Explore the vast range of titles available.

We construct a simple model of a city with heterogeneous agents and housing choice to explain the determinants of slums, home to about one-third of the urban population in developing countries. The model supports the main empirical evidence regarding slum formation and is able quantitatively to assess the role of each determinant of slum growth. We show that urban poverty, inequality and rural–urban migration explain much of the variation in slum growth in Brazil from 1980 to 2000. Ex ante evaluation of the impacts of policy interventions shows that removing barriers to formalisation has a strong impact on slum reduction.

This paper provides evidence of the causal impact of oil discoveries on local development. Novel data covering the universe of oil wells drilled in Brazil allow us to exploit a quasiexperiment: Municipalities where oil was discovered constitute the treatment group, while municipalities with drilling but no discovery are the control group. The results show that oil discoveries significantly increase local production and have positive spillovers. Workers relocate from informal, low productivity agriculture to higher value-added activities in formal services, increasing urbanization. The results are consistent with greater local demand for non-tradable services driven by highly paid oil workers.

European mountain grasslands are affected by abandonment and are being colonized by shrubs and forest. Grassland fragmentation is caused when the forest matrix grows, and surrounding grassland is split into fragments. Multiple studies have been done on grassland fragmentation but in anthropic matrices. Grassland isolation would not be a constraint for plant dispersion since the distance between grassland fragments is usually short. However, when they are abandoned, the surrounding forest can change the environmental characteristics and small fragments can disappear. We studied abandoned Mediterranean mountain grasslands in an oak forest matrix. We surveyed the grassland communities and their soil properties in multiple fragments of different sizes and isolation distances. We classified the grassland species into different groups by habitat preference and life form and calculated the landscape fragmentation variables. We analyzed the effect of fragmentation on the richness of the grassland groups and communities. Results showed that the fragmentation variables did not have any effect on the grasslands, except at the extreme ends of the gradient of the vegetation succession. The smallest grasslands favored perennial and wetter species over annual or drier species due to wetter soil conditions and less availability of light. Annual species are more abundant in southern aspect fragments with drier conditions across the fragments. The lack of connectivity among fragments is not a problem for grassland communities at a fine scale. Annual and drier grassland species remain even in the smallest fragments, but their conservation requires maintaining a minimum fragment size more than it does landscape connectivity.

Climate projections for the near future suggest a general increase in temperatures and a decrease in precipitation in Castilla y León (Northwest Iberian Peninsula). In this context, hydrographic networks may be reduced due to the decrease in flow accumulation, which may compromise the connectivity of riparian habitats and aggravate fragmentation processes, thus potentially threatening the survival of various wild species. Regionalized climate projections were calculated based on the RCP models and the 8.5 and 4.5 scenarios for the years 2030, 2050 and 2100. From this climate modelling, flow variations in the hydrographic networks were determined for the period 2020–2100. The observed decrease in precipitation and increase in temperature point to a reduction in flow accumulation. Considering these variations, and after establishing the study habitats, the alterations in ecological connectivity were analysed using the MSPA (Morphological Spatial Pattern Analysis) and the PC (Probability of Connectivity) index. MSPA reveals a significant reduction in the number and size of potential riparian habitat cores towards the year 2100, while the PC index values decrease from 3.1% (∑ dPC) in 2020 to 2.5% (∑ dPC) in 2100. These results indicate a substantial loss of ecological connectivity and an increased fragmentation of potential riparian habitats, as well as a close relation between reduced connectivity and flow accumulation for future climate projections.

Lipid nanoparticles (LNPs) have evolved rapidly as promising delivery systems for oligonucleotides, including siRNAs. However, current clinical LNP formulations show high liver accumulation after systemic administration, which is unfavorable for the treatment of extrahepatic diseases, such as hematological disorders. Here we describe the specific targeting of LNPs to hematopoietic progenitor cells in the bone marrow. Functionalization of the LNPs with a modified Leu-Asp-Val tripeptide, a specific ligand for the very-late antigen 4 resulted in an improved uptake and functional siRNA delivery in patient-derived leukemia cells when compared to their non-targeted counterparts. Moreover, surface-modified LNPs displayed significantly improved bone-marrow accumulation and retention. These were associated with increased LNP uptake by immature hematopoietic progenitor cells, also suggesting similarly improved uptake by leukemic stem cells. In summary, we describe an LNP formulation that successfully targets the bone marrow including leukemic stem cells. Our results thereby support the further development of LNPs for targeted therapeutic interventions for leukemia and other hematological disorders.

The relationships between environmental characteristics and species richness in the grasslands of the Colombian Orinoquia are presented and analyzed using an ordinal logistic regression model. Ordinal and scale covariates were included, and their bivariate significance was assessed using Spearman’s rho and Kendall’s Tau-b. The covariates that showed statistical significance with the weighted richness thresholds (WRT) and defined the model were the soil depth and the soil moisture regime, both of which had positive correlations. In contrast, the percentage of bare soil and the monthly minimum temperature showed negative correlations. This contribution highlights the relevance of articulating and combining the floristic and phytosociological characterization of grassland vegetation to advance the predictive studies aimed at defining and understanding the potential divergent relationships between the vegetation and the basic attributes of the natural environment, along with their implications for conservation.

The classification system of plant communities using phytosociological methods can be applied to their conservation in protected areas, as well as in establishing adequate protections and granting legal status to such areas. A new integrative index is developed to classify plant communities for the evaluation of the conservation status of protected areas, obtained from the product of three statistical indices of diversity: Syntaxonomic Distinctness, Rarefaction and Areas Prioritisation, which has been named DRA (acronym of the three indices used). The DRA is used to assess whether the status granted to Protected Areas matches the values provided by the plant communities within them and which were the basis for the identification and description of the Habitats of Community Interest (Habitats Directive—92/43/CEE). The proposed method was applied to the network of protected natural areas on the Andalusian coast, including 14 areas with different protection status, where, once the plant communities they contain were identified, the DRA index was applied to each of them and compared with the Legal Protection Index, i.e., the current protection regime; it becomes clear, objectively, that not all the statuses assigned, whether the IUCN criteria or those of the Andalusian government, correspond to the real levels of protection they should have on the basis of their plant communities.

Underwater fiber optic cables commonly traverse a variety of seafloor conditions, which leads to an uneven mechanical coupling between the cable and the ocean bottom. On rough seafloor bathymetry, some cable portions might be suspended and thus susceptible to vortex‐induced vibrations (VIV) driven by deep ocean currents. Here, we examine the potential of distributed acoustic sensing (DAS) to monitor deep‐sea currents along suspended sections of underwater telecom fiber optic cables undergoing VIV. Oscillations of a seafloor fiber optic cable located in southern France are recorded by DAS along cable sections presumably hanging. Their characteristic frequencies are lower than 1 Hz, at different ocean depths, and have an amplitude‐dependency consistent with the driving mechanism being VIV. Based on a theoretical proportionality between current speed and VIV frequencies, we derive ocean current speed time series at 2,390 m depth from the vortex shedding frequencies recorded by DAS. The DAS‐derived current speed time series is in agreement with recordings by a current meter located 3.75 km away from the hanging cable section (similar dominant period, high correlation after time shift). The DAS‐derived current speed time series displays features, such as characteristic periods and spectral decay, associated with the generation of internal gravity waves and weak oceanic turbulence in the Mediterranean Sea. The results demonstrate the potential of DAS along hanging segments of fiber optic cables to monitor a wide range of oceanography processes, at depths barely studied with current instrumentation. Plain Language Summary Ocean current speed recordings are rare below 1,500 m depth due to the cost of instrumentation in deep ocean environments. In this study, we demonstrate that deep‐sea current speeds can be obtained using measurements of deformation along suspended sections of seafloor fiber optic cables by a technique called distributed acoustic sensing (DAS). As ocean currents hit hanging cable segments, they generate vortex that shed off from the cable at a frequency called “vortex shedding frequency.” We show field evidence that the resulting cable oscillations can be recorded by seafloor DAS. We infer ocean current speed time series from the vortex shedding frequencies recorded by DAS across a hanging section of an underwater fiber optic cable in southern France. The DAS‐derived time series is in agreement with the one recorded by a nearby current meter. Our results demonstrate the potential of DAS to monitor the generation of internal gravity waves in the Mediterranean Sea at depths barely studied with the current instrumentation, and suggest that the technique presented here to estimate seafloor current speeds may be used for investigating several processes in oceanography. Key Points Sections of seafloor fiber cables feature oscillations driven by ocean currents that are observable with distributed acoustic sensing (DAS) Cable oscillation frequencies provide ocean current speed time series through the Strouhal number relation of vortex‐induced vibrations Spectral analysis of DAS‐derived ocean current time series provides valuable information on oceanic internal gravity waves