In Situ Retention-Transport Response to Nitrate Loading and Storm Discharge in a Third-Order Stream

1990 ◽  
Vol 9 (3) ◽  
pp. 229-239 ◽  
Author(s):  
Frank J. Triska ◽  
Vance C. Kennedy ◽  
Ronald J. Avanzino ◽  
Gary W. Zellweger ◽  
Kenneth E. Bencala
Keyword(s):  
Third Order ◽  
Order Stream ◽  
Transport Response

Retention and Transport of Nutrients in a Third-Order Stream: Channel Processes

Ecology ◽  
1989 ◽  
Vol 70 (6) ◽  
pp. 1877-1892 ◽  
Author(s):  
Frank J. Triska ◽  
Vance C. Kennedy ◽  
Ronald J. Avanzino ◽  
Gary W. Zellweger ◽  
Kenneth E. Bencala
Keyword(s):  
Stream Channel ◽  
Channel Processes ◽  
Third Order ◽  
Order Stream

Physiological and pharmacological response of canine bronchial smooth muscle in situ

1983 ◽  
Vol 54 (1) ◽  
pp. 215-224 ◽  
Author(s):  
S. G. Hendrix ◽  
N. M. Munoz ◽  
A. R. Leff
Keyword(s):  
Smooth Muscle ◽  
Electrical Stimulation ◽  
Maximal Response ◽  
Repeated Injection ◽  
Third Order ◽  
Bronchial Smooth Muscle ◽  
Pure Nitrogen ◽  
Parasympathetic Ganglion ◽  
The Right

We studied the isometric response of bronchial smooth muscle in a single third-order bronchus of 24 dogs in situ. Length-tension studies were performed in six dogs by repeated injection of 10(-5) mol acetylcholine (ACh) into the right bronchoesophageal artery, and the resting tension (30.6 +/- 6.9 g/cm) and length (0.76 +/- 0.14 cm) permitting maximal contraction were determined. In eight other dogs, dose-related bronchial contraction was obtained with 10(-10) to 10(-5) mol intra-arterial (ia) ACh. Supramaximal electrical stimulation of the right cervical vagus nerve and bronchial parasympathetic ganglion stimulation with ia 1–1-dimethyl-4-phenylpiperazinium (DMPP) also caused bronchial contraction. The maximal response to ia ACh (28.5 +/- 1.7 g/cm), supramaximal electrical stimulation (15.2 +/- 1.1 g/cm), and ia DMPP (10.5 +/- 3.0 g/cm) was blocked by an ia dose of atropine (1–5 micrograms/kg) that did not alter the sympathetic relaxation response in the trachea. In four dogs, the bronchial response to sympathetic activation was studied by intravenous (iv) bolus injection of DMPP after cholinergic blockade with atropine. DMPP (25 micrograms/kg iv) caused 9.5 +/- 2.2 g/cm bronchial relaxation, which was blocked completely by 2–4 mg/kg iv propranolol. In six other dogs, hypoxia induced by ventilation with pure nitrogen caused bronchial contraction, which was blocked by vagotomy, atropine, and hexamethonium. We report a sensitive method for selective measurement of bronchial smooth muscle response in a single resistance bronchus. This preparation preserves regional innervation and circulation and permits selective physiological stimulation in situ.

scholarly journals Columnar modelling of nucleation burst evolution in the convective boundary layer – first results from a feasibility study Part II: Meteorological characterisation

2006 ◽  
Vol 6 (12) ◽  
pp. 4215-4230 ◽  
Author(s):  
O. Hellmuth
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Third Order ◽  
Convective Boundary ◽  
Large Eddy ◽  
Previous Hypothesis ◽  
Lidar Measurements ◽  
First Results ◽  
Model Setup

Abstract. While in Paper I of four papers a revised columnar high-order modelling approach to investigate gas-aerosol-turbulence interactions in the convective boundary layer (CBL) was deduced, in the present Paper II the model capability to predict the evolution of meteorological CBL parameters is demonstrated. Based on a model setup to simulate typical CBL conditions, predicted first-, second- and third-order moments were shown to agree very well with those obtained from in situ and remote sensing turbulence measurements such as aircraft, SODAR and LIDAR measurements as well as with those derived from ensemble-averaged large eddy simulations and wind tunnel experiments. The results show, that the model is able to predict the meteorological CBL parameters, required to verify or falsify, respectively, previous hypothesis on the interaction between CBL turbulence and new particle formation.

Arteriolar reactivity in lymphocyte-deficient mice

2011 ◽  
Vol 301 (4) ◽  
pp. H1276-H1285 ◽  
Author(s):  
Sean Leonard ◽  
B. Anne Croy ◽  
Coral L. Murrant
Keyword(s):  
B Cells ◽  
Nk Cells ◽  
Ang Ii ◽  
T And B Cells ◽  
Third Order ◽  
Immunodeficient Mice ◽  
Circulatory Control ◽  
Deficient Mice ◽  
Cell Cytokine Production

Mounting evidence suggests that lymphocytes have the capacity to contribute to the regulation of systemic circulatory control. We postulated that T and natural killer (NK) cells could modify basal microvascular activity under physiologically normal conditions. In situ intravital microscopy of mouse cremaster vasculature was used to evaluate arteriolar reactivities to the vasoconstrictors angiotensin II (ANG II) and phenylephrine (Phe) and the vasodilators acetylcholine (ACh) and adenosine (Ado) in normal [+/+; wild type (WT)] and genetically immunodeficient (T−B−NK+ or T−B−\NK−) C57BL/6 and BALB/c mice, strain backgrounds with differentially polarized T cell cytokine production. Immunodeficient mice tended to have smaller baseline and maximal diameters of third-order cremaster arterioles than their congenic WT partners. In C57BL/6, baseline diameters were similar in T-B− mice without or with NK cells; in BALB/c, baseline diameters were larger in T-B-NK− mice than in T−B−NK+ mice. Thus, at baseline, lymphocytes tended to promote vasodilation, except BALB/c NK cells, which mediated mild vasoconstriction. The presence of NK cells suppressed dilations to Ado in both strains, to ACh in the C57BL/6 strain, and dilatory responses to ANG II in C57BL/6 and to Phe in BALB/c. In the BALB/c strain, the presence of T and B cells promoted vasodilatory responses to Ado, attenuated dilations to low ACh concentrations, and exaggerated dilation and constriction responses to ANG II. Thus, under agonist challenge, NK cells generally promote constriction, whereas influences of T and B cells depend upon the stimulus. Therefore, lymphocytes or their products have physiological influences on microvascular arteriolar reactivity.

Diel Feeding and Positioning Periodicity of a Grazing Mayfly in a Trout Stream and a Fishless Stream

1994 ◽  
Vol 51 (2) ◽  
pp. 450-459 ◽  
Author(s):  
Cathy A. Cowan ◽  
Barbara L. Peckarsky
Keyword(s):  
Fish Predation ◽  
Third Order ◽  
Nocturnal Feeding ◽  
Western Colorado ◽  
Baetis Bicaudatus ◽  
Feeding Periodicity ◽  
Gut Fullness ◽  
Flow Through ◽  
Transplant Experiments

We studied the feeding and positioning periodicity on natural substrates of the overwintering and fast-growing summer generations of a grazing mayfly, Baetis bicaudatus, in a third-order trout stream and a fishless, first-order tributary in western Colorado. At 4-h intervals over 24-h, we recorded the number of Baetis on stone tops in flow-through enclosures in situ and in streamside circular flow-through chambers. We determined the feeding periodicity of Baetis using abundance of plant pigments as an index of gut fullness. Baetis were nocturnal in the trout stream; more animals were found on stone tops and guts were fuller at night, suggesting that individuals came to stone tops to feed during darkness. However, Baetis from the fishless stream were either aperiodic or weakly nocturnal. We tested the hypothesis that nocturnal feeding by Baetis is a response to the presence of visually feeding trout by conducting transplant experiments in the circular streams. After 24 h, Baetis transferred from the trout stream to fishless water remained strongly nocturnal, while Baetis transferred from the fishless stream to trout water became significantly more nocturnal, suggesting that the risk of fish predation outweighs the benefits of relaxing nocturnal periodicity to feed continuously.

scholarly journals Compressibility of the nitridosilicate SrYb[Si4N7] and the oxonitridoaluminosilicates MYb[Si4−x Al x O x N7−x] (x = 2; M = Sr, Ba)

2006 ◽  
Vol 62 (3) ◽  
pp. 424-430 ◽  
Author(s):  
E. A. Juarez-Arellano ◽  
A. Friedrich ◽  
K. Knorr ◽  
A. Lieb ◽  
B. Winkler ◽  
...  
Keyword(s):  
Minor Role ◽  
Third Order ◽  
X Ray ◽  
Compression Behaviour ◽  
Bulk Compressibility ◽  
Diamond Anvil ◽  
A Minor ◽  
Murnaghan Equation ◽  
Structurally Stable

The compressibilities of the nitridosilicate SrYb[Si4N7] and the oxonitridoaluminosilicates MYb[Si4−x Al x O x N7−x ] (x = 2; M = Sr, Ba) were investigated by in situ high-pressure X-ray powder diffraction. Pressures up to 42 GPa were generated using the diamond–anvil cell technique. The title compounds are structurally stable to the highest pressure obtained. A fit of a third-order Birch–Murnaghan equation-of-state to the p–V data results in V 0 = 302.91 (6) Å3, B 0 = 176 (2) GPa and B′ = 4.4 (2) for SrYb[Si4N7]; V 0 = 310.4 (1) Å3, B 0 = 161 (2) GPa and B′ = 4.6 (2) for SrYb[Si4−x Al x O x N7−x ]; and V 0 = 317.3 (5) Å3, B 0 = 168 (2) GPa and B′ = 4.7 (2) for BaYb[Si4−x Al x O x N7−x ]. While the linear compressibilities of the a and c axes of BaYb[Si4−x Al x O x N7−x ] are very similar up to 30 GPa, distinct differences were observed for SrYb[Si4N7] and SrYb[Si4−x Al x O x N7−x ], with the c axis being the most compressible axis. In all of the investigated compounds the bulk compressibility is dominated by the compression behaviour of the tetrahedral network, while the size of the substituted cation plays a minor role.

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