Abundance of Alnus incana ssp. rugosa in Adirondack Mountain shrub wetlands and its influence on inorganic nitrogen.

The purpose of this research was to determine the abundance of the nitrogen-fixing shrub, Alnus incana ssp. rugosa (speckled alder), in shrub wetlands of the Adirondack Mountain region of New York State and to determine whether its abundance affects the concentration or accumulation of inorganic nitrogen in wetland substrates. Alder/willow wetlands are the second most common wetland type in the Adirondack region. The Adirondack Park Agency's digital GIS database of wetland types was used to determine the areal extent of alder/willow wetlands in the Adirondacks. Randomly selected wetlands were sampled to determine the size and abundance of alder. Alder densities averaged approximately 7000 stems ha(-1) and alder was present in 75% of the wetlands. As an indication of short-term accumulation of NO(3-) and NH4(+) in wetland substrates, ion exchange resins were used to sample ground water in high and low alder density wetlands as well as from wetlands lacking alder and dominated by conifers. Additionally, NO(3-) and NH(4+) concentrations in ground water samples were measured. NH(4+) accumulation levels from exchange resins were low for all wetland types while groundwater NH(4+) concentration was highest in the low-density alder sites. Wetlands with high alder density had approximately six times higher NO(3-) accumulation than other wetlands. Substrate groundwater NO(3-) concentrations in wetlands of high-density alder exceeded by three times levels in low or no alder wetlands, showing the importance of alder to local N budgets. To assess the recovery of shrub wetlands from acidification, future studies should determine the fate of fixed N in wetland systems.

Psychosocial sequelae of visual loss in diabetes.

This study evaluated whether degree of related visual impairment is associated with degree of psychological symptoms in general, and specifically more somatization, depression, anxiety, phobic anxiety, fear of hypoglycemia, and stress. A total of 49 volunteer subjects with diabetes-induced visual impairment were subdivided into totally blind and partially sighted groups, and were compared with 62 nonvisually impaired adults with diabetes. All were given the Brief Symptom Index, the Hypoglycemic Fear Survey, and the Perceived Stress Scale, along with a general questionnaire assessing demographic characteristics. Mean scores of the partially sighted group did not differ from the nonvisually impaired group, but the blind subjects reported more general psychological symptoms, somatization, anxiety, and phobic anxiety. Significantly more blind than sighted subjects exhibited clinical elevations on anxiety, phobic anxiety, and fear of hypoglycemia. Regression analysis confirmed the significant visual loss on psychological functioning and revealed large individual differences in how patients respond to visual loss. (ABSTRACT TRUNCATED)

A new nausea model in humans produces mild nausea without electrogastrogram and vasopressin changes.

UNLABELLED: The standard human vection model utilized for nausea has been an optokinetic drum. This model may be difficult to extrapolate to the usual clinical setting. Our goals were to develop an experimental model which could induce low grade nausea in humans and to determine the relationship between mild nausea and changes in the electrogastrogram and plasma vasopressin concentrations. METHODS: Twenty-one volunteers (11 males, mean age: 37 years) participated. At baseline and throughout the study the electrogastrogram was monitored, blood was drawn for vasopressin assay and symptoms of nausea, dizziness and headache were rated on a 0-10-point scale. Subjects were semireclined in a darkened room while viewing moving bars of light rotating at a rate of 85 degrees s-1. Subjects were asked to rate their proneness to motion sickness and their current level of anxiety at baseline. RESULTS: Eight subjects developed mild to moderate (mean: 3.6) nausea during vection. Symptoms of nausea were correlated with a reported history of motion sickness (r = 0.49, P < 0.05) but not with anxiety (r = 0.14, P = 0.54). Degrees of nausea correlated with degrees of dizziness (r = 0.47, P < 0.05) but not with headache (r = 0.29, P = 0.14). Subjects who developed mild nausea were not significantly more likely to exhibit altered electrogastrogram or vasopressin than subjects who did not report nausea. Vasopressin levels during baseline and experimental conditions were highly correlated (r = 0.66, P < 0.005 and r = 0.55 P < 0.005, respectively) with reported baseline anxiety. CONCLUSIONS: (1) This new model in humans induced mild nausea that was unrelated to electrogastrogram and vasopressin abnormalities, (2) high correlation between anxiety and vasopressin suggests that vasopressin may not be directly related to nausea, and (3) these data indicate that onset of nausea mediated centrally can occur without associated electrogastrogram changes.