The function of extrapair paternity in blue tits and great tits: good genes or fertility insurance?

DNA fingerprinting of an island population of blue tits andgreat tits in southeast Norway revealed that extrapair paternityaccounted for 36% (17/47) and 27% (15/55) of broods and for7% (31/466) and 8% (33/408) of young in the two species, respectively.Cuckolded males did not differ from noncuckolded males withrespect to morphology, age, or survival. There was no seasonalpattern in the frequency of extrapair paternity, and males showedno individual consistency in paternity loss over multiple broods.Extrapair offspring did not grow faster, they did not fledgewith a higher body mass, and they did not show a higher localsurvival rate than their half siblings. Hence, there was noevidence of any association between extrapair paternity andmale phenotypic or genotypic quality. Extrapair offspring wererandomly distributed among broods, with the only exceptionsof one blue tit and two great tit broods in which all young(six to nine) were sired by an extrapair male. This patternis best explained by a small proportion of males (2%–4%)being infertile and by most females performing a few extrapaircopulations as insurance against laying infertile eggs. We concludethat the results suggest a role for fertility insurance butthat alternative functional explanations to extrapair paternityin these populations cannot yet be ruled out.     

Complex Adaptive Systems and the Evolution of Reciprocation

Complex adaptive systems play a major role in the theory of reciprocal altruism. Starting with Axelrod's celebrated computer tournaments, a wide variety of computer simulations show that cooperation can evolve in populations of selfish agents, both with direct and indirect reciprocation. Received 14 April 1998; accepted 16 June 1998.     

Association between periodontitis and vitamin D status: A case-control study

Vitamin D deficiency and periodontitis are commonly prevalent among Saudi adults. However, the association between periodontitis and vitamin D status has not been well documented. This study aims to examine the association between periodontitis and vitamin D status among adults in the Albaha region of Saudi Arabia. A case-control study of 123 Saudi adults was conducted; 60 had severe or moderate periodontitis, and 63 were periodontally healthy. Data was collected by an online self-reported sociodemographic questionnaire. All participants then underwent a full periodontal examination. Blood samples were also provided to assess participants’ vitamin D statuses through serum levels of 25-hydroxyvitamin D (25(OH)D). A total of 60 cases and 63 controls matched for BMI (30.2 ± 4.86 kg/m²), age (40.01 ± 7.73 years), and sex (46.3% and 53.7% male and female, respectively) participated in the study. Mean levels of 25(OH)D were significantly lower in periodontitis participants than in controls (25.03 ± 8.55 ng/ml, 29.19 ± 12.82 ng/ml, p = 0.037, respectively). Lower odds of periodontitis were detected per unit of 25(OH)D level (OR 0.964, 95% CI; 0.931–0.999, p = 0.043). In conclusion, periodontitis is significantly associated with deficient and insufficient levels of vitamin D among Saudi adults in the Albaha region. Future longitudinal research with a larger sample size may be suggested to confirm these results.     

Decrease of hepatic mono and oligo adenosine diphosphoribose content and augmentation of [14C]ribose incorporation during induction of growth by bovine growth hormone in hypophysectomized rats

Following $\text{in}\text{vivo}$ pulse labeling with [¹⁴C]ribose the specific radioactivities of mono- and polyadenosine diphosphoribose, NAD and adenine nucleotides were determined in livers of hypophysectomized Long Evans rats. These analyses were also performed after induction of growth with four successive daily injections of bovine growth hormone. As a consequence of brief treatment with growth hormone polyadenosine diphosphoribose content markedly diminished whereas its specific radioactivity increased. NAD concentration did not vary but its specific radioactivity increased similarly to that of the homopolymer. The steady state concentration of adenine nucleotides remained unchanged, except for ATP which decreased, and their specific radioactivities uniformly decreased.     

DISSECTING SELECTION ON FEMALE MATING PREFERENCES DURING SECONDARY CONTACT

Population-specific preferences involved in premating isolation may be based on several different types of mating cues. Here, we compare the rates of spread of 12 different mating preferences that reflect preferences for local adaptation, male condition, and reinforcement. We introduce methods to dissect the components of the rate of spread to determine why certain mating preferences spread more quickly than others. We confirm the result that female preferences based on population-specific markers alone always spread faster than female preferences based only on a single local adaptation locus, regardless of the strength of natural selection on hybrid incompatibility. However, we find that this occurs for different reasons depending on the strength of selection against hybrids. Female preferences based on total male condition also achieved high rates of spread, suggesting that preferences for condition-dependent male displays may evolve under reinforcement scenarios.     

National Celebration or Local Act of Reconciliation? Public Ritual Performance and Inter-Ethnic Relations in an Australian City

This is a study of the reshaping of Australia Day celebrations in Lismore, a small city in New South Wales, which was motivated by an attempt to make the celebrations inclusive of Indigenous people and to portray the Australian nation as unified rather than divided along lines of race and culture. It shows how and why a group of local people went about reconstructing the Day's events, and how this helped to shape (but not to homogenise) the symbolic messages conveyed. The analysis demonstrates how the specific changes were located structurally both in local initiatives concerning the relationship between Indigenous and White Australians, and also in a wider State and Federal context affecting this relationship. The nature and significance of the changes made to Australia Day are analysed by drawing on the anthropology of performance and other work on public ritual.     

Studies on vitamin D3 metabolism. Discrete liver cytosolic binding proteins for vitamin D3 and 25-hydroxyvitamin D3

Two separate liver cytosolic proteins have been partially purified and identified by their selectivity for binding either [1α,2α(n)-³H]vitamin D₃ or 25-hydroxy [26(27)-methyl-³H]vitamin D₃. The chromatographic properties of the two proteins were not distinguishable by ion-exchange nor were they dependent upon the vitamin D₃ nutritional status of the birds. However, in molecular exclusion chromatography, the binding proteins can be successfully resolved into two discrete entities. Their binding properties suggest that they are not identical with plasma vitamin D₃ binding protein.     

An Active Self-Optimizing Multiplayer Gaming Architecture

Multiplayer games are representative of a large class of distributed applications that suffer from redundant communication, bottlenecks, single points of failure and poor reactivity to changing network conditions. Many of these problems can be alleviated through simple network adaptations at the infrastructure level. In this paper, we describe a model in which game packets are directed along the edges of a rooted tree connecting the players, aggregated during the upstream flight and multicast from the root to the leaves. This tree is constructed based on a heuristic, and can dynamically adjust itself in response to changes in network conditions. This gaming infrastructure is built and maintained using active networks, which is currently the only open architecture suitable for these types of applications. We have designed and implemented a prototype using ANTS that performs these adaptations for unmodified DOOM clients. We present analytical and simulation results that illustrate the reduction in communication overhead, and show that the multicast tree can quickly adjust to changing network conditions. The overhead of the active network-based middleware is acceptable, especially in wide-area networks.