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Search Results: 1 - 10 of 499039 matches for " Andrew S R "
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The Versatility of Acellular Fetal Bovine Dermal Matrix for Head and Neck Surgical Reconstruction in Children  [PDF]
Jeremiah C. Tracy, William S. Kim, Andrew R. Scott
International Journal of Clinical Medicine (IJCM) , 2014, DOI: 10.4236/ijcm.2014.518143
Abstract: Objectives: To describe the versatility of acellular fetal bovine dermal matrix as an alternative to human cadaveric allograft for head and neck reconstructive procedures in children. Study Design: Case series with chart review. Methods: A database of pediatric operative procedures was queried for the use of acellular fetal bovine dermal matrix over a 16-month period. Indications for reconstruction were assessed and initial parental and surgeon satisfaction with the product were noted. Results: During the time period of 3/2012 and 7/2013 a total of 8 reconstructive procedures were performed on pediatric patients using acellular fetal bovine dermal matrix. Indications for use varied and included open and transnasal endoscopic repair of encephaloceles and soft tissue reconstructions including lateral pharyngeal wall repair, cleft palate repair, and facial recontouring operations. Acellular fetal bovine dermal matrix had a subjectively increased ease of use as compared to the surgeon’s prior experience with human cadaveric acellular dermis. Every parent vocalized a greater comfort level with the use of a bovine product over the alternative of human cadaveric tissue. The cost of acellular fetal bovine dermal matrix is slightly lower than the cost of human cadaveric acellular dermis. Conclusions: Acellular fetal bovine dermal matrix appears to be an acceptable alternative to human cadaveric acellular dermis for various forms of head and neck soft tissue reconstruction in children. Further prospective studies are warranted to assess for any differences in the long-term efficacy of this product as compared to other forms of allograft reconstruction.
KARAKTERISASI BIJI DAN PROTEIN KORO KOMAK (Lablab purpureus (L) Sweet) SEBAGAI SUMBER PROTEIN [Characterization of Hyacinth Bean (Lablab purpureus (L.) Sweet) Seed and Its Protein]
Andrew S R,Wiwiek S W,Subagio
Jurnal Teknologi dan Industri Pangan , 2006,
Abstract: This research aimed to characterize the physiochemical properties of hyacinth beans as new protein source. The result of research showed that hyacinth beans are oval shaped and orange and yellow coloured. The edible part of hyacinth beans is 83.2 ± 1.1 % of dry seed; in which the carbohydrate is 67.9 ± 1.1 %; protein: 17.1 ± 1.5 % and fat: 1.1 ± 0.4 %. According to their solubility, the protein fractions were found as albumin: 18.22 %; globuli : 55.15 % and glutelin : 26.13 %, whereas prolamin was not detected. Further analyis showed that, the globulin is consisted of globulin 7S (3.50%) and globulin 11S (0.67 %). The hyacinth beans are potential to be used for protein source.
Panmixia postponed: ancestry-related assortative mating in contemporary human populations
Andrew S Burrell, Todd R Disotell
Genome Biology , 2009, DOI: 10.1186/gb-2009-10-11-245
Abstract: The past 500 years have been characterized by unprecedented episodes of human migration and admixture, particularly in the Americas. Technological innovations have to a certain extent reduced the impact of geography on human behavior, raising the possibility of a truly global population. At a local level, however, geographic, demographic, linguistic, cultural and even legal barriers now, and in the past, limit and circumscribe human mate choices. For example, cultural biases towards patrilocal or matrilocal marriage (where the married couple set up home in the place of origin of the man or woman, respectively) can lead to the differential structuring of male or female genetic variation [1]. Caste systems can similarly lead to the stratification of genetic structure within societies [2]. The patterns of divergence and admixture that characterize human populations are the result of complex cultural and evolutionary processes, but can also negatively influence the outcomes of biomedical studies associating disease susceptibilities and other biomedical traits with particular genes [3].In this context, a paper by Risch et al. [4] in Genome Biology is especially interesting in that they used 'ancestry informative markers' (AIMs) to document the genetic signature of assortative mating in contemporary human populations. These genetic markers document the contribution of particular ancestral groups to an individual's genetic make-up. Surprisingly, in view of the fact that such ancestral contributions may not be physically obvious or even known to the individual or their intended spouse, Risch et al. find that ancestral make-up is positively correlated with spouse choice within both populations studied, but find no correlation with socioeconomic or geographic origins that might explain the correlation. The work raises interesting questions about the cultural factors influencing human population genomic structure as well as the evolutionary and biomedical significance of such
MRI structural findings in schizophrenia
Gilbert Andrew R,Keshavan Matcheri S
Revista Brasileira de Psiquiatria , 2001,
Viable inflationary models ending with a first-order phase transition
Marina Cortês,Andrew R. Liddle
Physics , 2009, DOI: 10.1103/PhysRevD.80.083524
Abstract: We investigate the parameter space of hybrid inflation models where inflation terminates via a first-order phase transition causing nucleation of bubbles. Such models experience a tension from the need to ensure nearly scale invariant density perturbations, while avoiding a near scale-invariant bubble size distribution which would conflict observations. We perform an exact analysis of the different regimes of the models, where the energy density of the inflaton field ranges from being negligible as compared to the vacuum energy to providing most of the energy for inflation. Despite recent microwave anisotropy results favouring a spectral index less than one, we find that there are still viable models that end with bubble production and can match all available observations. As a by-product of our analysis, we also provide an up-to-date assessment of the viable parameter space of Linde's original second-order hybrid model across its full parameter range.
Halo Substructure And The Power Spectrum
Andrew R. Zentner,James S. Bullock
Physics , 2003, DOI: 10.1086/378797
Abstract: (ABRIDGED) We present a semi-analytic model to explore merger histories, destruction rates, and survival probabilities of substructure in dark matter halos and use it to study the substructure populations of galaxy-sized halos as a function of the power spectrum. We successfully reproduce the subhalo velocity function and radial distribution seen in N-body simulations for standard LCDM. We explore the implications of spectra with normalizations and tilts spanning sigma_8 = 0.65-1 and n = 0.8-1. We also study a running index (RI) model with dn/dlnk=-0.03, as discussed in the first year WMAP report, and several WDM models with masses m_W = 0.75, 1.5, 3.0 keV. The substructure mass fraction is relatively insensitive to the tilt and overall normalization of the power spectrum. All CDM-type models yield projected substructure mass fractions that are consistent with, but on the low side of, estimates from strong lens systems: f = 0.4-1.5% (64 percentile) in systems M_sub < 10^9 Msun. Truncated models produce significantly smaller fractions and are disfavored by lensing results. We compare our predicted subhalo velocity functions to the dwarf satellite population of the Milky Way. Assuming isotropic velocity dispersions, we find the standard n=1 model overpredicts the number of MW satellites as expected. Models with less small-scale power are more successful because there are fewer subhalos of a given circular velocity and the mapping between observed velocity dispersion and halo circular velocity is markedly altered. The RI model, or a fixed tilt with sigma_8=0.75, can account for the MW dwarfs without the need for differential feedback; however, these comparisons depend sensitively on the assumption of isotropic velocities in satellite galaxies.
Second-Order Reconstruction of the Inflationary Potential
Andrew R Liddle,Michael S Turner
Physics , 1994, DOI: 10.1103/PhysRevD.54.2980
Abstract: To first order in the deviation from scale invariance the inflationary potential and its first two derivatives can be expressed in terms of the spectral indices of the scalar and tensor perturbations, $n$ and $n_T$, and their contributions to the variance of the quadrupole CBR temperature anisotropy, $S$ and $T$. In addition, there is a ``consistency relation'' between these quantities: $n_T= -{1\over 7}{T\over S}$. We discuss the overall strategy of perturbative reconstruction and derive the second-order expressions for the inflationary potential and its first two derivatives and the first-order expression for its third derivative, all in terms of $n$, $n_T$, $S$, $T$, and $dn/d\ln k$. We also obtain the second-order consistency relation, $n_T =-{1\over 7}{T\over S}[1+0.11{T\over S} + 0.15 (n-1)]$. As an example we consider the exponential potential, the only known case where exact analytic solutions for the perturbation spectra exist. We reconstruct the potential via Taylor expansion (with coefficients calculated at both first and second order), and introduce the Pad\'{e} approximant as a greatly improved alternative.
Dark halo densities, substructure, and the initial power spectrum
James S. Bullock,Andrew R. Zentner
Physics , 2002, DOI: 10.1016/S0920-5632(03)02091-7
Abstract: Although the currently favored cold dark matter plus cosmological constant model for structure formation assumes an n=1 scale-invariant initial power spectrum, most inflation models produce at least mild deviations from n=1. Because the lever arm from the CMB normalization to galaxy scales is long, even a small ``tilt'' can have important implications for galactic observations. Here we calculate the COBE-normalized power spectra for several well-motivated models of inflation and compute implications for the substructure content and central densities of galaxy halos. Using an analytic model, normalized against N-body simulations, we show that while halos in the standard (n=1) model are overdense by a factor of ~6 compared to observations, several of our example inflation+LCDM models predict halo densities well within the range of observations, which prefer models with n ~ 0.85. We go on to use a semi-analytic model (also normalized against N-body simulations) to follow the merger histories of galaxy-sized halos and track the orbital decay, disruption, and evolution of the merging substructure. Models with n ~0.85 predict a factor of ~3 fewer subhalos at a fixed circular velocity than the standard $n = 1$ case. Although this level of reduction does not resolve the ``dwarf satellite problem'', it does imply that the level of feedback required to match the observed number of dwarfs is sensitive to the initial power spectrum. Finally, the fraction of galaxy-halo mass that is bound up in substructure is consistent with limits imposed by multiply imaged quasars for all models considered: f_sub > 0.01 even for an effective tilt of n ~0.8.We conclude that, at their current level, lensing constraints of this kind do not provide strong limits on the primordial power spectrum.
Halo Substructure and the Power Spectrum
Andrew R. Zentner,James S. Bullock
Physics , 2002, DOI: 10.1063/1.1581785
Abstract: In this proceeding, we present the results of a semi-analytic study of CDM substructure as a function of the primordial power spectrum. We apply our method to several tilted models in the LCDM framework with n=0.85-1.1, sigma_8=0.65-1.2 when COBE normalized. We also study a more extreme, warm dark matter-like spectrum that is sharply truncated below a scale of 10^10 h^-1 Msun. We show that the mass fraction of halo substructure is not a strong function of spectral slope, so it likely will be difficult to constrain tilt using flux ratios of gravitationally lensed quasars. On the positive side, all of our CDM-type models yield projected mass fractions in good agreement with strong lensing estimates: f \sim 1.5% at M \sim 10^8 Msun. The truncated model produces a significantly smaller fraction, f \lsim 0.3%, suggesting that warm dark matter-like spectra may be distinguished from CDM spectra using lensing. We also discuss the issue of dwarf satellite abundances, with emphasis on the cosmological dependence of the map between the observed central velocity dispersion of Milky Way satellites and the maximum circular velocities of their host halos. In agreement with earlier work, we find that standard LCDM over-predicts the estimated count of Milky Way satellites at fixed Vmax by an order of magnitude, but tilted models do better because subhalos are less concentrated. Interestingly, under the assumption that dwarfs have isotropic velocity dispersion tensors, models with significantly tilted spectra (n \lsim 0.85, sigma_8 \lsim 0.7) may under-predict the number of large Milky Way satellites with Vmax \gsim 40 km/s.
Cosmic microwave background anomalies in an open universe
Andrew R Liddle,Marina Cortês
Physics , 2013, DOI: 10.1103/PhysRevLett.111.111302
Abstract: We argue that the observed large-scale cosmic microwave anomalies, discovered by WMAP and confirmed by the Planck satellite, are most naturally explained in the context of a marginally-open universe. Particular focus is placed on the dipole power asymmetry, via an open universe implementation of the large-scale gradient mechanism of Erickcek et al. Open inflation models, which are motivated by the string landscape and which can excite `super-curvature' perturbation modes, can explain the presence of a very-large-scale perturbation that leads to a dipole modulation of the power spectrum measured by a typical observer. We provide a specific implementation of the scenario which appears compatible with all existing constraints.
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