If G is an Abelian lattice-ordered (ℓ-) group, then G is existentially closed (e.c.) just in case every finite system of ℓ-group equations and inequations, involving elements of G, that is solvable in some Abelian ℓ-group extending G is solvable already in G. If G⊆H are Abelian ℓ-groups, H is an e.c. prime-model extension of G just in case H is e.c. and is embeddable over G into every e.c. ℓ-group containing G. Though not every Abelian ℓ-group has an e.c. prime-model extension, this paper establishes existence and uniqueness of such extensions for three special kinds of Abelian ℓ-group.
Under recurring droughts, the southwestern U.S. loses a significant proportion of precipitation as evapotranspiration (ET), suggesting an opportunity to reduce ET via forest thinning. To better understand the potential impacts of thinning on the forest hydrologic cycle, we used sap flow sensors and Bowen ratio stations to measure ET in thinned and non-thinned ponderosa pine (Pinus ponderosa Douglas ex C. Lawson) stands in northern Arizona during the wet year of 2023, where thinning removed 42% of overstory basal area. Although our study site had experienced prolonged drought in previous years, heavy winter snowfall made 2023 a wet year. We correlated sap flow with environmental variables and used principal component analysis to identify the primary drivers of ponderosa pine water use in thinned and non-thinned stands. Results showed that after accounting for tree size, thinned stands had similar to 20% (similar to 5 L day(-1)) higher individual-tree water use at daily and weekly temporal scales than non-thinned stands. At the stand level, thinning decreased overstory ET (OET) but increased understory ET (UET), indicating a reallocation of outgoing water fluxes in the water balance. As a result, total ET (sum of OET and UET) decreased from 584 to 516 mm year(-1). In the semi-arid forest, this decrease in total ET of 68 mm year(-1) (similar to 12% reduction) indicates an ecohydrologically meaningful outcome of forest thinning. In both stands, tree water use was strongly regulated by environmental variables, primarily atmospheric variables such as air temperature and vapor pressure deficit. Overall, our results suggest that thinning can still promote an improved stand-level forest water balance during a wet year and thus may enhance forest resilience under projected increases in heat and aridity in the southwestern U.S.
The unavailability and inaccessibility of official crime data in developing countries present a major challenge for crime analysis. This study explores the potential of transforming news media content into a structured dataset suitable for pattern analysis in Georgetown, Guyana. A corpus of 5,487 newspaper articles was systematically extracted across three different newspaper platforms using crime-related keywords. In order to reveal the spatio-temporal pattern of crime in the city, the extracted news articles were analyzed using spatial point pattern methods. Findings revealed a clear temporal trend of crime peaking at 7:00 pm during weekdays and late in the night to early mornings on weekends. The temporal analysis also revealed that crime peaks on weekends. The spatial point pattern analysis confirmed significant clustering of crime at micro places, while the bivariate relationship showed the spatial dependence between pairs of crime types.
In the category V of unital archimedean vector lattices, several relatively recent results have brought closure to the notion of uniform completion: there are exactly four constructs worthy of the name uniform completion. In all cases completeness requires the convergence of uniformly Cauchy sequences; the completions are distinguished by the manner in which the convergence is regulated. In each case the complete objects form a full monoreflective subcategory of V , denoted respectively ucV , irucV , orucV , and *𝐜𝐕 . In this article we survey these completions, comparing and contrasting them by means of a novel pointfree variant of the classical Yosida adjunction.
This paper examines developing countries’ low administrative capacity to enforce uniform tax rates across space as a driver of capital allocation and a cause of low productivity. We rely on the Golden Tax Project, an information technology reform in China that eliminates the need for local tax-enforcing agencies to verify firm sales and purchases through onsite inspections, as a natural experiment to study the effects of fiscal capacity on firms’ location and capital allocation decisions. Exploiting the heterogeneous shocks that the reform exerts on the fiscal capacity of Chinese counties with different geographic ruggedness, we find that the Golden Tax Project significantly leveled effective tax rates across Chinese counties, which caused capital to relocate out of counties that experienced a bigger fiscal capacity boost after the reform. Such cross-county capital reallocation significantly equalized the marginal product of capital across firms and caused a rightward shift in productivities among them.
