I. The effects of variations in certain parameters upon the efficiency of in vivo hemodialysis with a Kiil dialyzer. II. Interfacial structure of concurrent air-water flow in a two-inch diameter horizontal tube.

Part I

Regression analyses are performed on in vivo hemodialysis data for the transfer of creatinine, urea, uric acid and inorganic phosphate to determine the effects of variations in certain parameters on the efficiency of dialysis with a Kiil dialyzer. In calculating the mass transfer rates across the membrane, the effects of cell-plasma mass transfer kinetics are considered. The concept of the effective permeability coefficient for the red cell membrane is introduced to account for these effects. A discussion of the consequences of neglecting cell-plasma kinetics, as has been done to date in the literature, is presented.

A physical model for the Kiil dialyzer is presented in order to calculate the available membrane area for mass transfer, the linear blood and dialysate velocities, and other variables. The equations used to determine the independent variables of the regression analyses are presented. The potential dependent variables in the analyses are discussed.

Regression analyses were carried out considering overall mass-transfer coefficients, dialysances, relative dialysances, and relative permeabilities for each substance as the dependent variables. The independent variables were linear blood velocity, linear dialysate velocity, the pressure difference across the membrane, the elapsed time of dialysis, the blood hematocrit, and the arterial plasma concentrations of each substance transferred. The resulting correlations are tabulated, presented graphically, and discussed. The implications of these correlations are discussed from the viewpoint of a research investigator and from the viewpoint of patient treatment.

Recommendations for further experimental work are presented.

Part II

The interfacial structure of concurrent air-water flow in a two-inch diameter horizontal tube in the wavy flow regime has been measured using resistance wave gages. The median water depth, r.m.s. wave height, wave frequency, extrema frequency, and wave velocity have been measured as functions of air and water flow rates. Reynolds numbers, Froude numbers, Weber numbers, and bulk velocities for each phase may be calculated from these measurements. No theory for wave formation and propagation available in the literature was sufficient to describe these results.

The water surface level distribution generally is not adequately represented as a stationary Gaussian process. Five types of deviation from the Gaussian process function were noted in this work. The presence of the tube walls and the relatively large interfacial shear stresses precludes the use of simple statistical analyses to describe the interfacial structure. A detailed study of the behavior of individual fluid elements near the interface may be necessary to describe adequately wavy two-phase flow in systems similar to the one used in this work.

The isotopic composition of energetic particles emitted from a large solar flare

We report measurements of isotope abundance ratios for 5-50 MeV/nuc nuclei from a large solar flare that occurred on September 23, 1978. The measurements were made by the Heavy Isotope Spectrometer Telescope (HIST) on the ISEE-3 satellite orbiting the Sun near an Earth-Sun libration point approximately one million miles sunward of the Earth. We report finite values for the isotope abundance ratios ¹³C/¹²C, ¹⁵N/¹⁴N, ¹⁸O/¹⁶O, ²²Ne/ ²⁰Ne, ²⁵Mg/²⁴Mg, and ²⁶Mg/²⁴Mg, and upper limits for the isotope abundance ratios ³He/⁴He, ¹⁴C/¹²C, ¹⁷O/¹⁶O, and ²¹Ne/²⁰Ne.

We measured element abundances and spectra to compare the September 23, 1978 flare with other flares reported in the literature. The flare is a typical large flare with "low" Fe/O abundance (≤ 0.1).

For ¹³C/¹²C, ¹⁵N/¹⁴N, ¹⁸O/¹⁶O, ²⁵Mg/ ²⁴Mg, and ²⁶Mg/²⁴Mg, our measured isotope abundance ratios agree with the solar system abundance ratios of Cameron (1981). For neon we measure ²²Ne/²⁰Ne = 0.109 + 0.026 - 0.019, a value that is different with confidence 97.5% from the abundance measured in the solar wind by Geiss at al. (1972) of ²²Ne/²⁰Ne = 0.073 ± 0.001. Our measurement for ²²Ne/²⁰Ne agrees with the isotopic composition of the meteoritic component neon-A.

Separate arguments appear to rule out simple mass fractionation in the solar wind and in our solar energetic particle measurements as the cause of the discrepancy in the comparison of the apparent compositions of these two sources of solar material.

A emergência da competência oral como sistema dinâmico, adaptativo e complexo no ensino-aprendizagem de inglês como língua adicional para iniciantes

No âmbito do ensino-aprendizagem de línguas adicionais, pesquisas acerca do desenvolvimento da oralidade têm demonstrado que se trata de um fenômeno multidimensional. Nakatani (2010) mostrou que o domínio de estratégias comunicacionais são indicadores de desempenho linguístico e se relacionam com a proficiência do aprendiz; Kang, Rubin e Pickering (2010) observaram que os traços fonológicos afetam a percepção sobre inteligibilidade e proficiência; Hewitt e Stephenson (2011), e Ahmadian (2012) indicaram que as condições psicológicas individuais interferem na qualidade da produção oral. Escribano (2004) sugeriu que a referência contextual é essencial na construção de sentido; Gao (2011) apontou os benefícios do ensino baseado na construção do sentido, a partir de metáforas conceptuais (LAKOFF e JOHNSON, 1980), codificação dupla (CLARK e PAIVIO, 1991) e esquemas imagéticos (LAKOFF, 1987); e Ellis e Ferreira-Junior (2009) demonstraram que as construções exibem efeitos de recência e priming, afetando o uso da linguagem dos parceiros interacionais. Tais estudos apontam para a natureza complexa da aquisição de L2, mas o fazem dentro do paradigma experimental da psicolinguística. Já Larsen-Freeman (2006), demonstra que a fluência, a precisão e a complexidade desenvolvem-se com o tempo, com alto grau de variabilidade, dentro do paradigma da Teoria da Complexidade. Em viés semelhante, Paiva (2011) observa que os sistemas de Aquisição de Segunda Língua (ASL) são auto-organizáveis. Esses trabalhos, no entanto, não abordaram aprendizes de L2 com proficiência inicial, como pretendo fazer aqui. Tendo como referenciais teóricos a Teoria da Complexidade e a Linguística Cognitiva, o presente trabalho apresenta um estudo de caso, qualitativo-interpretativista, com nuances quantitativos, que discute os processos de adaptação que emergiram na expressão oral de um grupo de aprendizes iniciantes de inglês como língua adicional no contexto vocacional. Parte do entendimento de que na sala de aula vários (sub)sistemas complexos coocorrem, covariando e coadaptando-se em diferentes níveis. A investigação contou com dados transcritos de três avaliações coletados ao longo de 28 horas de aula, no domínio ENTREVISTA DE EMPREGO. Após observar a produção oral das aprendizes, criei uma taxonomia para categorizar as adaptações que ocorreram na sintaxe, semântica, fonologia e pragmática da língua-alvo. Posteriormente organizei as categorias em níveis de prototipicidade (ROSCH et al, 1976) de acordo com as adaptações mais frequentes. Finalmente, avaliei a inteligibilidade de cada elocução, classificando-as em três níveis. A partir desses dados, descrevi como a prática oral dessas participantes emergiu e se desenvolveu ao longo das 28 horas. Os achados comprovam uma das premissas da Linguística Cognitiva ao mostrarem que os níveis de descrição linguística funcionam conjuntamente em prol do sucesso comunicacional. Além disso, demonstram que a função do professor, como discutem LARSEN-FREEMAN e CAMERON (2008), não é gerar uniformidade, mas sim oportunizar vivências que estabeleçam continuidade entre o mundo, o corpo e a mente

Implications of using On-Farm Flood Flow Capture to recharge groundwater and mitigate flood risks along the Kings River, CA

Two large hydrologic issues face the Kings Basin, severe and chronic overdraft of about 0.16M ac-ft annually, and flood risks along the Kings River and the downstream San Joaquin River. Since 1983, these floods have caused over $1B in damage in today’s dollars. Capturing flood flows of sufficient volume could help address these two pressing issues which are relevant to many regions of the Central Valley and will only be exacerbated with climate change. However, the Kings River has high variability associated with flow magnitudes which suggests that standard engineering approaches and acquisition of sufficient acreage through purchase and easements to capture and recharge flood waters would not be cost effective. An alternative approach investigated in this study, termed On-Farm Flood Flow Capture, involved leveraging large areas of private farmland to capture flood flows for both direct and in lieu recharge. This study investigated the technical and logistical feasibility of best management practices (BMPs) associated with On-Farm Flood Flow Capture. The investigation was conducted near Helm, CA, about 20 miles west of Fresno, CA. The experimental design identified a coordinated plan to determine infiltration rates for different soil series and different crops; develop a water budget for water applied throughout the program and estimate direct and in lieu recharge; provide a preliminary assessment of potential water quality impacts; assess logistical issues associated with implementation; and provide an economic summary of the program. At check locations, we measured average infiltration rates of 4.2 in/d for all fields and noted that infiltration rates decreased asymptotically over time to about 2 – 2.5 in/d. Rates did not differ significantly between the different crops and soils tested, but were found to be about an order of magnitude higher in one field. At a 2.5 in/d infiltration rate, 100 acres are required to infiltrate 10 CFS of captured flood flows. Water quality of applied flood flows from the Kings River had concentrations of COC (constituents of concern; i.e. nitrate, electrical conductivity or EC, phosphate, ammonium, total dissolved solids or TDS) one order of magnitude or more lower than for pumped groundwater at Terranova Ranch and similarly for a broader survey of regional groundwater. Applied flood flows flushed the root zone and upper vadose zone of nitrate and salts, leading to much lower EC and nitrate concentrations to a depth of 8 feet when compared to fields in which more limited flood flows were applied or for which drip irrigation with groundwater was the sole water source. In demonstrating this technology on the farm, approximately 3,100 ac-ft was diverted, primarily from April through mid-July, with about 70% towards in lieu and 30% towards direct recharge. Substantial flood flow volumes were applied to alfalfa, wine grapes and pistachio fields. A subset of those fields, primarily wine grapes and pistachios, were used primarily to demonstrate direct recharge. For those fields about 50 – 75% of water applied was calculated going to direct recharge. Data from the check studies suggests more flood flows could have been applied and infiltrated, effectively driving up the amount of water towards direct recharge. Costs to capture flood flows for in lieu and direct recharge for this project were low compared to recharge costs for other nearby systems and in comparison to irrigating with groundwater. Moreover, the potentially high flood capture capacity of this project suggests significant flood avoidance costs savings to downstream communities along the Kings and San Joaquin Rivers. Our analyses for Terranova Ranch suggest that allocating 25% or more flood flow water towards in lieu recharge and the rest toward direct recharge will result in an economically sustainable recharge approach paid through savings from reduced groundwater pumping. Two important issues need further consideration. First, these practices are likely to leach legacy salts and nitrates from the unsaturated zone into groundwater. We develop a conceptual model of EC movement through the unsaturated zone and estimated through mass balance calculations that approximately 10 kilograms per square meter of salts will be flushed into the groundwater through displacing 12 cubic meters per square meter of unsaturated zone pore water. This flux would increase groundwater salinity but an equivalent amount of water added subsequently is predicted as needed to return to current groundwater salinity levels. All subsequent flood flow capture and recharge is expected to further decrease groundwater salinity levels. Second, the project identified important farm-scale logistical issues including irrigator training; developing cropping plans to integrate farming and recharge activities; upgrading conveyance; and quantifying results. Regional logistical issues also exist related to conveyance, integration with agricultural management, economics, required acreage and Operation and Maintenance (O&M).

On-Farm Flood Flow Capture – addressing flood risks and groundwater overdraft in the Kings Basin, with potential applications throughout the Central Valley

Project fact sheet prepared in cooperation with the USDA Natural Resources Conservation Service and the Kings River Conservation District.

Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005

Background: The rising temperature of the world’s oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. Methodology/Principal Findings: Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers’ field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. Conclusions/Significance: Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch’s Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate