The Dilemma of Presidential Leadership

Every decade, about five thousand persons serve as college or university presidents. Over a term of office averaging less than seven years, the president is expected to serve simultaneously as the chief administrator of a large and complex bureaucracy, as the convening colleague of a professional community, as a symbolic elder in a campus culture of shared values and symbols, and (in some institutions) as a public official accountable to a public board and responsive to the demands of other governmental agencies. Balancing the conflicting expectations of these roles has always been difficult; changing demographic trends, fiscal constraints, the complexity and diversity of tasks, university dynamics, and unrealistic public expectations make it virtually impossible for most presidents to provide the leadership that is expected

Measurement of Perceived School Climate for Active Travel in Children.

Objectives : To describe the development of an original scale that measures perceived school climate for active travel in fourth- and fifth-grade girls and boys. Methods : The data were analyzed using confirmatory factor analysis (CFA) to provide evidence of factorial validity, factorial invariance, and construct validity. Results : The CFA supported the fit of a 3-factor (encouragement, praise, and importance) correlated model for the school climate for active travel measure. This hierarchical model was invariant between sex and across a 7-month time period, and initial evidence for construct validity was provided. Conclusions : School climate for active travel is a measurable construct, and preliminary evidence suggests relationships with more support for active travel from friends and family

Neurotransmitter modulation of extracellular H+ fluxes from isolated retinal horizontal cells of the skate

Self-referencing H+-selective microelectrodes were used to measure extracellular H+ fluxes from horizontal cells isolated from the skate retina. A standing H+ flux was detected from quiescent cells, indicating a higher concentration of free hydrogen ions near the extracellular surface of the cell as compared to the surrounding solution. The standing H+ flux was reduced by removal of extracellular sodium or application of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), suggesting activity of a Na+–H+ exchanger. Glutamate decreased H+ flux, lowering the concentration of free hydrogen ions around the cell. AMPA/kainate receptor agonists mimicked the response, and the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) eliminated the effects of glutamate and kainate. Metabotropic glutamate agonists were without effect. Glutamate-induced alterations in H+ flux required extracellular calcium, and were abolished when cells were bathed in an alkaline Ringer solution. Increasing intracellular calcium by photolysis of the caged calcium compound NP-EGTA also altered extracellular H+ flux. Immunocytochemical localization of the plasmalemma Ca2+–H+-ATPase (PMCA pump) revealed intense labelling within the outer plexiform layer and on isolated horizontal cells. Our results suggest that glutamate modulation of H+ flux arises from calcium entry into cells with subsequent activation of the plasmalemma Ca2+–H+-ATPase. These neurotransmitter-induced changes in extracellular pH have the potential to play a modulatory role in synaptic processing in the outer retina. However, our findings argue against the hypothesis that hydrogen ions released by horizontal cells normally act as the inhibitory feedback neurotransmitter onto photoreceptor synaptic terminals to create the surround portion of the centre-surround receptive fields of retinal neuron

Selected Topics In Tort Law

This speaker series took place over several days during the Spring semester of 1990. The Special Problems of Causation in Toxic Tort Cases lecture given by Sheila L. Birnbaum, Partner in the New York City firm Skadden, Arps, Slate, Meagher, & Flom. (Tuesday, January 23, 1990) Damage Recovery in Toxic Tort Suits lecture given by Sheila L. Binbaum, Partner in the New York City firm Skadden, Arps, Slate, Meagher, & Flom. (Tuesday, January 30, 1990) Methods and Roles in Tort Lawmaking lecture given by The Honorable Robert Keeton, Langdell Professor Emeritus at Harvard Law School, U.S. District Court Judge for D. Mass. (Tuesday, February 13 and February 20, 1990) Procedural Innovations in and outside of the Courts and the Special Problems of Dignitary Torts lecture given by Richard Delgado, Professor of Law at the University of Wisconsin. (Date unknown) The Future of Tort Law lecture given by Deborah R. Hensler, Research Director of the Institute for Civil Justice at the RAND Corporation. (Date unknown

Naturally occurring changes in time spent watching television are inversely related to frequency of physical activity during early adolescence

In this longitudinal study, we examined the relationship between changes in time spent watching television and playing video games with frequency of leisure-time physical activity across a 2-year period among adolescent boys and girls (N=4594 role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 16.200000762939453px; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative; \u3e). Latent growth modelling indicated that a decrease in time spent watching television was associated with an increase in frequency of leisure-time physical activity. That relationship was strong in magnitude and independent of sex, socioeconomic status, smoking, and the value participants placed on health, appearance, and achievement. Our results encourage the design of interventions that reduce television watching as a possible means of increasing adolescent physical activity

Longitudinal Invariance of the Center for Epidemiologic Studies-Depression Scale among Girls and Boys in Middle School

This study tested the longitudinal factorial invariance of a theoretically consistent, higher-order model for Center for Epidemiologic Studies-Depression (CES-D) scores among adolescent girls and boys in middle school. Data were collected from 2,416 adolescents who completed a survey containing the CES-D in the fall of 1998, spring of 1999, and spring of 2000. The invariance analyses were conducted using LISREL 8.50 with maximum likelihood estimation and the Satorra-Bentler scaled chi-square statistic and standard errors. The higher-order model demonstrated longitudinal, as well as gender, invariance of the overall factor structure and first- and second-order structure coefficients, first-order factor variances, second-order factor variances, and covariances, and item uniquenesses. The results demonstrate that meaningful comparisons of composite CES-D scores can be made across time among girls and boys in middle school

Kilometer-scale digital elevation models of the sea ice surface with airborne laser scanning during MOSAiC

An integrated sensor platform including an inertial navigation system (INS) and a commercial airborne laser scanner (ALS) among other sensor was mounted in the cargo compartment in one of the Polarstern helicopters during MOSAiC. ALS data was acquired from more than 60 flights between October 2019 and September 2020 with a range of survey types intended to map changes of the sea ice surface during the full annual cycle at high spatial resolution and coverage. Here, we provide an overview of the collected data, the challenge of achieving centimeter elevation accuracy with a helicopter platform at high polar latitudes as well as the content and specifications of ALS data products. The high spatial resolution and repeated coverage of the larger area around Polarstern allow studying various surface features (e.g. pressure ridges, floes, melt ponds, snow drifts, etc.), their seasonal evolution, and their impact on atmosphere and ocean. Finally, we outline methods for planned applications, such as identifying individual floes and surface types using both measured freeboard and surface reflectance. Collocated helicopter-based optical and infrared imagery allow analyzing sea ice properties in further applications and to upscale comparable in-situ observations

Multi-sensor airborne observations of freeboard, snow depth, and sea-ice thickness in the Arctic

Sea-ice thickness is a key factor and indicator in understanding the impact of the global climate change. Deriving basin-wide sea-ice thickness estimates from satellite laser and radar altimetry relies on freeboard measurements. The freeboard-to-thickness conversion in turn requires information of snow mass and the density of the sea-ice layer that have unknown spatio-temporal variabilities and trends directly translating into the uncertainty of decadal sea-ice thickness data records. In addition, inter-mission biases arise from, e.g., different sensor types and frequencies as well as varying footprint sizes affected by surface roughness across regions and seasons. Therefore, carrying out validation and inter-calibration studies is crucial for reliable and continuous observation of the Earth’s cryosphere. To achieve this, it is beneficial to have simultaneous measurements of freeboard, snow depth, and sea-ice thickness, which provide reference data for both direct satellite observations and geophysical target parameters. Here, we present Alfred Wegener Institute’s (AWI) IceBird program, which is a series of fixed-wing aircraft campaigns to measure Arctic sea ice and to monitor its change. During two late-winter campaigns in the western Arctic Ocean in 2017 and 2019, we have carried out surveys with the unique scientific instrument configuration including an airborne laser scanner (ALS) for surface topography and freeboard measurements, a tethered electromagnetic induction sounding instrument (EM-Bird) for total (snow+ice) thickness measurements, and an ultrawideband frequency-modulated continuous-wave microwave radar to measure snow thickness. Therefore, we are able to observe all three bounding interfaces in the sea-ice–snow system in high resolution along survey tracks on regional scales. During the ship-based drift expedition Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) between October 2019 and September 2020, helicopter surveys were carried out in high spatio-temporal resolution throughout the year, including the polar night, to measure freeboard and roughness with the ALS both in local grid pattern and in larger scale. Coincident EM-Bird ice thickness data and information from snow measurements on the ground will help linking these parameters and monitor them and their effect on satellite retrievals for a full seasonal cycle. The individual parameters are important for describing and monitoring the state of the Arctic sea ice and validating retrievals from satellite data, but combined they offer further possibilities to characterise sea ice. By assuming isostatic equilibrium, we are able to estimate up-to-date bulk density values for different sea-ice types from the IceBird data and to derive a parametrisation of sea-ice bulk density based on sea-ice freeboard. These data allow us to explore spatio-temporal variations in sea-ice parameters observable from space and to evaluate the validity of the freeboard-to-thickness conversion in satellite altimetry through comparison against dedicated satellite overpasses and orbit collections