bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling opto-electronic properties of a dye molecule in proximity of a semiconductor nanoparticle
Authors: Delgado Alain , Corni Stefano , Goldoni Guido
Published: July 2013

A general methodology is presented to model the opto-electronic properties of a dye molecule in the presence of a semiconductor nanoparticle (NP), a model system for the architecture of dye-sensitized solar cells. The method is applied to the L0 organic dye solvated with acetonitrile in the neighborhood of a TiO2 NP. The total reaction potential due to the polarization of the solvent and the metal oxide is calculated by extending the polarizable continuum model integral equation formalism. The ground state energy is computed by using density functional theory (DFT) while the vertical electronic excitations are obtained by time-dependent DFT in a state-specific corrected linear response scheme. We calculate the excited state oxidation potential (ESOP) for the protonated and deprotonated forms of the L0 dye at different distances and configurations with respect to the NP surface. The stronger renormalizations of the ESOP values due to the presence of the TiO2 nanostructure are found for the protonated dye, reaching a maximum of about −0.15 eV. The role of protonation effect is discussed in terms of the atomic Löwdin charges of the oxidized and reduced species. On the other hand, we observed a weak effect on the L0 optical excitation gap due to the polarization response of the NP.
Controlling the efficiency of trapping in treelike fractals
Authors: Wu Bin , Zhang Zhongzhi
Published: July 2013

Efficiently controlling the trapping process, especially the trapping efficiency, is central in the study of trap problem in complex systems, since it is a fundamental mechanism for diverse other dynamic processes. Thus, it is of theoretical and practical significance to study the control technique for trapping problem. In this paper, we study the trapping problem in a family of proposed directed fractals with a deep trap at a central node. The directed fractals are a generalization of previous undirected fractals by introducing the directed edge weights dominated by a parameter. We characterize all the eigenvalues and their degeneracies for an associated matrix governing the trapping process. The eigenvalues are provided through an exact recursive relation deduced from the self-similar structure of the fractals. We also obtain the expressions for the smallest eigenvalue and the mean first-passage time (MFPT) as a measure of trapping efficiency, which is the expected time for the walker to first visit the trap. The MFPT is evaluated according to the proved fact that it is approximately equal to reciprocal of the smallest eigenvalue. We show that the MFPT is controlled by the weight parameter by modifying which the MFPT can scale superlinealy, linearly, or sublinearly with the system size. Thus, this work paves a way to delicately controlling the trapping process in the fractals.
Development of a fast radiation detector based on barium fluoride scintillation crystal
Authors: Han Hetong , Zhang Zichuan , Weng Xiufeng , Liu Junhong , Guan Xingyin , Zhang Kan , Li Gang
Published: July 2013

Barium fluoride (BaF2) is an inorganic scintillation material used for the detection of X/gamma radiation due to its relatively high density, equivalent atomic number, radiation hardness, and high luminescence. BaF2 has a potential capacity to be used in gamma ray timing experiments due to the prompt decay emission components. It is known that the light output from BaF2 has three decay components: two prompt of those at approximately 195 nm and 220 nm with a decay constant around 600-800 ps and a more intense, slow component at approximately 310 nm with a decay constant around 630 ns which hinders fast timing experiments. We report here the development of a fast radiation detector based on a BaF2 scintillation crystal employing a special optical filter device, a multiple reflection multi-path ultraviolet region short-wavelength pass light guides (MRMP-short pass filter) by using selective reflection technique, for which the intensity of the slow component is reduced to less than 1%. The methods used for this study provide a novel way to design radiation detector by utilizing scintillation crystal with several emission bands.
Full-F gyrofluid model
Authors: Madsen Jens
Published: July 2013

A global electromagnetic gyrofluid model based on the full-F gyrokinetic model is derived. The gyrofluid moment variables are not split into fluctuating and equilibrium parts. Profiles are evolved freely, and gyro-averaging operators are not parametrized, but are functions of the gyrofluid moment variables. The fluid moment hierarchy is closed by approximating the gyrokinetic distribution function as a finite order Hermite-Laguerre polynomial and by determining closure approximations for terms involving the gyrokinetic gyro-averaging operator. The model exactly conserves the gyrokinetic full-F energy invariant evaluated using the Hermite-Laguerre decomposition. The model is suited for qualitative studies of the interplay between turbulence, flows, and dynamically evolving profiles in magnetically confined plasmas.
Electron perpendicular viscosity in Braginskii's equations
Authors: Wong S. K. , Chan V. S.
Published: July 2013

The viscosity coefficient of the electron perpendicular stress tensor in Braginskii's theory is corrected by the addition of a term of the same order of magnitude, through the inclusion of a term beyond pitch angle scattering in the mass-ratio expansion of the electron-ion collision operator.
Strain-induced defects as nonradiative recombination centers in green-emitting GaInN/GaN quantum well structures
Authors: Langer Torsten , Jönen Holger , Kruse Andreas , Bremers Heiko , Rossow Uwe , Hangleiter Andreas
Published: July 2013

The origin of the green gap for GaInN/GaN quantum wells is investigated via temperature-dependent time-resolved photoluminescence spectroscopy. A strong correlation between nonradiative lifetimes and total strain energy is observed, although the wells are almost fully strained. We discuss this observation in terms of nonradiative recombination at defects which contribute to a beginning partial relaxation. The formation energy of a defect is likely reduced by the amount of its released strain energy. We therefore expect an exponential dependence of the defect density on this released strain energy. Our measured nonradiative lifetimes are consistent with a cumulative strain driven generation of defects.
Low threshold, room-temperature microdisk lasers in the blue spectral range
Authors: Aharonovich Igor , Woolf Alexander , Russell Kasey J. , Zhu Tongtong , Niu Nan , Kappers Menno J. , Oliver Rachel A. , Hu Evelyn L.
Published: July 2013

InGaN-based active layers within microcavity resonators offer the potential of low threshold lasers in the blue spectral range. Here, we demonstrate optically pumped, room temperature lasing in high quality factor GaN microdisk cavities, containing InGaN quantum dots (QDs) with thresholds as low as 0.28 mJ/cm2. The demonstration of lasing action from GaN microdisk cavities with QDs in the active layer, provides a critical step for the nitrides in realizing low threshold photonic devices with efficient coupling between QDs and an optical cavity
Negative refraction in graphene-based hyperbolic metamaterials
Authors: Sreekanth K. V. , De Luca A. , Strangi G.
Published: July 2013

Here, we numerically investigate the existence of negative group refraction in graphene-based hyperbolic metamaterials (HMM) at THz frequencies. The hyperbolic dispersion of the graphene-based HMM can be tuned by varying the chemical potential and surrounding dielectric layer thickness. The negative group and positive phase indices of refraction are observed for oblique incidence at far below the critical frequency, which permits negative energy refraction and forward wavefront propagation. The highly confined bulk plasmon modes are also observed in the negative group index region that further evidence the negative refraction behaviour of the graphene-based hyperbolic metamaterials.
High performance plasmonic random laser based on nanogaps in bimetallic porous nanowires
Authors: Shi Xiaoyu , Wang Yanrong , Wang Zhaona , Sun Yanyan , Liu Dahe , Zhang Yongyi , Li Qingwen , Shi Jinwei
Published: July 2013

A plasmonic random laser is fabricated using gold-silver bimetallic porous nanowires with abundant nanogaps that provide strong feedback or gain channels for coherent lasing from dye molecules. The strong confinement of the nanogaps allows the bimetallic porous nanowire-based random laser, which is pumped by ns pulses, to operate with a very low threshold and extremely low concentrations of Rhodamine 6 G (as low as 0.067 mM). This random laser can be used as a pump source for another coherent random laser based on oxazine. These results provide a basis for studies of coherent random lasing pumped by another random laser.
Thermomechanical strain measurements by synchrotron x-ray diffraction and data interpretation for through-silicon vias
Authors: Liu X. , Thadesar P. A. , Taylor C. L. , Kunz M. , Tamura N. , Bakir M. S. , Sitaraman S. K.
Published: July 2013

To study thermomechanical strain induced by the mismatch of coefficients of thermal expansion in through-silicon vias (TSVs) and thus provide fundamental understanding of TSV reliability, strain measurements have been performed with synchrotron x-ray diffraction (XRD). The measured strains are available as two-dimensional (2D) distribution maps, whereas the strain distributions in TSVs are three-dimensional (3D) in nature. To understand this 3D to 2D data projection process, a data interpretation method based on beam intensity averaging is proposed and validated with measurements. The proposed method is applicable to XRD strain measurements on thin as well as thick samples.
Planning for whole-farm systems research at a credible scale: subdividing land into farmlets with equivalent initial conditions
Authors: Scott J. M. , Munro M. , Rollings N. , Browne W. , Vickery P. J. , Macgregor C. , Donald G. E. , Sutherland H.
Published: July 2013

Most research comparing different farming systems has been conducted on relatively uniform plots at small scales made necessary by the desire for sufficient replication of the systems and cost limitations. This paper describes an alternative approach to plan the allocation of land to three unreplicated whole-farm management systems such that each farmlet had equivalent starting conditions and yet was at a scale credible to both livestock producers and researchers. The paddocks of each farmlet were distributed across the landscape in a ‘patchwork quilt’ pattern after six iterations of a mapping exercise using a Geographic Information System. Allocation of paddocks took into account those variables of the landscape and natural resource capacity that were not able to be altered. An important benefit of the procedure was that it ensured that the farmlets were co-located with contiguous paddock boundaries so that all farmlets experienced the same climatic as well as biophysical conditions. An electromagnetic survey was conducted of the entire property and used in conjunction with a detailed soils map in order to classify areas into soil conductivity groupings. Equivalent areas of each soil type were allocated across the three farmlets. Similarly, land was distributed according to its topography so that no farmlet would be compromised by being allocated more low lying, flood-prone land than any other farmlet. The third factor used to allocate land to each farmlet was the prior fertiliser history of the original paddocks. This process ensured that each farmlet was objectively allocated equivalent areas of soil type, topography and fertiliser history thus avoiding initial bias among the farmlets. After the plan for all paddocks of each farmlet was finalised, new paddock boundaries were drawn and where necessary, fencing was removed, modified and added, along with re-arranged watering points. The farmlet treatments commenced in July 2000 when the first pasture establishment and differential fertiliser applications were carried out. Evidence from the electromagnetic survey and the Landsat imagery confirmed that the distribution of hydrologic soil conductivity and vegetation greenness were similar between all farmlets just before the commencement of the experiment.
Five-year survival and growth of farm forestry plantings of native trees and radiata pine in pasture affected by position in the landscape
Authors: Reid Nick , Reid Jackie , Hoad Justin , Green Stuart , Chamberlain Greg , Scott J. M.
Published: July 2013

Woodlots ranging in area from 0.18 to 0.5 ha were established within the Cicerone Project farmlet trial on the Northern Tablelands of New South Wales, Australia, due to a lack of physical protection in most paddocks across the farmlets. Two percent of each farmlet was planted to trees to examine the commercial and environmental potential of seven species to provide shade and shelter for livestock, increase biodiversity or contribute to cash flow through farm forestry diversification. Eucalyptus caliginosa (timber), E. nitens (timber, pulp wood), E. radiata (essential oil) and Pinus radiata (timber) were planted in four upslope plots (1059–1062 m a.s.l.) in different paddocks. Casuarina cunninghamiana (timber, shelter), E. acaciiformis (shade, shelter and biodiversity), E. dalrympleana (timber, biodiversity), E. nitens (timber, pulp wood), E. radiata (essential oil) and P. radiata (timber) were planted in four low-lying plots (1046–1050 m a.s.l.) in separate paddocks, 400–1200 m distant. The pines and natives were planted in August and October 2003, respectively, into a well prepared, weed-free, mounded, planting bed. After 5 years, P. radiata (98% survival) and E. nitens (83%) survived best in upslope plots, reaching maximum heights of 7.8 and 8.8 m and exhibiting no or only modest insect damage, respectively. In low-lying plots, E. acaciiformis (75% survival) and E. dalrympleana (80%) survived best, reaching maximum heights of 5.5 and 4.5 m, and exhibiting little or only moderate insect damage, respectively. P. radiata exhibited 17–69% survival in the two lowest-lying plots but 100% survival in the other two lowland plots. On average, <50% of C. cunninghamiana, E. nitens and E. radiata survived in low-lying plots and survivors grew poorly. Early frosts in March 2004 were the primary cause of losses in low-lying plots, and frost, waterlogging, insect attack and some inadvertent livestock browsing explain the slower growth of species in low-lying plots compared with their performance upslope. P. radiata and perhaps E. nitens have commercial promise for timber production on Northern Tablelands farms, but only in higher (well drained, less frost-prone) parts of the landscape. E. acaciiformis can withstand the stressful growing conditions in open pasture in low-lying plots, and should be planted more widely for on-farm shade and shelter. E. dalrympleana can also be considered for amenity and biodiversity plantings in lower parts of the landscape.
Thermodynamic framework for identifying free energy inventories of enzyme catalytic cycles
Authors: Fried Stephen D. , Boxer Steven G.
Published: July 2013

Pauling’s suggestion that enzymes are complementary in structure to the activated complexes of the reactions they catalyze has provided the conceptual basis to explain how enzymes obtain their fantastic catalytic prowess, and has served as a guiding principle in drug design for over 50 y. However, this model by itself fails to predict the magnitude of enzymes’ rate accelerations. We construct a thermodynamic framework that begins with the classic concept of differential binding but invokes additional terms that are needed to account for subtle effects in the catalytic cycle’s proton inventory. Although the model presented can be applied generally, this analysis focuses on ketosteroid isomerase (KSI) as an example, where recent experiments along with a large body of kinetic and thermodynamic data have provided strong support for the noncanonical thermodynamic contribution described. The resulting analysis precisely predicts the free energy barrier of KSI’s reaction as determined from transition-state theory using only empirical thermodynamic data. This agreement is suggestive that a complete free energy inventory of the KSI catalytic cycle has been identified.
Person‐Centred and Experiential Psychotherapy Scale: Development and reliability of an adherence/competence measure for person‐centred and experiential psychotherapies
Authors: Freire Elizabeth , Elliott Robert , Westwell Graham
Published: July 2013

Aims: This study aimed to assess the reliability of the Person‐Centred and Experiential Psychotherapy Scale (PCEPS), a new adherence/competence measure of person‐centred and experiential psychotherapies. The PCEPS consists of 15 items with two subscales: Person-Centred Process and Experiential Process. Method: One‐hundred twenty audio‐recorded segments of therapy sessions were rated independently by two teams of three raters using the PCEPS. Half of the segments were 10 minutes long and the other half were 15 minutes long. Six therapists were experienced therapists and four were counsellors in training. Seven of the therapists identified their work as ‘person‐centred’, and three identified their work as ‘process‐experiential’. Three raters were qualified and experienced person‐centred therapists and three raters were person‐centred counselling trainees in their first year of training. Results: Interrater reliabilities were good (alpha: .68–.86), especially when ratings were averaged across items (alpha: .87); interitem reliabilities were quite high (alpha: .98). Exploratory factor analyses revealed a 12‐item facilitative relationship factor that cuts across Person‐Centred and Experiential subscales (alpha: .98), and a nonfacilitative directiveness factor (3 items, alpha: .89). Conclusions/Implications: The PCEPS has potential for use in RCT research as well as in counselling training and supervision, but will require further testing and validation.
Effects of a carbohydrate and caffeine gel on intermittent sprint performance in recreationally trained males
Authors: Cooper Robert , Naclerio Fernando , Allgrove Judith , Larumbe‐Zabala Eneko
Published: July 2013

We investigated the effects of ingesting carbohydrate gels with and without caffeine on a ~90‐minute, four blocks intermittent sprint test (IST), in 12 recreationally trained male athletes. Using a cross‐over design, one 70 ml dose of gel containing either 25 g of carbohydrate with (CHOCAF) or without (CHO) 100 mg of caffeine, or a non‐caloric placebo (PL) was ingested on three occasions: one hour before, immediately prior to and during the IST. Blood glucose, rating of perceived exertion (RPE) and fatigue index (FI) were analysed. Glucose showed significantly higher values for both CHOCAF and CHO at the first (p=0.005 and p=0.000, respectively), second (p=0.009 and 0.008, respectively) and third (p=0.003 and 0.001, respectively) blocks when compared with PL, while only CHOCAF was significantly different to PL (p=0.002) at the fourth block. CHOCAF showed an improved FI (mean 5.0, s =1.7) compared with CHO (mean 7.6, s =2.6; p=0.006) and PL (mean 7.4, s =2.4; p=0.005), a significantly lower RPE (mean 14.2, s =2) compared with PL (mean 15.3, s =2; p=0.003) and a trend in respect of CHO (mean 14.9, s =2.3; p=0.056) after the third block. In conclusion, ingesting CHOCAF one hour before, prior to and during an IST is effective at transiently reducing fatigue and RPE whilst maintaining higher glucose levels at the final stages of the exercise.
Intra‐individual movement variability during skill transitions: A useful marker?
Authors: Carson Howie J. , Collins Dave , Richards Jim
Published: July 2013

Applied research suggests that athletes and coaches need to be challenged in knowing when and how much a movement should be consciously attended to. This is exacerbated when the skill is in transition between two more stable states, such as when an already well‐learnt skill is being refined. Using existing theory and research, this paper highlights the potential application of movement variability as a tool to inform a coach's decision‐making process when implementing a systematic approach to technical refinement. Of particular interest is the structure of co‐variability between mechanical degrees‐of‐freedom (e.g., joints) within the movement system's entirety when undergoing a skill transition. Exemplar data from golf are presented, demonstrating the link between movement variability and mental effort as an important feature of automaticity, and thus intervention design throughout the different stages of refinement. Movement variability was shown to reduce when mental effort directed towards an individual aspect of the skill was high (target variable). The opposite pattern was apparent for variables unrelated to the technical refinement. Therefore, two related indicators, movement variability and mental effort, are offered as a basis through which the evaluation of automaticity during technical refinements may be made.
Fractional iteration of series and transseries
Authors: Edgar G.
Published: July 2013

We investigate compositional iteration of fractional order for transseries. For any large positive transseries

T
T

of exponentiality

0
0

, there is a family

T

[
s
]

T^{[s]}

indexed by real numbers

s
s

corresponding to iteration of order

s
s

. It is based on Abel’s Equation. We also investigate the question of whether there is a family

T

[
s
]

T^{[s]}

all sharing a single support set. A subset of the transseries of exponentiality

0
0

is divided into three classes (“shallow”, “moderate” and “deep”) with different properties related to fractional iteration.
Suppression of Pythium and Phytophthora Damping-Off of Rooibos by Compost and a Combination of Compost and Nonpathogenic Pythium Taxa
Authors: Bahramisharif Amirhossein , Lamprecht Sandra C. , Calitz Frikkie , McLeod Adéle
Published: July 2013

Pathogenic oomycetes, including Phytophthora cinnamomi and several Pythium spp. (Pythium irregulare, P. mamillatum, P. myriotylum, and P. pyrilobum), cause serious damping-off problems in rooibos (Aspalathus linearis) nurseries. The management of these pathogens in organic nurseries is problematic, because phenylamide fungicides may not be used. Compost, or compost in combination with Pythium taxa that are nonpathogenic to rooibos (P. acanthicum, P. cederbergense, and Pythium RB II), were investigated as alternative management options. Compost was able to suppress damping-off caused by several oomycete isolates but there was within- and between-species variation among the 30 evaluated isolates. This phenomenon was observed using two compost batches (A and B) sourced from independent suppliers. Compost B significantly reduced damping-off caused by 60% of the isolates, whereas compost A controlled only 37% of the isolates. The pathogens that were more readily controlled by both composts included P. mamillatum and P. pyrilobum, whereas the composts were ineffective at suppressing damping-off caused by >62% of P. irregulare and >50% of P. myriotylum isolates. Based on the evaluation of one Phytophthora cinnamomi isolate, this pathogen may also be controlled by compost. Neither of the composts as a stand-alone treatment could suppress damping-off caused by a combination of pathogenic species (P. cinnamomi, Pythium irregulare, P. mamillatum, P. myriotylum, and P. pyrilobum). However, damping-off was significantly reduced when nonpathogenic Pythium taxa (P. acanthicum, P. cederbergense, and Pythium RB II) were combined with the composts. Similarly, damping-off caused by a P. irregulare isolate that was not suppressed by either of the composts alone was significantly suppressed when the two composts were inoculated with the nonpathogenic Pythium taxa.
Integrated Control of Potato Pathogens Through Seed Potato Certification and Provision of Clean Seed Potatoes
Authors: Frost Kenneth E. , Groves Russell L. , Charkowski Amy O.
Published: July 2013

Long-term data sets are rare in agriculture, and the impact of plant diseases on food production is challenging to measure, which makes it difficult to assess the impact of policy changes or research-based disease control efforts. Despite this challenge, it is clear that one of the largest impacts of biological research on food security over the past century has been in production of vegetatively propagated fruit and vegetable crops such as potato. The yield and quality of these crops is higher in countries that have effective plant propagation and certification systems. Of these systems, seed potato production and certification is among the most developed. We analyzed a dataset from a century-old seed potato certification program in Wisconsin to assess the efficacy for potato disease control and the cost of this program compared to other disease control and potato production costs. We found that over the past century, certification has gradually reduced the incidence of mechanically transmitted vascular potato pathogens that lack insect vectors to undetectable levels, and much of this reduction occurred prior to the use of tissue culture and the development of immunoassays. Rejection of seed lots from certification is now rare, with Potato virus Y (PVY), a virus spread nonpersistently by numerous, noncolonizing aphid species, and farmer errors being the main causes of rejection. PVY level increases occurred in 2000, coincident with the first detection of a new invasive vector, soybean aphid, in the Midwest. The increased PVY incidence was more pronounced in varieties that exhibit mild foliar symptoms. Starting in 2004, a decrease in PVY incidence occurred following comprehensive science-based changes to early generation seed potato production. The cost of the certification program has not increased in two decades, and the fees charged are comparable to those in 1913. The cooperative nature of the seed potato certification program has contributed to its sustainability across generations. However, looming soilborne disease problems are not easily addressed by certification and will likely cause significant challenges in the future.
Sir Alan Marshall Muir Wood FREng FICE. 8 August 1921 — 1 February 2009
Authors: Burland John B. , Mair Robert J.
Published: July 2013

Sir Alan Muir Wood was a civil engineer who gained worldwide recognition for his pioneering and innovative tunnelling design and construction. In the early years of his career he was much concerned with coastal erosion and landslides. Later he became involved in some of the world’s major tunnelling projects, among them the Potters Bar railway tunnels, the Clyde Tunnel, the Channel Tunnel and the 50-mile water-carrying Orange–Fish Tunnel in South Africa. Each project saw him pushing forwards innovation in different aspects of design. The cargo tunnel at Heathrow Airport has been described as his most influential design and a testament to his analytical skills, his creativity in design and his vast experience in the handling of the inevitable uncertainties and risks associated with tunnelling. As might be expected for such an innovative engineer he took a keen interest in research and in engineering education. He relished robust technical debate and intellectual challenge and, even after ‘retirement’, was regularly involved in construction litigation and arbitration, for which he developed a formidable reputation for his clarity of thought and penetrating evidence. Although extremely modest, he was a natural leader in his profession and was widely respected for his absolute integrity (being elected President of the Institution of Civil Engineers).
Spatial heterogeneity enhances and modulates excitability in a mathematical model of the myometrium
Authors: Sheldon Rachel E. , Baghdadi Marc , McCloskey Conor , Blanks Andrew M. , Shmygol Anatoly , van den Berg Hugo A.
Published: July 2013

The muscular layer of the uterus (myometrium) undergoes profound changes in global excitability prior to parturition. Here, a mathematical model of the myocyte network is developed to investigate the hypothesis that spatial heterogeneity is essential to the transition from local to global excitation which the myometrium undergoes just prior to birth. Each myometrial smooth muscle cell is represented by an element with FitzHugh–Nagumo dynamics. The cells are coupled through resistors that represent gap junctions. Spatial heterogeneity is introduced by means of stochastic variation in coupling strengths, with parameters derived from physiological data. Numerical simulations indicate that even modest increases in the heterogeneity of the system can amplify the ability of locally applied stimuli to elicit global excitation. Moreover, in networks driven by a pacemaker cell, global oscillations of excitation are impeded in fully connected and strongly coupled networks. The ability of a locally stimulated cell or pacemaker cell to excite the network is shown to be strongly dependent on the local spatial correlation structure of the couplings. In summary, spatial heterogeneity is a key factor in enhancing and modulating global excitability.
Trailing edge noise theory for rotating blades in uniform flow
Authors: Sinayoko S. , Kingan M. , Agarwal A.
Published: July 2013

This paper presents a new formulation for trailing edge noise radiation from rotating blades based on an analytical solution of the convective wave equation. It accounts for distributed loading and the effect of mean flow and spanwise wavenumber. A commonly used theory due to Schlinker and Amiet predicts trailing edge noise radiation from rotating blades. However, different versions of the theory exist; it is not known which version is the correct one, and what the range of validity of the theory is. This paper addresses both questions by deriving Schlinker and Amiet's theory in a simple way and by comparing it with the new formulation, using model blade elements representative of a wind turbine, a cooling fan and an aircraft propeller. The correct form of Schlinker and Amiet's theory is identified. It is valid at high enough frequency, i.e. for a Helmholtz number relative to chord greater than one and a rotational frequency much smaller than the angular frequency of the noise sources.
Thermal inclusions inside a bounded medium
Authors: Zou W.-N. , He Q.-C. , Zheng Q.-S.
Published: July 2013

In the context of thermal conduction taken as a prototype of numerous transport phenomena, a general method is elaborated to study Eshelby's problem of inclusions inside a bounded homogeneous anisotropic medium. This method consists in: (i) recasting by a linear transformation the initial problem into Eshelby's problem of the transformed inclusion inside the transformed finite isotropic medium and (ii) decomposing Eshelby's problem of a thermal inclusion embedded in a finite isotropic medium into the sub-problem of the same inclusion inside the associated infinite medium and the sub-problem of the finite ambient isotropic medium including no inclusion but undergoing appropriate compensating boundary conditions. The general method is applied in the two-dimensional situation and the corresponding temperature field and Eshelby's conduction tensor are explicitly expressed in terms of some curvilinear complex integrals for the Dirichlet and Neumann boundary conditions. Thus, the difficulties owing to the unavailability or non-existence of Green's function are overcome. The general results in the two-dimensional case are finally specified and illustrated by considering a finite circular medium with circular or polygonal inclusions.
Pre-Columbian origins of Native American dog breeds, with only limited replacement by European dogs, confirmed by mtDNA analysis
Authors: van Asch Barbara , Zhang Ai-bing , Oskarsson Mattias C. R. , Klütsch Cornelya F. C. , Amorim António , Savolainen Peter
Published: July 2013

Dogs were present in pre-Columbian America, presumably brought by early human migrants from Asia. Studies of free-ranging village/street dogs have indicated almost total replacement of these original dogs by European dogs, but the extent to which Arctic, North and South American breeds are descendants of the original population remains to be assessed. Using a comprehensive phylogeographic analysis, we traced the origin of the mitochondrial DNA lineages for Inuit, Eskimo and Greenland dogs, Alaskan Malamute, Chihuahua, xoloitzcuintli and perro sín pelo del Peru, by comparing to extensive samples of East Asian (n= 984) and European dogs (n= 639), and previously published pre-Columbian sequences. Evidence for a pre-Columbian origin was found for all these breeds, except Alaskan Malamute for which results were ambigous. No European influence was indicated for the Arctic breeds Inuit, Eskimo and Greenland dog, and North/South American breeds had at most 30% European female lineages, suggesting marginal replacement by European dogs. Genetic continuity through time was shown by the sharing of a unique haplotype between the Mexican breed Chihuahua and ancient Mexican samples. We also analysed free-ranging dogs, confirming limited pre-Columbian ancestry overall, but also identifying pockets of remaining populations with high proportion of indigenous ancestry, and we provide the first DNA-based evidence that the Carolina dog, a free-ranging population in the USA, may have an ancient Asian origin.
Reproductive system of a mixed-mating plant responds to climate perturbation by increased selfing
Authors: Jones N. T. , Husband B. C. , MacDougall A. S.
Published: July 2013

How plants respond to climatic perturbations, which are forecasted to increase in frequency and intensity, is difficult to predict because of the buffering effects of plasticity. Compensatory adjustments may maintain fecundity and recruitment, or delay negative changes that are inevitable but not immediately evident. We imposed a climate perturbation of warming and drought on a mixed-mating perennial violet, testing for adjustments in growth, reproduction and mortality. We observed several plasticity-based buffering responses, such that the climatic perturbation did not alter population structure. The most substantial reproductive adjustments, however, involved selfing, with a 45% increase in self-pollination by chasmogamous flowers, a 61% increase in the number of cleistogamous flowers that produced at least one fruit and an overall 15% increase in fruit production from selfed cleistogamous flowers. Reproductive assurance thus compensated for environmental change, including low pollinator visitation that occurred independently of our climate treatment. There was also no immediate evidence for inbreeding depression. Our work indicates that plants with vegetative and reproductive flexibility may not be immediately and negatively affected by a climatic perturbation. The stabilizing effects of these reproductive responses in the long term, however, may depend on the implications of significantly elevated levels of selfing.
The evolution of predictive adaptive responses in human life history
Authors: Nettle Daniel , Frankenhuis Willem E. , Rickard Ian J.
Published: July 2013

Many studies in humans have shown that adverse experience in early life is associated with accelerated reproductive timing, and there is comparative evidence for similar effects in other animals. There are two different classes of adaptive explanation for associations between early-life adversity and accelerated reproduction, both based on the idea of predictive adaptive responses (PARs). According to external PAR hypotheses, early-life adversity provides a ‘weather forecast’ of the environmental conditions into which the individual will mature, and it is adaptive for the individual to develop an appropriate phenotype for this anticipated environment. In internal PAR hypotheses, early-life adversity has a lasting negative impact on the individual's somatic state, such that her health is likely to fail more rapidly as she gets older, and there is an advantage to adjusting her reproductive schedule accordingly. We use a model of fluctuating environments to derive evolveability conditions for acceleration of reproductive timing in response to early-life adversity in a long-lived organism. For acceleration to evolve via the external PAR process, early-life cues must have a high degree of validity and the level of annual autocorrelation in the individual's environment must be almost perfect. For acceleration to evolve via the internal PAR process requires that early-life experience must determine a significant fraction of the variance in survival prospects in adulthood. The two processes are not mutually exclusive, and mechanisms for calibrating reproductive timing on the basis of early experience could evolve through a combination of the predictive value of early-life adversity for the later environment and its negative impact on somatic state.
Inferring the causes of the three waves of the 1918 influenza pandemic in England and Wales
Authors: He Daihai , Dushoff Jonathan , Day Troy , Ma Junling , Earn David J. D.
Published: July 2013

Past influenza pandemics appear to be characterized by multiple waves of incidence, but the mechanisms that account for this phenomenon remain unclear. We propose a simple epidemic model, which incorporates three factors that might contribute to the generation of multiple waves: (i) schools opening and closing, (ii) temperature changes during the outbreak, and (iii) changes in human behaviour in response to the outbreak. We fit this model to the reported influenza mortality during the 1918 pandemic in 334 UK administrative units and estimate the epidemiological parameters. We then use information criteria to evaluate how well these three factors explain the observed patterns of mortality. Our results indicate that all three factors are important but that behavioural responses had the largest effect. The parameter values that produce the best fit are biologically reasonable and yield epidemiological dynamics that match the observed data well.
Behavioural fever is a synergic signal amplifying the innate immune response
Authors: Boltaña Sebastian , Rey Sonia , Roher Nerea , Vargas Reynaldo , Huerta Mario , Huntingford Felicity Anne , Goetz Frederick William , Moore Janice , Garcia-Valtanen Pablo , Estepa Amparo , MacKenzie S.
Published: July 2013

Behavioural fever, defined as an acute change in thermal preference driven by pathogen recognition, has been reported in a variety of invertebrates and ectothermic vertebrates. It has been suggested, but so far not confirmed, that such changes in thermal regime favour the immune response and thus promote survival. Here, we show that zebrafish display behavioural fever that acts to promote extensive and highly specific temperature-dependent changes in the brain transcriptome. The observed coupling of the immune response to fever acts at the gene–environment level to promote a robust, highly specific time-dependent anti-viral response that, under viral infection, increases survival. Fish that are not offered a choice of temperatures and that therefore cannot express behavioural fever show decreased survival under viral challenge. This phenomenon provides an underlying explanation for the varied functional responses observed during systemic fever. Given the effects of behavioural fever on survival and the fact that it exists across considerable phylogenetic space, such immunity–environment interactions are likely to be under strong positive selection.
Sympodiomycopsis yantaiensis sp. nov., a basidiomycetous yeast isolated from insect frass
Authors: Chen Liang , Zhang Lin , Li Zhi-Hui , Hui Feng-Li
Published: July 2013

Two strains (NYNU 121010Tand NYNU 121032) of a novel basidiomycetous yeast species belonging to the genusSympodiomycopsiswere isolated from insect frass collected from trunks of a pagoda tree (Sophora japonicaL.) in Yantai, Shandong province, east China. The sequence analyses of the D1/D2 domain of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region indicated that the closest relatives wereSympodiomycopsis kandeliaeFIRDI 007T,Sympodiomycopsis paphiopediliCBS 7429TandSympodiomycopsissp. S6A. The D1/D2 sequences of the novel strains differed by 12 nt substitutions (2 %) from the type strain ofS.kandeliae, and by 13 nt substitutions (2.2 %) from the type strain ofS.paphiopediliand fromSympodiomycopsissp. S6A. The novel strains differed from closely related species by more than 4.6 % substitutions in the ITS region. The novel strains can also be distinguished fromS.kandeliaeandS.paphiopedilion the basis of a number of morphological and physiological characteristics and represent a novel species in the genusSympodiomycopsis, for which the nameSympodiomycopsis yantaiensissp. nov. is proposed. The type strain is NYNU 121010T( = CICC 32998T = CBS 12813T). The Mycobank deposit number is MB 804119.
Numerical resolution of Emden's equation using Adomian polynomials
Authors: José Pujol María , Pujol Francisco A. , Aznar Fidel , Pujol Mar , Rizo Ramón
Published: July 2013

Purpose

In this paper the authors aim to show the advantages of using the decomposition method introduced by Adomian to solve Emden's equation, a classical non‐linear equation that appears in the study of the thermal behaviour of a spherical cloud and of the gravitational potential of a polytropic fluid at hydrostatic equilibrium.

Design/methodology/approach

In their work, the authors first review Emden's equation and its possible solutions using the Frobenius and power series methods; then, Adomian polynomials are introduced. Afterwards, Emden's equation is solved using Adomian's decomposition method and, finally, they conclude with a comparison of the solution given by Adomian's method with the solution obtained by the other methods, for certain cases where the exact solution is known.

Findings

Solving Emden's equation for n in the interval [0, 5] is very interesting for several scientific applications, such as astronomy. However, the exact solution is known only for n=0, n=1 and n=5. The experiments show that Adomian's method achieves an approximate solution which overlaps with the exact solution when n=0, and that coincides with the Taylor expansion of the exact solutions for n=1 and n=5. As a result, the authors obtained quite satisfactory results from their proposal.

Originality/value

The main classical methods for obtaining approximate solutions of Emden's equation have serious computational drawbacks. The authors make a new, efficient numerical implementation for solving this equation, constructing iteratively the Adomian polynomials, which leads to a solution of Emden's equation that extends the range of variation of parameter n compared to the solutions given by both the Frobenius and the power series methods.
Predictions of round impinging jet heat transfer with two k‐ω hybrid RANS/LES models
Authors: Kubacki Slawomir , Rokicki Jacek , Dick Erik
Published: July 2013

Purpose

Applicability of two k‐ω hybrid RANS/LES and a k‐ω RANS models is studied for simulation of round impinging jets at nozzle‐plate distance H/D=2 with Reynolds number 70000, H/D=2 with Reynolds number 5000 and H/D=10 with Reynolds number 5000 (D is the nozzle exit diameter). The aim is to verify two concepts of unified hybrid RANS/LES formulations, one of DES (Detached Eddy Simulation) type and one of LNS (Limited Number Scales) type in analysis of impinging jet flow and heat transfer. The grid resolution requirements are also discussed.

Design/methodology/approach

The simulations are performed with two k‐ω based hybrid RANS/LES models of very different nature, one of DES type and one of LNS type, and the RANS k‐ω model. For the lower Reynolds number (5000), also dynamic Smagorinsky LES is done. Both hybrid model formulations converge to the same RANS k‐ω model in the near‐wall region and have the same Smagorinsky limit on fine isotropic grids in the LES mode of the hybrid models.

Findings

With the hybrid RANS/LES models, improved fluid flow and heat transfer results are obtained compared to RANS, in the impact region and in the developing wall‐jet region. For accurate predictions at low nozzle‐plate distance, where the impact region is in the core of the jet, it is necessary to sufficiently resolve the formation and breakup of the near‐wall vortices in the jet impingement region and the developing wall‐jet region, as these determine largely the level of fluctuating velocity and the heat transfer. This requires high grid resolution for high Reynolds number, while the grid resolution requirements stay modest for low Reynolds number.

Originality/value

The paper demonstrates that two formulations of hybrid RANS/LES models of different nature, one of DES type and one of LES type, lead to equivalent results. Consistency has been guaranteed in the sense that the RANS limit of both models is the same and that the LES limit on fine, isotropic, grids is the same. In the intermediate range, however, the repartition into resolved and modelled fluctuations may differ considerably.
Enhancing the egg's natural defence against bacterial penetration by increasing cuticle deposition
Authors: Bain M. M. , Mcdade K. , Burchmore R. , Law A. , Wilson P. W. , Schmutz M. , Preisinger R. , Dunn I. C.
Published: July 2013

The cuticle is a proteinaceous layer covering the avian egg and is believed to form a defence to microorganism ingress. In birds that lay eggs in challenging environments, the cuticle is thicker, suggesting evolutionary pressure; however, in poultry, selection pressure for this trait has been removed because of artificial incubation. This study aimed to quantify cuticle deposition and to estimate its genetic parameters and its role on trans‐shell penetration of bacteria. Additionally, cuticle proteins were characterised to establish whether alleles for these genes explained variation in deposition. A novel and reliable quantification was achieved using the difference in reflectance of the egg at 650 nm before and after staining with a specific dye. The heritability of this novel measurement was moderate (0.27), and bacteria penetration was dependent on the natural variation in cuticle deposition. Eggs with the best cuticle were never penetrated by bacteria (P < 0.001). The cuticle proteome consisted of six major proteins. A significant association was found between alleles of one of these protein genes, ovocleidin‐116 (MEPE), and cuticle deposition (P = 0.015) and also between alleles of estrogen receptor 1 (ESR1) gene and cuticle deposition (P = 0.008). With the heritability observed, genetic selection should be possible to increase cuticle deposition in commercial poultry, so reducing trans‐generational transmission of microorganisms and reversing the lack of selection pressure for this trait during recent domestication.
Evaluation of cardiac output in intensive care using a non‐invasive arterial pulse contour technique (Nexfin®) compared with echocardiography
Authors: Taton O. , Fagnoul D. , De Backer D. , Vincent J.‐L.
Published: July 2013

In this prospective study, cardiac output was measured in 38 intensive care unit patients before and after a fluid challenge, using both pulse contour analysis (Nexfin®; BMEYE, Amsterdam, the Netherlands) and transthoracic echocardiography. The ability of the Nexfin device to detect significant changes in the velocity–time integral was evaluated. The pulse wave could not be detected by the Nexfin device in five patients (13%), leaving 33 patients for analysis. The Nexfin device adequately tracked changes in the velocity–time integral in 20 (61%) patients. Using a cut‐off of a 10% increase in cardiac output estimated by the Nexfin or by echocardiography, the sensitivity of the Nexfin device to detect a response to fluid challenge was 47%, with specificity 81% and accuracy 64%. The percentage error between the Nexfin and echocardiography was 448%; lower limit of agreement −48% (95% CI −62 to −36%) and upper limit of agreement, 32% (95% CI 20–45%). We conclude that the Nexfin device does not adequately track changes in cardiac output in critically ill patients.