Perturbative Gravity and Twistor Space

The recent progress in computing gauge theory amplitudes can be extended, in many cases, to theories incorporating gravity. This has improved our understanding of the perturbative expansion of N=8 supergravity supporting the ``no-triangle hypothesis'' that N=8 one-loop amplitudes may be expressed in terms of scalar box integral functions.Comment: Talk presented by N. E. J. Bjerrum-Bohr at Loop and Legs 2006, 5 page

Similarities of gauge and gravity amplitudes

We review recent progress in computations of amplitudes in gauge theory and gravity. We compare the perturbative expansion of amplitudes in N=4 super Yang-Mills and N=8 supergravity and discuss surprising similarities.Comment: Talk presented by Harald Ita at "Continuous Advances in QCD 2006", 7 page

Cattle develop neutralizing antibodies to rotavirus serotypes which could not be isolated from faeces of symptomatic calves

Neutralizing antibodies against 10 serotypes of rotavirus were measured in sera from different age groups of German cattle. Only five of 143 sera did not neutralize heterologous serotypes. Sera from 64 of 76 calves younger than 1 year neutralized bovine rotavirus NCDV (serotype 6). From these calves, sera 54, 26, 51, 24, 12, 10 and 37, in neutralized addition, the heterologous serotypes 1, 2, 3, 4, 5, 7 and 9, respectively. Thirty-eight of 46 rotavirus isolates from Bavarian calves with diarrhoea were serotyped by neutralization: 22, 2 and 14 isolates were typed as serotype 6, serotype 10 (B223) and a newly defined subtype of serotype 10 (V1005), respectively. All serotype 6 isolates and none of the serotype 10 or V1005-like viruses tested hybridized to a NCDV-specific cDNA probe. Eight isolates gave equivocal results by neutralization. We failed however to identify serotype 1, 2, 3, 4 or 8 bovine rotavirus isolates by neutralization with hyperimmune sera and dot blot hybridization with serotype-specific cDNA probes. Thus cross-reacting antibodies in cattle might not represent an anamnestic response, but the recognition of a cross-reacting neutralization epitope shared by many rotavirus serotype

Antigenic and biochemical characterization of bovine rotavirus V1005, a new member of rotavirus serotype 10

Bovine rotavirus (BRV) V1005 is serologically distinct from rotavirus serotypes 1, 2, 3, 4, 5, 6, 8 and 9. BRV V1005 showed cross-reactions with BRV B223, the American prototype of serotype 10 rotavirus, and with BRV E4049, a British serotype 10 isolate. BRV V1005 was, however, not neutralized by four monoclonal antibodies directed against VP7 of BRV B223. Two-way cross-reactions were observed between BRV V1005 and a reassortant rotavirus containing the VP4 from BRV UK. In addition the major tryptic cleavage product of VP4, VP5*, from BRV V1005 is indistinguishable by peptide mapping and its isoelectric point from the homologous protein of BRV UK, but is clearly different from VP5* of BRV NCDV. The peptide map of VP7 from BRV V1005 differed from that obtained for VP7 of BRV U

Degradation of small simple and large complex lunar craters: Not a simple scale dependence

The crater record of a planetary surface unit is often analyzed by its cumulative size‐frequency distribution (CSFD). Measuring CSFDs involves traditional approaches, such as traditional crater counting (TCC) and buffered crater counting (BCC), as well as geometric corrections, such as nonsparseness correction (NSC) and buffered nonsparseness correction (BNSC). NSC and BNSC consider the effects of geometric crater obliteration on the CSFD. On the Moon, crater obliteration leads to two distinct states in which obtained CSFDs do not match the production CSFD—crater equilibrium and nonsparseness. Crater equilibrium occurs when each new impact erases a preexisting crater of the same size. It is clearly observed on lunar terrains dominated by small simple craters with steep‐sloped production CSFDs, such as Imbrian to Eratosthenian‐era mare units. Nonsparseness, on the other hand, is caused by the geometric overlap of preexisting craters by a new impact, which is also known as “cookie cutting.” Cookie cutting is most clearly observed on lunar terrains dominated by large craters with shallow‐sloped production CSFDs, such as the pre‐Nectarian lunar highlands. We use the Cratered Terrain Evolution Model (CTEM) to simulate the evolution of a pre‐Nectarian surface unit. The model was previously used to simulate the diffusion‐induced equilibrium for small craters of the lunar maria. We find that relative to their size, large craters contribute less to the diffusion of the surrounding landscape than small craters. Thus, a simple scale dependence cannot account for the per‐crater contribution to degradation by small simple and large complex craters

Critical practice of grant application and administration: an intervention

Introduction: Researchers experience increasing pressures to connect with bodies that finance their projects. In this climate, critical scholars face many obstacles as they seek to navigate the treacherous waters of securing external funds. To debate these challenges, the ACME Editorial Collective organized a panel for the 2009 Annual Meeting of the Association of American Geographers in Las Vegas. This intervention represents a follow-up discussion and collective writing process among some of the panelists and members of the audience who attended the panel. Below, we examine the neoliberalization of the current funding systems, discuss the implications for research practice, and make suggestions for critical engagement and transformation. Our suggestions, however, will not be easy to implement, as we can infer from the experience of the radical scholars of the post-1968 generation whose ascension into the upper echelons of North American and European university systems was also associated with the neoliberalization of the funding systems. This intervention represents a modest contribution in the tradition of critical research practice of creating the possibilities for progressive change

Comment on "A centroid molecular dynamics study of liquid para hydrogen and ortho deuterium" [J. Chem. Phys. 121, 6412 (2004)]

We show that the two phase points considered in the recent simulations of liquid para hydrogen by Hone and Voth lie in the liquid-vapor coexistence region of a purely classical molecular dynamics simulation. By contrast, their phase point for ortho deuterium was in the one-phase liquid region for both classical and quantum simulations. These observations are used to account for their report that quantum mechanical effects enhance the diffusion in liquid para hydrogen and decrease it in ortho deuterium

On the structural changes in the Brewer-Dobson circulation after 2000

In this paper we present evidence that the observed increase in tropical upwelling after the year 2000 may be attributed to a change in the Brewer-Dobson circulation pattern. For this purpose, we use the concept of transit times derived from residual circulation trajectories and different in-situ measurements of ozone and nitrous dioxide. Observations from the Canadian midlatitude ozone profile record, probability density functions of in-situ N2O observations and a shift of the N2O-O3 correlation slopes, taken together, indicate that the increased upwelling in the tropics after the year 2000 appears to have triggered an intensification of tracer transport from the tropics into the extratropics in the lower stratosphere below about 500 K. This finding is corroborated by the fact that transit times along the shallow branch of the residual circulation into the LMS have decreased for the same time period (1993–2003). On a longer time scale (1979–2009), the transit time of the shallow residual circulation branch show a steady decrease of about −1 month/decade over the last 30 years, while the transit times of the deep branch remain unchanged. This highlights the fact that a change in the upwelling across the tropical tropopause is not a direct indicator for changes of the whole Brewer-Dobson circulation

White matter differences between healthy young ApoE4 carriers and non-carriers identified with tractography and support vector machines.

The apolipoprotein E4 (ApoE4) is an established risk factor for Alzheimer's disease (AD). Previous work has shown that this allele is associated with functional (fMRI) changes as well structural grey matter (GM) changes in healthy young, middle-aged and older subjects. Here, we assess the diffusion characteristics and the white matter (WM) tracts of healthy young (20-38 years) ApoE4 carriers and non-carriers. No significant differences in diffusion indices were found between young carriers (ApoE4+) and non-carriers (ApoE4-). There were also no significant differences between the groups in terms of normalised GM or WM volume. A feature selection algorithm (ReliefF) was used to select the most salient voxels from the diffusion data for subsequent classification with support vector machines (SVMs). SVMs were capable of classifying ApoE4 carrier and non-carrier groups with an extremely high level of accuracy. The top 500 voxels selected by ReliefF were then used as seeds for tractography which identified a WM network that included regions of the parietal lobe, the cingulum bundle and the dorsolateral frontal lobe. There was a non-significant decrease in volume of this WM network in the ApoE4 carrier group. Our results indicate that there are subtle WM differences between healthy young ApoE4 carriers and non-carriers and that the WM network identified may be particularly vulnerable to further degeneration in ApoE4 carriers as they enter middle and old age