9,888 research outputs found
Asian-Americans and the Internet
Presents findings from a survey conducted between March and December 2001, to document the use of the Internet by English speaking Asian Americans. Looks at differences in online use by age, gender, education, and economic status
A study of the relationship between certain tests and grades at Boston University School of Education
Thesis (Ed.M.)--Boston Universit
The DRIFT Directional Dark Matter Detector and First Studies of the Head-Tail Effect
Measurement of the direction of the elastic nuclear recoil track and
ionization charge distribution along it, gives unique possibility for
unambiguous detection of the dark matter WIMP particle. Within current
radiation detection technologies only Time Projection Chambers filled with low
pressure gas are capable of such measurement. Due to the character of the
electronic and nuclear stopping powers of low energy nuclear recoils in the
gas, an asymmetric ionization charge distribution along their tracks may be
expected. Preliminary study of this effect, called Head-Tail, has been carried
out here using the SRIM simulation program for Carbon and Sulfur in 40 Torr
carbon disulfide, as relevant to the DRIFT detector. Investigations were
focused on ion tracks projected onto the axis of the initial direction of
motion in the energy range between 10 and 400 keV. Results indicate the likely
existence of an asymmetry influenced by two competing effects: the nature of
the stopping power and range straggling. The former tends to result in the Tail
being greater than the Head and the latter the reverse. It has been found that
for projected tracks the mean position of the ionization charge flows from
'head' to 'tail' with the magnitude depending on the ion type and its energy.Comment: To appear in the proceedings of Dark 2007 Sixth International
Heidelberg conference on "Dark Matter in Astro & Particle Physics", Sydney,
Australia 24th-28th September 200
Reduction of Coincident Photomultiplier Noise Relevant to Astroparticle Physics Experiment
In low background and low threshold particle astrophysics experiments using
observation of Cherenkov or scintillation light it is common to use pairs or
arrays of photomultipliers operated in coincidence. In such circumstances, for
instance in dark matter and neutrino experiments, unexpected PMT noise events
have been observed, probably arising from generation of light from one PMT
being detected by one or more other PMTs. We describe here experimental
investigation of such coincident noise events and development of new techniques
to remove them using novel pulse shape discrimination procedures. When applied
to data from a low background NaI detector with facing PMTs the new procedures
are found to improve noise rejection by a factor of 20 over conventional
techniques, with significantly reduced loss of signal events.Comment: Submitted to NIM
The Transformation Process of Fathers of Children with Disabilities: An Exploratory Case Study
While the vital role that fathers play in the development of their children is emphasized in recent literature, the majority of research relative to child development focuses on mothers. This imbalance is even more evident relative to research with parents of children with disabilities, leaving human service providers with few evidence based practices for appropriately addressing the needs of fathers raising children with disabilities. Research suggests that having a child with a disability, while challenging, can also have a significant positive impact on the family system and potentially offer a transformational experience for the parent. Guided by a theoretical model of transformational outcomes, the purpose of this qualitative case study was to investigate how two veteran fathers of children with disabilities describe their transformative process. Using qualitative inquiry methods, the fathers’ were interviewed and their narratives were transcribed and analyzed to discover emerging themes. Findings indicated that laughter was a prominent emotion throughout the narrative and that the fathers used both positive and negative descriptors to define their experiences. Implications of these findings for human service professionals supporting families of children with disabilities are discussed. Attending to the unique needs of fathers can improve the overall functionality of the family system
The Dot-com Meltdown and the Web
Presents findings from a survey conducted between August and September 2001. Looks at how the collapse of the dot-com economy has had tangible effects on personal lives, and how online Americans have made quick adjustments to the changing Web environment
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Non-invasive investigations of a wall painting using optical coherence tomography and hyperspectral imaging
Multispectral and hyperspectral imaging are efficient methods of measuring spectral reflectance at high spatial resolution. This non-invasive technique has been applied to the imaging of paintings over the last 20 years. PRISMS (Portable Remote Imaging System for Multispectral Scanning) was designed specifically for imaging wall paintings. Optical Coherence Tomography (OCT) is a low coherence interferometric technique capable of fast non-invasive imaging of subsurface microstructure. This paper shows the first application of in situ OCT imaging of a wall painting. The combination of PRISMS and OCT gives information on the varnish and paint layer structure, pigment identification, the state of degradation of the paint and varnish layers and informing curators on the painting schemes and techniques
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