bluuebunny/crossref_metadata_2025 huggingface dataset:
Winter survival and oviposition before and after overwintering of a parasitoid wasp, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae)
Authors: TERAOKA Takeshi , NUMATA Hideharu
Published: June 2004

Winter survival and oviposition before and after overwintering in Ooencyrtus nezarae, an egg parasitoid of phytophagous heteropterans, were examined in Osaka, Japan. Eggs of Riptortus clavatus parasitized by O. nezarae were kept under natural photoperiod and temperature. When honey was supplied, some female adults emerging from early September to late November overwintered. The percentage of overwintering individuals increased as the date of adult emergence advanced. Most female adults supplied with honey and hosts oviposited soon after emergence, then stopped laying eggs. Female adults emerging in mid‐October and early November laid eggs and then overwintered. The induction of diapause in the field seems to vary greatly depending on host availability. Without honey, the survival time of female adults was very short, whether host eggs were supplied or not. After overwintering, most females began to lay eggs in early May if host eggs were supplied, and they produced both male and female progeny. In the study area, a legume field in Osaka, parasitization by O. nezarae was observed from early July to November.
Moths boring into Ficus syconia on Iriomote Island, south‐western Japan
Authors: SUGIURA Shinji , YAMAZAKI Kazuo
Published: June 2004

Herbivory in the syconia of six Ficus (Moraceae) species (F. superba, F. varieagata, F. virgata, F. irisana, F. bengutensis and F. septica) was examined in March 2002 on Iriomote Island, south‐western Japan. Larvae of two lepidopteran species, Pachybotys spissalis (Guenée) (Pyralidae: Pyraustinae) and Stathmopoda sp. (Stathmopodidae) were observed to bore into the Ficus syconia. The attack rate by the moths varied from 0 to 38.5% across Ficus trees. The interiors of the syconia were heavily grazed by the moth larvae. Because figs (syconia) can be regarded as galls and seeds, according to sex and developmental stage, the moth larvae could be considered as gall or seed herbivores, and predators of fig wasps. Moth attack in the Ficus syconia could cause the destruction of fig wasp populations, as fig wasps develop in the syconia.
Non‐specific resistance in brown planthopper resistant indica rice varieties against Plodia interpunctella (Lepidoptera: Phycitidae)
Authors: NAEEMULLAH Muhammad , SHARMA Prem N. , NAKAMURA Chiharu , TAKEDA Makio
Published: June 2004

Mechanisms of host plant resistance against insect pests can be manifold. Resistance screenings generally use single target insect pests, but the resistance thus screened may not always be specific to the target insect species. We conducted a test for non‐specific resistance in indica rice varieties with resistance genes against brown planthopper (BPH), by using the Indian meal moth, Plodia interpunctella. The test system was very simple, and only required the non‐pest moth to be reared on rice flour. We compared the survival rate, developmental period and adult weight of the moth on three rice varieties: ‘Nipponbare’, a BPH‐susceptible japonica variety, and ‘Thai Collection 11’ and ‘Pokkali’, two resistant indica varieties. Our results were straightforward and demonstrate that resistance in the two resistant rice varieties is not BPH specific, because development of the moth was retarded and adult body weight was reduced.
Transformation of garnet epidote amphibolite to eclogite, western Dabie Mountains, China
Authors: Liu J. , Ye K.
Published: June 2004

Omphacite and garnet coronas around amphibole occur in amphibolites in the Hong'an area, western Dabie Mountains, China. These amphibolites consist of an epidote–amphibolite facies assemblage of amphibole, garnet, albite, clinozoisite, paragonite, ilmenite and quartz, which is incompletely overprinted by an eclogite facies assemblage of garnet, omphacite and rutile. Coronas around amphibole can be divided into three types: an omphacite corona; a garnet–omphacite–rutile corona; and, a garnet–omphacite corona with less rutile. Chemographic analysis for local reaction domains in combination with petrographical observations show that reactions Amp + Ab + Pg = Omp +Czo + Qtz + H2O, and Amp + Ab = Omp ± Czo + Qtz + H2O may lead to the development of omphacite coronas. The garnet–omphacite–rutile corona was formed from the reaction Amp + Ab + Czo + Ilm ± Qtz = Omp + Grt + Rt + H2O. In garnet–omphacite coronas, the garnet corona grew during an early stage of epidote amphibolite facies metamorphism, whereas omphacite probably formed by the reactions forming the omphacite corona during the eclogite facies stage. It is estimated that these reactions occurred at 0.8–1.4 GPa and 480–610 °C using the garnet–clinopyroxene thermometer and omphacite barometer in the presence of albite.
High‐Si phengite records the time of greenschist facies overprinting: implications for models suggesting mega‐detachments in the Aegean Sea
Authors: Bröcker M. , Bieling D. , Hacker B. , Gans P.
Published: June 2004

In the lower main unit of the Attic‐Cycladic crystalline belt (Greece), white mica geochronology (Rb–Sr, K–Ar, 40Ar–39Ar) has established the timing of at least two metamorphic events: well‐preserved high‐pressure/low‐temperature (HP/LT) rocks yielded Eocene ages (c. 53–40 Ma) and their greenschist facies counterparts provided Oligocene–Miocene dates (c. 25–18 Ma). Marbles from Tinos Island contain high‐Si phengite with Rb–Sr (phengite–calcite) and 40Ar–39Ar white mica ages between 41 and 24 Ma. All Ar age spectra are disturbed and 40Ar–39Ar total fusion ages generally are 3–6 Ma older than corresponding Rb–Sr ages. Due to the polymetamorphic history, we consider inheritance from the HP stage as the most likely cause for the complex Ar age spectra and the older 40Ar–39Ar dates. This concept also suggests that the Rb–Sr system is more sensitive to modification during overprinting than the Ar isotope system, because resetting of the Sr isotope system can be accomplished more quickly by Sr exchange with other Ca‐rich phases, whereas lack of pervasive deformation and/or restricted availability of synmetamorphic fluids has favoured partial inheritance of the Ar isotope system. On Tinos, the lowermost part of the metamorphic succession has experienced a pervasive greenschist facies overprint. Si‐rich phengite from marbles representing this lithostratigraphic level yielded Rb–Sr ages of c. 24 Ma. If the earlier metamorphic history is not taken into account, such data sets may lead to the erroneous conclusion of Miocene HP metamorphism. This study indicates that this phengite experienced pervasive rejuvenation of the Rb–Sr isotope system during overprinting, without significant changes in Si content, due to bulk‐compositional constraints. This leads to the conclusion that in the absence of critical mineral assemblages the Si value of phengite is not a reliable indicator for metamorphic pressures in impure marbles. Recent studies have reported large displacements (>100 km) for detachment faults in the Aegean Sea. A critical parameter for such models is the age of HP metamorphism as deduced from white mica dating in the basal units of the Cyclades. We question the underlying idea of Miocene HP metamorphism and suggest, instead, that this age constrains the timing of the greenschist facies overprint and that the existence of mega‐detachments in the study area requires further investigation.
Trace element partitioning during high‐P partial melting and melt‐rock interaction; an example from northern Fiordland, New Zealand
Authors: Schröter F. C. , Stevenson J. A. , Daczko N. R. , Clarke G. L. , Pearson N. J. , Klepeis K. A.
Published: June 2004

Pods of granulite facies dioritic gneiss in the Pembroke Valley, Milford Sound, New Zealand, preserve peritectic garnet surrounded by trondhjemitic leucosome and vein networks, that are evidence of high‐P partial melting. Garnet‐bearing trondhjemitic veins extend into host gabbroic gneiss, where they are spatially linked with the recrystallization of comparatively low‐P two‐pyroxene‐hornblende granulite to fine‐grained high‐P garnet granulite assemblages in garnet reaction zones. New data acquired using a Laser Ablation Inductively Coupled Plasma Mass Spectrometer (LA‐ICPMS) for minerals in various textural settings indicate differences in the partitioning of trace elements in the transition of the two rock types to garnet granulite, mostly due to the presence or absence of clinozoisite. Garnet in the garnet reaction zone (gabbroic gneiss) has a distinct trace element pattern, inherited from reactant gabbroic gneiss hornblende. Peritectic garnet in the dioritic gneiss and garnet in trondhjemitic veins from the Pembroke Granulite have trace element patterns inherited from the melt‐producing reaction in the dioritic gneiss. The distinct trace element patterns of garnet link the trondhjemitic veins geochemically to sites of partial melting in the dioritic gneiss.
Silica depleted melting of pelites. Petrogenetic grid and application to the Susqueda Aureole, Spain
Authors: Riesco M. , Stüwe K. , Reche J. , Martinez F. J.
Published: June 2004

Metapelitic rocks in the low pressure contact metamorphic aureole around the Susqueda igneous complex, Spain show a number of features that make them an ideal testing ground for the modelling of silica‐undersaturated melting. Rocks in the aureole experienced localized depletion in silica by the segregation of quartz veins during a pre‐anatectic, regional cordierite‐andalusite grade metamorphic event. These rocks were then intruded by gabbroic to dioritic rocks of the Susqueda igneous complex that formed a migmatitic contact metamorphic aureole in the country rocks. This migmatisation event caused quartz‐saturated hornfels and restite formation in rocks that had experienced no quartz vein segregation in the previous regional metamorphic event, but silica‐undersaturated melting in those rocks that were previously depleted in silica. Silica‐undersaturated melting is investigated using a new petrogenetic P–T projection and equilibrium pseudosections calculated in the KFMASH and NCKFMASH systems, respectively. The grid considers quartz absent equilibria and a range of phases that form typically in silica‐undersaturated bulk compositions, for example corundum. It is shown that the quartz‐rich precursors in the Susqueda contact aureole produced about 10% melt during contact metamorphism. However, most of this melt was extracted leaving behind rocks with restitic bulk compositions and minor leucosome segregation. It is suggested that the melt mixed with the host igneous rocks causing an apparent magmatic zoning from diorite in the centre of the complex to tonalite at the margins. In contrast, the quartz‐poor precursors (from which the quartz veins segregated) melted in the silica‐undersaturated field producing a range of assemblages including peritectic corundum and spinel. Melting of the silica‐undersaturated rocks produced only negligible melt and no subsequent melt loss.
Calculated phase equilibria for low‐ and medium‐pressure metapelites in the KFMASH and KMnFMASH systems
Authors: Wei C. J. , Powell R. , Clarke G. L.
Published: June 2004

Petrogenetic grids in the KFMASH and KMnFMASH model systems calculated with the software thermocalc 3.1 are presented for the P–T range 0.5–12 kbar and 450–900 °C, for assemblages involving garnet, muscovite, chloritoid, biotite, chlorite, staurolite, cordierite, spinel, orthopyroxene, K‐feldspar, Al2SiO5 phases, quartz, water and melt. Based on calculated compatibility diagrams and P–T and T–MMn [Mn/(Mg + Fe + Mn)] pseudosections for different metapelitic bulk compositions, the principal conclusions are that the addition of Mn to the KFMASH system: (i) enhances the stability of garnet, and, to a lesser extent, aluminosilicates; (ii) reduces the stability of staurolite, cordierite and, to a lesser extent, chlorite; and (iii) extends the medium pressure stability of muscovite and the low‐P stability field of K‐feldspar. The influence of Mn on individual mineral stabilities is strongly related to rock composition, in particular, to the relative contents of Al2O3 and K2O. For metapelites of a range of compositions and MMn values, P–T pseudosections in the KFMASH system, in most cases, do not adequately predict the mineral assemblages observed in natural assemblages under medium and low‐pressure conditions. In contrast, the P–T pseudosections in the KMnFMASH system generally provide more satisfactory results, suggesting that MnO is one of the non‐KFMASH components that should not be neglected in documenting the phase equilibria of medium‐ and low‐P metapelites.
The Value of “Final Products” Counts Only Itself
Authors: REISMAN GEORGE
Published: June 2004

Abstract.  The value of final products counts only itself and not the value of so‐called intermediate products. The prevailing, contrary belief entails a twofold violation of the laws of mathematics—namely, the impermissible discarding of essential terms of equations and then the addition of the remainders of equations that are mutually exclusive and therefore not properly subject to addition. It follows that in order to count the values of the so‐called intermediate products, one must go out and count them, because they are not counted in the value of the final product. Despite prevailing belief, counting the value of intermediate products does not represent “double counting.” The implications of these findings for macroeconomic theory are major and include a radically different approach to the respective roles of saving and consumption in spending and income formation, and recognition of the fact that today's concept of gross product is actually a concept of net product.
Smithian National Product and the Wealth of African Nations
Authors: GERDES WILLIAM D.
Published: June 2004

Abstract.  Given the contemporary interest in growth, conventional measures of economic growth (changes in real GDP or real GDP per capita) may be less preferable than a measure that is more plutological by design. The plutological measure presented in this paper is that of Adam Smith (1776). While Smith's work pre‐dated formal national income accounting, there was a macroeconomic accounting scheme implicit in his theorizing on economic growth. This study articulates Adam Smith's concept of national product (referred to as Smithian national product, or SNP). It uses current output data to compute SNP for a set of six African countries, and examines the growth experience of these countries when using SNP as opposed to the more conventional GDP measure.
Searching for a National Policy on the Arts
Authors: Perone Donald Hugh
Published: June 2004

There have always been United States policies on the arts. Some of the nation's founding fathers envisioned federal support for the arts. Congress maintained the Constitution did not empower it to “encourage” the arts, but enacted legislation addressing acknowledged national concerns that also regulated the arts, employed artists, acquired artworks, and created cultural institutions. These uncoordinated de facto arts policies provided models for future action on arts‐related matters.

The federal government's failure to address the arts more directly produced a contentious environment for the nation's artists, leaving them to feel disenfranchised. Advocates’ attempting to gain parity for artists and the arts gave rise to a national movement in the 1930s that continued into the 1960s, and constituted the pregovernmental agenda for the National Foundations on the Arts and the Humanities Act of 1965.
Setting Agendas and Designing Alternatives: Policymaking and the Strategic Role of Meetings1
Authors: Tepper Steven J.
Published: June 2004

This paper investigates the role of strategic forums—such as special commissions, task forces, roundtables, working groups, summits—in the policy process. Reviewing prominent theories about policymaking, the author suggests ways in which strategic forums might fit within these frameworks as an analytically distinct policy lever. The paper examines existing literature on such forums, and identifies characteristics of “meetings that matter”—those gatherings that appear to have achieved some policy traction in a given domain. Finally, the paper investigates a particular field, cultural policy, to evaluate the extent to which meetings are serving policy purposes.

The author concludes that meetings can serve an important role in the policy process by framing public problems and highlighting policy alternatives; creating and sustaining policy communities; fostering policy transfer and knowledge uptake; and developing networks among policy entrepreneurs. Nonetheless, with regard to cultural policy, the author argues that, compared to other policy domains, strategic policy‐focused convenings are not a regular part of the arts and culture landscape and remain underused policy tools.
The Divergent Worlds of New Media: How Policy Shapes Work in the Creative Economy1
Authors: Christopherson Susan
Published: June 2004

“New media” workers have joined the creative economy as digital designers, web page designers, and producers of entertainment products. Like many creative commodity producers, their work lies at the intersection of the technical (in this case code writing) and the expressive (through design). It reflects the tensions inherent in this intersection and the conflicts common to many creative workers who produce commodities but whose work also reflects some element of personal expression or authorship. The ways in which these tensions are resolved is central to the formation of new occupational and professional identities. Cultural economy perspectives offer us insights into the subjective experience of the tensions associated with creative work. They become more powerful, however, when combined with an understanding of the policy context in which new media has evolved. Drawing on both cultural economy and policy analysis approaches, I argue that while new media work emerged in conjunction with new technologies and reflects the tensions between technical applications and design, it also is a product of changes in broader regulatory frameworks that have shaped the work‐world of new media. The “regulatory difference” has produced considerable variation in the occupational identities of new media workers among advanced economies. In some economies, new media work is evolving in a form that is closer to that of the professional, whereas in the United States it is better described as an entrepreneurial activity in which new media workers sell skills and services in a market.

To make this argument I examine findings from the growing body of international work on new media but focus on the particularities of the United States case. What this evidence indicates is that the character of new media occupations is defined as much by the policy context within which it emerges as by the technology it uses.
Maternal and Neonatal Lymphocyte Subpopulations at Delivery and 3 Days Postpartum: Increased Coexpression of CD45 Isoforms
Authors: Juretic Emilia , Gagro Alenka , Vukelic Vesna , Petrovecki Mladen
Published: June 2004

Problem:  Huge physiologic changes during parturition involve immune cells. Alterations in maternal and neonatal lymphocytes postpartum might ascertain the subpopulations that are most affected and may possibly be of importance in the process.

Method of study:  Peripheral blood was taken from 20 healthy women at vaginal delivery and 3 days later, concomitantly with cord and peripheral blood from their newborns. Lymphocyte immunophenotyping was done by three‐color flow‐cytometry.

Results:  Maternal T helper cells were decreased and natural killer (NK) cells were significantly increased during labor. Percentage of CD4+ and percentage and absolute count of CD8+ cells coexpressing CD45RA and CD45RO antigens were higher than 3 days later. In cord blood NK cells were considerably increased and more CD4+ cells expressed CD45RO antigen.

Conclusion:  Coexpression of CD45RA and CD45RO molecules indicates activation of maternal CD4+ and CD8+ lymphocytes. NK cells increase suggests their possible association with parturition processes. Lymphocyte subsets in cord blood correspond to maternal subsets to some extent.
Properties of unitary potentials generated by intramuscular interstitial cells of Cajal in the murine and guinea‐pig gastric fundus
Authors: Beckett E. A. H. , Bayguinov Y. R. , Sanders K. M. , Ward S. M. , Hirst G. D. S.
Published: June 2004

Intracellular recordings were made from isolated bundles of the circular muscle layer of mouse and guinea‐pig gastric fundus. These preparations displayed an ongoing discharge of membrane noise (unitary potentials), similar to that recorded from similar preparations made from the circular layer of the antrum. Bundles of muscle from the fundus of W/WV mice, which lack intramuscular interstitial cells of Cajal (ICCIM) lacked the discharge of membrane noise observed in wild‐type tissues. When the membrane potential was changed by passing depolarizing or hyperpolarizing current pulses, the discharge of membrane noise was little changed. The membrane noise was unaffected by adding chloride channel blockers; however, agents which buffered the internal concentration of calcium ions reduced the discharge of membrane noise. Treatment of tissues with CCCP, which interferes with the uptake of calcium ions by mitochondria, also reduced the membrane noise and caused membrane hyperpolarization. Similar observations were made on bundles of tissue isolated from the circular layer of the guinea pig antrum. Together the observations indicate that membrane noise is generated by a pathway located in ICCIM. The properties of this pathway appear to vary dramatically within a given organ. The lack of voltage sensitivity of the discharge of membrane noise in the fundus provides a possible explanation for the lack of rhythmic electrical activity in this region of the stomach.
Spontaneous synaptic activity is required for the formation of functional GABAergic synapses in the developing rat hippocampus
Authors: Colin‐Le Brun Isabelle , Ferrand Nadine , Caillard Olivier , Tosetti Patrizia , Ben‐Ari Yehezkel , Gaïarsa Jean‐Luc
Published: June 2004

Here we examine the role of the spontaneous synaptic activity generated by the developing rat hippocampus in the formation of functional γ‐aminobutyric acid (GABA) synapses. Intact hippocampal formations (IHFs) were dissected at birth and incubated for 1 day in control or tetrodotoxin (TTX)‐supplemented medium at 25°C. After the incubation, miniature GABAA‐mediated postsynaptic currents (mGABAA‐PSCs) were recorded in whole‐cell voltage‐clamped CA3 pyramidal neurones from IHF‐derived slices. After 1 day in vitro in control medium, the frequency of mGABAA‐PSCs was similar to that recorded in acute slices obtained 1 day after birth, but significantly higher than the frequency recorded from acute slices just after birth. These results suggest that the factors required in vivo for the formation of functional GABAergic synapses are preserved in the IHFs in vitro. The frequency increase was prevented when IHFs were incubated for 1 day with TTX. TTX treatment affected neither the morphology of CA3 pyramidal neurones nor cell viability. The TTX effects were reproduced when IHFs were incubated in the presence of glutamatergic or GABAergic ionotropic receptor antagonists or in high divalent cationic medium. The present results indicate that the spontaneous synaptic activity generated by the developing hippocampus is a key player in the formation of functional GABAergic synapses, possibly via network events requiring both glutamatergic and GABAergic receptors.
The effects of heavy resistance training and detraining on satellite cells in human skeletal muscles
Authors: Kadi Fawzi , Schjerling Peter , Andersen Lars L. , Charifi Nadia , Madsen Jørgen L. , Christensen Lasse R. , Andersen Jesper L.
Published: June 2004

The aim of this study was to investigate the modulation of satellite cell content and myonuclear number following 30 and 90 days of resistance training and 3, 10, 30, 60 and 90 days of detraining. Muscle biopsies were obtained from the vastus lateralis of 15 young men (mean age: 24 years; range: 20–32 years). Satellite cells and myonuclei were studied on muscle cross‐sections stained with a monoclonal antibody against CD56 and counterstained with Mayer's haematoxylin. Cell cycle markers CyclinD1 and p21 mRNA levels were determined by Northern blotting. Satellite cell content increased by 19% (P= 0.02) at 30 days and by 31% (P= 0.0003) at 90 days of training. Compared to pre‐training values, the number of satellite cells remained significantly elevated at 3, 10 and 60 days but not at 90 days of detraining. The two cell cycle markers CyclinD1 and p21 mRNA significantly increased at 30 days of training. At 90 days of training, p21 was still elevated whereas CyclinD1 returned to pre‐training values. In the detraining period, p21 and CyclinD1 levels were similar to the pre‐training values. There were no significant alterations in the number of myonuclei following the training and the detraining periods. The fibre area controlled by each myonucleus gradually increased throughout the training period and returned to pre‐training values during detraining. In conclusion, these results demonstrate the high plasticity of satellite cells in response to training and detraining stimuli and clearly show that moderate changes in the size of skeletal muscle fibres can be achieved without the addition of new myonuclei.
Excitation‐induced Ca2+ influx and muscle damage in the rat: loss of membrane integrity and impaired force recovery
Authors: Ramer Mikkelsen Ulla , Fredsted Anne , Gissel Hanne , Clausen Torben
Published: June 2004

Prolonged or unaccustomed exercise leads to loss of contractility and muscle cell damage. The possible role of an increased uptake of Ca2+ in this was explored by examining how graded fatiguing stimulation, leading to a graded uptake of Ca2+, results in progressive loss of force, impairment of force recovery, and loss of cellular integrity. The latter is indicated by increased [14C]sucrose space and lactic acid dehydrogenase (LDH) release. Isolated rat extensor digitorum longus (EDL) muscles were allowed to contract isometrically using a fatiguing protocol with intermittent stimulation at 40 Hz. Force declined rapidly, reaching 11% of the initial level after 10 min and stayed low for up to 60 min. During the initial phase (2 min) of stimulation 45Ca uptake showed a 10‐fold increase, followed by a 4‐ to 5‐fold increase during the remaining period of stimulation. As the duration of stimulation increased, the muscles subsequently regained gradually less of their initial force. Following 30 or 60 min of stimulation, resting 45Ca uptake, [14C]sucrose space, and LDH release were increased 4‐ to 7‐fold, 1.4‐ to 1.7‐fold and 3‐ to 9‐fold, respectively (P < 0.001). The contents of Ca2+ and Na+ were also increased (P < 0.01), a further indication of loss of cellular integrity. When fatigued at low [Ca2+]o (0.65 mm), force recovery was on average twofold higher than that of muscles fatigued at high [Ca2+]o (2.54 mm). Muscles showing the best force recovery also had a 41% lower total cellular Ca2+ content (P < 0.01). In conclusion, fatiguing stimulation leads to a progressive functional impairment and loss of plasma membrane integrity which seem to be related to an excitation‐induced uptake of Ca2+. Mechanical strain on the muscle fibres does not seem a likely mechanism since very little force was developed beyond 10 min of stimulation.
Regulation of syntaxin1A–munc18 complex for SNARE pairing in HEK293 cells
Authors: Gladycheva Svetlana E. , Ho Chi S. , Lee Yue Ying F. , Stuenkel Edward L.
Published: June 2004

The formation and dissolution of SNARE protein complexes is essential for Ca2+‐triggered fusion of neurotransmitter‐filled vesicles at the presynaptic membrane. Among the pre‐synaptic SNARE proteins, the activation of the Q‐SNARE syntaxin1A is a critical event for SNARE complex formation. Activation requires syntaxin1A to transit from a munc18‐bound non‐interacting state to one competent for SNARE binding. The molecular mechanisms that regulate this transition remain unclear. The propensity of syntaxin1A to promote voltage‐dependent steady‐state inactivation of N‐type Ca2+ channels and accelerate their entry into inactivation was used in a heterologous cell expression system to elucidate regulation of syntaxin1A protein–protein interactions. We report that coexpression of munc18 eliminated the promoting effect of syntaxin1A on inactivation. This effect of munc18 was completely disrupted by coexpression of munc13‐1, but not munc13‐2 or munc13‐3. Also, since expression of munc13‐1 with syntaxin1A resulted in an inactivation phenotype identical to that of munc18 with syntaxin1A, the action of munc13‐1 on the munc18–syntaxin1A complex was functionally unique and did not result from competitive binding interactions. Furthermore, munc13 expressed with syntaxin1A and munc18 promoted redistribution of a cytosolic SNAP25 mutant to the membrane, a result indicative of syntaxin1A–SNAP25 SNARE pairing. These data demonstrate an important role of munc13 to control the protein–protein interactions of syntaxin1A in vivo, and support munc13 as critical to dissociating syntaxin1A–munc18 complexes and making syntaxin1A available for SNARE interactions.
Properties of single voltage‐dependent K+ channels in dendrites of CA1 pyramidal neurones of rat hippocampus
Authors: Chen Xixi , Johnston Daniel
Published: June 2004

Voltage‐dependent K+ channels in the apical dendrites of CA1 pyramidal neurones play important roles in regulating dendritic excitability, synaptic integration, and synaptic plasticity. Using cell‐attached, voltage‐clamp recordings, we found a large variability in the waveforms of macroscopic K+ currents in the dendrites. With single‐channel analysis, however, we were able to identify four types of voltage‐dependent K+ channels and we categorized them as belonging to delayed‐rectifier, M‐, D‐, or A‐type K+ channels previously described from whole‐cell recordings. Delayed‐rectifier‐type K+ channels had a single‐channel conductance of 19 ± 0.5 pS, and made up the majority of the sustained K+ current uniformly distributed along the apical dendrites. The M‐type K+ channels had a single‐channel conductance of 11 ± 0.8 pS, did not inactivate with prolonged membrane depolarization, deactivated with slow kinetics (time constant 100 ± 6 ms at −40 mV), and were inhibited by bath‐applied muscarinic agonist carbachol (10 μm). The D‐type K+ channels had a single‐channel conductance of around 18 pS, and inactivated with a time constant of 98 ± 4 ms at +54 mV. The A‐type K+ channels had a single‐channel conductance of 6 ± 0.6 pS, inactivated with a time constant of 23 ± 2 ms at +54 mV, and contributed to the majority of the transient K+ current previously described. These results suggest both functional and molecular complexity for K+ channels in dendrites of CA1 pyramidal neurones.
A Phenomenological Model for Predicting Fatigue Life in Bovine Trabecular Bone
Authors: Ganguly P. , Moore T. L. A. , Gibson L. J.
Published: June 2004

Cyclic loading of bone during daily activities can lead to fatigue degradation and increased risk of fracture in both the young and elderly population. Damage processes under cyclic loading in trabecular bone result in the reduction of the elastic modulus and accumulation of residual strain. These effects increase with increasing stress levels, leading to a progressive reduction in fatigue life. The present work analyzes the effect of stress and strain variation on the above damage processes in bovine trabecular bone, and develops a phenomenological model relating fatigue life to the imposed stress level. The elastic modulus reduction of the bone specimens was observed to depend on the maximum compressive strain, while the rate of residual strain accumulation was a function of the stress level. A model was developed for the upper and lower bounds of bone elastic modulus reduction with increasing number of cycles, at each stress range. The experimental observations were described well by the model. The model predicted the bounds of the fatigue life with change in fatigue stress. The decrease in the fatigue life with increasing stress was related to corresponding increases in the residual strain accumulation rates at the elevated stress levels. The model shows the validity of fatigue predictions from relatively few cyclic experiments, by combining trends observed in the monotonic and the cyclic tests. The model also presents a relatively simple procedure for predicting the endurance limit for bovine trabecular bone specimens.
Effect of a Lipid Pool on Stress/Strain Distributions in Stenotic Arteries: 3-D Fluid-Structure Interactions (FSI) Models
Authors: Tang Dalin , Yang Chun , Kobayashi Shunichi , Ku David N.
Published: June 2004

Nonlinear 3-D models with fluid-structure interactions (FSI) based on in vitro experiments are introduced and solved by ADINA to perform flow and stress/strain analysis for stenotic arteries with lipid cores. Navier-Stokes equations are used as the governing equations for the fluid. Hyperelastic Mooney-Rivlin models are used for both the arteries and lipid cores. Our results indicate that critical plaque stress/strain conditions are affected considerably by stenosis severity, eccentricity, lipid pool size, shape and position, plaque cap thickness, axial stretch, pressure, and fluid-structure interactions, and may be used for possible plaque rupture predictions.
Geometric Determinants to Cement Line Debonding and Osteonal Lamellae Failure in Osteon Pushout Tests
Authors: Dong X. Neil , Guo X. Edward
Published: June 2004

Cement lines are the boundaries between secondary osteons and the surrounding interstitial bone matrix in cortical bone. The interfacial properties of cement lines have been determined by osteon pushout tests. However, distinctively different material properties were obtained when osteon pushout tests were performed under different test geometries. In the present study, an axisymmetric two-dimensional finite element model was used to simulate an osteon pushout test using the test geometry of actual experiments. The results indicated that shear failure within the osteonal lamellae would occur when the osteon pushout test was performed under the condition of a thick specimen and large supporting hole. On the other hand, cement line debonding occurred when the osteon pushout test was performed using a thin specimen and small supporting hole. The finite element results were consistent with previous experiments of osteon pushout tests under different test geometries. Furthermore, the finite-element results suggest that a smoothly curved punch would most likely cause debonding at the cement line instead of osteonal lamellae.
Does Sex Age You?
Authors: Proulx Stephen R.
Published: June 2004

The evolution of aging and longevity has typically been considered to be a resolution of the conflicting demands on an organism to grow, reproduce, and survive. When social or environmental factors change the opportunities for reproduction in a way that affects differently aged individuals, there will be an evolutionary response in the schedule of senescence. This means that social dynamics can have an important effect on aging. A recent study by Berec and Boukal has shown that the dynamics of mating and divorce can also affect observed life spans through their effect on population dynamics. If females cannot find and maintain mating pairs for long enough to replace themselves, the population will become extinct. This puts a lower limit on the levels of longevity that will be observed in nature.
Illegal Formation
Authors: Leslie Mitch
Published: June 2004

The biological clock that counts down a woman's childbearing years might be sitting on the ends of her chromosomes. A new study suggests that dwindling telomeres disrupt chromosomal liaisons necessary for making sperm and eggs. The results could help explain why infertility rates rise as women grow older.
Lethal Leak
Authors: Davenport R. John
Published: June 2004

Perforating mitochondria might accelerate aging, according to a new study. A protein called p66shc that speeds the demise of mice breaches these organelles, a key event in cell death. The work reveals new information about p66shc's workings, but researchers caution that they don't yet know whether the protein influences life span through this route.
From Womb the Bell Tolls
Authors: Davenport R. John
Published: June 2004

Years of lethargy and too many cheeseburgers can give a retiree diabetes, but adversity in the womb might also cultivate the condition. According to new work, aged rats display some signs of diabetes if their mothers were stressed during pregnancy. The research adds to evidence that fetal experiences can influence adult health, although scientists don't know how much the prenatal environment contributes to disease.
Many Roads to Ruin
Authors: Leslie Mitch
Published: June 2004

As researchers begin to understand the molecular faults that weaken tissues and organs over time, they are learning that some types of trouble undermine specific tissues and others affect multiple tissues. In certain tissues, for example, mature cells kill themselves in droves. In muscles, stem cells that fix injuries stop dividing. In the bones and arteries, stem cells specialize inappropriately. Putting stem cells back to work might allow scientists to repair damage. By prodding them in the bone marrow, for example, researchers might coax the damaged heart to repair itself.
Methods for Genetic Dissection of Complex Traits
Authors: Mackay Trudy F. C.
Published: June 2004

In this Perspective, the author responds to a recent SAGE KE
Perspective
. An alternative view of the benefits of quantitative trait loci mapping as a way to understand the molecular mechanisms of life-span determination is presented.
Vital Connections
Authors: Pletcher Scott D.
Published: June 2004

Scientists are currently exploring the structure and behavior of complex biological systems, which consist of networks of interacting entities. A recent paper in
Proceedings of the Royal Society of London Series B Biological Sciences
describes the distinctive characteristics of aging-related proteins in the yeast protein-protein interaction network. In this Perspective, I discuss the implications of these findings for longevity research.
Anxious Aging
Authors: Beckman Mary
Published: June 2004

People complain that getting old is stressful, and now scientists might have proven them right. Many of the same genes change their output in old flies and oxidatively stressed young flies, suggesting that the aged insects are beleaguered on the molecular level. In addition, an aging-related increase in the activity of immune-system genes supports the notion that a general inflammatory response heightens as animals age. The results also reveal bursts of protein production that might eventually allow scientists to predict an individual fly's life span.
Shining a Light on Long Life
Authors: Leslie Mitch
Published: June 2004

For fruit flies, longevity is only a mutation away. A new study sheds light on one of the insects' most famous life-extending gene glitches. The work identifies molecules that activate a protein that adjusts fly aging, and the results might help clarify whether the same protein shapes human survival.
Early Life Predictors of Old-Age Life Expectancy
Authors: Rikke Brad A.
Published: June 2004

The laboratory of Richard Miller and numerous heroic collaborators are in the process of testing a variety of life span predictors on more than 1000 mice. In their most recent publication, Harper

et al.

show that early-adulthood measures of T cell subsets, body weight, and thyroxine can be effectively combined to provide a highly significant predictor of life expectancy. Each measure appears to be an index of largely separate parameters that affect the course of aging. This article summarizes the results, discusses implications, mentions caveats, and suggests future studies.
Merging Routes
Authors: Davenport R. John
Published: June 2004

Cells, like people, lose their vitality, and researchers are eager to track down the mechanisms that prompt normal cell life to screech to a halt. New research helps enumerate the proteins that make cells stagnate when chromosome ends fray--and reveals that one protein halts cells by other means. The findings bolster the idea that signals other than eroding telomeres can shut down cells.
Symphony of Errors
Authors: Landhuis Esther
Published: June 2004

An orchestra's sound quality suffers whether each member of the cello section flubs a particular pitch or scattered violinists play random notes offkey. Similarly, cells can atrophy when they amass many identical mitochondrial DNA defects or, according to new work, multiple haphazard flaws. The findings support the much-debated theory that accumulation of assorted blunders in the mitochondrial genome underlies aging. Because this type of slip-up commonly occurs in mammals, the results could hold significance for humans.
Declining Immunity with Age in the Wild
Authors: Holmes Donna , Austad Steven
Published: June 2004

Despite their higher metabolic rates and lifetime energy expenditures, birds generally outlive similar-sized mammals even in the wild, often reaching maturity and aging considerably more slowly. Wild populations of many bird species have been monitored for years using banding-and-recapture methods, allowing field ornithologists to document age-related declines in survival and reproductive success. Although elderly birds rarely reach advanced stages of senescence in nature, many show other signs of physiological deterioration. In this Perspective, we review recent reports of aging-related changes in the immune response of two small European songbirds, the barn swallow and the collared flycatcher. Researchers in both studies challenged birds' humoral immune response by administering antigen to free-ranging adults during the breeding season. Older barn swallows--particularly breeding females--showed lower antibody responses (both primary and secondary) to vaccination with Newcastle disease virus, an avian pathogen. In flycatchers, older females raised lower antibody titers than younger breeders did in response to an injection of sheep red blood cells, a nonpathogenic antigen, and produced offspring with lower average body masses. Although the relevance of such measures of "immunosenescence" to actual fitness, reproductive success, and mortality is still unclear, studies of wild vertebrate populations may ultimately provide an important link between laboratory research and our understanding of the natural history and evolution of basic mechanisms of aging.
Peer Pressure
Authors: Davenport R. John
Published: June 2004

On her own, a Girl Scout might pick up trash on her street, but a whole troop can redecorate a nursing home. An antioxidant protein in yeast also changes its behavior when it congregates with others, according to a new study. It stops quenching free radicals and starts helping proteins fold. Although researchers don't yet know whether its mammalian counterpart behaves similarly, that protein might apply this newfound power to help fight cancer and aging.
Neurodegeneration in Normal Brain Aging and Disease
Authors: Thal Dietmar Rudolf , Del Tredici Kelly , Braak Heiko
Published: June 2004

Normal "healthy" aging is defined as aging without disease. Many aged people do not exhibit symptoms of disease and lead normal lives, but nonetheless display pathological changes that are characteristic of Alzheimer's disease (AD), Parkinson's disease (PD), dementia with Lewy bodies (DLB), and/or cerebrovascular disease (CVD). These changes are restricted to distinct brain regions and might represent preclinical stages of these disorders. This Perspective discusses arguments in favor of and against the hypothesis that pathological changes related to AD, PD, DLB, and CVD in the brains of nondemented elderly people represent early stages of these diseases rather than healthy aging. We conclude that early pathological disease-related changes do indeed constitute the beginning of AD, PD, DLB, and CVD rather than normal concomitants of aging, even in the absence of any clinical symptoms. Aging is, therefore, a major risk factor for these diseases but does not necessarily lead to age-related diseases.
Too Much of a Good Thing
Authors: Davenport R. John
Published: June 2004

If security forces overreact, they can hamper normal activities. Similarly, an overly zealous disaster response disrupts sugar processing in mice, new work reveals. The study suggests that oxidants play a crucial role in molecular communication.
Racing Against Time
Authors: Chen Ingfei
Published: June 2004

As a scientist-physician at Tufts University School of Medicine in Boston, Leslie Gordon is pushing to find a cure for Hutchinson-Gilford progeria syndrome (HGPS)--a rare and deadly disease that afflicts her own son, Sam. HGPS mimics certain aspects of aging, and patients survive an average of 13 years, usually dying from heart disease. In 1999, Gordon and her husband, pediatric emergency physician Scott Berns, set up the Progeria Research Foundation. The organization has created essential resources for scientists investigating HGPS, including a cell and tissue bank and a clinical database that tracks the medical history of patients worldwide. Gordon also spearheaded the formation of a research consortium that in 2003 announced the discovery of the gene that goes awry in HGPS.
Layer-Specific Somatosensory Cortical Activation During Active Tactile Discrimination
Authors: Krupa David J. , Wiest Michael C. , Shuler Marshall G. , Laubach Mark , Nicolelis Miguel A. L.
Published: June 2004

Ensemble neuronal activity was recorded in each layer of the whisker area of the primary somatosensory cortex (SI) while rats performed a whisker-dependent tactile discrimination task. Comparison of this activity with SI activity evoked by similar passive whisker stimulation revealed fundamental differences in tactile signal processing during active and passive stimulation. Moreover, significant layer-specific functional differences in SI activity were observed during active discrimination. These differences could not be explained solely by variations in ascending thalamocortical input to SI. Instead, these results suggest that top-down influences during active discrimination may alter the overall functional nature of SI as well as layer-specific mechanisms of tactile processing.
Earthquakes Beneath the Himalayas and Tibet: Evidence for Strong Lithospheric Mantle
Authors: Chen Wang-Ping , Yang Zhaohui
Published: June 2004

Eleven intracontinental earthquakes, with magnitudes ranging from 4.9 to 6, occurred in the mantle beneath the western Himalayan syntaxis, the western Kunlun Mountains, and southern Tibet (near Xigaze) between 1963 and 1999. High-resolution seismic waveforms show that some focal depths exceeded 100 kilometers, indicating that these earthquakes occurred in the mantle portion of the lithosphere, even though the crust has been thickened there. The occurrence of earthquakes in the mantle beneath continental regions where the subduction of oceanic lithosphere ceased tens of millions years ago indicates that the mantle lithosphere is sufficiently strong to accumulate elastic strain.
Robust Temporal Coding in the Trigeminal System
Authors: Jones Lauren M. , Depireux Didier A. , Simons Daniel J. , Keller Asaf
Published: June 2004

The ability of rats to use their whiskers for fine tactile discrimination rivals that of humans using their fingertips. Rats perform discriminations rapidly and accurately while palpating the environment with their whiskers. This suggests that whisker deflections produce a robust and reliable neural code. Whisker primary afferents respond with highly reproducible temporal spike patterns to transient stimuli. Here we show that, with the use of a linear kernel, any of these reproducible response trains recorded from an individual neuron can reliably predict complex whisker deflections. These predictions are significantly improved by integrating responses from neurons with opposite angular preferences.