Spin(7)-Manifolds as Generalized Connected Sums and 3d N=1 Theories

M-theory on compact eight-manifolds with $\mathrm{Spin}(7)$-holonomy is a framework for geometric engineering of 3d $\mathcal{N}=1$ gauge theories coupled to gravity. We propose a new construction of such $\mathrm{Spin}(7)$-manifolds, based on a generalized connected sum, where the building blocks are a Calabi-Yau four-fold and a $G_2$-holonomy manifold times a circle, respectively, which both asymptote to a Calabi-Yau three-fold times a cylinder. The generalized connected sum construction is first exemplified for Joyce orbifolds, and is then used to construct examples of new compact manifolds with $\mathrm{Spin}(7)$-holonomy. In instances when there is a K3-fibration of the $\mathrm{Spin}(7)$-manifold, we test the spectra using duality to heterotic on a $T^3$-fibered $G_2$-holonomy manifold, which are shown to be precisely the recently discovered twisted-connected sum constructions.Comment: 49 pages, 4 figures; v2: added reference

Communities as allies

A popular axiom attributed to British policing is the police are the public and the public are the police. Inherent in this term is a blurring of the distinction between the police and the public they serve; the police are cast as being little different from the citizenry and citizens are cast into a role of responsibility for the safety and well-being of the community. In effect, communities are framed as allies in the fight to ensure safe and secure neighborhoods. Across space and time this idea has held uneven sway within American policing ideologies. This essay considers the relationship between the police and the policed, as well as how that relationship might be influenced be technological and social evolutions. The essay begins with an overview of the very notion of ―community‖ and their relationship with crime and disorder. This is followed by a brief review of the historical trajectory of police-community interactions within American policing. We then consider how emerging and future technologies might modify what ―community‖ means. The essay concludes with a consideration of police and community interactions and partnerships in the digital age

Bad moon on the rise? Lunar cycles and incidents of crime

Popular cultures in Western societies have long espoused the notion that phases of the moon influence human behavior. In particular, there is a common belief the full moon increases incidents of aberrant, deviant, and criminal behavior. Using police, astronomical, and weather data from a major southwestern American city, this study assessed whether lunar cycles related with rates of reported crime. The findings fail to support popular lore, which has suggested that lunar phase influenced the volume of crime reported to the police. Future research directions examining qualitative rather than quantitative aspects of this problem may yield further inform the understanding of whether lunar cycles appreciably influence demands for policing services

Antiferromagnetic interactions in single crystalline Zn1-xCoxO thin films

In a rather contradictory situation regarding magnetic data on Co-doped ZnO, we have succeeded in fabricating high-quality single crystalline Zn1-xCoxO (x=0.003-0.07) thin films. This gives us the possibility, for the first time, to examine the it intrinsic magnetic properties of ZnO:Co at a quantitative level and therefore to address several unsolved problems, the major one being the nature of the Co-Co interaction in the ZnO structure.Comment: 4 pages, 4 figures,accepted for publication in PR

The Environmental Kuznets Curve Under a New framework: Role of Social Capital in Water Pollution

We advance a case for an inclusion of social capital in the environmental Kuznets curve analysis using highly disaggregated data on water pollution in Louisiana. A social capital index and other variables are used in parametric and spatial panel regression models to explain water pollution dynamics.Environmental Economics and Policy,

An Ecological Assessment of Property and Violent Crime Rates Across a Latino Urban Landscape: The Role of Social Disorganization and Institutional Anomie Theory

The present research put forth an integrated theoretical framework aimed at providing a more holistic community- level approach explaining crime across a heavily populated Latino city. Guided by social disorganization and institutional anomie theory, this study used several data sources and OLS regression techniques to examine the impact of social disorganization, economic and noneconomic institutional characteristics on rates of property and violent crime across 1,016 census block groups in San Antonio, Texas. While several findings emerged, interactions between alcohol density and concentrated disadvantage were significant and positively associated with property and violent crime. Interactions between welfare generosity and concentrated disadvantage were significant and negatively associated with the outcomes

Helping Students Achieve Their Goals : The Experience of Working with Students with Mental Health Concerns in a Residence Hall

Individuals living with a mental health issue and attending college may experience significant opportunities for growth and also personal challenges in their development into young adulthood. Residence hall directors may be instrumental in assisting this population during their college years. The purpose of this qualitative study was to examine the experience of residence hall directors working specifically with students with mental health concerns. Grounded in Relational-Cultural-Theory and Chickering’s Student Developmental Theory this study was a two phase study conducted at universities and colleges in the northeast United States. Utilizing a basic qualitative approach deductive coding was used to examine the data. The findings are discussed and implications for practice and further research are included

Influence of Phase Matching on the Cooper Minimum in Ar High Harmonic Spectra

We study the influence of phase matching on interference minima in high harmonic spectra. We concentrate on structures in atoms due to interference of different angular momentum channels during recombination. We use the Cooper minimum (CM) in argon at 47 eV as a marker in the harmonic spectrum. We measure 2d harmonic spectra in argon as a function of wavelength and angular divergence. While we identify a clear CM in the spectrum when the target gas jet is placed after the laser focus, we find that the appearance of the CM varies with angular divergence and can even be completely washed out when the gas jet is placed closer to the focus. We also show that the argon CM appears at different wavelengths in harmonic and photo-absorption spectra measured under conditions independent of any wavelength calibration. We model the experiment with a simulation based on coupled solutions of the time-dependent Schr\"odinger equation and the Maxwell wave equation, including both the single atom response and macroscopic effects of propagation. The single atom calculations confirm that the ground state of argon can be represented by its field free $p$ symmetry, despite the strong laser field used in high harmonic generation. Because of this, the CM structure in the harmonic spectrum can be described as the interference of continuum $s$ and $d$ channels, whose relative phase jumps by $\pi$ at the CM energy, resulting in a minimum shifted from the photoionization result. We also show that the full calculations reproduce the dependence of the CM on the macroscopic conditions. We calculate simple phase matching factors as a function of harmonic order and explain our experimental and theoretical observation in terms of the effect of phase matching on the shape of the harmonic spectrum. Phase matching must be taken into account to fully understand spectral features related to HHG spectroscopy