The Lingering Killer: Agent Orange

This paper explores the utilization of the chemical herbicide, Agent Orange, as it was sprayed over Vietnam during the Vietnam War in 1961 to 1971. The United States government, military, and corporations acted irresponsibly by creating the chemical and spraying it as a war tactic. The outcome of the spraying includes detrimental socioeconomic impacts, environmental degradation, and health problems. The socioeconomic impact is explained with statistics and an explanation of loss of job and education capabilities. With data on the destroyed trees and vegetation, this paper demonstrates the degree to which the environment faced harm. The health effects of Agent Orange are detailed by listing the diseases associated with the chemical. The struggle for justice, reparations, and policies remedying the harmful effects of Agent Orange are explored. Conclusions are made about the failing human rights record of the United States

Management of reproductive seasonality in small ruminants

The majority of the species of small ruminants are seasonal reproducers, which implies that there are changes in their reproductive physiology that determine the existence of a reproductive season, in which the females cycle and ovulate and the males present their maximum reproductive activity, and an anestrus season, in which the females do not present estrous cycles and the males decrease their level of reproductive activity. The reproductive seasonality is an evolutionary consequence of the species so that the births occur at the most favorable moment for the survival of their offspring, which in temperate climates usually occurs in the spring. In the case of rams and goats there are annual variations in the concentration of LH, FSH and testosterone, which generates changes in the characteristics of semen and sexual behavior. For example, during the reproductive season the diameter of the seminiferous tubules and the epididymis increases, the number of spermatogonia in the seminiferous tubules, and the size, weight and activity of the secondary sex glands. This determines that the males of many breeds of sheep and goats have a low capacity to breed female cycling during this period

Endocrine and Ovarian Changes in Response to the Ram Effect in Medroxyprogesterone Acetate-primed Corriedale Ewes During the Breeding and Nonbreeding Season

Two experiments were performed to determine the endocrine and ovarian changes in medroxyprogesterone acetate (MAP)-primed ewes after ram introduction. Experiment 1 was performed during the mid-breeding season with 71 ewes primed with an intravaginal MAP sponge for 12 days. While the control (C) ewes (n = 35) were in permanent contact with rams, the ram effect (RE) ewes (n = 36) were isolated for 34 days prior to contact with rams. At sponge withdrawal, all ewes were joined with eight sexually experienced marking Corriedale rams and estrus was recorded over the next 4 days. The ovaries were observed by laparoscopy 4–6 days after estrus. Four weeks later, pregnancy was determined by transrectal ultrasonography. In eight ewes from each group, ovaries were ultrasonographically scanned; FSH, LH, and estradiol-17β were measured every 12 hours until ovulation or 96 hours after estrus. The response to the rams was not affected by the fact that ewes had been kept or not in close contact with males before teasing. No differences were found in FSH, LH, estradiol-17β concentrations, growth of the ovulatory follicle, onset of estrus, ovulation rate, or pregnancy rate. Experiment 2 was performed with 14 ewes during the nonbreeding season. Ewes were isolated from rams for 1 month, and received a 6-day MAP priming. Ovaries were ultrasonographically scanned every 12 hours, and FSH, LH, estradiol-17β, and progesterone were measured. Ewes that ovulated and came into estrus had higher FSH and estradiol-17β levels before introduction of the rams than did ewes that had a silent ovulation. The endocrine pattern of the induced follicular phase of ewes that came into estrus was more similar to a normal follicular phase, than in ewes that had a silent ovulation. The follicle that finally ovulated tended to emerge earlier and in a more synchronized fashion in those ewes that did come into estrus. All ewes that ovulated had an LH surge and reached higher maximum FSH levels than ewes that did not ovulate, none of which had an LH surge. We conclude that (a) the effect of ram introduction in cyclic ewes treated with MAP may vary depending on the time of the breeding season at which teasing is performed; (b) patterns of FSH, and estradiol-17β concentrations, as indicators of activity of the reproductive axis, may be used to classify depth of anestrus; and (c) the endocrine pattern of the induced follicular phase, which is related to the depth of anestrus, may be reflected in the behavioral responses to MAP priming and the ram effect

Minimising the stress of weaning of beef calves: a review

Weaning of beef calves is usually done abruptly and early compared to the natural weaning of the species, and is associated with simultaneous exposure of calves to a range of social and environmental stressors. Behavioural and physiological responses to weaning indicate detrimental effects on the welfare of these animals. The development and assessment of weaning methods aiming at reducing or avoiding this problem must be supported by scientific knowledge of the morphological, physiological and psychological mechanisms involved in the establishment, maintenance and braking of the cow-calf bond. Solutions also depend on the understanding of the various stressors associated with weaning, among which are the change in diet, cessation of nursing, separation from the dam, the change to a new spatial environment and the need for social reorganization following removal of the adults from the group. This review discusses these issues and assesses the effectiveness of the methods so far proposed for improving the welfare of beef calves during the weaning period

Managing reproductive seasonality in small ruminants

Most species and breeds of small ruminants, especially sheep and goats, have seasonal reproduction, meaning that females cycle for part of the year and remain in anestrous during the remaining part, while males increase and decrease in reproductive activity in sync with females. This is regulated primarily by variations in the length of daylight. During darkness, the hormone melatonin is secreted and synchronizes physiological processes with environmental conditions. Limits are thus placed on the months of the year in which these animals can reproduce and, therefore, the availability of lambs or kids. This review briefly introduces the principal techniques used to modify the seasonal pattern in sheep and goats, and for several of these, recent technical information is included. Hormonal methods, basically involve pharmacological estrous cycle creation in a female (progesterone + gonadotropin) or placement of subcutaneous implants that release melatonin. In the male use of these implants is also effective, and recent information suggests the potential use of equine chorionic gonadotrophin (eCG) to improve reproductive performance outside the normal season. Information is presented about stimuli that alter the physiology of the animal, such as manipulating the number of hours of light or darkness that an animal is exposed to, thus, allowing reversal of the seasonal effects in both males and females. Managing the social environment of the animals can also be effective in modifying seasonality. The male effect consists of suddenly exposing previously isolated anestrous females to rams and bucks, which induces neuroendocrinal changes that can lead to the expression of estrus accompanied by ovulation. The stimulus caused by the presence of other cycling females is also effective to induce ovulation in anestrus females, especially goat does, while in the case of ewes, this occurs after close physical contact with the cycling animals. Conversely, sudden contact of rams and bucks with females in estrus induces substantial increases in the secretion of gonadotropins and androgens and, if the stimulus is sufficiently maintained, it is possible to modify the reproductive status of these males. Lastly, the advantages and disadvantages of each of these technologies is discussed

PREDICCIÓN Y MITIGACIÓN DE LAS EMISIONES DE METANO DE LOS RUMIANTES

Livestock production systems emit enteric methane originated in rumen fermentation. There is growing interest in controlling methane production in the rumen because of its effects on climate change and the energy utilization inefficiency implied by methane losses to the atmosphere. There are currently several strategies of enteric methane abatement being investigated: nutrition, selection of low emitting animals, intensification of production, plant secondary compounds, chemical inhibitors, nitrate, immunization, defaunation, reductive acetogenesis, and bacteriophages. Research is also performed in developing predictive models of methane emissions based on animal production or diet composition, which can be used to build inventories of greenhouse gases emissions by country, region or sector.Los sistemas ganaderos son altos emisores de metano entérico proveniente de la fermentación en el rumen. Existe interés creciente en controlar la producción de metano en el rumen debido a sus efectos ambientales y la pérdida de energía que supone. Varias estrategias de mitigación de la producción de metano por los rumiantes están siendo investigadas, como alimentación, selección de animales de baja emisión, intensificación de la producción animal, compuestos secundarios de plantas, inhibidores químicos, nitrato, inmunización, defaunación, acetogenesis reductiva, y bacteriófagos. Adicionalmente, se investiga en el desarrollo de modelos predictivos de la producción de metano entérica en función de la producción de leche o la composición de la dieta para construir inventarios de emisiones de gases de efecto invernadero por países, regiones o sectores

Impacto científico dos pesquisadores: contribuição vs h-index?

Durante los últimos años aumentó el uso de los índices de impacto por parte de instituciones para evaluar a las revistas científicas, la productividad de las instituciones, o a los investigadores. En el presente artículo se discute la validez del uso de estos indicadores para evaluar la trayectoria académica de los investigadores. El indicador más utilizado para evaluar a los investigadores es el índice h, el que se basa en la cantidad de artículos citados al menos una mínima cantidad de veces h. Este índice no considera la producción que está por debajo de ese valor, el impacto o aporte individual del investigador, su ubicación como autor en los artículos, los años de trabajo del mismo, el área temática, o el tiempo que requieren algunos artículos, en algunos temas, para efectivamente impactar a nivel de la comunidad científica. Se utiliza el perfil de citas de Einstein y del artículo de Watson y Crick (1953) en que se describe la doble hélice del ADN como ejemplos que muestran que el mayor impacto puede no ser inmediato y requerir años de desarrollo del área, a pesar de que su importancia fuera clave para el desarrollo de la misma. Los índices son formas de cuantificar impactos, pero el uso y abuso de los mismos, y sobre todo el uso para considerar aspectos que no son los que miden, puede llevar a conclusiones equivocadas. Si bien son parte de las herramientas disponibles para medir productividad científica, los mismos deben ser considerados en función de lo que efectivamente miden en base a los insumos y criterios en que se basan. Por tanto, es importante que los sistemas de evaluación científica los pongan en contexto al considerarlos para la evaluación del desempeño académico.In recent years, the use of impact indexes by institutions to evaluate scientific journals, the productivity of institutions, or researchers, has increased. This article discusses the validity of the use of these indicators to assess the academic trajectory of researchers. The most widely used indicator to evaluate researchers is the h-index, which is based on the number of articles cited at least a minimum number of times h. This index does not consider the production that is below that value, the impact or individual contribution of the researcher, the author’s positions in the articles, the time during which those articles were published, the subject area, or the time that some articles require in some topics to effectively impact at the level of the scientific community. Einstein's citation profile and Watson and Crick's (1953) article describing the DNA double helix are used as examples showing that the greatest impact may not be immediate and may require years of development in the scientific area, despite that its importance was key to its development. The indices are ways of quantifying impacts, but their use and abuse, and especially their use to consider aspects that are not what they measure, can lead to wrong conclusions. Although they are part of the tools available to measure scientific productivity, they must be considered based on what they measure based on the inputs and criteria on which they are based. Therefore, it is important that scientific evaluation systems put them in context when considering them for the evaluation of academic performance.Nos últimos anos, aumentou o uso de índices de impacto por instituições para avaliar periódicos científicos, a produtividade das instituições ou dos pesquisadores. Este artigo discute a validade do uso desses indicadores para avaliar a trajetória acadêmica de pesquisadores. O indicador mais utilizado para avaliar pesquisadores é o índice h, que se baseia no número de artigos citados pelo menos um número mínimo de vezes h. Este índice não considera a produção abaixo desse valor, o impacto ou contribuição individual do pesquisador, sua posição como autor nos artigos, seus anos de trabalho, a área temática ou o tempo que alguns artigos exigem, em alguns tópicos, para impactar efetivamente a nível da comunidade científica. O perfil de citações de Einstein e o artigo de Watson e Crick (1953) descrevendo a dupla hélice do DNA são usados ​​como exemplos mostrando que o maior impacto pode não ser imediato e pode exigir anos de desenvolvimento da área, apesar de sua importância ter sido fundamental para seu desenvolvimento. Os índices são formas de quantificar impactos, mas seu uso e abuso, e principalmente para considerar aspectos que não são o que eles medem, pode levar a conclusões equivocadas. Embora façam parte das ferramentas disponíveis para medir a produtividade científica, devem ser consideradas com base no que realmente medem com base nos insumos e critérios nos quais se baseiam. Portanto, é importante que os sistemas de avaliação científica os coloquem em contexto ao considerá-los para a avaliação do desempenho acadêmico

Comportamiento homosexual en rumiantes machos. Revisión

In several male ruminants, including both, domestic and wild species, it has been reported the presence of homosexualbehaviour  between  males.  The  aim  of  this  review  was  to  summarize  the  information  about  neuroendocrinologicaldifferences  between  homo  and  heterosexual  individuals,  and  the  relationship  between  homosexual  behaviour  andsexual steroid concentration. Moreover, we present information that link homosexual behavior with social dominance,age,  social  environment  during  the  developmental  period,  and  environment  disturbances.  Therefore,  we  includeinformation  about  other  physiologic  aspects,  such  as  reproductive  seasonality,  including  unpublished  informationabout  seasonal  changes  in  domestic  rams  and  captive  male  Iberian  ibex,  and  the  relationship  between  seasonalchanges  in  testosterone  and  behaviour.  Other  topic  discussed  is  the  “buller  syndrome”,  which  is  commonly  observedin  steers,  in  which  is  observed  that  some  males  are  repeatedly  mounted  by  others  males.  In  brief,  homosexualbehaviour  in  male  ruminants  is  multietiologic,  and  some  aspects  are  understudied,  so  the  interpretation  may  becautiously  considered  before  deep  studies  are  developed.En varias especies de rumiantes, tanto domésticos como silvestres, se ha reportado la existencia del comportamiento homosexual entre los machos. El objetivo de esta revisión fue sintetizar la información disponible sobre las diferencias neuroendocrinas entre individuos homo y heterosexuales, y la relación entre la presencia del comportamiento homosexual y la concentración de esteroides sexuales. A su vez, se presenta información que vincula el comportamiento homosexual con la dominancia social, la edad, el ambiente social durante el desarrollo, y los disturbios ambientales. También se analiza como varía el comportamiento homosexual de acuerdo a la estacionalidad reproductiva. Además, se incluye información original sobre la estacionalidad del comportamiento homosexual en carneros domésticos, y de machos de cabra montesa, y su vínculo con la secreción de testosterona. Otro aspecto discutido es el “síndrome de buller” en novillos, individuos que son sistemáticamente montados por otros, y algunos de los factores asociados con la ocurrencia de este síndrome. En síntesis, el comportamiento homosexual en los rumiantes machos tiene un origen etiológico diverso, estando algunos aspectos aún poco estudiados, por lo que toda interpretación debe ser considerada con cautela, siendo por lo tanto un campo de estudio a profundizar