On mentoring

Mentoring is one of the most important activities of members of a medical school staff; thereby they help a new generation of physicians to develop both as physicians and as persons and help them to live out their dreams

How large are returns to schooling? Hint: Money isn't everything

This paper explores the many avenues by which schooling affects lifetime well-being. Experiences and skills acquired in school reverberate throughout life, not just through higher earnings. Schooling also affects the degree one enjoys work and the likelihood of being unemployed. It leads individuals to make better decisions about health, marriage, and parenting. It also improves patience, making individuals more goal-oriented and less likely to engage in risky behavior. Schooling improves trust and social interaction, and may offer substantial consumption value to some students. We discuss various mechanisms to explain how these relationships may occur independent of wealth effects, and present evidence that non-pecuniary returns to schooling are at least as large as pecuniary ones. Ironically, one explanation why some early school leavers miss out on these high returns is that they lack the very same decision making skills that more schooling would help improve.

The shortwave radiative forcing bias of liquid and ice clouds from MODIS observations

We present an assessment of the plane-parallel bias of the shortwave cloud radiative forcing (SWCRF) of liquid and ice clouds at 1 deg scales using global MODIS (Terra and Aqua) cloud optical property retrievals for four months of the year 2005 representative of the meteorological seasons. The (negative) bias is estimated as the difference of SWCRF calculated using the Plane-Parallel Homogeneous (PPH) approximation and the Independent Column Approximation (ICA). PPH calculations use MODIS-derived gridpoint means while ICA calculations use distributions of cloud optical thickness and effective radius. Assisted by a broadband solar radiative transfer algorithm, we find that the absolute value of global SWCRF bias of liquid clouds at the top of the atmosphere is about 6 W m<sup>−2</sup> for MODIS overpass times while the SWCRF bias for ice clouds is smaller in absolute terms by about 0.7 W m<sup>−2</sup>, but with stronger spatial variability. If effective radius variability is neglected and only optical thickness horizontal variations are accounted for, the absolute SWCRF biases increase by about 0.3–0.4 W m<sup>−2</sup> on average. Marine clouds of both phases exhibit greater (more negative) SWCRF biases than continental clouds. Finally, morning (Terra)–afternoon (Aqua) differences in SWCRF bias are much more pronounced for ice clouds, up to about 15% (Aqua producing stronger negative bias) on global scales, with virtually all contribution to the difference coming from land areas. The substantial magnitude of the global SWCRF bias, which for clouds of both phases is collectively about 4 W m<sup>−2</sup> for diurnal averages, should be considered a strong motivation for global climate modelers to accelerate efforts linking cloud schemes capable of subgrid condensate variability with appropriate radiative transfer schemes

Longwave Band-by-band Cloud Radiative Effect and its Application in GCM Evaluation

The cloud radiative effect (CRE) of each longwave (LW) absorption band of a GCM fs radiation code is uniquely valuable for GCM evaluation because (1) comparing band-by-band CRE avoids the compensating biases in the broadband CRE comparison and (2) the fractional contribution of each band to the LW broadband CRE (f(sub CRE)) is sensitive to cloud top height but largely insensitive to cloud fraction, presenting thus a diagnostic metric to separate the two macroscopic properties of clouds. Recent studies led by the first author have established methods to derive such band ]by ]band quantities from collocated AIRS and CERES observations. We present here a study that compares the observed band-by-band CRE over the tropical oceans with those simulated by three different atmospheric GCMs (GFDL AM2, NASA GEOS-5, and CCCma CanAM4) forced by observed SST. The models agree with observation on the annual ]mean LW broadband CRE over the tropical oceans within +/-1W/sq m. However, the differences among these three GCMs in some bands can be as large as or even larger than +/-1W/sq m. Observed seasonal cycles of f(sub CRE) in major bands are shown to be consistent with the seasonal cycle of cloud top pressure for both the amplitude and the phase. However, while the three simulated seasonal cycles of f(sub CRE) agree with observations on the phase, the amplitudes are underestimated. Simulated interannual anomalies from GFDL AM2 and CCCma CanAM4 are in phase with observed anomalies. The spatial distribution of f(sub CRE) highlights the discrepancies between models and observation over the low-cloud regions and the compensating biases from different bands

Dialysis solution containing hyaluronan: Effect on peritoneal permeability and inflammation in rats

Dialysis solution containing hyaluronan: Effect on peritoneal permeability and inflammation in rats.BackgroundHyaluronan (HA), a high molecular weight mucopolysaccharide found in interstitial tissues and fluid, is lost from the peritoneal cavity during peritoneal dialysis. In order to determine the role of HA in peritoneal function, we investigated the effects of exogenous HA on peritoneal permeability, markers of intraperitoneal inflammation, and peritoneal morphology in rats exposed to peritoneal dialysis solution for four weeks.MethodsWistar rats were infused intraperitoneally, twice daily, with conventional, hypertonic dialysis solution (Dianeal 3.86%; control) or Dianeal solution containing 10 mg/dL of high molecular weight HA. Peritoneal permeabilities and clearances of solutes and protein were determined using a modified peritoneal permeability test (peritoneal equilibration test) at the beginning and the end of the treatment. Peritoneal volume and ultrafiltration were determined using a macromolecular marker and by gravimetric methods. Peritoneal inflammation was determined by cell counts and differential and by the measurement of cytokine concentrations in the dialysate effluent. Peritoneal thickness and HA content were determined in liver and mesentery biopsies taken at the end of the experiment.ResultsAfter four weeks of exposure to the dialysis solution, transperitoneal protein equilibration was significantly lower in HA-treated rats compared with rats treated with Dianeal alone (46% lower for albumin, P < 0.001; 33% lower for total protein, P < 0.001). The total drained volume after a four hour dwell was 29% higher in the HA group compared with the control (P < 0.001), yielding a positive net ultrafiltration in the HA group versus a negative net ultrafiltration in controls. Peritoneal clearances of urea and creatinine tended to be elevated in HA-treated rats, while clearances of total protein and albumin tended to be lower. Dialysate effluent from rats exposed to HA contained a lower percentage of neutrophils (8.8 ± 6.7 vs. 22.8 ± 9.5%, P < 0.01) and lower levels of the cytokines, tumor necrosis factor-α (11.2 ± 14.7 vs. 42.3 ± 35.3 pg/mL, P < 0.05) and monocyte chemoattractant protein-1 MCP-1 (72.0 ± 86.5 vs. 402.4 ± 258.3 pg/mL, P < 0.02), compared with rats treated with Dianeal alone. The thickness of the peritoneal interstitium showed a similar increase in both groups, but mesenteric tissue from the HA group contained more HA (48%, P < 0.01) than tissue from control animals.ConclusionsThe addition of HA to peritoneal dialysis solution decreases protein permeability, increases ultrafiltration, and decreases cytokine levels and the proportion of peritoneal neutrophils in dialysate from rats exposed to hypertonic dialysis solution. These results suggest that exogenous HA may help to protect the peritoneal membrane during exposure to dialysis solutions. These benefits, if sustained in the clinical setting, could lead to improvements in the therapy of peritoneal dialysis

The use of happiness research for public policy

Research on happiness tends to follow a "benevolent dictator" approach where politicians pursue people's happiness. This paper takes an antithetic approach based on the insights of public choice theory. First, we inquire how the results of happiness research may be used to improve the choice of institutions. Second, we show that the policy approach matters for the choice of research questions and the kind of knowledge happiness research aims to provide. Third, we emphasize that there is no shortcut to an optimal policy maximizing some happiness indicator or social welfare function since governments have an incentive to manipulate this indicator

How to Educate Entrepreneurs?

Entrepreneurship education has two purposes: To improve students’ entrepreneurial skills and to provide impetus to those suited to entrepreneurship while discouraging the rest. While entrepreneurship education helps students to make a vocational decision its effects may conflict for those not suited to entrepreneurship. This study shows that vocational and the skill formation effects of entrepreneurship education can be identified empirically by drawing on the Theory of Planned Behavior. This is embedded in a structural equation model which we estimate and test using a robust 2SLS estimator. We find that the attitudinal factors posited by the Theory of Planned Behavior are positively correlated with students’ entrepreneurial intentions. While conflicting effects of vocational and skill directed course content are observed in some individuals, overall these types of content are complements. This finding contradicts previous results in the literature. We reconcile the conflicting findings and discuss implications for the design of entrepreneurship courses

Intercomparison of shortwave radiative transfer schemes in global aerosol modeling: results from the AeroCom Radiative Transfer Experiment

In this study we examine the performance of 31 global model radiative transfer schemes in cloud-free conditions with prescribed gaseous absorbers and no aerosols (Rayleigh atmosphere), with prescribed scattering-only aerosols, and with more absorbing aerosols. Results are compared to benchmark results from high-resolution, multi-angular line-by-line radiation models. For purely scattering aerosols, model bias relative to the line-by-line models in the top-of-the atmosphere aerosol radiative forcing ranges from roughly −10 to 20%, with over- and underestimates of radiative cooling at lower and higher solar zenith angle, respectively. Inter-model diversity (relative standard deviation) increases from ~10 to 15% as solar zenith angle decreases. Inter-model diversity in atmospheric and surface forcing decreases with increased aerosol absorption, indicating that the treatment of multiple-scattering is more variable than aerosol absorption in the models considered. Aerosol radiative forcing results from multi-stream models are generally in better agreement with the line-by-line results than the simpler two-stream schemes. Considering radiative fluxes, model performance is generally the same or slightly better than results from previous radiation scheme intercomparisons. However, the inter-model diversity in aerosol radiative forcing remains large, primarily as a result of the treatment of multiple-scattering. Results indicate that global models that estimate aerosol radiative forcing with two-stream radiation schemes may be subject to persistent biases introduced by these schemes, particularly for regional aerosol forcing