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At least 739 records · Page 41Linked to original sources
PubMed2005

A new versatile and robust mite trap for detection and monitoring of storage mites in the cereal and allied industries.

Storage mites are important primary pests but present methods for trapping them are either rudimentary or have several limitations. These prevent effective early detection or reliable monitoring of mites in the food, animal feed and associated industries. The BT Trap is the first trap designed specifically for the detection and monitoring of mite infestation. This trap is made up of a mixed food base lure held in a robust adjustable housing. It is user friendly, requires an exposure period of only 4 days and can be used in a dusty environment. The performance of the BT Trap was evaluated in the laboratory and the mean minimal capture rate of mites was 62%. In a comparative field trial, this trap detected significantly more mites than the bait bag or the fishmeal trap. The trap's performance was also assessed in four different types of premises. These were premises engaged in the production of cereal based dry pet food, specialist animal feed, traditional cheese, and in the finished cereal section of a large transit storage warehouse. A total of 17 genera or species of storage and predatory mites was detected in these four premises, with at least seven species detected in each of these premises. This study confirms that the BT Trap was able to function under the rigours of use in the field. It has demonstrated its potential as a useful tool for early detection and monitoring of mites in production premises. It also provided information that was vital for improving existing mite control measures and in implementing effective management strategies.

Acaridae↗
PubMedDate not supplied

Variable selection and specification of robust QSAR models from multicollinear data: arylpiperazinyl derivatives with affinity and selectivity for alpha2-adrenoceptors.

Two QSAR models have been identified that predict the affinity and selectivity of arylpiperazinyl derivatives for alpha1 and alpha2 adrenoceptors (ARs). The models have been specified and validated using 108 compounds whose structures and inhibition constants (Ki) are available in the literature [Barbaro et al., J. Med. Chem., 44 (2001) 2118; Betti et al., J. Med. Chem., 45 (2002) 3603; Barbaro et al., Bioorg. Med. Chem., 10 (2002) 361; Betti et al., J. Med. Chem., 46 (2003) 3555]. One hundred and forty-seven predictors have been calculated using the Cerius 2 software available from Accelrys. This set of variables exhibited redundancy and severe multicollinearity, which had to be identified and removed as appropriate in order to obtain robust regression models free of inflated errors for the beta estimates - so-called bouncing betas. Those predictors that contained information relevant to the alpha2 response were identified on the basis of their pairwise linear correlations with affinity (-log Ki) for alpha2 adrenoceptors; the remaining variables were discarded. Subsequent variable selection made use of Factor Analysis (FA) and Unsupervised Variable Selection (UzFS). The data was divided into test and training sets using cluster analysis. These two sets were characterised by similar and consistent distributions of compounds in a high dimensional, but relevant predictor space. Multiple regression was then used to determine a subset of predictors from which to determine QSAR models for affinity to alpha2-ARs. Two multivariate procedures, Continuum Regression (the Portsmouth formulation) and Canonical Correlation Analysis (CCA), have been used to specify models for affinity and selectivity, respectively. Reasonable predictions were obtained using these in silico screening tools.

Models, Molecular↗
PubMed1986

Robust estimation of standard curves for protein molecular weight and linear-duplex DNA base-pair number after gel electrophoresis.

An accurate procedure for estimating linear-duplex DNA base-pair numbers and protein molecular weights after electrophoresis in single concentration gels is presented. A robust modified hyperbola was found to be superior for determining molecular weights and base-pair numbers for a set of known standards when compared with the conventional log transformation and a similar hyperbolic model. We describe the use of a soft laser-scanning densitometer to measure band-migration distances of wet, stained polyacrylamide gels for proteins and photographic negatives of agarose gels containing DNA stained with ethidium bromide. This automated densitometric method was more accurate than existing methods. A BASIC computer program detailing the procedure is included.

Base Composition↗
PubMed1987

Release of endogenous gamma-aminobutyric acid from vocalization nucleus, the robust nucleus of the archistriatum of zebra finch in vitro.

The release of gamma-aminobutyric acid (GABA) from the robust nucleus of the archistriatum (RA) of the zebra finch was examined in slice preparations. Potassium-induced depolarization caused calcium-dependent release of GABA. GABA release by veratrine was blocked by tetrodotoxin. Electrical stimulation of fibers dorsal to RA also released GABA. There was no sex difference in GABA release per wet weight of RA, while the size of the female RA is smaller than that of the male RA.

Animals↗
PubMed1983

A robust-digital QRS-detection algorithm for arrhythmia monitoring.

The success of automated patient monitoring is primarily dependent on the ability to detect normal as well as bizarre QRS-complexes. In this paper a new robust single lead QRS-detection algorithm is presented. The QRS detector can be separated into five different blocks, namely, a noise filter, a differentiator, an energy collector, a minimal distance classifier, and a minimax trimmer. Each block accounts for some characteristic features of QRS complexes (steepness, duration, etc.). The time delay introduced by this algorithm for making a decision is less then one second, allowing real-time applications. The performance of the QRS detector is analyzed and results are presented.

Arrhythmias, Cardiac↗
PubMed1986

On robust partial discriminant analysis as a decision-making tool with clinical and analytical chemical data.

Classification is one of the fundamental goals of science and is basic to the diagnosis of disease. Unfortunately, classifying objects (e.g., patients) on the basis of clinical and/or laboratory experimental observations into various groups can be difficult when the groups overlap or contain outlying points. Recently, Broffitt, Randles, and co-workers proposed a procedure, robust partial discriminant analysis (RPDA) for dealing with such problems, but testing of the procedure was limited to Monte Carlo simulation. In this study, RPDA was applied to real data, in order to compare its effectiveness with ordinary discriminant analysis, as well as to determine if RPDA was a suitable procedure to use to classify chemical compounds on the basis of experimental observations and as a tool in the diagnosis of disease (in particular, multiple sclerosis and thyrotoxicosis), with data based on experimental and clinical observations. The resulting RPDA classifications were an improvement over those obtained from ordinary discriminant analysis.

Aldehydes↗
PubMed1984

Peritz' F test: basic program of a robust multiple comparison test for statistical analysis of all differences among group means.

Peritz' F test has previously been found to be the most robust statistical multiple comparison test able to hold all comparisons among group means to a given experimentwise error rate. A BASIC program which will perform this test quickly on a desk-top microcomputer, needing fewer than 11 kbytes of RAM memory, is presented. The program is run in the author's laboratory using an inexpensive VIC-20 computer.

Computers↗
PubMed1985

Moments of the power spectral density estimated from samples of the autocorrelation function (a robust procedure for monitoring changes in the statistical properties of lengthy non-stationary time series such as the EEG.

Accurate estimates of the statistical moments of the power spectral density (PSD) are obtained without computing the Fourier transform of the associated time series. An innovative analytical procedure is derived which reduces the problem to that of summing a small number of weighted samples of the autocorrelation function (ACF). This result significantly reduces the computational requirements for generating meaningful PSD shape descriptors and thus is especially important in biomedical applications where the cost and effort of monitoring lengthy non-stationary time series is a serious practical limitation. In addition the procedure is robust and therefore can be rigorously applied to any stochastic process to estimate its fundamental statistical properties.

Adult↗
PubMed1992

Robust adaptive parameter estimators in arrhythmia detection.

The authors consider the statistical analysis of threshold crossing intervals, as applied to estimation of tachycardia rates from intracavitary electrograms. The authors developed a class of robust algorithms designed to produce minimum variance estimates for tachycardia rates. The authors formulated the algorithms using order statistic filters, and obtained the minimum variance unbiased order statistic estimator. The potential gain in efficiency achieved by this approach is demonstrated via a representative example. The results indicated that the order statistics operator can produce dramatic reductions for typical errors in error variance as compared to linear estimators.

Algorithms↗
PubMed1991

Robust growth hormone (GH) secretion in aged female rats co-administered GH-releasing hexapeptide (GHRP-6) and GH-releasing hormone (GHRH).

Aging is associated with a blunted growth hormone (GH) secretory response to GH-releasing hormone (GHRH), in vivo. The objective of the present study was to assess the effects of aging on the GH secretory response to GH-releasing hexapeptide (GHRP-6), a synthetic GH secretagogue. GHRP-6 (30 micrograms/kg) was administered alone or in combination with GHRH (2 micrograms/kg) to anesthetized female Fischer 344 rats, 3 or 19 months of age. The peptides were co-administered to determine the effect of aging upon the potentiating effect of GHRP-6 on GHRH activity. The increase in plasma GH as a function of time following administration of GHRP-6 was lower (p less than 0.001) in old rats than in young rats; whereas the increase in plasma GH secretion as a function of time following co-administration of GHRP-6 and GHRH was higher (p less than 0.001) in old rats than in young rats (mean Cmax = 8539 +/- 790.6 micrograms/l vs. 2970 +/- 866 micrograms/l, respectively; p less than 0.01). Since pituitary GH concentrations in old rats were lower than in young rats (257.0 +/- 59.8 micrograms/mg wet wt. vs. 639.7 +/- 149.2 micrograms/mg wet wt., respectively; p less than 0.03), the results suggested that GH functional reserve in old female rats was not linked to pituitary GH concentration. The differential responses of old rats to individually administered and co-administered GHRP-6 are important because they demonstrate that robust and immediate GH secretion can occur in old rats that are appropriately stimulated. The data further suggest that the cellular processes subserving GH secretion are intact in old rats, and that age-related decrements in GH secretion result from inadequate stimulation, rather than to maladaptive changes in the mechanism of GH release.

Aging↗
PubMed1991

On the robustness of regular systems of inbreeding.

Half-sib, first cousin, half nth cousin, and nth cousin mating systems are robust in that small deviations from the mating structure will not significantly alter the levels of genetic identity or effect qualitative distinctions between the models. Substitution of nearest kin in matings may either increase or decrease the level of homozygosity depending on the mating structure; the effect of a single error in the mating structure is not an accurate indicator of the equilibrium resulting from recurrent errors. Models of mixed half nth cousin or nth cousin mating show that the relative frequency of the lowest order inbred mating essentially determines the level of homozygosity. Any positive relative frequency of more distant matings will reduce the probability of identity by descent under half-sib or first cousin mating to less than 1.

Alleles↗
PubMed1994

Humans combine the optic flow with static depth cues for robust perception of heading.

The retinal flow during normal locomotion contains components due to rotation and translation of the observer. The translatory part of the flow-pattern is informative of heading, because it radiates outward from the direction of heading. However, it is not directly accessible from the retinal flow. Nevertheless, humans can perceive their direction of heading from the compound retinal flow without need for extra-retinal signals that indicate the rotation. Two classes of models have been proposed to explain the visual decomposition of the retinal flow into its constituent parts. One type relies on local operations to remove the rotational part of the flow field. The other type explicitly determines the direction and magnitude of the rotation from the global retinal flow, for subsequent removal. According to the former model, nearby points are most reliable for estimating one's heading. In the latter type of model the quality of the heading estimate depends on the accuracy with which the ego-rotation is determined and is therefore most reliable when based on the most distant points. We report that subjects underestimate the eccentricity of heading, relative to the fixated point in the ground plane, when the visible range of the ground plane is reduced. Moreover we find that in perception of heading, humans can tolerate more noise than the optimal observer (in the least squares sense) would do if only using optic flow. The latter finding argues against both schemes because ultimately both classes of model are limited in their noise tolerance to that of the optimal observer, which uses all information available in the optic flow. Apparently humans use more information than is present in the optic flow. Both aspects of human performance are consistent with the use of static depth information in addition to the optic flow to select the most distant points. Processing of the flow of these selected points provides the most reliable estimate of the ego-rotation. Subsequent estimates of the heading direction, obtained from the translatory component of the flow, are robust with respect to noise. In such a scheme heading estimates are subject to systematic errors, similar to those reported, if the most distant points are not much further away than the fixation point, because the ego-rotation is underestimated.

Algorithms↗
PubMed1995

Increase in plasma TYR-MIF-1-like immunoreactivity after hypophysectomy is robust and reversible by corticosterone.

Tyr-MIF-1-like immunoreactivity (Tyr-MIF-1-LI) was measured in the plasma of hypophysectomized rats. The concentrations were increased in every rat examined, regardless of sex or time after hypophysectomy, and ranged from 2.5 to 10 times greater than the concentrations in intact rats. The elevated concentrations were not decreased by replacement by thyroxine, estrogen and progesterone, or acute injection of corticosterone. Chronic administration of physiological doses of corticosterone, however, did reduce the concentrations to normal. High performance liquid chromatography of tritiated Tyr-MIF-1 incubated at 37 degrees C for 3 min in plasma obtained by hypophysectomized rats eliminated the possibility that reduced degradation of Tyr-MIF-1 explained the increased concentrations. Thus, the increase in Tyr-MIF-1-LI in the plasma of hypophysectomized rats is robust and reversible by chronic replacement of corticosterone.

Animals↗
PubMed1996

Developmental changes in axon terminals visualized by immunofluorescence for the growth-associated protein, GAP-43, in the robust nucleus of the archistriatum of the zebra finch.

Two afferents to the robust nucleus of the archistriatum (RA) are important for song learning by the zebra finch. The growth-associated protein-43 (GAP-43) has been used as a molecular marker for axonal growth. In these experiments, the axon terminals were visualized by immunofluorescence with antibodies against GAP-43 and we studied the developmental processes in the zebra finch after the invasion of the RA by afferent fibers. After waiting at the dorsal border of the RA before invading the RA, the axon terminals from the higher vocal center (HVc) first contacted the soma, and then redistributed and established synapses on the dendrites. This initial contact with the soma may be closely related to the neurotrophic properties of the axon terminals from the HVc neurons.

Animals↗
PubMed1987

Women's schooling and children's health. Are the effects robust with adult sibling control for the women's childhood background?

Women's schooling is thought to have an important positive impact on children's health and nutrition in developing countries. A special adult sister sample from Nicaragua is used to explore this relation. Standard individual reduced-form estimates suggest a strong positive impact. With control for the unobserved common childhood family background characteristics shared by the sisters, the impact of women's schooling on nutrition is quite robust, but on the health outcomes declines substantially or evaporates. Thus, contrary to the standard estimates, mother's schooling does not appear to improve substantially their children's health outcomes, though it does seem to increase their nutrient intakes.

Child↗