The fecundity costs of building domed nests in birds.

Animal nests provide a beneficial environment for offspring development and as such contribute to fitness. Gathering and transporting materials to construct nests is energetically costly, but the life history trade-offs associated with the types of nests built are largely unknown. Who contributes to building the nest could also mediate these trade-offs, as building a nest as a couple is expected to be less costly per individual than building alone. Using a comparative analysis on 227 songbird species globally, we found a fecundity cost associated with the type of nest a species builds. Species that build domed nests produce fewer broods per year than species building cups or platforms. Dome nesting species also have larger clutch sizes than open nesting species, but only when the nest is built by a couple and not when females build nests alone. This suggests that building domed nests represents a trade-off with investment in young, especially when females are solely responsible for nest building. More broadly, our results could explain macroevolutionary patterns, such as the recent finding that females, building on their own, more often build open cup rather than domed nests.

Management of chronic heart failure in general practice in Australia.

BACKGROUND: Chronic heart failure is a common clinical syndrome associated with high healthcare system use. OBJECTIVE: The aim of this study was to explore the management of chronic heart failure in Australian general practice. METHODS: Data from the Bettering the Evaluation and Care of Health program were used to determine the prevalence of chronic heart failure, use of natriuretic peptide testing, prescribing patterns, hospitalisation rates and referrals to community-based heart failure management programs in three study periods between 2010 and 2015. RESULTS: Data on 8989 patients from 308 general practitioners were analysed. Of these patients, 324 had chronic heart failure (prevalence 3.6%; 95% confidence interval [CI]: 3.1-4.2), 44% (95% CI: 34.5-53.6) of whom had been hospitalised for the condition. The mean number of prescribed heart failure medication agents was 2.26 (95% CI: 2.13-2.39) per patient. Discharge under community heart failure programs was not routine. DISCUSSION: Chronic heart failure is a significant burden in general practice. Strategies to optimise management and avoid hospitalisation, where possible, are needed.

The role of climatic variables on nest evolution in tanagers.

Avian nests are fundamental structures in avian reproduction and face strong selective forces. Climatic conditions are likely to have shaped the evolution of specific nest traits, but evidence is scarce at a macroevolutionary level. The Thraupidae family (commonly known as tanagers) is an ideal clade to understand the link between nest architecture and climate because it presents wide variation in nest traits. To understand whether climatic variables have played a role in the diversification of nest traits among species in this family, we measured nests from 49 species using museum collections. We observed that dome-nesting species are present in dryer and hotter environments, in line with previous findings suggesting that domed nests are a specialisation for arid conditions. We also found evidence that nests with thicker walls are present in locations with lower precipitation and that solar radiation can influence the shape of domed nests; birds tend to build shorter and narrower domes in areas with high levels of solar radiation. Open nest architecture is also potentially influenced by wind speed, with longer and deeper nests in areas characterised by strong winds. Our results support the hypothesis that different climatic variables can drive the evolution of specific aspects of nest architecture and contribute to the diversity of nest shapes we currently observe. However, climatic variables account only for a small fraction of the observed structural variation, leaving a significant portion still unexplained.

Failure of conservative management after the passage of a distal colonic "cast": report of a case.

PURPOSE: The spontaneous passage per rectum of a full-thickness colon "cast" is a rare consequence of acute colonic ischemia. Previous cases have undergone surgery soon afterward because of intractable symptoms. We report a patient who was managed conservatively for 11 months but ultimately required definitive surgery. METHODS: The clinical, radiographic, pathologic, and endoscopic findings were obtained from the case notes and compared with previously reported cases. RESULTS: A 67-year-old obese patient underwent a Hartmann's procedure for a perforated diverticular abscess, which was reversed six months later. On the first postoperative night after the reversal, she had a brief hypotensive episode, and three weeks later passed a 21-cm, full-thickness infarcted piece of colon. She did not develop peritonitis and for 11 months experienced only mild symptoms. Under colonoscopic surveillance, the granulation tissue conduit connecting the remaining viable bowel became increasingly stenosed proximally and difficult to dilate. After three rapidly consecutive episodes of large-bowel obstruction, she required a laparotomy to resect the stricture and restore bowel continuity. From a literature review, this is the eighth case of its kind and the first in which such prolonged conservative management has been possible. CONCLUSIONS: When symptoms permit, it is feasible to manage patients conservatively in the short-term after this unusual event to allow recovery from the initial insult and planning of future surgery. However, definitive treatment is surgical and colonoscopic management should not delay this once the patient is fit for surgery.