Ion exchange determines iodine-131 concentration in aqueous samples

Inorganic radioiodide in aqueous media is analyzed by separating the radioactive iodine-131 as the iodide ion on a silver chloride column. The activity in the final precipitate may be determined by beta or gamma counting

Direct determination of lead-210 by liquid-scintillation counting

Soft betas, the internal conversion electrons, and unconverted gamma rays from lead-210 are efficiently detected in a liquid scintillation counting system with efficiency of 97 percent. The counter is interfaced with a multichannel pulse height analyzer. The spectra obtained is stored on paper tape and plotted on an x-y plotter

Antitrust and the Future of Nursing: Federal Competition Policy and the Scope of Practice

TesisEn los últimos tiempos existe una tendencia mundial hacia un mayor consumo de frutas y hortalizas, motivado fundamentalmente por una creciente preocupación por una dieta más equilibrada, con menor proporción de carbohidratos, grasas y con una mayor cantidad de fibra dietética, vitaminas y minerales. Los vegetales han tenido generalmente una forma tradicional de consumo que se ha ido modificando con el surgimiento de nuevas tecnologías de procesamiento y de preservación, (Lay Ma, 1993). El yacón (Smallanthus sonchifolia) es una raíz que se domesticó en los Andes desde la época preincaica. Los centros de mayor diversidad se localizan en las zonas fronterizas de Perú con Bolivia y Ecuador. Sin embargo, su hábitat natural se extiende desde el sur de Colombia hasta el norte de Argentina (Ferro, 2006). En el caso de frutas el objetivo es entregar al mercado un producto de la mejor calidad, con el fin de ofrecer al consumidor mejor presentación, sabor, nutrientes, aceptación y que el consumidor pague por lo que se ofrece, con el fin de obtener los beneficios deseados. Los vegetales frescos deben conservarse adecuadamente hasta el momento del consumo. Las condiciones y duración del almacenamiento influyen mucho en el aspecto y valor nutritivo. Los productos vegetales al ser cosechados deben ser acondicionados a temperaturas bajas a fin de alargar su vida útil. Con el fin de evitar que durante el almacenamiento a bajas temperaturas se produzca una alteración de los alimentos se realiza una operación denominada escaldado cuyo fin principal es el de la inactivación de las enzimas responsables de la degradación. A este respecto se utiliza la peroxidasa como indicador ya que es la más termo resistente. La finalidad básica del escaldado es la inactivación enzimática, pero además se producen otros efectos deseables en el alimento: Limpieza, se quita el polvo, los gases superficiales y aparece una nueva tonalidad en el alimento; eliminación de la carga microbiana superficial; eliminación de los gases que se encuentran ocluidos en los tejidos; suavizado del material (Loannou, 2013). En el presente trabajo se estudió el efecto que tiene la temperatura de almacenamiento y el escaldado del yacón (Smallanthus sonchifolia) sobre la peroxidasa y la variación de vitamina C, con esto se realizó el estudio de estabilidad, a fin de demostrar que un producto, podría conservarse durante largos periodos de almacenamiento y así poder retener componentes nutritivos

Bounded Model Checking of State-Space Digital Systems: The Impact of Finite Word-Length Effects on the Implementation of Fixed-Point Digital Controllers Based on State-Space Modeling

The extensive use of digital controllers demands a growing effort to prevent design errors that appear due to finite-word length (FWL) effects. However, there is still a gap, regarding verification tools and methodologies to check implementation aspects of control systems. Thus, the present paper describes an approach, which employs bounded model checking (BMC) techniques, to verify fixed-point digital controllers represented by state-space equations. The experimental results demonstrate the sensitivity of such systems to FWL effects and the effectiveness of the proposed approach to detect them. To the best of my knowledge, this is the first contribution tackling formal verification through BMC of fixed-point state-space digital controllers.Comment: International Symposium on the Foundations of Software Engineering 201

The Importance of Optical Wavelength Data on Atmospheric Retrievals of Exoplanet Transmission Spectra

Exoplanet transmission spectra provide rich information about the chemical composition, clouds and temperature structure of exoplanet atmospheres. Most exoplanet transmission spectra only span infrared wavelengths ($\gtrsim$ 1 $\rm{\mu m}$), which can preclude crucial atmospheric information from shorter wavelengths. Here, we explore how retrieved atmospheric parameters from exoplanet transmission spectra change with the addition of optical data. From a sample of 14 giant planets with transit spectra from 0.3-4.5 $\rm{\mu m}$, primarily from the Hubble and Spitzer space telescopes, we apply a free chemistry retrieval to planetary spectra for wavelength ranges of 0.3-4.5 $\rm{\mu m}$, 0.6-4.5 $\rm{\mu m}$, and 1.1-4.5 $\rm{\mu m}$. We analyse the posterior distributions of these retrievals and perform an information content analysis, finding wavelengths below 0.6 $\rm{\mu m}$ are necessary to constrain cloud scattering slope parameters ($\log{a}$ and $\gamma$) and alkali species Na and K. There is limited improvement in the constraints on the remaining atmospheric parameters. Across the population, we find limb temperatures are retrieved colder than planetary equilibrium temperatures but have an overall good agreement with Global Circulation Models. As JWST extends to a minimum wavelength of 0.6 $\rm{\mu m}$, we demonstrate that exploration into complementing JWST observations with optical HST data is important to further our understanding of aerosol properties and alkali abundances in exoplanet atmospheres.Comment: 26 pages, 12 figures. Accepted for publication in the Astronomical Journa

Interventions for Indigenous Peoples making health decisions: a systematic review

Background: Shared decision-making facilitates collaboration between patients and health care providers for informed health decisions. Our review identified interventions to support Indigenous Peoples making health decisions. The objectives were to synthesize evidence and identify factors that impact the use of shared decision making interventions. Methods: An Inuit and non-Inuit team of service providers and academic researchers used an integrated knowledge translation approach with framework synthesis to coproduce a systematic review. We developed a conceptual framework to organize and describe the shared decision making processes and guide identification of studies that describe interventions to support Indigenous Peoples making health decisions. We conducted a comprehensive search of electronic databases from September 2012 to March 2022, with a grey literature search. Two independent team members screened and quality appraised included studies for strengths and relevance of studies’ contributions to shared decision making and Indigenous self-determination. Findings were analyzed descriptively in relation to the conceptual framework and reported using guidelines to ensure transparency and completeness in reporting and for equity-oriented systematic reviews. Results: Of 5068 citations screened, nine studies reported in ten publications were eligible for inclusion. We categorized the studies into clusters identified as: those inclusive of Indigenous knowledges and governance (“Indigenous-oriented”)(n = 6); and those based on Western academic knowledge and governance (“Western-oriented”)(n = 3). The studies were found to be of variable quality for contributions to shared decision making and self-determination, with Indigenous-oriented studies of higher quality overall than Western-oriented studies. Four themes are reflected in an updated conceptual framework: 1) where shared decision making takes place impacts decision making opportunities, 2) little is known about the characteristics of health care providers who engage in shared decision making processes, 3) community is a partner in shared decision making, 4) the shared decision making process involves trust-building. Conclusions: There are few studies that report on and evaluate shared decision making interventions with Indigenous Peoples. Overall, Indigenous-oriented studies sought to make health care systems more amenable to shared decision making for Indigenous Peoples, while Western-oriented studies distanced shared decision making from the health care settings. Further studies that are solutions-focused and support Indigenous self-determination are needed

Incidence of and outcomes after misaligned deployment of the Talent Thoracic Stent Graft System

ObjectiveVarious types of device-specific adverse events can occur during deployment of thoracic stent grafts due to the high flow rate and severe aortic angulation that is often encountered in the thoracic aorta. This study assessed the incidence, etiology, and overall effect of misaligned deployment of the Talent Thoracic Stent Graft (TSG) System. Techniques to predict and avoid this complication are discussed.MethodsData collection included pivotal-trial follow-up, direct surveys of centers inside and outside the United States and principal investigators, a targeted literature search, and review of complaint files. Misaligned deployment was considered to occur when the proximal covered or uncovered stent apices of a thoracic stent graft folded back on itself and remained nonparallel to the wall of the aorta after deployment had been completed.ResultsOf about 20,305 deployments to date of the Talent TSG, 24 misaligned deployments were identified for an incidence of 0.1%. Nineteen (79%) events occurred during treatment of degenerative aneurysms or penetrating ulcers, four (17%) during treatment of dissections, and the underlying pathology could not be determined for one patient. The misalignment was noted at the proximal end of the stent graft in 15 patients (63%), and the other 9 events (37%) occurred at the graft overlap junction. Two events were treated intraoperatively, with a second overlapping device placed in one patient and a snare used to reposition the proximal stent in another. Adverse clinical events occurred in three patients and included a persistent type I endoleak, continued false lumen perfusion in a patient with dissection, and delayed retrograde type A dissection in a patient undergoing total arch repair. No intraoperative contrast extravasation or computed tomography evidence of perforation was noted. There were no perioperative deaths or cerebrovascular events, with one report of paraplegia among the 24 patients in this series.ConclusionMisaligned deployment is an unusual phenomenon that tends to occur in the context of certain well-defined anatomic conditions in the thoracic aorta. To date, most of these events have not led to significant adverse sequelae. However, careful patient selection, periprocedural imaging, and case planning can help to identify anatomies in which misaligned opening is likely to occur, allowing physicians to avoid this complication