10,268 research outputs found
Post-injection normal closure of fractures as a mechanism for induced seismicity
Understanding the controlling mechanisms underlying injection-induced
seismicity is important for optimizing reservoir productivity and addressing
seismicity-related concerns related to hydraulic stimulation in Enhanced
Geothermal Systems. Hydraulic stimulation enhances permeability through
elevated pressures, which cause normal deformations, and the shear slip of
pre-existing fractures. Previous experiments indicate that fracture deformation
in the normal direction reverses as the pressure decreases, e.g., at the end of
stimulation. We hypothesize that this normal closure of fractures enhances
pressure propagation away from the injection region and significantly increases
the potential for post-injection seismicity. To test this hypothesis, hydraulic
stimulation is modeled by numerically coupling fracture deformation, pressure
diffusion and stress alterations for a synthetic geothermal reservoir in which
the flow and mechanics are strongly affected by a complex three-dimensional
fracture network. The role of the normal closure of fractures is verified by
comparing simulations conducted with and without the normal closure effect
Reward Preferences in Domestic Horses (Equus caballus)
The present study examined stress response in domestic horses (Equus caballus) to determine if horses show preference for either traditional or natural horsemanship training methods to test the hypothesis that natural horsemanship would induce less stress. Our results show that natural horsemanship rewards elicited lower stress response in horses
Impact of soil moisture-atmosphere coupling on European climate extremes and trends in a regional climate model
Processes acting at the interface between the land surface and the atmosphere have a strong impact on the European summer climate, particularly during extreme years. These processes are to a large extent associated with soil moisture (SM). This study investigates the role of soil moisture-atmosphere coupling for the European summer climate over the period 1959-2006 using simulations with a regional climate model. The focus of this study is set on temperature and precipitation extremes and trends. The analysis is based on simulations performed with the regional climate model CLM, driven with ECMWF reanalysis and operational analysis data. The set of experiments consists of a control simulation (CTL) with interactive SM, and sensitivity experiments with prescribed SM: a dry and a wet run to determine the impact of extreme values of SM, as well as experiments with lowpass-filtered SM from CTL to quantify the impact of the temporal variability of SM on different time scales. Soil moisture-climate interactions are found to have significant effects on temperature extremes in the experiments, and impacts on precipitation extremes are also identified. Case studies of selected major summer heat waves reveal that the intraseasonal and interannual variability of SM account for 5-30% and 10-40% of the simulated heat wave anomaly, respectively. For extreme precipitation events on the other hand, only the wet-day frequency is impacted in the experiments with prescribed soil moisture. Simulated trends for the past decades, which appear consistent with projected changes for the 21st century, are identified to be at least partly linked to SM-atmosphere feedback
The cross-linguistic study of sentence production
The mechanisms underlying language production are often assumed to be universal, and hence not contingent on a speaker’s language. This assumption is problematic for at least two reasons. Given the typological diversity of the world’s languages, only a small subset of languages has actually been studied psycholinguistically. And, in some cases, these investigations have returned results that at least superficially raise doubt about the assumption of universal production mechanisms. The goal of this paper is to illustrate the need for more psycholinguistic work on a typologically more diverse set of languages. We summarize cross-linguistic work on sentence production (specifically: grammatical encoding), focusing on examples where such work has improved our theoretical understanding beyond what studies on English alone could have achieved. But cross-linguistic research has much to offer beyond the testing of existing hypotheses: it can guide the development of theories by revealing the full extent of the human ability to produce language structures. We discuss the potential for interdisciplinary collaborations, and close with a remark on the impact of language endangerment on psycholinguistic research on understudied languages
Coding Geographic Areas Across Census Years: Creating Consistent Definitions of Metropolitan Areas
This paper presents suggested matches for the geographical coding (geocoding) of metropolitan areas in the 1970, 1980, and 1990 Censuses. The Census Bureau used different definitions and taxonomies to describe the geography of metropolitan areas in these three Census years. As a result, the geographical areas referred to by the standard Census Bureau definitions differ among the three Census data sets. The geographic matching scheme explained in this paper attempts to maximize consistency over time for metropolitan areas in the U.S.
Predicting head-marking variability in Yucatec Maya relative clause production
Recent proposals hold that the cognitive systems underlying language production exhibit computational properties that facilitate communicative efficiency, i.e., an efficient trade-off between production ease and robust information transmission. We contribute to the cross-linguistic evaluation of the communicative efficiency hypothesis by investigating speakers’ preferences in the production of a typologically rare head-marking alternation that occurs in relative clause constructions in Yucatec Maya. In a sentence recall study, we find that speakers of Yucatec Maya prefer to use reduced forms of relative clause verbs when the relative clause is more contextually expected. This result is consistent with communicative efficiency and thus supports its typological generalizability. We compare two types of cue to the presence of a relative clause, pragmatic cues previously investigated in other languages and a highly predictive morphosyntactic cue specific to Yucatec. We find that Yucatec speakers’ preferences for a reduced verb form are primarily conditioned on the more informative cue. This demonstrates the role of both general principles of language production and their language-specific realizations
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