389 research outputs found
Trends and evolution in the concept of historical towns sustainability
The present study aims to review the scientific literature on sustainable towns by tracking its evolution and trends, with reference to the Sustainable Development Goals localization, and by applying social network analysis to bibliometric science. The bibliometric analysis, implemented over the timeframe 1996-2021, allowed the generation of maps based on network data displaying the relationships among scientific journals, researchers, and countries. Two different bibliometric analyses were performed to explore the scientific literature on “sustainable historical towns” and “sustainable towns’ assessment”. The results were useful to capture the multidimensional nature of sustainable towns by analyzing a large amount of literature data while identifying the main scientific patterns in this field of science. The paper is organized as follows. Sections 1 and 2 briefly introduce the topic and goal of the study. In section 3, the concept of “historical town” is defined by a qualitative and quantitative analysis. In section 4, governance issues related to small size municipalities are described with a focus on the inner peripheral areas. In Section 5, a review of sustainable urban policy evolution at the global and European levels is presented. Section 6 illustrates the state of the art in sustainability assessment of towns, analyzing the main issues and advancements of SDGs localization in the European historical small and medium-sized towns and rural areas. Section 7 illustrates the methodology and results of the performed bibliometric network analysis. Finally, the main findings of the study and research perspectives are summarized in Section 8
Parity-dependent Kondo effect in ultrasmall metallic grains
We study the Kondo effect in an ultrasmall metallic grain, i.e. small enough
to have a discrete energy-level spectrum, by calculating the susceptibility chi
of the magnetic impurity. Our quantum Monte Carlo simulations, and analytic
solution of a simple model, show that the behavior changes dramatically
depending on whether the number of electrons in the grain is even or odd. We
suggest that the measurements of chi provide an effective experimental way of
probing the grain's number parity.Comment: 7 pages, 5 figures, accepted for publication on Europhysics Letter
Intra-molecular coupling as a mechanism for a liquid-liquid phase transition
We study a model for water with a tunable intra-molecular interaction
, using mean field theory and off-lattice Monte Carlo simulations.
For all , the model displays a temperature of maximum
density.For a finite intra-molecular interaction ,our
calculations support the presence of a liquid-liquid phase transition with a
possible liquid-liquid critical point for water, likely pre-empted by
inevitable freezing. For J=0 the liquid-liquid critical point disappears at
T=0.Comment: 8 pages, 4 figure
Liquid Polymorphism and Double Criticality in a Lattice Gas Model
We analyze the possible phase diagrams of a simple model for an associating
liquid proposed previously. Our two-dimensional lattice model combines
oreintati onal ice-like interactions and \"{}Van der Waals\"{} interactions
which may be repulsive, and in this case represent a penalty for distortion of
hydrogen bonds in the presence of extra molecules. These interactions can be
interpreted in terms of two competing distances, but not necessarily soft-core.
We present mean -field calculations and an exhaustive simulation study for
different parameters which represent relative strength of the bonding
interaction to the energy penalty for its distortion. As this ratio decreases,
a smooth disappearance of the doubl e criticality occurs. Possible connections
to liquid-liquid transitions of molecul ar liquids are suggested
Percolation transition and the onset of non exponential relaxation in fully frustrated models
We numerically study the dynamical properties of fully frustrated models in 2
and 3 dimensions. The results obtained support the hypothesis that the
percolation transition of the Kasteleyn-Fortuin clusters corresponds to the
onset of stretched exponential autocorrelation functions in systems without
disorder. This dynamical behavior may be due to the ``large scale'' effects of
frustration, present below the percolation threshold. Moreover these results
are consistent with the picture suggested by Campbell et al. in space of
configurations.Comment: 8 pages, 11 figures, revised versio
Stepwise shortening of agalsidase beta infusion duration in Fabry disease: Clinical experience with infusion rate escalation protocol
Background: Although enzyme replacement therapy with agalsidase beta resulted in a variety of clinical benefits, life-long biweekly intravenous infusion may impact on patients’ quality of life. Moreover, regular infusions are time-consuming: although a stepwise shortening of infusion duration is allowed up to a minimum of 1.5 hr, in most centers it remains ≥3 hr, and no data exists about the safety and tolerability of agalsidase beta administration at maximum tolerated infusion rate. Methods: In this study, we reported our experience with a stepwise infusion rate escalation protocol developed in our center in a cohort of 53 Fabry patients (both already receiving and treatment-naΪve), and explored factors predictive for the infusion rate increase tolerability. Results: Fifty-two patients (98%) reduced infusion duration ≤3 hr; of these, 38 (72%) even reached a duration ≤2 hr. We found a significant difference between the mean duration reached by already treated and naΪve patients (p <.01). More severely affected patients (male patients and those with lower enzyme activity) received longer infusions for higher risk of infusion-associated reactions (IARs). A significant correlation between anti-agalsidase antibodies and IARs was found. Conclusion: Our infusion rate escalation protocol is safe and could improve patient compliance, satisfaction and quality of life
Structural transitions and nonmonotonic relaxation processes in liquid metals
Structural transitions in melts as well as their dynamics are considered. It
is supposed that liquid represents the solution of relatively stable solid-like
locally favored structures (LFS) in the surrounding of disordered normal-liquid
structures. Within the framework of this approach the step changes of liquid Co
viscosity are considered as liquid-liquid transitions. It is supposed that this
sort of transitions represents the cooperative medium-range bond ordering, and
corresponds to the transition of the "Newtonian fluid" to the "structured
fluid". It is shown that relaxation processes with oscillating-like time
behavior (~) of viscosity are possibly close to
this point
Periodic Bedrock Ridges at the ExoMars 2022 Landing Site: Evidence for a Changing Wind Regime
Wind-formed features are abundant in Oxia Planum (Mars), the landing site of the 2022 ExoMars mission, which shows geological evidence for a past wet environment. Studies of aeolian bedforms at the landing site were focused on assessing the risk for rover trafficability, however their potential in recording climatic fluctuations has not been explored. Here we show that the landing site experienced multiple climatic changes in the Amazonian, which are recorded by an intriguing set of ridges that we interpret as Periodic Bedrock Ridges (PBRs). Clues for a PBR origin result from ridge regularity, defect terminations, and the presence of preserved megaripples detaching from the PBRs. PBR orientation differs from superimposed transverse aeolian ridges pointing toward a major change in wind regime. Our results provide constrains on PBR formation mechanisms and offer indications on paleo winds that will be crucial for understanding the landing site geology
Liquid-Liquid Phase Transition for an Attractive Isotropic Potential with Wide Repulsive Range
Recent experimental and theoretical results have shown the existence of a
liquid-liquid phase transition in isotropic systems, such as biological
solutions and colloids, whose interaction can be represented via an effective
potential with a repulsive soft-core and an attractive part. We investigate how
the phase diagram of a schematic general isotropic system, interacting via a
soft-core squared attractive potential, changes by varying the parameters of
the potential. It has been shown that this potential has a phase diagram with a
liquid-liquid phase transition in addition to the standard gas-liquid phase
transition and that, for a short-range soft-core, the phase diagram resulting
from molecular dynamics simulations can be interpreted through a modified van
der Waals equation. Here we consider the case of soft-core ranges comparable
with or larger than the hard-core diameter. Because an analysis using molecular
dynamics simulations of such systems or potentials is too time-demanding, we
adopt an integral equation approach in the hypernetted-chain approximation.
Thus we can estimate how the temperature and density of both critical points
depend on the potential's parameters for large soft-core ranges. The present
results confirm and extend our previous analysis, showing that this potential
has two fluid-fluid critical points that are well separated in temperature and
in density only if there is a balance between the attractive and repulsive part
of the potential. We find that for large soft-core ranges our results satisfy a
simple relation between the potential's parameters
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