The use of special exceptions in zoning practice

Thesis (M.C.P.) Massachusetts Institute of Technology. Dept. of Architecture, 1951.Bibliography: leaf 54.by Owen W. Burnham and Morris E. Johnson.M.C.P

Optimised design of nested oblong tube energy absorbers under lateral impact loading

Dynamic lateral crushing of mild steel (DIN 2393) nested tube systems was conducted using a ZWICK ROELL impact tester. The tests were performed with impact velocities ranging between 3 and 5 m/s, achieved using a fixed mass impinging onto the specimens under the influence of gravity. The various nested tube systems consisted of one standard and one optimised design. Their crushing behaviour and energy absorption capabilities were obtained and analysed. In addition to the experimental work, numerical simulations using the explicit code LS-DYNA were conducted; boundary conditions matching those observed in experiments were applied to the models. Results from the numerical method were compared against those obtained from experiments. An over-prediction in force-deflection responses was obtained from the numerical code. An attempt was made to explain this inconsistency on the basis of the formation of plastic hinges and the validity of strain rate parameters used in the Cowper Symonds relation. It was found that the optimised energy absorbers exhibited a more desirable force-deflection response than their standard counterparts due to a simple design modification which was incorporated in the optimised design

Verbal and visuospatial deficits in dementia with Lewy bodies

This is the publisher's version, also available electronically from http://www.neurology.org/content/65/8/1232.Objective: To investigate the cognitive decline in dementia with Lewy bodies (DLBs) and characterize the contribution of Lewy bodies (LBs) to cognitive impairment in the presence of concurrent Alzheimer disease (AD). Methods: Cognitive deficits and rates of progression attributable to DLB and AD neuropathology were investigated in three groups of participants from the longitudinal cohort of the Alzheimer Disease Research Center at Washington University with autopsy-confirmed diagnoses of pure DLB (n = 9), mixed DLB/AD (n = 57), and pure AD (n = 66). Factor analysis was used to recover latent constructs in a comprehensive psychometric test battery, analysis of variance was used to test group differences on the observed dimensions, and random effects models were used to test longitudinal rates of cognitive decline. Results: Patients with AD pathology performed worse on the verbal memory dimension. Patients with LB pathology performed worse on the visuospatial dimension. Combined pathology affected visuospatial performance but not verbal memory. The rate of cognitive decline in the DLB, DLB/AD combined, and the pure AD groups was equivalent. Conclusions: The comorbid presence of DLB and AD alters the cognitive presentation of visuospatial deficits in dementia but does not alter dementia progression. Both visuospatial and verbal abilities declined at similar rates across the three patient groups. DLB diagnosis may be improved, particularly when there is comorbid AD, by using domain-specific testing

String Theory and Water Waves

We uncover a remarkable role that an infinite hierarchy of non-linear differential equations plays in organizing and connecting certain {hat c}<1 string theories non-perturbatively. We are able to embed the type 0A and 0B (A,A) minimal string theories into this single framework. The string theories arise as special limits of a rich system of equations underpinned by an integrable system known as the dispersive water wave hierarchy. We observe that there are several other string-like limits of the system, and conjecture that some of them are type IIA and IIB (A,D) minimal string backgrounds. We explain how these and several string-like special points arise and are connected. In some cases, the framework endows the theories with a non-perturbative definition for the first time. Notably, we discover that the Painleve IV equation plays a key role in organizing the string theory physics, joining its siblings, Painleve I and II, whose roles have previously been identified in this minimal string context.Comment: 49 pages, 4 figure

Personality traits distinguishing dementia with Lewy bodies from Alzheimer disease

This is the publisher's version, also available electronically from http://www.neurology.org/content/68/22/1895.Objective: To identify personality traits that distinguish dementia with Lewy bodies (DLB) from Alzheimer disease (AD). Methods: We examined 290 participants enrolled in a longitudinal study (nondemented control = 34, DLB = 128, AD = 128) followed to autopsy. As part of the annual interview with the collateral source, the clinician asked about specific changes in personality, interests, and drives based on items from the Blessed Dementia Scale (BDS). Statistical analysis was performed using χ2 and Fisher exact tests. Factor analysis was performed to determine underlying structure and receiver operating characteristic curves assessed the ability for each of three derived factors to discriminate DLB from AD. Results: The sample was evaluated for a mean of 4.8 visits (range 1 to 14) with a mean age of 77.6 ± 9.9 years. The participants' cognitive status ranged from nondemented (Clinical Dementia Rating [CDR] 0) through all stages of dementia (CDR ≥ 0.5). Personality traits that distinguished DLB included diminished emotional responsiveness (p = 0.004), relinquishing hobbies (p = 0.01), growing apathy (p = 0.03), and purposeless hyperactivity (p = 0.003). Factor analyses of the BDS revealed a PASSIVE factor (diminished emotional responsiveness, relinquished hobbies, growing apathy, and purposeless hyperactivity) explaining 10.4% of variance and that DLB was more likely to manifest these personality traits than AD (p = 0.001). The PASSIVE factor discriminated DLB from AD (area under the curve = 0.61, 95% CI: 0.54 to 0.68, p = 0.006). Any change in personality is associated with the presence of visual hallucinations. Conclusions: Our results suggest that incorporating a brief, simple inventory of personality traits may improve the identification of individuals with dementia with Lewy bodies

Longitudinal Study of the Transition From Healthy Aging to Alzheimer Disease

BACKGROUND: Detection of the earliest cognitive changes signifying Alzheimer disease is difficult. OBJECTIVE: To model the cognitive decline in preclinical Alzheimer disease. DESIGN: Longitudinal archival study comparing individuals who became demented during follow-up and people who remained nondemented on each of 4 cognitive factors: global, verbal memory, visuospatial, and working memory. SETTING: Alzheimer Disease Research Center, Washington University School of Medicine, St Louis, Missouri. PARTICIPANTS: One hundred thirty-four individuals who became demented during follow-up and 310 who remained nondemented. MAIN OUTCOME MEASURES: Inflection point in longitudinal cognitive performance. RESULTS: The best-fitting model for each of the 4 factors in the stable group was linear, with a very slight downward trend on all but the Visuospatial factor. In contrast, a piecewise model with accelerated slope after a sharp inflection point provided the best fit for the group that progressed. The optimal inflection point for all 4 factors was prior to diagnosis of dementia: Global, 2 years; Verbal and Working Memory, 1 year; and Visuospatial, 3 years. These results were also obtained when data were limited to the subset (n = 44) with autopsy-confirmed Alzheimer disease. CONCLUSIONS: There is a sharp inflection point followed by accelerating decline in multiple domains of cognition, not just memory, in the preclinical period in Alzheimer disease when there is insufficient cognitive decline to warrant clinical diagnosis using conventional criteria. Early change was seen in tests of visuospatial ability, most of which were speeded. Research into early detection of cognitive disorders using only episodic memory tasks may not be sensitive to all of the early manifestations of disease

Tachyon Condensation, Open-Closed Duality, Resolvents, and Minimal Bosonic and Type 0 Strings

Type 0A string theory in the (2,4k) superconformal minimal model backgrounds and the bosonic string in the (2,2k-1) conformal minimal models, while perturbatively identical in some regimes, may be distinguished non-perturbatively using double scaled matrix models. The resolvent of an associated Schrodinger operator plays three very important interconnected roles, which we explore perturbatively and non-perturbatively. On one hand, it acts as a source for placing D-branes and fluxes into the background, while on the other, it acts as a probe of the background, its first integral yielding the effective force on a scaled eigenvalue. We study this probe at disc, torus and annulus order in perturbation theory, in order to characterize the effects of D-branes and fluxes on the matrix eigenvalues. On a third hand, the integrated resolvent forms a representation of a twisted boson in an associated conformal field theory. The entire content of the closed string theory can be expressed in terms of Virasoro constraints on the partition function, which is realized as wavefunction in a coherent state of the boson. Remarkably, the D-brane or flux background is simply prepared by acting with a vertex operator of the twisted boson. This generates a number of sharp examples of open-closed duality, both old and new. We discuss whether the twisted boson conformal field theory can usefully be thought of as another holographic dual of the non-critical string theory.Comment: 37 pages, some figures, LaTe

Optimized design of a low-resistance electrical conductor for the multimegahertz range

We propose a design for a conductive wire composed of several mutually insulated coaxial conducting shells. With the help of numerical optimization, it is possible to obtain electrical resistances significantly lower than those of a heavy-gauge copper wire or litz wire in the 2–20 MHz range. Moreover, much of the reduction in resistance can be achieved for just a few shells; in contrast, litz wire would need to contain ∼ 10[superscript 4] strands to perform comparably in this frequency range

Radial artery access site complications during cardiac procedures, clinical implications and potential solutions : the role of nitric oxide

Supported by the European Social Fund and Scottish Funding Council as part of Developing Scotland’s Workforce in the Scotland 2014-2020 European Structural and Investment Fund Programme.Percutaneous coronary intervention for the treatment of coronary artery disease is most commonly performed in the UK through the radial artery, as this is safer than the femoral approach. However, despite improvements in technology and techniques, complications can occur. The most common complication, arterial spasm, can cause intense pain and, in some cases, procedural failure. The incidence of spasm is dependent on several variables, including operator experience, artery size, and equipment used. An anti-spasmolytic cocktail can be applied to reduce spasm, which usually includes an exogenous nitric oxide (NO) donor (glyceryl trinitrate). NO is an endogenous local vasodilator and therefore is a potential target for anti-spasm intervention. However, systemic administration can result in unwanted side-effects, such as hypotension. A method that adopts local delivery of NO might be advantageous. This review article describes the mechanisms involved in radial artery spasm, discusses the advantages and disadvantages of current strategies to reduce spasm, and highlight the potential of NO-loaded nanoporous materials for use in this setting.Publisher PDFPeer reviewe