125 research outputs found
Planning and design support tools for walkability: a guide for urban analysts
We present a survey of operational methods for walkability analysis and evaluation, which we hold to show promise as decision-support tools for sustainability-oriented planning and urban design. An initial overview of the literature revealed a subdivision of walkability studies into three main lines of research: transport and land use, urban health, and livable cities. A further selection of articles from the Scopus and Web of Science databases focused on scientific papers that deal with walkability evaluation methods and their suitability as planning and decision-support tools. This led to the definition of a taxonomy to systematize and compare the methods with regard to factors of walkability, scale of analysis, attention on profiling, aggregation methods, spatialization and sources of data used for calibration and validation. The proposed systematization aspires to offer to non-specialist but competent urban analysts a guide and an orienteering, to help them integrate walkability analysis and evaluation into their research and practice
Neighbourhood park vitality potential: From Jane Jacobs's theory to evaluation model
We construct a method to evaluate the neighbourhood park vitality potential (NPV-potential), inspired by Jane Jacobs's theory of urban and park vitality. The evaluation model produces an aggregate score of NPV-potential by combining information on the extrinsic factors of vitality, related to the park's surrounding urban area, with evaluative judgements on the intrinsic factors, related to the park's internal organisation and design. To showcase and submit the evaluation model to a preliminary test drive, we further present the results of an application on three parks in the city of Cagliari, Italy. The computed NPV-potential and the effective use of the three parks, obtained from direct observation, show a good degree of agreement. While far from a robust validation, which would require more extensive empirical studies with larger and more internally variable samples of parks, the reported agreement between the potential and the observed vitality on the ground is a preliminary indication of the possible usefulness of the proposed evaluation method for urban planning and design
Addressing Peripherality in Italy: A Critical Comparison between Inner Areas and Territorial Capital-Based Evaluations
As highlighted by the UN 2030 Agenda, sustainable development is a complex and multidimensional issue that can be effectively implemented and reached at the local level. This implies the evaluation of differences and disparities between territories in order to define local priorities and support cohesion policy objectives. This need has been addressed by the Italian "National Strategy for Inner Areas", which aims to support the growth of territories with a continuous economic and population decline. However, Inner Areas are identified by a set of indicators related to the low accessibility to Services of General Interest, neglecting other important factors that contribute to this condition. This paper proposes a critical analysis of this measurement and of the related "territorialization" of Inner Areas, by introducing a more comprehensive assessment model based on the concept of Territorial Capital (TC), which highlights a more nuanced understanding of complexities and diversities related to the potential development of a territory. In particular, the proposed model evaluates eight TC dimensions (human, social, cognitive, infrastructural, productive, relational, environmental and settlement capital), which cover a broad spectrum of Sustainable Development Goals (SDGs). In order to accurately demonstrate the differences between the results of the two evaluation methods, this paper presents the results of a case study application concerning all 377 municipalities, which compose the Autonomous Region of Sardinia (Italy). The findings of this study confirm the potential of an approach based on the Territorial Capital for place-based policymaking. TC, in fact, can become relevant for defining local priorities and supporting complex decisions, allowing governments to better design and tailor interventions for the effective and efficient management of available resources. Furthermore, these results pose new questions for future research developments in the field of sustainable and equitable development
Incorporating bio-physical sciences into a decision support tool for sustainable urban planning
Deciding upon optimum planning actions in terms of sustainable urban planning involves the consideration of multiple environmental and socio-economic criteria. The transformation of natural landscapes to urban areas affects energy and material fluxes. An important aspect of the urban environment is the urban metabolism, and changes in such metabolism need to be considered for sustainable planning decisions. A spatial Decision Support System (DSS) prototyped within the European FP7-funded project BRIDGE (sustainaBle uRban plannIng Decision support accountinG for urban mEtabolism), enables accounting for the urban metabolism of planning actions, by exploiting the current knowledge and technology of biophysical sciences. The main aim of the BRIDGE project was to bridge the knowledge and communication gap between urban planners and environmental scientists and to illustrate the advantages of considering detailed environmental information in urban planning processes. The developed DSS prototype integrates biophysical observations and simulation techniques with socio-economic aspects in fiveEuropean cities, selected as case studies for the pilot application of the tool. This paper describes the design and implementation of the BRIDGE DSS prototype, illustrates some examples of use, and highlights the need for further research and development in the field
Defining Configurable Virtual Reality Templates for End Users
This paper proposes a solution for supporting end users in configuring Virtual Reality environments by exploiting reusable templates created by experts. We identify the roles participating in the environment development and the means for delegating part of the behaviour definition to the end users. We focus in particular on enabling end users to define the environment behaviour. The solution exploits a taxonomy defining common virtual objects having high-level actions for specifying event-condition-Action rules readable as natural language sentences. End users exploit such actions to define the environment behaviour. We report on a proof-of-concept implementation of the proposed approach, on its validation through two different case studies (virtual shop and museum), and on evaluating the approach with expert users
Two nearby sub-Earth-sized exoplanet candidates in the GJ 436 system
We report the detection of UCF-1.01, a strong exoplanet candidate with a
radius 0.66 +/- 0.04 times that of Earth (R_{\oplus}). This sub-Earth-sized
planet transits the nearby M-dwarf star GJ 436 with a period of 1.365862 +/-
8x10^{-6} days. We also report evidence of a 0.65 +/- 0.06 R_{\oplus} exoplanet
candidate (labeled UCF-1.02) orbiting the same star with an undetermined
period. Using the Spitzer Space Telescope, we measure the dimming of light as
the planets pass in front of their parent star to assess their sizes and
orbital parameters. If confirmed, UCF-1.01 and UCF-1.02 would be called GJ 436c
and GJ 436d, respectively, and would be part of the first
multiple-transiting-planet system outside of the Kepler field. Assuming
Earth-like densities of 5.515 g/cm^3, we predict both candidates to have
similar masses (~0.28 Earth-masses, M_{\oplus}, 2.6 Mars-masses) and surface
gravities of ~0.65 g (where g is the gravity on Earth). UCF-1.01's equilibrium
temperature (T_{eq}, where emitted and absorbed radiation balance for an
equivalent blackbody) is 860 K, making the planet unlikely to harbor life as on
Earth. Its weak gravitational field and close proximity to its host star imply
that UCF-1.01 is unlikely to have retained its original atmosphere; however, a
transient atmosphere is possible if recent impacts or tidal heating were to
supply volatiles to the surface. We also present additional observations of GJ
436b during secondary eclipse. The 3.6-micron light curve shows indications of
stellar activity, making a reliable secondary eclipse measurement impossible. A
second non-detection at 4.5 microns supports our previous work in which we find
a methane-deficient and carbon monoxide-rich dayside atmosphere.Comment: Accepted for publication with Ap
Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b
Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on the nightside and that molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum of the hot Jupiter WASP-43b measured from 5 μm to 12 μm with the JWST’s Mid-Infrared Instrument. The spectra reveal a large day–night temperature contrast (with average brightness temperatures of 1,524 ± 35 K and 863 ± 23 K, respectively) and evidence for water absorption at all orbital phases. Comparisons with three-dimensional atmospheric models show that both the phase-curve shape and emission spectra strongly suggest the presence of nightside clouds that become optically thick to thermal emission at pressures greater than ~100 mbar. The dayside is consistent with a cloudless atmosphere above the mid-infrared photosphere. Contrary to expectations from equilibrium chemistry but consistent with disequilibrium kinetics models, methane is not detected on the nightside (2σ upper limit of 1–6 ppm, depending on model assumptions). Our results provide strong evidence that the atmosphere of WASP-43b is shaped by disequilibrium processes and provide new insights into the properties of the planet’s nightside clouds. However, the remaining discrepancies between our observations and our predictive atmospheric models emphasize the importance of further exploring the effects of clouds and disequilibrium chemistry in numerical models
Detection of Carbon Monoxide in the Atmosphere of WASP-39b Applying Standard Cross-Correlation Techniques to JWST NIRSpec G395H Data
Carbon monoxide was recently reported in the atmosphere of the hot Jupiter
WASP-39b using the NIRSpec PRISM transit observation of this planet, collected
as part of the JWST Transiting Exoplanet Community Early Release Science (JTEC
ERS) Program. This detection, however, could not be confidently confirmed in
the initial analysis of the higher resolution observations with NIRSpec G395H
disperser. Here we confirm the detection of CO in the atmosphere of WASP-39b
using the NIRSpec G395H data and cross-correlation techniques. We do this by
searching for the CO signal in the unbinned transmission spectrum of the planet
between 4.6 and 5.0 m, where the contribution of CO is expected to be
higher than that of other anticipated molecules in the planet's atmosphere. Our
search results in a detection of CO with a cross-correlation function (CCF)
significance of when using a template with only lines. The CCF significance of the CO signal increases to when including in the template lines from additional CO isotopologues,
with the largest contribution being from . Our results
highlight how cross-correlation techniques can be a powerful tool for unveiling
the chemical composition of exoplanetary atmospheres from medium-resolution
transmission spectra, including the detection of isotopologues.Comment: Accepted for publication in The Astrophysical Journal Letter
Recommended from our members
The transiting exoplanet community early release science program for JWST
- …