Code-switching – the alternating use of two languages in the same stretch of discourse by a bilingual speaker – is a dominant topic in the study of bilingualism and a phenomenon that generates a ...great deal of pointed discussion in the public domain. This handbook provides the most comprehensive guide to this bilingual phenomenon to date. Drawing on empirical data from a wide range of language pairings, the leading researchers in the study of bilingualism examine the linguistic, social and cognitive implications of code-switching in up-to-date and accessible survey chapters. The Cambridge Handbook of Linguistic Code-switching will serve as a vital resource for advanced undergraduate and graduate students, as a wide-ranging overview for linguists, psychologists and speech scientists and as an informative guide for educators interested in bilingual speech practices.
A Reduced Organic Carbon Component in Martian Basalts Steele, A.; McCubbin, F. M.; Fries, M. ...
Science (American Association for the Advancement of Science),
07/2012, Letnik:
337, Številka:
6091
Journal Article
Recenzirano
The source and nature of carbon on Mars have been a subject of intense speculation. We report the results of confocal Raman imaging spectroscopy on 11 martian meteorites, spanning about 4.2 billion ...years of martian history. Ten of the meteorites contain abiotic macromolecular carbon (MMC) phases detected in association with small oxide grains included within high-temperature minerals. Polycyclic aromatic hydrocarbons were detected along with MMC phases in Dar al Gani 476. The association of organic carbon within magmatic minerals indicates that martian magmas favored precipitation of reduced carbon species during crystallization. The ubiquitous distribution of abiotic organic carbon in martian igneous rocks is important for understanding the martian carbon cycle and has implications for future missions to detect possible past martian life.
Mantle plume-related magmas typically have higher chalcophile and siderophile element (CSE) contents than mid-ocean ridge basalts (MORB). These differences are often attributed to ...sulfide-under-saturation of plume-related melts. However, because of eruption-related degassing of sulfur (S) and the compositional, pressure, temperature and redox effects on S-solubility, understanding the magmatic behavior of S is challenging. Using CSE data for oceanic plateau basalts (OPB), which rarely degas S, we show that many OPB are sulfide-saturated. Differences in the timing of sulfide-saturation between individual OPB suites can be explained by pressure effects on sulfur solubility associated with ascent through over-thickened crust. Importantly, where S-degassing does occur, OPB have higher CSE contents than S-undegassed melts at similar stages of differentiation. This can be explained by resorption of earlier-formed sulfides, which might play an important role in enriching degassed melts in sulfide-compatible CSE and potentially contributes to anomalous enrichments of CSE in the crust.
Background The incidence of osteoarthritis after anterior cruciate ligament reconstruction is disturbingly high, with reports of nearly
50% of patients developing mild to moderate osteoarthritis 6 ...years after surgery. Few studies have assessed the factors involved
in the development of osteoarthritis.
Hypothesis The following 10 factors will be found to be predictive of osteoarthritis: meniscectomy, chondral damage, patellar tendon
grafting, age at surgery, time delay between injury and surgery, type and intensity of postsurgery sport, quadriceps strength,
hamstring strength, quadriceps-to-hamstring strength ratio, and residual joint laxity.
Study Design Cohort study (prognosis); Level of evidence, 1.
Methods Fifty-six subjects with anterior cruciate ligament reconstruction were followed for 6 years after surgery. Assessment included
KT-1000 arthrometer testing, isokinetic strength testing, a return-to-sport questionnaire, and a radiograph assessment. A
discriminant analysis was performed to assess which of the 10 factors could discriminate between those patients who developed
tibiofemoral and patellofemoral osteoarthritis and those who did not.
Results Five factors were found to be predictive of tibiofemoral osteoarthritis. Meniscectomy ( r = .72) and chondral damage ( r = .41) were the strongest discriminators, followed by patellar tendon grafting ( r = .37) (Ï 2 7, n = 56 = 25.48; P = .001). Weak quadriceps ( r = .39) and low quadriceps-to-hamstring strength ratios ( r = .6) were very close discriminators (Ï 2 8, n = 42 = 15.02; P = .059). For patellofemoral osteoarthritis, meniscectomy ( r = .45), chondral damage ( r = .75), and age at surgery ( r = .65) were predictors or close predictors (Ï 2 7, n = 54 = 13.30; P = .065).
Conclusion As not all 10 factors studied were predictive of osteoarthritis, the hypothesis was only partially proven. Preventing further
meniscal and chondral damage in patients with anterior cruciate ligament deficiency is critical. Grafting using the hamstring
tendons and restoration of quadriceps-to-hamstring strength balance are associated with less osteoarthritis.
Laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is one of the most popular techniques for determining trace element concentrations in sulfides. Due to the lack of ...matrix-matched standards, standardization of sulfide analyses are usually based on silicate glass calibrant materials. Matrix effects during ns-LA-ICP-MS analyses of Fe-rich sulfides were quantified for many trace elements by comparison of elemental concentrations obtained by LA-ICP-MS and electron microprobe (EPMA) for many synthetic sulfides. The data was used to obtain the fractionation indices (
F
i
, the ratio between the EPMA- and LA-ICP-MS-determined concentrations of element i) for many elements while considering Fe, Cu and Ni as internal standards. The results show that significant (>15% RD) matrix effects arise during ns-LA-ICP-MS analyses of Ti, Zn, Ge, Se, Mo, Cd, In, Sb, Te, Pb, Bi in sulfides when using Fe as the internal standard. The use of Ni as an internal standard yields on average higher
F
i
values for most elements, resulting in more pronounced matrix effects for refractory elements and less so for volatile elements, relative to Fe. The use of Cu as an internal standard yields overall more significant matrix effects for volatile elements (
i.e.
, lower
F
i
values). The
F
i
values for most elements remain constant with increasing concentrations, and matrix correction factors for these elements can therefore be applied across the ppm to wt% range. In agreement with previous observations for Fe-rich metals and silicate glasses, the magnitudes of the matrix effects for the various elements are strongly correlated with elemental volatility. This correlation was used to obtain a predictive model for describing
F
i
for Fe-rich sulfides. The results were used to assess the effects of matrix effects on calculated sulfide liquid-silicate melt partition coefficients derived from experiments. Matrix effects arising through the use of non-matrix-matched standards will result in significant discrepancies between measured and true partition coefficients, the extent mainly depending of the volatility of the element considered. Corrections on ns-LA-ICP-MS derived element concentrations therefore need to be performed to obtain true abundances in the absence of matrix-matched standards.
Matrix effects during ns-LA-ICP-MS analyses of Fe-rich sulfides were quantified for many trace elements by comparison of elemental concentrations obtained by LA-ICP-MS and electron microprobe (EPMA) for many synthetic sulfides.
Recent whole-rock magnesium-isotopic data for calcium-aluminum-rich inclusions (CAIs) in chondrite meteorites indicate that the primary nebular fractionation of aluminum from magnesium, probably by ...condensation, occurred within <20,000years at 4.567Ga. However, high-precision multicollector ion microprobe data for diverse CAIs from Vigarano (CV3) yield internal isochrons with a clearly resolved spread in initial 26Al/27Al, meaning that CAIs formed and were reprocessed over a much longer time span. Primitive (unmelted) CAIs have a consistent value of 5.2±0.1×10−5, melted CAIs range from 5.17×10−5 to 4.24×10−5, and one single object with a complex multistage history has an internal range of 26Al/27Al=(4.77−2.77)×10−5. The entire range corresponds to an age span of ~0.7Ma. Thus not all CAIs formed at “time zero”, and only the most primitive CAIs should be used as benchmarks for earliest Solar System chronology.
► Ca–Al-rich inclusions in chondrites have a well-resolved spread in initial 26Al/27Al. ► The range corresponds to an age span of ~0.7Ma. ► Only the most primitive CAIs should be benchmarks for early Solar System chronology.
We model the time variability of {approx}9000 spectroscopically confirmed quasars in SDSS Stripe 82 as a damped random walk (DRW). Using 2.7 million photometric measurements collected over 10 yr, we ...confirm the results of Kelly et al. and Kozlowski et al. that this model can explain quasar light curves at an impressive fidelity level (0.01-0.02 mag). The DRW model provides a simple, fast (O(N) for N data points), and powerful statistical description of quasar light curves by a characteristic timescale ({tau}) and an asymptotic rms variability on long timescales (SF{sub {infinity}}). We searched for correlations between these two variability parameters and physical parameters such as luminosity and black hole mass, and rest-frame wavelength. Our analysis shows SF{sub {infinity}} to increase with decreasing luminosity and rest-frame wavelength as observed previously, and without a correlation with redshift. We find a correlation between SF{sub {infinity}} and black hole mass with a power-law index of 0.18 {+-} 0.03, independent of the anti-correlation with luminosity. We find that {tau} increases with increasing wavelength with a power-law index of 0.17, remains nearly constant with redshift and luminosity, and increases with increasing black hole mass with a power-law index of 0.21 {+-} 0.07. The amplitude of variability is anti-correlated with the Eddington ratio, which suggests a scenario where optical fluctuations are tied to variations in the accretion rate. However, we find an additional dependence on luminosity and/or black hole mass that cannot be explained by the trend with Eddington ratio. The radio-loudest quasars have systematically larger variability amplitudes by about 30%, when corrected for the other observed trends, while the distribution of their characteristic timescale is indistinguishable from that of the full sample. We do not detect any statistically robust differences in the characteristic timescale and variability amplitude between the full sample and the small subsample of quasars detected by ROSAT. Our results provide a simple quantitative framework for generating mock quasar light curves, such as currently used in LSST image simulations.
Bernice Lott (1930-2022) Bullock, Heather E.
The American psychologist,
01/2024, Letnik:
79, Številka:
1
Journal Article
Recenzirano
This article memorializes Bernice Lott (1930-2022), professor emerita of psychology and women's studies at the University of Rhode Island and the first dean of the school's University College, a ...trailblazing social psychologist who redefined how we understand gender, ethnicity, and social class; a fierce feminist social justice pioneer and activist; and an extraordinary mentor and colleague. Highlights of Lott's career and professional contributions are noted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
The growing practice of community-engaged research (CER) creates new opportunities for practitioners, both to affirm the importance of critical approaches to CER and to strengthen our work by ...reflecting on the concepts and practices of our research. We offer reflections on the meanings of “community,” “engagement,” and “research” in the context of on-the-ground community–university collaborations conducted by the Blum Center on Poverty, Social Enterprise, and Participatory Governance, a campus-based research center at the University of California, Santa Cruz. This account is provided in the spirit of sharing observations, insights, and lessons learned about CER, generated through its practice in a range of community-based research projects.
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