scholarly journals Long-term effects of hydromorphological stream restoration on changes in microhabitats of Ephemera danica (Ephemeroptera) and its population

2020 ◽  
Vol 109 ◽  
pp. 105810
Author(s):  
Monika Szymańska ◽  
Paweł Burandt ◽  
Martyna Bąkowska ◽  
Paweł Sowiński ◽  
Natalia Mrozińska ◽  
...  
Keyword(s):  
Stream Restoration ◽  
Long Term Effects ◽  
Ephemera Danica

scholarly journals Long-term Assessment of Floodplain Reconnection as a Stream Restoration Approach for Managing Nitrogen in Groundwater and Surface Water

2021 ◽  
Author(s):  
Paul Mayer ◽  
Michael Pennino ◽  
Tammy Newcomer-Johnson
Keyword(s):  
Surface Water ◽  
Watershed Management ◽  
Stream Restoration ◽  
Specific Conductance ◽  
Urban Stream ◽  
Source Control ◽  
Long Term Effects ◽  
N Removal ◽  
Over Time

Abstract Stream restoration is a popular approach for managing nitrogen in degraded, flashy urban streams. Here, we investigated the long-term effects of geomorphic stream restoration on riparian and in-stream N transport and transformation in an urban stream in the Chesapeake Bay watershed. We examined relationships between hydrology, chemistry, and biology using a Before/After-Control/Impact (BACI) study design to determine how flashiness and N concentrations and flux changed after the restoration. We examined two independent surface water and groundwater data sets collected from 2002–2012 at our study sites in the Minebank Run watershed, modeled N flux, and compared our data to similar long-term data from the Baltimore Ecosystem Study LTER (BES) that served as reference sites. Restoration was completed during 2004 and 2005. Afterward, the monthly flashiness index, based on mean monthly discharge, decreased over time from 2002 and 2008. Groundwater nitrate (NO3−) concentrations trended slightly downward over time after the restoration at the restored site while dissolved organic carbon (DOC) concentrations trended upward whereas no trends were observed at the control site. Comparisons of NO3− concentrations with Cl− concentrations and specific conductance in both groundwater and surface water suggested that N reductions over time at the restored sites were not due to dilution. Similar patterns at BES sites suggested that declining NO3− was a function of restoration and watershed management, not larger regional factors such as decreased atmospheric inputs. DOC and NO3− were negatively related before and after restoration suggesting C limitation of N transformation. Long-term trends in surface water NO3− based on USGS data showed downward trends after restoration at both the restored and control sites while specific conductance showed no trend, suggesting that load reductions were not responsible for NO3− patterns. Modeled NO3− flux decreased post restoration in both the short and long-terms. Groundwater NO3− concentrations varied among stream features suggesting that some engineered features may be functionally better at creating optimal conditions for N removal. However, some engineered features eroded and failed post restoration thereby reducing efficacy of the restoration to reduce flashiness and NO3− flux. N management via stream restoration will be most effective where flashiness can be reduced, and DOC made available for denitrifiers. Stream restoration may be an important component of holistic watershed management including stormwater management and nutrient source control.

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

The response of skin perfusion and of rheological and immunological variables to intravenous prostanoid administration in Raynaud’s phenomenon secondary to collagenosis

VASA ◽  
2005 ◽  
Vol 34 (4) ◽  
pp. 243-249 ◽  
Author(s):  
Drinda ◽  
Neumann ◽  
Pöhlmann ◽  
Vogelsang ◽  
Stein ◽  
...  
Keyword(s):  
Laser Doppler Flowmetry ◽  
Raynaud’S Phenomenon ◽  
Raynaud's Phenomenon ◽  
Plasma Viscosity ◽  
Laser Doppler ◽  
Erythrocyte Aggregation ◽  
Control Group ◽  
Long Term Effects ◽  
Doppler Flowmetry

Background: Prostanoids are used in the treatment of Raynaud’s phenomenon and acral perfusion disorders secondary to collagenosis. In subjective terms, intravenous administration of these agents produces success in more than 50% of patients. The therapeutic outcome of clinical administration of alprostadil or iloprost may vary from individual to individual. Patients and methods: The following variables were analysed in a cross-over study in 27 patients with collagenosis and Raynaud’s phenomenon: plasma viscosity and erythrocyte aggregation (rheological variables), partial pressure of oxygen and laser Doppler flowmetry in the finger region, and lymphocyte phenotyping and interleukin (IL) determinations (immunological variables). Results: Laser Doppler flowmetry revealed significant differences between patients with secondary Raynaud’s phenomenon and a control group of 25 healthy subjects. Laser Doppler readings did not change significantly as a result of the treatments. Therapy with iloprost produced a reduction in IL-1beta, L-selectin (CD 62 L) and IL-6. Conclusion: The change in immunological variables due to iloprost may explain the long-term effects of prostaglandins in the treatment of Raynaud’s phenomenon. From our results it is not possible to infer any preference for iloprost or alprostadil.

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