The generality of cryptic dietary niche differences in diverse large-herbivore assemblages

Ecological niche differences are necessary for stable species coexistence but are often difficult to discern. Models of dietary niche differentiation in large mammalian herbivores invoke the quality, quantity, and spatiotemporal distribution of plant tissues and growth forms but are agnostic toward food plant species identity. Empirical support for these models is variable, suggesting that additional mechanisms of resource partitioning may be important in sustaining large-herbivore diversity in African savannas. We used DNA metabarcoding to conduct a taxonomically explicit analysis of large-herbivore diets across southeastern Africa, analyzing ∼4,000 fecal samples of 30 species from 10 sites in seven countries over 6 y. We detected 893 food plant taxa from 124 families, but just two families—grasses and legumes—accounted for the majority of herbivore diets. Nonetheless, herbivore species almost invariably partitioned food plant taxa; diet composition differed significantly in 97% of pairwise comparisons between sympatric species, and dissimilarity was pronounced even between the strictest grazers (grass eaters), strictest browsers (nongrass eaters), and closest relatives at each site. Niche differentiation was weakest in an ecosystem recovering from catastrophic defaunation, indicating that food plant partitioning is driven by species interactions, and was stronger at low rainfall, as expected if interspecific competition is a predominant driver. Diets differed more between browsers than grazers, which predictably shaped community organization: Grazer-dominated trophic networks had higher nestedness and lower modularity. That dietary differentiation is structured along taxonomic lines complements prior work on how herbivores partition plant parts and patches and suggests that common mechanisms govern herbivore coexistence and community assembly in savannas

Bilateral vagotomy and gastrojejunostomy for chronic duodenal ulcer

The results in a consecutive series of 248 patients with bilateral vagotomy and gastrojejunostomy for chronic duodenal ulcer after a minimum follow-up period of ten years are presented. 1. Results are assessed as 'excellent' in 66.1%., 'good' in 16.4%., 'improved' in 8.2%., and 'failed' in 9.3%. 2. Stomal ulceration is found in 3.6%, and recurrent ulceration in a further 1.5%. 3. The side effects of the operation are: poor appetite, flatulence, bilious vomiting, diarrhoea, vasomotor symptoms, weight loss, anaemia and pulmonary tuberculosis. With the exception of bilious vomiting and diarrhoea, the incidence of these side effects is low. Although the incidence of bilious vomiting and diarrhoea is high, most cases are mild and are not troublesome to the patient. 4. The severity of the duodenal ulcer does not affect the result of the operation or the incidence of side effects. 5. The non-secretor state predisposes to duodenal ulceration. The association of blood group O with duodenal ulceration, noted by other workers, is not confirmed in this series. 6. The blood group and secretor status do not affect the severity of the ulcer or the outcome of treatment. 7. The blood group and secretor status do not influence the incidence of side effects with the exception of diarrhoea. Diarrhoea occurs with greater frequency in secretors when compared with non-secretors. 8. The age at operation does not affect the result of the operation. 9. The younger the patient, the more likely he is to develop side effects. 10. The longer the history of duodenal ulceration, the better the result of operation. 11. The shorter the history, the more likely is the patient to develop post-operative side effects. The author concludes that bilateral vagotomy and gastrojejunostomy is the operation of choice in patients with chronic duodenal ulcer and should be adopted as the routine surgical procedure in the first instance

Influence of horse stable environment on human airways

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Spatial Dynamics of Nesting Behavior: Lizards Shift Microhabitats to Construct Nests with Beneficial Thermal Properties

Because temperature affects the growth, development, and survival of embryos,oviparous mothers should discriminate carefully among available nesting sites. We combined a radiotelemetric study of animal movements with a spatial mapping of environmental temperatures to test predictions about the nesting behavior of the eastern fence lizard (Sceloporus undulatus). Females made large excursions from their typical home ranges to construct nests in exposed substrates. These excursions appeared to be related solely to nesting because all females returned to forested habitat immediately afterward. On average, 1% (range ¼ 0–8%, n ¼ 19) of the area used by a female during nesting was contained within the area used before and after nesting. The selection of nesting sites matched predictions based on laboratory studies of embryonic performance; specifically, females nested in extremely open habitat at a mean of 6 cm depth. Spatial mapping of soil temperatures revealed that temperatures of nesting areas exceeded those of areas typically used by females, indicating that females preferred to construct warm nests that speed embryonic growth and development. However, this behavior could reduce the survivorship of females because of the need to rapidly navigate unfamiliar and exposed terrain

Osteosarcoma Associated With Diamond-Blackfan Anaemia: A Case of a Child Receiving Growth Hormone Therapy

Purpose: Diamond–Blackfan anaemia (DBA) is a rare pure congenital red cell aplasia, usually presenting in infancy or early childhood. The literature suggests a predisposition to haemopoietic malignancy but in addition solid tumours have been reported, with five cases of osteosarcoma described

Glade cascades: indirect legacy effects of pastoralism enhance the abundance and spatial structuring of arboreal fauna

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117219/1/ecy2013944827.pd

High-Pressure Neutron-Scattering Studies of Graphite and Stage-Two Graphite-SbCl₅

The longitudinal-acoustic (LA) phonons propagating along the c axis in highly oriented pyrolytic graphite (HOPG) were investigated as a function of pressure up to 20 kbar using inelastic-neutron-scattering techniques. The phonon frequencies varied as (P,q)=A(P)sin[c(P)q/2], where A(P) and c(P) indicate the pressure dependences of the zone-center LO frequency of B1g1 symmetry and of the c-axis lattice spacing, respectively. From the measurements, the mode Grüneisen parameter for the LA branch was estimated to be 1.5 x 10-2 kbar-1 (independent of q); the elastic constant C33 for HOPG was found to be 3.40 x 1011 dyn/cm2 at 1 bar with a pressure coefficient of (1/C33)(dC33/dP)=2.91 x 10-2 kbar-1. The measured c-axis spacings were 6.71 and 12.72 Å for HOPG and stage-2 SbCl5-intercalated graphite, respectively, at atmospheric pressure; the corresponding compressibilities (1/c)(dc/dP) were -2.24 x 10-3 kbar-1 (HOPG) and -2.28 x 10-3 kbar-1 (SbCl5). Elastic-neutron-scattering studies up to 20 kbar were undertaken to search for stage transformations, but no evidence of any phase transition was observed