bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Minimum Variance Distortionless Response Beamforming Algorithm Based Circular Antenna Arrays
Authors: Shahab Suhail Najm , Zainun Ayib Rosdi , S. Balasim S. , Noordin Nurul Hazlina , Mohamed Izzeldin Ibrahim
Published: September 2016

Wireless data traffic is in a continuous growth, and there are increasing demands for wireless systems that provide deep interference suppression and noise mitigation. In this paper, adaptive beamforming (ABF) technique for Smart Antenna System (SAS) based on Minimum Variance Distortionless Response (MVDR) algorithm connected toCircular Antenna Array (CAA) is discussed and analyzed. The MVDR performance is evaluated by varying various parameters; namely the number of antenna elements, space separation between the elements, the number of interference sources, noise power label, and a number of snapshots. LTE networks allocate a spectrum band of 2.6 GHz is used for evaluating the MVDR performance. The MVDR performance is evaluated with two important metrics; beampattern and SINR. Simulation results demonstrate that as the antenna elements increase, the performance of the MVDR improves dramatically. This means the performance of MVDR greatly relies upon the number of the elements. Half of the wavelength is considered the best interelement spacing, the performance degraded as noise power increased, and more accurately resolution occurred when the number of snapshots increased. The proposed method was found to be performed better than some existing techniques. According to the result, the beampattern relies on the number of element and the separation between array elements. Also, the SINR strongly depends on noise power label and the number of snapshots.
Analysis of travel behaviour in Petaling Jaya, Malaysia: an application of the theory of planned behaviour
Authors: Madha Ahmed , Salman Ali Dawod , Hussain Hussein Dhafir , Borhan Nazri , Rahmat Riza Atiq O.K.
Published: September 2016

In order to understand travellers’ willingness to use the train in Petaling Jaya, this study adds four predictors - situational factors, trust, novelty seeking and external influence - to the existing model of theory of planned behaviour (TPB). The study collected research data from employees in Petaling Jaya, Malaysia, resulting in valuable data of 400 participants. Results indicate that attitude, perceived behavioural control, and subjective norm are found to have positive effects on the behavioural intention of taking the train. Furthermore, novelty seeking and external influence also have positive influences on attitude. While the three antecedents of trust were found to have an indirect positive effect on commuters’ intention to take the train via attitude, subjective norm and PBC. Situational factors were found to have an indirect negative significant influence on people’s intention to take the train through perceived behavioural control.
Computer-aided model construction and database design of railway yard information
Authors: Tang Yuanxiang , Zhang Wencai
Published: September 2016

Railway yard is the basic composition unit of railways, therefore, the efficiency and quality of railway yard design have a crucial effect on the construction and operation of railways. Plane design is the basis and core of railway yard design, consequently, it is significant to research plane design of railway yard. In this study, through analysis and summary of the research status as well as integrated application of computer technology and railway yard plane design methods, we researched and developed railway yard plane design system based on AutoCAD platform. According to the characteristics of railway yard plane design, we constructed the information model based on which we established specialized database, with the information data organized and managed efficiently; moreover, we put forward methods of constructing geometric models of the plane equipment, meanwhile, we did a focused research on associated design of yard equipment and preliminarily realized linkage design of planar yards.
Determination of Lutein and Zeaxanthin Esters and Their Geometric Isomers in Carotenoid Ester Concentrates Used as Ingredients in Nutritional Supplements: Validation of a Combined Spectrophotometric-HPLC Method
Authors: Lombeida Wagner O , Rubio Fernando , Levy Luis W
Published: September 2016

A combined spectrophotometric-LC method is described for the determination of total lutein and zeaxanthin ester content in carotenoid ester concentrates, including their main geometrical isomers. The concept of composite-specific absorbance is introduced for this purpose. The method is applicable to carotenoid ester concentrates used as ingredients in oil suspensions and dosage forms. The sample is dissolved in a hexane–2-propanol mixture (95 + 5, v/v) for spectrophotometric measurement at a maximum absorption of ~445 nm. Subsequently, in parallel, a sample is saponified and chromatographed on a normal-phase HPLC column to determine the relative percentage profile of the main geometrical isomers of both carotenoid esters. This, in turn, is used to calculate the composite-specific absorbance of the sample for the final calculation of results. The method, which solely uses reference standards to validate chromatographic conditions, avoids the common error of applying the specific absorbance of only the trans isomer for the calculation of total carotenoid content when cis isomers are present.
Vitamin C in Infant Formula and Adult/Pediatric Nutritional Formula by Liquid Chromatography with UV Detection: Collaborative Study, Final Action 2012.22
Authors: Giménez Esther Campos , Martin Frédéric ,   Collaborators:, Schimpf K , Butler Thompson L , Aoude-Werner D , Grandois J Dalmas-Le , Wong J , Chia J , Malaviole I , Mapar M , Nguyen T , Hoard M , Joseph G , Ma L , Wu B , Rogers T , Austad J , Jensen B M , Pedersen I , Jensen S Meng , Zhang Y , Jobgen W , Weihong C , Xiuying L , Chanyuan H , Woollard D , Kneeteman E , Hernández O Hernández , Beltrán E , Weerasekera G , Frueh J , González P , Román E , Carreño M , Jaudzems G , Nijman R , Noorloos T , Yap L K , Chooi S H , Lautenschlager G J , Christiansen S , Piot D , Barba Le Brun M
Published: September 2016

To determine the repeatability and reproducibility values of the AOAC INTERNATIONAL First Action Method 2012.22, Vitamin C in Infant Formula and Adult/Pediatric Nutritional Formula by Liquid Chromatography with UV Detection, a collaborative study was organized The study was dividedinto two parts: method setup and qualification of participants (part 1) and collaborative study participation (part 2). During part 1, each laboratory was asked to analyze two practice samples using the aforementioned method Laboratories that provided results within a range of expected levels were qualified for part 2, where they analyzed 10 samples in blind duplicates Two of the samples were suspected of spoilage during the test and new cans of the same type of product were analyzed by a subset of laboratories in part 3. The results were compared with Standard Method Performance Requirement (SMPR®) 2012.012 established for vitamin C The precision results were within the requirements stated in the SMPR: 1.4–7.3% and 3.2–11.4% respectively, for repeatability and reproducibility Finally, Horwitz ratio values were all <2 (0.5–1.7). The Expert Review Panel for Stakeholder Panel for Infant Formula and Adult Nutritionals Nutrient Methods determined that the data presented met the SMPR and therefore recommended the method be granted Final Action status.
A correlação do desenvolvimento do campo com o desenvolvimento da cidade de Canguçu – RS
Authors: Bandeira Silvana De Matos
Published: September 2016

Resumo: O trabalho visa pesquisar a causa do desenvolvimento do comércio da área central de Canguçu (RS) no período 2000-2010. Inicialmente foi realizada uma revisão bibliográfica sobre os conceitos abordados. Utilizando-se do método progressivo-regressivo de Henri Lefèbvre, a história de Canguçu foi dividida em periodizações de acordo com as suas fases econômicas. Por fim, foram realizadas entrevistas com comerciantes e representantes de entidades, a fim de que estes pudessem se manifestar sobre a importância da fumicultura para o município. Partiu-se da hipótese que o crescimento significativo do comércio foi causado pelo aumento da fumicultura no município, o que gerou renda e, consequentemente, dinamizou o comércio. Esta hipótese se confirmou no decorrer do trabalho.   Palavras-chave: Canguçu. Comércio. Fumicultura. Dependência econômica.
Educação ambiental no ensino fundamental II: o lugar que temos o lugar que queremos
Authors: Silva Claudionor Oliveira , Ximenes Lilian Carla de Lima , Oliveira Maria Helena Cardoso de
Published: September 2016

Resumo: O presente trabalho tem como objetivo principal analisar o Ensino da Educação Ambiental nas Séries do Fundamental II da Escola Joaquim Gomes de Araújo, na comunidade Várzea Grande em União dos Palmares. A metodologia usada foi baseada em pesquisas bibliográficas, documentais e de campo, assim como registros de imagem, entrevistas, observações, relato de experência e aplicação de questionários socioambientais aos alunos, professores e a comunidade local. Os resultados mostram a análise sobre o Projeto O Lugar que Temos: O Lugar que Queremos desenvolvido pela instituição, as práticas pedagógicas desenvolvidas pelos docentes e discentes em EA, e a participação da comunidade no projeto pedagógico e  os problemas ambientais existentes no povoado.Palavras-chave: Educação Ambiental. Ambiente Escolar. Conscientização. Impactos Ambientais.
Aplicação de dados SRTM para a caracterização de microbacias hidrográficas urbanas
Authors: Bariani Cassiane Jrayj de Melo Victoria , Bariani Nelson Mario Victoria
Published: September 2016

Dados SRTM foram utilizados para a análise comparativa de duas microbacias urbanas em Itaqui, RS, visando identificar fatores de impacto para fins de planejamento. Os limites das microbacias e os canais da rede de drenagem foram traçados combinando o uso de um algoritmo automático de detecção de fluxo e a edição vetorial de imagens de satélite (CBERS 2B/HRC) no SPRING.  Os parâmetros morfométricos foram calculados com informações obtidas por “medidas de classe”. A microbacia do Olaria apresentou valores de fator de forma, coeficiente de compacidade, ordem e sinuosidade com características que favorecem o escoamento das águas.  Há uma maior tendência a enchente na microbacia do Cambaí, verificado em imagens dos satélites Landsat 5 e 8 em épocas de enchente.
Fotografia e Propaganda nas Práticas de Ensino em Aulas de Geografia
Authors: Pfluck Lia Dorotéa
Published: September 2016

Nesse artigo se trazem reflexões sobre a importância do uso de imagens no processo de ensino-aprendizagem de Geografia. A fotografia e a propaganda, com seus inúmeros encantos, significados ou simulacros, abrem um universo de possibilidades geográficas a serem trabalhadas e relacionadas ao dia a dia do professor e dos alunos. As imagens usadas são fragmentos do contexto histórico-geográfico do Oeste do Paraná, em especial do município de Marechal Cândido Rondon, década de 1950. As ações e práticas se desenvolveram durante as aulas da disciplina de Estágio Supervisionado III (Prática de Ensino em Geografia III), do Curso de Geografia, da Universidade Estadual do Oeste do Paraná (Unioeste), em 2013. A partir dos conhecimentos prévios dos alunos e do meio geográfico no qual eles estão inseridos (município e Oeste do Paraná) foi possível alcançar uma aprendizagem significativa e transitar por conteúdos aplicáveis ao Ensino Médio. As linguagens serviram como apoio para as aulas da disciplina e potencializaram a análise e o conhecimento do espaço geográfico, relacionadas aos conceitos e aos eixos temáticos do Ensino Médio de Geografia onde o Estágio Supervisionado é aplicado. É que as imagens usadas possibilitaram investigações e descobertas, sistematizações de informações, estabelecimento de métodos para analisar seus conteúdos e, sobretudo, tornaram o ensino mais prazeroso.
O método materialista-histórico-dialético e a relação com a diretriz curricular orientadora de Geografia do Paraná
Authors: Opolski Carolina Albertoni , Leme Rosana Cristina Biral
Published: September 2016

Resumo: Neste artigo fazemos uma reflexão sobre o método materialista histórico dialético analisando sobre as bases teóricas que possibilitam uma interpretação da realidade e refletem na sociedade demonstrando seu movimento e as contradições existentes. Consideramos importante os fundamentos teóricos do método e o que provém desta base teórica. Esta linha teórica na área pedagógica desenvolveu a Linha Crítica do pensamento que analisa a realidade em conformidade com as ideias do materialismo histórico dialético. No estado do Paraná a partir de 2003 foi pensada e elaborada uma diretriz curricular baseada nessa perspectiva, diante disso faremos uma relação entre o método e a diretriz curricular elaborada no estado e que fundamenta teoricamente a prática pedagógica, como uma contribuição teórica e a relação com o método.
O ensino de Geografia em uma escola do campo e uma escola da cidade no município de Agudo-RS: características e diversidades
Authors: Schirmer Gerson Jonas , Cardoso Eduardo Schiavone , Dal' Ongaro Marisa
Published: September 2016

A localização geográfica da escola, pode assumir um papel de destaque na formação escolar, sendo esta muitas vezes o elo entre o que o aluno vivencia no seu cotidiano e o que este aprende dentro da sala de aula. O presente estudo tem como objetivo apresentar uma análise da rede de ensino e do ensino de geografia no município de Agudo, localizado na Região Central do estado do Rio Grande do Sul. Para tanto fez-se uma caracterização geral da rede de ensino do Município, pesquisou-se as características específicas de  uma escola do campo e de uma escola da cidade, bem como a sua contribuição na compreensão e valorização do lugar.  Constatou-se que apesar dos esforços por parte de alguns professores, embasado nos procedimentos adotados, a escola segue formando sujeitos sociais que não estabelecem uma verdadeira identidade com o lugar.
A importância dos sistemas geodésicos de referência no cadastramento rural
Authors: Rubira Felipe Gomes , Melo Georgea Do Vale de , Fonseca Gustavo
Published: September 2016

O objetivo desta pesquisa consiste em discutir as principais ações envolvendo os SGR para o cadastramento de imóveis rurais por meio da lei nº 10.267/01 que determinou a criação de um cadastro imobiliário rural obrigatório. A metodologia empregada baseou-se em reflexões teóricas através de pesquisa bibliográfica. Os resultados evidenciaram a importância dos Sistemas de Referências Brasileiros para o desmembramento, parcelamento ou remembramento de imóveis rurais. Concluiu-se que os sistemas geodésicos são imprescindíveis para o pleno sucesso de cadastramento e mapeamento dos limites territoriais de imóveis rurais, com eles foram evitados vários problemas como sobreposição de áreas, grilagem de terras e a formação ilegal de latifúndios no Brasil, coibindo a apropriação irregular e a transferência fraudulenta de terras. Concluiu-se que a mudança de um sistema de origem topocêntrica (Córrego Alegre e SAD 69) para geocêntrica (SIRGAS 2000) trouxe uma série de benefícios e vantagens.
Rook-drawings of Plane Graphs
Authors: Auber David , Bonichon Nicolas , Dorbec Paul , Pennarun Claire
Published: September 2016

We introduce a new type of graph drawing called "rook-drawing".
A rook-drawing of a graph $G$ is obtained by placing the $n$ nodes of $G$ on the intersections of a regular grid, such that each row and column of the grid supports exactly one node.
This paper focuses on rook-drawings of planar graphs.
We first give a linear algorithm to compute a planar straight-line rook-drawing for outerplanar graphs.
We then characterize the maximal planar graphs admitting a planar straight-line rook-drawing, which are unique for a given order.
Finally, we give a linear time algorithm to compute a polyline planar rook-drawing for plane graphs with at most $n-3$ bent edges.
Mort et disparition durant la dernière dictature militaire argentine (1976-1983) : les « disparus » et les soldats tombés lors de la Guerre des Malouines
Authors: Panizo Laura Marina , Verstraeten Alice
Published: September 2016

Dans cet article, je propose une synthèse des résultats de mes recherches sur la problématique de la mort violente et de l’absence de corps qui, dans le contexte de la dernière dictature militaire argentine, ne concerne pas seulement les victimes de la répression étatique mais touche également les soldats tombés pendant la Guerre des Malouines. Je tente de rendre compte de la façon dont deux groupes de proches se sont constitués à partir de la mort et de la disparition d’êtres chers, et ont élaboré des cadres d’interprétation pour donner du sens aux événements historiques survenus, afin de surmonter leurs pertes. Ces cadres d’interprétation, les pratiques quotidiennes et les croyances relatives à la mort se rétro-alimentent ; se construisent alors des liens spécifiques entre vivants et morts.
La disparition et l’affaire des quarante-trois étudiants de l’École Normale rurale d’Ayotzinapa
Authors: Gil Irene Ramos
Published: September 2016

Cet article se propose d’analyser la manière dont la disparition de quarante-trois étudiants de l’École Normale rurale d’Ayotzinapa est devenue une affaire. Autrement dit, il s’agit de s’interroger sur la manière dont des revendications locales ont pu émerger et monter en généralité pour accéder à la sphère publique, comme celles des mobilisations collectives au Mexique et ailleurs. Nous essayerons de répondre en observant l’événement durant les jours qui ont suivi cette disparition. Deux sources principales sont consultées : les comptes rendus judicaires et les récits des victimes. L’analyse des descriptions et catégorisations élaborées par les personnes et institutions concernées s’avère donc nécessaire pour avoir accès aux différentes compréhensions internes à cette affaire.
Étalement urbain et dynamique des agglomérations à Alger : quel rôle pour la promotion administrative ?
Authors: Bakour Mohammed , Baouni Tahar
Published: September 2016

Devant les disparités spatiales auxquelles étaient confrontées les villes algériennes après l’indépendance, l’État a tenté de faire face à la situation en reconsidérant le maillage territorial par quatre découpages administratifs successifs (1963, 1974, 1984 et 1997). Nous proposons, dans cet article, d’analyser les conséquences spatiales de ces politiques publiques sur le processus de développement de l’agglomération algéroise. Une réflexion profonde sur l’évolution des agglomérations à Alger (changement de statut, émergence de nouvelles agglomérations, fusion entre les agglomérations chefs-lieux et les agglomérations secondaires, etc.) nous semble une approche très intéressante. Cela, d’un côté, pour avoir une vision claire du processus d’étalement urbain et, d’un autre côté, pour mieux apprécier l’évolution morphologique à laquelle est confrontée la ville d’Alger. Dans l’article, nous analysons la dynamique des agglomérations qui a accompagné le découpage administratif à Alger. Il s’agit de donner un éclairage nouveau sur le rôle qu’ont joué l’évolution et le changement de statut des agglomérations ainsi que la promotion administrative,1 pour mieux apprécier l’évolution morphologique qu’a connue la ville d’Alger. À travers la mise en place d’une base de données sous SIG et par une approche historique et comparative, le résultat de ce travail nous a permis une meilleure lecture spatiotemporelle des mutations qu’ont subies les différentes agglomérations à Alger, de 1966 à ce jour. En effet, cette approche n’a jamais fait l’objet d’une analyse profonde dans le cadre des différentes recherches sur la ville d’Alger.
L’éclosion coopérative en pays bamiléké – Cameroun (1930-2010)
Authors: Noumen Robert
Published: September 2016

L’espace géographique dans lequel agissent les instruments de la coopérative importée en pays bamiléké est pour l’essentiel représenté par la province de l’Ouest, dans l’actuelle division administrative du Cameroun. La greffe de ce modèle importé dans la région se juxtapose aux structures des réseaux de la solidarité traditionnelle. Cette juxtaposition va favoriser un fonctionnement en décalage avec les codes habituels associés à la réalité concrète. Elle nécessitera, pour survivre par la suite, une double mutation intégrée au sein du même corps sociétal en réalisant, d’une part, le passage de la solidarité à la rentabilité et, d’autre part, le passage de la communauté à l’organisation.
Mechanism for nuclease regulation in RecBCD
Authors: Wilkinson Martin , Chaban Yuriy , Wigley Dale B
Published: September 2016

In bacterial cells, processing of double-stranded DNA breaks for repair by homologous recombination is catalysed by AddAB, AdnAB or RecBCD-type helicase-nucleases. These enzyme complexes are highly processive, duplex unwinding and degrading machines that require tight regulation. Here, we report the structure of E.coli RecBCD, determined by cryoEM at 3.8 Å resolution, with a DNA substrate that reveals how the nuclease activity of the complex is activated once unwinding progresses. Extension of the 5’-tail of the unwound duplex induces a large conformational change in the RecD subunit, that is transferred through the RecC subunit to activate the nuclease domain of the RecB subunit. The process involves a SH3 domain that binds to a region of the RecB subunit in a binding mode that is distinct from others observed previously in SH3 domains and, to our knowledge, this is the first example of peptide-binding of an SH3 domain in a bacterial system.
Interface acoustic waves at the interface between two semi-infinite phononic crystals
Authors: Tanaka Yukihiro , Okashiwa Nobuharu , Nishiguchi Norihiko
Published: September 2016

We have investigated the band structures of interface acoustic waves (IAWs) in a system composed of two dissimilar semi-infinite two-dimensional (2D) phononic crystals (PCs), which is referred to as a dual 2D PC system. We suggest a method by which we can estimate roughly the constituent elements (for example, filling fraction and type of substance) of each PC in a dual 2D PC system. We find that, for a specific set of filling fractions of the constituent PCs, an IAW branch exists below the lowest bulk transverse-wave branch in dispersion relations, and is subject to Bragg reflection in the vicinity of the Brillouin-zone boundary, which reduces the group velocity of IAWs. The findings of this work suggest the possibility of new acoustic devices utilizing IAWs.
Lateral growth of GaN by liquid phase electroepitaxy using mesa-shaped substrate
Authors: Kambayashi Daisuke , Takakura Hiroyuki , Tomita Masafumi , Iwakawa Muneki , Mizuno Yosuke , Maruyama Takahiro , Naritsuka Shigeya
Published: September 2016

GaN microchannel epitaxy (MCE) was performed using a mesa-shaped substrate and liquid phase electroepitaxy. A flat and wide MCE layer was successfully obtained with a rectangular shape, which is formed by ±c-planes on both the top and bottom surfaces. MCE growth proceeded mainly in the lateral direction by the formation of these planes. Cathodoluminescence measurements showed that the laterally grown layers were almost free of dislocations, and that the dislocations in the mesa areas were confined by the vertical sides of the mesas. In the case of inclined sides, the dislocations would be expected to bend and spread into the laterally grown areas.
Domain switching kinetics in vinylidene fluoride/tetrafluoroethylene copolymer thin films
Authors: Nakagawa Yuuta , Hashizume Yoichiro , Nakajima Takashi , Gruverman Alexei , Okamura Soichiro
Published: September 2016

The local domain switching of vinylidene fluoride/tetrafluoroethylene copolymer thin films with different higher order structures was investigated by piezoresponse force microscopy. It was found that one-dimensionally grown domains were formed on highly crystallized needle-like crystals after local voltage pulse application. This is because each needle-like crystal consisted of parallel-stacked lamellae with chain folding along its major axis. In addition, it showed two-step domain growth processes, namely, inter lamella domain growth and the growth between lamellae. On the other hand, circular domains were formed on polycrystalline plate-like crystals and as-coated films.
Enhanced polarization properties of ferrielectric AgNbO3 single crystals grown by Czochralski method under high-pressure oxygen atmosphere
Authors: Kitanaka Yuuki , Egawa Takuya , Noguchi Yuji , Miyayama Masaru
Published: September 2016

We report crystal growth under high oxygen pressure (P
O2) atmosphere that yields high-quality single crystals of AgNbO3. X-ray fluorescence analysis reveals that an increase in P
O2 during crystal growth effectively suppresses the deficiency of Ag and then leads to low leakage currents. Single crystals grown via the Czochralski method at a P
O2 of 0.9 MPa are demonstrated to show ferrielectric switching with enhanced polarization under electric fields along the [110] direction.
Prostate Cancer Screening in Men of African Descent: 15-year Results of the Tobago Prostate Cancer Survey
Authors: Patrick AL , Nelson JB , Weissfeld JL , Dhir R , Phillips RJ , Zmuda JM , Bunker CH
Published: September 2016

Objective: To compare all-cause-mortality in screening-detected prostate cancer cases versus non-cases after a median 12.2-year follow-up. Methods: In this prospective, population-based study of 3089 Afro-Caribbean men aged 40–79 years in Tobago, Trinidad and Tobago, West Indies, all men were screened for prostate cancer (serum prostate specific antigen and/or digital rectal exam) one to three times between 1997
and 2007 and followed for mortality to 2012. Among 502 men diagnosed with prostate cancer, 81 younger men underwent radical retropubic prostatectomy. Minimal treatment was available for older men. Survival curves compared all-cause-mortality in cases versus non-cases within 10-year age groups at first screening. Results: There were 350 all-cause-deaths over 34 089 person-years of follow-up. All-cause-survival
curves in men aged 60 years or above at first screening did not diverge between cases
and non-cases until after 10–12 years of follow-up (p > 0.36). In contrast, among men first screened at age 50–59 years, survival was lower in cases, with survival curves diverging at seven years (p = 0.003). Survival in men aged 50–59 years who underwent prostatectomy was similar to survival in non-cases (p = 0.63). Conclusion: Among men aged 60 years or above, the absence of excess all-cause-mortality among screening-detected prostate cancer cases provides argument against the utility of routine prostate cancer screening in this older population of African descent. However, the significantly poorer survival in men aged 50–59 years with screening-detected prostate cancer, compared with screened men without prostate cancer, along with the potential for prostate cancer treatment to improve survival, supports the continuation of prostate cancer screening in this age group, pending further research to assess the risks and benefits.
Scale‐dependent distribution of kinetic energy from surface drifters in the Gulf of Mexico
Authors: Balwada Dhruv , LaCasce Joseph H. , Speer Kevin G.
Published: September 2016

The scale‐dependent distribution of kinetic energy is probed at the surface in the Gulf of Mexico using surface drifters from the Grand Lagrangian Deployment (GLAD) experiment. The second‐order velocity structure function and its decomposition into rotational and divergent components are examined. The results reveal that the divergent component, compared to the rotational component, dominates at scales below 5 km, and the pattern is reversed at larger scales. The divergent component has a slope near 2/3 below 5 km, similar to an energy cascade range (k−5/3). The third‐order velocity structure function at scales below 5 km is negative and implies a forward cascade of energy to smaller scales. The rotational component has a steeper slope, roughly 1.5, from scales of 5 km up to the deformation radius. This is similar to a 2‐D enstrophy cascade, although the slope is shallower than the predicted 2. There is a brief 2/3 range from the deformation radius to 200 km, suggestive of a 2‐D inverse cascade.
Diabatic heating and jet stream shifts: A case study of the 2010 negative North Atlantic Oscillation winter
Authors: Woollings Tim , Papritz Lukas , Mbengue Cheikh , Spengler Thomas
Published: September 2016

The role of extratropical diabatic heating in the variability of storm tracks and jet streams remains an important open question. This paper analyzes the role of diabatic heating in observationally constrained analysis data for the 2010 winter, which was notable for an extreme southward shift of the North Atlantic eddy‐driven jet. An isentropic slope framework is employed by which the contribution of diabatic terms to the maintenance of seasonal mean baroclinicity can be quantified. This reveals a striking contrast between the eastern North Atlantic, where the latent heating shifted south along with the storm track in 2010, and the western North Atlantic, where the latent heating remained fixed over the Gulf Stream. This motivates the hypothesis that the latent heating may contribute to the anchoring of the storm track entrance over the Gulf Stream but provide a very different feedback on the jet variability downstream.
Spatial coherence of the seismic wavefield continuously recorded by the USArray
Authors: Seydoux L. , Shapiro N. M. , de Rosny J. , Landès M.
Published: September 2016

We use a method based on the array covariance matrix eigenvalues to study the level of spatial coherence and of isotropy of the seismic wavefield continuously recorded during 2010 by the USArray. First, we observe that the raw data are often dominated by local sources. To remove their influence, we apply spectral and temporal normalizations to the input signals. We notice that this widely used preprocessing in ambient‐noise seismology does not fully homogenize the seismic wavefield and that some strongly coherent arrivals persist. Among these persistent signals generated by teleseismic sources we detect (1) seismic waves emitted by strong earthquakes, (2) a nearly continuous quasi‐monochromatic signal at 26 s period, and (3) multiday coherent wave trends in the spectral band of oceanic microseisms (0.07–0.2 Hz). For the latter, beamforming analysis shows that while most of the signals are composed of surface waves, some are dominated by body waves likely generated in the deep ocean.
An integral field spectrograph utilizing mirrorlet arrays
Authors: Chamberlin Phillip C. , Gong Qian
Published: September 2016

An integral field spectrograph (IFS) has been developed that utilizes a new and novel optical design to observe two spatial dimensions simultaneously with one spectral dimension. This design employs an optical 2‐D array of reflecting and focusing mirrorlets. This mirrorlet array is placed at the imaging plane of the front‐end telescope to generate a 2‐D array of tiny spots replacing what would be the slit in a traditional slit spectrometer design. After the mirrorlet in the optical path, a grating on a concave mirror surface will image the spot array and provide high‐resolution spectrum for each spatial element at the same time; therefore, the IFS simultaneously obtains the 3‐D data cube of two spatial and one spectral dimensions. The new mirrorlet technology is currently in‐house and undergoing laboratory testing at NASA Goddard Space Flight Center. Section 1 describes traditional classes of instruments that are used in Heliophysics missions and a quick introduction to the new IFS design. Section 2 discusses the details of the most generic mirrorlet IFS, while section 3 presents test results of a lab‐based instrument. An example application to a Heliophysics mission to study solar eruptive events in extreme ultraviolet wavelengths is presented in section 4 that has high spatial resolution (0.5 arc sec pixels) in the two spatial dimensions and high spectral resolution (66 mÅ) across a 15 Å spectral window. Section 4 also concludes with some other optical variations that could be employed on the more basic IFS for further capabilities of this type of instrument.
The parameterization of microchannel‐plate‐based detection systems
Authors: Gershman Daniel J. , Gliese Ulrik , Dorelli John C. , Avanov Levon A. , Barrie Alexander C. , Chornay Dennis J. , MacDonald Elizabeth A. , Holland Matthew P. , Giles Barbara L. , Pollock Craig J.
Published: September 2016

The most common instrument for low‐energy plasmas consists of a top‐hat electrostatic analyzer (ESA) geometry coupled with a microchannel‐plate‐based (MCP‐based) detection system. While the electrostatic optics for such sensors are readily simulated and parameterized during the laboratory calibration process, the detection system is often less well characterized. Here we develop a comprehensive mathematical description of particle detection systems. As a function of instrument azimuthal angle, we parameterize (1) particle scattering within the ESA and at the surface of the MCP, (2) the probability distribution of MCP gain for an incident particle, (3) electron charge cloud spreading between the MCP and anode board, and (4) capacitive coupling between adjacent discrete anodes. Using the Dual Electron Spectrometers on the Fast Plasma Investigation on NASA's Magnetospheric Multiscale mission as an example, we demonstrate a method for extracting these fundamental detection system parameters from laboratory calibration. We further show that parameters that will evolve in flight, namely, MCP gain, can be determined through application of this model to specifically tailored in‐flight calibration activities. This methodology provides a robust characterization of sensor suite performance throughout mission lifetime. The model developed in this work is not only applicable to existing sensors but also can be used as an analytical design tool for future particle instrumentation.
Where does the plasmasphere begin? Revisit to topside ionospheric profiles in comparison with plasmaspheric TEC from Jason‐1
Authors: Lee Han‐Byul , Kim Yong Ha , Kim Eunsol , Hong Junseok , Kwak Young‐Sil
Published: September 2016

Topside ionospheric profiles have been measured by Alouette 1 and ISIS 1/2 in the periods of 1962–1972 and 1972–1979, respectively. The profiles cover from the orbital altitude of 1000 km to the F2 peak and show large variations over local time, latitude, and seasons. We here analyze these variations in comparison with plasmaspheric total electron contents (pTECs) that were measured by Jason‐1 satellite from the altitude of 1336 km to 20,200 km (GPS orbit). The scale heights of the profiles are generally smaller in the daytime than nighttime but show large day‐to‐day variations, implying that the ionospheric profiles at 1000 km are changing dynamically, rather than being in diffusive equilibrium. We also derived transition heights between O+ and H+, which show a clear minimum at dawn for low‐latitude profiles due to decreasing O+ density at night. To compare with pTEC, we compute topside ionospheric total electron content (tiTEC) by integrating over 800–1336 km using the slope of the profiles. The tiTEC varies in a clear diurnal pattern from ~0.3 to ~1 and ~3 total electron content unit (TECU, 1 TECU = 1016 el m−2) for low and high solar activity, respectively, whereas Jason‐1 pTEC values are distributed over 2–6 TECU and 4–8 TECU for low and high solar activity, respectively, with no apparent diurnal modulation. Latitudinal variations of tiTEC show distinctive hemispheric asymmetry while that of Jason‐1 pTEC is closely symmetric about the magnetic equator. The local time and latitudinal variations of tiTEC basically resemble those of the ionosphere but are characteristically different from those of Jason‐1 pTEC. Based on the difference between tiTEC and pTEC variations, we propose that the region above ~1300 km should be considered as the plasmasphere. Lower altitudes for the base of “plasmaspheric TEC,” as used in some studies, would cause contamination of ionospheric influence.
Statistical characteristics of potentially chorus‐driven energetic electron precipitation from POES observations
Authors: Li Haimeng , Yuan Zhigang , Wang Dedong , Huang Shiyong , Qiao Zheng , Yu Xiongdong
Published: September 2016

In this paper, using the Polar Orbiting Environment Satellites (POES) in the year 2011, we present global distributions of energetic electron precipitation (EEP) events that may be driven by lower band chorus waves. Since the footprint of plasmapause in the ionospheric height can basically be equal to midlatitude trough minimum, it can be identified through the global total electron content map. Then we distinguish events perhaps driven by chorus waves outside the plasmapause or those driven by hiss waves inside the plasmapause. Based on the simultaneous observations of EEP in the E1 0° (>30 keV) and E2 0° (>100 keV) channels from POES satellites, a total of 4455 potentially chorus‐driven events are identified. The potentially chorus‐driven events are mainly distributed from midnight to noon which is similar to the distribution of lower band chorus waves. As the level of geomagnetic substorm activity increases, the occurrence rate is higher, which could be due to excitation of chorus waves associated with substorm electron injection. During higher level of substorm, a large number of events occur in lower L shells. Besides, since the magnetosphere on the dayside is compressed and strong chorus waves are limited to the region where the ratio between the plasma frequency and electron gyrofrequency is less than 5, under the strong substorm, the events on the nightside are confined to lower L shells due to smaller electron gyrofrequencies relative to those on the dayside. The occurrence rate of the events on the dayside also increases with enhancement of solar wind dynamic pressure, which suggests that the solar wind dynamic pressure can contribute to the excitation of events on the dayside. The statistics of potentially chorus‐driven events are helpful to analyze the distribution of lower band chorus waves and their contributions to the loss of energetic electrons in the inner magnetosphere.
Low‐latitude gravity wave variances in the mesosphere and lower thermosphere derived from SABER temperature observation and compared with model simulation of waves generated by deep tropical convection
Authors: Walterscheid R. L. , Christensen A. B.
Published: September 2016

A portion of waves generated by deep convection have scales and amplitudes large enough to be detected by spaceborne instruments. We have analyzed temperature data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) satellite for subtidal‐scale fluctuations. Filtering was applied both vertically and horizontally to extract wave variances. We have analyzed the altitude region between 70 and 130 km and focus on the variances at equatorial latitudes for the altitude region between 70 and 120 km as a function of season, local time intervals, geographical location, and altitude. We find significant variances where convection is particularly prolific (Intertropical Convergence Zone) and at altitudes where wave trapping is known to be favored (e.g., the lower thermospheric duct). The locations of significant variances persist from year to year. Standard deviations of a few tens of kelvins are found. We have also performed simulations of the response to deep tropical convection with a time‐dependent, high‐resolution fully compressible dynamical model. Our simulations give wave amplitudes that agree reasonably well with the observed amplitudes and show layering that is consistent with the observations. Our main finding is that significant variations seen in TIMED/SABER temperature data have a convective wave source and are concentrated in layers where thermal ducts occur.
Analysis of impact crater populations and the geochronology of planetary surfaces in the inner solar system
Authors: Fassett Caleb I.
Published: September 2016

Analyzing the density of impact craters on planetary surfaces is the only known technique for learning their ages remotely. As a result, crater statistics have been widely analyzed on the terrestrial planets, since the timing and rates of activity are critical to understanding geologic process and history. On the Moon, the samples obtained by the Apollo and Luna missions provide critical calibration points for cratering chronology. On Mercury, Venus, and Mars, there are no similarly firm anchors for cratering rates, but chronology models have been established by extrapolating from the lunar record or by estimating their impactor fluxes in other ways. This review provides a current perspective on crater population measurements and their chronological interpretation. Emphasis is placed on how ages derived from crater statistics may be contingent on assumptions that need to be considered critically. In addition, ages estimated from crater populations are somewhat different than ages from more familiar geochronology tools (e.g., radiometric dating). Resurfacing processes that remove craters from the observed population are particularly challenging to account for, since they can introduce geologic uncertainty into results or destroy information about the formation age of a surface. Regardless of these challenges, crater statistics measurements have resulted in successful predictions later verified by other techniques, including the age of the lunar maria, the existence of a period of heavy bombardment in the Moon's first billion years, and young volcanism on Mars.
Measuring spatiotemporal variation in snow optical grain size under a subalpine forest canopy using contact spectroscopy
Authors: Molotch Noah P. , Barnard David M. , Burns Sean P. , Painter Thomas H.
Published: September 2016

The distribution of forest cover exerts strong controls on the spatiotemporal distribution of snow accumulation and snowmelt. The physical processes that govern these controls are poorly understood given a lack of detailed measurements of snow states. In this study, we address one of many measurement gaps by using contact spectroscopy to measure snow optical grain size at high spatial resolution in trenches dug between tree boles in a subalpine forest. Trenches were collocated with continuous measurements of snow depth and vertical profiles of snow temperature and supplemented with manual measurements of snow temperature, geometric grain size, grain type, and density from trench walls. There was a distinct difference in snow optical grain size between winter and spring periods. In winter and early spring, when facetted snow crystal types were dominant, snow optical grain size was 6% larger in canopy gaps versus under canopy positions; a difference that was smaller than the measurement uncertainty. By midspring, the magnitude of snow optical grain size differences increased dramatically and patterns of snow optical grain size became highly directional with 34% larger snow grains in areas south versus north of trees. In winter, snow temperature gradients were up to 5–15°C m−1 greater under the canopy due to shallower snow accumulation. However, in canopy gaps, snow depths were greater in fall and early winter and therefore more significant kinetic growth metamorphism occurred relative to under canopy positions, resulting in larger snow grains in canopy gaps. Our findings illustrate the novelty of our method of measuring snow optical grain size, allowing for future studies to advance the understanding of how forest and meteorological conditions interact to impact snowpack evolution.
Aptamers
Authors: Gopinath Subash C.B.
Published: September 2016

Aptamer is an artificial nucleic acid ligand, the so‐called artificial antibody, can be generated in vitro from the synthetic nucleic acid library by the process called ‘systematic evolution of ligands by exponential enrichment’ (SELEX). This process involves iterative rounds complex formation, separation, and amplification. At the end of this process, predominant aptamer will be found and it has high affinity to the cognate target. There are several modifications that have been demonstrated in the selection process with the generation of high‐affinity aptamers. The aptamer undergoes proper folding to interact with their target and fulfil the desired function. The aptamer behaves similar to the antibody and in several instances attested to be better than antibody. The aptamer and antibody complementation has also been shown with high‐performance assays. Currently, several aptamers are undergoing different clinical phase trials toward their applications in theranostics.
Chromatography of Membrane Proteins and Lipoproteins
Authors: Zolla Lello , D'Alessandro Angelo , Lana Alessandro
Published: September 2016

The available methods for the separation of membrane proteins and lipoproteins are sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS/PAGE), followed by immunoblotting, isoelectric focusing (IEF), and capillary electrophoresis (CE), along with the recently introduced gel‐based native techniques (blue native (BN) and clear native (CN)), and high‐performance liquid chromatography (HPLC). In this article, it is shown that HPLC techniques, given their wide versatility, relative ease of use, and high resolution, may be considered the most valuable tool for the characterization of virtually any hydrophobic protein. Application examples are described, and comparisons with other methods are discussed. Moreover, HPLC is not a destructive technique, and therefore, proteins, once separated, are available for further analytical investigations. Among these techniques, quantitative and qualitative analyses of the separated fractions can be obtained through other biophysical approaches, such as crystallography or structural spectroscopy. Most of these approaches require preliminary protein purification (90% or higher), which could be rapidly obtained through preliminary HPLC.
Flow Injection Analysis Techniques in Atomic Spectroscopy
Authors: Cruz‐Alonso María , Sanz‐Medel Alfredo , Pereiro Rosario
Published: September 2016

Flow injection analysis (FIA), developed for the automation of serial assays, has become a powerful tool most adequate for on‐line performing any sample preparation before final measurement (e.g. sample dissolution, dilutions, matrix removal, and analyte preconcentration). It is not surprising that the combination of FIA with atomic spectrometric techniques has enlarged the analytical potential of atomic methods and expanded their field of applications, allowing also for greener procedures. The variety of sample manipulation processes that can be covered today by FIA is amazing, and therefore, the general instrumentation required is reviewed in this contribution.

The description of the different flow strategies is carried out according to a hierarchy going from simple dilutions, reagent mixing, or standard additions, to more sophisticated flow manifolds such as those based on the use of two phases (e.g. gas–liquid, liquid–liquid, or solid–liquid) for separation/preconcentration purposes. Modern approaches allowing for on‐line decomposition/dissolution of solid samples (e.g. photo‐oxidation and microwave heating) are also described.

The coupling of the above‐mentioned flow methodologies to a variety of atomization/excitation/ionization sources (flames, quartz tubes, graphite furnaces, inductively coupled plasmas, microwave induced plasmas, glow discharges, etc.) is detailed, aiming to show the usefulness of this combination for atomic techniques based on either photon measurements (absorption, emission, and fluorescence) or ion measurements (mass spectrometry, MS).