Rust Pathogen in Spring Wheat Landraces
Authors: Newcomb M. , Acevedo M. , Bockelman H. E. , Brown-Guedira G. , Goates B. J. , Jackson E. W. , Jin Y. , Njau P. , Rouse M. N. , Singh D. , Wanyera R. , Bonman J. M.
Published: November 2012

Wheat landraces provide a source of genetic variability for breeding. The emergence and spread of highly virulent races of the stem rust pathogen (Ug99 race group of Puccinia graminis f. sp. tritici) threaten wheat production globally. Spring wheat landraces were screened for resistance in eight field seasons at the Kenya Agricultural Research Institute, Njoro, where the Ug99 race group has become endemic. Accessions showing resistance in one season were retested and screened with molecular markers associated with resistance genes Sr2, Sr24, Sr36, and Lr34/Yr18; two height-reducing genes; and a photoperiod insensitivity allele. Of 2,509 accessions tested, 278 were categorized as resistant based on results from at least two seasons. Of these resistant accessions, 32 were positive for one or more markers for Sr2, Sr36, Rht-B1b, or Rht-D1b, indicating that they do not fit the definition of “landrace” because these genes were likely introduced via modern breeding practices. Thus, 246 resistant “landrace” accessions were identified. Of countries with more than five tested accessions, Afghanistan, Iran, Portugal, Ethiopia, Uzbekistan, Greece, Tajikistan, Bosnia and Herzegovina, and Serbia had at least 10% of tested accessions that were resistant to the Ug99 race group. Future research will characterize the resistance to determine its novelty and incorporate novel genes into improved lines.
Effects of Temperature and Wetness Duration on the Sporulation Rate ofPhomopsis viticolaon Infected Grape Canes
Authors: Anco D. J. , Madden L. V. , Ellis M. A.
Published: November 2012

Controlled-environment studies were conducted to examine effects of temperature (T) and wetness duration (W) on the sporulation rate of Phomopsis viticola on infected grape canes and to determine effects of interrupted wetness duration (IWD) on sporulation. A split-plot design was used to determine T and W effects, with T (5, 12, 15, 18, 20, 22, 25, 28, and 35°C) as the whole-plot and W (11, 23, 35, 47, and 71 h) as the subplot. Linear and nonlinear mixed models were fitted to the data. Lower and upper limits of sporulation were estimated to be 4 and 36°C, respectively, based on the modeling results, optimum sporulation was near 21°C, and sporulation increased monotonically with increasing wetness duration. Of the examined models, a generalization of the Analytis Beta model fit the data best, based on a collection of goodness-of-fit statistical criteria. To determine effects of IWD, a split-plot was used, with T (12, 15, and 20°C) as the whole-plot and IWD (0, 2, 4, 8, 12, and 24 h) as the subplot. Generally, sporulation declined with increasing IWD. An IWD of 8 h or more resulted in significantly and substantially less sporulation compared to the control (0 h IWD) (P < 0.01). Temporal patterns of spore density in the field were determined using a repeated-measures design, in which spore density and environmental data were measured in the vineyard during and following individual rain events over 3 years. The developed model from the controlled-environment study, coupled with a time-of-season weight function and a dispersal index (based on total rain per rain episode), predicted the trend in spore density over time reasonably well, although the total magnitude of spore density could not be predicted because the density of lesions was not known. Results can be used for improving the accuracy of a disease warning system that currently only considers infection of grapes by P. viticola.
First Report of Group 16SrXII-A Phytoplasma Causing Stolbur Disease in Saponaria officinalis Plants in Serbia
Authors: Josic D. , Starovic M. , Stojanovic S. , Popovic T. , Dolovac N. , Zdravkovic J. , Pavlovic S.
Published: November 2012

Saponaria officinalis L. (Caryophyllaceae; also known as bouncingbet or soapwort) is a perennial medicinal plant important for the pharmaceutical industry and used as an expectorant, alterative, laxative, and ointment for some skin diseases and arthritic conditions. S. officinalis plants with typical symptoms (23% in 2011 and 47% in 2012) of phytoplasma infection were observed in Pancevo plantation, Serbia. The symptoms appeared in May with leaves changing color from green to brown with severe reddening and necrosis. Severely diseased plants died. The infected plants had a significant reduction in biomass and quality. To investigate the presence of phytoplasma, total DNA was extracted from 10 symptomatic and four asymptomatic plants by a CTAB method. The nested PCR was carried out using phytoplasma-specific primer set P1/16S-SR followed by R16F2n/R16R2, targeting the 16S rRNA gene sequence of 1.5 and 1.2 kb in length, respectively. The amplicons of expected size were obtained from the symptomatic plants, but not from the asymptomatic plants. To obtain restriction fragment length polymorphism (RFLP) patterns, the R16F2n/R2 amplicons were digested with AluI, TruI1, HpaII, and HhaI endonucleases. The resulting patterns indicated that seven plants were infected by a Stolbur phytoplasma belonging to the 16SrXII-A subgroup, since it had the identical RFLP pattern as the STOL reference strain. The 1.2 kb nested PCR products of representative isolate Sap7 were purified using PCR purification kit (Fermentas, Vilnius, Lithuania) according to the recommended protocol and sequenced using facilities of IMGGI SeqService, Belgrade, Serbia. The obtained sequence was deposited in the NCBI database (GenBank Accession No. JX866951). The phytoplasma 16S rRNA gene sequence from Sap7 had a sequence identity of 97% with GenBank accessions GQ273961.1 (‘Euonymus japonicus’ phytoplasma), JX311953.1 (Candidatus Phytoplasma solani clone 5043), JQ412100.1 (Iranian alfalfa phytoplasma M21), and JN561702.1 (‘Convolvulus arvensis’ stolbur phytoplasma clone P1/P7-Conv2/2010-Bg). To our knowledge, this is the first report of a natural infection of S. officinalis by 16SrXII-A subgroup (Stolbur) phytoplasma in Serbia. As cited by Lee et al. (1), the 16SrI-M subgroup phytoplasma in S. officinalis sample was already detected in Lithuania by Valiunas (2). The identification of phytoplasma in the Pancevo plantation caused the intensification of our biological control tests and efforts to reduce the ecological and economic impacts of these phytoplasmas.

References: (1) I. M. Lee et al. Int. J. Syst. Evol. Microbiol. 54:1037, 2004. (2) D. Valiunas. PhD thesis, Institute of Botany, Vilnius, Lithuania, 2003.
Passive rafting is a powerful driver of transoceanic gene flow
Authors: Nikula Raisa , Spencer Hamish G. , Waters Jonathan M.
Published: November 2012

Dispersal by passive oceanic rafting is considered important for the assembly of biotic communities on islands. However, not much is known about levels of population genetic connectivity maintained by rafting over transoceanic distances. We assess the evolutionary impact of kelp-rafting by estimating population genetic differentiation in three kelp-associated invertebrate species across a system of islands isolated by oceanic gaps for over 5 million years, using mtDNA and AFLP markers. The species occur throughout New Zealand's subantarctic islands, but lack pelagic stages and any opportunity for anthropogenic transportation, and hence must rely on passive rafting for long-distance dispersal. They all have been directly observed to survive transoceanic kelp-rafting journeys in this region. Our analyses indicate that regular gene flow occurs among populations of all three species between all of the islands, especially those on either side of the subtropical front oceanographic boundary. Notwithstanding its perceived sporadic nature, long-distance kelp-rafting appears to enable significant gene flow among island populations separated by hundreds of kilometres of open ocean.
A low trophic position of Japanese eel larvae indicates feeding on marine snow
Authors: Miller Michael J. , Chikaraishi Yoshito , Ogawa Nanako O. , Yamada Yoshiaki , Tsukamoto Katsumi , Ohkouchi Naohiko
Published: November 2012

What eel larvae feed on in the surface layer of the ocean has remained mysterious. Gut contents and bulk nitrogen stable isotope studies suggested that these unusual larvae, called leptocephali, feed at a low level in the oceanic food web, whereas other types of evidence have suggested that small zooplankton are eaten. In this study, we determined the nitrogen isotopic composition of amino acids of both natural larvae and laboratory-reared larvae of the Japanese eel to estimate the trophic position (TP) of leptocephali. We observed a mean TP of 2.4 for natural leptocephali, which is consistent with feeding on particulate organic matter (POM) such as marine snow and discarded appendicularian houses containing bacteria, protozoans and other biological materials. The nitrogen isotope enrichment values of the reared larvae confirm that the primary food source of natural larvae is consistent only with POM. This shows that leptocephali feed on readily available particulate material originating from various sources closely linked to ocean primary production and that leptocephali are a previously unrecognized part of oceanic POM cycling.
Between cheap and costly signals: the evolution of partially honest communication
Authors: Zollman Kevin J. S. , Bergstrom Carl T. , Huttegger Simon M.
Published: November 2012

Costly signalling theory has become a common explanation for honest communication when interests conflict. In this paper, we provide an alternative explanation for partially honest communication that does not require significant signal costs. We show that this alternative is at least as plausible as traditional costly signalling, and we suggest a number of experiments that might be used to distinguish the two theories.
Viral mutation rates: modelling the roles of within-host viral dynamics and the trade-off between replication fidelity and speed
Authors: Regoes Roland R. , Hamblin Steven , Tanaka Mark M.
Published: November 2012

Many viruses, particularly RNA viruses, mutate at a very high rate per genome per replication. One possible explanation is that high mutation rates are selected to meet the challenge of fluctuating environments, including the host immune response. Alternatively, recent studies argue that viruses evolve under a trade-off between replication speed and fidelity such that fast replication is selected, and, along with it, high mutation rates. Here, in addition to these factors, we consider the role of viral life-history properties: namely, the within-host dynamics of viruses resulting from their interaction with the host. We develop mathematical models incorporating factors occurring within and between hosts, including deleterious and advantageous mutations, host death owing to virulence and clearance of viruses by the host. Beneficial mutations confer both a within-host and a transmission advantage. First, we find that advantageous mutations have only a weak effect on the optimal genomic mutation rate. Second, viral life-history properties have a large effect on the mutation rate. Third, when the speed–fidelity trade-off is included, there can be two locally optimal mutation rates. Our analysis provides a way to consider how life-history properties combine with biochemical trade-offs to shape mutation rates.
Palaeoecological evidence of a historical collapse of corals at Pelorus Island, inshore Great Barrier Reef, following European settlement
Authors: Roff George , Clark Tara R. , Reymond Claire E. , Zhao Jian-xin , Feng Yuexing , McCook Laurence J. , Done Terence J. , Pandolfi John M.
Published: November 2012

The inshore reefs of the Great Barrier Reef (GBR) have undergone significant declines in water quality following European settlement (approx. 1870 AD). However, direct evidence of impacts on coral assemblages is limited by a lack of historical baselines prior to the onset of modern monitoring programmes in the early 1980s. Through palaeoecological reconstructions, we report a previously undocumented historical collapse of
Acropora
assemblages at Pelorus Island (central GBR). High-precision U-series dating of dead
Acropora
fragments indicates that this collapse occurred between 1920 and 1955, with few dates obtained after 1980. Prior to this event, our results indicate remarkable long-term stability in coral community structure over centennial scales. We suggest that chronic increases in sediment flux and nutrient loading following European settlement acted as the ultimate cause for the lack of recovery of
Acropora
assemblages following a series of acute disturbance events (SST anomalies, cyclones and flood events). Evidence for major degradation in reef condition owing to human impacts prior to modern ecological surveys indicates that current monitoring of inshore reefs on the GBR may be predicated on a significantly shifted baseline.
First description of a musculoskeletal linkage in an adipose fin: innovations for active control in a primitively passive appendage
Authors: Stewart Thomas A. , Hale Melina E.
Published: November 2012

Adipose fins are enigmatic appendages found between the dorsal and caudal fins of some teleostean fishes. Long thought to be vestigial, degenerate second dorsal fins, remnants of the primitive gnathostome condition, adipose fins have since been recognized as novel morphologies. Unique among the fins of extant fishes, adipose fins have uniformly been described as passive structures, with no associated musculature. Here we provide the first description of a musculoskeletal linkage in an adipose fin, identified in the sun catfishHorabagrus brachysoma. Modified supracarinalis posterior muscles insert from the dorsal midline anterior to the adipose fin by tendons onto the fin base. An additional pair of posterior adipose-fin muscles also inserts upon the fin base and lay posterolateral to the fin, superficial to the axial muscle. This musculoskeletal linkage is an evolutionary innovation, a novel mechanism for controlling adipose-fin movement. These muscles appear to exemplify two approaches by which fins evolve to be actively controlled. We hypothesize that the anterior muscles arose through co-option of an existing fin linkage, while the posterior muscles originated as de novo fin muscles. These findings present adipose fins as a rich system within which to explore the evolution of novel vertebrate appendages.
Integrative modelling of animal movement: incorporatingin situhabitat and behavioural information for a migratory marine predator
Authors: Bestley Sophie , Jonsen Ian D. , Hindell Mark A. , Guinet Christophe , Charrassin Jean-Benoît
Published: November 2012

A fundamental goal in animal ecology is to quantify how environmental (and other) factors influence individual movement, as this is key to understanding responsiveness of populations to future change. However, quantitative interpretation of individual-based telemetry data is hampered by the complexity of, and error within, these multi-dimensional data. Here, we present an integrative hierarchical Bayesian state-space modelling approach where, for the first time, the mechanistic process model for the movement state of animals directly incorporates both environmental and other behavioural information, and observation and process model parameters are estimated within a single model. When applied to a migratory marine predator, the southern elephant seal (Mirounga leonina), we find the switch from directed to resident movement state was associated with colder water temperatures, relatively short dive bottom time and rapid descent rates. The approach presented here can have widespread utility for quantifying movement–behaviour (diving or other)–environment relationships across species and systems.
Targeted gene silencing in mouse germ cells by insertion of a homologous DNA into a piRNA generating locus
Authors: Yamamoto Yasuhiro , Watanabe Toshiaki , Hoki Yuko , Shirane Kenjiro , Li Yufeng , Ichiiyanagi Kenji , Kuramochi-Miyagawa Satomi , Toyoda Atsushi , Fujiyama Asao , Oginuma Masayuki , Suzuki Hitomi , Sado Takashi , Nakano Toru , Sasaki Hiroyuki
Published: November 2012

In germ cells, early embryos, and stem cells of animals, PIWI-interacting RNAs (piRNAs) have an important role in silencing retrotransposons, which are vicious genomic parasites, through transcriptional and post-transcriptional mechanisms. To examine whether the piRNA pathway can be used to silence genes of interest in germ cells, we have generated knock-in mice in which a foreign DNA fragment was inserted into a region generating pachytene piRNAs. The knock-in sequence was transcribed, and the resulting RNA was processed to yield piRNAs in postnatal testes. When reporter genes possessing a sequence complementary to portions of the knock-in sequence were introduced, they were greatly repressed after the time of pachytene piRNA generation. This repression mainly occurred at the post-transcriptional level, as degradation of the reporter RNAs was accelerated. Our results show that the piRNA pathway can be used as a tool for sequence-specific gene silencing in germ cells and support the idea that the piRNA generating regions serve as traps for retrotransposons, enabling the host cell to generate piRNAs against active retrotransposons.
TALP: a multisolution direct-space strategy for solving molecular crystals from powder diffraction data based on restrained least squares
Authors: Vallcorba Oriol , Rius Jordi , Frontera Carlos , Miravitlles Carles
Published: November 2012

TALP is a new direct-space strategy forab initiocrystal structure determination of molecular crystals from powder diffraction data. The strategy is based on a preliminary exploration stage, which considers atomic overlap, followed by a subsequent stage of local incremental scans, both coupled to fast restrained least-squares minimizations with the atomic coordinates as refined parameters. The observed intensities are extracted from the powder pattern by a three-step procedure [Vallcorba, Rius, Frontera, Peral & Miravitlles (2012).J. Appl. Cryst.45, 844–848], and the molecular model and distance restraints are derived from molecular mechanics calculations or from similar reported structures. The solution process consists of several independent trials, each one resulting in a crystal structure proposal with an associated figure of merit. TALP has been tested on laboratory X-ray powder diffraction data of 14 molecular compounds of known crystal structure and of variable complexity. In most cases, the crystal structure is solved in a short time (less than an hour), even for calculated models. For the most complex structures (e.g.13 torsion angles), the general scan is assisted by a rotation function, which provides a ranked list of most probable model orientations. In this way only the positional and conformation parameters need to be explored.
The fatty acid profile of Chinese Maiwa yak milk in relation to season and parity
Authors: He Sheng‐Hua , Ma Ying , Li Qi‐Ming , Li De‐Hai , Wang Jia‐Qi , Cui Yah‐Hua
Published: November 2012

The fatty acid profiles of Chinese Maiwa yak milk samples were evaluated at different seasons (n = 96) and parities (n = 32). Saturated fatty acid content and monounsaturated fatty acid content showed no significant difference (P > 0.05) between warm season and cold season; however, polyunsaturated fatty acid (PUFA) content in warm season was higher (P < 0.05) than in cold season. Monounsaturated fatty acid and PUFA contents were higher (P < 0.05) in multiparous Maiwa yak milk than in primiparous Maiwa yak milk. Trans‐11C18:1, cis‐9, cis‐12C18:2, CLA and C18:3 contents were higher (P < 0.05) in multiparous Maiwa yak than in primiparous Maiwa yak milk.
Arthropod prey of imported fire ants (Hymenoptera: Formicidae) in Mississippi sweetpotato fields
Authors: Rashid Tahir , Chen Jian , Vogt James T. , McLeod Paul J.
Published: November 2012

The red imported fire ants, Solenopsis invicta (Buren), are generally considered pests. They have also been viewed as beneficial predators feeding on other insect pests of various agroecosystems. This study documents the foraging habits of fire ants in a sweetpotato field in Mississippi. Fire ant foraging trails connecting outside colonies to a sweetpotato field were exposed and foraging ants moving out of the field toward the direction of the colony were collected along with the solid food particles they were carrying. The food material was classified as arthropod or plant in origin. The arthropod particles were identified to orders. Fire ant foragers carried more arthropods than plant material. Coleoptera and Homoptera were the most abundant groups preyed upon. These insect orders contain various economically important pests of sweetpotato. Other major hexapod groups included the orders Hemiptera, Diptera and Collembola. The quantity of foraged material varied over the season. No damage to sweetpotato roots could be attributed to fire ant feeding. Imported fire ant foraging may reduce the number of insect pests in sweetpotato fields.
Efficacy of Acamprosate for Alcohol Dependence in a Family Medicine Setting in the United States: A Randomized, Double‐Blind, Placebo‐Controlled Study
Authors: Berger Lisa , Fisher Michael , Brondino Michael , Bohn Michael , Gwyther Robert , Longo Lance , Beier Nicole , Ford Amy , Greco Joe , Garbutt James C.
Published: November 2012

Background

Acamprosate has been found to enhance rates of complete abstinence and to increase percent days abstinent (PDA) from alcohol relative to placebo treatment. As most U.S. clinical trials of acamprosate have been conducted in alcohol and other drug specialty clinics, there is a need to examine the efficacy of acamprosate in generalist settings. This study tested the efficacy of acamprosate versus placebo on the primary study outcome of PDA in the treatment of alcohol‐dependent patients in a family medicine setting. Secondary study outcomes included percent heavy drinking days (%HDD) and gamma glutamyltransferase level (normal or high).

Methods

A randomized, double‐blind, placebo‐controlled, parallel group design of acamprosate was conducted in 2 family medicine settings (North Carolina and Wisconsin). One hundred volunteers were recruited primarily by advertisement, and participants were assigned to 666 mg (2 pills) oral acamprosate 3 times daily (1,998 mg/d) or matching placebo over a 12‐week period. All participants concomitantly received 5 sessions of a brief behavioral intervention from a family/primary care physician.

Results

No significant treatment effect of acamprosate was found on PDA or the secondary outcomes. Significant treatment goal by time interaction effects was found on PDA and %HDD. Participants who had an initial goal of abstinence versus a reduction in alcohol use improved on average over time in PDA and had less %HDD from baseline to the end of treatment.

Conclusions

This clinical trial did not find evidence of efficacy for acamprosate compared to placebo among alcohol‐dependent individuals recruited primarily by advertisement as studied in a primary care setting. Drinking outcomes significantly improved regardless of medication condition. A goal of abstinence was significantly associated with improved drinking outcomes, suggesting that alcohol‐dependent patients with such a goal may do particularly well with counseling in a family medicine setting.
Metabolic and Biochemical Effects of Low‐to‐Moderate Alcohol Consumption
Authors: Whitfield John B. , Heath Andrew C. , Madden Pamela A. F. , Pergadia Michele L. , Montgomery Grant W. , Martin Nicholas G.
Published: November 2012

Background

Alcohol consumption has multiple biochemical consequences. Only a few of these are useful as diagnostic markers, but many reflect potentially harmful or beneficial effects of alcohol. Average consumption of 2 to 4 drinks per day is associated with lower overall or cardiovascular mortality risk than either lower or higher intake. We have analyzed the dose–response relationships between reported alcohol consumption and 17 biomarkers, with emphasis on intake of up to 3 drinks per day.

Methods

Biochemical tests were performed on serum from 8,396 study participants (3,750 men and 4,646 women, aged 51 ± 13 years, range 18 to 93) who had provided information on alcohol consumption in the week preceding blood collection.

Results

Gamma glutamyl transferase, alanine aminotransferase, aspartate aminotransferase, carbohydrate‐deficient transferrin, urate, ferritin, and bilirubin showed little or no change with alcohol consumption below 2 to 3 drinks per day, but increased with higher intake. High‐density lipoprotein cholesterol and albumin showed increasing results, and insulin showed decreasing results, across the entire range of alcohol use. Biphasic responses, where subjects reporting 1 to 2 drinks per day had lower results than those reporting either more or less alcohol use, occurred for triglycerides, glucose, C‐reactive protein, alkaline phosphatase, and butyrylcholinesterase. Increasing alcohol use was associated with decreasing low‐density lipoprotein cholesterol (LDL‐C) in younger women, but higher LDL‐C in older men.

Conclusions

Some markers show threshold relationships with alcohol, others show continuous ones, and a third group show biphasic or U‐shaped relationships. Overall, the biochemical sequelae of low‐to‐moderate alcohol use are consistent with the epidemiological evidence on morbidity and mortality.
13‐Cis retinoic acid can enhance the antitumor activity of non‐replicating Sendai virus particle against neuroblastoma
Authors: Nomura Motonari , Shimbo Takashi , Miyamoto Yasuhide , Fukuzawa Masahiro , Kaneda Yasufumi
Published: November 2012

Hemagglutinating virus of Japan‐envelope (HVJ‐E) is a drug delivery vector based on inactivated Sendai virus. Recently, antitumor activities were found for HVJ‐E itself and clinical trials of HVJ‐E for some malignant tumors are now ongoing. We investigated the in vitro and in vivo antitumor effects of HVJ‐E against neuroblastoma, which is one of the most common malignant solid tumors in childhood. The sensitivity of human neuroblastoma cell lines to HVJ‐E correlated with the expression level of gangliosides, Sialylparagloboside (SPG) and GD1a, receptors for HVJ. Among the cell lines, SK‐N‐SH was the most sensitive to HVJ‐E in vitro and total SPG and GD1a expression was the highest. Complete eradication of subcutaneous tumors derived from SK‐N‐SH cells was achieved by intratumoral injection of HVJ‐E in SCID mice and no recurrence was observed for more than 300 days after HVJ‐E inoculation. In contrast, NB1 cells expressed the lowest amount of GD1a and SPG and were resistant to HVJ‐E in vitro. The expression of GD1a increased by 13‐cis retinoic acid (13cRA), which is a therapeutic drug for high risk neuroblastoma, thus leading to an improved sensitivity to HVJ‐E in vitro. Only growth inhibition of the subcutaneous tumors derived from NB1 cells was achieved by HVJ‐E in the SCID mice, but the combination of 13cRA and HVJ‐E could achieve partial eradication of the xenograft and also lead to an improved prognosis. In conclusion, HVJ‐E is a promising therapeutic modality for neuroblastoma and 13cRA can be used as an adjuvant to HVJ‐E.
Hypercoagulability in Cushing's syndrome: prevalence, pathogenesis and treatment
Authors: van der Pas R. , Leebeek F.W.G. , Hofland L.J. , de Herder W.W. , Feelders R.A.
Published: November 2012

Cushing's syndrome is not only accompanied by an increased prevalence of cardiovascular disease but also by a hypercoagulable state that is reflected by an increased incidence of venous thromboembolism. Overall, patients with CS have been reported to have a more than 10‐fold increased risk of developing venous thromboembolism. Moreover, the incidence of postoperative thrombosis has been shown to be comparable to the risk after major orthopaedic surgery. Hypercoagulability in CS is due to both increased production of procoagulant factors with activation of the coagulation cascade and an impaired fibrinolytic capacity, resulting in a shortened activated partial thromboplastin time and an increased clot lysis time respectively.

Although these abnormalities seem to improve 1 year following successful surgery, they do not yet normalize. Therefore, sustained biochemical remission might be required to fully resolve the hypercoagulable state in CS.

Considering the risk of venous thromboembolism in uncontrolled CS there may be a rationale to give patients with active CS thromboprophylaxis. So far this seems warranted following surgical interventions. However, further studies are needed to determine the optimal dosage and duration of thromboprophylaxis.