Faster techniques to evolve wavelet coefficients for better fingerprint image compression

In this article, techniques have been presented for faster evolution of wavelet lifting coefficients for fingerprint image compression (FIC). In addition to increasing the computational speed by 81.35%, the coefficients performed much better than the reported coefficients in literature. Generally, full-size images are used for evolving wavelet coefficients, which is time consuming. To overcome this, in this work, wavelets were evolved with resized, cropped, resized-average and cropped-average images. On comparing the peak- signal-to-noise-ratios (PSNR) offered by the evolved wavelets, it was found that the cropped images excelled the resized images and is in par with the results reported till date. Wavelet lifting coefficients evolved from an average of four 256 256 centre-cropped images took less than 1/5th the evolution time reported in literature. It produced an improvement of 1.009 dB in average PSNR. Improvement in average PSNR was observed for other compression ratios (CR) and degraded images as well. The proposed technique gave better PSNR for various bit rates, with set partitioning in hierarchical trees (SPIHT) coder. These coefficients performed well with other fingerprint databases as well.

Evolution of Better Wavelet Coefficients for Fingerprint Image Compression using cropped images

This paper explains the Genetic Algorithm (GA) evolution of optimized wavelet that surpass the cdf9/7 wavelet for fingerprint compression and reconstruction. Optimized wavelets have already been evolved in previous works in the literature, but they are highly computationally complex and time consuming. Therefore, in this work, a simple approach is made to reduce the computational complexity of the evolution algorithm. A training image set comprised of three 32x32 size cropped images performed much better than the reported coefficients in literature. An average improvement of 1.0059 dB in PSNR above the classical cdf9/7 wavelet over the 80 fingerprint images was achieved. In addition, the computational speed was increased by 90.18 %. The evolved coefficients for compression ratio (CR) 16:1 yielded better average PSNR for other CRs also. Improvement in average PSNR was experienced for degraded and noisy images as well

Die Privatisierung der Öffentlichen Personennahverkehrs (ÖPNV) und die damit verbundene Problematik des marktwirtschaftlichen und interventionistischen Dualismus am Beispiel des Schienenpersonennahverkehrs (SPNV) in der Fläche

Der SPNV als Bestandteil des ÖPNV bildet einen integralen Bestandteil der öffentlichen Daseinsvorsorge. Insbesondere Flächenregionen abseits urbaner Ballungszentren erhalten durch den SPNV sowohl ökonomisch als auch soziokulturell wichtige Impulse, so dass die Zukunftsfähigkeit dieser Verkehrsart durch geeignete Gestaltungsmaßnahmen zu sichern ist. ZIELE: Die Arbeit verfolgte das Ziel, derartige Gestaltungsmaßnahmen sowohl grundlagentheoretisch herzuleiten als auch in ihrer konkreten Ausformung für die verkehrswirtschaftliche Praxis zu beschreiben. Abgezielt wurde insofern auf strukturelle Konzepte als auch praktische Einzelmaßnahmen. Der Schwerpunkt der Analyse erstreckte sich dabei auf Deutschland, wobei jedoch auch verkehrsbezogene Privatisierungserfahrungen aus anderen europäischen Staaten und den USA berücksichtigt wurden. METHODEN: Ausgewertet wurden deutschsprachige als auch internationale Literatur primär verkehrswissenschaftlicher Ausrichtung sowie Fallbeispiele verkehrswirtschaftlicher Privatisierung. Darüber hinaus wurden Entscheidungsträger der Deutschen Bahn (DB) und DB-externe Eisenbahnexperten interviewt. Eine Gruppe 5 DB-interner und 5 DB-externer Probanden nahm zusätzlich an einer standardisierten Erhebung zur Einschätzung struktureller und spezifischer Gestaltungsmaßnahmen für den SPNV teil. ERGEBNISSE: In struktureller Hinsicht ist die Eigentums- und Verfügungsregelung für das gesamte deutsche Bahnwesen und den SPNV kritisch zu bewerten, da der dominante Eisenbahninfrastrukturbetreiber (EIU) in Form der DB Netz AG und die das Netz nutzenden Eisenbahnverkehrs-Unternehmen (EVUs, nach wie vor zumeist DB-Bahnen) innerhalb der DB-Holding konfundiert sind. Hieraus ergeben sich Diskriminierungspotenziale vor allem gegenüber DB-externen EVUs. Diese Situation entspricht keiner echten Netz-Betriebs-Trennung, die wettbewerbstheoretisch sinnvoll wäre und nachhaltige Konkurrenz verschiedener EVUs ermöglichen würde. Die seitens der DB zur Festigung bestehender Strukturen vertretene Argumentation, wonach Netz und Betrieb eine untrennbare Einheit (Synergie) bilden sollten, ist weder wettbewerbstheoretisch noch auf der Ebene technischer Aspekte akzeptabel. Vielmehr werden durch die gegenwärtige Verquickung der als Quasimonopol fungierenden Netzebene mit der Ebene der EVU-Leistungen Innovationspotenziale eingeschränkt. Abgesehen von der grundsätzlichen Notwendigkeit einer konsequenten Netz-Betriebs-Trennung und dezentraler Strukturen sind Ausschreibungen (faktisch öffentliches Verfahren) für den Betrieb der SPNV-Strecken als Handlungsansatz zu berücksichtigen. Wettbewerb kann auf diese Weise gleichsam an der Quelle einer EVU-Leistung ansetzen, wobei politische und administrative Widerstände gegen dieses Konzept derzeit noch unverkennbar sind. Hinsichtlich infrastruktureller Maßnahmen für den SPNV ist insbesondere das sog. "Betreibermodell" sinnvoll, bei dem sich das übernehmende EIU im Sinne seiner Kernkompetenzen auf den Betrieb konzentriert. Die Verantwortung für bauliche Maßnahmen sowie die Instandhaltung der Strecken liegt beim Betreiber, welcher derartige Leistungen am Markt einkaufen kann (Kostensenkungspotenzial). Bei Abgabeplanungen der DB Netz AG für eine Strecke ist mithin für die Auswahl eines Betreibers auf den genannten Ausschreibungsmodus zurückzugreifen. Als kostensenkende Einzelmaßnahmen zur Zukunftssicherung des SPNV werden abschließend insbesondere die Optimierung des Fahrzeugumlaufes sowie der Einsatz von Triebwagen anstatt lokbespannter Züge und die weiter forcierte Ausrichtung auf die kundenorientierte Attraktivitätssteigerung des SPNV empfohlen. SCHLUSSFOLGERUNGEN: Handlungsansätze für eine langfristige Sicherung des SPNV können nicht aus der Realisierung von Extrempositionen (staatlicher Interventionismus versus Liberalismus) resultieren, sondern nur aus einem pragmatischen Ausgleich zwischen beiden Polen. Dabei erscheint eine Verschiebung hin zum marktwirtschaftlichen Pol sinnvoll, um durch die Nutzung wettbewerbsbezogener Impulse Kostensenkungen und Effizienzsteigerungen für den SPNV herbeizuführen.

Patent DE10 2004 037 519 B4 “Sensor Process and Device for Determining a Physical Value“. A Proof of Concept

At present, a fraction of 0.1 - 0.2% of the patients undergoing surgery become aware during the process. The situation is referred to as anesthesia awareness and is obviously very traumatic for the person experiencing it. The reason for its occurrence is mostly an insufficient dosage of the narcotic Propofol combined with the incapability of the technology monitoring the depth of the patient’s anesthetic state to notice the patient becoming aware. A solution can be a highly sensitive and selective real time monitoring device for Propofol based on optical absorption spectroscopy. Its working principle has been postulated by Prof. Dr. habil. H. Hillmer and formulated in DE10 2004 037 519 B4, filed on Aug 30th, 2004. It consists of the exploitation of Intra Cavity Absorption effects in a two mode laser system. In this Dissertation, a two mode external cavity semiconductor laser, which has been developed previously to this work is enhanced and optimized to a functional sensor. Enhancements include the implementation of variable couplers into the system and the implementation of a collimator arrangement into which samples can be introduced. A sample holder and cells are developed and characterized with a focus on compatibility with the measurement approach. Further optimization concerns the overall performance of the system: scattering sources are reduced by re-splicing all fiber-to-fiber connections, parasitic cavities are eliminated by suppressing the Fresnel reflexes of all one fiber ends by means of optical isolators and wavelength stability of the system is improved by the implementation of thermal insulation to the Fiber Bragg Gratings (FBG). The final laser sensor is characterized in detail thermally and optically. Two separate modes are obtained at 1542.0 and 1542.5 nm, tunable in a range of 1nm each. Mode Full Width at Half Maximum (FWHM) is 0.06nm and Signal to Noise Ratio (SNR) is as high as 55 dB. Independent of tuning the two modes of the system can always be equalized in intensity, which is important as the delicacy of the intensity equilibrium is one of the main sensitivity enhancing effects formulated in DE10 2004 037 519 B4. For the proof of concept (POC) measurements the target substance Propofol is diluted in the solvents Acetone and DiChloroMethane (DCM), which have been investigated for compatibility with Propofol beforehand. Eight measurement series (two solvents, two cell lengths and two different mode spacings) are taken, which draw a uniform picture: mode intensity ratio responds linearly to an increase of Propofol in all cases. The slope of the linear response indicates the sensitivity of the system. The eight series are split up into two groups: measurements taken in long cells and measurements taken in short cells.

Development of directly modulated high speed telecommunication lasers based on surface defined feedback gratings

High-speed semiconductor lasers are an integral part in the implemen- tation of high-bit-rate optical communications systems. They are com- pact, rugged, reliable, long-lived, and relatively inexpensive sources of coherent light. Due to the very low attenuation window that exists in the silica based optical fiber at 1.55 μm and the zero dispersion point at 1.3 μm, they have become the mainstay of optical fiber com- munication systems. For the fabrication of lasers with gratings such as, distributed bragg reflector or distributed feedback lasers, etching is the most critical step. Etching defines the lateral dimmensions of the structure which determines the performance of optoelectronic devices. In this thesis studies and experiments were carried out about the exist- ing etching processes for InP and a novel dry etching process was de- veloped. The newly developed process was based on Cl2/CH4/H2/Ar chemistry and resulted in very smooth surfaces and vertical side walls. With this process the grating definition was significantly improved as compared to other technological developments in the respective field. A surface defined grating definition approach is used in this thesis work which does not require any re-growth steps and makes the whole fabrication process simpler and cost effective. Moreover, this grating fabrication process is fully compatible with nano-imprint lithography and can be used for high throughput low-cost manufacturing. With usual etching techniques reported before it is not possible to etch very deep because of aspect ratio dependent etching phenomenon where with increasing etch depth the etch rate slows down resulting in non-vertical side walls and footing effects. Although with our de- veloped process quite vertical side walls were achieved but footing was still a problem. To overcome the challenges related to grating defini- tion and deep etching, a completely new three step gas chopping dry etching process was developed. This was the very first time that a time multiplexed etching process for an InP based material system was demonstrated. The developed gas chopping process showed extra ordinary results including high mask selectivity of 15, moderate etch- ing rate, very vertical side walls and a record high aspect ratio of 41. Both the developed etching processes are completely compatible with nano imprint lithography and can be used for low-cost high-throughput fabrication. A large number of broad area laser, ridge waveguide laser, distributed feedback laser, distributed bragg reflector laser and coupled cavity in- jection grating lasers were fabricated using the developed one step etch- ing process. Very extensive characterization was done to optimize all the important design and fabrication parameters. The devices devel- oped have shown excellent performance with a very high side mode suppression ratio of more than 52 dB, an output power of 17 mW per facet, high efficiency of 0.15 W/A, stable operation over temperature and injected currents and a threshold current as low as 30 mA for almost 1 mm long device. A record high modulation bandwidth of 15 GHz with electron-photon resonance and open eye diagrams for 10 Gbps data transmission were also shown.

Optimization of Processing Technology for Commercial Drying of Bananas (Matooke)

Summary - Cooking banana is one of the most important crops in Uganda; it is a staple food and source of household income in rural areas. The most common cooking banana is locally called matooke, a Musa sp triploid acuminate genome group (AAA-EAHB). It is perishable and traded in fresh form leading to very high postharvest losses (22-45%). This is attributed to: non-uniform level of harvest maturity, poor handling, bulk transportation and lack of value addition/processing technologies, which are currently the main challenges for trade and export, and diversified utilization of matooke. Drying is one of the oldest technologies employed in processing of agricultural produce. A lot of research has been carried out on drying of fruits and vegetables, but little information is available on matooke. Drying of matooke and milling it to flour extends its shelf-life is an important means to overcome the above challenges. Raw matooke flour is a generic flour developed to improve shelf stability of the fruit and to find alternative uses. It is rich in starch (80 - 85%db) and subsequently has a high potential as a calorie resource base. It possesses good properties for both food and non-food industrial use. Some effort has been done to commercialize the processing of matooke but there is still limited information on its processing into flour. It was imperative to carry out an in-depth study to bridge the following gaps: lack of accurate information on the maturity window within which matooke for processing into flour can be harvested leading to non-uniform quality of matooke flour; there is no information on moisture sorption isotherm for matooke from which the minimum equilibrium moisture content in relation to temperature and relative humidity is obtainable, below which the dry matooke would be microbiologically shelf-stable; and lack of information on drying behavior of matooke and standardized processing parameters for matooke in relation to physicochemical properties of the flour. The main objective of the study was to establish the optimum harvest maturity window and optimize the processing parameters for obtaining standardized microbiologically shelf-stable matooke flour with good starch quality attributes. This research was designed to: i) establish the optimum maturity harvest window within which matooke can be harvested to produce a consistent quality of matooke flour, ii) establish the sorption isotherms for matooke, iii) establish the effect of process parameters on drying characteristics of matooke, iv) optimize the drying process parameters for matooke, v) validate the models of maturity and optimum process parameters and vi) standardize process parameters for commercial processing of matooke. Samples were obtained from a banana plantation at Presidential Initiative on Banana Industrial Development (PIBID), Technology Business Incubation Center (TBI) at Nyaruzunga – Bushenyi in Western Uganda. A completely randomized design (CRD) was employed in selecting the banana stools from which samples for the experiments were picked. The cultivar Mbwazirume which is soft cooking and commonly grown in Bushenyi was selected for the study. The static gravitation method recommended by COST 90 Project (Wolf et al., 1985), was used for determination of moisture sorption isotherms. A research dryer developed for this research. All experiments were carried out in laboratories at TBI. The physiological maturity of matooke cv. mbwazirume at Bushenyi is 21 weeks. The optimum harvest maturity window for commercial processing of matooke flour (Raw Tooke Flour - RTF) at Bushenyi is between 15-21 weeks. The finger weight model is recommended for farmers to estimate harvest maturity for matooke and the combined model of finger weight and pulp peel ratio is recommended for commercial processors. Matooke isotherms exhibited type II curve behavior which is characteristic of foodstuffs. The GAB model best described all the adsorption and desorption moisture isotherms. For commercial processing of matooke, in order to obtain a microbiologically shelf-stable dry product. It is recommended to dry it to moisture content below or equal to 10% (wb). The hysteresis phenomenon was exhibited by the moisture sorption isotherms for matooke. The isoteric heat of sorption for both adsorptions and desorption isotherms increased with decreased moisture content. The total isosteric heat of sorption for matooke: adsorption isotherm ranged from 4,586 – 2,386 kJ/kg and desorption isotherm from 18,194– 2,391 kJ/kg for equilibrium moisture content from 0.3 – 0.01 (db) respectively. The minimum energy required for drying matooke from 80 – 10% (wb) is 8,124 kJ/kg of water removed. Implying that the minimum energy required for drying of 1 kg of fresh matooke from 80 - 10% (wb) is 5,793 kJ. The drying of matooke takes place in three steps: the warm-up and the two falling rate periods. The drying rate constant for all processing parameters ranged from 5,793 kJ and effective diffusivity ranged from 1.5E-10 - 8.27E-10 m2/s. The activation energy (Ea) for matooke was 16.3kJ/mol (1,605 kJ/kg). Comparing the activation energy (Ea) with the net isosteric heat of sorption for desorption isotherm (qst) (1,297.62) at 0.1 (kg water/kg dry matter), indicated that Ea was higher than qst suggesting that moisture molecules travel in liquid form in matooke slices. The total color difference (ΔE*) between the fresh and dry samples, was lowest for effect of thickness of 7 mm, followed by air velocity of 6 m/s, and then drying air temperature at 70˚C. The drying system controlled by set surface product temperature, reduced the drying time by 50% compared to that of a drying system controlled by set air drying temperature. The processing parameters did not have a significant effect on physicochemical and quality attributes, suggesting that any drying air temperature can be used in the initial stages of drying as long as the product temperature does not exceed gelatinization temperature of matooke (72˚C). The optimum processing parameters for single-layer drying of matooke are: thickness = 3 mm, air temperatures 70˚C, dew point temperature 18˚C and air velocity 6 m/s overflow mode. From practical point of view it is recommended that for commercial processing of matooke, to employ multi-layer drying of loading capacity equal or less than 7 kg/m², thickness 3 mm, air temperatures 70˚C, dew point temperature 18˚C and air velocity 6 m/s overflow mode.

1.55 µm High-Speed QDs Lasers for Optical Telecommunication Applications

In this work investigation of the QDs formation and the fabrication of QD based semiconductor lasers for telecom applications are presented. InAs QDs grown on AlGaInAs lattice matched to InP substrates are used to fabricate lasers operating at 1.55 µm, which is the central wavelength for far distance data transmission. This wavelength is used due to its minimum attenuation in standard glass fibers. The incorporation of QDs in this material system is more complicated in comparison to InAs QDs in the GaAs system. Due to smaller lattice mismatch the formation of circular QDs, elongated QDs and quantum wires is possible. The influence of the different growth conditions, such as the growth temperature, beam equivalent pressure, amount of deposited material on the formation of the QDs is investigated. It was already demonstrated that the formation process of QDs can be changed by the arsenic species. The formation of more round shaped QDs was observed during the growth of QDs with As2, while for As4 dash-like QDs. In this work only As2 was used for the QD growth. Different growth parameters were investigated to optimize the optical properties, like photoluminescence linewidth, and to implement those QD ensembles into laser structures as active medium. By the implementation of those QDs into laser structures a full width at half maximum (FWHM) of 30 meV was achieved. Another part of the research includes the investigation of the influence of the layer design of lasers on its lasing properties. QD lasers were demonstrated with a modal gain of more than 10 cm-1 per QD layer. Another achievement is the large signal modulation with a maximum data rate of 15 Gbit/s. The implementation of optimized QDs in the laser structure allows to increase the modal gain up to 12 cm-1 per QD layer. A reduction of the waveguide layer thickness leads to a shorter transport time of the carriers into the active region and as a result a data rate up to 22 Gbit/s was achieved, which is so far the highest digital modulation rate obtained with any 1.55 µm QD laser. The implementation of etch stop layers into the laser structure provide the possibility to fabricate feedback gratings with well defined geometries for the realization of DFB lasers. These DFB lasers were fabricated by using a combination of dry and wet etching. Single mode operation at 1.55 µm with a high side mode suppression ratio of 50 dB was achieved.

Visuelle Transaktionen: Kontrolle der Nebenläufigkeit bei synchroner Gruppenarbeit

Vortragsfolien eines im Mai 1999 auf einem Datenbankseminar (intern) gehaltenen Vortrags. Zusammenfassung: Der Vortrag fasst anschaulich einige der Themen zusammen, an denen das FG Datenbanken/Interaktive Systeme um das Jahr 2000 (und einige Jahre davor und danach) gearbeitet hat: Navigieren und Editieren von NF2-Tabellen mit dem DB-Editor ESCHER, das Fingerkonzept, Focus/Nimbus-Fragen, erweiterte Transaktionskonzepte für datenbankgestützte synchrone Gruppenarbeit. Die im Ausblick aufgestellte These, wonach visuelle Transaktionen ein attraktives Forschungsthema bleiben, dürfte auch heute noch gelten, zumal die Herausforderungen mobiler Geräte und neuer Interaktionsformen in den letzten Jahren hinzugekommen sind.

Aplicació del càlcul d’esforços en 2n ordre en estructures metàl·liques segons el CTE i NBE-EA-95

Aquest estudi se centra en el document del CTE que es refereix a les estructures metàl·liques d’acer, concretament en els càlculs a tenir en compte a l’hora de realitzar pòrtics d’estructura d’edificació amb perfils metàl·lics laminats. Aquest document és el DB-SE-A, que són les sigles de “Document Bàsic Seguretat Estructural Acer”. Aquest document introdueix algunes modificacions en el mètode de càlcul de les estructures metàl·liques respecte l’antiga norma. La idea d’aquest estudi és fer una comparació entre les dues normes – la vella i ja derogada, i la nova i vigent – i com tracten el càlcul d’esforços en segon ordre i el tractament de les imperfeccions. Com ja s’ha comentat aquest Document Bàsic de la Seguretat Estructural en Acer del CTE (DB-SE-A) substitueix l’antiga norma que es referia al càlcul d’estructura metàl·lica, la NBE-EA-95. En l’aplicació de les accions i el càlcul d’esforços s’utilitza del CTE el Document Bàsic dedicat a les accions en l’edificació (DB-SE-AE) i que substitueix l’antiga NBE-AE-88

Arqueología micropolítica del discurso bibliotecario. La biblioteca escolar ecológica productora de nueva subjetividad : su efecto en las redes sociales y bases de datos documentales.

El análisis micropolítico de los Discursos Bibliotecarios (DB) desinviste a las maquinas codificadoras de las misiones, que la institución bibliotecaria reproduce como valor agregado ligado a un modo de ser con base territorial; desmonta las máquinas axiomáticas de los manifiestos bibliotecarios que producen un valor agregado incluyendo forzadamente como deudores de conocimiento a los que no dominan el saber acumulado; y revela el valor agregado del capitalismo mundial integrado (CMI) que instaura procedimientos tácticos cada vez mas autoreferenciales (normas, pautas y directrices). En oposición a esos dispositivos de alineación, culpabilización, responsabilización y control, proponemos un proceso de singularización bibliotecaria en función de la producción de información ambiental en una Biblioteca Escolar Ecológica en conexión con redes sociales y bases de datos documentales.

Plan de Mercadeo: Caso SCAD Colombia Ltda.

SCAD Colombia es una empresa que provee soluciones para la automatización documental a nivel latinoamericano, actualmente distribuye una solución desarrollada por la empresa Readsoft de Suecia llamada Process Director, la solución hoy en día no tiene los niveles de reconocimiento ni de ventas esperados, sin embargo, tiene un mercado interesante e inexplorado en su mayoría. Para el año 2012 SCAD Colombia pretende buscar la manera que le permita obtener los objetivos establecidos para dicha solución en el mercado. El presente documento “Plan de mercadeo: Caso SCAD Colombia” propone una serie de análisis y estrategias que la empresa puede seguir con el fin de conseguir los resultados esperados.

Análisis del proceso que condujo a la construcción del concepto de explotación inserto en el Protocolo para prevenir, reprimir y sancionar la trata de personas, incorporado a la legislación colombiana a través de la Ley 800 de 2003

El objetivo de este trabajo de grado es describir una disputa política por el significado del concepto de explotación en el marco de la redacción del “Protocolo para prevenir, reprimir y sancionar la trata de personas, especialmente mujeres y niños”, en el cual se define aquello que se entiende por trata de personas. La construcción de este concepto excluye e invisibiliza otros tipos de explotación comunes en el sistema de producción capitalista contemporánea que pertenecen al universo de violencia objetiva sistémica a través del énfasis en la explotación sexual que hace parte de la violencia subjetiva.

Complicaciones del uso del angioseal vs compresión manual en cateterismo cardíaco mediante punción femoral

Objetivo: Comparar las complicaciones del uso de Angioseal® versus compresión manual en los pacientes llevados a cateterismo cardíaco en el Servicio de Hemodinamia de la Fundación Santa Fe de Bogotá, del 1º de enero de 2005 al 31 de diciembre de 2010, mediante punción arterial femoral percutánea. Metodología: Se realizó un Estudio Observacional, Analítico, de tipo Cohorte Retrospectiva. Partiendo de dos grupos de personas con indicación de cateterismo cardíaco por cualquier causa, uno expuesto al procedimiento con Angioseal® y el otro con compresión manual. Resultados: Con el uso de Angioseal® versus compresión manual la aparición de complicaciones fue 7,3% vs 4,1%, estas diferencias no fueron significativas (OR 1,81 IC95 0,96-3,40; RR 1,75 IC95 0,96-3,18) . La enfermedad coronaria (OR 2,27 IC95 1,07-4,79; RR 2,18 IC95 1,06-4,46) y a la colocación de stent (OR 3,49 IC95 1,82-6,69; RR 3,25 IC95 1,75-6,02 si se relacionaron significativamente con la aparición de complicaciones menores. Conclusión: No encontramos soporte para aprobar o desaprobar el uso de Angioseal® o compresión manual como manejo de la hemostasia, con respecto a las complicaciones. Sin embargo, se encontró que la colocación de stents está fuertemente relacionada con el desarrollo de complicaciones menores, lo cual hace que estos pacientes deban ser objeto de monitorización estrecha.

Alteración de la atención y concentración en estudiantes de medicina que realizan turnos de noche

El sueño, es indispensable para la recuperación, física, mental y de procesos como la consolidación de memoria, atención y lenguaje. La privación de sueño (PS) incide en la atención y concentración. La PS es inherente a la formación médica, pero no es claro el papel de los turnos nocturnos en estudiantes, porque no cumplen con un objetivo académico, pero hay relación con disminución de la salud, productividad, accidentes, y alteraciones en diversas actividades. Está descrito el impacto de la PS sobre la capacidad de aprendizaje y aspectos como el ánimo y las relaciones interpersonales. MÉTODOS: Se realizó un estudio analítico observacional de cohorte longitudinal, con tres etapas de medición a 180 estudiantes de Medicina de la Universidad del Rosario, que evaluó atención selectiva y concentración mediante la aplicación de la prueba d2, validada internacionalmente para tal fin. RESULTADOS: Se estudiaron 180 estudiantes, 115 mujeres, 65 hombres, entre los 18 y 26 años (promedio 21). Al inicio del estudio dormían en promedio 7,9 horas, cifra que se redujo a 5,8 y 6,3 en la segunda y tercera etapa respectivamente. El promedio de horas de sueño nocturno, disminuyó en el segundo y tercer momento (p<0,001); Además se encontró mediante la aplicación de la prueba d2, que hubo correlación significativa directa débil, entre el promedio de horas de sueño, y el promedio del desempeño en la prueba (r=0.168, p=0.029) CONCLUSIONES: La PS, con períodos de sueño menores a 7,2 horas, impactan de manera importante la atención selectiva, la concentración

Efectividad del tratamiento farmacológico de la agresividad en pacientes con trastorno límite de la personalidad. Revisión sistemática

Introducción: el Trastorno Límite de la Personalidad afecta del 2% al 6% de los adultos en Estados Unidos. Es una condición de alta relevancia dentro de las patologías psiquiátricas debido a características como impulsividad, inestabilidad en las relaciones interpersonales, disregulación en el estado de ánimo y comportamiento agresivo. Esto determina un impacto negativo en la funcionalidad del individuo siendo la agresividad contra sí mismo o contra otras personas uno de sus componentes claves. Métodos: Revisión sistemática de la literatura de artículos de bases de datos y búsqueda manual de revistas relacionadas que aportaran la mejor evidencia con el fin de encontrar estudios que evaluaran, con instrumentos objetivos, los tratamientos farmacológicos disponibles para el manejo de la agresividad en el TLP .Se evaluó calidad metodológica y los estudios se organizaron en tablas de evidencia. Resultados: La búsqueda arrojo 1081 artículos de los cuales se seleccionaron 52 como potenciales y cinco fueron incluidos en esta revisión. Se clasificaron como nivel de evidencia Ib. El topiramato, el aripiprazol, el divalproato y la fluoxetina mostraron mejores resultados que el placebo especialmente en agresividad e impulsividad. El topiramato fue asociado con pérdida de peso. Los medicamentos fueron seguros y bien tolerados. Discusión: Los medicamentos evaluados mostraron ser mejores que placebo. La diversidad en las escalas utilizadas genera complejidad en la interpretación de resultados. Conclusión: La evidencia sugiere que el tratamiento farmacológico es efectivo en síntomas como agresividad e impulsividad comparado con placebo. Deben considerarse estudios que evalúen combinaciones de fármacos y psicoterapia.