1,331 research outputs found
A preliminary census of the macrofungi of Mt Wellington, Tasmania- the sequestrate species
This is the fourth and final contribution in a series of papers providing a preliminary documentation of the macrofungi of Mt Wellington, Tasmania. The earlier papers dealt with the gilled Basidiomycota, the non-gilled Basidiomycota and the Ascomycota, respectively, excluding the sequestrate species. The present paper completes the series by dealing with the sequestrate species, of which seven Ascomycota, 76 Basidiomycota, three Glomeromycota and one Zygomycota were found. Seven new genera and 25 new species to be formally described elsewhere, are recorded
Model independent result on possible diurnal effect in DAMA/LIBRA-phase1
The results obtained in the search for possible diurnal effect in the
single-hit low energy data collected by DAMA/LIBRA-phase1 (total exposure: 1.04
ton x yr) deep underground at the Gran Sasso National Laboratory (LNGS) of the
I.N.F.N. are presented. At the present level of sensitivity the presence of any
significant diurnal variation and of diurnal time structures in the data can be
excluded for both the cases of solar and sidereal time. In particular, the
diurnal modulation amplitude expected, because of the Earth diurnal motion, on
the basis of the DAMA Dark Matter annual modulation results is below the
present sensitivity.Comment: 14 pages, 5 figures, 2 tables; in publication on Eur. Phys. J.
Final model independent result of DAMA/LIBRA-phase1
The results obtained with the total exposure of 1.04 ton x yr collected by
DAMA/LIBRA-phase1 deep underground at the Gran Sasso National Laboratory (LNGS)
of the I.N.F.N. during 7 annual cycles (i.e. adding a further 0.17 ton x yr
exposure) are presented. The DAMA/LIBRA-phase1 data give evidence for the
presence of Dark Matter (DM) particles in the galactic halo, on the basis of
the exploited model independent DM annual modulation signature by using highly
radio-pure NaI(Tl) target, at 7.5 sigma C.L.. Including also the first
generation DAMA/NaI experiment (cumulative exposure 1.33 ton x yr,
corresponding to 14 annual cycles), the C.L. is 9.3 sigma and the modulation
amplitude of the single-hit events in the (2-6) keV energy interval is: (0.0112
\pm 0.0012) cpd/kg/keV; the measured phase is (144 \pm 7) days and the measured
period is (0.998 \pm 0.002) yr, values well in agreement with those expected
for DM particles. No systematic or side reaction able to mimic the exploited DM
signature has been found or suggested by anyone over more than a decade.Comment: 20 pages, 13 figures, 6 tables; in publication on Eur. Phys. J.
DAMA/LIBRA results and perspectives
The DAMA/LIBRA experiment, running at the Gran Sasso National Laboratory of
the I.N.F.N. in Italy, has a sensitive mass of about 250 kg highly radiopure
NaI(Tl). It is mainly devoted to the investigation of Dark Matter (DM)
particles in the Galactic halo by exploiting the model independent DM annual
modulation signature. The present DAMA/LIBRA experiment and the former DAMA/NaI
one (the first generation experiment having an exposed mass of about 100 kg)
have released so far results corresponding to a total exposure of 1.17 ton yr
over 13 annual cycles. They provide a model independent evidence of the
presence of DM particles in the galactic halo at 8.9 sigma C.L.. A short
summary of the obtained results is presented and future perspectives of the
experiment mentioned.Comment: 12 pages, Proceed. of the 15th Bled Workshop "What Comes Beyond
Standard Models" (December 2012), Vol. 13, No.
Dark Matter investigation by DAMA at Gran Sasso
Experimental observations and theoretical arguments at Galaxy and larger
scales have suggested that a large fraction of the Universe is composed by Dark
Matter particles. This has motivated the DAMA experimental efforts to
investigate the presence of such particles in the galactic halo by exploiting a
model independent signature and very highly radiopure set-ups deep underground.
Few introductory arguments are summarized before presenting a review of the
present model independent positive results obtained by the DAMA/NaI and
DAMA/LIBRA set-ups at the Gran Sasso National Laboratory of the INFN.
Implications and model dependent comparisons with other different kinds of
results will be shortly addressed. Some arguments put forward in literature
will be confuted.Comment: review article, 71 pages, 25 figures, 8 tables; v2: minor
modifications. In publication on the International Journal of Modern Physics
Correlation between centrality metrics and their application to the opinion model
In recent decades, a number of centrality metrics describing network
properties of nodes have been proposed to rank the importance of nodes. In
order to understand the correlations between centrality metrics and to
approximate a high-complexity centrality metric by a strongly correlated
low-complexity metric, we first study the correlation between centrality
metrics in terms of their Pearson correlation coefficient and their similarity
in ranking of nodes. In addition to considering the widely used centrality
metrics, we introduce a new centrality measure, the degree mass. The m order
degree mass of a node is the sum of the weighted degree of the node and its
neighbors no further than m hops away. We find that the B_{n}, the closeness,
and the components of x_{1} are strongly correlated with the degree, the
1st-order degree mass and the 2nd-order degree mass, respectively, in both
network models and real-world networks. We then theoretically prove that the
Pearson correlation coefficient between x_{1} and the 2nd-order degree mass is
larger than that between x_{1} and a lower order degree mass. Finally, we
investigate the effect of the inflexible antagonists selected based on
different centrality metrics in helping one opinion to compete with another in
the inflexible antagonists opinion model. Interestingly, we find that selecting
the inflexible antagonists based on the leverage, the B_{n}, or the degree is
more effective in opinion-competition than using other centrality metrics in
all types of networks. This observation is supported by our previous
observations, i.e., that there is a strong linear correlation between the
degree and the B_{n}, as well as a high centrality similarity between the
leverage and the degree.Comment: 20 page
Reversal of Hartmann's procedure through the stomal side: A new even more minimal invasive technique
Background: Several minimal invasive, mainly laparoscopic-assisted, techniques for reversal of Hartmann's procedure (HP) have been published. The purpose of this pilot study was to assess a minimal invasive procedure through the stomal site that may compare favorably with open or laparoscopic-assisted procedures in terms of operative time, hospital stay and postoperative complications. Methods: HP reversal through the stomal side was attempted in 13 consecutive patients. Lysis of intra-abdominal adhesions was done manually through an incision at the formal stoma side, without direct vision between thumb and index finger. The rectal stump was identified intra-abdominally using a transanal rigid club. A manually controlled stapled end-to-end colorectal anastomosis was created. Results: Mean duration of operation was 81 min (range 58-109 min); mean hospital stay was 4.2 days (range 2-7 days). In two patients the procedure was converted because of strong adhesions in the lower pelvic cavity around the rectal stump that could not be lysed manually safely. No complications occurred in the patients in whom reversal was completely done through the stomal site. Conclusions: In our opinion, restoration of intestinal continuity through the stomal side after HP is a feasible operation, without need for additional incisions. In the hands of a specialist gastrointestinal surgeon this technique can be attempted in all patients, as conversion to a laparoscopic-assisted or an open procedure can be performed when necessary
Sustainable institutionalized punishment requires elimination of second-order free-riders
Although empirical and theoretical studies affirm that punishment can elevate
collaborative efforts, its emergence and stability remain elusive. By
peer-punishment the sanctioning is something an individual elects to do
depending on the strategies in its neighborhood. The consequences of
unsustainable efforts are therefore local. By pool-punishment, on the other
hand, where resources for sanctioning are committed in advance and at large,
the notion of sustainability has greater significance. In a population with
free-riders, punishers must be strong in numbers to keep the "punishment pool"
from emptying. Failure to do so renders the concept of institutionalized
sanctioning futile. We show that pool-punishment in structured populations is
sustainable, but only if second-order free-riders are sanctioned as well, and
to a such degree that they cannot prevail. A discontinuous phase transition
leads to an outbreak of sustainability when punishers subvert second-order
free-riders in the competition against defectors.Comment: 7 two-column pages, 3 figures; accepted for publication in Scientific
Report
Interdependent binary choices under social influence: phase diagram for homogeneous unbiased populations
Coupled Ising models are studied in a discrete choice theory framework, where
they can be understood to represent interdependent choice making processes for
homogeneous populations under social influence. Two different coupling schemes
are considered. The nonlocal or group interdependence model is used to study
two interrelated groups making the same binary choice. The local or individual
interdependence model represents a single group where agents make two binary
choices which depend on each other. For both models, phase diagrams, and their
implications in socioeconomic contexts, are described and compared in the
absence of private deterministic utilities (zero opinion fields).Comment: 17 pages, 3 figures. This is the pre-peer reviewed version of the
following article: Ana Fern\'andez del R\'io, Elka Korutcheva and Javier de
la Rubia, Interdependent binary choices under social influence, Wiley's
Complexity, 2012; which has been published in final form at
http://onlinelibrary.wiley.com/doi/10.1002/cplx.21397/abstrac
Dynamical Patterns of Cattle Trade Movements
Despite their importance for the spread of zoonotic diseases, our
understanding of the dynamical aspects characterizing the movements of farmed
animal populations remains limited as these systems are traditionally studied
as static objects and through simplified approximations. By leveraging on the
network science approach, here we are able for the first time to fully analyze
the longitudinal dataset of Italian cattle movements that reports the mobility
of individual animals among farms on a daily basis. The complexity and
inter-relations between topology, function and dynamical nature of the system
are characterized at different spatial and time resolutions, in order to
uncover patterns and vulnerabilities fundamental for the definition of targeted
prevention and control measures for zoonotic diseases. Results show how the
stationarity of statistical distributions coexists with a strong and
non-trivial evolutionary dynamics at the node and link levels, on all
timescales. Traditional static views of the displacement network hide important
patterns of structural changes affecting nodes' centrality and farms' spreading
potential, thus limiting the efficiency of interventions based on partial
longitudinal information. By fully taking into account the longitudinal
dimension, we propose a novel definition of dynamical motifs that is able to
uncover the presence of a temporal arrow describing the evolution of the system
and the causality patterns of its displacements, shedding light on mechanisms
that may play a crucial role in the definition of preventive actions
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