Global ETD Search

131	Laut, Ton, Stärke Schreiner, Florian 03 May 2010 (has links) Historisch wird die Arbeit von zwei Daten her begrenzt, von den ersten hör-physiologischen Experimenten seit 1850, und von den massenwirksamen akustischen Inszenierungen der 1930er Jahre in „real auditory perspective“. Die Arbeit beginnt in Kapitel I mit dem tragischen Fall des Regisseurs und langjährigen Psychiatrie-Patienten Antonin Artaud, der die Sprache zugunsten von Lauten, Gebärden und Schreien verlässt. Seine Experimente zum Theater geben zu einer ersten Korrektur von Bildlichkeit Anlass. In Kapitel II wird der Vorrang der Bildlichkeit grundsätzlich in Frage gestellt, die Differenz von Bild und Klang wissenschaftshistorisch auseinandergesetzt, und ein „acoustic turn“ zur Welt vorbereitet. Die Untersuchungen des Physiologen und Akustikers Hermann von Helmholtz sind hier maßgeblich, denn sie beeinflussen die Technische Akustik von ihren Anfängen her. Das Kapitel III schließlich untersucht im transatlantischen Vergleich die technischen Bedingungen nach 1900. Die Beschallungsanlage hat nun die Fähigkeit, alltäglich in den Dienst genommen zu werden, und auch politischen Manipulationen diensthaft zu sein. / Historically the work is framed by two dates, by the physiological experiments of hearing and the mise en scène of a massed and sonic attack in so called „real auditory perspective“ of the 1930s. The first chapter starts with the tragedic and long living psychiatric case Antonin Artaud, who moves away from clarity of sounds to phones, gestures and crying. Such experiments give cause for a fundamental rethinking of meaning in the sense of picture, and leads to the second chapter which argues in more detail for the lap of our sonic understanding of the world. This way speeds up to an „acoutic turn“ by a retour to the biological grounds of sonic perception. The physiological and acoustic inquiries of Hermann von Helmholtz fit here to the ground for him being starting point of what will later be called „technische Akustik“. The third chapter bridges Europe´s early Telefunken-years with the United States and their chief acousticians at the legendary Bell Laboratories, and seeks finally for light in scientific amnesia against progress and control, or what the germans call „Betriebsamkeit“ and „Gestell.“ (Heidegger) Metaphysik Induktion Theater Abgrund Angst Anlage Befindlichkeit Berührung Beschallung decibel Elektroschock Futurismo Gebärde Gefühlsathletik Glockengeläut Grausamkeit Grund-Stimmung hifi-lofi Hörschwelle Innervation Intonation Klang Kultur-Betrieb Lautheit Lärmpegel Messtechnik Nachbilder Organ Phon Physiologie Präsentabilia Psychophysik Resonanzraum Schrei Sinnestäuschung Sirene Sprach-Losigkeit Sprung Schwingungsweite Stille Subjektil Tonlage Übermächtigung Wüste. sound metrology Abyss fear being touch acoustic irradiation decibel electroshock futurismo gesture athletics of feeling crualty basic tuning hifi-lofi threshold of audability inductivity innervation intonation cultural business loudness noise level metaphysics after-image organ phon physiology praesentabilia psychophysics resonance scream delusion siren loss of speech jump amplitude silence subjectil theater pitch overpowering desert 780 Musik 48 Musik EC 3520 AP 12300 ddc:780
132	In situ three-dimensional reconstruction of mouse heart sympathetic innervation by two-photon excitation fluorescence imaging Freeman, Kim Renee 25 February 2014 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / The sympathetic nervous system strongly modulates the contractile and electrical function of the heart. The anatomical underpinnings that enable a spatially and temporally coordinated dissemination of sympathetic signals within the cardiac tissue are only incompletely characterized. In this work we took the first step of unraveling the in situ 3D microarchitecture of the cardiac sympathetic nervous system. Using a combination of two-photon excitation fluorescence microscopy and computer-assisted image analyses, we reconstructed the sympathetic network in a portion of the left ventricular epicardium from adult transgenic mice expressing a fluorescent reporter protein in all peripheral sympathetic neurons. The reconstruction revealed several organizational principles of the local sympathetic tree that synergize to enable a coordinated and efficient signal transfer to the target tissue. First, synaptic boutons are aligned with high density along much of axon-cell contacts. Second, axon segments are oriented parallel to the main, i.e., longitudinal, axes of their apposed cardiomyocytes, optimizing the frequency of transmitter release sites per axon/per cardiomyocyte. Third, the local network was partitioned into branched and/or looped sub-trees which extended both radially and tangentially through the image volume. Fourth, sub-trees arrange to not much overlap, giving rise to multiple annexed innervation domains of variable complexity and configuration. The sympathetic network in the epicardial border zone of a chronic myocardial infarction was observed to undergo substantive remodeling, which included almost complete loss of fibers at depths >10 µm from the surface, spatially heterogeneous gain of axons, irregularly shaped synaptic boutons, and formation of axonal plexuses composed of nested loops of variable length. In conclusion, we provide, to the best of our knowledge, the first in situ 3D reconstruction of the local cardiac sympathetic network in normal and injured mammalian myocardium. Mapping the sympathetic network connectivity will aid in elucidating its role in sympathetic signal transmisson and processing. Microscopy Multi-photon Two-Photon TPLSM Confocal GFP Sympathetic Nervous System Cardiac Neuron Heart Cardiomyocyte Fluorescence microscopy -- Research Multiphoton excitation microscopy Confocal microscopy Neurons Cellular signal transduction Muscle cells Myocardial infarction -- Research Myocardium Heart -- Pathophysiology Two-photon absorbing materials Heart -- Imaging Cardiovascular system -- Innervation Neuromuscular transmission Mice as laboratory animals -- Research
133	Functional contributions of a sex-specific population of myelinated aortic baroreceptors in rat and their changes following ovariectomy Santa Cruz Chavez, Grace C. January 2014 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / Gender differences in the basal function of autonomic cardiovascular control are well documented. Consistent baroreflex (BRx) studies suggest that women have higher tonic parasympathetic cardiac activation compared to men. Later in life and concomitant with menopause, a significant reduction in the capacity of the BRx in females increases their risk to develop hypertension, even exceeding that of age-matched males. Loss of sex hormones is but one factor. In female rats, we previously identified a distinct myelinated baroreceptor (BR) neuronal phenotype termed Ah-type, which exhibits functional dynamics and ionic currents that are a mix of those observed in barosensory afferents functionally identified as myelinated A-type or unmyelinated C-type. Interestingly, Ah-type afferents constitute nearly 50% of the total population of myelinated aortic BR in female but less than 2% in male rat. We hypothesized that an afferent basis for sexual dimorphism in BRx function exists. Specifically, we investigated the potential functional impact Ah-type afferents have upon the aortic BRx and what changes, if any, loss of sex hormones through ovariectomy brings upon such functions. We assessed electrophysiological and reflexogenic differences associated with the left aortic depressor nerve (ADN) from adult male, female, and ovariectomized female (OVX) Sprague-Dawley rats. Our results revealed sexually dimorphic conduction velocity (CV) profiles. A distinct, slower myelinated fiber volley was apparent in compound action potential (CAP) recordings from female aortic BR fibers, with an amplitude and CV not observed in males. Subsequent BRx studies demonstrated that females exhibited significantly greater BRx responses compared to males at myelinated-specific intensities. Ovariectomy induced an increased overall temporal dispersion in the CAP of OVX females that may have contributed to their attenuated BRx responses. Interestingly, the most significant changes in depressor dynamics occurred at electrical thresholds and frequencies most closely aligned with Ah-type BR fibers. Collectively, we provide evidence that, in females, two anatomically distinct myelinated afferent pathways contribute to the integrated BRx function, whereas in males only one exists. These functional differences may partly account for the enhanced control of blood pressure in females. Furthermore, Ah-type afferents may provide a neuromodulatory pathway uniquely associated with the hormonal regulation of BRx function. Baroreceptor Baroreflex Nerve electrophysiology Ovariectomy Sex differences Cardiovascular Electrophysiology -- Technique Neurophysiology -- Research Baroreceptors -- Research -- Evaluation Baroreflexes -- Research -- Evaluation Ovariectomy -- Research Medicine -- Research -- Sex differences Hypertension -- Women Neural conduction -- Measurement Cardiography Hormones, Sex Menopause Cardiovascular system -- Innervation

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