Primordial Black Hole Dark Matter Simulations Using PopSyCLE

Primordial black holes (PBHs), theorized to have originated in the early universe, are speculated to be a viable form of dark matter. If they exist, they should be detectable through photometric and astrometric signals resulting from gravitational microlensing of stars in the Milky Way. Population Synthesis for Compact-object Lensing Events, or PopSyCLE, is a simulation code that enables users to simulate microlensing surveys, and is the first of its kind to include both photometric and astrometric microlensing effects, which are important for potential PBH detection and characterization. To estimate the number of observable PBH microlensing events we modify PopSyCLE to include a dark matter halo consisting of PBHs. We detail our PBH population model, and demonstrate our PopSyCLE + PBH results through simulations of the OGLE-IV and Roman microlensing surveys. We provide a proof-of-concept analysis for adding PBHs into PopSyCLE, and thus include many simplifying assumptions, such as $f_{\text{DM}}$, the fraction of dark matter composed of PBHs, and $\bar{m}_{\text{PBH}}$, mean PBH mass. Assuming $\bar{m}_{\text{PBH}}=30$ $M_{\odot}$, we find $\sim$ 3.65$f_{\text{DM}}$ times as many PBH microlensing events than stellar evolved black hole events, a PBH average peak Einstein crossing time of $\sim$ 91.4 days, estimate on order of $10^2f_{\text{DM}}$ PBH events within the 8 year OGLE-IV results, and estimate Roman to detect on the order of $10^3f_{\text{DM}}$ PBH microlensing events throughout its planned microlensing survey

Forward-Biased Thermal Cycling: A New Module Qualification Test

Following a proposal by BP Solarex to modify the standard module qualification sequence, we performed a forward-biased themal cycling on three types of commercial modules to evaluate the procedure. The total number of thermal cycles was doubled to 400 and maximum power measurements were made every 50 cycles

Numerical Solution of Differential Equations by the Parker-Sochacki Method

A tutorial is presented which demonstrates the theory and usage of the Parker-Sochacki method of numerically solving systems of differential equations. Solutions are demonstrated for the case of projectile motion in air, and for the classical Newtonian N-body problem with mutual gravitational attraction.Comment: Added in July 2010: This tutorial has been posted since 1998 on a university web site, but has now been cited and praised in one or more refereed journals. I am therefore submitting it to the Cornell arXiv so that it may be read in response to its citations. See "Spiking neural network simulation: numerical integration with the Parker-Sochacki method:" J. Comput Neurosci, Robert D. Stewart & Wyeth Bair and http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2717378

Manejo de la Cotorra en Instalaciones Eléctricas en el sur de Florida

La cotorra común (Myiopsitta monachus) es un ave originaria de América del Sur pero se ha establecido en varios sitios a lo largo de los Estados Unidos mediante liberaciones premeditadas y también accidentales. La especie es única entre los loros pues no construye sus nidos en cavidades sino que construye una estructura de nidificación voluminosa con palos. A menudo, tanto en regiones donde es nativa y en los Estados Unidos, la cotorra selecciona las estructuras eléctricas como sitio de nidificación. El material del nido puede causar corto-circuitos que producen daños a la estructura y cortes de luz subsiguientes. En el sur de Florida, el daño causado por las cotorras y los cortes de luz asociados han aumentado substancialmente en los últimos años. Aunque el costo total asociado con el daño y los cortes de luz no se conocen, es evidente que los métodos actuales para manejar el problema son inadecuados. En el 2001, para responder a la necesidad de métodos de manejo más efectivos, la Compañía de Luz y Electricidad de Florida inició un proyecto para identificar e investigar alternativas de manejo nuevas y potencialmente útiles. En este trabajo, revisamos el conocimiento actual sobre los impactos de las cotorras en las estructuras eléctricas y discutimos el estado de la investigación para desarrollar nuevos métodos para reducir estos impactos

Development of cortical shape in the human brain from 6 to 24months of age via a novel measure of shape complexity

The quantification of local surface morphology in the human cortex is important for examining population differences as well as developmental changes in neurodegenerative or neurodevelopmental disorders. We propose a novel cortical shape measure, referred to as the ‘shape complexity index’ (SCI), that represents localized shape complexity as the difference between the observed distributions of local surface topology, as quantified by the shape index (SI) measure, to its best fitting simple topological model within a given neighborhood. We apply a relatively small, adaptive geodesic kernel to calculate the SCI. Due to the small size of the kernel, the proposed SCI measure captures fine differences of cortical shape. With this novel cortical feature, we aim to capture comparatively small local surface changes that capture a) the widening versus deepening of sulcal and gyral regions, as well as b) the emergence and development of secondary and tertiary sulci. Current cortical shape measures, such as the gyrification index (GI) or intrinsic curvature measures, investigate the cortical surface at a different scale and are less well suited to capture these particular cortical surface changes. In our experiments, the proposed SCI demonstrates higher complexity in the gyral/sulcal wall regions, lower complexity in wider gyral ridges and lowest complexity in wider sulcal fundus regions. In early postnatal brain development, our experiments show that SCI reveals a pattern of increased cortical shape complexity with age, as well as sexual dimorphisms in the insula, middle cingulate, parieto-occipital sulcal and Broca's regions. Overall, sex differences were greatest at 6 months of age and were reduced at 24 months, with the difference pattern switching from higher complexity in males at 6 months to higher complexity in females at 24months. This is the first study of longitudinal, cortical complexity maturation and sex differences, in the early postnatal period from 6 to 24 months of age with fine scale, cortical shape measures. These results provide information that complement previous studies of gyrification index in early brain development

A voxel-wise assessment of growth differences in infants developing autism spectrum disorder

Autism Spectrum Disorder (ASD) is a phenotypically and etiologically heterogeneous developmental disorder typically diagnosed around 4 years of age. The development of biomarkers to help in earlier, presymptomatic diagnosis could facilitate earlier identification and therefore earlier intervention and may lead to better outcomes, as well as providing information to help better understand the underlying mechanisms of ASD. In this study, magnetic resonance imaging (MRI) scans of infants at high familial risk, from the Infant Brain Imaging Study (IBIS), at 6, 12 and 24 months of age were included in a morphological analysis, fitting a mixed-effects model to Tensor Based Morphometry (TBM) results to obtain voxel-wise growth trajectories. Subjects were grouped by familial risk and clinical diagnosis at 2 years of age. Several regions, including the posterior cingulate gyrus, the cingulum, the fusiform gyrus, and the precentral gyrus, showed a significant effect for the interaction of group and age associated with ASD, either as an increased or a decreased growth rate of the cerebrum. In general, our results showed increased growth rate within white matter with decreased growth rate found mostly in grey matter. Overall, the regions showing increased growth rate were larger and more numerous than those with decreased growth rate. These results detail, at the voxel level, differences in brain growth trajectories in ASD during the first years of life, previously reported in terms of overall brain volume and surface area

The Emergence of Network Inefficiencies in Infants With Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a developmental disorder defined by behavioural features that emerge during the first years of life. Research indicates that abnormalities in brain connectivity are associated with these behavioural features. However, inclusion of individuals past the age of onset of the defining behaviours complicates interpretation of the observed abnormalities: they may be cascade effects of earlier neuropathology and behavioural abnormalities. Our recent study of network efficiency in a cohort of 24-month-olds at high and low familial risk for ASD reduced this confound; we reported reduced network efficiencies in toddlers classified as ASD. The current study maps the emergence of these inefficiencies in the first year of life

Microsatellite Markers for Red Drum, Sciaenops ocellatus

Polymerase chain reaction (PCR) primers are reported for 68 nuclear-encoded microsatellites developed during the past several years from genomic libraries of red drum (Sciaenops ocelwtus). All68 microsatellites were tested for reproducibility and polymorphism on a sample of five to 12 red drum; 60 of the microsatellites were found to be polymorphic. Estimates of observed and expected heterozygos- ity (gene diversity) and tests of conformity of genotypes to Hardy-Weinberg equi- librium were carried out for a subset of 31 microsatellites on a larger sample of 45 adults provided by Texas Parks and Wildlife. Levels of allelic and gene diversity were average relative to values observed for marine and anadromous fishes. The set of genetic markers should be useful for a variety of studies, including moni- toring and assessment of red drum stock enhancement