Medicinal plants in Mexico: healers' consensus and cultural importance

Medicinal plants are an important element of indigenous medical systems in Mexico. These resources are usually regarded as part of a culture's traditional knowledge. This study examines the use of medicinal plants in four indigenous groups of Mexican Indians, Maya, Nahua, Zapotec and - for comparative purposes - Mixe. With the first three the methodology was similar, making a direct comparison of the results possible. In these studies, the relative importance of a medicinal plant within a culture is documented using a quantitative method. For the analysis the uses were grouped into 9-10 categories of indigenous uses. This report compares these data and uses the concept of informant consensus originally developed by Trotter and Logan for analysis. This indicates how homogenous the ethnobotanical information is. Generally the factor is high for gastrointestinal illnesses and for culture bound syndromes. While the species used by the 3 indigenous groups vary, the data indicate that there exist well-defined criteria specific for each culture which lead to the selection of a plant as a medicine. A large number of species are used for gastrointestinal illnesses by two or more of the indigenous groups. At least in this case, the multiple transfer of species and their uses within Mexico seems to be an important reason for the widespread use of a species. Medicinal plants in other categories (e.g. skin diseases) are usually known only in one culture and seem to be part of its traditional knowledge.     

Minimizing thermal resistance and collector-to-substratecapacitance in SiGe BiCMOS on SOI

We describe a low fabrication cost, high-performance implementation of SiGe BiCMOS on SOL The use of high-energy implant allows the simultaneous formation of the subcollector and an additional n-type region below the buried oxide. The combination of buried oxide layer and floating n-type region underneath results in a very low collector-to-substrate capacitance. We also show that this process option achieves a much lower thermal resistance than using SOI with deep trench isolation, both reducing cost and curbing self-heating effects     

Physiological effects of 2.8 GHz radio-frequency radiation: a comparison of pulsed and continuous-wave radiation

Ketamine-anesthetized female Sprague-Dawley rats were exposed individually to far-field 2.8 GHz continuous wave (CW) and pulsed (2 microseconds, 500 pps) radio-frequency radiation (RFR) at average power densities of 30, 45, and 60 mW/cm2 [specific absorption rates (SAR) of 8.4, 12.6, and 16.8 W/kg, respectively] and to pulsed RFR at 75 mW/cm2 (SAR = 21 W/kg). Intermittent exposures were conducted to repeatedly increase colonic temperature from 38.5 to 39.5 degrees C. Colonic, tympanic, and subcutaneous temperatures, electrocardiogram, respiratory rate, and arterial blood pressure were continuously monitored and recorded. The time required to effect a 1 degree C colonic temperature increase varied inversely with the average power density used during exposure; however, the rate of cooling was independent of the heating rate. During pulsed irradiation, heart rate increased significantly at average power densities above 30 mW/cm2; heart rate increase during CW exposure was not significant. Heart rate returned to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. Pulsed RFR exposure caused a significantly greater increase in subcutaneous and tympanic temperatures than did CW exposure; however, no significant difference was noted between the effects of CW or pulsed RFR upon the rats' colonic temperature responses (heating and cooling time), heart rate, blood pressure, and respiratory rate.     

A comparison of optical-band based snow extent products during spring over North America

We compare the performances of two widely used hemispheric scale snow products during April, May, and June over North America. The Interactive Multisensor Snow and Ice Mapping System (IMS), based primarily on optical-band remotely sensed images, is the latest incarnation of a product that dates back to the 1960s and has been used as input to operational weather forecasting models as well as for establishing the historical climatology of snow extent over land surfaces. NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) has been used for numerous applications since it was launched aboard the Terra satellite platform in 1999. The MODIS snow product is based primarily on optical-band reflectances. We include in our analysis only observations that are largely unobstructed by clouds as determined using the MODIS cloud detection algorithm. Then, after removing the influences of terrain and projection errors, we identify regions and land surface types where discrepancies between these two products occur. We also compare IMS and MODIS to the snow reanalysis produced by the Canadian Meteorological Center (CMC).We find that on seasonal time scales, the most pronounced differences between the IMS and MODIS snow products occurs during the ablation season over North America. Our results corroborate earlier studies showing pronounced differences over the northern tundra in June, where MODIS appears to be in agreement with other observations; as well as differences in April and May in the boreal forest, where evidence suggests that both products may be biased (although MODIS biases may be smaller) in comparison with the CMC product (which is based on station observations). The influence of clouds may be a factor even though the analysis includes only clear days. Another possible explanation for these discrepancies involves the impact of numerous small lakes over the North American landscape on the interpretation of satellite retrievals in the visible band, although there are other potential sources of error in both products. For example, comparison to the CMC reanalysis suggests that MODIS may be overestimating snow during the ablation season in the boreal forest. The resolution of these discrepancies may affect our understanding of the seasonal snow cover cycle, the evaluation of and development of parameterization schemes for climate models, and the development of a climate data record for snow cover.     

Additive-Subtractive Two-Wavelength ESPI Contouring by Using a Synthetic Wavelength Phase Shift

The addition correlation of two speckle fields by simultaneousillumination at different wavelengths is used for object contouring ina Twyman-Green-type interferometer. Fringe visibility is enhancedwhen the stochastic speckle background intensity obtained from areference plane modulation is subtracted. We calculate the contourphase map by using a phase-shift algorithm in the syntheticwavelength. A comparison with a sequential illumination, phasedifference method based on a laser wavelength phase shift isgiven. The test setup does not need to be stable on aninterferometric scale, and therefore a method is provided that lendsitself to applications in noisy environments.     

1053-nm-wavelength selection in a diode-laser-pumped Nd:YLF laser

We report on a Nd:YLF laser that operates at 1053 nm without optical intracavity elements for the suppression of the stronger 1047-nm transition. The Nd:YLF crystal is end pumped by a fiber optically coupled 10-W diode-laser bar. The different thermal-lensing focal lengths of the two main lasing wavelengths in a plane-parallel resonator were used to achieve the selection by tilting the end mirror slightly from its optimum position for maximum output power. With 9.8-W cw diode-laser-pumping power the 1053-nm Nd:YLF laser produces a maximum output power of 1.9 W in cw operation and nearly 1 W of average power at a Q-switch repetition rate of 15 kHz. The highest slope efficiency of 47% achieved in cw operation.     

Design, fabrication, and characterization of diffraction gratings for neutron phase contrast imaging

We have developed a neutron phase contrast imaging method based on a grating interferometer setup. The principal constituents are two absorption gratings made of gadolinium and a phase modulating grating made of silicon. The design parameters of the setup, such as periodicity, structure heights of the gratings, and the distances between the gratings, are calculated. The fabrication of each grating is described in detail. The produced diffraction gratings were finally characterized within the setup, by locally evaluating the produced contrast (visibility) in each detector pixel, resulting in a visibility map over the whole grating size. An averaged value of 23% is achieved.     

Degeneracy and networked buffering: principles for supporting emergent evolvability in agile manufacturing systems

This article introduces new principles for improving upon the design and implementation of agile manufacturing and assembly systems. It focuses particularly on challenges that arise when dealing with novel conditions and the associated requirements of system evolvability, e.g. seamless reconfigurability to cope with changing production orders, robustness to failures and disturbances, and modifiable user-centric interfaces. Because novelty in manufacturing or the marketplace is only predictable to a limited degree, the flexible mechanisms that will permit a system to adequately respond to novelty cannot be entirely pre-specified. As a solution to this challenge, we propose how evolvability can become a pervasive property of the assembly system that, while constrained by the system??s historical development and domain-specific requirements, can emerge and re-emerge without foresight or planning. We first describe an important mechanism by which biological systems can cope with uncertainty through properties described as degeneracy and networked buffering. We discuss what degeneracy means, how it supports a system facing unexpected challenges, and we review evidence from simulations using evolutionary algorithms that support some of our conjectures in models with similarities to several assembly system contexts. Finally, we discuss potential design strategies for encouraging emergent changeability in assembly systems. We also discuss practical challenges to the realization of these concepts within a systems engineering context, especially issues related to system transparency, design costs, and efficiency. We discuss how some of these difficulties can be overcome while also elaborating on those factors that are likely to limit the applicability of these principles.