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The Diederik cuckoo, Chrysococcyx caprius, is a small Afrotropical bird in the family Cuculidae. It is taxonomically related to 13 other species within the genus Chrysococcyx and is migratory in sub‐Saharan Africa. It has a unique breeding behaviour of being a brood parasite: Breeding pairs lay their eggs in the nests of a host species and hatchlings expel the eggs of the host species. The aim of the present study was to investigate diversity in two circadian clock genes, Clock and Adcyap1, to probe for a relationship between genetic polymorphisms and their role in circannual timing and habitat selection (phenology) in intra‐African migrants. DNA extracted from blood was used for the PCR amplification and sequencing of clock genes in 30 Diederik cuckoos. Three alleles were detected for Clock with similar genotypes between individuals from the Northern and Southern breeding ranges while 10 alleles were detected for Adcyap1, having shorter alleles in the North and longer alleles in the South. Population genetic analyses, including allele frequency and zygosity analysis, showed distinctly higher frequencies for the most abundant Clock allele, containing 10 polyglutamine repeats, as well as a high degree of homozygosity. In contrast, all individuals were heterozygous for Adcyap1 and alleles from both regions showed distinct differences in abundance. Comparisons between both clock genes and phenology found several phenotypic correlations. This included evidence of a relationship between the shorter alleles and habitat selection as well as a relationship between longer alleles and timing. In both instances, evidence is provided that these effects may be sex‐specific. Given that these genes drive some of the synchronicity between environments and the life cycles of birds, they provide valuable insight into the fitness of species facing global challenges including climate change, urbanisation and expanding agricultural practices. Samevatting Die Diederik koekoek, Chrysococcyx caprius, is ’n klein Afrotropiese voël in die Cuculidae familie. Dit is taksonomies verwant aan dertien ander spesies in die genus Chrysococcyx en is ’n migrant in sub‐Sahara Africa met die unieke teling fenologie van broeisparasietisme (broeipare lê nul eiers in die neste van gasheerspesies en kuikens verwyder die eiers van hul gashere). Die doelwit van die huidige studie is om diversiteit in twee gene van die sirkadiese klok, Clock en Adcyap1, te ondersoek om moontlike verwantskappe tussen polimorfisme en fenologie soos tydsberekening en habitat keuse te ontleed. DNS vanaf bloed monsters was gebruik vir PKR amplifikasie en reeksbepaling in dertig Diederik koekoek. Drie allele was bespeur vir die Clock geen, met soortgelyke genotipes onder individue van beide die Noordelike en Suidelike teling streke, terwyl tien allele bespeur is vir die Adcyap1 geen, met korter allele in die Noord en langer allele in die Suid. Genetiese analise van die populasies, insluitend alleel frekwensie en sigositeit, het kenmerkend hoër frekwensies getoon vir die mees algemene Clock geen, met tien poli‐glutamien herhalings, sowel as ‘n hoë mate van homosigositeit. In teenstelling was alle individue heterosigoties vir die Adcyap1 geen met afsonderlike verskille in mate. Vergelykings tussen beide gene en fenologie het verskeie korrelasies ontbloot. Onder andere is tekens vir ‘n verwantskap tussen korter allele en habitat seleksie sowel as langer allele en tydsberekening gevind. In beide gevalle is verdere bewyse gelewer dat die effek seks‐spesifiek mag wees. Aangesien hierdie gene die ritmiek van jaarlikse lewensiklusse reguleer verskaf hul belangrike insig tot die fiksheid van spesies wat globale uitdagings die hoof bied. The Diederik cuckoo is a small Afrotropical bird in the Cuculidae family that has a wide geographic distribution in sub‐Saharan Africa. A study on 30 Diederik cuckoos revealed genetic diversity in Clock and Adcyap1 circadian clock genes, with distinct North–South variations in allele lengths. Phenotypic correlations indicated relationships between allele lengths, habitat selection and timing, in a potentially sex‐specific manner, offering valuable insights into the species' adaptation to global challenges.

While African leopard populations are considered to be continuous as demonstrated by their high genetic variation, the southernmost leopard population exists in the Eastern and Western Cape, South Africa, where anthropogenic activities may be affecting this population's structure. Little is known about the elusive, last free-roaming top predator in the region and this study is the first to report on leopard population structuring using nuclear DNA. By analyzing 14 microsatellite markers from 40 leopard tissue samples, we aimed to understand the populations' structure, genetic distance, and gene flow (Nm). Our results, based on spatially explicit analysis with Bayesian methods, indicate that leopards in the region exist in a fragmented population structure with lower than expected genetic diversity. Three population groups were identified, between which low to moderate levels of gene flow were observed (Nm 0.5 to 3.6). One subpopulation exhibited low genetic differentiation, suggesting a continuous population structure, while the remaining two appear to be less connected, with low emigration and immigration between these populations. Therefore, genetic barriers are present between the subpopulations, and while leopards in the study region may function as a metapopulation, anthropogenic activities threaten to decrease habitat and movement further. Our results indicate that the leopard population may become isolated within a few generations and suggest that management actions should aim to increase habitat connectivity and reduce human-carnivore conflict. Understanding genetic diversity and connectivity of populations has important conservation implications that can highlight management of priority populations to reverse the effects of human-caused extinctions.

After decades of near‐complete extirpation, the yellow‐and‐black‐striped Southern Corroboree Frog (Pseudophryne corroboree) is being reintroduced into field enclosures that exclude all but avian predators. The frog's long absence means avian attack risk to reintroduced individuals is unknown, so we asked: does corroboree frog coloration make them vulnerable to predators? First, using painted clay frog models and humans as proxy predators, we found that, surprisingly, striped models were as difficult to detect as control black models, and were far less detectable than yellow models. Second, to quantify attack probabilities, we deployed 2,304 models twice in the species' former range. Of our recovered models, 18% of the striped models were attacked by birds, suggesting they are a significant threat. In our second deployment, we saw a significant reduction in attacks on all model colors with only 10% of striped models attacked. If predators generalize their avoidance learning to real corroboree frogs, strategically timed model deployment near release sites may enhance the probability of survival of reintroduced frogs. Our study suggests that model deployment could be an effective low‐cost technique to increase the survival of reintroduced prey species, including, but not limited to, those potentially conspicuous to their natural enemies.

Cassini's view of Hyperion Saturn's moon Hyperion, an irregular shaped object in a tumbling orbit, looks odd: the Cassini flyby of September 2005 revealed a unique spongy surface. Two papers this week present the initial Cassini results. First, imaging and radio data suggest that the spongy appearance is caused by impact cratering on a porous body. And second, near-infrared and ultraviolet spectroscopy reveal details of the surface composition of the highly reflective areas that cover much of the surface, and also of the darker areas, mostly at the bottom of craters. The spectra are consistent with the presence of water ice contaminated with an organic solid. The low-albedo (dark) material is spectroscopically similar to that found on two other saturnian moons, Iapetus and Phoebe, containing a mixture of water ice, complex organics, carbon dioxide and nitriles. This cocktail of materials resembles those seen in comets and probably in Kuiper Belt objects. The surface of Hyperion has a large region of high albedo with the signature of H 2 O ice and another zone of albedo about a factor of four lower. Observations of the surface in the ultraviolet and near-infrared spectral regions with two optical remote sensing instruments on the Cassini spacecraft detail that the low-albedo material has spectral similarities and compositional signatures that link it with the surface of Phoebe. Hyperion, Saturn’s eighth largest icy satellite, is a body of irregular shape in a state of chaotic rotation 1 , 2 . The surface is segregated into two distinct units. A spatially dominant high-albedo unit having the strong signature of H 2 O ice contrasts with a unit that is about a factor of four lower in albedo and is found mostly in the bottoms of cup-like craters. Here we report observations of Hyperion’s surface in the ultraviolet and near-infrared spectral regions with two optical remote sensing instruments on the Cassini spacecraft at closest approach during a fly-by on 25–26 September 2005. The close fly-by afforded us the opportunity to obtain separate reflectance spectra of the high- and low-albedo surface components. The low-albedo material has spectral similarities and compositional signatures that link it with the surface of Phoebe and a hemisphere-wide superficial coating on Iapetus.

In considering the grid connection of ocean wave energy devices, and in particular, the connection of large offshore arrays, there are a number of technical and economic challenges that need to addressed by wave energy device developers. As device developers approach pre-commercial operation, grid connection factors will become increasingly significant in both technical and financial terms. In this study, some generally applicable, non-device specific challenges are examined. The costing issues involved in procuring, building and maintaining a grid connection are reviewed. The technical impacts on device design and particularly on generator system selection are also examined in detail. A grid connection costing case study in the Irish context is performed as a practical indicator of these issues.

A monolithic BiCMOS-plasmonic transmitter offering 120 GBd NRZ-OOK is demonstrated. The chip comprises an electronic-photonic layer stack. The SiGe BiCMOS electrical layers offer PRBS generation and 4:1 power multiplexing, while the plasmonic layer offers electro-optical modulation at highest speed.

We report on a 40 Gbit/s silicon-organic hybrid (SOH) modulator with 11 dB extinction ratio. A novel electro-optic chromophore with record in-device nonlinearity of 180 pm/V leads to VπL = 0.5 Vmm and a low energy consumption of 1.6 fJ/bit at 12.5 Gbit/s.

We demonstrate a frequency comb generator using silicon-organic hybrid (SOH) electrooptic modulators to obtain flat-top comb spectra. This is the first demonstration of a modulator-based frequency comb generator on silicon. The viability of the device is confirmed in a data transmission experiment achieving an aggregate data rate of 784 Gbit/s.