bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulmonary rehabilitation
Authors: Dutta Dipankar , Butland Richard JA , Dutta Ruma R , Casey Miriam C
Published: July 2004

Pulmonary rehabilitation is a multidisciplinary education and exercise programme of care for patients with chronic respiratory disease, particularly Chronic Obstructive Pulmonary Disease (COPD). It aims to reduce symptoms, decrease disability, increase participation in physical and social activities and improve overall quality of life in patients who may still be very disabled despite optimal pharmacological treatment. Pulmonary rehabilitation first began more than 30 years ago and is now established as an important part of the management of COPD.
Fear of falling: links between imbalance and anxiety
Authors: Yardley Lucy
Published: July 2004

This review examines the relationship between unsteadiness, falling and anxiety, and their combined impact on the lives of older people. Over one in four people over 69 fall each year, and a higher proportion of those over 74. Although only one in ten incur serious injury as a direct result of the fall, fear of falling can often lead not only to psychological distress but also to restriction of activity and an unnecessary and undesirable loss of independence. Naturally, symptoms of unsteadiness constitute a key risk factor for falling. As many as one in three older people have suffered from unsteadiness and/or dizziness at some time. Like falling, dizziness and unsteadiness are also associated with distress and restriction of activity.
Inequalities in the incidence and management of, and outcome from, neurological diseases in older people
Authors: Macleod Malcolm
Published: July 2004

The publication of the Black Report in 1980 is rightly seen as a landmark in the acknowledgement of an association between poverty and increased incidence of and premature mortality from a wide range of diseases. However, an increased incidence of disease with certain lifestyles or habits has been recognized since the time of Hippocrates, who identified ‘the mode in which inhabitants live, and what are their pursuits, whether they are fond of drinking and eating in excess’ as determinants of illness.
Rehabilitation in Parkinson's disease
Authors: Ward Christopher D , Robertson Dorothy
Published: July 2004

Rehabilitation can be described either as a set of technologies, akin to drug treatment, or as a person-centered process. We will use both frames of reference in this review. Our orientation in Part 1 will be technological, with initial consideration of the pathophysiology of parkinsonian impairments, before examining the rationale for non-drug interventions in Parkinson's disease (PD). In Part 2 we describe how the process of rehabilitation can be applied in a progressive disease such as PD.
Health and aging: does retirement transition make any difference?
Authors: Fonseca António M. , Paúl Constança
Published: July 2004

A basic notion relating to development during adulthood and old age, according to a lifespan perspective, refers to the progressive increase in individual differences in psychological wellbeing. It is possible to find diverse ‘health trajectories’, shaping patterns of evolution regarding the general health of adult and elderly individuals, such as (1) permanent good health (2) good health most of the time and decline by the end of life (3) health decline and recovery (4) permanent poor health, (5) progressive decline and (6) irregular health.
Correlation Structure of Landscapes of NP-Complete Optimization Problems at Finite Temperatures
Authors: Gehring Wolfgang , Salamon Peter , Whitney Roger E. , Sibani Paolo
Published: July 2004

We analyze the autocorrelation function of a time series of energy values sampled in the energy landscapes of four different combinatorial optimization problems by a Metropolis random walk. The temperature of the walk and the size of the investigated problems are systematically varied. We find that, in a suitably defined high temperature region the autocorrelation decays in an exponential fashion. We extract the temperature and system size dependence of the corresponding correlation time, which turns out to be of the Arrhenius form. Energetic and entropic contributions to the correlation time (barriers) are identified and shown to be asymptotically independent of system size.
Effects of Task Instructions on Visual Field Language Asymmetries
Authors: Taylor Kirsten I. , Brugger Peter , Weniger Dorothea , Regard Marianne
Published: July 2004

Abstract: Lexical decision tasks (LDTs) are often employed to implicitly measure each hemisphere's capacity to process semantic information. Different hemispheric patterns may result from tasks with explicit semantic demands (semantic decision tasks, SDTs). We administered healthy subjects two different lateralized tasks, one LDT and one SDT (category matching task). The target word pairs were identical in both tasks and either closely or distantly semantically related. Overall, the fastest RTs were evidenced in the RVF/LH. However, individual analyses revealed a single main effect of hemifield in the LDT (RVF/LH faster than LVF/RH) and a single main effect of semantic distance (shorter latencies with closely related words) in the SDT. These findings indicate that hemispheric asymmetries depend on task demands.
Quantitative modeling of the magnetic field configuration associated with the theta aurora
Authors: Naehr S. M. , Toffoletto F. R.
Published: July 2004

The relationships among the interplanetary magnetic field (IMF), the global magnetospheric configuration, and the polar cap configuration known as the theta aurora are explored, using simulations generated by the Rice Field Model and the BATSRUS global MHD model. Two phenomena that have been linked to theta auroras are examined: a “convection gap,” or region of zero magnetic normal component on the magnetopause, associated with antiparallel merging during periods of steady, predominantly northward IMF, and a reconfiguration of the tail lobe and plasma sheet twist following abrupt IMF rotations. It is found that (1) the convection gap does not produce configurations consistent with the theta aurora, (2) large‐angle rotations of the IMF produce partial bifurcations of the open‐closed boundary and tail lobes and field‐aligned current patterns that are consistent with the theta aurora, (3) reconfiguration of the plasma sheet during IMF rotations, rather than relocation of the merging line, is critical to the development of theta aurora‐like configurations, (4) a sufficient magnetotail length, longer than produced in MHD simulations but consistent with the Rice Field Model, can account for the observed duration and velocity of theta auroras created by a single IMF rotation, (5) multiple IMF rotations do not significantly affect the duration of the theta configuration but may lead to multiple transpolar arcs.
Energetic magnetospheric oxygen in the magnetosheath and its response to IMF orientation: Cluster observations
Authors: Marcucci M. F. , Bavassano Cattaneo M. B. , Pallocchia G. , Amata E. , Bruno R. , Di Lellis A. M. , Formisano V. , Rème H. , Bosqued J. M. , Dandouras I. , Sauvaud J.‐A. , Kistler L. M. , Moebius E. , Klecker B. , Carlson C. W. , Parks G. K. , McCarthy M. , Korth A. , Lundin R. , Balogh A.
Published: July 2004

We present Cluster observations made during an outbound orbit on 10 December 2000. After exiting the magnetosphere at midlatitude, Cluster spent a long time skimming the magnetopause moving to lower latitude along an orbit approximately in the ZYGSM plane on the dusk flank of the magnetopause. During this time, magnetospheric oxygen with energy ≥10 keV was observed continuously both in the magnetosphere and in the magnetosheath by the Cluster Ion Spectrometry (CIS) plasma experiment. While the oxygen density is roughly constant in the magnetosheath throughout the event, its velocity shows a strong dependence on the magnetosheath magnetic field orientation: low speeds, corresponding to almost isotropic distribution functions, occur for northward magnetic field, and high speeds, corresponding to “beam‐like” distribution function occur for southward magnetic field. Mainly, two different processes have been discussed to explain the energetic particles escaping from the magnetosphere: flow along reconnected magnetospheric and magnetosheath field lines or crossing of the magnetopause when the particle gyroradii are comparable with the magnetopause thickness. The presence of the oxygen population cannot be readily explained in the framework of the reconnection theory. Instead, the observations are successfully reproduced by a model based on magnetopause crossing by finite gyroradius, provided the magnetosheath convection is taken into account together with the magnetosheath magnetic field orientation. Moreover, the presence of quasi‐periodic motion of the magnetopause surface with period of approximately 5 min are evidenced by the analysis.
Bioinformatic approaches for objective detection of water masses on continental shelves
Authors: Oliver Matthew J. , Glenn Scott , Kohut Josh T. , Irwin Andrew J. , Schofield Oscar M. , Moline Mark A. , Bissett W. Paul
Published: July 2004

As part of the 2001 Hyper Spectral Coupled Ocean Dynamics Experiment, sea surface temperature and ocean color satellite imagery were collected for the continental shelf of the Mid‐Atlantic Bight. These images were used to develop a water mass analysis and classification scheme that objectively describes the locations of water masses and their boundary locations. This technique combines multivariate cluster analysis with a newly developed genetic expression algorithm to objectively determine the number of water types in the region on the basis of ocean color and sea surface temperature measurements. Then, through boundary analysis of the water types identified, the boundaries of the major water types were mapped and the differences between them were quantified using predictor space distances. Results suggest that this approach can track the development and transport of water masses. Because the analysis combines the information of multiple predictors to describe water masses, it is an effective tool in detecting water masses not readily recognizable with temperature or chlorophyll alone.
A comparison of similar aerosol measurements made on the NASA P3‐B, DC‐8, and NSF C‐130 aircraft during TRACE‐P and ACE‐Asia
Authors: Moore K. G. , Clarke A. D. , Kapustin V. N. , McNaughton C. , Anderson B. E. , Winstead E. L. , Weber R. , Ma Y. , Lee Y. N. , Talbot R. , Dibb J. , Anderson T. , Doherty S. , Covert D. , Rogers D.
Published: July 2004

Two major aircraft experiments occurred off the Pacific coast of Asia during spring 2001: the NASA sponsored Transport and Chemical Evolution over the Pacific (TRACE‐P) and the National Science Foundation (NSF) sponsored Aerosol Characterization Experiment‐Asia (ACE‐Asia). Both experiments studied emissions from the Asian continent (biomass burning, urban/industrial pollution, and dust). TRACE‐P focused on trace gases and aerosol during March/April and was based primarily in Hong Kong and Yokota Air Force Base, Japan, and involved two aircraft: the NASA DC‐8 and the NASA P3‐B. ACE‐Asia focused on aerosol and radiation during April/May and was based in Iwakuni Marine Corps Air Station, Japan, and involved the NSF C‐130. This paper compares aerosol measurements from these aircraft including aerosol concentrations, size distributions (and integral properties), chemistry, and optical properties. Best overall agreement (generally within RMS instrumental uncertainty) was for physical properties of the submircron aerosol, including condensation nuclei concentrations, scattering coefficients, and differential mobility analyzer and optical particle counter (OPC) accumulation mode size distributions. Larger differences (typically outside of the RMS uncertainty) were often observed for parameters related to the supermicron aerosols (total scattering and absorption coefficients, coarse mode Forward Scattering Spectrometer Probe and OPC size distributions/integral properties, and soluble chemical species usually associated with the largest particles, e.g., Na+, Cl−, Ca2+, and Mg2+), where aircraft sampling is more demanding. Some of the observed differences reflect different inlets (e.g., low‐turbulence inlet enhancement of coarse mode aerosol), differences in sampling lines, and instrument configuration and design. Means and variances of comparable measurements for horizontal legs were calculated, and regression analyses were performed for each platform and allow for an assessment of instrument performance. These results provide a basis for integrating aerosol data from these aircraft platforms for both the TRACE‐P and ACE‐Asia experiments.
Prelaunch performance evaluation of the cometary experiment MUPUS‐TP
Authors: Marczewski W. , Schröer K. , Seiferlin K. , Usowicz B. , Banaszkiewicz M. , Hlond M. , Grygorczuk J. , Gadomski S. , Krasowski J. , Gregorczyk W. , Kargl G. , Hagermann A. , Ball A. J. , Kührt E. , Knollenberg J. , Spohn T.
Published: July 2004

This paper discusses test results obtained in both laboratory and terrestrial environment conditions for the “Multipurpose Sensors for Surface and Sub‐Surface Science” Thermal Probe (MUPUS‐TP), which has been developed for the European Space Agency Rosetta cometary rendezvous mission. The probe is intended to provide in situ long‐term observations of the thermal evolution of the comet nucleus and will measure a thermal conductivity profile with time in the top 30 cm of the comet nucleus. The basic operating principles of the probe are briefly described, including typical test results gathered in terrestrial snow and soil. The tests in snow provide verification of the probe as a useful tool for monitoring the metamorphism of snow on the Earth. The tests in soil are intended to demonstrate the probe's suitability as an alternative to other methods of energy measurement currently practiced in soil physics research. The tests of the probe in the natural environment of the Earth provide a demonstration of the behavior of the instrument in the presence of complex energy exchange processes before it is used on the comet.
Huygens' Principle: The capture of seismic energy by a soft soil layer
Authors: Lomnitz Cinna , Meas Yunny
Published: July 2004

Possible nonlinear coupling in surface waves is described at the Texcoco Array (TXC) in Mexico City. Shear‐coupled surface waves may be caused by interaction between Rayleigh modes in the basement and resonant shear modes in the uppermost mud layer. Large‐amplitude, monochromatic wave trains of long duration appear to be modulated by the fundamental mode of the mud layer. Particle motion features frequent reversals from prograde to retrograde ground motion. Earthquake damage in Mexico City might be related to unrecognized effects related to nonlinear coupling in soft‐soil conditions.
The Drinfeld realization of the elliptic quantum group Bq,λ(A2(2))
Authors: Kojima Takeo , Konno Hitoshi
Published: July 2004

We construct a realization of the L-operator satisfying the RLL-relation of the face-type elliptic quantum group Bq,λ(A2(2)). The construction is based on the elliptic analog of the Drinfeld currents of Uq(A2(2)), which forms the elliptic algebra Uq,p(A2(2)). We give a realization of the elliptic currents E(z), F(z), and K(z) as a tensor product of the Drinfeld currents of Uq(A2(2)) and a Heisenberg algebra. In the level-one representation, we also give a free field realization of the elliptic currents. Applying these results, we derive a free field realization of the Uq,p(A2(2))-analog of the Bq,λ(A2(2))-intertwining operators. The resultant operators coincide with those of the vertex operators in the dilute AL model, which is known to be a RSOS restriction of the A2(2) face model.
Minimization under entropy conditions, with applications in lower bound problems
Authors: Toft Joachim
Published: July 2004

We minimize the functional f⟼∫ afdμ under the entropy condition E(f)=−∫ f log fdμ⩾E, ∫ fdμ=1 and f⩾0, where E∈R is fixed. We prove that the minimum is attained for f=e−sa/∫ e−sadμ, where s∈R is chosen such that E(f)=E. We apply the result on minimizing problems in pseudodifferential calculus, where we minimize the harmonic oscillator.
Yang–Mills instantons with Lorentz violation
Authors: Colladay Don , McDonald Patrick
Published: July 2004

An analysis is performed of instanton configurations in pure Euclidean Yang–Mills theory containing small Lorentz-violating perturbations that maintain gauge invariance. Conventional topological arguments are used to show that the general classification of instanton solutions involving the topological charge is the same as in the standard case. Explicit solutions are constructed for general gauge invariant corrections to the action that are quadratic in the curvature. The value of the action is found to be unperturbed to lowest order in the Lorentz-violating parameters.
Partially invariant solutions of models obtained from the Nambu–Goto action
Authors: Grundland A. M. , Hariton A. J.
Published: July 2004

The concept of partially invariant solutions is discussed in the framework of the group analysis of models derived from the Nambu–Goto action. In particular, we consider the nonrelativistic Chaplygin gas and the relativistic Born–Infeld theory for a scalar field. Using a general systematic approach based on subgroup classification methods, nontrivial partially invariant solutions with defect structure δ=1 are constructed. For this purpose, a classification of the subgroups of the Lie point symmetry group, which have generic orbits of dimension 2, has been performed. These subgroups allow us to introduce the corresponding symmetry variables and next to reduce the initial equations to different nonequivalent classes of partial differential equations and ordinary differential equations. The latter can be transformed to standard form and, in some cases, solved in terms of elementary and Jacobi elliptic functions. This results in a large number of new partially invariant solutions, which are determined to be either reducible or irreducible with respect to the symmetry group. Some physical interpretation of the results in the area of fluid dynamics and field theory are discussed. The solutions represent traveling and centered waves, algebraic solitons, kinks, bumps, cnoidal and snoidal waves.
Quantum doubles from a class of noncocommutative weak Hopf algebras
Authors: Li Fang , Zhang Yao-Zhong
Published: July 2004

The concept of biperfect (noncocommutative) weak Hopf algebras is introduced and their properties are discussed. A new type of quasi-bicrossed products is constructed by means of weak Hopf skew-pairs of the weak Hopf algebras which are generalizations of the Hopf pairs introduced by Takeuchi. As a special case, the quantum double of a finite dimensional biperfect (noncocommutative) weak Hopf algebra is built. Examples of quantum doubles from a Clifford monoid as well as a noncommutative and noncocommutative weak Hopf algebra are given, generalizing quantum doubles from a group and a noncommutative and noncocommutative Hopf algebra, respectively. Moreover, some characterizations of quantum doubles of finite dimensional biperfect weak Hopf algebras are obtained.
Effects of pasture species mixture, management, and environment on the productivity and persistence of dairy pastures in south-west Victoria. 1. Herbage accumulation and seasonal growth pattern
Authors: Nie Z. N. , Chapman D. F. , Tharmaraj J. , Clements R.
Published: July 2004

An experiment was conducted on 2 contrasting soil types for 4 years (1998–2001) to determine the effects of plant species mixture, management inputs, and environment on sown species herbage accumulation (SSHA) and seasonal growth pattern of pastures for dairy production. Five pasture types, combined with 3 management treatments, were established in south-west Victoria. Three of the pasture types were based on perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.). One pasture type included short-term, winter- or summer-active species in the perennial ryegrass–white clover mixture. The final pasture type was based on the perennial grasses cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), and phalaris (Phalaris aquatica L.). The 3 management treatments involved different levels of fertiliser input and weed/pest control. Pasture type had a significant impact on SSHA in 3 of 4 years. In the first year, the mixture based on cocksfoot, tall fescue, and phalaris had the lowest SSHA, but this pasture matched other types from 1999 onwards and yielded the highest in 2000, the year with the driest summer during the experiment. Ryegrass–white clover mixture based on old cultivars had generally lower SSHA than the other types except in the first year. Higher fertiliser inputs increased SSHA by 16–28% in 1998, 1999, and 2001. There was a significant site × pasture type interaction on SSHA in 2000. The mixture based on cocksfoot, tall fescue, and phalaris produced up to 1–2 t DM/ha.year more than the other types in summer and autumn in dry–normal years. The inclusion of short-term species, or more stoloniferous white clover cultivars, in the ryegrass–white clover mixture, had little effect on SSHA, or on the seasonal distribution of pasture growth. Pastures based on perennial grasses other than perennial ryegrass appear to have potential for altering the seasonality of pasture growth in south-west Victoria, although the benefits resulting from changing pasture type will depend on environment. Overall, increasing management inputs usually had a greater effect on SSHA than changing pasture type, but management responses were also affected by environment, particularly through the effects of a dry season on a sandy soil type.
Improving Fiji disease resistance screening trials in sugarcane by considering virus transmission class and possible origin of Fiji disease virus
Authors: Smith Grant R. , Candy Judith M.
Published: July 2004

Fiji disease virus is a propagative, persistently transmitted virus that multiplies in species of the delphacid planthopper genus Perkinsiella, and in sugarcane, the feeding host of the insect. Efforts to improve and modify the disease rating system for Fiji disease have largely focussed on the planthopper as individual vectors of the virus, rather than as a population of the principal, or at least an alternative, host of the virus. This perspective has resulted in key parameters of disease incidence resulting from plant infection by propagative, persistently transmitted viruses being largely overlooked or misunderstood during efforts to improve the rating system. These parameters include the relatively long acquisition, latency, and transmission times, the percentage of the population containing virus, or viruliferous, in the above periods, and the effects of population density and number of plants visited on disease incidence. Suggestions to modify trial design to improve virus transmission to the plant, based on the disease incidence parameters of the propagative, persistent transmission class, are presented and the practical difficulties of implementing these proposals are discussed. In the context of fully understanding the underlying biology of this virus–insect–plant system, the hypothesis that Fiji disease virus, as a plant-infecting member of the Reoviridae, is primarily an insect virus with a secondary plant host, and may have diverged from an insect-infecting virus relatively recently is proposed and compared with other members of the family Reoviridae.
Genetic polymorphisms in porcine leptin gene and their association with reproduction and production traits
Authors: Chen Chi-Chen , Chang Tse , Su Hung-Yi
Published: July 2004

Leptin (LEP), the product of the leptin gene, is a 16-kDa protein synthesised by adipose tissue and is involved in regulation of feed intake, energy balance, fertility, and immune functions. Using bi-directional polymerase chain reaction amplification of specific alleles (bi-PASA) and PCR-restriction fragment length polymorphisms (PCR-RFLP), we have successfully detected genetic polymorphisms of LEP intron 1 and exon 3, respectively, in Landrace, Yorkshire, and Duroc. Chi-square statistics were used to calculate homogeneity of genotypic frequencies of 2 candidate genes for 3 breeds of animals. Effects of exon 3 polymorphisms on reproduction traits such as litter sizes of sows in the first parity and 1–4 parities were evident (P < 0.05) in Landrace, and 1–4 parities in Yorkshire. Polymorphisms of intron 1 affected (P < 0.05) only litter sizes of the first parity in Duroc. Effects of exon 3 polymorphisms on production traits such as average daily gain and feed efficiency were evident (P < 0.05) in Landrace and Yorkshire, respectively. Polymorphisms of intron 1 affected (P < 0.05) only backfat thickness in Duroc. Our data also show that the higher the reproduction traits, the lower the genotypic frequencies. Further, the better the production traits, the higher the genotypic frequencies were. These data suggest that the long-term selection of favourable traits in pig production may be partially attributed to the effects of LEP polymorphisms on reproduction and production traits.
Host Defence Peptides from the Skin Glands of Australian Amphibians. Caerulein Neuropeptides and Antimicrobial, Anticancer, and nNOS Inhibiting Citropins from the Glandular Frog Litoria subglandulosa
Authors: Brinkworth Craig S. , Pukala Tara L. , Bowie John H. , Tyler Michael J.
Published: July 2004

The host defence peptides from the skin secretions of the Australian Glandular Frog (Litoria subglandulosa) are similar to those of the closely related species Litoria citropa. Both species produce several potent caerulein neuropeptides and antimicrobial- and anticancer-active citropin peptides. The major neuropeptides from Litoria subglandulosa are caerulein 1.1 [pGlu Gln Asp Tyr(SO3) Thr Gly Trp Met Asp Phe–NH2], caerulein 1.2 [pGlu Gln Asp Tyr(SO3) Thr Gly Trp Phe Asp Phe–NH2], and caerulein 2.1 [pGlu Gln Asp Tyr(SO3) Thr Gly Ala His Met Phe–NH2], all of which are smooth muscle active. The major peptide, citropin 1.2 [Gly Leu Phe Asp Ile Ile Lys Lys Val Ala Ser Val Val Gly Gly Leu–NH2], is a wide-spectrum antibiotic and anticancer agent at the micromolar concentration. Citropin 1.2 also inhibits the formation of nitric oxide by the enzyme neuronal nitric oxide synthase (nNOS) at the micromolar concentration. Another peptide, citropin 2.2 [Gly Leu Ile Ser Ile Gly Lys Ala Leu Gly Gly Leu Ile Val Asp Val Leu Lys Pro Lys Ser–OH], also inhibits nNOS.
Pigmentosin A, a New Naphthopyrone from the Lichen Hypotrachyna immaculata
Authors: Elix John A. , Wardlaw Judith H.
Published: July 2004

The new naphthopyrone, pigmentosin A 1, has been isolated from the lichen Hypotrachyna immaculata and its structure elucidated using multidimensional NMR spectroscopic methods, including high-field (600 MHz) gHMBC and gHMQC experiments. This compound is the first lichen metabolite known to contain a bisnaphthopyrone moiety in its structure.
Synthesis of a Novel Nucleoside Based on a Spiroacetal Framework
Authors: Brimble Margaret A. , Robinson James E. , Choi Ka Wai , Woodgate Paul D.
Published: July 2004

The first synthesis of a nucleoside analogue 1 is reported wherein the nucleobase 5-fluorocytosine is attached to a 1,6-dioxaspiro[5.5]undecane spiroacetal ring system. The spiroacetal system acts as a substitute for the sugar unit of natural nucleosides and provides a conformationally restricted framework upon which to append nucleobases in a well defined geometry. Trimethylsilyl triflate promoted Vorbrüggen-type coupling of bis(trimethylsilyl)-5-fluorocytosine 3 with spiroacetal acetate 2 provided spiroacetal nucleoside 1 in which the nucleobase occupied an equatorial position together with the ring opened (Z)-alkene 10. Spiroacetal acetate 2 serves as the spiroacetal donor and was prepared from the readily available starting materials δ-valerolactone and but-3-yn-1-ol 4.
Information constraints and the precision of adaptation: Sex ratio manipulation in wasps
Authors: Shuker David M. , West Stuart A.
Published: July 2004

Sex allocation theory offers excellent opportunities for studying the precision of adaptation. One of the best-supported areas in the field of sex allocation is Hamilton's theory of local mate competition, which predicts female-biased offspring sex ratios when populations are structured such that mating takes place locally before females disperse. As predicted by local mate competition theory, females of numerous species, especially parasitoid wasps, have been shown to lay a less female-biased sex ratio as the number of females simultaneously laying eggs on a patch increases. It has usually been assumed that this sex ratio adjustment comes through individuals adjusting their behavior directly in response to the presence of other females. Here we show that in the parasitoid wasp
Nasonia vitripennis
, this shift in offspring sex ratios is primarily caused by the presence of eggs laid by other females and to a lesser extent by the presence of other females. We confirm that females are behaving as predicted by theory, but the way in which they do so is not as straightforward as is often assumed. Instead, even when there are multiple females on a patch, individuals still use the cues that are more commonly associated with sex ratio adjustment in response to sequential visits to a patch by females. This result provides a possible explanation for the observed variation in
N. vitripennis
sex ratios. More generally, it confirms the need to consider the mechanistic basis of a behavior to understand fully its adaptive value.
Insight into the PrP
C
→ PrP
Sc
conversion from the structures of antibody-bound ovine prion scrapie-susceptibility variants
Authors: Eghiaian Frédéric , Grosclaude Jeanne , Lesceu Stéphanie , Debey Pascale , Doublet Bénédicte , Tréguer Eric , Rezaei Human , Knossow Marcel
Published: July 2004

Prion diseases are associated with the conversion of the α-helix rich prion protein (PrP
C
) into a β-structure-rich insoluble conformer (PrP
Sc
) that is thought to be infectious. The mechanism for the PrP
C
→ PrP
Sc
conversion and its relationship with the pathological effects of prion diseases are poorly understood, partly because of our limited knowledge of the structure of PrP
Sc
. In particular, the way in which mutations in the
PRNP
gene yield variants that confer different susceptibilities to disease needs to be clarified. We report here the 2.5-Å-resolution crystal structures of three scrapie-susceptibility ovine PrP variants complexed with an antibody that binds to PrP
C
and to PrP
Sc
; they identify two important features of the PrP
C
→ PrP
Sc
conversion. First, the epitope of the antibody mainly consists of the last two turns of ovine PrP second α-helix. We show that this is a structural invariant in the PrP
C
→ PrP
Sc
conversion; taken together with biochemical data, this leads to a model of the conformational change in which the two PrP
C
C-terminal α-helices are conserved in PrP
Sc
, whereas secondary structure changes are located in the N-terminal α-helix. Second, comparison of the structures of scrapie-sensitivity variants defines local changes in distant parts of the protein that account for the observed differences of PrP
C
stability, resistant variants being destabilized compared with sensitive ones. Additive contributions of these sensitivity-modulating mutations to resistance suggest a possible causal relationship between scrapie resistance and lowered stability of the PrP protein.
AML1/Runx1 is important for the development of hindbrain cholinergic branchiovisceral motor neurons and selected cranial sensory neurons
Authors: Theriault Francesca M. , Roy Priscillia , Stifani Stefano
Published: July 2004

The mechanisms that regulate the acquisition of distinctive neuronal traits in the developing nervous system are poorly defined. It is shown here that the mammalian
runt
-related gene
Runx1
is expressed in selected populations of postmitotic neurons of the embryonic central and peripheral nervous systems. These include cholinergic branchial and visceral motor neurons in the hindbrain, restricted populations of somatic motor neurons of the median and lateral motor columns in the spinal cord, as well as nociceptive and mechanoreceptor neurons in trigeminal and vestibulocochlear ganglia. In mouse embryos lacking
Runx1
activity, hindbrain branchiovisceral motor neuron precursors of the cholinergic lineage are correctly specified but then fail to progress to a more differentiated state and undergo increased cell death, resulting in a neuronal loss in the mantle layer. In contrast, the development of cholinergic somatic motor neurons is unaffected.
Runx1
inactivation also leads to a loss of selected sensory neurons in trigeminal and vestibulocochlear ganglia. These findings uncover previously unrecognized roles for
Runx1
in the regulation of mammalian neuronal subtype development.
Nanos suppresses somatic cell fate in
Drosophila
germ line
Authors: Hayashi Yoshiki , Hayashi Makoto , Kobayashi Satoru
Published: July 2004

Nanos (Nos) is one of the evolutionarily conserved proteins known to direct germ-line development. In
Drosophila
, maternal Nos protein maintains transcriptional quiescence in the germ-line progenitors or pole cells to repress ectopic expression of somatic genes. Here we show that maternal Nos is required to establish and maintain germ-line identity by preventing apoptosis and somatic cell fate. The pole cells lacking maternal Nos were degraded by apoptosis during mid to late embryogenesis. When apoptosis was suppressed by
Df(3L)H99
, some pole cells lacking Nos adopted somatic cell fates. These pole cells expressed somatic markers ectopically and lost the germ-line marker Vasa. We further found that some Nos-negative pole cells were able to migrate into the gonads, but they failed to develop as functional germ cells during postembryonic stages. We propose a model in which Nos establishes germ-line/soma dichotomy and is also required to maintain germ-line fate.
Distribution of short paired duplications in mammalian genomes
Authors: Thomas Elizabeth E. , Srebro Nathan , Sebat Jonathan , Navin Nicholas , Healy John , Mishra Bud , Wigler Michael
Published: July 2004

Mammalian genomes are densely populated with long duplicated sequences. In this paper, we demonstrate the existence of doublets, short duplications between 25 and 100 bp, distinct from previously described repeats. Each doublet is a pair of exact matches, separated by some distance. The distribution of these intermatch distances is strikingly nonrandom. An unexpectedly high number of doublets have matches either within 100 bp (adjacent) or at distances tightly concentrated ≈1,000 bp apart (nearby). We focus our study on these proximate doublets. First, they tend to have both matches on the same strand. By comparing nearby doublets shared in human and chimpanzee, we can also see that these doublets seem to arise by an insertion event that produces a copy without markedly affecting the surrounding sequence. Most doublets in humans are shared with chimpanzee, but many new pairs arose after the divergence of the species. Doublets found in human but not chimpanzee are most often composed of almost tandem matches, whereas older doublets (found in both species) are more likely to have matches spaced by ≈1 kb, indicating that the nearly tandem doublets may be more dynamic. The spacing of doublets is highly conserved. So far, we have found clearly recognizable doublets in the following genomes:
Homo sapiens
,
Mus musculus
,
Arabidopsis thaliana
, and
Caenorhabditis elegans
, indicating that the mechanism generating these doublets is widespread. A mechanism that generates short local duplications while conserving polarity could have a profound impact on the evolution of regulatory and proteincoding sequences.
Galmic, a nonpeptide galanin receptor agonist, affects behaviors in seizure, pain, and forced-swim tests
Authors: Bartfai Tamas , Lu Xiaoying , Badie-Mahdavi Hedieh , Barr Alasdair M. , Mazarati Andrey , Hua Xiao-Ying , Yaksh Tony , Haberhauer Gebhard , Ceide Susana Conde , Trembleau Laurent , Somogyi Laszlo , Kröck Lenz , Rebek Julius
Published: July 2004

The pharmacological exploitation of the galanin receptors as drug targets for treatment of epilepsy, depression, and pain has been hampered by the lack of workable compounds for medicinal chemists from random screening of large chemical libraries. The present work uses the tripeptidomimetic galnon and displays its presumed pharmacophores on a rigid molecular scaffold. The scaffold is related to marine natural products and presents three functional groups near one another in space, in a manner reminiscent of a protein surface. An active compound, Galmic, was identified from a small synthetic library and testedin vitroandin vivofor its affinity and efficacy at galanin receptors. Galmic has micromolar affinity for GalR1 receptors (Ki= 34.2 μM) and virtually no affinity for GalR2 receptors.In vitro, Galmic, like galanin, suppresses long-term potentiation in the dentate gyrus; it blocks status epilepticus when injected intrahippocampally or administered i.p. Galmic applied i.p. shows antidepressant-like effects in the forced-swim test, and it is a potent inhibitor of flinching behavior in the inflammatory pain model induced by formalin injection. These data further implicate brain and spinal cord galanin receptors as drug targets and provide an example of a systemically active compound based on a scaffold that mimics protein surfaces.
A freestanding proofreading domain is required for protein synthesis quality control in Archaea
Authors: Korencic Dragana , Ahel Ivan , Schelert James , Sacher Meik , Ruan Benfang , Stathopoulos Constantinos , Blum Paul , Ibba Michael , Söll Dieter
Published: July 2004

Threonyl-tRNA synthetase (ThrRS) participates in protein synthesis quality control by selectively editing the misacylated species Ser-tRNA
Thr
. In bacteria and eukaryotes the editing function of ThrRS resides in a highly conserved N-terminal domain distant from the active site. Most archaeal ThrRS proteins are devoid of this editing domain, suggesting evolutionary divergence of quality-control mechanisms. Here we show that archaeal editing of Ser-tRNA
Thr
is catalyzed by a domain unrelated to, and absent from, bacterial and eukaryotic ThrRSs. Despite the lack of sequence homology, the archaeal and bacterial editing domains are both reliant on a pair of essential histidine residues suggestive of a common catalytic mechanism. Whereas the archaeal editing module is most commonly part of full-length ThrRS, several crenarchaeal species contain individual genes encoding the catalytic (ThrRS-cat) and editing domains (ThrRS-ed).
Sulfolobus solfataricus
ThrRS-cat was shown to synthesize both Thr-tRNA
Thr
and Ser-tRNA
Thr
and to lack editing activity against Ser-tRNA
Thr
. In contrast, ThrRS-ed lacks aminoacylation activity but can act as an autonomous protein in trans to hydrolyze specifically Ser-tRNA
Thr
, or it can be fused to ThrRS-cat to provide the same function in cis. Deletion analyses indicate that ThrRS-ed is dispensable for growth of
S. solfataricus
under standard conditions but is required for normal growth in media with elevated serine levels. The growth phenotype of the ThrRS-ed deletion strain suggests that retention of the discontinuous ThrRS quaternary structure relates to specific physiological requirements still evident in certain Archaea.
Lipid- and mechanosensitivities of sodium/hydrogen exchangers analyzed by electrical methods
Authors: Fuster Daniel , Moe Orson W. , Hilgemann Donald W.
Published: July 2004

Sodium/hydrogen exchangers (NHEs) are ubiquitous ion transporters that serve multiple cell functions. We have studied two mammalian isoforms, NHE1 (ubiquitous) and NHE3 (epithelial-specific), by measuring extracellular proton (H+) gradients during whole-cell patch clamp with perfusion of the cell interior. Maximal Na+-dependent H+fluxes (JH+) are equivalent to currents >20 pA for NHE1 in Chinese hamster ovary fibroblasts, >200 pA for NHE1 in guinea pig ventricular myocytes, and 5–10 pA for NHE3 in opossum kidney cells. The fluxes are blocked by an NHE inhibitor, ethylisopropylamiloride, and are absent in NHE-deficient AP-1 cells. NHE1 activity is stable with perfusion of nonhydrolyzable ATP [adenosine 5′-(β,γ-imido)triphosphate], is abolished by ATP depletion (2 deoxy-d-glucose with oligomycin or perfusion of apyrase), can be restored with phosphatidylinositol 4,5-bisphosphate, and is unaffected by actin cytoskeleton disruption (latrunculin or pipette perfusion of gelsolin). NHE3 (but not NHE1) is reversibly activated by phosphatidylinositol 3,4,5-trisphosphate. Both NHE1 and NHE3 activities are disrupted in giant patches during gigaohm seal formation. NHE1 (but not NHE3) is reversibly activated by cell shrinkage, even at neutral cytoplasmic pH without ATP, and inhibited by cell swelling. NHE1 in Chinese hamster ovary fibroblasts (but not NHE3 in opossum kidney cells) is inhibited by agents that thin the membrane (l-α-lysophosphatidylcholine and octyl-β-d-glucopyranoside) and activated by cholesterol enrichment, which thickens membranes. Expressed in AP-1 cells, however, NHE1 is insensitive to these agents but remains sensitive to volume changes. Thus, changes of hydrophobic mismatch can modulate NHE1 but do not underlie its volume sensitivity.
SOX9 is an intestine crypt transcription factor, is regulated by the Wnt pathway, and represses the CDX2 and MUC2 genes
Authors: Blache Philippe , van de Wetering Marc , Duluc Isabelle , Domon Claire , Berta Philippe , Freund Jean-Noël , Clevers Hans , Jay Philippe
Published: July 2004

TCF and SOX proteins belong to the high mobility group box transcription factor family. Whereas TCFs, the transcriptional effectors of the Wnt pathway, have been widely implicated in the development, homeostasis and disease of the intestine epithelium, little is known about the function of the SOX proteins in this tissue. Here, we identified SOX9 in a SOX expression screening in the mouse fetal intestine. We report that the SOX9 protein is expressed in the intestinal epithelium in a pattern characteristic of Wnt targets. We provide in vitro and in vivo evidence that a bipartite β-catenin/TCF4 transcription factor, the effector of the Wnt signaling pathway, is required for SOX9 expression in epithelial cells. Finally, in colon epithelium-derived cells, SOX9 transcriptionally represses the CDX2 and MUC2 genes, normally expressed in the mature villus cells of the intestinal epithelium, and may therefore contribute to the Wnt-dependent maintenance of a progenitor cell phenotype.
Endorepellin causes endothelial cell disassembly of actin cytoskeleton and focal adhesions through α2β1 integrin
Authors: Bix Gregory , Fu Jian , Gonzalez Eva M. , Macro Laura , Barker Amy , Campbell Shelly , Zutter Mary M. , Santoro Samuel A. , Kim Jiyeun K. , Höök Magnus , Reed Charles C. , Iozzo Renato V.
Published: July 2004

Endorepellin, the COOH-terminal domain of the heparan sulfate proteoglycan perlecan, inhibits several aspects of angiogenesis. We provide evidence for a novel biological axis that links a soluble fragment of perlecan protein core to the major cell surface receptor for collagen I, α2β1 integrin, and provide an initial investigation of the intracellular signaling events that lead to endorepellin antiangiogenic activity. The interaction between endorepellin and α2β1 integrin triggers a unique signaling pathway that causes an increase in the second messenger cAMP; activation of two proximal kinases, protein kinase A and focal adhesion kinase; transient activation of p38 mitogen-activated protein kinase and heat shock protein 27, followed by a rapid down-regulation of the latter two proteins; and ultimately disassembly of actin stress fibers and focal adhesions. The end result is a profound block of endothelial cell migration and angiogenesis. Because perlecan is present in both endothelial and smooth muscle cell basement membranes, proteolytic activity during the initial stages of angiogenesis could liberate antiangiogenic fragments from blood vessels' walls, including endorepellin.
Regulation of SNAREs by tomosyn and ROCK
Authors: Sakisaka Toshiaki , Baba Takeshi , Tanaka Shintaro , Izumi Genkichi , Yasumi Masato , Takai Yoshimi
Published: July 2004

Extension of neurites requires the SNARE-dependent fusion of plasmalemmal precursor vesicles with the plasma membrane of growth cones. Here, we show that tomosyn localizes at the palm of growth cones and inhibits the fusion of the vesicles there, thus promoting transport of the vesicles to the plasma membrane of the leading edges of growth cones. Tomosyn localizes because ROCK activated by Rho small G protein phosphorylates syntaxin-1, which increases the affinity of syntaxin-1 for tomosyn and forms a stable complex with tomosyn, resulting in inhibition of the formation of the SNARE complex. In retraction of neurites, tomosyn localizes all over the edges of the neurites and inhibits fusion of the vesicles with the plasma membrane. Thus, tomosyn demarcates the plasma membrane by binding to syntaxin-1 phosphorylated by ROCK, and thereby regulates extension and retraction of neurites.
The Growth-Regulatory Protein HCRP1/hVps37A Is a Subunit of Mammalian ESCRT-I and Mediates Receptor Down-Regulation
Authors: Bache Kristi G. , Slagsvold Thomas , Cabezas Alicia , Rosendal Ken R. , Raiborg Camilla , Stenmark Harald
Published: July 2004

The biogenesis of multivesicular bodies and endosomal sorting of membrane cargo are driven forward by the endosomal sorting complexes required for transport, ESCRT-I, -II, and -III. ESCRT-I is characterized in yeast as a complex consisting of Vps23, Vps28, and Vps37. Whereas mammalian homologues of Vps23 and Vps28 (named Tsg101 and hVps28, respectively) have been identified and characterized, a mammalian counterpart of Vps37 has not yet been identified. Here, we show that a regulator of proliferation, hepatocellular carcinoma related protein 1 (HCRP1), interacts with Tsg101, hVps28, and their upstream regulator Hrs. The ability of HCRP1 (which we assign the alternative name hVps37A) to interact with Tsg101 is conferred by its mod(r) domain and is shared with hVps37B and hVps37C, two other mod(r) domain-containing proteins. HCRP1 cofractionates with Tsg101 and hVps28 by size exclusion chromatography and colocalizes with hVps28 on LAMP1-positive endosomes. Whereas depletion of Tsg101 by siRNA reduces cellular levels of both hVps28 and HCRP1, depletion of HCRP1 has no effect on Tsg101 or hVps28. Nevertheless, HCRP1 depletion strongly retards epidermal growth factor (EGF) receptor degradation. Together, these results indicate that HCRP1 is a subunit of mammalian ESCRT-I and that its function is essential for lysosomal sorting of EGF receptors.
Flexible working: changing the manager's role
Authors: Johnson Janice
Published: July 2004

There are no guarantees of anything in life except death and taxation and so in the meantime organisations must respond to the dynamic changes thrust upon them in order to ensure a means of survival and continuity. The last century saw many changes in work itself and the practice of work. The trend continues into this century where it is almost impossible to visualise how one will be working and in what areas. Yet one needs to have a vision of the future organisation and the future worker in order to begin to manage the necessary structural, technological and psychological changes involved. This paper explores aspects of the changing nature of work and some of the strategies organisations are using to help manage a more demanding (for leisure time and shorter/flexible working hours) worker. It will also examine the changing role of line managers as they attempt to manage the atypical worker and solicit their commitment. Implications and conclusions will highlight the challenges faced by organisations and their workers.