Studies of police radar

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.Accompanying cassette titled: Radar field test.Bibliography: leaf 18.by Allen Yee.B.S

Multiwavelength Mass Comparisons of the z~0.3 CNOC Cluster Sample

Results are presented from a detailed analysis of optical and X-ray observations of moderate-redshift galaxy clusters from the Canadian Network for Observational Cosmology (CNOC) subsample of the EMSS. The combination of extensive optical and deep X-ray observations of these clusters make them ideal candidates for multiwavelength mass comparison studies. X-ray surface brightness profiles of 14 clusters with 0.17<z<0.55 are constructed from Chandra observations and fit to single and double beta-models. Spatially resolved temperature analysis is performed, indicating that five of the clusters in this sample exhibit temperature gradients within their inner 60-200 kpc. Integrated spectra extracted within R_2500 provide temperature, abundance, and luminosity information. Under assumptions of hydrostatic equilibrium and spherical symmetry, we derive gas and total masses within R_2500 and R_200. We find an average gas mass fraction within R_200 of 0.136 +/- 0.004, resulting in Omega_m=0.28 +/- 0.01 (formal error). We also derive dynamical masses for these clusters to R_200. We find no systematic bias between X-ray and dynamical methods across the sample, with an average M(dyn)/M(X-ray) = 0.97 +/- 0.05. We also compare X-ray masses to weak lensing mass estimates of a subset of our sample, resulting in a weighted average of M(lens)/M(X-ray) of 0.99 +/- 0.07. We investigate X-ray scaling relationships and find powerlaw slopes which are slightly steeper than the predictions of self-similar models, with an E(z)^(-1) Lx-Tx slope of 2.4 +/- 0.2 and an E(z) M_2500-Tx slope of 1.7 +/- 0.1. Relationships between red-sequence optical richness (B_gc,red) and global cluster X-ray properties (Tx, Lx and M_2500) are also examined and fitted.Comment: Astrophysical Journal, 48 pages, 11 figures, LaTeX. Added correction to surface brightness normalization of MS1512.4+3647, corrections to sample gas mass fractions and calculated value of Omega_m. Figure resolution has been reduced to comply with astro-ph upload requirement

Eliminating the Racial Disparity in Classroom Exclusionary Discipline

Advocates call for schools with high suspension rates to receive technical assistance in adopting “proven-effective” systematic supports. Such supports include teacher professional development. This call is justified given evidence that good teaching matters. But what types of professional development should be funded? Increasingly, research points to the promise of programs that are sustained, rigorous, and focused on teachers’ interactions with students. The current study tests whether a professional development program with these three characteristics helped change teachers’ use of exclusionary discipline practices—especially with their African American students. Exclusionary discipline is when a classroom teacher sends a student to the administrators’ office for perceived misbehavior. Administrators then typically assign a consequence, usually in the form of suspension (in-school or out-of school). The My Teaching Partner-Secondary (MTP-S) aims to improve teachers’ interactions with their students when implementing instruction and managing behavior. MTP-S helps teachers offer clear routines, implement consistent rules, and monitor behavior in a proactive way. The program also supports teachers in developing warm, respectful relationships that recognize students’ needs for autonomy and leadership. Teachers are paired with a coach for an entire school year (sustained approach), they regularly reflect on videorecordings of their classroom instruction and carefully observe how they interact with students, and they apply the validated Classroom Assessment Scoring System (CLASS-S) to improve the quality of their interactions (rigorous approach). In the current study, a randomized controlled trial found that teachers receiving MTP-S relied less on exclusionary discipline compared to the control teachers. Specifically, MTP-S teachers issued fewer exclusionary discipline referrals to their African American students. This is the first study to show that programs like MTP-S that focus on teacher-student interactions in a sustained manner using a rigorous approach can actually reduce the disproportionate use of exclusionary discipline with African American students. More broadly, the findings offer policymakers direction in identifying types of professional development programs that have promise for reducing the racial discipline gap

Gene expression profiling to study racial differences after heart transplantation.

BackgroundThe basis for increased mortality after heart transplantation in African Americans and other non-Caucasian racial groups is poorly defined. We hypothesized that increased risk of adverse events is driven by biologic factors. To test this hypothesis in the Invasive Monitoring Attenuation through Gene Expression (IMAGE) study, we determined whether the event rate of the primary outcome of acute rejection, graft dysfunction, death, or retransplantation varied by race as a function of calcineurin inhibitor (CNI) levels and gene expression profile (GEP) scores.MethodsWe determined the event rate of the primary outcome, comparing racial groups, stratified by time after transplant. Logistic regression was used to compute the relative risk across racial groups, and linear modeling was used to measure the dependence of CNI levels and GEP score on race.ResultsIn 580 patients monitored for a median of 19 months, the incidence of the primary end point was 18.3% in African Americans, 22.2% in other non-Caucasians, and 8.5% in Caucasians (p &lt; 0.001). There were small but significant correlations of race and tacrolimus trough levels to the GEP score. Tacrolimus levels were similar among the races. Of patients receiving tacrolimus, other non-Caucasians had higher GEP scores than the other racial groups. African American recipients demonstrated a unique decrease in expression of the FLT3 gene in response to higher tacrolimus levels.ConclusionsAfrican Americans and other non-Caucasian heart transplant recipients were 2.5-times to 3-times more likely than Caucasians to experience outcome events in the Invasive Monitoring Attenuation through Gene Expression study. The increased risk of adverse outcomes may be partly due to the biology of the alloimmune response, which is less effectively inhibited at similar tacrolimus levels in minority racial groups

Finite-source and finite-lens effects in astrometric microlensing

The aim of this paper is to study the astrometric trajectory of microlensing events with an extended lens and/or source. We consider not only a dark lens but also a luminous lens as well. We find that the discontinuous finite-lens trajectories given by Takahashi (2003) will become continuous in the finite-source regime. The point lens (source) approximation alone gives an under (over)estimation of the astrometric signal when the size of the lens and source are not negligible. While the finiteness of the source is revealed when the lens transits the surface of the source, the finite-lens signal is most prominent when the lens is very close to the source. Astrometric microlensing towards the Galactic bulge, Small Magellanic Cloud and M31 are discussed, which indicate that the finite-lens effect is beyond the detection limit of current instruments. Nevertheless, it is possible to distinguish between self-lensing and halo lensing through a (non-)detection of the astrometric ellipse. We also consider the case where the lens is luminous itself, as has been observed where a lensing event was followed up with the Hubble Space Telescope. We show that the astrometric signal will be reduced in a luminous-lens scenario. The physical properties of the event, such as the lens-source flux ratio, the size of the lens and source nevertheless can be derived by fitting the astrometric trajectory.Comment: 12 pages, 12 figures, 1 table, published in MNRA

X-ray and weak lensing measurements of the mass profile of MS1008.1-1224: Chandra and VLT data

We analyse the Chandra dataset of the galaxy cluster MS1008.1-1224 to recover an estimate of the gravitating mass as function of the radius and compare these results with the weak lensing reconstruction of the mass distribution obtained from deep FORS1-VLT multicolor imaging. Even though the X-ray morphology is disturbed with a significant excess in the northern direction suggesting that the cluster is not in a relaxed state, we are able to match the two mass profiles both in absolute value and in shape within 1 sigma uncertainty and up to 1100 h50^-1 kpc. The recovered X-ray mass estimate does not change by using either the azimuthally averaged gas density and temperature profiles or the results obtained in the northern sector alone where the signal-to-noise ratio is higher.Comment: 5 pages. Accepted for publication in A&A Letter

Undescended testis: 513 patients’ characteristics, age at orchidopexy and patterns of referral

10.1136/archdischild-2013-305225Archives of Disease in Childhood995401-40

Space–charge limited current in nanodiodes: Ballistic, collisional, and dynamical effects

This Perspective reviews the fundamental physics of space–charge interactions that are important in various media: vacuum gap, air gap, liquids, and solids including quantum materials. It outlines the critical and recent developments since a previous review paper on diode physics [Zhang et al. Appl. Phys. Rev. 4, 011304 (2017)] with particular emphasis on various theoretical aspects of the space–charge limited current (SCLC) model: physics at the nano-scale, time-dependent, and transient behaviors; higher-dimensional models; and transitions between electron emission mechanisms and material properties. While many studies focus on steady-state SCLC, the increasing importance of fast-rise time electric pulses, high frequency microwave and terahertz sources, and ultrafast lasers has motivated theoretical investigations in time-dependent SCLC. We particularly focus on recent studies in discrete particle effects, temporal phenomena, time-dependent photoemission to SCLC, and AC beam loading. Due to the reduction in the physical size and complicated geometries, we report recent studies in multi-dimensional SCLC, including finite particle effects, protrusive SCLC, novel techniques for exotic geometries, and fractional models. Due to the importance of using SCLC models in determining the mobility of organic materials, this paper shows the transition of the SCLC model between classical bulk solids and recent two-dimensional (2D) Dirac materials. Next, we describe some selected applications of SCLC in nanodiodes, including nanoscale vacuum-channel transistors, microplasma transistors, thermionic energy converters, and multipactor. Finally, we conclude by highlighting future directions in theoretical modeling and applications of SCLC.Peer-reviewed (ritrýnd grein

Radio Jets in Galaxies with Actively Accreting Black Holes: new insights from the SDSS

The majority of nearby radio-loud AGN are found in massive, old elliptical galaxies with weak emission lines. At high redshifts,however, most known radio AGN have strong emission lines. In this paper, we examine a subset of radio AGN with emission lines selected from the Sloan Digital Sky Survey. The probability for a nearby radio AGN to have emission lines is a strongly decreasing function of galaxy mass and an increasing function of radio luminosity above 10^25 W/Hz. Emission line and radio luminosities are correlated, but with large dispersion. At a given radio power, AGN with small black holes have higher [OIII] luminosities (which we interpret as higher accretion rates) than AGN with big black holes. However, if we scale both radio and emission line luminosities by the black hole mass, we find a correlation between normalized radio power and accretion rate in Eddington units that is independent of black hole mass. There is also a clear correlation between normalized radio power and the age of the stellar population in the galaxy. Present-day AGN with the highest normalized radio powers are confined to galaxies with small black holes. High-redshift, high radio-luminosity AGN could be explained if big black holes were similarly active at earlier cosmic epochs. To investigate why only a small fraction of emission line AGN become radio loud, we create matched samples of radio-loud and radio-quiet AGN and compare their host galaxy properties and environments. The main difference lies in their environments; our local density estimates are a factor 2 larger around the radio-loud AGN. We propose a scenario in which radio-loud AGN with emission lines are located in galaxies where accretion of both cold and hot gas can occur simultaneously. (Abridged)Comment: 18 figures, submitted to MNRA

Advanced Glycation End Product Interventions Reduce Diabetes-Accelerated Atherosclerosis

Advanced glycation end product (AGE) formation may contribute to the progression of atherosclerosis, particularly in diabetes. The present study explored atherosclerosis in streptozotocin-induced diabetic apolipoprotein E–deficient (apoE�/�) mice that were randomized (n � 20) to receive for 20 weeks no treatment, the AGE cross-link breaker ALT-711, or the inhibitor of AGE formation aminoguanidine (AG). A sixfold increase in plaque area with diabetes was attenuated by 30 % with ALT-711 and by 40 % in AG-treated mice. Regional distribution of plaque demonstrated no reduction in plaque area or complexity within the aortic arch with treatment, in contrast to the thoracic and abdominal aortas, where significant attenuation was seen. Diabetes-associated accumulation of AGEs in aorta