1,433 research outputs found
Visual Expectations in Infants: Evaluating the Gaze-Direction Model
Schlesinger (in press) recently proposed a model of
eye movements as a tool for investigating infantsâ
visual expectations. In the present study, this gaze-direction
model was evaluated by (a) generating a set
of predictions concerning how infants distribute their
attention during possible and impossible events, and
(b) testing these predictions in a replication of
Baillargeonâs "car study" (1986; Baillargeon &
DeVos, 1991). We find that the model successfully
predicts general features of infantsâ gaze direction,
but not specific differences obtained during the
possible and impossible events. The implications of
these results for infant cognition research and theory
are discussed
Photoemission study of the SiOâconversion mechanism to magnesium silicate
The objective of this work is to investigate interface chemistries which minimize the interfacial silicon oxide transition region at Si/high-k dielectric interfaces. We report on the mechanism by which a silicon native oxide layer is converted into magnesium silicate. The deposition of metal Mg onto a SiO native oxide surface resulted in the formation of a magnesium silicide in addition to substochiometric silicon oxides and a significant decrease in the oxidised silicon signal. Annealing to 300â°C resulted in the decomposition of the magnesium silicide, oxidation of the Mg, and the desorption of excess metallic Mg. Subsequent annealing to 500â°C resulted in converting the SiO2 into magnesium silicate. The results suggest that the decomposition of the Mg silicide in the presence of the residual native oxide facilitates silicate formation at 500â°C. Due to the reported thermal stability of Mg silicate it is suggested that this process may be beneficial in modifying the interface characteristics of the Si/high-k dielectric interface which has potentially significant implications for future semiconductor device generations
Philadelphia's Councilmanic Prerogative: How It Works and Why It Matters
This report examines the Philadelphia legislative practice known as "councilmanic prerogative," through which individual City Council members make nearly all of the land use decisions in their jurisdictions. This report on councilmanic prerogative is grounded in extensive analysis of city records and interviews with dozens of government officials, developers, political figures, academics, and community advocates. It is the first independent examination of the practice in the city
Life Among the Machines: James Joyce\u27s Ulysses and Early Twentieth-Century Technology
This project investigates the cultural impact of the various technological innovations that appeared around the turn of the twentieth century, and how modernism contends with the increasing presence of technology in everyday life. It focuses on the work of James Joyce, whose attitudes toward technology differ significantly from many of his contemporaries, and on his novel Ulysses, which takes place in metropolitan Dublin and features many of the everyday technologies of the early twentieth century.
The first chapter examines the relationship between technology and the vitalist theories of Henri Bergson and Hans Driesch, arguing that the popularity these theories enjoyed arose from anxieties about the eroding barrier between the human and the machine. The principal characters in Joyceâs novel stand on opposite sides of the vitalist debate.
The second chapter describes how the gramophone troubled traditional associations between the voice and the living breath as the guarantor of the presence of an authentic, living speaker. It looks at how various inventions provided metaphors for, and promoted belief in, supernatural phenomena like telepathy and metapersonal memory, arguing that Joyceâs understanding of the âuncannyâ side of technology leads him to satirize such enthusiasms in Ulysses.
The third chapter opens by considering the gendering of mass culture as opposed to high art, and looks at the role pornography plays both in Ulysses and in the reception of Joyceâs novel. It investigates how mechanical reproduction complicated the traditional associations between women, nature, and technology, and how these complications prompted a turn toward more physical and vitalistic conceptions of masculinity
Growth and Characterisation studies of MgO and Mg silicate dielectric layers on Si and InP surfaces
This thesis investigates the suitability of magnesium oxide (MgO) and magnesium silicate as possible high-k dielectric materials on both silicon and indium phosphide (InP) surfaces. Given that the emphasis of this study was controlling the semiconductor/high-k interface formation, the principle experimental technique used in these studies was x-ray photoelectron spectroscopy (XPS), however, additional techniques such as atomic force microscopy (AFM) and electrical characterisation have also been employed. XPS studies have shown that exposure to ambient conditions results in the rapid formation of magnesium hydroxide and carbide species on the surface of MgO thin films. In order to prevent the detrimental affect of ambient exposure MgO/Si MOS devices were fabricated using an optimised metallisation procedure, called the FUSI process. Electrical characterisation of FUSI devices show low (< 1012 cm-2) interfacial state densities, and allowed the dielectric constant of MgO (~10) to be calculated. Transmission electron microscopy (TEM) and high resolution synchrotron based XPS have identified the presence of thin (< 1 nm) amorphous magnesium silicate layers at the MgO/Si interface. Studies show no evidence for the formation of SiO2 upon MgO deposition with Mg silicate forming preferentially following MgO deposition onto both H-terminated and oxidised Si surfaces, and also following high temperature annealing. The mechanism by which Si oxide surfaces can be converted into Mg silicate has also been investigated. It has been shown that room temperature deposition of metallic Mg results in the formation of Mg silicide which decomposes during UHV annealing at 300 °C. Subsequent annealing to 500 °C results in the complete conversion of SiO2 to Mg silicate. As Mg silicide growth has been shown to be a vital intermediate step to silicate formation, the growth and stability of Mg silicide thin films on Si has also been investigated. InP studies have focused on the preparation of oxide free, chemically stable surfaces prior to MgO deposition. The effectiveness of different chemical wet etch preparation procedures are compared to that of in-situ atomic hydrogen cleaning based on both the removal of oxide species and the chemical stability of the cleaned surface. The deposition of Si and Mg silicate interfacial control layers (ICL) onto InP has been shown to effectively passivate the InP surface, inhibiting the growth of In and P oxide species upon MgO deposition and subsequent 500 °C annealing
Constructing a spectral photometer for the study of light pollution
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaf 22).In this paper, I describe a method and apparatus for carrying out a systematic spectroscopic mapping I([lambda], z, [Phi]) of the night sky, as proposed by Stefano Rosoni. Once completed, this method should prove to be simple and effective, while the SLR film camera spectral photometer constructed and described within should prove to be inexpensive and easily reproducible. The spectral photometer is simply a single slit diffraction apparatus mounted to the rear of a telescope. The resulting interference pattern is recorded as an image projected on the film inside the camera. In order to correlate the image recorded on the film to a spectrum containing information about the intensity and wavelength of the light pollution, the photographs were scanned into digital format and analyzed by a series of computer programs. While a film spectral photometer is in itself, nothing new, the computer algorithm used to extrapolate film response curves was developed by Paul Debeveck and Jitendra Malik for use in computer graphics. I apply their algorithm to the problem of calibration of a spectral photometer and bypass the myriad of tedious and time consuming calibrations which make film cameras almost more trouble than they are worth. Problems from the unsuccessful first prototype are discussed, as well as suggested improvements for further versions PACS numbers: 95.45. + i, 95.55.Qf, 95.75.P
Has The âWar On Terrorâ Put Due Process On The Stand? Why The ECJ's Approach In Kadi II Should Be Used Across The Atlantic
The European Court of Justice (ECJ) struck a balance between due process rights and national security in the Kadi II case. Applying the ECJâs analysis to a case recently decided by the D.C. District Court â the Zaidan case â illustrates that a more rights-protective approach can be attained in US courts too. First, this article will explore due process in Europe via the four different versions of the Kadi case. Then, it will take an in-depth look at the Zaidan case. The article concludes by arguing that the D.C. Circuit Court of Appeals should adopt a stance on due process similar to that taken by the ECJ in the Kadi II case â which served to uphold the rule of law in Europe by making the actions of public officials reviewable before EU courts in the counter-terrorism context. By exercising a more âmuscularâ attitude towards the other branches of governmentâs counter-terrorism measures, the US judiciary might use this case to start a new line of precedent distinct from prior US cases with respect to US citizensâ constitutional rights in the post 9/11 counter-terrorism paradigm.The European Court of Justice (ECJ) struck a balance between due process rights and national security in the Kadi II case. Applying the ECJâs analysis to a case recently decided by the D.C. District Court â the Zaidan case â illustrates that a more rights-protective approach can be attained in US courts too. First, this article will explore due process in Europe via the four different versions of the Kadi case. Then, it will take an in-depth look at the Zaidan case. The article concludes by arguing that the D.C. Circuit Court of Appeals should adopt a stance on due process similar to that taken by the ECJ in the Kadi II case â which served to uphold the rule of law in Europe by making the actions of public officials reviewable before EU courts in the counter-terrorism context. By exercising a more âmuscularâ attitude towards the other branches of governmentâs counter-terrorism measures, the US judiciary might use this case to start a new line of precedent distinct from prior US cases with respect to US citizensâ constitutional rights in the post 9/11 counter-terrorism paradigm
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An investigation of the physical parameters of young stellar objects
textStudies of the temporal evolution of young stars and their associated properties rely upon the ability of astronomers to determine ages and masses of objects in different evolutionary states. The best method for determining the age and mass of a young stellar object is to place the object on the Hertzsprung-Russell (HR) diagram and to compare to theoretical evolutionary tracks. Accurate ages allow the investigation of the temporal evolution of properties associated with stellar youth (accretion rates, X-ray activity, circumstellar excess, etc...). One property intimately linked with stellar youth is the presence (or absence) of an optically thick primordial circumstellar disk. Objects in "young" star forming regions are more likely to show evidence for a disk than objects in "older" clusters. Within a single cluster, the picture is not as clear. There exist objects in very young clusters (~1 Myr) which show no evidence for circumstellar disks, and there exist objects in very old clusters (~10 Myr), which show evidence for robust disks, suggesting a variable other than stellar age is driving the evolution of the disks. To investigate whether these outliers are due to age spreads, initial conditions, or simply appear anomalous due to erroneous age determinations, we must determine better placements in the HR diagram by carefully transforming observable quantities (spectral type and apparent magnitude) into the quantities necessary for comparison evolutionary models (effective temperature and luminosity). In the Ophiuchus star forming region, I investigate whether or not objects with disks are younger than disk-less objects. I find no difference in the ages of the two populations, but the systematic and random uncertainties are large enough to mask all but the largest age differences. In the hope of better determining the physical parameters of young stellar objects, I embark on a spectral synthesis campaign to produce comparison synthetic spectra which account for the effects of magnetic fields. This requires the modification of the MOOG spectral synthesis program to handle the full Stokes vector treatment for polarized radiation through a magnetized medium. I create a grid of synthetic spectra covering ranges in effective temperature, surface gravity, and average magnetic field strength relevant for studies of young stellar objects, and develop a Chi-squared minimization routine to determine the best fit synthetic spectrum for a given observed spectrum at an arbitrary resolving power. This grid of synthetic spectra will be an invaluable complement to future near infrared, large band-pass, high-resolving power spectrographs (i.e. IGRINS). In addition to these observational and theoretical attempts to reduce systematic errors, I also helped to develop a suite of silicon and KRS-5 grisms for use in the FORCAST instrument, a mid infrared camera on the SOFIA telescope. These grisms will afford the imaging instrument a mid infrared spectroscopic capability at wavelengths normally inaccessible from the ground. I also report on my work to help write FG Widget, the quick-look reduction software package developed to support grism observations.Astronom
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