1,760 research outputs found
L’esilio e la frontiera nell’italianità letteraria
Full Article in ItalianOriginally, exile was a punishment implying a permanent or temporary banishment from homeland. In modern times as it was not regarded as a penalty anymore, it turned into a self-imposed, voluntary, castigation. In this paper, the main characteristics and consequences of exile is examined from the Italian point of view, notwithstanding the historical events which led to the unification of Italy in a state. The parameters upon which ‘Italianity’ has been predicated are constituted both by language and literature, which – contrary to many European nations (where the national history intertwines with the literary and cultural history) – have paradoxically developed as foreign to any idea of state and/or political entity
Letter to the editor: autoimmune pathogenic mechanisms in amyotrophic lateral sclerosis
The innate immune system may affect the function and survival of motor neurons in ALS by at least three mechanisms. First, there is evidence to suggest that aggregates of mutant SOD1—which is derived from microglial and astroglial cells—activate neighbouring microglia by binding to TLR2, TLR4, and CD14, and subsequently promote neuronal cell death [9]. Second, the release of pro- inflammatory cytokines may drive motor neuron damage. Third, although poorly understood, a mechanism has been suggested on the basis of the functional analysis of microglial cells that express mutant SOD1 [10]. These cells showed impaired overall motility and a reduced capacity to clear neuronal cell debris. Impairment of microglial cell phagocytosis may therefore contribute to the accumulation of further immunostimulatory proteins, including mutant SOD1, chromogranin A, and dsRNA, thereby resulting in disease progression
Letter to the editor: autoimmune pathogenic mechanisms in Huntington’s disease
Letter to the Editor: Autoimmune pathogenic mechanisms in Huntington's disease
Tracheocutaneous fistula in patients undergoing supracricoid partial laryngectomy: the role of chronic aspiration
The aim of the present retrospective controlled study was to analyse and compare risk factors for tracheocutaneous fistula in patients who received tracheostomy after supracricoid partial laryngectomy with those who received tracheostomy for other causes. We enrolled 39 patients with tracheocutaneous fistulas who were divided into two groups. The first received temporary tracheostomy for supracricoid partial laryngectomies (n = 21), while the control group consisted of patients who received temporary tracheostomy for other causes (n = 18). Risk factors believed to play a role in the pathogenesis of tracheocutaneous fistula were examined including advanced age, cardiopathy, local infections, radiotherapy, elevated body mass index, malnutrition, decannulation time and aspiration grade. The Leipzig and Pearson scale score was significantly higher in the supracricoid partial laryngectomy group (p = 0.006 and 0.031 for univariate and multivariate analyses, respectively). The penetration/aspiration scale score was significantly higher in the supracricoid partial laryngectomy group as determined by univariate analysis (p = 0.014). The decannulation time was significantly lower in the supracricoid partial laryngectomy group (p = 0.004 and 0.0004 for univariate and multivariate analyses, respectively). The number of surgical closures for tracheocutaneous fistula was significantly higher in the supracricoid partial laryngectomy group by univariate analysis (p = 0.027). These results suggest that chronic aspiration and related cough may be important pathogenic factors for tracheocutaneous fistula and could be responsible for the significantly higher rates of closure failure in patients after supracricoid partial laryngectomy
Comparative microbiomics of tephritid frugivorous pests (Diptera : Tephritidae) from the field : a tale of high variability across and within species
The family Tephritidae includes some of the most notorious insect pests of agricultural and horticultural crops in tropical and sub-tropical regions. Despite the interest in the study of their gut microbiome, our present knowledge is largely based on the analysis of laboratory strains. In this study, we present a first comparative analysis of the gut microbiome profiles of field populations of ten African and Mediterranean tephritid pests. For each species, third instar larvae were sampled from different locations and host fruits and compared using 16S rRNA amplicon sequencing and a multi-factorial sampling design. We observed considerable variation in gut microbiome diversity and composition both between and within fruit fly species. A "core" microbiome, shared across all targeted species, could only be identified at most at family level (Enterobacteriaceae). At genus level only a few bacterial genera (Klebsiella,Enterobacter, andBacillus) were present in most, but not all, samples, with high variability in their relative abundance. Higher relative abundances were found for seven bacterial genera in five of the fruit fly species considered. These wereErwiniainBactrocera oleae,LactococcusinB. zonata,ProvidenciainCeratitis flexuosa,Klebsiella, andRahnellainC. podocarpiandAcetobacterandSerratiainC. rosa. With the possible exception ofC. capitataandB. dorsalis(the two most polyphagous species considered) we could not detect obvious relationships between fruit fly dietary breadth and microbiome diversity or abundance patterns. Similarly, our results did not suggest straightforward differences between the microbiome profiles of species belonging to Ceratitisand the closely relatedBactrocera/Zeugodacus. These results provide a first comparative analysis of the gut microbiomes of field populations of multiple economically relevant tephritids and provide base line information for future studies that will further investigate the possible functional role of the observed associations
Spin-dependent direct gap emission in tensile-strained Ge films on Si substrates
The circular polarization of direct gap emission of Ge is studied in
optically-excited tensile-strained Ge-on-Si heterostructures as a function of
doping and temperature. Owing to the spin-dependent optical selection rules,
the radiative recombinations involving strain-split light (cG-LH) and heavy
hole (cG-HH) bands are unambiguously resolved. The fundamental cG-LH transition
is found to have a low temperature circular polarization degree of about 85%
despite an off-resonance excitation of more than 300 meV. By photoluminescence
(PL) measurements and tight binding calculations we show that this
exceptionally high value is due to the peculiar energy dependence of the
optically-induced electron spin population. Finally, our observation of the
direct gap doublet clarifies that the light hole contribution, previously
considered to be negligible, can dominate the room temperature PL even at low
tensile strain values of about 0.2%
A review of the current knowledge on Zeugodacus cucurbitae (Coquillett) (Diptera, Tephritidae) in Africa, with a list of species included in Zeugodacus
Published online 2015 Nov 26This paper reviews all available information regarding the occurrence and biology of the melon fly, Zeugodacus cucurbitae (Coquillett), in the Afrotropical Region, including data on invasion history, distribution patterns, population genetics, host range, and interspecific competition. Although limited intraspecific variability has been observed within the region regarding the above mentioned aspects, there seems to be no indication that Zeugodacus cucurbitae represents a species complex. A checklist of all of the species included in Zeugodacus as recently proposed by Virgilio et al. (2015) is provided
DNA Barcoding to Improve the Taxonomy of the Afrotropical Hoverflies (Insecta: Diptera: Syrphidae)
The identification of Afrotropical hoverflies is very difficult because of limited recent taxonomic revisions and the lack of comprehensive identification keys. In order to assist in their identification, and to improve the taxonomy of this group, we constructed a reference dataset of 513 COI barcodes of 90 of the more common nominal species from Ghana, Togo, Benin and Nigeria (W Africa) and added ten publically available COI barcodes from nine nominal Afrotropical species to this (total: 523 COI barcodes; 98 nominal species; 26 genera). The identification accuracy of this dataset was evaluated with three methods (K2P distance-based, Neighbor-Joining (NJ) / Maximum Likelihood (ML) analysis, and using SpeciesIdentifier). Results of the three methods were highly congruent and showed a high identification success. Nine species pairs showed a low ( 0.03) maximum intraspecific K2P distance was observed in eight species and barcodes of these species not always formed single clusters in the NJ / ML analayses which may indicate the occurrence of cryptic species. Optimal K2P thresholds to differentiate intra- from interspecific K2P divergence were highly different among the three subfamilies (Eristalinae: 0.037, Syrphinae: 0.06, Microdontinae: 0.007–0.02), and among the different general suggesting that optimal thresholds are better defined at the genus level. In addition to providing an alternative identification tool, our study indicates that DNA barcoding improves the taxonomy of Afrotropical hoverflies by selecting (groups of) taxa that deserve further taxonomic study, and by attributing the unknown sex to species for which only one of the sexes is known
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