Ab-initio-MO-Studie Methyl- und Phenyl-substituierter Allenyl-Kationen

An den Methyl- und Phenyl-substituierten Allenyl-Kationen 3 - 12 (Tab. 1) wurden ab-initio-MO-Berechnungen unter Verwendung des STO-3G Basissatzes durchgeführt. Die berechneten Bindungslängen und Ladungsverteilungen zeigen Delokalisierung der positiven Ladung an, wie in Formel 1 gezeigt. Mit Hilfe isodesmischer Reaktionen werden Stabilisierungsenergien von Substituenten in 1- und 3-Position ermittelt. Diese Werte ermöglichen in Kombination mit der experimentell bekannten Bildungswärme des Stammkörpers 2 die Bestimmung von H sämtlicher Allenyl-Kationen 3 - 12. Der Vergleich dieser Daten mit einigen experimentell bestimmten Bildungswärmen zeigt Übereinstimmung innerhalb von 2 kcal/mol. Es werden Voraussagen für das Reaktionsverhalten gegenüber n-Nucleophilen und -Systemen gemacht

Recovered Voices: Fairy Tales and the Reading Child

In the traditional literature classroom, students are typically guided through literature discussions by their teacher, and then assessed on how well they can reiterate predetermined interpretations of what they have read. Within these literature discussions, classroom talk creates a power structure, with the teacher as owner of knowledge, and students as those lacking this knowledge. This study seeks to upset this power structure, by removing the guiding force of the teacher in literature discussions, as well as the assessments which follow. In a further effort to allow for a literature discussion which is genuinely for students, the genre of fairy tales will serve as the selected literature. The field of curriculum studies is concerned with recognizing contexts, and working to understand how these many contexts contribute to the education of children. Located within the field of literary criticism, interpretive communities have been selected as a methodology which recognizes a way of looking at students looking at literature through unique perspectives. By allowing students the opportunity to experience literature without the attached traditional activities imposed on them, it is the intent that a novel discourse will be created; one that recognizes and values the interpretation of the child

Childhood Obesity: Prevention & Intervention

Childhood obesity rates have skyrocketed in the recent years. These trends are alarming since childhood obesity has been linked to numerous health conditions, socioemotional consequences, and academic consequences. This project examines the factors that have been associated with childhood obesity and the consequences of being obese or overweight for children. This project also presents lifestyle changes that parents can make to reduce the likelihood of their children becoming overweight or obese

PACE Technical Report Series, Volume 5: Mission Formulation Studies

This chapter summarizes the mission architecture for the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission, ranging from its scientific rationale to the history of its realized conception to itspresent-day organization and management. This volume in the PACE Technical Report series focuses ontrade studies that informed the formulation of the mission in its pre-Phase A (2014-2016; pre-formulation:define a viable and affordable concept) and Phase A (2016-2017; concept and technology development).With that in mind, this chapter serves to introduce the mission by providing: a brief summary of thescience drivers for the mission; a history of the direction of the mission to NASA's Goddard Space Flight Center (GSFC); a synopsis of the mission's and instruments' management and development structures; and a brief description of the primary components and elements that form the foundation ofthe mission, encompassing the major mission segments (space, ground, and science data processing) and their roles in integration, testing, and operations

Letter from Benson Lossing to Dexter Chase, December 14, 1871

A reproduction of the original and typed transcription of the letter from Benson Lossing to Dexter Chase, December 14, 1871

A Narrative Review on Central Neuraxial Blocks and Direct Oral Anticoagulants

Objective In numerous studies aspiring to clarify when to discontinue direct oral anticoagulants (DOAC) before central nerve blocks (CNB), information about the technique: spinal, epidural, indwelling catheter, multiple attempts, ‘bloody tap’: is incomplete. This creates difficulty making evidence-based recommendations regarding the safest time frame between the last dose of DOAC and CNB to avoid spinal haematoma. Current guidelines and recommendations are based mainly on pharmacokinetic predictions of the time taken to reach low residual plasma levels of DOAC. Empirical research is almost impossible since the risk of haemorrhagic complication is very low.Design A structured search of publications on DOAC and CNB was performed on Pubmed.Results Accurate plasma level measurements by mass spectrometry are usually not available. Indirect calibrated anti-Xa and IIa methods are unreliable at DOAC levels <30 ng/ml. DOAC plasma levels that are safe for CNB are presently unknown.Conclusion We recommend at least 5 half-lives (T1/2) after the last dose of DOAC before performing CNB, as there is wide interindividual variation in T1/2 and thereby residual plasma concentrations. The maximal residual DOAC plasma level should then be below 3% of therapeutic levels. Such long interruption times prior to surgery are problematic in patients at high risk of arterial and venous thromboembolism, it may be safer to withhold DOAC for 4 half-lives and conduct surgery without CNB. Bridging with low molecular weight heparin (LMWH) may increase the risk of spinal haematoma with CNB

Fenomeno erosivo in corrispondenza di pile di ponte allocate in prossimità delle sponde.

La tesi presenta un analisi sperimentale riguardo gli effetti della posizione delle pile dei ponti lungo la sezione fluviale sia in presenza di materiale flottante (debris) che in sua assenza e la ricerca dell'equazione che descriva l'evoluzione temporale dello scavo. La tesi è articolata in cinque capitoli: -nel primo capitolo viene descritto lo stato attuale delle conoscenze riguardo l'erosione localizzata presso le pile dei ponti sia in presenza che in assenza di materiale flottante; -il secondo capitolo descrive l'apparato sperimentale e le modalità d'esecuzione delle prove; -il terzo capitolo tratta l'elaborazione dei dati, la ricerca delle equazioni e la verifica delle stesse; -il quarto capitolo confronta, in maniera qualitativa, la morfologia del fondo al termine deli vari test; -il quinto capitolo chiude il lavoro e riassume le conclusioni

Measuring changes in Schlemm’s canal and trabecular meshwork in different accommodation states in myopia children: an observational study

Abstract Purpose: Studies were designed to evaluate changes in the size of the Schlemm's Canal (SC) and trabecular meshwork(TM) during accommodation stimuli and cycloplegia states in myopic children. Methods: 34 children were enrolled. A -6D accommodation stimulus was achieved by looking at an optotype through a mirror. Cycloplegia state was induced with 1% tropicamide. Two states were confirmed by measuring the central lens thickness（CLT）, the anterior chamber depth and the pupil diameter. The size of the Schlemm's Canal (SC) and Trabecular Meshwork(TM) was measured using swept-source optical coherence tomography. And the associations between the change of the SC and the CLT were analyzed. Results: When compared with the relaxation state, under -6D accommodation stimuli, the size of SC increased significantly: the SC area (SCA) amplified from 6371±2517μm2 to 7824±2727 μm2; the SC length (SCL) from 249±10 μm to 295±12 μm, and SC width (SCW) from 27±9 μm to 31±8 μm. Under cycloplegia state, the SCA reduced to 5009±2028 μm2; the SCL to 212±μm and the SCW to 22±5 μm. In addition, the changed areas of SCA (r=0. 35; P=0.0007), SCL (r=0. 251; P=0.0172), and SCW (r=0. 253; P=0.016) were significantly correlated with the change in CLT. However, the size of TM did not change substantially when compared with the relaxation state. Only the TM length (TML) increased from 562±45μm to 587±47μm after -6D accommodation stimulus. Conclusion: SC size enlarges after -6D accommodation stimuli and shrinks under cycloplegia. However, for TM, only the TM length increase under accommodation stimulus state. KEYWORDS: Schlemm’s Canal, Trabecular Meshwork, accommodatio