797 research outputs found
The Segregation of Real Roots of Lower Orders
The purpose of this thesis is the presentation of the better algebraic methods of the segregation of real roots of equations of lower orders and a brief historical sketch of the advance made in the development of algebra. Mention is also made of a few of the men who have made notable contributions to this field of mathematics and the time, as nearly as it is possible to determine it, when new ideas were discovered
Acoustic and seismic signal processing for footsetp detection
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (leaves 83-84).The problem of detecting footsteps using acoustic and seismic sensors is approached from three different angles in this thesis. First, accelerometer data processing systems are designed to make footsteps more apparent to a human operator listening to accelerometer recordings. These systems work by modulating footstep signal energy into the ear's most sensitive frequency bands. Second, linear predictive modeling is shown to be an effective means to detect footsteps in accelerometer and microphone data. The time evolution of the third order linear prediction coefficients leads to the classical binary hypothesis testing framework. Lastly, a new method for blindly estimating the filters of a SIMO channel is presented. This method is attractive because it allows for a more tractable performance analysis.by Ross E. Bland.M.Eng
Pursuing a Shared Future in the Face of Globalization: Four Essential Questions
This paper discusses the “four-question” framework (Bland, Powell, & Ross, Barriers to dispute resolution: reflections on peacemaking and relationships between adversaries, 2012) that we and our colleagues developed in working to promote constructive dialogue and difficult compromises on the part of groups engaged in seeming intractable conflicts in Northern Ireland and Israeli/Palestine. The key feature of this framework is the need for the vision of a bearable shared future and commitment to pursue that future. Three other features of this framework are the need to build trust that commitments will be honored, the need for parties to understand and acknowledge the losses each will bear in accepting that future, and the need for the parties to settle for less than they feel justice demands, but also address the most serious current sources of injustice. This framework, we suggest, provides a useful lens for understanding and bridging the political divides apparent today in the US and many other democratic countries facing not only the economic threats and losses that globalization has imposed on vulnerable groups, but also threats and losses relating to weakening of community life and feelings of personal dignity We also discuss the phenomenon of loss aversion (Kahneman & Tversky, 2000) and its role in creating susceptibility to the rhetoric of hate-mongering populist leaders. We note the obvious need to provide a decent standard of living and greater security for the most vulnerable, but the further need to do so in a non-humiliating manner, and we also address the need to distinguish acceptable imperfect, difficult compromises from unacceptable ones
An upper limit to the dry merger rate at <z> ~ 0.55
We measure the fraction of Luminous Red Galaxies (LRGs) in dynamically close
pairs (with projected separation less than 20 kpc and velocity
difference less than 500 km s) to estimate the dry merger rate for
galaxies with and
in the 2dF-SDSS LRG and QSO (2SLAQ) redshift survey. For galaxies with a
luminosity ratio of or greater we determine a upper limit to
the merger fraction of 1.0% and a merger rate of
Mpc Gyr (assuming that all pairs merge on the shortest possible
timescale set by dynamical friction). This is significantly smaller than
predicted by theoretical models and suggests that major dry mergers do not
contribute to the formation of the red sequence at .Comment: 8 pages emulateapj style, 3 figures, accepted by AJ (March 2010
Effects of KDT501 on Metabolic Parameters in Insulin-Resistant Prediabetic Humans
Context: KDT501 is an isohumulone drug that has demonstrated beneficial effects on metabolic parameters in mice.
Objective: This study was intended to examine potential improvements in metabolism in humans.
Design and Setting: Changes in carbohydrate and lipid metabolism, along with inflammatory markers, were evaluated in prediabetic humans in a clinical research center.
Participants: Nine obese patients participated. All had prediabetes or normal glucose tolerance plus three features of metabolic syndrome.
Intervention: All participants were treated with escalating doses of KDT501 to a maximum dose of 1000 mg every 12 hours for a total of 28 days.
Outcome Measures: Changes in carbohydrate metabolism were measured with oral glucose tolerance, homeostatic model of insulin resistance, and euglycemic clamp; changes in plasma lipids and response to a lipid tolerance test; and changes in plasma inflammatory markers.
Results: The drug was well tolerated. After KDT501 treatment, plasma triglycerides were reduced at 4 hours during a lipid tolerance test. Furthermore, plasma adiponectin and high-molecular-weight adiponectin increased significantly, and plasma tumor necrosis factor-α decreased significantly. There were no significant changes in oral glucose tolerance test results or insulin sensitivity measures.
Conclusions: Despite the small sample size and the short duration of therapy, KDT501 administration reduced measures of systemic inflammation and improved postmeal plasma triglyceride levels, which may be beneficial in participants with insulin resistance or metabolic syndrome
Novel rat Alzheimer's disease models based on AAV-mediated gene transfer to selectively increase hippocampal Aβ levels
<p>Abstract</p> <p>Background</p> <p>Alzheimer's disease (AD) is characterized by a decline in cognitive function and accumulation of amyloid-β peptide (Aβ) in extracellular plaques. Mutations in amyloid precursor protein (APP) and presenilins alter APP metabolism resulting in accumulation of Aβ42, a peptide essential for the formation of amyloid deposits and proposed to initiate the cascade leading to AD. However, the role of Aβ40, the more prevalent Aβ peptide secreted by cells and a major component of cerebral Aβ deposits, is less clear. In this study, virally-mediated gene transfer was used to selectively increase hippocampal levels of human Aβ42 and Aβ40 in adult Wistar rats, allowing examination of the contribution of each to the cognitive deficits and pathology seen in AD.</p> <p>Results</p> <p>Adeno-associated viral (AAV) vectors encoding BRI-Aβ cDNAs were generated resulting in high-level hippocampal expression and secretion of the specific encoded Aβ peptide. As a comparison the effect of AAV-mediated overexpression of APPsw was also examined. Animals were tested for development of learning and memory deficits (open field, Morris water maze, passive avoidance, novel object recognition) three months after infusion of AAV. A range of impairments was found, with the most pronounced deficits observed in animals co-injected with both AAV-BRI-Aβ40 and AAV-BRI-Aβ42. Brain tissue was analyzed by ELISA and immunohistochemistry to quantify levels of detergent soluble and insoluble Aβ peptides. BRI-Aβ42 and the combination of BRI-Aβ40+42 overexpression resulted in elevated levels of detergent-insoluble Aβ. No significant increase in detergent-insoluble Aβ was seen in the rats expressing APPsw or BRI-Aβ40. No pathological features were noted in any rats, except the AAV-BRI-Aβ42 rats which showed focal, amorphous, Thioflavin-negative Aβ42 deposits.</p> <p>Conclusion</p> <p>The results show that AAV-mediated gene transfer is a valuable tool to model aspects of AD pathology <it>in vivo</it>, and demonstrate that whilst expression of Aβ42 alone is sufficient to initiate Aβ deposition, both Aβ40 and Aβ42 may contribute to cognitive deficits.</p
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District nursing staff and depression: a psychometric evaluation of Depression Attitude Questionnaire findings
Background: Mental health problems such as depression are common in primary care settings and patients with chronic medical problems are at an increased risk. This co-morbidity suggests that district nursing services are particularly likely to encounter psychological problems in their patients. Mental health problems are poorly recognised and inadequately treated in primary care. In part this may be due to stigmatising views of mental illness, which negatively influence help-seeking and user experiences. Likewise providers’ attitudes are likely to play a significant part in the management of such problems.
Objectives: The aims of this study were extend knowledge of district nursing staff attitudes to depression and explore the psychometric properties of a depression attitude measure used with this staff group.
Design and settings: The Depression Attitude Questionnaire (DAQ) was used within a postal questionnaire survey of district nursing services in three areas, Jersey (Channel Islands), Lewisham, and Hertfordshire.
Participants: All staff (community nurses, district nurses and home care staff) were contacted; 217 (66%) staff responded to the survey, and 189 (57%) completed the DAQ.
Results: Three factors were derived from the DAQ accounting for 47% of the variance. The factor solution appeared stable and provided meaningful dimensions, however the internal consistency of the measure and of its derived subscales was low (Cronbach's α between 0.59 and 0.64). The factors were labelled pessimism about depression and its treatment, tendency to defer to specialists, and professional ease in working with depressed patients. Staff responses revealed generally optimistic views concerning depression treatment, strongly rejecting deterministic attitudes to this condition.
Conclusions: The DAQ has been widely employed to measure and compare attitudes of staff from various disciplines and specialisms. The current evaluation has provided a more detailed examination of its psychometric properties than previously available, but low internal consistency levels indicate further examination of this area is warranted
Psychometric validation of the needs assessment tool : progressive disease in interstitial lung disease
ABSTRACT The inter-rater/test–retest reliability and construct validity of a palliative care needs assessment tool in interstitial lung disease (NAT:PD-ILD) were tested using NAT:PDILD- guided video-recorded consultations, and NAT:PD-ILD-guided consultations, and patient and carer-report outcomes (St George’s Respiratory Questionnaire (SGRQ)-ILD, Carer Strain Index (CSI)/Carer Support Needs Assessment Tool (CSNAT)). 11/16 items reached at least fair inter-rater agreement; 5 items reached at least moderate test–retest agreement. 4/6 patient constructs demonstrated agreement with SGRQ-I scores (Kendall’s tau-b, 0.24–20.36; P<0.05). 4/7 carer constructs agreed with the CSI/CSNAT items (kappa, 0.23–20.53). The NAT:PD-ILD is reliable and valid. Clinical effectiveness and implementation are to be evaluated
PRAXIS: low thermal emission high efficiency OH suppressed fibre spectrograph
PRAXIS is a second generation instrument that follows on from GNOSIS, which
was the first instrument using fibre Bragg gratings for OH background
suppression. The Bragg gratings reflect the NIR OH lines while being
transparent to light between the lines. This gives a much higher signal-noise
ratio at low resolution but also at higher resolutions by removing the
scattered wings of the OH lines. The specifications call for high throughput
and very low thermal and detector noise so that PRAXIS will remain sky noise
limited. The optical train is made of fore-optics, an IFU, a fibre bundle, the
Bragg grating unit, a second fibre bundle and a spectrograph. GNOSIS used the
pre-existing IRIS2 spectrograph while PRAXIS will use a new spectrograph
specifically designed for the fibre Bragg grating OH suppression and optimised
for 1470 nm to 1700 nm (it can also be used in the 1090 nm to 1260 nm band by
changing the grating and refocussing). This results in a significantly higher
transmission due to high efficiency coatings, a VPH grating at low incident
angle and low absorption glasses. The detector noise will also be lower.
Throughout the PRAXIS design special care was taken at every step along the
optical path to reduce thermal emission or stop it leaking into the system.
This made the spectrograph design challenging because practical constraints
required that the detector and the spectrograph enclosures be physically
separate by air at ambient temperature. At present, the instrument uses the
GNOSIS fibre Bragg grating OH suppression unit. We intend to soon use a new OH
suppression unit based on multicore fibre Bragg gratings which will allow
increased field of view per fibre. Theoretical calculations show that the gain
in interline sky background signal-noise ratio over GNOSIS may very well be as
high as 9 with the GNOSIS OH suppression unit and 17 with the multicore fibre
OH suppression unit.Comment: SPIE conference proceedings 915
The test–retest reliability of four functional mobility tests in apparently healthy adults
Background: Simple field tests are often used to assess functional mobility in clinical settings. Despite having many benefits, these tests are susceptible to measurement error and individual variation. Objectives: To examine the test-retest and absolute reliability of timed up and go test (TUG), five times sit-to-stand (FTSTS), stair climb test (SCT) and 6 minute walk (6MWT). Methods: Over two sessions, thirty-five subjects (30-74 years), repeated the five tests approximately four weeks apart. Test-retest reliability (intraclass correlations [ICC]) and absolute reliability (95% limit of agreements [95% LOA]; standard error of measurement [SEM] and minimum detectable change [MDC]) were calculated. Results: All five tests had high test-retest reliability (ICC > 0.95) although significant between session changes were present for the TUG and FTSTS (p < 0.05). FTSTS displayed the greatest measurement error whilst 95% LOA was the most conservative measure of absolute reliability. Conclusions: The results of this study indicate that the TUG, FTSTS, SCT and 6MWT are reliable when performed four weeks apart. Furthermore, the inclusion of SEM, MDC and 95% LOA provides reference values to aid in identifying changes over time above those of measurement error and individual variation
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