Sources of Guns to Dangerous People: What We Learn By Asking Them

Gun violence exacts a lethal toll on public health. This paper focuses on reducing access to firearms by dangerous offenders, contributing original empirical data on the gun transactions that arm offenders in Chicago. Conducted in the fall of 2013, analysis of an open-ended survey of 99 inmates of Cook County Jail focuses on a subset of violence-prone individuals with the goal of improving law enforcement actions. Among our principal findings:Our respondents (adult offenders living in Chicago or nearby) obtain most of their guns from their social network of personal connections. Rarely is the proximate source either direct purchase from a gun store, or theft.Only about 60% of guns in the possession of respondents were obtained by purchase or trade. Other common arrangements include sharing guns and holding guns for others.About one in seven respondents report selling guns, but in only a few cases as a regular source of income.Gangs continue to play some role in Chicago in organizing gun buys and in distributing guns to members as needed.The Chicago Police Department has a considerable effect on the workings of the underground gun market through deterrence. Transactions with strangers and less-trusted associates are limited by concerns over arrest risk (if the buyer should happen to be an undercover officer or a snitch), and about being caught with a "dirty" gun (one that has been fired in a crime)

Knudsen gas provides nanobubble stability

We provide a model for the remarkable stability of surface nanobubbles to bulk dissolution. The key to the solution is that the gas in a nanobubble is of Knudsen type. This leads to the generation of a bulk liquid flow which effectively forces the diffusive gas to remain local. Our model predicts the presence of a vertical water jet immediately above a nanobubble, with an estimated speed of $\sim3.3\,\mathrm{m/s}$, in good agreement with our experimental atomic force microscopy measurement of $\sim2.7\,\mathrm{m/s}$. In addition, our model also predicts an upper bound for the size of nanobubbles, which is consistent with the available experimental data

The atmospheric effects of stratospheric aircraft: A topical review

In the late 1960s the aircraft industry became interested in developing a fleet of supersonic transports (SSTs). Between 1972 and 1975, the Climatic Impact Assessment Program (CIAP) studied the possible environmental impact of SSTs. For environmental and economic reasons, the fleet of SSTs was not developed. The Upper Atmosphere Research Program (UARP) has recently undertaken the responsibility of directing scientific research needed to assess the atmospheric impact of supersonic transports. The UARP and the High-Speed Research Program asked Harold Johnston to review the current understanding of aircraft emissions and their effect on the stratosphere. Johnston and his colleagues have recently re-examined the SST problem using current models for stratospheric ozone chemistry. A unique view is given here of the current scientific issues and the lessons learned since the beginning of CIAP, and it links the current research program with the assessment process that began two years ago

The construction and evaluation of a word pronunciation test for grades four, five, and six

Thesis (Ed.M.)--Boston Universit

Surface bubble nucleation phase space

Recent research has revealed several different techniques for nanoscopic gas nucleation on submerged surfaces, with findings seemingly in contradiction with each other. In response to this, we have systematically investigated the occurrence of surface nanobubbles on a hydrophobised silicon substrate for various different liquid temperatures and gas concentrations, which we controlled independently. We found that nanobubbles occupy a distinct region of this phase space, occurring for gas concentrations of approximately 100-110%. Below the nanobubble phase we did not detect any gaseous formations on the substrate, whereas micropancakes (micron wide, nanometer high gaseous domains) were found at higher temperatures and gas concentrations. We moreover find that supersaturation of dissolved gases is not a requirement for nucleation of bubbles.Comment: 4 pages, 4 figure

Report of the panel on lithospheric structure and evolution, section 3

The panel concluded that NASA can contribute to developing a refined understanding of the compositional, structural, and thermal differences between continental and oceanic lithosphere through a vigorous program in solid Earth science with the following objectives: determine the most fundamental geophysical property of the planet; determine the global gravity field to an accuracy of a few milliGals at wavelengths of 100 km or less; determine the global lithospheric magnetic field to a few nanoTeslas at a wavelength of 100 km; determine how the lithosphere has evolved to its present state via acquiring geologic remote sensing data over all the continents

Effect of estrogen on manganese-induced toxicity on embryonic astrocytes

Manganese (Mn) is a natural trace metal that is essential for many physiological functions in the human body. Astrocytes in the central nervous system are susceptible reservoirs for Mn accumulation. Estrogen, a steroidal hormone, has been shown to mitigate Mn-induced toxicity in cultures of postnatal astrocytes. However, differences in expression/inducibility of glutamate transporters and glutamine synthetase, transmitters, and the natural gonadal steroids and their receptors are known to occur in astrocyte cultures derived from various stages of fetal and postnatal development. Cultures of embryonic (E18) hippocampal astrocytes were examined in this study for the ability of 17 β-estradiol (E2) to protect them from Mn toxicity by up regulating gene expression of a glutamate transporter. Primary rat hippocampal astrocytes were pretreated with β-Estradiol (E2) in vitro and subsequently, Mn sulfate (MnSO4). The amount of toxic damage to the astrocytes was measured by quantifying glial fibrillary acidic protein (GFAP) with a sandwiched Enzyme-Linked Immunosorbent Assay (ELISA). ELISA analysis indicated Mn exposure at 100 μM, 300 μM, or 600 μM significantly increased GFAP levels. However, E2 concentrations at 10 nM or 30 nM significantly reduced Mn-induced GFAP concentrations at 100 μM. Cells pretreated with 10 nM or 30 nM of E2 significantly lowered GFAP levels. The Water-Soluble Tetrazolium-8 (WST-8) method was utilized to determine cell viability. The WST-8 assay showed that Mn concentrations of 100 μM, 300 μM, or 600 μM significantly reduced the dehydrogenase activity, thereby decreasing the number of viable astrocytes. Enzyme activity with 600 μM of Mn was significantly decreased when compared with 100 μM of Mn, revealing a dose-dependent effect. However, the dehydrogenase activity in cells treated with 600 μM Mn was significantly increased when pretreated with 10 nM of E2. Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) was used to measure changes in glutamate transporter-1 gene expression in astrocytes after pretreatment of E2 and subsequently, Mn. PCR analysis showed that when cells were exposed to 300 μM Mn, the GLT-1 gene expression was reduced compared to the control. Data also showed that the GLT-1 mRNA was upregulated in cells pretreated with 10 nM E2. When the cells were pretreated with 10 nM E2 and subsequently, 300 μM Mn, there was an increase in the GLT-1 gene expression. The experimental results indicate that E2 can attenuate some Mn-induced toxicity in E18 astrocytes