Knowledge from below

This thesis elucidates artistic research on the programmed world and its brutal machines. It describes a practice that hones a deviant worldview while confronting ubiquity. Applying web scraping as an investigative tool and a filmmaking methodology, I work with archives of traffic images. The pictures, portraying the smart city through its scattered, self-surveilling eyes, offer a cinematic mirror of reality. I select, annotate, and edit sequences to expose agents of administrative violence. Rejecting a vision of progress that rests on exploitation, I aim to destabilize readings of surveillance and policing as beacons of safety. My work proposes models for seeing and knowing from below

Arbuscular mycorrhizal fungi associated with five tallgrass prairie forbs

Do host plant species, in particular prairie forbs, associate with the same arbuscular mycorrhizal (AM) fungal species at various locations within the Midwestern prairie states? And, do different plant species within a site have similar AM fungal communities, or is there a high degree of host-specificity? If prairie forbs do associate with similar fungal species at various locations or are host-specific, we may be able to apply that knowledge to prairie reconstructions and increase the establishment of forb species. Well-established prairie seed production plots of three commercial nurseries in Iowa, Wisconsin, and Minnesota, in the tallgrass prairie region of the Midwestern U.S., were sampled in October 2004. Soil cores for analysis of AM spores, root samples for determination of AM colonization, and soil samples were collected from monospecific plots of five prairie forbs, Heuchera richardsonii R. (Alumroot), Veronicastrum virginicum L. (Culver\u27s root), Silphiumperfoliatum L. (Cup plant), Ratibida pinnata (Vent.) (Yellow/Gray-headed Coneflower), and Hypericum pyramidatum L. (St. John\u27s Wort). Spores of AM fungi were extracted from the soil samples and were identified by morphological characteristics. Over all three sites and all plant species, spores of 35 AM fungal species were found in the soil cores, representing six genera. Plant species all showed evidence of mycorrhizal infection and roots were at least 34% colonized by AM fungi. There were no significant relationships between the number of fungal species in a plot and the soil pH or content of P, NH₄, or NO₃⁻. Overall, 43% of fungal species found were ubiquitous and 17% were exclusive to a particular site. Over all sites, yellow coneflower had the highest mean fungal species richness (26.3), significantly higher (p\u3c.005) than Culver\u27s root (19.3), which had the lowest richness. Over all plant species, fungal community similarity between pairs of sites was on average 51.3% (using Sorenson\u27s index). Fungal community similarity between pairs of sites for any one plant species ranged from 80 to 96%, with a mean of 86.3%. Similarity between pairs of plant species within any one site varied from 69 to 93%, with a mean of 85.5%. Fungal communities were very similar both within individual prairie forb species regardless of field site and within a field site regardless of forb species. There were very few species found exclusively with one plant species or at one site; most of the fungi were generalists and exhibited little host-specificity, and all plant species had a substantial number of fungal associates

Prone sleeping and SUDEP risk: The dynamics of body positions in nonfatal convulsive seizures

BACKGROUND: Most victims of sudden unexpected death in epilepsy (SUDEP) are found prone with signs suggestive of an unwitnessed convulsive seizure (CS). Prone sleeping has been proposed as a risk factor for SUDEP. Little is known, however, about the change of body position during the course of CSs. METHODS: We retrospectively reviewed video-EEG data and assessed body positions during the course of CSs, until there was a physical interaction by nursing staff with the subject. RESULTS: We identified 180 CSs in 90 individuals. In 16 of the 180 CSs (9%), the subject started in or turned to the prone position. Of the seven CSs that started in the prone position, three turned to a lateral position during the CS. In 13 CSs, the subject was in prone position at time of nursing intervention; nine (69%) of these started in a nonprone position. DISCUSSION: Our data suggest that the prone position occurs infrequently in closely supervised nonfatal CSs, a notable contrast to the number of victims of SUDEP found prone. Whether prone sleeping prior to CSs increases SUDEP risk, however, remains speculative, as body position during the course of a CS appeared to be dynamic

Late breakdown behaviour of 72.5 kV vacuum interrupters during capacitive switching with a synthetic test method

The interruption of capacitive currents involves a demanding dielectric stress for high voltage vacuum interrupters. Dielectric breakdowns up to several hundreds of milliseconds after current interruption are possible, which may result in harmful voltage escalations. Additionally, high inrush currents prestress the vacuum interrupter especially during the energisation of capacitor banks. A synthetic test method is applied to study the late breakdown behaviour of vacuum interrupters of 72.5 kV rated voltage during capacitive switching. The first part of this work focuses on factorial experiments that are applied to determine the influence of different test circuit parameters on the breakdown behaviour in an efficient way. The results confirm the significant impact of inrush currents on the breakdown rate. However, a relevant effect of the other tested parameters, e.g. breaking current and arcing time, cannot be ascertained for the investigated range. In the second part of this work measured pre-breakdown phenomena are presented and discussed. While field emission currents are measured with a commonly applied sense resistor, the detection of charged microparticles is conducted by utilising a partial discharge measurement technique. With a contact stroke set to 38 mm field emission currents occur only rarely and only during the beginning of the recovery voltage with preceding late contact separation, when the full contact gap has not yet been established. For a reduced contact stroke of 20 mm high field emission currents can be present for long periods of time with magnitudes up to several tens of milliamperes. The phenomenon of self-limiting current pulses, often referred to as microdischarges, has also been observed repeatedly. Field emission currents and microdischarges are more likely to appear after the vacuum interrupter is stressed by an inrush current. However, the majority of breaking tests with late breakdowns include neither significant preceding field emission current nor microdischarges. Moreover, the mere presence of the highest field emission currents does not necessarily result in a disruptive discharge. This result supports the hypothesis that field emission at larger contact gaps has a negligible influence on the late breakdown behaviour. In the case of the microparticle detection measurement, a recurring current pulse pattern was detected that is likely to be linked to microparticles impacting with the contact surface. However, no correlation can be drawn between the frequency of occurrence of this pulse pattern and the occurrence of late breakdowns. Therefore, it is concluded that the breakdown process is not triggered by multiple microparticle collisions but rather by a singular event supplying sufficient energy for the release of electrons and gaseous matter for the fast development of dielectric breakdown inside the vacuum interrupter

A Professional Development Program to Improve Math Skills Among Preschool Children in Head Start

The purpose of this study was to examine the effect of providing early educators professional development experiences and activities to improve the mathematical skills of preschool children in Head Start around four domains of mathematics. Because of the need to provide necessary mathematical experiences to young children to improve their early understanding and skills and provide the foundation for future success in mathematics, we provided the treatment group of early educators with professional development and center-based activities to promote four critical areas in mathematics. By randomly selecting Head Start centers to participate as the treatment group or control group, we were able to examine the effects of the professional development and set of activities on preschool children’s knowledge over a six-month period. We found children in the treatment group were more fluent and flexible with number concepts, were better at solving contextual problems, and had better measurement and spatial abilities than children in the control group

How coupled slow oscillations, spindles and ripples coordinate neuronal processing and communication during human sleep

Learning and plasticity rely on fine-tuned regulation of neuronal circuits during offline periods. An unresolved puzzle is how the sleeping brain, in the absence of external stimulation or conscious effort, coordinates neuronal firing rates (FRs) and communication within and across circuits to support synaptic and systems consolidation. Using intracranial electroencephalography combined with multiunit activity recordings from the human hippocampus and surrounding medial temporal lobe (MTL) areas, we show that, governed by slow oscillation (SO) up-states, sleep spindles set a timeframe for ripples to occur. This sequential coupling leads to a stepwise increase in (1) neuronal FRs, (2) short-latency cross-correlations among local neuronal assemblies and (3) cross-regional MTL interactions. Triggered by SOs and spindles, ripples thus establish optimal conditions for spike-timing-dependent plasticity and systems consolidation. These results unveil how the sequential coupling of specific sleep rhythms orchestrates neuronal processing and communication during human sleep

RM methods for airline fare family structures

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2013.This electronic version was submitted and approved by the author's academic department as part of an electronic thesis pilot project. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from department-submitted PDF version of thesisIncludes bibliographical references (p. 119-121).The rapid growth of low cost carriers forced many legacy airlines to simplify their fare structures and develop new pricing strategies to remain competitive. The strategy of branded fares, or "fare families", is an increasingly popular approach for airlines to differentiate their products and services from other competitors. This thesis provides a comprehensive overview of revenue management (RM) forecasting and optimization methods developed specifically for fare family structures. These methods, collectively termed Q-Forecasting for Fare Families (QFF), provide airlines with the capability to manage branded fares from a RM perspective. The QFF methods are all constructed based on the assumed fare family passenger choice model, which accounts for both willingness-to-pay estimates as well as family preference. Each formulation makes underlying assumptions regarding passenger sell-up and buy-across. The Passenger Origin Destination Simulator is used to test and compare the performance of each QFF formulation in a dual airline competitive environment, both with leg-based RM controls as well as network RM controls. The results from the simulations indicate that substantial gains in both revenue and yield over traditional RM methods can be achieved with appropriate RM in a fare family structure. Specifically, while Hybrid Forecasting (with leg RM controls) generates a 4.0% increase in revenue over Standard Forecasting, QFF is shown to increase revenues by more than 12.5%. The benefits of QFF are greater with network RM controls, with potential revenue increases of nearly 14.0% (over Standard Forecasting). The positive results obtained with each QFF formulation are dependent upon an appropriate estimate for passenger sell-up and family preference. Consequently, this research also illustrates the importance of the estimate for passenger willingness-to- pay and its relationship to forecasting and optimization in airline RM.by Vincent B. Surges.S.M

Regulated expression of HCN channels and cAMP levels shape the properties of the h current in developing rat hippocampus.

The hyperpolarization-activated current (I(h)) contributes to intrinsic properties and network responses of neurons. Its biophysical properties depend on the expression profiles of the underlying hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels and the presence of cyclic AMP (cAMP) that potently and differentially modulates I(h) conducted by HCN1, HCN2 and/or HCN4. Here, we studied the properties of I(h) in hippocampal CA1 pyramidal cells, the developmental evolution of the HCN-subunit isoforms that contribute to this current, and their interplay with age-dependent free cAMP concentrations, using electrophysiological, molecular and biochemical methods. I(h) amplitude increased progressively during the first four postnatal weeks, consistent with the observed overall increased expression of HCN channels. Activation kinetics of the current accelerated during this period, consonant with the quantitative reduction of mRNA and protein expression of the slow-kinetics HCN4 isoform and increased levels of HCN1. The sensitivity of I(h) to cAMP, and the contribution of the slow component to the overall I(h), decreased with age. These are likely a result of the developmentally regulated transition of the complement of HCN channel isoforms from cAMP sensitive to relatively cAMP insensitive. Thus, although hippocampal cAMP concentrations increased over twofold during the developmental period studied, the coordinated changes in expression of three HCN channel isoforms resulted in reduced effects of this signalling molecule on neuronal h currents