273 research outputs found
Infrastructure Vulnerability Index of drinking water systems to terrorist attacks
Drinking water supply systems are vulnerable targets for which counter-terrorism measures have been raised worldwide. The threat of terrorist attacks to these systems has led to the need for the international scientific community to deal with the vulnerability assessment related to such events. In this context, this paper proposes an Infrastructure Vulnerability Index for drinking water distribution system with the aim of providing managers with a tool to assess system vulnerability to possible terrorist acts and to support the investments choice aimed at increasing security. This index is obtained using a set of indicators with reference to the structural parts of the system and considers both intentional contamination and physical damage. The index uses a hierarchic structure and decomposes the system into components and uses the Analytic Hierarchy Process to compute the weights. An application of the index was carried out for three water schemes of the Province of Crotone (Southern Italy) and the results obtained allowed to highlight the characteristics of the index and its usefulness
Sustainable Water Management Index,SWaM_Index
The present paper describes the Sustainable Water Management Index, SWaM_Index, useful for managers to measure the sustainability of water management and to assess the effects of the policies undertaken in the direction of sustainability. The structure of the proposed index has been derived from European legal framework of the water resources sector, and the index is obtained from elementary indicators of environmental, economic, social and institutional nature, subsequently aggregated in sub-themes, themes and pillars. The index is well applicable on a national, regional but also local scale and the sustainable management of water resources is assessed considering natural systems, artificial systems and socio-economic and institutional aspects
Spitzer-IRAC survey of molecular jets in Vela-D
We present a survey of H2 jets from young protostars in the Vela-D molecular
cloud (VMR-D), based on Spitzer -IRAC data between 3.6 and 8.0 micron. Our
search has led to the identification of 15 jets and about 70 well aligned knots
within 1.2 squared degree. We compare the IRAC maps with observations of the H2
1-0 S(1) line at 2.12 micron, with a Spitzer-MIPS map at 24 and 70 micron, and
with a map of the dust continuum emission at 1.2 mm. We find a association
between molecular jets and dust peaks. The jet candidate exciting sources have
been searched for in the published catalog of the Young Stellar Objects of
VMR-D. We selected all the sources of Class II or earlier which are located
close to the jet center and aligned with it.The association between jet and
exciting source was validated by estimating the differential extinction between
the jet opposite lobes. We are able to find a best-candidate exciting source in
all but two jets. Four exciting sources are not (or very barely) observed at
wavelengths shorter than 24 micron, suggesting they are very young protostars.
Three of them are also associated with the most compact jets. The exciting
source Spectral Energy Distributions have been modeled by means of the
photometric data between 1.2 micron and 1.2 mm. From SEDs fits we derive the
main source parameters, which indicate that most of them are low-mass
protostars. A significant correlation is found between the projected jet length
and the [24] - [70] color, which is consistent with an evolutionary scenario
according to which shorter jets are associated with younger sources. A rough
correlation is found between IRAC line cooling and exciting source bolometric
luminosity, in agreement with the previous literature. The emerging trend
suggests that mass loss and mass accretion are tightly related phenomena and
that both decrease with time.Comment: Accepted by The Astrophysical Journa
On the outcome in stroke patients one year later: the role of atrial fibrillation
The post-stroke aftermath of patients suffering from atrial fibrillation (AF) is investigated. A total of 104 consecutive patients (80 with AF and 24 without AF) were referred to a rehabilitation centre and enrolled. They underwent a rehabilitative programme. Disability was assessed by using the Functional Independence Measure (FIM), at the time of admission, discharge and after 1 year. Death was more frequent over the 1-year interval in AF group. Ten patients died (42%), whereas in the non-AF group death occurred in 15 cases (19%). By using chi-square test, the difference was significant (P < 0.02). The logistic regression analysis indicated that the unique variable affecting the FIM at follow-up was the FIM at discharge (P < 0.0001). AF was not a significant variable in the equation. The result can be attributed to subject attrition in the AF group, as the most severe patients died and survivors could benefit from a better functional status
Nanoliter contact angle probes tumor angiogenic ligand-receptor protein interactions
Any molecular recognition reaction supported by a solid-phase drives a specific change of the solid-solution interfacial tension. Sessile Contact Angle (CA) experiments can be readily used to track this thermodynamic parameter, prompting this well-known technique to be reinvented as an alternative, easy-access and label-free way to probe and study molecular recognition events.
Here we deploy this technique, renamed for this application CONAMORE (CONtact Angle MOlecular REcognition), to study the interaction of the tumor-derived pro-angiogenic vascular endothelial growth factor-A (VEGF-A) with the extracellular domain of its receptor VEGFR2. We show that CONAMORE recognizes the high affinity binding of VEGF-A at nanomolar concentrations to surface-immobilized VEGFR2 regardless of the presence of a ten folds excess of a non specific interacting protein, and that it further proofs its specificity and reliability on competitive binding experiments involving neutralizing anti-VEGF-A antibodies. Finally, CONAMORE shows the outstanding capability to detect the specific interaction between VEGFR2 and low molecular weight ligands, such as Cyclo-VEGI, a VEGFR2 antagonist cyclo-peptide, that weights about 2 kDa
Optical properties of highly n-doped germanium obtained by in situ doping and laser annealing
High n-type doping in germanium is essential for many electronic and optoelectronic applications especially for high performance Ohmic contacts, lasing and mid-infrared plasmonics. We report on the combination of in situ doping and excimer laser annealing to improve the activation of phosphorous in germanium. An activated n-doping concentration of 8.8  ×  1019 cm−3 has been achieved starting from an incorporated phosphorous concentration of 1.1  ×  1020 cm−3. Infrared reflectivity data fitted with a multi-layer Drude model indicate good uniformity over a 350 nm thick layer. Photoluminescence demonstrates clear bandgap narrowing and an increased ratio of direct to indirect bandgap emission confirming the high doping densities achieved
The YSO Population in the Vela-D Molecular Cloud
We investigate the young stellar population in the Vela Molecular Ridge,
Cloud-D (VMR-D), a star forming (SF) region observed by both Spitzer/NASA and
Herschel/ESA space telescope. The point source, band-merged, Spitzer-IRAC
catalog complemented with MIPS photometry previously obtained is used to search
for candidate young stellar objects (YSO), also including sources detected in
less than four IRAC bands. Bona fide YSO are selected by using appropriate
color-color and color-magnitude criteria aimed to exclude both Galatic and
extragalactic contaminants. The derived star formation rate and efficiency are
compared with the same quantities characterizing other SF clouds. Additional
photometric data, spanning from the near-IR to the submillimeter, are used to
evaluate both bolometric luminosity and temperature for 33 YSOs located in a
region of the cloud observed by both Spitzer and Herschel. The
luminosity-temperature diagram suggests that some of these sources are
representative of Class 0 objects with bolometric temperatures below 70 K and
luminosities of the order of the solar luminosity. Far IR observations from the
Herschel/Hi-GAL key project for a survey of the Galactic plane are also used to
obtain a band-merged photometric catalog of Herschel sources aimed to
independently search for protostars. We find 122 Herschel cores located on the
molecular cloud, 30 of which are protostellar and 92 starless. The global
protostellar luminosity function is obtained by merging the Spitzer and
Herschel protostars. Considering that 10 protostars are found in both Spitzer
and Herschel list it follows that in the investigated region we find 53
protostars and that the Spitzer selected protostars account for approximately
two-thirds of the total.Comment: 40 pages, 12 figures, accepted for publication in Ap
The X-ray eclipse of the dwarf nova HT CAS observed by the XMM-Newton satellite: spectral and timing analysis
A cataclysmic variable is a binary system consisting of a white dwarf that
accretes material from a secondary object via the Roche-lobe mechanism. In the
case of long enough observation, a detailed temporal analysis can be performed,
allowing the physical properties of the binary system to be determined. We
present an XMM-Newton observation of the dwarf nova HT Cas acquired to resolve
the binary system eclipses and constrain the origin of the X-rays observed. We
also compare our results with previous ROSAT and ASCA data. After the spectral
analysis of the three EPIC camera signals, the observed X-ray light curve was
studied with well known techniques and the eclipse contact points obtained.
The X-ray spectrum can be described by thermal bremsstrahlung of temperature
keV plus a black-body component (upper limit) with
temperature eV. Neglecting the black-body, the bolometric
absorption corrected flux is erg
s cm, which, for a distance of HT Cas of 131 pc, corresponds to a
bolometric luminosity of erg s.
The study of the eclipse in the EPIC light curve permits us to constrain the
size and location of the X-ray emitting region, which turns out to be close to
the white dwarf radius. We measure an X-ray eclipse somewhat smaller (but only
at a level of ) than the corresponding optical one. If this
is the case, we have possibly identified the signature of either high latitude
emission or a layer of X-ray emitting material partially obscured by an
accretion disk.Comment: Accepted for publication on Astronomy and Astrophysics, 200
High Aspect Ratio Silicon Wire Array Photoelectrochemical Cells
In an effort to develop low-cost solar energy conversion techniques, high uniformity vertically oriented silicon wire arrays have been fabricated. These arrays, which allow for radial diffusion of minority charge carriers, have been measured in a photoelectrochemical cell. Large photovoltages (∼400 mV) have been measured, and these values are significantly greater than those obtained from the substrate alone. Additionally, the wire array samples displayed much higher current densities than the underlying substrate, demonstrating that significant energy conversion was occurring due to the absorption and charge-carrier transport in the vertically aligned Si wires. This method therefore represents a step toward the use of collection-limited semiconductor materials in a wire array format in macroscopic solar cell devices
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