bluuebunny/crossref_metadata_2025 huggingface dataset:
Problems of Gifted and Talented Students Regarding Cursive Handwriting: Parent Opinions
Authors: Kadioglu-Ates Hatice
Published: April 2018

We are living in an age where knowledge is rapidly produced and consumed. In this period, the future of the individual and the society depends on accessing, using and producing information. This situation requires a qualified education and first literacy teaching which is the foundation of it. Primary school is the foundation of everything; likewise, the first literacy learning is the foundation of learning (Gunes, Uysal and Tac, 2016). First literacy is to create a new communication and interaction channel for the individual by teaching the symbols of humankind that it created in ten thousand years. Education performs a great miracle by making a seven-year old child comprehend this script that humankind developed in ten thousand years within a seven- or eight-month period (Guleryuz, 2001). It is desired for and expected of the children who start the first grade in primary school at the level of illiteracy to reach the level of basic literacy with qualified first literacy education under the supervision of an effective program, equipped teacher (Sagirli, 2015). Education in cursive handwriting in our country has started in Ataturk era. Ataturk demonstrated examples of the New Turkish Latin Letters on the blackboard with the cursive handwriting. Elderly and young people of the generation of Ataturk era have learned the cursive handwriting very well and used for many years. Many documents of that period such as diplomas, identity cards, registry of deeds etc. have been prepared with cursive handwriting in a clear, cursive and aesthetic form (Gunes, 2006). In our country, it has been decided to start the first literacy education with the cursive handwriting under the scope of the 2004 draft program. For nearly thirteen years, our students are becoming literate with cursive handwriting. There are many studies in literature that examine the opinions of teachers, students, and parents about the cursive handwriting. The aim of the concerned study is to express the view from the perspective of the parents of the gifted and talented students on the practice of cursive handwriting in first literacy education. Within the scope of the research, interviews were conducted with the parents of the gifted and talented students and their opinions were taken about starting the first literacy with the practice of the cursive handwriting. All of the parents are the parents of gifted and talented children who are attending primary school. The data collected during the 2016-2017 academic year have been obtained by face-to-face interviews. The answers of the parents are recorded and then reported. Screening model is used in the study that is designed by content analysis. The research is a qualitative study. Recommendations are brought at the end of the research.
A Study of Curriculum Literacy and Information Literacy Levels of Teacher Candidates in Department of Social Sciences Education
Authors: Sural Serhat , Dedebali Nurhak Cem
Published: April 2018

The present study aims to investigate information literacy and curriculum literacy levels of teacher candidates and to identify the relationship between them through their course of study at Faculty of Education. The research model was designed as quantitative one and general screening model was employed. The study group is 895 students, who were reached out of teacher candidates, attending the third and fourth grade in the Classroom Education, Preschool Education, Science Education and Social Sciences Education Departments of Pamukkale University and Sinop University in the 2017-2018 academic year. To achieve the goal of this research study, “Information Literacy Scale” and “Curriculum Literacy Scale” were used. In light of results obtained from the study, it is observable that there are meaningful differences between information literacy and curriculum literacy of teacher candidates in terms of the variables identified. Further, the mean of items measuring teacher candidates’ levels of information and curriculum literacy were examined and their levels of “frequency” and “agree” were determined. Ultimately, correlation analysis was performed between information literacy and curriculum literacy and positive relationship was determined at the low, medium and high levels. Also, predictive power of the level of information literacy on the level of curriculum literacy was tested. Aforesaid these four variables together explain 34% of the change in curriculum literacy levels.
Why Should Bilingualized Dictionary of Turkish Be Used in Teaching Turkish as a Foreign Language?
Authors: Baskin Sami
Published: April 2018

The first person to learn Turkish as a foreign language is a Chinese woman writing Turkish love letters for her exiled husband in the 4th century. However, we do not know much about how this woman learned Turkish. The known history of teaching Turkish as a Foreign Language goes back to the first concrete material produced for this process. They are usually bilingual dictionaries and the oldest one was written in the 11th century. It is therefore more accurate to say that teaching Turkish as a Foreign Language has a history of nearly a thousand years. The changing educational paradigm since the 20th century has deeply influenced the teaching of language, which was previously carried out in accordance with the grammar – translation method. And, dictionaries ceased to be the main device for language teaching and became a source of complementary materials in learning environment, which has necessitated their re-regulation. Yet, Turkish dictionary authors continue to maintain old habits and produce classical bilingual dictionaries. The bilingual dictionaries, proven to be more helpful on second language teaching, have been used across the world from the 1980s onwards. In this paper, the history of the teaching Turkish as a Foreign Language is briefly explained by taking into consideration the resources used in the second language teaching and then answers are given to the questions "Why should bilingualized dictionaries be used in the teaching Turkish as a Foreign Language" and "How should two bilingual dictionaries be prepared?".
Equilibrium federal impotence: why the states and not the American national government financed economic development in the antebellum era
Authors: Wallis John Joseph , Weingast Barry R.
Published: April 2018

Why did states dominate investments in economic development in early America? Between 1787 and 1860, the national governments spent $54 million on transportation infrastructure while the states spent $450 million. Using models of legislative choice, we show that Congress could not finance projects that provided benefits to a minority of districts while spreading the taxes over all. Although states faced the same political problems, they used benefit taxation schemes that coordinated taxation and benefits – for example, by assessing property taxes on the basis of the increase in value due to an infrastructure investment. The US Constitution required the federal government to allocate direct taxes on the basis of population, effectively prohibiting benefit taxation. As a result, federal government expenditures were concentrated in collections of small projects – such as lighthouses and rivers and harbours – that spent money in all districts. Federal inaction was the result of the equilibrium political forces in Congress, and hence an equilibrium impotence.
Stop crying over spilt knowledge: a critical look at the theory of spillovers and technical change
Authors: Langlois Richard N. , Robertson Paul L.
Published: April 2018

In this essay we analyze critically the idea of knowledge spillovers. We call into question much of the web of syllogism involved in both the microeconomic and aggregate versions of the theory. We certainly do not deny the reality of knowledge spillovers, or that they may be important under certain circumstances. But we do dispute the policy conclusions of the mainstream view of these matters by questioning the plausibility of the assumptions on which the conclusions are laid. Our criticisms fall into two broad categories. Our efforts, however, are not directed mainly towards intellectual (creative) destruction. We also make the affirmative case that spillovers can have a positive value for innovators and that a sensible economics of spillovers may be sought at the microeconomic level in the developing literature on strategic capabilities.
Characterization of physical properties of aerosols atmospheric on regions affected by burning biomass in Brazil
Authors: Rothmund Lucas Douglas , Palácios Rafael Da Silva , Marques João Basso , Oliveira Lúcio Gonçalves Barbosa , Rodrigues Thiago Rangel , Curado Leone Francisco Amorim , Nogueira José De Souza
Published: April 2018

Este estudo teve como objetivo caracterizar as propriedades físicas dos aerossóis no norte e centro-oeste do Brasil. Estas regiões são fortemente impactadas pela sazonalidade das propriedades físicas e químicas dos aerossóis, devido principalmente aos altos níveis de queima de biomassa durante a estação seca. A análise foi realizada em quatro sites da rede AERONET, dois no bioma amazônico e dois na savana (conhecida localmente como cerrado) para verificar a possível diferença entre as propriedades dos aerossóis da queima de floresta e pastagem no cerrado brasileiro. Foram utilizados dados de nível 1.5 de janeiro de 2000 a julho de 2015. Houve variação sazonal da profundidade ótica de aerossóis na faixa de 675 nm (AOD 675 nm) em todos os locais estudados, com os picos alcançados na estação seca devido à grande contribuição de partículas provenientes da queima de biomassa. Os valores de albedo de espalhamento simples na faixa de 675 nm (SSA 675 nm) mostraram pouca variação, mesmo da mudança da estação chuvosa para seca. Observou-se que os valores de SSA para as regiões localizadas no bioma do cerrado foram ligeiramente menores do que os valores obtidos para os demais sites localizados no bioma amazônico. As contribuições de partículas provenientes da queima de biomassa durante a estação seca sobre a região amazônica aumentam substancialmente as propriedades da dispersão da radiação na atmosfera. Sobre Cuiabá e Campo Grande (cerrado) observou-se que na estação chuvosa há predominância de emissões urbanas e poeira do solo e na estação seca partículas de queima de biomassa. No entanto, para a estação seca verificou-se que o material particulado nessas regiões é mais absorvedor que os aerossóis presentes nas regiões do bioma amazônico.
Caracterização hidroquímica e isotópica das águas, na porção sudoeste do Quadrilátero Ferrífero no município de Congonhas-MG, e sua correlação com a localização em cota das unidades aquíferas deste sistema
Authors: Paula Rodrigo Sergio , Mesquita Daniele Costa de , Dantas Julia Cotta Maciel , Guerra Kênia Janete
Published: April 2018

O presente artigo consiste em uma análise de dados hidroquímicos e isotópicos em águas do Aquífero Cauê, na região de Congonhas, MG, com o objetivo de caracterizar o aquífero e compreender a dinâmica das águas. Foram identificados 3 grupos, cuja diferenciação se dá pela concentração de íons. A metodologia aplicada consistiu na análise de quatro campanhas de amostragem executadas nos anos de 2004, 2006, 2010 e 2013. Os resultados hidroquímicos foram tratados no software AquaChem por meio de diagramas de classificação das águas. Os resultados isotópicos foram avaliados e correlacionados  com a cota de localização das amostras coletadas. O Grupo 1 representa as amostras com maior concentração de íons e o Grupo 3 as de menor concentração. As águas são predominantemente bicarbonatadas cálcicas magnesianas, ligeiramente ácidas a neutras. A concentração de trítio apresenta-se de forma muito heterogênea, variando desde 1,8 UT até menor que 0,2 UT. A análise deste dado permitiu uma diferenciação baseada na profundidade x concentração de trítio. As anomalias encontradas após esta separação estão relacionadas a um fluxo existente nas falhas da região.
Diagrammatic iconicity explains asymmetries in Paamese possessive constructions
Authors: Devylder Simon
Published: April 2018

Grammatical asymmetries in possessive constructions are overtly coded in about 18% of the world’s languages according to the World Atlas of Language Structures What primarily motivates these grammatical asymmetries is controversial and has been at the crux of the “iconicity vs. frequency” debate This paper contributes to this debate by focusing on the grammatical asymmetries of Paamese possessive constructions, and looking for the primary motivating factor in their multidimensional experiential context. After a careful account of four experiential dimensions of distance (functional, affective, sociopragmatic, and embodied), the degrees of experiential distance are shown to systematically correspond to the degrees of formal distance of the possessive constructions used to refer to these experiences (e.g., direct or indirect suffixation of kinship and body part terms). Relevant anthropological and linguistic data concerning Paamese is used to explore whether this correspondence between language and experience is primarily motivated by iconicity or economy. I argue that diagrammatic iconicity is the primary motivating factor for the grammatical asymmetries in Paamese possessive constructions, and that economy can account for some, but not all cases. I also show that economy and iconicity can collaborate in motivating some cases, and thus do not necessarily need to be opposed.
Dual Segment Glocal Model Based Capacitive Level Sensor (CLS) for Adhesive Material and Level Detection
Authors: Khan F. A. , Yousaf A. , Reindl L. M.
Published: April 2018

This paper presents a multi segment capacitive level monitoring sensor based on distributed E-fields approach Glocal. This approach has an advantage to analyze build-up problem by the local E-fields as well the fluid level monitoring by the global E-fields. The multi segment capacitive approach presented within this work addresses the main problem of unwanted parasitic capacitance generated from Copper (Cu) strips by applying active shielding concept. Polyvinyl chloride (PVC) is used for isolation and parafilm is used for creating artificial build-up on a CLS.
Design, Fabrication and Test of Modified Septum Antennas for Satellite Telecommunication
Authors: Fazaelifar Mohammad , Jam Shahrokh , Basiri Raheleh , Azadi H. Reza
Published: April 2018

In this paper at first, the ordinary septum polarizer has been designed and used for parabolic reflector feed in Ground station antenna. Next, a novel design of modified septum polarizer with wider beam-width is proposed for satellite antenna. Compactness, low weight, large bandwidth, high TX/RX isolation, low axial ratio as well as low loss are the advantages of the septum polarizer. The designed antenna has high purity circular polarization (

$\left| {AR} \right| \le 1.6dB$
) and low return loss. The frequency bandwidth of the antenna is about 27 % in the center frequency 11 GHz and the TX/RX isolation is better than 32 dB. Finally the septum polarizer, modified septum polarizer and reflector are fabricated and tested and there were good agreement between simulation and measurement results.
Miniaturized Bandpass Filter with Wide Stopband using Spiral Configuration of Stepped Impedance Resonator
Authors: Singh Vivek , Killamsetty Vinay Kumar , Mukherjee Biswajeet
Published: April 2018

In this letter, a miniaturized Band Pass Filter (BPF) with wide stopband centered at 0.350 GHz for TETRA band applications is proposed using a Spiral Short Circuit quarter wavelength Stepped Impedance Resonator (SSC-SIR) and a stub loaded on feed line for enhancement of rejection level in the stopband. Spiral configuration of the resonator is used for the miniaturization of BPF. The proposed BPF provides a 3dB fractional bandwidth of 13.7 % with two transmission zeros in the lower and upper stopband to provide good selectivity and four transmission zeros which provide wide stopband upto 6.86f0. Proposed BPF has a very compact size of 0.064λg×0.062λg.
A Bayesian Framework for Estimating the Concordance Correlation Coefficient Using Skew-elliptical Distributions
Authors: Feng Dai , Baumgartner Richard , Svetnik Vladimir
Published: April 2018

The concordance correlation coefficient (CCC) is a widely used scaled index in the study of agreement. In this article, we propose estimating the CCC by a unified Bayesian framework that can (1) accommodate symmetric or asymmetric and light- or heavy-tailed data; (2) select model from several candidates; and (3) address other issues frequently encountered in practice such as confounding covariates and missing data. The performance of the proposal was studied and demonstrated using simulated as well as real-life biomarker data from a clinical study of an insomnia drug. The implementation of the proposal is accessible through a package in the Comprehensive R Archive Network.
Synthesis and Modification of Zeolite ZSM-5 Catalyst with Solutions of Calcium Carbonate (CaCO3) and Sodium Carbonate (Na2CO3) for Methanol to Gasoline Conversion
Authors: Kianfar Ehsan , Salimi Mahmoud , Pirouzfar Vahid , Koohestani Behnam
Published: April 2018

In this article, the ZSM-5 catalyst was used as the base catalyst and its structure was modified for conducting Methanol to Gasoline reactions. ZSM-5 catalyst reacts to the solutions with diverse concentrations of calcium carbonate (CaCO3) and sodium carbonate (Na2CO3), and consequently, some changes were applied to its internal structure. Thus, Methanol to Gasoline (MTG) process was carried out under pressure of 1 atm, the temperature of 400°C, and specific surface area of 300 m2g-1 on synthetic zeolite ZSM-5 catalyst by a fixed-bed reactor. Structure and morphology of the synthesized catalyst were investigated by XRD, FT-IR, SEM, XRF and BET analyses. The effect of CaCO3 and Na2CO3 solutions used for catalyst modification on the distribution of hydrocarbon products were studied and compared to ZSM-5 catalyst. The result of catalyst activity evaluation tests shows that the modified catalyst with a 0.1 molar solution of CaCO3 and Na2CO3 provides the highest selectivity and efficiency compared to the hydrocarbons in boiling point range of C6+ gasoline.
Modeling of Supersonic/Hypersonic Boundary Layer Transition Using a Single-Point Approach
Authors: Qiao Lei , Bai Jun-Qiang , Xu Jia-Kuan , Xu Jing-Lei , Zhang Yang
Published: April 2018

During the process of aerodynamic shape design of supersonic and hypersonic space planes, laminar flow design and boundary layer transition prediction play important roles in aero-thermal numerical simulations and aero-thermal protection design. Therefore, in this study, a computational fluid dynamics compatible transition closure model for high speed laminar-to-turbulent transitional flows is formulated with consideration of the analysis results from stability theory. The proposed model contains two transport equations to describe the transition mechanism using local variables. Specifically, the eddy viscosity of laminar fluctuations and intermittency factor are chosen to be the characteristic parameters and modeled by transport equations. Accounting for the dominant instability modes at supersonic/hypersonic conditions, the first- and second- modes are modeled using local variables through the analysis of laminar self-similar boundary layers. Then, the present transition model is applied with compressibility corrected

k

$k$

-

ω

$\omega$

shear stress transport turbulence model. Thus, as the main significance of the current work, the present model is enabled to capture the overshoot phenomena as well as predict the transition onset position. Finally, comparisons between the predictions using the present model and the wind tunnel experimental results of several well-documented flow cases are provided to validate the proposed transition turbulence model.
Institution and market: Orders of multiple languages in Indonesian vocational education
Authors: Tamtomo Kristian
Published: April 2018

Indonesian vocational secondary education reflects the increasingly multilingual demands of globalized education and labor market. This study focuses on two orders of multiple languages that are present in vocational high schools in Semarang, Central Java. It aims not only to describe the different orders of languages, but also to suggest that each order represents differing strategies of dealing with the demands of globalization. One order represents the state-backed institutional approach, which views multiple languages as distinct entities and demands students to have monolingual competence in English, Indonesian, and Javanese to engage in globalization, cultivate nationalism and preserve tradition. The other order represents the market-oriented way vocational schools meet the demands of globalized industries and labor markets by directly adopting the multilingual industry register into local learning processes.
Crystal structure of catena-poly[diaqua-bis(di(N
2,N
6-dihydroxypyridine-2,6-dicarboxamide))potassium(I)]tetrahydrate, C14H25N6O14K
Authors: Zuo Jian
Published: April 2018

C14H25N6O14K, triclinic, P1̅ (no. 2), a = 6.9630(15) Å, b = 9.2770(17) Å, c = 9.6100(18) Å, α = 69.822(2)°, β = 87.225(2)°, γ = 85.559(2)°, V = 580.8(2) Å3, Z = 1, R
gt(F) = 0.0366, wR
ref(F
2) = 0.1052, T = 293(2) K.
Crystal Structure of bis(1-(phenylsulfonyl)-2-(1-(pyrazin-2-yl)ethylidene)hydrazin-1-ido-κ3
N,N′,O)copper(II), C24H22N8O4S2Cu
Authors: Wang Wan-Wan , Wu Wei-Na , Wang Yuan
Published: April 2018

C24H22N8O4S2Cu, orthorhombic, Aba2 (no. 41), a = 11.9395(18) Å, b = 21.813(3) Å, c = 10.1184(15) Å, V = 2635.2(7) Å3, Z = 4, R
gt(F) = 0.0395, wR
ref(F
2) = 0.0912, T = 296(2) K.
El cine político puro: la ficción como inspiración - reflejo de la espectacularización política / The pure political cinema: the fiction as inspiration - reflection of political spectacularization
Authors: Rodríguez Vidales Yolanda , Padilla Castillo Graciela
Published: April 2018

La relación entre la ficción y la política es palpable en cientos de títulos cinematográficos, desde el nacimiento del cine hasta nuestros días. La espectacularización democrática, o politainment, es vital en la comunicación política, inspirada por la ficción, y viceversa. El cine se convierte en inspiración y, al mismo tiempo, reflejo de la realidad, como queda de manifiesto, por ejemplo, en que las productoras abran cuentas de redes sociales para políticos ficticios –personajes de sus series- que hacen comentarios muy calculados sobre política real. Atendiendo a la tipología de películas políticas de Christensen y Haas (2005) y concretamente, al tipo de film político puro, desgranamos cinco cintas norteamericanas, íntimamente relacionadas con el entorno de su momento y precursoras visionarias de la espectacularización que vendría después a caracterizar a la industria del cine. Son El Candidato (The Candidate, 1972), Power (1986), La cortina de humo (Wag the dog, 1997), Primary Colors (1998) y Los idus de marzo (The idus of March, 2011), de cinco décadas distintas. Todas abordan el uso y manejo de las apariencias y el espectáculo como forma de obtener el poder o consolidarlo en un sentido político y real de la expresión. Confirman que la política está condicionada por los medios de comunicación, el espectáculo y el escepticismo –o carencia de él- del público.
Martínez Navarro, G. (2017). Marketing ycomunicación de moda. Madrid, ESIC
Authors: Padilla Castillo Graciela
Published: April 2018

La moda ha acompañado al ser humano a lo largo de la historia del ser humano, siendo un reflejo visible de los valores de cada momento histórico. La moda es arte, es cultura, nos aporta sensaciones, placeres y emociones, forma parte de nuestro tiempo de ocio y nos ayuda a expresar nuestra personalidad, nuestros valores y nuestra forma de sentirnos y entender la vida. Dejando al margen el lado afectivo, la industria de la moda representa un activo importantísimo dentro de la economía global, y se ha convertido en un importante motor de crecimiento económico en muchos países. Con estas ideas previas, Gema Martínez Navarro nos presenta un libro interesantísimo, actual, original y necesario. Establece y sistematiza científicamente una parcela innovadora: comunicación y marketing de la moda.
Cloning and expression of an Aplysia K+ channel and comparison with native Aplysia K+ currents
Authors: Pfaffinger PJ , Furukawa Y , Zhao B , Dugan D , Kandel ER
Published: April 2018

We describe here the cloning of the Aplysia K+ channel AK01a.AK01a codes for a protein of 515 amino acids, shows considerable homology to other cloned potassium channels, and can be classified as a member of the ShakerK+ channel family. Expression of the AK01a channel in Xenopus oocytes produces a rapidly inactivating outward potassium current (IAK01a) resembling the A-type currents of Drosophila Shaker. Gating for this current is shifted to potentials considerably more positive than the traditional A-currents of Aplysia; we have, however, identified a novel transient potassium current (IAdepoI) in a subset of Aplysia neurons that has similar gating and pharmacological properties to IAK01a.
N-methyl-D-aspartate antagonists prevent kainate neurotoxicity in rat retinal ganglion cells in vitro
Authors: Sucher NJ , Aizenman E , Lipton SA
Published: April 2018

Under defined culture conditions, exogenous glutamate (Glu), NMDA, or an endogenous Glu-related toxin is lethal to rat retinal ganglion cells; these detrimental effects are NMDA receptor mediated because specific NMDA antagonists can prevent cellular injury. In the presence of an endogenous Glu-like toxin, 125 microM kainate (KA) increases the proportion of retinal ganglion cells that die, but the toxicity (due to both KA and the endogenous toxin) is totally prevented by 2-amino-5- phosphonovalerate (APV), a specific NMDA receptor antagonist. These findings indicate that the KA-induced portion of retinal ganglion cell death also appears to be mediated via NMDA receptors. There are at least 2 possible mechanisms for this lethal effect. In addition to KA receptors, KA could directly stimulate NMDA receptors. Alternatively, KA might activate its own specific receptor, which in turn leads to a net increase in the release of an endogenous Glu-related toxin; this endogenous substance would then activate NMDA receptors. Patch-clamp electrophysiology experiments have helped to distinguish between these possibilities. Concentrations of APV that completely block the current elicited by maximal nondesensitizing doses of NMDA exert no detectable inhibition of KA-evoked currents. Hence, at the concentrations used, it appears unlikely that KA directly activates NMDA receptors in this preparation. Furthermore, the fraction of toxicity attributed to the addition of KA can be blocked by the relatively specific non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). This finding is consistent with the hypothesis that KA adds an increment of toxicity in this system by directly interacting with KA receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
Distribution of Ca2+ channels on frog motor nerve terminals revealed by fluorescent omega-conotoxin
Authors: Cohen MW , Jones OT , Angelides KJ
Published: April 2018

Tetramethylrhodamine-conjugated omega-conotoxin was used as a fluorescent stain (Jones et al., 1989) to determine the spatial distribution of voltage-gated Ca2+ channels along frog motor nerve terminals. Like native omega-conotoxin, the fluorescent toxin blocked neuromuscular transmission irreversibly. The fluorescent staining was confined to the neuromuscular junction and consisted of a series of narrow bands (in face views) or dots (in side views) approximately 1 micron apart. This characteristic staining pattern was prevented by pretreatment with omega-conotoxin and by prior denervation for 5–7 d. Combined fluorescence and phase-contrast optics indicated that the stain was on the synaptic rather than the nonsynaptic side of the nerve terminal. The bands and dots of stain proved to be in spatial register with the postsynaptic junctional folds, as revealed by combined staining of ACh receptors. It is concluded that the voltage-gated Ca2+ channels on frog motor nerve terminals are concentrated at active zones. The findings are consistent with the suggestion (Heuser et al., 1974; Pumplin et al., 1981) that the large intramembraneous particles seen at freeze-fractured active zones are voltage-gated Ca2+ channels.
Matching neural and muscle oscillators: control by FMRFamide-like peptides
Authors: Meyrand P , Marder E
Published: April 2018

Stomatogastric nervous systems of the shrimp, Palaemon serratus, were stained with antisera raised against the peptide FMRFamide. FMRFamide- like immunoreactivity was found in fibers in the input nerve to the stomatogastric ganglion (STG), in several STG somata, in dense neuropil in the STG, in the motor nerves that innervate the dilator muscles of the pyloric region, but not in the pyloric dilator (PD) motor neurons. FMRFamide and several FMRFamide-like peptides elicited sequences of rhythmic depolarizations and contractions of the pyloric dilator muscle. As peptide concentrations were increased, a discrete threshold for contraction was found, above which contractions were initiated with a decreasing latency in an all-or-none fashion. Muscles stopped rhythmically contracting after many seconds to several minutes of activity; the duration of spontaneous oscillatory activity in peptide was proportional to the concentration of applied peptide. In the absence of peptide, each motor neuron discharge evoked small graded muscle contractions. During peptide-induced oscillations, motor neuron activity did not always entrain muscle oscillations. After spontaneous oscillations had stopped, when the motor neurons were stimulated in the presence of the peptide, each motor neuron burst evoked large amplitude contractions as a result of the peptide-induced regenerative properties of the muscle membrane.
Beta subunit coexpression and the alpha1 subunit domain I-II linker affect piperidine block of neuronal calcium channels
Authors: Zamponi GW , Soong TW , Bourinet E , Snutch TP
Published: April 2018

The effects of local anesthetics were examined on a family of transiently expressed neuronal calcium channels. Fomocaine, a local anesthetic containing a morpholine ring, preferentially blocked alpha1E channels (Ki = 100 microM), and had a lower affinity (3- to 15-fold) for alpha1A, alpha1B, and alpha1C channels. Block was incompletely reversible, followed 1:1 kinetics, and did not affect steady-state inactivation properties. Fomocaine block was sensitive to the concentration of permeant ion and enhanced in the presence of external pore blockers, suggesting a site of action in the conducting pathway. Flecainide, which carries a piperidine ring, and the diphenylbutylpiperidine antipsychotic, penfluridol, caused qualitatively similar block, suggesting that morpholine rings are compatible with the piperidine receptor site. In contrast, procaine, which contains an alkyl chain, caused reversible low affinity block of the different calcium channels (Kd values between 2 and 5 mM) and was least effective on alpha1E and did not compete with fomocaine, suggesting that local anesthetics interact with at least two distinct receptor sites. Compared to coexpression with the Ca channel beta1b subunit, block at the piperidine receptor site was significantly weakened with the beta2a subunit suggesting that the nature of the beta subunit contributes to drug binding. Amino acid changes in the cytoplasmic linker between domains I and II resulted in decreased fomocaine and penfluridol blocking affinity. Furthermore, the blocking affinity observed with alpha1B, was conferred on alpha1A by substitution of the domain I-II linker of alpha1B into alpha1A. Taken together, the data suggest that beta subunit binding and the domain I- II linker contribute to the piperidine receptor site on neuronal calcium channels.
Narp, a novel member of the pentraxin family, promotes neurite outgrowth and is dynamically regulated by neuronal activity
Authors: Tsui CC , Copeland NG , Gilbert DJ , Jenkins NA , Barnes C , Worley PF
Published: April 2018

Stimulus-linked RNA and protein synthesis is required for establishment of long-term neuroplasticity. To identify molecular mechanisms underlying long-term neuroplasticity, we have used differential cDNA techniques to clone a novel immediate-early gene (IEG) that is rapidly induced in neurons of the hippocampus and cortex by physiological synaptic activity. Analysis of the deduced amino acid sequence indicates homology to members of the pentraxin family of secreted lectins that include C-reactive protein and serum amyloid P component. Regions of homology include an 8 amino acid “pentraxin signature” sequence and a characteristic pentraxin calcium-binding domain. We have termed this gene and the encoded protein Narp (from neuronal activity- regulated pentraxin). Biochemical analyses confirm the presence of a functional signal sequence, and Narp is secreted by transfected COS-1 cells in culture. Additionally, Narp binds to agar matrix in a calcium- dependent manner consistent with the lectin properties of the pentraxin family. When cocultured with Narp-secreting COS-1 cells, neurons of cortical explants exhibit enhanced growth of neuronal dendritic processes. Neurite outgrowth-promoting activity is also observed using partially purified Narp and can be specifically immunodepleted, demonstrating that Narp is the active principle. Narp is fully active at a concentration of approximately 40 ng/ml, indicating a potency similar to known peptide growth factors. Because Narp is rapidly regulated by neuronal activity, its lectin and growth-promoting activities are likely to play role in the modification of cellular properties that underlie long-term plasticity.
Inhibition of the Kv4 (Shal) family of transient K+ currents by arachidonic acid
Authors: Villarroel A , Schwarz TL
Published: April 2018

We have found that transient A-type currents expressed in Xenopus oocytes from members of the Kv4 family are suppressed by arachidonic acid. Currents from members of the Kv1, Kv2, and Kv3 families showed little or no inhibition by fatty acids in this expression system, although Shaker currents showed a modest increase in peak amplitude. The inhibition of Kv4 channels was not prevented by cyclo-oxygenase, lipoxygenase, or cytochrome P-450 inhibitors and was mimicked by 5,8,11,14-eicosatetraynoic acid, an arachidonic acid analog that is not metabolized by these pathways. Other unsaturated cis fatty acids with more than two double bonds produced a similar effect. In inside-out macropatches, the current was reversibly reduced >50% by 2 microM arachidonic acid, and the inhibition developed in <40 sec. These results suggest that, at concentrations that are likely to be physiologically relevant, arachidonic acid interacts directly with the channel or with a closely associated component. Preliminary mutagenesis of Kv4.2 channels indicates that the N terminal is not required for arachidonic acid action but that the S4-S5 loop may influence the effect.
Acetylcholine-induced potassium current of guinea pig outer hair cells: its dependence on a calcium influx through nicotinic-like receptors
Authors: Blanchet C , Erostegui C , Sugasawa M , Dulon D
Published: April 2018

The cholinergic efferent inhibition of mammalian outer hair cells (OHCs) is mediated by a hyperpolarizing K+ current. We have made whole- cell tight-seal recordings from single OHCs isolated from the guinea pig cochlea to characterize the mechanism by which acetylcholine (ACh) activates K+ channels. After ACh application, OHCs exhibited a biphasic response: an early depolarizing current preceding the predominant hyperpolarizing K+ current. The current-voltage (I-V) relationship of the ACh-induced response displayed an N-shape, suggesting the involvement of Ca2+ influx. When whole-cell recording was combined with confocal calcium imaging, we simultaneously observed the ACh-induced K+ current (IK(ACh)) and a Ca2+ response restricted to the synaptic area of the cell. This IK(ACh) could be prevented by loading OHCs with 10 mM of the fast Ca2+ buffer bis(2-aminophenoxy)ethane-N,N,N′,N′-tetra- acetic acid (or BAPTA), therefore allowing the observation of the ACh- induced early current in isolation. This early current revealed nicotinic features because it activated with an intrinsic delay in the millisecond range, reversed nearly in between potassium and sodium equilibrium potentials, and was blocked by curare. However, it was strongly reduced in the absence of external Ca2+, and its I-V relationship displayed an unusual outward rectification at positive membrane potentials and an inward rectification below -60 mV. The results indicate that the cholinergic response of mammalian OHCs involves a “nicotinic-like” nonspecific cation channel through which Ca2+ enters and triggers activation of nearby Ca2+-dependent K+ channels.
Inhibition of calcium channels in rat central and peripheral neurons by omega-conotoxin MVIIC
Authors: McDonough SI , Swartz KJ , Mintz IM , Boland LM , Bean BP
Published: April 2018

Inhibition of voltage-dependent calcium channels by omega-conotoxin MVIIC (omega-CTx-MVIIC) was studied in various types of rat neurons. When studied with 5 mM Ba2+ as charge carrier, omega-CTx-MVIIC block of N-type calcium channels in sympathetic neurons was potent, with half- block at 18 nM. Block of N-type channels had a rapid onset (tau approximately 1 sec at 1 microM omega-CTx-MVIIC) and quick reversibility (tau approximately 30 sec). The rate of block was proportional to toxin concentration, consistent with 1:1 binding of toxin to channels, with a rate constant (k on) of approximately 1 X 10(6) M-1. sec-1. Both potency and rate of block were reduced dramatically with increasing concentrations of extracellular Ba2+ omega- CTx-MVIIC also blocked P-type calcium channels in cerebellar Purkinje neurons, but both development and reversal of block were far slower than for N-type channels. The rate of block was proportional to toxin concentration, with k on -1.5 x 10(3) M-1. sec-1 at 5 mM Ba2+. From this value and an unblocking time constant of approximately 200 min, a dissociation constant of approximately 50 nM was estimated. Thus, block of P-type channels is potent but very slow. In hippocampal CA3 pyramidal neurons, omega-CTx-MVIIC blocked approximately 50% of the high-threshold calcium channel current; one component (approximately 20%) was blocked with the rapid kinetics expected for N-type channels, whereas the other component was blocked slowly. The component blocked slowly was reduced but not eliminated by preexposure to 200 nM or 1 microM omega-Aga-IVA.
mCD24, a glycoprotein transiently expressed by neurons, is an inhibitor of neurite outgrowth
Authors: Shewan D , Calaora V , Nielsen P , Cohen J , Rougon G , Moreau H
Published: April 2018

In the immune system, mCD24, the mouse homolog of the human glycosyl phosphatidylinositol-anchored glycoprotein CD24, may play a role in cell adhesion. In the nervous system, the function of mCD24 has not been determined, but its transient expression by neurons suggests that it may be involved in axon growth in development. Here we show that retinal ganglion cells (RGCs) and dorsal root ganglion (DRG) neurons express mCD24 in the developing but not adult mouse in vivo and in DRG neurons of the injured adult peripheral nervous system (PNS). In vitro, mCD24 was expressed by immature neurons and by a subpopulation of adult DRG neurons. To analyze the possible function of mCD24 in the nervous system, we prepared rat C6 glioma cells stably transfected or retrovirally infected with mCD24 cDNA. The cells did not exhibit changes in their adhesive properties or cell division rate after transfection or infection. When mCD24-expressing cells were used as monolayer substrates for culturing RGCs and DRG neurons, neurite outgrowth was inhibited, depending on neuronal age and on the relative levels of mCD24 in the monolayer. This inhibition, however, was not dependent on the expression of mCD24 by the neurons themselves, because DRG neurons of a mouse deleted of the mCD24 gene showed the same response. These results show that mCD24 interacts in a heterophilic manner with a developmentally regulated molecule expressed by neurons, and they suggest that in vivo, mCD24 may inhibit the further extension or collateral branching of axons in late embryonic development.
Complexity affects regional cerebral blood flow change during sequential finger movements
Authors: Sadato N , Campbell G , Ibanez V , Deiber M , Hallett M
Published: April 2018

Brain regions activated with complex sequential finger movements were localized by measuring regional cerebral blood flow (rCBF) with positron emission tomography. Whereas the total number and frequency of finger movements were kept constant, the complexity of auditory cued sequential finger movements of the right hand varied, with sequence length as the independent variable. In four conditions of differing complexity, the bilateral primary sensorimotor area, left ventral premotor cortex, posterior supplementary motor area, right superior part of the cerebellum, and left putamen were consistently and equally activated. This finding suggests an executive role in running sequences, regardless of their length. The right dorsal premotor cortex (Brodmann area 6) and the right precuneus (Brodmann area 7) showed a linear increase of rCBF as sequence complexity increased. This finding is consistent with the hypothesis that these areas function in the storage of motor sequences in spatial working memory and the production of ongoing sequential movement with reference to that of buffered memory. A similar increase in the cerebellar vermis and the left thalamus likewise suggests a role of these subcortical structures in complexity of sequential finger movements. Conversely, the left inferior parietal lobule showed a decrease of rCBF as complexity increased. Because short-term phonological storage is localized to this area, we suggest that the visuospatial working memory system may suppress other systems not in use. Our findings suggest that complex sequential finger movements recruit a discrete set of brain areas, in addition to areas underlying the execution of simple movement sequences.
Physiological and morphological identification of somatostatin- or vasoactive intestinal polypeptide-containing cells among GABAergic cell subtypes in rat frontal cortex
Authors: Kawaguchi Y , Kubota Y
Published: April 2018

Physiological and morphological characteristics of GABAergic nonpyramidal cells in frontal cortex of young rats identified immunohistochemically as containing somatostatin or vasoactive intestinal polypeptide (VIP) were studied in vitro by whole-cell recording and biocytin injection. We have found that most somatostatin- or VIP-containing neurons were different from two other types of GABAergic cells, the parvalbumin-containing fast-spiking cells and the late-spiking cells (neurogliaform cells). In response to injected currents, somatostatin- or VIP-containing nonpyramidal cells showed either bursts of a few spikes on a slow-depolarizing hump, burst- spiking nonpyramidal cells, or single spikes only on depolarization, regular-spiking nonpyramidal cells. Morphologically, both somatostatin- and VIP-containing cells had vertical axonal arbors terminating in symmetrical synapses that were immunoreactive for GABA in electron micrographs. Somatostatin cells included neurons with main ascending axons sending collaterals into layer I (Martinotti cells in deep layers). Some of the Martinotti cells in layer V also contained calbindin D 28k. VIP cells included neurons the main descending axons of which had more descending than ascending collaterals (bipolar cells and double bouquet cells). Two other morphological forms of the VIP cells were those with short descending axons with collaterals bearing multiple boutons on other cell bodies (small basket cells) or with short ascending main axons with collaterals forming arcades (arcade cells). Some of these neurons also contained calretinin. From these results, it appears that the GABAergic neurons controlling circuits in the neocortical layers may be characterized further based on whether they contain somatostatin or VIP.
Abnormal tactile experience early in life disrupts active touch
Authors: Carvell GE , Simons DJ
Published: April 2018

The importance of early tactile experience in the development of discriminative somatomotor function was assessed by examining the proficiency and movement strategies of rats raised without normal sensory inputs provided by their mystacial vibrissae. Infant-trimmed animals had their whiskers clipped daily from birth to 45 d of age, after which they were allowed to regrow for 60–70 d before initiation of behavioral training, which lasted as long as several months. Adult- trimmed animals had their whiskers trimmed for comparable periods during adulthood. Rats were tested on one of two tactile discriminations, rough versus smooth or rough versus rough, that differed with respect to the overall size of their surface features. Whisker movements during task performance were examined in detail using video-based motion analysis software. Infant-trimmed animals performed rough versus smooth discriminations as well as adult-trimmed rats or normally reared animals. Except for one subject, infant-trimmed rats were severely impaired in their ability to distinguish rough versus rough surfaces. Deficits persisted in spite of months of training with the regrown vibrissae. The animals that failed to master this task displayed whisking patterns that notably lacked frequencies in the normal range of 6–12 Hz. Thus, abnormal tactile experience early in life substantially, and perhaps permanently, impairs sensorimotor integration underlying active touch.
Spatiotemporal properties of short-term plasticity sensorimotor thalamocortical pathways of the rat
Authors: Castro-Alamancos MA , Connors BW
Published: April 2018

Each region of neocortex receives synaptic input from several thalamic nuclei, but the response properties of thalamocortical pathways may differ. We have studied the frontoparietal (motor and somatosensory) neocortex of the rat and have examined the responses induced by stimulating two convergent thalamocortical projections originating in the ventrolateral (VL) nucleus and ventroposterior lateral (VPL) nucleus. Depth recordings and current-source density (CSD) analysis revealed two primary responses with different laminar and temporal patterns when VL and VPL were stimulated. Single shocks to VL produced a characteristic small current sink in layer V, which strongly enhanced in response to a second pulse delivered within a 50–200 msec interval (i.e., the augmenting response). In contrast, a shock to VPL evoked a large current sink that originated in layer IV, spread strongly into the supragranular layers, and was almost abolished in response to a second pulse at intervals of <200 msec (i.e., the decremental response). Control experiments determined that these responses could not be attributed to the antidromic firing of corticothalamic cells, intrathalamic mechanisms, or anesthesia. Topographic response maps were obtained from a grid of 30 sites across frontoparietal cortex. One shock to VL excited a very limited cortical region, but an augmenting response evoked 50–200 msec later spread at approximately 1 m/sec to synchronize the activity across an area up to 25 times larger. In contrast, a single shock to VPL activated a relatively large area, but the area activated by a second shock delivered within 200 msec was much smaller. We conclude that overlapping thalamocortical projections, originating in different thalamic nuclei, have distinct spatiotemporal response characteristics that may serve the functional specializations of these pathways.