6,599 research outputs found

    Preferences of fourth grade children for certain social studies activities.

    Full text link
    Thesis (Ed.M.)--Boston Universit

    The Relevance of Relevance: Section 215 of the USA PATRIOT Act and the NSA Metadata Collection Program

    Get PDF
    In June 2013, a National Security Agency (NSA) contractor, Edward Snowden, leaked classified documents exposing a number of secret government programs. Among these programs was the “telephony metadata” collection program under which the government collects records from phone companies containing call record data for nearly every American. News of this program created considerable controversy and led to a wave of litigation contesting the validity of the program. The legality of the metadata collection program has been challenged on both constitutional and statutory grounds. The program derives its authority from Section 215 of the USA PATRIOT Act, codified as 50 U.S.C. § 1861. The statute requires that there be reasonable grounds to believe the data collected is “relevant to an authorized investigation.” The government deems all these records “relevant” based on the fact that they are used to find patterns and connections in preventing terrorist activity. Critics of the program, however, assert that billions of records cannot possibly be relevant when a negligible portion of those records are actually linked to terrorist activity. This Note examines the conflicting interpretations of “relevant,” and concludes that while the current state of the law permits bulk data collection, the power of the NSA to collect records on such a large scale must be reined in

    The Rise of Computerized High Frequency Trading: Use and Controversy

    Get PDF
    Over the last decade, there has been a dramatic shift in how securities are traded in the capital markets. Utilizing supercomputers and complex algorithms that pick up on breaking news, company/stock/economic information and price and volume movements, many institutions now make trades in a matter of microseconds, through a practice known as high frequency trading. Today, high frequency traders have virtually phased out the dinosaur floor-traders and average investors of the past. With the recent attempted robbery of one of these high frequency trading platforms from Goldman Sachs this past summer, this rise of the machines has become front page news, generating vast controversy and discourse over this largely secretive and ultra-lucrative practice. Because of this phenomenon, those of us on Main Street are faced with a variety of questions: What exactly is high frequency trading? How does it work? How long has this been going on for? Should it be banned or curtailed? What is the end-game, and how will this shape the future of securities trading and its regulation? This iBrief explores the answers to these questions

    Using abundance data to assess the relative role of sampling biases and evolutionary radiations in Upper Muschelkalk ammonoids

    Get PDF
    The Middle Triassic ammonoid genus Ceratites diversified spectacularly within the Germanic Muschelkalk Basin during the Anisian/Ladian (244–232 Mya). Previous studies have interpreted this diversification as a sequence of rapid, endemic radiations from a few immigrant taxa. Here we investigate the possibility that geological and sampling biases, rather than ecological and evolutionary processes, are responsible for this pattern. A new specimen based dataset of Ceratites species-richness and abundance was assembled. This dataset was combined with 1:200000 geological maps in a geodatabase to facilitate geospatial analyses. One set of analyses compared species richness per geological map with the number of occurrences and localities per map. Per-map change in the amount of rock available to sample for fossils was also included as a variable. Of these three variables, number of occurrences is the most strongly correlated with richness. Variation in the amount of rock is not a strong determinant of species-richness. However, rarefaction of basin-wide species/abundance data demonstrates that differences in species-richness through time are not attributable to sample size differences. The average percent similarity among sites remained close to 50% throughout the Upper Muschelkalk. The rank abundance distribution (RAD) of species from the first interval of the Upper Muschelkalk is consistent with colonization of a disturbed environment, while the other two intervals have RADs consistent with more stable ecosystems. These results indicate that genuine ecological and evolutionary events are partly responsible for the observed differences in richness and abundance. Although changes in the RADs through time support changes in the ammonoid assemblage structure, the processes underlying increasing richness and change in RADS cannot be explained by increasing geographic distinctiveness or isolation among the ammonoid assemblages present at different localities

    Stress intensity factors for deep cracks emanating from the corner formed by a hole intersecting a plate surface

    Get PDF
    A technique consisting of freezing photo-elasticity and a numerical method was used to obtain stress intensity factors for natural cracks emanating from the corner at which a hole intersects a plate surface. Geometries studied were: (1) crack depth to thickness ratios of approximately 0.2, (2) 0.5 and 0.75; (3) crack depth to crack length ratios of approximately 1.0 to 2.0; and (4) crack length to hole radius ratios of about 0.5 to 2.0. All final crack geometries were grown under monotonic loading and growth was not self similar, with most of the growth occuring through the thickness under remote extension. Stress intensity factors were determined at the intersection of the flaw border

    Stress intensity factors for deep cracks emanating from the corner formed by a hole intersecting a plate surface

    Get PDF
    A technique consisting of a marriage between stress freezing photoelasticity and a numerical method was used to obtain stress intensity factors for natural cracks emanating from the corner at which a hole intersects a plate surface. Geometrics studied were: crack depth to thickness ratios of approximately 0.2, 0.5, and 0.75; crack depth to crack length ratios of approximately 1.0 to 2.0. All final crack geometries were grown under monotonic loading and growth was not self similar with most of the growth occurring through the thickness under remote extension. Stress intensity plate surface K sub s factors were determined at the intersection of the flaw border with the plate surface K sub s and with the edge of the hole K sub h. Results showed that for the relatively shallow flaws K sub h approximately equal to 1.5 K sub s, for the moderately deep flaws K sub h approximately equal to K sub s, and for the deep flaws K sub h approximately equal to 0.5 K sub s, revealing a severe sensitivity of K to flaw geometry

    A plane strain analysis of the blunted crack tip using small strain deformation plasticity theory

    Get PDF
    A deformation plasticity analysis of the tip region of a blunted crack in plane strain is presented. The power hardening material is incompressible both elastically and plastically, in order to simulate behavior of a stress freezing material above critical temperature. Stress and displacement fields surrounding the crack tip are presented. The results indicate that the maximum stress seen at the crack tip is indeed limited and is determined by the tensile properties; however, the scale over which the stresses act is dependent on the loading. Comparisons are good between the forward crack tip displacement and micro-fractographic measurments of stretch zones observed in plane strain fracture toughness tests

    A comparison of theory and practice in market intelligence gathering for Australian micro-businesses and SMEs

    Get PDF
    Recent government sponsored research has demonstrated that there is a gap between the theory and practice of market intelligence gathering within the Australian micro, small and medium businesses (SMEs). Typically, there is a significant amount of information in literature about 'what needs to be done', however, there is little insight in terms of how market intelligence gathering should occur. This paper provides a novel insight and a comparison between the theory and practices of market intelligence gathering of micro-business and SMEs in Australia and demonstrates an anomoly in so far as typically the literature does not match what actually occurs in practice. A model for market intelligence gathering for micro-businesses and SMEs is also discussed

    A comparison of theory and practice in market intelligence gathering for Australian micro-businesses and SMEs

    Get PDF
    Recent government sponsored research has demonstrated that there is a gap between the theory and practice of market intelligence gathering within the Australian micro, small and medium businesses (SMEs). Typically, there is a significant amount of information in literature about 'what needs to be done', however, there is little insight in terms of how market intelligence gathering should occur. This paper provides a novel insight and a comparison between the theory and practices of market intelligence gathering of micro-business and SMEs in Australia and demonstrates an anomoly in so far as typically the literature does not match what actually occurs in practice. A model for market intelligence gathering for micro-businesses and SMEs is also discussed
    • 

    corecore