bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct observational evidence linking atmospheric aerosol formation and cloud droplet activation
Authors: Kerminen Veli‐Matti , Lihavainen Heikki , Komppula Mika , Viisanen Yrjö , Kulmala Markku
Published: July 2005

In order to predict the current state and future development of the Earth's climate system, detailed knowledge on how atmospheric aerosol particles from various sources interact with clouds is needed. In this article we present, based on continuous aerosol measurements in a remote continental location, direct observational evidence that aerosol particles formed in the atmosphere from gaseous precursors eventually participate into cloud droplet activation. By combining the measurement data with theoretical calculations, we further demonstrate that the albedo of clouds may be significantly influenced by atmospheric aerosol formation, and that this process needs to be taken into account when estimating the indirect climatic effects of aerosols in the global atmosphere.
Evidence of explosive seafloor volcanic activity from the Walvis Ridge, South Atlantic Ocean
Authors: Haxel J. H. , Dziak R. P.
Published: July 2005

Hydrophones moored in the North Atlantic Ocean recorded a sequence of explosive, volcano‐acoustic signals originated at the Walvis Ridge in the South Atlantic Ocean. 365 explosive signals were detected from the Walvis Ridge beginning 24 November 2001 continuing through March 2002. The largest swarm began on 19 December at 2329 GMT, and lasted 1.25 hrs producing 32 locatable events. Swarm locations are centered on the northern flank of an unnamed seamount (−32.96°S; −5.22°W), northwest of Wüst Seamount. These signals are interpreted as volcanogenic explosions due to similarities with acoustic signals recorded from a confirmed submarine eruption in the Caribbean in 2001 (Kick'em Jenny volcano). The observations presented suggest recent magmatic activity along the Walvis Ridge may be unrelated to the Tristan da Cunha mantle plume. Furthermore, these events lend support for an extensional fracture‐zone model resulting in the recurrence of volcanic activity along older segments of large‐scale sea floor lineaments.
Enhancement of ENSO's persistence barrier by biennial variability in a coupled atmosphere‐ocean general circulation model
Authors: Yu Jin‐Yi
Published: July 2005

Possible causes of the spring persistence barrier in ENSO sea surface temperature anomalies are examined using a coupled atmosphere‐ocean general circulation model (CGCM). Our study indicates that the persistence barrier is significantly enhanced when both Pacific and Indian Ocean couplings are included in the CGCM, compared to the simulation that includes only the Pacific Ocean coupling. ENSO's variance, phase locking to the annual cycle, and biennial variability are also increased in the Indo‐Pacific Run. Further analysis reveals that the overall amplitude of ENSO is not a primary factor in determining the strength of the persistence barrier, rather, it is the amplitude of the biennial component of ENSO affecting the barrier the most. The persistence barrier is consistently strong (weak) when biennial ENSO variability is large (small). No such a clear relationship is found between the strength of the barrier and the amplitude of the low‐frequency (3–5 years) component of ENSO. This modeling study demonstrates that the biennial component of ENSO is one major mechanism responsible for the spring persistence barrier and that interactions between the tropical Pacific Ocean and Indian Ocean‐monsoon could enhance the biennial component of ENSO.
Animated Interval Scatter-Plot Views for the Exploratory Analysis of Large-Scale Microarray Time-Course Data
Authors: Craig Paul , Kennedy Jessie , Cumming Andrew
Published: July 2005

Microarray technologies are a relatively new development that allow biologists to monitor the activity of thousands of genes (normally around 8,000) in parallel across multiple stages of a biological process. While this new perspective on biological functioning is recognised as having the potential to have a significant impact on the diagnosis, treatment, and prevention of diseases, it is only through effective analysis of the data produced that biologists can begin to unlock this potential. A significant obstacle to achieving effective analysis of microarray time-course is the combined scale and complexity of the data. This inevitably makes it difficult to reveal certain significant patterns in the data. In particular, it is less dominant patterns and, specifically, patterns that occur over smaller intervals of an experiment's overall time-frame that are more difficult to find. While existing techniques are capable of finding either unexpected patterns of activity over the majority of an experiment's time-frame or expected patterns of activity over smaller intervals of the time-frame, there are no techniques, or combination of techniques, that are suitable for finding unsuspected patterns of activity over smaller intervals. In order to overcome this limitation we have developed the Time-series Explorer, which specifically supports biologists in their attempts to reveal these types of pattern by allowing them to control an animated interval scatter-plot view of their data. This paper discusses aspects of the technique that make such an animated overview viable and describes the results of a user evaluation assessing the practical utility of the technique within the wider context of microarray time-series analysis as a whole.
Dynamical behavior of entanglements by means of the mean standard deviation
Authors: Wacha Marcus , Kreitmeier Stefan
Published: July 2005

In this paper we present our results on the dynamical behavior within the interior parts of an entanglement. Therefore, we analyzed the mean standard deviation sm for each monomer of the entangled chains. The calculations were performed at two deformation ratios for three different basic systems—the cross, slant, and along systems—each of them representing a different structural orientation of the entanglement. Additionally, we varied the number of loops l, the distance a of the end monomers, and the inverse temperature β. Depending on the number of loops l we get different effects. Whereas a one time entangled system rather acts like a chemical cross link, a six times entangled system forms an unoriented entangled area and an orientated residual part.
Electron-phonon interactions in photoinduced excited electronic states in fluoroacenes
Authors: Kato Takashi , Yamabe Tokio
Published: July 2005

The electron-phonon coupling constants [lB1u(HOMO→LUMO)] in the photoinduced excited electronic states in fluoroacenes are estimated and compared with those in the monoanions (lLUMO) and cations (lHOMO). The lB1u(HOMO→LUMO) values are much larger than the lLUMO and lHOMO values in fluoroacenes. Furthermore, the Coulomb pseudopotential μ* values for the excited electronic states are estimated to be smaller than those for the monoanions and cations. The complete phase patterns difference between the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) is the main reason why the electron-phonon coupling constants and the μ* values are larger and smaller, respectively, in the photoinduced excited electronic states than in the monoanions and cations. The possible electron pairing and Bose–Einstein condensation in the excited electronic states of fluoroacenes are discussed. Because of larger electron-phonon coupling constants and smaller μ* values in the excited electronic states than in the charged states, the conditions under which the electron-electron interactions become attractive can be more easily realized, in principle, in the excited electronic states than in the charged states in fluoroacenes. The lB1u(HOMO→LUMO) values hardly change by H–F substitution, even though the lLUMO and lHOMO values significantly increase by H–F substitution in acenes. Antibonding interactions between carbon and fluorine atoms in the HOMO and LUMO are the main reason why the lB1u(HOMO→LUMO) values hardly change by H–F substitution in acenes.
Monte Carlo operators for ions interacting with radio frequency waves
Authors: Eriksson L.-G. , Schneider M.
Published: July 2005

Monte Carlo operators for the interaction between rf waves and ions in a tokamak are derived. The operators are intended for orbit following codes that use an acceleration scheme, i.e., where one calculated orbit represents many real orbits. The derivation starts from an orbit averaged quasi-linear diffusion operator, and local Monte Carlo operators are obtained by formulating this operator for a special set of phase space variables. The resulting Monte Carlo operators include the effects of wave-induced transport in both velocity and real space. Furthermore, the operators are applicable to arbitrary axisymmetric geometry.
Novel crystalline carbon-cage structure synthesized from laser-driven shock wave loading of graphite
Authors: Luo Sheng-Nian , Tschauner Oliver , Tierney Thomas E. , Swift Damian C. , Chipera Steve J. , Asimow Paul D.
Published: July 2005

We report a novel crystalline carbon-cage structure synthesized from laser-driven shock wave loading of a graphite-copper mixture to about 14±2GPa and 1000±200K. Quite unexpectedly, it can be structurally related to an extremely compressed three-dimensional C60 polymer with random displacement of C atoms around average positions equivalent to those of distorted C60 cages. Thus, the present carbon-cage structure represents a structural crossing point between graphite interlayer bridging and C60 polymerization as the two ways of forming diamond from two-dimensional and molecular carbon.
Hard-sphere radial distribution function again
Authors: Trokhymchuk Andrij , Nezbeda Ivo , Jirsák Jan , Henderson Douglas
Published: July 2005

A theoretically based closed-form analytical equation for the radial distribution function, g(r), of a fluid of hard spheres is presented and used to obtain an accurate analytic representation. The method makes use of an analytic expression for the short- and long-range behaviors of g(r), both obtained from the Percus-Yevick equation, in combination with the thermodynamic consistency constraint. Physical arguments then leave only three parameters in the equation of g(r) that are to be solved numerically, whereas all remaining ones are taken from the analytical solution of the Percus-Yevick equation.
Multiphase regimes of single-surface multipactor
Authors: Semenov V. , Nechaev V. , Rakova E. , Zharova N. , Anderson D. , Lisak M. , Puech J.
Published: July 2005

Single-surface multipactor is studied within a plane-parallel model for the case when the rf electric field is normal to the surface of emission and the electron return to this surface is caused by the action of a dc electric field. The corresponding resonance zones are found for finite initial velocity of the secondary electrons. The new multiphase regimes of multipactor are found by numerical simulations of a successive series of electron trajectories. The existence of these regimes is shown to result in a considerable broadening of the multipactor zones. This conclusion is also confirmed by particle-in-cell simulations.
Current singularities at finitely compressible three-dimensional magnetic null points
Authors: Pontin D. I. , Craig I. J. D.
Published: July 2005

The formation of current singularities at line-tied two- and three-dimensional (2D and 3D, respectively) magnetic null points in a nonresistive magnetohydrodynamic environment is explored. It is shown that, despite the different separatrix structures of 2D and 3D null points, current singularities may be initiated in a formally equivalent manner. This is true no matter whether the collapse is triggered by flux imbalance within closed, line-tied null points or driven by externally imposed velocity fields in open, incompressible geometries. A Lagrangian numerical code is used to investigate the finite amplitude perturbations that lead to singular current sheets in collapsing 2D and 3D null points. The form of the singular current distribution is analyzed as a function of the spatial anisotropy of the null point, and the effects of finite gas pressure are quantified. It is pointed out that the pressure force, while never stopping the formation of the singularity, significantly alters the morphology of the current distribution as well as dramatically weakening its strength. The impact of these findings on 2D and 3D magnetic reconnection models is discussed.
Titanium-doped indium oxide: A high-mobility transparent conductor
Authors: van Hest M. F. A. M. , Dabney M. S. , Perkins J. D. , Ginley D. S. , Taylor M. P.
Published: July 2005

We report on the effects of titanium doping (0–7at.%) on the optical and electrical properties of In2O3 using combinatorial deposition and analysis techniques. Maximum mobilities are observed at Ti concentrations of 1.5–2.5at.% and are >80cm2∕Vs in sputtered films. The carrier concentration increased with titanium content to a high of 8.0×1020cm−3. Data show that one carrier is generated per added Ti between 1 and 3at.%. Conductivities up to 6260Ω−1cm−1 were observed. These remained very high >5000Ω−1cm−1 across a wide compositional range. The optical transparency is high (>85%) in a wide spectral range from 400nm to at least 1750nm. The work function of titanium-doped indium oxide varies substantially over the studied compositional range.
Influence of the anneal conditions on arsenic activation during solid-phase epitaxial regrowth
Authors: Pawlak B. J. , Duffy R. , Janssens T. , Vandervorst W. , Maex K. , Smith A. J. , Cowern N. E. B. , Dao T. , Tamminga Y.
Published: July 2005

We investigate the influence of the initial stage of the thermal treatment during solid-phase epitaxial regrowth (SPER) on the electrical activation level of arsenic in self-amorphized silicon, both with respect to heating ramp-up rates and the use of low-temperature preanneals. Enhancement of the electrically-active arsenic concentration by 14% is observed for activation with the fastest ramp-up rates (430°C∕s) compared to the slowest ones (36°C∕s). Around 50% of the 1015at∕cm2, arsenic implant at 5 keV is found to be nonsubstitutional and this fraction reaches even 99% for dose 3×1015at∕cm2. Arsenic clustering in silicon amorphous phase during SPER is recognized to play an important role in the decrease of the active dose.
Atomistic study of GaN surface grown on Si(111)
Authors: Wang Z. T. , Yamada-Takamura Y. , Fujikawa Y. , Sakurai T. , Xue Q. K.
Published: July 2005

GaN is directly grown on Si(111) by radio-frequency plasma-assisted molecular-beam epitaxy, and the surface is studied using in situ reflection high-energy electron diffraction (RHEED) and scanning tunneling microscopy (STM). By optimizing the growth condition, well-defined surface reconstructions are observed in atomically-resolved STM images after the additional Ga deposition, indicating the uniform N-polarity of the grown film. We show that N-rich condition in the initial GaN growth and slightly Ga-rich condition in the subsequent growth are critical in order to achieve monopolar uniform GaN films.
Complementary sex determination substantially increases extinction proneness of haplodiploid populations
Authors: Zayed Amro , Packer Laurence
Published: July 2005

The role of genetic factors in extinction is firmly established for diploid organisms, but haplodiploids have been considered immune to genetic load impacts because deleterious alleles are readily purged in haploid males. However, we show that single-locus complementary sex determination ancestral to the haplodiploid Hymenoptera (ants, bees, and wasps) imposes a substantial genetic load through homozygosity at the sex locus that results in the production of inviable or sterile diploid males. Using stochastic modeling, we have discovered that diploid male production (DMP) can initiate a rapid and previously uncharacterized extinction vortex. The extinction rate in haplodiploid populations with DMP is an order of magnitude greater than in its absence under realistic but conservative demographic parameter values. Furthermore, DMP alone can elevate the base extinction risk in haplodiploids by over an order of magnitude higher than that caused by inbreeding depression in threatened diploids. Thus, contrary to previous expectations, haplodiploids are more, rather than less, prone to extinction for genetic reasons. Our findings necessitate a fundamental shift in approaches to the conservation and population biology of these ecologically and economically crucial insects.
Biochemical evidence for the requirement of Hoogsteen base pairing for replication by human DNA polymerase ι
Authors: Johnson Robert E. , Prakash Louise , Prakash Satya
Published: July 2005

Because of the near geometric identity of Watson-Crick (W-C) G·C and A·T base pairs, a given DNA polymerase forms the four possible correct base pairs with nearly identical catalytic efficiencies. However, human DNA polymerase ι (Polι), a member of the Y family of DNA polymerases, exhibits a marked template specificity, being more efficient at incorporating the correct nucleotide opposite template purines than opposite pyrimidines. By using 7-deazaadenine and 7-deazaguanine as the templating residues, which disrupt Hoogsteen base pair formation, we show that, unlike the other DNA polymerases belonging to the A, B, or Y family, DNA synthesis by Polι is severely inhibited by these N7-modified bases. These observations provide biochemical evidence that, during normal DNA synthesis, template purines adopt a
syn
conformation in the Polι active site, enabling the formation of a Hoogsteen base pair with the incoming pyrimidine nucleotide. Additionally, mutational studies with Leu-62, which lies in close proximity to the templating residue in the Polι ternary complex, have indicated that both factors, steric constraints within the active site and the stability provided by the hydrogen bonds in the Hoogsteen base pair, contribute to the efficiency of correct nucleotide incorporation opposite template purines by Polι.
Ephrin-B3 is a myelin-based inhibitor of neurite outgrowth
Authors: Benson M. Douglas , Romero Mario I. , Lush Mark E. , Lu Q. Richard , Henkemeyer Mark , Parada Luis F.
Published: July 2005

The inability of CNS axons to regenerate after traumatic spinal cord injury is due, in part, to the inhibitory effects of myelin. The three major previously identified constituents of this activity (Nogo, myelin-associated glycoprotein, and oligodendrocyte myelin glycoprotein) were isolated based on their potent inhibition of axon outgrowth
in vitro
. All three myelin components transduce their inhibitory signals through the same Nogo receptor/p75 neurotrophin receptor/LINGO-1 (NgR1/p75/LINGO-1) complex. In this study, we considered that molecules known to act as repellants in vertebrate embryonic axonal pathfinding may also inhibit regeneration. In mice, ephrin-B3 functions during development as a midline repellant for axons of the corticospinal tract. We therefore investigated whether this repellant was expressed in the adult spinal cord and retained inhibitory activity. We demonstrate that ephrin-B3 is expressed in postnatal myelinating oligodendrocytes and, by using primary CNS neurons, show that ephrin-B3 accounts for an inhibitory activity equivalent to that of the other three myelin-based inhibitors, acting through p75, combined. Our data describe a known vertebrate axon guidance molecule as a myelin-based inhibitor of neurite outgrowth.
Iodine content of salt 2 years after the introduction of the universal salt iodisation legislation in Lesotho
Authors: Damane Sebotsa Masekonyela Linono , Dannhauser Andre , Jooste Pieter L. , Joubert Gina
Published: July 2005

The aim of the present study was to assess the impact of the universal salt iodisation legislation on I levels of salt at household, retail and entry level in Lesotho. We used a multistage proportion to population size method to select thirty-one clusters from all the districts and ecological zones of Lesotho. In each cluster, thirty households were randomly selected and salt samples were collected. Six salt samples from two randomly selected retailers in each cluster, and a total of 107 salt samples from all the commercial entry points in the country were also collected. Lesotho does not produce salt and it imports almost all its salt from South Africa. The salt samples were analysed using the iodometric titration method. The median I concentration of salt was 36.2 ppm at entry point, 37·3 ppm at retail level and 38·5 ppm at household level. At household level only 1·6 % used non-iodised salt and 86·9 % used adequately iodised salt. Of all salt collected at household level, 20·4 % was coarse salt, which was significantly less well iodised than fine salt. The study demonstrates a major achievement in the availability of iodised salt as well as household use of adequately iodised salt. Under-iodisation of coarse salt and non-uniformity of salt iodisation at the production site were observed. Therefore, there is a need for enforcement of the salt iodisation legislation especially at entry-point level to ensure that only iodised salt enters the country. During enforcement more emphasis should be given to iodisation of coarse salt.
Should yoghurt cultures be considered probiotic?
Authors: Guarner Francisco , Perdigon Gabriela , Corthier Gérard , Salminen Seppo , Koletzko Berthold , Morelli Lorenzo
Published: July 2005

Probiotics are live micro-organisms that when administered in adequate amounts confer a health benefit on the host. Consumption of yoghurt has been shown to induce measurable health benefits linked to the presence of live bacteria. A number of human studies have clearly demonstrated that yoghurt containing viable bacteria (Streptococcus thermophilusandLactobacillus delbrueckiisp.bulgaricus) improves lactose digestion and eliminates symptoms of lactose intolerance. Thus, these cultures clearly fulfil the current concept of probiotics.
Problems of nutritional assessment in the community
Authors: Edington Jacqueline
Published: July 2005

The present paper explores the problems associated with assessment of nutritional status in the community and reviews the literature related to this subject. The first problem is one of terminology, since a logical first step before assessment is screening, which identifies characteristics known to be associated with dietary or nutritional problems. Its purpose is to differentiate individuals who are at high nutritional risk or have poor nutritional status. There are certain factors which should alert the primary health care team to the fact that nutritional intake may be reduced and that risk of malnutrition is increased. These include disease condition, functional disabilities, inadequate or inappropriate food intake, poor dentition or difficulty swallowing, polypharmacy, alcoholism, depression, poor social circumstances or recent discharge from hospital. Patients suffering from these factors need to be identified so that screening becomes a routine part of their medical treatment. At-risk groups include the elderly, the chronically ill, those with cancer and neurological disorders, post-surgical patients and children with developmental disabilities. In the community, practice and community nurses see the majority of at-risk patients and should carry out screening. A number of screening tools have been developed for community use. Most are aimed at the elderly population, but there are others designed to assess nutritional risk in children with developmental disabilities and the general population. These are reviewed and problems of content and validity identified. Some problems associated with nutritional assessment are also reviewed.
Immune response during disease and recovery in the elderly
Authors: Lesourd Bruno
Published: July 2005

The present article reviews immune ageing and its relationship with nutritional ageing, with a particular insight into the influences of disease on both ageing processes. Immune ageing can be described primarily as the progressive appearance of immune dysregulations, mainly acquired immunity (mature: immature, naive: memory T lymphocyte subset decreases) leading to gradual increases in T-helper 2: T-helper 1 cells. This change is due initially to decreased thymic function, and later to accumulative antigen pressure over the lifespan. In contrast, innate immunity (macrophage functions) is preserved during the ageing process and in the elderly this leads to macrophage–lymphocyte dysequilibrium, which is particularly critical during on-going disease. Indeed, any disease induces long-lasting acute-phase reactions in aged patients and leads to body nutritional reserve (mainly protein) losses. Episodes of disease in the aged patient progressively deplete body nutritional reserves and lead to protein–energy malnutrition, undernutrition-associated immunodeficiency, and finally cachexia. Undernutrition is a common symptom in the elderly; protein-energy malnutrition is found in more than 50 % of hospitalized elderly patients and in most elderly diseased subjects. In addition, micronutrient deficit or low levels are common in home-living self-sufficient apparently-healthy elderly subjects. All these nutritional deficits induce decreased immune responses, and micronutrient deficits are now thought to be partly responsible for the decreased immune responses (immune ageing?) observed in the apparently-healthy elderly. Indeed, several studies have shown that micronutrient supplements induce increased immune responses in the healthy elderly. The progression of infectious diseases depends on immune responses and on nutritional status before the onset of illness in aged subjects. In addition, recovery depends on the intensity of acute-phase responses in the undernourished elderly. In fact, chronic acute-phase responses, commonly associated with diseases in aged patients, lead to progressive lowering of metabolic responses in the undernourished elderly. This can be quantified by increased production of free radicals during treatment and these increases may explain the difficulty in successfully treating aged patients. Nutritive therapy in order to improve metabolic processes and also to maintain body reserves should be considered as a necessary adjuvant therapy in the treatment of elderly patients.
Action-feature integration blinds to feature-overlapping perceptual events: Evidence from manual and vocal actions
Authors: Hommel Bernhard , Müsseler Jochen
Published: July 2005

Previous studies showed that the identification of a left- or right-pointing arrowhead is impaired when it appears while planning and executing a spatially compatible left or right keypress (Müsseler & Hommel, 1997a). We attribute this effect to stimulus processing and action control operating on the same feature codes so that, once a code is integrated in an action plan, it is less available for perceptual processing. In three pairs of experiments we tested the generality of this account by using stimulus–response combinations other than arrows and manual keypresses. Planning manual left–right keypressing actions impaired the identification of spatially corresponding arrows but not of words with congruent meaning. On the contrary, planning to say “left” or “right” impaired the identification of corresponding spatial words but not of congruent arrows. Thus, as the feature-integration approach suggests, stimulus identification is impaired only with overlap of perceptual or perceptually derived stimulus and response features while mere semantic congruence is insufficient.
SPEM: improving multiple sequence alignment with sequence profiles and predicted secondary structures
Authors: Zhou Hongyi , Zhou Yaoqi
Published: July 2005

Motivation: Multiple sequence alignment is an essential part of bioinformatics tools for a genome-scale study of genes and their evolution relations. However, making an accurate alignment between remote homologs is challenging. Here, we develop a method, called SPEM, that aligns multiple sequences using pre-processed sequence profiles and predicted secondary structures for pairwise alignment, consistency-based scoring for refinement of the pairwise alignment and a progressive algorithm for final multiple alignment.

Results: The alignment accuracy of SPEM is compared with those of established methods such as ClustalW, T-Coffee, MUSCLE, ProbCons and PRALINEPSI in easy (homologs) and hard (remote homologs) benchmarks. Results indicate that the average sum of pairwise alignment scores given by SPEM are 7–15% higher than those of the methods compared in aligning remote homologs (sequence identity <30%). Its accuracy for aligning homologs (sequence identity >30%) is statistically indistinguishable from those of the state-of-the-art techniques such as ProbCons or MUSCLE 6.0.

Availability: The SPEM server and its executables are available on http://theory.med.buffalo.edu

Contact:  yqzhou@buffalo.edu
A window on the genetics of evolution:MC1Rand plumage colouration in birds
Authors: Mundy Nicholas I
Published: July 2005

Melanins are a ubiquitous component of plumage colouration in birds and serve a wide variety of functions. Although the genetic control of melanism has been studied in chickens and other domestic species, little was known about the molecular genetics of melanin distribution in wild birds until recently. Studies have now revealed that a single locus, the melanocortin-1 receptor (MC1R) locus, is responsible for melanic polymorphisms in at least three unrelated species: the bananaquit, the snow goose and the arctic skua. Results show that melanism was a derived trait and allow other evolutionary inferences about the history of melanism to be made. The role ofMC1Rin plumage patterning is surprisingly diverse among different species. The conserved molecular basis for the evolution of melanism in birds and several other vertebrates is probably related to low pleiotropic effects at theMC1R.
Alternative life histories shape brain gene expression profiles in males of the same population
Authors: Aubin-Horth Nadia , Landry Christian R , Letcher Benjamin H , Hofmann Hans A
Published: July 2005

Atlantic salmon (
Salmo salar
) undergo spectacular marine migrations before homing to spawn in natal rivers. However, males that grow fastest early in life can adopt an alternative ‘sneaker’ tactic by maturing earlier at greatly reduced size without leaving freshwater. While the ultimate evolutionary causes have been well studied, virtually nothing is known about the molecular bases of this developmental plasticity. We investigate the nature and extent of coordinated molecular changes that accompany such a fundamental transformation by comparing the brain transcription profiles of wild mature sneaker males to age-matched immature males (future large anadromous males) and immature females. Of the
ca.
3000 genes surveyed, 15% are differentially expressed in the brains of the two male types. These genes are involved in a wide range of processes, including growth, reproduction and neural plasticity. Interestingly, despite the potential for wide variation in gene expression profiles among individuals sampled in nature, consistent patterns of gene expression were found for individuals of the same reproductive tactic. Notably, gene expression patterns in immature males were different both from immature females and sneakers, indicating that delayed maturation and sea migration by immature males, the ‘default’ life cycle, may actually result from an active inhibition of development into a sneaker.
The hidden cost of information in collective foraging
Authors: Dechaume-Moncharmont François-Xavier , Dornhaus Anna , Houston Alasdair I , McNamara John M , Collins Edmund J , Franks Nigel R
Published: July 2005

Many animals nest or roost colonially. At the start of a potential foraging period, they may set out independently or await information from returning foragers. When should such individuals act independently and when should they wait for information? In a social insect colony, for example, information transfer may greatly increase a recruit's probability of finding food, and it is commonly assumed that this will always increase the colony's net energy gain. We test this assumption with a mathematical model. Energy gain by a colony is a function both of the probability of finding food sources and of the duration of their availability. A key factor is the ratio of pro-active foragers to re-active foragers. When leaving the nest, pro-active foragers search for food independently, whereas re-active foragers rely on information from successful foragers to find food. Under certain conditions, the optimum strategy is totally independent (pro-active) foraging because potentially valuable information that re-active foragers may gain from successful foragers is not worth waiting for. This counter-intuitive outcome is remarkably robust over a wide range of parameters. It occurs because food sources are only available for a limited period. Our study emphasizes the importance of time constraints and the analysis of dynamics, not just steady states, to understand social insect foraging.
Females solicit sneakers to improve fertilization success in the bitterling fish (
Rhodeus sericeus
)
Authors: Smith Carl , Reichard Martin
Published: July 2005

In most species there is greater variance in reproductive fitness among males than females. A consequence is the evolution of alternative male mating tactics, including sneaking behaviour whereby males attempt to mate with females courted by other males, which could undermine female choice. In bitterling (
Rhodeus sericeus
), fish that lay their eggs on the gills of living freshwater mussels, sneaking is common and successful. Here we show that female bitterling can significantly improve their fertility with an increase in the number of spawning partners. Females perform conspicuous behaviours associated with spawning more frequently close to sneakers, and spawn more eggs close to high-quality sneakers. This is the first time that females have been shown to engage in behaviour that increases the probability of sneaking, and raises the possibility of a sexual conflict over the number and source of ejaculates during spawning in this species.
The loss of anti-predator behaviour following isolation on islands
Authors: Blumstein Daniel T , Daniel Janice C
Published: July 2005

When isolated from predators, costly and no longer functional anti-predator behaviour should be selected against. Predator naiveté is often pronounced on islands, where species are found with few or no predators. However, isolation on islands involves other processes, such as founder effects, that might be responsible for naiveté or reduced anti-predator behaviour. We report the first comparative evidence that, in macropodid marsupials, isolation on islands may lead to a systematic loss of ‘group size effects’—a behaviour whereby individuals reduce anti-predator vigilance and allocate more time to foraging as group size increases. Moreover, insular animals forage more, and are less vigilant, than mainland ones. However, we found no evidence that animals on the mainland are ‘flightier’ than those on islands. Remarkably, we also found no evidence that isolation from all predatorsper seis responsible for these effects. Together, these results demonstrate that anti-predator behaviour may indeed be lost or modified when animals are isolated on islands, but it is premature to assume that all such behaviour is affected.
Biomass recycling and the origin of phenotype in fungal mycelia
Authors: Falconer Ruth E , Bown James L , White Nia A , Crawford John W
Published: July 2005

Fungi are one of the most important and widespread components of the biosphere, and are essential for the growth of over 90% of all vascular plants. Although they are a separate kingdom of life, we know relatively little about the origins of their ubiquitous existence. This reflects a wider ignorance arising from their status as indeterminate organisms epitomized by extreme phenotypic plasticity that is essential for survival in complex environments. Here we show that the fungal phenotype may have its origins in the defining characteristic of indeterminate organisms, namely their ability to recycle locally immobilized internal resources into a mobilized form capable of being directed to new internal sinks. We show that phenotype can be modelled as an emergent phenomenon resulting from the interplay between simple local processes governing uptake and remobilization of internal resources, and macroscopic processes associated with their transport. Observed complex growth forms are reproduced and the sensitive dependence of phenotype on environmental context may be understood in terms of nonlinearities associated with regulation of the recycling apparatus.
Imitation dynamics predict vaccinating behaviour
Authors: Bauch Chris T
Published: July 2005

There exists an interplay between vaccine coverage, disease prevalence and the vaccinating behaviour of individuals. Moreover, because of herd immunity, there is also a strategic interaction between individuals when they are deciding whether or not to vaccinate, because the probability that an individual becomes infected depends upon how many other individuals are vaccinated. To understand this potentially complex interplay, a game dynamic model is developed in which individuals adopt strategies according to an imitation dynamic (a learning process), and base vaccination decisions on disease prevalence and perceived risks of vaccines and disease. The model predicts that oscillations in vaccine uptake are more likely in populations where individuals imitate others more readily or where vaccinating behaviour is more sensitive to changes in disease prevalence. Oscillations are also more likely when the perceived risk of vaccines is high. The model reproduces salient features of the time evolution of vaccine uptake and disease prevalence during the whole-cell pertussis vaccine scare in England and Wales during the 1970s. This suggests that using game theoretical models to predict, and even manage, the population dynamics of vaccinating behaviour may be feasible.
Constitutive innate immunity is a component of the pace-of-life syndrome in tropical birds
Authors: Irene Tieleman B , Williams Joseph B , Ricklefs Robert E , Klasing Kirk C
Published: July 2005

We studied the relationship between one component of immune function and basal metabolic rate (BMR), an indicator of the ‘pace-of-life syndrome’, among 12 tropical bird species and among individuals of the tropical house wren (Troglodytes aedon), to gain insights into functional connections between life history and physiology. To assess constitutive innate immunity we introduced a new technique in the field of ecological and evolutionary immunology that quantifies the bactericidal activity of whole blood. Thisin vitroassay utilises a single blood sample to provide a functional, integrated measure of constitutive innate immunity. We found that the bactericidal activity of whole blood varied considerably among species and among individuals within a species. This variation was not correlated with body mass or whole-organism BMR. However, among species, bacteria killing activity was negatively correlated with mass-adjusted BMR, suggesting that species with a slower pace-of-life have evolved a more robust constitutive innate immune capability. Among individuals of a single species, the house wren, bacteria killing activity was positively correlated with mass-adjusted BMR, pointing to physiological differences in individual quality on which natural selection potentially could act.
Notch signaling regulates the differentiation of post-mitotic intestinal epithelial cells
Authors: Zecchini Vincent , Domaschenz Renae , Winton Doug , Jones Phil
Published: July 2005

The intestinal epithelium comprises differentiated cells of four lineages maintained by precursor cells. As the Notch pathway controls the fate of proliferating cells in many systems, we investigated the effect of conditional expression of an activated Notch mutant in intestinal epithelium. An increase in the number of goblet cells occurs within 8 h of induction, due to an effect of Notch on post-mitotic cells, not on precursors. This observation broadens the role of Notch into controlling postmitotic differentiation and indicates that the composition of the epithelium is not solely determined by progenitor cells.
Consumer perceptions of food safety education sources
Authors: Redmond Elizabeth C. , Griffith Christopher J.
Published: July 2005

Purpose

Consumers often use inappropriate food‐handling practices and improving these could help to reduce the incidence of foodborne disease. However the development of an effective food safety education strategy is considered complex and could be improved by having a greater understanding of the consumer. This paper proposes investigating the modes and channels of communication that maybe used in education strategies.

Design/methodology/approach

A self‐complete postal questionnaire was distributed to a linked demographic quota of adults in South Wales. Responses were entered into a specially constructed food safety database.

Findings

Results indicated that the Environmental Health departments and UK Food Standards Agency were perceived to be the most trusted and credible organisations that can provide food safety information. The most believable spokespersons for promotion of food safety advice were determined as Environmental Health officers and the Chief Medical Officer. The most preferred source of food safety information identified were food packaging, followed by advice from a medical doctor.

Research limitations/implications

Although only a relatively small sample size, many of the findings have been corroborated by qualitative data from nationwide focus groups. The data have been used as the precursor for a large nationwide study of over 2,000 consumers and this should further validate the data.

Originality/value

The results will be of benefit to a range of organisations currently engaged in food safety education as well as identifying potentially underutilised channels of communication.
Understanding consumer perception of food quality: the cases of shrimps and cheese
Authors: Hansen Torben
Published: July 2005

Purpose

The paper proposes to investigate empirically consumers' quality perception of shrimps and cheese.

Design/methodology/approach

A sample of 320 respondents was included in an experimental design in which two food products, shrimps and cheese, two price‐levels, two levels of purchase involvement, and two types of physical surroundings, elegant and less elegant, were manipulated. The experiments included both simulated buying situations and simulated usage situations.

Findings

The research finds that in the buying situation both experiments perceived price had a positive effect on expected eating quality for high‐involved respondents but not for low‐involved respondents. In the usage situation the effect of expected naturalness on experienced naturalness was in both experiments stronger for high‐involved respondents than for low‐involved respondents. In addition, experienced eating quality positively affected respondents' pleasure‐feeling. The positive effect of experienced eating quality on pleasure‐feeling was stronger for respondents exposed to elegant physical surroundings than for respondents exposed to less elegant surroundings.

Research limitations/implications

This research concentrated on analyzing two food products, fresh‐shelled shrimps and solid cheese. This could mean that the results may suffer from a lack of generalizability. A large cross‐section of products ought to be studied to improve the generalizability of the results. Also, the manipulation of price and physical surroundings were confined to two different levels. Thus, this research offers no specific guidelines on how to set specific prices or how to establish specific physical surroundings for the purpose of manipulating, e.g. consumers' perceived quality.

Practical implications

The results emphasize that food producers and retailers, among others, should seek an understanding of consumers' quality perception process in relation to both the buying and the usage situation.

Originality/value

This paper empirically investigates consumers' quality perception in both buying and usage situations. Also, the paper includes purchase involvement and physical surroundings as moderating variables of the quality perception process.
Food storage and disposal: consumer practices and knowledge
Authors: Terpstra M.J. , Steenbekkers L.P.A. , de Maertelaere N.C.M. , Nijhuis S.
Published: July 2005

Purpose

Consumer food handling behaviour is important in preventing food borne disease and this paper proposes examining consumer behaviour and knowledge concerning food storage and disposal.

Design/methodology/approach

Interviews and observations were used to investigate the storage methods and the storage durations of various categories of food products as well as the consumers' motives when they decide to throw away food products. The temperature of their refrigerators was also measured.

Findings

The results demonstrate that consumers deal with meat and dairy products relatively hygienically, but the storage of products in other categories is more likely to lead to risks; especially because of high storage temperatures. The study also shows that the elderly handle food differently from younger people.

Research limitations/implications

Knowledge of the recommended storage methods and the consequences of consuming out‐of‐date foodstuffs have not been investigated. This could be dealt with in a supplemental research.

Practical implications

The elderly have a different purchasing policy. The older consumer of the future is likely to act differently to the present day elderly with respect to the disposal of food products.

Originality/value

Reveals that consumer education about food safety, in particular food storage and food handling is recommended.
Wage differentials in the 1990s in Israel: endowments, discrimination, and selectivity
Authors: Neuman Shoshana , Oaxaca Ronald L.
Published: July 2005

Purpose

To examine gender and ethnic wage structures and wage differentials an Israel and decompose the difference in wages into endowments, discrimination and selectivity components.

Design/methodology/approach

Selection and wage equations are estimated for each of the population groups (Eastern women, Western women, Eastern men, Western men) separately. The wage equations are corrected for selectivity using the Heckman procedure and subsequently wage differentials are decomposed into the three components mentioned above, using four alternative decompositions suggested in 2004 by Neuman and Oaxaca.

Findings

Gender wage differentials are significantly larger than ethnic differences. Discrimination is more common between the genders. The four alternative decompositions – that are based on different assumptions and objectives – yield different results.

Research limitations/implications

Decomposition of wage differences between groups needs to take into account information on the local relevant labor market and the wage setting process.

Practical implications

Information on the relative shares of the endowments, discrimination and selectivity components leads to a more effective way to close wage gaps.

Originality/value

Employment of new proposed decomposition methodologies that might lead to practical implications to combat gender and ethnic wage gaps in Israel.