Optical and Hybrid Imaging and Processing for Big Data Problems

(First paragraph) The scientific community has been dealing with big data for a long time. Due to advancement in sensing, networking, and storage technology, other domains such as business, health, and social media followed. Data are considered the gold of the 21st century and are being collected, stored, and analyzed at a rapid pace. The amount of data being collected creates a compelling case for investing in hardware and software research to support generating even more data from new sensors and with better quality. It also creates a compelling case for investing in research and development of new hardware and software for data analytics. This special section of Optical Engineering explores the optical and hybrid imaging and processing technology that will enable capturing and analyzing large amounts of data or help stream the data for further exploration and analysis

Knowledge, sources of information, and risk factors for sexually transmitted infections among secondary school youth in Zaria, Northern Nigeria

Background: Sexually transmitted infections (STIs) are responsible for a variety of health problems especially among the youth who engage in risky sexual behavior. There are few studies that describe STIs among the youths in Northern Nigeria. The objective of the study was to assess knowledge of STIs and risk factors among secondary school youth. Materials and Methods: This was a cross‑sectional study in which structured, self‑administered questionnaire was used to collect data on socio‑demographics, knowledge on STIs, and risk factors. Three senior secondary schools were purposively selected for the study. Results: A total of 1765 youths aged 10‑30 years with mean age of 16.9 ± 2.0 years participated in the study. 1371 (77.7%) and 394 (22.3%) were respectively Muslim and Christian. Mean age at first sexual intercourse was 16.7 ± 2.0 years.A majority (67.6%) of them heard about STIs; sources of information of STIs were school lessons 23.6%, mass media 23.3%, and health magazines 19.2%, respectively. Generally, knowledge on STIs was good as 75.4% of respondents knew how the disease is transmitted. This knowledge was significantly associated with class of student, place of treatment, and religious teaching (χ2 = 9.6, P = 0.047, χ2 = 22.1, P = 0.035 and 42.6, P = 0.001, respectively). Mean knowledge score was 0.698 ± 0.01. A majority of respondents were engaged in risky sexual behavior as only 16.2% use condom as a preventive measure. Eleven percent reported ever having an STI in the past and majority (52.8%) go to government hospital for treatment of acquired STI. 56% of the youth had two or more boy/girl friends and 30% had sexual relationships. Conclusion: It was concluded that secondary school youth had good knowledge about STIs; however, the opposite is true when it comes to preventive practice (use of condom). Interventions such as periodic publicity awareness and school seminars focusing on STI preventions are needed to control the disease among the youth

Posterior fixation including the fractured vertebra in short segment fixation of unstable thoracolumbar junction burst fractures

The aim of this study was to evaluate the efficacy of inclusion of the fractured vertebra in short segment fixation in terms of clinical and the radiological outcomes in unstable thoracolumbar junction burst fractures at a minimum of 1 year follow-up. Records of 52 patients (age: 21-50 years) with thoracolumbar burst fracture (T10L2) in Magerl Type A fractures underwent posterior pedicle screw fixation including the fractured vertebra. Clinical parameters were back pain using Visual Analogue Score (VAS) and disability using Oswestry disability index (ODI), neurological deficit (using ASIA grade) and radiologic parameters (Cobb angle, the kyphotic deformation and vertebral height) were measured before surgery and at 3, 6 and 12 months  post-operatively. The presence of screw breakage, screw pullout, peri-implant loosening, and rod breakage were considered as criteria for implant failure. The majority of fractures resulted due to falls (31 cases), and the remaining cases resulted from car accidents (21 cases). The fractured vertebral body level was L1, T12, L2, T11, and T10 in 23, 17, 6, 4 and 2 cases and achieved satisfactory clinical outcomes according to the modified Mcnab criteria 18, 25, 6 and 3 cases were considered to have excellent, good, fair, and poor outcome. The mean kyphotic angle at pre-, post-operative and final follow-up was 13.5 ± 6.3, 13.4 ± 4.3, 8.5 ± 6.  The average loss of kyphosis correction was 6.4 ± 5.2° at the final follow-up. The mean pre- and post-operative kyphotic deformation of vertebral body was 5.1 ± 3.2, 4.8 ± 2.3 and at final follow-up was 4.5 ± 4.0 (p>0.05). The mean anterior and posterior vertebral height also showed significant improvements post-operatively, which were maintained at the final follow-up. The mean ODI and VAS scores at the end of 1 year were 17.4%, 1.7 respectively. There was no case of major complication after surgery and during the follow-up period. In conclusion, reduction of unstable thoracolumbar junction burst fracture can be achieved and maintained with the use of short-segment pedicle screw fixation including the fractured vertebra, avoiding the need for anterior reconstruction.

Simulating the Effect of Friction on Drive Screw Using System-of-System Modeling with Predetermined Torque

In most mechanical systems, screw threads serve three main basic purposes: (i) to transmit power, (ii) to provide a clamping force, and finally (iii) to restrict or control motion. This chapter demonstrates the effects of friction and behavior which can occur in a bolted fastening (screw thread) for advanced design purposes. To model this behavior, other control components are attached to the bolted screw. The bolt preload is applied with a predetermined torque. For this case the preload depends on the friction under the head and in the thread. The friction prevents the loosing of the bolted fastening. This effect is termed as self-locking effect. We designed an algorithm that reproduces an exemplary simulation scenario, which determines friction and its effect on thread angle based on the strength of the coefficient of friction at a specific tension or clamp load value using the system-of-system approach. The result shows specific behavior on both the motion in threads and drive screw with predetermined torque. The chapter is limited to creating a simple simulation environment to demonstrate the effects

Knowledge, determinants and use of modern contraceptives among married women in Sabon Gari Zaria, Northern Nigeria

Introduction: Improving reproductive health of young women in least developed countries requires access to safe and effective contraceptive methods. We conducted a study on knowledge, determinants and use of modern contraceptives among married women in Sabon Gari, Zaria-Northern Nigeria. Objective : The study aimed to assess contraceptive knowledge, sources of information, determinants and use of modern FP. Methods: This was a cross sectional descriptive and health facility-based study. Respondents were selected consecutively from the out-patient clinic register of Comprehensive Health Centre, ABUTH Sabon Gari, Zaria. A structured questionnaire was used to collect data. Results: Only 309 questionnaires were finally analyzed. Mean age of respondents was 32.8 +/9.6 years. Majority (78%) were Muslim, married and in monogamous union (72.2%). Knowledge of modern FP was almost universal 97.7% even though knowledge of two or more methods was 55.3%. Mean number of contraceptives known by respondents was 2. About 42.7% of respondents have ever used any contraceptive method. The Contraceptive Prevalence Rate (CPR) was 15.2% and the preferred FP choice among respondents was the injectable contraceptives (5.2%). Sources of information on FP were Nurse 42.1% and relatives/friends 19.7%. Significant determinants of FP current use among the respondents include the age, education, occupation, religion and choice of the respondents ( P < 0.05). Conclusions: FP use among study participants attending the centre is low despite good knowledge of modern contraception. Factors associated with contraceptive use should be used by all tiers of Government to organize sustained publicity awareness campaigns in order to improve acceptability and usage

Image processing and control of a programmable spatial light modulator for spatial beam shaping

Abstract not provide

A programmable beam shaping system for tailoring the profile of high fluence laser beams

Customized spatial light modulators have been designed and fabricated for use as precision beam shaping devices in fusion class laser systems. By inserting this device in a low-fluence relay plane upstream of the amplifier chain, 'blocker' obscurations can be programmed into the beam profile to shadow small isolated flaws on downstream optical components that might otherwise limit the system operating energy. In this two stage system, 1920 x 1080 bitmap images are first imprinted on incoherent, 470 nm address beams via pixilated liquid crystal on silicon (LCoS) modulators. To realize defined masking functions with smooth apodized shapes and no pixelization artifacts, address beam images are projected onto custom fabricated optically-addressable light valves. Each valve consists of a large, single pixel liquid cell in series with a photoconductive Bismuth silicon Oxide (BSO) crystal. The BSO crystal enables bright and dark regions of the address image to locally control the voltage supplied to the liquid crystal layer which in turn modulates the amplitude of the coherent beams at 1053 nm. Valves as large as 24 mm x 36 mm have been fabricated with low wavefront distortion (&lt;0.5 waves) and antireflection coatings for high transmission (&gt;90%) and etalon suppression to avoid spectral and temporal ripple. This device in combination with a flaw inspection system and optic registration strategy represents a new approach for extending the operational lifetime of high fluence laser optics

Programmable beam spatial shaping system for the National Ignition Facility

A system of customized spatial light modulators has been installed onto the front end of the laser system at the National Ignition Facility (NIF). The devices are capable of shaping the beam profile at a low-fluence relay plane upstream of the amplifier chain. Their primary function is to introduce 'blocker' obscurations at programmed locations within the beam profile. These obscurations are positioned to shadow small, isolated flaws on downstream optical components that might otherwise limit the system operating energy. The modulators were designed to enable a drop-in retrofit of each of the 48 existing Pre Amplifier Modules (PAMs) without compromising their original performance specifications. This was accomplished by use of transmissive Optically Addressable Light Valves (OALV) based on a Bismuth Silicon Oxide photoconductive layer in series with a twisted nematic liquid crystal (LC) layer. These Programmable Spatial Shaper packages in combination with a flaw inspection system and optic registration strategy have provided a robust approach for extending the operational lifetime of high fluence laser optics on NIF