Estimating growth of the Spiny Lobsters Panulirus cygnus, P.argus and P. ornatus

1992 ◽  
Vol 43 (5) ◽  
pp. 1177 ◽  
Author(s):  
BF Phillips ◽  
MJ Palmer ◽  
R Cruz ◽  
JT Trendall
Keyword(s):  
Growth Rates ◽  
Spiny Lobster ◽  
Field Studies ◽  
High Variability ◽  
Tropical Species ◽  
Random Coefficient Models ◽  
Spiny Lobsters ◽  
The Mean ◽  
Approximate Confidence Intervals ◽  
Panulirus Cygnus

Growth in three species of spiny lobster-Panulirus cygnus in Western Australia, P. argus in Cuba, and P. ornatus in Torres Strait, Australia-was modelled by using nonlinear random-coefficient models. Approximate confidence intervals about the mean growth curve for carapace length, to include 95% of the population at any age, have been estimated for these models. For both P. ornatus and P. cygnus, similar estimates of growth rate were obtained from both laboratory and field studies. Growth of the two tropical species, P. ornatus and P. argus, was much faster than that of the temperate species P. cygnus. All three species showed high variability in the growth rates of individuals. Microtagging of first-moult post-puerulus juveniles of P. cygnus with 1 mm long × 0.25 mm stainless-steel tags provides the first published field data on the growth of spiny lobsters from the beginning of the benthic period. These data suggest that tagging or handling can decrease the growth rates of spiny lobsters.

scholarly journals Ultrasound Surveillance of Ectatic Abdominal Aortas

2008 ◽  
Vol 90 (6) ◽  
pp. 477-482 ◽  
Author(s):  
S Devaraj ◽  
SR Dodds
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Screening Programme ◽  
T Test ◽  
Aortic Aneurysms ◽  
Aortic Diameter ◽  
Ultrasound Screening ◽  
The Mean ◽  
Clinically Significant

INTRODUCTION Some studies have considered abdominal aortas of 2.6–2.9 cm diameter (ectatic aortas) at age 65 years as being abnormal and have recommended surveillance, whereas others have considered these normal and surveillance unnecessary. It is, therefore, not clear how to manage patients with an initial aortic diameter between 2.6–2.9 cm detected at screening. The aim of this study was to evaluate growth rates of ectatic aortas detected on initial ultrasound screening to determine if any developed into clinically significant abdominal aortic aneurysms (AAAs; > 5.0 cm) and clarify the appropriate surveillance intervals for these patients. PATIENTS AND METHODS Data were obtained from a prospective AAA screening programme which commenced in 1992. The group of patients with initial aortic diameters of 2.6–2.9 cm with a minimum of 1-year follow-up were included in this study (Group 2). This was further divided into two subgroups (Groups 3a and 3b) based on a minimum follow-up interval obtained from outcome analysis. Mean growth rate was calculated as change in aortic diameter with time. The comparison of growth rates in Groups 3a and 3b was performed using the t-test. The number and proportion of AAAs that expanded to ≥ 3.0 cm and ≥ 5.0 cm in diameter were also calculated. RESULTS Out of 999 patients with AAA ≥ 2.6 cm with minimum 1-year follow-up, 358 (36%) were classified as ectatic aortas (2.6–2.9 cm) at initial ultrasound screening with the mean growth rate of 1.69 mm/year (95% CI, 1.56–1.82 mm/year) with a mean follow-up of 5.4 years. Of these 358 ectatic aortas, 314 (88%) expanded into ≥ 3.0 cm, 45 (13%) expanded to ≥ 5.0 cm and only 8 (2%) expanded to ≥ 5.5 cm over a mean follow-up of 5.4 years (range, 1–14 years). No ectatic aortas expanded to ≥ 5.0 cm within the first 4 years of surveillance. Therefore, the minimum follow-up interval was set at 4 years and this threshold was then used for further analysis. The mean growth rate in Group 3a (< 5.0 cm at last scan) was 1.33 mm/year (95% CI, 1.23–1.44 mm/year) with a mean follow-up of 7 years compared to Group 3b (≥ 5.0 cm at last scan) with the mean growth rate of 3.33 mm/year (95% CI 3.05–3.61 mm/year) and a mean follow-up of 8 years. The comparison of mean growth rates between Groups 3a and 3b is statistically significant (t-test; T = 13.00; P < 0.001). CONCLUSIONS One-third of patients undergoing AAA screening will have ectatic aortas (2.6–2.9 cm) and at least 13% of these will expand to a size of ≥ 5.0 cm over a follow-up of 4–14 years. A threshold diameter of 2.6 cm for defining AAAs in a screening programme is recommended and ectatic aortas detected at age 65 years can be re-screened at 4 years after the initial scan. A statistically significant difference was found in the growth rates of ectatic aortas with minimum 4 years follow-up, expanding to ≥ 5.0 cm compared to those less than 5.0 cm at last surveillance scan. Further studies are required to test the hypothesis of whether growth rate over the first 4 years of surveillance will identify those who are most likely to expand to a clinically significant size (> 5.0 cm).

Respiratory Periodicity and Electroencephalogram Arousals During Sleep in Older Adults

2007 ◽  
Vol 8 (4) ◽  
pp. 249-260 ◽  
Author(s):  
Barbara Waag Carlson ◽  
Virginia J. Neelon ◽  
John R. Carlson ◽  
Marilyn Hartman ◽  
Sunil Dogra
Keyword(s):  
Older Adults ◽  
Exploratory Study ◽  
High Variability ◽  
Arterial Oxygenation ◽  
Type B ◽  
Breathing Patterns ◽  
The Mean ◽  
Relationship Of ◽  
The Relationship ◽  
Electroencephalogram Eeg

The aim of this exploratory study was to examine the relationship of electroencephalogram (EEG) arousals to breathing patterns and the relationship of both arousals and breathing patterns to arterial oxygenation during sleep in older adults. Five older adults were monitored using standard polysomnography. Records were divided into 5-min segments and breathing patterns identified based on the level of respiratory periodicity and the variability in the frequency of breathing cycles. Standard criteria were used to determine sleep states and occurrence of EEG arousals. High respiratory periodicity was seen in 23% of the segments, whereas 24% had low respiratory periodicity with minimal variability in the frequency of breathing (Type A low respiratory periodicity) and 53% had low respiratory periodicity with high variability in the frequency of breathing (Type B low respiratory periodicity). Nearly all (97%) segments with high respiratory periodicity had EEG arousals, whereas fewer segments (33%) with low respiratory periodicity had arousals, regardless of the stage of sleep. Desaturations occurred more often in segments with high respiratory periodicity, F (2,4) = 57.3, p < .001, but overall, the mean SaO2 of segments with high respiratory periodicity did not differ from levels seen in segments with low respiratory periodicity, F( 2,4) = 0.77, ns. Our findings suggest that high respiratory periodicity is a common feature of EEG arousals and, in older adults, may be important for maintaining oxygen levels during desaturations during sleep.

scholarly journals Effects of Matric and Osmotic Priming Treatments on Broccoli Seed Germination

1996 ◽  
Vol 121 (3) ◽  
pp. 423-429 ◽  
Author(s):  
Lewis W. Jett ◽  
Gregory E. Welbaum ◽  
Ronald D. Morse
Keyword(s):  
Polyethylene Glycol ◽  
Seed Germination ◽  
Root Growth ◽  
Growth Rates ◽  
Germination Rate ◽  
Membrane Integrity ◽  
Seed Vigor ◽  
Radicle Emergence ◽  
The Mean ◽  
Peg 8000

Priming, a controlled-hydration treatment followed by redrying, improves the germination and emergence of seeds from many species. We compared osmotic and matric priming to determine which was the most effective treatment for improving broccoli seed germination and to gain a greater understanding of how seed vigor is enhanced by priming. Broccoli (Brassica oleracea L. var. italica) seeds were osmotically primed in polyethylene glycol (PEG 8000) at -1.1 MPa or matrically primed in a ratio of 1.0 g seed:0.8 g synthetic calcium silicate (Micro-Cel E):1.8 ml water at -1.2 MPa. In the laboratory, germination rates and root lengths were recorded from 5 to 42C and 10 to 35C, respectively. Broccoli seeds germinated poorly at >35C. Root growth after germination was more sensitive to temperatures >30C and <15C than radicle emergence. Matric and osmotic priming increased germination rate in the laboratory, greenhouse, and field. However, matric priming had a greater effect on germination and root growth rates from 15 to 30C. Neither priming treatment affected minimum or maximum germination or root growth temperatures. Both priming treatments decreased the mean thermal time for germination by >35%. The greater germination performance of matrically primed seeds was most likely the result of increased oxygen availability during priming, increased seed Ca content, or improved membrane integrity.

scholarly journals Implementation of a provincial acute stroke pathway and its impact on access to advanced stroke care in Saskatchewan

2021 ◽  
Vol 10 (3) ◽  
pp. e001214
Author(s):  
Jessalyn K Holodinsky ◽  
Vivian N Onaemo ◽  
Ruth Whelan ◽  
Gary Hunter ◽  
Brett R Graham ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Control Charts ◽  
Systems Of Care ◽  
Stroke Care ◽  
High Variability ◽  
Weighted Mean ◽  
Improvement Project ◽  
Outcome Severity ◽  
The Mean ◽  
Over Time

BackgroundFor ischaemic stroke, outcome severity is heavily time dependent. Systems of care need to be in place to ensure that patients with stroke are treated quickly and appropriately across entire health regions. Prior to this study, the province of Saskatchewan, Canada did not have a provincial stroke strategy in place.MethodsA quality improvement project was undertaken to create and evaluate a provincial stroke strategy. The Saskatchewan Acute Stroke Pathway was created using a multidisciplinary team of experts, piloted at five stroke centres and then implemented provincially. The number of stroke alerts, door-to-imaging, door-to-needle, door-to-groin puncture times and treatment rates were collected at all centres. Improvements over time were analysed using run charts and individuals control charts.ResultsThe number of stroke alerts province-wide trended upwards in the last 6 months of the study. There were no clear trends or shifts in the proportion of stroke alerts treated with alteplase or endovascular therapy. Across the province, the weighted mean door-to-imaging time decreased from 21 to 15 min, the weighted mean door-to-needle time decreased from 62 to 47 min and the mean door-to-groin puncture time decreased from 83 to 70 min. There was high variability in the degree of improvement from centre to centre.ConclusionsThe implementation of a province wide acute stroke pathway has led to improvement in stroke care on a provincial basis. Further work addressing intercentre variability is ongoing.

Improved approximate confidence intervals for the mean of a log-normal random variable

2002 ◽  
Vol 21 (10) ◽  
pp. 1443-1459 ◽  
Author(s):  
Douglas J. Taylor ◽  
Lawrence L. Kupper ◽  
Keith E. Muller
Keyword(s):  
Confidence Intervals ◽  
Random Variable ◽  
Normal Random Variable ◽  
The Mean ◽  
Approximate Confidence Intervals ◽  
Log Normal

Do abiotic mechanisms determine interannual variability in length-at-age of juvenile Arcto-Norwegian cod?

2002 ◽  
Vol 59 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Geir Ottersen ◽  
Kristin Helle ◽  
Bjarte Bogstad
Keyword(s):  
Growth Rates ◽  
Gadus Morhua ◽  
Barents Sea ◽  
Water Masses ◽  
Inverse Relation ◽  
Lower Growth ◽  
Density Dependent ◽  
The Barents Sea ◽  
The Mean ◽  
Dependent Growth

For the large Arcto-Norwegian stock of cod (Gadus morhua L.) in the Barents Sea, year-to-year variability in growth is well documented. Here three hypotheses for the observed inverse relation between abundance and the mean length-at-age of juveniles (ages 1–4) are suggested and evaluated. Based on comprehensive data, we conclude that year-to-year differences in length-at-age are mainly determined by density-independent mechanisms during the pelagic first half year of the fishes' life. Enhanced inflow from the southwest leads to an abundant cohort at the 0-group stage being distributed farther east into colder water masses, causing lower postsettlement growth rates. We can not reject density-dependent growth effects related to variability in food rations, but our data do not suggest this to be the main mechanism. Another hypothesis suggests that lower growth rates during periods of high abundance are a result of density-dependent mechanisms causing the geographic range of juveniles to extend eastwards into colder water masses. This is rejected mainly because year-to-year differences in mean length are established by age 2, which is too early for movements over large distances.

Responses of olfactory receptor cells of spiny lobsters to binary mixtures. II. Pattern mixture interactions

1991 ◽  
Vol 66 (1) ◽  
pp. 131-139 ◽  
Author(s):  
C. D. Derby ◽  
M. N. Girardot ◽  
P. C. Daniel
Keyword(s):  
Binary Mixtures ◽  
Olfactory Receptor ◽  
Neural Coding ◽  
Spiny Lobster ◽  
Neuronal Population ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Spiny Lobsters ◽  
Mixture Interactions

1. The effect of mixture interactions in individual olfactory receptor cells of the spiny lobster on neural coding of odorant quality of binary mixtures and their components is examined in this paper. Extracellular responses of 98 olfactory receptor cells in the antennules of spiny lobsters to seven compounds [adenosine-5'-monophosphate (AMP), betaine (Bet), L-cysteine (Cys), L-glutamate (Glu), ammonium chloride (NH4), DL-succinate (Suc), taurine (Tau)] and their binary mixtures were recorded, and mixture interactions in individual olfactory receptor cells were identified. 2. Coding of odorant quality was evaluated by examining across neuron patterns (ANPs)--the relative response magnitudes across neuronal populations. ANPs are a feature of the neuronal population response and are a possible concentration-independent code of odorant quality in this system, as indicated by previous studies and present results. 3. For most binary mixtures the diversity of types and degrees of mixture interactions across the individual cells of a population of cells resulted in ANPs for each mixture to be different from the ANPs for the components of the mixture and different from the ANP predicted for the mixture from the responses to the components (Figs. 2–10). These effects are called pattern mixture interactions (PMIs). PMIs occurred for most binary mixtures, even those that did not produce statistically significant intensity mixture interactions (IMIs) for this same population of cells. 4. The results suggest that PMIs can influence coding of stimulus quality, in some cases by causing an improvement of the contrast between the quality of mixtures and some of their components.

Inhibitory Glutamate Receptor Channels in Cultured Lobster Stomatogastric Neurons

1998 ◽  
Vol 79 (6) ◽  
pp. 3189-3196 ◽  
Author(s):  
Thomas A. Cleland ◽  
Allen I. Selverston
Keyword(s):  
Glutamate Receptor ◽  
Gaba Receptor ◽  
Kynurenic Acid ◽  
Channel Blocker ◽  
Spiny Lobster ◽  
Hill Coefficient ◽  
Chloride Channel Blocker ◽  
The Mean ◽  
Mean Variance ◽  
Muscular Tissues

Cleland, Thomas A. and Allen I. Selverston. Inhibitory glutamate receptor channels in cultured lobster stomatogastric neurons. J. Neurophysiol. 79: 3189–3196, 1998. Inhibitory glutamate receptor channels (IGluRs) are ligand-gated ionotropic receptors related to ionotropic γ-aminobutyric acid (GABA) and glycine receptors and expressed in neural and muscular tissues. In the crustacean stomatogastric ganglion (STG), IGluRs mediate recurrent synaptic inhibition central to the rhythmogenic capabilities of its embedded neural circuits. IGluRs expressed in cultured spiny lobster STG neurons exhibited an EC50 of 1.2 mM and a Hill coefficient of 1.4. They were neither cross-activated nor cross-desensitized by GABA, although a distinct GABA-gated chloride current was observed. Glycine did not evoke any current from STG neurons. The IGluR was weakly blocked by the chloride channel blocker furosemide and the excitatory glutamate receptor antagonist6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), but was not inhibited by bicuculline methiodide, strychnine, kynurenic acid,γ-d-glutamylglycine, or aspartate. Outside-out patch-clamp recordings were analyzed using the mean-variance histogram technique. Under excised-patch conditions, the receptor exhibited only a single open state with an estimated unitary conductance of 80 ± 8.6 (SD) pS. The distinct GABA receptor also displayed a single open state with a conductance of 72 ± 10 pS.

scholarly journals Host specificity of insect herbivores in tropical forests

2005 ◽  
Vol 272 (1568) ◽  
pp. 1083-1090 ◽  
Author(s):  
Vojtech Novotny ◽  
Yves Basset
Keyword(s):  
Host Specificity ◽  
Tropical Forests ◽  
Plant Species ◽  
Field Studies ◽  
Tropical Species ◽  
Distribution Data ◽  
Insect Herbivores ◽  
Leaf Miners ◽  
Experimental Conditions ◽  
Plant Phylogeny

Studies of host specificity in tropical insect herbivores are evolving from a focus on insect distribution data obtained by canopy fogging and other mass collecting methods, to a focus on obtaining data on insect rearing and experimentally verified feeding patterns. We review this transition and identify persisting methodological problems. Replicated quantitative surveys of plant–herbivore food webs, based on sampling efforts of an order of magnitude greater than is customary at present, may be cost-effectively achieved by small research teams supported by local assistants. Survey designs that separate historical and ecological determinants of host specificity by studying herbivores feeding on the same plant species exposed to different environmental or experimental conditions are rare. Further, we advocate the use of host‐specificity measures based on plant phylogeny. Existing data suggest that a minority of species in herbivore communities feed on a single plant species when alternative congeneric hosts are available. Thus, host plant range limits tend to coincide with those of plant genera, rather than species or suprageneric taxa. Host specificity among tropical herbivore guilds decreases in the sequence: granivores>leaf-miners>fructivores>leaf-chewers=sap-suckers>xylophages>root-feeders, thus paralleling patterns observed in temperate forests. Differences in host specificity between temperate and tropical forests are difficult to assess since data on tropical herbivores originate from recent field studies, whereas their temperate counterparts derive from regional host species lists, assembled over many years. No major increase in host specificity from temperate to tropical communities is evident. This conclusion, together with the recent downward revisions of extremely high estimates of tropical species richness, suggest that tropical ecosystems may not be as biodiverse as previously thought.

Serotonin Transduction Cascades Mediate Variable Changes in Pyloric Network Cycle Frequency in Response to the Same Modulatory Challenge

2008 ◽  
Vol 99 (6) ◽  
pp. 2844-2863 ◽  
Author(s):  
Nadja Spitzer ◽  
Gennady Cymbalyuk ◽  
Hongmei Zhang ◽  
Donald H. Edwards ◽  
Deborah J. Baro
Keyword(s):  
Steady State ◽  
Spiny Lobster ◽  
Cycle Frequency ◽  
Panulirus Interruptus ◽  
Response System ◽  
Pyloric Network ◽  
Bath Application ◽  
The Mean ◽  
Circuit Output ◽  
Sustained Increase

A fundamental question in systems biology addresses the issue of how flexibility is built into modulatory networks such that they can produce context-dependent responses. Here we examine flexibility in the serotonin (5-HT) response system that modulates the cycle frequency (cf) of a rhythmic motor output. We found that depending on the preparation, the same 5-min bath application of 5-HT to the pyloric network of the California spiny lobster, Panulirus interruptus, could produce a significant increase, decrease, or no change in steady-state cf relative to baseline. Interestingly, the mean circuit output was not significantly different among preparations prior to 5-HT application. We developed pharmacological tools to examine the preparation-to-preparation variability in the components of the 5-HT response system. We found that the 5-HT response system consisted of at least three separable components: a 5-HT2βPan-like component mediated a rapid decrease followed by a sustained increase in cf; a 5-HT1αPan-like component produced a small and usually gradual increase in cf; at least one other component associated with an unknown receptor mediated a sustained decrease in cf. The magnitude of the change in cf produced by each component was highly variable, so that when summed they could produce either a net increase, decrease, or no change in cf depending on the preparation. Overall, our research demonstrates that the balance of opposing components of the 5-HT response system determines the direction and magnitude of 5-HT–induced change in steady-state cf relative to baseline.

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