Biomedical subjects

Gregory Williams

Publications and source records attributed to Gregory Williams.

3 recordsLinked to original sources

PubMed2004

Follow-up after inpatient psychiatric hospitalization with partial control of the system responsiveness variable.

One of the most significant predictors of prompt rehospitalization following psychiatric hospital discharge is missing follow-up out-patient appointments. Previous studies have suggested that system responsiveness accounted for much of the variance in predicting compliance with aftercare. Collaborations established at our institution allowed us to partially control this variable, opening the way to explore other obstacles to aftercare. All severely mentally ill subjects discharged from our hospital are provided follow-up appointments within two weeks. We retrospectively evaluated compliance with aftercare appointment and investigated factors that were associated with compliance. Eighty-one subjects were evaluated. Twenty-seven (33.8 %) did not attend their first follow-up appointment. Subjects with a primary substance-related syndrome were the most likely to miss their appointment (83.3%, chi 2 = 17.02, p = .0045), as were uninsured patients (51.6%, chi 2 = 8.79, p = .003). There was a trend for individuals not previously involved with their aftercare providers to miss their appointment (48.9%, chi 2 = 3.35, p = .067). Despite partial control of the system responsiveness variable, compliance with aftercare was suboptimal. This was due to a combination of client vulnerability variables and uncontrollable system responsiveness factors.

Adolescent↗

PubMed2004

A DNA Motif Lexicon: cataloguing and annotating sequences.

The rapid proliferation of genomic DNA sequences has created a significant need for software that can both focus on relatively small areas (such as within genes or promoters) and provide wide-zoom views of patterns across entire genomes. We present our DNA Motif Lexicon that enables users to perform genome-wide searches for motifs of interest and create customizable results pages, where results differ in the degree and extent of annotation. Searching for a particular motif is akin to a word search in a natural language; our motif lexicon speaks to this new time when we will increasingly rely upon DNA dictionaries that offer rich types of annotation. Indeed, the concept of "lexomics", introduced in this paper may be appropriate to the types of meta-analyses appropriate to the deciphering of regulatory information. Currently supporting five genomes, our web-based lexicon allows users to look up motifs of interest and build user-defined result pages to include the following: (1) all base pair locations where a motif is found with links to further search the "neighborhoods" near each of these locations; whether each location of the motif is genic (within) a gene, intergenic, or a bridging sequence (overlapping a gene boundary) (2) NCBI hot-links to nearest upstream and downstream genes for each location (3) statistical information about the query (4) whether the motif is a certain type of repeat (5) links for the reverse, complement and reverse-complement of the motif of interest and (6) hot-links to PubMed abstracts which mention the motif of interest. A software framework facilitates the continual development of new annotation modules. The tool is located at: http://genomics.wheatoncollege.edu/cgi-bin/lexicon.exe.

Animals↗

PubMed2003

Coded excitation with spectrum inversion (CEXSI) for ultrasound array imaging.

In this paper, a scheme called coded excitation with spectrum inversion (CEXSI) is presented. An established optimal binary code whose spectrum has no nulls and possesses the least variation is encoded as a burst for transmission. Using this optimal code, the decoding filter can be derived directly from its inverse spectrum. Various transmission techniques can be used to improve energy coupling within the system pass-band. We demonstrate its potential to achieve excellent decoding with very low (< 80 dB) side-lobes. For a 2.6 micros code, an array element with a center frequency of 10 MHz and fractional bandwidth of 38%, range side-lobes of about 40 dB have been achieved experimentally with little compromise in range resolution. The signal-to-noise ratio (SNR) improvement also has been characterized at about 14 dB. Along with simulations and experimental data, we present a formulation of the scheme, according to which CEXSI can be extended to improve SNR in sparse array imaging in general.

Algorithms↗