A Triple-Mode Feed-Forward Sigma-Delta Modulator Design For Gsm / Wcdma / Wlan Applications

This paper presents a cascaded 2-2-2 reconfigurable sigma-delta modulator that can handle GSM, WCDMA and WLAN standards. The modulator makes use of a low-distortion swing suppression topology which is highly suitable for wide band applications. In GSM mode, only the first stage (2nd order Σ-Δ ADC) is turned on to achieve 88dB dynamic range with oversampling ratio of 160 for a bandwidth of 200KHz; in WCDMA mode a 2-2 cascaded structure (4th order) is turned on with 1-bit in the first stage and 2-bit in the second stage to achieve 74 dB dynamic range with oversampling ratio of 16 for a bandwidth of 2MHz and a 2-2-2 cascaded MASH architecture with a 4-bit in the last stage to achieve a dynamic range of 58dB for a bandwidth of 20MHz. The novelty lies in the fact that unused blocks of second and third stages can be switched off taking into considerations like power consumption. The modulator is designed in TSMC 0.18um CMOS technology and operates at 1.8 supply voltage.

La relación entre el crimen organizado transnacional en la triple frontera y la politica exterior de seguridad de Brasil, Argentina y Paraguay entre 1996 y 2006

Esta monografía analiza la influencia del Crimen Organizado Transnacional en la Triple Frontera compartida por Argentina, Brasil y Paraguay y sus decisiones en Política Exterior durante 1996 y 2006. Se explica cómo el Crimen Organizado Transnacional y sus efectos en la gobernabilidad de los Estados pueden ser un motivo para el análisis de la situación como un Complejo de Seguridad Regional. A partir de la conceptualización de Seguridad Regional de Barry Buzan y Ole Waever y de Robert Stewart y Derrick Frazier, se avanza hacia el resultado de la investigación que permite exponer los factores que conllevaron a el surgimiento de un Complejo de Seguridad Regional entre Argentina, Brasil y Paraguay para diezmar los efectos del Crimen Organizado Transnacional en la Triple Frontera.

Las Escuelas P??as de Arag??n en el siglo XVIII

Analizar la realidad hist??rico-docente de las escuelas p??as de Arag??n en el siglo XIII. Conocer un periodo poco estudiado en general en Espa??a, el siglo XIII y m??s en su aspecto docente. Estudiar el desarrollo de una orden religiosa cuyo nacimiento no es aragon??s pero s?? su m??ximo esplendor, con gran proyecci??n social. Analizar la incidencia de una instituci??n de esta ??ndole en la vida de la comunidad. El m??todo de trabajo ha sido presentar documentos y extraer noticias de ellos, documentos procedentes no s??lo de los archivos escolapios sino tambi??n del Archivo Provincial para no tener una informaci??n parcial. Obras generales impresas y manuscritas, documentos, libros de car??cter interno, art??culos, memorias, folletos, revistas, etc.. Los hechos han sido analizados desde una perspectiva rigurosamente hist??rica. El aspecto pedag??gico se ha abordado desde la consideraci??n de la ense??anza en los colegios: metodolog??a, textos, formaci??n cristiana y moral, disciplinas, maestros ilustres, etc.. La situaci??n de la educaci??n en el siglo XVIII era deplorable siendo la fundaci??n de las escuelas p??as una soluci??n a la ineludible necesidad de educaci??n. Su car??cter gratuito y democr??tico evitaban todo g??nero de exclusivismos. Una de sus grandes conquistas fue la ruptura de la divisi??n entre ricos y pobres solucionando un problema social capacitando a los alumnos para que consiguiesen por s?? mismos su elevaci??n econ??mica y social dot??ndoles al tiempo de bienes morales y espirituales. Piedad y letras era su lema. Ayuntamiento y rentas de alg??n legado contribu??an al sostenimiento. La orden dotaba a sus maestros de una preparaci??n especializada y la ense??anza constitu??a un est??mulo de su vocaci??n ya que se dedicaban a la ense??anza por un cuarto voto. Su inter??s se centraba en formar hombres instruidos y educados como cristianos y como ciudadanos. Estos educadores se caracterizaron por estar abiertos a toda exigencia: por una parte conservaban el humanismo, y por otra cultivaban lo t??cnico y cient??fico testimoniando al mismo tiempo lo sacerdotal. Buscaron constantemente mejorar sus m??todos y orientaci??n pedag??gica. Llegaron a formar un grupo escolar completo: las escuelas graduadas. A pesar de todas las ventajas ofrecidas tuvieron que luchar contra un triple frente: la incomprensi??n de los privilegiados y estamentos superiores hacia la labor social de las escuelas, contradicci??n y falta de confianza del regalismo incipiente, y competencia con los intereses del magisterio existente, etc. Frente a estos aspectos negativos el pueblo sencillo al que favorec??a y promocionaba les acogi?? de manera entusiasta. Sus contribuciones al desarrollo pedag??gico: planificaci??n escolar, programas pr??cticos, metodolog??a diferenciada para ciencias y letras, selecci??n de textos, ense??anza en lenguas vivas, ense??anza del lat??n mediante la lengua materna, cooperaci??n con la familia, cantinas escolares, catequesis, formaci??n cultural y religiosa del pueblo, etc., ofrecen una dimensi??n clara de lo que supuso para Arag??n su fundaci??n y desarrollo.

Cómo enseñar la notación lingüística y matemática? : un triple enfoque: epistémico, interdisciplinar y sociocultural.

Resumen basado en el de la publicación

Ensenyar ci??ncies en angl??s : la superaci?? d'un triple repte

Resumen basado en el de la publicaci??n

Formation of triple helical nanofibers using self-assembling chiral benzene-1,3,5-tricarboxamides and reversal of the nanostructure's handedness using mirror image building blocks

Intertwining triple helical nanofibers with an overall handedness have been formed from self-assembling chiral benzene-1,3,5-tricarboxamides 1, 2 and 3, whereas the achiralbenzene-1,3,5-tricarboxamide 4 upon self-association gives rise to straight nanofibers without any twist and transmission electron microscopy images of chiral compounds clearly demonstrate that the handedness of the triple helical nanofibers can be reversed by using the enantiomeric benzene-1,3,5-tricarboxamide building blocks.

A comparison of the relative toxicity of bone meal and other P sources used as remedial treatments to the earthworm Eisenia fetida

It has been suggested that sources of P could be used to remediate metal-contaminated soil. The toxicity of four potential P sources, potassium hydrogen phosphate (PHP), triple superphosphate (TSP), rock phosphate (RP) and raw bone meal (RBM) to Eisenia fetida was determined. The concentration of P that is statistically likely to kill 50% of the population (LC50) for PHP, TSP and RBM was determined in OECD acute toxicity tests. 14 day LC50s expressed as bulk P concentration lay in the range 3319–4272 mg kg−1 for PHP, 3107–3590 mg kg−1 for TSP and 1782–2196 mg kg−1 for RBM (ranges present the 95% confidence intervals). For PHP and TSP mortality was significantly impacted by the electrical conductivity of the treated soils. No consistent relationship existed between mortality and electrical conductivity, soil pH and available (Olsen) P across the PHP, TSP and RBM amendment types. In RP toxicity tests mortality was low and it was not possible to determine a LC50 value. Incineration of bone meal at temperatures between 200 and 300 ◦C, pre-washing the bone meal, co-amendment with 5% green waste compost and delaying introduction of earthworms after bone meal amendments by 21 days or more led to significant reductions in the bone meal toxicity. These results are consistent with the toxicity being associated with the release and/or degradation of a soluble organic component present in raw bone meal. Bone meal can be used as an earthworm-friendly remedial amendment in metal-contaminated soils but initial additions may have a negative effect on any earthworms surviving in the contaminated soil before the organic component in the bone meal degrades in the soil.

Triple isotope (δD, δ17O, δ18O) study on precipitation, drip water and speleothem fluid inclusions for a central European cave (NW Switzerland)

Deuterium (dD) and oxygen (d18O) isotopes are powerful tracers of the hydrological cycle and have been extensively used for paleoclimate reconstructions as they can provide information on past precipitation, temperature and atmospheric circulation. More recently, the use of 17Oexcess derived from precise measurement of d17O and d18O gives new and additional insights in tracing the hydrological cycle whereas uncertainties surround this proxy. However, 17Oexcess could provide additional information on the atmospheric conditions at the moisture source as well as about fractionations associated with transport and site processes. In this paper we trace water stable isotopes (dD, d17O and d18O) along their path from precipitation to cave drip water and finally to speleothem fluid inclusions for Milandre cave in northwestern Switzerland. A two year-long daily resolved precipitation isotope record close to the cave site is compared to collected cave drip water (3 months average resolution) and fluid inclusions of modern and Holocene stalagmites. Amount weighted mean dD, d18O and d17O are �71.0‰, �9.9‰, �5.2‰ for precipitation, �60.3‰, �8.7‰, �4.6‰ for cave drip water and �61.3‰, �8.3‰, �4.7‰ for recent fluid inclusions respectively. Second order parameters have also been derived in precipitation and drip water and present similar values with 18 per meg for 17Oexcess whereas d-excess is 1.5‰ more negative in drip water. Furthermore, the atmospheric signal is shifted towards enriched values in the drip water and fluid inclusions (D of ~ þ 10‰ for dD). The isotopic composition of cave drip water exhibits a weak seasonal signal which is shifted by around 8e10 months (groundwater residence time) when compared to the precipitation. Moreover, we carried out the first d17O measurement in speleothem fluid inclusions, as well as the first comparison of the d17O behaviour from the meteoric water to the fluid inclusions entrapment in speleothems. This study on precipitation, drip water and fluid inclusions will be used as a speleothem proxy calibration for Milandre cave in order to reconstruct paleotemperatures and moisture source variations for Western Central Europe.

Potential sites of triple-helical nucleic acid formation in chromosomes of Rhynchosciara (Diptera: Sciaridae) and Drosophila melanogaster

Antibodies to specific nucleic acid conformations are amongst the methods that have allowed the study of non-canonical (Watson-Crick) DNA structures in higher organisms. In this work, the structural limitations for the immunological detection of DNA.RNA hybrid duplexes were examined using specific RNA homopolymers as probes for homopolymer polydeoxyadenylic acid (poly(dA)).polydeoxythymidylic acid (poly(dT))-rich regions of Rhynchosciara americana (Diptera: Sciaridae) chromosomes. Anti-DNA.RNA duplexes did not react with the complex formed between chromosomal poly(dA) and exogenous polyuridylic acid (poly(rU)). Additionally, poly(rU) prevented the detection of polyadenylic acid.poly(dT) hybrid duplexes preformed in situ. These results raised the possibility that three-stranded structures rather than duplexes were formed in chromosomal sites. To test this hypothesis, the specificity of antibodies to triple-helical nucleic acids was reassessed employing distinct nucleic acid configurations. These antibodies were raised to the poly(dA).poly(rU).poly(rU) complex and have been used here for the first time in immunocytochemistry. Anti-triplex antibodies recognised the complex poly(dA).poly(rU).poly(rU) assembled with poly(rU) in poly(dA).poly(dT)-rich homopolymer regions of R. americana chromosomes. The antibodies could not detect short triplex stretches, suggesting the existence of constraints for triple-helix detection, probably related to triplex tract length. In addition, anti-poly(dA).poly(rU).poly(rU) antibodies reacted with the pericentric heterochromatin of RNase-treated polytene chromosomes of R. americana and Drosophila melanogaster. In apparent agreement with data obtained in cell types from other organisms, the results of this work suggest that significant triple-helix DNA extensions can be formed in pericentric regions of these species.

Triple- and quadruple-escape peaks in HPGe detectors: Experimental observation and Monte Carlo simulation

The triple- and quadruple-escape peaks of 6.128 MeV photons from the (19)F(p,alpha gamma)(16)O nuclear reaction were observed in an HPGe detector. The experimental peak areas, measured in spectra projected with a restriction function that allows quantitative comparison of data from different multiplicities, are in reasonably good agreement with those predicted by Monte Carlo simulations done with the general-purpose radiation-transport code PENELOPE. The behaviour of the escape intensities was simulated for some gamma-ray energies and detector dimensions; the results obtained can be extended to other energies using an empirical function and statistical properties related to the phenomenon. (C) 2010 Elsevier B.V. All rights reserved.

Magnetoresistance oscillations in triple quantum wells under microwave irradiation

The interference of magneto-intersubband oscillations and microwave-induced resistance oscillations is studied in high-density triple quantum wells. We give an introduction into magnetotransport in trilayer systems and focus on photoresistance measurements. The power and frequency dependence of the observed magnetoresistance oscillations can be described by the inelastic mechanism of photoresistance, generalized to the three-subband case. (C) 2009 Elsevier B.V. All rights reserved.

Magneto-intersubband oscillations in triple quantum wells

We present magnetotransport studies of high-density triple quantum well samples with different barrier widths. Because of electron transitions between three occupied 2D subbands, the magneto-resistance shows magneto-intersubband oscillations whose periodicity is determined by the subband separation energies. Temperature-dependent measurements allow us to extract quantum lifetime of electrons. A theoretical consideration of the observed phenomenon is also presented. (C) 2009 Elsevier B.V. All rights reserved.