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frequency compression

Jianjia Yi, Sawyer D Campbell, Rui Feng, Shah Nawaz Burokur, Douglas H Werner
Complex electromagnetic structures can be designed by exploiting the concept of spatial coordinate transformations. In this paper, we define a coordinate transformation scheme that enables one to taper the electric field between two waveguides of different cross-sections. The electromagnetic field launched from the wide input waveguide is compressed in the proposed field tapering device and guided into the narrow output waveguide. In closed rectangular waveguide configurations, the taper can further play the role of a mode selector due to the output waveguide's cut-off frequency...
January 8, 2018: Optics Express
Xu Ma, Fang Yang, Sicong Liu, Jian Song
With the rapid development of light emitting diode (LED), visible light communication (VLC) becomes an important technique for information transmission including underwater applications. However, accurate channel estimation for underwater VLC is still challenging due to the complex environment of the underwater VLC channel. In this paper, by utilizing a proper approximation, where the channel attenuation is linear with the frequency, a new compressive sensing (CS) based channel estimation approach is proposed...
January 8, 2018: Optics Express
Zhijing Zhu, Hao Chi, Tao Jin, Shilie Zheng, Xianbin Yu, Xiaofeng Jin, Xianmin Zhang
In this Letter, we propose an approach to achieving photonics-enabled compressive sensing of sparse wideband radio frequency signals in which an incoherent broadband source is applied, and the mixing and integration functions are realized in the optical domain. A spectrum shaper is employed to slice and encode the spectrum of the broadband light according to a predetermined random sequence. Because of the dispersion-induced group delay, the mixing between the incoming signal and the random bit sequence is achieved...
January 15, 2018: Optics Letters
Pavel A Cheremkhin, Ekaterina A Kurbatova
Compression of digital holograms can significantly help with the storage of objects and data in 2D and 3D form, its transmission, and its reconstruction. Compression of standard images by methods based on wavelets allows high compression ratios (up to 20-50 times) with minimum losses of quality. In the case of digital holograms, application of wavelets directly does not allow high values of compression to be obtained. However, additional preprocessing and postprocessing can afford significant compression of holograms and the acceptable quality of reconstructed images...
January 1, 2018: Applied Optics
Jelena Bosnjak, Silva Soldo Butkovic, Snjezana Miskov, Lejla Coric, Ana Jadrijevic-Tomas, Vlatka Mejaski-Bosnjak
OBJECTIVE: The aim of the study is to describe types of epileptic seizures in patients with pineal gland cyst (PGC) and their outcome during follow up period (6-10 years). We wanted to determine whether patients with epilepsy differ in PGC volume and compression of the PGC on surrounding brain structures compared to patients with PGC, without epilepsy. PATIENTS AND METHODS: We analyzed prospectivelly 92 patients with PGC detected on magnetic resonance (MR) of the brain due to various neurological symptoms during the period 2006-2010...
January 4, 2018: Clinical Neurology and Neurosurgery
Kimberly Hamilton, Brandon Rocque, Nathaniel Brooks
BACKGROUND: Deer hunting is popular in much of the United States. In Wisconsin, use of tree stands for hunting is common. Spine surgeons at a Level 1 Trauma Center observed a high incidence of spine and spinal cord injury due to falls from tree stands while hunting. This study's purpose is to systematically characterize and classify those injuries. METHODS: We reviewed the University of Wisconsin Hospital and Clinics' trauma database for tree stand-related injuries from 1999 to 2013...
November 2017: WMJ: Official Publication of the State Medical Society of Wisconsin
Krzysztof M Czajkowski, Anna Pastuszczak, Rafał Kotyński
Single-pixel imaging is an indirect imaging technique which utilizes simplified optical hardware and advanced computational methods. It offers novel solutions for hyper-spectral imaging, polarimetric imaging, three-dimensional imaging, holographic imaging, optical encryption and imaging through scattering media. The main limitations for its use come from relatively high measurement and reconstruction times. In this paper we propose to reduce the required signal acquisition time by using a novel sampling scheme based on a random selection of Morlet wavelets convolved with white noise...
January 11, 2018: Scientific Reports
Özgür Bilgin Topçuoğlu, Özlem Oruç, Sema Saraç, Gülgün Çetintaş Afşar, Kayıhan Uluç
Introduction: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy of the upper extremity. It is usually associated with the compression of the median nerve in the median groove. Because the main symptoms of CTS pain and numbness worsen at night, sleep disorders in CTS patients and the impact of preferred sleeping position on CTS development have been formerly studied. However, to the best of our knowledge, this is the first study assessing the frequency of CTS in obstructive sleep apnea (OSA) patients...
December 2017: Noro Psikiyatri Arsivi
Kelvin Robertson, Laurence A G Marshman, Maria Hennessy, Linton Harriss, David Plummer
BACKGROUND: There is currently an absence of high-grade evidence regarding the treatment of chronic sciatica (CS). Whilst gabapentin (GBP) and pregabalin (PGB) are both currently used to treat CS, equipoise exists regarding their individual use. In particular, no head-to-head study of GBP and PGB in CS exists. Despite equipoise, most countries' formulary regulatory authorities typically favour one drug for subsidy over the other. This hinders interchange wherever the favoured drug is either ineffective or not tolerated...
January 9, 2018: Trials
Monika Bajaj, Girija Natarajan, Seetha Shankaran, Myra Wyckoff, Abbot R Laptook, Edward F Bell, Barbara J Stoll, Waldemar A Carlo, Betty R Vohr, Shampa Saha, Krisa P Van Meurs, Pablo J Sanchez, Carl T D'Angio, Rosemary D Higgins, Abhik Das, Nancy Newman, Michele C Walsh
OBJECTIVES: To describe the frequency and extent of delivery room resuscitation and evaluate the association of delivery room resuscitation with neonatal outcomes in moderately preterm (MPT) infants. STUDY DESIGN: This was an observational cohort study of MPT infants delivered at 290/7 to 336/7 weeks' gestational age (GA) enrolled in the Neonatal Research Network MPT registry. Infants were categorized into 5 groups based on the highest level of delivery room intervention: routine care, oxygen and/or continuous positive airway pressure, bag and mask ventilation, endotracheal intubation, and cardiopulmonary resuscitation including chest compressions and/or epinephrine use...
January 3, 2018: Journal of Pediatrics
C L Poyser, W B York, D Srikanthreddy, B A Glavin, T L Linnik, R P Campion, A V Akimov, A J Kent
Picosecond duration compressive and shear phonon wave packets injected into (311) GaAs slabs transform after propagation through ∼1  mm into chirped acoustic pulses with a frequency increasing in time due to phonon dispersion. By probing the temporal optical response to coherent phonons in a near surface layer of the GaAs slab, we show that phonon chirping opens a transformational route for high-sensitivity terahertz and subterahertz phonon spectroscopy. Temporal gating of the chirped phonon pulse allows the selection of a narrow band phonon spectrum with a central frequency up to 0...
December 22, 2017: Physical Review Letters
Gladys Atinuke Akinseye, Ann-Marie Dickinson, Kevin J Munro
OBJECTIVE: To conduct a systematic review of the benefits of non-linear frequency compression (NLFC) in adults and children. DESIGN: Ten databases were searched for studies comparing the effects of NLFC and conventional processing (CP) for the period January 2008 to September 2017. STUDY SAMPLE: Twelve articles were included in this review: four adults and school-aged only, one pre-school only and three with both adults and school-aged children...
January 3, 2018: International Journal of Audiology
James J Harding, Ghaith Abu-Zeinah, Joanne F Chou, Dwight Hall Owen, Michele Ly, Maeve Aine Lowery, Marinela Capanu, Richard Do, Nancy E Kemeny, Eileen M O'Reilly, Leonard B Saltz, Ghassan K Abou-Alfa
Background: Bone metastases are common in hepatocellular carcinoma (HCC), but their incidence, morbidity, and mortality are not well defined. Methods: The Memorial Sloan Kettering Cancer Center database was queried for all patients with HCC and metastases seen from 2002 to 2014. The prevalence of bone metastasis was determined and cumulative incidence function was used to estimate the probability of developing a bone metastasis. Regression models were created to identify risk factors for osseous metastasis...
January 2018: Journal of the National Comprehensive Cancer Network: JNCCN
Emine Petekkaya, Ahmet Hilmi Yücel, Özgür Sürmelioğlu
Opera and chant singers learn to effectively use aerodynamic components by breathing exercises during their education. Aerodynamic components, including subglottic air pressure and airflow, deteriorate in voice disorders. This study aimed to evaluate the changes in aerodynamic parameters and supraglottic structures of men and women with different vocal registers who are in an opera and chant education program. Vocal acoustic characteristics, aerodynamic components, and supraglottic structures were evaluated in 40 opera and chant art branch students...
December 28, 2017: Journal of Voice: Official Journal of the Voice Foundation
Risha Lane, Amy Harwood, Lorna Watson, Gillian C Leng
BACKGROUND: Exercise programmes are a relatively inexpensive, low-risk option compared with other, more invasive therapies for treatment of leg pain on walking (intermittent claudication (IC)). This is the fourth update of a review first published in 1998. OBJECTIVES: Our goal was to determine whether an exercise programme was effective in alleviating symptoms and increasing walking treadmill distances and walking times in people with intermittent claudication. Secondary objectives were to determine whether exercise was effective in preventing deterioration of underlying disease, reducing cardiovascular events, and improving quality of life...
December 26, 2017: Cochrane Database of Systematic Reviews
Jun Suda, Satoshi Suwa, Shugo Mizuno, Kouki Togo, Yuya Mastuo
Raman images (30μm×30μm×180μm) of a bulk 4H-SiC wafer in contact with a Ni/Au electrode film in 100nm/200nm thick were measured with Micro-Raman spectroscopy at room temperature. As the imaging area approached the interface between the SiC and electrode, the center frequency of the E2(TO) mode (778cm-1) immediately declined; in the Raman imaging, relative distribution of compressive residual stress around residual tensile stress, and linewidth were broadened due to crystal distortion. For LOPC (LO-phonon-plasmon-coupled) mode (970cm-1), center frequency showed variation right next to the interface, while linewidth decreased slowly as the imaging area approached the interface...
December 6, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Amrita Kumari, Ankit Jain, Pooja Hurkat, Ankita Tiwari, Sanjay K Jain
CONTEXT: Microsponge is a novel approach for targeting the drug to the colon for the management of colon ailments such as inflammatory bowel disease. OBJECTIVE: Prednisolone loaded microsponges (PLMs) were prepared and coated with Eudragit S 100 (ES) and evaluated for colon specific drug delivery. MATERIALS AND METHODS: PLMs were prepared using quasi emulsion solvent diffusion technique using ethyl cellulose, triethylcitrate (1% v/v, plasticizer) and polyvinyl alcohol (Mol...
December 20, 2017: Drug Development and Industrial Pharmacy
Jamil Ahmad, Khan Muhammad, Sung Wook Baik
Efficient retrieval of relevant medical cases using semantically similar medical images from large scale repositories can assist medical experts in timely decision making and diagnosis. However, the ever-increasing volume of images hinder performance of image retrieval systems. Recently, features from deep convolutional neural networks (CNN) have yielded state-of-the-art performance in image retrieval. Further, locality sensitive hashing based approaches have become popular for their ability to allow efficient retrieval in large scale datasets...
December 19, 2017: Journal of Medical Systems
E Tian Tan, Keren Sloan, Kokila Lakhoo
A term newborn was referred to our unit with a postnatal diagnosis of a right-sided congenital diaphragmatic hernia (CDH). She was managed with high-frequency oscillatory ventilation, inotropic support, and nitric oxide, with planned surgical repair when she was medically optimized. On day 6 of life, there was an acute deterioration causing difficulty maintaining adequate ventilation and the infant requiring increasing analgesia and paralysis, especially during abdominal examination. A repeat X-ray showed distended bowel loops in the right hemithorax when compared with previous films raising suspicion of bowel obstruction...
January 2017: European Journal of Pediatric Surgery Reports
Dennis J Lee, Charles F LaCasse, Julia M Craven
Channeled spectropolarimetry measures the spectrally resolved Stokes parameters. A key aspect of this technique is to accurately reconstruct the Stokes parameters from a modulated measurement of the channeled spectropolarimeter. The state-of-the-art reconstruction algorithm uses the Fourier transform to extract the Stokes parameters from channels in the Fourier domain. While this approach is straightforward, it can be sensitive to noise and channel cross-talk, and it imposes bandwidth limitations that cut off high frequency details...
December 11, 2017: Optics Express
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