bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Visual Cortex Responses to Rapid Cone and Melanopsin-Directed Flicker
Authors: Spitschan Manuel , Datta Ritobrato , Stern Andrew M. , Brainard David H. , Aguirre Geoffrey K. 
Published: February 2016

Signals from cones are recombined in postreceptoral channels [luminance, L + M; red-green, L − M; blue-yellow, S − (L + M)]. The melanopsin-containing retinal ganglion cells are also active at daytime light levels and recent psychophysical results suggest that melanopsin contributes to conscious vision in humans. Here, we measured BOLD fMRI responses to spectral modulations that separately targeted the postreceptoral cone channels and melanopsin. Responses to spatially uniform (27.5° field size, central 5° obscured) flicker at 0.5, 1, 2, 4, 8, 16, 32, and 64 Hz were recorded from areas V1, V2/V3, motion-sensitive area MT, and the lateral occipital complex. In V1 and V2/V3, higher temporal sensitivity was observed to L + M + S (16 Hz) compared with L − M flicker (8 Hz), consistent with psychophysical findings. Area MT was most sensitive to rapid (32 Hz) flicker of either L + M + S or L − M. We found S cone responses only in areas V1 and V2/V3 (peak frequency: 4–8 Hz). In addition, we studied an L + M modulation and found responses that were effectively identical at all temporal frequencies to those recorded for the L + M + S modulation. Finally, we measured the cortical response to melanopsin-directed flicker and compared this response with control modulations that addressed stimulus imprecision and the possibility of stimulation of cones in the shadow of retinal blood vessels (penumbral cones). For our stimulus conditions, melanopsin flicker did not elicit a cortical response exceeding that of the control modulations. We note that failure to control for penumbral cone stimulation could be mistaken for a melanopsin response.SIGNIFICANCE STATEMENTThe retina contains cone photoreceptors and ganglion cells that contain the photopigment melanopsin. Cones provide brightness and color signals to visual cortex. Melanopsin influences circadian rhythm and the pupil, but its contribution to cortex and perception is less clear. We measured the response of human visual cortex with fMRI using spectral modulations tailored to stimulate the cones and melanopsin separately. We found that cortical responses to cone signals vary systematically across visual areas. Differences in temporal sensitivity for achromatic, red-green, and blue-yellow stimuli generally reflect the known perceptual properties of vision. We found that melanopsin signals do not produce a measurable response in visual cortex at temporal frequencies between 0.5 and 64 Hz at daytime light levels.
Nonspatial Sequence Coding in CA1 Neurons
Authors: Allen Timothy A. , Salz Daniel M. , McKenzie Sam , Fortin Norbert J. 
Published: February 2016

The hippocampus is critical to the memory for sequences of events, a defining feature of episodic memory. However, the fundamental neuronal mechanisms underlying this capacity remain elusive. While considerable research indicates hippocampal neurons can represent sequences of locations, direct evidence of coding for the memory of sequential relationships among nonspatial events remains lacking. To address this important issue, we recorded neural activity in CA1 as rats performed a hippocampus-dependent sequence-memory task. Briefly, the task involves the presentation of repeated sequences of odors at a single port and requires rats to identify each item as “in sequence” or “out of sequence”. We report that, while the animals' location and behavior remained constant, hippocampal activity differed depending on the temporal context of items—in this case, whether they were presented in or out of sequence. Some neurons showed this effect across items or sequence positions (general sequence cells), while others exhibited selectivity for specific conjunctions of item and sequence position information (conjunctive sequence cells) or for specific probe types (probe-specific sequence cells). We also found that the temporal context of individual trials could be accurately decoded from the activity of neuronal ensembles, that sequence coding at the single-cell and ensemble level was linked to sequence memory performance, and that slow-gamma oscillations (20–40 Hz) were more strongly modulated by temporal context and performance than theta oscillations (4–12 Hz). These findings provide compelling evidence that sequence coding extends beyond the domain of spatial trajectories and is thus a fundamental function of the hippocampus.SIGNIFICANCE STATEMENTThe ability to remember the order of life events depends on the hippocampus, but the underlying neural mechanisms remain poorly understood. Here we addressed this issue by recording neural activity in hippocampal region CA1 while rats performed a nonspatial sequence memory task. We found that hippocampal neurons code for the temporal context of items (whether odors were presented in the correct or incorrect sequential position) and that this activity is linked with memory performance. The discovery of this novel form of temporal coding in hippocampal neurons advances our fundamental understanding of the neurobiology of episodic memory and will serve as a foundation for our cross-species, multitechnique approach aimed at elucidating the neural mechanisms underlying memory impairments in aging and dementia.
Estradiol-Mediated Spine Changes in the Dorsal Hippocampus and Medial Prefrontal Cortex of Ovariectomized Female Mice Depend on ERK and mTOR Activation in the Dorsal Hippocampus
Authors: Tuscher Jennifer J. , Luine Victoria , Frankfurt Maya , Frick Karyn M. 
Published: February 2016

Dendritic spine plasticity underlies the formation and maintenance of memories. Both natural fluctuations and systemic administration of 17β-estradiol (E2) alter spine density in the dorsal hippocampus (DH) of rodents. DH E2infusion enhances hippocampal-dependent memory by rapidly activating extracellular signal-regulated kinase (ERK)-dependent signaling of mammalian target of rapamycin (mTOR), a key protein synthesis pathway involved in spine remodeling. Here, we investigated whether infusion of E2directly into the DH drives spine changes in the DH and other brain regions, and identified cell-signaling pathways that mediate these effects. E2significantly increased basal and apical spine density on CA1 pyramidal neurons 30 min and 2 h after infusion. DH E2infusion also significantly increased basal spine density on pyramidal neurons in the medial prefrontal cortex (mPFC) 2 h later, suggesting that E2-mediated activity in the DH drives mPFC spinogenesis. The increase in CA1 and mPFC spine density observed 2 h after intracerebroventricular infusion of E2was blocked by DH infusion of an ERK or mTOR inhibitor. DH E2infusion did not affect spine density in the dentate gyrus or ventromedial hypothalamus, suggesting specific effects of E2on the DH and mPFC. Collectively, these data demonstrate that DH E2treatment elicits ERK- and mTOR-dependent spinogenesis on CA1 and mPFC pyramidal neurons, effects that may support the memory-enhancing effects of E2.SIGNIFICANCE STATEMENTAlthough systemically injected 17β-estradiol (E2) increases CA1 dendritic spine density, the molecular mechanisms regulating E2-induced spinogenesisin vivoare largely unknown. We found that E2infused directly into the dorsal hippocampus (DH) increased CA1 spine density 30 min and 2 h later. Surprisingly, DH E2infusion also increased spine density in the medial prefrontal cortex (mPFC), suggesting that estrogenic regulation of the DH influences mPFC spinogenesis. Moreover, inhibition of ERK and mTOR activation in the DH prevented E2from increasing DH and mPFC spines, demonstrating that DH ERK and mTOR activation is necessary for E2-induced spinogenesis in the DH and mPFC. These findings provide novel insights into the molecular mechanisms through which E2mediates dendritic spine density in CA1 and mPFC.
Principles Governing DNA Methylation during Neuronal Lineage and Subtype Specification
Authors: Sharma Ali , Klein Shifra Liba , Barboza Luendreo , Lodhi Niraj , Toth Miklos 
Published: February 2016

Although comprehensively described during early neuronal development, the role of DNA methylation/demethylation in neuronal lineage and subtype specification is not well understood. By studying two distinct neuronal progenitors as they differentiate to principal neurons in mouse hippocampus and striatum, we uncovered several principles governing neuronal DNA methylation during brain development. (1) The program consists of three stages: an initial genome-wide methylation during progenitor proliferation is followed by loss of methylation during the transition of regional progenitors to “young” hippocampal/striatal neurons, which is then reversed by gain in methylation during maturation to subtype-specific neurons. (2) At the first two stages, gain and loss of methylation are limited to CpGs, whereas during the third maturation stage, methylation also occurs at non-CpG sites in both lineages. (3) Methylation/demethylation, similar to transcription, are initially highly similar in the two lineages, whereas diversification in methylation and transcription during maturation creates subtype-specific methylation differences. (4) Initially, methylation targets all genomic locations, whereas later, during early and late differentiation, the preferred targets are intronic/intergenic sequences with enhancer-like activity. (5) Differentially methylated genes are enriched in sequential neurodevelopmental functions (such as progenitor proliferation, migration, neuritogenesis, and synaptic transmission); upregulated genes represent current and consecutive stage-specific functions, and downregulated genes represent preceding functions that are no longer required. The main conclusion of our work is that the neuronal methylation/demethylation program is predominantly developmental with minimal lineage specificity, except in the final stage of development when neuron subtype-specific differences also emerge.SIGNIFICANCE STATEMENTOur work is the first to describe a set of relatively simple rules that govern DNA methylation and demethylation in neuronal developmentin vivo. By dividing neurodevelopment to three major stages and applying rules to each of them, we created a matrix that comprehensively describes DNA methylation/demethylation events in two neuronal lineages, with a total of 10 cell types spanning the entire neurodevelopment. Beyond increasing our understanding of the epigenetic regulation of normal development, our work will be useful in deciphering how environmental perturbations, such as gestational toxins, drugs, stress, infection, and offspring neglect/maltreatment, interfere with the developmental methylation program.
Time to insulin initiation and long-term effects of initiating insulin in people with type 2 diabetes mellitus: the Hoorn Diabetes Care System Cohort Study
Authors: Mast Ruth , Danielle Jansen A P , Walraven Iris , Rauh Simone P , van der Heijden Amber A W A , Heine Robert J , Elders Petra J M , Dekker Jacqueline M , Nijpels Giel , Hugtenburg Jacqueline G 
Published: February 2016

ObjectiveThe aim of this study was to assess the time to insulin initiation in type 2 diabetes mellitus (T2DM) patients treated with oral glucose-lowering agents and to determine the baseline characteristics associated with time to insulin initiation. This was evaluated in T2DM patients with HbA1c levels consistently ≥7.0% during total follow up and in those with fluctuating HbA1c levels around 7.0%.Design and methodsProspective, observational study was performed, comprising 2418 persons with T2DM aged ≥40 years who entered the Diabetes Care System between 1998 and 2012 with a minimum follow up of at least 3 years, following the first HbA1c level ≥7.0%. Cox regression analyses were performed to assess the determinants of time to insulin initiation. Data related to long-term effects of insulin initiation were studied at baseline and at the end of follow up using descriptive summary statistics.ResultsTwo-thirds of the patients initiated insulin during follow up. The time to insulin varied from 1.2 years (range 0.3–3.1) in patients with HbA1c levels consistently ≥7.0% to 5.4 years (range 3.0–7.5) in patients with fluctuating HbA1c levels around 7.0%. Longer diabetes duration (hazard ratio (HR) 1.04 95% CI 1.03–1.05) and lower age (HR 1.00 95% CI 0.99–1.00) at baseline were associated with a shorter time to initiation. More insulin initiators had retinopathy compared with patients that remained on oral glucose-lowering agents during follow up.ConclusionThe time to insulin initiation was short, and most of the patients with HbA1c levels consistently ≥7.0% were initiating insulin. Longer diabetes duration and younger age shortened the time to insulin.
La identidad docente: constantes y desafíos
Authors: García Carlos Marcelo 
Published: February 2016

<p align="justify">La docencia como profesión está sufriendo cambios debidos a la evolución de las demandas de la sociedad hacia los sistemas educativos, así como por los cambios en la manera de apropiarse de lo que concede legitimidad al profesorado: el conocimiento. La cultura profesional docente, como la de casi todas las profesiones, es reacia a los cambios. Pero necesariamente hemos de evolucionar para seguir siendo una profesión imprescindible en nuestras sociedades. La identidad profesional docente se caracteriza por unas señas de identidad que intentamos revisar a lo largo de este artículo. Una profesión docente en la que la socialización previa influye en las creencias que el profesorado desarrolla, en la que el contenido que se enseña crea identidad, con una clara predilección por el conocimiento práctico y el aprender de la experiencia, caracterizada por el aislamiento, y en donde los alumnos son la principal fuente de motivación del profesorado. La carrera docente, generalmente plana, también caracteriza a la profesión docente, en la que el profesorado se percibe a sí mismo como artesano, y donde está mal visto pedir ayuda y recibir retroalimentación, con poca confianza por las tecnologías, y que descuida la atención a los docentes que empiezan.</p>
Introducing Issue Two
Authors: Khanenko-Friesen Natalia 
Published: February 2016

The Engaged Scholar Journal's second issue “Quality of Life: Towards Sustainable Community Futures” highlights, once again, Canada’s rich and diverse scholarship of community-university collaborations in research, teaching, and learning. We thank our guest editors, Isobel M. Findlay and Nazeem Muhajarine, for taking intellectual and conceptual leadership in the production and development of this strong collection of timely essays that together focus and advance the idea of communities’ quality of life. ‘Quality of life’ is a broadly defined term used in qualitative and quantitative research in various areas of applied scholarship that focus on community development, health, human resources, leisure, and other areas of human life.
Reflections on the Opportunities and Challenges of Youth Engagement: Youth and Professional Perspectives
Authors: Iwasaki Yoshitaka , Dashora Pushpanjali , McHugh Tara-Leigh , McLaughlin Anne-Marie , Springett Jane 
Published: February 2016

This paper documents the opportunities and challenges experienced by youth leaders and community agency partners in our community-based research project on youth engagement. Participants provided reflective statements, based on their experiences during the course of this multi-year project. Specifically, these insights focused on (a) youth-oriented and collaborative research processes (for example highlighting youth voice—“bottom-up process for youth by youth,” and co-learning and team work); (b) group dynamics (for example, common purpose, dealing with transformation, relationship and trust-building, and power issues); and (c) benefits for community youth-serving agencies and youth themselves, for example, capacity-building, grounded in youth experiences through participatory research, and knowledge translation and practical application—advancing research into action). The process of being involved in this research was coined an “amazing journey” to facilitate positive change and transformation within the youth and community partners. Understanding such youth engagement issues has implications for better supporting high-risk youth and their families in order to enhance the quality of their lives in a meaningful, sustainable way.
“Taking Risks” with Literacy Acoustics
Authors: Crandall Bryan Ripley 
Published: February 2016

<p>This article is a May 28, 2015, National Writing Project (NWP) interview with Newbery Award-winning author Kwame Alexander about contributions he made to yearlong professional development collaboration between K-8 teachers at Hill Central in New Haven, Connecticut, and Connecticut Writing Project at Fairfield University. The interview, <em>A Talk With Kwame Alexander</em>, is available in its entirety via BlogTalkRadio. <em></em></p>
From Bootstraps to Hands-up: A Multicultural Content Analysis of The Depiction of Poverty in Young Adult Literature
Authors: Hill Crag , Darragh Janine J. 
Published: February 2016

<p>This article describes the findings of a qualitative critical multicultural content analysis of 71 young adult (YA) novels depicting poverty and published between 1996 when the Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA) was signed into law by President Bill Clinton and 2013. The study answers three research questions: In what ways does YA literature published after the PRWORA portray poverty? How do those representations compare to current statistics regarding poverty in the United States? What do these depictions mean for teachers of English? The authors urge that instructors who use novels that depict poverty in preservice and/or graduate courses in young adult literature help build awareness of the complexity of poverty. </p>
Perspectiva bioética y modelo biopsicosocial en la relación odontólogo-paciente durante la formación del estudiante en la Universidad El Bosque
Authors: Rangel Galvis María Clara 
Published: February 2016

En este artículo presentamos una revisión en torno a la importancia de la enseñanza de la relación odontólogo-paciente, describimos los dilemas que se evidencian en la literatura sobre el desarrollo de éstas prácticas, realizamos un ejercicio reflexivo a partir de los lineamientos que rigen el currículo en la Facultad de Odontología de la Universidad el Bosque bajo el enfoque del modelo biopsicosocial; complementado con un programa transcurricular en bioética, formación que a pesar de tener esta orientación holística, parecen existir tensiones entre el modelo de formación y las prácticas formativas en los últimos semestres en la asistencia o en la relación estudiante-paciente-docente, repercutiendo en serias implicaciones bioéticas. A partir de esta discusión se plantean algunas de las dificultades en la apropiación del modelo y se proponen acciones para mejorar la implementación exitosa de este en la formación docente-asistencial
Staphylococcal Scalded Skin Syndrome: A Case Review
Authors: Hennigan Kourtney , Riley Cheryl 
Published: February 2016

ABSTRACTStaphylococcal scalded skin syndrome (SSSS) is a rare yet well-known exfoliative skin syndrome. It involves extensive desquamated areas caused by an exfoliative toxin from Staphylococcus aureus. The typical presentation of SSSS allows for early diagnosis and treatment of the disease. Knowing and understanding the prevalence, pathophysiology, risk factors, and diagnosis of SSSS will ensure that infants being treated and cared for by neonatal nurses and neonatal nurse practitioners will receive appropriate, comprehensive, and multidisciplinary care while in the NICU. The purpose of this case review is to inform neonatal nurses and practitioners of the current literature that focuses on the diagnosis and management of SSSS.
Relationship Between Crude Oil Prices And Economic Growth In Selected OPEC Countries
Authors: Ftiti Zied , Guesmi Khaled , Teulon Frédéric Teulon , Chouachi Slim 
Published: February 2016

<p>The aim of this study is to examine the degree of interdependence between oil prices and economic activity growth for four major countries (United Arab Emirates, Kuwait, Saudi Arabia, and Venezuela) in the Organization of the Petroleum Exporting Countries (OPEC) over the period from 3 September 2000 to 3 December 2010. We propose the frequency approach of Priestley and Tong (1973), which is the evolutionary co-spectral analysis. This method offers a time-varying dynamic correlation measure for different horizons, short-run and medium-run. To complete our study by analyzing long-run dependence, we use the cointegration procedure developed by Engle and Granger (1987). We show that oil price shocks in periods during period of fluctuations in the global business cycle and/or financial turmoil affect the relationship between oil and economic growth in OPEC countries.</p>
R&D Narrative Disclosure, Corporate Governance And Market Value: Evidence From France
Authors: Nekhili Mehdi , Hussainey Khaled , Cheffi Walid , Chtioui Tawhid , Tchakoute-Tchuigoua Hubert 
Published: February 2016

<p>We investigate the impact of R&amp;D narrative disclosure on the market value of equity for a sample of French companies during the period 2000–2004. Using 3SLS estimation on a panel data of 98 French firms, we find, ceteris paribus, positive (but insignificant) association between R&amp;D voluntary disclosure and the market value of equity. Both R&amp;D intensity and R&amp;D capitalization lead French firms to disclose more R&amp;D narrative information. However, they impact differently the relationship between R&amp;D-related disclosure and market value. Indeed, a positive and significant association is found when we control for R&amp;D capitalization. In contrast, when controlling for R&amp;D intensity, we find a negative association. We also find that equity-based compensation and audit committee independence are the most important drivers for R&amp;D narrative disclosure. </p>
Does The Expectations Hypothesis Explain The Term Structure Of Treasury Bond Yields In Tunisia?
Authors: Boukhatem Jamel 
Published: February 2016

<p><em>This paper tests the expectations hypothesis (EH) using monthly data for Treasury bond yields (TBYs) over the period 1994m5–2014m12 and ranging in maturity from one year to 10 years. We apply cointegrated-VAR jointly on more than one pair of yields. The results suggest rejection of the EH throughout the medium maturity spectrum. However, for longer maturities they suggest the validity of the EH for the TBYs. This indeed confirms the smooth functioning of Tunisian bond market which gives an indication that the yield curve should serve as an indicator to the monetary policymakers to manage inflation and to influence the aggregate demand in the economy.</em></p><p><strong> </strong></p>
The January Effect Anomaly Reexamined In Stock Returns
Authors: Patel Jayen B. 
Published: February 2016

<p>We examined the presence of January effect in international stock returns for the recent time period, January 1997 to December 2014. Our results provide conclusive evidence that January effect no longer exists in stock returns during recent years. These results were remarkably consistent when we investigated existence of January effect by sub-periods separating the time period of 2008-09 when stock market largely plummeted internationally. The results of this study support growing literature that indicates January effect does not exist anymore in stock returns. <strong></strong></p>