bluuebunny/crossref_metadata_2025 huggingface dataset:
Learning Acts on Distinct Processes for Visual Form Perception in the Human Brain
Authors: Mayhew Stephen D. , Li Sheng , Kourtzi Zoe
Published: January 2012

Learning is known to facilitate our ability to detect targets in clutter and optimize brain processes for successful visual recognition. Previous brain-imaging studies have focused on identifying spatial patterns (i.e., brain areas) that change with learning, implicating occipitotemporal and frontoparietal areas. However, little is known about the interactions within this network that mediate learning-dependent improvement in complex perceptual tasks (i.e., discrimination of visual forms in clutter). Here we take advantage of the complementary high spatial and temporal resolution of simultaneous EEG-fMRI to identify the learning-dependent changes in spatiotemporal brain patterns that mediate enhanced behavioral sensitivity in the discrimination of global forms after training. We measured the observers' choices when discriminating between concentric and radial patterns presented in noise before and after training. Similarly, we measured the choices of a pattern classifier when predicting each stimulus from EEG-fMRI signals. By comparing the performance of human observers and classifiers, we demonstrated that learning alters sensitivity to visual forms and EEG-fMRI activation patterns related to distinct visual recognition processes. In particular, behavioral improvement after training was associated with changes in (1) early processes involved in the integration of global forms in higher occipitotemporal and parietal areas, and (2) later processes related to categorical judgments in frontal circuits. Thus, our findings provide evidence that learning acts on distinct visual recognition processes and shapes feedforward interactions across brain areas to support performance in complex perceptual tasks.
GDNF Is Predominantly Expressed in the PV+ Neostriatal Interneuronal Ensemble in Normal Mouse and after Injury of the Nigrostriatal Pathway
Authors: Hidalgo-Figueroa María , Bonilla Sonia , Gutiérrez Francisco , Pascual Alberto , López-Barneo José
Published: January 2012

Glial cell line-derived neurotrophic factor (GDNF) is absolutely required for survival of dopaminergic (DA) nigrostriatal neurons and protect them from toxic insults. Hence, it is a promising, albeit experimental, therapy for Parkinson's disease (PD). However, the source of striatal GDNF is not well known. GDNF seems to be normally synthesized in neurons, but numerous reports suggest GDNF production in glial cells, particularly in the injured brain. We have studied in detail striatal GDNF production in normal mouse and after damage of DA neurons with MPTP. StriatalGDNFmRNA was present in neonates but markedly increased during the first 2–3 postnatal weeks. Cellular identification of GDNF by unequivocal histochemical methods demonstrated that in normal or injured adult animals GDNF is expressed by striatal neurons and is not synthesized in significant amounts by astrocytes or microglial cells.GDNFmRNA expression was not higher in reactive astrocytes than in normal ones. Approximately 95% of identified neostriatal GDNF-expressing cells in normal and injured animals are parvalbumin-positive (PV+) interneurons, which only represent ∼0.7% of all striatal neurons. The remaining 5% of GDNF+ cells are cholinergic and somatostatin+ interneurons. Surprisingly, medium spiny projection neurons (MSNs), the vast majority of striatal neurons that receive a strong DA innervation, do not express GDNF. PV+ interneurons constitute an oscillatory functional ensemble of electrically connected cells that control MSNs' firing. Production of GDNF in the PV+ neurons might be advantageous to supply synchronous activity-dependent release of GDNF in broad areas of the striatum. Stimulation of the GDNF-producing striatal PV+ ensemble in PD patients could have therapeutic effects.
Command and Compensation in a Neuromodulatory Decision Network
Authors: Luan Haojiang , Diao Fengqiu , Peabody Nathan C. , White Benjamin H.
Published: January 2012

The neural circuits that mediate behavioral choices must not only weigh internal demands and environmental circumstances, but also select and implement specific actions, including associated visceral or neuroendocrine functions. Coordinating these multiple processes suggests considerable complexity. As a consequence, even circuits that support simple behavioral decisions remain poorly understood. Here we show that the environmentally sensitive wing expansion decision of adult fruit flies is coordinated by a single pair of neuromodulatory neurons with command-like function. Targeted suppression of these neurons using the Split Gal4 system abrogates the fly's ability to expand its wings in the face of environmental challenges, while stimulating them forces expansion by coordinately activating both motor and neuroendocrine outputs. The arbitration and implementation of the wing expansion decision by this neuronal pair may illustrate a general strategy by which neuromodulatory neurons orchestrate behavior. Interestingly, the decision network exhibits a plasticity that is unmasked under conducive environmental conditions in flies lacking the function of the command-like neuromodulatory neurons. Such flies can often expand their wings using a motor program distinct from that of wild-type animals and controls. This compensatory program may be the vestige of an ancestral, environmentally insensitive program used for wing expansion that existed before the evolution of the environmentally adaptive program currently used byDrosophilaand other cyclorrhaphan flies.
Recurrent Neural Processing and Somatosensory Awareness
Authors: Auksztulewicz Ryszard , Spitzer Bernhard , Blankenburg Felix
Published: January 2012

The neural mechanisms of stimulus detection, despite extensive research, remain elusive. The recurrent processing hypothesis, a prominent theoretical account of perceptual awareness, states that, although stimuli might in principle evoke feedforward activity propagating through the visual cortex, stimuli that become consciously detected are further processed in feedforward–feedback loops established between cortical areas. To test this theory in the tactile modality, we applied dynamic causal modeling to electroencephalography (EEG) data acquired from humans in a somatosensory detection task. In the analysis of stimulation-induced event-related potentials (ERPs), we focused on model-based evidence for feedforward, feedback, and recurrent processing between primary and secondary somatosensory cortices. Bayesian model comparison revealed that, although early EEG components were well explained by both the feedforward and the recurrent models, the recurrent model outperformed the other models when later EEG segments were analyzed. Within the recurrent model, stimulus detection was characterized by a relatively early strength increase of the feedforward connection from primary to secondary somatosensory cortex (>80 ms). At longer latencies (>140 ms), also the feedback connection showed a detection-related strength increase. The modeling results on relative evidence between recurrent and feedforward model comparison support the hypothesis that the ERP responses from sensory areas arising after aware stimulus detection can be explained by increased recurrent processing within the somatosensory network in the later stages of stimulus processing.
HumanROBO1Regulates Interaural Interaction in Auditory Pathways
Authors: Lamminmäki Satu , Massinen Satu , Nopola-Hemmi Jaana , Kere Juha , Hari Riitta
Published: January 2012

In rodents, theRobo1gene regulates midline crossing of major nerve tracts, a fundamental property of the mammalian CNS. However, the neurodevelopmental function of the humanROBO1gene remains unknown, apart from a suggested role in dyslexia. We therefore studied axonal crossing with a functional approach, based on magnetoencephalography, in 10 dyslexic individuals who all share the same rare, weakly expressing haplotype of theROBO1gene. Auditory-cortex responses were recorded separately to left- and right-ear sounds that were amplitude modulated at different frequencies. We found impaired interaural interaction that depended on theROBO1in a dose-dependent manner. Our results indicate that normal crossing of the auditory pathways requires an adequateROBO1expression level.
Attentional Capture? Synchronized Feedback Signals from the Isthmi Boost Retinal Signals to Higher Visual Areas
Authors: Marín Gonzalo J. , Durán Ernesto , Morales Cristian , González-Cabrera Cristian , Sentis Elisa , Mpodozis Jorge , Letelier Juan Carlos
Published: January 2012

When a salient object in the visual field captures attention, the neural representation of that object is enhanced at the expense of competing stimuli. How neural activity evoked by a salient stimulus evolves to take precedence over the neural activity evoked by other stimuli is a matter of intensive investigation. Here, we describe in pigeons (Columba livia) how retinal inputs to the optic tectum (TeO, superior colliculus in mammals), triggered by moving stimuli, are selectively relayed on to the rotundus (Rt, caudal pulvinar) in the thalamus, and to its pallial target, the entopallium (E, extrastriate cortex). We show that two satellite nuclei of the TeO, the nucleus isthmi parvocelullaris (Ipc) and isthmi semilunaris (SLu), send synchronized feedback signals across tectal layers. Preventing the feedback from Ipc but not from SLu to a tectal location suppresses visual responses to moving stimuli from the corresponding region of visual space in all Rt subdivisions. In addition, the bursting feedback from the Ipc imprints a bursting rhythm on the visual signals, such that the visual responses of the Rt and the E acquire a bursting modulation significantly synchronized to the feedback from Ipc. As the Ipc feedback signals are selected by competitive interactions, the visual responses within the receptive fields in the Rt tend to synchronize with the tectal location receiving the “winning” feedback from Ipc. We propose that this selective transmission of afferent activity combined with the cross-regional synchronization of the areas involved represents a bottom-up mechanism by which salient stimuli capture attention.
Dissociating the Role of Prefrontal and Premotor Cortices in Controlling Inhibitory Mechanisms during Motor Preparation
Authors: Duque Julie , Labruna Ludovica , Verset Sophie , Olivier Etienne , Ivry Richard B.
Published: January 2012

Top-down control processes are critical to select goal-directed actions in flexible environments. In humans, these processes include two inhibitory mechanisms that operate during response selection: one is involved in solving a competition between different response options, the other ensures that a selected response is initiated in a timely manner. Here, we evaluated the role of dorsal premotor cortex (PMd) and lateral prefrontal cortex (LPF) of healthy subjects in these two forms of inhibition by using an innovative transcranial magnetic stimulation (TMS) protocol combining repetitive TMS (rTMS) over PMd or LPF and a single pulse TMS (sTMS) over primary motor cortex (M1). sTMS over M1 allowed us to assess inhibitory changes in corticospinal excitability, while rTMS was used to produce transient disruption of PMd or LPF. We found that rTMS over LPF reduces inhibition associated with competition resolution, whereas rTMS over PMd decreases inhibition associated with response impulse control. These results emphasize the dissociable contributions of these two frontal regions to inhibitory control during motor preparation. The association of LPF with competition resolution is consistent with the role of this area in relatively abstract aspects of control related to goal maintenance, ensuring that the appropriate response is selected in a variable context. In contrast, the association of PMd with impulse control is consistent with the role of this area in more specific processes related to motor preparation and initiation.
Kisspeptin-GPR54 Signaling in Mouse NO-Synthesizing Neurons Participates in the Hypothalamic Control of Ovulation
Authors: Hanchate Naresh Kumar , Parkash Jyoti , Bellefontaine Nicole , Mazur Danièle , Colledge William H. , d'Anglemont de Tassigny Xavier , Prevot Vincent
Published: January 2012

Reproduction is controlled in the brain by a neural network that drives the secretion of gonadotropin-releasing hormone (GnRH). Various permissive homeostatic signals must be integrated to achieve ovulation in mammals. However, the neural events controlling the timely activation of GnRH neurons are not completely understood. Here we show that kisspeptin, a potent activator of GnRH neuronal activity, directly communicates with neurons that synthesize the gaseous transmitter nitric oxide (NO) in the preoptic region to coordinate the progression of the ovarian cycle. Using a transgenicGpr54-null IRES-LacZ knock-in mouse model, we demonstrate that neurons containing neuronal NO synthase (nNOS), which are morphologically associated with kisspeptin fibers, express the kisspeptin receptor GPR54 in the preoptic region, but not in the tuberal region of the hypothalamus. The activation of kisspeptin signaling in preoptic neurons promotes the activation of nNOS through its phosphorylation on serine 1412 via the AKT pathway and mimics the positive feedback effects of estrogens. Finally, we show that while NO release restrains the reproductive axis at stages of the ovarian cycle during which estrogens exert their inhibitory feedback, it is required for the kisspeptin-dependent preovulatory activation of GnRH neurons. Thus, interactions between kisspeptin and nNOS neurons may play a central role in regulating the hypothalamic–pituitary–gonadal axisin vivo.
Amygdala Central Nucleus Interacts with Dorsolateral Striatum to Regulate the Acquisition of Habits
Authors: Lingawi Nura W. , Balleine Bernard W.
Published: January 2012

The role of the amygdala central nucleus (CeN) in habit learning was assessed in two experiments. First, we examined the effects of bilateral lesions of the anterior CeN on an overtraining-induced lever press habit evaluated using an outcome devaluation protocol. Overtraining generated habitual performance and rendered sham lesioned rats insensitive to outcome devaluation, an effect that was also found in rats given control lesions of the posterior CeN. In contrast, rats with lesions of the anterior CeN did not show normal habit acquisition and their performance remained goal-directed and sensitive to outcome devaluation. Nevertheless, lesions of either the posterior or the anterior CeN abolished the general excitatory influence of a Pavlovian conditioned stimulus on instrumental performance. Second, we assessed the functional interaction between the CeN and dorsolateral striatum (DLS), a region previously implicated in the acquisition of habits, using asymmetrical lesions to disconnect these structures. Rats were given a unilateral lesion of anterior CeN and a unilateral lesion of the DLS, made either ipsilateral (control) or contralateral (disconnection) to the CeN lesion, and given overtraining followed by outcome devaluation. Although the ipsilateral lesioned rats were insensitive to devaluation, the contralateral CeN–DLS lesion impaired habit acquisition, rendering performance sensitive to the devaluation treatment. These results are the first to implicate the CeN and its connection with a circuit involving DLS in habit learning. They imply that, in instrumental conditioning, regions of amygdala parse the instrumental outcome into the reward and reinforcement signals mediating goal-directed and habitual actions, respectively.
Gating of Sensory Input at Spinal and Cortical Levels during Preparation and Execution of Voluntary Movement
Authors: Seki Kazuhiko , Fetz Eberhard E.
Published: January 2012

All bodily movements stimulate peripheral receptors that activate neurons in the brain and spinal cord through afferent feedback. How these reafferent signals are processed within the CNS during movement is a key question in motor control. We investigated cutaneous sensory-evoked potentials in the spinal cord, primary somatosensory and motor cortex, and premotor cortex in monkeys performing an instructed delay task. Afferent inputs from cutaneous receptors were suppressed at several levels in a task-dependent manner. We found two types of suppression. First, suppression during active limb movement was observed in the spinal cord and all three cortical areas. This suppression was induced by both bottom-up and top-down gating mechanisms. Second, during preparation for upcoming movement, evoked responses were suppressed exclusively in the motor cortical areas and the magnitude of suppression was correlated with the reaction time of the subsequent movement. This suppression could be induced by a top-down gating mechanism to facilitate the preparation and execution of upcoming movement.
Short-Term Plasticity of Unitary Inhibitory-to-Inhibitory Synapses Depends on the Presynaptic Interneuron Subtype
Authors: Ma Yunyong , Hu Hang , Agmon Ariel
Published: January 2012

Excitatory-to-inhibitory cortical synapses exhibit either short-term facilitation or depression, depending on the subtype identity of the postsynaptic interneuron, while the short-term plasticity (STP) of inhibitory-to-excitatory synapses depends on the presynaptic interneuron. However, the rules governing STP of inhibitory-to-inhibitory synapses have not yet been determined. We recorded 109 unitary connections made by the two major inhibitory interneuron subtypes in layer 4 of mouse somatosensory cortex, fast-spiking (FS) and somatostatin-containing (SOM) interneurons, on each other and on excitatory, regular-spiking (RS) neurons. In all pairs, we measured dynamic changes in the postsynaptic response to a 20 Hz train of presynaptic action potentials. In half of our dataset, we also measured kinetic properties of the unitary IPSC: latency, rise time, and decay time constant. We found a pronounced dependency of STP on the presynaptic, but not the postsynaptic, identity: FS interneurons made strongly depressing connections on FS, SOM, and RS targets, while in synapses made by SOM interneurons on FS and RS targets, weak early depression was followed by weak late facilitation. IPSC latency and rise time were also strongly dependent on the presynaptic interneuron subtype, being 1.5–2× slower in output synapses of SOM compared with FS interneurons. In contrast, the IPSC decay time constant depended only on the postsynaptic class, with 1.5× slower decay on excitatory compared with inhibitory targets. The properties of the inhibitory outputs of FS and SOM interneurons reciprocate the properties of their excitatory inputs and imply a dynamic spatiotemporal division of labor between these two major inhibitory subsystems.
Neural Representations of Courtship Song in theDrosophilaBrain
Authors: Tootoonian Sina , Coen Philip , Kawai Risa , Murthy Mala
Published: January 2012

Acoustic communication in drosophilid flies is based on the production and perception of courtship songs, which facilitate mating. Despite decades of research on courtship songs and behavior inDrosophila, central auditory responses have remained uncharacterized. In this study, we report on intracellular recordings from central neurons that innervate theDrosophilaantennal mechanosensory and motor center (AMMC), the first relay for auditory information in the fly brain. These neurons produce graded-potential (nonspiking) responses to sound; we compare recordings from AMMC neurons to extracellular recordings of the receptor neuron population [Johnston's organ neurons (JONs)]. We discover that, while steady-state response profiles for tonal and broadband stimuli are significantly transformed between the JON population in the antenna and AMMC neurons in the brain, transient responses to pulses present in natural stimuli (courtship song) are not. For pulse stimuli in particular, AMMC neurons simply low-pass filter the receptor population response, thus preserving low-frequency temporal features (such as the spacing of song pulses) for analysis by postsynaptic neurons. We also compare responses in two closely relatedDrosophilaspecies,Drosophila melanogasterandDrosophila simulans, and find that pulse song responses are largely similar, despite differences in the spectral content of their songs. Our recordings inform how downstream circuits may read out behaviorally relevant information from central neurons in the AMMC.
Cellular Mechanisms Underlying Spatiotemporal Features of Cholinergic Retinal Waves
Authors: Ford Kevin J. , Félix Aude L. , Feller Marla B.
Published: January 2012

Before vision, a transient network of recurrently connected cholinergic interneurons, called starburst amacrine cells (SACs), generates spontaneous retinal waves. Despite an absence of robust inhibition, cholinergic retinal waves initiate infrequently and propagate within finite boundaries. Here, we combine a variety of electrophysiological and imaging techniques and computational modeling to elucidate the mechanisms underlying these spatial and temporal properties of waves in developing mouse retina. Waves initiate via rare spontaneous depolarizations of SACs. Waves propagate through recurrent cholinergic connections between SACs and volume release of ACh as demonstrated using paired recordings and a cell-based ACh optical sensor. Perforated-patch recordings and two-photon calcium imaging reveal that individual SACs have slow afterhyperpolarizations that induce SACs to have variable depolarizations during sequential waves. Using a computational model in which the properties of SACs are based on these physiological measurements, we reproduce the slow frequency, speed, and finite size of recorded waves. This study represents a detailed description of the circuit that mediates cholinergic retinal waves and indicates that variability of the interneurons that generate this network activity may be critical for the robustness of waves across different species and stages of development.
Reduced Activity of AMP-Activated Protein Kinase Protects against Genetic Models of Motor Neuron Disease
Authors: Lim M. A. , Selak M. A. , Xiang Z. , Krainc D. , Neve R. L. , Kraemer B. C. , Watts J. L. , Kalb R. G.
Published: January 2012

A growing body of research indicates that amyotrophic lateral sclerosis (ALS) patients and mouse models of ALS exhibit metabolic dysfunction. A subpopulation of ALS patients possesses higher levels of resting energy expenditure and lower fat-free mass compared to healthy controls. Similarly, two mutant copper zinc superoxide dismutase 1 (mSOD1) mouse models of familial ALS possess a hypermetabolic phenotype. The pathophysiological relevance of the bioenergetic defects observed in ALS remains largely elusive. AMP-activated protein kinase (AMPK) is a key sensor of cellular energy status and thus might be activated in various models of ALS. Here, we report that AMPK activity is increased in spinal cord cultures expressing mSOD1, as well as in spinal cord lysates from mSOD1 mice. Reducing AMPK activity either pharmacologically or genetically prevents mSOD1-induced motor neuron deathin vitro. To investigate the role of AMPKin vivo, we usedCaenorhabditis elegansmodels of motor neuron disease.C. elegansengineered to express human mSOD1 (G85R) in neurons develops locomotor dysfunction and severe fecundity defects when compared to transgenic worms expressing human wild-type SOD1. Genetic reduction ofaak-2, the ortholog of the AMPK α2 catalytic subunit in nematodes, improved locomotor behavior and fecundity inG85Ranimals. Similar observations were made with nematodes engineered to express mutant tat-activating regulatory (TAR) DNA-binding protein of 43 kDa molecular weight. Altogether, these data suggest that bioenergetic abnormalities are likely to be pathophysiologically relevant to motor neuron disease.
Eine neue Form von Cavity Enhanced Absorption Spectroscopy
Authors: Petermann Christian , Fischer Peer
Published: January 2012

Wir stellen eine Kopplungsmethode für resonatorgestützte Absorptionsmessungen vor, bei der Licht durch einen im Resonator platzierten akustooptischen Modulator aktiv ein- und ausgekoppelt wird. Dies ermöglicht es Cavity-Ring-Down-Spektroskopie (CRDS) mit breitbandigen und zeitlich inkohärenten Lichtquellen niedriger spektraler Leistungsdichte durchzuführen. Das Verfahren wird zum ersten Mal mit einer breitbandigen Superkontinuum-Quelle demonstriert.
Sensitive and Fast Gas Sensor for Wide Variety of Applications Based on Novel Differential Infrared Photoacoustic Principle
Authors: Kauppinen Ismo , Branders Arto , Uotila Juho , Sinisalo Sauli , Kauppinen Jyrki , Kuusela Tom
Published: January 2012

A modular sensor concept for various gas measurement applications requiring high sensitivity and fast response time is presented. The proposed differential photoacoustic detection combines the selectivity of the traditional absorption method and the high sensitivity of the novel cantilever enhanced photoacoustic detector. High precision is achieved using short optical path length resulting in fast response time and wide dynamic measurement range. An example realization for greenhouse gas flux measurement is presented.
Systemintegration von Sensoren für fluoreszenzbasierte Lab-on-a-Chip Systeme
Authors: Witte Andreas , Schmitt Robert
Published: January 2012

Lab-on-a-Chip Systeme sind wesentlicher Bestandteil der aktuellen Forschung und werden vermehrt auch im Bereich der klinischen Krankheitsdiagnose eingesetzt. Die Systemintegration von Sensoren zur Analyse von Proben stellt eine besondere Herausforderung an den Designprozess und die Entwicklung aller Systemkomponenten dar. In diesem Beitrag werden diese Anforderungen zusammengefasst und das entwickelte Analysesystem gezeigt.
SensMiLi: Absolutes Wegmess-System aus einer diffraktiven q-nären Pseudo-Zufalls-Sequenz
Authors: Wibbing Daniel , Binder Josef , Schinköthe Wolfgang , Pauly Christoph , Gachot Carsten , Mücklich Frank
Published: January 2012

Es wird ein neuartiges Prinzip für ein optisch absolut codiertes Wegmess-System vorgestellt, das auf der Beugung von Licht beruht. Optimiert für die Integration in Miniatur-Linearmotoren soll es diese zu hochdynamischen, mikrometergenauen Bewegungen in Reinräumen befähigen. Zum ersten Mal wird gezeigt wie q-näre Pseudo-Zufalls-Sequenzen durch optische Beugung codiert werden können und so u. a. Verbesserungen bzgl. Code-Effizienz, Integrationsfähigkeit und Robustheit ermöglichen.
Miniaturisierte Infrarot-Spektrometer zur Ölzustandsüberwachung in Offshore-Windkraftgetrieben
Authors: Wiesent Benjamin R. , Dorigo Daniel G. , Şimşek Özlem , Koch Alexander W.
Published: January 2012

Infrarot-basierte Ölzustandssensoren liefern wertvolle Informationen über den Zustand von Getrieben und ermöglichen somit die langfristige Planung von Wartungsarbeiten. Derzeit verfügbare Systeme basieren meist auf nicht-dispersiven Verfahren und liefern lediglich Information über einen einzelnen Ölalterungsparameter. Zudem sind sie oftmals nur auf einen Öltyp angepasst. Miniaturisierte Infrarotspektrometer bieten die Möglichkeit, viele relevante Ölalterungsparameter simultan zu erfassen, und sind dabei gleichzeitig auf einen großen Kreis von Öltypen anwendbar. In diesem Beitrag präsentieren wir eine Methode zur Wahl eines geeigneten Spektralapparates auf Basis einer Multivariaten Kalibration. Dabei zeigen und diskutieren wir Einschränkungen der jeweiligen Spektralapparate im Hinblick auf spektrale Bandbreite, Auflösung und SNR auf die Güte der spektralen Datenauswertung. Im weiteren werden die Realisierung und Messergebnisse eines miniaturisierten Infrarotspektrometers auf Basis eines Linear Variablen Filters (LVF) zur Getriebeölüberwachung von Offshore-Windkraftgetrieben vorgestellt.
Magic Mirrors: Formalist Realism in Victorian Physics and Photography
Authors: Henderson Andrea
Published: January 2012

This essay argues that British photography of the 1850s and ’60s wedded realism—understood as a commitment to descriptive truthfulness—with formalism, or a belief in the defining power of structural relationships. Photographers at midcentury understood the realistic character of photography to be grounded in more than fidelity to detail; the technical properties of the medium accorded perfectly with the claims of contemporary physicists that reality itself was constituted by spatial arrangements and polar forces rather than essential categorical distinctions. The photographs of Clementina, Lady Hawarden exemplify this formalist realism, dramatizing the power of the formal logic of photography not only to represent the real but to reveal its fundamentally formal nature.
Deadly Dialogue: Thucydides with Plato
Authors: Boyarin Daniel
Published: January 2012

In this paper it will be argued that Thucydides's Melian Dialogue is best illuminated in the context of Socratic dialogue as given by Plato. Thucydides and Plato take directly oppositional positions on dialogue versus debate or philosophy versus rhetoric.
Arranjo de plantas na expressão dos componentes da produtividade de grãos de canola
Authors: Krüger Cleusa Adriane Menegassi Bianchi , Silva José Antonio Gonzalez da , Medeiros Sandro Luis Petter , Dalmago Genei Antonio , Sartori César Oneide , Schiavo Jordana
Published: January 2012

O objetivo deste trabalho foi avaliar os efeitos do arranjo de plantas nos componentes diretos da produtividade de grãos e na produção final em canola, com uso de híbridos de diferentes ciclos de desenvolvimento. Foram realizados três experimentos com espaçamento entre linhas de 0,20, 0,40 e 0,60 m, em delineamento experimental de blocos ao acaso, com quatro repetições para cada ano de cultivo (2008 e 2009), genótipo (Hyola 432 e Hyola 61) e densidade de plantas (20, 40, 60 e 80 plantas por metro quadrado). Hyola 432 apresentou maior produção de grãos em comparação a Hyola 61, independentemente do ano e da densidade de cultivo. Os efeitos do ano de cultivo influenciaram mais a produção e os componentes da produtividade de grãos do que o potencial genético da cultivar e a densidade de cultivo. O ajuste da densidade de plantas em canola é alterado pelo genótipo e pelo ano de cultivo.
Desempenho agronômico de genótipos de capim-braquiária em sucessão à soja
Authors: Machado Luís Armando Zago , Valle Cacilda Borges do
Published: January 2012

O objetivo deste trabalho foi avaliar o desempenho agronômico de genótipos de capim-braquiária [Urochloa brizantha (Syn. Brachiaria brizantha)] em sucessão à soja, para uso em sistemas de integração lavoura-pecuária. Os genótipos Marandu, MG 4, Xaraés, Piatã, Arapoty e B 6, foram avaliados na safrinha, durante a estação seca, e a soja na safra de verão, em esquema de sucessão, de 2007 a 2010. Em cada ano, as forrageiras foram semeadas em março, avaliadas em cortes sucessivos até o final de setembro e dessecadas em outubro para a realização do plantio direto da soja em novembro. Utilizou-se o delineamento de blocos ao acaso, com quatro repetições. Xaraés e B 6 estiveram entre os genótipos com maior produção de forragem. A cultivar Xaraés apresentou menores teores de proteína bruta, digestibilidade in vitro da matéria orgânica, cálcio e fósforo, embora esses teores possam ser considerados bons para o gênero, uma vez que o solo de cultivo apresentava boa fertilidade. Há variação entre os genótipos de U. brizantha quanto ao desempenho na safrinha. A cultivar Xaraés e o genótipo B 6 destacam-se para compor sistemas de produção integrados com lavoura. Os genótipos MG 4 e B6 são facilmente dessecados com o herbicida glifosato. A produtividade de grãos de soja não é significativamente afetada pelo cultivo em sucessão aos genótipos de U. brizantha.
Atividade proteolítica e crescimento de matrinxã em natação sustentada e alimentado com dois níveis de proteína
Authors: Arbeláez-Rojas Gustavo Alberto , Inoue Luís Antônio Kioshi Aoki , Moraes Gilberto
Published: January 2012

O objetivo deste trabalho foi avaliar o efeito da natação sustentada sobre a atividade digestiva proteolítica e o crescimento de juvenis de matrinxã (Brycon amazonicus), alimentados com dois níveis de proteína. Foram utilizados 240 peixes, tratados com 28 ou 38% de proteína bruta (PB), durante 60 dias, em duas situações distintas: em natação sustentada à velocidade de uma vez e meia o comprimento corporal por segundo, e em sistema convencional de cultivo, sem movimento forçado. Os peixes em natação sustentada e alimentados com 28% de PB apresentaram melhor desempenho, expresso como maior crescimento, alta taxa de crescimento específico, maior ganho de peso e melhor eficiência alimentar. A natação sustentada proporcionou aumento significativo da atividade digestiva proteolítica alcalina, proporcional ao conteúdo de proteína na dieta. Juvenis de matrinxã alimentados com dietas com 28% de PB e em natação sustentada apresentam melhor aproveitamento dos nutrientes como consequência de ação proteolítica digestiva mais efetiva.
Imagens mono e multitemporais Modis para estimativa da área com soja no estado de Mato Grosso
Authors: Bernardes Tiago , Adami Marcos , Formaggio Antônio Roberto , Moreira Maurício Alves , França Daniela de Azeredo , Novaes Maikon Roberth de
Published: January 2012

O objetivo deste trabalho foi avaliar uma nova metodologia para mapeamento da cultura da soja no Estado de Mato Grosso, por meio de imagens Modis e de diferentes abordagens de classificação de imagens. Foram utilizadas imagens diárias e imagens de 16 dias. As imagens diárias foram diretamente classificadas pelo algoritmo Isoseg. As duas séries de imagens de 16 dias, referentes ao ciclo total e à metade do ciclo da cultura da soja, foram transformadas pela análise de componentes principais (ACP), antes de serem classificadas. Dados de referência, obtidos por interpretação visual de imagens do sensor TM/Landsat-5, foram utilizados para a avaliação da exatidão das classificações. Os melhores resultados foram obtidos pela classificação das imagens do ciclo total da soja, transformadas pela ACP: índice global de 0,83 e Kappa de 0,63. A melhor classificação de imagens diárias mostrou índice global de 0,80 e Kappa de 0,55. AACP aplicada às imagens do ciclo total da soja permitiu o mapeamento das áreas de soja com índices de exatidão melhores do que os obtidos pela classificação derivada das imagens de data única.
Atividade microbiana e enzimática em solo após a aplicação de xisto retortado
Authors: Doumer Marta Eliane , Giacomini Sandro José , Silveira Carlos Augusto Posser , Weiler Douglas Adams , Bastos Leonardo Mendes , Freitas Luana Liberalesso de
Published: January 2012

O objetivo deste trabalho foi avaliar o efeito da aplicação de doses crescentes de xisto retortado (XR) sobre características biológicas indicadoras da qualidade do solo. Foram realizados experimentos, em Argissolo Vermelho distrófico arênico, em condições de laboratório e de campo. Em laboratório, os tratamentos consistiram da aplicação ao solo de sete diferentes doses de XR (0, 300, 450, 600, 750, 1.500 e 3.000 kg ha-1). Em campo, os tratamentos foram compostos por quatro diferentes doses de XR (0, 750, 1.500, 3.000 kg ha-1) combinadas à adubação mineral recomendada, avaliados em dois cultivos de feijão (Phaseolus vulgaris L.), no sistema plantio direto. Avaliaram-se: a evolução de CO2, o carbono da biomassa microbiana (CBM), a atividade enzimática do solo e o teste de ecotoxicidade. A aplicação de doses crescentes de XR melhorou a atividade microbiológica do solo, por reduzir a emissão de CO2 sem causar variação no CBM e sem provocar impactos negativos sobre a atividade enzimática do solo. Os resultados obtidos com as enzimas em condições de campo, após duas aplicações de XR, aliados aos de CBM, do quociente metabólico (qCO2) e do teste ecotoxicológico, em condições de laboratório, indicam que o uso do XR não provoca a degradação biológica do solo.
Changes in the isoflavone profile and in the chemical composition of tempeh during processing and refrigeration
Authors: Ferreira Márcia Pires , Oliveira Maria Cristina Neves de , Mandarino José Marcos Gontijo , Silva Josemeyre Bonifácio da , Ida Elza Iouko , Carrão-Panizzi Mercedes Concórdia
Published: January 2012

The objective of this work was to analyze changes in the isoflavone profile, determined by high performance liquid chromatography, at different processing stages and after refrigeration of tempeh. For tempeh production, clean soybean grains from cultivars BR 36 (low isoflavone content) and IAS 5 (high) were dehulled, and the separated cotyledons were hydrated and then cooked in boiling water for 30 min. Spores of the fungus Rhizopus microsporus var. oligosporus were inoculated in the cooked and cooled cotyledons, and incubated at 32ºC for 6, 12, 18, and 24 hours in perforated polypropylene bags, for fermentation. The resulting tempeh was stored at 4ºC for 6, 12, 18, and 24 hours. After 24-hour fermentation, isoflavone glucosides were 50% reduced, and the aglycone forms in the tempeh from both cultivars was increased. The malonyl forms reduced 83% after cooking. Less than 24 hours of refrigeration did not affect the isoflavone profile of tempeh from either cultivar, which is a good indicator of its quality. The tempeh maintains the high and low isoflavone content of the cultivars, which indicates that cultivar differences in this trait should be considered when processing tempeh.
A chamada "nova classe média": cultura material, inclusão e distinção social
Authors: Yaccoub Hilaine
Published: January 2012

O presente artigo tem como objetivo apresentar uma discussão sobre a importância do consumo e cultura material para um determinado estrato social. A partir de uma pesquisa realizada sobre ligações clandestinas de energia elétrica, fenômeno sociotécnico de dimensões culturais conhecido por "gatos", residi por oito meses em um bairro popular na região metropolitana do Rio de Janeiro. Como moradora, pude penetrar na vida do bairro e analisar o estilo de vida de um grupo de moradores considerado a elite local, que, àquela época, fazia parte de um contingente mais amplo da população brasileira que estava adquirindo visibilidade pública, sendo denominado pela mídia como "nova classe média". Devido ao aumento da renda, à política de juros baixos e aos financiamentos facilitados a partir do Plano Real, esses "novos consumidores" obtiveram mais acesso a bens duráveis, especialmente eletroeletrônicos, elevando assim seu status perante seus iguais e muitas vezes adequando através de táticas seu novo padrão de consumo. Por meio do consumo, principalmente de carros e eletroeletrônicos, eles almejam inclusão em outro estrato social, as camadas médias urbanas.
Campesinato e o Estado no Brasil
Authors: Seyferth Giralda
Published: January 2012

Neste trabalho, são discutidos alguns aspectos do debate conceitual que cerca as noções de campesinato e sociedade camponesa e as transformações sociais no campo, ressaltando o problema da relação dos camponeses com o Estado. A análise destaca um exemplo significativo dessa relação, a colonização estrangeira, resultante de políticas públicas voltadas para a ocupação de terras devolutas, iniciada no sul do Brasil em 1824. Trata-se de um caso que permite observar o papel do Estado no controle de um processo de povoamento envolvendo imigrantes europeus e a consequente formação de um tipo de campesinato étnico diferenciado de outras realidades rurais brasileiras.
Mineralogia e geoquímica da ocorrência de palygorskita de Alcântara, bacia de S. Luís-Grajaú, Maranhão
Authors: Amorim K. B. , Angélica R. S.
Published: January 2012

A Formação Alcântara (bacia de São Luis-Grajaú, região de Alcântara, MA) é constituída por pelitos, arenitos e dolomitos. Esses litotipos representam uma sucessão progradacional de depósitos de laguna/washover e canal de maré sobrepondo-se a depósitos de shoreface gerados por processos de tempestade. O presente trabalho tem como objetivo principal à caracterização mineralógica e geoquímica dos argilominerais que ocorrem nos níveis pelíticos da Formação Alcântara, especialmente a palygorskita. Foi descrito e amostrado um perfil geológico na praia da Baronesa, na cidade de Alcântara, MA, no qual foram coletadas 8 amostras, que após a preparação em laboratório, foram submetidas a análises mineralógicas e químicas por difração de raios X, fluorescência de raios X, análises térmicas e microscopia eletrônica de varredura. Os resultados mostraram que o perfil da praia da Baronesa é composto por arenitos na base, seguido de pelitos dominantes, com intercalações de dolomitos. Nos pelitos, foram descritos uma ampla assembléia de argilominerais, em ambiente lagunar, com variações no conteúdo de palygorskita, clorita, illita, esmectita e traços de caulinita. Observam-se ainda traços de dolomita, calcita e feldspatos. Os teores de palygorskita e dolomita (níveis dolomíticos) são acentuados, sugerindo que as condições climáticas durante o período de deposição foram áridas a semi-áridas. Duas gerações de palygorskita foram descritas: uma na forma de bolsões ou acumulações macroscópicas nos níveis pelíticos ricos em esmectita, freqüentemente descritas na literatura, e outra na forma maciça, como o mineral dominante dos níveis pelíticos superiores do perfil da praia da Baronesa. Essa segunda geração está sendo descrita pela primeira vez, neste trabalho, podendo constituir em níveis métricos e que podem revelar interesse econômico.
Chrysobrycon eliasi, new species of stevardiine fish (Characiformes: Characidae) from the río Madre de Dios and upper río Manuripe basins, Peru
Authors: Vanegas-Ríos James Anyelo , Azpelicueta María de las Mercedes , Ortega Hernán
Published: January 2012

Chrysobrycon eliasi is described from several drainages of río Madre de Dios and upper río Manuripe basins, río Madeira basin, Peru. The new species is distinguished from its congeners by the maxillary teeth, which are tricuspidate, bicuspidate and conical, and the terminal lateral-line tube developed between caudal-fin rays 10-11. Other characters that help to recognize C. eliasi are the possession of maxilla with 6-15 (usually 11) teeth occupying more than 70% of the length of the maxilla in adults, predorsal scales 18-22, dorsal-fin to hypural complex length 36.32-41.17% of standard length (SL), gill-gland length in males 3.57-5.05% SL, maxillary length 33.76-38.75% of head length, and branched anal-fin rays 24-30. The discovery of C. eliasi allows us to extend the geographic distribution of the genus to the southeast, into the río Madeira basin.
Ichthyoplankton of arvoredo biological marine reserve, Santa Catarina, Brazil
Authors: Rutkowski Thais , Schwingel Paulo Ricardo , Brilha Renan Todesco , Rodrigues-Ribeiro Marcelo
Published: January 2012

Arvoredo Island, located in Santa Catarina state - south Brazil, and its surrounding area were defined as a Conservation Unit (CU) in the category of Biological Reserve since 1990. This research aimed to analyze the inter-annual and seasonal (winter and summer) variations of ichthyoplankton densities at Arvoredo Biology Marine Reserve (ABMR), and their relationship with environmental variables in 1997/1998 (Campaign 1), 2007/2008 (Campaign 2) and 2008/2009 (Campaign 3). Fish eggs and larvae were sampled using a WP-2 net with 200 µm mesh size. The study area was influenced by three water masses, (i) Coastal Water throughout the whole year, (ii) Subtropical Shelf Water during the winter, and (iii) South Atlantic Central Water mainly in summer. A total of 4,891 eggs were collected and classified as Engraulidae and Sardinella brasiliensis (Clupeidae). The total number of larvae was 467 belonging to 5 orders, 19 families, and 21 species. Taxonomic composition demonstrated a seasonal pattern among periods, with the highest densities of Engraulidae occurring in winter and the families Carangidae, Clupeidae and Gerreidae in summer. The high number of families and abundance of ichthyoplankton observed in ABMR may be important in supplying the adjacent coastal areas impacted by fishing.
Mercury bioaccumulation in fish of commercial importance from different trophic categories in an Amazon floodplain lake
Authors: Beltran-Pedreros Sandra , Zuanon Jansen , Leite Rosseval Galdino , Peleja José Reinaldo Pacheco , Mendonça Alessandra Barros , Forsberg Bruce Rider
Published: January 2012

Thirty-two species of commercially important fish from three trophic levels and nine trophic categories were sampled at a floodplain lake of the Solimões River (Lago Grande de Manacapuru). The fish were analyzed to determine their Hg level and the bioaccumulation, bioconcentration, and biomagnification of this element. The observed increase in mean concentration of mercury (49.6 ng.g-1 for omnivores, 418.3 ng.g-1 for piscivores, and 527.8 ng.g-1 for carnivores/necrophages) furnished evidence of biomagnification. Primary, secondary, and tertiary consumers presented biomagnification factors of 0.27, 0.33, and 0.47, respectively. Significant differences in the bioconcentration and concentration of total Hg occurred between the categories of the third trophic level and the other categories. Plagioscion squamosissimus (carnivorous/piscivorous) and Calophysus macropterus (carnivorous/ necrophagous) showed levels of total Hg above those permitted by Brazilian law (500 ng.g-1). Six other species also posed risks to human health because their Hg levels exceeded 300 ng.g-1. Fifteen species showed bioaccumulation, but only eight presented significant correlations between the concentration of Hg and the length and/or the weight of the fish.
Uma crônica ignorada: Anselm Eckart e a Amazônia setecentista
Authors: Porro Antonio
Published: January 2012

Uma obra quase desconhecida do jesuíta alemão Anselm Eckart (1721-1809), os "Aditamentos à descrição das terras do Brasil", é de grande interesse para os estudos amazônicos. Eckart, que trabalhou de 1753 a 1757 nas missões do Maranhão e Grão-Pará, publicou suas próprias observações em apêndice à obra de outro autor sobre o mundo natural e a sociedade amazônica. Os capítulos dos "Aditamentos" que tratam da população indígena, de seus costumes e do tratamento recebido de colonos e missionários são aqui traduzidos por Thekla Hartmann e comentados pelo autor.
As notas do Padre Anselm Eckart, S. J., sobre alguns animais do Estado do Grão-Pará e Maranhão (1785)
Authors: Papavero Nelson , Couri Marcia Souto , Teixeira Dante Martins , Chiquieri Abner
Published: January 2012

Os trechos relativos à fauna do Estado do Grão-Pará e Maranhão, escritos pelo Padre Anselmo Eckart (1721-1807), S. J., em 1785, são traduzidos e comentados. Foram incluídas notas críticas sobre cada animal mencionado, atualizando o conhecimento sobre a espécie e comparando as informações zoológicas e linguísticas coligidas pelo jesuíta com outros documentos da época e com a literatura científica pertinente.
Obra de arte como território de existência
Authors: Thomazoni Andresa Ribeiro , Fonseca Tania Mara Galli
Published: January 2012

A Oficina de Criatividade, criada em 1990 no Hospital Psiquiátrico São Pedro (RS), constitui-se como espaço que possibilita a criação artística a usuários portadores de sofrimento mental. A partir do Acervo da Oficina de Criatividade, iniciamos uma pesquisa cartográfica da Coleção Luiz Guides, um dos frequentadores. Interessa-nos explorar os limites sensíveis entre vida e obra de um sujeito enclausurado há 60 anos no regime manicomial. Buscamos, então, uma exploração sobre as forças que atravessam esse corpo e cujas marcas de tinta nos apontam não somente aos gestos, mas também à criação de territórios existenciais.
Fenômeno histérico ou psicossomático?: Re-lendo o homem dos lobos com Winnicott
Authors: Pinheiro Nadja Nara Barbosa , Maia Maria Vitória Mamede
Published: January 2012

O objetivo é o de produzirmos uma reflexão teórica sobre os adoecimentos psicossomáticos que nos permita enfrentar seus impasses clínicos tomando como referências Freud e Winnicott. O estudo da angústia como afeto que funda as relações soma/psique nos levou ao estudo da Histeria de Angústia trabalhada, por Freud, no caso clínico do Homem dos Lobos, onde as afecções intestinais foram entendidas como um fenômeno histérico. Propomos sobrepor a essa hipótese que podemos entendê-las, também, como um adoecimento psicossomático como Winnicott o concebe: uma defesa psíquica diante de um movimento de des-integração das malhas psicossomáticas. Destaca-se que encontramos nos autores fundamentos teórico/clínicos para as afecções psicossomáticas.