1,428 research outputs found

    Sophomore Student Spirituality

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    The second year of college, with its unique challenges, has been found to present students with issues that could possibly make it more difficult than the first year. Some students experience the sophomore slump, which is defined in a myriad of ways, including reduced motivation and the uncertainty that comes with choosing a major. One major result of the slump is attrition between the sophomore and junior years. This study looks at the spiritual life of sophomores that experienced some aspect of the sophomore slump at a private, Christian liberal arts institution. It specifically looks at how they experienced the slump as well as their spiritual experiences during the sophomore year

    Intermediate Wakimoto modules for Affine sl(n+1)

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    We construct certain boson type realizations of affine sl(n+1) that depend on a parameter r. When r=0 we get a Fock space realization of Imaginary Verma modules appearing in the work of the first author and when r=n they are the Wakimoto modules described in the work of Feigin and Frenkel

    Solution of the Roth-Marques-Durian Rotational Abrasion Model

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    We solve the rotational abrasion model of Roth, Marques and Durian (arXiv:1009.3492), a one-dimensional quasilinear partial differential equation resembling the inviscid Burgers equation with the unusual feature of a step function factor as a coefficient. The complexity of the solution is primarily in keeping track of the cases in the piecewise function that results from certain amputation and interpolation processes, so we also extract from it a model of an evolving planar tree graph that tracks the evolution of the coarse features of the contour.Comment: 5 pages, 4 figure

    Measurement of the Target-Normal Single-Spin Asymmetry in Quasielastic Scattering from the Reaction ³He↑(e, e\u27)

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    We report the first measurement of the target single-spin asymmetry, Ay, in quasielastic scattering from the inclusive reaction ³He↑(e, e\u27) on a ³He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero Ay can arise from the interference between the one-and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q2 = 0.13, 0.46, and 0.97 GeV2. These measurements demonstrate, for the first time, that the 3He asymmetry is clearly nonzero and negative at the 4σ-9σ level. Using measured proton-to-3He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q2 is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q2 = 0.97 GeV2 agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions

    Topological modes bound to dislocations in mechanical metamaterials

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    Mechanical metamaterials are artificial structures with unusual properties, such as negative Poisson ratio, bistability or tunable vibrational properties, that originate in the geometry of their unit cell. At the heart of such unusual behaviour is often a soft mode: a motion that does not significantly stretch or compress the links between constituent elements. When activated by motors or external fields, soft modes become the building blocks of robots and smart materials. Here, we demonstrate the existence of topological soft modes that can be positioned at desired locations in a metamaterial while being robust against a wide range of structural deformations or changes in material parameters. These protected modes, localized at dislocations, are the mechanical analogue of topological states bound to defects in electronic systems. We create physical realizations of the topological modes in prototypes of kagome lattices built out of rigid triangular plates. We show mathematically that they originate from the interplay between two Berry phases: the Burgers vector of the dislocation and the topological polarization of the lattice. Our work paves the way towards engineering topologically protected nano-mechanical structures for molecular robotics or information storage and read-out.Comment: 13 pages, 6 figures; changes to text and figures and added analysis on mode localization; see http://www.lorentz.leidenuniv.nl/~paulose/dislocation-modes/ for accompanying video

    Scalable SCPPM Decoder

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    A decoder was developed that decodes a serial concatenated pulse position modulation (SCPPM) encoded information sequence. The decoder takes as input a sequence of four bit log-likelihood ratios (LLR) for each PPM slot in a codeword via a XAUI 10-Gb/s quad optical fiber interface. If the decoder is unavailable, it passes the LLRs on to the next decoder via a XAUI 10-Gb/s quad optical fiber interface. Otherwise, it decodes the sequence and outputs information bits through a 1-GB/s Ethernet UDP/IP (User Datagram Protocol/Internet Protocol) interface. The throughput for a single decoder unit is 150-Mb/s at an average of four decoding iterations; by connecting a number of decoder units in series, a decoding rate equal to that of the aggregate rate is achieved. The unit is controlled through a 1-GB/s Ethernet UDP/IP interface. This ground station decoder was developed to demonstrate a deep space optical communication link capability, and is unique in the scalable design to achieve real-time SCPP decoding at the aggregate data rate

    Flux-Enabled Exploration of the Role of Sip1 in galactose yeast metabolism

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    13C metabolic flux analysis (13C MFA) is an important systems biology technique that has been used to investigate microbial metabolism for decades. The heterotrimer Snf1 kinase complex plays a key role in the preference Saccharomyces cerevisiae exhibits for glucose over galactose, a phenomenon known as glucose repression or carbon catabolite repression. The SIP1 gene, encoding a part of this complex, has received little attention, presumably, because its knockout lacks a growth phenotype. We present a fluxomic investigation of the relative effects of the presence of galactose in classically glucose-repressing media and/or knockout of SIP1 using a multi-scale variant of 13C MFA known as 2-Scale 13C metabolic flux analysis (2S-13C MFA). In this study, all strains have the galactose metabolism deactivated (gal1Δ background) so as to be able to separate the metabolic effects purely related to glucose repression from those arising from galactose metabolism. The resulting flux profiles reveal that the presence of galactose in classically glucose-repressing conditions, for a CEN.PK113-7D gal1Δ background, results in a substantial decrease in pentose phosphate pathway (PPP) flux and increased flow from cytosolic pyruvate and malate through the mitochondria toward cytosolic branched-chain amino acid biosynthesis. These fluxomic redistributions are accompanied by a higher maximum specific growth rate, both seemingly in violation of glucose repression. Deletion of SIP1 in the CEN.PK113-7D gal1Δ cells grown in mixed glucose/galactose medium results in a further increase. Knockout of this gene in cells grown in glucose-only medium results in no change in growth rate and a corresponding decrease in glucose and ethanol exchange fluxes and flux through pathways involved in aspartate/threonine biosynthesis. Glucose repression appears to be violated at a 1/10 ratio of galactose-to-glucose. Based on the scientific literature, we may have conducted our experiments near a critical sugar ratio that is known to allow galactose to enter the cell. Additionally, we report a number of fluxomic changes associated with these growth rate increases and unexpected flux profile redistributions resulting from deletion of SIP1 in glucose-only medium

    The Occurrence of Uterine Benign Diseases and their Histomorphologic Characters

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    Uterine diseases are several and can develop from any part of the organ. Noticeable benign diseases are type called hydatidiform mole considered benign among gestational trophoblastic disease and is said to occur from abnormal fertilization of abnormal ova. Other forms are inflammatory, proliferative of insidious cell/tissue implant, hormonal induced, and infectious in their origin. Samples were obtained from patients consulted and admitted into Department of Morbid Anatomy of Ebonyi State University Teaching Hospital. Clinical and histopathological record books were reviewed alongside processed tissues, and slides stained by popular heamatoxylin and eosin technique in the 3 year study period. Of the 642 gynecological samples searched, result showed a progressive increase in number as the years empty from 2011 to 2013 presenting 8 uterine diseases in a population of 116 cases. A total of 518 cases were product of conception of which 250 were as a result of incomplete spontaneous abortions and 200 inappropriate criminal abortions, while 68 could not be associated with any definite cause. Leiomyoma cases were 75%, uterine/vaginal prolapsed were 6%, molar pregnancies and endometriosis 5% and while endometrial hyperplasia and uterine atrophy were 3% each and 2% each were for uterine polyp and adenomyosis in all of the 116 cases. Six age groups were involved showing that 7 diseases and total frequency of 50% occurred with age group (40-49) and is seconded by (30-39) which had 5 conditions with frequency of 21%. Attempted provisional diagnosis was based on clinical presentations, and of 116 cases 80% were confirmed accurate by laboratory diagnosis. Clinical characters of leiomyomas were the same while histomorphologic features were not entirely consistently same in all
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