scholarly journals Size-related Change in the Visual Resolution of Sunfish (Lepomis spp.)

1994 ◽  
Vol 51 (9) ◽  
pp. 2017-2026 ◽  
Author(s):  
William E. Walton ◽  
Stephen S. Easter Jr. ◽  
Celeste Malinoski ◽  
Nelson G. Hairston Jr.
Keyword(s):  
Body Size ◽  
Standard Length ◽  
Resolving Power ◽  
Pelagic Zone ◽  
Volume Increase ◽  
Fish Size ◽  
Visual Resolution ◽  
Search Volume ◽  
The Mean

Visual resolution of juvenile sunfish (Lepomis spp.) (8–33 mm standard length (SL)), although extremely poor in comparison with the larger individuals (38–160 mm SL) used in previous studies, improves rapidly as they grow. Histologically and behaviorally determined (mean reaction angle) visual angles of fish between 10 and 33 mm SL decrease by approximately 50 and 100 minutes of arc, respectively, and decline non-linearly with increasing fish size. Behaviorally determined visual resolution of juvenile sunfish based on maximum location distance (MLD) is equivalent to that calculated from intercone spacing. The mean reaction angle used in previous studies may have underestimated behavioral visual resolution of larger (> 38 mm SL) sunfish by approximately 30%. Visual volume and search volume increase by nearly three orders of magnitude in sunfish between 8 and 50 mm SL. After sunfish exceed 50 mm SL (when they can safely return to the pelagic zone), visual resolution increases comparatively slowly as body size increases. Our results suggest that the size-related change in behavioral visual resolution in sunfish is influenced by other factors in addition to the growth-related changes in the resolving power of the retina.

Respiratory Exchange and Body Size in the Aldabra Giant Tortoise

1971 ◽  
Vol 55 (3) ◽  
pp. 651-665 ◽  
Author(s):  
G. M. HUGHES ◽  
R. GAYMER ◽  
MARGARET MOORE ◽  
A. J. WOAKES
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Metabolic Rate ◽  
Relative Proportion ◽  
The Body ◽  
O2 Consumption ◽  
Weight Range ◽  
Testudo Hermanni ◽  
The Mean ◽  
Good Agreement

1. The O2 consumption and CO2 release of nine giant tortoises Testudo gigantea (weight range 118 g-35·5 kg) were measured at a temperature of about 25·5°C. Four European tortoises Testudo hermanni (weight range 640 g-2·16 kg) were also used. The mean RQ values obtained were 1·01 for T. gigantea and 0·97 for T. hermanni. These values were not influenced by activity or size. 2. The data was analysed by plotting log/log regression lines relating body weight to O2 consumption. Both maximum and minimum metabolic rates recorded for each individual T. gigantea showed a negative correlation with body weight. For active rates the relation was O2 consumption = 140·8W0·97, whereas for inactive animals O2 consumption = 45·47W0·82. 3. The maximum rates were obtained from animals that were observed to be active in the respirometer and the minimum rates from animals that remained quiet throughout. The scope for activity increased with body size, being 82 ml/kg/h for animals of 100 g and 103 ml/kg/h for 100 kg animals. The corresponding ratio between maximum and minimum rates increases from about 2 to 6 for the same weight range. 4. Values for metabolic rate in T. hermanni seem to be rather lower than in T. gigantea. Analysis of the relative proportion of the shell and other organs indicates that the shell forms about 31% of the body weight in adult T. hermanni but only about 18% in T. gigantea of similar size. The shell is not appreciably heavier in adult T. gigantea (about 20%). 5. Data obtained for inactive animals is in good agreement with results of other workers using lizards and snakes. Previous evidence suggesting that chelonians show no reduction in metabolic rate with increasing size is not considered to conflict with data obtained in the present work.

Questing height of nymphs of the bush tick, Haemaphysalis longicornis, and its closely related species, H. mageshimaensis: correlation with body size of the host

Parasitology ◽  
2004 ◽  
Vol 128 (5) ◽  
pp. 503-509 ◽  
Author(s):  
T. TSUNODA ◽  
S. TATSUZAWA
Keyword(s):  
Body Size ◽  
Sika Deer ◽  
Cervus Nippon ◽  
The Body ◽  
Haemaphysalis Longicornis ◽  
Primary Host ◽  
Closely Related Species ◽  
Glass Tubes ◽  
Vertical Glass ◽  
The Mean

The questing height (i.e. ambush height) of ticks on a plant plays an important role in host selection. To test the hypothesis that the questing height of ticks in a locality had adapted to the body size of the host in that locality, we examined the questing height of nymphs of the ticks, Haemaphysalis longicornis and H. mageshimaensis, at 7 locations in Japan. Sika deer, Cervus nippon, is the primary host of these ticks and there is considerable geographical variation in the body size of sika deer. Multiple regression analysis revealed that the questing height in the field was influenced by the height of the plants and by the body size of deer at a location. However, the questing height of ticks at some locations may have been constrained by the height of the plants and might not be the same as their intrinsic questing height. When ticks were placed in vertical glass tubes in the laboratory, the questing height of ticks from a locality was correlated with the mean body size of deer at that locality. Therefore, the prominent cue determining the questing height of H. longicornis and H. mageshimaensis seems to be the body size of the host deer.

scholarly journals Scaling the feeding mechanism of the largemouth bass (Micropterus salmoides): motor pattern

1995 ◽  
Vol 198 (5) ◽  
pp. 1161-1171 ◽  
Author(s):  
P Wainwright ◽  
B Richard
Keyword(s):  
Body Size ◽  
Largemouth Bass ◽  
Standard Length ◽  
Prey Capture ◽  
Micropterus Salmoides ◽  
Motor Pattern ◽  
Onset Time ◽  
Small Fish ◽  
Scaling Effects ◽  
Emg Signal

We present the first analysis of scaling effects on the motor pattern of a feeding vertebrate. Data are presented for the effects of body size on the pattern of activity in four head muscles during prey capture in the largemouth bass, Micropterus salmoides. Electromyographic (EMG) recordings were made from three expansive-phase muscles (the epaxialis, the sternohyoideus and the levator arcus palatini) and one compressive-phase muscle (the adductor mandibulae), during the capture of small fish prey. Recordings were made of 181 prey-capture events from 19 bass that ranged in size from 83 to 289 mm standard length. We measured seven variables from the myogram of each capture to quantify the temporal pattern of muscle activation, including the duration of activity in each muscle and the onset time of each muscle, relative to the onset of the sternohyoideus muscle. Regressions of the mean value of each variable for the 19 individuals on standard length revealed that only the onset time of the adductor mandibulae changed with fish body size. The increase in onset time of the adductor muscle appears to reflect the longer time taken to open the mouth fully in larger fish. Other research shows that the kinematics of the strike in this species slows significantly with increasing body size. The combined results indicate that the duration of the EMG signal is not directly correlated with the duration of force production in muscles when compared between fish of different sizes. The lack of scaling of burst duration variables suggests that the reduced speeds of prey-capture motion are explained not by changes in the envelope of muscle activity, but rather by the effects of scale on muscle contractile kinetics. These scaling effects may include changes in the relative resistance of the jaw and head structures to movement through water and changes in the intrinsic contractile properties of the muscles of the feeding apparatus.

Metabolic Rate of Female Rats as a Function of Age and Body Size

1956 ◽  
Vol 186 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Max Kleiber ◽  
Arthur H. Smith ◽  
Theodore N. Chernikoff
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Metabolic Rate ◽  
Age Groups ◽  
Female Rats ◽  
Standard Errors ◽  
Normal Female ◽  
Metabolic Rates ◽  
The Mean ◽  
Specific Unit

On the basis of 926 respiration trials, metabolic rates of normal female rats are presented as means of 42 different age groups from birth to 1000 days of age. The means with their standard errors are given for the metabolic rates per rat, per kilogram weight, per unit of the 2/3 power of body weight (surface), and per unit of the 3/4 power of body weight (inter specific unit of metabolic body size). A minimum of 72.6 Cal/kg.3/4 occurs between the ages of 200 and 300 days. An equation with two exponentials predicts the metabolic rate of rats from 77–1000 days of age with a standard deviation between prediction and observation of 2.2% of the mean.

The effect of body size and body condition on the ovulation rate of ewes

1977 ◽  
Vol 24 (3) ◽  
pp. 377-385 ◽  
Author(s):  
M. J. Ducker ◽  
J. S. Boyd
Keyword(s):  
Body Size ◽  
Breeding Season ◽  
Body Condition ◽  
Live Weight ◽  
Ovulation Rate ◽  
Subjective Measure ◽  
Body Dimensions ◽  
The Mean ◽  
Per Se ◽  
Linear Body

SUMMARYBody size was estimated for 255 Greyface ewes using five linear body dimensions. On the basis of this calculated measure combined with a subjective measure of body size 50 small and 50 large ewes were selected for use in the experiment. Precise ovulation data were obtained by endoscopy and this technique allowed the ewes to be mated subsequently.Body size did not affect the mean ovulation rate of the ewes although, at the same level of body condition, the large ewes were 25% heavier than the small ewes. The ovulation rates and the numbers of lambs born were influenced by changes in live weight and body condition. For these reasons live weight per se was not a good indicator of ovulation rate as ewe live weight was a combination of both body size and body condition. At the same live weight small ewes in improving body condition had a significantly higher ovulation rate than large ewes in reducing body condition.The onset of the breeding season of the ewes was not affected by their body size. The mean date of onset of oestrous activity for both large and small ewes was 17 October 1972 at a latitude 55° 52′ N.

Impact of Physician Navigators on productivity indicators in the ED

2017 ◽  
Vol 35 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Alexander K Leung ◽  
Gaurav Puri ◽  
Bingshu E Chen ◽  
Zhenxian Gong ◽  
Eddie Chan ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Patient Volume ◽  
Autoregressive Modelling ◽  
Volume Increase ◽  
Left Without Being Seen ◽  
Before And After ◽  
Physician Time ◽  
The Mean ◽  
Productivity Indicators

ObjectivesWe created Physician Navigators in our ED to help improve emergency physician (EP) productivity. We aimed to quantify the effect of Physician Navigators on measures of EP productivity: patient seen per hour (Pt/hr), and turn-around time (TAT) to discharge. Secondary objectives included examining their impact on measures of ED throughput for non-resuscitative patients: ED length of stay (LOS), door-to-physician time and left-without-being-seen rates (LWBS).MethodsIn this retrospective study, 6845 clinical shifts worked by 20 EPs at a community ED in Newmarket, Canada from 1 January 2012 to 31 March 2015 were evaluated. Using a clustered design, we compared productivity measures between shifts with and without Physician Navigators, by physician. We used a linear mixed model to examine mean changes in Pt/hr and TAT to discharge for EPs who employed Physician Navigators. For secondary objectives, autoregressive modelling was performed to compare ED throughput metrics before and after the implementation of Physician Navigators for non-resuscitative patients.ResultsPatient volumes increased by 20 patients per day (p<0.001). Mean Pt/hr increased by 1.07 patients per hour (0.98 to 1.16, p<0.001). The mean TAT to discharge decreased by 10.6 min (−13.2 to −8.0, p<0.001). After implementation of the Physician Navigator programme, overall mean LOS for non-resuscitative patients decreased by 2.6 min (p=0.007), and mean door-to-physician time decreased by 7.4 min (p<0.001). LBWS rates decreased from 1.13% to 0.63% of daily patient volume (p<0.001).ConclusionDespite an ED volume increase, the use of a Physician Navigator was associated with significant improvements in EP productivity, and significant reductions in ED throughput times.

scholarly journals Age, growth and yield per recruit analysis of the pintado Pseudoplatystoma corruscans (Agassiz, 1829) in the Cuiabá River basin, Pantanal Matogrossense, Brazil

2004 ◽  
Vol 64 (2) ◽  
pp. 257-264 ◽  
Author(s):  
L. A. F. Mateus ◽  
M. Petrere Jr.
Keyword(s):  
Standard Length ◽  
Total Mortality ◽  
Age And Growth ◽  
Growth And Yield ◽  
Dry Period ◽  
Growth Rings ◽  
Pectoral Fins ◽  
The Mean ◽  
Yield Per Recruit ◽  
Species Being

The age and growth of the pintado Pseudoplatystoma corruscans were studied during the period from May 1994 to May 1995. The standard length ranged from 52 to 145 cm and the weight from 1.3 to 41 kg. The biometric relationship between the standard length (Ls) and total length (Ltotal) and between the total weight (Wt) and the standard length (Ls) were obtained for the species, being respectively: Ltotal = 3.296 + 1.069 * Ls and Wt = 0.00624 * Ls3.134.The condition factor calculated monthly suggests the spawning season to be between the months of February and March. The age was estimated by counting growth rings present in the spines of the pectoral fins, and 10 age classes were detected. The mean distance of the last ring until the border of the spine suggests that the period of least growth is between July and September (dry period). Von Bertalaffy's equation describing the growth of the pintado is: Lt = 183 * [1 - exp - 0.085 * (t + 3.274)]. Total mortality was Z = 0.24 year-1 and natural mortality M = 0.20 year-1. As the present level of exploitation, F = Z - M = 0.04 year-1, we conclude that the pintado stock was still underexploited in the Pantanal in the sampled period.

Breed of ewe effects on the utilisation of pasture maintained at two sward heights

1986 ◽  
Vol 1986 ◽  
pp. 78-78
Author(s):  
J M Doney ◽  
A D M Smith ◽  
D A Sim ◽  
I R White
Keyword(s):  
Body Size ◽  
Lolium Perenne ◽  
Accumulation Rate ◽  
Research Station ◽  
Weed Species ◽  
Sward Height ◽  
Experimental Area ◽  
Electric Fence ◽  
Grazing Area ◽  
The Mean

An experiment was carried out at the Glensaugh research station to investigate the effects of breeds of ewe, differing in mature body size on the utilisation of a long-established reseed maintained at sward heights of 3.5 and S.5 cm until weaning.The experimental area, dominated by Lolium perenne (40%), Poa spp (30%) with other grasses (10%) and weed species (20%), was divided into 12 plots each of 0.7 ha. When the mean sward height reached at least 3.5 cm in every plot (13.5.85) they were each stocked with 9 ewes + 15 lambs from one of 3 ewe genotypes (Border Leicester x Blackface, GF; East Friesland x Blackface, EFX; Cheviot x Shetland, SHX) in two replicates. All lambs were sired by Suffolk rams.Mean sward height, herbage mass and estimated herbage accumulation rate were measured weekly and ewes and lambs were weighed weekly. Sward heights were maintained on each plot by movement of an electric fence to vary the grazing area. The area behind the fence was maintained at an equal sward height by non-experimental ewes and lambs to permit movement in any direction. The lambs were approximately 6 weeks old at the beginning of the trial and were weaned after 13 weeks on the plots.

scholarly journals Aspects of the ecology of the Asian tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934 in yellowfish in the Vaal Dam, South Africa

2005 ◽  
Vol 72 (3) ◽  
Author(s):  
A. Bertasso ◽  
A. Avenant-Oldewage
Keyword(s):  
Surface Water Quality ◽  
Seasonal Patterns ◽  
Fish Size ◽  
Mean Intensity ◽  
Low Intensity ◽  
Four Seasons ◽  
Vaal Dam ◽  
Bothriocephalus Acheilognathi ◽  
The Mean ◽  
Ecological Parameters

Seasonal surveys were conducted at the Vaal Dam between April 2000 and January 2001. Twenty smallmouth yellowfish (Labeobarbus aeneus) and 20 largemouth yellowfish (Labeobarbus kimberleyensis) were collected with the aid of gill nets. Surface water quality variables were included. The cestodes were identified as either Bothriocephalus acheilognathi Yamaguti, 1934 or "other cestode spp.". The majority (99.8 %) of the cestodes found in both yellowfish species were identified as B. acheilognathi (Asian tapeworm). The prevalence, mean intensity and abundance of B. acheilognathi in both yellowfish species were calculated. Ecological parameters including species specificity, seasonality, gender specificity and relationships between fish size and the Asian tapeworm prevalence were also included. In this study, B. acheilognathi preferred L. kimberleyensis over L. aeneus although a low intensity was observed in smallmouth yellowfish. Furthermore, the infection (in terms of prevalence, abundance and mean intensity) in largemouth yellowfish was markedly higher. Seasonal patterns observed in the Asian tapeworm's infection of smallmouth yellowfish are attributed to breeding and subsequent feeding patterns of this fish species with relatively high infections recorded in winter and spring. For L. kimberleyensis no explanation can be given regarding the seasonal patterns observed for the mean intensity and abundance of B. acheilognathi. The maximum and minimum mean intensity and abundance values in largemouth yellowfish were recorded in autumn and spring, respectively. In addition, the prevalence of B. acheilognathi was consistently high in all four seasons.

The distribution of phytoplankton along trophic gradients and its mediation by available light in the pelagic zone of large eutrophic lakes

2012 ◽  
Vol 69 (12) ◽  
pp. 1935-1946 ◽  
Author(s):  
Min Zhang ◽  
Yang Yu ◽  
Zhen Yang ◽  
Xiaoli Shi ◽  
Fanxiang Kong
Keyword(s):  
Lake Management ◽  
Pelagic Zone ◽  
Light Limitation ◽  
Eutrophic Lakes ◽  
Large Lakes ◽  
Factors Affecting ◽  
Key Species ◽  
Principal Factors ◽  
The Mean ◽  
Taxonomic Groups

We describe the pattern and the principal factors affecting the phytoplankton biomass–nutrient relationship in the pelagic zone of large lakes. The results showed that the phytoplankton abundance and biomass of Cyanophyta, Cryptophyta, and Pyrrophyta were significantly correlated with trophic states. The total phosphorus (TP)–biomass relationship curves showed that the increment of biomass with TP is weak at high TP levels. The decrease in biomass at the high end of the curves might be a synthesis of the pattern of responses of the major taxonomic groups (except cyanobacteria) to environmental variables. Light limitation might be one of the important factors causing the decrease in the TP–biomass curve at high TP concentrations. If the mean underwater available light is lower than ∼250 µmol photons·m–2·s–1, clear-water species decline and cyanobacteria become dominant. The responses to available light of these key species play a central role in modulating the biomass–nutrient relationship. Our results contribute to the understanding of this relationship in the pelagic zone of large eutrophic lakes and have important practical implications for lake management.

Sign in / Sign up

Export Citation Format

Share Document