1,496 research outputs found
Phacoemulsification Cataract Surgery without Viscoelastic Substance: Bianchi’s Method
Life expectancy of the population increase and cataract development will affect all the people with aging. Cataract surgery, a worldwide performed procedure, evolves and progresses. However, different techniques exist, which could be selected for different cases. Any ideal technique should be safe, simple, fast, and easy to learn with good clinical outcome. This chapter will describe one technique to operate cataracts with those characteristics and to perform phacoemulsification cataract surgery without viscoelastic substance. Some advantages of this technique are related to avoiding viscoelastic potential problems, as postoperative intraocular pressure elevation or anterior chamber inflammation associated with viscoelastic. Moreover, a fundamental factor to remark is the difference between work into the anterior chamber with negative pressure or positive pressure. Because the anterior chamber is maintained by the balanced salt solution with the continuous irrigation without viscoelastic. Performing the capsulorhexis is easier. Other advantages are shorten surgical time, fewer economical cost, and potentially fewer complications. Some limitations are as follows: intraocular lens must be one piece foldable, and principally, patients with corneal endothelial pathology must be excluded. Tips, step-by-step surgery, recommendations, and evolution of the technique will be described, with the wish that many surgeons will try to perform Bianchi’s method (bimanual, microincision phacoemulsification cataract surgery without viscoelastic substance) for your next patient
Double collinear splitting amplitudes at next-to-leading order
We compute the next-to-leading order (NLO) QCD corrections to the 1 -> 2 splitting amplitudes in different dimensional regularization (DREG) schemes. Besides recovering previously known results, we explore new DREG schemes and analyze their consistency by comparing the divergent structure with the expected behavior predicted by Catani's formula. Through the introduction of scalar-gluons, we show the relation among splittings matrices computed using different schemes. Also, we extended this analysis to cover the double collinear limit of scattering amplitudes in the context of QCD+QED
Hadron plus photon production in polarized hadronic collisions at next-to-leading order accuracy
We compute the next-to-leading order QCD corrections to the polarized (and
unpolarized) cross sections for the production of a hadron accompanied by an
opposite-side prompt photon. This process, being studied at RHIC, permits us to
reconstruct partonic kinematics using experimentally measurable variables. We
study the correlation between the reconstructed momentum fractions and the true
partonic ones, which in the polarized case might allow us to reveal the
spin-dependent gluon distribution with a higher precision.Comment: 18 figures included. New version, discussion about polarized
asymmetries extended, 7 new figures, new reference
Transporte de arena en medanos litorales activos y colgados del sudeste de Buenos Aires
El transporte de arena por el viento es la principal fuente de suministro de sedimentos para la existencia de médanos litorales en playas arenosas, asà como un importante componente en los cálculos de balance sedimentario entre la playa (la fuente) y el médano (el destino). Para evaluar esto, se analizaron médanos del sudeste de la Provincia de Buenos Aires mediante un novedoso método de muestreo, que permite percibir diferencias en la dinámica y textura de la arena que conforman el perfil de velocidad, diferencias debido a su génesis y caracterÃsticas. El objetivo del trabajo fue analizar si habÃa diferencias apreciables cuantificables en las caracterÃsticas de médanos costeros colgados en acantilados de Mar del Plata y en médanos frontales, de costas abiertas al sur de la misma zona, en el arroyo de La Ballenera. Se observó que las arenas de médanos frontales son más gruesas que las de los médanos colgados, debido a las zonas de aporte y emplazamiento topográfico. Los mayores volúmenes de arena transportados son por la cara de barlovento y cresta. El perfil del arroyo La Ballenera se halla más influenciado por el efecto marino que el médano colgado, donde predomina la acción eólica. Se observó que cuando la velocidad del viento se duplica, el volumen transportado es 5 veces mayor, lo mismo que el to . El coeficiente de arrastre fue prácticamente despreciable a 2,6 m. La metodologÃa empleada para entrampar el sedimento resultó ser aceptable como una fase inicial para el monitoreo de la dinámica de sectores costeros dominados por el vientoThe sand transport by wind is the main sediment source of supply of silts for the presence of coast dunes in sandy beaches, as well as an important component in the calculations of sedimentary balance among the beach (the source) and the dune (the destination). To evaluate this action, dunes of the southeast of Buenos Aires Province were analyzed by means of a new sampling method that allows to see differences in the dynamics and texture of the sand that conform the profile of speed, differences due to its genesis and characteristic. The objective of the work was to analyze if there were quantifiable appreciable differences in the characteristics of coastal dunes hung in cliffs of Mar del Plata and in front dunes, of open costs to the south of the same area, in the La Ballenera Creek. It was observed that the sands of frontal dunes are coarser than those of the hunging dunes, due to the contribution areas and topographical location. The biggest transported volumes of sand are for the windward face and crest. The profile of the La Ballenera Creek is more influenced by the marine effect that the hunging dune, where the eolic action prevails. It was observed that when the speed of the wind is duplicated, the ported volume was 5 larger more, the same thing that the to . The Drag Coefficient went practically worthless to 2,6 m. The methodology used to trap the silt turned out to be acceptable as an initial phase for the monitoring of the dynamics of coastal sectors dominated by the wind
PENGARUH PENGGUNAAN POLYSTYRENE DAN ABU SEKAM PADI TERHADAP KARAKTERISTIK CAMPURAN LASTON LAPIS AUS (AC-WC)
ABSTRAKJalan merupakan prasarana penunjang aktivitas manusia di segala bidang, sehingga diperlukan perkerasan aspal yang dapat memenuhi kebutuhan dan memiliki mutu serta kualitas yang baik. Perkerasan aspal yang baik ditentukan oleh mutu dan kualitas campuran aspal. Salah satu usaha yang dilakukan dalam meningkatkan mutu serta kualitas campuran aspal adalah dengan memodifikasi sifat fisis aspal menggunakan bahan tambah (additive). Pada penelitian ini bahan tambah yang digunakan adalah material limbah polystyrene sebagai bahan substitusi aspal serta penggunaan abu sekam padi sebagai filler sebesar 50% dari berat total filler pada campuran AC-WC. Penelitian ini bertujuan untuk mengetahui pengaruh substitusi polystyrene ke dalam aspal pen. 60/70 serta penggunaan kombinasi 50% abu sekam padi dan 50% semen portland sebagai filler terhadap karakteristik campuran lapis aspal beton AC-WC dengan metode Marshall. Langkah awal pengujian dimulai dengan melakukan pemeriksaan sifat-sifat fisis aspal dengan dan tanpa polystyrene dan agregat, selanjutnya dilakukan pembuatan benda uji dengan variasi kadar aspal untuk penentuan kadar aspal optimum (KAO). Setelah KAO didapat kemudian dilakukan pembuatan benda uji tanpa substitusi limbah polystyrene sebagai benda uji awal dan dengan substitusi variasi persentase limbah polystyrene sebesar 7%, 9%, 11% terhadap berat aspal. Hasil penelitian menunjukkan nilai KAO tanpa substitusi polystyrene berada pada 6,30%. Sedangkan kadar aspal untuk substitusi yang paling efektif dan memenuhi semua persyaratan diperoleh pada kadar aspal 6,80% dengan substitusi 11% polystyrene terhadap berat aspal. Semakin besar persentase polystyrene semakin tinggi nilai stabilitas dan MQ, nilai stabilitas tertinggi yaitu sebesar 2761,96 kg dan nilai MQ tertinggi sebesar 1105,76 kg/mm. Nilai densitydan VFA tidak terjadi perubahan yang besar untuk semua substitusi variasi persentase polystyrene. Nilai VIM dan VMA cenderung meningkatsedangkan nilai flow mengalami penurunan seiring dengan peningkatan persentase polystyrene. Nilai durabilitas campuran AC-WC dengan dan tanpa substitusi variasi persentase polystyrenetelah memenuhi persyaratan yaitu > 90%.Kata Kunci : Laston, Aspal pen 60/70, Polystyrene, Abu Sekam Padi, Semen Portlan
Plectranthias lamillai, a new Anthiine fish species (Perciformes, Serranidae) from the Juan Fernández Archipelago, Chile
Plectranthias lamillai new species, is described and illustrated as a new anthiine serranid fish from Alejandro Selkirk Island, the westernmost island of the Juan Fernández Archipelago, about 700 km west of Chile at 33°45´S, 80°51´W. The following combination of characters distinguishes it from all other serranids: dorsal fin rays X,16; principal caudal-fin rays 17 (8+9); pectoral-fin rays 16; gillrakers 28 (8+20); tubed lateral-line scales 40-41; 10 rows of scales on cheek; maxilla narrow and rounded; posterior margin of bony opercle with three spinous processes, the middle one largest; subopercle 2-6 small serrae; pseudobranch with 24 filaments; circumpeduncular scales 16; pelvic fin inserted beneath base of pectoral fin, the tip reaching a vertical through base of tenth dorsal-fin spine, falling short of the anus; a broad red bar from sixth dorsal-fin spine to base of fifth ray, extending to anus and above anal fin as a narrow band that widens on the peduncle and then bifurcates over the upper and lower margins of the caudal fin; rest of the caudal fin yellowish. Pectoral fins orange; pelvic and anal fins whitish.No disponibl
Study of the effects of complexity on the manufacturing sector
There are factors linked to the complexity of manufacturing systems that influence the development of processes and affect the indicators of a company. The objective of this work is to identify the effects and factors that generate complexity in an economic sector, additional management methods and indicators that allow a proposed solution. The methodological approach is based on the instrument developed by the University of Bayreuth, which allows the identification of effects, factors, methods and management indicators. The study is based on a sample of 71 small and medium enterprises from the city of Cartagena, Colombia. The results show the relevant factors of complexity according to their type and origin that intervene in the manufacturing sector, as well as the different methodologies and management indicators that allow managers to improve the performance of their companies and the secto
Surface-Gravity Inequalities and Generic Conditions for Strong Cosmic Censorship
Transforming Penrose's intuitive picture of a strong cosmic censorship
principle, that generically forbids the appearance of locally naked space-time
singularities, into a formal mathematical proof, remains at present, one of the
most outstanding unsolved mathematical problems from the theory of
gravitational collapse. Part of the difficulty lies in the fact that we do not
possess yet a clear-cut understanding of the hypothesis needed for the
establishment of some sort of strong cosmic censorship theorem. What we have is
a selected list of solutions, which at first sight seem to go against cosmic
censorship, but at the end they fail in some way. However, the space of
solutions of Einstein's field equations is vast. In this article, we plan to
increase one's intuition by establishing a link between certain inequalities
for Cauchy-horizon stability and a set of generic conditions, such as a
reasonable equation of state--which determines whether the space-time is
asymptotically flat or not, an energy condition, and an hypothesis over the
class of metrics on which Einstein's field equations ought to be solved to
ensure strong cosmic censorship inside black-holes. With these tools in hand we
examine the Cauchy-horizon stability of the theory created by Born and
Infeld--whose action principle has been used as a prototype in superstring
theory, and the singularity-free Bardeen's black-hole model.Comment: 6 pages, 2 figures(type eps), REVTeX
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