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Selected AbstractsComparison of the firing patterns of human postganglionic sympathetic neurones and spinal , motoneurones during brief burstsEXPERIMENTAL PHYSIOLOGY, Issue 1 2004Vaughan G. Macefield Focal recordings from individual postganglionic sympathetic neurones in awake human subjects have revealed common firing properties. One of the most striking features is that they tend to fire only once per sympathetic burst. Why this should be so is not known, but we propose that the short duration of the burst may limit the number of times a sympathetic neurone can fire. Indeed, while the normal variation in cardiac interval and burst duration is too narrow to reveal a correlation between burst duration and the number of spikes generated, we know that spike generation is doubled when burst duration is doubled following ectopic heart beats. To test the hypothesis that the burst duration constrains the firing of individual sympathetic neurones to one per burst, we used the human skeletomotor system as a model for the sympathetic nervous system, which allowed us to vary burst duration and amplitude experimentally. Intramuscular recordings were made from 27 single motor units (, motoneurones) in the tibialis anterior or soleus muscles of seven subjects; multiunit EMG activity was recorded via surface electrodes and blood pressure was recorded continuously. Subjects were instructed to generate EMG bursts of varying amplitude in the intervals between heart beats. By constraining the firing of , motoneurones to brief (,400 ms) bursts we could emulate real sympathetic bursts. Individual motoneurones generated 0,7 spikes during the emulated sympathetic bursts, with firing patterns similar to those exhibited by real sympathetic neurones. Eleven motor units showed significant positive linear correlations between the number of spikes they generated within a burst and its amplitude, whereas for 17 motor units there were significant positive correlations between the number of spikes and burst duration. This indicates that burst duration is a major determinant of the number of times an , motoneurone will fire during a brief burst, and we suggest that the same principle may explain the firing pattern typical of human sympathetic neurones. [source] Constructal tree-shaped paths for conduction and convectionINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2003Adrian Bejan Abstract This lecture reviews a series of recent results based on the geometric minimization of the resistance to flow between one point (source, sink) and a volume or an area (an infinity of points). Optimization is achieved by varying the geometric features of the flow path subject to volume constraints. The method is outlined by using the problem of steady volume-point conduction. Optimized first is the smallest elemental volume, which is characterized by volumetric heat generation in a low-conductivity medium, and one-dimensional conduction through a high-conductivity ,channel'. Progressively larger volumes are covered by assemblies of previously optimized constructs. Tree-shaped flow structures spring out of this objective and constraints principle. Analogous problems of fluid flow, and combined heat and fluid flow (convection, trees of fins) are also discussed. The occurrence of similar tree structures in nature may be reasoned based on the same principle (constructal theory) (Bejan, 2000). Copyright © 2003 John Wiley & Sons, Ltd. [source] Law and the Image of a Nation: Religious Conflict and Religious Freedom in a Brazilian Criminal CaseLAW & SOCIAL INQUIRY, Issue 1 2001Eric W. Kramer This article examines a criminal trial in Brazil that touched on the imagined role of religion in public life. The case involved a Protestant minister accused of religious discrimination and of vilipending an image of Nossa Senhora Aparecida, the patron saint of Brazil. The prosecution argued and the court concurred that the minister's iconoclastic verbal and physical gestures endangered the constitutional guarantee of religious freedom. Yet the defense claimed that his actions, stemming from his religious convictions, expressed this same principle of freedom. Different visions of religious free-dom are at stake in the case as well as how such freedom relates to the rights and private lives of citizens. Placed in the history of church-state relations in Brazil, the case raises the problem of interpreting concepts of religious pluralism, religious freedom, and freedom of expression in Brazilian law. [source] Polymer Foams Stabilized by Particles Adsorbed at the Air/Polymer InterfaceMACROMOLECULAR RAPID COMMUNICATIONS, Issue 15 2008Prachi Thareja Abstract In aqueous systems, partially hydrophobic particles are known to stabilize foams even in the absence of any added surfactant. This paper shows that the same principle can be applied to polymeric systems: particles that are partially wetted by a polymer melt can stabilize a foam of that polymer. The foam stability is attributable to the adsorption of the particles at the air/polymer interface. Remarkably, stable foams are realized even from polymers that are liquid at room temperature, and hence are otherwise unfoamable. The implications of this result to practical foaming operations are discussed. [source] A Novel Device for Single Particle Light Scattering Size Analysis and Concentration Measurement at High Pressures and TemperaturesPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 2 2008Heinz Umhauer Abstract Based on the findings of previous work, a novel instrument was developed for the size analysis and concentration measurement of particles dispersed in gases at high temperatures (600,°C) and pressures (16 bar). The main motivation for the construction of this device was a measurement requirement at the conditions of a pressurized pulverized coal combustion (PPCC) test installation in Dorsten, Germany. The development of a high efficiency (>,50,%), coal based, combined cycle process, and specifically, the development of efficient gas cleaning technology for gas combustion under demanding conditions (1400,°C and 16 bar) was the main target. A suitable measurement technique was required for the determination of particle size and concentration downstream of the gas cleaning equipment, which is able to operate close to the given conditions. The performance of the novel device was tested in several measurement series with various monodisperse aerosols at ambient conditions as well as in high pressure, high temperature situations with very satisfactory results, i.e., the lower detection limit (50,% counting efficiency at ca. 0.3 ,m) and resolution of the novel device are comparable to state of the art instruments (of the same principle) intended for room temperature operation. [source] Assessing local residence time distributions in screw extruders through a new in-line measurement instrumentPOLYMER ENGINEERING & SCIENCE, Issue 4 2006Xian-Ming Zhang This work aimed at developing a new instrument to measure in real time the residence time distribution (RTD) in screw extruders. The instrument followed the same principle as the one reported in the literature but possessed several important advantages. For example, the detection system had two probes that allowed to simultaneously measure RTDs at any two different locations of an extruder, thus providing the possibility of calculating the local RTD between them by a deconvolution method based on a statistical theory for the RTD. Its performance was evaluated on a corotating twin-screw extruder using anthracene as tracer and polystyrene as flowing material. The effects of various process parameters such as feed rate and screw speed on the RTDs were investigated. The emphasis was placed, however, on the effect of the staggering angle of kneading discs on local RTDs both in the kneading zone itself and its neighboring upstream and downstream screw zones. This work is in support of an ongoing project on the simulation of flow in corotating twin-screw extruders. POLYM. ENG. SCI., 46:510,519, 2006. © 2006 Society of Plastics Engineers. [source] Development of a FTA versus Parts Count Method Model: Comparative FTAQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 5 2003G. Arcidiacono Abstract This study adopts a special Fault Tree Analysis (FTA) method called Comparative FTA to compare the reliability of an electronic braking system with its mechanical counterpart. To this end two Top Events, ,Ineffective parking braking' and ,Wheels jamming during emergency braking', were analysed. One of the limitations of classic FTA is that the setting up of the tree diagram requires the long-term involvement,one to two months according to Fiat Auto,of specialists of the system being studied. For this reason, therefore, when dealing with relatively complex systems, classic FTA is only used when safety is involved. This paper introduces a simplified FTA model based on the same principle as the Parts Count Method, which limits its attention to the new branches, thereby avoiding the study of all the branches of the tree, in order to make FTA management easier and to encourage its use. The probability that a Top Event takes place is therefore evaluated by studying the different causes which diversify the solutions considered. This approach is a lean practice to minimize the resources and the time of the analysis. It has guaranteed very satisfactory results and, therefore, Fiat Auto has introduced the practice in their Corporate Instructions. Copyright © 2003 John Wiley & Sons, Ltd. [source] Effects of a community intervention to reduce the serving of alcohol to intoxicated patronsADDICTION, Issue 6 2010Katariina Warpenius ABSTRACT Aims To assess the effects of an alcohol prevention programme to reduce the serving of alcoholic beverages to intoxicated clients on licensed premises. Research design A controlled pre- (2004) and post-intervention study (2006) design. Intervention A community-based programme combining law enforcement, responsible beverage service training, information campaigns and policy initiatives in one Finnish town (Jyväskylä). Participants and measurements A male actor pretended to be clearly under the influence of alcohol and tried to buy a pint of beer at licensed premises. For the baseline measurement, every bar and nightclub was visited in the intervention and the control areas (94 licensed premises in total). Post-intervention data were gathered with the same principles (100 licensed premises in total). A researcher observed every visit and documented the results. Results In the post-intervention study there was a statistically significant increase in refusals to serve denials alcohol to the actor in the intervention area (from 23% to 42% of the licensed premises) compared to refusals in the control area (from 36% to 27% of the licensed premises). Conclusion Previous research has documented that multi-component community-based interventions can have a significant impact on over-serving of alcohol when training and house policies are combined with effective law enforcement. The present findings also demonstrate that comprehensive Responsible Beverage Service (RBS) interventions applied at a local community level can be effective in decreasing service to intoxicated clients in a Nordic context. [source] Perceptual load interacts with stimulus processing across sensory modalitiesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2009J. Klemen Abstract According to perceptual load theory, processing of task-irrelevant stimuli is limited by the perceptual load of a parallel attended task if both the task and the irrelevant stimuli are presented to the same sensory modality. However, it remains a matter of debate whether the same principles apply to cross-sensory perceptual load and, more generally, what form cross-sensory attentional modulation in early perceptual areas takes in humans. Here we addressed these questions using functional magnetic resonance imaging. Participants undertook an auditory one-back working memory task of low or high perceptual load, while concurrently viewing task-irrelevant images at one of three object visibility levels. The processing of the visual and auditory stimuli was measured in the lateral occipital cortex (LOC) and auditory cortex (AC), respectively. Cross-sensory interference with sensory processing was observed in both the LOC and AC, in accordance with previous results of unisensory perceptual load studies. The present neuroimaging results therefore warrant the extension of perceptual load theory from a unisensory to a cross-sensory context: a validation of this cross-sensory interference effect through behavioural measures would consolidate the findings. [source] Last-century changes of alpine grassland water-use efficiency: a reconstruction through carbon isotope analysis of a time-series of Capra ibex hornsGLOBAL CHANGE BIOLOGY, Issue 4 2010INÊS C. R. BARBOSA Abstract The ecophysiological response of an alpine grassland to recent climate change and increasing atmospheric CO2 concentration was investigated with a new strategy to go back in time: using a time-series of Capra ibex horns as archives of the alpine grasslands' carbon isotope discrimination (13,). From the collection of the Natural History Museum of Bern, horns of 24 males from the population of the Augstmatthorn,Brienzer Rothorn mountains, Switzerland, were sampled covering the period from 1938 to 2006. Samples were taken from the beginning of each year-ring of the horns, representing the beginning of the horn growth period, the spring. The horns' carbon 13C content (,13C) declined together with that of atmospheric CO2 over the 69-year period, but 13, increased slightly (+0.4,), though significantly (P<0.05), over the observation period. Estimated intercellular CO2 concentration increased (+56 ,mol mol,1) less than the atmospheric CO2 concentration (+81 ,mol mol,1), so that intrinsic water-use efficiency increased by 17.8% during the 69-year period. However, the atmospheric evaporative demand at the site increased by approximately 0.1 kPa between 1955 and 2006, thus counteracting the improvement of intrinsic water-use efficiency. As a result, instantaneous water-use efficiency did not change. The observed changes in intrinsic water-use efficiency were in the same range as those of trees (as reported by others), indicating that leaf-level control of water-use efficiency of grassland and forests followed the same principles. This is the first reconstruction of the water-use efficiency response of a natural grassland ecosystem to last century CO2 and climatic changes. The results indicate that the alpine grassland community has responded to climate change by improving the physiological control of carbon gain to water loss, following the increases in atmospheric CO2 and evaporative demand. But, effective leaf-level water-use efficiency has remained unchanged. [source] Towards a phylogenetic classification of dendrocoelid freshwater planarians (Platyhelminthes): a morphological and eclectic approachJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 4 2006R. Sluys Abstract We explore and review the taxonomic distribution of morphological features that may be used as supporting apomorphies for the monophyletic status of various taxa in future, more comprehensive phylogenetic analyses of the dendrocoelid freshwater planarians and their close relatives. Characters examined are: (i) musculature of the pharynx; (ii) anatomy of the eye; (iii) distribution of testis follicles along the longitudinal axis of the body; (iv) epidermis of the body wall; (v) musculature of the ventral body wall; (vi) presence or absence of a penis papilla; (vii) position of the mouth opening; and (viii) anterior adhesive organ. A phylogenetic hypothesis, in the form of a character state tree, is developed. This hypothesis suggests that the Kenkiidae should be resurrected as a separate family, sharing a sistergroup relationship with the Dendrocoelidae. This sistergroup relationship is supported by the shared presence of an apomorphic anterior adhesive organ. Although the shape of the anterior adhesive organ, both within and between kenkiids and dendrocoelids, may differ considerably between species, they are all constructed according to the same principles. The monophyly of the Kenkiidae is supported by the presence of an apomorphic thickening of the marginal zone of the epidermis and presumably also by the presence of prepharyngeal testes. Within the Kenkiidae, the genus Macrocotyla should be considered as a junior synonym of Kenkia, which is characterized by the presence of an apomorphic ,planariid pharynx-type 2'. The monophyly of the Dendrocoelidae is suggested by the presence of a dendrocoelid type of pharynx. It is shown that multicellular eye cups with numerous photoreceptor cells are not restricted to the Dugesiidae and the Terricola but are also characteristic for the Dendrocoelidae; the phylogenetic implications of this character state distribution are discussed. It is pointed out that in planarians there may be a relationship between: (i) body size, the size of an eye cup and the number of its constituent pigment cells; and (ii) the size of an eye cup and the number of photoreceptor cells that it contains. Some tentative phylogenetic groups are suggested on the basis of the following presumed apomorphic characters: presence of transverse fibres in the ventral subepidermal musculature, presence of an extra longitudinal muscle layer in the outer pharynx musculature, a mouth opening that has shifted anteriad. It is suggested that the presumed monophyly of the genus Bdellocephala is supported by the apomorphic absence of a penis papilla, combined with a penial lumen provided with many plicae. Zusammenfassung Wir untersuchen und begutachten die taxonomische Verbreitung morphologischer Merkmale, die man als Apomorphien für die Monophylie verschiedener Taxa in einer zukünftigen umfangreicheren phylogenetischen Analyse der Dendrocoeliden und ihrer nächsten Verwandten heranziehen könnte. Zu diesen untersuchten Merkmalen gehören die Pharynxmuskulatur, die Augen-Anatomie, die Anordnung der Hodenfollikel entlang der Längsachse des Körpers, die Epidermis, die Muskulatur der ventralen Körperwand, das Vorhandensein oder Fehlen einer Penispapille, die Lage der Mundöffnung sowie des vorderen Hartorgans. Eine phylogenetische Hypothese wurde als character state-Stammbaum entwickelt. Hierin wird vorgeschlagen, die Kenkiidae wieder als eigenständige Familie und als Schwestergruppe der Dendrocoelidae zu betrachten. Dieses Schwestergruppen-Verhältnis wird durch den gemeinsamen Besitz eines apomorphen vorderen Haftorgans gestützt. Obwohl sich die Form dieses Organs sowohl innerhalb als auch zwischen Kenkiiden und Dendrocoeliden beträchtlich zwischen den Arten unterscheiden kann, ist es grundsätzlich gleich aufgebaut. Die Monophylie der Kenkiidae wird durch eine als apomorph betrachtete Verdickung des Epidermisrandes und durch das Auftreten praepharyngealer Hoden gestützt. Innerhalb der Kenkiidae sollte die Gattung Macrocotyla als Juniorsynonym von Kenkia angesehen werden, die durch den apomorphen Planarien-Pharynx-Typ 2 charakterisiert ist. Als Beleg für die Monophylie der Dendrocoelidae wird der Dendrocoeliden-Pharynx-Typ vorgeschlagen. Es wird gezeigt, dass vielzellige Augenbecher mit zahlreichen Photorezeptorzellen nicht auf die Dugesiidae und die Terricola beschränkt, sondern auch für die Dendrocoelidae charakteristisch sind; die phylogenetische Bedeutung dieser Merkmalsverteilung wird diskutiert. Es wird hervorgehoben, dass es in den Planarien wahrscheinlich eine Beziehung zwischen (i) Körpergröße, Größe der Augenbecher und Zahl der Photorezeptorzellen ebenso wie (ii) der Größe eines Augenbechers und der Zahl seiner Photorezeptorzellen gibt. Versuchsweise werden einige phylogenetische Gruppierungen auf der Basis der folgenden vermutlich apomorphen Merkmale vorgeschlagen: Vorhandensein transversaler Fasern in der ventralen subepidermalen Muskulatur, Auftreten einer zusätzlichen Längsmuskelschicht in der äußeren Pharynxmuskulatur und eine nach vorn verschobene Mundöffnung. Es wird weiterhin vorgeschlagen, die vermutete Monophylie der Gattung Bdellocephala durch das Fehlen einer Penispapille als Autapomorphie zu stützen, zusammen mit dem Merkmal eines durch viele Falten gekennzeichneten Penislumens. [source] The three-dimensional power spectrum of dark and luminous matter from the VIRMOS-DESCART cosmic shear surveyMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2003Ue-Li Pen ABSTRACT We present the first optimal power spectrum estimation and three-dimensional deprojections for the dark and luminous matter and their cross-correlations. The results are obtained using a new optimal fast estimator, deprojected using minimum variance and Singular Value Decomposition (SVD) techniques. We show the resulting 3D power spectra for dark matter and galaxies, and their covariance for the VIRMOS-DESCART weak lensing shear and galaxy data. The survey is most sensitive to non-linear scales kNL, 1 h Mpc,1. On these scales, our 3D power spectrum of dark matter is in good agreement with the RCS 3D power spectrum found by Tegmark & Zaldarriaga. Our galaxy power is similar to that found by the 2MASS survey, and larger than that of SDSS, APM and RCS, consistent with the expected difference in galaxy population. We find an average bias b= 1.24 ± 0.18 for the I -selected galaxies, and a cross-correlation coefficient r= 0.75 ± 0.23. Together with the power spectra, these results optimally encode the entire two point information about dark matter and galaxies, including galaxy,galaxy lensing. We address some of the implications regarding galaxy haloes and mass-to-light ratios. The best-fitting ,halo' parameter h,r/b= 0.57 ± 0.16, suggesting that dynamical masses estimated using galaxies systematically underestimate total mass. Ongoing surveys, such as the Canada,France,Hawaii Telescope Legacy Survey, will significantly improve on the dynamic range, and future photometric redshift catalogues will allow tomography along the same principles. [source] Our Chief Magistrate and His Powers: A Reconsideration of William Howard Taft's "Whig" Theory of Presidential LeadershipPRESIDENTIAL STUDIES QUARTERLY, Issue 2 2003MICHAEL J. KORZI This article discusses William Howard Taft's theory of presidential leadership. Often seen as embodying a passive or weak conception of the presidency and dismissed as anachronistic, the author argues that Taft's theory merits a second look. First, through analysis of Taft's presidential actions and academic writings, the author shows that his theory is far more nuanced and substantial than traditional accounts allow. Taft's theory is best characterized as a "party agency" Whig theory of the presidency because of its simultaneous concern with popular democracy (via political parties) and presidential moderation. Second, the author argues that Taft's theory of the presidency is rooted in nineteenth-century Whig and Republican ideas of presidential leadership, which, appropriately understood, embody most of the same principles and values. Thus was Taft in many ways a conservator of a nineteenth-century notion of presidential leadership. Finally, the author concludes that Taft's Whiggish theory of the presidency (as well as the nineteenth-century Whig/Republican theory of the presidency) has much to contribute to contemporary debates on presidential leadership. [source] Who Owns the Product?THE PHILOSOPHICAL QUARTERLY, Issue 217 2004Daniel Attas If persons fully own themselves and can acquire, by unilateral acts, unconditional full property rights to previously unowned natural resources, then by these same principles of property they also own the products of their property and of their labour. But (a) the principles of property are silent on the question of the division of joint products; (b) the market is a form of cooperation in production which makes the total social product a joint product. In the circumstances of an unrestrained fully developed market, therefore, it is not fully determinate what one's product is. Thus the holdings that each person ends up with cannot be justified merely in terms of ownership of products. I offer an explanation of why some may resist this view of the market. [source] THE DATING OF ANCIENT CHINESE CELADON BY INAA AND PATTERN RECOGNITION METHODS,ARCHAEOMETRY, Issue 4 2009GUOXI XIE In 2005, sherds of a special type of ancient Longquan celadon ware were excavated at Maojiawan, in the city of Beijing, China. Although archaeologists agree that these sherds were fired in the period between the Yuan and Ming Dynasties, their specific date is unclear. In order to solve this problem, five other groups of ancient Longquan celadon sherds of known date were selected as reference samples. The elemental body composition of all the sherds was determined by Instrumental Neutron Activation Analysis (INAA). Using the same principles as in provenance research, pattern recognition methods were used to build classification functions to specify the date of the unknown sherds. After analysing the experimental data by discriminant analysis, three classification functions were built. All the unknown sherds were classified as Ming Dynasty. This prediction is well in accordance with the fact that these sherds are similar to other Longquan Ming celadon, and so they should be fired in the same dynasty. This also verified the judgement of the Beijing Institute of Cultural Relics. [source] Translational Mini-Review Series on Vaccines: The Edward Jenner Museum and the history of vaccinationCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2007A. J. Morgan Summary Edward Jenner's discovery of vaccination must rank as one of the most important medical advances of all time and is a prominent example of the power of rational enquiry being brought to bear during the Age of Enlightenment in 18th century Europe. In the modern era many millions of lives are saved each year by vaccines that work essentially on the same principles that were established by Edward Jenner more than 200 years ago. His country home in Berkeley, Gloucestershire, is where he carried out his work and where he spent most of his life. The building is now a museum in which the life and times of Jenner are commemorated including not only the discovery of smallpox vaccination but also his other important scientific contributions to natural history and medicine. The trustees of the Edward Jenner museum are committed to promoting the museum as a real and "virtual" educational centre that is both entertaining and informative. [source] | ||||||||||||||||||||||