Exceptional Record of Mid-Pleistocene Vertebrates Helps Differentiate Climatic from Anthropogenic Ecosystem Perturbations

Mid-Pleistocene vertebrates in North America are scarce but important for recognizing the ecological effects of climatic change in the absence of humans. We report on a uniquely rich mid-Pleistocene vertebrate sequence from Porcupine Cave, Colorado, which records at least 127 species and the earliest appearances of 30 mammals and birds. By analyzing \u3e20,000 mammal fossils in relation to modern species and independent climatic proxies, we determined how mammal communities reacted to presumed glacial-interglacial transitions between 1,000,000 and 600,000 years ago. We conclude that climatic warming primarily affected mammals of lower trophic and size categories, in contrast to documented human impacts on higher trophic and size categories historically. Despite changes in species composition and minor changes in small-mammal species richness evident at times of climatic change, overall structural stability of mammal communities persisted \u3e600,000 years before human impacts

To the rescue of indigenous children. Anthropological reflections stemming from a UNICEF campaign in Argentina

This article presents an anthropological approach to the "Campaign for the Indigenous Children and Adolescents' Rights" launched by UNICEF Argentina in September 2009, with the purpose of analyzing the social constructions of childhood, of indigenous issues and the meanings of "rights" that are there implied. Far from human rights ontological perspectives, we address this Campaign as a mechanism that constructs the idea of indigenous children as subjects of rights in specific ways. For this purpose, we examine the making process of the Campaign and its contents, attempting to clarify the precise rights and representations of indigenous children claimed therein, as well as the tensions emerged in the producing and presenting process.En este trabajo abordaremos, desde una perspectiva antropológica, la “campaña por los derechos de la niñez y la adolescencia indígena” lanzada por UNICEF Argentina en 2009, con el fi n de problematizar las construcciones de niñez, de la cuestión indígena y de la noción de “derechos” que allí se ponen en juego. Distanciándonos de concepciones ontológicas sobre los derechos humanos, analizaremos esta campaña en tanto dispositivo cuyo efecto es la construcción de los niños indígenas como sujetos de derechos de maneras específi cas. Para ello, indagamos en el modo en que fue ésta elaborada, así como en sus contenidos, procurando explicar qué derechos y qué representaciones de los niños indígenas se visibilizaron a través de ella y las tensiones suscitadas en su proceso de armado y presentación.Facultad de Trabajo Socia

To the rescue of indigenous children. Anthropological reflections stemming from a UNICEF campaign in Argentina

This article presents an anthropological approach to the "Campaign for the Indigenous Children and Adolescents' Rights" launched by UNICEF Argentina in September 2009, with the purpose of analyzing the social constructions of childhood, of indigenous issues and the meanings of "rights" that are there implied. Far from human rights ontological perspectives, we address this Campaign as a mechanism that constructs the idea of indigenous children as subjects of rights in specific ways. For this purpose, we examine the making process of the Campaign and its contents, attempting to clarify the precise rights and representations of indigenous children claimed therein, as well as the tensions emerged in the producing and presenting process.En este trabajo abordaremos, desde una perspectiva antropológica, la “campaña por los derechos de la niñez y la adolescencia indígena” lanzada por UNICEF Argentina en 2009, con el fi n de problematizar las construcciones de niñez, de la cuestión indígena y de la noción de “derechos” que allí se ponen en juego. Distanciándonos de concepciones ontológicas sobre los derechos humanos, analizaremos esta campaña en tanto dispositivo cuyo efecto es la construcción de los niños indígenas como sujetos de derechos de maneras específi cas. Para ello, indagamos en el modo en que fue ésta elaborada, así como en sus contenidos, procurando explicar qué derechos y qué representaciones de los niños indígenas se visibilizaron a través de ella y las tensiones suscitadas en su proceso de armado y presentación.Facultad de Trabajo Socia

Kant's conception of proper science

Kant is well known for his restrictive conception of proper science. In the present paper I will try to explain why Kant adopted this conception. I will identify three core conditions which Kant thinks a proper science must satisfy: systematicity, objective grounding, and apodictic certainty. These conditions conform to conditions codified in the Classical Model of Science. Kant's infamous claim that any proper natural science must be mathematical should be understood on the basis of these conditions. In order to substantiate this reading, I will show that only in this way it can be explained why Kant thought (1) that mathematics has a particular foundational function with respect to the natural sciences and (2) as such secures their scientific status. © 2009 The Author(s)

Disrupted habenula function in major depression.

The habenula is a small, evolutionarily conserved brain structure that plays a central role in aversive processing and is hypothesised to be hyperactive in depression, contributing to the generation of symptoms such as anhedonia. However, habenula responses during aversive processing have yet to be reported in individuals with major depressive disorder (MDD). Unmedicated and currently depressed MDD patients (N=25, aged 18-52 years) and healthy volunteers (N=25, aged 19-52 years) completed a passive (Pavlovian) conditioning task with appetitive (monetary gain) and aversive (monetary loss and electric shock) outcomes during high-resolution functional magnetic resonance imaging; data were analysed using computational modelling. Arterial spin labelling was used to index resting-state perfusion and high-resolution anatomical images were used to assess habenula volume. In healthy volunteers, habenula activation increased as conditioned stimuli (CSs) became more strongly associated with electric shocks. This pattern was significantly different in MDD subjects, for whom habenula activation decreased significantly with increasing association between CSs and electric shocks. Individual differences in habenula volume were negatively associated with symptoms of anhedonia across both groups. MDD subjects exhibited abnormal negative task-related (phasic) habenula responses during primary aversive conditioning. The direction of this effect is opposite to that predicted by contemporary theoretical accounts of depression based on findings in animal models. We speculate that the negative habenula responses we observed may result in the loss of the capacity to actively avoid negative cues in MDD, which could lead to excessive negative focus

Amygdala inputs to prefrontal cortex guide behavior amid conflicting cues of reward and punishment

Orchestrating appropriate behavioral responses in the face of competing signals that predict either rewards or threats in the environment is crucial for survival. The basolateral nucleus of the amygdala (BLA) and prelimbic (PL) medial prefrontal cortex have been implicated in reward-seeking and fear-related responses, but how information flows between these reciprocally connected structures to coordinate behavior is unknown. We recorded neuronal activity from the BLA and PL while rats performed a task wherein competing shock- and sucrose-predictive cues were simultaneously presented. The correlated firing primarily displayed a BLA→PL directionality during the shock-associated cue. Furthermore, BLA neurons optogenetically identified as projecting to PL more accurately predicted behavioral responses during competition than unidentified BLA neurons. Finally photostimulation of the BLA→PL projection increased freezing, whereas both chemogenetic and optogenetic inhibition reduced freezing. Therefore, the BLA→PL circuit is critical in governing the selection of behavioral responses in the face of competing signals.National Institutes of Health (U.S.) (Award 1R25-MH092912-01)National Institute of Mental Health (U.S.) (Grant R01- MH102441-01)National Institutes of Health (U.S.) (Award DP2- DK-102256-01

Astroglial-Kir4.1 in Lateral Habenula Drives Neuronal Bursts to Mediate Depression

International audienceEnhanced bursting activity of neurons in the lateral habenula (LHb) is essential in driving depression-like behaviours, but the cause of this increase has been unknown. Here, using a high-throughput quantitative proteomic screen, we show that an astroglial potassium channel (Kir4.1) is upregulated in the LHb in rat models of depression. Kir4.1 in the LHb shows a distinct pattern of expression on astrocytic membrane processes that wrap tightly around the neuronal soma. Electrophysiology and modelling data show that the level of Kir4.1 on astrocytes tightly regulates the degree of membrane hyperpolarization and the amount of bursting activity of LHb neurons. Astrocyte-specific gain and loss of Kir4.1 in the LHb bidirectionally regulates neuronal bursting and depression-like symptoms. Together, these results show that a glia–neuron interaction at the perisomatic space of LHb is involved in setting the neuronal firing mode in models of a major psychiatric disease. Kir4.1 in the LHb might have potential as a target for treating clinical depression

The evolution of the upright posture and gait—a review and a new synthesis

During the last century, approximately 30 hypotheses have been constructed to explain the evolution of the human upright posture and locomotion. The most important and recent ones are discussed here. Meanwhile, it has been established that all main hypotheses published until the last decade of the past century are outdated, at least with respect to some of their main ideas: Firstly, they were focused on only one cause for the evolution of bipedality, whereas the evolutionary process was much more complex. Secondly, they were all placed into a savannah scenario. During the 1990s, the fossil record allowed the reconstruction of emerging bipedalism more precisely in a forested habitat (e.g., as reported by Clarke and Tobias (Science 269:521–524, 1995) and WoldeGabriel et al. (Nature 412:175–178, 2001)). Moreover, the fossil remains revealed increasing evidence that this part of human evolution took place in a more humid environment than previously assumed. The Amphibian Generalist Theory, presented first in the year 2000, suggests that bipedalism began in a wooded habitat. The forests were not far from a shore, where our early ancestor, along with its arboreal habits, walked and waded in shallow water finding rich food with little investment. In contrast to all other theories, wading behaviour not only triggers an upright posture, but also forces the individual to maintain this position and to walk bipedally. So far, this is the only scenario suitable to overcome the considerable anatomical and functional threshold from quadrupedalism to bipedalism. This is consistent with paleoanthropological findings and with functional anatomy as well as with energetic calculations, and not least, with evolutionary psychology. The new synthesis presented here is able to harmonise many of the hitherto competing theories

Los niños y niñas como constructores de conocimiento: un caso de investigación participativa

La investigación participativa con niños y niñas compone el objeto de análisis de este trabajo. Definiendo el conocimiento como una herramienta de transformación de la realidad, se avanza con un recorrido por diversas matrices teóricas de niñez, dando cuenta del proceso de invisibilización sufrido por niños y niñas en tanto sujetos de su propia historia, capaces de comprender su realidad y reflexionar sobre ella. En este punto propongo los enfoques co-participativos para recuperar las voces de los niños y niñas que han sido históricamente silenciadas. Esta hipótesis se pone en práctica en una experiencia llamada Aula Vereda, un espacio barrial de educación popular con niños y niñas de un barrio de la Ciudad de Buenos Aires, donde se desarrolla una Investigación Participativa.-1.Presentación.-2. Reflexión Metodológica.-3.Investigar para democratizar.-4.Niñez desigual, niñez ciudadana. -5. AulaVereda: una puesta en práctica. -6. Una propuesta que no concluye. -Lista de referencias

Mathematics in Kant\u27s critical philosophy: Reflections on mathematical practice

Many recent attempts to analyze Kant\u27s philosophy of mathematics have proceeded from within the contextual confines of Kant\u27s own Critique of Pure Reason. I aim to give a new reading of some of Kant\u27s most important claims about mathematical cognition by examining them within the context of the eighteenth century mathematical practice with which he was engaged. First, I investigate Euclid\u27s reasoning in the Elements and show that the Euclidean diagram serves a valid demonstrative role in the proofs of Euclidean propositions. I thereby re-evaluate the axiomatic nature of Euclid\u27s enterprise, and counter modern objections to Euclid\u27s reasoning made on the basis of subsequently developed standards of proof. Second, I assess the state of early modern elementary mathematics by using Christian Wolff\u27s Elementa Matheseos Universae as a tool for revealing how Wolff and his contemporaries reformulated the elements of pure mathematics. In particular, I analyze the method of constructing equations and conclude that algebra was not conceived as an independent discipline with its own object of investigation, but rather was a method of reasoning about the constructible objects of arithmetic and geometry. Finally, I provide a new reading of Kant\u27s critical claims about mathematics. A familiar geometric demonstration is used to clarify Kant\u27s distinction between pure and empirical intuition and to locate the source of the synthetic a priority of mathematical judgments; the schematism of mathematical concepts is shown both to provide the rules that we follow for the construction of those concepts and to confer universality on our mathematical judgments; and Kant\u27s theory of algebraic cognition is re-interpreted in order to demonstrate that for Kant all construction is ostensive