Fragmentos de un discurso no amoroso: Thomas Jefferson y la América Hispana. Una aproximación a las relaciones sur-norte (Estudios)

A lo largo del siglo XIX, el pensamiento de Thomas Jefferson fue un punto de encuentro entre Hispanoamérica y los Estados Unidos. Esas aproximaciones estuvieron cruzadas al mismo tiempo por un sentido de admiración y por una serie de temores. Este ensayo reúne y analiza algunos de los fragmentos en que la imagen de Jefferson, su pensamiento y sus escritos evidencian esa relación ambigua en escritores decimonónicos clave como Andrés Bello, Domingo Sarmiento y Esteban Echeverría. Por otra parte, el ensayo reúne fragmentos de las cartas escritas por Jefferson a Alexander von Humboldt, en las que manifiesta su escaso interés por las independencias hispanoamericanas y su desconocimiento sobre los procesos ilustrados que allí se habían desarrollado.

Metáforas e intertextos de la enfermedad: suicidio y homoerotismo adolescente en las novelas Conquering Venus, de Collin Kelley y Suicide Notes, de Michael Thomas Ford

En el mundo cada cinco minutos se produce un suicidio en adolescentes por problemas inherentes a su sexualidad. Frente a este escenario la genealogía de los discursos médico, jurídico y literario se entreteje apretando los hilos, convirtiéndose en cábala del suicidio; un reflejo difuso de una realidad menos ficcional y más dolorosa. A pesar de las cifras alarmantes, no se ha trabajado el tema; menos aún con la perspectiva de encontrar relación entre los discursos históricos que en su búsqueda de poder y control han dibujado sobre los cuerpos, representaciones de una disciplina heterosexual. Es indispensable una perspectiva cualitativa, reflexiones que aporten a una práctica ética diferente, que incluya los nuevos cuerpos filosóficos, legales, concibiendo al adolescente como sujeto, con la agencia que deben tener sus cuerpos. En contraste en la literatura (¿mundo ficticio?) se describe y resignifica de manera exhaustiva esta realidad, rescatando la capacidad creativa y re-creativa del lenguaje. Esto por un lado permite analizar los contextos y coyunturas sociales, culturales; y, por otro interpretar los imaginarios sociales y las metáforas que refuerzan este contexto. Como mencionara Stuart Hall, a través de la representación conectamos el lenguaje al sentido y la cultura. Y esto nos licencia a referirnos al mundo real pero también a un mundo ficticio. Esta exploración pretende aportar a esta problemática mediante la descripción de esa compleja interseccionalidad y la identificación de posibles intersticios en el lenguaje que pudieran dar sentido y descodificar ciertas incertidumbres, contribuir a cambios micro sociales y, quizás, conducir a lo que pudiera ser el comienzo de un diálogo más amplio que empuje posicionamientos y cambios estructurales, frente a discursos vetustos que siempre encuentran mecanismos para reinventarse. ¿Cómo se representan y entretejen los discursos de homoerotismo1 adolescente y suicidio representados en las novelas Conquering Venus de Collin Kelley, Suicide Notes de Michael Thomas Ford? Lo podremos averiguar examinando las matrices discursivas del homoerotismo y su castigo, la homosexualidad; analizando el suicidio como un acto humano complejo, incomprensible, un tabú en nuestra sociedad, e identificando en las novelas escogidas, las intersecciones entre homoerotismo y tendencias suicidas en el cuerpo adolescente.

Tolerance of ruminant animals to high dose in-feed administration of a selenium-enriched yeast

The objective of the study was to determine if there were adverse effects on animal health and performance when a range of ruminant animals species were fed at least 10 times the maximum permitted European Union (EU) selenium (Se) dietary inclusion rate (0.568 mg Se/kg DM) in the form of selenium enriched yeast (SY) derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060. In a series of studies, dairy cows, beef cattle, calves and lambs were offered either a control diet which contained no Se supplement or a treatment diet which contained the same basal feed ingredients plus a SY supplement which increased total dietary Se from 0.15 to 6.25, 0.20 to 6.74, 0.15 to 5.86 and 0.14 to 6.63 mg Se/kg DM, respectively. The inclusion of the SY supplement (P < 0.001) increased whole blood Se concentrations, reaching maximum mean values of 716, 1,505, 1,377, and 724 ng Se/mL for dairy cattle, beef cattle, calves and lambs, respectively. Selenomethionine accounted for 10% of total whole blood Se in control animals whereas the proportion in SY animals ranged between 40 and 75%. Glutathione peroxidase (EC 1.11.1.9) activity was higher (P < 0.05) in SY animals when compared with controls. A range of other biochemical and hematological parameters were assessed, but few differences of biological significance were established between treatments groups. There were no differences between treatment groups within each species with regard to animal physical performance or overall animal health. It was concluded that there were no adverse effects on animal health, performance and voluntary feed intake to the administration of at least ten times the EU maximum, or approximately twenty times the US FDA permitted concentration of dietary Se in the form of SY derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060.

Selenium supplementation of lactating dairy cows: effects on milk production and total selenium content and speciation in blood, milk and cheese

Forty-multiparous Holstein cows were used in a 16-wk continuous design study to determine the effects of either selenium (Se) source, selenized yeast (SY) (derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060 Sel-Plex®) or sodium selenite (SS), or inclusion rate of SY on Se concentration and speciation in blood, milk and cheese. Cows received ad libitum a TMR with 1:1 forage:concentrate ratio on a dry matter (DM) basis. There were four diets (T1-T4) which differed only in either source or dose of Se additive. Estimated total dietary Se for T1 (no supplement), T2 (SS), T3 (SY) and T4 (SY) was 0.16, 0.30, 0.30 and 0.45 mg/kg DM, respectively. Blood and milk samples were taken at 28 day intervals and at each time point there were positive linear effects of SY on Se concentration in blood and milk. At day 112 blood and milk Se values for T1-T4 were 177, 208, 248, 279 ± 6.6 and 24, 38, 57, 72 ± 3.7 ng/g fresh material, respectively and indicate improved uptake and incorporation of Se from SY. While selenocysteine (SeCys) was the main selenised amino acid in blood its concentration was not markedly affected by treatment, but the proportion of total Se as selenomethionine (SeMet) increased with increasing inclusion rate of SY. In milk, there were no marked treatment effects on SeCys content, but Se source had a marked effect on the proportion of total Se as SeMet. At day 112 replacing SS (T2) with SY (T3) increased the SeMet concentration of milk from 36 to 111 ng Se/g and its concentration increased further to 157 ng Se/g as the inclusion rate of SY increased further (T4) to provide 0.45 mg Se/kg TMR. Neither Se source nor inclusion rate effected the keeping quality of milk. At day 112, milk from T1, T2, and T3 was made into a hard cheese and Se source had a marked effect on total Se and the proportion of total Se comprised as either SeMet or SeCys. Replacing SS (T2) with SY (T3) increased total Se, SeMet and SeCys content from 180 to 340 ng Se/g, 57 to 153 ng Se/g and 52 to 92 ng Se/g, respectively. Key words: dairy cow, milk and cheese, selenomethionine, selenocysteine, milk keeping quality

Selenium supplementation of lactating dairy cows: Effect on selenium concentration in blood, milk, urine and feces

The objectives were to determine effects of graded levels of selenized yeast derived from a specific strain of Saccharomyces cerevisiae (CNCM I-3060) on animal performance and in selenium concentrations in the blood, milk, feces, and urine of dairy cows compared with sodium selenite; and to provide preliminary data on the proportion of selenium as selenomethionine in the milk and blood. Twenty Holstein cows were used in a 5 × 5 Latin square design study in which all cows received the same total mixed rations, which varied only in source or concentration of dietary selenium. There were 5 experimental treatments. Total dietary selenium of treatment 1, which received no added selenium, was 0.15 mg/kg of dry matter, whereas values for treatments 2, 3, and 4, derived from selenized yeast, were 0.27, 0.33, and 0.40 mg/kg of dry matter, respectively. Treatment 5 contained 0.25 mg of selenium obtained from sodium selenite/kg of dry matter. There were no significant treatment effects on animal performance, and blood chemistry and hematology showed few treatment effects. Regression analysis noted significant positive linear effects of increasing dietary selenium derived from selenized yeast on selenium concentrations in the milk, blood, urine, and feces. In addition, milk selenium results indicated improved bioavailability of selenium from selenized yeast, compared with sodium selenite. Preliminary analyses showed that compared with sodium selenite, the use of selenized yeast increased the concentration of selenomethionine in the milk and blood. There was no indication of adverse effects on cow health associated with the use of selenized yeast.