Factors affecting the site of investment, and the reliance on savings for arctic breeders : the capital–income dichotomy revisited

The extent to which migratory birds that breed in the Arctic and winter in southern biomes rely on residual body stores for reproduction is unresolved. The short arctic summer and the limited availability of food early in the season constrain the time available for successful reproduction. Birds that are able to bring sufficient endogenous reserves to the breeding ground to meet, at least partially, the demands of egg-laying can initiate clutch production soon after arrival, thereby shortening the length of the breeding season and improving the chances of reproductive success. The amount of reserves available will be influenced by body size, the increased energetic and predation costs associated with carrying large stores, distances between staging sites and the location of the breeding grounds within the Arctic. Birds need not fly directly to the breeding grounds from the established temperate staging sites. Extensive feeding by migrants may occur in the Arctic, even within a few kilometres of the breeding sites as the birds track the retreating snowline. Irrespective of their size, birds are thus able to store some resources necessary for egg laying at local or regional scales. It is thus important to make a distinction between local capital and distant capital breeding. The extent to which a bird is characterized as a distant capital, local capital, or an income breeder not only varies between species, but also between individuals and seasons.

Unbearable pressures on paradise? : Tourism and heritage management in Luang Prabang, a world heritage site

This article critically appraises and evaluates tourism strategies and heritage management in Luang Prabang, Lao People’s Democratic Republic, a Unesco-designated ‘world heritage’ city. Luang Prabang is widely regarded as one of the most significant heritage cities in Southeast Asia. The city is renowned for its Buddhist and royal culture and also its historic vernacular Lao, French, and Lao-French architecture. The city earned world heritage status in 1995, but since that time the boom in in-bound Asian tourism has put pressures on Luang Prabang’s authenticity and, for some, called into question the validity of its world heritage status. This article examines these substantial and wide-ranging pressures and argues that the growth in tourism and the treatment of Luang Prabang’s heritage are symptoms of broader regional processes of political and economic change, including the expansion of Chinese and Korean investments and the growth of intra-regional tourism. The authors argue that it is unreasonable to expect traditional heritage management mechanisims, including the world heritage listing, to be able to cope with the pressures on sites like Luang Prabang. The very least that is required, the authors contend, is an expanded understanding of the context in which heritage places sit, and the authors make a case that the cultural landscapes approach, combined with explicit concerns for intangible heritage and poverty alleviation, must be at the core of any strategy for long-term protection of the city’s cultural values.

Suburb as site : virtual collaborative learning for undergraduate photography

This paper describes a learning and teaching approach implemented in an undergraduate photography unit that is designed around a virtual collaborative experience. The approach was adopted several years ago and the process of continually refining the approach to enhance the student experience is outlined as are the benefits and challenges that have been encountered to date. The primary aim of the learning and teaching approach is to allow students to develop graduate attributes and technical skills that will prepare them to work in a contemporary media context – working in the virtual so as to understand approaches to developing and presenting work in the modern photography workplace. The approach also aims to engage and support students in a self reflective process where they examine the self and others focusing on aspects of contemporary culture and lifestyle, architecture and concepts of the home. Central to the approach is a virtual collaborative project where students are matched with partners to develop and present a cohesive virtual photography portfolio that contrasts their local environment: Suburb as Site. Finally, the paper describes the research project that is underway to enhance the collaboration matching process and evaluate the student experience. The research aims to contribute to improved staff understanding of the student experience with a view to further enhancing the learning and teaching approach.

Abandoned cubby huts: a site of dreaming and decay

The Cubby Hut is a powerful symbolic structure, an archetypal structure, and a place of imagination, dreams, refuge and adventure. The Cubby is ephemeral and passes from our childhood exploration of the world and into the dreams and memories of adulthood. These cubby huts are primarily built from and located in the landscape and are intrinsically linked to this context; they are landscape as architecture and architecture as landscape and in construction they articulate a connection between the imagination and landscape and decay as they return to the land and the psyche.

Changes in zinc ligation promote remodeling of the active site in the zinc hydrolase superfamily

The zinc hydrolase superfamily is a group of divergently related proteins that are predominantly enzymes with a zinc-based catalytic mechanism. The common structural scaffold of the superfamily consists of an eight-stranded β-sheet flanked by six α-helices. Previous analyses, while acknowledging the likely divergent origins of leucine aminopeptidase, carboxypeptidase A and the co-catalytic enzymes of the metallopeptidase H clan based on their structural scaffolds, have failed to find any homology between the active sites in leucine aminopeptidase and the metallopeptidase H clan enzymes. Here we show that these two groups of co-catalytic enzymes have overlapping dizinc centers where one of the two zinc atoms is conserved in each group. Carboxypeptidase A and leucine aminopeptidase, on the other hand, no longer share any homologous zinc-binding sites. At least three catalytic zinc-binding sites have existed in the structural scaffold over the period of history defined by available structures. Comparison of enzyme-inhibitor complexes show that major remodeling of the substrate-binding site has occurred in association with each change in zinc ligation in the binding site. These changes involve re-registration and re-orientation of the substrate. Some residues important to the catalytic mechanism are not conserved amongst members. We discuss how molecules acting in trans may have facilitated the mutation of catalytically important residues in the active site in this group.

Novel B-site ordered double perovskite Ba2Bi0.1Sc0.2Co1.7O6-x for highly efficient oxygen reduction reaction

Double perovskite Ba₂Bi_0.1Sc_0.2Co_1.7O_6-x (BBSC) demonstrates low polarization resistance between 600 and 750 °C due to the high oxygen reduction rate of BBSC as reflected by its large D_V and k values, which are derived from the face centered cubic structure and high cobalt content.

Small home ranges and high site fidelity in red knots (Calidris c. canutus) wintering on the Banc d’Arguin, Mauritania

Using automated and manual radio-telemetry and resightings of individual colour-ringed birds, we assessed the daily use of space of red knots Calidris canutus canutus at a tropical wintering area along the Sahara coast, the Banc d Arguin in Mauritania. Confirming earlier suggestions, we found that birds were very faithful to their roosts and that the daily foraging range was small; in the course of several winter months birds used an area of only 2 16 km2 of intertidal area. We found no differences between their movements in daylight and at night. Additionally, individuals seem to return to exactly the same locations in subsequent winters. This pattern is very different from red knots wintering in the temperate Wadden Sea. Here, they readily change roost sites and easily cover areas of about 800 km2 in the course of weeks but, just as in Mauritania, no differences between day and night are apparent. In northern Patagonia and north-western Australia, red knots have range sizes closer to those on the Banc d Arguin, but here they do show differences in space use between day and night. Ecological explanations for these contrasting patterns require further comparative data based on in-depth studies on the predictability of the food base and the presence of diurnal and nocturnal predators.

Densities of individually marked migrants away from the marking site to estimate population sizes : a test with three wader populations

Capsule Population estimates based on the mark–resighting method can be a useful alternative to population-wide counts.

Aims To investigate whether the mark–resighting method can be used as an alternative to counts to estimate the size of wader populations.

Methods Individual colour-marking and subsequent resightings allowed accurate estimates of annual survival for three populations of waders, on which basis we could estimate the actual number of marked birds alive. Densities of marked birds were determined on sites away (2000–4300 km) from the ringing locations expecting marked birds to be randomly distributed among non-marked conspecifics. Population sizes are estimated by combining these densities with the number of marked birds alive.

Results We found indications that the distribution of marked birds was indeed random in the locations away from the site of marking. The estimated population size of Red Knot Calidris canutus canutus was in accordance with the most recent estimates based on counts. Our estimate of the Calidris c. islandica population was somewhat lower, and that of the Bar-tailed Godwit Limosa lapponica taymyrensis population was considerably lower than the latest estimates based on counts.

Conclusion Population estimates based on the mark–resighting method can be a useful alternative for, or addition to, population-wide counts, as long as the assumption of random distribution of marked birds at the reading sites is taken into account. We conclude that the Afro-Siberian Bar-tailed Godwit population has recently decreased in size or has been substantially overestimated during the counts.

Yhh1p/Cft1p directly links poly(A) site recognition and RNA polymerase II transcription termination

RNA polymerase II (pol II) transcription termination requires co-transcriptional recognition of a functional polyadenylation signal, but the molecular mechanisms that transduce this signal to pol II remain unclear. We show that Yhh1p/Cft1p, the yeast homologue of the mammalian AAUAAA interacting protein CPSF 160, is an RNA-binding protein and provide evidence that it participates in poly(A) site recognition. Interestingly, RNA binding is mediated by a central domain composed of predicted -propeller-forming repeats, which occurs in proteins of diverse cellular functions. We also found that Yhh1p/Cft1p bound specifically to the phosphorylated C-terminal domain (CTD) of pol II in vitro and in a two-hybrid test in vivo. Furthermore, transcriptional run-on analysis demonstrated that yhh1 mutants were defective in transcription termination, suggesting that Yhh1p/Cft1p functions in the coupling of transcription and 3'-end formation. We propose that direct interactions of Yhh1p/Cft1p with both the RNA transcript and the CTD are required to communicate poly(A) site recognition to elongating pol II to initiate transcription termination.

Phenylalanine-544 plays a key role in substrate and inhibitor binding by providing a hydrophobic packing point at the active site of insulin-regulated aminopeptidase

Inhibitors of insulin-regulated aminopeptidase (IRAP) improve memory and are being developed as a novel treatment for memory loss. In this study, the binding of a class of these inhibitors to human IRAP was investigated using molecular docking and site-directed mutagenesis. Four benzopyran-based IRAP inhibitors with different affinities were docked into a homology model of the catalytic site of IRAP. Two 4-pyridinyl derivatives orient with the benzopyran oxygen interacting with the Zn2+ ion and a direct parallel ring-stack interaction between the benzopyran rings and Phe544. In contrast, the two 4-quinolinyl derivatives orient in a different manner, interacting with the Zn2+ ion via the quinoline nitrogen, and Phe544 contributes an edge-face hydrophobic stacking point with the benzopyran moiety. Mutagenic replacement of Phe544 with alanine, isoleucine, or valine resulted in either complete loss of catalytic activity or altered hydrolysis velocity that was substrate-dependent. Phe544 is also important for inhibitor binding, because these mutations altered the Ki in some cases, and docking of the inhibitors into the corresponding Phe544 mutant models revealed how the interaction might be disturbed. These findings demonstrate a key role of Phe544 in the binding of the benzopyran IRAP inhibitors and for optimal positioning of enzyme substrates during catalysis.