bluuebunny/crossref_metadata_2025 huggingface dataset:
RECAST THE DICE AND ITS POLICY RECOMMENDATIONS
Authors: Rezai Armon
Published: November 2010

The DICE (for Dynamic Integrated model of Climate and the Economy) introduced two important policy aspects to the economic discussion of global warming. First, it argues for a “climate-policy ramp” that deems back-loading of mitigation optimal. Second, it demonstrates that an intergenerational tradeoff is at the heart of the mitigation problem. In this paper we argue that both of these findings rest on contestable assumptions. To demonstrate this a recast DICE is presented. Its outcomes show that DICE's predictions are not robust with higher migitations earlier on and slower temperature increases along the optimal path. The adoption of a baseline scenario in which pollution is a negative externality makes mitigating climate change a Pareto improvement. The alleged sacrifice of present generations vanishes. This strengthens the case for immediate policy action.
The matter with emotions
Authors: Kus Susan
Published: November 2010

I ‘full-heartedly’ agree with Harris and Sørensen that archaeologists are in need of fuller ‘appreciation of how the encounter with the material world is inherently affective’ in order to more effectively understand ‘how human beings and material things are co-constitutive’ (p. 146). Further, but assuredly not ‘foolhardily’, I would argue that in refining our appreciation and understanding of these matters of matter and emotion and being, we can make an important contribution to contemporary dialogues on emotion beyond ‘archaeological dialogues’; in particular, dialogues with psychological anthropologists.
Those obscure objects of desire
Authors: Smith Adam T.
Published: November 2010

‘Everyday life is a life lived on the level of surging affects’, posits Kathleen Stewart in her challenging experimental ethnography Ordinary affects (2007). Affects – public feelings that put intimate sentiments in broad circulation – are, for Stewart, the sinews of social life, an opaque circuit that simultaneously grounds experience in places and things and publicizes the personal. As such, affects are quintessentially archaeological in that they are both artefactual, embedded in what Bill Brown (2003) calls the ‘object matter’ of human relationships, and rooted in deep histories of material production and transformation. It is not surprising, then, that the intertwined problems of emotion and affect have re-emerged as potentially productive loci of research within archaeology itself. Indeed, as the discipline continues to extend its understanding of the social instrumentality of objects, landscapes and representations, it must, of necessity, come to terms with the affective efficacy of things, with the causes and consequences of our captivation.
Pale reflections
Authors: Tarlow Sarah
Published: November 2010

Harris and Sørensen's paper is a welcome attempt to address the question of ‘finding’ and interpreting emotion in the deep past. Their contribution to this emerging area of debate is particularly valuable in that it treats upon a prehistoric context, and is thus unaided by the rich contextual information provided by historical sources; and it moves the debate away from the mortuary context towards other areas of lived experience – here the processes of constructing, inhabiting, engaging with and ultimately destroying an architecturally defined space. These are more ambitious and less obvious contexts for constructing emotional pasts. Where the authors are most successful is in the identification of cultural loci where emotions are developed and are involved in the construction of experience – such as in the production and reproduction of ‘sense of community’. Less convincing, for me, were the places where they follow the (mainly British prehistoric) ‘phenomenological’ tradition. My own view is that shared and expressed emotional values are more amenable to archaeological identification and analysis than personal emotional experience, and I shall try to explain why. I think by separating the social meanings of emotion from the physical experience of emotion the authors of this article might be able to pursue more fruitful kinds of enquiry.
EGSnrc computer modelling of megavoltage x-rays transmission through some shielding materials used in radiotherapy
Authors: Al-Ghorabie Fayez H.H. , Al-Lyhiani Saud S.H. , Natto Sameer S.A.
Published: November 2010

A computer user-code (TRANSMIT), based on the use of the EGSnrc Monte Carlo system, was developed to simulate the transmission of megavoltage x-rays through three different materials used for shielding purposes in radiotherapy. These materials are Lipowitz’s metal, lead and Rad-block. The simulations were performed for 4, 6 and 10 MV x-rays using narrow beam geometry in air. The linear attenuation coefficients, in cm–1, obtained from the simulated transmission curves for Lipowitz’s metal were 0.494, 0.470 and 0.452 for 4, 6 and 10 MV, respectively. For lead, the linear attenuation coefficients were 0.532, 0.507 and 0.483 for 4, 6 and 10 MV, respectively. For Rad-block, the linear attenuation coefficients were 0.561, 0.537 and 0.518 for 4, 6 and 10 MV, respectively. Comparison of the simulation results with experimental results reported in the literature gave a percent deviation <5% which indicates the validity of the simulation results. In addition, broad beam geometry calculations were performed for a variety of field sizes (10 × 10 cm2, 20 × 20 cm2and 40 × 40 cm2) using the three different attenuators. The results showed that broad beam attenuation coefficients decreased with increased field size and photon energy. For Lipowitz’s metal, the difference in the linear attenuation coefficient data between the broad beam attenuation coefficient and the narrow beam value lies between 3.6% and 20% depending on x-ray energy and field size. Similarly, the difference between the broad beam attenuation coefficient and the narrow beam value for lead lies between 1.5% and 10.4%. For the Rad-block material, the difference lies between 0.53% and 6.8%.
Spongeliomorpha in nonmarine settings: an ichnotaxonomic approach
Authors: Melchor Ricardo N. , Bromley Richard G. , Bedatou Emilio
Published: November 2010

The authors revise the occurrences of burrow networks with striated walls having dominantly transverse to oblique striae, which have been assigned to the ichnogeneraSpongeliomorphaSaporta, 1887, andSteinichnusBromley & Asgaard, 1979. The taxonomic status of the ichnogenusSteinichnusBromley & Asgaard, 1979 is examined and it is suggested that this ichnogenus is a subjective junior synonym ofSpongeliomorphaSaporta, 1887.Spongeliomorphais best reserved for an unlined network of burrows having distinct surface ridges or grooves of different orientation and massive filling. The diagnosis ofSpongeliomorphais emended accordingly and the proposed ichnospecies revised for consistency with the diagnostic features of the ichnogenus.Spongeliomorpha milfordensisMetz, 1993a is considered a subjective junior synonym ofSpongeliomorpha carlsbergi(Bromley & Asgaard, 1979) after a visual comparison and statistical analysis of the angle of striation with respect to the burrow midline in the type material. Nevertheless, the use of statistical techniques is not advocated for distinction of ichnotaxa, but may support observations.Spongeliomorpha carlsbergiis considered as an indicator of nonmarine settings and was probably produced by burrowing insects. Proposed ichnospecies ofSpongeliomorphathat fit the emended diagnosis includeS. sudolica(Zaręczny, 1878);S. ibericaSaporta, 1887;S. siculaD’Alessandro & Bromley, 1995;S. chevronensisMuñiz & Mayoral, 2001; andSpongeliomorphaisp. nov. aff.siculaLewy & Goldring, 2006.
Spore assemblages from the Lower Devonian ‘Lower Old Red Sandstone’ deposits of Arran, Scotland
Authors: Wellman Charles H.
Published: November 2010

Dispersed spore assemblages have been recovered from the Am Binnein Sandstones from the upper part of the ‘Lower Old Red Sandstone’ sequence on the island of Arran, Scotland. The spore assemblages belong with theEmphanisporites annulatus–Camarozonotriletes sextantii(AS) Spore Assemblage Biozone (SAB), indicating an Early Devonian, Emsian (but not earliest Emsian or latest Emsian) age. This is the first reliable age constraint for the ‘Lower Old Red Sandstone’ of Arran, and enables correlation with the more extensive sequence developed on the mainland in the Midland Valley of Scotland. The Am Binnein Sandstones are confirmed as correlatives of the Strathmore Group.
Front-end design of National Synchrotron Light Source II
Authors: Doom L. , Gash B. , Hussain M. , Job P. , Kosciuk B. , Ravindranath V. , Sharma S.
Published: November 2010

National Synchrotron Light Source II (NSLS-II) will be a 3-GeV, 792-m circumference third-generation synchrotron radiation facility with ultralow emittance and extremely high brightness. Front ends are required to transmit synchrotron radiation from the storage ring to the beam line while providing equipment and personnel protection. There will be up to 57 front ends in the NSLS-II facility with six in the baseline. Original designs are being developed and will be manufactured for three non-canted in-vacuum undulators, one canted in-vacuum undulator, one elliptically polarized undulator and one damping wiggler. Bending magnet and three-pole wiggler front ends are also being designed. Power densities range from 0.3 to 89.8 kW mrad−2, with total powers ranging from 0.34 to 64.5 kW. All components intercepting synchrotron radiation are water cooled and were analysed to confirm acceptable thermal limits.
Development of an eccentric cam-based active pre-alignment system for the compact linear collider main beam quadrupole magnet
Authors: Lackner F. , Artoos K. , Collette C. , Durand H. M. , Hauviller C. , Kemppinen J. , Leuxe R.
Published: November 2010

Compact linear collider (CLIC) is a study for a future electron–positron collider that would allow physicists to explore a new energy region beyond the capabilities of today's particle accelerators. The demanding transverse and vertical beam sizes and emittance specifications are resulting in stringent alignment and a nanometre stability requirement. In the current feasibility study, the main beam quadrupole magnets have to be actively pre-aligned with a precision of 1 µm in five degrees of freedom before being mechanically stabilized to the nanometre scale above 1 Hz. This contribution describes the approach of performing this active pre-alignment based on an eccentric cam system. In order to limit the amplification of the vibration sources at resonant frequencies, a sufficiently high eigenfrequency is required. Therefore, the contact region between cam and support was optimized for adequate stiffness based on the Hertzian theory. Furthermore, practical tests performed on a single-degree-of-freedom mockup will show the limitation factors and further improvements required for successful integration in a full-scale quadrupole mockup presently under design.
Crystallinity estimation of area-selective Ge epitaxial layer grown on Si substrate by means of high-resolution X-ray microdiffraction
Authors: Tsusaka Y. , Takano H. , Kagoshima Y. , Matsui J. , Park S. , Ishikawa Y. , Wada K.
Published: November 2010

Crystallinity of area-selective Ge layer with a (0 0 1) surface grown on Si substrate has been investigated by means of diffractometry using a parallel X-ray microbeam. The measured lattice parameters of 〈0 0 1〉 direction were about 0.17% smaller than that of bulk Ge crystal. This tensile strain value was almost the same as the simulated ones that used the finite-element method.
B18: What can the new core X-ray absorption spectroscopy beamline at Diamond do?
Authors: Ramos S. , Cibin G. , Parry S. , Scott S. M. , Varandas L. , Pearson M. R. , Gerring M. , Woolliscroft R. , Hudson L. , Robbins P. E. , Marsh A. , Hawkins D. , Deshmukh R. , Alexander S. , Dent A. J. , Krumpa N. A. , Smith A. D.
Published: November 2010

The new Core-XAS (X-ray absorption spectroscopy) beamline (B18) at Diamond aims to provide a reliable spectrometer for a broad scientific community. With this in mind, B18 has been built as a general-purpose beamline and offers to users a variety of sample environments and detection methods. Here we will present the first commissioning results and some of the capabilities of this versatile instrument.
Internetbasierte Therapie der sozialen Phobie: Ergebnisse einer 6-Monate-Katamnese
Authors: Berger Thomas , Hohl Eleonore , Caspar Franz
Published: November 2010

Zusammenfassung. Theoretischer Hintergrund: Internetbasierte psychotherapeutische Interventionen haben sich bei verschiedenen Angststörungen, insbesondere der sozialen Phobie, als wirksam erwiesen. Fragestellung: Ziel dieser Untersuchung ist die Überprüfung der mittelfristigen Wirksamkeit eines internetbasierten verhaltenstherapeutischen Programms in einer 6-Monate-Katamnese. Methode: 52 Patienten mit der primären Diagnose Soziale Phobie, die in einer kontrolliert randomisierten Studie das 10-wöchige Programm absolviert hatten ( Berger, Hohl & Caspar, 2009 ), wurden 6 Monate nach Abschluss der Intervention kontaktiert. 71.2% (37/52) beantworteten die Selbsteinschätzungsfragen der Follow-up-Messbatterie. Ergebnisse: Die signifikanten Prä-Post-Verbesserungen wurden nach 6 Monaten auf allen primären und sekundären Ergebnismaßen aufrechterhalten (Intention-to-Treat-Stichprobe). Auf den primären Sozialphobiemaßen wurden hohe Prä-Follow-up-Effektstärken gefunden (Cohen’s d = 1.19–1.37; Completer-Stichprobe). Schlussfolgerung: Die Behandlungseffektivität des internetbasierten Programms kann als mittelfristig stabil bewertet werden.
Erfassung psychotherapeutischer Kompetenzen
Authors: Weck Florian , Hautzinger Martin , Heidenreich Thomas , Stangier Ulrich
Published: November 2010

Zusammenfassung. Theoretischer Hintergrund: Die Cognitive Therapy Scale (CTS) ist ein international etabliertes Verfahren zur Erfassung psychotherapeutischer Kompetenzen. Fragestellung: Ziel der Studie war es, neuere Entwicklungen der CTS in eine deutschsprachige Version zu integrieren und deren psychometrische Eigenschaften zu überprüfen. Methode: Grundlage für die Validierung der CTS bildeten 30 videografierte Therapiesitzungen einer Therapiestudie zur Behandlung rezidivierender Depressionen. Die Therapeuten wurden hinsichtlich ihrer Kompetenz bei der Durchführung der Behandlungen von zwei Beurteilern eingeschätzt. Ergebnisse: Faktorenanalytisch ließen sich zwei Subskalen (sitzungsstrukturierende Kompetenzen, allgemeine therapeutische Kompetenzen) und ein Faktor höherer Ordnung (Gesamtwert) extrahieren. Insgesamt zeigte sich für die Skalen sowie für die meisten Einzelitems eine gute bis exzellente Beurteilerübereinstimmung. Schlussfolgerung: Die 14 Items umfassende deutschsprachige Version der CTS stellt ein vielversprechendes Instrument zur Beurteilung therapeutischer Kompetenzen dar.
Erfassung dysfunktionaler Kognitionen zum Body Checking
Authors: Neubauer Karolin , Bender Caroline , Tuschen-Caffier Brunna , Svaldi Jennifer , Blechert Jens
Published: November 2010

Zusammenfassung. Theoretischer Hintergrund: Empirische Befunde zeigen, dass körperbezogenes Kontrollverhalten und die zugrunde liegenden Kognitionen eine zentrale Rolle in der Aufrechterhaltung von Essstörungspsychopathologie spielen. Fragestellung: Eine deutschsprachige Version der Body Checking Cognitions Scale (BCCS) soll teststatistisch überprüft werden. Methode: Frauen mit Anorexia Nervosa (n = 19), Bulimia Nervosa (n = 22) und Binge-Eating Störung (n = 28) sowie eine weibliche nicht-klinische Vergleichsgruppe (n = 195) füllten die BCCS sowie weitere Fragebögen zur Essstörungspsychopathologie aus. Ergebnisse: Das 4-Faktorenmodell der englischsprachigen Originalversion zeigte in Faktorenanalysen die beste Passung. Die deutschsprachige BCCS erwies sich als intern konsistent und zeigte eine zufriedenstellende konvergente und diskriminante Validität. Schlussfolgerungen: Die deutschsprachige BCCS ist ein reliabler und valider Selbstbeurteilungsfragebogen. Sie stellt ein vielversprechendes Instrument zum Einsatz in der Essstörungstherapie und -forschung dar.
Layered convection and the impacts of the perovskite‐postperovskite phase transition on mantle dynamics under isochemical conditions
Authors: Shahnas M. H. , Peltier W. R.
Published: November 2010

The issue of the style of the mantle convection process remains important to the understanding of Earth's deep interior and surface processes. While results from structural seismology may be interpreted to support the existence of a whole mantle convection regime, in several geographic regions high‐resolution reconstructions of Benioff zone body wave heterogeneity demonstrate that the downgoing slab appears to be “trapped” in the transition zone rather than continuing to penetrate unimpeded into the lower mantle. The presence of the recently discovered exothermic perovskite‐postperovskite (Pv‐pPv) phase transition that appears to define the top of the D″ layer adjacent to the core‐mantle boundary may be expected to exert considerable impact on the mixing process. On the basis of the use of the most recent mantle parameters derived on the basis of mineral physics and a viscosity model inferred from glacial isostatic adjustment and Earth rotation observables, we reinvestigate the impact of the Pv‐pPv transition on mantle mixing. Our analyses are based on a newly constructed axisymmetric control volume model, which is described in detail. Analyses with this model demonstrate that the action of the Pv‐pPv transitions slightly decreases the tendency to layered flow due to the endothermic transitions that occur at 660 km depth and enhances the absolute radial mass flux especially in the lower mantle. However, the results also demonstrate that the episodically layered style of mantle mixing persists in models in which the strength of the Pv‐pPv transition is significant.
Influence of storm surges and sea level on shallow tidal basin erosive processes
Authors: Mariotti G. , Fagherazzi S. , Wiberg P. L. , McGlathery K. J. , Carniello L. , Defina A.
Published: November 2010

The finite‐element model WWTM is applied to a system of lagoons at the Virginia Coast Reserve, USA. The model solves the shallow water equations to compute tidal fluxes, and is equipped with a wave propagation module to calculate wave height during local wind events. The model is validated using measured water elevations, wave heights, and periods at five locations within the lagoon system. Scenarios with different wind conditions, storm surges, and relative sea level are simulated. Results are analyzed in terms of bottom shear stresses on the tidal flats, a measure of sediment resuspension potential, and total wave energy impacting the marsh boundaries, which is the chief process driving lateral marsh erosion. Results indicate that wave energy at the marsh boundaries is more sensitive to wind direction than are bottom shear stresses. Wave energy on marsh boundaries and bottom shear stresses on the tidal flats increase with sea level elevation, with the former increasing almost ten times more than the latter. Both positive and negative feedbacks between wave energy at the boundaries and bottom shear stresses are predicted, depending on the fate of the sediments eroded from the salt marsh boundaries.
Atmospheric boundary layer adjustment to the synoptic cycle at the Brazil‐Malvinas Confluence, South Atlantic Ocean
Authors: Acevedo Otávio C. , Pezzi Luciano P. , Souza Ronald B. , Anabor Vagner , Degrazia Gervásio A.
Published: November 2010

This study analyzes and discusses atmospheric boundary layer vertical profiles of potential temperature, specific humidity, and wind speed at each of the sides of the Brazil‐Malvinas Confluence in the southwestern Atlantic Ocean. Such confluence is characterized by the meeting of water masses with very different characteristics: the southern waters of the Malvinas current can be several degrees colder and appreciably less salty than the northern Brazil current waters. At the same time, a synoptic cycle can be identified at the region, marked by the successive passages of frontal systems and extratropical cyclones. The different phases of the synoptic cycle lead to different thermal advections at the confluence, causing respective different patterns of atmospheric boundary layer adjustment to the surface heterogeneity induced by the confluence. In the present study, this adjustment along the synoptic cycle is analyzed using data from five experiments performed across the confluence from 2003 to 2008. In each of the campaigns a number of soundings were launched from a ship at both sides of the confluence. A climatological analysis with respect to the closest frontal passage is presented, and it suggests that the observations collected at each of the years analyzed are referent to a different day of the synoptic cycle. The average profiles at each side of the confluence are in agreement with previous modeling studies of warm and cold thermal advection patterns over an oceanic front. Furthermore, our study shows that peculiar transitional characteristics are also observed between the conditions of well‐established warm and cold advection. At many phases of the synoptic cycle a strongly stratified boundary layer occurs at one or both sides of the confluence. Some of the observed characteristics, such as a large moisture accumulation near the surface, suggest that existing sensible and latent heat fluxes parameterizations fail under very strong stratifications, and the consequences of this deficiency are analyzed.
A 450 year record of spring‐summer flood layers in annually laminated sediments from Lake Ammersee (southern Germany)
Authors: Czymzik Markus , Dulski Peter , Plessen Birgit , von Grafenstein Ulrich , Naumann Rudolf , Brauer Achim
Published: November 2010

A 450 year spring‐summer flood layer time series at seasonal resolution has been established from the varved sediment record of Lake Ammersee (southern Germany), applying a novel methodological approach. The main results are (1) the attainment of a precise chronology by microscopic varve counting, (2) the identification of detrital layers representing flood‐triggered fluxes of catchment material into the lake, and (3) the recognition of the seasonality of these flood layers from their microstratigraphic position within a varve. Tracing flood layers in a proximal and a distal core and correlating them by application of the precise chronology provided information on the depositional processes. Comparing the seasonal flood layer record with daily runoff data of the inflowing River Ammer for the period from 1926 to 1999 allowed the definition of an approximate threshold in flood magnitude above which the formation of flood layers becomes very likely. Moreover, it was possible for the first time to estimate the “completeness” of the flood layer time series and to recognize that mainly floods in spring and summer, representing the main flood seasons in this region, are well preserved in the sediment archive. Their frequency distribution over the entire 450 year time series is not stationary but reveals maxima for colder periods of the Little Ice Age when solar activity was reduced. The observed spring‐summer flood layer frequency further shows trends similar to those of the occurrence of flood‐prone weather regimes since A.D. 1881, probably suggesting a causal link between solar variability and changes in midlatitude atmospheric circulation patterns.
Recent shoaling of the nutricline and thermocline in the western tropical Pacific
Authors: Williams Branwen , Grottoli Andréa G.
Published: November 2010

Long records of subsurface ocean observations are key to constrain our understanding of the climate response of the tropical Pacific to increasing greenhouse gases. Due to the lack of continuous ocean observations, proxies become essential to estimate changes in the tropical thermocline related to changes in Walker circulation. Here, we present high resolution stable nitrogen (δ15N) and carbon (δ13C) isotope records from three proteinaceous corals spanning the top 105 m of the euphotic zone from an offshore Palauan reef in the western tropical Pacific. Dated with radiocarbon‐derived growth chronologies, these isotope records indicate a shoaling of the mean nutricline and thus the thermocline as well, and a likely increase in primary productivity in the western tropical Pacific since the mid‐to‐late 1970s. Thus, these are the first subsurface proxy data extending below 20 m to support a slowdown of the tropical Pacific Walker circulation during the 20th Century.
Quality of reanalysis data during stratospheric vortex weakening and intensification events
Authors: Martineau Patrick , Son Seok‐Woo
Published: November 2010

The quality of five reanalysis data (ERA, JRA‐25, NASA‐MERRA, NCEP/DOE and NCEP/NCAR) is evaluated for stratospheric vortex weakening (SVW) and intensification (SVI) events in the Northern Hemisphere winter. A case study is carried out for a record‐breaking SVW event in 2009 whose spatio‐temporal structure is well observed by the COSMIC GPS RO measurements. It is found that most reanalysis data captured this event reasonably well despite non‐negligible biases are observed at 10 hPa especially in the JRA‐25. Composite analysis further shows that the temporal structure of the SVW and SVI events, as measured by the Northern Annular Mode (NAM) index, is almost identical among the data sets. Remarkably good agreement is found not only in the onset but also in their downward propagation with time. These results indicate that reanalysis data are reliable for examining stratospheric extreme events and their impact on the troposphere in an intraseasonal time scale.
Oxygen flux in the solar wind: Ulysses observations
Authors: von Steiger Rudolf , Zurbuchen Thomas H. , McComas David J.
Published: November 2010

We use the complete set of Ulysses solar wind data to conduct a comprehensive determination of the oxygen flux in relation to the proton flux in the solar wind during a wide range of solar activity levels. The data cover the heliosphere between 1.3 and 5.4 AU and, due to the unique orbit of Ulysses, all of the heliographic latitudes within ±80°. We find log‐normal distributions for O and H daily flux values, but with significant differences between slow and fast wind. Coronal hole‐associated fast wind has a distribution that is approximately three times narrower than the one of slow wind associated with streamers. Finally, we derive the solar oxygen abundance, finding a value of 8.82 ± 0.08, and discuss this value in comparison with the results of spectroscopic determinations.
Induction of antigen‐specific effector‐phase tolerance following vaccination against a previously ignored B‐cell lymphoma
Authors: Prato Sandro , Mintern Justine D , Lahoud Mireille H , Huang David C , Villadangos Jose A
Published: November 2010

The mechanisms of immune evasion during haematological malignancies are poorly understood. As lymphomas grow in lymphoid organs, it would be expected that if these lymphomas express neo‐antigens they should be readily detected by the immune system. To test this assumption, we generated a new non‐Hodgkin B‐cell lymphoma model expressing the model tumour neo‐antigen Ovalbumin (OVA), and analysed the endogenous antigen‐specific CD8+ T‐cell response that it elicited in recipient mice. The OVA+ lymphoma cells were eliminated by cytotoxic T lymphocytes (CTL) in mice that had been previously vaccinated against OVA. In contrast, the immune system of naïve mice ignored the malignant cells even though these continuously expressed and presented OVA on their MHC class I molecules. This state of ignorance could be overcome by therapeutic vaccination, which led to the expansion of endogenous anti‐OVA‐specific CD8+ T cells. However, the cytotoxic and interferon‐γ secretion capacity of these T cells were impaired. The tumour model that we describe thus reproduces several key aspects of human lymphoma; tumor ignorance can be broken by vaccination but the ensuing immune response remains ineffective. This model can be exploited to further understand the mechanisms of lymphoma immunoevasion and devise effective immunotherapy.
The role of Aire in clonal selection
Authors: Taniguchi Ruth T , Anderson Mark S
Published: November 2010

In his clonal selection theory, Frank Macfarlane Burnet predicted that autoreactive lymphocytes are deleted to prevent autoimmunity. This and other principles of lymphocyte behavior outlined by Burnet guided many studies that lead to our current understanding of thymic selection. Thus, when the genetic mutation responsible for autoimmune polyglandular syndrome type 1 was mapped to the autoimmune regulator (AIRE) gene, and Aire was found to be highly expressed in thymic epithelium, studying the role of Aire in negative selection made sense in the context of modern models of thymic selection. We now know Aire is a transcription factor required for the expression of many tissue‐specific antigens (TSAs) in the thymus. In the absence of functional Aire, human patients and mice develop multi‐organ autoimmune disease because of a defect in thymic negative selection. In addition to its role in the thymus, recent work in our lab suggests that extrathymic Aire‐expressing cells have an important role in the clonal deletion of autoreactive CD8+ T cells. In this review, we summarize the latest studies on thymic and peripheral Aire‐expressing cells, as well as other TSA‐expressing stromal cell populations in peripheral lymphoid organs. We also discuss theoretical differences in thymic and peripheral Aire function that warrant further studies.
Genetic interactions reveal the evolutionary trajectories of duplicate genes
Authors: VanderSluis Benjamin , Bellay Jeremy , Musso Gabriel , Costanzo Michael , Papp Balázs , Vizeacoumar Franco J , Baryshnikova Anastasia , Andrews Brenda , Boone Charles , Myers Chad L
Published: November 2010

The characterization of functional redundancy and divergence between duplicate genes is an important step in understanding the evolution of genetic systems. Large‐scale genetic network analysis in Saccharomyces cerevisiae provides a powerful perspective for addressing these questions through quantitative measurements of genetic interactions between pairs of duplicated genes, and more generally, through the study of genome‐wide genetic interaction profiles associated with duplicated genes. We show that duplicate genes exhibit fewer genetic interactions than other genes because they tend to buffer one another functionally, whereas observed interactions are non‐overlapping and reflect their divergent roles. We also show that duplicate gene pairs are highly imbalanced in their number of genetic interactions with other genes, a pattern that appears to result from asymmetric evolution, such that one duplicate evolves or degrades faster than the other and often becomes functionally or conditionally specialized. The differences in genetic interactions are predictive of differences in several other evolutionary and physiological properties of duplicate pairs.
Data Basin Climate Center: sharing and manipulating spatial information on the web
Authors: Bachelet Dominique , Strittholt James , Comendant Tosha
Published: November 2010

Monitoring datasets is essential to detect changes that are occurring and identify thresholds that cause them, but scientists around the world are now generating large volumes of data that vary in quality, format, supporting documentation, and accessibility. Moreover, diverse models are being run at various spatial and temporal scales to try and understand past climate variability and its impacts, generate future climate and land use scenarios, and project potential future impacts to the planet. Conservation practitioners and land managers are struggling to synthesize this wealth of information, identify relevant and usable datasets, and translate evolving science results into on-the-ground climate-aware strategies.In partnership with ESRI and Mambo media, the Conservation Biology Institute (CBI) is developing a versatile web-based resource that centralizes usable climate change-relevant datasets and provides analytical tools to visualize, analyze, and communicate findings for practical applications. To illustrate its capability to store, manipulate, and derive relevant conclusions to users, we present three examples of projects involving scientists and managers that are part of the Climate Center of Data Basin (http://www.databasin.org): a conservation project in the Puget Sound area of Washington State, a climate change impacts project in California, a North American project looking at climate change impacts on Canada lynx. We conclude by showing the use of this new web tool in workshops that bring together scientists and practitioners, allowing all to access the data and develop more effective management strategies.
Electrical characterization of zinc oxide/aluminum nitride thin film precursor field effect transistor structures: A conducting atomic force microscopy and density functional theoretical study
Authors: Dey Shirshendu , Jejurikar Suhas , Bhattacharya Somesh Kumar , Banerji Anirban , Adhi K. P. , Dharmadhikari C. V.
Published: November 2010

Electrical transport across pulsed laser deposited zinc oxide (ZnO)/aluminum nitride (AlN)/Si(100) thin film structures has been studied using conducting atomic force microscopy. Current versus voltage spectroscopy performed on the samples with varying AlN layer thickness (t), revealed asymmetric nonlinear behavior with a finite zero current region. The effective barrier height of the system is found to be (∼0.2 eV). The width of the zero current region was found to decrease exponentially with respect to t finally attaining the bulk band gap value. Density functional theory based calculations were carried out on the AlN and AlN–ZnO composite surface to investigate the band gap variation and ZnO adsorption on AlN. Results obtained by these calculations are in harmony with the experimental findings. Calculated values of the bulk cohesive energy explain the growth of the ZnO in an axis perpendicular to the surface supporting the experimentally observed results. Constant voltage current scans studies on the same sample showed the existence of current leakage spots. Current scans performed with varying bias voltages described an unambiguous growth profile of current leakage spots. These leakage spots were observed to evolve in a self similar pattern with the bias, which implied a possible existence of fractal dimension in the pattern of their growth. Mass fractal analysis is therefore carried out to model the growth pattern. Evolution of the mass-fractal with respect to the applied bias is found to be a case of Rayleigh distribution on a two-dimensional Poisson field, in the limiting case.
Oblique and cellular vortex shedding behind a circular cylinder in a bidirectional shear flow
Authors: Huang Zhiyong , Narasimhamurthy Vagesh D. , Andersson Helge I.
Published: November 2010

Vortex shedding in the transitional wake of a circular cylinder in a shear flow has been investigated. The focus has been on the effect of a bidirectional shear, i.e., the oncoming unidirectional flow varied linearly both in the spanwise and cross-stream directions. The computer experiments showed that the bidirectional shear resulted in a wake with oblique and cellular vortex shedding similar to the cylinder wake resulting from spanwise shear alone. The presence of a planar shear, however, gave rise to longer cellular cells. Due to the bidirectional shear inflow, the pressure was higher along the high-velocity side of the cylinder surface than along the low-velocity surface and at the same time exhibited a spanwise variation, which gave rise to secondary motions along the stagnation line and in the base region. Even though the cross-stream shear component was four times larger than the spanwise shear, the latter tended to dominate the three-dimensional wake dynamics.
Frequency and polarization dependence of thermal coupling between carbon nanotubes and SiO2
Authors: Ong Zhun-Yong , Pop Eric
Published: November 2010

We study heat dissipation from a (10,10) carbon nanotube (CNT) to a SiO2 substrate using equilibrium and nonequilibrium classical molecular dynamics. The CNT-substrate thermal boundary conductance is computed both from the relaxation time of the CNT-substrate temperature difference, and from the time autocorrelation function of the interfacial heat flux at equilibrium (Green–Kubo relation). The power spectrum of interfacial heat flux fluctuation and the time evolution of the internal CNT energy distribution suggest that: (1) thermal coupling is dominated by long wavelength phonons between 0–10 THz, (2) high frequency (40–57 THz) CNT phonon modes are strongly coupled to sub-40 THz CNT phonon modes, and (3) inelastic scattering between the CNT phonons and substrate phonons contributes to interfacial thermal transport. We also find that the low frequency longitudinal acoustic and twisting acoustic modes do not transfer energy to the substrate as efficiently as the low frequency transverse optical mode.
Characterizing mixed mode oscillations shaped by noise and bifurcation structure
Authors: Borowski Peter , Kuske Rachel , Li Yue-Xian , Cabrera Juan Luis
Published: November 2010

Many neuronal systems and models display a certain class of mixed mode oscillations (MMOs) consisting of periods of small amplitude oscillations interspersed with spikes. Various models with different underlying mechanisms have been proposed to generate this type of behavior. Stochastic versions of these models can produce similarly looking time series, often with noise-driven mechanisms different from those of the deterministic models. We present a suite of measures which, when applied to the time series, serves to distinguish models and classify routes to producing MMOs, such as noise-induced oscillations or delay bifurcation. By focusing on the subthreshold oscillations, we analyze the interspike interval density, trends in the amplitude, and a coherence measure. We develop these measures on a biophysical model for stellate cells and a phenomenological FitzHugh–Nagumo-type model and apply them on related models. The analysis highlights the influence of model parameters and resets and return mechanisms in the context of a novel approach using noise level to distinguish model types and MMO mechanisms. Ultimately, we indicate how the suite of measures can be applied to experimental time series to reveal the underlying dynamical structure, while exploiting either the intrinsic noise of the system or tunable extrinsic noise.
Monte Carlo cluster algorithm for fluid phase transitions in highly size-asymmetrical binary mixtures
Authors: Ashton Douglas J. , Liu Jiwen , Luijten Erik , Wilding Nigel B.
Published: November 2010

Highly size-asymmetrical fluid mixtures arise in a variety of physical contexts, notably in suspensions of colloidal particles to which much smaller particles have been added in the form of polymers or nanoparticles. Conventional schemes for simulating models of such systems are hamstrung by the difficulty of relaxing the large species in the presence of the small one. Here we describe how the rejection-free geometrical cluster algorithm of Liu and Luijten [J. Liu and E. Luijten, Phys. Rev. Lett. 92, 035504 (2004)] can be embedded within a restricted Gibbs ensemble to facilitate efficient and accurate studies of fluid phase behavior of highly size-asymmetrical mixtures. After providing a detailed description of the algorithm, we summarize the bespoke analysis techniques of [Ashton et al., J. Chem. Phys. 132, 074111 (2010)] that permit accurate estimates of coexisting densities and critical-point parameters. We apply our methods to study the liquid-vapor phase diagram of a particular mixture of Lennard-Jones particles having a 10:1 size ratio. As the reservoir volume fraction of small particles is increased in the range of 0%–5%, the critical temperature decreases by approximately 50%, while the critical density drops by some 30%. These trends imply that in our system, adding small particles decreases the net attraction between large particles, a situation that contrasts with hard-sphere mixtures where an attractive depletion force occurs.
High contrast optical detection of single graphenes on optically transparent substrates
Authors: Dorn M. , Lange P. , Chekushin A. , Severin N. , Rabe J. P.
Published: November 2010

The use of graphenes relies largely on their optical detection with Fabry–Pérot type structures. We demonstrate here that optical reflection mode imaging with single graphenes on the bottom of a bare transparent substrate such as mica can provide a high contrast of more than 12% for visible light. This can be explained with the destructive interference of light reflected from the substrate-graphene and graphene-air interfaces, similarly to black soap films. Since the contrast is only weakly wavelength dependent, white light contrast of single graphenes is sufficiently high to be easily detected with a human eye. We argue that with the graphene on the bottom of the transparent substrate high contrasts for single graphenes can also be achieved on other transparent substrates exhibiting a broad range of refractive indices.
Dependence of the number of hydrogen bonds per water molecule on its distance to a hydrophobic surface and a thereupon-based model for hydrophobic attraction
Authors: Djikaev Y. S. , Ruckenstein Eli
Published: November 2010

A water molecule in the vicinity of a hydrophobic surface forms fewer hydrogen bonds than a bulk molecule because the surface restricts the space available for other water molecules necessary for its hydrogen-bonding. In this vicinity, the number of hydrogen bonds per water molecule depends on its distance to the surface. Considering the number of hydrogen bonds per bulk water molecule (available experimentally) as the only reference quantity, we propose an improved probabilistic approach to water hydrogen-bonding that allows one to obtain an analytic expression for this dependence. (The original version of this approach [Y. S. Djikaev and E. Ruckenstein, J. Chem. Phys. 130, 124713 (2009)] provides the number of hydrogen bonds per water molecule in the vicinity of a hydrophobic surface as an average over all possible locations and orientations of the molecule.) This function (the number of hydrogen bonds per water molecule versus its distance to a hydrophobic surface) can be used to develop analytic models for the effect of hydrogen-bonding on the hydration of hydrophobic particles and their solvent-mediated interaction. Presenting a model for the latter, we also examine the temperature effect on the solvent-mediated interaction of two parallel hydrophobic plates.
Three-dimensional structure of electron density fluctuations in the Hall thruster plasma: E¯×B¯ mode
Authors: Tsikata S. , Honoré C. , Lemoine N. , Grésillon D. M.
Published: November 2010

Collective scattering measurements have been conducted on the plasma of a Hall thruster, in which the electron density fluctuations are fully characterized by the dynamic form factor. The dynamic form factor amplitude distribution has been measured depending on the k-vector spatial and frequency components at different locations. Fluctuations are seen as propagating waves. The largest amplitude mode propagates nearly along the cross-field direction but at a phase velocity that is much smaller than the E¯×B¯ drift velocity. Refined directional analysis of this largest amplitude mode shows a thin angular emission diagram with a mean direction that is not strictly along the E¯×B¯ direction but at small angles near it. The deviation is oriented toward the anode in the (E¯,E¯×B¯) plane and toward the exterior of the thruster channel in the (B¯,E¯×B¯) plane. The density fluctuation rate is on the order of 1%. These experimentally determined directional fluctuation characteristics are discussed with regard to the linear kinetic theory model and particle-in-cell simulation results.
The shock response of a rendered porcine fat
Authors: Wilgeroth J. M. , Hazell P. J. , Appleby-Thomas G. J.
Published: November 2010

Characterization of the shock response of biological materials is required in order to develop an understanding of how such materials behave under high strain-rate loading. In this work, a predominately linear Us-up Hugoniot relationship for a rendered porcine fat has been established using the plate-impact technique. This has been shown to take the form Us=1.58+2.47up (ρ0=0.945 g/cc) and comparison has been made between the dynamic behavior of the adipose material and both 20 wt % ballistic gelatin and water. The adipose material has been shown to behave in likeness with simple polymers such as polyethylene and to strengthen under shock loading, unlike ballistic gelatin, which has been shown to behave hydrodynamically. An experimental design incorporating direct insertion of lateral stress gauges within the rendered fat has given insight into both the behavior of lateral gauges and the lateral stress response of the material under dynamic loading.
Thermoelectric properties of YbxEu1−xCd2Sb2
Authors: Zhang H. , Fang L. , Tang M.-B. , Man Z. Y. , Chen H. H. , Yang X. X. , Baitinger M. , Grin Y. , Zhao J.-T.
Published: November 2010

The thermoelectric performance of EuCd2Sb2 and YbCd2Sb2 was improved by mixed cation occupation. The composition, structure, and thermoelectric properties of YbxEu1−xCd2Sb2 (x=0, 0.5, 0.75, and 1) have been investigated. Polycrystalline samples are prepared by direct reaction of the elements. Thermoelectric properties were investigated after densification of the materials by spark plasma sintering. YbxEu1−xCd2Sb2 crystallizes in the P3¯m1 space group. The lattice parameters increase with the europium content. These materials show low electrical resistivity, high Seebeck coefficient, and low thermal conductivity together with high carrier concentration and high carrier mobility. ZT values of 0.88 and 0.97 are obtained for Yb0.5Eu0.5Cd2Sb2 and Yb0.75Eu0.25Cd2Sb2 at 650 K, respectively.
The ultraviolet photodissociation of axial and equatorial conformers of 3-pyrroline
Authors: Oliver Thomas A. A. , King Graeme A. , Ashfold Michael N. R.
Published: November 2010

Resolved sets of photoproducts arising from the photodissociation of axial and equatorial conformers of 3-pyrroline have been observed using H(Rydberg) atom photofragment translational spectroscopy following excitation in the wavelength range of 250–213 nm. 3-pyrroline (alternatively 2,5-dihydropyrrole) is a five membered partially saturated heterocycle in which the bonding around the N atom is pyramidal (sp3 hybridized) and the N–H bond can lie either axial or equatorial to the ring. Careful analysis of total kinetic energy release data derived from H atom time-of-flight measurements reveals excitation of the 3-pyrrolinyl cofragment consistent with N–H bond fission in both the axial and equatorial conformers. This allows determination of the energy difference between the ground state conformers to be 340±50 cm−1 and the N–H bond strength for axial and equatorial conformers as 31 610±50 and 31 270±50 cm−1, respectively.