Climate change, flow regulation and land-use effects on the hydrology of the Peace-Athabasca-Slave System; findings from the Northern Rivers Ecosystem Initiative.

The Northern Rivers Ecosystem Initiative (NREI) was established in the late 1990s to address important science questions resulting from previous studies undertaken by the Northern Rivers Basin Study (NRBS). This manuscript summarizes the results from a number of reports on hydrologic research conducted on the Peace-Athabasca-Slave river and lake systems. Specific concerns expressed by the NRBS and subsequent NREI focused on how these systems were being affected by climate change, flow regulation and land-use changes. Issues addressed in this report include: the fate of aquatic perched basins within the Peace-Athabasca Delta under historical and future climate trends; the sources of major floods that replenish these basins and how the frequency, magnitude and source areas of such events have changed over time; the synoptic weather patterns and atmospheric teleconnections that are responsible for the generation of major snowmelt runoff that drive major floods; the potential effect that climate and land-use changes might have on basin runoff and delta lake levels; the specific hydro-climatic conditions required to produce major ice-jam floods on the Peace River and how these may be altered by climate change; remote-sensing methods to document delta flooding and vegetation change; and the dual effect of climate and flow regulation on the water levels of Great Slave Lake and how these may affect other nearshore processes, particularly wind seiches, that influence flooding of the Slave River Delta. A review of the major findings and recommendations for future research concludes the report.

Social support of parents and grandparents in the neonatal intensive care unit.

Using an intergenerational family systems approach, the purpose of this qualitative study was to explore the experiences of preterm birth from both parents' and grandparents' perspectives. One theme that arose from the data was the families' use of a support network for coping with the stress of the birth. A discussion of the family's use of formal and informal support networks is presented.

Electron microscopic changes in human pulps after intraligamental injection.

Because of its advantages, intraligamental injection is becoming a popular anesthetic technique to achieve anesthesia in vital pulps. This study investigated the possible effects of intraligamental injection on human pulps under electron microscope. Forty-two mandibular and maxillary premolars were scheduled to be extracted for orthodontic reasons after being anesthetized with intraligamental injections of 2% lidocaine, 1:100,000 epinephrine (experimental group). The same anesthetic solution was used on the contralateral teeth with either nerve or field blocks (control group). To examine the effects of ischemia on odontoblasts, 12 anesthetized premolars were extracted, and their pulps were placed in physiologic saline solution for different time intervals (15 minutes to 6 hours). The teeth in the experimental and control groups were then reanesthetized with nerve or field blocks of 3% carbocaine without epinephrine after time periods that ranged from 15 minutes to 28 days. After extraction, the teeth were sectioned vertically and their pulps were fixed in 3% glutaraldehyde. The odontoblastic layer of each pulp was examined under electronic microscope. Nuclear and cytoplasmic changes started an hour after ischemia in the pulps placed in physiologic saline. In contrast, little or no cellular changes occurred in pulps of the experimental or controls groups. On the basis of the results, it appears that intraligamental injection has no long-term deleterious effects on pulps of young human premolars.