Diving beetles (Dytiscidae) as predators of mosquito larvae (Culicidae) in field experiments and in laboratory tests of prey preference

2003 ◽  
Vol 93 (3) ◽  
pp. 219-226 ◽  
Author(s):  
E. Lundkvist ◽  
J. Landin ◽  
M. Jackson ◽  
C. Svensson
Keyword(s):  
Body Length ◽  
Negative Correlation ◽  
Laboratory Tests ◽  
Field Experiments ◽  
Mosquito Larvae ◽  
Natural Control ◽  
Large Numbers ◽  
Diving Beetles ◽  
The Mean ◽  
Artificial Ponds

AbstractField experiments were performed in artificial ponds to evaluate how the density of predatory diving beetles (Dytiscidae) would affect the population levels of mosquito larvae (Culicidae). Mosquitoes colonizing the ponds were predominantly species of the genus Culex. In 2000, most of the dytiscids colonizing the ponds were small (Hydroporus spp.), and these predators had no impact on the size of larval mosquito populations, not even in ponds with added dytiscids. In 2001, larger beetles (Ilybius, Rhantus, and Agabus spp.) were more common, and there were significantly fewer mosquito larvae in ponds with the highest numbers of dytiscids. There was a negative correlation between numbers of diving beetles in the ponds and the mean body length of mosquito larvae. In neither year could dytiscid densities be maintained above a certain level owing to emigration. In laboratory tests, there were marked differences between three common dytiscid species in regard to preferences for Daphnia and Culex species as prey: Colymbetes paykulli Erichson chose mosquito larvae more often, whereas both Ilybius ater (De Geer) and I. fuliginosus (Fabricius) preferred Daphnia spp. All of the tested dytiscids consumed large numbers of prey. Since some dytiscid species can efficiently decrease populations of mosquito larvae, they are probably important in the natural control of these dipterans.

scholarly journals Scavenging behaviour by Ergalatax contractus (Gastropoda: Muricidae) and interactions with Nassarius nodifer (Gastropoda: Nassariidae) in the Cape d'Aguilar Marine Reserve, Hong Kong

2006 ◽  
Vol 86 (1) ◽  
pp. 141-152 ◽  
Author(s):  
Brian Morton
Keyword(s):  
Hong Kong ◽  
Field Experiments ◽  
Marine Reserve ◽  
Flowing Water ◽  
Large Numbers ◽  
Baited Traps ◽  
Behavioural Characteristics ◽  
Shallow Subtidal ◽  
The Mean ◽  
Mean Time

Aspects of the feeding behaviour of Ergalatax contractus (Muricidae) were studied. Field experiments demonstrated that large numbers of individuals of this species, comprising ∼90% of a suite of gastropod scavengers, were attracted to baited traps in the subtidal sands of Lobster Bay, Cape d'Aguilar Marine Reserve, Hong Kong. Laboratory experiments identified the effective chemo-detection distances of E. contractus as 60 cm in still and >80 cm in flowing water, respectively. The average times to arrival at bait in still and flowing water were 92.3 and 69.0 min, respectively, but were significantly less for individuals experiencing a longer period of starvation. The mean time taken for E. contractus to consume a meal was 70.6 min.Comparisons were made between Ergalatax contractus and Nassarius nodifer, representative of a suite of sympatric scavenging nassariids in Lobster Bay. The nassariid arrived significantly faster at bait in both still (30.2 min) and flowing water (20.8 min) than E. contractus and fed faster (25.7 min), as is typical of representatives of the Nassariidae. Although the two species partition carrion resources temporally, manipulation experiments provided evidence for inter-specific competition between them. That is, although E. contractus possesses the morphological and behavioural characteristics of a predator, its opportunistic scavenging abilities have led to its success and numerical superiority on the shallow subtidal sands of Lobster Bay. The dominance of E. contractus in Lobster Bay, and elsewhere in Hong Kong, is unusual. Here, the normally predatory E. contractus, far outnumbers all other scavengers, possibly because of an enhanced, largely allochthonous, supply of food which it is able to exploit by virtue of its previously identified opportunistic habit of scavenging the leftovers of other predators. The presence of inter-specific competition between E. contractus and a sympatric suite of nassariids enhances, not impedes, carrion exploitation.

Platelet Suruival and Function in Rats with Enhanced Thrombotic Tendency

1985 ◽  
Vol 54 (04) ◽  
pp. 739-743 ◽  
Author(s):  
Federica Delaini ◽  
Elisabetta Dejana ◽  
Ine Reyers ◽  
Elisa Vicenzi ◽  
Germana De Bellis Vitti ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Nephrotic Syndrome ◽  
Platelet Function ◽  
Laboratory Tests ◽  
Thrombus Formation ◽  
The Other ◽  
Mean Survival Time ◽  
The Mean ◽  
And Function ◽  
Thrombotic Tendency

SummaryWe have investigated the relevance of some laboratory tests of platelet function in predicting conditions of thrombotic tendency. For this purpose, we studied platelet survival, platelet aggregation in response to different stimuli, TxB2 and 6-keto-PGFlα production in serum of rats bearing a nephrotic syndrome induced by adriamycin. These animals show a heavy predisposition to the development of both arterial and venous thrombosis. The mean survival time was normal in nephrotic rats in comparison to controls. As to aggregation tests, a lower aggregating response was found in ADR-treated rats using ADP or collagen as stimulating agents. With arachidonic acid (AA) we observed similar aggregating responses at lower A A concentrations, whereas at higher AA concentrations a significantly lower response was found in nephrotic rats, despite their higher TxB2 production. Also TxB2 and 6-keto-PGFlα levels in serum of nephrotic rats were significantly higher than in controls. No consistent differences were found in PGI2-activity generated by vessels of control or nephrotic rats.These data show that platelet function may appear normal or even impaired in rats with a markedly increased thrombotic tendency. On the other hand, the significance of high TxB2 levels in connection with mechanisms leading to thrombus formation remains a controversial issue.

RELATIONSHIP BETWEEN CARDIOVASCULAR DISEASES AND ANATOMOSIS OF ARTERIOVENOUS FISTULAR IN PATIENTS WITH REGULARLY HEMODIALYSIS

2017 ◽  
pp. 88-92
Author(s):  
Van Hien Pham ◽  
Huu Vu Quang Nguyen ◽  
Tam Vo
Keyword(s):  
Heart Failure ◽  
Blood Pressure ◽  
Renal Failure ◽  
Chronic Renal Failure ◽  
Cardiovascular Diseases ◽  
Systolic Blood Pressure ◽  
Diastolic Blood Pressure ◽  
Negative Correlation ◽  
Mean Value ◽  
The Mean

Background: Cardiovascular diseases are the leading cause of death in patients with chronic renal failure. When a patient undergoes dialysis, making AVF or AVG causes cardiovascular events. Understanding the relationship between complications: hypertension, heart failure, AVF or AVG (formation time, position, diameter) helps us monitor, detect, prevent and treatment of complications to limit the risk of death in patients with dialysis. Objective: Relationship between cardiovascular diseases and anatomosis of arteriovenous fistular in patients with regularly hemodialysis at Cho Ray Hospital. Methods: A cross-sectional study was conducted at Cho Ray Hospital from 2015 to 2016. The survey some cardiovascular diseases are done by clinical examination, tests for diagnostic imaging such as X-ray, electrocardiogram and echocardiogram: heart and diameter of anastomosis AVF, AVG. Results: The study population included 303 patients with chronic renal failure who were dialysis. Of which, patients aged 25-45 accounted for the highest proportion (43.9%). The proportion of male and female patients was similar (48.5% and 51.5% respectively). The mean value of systolic blood pressure on patients made AVF, AVG less than 12 months is higher than patients made AVF, AVG over 12 months, and there is negative correlation (r = -0.43) between AVF, AVG and systolic blood pressure (p <0.05). The mean value of diastolic blood pressure on patients made AVF, AVG less than 12 months is lower than patients made AVF, AVG over 12 months, and and there is positive correlation (r = -0.43) between AVF, AVG and diastolic blood pressure (p <0.05) (p <0.05). The prevalence of patients with heart failure made AVF, AVG over 12 months is higher than that of the under 12 months group, there is a negative correlation (r = - 0.43) between AVF, AVG diameter and EF index (p <0.05). Conclusion: It is important to note the diameter of anastomosis AVF, AVG in patients with chronic renal failure dialysis to limit cardiovascular complications, especially heart failure. Key words: Chronic kidney disease, hemodialysis.

scholarly journals P170 The validity and utility of the SLE-key® rule-out serological test when applied in a selected cohort of patients with SLE and other connective tissue diseases

Rheumatology ◽  
2021 ◽  
Vol 60 (Supplement_1) ◽  
Author(s):  
Sheilla Achieng ◽  
John A Reynolds ◽  
Ian N Bruce ◽  
Marwan Bukhari
Keyword(s):  
Linear Regression ◽  
Connective Tissue ◽  
Connective Tissue Disease ◽  
Negative Correlation ◽  
Connective Tissue Diseases ◽  
Inflammatory Myositis ◽  
The Mean ◽  
Negative Rule ◽  
Spearman’S Correlation ◽  
Rule Out

Abstract Background/Aims  We aimed to establish the validity of the SLE-key® rule-out test and analyse its utility in distinguishing systemic lupus erythematosus (SLE) from other autoimmune rheumatic connective tissue diseases. Methods  We used data from the Lupus Extended Autoimmune Phenotype (LEAP) study, which included a representative cross-sectional sample of patients with a variety of rheumatic connective tissue diseases, including SLE, mixed connective tissue disease (MCTD), inflammatory myositis, systemic sclerosis, primary Sjögren’s syndrome and undifferentiated connective tissue disease (UCTD). The modified 1997 ACR criteria were used to classify patients with SLE. Banked serum samples were sent to Immune-Array’s CLIA- certified laboratory Veracis (Richmond, VA) for testing. Patients were assigned test scores between 0 and 1 where a score of 0 was considered a negative rule-out test (i.e. SLE cannot be excluded) whilst a score of 1 was assigned for a positive rule-out test (i.e. SLE excluded). Performance measures were used to assess the test’s validity and measures of association determined using linear regression and Spearman’s correlation. Results  Our study included a total of 155 patients of whom 66 had SLE. The mean age in the SLE group was 44.2 years (SD 13.04). 146 patients (94.1%) were female. 84 (54.2%) patients from the entire cohort had ACR SLE scores of ≤ 3 whilst 71 (45.8%) had ACR SLE scores ≥ 4. The mean ACR SLE total score for the SLE patients was 4.85 (SD 1.67), ranging from 2 to 8, with mean disease duration of 12.9 years. The Sensitivity of the SLE-Key® Rule-Out test in diagnosing SLE from other connective tissue diseases was 54.5%, specificity was 44.9%, PPV 42.4% and NPV 57.1 %. 45% of the SLE patients had a positive rule-out test. SLE could not be ruled out in 73% of the MCTD patients whilst 51% of the UCTD patients had a positive Rule-Out test and &gt;85% of the inflammatory myositis patients had a negative rule-out test. ROC analysis generated an AUC of 0.525 illustrating weak class separation capacity. Linear regression established a negative correlation between the SLE-key Rule-Out score and ACR SLE total scores. Spearman’s correlation was run to determine the relationship between ACR SLE total scores and SLE-key rule-out score and showed very weak negative correlation (rs = -0.0815, n = 155, p = 0.313). Conclusion  Our findings demonstrate that when applied in clinical practice in a rheumatology CTD clinic setting, the SLE-key® rule-out test does not accurately distinguish SLE from other CTDs. The development of a robust test that could achieve this would be pivotal. It is however important to highlight that the test was designed to distinguish healthy subjects from SLE patients and not for the purpose of differentiating SLE from other connective tissue diseases. Disclosure  S. Achieng: None. J.A. Reynolds: None. I.N. Bruce: Other; I.N.B is a National Institute for Health Research (NIHR) Senior Investigator and is funded by the NIHR Manchester Biomedical Research Centre. M. Bukhari: None.

scholarly journals Combining Process Modelling and LAI Observations to Diagnose Winter Wheat Nitrogen Status and Forecast Yield

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 314
Author(s):  
Andrew Revill ◽  
Vasileios Myrgiotis ◽  
Anna Florence ◽  
Stephen Hoad ◽  
Robert Rees ◽  
...  
Keyword(s):  
Field Experiments ◽  
Process Models ◽  
Agricultural Technologies ◽  
N Application ◽  
Area Index ◽  
Complex Process ◽  
C Cycle ◽  
The Mean ◽  
Leaf N Content ◽  
Leaf N

Climate, nitrogen (N) and leaf area index (LAI) are key determinants of crop yield. N additions can enhance yield but must be managed efficiently to reduce pollution. Complex process models estimate N status by simulating soil-crop N interactions, but such models require extensive inputs that are seldom available. Through model-data fusion (MDF), we combine climate and LAI time-series with an intermediate-complexity model to infer leaf N and yield. The DALEC-Crop model was calibrated for wheat leaf N and yields across field experiments covering N applications ranging from 0 to 200 kg N ha−1 in Scotland, UK. Requiring daily meteorological inputs, this model simulates crop C cycle responses to LAI, N and climate. The model, which includes a leaf N-dilution function, was calibrated across N treatments based on LAI observations, and tested at validation plots. We showed that a single parameterization varying only in leaf N could simulate LAI development and yield across all treatments—the mean normalized root-mean-square-error (NRMSE) for yield was 10%. Leaf N was accurately retrieved by the model (NRMSE = 6%). Yield could also be reasonably estimated (NRMSE = 14%) if LAI data are available for assimilation during periods of typical N application (April and May). Our MDF approach generated robust leaf N content estimates and timely yield predictions that could complement existing agricultural technologies. Moreover, EO-derived LAI products at high spatial and temporal resolutions provides a means to apply our approach regionally. Testing yield predictions from this approach over agricultural fields is a critical next step to determine broader utility.

scholarly journals Relaxation Times in Strictly Disk Systems

1971 ◽  
Vol 10 ◽  
pp. 15-19
Author(s):  
George B. Rybicki
Keyword(s):  
Numerical Experiments ◽  
Relaxation Times ◽  
Galactic Structure ◽  
Large Numbers ◽  
Order Of Magnitude ◽  
Vlasov Limit ◽  
The Mean ◽  
Gravitating Systems

AbstractIt is shown that the time of relaxation by particle encounters of self-gravitating systems in the plane interacting by 1/r2 forces is of the same order of magnitude as the mean orbit time. Therefore such a system does not have a Vlasov limit for large numbers of particles, unless appeal is made to some non-zero thickness of the disk. The relevance of this result to numerical experiments on galactic structure is discussed.

scholarly journals Different Hatching Rates of Floodwater Mosquitoes Aedes sticticus, Aedes rossicus and Aedes cinereus from Different Flooded Environments

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 279
Author(s):  
Anders Lindström ◽  
Disa Eklöf ◽  
Tobias Lilja
Keyword(s):  
Tap Water ◽  
Soil Samples ◽  
Mosquito Larvae ◽  
Retaining Structures ◽  
Retaining Structure ◽  
Large Numbers ◽  
Random Samples ◽  
Nuisance Species ◽  
Flooding Events ◽  
Hatching Rates

In the lower Dalälven region, floodwater mosquitoes cause recurring problems. The main nuisance species is Aedes (Ochlerotatus) sticticus, but large numbers of Aedes (Aedes) rossicus and Aedes (Aedes) cinereus also hatch during flooding events. To increase understanding of which environments in the area give rise to mosquito nuisance, soil samples were taken from 20 locations from four environmental categories: grazed meadows, mowed meadows, unkept open grassland areas and forest areas. In each location 20 soil samples were taken, 10 from random locations and 10 from moisture retaining structures, such as tussocks, shrubs, piles of leaves, logs, and roots. The soil samples were soaked with tap water in the lab, and mosquito larvae were collected and allowed to develop to adult mosquitoes for species identification. Fewer larvae hatched from mowed areas and more larvae hatched from moisture retaining structure samples than random samples. The results showed that Aedes cinereus mostly hatch from grazed and unkept areas and hatched as much from random samples as from structures, whereas Aedes sticticus and Aedes rossicus hatched from open unkept and forest areas and hatch significantly more from structure samples. When the moisture retaining structures in open unkept areas where Aedes sticticus hatched were identified it was clear that they hatched predominantly from willow shrubs that offered shade. The results suggest that Ae. sticticus and Ae. cinereus favor different flooded environments for oviposition.

GLOBAL FLUCTUATIONS FOR LINEAR STATISTICS OF β-JACOBI ENSEMBLES

2012 ◽  
Vol 01 (04) ◽  
pp. 1250013 ◽  
Author(s):  
IOANA DUMITRIU ◽  
ELLIOT PAQUETTE
Keyword(s):  
Gaussian Process ◽  
Covariance Matrix ◽  
Law Of Large Numbers ◽  
Test Functions ◽  
Linear Statistics ◽  
Jacobi Ensemble ◽  
Large Numbers ◽  
The Mean ◽  
Shifted Chebyshev Polynomial ◽  
Global Fluctuations

We study the global fluctuations for linear statistics of the form [Formula: see text] as n → ∞, for C1 functions f, and λ1, …, λn being the eigenvalues of a (general) β-Jacobi ensemble. The fluctuation from the mean [Formula: see text] turns out to be given asymptotically by a Gaussian process. We compute the covariance matrix for the process and show that it is diagonalized by a shifted Chebyshev polynomial basis; in addition, we analyze the deviation from the predicted mean for polynomial test functions, and we obtain a law of large numbers.

scholarly journals Limit Theorems and Fluctuations for Point Vortices of Generalized Euler Equations

2021 ◽  
Vol 182 (3) ◽  
Author(s):  
Carina Geldhauser ◽  
Marco Romito
Keyword(s):  
Euler Equations ◽  
Mean Field ◽  
Point Vortices ◽  
Positive Temperature ◽  
Field Limit ◽  
Mean Field Limit ◽  
Large Numbers ◽  
The Mean ◽  
Formal Solutions ◽  
2D Torus

AbstractWe prove a mean field limit, a law of large numbers and a central limit theorem for a system of point vortices on the 2D torus at equilibrium with positive temperature. The point vortices are formal solutions of a class of equations generalising the Euler equations, and are also known in the literature as generalised inviscid SQG. The mean-field limit is a steady solution of the equations, the CLT limit is a stationary distribution of the equations.

93 Does Spinal Bone Mineral Density Predict An Absolute 10 Year Probability of Sustaining A Major Osteoporotic Fracture

2021 ◽  
Vol 50 (Supplement_1) ◽  
pp. i12-i42
Author(s):  
A Nandi ◽  
N Obiechina ◽  
A Timperley ◽  
F Al-Khalidi
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Osteoporotic Fracture ◽  
Negative Correlation ◽  
Pearson Correlation ◽  
Fragility Fractures ◽  
Mineral Density ◽  
Major Osteoporotic Fracture ◽  
T Score ◽  
The Mean

Abstract Introduction Spine and hip bone mineral density (BMD) have previously been shown to predict the risk of sustaining future fractures. Although these have been shown in population studies, there is a paucity of trials looking at the relationship between BMD and 10 year probability of major osteoporotic fractures (Using FRAX UK without BMD) in patients with previous fragility fractures. Aims To evaluate the correlation between spinal T-score and an absolute 10 year probability of sustaining a major osteoporotic fracture (using FRAX without BMD) in patients with prior fragility fractures. Methods A retrospective cross-sectional analysis of 202 patients (29 males and 173 females) with prior fragility fractures attending a fracture prevention clinic between January and August 2019 was performed. Patients with pathological and high impact traumatic fractures were excluded. The BMD at the spine was determined using the lowest T-score of the vertebrae from L1 to L4. Using the FRAX (UK) without BMD, the absolute 10 year probability of sustaining a major osteoporotic fracture was calculated for each patient. Statistical analysis was performed using SPSS 26 software. Results The mean T-score at the spine was −1.15 (SD +/− 1.90) for all patients, −0.68 (SD +/− 0.45) for males and − 1.23 (SD +/− 0.14) for females. The mean FRAX score without BMD for major osteoporotic fracture was 18.5% (SD +/− 8.84) for all patients, 11.41% (SD +/−0.62) and 19.7% (SD +/−0.68) for males and females respectively. Pearson correlation coefficient showed a statistically significant, slightly negative correlation between spinal T- score and the FRAX (UK) without BMD (r = −0.157; p &lt; 0.05). Correlation was not statistically significant when males (r = 0.109; p = 0.59) and females (r = 0.148; p = 0.053) were considered independently. Conclusion In patients with prior fragility fracture spinal BMD has a statistically significant negative correlation with an absolute 10 year probability of sustaining a major osteoporotic fracture.

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