Environmental Factors Affecting Predation Rates of Mysis relicta

1982 ◽  
Vol 39 (1) ◽  
pp. 203-208 ◽  
Author(s):  
Scott D. Cooper ◽  
Charles R. Goldman
Keyword(s):  
Feeding Rate ◽  
Bright Light ◽  
Time Of Day ◽  
Clearance Rates ◽  
Mysis Relicta ◽  
Factors Affecting ◽  
Feeding Experiments ◽  
Opossum Shrimp ◽  
Consumption Rates ◽  
Low Levels

Mysis relicta was fed Epischura nevadensis late instars or Diaptomus tyrrelli males in a series of feeding experiments. Mysis clearance rates were not affected by the time of day mysids were collected, the time of day experiments were conducted, or conditioning of experimental water by predators and prey. Mysis fed as efficiently in the dark as in bright light, and exhibited increasing clearance rates with increasing container size. When Diaptomus males were used as prey Mysis clearance rates were significantly higher at 5 °C than 10 and 15 °C; temperature did not affect clearance rates with Epischura as prey. Mean clearance rates tended to decline with increasing prey density, but the only significant differences were recorded when Epischura was used as prey. Prior acclimation to experimental light and temperature conditions had no effect on the results. When presented with an abundant food supply, freshly collected Mysis fed at initially low rates. Subsequent feeding rate peaks were followed by feeding rate declines to low levels over a 24-h period. Individual Mysis consumption rates remained relatively constant from day to day.Key words: Mysis relicta, predation, copepods, clearance rates, opossum shrimp

Opossum Shrimp (Mysis relicta) Predation on Zooplankton

1980 ◽  
Vol 37 (6) ◽  
pp. 909-919 ◽  
Author(s):  
Scott D. Cooper ◽  
Charles R. Goldman
Keyword(s):  
Mechanical Efficiency ◽  
Food Selectivity ◽  
Clearance Rates ◽  
Total Consumption ◽  
Mysis Relicta ◽  
Opossum Shrimp ◽  
Consumption Rates ◽  
Food Particles ◽  
Prey Escape ◽  
Comparison Of The Results

Mysis relicta clearance rates were not affected by changes in prey and predator density in single-prey systems where Epischura nevadensis late instars were used as food. A comparison of the results obtained from single-, two-prey, and multiple-prey systems revealed that Mysis clearance rates of E. nevadensis late instars and Diaptomus tyrrelli males were significantly affected by the presence and abundance of alternative prey.When offered natural prey assemblages, the smallest Mysis preyed preferentially on the smallest available prey (Bosmina, Ceriodaphnia, Diaptomus nauplii) while larger Mysis showed an increased preference for larger prey (Epischura, Daphnia). In general, Mysis preferred Daphnia over copepods; Epischura, Ceriodaphnia, Bosmina, and cyclopoid copepods over Diaptomus copepodites and adults; and Diaptomus males over Diaptomus females. Total consumption rates increased with increasing predator size and starvation duration. Food selectivity patterns exhibited by Mysis were attributed to the mechanical efficiency with which the predators captured and handled food particles of different sizes, to the vigor of prey escape responses, and to predator–prey encounter frequencies.Key words: Mysis relicta, predation, zooplankton, feeding preferences, opossum shrimp

Predation by three glacial opportunists on natural zooplankton communities

1986 ◽  
Vol 64 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Redwood W. Nero ◽  
W. Gary Sprules
Keyword(s):  
Previous Survey ◽  
Clearance Rates ◽  
Mysis Relicta ◽  
Chydorus Sphaericus ◽  
Theoretical Comparison ◽  
Feeding Experiments ◽  
Predatory Impact ◽  
Limnocalanus Macrurus ◽  
Zooplankton Communities

We examine the influence of three glacial opportunist predators, Mysis relicta, Limnocalanus macrurus, and Senecella calanoides, on natural zooplankton communities of central Ontario through a series of feeding experiments in small enclosures (23.6 L). Estimates of in situ clearance rates by M. relicta match previously determined rates, with the following gradation of values: Asplanchna sp. > daphnids and bosminids > Epischura lacustris > large cyclopoids, Chydorus sphaericus and small Diaptomus sp. > L. macrurus > S. calanoides. Clearance rates by M. relicta are similar for all daphnids and bosminids. Hypolimnetic species like Daphnia longiremis and Eubosmina longispina are apparently eliminated by M. relicta, while similarly vulnerable species survive because they have an epilimnetic refuge from M. relicta. Limnocalanus macrurus and S. calanoides prey primarily on copepods, Diaphanosoma spp., and rotifers in the hypolimnion. When both clearance rates and population densities of M. relicta, L. macrurus, and S. calanoides are taken into account, the total predatory impact of M. relicta is much larger than that of the two relict copepods. Based on a theoretical comparison of measured clearance rates by predators with estimated rates of prey recruitment, we conclude that differences in species composition and abundance between relict and nonrelict lakes described in a previous survey are due principally to predation by M. relicta.

scholarly journals Public Response, Anxiety and Behaviour during the First Wave of COVID-19 Pandemic in Saudi Arabia

2021 ◽  
Vol 18 (9) ◽  
pp. 4628
Author(s):  
Amani Salem Alqahtani ◽  
Meshael Mohammed Alrasheed ◽  
Ada Mohammed Alqunaibet
Keyword(s):  
Cross Sectional ◽  
Protective Measures ◽  
Policy Makers ◽  
Factors Affecting ◽  
Public Response ◽  
Social Events ◽  
Phone Survey ◽  
Younger Age ◽  
Low Levels ◽  
The Government

This study aims to investigate public response attitude, anxiety, practices and trust in the authorities’ mitigation plan during the first wave of COVID-19 pandemic. A national cross sectional phone survey was conducted among Saudi residents aged 16 years and above. A total of 90,421 (45.2%) individuals participated in the study. Of those, the overall rate of COVID-19 correct knowledge was 82% (mean: 9.84); social media was the most reported source of knowledge. Younger age, low levels of education and foreign residents were associated with poor knowledge. Overall, 49.5% scored 5 or more on the GAD-7 test, indicating anxiety symptoms, 19.2% of them scored 10 and above, suggesting moderate to severe anxiety. Majority of participants (>78%) trusted and supported the interventions implemented by the government to control COVID-19. Social distancing practices among participants was as following, 72.5% stayed at home and avoid going out for nonessential business and 49.5% avoided attending social events and family gatherings. Trust in authorities, being anxious, worry and levels of knowledge about the disease, were the most common factors affecting adoption of the recommended practices. Continuous evaluation of public response about COVID-19, and the effectiveness of protective measures is essential to better inform policy-makers and identify ways of encouraging behaviour change among public during pandemic.

What Are the Factors Affecting Total Sleep Time During Video Polysomnography in Infants?

2020 ◽  
Author(s):  
Grace R. Paul ◽  
Don Hayes ◽  
Dmitry Tumin ◽  
Ish Gulati ◽  
Sudarshan Jadcherla ◽  
...  
Keyword(s):  
Total Sleep Time ◽  
Sleep Time ◽  
Time Of Day ◽  
Apnea Hypopnea Index ◽  
Clinical Factors ◽  
Initial Management ◽  
Factors Affecting ◽  
Modifiable Factors ◽  
Key Points ◽  
Medical Complexity

Objective The aim of the study is to investigate factors affecting total sleep time (TST) during infant polysomnography (PSG) and assess if <4 hours of TST is sufficient for accurate interpretation. Study Design Overall, 242 PSGs performed in 194 infants <6 months of chronological age between March 2013 and December 2015 were reviewed to identify factors that affect TST, including age of infant, location and timing of study, presence of medical complexity, and presence of nasal tubes. A continuum of apnea-hypopnea index (AHI) in relation to TST was reviewed. Data were examined in infants who had TST <4 hours and low AHI. Results Greater TST (p < 0.001) was noted among infants during nocturnal PSGs, at older chronological and post-menstrual ages, and without medical complexity. The presence of nasogastric/impedance probes reduced TST (p = 0.002). Elevated AHIs were identified even in PSGs with TST <4 hours. Short TST may have affected interpretation and delayed initial management in one infant without any inadvertent complications. Conclusion Clinical factors such as PMA and medical complexity, and potentially modifiable factors such as time of day and location of study appeared to affect TST during infant PSGs. TST < 4 hours can be sufficient to identify high AHI allowing physician interpretation. Key Points

Factors affecting pollinator visitation and reproductive success in Sonneratia caseolaris and Aegiceras corniculatum in a mangrove forest in India

2001 ◽  
Vol 17 (3) ◽  
pp. 431-447 ◽  
Author(s):  
SHALINI PANDIT ◽  
B. C. CHOUDHURY
Keyword(s):  
Reproductive Success ◽  
Mangrove Forest ◽  
Time Of Day ◽  
Pollinator Visitation ◽  
Aegiceras Corniculatum ◽  
Factors Affecting ◽  
Plant Reproductive Success ◽  
Sonneratia Caseolaris ◽  
Exclusion Experiments ◽  
Selfing Species

Pollinator visitation to, and the reproductive success of, Sonneratia caseolaris (Sonneratiaceae) and Aegiceras corniculatum (Myrsinaceae) was investigated in a mangrove forest in India. S. caseolaris was shown to be primarily outcrossed and A. corniculatum was shown to be a selfing species. The flowers of both plant species attracted several diurnal and nocturnal visitors. Earlier reports had indicated that S. caseolaris flowered for one night and was exclusively night-pollinated. But flowers of this species were found to be in bloom both at night and during the day, and diurnal visitors to the flowers were more diverse and frequent than nocturnal ones. This was related to the higher volume and energy value of nectar in the morning. The effects of time of day and temperature on visitation rates were quantified. The importance of visitors to plant reproductive success was investigated via controlled visitor-exclusion experiments. Pollinators were expected to be more important for the outcrossing species than for the selfing species, and this was confirmed by the results of the exclusion experiments. In S. caseolaris reproductive success was determined both by pollinator availability and the intensity of flower and fruit predation, while in A. corniculatum it is likely to be resource limited.

Effect of Fasting under Different Temperature Conditions on Nucleic Acid Ratios in the Opossum Shrimp Mysis relicta: a Calibration Approach

2008 ◽  
Vol 34 (3) ◽  
pp. 461-471 ◽  
Author(s):  
Christian Schlechtriem ◽  
Ora E. Johannsson ◽  
Kelly L. Bowen ◽  
Richard W. Smith ◽  
Michael T. Arts
Keyword(s):  
Nucleic Acid ◽  
Mysis Relicta ◽  
Temperature Conditions ◽  
Opossum Shrimp ◽  
Calibration Approach

scholarly journals Risk-adjusted antibiotic consumption in 34 public acute hospitals in Ireland, 2006 to 2014

2016 ◽  
Vol 21 (32) ◽  
Author(s):  
Ajay Oza ◽  
Fionnuala Donohue ◽  
Howard Johnson ◽  
Robert Cunney
Keyword(s):  
Administrative Data ◽  
Risk Adjustment ◽  
Antibiotic Consumption ◽  
Factors Affecting ◽  
Defined Daily Doses ◽  
Acute Hospitals ◽  
Consumption Rates ◽  
Hospital Antibiotic Consumption ◽  
Bed Days ◽  
The Impact

As antibiotic consumption rates between hospitals can vary depending on the characteristics of the patients treated, risk-adjustment that compensates for the patient-based variation is required to assess the impact of any stewardship measures. The aim of this study was to investigate the usefulness of patient-based administrative data variables for adjusting aggregate hospital antibiotic consumption rates. Data on total inpatient antibiotics and six broad subclasses were sourced from 34 acute hospitals from 2006 to 2014. Aggregate annual patient administration data were divided into explanatory variables, including major diagnostic categories, for each hospital. Multivariable regression models were used to identify factors affecting antibiotic consumption. Coefficient of variation of the root mean squared errors (CV-RMSE) for the total antibiotic usage model was very good (11%), however, the value for two of the models was poor (> 30%). The overall inpatient antibiotic consumption increased from 82.5 defined daily doses (DDD)/100 bed-days used in 2006 to 89.2 DDD/100 bed-days used in 2014; the increase was not significant after risk-adjustment. During the same period, consumption of carbapenems increased significantly, while usage of fluoroquinolones decreased. In conclusion, patient-based administrative data variables are useful for adjusting hospital antibiotic consumption rates, although additional variables should also be employed.

Factors affecting the feeding rate of the winkle Littorina littorea

1971 ◽  
Vol 9 (2) ◽  
pp. 138-144 ◽  
Author(s):  
R. C. Newell ◽  
V. I. Pye ◽  
M. Ahsanullah
Keyword(s):  
Feeding Rate ◽  
Littorina Littorea ◽  
Factors Affecting

Further studies on the effects of dietary cottonseed oil on milk-fat secretion in the cow

1968 ◽  
Vol 35 (3) ◽  
pp. 343-352 ◽  
Author(s):  
W. Steele ◽  
J. H. Moore
Keyword(s):  
Fatty Acids ◽  
Milk Fat ◽  
Volatile Fatty Acids ◽  
Octadecenoic Acid ◽  
Cottonseed Oil ◽  
Rumen Fermentation ◽  
Total Volatile ◽  
Feeding Experiments ◽  
Concentrate Mixture ◽  
Low Levels

SummaryThe effects of the isocaloric replacement of part of the dietary concentrate mixture by cottonseed oil on the yield and composition of the milk fat and on the pattern of rumen fermentation was investigated in 2 feeding experiments with a total of 8 cows in mid-lactation. The concentrate mixtures were given with high- or low-roughage diets that supplied 9·1 or 1·8 kg of hay/day.In expt 1 the yield of milk fat was not altered by the addition of 10% cottonseed oil to the concentrate mixtures given either with the high- or with the low-levels of dietary roughage. On the low-roughage treatment, dietary cottonseed oil increased milk yield but reduced the fat content of the milk. The change from the high- to the low-roughage diets containing no cottonseed oil resulted in reductions in the yield and percentage of fat in the milk. In expt 2 the yields of milk and milk fat were similar irrespective of whether the concentrate mixture contained 5 or 10% cottonseed oil.In expt 1 the inclusion of 10% cottonseed oil in the concentrate mixture reduced the yields and percentages of the medium-chain fatty acids (12:0, 14:0 and 16:0) and increased the yields and percentages of the C18 fatty acids in the milk fat. In expt 2, when the concentrate mixture contained 5% cottonseed oil, the yields and percentages of all the fatty acids in the milk fat were similar to the values obtained when the concentrates contained 10% cottonseed oil. For any given concentrate mixture, the change from the high- to the low-roughage treatments in both expts 1 and 2 resulted in increases in the percentage of oleic acid in the milk fat. The highest concentration of trans-octadecenoic acid was observed in the milk fat of the cows when they were given the high-roughage diet with the concentrate mixture containing 10% cottonseed oil.In expt 2 the level of cottonseed oil in the concentrate mixture did not influence the pattern of rumen fermentation as measured by the concentrations of the various volatile fatty acids in the rumen liquor. However, the change from the high- to the low-roughage diets reduced the proportion of acetic and increased the proportions of propionic and n-valeric acids in the total volatile fatty acids in the rumen liquor.

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