@phdthesis{Mueller2008,
  author    = {M{\"u}ller, Melanie J. I.},
  title     = {Bidirectional transport by molecular motors},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18715},
  school      = {Universit{\"a}t Potsdam},
  year      = {2008},
  abstract  = {In biological cells, the long-range intracellular traffic is powered by molecular motors which transport various cargos along microtubule filaments. The microtubules possess an intrinsic direction, having a 'plus' and a 'minus' end. Some molecular motors such as cytoplasmic dynein walk to the minus end, while others such as conventional kinesin walk to the plus end. Cells typically have an isopolar microtubule network. This is most pronounced in neuronal axons or fungal hyphae. In these long and thin tubular protrusions, the microtubules are arranged parallel to the tube axis with the minus ends pointing to the cell body and the plus ends pointing to the tip. In such a tubular compartment, transport by only one motor type leads to 'motor traffic jams'. Kinesin-driven cargos accumulate at the tip, while dynein-driven cargos accumulate near the cell body. We identify the relevant length scales and characterize the jamming behaviour in these tube geometries by using both Monte Carlo simulations and analytical calculations. A possible solution to this jamming problem is to transport cargos with a team of plus and a team of minus motors simultaneously, so that they can travel bidirectionally, as observed in cells. The presumably simplest mechanism for such bidirectional transport is provided by a 'tug-of-war' between the two motor teams which is governed by mechanical motor interactions only. We develop a stochastic tug-of-war model and study it with numerical and analytical calculations. We find a surprisingly complex cooperative motility behaviour. We compare our results to the available experimental data, which we reproduce qualitatively and quantitatively.},
  language  = {en}
}
@phdthesis{Imranulhaq2008,
  author    = {Imran ul-haq, Muhammad},
  title     = {Synthesis of fluorinated polymers in supercritical carbon dioxide (scCO₂)},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-19868},
  school      = {Universit{\"a}t Potsdam},
  year      = {2008},
  abstract  = {For the first time stabilizer-free vinylidene fluoride (VDF) polymerizations were carried out in homogeneous phase with supercritical CO₂. Polymerizations were carried out at 140°C, 1500 bar and were initiated with di-tert-butyl peroxide (DTBP). In-line FT-NIR (Fourier Transform- Near Infrared) spectroscopy showed that complete monomer conversion may be obtained. Molecular weights were determined via size-exclusion chromatography (SEC) and polymer end group analysis by 1H-NMR spectroscopy. The number average molecular weights were below 104 g∙mol-1 and polydispersities ranged from 3.1 to 5.7 depending on DTBP and VDF concentration. To allow for isothermal reactions high CO₂ contents ranging from 61 to 83 wt.\% were used. The high-temperature, high-pressure conditions were required for homogeneous phase polymerization. These conditions did not alter the amount of defects in VDF chaining. Scanning electron microscopy (SEM) indicated that regular stack-type particles were obtained upon expansion of the homogeneous polymerization mixture. To reduce the required amount of initiator, further VDF polymerizations using chain transfer agents (CTAs) to control molecular weights were carried out in homogeneous phase with supercritical carbon dioxide (scCO₂) at 120 °C and 1500 bar. Using perfluorinated hexyl iodide as CTA, polymers of low polydispersity ranging from 1.5 to 1.2 at the highest iodide concentration of 0.25 mol·L-1 were obtained. Electrospray ionization- mass spectroscopy (ESI-MS) indicates the absence of initiator derived end groups, supporting livingness of the system. The "livingness" is based on the labile C-I bond. However, due to the weakness of the C-I bond perfluorinated hexyl iodide also contributes to initiation. To allow for kinetic analyses of VDF polymerizations the CTA should not contribute to initiation. Therefore, additional CTAs were applied: BrCCl3, C6F13Br and C6F13H. It was found that C6F13H does not contribute to initiation. At 120°C and 1500 bar kp/kt0.5~ 0.64 (L·mol-1·s-1)0.5 was derived. The chain transfer constant (CT) at 120°C has been determined to be 8·10-1, 9·10-2 and 2·10-4 for C6F13I, C6F13Br and C6F13H, respectively. These CT values are associated with the bond energy of the C-X bond. Moreover, the labile C-I bond allows for functionalization of the polymer to triazole end groups applying click reactions. After substitution of the iodide end group by an azide group 1,3 dipolar cycloadditions with alkynes yield polymers with 1,2,3 triazole end groups. Using symmetrical alkynes the reactions may be carried out in the absence of any catalyst. This end-functionalized poly (vinylidene fluoride) (PVDF) has higher thermal stability as compared to the normal PVDF. PVDF samples from homogeneous phase polymerizations in supercritical CO₂ and subsequent expansion to ambient conditions were analyzed with respect to polymer end groups, crystallinity, type of polymorphs and morphology. Upon expansion the polymer was obtained as white powder. Scanning electron microscopy (SEM) showed that DTBP derived polymer end groups led to stack-type particles whereas sponge- or rose-type particles were obtained in case of CTA fragments as end groups. Fourier-Transform Infrared spectroscopy and wide angle X-ray diffraction indicated that the type of polymorph, α or β crystal phase was significantly affected by the type of end group. The content of β-phase material, which is responsible for piezoelectricity of PVDF, is the highest for polymer with DTBP-derived end groups. In addition, the crystallinity of the material, as determined via differential scanning calorimetry is affected by the end groups and polymer molecular weights. For example, crystallinity ranges from around 26 \% for DTBP-derived end groups to a maximum of 62 \% for end groups originating from perfluorinated hexyl iodide for polymers with Mn ~2200 g·mol-1. Expansion of the homogeneous polymerization mixture results in particle formation by a non-optimized RESS (Rapid Expansion from Supercritical Solution) process. Thus, it was tested how polymer end groups affect the particles size distribution obtained from RESS process under controlled conditions (T = 50°C and P = 200 bar). In all RESS experiments, small primary PVDF with diameters less than 100 nm without the use of liquid solvents, surfactants, or other additives were produced. A strong correlation between particle size and particle size distribution with polymer end groups and molecular weight of the original material was observed. The smallest particles were found for RESS of PVDF with Mn~ 4000 g·mol-1 and PFHI (C6F13I) - derived end groups.},
  language  = {en}
}
@misc{KoechyBrakenhielm2008,
  author    = {K{\"o}chy, Martin and Br{\aa}kenhielm, Sven},
  title     = {Separation of effects of moderate N deposition from natural change in ground vegetation of forests and bogs},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16621},
  year      = {2008},
  abstract  = {The effect of moderate rates of nitrogen deposition on ground floor vegetation is poorly predicted by uncontrolled surveys or fertilization experiments using high rates of nitrogen (N) addition. We compared the temporal trends of ground floor vegetation in permanent plots with moderate (7-13 kg ha-1 year-1) and lower bulk N deposition (4-6 kg ha-1 year-1) in southern Sweden during 1982-1998. We examined whether trends differed between growth forms (vascular plants and bryophytes) and vegetation types (three types of coniferous forest, deciduous forest, and bog). Trends of site-standardized cover and richness varied among growth forms, vegetation types, and deposition regions. Cover in spruce forests decreased at the same rate with both moderate and low deposition. In pine forests cover decreased faster with moderate deposition and in bogs cover decreased faster with low deposition. Cover of bryophytes in spruce forests increased at the same rate with both moderate and low deposition. In pine forests cover decreased faster with moderate deposition and in bogs and deciduous forests there was a strong non-linear increase with moderate deposition. The trend of number of vascular plants was constant with moderate and decreased with low deposition. We found no trend in the number of bryophyte species. We propose that the decrease of cover and number with low deposition was related to normal ecosystem development (increased shading), suggesting that N deposition maintained or increased the competitiveness of some species in the moderate-deposition region. Deposition had no consistent negative effect on vegetation suggesting that it is less important than normal successional processes.},
  language  = {en}
}
@inproceedings{Piskorski2008,
  author    = {Piskorski, Jakub},
  title     = {ExPRESS : extraction pattern recognition engine and specification suite},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-27227},
  year      = {2008},
  abstract  = {The emergence of information extraction (IE) oriented pattern engines has been observed during the last decade. Most of them exploit heavily finite-state devices. This paper introduces ExPRESS - a new extraction pattern engine, whose rules are regular expressions over flat feature structures. The underlying pattern language is a blend of two previously introduced IE oriented pattern formalisms, namely, JAPE, used in the widely known GATE system, and the unificationbased XTDL formalism used in SProUT. A brief and technical overview of ExPRESS, its pattern language and the pool of its native linguistic components is given. Furthermore, the implementation of the grammar interpreter is addressed too.},
  language  = {en}
}
@article{Kauschke2008,
  author    = {Kauschke, Christina},
  title     = {Fr{\"u}he lexikalische Verz{\"o}gerung als Indikator f{\"u}r SSES?},
  series = {Spektrum Patholinguistik},
  journal   = {Spektrum Patholinguistik},
  number    = {1},
  issn      = {1866-9085},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18902},
  pages     = {19 -- 38},
  year      = {2008},
  abstract  = {Auszug: Seit langem ist bekannt, dass Kinder mit Sprachentwicklungsst{\"o}rungen meist schon in einem fr{\"u}hen Stadium ihrer Sprachentwicklung auffallen: die ersten W{\"o}rter werden versp{\"a}tet produziert, der Wortschatz w{\"a}chst langsamer an, der Vokabularspurt setzt verz{\"o}gert ein oder bleibt aus, so dass das produktive Vokabular mit zwei Jahren weniger als 50 W{\"o}rter umfasst. Außerdem treten keine Wortkombinationen auf. Obwohl bei nahezu jeder Sprachentwicklungs-st{\"o}rung retrospektiv derartige fr{\"u}he Anzeichen auszumachen sind, m{\"u}ndet andererseits nicht jede fr{\"u}he Verz{\"o}gerung in eine anhaltende St{\"o}rung. Diese Beobachtung hat Anlass zu einer regen Forschungst{\"a}tigkeit gegeben. Im Zentrum steht die Frage, anhand welcher Kriterien sich der weitere Entwicklungsverlauf eines sprachlich verz{\"o}gerten Kindes prognostizieren l{\"a}sst. Der Forschungsstand zu diesem Bereich wurde an anderer Stelle bereits ausf{\"u}hrlich beschrieben (z. B. in Kauschke 2000, 2003, 2006a). In diesem Beitrag m{\"o}chte ich die Entwicklungswege dieser Population anhand aktueller Studien skizzieren, die Problematik der Pr{\"a}diktion ansprechen und eine Studie {\"u}ber Sprachentwicklungsverl{\"a}ufe im dritten Lebensjahr vorstellen, in der ungest{\"o}rte Kinder und sprachlich verz{\"o}gerte l{\"a}ngsschnittlich beobachtet wurden. Es folgen {\"U}berlegungen zur Therapienotwendigkeit und Therapiekonzeption, die durch die Darstellung eines exemplarischen Therapieverlaufs bei einem Einzelfall illustriert werden. [...]},
  language  = {de}
}
@article{Glueck2008,
  author    = {Gl{\"u}ck, Christian W.},
  title     = {Diagnostik semantisch-lexikalischer F{\"a}higkeiten im Grundschulalter mit dem WWT 6-10},
  series = {Spektrum Patholinguistik},
  journal   = {Spektrum Patholinguistik},
  number    = {1},
  issn      = {1866-9085},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18912},
  pages     = {39 -- 55},
  year      = {2008},
  abstract  = {Auszug: Etwa zwei Drittel aller Ausgaben der Krankenkassen f{\"u}r das Heilmittel Sprachtherapie betreffen ein Klientel in der Altersgruppe der 0- bis 15-j{\"a}hrigen (GVK-HIS Bundesrepublik 2007). Spracherwerbsst{\"o}rungen stellen das h{\"a}ufigste Entwicklungsrisiko bei Kindern dar. Ca. 18\% der einzuschulenden Kinder weisen einen F{\"o}rderbedarf im Entwicklungsbereich Sprache auf (Tollk{\"u}hn 2001) und ca. 18\% der 6-j{\"a}hrigen Jungen erhalten nach dem Heilmittelbericht 2006 Sprachtherapieverordnungen (Schr{\"o}der \& Waltersbacher 2006). Die {\"u}berwiegende Mehrheit erh{\"a}lt diese Verordnung aufgrund der Zuweisung des Indikationsschl{\"u}ssels „St{\"o}rungen der Sprache vor Abschluss der Sprachentwicklung". Darunter fallen v.a. Kinder mit einer prim{\"a}ren Spracherwerbsst{\"o}rung, f{\"u}r deren Art und Ausmaß keine H{\"o}rst{\"o}rung, keine Intelligenzbeeintr{\"a}chtigung, keine neurologische Sch{\"a}digung oder soziale Deprivation verantwortlich gemacht werden kann. F{\"u}r diese besondere Entwicklungssituation wird die Diagnose „Spezifische Spracherwerbsst{\"o}rung (SSES)" vergeben (Grimm 2003; Dannenbauer 2002). [...]},
  language  = {de}
}
@article{Wahl2008,
  author    = {Wahl, Michael},
  title     = {EKP-Befunde subkortikaler Syntaxverarbeitung},
  series = {Spektrum Patholinguistik},
  journal   = {Spektrum Patholinguistik},
  number    = {1},
  issn      = {1866-9085},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18972},
  pages     = {119 -- 130},
  year      = {2008},
  abstract  = {Auszug: Aphasien sind variable Sprachst{\"o}rungen, die auf umschriebene Hirnl{\"a}sionen zur{\"u}ckf{\"u}hrbar sind und die Produktion und Verst{\"a}ndnis separat oder kombiniert betreffen (Weniger 2003). Hierbei wird das klinische Syndrom oft mit der Lokalisation der morphologischen Gehirndefekte (z. B. durch Hirn-infarkte oder -blutungen oder Tumoren) korreliert. Sprachkompetenz gilt in erster Linie als eine Leistung des Kortex, jedoch wurden v. a. im Zuge sich verbessernder bildgebender Verfahren aphasische Syndrome auch nach L{\"a}sionen subkortikaler Hirnregionen, insbesondere der Basalganglien und des Thalamus nachgewiesen (Wallesch \& Papagno 1988; Friston et al. 1993; Nadeau \& Crosson 1997; Zoppelt \& Daum 2003; DeWitte et al. 2006; Wahl in Druck). Diese Strukturen liegen in der Tiefe des Gehirns und kommunizieren {\"u}ber weit gef{\"a}cherte Faserverbindungen mit dem Kortex. In erster Linie werden den Basalganglien senso-motorische Kontrollfunktionen zugewiesen (Alexander et al. 1986). Diverse Erkrankungen, die durch St{\"o}rungen physiologischer Bewegungsabl{\"a}ufe gekennzeichnet sind (z. B. Morbus Parkinson, Chorea Huntington), werden auf Funktionsdefekte dieser Strukturen zur{\"u}ckgef{\"u}hrt. Hierbei wurde der Thalamus h{\"a}ufig als Relais-Station des Informationsaustauschs zwischen anatomisch entfernten Arealen des Nervensystems aufgefasst. Basalganglien und Thalamus jedoch k{\"o}nnen dar{\"u}ber hinausgehende Funktionen, z. B. zur Bereitstellung, Aufrechterhaltung und Auslenkung von Aufmerksamkeit bei der Bearbeitung kognitiver Aufgaben, zugesprochen werden (Cavedini et al. 2006; Piguet et al. 2006; Klostermann et al. 2006; Marzinzik et al. 2008). [...]},
  language  = {de}
}
@misc{Hippler2008,
  author    = {Hippler, Jochen},
  title     = {Krise in Pakistan},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-23273},
  year      = {2008},
  language  = {de}
}
@misc{Timmermann2008,
  author    = {Timmermann, Heinz},
  title     = {Belarus von außen demokratisieren?},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-23328},
  year      = {2008},
  abstract  = {Inhalt: Risse im Lukaschenko-Regime Demokratisierung von außen? Handlungsoptionen europ{\"a}ischer Akteure Russland als wichtiger Einflussfaktor},
  language  = {de}
}
@misc{Koetter2008,
  author    = {K{\"o}tter, Wolfgang},
  title     = {T{\"o}dliches Menetekel f{\"u}r die Menschheit : Abr{\"u}stung am Anfang des 21. Jahrhunderts},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-23369},
  year      = {2008},
  abstract  = {Atomare, biologische und chemische Waffen bedrohen das {\"U}berleben der Menschheit. Friedens- und Konfliktforscher Wolfgang K{\"o}tter aus Potsdam untersucht die differenzierten Ergebnisse bei der Beseitigung dieser Gefahr. W{\"a}hrend die chemische Abr{\"u}stung, wenn auch mit Verz{\"o}gerungen, voran kommt, fehlt dem Verbot der B-Waffen ein wirksames Kontrollinstrument. Atomare Waffen erleben sogar eine Renaissance und das nukleare Nichtverbreitungsregime droht zu zerbrechen.},
  language  = {de}
}