Capillary zone electrophoresis separation and collection of spermatozoa for the forensic analysis of sexual assault evidence

The processing of sexual assault kits (SAKs) relies on the genetic analysis of material extracted from swabs collected from the assault victim. A vital step in producing an identifiable DNA profile of the perpetrator is the effective separation of perpetrator (sperm) and victim (epithelial) DNA that have been isolated from the collected evidence. We report the use of capillary zone electrophoresis for the separation of intact sperm from whole and lysed epithelial cells in SAKs. The separated components are deposited into wells of a microtiter plate using a computer-controlled fraction collector, and quantitative PCR is used to verify the collection of sperm cells by targeted amplification of male DNA. We present results from simulated sexual assault samples that have been aged for up to 18 months, as well as vaginal swabs from authentic forensic kits. Components extracted from the vaginal swabs from the SAK comigrated with an aged semen sample at 6.25 ± 0.25 min. Epithelial cells migrated from 10-12 min, producing baseline resolution of the components. Sperm cells were collected in a microtiter plate for downstream analysis.     

Valid strain measurements for structural dynamic testing

Experimental Techniques -     

Cyclic variability of pulsed spray vapor fields

 A two wavelength extinction technique is used to quantitatively measure the temporal fuel vapor field produced by pulsed automotive fuel injectors. Line-of-sight measurements are spatially deconvoluted to yield a picture of the overall, cycle-averaged, radial vapor concentration profiles. Vapor measurements are also given for single, consecutive, injection pulses, showing cycle-to-cycle variations in the vapor field. Methods to characterize the cyclic variability in the vapor field of a pulsed spray are discussed. As an illustrative example, the differences between an air assist and a non-air assist injector are shown as a function of duty cycle and axial location. Received: 11 August 1997/Accepted: 10 February 1998     

ENERGY AUDIT PROGRAMS VERSUS MARKET INCENTIVES AS INDUCEMENTS TO UNDERTAKE ENERGY CONSERVATION RETROFITS

Sometimes policymakers seek to influence economic activity merely by providing information, rather than by manipulating relative prices through taxation or subsidization. Household energy audits are an example. Furthermore, these programs are sometimes intended to increase the probability of a particular discrete outcome, such as whether or not the household is motivated to install energy-conservation retrofits. We use a utility-theoretic model for households' discrete decisions to install attic insulation with and without participation in an energy audit program. We find that (i) self-selection bias in naive models seems to give the audit program roughly twice the credit it deserves, and (ii) policy measures designed to influence retrofit costs or energy prices may have more discernible direct effects on attic insulation retrofit activity than do audit programs.     

The oxidation of cinnamaldehyde with alkaline hydrogen peroxide

The oxidation of cinnamaldehyde (3-phenyl-2-propenal) by alkaline peroxide results in epoxidation of the double bond to form cinnamaldehyde epoxide (3-phenyl-2,3-epoxy-propanal) which undergoes further reaction by ring opening and side chain cleavage to yield benzaldehyde and acidic fragments. The reactions are first-order in the organic substrates and perhydroxyl anion and second-order overall. In the presence of alkali alone, two further reactions take place in which cinnamaldehyde and cinnamaldehyde epoxide side chains are cleaved by reaction with hydroxide ion to form benzaldehyde and side chain fragments. These reactions are first-order in the organic substrates and hydroxide ion and second-order overall. Increasing solvent polarity accelerates the rates of reaction and reaction mechanisms have been proposed to describe the observed kinetic behavior. The stereoselectivity of the epoxidation reaction has been examined in terms of an existing model for epoxidation of α, β-unsaturated ketones by alkaline peroxide. © 1993 John Wiley & Sons, Inc.     

A spatial rainfall simulator for crop production modeling in Southern Africa

This paper describes a methodology for simulating rainfall in dekads across a set of spatial units in areas where long-term meteorological records are available for a small number of sites only. The work forms part of a larger simulation model of the food system in a district of Zimbabwe, which includes a crop production component for yields of maize, small grains and groundnuts. Only a limited number of meteorological stations are available within or surrounding the district that have long time series of rainfall records. Preliminary analysis of rainfall data for these stations suggested that intra-seasonal temporal correlation was negligible, but that rainfall at any given station was correlated with rainfall at neighbouring stations. This spatial correlation structure can be modeled using a multivariate normal distribution consisting of 30 related variables, representing dekadly rainfall in each of the 30 wards. For each ward, log-transformed rainfall for each of the 36 dekads in the year was characterized by a mean and standard deviation, which were interpolated from surrounding meteorological stations. A covariance matrix derived from a distance measure was then used to represent the spatial correlation between wards. Sets of random numbers were then drawn from this distribution to simulate rainfall across the wards in any given dekad. Cross-validation of estimated rainfall parameters against observed parameters for the one meteorological station within the district suggests that the interpolation process works well. The methodology developed is useful in situations where long-term climatic records are scarce and where rainfall shows pronounced spatial correlation, but negligible temporal correlation.     

Nonlinear Model Predictive Control via Feasibility-Perturbed Sequential Quadratic Programming

Model predictive control requires the solution of a sequence of continuous optimization problems that are nonlinear if a nonlinear model is used for the plant. We describe briefly a trust-region feasibility-perturbed sequential quadratic programming algorithm (developed in a companion report), then discuss its adaptation to the problems arising in nonlinear model predictive control. Computational experience with several representative sample problems is described, demonstrating the effectiveness of the proposed approach.     

Spline fitting discontinuous functions given just a few Fourier coefficients

This paper considers the use of polynomial splines to approximate periodic functions with jump discontinuities of themselves and their derivatives when the information consists only of the first few Fourier coefficients and the location of the discontinuities. Spaces of splines are introduced which include, members with discontinuities at those locations. The main results deal with the orthogonal projection of such a spline space on spaces of trigonometric polynomials corresponding to the known coefficients. An approximation is defined based on inverting this projection. It is shown that when discontinuities are sufficiently far apart, the projection is invertible, its inverse has norm close to 1, and the approximation is nearly as good as directL ₂ approximation by members of the spline space. An example is given which illustrates the results and which is extended to indicate how the approximation technique may be used to provide smoothing which which accurately represents discontinuities.