| 41. |
- Abate, E., et al.
(författare)
-
Combined performance tests before installation of the ATLAS Semiconductor and Transition Radiation Tracking Detectors
- 2008
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- The ATLAS (A Toroidal LHC ApparatuS) Inner Detector provides charged particle tracking in the centre of the ATLAS experiment at the Large Hadron Collider (LHC). The Inner Detector consists of three subdetectors: the Pixel Detector, the Semiconductor Tracker (SCT), and the Transition Radiation Tracker (TRT). This paper summarizes the tests that were carried out at the final stage of SCT+TRT integration prior to their installation in ATLAS. The combined operation and performance of the SCT and TRT barrel and endcap detectors was investigated through a series of noise tests, and by recording the tracks of cosmic rays. This was a crucial test of hardware and software of the combined tracker detector systems. The results of noise and cross-talk tests on the SCT and TRT in their final assembled configuration, using final readout and supply hardware and software, are reported. The reconstruction and analysis of the recorded cosmic tracks allowed testing of the offline analysis chain and verification of basic tracker performance parameters, such as efficiency and spatial resolution, in combined operation before installation.
|
|
| 42. |
- Abayneh, Sisay A, et al.
(författare)
-
Sensitivity of HIV-1 primary isolates to human anti-CD40 antibody-mediated suppression is related to co-receptor use
- 2008
-
Ingår i: AIDS Research and Human Retroviruses. - : Mary Ann Liebert Inc. - 1931-8405 .- 0889-2229. ; 24:3, s. 447-452
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of CD40 ligation on infection by HIV-1 primary isolates with different R5 phenotypes was evaluated with a novel set of anti-CD40 monoclonal antibodies originating from a human phage display library. Five human monoclonal anti-CD40 antibodies of IgG1 subtype characterized by the ability to activate B cells via CD40 were tested for induction of the CC-chemokines RANTES and MIP-1alpha and inhibition of HIV-1 replication in primary monocyte-derived macrophages (MDM). All activating anti-CD40 antibodies were able to induce CC-chemokines in MDM. We chose the most potent antibody, clone B44, for further experiments. This antibody had a suppressive effect on HIV-1 isolates of the R5 phenotype with limited use of CCR5/CXCR4 chimeric receptors. In comparison, HIV-1 isolates with broader use of CCR5/CXCR4 chimeric receptors or with CXCR4 use were less sensitive to anti-CD40-induced suppression. The results indicate that HIV-1 replication is inhibited by human anti-CD40 monoclonal antibodies through the mechanism of CC-chemokine induction. This effect is thus restricted to HIV-1 isolates sensitive to inhibition by CC-chemokines.
|
|
| 43. |
- Abbas, Mazhar, et al.
(författare)
-
Biosorption of chromium (III) and chromium (VI) by untreated and pretreated Cassia fistula biomass from aqueous solutions
- 2008
-
Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 1573-2932 .- 0049-6979. ; 191:1-4, s. 139-148
-
Tidskriftsartikel (refereegranskat)abstract
- The present study explained the effect of pretreatments on the biosorption of Cr (III) and Cr (VI) by Cassia fistula biomass from aqueous solutions. For this purpose Cassia fistula biomass was pretreated physically by heating, autoclaving, boiling and chemically with sodium hydroxide, formaldehyde, gluteraldehyde, acetic acid, hydrogen peroxide, commercial laundry detergent, orthophosphoric, sulphuric acid, nitric acid, and hydrochloric acid. The adsorption capacity of biomass for Cr (III) and Cr (VI) was found to be significantly improved by the treatments of gluteraldehyde (95.41 and 96.21 mg/g) and benzene (85.71 and 90.81 mg/g) respectively. The adsorption capacity was found to depend on pH, initial metal concentration, dose, size, kinetics, and temperature. Maximum adsorption of both the Cr (III) and Cr (VI) was observed at pH 5 and 2. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The kinetic studies showed that the sorption rates could be described better by a second order expression than by a more commonly applied Lagergren equation.
|
|
| 44. |
- Abbott, Jessica, et al.
(författare)
-
Correlated morphological and colour differences among females of the damselfly Ischnura elegans
- 2009
-
Ingår i: Ecological Entomology. - : Wiley. - 1365-2311 .- 0307-6946. ; 34:3, s. 378-386
-
Tidskriftsartikel (refereegranskat)abstract
- 1. The female-limited colour polymorphic damselfly Ischnura elegans has proven to be an interesting study organism both as an example of female sexual polymorphism, and in the context of the evolution of colour polymorphism, as a model of speciation processes. 2. Previous research suggests the existence of correlations between colour morph and other phenotypic traits, and the different female morphs in I. elegans may be pursuing alternative phenotypically integrated strategies. However, previous research on morphological differences in southern Swedish individuals of this species was only carried out on laboratory-raised offspring from a single population, leaving open the question of how widespread such differences are. 3. The present study therefore analysed multi-generational data from 12 populations, investigating morphological differences between the female morphs in the field, differences in the pattern of phenotypic integration between morphs, and quantified selection on morphological traits. 4. It was found that consistent morphological differences indeed existed between the morphs across populations, confirming that the previously observed differences were not simply a laboratory artefact. It was also found, somewhat surprisingly, that despite the existence of sexual dimorphism in body size and shape, patterns of phenotypic integration differed most between the morphs and not between the sexes. Finally, linear selection gradients showed that female morphology affected fecundity differently between the morphs. 5. We discuss the relevance of these results to the male mimicry hypothesis and to the existence of potential ecological differences between the morphs.
|
|
| 45. |
- Abbott, J. K., et al.
(författare)
-
Patterns of differentiation in a colour polymorphism and in neutral markers reveal rapid genetic changes in natural damselfly populations
- 2008
-
Ingår i: Molecular Ecology. - : Wiley-Blackwell. - 0962-1083 .- 1365-294X. ; 17:6, s. 1597-1604
-
Tidskriftsartikel (refereegranskat)abstract
- The existence and mode of selection operating on heritable adaptive traits can be inferred by comparing population differentiation in neutral genetic variation between populations (often using F-ST values) with the corresponding estimates for adaptive traits. Such comparisons indicate if selection acts in a diversifying way between populations, in which case differentiation in selected traits is expected to exceed differentiation in neutral markers [F-ST (selected) > F-ST (neutralfl, or if negative frequency-dependent selection maintains genetic polymorphisms and pulls populations towards a common stable equilibrium [FST (selected) < F-ST (neutral)]. Here, we compared F-ST values for putatively neutral data (obtained using amplified fragment length polymorphism) with estimates of differentiation in morph frequencies in the colour-polymorphic damselfly Ischnura elegans. We found that in the first year (2000), population differentiation in morph frequencies was significantly greater than differentiation in neutral loci, while in 2002 (only 2 years and 2 generations later), population differentiation in morph frequencies had decreased to a level significantly lower than differentiation in neutral loci. Genetic drift as an explanation for population differentiation in morph frequencies could thus be rejected in both years. These results indicate that the type and/or strength of selection on morph frequencies in this system can change substantially between years. We suggest that an approach to a common equilibrium morph frequency across all populations, driven by negative frequency-dependent selection, is the cause of these temporal changes. We conclude that inferences about selection obtained by comparing F-ST values from neutral and adaptive genetic variation are most useful when spatial and temporal data are available from several populations and time points and when such information is combined with other ecological sources of data.
|
|
| 46. |
- Abbott, Jessica, et al.
(författare)
-
Ontogeny of sexual dimorphism and phenotypic integration in heritable morphs
- 2008
-
Ingår i: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 1573-8477 .- 0269-7653. ; 22:1, s. 103-121
-
Tidskriftsartikel (refereegranskat)abstract
- In this study we investigated the developmental basis of adult phenotypes in a non-model organism, a polymorphic damselfly (Ischnura elegans) with three female colour morphs. This polymorphic species presents an ideal opportunity to study intraspecific variation in growth trajectories, morphological variation in size and shape during the course of ontogeny, and to relate these juvenile differences to the phenotypic differences of the discrete adult phenotypes; the two sexes and the three female morphs. We raised larvae of different families in individual enclosures in the laboratory, and traced morphological changes during the course of ontogeny. We used principal components analysis to examine the effects of Sex, Maternal morph, and Own morph on body size and body shape. We also investigated the larval fitness consequences of variation in size and shape by relating these factors to emergence success. Females grew faster than males and were larger as adults, and there was sexual dimorphism in body shape in both larval and adult stages. There were also significant effects of both maternal morph and own morph on growth rate and body shape in the larval stage. There were significant differences in body shape, but not body size, between the adult female morphs, indicating phenotypic integration between colour, melanin patterning, and body shape. Individuals that emerged successfully grew faster and had different body shape in the larval stage, indicating internal (non-ecological) selection on larval morphology. Overall, morphological differences between individuals at the larval stage carried over to the adult stage. Thus, selection in the larval stage can potentially result in correlated responses in adult phenotypes and vice versa.
|
|
| 47. |
- Abbott, Jessica, et al.
(författare)
-
Phenotypic and genetic variation in emergence and development time of a trimorphic damselfly
- 2005
-
Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 18:6, s. 1464-1470
-
Tidskriftsartikel (refereegranskat)abstract
- Although colour polymorphisms in adult organisms of many taxa are often adaptive in the context of sexual selection or predation, genetic correlations between colour and other phenotypic traits expressed early in ontogeny could also play an important role in polymorphic systems. We studied phenotypic and genetic variation in development time among female colour morphs in the polymorphic damselfly Ischnura elegans in the field and by raising larvae in a common laboratory environment. In the field, the three different female morphs emerged at different times. Among laboratory-raised families, we found evidence of a significant correlation between maternal morph and larval development time in both sexes. This suggests that the phenotypic correlation between morph and emergence time in the field has a parallel in a genetic correlation between maternal colour and offspring development time. Maternal colour morph frequencies could thus potentially change as correlated responses to selection on larval emergence dates. The similar genetic correlation in male offspring suggests that sex-limitation in this system is incomplete, which may lead to an ontogenetic sexual conflict between selection for early male emergence (protandry) and emergence times associated with maternal morph.
|
|
| 48. |
- Abbott, Karen C., et al.
(författare)
-
Environmental variation in ecological communities and inferences from single-species data
- 2009
-
Ingår i: Ecology. - 0012-9658. ; 90:5, s. 1268-1278
-
Tidskriftsartikel (refereegranskat)abstract
- Data are often collected for a single species within an ecological community, so quantitative tools for drawing inferences about the unobserved portions of the community from single-species data are valuable. In this paper, we present and examine a method for estimating community dimension (the number of strongly interacting species or groups) from time series data on a single species. The dynamics of one species can be strongly affected by environmental stochasticity acting not only on itself, but also on other species with which it interacts. By fully accounting for the effects of stochasticity on populations embedded in a community, our approach gives better estimates of community dimension than commonly used methods. Using a combination of time series data and simulations, we show that failing to properly account for stochasticity when attempting to relate population dynamics to attributes of the community can give misleading information about community dimension.
|
|
| 49. |
- Abd, Hadi, et al.
(författare)
-
Ante mortem diagnosis of amoebic encephalitis in a haematopoietic stem cell transplanted patient
- 2009
-
Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 41:8, s. 619-622
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Acanthamoeba species are widely distributed free-living amoebae showing an increased role as human pathogens causing encephalitis, keratitis, pneumonitis and dermatitis. A haematopoietic stem cell transplanted (HSCT) patient developed purulent meningitis while awaiting regrafting. The meningitis was thought to be an endogenous infection arising from the mucous membranes primarily involving the cervicofacial regions, probably due to haematogenous spread facilitated by surgery. We diagnosed a fatal case of granulomatous amoebic encephalitis caused by Acanthamoeba castellanii by direct microscopy of a cerebrospinal fluid sample (CSF), Acanthamoeba cultivation, Giemsa staining, polymerase chain reaction and sequencing.
|
|
| 50. |
- Abdallah, J., et al.
(författare)
-
A determination of the centre-of-mass energy at LEP2 using radiative two-fermion events
- 2006
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 46:2, s. 295-305
-
Tidskriftsartikel (refereegranskat)abstract
- Using e(+)e(-) -> mu(+)mu(-)(gamma) and e(+)e(-) -> q (q) over bar(gamma) events radiative to the Z pole, DELPHI has determined the centre-of-mass energy, root s, using energy and momentum constraint methods. The results are expressed as deviations from the nominal LEP centre-of-mass energy, measured using other techniques. The results are found to be compatible with the LEP Energy Working Group estimates for a combination of the 1997 to 2000 data sets.
|
|
