Diffraction of a pulse by a three-dimensional corner

Three dimensional diffraction of sonic booms by corners of structure

Diffraction of a plane wave by a three-dimensional corner

By the superposition of the conical solution for the diffraction of a plane pulse by a three dimensional corner, the solution for a general incident plane wave is constructed. A numerical program is presented for the computation of the pressure distribution on the surface due to an incident plane wave of any wave form and at any incident angle. Numerical examples are presented to show the pressure signature at several points on the surface due to incident wave with a front shock wave, two shock waves in succession, or a compression wave with same peak pressure. The examples show that when the distance of a point on the surface from the edges or the vertex is comparable to the distance for the front pressure raise to reach the maximum, the peak pressure at that point can be much less than that given by a regular reflection, because the diffracted wave front arrives at that point prior to the arrival of the peak incident wave

Optimal Property Management Strategies

This paper examines the optimal operation strategies for income properties. Specifically, the rental rate and the operating expense should be set at levels to maximize the return on investment. The results suggest that for a given demand curve of a specific rental property, there exist optimal levels of the income ratio, the operating expense ratio, and the vacancy rate. With a Cobb-Douglas demand curve, we derived closed form solutions of these optimal ratios for a given income property. The relevant local comparative statics of these ratios also are derived. These comparative statics also provide insight into the optimal building size and optimal rehabilitation decisions. An empirical case study was conducted to demonstrate how the model can be applied in real life situations.Rental Property, Vacancy Rate; Operating Strategy, Profit Optimization

Maximum size binary matroids with no AG(3,2)-minor are graphic

We prove that the maximum size of a simple binary matroid of rank $r \geq 5$ with no AG(3,2)-minor is $\binom{r+1}{2}$ and characterise those matroids achieving this bound. When $r \geq 6$, the graphic matroid $M(K_{r+1})$ is the unique matroid meeting the bound, but there are a handful of smaller examples. In addition, we determine the size function for non-regular simple binary matroids with no AG(3,2)-minor and characterise the matroids of maximum size for each rank

A rat model of thyroid hormone-induced bone loss: Effect of antiresorptive agents on regional bone density and osteocalcin gene expression

Thyroid hormone has been shown to stimulate bone resorption. Both endogenous hyperthyroidism and exogenous thyroxine suppressive therapy have been associated with reduction in bone mineral density (BMD), but the patholophysiology of thyroxine-induced bone loss is not well understood. First we studied the effect of L-T4 (0.1-0.3 μg/g body weight ip/day) on bone turnover in rats by measuring regional BMDs and osteocalcin mRNA. Next we determined whether antiresorptive agents (calcitonin 1 μU/g ip/day or sodium etidronate given cyclically at 10 μg/g po for 3 consecutive days out of every week) could prevent bone loss. Groups of 10 male Sprague-Dawley rats each weighing 320-350 g were studied before and after 3 weeks of treatment. L-T4 treatment resulted in reduction in BMDs in the lumbar spine, tail, and femur as measured by dual energy X-ray absorptiometry, but there was no correlation with the dosage of L-T4 or the serum T4 level. Treatment with sodium etidronate or calcitonin alone did not alter the regional BMD. Cyclical sodium etidronate, but not calcitonin, was able to prevent the bone loss induced by L-T4 treatment. L-T4 caused a dose-dependent increase in femur osteocalcin mRNA concentration. Treatment with calcitonin resulted in 50% reduction of osteocalcin mRNA, but sodium etidronate had no effect. In conclusion, cyclical sodium etidronate prevents bone loss induced by exogenous L-T4 in rats and may be useful in preventing osteoporosis in patients given long term TSH-suppressive doses of thyroxine therapy.published_or_final_versio

Autistic traits, systemising, empathising, and theory of mind in transgender and non-binary adults

Abstract: Background: Prior research examining autistic traits in gender minority adults has reported mixed findings. Most prior studies did not include non-binary individuals. Little is known about the mechanisms shaping autistic traits in gender minority adults. This study examined autistic traits, as well as constructs related to the extreme male brain theory of autism and the mindblindness theory, in transgender and non-binary adults. Methods: An online survey was conducted to assess autism-related traits in 323 gender minority adults, including 74 transgender men (individuals assigned female at birth and identify as a man), 95 transgender women (individuals assigned male at birth and identify as a woman), 104 non-binary AFAB (individuals assigned female at birth and identify as non-binary), and 50 non-binary AMAB (individuals assigned male at birth and identify as non-binary). Autistic traits, systemising, empathising, and Theory of Mind (ToM) were measured using the Autism Spectrum Quotient (AQ), the short forms of the Systemising Quotient (SQ-Short) and the Empathy Quotient (EQ-Short), the 10-item version of the Empathy Quotient (EQ-10) and the Reading the Mind in the Eyes Test (Eyes Test). Participants’ scores on these measures were compared with previously published scores based on large-scale general population samples including thousands of participants. Results: On average, compared with control females in the general population samples, both transgender men and non-binary AFAB scored significantly higher on the AQ and the SQ-Short but scored significantly lower on the EQ-Short, the EQ-10, and the Eyes Test. No clear or consistent group differences emerged when transgender women and non-binary AMAB were compared with control males. Limitations: The present study does not have a large sample of gender minority adults. It has been argued that the measures employed may not provide a precise assessment of the psychological constructs of interest. The present study has a “non-clinical” sample. However, not all gender minorities have access to or require clinical services, and so a “non-clinical” sample may be more representative of the gender minority community as a whole than samples recruited through clinics. Conclusions: The current findings suggest a “masculinised” autism-related profile and reduced ToM in transgender men and in non-binary AFAB. These findings might be interpreted to support the extreme male brain theory of autism and the mindblindness theory. Further research is needed to corroborate these findings

Optimal Order and Efficiency for Iterations with Two Evaluations

The problem is to calculate a simple zero of a nonlinear function f. We consider rational iterations without memory which use two evaluations of f or its derivatives. It is shown that the optimal order is 2. This settles a conjecture of Kung and Traub that an iteration using n evaluations without memory is of order at most 2ⁿ⁻¹, for the case n=2. Furthermore we show that any rational two-evaluation iteration of optimal order must use either two evaluations of f or one evaluation of f and one of f'. From this result we completely settle the question of the optimal efficiency, in our efficiency measure, for any two-evaluation iteration without memory. Depending on the relative cost of evaluating f and f', the optimal efficiency is achieved by either Newton iteration or the iteration ᴪ

From industrialization to urbanization: the social consequences of changing fiscal incentives on local governments' behavior

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