bluuebunny/crossref_metadata_2025 huggingface dataset:
Field emission properties of electrochemically deposited gold nanowires
Authors: Dangwal A. , Pandey C. S. , Müller G. , Karim S. , Cornelius T. W. , Trautmann C.
Published: February 2008

Field emission properties of vertically aligned gold nanowires of different aspect ratios and spatial distribution are presented. The nanowires were electrochemically deposited into the pores of etched ion-track polymer membranes. High emission site densities up to 5.7×105cm−2 based on a controlled field enhancement β of individual emitting sites were observed by means of field emission scanning microscopy. Local measurements reveal stable Fowler–Nordheim behavior of the emitters up to currents of 100μA. The integral emission of Au nanowires cathodes for device application is also discussed.
Investigation of phase transition of Ge2Sb2Te5 and N-incorporated Ge2Sb2Te5 films using x-ray absorption spectroscopy
Authors: Kim Youngkuk , Jang M. H. , Jeong K. , Cho M.-H. , Do K. H. , Ko D.-H. , Sohn H. C. , Kim Min Gyu
Published: February 2008

For this study, the phase-change materials Ge2Sb2Te5 and N-doped Ge2Sb2Te5 films were investigated using x-ray absorption near-edge structure and extended x-ray absorption fine structure. During the phase transition, change in electronic structure is observed by the shift of the absorption edge energy, i.e., structural coordination of Ge–Te changes from tetrahedral to octahedral coordination, of which the interatomic distances are 3.12 and 2.83Å, respectively. In addition, nitrogen incorporation into the film led to a p-p orbital hybridization and a different crystallization behavior. The hybridization caused by the formation of a Ge–N bond was related to suppression of the phase transition.
Decay dynamics of neutral and charged excitonic complexes in single InAs∕GaAs quantum dots
Authors: Feucker M. , Seguin R. , Rodt S. , Hoffmann A. , Bimberg D.
Published: February 2008

Systematic time-resolved measurements on neutral and charged excitonic complexes (X, XX, X+, and XX+) of 26 different single InAs∕GaAs quantum dots are reported. The ratios of the decay times are discussed in terms of the number of transition channels determined by the excitonic fine structure and a specific transition time for each channel. The measured ratio for the neutral complexes is 1.7 deviating from the theoretically predicted value of 2. A ratio of 1.5 for the positively charged exciton and biexciton decay time is predicted and exactly matched by the measured ratio indicating identical specific transition times for the transition channels involved.
Molecular orientation dependent interfacial dipole at the F16CuPc∕CuPc organic heterojunction interface
Authors: Chen Wei , Chen Shi , Huang Han , Qi Dong Chen , Gao Xing Yu. , Wee Andrew Thye Shen
Published: February 2008

In situ synchrotron-based near-edge x-ray absorption fine structure measurements and photoemission spectroscopy have been used to investigate the effect of molecular orientation on the interfacial dipole and the energy level alignment at the interfaces of organic heterojunctions comprising copper-hexadecafluoro-phthalocyanine (F16CuPc) on both standing-up and lying-down copper(II) phthalocyanine (CuPc) thin films. It is found that F16CuPc thin films adopt the same molecular orientation of the underlying CuPc thin films. An interfacial dipole of 0.45eV forms at the interface of lying-down F16CuPc∕CuPc on highly ordered pyrolytic graphite. In contrast, a much larger interfacial dipole of 1.35eV appears at the interface of standing-up F16CuPc∕CuPc on octane-1-thiol terminated Au(111).
High work function materials for source/drain contacts in printed polymer thin film transistors
Authors: Sholin V. , Carter S. A. , Street R. A. , Arias A. C.
Published: February 2008

Studies of materials for source-drain electrodes in ink-jet printed polymer-based thin film transistors (TFTs) are reported. Two systems are studied: a blend of Ag nanoparticles with poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and an ethylene glycol-doped PEDOT:PSS solution (modified-PEDOT). The semiconductor used is the polythiophene derivative poly [5,5′-bis(3-dodecyl-2-thienyl)-2,2,2′-bithiophene]. PEDOT:Ag blends and modified-PEDOT yield TFTs with mobilities around 10−2 and 10−3cm2∕Vs, respectively, subthreshold slopes around 1.6V/decade and on-to-off current ratios of 106–107. Both systems show considerable improvement over printed TFTs with Ag nanoparticle source-drain electrodes. Results on film resistivity and morphology are discussed along with device characteristic analysis.
Dielectric response and structure of in-plane tensile strained BaTiO3 thin films grown on the LaNiO3 buffered Si substrate
Authors: Qiao Liang , Bi Xiaofang
Published: February 2008

Highly (001)-textured BaTiO3 films were grown epitaxially on the LaNiO3 buffered Si substrate. A strong in-plane tensile strain has been revealed by using x-ray diffraction and high resolution transmission electron microscopy. The BaTiO3 film has exhibited a small remnant polarization, indicating the presence of ca1∕ca2∕ca1∕ca2 polydomain state in the film. Temperature dependent dielectric permittivity has demonstrated that two phase transitions occurred at respective temperatures of 170 and 30°C. The result was discussed in detail based on the misfit strain-temperature phase diagrams theory.
Improvement in C-V characteristics of Ge metal-oxide semiconductor capacitor by H2O2 incorporated HCl pretreatment
Authors: Kamata Yoshiki , Ino Tsunehiro , Koyama Masato , Nishiyama Akira
Published: February 2008

Electrical characteristics of high-κ∕Ge metal-oxide semiconductor (MOS) capacitors pretreated with HCl or HF solutions are investigated, including the effect of H2O2 incorporation. HCl treatment is more effective than HF treatment for decreasing equivalent oxide thickness. H2O2 incorporation into HCl solution leads to dramatic decrease in the capacitance at inversion side. We have confirmed that residual metal impurities are reduced below 1010atoms∕cm2 on the Ge surface after pretreatment with mixed solution of HCl and H2O2. We conclude that decrease in metal impurities at Ge surface is responsible for the superior C-V characteristic of Ge MOS capacitor.
Piezoresistive properties of carbon nanotubes under radial force investigated by atomic force microscopy
Authors: Nishio Taichi , Miyato Yuji , Kobayashi Kei , Matsushige Kazumi , Yamada Hirofumi
Published: February 2008

We investigated the piezoresistive properties of single-wall carbon nanotubes (SWCNTs) under the tip-induced force in the radial direction using atomic force microscopy. We found that the conductance of the bundled SWCNTs was modulated by the applied radial force. The polarity and amount of the conductance change were different on every bundle and even dependent on the location where the force was applied. These phenomena were explained by the modulation of the band structures of the SWCNTs, which was caused by the deformation at the critical pressure.
Effect on nitrogen acceptor as Mg is alloyed into ZnO
Authors: Gai Y. Q. , Yao B. , Wei Z. P. , Li Y. F. , Lu Y. M. , Shen D. Z. , Zhang J. Y. , Zhao D. X. , Fan X. W. , Li Jingbo , Xia Jian-Bai
Published: February 2008

Our Raman measurement indicates that the intensity of the peaks (510 and 645cm−1) related to nitrogen concentration is enhanced in MgZnO compared with that in ZnO. Using first-principles band structure methods, we calculated the formation energy and transition energy level for nitrogen acceptor in ZnO and random MgxZn1−xO (with x=0.25) alloy. Our calculations show that the incorporation of nitrogen can be enhanced as Mg is alloyed into ZnO, which agrees with our experiments. The acceptor energy level deeper in the alloy ascribes to the downward shift of the valence-band maximum edge in the presence of magnesium.
High quality nanoelectromechanical microwave resonator based on a carbon nanotube array
Authors: Dragoman M. , Neculoiu D. , Cismaru A. , Dragoman D. , Grenier K. , Pacchini S. , Mazenq L. , Plana R.
Published: February 2008

A brushlike array of metallic carbon nanotubes is integrated in a trench etched in a silicon substrate and terminated with two coplanar lines. When the incoming microwave signal frequency is equal to the mechanical resonance frequency of the nanotubes forming the array, a deep and narrow notch is formed in the microwave frequency response of the array, indicating that the array is acting like a resonator. The quality factor of the array at the fundamental resonance frequency of 1.4GHz is around 800 at room temperature.
Efficient energy extraction from large-mode-area, short, heavily Er:Yb codoped phosphate-glass fiber for pulsed laser applications
Authors: Polynkin Pavel , Peyghambarian N. , Moloney Jerome
Published: February 2008

Experimental demonstration of an efficient energy extraction from heavily Er:Yb codoped phosphate-glass fiber is reported. In our experiments, sub-20-ns pulses at 1.5μm wavelength produced by an actively Q-switched all-fiber oscillator are amplified in 15cm long, side-pumped phosphate fiber doped with 1wt% of Er2O3 and 8wt% of Yb2O3. Two types of active fiber are used, with core diameters of 14 and 25μm. The pulse energy achieved with these fibers is 105 and 215μJ, respectively, with nearly diffraction-limited beam quality. These experiments indicate a potential for further energy scaling beyond the millijoule level by increasing the core size of the fiber.
Large sensitive-area NbN nanowire superconducting single-photon detectors fabricated on single-crystal MgO substrates
Authors: Miki Shigehito , Fujiwara Mikio , Sasaki Masahide , Baek Burm , Miller Aaron J. , Hadfield Robert H. , Nam Sae Woo , Wang Zhen
Published: February 2008

We report on the performance of large area NbN nanowire superconducting single-photon detectors (SSPDs). 20×20μm2 area SSPDs with 80 and 100nm linewidths and 50% fill factor were fabricated in 4-nm-thick NbN films grown on single-crystal MgO substrates. The high quality of the devices was verified by electrical and optical testing and compares favorably to measurements of 10×10μm2 area SSPDs. Measurements of kinetic inductance versus bias current indicate that the constriction density is low. The fiber-coupled detection efficiency of the devices was 0.4%–3.5% at 100Hz dark count rate.
Nitric acid pretreatment for the passivation of boron emitters for n-type base silicon solar cells
Authors: Mihailetchi Valentin D. , Komatsu Yuji , Geerligs L. J.
Published: February 2008

We have developed a simple method to passivate industrially produced boron-doped emitters for n-type base silicon solar cells using an ultrathin (∼1.5nm) silicon dioxide layer between the silicon emitter and the silicon nitride antireflection coating film. This ultrathin oxide is grown at room temperature by soaking the silicon wafers in a solution of nitric acid prior to the deposition of the silicon nitride antireflection coating film. The n-type solar cells processed in such a way demonstrate a conversion efficiency enhancement of more than 2% absolute over the solar cells passivated without the silicon dioxide layer.
Oscillating wave sensor based on the Goos–Hänchen effect
Authors: Wang Yi , Li Honggen , Cao Zhuangqi , Yu Tianyi , Shen Qishun , He Ying
Published: February 2008

Instead of the evanescent field sensors, an oscillating wave sensor based on the Goos–Hänchen effect is proposed in this letter. It is demonstrated that as the intrinsic damping is well-matched with the radiative damping of the ultrahigh-order modes in a symmetrical metal-cladding waveguide with submillimeter scale, the enormously enhanced lateral beam shift results in a very high sensitivity of the sensor.
Rectifying property and magnetocapacitance in multiferroic p-n junction
Authors: Yang J. J. , Guo S. M. , Luo L. B. , Xiong C. M. , Zhao Y. G. , He Y. J.
Published: February 2008

Multiferroic p-n junctions were fabricated by growing La0.1Bi0.9MnO3 films on Nb–SrTiO3 using pulsed laser deposition. The current-voltage curves of the junction show good rectifying property. Both the ferroelectric transition and ferromagnetic transition of La0.1Bi0.9MnO3 have remarkable influence on the transport properties of the junction. A large positive magnetocapacitance was also observed in this junction. Analysis suggests that the property of La0.1Bi0.9MnO3∕Nb–SrTiO3 is dominated by the property of La0.1Bi0.9MnO3. This work demonstrates that multiferroic p-n junctions possess some interesting properties that may be useful for future applications.
Generation of human induced pluripotent stem cells from dermal fibroblasts
Authors: Lowry W. E. , Richter L. , Yachechko R. , Pyle A. D. , Tchieu J. , Sridharan R. , Clark A. T. , Plath K.
Published: February 2008

The generation of patient-specific pluripotent stem cells has the potential to accelerate the implementation of stem cells for clinical treatment of degenerative diseases. Technologies including somatic cell nuclear transfer and cell fusion might generate such cells but are hindered by issues that might prevent them from being used clinically. Here, we describe methods to use dermal fibroblasts easily obtained from an individual human to generate human induced pluripotent stem (iPS) cells by ectopic expression of the defined transcription factors
KLF4
,
OCT4
,
SOX2
, and
C-MYC
. The resultant cell lines are morphologically indistinguishable from human embryonic stem cells (HESC) generated from the inner cell mass of a human preimplantation embryo. Consistent with these observations, human iPS cells share a nearly identical gene-expression profile with two established HESC lines. Importantly, DNA fingerprinting indicates that the human iPS cells were derived from the donor material and are not a result of contamination. Karyotypic analyses demonstrate that reprogramming of human cells by defined factors does not induce, or require, chromosomal abnormalities. Finally, we provide evidence that human iPS cells can be induced to differentiate along lineages representative of the three embryonic germ layers indicating the pluripotency of these cells. Our findings are an important step toward manipulating somatic human cells to generate an unlimited supply of patient-specific pluripotent stem cells. In the future, the use of defined factors to change cell fate may be the key to routine nuclear reprogramming of human somatic cells.
Females increase current reproductive effort when future access to males is uncertain
Authors: Heubel Katja U , Lindström Kai , Kokko Hanna
Published: February 2008

Trade-offs between current and future reproduction shape life histories of organisms, e.g. increased mortality selects for earlier reproductive effort, and mate limitation has been shown to shape male life histories. Here, we show that female life histories respond adaptively to mate limitation. Female common gobies (
Pomatoschistus microps
) respond to a female-biased operational sex ratio by strongly increasing the size of their first clutch. The plastic response is predicted by a model that assumes that females use the current competitive situation to predict future difficulties of securing a mating. Because female clutch size decisions are much more closely linked to population dynamics than male life-history traits, plastic responses to mate-finding limitations may be an underappreciated force in population dynamics.
Genomic expression of mesenchymal stem cells to altered nanoscale topographies
Authors: Dalby Matthew J , Andar Abhay , Nag Abhijit , Affrossman Stanley , Tare Rahul , McFarlane Sara , Oreffo Richard O.C
Published: February 2008

The understanding of cellular response to the shape of their environment would be of benefit in the development of artificial extracellular environments for potential use in the production of biomimetic surfaces. Specifically, the understanding of how cues from the extracellular environment can be used to understand stem cell differentiation would be of special interest in regenerative medicine.

In this paper, the genetic profile of mesenchymal stem cells cultured on two osteogenic nanoscale topographies (pitted surface versus raised islands) are compared with cells treated with dexamethasone, a corticosteroid routinely used to stimulate bone formation in culture from mesenchymal stem cells, using 19k gene microarrays as well as 101 gene arrays specific for osteoblast and endothelial biology.

The current studies show that by altering the shape of the matrix a cell response (genomic profile) similar to that achieved with chemical stimulation can be elicited. Here, we show that bone formation can be achieved with efficiency similar to that of dexamethasone with the added benefit that endothelial cell development is not inhibited. We further show that the mechanism of action of the topographies and dexamethasone differs. This could have an implication for tissue engineering in which a simultaneous, targeted, development of a tissue, such as bone, without the suppression of angiogenesis to supply nutrients to the new tissue is required. The results further demonstrate that perhaps the shape of the extracellular matrix is critical to tissue development.
Socially informed random walks: incorporating group dynamics into models of population spread and growth
Authors: Haydon Daniel T , Morales Juan M , Yott Adelle , Jenkins Deborah A , Rosatte Rick , Fryxell John M
Published: February 2008

Simple correlated random walk (CRW) models are rarely sufficient to describe movement of animals over more than the shortest time scales. However, CRW approaches can be used to model more complex animal movement trajectories by assuming individuals move in one of several different behavioural or movement states, each characterized by a different CRW. The spatial and social context an individual experiences may influence the proportion of time spent in different movement states, with subsequent effects on its spatial distribution, survival and fecundity. While methods to study habitat influences on animal movement have been previously developed, social influences have been largely neglected. Here, we fit a ‘socially informed’ movement model to data from a population of over 100 elk (
Cervus canadensis
) reintroduced into a new environment, radio-collared and subsequently tracked over a 4-year period. The analysis shows how elk move further when they are solitary than when they are grouped and incur a higher rate of mortality the further they move away from the release area. We use the model to show how the spatial distribution and growth rate of the population depend on the balance of fission and fusion processes governing the group structure of the population. The results are briefly discussed with respect to the design of species reintroduction programmes.
Contrasting effects of anthropogenic and natural acidity in streams: a meta-analysis
Authors: Petrin Zlatko , Englund Göran , Malmqvist Björn
Published: February 2008

Large-scale human activities including the extensive combustion of fossil fuels have caused acidification of freshwater systems on a continental scale, resulting in reduced species diversity and, in some instances, impaired ecological functioning. In regions where acidity is natural, however, species diversity and functioning seem to be less affected. This contrasting response is likely to have more than one explanation including the possibility of adaptation in organisms exposed to natural acidity over evolutionary time scales and differential toxicity due to dissimilarities in water chemistry other than pH. However, empirical evidence supporting these hypotheses is equivocal. Partly, this is because previous research has mainly been conducted at relatively small geographical scales, and information on ecological functioning in this context is generally scarce. Our goal was to test whether anthropogenic acidity has stronger negative effects on species diversity and ecological functioning than natural acidity. Using a meta-analytic approach based on 60 datasets, we show that macroinvertebrate species richness and the decomposition of leaf litter—an important process in small streams—tend to decrease with increasing acidity across regions and across both the acidity categories. Macroinvertebrate species richness, however, declines three times more rapidly with increasing acidity where it is anthropogenic than where it is natural, in agreement with the adaptation hypothesis and the hypothesis of differences in water chemistry. By contrast, the loss in ecological functioning differs little between the categories, probably because increases in the biomass of taxa remaining at low pH compensate for losses in functionality that would otherwise accompany losses of taxa from acidic systems. This example from freshwater acidification illustrates how natural and anthropogenic stressors can differ markedly in their effects on species diversity and one aspect of ecological functioning.
Hydro-climatic and ecological behaviour of the drought of Amazonia in 2005
Authors: Marengo J.A , Nobre C.A , Tomasella J , Cardoso M.F , Oyama M.D
Published: February 2008

In 2005, southwestern Amazonia experienced the effects of an intense drought that affected life and biodiversity. Several major tributaries as well as parts of the main river itself contained only a fraction of their normal volumes of water, and lakes were drying up. The consequences for local people, animals and the forest itself are impossible to estimate now, but they are likely to be serious. The analyses indicate that the drought was manifested as weak peak river season during autumn to winter as a consequence of a weak summertime season in southwestern Amazonia; the winter season was also accompanied by rainfall that sometimes reached 25% of the climatic value, being anomalously warm and dry and helping in the propagation of fires. Analyses of climatic and hydrological records in Amazonia suggest a broad consensus that the 2005 drought was linked not to El Niño as with most previous droughts in the Amazon, but to warming sea surface temperatures in the tropical North Atlantic Ocean.
Road building, land use and climate change: prospects for environmental governance in the Amazon
Authors: Perz Stephen , Brilhante Silvia , Brown Foster , Caldas Marcellus , Ikeda Santos , Mendoza Elsa , Overdevest Christine , Reis Vera , Reyes Juan Fernando , Rojas Daniel , Schmink Marianne , Souza Carlos , Walker Robert
Published: February 2008

Some coupled land–climate models predict a dieback of Amazon forest during the twenty-first century due to climate change, but human land use in the region has already reduced the forest cover. The causation behind land use is complex, and includes economic, institutional, political and demographic factors. Pre-eminent among these factors is road building, which facilitates human access to natural resources that beget forest fragmentation. While official government road projects have received considerable attention, unofficial road building by interest groups is expanding more rapidly, especially where official roads are being paved, yielding highly fragmented forest mosaics. Effective governance of natural resources in the Amazon requires a combination of state oversight and community participation in a ‘hybrid’ model of governance. The MAP Initiative in the southwestern Amazon provides an example of an innovative hybrid approach to environmental governance. It embodies a polycentric structure that includes government agencies, NGOs, universities and communities in a planning process that links scientific data to public deliberations in order to mitigate the effects of new infrastructure and climate change.
An objective tropical Atlantic sea surface temperature gradient index for studies of south Amazon dry-season climate variability and change
Authors: Good Peter , Lowe Jason A , Collins Mat , Moufouma-Okia Wilfran
Published: February 2008

Future changes in meridional sea surface temperature (SST) gradients in the tropical Atlantic could influence Amazon dry-season precipitation by shifting the patterns of moisture convergence and vertical motion. Unlike for the El Niño-Southern Oscillation, there are no standard indices for quantifying this gradient. Here we describe a method for identifying the SST gradient that is most closely associated with June–August precipitation over the south Amazon. We use an ensemble of atmospheric general circulation model (AGCM) integrations forced by observed SST from 1949 to 2005. A large number of tropical Atlantic SST gradient indices are generated randomly and temporal correlations are examined between these indices and June–August precipitation averaged over the Amazon Basin south of the equator. The indices correlating most strongly with June–August southern Amazon precipitation form a cluster of near-meridional orientation centred near the equator. The location of the southern component of the gradient is particularly well defined in a region off the Brazilian tropical coast, consistent with known physical mechanisms. The chosen index appears to capture much of the Atlantic SST influence on simulated southern Amazon dry-season precipitation, and is significantly correlated with observed southern Amazon precipitation.

We examine the index in 36 different coupled atmosphere–ocean model projections of climate change under a simple compound 1% increase in CO2. Within the large spread of responses, we find a relationship between the projected trend in the index and the Amazon dry-season precipitation trends. Furthermore, the magnitude of the trend relationship is consistent with the inter-annual variability relationship found in the AGCM simulations. This suggests that the index would be of use in quantifying uncertainties in climate change in the region.
Human dimensions of climate change: the vulnerability of small farmers in the Amazon
Authors: Brondizio Eduardo S , Moran Emilio F
Published: February 2008

This paper argues for a twofold perspective on human adaptation to climate change in the Amazon. First, we need to understand the processes that mediate perceptions of environmental change and the behavioural responses at the levels of the individual and the local population. Second, we should take into account the process of production and dissemination of global and national climate information and models to regional and local populations, especially small farmers. We discuss the sociocultural and environmental diversity of small farmers in the Amazon and their susceptibility to climate change associated with drought, flooding and accidental fire. Using survey, ethnographic and archival data from study areas in the state of Pará, we discuss farmers' sources of knowledge and long-term memory of climatic events, drought and accidental fire; their sources of climate information; their responses to drought and fire events and the impact of changing rainfall patterns on land use. We highlight the challenges of adaptation to climate change created by the influence of migration and family turnover on collective action and memory, the mismatch of scales used to monitor and disseminate climate data and the lack of extension services to translate large-scale forecasts to local needs. We found that for most farmers, memories of extended drought tend to decrease significantly after 3 years. Over 50% of the farmers interviewed in 2002 did not remember as significant the El Niño Southern Oscillation (ENSO) drought of 1997/1998. This helps explain why approximately 40% of the farmers have not changed their land-use behaviours in the face of the strongest ENSO event of the twentieth century.
Interactions between rainfall, deforestation and fires during recent years in the Brazilian Amazonia
Authors: Aragão Luiz Eduardo O.C , Malhi Yadvinder , Barbier Nicolas , Lima Andre , Shimabukuro Yosio , Anderson Liana , Saatchi Sassan
Published: February 2008

Understanding the interplay between climate and land-use dynamics is a fundamental concern for assessing the vulnerability of Amazonia to climate change. In this study, we analyse satellite-derived monthly and annual time series of rainfall, fires and deforestation to explicitly quantify the seasonal patterns and relationships between these three variables, with a particular focus on the Amazonian drought of 2005. Our results demonstrate a marked seasonality with one peak per year for all variables analysed, except deforestation. For the annual cycle, we found correlations above 90% with a time lag between variables. Deforestation and fires reach the highest values three and six months, respectively, after the peak of the rainy season. The cumulative number of hot pixels was linearly related to the size of the area deforested annually from 1998 to 2004 (r2=0.84,p=0.004). During the 2005 drought, the number of hot pixels increased 43% in relation to the expected value for a similar deforested area (approx. 19 000 km2). We demonstrated that anthropogenic forcing, such as land-use change, is decisive in determining the seasonality and annual patterns of fire occurrence. Moreover, droughts can significantly increase the number of fires in the region even with decreased deforestation rates. We may expect that the ongoing deforestation, currently based on slash and burn procedures, and the use of fires for land management in Amazonia will intensify the impact of droughts associated with natural climate variability or human-induced climate change and, therefore, a large area of forest edge will be under increased risk of fires.
Effects of large-scale Amazon forest degradation on climate and air quality through fluxes of carbon dioxide, water, energy, mineral dust and isoprene
Authors: Betts Richard , Sanderson Michael , Woodward Stephanie
Published: February 2008

Loss of large areas of Amazonian forest, through either direct human impact or climate change, could exert a number of influences on the regional and global climates. In the Met Office Hadley Centre coupled climate–carbon cycle model, a severe drying of this region initiates forest loss that exerts a number of feedbacks on global and regional climates, which magnify the drying and the forest degradation. This paper provides an overview of the multiple feedback process in the Hadley Centre model and discusses the implications of the results for the case of direct human-induced deforestation. It also examines additional potential effects of forest loss through changes in the emissions of mineral dust and biogenic volatile organic compounds. The implications of ecosystem–climate feedbacks for climate change mitigation and adaptation policies are also discussed.
Effects of rising temperatures and [CO
2
] on the physiology of tropical forest trees
Authors: Lloyd Jon , Farquhar Graham D
Published: February 2008

Using a mixture of observations and climate model outputs and a simple parametrization of leaf-level photosynthesis incorporating known temperature sensitivities, we find no evidence for tropical forests currently existing ‘dangerously close’ to their optimum temperature range. Our model suggests that although reductions in photosynthetic rate at leaf temperatures (
T
L
) above 30°C may occur, these are almost entirely accountable for in terms of reductions in stomatal conductance in response to higher leaf-to-air vapour pressure deficits
D
. This is as opposed to direct effects of
T
L
on photosynthetic metabolism. We also find that increases in photosynthetic rates associated with increases in ambient [CO
2
] over forthcoming decades should more than offset any decline in photosynthetic productivity due to higher
D
or
T
L
or increased autotrophic respiration rates as a consequence of higher tissue temperatures. We also find little direct evidence that tropical forests should not be able to respond to increases in [CO
2
] and argue that the magnitude and pattern of increases in forest dynamics across Amazonia observed over the last few decades are consistent with a [CO
2
]-induced stimulation of tree growth.
Water recycling by Amazonian vegetation: coupled versus uncoupled vegetation–climate interactions
Authors: Cowling S.A , Shin Y , Pinto E , Jones C.D
Published: February 2008

To demonstrate the relationship between Amazonian vegetation and surface water dynamics, specifically, the recycling of water via evapotranspiration (ET), we compare two general circulation model experiments; one that couples the IS92a scenario of future CO
2
emissions to a land-surface scheme with dynamic vegetation (coupled) and the other to fixed vegetation (uncoupled). Because the only difference between simulations involves vegetation coupling, any alterations to surface energy and water balance must be due to vegetation feedbacks. The proportion of water recycled back to the atmosphere is relatively conserved through time for both experiments. Absolute value of recycled water is lower in our coupled relative to our uncoupled simulation as a result of increasing atmospheric CO
2
that in turn promotes lowering of stomatal conductance and increase in water-use efficiency. Bowen ratio increases with decreasing per cent broadleaf cover, with the greatest rate of change occurring at high vegetation cover (above 70% broadleaf cover). Over the duration of the climate change simulation, precipitation is reduced by an extra 30% in the coupled relative to the uncoupled simulations. Lifting condensation level (proxy for base height of cumulus cloud formation) is 520 m higher in our coupled relative to uncoupled simulations.
Improving concept‐based web image retrieval by mixing semantically similar Greek queries
Authors: Lazarinis Fotis
Published: February 2008

Purpose

Image searching is a common activity for web users. Search engines offer image retrieval services based on textual queries. Previous studies have shown that web searching is more demanding when the search is not in English and does not use a Latin‐based language. The aim of this paper is to explore the behaviour of the major search engines in image retrieval using Greek text queries and to present and evaluate an image metaseacher that combines semantically similar queries to improve the relevance in image retrieval.

Design/methodology/approach

Initially the image retrieval capabilities (based on the number of items retrieved and their relevance) of search engines in Greek queries is studied with a number of semantically similar queries which differ in morphology. Then a system that produces semantically similar queries and merges their results is presented and the increase in relevance is measured. For the purpose of this paper, a number of queries suggested by a few students are run through the presented metasearcher and directly in the search engines. The participants of the evaluation study measured the precision in both cases.

Findings

The initial evaluation revealed that search engines retrieve different results in queries that differ in morphology or in grammar but still express exactly the same information need. Omission of diacritics affects the retrieval negatively as well. The study showed that the number of relevant images increases by combining the results of queries that differ in morphology.

Originality/value

The findings of this study could be applicable to other complex non‐Latin languages based, for example, on the Cyrillic alphabet. The presented metasearcher is a framework on how to expand the image retrieval capabilities of existing search engines. Its modular nature allows the straightforward integration of other techniques that are tailored to the characteristics of specific natural languages.
Comparison of Wikipedia and other encyclopedias for accuracy, breadth, and depth in historical articles
Authors: Holman Rector Lucy
Published: February 2008

Purpose

This paper seeks to provide reference librarians and faculty with evidence regarding the comprehensiveness and accuracy of Wikipedia articles compared with respected reference resources.

Design/methodology/approach

This content analysis evaluated nine Wikipedia articles against comparable articles in Encyclopaedia Britannica, The Dictionary of American History and American National Biography Online in order to compare Wikipedia's comprehensiveness and accuracy. The researcher used a modification of a stratified random sampling and a purposive sampling to identify a variety of historical entries and compared each text in terms of depth, accuracy, and detail.

Findings

The study did reveal inaccuracies in eight of the nine entries and exposed major flaws in at least two of the nine Wikipedia articles. Overall, Wikipedia's accuracy rate was 80 percent compared with 95‐96 percent accuracy within the other sources. This study does support the claim that Wikipedia is less reliable than other reference resources. Furthermore, the research found at least five unattributed direct quotations and verbatim text from other sources with no citations.

Research limitations/implications

More research must be undertaken to analyze Wikipedia entries in other disciplines in order to judge the source's accuracy and overall quality. This paper also shows the need for analysis of Wikipedia articles' histories and editing process.

Practical implications

This research provides a methodology for further content analysis of Wikipedia articles.

Originality/value

Although generalizations cannot be made from this paper alone, the paper provides empirical data to support concerns regarding the accuracy and authoritativeness of Wikipedia.
Drive‐by BI
Authors: Arant‐Kaspar Wendi , Benefiel Candace
Published: February 2008

Purpose

This paper seeks to describe a program that provides quick and relevant library instruction and research support for teaching faculty and their students within the context of the classroom.

Design/methodology/approach

The paper identifies the pressures on teaching faculty to improve critical inquiry and to conform with the state requirements and demands of future employers as providing an opportunity for academic librarians to present library instruction as a win‐win solution, consistent with library priorities in supporting research and promoting information literacy.

Findings

This project describes a strategy for implementing a drive‐by BI mini‐session, including identifying key courses and faculty, contacting them, positioning the drive‐by BI opportunity for the best effect and impact, and following up with the faculty and students.

Practical implications

This approach is particularly useful for librarians who are striving to reach teaching faculty and, through them, students with the benefits of information literacy, library support and research methods.

Originality/value

This paper describes a proactive approach to library instruction, one that acknowledges the demands upon and goals of both students and faculty in the classroom.
Partnering and programming for undergraduate honors students
Authors: Fraser Riehle Catherine
Published: February 2008

Purpose

This paper sets out to describe successful partnerships between Purdue University Libraries' faculty and directors of undergraduate honors programs. By reporting the results and implications of these collaborations and sharing effective approaches for building new partnerships, the author hopes to provide ideas and suggestions for others considering similar collaborations and services.

Design/methodology/approach

During the 2006/2007 academic year, the Instructional Outreach Librarian at Purdue University, West Lafayette, began partnering with directors of honors programs and consequently implemented new services for undergraduate honors students. The paper cites examples, including one pilot program in particular – a research workshop for freshmen honors students in the College of Liberal Arts. Also included are recommendations and effective approaches for partnership building, survey results, and plans for future programming and services.

Findings

These partnerships have strengthened the Libraries' visibility and effectiveness in preparing undergraduate honors students for college‐level research and lifelong learning. Though frequent communication and an invested recognition of shared goals is essential, partnerships between librarians and honors programs directors are a natural fit, as both groups work towards undergraduate learning and academic achievement.

Practical implications

Partnering and collaborating with groups outside the library contributes to the effectiveness of library services. This is particularly the case for environments where a naturally broad opportunity may not exist, as is the case at Purdue University, which lacks a core curriculum and information literacy requirement. The efforts described in this paper are transferable and could serve as useful models for librarians considering similar partnerships and programs.

Originality/value

Advocating libraries and the importance of information literacy skills is essential in today's digital information age. Reaching out to potential users and partnering with relevant groups and individuals in the community are invaluable in making known the Libraries' mission and importance.
Coordinated action in reverse distribution systems
Authors: Flygansvær Bente M. , Gadde Lars‐Erik , Haugland Sven A.
Published: February 2008

Purpose

The purpose of this paper is to address the prerequisites for achieving coordinated action in reverse distribution systems. It is an underlying assumption in distribution, logistics and supply chain management that a higher level of coordination between the actors is superior to a lower, and a higher levels of coordination will in turn lead to increased performance. Coordination requires the actors to implement efficient coordination mechanisms. The separate distribution flows need to be coordinated individually with appropriate coordination mechanisms. Furthermore, actors need to pay close attention to how different coordination mechanisms co‐exist in order to achieve a higher level of coordinated action and superior system performance.

Design/methodology/approach

The paper is based on a comparative case study of reverse distribution systems for electrical and electronic products in Norway.

Findings

The empirical results indicate that lack of coordination across flows increases costs and reduces the service level, and a low level of coordinated action is achieved. In contrast, it is also found that well functioning coordination mechanisms across flows decrease costs and increase the level of service, indicating that coordinated action is achieved. It is also found that end‐user characteristics are driving forces leading to different types of reverse distribution systems.

Originality/value

The paper builds an important bridge between separate flows in distribution systems, and addresses a void in distribution research.
Evaluation of a school‐linked program for children with cancer
Authors: St Leger Pamela , Campbell Lyn
Published: February 2008

Purpose

The purpose of this paper is to show that the “Back on Track” program is designed to support students with a chronic illness (usually cancer) to maintain contact with their school and peers whilst undergoing treatment, to promote socio‐emotional wellbeing and to facilitate the ease of return to school when they are well. An evaluation of the program occurred in its first year.

Design/methodology/approach

A clarificative evaluation approach was used. This involved collecting data about the elements of the program design and implementation to understand and make explicit the logic of the program. It comprised three stages: documenting the program design; gathering stakeholder feedback about the experiences in the program; and reviewing the program logic of the design and implementation approaches.

Findings

The program (“Back on Track”) actively engaged teachers, parents, students and Program staff in negotiating strategies to keep the students (patients) connected with their school and peers whilst undergoing hospital‐based treatment for their chronic condition, in this case cancer, and when recovering at home before a full return to school. Difficulties emerged with the use of Information Communication Technologies (ICTs) as one of the key program components in keeping the students connected. There were also differences in views between the Program staff, schoolteachers and some of the students and their parents about the ongoing role of the Program once students had returned to school.

Originality/value

The paper indicates what is needed to enhance the implementation and success of programs such as “Back on Track” for this group of young people who have significant chronic illnesses, which necessitate prolonged absences from school and separation from peers.
Fall fare: the NISO ERM Forum
Authors: Medeiros Norm
Published: February 2008

Purpose

The purpose of this article is to describe highlights from the NISO ERM Forum held September 2007 in Denver, Colorado.

Design/methodology/approach

The article notes key areas from the conference, gleaned from speaker comments, audience feedback, and conversations with attendees.

Findings

The biggest impediment to successful e‐resource management is lack of sufficient staffing.

Originality/value

This article provides a current view on the issues surrounding electronic resource management activities and ERMS deployment.
Weaving the digital library web
Authors: Fox Robert
Published: February 2008

Purpose

This column seeks to recommend five basic principles that should be used when a library web site is designed or refactored.

Design/methodology/approach

Explores the options available when creating or redesigning a library web site

Findings

This column is simply exploratory, and examines issues surrounding the initial design or re‐design of a library web site.

Practical implications

The design of a library web site should take into account these five principles as they are outlined in this column, and those principles include: simplicity, user centered design, findability, web standards and accessibility.

Originality/value

This column suggests five principles that will assist librarians and library technology workers in designing better web sites which follow usability principles, web standards and accessibility guidelines. This will hopefully improve the quality of library web based resources and services.