bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of sand creep on a flat sand bed using a high‐speed digital camera
Authors: WANG YUAN , WANG DAWEI , WANG LI , ZHANG YANG 
Published: March 2009

AbstractIn this study, a novel method for measuring sand creep along a flat bed was developed. Specifically, a high‐speed digital camera was employed to record the sand creep movement. With an unsigned image subtraction, a new image queue could be formed from the original experimental images. The particle tracking was then calculated, after which the velocity and trajectory of the creep of sand grains was obtained. In addition, the creep fluxes of the different sand samples could also be calculated based on the velocities of the creep grains.
An experimental study into the geometry of supply‐limited dunes
Authors: TUIJNDER ARJAN P. , RIBBERINK JAN S. , HULSCHER SUZANNE J. M. H. 
Published: March 2009

AbstractThe relationship between dune geometry and the volume of mobile sediment was studied in flume experiments. In these flume experiments, the volume of mobile sediment on top of an immobile coarse sediment layer was increased stepwise and the bedform characteristics were observed. A strong relationship was found between the volume that is mobile – and therefore available for bedform formation – and the dune dimensions and regularity. If the sediment supply is limited, dunes are smaller and more regular. Series of experiments with a decreasing supply limitation were conducted for different flow velocities and water depths. The relationship between the dune dimensions and the available volume is different for each series. The observed relationships between dune dimensions and layer thickness collapse to one relationship for height and one for length if scaling parameters are introduced. Current models for bedform dimensions under alluvial conditions can be extended to partial transport conditions using this relationship.
Cold hardiness of southern‐adapted blueberry (Vaccinium × hybrid) genotypes and the potential for their use in northern‐adapted blueberry breeding
Authors: Ehlenfeldt M. K. , Rowland L. J. , Ogden E. L. , Vinyard B. T. 
Published: March 2009

AbstractTwelve southern‐adapted blueberry genotypes, both southern highbush (Vaccinium corymbosum L. introgressed with 2x V. darrowi Camp) and rabbiteye (V. ashei Reade), were evaluated for bud development using a morphological scale and for mid‐winter cold hardiness using a shoot freezing assay. The winter of 2006–2007 was particularly warm producing higher bud development scores for several of the genotypes and an apparent decrease of cold hardiness. Significant differences in LT50 values (treatments causing 50% bud mortality) were observed among the genotypes in both years, with a significant clone × year interaction. The greatest range in LT50 values occurred in 2007, when values ranged from −11.9°C for ‘Millennia’ to −25.5°C for ‘Reveille’, two southern highbush cultivars. Results suggest that germplasm selected in North Carolina might typically have sufficient cold hardiness to be used without concern as parental material in the development of blueberry germplasm with northern adaptation. Other more southern germplasm was generally less hardy and, if utilized as parental material, the resulting progeny would require greater scrutiny with regard to cold hardiness.
A review on transgenic approaches to accelerate breeding of woody plants
Authors: Flachowsky H. , Hanke M.‐V. , Peil A. , Strauss S. H. , Fladung M. 
Published: March 2009

AbstractThe long juvenile period of trees delays the breeding of new varieties. Flowering begins within 5–10 years in most cultivated forest trees under intensive management, but can take up to 40 years in some species and environmental conditions. To accelerate the breeding process several agrotechnical and biotechnical methods have been developed. Knowledge about genes controlling flower initiation in model plants like Arabidopsis thaliana, and identification of homologous genes in trees, have led to new possibilities for early‐flower induction. Overexpression of MADS‐box and other floral regulatory genes resulted in early flowering in some tree species and/or varieties. However, these methods have not yet been shown to enable the production of fertile, viable or normal gametes and progeny; developmental research towards these ends is therefore of high priority. A breeding scheme has been developed to use early flowering trees for the introduction of genes from wild species that would allow several backcrosses to occur in only a few years, and to produce at the end a non‐transgenic improved variety. Research to develop practical early flowering methods could lead to several new methods for breeding and biotechnology.
EFFECTS OF EXPERIMENTALLY INDUCED DIABETES MELLITUS ON PHARMACOLOGICALLY AND ELECTRICALLY ELICITED MYOMETRIAL CONTRACTILITY
Authors: Spiegl Gábor , Zupkó István , Minorics Renáta , Csík Gábor , Csonka Dénes , Falkay George 
Published: March 2009

SUMMARYDiabetes is one of the most frequent complications of gestation, affecting approximately 7% of pregnancies. However, little is known about its effects on electrically and pharmacologically stimulated myometrial contractility. The aim of the present study was to investigate the consequences of streptozotocin (STZ)‐induced diabetes on: (i) electrical field stimulation (EFS)‐evoked contraction of isolated uterine rings as a function of gestational age; and (ii) the uterotonic and tocolytic actions of α‐ and β‐adrenoceptor stimulation, respectively. The effects of oxytocin in late pregnancy were also investigated.During pregnancy, EFS‐evoked contractions of isolated uterine rings from intact rats declined, whereas isolated uterine rings from diabetic rats exhibited continuously low sensitivity to EFS.In non‐pregnant rats, diabetes resulted in increased noradrenaline‐mediated contractility and a decreased relaxation response to terbutaline. At the mRNA level, diabetes enhanced the expression of α1B‐adrenoceptors in non‐pregnant rats from 14.65 to 18.39 µg/mL (P < 0.05), whereas the expression of α1D‐adrenoceptors decreased (from 42.87 to 35.67 µg/mL;P < 0.05). During pregnancy, the responses to these sympathomimetics did not differ between diabetic and intact rats.In late pregnancy (on Days 15 and 21), oxytocin caused greater maximum contractility of uterine rings from diabetic rats without affecting the EC50. In addition, on Day 15 of pregnancy, the expression of oxytocin receptors in the myometrium of diabetic rats was higher than that in intact rats.The results of the present study indicate that experimental diabetes facilitates gestation‐induced denervation and increases myometrial sensitivity to oxytocin in late pregnancy. If similar mechanisms operate in humans, this could contribute to a tendency to premature uterine contractions in diabetes‐complicated pregnancies.
FLUOXETINE PROTECTS AGAINST MONOCROTALINE‐INDUCED PULMONARY ARTERIAL HYPERTENSION: POTENTIAL ROLES OF INDUCTION OF APOPTOSIS AND UPREGULATION OF Kv1.5 CHANNELS IN RATS
Authors: Zhai Feng‐Guo , Zhang Xin‐Hua , Wang Huai‐Liang 
Published: March 2009

SUMMARY

Suppressing apoptosis and downregulating K+ channels in pulmonary artery smooth muscle cells (PASMC) have been implicated in the development of pulmonary vascular medial hypertrophy and pulmonary arterial hypertension (PAH). Previous studies have shown that selective serotonin re‐uptake inhibitors (SSRIs) protected against PAH. The aim of the present study was to investigate the involvement of Kv1.5 channels and apoptosis in the protective effect of the SSRI fluoxetine against PAH.
Monocrotaline (MCT) was used to establish PAH in Wistar rats. Fluoxetine (2 and 10 mg/kg per day) was administered by gavage once a day for 3 weeks. Three weeks after the induction of PAH by MCT, pulmonary haemodynamic measurements and pulmonary artery morphological assessments were undertaken, along with detection of apoptosis and Kv1.5.
Fluoxetine (2 and 10 mg/kg per day) decreased pulmonary artery pressure, reduced the right ventricular index and inhibited the increase in medial wall thickness of pulmonary arteries in established PAH. Fluoxetine (10 mg/kg per day) reduced the expression of Bcl‐2 and Bcl‐xL protein, increased the expression of cleaved caspase 3 protein and enhanced the expression of Kv1.5 protein and mRNA in pulmonary arteries. Furthermore, fluoxetine (10 mg/kg per day) significantly suppressed proliferation and enhanced apoptosis of PASMC in MCT‐induced PAH.
In conclusion, fluoxetine protects against MCT‐induced PAH by suppressing PASMC proliferation, inducing PASMC apoptosis and upregulating Kv1.5 channels.
Pharmacological changes in cellular Ca2+homeostasis parallel initiation of atrial arrhythmogenesis in murine langendorff‐perfused hearts
Authors: Zhang Yanmin , Schwiening Christof , Killeen Matthew J , Zhang Yanhui , Ma Aiqun , Lei Ming , Grace Andrew A , Huang Christopher L‐H 
Published: March 2009

SummaryIntracellular Ca2+overload has been associated with established atrial arrhythmogenesis. The present experiments went on to correlate acute initiation of atrial arrhythmogenesis in Langendorff‐perfused mouse hearts with changes in Ca2+homeostasis in isolated atrial myocytes following pharmacological procedures that modified the storage or release of sarcoplasmic reticular (SR) Ca2+or inhibited entry of extracellular Ca2+.Caffeine (1 mmol/L) elicited diastolic Ca2+waves in regularly stimulated atrial myocytes immediately following addition. This was followed by a decline in the amplitude of the evoked transients and the disappearance of such diastolic events, suggesting partial SR Ca2+depletion.Cyclopiazonic acid (CPA; 0.15 µmol/L) produced more gradual reductions in evoked Ca2+transients and abolished diastolic Ca2+events produced by the further addition of caffeine.Nifedipine (0.5 µmol/L) produced immediate reductions in evoked Ca2+transients. Further addition of caffeine produced an immediate increase followed by a decline in the amplitude of the evoked Ca2+transients, without eliciting diastolic Ca2+events.These findings correlated with changes in spontaneous and provoked atrial arrhythmogenecity in mouse isolated Langendorf‐perfused hearts. Thus, caffeine was pro‐arrhythmogenic immediately following but not > 5 min after application and both CPA and nifedipine pretreatment inhibited such arrhythmogenesis.Together, these findings relate acute atrial arrhythmogenesis in intact hearts to diastolic Ca2+events in atrial myocytes that, in turn, depend upon a finite SR Ca2+store and diastolic Ca2+release following Ca2+‐induced Ca2+release initiated by the entry of extracellular Ca2+.
ROLE OF ACTIVATED INTRARENAL REACTIVE OXYGEN SPECIES AND RENIN–ANGIOTENSIN SYSTEM IN IgA NEPHROPATHY MODEL MICE
Authors: Ohashi Naro , Katsurada Akemi , Miyata Kayoko , Satou Ryousuke , Saito Toshie , Urushihara Maki , Kobori Hiroyuki 
Published: March 2009

SUMMARY

Using HIGA (high IgA of ddY) mice as an IgA nephropathy model and BALB/c mice as controls, we demonstrated that reactive oxygen species (ROS) and the renin–angiotensin system (RAS) were activated in kidneys of HIGA mice. However, it was difficult to establish an association between renal damage and changes in ROS and the RAS. Therefore, the present study was performed to determine whether renal injury is associated with changes in ROS and the RAS in HIGA mice.
Male HIGA mice were divided into four groups of 10 each: (i) untreated mice (HIGA + null); (ii) mice treated with the angiotensin AT1 receptor antagonist olmesartan (5 mg/kg per day; HIGA + OLM); (iii) mice treated with the superoxide dismutase mimetic tempol (50 mg/kg per day; HIGA + Tempol); and (iv) mice treated with RAS‐independent antihypertensive drugs (30 mg/kg per day hydralazine, 0.6 mg/kg per day reserpine and 12 mg/kg per day hydrochlorothiazide; HIGA + HRH). Mice were treated for 5 weeks.
Systolic blood pressure decreased significantly in the HIGA + OLM and HIGA + HRH groups, but not in the HIGA + Tempol group, compared with HIGA + null mice. The expression of two ROS markers (4‐hydroxy‐2‐nonenal and heme oxygenase‐1) and angiotensin II as a marker of the RAS decreased significantly in HIGA + OLM and HIGA + Tempol mice, but not in HIGA + HRH mice, compared with HIGA + null mice. As a marker of renal damage, mesangial matrix expansion and the desmin‐positive area decreased significantly in the HIGA + OLM and HIGA + Tempol groups, but not in HIGA + HRH group, compared with the HIGA + null group.
These data suggest that intrarenal ROS and RAS activation play a pivotal role in the development of IgA nephropathy model mice, from the early phase, independent of blood pressure.
Environmental factors and population fluctuations of Akodon azarae (Muridae: Sigmodontinae) in central Argentina
Authors: ANDREO VERÓNICA , PROVENSAL CECILIA , SCAVUZZO MARCELO , LAMFRI MARIO , POLOP JAIME 
Published: March 2009

AbstractThe aim of this work was to explore the relationship between population density of Akodon azarae (Muridae: Sigmodontinae) and climatic and environmental variables, and determine which of them are associated to within and among‐year changes in rodent abundance in agro‐ecosystems from south Córdoba, Argentina. The study was carried out in a rural area of central Argentina, from 1983 to 2003. Density was estimated as a relative density index (RDI). Temperature, precipitation and humidity were obtained from records of the National University of Rio Cuarto. Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature were recorded from National Oceanic and Atmospheric Administration (1983–1998) and Landsat (1998–2003) imagery data sets. We performed simple correlations, multiple regressions and distributed lag analysis. Direct association of climatic and environmental variables with RDI was in general, low. The amount of variability in seasonal changes in density explained by climatic and environmental variables altogether varied from 10% to 70%. Seasonal population fluctuations were influenced by NDVI and rainfall with one and two seasons of delay. Autumn maximum density of the species was also associated with vegetation and rainfall of previous seasons. There also seemed to be an indirect influence of rainfall through vegetation given that we found a positive correlation between them. Results were consistent with basic aspects of the ecology of the species, such as its strong preference for highly covered areas, which provide food and protection from predators, likely increasing its reproductive success. Therefore, in the rural area central Argentina, A. azarae showed seasonal fluctuations with delayed influence of rainfall and vegetation and indirect effects of rainfall.
Arid Recovery – A comparison of reptile and small mammal populations inside and outside a large rabbit, cat and fox‐proof exclosure in arid South Australia
Authors: MOSEBY KATHERINE ELIZABETH , HILL BRYDIE MAY , READ JOHN LLEWELLYN 
Published: March 2009

AbstractAustralian arid zone mammal species within the Critical Weight Range (CWR) of 35 g–5.5 kg have suffered disproportionately in the global epidemic of contemporary faunal extinctions. CWR extinctions have been attributed largely to the effects of introduced or invasive mammals; however, the impact of these threatening processes on smaller mammals and reptiles is less clear. The change in small mammal and reptile assemblages after the removal of rabbits, cats and foxes was studied over a 6‐year period in a landscape‐scale exclosure in the Australian arid zone. Rodents, particularly Notomys alexis and Pseudomys bolami, increased to 15 times higher inside the feral‐proof Arid Recovery Reserve compared with outside sites, where rabbits, cats and foxes were still present. Predation by cats was thought to exert the greatest influence on rodent numbers owing to the maintenance of the disparity in rodent responses through dry years and the differences in dietary preferences between rabbits and P. bolami. The presence of introduced Mus domesticus or medium‐sized re‐introduced mammal species did not significantly affect resident small mammal or reptile abundance. Abundance of most dasyurids and small lizards did not change significantly after the removal of feral animals although reductions in gecko populations inside the reserve may be attributable to second order trophic interactions or subtle changes in vegetation structure and cover. This study suggests that populations of rodent species in northern South Australia below the CWR may also be significantly affected by introduced cats, foxes and/or rabbits and that a taxa specific model of Australian mammal decline may be more accurate than one based on body weight.
Sublethal costs associated with the consumption of toxic prey by snakes
Authors: LLEWELYN JOHN S. , PHILLIPS BENJAMIN L. , SHINE RICHARD 
Published: March 2009

AbstractCosts of plant defences to herbivores have been extensively studied, but costs of chemical defences to carnivores are less well understood. We examine the costs to Australian keelback snakes (Tropidonophis mairii, Gray 1841) of consuming cane toads (Bufo[Rhinella]marinus Linnaeus 1758). Cane toads (an invasive species in Australia) are highly toxic. Although keelbacks can consume toads without dying (unlike most Australian snakes), we show that cane toads are poor quality prey for keelbacks. Toads are of low net nutritional value, take longer to consume than do native frogs and reduce the snake's locomotor performance for up to 6 h after ingestion of a meal. These latter effects may increase a snake's vulnerability to predation. Nutritional content of vertebrate prey is not the only factor driving the evolution of foraging behaviour; other more subtle costs, such as risk of predation, may be widespread.
Causes and consequences of aggregation by neonatal tiger snakes (Notechis scutatus, Elapidae)
Authors: AUBRET FABIEN , SHINE RICHARD 
Published: March 2009

AbstractAlthough snakes traditionally have been regarded as asocial animals, recent studies have revealed complex interactions among neonatal snakes and their mothers. We noticed frequent aggregation by captive neonatal Australian elapids (tiger snakes, Notechis scutatus), and conducted simple experiments to clarify the proximate causation of, and potential consequences of, aggregative behaviour. Litters of neonates exhibited statistically significant aggregation (clustering) in empty containers, especially if the test area was subjected to rapid cooling. Aggregation was most pronounced inside shelter‐sites, and familiar shelters (i.e. containing scent cues from the litter) attracted snakes more than did novel (unscented) shelters. Snakes in larger aggregations cooled more slowly (reflecting their higher combined mass and thus, thermal inertia) and higher body temperatures facilitated neonatal locomotor performance, retreat‐site location and anti‐predator tactics. Plausibly, aggregation in neonatal tiger snakes (and other reptiles) functions to retard cooling rates, with the result that the young snakes are better able to evade or repel attacks by predators.
Fire frequency influences composition and structure of the shrub layer in an Australian subcoastal temperate grassy woodland
Authors: WATSON PENNY J. , BRADSTOCK ROSS A. , MORRIS E. CHARLES 
Published: March 2009

AbstractLittle is known about the relationship between fire regimes and plant diversity in Australia's temperate grassy woodlands. The effect of fire frequency on shrubs in grassy woodland remnants across Western Sydney's Cumberland Plain was examined. Shrub species richness and composition were compared in sites that had experienced a high, moderate or low frequency of fire over the previous 20 years. Nine sites were surveyed, three in each fire frequency category; most sites, including all low‐fire‐frequency sites, had burnt 9–36 months prior to sampling. Fire frequency had a profound effect on the composition and structure of the shrub layer. Per cent frequency and density of the prickly shrub Bursaria spinosa (Pittosporaceae) was considerably higher in low‐fire‐frequency sites than where fires had occurred at least once a decade. In sites where fire had been absent for decades prior to a recent fire, this species dominated the landscape, while elsewhere it occurred as clumps in a grassy matrix. Per cent frequency of other native shrubs, particularly obligate seeders, was greatest at moderate fire frequencies. Exotic shrubs were recorded most often where fire had been rare. While ordination clearly separated out the low‐fire‐frequency sites, complete separation between high‐ and moderate‐fire‐frequency blocks was not achieved. The increase in Bursaria in the absence of fire mirrors the encroachment of woody plants into a range of grassy ecosystems around the world. The sensitivity of obligate seeder species, many of them short‐lived legumes with fire‐cued seeds, to both very frequent and very infrequent fire shows the vulnerability of these species to extreme fire regimes, despite the safeguards conferred by hard‐seededness. Competition from Bursaria, as well as loss of viable seed in the soil, may have contributed to the low frequency of these species after a long inter‐fire interval.
Perceptual stability during dramatic changes in olfactory bulb activation maps and dramatic declines in activation amplitudes
Authors: Homma R. , Cohen L. B. , Kosmidis E. K. , Youngentob S. L. 
Published: March 2009

AbstractWe compared the concentration dependence of the ability of rats to identify odorants with the calcium signals in the nerve terminals of the olfactory receptor neurons. Although identification performance decreased with concentrations both above and below the training stimuli it remained well above random at all concentrations tested (between 0.0006% and 35% of saturated vapor). In contrast, the calcium signals in the same awake animals were much smaller than their maximum values at odorant concentrations <1% of saturated vapor. In addition, maps of activated glomeruli changed dramatically as odorant concentration was reduced. Thus perceptual stability exists in the face of dramatic changes in both the amplitude and the maps of the input to the olfactory bulb. The data for the concentration dependence of the response of the most sensitive glomeruli for each of five odorants was fitted with a Michaelis–Menten (Hill) equation. The fitted curves were extrapolated to odorant concentrations several orders of magnitude lower the smallest observed signals and suggest that the calcium response at low odorant concentrations is > 1000 times smaller than the response at saturating odorant concentrations. We speculate that only a few spikes in olfactory sensory neurons may be sufficient for correct odorant identification.