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Timothy O.  Osborne 《Ibis》1981,123(3):289-297
The Red-necked Falcon in southern Zambia is a year-long resident in its breeding territory. The study was conducted on a floodplain and the adjacent acacia savannah in an undisturbed natural environment. The falcon principally nests in natural depressions on frond bases on the leeward side of Borassus Palms but also utilizes old crow and raptor nests. Incubation averaged 33 days and was undertaken by the female. The young fledged after a 36-day nestling period and remained under parental care for up to three weeks after that. Nesting success averaged 1.3 young per nest or 44% of the eggs laid. The post-juvenal moult commenced when the young were five to six months old and continued for six months. Birds comprised 98% of the diet of the falcons. The adults selected larger prey as the nestlings increased in size. The 69-day incubation and nesting period is up to 14 days longer than in similar-sized falcons.  相似文献   
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C4 photosynthesis evolved multiple times independently in angiosperms, but most origins are relatively old so that the early events linked to photosynthetic diversification are blurred. The grass Alloteropsis semialata is an exception, as this species encompasses C4 and non-C4 populations. Using phylogenomics and population genomics, we infer the history of dispersal and secondary gene flow before, during and after photosynthetic divergence in A. semialata. We further analyse the genome composition of individuals with varied ploidy levels to establish the origins of polyploids in this species. Detailed organelle phylogenies indicate limited seed dispersal within the mountainous region of origin and the emergence of a C4 lineage after dispersal to warmer areas of lower elevation. Nuclear genome analyses highlight repeated secondary gene flow. In particular, the nuclear genome associated with the C4 phenotype was swept into a distantly related maternal lineage probably via unidirectional pollen flow. Multiple intraspecific allopolyploidy events mediated additional secondary genetic exchanges between photosynthetic types. Overall, our results show that limited dispersal and isolation allowed lineage divergence, with photosynthetic innovation happening after migration to new environments, and pollen-mediated gene flow led to the rapid spread of the derived C4 physiology away from its region of origin.  相似文献   
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Recently diverged species present particularly informative systems for studying speciation and maintenance of genetic divergence in the face of gene flow. We investigated speciation in two closely related Senecio species, S. aethnensis and S. chrysanthemifolius, which grow at high and low elevations, respectively, on Mount Etna, Sicily and form a hybrid zone at intermediate elevations. We used a newly generated genome‐wide single nucleotide polymorphism (SNP) dataset from 192 individuals collected over 18 localities along an elevational gradient to reconstruct the likely history of speciation, identify highly differentiated SNPs, and estimate the strength of divergent selection. We found that speciation in this system involved heterogeneous and bidirectional gene flow along the genome, and species experienced marked population size changes in the past. Furthermore, we identified highly‐differentiated SNPs between the species, some of which are located in genes potentially involved in ecological differences between species (such as photosynthesis and UV response). We analysed the shape of these SNPs’ allele frequency clines along the elevational gradient. These clines show significantly variable coincidence and concordance, indicative of the presence of multifarious selective forces. Selection against hybrids is estimated to be very strong (0.16–0.78) and one of the highest reported in literature. The combination of strong cumulative selection across the genome and previously identified intrinsic incompatibilities probably work together to maintain the genetic and phenotypic differentiation between these species – pointing to the importance of considering both intrinsic and extrinsic factors when studying divergence and speciation.  相似文献   
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Captive bolt stunning is used for rendering livestock insensible at slaughter. The mechanical factors relating to performance of 6 penetrating captive bolt gun (CBG) models were examined. The Matador Super Sécurit 3000 and the .25 Cash Euro Stunner had the highest kinetic energy values (443 J and 412 J, respectively) of the CBGs tested. Ninety percent (27/30) of CBGs held at a government gun repository (United Kingdom) were found to have performed at a normal standard for the model, while 53% (10/19) of commercial contractor CBGs tested were found to underperform for the gun model. When the .22 Cash Special was fired 500 times at 4 shots per min, the gun reached a peak temperature of 88.8°C after 2.05 hr. Repeat firing during extended periods significantly reduced the performance of the CBG. When deciding on the appropriate CBG/cartridge combination, the kinetic energy delivered to the head of the nonhuman animal, bolt penetration depth, and species/animal type must be considered. It is recommended that CBGs are routinely checked for wear to the bolt and barrel if they are repeatedly fired in a session.  相似文献   
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Introduction

The T allele of a single nucleotide polymorphism (SNP: rs2544390) in lipoprotein receptor-related protein 2 (LRP2) is associated with higher serum urate and risk of gout in Japanese individuals. SNP rs2544390 also interacts with alcohol consumption in determining hyperuricemia in this population. We investigated the association of rs2544390 with gout, and interaction with all types of alcohol consumption in European and New Zealand (NZ) Māori and Pacific subjects, and a Māori study cohort from the East Coast region of NZ’s North Island.

Methods

Rs2544390 was genotyped by Taqman®. From NZ a total of 1205 controls and 1431 gout cases clinically ascertained were used. Publicly available genotype and serum urate data were utilized from the Atherosclerosis Risk in Communities (ARIC) study and the Framingham Heart Study (FHS). Alcohol consumption data were obtained by consumption frequency questions in all study cohorts. Multivariate adjusted logistic regression was done using STATA.

Results

The T allele of rs2544390 was associated with increased risk of gout in the combined Māori and Pacific Island cohort (OR = 1.20, P = 0.009), and associated with gout in the European subjects, but with a protective effect (OR = 0.79, PUnadjusted = 0.02). Alcohol consumption was positively associated with risk of gout in Māori and Pacific subjects (0.2% increased risk/g/week, P = 0.004). There was a non-additive interaction between any alcohol intake and the risk of gout in the combined Māori and Pacific cohorts (PInteraction = 0.001), where any alcohol intake was associated with a 4.18-fold increased risk in the CC genotype group (P = 6.6x10-5), compared with a 1.14-fold increased risk in the CT/TT genotype group (P = 0.40). These effects were not observed in European subjects.

Conclusions

Association of the T-allele with gout risk in the Māori and Pacific subjects was consistent with this allele increasing serum urate in Japanese individuals. The non-additive interaction in the Māori and Pacific subjects showed that alcohol consumption over-rides any protective effect conferred by the CC genotype. Further exploration of the mechanism underlying this interaction should generate new understanding of the biological role of alcohol in gout, in addition to strengthening the evidence base for reduction of alcohol consumption in the management of gout.  相似文献   
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