13,950 research outputs found
Child development - issues in early detection
Child development is a complex, non-linear process affected by multiple factors. In addition, there is a large degree of individual variation.
Developmental delay is present when a child does not reach developmental milestones at the expected age (with adequate leeway for the broad variation among normal children). Although delay may result primarily from a biological factor such as a chromosomal disorder, or an environmental factor such as maternal depression, the principal model for the causes of developmental delay is a ‘transactional’ one. The process of development is viewed as a transaction between the child and the environment, in which each can have profound effects on the other.
About 15% of children have developmental delay. Many, however, are not detected before commencing school, mainly because the disabilities are mild or because they relate to tasks only then attempted by the child. Of the 15%, a much smaller proportion has more severe disability. This group is more likely to present earlier because of the severity of their problems, because there is more often an associated medical condition, and because a number of them (such as those with extreme prematurity) are picked up by at-risk screening programs. 
Detection of recombination in DNA multiple alignments with hidden markov models
CConventional phylogenetic tree estimation methods assume that all sites in a DNA multiple alignment have the same evolutionary history. This assumption is violated in data sets from certain bacteria and viruses due to recombination, a process that leads to the creation of mosaic sequences from different strains and, if undetected, causes systematic errors in phylogenetic tree estimation. In the current work, a hidden Markov model (HMM) is employed to detect recombination events in multiple alignments of DNA sequences. The emission probabilities in a given state are determined by the branching order (topology) and the branch lengths of the respective phylogenetic tree, while the transition probabilities depend on the global recombination probability. The present study improves on an earlier heuristic parameter optimization scheme and shows how the branch lengths and the recombination probability can be optimized in a maximum likelihood sense by applying the expectation maximization (EM) algorithm. The novel algorithm is tested on a synthetic benchmark problem and is found to clearly outperform the earlier heuristic approach. The paper concludes with an application of this scheme to a DNA sequence alignment of the argF gene from four Neisseria strains, where a likely recombination event is clearly detected
Simulating Radiative Magnetohydrodynamical Flows with AstroBEAR: Implementation and Applications of Non-equilibrium Cooling
Radiative cooling plays a crucial role in the dynamics of many astrophysical
flows, and is particularly important in the dense shocked gas within
Herbig-Haro (HH) objects and stellar jets. Simulating cooling processes
accurately is necessary to compare numerical simulations with existing and
planned observations of HH objects, such as those from the Hubble Space
Telescope and the James Webb Space Telescope. In this paper we discuss a new,
non-equilibrium cooling scheme we have implemented into the 3-D
magnetohydrodynamic (MHD) code AstroBEAR. The new cooling function includes
ionization, recombination, and excitation of all the important atomic species
that cool below 10000 K. We tested the routine by comparing its predictions
with those from the well-tested 1-D Cox-Raymond shock code (Raymond 1979). The
results show thatAstroBEAR accurately tracks the ionization fraction,
temperature, and other MHD variables for all low-velocity (.90 km/s) magnetized
radiative shock waves. The new routine allows us to predict synthetic emission
maps in all the bright forbidden and permitted lines observed in stellar jets,
including H{\alpha}, [NII], [OI], and [SII]. We present an example as to how
these synthetic maps facilitate a direct comparison with narrowband images of
HH objects.Comment: 8 figure
A survey of physical education for boys in the public high schools of the state of Rhode Island
Thesis (Ed.M.)--Boston Universit
Non-conformal transformations
Thesis date and author's name handwritten on tpTypescriptM.A. University of Missouri 1907For many years conformal transformations have been studied. Riemann surfaces of many of them have been constructed and their principal properties have been discovered and examined in the study of the theory of functions of a complex variable, for if a transformation is conformal it must satisfy the Cauchy-Riemann equations as will be shown later. Comparatively little, however, has ever been done with conformal transformations. In this paper, we have made a study of some of the properties of such transformations and have constructed Riemann surfaces of a few of them. In Part I, an ordinary conformal transformation has been considered and its Riemann surface constructed. Then by means of non-conformal transformations upon the conformal one, non-conformal transformations between real variables were obtained, and through the properties of the former, the properties of the latter were discovered and the Riemann surfaces were constructed. In Part II, the non-conformal transformations were studied directly
The Millard House
Whitish-grey pre-cast concrete block formed with cruciform-imprinted molds. Wright used the block due to its modular characteristic making it cheap to make and easy to customize.https://openscholarship.wustl.edu/bcs/1150/thumbnail.jp
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