Evolution of structure of SiO2 nanoparticles upon cooling from the melt

Evolution of structure of spherical SiO2 nanoparticles upon cooling from the melt has been investigated via molecular-dynamics (MD) simulations under non-periodic boundary conditions (NPBC). We use the pair interatomic potentials which have weak Coulomb interaction and Morse type short-range interaction. The change in structure of SiO2 nanoparticles upon cooling process has been studied through the partial radial distribution functions (PRDFs), coordination number and bond-angle distributions at different temperatures. The core and surface structures of nanoparticles have been studied in details. Our results show significant temperature dependence of structure of nanoparticles. Moreover, temperature dependence of concentration of structural defects in nanoparticles upon cooling from the melt toward glassy state has been found and discussed.Comment: 12 pages, 6 figure

Adaptive Mode Matching in Advanced LIGO and Beyond

The era of gravitational wave astronomy was ushered in by the LIGO (Laser Interferometer Gravitational-Wave Observatory) collaboration with the detection of a binary black hole collision [2]. The event that shook the foundation of space-time allowed mankind to view the cosmos in a way that had never been done previously. Since then, another remarkable event was found by the LIGO and Virgo detectors where two neutron stars collided, sending both gravitational and electromagnetic waves to earth [3]. LIGO was built with the purpose of detecting the ripples in space-time caused by astrophysical events with the hopes of understanding the complexities hidden within the cosmos. In 2011, the primary stages of Advanced LIGO were installed and commissioned to start the first observing run (O1). During the writing of this thesis, the detectors had hardware replaced in order to mitigate noise from scattered light and new optics which reduced the losses from absorption. The upgrades were in preparation for the third observing run (O3) and the work presented here is primarily focused on experimental techniques for operating at higher power and mode matching Gaussian beams in the dual-recycled Michelson interferometer for the Advanced LIGO era and beyond. The first two chapters discuss the fundamentals of gravitational waves and the LIGO detector configurations. The third chapter introduces the reader to fundamentals in mode matching Gaussian laser beams. The fourth and fifth chapter summarizes the author\u27s work at Syracuse University. The sixth chapter deals with work at the LIGO Hanford observatory with an emphasis on mode sensing and high-power operation

Post induced abortion morbidity and mortality in Oleh, Nigeria

The aim of this retrospective study was to determine the maternal morbidity and mortality among 87patient treated at the Central Hospital, Oleh, Delta State, Nigeria, for complications of induced abortion from January 1st 2004 to December 31st 2008. The total number of maternal admissions and deaths, over the period, were, respectively, 3,680 and 34(8 from induced abortion). Induced abortion accounted for 2.4% and 23.5%, respectively, of the total maternal morbidity (admissions) and mortality. The mean age of the patients was 20.4±5.6years (range of 15 –36years). Majority were, in age group 15 – 19years (71.2%), students/young school leavers (85.1%), unmarried (82.8%), unemployed (89.7%) and had had second trimester abortion (64.4%). It is significant that of those who had second trimester abortion, 66.1% were teenagers. Most (94.3%) of the patients presented with multiple complications which included genital sepsis (94.3%), retained products of conception (90.8%), anaemia (17.2%), pelvic infection with peritonitis (17.2%) and abscess formation (15%), uterine (3.5%) and intestinal (2.3%) perforations. The commonest cause of death (n = 8) was generalised septicaemia (37.5%). Policy makers and health managers should formulate initiatives to prevent unwanted pregnancy including health education/contraceptive utilization and provision of safe abortion services. Keywords: abortion, induced, maternal, morbidity, mortality, law

Determinants Of Antenatal Care Services Utilization In Emevor Village, Nigeria

Appropriate ante-natal care services promotes safe-motherhood and delivery with improved maternal and neonatal outcome. The aim of this cross-sectional study was to evaluate the factors influencing the utilization of ante-natal care services in a rural community. Of the 200 women studied, 113 (57%) utilized ante-natal care services during pregnancy while 87 (43%) did not. The difference is not significant (P > 0.05). A majority of the women who attained secondary education (69%), post-secondary education (96%), those whose husbands had secondary education (69%), postsecondary education (82%) and those who had income-yielding occupations (72%) utilized ante-natal care services. While only 36% of full-time housewives, with no other occupation, and 19% of women with a parity of more than 4 children utilized ante-natal care services. It is suggested that low-income, uneducated women with high parity should be targeted for enlightenment; in addition to promoting education of the girl-child and women empowerment. Key words: Ante-natal care, determinants, utilization, rural, Nigeria

The evolution operator of the Hartree-type equation with a quadratic potential

Based on the ideology of the Maslov's complex germ theory, a method has been developed for finding an exact solution of the Cauchy problem for a Hartree-type equation with a quadratic potential in the class of semiclassically concentrated functions. The nonlinear evolution operator has been obtained in explicit form in the class of semiclassically concentrated functions. Parametric families of symmetry operators have been found for the Hartree-type equation. With the help of symmetry operators, families of exact solutions of the equation have been constructed. Exact expressions are obtained for the quasi-energies and their respective states. The Aharonov-Anandan geometric phases are found in explicit form for the quasi-energy states.Comment: 23 pege

Fractional Stochastic Partial Differential Equation for Random Tangent Fields on the Sphere

This paper develops a fractional stochastic partial differential equation (SPDE) to model the evolution of a random tangent vector field on the unit sphere. The SPDE is governed by a fractional diffusion operator to model the L\'{e}vy-type behaviour of the spatial solution, a fractional derivative in time to depict the intermittency of its temporal solution, and is driven by vector-valued fractional Brownian motion on the unit sphere to characterize its temporal long-range dependence. The solution to the SPDE is presented in the form of the Karhunen-Lo\`{e}ve expansion in terms of vector spherical harmonics. Its covariance matrix function is established as a tensor field on the unit sphere that is an expansion of Legendre tensor kernels. The variance of the increments and approximations to the solutions are studied and convergence rates of the approximation errors are given. It is demonstrated how these convergence rates depend on the decay of the power spectrum and variances of the fractional Brownian motion.Comment: 20 page

Braking and Body Angles Control of an Insect-Computer Hybrid Robot by Electrical Stimulation of Beetle Flight Muscle in Free Flight

While engineers put lots of effort, resources, and time in building insect scale micro aerial vehicles (MAVs) that fly like insects, insects themselves are the real masters of flight. What if we would use living insect as platform for MAV instead? Here, we reported a flight control via electrical stimulation of a flight muscle of an insect-computer hybrid robot, which is the interface of a mountable wireless backpack controller and a living beetle. The beetle uses indirect flight muscles to drive wing flapping and three major direct flight muscles (basalar, subalar and third axilliary (3Ax) muscles) to control the kinematics of the wings for flight maneuver. While turning control was already achieved by stimulating basalar and 3Ax muscles, electrical stimulation of subalar muscles resulted in braking and elevation control in flight. We also demonstrated around 20 degrees of contralateral yaw and roll by stimulating individual subalar muscle. Stimulating both subalar muscles lead to an increase of 20 degrees in pitch and decelerate the flight by 1.5 m/s2 as well as an induce an elevation of 2 m/s2.Comment: 9 pages, 7 figures, supplemental video: https://youtu.be/P9dxsSf14LY . Cyborg and Bionic Systems 202

Supporting 3rd-grade students’ model-based explanations about groundwater: A quasi-experimental study of a curricular intervention

Scientific modelling is a key practice in which K-12 students should engage to begin developing robust conceptual understanding of natural systems, including water. However, little past research has explored primary students’ learning about groundwater, engagement in scientific modelling, and/or the ways in which teachers conceptualize and cultivate model-based science learning environments. We are engaged in a multi-year project designed to support 3rd-grade students’ formulation of model-based explanations (MBE) for hydrologic phenomenon, including groundwater, through curricular and instructional support. In this quasi-experimental comparative study of five 3rd-grade classrooms, we present findings from analysis of students’ MBE generated as part of experiencing a baseline curricular intervention (Year 1) and a modelling-enhanced curricular intervention (Year 2). Findings show that students experiencing the latter version of the unit made significant gains in both conceptual understanding and reasoning about groundwater, but that these gains varied by classroom. Overall, student gains from Year 1 to Year 2 were attributed to changes in two of the five classrooms in which students were provided additional instructional supports and scaffolds to enhance their MBE for groundwater. Within these two classrooms, the teachers enacted the Year 2 curriculum in unique ways that reflected their deeper understanding about the practices of modelling. Their enactments played a critical role in supporting students’ MBE about groundwater. Study findings contribute to research on scientific modelling in elementary science learning environments and have important implications for teachers and curriculum developers

Multifractal scaling of products of birth--death processes

We investigate the scaling properties of products of the exponential of birth--death processes with certain given marginal discrete distributions and covariance structures. The conditions on the mean, variance and covariance functions of the resulting cumulative processes are interpreted in terms of the moment generating functions. We provide four illustrative examples of Poisson, Pascal, binomial and hypergeometric distributions. We establish the corresponding log-Poisson, log-Pascal, log-binomial and log-hypergeometric scenarios for the limiting processes, including their R\'{e}nyi functions and dependence properties.Comment: Published in at http://dx.doi.org/10.3150/08-BEJ156 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

Fractional-in-time and multifracational-in-space stochastic partial differential equations

This paper derives the weak-sense Gaussian solution to a family of fractional-in-time and multifractional-in-space stochastic partial differential equations, driven by fractional-integrated-in-time spatiotemporal white noise. Some fundamental results on the theory of pseudodifferential operators of variable order, and on the Mittag-Leffler function are applied to obtain the temporal, spatial and spatiotemporal H¨older continuity, in the mean-square sense, of the derived solution