Primordial black hole formation with non-Gaussian curvature perturbations

In the context of transient constant-roll inflation near a local maximum, we derive the non-perturbative field redefinition that relates a Gaussian random field with the true non-Gaussian curvature perturbation. Our analysis shows the emergence of a new critical amplitude $\zeta_*$, corresponding to perturbations that prevent the inflaton from overshooting the local maximum, thus becoming trapped in the false minimum of the potential. For potentials with a mild curvature at the local maximum (and thus small non-Gaussianity), we recover the known perturbative field redefinition. We apply these results to the formation of primordial black holes, and discuss the cases for which $\zeta_*$ is smaller or of the same order than the critical value for collapse of spherically symmetric overdensities. In the latter case, we present a simple potential for which the power spectrum needs an amplitude 10 times smaller that in the Gaussian case for producing a sizeable amount of primordial black holes.Comment: 13 pages, 8 figures. v2: expanded explanations + small changes. v3: small typos correcte

SEEDS - 2018

Contributors include: Nicole F. Anderson, Jenn Lee, Grant Spathis, Ruby David, Martin K. Davis, Mary Thespina Kaltakis, Kat Losacco, Bayley Schendel, Loni Stratch, Allegra Harper, N.R., Kathryn Hudson, Joris Soeding, Christina Chaidez, Vanessa Macias, Trudy Leong, Jennifer King, Joseph Tinaglia, Shirley Vargas, Kellie Jarr, Darka Powers, Alfredo Miranda, Rocio Urbano, Veronica Cerda, Brandi Nevarez, Alexandra Galvanhttps://neiudc.neiu.edu/seeds/1010/thumbnail.jp

Exploring the Black Space of Compressive and Shear Modulus

Uniaxial dynamic modulus is a standard test used to determine the viscoelastic behavior of asphalt pavement materials, with the standard analysis generating a Master Curve. One alternative to the master curve approach is a Black Space diagram, which is a rheological plot that can delineate either dynamic modulus |E*| or shear modulus |G*| vs. phase angle (δ). In this study, four asphalt binders were tested with one aggregate blend. One of these four binders was unmodified and the other three were modified with polymers and acids. Additionally, Polyphosphoric acid (PPA) is compared to the more traditional SBS polymer modification. PPA is currently prohibited in Arkansas because of a lack of information on its field performance. Three tests were performed: Uniaxial |E*|, Indirect Tension (IDT |E*|), and Torsion Bar |G*|. Traditional Master Curves and Black Space diagrams were plotted to have a comparison between all materials. The results show that Black Space diagram plotted with the Torsion Bar |G*| configuration is able to more clearly identify viscoelastic behavior of asphalt pavement materials in comparison with the master curve approach

Evaluation of Fracture Principles in Asphalt Concrete Utilizing the SC(B) Geometry

Since cracking is one of the principal distresses to be considered in asphalt concrete, multiple fracture tests and geometries have been used to quantify cracking resistance. One of the most popular geometries that have been used in fracture tests is the Semi-Circular bend (SC(B)). However, for this geometry, most of the fracture test methods use different parameters such as thickness, testing temperatures, and loading rates. Thus, the purpose of this research was first to evaluate fracture energy by performing a ruggedness test based on ASTM E1169. Then, to apply fracture mechanics concepts to evaluate three specimen thicknesses (25, 50, and 100 mm) and three notch configurations (rectangular, semi-circular and fatigue pre-cracked). Also, with the selected thickness and notch configuration, the concept of time-temperature superposition was applied to characterize cracking in asphalt concrete by using four testing temperatures (-12, 0, 12, and 25 ˚C) and five loading rates (0.03, 0.5, 1.0, 30.0, 50.0 mm/min). The results showed that from the ruggedness test, the fracture energy is significantly influenced by the testing temperatures but not the loading rate. When applying fracture mechanics theories, the selected thickness and notch configuration selected were 50 mm and semi-circular, respectively. Finally, when using time-temperature superposition to plot fracture energy versus the loading rate to mimic the steps followed in the Dynamic Modulus |E*|, a typical sigmoidal was not obtained. However, a parabolic curve was found to better describe the cracking behavior. Utilizing this analysis, the concept of local fracture energy was defined as the peak fracture energy from each set of testing temperatures and loading rates. Using the local fracture energy, the global fracture energy was built and defined as the peak fracture energy from all the testing temperatures plotted. In conclusion, when properly applying fracture mechanics properties and the new concepts of local and global fracture energy, these give a new perspective of how the cracking behavior can be quantified at different testing temperatures independently of the loading rate

Correlación de las Proporciones Intrínsecas de los Incisivos Centrales (IC), Laterales (Il) y Caninos (C) Superiores en Estudiantes Del IX Semestre de la Clínica Odontológica de la U.C.S.M, Arequipa-2017

En el presente trabajo de investigación titulado “Correlación de las proporciones intrínsecas de los incisivos centrales (IC), laterales (IL) y caninos © superiores en estudiantes del IX semestre de la clínica odontológica de la U.C.S.M, Arequipa-2017”. Cuyo objetivo fue analizar el cumplimiento de las proporciones intrínsecas de las piezas, y determinar la correlación de las mismas. Se trata de una investigación descriptiva y correlacional aplicada en una muestra de 52 estudiantes de odontología de la U.C.S.M comprendidos entre 20 y 30 años. Para la recolección de la información se utilizó la técnica de observación directa la que se llevó a cabo mediante una evaluación clínica con una ficha de recolección de datos (diámetros cérvico-incisal y mesio-distal) de cada pieza, con lo cual se pudo obtener las proporciones intrínsecas de los mismos, reforzando la información obtenida con la toma de 5 fotografías por estudiante. Llegándose a las siguientes conclusiones: Un 53,3% de la población en estudio cumple con la proporción intrínseca ideal en el I.C, tanto varones como mujeres, existiendo correlación entre sus diámetros. En los I.L el 71,2% de la población presenta una proporción no ideal aumentada. Tanto en hombres y mujeres, siendo las mujeres las que presentan mayor porcentaje, con ausencia de la correlación entre sus diámetros. En el C el 75% de la población presenta una proporción intrínseca no ideal aumentada, tanto en hombres como mujeres, siendo estas con mayor porcentaje, existiendo una correlación entre sus diámetros. Palabras clave: Proporciones Intrínsecas, Incisivo Centrales, Incisivo Laterales, Caninos

Factors affecting the spatial distribution and breeding habitat of an insular cliff-nesting raptor community

The specific spatial distribution and habitat association—strongly influenced by environmental factors or competitive interactions—are major issues in ecology and conservation. We located and georeferenced nesting sites of five cliff-nesting raptors (Egyptian vulture Neophron percnopterus [a locally extinct species], common buzzard Buteo buteo, osprey Pandion haliaetus, common kestrel Falco tinnunculus, Barbary falcon Falco peregrinus pelegrinoides), and common raven Corvus corax on one of the most biodiverse hotspot within the Canary Islands (Teno, Tenerife). We used generalized linear models to evaluate the factors affecting abundance, richness, and intra- and interspecific interactions. Raptor abundance increased with slope, shrub-covered area, and habitat diversity, and decreased with altitude, and forested and grassed areas. Richness increased with slope and decreased with altitude. Threatened species (osprey, Barbary falcon, and raven) occupied cliffs farther away from houses and roads, and more rugged areas than the non-threatened species. The models suggested that the probability of cliff occupation by buzzards, falcons, and ravens depended only on inter-specific interactions. Buzzard occupation increased with the distance to the nearest raven and kestrel nests, whereas falcons and ravens seek proximity to each other. Teno holds between 75% and 100% of the insular breeding populations of the most endangered species (osprey and raven), indicating the high conservation value of this area. Our study suggests that the preservation of rugged terrains and areas of low human pressure are key factors for raptor conservation and provide basic knowledge on the community structure and habitat associations to develop appropriated management actions for these fragile island populationsPeer reviewe