4,937 research outputs found
Determinants of the population growth of the West Nile virus mosquito vector Culex pipiens in a repeatedly affected area in Italy
Background
The recent spread of West Nile Virus in temperate countries has raised concern. Predicting the likelihood of transmission is crucial to ascertain the threat to Public and Veterinary Health. However, accurate models of West Nile Virus (WNV) expansion in Europe may be hampered by limited understanding of the population dynamics of their primary mosquito vectors and their response to environmental changes.<p></p>
Methods
We used data collected in north-eastern Italy (2009–2011) to analyze the determinants of the population growth rate of the primary WNV vector Culex pipiens. A series of alternative growth models were fitted to longitudinal data on mosquito abundance to evaluate the strength of evidence for regulation by intrinsic density-dependent and/or extrinsic environmental factors. Model-averaging algorithms were then used to estimate the relative importance of intrinsic and extrinsic variables in describing the variations of per-capita growth rates.<p></p>
Results
Results indicate a much greater contribution of density-dependence in regulating vector population growth rates than of any environmental factor on its own. Analysis of an average model of Cx. pipiens growth revealed that the most significant predictors of their population dynamics was the length of daylight, estimated population size and temperature conditions in the 15 day period prior to sampling. Other extrinsic variables (including measures of precipitation, number of rainy days, and humidity) had only a minor influence on Cx. pipiens growth rates.<p></p>
Conclusions
These results indicate the need to incorporate density dependence in combination with key environmental factors for robust prediction of Cx. pipiens population expansion and WNV transmission risk. We hypothesize that detailed analysis of the determinants of mosquito vector growth rate as conducted here can help identify when and where an increase in vector population size and associated WNV transmission risk should be expected.<p></p>
Automorphisms of the affine SU(3) fusion rules
We classify the automorphisms of the (chiral) level-k affine SU(3) fusion
rules, for any value of k, by looking for all permutations that commute with
the modular matrices S and T. This can be done by using the arithmetic of the
cyclotomic extensions where the problem is naturally posed. When k is divisible
by 3, the automorphism group (Z_2) is generated by the charge conjugation C. If
k is not divisible by 3, the automorphism group (Z_2 x Z_2) is generated by C
and the Altsch\"uler--Lacki--Zaugg automorphism. Although the combinatorial
analysis can become more involved, the techniques used here for SU(3) can be
applied to other algebras.Comment: 21 pages, plain TeX, DIAS-STP-92-4
Fe Ka line emission from the Arches cluster region - evidence for ongoing particle bombardment?
We present the results of eight years of XMM-Newton observations of the
region surrounding the Arches cluster in the Galactic Center. We study the
spatial distribution and temporal behaviour of the Fe-Ka line emission with the
objective of identifying the likely source of the excitation. We investigate
the variability of the 6.4-keV line emission of four clouds through spectral
fitting of the EPIC MOS data with the use of a modelled background, which
avoids many of the systematics inherent in local background subtraction. We
also employ spectral stacking of both EPIC PN and MOS data to search for
evidence of an Fe-K edge feature imprinted on the underlying X-ray continuum.
The lightcurves of the Fe-Ka line from three bright molecular knots close to
the Arches cluster are found to be constant over the 8-year observation window.
West of the cluster, however, we found a bright cloud exhibiting the fastest
Fe-Ka variability yet seen in a molecular cloud in the Galactic Center region.
The time-averaged spectra of the molecular clouds reveal no convincing evidence
of the 7.1-keV edge feature. The EW of the 6.4-keV line emitted by the clouds
near the cluster is found to be ~1.0 keV. The observed Fe-Ka line flux and the
high EW suggest the fluorescence has a photoionization origin, although
excitation by cosmic-ray particles is not specifically excluded. For the three
clouds nearest to the cluster, an identification of the source of
photo-ionizing photons with an earlier outburst of Sgr A* is however at best
tentative. The hardness of the nonthermal component associated with the 6.4-keV
line emission might be best explained in terms of bombardment by cosmic-ray
particles from the Arches cluster itself. The relatively short-timescale
variability seen in the 6.4-keV line emission from the cloud to the West of the
cluster is most likely the result of illumination by a nearby transient X-ray
source.Comment: 13 pages, 6 figures, accepted for publication in Astronomy and
Astrophysic
Effectiveness of the spot-on combination of moxidectin and imidacloprid (Advocate®) in the treatment of ocular thelaziosis by Thelazia callipaeda in naturally infected cats
Background: The present study evaluated the therapeutic effectiveness of moxidectin 1.0% (w/v) and imidacloprid 10% (w/v) (Advocate® spot-on solution for cats, Bayer Animal Health) against natural infections with the eyeworm Thelazia callipaeda in cats. This study was conducted as a GCP, negative-controlled, blinded and randomised field study in privately owned cats living in an area in southern Italy where T. callipaeda is enzootic. Methods: The study was carried out in 30 cats (19 females and 11 males, aged from 8 months to 5 years, weighing 1.2-5.2 kg) of different breeds, naturally infected by T. callipaeda. At study inclusion (Day 0), animals were physically examined and the infection level was assessed by examination of both eyes for clinical score and live adult T. callipaeda count. Each cat was weighed and randomly assigned to one of the treatment groups (G1: Advocate, G2: untreated control). Clinical assessments and T. callipaeda adult counts were performed on Day 14. At the study completion visit on Day 28, clinical assessments and counts of T. callipaeda adults and larvae were performed. All cats were daily observed by their owners and general health conditions were recorded during the entire period of the study. Results: The primary effectiveness variable was the percentage of animals in G1 group (Advocate) showing a complete elimination (parasitological cure) of adult eye worms at Day 14 and Day 28. The effectiveness of the treatment in the G1 group was 93.3 and 100% at Day 14 and Day 28, respectively, when compared to group G2. Total worm count reduction from both eyes for Advocate was 96.3% on Day 14 and 100% on Day 28. Clinical data were confirmed by the examination of conjunctival pouch flushing. An overall reduction in the number of cats with lacrimation and conjunctivitis was observed following treatment despite the fact that in a few cats treated with Advocate clinical signs persisted due to the chronic nature of the disease. Conclusions: Based on the results of the present trial, a single dose of Advocate was found to be safe and highly effective in the treatment of natural T. callipaeda infection in cats
Hunting for the New Symmetries in Calabi-Yau Jungles
It was proposed that the Calabi-Yau geometry can be intrinsically connected
with some new symmetries, some new algebras. In order to do this it has been
analyzed the graphs constructed from K3-fibre CY_d (d \geq 3) reflexive
polyhedra. The graphs can be naturally get in the frames of Universal
Calabi-Yau algebra (UCYA) and may be decode by universal way with changing of
some restrictions on the generalized Cartan matrices associated with the Dynkin
diagrams that characterize affine Kac-Moody algebras. We propose that these new
Berger graphs can be directly connected with the generalizations of Lie and
Kac-Moody algebras.Comment: 29 pages, 15 figure
Intravesical electromotive mitomycin C versus passive transport mitomycin C for high risk superficial bladder cancer: a prospective randomized study.
PURPOSE: In laboratory studies electromotive mitomycin C (MMC) demonstrated markedly increased transport rates compared with passive transport. We performed a prospective study in patients with high risk superficial bladder cancer to assess the efficacy of intravesical electromotive vs passive MMC using bacillus Calmette-Guerin (BCG) as a comparative treatment.
MATERIALS AND METHODS: Following transurethral resection and multiple biopsies 108 patients with multifocal Tis, including 98 with T1 tumors, were randomized into 3 equal groups of 36 each who underwent 40 mg electromotive MMC instillation with 20 mA electric current for 30 minutes, 40 mg passive MMC with a dwell time of 60 minutes or 81 mg BCG with a dwell time of 120 minutes. Patients were scheduled for an initial 6 weekly treatments, a further 6 weekly treatments for nonresponders and a followup 10 monthly treatments for responders. Primary end points were the complete response rate at 3 and 6 months. MMC pharmacokinetics were assessed.
RESULTS: The complete response for electromotive vs passive MMC at 3 and 6 months was 53% versus 28% (p = 0.036) and 58% versus 31% (p = 0.012). For BCG the responses were 56% and 64%. Median time to recurrence was 35 vs 19.5 months (p = 0.013) and for BCG it was 26 months. Peak plasma MMC was significantly higher following electromotive MMC than after MMC (43 vs 8 ng/ml), consistent with bladder content absorption.
CONCLUSIONS: Intravesical electromotive administration increases bladder uptake of MMC, resulting in an improved response rate in cases of high risk superficial bladder cancer
Intravesical oxybutynin: mode of action assessed by passive diffusion and electromotive administration with pharmacokinetics of oxybutynin and N-desethyl oxybutynin.
PURPOSE: A proportion of patients with detrusor hyperreflexia who are unresponsive to oral oxybutynin often benefit from intravesical oxybutynin instillation. To our knowledge the precise mode of action of this method is obscure.
MATERIALS AND METHODS: In 12 patients with detrusor hyperreflexia who were previously unresponsive to oral and intravesical passive diffusion of 5 mg. oxybutynin we administered 5 mg. oxybutynin orally as well as increased doses of 15 mg. oxybutynin intravesically with passive diffusion and with 15 mA. associated electric current. Each administration mode per patient was associated with an 8-hour urodynamic monitoring session during which oxybutynin and N-desethyl oxybutynin plasma levels, and intravesical oxybutynin uptake were measured.
RESULTS: A dose of 5 mg. oxybutynin orally induced no urodynamic improvement with an area under the plasma concentration time curve of combined N-desethyl oxybutynin plus oxybutynin of 16,297 ng./8 hours and an area under the curve ratio of N-desethyl oxybutynin-to-oxybutynin of 11:1. Passive diffusion oxybutynin resulted in 12 mg. oxybutynin intravesical uptake and significant improvement in 3 of 8 urodynamic measurements, although the area under the curve of combined N-desethyl oxybutynin plus oxybutynin was only 2,123 ng./8 hours and the N-desethyl oxybutynin-to-oxybutynin ratio was 1.1:1.0. Electromotive administration of oxybutynin resulted in almost complete intravesical uptake of the 15 mg. dose, significant improvement in all 8 urodynamic measurements and an increased oxybutynin level versus oral and passive diffusion, although the area under the curve of combined N-desethyl oxybutynin plus oxybutynin was 4,574 ng./8 hours and the N-desethyl oxybutynin-to-oxybutynin ratio was inverted at 1.0:1.4. The oral dose of 5 mg. oxybutynin caused anticholinergic side effects in 8 of the 12 patients. Neither intravesical passive diffusion nor electromotive administration caused side effects with an uptake of 12 and 15 mg., respectively.
CONCLUSIONS: A large proportion of intravesical oxybutynin is sequestered, probably in the urothelium. Intravesical oxybutynin administration confers therapeutic benefits via localized direct action within the bladder wall.
Comment in
Intravesical treatment of bladder dysfunction. [J Urol. 2001
Scintillating double beta decay bolometers
We present the results obtained in the development of scintillating Double
Beta Decay bolometers. Several Mo and Cd based crystals were tested with the
bolometric technique. The scintillation light was measured through a second
independent bolometer. A 140 g CdWO_4 crystal was run in a 417 h live time
measurement. Thanks to the scintillation light, the alpha background is easily
discriminated resulting in zero counts above the 2615 keV gamma line of
Thallium 208. These results, combined with an extremely easy light detector
operation, represent the first tangible proof demonstrating the feasibility of
this kind of technique.Comment: 15 pages, 8 figure
The X-ray lightcurve of Sgr A* over the past 150 years inferred from Fe-Ka line reverberation in Galactic Centre molecular clouds
We examine the temporal and spectral properties of nine Fe-Ka bright
molecular clouds within about 30 pc of Sgr A*, in order to understand and
constrain the primary energising source of the Fe fluorescence. Significant
Fe-Ka variability was detected, with a spatial and temporal pattern consistent
with that reported in previous studies. The main breakthrough that sets our
paper apart from earlier contributions on this topic is the direct measurement
of the column density and the Fe abundance of the MCs in our sample. We used
the EW measurements to infer the average Fe abundance within the clouds to be
1.60.1 times solar. The cloud column densities derived from the spectral
analysis were typically of the order of 10 cm, which is
significantly higher than previous estimates. This in turn has a significant
impact on the inferred geometry and time delays within the cloud system. Past
X-ray activity of Sgr A* is the most likely source of ionisation within the
molecular clouds in the innermost 30 pc of the Galaxy. In this scenario, the
X-ray luminosity required to excite these reflection nebulae is of the order of
10 erg s, significantly lower than that estimated for the
Sgr B2 molecular cloud. Moreover, the inferred Sgr A* lightcurve over the past
150 years shows a long-term downwards trend punctuated by occasional
counter-trend brightening episodes of at least 5 years duration. Finally, we
found that contributions to the Fe fluorescence by X-ray transient binaries and
cosmic-ray bombardment are very likely, and suggest possible ways to study this
latter phenomenon in the near future.Comment: 23 pages, 14 figures, accepted for publication in Astronomy &
Astrophysic
EU-NICE, Eurasian University Network for International Cooperation in Earthquakes
Despite the remarkable scientific advancements of earthquake engineering and seismology in many countries,
seismic risk is still growing at a high rate in the world’s most vulnerable communities. Successful practices have shown that a community’s capacity to manage and reduce its seismic risk relies on capitalization on policies, on
technology and research results. An important role is played by education, than contribute to strengthening
technical curricula of future practitioners and researchers through university and higher education programmes.
In recent years an increasing number of initiatives have been launched in this field at the international and global
cooperation level. Cooperative international academic research and training is key to reducing the gap between
advanced and more vulnerable regions. EU-NICE is a European Commission funded higher education
partnership for international development cooperation with the objective to build capacity of individuals who
will operate at institutions located in seismic prone Asian Countries. The project involves five European
Universities, eight Asian universities and four associations and NGOs active in advanced research on seismic
mitigation, disaster risk management and international development.
The project consists of a comprehensive mobility scheme open to nationals from Afghanistan, Bangladesh,
China, Nepal, Pakistan, Thailand, Bhutan, India, Indonesia, Malaysia, Maldives, North Korea, Philippines, and
Sri Lanka who plan to enrol in school or conduct research at one of five European partner universities in Italy,
Greece and Portugal. During the 2010-14 time span a total number of 104 mobilities are being involved in
scientific activities at the undergraduate, masters, PhD, postdoctoral and academic-staff exchange levels.
This high number of mobilities and activities is selected and designed so as to produce an overall increase of
knowledge that can result in an impact on earthquake mitigation. Researchers, future policymakers and
practitioners build up their curricula over a range of disciplines in the fields of engineering, seismology, disaster
risk management and urban planning. Specific educational and research activities focus on earthquake risk
mitigation related topics such as: anti-seismic structural design, structural engineering, advanced computer
structural collapse analysis, seismology, experimental laboratory studies, international and development issues in
disaster risk management, social-economical impact studies, international relations and conflict resolution
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