bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrostatic Korteweg-deVries solitary waves in a plasma with Kappa-distributed electrons
Authors: Choi C.-R. , Min K.-W. , Rhee T.-N.
Published: September 2011

The Korteweg-deVries (KdV) equation that describes the evolution of nonlinear ion-acoustic solitary waves in plasmas with Kappa-distributed electrons is derived by using a reductive perturbation method in the small amplitude limit. We identified a dip-type (negative) electrostatic KdV solitary wave, in addition to the hump-type solution reported previously. The two types of solitary waves occupy different domains on the κ (Kappa index)-V (propagation velocity) plane, separated by a curve corresponding to singular solutions with infinite amplitudes. For a given Kappa value, the dip-type solitary wave propagates faster than the hump-type. It was also found that the hump-type solitary waves cannot propagate faster than V = 1.32.
Chaotic solitons in the quadratic-cubic nonlinear Schrödinger equation under nonlinearity management
Authors: Fujioka J. , Cortés E. , Pérez-Pascual R. , Rodríguez R. F. , Espinosa A. , Malomed B. A.
Published: September 2011

We analyze the response of rational and regular (hyperbolic-secant) soliton solutions of an extended nonlinear Schrödinger equation (NLSE) which includes an additional self-defocusing quadratic term, to periodic modulations of the coefficient in front of this term. Using the variational approximation (VA) with rational and hyperbolic trial functions, we transform this NLSE into Hamiltonian dynamical systems which give rise to chaotic solutions. The presence of chaos in the variational solutions is corroborated by calculating their power spectra and the correlation dimension of the Poincaré maps. This chaotic behavior (predicted by the VA) is not observed in the direct numerical solutions of the NLSE when rational initial conditions are used. The solitary-wave solutions generated by these initial conditions gradually decay under the action of the nonlinearity management. On the contrary, the solutions of the NLSE with exponentially localized initial conditions are robust solitary-waves with oscillations consistent with a chaotic or a complex quasiperiodic behavior.
A comparison between the permittivity and electric modulus representations of the microwave response of carbon black loaded polymer composites under uniaxial tension
Authors: Belattar J. , Achour M. E. , Brosseau C.
Published: September 2011

In this work, the relaxation dynamics (RD) in carbon black (CB)-polymer composites under stress is investigated by two complementary approaches: effective permittivity and electric modulus formally defined as the reciprocal of the complex relative permittivity. Experimental measurements of the microwave data over the of CB volume fractions below the percolation threshold and microwave frequencies studied agree well with the predictions of the Cole-Cole (CC) phenomenological model of RD. Similar conclusions about the RD of subpercolative samples could be reached by viewing the data in terms of their ɛ and M representations. For subpercolative systems, the CB aggregates show nearly no influence on the dielectric relaxation through the matrix. However, we show that the relaxation time scale is increased by two orders of magnitude when CB volume fraction is increased from below to above the percolation threshold at about 8.5 vol%. Extraction of the RD information from CC modeling shows that when the system is subpercolative the dielectric relaxation kinetics is proportional to λ-1/λ2, which is consistent with the Gaussian molecular network (affine network) model in the low-strain case.
A tunable colloidal quantum dot photo field-effect transistor
Authors: Ghosh Subir , Hoogland Sjoerd , Sukhovatkin Vlad , Levina Larissa , Sargent Edward H.
Published: September 2011

We fabricate and investigate field-effect transistors in which a light-absorbing photogate modulates the flow of current along the channel. The photogate consists of colloidal quantum dots that efficiently transfer photoelectrons to the channel across a charge-separating (type-II) heterointerface, producing a primary and sustained secondary flow that is terminated via electron back-recombination across the interface. We explore colloidal quantum dot sizes corresponding to bandgaps ranging from 730 to 1475 nm and also investigate various stoichiometries of aluminum-doped ZnO (AZO) channel materials. We investigate the role of trap state energies in both the colloidal quantum dot energy film and the AZO channel.
Niche differentiation of bottlenose dolphin species in South Australia revealed by stable isotopes and stomach contents
Authors: Gibbs Susan E. , Harcourt Robert G. , Kemper Catherine M.
Published: September 2011

Context Animal species with overlapping ranges are common worldwide, but how these species coexist is less obvious. Dolphins are protected in Australia and yet little information is available on their resource use which is essential for successful management and conservation. Aim The aim of this study was to determine the degree of overlap in diet and feeding ecology of the two Tursiops spp. that have overlapping ranges in South Australia. Methods Stomach content (91 Tursiops sp. and 14 T. truncatus) and stable isotope (δ13C, δ15N) analyses (39 Tursiops sp. and 14 T. truncatus) were conducted. Carcasses of dolphins were opportunistically collected between 1974 and 2005. Diet was quantified by frequency of occurrence (FOO) and numerical abundance (NA) of prey. Key results Delta13C from teeth revealed distinct differences in primary source of carbon, corresponding to coastal (Tursiops sp. n = 39,  = –12.24, s.d. = 1.32) and offshore habitats (T. truncatus n = 14,  = –14.21, s.d. = 0.55). Differences in δ15N revealed Tursiops sp. ( = 11.66, s.d. = 0.58) feeds at a lower trophic level than T. truncatus ( = 14.29, s.d. = 0.88). Stomach content analyses for Tursiops sp. corroborated stable isotope results. There was a significant difference between the diets of Tursiops sp. from north Spencer Gulf and south Spencer Gulf (ANOSIM R = 0.249, P = 0.001). Prey were generally demersal in habit with the most important from the cephalopod families Octopodidae, Sepiidae and Loliginidae and fish families Carangidae, Clupeidae, Terapontidae and Apogonidae. For T. truncatus there were insufficient stomach contents for assessment. Conclusions South Australian bottlenose dolphin species exhibit distinct niche differentiation with clear evidence of regional variation in the diet of Tursiops sp. Implications The between and within species diet differentiation demonstrated, highlights the importance of regional management. Such results are internationally significant as coastal and offshore forms of Tursiops spp. occur worldwide.
A qualitative examination of the social practices and representations towards a species of endangered tortoise
Authors: Pérez Irene , Giménez Andrés , Pedreño Andrés
Published: September 2011

Context
Understanding how people view, think and talk about wildlife and the link between wildlife and human behaviour are important for wildlife management to be effective. In this paper, we used the notion of social representations to understand people’s behaviour towards wildlife. We qualitatively studied social representations relating to the keeping in captivity of the endangered tortoise Testudo graeca in south-east Spain.

Aims
The aims were to elucidate social representations towards the spur-thighed tortoise, and to understand the link between social representation and the motivations for collecting and keeping tortoises in captivity. We discuss the conservation implications of social representation towards this tortoise species and provide some management recommendations.

Methods
We carried out 13 in-depth interviews with rural–agrarian, urban and neorural dwellers who kept tortoises in captivity to elucidate social representations towards the spur-thighed tortoise and to understand the link between social representation and the motivations for collecting and keeping tortoises.

Key results
The discourse analysis shows that the social representations of this tortoise as a tameable animal, pet and safeguarded animal co-exist in south-east Spain.

Conclusions
The fact that the social reality in south-east Spain has changed from a social–agrarian society to an urban and neorural society seems to explain these social representations. The conservationist discourse espoused by some respondents partly explains why the habit of keeping tortoises in captivity has prevailed despite social changes in recent decades and this activity being prohibited since the 1970s.

Implications
Our findings reveal the utility of the social representation notion in understanding the social dimensions of wildlife conservation and its applicability to wildlife management.
The use of poison baits to control feral cats and red foxes in arid South Australia I. Aerial baiting trials
Authors: Moseby K. E. , Hill B. M.
Published: September 2011

Context Feral cats and foxes pose a significant threat to native wildlife in the Australian arid zone and their broadscale control is required for the protection of threatened species. Aims The aim of this research was to trial aerial poison baiting as a means of controlling feral cats and foxes in northern South Australia. Methods Eradicat baits or dried meat baits containing 1080 poison were distributed by air over areas of 650 to 1800 km2 in trials from 2002 to 2006. Different baiting density, frequency, bait type and area were trialled to determine the optimum baiting strategy. Baiting success was determined through mortality of radio-collared animals and differences in the track activity of cats and foxes in baited and unbaited areas. Key results Quarterly aerial baiting at a density of 10 baits per square km successfully controlled foxes over a 12-month period, while annual baiting led to reinvasion within four months. Despite the majority of radio-collared cats dying after baiting, a significant decline in cat activity was only recorded during one of the eight baiting events. This event coincided with extremely dry conditions and low rabbit abundance. Rabbit activity increased significantly in baited areas over the study period in comparison with control areas. Conclusions Despite trialling different baiting density, frequency and area over a five-year period, a successful long-term baiting strategy for feral cats could not be developed using Eradicat baits or dried meat baits. Implications Broadscale control of feral cats in the arid zone remains a significant challenge and may require a combination of control methods with flexible delivery times dependent on local conditions. However, it is doubtful that current methods, even used in combination, will enable cat numbers to be reduced to levels where successful reintroductions of many threatened wildlife species can occur.
The use of poison baits to control feral cats and red foxes in arid South Australia II. Bait type, placement, lures and non-target uptake
Authors: Moseby K. E. , Read J. L. , Galbraith B. , Munro N. , Newport J. , Hill B. M.
Published: September 2011

Context
Poison baits are often used to control both foxes and feral cats but success varies considerably.

Aims
This study investigated the influence of bait type, placement and lures on bait uptake by the feral cat, red fox and non-target species to improve baiting success and reduce non-target uptake.

Methods
Six short field trials were implemented during autumn and winter over a five-year period in northern South Australia.

Key results
Results suggest that poison baiting with Eradicat or dried kangaroo meat baits was inefficient for feral cats due to both low rates of bait detection and poor ingestion rates for baits that were encountered. Cats consumed more baits on dunes than swales and uptake was higher under bushes than in open areas. The use of auditory or olfactory lures adjacent to baits did not increase ingestion rates. Foxes consumed more baits encountered than cats and exhibited no preference between Eradicat and kangaroo meat baits. Bait uptake by native non-target species averaged between 14 and 57% of baits during the six trials, accounting for up to 90% of total bait uptake. Corvid species were primarily responsible for non-target uptake. Threatened mammal species investigated and nibbled baits but rarely consumed them; however, corvids and some common rodent species ingested enough poison to potentially receive a lethal dose.

Conclusions
It is likely that several factors contributed to poor bait uptake by cats including the presence of alternative prey, a preference for live prey, an aversion to scavenging or eating unfamiliar foods and a stronger reliance on visual rather than olfactory cues for locating food.

Implications
Further trials for control of feral cats should concentrate on increasing ingestion rates without the requirement for hunger through either involuntary ingestion via grooming or development of a highly palatable bait.
Refuge site selection by the eastern chestnut mouse in recently burnt heath
Authors: Pereoglou F. , Macgregor C. , Banks S. C. , Ford F. , Wood J. , Lindenmayer D. B.
Published: September 2011

Context Temporal reduction in shelter is an indirect primary impact of fire. Removal of animal refugia has implications for shelter site selection and fidelity – factors that have been largely overlooked in studies of Australian rodent fauna. This information is critical for guiding species conservation and appropriate land management including prescribed burning practices. Aims We sought to determine which features of burnt heath were selected as shelter sites by the eastern chestnut mouse, whether there was sex and/or seasonal variation in shelter site selection and whether we could identify primary refugia. Methods We completed a radio-telemetry study to identify diurnal refuge sites and compare habitat attributes with those of a matched set of control sites. We then used habitat features and fidelity parameters to classify refuge site use. Key results We found the eastern chestnut mouse selected shelters with the presence of specific structures and had taller, denser vegetation than randomly selected control sites. There were no differences in habitat selection between the sexes. Shelter sites in the non-breeding season had greater vegetation density compared with those used in the breeding season. In the breeding season, the eastern chestnut mouse showed no evidence of increased fidelity to particular refuges. Vegetation density in winter was the best predictor of a primary refuge compared with whether or not an animal returned to a shelter site or the amount of time spent in a shelter site. Mice were ephemeral and non-gregarious in their refuge use. There was some evidence for inheritance of refuge sites from a parent, as well as inter-season shelter site fidelity. Conclusions The eastern chestnut mouse selected refugia that had habitat attributes offering maximum protection. Seasonality in refuge site selection is likely to reflect the reproductive and environmental trade-offs in critical resources during different seasons. The maintenance of multiple, rarely occupied shelters by the eastern chestnut mouse is consistent with data for other mammals. Implications Fire management should ensure retention of vegetation structure on the ground layer, dense habitat patches in burned areas, and be carefully planned during the winter season to maintain shelter and refuge sites to assist population persistence.
Homeostatic plasticity drives tinnitus perception in an animal model
Authors: Yang Sungchil , Weiner Benjamin D. , Zhang Li S. , Cho Sung-Jin , Bao Shaowen
Published: September 2011

Hearing loss often results in tinnitus and auditory cortical map changes, leading to the prevailing view that the phantom perception is associated with cortical reorganization. However, we show here that tinnitus is mediated by a cortical area lacking map reorganization. High-frequency hearing loss results in two distinct cortical regions: a sensory-deprived region characterized by a decrease in inhibitory synaptic transmission and a normal hearing region showing increases in inhibitory and excitatory transmission and map reorganization. Hearing-lesioned animals displayed tinnitus with a pitch in the hearing loss range. Furthermore, drugs that enhance inhibition, but not those that reduce excitation, reversibly eliminated the tinnitus behavior. These results suggest that sensory deprivation-induced homeostatic down-regulation of inhibitory synapses may contribute to tinnitus perception. Enhancing sensory input through map reorganization may plausibly alleviate phantom sensation.
Investigating a coaxial linear microwave discharge
Authors: Hübner S , Wolthuis J , Palomares J M , van der Mullen J J A M
Published: September 2011

Microwave discharges with powers around 120 W at f = 2.45 GHz created in low pressure argon gas at 0.1–3 mbar were investigated. The microwave energy is fed into a coaxial structure with the plasma as the outer conductor in such a way that a spatially extended surface wave was created. This linear geometry is advantageous for large area plasma processes. The discharge itself was examined spatially resolved by several kinds of optical emission spectroscopic methods. The absolute line intensity of argon 4p levels was measured and the electron temperature could be determined from this with the help of a collisional radiative model. Additionally, the absolute continuum radiation intensity method was employed to determine the electron density.
Influence of irradiation-induced disorder on the Peierls transition in TTF–TCNQ microdomains
Authors: Solovyeva Vita , Cmyrev Anastasia , Sachser Roland , Reith Heiko , Huth Michael
Published: September 2011

The combined influence of electron irradiation-induced defects, substrate-induced strain and finite size effects on the electronic transport properties of individual micron-sized thin film growth domains of the organic charge transfer compound tetrathiafulvalene– tetracyanoquinodimethane (TTF–TCNQ) have been studied. The TTF–TCNQ domains have been isolated and electrically contacted by focused ion beam etching and focused ion and electron-beam-induced deposition, respectively. This allowed us to measure the temperature-dependent resistivity and the current–voltage characteristics of individual domains. The dependence of the resistivity on temperature follows a variable-range hopping behaviour which shows a crossover of the exponents as the Peierls transition is approached. The low temperature behaviour is analysed within the segmented rod model of Fogler, Teber and Shklovskii which was developed for charge-ordered quasi one-dimensional electron crystals (Fogler et al 2004 Phys. Rev. B 69 035413). The effect of substrate-induced biaxial strain on the Peierls transition temperature is discussed with regard to its interplay with the defect-induced changes.
Theoretical and experimental characterization of TiO2 thin films deposited at oblique angles
Authors: Álvarez R , González-García L , Romero-Gómez P , Rico V , Cotrino J , González-Elipe A R , Palmero A
Published: September 2011

The microstructural features of amorphous TiO2 thin films grown by the electron beam physical vapour deposition technique at oblique angles have been experimentally and theoretically studied. The microstructural features of the deposited films were characterized by considering both the column tilt angle and the increase in the column thickness with height. A Monte Carlo model of film growth has been developed that takes into account surface shadowing, short-range interaction between the deposition species and the film surface, as well as the angular broadening of the deposition flux when arriving at the substrate. The good match between simulations and experimental results indicates the importance of these factors in the growth and microstructural development of thin films deposited at oblique angles.
Excess of boron in TiB2 superhard thin films: a combined experimental and ab initio study
Authors: Kalfagiannis N , Volonakis G , Tsetseris L , Logothetidis S
Published: September 2011

Deviations from the nominal stoichiometry are known to affect those properties of TiB2, such as high hardness and metallic character that favour its employment in various technological applications. Here we use a combination of experimental and theoretical approaches to elucidate the dependence of B concentration on controlled growth conditions and the atomic-scale details of excess B incorporation. We find a monotonic increase in B/Ti ratio with the increase in substrate voltage during magnetron sputtering growth of nanocrystalline TiB2 films. Even for large B/Ti ratios, however, the films retain the AlB2 hexagonal structure, albeit with increased lattice constants. Using first-principles calculations we attribute these structural features to incorporation of a portion of excess B as bulk interstitials, while the remaining overstoichiometric B atoms agglomerate on B-rich surfaces of the TiB2 nanograins. The results suggest a link between observed superhardness and B presence on grain surfaces.
Martensitic and magnetic transformation behaviours in Mn50Ni42−xSn8Cox polycrystalline alloys
Authors: Wu Zhigang , Liu Zhuhong , Yang Hong , Liu Yinong , Wu Guangheng
Published: September 2011

This study investigated the effect of Co substitution for Ni in Mn50Ni42Sn8 alloy with the aim of increasing the magnetic driving force for inducing its martensitic transformation. The martensitic transformation temperatures, enthalpy and entropy changes were found to decrease progressively with increasing Co content, while the transformation hysteresis increased. Co substitution for Ni also significantly increased the magnetization of the austenite, but with negligible effect on that of the martensite. A large magnetization difference 109 emu g−1 was achieved across the transformation in a Mn50Ni34Sn8Co8 alloy. The large magnetization difference between the two phases provides enhanced thermodynamic driving force for the transformation. Consequently, the martensitic transformation was induced by the application of a magnetic field in Mn50Ni36Sn8Co6 and Mn50Ni34Sn8Co8 alloys. The effect of Co substitution for Ni on the magnetic interaction among the constituents for the austenite and martensite was clarified in this study, which provides a guide for alloy design for magnetoactuation applications.
Multiple mechanisms driving detachment folding as deduced from 3D reconstruction and geomechanical restoration: the Pico del Águila anticline (External Sierras, Southern Pyrenees)
Authors: Vidal‐Royo Oskar , Cardozo Nestor , Muñoz Josep Anton , Hardy Stuart , Maerten Laurent
Published: September 2011

Three‐dimensional (3D) modelling allows observation of geological features that may not be evident by classical two‐dimensional approaches. This is particularly important in the Pico del Águila anticline (Central External Sierras, Southern Pyrenees, Spain), a structure characterized by important geometrical variability in 3D. The Pico del Águila is a N–S‐trending fold, transverse to the E–W‐trending South‐Pyrenean thrust front, with well‐exposed growth strata that record the evolution of the structure and the influence of the South‐Pyrenean thrust front. Fold kinematics is complex and not precisely quantified. It is characterized by multiple folding mechanisms acting simultaneously in a heterogeneous stratigraphic sequence. To better understand the fold's structural evolution, 3D reconstruction and geomechanical restoration of the structure were performed. The restoration takes into account rock mechanical properties without assuming a specific kinematic model. Our work suggests that the growth of the structure was characterized by variable uplift/sedimentation rates through time and between fold limbs. The restoration also reveals that a combination of multiple folding mechanisms operated simultaneously in different units and structural domains during anti‐clinal growth. This has major implications in the understanding of detachment folds with associated growth strata, as such structures are described in many settings as potential traps for hydrocarbons and natural resources.
Restoring a sense of wellness following colorectal cancer: a grounded theory
Authors: Beech Nicola , Arber Anne , Faithfull Sara
Published: September 2011

beech n., arber a. & faithfull s. (2011) Restoring a sense of wellness following colorectal cancer: a grounded theory. Journal of Advanced Nursing 68(5), 1134–1144.

Aim.  This paper reports a study to develop a grounded theory to explain the experience of recovery following surgery for colorectal cancer.

Background.  Studies have adopted a biomedical framework to measure quality of life and symptom distress following surgery for colorectal cancer. These studies suggest that symptoms of pain, insomnia and fatigue, may persist for many months following treatment. Fewer studies have considered the individual’s experiences and perspective of the emotional, social and cultural aspects of recovery.

Methods.  A longitudinal study using grounded theory was conducted with 12 individuals, who had received surgery for colorectal cancer. Semi‐structured interviews were conducted at four time points over 1 year following surgery, between 2007 and 2009. Grounded theory analysis was undertaken using Strauss and Corbin’s framework.

Findings.  Recovery is described in three phases: disrupting the self; repairing the self; restoring the self. The core category is Restoring a sense of wellness; fostered through awareness and enjoyment of the physical, emotional, spiritual and social aspects of life. A sense of wellness exists as a duality with a sense of illness, where both perspectives may co‐exist but one usually takes precedence. A sense of illness pervades when the individual is preoccupied with illness and the illness continues to disrupt their daily life.

Conclusion.  Recovery takes time and energy, particularly when the individual is at home and in relative isolation from health professionals. Opportunities exist for nurses to provide information and support to facilitate the individual in their progress towards achieving a sense of wellness.
Using Campinha‐Bacote’s process of cultural competence model to examine the relationship between health literacy and cultural competence
Authors: Ingram Racquel Richardson
Published: September 2011

ingram r.r. (2012) Using Campinha‐Bacote’s process of cultural competence model to examine the relationship between health literacy and cultural competence. Journal of Advanced Nursing68(3), 695–704.

Aim.  This paper presents a discussion of the relation between health literacy and cultural competence in nursing practice.

Background.  Cultural competence involves understanding values, beliefs, traditions and customs of diverse groups. Health literacy is the degree to which individuals can obtain, process, and understand health information to make healthcare decisions. Cultural competence and health literacy are directly related to healthcare. Campinha‐Bacote’s Process of Cultural Competence Model can assist nurses in addressing cultural issues associated with a person’s low health literacy.

Data sources.  Literature searches were performed using CINAHL, ERIC, Academic Search Premier, Health Source Nursing, MasterFILE Premier and Academic OneFile. All articles reviewed were published in peer reviewed journals in English from the 1990s to the present and were relevant to health literacy and cultural competence in nursing. Books and other supporting scholarly sources were also used.

Discussion.  Health literacy and cultural competence are related. Applying Campinha‐Bacote’s Process of Cultural Competence Model using the mnemonic ASKED (awareness, skills, knowledge, encounters and desire) involves incorporating culturally appropriate assessments and disseminating healthcare information at lower literacy levels and is needed for nurses to provide care for ethnic minorities and diverse populations.

Implications for nursing.  Health literacy should be assessed and care should be based on a client’s level of understanding and cultural values and norms.

Conclusion.  Nurses can care for ethnic minorities by using resources that target health literacy deficits and by increasing their own cultural competence.
Termite activity, not grazing, is the main determinant of spatial variation in savanna herbaceous vegetation
Authors: Okullo Paul , Moe Stein R.
Published: September 2011

1. Termites and large herbivores represent important functional groups in savanna ecosystems. Termites affect vegetation far beyond their mounds. In addition, large herbivores feed selectively on termite mound vegetation or in the vicinity of mounds. Previous studies of savanna vegetation communities have focused on termites and large herbivores separately, although interaction effects may be predicted.

2. We studied the effects of large herbivores and large vegetated Macrotermes mounds on the herbaceous vegetation in Lake Mburo National Park in Uganda. We recorded herbaceous vegetation change over 3 years on savanna areas (with and without large herbivores) and on corresponding termite mounds (with and without large herbivores) in a randomized block design.

3. Termite mounds and savannas had significantly different plant communities, but large herbivore grazing exclusions did not result in significant shifts in plant communities during this study period. A canonical correspondence analysis separated species mainly along an axis from termitaria to savanna. Only a few species responded to grazing exclusion. Some erect species, such as Hyparrhenia filipendula and Themeda triandra, increased in cover, and creeping species, such as Cynodon dactylon, decreased, following the exclusion of grazers. Forbs dominated mound areas, while graminoids dominated the savanna areas. Fencing increased the cover of graminoids over time and led to gradual increase in the relative cover of graminoids compared with forbs.

4. Mound soil was higher in pH, calcium and magnesium and lower in sodium compared with adjacent savanna areas. Nitrogen and carbon soil content did not differ between the two habitats. Soil phosphorus increased following grazing exclusion.

5. Synthesis. This study shows that termites may exert a far more important effect on the herbaceous community than large herbivores in savanna areas, even if the biomass of large herbivores is relatively high. Thus, future studies on savanna vegetation ecology should focus increasingly on important insect groups in addition to the more conspicuous large mammal guild.
The Lys20 homocitrate synthase isoform exerts most of the flux control over the lysine synthesis pathway in Saccharomyces cerevisiae
Authors: Quezada Héctor , Marín‐Hernández Alvaro , Aguilar Diana , López Geovani , Gallardo‐Pérez Juan Carlos , Jasso‐Chávez Ricardo , González Alicia , Saavedra Emma , Moreno‐Sánchez Rafael
Published: September 2011

In Saccharomyces cerevisiae, the first committed step in the lysine (Lys) biosynthetic pathway is catalysed by the Lys20 and Lys21 homocitrate synthase (HCS) isoforms. Overexpression of Lys20 resulted in eightfold increased Lys, as well as 2‐oxoglutarate pools, which were not attained by overexpressing Lys21 or other pathway enzymes (Lys1, Lys9 or Lys12). A metabolic control analysis‐based strategy, by gradually and individually manipulating the Lys20 and Lys21 activities demonstrated that the cooperative and strongly feedback‐inhibited Lys21 isoform exerted low control of the pathway flux whereas most of the control resided on the non‐cooperative and weakly feedback‐inhibited Lys20 isoform. Therefore, the higher control of Lys20 over the Lys flux represents an exception to the dogma of higher pathway control by the strongest feedback‐inhibited enzyme and points out to multi‐site engineering (HCS isoforms and supply of precursors) to increase Lys synthesis.
Day/night regulation of aquaporins during the CAM cycle in Mesembryanthemum crystallinum
Authors: VERA‐ESTRELLA ROSARIO , BARKLA BRONWYN J. , AMEZCUA‐ROMERO JULIO C. , PANTOJA OMAR
Published: September 2011

Mesembryanthemum crystallinum exhibits induction of Crassulacean acid metabolism (CAM) after a threshold stage of development, by exposure to long days with high light intensities or by water and salt stress. During the CAM cycle, fluctuations in carbon partitioning within the cell lead to transient drops in osmotic potential, which are likely stabilized/balanced by passive movement of water via aquaporins (AQPs). Protoplast swelling assays were used to detect changes in water permeability during the day/night cycle of CAM. To assess the role of AQPs during the same period, we followed transcript accumulation and protein abundance of four plasma membrane intrinsic proteins (PIPs) and one tonoplast intrinsic protein (TIP). CAM plants showed a persistent rhythm of specific AQP protein abundance changes throughout the day/night cycle, including changes in amount of McPIP2;1, McTIP1;2, McPIP1;4 and McPIP1;5, while the abundance of McPIP1;2 was unchanged. These protein changes did not appear to be coordinated with transcript levels for any of the AQPs analysed; however, they did occur in parrallel to alterations in water permeability, as well as variations in cell osmolarity, pinitol, glucose, fructose and phosphoenolpyruvate carboxylase (PEPc) levels measured throughout the day/night CAM cycle. Results suggest a role for AQPs in maintaining water balance during CAM and highlight the complexity of protein expression during the CAM cycle.
Genome‐wide transcriptome dissection of the rice root system: implications for developmental and physiological functions
Authors: Takehisa Hinako , Sato Yutaka , Igarashi Motoko , Abiko Tomomi , Antonio Baltazar A. , Kamatsuki Kaori , Minami Hiroshi , Namiki Nobukazu , Inukai Yoshiaki , Nakazono Mikio , Nagamura Yoshiaki
Published: September 2011

The root system is a crucial determinant of plant growth potential because of its important functions, e.g. uptake of water and nutrients, structural support and interaction with symbiotic organisms. Elucidating the molecular mechanism of root development and functions is therefore necessary for improving plant productivity, particularly for crop plants, including rice (Oryza sativa). As an initial step towards developing a comprehensive understanding of the root system, we performed a large‐scale transcriptome analysis of the rice root via a combined laser microdissection and microarray approach. The crown root was divided into eight developmental stages along the longitudinal axis and three radial tissue types at two different developmental stages, namely: epidermis, exodermis and sclerenchyma; cortex; and endodermis, pericycle and stele. We analyzed a total of 38 microarray data and identified 22 297 genes corresponding to 17 010 loci that showed sufficient signal intensity as well as developmental‐ and tissue type‐specific transcriptome signatures. Moreover, we clarified gene networks associated with root cap function and lateral root formation, and further revealed antagonistic and synergistic interactions of phytohormones such as auxin, cytokinin, brassinosteroids and ethylene, based on the expression pattern of genes related to phytohormone biosynthesis and signaling. Expression profiling of transporter genes defined not only major sites for uptake and transport of water and nutrients, but also distinct signatures of the radial transport system from the rhizosphere to the xylem vessel for each nutrient. All data can be accessed from our gene expression profile database, RiceXPro (http://ricexpro.dna.affrc.go.jp), thereby providing useful information for understanding the molecular mechanisms involved in root system development of crop plants.
Media coverage of cervical cancer and the HPV vaccine: implications for geographic health inequities
Authors: Krieger Janice L. , Katz Mira L. , Eisenberg Dana , Heaner Sarah , Sarge Melanie , Jain Parul
Published: September 2011

Objective  To describe the content of newspaper articles about cervical cancer and the human papillomavirus (HPV) vaccine published in Appalachia and identify potential differences in coverage as compared to the content of newspaper articles published in non‐Appalachia Ohio.

Background  Individuals rely on media as an important source of health information. Inadequate coverage of health issues may reinforce health inequities such as the elevated cervical cancer incidence and mortality rates in Appalachia Ohio.

Methods  A content analysis was conducted of all newspaper articles about cervical cancer and the HPV vaccine published in Appalachia and non‐Appalachia Ohio during 2006.

Findings  A total of 121 published newspaper articles (42 in Appalachia and 79 in non‐Appalachia) about cervical cancer and the HPV vaccine were identified. Articles published in Appalachia Ohio were significantly less likely than articles published in non‐Appalachia Ohio to provide information about the threat of cervical cancer and the efficacy of the HPV vaccine. Specifically, few articles published in Appalachia included information about the ability of the vaccine to prevent cervical cancer, the cost of the vaccine and the availability of assistance programmes for the un‐ and underinsured.

Conclusions  Newspaper articles printed in the Appalachia region lacked vital information that could help promote uptake of the HPV vaccine. Health educators and healthcare providers should be aware that women from underserved geographic regions like Appalachia may have greater information needs regarding their risk of cervical cancer and the potential benefits of the HPV vaccine as compared to the general patient population.
Is atopic dermatitis predictable?
Authors: Beyer Kirsten , Wahn Ulrich
Published: September 2011

Atopic dermatitis (AD) is a common skin disease which affects 10 to 20% of the population, usually with onset during infancy. The frequency of AD appears to have increased over the past three decades. Attempts to identify parameters predictive of the development of AD have been made by many investigators during the last decades. Although genetic factors remain unmodifiable, avoidance of relevant trigger factors could modify the development of AD. This paper reviews and discusses findings of the last several years and outlines recent advances in genetic studies of AD. In spite of decades of intensive research and newly developed technology, the parental history of AD appears to be the most valuable predictive parameter. However, the predictive capacity is not sufficient to recommend it as screening instrument. At this time, a perinatal screening with the objective of primary prevention of AD does not seem feasible.
Concentrations of retinol, 3,4‐didehydroretinol, and retinyl esters in plasma of free‐ranging birds of prey
Authors: Müller K. , Raila J. , Altenkamp R. , Schmidt D. , Dietrich R. , Hurtienne A. , Wink M. , Krone O. , Brunnberg L. , Schweigert F. J.
Published: September 2011

This study investigated vitamin A compounds in the plasma of healthy free‐ranging Central European raptors with different feeding strategies. Plasma samples of nestlings of white‐tailed sea eagle [white‐tailed sea eagle (WTSE), Haliaeetus albicilla) (n = 32), osprey (Pandion haliaetus) (n = 39), northern goshawk (Accipiter gentilis) (n = 25), common buzzard (Buteo buteo) (n = 31), and honey buzzard (Pernis apivorus) (n = 18) and adults of WTSE (n = 10), osprey (n = 31), and northern goshawk (n = 45) were investigated with reversed‐phase‐high‐performance liquid chromatography (RP‐HPLC). In WTSE, northern goshawks and common buzzards retinol were the main plasma component of vitamin A, whilst in ospreys and honey buzzards, 3,4‐didehydroretinol predominated. The median of the retinol plasma concentration in the nestlings group ranged from 0.12 to 3.80 μm and in the adult group from 0.15 to 6.13 μm. Median plasma concentrations of 3,4‐didehydroretinol in nestlings ranged from 0.06 to 3.55 μm. In adults, northern goshawks had the lowest plasma concentration of 3,4‐didehydroretinol followed by WTSE and ospreys. The plasma of all investigated species contained retinyl esters (palmitate, oleate, and stearate). The results show considerable species‐specific differences in the vitamin A plasma concentrations that might be caused by different nutrition strategies.
Energy intake for maintenance in a mammal with a low basal metabolism, the giant anteater (Myrmecophaga tridactyla)
Authors: Stahl M. , Osmann C. , Ortmann S. , Kreuzer M. , Hatt J.‐M. , Clauss M.
Published: September 2011

Giant anteaters (Myrmecophaga tridactyla) are among those mammals for which a particularly low metabolism has been reported. In order to verify presumably low requirements for energy, we used eight anteaters (two males, six females; aged 1–14 years; body mass between 46 and 64 kg) in a total of 64 individual trials, in which a variety of intake levels was achieved on various diets. Digestible energy (DE) intake was quantified by measuring food intake and faecal excretion and analysing representative samples for gross energy, and animals were weighed regularly. Maintenance DE requirements were calculated by regression analysis for the DE intake that corresponded to zero weight change. Differences between individuals were significant. Older anteaters (n = 3 animals aged 12–15 years in 29 trials) had lower relative requirements than younger ones (n = 5 animals aged 1–7 years in 35 trials); thus, giant anteaters resemble other mammals in which similar age‐specific differences in energy requirements are known. However, estimated maintenance requirements were 347 kJ DE/kg0.75/day in the anteaters, which is low compared to the 460–580 kJ DE/kg0.75/day maintenance requirements of domestic dogs. The lack of knowledge that metabolic requirements are below the mammalian average could make species particularly susceptible to overfeeding, if amounts considered adequate for average mammals were provided. Non‐scientific reports on comparatively fast growth rates and high body masses in captive giant anteaters as compared to free‐ranging animals suggest that body mass development and feeding regimes in captivity should be further assessed.
GAPDH: A common enzyme with uncommon functions
Authors: Nicholls Craig , Li He , Liu Jun‐Ping
Published: September 2011

1. Glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) has long been recognized as an important enzyme for energy metabolism and the production of ATP and pyruvate through anaerobic glycolysis in the cytoplasm.

2. Recent studies have shown that GAPDH has multiple functions independent of its role in energy metabolism. Although increased GAPDH gene expression and enzymatic function is associated with cell proliferation and tumourigenesis, conditions such as oxidative stress impair GAPDH catalytic activity and lead to cellular aging and apoptosis.

3. The mechanism(s) underlying the effects of GAPDH on cellular proliferation remains unclear, yet much evidence has been accrued that demonstrates a variety of interacting partners for GAPDH, including proteins, various RNA species and telomeric DNA.

4. The present mini review summarizes recent findings relating to the extraglycolytic functions of GAPDH and highlights the significant role this enzyme plays in regulating both cell survival and apoptotic death.
Examination of the anterior uveoscleral pathway in domestic species
Authors: Sedacca Kara , Samuelson Don , Lewis Patricia
Published: September 2011

Objective  To investigate the uveoscleral (US) pathway in the normal eyes of four domestic spp.: the cat, pig, cow and horse by examining the comparative anatomical structure of anterior US pathway.

Animals studied  Four cats, ten pigs, four cows, eight horses.

Procedures  Formalin‐preserved specimens from anterior uveas of the cat, pig, cow and horse were embedded and serially sectioned sagittally and tangentially and stained with H&E, Masson’s trichrome, smooth muscle actin immunolabel, or elastin stain.

Results  Spaces between the endings of the outer anterior ciliary body musculature (CBM) formed avenues for the beginning of the US pathway and varied in the amount of extracellular matrix (ECM) material being most developed in the pig. In the cow, other anterior muscle bundles attached the CBM to the sclera concomitant with the presence of an anterior elastic sheath. In the horse, these muscle bundles were connected to branching connective tissue trabeculae within the US pathway that were attached radially to the sclera. In the cat, muscle bundles were more abundant and formed a fine meshwork of trabecular associations with the posterior ICA. Supraciliary development was most pronounced in the horse and least in the pig.

Conclusion  All species possessed clearly developed and unique US pathways. The outermost muscle bundles of the CBM appeared to have close interaction with the US pathway and the degree of these muscle associations differed with species. The species specific anatomical variations within the US pathway could play a pivotal role in the variability of aqueous outflow along this pathway.
Does Ethnic Discrimination Vary Across Minority Groups? Evidence from a Field Experiment*
Authors: Booth Alison L. , Leigh Andrew , Varganova Elena
Published: September 2011

We conduct a large‐scale field experiment to measure labour market discrimination in Australia, one quarter of whose population was born overseas. To denote ethnicity, we use distinctively Anglo‐Saxon, Indigenous, Italian, Chinese and Middle Eastern names. We compare multiple ethnic groups, rather than a single minority as in most other studies. In all cases we applied for entry‐level jobs and submitted a CV indicating that the candidate attended high school in Australia. We find significant differences in callback rates: ethnic minority candidates would need to apply for more jobs in order to receive the same number of interviews. These differences vary systematically across ethnic groups.
MRI‐based intravenous thrombolysis in stroke patients with unknown time of symptom onset
Authors: Ebinger M. , Scheitz J. F. , Kufner A. , Endres M. , Fiebach J. B. , Nolte C. H.
Published: September 2011

Background:  Currently, stroke patients with unknown time of symptom onset (UTOS) are excluded from therapy with intravenous tissue Plasminogen Activator. We hypothesized that MRI‐based intravenous thrombolysis is safe in UTOS.

Methods:  We analyzed radiological and clinical data as well as outcomes of stroke patients (including UTOS) who received intravenous thrombolytic therapy after MRI.

Results:  Compared to patients with known time of symptom onset (n = 131), UTOS (n = 17) were older (81, 71–88 vs. 75 years, 66–82, P = 0.03), had a longer median time between last‐seen‐well and thrombolysis (12.3 h, IQR 11.5–15.2 h vs. 2.1 h, 1.8–2.8 h, P < 0.01), had a longer median door‐to‐needle time (86 min, 49–112 vs. 60 min, 49–76, P = 0.02), and a higher rate of arterial obstruction on MR‐angiography (82.4% vs. 56.5%, P = 0.04). No symptomatic intracerebral hemorrhage occurred in UTOS. After 3 months, there was no significant difference between groups concerning good functional outcome (modified Rankin Scale 0–2; 35.3% vs. 49.6%, P = 0.26) or mortality (0% vs. 15.3%, P = 0.08). In multivariate analyses including age, gender, baseline NIHSS, and atrial fibrillation UTOS did not have an independent effect on good functional outcome after 3 months (OR 1.16; 0.32–4.12, P = 0.81).

Conclusions:  Thrombolysis after MRI seems safe and effective in UTOS. This observation may encourage those who plan prospective placebo‐controlled trials of thrombolytics in this subgroup of stroke patients.