In the field of acupuncture research there is an implicit yet unexplored assumption that the evidence on manual and electrical stimulation techniques, derived from basic science studies, clinical trials, systematic reviews, and meta-analyses, is generally interchangeable. Such interchangeability would justify a bidirectional approach to acupuncture research, where basic science studies and clinical trials each inform the other. This article examines the validity of this fundamental assumption by critically reviewing the literature and comparing manual to electrical acupuncture in basic science studies, clinical trials, and meta-analyses. The evidence from this study does not support the assumption that these techniques are interchangeable. This article also identifies endemic methodologic limitations that have impaired progress in the field. For example, basic science studies have not matched the frequency and duration of manual needle stimulation to the frequency and duration of electrical stimulation. Further, most clinical trials purporting to compare the two types of stimulation have instead tested electroacupuncture as an adjunct to manual acupuncture. The current findings reveal fundamental gaps in the understanding of the mechanisms and relative effectiveness of manual versus electrical acupuncture. Finally, future research directions are suggested to better differentiate electrical from manual simulation, and implications for clinical practice are discussed.
Two-stage ditches represent an emerging management strategy in artificially drained agricultural landscapes that mimics natural floodplains and has the potential to improve water quality. We assessed the potential for the two-stage ditch to reduce sediment and nutrient export by measuring water column turbidity, nitrate (NO 3 À ), ammonium (NH 4 + ), and soluble reactive phosphorus (SRP) concentrations, and denitrification rates. During 2009-2010, we compared reaches with two-stage floodplains to upstream reaches with conventional trapezoid design in six agricultural streams. At base flow, these short two-stage reaches (<600 m) reduced SRP concentrations by 3-53%, but did not significantly reduce NO 3 À concentrations due to very high NO 3 À loads. The two-stage also decreased turbidity by 15-82%, suggesting reduced suspended sediment export during floodplain inundation. Reach-scale N-removal increased 3-24 fold during inundation due to increased bioreactive surface area with high floodplain denitrification rates. Inundation frequency varied with bench height, with lower benches being flooded more frequently, resulting in higher annual N-removal. We also found both soil organic matter and denitrification rates were higher on older floodplains. Finally, influence of the two-stage varied among streams and years due to variation in stream discharge, nutrient loads, and denitrification rates, which should be considered during implementation to optimize potential water quality benefits.
Symmetric laminar incompressible flow past a parabolic cylinder is considered for all Reynolds numbers. In the limit as the Reynolds number based on nose radius of curvature goes to zero, the solution for flow past a semi-infinite flat plate is obtained. All solutions are found by using an implicit alternating direction method to solve the time-dependent Navier-Stokes equations. The solutions found are compared with various other exact and approximate solutions. Results are presented for skin friction, surface pressure, friction drag and pressure drag. The numerical method developed is of particular interest since it combines the alternating direction method with the implicit method for solving the boundary-layer equations. This leads to fast convergence and may be of use in other problems.
Channelized streams are common in North American agricultural regions, where they minimize water residence time and biological nutrient processing. Floodplain restoration done via the 2-stage-ditch management strategy can improve channel stability and nutrient retention during storms. We examined the influence of floodplain restoration on whole-stream metabolism by measuring gross primary production (GPP) and ecosystem respiration (ER) for 1 y before and 4 y after restoration of an upstream, unaltered control reach and a downstream, restored reach. Both reaches were biologically active and dynamic. GPP ranged from 0.1 to 22.1 g O 2 m −2 d −1 , and ecosystem respiration (ER) rates ranged from −0.1 to −38.7 g O 2 m −2 d −1 . We used time-series analysis and found that GPP increased postrestoration during floodplain inundation when expressed per unit length, but not per unit area, of stream. GPP was more resilient post-than prerestoration and returned to prestorm levels more quickly after than before floodplain construction. In contrast, the floodplain restoration had no effect on ER or on any metric of metabolism during base flow. Overall, we showed that floodplainstream linkages can be important regulators of metabolism in restored agricultural streams.
Evidence indicates that cerebral blood flow is both increased and diminished in astronauts on return to Earth. Data from ground-based animal models simulating the effects of microgravity have shown that decrements in cerebral perfusion are associated with enhanced vasoconstriction and structural remodeling of cerebral arteries. Based on these results, the purpose of this study was to test the hypothesis that 13 d of spaceflight [Space Transportation System (STS)-135 shuttle mission] enhances myogenic vasoconstriction, increases medial wall thickness, and elicits no change in the mechanical properties of mouse cerebral arteries. Basilar and posterior communicating arteries (PCAs) were isolated from 9-wk-old female C57BL/6 mice for in vitro vascular and mechanical testing. Contrary to that hypothesized, myogenic vasoconstrictor responses were lower and vascular distensibility greater in arteries from spaceflight group (SF) mice (n=7) relative to ground-based control group (GC) mice (n=12). Basilar artery maximal diameter was greater in SF mice (SF: 236±9 μm and GC: 215±5 μm) with no difference in medial wall thickness (SF: 12.4±1.6 μm; GC: 12.2±1.2 μm). Stiffness of the PCA, as characterized via nanoindentation, was lower in SF mice (SF: 3.4±0.3 N/m; GC: 5.4±0.8 N/m). Collectively, spaceflight-induced reductions in myogenic vasoconstriction and stiffness and increases in maximal diameter of cerebral arteries signify that elevations in brain blood flow may occur during spaceflight. Such changes in cerebral vascular control of perfusion could contribute to increases in intracranial pressure and an associated impairment of visual acuity in astronauts during spaceflight.
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