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The cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae) is an economically important insect pest of cotton in the United States. However, reports of cotton fleahopper infestation and its management in cotton fields are restricted primarily to Texas, Oklahoma, and Arkansas. The objective of this study was to understand the genetic diversity of cotton fleahopper populations infesting cotton in the cotton-growing areas of the United States. Amplified fragment length polymorphism markers were used to detect genetic diversity and to characterize geographic genotypes across the distribution of the cotton fleahopper in the United States. We used 172 individuals and 559 amplified fragment length polymorphism loci in this study and found significant, but low, level of genetic differentiation among geographic populations (FST = 0.02; P < 0.0001). Molecular fingerprints of cotton fleahopper populations were partitioned into three broad regional genetic populations with a western, central, and eastern distribution. The western (Arizona) and eastern (Florida, Georgia, South Carolina, and North Carolina) populations are genetically distinct, whereas the central (Texas, Oklahoma, Arkansas, Mississippi, Louisiana, and Alabama) population represents an admixed population, which include both western and eastern populations. These results suggest considerable gene flow among the populations within regions but restricted gene flow among populations from eastern and western region. [ABSTRACT FROM AUTHOR]

Several phytophagous insects exhibit distinct preference for their host plants. In widely distributed generalist insects, host preference can be influenced by geographic variation in host plant distribution and abundance as well as by prior experience. We have studied host preference of the cotton fleahopper, Pseudatomoscelis seriatus (Reuter), a pest of cotton in Texas and other neighboring states, by measuring olfactory orientation to horsemint (Monarda punctata L.) and cotton (Gossypium hirsutum L.). Horsemint is one of the primary, native, wild hosts of cotton fleahopper during late-spring and early summer in Texas, and it is commonly believed to be the main source of this pest in cotton. Although the abundance of horsemint, and therefore the fleahopper exposure to it, varies geographically, cotton fleahopper's preference for this native host-plant is maintained across two ecoregions in Texas, TX High Plains (Lubbock area) and Brazos Valley (College Station area). Similarly, preference for horsemint was retained regardless of prior experience with cotton throughout all the life stages of the insect. This fixed preference of cotton fleahopper to horsemint could be because of their ancestral insect-plant interaction, better fitness of cotton fleahopper on horsemint, and relatively low abundance of horsemint compared with cotton. Information gained from this study could be used to implement cultural control practices such as trap cropping, to develop attractants to monitor this pest, or both. [ABSTRACT FROM AUTHOR]

Automatic classification of shots extracted by news videos plays an important role in the context of news video segmentation, which is an essential step towards effective indexing of broadcasters’ digital databases. In spite of the efforts reported by the researchers involved in this field, no techniques providing fully satisfactory performance have been presented until now. In this paper, we propose a multi-expert approach for unsupervised shot classification. The proposed multi-expert system (MES) combines three algorithms that are model-free and do not require a specific training phase. In order to assess the performance of the MES, we built up a database significantly wider than those typically used in the field. Experimental results demonstrate the effectiveness of the proposed approach both in terms of shot classification and of news story detection capability. [ABSTRACT FROM AUTHOR]

A recent paper posed the question: "Graph Matching: What are we really talking about?". Far from providing a definite answer to that question, in this paper we will try to characterize the role that graphs play within the Pattern Recognition field. To this aim two taxonomies are presented and discussed. The first includes almost all the graph matching algorithms proposed from the lake seventies, and describes the different classes of algorithms. The second taxonomy considers the types of common applications of graph-based techniques in the Pattern Recognition and Machine Vision field. [ABSTRACT FROM AUTHOR]

Previous studies suggest grain sorghum, Sorghum bicolor (L.) Moench, acts as an early-season predator source for nearby cotton, Gossypium hirsutum L., in areas where their growing seasons overlap. However, few data exist on predator movement in this system, and proposed causes of movement have not been tested. Field studies in 2001 and 200'2 addressed both issues. Predator marking with rubidium was employed to measure predator movement between equal-sized areas of cotton and grain sorghum at three stages of grain sorghum phenology. Concurrent manipulative experiments in field cages tested for effects of phenology and aphid levels on movement by Hippodamia convergens Guérin-Méneville, a common predator in this system. Results from 2001 showed cotton gained 2.7 predators for every one lost to adjacent grain sorghum but that the collective movement of predators was similar among the three periods examined. The coccinellids H. convergens and Scymnus loweii Mulsant moved preferentially into cotton and seemed responsible for the overall pattern of predator movement between crops. For predators moving from grain sorghum into cotton, estimated rates of dispersal (15.8‐19.9 m/d) were found to be similar among all taxa studied. Cage experiments suggested both crop phenology and abundance of aphid prey in cotton and grain sorghum cause predator movement, but only the effect of phenology was consistent between years. These results support the idea that grain sorghum is a source of predators during cotton's early growth stages and suggest that grain sorghum may continue to contribute to natural enemy populations during later stages of cotton growth. [ABSTRACT FROM AUTHOR]

Background and objective: The mechanisms involved in the pathogenesis of cyclosporin A-induced gingival hyperplasia are not well understood. The present work aimed at developing a mouse model with the characteristics of the human process, i.e. time of appearance, dose dependency and the capacity of developing in a variety of genetic backgrounds. This model would present the advantages of using a very well known animal species, small and easy to handle, with a number of experimental reagents (antibodies, etc.) already available against its products. Methods: Three different strains of mice were used: CBA, Fl(C57B1 × DBA), Balb/c. Groups of mice received different concentrations of cyclosporin A (CSA) (10 mg/kg, 25 mg/kg and 40 mg/kg body weight) intraperitoneally five times a week. Anatomical and histological alterations were recorded at various time intervals. Results: All strains of mice presented gingival hyperplasia after 8 weeks of CSA treatment. A dose-dependency was observed with regard to the time of first appearance of alterations. Increased redness was seen in all animals at the sixth week, independent of the dosage used. Histologic examination exhibited increased vascularization, epithelial and connective tissue thickening, edema and a mononuclear infiltrate. Conclusions: It was possible to develop CSA-induced gingival hyperplasia in mice with the characteristics described in humans and other species. The use of this animal model may help in the elucidation of the process involved in CSA-induced gingival overgrowth. [ABSTRACT FROM AUTHOR]

In this paper we propose a reject rule applicable to a Multi-Expert System (MES). The rule is adaptive to the given domain and allows the achievement of the best trade-off between reject and error rates as a function of the costs attributed to errors and rejects in the considered application. The results of the method are particularly effective since the method does not rely on particular statistical assumptions, as other reject rules. An experimental analysis carried out on publicly available databases is reported together with a comparison with other methods present in the literature. [ABSTRACT FROM AUTHOR]

A prey-specific gut content enzyme-linked immunosorbent assay (ELISA) was used to identify predation of eggs of bollworm, Helicoverpa zea (Boddie), by Orius spp. in commercial cotton fields in Texas. Degradation of the egg protein began immediately after O. insidiosus fed on an egg. However, the protein antigen was detectable in the predator for approximately 10 h after feeding. The antigen retention time provided a conservative estimate of predation and insured that when predation was detected it occurred on the day predators were collected. The percentage of individual of Orius spp. that was positive by ELISA for the egg antigen varied throughout each growing season. The highest frequency of positive responses occurred before cotton bloom and after peak bloom. [ABSTRACT FROM AUTHOR]

The population dynamics of the bollworm, Helicoverpa zea (Boddie), and its associated natural enemies were studied in insecticide-free, commercial, short-season cotton fields from 1991 to 1995 in the southern Blacklands of Texas. Bollworm had one discernable generation per season in cotton. Partial ecological life tables constructed for each annual generation indicated that 71–95% mortality could be consistently expected in the egg and first-instar life stages. Intrageneration mortality ranged from 93 to 99%. Unexplained mortality was the leading cause of mortality in 1991–1993, but not in 1994 and 1995 when predation due to Orius spp. was partitioned. Unexplained mortality included abiotic as well as biotic factors. Parasite activity was consistently low. Egg parasitization by Trichogramma spp. averaged 3.4%. Larval parasitization rarely exceeded 5% and no larval parasitization was found in 1993. Microplitis croceipes (Cresson) was the most common larval parasite collected. Predation of bollworm eggs by Orius insidiosus (Say), the numerically dominant predator in the system, was estimated using ELISA in 1994 and 1995. O. insidiosus was the most important mortality factor when measured consuming 84 and 71% of the eggs in 1994 and 1995, respectively. [ABSTRACT FROM PUBLISHER]

A serial three stage multi-expert system for facing the problem of signature verification is proposed. The whole decision process is organised into successive stages, each using a very reduced set of features for recognising forgeries and providing information about the reliability of the recognition process. The first expert, adopting only a single global feature, is devoted to the elimination of random and simple forgeries. The second stage receives only those signatures not classified as false by the first stage (i.e. those signatures really genuine or forgeries reproduced in a skilled way), and adopts a single specific feature suitable for isolating skilled forgeries. Both of these two stages employ suitable criteria for estimating the reliability of the performed classification, so that, in case of uncertainty, the signature is forwarded to a final stage which takes the final decision, taking into account the decisions of the previous stages together with the corresponding reliability estimations. The proposed multi-stage automatic signature verification system has been tested on a database of signatures produced by 49 different writers. The experimental analysis highlights the effectiveness of the approach: the proposed system employing only two features, used in distinct moments of the decision process, performs better than other systems, employing larger feature set (including the features used in the proposed system) and performing classification in a single stage. [ABSTRACT FROM AUTHOR]

This paper proposes a structural description scheme using second order primitives, in particular circular arcs. In this framework, a distance measure between pairs of circular arcs and relations among them is introduced, and its main properties are discussed. This measure accomplishes some perceptive criteria for increasing its efficiency: it proved applicable in a wide class of application domains characterised by high variability in the shape of the visual patterns, where a structural approach is particularly useful. The description method together with the distance have been experimentally validated in the context of the recognition of handwritten digits coming from a standard character database. [ABSTRACT FROM AUTHOR]

Recognition systems based on a combination of different experts have been widely investigated in the recent past. General criteria for improving the performance of such systems are based on estimating the reliability associated with the decision of each expert, so as to suitably weight its response in the combination phase. According to the methods proposed to-date, when the expert assigns a sample to a class, the reliability of such a decision is estimated on the basis of the recognition rate obtained by the expert on the chosen class during the training phase. As a consequence, the same reliability value is associated with every decision attributing a sample to a same class, even though it seems reasonable to take into account its dependence on the quality of the specific sample. We propose a method for estimating the reliability of each single recognition act of an expert on the basis of information directly derived from its output. In this way, the reliability value of a decision is more properly estimated, thus allowing a more precise weighting during the combination phase. The definition of the reliability parameters for widely used classification paradigms is discussed, together with the combining rules employing them for weighting the expert opinions. The results obtained by combining four experts in order to recognise handwritten numerals from a standard character database are presented. Comparison with classical combining rules is also reported, and the advantages of the proposed approach outlined. [ABSTRACT FROM AUTHOR]

Sansone, Weir, Harpster, and Morgan (1992) found that individuals intentionally regulated their interest in an activity when they had both the need (the task was boring) and a reason to exert the effort (an ostensible health benefit). The present study examined Hardiness and Conscientiousness as moderators of this self-regulatory process when individuals had the option of quitting in addition to the options of persisting and of engaging in interest-enhancing strategies. Undergraduates performed a boring copying activity under instructions to stop when they felt they could evaluate the task. Half were told that their evaluations would help researchers develop good jobs for others (Benefit). Results indicated high hardy individuals copied more letters when they were provided the additional Benefit information, and this effect was mediated through their attempt to make the task more interesting. High conscientious individuals persisted longer than individuals lower in conscientiousness independently of the benefit manipulation or strategy use. Implications of individual differences in self-regulation of motivation are discussed. [ABSTRACT FROM AUTHOR]

Coronal dental plaque from each of 12 caries-positive subjects (Group I) was pooled from "white spot" tooth surface areas and, separately, from sound surface areas; sound surface areas in each of 18 caries-free subjects (Group II) were sampled similarly. Two samples, one consisting of material from a root-surface lesion and another of plaque from a sound root-surface area, were obtained from each of another 10 subjects (Group III). The samples from Groups I and II were evaluated for: (1) pH-lowering potential in vitro with dispersed plaque suspensions, excess glucose supply, and a 60-minute test; (2) the levels of mutans streptococci (MS) and lactobacilli; and (3) the distribution of the predominant non-mutans streptococci (non-MS) according to their final pH in glucose broth; only microbial analysis was done for the Group III samples. The levels of the MS were generally positively associated with caries. A weaker positive association was found for the levels of those non-MS capable of acidogenesis at low pH (final pH < 4.4). The latter generally far outnumbered the MS in all types of samples. The levels of lactobacilli were nearly always very low. The pH-lowering potential (final pH and pH drop rate) was higher for plaque from "white spot" areas than for plaque from sound surface areas (Group I). The samples from caries-free subjects (Group II), however, exhibited a pH-lowering potential which was not significantly different from that of both types of samples from the caries-active subjects (Group I). Collectively, the findings suggest that the role of non-MS capable of acidogenesis at low pH in caries development merits further study. [ABSTRACT FROM AUTHOR]

Samples of human dental plaque were obtained from sound tooth surfaces in the lower anterior and upper posterior areas of each of 11 subjects with various degrees of caries experience. Both types of plaque were compared for: (1) their pH-lowering potential [pH at 10 and 60 min after sugar addition and the pH drop between 0 and 10 min (delta pH)] with an in vitro method involving dispersed plaque suspensions and excess glucose supply; (2) the proportions of mutans streptococci; and (3) the distribution of the predominant non-mutans streptococci according to their final pH in glucose broth. Compared with plaque from the lower anterior area, plaque from the upper posterior area exhibited a significantly higher pH-lowering potential, i.e., a lower pH at 10 and 60 min and a greater delta pH and significantly higher levels of mutans streptococci. The final pH values for the non-mutans streptococci exhibited a wide range from about 4.4 to over 5.0. The proportions of such organisms designated as capable of acidogenesis at low pH (final pH < 4.6), whether expressed as a percentage of the total non-mutans streptococci or of the total plaque flora, were significantly increased in plaque from the upper posterior area. The proportions of non-mutans streptococci capable of acidogenesis at low pH in plaque from the upper posterior area were also significantly increased, with decreasing pH values at 10 and 60 min. The findings strengthen the link between the capacity of the plaque flora for acidogenesis at a low pH and its pH-lowering potential as well as the role of bacterial acidogenesis at a low pH as an oral ecological determinant. [ABSTRACT FROM AUTHOR]

Samples of human dental plaque were pooled from several "white spot" smooth tooth surface areas as well as from several clinically-sound tooth surface areas in each of 12 caries-positive college students. Each of the two samples from each subject was used for the determination of: (1) pH-lowering potential in vitro involving dispersed plaque suspensions, excess glucose supply, and a 60-minute test, and (2) the proportions of mutans streptococci and lactobacilli. When all subjects were considered, plaques from "white spot" areas, as compared with samples from sound surface areas, were characterized by significantly higher proportions of mutans streptococci, a lower starting ("resting") pH, a faster rate of pH drop between pH 6.0 and 5.0, and a lower minimum pH of the suspension; the lactobacillus proportions were generally very low in both types of plaques. For individual subjects, however, the proportions of mutans streptococci in plaque associated with "white spot" areas showed a wide range (0.001-10.0%), and samples with high as well as low levels of these micro-organisms could exhibit a high rate of pH drop and a low pH minimum. This suggests that, besides mutans streptococci and lactobacilli, other bacteria capable of acidogenesis at a low pH may contribute to the high pH-lowering potential exhibited by many plaques. [ABSTRACT FROM AUTHOR]

A "reverse" hybridization method is described, in which s\whole chromosomal DNA was extracted from 10-20 colonies of "unknown" stains in pure culture and labelled with digoxigenin by a random primer technique. DNA probe were prepared from a total of 23 strains and hybridized with targets containing 100 ng purified, denatured DNA from 38 reference strains fixed to nitrocellulose. 21/23 digoxigenin-labelled DNA probes successfully detected all members of the homologous species present on filters. Probes to Fusobacterium nucleatum strains 364 and MG detected 3/4 and 1/4 members of this species, respectively; 13/23 probes were 100% specific, but cross reactions between 10 probes and DNA targets from closely related, heterologous species occurred in 15/834 possible instances. False-positive reactions that occurred between closely related species were, however, easily distinguished and did not prevent the accurate identification of probe strains. Digoxigenin-labelled probes were capable of detecting 100 pg of homologous DNA. The reverse hybridization procedure allows identification of grouping of a large number of isolates within 3 days and provides a more economical means of characterizing subgingival isolates than predominant cultivable techniques and conventional phenotypic testing. This method could be adapted for the direct identification of microorganisms in subgingival plaque samples. [ABSTRACT FROM AUTHOR]

Two methods were compared for the extraction of DNA from small numbers of bacterial cells. The first method involve lysis of cells with SDS in the presence of proteinase K, treatment with hexadecyltrimethyl ammonium bromide (CTAB) and precipitation of DNA with iospropanol. In the second method, DNA was extracted by treatment of the cells with guanidine hydrochloride (GHCI) and precipitated with ethanol. Thirty strains of representative gram positive and gram negative species were included in the study. Preparations derived from confluent growth on one-quarter of the surface of agar plates and from 108 cells were subjected to each extraction procedure and analyzed for their content of DNA, RNA and protein. The suitabilities of the resultant DNA for restriction enzyme digestion and biotin- labelling by a random primer technique were also assessed. In general, the CTAB method yielded greater amounts of DNA than the GHCI procedure. RNA was present in most preparations of both types, but in amounts detectable only be agarose gel electrophoresis. The latter technique also revealed that DNA was not excessively sheared by either procedure. Protein was detected in some CTAB and GHCI preparations, by was not consistently associated with one or the other method. DNA obtained by both methods could be digested by the restriction enzyme EcoR I. In addition, biotin-labelled DNA probes prepared from CTAB and GHCI> preparations were capable of hybridizing with homoglogous target DNA fixed to nitrogecellulose, Since the CTAB method was consistently successful in recovering DNA from preparations containing 108 cells, it may be more suitable for the direct treatment of single colonies taken from primary isolation plates or plaques samples. [ABSTRACT FROM AUTHOR]

The use of a wavelet‐Markov local descriptor, which exploits joint dependencies among wavelet coefficients, for fingerprint liveness detection, is proposed. On the LivDet 2009 datasets, a properly trained support vector machine classifier based on this descriptor guarantees an average error below 3%, as opposed to the 8% average error of the best conventional techniques. [ABSTRACT FROM AUTHOR]

The use of a wavelet-Markov local descriptor, which exploits joint dependencies among wavelet coefficients, for fingerprint liveness detection, is proposed. On the Liv Det 2009 datasets, a properly trained support vector machine classifier based on this descriptor guarantees an average error below 3%, as opposed to the 8% average error of the best conventional techniques. [ABSTRACT FROM AUTHOR]