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Transient
Kinds of Transient Terms modified by Transient Selected AbstractsInvestigation of the Start Transient in a Hall ThrusterCONTRIBUTIONS TO PLASMA PHYSICS, Issue 9-10 2008H. Liu Abstract A two dimensional axisymmetric fully kinetic Particle-in-Cell/Monte Carlo Collision (PIC-MCC) model is used to describe the ignition process in a Hall thruster. A current peak and latter the periodic oscillation of current and electric potential are found. The corresponding evolutions of plasma density, electric potential and atom density during the ignition process are introduced in the paper. In addition, influences of mass flow rate and discharge potential on current peak are modeled and analyzed. The simulated results are consistent with former experimental results. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Start-Up Transient in a Hall ThrusterCONTRIBUTIONS TO PLASMA PHYSICS, Issue 10 2006F. Taccogna Abstract For the first time a two dimensional axisymmetric fully kinetic Particle-in-Cell/Monte Carlo Collision (PICMCC) model is used to describe the start-up transient of the acceleration channel in a Hall thruster. The Poisson equation and a secondary electron emission model are invoked for the description of the plasma dynamic phase. Numerical results have been used to see the formation and evolution of the discharge inside the channel. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Pathological dissociation and neuropsychological functioning in borderline personality disorderACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2009V. Ø. Haaland Objective:, Transient, stress-related severe dissociative symptoms or paranoid ideation is one of the criteria defining the borderline personality disorder (BPD). Examinations of the neuropsychological correlates of BPD reveal various findings. The purpose of this study was to investigate the association between dissociation and neuropsychological functioning in patients with BPD. Method:, The performance on an extensive neuropsychological battery of patients with BPD with (n = 10) and without (n = 20) pathological dissociation was compared with that of healthy controls (n = 30). Results:, Patients with pathological dissociation were found to have reduced functioning on every neuropsychological domain when compared with healthy controls. Patients without pathological dissociation were found to have reduced executive functioning, but no other differences were found. Conclusion:, Pathological dissociation is a clinical variable that differentiates patients with BPD with regard to cognitive functioning. [source] Spatial Analysis of the Factors Contributing to the Relationship between the Transient, Meridional Eddy Sensible, and Latent Heat Flux in the Southern HemisphereGEOGRAPHICAL ANALYSIS, Issue 2 2000Marilyn Raphael In this paper principal component analysis (PCA) and singular value decomposition (SVD) are used to define the importance of the variables contributing to the relationship between the transient latent and sensible heat fluxes and to show their temporal and spatial variation. SVD is offered as an alternative means of isolating spatial and temporal structures in data with the advantage that it can depict simultaneous space-time variations that are aggregates of the results produced by PCA. Both methods of analysis produced two very important uncorrelated modes of variability in January and July, indicating that the transient heat fluxes are influenced by few controlling factors. We suggest that these modes of variability represent the influences of the meridional temperature gradient, atmospheric moisture, and activity within the source and sink regions of the transient heat fluxes. The physical relationships between the heat fluxes that appear to represented by the statistical modes of variability are discussed. [source] Importance of Unsaturated Zone Flow for Simulating Recharge in a Humid ClimateGROUND WATER, Issue 4 2008Randall J. Hunt Transient recharge to the water table is often not well understood or quantified. Two approaches for simulating transient recharge in a ground water flow model were investigated using the Trout Lake watershed in north-central Wisconsin: (1) a traditional approach of adding recharge directly to the water table and (2) routing the same volume of water through an unsaturated zone column to the water table. Areas with thin (less than 1 m) unsaturated zones showed little difference in timing of recharge between the two approaches; when water was routed through the unsaturated zone, however, less recharge was delivered to the water table and more discharge occurred to the surface because recharge direction and magnitude changed when the water table rose to the land surface. Areas with a thick (15 to 26 m) unsaturated zone were characterized by multimonth lags between infiltration and recharge, and, in some cases, wetting fronts from precipitation events during the fall overtook and mixed with infiltration from the previous spring snowmelt. Thus, in thicker unsaturated zones, the volume of water infiltrated was properly simulated using the traditional approach, but the timing was different from simulations that included unsaturated zone flow. Routing of rejected recharge and ground water discharge at land surface to surface water features also provided a better simulation of the observed flow regime in a stream at the basin outlet. These results demonstrate that consideration of flow through the unsaturated zone may be important when simulating transient ground water flow in humid climates with shallow water tables. [source] Performance characterization of a non-linear system as both an adaptive notch filter and a phase-locked loopINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 1 2004M. Karimi-Ghartemani Abstract The behaviour of a non-linear dynamical system is described. The system may be characterized as an adaptive notch filter, or alternatively, as a phase-locked loop. Either way, the system has the inherent capability of directly providing estimates of the parameters of the extracted sinusoidal component of its input signal, namely its amplitude, phase and frequency. The structure and mathematical properties of the system are presented for two cases of fixed-frequency and varying-frequency operation. The effects of parameter setting of the system on its performance are studied in detail using computer simulations. Transient and steady-state behaviour of the system are studied in the presence of noise. Simplicity of structure, high noise immunity and robustness and the capability of direct estimation of amplitude, phase and frequency are the salient features of the system when envisaged as an adaptive notch filter or a phase-locked loop. Copyright © 2004 John Wiley & Sons, Ltd. [source] RNAi-mediated MEK1 knock-down prevents ERK1/2 activation and abolishes human hepatocarcinoma growth in vitro and in vivoINTERNATIONAL JOURNAL OF CANCER, Issue 6 2010Luc Gailhouste Abstract The mitogen-activated protein kinases MEK/ERK pathway regulates fundamental processes in malignant cells and represents an attractive target in the development of new cancer treatments especially for human hepatocarcinoma highly resistant to chemotherapy. Although gene extinction experiments have suggested distinct roles for these proteins, the MEK/ERK cascade remains widely considered as exhibiting an overlap of functions. To investigate the functionality of each kinase in tumorigenesis, we have generated stably knock-down clones for MEK1/2 and ERK1/2 isoforms in the human hepatocellular carcinoma line HuH7. Our results have shown that RNAi strategy allows a specific disruption of the targeted kinases and argued for the critical function of MEK1 in liver tumor growth. Transient and stable extinction experiments demonstrated that MEK1 isoform acts as a major element in the signal transduction by phosphorylating ERK1 and ERK2 after growth factors stimulation, whereas oncogenic level of ERK1/2 phosphorylation appears to be MEK1 and MEK2 dependent in basal condition. In addition, silencing of MEK1 or ERK2 abolished cell proliferation and DNA replication in vitro as well as tumor growth in vivo after injection in rodent. In contrast, targeting MEK2 or ERK1 had no effect on hepatocarcinoma progression. These results strongly corroborate the relevance of targeting the MEK cascade as attested by pharmacologic drugs and support the potential application of RNAi in future development of more effective cancer therapies. Our study emphasizes the importance of the MEK/ERK pathway in human hepatocarcinoma cell growth and argues for a crucial role of MEK1 and ERK2 in this regulation. [source] Alteration of amino acid metabolism in neuronal aggregate cultures exposed to hypoglycaemic conditionsJOURNAL OF NEUROCHEMISTRY, Issue 6 2002Paul Honegger Abstract The neuronal effects of glucose deficiency on amino acid metabolism was studied on three-dimensional cultures of rat telencephalon neurones. Transient (6 h) exposure of differentiated cultures to low glucose (0.25 mm instead of 25 mm) caused irreversible damage, as judged by the marked decrease in the activities of two neurone-specific enzymes and lactate dehydrogenase, 1 week after the hypoglycemic insult. Quantification of amino acids and ammonia in the culture media supernatants indicated increased amino acid utilization and ammonia production during glucose-deficiency. Measurement of intracellular amino acids showed decreased levels of alanine, glutamine, glutamate and GABA, while aspartate was increased. Added lactate (11 mm) during glucose deficiency largely prevented the changes in amino acid metabolism and ammonia production, and attenuated irreversible damage. Higher media levels of glutamine (4 mm instead of 0.25 mm) during glucose deprivation prevented the decrease of intracellular glutamate and GABA, while it further increased intracellular aspartate, ammonia production and neuronal damage. Both lactate and glutamine were readily oxidized in these neuronal cultures. The present results suggest that in neurones, glucose deficiency enhances amino acid deamination at the expense of transamination reactions. This results in increased ammonia production and neuronal damage. [source] Fast Effects of Glucocorticoids on Memory-Related Network Oscillations in the Mouse HippocampusJOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2008E. K. Weiss Transient or lasting increases in glucocorticoids accompany deficits in hippocampus-dependent memory formation. Recent data indicate that the formation and consolidation of declarative and spatial memory are mechanistically related to different patterns of hippocampal network oscillations. These include gamma oscillations during memory acquisition and the faster ripple oscillations (approximately 200 Hz) during subsequent memory consolidation. We therefore analysed the effects of acutely applied glucocorticoids on network activity in mouse hippocampal slices. Evoked field population spikes and paired-pulse responses were largely unaltered by corticosterone or cortisol, respectively, despite a slight increase in maximal population spike amplitude by 10 ,m corticosterone. Several characteristics of sharp waves and superimposed ripple oscillations were affected by glucocorticoids, most prominently the frequency of spontaneously occurring sharp waves. At 0.1 ,m, corticosterone increased this frequency, whereas maximal (10 ,m) concentrations led to a reduction. In addition, gamma oscillations became slightly faster and less regular in the presence of high doses of corticosteroids. The present study describes acute effects of glucocorticoids on sharp wave-ripple complexes and gamma oscillations in mouse hippocampal slices, revealing a potential background for memory deficits in the presence of elevated levels of these hormones. [source] Transient versus prolonged hyperlocomotion following lateral fluid percussion injury in mongolian gerbilsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2006Shihong Li Abstract Posttraumatic hyperactivity is a neurobehavioral symptom commonly seen in patients after traumatic brain injury (TBI). No useful animal model has yet been established for evaluation of this important symptom. We induced either mild (MILD, 0.7,0.9 atm) or moderate (MOD, 1.3,1.6 atm) lateral fluid percussion injury (LFPI) in Mongolian gerbils. Open-field and T-maze tests were used during a 7-day period after the trauma. All animals were perfusion fixed for histopathological examinations. Transient locomotor hyperactivity was found with a peak at 6 hr after injury in the MILD animals, whereas MOD animals showed prolonged and severe hyperlocomotion throughout the 7-day posttrauma period (P < 0.0001). Interestingly, the temporal profile of the posttraumatic hyperactivity was similar to that of the working memory deficit in both injury groups. Histological examination revealed significant neural tissue damages, including cortical necrosis, white matter rarefaction, and neuronal loss in the hippocampus in the ipsilateral hemisphere of the MOD animals, vs. only negligible changes in the MILD animals. Correlation analysis revealed that the volume of white matter lesions was significantly correlated with both posttraumatic hyperactivity (r = 0.591, P < 0.01) and working memory deficit (r = ,0.859, P < 0.0001). Taken together, our findings confirm the successful reproduction of posttraumatic hyperactivity following experimental TBI. The posttraumatic hyperlocomotion probably shared pathomechanisms common to those of cognitive dysfunction caused by LFPI, supporting the speculation from previous studies that some neurobehavioral abnormities intimately correlate with TBI-induced cognitive dysfunction. Histopathologically, significant involvement of white matter damage in the posttraumatic functional deficits was indicated. © 2006 Wiley-Liss, Inc. [source] Macrofauna Communities in the Eastern Mediterranean Deep SeaMARINE ECOLOGY, Issue 3 2003Ingrid Kröncke Abstract., During two expeditions with RV ,Meteor' in summer 1993 and winter 1997/98 the structural and functional diversity of the benthic system of the highly oligotrophic eastern Mediterranean deep sea was investigated. The macrofauna communities were dominated by polychaetes even at the deepest stations. The fauna at shallow stations was dominated by surface deposit feeders, whereas subsurface deposit feeders and predators generally increased with depth. A high percentage of suspension-feeding Porifera was found in the Levantine Basin. Mean abundance and number of taxa of both expeditions were significantly correlated to depth and distance to the nearest coast as well as to the total organic carbon (TOC) content in sediments. Numbers of taxa and abundance decreased generally with depth, although lowest numbers were not found at the deepest stations but in the extremely oligotrophic Levantine and Ierapetra Basin. Biomass measured during the second cruise was extremely low in the Ierapetra Basin and comparable to other extreme oligotrophic seas. The significant correlations found for TOC contents and macrofauna with distance to coast during both expeditions apparently reflect the role of hydrographically governed transport of organic matter produced in coastal regions into greater and extreme depths of the Mediterranean Sea. Seasonal differences in macrofauna communities due to seasonal differences in food supply were not found. However, recent large-scale hydrographic changes (Eastern Mediterranean Transient, EMT) might change the oligotrophy and, thus, the structure of the benthic communities in the Eastern Mediterranean deep sea. [source] Unusual glitch activity in the RRAT J1819,1458: an exhausted magnetar?MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2009A. G. Lyne ABSTRACT We present an analysis of regular timing observations of the high magnetic field Rotating Radio Transient (RRAT) J1819,1458 obtained using the 64-m Parkes and 76-m Lovell radio telescopes over the past 5 years. During this time, the RRAT has suffered two significant glitches with fractional frequency changes of 0.6 × 10,6 and 0.1 × 10,6. Glitches of this magnitude are a phenomenon displayed by both radio pulsars and magnetars. However, the behaviour of J1819,1458 following these glitches is quite different to that which follows glitches in other neutron stars, since the glitch activity resulted in a significant long-term net decrease in the slow-down rate. If such glitches occur every 30 years, the spin-down rate, and by inference the magnetic dipole moment, will drop to zero on a time-scale of a few thousand years. There are also significant increases in the rate of pulse detection and in the radio pulse energy immediately following the glitches. [source] Discovery of a short orbital period in the Supergiant Fast X-ray Transient IGR J16479,4514MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2009Chetana Jain ABSTRACT We report here the discovery of a 3.32 d orbital period in the Supergiant Fast X-ray Transient (SFXT) source IGR J16479,4514. Using the long-term light curve of this source obtained with Swift Burst Alert Telescope (BAT) in the energy range of 15,50 keV, we have clearly detected an orbital modulation including a full eclipse of duration ,0.6 d. In the hard X-ray band of the BAT instrument, the eclipse ingress and egress are rapid. We have also used the long-term light curve obtained with the Rossi X-ray Timing Explorer (RXTE) All Sky Monitor (ASM) in the energy range of 1.5,12 keV. Taken independently, the detection of orbital modulation in the RXTE,ASM light curve is not significant. However, considering a clear detection of orbital modulation in the BAT light curve, we have used the ASM light curve for a more precise determination of the orbital period. IGR J16479,4514 has the shortest orbital period among the three SFXTs with measured/known orbital period. We discuss the implication of a short orbital period with the various mechanisms proposed to explain the transient nature of this class of sources. [source] Safety of Pacemaker Implantation Prior to Radiofrequency Ablation of Atrioventricular Junction in a Single Session ProcedurePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2000ALESSANDRO PROCLEMER RF current delivery may cause acute and chronic dysfunction of previously implanted pacemakers. The aim of this study was to assess prospectively the effects of RF energy on Thera I and Kappa pacemakers in 70 consecutive patients (mean age 70 ± 11 years, mean left ventricular ejection fraction 48 ± 15%) who underwent RF ablation of the AV junction for antiarrhythmic drug refractory atrial fibrillation (permanent in 42 patients, paroxysmal in 28). These pacing systems incorporate protection elements to avoid electromagnetic interference. The pacemakers (Thera DR 7960 I in 20 patients, Thera SR 8960 1 in 30, Kappa DR 600,601 in 8, Kappa SR 700,701 in 12) were implanted prior to RF ablation in a single session procedure and were transiently programmed to VVI mode at a rate of 30 beats/min. Capsure SP and Z unibipolar leads were used. During RF application there was continuous monitoring of three ECG leads, endocavitary electrograms, and event markers. Complete AV block was achieved in all cases after 3.6 ± 2.9 RF pulses and 100 ± 75 seconds of RF energy delivery. The mean time of pacemaker implantation and RF ablation was 60 ± 20 minutes. Transient or permanent pacemaker dysfunction including under/oversensing, reversion to a "noise-mode" pacing, pacing inhibition, reprogramming, or recycling were not observed. Leads impedance, sensing, and pacing thresholds remained in the normal range in the acute and long-term phase (average follow-up 18 ± 12 months). In conclusion, Thera I and Kappa pacemakers exhibit excellent protection against interference produced by RF current. The functional integrity of the pacemakers and Capsure leads was observed in the acute and chronic phases. Thus, the implantation of these pacing systems prior to RF ablation of the AV junction can be recommended. [source] Localization of a flavonoid biosynthetic polyphenol oxidase in vacuolesTHE PLANT JOURNAL, Issue 2 2006Eiichiro Ono Summary Aureusidin synthase, a polyphenol oxidase (PPO), specifically catalyzes the oxidative formation of aurones from chalcones, which are plant flavonoids, and is responsible for the yellow coloration of snapdragon (Antirrhinum majus) flowers. All known PPOs have been found to be localized in plastids, whereas flavonoid biosynthesis is thought to take place in the cytoplasm [or on the cytoplasmic surface of the endoplasmic reticulum (ER)]. However, the primary structural characteristics of aureusidin synthase and some of its molecular properties argue against localization of the enzyme in plastids and the cytoplasm. In this study, the subcellular localization of the enzyme in petal cells of the yellow snapdragon was investigated. Sucrose-density gradient and differential centrifugation analyses suggested that the enzyme (the 39-kDa mature form) is not located in plastids or on the ER. Transient assays using a green fluorescent protein (GFP) chimera fused with the putative propeptide of the PPO precursor suggested that the enzyme was localized within the vacuole lumen. We also found that the necessary information for vacuolar targeting of the PPO was encoded within the 53-residue N-terminal sequence (NTPP), but not in the C-terminal sequence of the precursor. NTPP-mediated ER-to-Golgi trafficking to vacuoles was confirmed by means of the co-expression of an NTPP-GFP chimera with a dominant negative mutant of the Arabidopsis GTPase Sar1 or with a monomeric red fluorescent protein (mRFP)-fused Golgi marker (an H+ -translocating inorganic pyrophosphatase of Arabidopsis). We identified a sequence-specific vacuolar sorting determinant in the NTPP of the precursor. We have demonstrated the biosynthesis of a flavonoid skeleton in vacuoles. The findings of this metabolic compartmentation may provide a strategy for overcoming the biochemical instability of the precursor chalcones in the cytoplasm, thus leading to the efficient accumulation of aurones in the flower. [source] Transient Left Ventricular Basal Ballooning,"Inverted" Tako-tsuboCLINICAL CARDIOLOGY, Issue 7 2009Vicens Marti MD No abstract is available for this article. [source] Early motor development of premature infants with birthweight less than 2000 gramsACTA PAEDIATRICA, Issue 12 2000SJ Pedersen The aim was to assess motor function during infancy in order to predict later function, mainly cerebral palsy. The neuromotor development of a population-based cohort of 209 of 236 (89%) survivors with a birthweight less than 2000 g was assessed using the Infant Neurological International Battery (INFANIB) and detailed neurological assessment. The infants were classified as being normal, dystonic, hypotonic or having suspected cerebral palsy (CP) at 4, 7, 13 and 18 mo corrected age if birthweight was less than 1500 g (n= 119) and at 7 and 13 mo if birthweight was 1500,1999 g (n= 90). Those with dystonia or suspected CP were followed until diagnosed as normal or as having CP after at least 36 mo of age. Fourteen (7%) finally developed CP. Motor function at 4 mo was inaccurate in predicting function at 7 mo and later. All who were normal at 7 mo remained normal in the follow-up period. Eight of 65 who were dystonic at 7 mo developed suspected CP, and three judged as suspected CP were eventually normal. The 14 who developed CP were judged as suspected CP (n= 5) or dystonic (n= 8) and one as hypotonic at 7 mo of age. Conclusions: The specificity of motor evaluation at 7 mo corrected age regarding CP is unsatisfactory, since dystonia at this age is most often transient. A normal neuromotor assessment at 7 mo is highly predictive of subsequent normal motor function. [source] The Neutralizer: a self-configurable failure detector for minimizing distributed storage maintenance costCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 2 2009Zhi Yang Abstract To achieve high data availability or reliability in an efficient manner, distributed storage systems must detect whether an observed node failure is permanent or transient, and if necessary, generate replicas to restore the desired level of replication. Given the unpredictability of network dynamics, however, distinguishing permanent and transient failures is extremely difficult. Though timeout-based detectors can be used to avoid mistaking transient failures as permanent failures, it is unknown how the timeout values should be selected to achieve a better tradeoff between detection latency and accuracy. In this paper, we address this fundamental tradeoff from several perspectives. First, we explore the impact of different timeout values on maintenance cost by examining the probability of their false positives and false negatives. Second, we propose a self-configurable failure detector called the Neutralizer based on the idea of counteracting false positives with false negatives. The Neutralizer could enable the system to maintain a desired replication level on average with the least amount of bandwidth. We conduct extensive simulations using real trace data from a widely deployed peer-to-peer system and synthetic traces based on PlanetLab and Microsoft PCs, showing a significant reduction in aggregate bandwidth usage after applying the Neutralizer (especially in an environment with a low average node availability). Overall, we demonstrate that the Neutralizer closely approximates the performance of a perfect ,oracle' detector in many cases. Copyright © 2008 John Wiley & Sons, Ltd. [source] Regional variations in action potential alternans in isolated murine Scn5a+/, hearts during dynamic pacingACTA PHYSIOLOGICA, Issue 2 2010G. D. K. Matthews Abstract Aim:, Clinical observations suggest that alternans in action potential (AP) characteristics presages breakdown of normal ordered cardiac electrical activity culminating in ventricular arrhythmogenesis. We compared such temporal nonuniformities in monophasic action potential (MAP) waveforms in left (LV) and right ventricular (RV) epicardia and endocardia of Langendorff-perfused murine wild-type (WT), and Scn5a+/, hearts modelling Brugada syndrome (BrS) for the first time. Methods:, A dynamic pacing protocol imposed successively incremented steady pacing rates between 5.5 and 33 Hz. A signal analysis algorithm detected sequences of >10 beats showing alternans. Results were compared before and following the introduction of flecainide (10 ,m) and quinidine (5 ,m) known to exert pro- and anti-arrhythmic effects in BrS. Results:, Sustained and transient amplitude and duration alternans were both frequently followed by ventricular ectopic beats and ventricular tachycardia or fibrillation. Diastolic intervals (DIs) that coincided with onsets of transient (tr) or sustained (ss) alternans in MAP duration (DI*) and amplitude (DI,) were determined. Kruskal,Wallis tests followed by Bonferroni-corrected Mann,Whitney U -tests were applied to these DI results sorted by recording site, pharmacological conditions or experimental populations. WT hearts showed no significant heterogeneities in any DI. Untreated Scn5a+/, hearts showed earlier onsets of transient but not sustained duration alternans in LV endocardium compared with RV endocardium or LV epicardium. Flecainide administration caused earlier onsets of both transient and sustained duration alternans selectively in the RV epicardium in the Scn5a+/, hearts. Conclusion:, These findings in a genetic model thus implicate RV epicardial changes in the arrhythmogenicity produced by flecainide challenge in previously asymptomatic clinical BrS. [source] Patch Occupancy and Potential Metapopulation Dynamics of Three Forest Mammals in Fragmented Afromontane Forest in South AfricaCONSERVATION BIOLOGY, Issue 4 2000Michael J. Lawes We recorded patch occupancy of blue duiker ( Philantomba monticola), tree hyrax ( Dendrohyrax arboreus), and samango monkey (Cercopithecus mitis labiatus) in 199 forest patches. Their rarity is ascribed to the fragmentation and destruction of their forest habitat. Incidence functions, derived from presence and absence data, were formulated as generalized linear models, and environmental effects were included in the fitted logistic models. The small and mostly solitary hyrax and duiker persisted in smaller patches than the large and social monkey. Although this result follows expectations based on relative home-range sizes of each species, the incidence probability of the samango monkey was invariant with increasing isolation, whereas a gradual decrease with increasing isolation was observed for the hyrax and duiker. Group dynamics may inhibit dispersal and increase the isolation effect in social species such as samango monkeys. A mainland-island metapopulation model adequately describes patterns of patch occupancy by the hyrax and duiker, but the monkeys' poor dispersal ability and obvious area-dependent extirpation suggest that they exist in transient, nonequilibrium (declining) metapopulations. Through identification of large forest patches for careful protection and management, the survival of all three species,especially the monkey,could be prolonged. Because no functional metapopulation may exist for the monkey, however, this is an emergency measure. For the duiker and hyrax, larger patches should form part of a network of smaller and closer patches in a natural matrix. Resumen: Investigamos la persistencia de tres mamíferos forestales raros de tamaño mediano (2,9 kg) en los bosques fragmentados de cinturón de niebla Podocarpus en la región central de la provincia KwaZulu-Natal, Sudáfrica. Registramos la ocupación del duiker azul ( Philantomba monticola), el hyrax arborícola ( Dendrohyrax arboreus) y el mono samango (Cercopithecus mitis labiatus) en 199 parches forestales. Su rareza se atribuye a la fragmentación y destrucción de su hábitat forestal. Las funciones de incidencia, derivadas de datos de presencia y ausencia, fueron formuladas como modelos lineales generalizados, y los efectos ambientales fueron incluidos en los modelos logísticos ajustados. Los pequeños y mayormente solitarios hyrax y duiker persistieron en parches más pequeños que los monos, que son más grandes y más sociables. A pesar de que este resultado obedece a expectativas basadas en tamaños de rango de hogar relativos de cada especie, la probabilidad de incidencia del mono samango no cambió con un incremento en el aislamiento, mientras que una disminución gradual al crecer el aislamiento se observó en hyrax y duiker. Las dinámicas de grupos podrían inhibir la dispersión e incrementar el efecto de aislamiento en especies sociables como lo es el mono samango. Un modelo de metapoblación continente-isla describe adecuadamente los patrones de la ocupación de parches por hyrax y duiker; sin embargo, la pobre capacidad de dispersión de los monos y la obvia extirpación área-dependente sugiere que estos existen en metapoblaciones transitorias, desequilibradas (en disminución). Mediante la identificación de parches forestales grandes para la protección y manejo cuidadosos, la supervivencia de las tres especies ( pero especialmente la de los monos) podría ser prolongada. Sin embargo, debido a que no existen metapoblaciones funcionales de monos, esta es una medida de emergencia. Para el duiker y el hyrax, los parches grandes deberán formar parte de una red de parches más pequeños y más cercanos en una matriz natural. [source] The decrease in electrically evoked force production is delayed by a previous bout of stretch,shortening cycle exerciseACTA PHYSIOLOGICA, Issue 1 2010S. Kamandulis Abstract Aim:, Unaccustomed physical exercise with a large eccentric component is accompanied by muscle damage and impaired contractile function, especially at low stimulation frequencies. A repeated bout of eccentric exercise results in less damage and improved recovery of contractile function. Here we test the hypotheses that (1) a prior stretch,shortening cycle (SSC) exercise protects against impaired muscle function during a subsequent bout of SSC exercise and (2) the protection during exercise is transient and becomes less effective as the exercise progresses. Methods:, Healthy untrained men (n = 7) performed SSC exercise consisting of 100 maximal drop jumps at 30 s intervals. The same exercise was repeated 4 weeks later. Peak quadriceps muscle force evoked by electrical stimulation at 15 (P15) and 50 (P50) Hz was measured before exercise, after 10, 25, 50 and 100 jumps as well as 1 and 24 h after exercise. Results:, P15 and P50 were higher during the initial phase of the repeated bout compared with the first exercise bout, but there was no difference between the bouts at the end of the exercise periods. P15 and P50 were again larger 24 h after the repeated bout. The P15/P50 ratio during exercise was not different between the two bouts, but it was higher after the repeated bout. Conclusion:, A prior bout of SSC exercise temporarily protects against impaired contractile function during a repeated exercise bout. The protection can again be seen after exercise, but the underlying mechanism then seems to be different. [source] Start-Up Transient in a Hall ThrusterCONTRIBUTIONS TO PLASMA PHYSICS, Issue 10 2006F. Taccogna Abstract For the first time a two dimensional axisymmetric fully kinetic Particle-in-Cell/Monte Carlo Collision (PICMCC) model is used to describe the start-up transient of the acceleration channel in a Hall thruster. The Poisson equation and a secondary electron emission model are invoked for the description of the plasma dynamic phase. Numerical results have been used to see the formation and evolution of the discharge inside the channel. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Modulation of antigen expression in B-cell precursor acute lymphoblastic leukemia during induction therapy is partly transient: Evidence for a drug-induced regulatory phenomenon.CYTOMETRY, Issue 3 2010Results of the AIEOP-BFM-ALL-FLOW-MRD-Study Group Abstract Background: Changes of antigen expression on residual blast cells of acute lymphoblastic leukemia (ALL) occur during induction treatment. Many markers used for phenotyping and minimal residual disease (MRD) monitoring are affected. Glucocorticoid (GC)-induced expression modulation has been causally suspected, however, subclone selection may also cause the phenomenon. Methods: We investigated this by following the phenotypic evolution of leukemic cells with flow cytometry from diagnosis to four time points during and after GC containing chemotherapy in the 20 (of 360 consecutive) B-cell precursor patients with ALL who had persistent MRD throughout. Results: The early expression changes of CD10 and CD34 were reversible after stop of GC containing chemotherapy. Modulation of CD20 and CD45 occurred mostly during the GC phase, whereas CD11a also changed later on. Blast cells at diagnosis falling into gates designed according to "shifted" phenotypes from follow-up did not form clusters and were frequently less numerous than later on. Conclusions: Our data support the idea that drug-induced modulation rather than selection causes the phenomenon. The good message for MRD assessment is that modulation is transient in at least two (CD10 and CD34) of the five prominent antigens investigated and reverts to initial aberrant patterns after stop of GC therapy, whereas CD20 expression gains new aberrations exploitable for MRD detection. © 2010 Clinical Cytometry Society [source] The motility of glioblastoma tumour cells is modulated by intracellular cofilin expression in a concentration-dependent mannerCYTOSKELETON, Issue 3 2005Celestial T. Yap Abstract The invasive behaviour of tumour cells has been attributed in part to dysregulated cell motility. Members of the ADF/Cofilin family of actin-binding proteins are known to increase microfilament dynamics by increasing the rate at which actin monomers leave the pointed end of the filament and by a filament-severing activity. As depolymerisation is a rate-limiting step in actin dynamics, ADF/Cofilins are suspected to facilitate the motility of cells. To test this, we investigated the influence of cofilin on tumour motility by transient and stably overexpressing cofilin in the human glioblastoma cell line, U373 MG. Several different methods were used to ascertain the level of cofilin in overexpressing clones and this was correlated with their rate of random locomotion. A biphasic relationship between cofilin level and locomotory rate was found. Clones that displayed a moderate amount of overproduction of cofilin were found to have increased rates of locomotion approximately linear to the overproduction of cofilin up to an optimal cofilin level of about 4.5 times that of wild type cells at which the cells were almost twice as fast. However, clones producing more than this optimal amount were found to locomote at progressively reduced speeds. Cells that overexpress cofilin have reduced stress fibres compared to control cells showing that the excess cofilin affects the actin cytoskeleton. We conclude that overexpression of cofilin enhances the motility of glioblastoma tumour cells in a concentration-dependent fashion, which is likely to contribute to their invasiveness. Cell Motil. Cytoskeleton 60:153,165, 2005. © 2005 Wiley-Liss, Inc. [source] Trichloroacetic Acid Matricectomy in the Treatment of Ingrowing ToenailsDERMATOLOGIC SURGERY, Issue 6 2009SU-HAN KIM MD BACKGROUND Ingrowing toenails can be treated with conservative therapy or surgery, but frequent relapse can be a problem in conservative therapy and surgical therapy without matricectomy. Thus, permanent nail ablation by partial matricectomy is now accepted as the treatment of choice. OBJECTIVE To evaluate the efficacy and safety of trichloroacetic acid (TCA) matricectomy in the treatment of ingrowing nail. MATERIALS AND METHODS Forty ingrowing toenail edges in 25 patients were enrolled. TCA matricectomy with 100% trichloroacetic acid after partial nail avulsion was performed. For a few weeks after surgery, postoperative complications such as pain, discharge, and infection were assessed. After a mean follow-up period of 22.9 months, recurrence rate and cosmetic outcomes were investigated to evaluate the effects of the surgery. RESULTS The wounds almost always healed within 2 weeks without prolonged exudative discharge. Pain was mild and transient. A case of secondary infection occurred. Recurrence was found in only two nails of one patient, and the success rate was 95%, with good cosmetic results. CONCLUSION TCA matricectomy showed a low recurrence rate with minimal side effects and was easy to perform in outpatient clinic. Therefore, it may be a good alternative treatment of ingrowing toenails. [source] Short-Term Side Effects of Fractional PhotothermolysisDERMATOLOGIC SURGERY, Issue 2005Galen H. Fisher MD Objective:. To ascertain the immediate and short-term side effects of fractional photothermolysis for the treatment of a variety of skin disorders involving the face, neck, chest, and hands. Methods. Physician-administered questionnaires were given during 60 follow-up visits for fractional photothermolysis treatment for a variety of facial skin disorders in patients with skin types ranging from I to IV. The questionnaire addressed 14 possible side effects, pain, and limitation of social activities. In addition, all patients were asked about any additional side effects not mentioned in the survey. An analysis of the data was performed once 60 surveys had been collected. Results. All patients (100%) undergoing fractional photothermolysis had transient post-treatment erythema. Other frequently reported post-treatment side effects were transient and included facial edema (82%), dry skin (86.6%), flaking (60%), a few (one to three) small, superficial scratches (46.6%), pruritis (37%), and bronzing (26.6%). Other more rarely reported effects included transient increased sensitivity (10%) and acneiform eruption (10%). Most patients reported that the pain level was easily tolerated, with an average pain score of 4.6 on a scale of 10. Most patients (72%) reported limiting social engagements for an average of 2 days after treatment. There were no long-lasting adverse events noted in our survey. Conclusion. Fractional photothermolysis to treat dermatologic conditions on the face, neck, chest, and hands is a well-tolerated and safe procedure with several immediate, and slightly delayed, post-treatment side effects. In our experience, these side effects were transient and limited to erythema, edema, dry skin, flaking skin, superficial scratches, pruritis, increased sensitivity, and acneiform eruption. Importantly, we did not see the development of post-treatment scarring, herpetic activation, hypopigmentation, hyperpigmentation, persistent erythema, persistent edema, or infection. [source] Botulinum Toxin for the Treatment of Facial FlushingDERMATOLOGIC SURGERY, Issue 1 2004Melanie Yuraitis MS Background. Facial flushing is a common problem that is encountered by fair-skinned patients of Celtic and Northern European descent. Although usually transient in nature, some patients display a persistent reddened skin tone, with periods of increased erythema. Treatment of this condition is limited. Objective. To describe a novel method for the treatment of persistent facial flushing. Method. We report a case of persistent facial flushing that was resistant to multiple pulsed dye laser treatments and was successfully treated with botulinum toxin A. Results. The posttreatment appearance was dramatic, and the patient was highly satisfied with the cosmetic outcome. Conclusion. Botulinum toxin A can be used in small quantities to decrease persistent facial flushing temporarily. [source] Botulinum Toxin Type B for Dynamic Glabellar Rhytides Refractory to Botulinum Toxin Type ADERMATOLOGIC SURGERY, Issue 5 2003Tina S. Alster MD Background. Botulinum toxin type B (BTX-B; Myobloc) has recently been introduced for the treatment of dynamic rhytides. This serotype is structurally similar to botulinum toxin type A (BTX-A; Botox) and appears to produce equivalent muscular paralysis. Because of the fact that some patients may become resistant to the effects of BTX-A with its continued use or may require large doses of type A to exert adequate muscular paralysis, the use of BTX-B may prove beneficial in these cases. Objective. To determine the effect of BTX-B on glabellar rhytides refractory or showing decreased clinical effect to treatment with BTX-A. Methods. Twenty females (mean age, 43 years) with vertical glabellar rhytides showing decreased or negligible clinical effect to BTX-A were treated with intramuscular injections of BTX-B. Five standardized intramuscular sites (procerus, inferomedial corrugator muscles, superior middle corrugator muscles) received a total dose of 2,500 U. Patients were evaluated at pretreatment and 48 to 72 hours, 1 week, and 2 and 4 months after injection. Results. All glabellar rhytides improved after treatment with BTX-B injections. Peak clinical effect was noted 1 month after treatment, with 50% of peak effect evident at the 2-month follow-up. Near complete dissolution of effect was seen at 4 months after treatment. Side effects were transient and were limited to moderate injectional pain and rare bruising and frontal brow tightness. Conclusions. BTX-B is an effective treatment modality for glabellar rhytides refractory or exhibiting decreased clinical effect to BTX-A. The duration of effect using the 2,500 U dosing schedule described herein was shorter than that typically achieved after equivalent BTX-A injection. [source] An overview of human papillomavirus infection for the dermatologist: disease, diagnosis, management, and preventionDERMATOLOGIC THERAPY, Issue 5 2010Michelle Forcier ABSTRACT Genital human papillomavirus (HPV) is a common, usually transient, dermatologic infection transmitted by genital contact that can cause a variety of anogenital diseases, including warts (condyloma), dysplasia (cervical, vaginal, vulvar, anal), and squamous cell carcinoma. A number of treatment modalities are available to treat anogenital warts, both patient- and provider-applied. Treatment is efficacious, but lesions can recur. Bivalent and quadrivalent vaccines are approved to prevent HPV infection. Both are indicated to prevent cervical cancer, while the quadrivalent vaccine is also approved to prevent vaginal/vulvar cancers as well as genital warts in males and females. Providers should clearly explain the natural history and potential sequelae of HPV disease, counsel patients on prevention strategies, and recommend vaccination as an effective method of prevention to their patients. [source] The Challenge to the State in a Globalized WorldDEVELOPMENT AND CHANGE, Issue 5 2002Christopher Clapham Individual instances of state failure and collapse must be placed within a broader appreciation of the evolution of statehood within the international system. The idea that the inhabited area of the globe must be divided between sovereign states is a recent development, and likely to prove a transient one. Largely the product of European colonialism, and turned into a global norm by decolonization, it is threatened both by the inherent difficulties of state maintenance, and by processes inherent in globalization. States are expensive organizations to maintain, not only in economic terms but also in the demands that they make on their citizens and their own employees. Poor and dispersed peoples, and those whose values derive from societies without states, have found these demands especially burdensome. The end of the Cold War and the collapse of the Soviet Union revealed the hollowness of existing models of sovereign states, and challenged the triple narratives on which the project of global statehood has depended: the narratives of security, representation, and wealth and welfare. While individual cases of state failure and collapse may owe much to specific circumstances and the behaviour of particular individuals, they must also be understood within the context of a world in which maintaining states has become increasingly difficult. [source] | ||||||||||||||||||||||||||||||||||||||||||||||