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How does the mite Varroa destructor kill the honeybee Apis mellifera? Alteration of cuticular hydrcarbons and water loss in infested honeybees.
No full textSeveral factors threaten the health of honeybees; among them the parasitic mite Varroa destructor and the Deformed Wing Virus play a major role. Recently, the dangerous interplay between the mite and the virus was studied in detail and the transition, triggered by mite feeding, from a benign covert infection to a devastating viral outbreak, characterized by an intense viral replication, associated with some characteristic symptoms, was described. In order to gain insight into the events preceding that crucial transition we carried out standardized lab experiments aiming at studying the effects of parasitization in asymptomatic bees to establish a relationship between such effects and bee mortality. It appears that parasitization alters the capacity of the honeybee to regulate water exchange; this, in turn, has severe effects on bee survival.
Journal of Insect Physiology
Available online 3 October 2012
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How does the mite Varroa destructor kill the honeybee Apis mellifera? Alteration of cuticular hydrcarbons and water loss in infested honeybees
* Desiderato Annoscia,
* Fabio Del Piccolo,
* Francesco NazziCorresponding author contact information, E-mail the corresponding author
* Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Udine, Via delle Scienze 208, 33100 Udine, Italy
Received 24 May 2012
Revised 20 September 2012
Accepted 22 September 2012
Available online 3 October 2012
* http://dx.doi.org/10.1016/j.jinsphys.2012.09.008, How to Cite or Link Using DOI
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Abstract
Several factors threaten the health of honeybees; among them the parasitic mite Varroa destructor and the Deformed Wing Virus play a major role. Recently, the dangerous interplay between the mite and the virus was studied in detail and the transition, triggered by mite feeding, from a benign covert infection to a devastating viral outbreak, characterized by an intense viral replication, associated with some characteristic symptoms, was described. In order to gain insight into the events preceding that crucial transition we carried out standardized lab experiments aiming at studying the effects of parasitization in asymptomatic bees to establish a relationship between such effects and bee mortality. It appears that parasitization alters the capacity of the honeybee to regulate water exchange; this, in turn, has severe effects on bee survival.
These results are discussed in light of possible novel strategies aiming at mitigating the impact of the parasite on honeybee health
Central nervous system alterations in cirrhosis: the role of portal-systemic shunt and portal hypoperfusion
No full textThe role of portal-systemic shunting and portal liver hypoperfusion in the pathophysiology of central nervous system dysfunction (CNSD) of cirrhosis is not yet well defined. It is well known that one of the most important collateral vessels (CVs) is a patent paraumbilical vein (PUV), but there is controversy regarding its clinical significance. We have evaluated the relationships between neuropsychological and EEG alterations, ammonia plasma level (NH4), hepatic function, and portal hemodynamics (Doppler Ultrasound) in 95 cirrhotic patients. Patency, diameter, or flow of PUV or the presence of other CVs were not related to an increased prevalence of neuropsychological or EEG abnormalities. Patients with effective portal flow (EPF = portal flow - PUV flow) lower than 692 mL/min (median) had a significantly higher risk of failing the neuropsychological test, or of having an altered EEG. Low EPF and prothrombin time (<50%), and high NH4 (51 micromol/L) were independent predictors of an abnormal EEG. Considering both low EPF and the numerosity of CVs, only low EPF was found to explain EEG alterations. In conclusion, portal liver hypoperfusion and decreased liver function were associated with an increased risk of CNSD in cirrhotic patients, whereas PUV patency per se was not
Motor impairment in patients with minimal hepatic encephalopathy evaluated by the Lateralized Readiness Potential
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Central Nervous system alterations in liver cirrhosis: the role of portal-systemic shunt and portal hypoperfusion. 18 (1), 51-62
No full textThe role of portal-systemic shunting and portal liver hypoperfusion in the pathophysiology of central nervous system dysfunction (CNSD) of cirrhosis is not yet well defined. It is well known that one of the most important collateral vessels (CVs) is a patent paraumbilical vein (PUV), but there is controversy regarding its clinical significance. We have evaluated the relationships between neuropsychological and EEG alterations, ammonia plasma level (NH4), hepatic function, and portal hemodynamics (Doppler Ultrasound) in 95 cirrhotic patients. Patency, diameter, or flow of PUV or the presence of other CVs were not related to an increased prevalence of neuropsychological or EEG abnormalities. Patients with effective portal flow (EPF = portal flow - PUV flow) lower than 692 mL/min (median) had a significantly higher risk of failing the neuropsychological test, or of having an altered EEG. Low EPF and prothrombin time (<50%), and high NH4 (51 micromol/L) were independent predictors of an abnormal EEG. Considering both low EPF and the numerosity of CVs, only low EPF was found to explain EEG alterations. In conclusion, portal liver hypoperfusion and decreased liver function were associated with an increased risk of CNSD in cirrhotic patients, whereas PUV patency per se was not
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