Maximum length sequence and Bessel diffusers using active technologies

Active technologies can enable room acoustic diffusers to operate over a wider bandwidth than passive devices, by extending the bass response. Active impedance control can be used to generate surface impedance distributions which cause wavefront dispersion, as opposed to the more normal absorptive or pressure-cancelling target functions. This paper details the development of two new types of active diffusers which are difficult, if not impossible, to make as passive wide-band structures. The first type is a maximum length sequence diffuser where the well depths are designed to be frequency dependent to avoid the critical frequencies present in the passive device, and so achieve performance over a finite-bandwidth. The second is a Bessel diffuser, which exploits concepts developed for transducer arrays to form a hybrid absorber–diffuser. Details of the designs are given, and measurements of scattering and impedance used to show that the active diffusers are operating correctly over a bandwidth of about 100 Hz to 1.1 kHz. Boundary element method simulation is used to show how more application-realistic arrays of these devices would behave

Active diffusers : some prototypes and 2D measurements

Diffusing devices are used to improve room acoustics in a wide variety of applications. The dispersion generated by current diffuser technologies is often limited to mid-to-high frequencies because low-frequency diffusers are usually too large to be easily accommodated. To extend the bandwidth of diffusers to a lower frequency a new approach is proposed, that is to use active control technology. In particular, active impedance techniques have been exploited to create non-absorbing diffusers, and hybrid structures that partly absorb while dispersing any reflected sound. This paper presents results mostly from a feedforward structure. It is found that achieving active dispersion without absorption other a worthwhile bandwidth can be more difficult than achieving active absorption due to the more complex target impedance that the controller needs to learn. Measurements on polar responses provide evidence that the active diffusers can achieve wider bandwidth dispersion. Boundary element modelling has enabled the design of these structures to be examined in more application-realistic set-ups

Prevalence of vertebral fractures on chest radiographs of elderly African American and Caucasian women.

The prevalence of vertebral fractures on routine chest radiographs of elderly Caucasian women was only 1.3 times higher than in African American (AA) women, a difference considerably smaller than reported in population studies. AAs with medical problems may have higher risk of vertebral fractures than previously suspected.IntroductionEarlier studies noted a 1.9- to 3.7-fold higher prevalence of vertebral fractures in Caucasian (CA) compared to African American (AA) women. These studies, however, may have suffered from selection bias. We reported that among women referred for bone density testing, the prevalence of vertebral fractures in AA was the same as in CA women. Suspecting that the latter might have been due to a referral bias, we examined the racial difference in the prevalence of vertebra fractures on chest radiographs of patients seeking general medical care, not selected for osteoporosis.MethodsConsecutive chest radiographs (N = 1,200) of women over age 60 were evaluated using Genant's semi-quantitative method. Patients' race and the presence of diseases or medications associated with increased fracture risk were ascertained from the electronic medical records.ResultsAmong 1,011 women (76% AA) with usable radiographs, 11% had moderate or severe vertebral fractures. The prevalence of vertebral fractures was 10.3% in 773 AA and 13% in 238 CA women (p = 0.248 for difference between races). The lack of difference persisted after controlling for age, smoking, use of glucocorticoids, or presence of cancer, rheumatoid arthritis, organ transplantation, and end-stage renal disease. Among all subjects, CA women were more likely to be diagnosed and treated for osteoporosis (p <0.001).ConclusionAmong subjects seeking medical care, the difference in the prevalence of vertebral fractures between AA and CA women is smaller than previously suspected. Greater attention to the detection of vertebral fractures and the management of osteoporosis is warranted in AA women with medical problems

How well do CMIP5 climate simulations replicate historical trends and patterns of meteorological droughts?

Assessing the uncertainties and understanding the deficiencies of climate models are fundamental to developing adaptation strategies. The objective of this study is to understand how well Coupled Model Intercomparison-Phase 5 (CMIP5) climate model simulations replicate ground-based observations of continental drought areas and their trends. The CMIP5 multimodel ensemble encompasses the Climatic Research Unit (CRU) ground-based observations of area under drought at all time steps. However, most model members overestimate the areas under extreme drought, particularly in the Southern Hemisphere (SH). Furthermore, the results show that the time series of observations and CMIP5 simulations of areas under drought exhibit more variability in the SH than in the Northern Hemisphere (NH). The trend analysis of areas under drought reveals that the observational data exhibit a significant positive trend at the significance level of 0.05 over all land areas. The observed trend is reproduced by about three-fourths of the CMIP5 models when considering total land areas in drought. While models are generally consistent with observations at a global (or hemispheric) scale, most models do not agree with observed regional drying and wetting trends. Over many regions, at most 40% of the CMIP5 models are in agreement with the trends of CRU observations. The drying/wetting trends calculated using the 3 months Standardized Precipitation Index (SPI) values show better agreement with the corresponding CRU values than with the observed annual mean precipitation rates. Pixel-scale evaluation of CMIP5 models indicates that no single model demonstrates an overall superior performance relative to the other models

The Fourth-Century AD Expansion of the Graeco-Roman Settlement of Karanis (Kom Aushim) in the Northern Fayum*

The Graeco-Roman town of Karanis, founded during the Ptolemaic Period in the north-eastern Fayum in the third century bc and long thought to have been abandoned in the third century ad actually saw a substantial expansion during the fourth century AD. With the creation of an 3 extension towards the west and the expansion of the eastern part, the town grew in both directions. We argue that this expansion may be related to a sudden rise of the water level in Lake Moeris (Lake Qarun), perhaps linked to a catastrophic dam breach in the eastern part of the Fayum, and the subsequent relocation of the inhabitants of the low-lying settlements north and east of the lake

Rituximab in combination with high-dose methylprednisolone for the treatment of chronic lymphocytic leukemia.

We observed that high-dose methylprednisolone (HDMP) and rituximab was well tolerated and had promising activity when used in combination to treat patients with fludarabine-refractory chronic lymphocytic leukemia (CLL). This prompted us to evaluate the use of these agents in frontline therapy. A total of 28 patients with a median age of 65 years enrolled in this study. Patients received HDMP at 1 g/m(2) each day for 3 days during each of the three 4-week cycles together with rituximab and prophylactic antimicrobial therapy. The treatment was well tolerated with few adverse events of grade III or higher. The overall response rate was 96% (N=27). Nine patients (32%) achieved a complete remission (CR), two of which were without detectable minimal residual disease (MRD). Six patients with MRD received consolidation with alemtuzumab; five of these patients achieved an MRD-negative CR. With over 3 years of follow-up median progression-free survival was 30.3 months with only 39% of patients requiring additional therapy, and an overall survival was 96%. This study demonstrates that HDMP and rituximab is an effective nonmyelosuppressive treatment combination for patients with CLL that warrants consideration particularly for patients with limited myeloid reserve that might not tolerate standard treatment regimens

Cirmtuzumab inhibits Wnt5a-induced Rac1 activation in chronic lymphocytic leukemia treated with ibrutinib.

Signaling via the B cell receptor (BCR) plays an important role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). This is underscored by the clinical effectiveness of ibrutinib, an inhibitor of Bruton's tyrosine kinase (BTK) that can block BCR-signaling. However, ibrutinib cannot induce complete responses (CR) or durable remissions without continued therapy, suggesting alternative pathways also contribute to CLL growth/survival that are independent of BCR-signaling. ROR1 is a receptor for Wnt5a, which can promote activation of Rac1 to enhance CLL-cell proliferation and survival. In this study, we found that CLL cells of patients treated with ibrutinib had activated Rac1. Moreover, Wnt5a could induce Rac1 activation and enhance proliferation of CLL cells treated with ibrutinib at concentrations that were effective in completely inhibiting BTK and BCR-signaling. Wnt5a-induced Rac1 activation could be blocked by cirmtuzumab (UC-961), an anti-ROR1 mAb. We found that treatment with cirmtuzumab and ibrutinib was significantly more effective than treatment with either agent alone in clearing leukemia cells in vivo. This study indicates that cirmtuzumab may enhance the activity of ibrutinib in the treatment of patients with CLL or other ROR1+ B-cell malignancies

Predicted and Observed Lateral Deformations of Anchored Retaining Walls

Backanalysis of deflection measurements for a diaphragm and a sheet pile wall in Holland has shown that the results are mostly sensitive to the profile of coefficients of subgrade reaction. A sensitivity study performed to compare the wall deflections calculated with the Menard and Terzaghi theory shows that the moduli according to Menard produces best agreement. The analyses were carried out using a one dimensional finite element programme. It is shown that displacement measurements obtained from easy to perform inclinometer surveys