1,044 research outputs found
Hydrolyzed protein based materials for biodegradable spray mulching coatings
Low density polyethylene (LDPE) films are widespread used in agriculture
for soil mulching. The use of LDPE mulching films causes the serious drawback of
huge quantities of waste to be disposed of. Over the last years the growing
environmental awareness has been prompting the research to develop a new
generation of mulching products starting with raw materials from renewable origin.
These materials have to retain their physical and mechanical properties while in use
and have to be compostable or biodegradable at the end of their life, degrading via
micro-organisms into carbon dioxide or methane, water and biomass. The research
is focused on the development of novel biodegradable polymeric materials based on
hydrolyzed proteins, derived from waste products of the leather industry.
Biodegradable soil mulching coatings were realized with these biodegradable
polymeric materials by means of spray techniques; the coatings were tested in a
Ligustrum ovalifolium cultivation carried out inside a greenhouse. This paper
describes the functionalities of the new bio-based mulching coatings, which were
developed and tested in real scale greenhouse cultivation tests. During the trial, the
biodegradable soil mulching materials showed suitable properties for an efficient
and profitable use in agriculture. The innovative biodegradable spray coatings
lasted up to 18 months. The biodegradable materials could be the environmentally
friendly alternatives to synthetic petro-chemical polymers and could contribute to a
sustainable agriculture
the effects of control measures on the economic burden associated with epidemics of avian influenza in italy
In 1999, Italy experienced a devastating epidemic of high-pathogenicity avian influenza (HPAI) caused by an H7N1 virus subtype. After this epidemic, a ministerial decree was passed to implement control measures for low-pathogenicity avian influenza (LPAI) due to H5 and H7 subtypes. We investigated whether these control measures have decreased the public expenditure associated with epidemics of LPAI and HPAI by comparing the direct and consequential losses of the 1999 epidemic to the losses associated with successive epidemics. The estimated total economic burden of the epidemics was about euro650 million (euro217 million in direct losses and euro433 million in consequential losses). The 1999 epidemic accounted for most of these losses (euro507 million: euro112 million in direct losses and euro395 million in consequential losses), whereas the total economic burden for the 5 successive LPAI was euro143 million (euro105 million in direct losses and euro38 million in consequential losses). These results demonstrate that the implementation of a coordinated set of disease-control measures, which included both emergency and prophylactic vaccination, was able to reduce the overall costs associated with avian influenza epidemics. The results also show that the application of adequate LPAI control measures may limit the risk of emergence of an HPAI virus in an area with a high poultry density, allowing the complete disruption of the poultry market and its huge associated costs to be avoided
The birthplace and age of the isolated neutron star RX J1856.5-3754
X-ray observations unveiled various types of radio-silent Isolated Neutron
Stars (INSs), phenomenologically very diverse, e.g. the Myr old X-ray Dim INS
(XDINSs) and the kyr old magnetars. Although their phenomenology is much
diverse, the similar periods (P=2--10 s) and magnetic fields (~10^{14} G)
suggest that XDINSs are evolved magnetars, possibly born from similar
populations of supermassive stars. One way to test this hypothesis is to
identify their parental star clusters by extrapolating backward the neutron
star velocity vector in the Galactic potential. By using the information on the
age and space velocity of the XDINS RX J1856.5-3754, we computed backwards its
orbit in the Galactic potential and searched for its parental stellar cluster
by means of a closest approach criterion. We found a very likely association
with the Upper Scorpius OB association, for a neutron star age of 0.42+/-0.08
Myr, a radial velocity V_r^NS =67+/- 13$ km s^{-1}, and a present-time
parallactic distance d_\pi^NS = 123^{+11}_{-15} pc. Our result confirms that
the "true" neutron star age is much lower than the spin-down age (tau_{sd}=3.8
Myrs), and is in good agreement with the cooling age, as computed within
standard cooling scenarios. The mismatch between the spin-down and the
dynamical/cooling age would require either an anomalously large breaking index
(n~20) or a decaying magnetic field with initial value B_0 ~ 10^{14} G.
Unfortunately, owing to the uncertainty on the age of the Upper Scorpius OB
association and the masses of its members we cannot yet draw firm conclusions
on the estimated mass of the RX J1856.5-3754 progenitor.Comment: 6 pages, accepted for publication on Monthly Notices of the Royal
Astronomical Societ
Observations of Isolated Neutron Stars with the ESO Multi-Conjugate Adaptive Optics Demonstrator
High-energy observations have unveiled peculiar classes of isolated neutron
stars which, at variance with radio pulsars, are mostly radio silent and not
powered by the star rotation. Among these objects are the magnetars,
hyper-magnetized neutron stars characterized by transient X-ray/gamma-ray
emission, and neutron stars with purely thermal, and in most cases stationary,
X-ray emission (a.k.a., X-ray dim isolated neutron stars or XDINSs). While
apparently dissimilar in their high-energy behavior and age, both magnetars and
XDINSs have similar periods and unusually high magnetic fields. This suggests a
tantalizing scenario where the former evolve into the latter.Discovering so far
uninvestigated similarities between the multi-wavelength properties of these
two classes would be a further step forward to establish an evolutionary
scenario. A most promising channels is the near infrared (NIR) one, where
magnetars are characterized by a distinctive spectral flattening with respect
to the extrapolation of the soft X-ray spectrum.We observed the two XDINSs RX
J0420.0-5022 and RX J1856.5-3754 with the Multi-Conjugate Adaptive Optics
Demonstrator (MAD) at the Very Large Telescope (VLT) as part of the instrument
guaranteed time observations program, to search for their NIR counterparts.
Both RX J1856.5-3754 and RX J0420.0-5022 were not detected down to K_s ~20 and
Ks ~21.5, respectively. In order to constrain the relation between XDINSs and
magnetars it would be of importance to perform deeper NIR observations. A good
candidate is 1RXS J214303.7+065419 which is the XDINS with the highest inferred
magnetic field.Comment: Accepted for publication in Astronomy and Astrophysic
Characteristics of Submucous Myomas and the Risk of Anemia
Background and Objectives: Uterine fibroids still represent the most common indication for hysterectomy for benign pathologies. In the United States, more than 479,000 hysterectomies are performed annually, 46.6% for myomas and 47.7% in women aged from 18 to 44 years. By applying appropriateness criteria to this procedure, it has been estimated that overuse ranges from 16 to 70%. One of the main reasons that induce patients and gynecologists to consider hysterectomy is represented by severe anemia. Materials and Methods: This is a retrospective cohort study of 202 patients with uterine fibroids diagnosed by transvaginal ultrasound who underwent a hysteroscopic procedure. Myoma grade, size, location, and number were assessed by transvaginal scan and office hysteroscopy and correlated to the pre-treatment hemoglobin level. Results: Univariate analysis showed that anemia does not have a statistically significant association with myoma number and with age considered as a numerical predictor. In the patients with myoma type 0, there is a possibility of 81% having anemia regardless of menorrhagia. On the contrary, in patients with myoma type 1 or type 2, the possibility of having anemia varies according to the presence or absence of menorrhagia. If there is menorrhagia, the risk of moderate anemia is only present for myomas >60 mm. Conclusions: The results of this study may contribute to defining objective criteria for the management of submucous myomas and anemia. Our data suggest that submucosal myomas type 0 >10 mm should always be treated, putting patients at risk for anemia. Myomas type 2 and 3 should be treated for the risk of anemia in the presence of menorrhagia episodes or if > of 60 mm. Adequate management of anemia and myomas could reduce the rate of unnecessary hysterectomies
Bayesian inference in dynamic models with latent factors
In time series analysis, latent factors are often introduced to model the heterogeneous time evolution of the observed process. The presence of unobserved components makes the maximum likelihood estimation method more difficult to apply. Thus a Bayesian approach is sometimes preferable since it allows to treat general state space models and makes easier the simulation based approach to parameters estimation and latent factors filtering. The paper examines economic time series models in a Bayesian perspective focusing, through some examples, on the extraction of the Business Cycle components like cycle and trend. We briefly review some general univariate and multivariate Bayesian dynamic models and discuss the simulation based techniques, such as Gibbs sampling, adaptive importance sampling and particle filter, useful for parameter estimation and latent factor extraction
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