1,779 research outputs found
Variation in the transfer of radionuclide to freshwater fish: phylogeny or feeding strategy?
For both terrestrial vascular plants and marine organisms if has been demonstrated the differences in radionuclide transfer between species can be related to their evolutionary history or phylogeny. Relationships between phylogeny and radionuclide transfer offer a potential approach to help to derive best estimate values if data for a given species-radionuclide are not available.
In this paper we describe the analyses of data for radionuclide transfer to freshwater fish from a data base recently compiled to support activities of both the IAEA and ICRP. There are sufficient data in the database to test the hypothesis that radionuclide transfer can be related to the evolutionary of freshwater fish for caesium, strontium and uranium. For instance, the database contains 750 entries for caesium considering nearly 70 species of fish. Initial results indicate that phylogeny does explain some of the variation in radionuclide transfer between species of fish. However, feeding strategy also explains variation in radionuclide transfer between species. In this paper we will compare our results to establish if phylogeny or feeding strategy is the most useful predictor of radionuclide transfer to freshwater fish
Contextualizing the relevance of basic sciences: small-group simulation with debrief for first- and second-year medical students in an integrated curriculum.
There has been a call for increased integration of basic and clinical sciences during preclinical years of undergraduate medical education. Despite the recognition that clinical simulation is an effective pedagogical tool, little has been reported on its use to demonstrate the relevance of basic science principles to the practice of clinical medicine. We hypothesized that simulation with an integrated science and clinical debrief used with early learners would illustrate the importance of basic science principles in clinical diagnosis and management of patients.Small groups of first- and second-year medical students were engaged in a high-fidelity simulation followed by a comprehensive debrief facilitated by a basic scientist and clinician. Surveys including anchored and open-ended questions were distributed at the conclusion of each experience.The majority of the students agreed that simulation followed by an integrated debrief illustrated the clinical relevance of basic sciences (mean ± standard deviation: 93.8% ± 2.9% of first-year medical students; 96.7% ± 3.5% of second-year medical students) and its importance in patient care (92.8% of first-year medical students; 90.4% of second-year medical students). In a thematic analysis of open-ended responses, students felt that these experiences provided opportunities for direct application of scientific knowledge to diagnosis and treatment, improving student knowledge, simulating real-world experience, and developing clinical reasoning, all of which specifically helped them understand the clinical relevance of basic sciences.Small-group simulation followed by a debrief that integrates basic and clinical sciences is an effective means of demonstrating the relationship between scientific fundamentals and patient care for early learners. As more medical schools embrace integrated curricula and seek opportunities for integration, our model is a novel approach that can be utilized
Consistency in Regularizations of the Gauged NJL Model at One Loop Level
In this work we revisit questions recently raised in the literature
associated to relevant but divergent amplitudes in the gauged NJL model. The
questions raised involve ambiguities and symmetry violations which concern the
model's predictive power at one loop level. Our study shows by means of an
alternative prescription to handle divergent amplitudes, that it is possible to
obtain unambiguous and symmetry preserving amplitudes. The procedure adopted
makes use solely of {\it general} properties of an eventual regulator, thus
avoiding an explicit form. We find, after a thorough analysis of the problem
that there are well established conditions to be fulfiled by any consistent
regularization prescription in order to avoid the problems of concern at one
loop level.Comment: 22 pages, no figures, LaTeX, to appear in Phys.Rev.
An SPR based sensor for allergens detection
A simple, sensitive and label-free optical sensor method was developed for allergens analysis using α-casein as the biomarker for cow's milk detection, to be used directly in final rinse samples of cleaning in place systems (CIP) of food manufacturers. A Surface Plasmon Resonance (SPR) sensor chip consisting of four sensing arrays enabling the measurement of samples and control binding events simultaneously on the sensor surface was employed in this work. SPR offers several advantages in terms of label free detection, real time measurements and superior sensitivity when compared to ELISA based techniques. The gold sensor chip was used to immobilise α-casein-polyclonal antibody using EDC/NHS coupling procedure. The performance of the assay and the sensor was first optimised and characterised in pure buffer conditions giving a detection limit of 58 ng mL−1 as a direct binding assay. The assay sensitivity can be further improved by using sandwich assay format and amplified with nanoparticles. However, at this stage this is not required as the detection limit achieved exceeded the required allergens detection levels of 2 µg mL−1 for α-S1-casein. The sensor demonstrated good selectivity towards the α-casein as the target analyte and adequate recoveries from CIP final rinse wash samples. The sensor would be useful tool for monitoring allergen levels after cleaning procedures, providing additional data that may better inform upon wider food allergen risk management decision(s) that are made by food manufacturer. In particular, this sensor could potentially help validate or optimise cleaning practices for a given food manufacturing process
Anomalies in Ward Identities for Three-Point Functions Revisited
A general calculational method is applied to investigate symmetry relations
among divergent amplitudes in a free fermion model. A very traditional work on
this subject is revisited. A systematic study of one, two and three point
functions associated to scalar, pseudoscalar, vector and axial-vector densities
is performed. The divergent content of the amplitudes are left in terms of five
basic objects (external momentum independent). No specific assumptions about a
regulator is adopted in the calculations. All ambiguities and symmetry
violating terms are shown to be associated with only three combinations of the
basic divergent objects. Our final results can be mapped in the corresponding
Dimensional Regularization calculations (in cases where this technique could be
applied) or in those of Gertsein and Jackiw which we will show in detail. The
results emerging from our general approach allow us to extract, in a natural
way, a set of reasonable conditions (e.g. crucial for QED consistency) that
could lead us to obtain all Ward Identities satisfied. Consequently, we
conclude that the traditional approach used to justify the famous triangular
anomalies in perturbative calculations could be questionable. An alternative
point of view, dismissed of ambiguities, which lead to a correct description of
the associated phenomenology, is pointed out.Comment: 26 pages, Revtex, revised version, Refs. adde
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