1,499 research outputs found
Decoupled above-and below ground responses to multi-decadal nitrogen and phosphorus amendments in two tundra ecosystems
Zinc Phosphide Residues in Gray-Tailed Voles (\u3ci\u3eMicrotus canicaudus\u3c/i\u3e) Fed Fixed Particles of a 2% Grain Bait
This study measured depelted-carcass residues of zinc phosphide (Zn3P2, CAS # 1314-84-7) in 8 (4 males and 4 females) gray-tailed voles (Microtus canicaudus). Six (3 males and 3 females) voles were confined individually in 1.89 dkl (5 gal) plastic pails that contained 5,2% Zn3P2 steamrolled- oat (SRO) groats; 2 voles (1 male and 1 female) served as analytical (unbaited) controls. Four test voles (3 males and 1female) died within 7.5 h after bait exposure; whereas, 2 test voles showed no signs of toxicosis and were euthanized 7.0 h after bait exposure. Whole carcasses were stored frozen and depelted carcasses were analyzed within 31 days for Zn3P2 residues using a acid-hydrolyzation, gas-chromatographic (GC) method. Analytical controls were euthanized, with carcasses stored and analyzed the same as test voles. A mean (± SD) 4.7 (±0.8) SRO groats were consumed by the test voles; this converted to a mean (±SD) intake of 2.15 (±0.38) mg Zn3P2 and dose of 73.25 mg/kg ( ± 22.95) Zn3P2. The mean (± SD) Zn3P2 residue in the 6 test vole carcasses was 0.42 mg (± 0.68); control carcasses contained \u3c0.009 mg Zn3P2- 3P2 in voles are variable, but typically \u3c 50% of ingested rodenticide and (2) risks of secondary poisoning posed by Zn3P2-baited voles to avian and mammalian predators/scavengers are low due to the relatively high toxic thresholds (\u3e 20 mg/kg) required to affect these species
Electromechanical Piezoresistive Sensing in Suspended Graphene Membranes
Monolayer graphene exhibits exceptional electronic and mechanical properties,
making it a very promising material for nanoelectromechanical (NEMS) devices.
Here, we conclusively demonstrate the piezoresistive effect in graphene in a
nano-electromechanical membrane configuration that provides direct electrical
readout of pressure to strain transduction. This makes it highly relevant for
an important class of nano-electromechanical system (NEMS) transducers. This
demonstration is consistent with our simulations and previously reported gauge
factors and simulation values. The membrane in our experiment acts as a strain
gauge independent of crystallographic orientation and allows for aggressive
size scalability. When compared with conventional pressure sensors, the sensors
have orders of magnitude higher sensitivity per unit area.Comment: 20 pages, 3 figure
4,5-Epoxide-1,6-dimethyl-1-vinylhexyl p-coumarate: A novel monoterpene derivative from Cleistopholis patens
A novel monoterpene derivative (1) and four known partially and total acetylated tri- and tetrarhamonoside dodecanyl ether derivatives: cleistrioside-2 (2) and cleistrioside-3 (3), cleistetroside-6 (4) and cleistetroside peracetate (5) have been isolated from the fruits of Cleistopholis patens. KEY WORDS: Cleistopholis patens, Annonaceae, Oligosaccharide, Partially acetylated tri- and tetrarhamnoside dodecanyl ether derivatives, Cleistrioside, Cleistetroside, Monoterpene derivative  Bull. Chem. Soc. Ethiop. 2003, 17(2), 177-180
Vision therapy manuals for adults and children
This adult Vision Therapy pamphlet is written for patients, parents, and educators. This pamphlet is intended to enhance the public\u27s awareness and understanding of the various aspects of Vision Therapy. We have comprised an in-depth description of Vision Therapy, explained certain visual skills, discussed visual hygiene, and included information about Vision Therapy for children, adults,and athletes. This Children\u27s Red/Green activity book is designed to educate a child from ages three to ten about various techniques and aspects of Vision Therapy. It is a story about a little boy who goes through Vision Therapy successfully. It is to be printed in red and is designed to be a fun anti-suppression activity if used with red/green glasses and a green pen. It is filled with activities such a dot to dots, mazes, coloring, and find it pages
Parametric equations for Shields parameter and wave orbital velocity in combined current and irregular waves
A fundamental requirement for any scour assessment and scour protection design is the ability
to determine the Shields parameter for combined wave and current conditions.
The Shields parameter can be calculated for current combined with monochromatic waves using the approach
of Soulsby (1997) in combination with the wave friction factor concept. For current in combination with irregular
waves, the same approach is suggested using a wave orbital velocity, Um, for representation of the irregular
sea state. Um is defined as 1.41 times the standard deviation of the near bed wave orbital velocity.
The Soulsby (2006) expression for Um is compared with a hyperbolic expression and validated using numerical
methods and laboratory measurements.
A large number of expressions exist for the wave friction factor as a function of relative bed roughness. From
a literature study, the paper proposes a combination of existing expressions to cover relative bed roughnesses
from sand over gravel to coarse armour rock
Carbon flux from decomposing wood and its dependency on temperature, wood N2 fixation rate, moisture and fungal composition in a Norway spruce forest
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Rewiring coral: Anthropogenic nutrients shift diverse coralâsymbiont nutrient and carbon interactions toward symbiotic algal dominance
Improving coral reef conservation requires heightened understanding of the mechanisms by which coral cope with changing environmental conditions to maintain optimal health. We used a longâterm (10 month) in situ experiment with two phylogenetically diverse scleractinians (Acropora palmata and Porites porites) to test how coralâsymbiotic algal interactions changed under realâworld conditions that were a priori expected to be beneficial (fishâmediated nutrients) and to be harmful, but nonâlethal, for coral (fish + anthropogenic nutrients). Analyzing nine response variables of nutrient stoichiometry and stable isotopes per coral fragment, we found that nutrients from fish positively affected coral growth, and moderate doses of anthropogenic nutrients had no additional effects. While growing, coral maintained homeostasis in their nutrient pools, showing tolerance to the different nutrient regimes. Nonetheless, structural equation models revealed more nuanced relationships, showing that anthropogenic nutrients reduced the diversity of coralâsymbiotic algal interactions and caused nutrient and carbon flow to be dominated by the symbiont. Our findings show that nutrient and carbon pathways are fundamentally ârewiredâ under anthropogenic nutrient regimes in ways that could increase coralsâ susceptibility to further stressors. We hypothesize that our experiment captured coral in a previously unrecognized transition state between mutualism and antagonism. These findings highlight a notable parallel between how anthropogenic nutrients promote symbiont dominance with the holobiont, and how they promote macroalgal dominance at the coral reef scale. Our findings suggest more realistic experimental conditions, including studies across gradients of anthropogenic nutrient enrichment as well as the incorporation of varied nutrient and energy pathways, may facilitate conservation efforts to mitigate coral loss.We provide a longâterm field experiment to test the implications of different nutrient sources, fish excretion and moderate levels of anthropogenic nutrients, for coral health and coralâsymbiont interactions. Our study identifies a potentially novel "transition state" whereby despite maintaining high growth rates and creating no apparent negative external effects, anthropogenic nutrient enrichment drives coralâalgal interactions to be dominated by the algal symbiontâthat is, increased prominence of energy and nutrient flow from the algal symbiont under conditions of Fish + anthropogenic nutrients (NPK) in the figure. We hypothesize that this ârewiringâ of the coralâsymbiont interactions may render the coral more vulnerable to additional stressors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162733/2/gcb15230_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162733/1/gcb15230.pd
Anthropogenic versus fishâderived nutrient effects on seagrass community structure and function
Humans are altering nutrient dynamics through myriad pathways globally. Concurrent with the addition of nutrients via municipal, industrial, and agricultural sources, widespread consumer exploitation is changing consumerâmediated nutrient dynamics drastically. Thus, altered nutrient dynamics can occur through changes in the supply of multiple nutrients, as well as through changes in the sources of these nutrients. Seagrass ecosystems are heavily impacted by human activities, with highly altered nutrient dynamics from multiple causes. We simulate scenarios of altered nutrient supply and ratios, nitrogen:phosphorus (N:P), from two nutrient sources in seagrass ecosystems: anthropogenic fertilizer and fish excretion. In doing so we tested expectations rooted in ecological theory that suggest the importance of resource dynamics for predicting primary producer dynamics. Ecosystem functions were strongly altered by artificial fertilizer (e.g., seagrass growth increased by as much as 140%), whereas plant/algae community structure was most affected by fishâmediated nutrients or the interaction of both treatments (e.g., evenness increased by ~140% under conditions of low fish nutrients and high anthropogenic nutrients). Interactions between the nutrient sources were found for only two of six response variables, and the ratio of nutrient supply was the best predictor for only one response. These findings show that seagrass structure and function are well predicted by supply of a single nutrient (either N or P). Importantly, no single nutrient best explained the majority of responsesâmeasures of community structure were best explained by the primary limiting nutrient to this system (P), whereas measures of growth and density of the dominant producer in the system were best explained by N. Thus, while our findings support aspects of theoretical expectations, the complexity of producer community responses belies broad generalities, underscoring the need to manage for multiple simultaneous nutrients in these imperiled coastal ecosystems.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145341/1/ecy2388_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145341/2/ecy2388-sup-0003-AppendixS3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145341/3/ecy2388-sup-0005-AppendixS5.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145341/4/ecy2388-sup-0006-AppendixS6.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145341/5/ecy2388-sup-0001-AppendixS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145341/6/ecy2388-sup-0002-AppendixS2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145341/7/ecy2388.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145341/8/ecy2388-sup-0004-AppendixS4.pd
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