bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementation of Thermal-Energy-Harvesting Technology on Pavement
Authors: Kim Jaehong , Lee Seung-Tae , Yang Sunglin , Lee Jaejun
Published: February 2016

Energy harvesting is one of the techniques of high interest for approaching the global energy problem without depleting natural resources. Energy-harvesting technology from the road is a new research area, because the energy surrounding road space is available in many different forms, such as wind, solar, thermal, and mechanical energy. The goal of this study is to determine the possibility of an energy-harvesting technology for pavement that absorbs the solar radiation, thus increasing the internal temperature. There is a temperature difference maintained between the atmospheric temperature and the pavement surface. This temperature difference is tapped and converted into electrical energy using a thermoelectric (TE) module device. The TE module device's system captures energy from this temperature difference, based on the Seebeck effect. This paper describes various application procedures for pavement. The system focuses on the development of an energy-harvesting system for energy use. The present research indicates that the limited simple system in this study can be used to capture heat energy from pavement, and shows promise for supporting power from waste solar energy in roads. Also, the TE module can be placed within road space, whereas solar panels have to be exposed to sunlight.
Investigation on 3D 1-mm Pavement-Surface-Model-Based AASHTO PP69-10 Rutting Parameters
Authors: Qiu S. , Wang K. C. P. , Wang W. , Li J. Q.
Published: February 2016

Rutting measurement is critical to modern pavement modeling and management. Over the years, pavement rutting has been measured manually or using limited-point automated devices. However, such lagging technologies and outdated protocols have led to the “rutting depth”-only convention, which compromises the application of rutting data. Recently, the new three-dimensional (3D) 1-mm pavement-surface model produced with a novel system is capable of providing pavement engineers full-lane-width high-resolution transverse profiles for rutting analysis. Multiple rutting characteristics, such as rutting cross-sectional area and deformation, can be consistently derived based on the new AASHTO protocol PP69-10. To provide insight into PP69-10 rutting parameters, bulks of transverse profile data collected from the Arkansas National Highway System (NHS) are analyzed in this study. The value range of PP69-10 deformation parameter is modeled in this study and the relationship of rutting depth measured with the traditional method and the new PP69-10 method is established. Furthermore, the correlations among different PP69-10 rutting attributes are examined. Results presented in this study will be helpful to highway agencies in shifting the state of the practice of rutting measurement.
Influence of Non-Metallic Inclusions on the Fracture-Toughness Properties on the Longitudinal Welding of an API 5L Steel Pipeline
Authors: Angeles-Herrera D. , Albiter-Hernández A. , Cuamatzi-Meléndez R. , Morales-Ramirez A. de J.
Published: February 2016

In previous works, it was demonstrated that the average fracture-toughness values were higher in the circumferential-longitudinal direction (CL) than in the circumferential-radial direction (CR) on the longitudinal submerged arc welding (SAW) in API 5L pipeline steel. Nevertheless, such differences in fracture-toughness values were attributed to the density distribution of microstructural phases and porosity, but the effect of non-metallic inclusions on this fracture property was not considered; therefore, the present work analyzed the effect of non-metallic inclusions on the fracture-toughness values by fractographic and electron diffraction scattered analyses. The results showed the presence of titanium (Ti), calcium (Ca), and aluminum (Al) constituents in the non-metallic inclusions for the CR direction of the pipeline. These elements tended to form compounds that promoted brittle-fracture by cleavage, decreasing the toughness properties of the weld. For the CL direction analysis, the elements presented on the non-metallic inclusions were manganese (Mn), silicon (Si), and sulfur (S), which promoted the nucleation and coalescence of cavities, all of which were typical for ductile fracture. Calculations on the KIC showed that the non-metallic inclusions with elements of Ti, Ca, and Al contributed to lower KIC values on the CR direction under analysis.
Ruggedness Study of Dynamic Modulus Testing of Asphalt Concrete in Indirect Tension Mode
Authors: Norouzi Amirhossein , Kim Y. Richard
Published: February 2016

The modulus is one of the primary asphalt mixture properties used for the mechanistic performance prediction of asphalt pavements. Dynamic modulus testing is a common method of measuring mixture modulus as a function of loading frequencies and temperatures. This paper presented the results of a ruggedness study of dynamic modulus testing in indirect tension mode to evaluate the factors that were most likely to affect the final results. Specimen thickness, air void content, gauge length, test temperature, and horizontal strain level, which are the critical factors that affect the dynamic modulus of asphalt concrete, were selected for the ruggedness analysis. Two different asphalt mixtures with the participation of two laboratories were used in the study. Based on the selected values for the different variables, air void content was found to be the significant factor that affected dynamic modulus testing and dynamic modulus values. The other factors did not appear to have a major impact on the test results; however, reasonable tolerances were obtained for the other parameters investigated in this paper.
Effect of the Welan Gum Biopolymer on Rheological Properties and Storage Stability of Bitumens
Authors: Tu Liang-Liang , Wu Shao-Peng , Liu Gang , Zhou Xin-Xing , Ma Shan-Kui
Published: February 2016

The welan gum, as a biopolymer, is commonly used in the cement mortar to control bleeding and prevent segregation due to its long-chain molecules. This paper studied the effect of welan gum on the rheological behavior of base bitumen and the storage stability of bitumen modified with montmorillonite (MMT). Four contents (0.2, 0.5, 1, and 3 % by weight) of welan gum were used to mix with base bitumen at a suitable temperature of 160°C. The dynamic shear rheometer was adopted to evaluate the viscosity as the function of shear rate. The results indicated that the welan gum, especially with 0.5 % by weight, notably reinforced the shear-thinning behavior of base bitumen at 135 and 160°C. It implied that the welan gum can improve the drainage resistance of asphalt mixture during storage and transportation. Based on this result, the storage stability of MMT modified bitumens with and without 0.5 % welan gum by weight was characterized by the difference in the complex modulus (G*) and the phase angle (δ) of bitumen sampled from the top and bottom layer of the storage tube. The result indicated that the welan gum can apparently improve the storage stability of the MMT modified bitumen.
Comparative Study of Methods to Measure the Density of Cementitious Powders
Authors: Helsel Michelle A. , Ferraris Chiara F. , Bentz Dale
Published: February 2016

The accurate measurement of the density of hydraulic cement plays an essential role in the determination of concrete mixture proportions. As more supplementary cementitious materials (SCM), such as fly ash and slag, or cement replacement materials, such as limestone and calcium carbonate, are used in blended cements, knowledge of the density of each powder or of the blended cement would allow a more accurate calculation of the proportions of a concrete mixture by volume instead of by mass. The current ASTM standard for measuring cement density is ASTM C188-14 “Test Method for Density of Hydraulic Cements,” which utilizes a liquid displacement method to measure the volume of the cement. This paper examined advantageous modifications of the current ASTM test by alcohol substitutions for kerosene. In addition, a gas (helium) pycnometry method was evaluated as a possible alternative to the current standard. The described techniques were compared to determine the most precise and reproducible method for measuring the density of hydraulic cements and other powders.
Prioritization-Optimization Process Algorithm to Manage Pavement Networks During the Non-Availability of Historical Data
Authors: Kitaha A. , Biligiri K. Prapoorna
Published: February 2016

A common practice followed to rate the pavement surface condition is to use the ASTM D5340-12 procedure and estimate the pavement condition index (PCI) that helps prioritize maintenance needs and assists developing a pavement management system (PMS). However, ASTM-PCI that is dependent on time-based evaluation may not be suitable where there is a lack of historical records and it is being undertaken for the first time. To estimate a pavement's current PCI during the non-availability of historical data and establish a PMS incorporated with prioritized maintenance and optimized budget, a rational engineering criteria (EC) based methodological approach is required that is as robust as ASTM D5340-12. Thus, the objective of this study was to develop a rational EC-based prioritization-optimization process PMS (POPMS) algorithm for a network that prioritizes maintenance strategies for identified pavement distresses and hence optimizes maintenance costs depending on budgetary allocations. An EC-based POPMS algorithm was based on a network length of 100.55 km, which followed prioritization-optimization process for single to multi-year programs. EC-PCI of pavement sections were estimated on the basis of segmented maintenance strategies including preventive and routine maintenance and reconstruction. EC-PCI was found to be rational since three distinct threshold zones were considered that could directly assign pavement maintenance strategies, which was straightforward and circularly referenced. Overall, POPMS algorithm facilitates practitioners to modify the threshold EC-based parameters that will estimate an optimal single/multiyear budget for maintenance as per the newly set threshold level, thus creating a whole new promising approach in the areas of roadway network level maintenance programs.
Thermally Activated Healing of Fatigue Damage in Asphalt Binders
Authors: Liu Quantao , Tang Jin , He Liang
Published: February 2016

Asphalt binder is a self-healing material and it has a potential to heal faster with increased temperatures. This paper investigates the thermally activated healing of fatigue damage in three asphalt binders, trying to answer the question: At what temperatures do asphalt binders heal? After fatiguing the sample, a heating treatment was applied and the sample was fatigued for the second time. The recovered fatigue life and the recovered accumulated dissipated energy are used to quantify the thermally activated healing rates of asphalt binders. It is found that these two healing indexes coincide well with each other in different healing conditions. Base asphalt binders can heal the fatigue damage completely after heating for 20 min at the softening-point temperatures. Styrene–butadiene–styrene (SBS)-modified asphalt binder can achieve full healing at a temperature 20°C below its softening point, where the elastic recovery of the SBS chain segment may play an important role in healing. It is also found that healing of fatigue damage in asphalt binder is highly strain dependent: the healing ratio is higher at high strain amplitude. It proved that thermally activated healing can be repeated when damage returns in asphalt binder. It is concluded that thermally activated healing of fatigue damage is definitely useful to increase the fatigue life of asphalt binders and different asphalt binders should be heated to certain temperatures related to their specific softening points.
Metabotropic Glutamate Receptors Induce a Form of LTP Controlled by Translation and Arc Signaling in the Hippocampus
Authors: Wang Hui , Ardiles Alvaro O. , Yang Sunggu , Tran Trinh , Posada-Duque Rafael , Valdivia Gonzalo , Baek Min , Chuang Yang-An , Palacios Adrian G. , Gallagher Michela , Worley Paul , Kirkwood Alfredo
Published: February 2016

Activity-dependent bidirectional modifications of excitatory synaptic strength are essential for learning and storage on new memories. Research on bidirectional synaptic plasticity has largely focused on long-term potentiation (LTP) and long-term depression (LTD) mechanisms that rely on the activation of NMDA receptors. In principle, metabotropic glutamate receptors (mGluRs) are also suitable to convert synaptic activity into intracellular signals for synaptic modification. Indeed, dysfunction of a form of LTD that depends on Type I mGluRs (mGluR-LTD), but not NMDARs, has been implicated in learning deficits in aging and mouse models of several neurological conditions, including Fragile X syndrome and Alzheimer's disease. To determine whether mGluR activation can also induce LTP in the absence of NMDAR activation, we examined in hippocampal slices from rats and mice, an NMDAR-independent form of LTP previously characterized as dependent on voltage-gated Ca2+channels. We found that this form of LTP requires activation of Type I mGluRs and, like mGluR-LTD but unlike NMDAR-dependent plasticity, depends crucially on protein synthesis controlled by fragile X mental retardation protein and on Arc signaling. Based on these observations, we propose the coexistence of two distinct activity-dependent systems of bidirectional synaptic plasticity: one that is based on the activity of NMDARs and the other one based on the activation of mGluRs.

SIGNIFICANCE STATEMENTBidirectional changes of synaptic strength are crucial for the encoding of new memories. Currently, the only activity-dependent mechanism known to support such bidirectional changes are long-term potentiation (LTP) and long-term depression (LTD) forms that relay on the activation of NMDA receptors. Metabotropic glutamate receptors (mGluRs) are, in principle, also suitable to trigger bidirectional synaptic modifications. However, only the mGluR-dependent form of LTD has been characterized. Here we report that an NMDAR-independent form of LTP, initially characterized as dependent on voltage-gated Ca2+channels, also requires the activation of mGluRs. These finding suggest the coexistence of two distinct activity-dependent systems of bidirectional synaptic plasticity: one that is based on the activity of NMDARs and the other one based on the activation of mGluRs.
Left Superior Temporal Gyrus Is Coupled to Attended Speech in a Cocktail-Party Auditory Scene
Authors: Vander Ghinst Marc , Bourguignon Mathieu , Op de Beeck Marc , Wens Vincent , Marty Brice , Hassid Sergio , Choufani Georges , Jousmäki Veikko , Hari Riitta , Van Bogaert Patrick , Goldman Serge , De Tiège Xavier
Published: February 2016

Using a continuous listening task, we evaluated the coupling between the listener's cortical activity and the temporal envelopes of different sounds in a multitalker auditory scene using magnetoencephalography and corticovocal coherence analysis. Neuromagnetic signals were recorded from 20 right-handed healthy adult humans who listened to five different recorded stories (attended speech streams), one without any multitalker background (No noise) and four mixed with a “cocktail party” multitalker background noise at four signal-to-noise ratios (5, 0, −5, and −10 dB) to produce speech-in-noise mixtures, here referred to as Global scene. Coherence analysis revealed that the modulations of the attended speech stream, presented without multitalker background, were coupled at ∼0.5 Hz to the activity of both superior temporal gyri, whereas the modulations at 4–8 Hz were coupled to the activity of the right supratemporal auditory cortex. In cocktail party conditions, with the multitalker background noise, the coupling was at both frequencies stronger for the attended speech stream than for the unattended Multitalker background. The coupling strengths decreased as the Multitalker background increased. During the cocktail party conditions, the ∼0.5 Hz coupling became left-hemisphere dominant, compared with bilateral coupling without the multitalker background, whereas the 4–8 Hz coupling remained right-hemisphere lateralized in both conditions. The brain activity was not coupled to the multitalker background or to its individual talkers. The results highlight the key role of listener's left superior temporal gyri in extracting the slow ∼0.5 Hz modulations, likely reflecting the attended speech stream within a multitalker auditory scene.

SIGNIFICANCE STATEMENTWhen people listen to one person in a “cocktail party,” their auditory cortex mainly follows the attended speech stream rather than the entire auditory scene. However, how the brain extracts the attended speech stream from the whole auditory scene and how increasing background noise corrupts this process is still debated. In this magnetoencephalography study, subjects had to attend a speech stream with or without multitalker background noise. Results argue for frequency-dependent cortical tracking mechanisms for the attended speech stream. The left superior temporal gyrus tracked the ∼0.5 Hz modulations of the attended speech stream only when the speech was embedded in multitalker background, whereas the right supratemporal auditory cortex tracked 4–8 Hz modulations during both noiseless and cocktail-party conditions.
Blockade of Astrocytic Calcineurin/NFAT Signaling Helps to Normalize Hippocampal Synaptic Function and Plasticity in a Rat Model of Traumatic Brain Injury
Authors: Furman Jennifer L. , Sompol Pradoldej , Kraner Susan D. , Pleiss Melanie M. , Putman Esther J. , Dunkerson Jacob , Mohmmad Abdul Hafiz , Roberts Kelly N. , Scheff Stephen W. , Norris Christopher M.
Published: February 2016

Increasing evidence suggests that the calcineurin (CN)-dependent transcription factor NFAT (Nuclear Factor of Activated T cells) mediates deleterious effects of astrocytes in progressive neurodegenerative conditions. However, the impact of astrocytic CN/NFAT signaling on neural function/recovery after acute injury has not been investigated extensively. Using a controlled cortical impact (CCI) procedure in rats, we show that traumatic brain injury is associated with an increase in the activities of NFATs 1 and 4 in the hippocampus at 7 d after injury. NFAT4, but not NFAT1, exhibited extensive labeling in astrocytes and was found throughout the axon/dendrite layers of CA1 and the dentate gyrus. Blockade of the astrocytic CN/NFAT pathway in rats using adeno-associated virus (AAV) vectors expressing the astrocyte-specific promoter Gfa2 and the NFAT-inhibitory peptide VIVIT prevented the injury-related loss of basal CA1 synaptic strength and key synaptic proteins and reduced the susceptibility to induction of long-term depression. In conjunction with these seemingly beneficial effects, VIVIT treatment elicited a marked increase in the expression of the prosynaptogenic factor SPARCL1 (hevin), especially in hippocampal tissue ipsilateral to the CCI injury. However, in contrast to previous work on Alzheimer's mouse models, AAV-Gfa2-VIVIT had no effects on the levels of GFAP and Iba1, suggesting that synaptic benefits of VIVIT were not attributable to a reduction in glial activation per se. Together, the results implicate the astrocytic CN/NFAT4 pathway as a key mechanism for disrupting synaptic remodeling and homeostasis in the hippocampus after acute injury.

SIGNIFICANCE STATEMENTSimilar to microglia, astrocytes become strongly “activated” with neural damage and exhibit numerous morphologic/biochemical changes, including an increase in the expression/activity of the protein phosphatase calcineurin. Using adeno-associated virus (AAV) to inhibit the calcineurin-dependent activation of the transcription factor NFAT (Nuclear Factor of Activated T cells) selectively, we have shown that activated astrocytes contribute to neural dysfunction in animal models characterized by progressive/chronic neuropathology. Here, we show that the suppression of astrocytic calcineurin/NFATs helps to protect synaptic function and plasticity in an animal model in which pathology arises from a single traumatic brain injury. The findings suggest that at least some astrocyte functions impair recovery after trauma and may provide druggable targets for treating victims of acute nervous system injury.
On the Structure of Neuronal Population Activity under Fluctuations in Attentional State
Authors: Ecker Alexander S. , Denfield George H. , Bethge Matthias , Tolias Andreas S.
Published: February 2016

Attention is commonly thought to improve behavioral performance by increasing response gain and suppressing shared variability in neuronal populations. However, both the focus and the strength of attention are likely to vary from one experimental trial to the next, thereby inducing response variability unknown to the experimenter. Here we study analytically how fluctuations in attentional state affect the structure of population responses in a simple model of spatial and feature attention. In our model, attention acts on the neural response exclusively by modulating each neuron's gain. Neurons are conditionally independent given the stimulus and the attentional gain, and correlated activity arises only from trial-to-trial fluctuations of the attentional state, which are unknown to the experimenter. We find that this simple model can readily explain many aspects of neural response modulation under attention, such as increased response gain, reduced individual and shared variability, increased correlations with firing rates, limited range correlations, and differential correlations. We therefore suggest that attention may act primarily by increasing response gain of individual neurons without affecting their correlation structure. The experimentally observed reduction in correlations may instead result from reduced variability of the attentional gain when a stimulus is attended. Moreover, we show that attentional gain fluctuations, even if unknown to a downstream readout, do not impair the readout accuracy despite inducing limited-range correlations, whereas fluctuations of the attended feature can in principle limit behavioral performance.

SIGNIFICANCE STATEMENTCovert attention is one of the most widely studied examples of top-down modulation of neural activity in the visual system. Recent studies argue that attention improves behavioral performance by shaping of the noise distribution to suppress shared variability rather than by increasing response gain. Our work shows, however, that latent, trial-to-trial fluctuations of the focus and strength of attention lead to shared variability that is highly consistent with known experimental observations. Interestingly, fluctuations in the strength of attention do not affect coding performance. As a consequence, the experimentally observed changes in response variability may not be a mechanism of attention, but rather a side effect of attentional allocation strategies in different behavioral contexts.
The Effect of Early Visual Deprivation on the Neural Bases of Auditory Processing
Authors: Guerreiro Maria J. S. , Putzar Lisa , Röder Brigitte
Published: February 2016

Transient congenital visual deprivation affects visual and multisensory processing. In contrast, the extent to which it affects auditory processing has not been investigated systematically. Research in permanently blind individuals has revealed brain reorganization during auditory processing, involving both intramodal and crossmodal plasticity. The present study investigated the effect of transient congenital visual deprivation on the neural bases of auditory processing in humans. Cataract-reversal individuals and normally sighted controls performed a speech-in-noise task while undergoing functional magnetic resonance imaging. Although there were no behavioral group differences, groups differed in auditory cortical responses: in the normally sighted group, auditory cortex activation increased with increasing noise level, whereas in the cataract-reversal group, no activation difference was observed across noise levels. An auditory activation of visual cortex was not observed at the group level in cataract-reversal individuals. The present data suggest prevailing auditory processing advantages after transient congenital visual deprivation, even many years after sight restoration.

SIGNIFICANCE STATEMENTThe present study demonstrates that people whose sight was restored after a transient period of congenital blindness show more efficient cortical processing of auditory stimuli (here speech), similarly to what has been observed in congenitally permanently blind individuals. These results underscore the importance of early sensory experience in permanently shaping brain function.
Single-Cell Detection of Secreted Aβ and sAPPα from Human IPSC-Derived Neurons and Astrocytes
Authors: Liao Mei-Chen , Muratore Christina R. , Gierahn Todd M. , Sullivan Sarah E. , Srikanth Priya , De Jager Philip L. , Love J. Christopher , Young-Pearse Tracy L.
Published: February 2016

Secreted factors play a central role in normal and pathological processes in every tissue in the body. The brain is composed of a highly complex milieu of different cell types and few methods exist that can identify which individual cells in a complex mixture are secreting specific analytes. By identifying which cells are responsible, we can better understand neural physiology and pathophysiology, more readily identify the underlying pathways responsible for analyte production, and ultimately use this information to guide the development of novel therapeutic strategies that target the cell types of relevance. We present here a method for detecting analytes secreted from single human induced pluripotent stem cell (iPSC)-derived neural cells and have applied the method to measure amyloid β (Aβ) and soluble amyloid precursor protein-alpha (sAPPα), analytes central to Alzheimer's disease pathogenesis. Through these studies, we have uncovered the dynamic range of secretion profiles of these analytes from single iPSC-derived neuronal and glial cells and have molecularly characterized subpopulations of these cells through immunostaining and gene expression analyses. In examining Aβ and sAPPα secretion from single cells, we were able to identify previously unappreciated complexities in the biology of APP cleavage that could not otherwise have been found by studying averaged responses over pools of cells. This technique can be readily adapted to the detection of other analytes secreted by neural cells, which would have the potential to open new perspectives into human CNS development and dysfunction.

SIGNIFICANCE STATEMENTWe have established a technology that, for the first time, detects secreted analytes from single human neurons and astrocytes. We examine secretion of the Alzheimer's disease-relevant factors amyloid β (Aβ) and soluble amyloid precursor protein-alpha (sAPPα) and present novel findings that could not have been observed without a single-cell analytical platform. First, we identify a previously unappreciated subpopulation that secretes high levels of Aβ in the absence of detectable sAPPα. Further, we show that multiple cell types secrete high levels of Aβ and sAPPα, but cells expressing GABAergic neuronal markers are overrepresented. Finally, we show that astrocytes are competent to secrete high levels of Aβ and therefore may be a significant contributor to Aβ accumulation in the brain.
Aβ-Induced Synaptic Alterations Require the E3 Ubiquitin Ligase Nedd4-1
Authors: Rodrigues Elizabeth M. , Scudder Samantha L. , Goo Marisa S. , Patrick Gentry N.
Published: February 2016

Alzheimer's disease (AD) is a neurodegenerative disease in which patients experience progressive cognitive decline. A wealth of evidence suggests that this cognitive impairment results from synaptic dysfunction in affected brain regions caused by cleavage of amyloid precursor protein into the pathogenic peptide amyloid-β (Aβ). Specifically, it has been shown that Aβ decreases surface AMPARs, dendritic spine density, and synaptic strength, and also alters synaptic plasticity. The precise molecular mechanisms by which this occurs remain unclear. Here we demonstrate a role for ubiquitination in Aβ-induced synaptic dysfunction in cultured rat neurons. We find that Aβ promotes the ubiquitination of AMPARs, as well as the redistribution and recruitment of Nedd4-1, a HECT E3 ubiquitin ligase we previously demonstrated to target AMPARs for ubiquitination and degradation. Strikingly, we show that Nedd4-1 is required for Aβ-induced reductions in surface AMPARs, synaptic strength, and dendritic spine density. Our findings, therefore, indicate an important role for Nedd4-1 and ubiquitin in the synaptic alterations induced by Aβ.

SIGNIFICANCE STATEMENTSynaptic changes in Alzheimer's disease (AD) include surface AMPAR loss, which can weaken synapses. In a cell culture model of AD, we found that AMPAR loss correlates with increased AMPAR ubiquitination. In addition, the ubiquitin ligase Nedd4-1, known to ubiquitinate AMPARs, is recruited to synapses in response to Aβ. Strikingly, reducing Nedd4-1 levels in this model prevented surface AMPAR loss and synaptic weakening. These findings suggest that, in AD, Nedd4-1 may ubiquitinate AMPARs to promote their internalization and weaken synaptic strength, similar to what occurs in Nedd4-1's established role in homeostatic synaptic scaling. This is the first demonstration of Aβ-mediated control of a ubiquitin ligase to regulate surface AMPAR expression.
Chronic Ampakine Treatments Stimulate Dendritic Growth and Promote Learning in Middle-Aged Rats
Authors: Lauterborn Julie C. , Palmer Linda C. , Jia Yousheng , Pham Danielle T. , Hou Bowen , Wang Weisheng , Trieu Brian H. , Cox Conor D. , Kantorovich Svetlana , Gall Christine M. , Lynch Gary
Published: February 2016

Positive allosteric modulators of AMPA-type glutamate receptors (ampakines) have been shown to rescue synaptic plasticity and reduce neuropathology in rodent models of cognitive disorders. Here we tested whether chronic ampakine treatment offsets age-related dendritic retraction in middle-aged (MA) rats. Starting at 10 months of age, rats were housed in an enriched environment and given daily treatment with a short half-life ampakine or vehicle for 3 months. Dendritic branching and spine measures were collected from 3D reconstructions of Lucifer yellow-filled CA1 pyramidal cells. There was a substantial loss of secondary branches, relative to enriched 2.5-month-old rats, in apical and basal dendritic fields of vehicle-treated, but not ampakine-treated, 13-month-old rats. Baseline synaptic responses in CA1 were only subtly different between the two MA groups, but long-term potentiation was greater in ampakine-treated rats. Unsupervised learning of a complex environment was used to assess treatment effects on behavior. Vehicle- and drug-treated rats behaved similarly during a first 30 min session in the novel environment but differed markedly on subsequent measures of long-term memory. Markov sequence analysis uncovered a clear increase in the predictability of serial movements between behavioral sessions 2 and 3 in the ampakine, but not vehicle, group. These results show that a surprising degree of dendritic retraction occurs by middle age and that this can be mostly offset by pharmacological treatments without evidence for unwanted side effects. The functional consequences of rescue were prominent with regard to memory but also extended to self-organization of behavior.

SIGNIFICANCE STATEMENTBrain aging is characterized by a progressive loss of dendritic arbors and the emergence of impairments to learning-related synaptic plasticity. The present studies show that dendritic losses are evident by middle age despite housing in an enriched environment and can be mostly reversed by long-term, oral administration of a positive allosteric modulator of AMPA-type glutamate receptors. Dendritic recovery was accompanied by improvements to both synaptic plasticity and the encoding of long-term memory of a novel, complex environment. Because the short half-life compound had no evident negative effects, the results suggest a plausible strategy for treating age-related neuronal deterioration.
Color-Biased Regions of the Ventral Visual Pathway Lie between Face- and Place-Selective Regions in Humans, as in Macaques
Authors: Lafer-Sousa Rosa , Conway Bevil R. , Kanwisher Nancy G.
Published: February 2016

The existence of color-processing regions in the human ventral visual pathway (VVP) has long been known from patient and imaging studies, but their location in the cortex relative to other regions, their selectivity for color compared with other properties (shape and object category), and their relationship to color-processing regions found in nonhuman primates remain unclear. We addressed these questions by scanning 13 subjects with fMRI while they viewed two versions of movie clips (colored, achromatic) of five different object classes (faces, scenes, bodies, objects, scrambled objects). We identified regions in each subject that were selective for color, faces, places, and object shape, and measured responses within these regions to the 10 conditions in independently acquired data. We report two key findings. First, the three previously reported color-biased regions (located within a band running posterior–anterior along the VVP, present in most of our subjects) were sandwiched between face-selective cortex and place-selective cortex, forming parallel bands of face, color, and place selectivity that tracked the fusiform gyrus/collateral sulcus. Second, the posterior color-biased regions showed little or no selectivity for object shape or for particular stimulus categories and showed no interaction of color preference with stimulus category, suggesting that they code color independently of shape or stimulus category; moreover, the shape-biased lateral occipital region showed no significant color bias. These observations mirror results in macaque inferior temporal cortex (Lafer-Sousa and Conway, 2013), and taken together, these results suggest a homology in which the entire tripartite face/color/place system of primates migrated onto the ventral surface in humans over the course of evolution.

SIGNIFICANCE STATEMENTHere we report that color-biased cortex is sandwiched between face-selective and place-selective cortex on the bottom surface of the brain in humans. This face/color/place organization mirrors that seen on the lateral surface of the temporal lobe in macaques, suggesting that the entire tripartite system is homologous between species. This result validates the use of macaques as a model for human vision, making possible more powerful investigations into the connectivity, precise neural codes, and development of this part of the brain. In addition, we find substantial segregation of color from shape selectivity in posterior regions, as observed in macaques, indicating a considerable dissociation of the processing of shape and color in both species.
Orexin Neurons Respond Differentially to Auditory Cues Associated with Appetitive versus Aversive Outcomes
Authors: Hassani Oum Kaltoum , Krause Matthew R. , Mainville Lynda , Cordova Christopher A. , Jones Barbara E.
Published: February 2016

Orexin (Orx) neurons are known to be involved in the promotion and maintenance of waking because they discharge in association with cortical activation and muscle tone during waking and because, in their absence, waking with muscle tone cannot be maintained and narcolepsy with cataplexy ensues. Whether Orx neurons discharge during waking in association with particular conditions, notably with appetitive versus aversive stimuli or positive versus negative emotions, is debated and considered important in understanding their role in supporting particular waking behaviors. Here, we used the technique of juxtacellular recording and labeling in head-fixed rats to characterize the discharge of Orx neurons during the performance of an associative discrimination task with auditory cues for appetitive versus aversive outcomes. Of 57 active, recorded, and neurobiotin-labeled neurons in the lateral hypothalamus, 11 were immunohistochemically identified as Orx-positive (Orx+), whereas none were identified as melanin-concentrating hormone-positive. Orx+neurons discharged at significantly higher rates during the tone associated with sucrose than during the tone associated with quinine delivered upon licking. They also discharged at high rates after the tone associated with sucrose. Across periods and outcomes, their discharge was positively correlated with EEG gamma activity and EMG activity, which is indicative of cortical activation and behavioral arousal. These results suggest that Orx neurons discharge in a manner characteristic of reward neurons yet also characteristic of arousal neurons. Accordingly, the Orx neurons may respond to and participate in reward processes while modulating cortical activity and muscle tone to promote and maintain arousal along with learned adaptive behavioral responses.

SIGNIFICANCE STATEMENTOrexin neurons play a critical role in promoting and maintaining a waking state because, in their absence, narcolepsy with cataplexy ensues. Known to discharge during waking and not during sleep, they have also been proposed to be selectively active during appetitive behaviors. Here, we recorded and labeled neurons in rats to determine the discharge of immunohistochemically identified orexin neurons during performance of an associative discrimination task. Orexin neurons responded differentially to auditory cues associated with appetitive sucrose versus aversive quinine, indicating that they behave like reward neurons. However, correlated discharge with cortical and muscle activity indicates that they also behave like arousal neurons and can thus promote cortical activation with behavioral arousal and muscle tone during adaptive waking behaviors.
ACTUALIDAD DE ZUBIRI EN AMÉRICA LATINA
Authors: Marquínez Argote Germán
Published: February 2016

Zubiri ha venido cobrando creciente actualidad en Latinoamérica. Actualidad no significa
estar de moda, sino estar presente. El trabajo da cuenta rigurosamente documentada
de esa presencia, identificando hasta cuatro etapas y determinando los principales
cauces tenidos en cada una de ellas. En la primera, de 1931 a 1936, el gran cauce fue la
Revista de Occidente, de amplia resonancia entre la joven intelectualidad latinoamericana
del momento. La segunda, iniciada en la posguerra española, su principal cauce
fue el libro Naturaleza, Historia, Dios, además de la obra editorial y docente de los
“trasterrados”, como José Gaos y María Zambrano, entre otros. La tercera, inaugurada
en 1962, año de publicación de Sobre la esencia, de positiva recepción por pensadores
como el mexicano Agustín Basabe, el chileno Jorge Ribera, Ignacio Ellacuría en El
Salvador y el propio Germán Marquínez en Colombia. Finalmente, la cuarta, arranca
con la publicación de la Trilogía sobre la inteligencia, 1980-1983, en la cual se vienen
destacando tres grupos de investigación zubiriana establecidos en El Salvador, Colombia
y Chile, respectivamente.
LA IDEA DE CIENCIA EN MIGUEL ANTONIO CARO
Authors: Tovar Leonardo
Published: February 2016

El artículo analiza la concepción de Miguel Antonio Caro en torno a la ciencia. En el primer apartado se reseñan las críticas del pensador bogotano contra la filosofía positivista, que en sus tres versiones (el positivismo de Comte, el evolucionismo biológico de Darwin y el evolucionismo social de Spencer) pretende poner las hipótesis científicas por encima de las verdades de la religión. A continuación, se expone la doctrina católica del autor en torno al verdadero saber científico, que en coincidencia con Meléndez Pelayo, Caro estima necesariamente afín a la fe. Para concluir, se discute la visión reaccionaria de Caro sobre la ciencia moderna, ya que ésta ha estado en la base de la mentalidad anticientífica de la educación en Colombia.
FENOMENOLOGÍA DEL CUERPO HUMANO
Authors: Villamil Pineda Miguel Ángel
Published: February 2016

Uno de los problemas fundamentales planteados por la ciencia y la filosofía occidental
es el que se refiere al ser del hombre. Las respuestas dadas a este problema han girado
alrededor de concepciones idealistas y materialistas. La fenomenología nos pone de
presente que estas representaciones, al radicalizar sus posturas, resultan insuficientes,
ya que, por dar prioridad al cuerpo o a la subjetividad, destotalizan la unidad integral
del ser humano. La experiencia nos muestra al hombre como un ser corporal unitario
que se manifiesta como: expresión de una subjetividad; vía de acceso al mundo de las
cosas; “punto cero” de todas las experiencias; órgano transformador de la realidad;
órgano de socialización; órgano axiológico. Además, el hombre tiene la posibilidad de
reflexionar, es decir, de volver sobre las experiencias corporales. Así, podemos ver que
la experiencia corporal y la experiencia reflexiva son los dos modos de ser fundamentales
de una misma constitución humana. No “tenemos” un cuerpo, somos cuerpo; no
pensamos “desde” el cuerpo, ni “a través” del cuerpo, pensamos como cuerpo, pensamos
corporalmente.
CONSIDERACIONES SOBRE LA FILOSOFÍA DE LA HISTORIA EN HEGEL
Authors: Díaz Jorge Aurelio
Published: February 2016

Una visión sobre la filosofía de la historia de Hegel exige considerarla en la triple perspectiva
que ofrece su Sistema: la objetiva de los Cursos de Berlín, la subjetiva de la
Fenomenología y la absoluta o especulativa de la Enciclopedia. Al integrar esas perspectivas,
la historia viene a ser el lugar para considerar las relaciones entre el Estado y
la Religión, y se manifiesta como expresión suprema del Espíritu finito en su larga travesía
en pos de la libertad.
LA EXPERIENCIA DEL LENGUAJE EN LA LITERATURA: ANOTACIONES A LA FILOSOFÍA DE MERLEAU-PONTY
Authors: Verano Gamboa Leonardo
Published: February 2016

En la literatura, y en general en el arte, se muestra lo propio del lenguaje: la experiencia
de la palabra como acontecimiento de creación de sentido. El lenguaje de la literatura
tiene el poder de crear nuevos sentidos y mundos posibles, donde el sentido de la palabra
no se agota en su función de representación, porque es originariamente experiencia del
mundo de la vida. Este planteamiento se desarrolla en tres momentos: 1. Introducción:
Se presentan los presupuestos de la concepción metafísica del lenguaje, particularmente
los expuestos por el racionalismo y el empirismo filosóficos. 2. Mundo de la vida y literatura:
A partir de la obra de Stendhal y de Balzac se argumenta por qué el decir de la
literatura, antes que ser narración de hechos y personajes, habla del encuentro del hombre
con el mundo. 3. La actualidad como decir de la obra: Tomando como ejemplo la
obra de Proust se explica cómo en la experiencia de lectura de la obra literaria su ser
actual se vive como auténtica creación de sentido.
VIDA Y MUNDO: REFLEXIÓN A PARTIR DE DILTHEY Y HUSSERL
Authors: Palacio Manuel
Published: February 2016

Tras la caída de los grandes sistemas idealistas, la reflexión filosófica se tornó hacia el
problema metafísico fundamental que había dejado el idealismo: el problema de las
relaciones del sujeto con el mundo. Las relaciones que se establecen entonces ya no son
puramente epistemológicas sino que devienen en antropológicas y ontológicas. La dicotomía
entre hombre y mundo se sintetiza en el concepto de vida como unidad estructural
caracterizada por ser una conexión. En este orden de ideas, el problema fundamental es
el de señalar las relaciones introspectivas de la misma estructura de la vida, es decir,
analizar las relaciones entre vida y mundo a partir de los primeros filósofos que se
ocuparon del tema, a saber, Dilthey y Husserl.
RASKOLNIKOV: BÚSQUEDA DE LA AUTOAFIRMACIÓN DESDE LA DESESPERACIÓN
Authors: Chamorro Nuñez Nathalie
Published: February 2016

En el presente ensayo se busca considerar a Raskolnikov como un ser desesperado desde
la óptica de Hegel, al debatirse entre su deseo y la realidad. También se parte de que
toda desesperación debe llevar a una acción que brinde la salida a la encrucijada, y se
desea dejar en claro que esta salida es el amor como una superación de la misma filosofía
hegeliana, al considerar que el individuo puede llegar a un autoconocimiento desde
su propia autoafirmación y a la vez es la superación del mismo Raskolnikov dentro de su
moral egoísta.
Estrategias Pedagógicas para la Motivación Lectora a Través de un Software de Lectura Interactiva
Authors: Vásquez César Augusto , Romero Amparo , Molina Ruth Yamile
Published: February 2016

La ponencia presenta el diseño y la construcción de un módulo de estrategias pedagógicas para la motivación de lectura de textos narrativos en el grado Transición del Colegio Liceo Miguel de Cervantes Saavedra, del municipio de Fusagasugá (Cundinamarca). El módulo pedagógico tiene como finalidad motivar la lectura a través de guías complementarias y creativas para la aplicación del software educativo Lectura interactiva, elaborado por Olga Patricia Parra (2000).
La Resolución de Problemas y el Pensamiento Numérico en los Procesos de Enseñanza- Aprendizaje Significativos de la División
Authors: Alonso Sandra Peña
Published: February 2016

Este proyecto de investigación responde a la necesidad pedagógica, didáctica y disciplinar de brindar a los estudiantes del curso 6° B del Colegio Rafael María Carrasquilla (Bogotá, localidad 18) alternativas para generar un aprendizaje significativo en el proceso de la división y de su concepto fundamental de reparto. Para tal fin se elaboró una cartilla en la que se presentan situaciones problemáticas, creadas a partir de diferentes experiencias en la escuela, las cuales constituyen el insumo necesario para que los educandos conciban la construcción de su conocimiento como una fuente de incertidumbres, reflexiones, preguntas, conflictos y espacios de socialización.
Presupuestos teóricos y conceptuales que posibilitan un análisis del perfil del docente de humanidades: el caso de la Universidad Santo Tomás de Bogotá
Authors: Arias Murillo Francisco Antonio
Published: February 2016

Este artículo muestra la forma docente que propicia la Universidad Santo Tomás teniendo en cuenta las políticas del Estado colombiano y las propias de la institución, tendientes a constituir un sujeto educado profesionalmente. Se apoya en parte de la investigación “La emergencia del hombre en la formación de maestros en Colombia: segunda mitad del siglo XX”, producida por el autor; desde ahí busca visibilizar las condiciones en las que se produce la formación profesional en la USTA y entender la tarea educativa-formativa que le corresponde al Departamento de Humanidades para contribuir a la realización de la misión institucional. El artículo presenta un análisis del texto “Educación y liberación en América Latina” como evidencia del proceder arqueológico que como metodología se utilizó en el desarrollo de la investigación.

Palabras clave: forma docente, formación profesional, misión institucional, arqueología.
La internacionalización de la educación superior, factor clave para fortalecer la calidad educativa y mejorar las condiciones de vida de la sociedad
Authors: Cerón Jesús Salvador Moncada
Published: February 2016

La internacionalización de la educación superior se ha convertido en una dinámica novedosa que ha de integrarse a las funciones clásicas de las instituciones educativas, en afinidad a un conocimiento sin fronteras que se desarrolla en el escenario de la globalización. Al incorporar la dimensión internacional e intercultural se promueve un incremento en la calidad educativa, a la vez que se imponen retos a la estructura y gestión universitaria respecto a sus problemáticas en torno a la investigación, la docencia, el servicio a la comunidad y la autonomía. Al considerar tales desafíos, la clave de una nueva universidad deberá basarse en el desarrollo humano sustentable, la cultura de paz, la solidaridad y una educación permanente, todo ello a partir de una transformación significativa del sistema de educación superior, soporte estratégico del desarrollo.