| 1. |
|
|
| 2. |
- Lewis, Cathryn M, et al.
(författare)
-
Genome scan meta-analysis of schizophrenia and bipolar disorder, part II : Schizophrenia
- 2003
-
Ingår i: American Journal of Human Genetics. - 0002-9297 .- 1537-6605. ; 73:1, s. 34-48
-
Tidskriftsartikel (refereegranskat)abstract
- Schizophrenia is a common disorder with high heritability and a 10-fold increase in risk to siblings of probands. Replication has been inconsistent for reports of significant genetic linkage. To assess evidence for linkage across studies, rank-based genome scan meta-analysis (GSMA) was applied to data from 20 schizophrenia genome scans. Each marker for each scan was assigned to 1 of 120 30-cM bins, with the bins ranked by linkage scores (1 = most significant) and the ranks averaged across studies (R(avg)) and then weighted for sample size (N(sqrt)[affected casess]). A permutation test was used to compute the probability of observing, by chance, each bin's average rank (P(AvgRnk)) or of observing it for a bin with the same place (first, second, etc.) in the order of average ranks in each permutation (P(ord)). The GSMA produced significant genomewide evidence for linkage on chromosome 2q (PAvgRnk<.000417). Two aggregate criteria for linkage were also met (clusters of nominally significant P values that did not occur in 1,000 replicates of the entire data set with no linkage present): 12 consecutive bins with both P(AvgRnk) and P(ord)<.05, including regions of chromosomes 5q, 3p, 11q, 6p, 1q, 22q, 8p, 20q, and 14p, and 19 consecutive bins with P(ord)<.05, additionally including regions of chromosomes 16q, 18q, 10p, 15q, 6q, and 17q. There is greater consistency of linkage results across studies than has been previously recognized. The results suggest that some or all of these regions contain loci that increase susceptibility to schizophrenia in diverse populations.
|
|
| 3. |
- Theraulaz, Guy, et al.
(författare)
-
Spatial patterns in ant colonies
- 2002
-
Ingår i: Proceedings Of The National Academy Of Sciences Of The United States Of America. - : Proceedings of the National Academy of Sciences. ; 99:15, s. 9645-9649
-
Tidskriftsartikel (refereegranskat)abstract
- The origins of large-scale spatial patterns in biology have been an important source of theoretical speculation since the pioneering work by Turing (1952) on the chemical basis of morphogenesis. Knowing how these patterns emerge and their functional role is important to our understanding of the evolution of biocomplexity and the role played by self organization. However, so far, conclusive evidence for local activation-long-range inhibition mechanisms in real biological systems has been elusive. Here a well-defined experimental and theoretical analysis of the pattern formation dynamics exhibited by clustering behavior in ant colonies is presented. These experiments and a simple mathematical model show that these colonies do indeed use this type of mechanism. All microscopic variables have been measured and provide the first evidence, to our knowledge, for this type of self-organized behavior in complex biological systems, supporting early conjectures about its role in the organization of insect societies.
|
|
| 4. |
- De Koning, H. J., et al.
(författare)
-
Large-scale randomized prostate cancer screening trials : Program performances in the european randomized screening for prostate cancer trial and the prostate, lung, colorectal and ovary cancer trial
- 2002
-
Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 97:2, s. 237-244
-
Tidskriftsartikel (refereegranskat)abstract
- Two large-scale randomized screening trials, the Prostate, Lung, Colorectal and Ovary (PLCO) cancer trial in the USA and the European Randomized Screening for Prostate Cancer (ERSPC) trial in Europe are currently under way, aimed at assessing whether screening reduces prostate cancer mortality. Up to the end of 1998, 102,691 men have been randomized to the intervention arm and 115,322 to the control arm (which represents 83% of the target sample size) from 7 European countries and 10 screening centers in the USA. The principal screening method at all centers is determination of serum prostate-specific antigen (PSA). The PLCO trial and some European centers use also digital rectal examination (DRE) as an ancillary screening test. In the core age group (55-69 years), 3,362 of 32,486 men screened (10%) had a serum PSA concentration of 4 ng/ml or greater, which is I cut-off for biopsy (performed in 84%). An additional 6% was referred for further assessment based on other criteria, with much less efficiency. Differences in PSA by country are largely attributable to the age structure of the study population. The mean age-specific PSA levels are lower in the PLCO trial (1.64 ng/ml [in the age group 55-59 years], 1.80 [60-64 years] and 2.18 [65-69 years) than in the ERSPC trial (1.28-1.71 [55-59], 1.75-2.87 [60-64] and 2.48-3.06 [65-69 years]). Detection rates at the first screen in the ERSPC trial range from II to 42/1,000 men screened and reflect underlying differences in incidence rates and screening procedures. In centers with consent to randomization design, adherence in the screening arm is 91%, but less than half of the men in the target population are enrolled in the trial. In population-based centers in which men were randomized prior to consent, all eligible subjects are enrolled, but only about two-thirds of the men in the intervention arm undergo screening. Considerable progress has been made in both trials. Enrollment will be completed in 2001. A substantial number of early prostate cancers have been detected. The differences between countries seem to reflect both underlying prostate cancer incidence and screening policy. The trials have the power to show definitive results in 2005-2008.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Nicolis, Stamatios C., et al.
(författare)
-
Optimality of collective choices : A stochastic approach
- 2003
-
Ingår i: Bulletin of Mathematical Biology. ; 65:5, s. 795-808
-
Tidskriftsartikel (refereegranskat)abstract
- Amplifying communication is a characteristic of group-living animals. This study is concerned with food recruitment by chemical means, known to be associated with foraging in most ant colonies but also with defence or nest moving. A stochastic approach of collective choices made by ants faced with different sources is developed to account for the fluctuations inherent to the recruitment process. It has been established that ants are able to optimize their foraging by selecting the most rewarding source. Our results not only confirm that selection is the result of a trail modulation according to food quality but also show the existence of an optimal quantity of laid pheromone for which the selection of a source is at the maximum, whatever the difference between the two sources might be. In terms of colony size, large colonies more easily focus their activity on one source. Moreover, the selection of the rich source is more efficient if many individuals lay small quantities of pheromone, instead of a small group of individuals laying a higher trail amount. These properties due to the stochasticity of the recruitment process can be extended to other social phenomena in which competition between different sources of information occurs. (C) 2003 Society for Mathematical Biology. Published by Elsevier Ltd. All rights reserved.
|
|
| 10. |
- Salager, Serge E., et al.
(författare)
-
Influence of the Stirrer Initial Position on Emulsion Morphology. Making Use of the Local Water-to-Oil Ratio Concept for Formulation Engineering Purpose
- 2001
-
Ingår i: Industrial & Engineering Chemistry Research. - 0888-5885 .- 1520-5045. ; 40:22, s. 4808-4814
-
Tidskriftsartikel (refereegranskat)abstract
- The initial location of the stirrer in the emulsification vessel can induce the resulting emulsion type. The interpretation in terms of mixing phenomena leads to the use of the local water-to-oil ratio (WOR) concept in the formulation-compn. map. The know-how assocd. with this phenomenol. allows us to interpret in a straightforward way the kind of complex procedures commonly employed in emulsion manufg., particularly those assocd. with inversion and multiple emulsion attainment. [on SciFinder (R)]
|
|
