No abstract is provided for this article.
Neurofibromatosis is a relatively common inherited disease of the nervous system, with a frequency of almost 1 in 3000. It is associated with a wide range of vascular abnormalities. A 62-year-old man with neurofibromatosis presented to us with a sacral haematoma. This was due to spontaneous rupture of a pre-existing neurofibromata. Upon admission the patient was in hypovolaemic shock and required aggressive resuscitation prior to surgery. Haemorrhage following trauma or spontaneous rupture is an uncommon complication of neurofibromatosis. The management is discussed with emphasis on the cause and control of bleeding from these lesions.
Circadian rhythms in gut microbiota composition are crucial for metabolic function, yet the extent to which they govern microbial dynamics compared to seasonal and lifetime processes remains unknown. Here, we investigate gut bacterial dynamics in wild meerkats ( Suricata suricatta ) over a 20-year period to compare diurnal, seasonal, and lifetime processes in concert, applying ratios of absolute abundance. We found that diurnal oscillations in bacterial load and composition eclipsed seasonal and lifetime dynamics. Diurnal oscillations were characterised by a peak in Clostridium abundance at dawn, were associated with temperature-constrained foraging schedules, and did not decay with age. Some genera exhibited seasonal fluctuations, whilst others developed with age, although we found little support for microbial senescence in very old meerkats. Strong microbial circadian rhythms in this species may reflect the extreme daily temperature fluctuations typical of arid-zone climates. Our findings demonstrate that accounting for circadian rhythms is essential for future gut microbiome research.
NASA’s Structure and Evolution of the Universe (SEU) program uses X-ray and Gamma ray observations to observe the extremes of gravity throughout the universe. This program will probe the nature of black holes, ultimately obtaining a direct image of the event horizon. It will investigate the large scale structure of the Universe to constrain the location and nature of dark matter. Finally it will search for and study the highest energy processes, that approach those found in the early universe.
Driven by the malaria-protective effect of sickle-cell trait, balancing selection results in hemoglobin S equilibrium allele frequencies of between 15% and 20% in areas of high Plasmodium falciparum transmission in sub-Saharan Africa. From this we estimate that the malaria-attributable childhood mortality in the pretreatment era was between 15% and 24%.
Cooperative breeding systems, in which non-breeding individuals provide care for the offspring of dominant group members, occur in less than 1% of mammals and are associated with social monogamy and the production of multiple offspring per birth (polytocy). Here, we show that the distribution of alloparental care by non-breeding subordinates is associated with habitats where annual rainfall is low. A possible reason for this association is that the females of species found in arid environments are usually polytocous and this may have facilitated the evolution of alloparental care.
