bluuebunny/crossref_metadata_2025 huggingface dataset:
Refutation and Relativism in Theaetetus 161-171
Authors: Long Alex
Published: April 2004

In this paper I discuss the dialogues between 'Protagoras', Theodorus and Socrates in Theaetetus 161-171 and emphasise the importance for this passage of a dilemma which refutation is shown to pose for relativism at 161e-162a. I argue that the two speeches delivered on Protagoras' behalf contain material that is deeply Socratic and suggest that this feature of the speeches should be interpreted as part of Plato's philosophical case against relativism, reflecting the relativist's own inability to defend his theory from attempts to refute it. I then discuss Theodorus' role in the refutation of Protagoras and argue that his voice is needed to get relativism disproved in the self-refutation argument of 171a-c. I conclude with a brief discussion of the image of Protagoras at 171d.
Knowing Freedom: Epicurean Philosophy Beyond Atomism and the Swerve
Authors: Baltzly Dirk , Wendlandt Lisa
Published: April 2004

This paper argues that Epicurus held a non-reductionist view of mental states that is in the spirit of Davidson's anomalous monism.1 We argue for this conclusion by considering the role that normative descriptions play in the peritropē argument from On Nature 25. However, we also argue that Epicurus was an indeterminist. We can know that atoms swerve because we can know that we make choices that are up to us and this is incompatible with the ancestral causal determination of mental states by atomic processes. Epicurus escapes the traditional criticism of indeterminist libertarians because the swerve is not meant to explain how choices may be free. The anti-reductionist stance on the mental means that nothing about atomic processes could possibly explain any particular mental event. Moreover, because of the practical and therapeutic nature of Epicurean philosophy, it is not necessary that Epicurus provide an explanation of how the swerve subserves freedom of choice. We know all that we need to know for eudaimonia when we know that some choices are up to us.
I. The Geopolitics of Power Projection in US Foreign Policy: From Colonization to Globalization
Authors: Houweling Henk , Amineh Mehdi Parvizi
Published: April 2004

This Chapter studies continuity and innovation in the geopolitics of America in projecting power beyond legally recognized borders. Exporting cultural symbols expressing what America has on offer plays as crucial a role in the opening of societies beyond borders as commodity exports and the activities of the CIA and the US Air Force do. The historical part summarizes early experience and aims at uncovering continuity in the foreign policy of getting America offshore. The hypothesis is that the US objective of inserting power and influence in West and CEA is to deny to a single state, other than the US itself, or coalition of powers not including the US, the capability to set conditions for accessing the energy resources of West and CEA. Our argument is that such a dominating coalition of actors not including the US, would arise from the creation of overland energy and other transportation links among the industries of Western Europe, Russia, Turkey, Northeast Asia, and China, leading to economic unification of Eurasia. Economic unification by creating overland energy and transport links of much of Eurasia would deprive the US navy of its power to interdict supplies of oil and food to core industrial areas of Eurasia and Japan. The reassertion of Russian power in the Caucasus and Central Asia should therefore be prevented. The EU and Japan should be prevented from developing autonomous military power and be kept dependent on maritime transported energy and food supplies. China should not host pipelines connecting energy resources of West Asia and CEA with the industries of Japan and Korea, whose unification and economic and strategic merger with China should be prevented. Iraq, Iran, and the Saudi Kingdom should be reformed into powers friendly of the US. Energy unification by overland transport systems, leading to economic unification between industries of these entities, would give major powers of the Asian landmass the potential for setting conditions for the US state and non-state actors to access the resources on the largest of world's islands. Such a power shift between the world's continents would reduce the Western Hemisphere to a rather dependent offshore island between the Atlantic and Pacific Oceans.
IX. Paradigms of Iranian Policy in Central Eurasia and Beyond
Authors: Rakel Eva
Published: April 2004

Iran and CEA have historically close links going back as far as the sixth century BC when the Persian Achaemenid Empire conquered the region. For a long time, Persian was the main language of the elite in CEA. Since the disintegration of the USSR, Iran has been determined to re-strengthen its position in CEA, particularly in economic and security terms. Iran is an active player in the Economic Co-operation Organization (ECO). It also promotes the construction of southern pipelines from CEA to export the region's oil and gas resources as it hopes to profit from it for its own oil and gas export. However, it has to be noted that Iran in no way is a dominant player in the region. The rivalry between the various political factions of the Iranian political elite - the Conservative Traditional Right (Rast-e Sonati), Traditionalist left (Chap-e Sonati), Revolutionary or New Left or Hizbollah, Conservative Modern Right Rast-e Modern - leads to incoherence in Iran's foreign policy and makes Iran an unreliable actor to cooperate with not only the countries of CEA but also for other countries interested in the region (i.e., the United States, European Union, Turkey, Russia, China, Saudi Arabia). Additionally, the great national economic problems in Iran are an obstacle for Iran to become more active economically in CEA.
X. Growing Tension and the Threat of War in the Southern Caspian Sea: The Unsettled Division Dispute and Regional Rivalry
Authors: Peimani Hooman
Published: April 2004

The absence of an acceptable legal regime for the division of the Caspian Sea among its five littoral states has created grounds for conflicts, crises, and wars in the Caspian region, a situation worsened since 2001 when Iran, Azerbaijan, and Turkmenistan found each other on a collision course over the ownership of certain offshore oilfields. The region has since been heading towards militarization, while the persistence of conflicts over the Caspian Sea's division has prepared the ground for military conflicts. Fear of lagging behind in an arms and the manipulation of conflicts by the United States and Turkey have further encouraged militarization. Against this background, certain factors, including Turkey's efforts to deny Iran political and economic gains in the Caspian region, the growing American military presence in Eurasia, and the expanding American-Azeri military ties since 11 September 2001 will likely contribute to the creation of a suitable ground for a military conflict in the Caspian region.
XI. The 'Power of Water' in a Divided Central Asia
Authors: Spoor Max , Krutov Anatoly
Published: April 2004

In the not-too-distant future, the former Soviet Central Asia could be confronted with resource-based conflicts or even, as some observers have suggested, with a "water war." Water is the scarce commodity in a region that is rich in oil, gas, and mineral resources. Most of the water comes from two rivers, the Syr Darya and the Amu Darya. These feed the Aral Sea, previously the fourth largest inland fresh (actually brackish) water reservoir in the world. These rivers and their tributaries, together, form the Aral Sea basin. Since the 1960s, the Aral Sea has shrunk rapidly in surface area and in volume of water, representing "one of the world's worst ecological disasters." Increased demand for water for irrigation and hydroelectric power by the competing newly independent states, both upstream and downstream, is a potential source of interstate and even interethnic conflict. The latter could occur in the densely populated Ferghana Valley, where various countries such as Kyrgyzstan, Tajikistan, and Uzbekistan share common borders.
XIII. International Challenges and Domestic Preferences in the Post-Soviet Political Transition of Azerbaijan
Authors: Ergun Ayça
Published: April 2004

In the post-Soviet transition, the role of the international element (i.e., external actors-foreign countries and international governmental and non-governmental organizations) is one important aspect of the study of state-society relations. The international element highlights the fact that post-Soviet transition is not a question of internal politics only and is affected by redefinition of the relationships with the outside world. Thus, the interplay between international and domestic actors should not be ignored in conceptualizing the process of transition, but similarly it should not be used as a single tool to explain the process but rather as a complementary factor that aids in our understanding of its path. This article puts the post-Soviet political transformation in Azerbaijan into the context of both the regional and the global framework, exploring the interaction between the international element and domestic actors. The first part focuses on Azerbaijan's relations with Armenia, Iran, Russia, Turkey, and the West and explores the question of how Azerbaijan's perceptions about its external environment, with reference to these countries, can contribute or hinder political transformation. The second part of the article examines the degree of impact and promoting effect of the international element on political transformation, while focusing on the relationship between international organizations, the state, and the societal actors.
New pressure-based methods for quantifying radiator airflow
Authors: Ng E Y , Watkins S , Johnson P W
Published: April 2004

The high complexity of vehicle front-end design, arising from considerations of aerodynamics, safety and styling, causes the airflow velocity profile at the radiator face to be highly distorted, leading to potentially reduced airflow volume for heat dissipation. A review of the existing experimental techniques for quantifying radiator airflow indicates that currently the most commonly used methods in the automotive industry are propeller based, despite the fact that the accuracy is in doubt, especially when documenting detailed airflow distributions. Two relatively new techniques, including a four-hole dynamic pressure (Cobra) probe and a new pressure-based technique, are presented in this paper. The Cobra probe featured a head size of 1.2 mm and was used to document flow fields in proximity to a section of radiator core in a wind tunnel. The results show that the flow field at the radiator core exit was extremely complex, consisting of jets and wakes. In an investigation of the effect of airflow maldistribution on radiator heat-transfer performance, a newly developed pressure-based technique was implemented for the measurement of radiator airflow distribution. This technique, based on relating local airflow pressure drop through the radiator core to local velocity, is also discussed in the paper. The advantages of the technique over the existing methods include simplicity, robustness and relative insensitivity to air temperature thus making the technique suitable for use in complex, thermally stratified flow fields.
Assessing dynamic tyre forces occurring after traversing local roadway irregularities by the pothole dynamic amplification factor method
Authors: Pesterev A V , Bergman L A , Tan C A
Published: April 2004

A technique to assess the dynamic tyre forces arising after passing road surface irregularities by a vehicle modelled as a general linear multiple-degrees-of-freedom system is presented. The equations governing vibration of a vehicle moving along an uneven profile are, first, transformed to the state-space form and, then, to a system of uncoupled first-order complex differential equations. For a local roadway irregularity described functionally, solutions of all equations are found analytically and expressed in terms of a unique function of one complex variable, the so-called pothole dynamic amplification factor (DAF). The problem is shown to be decomposed into separate calculating vehicle- specific data, which are easily constructed in terms of physical and modal vehicle characteristics, and the DAF function, which does not depend on the vehicle model. The dynamic tyre forces are obtained then by simple arithmetic manipulation of the complex numbers obtained. The technique discussed is not specific to a particular vehicle model or an irregularity shape. The discussion is amply illustrated by examples of the application of the technique to the calculation of the tyre forces for three simple vehicle models.
An exhaust pressure control strategy for a diesel engine
Authors: Wijetunge R S , Hawley J G , Vaughan N D
Published: April 2004

A control method has been developed that uses exhaust manifold pressure measurements to regulate the turbine nozzle vane position on a turbocharged diesel engine with variable-geometry turbocharger during transient operation. Significant reductions in exhaust manifold pressures are achieved without degrading the turbocharger response and, overall, engine behaviour is improved through more rapid torque delivery, lower transient smoke and improved aircharge stability immediately after the transient.
Treatment of erectile dysfunction
Authors: Dinsmore Wallace
Published: April 2004

Erectile dysfunction (ED) is an inability to attain or maintain an erection sufficient for satisfactory sexual intercourse. It is an undertreated and underdiagnosed condition that can be due to vasculogenic, neurogenic, hormonal and psychogenic factors. Effective treatment of ED should restore quality of life and allow patients to return to the sex life they had before. Current therapeutic options include non-pharmacological treatments, locally administered drugs and oral therapies. The oral phosphodiesterase-5 (PDE5) inhibitors are considered first-line treatments of ED and have revolutionized ED management in the last five years. Three PDE5 inhibitors are currently available, sildenafil, vardenafil and tadalafil. They are all effective with similar efficacy and good safety profiles. However, tadalafil has the added benefit of a broad window opportunity offering patients more freedom to choose when to initiate sexual activity.
Fatal lactic acidosis associated with highly active antiretroviral therapy in patients with advanced human immunodeficiency virus infection in Taiwan
Authors: Sheng W H , Hsieh S M , Lee S C , Chen M Y , Wang J T , Hung C C , Chang S C
Published: April 2004

Lactic acidosis (LA), a rare but life-threatening adverse effect associated with antiretroviral therapy, has been reported with an increasing frequency since the mid1990s. From June 1994 to June 2002, a total of six patients, four males and two females with a median age of 43 years (range, 30 to 74 years), had been diagnosed with LA. The estimated incidence of LA was 5.1 per 1000 patient-years (PYs) on highly active antiretroviral therapy (HAART) (95% confidence interval [95% CI], 4.5-5.5 per 1000 PYs) and 4.4 per 1000 PY on nucleoside analogues (NAs) (95% CI, 3.9-4.7 per 1000 PYs). Their median body mass index at diagnosis of LA was 17.6 kg/m2 (range 16.3 to 22.6 kg/m2). The median CD4+ lymphocyte count at the initial diagnosis of HIV infection and at the onset of LA was 38 cells/µL (range, 4 to 103 cells/µL) and 108 cells/µL (range, 79 to 224 cells/µL), respectively. The most common symptoms were nausea, vomiting, and dyspnoea. All of the patients had findings suggestive of NA-related mitochondrial toxicity, such as myositis, pancreatitis, fatty hepatitis, peripheral neuropathy or lipodystrophy. The prescribed NA related to LA were stavudine in six patients, lamivudine, five, and didanosine, one. Despite treatment, all patients died of persistent circulatory collapse following LA. The median duration from diagnosis to death was eight days (range, 4-17 days). Our report highlights that clinicians caring for patients with AIDS should be alerted to the potentially fatal LA associated with antiretroviral therapy when patients present with low body mass index, lipodystrophy, unexplained abdominal symptoms, dyspnoea, or elevated aminotransferases.
Risking Basin Analysis Results III. Effects of Uncertain Geochemical Parameters on Hydrocarbon Generation
Authors: Lerche I.
Published: April 2004

This paper considers the effect of uncertainty in geochemical kinetic parameters on the production of oil and gas from kerogen in a basin. Three kerogen types are considered with different fractional breakdowns to oil and gas. The illustration uses three kinetic parameters for each of the kerogen types so that in total one has available 12 parameters. Allowing only the kinetic parameters associated with the kinetic breakdown to vary by up to ±50% around nominal values, one can determine under what conditions it is necessary to be concerned about refining better the uncertain parameters and also one can determine which parameters need to first be sharpened in order to improve resolution on the hydrocarbon generation. The argument presented here can be applied to any proposed kinetic scheme for converting kerogen to oil and gas. The example presented shows that the broad range of times and depths that will produce hydrocarbons are such that changes in the kinetic parameters, even by the large factor of 50%, produce less than about a 10% uncertainty in the total amount of oil and gas generated so that there is little need to try to narrow the wide dynamic range of the geochemical kinetic parameters. This insensitivity of hydrocarbon generation to precise values for the kinetics has been seen before in isolated case studies, but the use of a fast Excel basin analysis code together with the risking code Crystal Ball, strengthens the argument to a very wide swath of conditions – something that was not easy to do before the high speed Excel basin analysis code was available.
Production from Multiple Horizons: Costs, Return on Investment and Chances of Multiple Success
Authors: Lerche I.
Published: April 2004

The purpose of this paper is to show how one can assess the worth of undertaking the drilling of an horizon in an already producing oil field based upon information already available from prior drilled horizons in the same field. The device we use to illustrate one way to assess this worth is the return on investment ratio (ROI) for each and every horizon when costs are to be shared between horizons. Other measures of worth are also available, such as accumulated gains versus accumulated costs. The advantage of the ROI is that it enables a corporation to determine quickly what the effective worth is of each horizon in relation to fractions of the total costs assigned to each formation, and also helps with tax discussions when each horizon is viewed as an individual entity for tax purposes, or when a corporation is interested in farming-out some, but not all, of the producing horizons to raise capital for further exploration and/or development needs.
Technical Issues for Wind Energy Integration in Power Systems: Projections in Italy
Authors: Pantaleo A. , Pellerano A. , Trovato M.
Published: April 2004

This paper is review of the main technical issues of wind energy integration in power systems. After summarizing the main factors affecting this integration and reviewing the analytical studies that have been carried out, the perspectives for growth in Italy are investigated. The wind power penetration projections for Italy show that the installed wind capacity should be in the range of 3,000 – 5,000 MW by 2010, with a wind power penetration level of 4.5 to 7% of peak demand. Even if, at a global level, no substantial problems in power system operation are expected, the high concentration of the Italian wind energy resource in a few areas in Southern Italy, Sicily and Sardinia Regions, can cause grid integration difficulties. In fact, new transmission networks should be built to connect this dispersed energy source to the power system. Moreover, the large wind penetration expected in isolated areas, such as in Sardinia Island, can cause load-following and regulation problems, especially during low-load periods and morning ramp-up or evening drop-off hours. These issues should be taken into account to avoid the risk of wind generation curtailments.
The Energy Yield of Roof Mounted Wind Turbines
Authors: Mertens S.
Published: April 2004

The roof is a possible site for small wind turbines. This is a new but more and more accepted idea. Several Dutch companies in close cooperation with the Section Wind Energy of Delft University of Technology are busy with the design of small roof wind turbines at the moment. The important flow features for a wind turbine on the roof however are unknown. The common wind engineering knowledge is only focussed on extreme wind speeds in order to have a safe building. So, models to calculate the flow features on the roof, important for a wind turbine, have to be developed. This paper gives a first attempt to describe the flow features and guidelines necessary for siting of small wind turbines on the roof. They concern: the desirable height above the roof, the change of the undisturbed wind to the wind speed above the roof and the probability distribution of the wind speed above the roof. With use of the guidelines three example calculations are given to assist the reader in the calculation procedure.
Variable-Speed Wind Turbines with Doubly-Fed Induction Generators Part IV: Uninterrupted Operation Features at Grid Faults with Converter Control Coordination
Authors: Akhmatov Vladislav
Published: April 2004

A model of variable-speed wind turbines equipped with doubly-fed induction generators (DFIG) and controlled by partial-load frequency converters described in [1,2] is applied in power stability investigations. A technical feature of uninterrupted operation at grid disturbances of large wind farms with such variable-speed wind turbines is suggested and discussed. This technical feature is based on fast re-start of the rotor converter, which blocks at grid faults. The main reactive power control is organised by the rotor converter [3]. The new part is that reactive power is controlled by the grid-side converter when the rotor converter blocks. Possible discrepancies between the results reached with the detailed representation of the frequency converter and the representation where only the rotor converter is regarded are notified and explained. The converter representation details influence on the machine current transients modelled at grid disturbances and also on damping characteristics of torsional shaft oscillations.
Using Historical Climate Data to Evaluate Climate Trends: Issues of Statistical Inference
Authors: Loehle Craig
Published: April 2004

A strong case for global warming has been made based on reconstructed global climate histories. However, certain unique features of paleoclimate data make statistical inference problematic. Historical climate data have dating error of such a magnitude that combined series will really represent very long-term averages, which will flatten peaks in the reconstructed series. Similarly, dating error will prevent peaks (e.g., of the Medieval Warm Period) from multiple series from lining up precisely. Meta-analysis is proposed as a tool for dealing with dating uncertainty. While it is generally assumed that a proper null model for twentieth-century climate is no trend, it is shown that the proper prior expectation based on past climate is that climate trends over a century period are likely. Climate data must be detrended before analysis to take this prior expectation into account.
Economic Theory and the Failure of Electricty Deregulation in Sweden
Authors: Banks Ferdinand E.
Published: April 2004

The deregulation of electricity has failed in Sweden. Since the beginning of the deregulation ‘experiment’, the trend price of electricity has increased much faster than the consumer price index, especially during recent years. More importantly, because of (1) the lack of investment in domestic generating (and perhaps transmission) facilities by Swedish power companies, (2) the questionable strategy employed by these firms to manage hydroelectric reserves, (3) increased and to some extent irrational energy taxes, and (4) the beginning of nuclear ‘disengagement’, households and businesses are vulnerable to a prolonged ‘spike’ in electricity prices. Everything considered, the recent history of the Swedish electricity sector – and particularly that of the overpraised Nordic Electric Exchange (i.e. Nord Pool) – should be considered a wake-up call instead of an example.
The Mechanics of E.P.: The Dispersion of a Jet Discharging into a Wavy Stream
Authors: Abdel-Rahman Adel A.
Published: April 2004

The present experimental results provide basic information in the mechanics of environmental pollution in a wave environment. They may contribute to the development of waste control, particularly in oil-related industries, power plants and desalination units. Man-induced waves could be one appropriate solution for reducing the concentration (temperature) of the discharaged waste from these industries. The turbulence characteristics of an experimental study is described in which the discharge of a water jet in a wavy channel crossflow is compared to an identical discharge in a uniform crossflow. The comparison highlights the additional wave-induced mixing and shows that the wave has a significant effect on the turbulent fluctuating velocity field. Four different values of Jet-to-crossflow velocity ratio are examined in the present study. Raw data is obtained using LDA system, and reported results include contour plots and transverse profiles of the mean velocity, fluctuation intensity, skewness factor and flatness factor. Power spectral of the velocity fluctuation is also reported.
Slippery Business Why America Attacked Iraq
Authors: Kane Tom , Einstein Albert
Published: April 2004

It is argued that American leaders and their British counterparts responded to the situation in Iraq as a broad foreign policy problem, not as a simple opportunity to seize oilfields. Nevertheless, the future of the global oil supply undoubtedly looms large in their policy considerations. The importance of petroleum to modern society requires little elaboration, and although experts disagree about how much remains available for extraction, the amount is finite. Demand, meanwhile, continues to increase, particularly in countries with emerging industrial economies and growing populations. US planners are undoubtedly susceptible to self-interest, but events challenge the argument that they are committed to a grand scheme to bring Iraq's oil under direct American control.
Some Analytic Results for the Study of Broadband Noise Radiation from Wings, Propellers and Jets in Uniform Motion
Authors: Farassat F. , Casper J.
Published: April 2004

Alan Powell has made significant contributions to the understanding of many aeroacoustic problems, in particular, the problems of broadband noise from jets and boundary layers. In this paper, some analytic results are presented for the calculation of the correlation function of the broadband noise radiated from a wing, a propeller, and a jet in uniform forward motion. It is shown that, when the observer (or microphone) motion is suitably chosen, the geometric terms of the radiation formula become time independent. The time independence of these terms leads to a significant simplification of the statistical analysis of the radiated noise, even when the near field terms are included. For a wing in forward motion, if the observer is in the moving reference frame, then the correlation function of the near and far field noise can be related to a space-time cross-correlation function of the pressure on the wing surface. A similar result holds for a propeller in forward flight if the observer is in a reference frame that is attached to the propeller and rotates at the shaft speed. For a jet in motion, it is shown that the correlation function of the radiated noise can be related to the space-time cross-correlation of the Lighthill stress tensor in the jet. Exact analytical results are derived for all three cases. For the cases under present consideration, the inclusion of the near field terms does not introduce additional complexity, as compared to existing formulations that are limited to the far field.
Wall-Cavity Acoustic Green's Function at Low Mach Number
Authors: Howe M. S.
Published: April 2004

Analytical approximations are developed for the low Mach number, aeroacoustic Green's function for a rectangular or circular cylindrical open cavity in a plane, rigid wall. The formulae can be used to predict the sound radiated into the main flow from a knowledge of the hydrodynamic flow near the cavity. At low Mach numbers the sound is a small by-product of the main flow, whose hydrodynamic properties can first be determined from observation or from a numerical treatment of the incompressible Navier-Stokes equations. Detailed predictions are made of the lowest order, open cavity resonance frequencies, and it is shown how a resonance is excited by the unsteady drag, and also by the lift or drag force experienced by a small bluff body placed in the flow close to the cavity. The cavity resonance frequencies are complex, with imaginary parts depending primarily on radiation damping, which can be sufficiently large for a shallow, open cavity, that a distinct resonance peak is absent from the acoustic spectrum – for a square cavity such peaks are predicted only when the cavity depth exceeds about half the cavity length. For very shallow cavities the efficiency of sound production by volumetric pulsations within the cavity is comparable to that of free field turbulence quadrupoles, and therefore negligible at low Mach numbers.
Designing Clean Jet-Noise Facilities and Making Accurate Jet-Noise Measurements
Authors: Ahuja K. K.
Published: April 2004

The main objective of this paper is to provide guidelines for designing and calibrating a high quality, static, jet-noise research facility and making high-quality jet noise measurements. Particular emphasis is placed on methodology for determining if internal noise is dominant in the jet noise spectrum. A section of this document is devoted to clarifying the terminology associated with microphone frequency response corrections and providing a step-wise description of other corrections that must be applied to the measured raw spectra before the jet noise data can be considered accurate and ready for use for extrapolation to full-scale jet engine noise.
Optimierung mit Genetischen Algorithmen und eine Anwendung zur Modellreduktion (Optimization with Genetic Algorithms and an Application for Model Reduction)
Authors: Buttelmann Maik , Lohmann Boris
Published: April 2004

Genetische Algorithmen sind unter gewissen Voraussetzungen in der Lage, auch komplexe Optimierungsprobleme zu behandeln und aus einer sehr großen Zahl von möglichen Lösungen die beste oder zumindest sehr gute im Sinne eines Gütemaßes zu ermitteln. Nach dem Vorbild natürlicher Auslese und Fortpflanzung werden dabei Lösungskandidaten hoher Güte bevorzugt zur Erzeugung neuer Kandidaten verwendet, in der Erwartung, schrittweise zu noch besseren Lösungen zu gelangen. Der Beitrag gibt eine Einführung in die Grundlagen Genetischer Algorithmen und illustriert eine ingenieurtechnische Anwendung bei der Reduktion und Strukturfindung nichtlinearer Systemmodelle.
Diagnose zeitbewerteter ereignisdiskreter Systeme (Diagnosis of Timed Discrete Event Systems)
Authors: Schullerus Gernot , Supavatanakul Peerasan , Krebs Volker , Lunze Jan
Published: April 2004

Dieser Beitrag befasst sich mit der Diagnose von Prozessen, die als zeitbewertete ereignisdiskrete Systeme modelliert werden. Für die Diagnose dieser Systeme werden zwei Verfahren vorgestellt, die auf zeitbewerteten Synchronisationsgrafen bzw. auf zeitbewerteten Automaten beruhen. Beide Verfahren erkennen und lokalisieren Fehler durch Auswertung der Ereignisfolge und der gemessenen Ereigniszeitpunkte.
Ein prädiktives, sich an Fahrzeugumfelddaten anpassendes Gangwechselsystem für Kfz (A Predictive Gear Shift System for Motor Vehicles using Environmental Data)
Authors: Müller Mark , Reif Markus , Pandit Madhukar , Staiger Wolfgang
Published: April 2004

Der Beitrag beschäftigt sich mit Strategien und Algorithmen für die optimale Gangwahl bei Kraftfahrzeugen mit automatisiertem Getriebe. Zum Zweck der Simulation wurde ein vorausschauendes Fahrermodell entwickelt. Darüber hinaus entstand eine Funktion zur Prädiktion der Fahrzeug-Geschwindigkeit, welche sowohl in der Simulation als auch im endgültigen prädiktiven Schaltalgorithmus verwendet wird. Der Aufbau wird beschrieben und die Funktion sowohl in der Simulation als auch auf der Straße getestet.
Entwicklung und Analyse zeitgesteuerter Systeme (Development and Analysis of Time-Triggered Systems)
Authors: Ringler Thomas
Published: April 2004

Zeitgesteuerte Systeme versprechen die Anforderungen zukünftiger By-Wire-Systeme in Automobilen zu erfüllen. Die Zeitsteuerung erfordert neue Verfahren und Werkzeugkonzepte. In dem vorliegenden Aufsatz wird ein Verfahren zur Entwicklung und Analyse zeitgesteuerter Systeme vorgestellt. Aktivitäten zur Entwicklung zeitgesteuerter Systeme werden identifiziert und in den etablierten Entwicklungsprozess der Automobilindustrie eingegliedert. Die Bestimmung der maximalen Ausführungszeit von Programmen durch die Worst-Case-Execution-Time-Analyse (WCET-Analyse) ist hierfür die Grundlage und bildet den Schwerpunkt. Dem aktuellen Trend in der Automobilindustrie, Software modellbasiert zu erstellen wird Rechnung getragen, indem ein Konzept der modellbasierten WCET-Analyse entwickelt wird.
Navigationsmerkmale und ihre Präferenzwirkung bei e-Shop-Nutzern (Navigation Bar Characteristics and Their Effect on User Preferences)
Authors: Silberer Günter , Engelhardt Jan-Frederik
Published: April 2004

Ein entscheidender Erfolgsfaktor bei der Kundengewinnung und Kaufrealisierung in e-Shops ist die Gestaltung der Mensch-Medium-Schnittstelle. Besondere Bedeutung nimmt dabei die Gestaltung der Navigationsleiste als wichtigste Schnittstellenlösung ein. Hier beurteilt der Shopbesucher unter Berücksichtigung formaler und inhaltlicher Merkmale den Nutzwert des Onlineshops hinsichtlich seiner Intentionsrealisierung. Auf dieser Grundlage wird das weitere Verhalten im Shop geplant und entschieden. Um konkrete Empfehlungen für diesen wichtigen Shopsitebereich zu geben, wurde eine Studie mit dem Ziel durchgeführt, die Nutzenwerte und relativen Wichtigkeiten verschiedener formaler Navigationsleistenmerkmale zu bestimmen. Die Studie zeichnet sich methodisch durch den Rückgriff auf die Conjointanalyse als dekompositionellen Ansatz der Präferenzmessung aus. Der Einsatz der Conjointanalyse als Verfahren zur Beurteilung von Websites ist ein bislang vernachlässigter, aber den kompositionellen Verfahren vermeintlich überlegener Ansatz. Als zentrales Ergebnis der Untersuchung kann festgehalten werden, dass nur gering oder schwach aktivierende Elemente verwendet werden sollten. Eine als aufdringlich empfundene Navigationsgestaltung wird abgelehnt.
Entdeckung und Nutzbarmachung von stillem Wissen in heterogenen Expertengemeinschaften – das Projekt AWAKE (Uncovering and Utilization of Tacit Knowledge in Heterogeneous Expert Communities)
Authors: Novak Jasminko , Kunz Christoph , Wurst Michael
Published: April 2004

In diesem Beitrag beschreiben wir die in dem AWAKE – Networked Awareness for Knowledge Discovery - Projekt entwickelten Ansätze, Lösungen und Prototypen zur empirischen Untersuchung der Frage, wie implizite Wissensstrukturen in unterschiedlichen Expertengemeinschaften entdeckt, visualisiert und für diese nutzbar gemacht werden können. Der Schwerpunkt liegt dabei auf dem entwickelten Modell sowie dem System zur Erstellung und kollaborativen Nutzung von personalisierten Wissenskarten und kollaborativen Begriffsnetzen. Zu den Anwendungsszenarien gehören die automatische Generierung von personalisierten Wissensportalen, kollaborative semantische Exploration von komplexen Informationsräumen und der Aufbau von gemeinschaftlichen Terminologienetzwerken in formalisierten Ontologien. Die entwickelten Prototypen verbinden automatische Textanalyse mit maschinellem Lernen und Nutzerschnittstellen zur Visualisierung von Kontexten und Beziehungen sowie zum Aufbau neuer Wissensstrukturen. Als Entwicklungskontext und empirische Testumgebung diente die Internetplattform netzspannung.org, ein Wissensportal das digitale Kunst, Kultur und Informationstechnologie verbindet.
Trends in adolescent alcohol and other drug use: findings from three sentinel sites in South Africa (1997–2001)
Authors: Parry Charles D.H , Myers Bronwyn , Morojele Neo K , Flisher Alan J , Bhana Arvin , Donson Hilton , Plüddemann Andreas
Published: April 2004

This paper aims to provide surveillance information about the extent and consequences of alcohol and other drug (AOD) use by adolescents for three sentinel sites in South Africa (Cape Town, Durban and Gauteng province). From 1997 to 2001, data were gathered from multiple sources, including specialist treatment centres, trauma units, school students, rave party attenders, and arrestees. Since the start of surveillance, an increasing proportion of South African adolescents are using AODs. Surveys point to high levels of alcohol misuse among high school students, with alcohol being the most common substance of abuse. Cannabis is the most frequently reported illicit drug of abuse among adolescents. This is reflected in the large proportion of adolescents receiving treatment for cannabis, cannabis‐positive arrestees, and cannabis‐positive trauma patients. Cannabis smoked together with methaqualone is the second most common primary drug of abuse in Cape Town. Arrestee data highlights the potentially negative effect of adolescent methaqualone use. Cocaine and heroin are emerging as problem drugs of abuse among adolescents in large metropolitan centres. Ecstasy (MDMA) use occurs mainly among adolescents who attend rave parties and clubs. The study points to the need for AOD intervention programmes that target young people and the need for continued monitoring of adolescent AOD use in the future.
Development and validation of a depression scale for Asian adolescents
Authors: Woo Bernardine S.C. , Chang W.C. , Fung Daniel S.S. , Koh Jessie B.K. , Leong Joyce S.F. , Kee Carolyn H.Y. , Seah Cheryl K.F.
Published: April 2004

Items covering both core and culture‐specific facets of depression were generated based on literature review and clinical experience. They were modified following focus group discussions with depressed adolescents and adolescents in the community. The newly constructed Asian Adolescent Depression Scale (AADS) was administered to a clinical and a community sample of adolescents together with other rating scales. The AADS comprised 4 factors (negative self‐evaluation, negative affect, cognitive inefficiency and lack of motivation) and demonstrated sound psychometric properties. Negative socially oriented self‐evaluation and cognitive inefficiency were important in Singaporean adolescents’ conceptualization of depression and are likely to be Asian culture‐specific dimensions.
Challenging times: a study to detect Irish adolescents at risk of psychiatric disorders and suicidal ideation
Authors: Lynch Fionnuala , Mills Carla , Daly Irenee , Fitzpatrick Carol
Published: April 2004

Suicide rates in young Irish males have risen markedly in the past 10 years, and suicide is now the leading cause of death in young men in the 15–24‐year‐old age range.

This is the first large‐scale study in Ireland that set out to identify young people at risk of psychiatric disorders, including depressive disorders, and suicidal ideation. Seven hundred and twenty three school‐going adolescents aged 12–15 years were screened using the Children's Depression Inventory and the Strengths and Difficulties Questionnaire. 19.4% were identified as being ‘at risk’ of having a mental health disorder. Of this ‘at risk’ group, 12.1% expressed possible suicidal intent and 45.7% expressed suicidal ideation. Of the 583 adolescents identified as being ‘not at risk’, 13% expressed suicidal ideation while none expressed suicidal intent. Being ‘at risk’ was not related to gender or to socio‐economic status. Those living with two parents were significantly more likely to be in the ‘not at risk’ group. Girls attending co‐educational schools were twice as likely to be in ‘at risk’ group compared with those attending all girls schools, while school type was not a risk factor for boys.

This study shows that, as in other western countries, there are large numbers of young Irish people at risk of mental health disorders and suicidal ideation in the community, and raises the question of the importance of mental health promotion in our education system.
α‐Synuclein regulation of the dopaminergic transporter: a possible role in the pathogenesis of Parkinson's disease
Authors: Sidhu Anita , Wersinger Christophe , Vernier Philippe
Published: April 2004

Parkinson's disease (PD) is a slow progressive neurodegenerative disorder. Recent evidence suggests a central role for α‐synuclein, a protein of unknown function, in the genesis of PD. The phenomenon of selective degeneration of dopaminergic neurons in PD may be linked to the potential toxicity of dopamine itself and aberrations in the processes which regulate dopamine content may underlie the pathogenesis of this disease. Here, we review a vital role of α‐synuclein in the modulation of dopamine transporter (DAT) function, and describe how disruption of this modulatory process permits increased re‐uptake of high levels of intracellular dopamine by DAT, causing profound neurotoxicity.
Plant chromatin – epigenetics linked to ATP‐dependent remodeling and architectural proteins
Authors: Brzeski Jan , Jerzmanowski Andrzej
Published: April 2004

Studies in organisms belonging to different eukaryotic kingdoms have revealed that the structural state of chromatin is controlled by interactions of DNA, small RNAs and specific proteins, linked to a self‐reinforcing complex network of biochemical activities involving histone and DNA modifications and ATP‐dependent nucleosome remodeling. However, these findings must now be reinterpreted in light of the recent discovery of the highly dynamic character of interphase chromosomes exemplified by the constant flux of enzymatic and structural proteins through both eu‐ and heterochromatin and by short‐ and long‐range chromosome movements in the nucleus. The available data on chromosome organization in Arabidopsis thaliana and links between proteins influencing chromatin structure and DNA and histone modifications documented in this model plant provide strong supportive evidence for the dynamic nature of chromosomes.
Matrix metalloproteinases and their endogenous inhibitors in neuronal physiology of the adult brain
Authors: Dzwonek Joanna , Rylski Marcin , Kaczmarek Leszek
Published: April 2004

More than 20 matrix metalloproteinases (MMPs) and four of their endogenous tissue inhibitors (TIMPs) act together to control tightly temporally restricted, focal proteolysis of extracellular matrix. In the neurons of the adult brain several components of the TIMP/MMP system are expressed and are responsive to changes in neuronal activity. Furthermore, functional studies, especially involving blocking of MMP activities, along with the identification of MMP substrates in the brain strongly suggest that this enzymatic system plays an important physiological role in adult brain neurons, possibly being pivotal for neuronal plasticity.
Mapping of the insulin‐like growth factor II binding site of the Type I insulin‐like growth factor receptor by alanine scanning mutagenesis
Authors: Sørensen Heidi , Whittaker Linda , Hinrichsen Jane , Groth Andreas , Whittaker Jonathan
Published: April 2004

The Type I insulin‐like growth factor receptor is a physiological receptor for insulin‐like growth factor II (IGF‐II). To characterize the molecular basis of the receptor's ligand binding properties, we have examined the effects of alanine mutations of residues in the ligand binding site of the receptor on its affinity for IGF‐II. The functional epitope for IGF‐II comprises residues in the N‐terminal L1 domain and residues at the C‐terminus of the α subunit. Cysteine rich domain residues do not appear to be critical for IGF‐II binding.
Furin cleavage of the HIV‐1 Tat protein
Authors: Tikhonov Ilia , Ruckwardt Tracy J. , Berg Shannon , Hatfield Glen S. , David Pauza C.
Published: April 2004

Extracellular human immunodeficiency virus‐1 (HIV‐1) Tat protein and Tat‐derived peptides are biologically active but mechanisms of Tat processing are not known. Within the highly conserved basic region of HIV‐1 Tat protein (amino acids, a.a. 48–56), we identified two putative furin cleavage sites and showed that Tat protein was cleaved in vitro at the second site, RQRR↓ (a.a. 53–56↓). This in vitro cleavage was blocked by a monoclonal antibody that binds near the cleavage site or by the furin inhibitor α‐1 PDX. Monocytoid cells rich in furin also degraded Tat and this process was slowed by the furin inhibitor or the specific monoclonal antibody. Furin processing did not affect the rates for Tat uptake and nuclear accumulation in HeLa or Jurkat cells, but the transactivation activity was greatly reduced. Furin processing is a likely mechanism for inactivating extracellular HIV‐1 Tat protein.
Identification of an Arabidopsis inorganic pyrophosphatase capable of being imported into chloroplasts
Authors: Schulze Silke , Mant Alexandra , Kossmann Jens , Lloyd James R.
Published: April 2004

An Arabidopsis cDNA coding for a previously uncharacterized isoform of inorganic pyrophosphatase was isolated. It was used to complement an E. coli mutant, demonstrating that it coded for an active enzyme. MgCl2 was necessary for the protein's activity, whilst NaF inhibited it. The K
m for pyrophosphate and the pH optimum of the protein was determined. The gene coding for this protein was expressed in all tissues, and its expression in rosette leaves was induced by incubation on metabolizable sugars. In vitro import experiments demonstrated that the protein could be imported into chloroplasts and localized to the stromal compartment.
Cellular growth inhibition by TGF‐β1 involves IRS proteins
Authors: Huang Shuan Shian , Leal Sandra M. , Chen Chun-Lin , Liu I-Hua , Huang Jung San
Published: April 2004

In Mv1Lu cells, insulin partially reverses transforming growth factor‐β1 (TGF‐β1) growth inhibition in the presence of α5β1 integrin antagonists. TGF‐β1 appears to induce phosphorylation of IRS‐2 in these cells; this is inhibited by a TGF‐β antagonist known to reverse TGF‐β growth inhibition. Stable transfection of 32D myeloid cells (which lack endogenous IRS proteins and are insensitive to growth inhibition by TGF‐β1) with IRS‐1 or IRS‐2 cDNA confers sensitivity to growth inhibition by TGF‐β1; this IRS‐mediated growth inhibition can be partially reversed by insulin in 32D cells stably expressing IRS‐2 and the insulin receptor (IR). These results suggest that growth inhibition by TGF‐β1 involves IRS proteins.
Bidirectional role of orphan nuclear receptor RORα in clock gene transcriptions demonstrated by a novel reporter assay system
Authors: Nakajima Yoshihiro , Ikeda Masaaki , Kimura Takuma , Honma Sato , Ohmiya Yoshihiro , Honma Ken-ichi
Published: April 2004

Circadian rhythms are generated by an extremely complicated transcription–translation feedback loop. To precisely analyze the molecular mechanisms of the circadian clock, it is critical to monitor multiple gene expressions and/or interactions with their transcription factors simultaneously. We have developed a novel reporter assay system, the tricolor reporter in vitro assay system, which consists of green‐ and red‐emitting Phrixothrix luciferases as dual reporters and blue‐emitting Renilla luciferase as internal control. We have successfully employed this system in analyzing the effects of clock gene products on the enhancer elements of Per1 and Bmal1 promoters. The results indicate that the orphan nuclear receptor RORα regulates bidirectionally Bmal1 (positively) and Per1 (negatively) transcriptions simultaneously.