Gauging CSO groups in N=4 Supergravity

We investigate a class of CSO-gaugings of N=4 supergravity coupled to six vector multiplets. Using the CSO-gaugings we do not find a vacuum that is stable against all scalar perturbations at the point where the matter fields are turned off. However, at this point we do find a stable cosmological scaling solution.Comment: 21 page

In vitro 2-deoxy-2-[18F]fluoro-D-glucose uptake: practical considerations

In oncology 2-deoxy-2-[F-18]fluoro-D-glucose ([F-18]-FDG), a glucose analogue, is the most used positron emission tomography (PET) tracer. There are however some limitations due to low metabolic activity or high surrounding physiological uptake in several tumors or regions. Investigating new tracers or methods is expensive and elaborative when animal experiments or phase I clinical trials are used. In vitro experiments can overcome these limitations. We analyzed the influence of incubation time, cell medium conditions, administered activity, and cell density on [F-18]-FDG uptake in six different cell cultures. Glucose transporter 1 (GLUT1)- and hexokinase 2 (HK2)-expression at high and low cell density was analyzed using immunocytochemistry. FDG-uptake increases over time and absence of glucose in the incubation medium increases uptake. By increasing the administered activity, uptake per protein also increases and tracer uptake per protein is lower at higher cell densities. Immunocytochemical analysis reveals a lower expression of both GLUT1 and HK2 at higher cell concentrations. All investigated parameters influenced FDG uptake and therefore we can conclude it is of utmost importance to keep administered activity, incubation medium, and time constant and to correct uptake when cell density changes due to environmental conditions, such as therapy

Group Manifold Reduction of Dual N=1 d=10 Supergravity

We perform a group manifold reduction of the dual version of N=1 d=10 supergravity to four dimensions. The effects of the 3- and 4-form gauge fields in the resulting gauged N=4 d=4 supergravity are studied in particular. The example of the group manifold SU(2)xSU(2) is worked out in detail, and we compare for this case the four-dimensional scalar potential with gauged N=4 supergravity.Comment: 22 pages, revised section 3, typos corrected. Published versio

Quantitative pretreatment VOI analysis of liver metastases 99mTc-MAA SPECT/CT and FDG PET/CT in relation with treatment response to SIRT

Using quantitive VOI analysis, the percentage Tc-99m-MAA uptake and SUVmax and mean values of liver metastases obtained prior to SIRT were related to treatment response using both a lesion-based and clinical dichotomous approach. Based on the VOI % of Tc-99m-MAA activity, the estimated Y-90-microspheres activity/cc (MBq/cc) was calculated from the effective dose injected. Baseline VOI FDG PET SUVmean and max values and estimated MBq/cc values were related to treatment response using a lesion-based approach (% change in SUVmean >= 50%) and a clinical dichotomous approach. Fifteen treatment sessions were analyzed (13 patients). Using the lesion-based approach (12 treatment sessions) 40 lesions responded and 37 did not. SUVmax and mean values proved significantly different between non-responding and responding lesions; 18:6 (SD 10.8) versus 13.5 (SD 8.4) for SUVmax (p = 0.02) and 11.4 (SD 3.8) versus 6.3 (SD 4.5) for SUVmean (p = 0.002). Using the clinical dichotomous approach (15 treatment sessions / 11 responding), 91 lesions were analyzed; 57 responded. VOI volumes and estimated Y-90-loaded glass microspheres activity (MBq/cc) did not differ between responders and non responders; 24 cc (SD 27) versus 21 cc (SD 21 cc) (p = 0.4) and 1.95 MBq/cc (SD 1.1 MBq/cc) versus 1.90 MB/cc (SD 2.7 MBq/cc) (p = 0.92). On the contrary, SUVmax and mean values proved significantly different between responders and non-responders; 23.7 (SD 9.8) versus 9.4 (SD 3.8) for SUVmax (p = 0.0001) and 13.1 (SD 8.1) versus 4.9 (SD 1.4) for SUVmean. Conclusion: These findings suggest that in patients presenting with high baseline SUVmax and mean values, the administration of higher activities or alternatively, other potentially more useful treatment options might be considered

Diets of abundant fishes from beach seine catches in seagrass beds of a tropical bay (Gazi Bay, Kenya)

The composition of the diet of 14 fish species that were common in beach seine catches over the seagrass beds of Gazi Bay (Kenya) was investigated. Three trophic guilds could be distinguished based on dietary diversity and on the numerical and gravimetrical composition of the diet. Herklotsichthys quadrimaculatus, Stolephorus indicus and Atherinomorus duodecimalis were planktivores. Their stomach fullness index was low and the diet was not diverse. The main food items were harpacticoid and calanoid copepods and brachyuran zoea and megalopae. Apogon thermalis, Fowleria aurita, Paramonacanthus barnardi, Mulloides flavolineatus, Lutjanus fulviflamma, L. argentimaculatus and Gerres acinaces were benthivores, mainly feeding on small epi- and hyperbenthic prey. Their diet was very diverse and it was dominated by Amphipoda (Gammaridea), Tanaidacea and Mysidacea. Their fullness indices were low, but a little bit higher than those observed for the planktivores. A third group were the 'piscivores': Bothus myriaster, Fistularia commersonii, Sphyraena barracuda and Plotosus lineatus. The dominant items in the food spectrum of these species were postlarval fishes and large nektonic invertebrates (gammaridean amphipods, mysids, shrimp and crabs). Their diet was not diverse and the fullness index was much higher than that of the other species examined. All other species caught were further classified according to the following feeding guilds: herbivores, planktivores, benthivores (epi- and hyperbenthivores) and piscivores. The ichthyofauna of Gazi Bay was clearly dominated by benthivores

Selfduality of non-linear electrodynamics with derivative corrections

In this paper we investigate how electromagnetic duality survives derivative corrections to classical non-linear electrodynamics. In particular, we establish that electromagnetic selfduality is satisfied to all orders in $\alpha'$ for the four-point function sector of the four dimensional open string effective action.Comment: 8 page

De Sitter solutions in N=4 matter coupled supergravity

We investigate the scalar potential of gauged N=4 supergravity with matter. The extremum in the SU(1,1)/U(1) scalars is obtained for an arbitrary number of matter multiplets. The constraints on the matter scalars are solved in terms of an explicit parametrisation of an SO(6,6+n) element. For the case of six matter multiplets we discuss both compact and noncompact gauge groups. In an example involving noncompact groups and four scalars we find a potential with an absolute minimum and a positive cosmological constant.Comment: 14 page