5,145 research outputs found

    Drones or no drones, the violence will continue in Pakistan

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    Speaking from Islamabad, U.S. Secretary of State John Kerry recently hinted at the possibility of ending the use of the drone in Pakistan. Reflecting an earlier speech by President Obama at the National Defense University in Washington, DC, Secretary Kerry stated, “I think the programme will end as we have eliminated most of the threat and continue to eliminate it.” He continued, “I think the President has a very real timeline and we hope it’s going to be very, very soon.

    Field Guide to Nonindigenous Marine Fishes of Florida

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    The purpose of this field guide is to provide information on nonindigenous (i.e., non-native) fishes that have been observed in Florida’s marine waters. Introductions of non-native marine fishes into Florida’s waters could be intentional or unintentional, and are likely from a variety of sources, including aquarium releases, escape from aquaculture, loss due to extreme weather events (e.g., flooding from hurricanes), and possibly transfer with ballast water or hull-fouling. Presently the lionfishes (Pterois volitans and P. miles) are the only non-native marine fish species known to be established along the coast of Florida. All other marine fishes in this guide (except the euryhaline species, see below) have infrequent occurrences, occur singly or in small groups, and have not yet become self-sustaining populations. Aquarium releases are one of the major pathways whereby nonindigenous fishes gain access to new environments (Ruiz et al. 1997; Fuller et al. 1999). Most of the nonindigenous marine fishes found in Florida’s waters are thought to be aquarium fishes that either were illegally released into the ocean or escaped captivity (e.g., during severe storm/flooding events). Indeed, south Florida is a hotspot for nonindigenous marine aquarium fishes (Semmens et al. 2004). Increased public awareness of the problems caused by released or escaped aquarium fishes may aid in stemming the frequency of releases. For example, HabitattitudeTM (www.habitattitude.net) is a national public awareness and partnership campaign that encourages aquarists and water gardeners to prevent the release of unwanted aquarium plants, fish and other animals. It prompts hobbyists to adopt alternative actions when dealing with these aquatic plants and animals. (PDF file contains 133 pages.

    “Miss, Miss, Look at What My Mother Sent Me from Jail”

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    When I tell people that I teach in a public school, especially when I go on to say that I teach at the Junior High level there is almost aIways snickering sounds and rolling eyes followed by horror stories from the past. They relate memories of crowded, noisy hallways filled with bullies; classrooms that felt like jail, teachers that were bored and lots of hormone driven mis-adventures. I just smile because I know it is all too true. I do not attempt to explain why, as an artist, I choose to return to the classroom after so many years or how I am inspired everyday by the energy and truth of the students I encounter. I have come to learn that this immediate reaction by others is only a small part of the whole experience

    Shock-compressed MgSiO_3 glass, enstatite, olivine, and quartz: Optical emission, temperatures, and melting

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    Optical emission of MgSiO_3 glass, enstatite, olivine, and quartz under shock wave compression was investigated with optical pyrometry at discrete wavelengths ranging from visible to near infrared. We develop a new analysis of optical emission that does not require a gray body assumption. Instead, at each wavelength, the optical linear absorption coefficients (α) and blackbody spectral radiances (L_(λb)) of shocked and unshocked materials were obtained by nonlinear fitting to the time-resolved radiance from the target assembly. The absorption spectra of unshocked samples corresponding to the measured values of α reproduce those from independent static optical spectroscopic measurements. The measured values of α (ranging from 7 to 56 mm^(−1)) for shocked samples indicate that shock-induced high-pressure phases (including melt) can be regarded essentially as black bodies in the optical range investigated, although starting phases such as enstatite and olivine have band-like spectra at ambient conditions. The effect of emission from the air gap at the driver sample interface on the recorded radiance can be resolved, but α and L_(λb) cannot be separated for this component of the signal. The shock velocity-particle velocity relationships of these silicates derived from radiance history are in accord with previous investigations using independent techniques. Given the limited amount of shock wave data, possible high-pressure melting curves of Mg-perovskite and its assemblage with periclase are deduced; their melting temperatures near the core-mantle boundary (CMB) being 6000 ± 500 K and 4000 ± 300 K, respectively. It is proposed that Mg-perovskite melts with density increase at the CMB pressure

    Shock-induced melting of MgSiO_3 perovskite and implications for melts in Earth's lowermost mantle

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    New shock wave equation of state (EOS) data for enstatite and MgSiO_3 glass constrain the density change upon melting of Mg-silicate perovskite up to 200 GPa. The melt becomes denser than perovskite near the base of Earth's lower mantle. This inference is confirmed by shock temperature data suggesting a negative pressure-temperature slope along the melting curve at high pressure. Although melting of Earth's mantle involves multiple phases and chemical components, this implies that the partial melts invoked to explain anomalous seismic velocities in the lowermost mantle may be dynamically stable

    Superradiant lasing from J-aggregated molecules adsorbed onto colloidal silver

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    Cataloged from PDF version of article.The picosecond time-resolved emission spectrum of the cyanine dye 1,18-diethyl-3,38- bis-~3-sulfopropyl!-5,58,6,68-tetrachlorobenzimidazolocarbocyanine ~also known as BIC! adsorbed onto colloidal silver was examined as a function of laser pulse energy at room temperature. BIC is found to aggregate on colloidal silver, and the number of coherently responding molecules involved in the one-exciton state ~i.e., the coherence length! was estimated to involve 8–9 molecules. Lasing at a remarkably low incident pulse energy threshold was found for this system and explained in terms of a mechanism involving superradiant states created in coherently coupled adsorbed molecules that emit photons which stimulate emission from other spatially distributed superradiant states. © 1998 American Institute of Physics

    Dynamic compression of SiO_2: A new interpretation

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    In light of recent discoveries of post-stishovite phases of SiO_2, with the CaCl_2 and α-PbO_2 structures, we have reassigned the regimes along the Hugoniots for initial quartz, coesite, cristobalite, porous coesite, and fused silica. Calculated Hugoniots for fused silica, cristobalite and porous coesite indicate transition to stishovite, and then melt. Hugoniots for crystal quartz and coesite indicate that transition occurs to stishovite, then the CaCl2 structure and finally to melt

    Prospective Policy Analysis of the Kentucky HEALTH Demonstration Waiver

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    In January 2018, the Centers for Medicare & Medicaid Services approved Kentucky’s Section 1115 Medicaid demonstration waiver, which gave the state approval to require work/community engagement as a condition of Medicaid eligibility, charge premiums of up to 4% household income, and add an incentive account for dental and vison services. The waiver projected nearly 100,000 fewer enrollees and $2.4 billion less in spending over the five-year demonstration period. Two days short of the waiver July 1st implementation date a federal judge ruled the waiver invalid. This finding held that the Health and Human Services Secretary’s judgement was arbitrary and capricious. This capstone project was a prospective policy analysis to determine the potential impact of the Kentucky HEALTH demonstration waiver and assess alternatives to the policy. A criteria-alternatives matrix was used to evaluate the policy alternatives. The most viable policy option at this time is for the state to continue Medicaid expansion. While the results are subjective the analytic method can be adjusted as data becomes available
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