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Search Results: 1 - 10 of 9810 matches for " Valeria Bruno "
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Transport Properties of Melanosomes along Microtubules Interpreted by a Tug-of-War Model with Loose Mechanical Coupling
Sebastián Bouzat, Valeria Levi, Luciana Bruno
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0043599
Abstract: In this work, we explored theoretically the transport of organelles driven along microtubules by molecular motors of opposed polarities using a stochastic model that considers a Langevin dynamics for the cargo, independent cargo-motor linkers and stepping motion for the motors. It has been recently proposed that the stiffness of the motor plays an important role when multiple motors collectively transport a cargo. Therefore, we considered in our model the recently reported values for the stiffness of the cargo-motor linker determined in living cells (~0.01 pN/nm, [1]) which is significantly lower than the motor stiffness obtained in in vitro assays and used in previous studies. Our model could reproduce the multimodal velocity distributions and typical trajectory characteristics including the properties of the reversions in the overall direction of motion observed during melanosome transport along microtubules in Xenopus laevis melanophores. Moreover, we explored the contribution of the different motility states of the cargo-motor system to the different modes of the velocity distributions and could identify the microscopic mechanisms of transport leading to trajectories compatible with those observed in living cells. Finally, by changing the attachment and detachment rates, the model could reproduce the different velocity distributions observed during melanosome transport along microtubules in Xenopus laevis melanophores stimulated for aggregation and dispersion. Our analysis suggests that active tug-of-war processes with loose mechanical coupling can account for several aspects of cargo transport along microtubules in living cells.
Diversity and distribution of chironomids (Diptera, Chironomidae) in pristine Alpine and pre-Alpine springs (Northern Italy)
Valeria LENCIONI,Laura MARZIALI,Bruno ROSSARO
Journal of Limnology , 2011, DOI: 10.4081/jlimnol.2011.s1.106
Abstract: The diversity and distribution of chironomids (Diptera, Chironomidae) were studied in relation to environmental factors in 81 springs under pristine conditions in the Italian Prealps and Alps (Trentino and Veneto, NE-Italy, 46°N, 10-11°E). Each spring was surveyed once, between May and November, in 2005 or in 2007-2008, within 50 m of the spring's source (eucrenal). A total of 173 macroinvertebrate samples were collected, in which 26,871 chironomids (including larvae, pupae, pupal exuviae and adults) were counted. Five subfamilies (Tanypodinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae), 54 genera and 104 species/groups of species were identified. As expected, Orthocladiinae accounted for a large part of specimens (82%), followed by Diamesinae (10%), Chironominae Tanytarsini (6%) and Tanypodinae (2%). Together the Chironominae Chironomini and Prodiamesinae contributed less than 0.05% of the fauna. Larvae represented 97.5% of specimens, mostly juveniles (62.6%). Maximum richness and diversity occurred at intermediate altitudes (ca 900-2100 m a.s.l.). Most taxa were found in a small proportion of sites, and frequencies declined gradually for more widely distributed species. A high number (67%) of rare (= present in less than 10% of sites) taxa were found. Three to 27 taxa were identified per spring. The rheocrene/rheo-helocrene springs were richest in taxa (generally >15 taxa), the mineral spring was poorest, with only three taxa. Most taxa were crenophilous, including lentic, rheobiontic and bryophilous taxa. A Principal Component Analysis (PCA) was performed including 98 taxa. Axes were interpreted calculating the correlation coefficients between site scores and 24 environmental factors. The species with the highest scores were Pseudokiefferiella parva, Corynoneura sp. A, Metriocnemus eurynotus gr., Paratrichocladius skirwithensis and Tvetenia calvescens. Five clusters of sites were identified with K-means analysis on the basis of the first and second PCA axes and a Discriminant Analysis was used to detect environmental factors discriminating the clusters: altitude, canopy cover, hydrological regime, pH, and granulometry as percentage of cobbles and stones. The highly individual nature of springs was highlighted; within the same river basin, between springs and within a single spring. These results suggest that prudent and conservative land management should assume that all springs sheltering such unique faunal assemblages need protection.
Haemodynamics and oxygenation improvement induced by high frequency percussive ventilation in a patient with hypoxia following cardiac surgery: a case report
Alessandro Forti, Valeria Salandin, Paolo Zanatta, Bruno Persi, Carlo Sorbara
Journal of Medical Case Reports , 2010, DOI: 10.1186/1752-1947-4-339
Abstract: A 75-year-old Caucasian man with an ejection fraction of 27 percent, developed a lung infection with severe hypoxaemia [partial pressure of oxygen/fractional inspiratory oxygen of 90] ten days after cardiac surgery. Conventional ventilation did not improve the gas exchange. He was treated with high frequency percussive ventilation for 12 hours with a low conventional respiratory rate (five per minute). His cardiac output and systemic and pulmonary pressures were monitored.Compared to conventional ventilation, high frequency percussive ventilation gives an improvement of the partial pressure of oxygen from 90 to 190 mmHg with the same fractional inspiratory oxygen and positive end expiratory pressure level. His right ventricular stroke work index was lowered from 19 to seven g-m/m2/beat; his pulmonary vascular resistance index from 267 to 190 dynes?seconds/cm5/m2; left ventricular stroke work index from 28 to 16 gm-m/m2/beat; and his pulmonary arterial wedge pressure was lowered from 32 to 24 mmHg with a lower mean airway pressure compared to conventional ventilation. His cardiac index (2.7 L/min/m2) and ejection fraction (27 percent) did not change.Although the high frequency percussive ventilation was started ten days after the conventional ventilation, it still improved the gas exchange. The reduction of right ventricular stroke work index, left ventricular stroke work index, pulmonary vascular resistance index and pulmonary arterial wedge pressure is directly related to the lower respiratory mean airway pressure and the consequent afterload reduction.Lung injury is a well-recognized complication after operations for cardiac surgery [1]. Cardiopulmonary bypass leads to the activation of complement, neutrophils, monocytes, macrophages, platelets and endothelial cells with secretion of cytokines, proteases, arachidonic acid metabolites and oxygen-free radicals. Leukocyte adhesion to microvascular endothelium, leukocyte extravasation and tissue damage can be seen in
A Photogrammetric Method for Stature Estimation: Reliability and Validity
A. De Donno,Santoro Valeria,Morgese Bruno,Introna Francesco
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: The identification of subjects by means of image comparison has already been used in the past; however, the advent of new image elaboration software has provided a new impact and new resources useful for the application of techniques for the identification of the culprits. This study has been carried on at the Department of internal medicine and public health of the University of Bari, Italy, during the year 2011 to investigate the possibility of determining the stature of a subject by means of photogrammetry. Preliminarily, actual heights (in Cm) were obtained by measuring a selection of 288 people including subjects ranging from 150 Cm to 200 Cm with a metallic pole; they were all photographed while standing in a doorway, so as to simulate the images of subjects taken in the doorway of a bank. The selected subjects were measured by a standardized method. The frames obtained were elaborated (by another operator who was unaware of the actual heights) using professional software to determine the height of the people selected using a grid technique. The use of frames for forensic purposes can be considered useful only when the subject is filmed in a static position (i.e., inside the bank doorway). The mean differential values between the actual height and the height measured in people standing, ranging from – 0.90 Cm to + 1.24 Cm, confirm the reliability of the technique. The validity of the technique for the measurement in motion is unreliable, owing to the high variability between the actual heights and the measurements obtained by a professional image editing software (ranging from – 3 Cm to + 6 Cm).
A Modified Soil Quality Index to Assess the Influence of Soil Degradation Processes on Desertification Risk: The Apulia Case
Valeria Ancona,Delia Evelina Bruno,Nicola Lopez,Giuseppe Pappagallo
Italian Journal of Agronomy , 2010, DOI: 10.4081/ija.2010.s3.45
Abstract: Apulia is one of the most prone Italian regions to soil alteration phenomena, due to geographical and climatic conditions and also to human activities’ impact. In this study, in order to investigate regional soil degradation processes, following the “European Directive for Soil Protection”, the ESA’s method has been adopted. It is based on the use of an indicator’s set to assess the desertification risk. This approach simplifies the diagnosis and monitoring of soil degradation processes, defining their status and trend. Special attention has been given to Soil Quality Index (SQI) determined by six predisposing indicators (parent material, soil texture, rock fragment, soil depth, drainage and slope grade). The integration in the SQI calculation of two additional soil parameters (organic matter content and soil salinity) has been considered particularly significant. In fact, through the evaluation of a so “modified SQI” and the Apulia land use too, it could be possible to assess the role of agriculture management on soil degradation processes, which predisposing regional area to desertification threat. Moreover this approach provides short, but accurate, information thanks to GIS integration, which defines phenomena in detail, offering helpful planning tools.
Tools for the development of a benthic quality index for Italian lakes
Bruno ROSSARO,Angela BOGGERO,Valeria LENCIONI,Laura MARZIALI
Journal of Limnology , 2006, DOI: 10.4081/jlimnol.2006.41
Abstract: In this paper, we propose a methodology to develop a benthic quality index useful for Italian lakes. The existing data about benthic macroinvertebrates of the Italian lakes were collected over a period of 50 years, but only a few lakes such as the Maggiore and the Mergozzo have been intensely studied. Some large lakes such as Lake Como are still almost uninvestigated. In total, 570 benthic macroinvertebrate taxa were identified; of which 373 belong to Chironomidae and 85 to Oligochaeta. With the aim of relating environmental variables with macrobenthos assemblages, we carried out a canonical correlation analysis (CANON) using a database that included 1060 sampling points. Both environmental (13 variables describing morphometry and hydrochemistry) and biological data (57 taxa) were available, but only taxa present in at least 10 samples were selected for data analysis. Three canonical variates were ecologically significant. The first one was correlated with conductivity, pH and alkalinity and accounted for 20% of the total variation. The second one was positively correlated with total phosphorus and N-NH4, and inversely with dissolved oxygen, and accounted for 18% of the total variation. The third one showed a direct correlation with maximum lake depth and volume and an inverse correlation with water temperature, and accounted for 17% of the total variation. A Trophic Status Index (TSI), based on the table 11 of the Italian Law 152/99 (without including chlorophyll), was calculated by ranking percent oxygen saturation, transparency and total phosphorus. TSI was used to test a Benthic Quality Index for Italian Lakes (BQIL) which is proposed in the present paper. The algorithm considered three steps. First, the means of three variables were calculated: percent oxygen saturation, transparency and total phosphorus weighted by the taxa abundances. These values are interpreted as optimum for each taxon and used to assign an indicator weight (BQIW). Second, the mean of these three variables was calculated for each taxon (mean BQIW). Third, the mean BQIW was multiplied by taxa abundance and divided by the total number of specimens present at each site for which the BQIL was obtained. Using a regression between BQIL and TSI values, lake sites were assigned to 5 quality classes as required by the Italian Law 152/99 and the WFD 2000/60/CE. This assignment must be considered as tentative, because different lake types should be considered separately to develop an index. At present the lack of information from different lake typologies hinders the development of a mor
Un corpo di donna per fare la guerra. Lettura della Ifigenia in Aulide di Euripide
Valeria Andò
Storia delle Donne , 2009,
Abstract: This paper analyzes Euripides’s Iphigenia in Aulis from a perspective that highlights the relationship between three different levels - the sacred, the political and the private -intersected as they are by the opposition male/female. In the course of the tragedy we assist at the gradual domination of the two spheres of “public” and “political”, while the sphere of “sacred” provides only a ritual frame. On the other hand, from the overall structure of the tragedy it also results that the sphere of “private” relationships and loves is a loser. Iphigenia, who takes upon herself the political and patriotic values of war, peculiar to the male, allows the execution of the sacrificial ritual and hence leads to the apparent triumph of the sacred final. Nevertheless, by resetting the other plans, she attains to upset oppositions and dichotomies and thus questions the prevalence of the sphere of “political” and, paradoxically, even her own reasons. The tragedy not only denounces war and politics as meaningless categories, but even erodes the religious value of sacrifice: in the final part of the tragedy, violence is actually rejected, but the refusal of human sacrifice does not involve a new political tension, and what remains is nothing but the beauty of poetry.
The Second-Agent Effect: Communicative Gestures Increase the Likelihood of Perceiving a Second Agent
Valeria Manera, Marco Del Giudice, Bruno G. Bara, Karl Verfaillie, Cristina Becchio
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0022650
Abstract: Background Beyond providing cues about an agent's intention, communicative actions convey information about the presence of a second agent towards whom the action is directed (second-agent information). In two psychophysical studies we investigated whether the perceptual system makes use of this information to infer the presence of a second agent when dealing with impoverished and/or noisy sensory input. Methodology/Principal Findings Participants observed point-light displays of two agents (A and B) performing separate actions. In the Communicative condition, agent B's action was performed in response to a communicative gesture by agent A. In the Individual condition, agent A's communicative action was replaced with a non-communicative action. Participants performed a simultaneous masking yes-no task, in which they were asked to detect the presence of agent B. In Experiment 1, we investigated whether criterion c was lowered in the Communicative condition compared to the Individual condition, thus reflecting a variation in perceptual expectations. In Experiment 2, we manipulated the congruence between A's communicative gesture and B's response, to ascertain whether the lowering of c in the Communicative condition reflected a truly perceptual effect. Results demonstrate that information extracted from communicative gestures influences the concurrent processing of biological motion by prompting perception of a second agent (second-agent effect). Conclusions/Significance We propose that this finding is best explained within a Bayesian framework, which gives a powerful rationale for the pervasive role of prior expectations in visual perception.
Mechanical Properties of Organelles Driven by Microtubule-Dependent Molecular Motors in Living Cells
Luciana Bruno,Marcelo Salierno,Diana E. Wetzler,Marcelo A. Despósito,Valeria Levi
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018332
Abstract: The organization of the cytoplasm is regulated by molecular motors which transport organelles and other cargoes along cytoskeleton tracks. Melanophores have pigment organelles or melanosomes that move along microtubules toward their minus and plus end by the action of cytoplasmic dynein and kinesin-2, respectively. In this work, we used single particle tracking to characterize the mechanical properties of motor-driven organelles during transport along microtubules. We tracked organelles with high temporal and spatial resolutions and characterized their dynamics perpendicular to the cytoskeleton track. The quantitative analysis of these data showed that the dynamics is due to a spring-like interaction between melanosomes and microtubules in a viscoelastic microenvironment. A model based on a generalized Langevin equation explained these observations and predicted that the stiffness measured for the motor complex acting as a linker between organelles and microtubules is ~ one order smaller than that determined for motor proteins in vitro. This result suggests that other biomolecules involved in the interaction between motors and organelles contribute to the mechanical properties of the motor complex. We hypothesise that the high flexibility observed for the motor linker may be required to improve the efficiency of the transport driven by multiple copies of motor molecules.
Communicative Interactions Improve Visual Detection of Biological Motion
Valeria Manera,Cristina Becchio,Ben Schouten,Bruno G. Bara,Karl Verfaillie
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0014594
Abstract: In the context of interacting activities requiring close-body contact such as fighting or dancing, the actions of one agent can be used to predict the actions of the second agent [1]. In the present study, we investigated whether interpersonal predictive coding extends to interactive activities – such as communicative interactions - in which no physical contingency is implied between the movements of the interacting individuals.
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