bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of light emission and sub‐bandgap defects in the dielectric response of electroluminescent diodes
Authors: Bansal Kanika 
Published: January 2013

AbstractConnection between junction impedance and modulated electroluminescence characteristics of light emitting devices of III‐V compounds is probed at low frequencies (≤100 kHz). Negative capacitance effect is observed accompanied by the onset of qualitatively similar modulated light emission as a systematic function of modulation frequency. Interdependent optical and electrical response at such low frequencies is explained by the role of defects in charge recombination dynamics which can cause reduction of radiative recombination efficiency for high frequency applications. Time domain behaviour of the negative capacitance has also been studied. Occurrence of negative capacitance can be identified by the monotonically decreasing shape of the current transient derivative. The characterization techniques used here can be helpful in optimizing the design of devices based on nitrides of III‐V compounds. However a more rigorous theoretical frame work is required for further analysis which may not follow the conventional semiconductor diode models based on depletion approximation and electrostatic description. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of hydrogen irradiation on the optical and electronic properties of site‐controlled InGaAsN V‐groove quantum wires
Authors: Felici Marco , Polimeni Antonio , Lavenuta Giovanna , Tartaglini Elena , De Luca Marta , Capizzi Mario , Notargiacomo Andrea , Carron Romain , Fekete Dan , Gallo Pascal , Dwir Benjamin , Rudra Alok , Kapon Eli , Pettinari Giorgio , Christianen Peter C. M. , Maan Jan C. 
Published: January 2013

AbstractThe properties of InGaAsN V‐groove QWRs are assessed here by polarization‐dependent photoluminescence (PL) and micro‐magneto‐PL. Both the polarization anisotropy of the QWR emission and the strong dependence of the diamagnetic shift on the orientation of the applied magnetic field confirm the 1D nature of the QWR excitons. Further, the possibility of passivating N impurities by H irradiation is used to estimate the N content (x) in the QWRs by turning off the effects of N incorporation. Both the H‐induced blueshift of the QWR emission (70 meV) and the measured value of the electron effective mass are consistent with x ∼1%. Nitrogen is also found to enhance the In intake in the QWR, likely due to the strain reduction resulting from the smaller lattice parameter of the InGaAsN alloy. Such strain reduction is also responsible for the quick decay of the degree of linear polarization (ρ) of the QWR emission with increasing temperature, indicating a small splitting between the QWR valence‐band levels. In fully hydrogenated samples, conversely, ρ remains roughly constant up to ∼240 K, suggesting the recovery of a larger energy separation between the QWR hole states upon N passivation. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recombination lifetime in InGaN/GaN based light emitting diodes at low current densities by differential carrier lifetime analysis
Authors: Riuttanen Lauri , Kivisaari Pyry , Mäntyoja Nikolai , Oksanen Jani , Ali Muhammad , Suihkonen Sami , Sopanen Markku 
Published: January 2013

AbstractCarrier lifetimes of the recombination processes in light emitting diodes (LEDs) depend strongly on the operating point. We measure the carrier lifetimes of InGaN/GaN LEDs at low current densities by applying the differential carrier lifetime analysis. In the measurement setup the LED is driven with constant current modulated with small amplitude alternating current (AC) and the carrier lifetime is obtained from the phase difference between input AC and light output.In addition to the optical method, we also extract the lifetimes directly from the capacitance and differential resistance of the LED obtained using an impedance analyzer and compare the results to lifetimes obtained by the optical setup. The carrier lifetimes were found to increase from hundreds of nanoseconds to microseconds when the current density was decreased from tens of A/cm2 to tens of mA/cm2. Both measurement methods resulted in similar lifetimes (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sensitivity of tropical‐cyclone models to the surface drag coefficient in different boundary‐layer schemes
Authors: Smith Roger K. , Montgomery Michael T. , Thomsen Gerald L. 
Published: January 2013

AbstractThe recent study of the sensitivity of tropical‐cyclone intensification to the surface drag coefficient in a three‐dimensional model by Montgomery et al. is extended to include a wind‐speed‐dependent drag coefficient and one of four boundary‐layer parametrization schemes: the bulk, Blackadar, MRF and Gayno–Seaman schemes. The schemes are slightly modified to have the same drag coefficient formulation and the same constant exchange coefficients for sensible heat and moisture. Interest is focussed on the change in intensity of the azimuthally‐averaged tangential wind speed and change in the low‐level vortex structure when the standard value of the drag coefficient is halved or doubled. Changing the drag coefficient provides insight into unbalanced effects in the boundary layer and their impact on the vortex evolution and structure. The changes in vortex behaviour with changing drag coefficient are qualitatively similar for all schemes, the maximum intensification occurring for a value somewhere near the standard value of the drag coefficient. The interpretation given to explain this behaviour underlines the intrinsically unbalanced nature of the boundary‐layer dynamics, although, for reasons discussed, a complete theory for the behaviour does not exist. The behaviour found is at odds with the predictions of Emanuel's (balance) theory for the maximum intensity of a tropical‐cyclone, which predicts a monotonic decrease in intensity with the drag coefficient if the enthalpy exchange coefficient is held fixed. It is at odds also with a recent numerical study of the maximum intensity by Bryan and Rotunno.The study underscores the importance of boundary‐layer dynamics in models for forecasting tropical‐cyclone intensity and the need for care in choosing a boundary‐layer scheme. However, it is not yet known which boundary‐layer formulation is the most appropriate for this purpose, highlighting the need for a concerted research effort in this direction.
Clonal Isolation of an Intermediate Pluripotent Stem Cell State
Authors: Chang Kuo-Hsuan , Li Meng 
Published: January 2013

Abstract
Pluripotent stem cells of different embryonic origin respond to distinct signaling pathways. Embryonic stem cells (ESCs), which are derived from the inner cell mass of preimplantation embryos, are dependent on LIF-Stat3 signaling, while epiblast stem cells (EpiSCs), which are established from postimplantation embryos, require activin-Smad2/3 signaling. Recent studies have revealed heterogeneity of ESCs and the presence of intermediate pluripotent stem cell populations, whose responsiveness to growth factors, gene expression patterns, and associated chromatic signatures are compatible to a state in between ESCs and EpiSCs. However, it remains unknown whether such cell populations represent a stable entity at single-cell level. Here, we describe the identification of clonal stem cells from mouse ESCs with global gene expression profiles representing such a state. These pluripotent stem cells display dual responsiveness to LIF-Stat3 and activin-Smad2/3 at single-cell level and thus named as intermediate epiblast stem cells (IESCs). Furthermore, these cells show accelerated temporal gene expression kinetics during embryoid body differentiation in vitro consistent with a more advanced differentiation stage than that of ESCs. The successful isolation of IESCs supports the notion that traverse from naïve ground state toward lineage commitment occurs gradually in which transition milestones can be captured as clonogenic entity. Our finding provides a new model to better understand the multiple pluripotent states.
The Four and a Half LIM-Domain 2 Controls Early Cardiac Cell Commitment and Expansion Via Regulating β-Catenin-Dependent Transcription
Authors: Renger Anke , Zafiriou Maria-Patapia , Noack Claudia , Pavlova Elena , Becker Alexander , Sharkova Krasimira , Bergmann Martin W. , El-Armouche Ali , Zimmermann Wolfram-Hubertus , Zelarayán Laura C. 
Published: January 2013

Abstract
The multiphasic regulation of the Wnt/β-catenin canonical pathway is essential for cardiogenesis in vivo and in vitro. To achieve tight regulation of the Wnt/β-catenin signaling, tissue- and cell-specific coactivators and repressors need to be recruited. The identification of such factors may help to elucidate mechanisms leading to enhanced cardiac differentiation efficiency in vitro as well as promote regeneration in vivo. Using a yeast-two-hybrid screen, we identified four-and-a-half-LIM-domain 2 (FHL2) as a cardiac-specific β-catenin interaction partner and activator of Wnt/β-catenin-dependent transcription. We analyzed the role of this interaction for early cardiogenesis in an in vitro model by making use of embryoid body cultures from mouse embryonic stem cells (ESCs). In this model, stable FHL2 gain-of-function promoted mesodermal cell formation and cell proliferation while arresting cardiac differentiation in an early cardiogenic mesodermal progenitor state. Mechanistically, FHL2 overexpression enhanced nuclear accumulation of β-catenin and activated Wnt/β-catenin-dependent transcription leading to sustained upregulation of the early cardiogenic gene Igfbp5. In an alternative P19 cell model, transient FHL2 overexpression led to early activation of Wnt/β-catenin-dependent transcription, but not sustained high-level of Igfbp5 expression. This resulted in enhanced cardiogenesis. We propose that early Wnt/β-catenin-dependent transcriptional activation mediated by FHL2 is important for the transition to and expansion of early cardiogenic mesodermal cells. Collectively, our findings offer mechanistic insight into the early cardiogenic code and may be further exploited to enhance cardiac progenitor cell activity in vitro and in vivo.
Inferring teacher epistemological framing from local patterns in teacher noticing
Authors: Russ Rosemary S. , Luna Melissa J. 
Published: January 2013

AbstractIn this work we use research from science education on teacher framing and work from mathematics education on teacher noticing to develop new approaches to modeling teacher cognition. The framing literature proposes a dynamic cognitive model of teaching in which teacher epistemological framing, or moment‐to‐moment understanding of what is going on with respect to knowledge and learning in the classroom, drives much of teacher practice. The teacher noticing literature documents patterns and trends in teachers' attention during instruction. We suggest first that noticing patterns, particularly local noticing patterns, can be leveraged to make inferences about teacher framing that maintain sensitivity to its dynamics but are also more reliable than existing analytic approaches. Second, we suggest that understanding noticing as driven by framing requires researchers to anticipate, allow for, and capitalize on the fact that teachers are capable of multiple, internally consistent variations in noticing at any given time. To illustrate these claims we present an analysis of one high school biology teacher who implemented a new digital recording technology in her classroom. Using the data from that implementation we identify two distinct local patterns in the teacher's noticing and from those patterns infer two different epistemological frames, one that she adopts during lab work and another during class discussions. We also discuss implications of these multiple framings for the study and training of teacher noticing more broadly. © 2013 Wiley Periodicals, Inc. J Res Sci Teach 50:284–314, 2013
What Would You Say? Genetic Counseling Graduate Students’ and Counselors’ Hypothetical Responses to Patient Requested Self‐Disclosure
Authors: Redlinger‐Grosse Krista , Veach Patricia McCarthy , MacFarlane Ian M. 
Published: January 2013

AbstractGenetic counselor self‐disclosure is a complex behavior that lacks extensive characterization. In particular, data are limited about genetic counselors’ responses when patients ask them to self‐disclose. Accordingly, this study investigated genetic counseling students’ (n = 114) and practicing genetic counselors’ (n = 123) responses to two hypothetical scenarios in which a female prenatal patient requests self‐disclosure. Scenarios were identical except for a final patient question: “Have you ever had an amniocentesis?” or “What would you do if you were me?” Imagining themselves as the counselor, participants wrote a response for each scenario and then explained their response. Differences in disclosure frequency for students vs. counselors and disclosure question were assessed, and themes in participant responses and explanations were extracted via content and thematic analysis methods. Chi‐square analyses indicated no significant differences in frequency of student versus counselor disclosure. Self‐disclosure was significantly higher for, “Have you ever had an amniocentesis?” (78.5 %) than for, “What would you do if you were me?” (53.2 %) (p < .001). Types of self‐disclosures includedpersonal,professional, andmixed disclosures. Prevalent explanations for disclosure and non‐disclosure responses included: remain patient focused and support/empower the patient. Additional findings, practice and training implications, and research recommendations are presented.
Patterns of abundance and co‐occurrence in aquatic plant communities
Authors: Chmara Rafał , Szmeja Józef , Ulrich Werner 
Published: January 2013

AbstractAquatic plants are well suited as subjects for studies on the distribution and abundance of co‐occurring species, especially due to the simple structure of their communities, well defined toposequences and relatively easily measurable environmental factors. Here we show that underwater plants occurring in semi‐natural lakes form stable communities, where species interactions dominate over dispersal dynamics to form a modular community structure with a high degree of zonation (turnover) and low within‐module species richness. In turn, human‐induced disturbance largely destroyed the modular structure. Our results indicate that (1) species abundance distributions (SADs) of underwater plant communities are well described by the lognormal model; (2) environmental characters did not significantly influence the SADs of underwater plant communities; (3) log‐series SADs do not indicate specific types of community organization; (4) in our lake communities only few satellites (tourists) occur; (5) the co‐occurrence of species is highly dependent on the turnover across lakes and water depth zones; and (6) species zonation is a function of lake properties.
Robert Bruce Foote: His Contribution to the Geology of Karnataka, the Southern Peninsular India and Indian Prehistory
Authors: Srikantia S.V. 
Published: January 2013

“Robert Bruce Foote is to be given the honoured place as the father of south Indian Geology”. “All students of Karnataka geology must salute this great veteran geologist who laid a firm foundation for the development of geological studies in the State. Thanks to the pioneering work of Bruce Foote, Karnataka retains even to this day a prominent position as holding a key to the understanding of early crustal processes and is attracting , not only geologists from other parts of India, but many reputed students of Earth Science from other parts of the world.”. These are the words of B.P.Radhakrishna (1994) written in Geology of Karnataka.
“Besides his purely geological work he was one of the earliest discoverers, and later a most enthusiastic investigator of relics of ancient man in Southern India; he formed an extensive collection of stone-implements, which is now deposited in the Madras Museum, and was for long recognised as a leading authority on this branch of research” wrote R.D. Oldham (1913) in his obituary reference extolling Foote’s passion for Prehistory.
The Vorticity Axis Flip and Its Control on Mineralization
Authors: Mamtani Manish A. 
Published: January 2013

Abstract
This paper discusses the possible role of vorticity axis flip in controlling fluid flow and consequent development of hydrothermal deposits. Structural, kinematic and vorticity data from the vicinity of the Singhbhum Shear Zone (SSZ) are used to propose a two stage model to explain hydrothermal mineralization. It is suggested that in the initial stage, fractures, weak planes, foliations and/or shear zones develop. Fracture permeability is weak at this stage, as a consequence of which fluid pressure builds up. Variation in stress orientation during a later stage of deformation results in enhancement of fracture network, fracture permeability and its anisotropy. If a significant vorticity axis flip accompanies this variation in stress orientation, then it pumps the fluids into the fracture network, thus yielding hydrothermal mineral deposits. In the case of SSZ, the vorticity axis flip is envisaged to have taken place from steeply plunging (anticlockwise) during the early stage, to sub-horizontal during the late stage. The SSZ became a northerly dipping thrust at this late stage and the rotation around the sub-horizontal vorticity axis was such that the rocks comprising the northern block were thrust over southern block (Singhbhum granitoid). According to the author, this vorticity axis flip must have been critical in pumping up the fluids along the SSZ to form quartz veins that host mineral deposits.
Morphometric Evidence of Seismicity around Wagad and Gedi Faults, Eastern Kachchh, Gujarat
Authors: Bhattacharya Falguni , Rastogi B. K. , Kothyari Girish C. 
Published: January 2013

Abstract
Recent studies suggest that the eastern Kachchh is a potential zone for major earthquakes in the near future. Particularly, the E-W trending faults are considered capable of generating large magnitude earthquakes is further indicated by the recent concentration of the earthquake shocks, which, show two prominent clustering around west and north of the Wagad upland. In view of this, the conventional morphometric analyses of a terrain bounded by the E-W trending North Wagad Fault (NWF) and the Gedi Fault (GF) has been undertaken to ascertain the influence of seismicity in the evolution of the drainage basin. The study suggests that the fifth order drainage basins responded to the seismicity associated with both the NWF and GF. However, compared to the GF, the NWF seems to be more active. In addition to this, based on the stream morphology, we could identify two lineaments trending N-S and E-W. The former appears to be associated with the activity along the Manfara Fault (MF), whereas, the later seems to be the splays of the NWF. Further, a preferential westward shift of the streams suggests left lateral displacement of the E-W trending faults. Overall it can be suggested that the terrain is in juvenile stage implying tectonic instability.
Heavy Mineral Distribution and Characterisation of Ilmenite of Kayamkulam - Thothapally Barrier Island, Southwest Coast of India
Authors: Nallusamy Babu , Babu Sinirani , Babu D. S. Suresh 
Published: January 2013

Abstract
Mineral concentration and ilmenite characterization of the Thothapally - Kayamkulam Barrier Island of the southern Kerala has been studied. 96.86% concentrations of heavy minerals are recorded in the surficial and core samples (4 m) in the southern Kayamkulam and northern Thothapally areas. The total heavy mineral content decreases with depth. The primary heavy mineral suite of the surficial and core samples consists of ilmenite, sillimanite, zircon, garnets, rutile, monazite and magnetite. Longshore current and onshore- offshore movements of sediment during the southwest monsoon are primarily responsible in sorting of the heavy minerals. TiO2 content in ilmenite is significantly higher in the Kayamkulam core sediments than the surface samples. XRD analysis supports intensive weathering and alteration leading to the higher TiO2 concentration. Higher percentage of ferric iron than ferrous iron in the core samples reveals that considerable weathering occurred under burial condition. SEM examination of ilmenite grains reveal the presence of solution pit, chemical leaching, corrosion and replacement textures, supporting the intense epigenetic alteration and weathering under subaerial condition and post- depositional changes by water–table condition.
THE DYNAMICS OF LAND TENURE SYSTEMS IN THE NIGER BASIN, MALI
Authors: Camara Bakary 
Published: January 2013

ABSTRACTThis article examines, through different processes of changing land use and land tenure, the various types of formal and informal contractual relations existing in two areas of the Niger Basin in southern Mali that are dominated economically by two parastatal companies: Compagnie Malienne pour le Développement du Textile (CMDT) and Office du Niger (ON). The article shows how the production interventions of these two companies shape the framework of land administration in the Niger Basin and the context in which customary relations operate, and lead to the commodification of land relations. It traces the various routes, contracts and arrangements through which people gain access to agricultural land. Besides describing the various transactions in land and contractual relationships, the article also analyses land leasing, sharecropping and various other ways of gaining secondary rights through prestations and loans. Finally, it describes the various land conflicts, the actors involved in making various claims on land and claims to land administration, and the institutions and institutional pluralism that emerge in conflict resolution. The article links these to the increasing commodification of land and agriculture, and the domination of policy by economic liberalism.
THE CRISIS OF PUBLIC POLICIES IN CÔTE D'IVOIRE: LAND LAW AND THE NATIONALITY TRAP IN TABOU'S RURAL COMMUNITIES
Authors: Babo Alfred 
Published: January 2013

ABSTRACTThis article explores the ways in which the Ivoirian Land Code of 1998 has played into political debates around national citizenship that have divided Ivoirian society since the 1990s. The attempts to reinterpret public policies on land and immigration have played a crucial role in exacerbating the political crisis of nationalism. When land was linked to nationality and indigeneity, the land question became significant in determining the boundaries of nationality, since to gain security in property rights Ivoirian nationality had to be proved. The article traces how land policy has been transformed from an inclusive framework that encouraged the rapid expansion of the cocoa and coffee frontiers in the 1970s to an exclusionary policy rooted in concepts of nationalism and autochthony, as land became increasingly scarce in the south-west. The Land Code of 1998 endorsed this nationalism, preventing foreigners and their descendants from owning land. Through an example of a conflict in Tabou in which Burkinabé migrants were ejected from the land, the article shows how customary land values have been recreated to take on nationalistic, xenophobic values, according to which ethnic identities become conflated with distinctions between ‘indigenous’ and ‘foreign’, and land relations are defined as between ethnic groups rather than being contractual relations between individuals belonging to different groups: thus social identities become more exclusive.