bluuebunny/crossref_metadata_2025 huggingface dataset:
Holotomography versus X-ray grating interferometry: A comparative study
Authors: Zanette I. , Lang S. , Rack A. , Dominietto M. , Langer M. , Pfeiffer F. , Weitkamp T. , Müller B.
Published: December 2013

X-ray phase-contrast imaging techniques are used at synchrotron facilities to visualize tiny density variations in bulk samples. They overcome the limitations of other non-destructive methods, which often provide insufficient spatial and/or density resolution. Holotomography (HT) and X-ray grating interferometry (XGI) are among the most powerful phase-contrast techniques. Here, we show a direct comparison of HT versus XGI. We find that XGI excels in fidelity of the density measurements and is more robust against low-frequency artifacts, while HT is superior in spatial resolution. This study gives indications for applications and developments of phase-contrast imaging.
Thickness dependent exchange bias in martensitic epitaxial Ni-Mn-Sn thin films
Authors: Behler Anna , Teichert Niclas , Dutta Biswanath , Waske Anja , Hickel Tilmann , Auge Alexander , Hütten Andreas , Eckert Jürgen
Published: December 2013

A thickness dependent exchange bias in the low temperature martensitic state of epitaxial Ni-Mn-Sn thin films is found. The effect can be retained down to very small thicknesses. For a Ni50Mn32Sn18 thin film, which does not undergo a martensitic transformation, no exchange bias is observed. Our results suggest that a significant interplay between ferromagnetic and antiferromagnetic regions, which is the origin for exchange bias, is only present in the martensite. The finding is supported by ab initio calculations showing that the antiferromagnetic order is stabilized in the phase.
Weighing up the costs of seeking health care for dengue symptoms: a grounded theory study of backpackers’ decision-making processes
Authors: Vajta Bálint , Holberg Mette , Mills Jane , McBride William J. H.
Published: December 2013

Dengue fever, a mosquito-borne virus, is an ongoing public health issue in North Queensland. Importation of dengue fever by travellers visiting or returning to Australia can lead to epidemics. The mosquito can acquire the virus in the symptomatic viraemic phase, so timely recognition of cases is important to prevent epidemics. There is a gap in the literature about backpackers’ knowledge of dengue fever and the decision-making process they use when considering utilising the Australian health-care system. This study uses grounded theory methods to construct a theory that explains the process backpackers use when seeking health care. Fifty semi-structured interviews with backpackers, hostel receptionists, travel agents and pharmacists were analysed, resulting in identification of a core category: ‘weighing up the costs of seeking health care’. This core category has three subcategories: ‘self-assessment of health status’, ‘wait-and-see’ and ‘seek direction’. Findings from this study identified key areas where health promotion material and increased access to health-care professionals could reduce the risk of backpackers spreading dengue fever.
Influence of pathogenic bacteria species present in the postpartum bovine uterus on proteome profiles
Authors: Ledgard A. M. , Smolenski G. A. , Henderson H. , Lee R. S.-F.
Published: December 2013

In the first 2–3 weeks after parturition >90% of dairy cows will have some form of uterine infection. Uterine contamination with pathogens, such as Trueperella (formerly Arcanobacterium) pyogenes increases the risk of developing more severe endometritis, which can reduce conception rates. In this study, we compared the uterine proteome of cows infected with Trueperella pyogenes with that of uninfected cows, using 2D gel electrophoresis, and identified annexins A1 and A2 (ANXA1 and ANXA2), apolipoprotein A-1, calprotectin (S100A9), cathelicidin, enolase 1 (ENO1), peptidoglycan recognition protein 1 (PGLYRP1), phosphoglycerate mutase 1 (PGAM1), serine dehydratase (SDS) and serine protease inhibitors (SERPIN) B1, B3 and B4 proteins as differing in abundance in endometritis. Subsequently, levels of ten of these proteins were monitored in uterine samples collected from a herd of lactating, dairy cows at 15 and 42 days post-partum (DPP). The levels were compared with the cytology scores of the samples and the bacterial species isolated from the uterus. Cathelicidin, PGLYRP1, SERPINB1 and S100A9 levels at 15DPP showed strong positive correlations (r = 0.78, 0.80, 0.79, and 0.68 respectively; P < 0.001) with % of polymorphonuclear neutrophils (PMN). When compared with other bacterial pathogens identified, Streptococcus agalactiae and Truperella pyogenes induced increased expression of the indicator proteins, suggesting that these organisms may adversely affect the subsequent ability of the cow to conceive. Interestingly, there was no difference in the proportion of cows pregnant at 6 and 17 weeks after start of mating between the cows with high or low %PMN.
REVIEW: Aroma of Wheat Bread Crumb
Authors: Birch Anja Niehues , Petersen Mikael Agerlin , Hansen Åse Solvej
Published: December 2013

Bread aroma is an important parameter for bread quality, and this review aims to provide an overview of aroma compounds identified in bread crumb and how these compounds are formed. More than 150 volatile compounds were identified in bread crumb, and they mainly originated from the fermentative activity of yeast, from oxidation of flour lipids, and to a lower extent from Maillard reactions. Of those volatile compounds, 45 compounds can be characterized as aroma compounds, because they most likely can be sensed when the bread is eaten because of their high odor activity values and flavor dilution factors. The influence of ingredients and mixing conditions on bread aroma has scarcely been investigated. The fermentation conditions (yeast level and strain as well as fermentation temperature and time) were found to significantly influence the aroma of bread crumb. Yeast level and strain mainly influence formation of compounds directly related to the fermentative activity of yeast, whereas fermentation temperature and time also influence formation of compounds from oxidation of flour lipids.
Incubation of Isolated Wheat Starch with Proteolytic or Lipolytic Enzymes and Different Extraction Media Reveals a Tight Interaction Between Puroindolines and Lipids at Its Granule Surface
Authors: Pauly Anneleen , Pareyt Bram , De Brier Niels , Delcour Jan A.
Published: December 2013

Differences in hardness of wheat cultivars have been related to differences in interactions between the starch granule surface and the gluten protein matrix that are mediated by the proteins puroindoline (PIN) A and B. We examined whether or not PINs and (polar) lipids are associated at the starch granule surface, and, if so, how they interact with the starch granule surface itself. Starch was isolated from a soft wheat cultivar containing both wild‐type PINs and incubated with peptidases or lipases, or in extraction media (typically used for defatting). Protein, PIN, and lipid levels revealed that PINs and lipids are tightly associated together at the starch granule surface. Our results imply that PINs need lipids for binding to the granule surface but not vice versa.
Herbivore Cues from the Fall Armyworm (Spodoptera frugiperda) Larvae Trigger Direct Defenses in Maize
Authors: Chuang Wen-Po , Ray Swayamjit , Acevedo Flor Edith , Peiffer Michelle , Felton Gary W. , Luthe Dawn S.
Published: December 2013

In addition to feeding damage, herbivores release cues that are recognized by plants to elicit defenses. Caterpillar oral secretions have been shown to trigger herbivore defense responses in several different plant species. In this study, the effects of two fall armyworm (Spodoptera frugiperda) oral secretions (saliva and regurgitant) on caterpillar defense responses in maize (Zea mays) were examined. Only minute amounts of regurgitant were deposited on the maize leaf during larval feeding bouts and its application to leaves failed to induce the expression of several herbivore defense genes. On the other hand, caterpillars consistently deposited saliva on leaves during feeding and the expression of several maize defense genes significantly increased in response to saliva application and larval feeding. However, feeding by ablated caterpillars with impaired salivation did not induce these defenses. Furthermore, bioassays indicated that feeding by unablated caterpillars significantly enhanced defenses when compared with that of ablated caterpillars. Another critical finding was that the maize genotype and stage of development affected the expression of defense genes in response to wounding and regurgitant treatments. These results demonstrate that fall armyworm saliva contains elicitors that trigger herbivore defenses in maize.
Substitutions of Two Amino Acids in the Nucleotide-Binding Site Domain of a Resistance Protein Enhance the Hypersensitive Response and Enlarge the PM3F Resistance Spectrum in Wheat
Authors: Stirnweis Daniel , Milani Samira Désiré , Jordan Tina , Keller Beat , Brunner Susanne
Published: December 2013

Proteins with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains are major components of the plant immune system. They usually mediate resistance against a subgroup of races of a specific pathogen. For the allelic series of the wheat powdery mildew resistance gene Pm3, alleles with a broad and a narrow resistance spectrum have been described. Here, we show that a broad Pm3 spectrum range correlates with a fast and intense hypersensitive response (HR) in a Nicotiana transient-expression system and this activity can be attributed to two particular amino acids in the ARC2 subdomain of the NBS. The combined substitution of these amino acids in narrow-spectrum PM3 proteins enhances their capacity to induce an HR in Nicotiana benthamiana, and we demonstrate that these substitutions also enlarge the resistance spectrum of the Pm3f allele in wheat. Finally, using Bph14, we show that the region carrying the relevant amino acids also plays a role in the HR regulation of another coiled-coil NBS-LRR resistance protein. These results highlight the importance of an optimized NBS-‘molecular switch’ for the conversion of initial pathogen perception by the LRR into resistance-protein activation, and we describe a possible approach to extend the effectiveness of resistance genes via minimal targeted modifications in the NBS domain.
PythiumSpecies and Isolate Diversity Influence Inhibition by the Biological Control AgentStreptomyces lydicus
Authors: Weiland Jerry E.
Published: December 2013

Disease control of soilborne pathogens by biological control agents (BCAs) is often inconsistent under field conditions. This inconsistency may be partly influenced by pathogen diversity if there is a differential response among pathogen species and isolates to selected BCAs. The responses of 148 Pythium isolates obtained from soil at three forest nurseries and representative of 16 Pythium spp. were evaluated in the presence of Streptomyces lydicus strain WYEC108 in an in vitro assay. Percent growth inhibition, inhibition zone distance, mortality, and growth rate were recorded for each isolate, and data were analyzed for effects of species and isolate. Responses of three Pythium spp. (Pythium irregulare, P. sylvaticum, and P. ultimum) were further analyzed for a location (nursery) effect. Although S. lydicus inhibited all Pythium isolates, differences in percent growth inhibition, inhibition zone distance, and mortality were observed among Pythium spp. and isolates. Small but significant location effects were also noted. Growth rate also varied among Pythium spp. and isolates and was found to strongly bias percent growth inhibition and, to a lesser degree, inhibition zone distance; depending on which measure was used, slower-growing isolates appeared less sensitive (growth inhibition) or more sensitive (inhibition zone) to S. lydicus than faster-growing isolates. Results illustrate the importance of using multiple, representative pathogen isolates in preliminary BCA inhibition assays as well as accounting for the effect of pathogen growth rate on pathogen inhibition by BCAs. Future studies should take pathogen diversity into account when evaluating biological control efficacy.
Relationships Between Airborne Pseudoperonospora cubensis Sporangia, Environmental Conditions, and Cucumber Downy Mildew Severity
Authors: Granke L. L. , Morrice J. J. , Hausbeck M. K.
Published: December 2013

Airborne Pseudoperonospora cubensis sporangia were collected 0.5 m above the ground from May to late September or early October 2010 and 2011 in unsprayed cucumber (Cucumis sativus) fields in Benton Harbor and Frankenmuth, MI. Cucumber downy mildew incidence and severity were evaluated weekly within each field from June until September or October. The first airborne sporangium was detected before the crop was planted for each site-year. The greatest numbers of airborne sporangia were detected when moderate to high disease severity (≥5% symptomatic leaf area) was detected within the field. Fewer airborne sporangia were present with low disease severity (<5% symptomatic leaf area), and even fewer were detected prior to planting the cucumber crop. The number of airborne sporangia detected, time post planting, planting number (first versus second versus third planting), temperature, and leaf wetness were positively associated and solar radiation was negatively associated with disease occurrence for at least one site-year. Michigan growers currently use an aggressive, calendar-based fungicide program to manage cucumber downy mildew. Because airborne sporangium concentrations were one of the most important factors identified in this study, the current fungicide recommendation of decreasing the spray interval following disease detection in an area is warranted.
Phylogeny of the GenusSynchytriumand the Development of TaqMan PCR Assay for Sensitive Detection ofSynchytrium endobioticumin Soil
Authors: Smith Donna S. , Rocheleau Hélène , Chapados Julie T. , Abbott Cathryn , Ribero Sharon , Redhead Scott A. , Lévesque C. André , De Boer Solke H.
Published: December 2013

Potato wart, caused by the fungal pathogen Synchytrium endobioticum, is a serious disease with the potential to cause significant economic damage. The small subunit (SSU) and internal transcribed spacer (ITS) ribosomal DNA (rDNA) were sequenced for several Synchytrium spp., showing a high rate of variability for both of these markers among the different species and monophyly of the genus within phylum Chytridiomycota. The intergenic nontranscribed spacer (IGS) of rDNA was sequenced for different pathotypes and showed no intraspecific variation within S. endobioticum, similar to the other rDNA markers from this study. To facilitate screening for the pathogen in soil, three TaqMan polymerase chain reaction (PCR) assays were developed from SSU, ITS, and IGS rDNA sequences to detect S. endobioticum sporangia in the chloroform-flotation fraction of sieved soil extracts. In the screening portion of the method, a first TaqMan assay targeting the SSU rDNA was developed with positive results that were further confirmed with amplicon melt analysis. A synthetic reaction control cloned into a plasmid was incorporated into the procedure, facilitating the validation of negative results. The presence of the reaction control did not adversely affect the efficiency of the SSU target amplification. A second TaqMan assay targeting the ITS-1 region was developed as a confirmatory test. There was 100% accordance between the SSU and ITS-1 TaqMan assays. Utilizing these two assays in tandem achieved good specificity for S. endobioticum, generating negative results with the cloned SSU and ITS-1 regions from all 14 other Synchytrium spp. considered. Spike recovery experiments indicated that these assays, targeting the SSU and ITS-1 rDNA regions, developed from a phylogeny dataset of the genus, could reliably detect a single sporangium in the chloroform flotation fraction of a soil extract. Good correlation between microscopic detection of sporangia and PCR results in both positive and negative soil samples was dually demonstrated for both the SSU and ITS-1 assays.
Characterization by Deep Sequencing of Divergent Plum bark necrosis stem pitting-associated virus (PBNSPaV) Isolates and Development of a Broad-Spectrum PBNSPaV Detection Assay
Authors: Marais Armelle , Faure Chantal , Couture Carole , Bergey Bernard , Gentit Pascal , Candresse Thierry
Published: December 2013

Plum bark necrosis stem pitting-associated virus (PBNSPaV), the causal agent of plum bark necrosis stem pitting disease, belongs to the genus Ampelovirus in the family Closteroviridae. The complete genome sequence of PBNSPaV isolates from four Prunus sources was determined by pyrosequencing. All isolates showed the same genomic organization as the PBNSPaV reference isolate. The least divergent isolate, found in a peach tree from China, showed an overall 91.8% of nucleotide identity with the type isolate. Two closely related isolates, defining a second cluster of diversity, were found in two Japanese plum lines from France and showed only 82.8% identity with the type isolate. On the other hand, they were highly homologous with two recently described PBNSPaV divergent isolates from China. The fourth and most divergent isolate, from a Chinese peach, showed only 71.2% identity to other PBNSPaV isolates and was not detected by currently available PBNSPaV reverse-transcription polymerase chain reaction detection assays. Complete sequencing of the divergent isolates allowed the development of a more broad-spectrum detection test targeting a conserved region in the P61 gene. Taken together, these results indicate a much broader diversity of PBNSPaV than previously thought and provide for a more robust detection of this still poorly characterized pathogen.
Induction of Salicylic Acid–Mediated Defense Response in Perennial Ryegrass Against Infection by Magnaporthe oryzae
Authors: Rahman Alamgir , Kuldau Gretchen A. , Uddin Wakar
Published: December 2013

Incorporation of plant defense activators is an innovative approach to development of an integrated strategy for the management of turfgrass diseases. The effects of salicylic acid (SA), benzothiadiazole (BTH, chemical analog of SA), jasmonic acid (JA), and ethephon (ET, an ethylene-releasing compound) on development of gray leaf spot in perennial ryegrass (Lolium perenne L.) caused by Magnaporthe oryzae were evaluated. Gray leaf spot disease incidence and severity were significantly decreased when plants were treated prior to inoculation with SA, BTH, and partially by ET but not by JA. Accumulation of endogenous SA and elevated expression of pathogenesis-related (PR)-1, PR-3.1, and PR-5 genes were associated with inoculation of plants by M. oryzae. Treatment of plants with SA enhanced expression levels of PR-3.1 and PR-5 but did not affect the PR-1 level, whereas BTH treatment enhanced relative expression levels of all three PR genes. Microscopic observations of leaves inoculated with M. oryzae revealed higher frequencies of callose deposition at the penetration sites in SA- and BTH-treated plants compared with the control plants (treated with water). These results suggest that early and higher induction of these genes by systemic resistance inducers may provide perennial ryegrass with a substantial advantage to defend against infection by M. oryzae.
Incidence of Dysphagia and Serial Videofluoroscopic Swallow Study Findings After Anterior Cervical Discectomy and Fusion
Authors: Min Yusun , Kim Won-Seok , Kang Sung Shik , Choi Jin Man , Yeom Jin S. , Paik Nam-Jong
Published: December 2013

Study Design:

Prospective study.

Objective:

To prospectively assess the incidence of dysphagia and to present the serial changes of each finding in the videofluoroscopic swallow study (VFSS) after anterior cervical discectomy and fusion (ACDF).

Summary of Background Data:

The reported incidence of dysphagia after ACDF has varied widely, and the serial changes of dysphagia using VFSS have not been clearly determined yet.

Methods:

Data of 47 patients preoperatively and at 1 week and 1 month postoperatively were used for the analyses. The Bazaz dysphagia score and VFSS were checked preoperatively and at 1 week and 1 month postoperatively. The presence of aspiration or penetration, amount of vallecular and pyriform sinus residues, functional dysphagia scale, temporal parameters of oral transit time, pharyngeal transit time, and pharyngeal delay time (PDT) were evaluated from the VFSS data.

Results:

Incidences of dysphagia measured by the Bazaz dysphagia score were 83.0% at 1 week and 59.6% at 1 month after ACDF. Although the incidence of aspiration was 4.3% and the incidence of penetration was 36.2% at 1 week and 25.5% at 1 month after surgery, none of the patients had aspiration pneumonia. The number of patients with vallecular and pyriform sinus residues significantly increased after ACDF. Further, there were no statistically significant changes at all time points in terms of oral transit time, pharyngeal transit time, and pharyngeal delay time.

Conclusions:

Dysphagia is common until 1 month after ACDF. Although the incidence of aspiration or penetration in VFSS after ACDF was high, no patient had aspiration pneumonia, which may be because of the intact neurological swallowing mechanism. The typical pattern of dysphagia after ACDF included vallecular and pyriform sinuses filled with postswallow residue, which may result from soft tissue edema and weak constriction of pharyngeal muscles after ACDF.
Vision-based flight control in the hawkmothHyles lineata
Authors: Windsor Shane P. , Bomphrey Richard J. , Taylor Graham K.
Published: December 2013

Vision is a key sensory modality for flying insects, playing an important role in guidance, navigation and control. Here, we use a virtual-reality flight simulator to measure the optomotor responses of the hawkmothHyles lineata, and use a published linear-time invariant model of the flight dynamics to interpret the function of the measured responses in flight stabilization and control. We recorded the forces and moments produced during oscillation of the visual field in roll, pitch and yaw, varying the temporal frequency, amplitude or spatial frequency of the stimulus. The moths’ responses were strongly dependent upon contrast frequency, as expected if the optomotor system uses correlation-type motion detectors to sense self-motion. The flight dynamics model predicts that roll angle feedback is needed to stabilize the lateral dynamics, and that a combination of pitch angle and pitch rate feedback is most effective in stabilizing the longitudinal dynamics. The moths’ responses to roll and pitch stimuli coincided qualitatively with these functional predictions. The moths produced coupled roll and yaw moments in response to yaw stimuli, which could help to reduce the energetic cost of correcting heading. Our results emphasize the close relationship between physics and physiology in the stabilization of insect flight.
Calcium waves initiating from the anomalous subdiffusive calcium sparks
Authors: Chen Xi , Guo Liang , Kang Jianhong , Huo Yunlong , Wang Shiqiang , Tan Wenchang
Published: December 2013

The objective of the study is to investigate the propagation of Ca
2+
waves in full-width cardiac myocytes and carry out sensitivity analysis to study the effects of various physiological parameters on global Ca
2+
waves. Based on the anomalous subdiffusion of Ca
2+
sparks, a mathematical model was proposed to characterize the Ca
2+
waves. The computed results were in agreement with the experimental measurements using confocal microscopy. This model includes variables of current through the Ca
2+
release unit (CRU;
I
CRU
), duration of current flow through CRU (
T
open
), Ca
2+
sensitivity parameter (
K
), the longitudinal and transverse spatial separation of CRUs (

l
x

and

l
y

, where
x
denotes longitudinal direction (
x
-axis) and
y
denotes transverse direction (
y
-axis)) and Ca
2+
diffusion coefficients (

D
x

,

D
y

). The spatio-temporal mechanism of the anomalous Ca
2+
sparks led to results that were different from those based on Fick's law. The major findings were reported as:
I
CRU
affected the dynamic properties of Ca
2+
waves more significantly than
T
open
; the effect of
K
on the properties of Ca
2+
waves was negligible;

l
y

affected the amplitude significantly, but

l
x

affected the longitudinal velocity significantly; in turn, the limitation and significance of the study are discussed.
An automatic service for the personalization of ventricular cardiac meshes
Authors: Lamata Pablo , Sinclair Matthew , Kerfoot Eric , Lee Angela , Crozier Andrew , Blazevic Bojan , Land Sander , Lewandowski Adam J. , Barber David , Niederer Steve , Smith Nic
Published: December 2013

Computational cardiac physiology has great potential to improve the management of cardiovascular diseases. One of the main bottlenecks in this field is the customization of the computational model to the anatomical and physiological status of the patient. We present a fully automatic service for the geometrical personalization of cardiac ventricular meshes with high-order interpolation from segmented images. The method is versatile (able to work with different species and disease conditions) and robust (fully automatic results fulfilling accuracy and quality requirements in 87% of 255 cases). Results also illustrate the capability to minimize the impact of segmentation errors, to overcome the sparse resolution of dynamic studies and to remove the sometimes unnecessary anatomical detail of papillary and trabecular structures. The smooth meshes produced can be used to simulate cardiac function, and in particular mechanics, or can be used as diagnostic descriptors of anatomical shape by cardiologists. This fully automatic service is deployed in a cloud infrastructure, and has been made available and accessible to the scientific community.
John Lubbock, science, and the liberal intellectual
Authors: Clark J. F. M.
Published: December 2013

John Lubbock's longest-standing scientific research interest was entomology. Some of his earliest systematic investigations of insect and marine life began under the tutelage of Darwin. Darwin shaped the trajectory of, and the programme for, Lubbock's natural history work. However, to understand John Lubbock's identity as a scientist, he must be located within the context of the Victorian ‘intellectual’. This paper traces Lubbock's entomological work from its early development under Darwin to his later work on insect sensory physiology and comparative psychology. Far from being the death of his scientific career, Lubbock's entry into Parliament marked the pinnacle of his career as a scientific intellectual. He built on his early work on invertebrate anatomy, physiology and taxonomy, and on his archaeological and anthropological research to expound his vision of mental evolution. His research on ‘savages’, on ants, bees and wasps, and on his dog, ‘Van’, permitted him to expatiate upon the psychic unity of all sentient beings, which, in turn, underpinned his overarching educational programme.
Exactification of the Poincaré asymptotic expansion of the Hankel integral: spectacularly accurate asymptotic expansions and non-asymptotic scales
Authors: Galapon Eric A. , Martinez Kay Marie L.
Published: December 2013

We obtain an exactification of the Poincaré asymptotic expansion (PAE) of the Hankel integral,as, using the distributional approach of McClure & Wong. We find that, for half-integer orders of the Bessel function, the exactified asymptotic series terminates, so that it gives an exact finite sum representation of the Hankel integral. For other orders, the asymptotic series does not terminate and is generally divergent, but is amenable to superasymptotic summation, i.e. by optimal truncation. For specific examples, we compare the accuracy of the optimally truncated asymptotic series owing to the McClure–Wong distributional method with owing to the Mellin–Barnes integral method. We find that the former is spectacularly more accurate than the latter, by, in some cases, more than 70 orders of magnitude for the same moderate value ofb. Moreover, the exactification can lead to a resummation of the PAE when it is exact, with the resummed Poincaré series exhibiting again the same spectacular accuracy. More importantly, the distributional method may yield meaningful resummations that involve scales that are not asymptotic sequences.
Number and twistedness of strands in weavings on regular convex polyhedra
Authors: Kovács F.
Published: December 2013

This paper deals with two- and threefold weavings on Platonic polyhedral surfaces. Depending on the skewness of the weaving pattern with respect to the edges of the polyhedra, different numbers of closed strands are necessary in a complete weaving. The problem is present in basketry but can be addressed from the aspect of pure geometry (geodesics), graph theory (central circuits of 4-valent graphs) and even structural engineering (fastenings on a closed surface). Numbers of these strands are found to have a periodicity and symmetry, and, in some cases, this number can be predicted directly from the skewness of weaving. In this paper (i) a simple recursive method using symmetry operations is given to find the number of strands of cubic, octahedral and icosahedral weavings for cases where generic symmetry arguments fail; (ii) another simple method is presented to decide whether or not a single closed strand can run along the underlying Platonic without a turn (i.e. the linking number of the two edges of a strand is zero, and so the loop can be stretched to a circle without being twisted); and (iii) the linking number of individual strands in an alternate ‘check’ weaving pattern is determined.
Can Bohmian mechanics be made relativistic?
Authors: Dürr Detlef , Goldstein Sheldon , Norsen Travis , Struyve Ward , Zanghì Nino
Published: December 2013

In relativistic space–time, Bohmian theories can be formulated by introducing a privileged foliation of space–time. The introduction of such a foliation—as extra absolute space–time structure—would seem to imply a clear violation of Lorentz invariance, and thus a conflict with fundamental relativity. Here, we consider the possibility that, instead of positing it as extra structure, the required foliation could be covariantly determined by the wave function. We argue that this allows for the formulation of Bohmian theories that seem to qualify as fundamentally Lorentz invariant. We conclude with some discussion of whether or not they might also qualify as fundamentally relativistic.
Characterizing behavioural ‘characters’: an evolutionary framework
Authors: Araya-Ajoy Yimen G. , Dingemanse Niels J.
Published: December 2013

Biologists often study phenotypic evolution assuming that phenotypes consist of a set of quasi-independent units that have been shaped by selection to accomplish a particular function. In the evolutionary literature, such quasi-independent functional units are called ‘evolutionary characters’, and a framework based on evolutionary principles has been developed to characterize them. This framework mainly focuses on ‘fixed’ characters, i.e. those that vary exclusively between individuals. In this paper, we introduce multi-level variation and thereby expand the framework to labile characters, focusing on behaviour as a worked example. We first propose a concept of ‘behavioural characters’ based on the original evolutionary character concept. We then detail how integration of variation between individuals (cf. ‘personality’) and within individuals (cf. ‘individual plasticity’) into the framework gives rise to a whole suite of novel testable predictions about the evolutionary character concept. We further propose a corresponding statistical methodology to test whether observed behaviours should be considered expressions of a hypothesized evolutionary character. We illustrate the application of our framework by characterizing the behavioural character ‘aggressiveness’ in wild great tits,Parus major.
Aerodynamic characteristics of a feathered dinosaur measured using physical models. Effects of form on static stability and control effectiveness.
Authors: Evangelista Dennis , Cardona Griselda , Guenther-Gleason Eric , Huynh Tony , Kwong Austin , Marks Dylan , Ray Neil , Tisbe Adrian , Tse Kyle , Kohl Mimi
Published: December 2013

We report the effects of posture and morphology on the static aerodynamic stability and control effectiveness of physical models based on the feathered dinosaur,Microraptor gui, from the Cretaceous of China. Postures had similar lift and drag coefficients and were broadly similar when simplified metrics of gliding were considered, but they exhibited different stability characteristics depending on the position of the legs and the presence of feathers on the legs and the tail. Both stability and the function of appendages in generating maneuvering forces and torques changed as the glide angle or angle of attack were changed. These are significant because they represent an aerial environment that may have shifted during the evolution of directed aerial descent and other aerial behaviors. Certain movements were particularly effective (symmetric movements of the wings and tail in pitch, asymmetric wing movements, some tail movements). Other appendages altered their function from creating yaws at high angle of attack to rolls at low angle of attack, or reversed their function entirely. WhileM. guilived afterArchaeopteryxand likely represents a side experiment with feathered morphology, the general patterns of stability and control effectiveness suggested from the manipulations of forelimb, hindlimb and tail morphology here may help understand the evolution of flight control aerodynamics in vertebrates. Though these results rest on a single specimen, as further fossils with different morphologies tested, the findings here could be applied in a phylogenetic context to reveal biomechanical constraints on extinct flyers arising from the need to maneuver. Now published in PLOS ONE http://dx.plos.org/10.1371/journal.pone.0085203
Effect of glycogen synthase kinase-3 inactivation on mouse mammary gland development and oncogenesis
Authors: Dembowy Joanna , Adissu Hibret A. , Liu Jeff C. , Zacksenhaus Eldad , Woodgett James R.
Published: December 2013

Many components of Wnt/β-catenin signaling pathway have critical functions in mammary gland development and tumor formation, yet the contribution of glycogen synthase kinase-3 (GSK-3α and GSK-3β) to mammopoiesis and oncogenesis is unclear. Here, we report that WAP-Cre-mediated deletion of GSK-3 in the mammary epithelium results in activation of Wnt/β-catenin signaling and induces mammary intraepithelial neoplasia that progresses to squamous transdifferentiation and development of adenosquamous carcinomas at 6 months. To uncover possible β-catenin-independent activities of GSK-3, we generated mammary-specific knock-outs of GSK-3 and β-catenin. Squamous transdifferentiation of the mammary epithelium was largely attenuated, however mammary epithelial cells lost the ability to form mammospheres suggesting perturbation of stem cell properties unrelated to loss of β-catenin alone. At 10 months, adenocarcinomas that developed in glands lacking GSK-3 and β-catenin displayed elevated levels of γ-catenin/plakoglobin as well as activation of the Hedgehog and Notch pathways. Collectively these results establish the two isoforms of GSK-3 as essential integrators of multiple developmental signals that act to maintain normal mammary gland function and suppress tumorigenesis.
Determinants of root‐associated fungal communities within Asteraceae in a semi‐arid grassland
Authors: Wehner Jeannine , Powell Jeff R. , Muller Ludo A. H. , Caruso Tancredi , Veresoglou Stavros D. , Hempel Stefan , Rillig Matthias C.
Published: December 2013

While plant–fungal interactions are important determinants of plant community assembly and ecosystem functioning, the processes underlying fungal community composition are poorly understood.

Here, we studied for the first time the root‐associated eumycotan communities in a set of co‐occurring plant species of varying relatedness in a species‐rich, semi‐arid grassland in Germany. The study system provides an opportunity to evaluate the importance of host plants and gradients in soil type and landscape structure as drivers of fungal community structure on a relevant spatial scale. We used 454 pyrosequencing of the fungal internal transcribed spacer region to analyse root‐associated eumycotan communities of 25 species within the Asteraceae, which were sampled at different locations within a soil type gradient. We partitioned the variance accounted for by three predictors (host plant phylogeny, spatial distribution and soil type) to quantify their relative roles in determining fungal community composition and used null model analyses to determine whether community composition was influenced by biotic interactions among the fungi.

We found a high fungal diversity (156 816 sequences clustered in 1100 operational taxonomic units (OTUs)). Most OTUs belonged to the phylum Ascomycota (35.8%); the most abundant phylotype best‐matched Phialophora mustea. Basidiomycota were represented by 18.3%, with Sebacina as most abundant genus. The three predictors explained 30% of variation in the community structure of root‐associated fungi, with host plant phylogeny being the most important variance component. Null model analysis suggested that many fungal taxa co‐occurred less often than expected by chance, which demonstrates spatial segregation and indicates that negative interactions may prevail in the assembly of fungal communities.

Synthesis. The results show that the phylogenetic relationship of host plants is the most important predictor of root‐associated fungal community assembly, indicating that fungal colonization of host plants might be facilitated by certain plant traits that may be shared among closely related plant species.
Investigating the experiences in a school‐based occupational therapy program to inform community‐based paediatric occupational therapy practice
Authors: Rens Lezahn , Joosten Annette
Published: December 2013

Background/aim

A collaborative approach with teachers is required when providing community‐based occupational therapy to educationally at risk children. Collaborators share common goals and interact and support each other but challenges arise in providing collaborative occupational therapy in settings outside the school environment. The aim of this study was to capture experiences of teachers and occupational therapists working within a school‐based occupational therapy program to determine if their experiences could inform collaborative practice.

Method

In this pilot study, participant responses to questionnaires (n = 32) about their experiences formed the basis for focus groups and individual interviews. Two focus group were conducted, one with teachers (n = 11) and one with occupational therapy participants (n = 6). Individual interviews were conducted with the supervising occupational therapist, school principal and two leading teachers. Descriptive statistics were used to analyse the data from closed questions, and thematic analysis using a constant comparison approach was used to analyse open ended questions, focus groups and interviews.

Results

Three main themes emerged: (i) the need for occupational therapists to spend time in the school, to explain their role, build relationships, understand classroom routines and the teacher role; (ii) occupational therapists need to not see themselves as the expert but develop equal partnerships to set collaborative goals and (iii) occupational therapists advocating for all parties to be informed throughout the occupational therapy process.

Conclusion

The pilot study findings identified teacher and therapist experiences within the school setting that could inform improved collaborative practice with teachers and community‐based occupational therapists and these findings warrant further investigation.
Living tensions: Reconstructing notions of professionalism in occupational therapy
Authors: Mackey Hazel
Published: December 2013

Background/aim

Reform of health organisations has brought significant changes to healthcare systems with attendant consequences for the definition and practice of professionalism. Occupational therapists must continually strive to provide excellent patient care, delivering positive patient outcomes whilst responding effectively to increasing fiscal constraint and changing organisational paradigms. This paper explores the experiences of occupational therapists as they reconstruct professionalism as a consequence of health care reform inEngland.

Method

Fourteen occupational therapists were interviewed over 12 months across five National Health Service organisations in England. Each participant was interviewed three times and was asked to keep a monthly diary of critical incidents. A process of narrative analysis was developed to analyse these data.

Results

Findings suggest that changes have occurred in the National Health Service which affects notions of professional values, expertise, status and accountability. However, far from seeing themselves as mere responders to stimuli, occupational therapists tell of mediating policies, of responding, experimenting and redefining choices whilst struggling to reconstruct professionalism.

Conclusions

It is suggested that professionalism can be conceived as a reflexive ethical concept in that it is through the process of reflecting on the discursive and behavioural options and values available that occupational therapists come to understand, and define their professional selves.
Investigating Flavonoids as Molecular Templates for the Design of Small‐Molecule Inhibitors of Cell Signaling
Authors: Wright Bernice , Tindall Marcus J. , Lovegrove Julie A. , Gibbins Jonathan M.
Published: December 2013

Epidemiological and clinical trials reveal compelling evidence for the ability of dietary flavonoids to lower cardiovascular disease risk. The mechanisms of action of these polyphenolic compounds are diverse, and of particular interest is their ability to function as protein and lipid kinase inhibitors. We have previously described structure–activity studies that reinforce the possibility for using flavonoid structures as templates for drug design. In the present study, we aim to begin constructing rational screening strategies for exploiting these compounds as templates for the design of clinically relevant, antiplatelet agents. We used the platelet as a model system to dissect the structural influence of flavonoids, stilbenes, anthocyanidins, and phenolic acids on inhibition of cell signaling and function. Functional groups identified as relevant for potent inhibition of platelet function included at least 2 benzene rings, a hydroxylated B ring, a planar C ring, a C ring ketone group, and a C‐2 positioned B ring. Hydroxylation of the B ring with either a catechol group or a single C‐4′ hydroxyl may be required for efficient inhibition of collagen‐stimulated tyrosine phosphorylated proteins of 125 to 130 kDa, but may not be necessary for that of phosphotyrosine proteins at approximately 29 kDa. The removal of the C ring C‐3 hydroxyl together with a hydroxylated B ring (apigenin) may confer selectivity for 37 to 38 kDa phosphotyrosine proteins. We conclude that this study may form the basis for construction of maps of flavonoid inhibitory activity on kinase targets that may allow a multitargeted therapeutic approach with analogue counterparts and parent compounds.
Broad Escovopsis‐inhibition activity of Pseudonocardia associated with Trachymyrmex ants
Authors: Meirelles Lucas A. , Mendes Thaís D. , Solomon Scott E. , Bueno Odair C. , Pagnocca Fernando C. , Rodrigues Andre
Published: December 2013

Attine ants maintain an association with antibiotic‐producing Actinobacteria found on their integuments. Evidence supports these bacteria as auxiliary symbionts that help ants to defend the fungus gardens against pathogens. Using Pseudonocardia strains isolated from Trachymyrmex ants, we tested whether the inhibitory capabilities of such strains are restricted to Escovopsis parasites that infect gardens of this ant genus. Twelve Pseudonocardia strains were tested in in vitro bioassays against Escovopsis strains derived from fungus gardens of Trachymyrmex (n = 1) and leaf‐cutting ants (n = 3). Overall, significant differences were observed in the mycelial growth among each Escovopsis strain in the presence of Pseudonocardia. Particularly, Escovopsis from Acromyrmex and Trachymyrmex were the most inhibited strains in comparison to Escovopsis isolated from Atta. This result suggests that Pseudonocardia isolated from Trachymyrmex possibly secrete antimicrobial compounds effective against diverse Escovopsis strains. The fact that Trachymyrmex ants harbour Pseudonocardia strains with broad spectrum of activity and its defensive role on attine gardens are discussed.
Initial reactions to tobacco and cannabis smoking: a twin study
Authors: Agrawal Arpana , Madden Pamela A. F. , Bucholz Kathleen K. , Heath Andrew C. , Lynskey Michael T.
Published: December 2013

Background and Aims

Initial subjective reactions to cannabis and tobacco, broadly classified as positive or negative, have previously been explored for their associations with onset and maintenance of subsequent abuse/dependence. We examine (i) the factorial architecture of self‐reported initial reactions to cannabis and tobacco; (ii) whether these factors associate with concurrently reported age at onset of DSM‐IV diagnosis of nicotine dependence and cannabis abuse/dependence; and (iii) estimate heritable variation in and covariation between the factors.

Design

Factorial and exploratory structural equation modeling was conducted to examine the factor structure of initial reactions. Cox proportional hazards modeling was employed to examine their association with time to onset of diagnosis of DSM‐IV nicotine dependence and cannabis abuse/dependence. Classical twin modeling, using univariate and multivariate models, was used to parse variance in each factor (and the covariance between factors) to their additive genetic, shared environmental and non‐shared environmental sources.

Setting and Participants

General population sample of Caucasian female twins aged 18–32 years, with a life‐time history of tobacco [n = 2393] and cannabis [n = 1445] use.

Measurement

Self‐report of initial subjective reactions to tobacco (cigarettes) and cannabis the first time they were used and time to onset of life‐time history of DSM‐IV diagnosis of abuse (cannabis) and dependence (cannabis or nicotine).

Findings

Factors representing putatively positive and negative reactions to cannabis and tobacco emerged. Initial reactions to tobacco were associated with onset of DSM‐IV diagnosis of nicotine dependence and cannabis abuse/dependence while initial reactions to cannabis were associated with onset of DSM‐IV diagnosis of cannabis abuse/dependence alone. Genetic factors played a moderate role in each factor (heritability of 27–35%, P < 0.05), with the remaining variance attributed to individual–specific environment. Covariation across the factors indexing positive and negative initial reactions was attributable to genetic sources (0.18–0.58, P < 0.05) and to overlapping individual‐specific environmental factors (−0.16 to 0.36, P < 0.05).

Conclusions

Initial subjective reactions to tobacco are associated with onset of DSM‐IV diagnosis of nicotine dependence and cannabis abuse/dependence while initial subjective reactions to cannabis are only associated with onset of diagnosis of DSM‐IV cannabis abuse/dependence. Genetic and environmental factors underpin the overlap across the factors representing initial reactions, both positive and negative.