9,983 research outputs found
Mobility networks for predicting gentrification
Gentrification is a contentious issue which local governments struggle to deal with because warning signs are not always visible. Unlike current literature that utilises solely socio-economic data, we introduce the use of large-scale spatio-temporal mobility data to predict which neighbourhoods of a city will gentrify. More specifically, from mobility data, which is associated with the exchange of ideas and capital between neighbourhoods, we construct mobility networks. Features are extracted from these mobility networks and used in gentrification prediction, which is framed as a binary classification. As a case study, we use the Taxi & Limousine Commission Trip Record Data to predict which census tracts would gentrify in New York City from 2010 to 2018, and show that considering network features alongside socio-economic features leads to a significant improvement in prediction performance
Landau-Zener transition of a two-level system driven by spin chains near their critical points
The Landau-Zener(LZ) transition of a two-level system coupling to spin chains
near their critical points is studied in this paper. Two kinds of spin chains,
the Ising spin chain and XY spin chain, are considered. We calculate and
analyze the effects of system-chain coupling on the LZ transition. A relation
between the LZ transition and the critical points of the spin chain is
established. These results suggest that LZ transitions may serve as the
witnesses of criticality of the spin chain. This may provide a new way to study
quantum phase transitions as well as LZ transitions.Comment: 5 pages, 4 figures. European Physical Journals D accepte
Cascaded Parametric Amplification for Highly Efficient Terahertz Generation
A highly efficient, practical approach to high-energy terahertz (THz)
generation based on spectrally cascaded optical parametric amplification
(THz-COPA) is introduced. The THz wave initially generated by difference
frequency generation between a strong narrowband optical pump and optical seed
(0.1-10% of pump energy) kick-starts a repeated or cascaded energy
down-conversion of pump photons. This helps to greatly surpass the
quantum-defect efficiency and results in exponential growth of THz energy over
crystal length. In cryogenically cooled periodically poled lithium niobate,
energy conversion efficiencies >8% for 100 ps pulses are predicted. The
calculations account for cascading effects, absorption, dispersion and
laser-induced damage. Due to the coupled nonlinear interaction of multiple
triplets of waves, THz-COPA exhibits physics distinct from conventional
three-wave mixing parametric amplifiers. This in turn governs optimal
phase-matching conditions, evolution of optical spectra as well as limitations
of the nonlinear process.Comment: 5 pages, double colum
Carbon dioxide emissions of Antarctic tourism
The increase of tourism to the Antarctic continent may entail not only local but also global environmental impacts. These latter impacts, which are mainly caused by transport, have been generally ignored. As a result, there is a lack of data on the global impacts of Antarctic tourism in terms of energy consumption and carbon dioxide emissions. This paper presents and applies a methodology for quantifying CO2 emissions, both for the Antarctic vessel fleet as a whole and per passenger (both per trip and per day). The results indicate that the average tourist trip to Antarctica results in 5.44 t of CO2 emissions per passenger, or 0.49 t per passenger and day. Approximately 70% of these emissions are attributable to cruising and 30% to flying, which highlights the global environmental relevance of local transport for this type of touris
miRNAs-mediated overexpression of Periostin is correlated with poor prognosis and immune infiltration in lung squamous cell carcinoma.
Lung cancer is one of the most common malignancies with a high mortality rate worldwide. POSTN has been shown to be strongly correlated with the poor prognosis of lung cancer patients. However, the function and mechanism of action of POSTN in lung cancer remain unclear. Here, we carried out a pan-cancer analysis to assess the clinical prognostic value of POSTN based on the TCGA, TIMER, Oncomine, Kaplan-Meier, and UALCAN databases. We found that upregulated POSTN can be a promising biomarker to predict the prognosis of patients with lung cancer. High levels of POSTN correlated with immune cell infiltration in lung cancer, especially lung squamous cell carcinoma (LUSC), which was further confirmed based on the results from the TISIDB database. Moreover, the expression analysis, correlation analysis, and survival analysis revealed that POSTN-targeted miRNAs, downregulation of has-miR-144-3p and has-miR-30e-3p, were significantly linked to poor prognosis in patients with LUSC. Taken together, we identified that POSTN can act as a novel biomarker for determining the prognosis related to immune infiltration in patients with LUSC and deserves further research
Non-parametric three-way mixed ANOVA with aligned rank tests
Research problems that require a non-parametric analysis of multifactor designs with repeated measures arise in the behavioural sciences. There is, however, a lack of available procedures in commonly used statistical packages. In the present study, a generalization of the aligned rank test for the two-way interaction is proposed for the analysis of the typical sources of variation in a three-way analysis of variance (ANOVA) with repeated measures. It can be implemented in the usual statistical packages. Its statistical properties are tested by using simulation methods with two sample sizes (n = 30 and n = 10) and three distributions (normal, exponential and double exponential). Results indicate substantial increases in power for non-normal distributions in comparison with the usual parametric tests. Similar levels of Type I error for both parametric and aligned rank ANOVA were obtained with non-normal distributions and large sample sizes. Degrees-of-freedom adjustments for Type I error control in small samples are proposed. The procedure is applied to a case study with 30 participants per group where it detects gender differences in linguistic abilities in blind children not shown previously by other methods.We would like to thank Robert Steiner and David W. Smith of New Mexico State University for their support in conducting this study
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