Direct observations of submarine melt and subsurface geometry at a tidewater glacier.

Ice loss from the world's glaciers and ice sheets contributes to sea level rise, influences ocean circulation, and affects ecosystem productivity. Ongoing changes in glaciers and ice sheets are driven by submarine melting and iceberg calving from tidewater glacier margins. However, predictions of glacier change largely rest on unconstrained theory for submarine melting. Here, we use repeat multibeam sonar surveys to image a subsurface tidewater glacier face and document a time-variable, three-dimensional geometry linked to melting and calving patterns. Submarine melt rates are high across the entire ice face over both seasons surveyed and increase from spring to summer. The observed melt rates are up to two orders of magnitude greater than predicted by theory, challenging current simulations of ice loss from tidewater glaciers.

Environmental effects on pregnancy rate in beef cattle.

Ten years of calving records were examined from Bos taurus crossbred cows (mean of 182 cows/yr) to quantify the effects of environmental conditions during the breeding season on pregnancy rate. Estimated breeding dates were determined by subtracting 283 d from the calving date. Relationships were determined between the proportion of cows bred during the periods from the beginning of the breeding season until d 21, 42, and 60 of the breeding season and the corresponding environmental variables. Weather data were compiled from a weather station located approximately 20 km from the research site. Average daily temperature and relative humidity were used to calculate daily temperature-humidity index (THI). Daily averages for each environmental variable were averaged for each period. Minimum temperature (MNTP) and THI for the first 21 and 42 d of the breeding season were negatively associated (P < 0.001) with pregnancy rate. For the 0-to 21-d, 0- to 42-d, and 0- to 60-d breeding periods, respective r2 for average temperatures were 0.32, 0.37, and 0.11, whereas r2 for MNTP were 0.45, 0.40, and 0.10 and r2 for THI were 0.38, 0.41, and 0.11, respectively, for the same breeding periods. The negative associations of temperature and THI with pregnancy rate are most pronounced during the first 21 d of the breeding season, with a -3.79 and -2.06% change in pregnancy rate for each unit of change in MNTP and THI, respectively. A combination of environmental variables increased the R2 to 0.67. In this analysis, windspeed was found to be positively associated with pregnancy rate in all equations and increased the R2 in all breeding periods. Optimum MNTP for the 0- to 21-d, 0- to 42-d, and 0- to 60-d breeding periods was 12.6, 13.5, and 14.9 degrees C, respectively. For the 0- to 60-d breeding period, optimum THI was 68.0, whereas the THI threshold, the calculated level at which cattle will adapt, was found to be 72.9. Reductions in pregnancy rate are likely when the average MNTP and THI equal or exceed 16.7 degrees C and 72.9, respectively, and for Bos taurus beef cows that are pasture bred during a 60-d spring-summer period.

Human classical conditioning of visual compound stimuli in paired-associate tasks.

College students in introductory psychology participated in four experiments to investigate the salience of color versus figure elements of paired associates. The study also reviewed the process of learning paired associates within the context of first-order simultaneous classical conditioning. In Exp. 1, four separate classes received different treatments concerning the position and type of stimulus element (color of figure) they were instructed to recall. There were seven trials with a 30-min. delay between the sixth and seventh trials. The results indicated that the groups who were required to remember the figure element of the pairs, significantly out-performed the color groups and also learned the pairs much faster. Also, there was a sharp rise in mean correct responses remembered after a 30-min. delay for the group required to recall the color element of the paired associates. Exp. 2 was a within-subjects comparison of the effectiveness of the color and figure elements as stimuli. Again, the figures elicited more correct responses than colors. Exp. 3 tested the effectiveness within subjects of the stimulus elements as response factors. As responses, however, there were no significant differences in the number of correct answers when recalling color or figure elements until the 30-min. delay between Trials 6 and 7. As expected in Exp. 4, figures elicited significantly more functional descriptions than did colors, suggesting that figures possess a logographic nature which acts as a mnemonic device aiding in the memory of stimuli and responses.

Why pragmatics is probably enough for now.

In place of aesthetic, essentialist, or foundational pursuits, family therapy might be better served by simply seeking to be helpful. Within such a perspective, ideas are valued/embraced for their functionality and utility. In the following essay, a critical discussion concerning this pragmatic emphasis is undertaken with illustrative clinical case examples from the Eastside Family Centre in Calgary, Alberta, Canada.

Early identification and treatment necessary to prevent malnutrition in children and adolescents with severe disabilities.

Children with severe developmental disabilities frequently have nutrition and growth problems that range from moderate to severe. Because of notable continuing medical concerns and lowered growth expectations, parents and physicians may fail to recognize gradual deterioration in nutritional status before severe medical complications occur. The two cases reported in this article illustrate the need for early identification and treatment to prevent the development of notable morbidity secondary to malnutrition. Children and adolescents who have growth parameters consistently below age norms require assessment and monitoring by a registered dietitian to detect feeding problems and intake changes and to provide early intervention to help prevent negative consequences (eg, dehydration, protein-energy malnutrition, decubitus ulcers, increased rate and duration of infections, and altered bowel motility). An initial assessment should consist of measurement of length or height, weight, triceps, and subcapsular skinfolds; dietary and feeding history and a review of medical history; and biochemical testing as indicated by the medical and dietary histories. Monitoring frequency, which is determined by age, severity of condition, and response to treatment, may vary from weekly to bimonthly.

A single-pool model for intracellular calcium oscillations and waves in the Xenopus laevis oocyte.

We construct a minimal model of cytosolic free Ca2+ oscillations based on Ca2+ release via the inositol 1,4,5-trisphosphate (IP3) receptor/Ca2+ channel (IP3R) of a single intracellular Ca2+ pool. The model relies on experimental evidence that the cytosolic free calcium concentration ([Ca2+]c) modulates the IP3R in a biphasic manner, with Ca2+ release inhibited by low and high [Ca2+]c and facilitated by intermediate [Ca2+]c, and that channel inactivation occurs on a slower time scale than activation. The model produces [Ca2+]c oscillations at constant [IP3] and reproduces a number of crucial experiments. The two-dimensional spatial model with IP3 dynamics, cytosolic diffusion of IP3 (Dp = 300 microns 2 s-1), and cytosolic diffusion of Ca2+ (Dc = 20 microns 2 s-1) produces circular, planar, and spiral waves of Ca2+ with speeds of 7-15 microns.s-1, which annihilate upon collision. Increasing extracellular [Ca2+] influx increases wave speed and baseline [Ca2+]c. A [Ca2+]c-dependent Ca2+ diffusion coefficient does not alter the qualitative behavior of the model. An important model prediction is that channel inactivation must occur on a slower time scale than activation in order for waves to propagate. The model serves to capture the essential macroscopic mechanisms that are involved in the production of intracellular Ca2+ oscillations and traveling waves in the Xenopus laevis oocyte.

Calcium waves.

Intracellular Ca2+ oscillations and waves are commonly observed both in excitable cells, including neurons, and in non-excitable cells. Current attempts to describe and explain these complex intracellular signals suggest that the oscillations are the result of a highly regulated mechanism, the details of which vary among different cells. Recently, the Xenopus oocyte has become an important model system in which a single pool of IP3 receptors release Ca2+ to initiate waves. The intrinsic bell-shaped dependence of the IP3 receptor on Ca2+ is sufficient to explain the regenerative wave phenomenon.

Preferential denervation of the adductor muscles of the equine larynx. I: Muscle pathology.

The laryngeal muscles of 18 horses were examined histologically. The neurogenic changes found in each muscle were scored by four reviewers and the results evaluated statistically. Fifteen of these horses had endoscopic evidence of abnormal laryngeal function, three of which were defined as having adductor paralysis. Measurement of muscle fibre area in two horses with idiopathic laryngeal hemiplegia (ILH) was performed. In the quantitative study of neurogenic change, the adductor muscles were more significantly affected than the abductor muscle. This was also true in the clinical cases of ILH where measurement of muscle fibre area demonstrated that the lateral cricoarytenoid (adductor) muscles showed a wider range of pathological changes than the dorsal cricoarytenoid muscle (abductor). Those horses with the most severe muscle pathology also had the most abnormal endoscopic findings. The propensity for denervation of the adductor muscles should provide clues as to the pathogenesis and natural history of horses with sub-clinical laryngeal disease and ILH.

A joystick controlled wheelchair.

A joystick based motor control for a child's wheelchair was designed and built. The design is intended to allow a child with limited strength to control a wheelchair. There is a master power switch that can be turned on and off by an instructor in a classroom situation. The joystick is made from resistors that provide the input to the pulse width modulation (PWM) circuits. The motors for each back wheel are operated by an H bridge network. The controller is built but modifications are needed for it to work properly.