Thirring Solitons in the presence of dispersion

The effect of dispersion or diffraction on zero-velocity solitons is studied for the generalized massive Thirring model describing a nonlinear optical fiber with grating or parallel-coupled planar waveguides with misaligned axes. The Thirring solitons existing at zero dispersion/diffraction are shown numerically to be separated by a finite gap from three isolated soliton branches. Inside the gap, there is an infinity of multi-soliton branches. Thus, the Thirring solitons are structurally unstable. In another parameter region (far from the Thirring limit), solitons exist everywhere.Comment: 12 pages, Latex. To appear in Phys. Rev. Let

Life Around the Hyphen: Inherited Legacies and Their Impact on How We Teach, Write and Talk about Exile/Immigrant Experiences

The Exile Studies Program In Collaboration with: The Betsy-South Beach Hotel The Department of English The College of Arts, Sciences & Education Panel Discussionhttps://digitalcommons.fiu.edu/cri_events/1327/thumbnail.jp

Geotechnical characterization of an innovative soil stabilization product (Aggrebind/Road Master) usable in the construction, rehabilitation and maintenance of road infrastructure and the construction of social housing in Cameroon

Building roads in developing countries has always been very expensive. An efficient and more affordable method is needed. AggreBind’s soil stabilization solutions, known as RoadMaster (RM1 / RM2) and AggreBind (AGB-WT/BT) are offered. The objective of the present study was to make a geotechnical characterization of this product with a view towards its use in the construction, rehabilitation and maintenance of road infrastructure in Cameroon.A series of laboratory tests were carried out; soil identification tests (particle size analysis, Atterberg limits), lift tests (Proctor and modified CBR test), determination of the optimum water content of the material, maximum dry density, immediate CBR index and the CBR index after immersion for 4 days.Only the 95% OPM CBR test was carried out on the soil with the additive AGB-WT/RM1 in order to characterize the effects of the product on the soil.In conclusion, AggreBind/RoadMaster can provide stable, dust-free roads and stabilized base courses for general roads and highways that meet or exceed the bearing capacity requirements of international road specifications. In addition, the use of this product reduces the cost of road construction by 40% to60% and increases in-situ load bearing capacity by 400% to 600%

Line Bundles and Curves on a del Pezzo Order

Orders on surfaces provide a rich source of examples of noncommutative surfaces. Other than some existence results, very little is known about the various moduli spaces that can be associated to them. Even fewer examples have been explicitly computed. In this paper we compute the Picard and Hilbert schemes of an order on the projective plane ramified on a union of two conics. Our main result is that, upon carefully selecting the right Chern classes, the Hilbert scheme is a ruled surface over a genus two curve. Furthermore, this genus two curve is, in itself, the Picard scheme of the order

Discrete spherical means of directional derivatives and Veronese maps

We describe and study geometric properties of discrete circular and spherical means of directional derivatives of functions, as well as discrete approximations of higher order differential operators. For an arbitrary dimension we present a general construction for obtaining discrete spherical means of directional derivatives. The construction is based on using the Minkowski's existence theorem and Veronese maps. Approximating the directional derivatives by appropriate finite differences allows one to obtain finite difference operators with good rotation invariance properties. In particular, we use discrete circular and spherical means to derive discrete approximations of various linear and nonlinear first- and second-order differential operators, including discrete Laplacians. A practical potential of our approach is demonstrated by considering applications to nonlinear filtering of digital images and surface curvature estimation

Relativistic Hydrodynamics for Heavy--Ion Collisions -- II. Compression of Nuclear Matter and the Phase Transition to the Quark--Gluon Plasma

We investigate the compression of nuclear matter in relativistic hydrodynamics. Nuclear matter is described by a $\sigma-\omega$--type model for the hadron matter phase and by the MIT bag model for the quark--gluon plasma, with a first order phase transition between both phases. In the presence of phase transitions, hydrodynamical solutions change qualitatively, for instance, one-dimensional stationary compression is no longer accomplished by a single shock but via a sequence of shock and compressional simple waves. We construct the analytical solution to the ``slab-on-slab'' collision problem over a range of incident velocities. The performance of numerical algorithms to solve relativistic hydrodynamics is then investigated for this particular test case. Consequences for the early compressional stage in heavy--ion collisions are pointed out.Comment: 22 pages, 12 uuencoded figure

Hypertension management in patients with diabetes. The need for more aggressive therapy

WSTĘP. W dużych badaniach klinicznych wykazano już potrzebę ścisłej kontroli ciśnienia tętniczego u chorych na cukrzycę. Jednak niewiele wiadomo o tym, jak w praktyce klinicznej realizowane są zasady leczenia nadciśnienia tętniczego współistniejącego z cukrzycą. W celu zbadania tego problemu postawiono pytania: 1) czy chorzy na cukrzycę osiągają niższe wartości ciśnienia tętniczego niż osoby bez współistniejącej cukrzycy; 2) czy istnieją różnice między intensywnością leczenia chorych na cukrzycę i chorych bez niej oraz 3) czy leczenie cukrzycy wpływa na podjęcie decyzji o bardziej intensywnym leczeniu nadciśnienia tętniczego. MATERIAŁ I METODY. W celu uzyskania szczegółów dotyczących postępowania w nadciśnieniu tętniczym zgromadzono dokumentację medyczną z 2-letniego okresu leczenia 800 mężczyzn, kombatantów, leczonych z powodu nadciśnienia tętniczego. Porównano intensywność leczenia i kontrolę ciśnienia tętniczego u chorych na cukrzycę i u osób bez niej. Intensywność leczenia oceniono na podstawie wcześniej stosowanej formuły opisującej prawdopodobieństwo wzrostu liczby stosowanych leków hipotensyjnych. Oceniano również, czy zwiększenie dawek leków przeciwnadciśnieniowych było mniej prawdopodobne w czasie wizyt, na których zmieniano leczenie hipoglikemizujące. WYNIKI. Z 247 chorych na nadciśnienie tętnicze i cukrzycę u 73% ciśnienie tętnicze przekraczało 140/90 mm Hg, w porównaniu z 66% osób z 526-osobowej grupy bez cukrzycy (p = 0,04). U osób chorych na cukrzycę stosowano również znamiennie (p = 0,05) mniej intensywne leczenie hipotensyjne niż u pacjentów bez tego schorzenia. Postępowania tego nie można tłumaczyć poświęceniem większej uwagi klinicystów leczeniu cukrzycy. WNIOSKI. Istnieje potrzeba szybkiej poprawy skuteczności leczenia i lepszej kontroli ciśnienia wśród chorych na cukrzycę z współistniejącym nadciśnieniem tętniczym. Konieczne są dodatkowe dane w celu zrozumienia mało agresywnej postawy klinicystów w leczeniu nadciśnienia tętniczego współistniejącego z cukrzycą.INTRODUCTION. Clinical trials have demonstrated the importance of tight blood pressure control among patients with diabetes. However, little is known regarding the management of hypertension in patients with coexisting diabetes. To examine this issue, we addressed 1) whether hypertensive patients with coexisting diabetes are achieving lower levels of blood pressure than patients without diabetes, 2) whether there are differences in the intensity of antihypertensive medication therapy provided to patients with and without diabetes, and 3) whether diabetes management affects decisions to increase antihypertensive medication therapy. MATERIAL AND METHODS. We abstracted medical records to collect detailed information on 2 years of care provided for 800 male veterans with hypertension. We compared patients with and without diabetes on intensity of therapy and blood pressure control. Intensity of therapy was described using a previously validated measure that captures the likelihood of an increase in antihypertensive medications. We also determined whether increases in antihypertensive medications were less likely at those visits in which the diabetes medications were being adjusted. RESULTS. Of the 274 hypertensive patients with diabetes, 73% had a blood pressure 140/90 mm Hg, compared with 66% in the 526 patients without diabetes (P = 0.04). Diabetic patients also received significantly (P = 0.05) less intensive antihypertensive medication therapy than patients without diabetes. Less intensive therapy in diabetic patients could not be explained by clinicians being distracted by the treatment for diabetes. CONCLUSIONS. There is an urgent need to improve hypertension care and blood pressure control in patients with diabetes. Additional information is required to understand why clinicians are not more aggressive in managing blood pressure when patients also have diabetes

Retinal and choroidal thickness in early age-related macular degeneration

Purpose: To compare retinal thickness and choroidal thickness at increasing retinal eccentricity in individuals with early age-related macular degeneration (AMD) and in healthy controls using enhanced choroidal penetration, 3-dimensional optical coherence tomography at 1060 nm. Design: Cross-sectional study. Methods: Individuals with early AMD (n = 16; mean age, 71.6 ± 8.5 years) and a comparison group of healthy controls (n = 16; 67.6 ± 5.4 years) were recruited. Three-dimensional (20 degrees × 20 degrees) long-wavelength optical coherence tomography (1060 nm) images (approximately 8-μm axial resolution; 47 000 A scans/second, centered on the fovea) were obtained from all participants after pupil dilation. Retinal thickness was measured between the inner limiting membrane and the retinal pigment epithelium. Choroidal thickness was measured between the retinal pigment epithelium and the choroid–scleral interface. Thickness measurements were obtained subfoveally and at 0.5-mm intervals to a maximum of 2.0 mm nasally, temporally, superiorly, and inferiorly. The main outcome measures were retinal and choroidal thickness (measured in micrometers) at different eccentricities on vertical and horizontal meridians. Results: Mean retinal thickness was reduced significantly in the group of participants with early AMD compared with the control group at multiple locations within 2.0 mm of the fovea. This difference was most significant at the fovea, where the mean retinal thickness of the early AMD group was 179 ± 27 μm and that of the control group was 202 ± 18 μm (P = .008). There was no significant difference in choroidal thickness between groups at any location. Conclusions: Retinal thickness is reduced in early AMD, but choroidal thickness seems to be unaffected by the early disease process

Four-dimensional String Compactifications with D-Branes, Orientifolds and Fluxes

This review article provides a pedagogical introduction into various classes of chiral string compactifications to four dimensions with D-branes and fluxes. The main concern is to provide all necessary technical tools to explicitly construct four-dimensional orientifold vacua, with the final aim to come as close as possible to the supersymmetric Standard Model. Furthermore, we outline the available methods to derive the resulting four-dimensional effective action. Finally, we summarize recent attempts to address the string vacuum problem via the statistical approach to D-brane models.Comment: 331 pages, 7 figures, review prepared for Physics Reports, please send constructive comments to: [email protected], v2: refs added, v3: final version to appear in Phys. Rep