scholarly journals Comparison of Methods to Reduce Sidewalk Damage from Tree Roots

2008 ◽  
Vol 34 (3) ◽  
pp. 179-183
Author(s):  
E. Thomas Smiley
Keyword(s):  
North Carolina ◽  
Research Laboratory ◽  
Long Term Effects ◽  
Tree Roots ◽  
Platanus Acerifolia ◽  
Tree Diameter ◽  
Plane Trees ◽  
Root Barriers ◽  
Root Barrier

Tree roots growing under sidewalks are known to crack or lift pavement often creating a tripping hazard for pedestrians. This experiment was conducted to determine the long-term effects of below- and alongside-pavement treatments on tree root development and sidewalk damage. London, U.K. plane trees (Platanus × acerifolia) were planted next to sidewalks at the Bartlett Tree Research Laboratory in Charlotte, North Carolina, U.S., in 1996. Treatments installed at the time of planting were: DeepRoot Universal Tree Root Barrier (UB18-2), vertical polyethylene sheet, gravel, Foamular® 150 extruded polystyrene, and a structural soil. The sidewalks and soil beneath them were removed in 2006. Minimal sidewalk lifting or cracking was associated with the DeepRoot barrier, gravel, and foam treatments. Vertical root barriers and foam resulted in fewer and deeper roots under the pavement. Treatments had no impact on tree diameter growth.

scholarly journals Farmworker and Farmer Perceptions of Farmworker Agricultural Chemical Exposure in North Carolina

1998 ◽  
Vol 57 (3) ◽  
pp. 359-368 ◽  
Author(s):  
Sara Quandt ◽  
Thomas Arcury ◽  
Colin Austin ◽  
Rosa Saavedra
Keyword(s):  
North Carolina ◽  
Chemical Exposure ◽  
Power Relationships ◽  
Long Term Effects ◽  
Agricultural Chemicals ◽  
Reinforcing Factors ◽  
Seasonal Farmworkers ◽  
A Site ◽  
Depth Interviews

Agricultural chemicals pose health risks for farmworkers engaged in cultivating and harvesting crops. In a project to develop culturally appropriate interventions to reduce farmworker exposure to agricultural chemicals, formative research used in-depth interviews and focus groups to elicit beliefs and knowledge about exposure from farmers and migrant and seasonal farmworkers in North Carolina. Farmworkers were concerned about acute effects they attributed to exposure and had little knowledge of long-term effects of low-level exposure. They believe that some individuals are inherently more susceptibility to the health effects of exposure than others; most do not recognize the skin as a site of chemical absorption. They report instances of exposure that reflect the power relationships with farmers, indicating that lack of knowledge is not the only issue that must be addressed in an intervention. Farmers believe that farmworkers are not exposed to chemicals because they do not mix or apply chemicals. Such a belief is consistent with the training received by farmers. The PRECEDE-PROCEED planning model is used to identify predisposing and reinforcing factors on which an effective intervention should focus.

scholarly journals Six-Year Evaluation of Circular Root Barriers on Two Tree Species

2009 ◽  
Vol 35 (1) ◽  
pp. 41-46
Author(s):  
Dennis Pittenger ◽  
Donald Hodel
Keyword(s):  
Surface Soil ◽  
Low Cost ◽  
Large Diameter ◽  
Tree Roots ◽  
Reduced Height ◽  
Root Barriers ◽  
Small Roots ◽  
Root Barrier ◽  
Ficus Microcarpa ◽  
Height Increase

The influence of four circular root barriers on surface root development and tree growth was evaluated on Liquidambar styraciflua (American sweetgum) and Ficus microcarpa (Indian laurel fig) in southern California, U.S. Six years after installation, root barriers had reduced the total number of roots growing in the surface 15 cm (6 in) of soil and nearly eliminated large (diameter 5 cm [2 in] or greater) surface tree roots within a 120 cm (48 in) radius of the trunk. Various sizes and types of low-cost noncommercial barriers, including a container-grown tree’s nursery container with the bottom removed, were equally effective in reducing the number of large-diameter surface roots. However, roots grew below barriers and returned to the surface soil when soil texture, bulk density, and water content were near optimum for root growth at the bottom of the barrier. Many small roots 1.25 cm (0.5 in) £ diameter less than 2.5 cm (0.5 in £ diameter to less than 1 in) were found growing in the upper 15 cm (6 in) of soil just beyond barriers within 18 to 60 cm (7 to 24 in) of the trunk. No barrier treatment reduced the number of small roots of either species beyond 60 cm (24 in) radius from the trunk. Keeping pavement at least 120 cm (48 in) away from trees would be as effective as a root barrier in reducing the possibility of damage from large surface roots. A #15 nursery container serving as a root barrier reduced caliper increase of both species, whereas this treatment and the DeepRoot® barrier treatment reduced height increase of Liquidambar.

Modeling Long-Term Effects of Altered Fire Regimes following Southern Pine Beetle Outbreaks (North Carolina)

2009 ◽  
Vol 27 (1) ◽  
pp. 24-26 ◽  
Author(s):  
W. Xi ◽  
J. D. Waldron ◽  
C. W. Lafon ◽  
D. M. Cairns ◽  
A. G. Birt ◽  
...  
Keyword(s):  
North Carolina ◽  
Fire Regimes ◽  
Southern Pine Beetle ◽  
Long Term Effects ◽  
Southern Pine ◽  
Pine Beetle

scholarly journals Measuring the Impacts of Teachers: Reply

2017 ◽  
Vol 107 (6) ◽  
pp. 1685-1717 ◽  
Author(s):  
Raj Chetty ◽  
John N. Friedman ◽  
Jonah E. Rockoff
Keyword(s):  
North Carolina ◽  
Missing Data ◽  
Los Angeles ◽  
Empirical Evidence ◽  
Replication Study ◽  
Long Term Effects ◽  
Research Designs ◽  
Using Data

Rothstein (2017) successfully replicates Chetty, Friedman, and Rockoff's (2014a, b)—henceforth, CFR's—results using data from North Carolina, but raises concerns about CFR's methods. We show that Rothstein's methodological critiques are invalid by presenting simulations and supplementary empirical evidence which show that (i) his preferred imputation of missing data generates bias; (ii) his “placebo test” rejects valid research designs; and (iii) his method of controlling for covariates yields inconsistent estimates of teachers' long-term effects. Consistent with the conclusions of Bacher-Hicks, Kane, and Staiger (2016) using data from Los Angeles, we conclude that Rothstein's replication study ultimately reinforces CFR's methods and results. (JEL H75, I21, J45)

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

Long-Term Effects of Head Lice Tx Unknown

2012 ◽  
Vol 43 (3) ◽  
pp. 42
Author(s):  
MITCHEL L. ZOLER
Keyword(s):  
Head Lice ◽  
Long Term Effects
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