More maximal arcs in Desarguesian projective planes and their geometric structure

In a previous paper R. Mathon gave a new construction method for maximal arcs in finite Desarguesian projective planes via closed sets of conics, as well as giving many new examples of maximal arcs. In the current paper, new classes of maximal arcs are constructed, and it is shown that every maximal arc so constructed gives rise to an infinite class of maximal arcs. Apart from when they are of Denniston type or dual hyperovals, closed sets of conics are shown to give maximal arcs that are not isomorphic to the known constructions. An easy characterisation of when a closed set of conics is of Denniston type is given. Results on the geometric structure of the maximal arcs and their duals are proved, as well as on elements of their collineation stabilisers.

Leaders and their treatment of subgroups: implications for evaluations of the leader and the superordinate group

This experiment examined members' evaluations of a group leader and the group in contexts where a superordinate group comprised two subgroups and the group leader was aligned with one or other subgroup. The design varied group leader (ingroup, outgroup) and leader behavior (ingroup favoring, outgroup favoring) as well as the broader comparative context (intragroup, intergroup). Across a number of measures, results indicated a consistent Group Leader x Leader Behavior interaction that was independent of comparative context. Although group members were most satisfied with an ingroup leader who favored the ingroup, ingroup leaders were perceived positively irrespective of their behavior Outgroup leaders who unexpectedly favored the other subgroup were also perceived positively. However, outgroup leaders who favored their own subgroup were perceived as less fair and as more biased than other leaders. They also engendered less identification with the superordinate group and a less unified perception of the group. Results demonstrate the importance of social identity concerns to leadership in nested group contexts and emphasize the fact that perceptions of leader fairness and concern for the common group mediate responses to the superordinate category. Copyright (C) 2003 John Wiley Sons, Ltd.

On the spectrum of non-Denniston maximal arcs in PG(2,2h)

In 1969, Denniston gave a construction of maximal arcs of degree n in Desarguesian projective planes of even order q, for all n dividing q. Recently, Mathon gave a construction method that generalized that of Denniston. In this paper we use that method to give maximal arcs that are not of Dermiston type for all n dividing q, 4 < n < q/2, q even. It is then shown that there are a large number of isomorphism classes of such maximal arcs when n is approximately rootq. (C) 2003 Elsevier Ltd. All rights reserved.

Nucleocapsid gene variability reveals two subgroups of Lettuce necrotic yellows virus

The complete nucleocapsid (N) genes of eight Australian isolates of Lettuce necrotic yellows virus (LNYV) were amplified by reverse transcription PCR, cloned and sequenced. Phylogenetic analyses of these sequences revealed two distinct subgroups of LNYV isolates. Nucleotide sequences within each subgroup were more than 96% identical but heterogeneity between groups was about 20% at the nucleotide sequence level. However, less than 4% heterogeneity was noted at the amino acid level, indicating mostly third nucleotide position changes and a strong conservation for N protein function. There was no obvious geographical or temporal separation of the subgroups in Australia.

Efficacy of B vitamins in lowering homocysteine in older men - Maximal effects for those with B-12 deficiency and hyperhomocysteinemia

Background and Purpose - A higher plasma concentration of total homocysteine (tHcy) is associated with a greater risk of cardiovascular events. Previous studies, largely in younger individuals, have shown that B vitamins lowered tHcy by substantial amounts and that this effect is greater in people with higher tHcy and lower folate levels. Methods - We undertook a 2-year, double-blind, placebo-controlled, randomized trial in 299 men aged >= 75 years, comparing treatment with a daily tablet containing 2 mg of folate, 25 mg of B-6, and 400 mu g of B-12 or placebo. The study groups were balanced regarding age (mean +/- SD, 78.9 +/- 2.8 years), B vitamins, and tHcy at baseline. Results - Among the 13% with B12 deficiency, the difference in mean changes in treatment and control groups for tHcy was 6.74 mu mol/L (95% CI, 3.94 to 9.55 mu mol/L) compared with 2.88 mu mol/L (95% CI, 0.07 to 5.69 mu mol/L) for all others. Among the 20% with hyperhomocysteinaemia, the difference between mean changes in treatment and control groups for men with high plasma tHcy compared with the rest of the group was 2.8 mu mol/L (95% CI, 0.6 to 4.9 mu mol/L). Baseline vitamin B12, serum folate, and tHcy were significantly associated with changes in plasma tHcy at follow-up (r = 0.252, r = 0.522, and r = -0.903, respectively; P = 0.003, <0.001, and <0.001, respectively) in the vitamin group. Conclusions - The tHcy-lowering effect of B vitamins was maximal in those who had low B12 or high tHcy levels. Community-dwelling older men, who are likely to be deficient in B12 or have hyperhomocysteinemia, may be most likely to benefit from treatment with B vitamins.

Maximal triangle trades with foundation 5 (mod 6) - the final case

The maximum possible volume of a simple, non-Steiner (v, 3, 2) trade was determined for all v by Xhosrovshahi and Torabi (Ars Combinatoria 51 (1999), 211-223), except that in the-case v equivalent to 5 (mod 6), v >= 23, they were only able to provide an upper, bound on the volume. In this paper we construct trades with volume equal to that bound for all v equivalent to 5 (mod 6), thus completing the problem.

Systematic inflammatory responses to maximal versus submaximal lengthening contractions of the elbow flexors

We compared changes in markers of muscle damage and systemic inflammation after submaximal and maximal lengthening muscle contractions of the elbow flexors. Using a cross-over design, 10 healthy young men not involved in resistance training completed a submaximal trial (10 sets of 60 lengthening contractions at 10% maximum isometric strength, 1 min rest between sets), followed by a maximal trial (10 sets of three lengthening contractions at 100% maximum isometric strength, 3 min rest between sets). Lengthening contractions were performed on an isokinetic dynamometer. Opposite arms were used for the submaximal and maximal trials, and the trials were separated by a minimum of two weeks. Blood was sampled before, immediately after, 1 h, 3 h, and 1-4 d after each trial. Total leukocyte and neutrophil numbers, and the serum concentration of soluble tumor necrosis factor-alpha receptor 1 were elevated after both trials (P < 0.01), but there were no differences between the trials. Serum IL-6 concentration was elevated 3 h after the submaximal contractions (P < 0.01). The concentrations of serum tumor necrosis factor-alpha, IL-1 receptor antagonist, IL-10, granulocyte-colony stimulating factor and plasma C-reactive protein remained unchanged following both trials. Maximum isometric strength and range of motion decreased significantly (P < 0.001) after both trials, and were lower from 1-4 days after the maximal contractions compared to the submaximal contractions. Plasma myoglobin concentration and creatine kinase activity, muscle soreness and upper arm circumference all increased after both trials (P < 0.01), but were not significantly different between the trials. Therefore, there were no differences in markers of systemic inflammation, despite evidence of greater muscle damage following maximal versus submaximal lengthening contractions of the elbow flexors.