Análisis histórico-epistemológico de las concepciones de salud desde una perspectiva didáctica : narrando la “historia” de la peste negra medieval

En este trabajo presentamos el caso de la peste negra medieval como insumo para analizar y comparar la potencia didáctica de algunos modelos explicativos de la noción de enfermedad. Comenzamos examinando, desde una perspectiva educativa, algunas de las diferentes concepciones de salud que se han generado a lo largo del tiempo, concepciones que se inscriben en perspectivas uni- o multicausales. Proponemos utilizar la narración de “pequeñas historias” con el propósito de que los y las estudiantes las analicen a partir de diferentes enfoques, de manera que puedan explorar las aportaciones de cada uno de ellos

Holomorphicity of real Kaehler submanifolds

Let $f\colon M^{2n}\to\mathbb{R}^{2n+p}$ denote an isometric immersion of a Kaehler manifold of complex dimension $n\geq 2$ into Euclidean space with codimension $p$. If $2p\leq 2n-1$, we show that generic rank conditions on the second fundamental form of the submanifold imply that $f$ has to be a minimal submanifold. In fact, for codimension $p\leq 11$ we prove that $f$ must be holomorphic with respect to some complex structure in the ambient space.Comment: 18 page

Conformal Kaehler Euclidean submanifolds

Let $f\colon M^{2n}\to\mathbb{R}^{2n+\ell}$, $n \geq 5$, denote a conformal immersion into Euclidean space with codimension $\ell$ of a Kaehler manifold of complex dimension $n$ and free of flat points. For codimensions $\ell=1,2$ we show that such a submanifold can always be locally obtained in a rather simple way, namely, from an isometric immersion of the Kaehler manifold $M^{2n}$ into either $\mathbb{R}^{2n+1}$ or $\mathbb{R}^{2n+2}$, the latter being a class of submanifolds already extensively studied.Comment: 13 Page

Effect of Lactobacillus buchneri LN4637 and Lactobacillus buchneri LN40177 on the aerobic stability, fermentation products, and microbial populations of corn silage under farm conditions.

This study determined the efficacy of the use of 2 commercial inoculants containing Lactobacillus buchneri alone or in combination with homofermentative lactic acid bacteria in improving aerobic stability of corn silage stored in commercial farm silos in northern Italy. In the first survey, samples were collected from 10 farms that did not inoculate their silages and from 10 farms that applied a Pioneer 11A44 inoculant (L. buchneri strain LN4637; Pioneer Hi-Bred International, Des Moines, IA). In the second survey, corn silage samples were collected from 11 farms that did not inoculate their silages and from 11 farms that applied a Pioneer 11CFT inoculant (L. buchneri strain LN40177; Pioneer Hi-Bred International). Inoculants were applied directly through self-propelled forage harvesters, at the recommended rate of 1 g/t of fresh forage, to achieve a final application rate of 1.0 × 10(5) cfu/g of L. buchneri. One corn bunker silo, which had been open for at least 10 d, was examined in detail on each farm. The silages inoculated with L. buchneri had lower concentrations of lactic acid, a lower lactic-to-acetic acid ratio, a lower yeast count, and higher aerobic stability compared with the untreated silages. Unexpectedly, concentrations of acetic acid and 1,2-propanediol, 2 hallmarks of L. buchneri activity, did not differ between treatments and were only numerically higher in the inoculated silages compared with untreated ones, in both surveys. Aerobic stability, on average, was 107 and 121 h in the inoculated silages and 64 and 74 h in the untreated silages, for surveys 1 and 2, respectively, and decreased exponentially as the yeast count in the silage at the time of sampling increased, regardless of treatment. Inoculation with L. buchneri proved to be effective in reducing the yeast count to <2 log cfu/g of silage in 16 of 21 of the studied farm silages, confirming the ability of this inoculum to enhance the aerobic stability of corn silages in farm bunker silos

School scientific argumentation and its contribution to learning the topic «health and disease»

El presente artículo pretende contribuir a la discusión sobre los alcances que tiene la argumentación científica escolar en el aprendizaje de las ciencias experimentales y particularmente de los conceptos de salud y enfermedad. En primer lugar, se articulan diversos aportes teóricos sobre la argumentación y se precisa el posicionamiento ilocutivo de este trabajo. Luego se discute una secuencia didáctica, puesta en aula por una de los autores, que persiguió el objetivo de que estudiantes de enseñanza secundaria argumentaran en torno a la enfermedad llamada porfiria eritropoyética congénita apuntando a audiencias específicas. En la secuencia didáctica se acompañó al estudiantado en la producción de sus argumentos y se apoyó la inclusión de cuatro componentes específicas en sus textos: teórica, lógica, pragmática y retórica. Aquí se analizan las producciones escritas, derivadas de una tarea de retextualización, de un grupo de cinco estudiantes seleccionados intencionadamente, con el fin de identificar posibles aportes del proceso de argumentación al aprendizaje de los conceptos de salud en juego.This article intends to contribute to the discussion around the scope of school scientific argumentation in the learning of science and in particular of the concepts of health and disease. In the first place, various theoretical contributions on argumentation are presented, and the illocutionary positioning of this study is specified. Then, a didactical sequence is discussed; the sequence was implemented in the classroom by one of the authors, and had as aim that secondary-school students argued about the disease called congenital erythropoietic porphyria targeting specific audiences. In the sequence, students were accompanied in the production of their arguments and the inclusion of four specific components in their texts was supported: theoretical, logical, pragmatic and rhetorical. Here, the written productions, derived from a task of re-textualisation, of a group of five intentionally selected students are analysed in order to identify possible contributions of the argumentation process to the learning of the concepts of health that were being discussed

Sialylation on O-linked glycans protects von Willebrand factor from macrophage galactose lectin mediated clearance

Terminal sialylation determines the plasma half-life of von Willebrand factor (VWF). A role for macrophage galactose lectin (MGL) in regulating hyposialylated VWF clearance has recently been proposed. In this study, we showed that MGL influences physiological plasma VWF clearance. MGL inhibition was associated with a significantly extended mean residence time and 3-fold increase in endogenous plasma VWF antigen levels (P<0.05). Using a series of VWF truncations, we further demonstrated that the A1 domain of VWF is predominantly responsible for enabling the MGL interaction. Binding of both full-length and VWF-A1-A2-A3 to MGL was significantly enhanced in the presence of ristocetin (P<0.05), suggesting that the MGL-binding site in A1 is not fully accessible in globular VWF. Additional studies using different VWF glycoforms demonstrated that VWF O-linked glycans, clustered at either end of the A1 domain, play a key role in protecting VWF against MGLmediated clearance. Reduced sialylation has been associated with pathological, increased clearance of VWF in patients with von Willebrand disease. Herein, we demonstrate that specific loss of α2-3 linked sialylation from O-glycans results in markedly increased MGL-binding in vitro, and markedly enhanced MGL-mediated clearance of VWF in vivo. Our data further show that the asialoglycoprotein receptor (ASGPR) does not have a significant role in mediating the increased clearance of VWF following loss of O-sialylation. Conversely however, we observed that loss of N-linked sialylation from VWF drives enhanced circulatory clearance predominantly via the ASGPR. Collectively, our data support the hypothesis that in addition to regulating physiological VWF clearance, the MGL receptor works in tandem with ASGPR to modulate enhanced clearance of aberrantly sialylated VWF in the pathogenesis of von Willebrand disease

Sound archaeology: terminology, Palaeolithic cave art and the soundscape

This article is focused on the ways that terminology describing the study of music and sound within archaeology has changed over time, and how this reflects developing methodologies, exploring the expectations and issues raised by the use of differing kinds of language to define and describe such work. It begins with a discussion of music archaeology, addressing the problems of using the term ‘music’ in an archaeological context. It continues with an examination of archaeoacoustics and acoustics, and an emphasis on sound rather than music. This leads on to a study of sound archaeology and soundscapes, pointing out that it is important to consider the complete acoustic ecology of an archaeological site, in order to identify its affordances, those possibilities offered by invariant acoustic properties. Using a case study from northern Spain, the paper suggests that all of these methodological approaches have merit, and that a project benefits from their integration

Further characterization of ADAMTS-13 inactivation by thrombin

Background: The multimeric size and platelet-tethering function of von Willebrand factor (VWF) are modulated by the plasma metalloprotease, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13). In vitro ADAMTS-13 is susceptible to proteolytic inactivation by thrombin. Objectives: In this study, we aimed to characterize the inactivation of ADAMTS-13 by thrombin and to assess its physiological significance. Methods and results: By N-terminal sequencing of cleavage products, and by mutagenesis, we identified the principal thrombin cleavage sites in ADAMTS-13 as R257 and R1176. Using a library of 76 thrombin mutants, we highlighted the functional importance of exosite I on thrombin in the proteolysis of ADAMTS-13. Proteolysis of ADAMTS-13 by thrombin caused an 8-fold reduction in its affinity for VWF that contributed to its loss of VWF-cleaving function. Intriguingly, thrombin-cleaved ADAMTS-13 both bound and proteolyzed a short recombinant VWF A2 domain substrate (VWF115) normally. Following activation of coagulation in normal plasma, endogenous ADAMTS-13, but not added ADAMTS-13, appeared resistant to coagulation-induced fragmentation. An estimation of the Km for ADAMTS-13 proteolysis by thrombin was appreciably higher than the physiological concentration of ADAMTS-13. This was corroborated by the comparatively low affinity of ADAMTS-13 for thrombin (KD 95 nm). Conclusions: Together, our data suggest that ADAMTS-13 is protected from rapid proteolytic inactivation by thrombin in normal plasma. Whether this remains the case under pathological situations involving elevated/sustained generation of thrombin remains unclear

‘The Rest is Silence’:Psychogeography, Soundscape and Nostalgia in Pat Collins’ Silence

Guy Debord defines the term psychogeography as 'the study of the precise laws and specific effects of the geographical environment, consciously organised or not, on the emotions and behaviour of individuals' (Debord 1955: 23). Similar to the belief of psychogeographers that the geography of an environment has a psychological effect on the human mind, proponents of acoustic ecology such as R. Murray Schafer hold that humans are affected by the sound of the environment in which they find themselves. Further to this, they examine the extent to which soundscapes can be shaped by human behaviour. Recently a body of Irish films has emerged that directly engages with the Irish soundscape and landscape on a psychogeographical level. Rather than using landscape as a physical space for the locus of action, these representations of the Irish landscape allow for an engagement with the aesthetic effects of the geographical landscape as a reflection of the psychological states of the protagonists. Bearing this in mind, this article examines how Silence (Collins 2012) arguably demonstrates the most overt and conscious incursion into this area to date. It specifically interrogates how the filmic representation of the psychogeography and soundscape of the Irish rural landscape can serve to express emotion, alienation and nostalgia, thus confronting both the Irish landscape and the weight of its associated history