Home About us Contact
|
Home About us Contact | ||
|
|
||
Duration Longer (duration + longer)
Selected AbstractsChick provisioning rates and growth in Blacklbrowed Albatross Diomedea melanophris and Grey-headed Albatross D. chrysostoma at Bird Island, South GeorgiaIBIS, Issue 4 2000NICOLAS HUIN We compared the parental division of labour and the pattern and rate of parental provisioning by two sympatric species of albatross of similar mass and breeding timetable but differing in diet and in the duration of chick-rearing. Using electronic weighing platforms inside artificial nests, we recorded chick mass of Black-browed Albatross and Grey-headed Albatross at Bird Island, South Georgia every 10 minutes for both species in 1993 and 1994 and for each species in two other years between 1990 and 1996. The chick mass data (nearly one million weighings) were used to calculate meal mass (over 5000 meals) and intervals between meals. Adult birds were fitted with radio-transmitters which allowed each meal to be allocated to the appropriate parent. The combination of meal mass and foraging trip duration were used to calculate provisioning rates for chicks and individual adults. Overall, Black-browed Albatrosses delivered significantly lighter meals (569 g) than Grey-headed Albatrosses (616 g) but more frequently (every 2.07 days and 2.50 days respectively). Thus combining foraging trip data for both parents, Black-browed Albatross chicks received a meal every 1.22 days compared with 1.26 days for Greyheaded Albatross. These rates did not differ significantly. The contribution of each sex of each species in chick provisioning fluctuated between years, being similar in some years or biased towards males in others. Chicks of both species that failed to fledge received smaller, less frequent meals than successful chicks. In 1990 and 1994, Black-browed Albatross chick provisioning rates were lower than in 1992 and 1993. In 1990, both meal mass and trip duration were affected, but only in 1994 was trip duration longer. Greyheaded Albatross chick provisioning rate was lower in 1994 than in other years but trip duration was longer. In each species, significant changes in meal mass and trip duration occurred within the chick-rearing period. Chick provisioning rates invariably declined before chicks attained their peak mass. For both species, chick growth rates and peak and fledging mass, but not fledging age, were affected by differences in provisioning rate. [source] Ca2+ -dependent inactivation of Ca2+ -induced Ca2+ release in bullfrog sympathetic neuronsTHE JOURNAL OF PHYSIOLOGY, Issue 14 2008Tenpei Akita We studied inactivation of Ca2+ -induced Ca2+ release (CICR) via ryanodine receptors (RyRs) in bullfrog sympathetic neurons. The rate of rise in [Ca2+]i due to CICR evoked by a depolarizing pulse decreased markedly within 10,20 ms to a much slower rate despite persistent Ca2+ entry and little depletion of Ca2+ stores. The Ca2+ entry elicited by the subsequent pulse within 50 ms, during which the [Ca2+]i level remained unchanged, did not generate a distinct [Ca2+]i rise. This mode of [Ca2+]i rise was unaffected by a mitochondrial uncoupler, carbonyl cyanide p -trifluromethoxy-phenylhydrazone (FCCP, 1 ,m). Paired pulses of varying interval and duration revealed that recovery from inactivation became distinct , 50 ms after depolarization and depended on [Ca2+]i. The inactivation was prevented by BAPTA (, 100 ,m) but not by EGTA (, 10 mm), whereas the activation was less affected by BAPTA. When CICR was partially activated, some of the non-activated RyRs were also inactivated directly. Thus, the inactivation in these neurons is induced by Ca2+ binding to the high-affinity regulatory sites residing very close to Ca2+ channels and/or RyRs, although the sites for activation are located much closer to those Ca2+ sources. The rate of [Ca2+]i decay after the pulse decreased with increasing pulse duration longer than 10 ms, and this was abolished by BAPTA. Thus, some mechanism counteracting Ca2+ clearance is induced after full inactivation and potentiated during the pulse. Possible models for RyR inactivation were proposed and the roles of inactivation in Ca2+ signalling were discussed. [source] Comparison of potassium-titanyl-phosphate laser vaporization of the prostate and transurethral resection of the prostate: update of a prospective non-randomized two-centre studyBJU INTERNATIONAL, Issue 10 2008Robin Ruszat OBJECTIVES To evaluate the intermediate-term clinical efficacy and the rate of complications in 80 W photoselective vaporization of the prostate (PVP) with the potassium-titanyl-phosphate laser (GreenlightTM, (AMS, Minnetonka, MN, USA) compared with transurethral resection of the prostate (TURP) in a prospective non-randomised two-centre study. PATIENTS AND METHODS From December 2003 to August 2006, 396 patients (PVP 269, TURP 127) with lower urinary tract symptoms secondary to benign prostatic hyperplasia were included in the study. There was a significant difference in mean age (72 years for PVP vs 68 for TURP, P = 0.001). Patients were therefore stratified in age categories (<70, 70,80, >80 years) and compared for perioperative variables, functional outcome and complications, with a follow-up of up to 24 months. RESULTS The mean prostate size was greater (overall, 62 vs 48 mL, P < 0.001) and mean operative duration longer (overall 72 vs 53 min; P = 0.001) for PVP in all age categories. The rate of intraoperative bleeding (3% vs 11%), blood transfusions (0% vs 5.5%) and capsule perforations (0.4% vs 6.3%), and early postoperative clot retention (0.4% vs 3.9%) was significantly lower for PVP. Hospitalization time was significantly shorter in the PVP group for patients aged <70 years (3.0 vs 4.7 days) and 70,80 years (4.0 vs 5.0 days; P = 0.001). The improvement of peak urinary flow rate was higher after TURP for any age category. The International Prostate Symptom Score and postvoid residual volume during the follow-up showed no significant difference. After 12 months the overall prostate size reduction was 63% (,30 mL) after TURP and 44% (,27 mL) after PVP. The rate of repeat TURP/PVP was higher in the PVP group (6.7% vs 3.9%, not significant) within the follow-up of up to 2 years. The incidence of urethral and bladder neck strictures was comparable. CONCLUSIONS PVP was more favourable in terms of perioperative safety. Although patients assigned for PVP were older and had larger prostates, PVP resulted in a similar functional outcome. Further follow-up is needed to draw final conclusions about the long-term efficacy of PVP. [source] Estimation of temporal variation in splash detachment in two Japanese cypress plantations of contrasting ageEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2010Y. Wakiyama Abstract To elucidate splash erosion processes under natural rainfall conditions, temporal variations in splash detachment were observed using a piezoelectric saltation sensor (H11B; Sensit Co., Portland, ND, USA). Preliminary laboratory tests of Sensit suggested that they were suitable for field observations. Field observations were conducted between July and September 2006 in 21- and 36-year-old Japanese cypress (Chamaecyparis obtusa) plantations with mean stand heights of 9·2,m and 17·4,m, respectively. Splash detachment (in g m,2) was measured seven times using splash cups, and raindrop kinetic energy (in J,m,2,mm,1) in both stands was measured using laser drop-sizing (LD) gauges. Sensit was installed to record saltation counts, which were converted to temporal data of splash detachment (splash rate; in g m,2 10,min,1) using the relationship between splash detachment and saltation counts. Surface runoff was monitored using runoff plots of 0·5,m width and 2·0,m length to obtain temporal data of flow depth (in millimeters). Both total splash detachment and raindrop kinetic energy were larger in the older stand. Increased splash rates per unit throughfall were found in both stands after rainless durations longer than approximately one day in both stands. However, a lower splash rate was found in the 21-year stand after rainfall events. During extreme rainstorms, the 21-year stand showed a low runoff rate and a decline in the splash rate, while the 36-year stand showed a higher splash rate and increased flow depth. The piezoelectric sensor proved to be a useful means to elucidate splash erosion processes in field conditions. Copyright © 2010 John Wiley & Sons, Ltd. [source] | ||||||||||