A statistical study was conducted to test the initial and residual effects of phentolamine, an adrenergic blocking agent, upon the nephridial apparatus of Paramecium. The mean normal rate of ...evacuation for the control organisms was 6.925 cycles/min. After initial exposure to 6 x 10-3M phentolamine, the mean cycling rate was 2.675 cycles/min. After exposure to 2.4 ml of 6 x 103M phentolamine over a four-week period, the mean cycling rate was 5.650 cycles/min. Statistical analysis of the data indicated that the initial application of phentolamine caused a significant depression in the cycling rate of the nephridial apparatus and those organisms cultured in the drug also showed a depression in the cycling rate of this organelle. Both initially and residually, phentolamine caused a disruption in the osmoregulation of the organism as was evidenced either by membrane disruption or extreme vacuolation.
A flexible compensation plan that offers the chance to buy or sell vacation time has great appeal. According to a 1990 survey by A. Foster Higgins & Co. Inc., more than 1/3 of employees are willing ...to change vacation benefits, but only one out of every 5 flex plans provides this option. Many employers shy away from vacation trading options because of increased administrative burdens or potential effects on staffing. Such employers should reconsider vacation trading's positive employee relations impact, design flexibility, potential sizable savings and defined legal requirements. Vacation options allow working parents to elect extra time off to handle family matters. Employees who want a long vacation and newer employees ineligible for much time off can choose the extra time. Advantages for the employer include: 1. Employees appreciate the benefits program more. 2. Employee recruitment is strengthened. 3. Additional flexibility improves the employer's ability to exercise financial controls.
Serum iron concentration and iron-binding capacity were determined in 34 respectively 35 clinically healthy horses of different sex, with the age of 3 to 21 years. In the Warm blooded horse, the Half ...bred, the Haflinger horse, the Heavy horse and the Arabian Haflinger the mean serum iron concentration amounted to 253 +/- 66 micrograms/dl, 202 +/- 87 micrograms/dl, 166 +/- 67 micrograms/dl, 183 micrograms/dl and 366 micrograms/dl, while the iron-binding capacity in the Warm blooded horse, the Half bred, the Haflinger horse, the Thoroughbred, the Heavy horse and the Arabian Haflinger ran up to 427 +/- 55 micrograms/dl, 530 +/- 162 micrograms/dl, 422 +/- 63 micrograms/dl, 447 micrograms/dl, 467 micrograms/dl and 394 micrograms/dl. Regarding serum iron concentration no age or sex differences were ascertained, whereas they were obvious when observing the iron-binding capacity. Diurnal variations in serum iron concentration are pointed out. The quotient of the two examined parameters showed race-related differences. The results are presented in tables.
Published in the Journal of Experimental Biology, v214 p131-146, 2011. Sponsored in part by SERDP, CNO/N45, and NSERC.
Lunge feeding by rorqual whales (Balaenopteridae) is associated with a high ...energetic cost that decreases diving capacity, thereby limiting access to dense prey patches at depth. Despite this cost, rorquals exhibit high rates of lipid deposition and extremely large maximum body size. To address this paradox, we integrated kinematic data from digital tags with unsteady hydrodynamic models to estimate the energy budget for lunges and foraging dives of blue whales (Balaenoptera musculus), the largest rorqual and living mammal. Our analysis suggests that, despite the large amount of mechanical work required to lunge feed, a large amount of prey and, therefore, energy is obtained during engulfment. Furthermore, we suggest that foraging efficiency for blue whales is significantly higher than for other marine mammals by nearly an order of magnitude, but only if lunges target extremely high densities of krill. The high predicted efficiency is attributed to the enhanced engulfment capacity, rapid filter rate and low mass-specific metabolic rate associated with large body size in blue whales. These results highlight the importance of high prey density, regardless of prey patch depth, for efficient bulk filter feeding in baleen whales and may explain some diel changes in foraging behavior in rorqual whales.
Understanding diet is critical for conservation of endangered predators. Southern Resident killer whales (SRKW) (Orcinus orca) are an endangered population occurring primarily along the outer coast ...and inland waters of Washington and British Columbia. Insufficient prey has been identified as a factor limiting their recovery, so a clear understanding of their seasonal diet is a high conservation priority. Previous studies have shown that their summer diet in inland waters consists primarily of Chinook salmon (Oncorhynchus tshawytscha), despite that species' rarity compared to some other salmonids. During other times of the year, when occurrence patterns include other portions of their range, their diet remains largely unknown. To address this data gap, we collected feces and prey remains from October to May 2004-2017 in both the Salish Sea and outer coast waters. Using visual and genetic species identification for prey remains and genetic approaches for fecal samples, we characterized the diet of the SRKWs in fall, winter, and spring. Chinook salmon were identified as an important prey item year-round, averaging ~50% of their diet in the fall, increasing to 70-80% in the mid-winter/early spring, and increasing to nearly 100% in the spring. Other salmon species and non-salmonid fishes, also made substantial dietary contributions. The relatively high species diversity in winter suggested a possible lack of Chinook salmon, probably due to seasonally lower densities, based on SRKW's proclivity to selectively consume this species in other seasons. A wide diversity of Chinook salmon stocks were consumed, many of which are also at risk. Although outer coast Chinook samples included 14 stocks, four rivers systems accounted for over 90% of samples, predominantly the Columbia River. Increasing the abundance of Chinook salmon stocks that inhabit the whales' winter range may be an effective conservation strategy for this population.
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