Survival and Growth of American Alligator (Alligator mississippiensis) hatchlings after artificial incubation and repatriation

Hatchling American Alligators (Alligator mississippiensis) produced from artificially incubated wild eggs were returned to their natal areas (repatriated). We compared artificially incubated and repatriated hatchlings released within and outside the maternal alligator’s home range with naturally incubated hatchlings captured and released within the maternal alligator’s home range on Lake Apopka, Lake Griffin, and Orange Lake in Florida. We used probability of recapture and total length at approximately nine months after hatching as indices of survival and growth rates. Artificially incubated hatchlings released outside of the maternal alligator’s home range had lower recapture probabilities than either naturally incubated hatchlings or artificially incubated hatchlings released near the original nest site. Recapture probabilities of other treatments did not differ significantly. Artificially incubated hatchlings were approximately 6% shorter than naturally incubated hatchlings at approximately nine months after hatching. We concluded that repatriation of hatchlings probably would not have long-term effects on populations because of the resiliency of alligator populations to alterations of early age-class survival and growth rates of the magnitude that we observed. Repatriation of hatchlings may be an economical alternative to repatriation of older juveniles for population restoration. However, the location of release may affect subsequent survival and growth

Motor vehicle accidents in patients with an implantable cardioverter-defibrillator

Objectives.This study was designed to examine driving safety in patients at risk for sudden death after implantation of a cardioverter-defibrillator.Background.Cardioverter-defibrillators are frequently implanted in patients at high risk for sudden death. Despite concern about the safety of driving in these patients, little is known about their actual motor vehicle accident rates.Methods.Surveys were sent to all 742 physicians in the United States involved in cardioverter-defibrillator implantation and follow-up. Physicians were questioned about numbers of patients followed up, numbers of fatal and nonfatal accidents, physician recommendations to patients about driving and knowledge of state driving laws.Results.Surveys were returned by 452 physicians (61%). A total of 30 motor vehicle accidents related to shocks from implantable defibrillators were reported by 25 physicians over a 12-year period from 1980 to 1992. Of these, nine were fatal accidents involving eight patients with a defibrillator and one passenger in a car driven by a patient. No bystanders were fatally injured. There were 21 nonfatal accidents involving 15 patients, 3 passengers and 3 bystanders. The estimated fatality rate for patients with a defibrillator, 7.5/100,000 patient-years, is significantly lower than that for the general population (18.4/100,000 patient-years, p < 0.05). The estimated injury rate, 17.6/100,000 patient-years, is also significantly lower than that for the general public (2,224/100,000 patient-years, p < 0.05). Only 10.5% (30 of 286) of all defibrillator discharges during driving resulted in accidents. Regarding physician recommendations, most physicians (58.1%) ask their patients to wait a mean (± SD) of 7.3 ± 3.4 months after implantation or a shock before driving again.Conclusions.The motor vehicle accident rate caused by discharge from an implantable cardioverter-defibrillator is low. Although restricting driving for a short period of time after implantation may be appropriate, excessive restrictions or a total ban on driving appears to be unwarranted

Interaction of Young Florida Sandhill Cranes with Their Parents

We studied the interactions of 46 Florida sandhill crane (Grus canadensis pratensis) chicks and their parents from hatching until the chicks left the family group. Our goal was to see if young remained closer to one parent than the other and if the distance between a chick and its parents increased as the young approached the age of independence. Using a population of individually marked adult pairs, we ranked the distance to and gender of the nearest parent during 233 30-minute observation periods. Between hatching and 180 days of age, chicks showed a greater tendency to be nearer the female than male parent. Before 265 days of age there was a greater probability that the chick would be within 5 m of its nearest parent. After 265 days of age the probability that a chick would be ≥ 20 m from its nearest parent increased. These 2 ages may represent developmental milestones that could have relevance for captive management and reintroduction strategies. By the end of the first stage (180 days), the benefits of being reared by their parents may have peaked for crane chicks and the end of the second stage (265 days) could be the optimal time for releasing captive-reared cranes into the wild

RESPONSE OF FLORIDA SANDHILL CRANES TO NEST INSPECTION

We observed the response of nesting Florida sandhill cranes (Grus canadensis pratensis) to 27 instances of nest inspection. The disturbed bird flew from the area 81% and walked 19% of the time. The median distance moved was 330 meters (range 28 to 480 meters). The median length of time the nest was left unattended following inspection was 50 min (range: 10 to 166 min). The median length of time that observers stayed at the nest was 16 min (range: 5 to 48 min). Ten of the nests inspected (40%) eventually failed to produce young. Statistical analysis was focused on the direction and strength of association between various predictors and 4 disturbance-related outcomes; flying vs. walking, distance moved, time-off-nest, and nest fate. A limited sample size precluded the use of more than 2 predictors simultaneously in any of the statistical models. We found that the farther into incubation the nest was (nest age) the greater the likelihood the incubating bird would fly from the nest (r2=0.28, P= 0.064). Greater time-in nest area was associated with a longer time-off-nest (r2=0.29, P= 0.008). Greater time-in nest area and longer time-off-nest were both univariantely associated with a greater probability of nest failure (r2=0.36, P=0.018 and r2=0.40, P=0.008 respectively). Four variables (time-in-area, time-off-nest, age of nest, whether the disturbed crane or its mate returned to the nest) considered in pair wise combinations were all significantly associated with probability of nest failure (r2 range: 0.46 to 0.72). Longer time-in-area and whether the disturbed bird was the returning bird had the strongest overall association with likely nest failure (r2=0.72, P=0.010). Although the nest failure rate of 44% in the experimental nests was greater than the failure rate of 26% for a concurrently collected sample of control nests, the 2 rates were not significantly different (P=0.353). Based on these results we would recommend that crane nests be inspected in 12-13 min or less. If possible, nest inspections should occur later rather than earlier in the incubation period, carried out in a manner that increases the likelihood that the disturbed bird will walk rather than fly from the nest area, and timed to increase the chance that the non-disturbed bird will be the returning bird

Body Mass Index (BMI) of normal Sandhill Cranes

We used linear and mass measurements to construct a body mass index (BMI) for 2 subspecies of sandhill cranes (Grus canadensis). We found that BMI declined during the spring and early summer period. We used the BMI to show that juvenile Florida sandhill cranes (G. c. pratensis) reach their full mass at about 270 days of age, near the age at which they begin to leave the company of their parents. We used mensural data to predict a minimum expected mass for normal sandhill cranes which could be then used to evaluate the relative health of an individual suspected of being diseased or underweight

The Spectrum of Hand Dysfunction After Hemodialysis Fistula Placement

Contemporary dogma has classically attributed hand dysfunction following hemodialysis arteriovenous fistula (AVF) placement to regional ischemia. We hypothesize that hemodynamic perturbations alone do not entirely explain the postoperative changes in hand function and, furthermore, that various elements of hand function are differentially affected following surgery. Methods: Bilateral wrist and digital pressures and upper extremity nerve conduction tests were recorded preoperatively and at 6 weeks and 6 months following upper extremity AVF construction in 46 patients. Concurrently, biomechanical tests were administered to evaluate multiple limb functional domains, including grip strength, dexterity, sensation, and perception of hand function. Results: Mean participant age was 59 ± 14 years (75% male), and 48% were on hemodialysis at the time of access placement. Of the participants, 69% had a brachial-based AVF, and the remainder had radial-based accesses. Six weeks following AVF placement, a significant decrease in access-side digital pressures was observed, with only partial recovery at 6 months (P < 0.0001). Grip strength was significantly worse in the access-side limb (P = 0.0003), and the Disability of Arm, Shoulder and Hand (DASH) questionnaire score substantially worsened postoperatively (P = 0.06). Digital sensation and limb dexterity did not differ between limb sides (P > 0.1) or change significantly over time (P > 0.1). Principal component analyses demonstrated that nerve conduction parameters tended to track the biomechanical parameters, yet both were relatively independent of the hemodynamic parameters. Discussion: Our findings suggest that ischemia alone does not completely explain access-related hand dysfunction and that future study is needed to elucidate alternative mechanisms