4,154 research outputs found

    Compensation of Beer-Lambert attenuation using non-diffracting Bessel beams

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    We report on a versatile method to compensate the linear attenuation in a medium, independently of its microscopic origin. The method exploits diffraction-limited Bessel beams and tailored on-axis intensity profiles which are generated using a phase-only spatial light modulator. This technique for compensating one of the most fundamental limiting processes in linear optics is shown to be efficient for a wide range of experimental conditions (modifying the refractive index and the attenuation coefficient). Finally, we explain how this method can be advantageously exploited in applications ranging from bio-imaging light sheet microscopy to quantum memories for future quantum communication networks

    DEVELOPING A PREDICTIVE MODEL FOR PROSTATE CANCER SCREENING INTENT

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    African Americans bear a disproportionately high burden of cancer incidence and mortality in this country. The purpose of this dissertation was to investigate factors associated with African-American men, who are incarcerated, making informed health decisions about participation in prostate cancer screening, as well as exploring factors that reduce modifiable risk factors for cancer. The United States incarcerates more people per capita than any country in the world and African American men are overrepresented in the U.S. prison system This dissertation is composed of three manuscripts. The first paper reviews the current literature about the factors that influence African-American males in making informed decisions about whether to participate in prostate cancer screening. The second paper uses existing data from a sample of 129 incarcerated African American men to examine the value of an intervention aimed at reducing modifiable risks for cardiovascular disease – and by extension, cancer – in inmates. The third paper explores predictors of intent to screen (or not) for prostate cancer in incarcerated African-American males, as well as those factors that influence informed decision-making in this population. These papers provide an overview of factors that influence incarcerated African-American men’s health decisions (health literacy, having a relative with previous diagnosis). These findings can be used to guide future research that addresses African-American male decision-making about personal health outcomes

    The Meaning and Malleableness of Liberty from 1897-1945

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    This paper covers how the substance and meaning of liberty changed during the ending years of the Gilded Age (1870-1900) through the beginning ages of the Civil Rights Movement (1954-1968). Economic liberty took shape in the cases Allegeyer v. Louisiana (1897) and Lochner v. New York (1905). Civil liberties would take several more years to come into the Supreme Court’s jurisdiction. The case Gitlow v. New York (1925) began the establishment of incorporation of the Bill of Rights to the states, otherwise known as our fundamental liberties (note: The Supreme Court used selective incorporation, however). In the case U.S. v. Carolene Products (1938), the court stated that it would impose higher scrutiny to laws that violated the Bill of Rights. This paper attempts to rationalize that legal realism and sociological jurisprudence, both established by Roscoe Pound, changed the way we view liberty in the modern day. In a span of just under 50 years, the court retreated from substantive Due Process of economic liberty to substantive Due Process of civil liberty and human rights. Rulings such as Korematsu v. U.S. (1945), which established strict scrutiny, were the stepping stones of the growing Civil Rights Movement that would take the nation by storm from the mid-1950s until the end of the 1960s. Lastly, this paper argues that, while it may not be publicly known to all, Supreme Court decisions shape the way our laws are created, and thus, how our democratic society functions as a whole. We must not take our liberty for granted

    Dormancy in the Seed of Western Wheatgrass (Agropyron smithii, Rydb.)

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    As is the case with many of the native grass species, western wheatgrass can at times possess a high amount of seed dormancy. This dormancy makes the determination of pure live seed difficult. Consequently, laboratory methods have been sought to completely break this dormancy in order to obtain a true determination of seed viability. Such methods as embryo excision, lemma and plea removal, caryopsis clipping, alternating temperatures, and others have been used with varying success. The method now employed by the South Dakota State Seed Laboratory to determine the viability of ungerminated grass seeds is the tetrazolium test. After the 28-day germination period, the ungerminated seeds are bisected longitudinally and placed in 1.0% tetrazolium solution for four hours. At the end of that period the seeds which have red or pink embryos are considered dormant seeds. The rest are considered dead. The purpose of this study was to attempt to determine the possible cause of the induction of dormancy in western wheatgrass seeds and assess the effects of alternate seed treatment methods on the breaking of this dormancy

    Deciding to Buy: Civil-Military Relations and Major Weapons Programs

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    The development and procurement of major weapons programs in the United States is a complex and often drawn-out process complicated by political considerations and often sharp disagreements over requirements and the merits of systems. Secretaries of Defense since Robert McNamara have sought to impose discipline on the process, with varying degrees of success. Conflicts between a Military Service and the civilian leadership are inevitable. A Service wants to develop the most advanced system to address its perceived need, whereas the Secretary of Defense must balance competing requirements across the Department of Defense. The military and the civilian leadership may also have different strategic perspectives that feed this conflict. Through the detailed analysis of three case studies—the Nuclear Surface Navy in the 1960s, the B-1 Bomber in the 1970s, and the Crusader Artillery System in the 2000s--the author explores some of the common themes and sources of friction that arise in civil-military relations concerning major weapons programs. He concludes with some thoughts on how the Secretary of Defense can anticipate and reduce these sources of friction, while retaining an environment that supports healthy debate.https://press.armywarcollege.edu/monographs/1338/thumbnail.jp

    An analysis of mixed integer linear sets based on lattice point free convex sets

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    Split cuts are cutting planes for mixed integer programs whose validity is derived from maximal lattice point free polyhedra of the form S:={x:π0πTxπ0+1}S:=\{x : \pi_0 \leq \pi^T x \leq \pi_0+1 \} called split sets. The set obtained by adding all split cuts is called the split closure, and the split closure is known to be a polyhedron. A split set SS has max-facet-width equal to one in the sense that max{πTx:xS}min{πTx:xS}1\max\{\pi^T x : x \in S \}-\min\{\pi^T x : x \in S \} \leq 1. In this paper we consider using general lattice point free rational polyhedra to derive valid cuts for mixed integer linear sets. We say that lattice point free polyhedra with max-facet-width equal to ww have width size ww. A split cut of width size ww is then a valid inequality whose validity follows from a lattice point free rational polyhedron of width size ww. The ww-th split closure is the set obtained by adding all valid inequalities of width size at most ww. Our main result is a sufficient condition for the addition of a family of rational inequalities to result in a polyhedral relaxation. We then show that a corollary is that the ww-th split closure is a polyhedron. Given this result, a natural question is which width size ww^* is required to design a finite cutting plane proof for the validity of an inequality. Specifically, for this value ww^*, a finite cutting plane proof exists that uses lattice point free rational polyhedra of width size at most ww^*, but no finite cutting plane proof that only uses lattice point free rational polyhedra of width size smaller than ww^*. We characterize ww^* based on the faces of the linear relaxation

    Ten Simple Rules for a Successful Collaboration

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