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Planetary boundary layer (PBL) flows are known to exhibit fundamental differences depending on the r combination of wind shear and buoyancy forces. These differences are not unexpected in that shear in occur locally, while buoyancy force sets up vigorous thermals, which result in nonlocal transport of momentum. At the same time, these two forces can act together to modify the flow field. In this stud large-eddy simulations (LESs) spanning the shear and buoyancy flow regimes were generated; two corre to the extreme cases of shear and buoyancy-driven PBLs, while the other two represent intermediate P both forces are important. The extreme cases are used to highlight and quantify the basic difference shear and convective PBLs in 1) flow structures, 2) overall statistics, and 3) turbulent kinetic ene budget distributions. Results from the two intermediate LES cases are used to develop and verify a v scaling and a TKE budget model, which are proposed for the intermediate PBL. The velocity variances variance fluxes (i.e., third moments) normalized by this velocity scaling are shown to become quanti the order of one, and to lie mostly between those of the two extreme PBL cases. The proposed TKE bud model is shown to adequately reproduce the profiles of the TKE budget terms and the TKE.

Abstract Background Peer observation of Teaching involves observers providing descriptive feedback to their peers on learning and teaching practice as a means to improve quality of teaching. This study employed and assessed peer observation as a constructive, developmental process for members of a Pediatric Teaching Faculty. Methods This study describes how peer observation was implemented as part of a teaching faculty development program and how it was perceived by teachers. The PoT process was divided into 4 stages: pre-observation meeting, observation, post-observation feedback and reflection. Particular care was taken to ensure that teachers understood that the observation and feedback was a developmental and not an evaluative process. Twenty teachers had their teaching peer observed by trained Faculty members and gave an e-mail ‘sound-bite’ of their perceptions of the process. Teaching activities included lectures, problem-based learning, small group teaching, case-based teaching and ward-based teaching sessions. Results Teachers were given detailed verbal and written feedback based on the observer’s and students’ observations. Teachers’ perceptions were that PoT was useful and relevant to their teaching practice. Teachers valued receiving feedback and viewed PoT as an opportunity for insight and reflection. The process of PoT was viewed as non-threatening and teachers thought that PoT enhanced the quality of their teaching, promoted professional development and was critical for Faculty development. Conclusions This study demonstrated that PoT can be used in a constructive way to improve course content and delivery, to support and encourage medical teachers, and to reinforce good teaching.

Abstract Background Genomic evaluations are rapidly replacing traditional evaluation systems used for dairy cattle selection. Higher reliabilities from larger genotype files promote cooperation across country borders. Genomic information can be exchanged across countries using simple conversion equations, by modifying multi-trait across-country evaluation (MACE) to account for correlated residuals originating from the use of foreign evaluations, or by multi-trait analysis of genotypes for countries that use the same reference animals. Methods Traditional MACE assumes independent residuals because each daughter is measured in only one country. Genomic MACE could account for residual correlations using daughter equivalents from genomic data as a fraction of the total in each country and proportions of bulls shared. MACE methods developed to combine separate within-country genomic evaluations were compared to direct, multi-country analysis of combined genotypes using simulated genomic and phenotypic data for 8,193 bulls in nine countries. Results Reliabilities for young bulls were much higher for across-country than within-country genomic evaluations as measured by squared correlations of estimated with true breeding values. Gains in reliability from genomic MACE were similar to those of multi-trait evaluation of genotypes but required less computation. Sharing of reference genotypes among countries created large residual correlations, especially for young bulls, that are accounted for in genomic MACE. Conclusions International genomic evaluations can be computed either by modifying MACE to account for residual correlations across countries or by multi-trait evaluation of combined genotype files. The gains in reliability justify the increased computation but require more cooperation than in previous breeding programs.

The role of gas bubbles on the air‐sea CO2 flux during Hurricane Frances (2004) is studied using a large‐eddy simulation model that couples ocean surface boundary layer turbulence, gas bubbles, and dissolved gases. In the subtropical surface ocean where gases are slightly supersaturated, gases in bubbles can still dissolve due to hydrostatic pressure and surface tension exerted on bubbles. Under the simulated conditions, the CO2 efflux with an explicit bubble effect is less than 2% of that calculated using a gas flux formula without explicit inclusion of bubble effect. The use of a gas flux parameterization without bubble‐induced supersaturation contributes to uncertainty in the global carbon budget. The results highlight the importance of bubbles under high winds even for soluble gases such as CO2 and demonstrate that gas flux parameterization derived from gases of certain solubility may not be accurate for gases of very different solubility. Plain Language Summary: Carbon dioxide (CO2) is the primary anthropogenic greenhouse gases in the atmosphere and is the gas most responsible for global warming. The ocean is an important sink of anthropogenic atmospheric CO2, yet the exchange of CO2 between the ocean and the atmosphere is not fully understood. This study reexamines the exchange of CO2 under hurricanes over the low‐latitude ocean, using hurricane Frances (2004) as an example. Previous studies show that hurricanes significantly facilitate the outgassing of CO2 due to the extreme wind. Those studies, however, do not explicitly consider gas bubbles. Gas bubbles, entrained into the ocean when ocean wave breaks, are ubiquitous under hurricanes also due to the extreme wind. While in the ocean, gas bubbles not only move around under the influence of the chaotic wind‐driven currents and their own buoyancy, but they also exchange gases with the water. Our study, using state‐of‐the‐art computer models that concurrently simulate the chaotic ocean currents, gas bubbles, and dissolved gases, demonstrates that hurricane plays a significantly smaller role in the ocean‐atmosphere transfer of CO2 than previously estimated. Key Points: Gas bubbles reduce CO2 efflux from supersaturated water by a factor of 50 under hurricane winds for the simulated conditionsBubble‐induced supersaturation should be included in gas flux parameterization for CO2 in high wind conditionsParameterizations derived using O2, N2, and inert gases may not be accurate for CO2 that has a very different solubility [ABSTRACT FROM AUTHOR]

Attitudes, beliefs, and practice teaching experience of one preservice elementary school teacher in her final year of studies and first year of teaching were examined to investigate constraints preventing the translation of educational theory into classroom practices in mathematics instruction. Results indicate that observed teaching practices contradicted stated beliefs and intentions. (21 references) (MDH)

Describes the use of spreadsheets. Presents four examples using a pre-designed format: repaying a loan, investigating functions, exponentials, and Fibonacci numbers. Provides three practice problems. (YP)

Describes attempts to move physics discussions out of the classroom and onto the Internet where students can participate any time through the use of an electronic message board. (WRM)

Large-eddy simulations of a smoke cloud are examined with respect to their sensitivity to small scales as manifest in either the grid spacing or the subgrid-scale (SGS) model. Calculations based on a Smagorinsky SGS model are found to be more sensitive to the effective resolution of the simulation than are calculations based on the prognostic turbulent kinetic energy (TKE) SGS model. The difference between calculations based on the two SGS models is attributed to the advective transport, diffusive transport, and/or time-rate-of-change terms in the TKE equation. These terms are found to be leading order in the entrainment zone and allow the SGS TKE to behave in a way that tends to compensate for changes that result in larger or smaller resolved scale entrainment fluxes. This compensating behavior of the SGS TKE model is attributed to the fact that changes that reduce the resolved entrainment flux (viz., values of the eddy viscosity in the upper part of the PBL) simultaneously tend to increase the buoyant production of SGS TKE in the radiatively destabilized portion of the smoke cloud. Increased production of SGS TKE in this region then leads to increased amounts of transported, or fossil, SGS TKE in the entrainment zone itself, which in turn leads to compensating increases in the SGS entrainment fluxes. In the Smagorinsky model, the absence of a direct connection between SGS TKE in the entrainment and radiatively destabilized zones prevents this compensating mechanism from being active, and thus leads to calculations whose entrainment rate sensitivities as a whole reflect the sensitivities of the resolved-scale fluxes to values of upper PBL eddy viscosities.