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Carnap on Analyticity and Existence: A Clarification, Defense, and Development of Quine's Reading of Carnap's Views on Ontology
Get PDFDoes Carnap’s treatment of philosophical questions about existence, such as “Are there numbers?” and “Are there physical objects?”, depend on his analytic–synthetic distinction? If so, in what way? I answer these questions by clarifying, defending, and developing the reading of Carnap’s paper “Empiricism, Semantics, and Ontology” that W. V. Quine proposes, with little justification or explanation, in his paper “On Carnap’s Views on Ontology”. The primary methodological value of studying Quine’s reading of “Empiricism, Semantics, and Ontology” is that it prompts us to look for, and helps us to see the significance of, passages by Carnap that reveal the logical foundations of his views on ontology. Guided in this way by Quine’s reading, I show that (1) in “Empiricism, Semantics, and Ontology” Carnap’s preferred treatment of philosophical questions relies on paraphrasing them so that their answers are immediately obvious elementary logical truths, and are therefore, by his standards, trivially analytic; and (2) in its most general form, Carnap’s treatment of philosophical questions about existence depends on his controversial view that the analytic truths of a language L may include sentences that are not elementary logical truths, but that are nevertheless, by Carnap’s standards, analytic-in-L simply because we have stipulated that they are to be among the “meaning postulates” of L
Probing alkenoxy radical electronic structure using anion PEI spectroscopy
Get PDFPhotoelectron imaging spectra of three alkenoxide radical anions (3-buten-1-oxide, 3-buten-2-oxide, and 2-propenoxide) are presented and analyzed with supporting results of density functional theory calculations. In all spectra, intense detachment features are observed at approximately 2 eV electron binding energy, which is similar to the electron affinities of saturated neutral alkoxy radicals [Ramond et al., J. Chem. Phys. 112, 1158 (2000)]. Photoelectron angular distributions suggest the presence of several overlapping transitions which are assigned to the X̃ and à states of multiple energetically competitive conformers. The term energy of the à state of the 2-propenoxy radical, 0.17 eV, is higher than that of 3-buten-2-oxy (0.13 eV) and 3-buten-1-oxy (0.05 eV) radicals. Comparing the butenoxy radicals, we infer that stronger interactions between the non-bonding O 2p orbitals and the π bond increase the splitting between the ground and the first excited state in the 3-buten-2-oxy radical relative to the 3-buten-1-oxy radical
Soil Moisture and Other Hydrological Changes in a Stratospheric Aerosol Geoengineering Large Ensemble
Get PDFStratospheric sulfate aerosol geoengineering has been proposed as a potential strategy to reduce the impacts of climate change. Here we investigate the impact of stratospheric aerosol geoengineering on the terrestrial hydrological cycle. We use the Geoengineering Large Ensemble, which involves a 20‐member ensemble of simulations using the Community Earth System Model with the Whole Atmosphere Community Climate Model, in which sulfur dioxide (SO2) was injected into the stratosphere at four different locations, to maintain global mean surface temperature, and also the interhemispheric and equator‐to‐pole temperature gradients at values representative of 2020 (“baseline”) under the Representative Concentration Pathway 8.5. In our simulations, annual mean land precipitation and evapotranspiration (ET) increase by 12% each under Representative Concentration Pathway 8.5. Under the Geoengineering Large Ensemble, the hydrological cycle is suppressed compared to the baseline, with end‐of‐century decreases of 1.4% (12 ± 5 mm/year) and 3.3% (18 ± 2 mm/year) in global mean, annual mean precipitation, and ET over land, respectively. Geoengineering effectively maintains global mean soil moisture under a high CO2 scenario, although there is significant regional variability. Summertime soil moisture is reduced by 42 ± 11 kg/m2 (3.5%) and 27 ± 16 kg/m2 (2.1%) in India and the Amazon, respectively, which is dominated by the decrease in precipitation. We also compare these regional changes in soil moisture under the Geoengineering Large Ensemble with an equatorial‐only SO2 injection case and find a similar sign in residual changes, although the magnitude of the changes is larger in the equatorial run
Stratospheric Sulfate Aerosol Geoengineering Could Alter the High-Latitude Seasonal Cycle
Get PDFStratospheric aerosol geoengineering (SAG) has been proposed to reduce some impacts of anthropogenic climate change. Previous studies examined annual mean climate responses to SAG. Here we use the Stratospheric Aerosol Geoengineering Large Ensemble simulations to explore the effects of SAG on the seasonal cycle of climate change. Simulations show that relative to the present‐day climate, SAG diminishes the amplitude of the seasonal cycle of temperature at many high‐latitude locations, with warmer winters and cooler summers. The seasonal temperature shift significantly influences the seasonal cycle of snow depth and sea ice, with Arctic sea ice recovery overcompensated in summer by 52% and undercompensated in winter by 8%. We identify that both the dynamic effects of aerosol‐induced stratospheric heating and seasonal variations of sunlight contribute to the shifts in seasonal cycle. Shifts in the seasonal cycle have important ecological and environmental implications, which should be considered in geoengineering impact analysis
Systems of Social Identity: Citizen Identities Shaping Female Jordanian and Syrian Refugee Students in Amman's Public Schools
Get PDFThis study explores displacement, socialization, resistance, and citizenship by examining citizen identity formation of female schoolchildren and youths at three government (public), double-shift schools in Amman, whereby Jordanian girls attend school in the morning and Syrian refugee girls attend in the afternoon. Because Jordan (along with Lebanon) has the greatest influx of Syrian refugees in the world, school serves as a critical site for interrogating how systems of identity are upheld or altered for children and youths as a result of migration. Qualitative data from 12 focus groups with 90 students (36 Jordanians and 54 refugees) reveal a strong Arab Islamic identity. While Jordanian girls express support for king and country that exhibits pride in their Jordanian national identity, the majority of Syrian refugee girls feel a strong sense of alienation and displacement in Jordan. While proud of Jordan's role as a refugee host state to Arabs fleeing political persecution and societal destruction, some of the female participants acknowledge that Jordan may have reached its maximum capacity to assist despite its commitment to Arab unity
Bias Correction of Paleoclimatic Reconstructions: A New Look at 1,200+ Years of Upper Colorado River Flow
Get PDFBias correction, while widely used with climate‐model output, is not typically applied to paleoclimatic reconstructions. While many reconstruction models have low average error, they still may contain bias, especially in the tails of distributions. Bias correction, used cautiously, can be a valuable procedure that alters interpretations of past events. Analyzing the iconic tree‐ring reconstruction of Upper Colorado River flow, we find that its probability distribution is markedly different from that of observed flow. Using quantile mapping to bias correct the reconstruction, we analyze the full reconstructed record and two events in particular: the 1100s megadrought and the early 1600s pluvial. Overall, bias correction made the 1100s megadrought, the largest in the 1,200+year record, even more extreme. After bias correction, the early 1600s pluvial marginally exceeds the early twentieth century pluvial in magnitude but not in duration. Overall, bias correction should be considered whenever paleoclimatic reconstructions are compared directly to observations
Dynamics of Cadmium Acclimation in Daphnia pulex: Linking Fitness Costs, Cross-Tolerance, and Hyper-Induction of Metallothionein
Get PDFAcclimation increases tolerance to stress in individuals but is assumed to contribute fitness costs when the stressor is absent, though data supporting this widely held claim are sparse. Therefore, using clonal (i.e., genetically identical) cultures of Daphnia pulex, we isolated the contributions of acclimation to the regulation of the metal response gene, metallothionein 1 (MT1), and defined the reproductive benefits and costs of cadmium (Cd)-acclimation. Daphnia pulex were exposed for 50 parthenogenetic generations to environmentally realistic levels (1 μg Cd/L), and tolerance to Cd and other metals assessed during this period via standard toxicity tests. These tests revealed (1) increased tolerance to Cd compared to genetically identical nonacclimated cultures, (2) fitness costs in Cd-acclimated Daphnia when Cd was removed, and (3) cross-tolerance of Cd-acclimated Daphnia to zinc and silver, but not arsenic, thereby defining a functional role for metallothionein. Indeed, Cd-acclimated clones had significantly higher expression of MT1 mRNA than nonacclimated clones, when Cd exposed. Both the enhanced induction of MT1 and tolerant phenotype were rapidly lost when Cd was removed (1–2 generations), which is further evidence of acclimation costs. These findings provide evidence for the widely held view that acclimation is costly and are important for investigating evolutionary principles of genetic assimilation and the survival mechanisms of natural populations that face changing environments
Developing and Validating an English Proficiency Test
Get PDFIn response to the high demand for English proficiency exams for various purposes including placement, admission, certification, and program evaluation in Mexico, a university in Western Mexico created the English Proficiency Test (EPT) for the B1 level in the Common European Framework of Reference (CEFR). The EPT has been developed and piloted and is now ready to be administered for its operational use. This paper reports on the qualities of the language test which have been determined by the overall usefulness of the test in terms of several different but interrelated qualities including reliability, construct validity, authenticity, impact, and practicality. The test, which consisted of a reading, writing, speaking and listening section, was piloted with 91 students. Analyses of the test qualities revealed the test to be reliable and valid with regard to its functionality
Kinematical evolution of multiple stellar populations in star clusters
Get PDFWe present the results of a suite of N-body simulations aimed at understanding the fundamental aspects of the long-term evolution of the internal kinematics of multiple stellar populations in globular clusters. Our models enable us to study the cooperative effects of internal, relaxation-driven processes and external, tidally induced perturbations on the structural and kinematic properties of multiple-population globular clusters. To analyse the dynamical behaviour of the multiple stellar populations in a variety of spin-orbit coupling conditions, we have considered three reference cases in which the tidally perturbed star cluster rotates along an axis oriented in different directions with respect to the orbital angular momentum vector. We focus specifically on the characterization of the evolution of the degree of differential rotation and anisotropy in the velocity space, and we quantify the process of spatial and kinematic mixing of the two populations. In light of recent and forthcoming explorations of the internal kinematics of this class of stellar systems by means of line-of sight and astrometric measurements, we also investigate the implications of projection effects and spatial distribution of the stars adopted as tracers. The kinematic and structural richness emerging from our models further emphasizes the need and the importance of observational studies aimed at building a complete kinematical picture of the multiple population phenomenon