bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential role of NF‐κB in adult neural stem cells: the underrated steersman?
Authors: Widera Darius , Mikenberg Ilja , Kaltschmidt Barbara , Kaltschmidt Christian
Published: January 2006

Neural stem cells are precursors of neurons and glial cells. During brain development, these cells proliferate, migrate and differentiate into specific lineages. Recently neural stem cells within the adult central nervous system were identified. Informations are now emerging about regulation of stem cell proliferation, migration and differentiation by numerous soluble factors such as chemokines and cytokines. However, the signal transduction mechanisms downstream of these factors are less clear.

Here, we review potential evidences for a novel central role of the transcription factor nuclear factor kappa B (NF‐κB) in these crucial signal transduction processes.

NF‐κB is an inducible transcription factor detected in neurons, glia and neural stem cells. NF‐κB was discovered by David Baltimore's laboratory as a transcription factor in lymphocytes [Nabel, G., Baltimore, D., 1987. An inducible transcription factor activates expression of human immunodeficiency virus in T cells. Nature 326 (6114), 711–713]. NF‐κB is involved in many biological processes such as inflammation and innate immunity, development, apoptosis and anti‐apoptosis. It has been recently shown that members of the NF‐κB family are widely expressed by neurons, glia and neural stem cells [Kaltschmidt, B., Kaltschmidt, C., 2003. NF‐κB in the nervous system. In: R. Beyaert (Ed.), Nuclear Factor κB. Regulation and Role in Disease. Kluwer Academic Publishers, pp. 375–394; Denis‐Donini, S., Caprini, A., et al., 2005. Members of the NF‐κB family expressed in zones of active neurogenesis in the postnatal and adult mouse brain. Brain Res. Dev. Brain Res. 154 (1), 81–89]. In the nervous system, NF‐κB plays a crucial role in neuronal plasticity, learning, memory consolidation, neuroprotection and neurodegeneration, for review, see [Kaltschmidt, B., Widera, D., et al., 2005. Signaling via NF‐kappaB in the nervous system. Biochim. Biophys. Acta]. Recent data suggest an important role of NF‐κB on proliferation, migration and differentiation of neural stem cells.

NF‐κB is composed of three subunits: two DNA‐binding and one inhibitory subunit. Activation of NF‐κB takes place in the cytoplasm and results in degradation of the inhibitory subunit, thus enabling the nuclear import of the DNA‐binding subunits. Within the nucleus, several target genes could be activated.

In this review, we suggest a model explaining the multiple action of NF‐κB on neural stem cells. Furthermore, we discuss the potential role of NF‐κB within the so‐called brain cancer stem cells.
Creating supply chain relational capital: The impact of formal and informal socialization processes
Authors: Cousins Paul D. , Handfield Robert B. , Lawson Benn , Petersen Kenneth J.
Published: January 2006

Establishing closer social ties between buying and supplying organizations is increasingly cited as a critical differentiator of high and low performers in global supply chains. While the creation of relational capital within an organization is a relatively well identified concept in organizational research, comparatively little research exists on the inter‐organizational socialization processes that create relational value in supply chains. In our research, we extend theoretical models of group social conduits into this context, and develop a model that posits the impact of formal and informal socialization processes on the creation of relational capital between buyers and suppliers. Results from our study of 111 manufacturing organizations in the United Kingdom suggest that informal socialization processes are important in the creation of relational capital, which in turn can lead to improved supplier relationship outcomes. Formal bridging socialization conduits appear to play a lesser role in deriving these benefits.
Behavior in operations management: Assessing recent findings and revisiting old assumptions
Authors: Bendoly Elliot , Donohue Karen , Schultz Kenneth L.
Published: January 2006

In this paper, we provide a perspective on why behavioral research is critical to the operations management (OM) field, what prior research exists, and what opportunities lie ahead. The use of human experiments in operations management is still fairly novel despite a small stream of publications going back more than 20 years. We develop a framework for identifying the types of behavioral assumptions typically made in analytical OM models. We then use this framework to organize the results of prior behavioral research and identify future research opportunities. Our study of prior research is based on a search of papers published between 1985 and 2005 in six targeted journals including the Journal of Operations Management, Manufacturing and Service Operations Management, Production and Operations Management, Management Science, Decision Sciences, and the Journal of Applied Psychology.
Mammals of the high altitudes of western Arunachal Pradesh, eastern Himalaya: an assessment of threats and conservation needs
Authors: Mishra Charudutt , Madhusudan M.D. , Datta Aparajita
Published: January 2006

The high altitudes of Arunachal Pradesh, India, located in the Eastern Himalaya biodiversity hotspot, remain zoologically unexplored and unprotected. We report results of recent mammal surveys in the high altitude habitats of western Arunachal Pradesh. A total of 35 mammal species (including 12 carnivores, 10 ungulates and 5 primates) were recorded, of which 13 are categorized as Endangered or Vulnerable on the IUCN Red List. One species of primate, the Arunachal macaque Macaca munzala, is new to science and the Chinese goral Nemorhaedus caudatus is a new addition to the ungulate fauna of the Indian subcontinent. We documented peoples' dependence on natural resources for grazing and extraction of timber and medicinal plants. The region's mammals are threatened by widespread hunting. The snow leopard Uncia uncia and dhole Cuon alpinus are also persecuted in retaliation for livestock depredation. The tiger Panthera tigris, earlier reported from the lower valleys, is now apparently extinct there, and range reductions over the last two decades are reported for bharal Pseudois nayaur and musk deer Moschus sp.. Based on mammal species richness, extent of high altitude habitat, and levels of anthropogenic disturbance, we identified a potential site for the creation of Arunachal's first high altitude wildlife reserve (815 km2). Community-based efforts that provide incentives for conservation-friendly practices could work in this area, and conservation awareness programmes are required, not just amongst the local communities and schools but for politicians, bureaucrats and the army.
A reassessment of the distribution and taxonomy of the Endangered otter civet Cynogale bennettii (Carnivora: Viverridae) of South-east Asia
Authors: Veron Géraldine , Gaubert Philippe , Franklin Neil , Jennings Andrew P. , Grassman Jr Lon I.
Published: January 2006

The otter civet Cynogale bennettii is a specialized, semi-aquatic viverrid found throughout the forests of South-east Asia. Although described over 160 years ago, little is known of the species' natural history, and questions remain regarding its taxonomy and distribution. We compiled an exhaustive list of museum specimens and observations to reassess the conservation status, taxonomy and distribution of this species. Data were collected from museums, literature, field surveys, and from other field scientists. Although two species of otter civet have been described, C. bennettii and C. lowei, our morphological examinations do not support specific differentiation. The presence of the otter civet was confirmed for peninsular Thailand, Malaysia and the islands of Sumatra and Borneo. However, more northerly distributions were not confirmed, including the supposed origin of C. lowei from northern Vietnam. Based on the scarcity of recent observations or carcasses, otter civet populations are probably in decline. Recent increases in the number of wildlife surveys throughout the putative range of the otter civet have rarely documented the species. The reduction in primary forest habitat has probably reduced otter civet populations and threatens the persistence of this unique species.
Conservation status of the littoral forest of south-eastern Madagascar: a review
Authors: Bollen An , Donati Giuseppe
Published: January 2006

The littoral forest of the Fort Dauphin region of south-east Madagascar is expected to lose numerous endemic plant and animal species in the near future as a result of deforestation and consequent habitat changes. The disruption of plant-animal interactions is of particular concern. This review describes the conservation status of the littoral forest of Sainte Luce, Fort Dauphin, and examines the role of animal-facilitated seed dispersal in regeneration. The main threats to this habitat are described and possible management implications are discussed in relation to existing initiatives. Protection of the largest remaining forest fragments has been agreed by local communities and a draft plan for forest management is currently under evaluation. Over the next few years plantations will be created to provide local people with wood for fuel and other purposes. An important flying fox Pteropus rufus roost site needs to be included in conservation plans because of its importance for long-distance seed dispersal. Despite the presence of natural barriers, the creation of forest corridors will be crucial for connecting isolated fragments and facilitating genetic exchange between subpopulations. Increased attention needs to be given to the need to promote conservation-related income activities.
Aphids and scale insects on threatened trees: co-extinction is a minor threat
Authors: Thacker Jonathan I. , Hopkins Graham W. , Dixon Anthony F.G.
Published: January 2006

Co-extinction is the extinction of a species following the extinction of another species that it used as a resource, such as a food plant in the case of insect herbivores. The magnitude of the global co-extinction threat to two herbivorous insect taxa (aphids and scale insects) was estimated by compiling a list of species in these groups that are dependent on globally threatened trees. Eleven species of aphid (0.69%) and thirteen scale insects (1.15%) have a threatened tree as their sole host. This measure is comparable to recent estimates for insect herbivores, but far less than the published overall estimates of extinction risk for invertebrates, and highlights the dependence of insect herbivores on a wide range of habitat features.
A transcontinental distribution
Authors: McArthur Tom
Published: January 2006

The difference over twenty years, in the making of ET since 1985,
includes the vanishing away of paper files. In a cabinet beside my desk
I have A–Z files for the many people who literally ‘wrote’ – that is,
typed – to me on paper. I almost never consult any of those files now,
and don’t remember when I last added a sheet to them. Instead, of
course, I check my email, which piles up electronically in non-real
space somewhere inside this machine in front of me. And, though I
strive to keep my records straight, I seldom check back very far or go
into e-files of old e-mails. And, most days, whether in Cambridge or in
Hong Kong, I read daily e-abstracts from my much-prized Edinburgh
newspaper, The Scotsman, and don't recall when I last saw, leave alone
bought and read, a conventional paper edition of it.
Some reflections on English as a ‘semi-sacred’ language
Authors: Asker Barry
Published: January 2006

BY GENERAL consensus English has become, if not a global language, then at the very least a lingua franca. Some commentators on English in the world, like Robert Phillipson (Linguistic Imperialism (Oxford University Press, 1992), use the term that serves him as a title to imply that English is itself part of the problem of having just such a global language. The argument here however is that English – like Latin, Sanskrit, Classical Arabic and Examination Chinese – through its political ascendancy (as a result of various waves of colonial activity alongside its use for religious purposes), may have taken on the character of a ‘semi-sacred’ rather than simply an imperial and imperialist language.
Cut-down puns
Authors: Lillo Antonio
Published: January 2006

SLANG IS characterized by its capacity to shock, startle and amuse: often achieved by manipulating existing lexical material in a playful way. Indeed, this play instinct is at the core of language use at large: cf. Nilsen & Nilsen (1978:28–44), Redfern (1984:6), and especially Crystal (1998). It is however in the realm of informal discourse that all types of ludic word-forming – from malapropisms to homonymic puns – thrive most richly. One such way of manipulating existing lexical items is to expand them implicitly into longer forms so that the original does double (and often facetious) duty. This process is at work not only in such acronyms as S.F.A. – impeccably, Scottish Football Association, but facetiously both sweet fuck-all and its euphemistic variant Sweet Fanny Adams – but also in such elaborations as do-re-mi for ‘dough’ (US slang money), Oswald for ‘an ounce’ of a drug (expanding oz, the abbreviation of ‘ounce’), and Georgie (after the late renowned footballer George or Georgie Best), for ‘best’ itself. The following article seeks to explore the curious realm of curtailed puns formed on the same principle as Georgie.
Linguistic notes on English orthography and current usage
Authors: Kaye Alan S.
Published: January 2006

Two inter-related essays deal with matters of current English usage. The first is on an orthographic theme, while the second is on a lexical one. (1) On the letters ‘ph’ in English, (2) On Beedham on Pinker on ‘computer mouse’
Schema theory and the humour of Little Britain
Authors: Snell Julia
Published: January 2006

LITTLE BRITAIN is a television comedy show in the UK. Recurring characters appear in its episodes enacting situations that can be said to satirize British society. It was first aired by the BBC in February 2003. Little Britain has quickly amassed a loyal following and has grown significantly in popularity. It has won a number of prestigious comedy awards including ‘Best Comedy Performance’ and ‘Comedy Programme or Series Award’ at the BAFTAs (British Academy of Film and Television Arts awards, 2005). The humour in Little Britain has therefore been successful. Moreover, it is not based purely on visual comedy, being originally launched on BBC Radio 4 then transferred to television. Its humour originates in the language used. Schema theory, a useful tool for analysing much situational comedy, can shed light on the construction and interpretation of humour in Little Britain
“Déjà Vu” or Memory-Science between Gérard de Nerval and Marcel Proust
Authors: Ender Evelyne
Published: January 2006

Argument

Cultivated by a number of writers and studied by psychologists, the phenomenon of déjà vu is an invention of the nineteenth century and is part of a broader exploration of how the mind experiences memory and time. Thus this typically benign mental aberration provides an entry-point into the mechanisms that preside over the regulation of the flow of consciousness. The theories of the mind developed recently by neuroscientists help us understand, meanwhile, why investigations into this mental “event” necessarily invoke concepts of representation and narrative. In fact, our increasingly sophisticated models for processes of memory and perception depend on literary representations. This article relies on the paramnesiac writings of Gérard de Nerval, seen through the lens of Proust's analysis, to argue that a consideration of the aesthetic and representational features of déjà-vu can bring us closer to solving the epistemological challenges we face in studying this phenomenon.

For Gregory T. Polletta
Comparative Epistemology of Suspicion: Psychoanalysis, Literature, and the Human Sciences
Authors: Strowick Elisabeth
Published: January 2006

Argument

In calling psychoanalysis a “school of suspicion” (Ricoeur 1970, 32), Ricoeur marks at once its use in a disposition characteristic of modernity: the disposition of suspicion. Modernity gives rise to various forms of suspicion, to modern forms of ressentiment and practices of disciplining oneself (the suspicion of oneself) as well as to an epistemology of suspicion. In this essay, I shall analyze the epistemological function of suspicion – which as the “paradigm of clues” (Ginzburg 1988) becomes the leading paradigm of the human sciences in the last third of the nineteenth century – and its close interrelationship with the techniques of power. As I shall demonstrate through a comparative reading of psychoanalytical, literary, and criminological texts, the modern production of knowledge in the human sciences cannot be separated from the modern “micro-physics of power,” which for Foucault was established in the eighteenth century, and the technologies of the self. I shall situate the paradigm of clues within the framework of the modern disposition of suspicion in order to combine the epistemological reflections with an analysis of cultural history. Thus I will first examine the paradigm of clues from the perspectives of cultural theory (Foucault and Nietzsche) and semiotics (Peirce), in order to illuminate the structural unreliability of the episteme as well as the way it is closely linked to the techniques of power. In what follows, I will apply this view to Bertillon's photographic identification system, the psychoanalytical concept of the trace, and Kafka's short story The Burrow.
High supersaturation and modes of ice nucleation in thin tropopause cirrus: Simulation of the 13 July 2002 Cirrus Regional Study of Tropical Anvils and Cirrus Layers case
Authors: Khvorostyanov Vitaly I. , Morrison Hugh , Curry Judith A. , Baumgardner Darrel , Lawson Paul
Published: January 2006

A unique and extensive data set of cirrus properties collected on 13 July 2002 during CRYSTAL‐FACE provides the framework for simulations using cloud models to interpret the observations and to develop recommendations for microphysical parameterizations in large‐scale models. Several outstanding issues in the simulations of cirrus clouds are addressed using detailed bin‐resolving and bulk microphysics models. A new heterogeneous ice nucleation formulation based on extended classical theory with simultaneous dependence on temperature and saturation ratio is applied for the first time to thin tropopause cirrus. The simulated cloud microphysical properties are similar to observations, suggesting that tropopause cirrus may potentially form as a result of heterogeneous immersion freezing of internally mixed aerosols serving as ice nuclei (IN). The potential for mixed aerosols to serve as IN in tropopause cirrus is consistent with measurements of comparable amounts of soluble and insoluble material in cirrus residues and aerosols during CRYSTAL‐FACE. Simulations using homogeneous nucleation theory are also able to produce comparable microphysical properties if the heterogeneous mode is turned off; hence the homogeneous mode cannot be excluded if insoluble material capable of serving as IN is not available. The calculated critical ice supersaturation for the onset of heterogeneous nucleation at these cold temperatures (∼200 K) was 70–80% (for the assumed aerosol nucleation parameters) and 15–20% higher for homogeneous nucleation. The calculated supersaturation relaxation time ranged from ∼1–2 hours in the center of the cloud to 3–6 hours near the boundaries, which may explain the high values of ice supersaturation (30–80%) observed in this cloud. Analysis of the supersaturation budget showed that supersaturation was generally nonequilibrium, and relaxation from the initial critical values to near equilibrium occurred only after several hours. The bulk model was able to simulate this case and in particular the slow crystal growth and large supersaturation because of its detailed treatment of ice nucleation and supersaturation. The fraction of condensed ice relative to excess vapor predicted by both models was 40–60% for several hours, indicating that bulk models with zero supersaturation (instantaneous condensation of all excess vapor) would substantially overpredict the ice water path and optical thickness.
Secular increase of seasonal predictability for the 20th century
Authors: Kang In‐Sik , Jin Emilia Kyung , An Kyong‐Hee
Published: January 2006

Seasonal predictability of global surface air temperature for the 100 years of 20th century is examined using the Climate of the 20th Century international project (C20C) AGCM experiment. The C20C experiments reproduce reasonably well the observed warming trend over the globe. The perfect model concept, one simulation being considered as observation, is utilized to examine the changes of seasonal mean predictability for the last 100 years. The global pattern correlations of seasonal mean temperature show clearly the seasonal mean predictability being increased since 1920s. The analysis of the ensemble mean and deviation also shows that the signal to noise ratio is much increased for the recent 30 years, particularly in the tropical and subtropical Pacific. The increase of the seasonal predictability is found to be related to the enhancement of SST variability over the tropical Pacific, which appears to be related to the global warming.
Controls on methanol and acetone in marine and continental atmospheres
Authors: Mao Huiting , Talbot Robert , Nielsen Carsten , Sive Barkley
Published: January 2006

We present a regional analysis of CH3OH and (CH3)2CO in the New England continental and coastal marine atmospheres. Vegetative emissions over land comprise 60–80% of the daily peak‐to‐peak differences in the diurnal cycles of these oxygenated hydrocarbons. In the morning downward mixing of remnant boundary layer air over land provides an additional source equal to more than half of the vegetative emission strength. The ocean is both a sink and a source of CH3OH and (CH3)2CO, with dry depositional losses 2‐fold greater than their source counterparts of 0.35 and 0.17 ppbv d−1 respectively. Anthropogenic emissions compensate for 59% and 52% of CH3OH and (CH3)2CO oceanic sink respectively, whereas over land this source is relatively small compared to substantial vegetative sources. Direct measurements of ocean‐ and land‐air fluxes of CH3OH and (CH3)2CO and boundary layer height are needed to better constrain their regional budgets.
Interannual rainfall variability in the tropical Atlantic region
Authors: Gu Guojun , Adler Robert F.
Published: January 2006

Rainfall variability on seasonal and interannual‐to‐interdecadal timescales in the tropical Atlantic is quantified using a 25‐year (1979–2003) monthly rainfall data set from the Global Precipitation Climatology Project. The Intertropical Convergence Zone (ITCZ), measured by monthly rainfall between 15° and 37.5°W, attains its peak as it moves to the northernmost latitude (∼8°–10°N) during July–September, during which the most total rainfall is observed in the tropical Atlantic basin (17.5°S to 22.5°N, 15°–37.5°W); the ITCZ becomes weakest during January–February, with the least total rainfall observed as it moves to the south. In contrast, rainfall variability on interannual‐to‐interdecadal timescales shows a quite different seasonal preference. The most intense interannual variability occurs during March–May, when the ITCZ tends to be near the equator and becomes weaker. The relationships between rainfall anomalies in the tropical Atlantic and three distinct sea surface temperature (SST) modes are further explored on interannual‐to‐interdecadal timescales. The ITCZ strength and total rainfall amount in the tropical Atlantic basin are significantly modulated by the Pacific El Niño and the Atlantic equatorial mode (or Atlantic Niño) particularly during boreal spring and summer, whereas the impact of the Atlantic interhemispheric mode is considerably weaker. Regarding the anomalous latitudes of the ITCZ, the influence could come from both local, i.e., the Atlantic interhemispheric and equatorial modes, and remote forcings, i.e., El Niño; however, a direct impact of El Niño on the latitudes of the ITCZ can only be found during April–July, not in winter and early spring, during which the largest SST anomalies are usually observed in the equatorial Pacific.
Reconciliation of coarse mode sea‐salt aerosol particle size measurements and parameterizations at a subtropical ocean receptor site
Authors: Reid Jeffrey S. , Brooks Barbara , Crahan Katie K. , Hegg Dean A. , Eck Thomas F. , O'Neill Norm , de Leeuw Gerrit , Reid Elizabeth A. , Anderson Kenneth D.
Published: January 2006

In August/September of 2001, the R/P FLIP and CIRPAS Twin Otter research aircraft were deployed to the eastern coast of Oahu, Hawaii, as part of the Rough Evaporation Duct (RED) experiment. Goals included the study of the air/sea exchange, turbulence, and sea‐salt aerosol particle characteristics at the subtropical marine Pacific site. Here we examine coarse mode particle size distributions. Similar to what has been shown for airborne dust, optical particle counters such as the Forward Scattering Spectrometer Probe (FSSP), Classical Scattering Aerosol Spectrometer Probe (CSASP) and the Cloud Aerosol Spectrometer (CAS) within the Cloud Aerosol and Precipitation Spectrometer (CAPS) instrument systematically overestimate particle size, and consequently volume, for sea salt particles. Ground‐based aerodynamic particle sizers (APS) and AERONET inversions yield much more reasonable results. A wing pod mounted APS gave mixed results and may not be appropriate for marine boundary layer studies. Relating our findings to previous studies does much to explain the bulk of the differences in the literature and leads us to conclude that the largest uncertainty facing flux and airborne cloud/aerosol interaction studies is likely due to the instrumentation itself. To our knowledge, there does not exist an in situ aircraft system that adequately measures the ambient volume distribution of coarse mode sea salt particles. Most empirically based sea salt flux parameterizations can trace their heritage to a clearly biased measurement technique. The current “state of the art” in this field prevents any true form of clear sky radiative “closure” for clean marine environments.
A classical trajectory study of the photodissociation of T1 acetaldehyde: The transition from impulsive to statistical dynamics
Authors: Thompson Keiran C. , Crittenden Deborah L. , Kable Scott H. , Jordan Meredith J. T.
Published: January 2006

Previous experimental and theoretical studies of the radical dissociation channel of T1 acetaldehyde show conflicting behavior in the HCO and CH3 product distributions. To resolve these conflicts, a full-dimensional potential-energy surface for the dissociation of CH3CHO into HCO and CH3 fragments over the barrier on the T1 surface is developed based on RO-CCSD(T)/cc-pVTZ(DZ) ab initio calculations. 20 000 classical trajectories are calculated on this surface at each of five initial excess energies, spanning the excitation energies used in previous experimental studies, and translational, vibrational, and rotational distributions of the radical products are determined. For excess energies near the dissociation threshold, both the HCO and CH3 products are vibrationally cold; there is a small amount of HCO rotational excitation and little CH3 rotational excitation, and the reaction energy is partitioned dominantly (>90% at threshold) into relative translational motion. Close to threshold the HCO and CH3 rotational distributions are symmetrically shaped, resembling a Gaussian function, in agreement with observed experimental HCO rotational distributions. As the excess energy increases the calculated HCO and CH3 rotational distributions are observed to change from a Gaussian shape at threshold to one more resembling a Boltzmann distribution, a behavior also seen by various experimental groups. Thus the distribution of energy in these rotational degrees of freedom is observed to change from nonstatistical to apparently statistical, as excess energy increases. As the energy above threshold increases all the internal and external degrees of freedom are observed to gain population at a similar rate, broadly consistent with equipartitioning of the available energy at the transition state. These observations generally support the practice of separating the reaction dynamics into two reservoirs: an impulsive reservoir, fed by the exit channel dynamics, and a statistical reservoir, supported by the random distribution of excess energy above the barrier. The HCO rotation, however, is favored by approximately a factor of 3 over the statistical prediction. Thus, at sufficiently high excess energies, although the HCO rotational distribution may be considered statistical, the partitioning of energy into HCO rotation is not.
Nucleation of atomic-layer-deposited HfO2 films, and evolution of their microstructure, studied by grazing incidence small angle x-ray scattering using synchrotron radiation
Authors: Green M. L. , Allen A. J. , Li X. , Wang J. , Ilavsky J. , Delabie A. , Puurunen R. L. , Brijs B.
Published: January 2006

We report the results of grazing incidence small angle x-ray scattering experiments on the nucleation and growth of atomic layer deposited HfO2 films. The scattering features are internal (porosity) and external (roughness) surfaces. Films grown on H-terminated Si exhibit greater scattering than films grown on chemically oxidized Si. The films grown on H-terminated Si may be as much as 50% porous. Characteristic scattering feature sizes are those of the film nuclei, about 2 nm, which then coalesce and become inherited features of the films. Films grown on chemically oxidized Si are observed to coalesce at about 25 growth cycles.
Complex channel networks of bone structure
Authors: da Fontoura Costa Luciano , Viana Matheus Palhares , Beletti Marcelo Emílio
Published: January 2006

Bone structure in mammals involves a complex network of channels (Havers and Volkmann channels) required to nourish the bone cells. This work describes how three-dimensional reconstructions of such systems can be obtained and represented in terms of complex networks. Three important findings are reported: (i) The fact that the channel branching density resembles a power law implies the existence of distribution hubs; (ii) the joint node degree density indicates a clear tendency of connection involving nodes with degree 3; and (iii) the application of the recently introduced concept of hierarchical clustering coefficient allows the identification of typical scales of channel redistribution. A series of relevant biological insights is drawn and discussed.
Filling of single silicon nanocrystals within multiwalled carbon nanotubes
Authors: Švrček V. , Pham-Huu C. , Ledoux M.-J. , Le Normand F. , Ersen O. , Joulie S.
Published: January 2006

We demonstrate here a simple approach to introduce the ex situ synthesized silicon nanocrystals (Si-ncs) embedded in SiO2 based spin on glass (SOG) within multiwalled carbon nanotubes (MWNTs) at room temperature and atmospheric pressure. After opening the ends of MWNTs and declustering the Si-ncs dispersed in the SOG solution, it is possible to introduce them inside MWNTs channel through capillary effect. In this letter, we present the initial explorations of carrying the stabilized Si-ncs in SOG inside nanotubes far from their ends by capillary forces. The results here described have important implications to further expand the useability of Si-ncs/MWNTs and might find very important applications in optoelectronics.
Structural and electrical evolution of gate dielectric breakdown observed by conductive atomic force microscopy
Authors: Zhang Li , Mitani Yuichiro
Published: January 2006

To clarify the breakdown (BD) mechanism in the gate oxide of transistors, BD evolution from prebreakdown (pre-BD) stage to BD transient is investigated by conductive atomic force microscopy. High electric fields of both polarities are applied to induce pre-BD degradation. Structural hillocks are observed to be dependent on stress polarity. The height of hillocks increases with BD evolution while keeping a similar lateral size. Flatband shift caused by negative charge is observed independent of stress polarity. Lateral size of the electrical degradation is similar to that of the hillock throughout BD evolution. We attribute the hillocks to deformation of Si substrate at the pre-BD stage, where an electrothermal effect plays an important role.
Visible resonant modes in GaN-based photonic crystal membrane cavities
Authors: Meier Cedrik , Hennessy Kevin , Haberer Elaine D. , Sharma Rajat , Choi Yong-Seok , McGroddy Kelly , Keller Stacia , DenBaars Steven P. , Nakamura Shuji , Hu Evelyn L.
Published: January 2006

Photonic crystal membrane cavities play a key role as building blocks in the realization of several applications, including quantum information and photonic circuits. Thus far, there has been no work on defect cavities with active layers emitting in the UV to green range of the spectrum based on the (Al,In,Ga)N material system. While this material system has great potential for a new generation of optoelectronic devices, there are several obstacles for the fabrication of GaN-based membrane cavities, including the absence of a conventional selective chemical wet etch. Here, we demonstrate the first fabrication of fully undercut GaN photonic crystal membranes containing an InGaN multiquantum well layer, fabricated using band-gap-selective photoelectrochemical etching. A postfabrication coating of Ta2O5 is used to tune the cavity modes into resonance with the quantum well emission, and the fabricated membranes exhibit resonant modes with Q=300.
Optical emission spectroscopy study for optimization of carbon nanotubes growth by a triode plasma chemical vapor deposition
Authors: Lim Sung Hoon , Yoon Hyun Sik , Moon Jong Hyun , Park Kyu Chang , Jang Jin
Published: January 2006

We carried out the in situ analysis of chemical species for the growth of carbon nanotubes (CNTs), deposited by a triode plasma enhanced chemical vapor deposition with a C2H2 and NH3 mixture, using optical emission spectroscopy (OES). A positive mesh bias enhances the radical density, thus increasing the growth rate. The vertically aligned CNTs were grown at a 50% C2H2 flow rate ratio to NH3 and mesh bias voltage of +300V, resulting from the increased CH radical density and the decreased H and CN radical density through the OES analysis.
Composition and resistivity changes of reactively sputtered W–Si–N thin films under vacuum annealing
Authors: Vomiero A. , Boscolo Marchi E. , Mariotto G. , Quaranta A. , Della Mea G. , Ottaviani G. , Tonini R. , Butturi M. , Martinelli G.
Published: January 2006

W–Si–N layers about 200nm thick with different nitrogen content were reactively sputtered from a W5Si3 target on oxidized silicon substrates. The thermal stability of the films’ composition and resistivity was studied with ion beam analysis and four-point probe measurements. Upon vacuum annealing from 600to980°C for 1.5h, a sample with an initial 56at.% of nitrogen gradually loses nitrogen down to 36%. This composition lies close to the W–Si3N4 tie line. Concurrently, the room temperature resistivity decreases from 4.7 to about 2mΩcm. The composition changes only a little for a sample whose initial composition is near the W–Si3N4 tie line and the resistivity changes significantly less than for the nitrogen-rich film. Interpretations are discussed.
Response of perennial ryegrass (Lolium perenne) to renovation in Australian dairy pastures
Authors: Callow M. N. , Fulkerson W. J. , Donaghy D. J. , Morris R. J. , Sweeney G. , Upjohn B.
Published: January 2006

This study reports on the effect of oversowing perennial ryegrass (Lolium perenne L.) into a degraded perennial ryegrass and white clover (Trifolium repens L.) pasture to extend its productive life using various intensities of seedbed preparation. Sites in New South Wales (NSW), Western Australia (WA), South Australia (SA) and Tasmania (Tas.) were chosen by a local group of farmers as being degraded and in need of renovation. Control (nil renovation) and medium (mulch and graze, spray with glyphosphate and sow) renovation treatments were common to all sites whereas minimum (mulch and graze, and sow) and full seedbed (graze and spray with glyphosphate and then full seedbed preparation) renovation were imposed only at some sites. Plots varied in area from 0.14 to 0.50 ha, and were renovated then sown in March or April 2000 and subsequently grazed by dairy cows. Pasture utilisation was estimated from pre- and post-grazing pasture mass assessed by a rising plate pasture meter.
Utilised herbage mass of the renovated treatments was significantly higher than control plots in period 1 (planting to August) and 2 (first spring) at the NSW site only. There was no difference among treatments in period 3 (first summer) at any site, and only at the WA and NSW sites in period 4 (March to July 2001) was there a response to renovation. As a result, renovation at the NSW site only significantly increased ryegrass utilisation over the whole experimental period.
Ryegrass plant density was higher at the NSW, WA (excluding minimum renovation) and Tas. (excluding full renovation) sites 6 months after renovation but this was only sustained for 12 months for the minimum and medium treatments at the NSW and Tas. sites, respectively, presumably due to reduced competition from naturalised C4 summer grasses [kikuyu (Pennisetum clandestinum) and paspalum (Paspalum dilatatum)] in NSW. At the NSW, WA and SA sites, the original ryegrass plant density was low (<35 plants/m2) compared with the Tas. site where density was around 185/m2.
The response to renovating a degraded perennial ryegrass pasture varied between sites in Australia. Positive responses were generally small and were most consistent where renovation removed competing C4 summer grasses.
Effect of plastic mulch and row covers on photosynthesis and yield of watermelon
Authors: Ibarra-Jiménez L. , Munguía-López J. , Lozano-del Río A. J. , Zermeño-González A.
Published: January 2006

The effect of row covers on watermelon (Citrullus vulgaris) grown on plastic mulch is well documented. However, row covers have not been adequately evaluated under Mexican growing conditions. Watermelon plants were grown on plastic mulch alone or with row covers to study their effect on photosynthesis, and early and total yields. Treatments were clear plastic mulch (C); black plastic mulch (B); B plus a Vispore cover of polypropylene (BV); B plus a white cover of perforated polyethylene (BW); B plus a clear cover of perforated polyethylene (BC); B plus an Agribon cover of polypropylene (BA); and bare soil as the control. For plants grown in treatment C, B or B combined with row covers, plant dry weight and number of leaves 40 days after seeding (DAS) were higher than the control (P<0.05), except BC which was comparable to the control. Total yields of treatments C, B, BV, BW and BA differed (P<0.05) from BC and the control. Total yields increased by 46.1, 43.2, 35.7, 41.6, 13.3, 15.4 and 35.8 t/ha for the C, B, BV, BW, BC and BA treatments, respectively, over the control, which yielded 27.1 t/ha. Total yield was highest for the C and the B treatment suggesting that there was no need for additional covers. The number of leaves per plant or dry weight per plant better explains the changes in yield than net photosynthesis rate. Stomatal conductance was explained in part by changes in photosynthesis.
Selection for fruit removal force and related characteristics in olive breeding progenies
Authors: León L. , de la Rosa R. , Barranco D. , Rallo L.
Published: January 2006

In the present work we discuss the possibility of breeding olives for suitability to mechanical harvesting. Variability in fruit removal force (FRF), and its correlation with fruit weight (FW) and yield were evaluated in reciprocal crosses of ‘Arbequina’, ‘Frantoio’ and ‘Picual’ cultivars. A wide range of variation was observed for FRF among the genotypes evaluated. A high correlation between FRF and FW was observed but not between FRF and yield. Analysis of variance showed significant differences among years but not among female genitors. Differences among genotypes, irrespective of their genitors, were also found, with the variance due to genotype being higher for FRF/FW than for FRF as dependent variable. Correlations of genotype data between years were significant for FRF/FW but not for FRF. The relatively low correlation values indicated that only some negative selection could be done on the basis of FRF/FW at the first stage of the breeding process, owing to the importance of the environmental variability. A more precise evaluation is needed during the successive stages of breeding, where several replicates per genotype are available.
Goitre and iodine deficiency in Afghanistan: a case—control study
Authors: Oberlin Odile , Plantin-Carrenard Emmanuelle , Rigal Odile , Wilkinson Caroline
Published: January 2006

I deficiency is the leading cause of preventable mental retardation. A number of surveys in Afghanistan show goitre prevalence rates more than 20% amongst children and women. Access to iodised salt remains low, with disparate coverage by region, despite the recent implementation of a national salt iodisation programme. The objectives were to identify whether the presence of goitre is a satisfactory marker of I deficiency and to examine the relationship between goitre and thyroid function. A case–control study was carried out in children and women of childbearing age, stratified on the presence of goitre. Adequate levels of urinary I were observed in 6·8% of all the subjects, and amongst the subjects without goitre, this figure was only 9%. The presence of goitre was significantly associated with severe urinary I deficiency; however, the difference between the cases and controls was not as great as expected. An association between the presence of goitre and elevated thyroid-stimulating hormone (TSH) levels was observed, but 14% of the children without palpable goitre also showed abnormal TSH levels.Given that the majority of subjects showed some degree of I deficiency and that children without goitre may have elevated TSH levels, the absence of goitre is an insufficient indicator to determine adequate I status. The risk of subsequent development of goitre, in the currently non-goitre population, is elevated. This suggests that short-term I supplementation should be considered independently of the presence of goitre or urinary I level, until the access to and consumption of iodised salt is generalised.
Taiwanese vegetarians have higher insulin sensitivity than omnivores
Authors: Hung Chien-Jung , Huang Po-Chao , Li Yi-Hwei , Lu Shao-Chun , Ho Low-Tone , Chou Hsu-Fang
Published: January 2006

The present study was designed to examine the effects of habitual consumption of Taiwanese vegetarian diets on hormonal secretion, and on lipid and glycaemic control. Of the ninety-eight healthy female adults recruited from Hualien, Taiwan (aged 31–45 years), forty-nine were Buddhist lactovegetarians and forty-nine were omnivores. Dietary intakes were measured, and blood levels of nutrients and hormones were analysed. Vegetarians consumed less energy, fat and protein, but more fibre than the omnivores. Compared with the omnivores, the vegetarians had, on average, lower BMI and smaller waist circumference. Except for slightly lower levels of thyroxine (T4) in vegetarians, vegetarians and omnivores both showed similar levels of triiodothyronine (T3), free T4, thyroid-stimulating hormone, T3:T4 ratio and cortisol. Compared with the omnivores, the vegetarians had significantly lower levels of fasting insulin (median: 35·3 v. 50·6pmol/l) and plasma glucose (mean: 4·7 (se 0·05) v. 4·9 (se 0·05) mmol/l). Insulin resistance, as calculated by the homeostasis model assessment method, was significantly lower in the vegetarians than in the omnivores (median: 1·10 v. 1·56), while β-cell function was not different between the two groups. BMI and diet were both independent predictors for insulin resistance, and contributed 18 and 15% of the variation in insulin resistance, respectively. In conclusion, Taiwanese vegetarians had lower glucose and insulin levels and higher insulin sensitivity than did the omnivores. Diet and lower BMI were partially responsible for the high insulin sensitivity observed in young Taiwanese vegetarians.
Effect of isomalt consumption on faecal microflora and colonic metabolism in healthy volunteers
Authors: Gostner A. , Blaut M. , Schäffer V. , Kozianowski G. , Theis S. , Klingeberg M. , Dombrowski Y. , Martin D. , Ehrhardt S. , Taras D. , Schwiertz A. , Kleessen B. , Lührs H. , Schauber J. , Dorbath D. , Menzel T. , Scheppach W.
Published: January 2006

Due to its low digestibility in the small intestine, a major fraction of the polyol isomalt reaches the colon. However, little is known about effects on the intestinal microflora. During two 4-week periods in a double-blind, placebo-controlled, cross-over design, nineteen healthy volunteers consumed a controlled basal diet enriched with either 30g isomalt or 30g sucrose daily. Stools were collected at the end of each test phase and various microbiological and luminal markers were analysed. Fermentation characteristics of isomalt were also investigatedin vitro. Microbiological analyses of faecal samples indicated a shift of the gut flora towards an increase of bifidobacteria following consumption of the isomalt diet compared with the sucrose diet (P<0·05). During the isomalt phase, the activity of bacterial β-glucosidase decreased (P<0·05) whereas β-glucuronidase, sulfatase, nitroreductase and urease remained unchanged. Faecal polyamines were not different between test periods with the exception of cadaverine, which showed a trend towards a lower concentration following isomalt (P=0·055). Faecal SCFA, lactate, bile acids, neutral sterols, N, NH3, phenol andp-cresol were not affected by isomalt consumption.In vitro, isomalt was metabolized in several bifidobacteria strains and yielded high butyrate concentrations. Isomalt, which is used widely as a low-glycaemic and low-energy sweetener, has to be considered a prebiotic carbohydrate that might contribute to a healthy luminal environment of the colonic mucosa.
The ketogenic diet in children with epilepsy
Authors: Papandreou D. , Pavlou E. , Kalimeri E. , Mavromichalis I.
Published: January 2006

Children with epilepsy, especially those facing intractable seizures, experience a great impact on the quality of their lives. Effective treatment is essential, and although new anti-epileptic drugs have shown an improved profile of action, still a substantial number of children look for more efficacious ways of treatment that are far away from potential toxicity and ineffectiveness. The ketogenic diet is a dietary therapy for epileptic children based on manipulation of metabolism principles and brain energetics. This regimen aims to produce a controlled ketonaemia through excessive dietary fat intake, little carbohydrates and adequate (for growth) protein. The present paper is a review of previous and current papers regarding the proposed mechanisms of the ketogenic diet’s action, and the efficacy of the regimen on epileptic children. Unfortunately, a few small studies in sample size and duration tried to evaluate the potential risks of this regimen and their results were rather inconclusive. Further research needs to be done in order for the exact mechanism of the ketogenic diet to be clarified which will help to improve the diet’s application, especially for vulnerable epileptic children as far as their growth is concerned.