Psychoacoustic Analysis of Synthesized Jet Noise

An aircraft noise synthesis capability is being developed so the annoyance caused by proposed aircraft can be assessed during the design stage. To make synthesized signals as realistic as possible, high fidelity simulation is required for source (e.g., engine noise, airframe noise), propagation and receiver effects. This psychoacoustic study tests whether the jet noise component of synthesized aircraft engine noise can be made more realistic using a low frequency oscillator (LFO) technique to simulate fluctuations in level observed in recordings. Jet noise predictions are commonly made in the frequency domain based on models of time-averaged empirical data. The synthesis process involves conversion of the frequency domain prediction into an audible pressure time history. However, because the predictions are time-invariant, the synthesized sound lacks fluctuations observed in recordings. Such fluctuations are hypothesized to be perceptually important. To introduce time-varying characteristics into jet noise synthesis, a method has been developed that modulates measured or predicted 1/3-octave band levels with a (<20Hz) LFO. The LFO characteristics are determined through analysis of laboratory jet noise recordings. For the aft emission angle, results indicate that signals synthesized using a generic LFO are perceived as more similar to recordings than those using no LFO, and signals synthesized with an angle-specific LFO are more similar to recordings than those synthesized with a generic LFO

Analysis and Synthesis of Tonal Aircraft Noise Sources

Fixed and rotary wing aircraft operations can have a significant impact on communities in proximity to airports. Simulation of predicted aircraft flyover noise, paired with listening tests, is useful to noise reduction efforts since it allows direct annoyance evaluation of aircraft or operations currently in the design phase. This paper describes efforts to improve the realism of synthesized source noise by including short term fluctuations, specifically for inlet-radiated tones resulting from the fan stage of turbomachinery. It details analysis performed on an existing set of recorded turbofan data to isolate inlet-radiated tonal fan noise, then extract and model short term tonal fluctuations using the analytic signal. Methodologies for synthesizing time-variant tonal and broadband turbofan noise sources using measured fluctuations are also described. Finally, subjective listening test results are discussed which indicate that time-variant synthesized source noise is perceived to be very similar to recordings

Quantum Monte Carlo Study of Semiconductor Artificial Graphene Nanostructures

Semiconductor artificial graphene nanostructures where Hubbard model parameter $U/t$ can be of the order of 100, provide a highly controllable platform to study strongly correlated quantum many-particle phases. We use accurate variational and diffusion Monte Carlo methods to demonstrate a transition from antiferromagnetic to metallic phases for experimentally accessible lattice constant $a=50$ nm in terms of lattice site radius $\rho$, for finite sized artificial honeycomb structures nanopatterned on GaAs quantum wells containing up to 114 electrons. By analysing spin-spin correlation functions for hexagonal flakes with armchair edges and triangular flakes with zigzag edges, we show that edge type, geometry and charge nonuniformity affect the steepness and the crossover $\rho$ value of the phase transition. For triangular structures, the metal-insulator transition is accompanied with a smoother edge polarization transition.Comment: 5 pages, 5 figures; references added, several system sizes added, typos corrected; abstract update

Teledermatological monitoring of leg ulcers in cooperation with home care nurses

Objectives: To examine the feasibility and acceptance of teledermatology for wound management for patients with leg ulcers by home care nurses and evaluate the reduction of costs and the acceptance of teledermatology by patients and home care nurses

Primary intracerebral malignant fibrous histiocytoma mimicking a meningioma

We describe herein a patient with primary intracerebral malignant fibrous histiocytoma (MFH) to demonstrate this very rare central nervous system tumor. A 42-year-old male was admitted to our institute with the complaints of headache and speech impairment. Magnetic resonance imaging (MRI) revealed a tumor consistent with meningioma and we decided the surgery. The tumor was excised totally during the initial surgery. Histopathological examination revealed a mesenchymal tumor with an invasion of the adjacent brain and underlying dura mater. On the postoperative 4th month, the follow up MRI showed tumor recurrence at the same location and of similar size. Reoperation was performed and the tumor was again removed gross totally. However, the patient demonstrated a rapidly progressive course leading to death within the first year after the surgery. Two significant points of this case of primary central nervous system MFH are the rarity of its occurrence and its mimicking a meningioma

Parental and infant characteristics and childhood leukemia in Minnesota

<p>Abstract</p> <p>Background</p> <p>Leukemia is the most common childhood cancer. With the exception of Down syndrome, prenatal radiation exposure, and higher birth weight, particularly for acute lymphoid leukemia (ALL), few risk factors have been firmly established. Translocations present in neonatal blood spots and the young age peak of diagnosis suggest that early-life factors are involved in childhood leukemia etiology.</p> <p>Methods</p> <p>We investigated the association between birth characteristics and childhood leukemia through linkage of the Minnesota birth and cancer registries using a case-cohort study design. Cases included 560 children with ALL and 87 with acute myeloid leukemia (AML) diagnoses from 28 days to 14 years. The comparison group was comprised of 8,750 individuals selected through random sampling of the birth cohort from 1976–2004. Cox proportional hazards regression specific for case-cohort studies was used to compute hazard ratios (HR) and 95% confidence intervals (CIs).</p> <p>Results</p> <p>Male sex (HR = 1.41, 95% CI 1.16–1.70), white race (HR = 2.32, 95% CI 1.13–4.76), and maternal birth interval ≥ 3 years (HR = 1.31, 95% CI 1.01–1.70) increased ALL risk, while maternal age increased AML risk (HR = 1.21/5 year age increase, 95% CI 1.0–1.47). Higher birth weights (>3798 grams) (HRALL = 1.46, 1.08–1.98; HRAML = 1.97, 95% CI 1.07–3.65), and one minute Apgar scores ≤ 7 (HRALL = 1.30, 95% CI 1.05–1.61; HRAML = 1.62, 95% CI 1.01–2.60) increased risk for both types of leukemia. Sex was not a significant modifier of the association between ALL and other covariates, with the exception of maternal education.</p> <p>Conclusion</p> <p>We confirmed known risk factors for ALL: male sex, high birth weight, and white race. We have also provided data that supports an increased risk for AML following higher birth weights, and demonstrated an association with low Apgar scores.</p

Lateral humeral rotation osteotomy for the treatment of obstetrical palsy of the brachial plexus [Dogumsal braki·al pleksus felci·nde humerus lateral rotasyon osteotomi·si·]

Introduction: Obstetrical palsy of the brachial plexus secondary to a difficult labor remains to be a challenging clinical problem, causing persistent neurologic impairment with varying degrees of functional deficit of the upper extremity if not treated properly. In our country, a considerable number of children with plexopathy have been referred to an eligible hospital or surgeon in the late period after developing persistent shoulder contractures and deformities because of lack of appropriate management. The purpose of this retrospective study is to review the outcomes of humerus lateral rotational osteotomy in children who had persistent shoulder contractures and deformities because of birth palsy. Patients and Methods: Twenty cases, with internal rotation and adduction contractures of the shoulder with a resulting joint deformity or subluxation secondary to Erb's palsy, were managed with lateral rotational osteotomy of the humerus over a 10-year period (1990-2000). The average age of the patients was 8.1 years at the time of operation (range, 5-13 years). Follow-up averaged 8 years. The modified classification system of Mallet was used to assess the function of the upper extremity before the operation and at the latest follow-up. The outcomes were compared statistically. Results: According to the modified classification system of Mallet, the patients had a median score of 3 for global abduction, 2 for global external rotation, 2 for hand-to-neck ability and 2 for hand-to-mouth ability preoperatively. At the time of final follow-up, all patients had improved shoulder function and obtained a median modified Mallet score of 4 for all abilities. Only a patient could not succeed in hand-to-neck activity because of an elbow flexion contracture. As assessed with use of modified Mallet classification, there was significant improvement in upper extremity function after humerus lateral rotation osteotomy (P<0.05). Discussion: Fixed adduction and internal rotation contracture of the arm, with loss of external rotation of the shoulder, is the most frequent deformity of the extremity associated with Erb's type brachial plexus birth injury. If this contracture is not treated early enough, it may result in progressive glenohumeral joint deformity and incongruency. Humerus lateral rotation osteotomy is an effective salvage procedure, for patients with this type of contractures secondary to chronic obstetrical brachial plexus palsy, when tendon transfers cannot be performed because of incongruency of glenohumeral joint. The present study supports that humerus lateral rotation osteotomy not only increases the functional range of motion of the upper extremity, but also enables the activities of daily life much better

Midterm results of the Chiari pelvic ostetomy for acetabular dysplasia [Asetabuler displazide Chiari pelvik osteotomisinin orta dönem sonuçlari]

Objectives: We evaluated the midterm clinical and radiographic results of the Chiari pelvic osteotomy in the treatment of acetabular dysplasia. Patients and methods: Forty-two hips of 36 patients (23 females, 13 males; mean age 17 years; range 12 to 42 years) were treated with the Chiaxi pelvic osteotomy for painful acetabular dysplasia. Six patients (16.7%) had bilateral surgery. Preoperatively, the mean duration of hip pain and/or limping was 34.6 months and 12 hips exhibited mild-to-moderate osteoarthrosis. Clinically, the patients were evaluated with the Harris hip score and correlations were sought between the hip scores and radiographic measurements. The mean follow-up was 88 months (range 48 to 164 months). Results: After exclusion of one hip that required total hip arthroplasty 12 years after osteotomy, the mean Harris hip score increased from 73±5 preoperatively to 89±6 at the last follow-up. Postoperatively, 35 hips (85.4%) exhibited slight or no pain. Clinical results were excellent in 20 hips (48.8%), good in 15 hips (36.6%), and fair in six hips (14.6%). Thirty patients (83.3%) were satisfied with the operation. No significant correlations were found between Harris hip scores and the percentage coverage of the femoral head, center-edge angle, and acetabular angle. However, the percentage medialization of the distal fragment (r=0.28, p=0.042), the level of osteotomy (r= -0.6, p<0.0001), the severity of preoperative osteoarthrosis (r= -0.85, p<0.0001), and age (r= -0.66, p<0.0001) were significantly correlated with the hip scores. Complications included superficial infection in two hips, injury to the lateral femoral cutaneous nerve in 10 hips, and delayed union in two hips. Conclusion: Our results suggest that the Chiari pelvic osteotomy provides a significant clinical improvement in patients with painful acetabular dysplasia

Eccrine hidradenitis: case report and literature review

Neutrophilic eccrine hidradenitis is a self-limited dermatosis with spontaneous resolution. The clinical presentation and location of the lesions are variable. Histopathologically, neutrophilic eccrine hidradenitis is characterized by a predominantly neutrophilic or mononuclear infiltrate around the eccrine ducts with associated necrosis. Possible causes include malignant hematological disorders, tumors, side effects of chemotherapy and bacteria infections. We report a 16-month-old female patient with idiopathic neutropenia undergoing G-CSF therapy, who suddenly developed numerous papules on her trunk and extremities. The lesions resolved spontaneously within 6 weeks without treatment. The clinical and histopathological findings of the hitherto published 45 cases are reviewed