15 research outputs found
An 800 MHz 0.35 um CMOS Clock Tree and PLL based on a new charge-pump circuit
The paper presents the design of an 800 MHz PLL implemented in a 0.35 ÎŒm CMOS technology. A novel charge pump circuit has been introduced in order to increase the frequency range of the PLL. A clock tree with buffers in the internal nodes has been designed for a chip of dimensions 1 cmĂ1 cm. The PLL supports internal to external clock frequency ratios of 1, 2, 4 and 8. PLL and clock tree have been used for power reduction by clock domain partitioning
Distribution Quality of Agrochemicals for the Revamping of a Sprayer System Based on Lidar Technology and Grapevine Disease Management
Grapevines are one of the most intensely treated crops with a high potential risk to health and biodiversity. Thus, the distribution control of agrochemicals is crucial to obtain a high quality and sustainable product for intensive viticulture. Although the search for systems to reduce the waste of chemical products is consistent in some countries, such as Italy, the machinery used are obsolete. The development of an upgrading system for sprayers can be a good compromise to achieve the pollution reduction without requiring huge investments. Field tests were conducted using a LIDAR-based prototype coupled to a commercial sprayer. This study tested the distribution performance using water-sensitive papers and evaluated the infections of grapevine downy and powdery mildews. The results showed a distribution in the vegetation gaps with a higher frequency in the coverage classes >20% in the standard treatment and 10â15% in the LIDAR treatment. Treatments performed with LiDAR reduced the incidence of downy mildew and severity of powdery mildew. The innovative sprayer reduces the distribution of agrochemicals thanks to the on/off control of the nozzles in the voids of vegetation and, meanwhile, controls vineyard fungal disease, so it can be a good way to meet the sustainability and quality of the production
Tasks Performed by Different Groups of Foragers and Regulation of Foraging Activity in the Mediterranean Harvest Ant Messor wasmanni (Hymenoptera, Formicidae)
The moment-to-moment tasks performed by an individual can change in response to a shift of internal, e.g. body size or age, and external conditions, e.g. the number of workers currently engaged in another task. For this reason, the term âtask allocationâ is replacing the earlier concept of âdivision of laborâ for describing an invariable association between worker body size and task. In the present study we hypothesized that, in the absence of changing conditions, different sized workers tend to perform different tasks. We also evaluated, using baits, the ability of colonies to regulate foraging activity through interactions between outgoing and returning foragers and the effect of ground temperature on the relative participation of different-sized workers to the foraging activity. Results suggest the existence in large and well-established colonies inhabiting a typical Mediterranean grassland area, of different-sized workers performing different tasks outside the nests. Moreover, we noticed the ability of colonies to adjust the relative participation of different sized foragers when provided with different-sized resources (baits). Finally, we recorded an effect of temperature on the average size of foragers, although no effect on size distribution was found
Utilizzo di un metodo citofluorimetrico per la conta di Listeria monocytogenes nei challenge test
Anxiety control and metacognitive beliefs mediate the relationship between inflated responsibility and obsessive compulsive symptoms
Research has indicated that beliefs about inflated responsibility, beliefs about perceived control over anxiety-related events and reactions (anxiety control) and metacognitive beliefs about the need to control thoughts are associated with obsessive compulsive symptoms. In the current study we tested a mediation model of the interactions between these variables in predicting obsessive compulsive symptoms. Thirty-seven individuals with obsessive compulsive disorder and 31 controls completed the following self-report instruments: the Responsibility Attitude Scale, the Anxiety Control Scale, the Beliefs about Need to Control Thoughts sub-scale of the Metacognitions Questionnaire 30, and the Padua Inventory. Mann-Whitney U tests revealed that participants in the clinical group scored significantly higher than those in the non-clinical group on all variables. In the mediation model we found that the relationship between beliefs about inflated responsibility and obsessive compulsive symptoms was fully mediated by anxiety control and beliefs about the need to control thoughts. These findings provide support for the significant role played by beliefs about control in predicting the severity of obsessive compulsive symptoms.5 page(s
Differences in exploitation and interference ability between two dominant ants: the invasive Argentine ant ( Linepithema humile
The influence of stress on the relationship between cognitive variables and measures of eating disorders (in healthy female university students): a quasi-experimental study
OBJECTIVE: Perfectionism, poor self-esteem and stress have all been described as important risk factors for eating disorders. The purpose of this study was to assess whether a stressful situation is significantly correlated to and associated with significantly higher levels of perfectionism, stress, quantifiable measures of eating disorders, and with significantly lower levels of self-esteem in a non-clinical sample. METHOD: Thirty-five female university students completed the Multidimensional Perfectionism Scale, the Rosenberg Self-Esteem Scale, the Perceived Stress Scale, and the Eating Disorder Inventory two times; once on an average university day and once on the day of an exam. Descriptive statistics and t-tests were calculated to verify whether a stressful situation was associated with a significant difference in levels of perfectionism, self-esteem, stress, and measures of eating disorders. Bivariate correlations were calculated for both the stress and non-stress situation, to observe how the dimensions of perfectionism, self-esteem, and stress were associated with measures of eating disorders. RESULTS: During the stress situation, the study participants had, on average, significantly higher levels of concern over mistakes, body dissatisfaction, drive for thinness, and perceived stress. Bivariate correlations revealed that during the stress situation perceived stress, cognitive variables and measures of eating disorders showed significant correlations with each other that were absent in the non stress situation. DISCUSSION: The results of the present study suggest that the dimensions of pathological perfectionism, low self-esteem, and perceived stress are related to an increase in dieting thoughts and dissatisfaction with body aspect in non-clinical women during a performance that could potentially challenge the perception of their self-esteem. The stressful situation can be interpreted as an experience of invalidation, which could explain the connection between cognitive constructs and behaviours related to eating disorder
Iridoids and volatile pheromones of Tapinoma darioi ants: chemical differences to the closely related species Tapinoma magnum
Iridoids and volatile pheromones of Tapinoma darioi ants: chemical differences to the closely related species Tapinoma magnum
Tapinoma species, and more general dolichoderine ants, are able to produce a variety of volatile compounds they use as chemical defense, alarm, and communication pheromones. Among these, iridoids and volatile ketones are the predominant molecule classes produced by the anal glands of these ants. A recent taxonomic revision of the genus Tapinoma in Europe revealed that the supercolonial species Tapinoma nigerrimum consists of a complex of four cryptic species. Two of them, Tapinoma magnum and the newly described Tapinoma darioi, are closely related species that evolutionary diverged recently. In this work, we determine and characterize the chemical profile of pheromones and volatile compounds of two Tapinoma species. From a chemical point of view, T. darioi and T. magnum show both qualitative and quantitative differences in the pheromones produced, supporting the taxonomic revision of the T. nigerrimum complex. Our data confirm T. darioi and T. magnum as separate species also from a biochemical point of view demonstrating the value of chemotaxonomy as a suitable tool for integrative studies of species differentiation even for closely related taxa.We want to thank Prof. Wilhelm Boland and Nanxia Fu (Max Planck institute for Chemical Ecology, Jena, Germany) for the technical support and for kindly providing Phaedon cochlearia extract. A.F. and L.W. acknowledge partial support by the Leibniz association through a Leibniz-DAAD postdoctoral fellowship to A. F
Iridoids and volatile pheromones of Tapinoma darioi ants. Chemical differences to the closely related species Tapinoma magnum
Tapinoma species, and more general dolichoderine ants, are able to produce a variety of volatile compounds they use as chemical defense, alarm, and communication pheromones. Among these, iridoids and volatile ketones are the predominant molecule classes produced by the anal glands of these ants. A recent taxonomic revision of the genus Tapinoma in Europe revealed that the supercolonial species Tapinoma nigerrimum consists of a complex of four cryptic species. Two of them, Tapinoma magnum and the newly described Tapinoma darioi, are closely related species that evolutionary diverged recently. In this work, we determine and characterize the chemical profile of pheromones and volatile compounds of two Tapinoma species. From a chemical point of view, T. darioi and T. magnum show both ualitative and quantitative differences in the pheromones produced, supporting the taxonomic revision of the T. nigerrimum complex. Our data confirm T. darioi and T. magnum as separate species also from a biochemical point of view demonstrating the value of chemotaxonomy as a suitable tool for integrative studies of species differentiation even for closely related taxa