Establishing the range of background for radon variations in groundwater along the Serghaya fault in southwestern Syria

Long-term groundwater radon measurements were carried out in two selected karstic springs emerging from the Serghaya fault zone in southwestern Syria. The work is aimed at determining the range of radon background along the concerned fault, which represents a prominent branch segment of the Dead Sea Fault System in the region. The obtained data was statistically analyzed and the mean radon values have been standardized in terms of probability of magnitude in order to enable the separation between normal radon variations from other anomalous or geotectonic related values. The results revealed a general background range of radon concentration varying between 5000 and 13000 Bqm-3, and thus all radon values lying outside this range were considered anomalous. However, remarkable clusters of high radon concentrations with peak values more than twice times the background level, were observed in both monitoring springs through the period (1992-1994). These abnormal radon values were positively correlated with simultaneous time of high precipitations, while no significant earthquake activities were recorded in the region during that period. Therefore, such radon signals do not seem to be a reflection of regional changes in crustal strain, but rather they mostly indicate evidences of radon response to the groundwater table fluctuations due to high precipitations. These consequences may confirm the usefulness of radon application as an important natural tracer in hydrogeological investigations.

Automated Algorithms for Multiscale Morphometry of Neuronal Dendrites

We describe the synthesis of automated neuron branching morphology and spine detection algorithms to provide multiscale three-dimensional morphological analysis of neurons. The resulting software is applied to the analysis of a high-resolution (0.098 μm × 0.098 μm × 0.081 μ m) image of an entire pyramidal neuron from layer III of the superior temporal cortex in rhesus macaque monkey. The approach provides a highly automated, complete morphological analysis of the entire neuron; each dendritic branch segment is characterized by several parameters, including branch order, length, and radius as a function of distance along the branch, as well as by the locations, lengths, shape classification (e.g., mushroom, stubby, thin), and density distribution of spines on the branch. Results for this automated analysis are compared to published results obtained by other computer-assisted manual means.

Exothermic Characteristics of Dormant Buds of Persimmon (Diospyros kaki Thunb.) in Relation to Cold Hardiness

Microcomputer-based thermal analysis (TA) was conducted on dormant mixed buds of Japanese persimmon (`Hiratanenashi'). The exotherms of buds were detected by thermoelectric modules. Flower buds of peach (Prunus persica Batsch cv. Shimizuhakuto) were also analyzed. When TA was used on a whole excised bud, including bud scales, the persimmon buds had only one exotherm at –14.3 °C, while the peach buds had high and low exotherms at –8.4 °C and –14.1 °C, respectively. However, when the exotherm was measured for the primordium, with the bud scales and transitional leaves removed, each primordium showed only one exotherm at –20.7 °C in persimmon and –11 °C in peach. Determination of killing temperature by visual observation, electrolyte leakage method, and triphenyltetrazolium chloride test revealed that the primordium of the persimmon bud was killed at about –14 °C as the excised whole bud or as the whole bud attached to the branch segment. Using the same method, the naked primordium was killed between –22 °C and –25 °C as the primordium was cooled. The peach primordium was killed at –14 °C when examined as a whole bud and at –11 °C as a naked primordium. Furthermore, the exotherm temperatures of persimmon buds and stem segments were measured at appropriate intervals during the two winter seasons 1993–95. Exotherm temperatures of persimmon buds were always higher than the low-temperature exotherm (LTE) temperatures of the stem segments and lower than the high-temperature exotherm (HTE) temperatures of the stem segments. LT50 of persimmon buds almost coincided with the exotherm temperatures of buds. A postulated role of bud scales in supercooling is discussed.

Control of Hawthorn (Two Circuli) Mealybug and A Woolly Aphid, Fort Collins, Colorado, 1995

Plots were established at the W.D. Holley Plant Environmental Research Center located on the campus of Colorado State University. Two trees, approximately 8-20 ft (4 inch dbh) and established at the site for approximately 10 years were utilized in the experiment. Individual branches were sprayed with different compounds to run-off. Each branch was treated as a single experimental unit, with a complete replication being a group of branches with similar orientation on the tree. Plot design was a RCB with 5 replications. Treatments were applied on 5 May by spraying 2 ft terminal branch segments with a pump-mister sprayer to the point of run-off. Although weather was clear at the time of application, soil moisture was high at the site due to prior rainfall and V5 inch of rain fell at the site in the 24 h following application. Treatments were sampled on 7 Jun by counting the number of mealybugs present on 19 inches of terminal branch segment. Aphid ratings were taken on the same date by assessing the damage and curling caused by an infestation of a woolly aphid. An eleven point rating system was used to rate leaf curling damage by the aphids per 19 inches of terminal branch segment. The rating scale was as follows: 0 = No leaves curled, 1 = 1-5 leaves with light curling, 2 = 6-10 leaves with light curling, 3 = 10+ leaves with light curling, 4 = 1-5 leaves with moderate curling, 5 = 1-5 leaves with moderate curling, 6 = 6-10 leaves with moderate curling, 7 = 10+ leaves with moderate curling, 8 = 1-5 leaves with severe curling, 9 = 6-10 leaves with severe curling, 10 = 10+ leaves with severe curling.

Measurement of three-dimensional lung tree structures by using computed tomography

A method was devised to computationally segment and measure three-dimensional pulmonary trees in situ. Bronchi and pulmonary vessels were computationally extracted from volumetric computed tomography data based on radiopacity differences between airway wall and airway lumen and between blood and parenchyma, respectively. The tree was reduced to a central axis to facilitate measurement of branch segment length and angle. Cross-sectional area was measured on a reconstructed computed tomography slice perpendicular to this central axis. The method was validated by scanning two Plexiglas phantoms and an intact lung. Reconstructed diameters in the phantoms were accurate for branches > 2 mm. In the lung airway branches between 1 and 2 mm in diameter were often unresolved when their angle of orientation with respect to the axis of the scanner was > 45 degrees. However, if a branch was resolved, its reconstructed diameter was little affected by orientation. This method represents a significant improvement in the analysis of complex pulmonary structures in three dimensions.

Influence of Bifurcations on Forced Oscillations in an Airway Model

Forced oscillations is a technique to determine respiratory input impedance from small amplitude sinusoidal pressure excursions introduced at the airway opening. Models used to predict respiratory input impedance typically ignore the direct effect of bifurcations on the flow, and treat airway branches as individual straight tubes placed appropriately in parallel and series. The flow within the individual tubes is assumed equivalent to that which would occur in infinitely long tubes. In this study we examined the influence of bifurcations on impedance for conditions of the forced oscillatory technique. We measured input impedance using forced oscillations in straight tubes and in an anatomically-relevant, four generation physical model of a human airway network. The input impedance measured experimentally compared well to that obtained theoretically using model predictions. The predictive scheme was based on appropriate parallel and series combinations of theoretically computed individual tube impedances, which were computed from solutions to oscillatory flow of a compressible gas in an infinitely long rigid tube. The agreement between experimental measurements and predictions indicates that bifurcations play a relatively minor direct role on the flow impedance for conditions of the forced oscillations technique. These results are explained in terms of the small tidal volumes used, whereby the axial distance traveled by a fluid particle during an oscillation cycle is appreciably smaller than branch segment lengths. Accordingly, only a small fraction of fluid particles travel through the bifurcation region, and the remainder experience an environment approaching flow in an infinite straight tube. The relevance of the study to the prediction of impedances in the human lung during forced oscillations is discussed.

DEVELOPMENT OF SAMPLING TECHNIQUES FOR THE SPRUCE BUDMOTH, ZEIRAPHERA CANADENSIS MUT. AND FREE. (LEPIDOPTERA: TORTRICIDAE)

The spatial and statistical distribution of Zeiraphera canadensis Mut. and Free. (spruce budmoth) within the crown of white spruce (< 4 m high) was investigated in northern New Brunswick. A 15-cm branch segment, measured distally from the scales of the branch’s apical growth and taken from the upper one-third of the crown, is considered an adequate sample unit for density estimates of spruce budmoth eggs and larvae. Sample sizes required to estimate spruce budmoth larval densities with given levels of precision and confidence were determined. A sequential sampling plan to classify spruce budmoth populations as low or high (potentially leading to growth reduction and deformed leaders in white spruce) was also developed.