Canvis ambientals i modelació antròpica del territori entre l'època ibèrica i l'alt medieval a Catalunya: aportacions de la palinologia

[spa] En los últimos años ha aumentado el interés arqueológico por los cambios territoriales de época histórica. Asimismo, el número de registros polínicos ha aumentado sensiblemente. A pesar de que la falta de marcos cronológicos fiables impone límites a las interpretaciones sobre antropización, el presente artículo pretende realizar una síntesis de los cambios paleoambientales documentados entre los siglos VIII aC y XII dC, haciendo especial referencia a las transformaciones humanas del entorno. Este conjunto de datos polínicos hace evidente una intervención humana al inicio del periodo ibérico, presión que se intensifica durante el iberismo Pleno con la expansión de actividades agrícolas. El mundo romano significa una explotación del espacio menos extensiva, si bien el el siglo VII dC se produce una extensión de los pastos tanto en sectores elevados del Pirineo como de litoral catalán que modifica profundamente el paisaje. [eng] The archaeological interest on the environmental changes during historical times has increased during the last decades. In accordance, a number of palynological from NE Spain records has been recently published. Despite chronological frame works are not yet enough reliable, this paper proposes a synthesis of landscape changes from VIIIth century BC to XIIth century AD. Palynological data suggest the presence of human impacts at ghe beginning of iberic times. Humans pressure, mainly farmning activities, intensified during iberian times. Roman times record a less extensive land use but at the IVth century AD, grazing expanded at regional scale. Pastures expanded again at VIIth century AD, reaching high altitudes in the Pyrenees while at littoral plains, meadows were used for grazing. This period resulted in a deep change of the Catalan lansacapes.

Estudio clínico comparativo de la eficacia de azitromicina frente a amoxicilina/Ac. Clavulánico en el tratamiento de infecciones orales.

Fundamentos: el objetivo de este estudio fue comparar la eficacia. seguridad y tolerancia de la azitromicina frente a amoxicilina/ac. clavulánico en el tratamiento de pacientes con infecciones bucales agudas de origen odontogénico. Pacientes y Método: en este estudio abierto, comparativo y multicéntrico, se incluyeron 208 pacientes con infección bucal aguda de origen odontogénico, asignados aleatoriamente a dos grupos; 102 pacientes recibieron azitromicina, y 106 pacientes recibieron amoxicilina/ac. clavulánico. Se realizaron una historia clínica y una exploración física, y se tomaron muestras de sangre y orina. En cada una de las visitas, se recogieron los signos y síntomas característicos de la infección. Resultados: el nivel de respuesta fue similar en ambos grupos terapéuticos, obteniéndose un porcentaje de curación o mejoría superior al 90%. Azitromicina fue mejor tolerada y tuvo mejor cumplimiento que amoxicilina/ac. clavulánico. Los efectos adversos fueron en su mayoría gastrointestinales. Conclusión: Azitromicina y amoxicilina/clavulánico fueron igualmente efectivos en el tratamiento de infecciones agudas de origen odontogénico.

Una nueva subespecie para Euphorbia flavicoma DC. (Euphorbiaceae)

Con motivo de los estudios biosistemáticos realizados en el marco de una tesis doctoral [J. SIMON, Estudis Biosistics en especies Euphorbia de la subsecció Galarrhaei en la mediterránea occidental, inédita, 1993] sobre las especies no nanofanerófitas y con cápsulas verrugosas de Euphorbia subsect. Galarrhaei (Boiss.) Pax, detectamos dentro del grupo de Euphorbia flavicoma DC. algunas poblaciones de difícil adscripción. El estudio de más de 700 pliegos de esta especie, así como el análisis multivariante, realizado sobre un total de 88 caracteres, nos obliga a proponer una nueva subespecie definida ante todo por el tipo de indumento de tallos y hojas, formado por tricomas largos y patentes -muy diferentes de los cortos y crespos que se presentan en el resto de las subespecies-, y que además recubre ambas caras foliares -en el resto de las subespecies los tricomas tan solo se encuentran en el margen foliar-. Como caracteres complementarios, se pueden destacar la disposición claramente refleja de las hojas y su aspecto ligeramente seríceo.

Produccion de frutos y semillas en Diplotaxis erucoides(L.) DC. sometida a diferentes tratamientos de polinizacion

En este trabajo se estudia el sistema reproductivo de Diplotaxis erucoides (L.) DC. (Brassicaceae), una especie arvense ampliamente distribuida en los cultivos y los márgenes de caminos de la región mediterránea. Mediante polinizaciones manuales con polen procedente de la propia flor (autogamia), de flores del mismo individuo (geitonogamia) y de flores de individuos de otras poblaciones (alogamia) se analiza el efecto de los diferentes tratamientos de polinización sobre la producción de frutos y semillas. Los resultados obtenidos muestran que Diplotaxis erucoides es una especie con capacidad para autopolinizarse. Hay diferencias significativas en la fertilidad y en el número de semillas por fruto entre los tratamientos que generan alogamia y los que originan autogamia. Dentro de los tratamientos con autogamia, la fertilidad disminuye progresivamente en el paso de geitonogamia a autogamia por autopolinización inducida y a autogamia por autopolinización espontánea.

Bidirectional relationship between the Body Mass Index and Substance Use in Young Men

BACKGROUND: Obesity and substance use are major concern in young people. This study explored the bidirectional longitudinal relationships between the body mass index (BMI) of young men and their use of: 1) four classes of non-medical prescription drugs; 2) alcohol; 3) tobacco; and 4) cannabis. METHODS: Baseline and follow-up data from the Cohort Study on Substance Use Risk Factors were used (n=5,007). A cross-lagged panel model, complemented by probit models as sensitivity analysis, was run to determine the bidirectional relationships between BMI and substance use. Alcohol was assessed using risky single-occasion drinking (RSOD); tobacco, using daily smoking; and cannabis, using hazardous cannabis use (defined as twice-weekly or more cannabis use). Non-medical prescription drugs use (NMPDU) included opioid analgesics, sedatives/sleeping pills, anxiolytics and stimulants. RESULTS: Different associations were found between BMI and substance use. Only RSOD (β= -.053, p=.005) and NMPDU of anxiolytics (β=.040, p=.020) at baseline significantly predicted BMI at follow-up. Baseline RSOD predicted a lower BMI at follow-up while baseline NMPDU of anxiolytics predicted higher BMI at follow-up. Furthermore, BMI at baseline significantly predicted daily smoking (β=.050, p=.007) and hazardous cannabis use (β=.058, p=.030). CONCLUSIONS: Our results suggest different associations between BMI and the use of various substances by young men. However, only RSOD and NMPDU of anxiolytics predicted BMI, whereas BMI predicted daily smoking and hazardous cannabis use.

Medidas de resistividade elétrica DC em sólidos: como efetuálas corretamente

This paper deals with the most common methods for determining the dc electrical resistivity in solid materials. A brief overview of the fundamental concepts related to the electrical resistivity on materials is introduced. Undoubtedly, the most common and useful procedure to determine the electrical resistivity (rho) is the fourpoint probe method. Some crucial mistakes regarding the experimental procedure and the appropriated correction factors are found in the literature. Thus, the correction factor for the most common sample geometries were gathered and revised in order to provide an easy way to use and apply them.

Magnetic properties of ZnGeP2:Mn

In this work magnetic properties of ZnGeP2:Mn were investigated in DC magnetic field with SQUID magnetometer in the temperature range from 3 K up to 400 K and in AC magnetic field with AC magnetometer in the temperature range from 77 K up to 350 K in frequency range from 500 Hz up to 18 KHz. Three ZnGeP2:Mn samples were studied with Mn concentration c = 1.5 % mass, 3 % mass and 3.5 % mass.

Estudo químico e perfil cromatográfico das cascas de Aspidosperma parvifolium A. DC. ("pau-pereira")

Four known alkaloids, uleine, epiuleine, apparicine and desmethyluleine, besides the isoprenoids lupeol and stigmasterol were isolated from the stem bark of Aspidosperma parvifolium. Their identification was based on spectroscopic analysis (UV, IR, ¹H-NMR, 13C-NMR, MS). The chromatographic profile of the ethanolic extract was obtained by HPLC and uleine, epiuleine and apparicine were identified in the extract.

Converter Supply Transformer For LVDC Distribution System

This master’s thesis is focused on optimizing the parameters of a distribution transformer with respect to low voltage direct current (LVDC) distribution system. One of the main parts of low voltage direct current (LVDC) distribution system is transformer. It is studied from several viewpoints like filtering capabilities of harmonics caused by rectifier, losses and short circuit current limiting Determining available short circuit currents is one of the most important aspects of designing power distribution systems. Short circuits and their effects must be considered in selecting electrical equipment, circuit protection and other devices.

Position sensorless electrically excited synchronous motor drive for industrial use based on direct flux linkage and torque control

Synchronous machines with an AC converter are used mainly in large drives, for example in ship propulsion drives as well as in rolling mill drives in steel industry. These motors are used because of their high efficiency, high overload capacity and good performance in the field weakening area. Present day drives for electrically excited synchronous motors are equipped with position sensors. Most drives for electrically excited synchronous motors will be equipped with position sensors also in future. This kind of drives with good dynamics are mainly used in metal industry. Drives without a position sensor can be used e.g. in ship propulsion and in large pump and blower drives. Nowadays, these drives are equipped with a position sensor, too. The tendency is to avoid a position sensor if possible, since a sensor reduces the reliability of the drive and increases costs (latter is not very significant for large drives). A new control technique for a synchronous motor drive is a combination of the Direct Flux Linkage Control (DFLC) based on a voltage model and a supervising method (e.g. current model). This combination is called Direct Torque Control method (DTC). In the case of the position sensorless drive, the DTC can be implemented by using other supervising methods that keep the stator flux linkage origin centered. In this thesis, a method for the observation of the drift of the real stator flux linkage in the DTC drive is introduced. It is also shown how this method can be used as a supervising method that keeps the stator flux linkage origin centered in the case of the DTC. In the position sensorless case, a synchronous motor can be started up with the DTC control, when a method for the determination of the initial rotor position presented in this thesis is used. The load characteristics of such a drive are not very good at low rotational speeds. Furthermore, continuous operation at a zero speed and at a low rotational speed is not possible, which is partly due to the problems related to the flux linkage estimate. For operation in a low speed area, a stator current control method based on the DFLC modulator (DMCQ is presented. With the DMCC, it is possible to start up and operate a synchronous motor at a zero speed and at low rotational speeds in general. The DMCC is necessary in situations where high torque (e.g. nominal torque) is required at the starting moment, or if the motor runs several seconds at a zero speed or at a low speed range (up to 2 Hz). The behaviour of the described methods is shown with test results. The test results are presented for the direct flux linkage and torque controlled test drive system with a 14.5 kVA, four pole salient pole synchronous motor with a damper winding and electric excitation. The static accuracy of the drive is verified by measuring the torque in a static load operation, and the dynamics of the drive is proven in load transient tests. The performance of the drive concept presented in this work is sufficient e.g. for ship propulsion and for large pump drives. Furthermore, the developed methods are almost independent of the machine parameters.

Hybrid LC Filter for Power Electronic Drives: Theory and Implementation

Power electronic converter drives use, for the sake of high efficiency, pulse-width modulation that results in sequences of high-voltage high-frequency steep-edged pulses. Such a signal contains a set of high harmonics not required for control purposes. Harmonics cause reflections in the cable between the motor and the inverter leading to faster winding insulation ageing. Bearing failures and problems with electromagnetic compatibility may also result. Electrical du/dt filters provide an effective solution to problems caused by pulse-width modulation, thereby increasing the performance and service life of the electrical machines. It is shown that RLC filters effectively decrease the reflection phenomena in the cable. Improved (simple, but effective) solutions are found for both differential- and common-mode signals; these solutions use a galvanic connection between the RLC filter star point and the converter DC link. Foil chokes and film capacitors are among the most widely used components in high-power applications. In actual applications they can be placed in different parts of the cabinet. This fact complicates the arrangement of the cabinet and decreases the reliability of the system. In addition, the inductances of connection wires may prevent filtration at high frequencies. This thesis introduces a new hybrid LC filter that uses a natural capacitance between the turns of the foil choke based on integration of an auxiliary layer into it. The main idea of the hybrid LC filter results from the fact that both the foil choke and the film capacitors have the same roll structure. Moreover, the capacitance between the turns (“intra capacitance”) of the foil inductors is the reason for the deterioration of their properties at high frequencies. It is shown that the proposed filter has a natural cancellation of the intra capacitance. A hybrid LC filter may contain two or more foil layers isolated from each other and coiled on a core. The core material can be iron or even air as in the filter considered in this work. One of the foils, called the main foil, can be placed between the inverter and the motor cable. Other ones, called auxiliary foils, may be connected in star to create differential-mode noise paths, and then coupled to the DC link midpoint to guarantee a traveling path, especially for the common-mode currents. This way, there is a remarkable capacitance between the main foil and the auxiliary foil. Investigations showed that such a system can be described by a simple equivalent LC filter in a wide range of frequencies. Because of its simple hybrid construction, the proposed LC filter can be a cost-effective and competitive solution for modern power drives. In the thesis, the application field of the proposed filter is considered and determined. The basics of hybrid LC filter design are developed further. High-frequency behaviour of the proposed filter is analysed by simulations. Finally, the thesis presents experimental data proving that the hybrid LC filter can be used for du/dt of PWM pulses and reduction of common-mode currents.

De usu symbolorum circa geometrica theoremata ac problemata demonstranda

Invocatio: D.D.

Volatile compounds from Rosmarinus officinalis L. and Baccharis dracunculifolia DC. Growing in southeast coast of Brazil

Chemical composition of leaf volatiles of Rosmarinus officinalis and Baccharis dracunculifolia cultured in Southeast of Brazil has been characterized by GC/MS after simultaneous distillation-extraction. The main components in volatiles of these species showed in common α-pinene, myrcene, 1,8 cineole and camphor. Camphor was the major component among volatiles of B. dracunculifolia and R. officinalis with concentrations exceeding 25%. B. dracunculifolia volatiles possessed more sesquiterpenes (21.4%) than R. officinalis (16.7%), such as caryophyllene (1.9%) and α-humulene (0.4%). Lower concentrations of nerolidol and spathulenol were achieved in volatiles of B. dracunculifolia. Considering both species, there was a predominance of monoterpenes.