RFamide Peptides in the Leech, Hirudo medicinalis

RFamide peptides have been localized to a number of neuronsof the CNS of the leech, Hirudo medicinalis, using immunocytochemicaltechniques. The majority of this immunoreactivity appears tobe due to the peptide FMRFamide. Most of the identified RFamideimmunoreactive cells are cholinergic motor neurons, though someare interneurons. Superfused FMRFamide is active on the targetsof these identified neurons; in a few well studied cases, ithas been possible to show that FMRFamide mimics a specific physiologicalaction of an identified neuron on its target. In the leech as in other phyla where they occur, RFamide peptidesare widely distributed in neurons, and are neuromodulators withdiverse physiological effects.     

Congenital aganglionic megacolon

Twenty-one pull-through procedures for congenital aganglionic megacolon (Hirschsprung's disease) have been performed at the Los Angeles Children's Hospital since the adoption of the etiological concept of a distal aganglionic segment in 1949. In 14 cases the Swenson procedure as modified by Hiatt was employed, with perineal excision of the colon segment. There were four postoperative deaths and three symptomatic recurrences in this group. Three patients were treated by transabdominal resection of colon and rectum with subsequent pull-through reconstruction (Swenson). Anterior resection (State) was carried out in two cases. Three children with recurrence of symptoms following primary operation were subjected to a secondary pull-through procedure with an eventual successful outcome. The major portion of the postoperative mortality (29 per cent) in this group occurred in infants less than six months of age in whom anastomotic disruption or proximal segment infarction occurred after operation.A study of 31 cases of congenital aganglionic megacolon in very young infants drew attention to the difficulty of establishing a diagnosis in this age group even at exploratory laparotomy. Among these infants the mortality rate was excessive, regardless of the form of therapy employed. Colostomy appeared to be the indicated surgical procedure if a conservative regimen failed to control intractable colonic obstruction during the first year of life.     

Pre-breeding diet influences ornament size in the Rhinoceros Auklet Cerorhinca monocerata

Understanding the mechanisms that influence variation in sexually selected ornaments in seabirds has been challenging owing to the difficulty of capturing and sampling individuals outside of the breeding period when ornaments are usually grown. Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes were used to examine the influence of pre-breeding diet composition on ornament size in the Rhinoceros Auklet Cerorhinca monocerata , a socially monogamous seabird that breeds in the North Pacific. We analysed stable isotopes in adult feathers grown during the pre-alternate moult, which allowed us to infer diet composition during the pre-breeding (February–March) period. Females that fed more on inshore fish had larger horns than females that fed more on euphausiids (also known as krill; Euphausiacea). Body size was a stronger predictor of horn height in males than females, suggesting that ornaments may serve as different signals for each sex. This study provides evidence that diet during the pre-breeding period can influence ornament size and emphasizes the importance of understanding individual ecology throughout the annual cycle for determining the factors that influence mate choice and fitness.     

Traffic Volume Alters Elk Distribution and Highway Crossings in Arizona

ABSTRACT We used 38,709 fixes collected from December 2003 through June 2006 from 44 elk (Cervus elaphus) fitted with Global Positioning System collars and hourly traffic data recorded along 27 km of highway in central Arizona, USA, to determine how traffic volume affected elk distribution and highway crossings. The probability of elk occurring near the highway decreased with increasing traffic volume, indicating that elk used habitat near the highway primarily when traffic volumes were low (<100 vehicles/hr). We used multiple logistic regression followed by model selection using Akaike's Information Criterion to identify factors influencing probability of elk crossings. We found that increasing traffic rates reduced the overall probability of highway crossing, but this effect depended on both season and the proximity of riparian meadow habitat. Elk crossed highways at higher traffic volumes when accessing high quality foraging areas. Our results indicate that 1) managers assessing habitat quality for elk in areas with high traffic-volume highways should consider that habitat near highways may be utilized at low traffic volumes, 2) in areas where highways potentially act as barriers to elk movement, increasing traffic volume decreases the probability of highway crossings, but the magnitude of this effect depends on both season and proximity of important resources, and 3) because some highway crossings still occurred at the high traffic volumes we recorded, increasing traffic alone will not prevent elk-vehicle collisions. Managers concerned with elk-vehicle collisions could increase the effectiveness of wildlife crossing structures by placing them near important resources, such as riparian meadow habitat.