Synaptic input from CA3 pyramidal cells to dentate basket cells in rat hippocampus.

1. Excitatory inputs from CA3 pyramidal cells to dentate basket cells were examined using the whole-cell recording technique in neonatal (10-16 days) rat hippocampal slices to characterize this unexpected feedback pathway. 2. Minimal electrical stimulation of the CA3 pyramidal layer evoked in basket cells short latency (5.2 +/- 0.4 ms) glutamate receptor-mediated excitatory postsynaptic currents (EPSCs) with fast rise times (at -70 mV, 0.9 +/- 0.2 ms), fast decay time constants (3.6 +/- 0.6 ms), and small amplitudes (-14 +/- 3.4 pA). Minimal electrical stimulation evoked monosynaptic EPSCs in only 48 +/- 9.2% of the trials suggesting that the CA3 pyramidal cell to basket cell pathway was unreliable. 3. CA3 pyramidal cell layer stimulation did not antidromically or synaptically activate granule cells but did evoke polysynaptic IPSCs in granule cells, suggesting that the net effect of CA3 pyramidal cell firing on the dentate gyrus was granule cell inhibition. 4. Stimulation of the CA3 pyramidal cell layer evoked both monosynaptic and polysynaptic EPSCs in basket cells, which were eliminated by a knife lesion separating CA3 from the dentate gyrus. The latencies of the EPSCs evoked in 0.6 mM extracellular calcium were the same as the earliest latencies of EPSCs in 1.5 mM calcium, suggesting that those EPSCs were monosynaptic. The polysynaptic input was more prominent in the presence of 10 microM bicuculline, implying that inhibitory GABAergic circuits normally limit this feedback from CA3 to basket cells. 5. In recordings from 103 pairs of CA3 pyramidal cells and dentate basket cells from 11 slices, two polysynaptic connections were found that were active only when the presynaptic CA3 pyramidal neuron fired in bursts. No monosynaptic connections between CA3 pyramidal cells and basket cells were identified indicating that connections between the two cell types may be sparse. 6. Raising the external potassium concentration from 3.5 to 8.5 mM, which elicited burst firing in CA3 pyramidal cells, resulted in a barrage of EPSCs and action potentials in basket cells. In contrast, granule cells neither fired action potentials nor exhibited increased EPSC frequency in elevated potassium but instead received a higher frequency of bicuculline-sensitive IPSCs, consistent with interneuron firing. The CA3 pyramidal cell to basket cell monosynaptic pathway exhibited paired-pulse facilitation as manifested by an increased probability of release, which supports the idea that basket cells were better activated by short trains of action potentials than by single inputs

Outsourcing the Helicopter Combat Support mission aboard Military Sealift Command ships: a cost comparison study

Recently the Department of Defense and the Navy have sought new avenues for achieving the national security of the United States within the scope of available resources. In an attempt to meet savings objectives, the Navy has looked toward outsourcing the Helicopter Combat Support (HC) mission aboard Military Sealift Command (MSC) ships. After several evaluations with civilian helicopter companies, the Navy awarded Geo-Seis Helicopters, Inc. a three-year contract for ship-to-ship and ship-to-shore logistics services. This thesis evaluates the current outsource contract and compares costs of the contract to those of the HC community. The purpose was to determine the level of savings and the differences in services provided. Within the course of this study, the total in-house cost was established for the HC squadrons flying the H-46 aircraft. This cost was then fractured down to equal the services provided by the contractor to determine the Most Efficient Organization. This thesis determined that the current outsource contract does provide a small savings but at the costs of increased risk in not meeting surge requirements for unplanned contingencies. Furthermore, inherent risks are associated with the inability to not fill personnel billets within other areas of the Navy through reduced manning levels due to outsourcing.http://archive.org/details/outsourcinghelic109459283U.S. Navy (U.S.N.) author.Approved for public release; distribution is unlimited

Electric Fields Due to Synaptic Currents Sharpen Excitatory Transmission

The synaptic response waveform, which determines signal integration properties in the brain, depends on the spatiotemporal profile of neurotransmitter in the synaptic cleft. Here, we show that electrophoretic interactions between AMPA-receptor-mediated excitatory currents and negatively charged glutamate molecules accelerate the clearance of glutamate from the synaptic cleft, speeding-up synaptic responses. This phenomenon is reversed upon depolarization and diminished when intra-cleft electric fields are weakened through a decrease in the AMPA receptor density. In contrast, the kinetics of receptor-mediated currents evoked by direct application of glutamate are voltage-independent, as are synaptic currents mediated by the electrically neutral neurotransmitter GABA. Voltage-dependent temporal tuning of excitatory synaptic responses may thus contribute to signal integration in neural circuits

Wirkungen des Expressiven Schreibens auf depressive Patienten einer Rehabilitationseinrichtung

Das Expressive Schreiben dient zur schriftlichen Verarbeitung und Auseinandersetzung mit Erlebnissen, die als belastend empfunden werden. Im Zusammenhang mit Depressionen, die zu den weltweit häufigsten Krankheitsbildern zählen, konnten in jüngsten Studien erste positive Einflüsse berichtet werden. In dieser Studie sollten die Wirkungen des Expressiven Schreibens auf depressive Patienten einer Rehabilitationseinrichtung untersucht werden. Dazu nahmen 60 Patienten während ihres Rehabilitationsaufenthaltes in Bad Buchau an insgesamt vier Schreibsitzungen, zu je 20 Minuten teil. Es wurden 31 Studienteilnehmer der Testgruppe "Expressives Schreiben" und 29 Studienteilnehmer der Kontrollgruppe "Time Management" zugeteilt. In der Schreibanweisung wurde die Testgruppe "Expressives Schreiben" dazu aufgefordert, ihre innersten Gedanken und Gefühle, sowie ihre belastenden gesundheitlichen Beschwerden aufzuschreiben. Hierbei konnte beobachtet werden, dass das Schreiben einen positiven, aber nicht signifikanten Einfluss auf die Depressionswerte der Probanden, im Gegensatz zur Kontrollgruppe hatte. Mit Hilfe des Positive and Negative Affect Schedules (PANAS) konnte ein marginal signifikanter Rückgang der negativen Affektivität bei stark gedankenunterdrückenden Probanden durch das Expressive Schreiben erfasst werden. Es konnte zudem eine günstige Veränderung des Krankheitskonzepts bei der Testgruppe festgestellt werden. Insbesondere bei der erlebten Kontrolle über die Krankheit zeigten sich signifikante Effekte. Die Effekte werden moderiert von der individuellen Neigung zur Gedankenunterdrückung, denn diejenigen Patienten, die eine stärkere Neigung zur Gedankenunterdrückung (gemessen mit dem White Bear Suppression Inventory) angaben, profitierten mehr vom Expressiven Schreiben als nicht gedankenunterdrückende Probanden

Construction and development of a picosecond UV pump/UV probe spectrometer for combustion diagnostics based on asynchronous optical sampling (ASOPS)

This thesis deals with the construction and development of a picosecond UV pump/UV probe spectrometer for combustion diagnostics based on Asynchronous Optical Sampling (ASOPS). ASOPS avoids many of the difficulties present in conventional pump/probe spectrometers. The instrument utilizes two frequency-double dye lasers which are synchronously pumped by two frequency-doubled, mode-locked Nd:YAG lasers operating at slightly different repetition rates. The difference in repetition rates produces a repetitive relative phase walk-out of the pump and probe pulses which replaces the optical delay line used in conventional pump/probe instruments and thus reduces the data acquisition times from several minutes to microseconds. A description of this process and the instrumentation used in ASOPS is shown along with a general background of current combustion diagnostic methods. Initial combustion studies consisted of visible pump/probe measurements of atomic sodium in an atmospheric pressure flame. With the use of a LiIO\sb3 frequency doubling crystal, average powers of $\sim$20 mW at $\sim$300 nm could be attained with high repetition rate synchronously pumped, mode-locked dye lasers. These high UV powers were attained without the use of complicated amplification techniques normally considered essential for frequency doubling of picosecond lasers. Timing considerations concerning the best choice of beat frequency of the ASOPS technique and its effect on turbulent measurements is considered. UV pump/UV probe measurements of atomic indium in an atmospheric pressure flame are shown making the ASOPS instrument one of only three UV pump/UV probe spectrometers in the world. To improve the ASOPS signal-to-noise ratio, several noise reduction techniques have been implemented. Other noise reduction techniques have been considered and their impact on the ASOPS signal is discussed. Finally, conclusions on the ASOPS technique are presented along with future considerations

Beyond “law school sucks”: Law student views on stress and solutions

Law school is commonly thought to be an intensely stressful graduate program and law students are known to experience high levels of stress and psychiatric distress. A growing body of literature demonstrates that despite entering law school with mental and emotional health profiles comparable to the general population, students experience dramatically increased rates of depression, anxiety, and hostility within the first semester. These elevated levels of distress have been shown to last throughout law school and beyond graduation, and are likely a significant reason for the refrain commonly heard from law students that “law school sucks.” Solutions designed to address law student mental health are wide-ranging and numerous. Yet no published empirical studies have investigated the views of law students on the issue—the issue of how to get beyond “law school sucks.” The present study aims to fill this gap in the literature by presenting results from national survey of first, second, and third year law students on perceptions of law school stress and the utility of programs designed to help law students manage stress (N = 110). It also provides data on resource utilization and explores possible barriers to student use of services. Findings indicate high levels of overall perceived stress across students in all three years of law school. Notable stressors included finding employment and managing the cost of law school, competition for grades, a heavy workload, use of the Socratic method, and a lack of feedback from professors. Resources identified as helpful in managing stress include school gym memberships, on-site psychologists or counselors, and peer mentoring and Academic Support Programs. Wellness classes, yoga, and mindfulness classes received moderate support as well. Together, the results suggest an integrated, holistic approach to law student stress and reflect the current trend of promoting balance in legal education as a means of achieving increased health and wellness for law students

Sensorik und Telemetrie für ein Brennstoffzellenfahrzeug mit Embedded Linux,TCP/IP und WLAN

In dieser Diplomarbeit wird ein Telemetriesystem für die Datenerfassung und drahtlose Überwachung von einem mit einer Wasserstoff Brennstoffzelle betriebenen Fahrzeug entwickelt. Es ist möglich, Daten von einem GPS, einer Brennstoffzelle und Daten von weiteren Sensoren für Temperaturen, Spannungen und Gleichstrom per WLAN zu empfangen. Die Daten können in Realtime von einem Boxenteam mit einer auf LabView basierenden grafischen Oberfläche, ausgewertet werden.This paper presents the development of a telemetrysystem for data acquisition and wireless monitoring of a fuel-cell driven vehicle. It is possible to get data from a GPS, fuel-cell and data from additional Sensors for temperature, voltage and dc-current through WLAN from the vehicle. The data can be monitored in realtime by a team with a LabView based graphical userinterface

Synaptic input from CA3 pyramidal cells to dentate basket cells in rat hippocampus.

1. Excitatory inputs from CA3 pyramidal cells to dentate basket cells were examined using the whole-cell recording technique in neonatal (10-16 days) rat hippocampal slices to characterize this unexpected feedback pathway. 2. Minimal electrical stimulation of the CA3 pyramidal layer evoked in basket cells short latency (5.2 +/- 0.4 ms) glutamate receptor-mediated excitatory postsynaptic currents (EPSCs) with fast rise times (at -70 mV, 0.9 +/- 0.2 ms), fast decay time constants (3.6 +/- 0.6 ms), and small amplitudes (-14 +/- 3.4 pA). Minimal electrical stimulation evoked monosynaptic EPSCs in only 48 +/- 9.2% of the trials suggesting that the CA3 pyramidal cell to basket cell pathway was unreliable. 3. CA3 pyramidal cell layer stimulation did not antidromically or synaptically activate granule cells but did evoke polysynaptic IPSCs in granule cells, suggesting that the net effect of CA3 pyramidal cell firing on the dentate gyrus was granule cell inhibition. 4. Stimulation of the CA3 pyramidal cell layer evoked both monosynaptic and polysynaptic EPSCs in basket cells, which were eliminated by a knife lesion separating CA3 from the dentate gyrus. The latencies of the EPSCs evoked in 0.6 mM extracellular calcium were the same as the earliest latencies of EPSCs in 1.5 mM calcium, suggesting that those EPSCs were monosynaptic. The polysynaptic input was more prominent in the presence of 10 microM bicuculline, implying that inhibitory GABAergic circuits normally limit this feedback from CA3 to basket cells. 5. In recordings from 103 pairs of CA3 pyramidal cells and dentate basket cells from 11 slices, two polysynaptic connections were found that were active only when the presynaptic CA3 pyramidal neuron fired in bursts. No monosynaptic connections between CA3 pyramidal cells and basket cells were identified indicating that connections between the two cell types may be sparse. 6. Raising the external potassium concentration from 3.5 to 8.5 mM, which elicited burst firing in CA3 pyramidal cells, resulted in a barrage of EPSCs and action potentials in basket cells. In contrast, granule cells neither fired action potentials nor exhibited increased EPSC frequency in elevated potassium but instead received a higher frequency of bicuculline-sensitive IPSCs, consistent with interneuron firing. The CA3 pyramidal cell to basket cell monosynaptic pathway exhibited paired-pulse facilitation as manifested by an increased probability of release, which supports the idea that basket cells were better activated by short trains of action potentials than by single inputs.(ABSTRACT TRUNCATED AT 400 WORDS

Subjektive Krankheitskonzepte bei depressiven Störungen: Längsschnittstudie einer rehabilitativen Maßnahme

Depressive Störungen sind ein weit verbreitetes und oft chronisches Gesundheitsproblem mit erheblichem Leiden des Individuums und hohen Gesundheitskosten. Die subjektiven Wahrnehmungen einer solchen Erkrankung korrelieren mit deren Bewältigung. Dies kann insbesondere für depressive Störungen angenommen werden, da bei Depressionen die dysfunktionalen kognitiven Bewertungsprozesse sowohl ätiologisch relevant sind als auch die Krankheitsbewältigung ungünstig beeinflussen. Diese Studie hat zum Ziel, Zusammenhänge zwischen Dimensionen der Krankheitskonzepte von Patientinnen und Patienten, der depressiven Symptomatik und positivem Affekt zu untersuchen. Dazu wurden 60 Patientinnen und Patienten einer stationären psychosomatischen Rehabilitationsmaßnahme sowohl im Quer- als auch im Längsschnitt bis zur dreimonatigen Katamnese nach Entlassung befragt. Die Studienteilnehmer wurden weiterhin randomisiert einer Expressiven Schreib- oder einer Kontrollbedingung zugeteilt, um die Effekte dieser Minimalintervention als adjunkte Maßnahme zu untersuchen. Die Ergebnisse zeigen, dass die Wahrnehmung des zeitlichen Verlaufs und des Schwergrads der Depression sowie die emotionalen Repräsentationen der eigenen Erkrankung mit vermehrten depressiven Symptomen assoziiert sind. Im Längsschnitt zeigt sich, dass die Ausprägung kontrollbezogener subjektiver Krankheitskonzepte mit unterschiedlichen Verläufen der depressiven Symptomatik und des Wohlbefindens über einen Zeitraum von 3 Monaten nach Beendigung des stationären Aufenthalts im Zusammenhang stehen. Die subjektiv erlebte Kohärenz des Krankheitskonzepts war nur mit dem Wohlbefinden, aber nicht mit Depression verbunden. Expressives Schreiben konnte in dieser kleinen Gruppe zusätzlich zum stationären Aufenthalt zwar keine signifikanten Verbesserungen erzielen, jedoch zeigt sich, dass Personen mit einer stark ausgeprägten Neigung zu emotionalen Repräsentationen tendenziell mehr vom Schreiben profitieren und dass sich dieser Effekt über die Zeit zu verstärken scheint. Schlüsselwörter: Krankheitskonzept, Depression, Expressives Schreibe