bluuebunny/crossref_metadata_2025 huggingface dataset:
Pasture seed dynamics in a dry monsoonal climate. I Germination and seedbed environment of Stylosanthes humilis and Digitaria ciliaris
Authors: McKEON G. M. , ROSE C. W. , KALMA J. D. , TORSSELL B. W. R.
Published: July 2006

Field germination behaviour and seedbed environment of the annual legume Townsville stylo (Stylosanthes humilis) and the vigorous annual grass weed (Digitaria ciliaris) were studied at Katherine, Northern Territory. Previous studies of the population dynamics of these pastures had indicated the importance of the germination‐establishment phase in maintaining S. humilis as a pasture component.

Analysis of seed samples at the time of sward establishment showed that near complete germination of viable seed (in the case of D. ciliaris) and of soft seed (in the case of S. humilis) occurred in the early storm period before the onset of the wet season. Swards of both species generally resulted from a single, major germination wave often after an isolated rainfall.

The seedbed environment at the time of major germination waves was studied in detail for 2 years and environmental models were used with historical climate records to calculate probability distributions of temperature and moisture over 16 years. The main determinants of the seedbed environment were storms (most often occurring in the period from late afternoon to midnight) and high solar radiation levels (70% > 20 MJ m‐2 day‐1 in the days after rainfall. Surface soil generally dries to ‐1.5 MPa by noon. Minimum night surface temperatures showed little variation (∼25°C) and were followed by high surface temperatures the following day (> 35°C). The use of a simple water balance model showed a high chance (80% of events) of the top 40 mm drying to – 1.5 MPa at the end of the second day following rainfall.

Despite the low variation of annual rainfall at Katherine (cv of 20%) these self regenerating annual species have a high risk of seedling death. Germination and seedling establishment take place at a time of rapid fluctuations in surface moisture and seedbed temperature. The analysis of seedbed conditions indicated that intensive sampling of the seed population would be required in the early storm period to explain differential survival of the species and that laboratory work should concentrate on factors controlling speed of germination over short periods of available moisture (12–20 h).
Pasture seed dynamics in a dry monsoonal climate, II The effect of water availability, light and temperature on germination speed and seedling survival of Stylosanthes humilis and Digitaria ciliaris
Authors: McKEON G. M.
Published: July 2006

Environmental factors affecting speed of germination and survival of naturally occurring seed of the legume Stylosanthes humilis and the grass Digitaria ciliaris were studied. Previous studies on the seedbed environment had shown that germination speed, defined as the proportion of seeds capable of germinating in the first 12 h period, was likely to be the most relevant laboratory measurement. Ten studies were conducted to compare species performance and to devise a standard technique for the measurement of germination speed under laboratory conditions.

For S. humilis, the level and duration of submergence in water in the germination test had a large effect on germination speed (from 0–70% in 12 h). The absence of light delayed germination (7% in 12 h compared to 52% under light), but did not prevent complete germination over 7 days. Optimum temperature was 25°C with a decrease to 0% at 30°C. A standard technique was developed for measuring potential germination speed which gave reproducible results allowing differences in seed lots to be described.

D. ciliaris seeds sampled just prior to field germination in the early storm period were less sensitive to environmental control. Temperature optimum for germination decreased from 40 to 30°C with the duration of the germination test. Seeds sampled at the time of seed dispersal (early dry season) had a high fraction (80%) requiring light for germination but this requirement had been lost by the early storm period.

Investigations on the role of leaching (water movement) showed that long periods of water movement (12–18 h) increased the speed of germination of both species and in the case of S. humilis overcame environmental blocks to rapid germination (absence of light or 30°C temperature).

Root elongation rates in S. humilis were not greatly affected by temperature over the range of seedbed temperatures when moisture is available (25–40°C) in the field. However, D. ciliaris was delayed in development at 25°C, the most likely overnight surface soil temperature. D. ciliaris was more susceptible to death by desiccation once germination had occurred compared to S. humilis. In both species seedling death due to desiccation increased with stage of development.

The better relative performance of S. humilis in the germination‐establishment phase of the life cycle, which had been observed in a previous study, could be explained by a qualitative comparison of the species' attributes. This suggested that D. ciliaris was more likely to germinate at rainfall events following which there was a greater chance of seedling death
Comparison of insects and vertebrates as removers of seed and fruit in a Western Australian forest
Authors: ABBOTT IAN , VAN HEURCK PAUL
Published: July 2006

Removal from the forest floor of seed or fruit of the six commonest species of trees in upland areas of the northern jarrah forest of Western Australia was studied experimentally. The smallest seeds (Eucalyptus marginata, Allocasuarina fraseriana) were taken by insects (presumably ants). Heavier seeds or fruits (E. calophylla, Banksia grandis, Persoonia longifolia, P. elliptica) were taken more often by vertebrates (presumably srrmll mammals). Seeds of E. calophylla and B. grandis were most preferred by vertebrates, possibly because they have the highest relative concentrations of nitrogen and phosphorus.
Seed release in Banksia: the role of wet‐dry cycles
Authors: COWLING RICHARD M. , LAMONT BYRON B.
Published: July 2006

Seed release in two serotinous and two nonserotinous Banksia species from southwestern Australia increased many fold when burnt cones were subjected to wet‐dry cycles compared with those remaining air‐dry. The response was temperature‐dependent, increasing markedly in treated cones of B. leptophylla as temperature was lowered from 30 to 15°C. This episodic wetting requirement at cool temperatures for prolific seed release implies that, following summer fruit opening, dispersal is delayed until the onset of late autumn/early winter rains when conditions are suitable for germination (optimum at ∼15°C) and recruitment. Seed loss from post‐dispersal predation and exposure to high summer soil temperatures also would be minimized.
Dispersal of the winged fruits of Nuytsia floribunda (Loranthaceae)
Authors: LAMONT BYRON
Published: July 2006

Fruits of the tree Nuytsia floribunda are dispersed by wind during autumn to mid‐winter when conditions are suitable for germination. While the greatest density of fallen fruits occurs beneath the canopy, most are dispersed well beyond the tree in the direction of the prevailing west‐southwesterly winds, with a minor peak corresponding to the easterlies. A multiple regression equation, which accounted for 77.5% of variance, was derived to account for the greatest dispersal distance per tree. This comprises, in decreasing order of importance, tree height, log (fruit load), and leeward and windward plant cover in the vertical plane. Extrapolation indicated a maximum distance of about 50 m can be expected, which is insufficient to account for the location of at least 6.5% of adult trees at the study site. This supports other evidence that suckering may play a major role in the spread of this species. Additional experiments confirmed the importance of wind velocity in the distance reached by fruits and the absence of biotic dispersal agents.
Food and foraging behaviour of the lizard, Ctenotus taeniolatus
Authors: TAYLOR JANET A.
Published: July 2006

A sample of 261 Ctenotus taeniolatus revealed that this species of skink is principally insectivorous, the most common foods being lepidopteran and coleopteran larvae, orthopterans and formicids. The occurrence of these foods in the diet followed seasonal patterns. The prey of adults and juveniles did not differ qualitatively, although adults were capable of eating a greater diversity of prey sizes than juveniles. Lizards used both sit‐and‐wait and active foraging strategies, with adults and juveniles exhibiting these behaviours in different ratios.
Invertebrate communities on Western Australian eucalypts: A comparison of branch clipping and chemical knockdown procedures
Authors: MAJER J. D. , RECHER H. F.
Published: July 2006

Chemical knockdown and branch clipping procedures were used in wandoo (Eucalyptus wandoo) woodland and jarrah (E. marginata)/marri (E. calophylla) open‐forest to sample arboreal invertebrate faunas on three species of Western Australian eucalypts. Jarrah was sampled in both habitats and had significantly lower invertebrate populations and a less diverse fauna than either wandoo or marri. The two procedures provided similar results with respect to the relative abundance of invertebrates on each plant species but the knockdowns sampled a more diverse fauna, including species sheltering in or on bark. Chemical knockdowns underestimated the abundance of sessile invertebrates, such as psyllids. Branch clipping sampled insufficient numbers of large, mobile, or cryptic invertebrates to estimate abundances, but provided a more accurate estimate of the abundance of sessile, leaf‐dwelling organisms. Neither procedure provides a complete sample of arboreal invertebrates, but they are complementary. When used in conjunction with each other a more complete estimate of arboreal invertebrate abundance and diversity is obtained. Both procedures can be used concurrently with only a small increase in field time.
Pollination ecology of Christmas Bells (Blandfordia nobilis): Patterns of standing crop of nectar
Authors: ZIMMERMAN MICHAEL , PYKE GRAHAM H.
Published: July 2006

Standing crop of nectar (both volume and sugar concentrations) was measured from flowers in a population of Blandfordia nobilis. Nectar in this honeyeater‐pollinated species was extremely viscous during one flowering season and averaged approximately 95% sugar, while it averaged only 25% sugar two seasons later. Nectar volume was significantly and negatively correlated with sugar concentration on nine often sampling dates. There was no significant relationship between either nectar volume or sugar concentration and a number of measures of plant size (inflorescence height, numbers of open flowers, buds, spent flowers and total flowers). Similarly, no consistent relationship was found between measures of flower size and reward level. There were significant positive correlations between the reward (both volume and sugar concentration) offered by blossoms on the same plant. The nectar volume of flowers from nearest neighbouring inflorescences were significantly and positively correlated with one another on three of six occasions while the sugar concentrations of those blossoms were significantly correlated on just two of six sampling dates. There was no significant difference in reward (both volume and sugar concentration) between open flowers and those bagged to exclude pollinators. There was significant heterogeneity in the nectar volumes offered by plants to pollinators during a single flowering season.
Dynamics of resprouting in the lignotuberous shrub Banksia oblongifolia
Authors: ZAMMIT CHARLES
Published: July 2006

The resprouting response of different sized Banksia oblongifolia lignotubers (genets) was followed in two field experiments. In the first, the density and speed of resprouting, and the growth in length of the leading shoot from each lignotuber in response to fire and to the time elapsed since the last fire was monitored for 18 months after fire and clipping treatments. In the second, sizes of bud banks were estimated by repeatedly clipping new shoots from individual lignotubers.

Density of resprouting (shoots dm−2 lignotuber) decreased with increasing lignotuber size, and the length of the leading shoot increased. The direct effect of fire was to reduce shoot density by about 75%. The speed of resprouting (time taken by a cohort of shoots to reach 50% of their peak density) was similar after fire and clipping, but leading shoots grew significantly longer after fire. The elapsed time since lignotubers were last burnt did not influence their density of resprouting, but it did influence the speed of resprouting. Shoots from clipped lignotubers that had burnt 3 years earlier took about 90 days to each 50% of their peak density while shoots on lignotubers last burnt 5 and 17 years earlier took about 40 days. Death of shoots was unrelated to crowding in any stand. More lignotubers from the oldest unburnt stand were grazed by herbivores.

The number of buds converted into shoots after successive clippings was surprisingly small; for most lignotubers this reserve was less than three times the size of their standing crop of shoots. In general, the smaller lignotubers carried a higher proportion of dormant buds in relation to their standing crop of shoots. About 30% of buds remained dormant after the first clipping and about 10% after the second and third clippings. Evidence suggests that buds are replaced within 6 months of fire. No lignotubers survived four clippings over 15 months.
MCMC for Integer‐Valued ARMA processes
Authors: Neal Peter , Subba Rao T.
Published: July 2006

Abstract.  The classical statistical inference for integer‐valued time‐series has primarily been restricted to the integer‐valued autoregressive (INAR) process. Markov chain Monte Carlo (MCMC) methods have been shown to be a useful tool in many branches of statistics and is particularly well suited to integer‐valued time‐series where statistical inference is greatly assisted by data augmentation. Thus in this article, we outline an efficient MCMC algorithm for a wide class of integer‐valued autoregressive moving‐average (INARMA) processes. Furthermore, we consider noise corrupted integer‐valued processes and also models with change points. Finally, in order to assess the MCMC algorithms inferential and predictive capabilities we use a range of simulated and real data sets.
The transcriptional repressor REST is a critical regulator of the neurosecretory phenotype
Authors: Bruce Alexander W. , Krejčí Alena , Ooi Lezanne , Deuchars James , Wood Ian C. , Doležal Vladimír , Buckley Noel J.
Published: July 2006

Release of distinct cellular cargoes in response to specific stimuli is a process fundamental to all higher eukaryotes and controlled by the regulated secretory pathway (RSP). However, the mechanism by which genes involved in the RSP are selectively expressed, leading to the establishment and appropriate functioning of regulated secretion remaining largely unknown. Using the rat pheochromocytoma cell line PC12, we provide evidence that, by controlling expression of many genes involved in the RSP, the transcriptional repressor REST can regulate this pathway and hence the neurosecretory phenotype. Introduction of REST transgenes into PC12 cells leads to the repression of many genes, the products of which are involved in regulated secretion. Moreover, chromatin immunoprecipitation assays show that many of the repressed genes recruit the recombinant REST protein to RE1 sites within their promoters and abrogation of REST function leads to reactivation of these transcripts. In addition to the observed transcriptional effects, PC12 cells expressing REST have fewer secretory granules and a reduction in the ability to store and release noradrenaline. Furthermore, an important trigger for synaptic release, influx of calcium through voltage‐operated calcium channels, is compromised. This is the first demonstration of a transcription factor that directly controls expression of many major components of the RSP and provides further insight into the function of REST.
Glutamate‐induced protease‐mediated loss of plasma membrane Ca2+ pump activity in rat hippocampal neurons
Authors: Pottorf William J. , Johanns Tanner M. , Derrington Stephen M. , Strehler Emanuel E. , Enyedi Agnes , Thayer Stanley A.
Published: July 2006

Ca2+ dysregulation is a hallmark of excitotoxicity, a process that underlies multiple neurodegenerative disorders. The plasma membrane Ca2+ ATPase (PMCA) plays a major role in clearing Ca2+ from the neuronal cytoplasm. Here, we show that the rate of PMCA‐mediated Ca2+ efflux from rat hippocampal neurons decreased following treatment with an excitotoxic concentration of glutamate. PMCA‐mediated Ca2+ extrusion following a brief train of action potentials exhibited an exponential decay with a mean time constant (τ) of 8.8 ± 0.2 s. Four hours following the start of a 30 min treatment with 200 µm glutamate, a second population of cells emerged with slowed recovery kinetics (τ = 16.5 ± 0.3 s). Confocal imaging of cells expressing an enhanced green fluorescent protein (EGFP)‐PMCA4b fusion protein revealed that glutamate treatment internalized EGFP and that cells with reduced plasma membrane fluorescence had impaired Ca2+ clearance. Treatment with inhibitors of the Ca2+‐activated protease calpain protected PMCA function and prevented EGFP‐PMCA internalization. PMCA internalization was triggered by activation of NMDA receptors and was less pronounced for a non‐toxic concentration of glutamate relative to one that produces excitotoxicity. PMCA isoform 2 also internalized following exposure to glutamate, although the Na+/K+ ATPase did not. These data suggest that glutamate exposure initiated protease‐mediated internalization of PMCAs with a corresponding loss of function that may contribute to the Ca2+ dysregulation that accompanies excitotoxicity.
Coexistence of TACS and Trigeminal Neuralgia: Pathophysiological Conjectures
Authors: Leone Massimo , Mea Eliana , Genco Sergio , Bussone Gennaro
Published: July 2006

Background.—Trigeminal autonomic cephalgias (TACs) and trigeminal neuralgia are short‐lasting unilateral primary headaches whose study is providing insights into craniofacial pain mechanisms. We report on 2 patients in whom trigeminal neuralgia coexists with the TACs paroxysmal hemicrania and SUNCT.

Conclusion.—Coexistence of trigeminal neuralgia with various TAC forms suggests a pathophysiological relationship between these short‐lasting unilateral headaches.
Daily Variation in Adolescents' Sleep, Activities, and Psychological Well‐Being
Authors: Fuligni Andrew J. , Hardway Christina
Published: July 2006

The daily diary method was used to examine the daily dynamics of adolescent sleep time, activities, and psychological well‐being among an ethnically diverse sample of over 750 adolescents approximately 14–15 years of age. Studying and stressful demands during the day were modestly but consistently associated with less sleep that evening. Receiving less sleep at night, in turn, was modestly but consistently related to higher levels of anxiety, depressive feelings, and fatigue during the following day. In addition, the daily variability in adolescents' sleep time was notable and just as important for the youths' average levels of daily psychological well‐being as was the average amount of time spent sleeping each night. A small number of ethnic and gender differences emerged in the dynamics of adolescent sleep, activities, and well‐being. Discussion focuses on the importance of examining variability in adolescents' sleep behaviors in order to better understand the implications of sleep for adolescent well‐being and development.
Self Processes in Adolescent Depression: The Role of Self‐Worth Contingencies
Authors: Burwell Rebecca A. , Shirk Stephen R.
Published: July 2006

Although biased self‐evaluation is a component of several disorders, most measures focus on the content of self‐concepts or level of self‐worth rather than the process by which self‐worth is maintained. This longitudinal study examines the distinctive role of self‐worth contingencies—the extent to which adolescents link self‐worth to external feedback and success in four domains (social, academic, activities, and appearance) in the development of depressive symptoms among a sample of 110 adolescents (age mean=13.62, SD=.52; 58.2% girls). Contingencies predicted change in depressive symptoms over time, but depressive symptoms did not predict change in contingencies over time. This pattern did not hold for the association between self‐worth and depression. Findings provide support for contingencies as a predictor, rather than a symptom, of depressive symptoms among adolescents. Evaluation of contingencies as a diathesis revealed an interaction effect for the social, but not academic domain. The findings have implications self‐worth contingencies as an important cognitive vulnerability to depressive symptoms during adolescence.
Examining School Connectedness as a Mediator of School Climate Effects
Authors: Loukas Alexandra , Suzuki Rie , Horton Karissa D.
Published: July 2006

Researchers have suggested that good‐quality school climates foster a sense of connection to the school and in this way contribute to fewer emotional and behavioral problems. However, few studies have directly assessed the role of school connectedness as a mediator of school climate effects. Using path analysis, this brief report examined whether four aspects of student perceived school climate (cohesion, friction, competition among students, and overall satisfaction with classes) were indirectly associated with subsequent early adolescent conduct problems and depressive symptoms through school connectedness. Participants were four hundred and eighty‐nine 10‐ to 14‐year old middle school students involved in two waves of a study. The results showed that school connectedness mediated the relations between perceived cohesion, perceived friction, and overall satisfaction with classes and subsequent student conduct problems 1 year later. School connectedness was not, however, predictive of subsequent depressive symptoms and thus did not mediate the school climate effects on early adolescent emotional problems.
Simian foamy virus infection by whole‐blood transfer in rhesus macaques: potential for transfusion transmission in humans
Authors: Khan Arifa S. , Kumar Dhanya
Published: July 2006

BACKGROUND: Cross‐species infection of humans with simian foamy virus (SFV) has been reported in European and North American nonhuman primate (NHP) handlers, primarily due to wound injuries involving infected animals in research centers and zoos. Additionally, African hunters have been found to be infected with SFV by exposure to body fluids, blood, or tissues of infected NHPs in the wild. The persistence of infectious virus in peripheral blood mononuclear cells (PBMNC) and the recent identification of some infected blood donors has raised safety concerns regarding potential virus transmission by blood transfusion.

STUDY DESIGN AND METHODS: SFV infection by blood transfusion was evaluated by whole‐blood transfer from two naturally‐infected rhesus macaques (designated as D1 and D2) to retrovirus‐free monkeys. Blood from D1 was transfused to two recipient monkeys R1 and R2 and from D2 to monkeys R3 and R4. Virus transmission was evaluated by immunoassays, polymerase chain reaction assays, and coculture of PBMNC for SFV isolation.

RESULTS: SFV infection was seen in R1 and R2 based on development of virus‐specific antibodies, identification of SFV sequences in monkey PBMNC, and isolation of infectious virus from PBMNC. Furthermore, both R1 and R2 remained SFV‐positive at about 1 year after transfusion, which was the last time tested. No evidence of SFV infection was seen in R3 and R4.

CONCLUSION: SFV transmission in macaques occurred by transfusion of blood from one of two infected donor animals. These results indicate the potential of SFV transfusion transmission in humans, which may depend on virus‐specific or donor‐related factors.
Template‐assisted rational design of peptide inhibitors of furin using the lysine fragment of the mung bean trypsin inhibitor
Authors: Tao Hu , Zhang Zhen , Shi Jiahao , Shao Xiao‐xia , Cui Dafu , Chi Cheng‐wu
Published: July 2006

Highly active, small‐molecule furin inhibitors are attractive drug candidates to fend off bacterial exotoxins and viral infection. Based on the 22‐residue, active Lys fragment of the mung bean trypsin inhibitor, a series of furin inhibitors were designed and synthesized, and their inhibitory activity towards furin and kexin was evaluated using enzyme kinetic analysis. The most potent inhibitor, containing 16 amino acid residues with a Ki value of 2.45 × 10−9 m for furin and of 5.60 × 10−7 m for kexin, was designed with three incremental approaches. First, two nonessential Cys residues in the Lys fragment were deleted via a Cys‐to‐Ser mutation to minimize peptide misfolding. Second, residues in the reactive site of the inhibitor were replaced by the consensus substrate recognition sequence of furin, namely, Arg at P1, Lys at P2, Arg at P4 and Arg at P6. In addition, the P7 residue Asp was substituted with Ala to avoid possible electrostatic interference with furin inhibition. Finally, the extra N‐terminal and C‐terminal residues beyond the doubly conjugated disulfide loops were further truncated. However, all resultant synthetic peptides were found to be temporary inhibitors of furin and kexin during a prolonged incubation, with the scissile peptide bond between P1 and P1′ being cleaved to different extents by the enzymes. To enhance proteolytic resistance, the P1′ residue Ser was mutated to d‐Ser or N‐methyl‐Ser. The N‐methyl‐Ser mutant gave rise to a Ki value of 4.70 × 10−8 m for furin, and retained over 80% inhibitory activity even after a 3 h incubation with the enzyme. By contrast, the d‐Ser mutant was resistant to cleavage, although its inhibitory activity against furin drastically decreased. Our findings identify a useful template for the design of potent, specific and stable peptide inhibitors of furin, shedding light on the molecular determinants that dictate the inhibition of furin and kexin.
When positive selection of neurotoxin genes is missing
Authors: Moran Yehu , Gurevitz Michael
Published: July 2006

Rapid evolution driven by positive Darwinian selection appears in toxins of vipers, scorpions, and marine snails. Although the vast phylogenetic distances between these animals suggest that this phenomenon is common, the recent release of the genome ofNematostella vectensis(Starlet anemone) as a collection of contigs portrays another extreme. Besides potassium channel toxin domains, which resemble potassium channel blockers, embedded in various genes, only one gene family encoding for sodium channel neurotoxins has been found, and the putative mature product of 10 family members is identical. Whereas the existence of a single toxin encoded by multiple genes may be explained by the unique ecology ofN. vectensis, the complete absence of substitutions including synonymous ones is surprising and suggests either that these genes have been duplicated recently, or that their total conservation was advantageous. A retro‐element identified downstream to one of the genes offers a possible mechanism of enhanced toxin gene duplication. This assumption still awaits further verification as soon as the various contigs are assigned within larger genomic fragments.
Microstructural and Mechanical Properties Changes of a NiCoCrAlY Bond Coat with Heat Exposure Time in Air Plasma‐Sprayed Y2O3–ZrO2 TBC Systems
Authors: Hasegawa Makoto , Kagawa Yutaka
Published: July 2006

Changes in the microstructure and Young's modulus of NiCoCrAlY bond coat (BC) layer in a Y2O3 partially stabilized ZrO2 thermal barrier coating system exposed at 1423 K up to 100 h have been studied. Under the as‐sprayed condition, the BC layer consists of a fine mixture of β and γ′ phases. After heat exposure, the phases change in two different zones; in the zones adjacent to the TBC and substrate layers, a γ phase is present, and in the mid‐zone between the two interfaces, a mixture of β and γ phases is present. With an increase in exposure time, the BC microstructure transforms with time into a single γ phase. Young's modulus of the BC increases with increasing heat exposure time. In the as‐sprayed state, the global effective Young's modulus of the BC is originally 178 GPa and with an increase in exposure time changes to 182, 186, and 192 GPa after 10, 50, and 100 h of heat exposure time, respectively. This observation is explained by the change in the microstructure from the γ′ to the γ phase and the increase of existing γ phase, as the Young's modulus of the γ phase is higher than the β and γ′ phases.
Glass–Ceramic Composites with Strontium Hexaferrite Ultrafine Particles in the SrO–Fe2O3–B2O3–SiO2 System
Authors: Zaitsev Dmitry D. , Gravchikova Ekaterina A. , Kazin Pavel E. , Tretyakov Yury D. , Jansen Martin
Published: July 2006

Glass samples with nominal compositions SrFe12O19+(12−n)SrB2O4+nSrSiO3, n=3, 6, 9 were prepared by rapid quenching of the melt. Processes of glass devitrification were studied. The samples were annealed at temperatures of 600–900°C, and the resulting glass–ceramics was characterized by XRD, SEM, EDX, and magnetic measurements. SrFe12O19 crystallizes above 700°C and forms nano‐ and submicron platelet particles with the aspect ratio depending on the thermal treatment conditions. The glass–ceramic samples annealed at 900°C show coercive force values in the range of 422–455 kA/m.
Behavioral Response of Satellite‐collared Elephants to the Tsunami in Southern Sri Lanka1
Authors: Wikramanayake Eric , Fernando Prithiviraj , Leimgruber Peter
Published: July 2006

After the Asian tsunami the media was inundated with reports of aberrant behavior among animals attributed to a “sixth sense” that allowed them to respond to the catastrophe ahead of the impact. We present behavior data from two satellite‐collared Asian elephants that ranged close to the tsunami impact area in Sri Lanka. These data indicate that neither elephant behaved in a manner consistent with a “sixth sense” that allowed an early detection of the approaching tsunami.
Variation in Seedling Density and Seed Predation Indicators for the Emergent Tree Dipteryx panamensis in Continuous and Fragmented Rain Forest1
Authors: Hanson Thor , Brunsfeld Steven , Finegan Bryan
Published: July 2006

Seedling density and the condition of stony endocarps of the tree Dipteryx panamensis were assessed in protected continuous forest and two forest fragments exposed to hunting and selective logging. Seedling density was higher in forest fragments than in continuous forest, while more whole endocarps and fewer chewed and half endocarps were found in fragments, indicating lower seed predation at fragment sites. These findings appear to contradict two earlier D. panamensis studies and we discuss methodological differences that could account for our disparate results. Hunting and fragmentation effects on mammal populations are suggested as a cause for the altered recruitment pattern in fragments.
Protecting or punishing children: physical punishment, human rights and English law reform
Authors: Keating Heather
Published: July 2006

This paper assesses the current state of English criminal law in relation to the use of physical force by parents as a means of disciplining their children. It does so in the light of the Children Act 2004, the European Convention for the Protection of Human Rights and Fundamental Freedoms 1950, Art 3, pressure from bodies such as the United Nations Committee on the Rights of the Child and the law in other parts of Europe. It acknowledges that parents should have a large degree of autonomy in relation to parenting. However, the defence of ‘discipline’ or ‘reasonable chastisement’ is outdated, vague and potentially dangerous to children. It is argued that the response of the British Government to criticism of our law has been far from satisfactory. The reform which was incorporated into the Children Act 2004 as a result of pressure upon the government aims to avoid criminalising ‘ordinary families’ for minor smacks. However, the statement of principle is so diluted that parents might understandably be confused and enforcement may be difficult. Moreover, the pressure for reform has continued unabated. The paper concludes that what is needed is an outright ban, combined with an educational campaign, which can lead the way in changing the cultural tradition of physical punishment.
Reduced ability to release adenosine by diabetic rat cardiac fibroblasts due to altered expression of nucleoside transporters
Authors: Podgorska Marzena , Kocbuch Katarzyna , Grden Marzena , Szutowicz Andrzej , Pawelczyk Tadeusz
Published: July 2006

Adenosine produced by cardiac cells is known to attenuate the proliferation of cardiac fibroblasts (CFs), inhibit collagen synthesis, and protect the myocardium against ischaemic and reperfusion injury. Diabetic patients' hearts exhibit ventricular hypertrophy and demonstrate reduced tolerance to hypoxia or ischaemia. In this study, we characterize the effects of glucose and insulin on processes that determine the release of adenosine from CFs. We showed that during ATP depletion, rat CFs cultured in the absence of insulin release significantly less adenosine compared to cells grown in the presence of insulin. Moreover, under both conditions the quantity of released adenosine depends on glucose concentration. We demonstrate that this is due to altered expression of nucleoside transporters. High glucose (25 mm) induced 85% decrease in nucleoside transporter ENT1 mRNA levels. Decrease of the insulin level below 10−11m resulted in over 3‐fold increase in the nucleoside transporter CNT2 mRNA content. Measurements of adenosine transport in CFs cultured in the presence of 5 mm glucose and 10 nm insulin showed that the bidirectional equilibrative adenosine transport accounted for 70% of the overall adenosine uptake. However, cells grown in the presence of high glucose (25 mm) demonstrated 65% decrease of the bidirectional equilibrative adenosine transport. Experiments on CFs cultured in the absence of insulin showed that the unidirectional Na+‐dependent adenosine uptake rose in these cells more than 4‐fold. These results indicate that the development of diabetes may result in an increased uptake of interstitial adenosine by CFs, and reduction of the ability of these cells to release adenosine during ATP deprivation.
Position sense at the human forearm in the horizontal plane during loading and vibration of elbow muscles
Authors: Ansems G. E. , Allen T. J. , Proske U.
Published: July 2006

When blindfolded subjects match the position of their forearms in the vertical plane they rely on signals coming from the periphery as well as from the central motor command. The command signal provides a positional cue from the accompanying effort sensation required to hold the arm against gravity. Here we have asked, does a centrally generated effort signal contribute to position sense in the horizontal plane, where gravity cannot play a role? Blindfolded subjects were required to match forearm position for the unloaded arm and when flexors or extensors were bearing 10%, 25% or 40% of maximum loads. Before each match the reference arm was conditioned by contracting elbow muscles while the arm was held flexed or extended. For the unloaded arm conditioning led to a consistent pattern of errors which was attributed to signals from flexor and extensor muscle spindles. When elbow muscles were loaded the errors from conditioning converged, presumably because the spindles had become coactivated through the fusimotor system during the load‐bearing contraction. However, this convergence was seen only when subjects supported a static load. When they moved the load differences in errors from conditioning persisted. Muscle vibration during load bearing or moving a load did not alter the distribution of errors. It is concluded that for position sense of an unloaded arm in the horizontal plane the brain relies on signals from muscle spindles. When the arm is loaded, an additional signal of central origin contributes, but only if the load is moved.
A conserved ring of charge in mammalian Na+ channels: a molecular regulator of the outer pore conformation during slow inactivation
Authors: Xiong Wei , Farukhi Yousaf Z. , Tian Yanli , DiSilvestre Deborah , Li Ronald A. , Tomaselli Gordon F.
Published: July 2006

The molecular mechanisms underlying slow inactivation in sodium channels are elusive. Our results suggest that EEDD, a highly conserved ring of charge in the external vestibule of mammalian voltage‐gated sodium channels, undermines slow inactivation. By employing site‐directed mutagenesis, we found that charge alterations in this asymmetric yet strong local electrostatic field of the EEDD ring significantly altered the kinetics of slow inactivation gating. Using a non‐linear Poisson–Boltzmann equation, quantitative computations of the electrostatic field in a sodium channel structural model suggested a significant electrostatic repulsion between residues E403 and E758 at close proximity. Interestingly, when this electrostatic interaction was eliminated by the double mutation E403C + E758C, the kinetics of recovery from slow inactivation of the double‐mutant channel was retarded by 2500% compared to control. These data suggest that the EEDD ring, located within the asymmetric electric field, is a molecular motif that critically modulates slow inactivation in sodium channels.
A spinal vasopressinergic mechanism mediates hyperosmolality‐induced sympathoexcitation
Authors: Antunes V. R. , Yao S. T. , Pickering A. E. , Murphy D. , Paton J. F. R.
Published: July 2006

An elevation in plasma osmolality elicits a complex neurohumoral response, including an activation of the sympathetic nervous system and an increase in arterial pressure. Using a combination of in vivo and in situ rat preparations, we sought to investigate whether hypothalamic vasopressinergic spinally projecting neurones are activated during increases in plasma osmolality to elicit sympathoexcitation. Hypertonic saline (HS, i.v. bolus), which produced a physiological increase in plasma osmolality to 299 ± 1 mosmol (kg water)−1, elicited an immediate increase in mean arterial pressure (MAP) (from 101 ± 1 to 121 ± 3 mmHg) in vivo. Pre‐treatment with prazosin reversed the HS‐induced pressor response to a hypotensive response (from 121 ± 3 to 68 ± 2 mmHg), indicating significant activation of the sympathetic nervous system. In an in situ arterially perfused decorticate rat preparation, hyperosmotic perfusate consisted of either 135 mm NaCl, or a non‐NaCl osmolyte, mannitol (0.5%); both increased lumbar sympathetic nerve activity (LSNA) by 32 ± 5% (NaCl) and 21 ± 1% (mannitol), which was attenuated after precollicular transection (7 ± 3% and 1 ± 1%, respectively). Remaining experiments used the NaCl hyperosmotic stimulus. In separate preparations the hyperosmotic‐induced sympathoexcitation (21 ± 2%) was also significantly attenuated after transection of the circumventricular organs (2 ± 1%). Either isoguvacine (a GABAA receptor agonist) or kynurenic acid (a non‐selective ionotropic glutamate receptor antagonist) microinjected bilaterally into the paraventricular nucleus (PVN) attenuated the increase in LSNA induced by the hyperosmotic stimulus (control: 25 ± 2%; after isoguvacine: 7 ± 2%; after kynurenic: 8 ± 3%). Intrathecal injection of a V1a receptor antagonist also reduced the increase in LSNA elicited by the hyperosmotic stimulus (control: 29 ± 6%; after blocker: 4 ± 1%). These results suggest that a physiological hyperosmotic stimulus produces sympathetically mediated hypertension in conscious rats. These data are substantiated by the in situ decorticate preparation in which sympathoexcitation was also evoked by comparable hyperosmotic stimulation. Our findings demonstrate the importance of vasopressin acting on spinal V1a receptors for mediating sympathoexcitatory response to acute salt loading.
Evidence that stimulation of ghrelin receptors in the spinal cord initiates propulsive activity in the colon of the rat
Authors: Shimizu Yasutake , Chang Ed C. , Shafton Anthony D. , Ferens Dorota M. , Sanger Gareth J. , Witherington Jason , Furness John B.
Published: July 2006

Previous studies have failed to reveal an effect of the gastrointestinal peptide hormone ghrelin on colonic motility. In the present work, ghrelin was applied into the lumbo‐sacral spinal cord in the region of defecation control centres, and a synthetic ghrelin receptor agonist, CP464709, which crosses the blood–brain barrier, was applied intravenously or into the lumbo‐sacral cord. Both ghrelin and CP464709 elicited propulsive contractions and emptying of the colon in anaesthetized rats. In conscious rats, subcutaneous CP464709 caused fecal expulsion. The sites of action and nerve pathways involved in the stimulation of the colon by ghrelin receptor activation were investigated in anaesthetized rats. Intrathecal application of CP464709 at L6–S1, but not application at ponto‐medullary levels or to the thoracic spinal cord, elicited propulsive contractions. The stimulation evoked by intravenous CP464709 was prevented if the pelvic nerve outflows were severed, but not if the spinal cord was cut rostral to the defecation centre at L6–S3. The response was also blocked by hexamethonium. When ghrelin, applied intrathecally, was used to desensitize its receptors, the effect of intravenous CP464709 was blocked. CP464709 did not affect small intestine motility or the amplitudes of visceromotor reflexes caused by colorectal distension. It is concluded that activation of ghrelin receptors in the lumbo‐sacral spinal cord triggers co‐ordinated propulsive contractions that empty the colo‐rectum. The pathways through which these responses are generated pass out of the spinal cord via the pelvic nerves and cause propulsive contractions through activation of enteric neurons.
Electrical events underlying organized myogenic contractions of the guinea pig stomach
Authors: Hirst G. David S. , Edwards Frank R.
Published: July 2006

The stomach generates a characteristic pattern of coordinated activity whereby rings of contraction regularly start in the corpus and migrate slowly down the stomach to the duodenum. This behaviour persists after isolating the stomach and after blocking nervous activity; hence the response is myogenic, resulting from organized contractions of smooth muscle cells lying in the stomach wall. Each ring of contraction is triggered by a long lasting wave of depolarization, termed a slow wave. Slow waves are now known to be generated by sets of interstitial cells of Cajal (ICC), which intermingle with gastric smooth muscle cells. This article describes some studies which identify the roles played by ICC in the on‐going generation of coordinated gastric movements. Intramuscular ICC in the corpus generate slow waves and these provide the dominant pacemaker frequency in the stomach. Corporal slow waves, in turn, activate a network of myenteric ICC, which starts in the antrum and slowly conducts waves of depolarization down the stomach. As these waves pass over bundles of circularly orientated muscle cells, they activate a set of intramuscular ICC which lie in the circular muscle layer: these generate slow waves that rapidly spread radially, so triggering each ring of contraction.
Genome Sequence Diversity and Clues to the Evolution of Variola (Smallpox) Virus
Authors: Esposito Joseph J. , Sammons Scott A. , Frace A. Michael , Osborne John D. , Olsen-Rasmussen Melissa , Zhang Ming , Govil Dhwani , Damon Inger K. , Kline Richard , Laker Miriam , Li Yu , Smith Geoffrey L. , Meyer Hermann , LeDuc James W. , Wohlhueter Robert M.
Published: July 2006

Comparative genomics of 45 epidemiologically varied variola virus isolates from the past 30 years of the smallpox era indicate low sequence diversity, suggesting that there is probably little difference in the isolates' functional gene content. Phylogenetic clustering inferred three clades coincident with their geographical origin and case-fatality rate; the latter implicated putative proteins that mediate viral virulence differences. Analysis of the viral linear DNA genome suggests that its evolution involved direct descent and DNA end-region recombination events. Knowing the sequences will help understand the viral proteome and improve diagnostic test precision, therapeutics, and systems for their assessment.
Volcanism in Response to Plate Flexure
Authors: Hirano Naoto , Takahashi Eiichi , Yamamoto Junji , Abe Natsue , Ingle Stephanie P. , Kaneoka Ichiro , Hirata Takafumi , Kimura Jun-Ichi , Ishii Teruaki , Ogawa Yujiro , Machida Shiki , Suyehiro Kiyoshi
Published: July 2006

Volcanism on Earth is known to occur in three tectonic settings: divergent plate boundaries (such as mid-ocean ridges), convergent plate boundaries (such as island arcs), and hot spots. We report volcanism on the 135 million-year-old Pacific Plate not belonging to any of these categories. Small alkalic volcanoes form from small percent melts and originate in the asthenosphere, as implied by their trace element geochemistry and noble gas isotopic compositions. We propose that these small volcanoes erupt along lithospheric fractures in response to plate flexure during subduction. Minor extents of asthenospheric melting and the volcanoes' tectonic alignment and age progression in the direction opposite to that of plate motion provide evidence for the presence of a small percent melt in the asthenosphere.
Impact of privacy legislation on the number and characteristics of people who are recruited for research: a randomised controlled trial
Authors: Trevena L , Irwig L , Barratt A
Published: July 2006

Background:Privacy laws have recently created restrictions on how researchers can approach study participants.

Method:In a randomised trial of 152 patients, 50–74 years old, in a family practice, 60 were randomly selected to opt-out and 92 to opt-in methods. Patients were sent an introductory letter by their doctor in two phases, opt-out before and opt-in after introduction of the new Privacy Legislation in December 2001. Opt-out patients were contacted by researchers. Opt-in patients were contacted if patients responded by email, free telephone number or a reply-paid card.

Results:Opt-in recruited fewer patients (47%; 43/92) after invitation compared with opt-out (67%; 40/60); (−20%; [−4% to −36%]). No proportional difference in recruitment was found between opt-in and opt-out groups varied by age, sex or socioeconomic status. The opt-in group had significantly more people in active decision-making roles (+30%; [10% to 50%]; p = 0.003). Non-significant trends were observed towards opt-in being less likely to include people with lower education (−11.8%; [−30% to 6.4%]; p = 0.13) and people who were not screened (−19.1%; [−40.1% to 1.9%]; p = 0.08). Opt-in was more likely to recruit people with a family history of colorectal cancer (+12.7%; [−2.8%, 28.2%]; p = 0.12).

Conclusions:The number of participants required to be approached was markedly increased in opt-in recruitment. Existing participants (eg, screening attendees) with a vested interest such as increased risk, and those preferring an active role in health decision making and with less education were likely to be recruited in opt-in. Research costs and generalisability are affected by implementing privacy legislation.