Arboreal seed removal and insect damage in three California oaks

Treesearch

Walter D. Koenig; Johannes M. H. Knops; William J. Carmen

2002-01-01

We investigated arboreal removal and insect damage to acorns in an undisturbed oak woodland in central coastal California. Arboreal seed removal was determined for four to eight individual Quercus lobata trees over a period of 14 years by comparing visual estimates of the acorn crop with the number of acorns caught in seed traps. Insect damage was...

Action potentials reliably invade axonal arbors of rat neocortical neurons

PubMed Central

Cox, Charles L.; Denk, Winfried; Tank, David W.; Svoboda, Karel

2000-01-01

Neocortical pyramidal neurons have extensive axonal arborizations that make thousands of synapses. Action potentials can invade these arbors and cause calcium influx that is required for neurotransmitter release and excitation of postsynaptic targets. Thus, the regulation of action potential invasion in axonal branches might shape the spread of excitation in cortical neural networks. To measure the reliability and extent of action potential invasion into axonal arbors, we have used two-photon excitation laser scanning microscopy to directly image action-potential-mediated calcium influx in single varicosities of layer 2/3 pyramidal neurons in acute brain slices. Our data show that single action potentials or bursts of action potentials reliably invade axonal arbors over a range of developmental ages (postnatal 10–24 days) and temperatures (24°C-30°C). Hyperpolarizing current steps preceding action potential initiation, protocols that had previously been observed to produce failures of action potential propagation in cultured preparations, were ineffective in modulating the spread of action potentials in acute slices. Our data show that action potentials reliably invade the axonal arbors of neocortical pyramidal neurons. Failures in synaptic transmission must therefore originate downstream of action potential invasion. We also explored the function of modulators that inhibit presynaptic calcium influx. Consistent with previous studies, we find that adenosine reduces action-potential-mediated calcium influx in presynaptic terminals. This reduction was observed in all terminals tested, suggesting that some modulatory systems are expressed homogeneously in most terminals of the same neuron. PMID:10931955

Population-scale three-dimensional reconstruction and quantitative profiling of microglia arbors

PubMed Central

Rey-Villamizar, Nicolas; Merouane, Amine; Lu, Yanbin; Mukherjee, Amit; Trett, Kristen; Chong, Peter; Harris, Carolyn; Shain, William; Roysam, Badrinath

2015-01-01

Motivation: The arbor morphologies of brain microglia are important indicators of cell activation. This article fills the need for accurate, robust, adaptive and scalable methods for reconstructing 3-D microglial arbors and quantitatively mapping microglia activation states over extended brain tissue regions. Results: Thick rat brain sections (100–300 µm) were multiplex immunolabeled for IBA1 and Hoechst, and imaged by step-and-image confocal microscopy with automated 3-D image mosaicing, producing seamless images of extended brain regions (e.g. 5903 × 9874 × 229 voxels). An over-complete dictionary-based model was learned for the image-specific local structure of microglial processes. The microglial arbors were reconstructed seamlessly using an automated and scalable algorithm that exploits microglia-specific constraints. This method detected 80.1 and 92.8% more centered arbor points, and 53.5 and 55.5% fewer spurious points than existing vesselness and LoG-based methods, respectively, and the traces were 13.1 and 15.5% more accurate based on the DIADEM metric. The arbor morphologies were quantified using Scorcioni’s L-measure. Coifman’s harmonic co-clustering revealed four morphologically distinct classes that concord with known microglia activation patterns. This enabled us to map spatial distributions of microglial activation and cell abundances. Availability and implementation: Experimental protocols, sample datasets, scalable open-source multi-threaded software implementation (C++, MATLAB) in the electronic supplement, and website (www.farsight-toolkit.org). http://www.farsight-toolkit.org/wiki/Population-scale_Three-dimensional_Reconstruction_and_Quanti-tative_Profiling_of_Microglia_Arbors Contact: broysam@central.uh.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25701570

Philodryas chamissonis (Reptilia: Squamata: Colubridae) preys on the arboreal marsupial Dromiciops gliroides (Mammalia: Microbiotheria: Microbiotheriidae).

PubMed

Muñoz-Leal, S; Ardiles, K; Figueroa, R A; González-Acuña, D

2013-02-01

Philodryas chamissonis, the Chilean long-tailed snake, is a diurnal predator mainly of Liolaemus lizards, but also of amphibians, birds, rodents and juvenile rabbits. Dromiciops gliroides (Colocolo opossum) is an arboreal marsupial endemic of temperate rainforest of southern South America. Little information is available about this marsupial's biology and ecology. Here we report the predation of one Colocolo opossum by an adult female P. chamissonis in a mixed Nothofagus forest, composed mainly by N. dombeyi, N. glauca and N. alpina trees, in the "Huemules de Niblinto" National Reserve, Nevados de Chillán, Chile. Since these two species have different activity and habitat use patterns, we discuss how this encounter may have occurred. Although it could just have been an opportunistic event, this finding provides insights into the different components of food chains in forest ecosystems of Chile.

Blood vessel adaptation to gravity in a semi-arboreal snake

NASA Technical Reports Server (NTRS)

Conklin, D. J.; Lillywhite, H. B.; Olson, K. R.; Ballard, R. E.; Hargens, A. R.

1996-01-01

The effects of vasoactive agonists on systemic blood vessels were examined with respect to anatomical location and gravity acclimation in the semi-arboreal snake, Elaphe Obsoleta. Major blood vessels were reactive to putative neurotransmitters, hormones or local factors in vessel specific patterns. Catecholamines, adenosine triphosphate, histamine and high potassium (80 mM) stimulated significantly greater tension per unit vessel mass in posterior than anterior arteries. Anterior vessels were significantly more sensitive to catecholamines than midbody and posterior vessels. Angiotensin II stimulated significantly greater tension in carotid artery than in midbody and posterior dorsal aorta. Arginine vasotocin strongly contracted the left and right aortic arches and anterior dorsal aorta. Veins were strongly contracted by catecholamines, high potassium and angiotensin II, but less so by adenosine triphosphate, arginine vasotocin and histamine. Precontracted vessel were relaxed by acetylcholine and sodium nitroprusside, but not by atrial natriuretic peptide or bradykinin. Chronic exposure of snakes to intermittent hypergravity stress ( + 1.5 Gz at tail) did not affect the majority of vessel responses. These data demonstrate that in vitro tension correlates with that catecholamines, as well as other agonists, are important in mediating vascular responses to gravitational stresses in snakes.

Hand pressures during arboreal locomotion in captive bonobos (Pan paniscus).

PubMed

Samuel, Diana S; Nauwelaerts, Sandra; Stevens, Jeroen M G; Kivell, Tracy L

2018-04-19

Evolution of the human hand has undergone a transition from use during locomotion to use primarily for manipulation. Previous comparative morphological and biomechanical studies have focused on potential changes in manipulative abilities during human hand evolution, but few have focused on functional signals for arboreal locomotion. Here, we provide this comparative context though the first analysis of hand loading in captive bonobos during arboreal locomotion. We quantify pressure experienced by the fingers, palm and thumb in bonobos during vertical locomotion, suspension and arboreal knuckle-walking. The results show that pressure experienced by the fingers is significantly higher during knuckle-walking compared with similar pressures experienced by the fingers and palm during suspensory and vertical locomotion. Peak pressure is most often experienced at or around the third digit in all locomotor modes. Pressure quantified for the thumb is either very low or absent, despite the thumb making contact with the substrate during all suspensory and vertical locomotor trials. Unlike chimpanzees, bonobos do not show a rolling pattern of digit contact with the substrate during arboreal knuckle-walking - instead, we found that digits 3 and 4 typically touch down first and digit 5 almost always made contact with the substrate. These results have implications for interpreting extant and fossilized hand morphology; we expect bonobo (and chimpanzee) bony morphology to primarily reflect the biomechanical loading of knuckle-walking, while functional signals for arboreal locomotion in fossil hominins are most likely to appear in the fingers, particularly digit 3, and least likely to appear in the morphology of the thumb. © 2018. Published by The Company of Biologists Ltd.

Physiological and behavioral responses of an arboreal mammal to smoke and charcoal-ash substrate.

PubMed

Nowack, Julia; Stawski, Clare; Körtner, Gerhard; Geiser, Fritz

2018-02-01

The recent observation that torpor plays a key role in post-fire survival has been mainly attributed to the reduced food resources after fires. However, some of these adjustments can be facilitated or amplified by environmental changes associated with fires, such as the presence of a charcoal-ash substrate. In a previous experiment on a small terrestrial mammal the presence of charcoal and ash linked to food restriction intensified torpor use. However, whether fire cues also act as a trigger of torpor use when food is available and whether they affect other species including arboreal mammals remains elusive. To evaluate whether smoke, charcoal and ash can act as proximate triggers for an impending period of food shortage requiring torpor for mammals, we conducted an experiment on captive sugar gliders (Petaurus breviceps), a small, arboreal marsupial, housed in outside aviaries under different food regimes and natural ambient conditions. When food was available, fire simulation via exposure to smoke and charcoal-ash substrate caused a significant earlier start of activity and a significant decrease in resting body temperature. In contrast, only when food was withheld, did smoke and charcoal-ash exposure significantly enhance torpor depth and duration. Thus, our study not only provides evidence that fire simulation does affect arboreal and terrestrial species similarly, but also suggests that smoke and ash were presumably selected as cues for torpor induction because they indicate an impending lack of food. Copyright © 2017 Elsevier Inc. All rights reserved.

Lizard tail regeneration as an instructive model of enhanced healing capabilities in an adult amniote.

PubMed

Lozito, Thomas P; Tuan, Rocky S

2017-03-01

The ability to regenerate damaged or lost tissues has remained the lofty goal of regenerative medicine. Unfortunately, humans, like most mammals, suffer from very minimal natural regenerative capabilities. Certain non-mammalian animal species, however, are not so limited in their healing capabilities, and several have attracted the attention of researchers hoping to recreate enhanced healing responses in humans. This review focuses on one such animal group with remarkable regenerative abilities, the lizards. As the closest relatives of mammals that exhibit enhanced regenerative abilities as adults, lizards potentially represent the most relevant model for direct comparison and subsequent improvement of mammalian healing. Lizards are able to regenerate amputated tails and exhibit adaptations that both limit tissue damage in response to injury and initiate coordinated regenerative responses. This review summarizes the salient aspects of lizard tail regeneration as they relate to the overall regenerative process and also presents the relevant information pertaining to regrowth of specific tissues, including skeletal, muscular, nervous, and vascular tissues. The goal of this review is to introduce the topic of lizard tail regeneration to new audiences with the hope of expanding the knowledge base of this underutilized but potentially powerful model organism.

Aneides ferreus (clouded salamander): arboreal activity

Treesearch

William W. Price; Clinton P. Landon; Eric D. Forsman

2010-01-01

Aneides ferreus (clouded salamander) inhabits the forests of western Oregon and extreme northwestern California. Although thought to be primarily terrestrial, A. ferreus has occasionally been found as high as 60 m up in trees and two recent reports suggest that it may be more arboreal than previously believed. However, it is...

Forelimb bone curvature in terrestrial and arboreal mammals

PubMed Central

Henderson, Keith; Pantinople, Jess; McCabe, Kyle; Milne, Nick

2017-01-01

It has recently been proposed that the caudal curvature (concave caudal side) observed in the radioulna of terrestrial quadrupeds is an adaptation to the habitual action of the triceps muscle which causes cranial bending strains (compression on cranial side). The caudal curvature is proposed to be adaptive because longitudinal loading induces caudal bending strains (increased compression on the caudal side), and these opposing bending strains counteract each other leaving the radioulna less strained. If this is true for terrestrial quadrupeds, where triceps is required for habitual elbow extension, then we might expect that in arboreal species, where brachialis is habitually required to maintain elbow flexion, the radioulna should instead be cranially curved. This study measures sagittal curvature of the ulna in a range of terrestrial and arboreal primates and marsupials, and finds that their ulnae are curved in opposite directions in these two locomotor categories. This study also examines sagittal curvature in the humerus in the same species, and finds differences that can be attributed to similar adaptations: the bone is curved to counter the habitual muscle action required by the animal’s lifestyle, the difference being mainly in the distal part of the humerus, where arboreal animals tend have a cranial concavity, thought to be in response the carpal and digital muscles that pull cranially on the distal humerus. PMID:28462036

Developing neurons use a putative pioneer's peripheral arbor to establish their terminal fields.

PubMed

Gan, W B; Macagno, E R

1995-05-01

Pioneer neurons are known to guide later developing neurons during the initial phases of axonal outgrowth. To determine whether they are also important in the formation of terminal fields by the follower cells, we studied the role of a putative leech pioneer neuron, the pressure-sensitive (PD) neuron, in the establishment of other neurons' peripheral arbors. The PD neuron has a major axon that exits from its segmental ganglion to grow along the dorsal-posterior (DP) nerve to the dorsal body wall, where it arborizes extensively mainly in its own segment. It also has two minor axons that project to the two adjacent segments but branch to a lesser degree. We found that the peripheral projections of several later developing neurons, including the AP motor neuron and the TD sensory neuron, followed, with great precision, the major axon and peripheral arbor of the consegmental PD neuron, up to its fourth-order branches. When a PD neuron was ablated before it had grown to the body wall, the AP and TD axons grew normally toward and reached the target area, but then formed terminal arbors that were greatly reduced in size and abnormal in morphology. Further, if the ablation of a PD neuron was accompanied by the induction, in the same segment, of greater outgrowth of the minor axon of a PD neuron from the adjacent segment, the arbors of the same AP neurons grew along these novel PD neuron branches. These results demonstrate that the peripheral arbor of a PD neuron is a both necessary and sufficient template for the formation of normal terminal fields by certain later growing follower neurons.

Methods for measuring populations of arboreal rodents.

Treesearch

Andrew B. Carey; Brian L. Biswell; Joseph W. Witt

1991-01-01

Three arboreal rodents are sensitive indicators of forest ecosystem function in the Pacific Northwest. The northern flying squirrel (Glaucomys sabrinus) is mycophagous, cavity-nesting, and a major prey of the spotted owl (Strix occidentalis). The red tree vole (Phenacomys longicaudus) is restricted to trees...

H3 Histone Tail Conformation within the Nucleosome and the Impact of K14 Acetylation Studied Using Enhanced Sampling Simulation

PubMed Central

Ikebe, Jinzen; Sakuraba, Shun; Kono, Hidetoshi

2016-01-01

Acetylation of lysine residues in histone tails is associated with gene transcription. Because histone tails are structurally flexible and intrinsically disordered, it is difficult to experimentally determine the tail conformations and the impact of acetylation. In this work, we performed simulations to sample H3 tail conformations with and without acetylation. The results show that irrespective of the presence or absence of the acetylation, the H3 tail remains in contact with the DNA and assumes an α-helix structure in some regions. Acetylation slightly weakened the interaction between the tail and DNA and enhanced α-helix formation, resulting in a more compact tail conformation. We inferred that this compaction induces unwrapping and exposure of the linker DNA, enabling DNA-binding proteins (e.g., transcription factors) to bind to their target sequences. In addition, our simulation also showed that acetylated lysine was more often exposed to the solvent, which is consistent with the fact that acetylation functions as a post-translational modification recognition site marker. PMID:26967163

Maximization of the connectivity repertoire as a statistical principle governing the shapes of dendritic arbors

PubMed Central

Wen, Quan; Stepanyants, Armen; Elston, Guy N.; Grosberg, Alexander Y.; Chklovskii, Dmitri B.

2009-01-01

The shapes of dendritic arbors are fascinating and important, yet the principles underlying these complex and diverse structures remain unclear. Here, we analyzed basal dendritic arbors of 2,171 pyramidal neurons sampled from mammalian brains and discovered 3 statistical properties: the dendritic arbor size scales with the total dendritic length, the spatial correlation of dendritic branches within an arbor has a universal functional form, and small parts of an arbor are self-similar. We proposed that these properties result from maximizing the repertoire of possible connectivity patterns between dendrites and surrounding axons while keeping the cost of dendrites low. We solved this optimization problem by drawing an analogy with maximization of the entropy for a given energy in statistical physics. The solution is consistent with the above observations and predicts scaling relations that can be tested experimentally. In addition, our theory explains why dendritic branches of pyramidal cells are distributed more sparsely than those of Purkinje cells. Our results represent a step toward a unifying view of the relationship between neuronal morphology and function. PMID:19622738

Bacillus pumilus ES4: candidate plant growth-promoting bacterium to enhance establishment of plants in mine tailings

PubMed Central

de-Bashan, Luz E.; Hernandez, Juan-Pablo; Bashan, Yoav; Maier, Raina

2014-01-01

Three plant growth-promoting bacteria (PGPB; Bacillus pumilus ES4, B. pumilus RIZO1, and Azospirillum brasilense Cd) were tested for their ability to enhance plant growth and development of the native Sonoran Desert shrub quailbush (Atriplex lentiformis) and for their effect on the native bacterial community in moderately acidic, high-metal content (AHMT) and in neutral, low metal content natural tailings (NLMT) in controlled greenhouse experiments. Inoculation of quailbush with all three PGPB significantly enhanced plant growth parameters, such as germination, root length, dry weight of shoots and roots, and root/shoot ratio in both types of tailings. The effect of inoculation on the indigenous bacterial community by the most successful PGPB Bacillus pumilus ES4 was evaluated by denaturating gradient gel electrophoresis (PCR-DGGE) fingerprinting and root colonization was followed by specific fluorescent in situ hybridization (FISH). Inoculation with this strain significantly changed the bacterial community over a period of 60 days. FISH analysis showed that the preferred site of colonization was the root tips and root elongation area. This study shows that inoculation of native perennial plants with PGPB can be used for developing technologies for phytostabilizing mine tailings. PMID:25009362

Detection of Mercury's Potassium Tail

NASA Astrophysics Data System (ADS)

Schmidt, Carl; Leblanc, Francois; Moore, Luke; Bida, Thomas A.

2017-10-01

Ground-based observations of Mercury's exosphere bridge the gap between the MESSENGER and BepiColombo missions and provide a broad counterpart to their in situ measurements. Here we report the first detection of Mercury's potassium tail in both emission lines of the D doublet. The sodium to potassium abundance ratio at 5 planetary radii down-tail is approximately 95, near the mid-point of a wide range of values that have been quoted over the planet's disk. This is several times the Na/K present in atmospheres of the Galilean satellites and more than an order of magnitude above Mercury's usual analogue, the Moon. The observations confirm that Mercury's anomalously high Na/K ratios cannot be explained by differences in neutral loss rates. The width and structure of the Na and K tails is comparable and both exhibit a persistent enhancement in their northern lobe. We interpret this as a signature of Mercury's offset magnetosphere; the exosphere's source rates are locally enhanced at the southern surface, and sloshing from radiation pressure and gravity guides this population into the northern region of the tail.

[Photosynthetic characteristics of five arbor species in Shenyang urban area].

PubMed

Li, Hai-Me; He, Xing-Yuan; Wang, Kui-Ling; Chen, Wei

2007-08-01

By using LI-6400 infrared gas analyzer, this paper studied the diurnal and seasonal variations of the photosynthetic rate of main arbor species (Populus alba x P. berolinensis, Salix matsudana, Ulmus pumila, Robinia pseudoacacia and Prunus davidiana) in Shenyang urban area. The correlations between net photosynthetic rate and environmental factors (photosynthetic active radiation, temperature, and stomatal conductance) were assessed by multivariate regression analysis, and related equations were constructed. The results showed that for test arbor species, the diurnal variation of photosynthetic rate mainly presented a single peak curve, and the seasonal variation was in the order of summer > autumn > spring. The major factors affecting the photosynthetic rate were photosynthetic active radiation, stomatal conductance, and intercellular CO2 concentration.

Enhancement of basolateral amygdaloid neuronal dendritic arborization following Bacopa monniera extract treatment in adult rats.

PubMed

Vollala, Venkata Ramana; Upadhya, Subramanya; Nayak, Satheesha

2011-01-01

In the ancient Indian system of medicine, Ayurveda, Bacopa monniera is classified as Medhya rasayana, which includes medicinal plants that rejuvenate intellect and memory. Here, we investigated the effect of a standardized extract of Bacopa monniera on the dendritic morphology of neurons in the basolateral amygdala, a region that is concerned with learning and memory. The present study was conducted on 2½-month-old Wistar rats. The rats were divided into 2-, 4- and 6-week treatment groups. Rats in each of these groups were further divided into 20 mg/kg, 40 mg/kg and 80 mg/kg dose groups (n = 8 for each dose). After the treatment period, treated rats and age-matched control rats were subjected to spatial learning (T-maze) and passive avoidance tests. Subsequently, these rats were killed by decapitation, the brains were removed, and the amygdaloid neurons were impregnated with silver nitrate (Golgi staining). Basolateral amygdaloid neurons were traced using camera lucida, and dendritic branching points (a measure of dendritic arborization) and dendritic intersections (a measure of dendritic length) were quantified. These data were compared with the data from the age-matched control rats. The results showed an improvement in spatial learning performance and enhanced memory retention in rats treated with Bacopa monniera extract. Furthermore, a significant increase in dendritic length and the number of dendritic branching points was observed along the length of the dendrites of the basolateral amygdaloid neurons of rats treated with 40 mg/kg and 80 mg/kg of Bacopa monniera (BM) for longer periods of time (i.e., 4 and 6 weeks). We conclude that constituents present in Bacopa monniera extract have neuronal dendritic growth-stimulating properties.

7. EXTERIOR, SIDE VIEW FROM GARDEN SHOWING GRAPE ARBOR undated ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. EXTERIOR, SIDE VIEW FROM GARDEN SHOWING GRAPE ARBOR undated - Jean Baptiste Valle House, 99 South Main Street (Northwest corner of Main & Market Streets), Sainte Genevieve, Ste. Genevieve County, MO

The biology of arboreal rodents in Douglas-fir forests.

Treesearch

Andrew B. Carey

1991-01-01

Arboreal rodents in Douglas-fir forests west of the Cascade crest in Oregon and Washington include (listed in decreasing order of dependence on trees) red tree vole (Phenacomys longicaucfus), northern flying squirrel (Glaucomys sabrinus), Douglas' squirrel (Tamiasciurus douglasii), dusky-footed woodrat...

Recycling of asbestos tailings used as reinforcing fillers in polypropylene based composites.

PubMed

Zhai, Wensi; Wang, Yao; Deng, Yuan; Gao, Hongli; Lin, Zhen; Li, Mao

2014-04-15

In this work, asbestos tailings were recycled and used as reinforcing fillers to enhance the mechanical properties of polypropylene (PP). A silane coupling agent was used to chemically modify the asbestos tailings to increase the compatibility between asbestos tailings and polypropylene matrix. Both raw and chemically treated asbestos tailings with different loading levels (from 3 to 30 wt%) were utilized to fabricate composites. Mechanical properties of these composites have been investigated by dynamic mechanical analysis, tensile test and notched impact test. Results showed that hybridization of asbestos tailings in the composites enhanced the mechanical properties of neat PP evidently, and treated asbestos tailings/PP composites yielded even better mechanical properties compared with those of raw asbestos tailings/PP composites. This recycling method of asbestos tailings not only reduces disposal costs and avoids secondary pollution but also produces a new PP-based composite material with enhanced mechanical properties. Copyright © 2014 Elsevier B.V. All rights reserved.

Interactions of Northwest forest canopies and arboreal mammals.

Treesearch

A.B. Carey

1996-01-01

The interactions among Northwest forest canopies and the mammals that inhabit them have been poorly studied. My purpose was to identify interactions among arboreal mammals and canopies that have implications for managers seeking to conserve biodiversity in the Pacific Northwest. I constructed a comprehensive, but parsimonious list of canopy attributes that could be...

22. MEADOW, LOOKING EAST WITH STREAM ARBOR ON RIGHT Photocopy ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. MEADOW, LOOKING EAST WITH STREAM ARBOR ON RIGHT Photocopy of photograph, 1930s National Park Service, National Capital Region files - Dumbarton Oaks Park, Thirty-second & R Streets Northwest, Washington, District of Columbia, DC

Enhancement of basolateral amygdaloid neuronal dendritic arborization following Bacopa monniera extract treatment in adult rats

PubMed Central

Vollala, Venkata Ramana; Upadhya, Subramanya; Nayak, Satheesha

2011-01-01

OBJECTIVE: In the ancient Indian system of medicine, Ayurveda, Bacopa monniera is classified as Medhya rasayana, which includes medicinal plants that rejuvenate intellect and memory. Here, we investigated the effect of a standardized extract of Bacopa monniera on the dendritic morphology of neurons in the basolateral amygdala, a region that is concerned with learning and memory. METHODS: The present study was conducted on 2½-month-old Wistar rats. The rats were divided into 2-, 4- and 6-week treatment groups. Rats in each of these groups were further divided into 20 mg/kg, 40 mg/kg and 80 mg/kg dose groups (n  =  8 for each dose). After the treatment period, treated rats and age-matched control rats were subjected to spatial learning (T-maze) and passive avoidance tests. Subsequently, these rats were killed by decapitation, the brains were removed, and the amygdaloid neurons were impregnated with silver nitrate (Golgi staining). Basolateral amygdaloid neurons were traced using camera lucida, and dendritic branching points (a measure of dendritic arborization) and dendritic intersections (a measure of dendritic length) were quantified. These data were compared with the data from the age-matched control rats. RESULTS: The results showed an improvement in spatial learning performance and enhanced memory retention in rats treated with Bacopa monniera extract. Furthermore, a significant increase in dendritic length and the number of dendritic branching points was observed along the length of the dendrites of the basolateral amygdaloid neurons of rats treated with 40 mg/kg and 80 mg/kg of Bacopa monniera (BM) for longer periods of time (i.e., 4 and 6 weeks). CONCLUSION: We conclude that constituents present in Bacopa monniera extract have neuronal dendritic growth-stimulating properties. PMID:21655763

Dauer-specific dendrite arborization in C. elegans is regulated by KPC-1/Furin.

PubMed

Schroeder, Nathan E; Androwski, Rebecca J; Rashid, Alina; Lee, Harksun; Lee, Junho; Barr, Maureen M

2013-08-19

Dendrites often display remarkably complex and diverse morphologies that are influenced by developmental and environmental cues. Neuroplasticity in response to adverse environmental conditions entails both hypertrophy and resorption of dendrites. How dendrites rapidly alter morphology in response to unfavorable environmental conditions is unclear. The nematode Caenorhabditis elegans enters into a stress-resistant dauer larval stage in response to an adverse environment. Here we show that the IL2 bipolar sensory neurons undergo dendrite arborization and axon remodeling during dauer development. When dauer larvae are returned to favorable environmental conditions, animals resume reproductive development and IL2 dendritic branches retract, leaving behind remnant branches in postdauer L4 and adult animals. The C. elegans furin homolog KPC-1 is required for dauer IL2 dendritic arborization and dauer-specific nictation behavior. KPC-1 is also necessary for dendritic arborization of PVD and FLP sensory neurons. In mammals, furin is essential, ubiquitously expressed, and associated with numerous pathologies, including neurodegenerative diseases. While broadly expressed in C. elegans neurons and epithelia, KPC-1 acts cell autonomously in IL2 neurons to regulate dauer-specific dendritic arborization and nictation. Neuroplasticity of the C. elegans IL2 sensory neurons provides a paradigm to study stress-induced and reversible dendritic branching, and the role of environmental and developmental cues in this process. The newly discovered role of KPC-1 in dendrite morphogenesis provides insight into the function of proprotein convertases in nervous system development. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ecological aspects of microorganisms inhabiting uranium mill tailings

USGS Publications Warehouse

Miller, C.L.; Landa, E.R.; Updegraff, D.M.

1987-01-01

Numbers and types of microorganisms in uranium mill tailings were determined using culturing techniques. Arthrobacter were found to be the predominant microorganism inhabiting the sandy tailings, whereas Bacillus and fungi predominated in the slime tailings. Sulfate-reducing bacteria, capable of leaching radium, were isolated in low numbers from tailings samples but were isolated in significantly high numbers from topsoil in contact with the tailings. The results are placed in the context of the magnitude of uranium mill tailings in the United States, the hazards posed by the tailings, and how such hazards could be enhanced or diminished by microbial activities. Patterns in the composition of the microbial population are evaluated with respect to the ecological variables that influence microbial growth. ?? 1987 Springer-Verlag New York Inc.

20. STREAM ARBOR, LOOKING NORTHWEST Photocopy of photograph, 1930s National ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. STREAM ARBOR, LOOKING NORTHWEST Photocopy of photograph, 1930s National Park Service, National Capital Region files - Dumbarton Oaks Park, Thirty-second & R Streets Northwest, Washington, District of Columbia, DC

Late-Night Shared-Ride Taxi Transit in Ann Arbor, MI

DOT National Transportation Integrated Search

1984-10-01

The Ann Arbor Transportation Authority introduced Night Ride, a late-night shared-ride taxi transit service, in mid-March 1982. The service was provided through a contract with a local taxicab company and funded through a demonstration grant from the...

Flapping foil power generator performance enhanced with a spring-connected tail

NASA Astrophysics Data System (ADS)

Liu, Zhengliang; Tian, Fang-Bao; Young, John; Lai, Joseph C. S.

2017-12-01

The flexibility effects on the performance of a flapping foil power generator are numerically studied by using the immersed boundary-lattice Boltzmann method at a Reynolds number of 1100. The flapping foil system consists of a rigid NACA0015 foil undergoing harmonic pitch and plunge motions and a passively actuated flat plate pinned to the trailing edge of the rigid foil. The flexibility is modeled by a torsional spring model at the conjuncture of the rigid foil and the tail. Here, a parametric study on mass density and natural frequency is conducted under the optimum kinematic condition of the rigid system identified from the literature and numerical simulations made for reduced frequency f* = 0.04-0.24 and pitch amplitude θ0 = 40°-90°. Four typical cases are discussed in detail by considering time histories of hydrodynamic loads and tail deformations under the optimal and non-optimal kinematic conditions. Results show that under the rigid-system optimal kinematic condition, a tail with appropriate mass density (μ = 0.60) and resonant frequency ( fr*=1.18 ) can improve the maximum efficiency by 7.24% accompanied by an increase of 6.63% in power compared to those of a rigid foil with a rigid tail. This is because the deflection of the tail reduces the low pressure region on the pressure surface (i.e., the lower surface during the upstroke or the upper surface during the downstroke) caused by the leading edge vortex after the stroke reversal, resulting in a higher efficiency. At high flapping frequencies, a spring-connected tail ( fr*=0.13 ) eliminates the large spike in the moment observed in high stiffness cases, reducing the power required for the pitch motion, resulting in 117% improvement in efficiency over that with a rigid tail at a reduced frequency of 0.24.

TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knierman, Karen A.; Scowen, Paul; Veach, Todd

2013-09-10

The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio {approx}4: 1 occurring {approx}200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun. However, deep UBVR and H{alpha} narrowband images show evidence of recent star formation in the western tail, though it lacks massive star clusters and cluster complexes. Using Herschel PACS spectroscopy, we discover 158 {mu}m [C II] emission at themore » location of the three most luminous H{alpha} sources in the eastern tail, but not at the location of the even brighter H{alpha} source in the western tail. The western tail is found to have a normal star formation efficiency (SFE), but the eastern tail has a low SFE. The lack of CO and [C II] emission suggests that the western tail H II region may have a low carbon abundance and be undergoing its first star formation. The western tail is more efficient at forming stars, but lacks massive clusters. We propose that the low SFE in the eastern tail may be due to its formation as a splash region where gas heating is important even though it has sufficient molecular and neutral gas to make massive star clusters. The western tail, which has lower gas surface density and does not form high-mass star clusters, is a tidally formed region where gravitational compression likely enhances star formation.« less

Plant Growth-Promoting Bacteria for Phytostabilization of Mine Tailings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grandlic, C.J.; Mendez, M.O.; Chorover, J.

2009-05-19

Eolian dispersion of mine tailings in arid and semiarid environments is an emerging global issue for which economical remediation alternatives are needed. Phytostabilization, the revegetation of these sites with native plants, is one such alternative. Revegetation often requires the addition of bulky amendments such as compost which greatly increases cost. We report the use of plant growth-promoting bacteria (PGPB) to enhance the revegetation of mine tailings and minimize the need for compost amendment. Twenty promising PGPB isolates were used as seed inoculants in a series of greenhouse studies to examine revegetation of an extremely acidic, high metal content tailings samplemore » previously shown to require 15% compost amendment for normal plant growth. Several isolates significantly enhanced growth of two native species, quailbush and buffalo grass, in tailings. In this study, PGPB/compost outcomes were plant specific; for quailbush, PGPB were most effective in combination with 10% compost addition while for buffalo grass, PGPB enhanced growth in the complete absence of compost. Results indicate that selected PGPB can improve plant establishment and reduce the need for compost amendment. Further, PGPB activities necessary for aiding plant growth in mine tailings likely include tolerance to acidic pH and metals.« less

Interactions with Astroglia Influence the Shape of the Developing Dendritic Arbor and Restrict Dendrite Growth Independent of Promoting Synaptic Contacts

PubMed Central

Farley, Jennifer R.; Sterritt, Jeffrey R.; Crane, Andrés B.; Wallace, Christopher S.

2017-01-01

Astroglia play key roles in the development of neurons, ranging from regulating neuron survival to promoting synapse formation, yet basic questions remain about whether astrocytes might be involved in forming the dendritic arbor. Here, we used cultured hippocampal neurons as a simple in vitro model that allowed dendritic growth and geometry to be analyzed quantitatively under conditions where the extent of interactions between neurons and astrocytes varied. When astroglia were proximal to neurons, dendrites and dendritic filopodia oriented toward them, but the general presence of astroglia significantly reduced overall dendrite growth. Further, dendritic arbors in partial physical contact with astroglia developed a pronounced pattern of asymmetrical growth, because the dendrites in direct contact were significantly smaller than the portion of the arbor not in contact. Notably, thrombospondin, the astroglial factor shown previously to promote synapse formation, did not inhibit dendritic growth. Thus, while astroglia promoted the formation of presynaptic contacts onto dendrites, dendritic growth was constrained locally within a developing arbor at sites where dendrites contacted astroglia. Taken together, these observations reveal influences on spatial orientation of growth as well as influences on morphogenesis of the dendritic arbor that have not been previously identified. PMID:28081563

Evaluation of the advanced operating system of the Ann Arbor Transit Authority

DOT National Transportation Integrated Search

1999-10-01

These reports constitute an evaluation of the intelligent transportation system deployment efforts of the Ann Arbor Transportation Authority. These efforts, collectively termed "Advanced Operating System" (AOS), represent a vision of an integrated ad...

Plant growth-promoting bacteria for phytostabilization of mine tailings.

PubMed

Grandlic, Christopher J; Mendez, Monica O; Chorover, Jon; Machado, Blenda; Maier, Raina M

2008-03-15

Eolian dispersion of mine tailings in arid and semiarid environments is an emerging global issue for which economical remediation alternatives are needed. Phytostabilization, the revegetation of these sites with native plants, is one such alternative. Revegetation often requires the addition of bulky amendments such as compost which greatly increases cost. We report the use of plant growth-promoting bacteria (PGPB) to enhance the revegetation of mine tailings and minimize the need for compost amendment. Twenty promising PGPB isolates were used as seed inoculants in a series of greenhouse studies to examine revegetation of an extremely acidic, high metal contenttailings sample previously shown to require 15% compost amendment for normal plant growth. Several isolates significantly enhanced growth of two native species, quailbush and buffalo grass, in tailings. In this study, PGPB/compost outcomes were plant specific; for quailbush, PGPB were most effective in combination with 10% compost addition while for buffalo grass, PGPB enhanced growth in the complete absence of compost. Results indicate that selected PGPB can improve plant establishment and reduce the need for compost amendment. Further, PGPB activities necessary for aiding plant growth in mine tailings likely include tolerance to acidic pH and metals.

Microglia show altered morphology and reduced arborization in human brain during aging and Alzheimer's disease.

PubMed

Davies, Danielle S; Ma, Jolande; Jegathees, Thuvarahan; Goldsbury, Claire

2017-11-01

Changes in microglia function are involved in Alzheimer's disease (AD) for which ageing is the major risk factor. We evaluated microglial cell process morphologies and their gray matter coverage (arborized area) during ageing and in the presence and absence of AD pathology in autopsied human neocortex. Microglial cell processes were reduced in length, showed less branching and reduced arborized area with aging (case range 52-98 years). This occurred during normal ageing and without microglia dystrophy or changes in cell density. There was a larger reduction in process length and arborized area in AD compared to aged-matched control microglia. In AD cases, on average, 49%-64% of microglia had discontinuous and/or punctate Iba1 labeled processes instead of continuous Iba1 distribution. Up to 16% of aged-matched control microglia displayed discontinuous or punctate features. There was no change in the density of microglial cell bodies in gray matter during ageing or AD. This demonstrates that human microglia show progressive cell process retraction without cell loss during ageing. Additional changes in microglia occur with AD including Iba1 protein puncta and discontinuity. We suggest that reduced microglial arborized area may be an aging-related correlate of AD in humans. These variations in microglial cells during ageing and in AD could reflect changes in neural-glial interactions which are emerging as key to mechanisms involved in ageing and neurodegenerative disease. © 2016 International Society of Neuropathology.

Assessing Arboreal Adaptations of Bird Antecedents: Testing the Ecological Setting of the Origin of the Avian Flight Stroke

PubMed Central

Dececchi, T. Alexander; Larsson, Hans C. E.

2011-01-01

The origin of avian flight is a classic macroevolutionary transition with research spanning over a century. Two competing models explaining this locomotory transition have been discussed for decades: ground up versus trees down. Although it is impossible to directly test either of these theories, it is possible to test one of the requirements for the trees-down model, that of an arboreal paravian. We test for arboreality in non-avian theropods and early birds with comparisons to extant avian, mammalian, and reptilian scansors and climbers using a comprehensive set of morphological characters. Non-avian theropods, including the small, feathered deinonychosaurs, and Archaeopteryx, consistently and significantly cluster with fully terrestrial extant mammals and ground-based birds, such as ratites. Basal birds, more advanced than Archaeopteryx, cluster with extant perching ground-foraging birds. Evolutionary trends immediately prior to the origin of birds indicate skeletal adaptations opposite that expected for arboreal climbers. Results reject an arboreal capacity for the avian stem lineage, thus lending no support for the trees-down model. Support for a fully terrestrial ecology and origin of the avian flight stroke has broad implications for the origin of powered flight for this clade. A terrestrial origin for the avian flight stroke challenges the need for an intermediate gliding phase, presents the best resolved series of the evolution of vertebrate powered flight, and may differ fundamentally from the origin of bat and pterosaur flight, whose antecedents have been postulated to have been arboreal and gliding. PMID:21857918

Assessing arboreal adaptations of bird antecedents: testing the ecological setting of the origin of the avian flight stroke.

PubMed

Dececchi, T Alexander; Larsson, Hans C E

2011-01-01

The origin of avian flight is a classic macroevolutionary transition with research spanning over a century. Two competing models explaining this locomotory transition have been discussed for decades: ground up versus trees down. Although it is impossible to directly test either of these theories, it is possible to test one of the requirements for the trees-down model, that of an arboreal paravian. We test for arboreality in non-avian theropods and early birds with comparisons to extant avian, mammalian, and reptilian scansors and climbers using a comprehensive set of morphological characters. Non-avian theropods, including the small, feathered deinonychosaurs, and Archaeopteryx, consistently and significantly cluster with fully terrestrial extant mammals and ground-based birds, such as ratites. Basal birds, more advanced than Archaeopteryx, cluster with extant perching ground-foraging birds. Evolutionary trends immediately prior to the origin of birds indicate skeletal adaptations opposite that expected for arboreal climbers. Results reject an arboreal capacity for the avian stem lineage, thus lending no support for the trees-down model. Support for a fully terrestrial ecology and origin of the avian flight stroke has broad implications for the origin of powered flight for this clade. A terrestrial origin for the avian flight stroke challenges the need for an intermediate gliding phase, presents the best resolved series of the evolution of vertebrate powered flight, and may differ fundamentally from the origin of bat and pterosaur flight, whose antecedents have been postulated to have been arboreal and gliding.

Designing a fixed-blade gang ripsaw arbor with a pencil

Treesearch

Charles J. Gatchell; Charles J. Gatchell

1996-01-01

This paper presents a step-by-step procedure for designing the "best" sequence of saw spacings for a fixed-blade gang ripsaw arbor. Using the information contained in a cutting bill and knowledge of the lumber width distributions to be processed, thousands of possible saw spacing sequences can be reduced to a few good ones.

Braking system for use with an arbor of a microscope

DOEpatents

Norgren, Duane U.

1984-01-01

A balanced braking system comprising a plurality of braking assemblies located about a member to be braked. Each of the braking assemblies consists of a spring biased piston of a first material fitted into a body of a different material which has a greater contraction upon cooling than the piston material. The piston is provided with a recessed head portion over which is positioned a diaphragm and forming a space therebetween to which is connected a pressurized fluid supply. The diaphragm is controlled by the fluid in the space to contact or withdraw from the member to be braked. A cooling device causes the body within which the piston is fitted to contract more than the piston, producing a tight shrink fit therebetween. The braking system is particularly applicable for selectively braking an arbor of an electron microscope which immobilizes, for example, a vertically adjustable low temperature specimen holder during observation. The system provides balanced braking forces which can be easily removed and re-established with minimal disturbance to arbor location.

Factors influencing habitat selection by arboreal pit vipers.

PubMed

Sawant, Nitin S; Jadhav, Trupti D

2013-01-01

We studied factors influencing habitat selection by two arboreal species of pit viper, namely Trimeresurus malabaricus (Malabar pit viper) and T. gramineus (Bamboo pit viper). The macrohabitat of these species was classified as forest, forest edge, or open habitat. To determine microhabitat selection, a variety of features at every other snake location were measured. Whether or not the animal was found in a tree, the tree species, its height of perch, position on the branch (distal/ apical/middle), diameter of the branch, the tree canopy (thick/sparse) and vegetation of the area (thick/sparse) were recorded. Assessment of habitat was done to determine how patterns of habitat use vary seasonally. Shaded ambient (air) temperatures and humidity were recorded. Data pertaining to 90 individuals of T. malabaricus and 100 individuals of T. gramineus were recorded. Trimeresurus malabaricus selected home ranges that included areas with thick vegetation and were encountered at regions of higher altitude. Neither of the species was found in open habitats. Both of the species preferred diverse habitats and were spread over the entire available space during the monsoon; they did not show any preference for the perch height during different seasons. Males had a positive correlation between body mass and preferred perch diameter. The present study suggests that several factors play an important role in habitat selection by these arboreal pit vipers, thus making them highly habitat-specific.

Nutrient-dependent increased dendritic arborization of somatosensory neurons.

PubMed

Watanabe, Kaori; Furumizo, Yuki; Usui, Tadao; Hattori, Yukako; Uemura, Tadashi

2017-01-01

Suboptimal nutrition imposes developmental constraints on infant animals, which marshal adaptive responses to eventually become mature adults. Such responses are mounted at multiple levels from systemic to cellular. At the cellular level, the underlying mechanisms of cell proliferation control have been intensively studied. However, less is known about how growth of postmitotic and morphologically complex cells, such as neurons, is controlled by nutritional status. We address this question using Class I and Class IV dendritic arborization neurons in Drosophila larvae. Class IV neurons have been shown to sense nociceptive thermal, mechanical and light stimuli, whereas Class I neurons are proprioceptors. We reared larvae on diets with different protein and carbohydrate content throughout larval stages and examined how morphologies of Class I or Class IV neurons were affected. Dendritic arbors of Class IV neurons became more complex when larvae were reared on a low-yeast diet, which contains lower amounts of amino acids and other ingredients, compared to a high-yeast diet. In contrast, such low-yeast-dependent hyperarborization was not seen in Class I neurons. The physiological and metabolic implications of the hyperarborization phenotype are discussed in relation to a recent hypothesis that Class IV neurons sense protein-deficient stress and to our characterization of how the dietary yeast contents impacted larval metabolism. © 2016 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

THE NARROW X-RAY TAIL AND DOUBLE Hα TAILS OF ESO 137-002 IN A3627

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, B.; Lin, X. B.; Kong, X.

2013-11-10

We present the analysis of a deep Chandra observation of a ∼2 L{sub *} late-type galaxy, ESO 137-002, in the closest rich cluster A3627. The Chandra data reveal a long (∼>40 kpc) and narrow tail with a nearly constant width (∼3 kpc) to the southeast of the galaxy, and a leading edge ∼1.5 kpc from the galaxy center on the upstream side of the tail. The tail is most likely caused by the nearly edge-on stripping of ESO 137-002's interstellar medium (ISM) by ram pressure, compared to the nearly face-on stripping of ESO 137-001 discussed in our previous work. Spectralmore » analysis of individual regions along the tail shows that the gas throughout it has a rather constant temperature, ∼1 keV, very close to the temperature of the tails of ESO 137-001, if the same atomic database is used. The derived gas abundance is low (∼0.2 solar with the single-kT model), an indication of the multiphase nature of the gas in the tail. The mass of the X-ray tail is only a small fraction (<5%) of the initial ISM mass of the galaxy, suggesting that the stripping is most likely at an early stage. However, with any of the single-kT, double-kT, and multi-kT models we tried, the tail is always 'over-pressured' relative to the surrounding intracluster medium (ICM), which could be due to the uncertainties in the abundance, thermal versus non-thermal X-ray emission, or magnetic support in the ICM. The Hα data from the Southern Observatory for Astrophysical Research show a ∼21 kpc tail spatially coincident with the X-ray tail, as well as a secondary tail (∼12 kpc long) to the east of the main tail diverging at an angle of ∼23° and starting at a distance of ∼7.5 kpc from the nucleus. At the position of the secondary Hα tail, the X-ray emission is also enhanced at the ∼2σ level. We compare the tails of ESO 137-001 and ESO 137-002, and also compare the tails to simulations. Both the similarities and differences of the tails pose challenges to the simulations. Several

Subdigital setae of chameleon feet: friction-enhancing microstructures for a wide range of substrate roughness.

PubMed

Spinner, Marlene; Westhoff, Guido; Gorb, Stanislav N

2014-06-27

Hairy adhesive systems of microscopic setae with triangular flattened tips have evolved convergently in spiders, insects and arboreal lizards. The ventral sides of the feet and tails in chameleons are also covered with setae. However, chameleon setae feature strongly elongated narrow spatulae or fibrous tips. The friction enhancing function of these microstructures has so far only been demonstrated in contact with glass spheres. In the present study, the frictional properties of subdigital setae of Chamaeleo calyptratus were measured under normal forces in the physical range on plane substrates having different roughness. We showed that chameleon setae maximize friction on a wide range of substrate roughness. The highest friction was measured on asperities of 1 μm. However, our observations of the climbing ability of Ch. calyptratus on rods of different diameters revealed that also claws and grasping feet are additionally responsible for the force generation on various substrates during locomotion.

Subdigital setae of chameleon feet: Friction-enhancing microstructures for a wide range of substrate roughness

NASA Astrophysics Data System (ADS)

Spinner, Marlene; Westhoff, Guido; Gorb, Stanislav N.

2014-06-01

Hairy adhesive systems of microscopic setae with triangular flattened tips have evolved convergently in spiders, insects and arboreal lizards. The ventral sides of the feet and tails in chameleons are also covered with setae. However, chameleon setae feature strongly elongated narrow spatulae or fibrous tips. The friction enhancing function of these microstructures has so far only been demonstrated in contact with glass spheres. In the present study, the frictional properties of subdigital setae of Chamaeleo calyptratus were measured under normal forces in the physical range on plane substrates having different roughness. We showed that chameleon setae maximize friction on a wide range of substrate roughness. The highest friction was measured on asperities of 1 μm. However, our observations of the climbing ability of Ch. calyptratus on rods of different diameters revealed that also claws and grasping feet are additionally responsible for the force generation on various substrates during locomotion.

Changes in species diversity of arboreal spiders in Mexican coffee agroecosystems: untangling the web of local and landscape influences driving diversity

PubMed Central

Gonthier, David J.; Marín, Linda; Iverson, Aaron L.; Perfecto, Ivette

2014-01-01

Agricultural intensification is implicated as a major driver of global biodiversity loss. Local management and landscape scale factors both influence biodiversity in agricultural systems, but there are relatively few studies to date looking at how local and landscape scales influence biodiversity in tropical agroecosystems. Understanding what drives the diversity of groups of organisms such as spiders is important from a pragmatic point of view because of the important biocontrol services they offer to agriculture. Spiders in coffee are somewhat enigmatic because of their positive or lack of response to agricultural intensification. In this study, we provide the first analysis, to our knowledge, of the arboreal spiders in the shade trees of coffee plantations. In the Soconusco region of Chiapas, Mexico we sampled across 38 sites on 9 coffee plantations. Tree and canopy connectedness were found to positively influence overall arboreal spider richness and abundance. We found that different functional groups of spiders are responding to different local and landscape factors, but overall elevation was most important variable influencing arboreal spider diversity. Our study has practical management applications that suggest having shade grown coffee offers more suitable habitat for arboreal spiders due to a variety of the characteristics of the shade trees. Our results which show consistently more diverse arboreal spider communities in lower elevations are important in light of looming global climate change. As the range of suitable elevations for coffee cultivation shrinks promoting arboreal spider diversity will be important in sustaining the viability of coffee. PMID:25392751

Adolescent cocaine exposure simplifies orbitofrontal cortical dendritic arbors

PubMed Central

DePoy, Lauren M.; Perszyk, Riley E.; Zimmermann, Kelsey S.; Koleske, Anthony J.; Gourley, Shannon L.

2014-01-01

Cocaine and amphetamine remodel dendritic spines within discrete cortico-limbic brain structures including the orbitofrontal cortex (oPFC). Whether dendrite structure is similarly affected, and whether pre-existing cellular characteristics influence behavioral vulnerabilities to drugs of abuse, remain unclear. Animal models provide an ideal venue to address these issues because neurobehavioral phenotypes can be defined both before, and following, drug exposure. We exposed mice to cocaine from postnatal days 31–35, corresponding to early adolescence, using a dosing protocol that causes impairments in an instrumental reversal task in adulthood. We then imaged and reconstructed excitatory neurons in deep-layer oPFC. Prior cocaine exposure shortened and simplified arbors, particularly in the basal region. Next, we imaged and reconstructed orbital neurons in a developmental-genetic model of cocaine vulnerability—the p190rhogap+/– mouse. p190RhoGAP is an actin cytoskeleton regulatory protein that stabilizes dendrites and dendritic spines, and p190rhogap+/– mice develop rapid and robust locomotor activation in response to cocaine. Despite this, oPFC dendritic arbors were intact in drug-naïve p190rhogap+/– mice. Together, these findings provide evidence that adolescent cocaine exposure has long-term effects on dendrite structure in the oPFC, and they suggest that cocaine-induced modifications in dendrite structure may contribute to the behavioral effects of cocaine more so than pre-existing structural abnormalities in this cell population. PMID:25452728

Hippocampal neuronal subtypes develop abnormal dendritic arbors in the presence of Fragile X astrocytes.

PubMed

Jacobs, S; Cheng, C; Doering, L C

2016-06-02

Astrocytes are now recognized as key players in the neurobiology of neurodevelopmental disorders such as Fragile X syndrome. However, the nature of Fragile X astrocyte-mediated control of dendrite development in subtypes of hippocampal neurons is not yet known. We used a co-culture procedure in which wildtype primary hippocampal neurons were cultured with astrocytes from either a wildtype or Fragile X mouse, for either 7, 14 or 21 days. The neurons were processed for immunocytochemistry with the dendritic marker MAP2, classified by morphological criteria into one of five neuronal subtypes, and subjected to Sholl analyses. Both linear and semi-log methods of Sholl analyses were applied to the neurons in order to provide an in depth analysis of the dendritic arborizations. We found that Fragile X astrocytes affect the development of dendritic arborization of all subtypes of wildtype hippocampal neurons. Furthermore, we show that hippocampal neurons with spiny stellate neuron morphology exhibit the most pervasive developmental delays, with significant dendritic arbor alterations persisting at 21 days in culture. The results further dictate the critical role astrocytes play in governing neuronal morphology including altered dendrite development in Fragile X. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

78 FR 65380 - Notice of Inventory Completion: University of Michigan, Ann Arbor, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-31

... the University of Michigan, Ann Arbor, MI. The human remains were removed from Alpena, Isabella, Grand... removed from the Devil River Mound site (20AL1) in Alpena County, MI. A resident of Ossineke, MI...

Subdigital setae of chameleon feet: Friction-enhancing microstructures for a wide range of substrate roughness

PubMed Central

Spinner, Marlene; Westhoff, Guido; Gorb, Stanislav N.

2014-01-01

Hairy adhesive systems of microscopic setae with triangular flattened tips have evolved convergently in spiders, insects and arboreal lizards. The ventral sides of the feet and tails in chameleons are also covered with setae. However, chameleon setae feature strongly elongated narrow spatulae or fibrous tips. The friction enhancing function of these microstructures has so far only been demonstrated in contact with glass spheres. In the present study, the frictional properties of subdigital setae of Chamaeleo calyptratus were measured under normal forces in the physical range on plane substrates having different roughness. We showed that chameleon setae maximize friction on a wide range of substrate roughness. The highest friction was measured on asperities of 1 μm. However, our observations of the climbing ability of Ch. calyptratus on rods of different diameters revealed that also claws and grasping feet are additionally responsible for the force generation on various substrates during locomotion. PMID:24970387

Prey Capture Behavior in an Arboreal African Ponerine Ant

PubMed Central

Dejean, Alain

2011-01-01

I studied the predatory behavior of Platythyrea conradti, an arboreal ponerine ant, whereas most species in this subfamily are ground-dwelling. The workers, which hunt solitarily only around dusk, are able to capture a wide range of prey, including termites and agile, nocturnal insects as well as diurnal insects that are inactive at that moment of the Nyctemeron, resting on tree branches or under leaves. Prey are captured very rapidly, and the antennal palpation used by ground-dwelling ponerine species is reduced to a simple contact; stinging occurs immediately thereafter. The venom has an instant, violent effect as even large prey (up to 30 times the weight of a worker) never struggled after being stung. Only small prey are not stung. Workers retrieve their prey, even large items, singly. To capture termite workers and soldiers defending their nest entrances, ant workers crouch and fold their antennae backward. In their role as guards, the termites face the crouching ants and end up by rolling onto their backs, their legs batting the air. This is likely due to volatile secretions produced by the ants' mandibular gland. The same behavior is used against competing ants, including territorially-dominant arboreal species that retreat further and further away, so that the P. conradti finally drive them from large, sugary food sources. PMID:21589941

Arboreal behavior in the timber rattlesnake, Crotalus horridus, in eastern Texas

Treesearch

D. Craig Rudolph; R. R. Schaefer; D. Saenz; R. N. Conner

2004-01-01

There have been several recent reports, and anecdotal observations extending back at least to J. J. Audubon, suggesting that the timber rattlesnake (Crotalus horridus) is one of the most arboreal members of the genus. Most previous records are of snakes located at heights of less than 5 m. Telemetry studies in eastern Texas have documented more...

Visualization of Motor Axon Navigation and Quantification of Axon Arborization In Mouse Embryos Using Light Sheet Fluorescence Microscopy.

PubMed

Liau, Ee Shan; Yen, Ya-Ping; Chen, Jun-An

2018-05-11

Spinal motor neurons (MNs) extend their axons to communicate with their innervating targets, thereby controlling movement and complex tasks in vertebrates. Thus, it is critical to uncover the molecular mechanisms of how motor axons navigate to, arborize, and innervate their peripheral muscle targets during development and degeneration. Although transgenic Hb9::GFP mouse lines have long served to visualize motor axon trajectories during embryonic development, detailed descriptions of the full spectrum of axon terminal arborization remain incomplete due to the pattern complexity and limitations of current optical microscopy. Here, we describe an improved protocol that combines light sheet fluorescence microscopy (LSFM) and robust image analysis to qualitatively and quantitatively visualize developing motor axons. This system can be easily adopted to cross genetic mutants or MN disease models with Hb9::GFP lines, revealing novel molecular mechanisms that lead to defects in motor axon navigation and arborization.

Vane emargination of outer tail feathers improves flight manoeuvrability in streamerless hirundines, Hirundinidae.

PubMed Central

Matyjasiak, Piotr; Matyjasiak, Jolanta; de Lope, Florentino; Møller, Anders P.

2004-01-01

Recent studies have suggested that the proximal part of the swallow (Hirundo rustica) tail streamer appears to aid turning flight, as expected if streamers evolved initially purely through natural selection for enhanced manoeuvrability. However, the evolution of slender aerodynamically advantageous streamers is also predicted by an alternative hypothesis, which suggests that such a trait could develop primarily to ameliorate the aerodynamic cost of a long size-dimorphic tail. To distinguish between these hypotheses, we have investigated for the effect on manoeuvrability of trimming the tips of the outer tail feathers into short streamers, without lengthening these feathers, in two streamerless hirundine species--the house martin (Delichon urbica) and the sand martin (Riparia riparia). This allowed us to examine the aerodynamic costs and benefits of streamers at an early evolutionary stage that predates elongation of the outermost tail feathers through female choice. We showed that such initial streamers enhance manoeuvrability in streamerless hirundines, confirming the findings of recent studies. However, in contrast to these studies, we showed that improved manoeuvrability resulting from streamers could arise before the outermost tail feathers have become elongated (e.g. owing to female choice). The occurrence of such an aerodynamic advantage depends on the ancestral shape of a forked tail. This provides support for the hypothesis that streamers, like those in the barn swallow, might evolve initially purely through natural selection for enhanced manoeuvrability. PMID:15315899

Band tailing and efficiency limitation in kesterite solar cells

NASA Astrophysics Data System (ADS)

Gokmen, Tayfun; Gunawan, Oki; Todorov, Teodor K.; Mitzi, David B.

2013-09-01

We demonstrate that a fundamental performance bottleneck for hydrazine processed kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells with efficiencies reaching above 11% can be the formation of band-edge tail states, which quantum efficiency and photoluminescence data indicate is roughly twice as severe as in higher-performing Cu(In,Ga)(S,Se)2 devices. Low temperature time-resolved photoluminescence data suggest that the enhanced tailing arises primarily from electrostatic potential fluctuations induced by strong compensation and facilitated by a lower CZTSSe dielectric constant. We discuss the implications of the band tails for the voltage deficit in these devices.

MESSENGER Observations of Extreme Loading and Unloading of Mercury's Magnetic Tail

NASA Technical Reports Server (NTRS)

Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Gloeckler, George; Gold, Robert E.; Ho, George C.; Korth, Haje; Krimigis, Stamatios M.;

Slow but tenacious: an analysis of running and gripping performance in chameleons.

PubMed

Herrel, Anthony; Tolley, Krystal A; Measey, G John; da Silva, Jessica M; Potgieter, Daniel F; Boller, Elodie; Boistel, Renaud; Vanhooydonck, Bieke

2013-03-15

Chameleons are highly specialized and mostly arboreal lizards characterized by a suite of derived characters. The grasping feet and tail are thought to be related to the arboreal lifestyle of chameleons, yet specializations for grasping are thought to exhibit a trade-off with running ability. Indeed, previous studies have demonstrated a trade-off between running and clinging performance, with faster species being poorer clingers. Here we investigate the presence of trade-offs by measuring running and grasping performance in four species of chameleon belonging to two different clades (Chamaeleo and Bradypodion). Within each clade we selected a largely terrestrial species and a more arboreal species to test whether morphology and performance are related to habitat use. Our results show that habitat drives the evolution of morphology and performance but that some of these effects are specific to each clade. Terrestrial species in both clades show poorer grasping performance than more arboreal species and have smaller hands. Moreover, hand size best predicts gripping performance, suggesting that habitat use drives the evolution of hand morphology through its effects on performance. Arboreal species also had longer tails and better tail gripping performance. No differences in sprint speed were observed between the two Chamaeleo species. Within Bradypodion, differences in sprint speed were significant after correcting for body size, yet the arboreal species were both better sprinters and had greater clinging strength. These results suggest that previously documented trade-offs may have been caused by differences between clades (i.e. a phylogenetic effect) rather than by design conflicts between running and gripping per se.

Natural canopy bridges effectively mitigate tropical forest fragmentation for arboreal mammals.

PubMed

Gregory, Tremaine; Carrasco-Rueda, Farah; Alonso, Alfonso; Kolowski, Joseph; Deichmann, Jessica L

2017-06-20

Linear infrastructure development and resulting habitat fragmentation are expanding in Neotropical forests, and arboreal mammals may be disproportionately impacted by these linear habitat clearings. Maintaining canopy connectivity through preservation of connecting branches (i.e. natural canopy bridges) may help mitigate that impact. Using camera traps, we evaluated crossing rates of a pipeline right-of-way in a control area with no bridges and in a test area where 13 bridges were left by the pipeline construction company. Monitoring all canopy crossing points for a year (7,102 canopy camera nights), we confirmed bridge use by 25 mammal species from 12 families. With bridge use beginning immediately after exposure and increasing over time, use rates were over two orders of magnitude higher than on the ground. We also found a positive relationship between a bridge's use rate and the number of species that used it, suggesting well-used bridges benefit multiple species. Data suggest bridge use may be related to a combination of bridge branch connectivity, multiple connections, connectivity to adjacent forest, and foliage cover. Given the high use rate and minimal cost, we recommend all linear infrastructure projects in forests with arboreal mammal populations include canopy bridges.

The legacy of logging--estimating arboreal lichen occurrence in a boreal multiple-use landscape on a two century scale.

PubMed

Horstkotte, Tim; Moen, Jon; Lämås, Tomas; Helle, Timo

2011-01-01

In northern Sweden, the availability of arboreal lichens (Bryoria fuscescens, Alectoria sarmentosa) as winter grazing resources is an important element in reindeer husbandry. With the industrialization of forestry, forests rich in arboreal lichens have diminished considerably. Here, we analyze how forestry has impacted lichen availability from the 1920's to the present day and model its future development assuming different forest management scenarios.We recorded the current occurrence of B. fuscescens in 144 sampling plots, stratified by forest age class and dominant tree species in a 26,600 ha boreal forest landscape that is used for both reindeer herding and forestry. Lichen abundance was visually estimated in four classes: none, sparse, moderate and abundant. A binary logistic model using forest age as the independent variable was developed to predict the probability of lichens being present. Using this model, we found that lichens were present in stands that are at least 63 years old. Because of the relative paucity of stands rich in arboreal lichens, it was not possible to reliably determine how age affects the variation in abundance of older forest stands. The historical development of forests where arboreal lichens could potentially occur was studied using historic forestry records dating back 80 years. Between 1926 and the present day, forestry has reduced the cover of forests older than 60 years from 84% to 34%. The likely future spatial coverage of these stands over the next 120 years was estimated for two different management scenarios and an unmanaged reference scenario, using the Heureka strategic planning program. Under both the "business as usual" scenario and that involving more intensive forestry, continued decreases in lichen availability are projected. Our results emphasize the importance of alternative forestry practices, such as prolonged rotation periods, to increase the availability of arboreal lichens as a grazing resource for reindeer.

Transformation of synaptic vesicle phenotype in the intramedullary axonal arbors of cat spinal motoneurons following peripheral nerve injury.

PubMed

Havton, L A; Kellerth, J O

2001-08-01

Permanent transection of a peripheral motor nerve induces a gradual elimination of whole axon collateral systems in the axotomized spinal motoneurons. There is also an initial concurrent decrease in the amount of recurrent inhibition exerted by these arbors in the spinal cord for up to 6 weeks after the injury, whereas the same reflex action returns to normal by the 12-week postoperative state. The aim of the present investigation was to study the fine structure of the intramedullary axonal arbors of axotomized alpha-motoneurons in the adult cat spinal cord following a permanent peripheral motor nerve lesion. For this purpose, single axotomized alpha-motoneurons were labeled intracellularly with horseradish peroxidase at 12 weeks after permanent transection of their peripheral motor nerve. The intramedullary portions of their motor axon and axon collateral arbors were first reconstructed at the light microscopic level and subsequently studied ultrastructurally. This study shows that the synaptic contacts made by the intramedullary axon collateral arbors of axotomized motoneurons have undergone a change in synaptic vesicle ultrastructure from spherical and clear vesicles to spherical and dense-cored vesicles at 12 weeks after the transection of their peripheral axons. We suggest that the present transformation in synaptic vesicle fine structure may also correspond to a change in the contents of these boutons. This may, in turn, be responsible for the strengthening and recovery of the recurrent inhibitory reflex action exerted by the axotomized spinal motoneurons following a prolonged permanent motor nerve injury.

Dynamics of terminal arbor formation and target approach of retinotectal axons in living zebrafish embryos: a time-lapse study of single axons.

PubMed

Kaethner, R J; Stuermer, C A

1992-08-01

In a variety of species, developing retinal axons branch initially more widely in their visual target centers and only gradually restrict their terminal arbors to smaller and defined territories. Retinotectal axons in fish, however, appeared to grow in a directed manner and to arborize only at their retinotopic target sites. To visualize the dynamics of retinal axon growth and arbor formation in fish, time-lapse recordings were made of individual retinal ganglion cell axons in the tectum in live zebrafish embryos. Axons were labeled with the fluorescent carbocyanine dyes Dil or DiO inserted as crystals into defined regions of the retina, viewed with 40x and 100x objectives with an SIT camera, and recorded, with exposure times of 200 msec at 30 or 60 sec intervals, over time periods of up to 13 hr. (1) Growth cones advanced rapidly, but the advance was punctuated by periods of rest. During the rest periods, the growth cones broadened and developed filopodia, but during extension they were more streamlined. (2) Growth cones traveled unerringly into the direction of their retinotopic targets without branching en route. At their target and only there, the axons began to form terminal arborizations, a process that involved the emission and retraction of numerous short side branches. The area that was permanently occupied or touched by transient branches of the terminal arbor--"the exploration field"--was small and almost circular and covered not more than 5.3% of the entire tectal surface area, but represented up to six times the size of the arbor at any one time. These findings are consistent with the idea that retinal axons are guided to their retinotopic target sites by sets of positional markers, with a graded distribution over the axes of the tectum.

Near-tail reconnection as the cause of cometary tail disconnections

NASA Technical Reports Server (NTRS)

Russell, C. T.; Saunders, M. A.; Phillips, J. L.; Fedder, J. A.

1986-01-01

In a cometary tail disconnection event the plasma tail appears to separate from the coma and to accelerate away from it. As this occurs a new tail begins to form. It is proposed that these disconnections arise in a manner analogous to geomagnetic substorms, i.e., by the formation of a strongly reconnecting region in the near tail that forms a magnetic island in the coma and ejects the plasma tail by strengthening the magnetic 'slingshot' within the tail. This reconnection process may be triggered by several different processes, such as interplanetary shocks or variations in the Alfven Mach number.

Performance Enhancement of a Vertical Tail Model with Sweeping Jet Actuators

NASA Technical Reports Server (NTRS)

Seele, Roman; Graff, Emilio; Lin, John; Wygnanski, Israel

2013-01-01

Active Flow Control (AFC) experiments performed at the Caltech Lucas Adaptive Wall Wind Tunnel on a 12%-thick, generic vertical tail model indicated that sweeping jets emanating from the trailing edge (TE) of the vertical stabilizer significantly increased the side force coefficient for a wide range of rudder deflection angles and yaw angles at free-stream velocities approaching takeoff rotation speed. The results indicated that 2% blowing momentum coefficient (C(sub mu) increased the side force in excess of 50% at the maximum conventional rudder deflection angle in the absence of yaw. Even C(sub mu) = 0.5% increased the side force in excess of 20% under these conditions. This effort was sponsored by the NASA Environmentally Responsible Aviation (ERA) project and the successful demonstration of this flow-control application could have far reaching implications. It could lead to effective applications of AFC technologies on key aircraft control surfaces and lift enhancing devices (flaps) that would aid in reduction of fuel consumption through a decrease in size and weight of wings and control surfaces or a reduction of the noise footprint due to steeper climb and descent.

Evaluation Of The Advanced Operating System Of The Ann Arbor Transportation Authority : AATA Web Survey

DOT National Transportation Integrated Search

1999-01-01

During 1997, visitors to the Ann Arbor (Michigan) Transportation Authority's worldwide web site were invited to complete an electronic questionnaire about their experience with the site. Eighty surveys were collected, representing a non-scientific se...

Metallicity gradients in tidal tails and merging systems

NASA Astrophysics Data System (ADS)

Torres-Flores, S.; Scarano, S., Jr.; Olave, D.; Alfaro, M.; Mendes de Oliveira, C.; de Mello, D. F.; Carrasco, E. R.; Amram, P.; Plana, H.

2014-10-01

We present an analysis of the metal distribution in the tidal tails of two interacting systems and in the main body of a galaxy merger: NGC92, NGC6845 and HCG31, respectively. Using Gemini/GMOS spectroscopic data, we found no metallicity gradients for the tail of NGC92. The abundances in the tail are similar to the values displayed by the central regions of NGC92. This fact suggests that gas mixing triggered by the interaction produces a flattening in the metallicity distribution of this system. For the system NGC6845, we found that regions located in the tail have similar abundances to one source located in the inner region of this galaxy, also suggesting a flat metal distribution. For HCG 31 we found an inhomogeneous metal distribution for the central region. Apparently, each star forming complex keeps its metal abundance despite the strong gravitational interaction that this system suffered. In the case of the tidal tails, our results support the scenario in which gas mixing produces a flattening in the metal distribution. However, we suggest that the star formation is an important mechanism in enhancing the oxygen abundance of these structures.

Evaluation Of The Advanced Operating System Of The Ann Arbor Transportation Authority : Archives And Records

DOT National Transportation Integrated Search

1999-01-01

This study examines data regularly maintained by the AATA (Ann Arbor Transportation Authority) for evidence of AOS (Advanced Operating System) impact. These data include on-time performance, bus trips broken because of maintenance or other incidents,...

Mobilization of radionuclides from uranium mill tailings and related waste materials in anaerobic environments

USGS Publications Warehouse

Landa, E.R.

2003-01-01

Specific extraction studies in our laboratory have shown that iron and manganese oxide- and alkaline earth sulfate minerals are important hosts of radium in uranium mill tailings. Iron- and sulfate-reducing bacteria may enhance the release of radium (and its analog barium) from uranium mill tailings, oil field pipe scale [a major technologically enhanced naturally occurring radioactive material (TENORM) waste], and jarosite (a common mineral in sulfuric acid processed-tailings). These research findings are reviewed and discussed in the context of nuclear waste forms (such as barium sulfate matrices), radioactive waste management practices, and geochemical environments in the Earth's surficial and shallow subsurface regions.

CCL19 with CCL21-tail displays enhanced glycosaminoglycan binding with retained chemotactic potency in dendritic cells.

PubMed

Jørgensen, Astrid S; Adogamhe, Pontian E; Laufer, Julia M; Legler, Daniel F; Veldkamp, Christopher T; Rosenkilde, Mette M; Hjortø, Gertrud M

2018-05-16

CCL19 is more potent than CCL21 in inducing chemotaxis of human dendritic cells (DC). This difference is attributed to 1) a stronger interaction of the basic C-terminal tail of CCL21 with acidic glycosaminoglycans (GAGs) in the environment and 2) an autoinhibitory function of this C-terminal tail. Moreover, different receptor docking modes and tissue expression patterns of CCL19 and CCL21 contribute to fine-tuned control of CCR7 signaling. Here, we investigate the effect of the tail of CCL21 on chemokine binding to GAGs and on CCR7 activation. We show that transfer of CCL21-tail to CCL19 (CCL19 CCL21-tail ) markedly increases binding of CCL19 to human dendritic cell surfaces, without impairing CCL19-induced intracellular calcium release or DC chemotaxis, although it causes reduced CCR7 internalization. The more potent chemotaxis induced by CCL19 and CCL19 CCL21-tail compared to CCL21 is not transferred to CCL21 by replacing its N-terminus with that of CCL19 (CCL21 CCL19-N-term ). Measurements of cAMP production in CHO cells uncover that CCL21-tail transfer (CCL19 CCL21-tail ) negatively affects CCL19 potency, whereas removal of CCL21-tail (CCL21 tailless ) increases signaling compared to full-length CCL21, indicating that the tail negatively affects signaling via cAMP. Similar to chemokine-driven calcium mobilization and chemotaxis, the potency of CCL21 in cAMP is not improved by transfer of the CCL19 N-terminus to CCL21 (CCL21 CCL19-N-term ). Together these results indicate that ligands containing CCL21 core and C-terminal tail (CCL21 and CCL21 CCL19-N-term ) are most restricted in their cAMP signaling; a phenotype attributed to a stronger GAG binding of CCL21 and defined structural differences between CCL19 and CCL21. ©2018 Society for Leukocyte Biology.

Surface shape affects the three-dimensional exploratory movements of nocturnal arboreal snakes.

PubMed

Jayne, Bruce C; Olberding, Jeffrey P; Athreya, Dilip; Riley, Michael A

2012-12-01

Movement and searching behaviors at diverse spatial scales are important for understanding how animals interact with their environment. Although the shapes of branches and the voids in arboreal habitats seem likely to affect searching behaviors, their influence is poorly understood. To gain insights into how both environmental structure and the attributes of an animal may affect movement and searching, we compared the three-dimensional exploratory movements of snakes in the dark on two simulated arboreal surfaces (disc and horizontal cylinder). Most of the exploratory movements of snakes in the dark were a small fraction of the distances they could reach while bridging gaps in the light. The snakes extended farther away from the edge of the supporting surface at the ends of the cylinder than from the sides of the cylinder or from any direction from the surface of the disc. The exploratory movements were not random, and the surface shape and three-dimensional directions had significant interactive effects on how the movements were structured in time. Thus, the physical capacity for reaching did not limit the area that was explored, but the shape of the supporting surface and the orientation relative to gravity did create biased searching patterns.

Nocturnal arboreality in snakes in the swamplands of the Atchafalaya Basin of south-central Louisiana and Big Thicket National Preserve of Southeast Texas

USGS Publications Warehouse

Glorioso, Brad M.; Waddle, J. Hardin

2017-01-01

The southeastern United States is home to a diverse assemblage of snakes, but only one species, the Rough Greensnake (Opheodrys aestivus), is considered specialized for a predominantly arboreal lifestyle. Other species, such as Ratsnakes (genus Pantherophis) and Ribbonsnakes/Gartersnakes (genus Thamnophis), are widely known to climb into vegetation and trees. Some explanations given for snake climbing behavior are foraging, thermoregulation, predator avoidance, and response to flood. Reports of arboreality in snake species typically not associated with life in the trees (such as terrestrial, aquatic, and even fossorial species) usually come from single observations, with no knowledge of prevalence of the behavior. Here, we report on arboreality of snake species detected during 8 years of night surveys in the Atchafalaya Basin of south-central Louisiana and 5+ years of night surveys in Big Thicket National Preserve in southeast Texas. We recorded a total of 1,088 detections of 19 snake species between the two study areas, with 348 detections above ground level (32%). The Rough Greensnake and Western Ribbonsnake (Thamnophis proximus) accounted for nearly 75% of total arboreal detections among the two study areas. However, with one exception, all snake species detected more than once between both study areas had at least one arboreal detection. These observations demonstrate that snakes with widely varying natural histories may be found in the trees at night, and for some species, this behavior may be more common than previously believed.

Tail gut cyst.

PubMed

Rao, G Mallikarjuna; Haricharan, P; Ramanujacharyulu, S; Reddy, K Lakshmi

2002-01-01

The tail gut is a blind extension of the hindgut into the tail fold just distal to the cloacal membrane. Remnants of this structure may form tail gut cyst. We report a 14-year-old girl with tail gut cyst that presented as acute abdomen. The patient recovered after cyst excision.

Telling tails: selective pressures acting on investment in lizard tails.

PubMed

Fleming, Patricia A; Valentine, Leonie E; Bateman, Philip W

2013-01-01

Caudal autotomy is a common defense mechanism in lizards, where the animal may lose part or all of its tail to escape entrapment. Lizards show an immense variety in the degree of investment in a tail (i.e., length) across species, with tails of some species up to three or four times body length (snout-vent length [SVL]). Additionally, body size and form also vary dramatically, including variation in leg development and robustness and length of the body and tail. Autotomy is therefore likely to have fundamentally different effects on the overall body form and function in different species, which may be reflected directly in the incidence of lost/regenerating tails within populations or, over a longer period, in terms of relative tail length for different species. We recorded data (literature, museum specimens, field data) for relative tail length (n=350 species) and the incidence of lost/regenerating tails (n=246 species). We compared these (taking phylogeny into account) with intrinsic factors that have been proposed to influence selective pressures acting on caudal autotomy, including body form (robustness, body length, leg development, and tail specialization) and ecology (foraging behavior, physical and temporal niches), in an attempt to identify patterns that might reflect adaptive responses to these different factors. More gracile species have relatively longer tails (all 350 spp., P < 0.001; also significant for five of the six families tested separately), as do longer (all species, P < 0.001; Iguanidae, P < 0.05; Lacertidae, P < 0.001; Scindidae, P < 0.001), climbing (all species, P < 0.05), and diurnal (all species, P < 0.01; Pygopodidae, P < 0.01) species; geckos without specialized tails (P < 0.05); or active-foraging skinks (P < 0.05). We also found some relationships with the data for caudal autotomy, with more lost/regenerating tails for nocturnal lizards (all 246 spp., P < 0.01; Scindidae, P < 0.05), larger skinks (P < 0.05), climbing geckos (P < 0

Conservation and relative habitat suitability for an arboreal mammal associated with old forest

Treesearch

Mark A. Linnell; Raymond J. Davis; Damon B. Lesmeister; James K. Swingle

2017-01-01

Contraction of native old forest can limit occurrence of old forest associated species, especially species with limited vagility. Patterns of size and distribution of remaining patches of old forest along with forest disturbance and what replaces old forest can influence whether species adapt or perish after forest loss. The arboreal red tree vole (Arborimus...

Evolution and ecology of directed aerial descent in arboreal ants.

PubMed

Yanoviak, Stephen P; Munk, Yonatan; Dudley, Robert

2011-12-01

Directed aerial descent (DAD) is used by a variety of arboreal animals to escape predators, to remain in the canopy, and to access resources. Here, we build upon the discovery of DAD in ants of tropical canopies by summarizing its known phylogenetic distribution among ant genera, and within both the subfamily Pseudomyrmecinae and the genus Cephalotes. DAD has multiple evolutionary origins in ants, occurring independently in numerous genera in the subfamilies Myrmicinae, Formicinae, and Pseudomyrmecinae. Ablation experiments and video recordings of ants in a vertical wind tunnel showed that DAD in Cephalotes atratus is achieved via postural changes, specifically orientation of the legs and gaster. The occurrence of DAD in Formicinae indicates that the presence of a postpetiole is not essential for the behavior. Evidence to date indicates that gliding behavior is accomplished by visual targeting mediated by the compound eyes, and is restricted to diurnally active ants that nest in trees. Occlusion of ocelli in Pseudomyrmex gracilis workers had no effect on their success or performance in gliding. Experimental assessment of the fate of ants that fall to the understory showed that ants landing in water are 15 times more likely to suffer lethal attacks than are ants landing in leaf litter. Variation in both the aerodynamic mechanisms and selective advantages of DAD merits further study given the broad taxonomic diversity of arboreal ants that engage in this intriguing form of flight.

The generation of magnetic fields and electric currents in cometary plasma tails

NASA Technical Reports Server (NTRS)

Ip, W.-H.; Mendis, D. A.

1976-01-01

Due to the folding of the interplanetary magnetic field into the tail as a comet sweeps through the interplanetary medium, the magnetic field in the tail can be built up to the order of 100 gammas at a heliocentric distance of about 1 AU. This folding of magnetic flux tubes also results in a cross-tail electric current passing through a neutral sheet. When streams of enhanced plasma density merge with the main tail, cross-tail currents as large as 1 billion A may result. A condition could arise which causes a significant fraction of this current to be discharged through the inner coma, resulting in rapid ionization. The typical time scale for such outbursts of ionization is estimated to be of the order of 10,000 sec, which is in reasonable agreement with observation.

77 FR 7123 - ArborGen, LLC; Availability of an Environmental Assessment for Controlled Release of a...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-10

... Eucalyptus. ArborGen is requesting that trees be allowed to flower at four locations in Alabama, Florida and... have indicated they will not allow these trees to flower at these locations. Permit application 11-052...

Design of a MATLAB(registered trademark) Image Comparison and Analysis Tool for Augmentation of the Results of the Ann Arbor Distortion Test

DTIC Science & Technology

2016-06-25

The equipment used in this procedure includes: Ann Arbor distortion tester with 50-line grating reticule, IQeye 720 digital video camera with 12...and import them into MATLAB. In order to digitally capture images of the distortion in an optical sample, an IQeye 720 video camera with a 12... video camera and Ann Arbor distortion tester. Figure 8. Computer interface for capturing images seen by IQeye 720 camera. Once an image was

Foraging behavior of Long-tailed Ducks in a ferry wake

USGS Publications Warehouse

Perry, Matthew C.

2012-01-01

Clangula hyemalis (Long-tailed Ducks) were observed diving in the wake of the Nantucket Island ferry during December over a 5-year period (2005–2009). The unusual diving behavior appeared to be related to foraging, but could not be confirmed. Long-tailed Ducks typically feed on more mobile prey than most other diving ducks, and it is speculated that the propeller wash in shallow water dislodged or disturbed prey and provided an enhanced feeding opportunity. Long-tailed Ducks collected while feeding in a disturbed area near a clamming boat not far from the ferry channel were feeding predominantly on Crangon septemspinosa (Sand Shrimp) that apparently had been dislodged by the clamming operation.

MESSENGER Observations of Extreme Loading and Unloading of Mercury's Magnetic Tail

NASA Technical Reports Server (NTRS)

Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Gloeckler, George; Gold, Robert E.; Ho, George C.; Korth, Haje; Krimigis, Stamatios M.;

Enhanced t -3/2 long-time tail for the stress-stress time correlation function

NASA Astrophysics Data System (ADS)

Evans, Denis J.

1980-01-01

Nonequilibrium molecular dynamics is used to calculate the spectrum of shear viscosity for a Lennard-Jones fluid. The calculated zero-frequency shear viscosity agrees well with experimental argon results for the two state points considered. The low-frequency behavior of shear viscosity is dominated by an ω 1/2 cusp. Analysis of the form of this cusp reveals that the stress-stress time correlation function exhibits a t -3/2 "long-time tail." It is shown that for the state points studied, the amplitude of this long-time tail is between 12 and 150 times larger than what has been predicted theoretically. If the low-frequency results are truly asymptotic, they imply that the cross and potential contributions to the Kubo-Green integrand for shear viscosity exhibit a t -3/2 long-time tail. This result contradicts the established theory of such processes.

Muscarinic regulation of Kenyon cell dendritic arborizations in adult worker honey bees

PubMed Central

Dobrin, Scott E.; Herlihy, J. Daniel; Robinson, Gene E.; Fahrbach, Susan E.

2011-01-01

The experience of foraging under natural conditions increases the volume of mushroom body neuropil in worker honey bees. A comparable increase in neuropil volume results from treatment of worker honey bees with pilocarpine, an agonist for muscarinic-type cholinergic receptors. A component of the neuropil growth induced by foraging experience is growth of dendrites in the collar region of the calyces. We show here, via analysis of Golgi-impregnated collar Kenyon cells with wedge arborizations, that significant increases in standard measures of dendritic complexity were also found in worker honey bees treated with pilocarpine. This result suggests that signaling via muscarinic-type receptors promotes the increase in Kenyon cell dendritic complexity associated with foraging. Treatment of worker honey bees with scopolamine, a muscarinic inhibitor, inhibited some aspects of dendritic growth. Spine density on the Kenyon cell dendrites varied with sampling location, with the distal portion of the dendritic field having greater total spine density than either the proximal or medial section. This observation may be functionally significant because of the stratified organization of projections from visual centers to the dendritic arborizations of the collar Kenyon cells. Pilocarpine treatment had no effect on the distribution of spines on dendrites of the collar Kenyon cells. PMID:21262388

REAR PROFILE OF TAIL FROM SECOND LEVEL OF TAIL DOCK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

REAR PROFILE OF TAIL FROM SECOND LEVEL OF TAIL DOCK STAND, SHOWING AIRCRAFT NUMBER (319), HORIZONTAL STABILIZER, TAIL CONE AND COOLING CTS FOR THE AUXILIARY POWER UNIT (APU), MECHANIC PAUL RIDEOUT IS LOWERING THE BALANCE PANELS ON THE STABILIZERS FOR LUBRICATION AND INSPECTION. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

77 FR 66547 - Approval and Promulgation of Implementation Plans; Michigan; Detroit-Ann Arbor Nonattainment Area...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-06

... 2005 Base Year Emissions Inventory AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is approving the fine particulate matter (PM 2.5 ) 2005 base year emissions inventory, a... 2005 base year emissions inventory for the Detroit-Ann Arbor area. EPA did not receive any comments...

Nyctanthes arbor-tristis Linn--a critical ethnopharmacological review.

PubMed

Agrawal, Jyoti; Pal, Anirban

2013-04-19

Nyctanthes arbor-tristis (Oleaceae) is a mythological plant; has high medicinal values in Ayurveda. The popular medicinal use of this plant are anti-helminthic and anti-pyretic besides its use as a laxative, in rheumatism, skin ailments and as a sedative. Vitally, the natives plant it in their home gardens to pass on its medicinal usage to oncoming generations. The present review encompasses an ethnopharmacological evaluation focusing on information on the chemical constituents, pharmacological actions and toxicology in order to reveal the therapeutic potential and gaps requiring research involvement. The present review is based on searches in Scifinder(®), Pubmed (National Library of Medicine) and books published on the subject during the period 1933 to 2012. Nyctanthes arbor-tristis is most important in local and traditional medicines especially in India for treating intermittent fevers, arthritis and obstinate sciatica. Crude extracts and isolated compounds from the plant were shown to be pharmacologically active against inflammation, malaria, viral infection, leishmanisis and as an immunostimulant. The major class of biologically active compounds are the iridoid glucosides incl., Arbortristoside A, B and C from the seeds active as anticancer, anti-leishmania, anti-inflammatory, anti-allergic, immunomodulatory and antiviral. Other molecules; calceolarioside A, 4-hydroxyhexahydrobenzofuran-7one and β-sitosterol from leaves have been reported to be active as anti-leishmanial, anticancer and anti-inflammatory, respectively. The crude extracts have been found to be safe with an LD50 of 16gm/kg, while the LD50 of arbortristoside-A isolated from the seeds was found to be 0.5g/kg. Mostly in-vitro or in some cases in-vivo models provide some evidence especially in the treatment of inflammatory conditions like arthritis, fevers related to malaria and protozoan diseases especially leishmaniasis. The only clinical study found, is for treating malaria, but with crude

Natural History of the Neotropical Arboreal Ant, Odontomachus hastatus: Nest Sites, Foraging Schedule, and Diet

PubMed Central

Camargo, Rafael X.; Oliveira, Paulo S.

2012-01-01

The ecology of most arboreal ants remains poorly documented because of the difficulty in accessing ant nests and foragers in the forest canopy. This study documents the nesting and foraging ecology of a large (∼13 mm total length) arboreal trap—jaw ant, Odontomachus hastatus (Fabricius) (Hymenoptera: Formicidae) in a sandy plain forest on Cardoso Island, off the coast of Southeast Brazil. The results showed that O. hastatus nested in root clusters of epiphytic bromeliads, most commonly Vriesea procera (70% of nest plants). Mature O. hastatus colonies include one to several queens and about 500 workers. Foraging by O. hastatus is primarily nocturnal year—round, with increased foraging activity during the wet/warm season. The foragers hunt singly in the trees, preying on a variety of canopy—dwelling arthropods, with flies, moths, ants, and spiders accounting for > 60% of the prey captured. Although predators often have impacts on prey populations, the ecological importance of O. hastatus remains to be studied. PMID:22957686

Thyroid Hormone Acts Locally to Increase Neurogenesis, Neuronal Differentiation, and Dendritic Arbor Elaboration in the Tadpole Visual System

PubMed Central

Thompson, Christopher K.

2016-01-01

pregnancy is associated with significant cognitive deficits in humans; however, it is difficult to probe the function of TH in early brain development in mammals because of the inaccessibility of the fetal brain in the uterine environment and the challenge of disambiguating maternal versus fetal contributions of TH. The external development of tadpoles allows manipulation and direct observation of the molecular and cellular mechanisms underlying TH's effects on brain development in ways not possible in mammals. We find that endogenous TH locally regulates neurogenesis at developmental stages relevant to circuit assembly by affecting neural progenitor cell proliferation and differentiation and by acting on neurons to enhance dendritic arbor elaboration. PMID:27707971

Assessment of MRI Contrast Agent Kinetics via Retro-Orbital Injection in Mice: Comparison with Tail Vein Injection.

PubMed

Wang, Fang; Nojima, Masanori; Inoue, Yusuke; Ohtomo, Kuni; Kiryu, Shigeru

2015-01-01

It is not known whether administration of contrast agent via retro-orbital injection or the tail vein route affects the efficiency of dynamic contrast-enhanced magnetic resonance imaging (MRI). Therefore, we compared the effects of retro-orbital and tail vein injection on the kinetics of the contrast agent used for MRI in mice. The same group of nine healthy female mice received contrast agent via either route. An extracellular contrast agent was infused via the tail vein and retro-orbital vein, in random order. Dynamic contrast-enhanced MRI was performed before and after administering the contrast agent. The contrast effects in the liver, kidney, lung, and myocardium were assessed. The average total times of venous puncture and mounting of the injection system were about 10 and 4 min for the tail vein and retro-orbital route, respectively. For all organs assessed, the maximum contrast ratio occurred 30 s after administration and the time course of the contrast ratio was similar with either routes. For each organ, the contrast ratios correlated strongly; the contrast ratios were similar. The retro-orbital and tail vein routes afforded similar results in terms of the kinetics of the contrast agent. The retro-orbital route can be used as a simple efficient alternative to tail vein injection for dynamic contrast-enhanced MRI of mice.

Quadrupedal locomotor performance in two species of arboreal squirrels: predicting energy savings of gliding

Treesearch

Elizabeth A. Flaherty; Merav Ben-David; Winston P. Smith

2010-01-01

Gliding allows mammals to exploit canopy habitats of old-growth forests possibly as a means to save energy. To assess costs of quadrupedal locomotion for a gliding arboreal mammal, we used open-flow respirometry and a variable-speed treadmill to measure oxygen consumption and to calculate cost of transport, excess exercise oxygen consumption, and excess post-exercise...

On the Hydrodynamics of Anomalocaris Tail Fins.

PubMed

Sheppard, K A; Rival, D E; Caron, J-B

2018-04-25

Anomalocaris canadensis, a soft-bodied stem-group arthropod from the Burgess Shale, is considered the largest predator of the Cambrian period. Thanks to a series of lateral flexible lobes along its dorso-ventrally compressed body, it is generally regarded as an efficient swimmer, well-adapted to its predatory lifestyle. Previous theoretical hydrodynamic simulations have suggested a possible optimum in swimming performance when the lateral lobes performed as a single undulatory lateral fin, comparable to the pectoral fins in skates and rays. However, the role of the unusual fan-like tail of Anomalocaris has not been previously explored. Swimming efficiency and maneuverability deduced from direct hydrodynamic analysis are here studied in a towing tank facility using a three-vane physical model designed as an abstraction of the tail fin. Through direct force measurements, it was found that the model exhibited a region of steady-state lift and drag enhancement at angles of attack greater than 25° when compared to a triangular-shaped reference model. This would suggest that the resultant normal force on the tail fin of Anomalocaris made it well-suited for turning maneuvers, giving it the ability to turn quickly and through small radii of curvature. These results are consistent with an active predatory lifestyle, although detailed kinematic studies integrating the full organism, including the lateral lobes, would be required to test the effect of the tail fin on overall swimming performance. This study also highlights a possible example of evolutionary convergence between the tails of Anomalocaris and birds, which, in both cases, are well-adapted to efficient turning maneuvers.

Calcium transient prevalence across the dendritic arbor predicts place field properties

PubMed Central

Sheffield, Mark E. J.; Dombeck, Daniel A.

2014-01-01

Establishing the hippocampal cellular ensemble that represents an animal’s environment involves the emergence and disappearance of place fields in specific CA1 pyramidal neurons1–4, and the acquisition of different spatial firing properties across the active population5. While such firing flexibility and diversity have been linked to spatial memory, attention and task performance6,7, the cellular and network origin of these place cell features is unknown. Basic integrate-and-fire models of place firing propose that such features result solely from varying inputs to place cells8,9, but recent studies3,10 instead suggest that place cells themselves may play an active role through regenerative dendritic events. However, due to the difficulty of performing functional recordings from place cell dendrites, no direct evidence of regenerative dendritic events exists, leaving any possible connection to place coding unknown. Using multi-plane two-photon calcium imaging of CA1 place cell somata, axons, and dendrites in mice navigating a virtual environment, we show that regenerative dendritic events do exist in place cells of behaving mice and, surprisingly, their prevalence throughout the arbor is highly spatiotemporally variable. Further, we show that the prevalence of such events predicts the spatial precision and persistence or disappearance of place fields. This suggests that the dynamics of spiking throughout the dendritic arbor may play a key role in forming the hippocampal representation of space. PMID:25363782

76 FR 36151 - Notice of Inventory Completion: Museum of Anthropology, University of Michigan, Ann Arbor, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-21

... of Anthropology, University of Michigan, Ann Arbor, MI AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The Museum of Anthropology, University of Michigan, has completed an inventory... the Museum of Anthropology, University of Michigan. Repatriation of the human remains to the tribe...

Visual information processing in the lion-tailed macaque (Macaca silenus): mental rotation or rotational invariance?

PubMed

Burmann, Britta; Dehnhardt, Guido; Mauck, Björn

2005-01-01

Mental rotation is a widely accepted concept indicating an image-like mental representation of visual information and an analogue mode of information processing in certain visuospatial tasks. In the task of discriminating between image and mirror-image of rotated figures, human reaction times increase with the angular disparity between the figures. In animals, tests of this kind yield inconsistent results. Pigeons were found to use a time-independent rotational invariance, possibly indicating a non-analogue information processing system that evolved in response to the horizontal plane of reference birds perceive during flight. Despite similar ecological demands concerning the visual reference plane, a sea lion was found to use mental rotation in similar tasks, but its processing speed while rotating three-dimensional stimuli seemed to depend on the axis of rotation in a different way than found for humans in similar tasks. If ecological demands influence the way information processing systems evolve, hominids might have secondarily lost the ability of rotational invariance while retreating from arboreal living and evolving an upright gait in which the vertical reference plane is more important. We therefore conducted mental rotation experiments with an arboreal living primate species, the lion-tailed macaque. Performing a two-alternative matching-to-sample procedure, the animal had to decide between rotated figures representing image and mirror-image of a previously shown upright sample. Although non-rotated stimuli were recognized faster than rotated ones, the animal's mean reaction times did not clearly increase with the angle of rotation. These results are inconsistent with the mental rotation concept but also cannot be explained assuming a mere rotational invariance. Our study thus seems to support the idea of information processing systems evolving gradually in response to specific ecological demands.

76 FR 80392 - Notice of Inventory Completion: University of Michigan Museum of Anthropology, Ann Arbor, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-23

...: University of Michigan Museum of Anthropology, Ann Arbor, MI AGENCY: National Park Service, Interior. ACTION... Michigan officials and its Museum of Anthropology professional staff in consultation with representatives... accessioned into the Museum of Anthropology. Between 2007 and 2009 the remains were inventoried at the...

77 FR 34991 - Notice of Inventory Completion: Museum of Anthropology, University of Michigan, Ann Arbor, MI...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-12

... DEPARTMENT OF THE INTERIOR National Park Service [NPS-WASO-NAGPRA-10375; 2200-1100-665] Notice of Inventory Completion: Museum of Anthropology, University of Michigan, Ann Arbor, MI; Correction AGENCY: National Park Service, Interior. ACTION: Notice; correction. Notice is here given in accordance with the...

Aberrant Axonal Arborization of PDF Neurons Induced by Aβ42-Mediated JNK Activation Underlies Sleep Disturbance in an Alzheimer's Model.

PubMed

Song, Qian; Feng, Ge; Huang, Zehua; Chen, Xiaoman; Chen, Zhaohuan; Ping, Yong

2017-10-01

Impaired sleep patterns are common symptoms of Alzheimer's disease (AD). Cellular mechanisms underlying sleep disturbance in AD remain largely unknown. Here, using a Drosophila Aβ42 AD model, we show that Aβ42 markedly decreases sleep in a large population, which is accompanied with postdevelopmental axonal arborization of wake-promoting pigment-dispersing factor (PDF) neurons. The arborization is mediated in part via JNK activation and can be reversed by decreasing JNK signaling activity. Axonal arborization and impaired sleep are correlated in Aβ42 and JNK kinase hemipterous mutant flies. Image reconstruction revealed that these aberrant fibers preferentially project to pars intercerebralis (PI), a fly brain region analogous to the mammalian hypothalamus. Moreover, PDF signaling in PI neurons was found to modulate sleep/wake activities, suggesting that excessive release of PDF by these aberrant fibers may lead to the impaired sleep in Aβ42 flies. Finally, inhibition of JNK activation in Aβ42 flies restores nighttime sleep loss, decreases Aβ42 accumulation, and attenuates neurodegeneration. These data provide a new mechanism by which sleep disturbance could be induced by Aβ42 burden, a key initiator of a complex pathogenic cascade in AD.

The B7-1 Cytoplasmic Tail Enhances Intracellular Transport and Mammalian Cell Surface Display of Chimeric Proteins in the Absence of a Linear ER Export Motif

PubMed Central

Lin, Yi-Chieh; Chen, Bing-Mae; Lu, Wei-Cheng; Su, Chien-I; Prijovich, Zeljko M.; Chung, Wen-Chuan; Wu, Pei-Yu; Chen, Kai-Chuan; Lee, I-Chiao; Juan, Ting-Yi; Roffler, Steve R.

2013-01-01

Membrane-tethered proteins (mammalian surface display) are increasingly being used for novel therapeutic and biotechnology applications. Maximizing surface expression of chimeric proteins on mammalian cells is important for these applications. We show that the cytoplasmic domain from the B7-1 antigen, a commonly used element for mammalian surface display, can enhance the intracellular transport and surface display of chimeric proteins in a Sar1 and Rab1 dependent fashion. However, mutational, alanine scanning and deletion analysis demonstrate the absence of linear ER export motifs in the B7 cytoplasmic domain. Rather, efficient intracellular transport correlated with the presence of predicted secondary structure in the cytoplasmic tail. Examination of the cytoplasmic domains of 984 human and 782 mouse type I transmembrane proteins revealed that many previously identified ER export motifs are rarely found in the cytoplasmic tail of type I transmembrane proteins. Our results suggest that efficient intracellular transport of B7 chimeric proteins is associated with the structure rather than to the presence of a linear ER export motif in the cytoplasmic tail, and indicate that short (less than ~ 10-20 amino acids) and unstructured cytoplasmic tails should be avoided to express high levels of chimeric proteins on mammalian cells. PMID:24073236

Pb uptake and toxicity to Iris halophila tested on Pb mine tailing materials.

PubMed

Han, Yulin; Zhang, Lili; Yang, Yongheng; Yuan, Haiyan; Zhao, Jiuzhou; Gu, Jiguang; Huang, Suzhen

2016-07-01

Pb tolerant mechanisms, plant physiological response and Pb sub-cellular localization in the root cells of Iris halophila were studied in sand culture and the Pb mine tailings. Results showed that the activities of superoxide dismutase (SOD) and peroxidase (POD) in the underground parts and the activity of catalase (CAT) in the aboveground and underground parts increased as Pb level was enhanced. Glutathione (GSH) and ascorbic acid (AsA) contents increased by Pb treatments. Pb deposits were found in the middle cell walls or along the inner side of epibiotic protoplasm of some cells which accumulated a large quantity of Pb and died. The dry weights (DWs) of aboveground parts under all Pb tailings treatments decreased insignificantly, while the DW of the underground parts growing in the pure Pb tailings decreased significantly. Pb, Cu, Cd, and Zn contents increased significantly as the levels of Pb tailings were enhanced and Pb contents in the aboveground and underground parts reached 64.75 and 751.75 μg/g DW, respectively, at pure Pb tailings treatment. The results indicated that I. halophila is a promising plant in the phytoremediation of Pb contaminated environment. Some antioxidant enzymes, antioxidants and compartmentalization of Pb were played major roles in Pb tolerance of I. halophila. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anisotropic Electron Tail Generation during Tearing Mode Magnetic Reconnection

NASA Astrophysics Data System (ADS)

Dubois, Ami

2017-10-01

Magnetic reconnection (MR) plays an important role in particle transport, energization, and acceleration in space, astrophysical, and laboratory plasmas. In the MST RFP, discrete MR events release large amounts of energy from the equilibrium magnetic field, a large fraction of which is transferred to the ions in a non-collisional process. Key features are anisotropic heating, mass and charge dependence, and energetic ion tail formation. Unlike the ions, the thermal electron temperature decreases at MR events, which is consistent with enhanced electron heat transport due to increased magnetic stochasticity. However, new high-speed x-ray spectrum measurements reveal transient formation of a non-Maxwellian energetic electron tail during MR. The energetic tail is characterized by a power-law, E-γ, with the spectral index (γ) decreasing from 4.2 to 2.2 at MR, and then increasing rapidly to 6.8 due to increased stochastic transport. The x-ray emission peaks in a radial view and is symmetric in the toroidal direction, indicating an anisotropic electron tail is generated. The toroidal symmetry of the electron tail implies runaway acceleration is not a dominant process, consistent with the net emf, ηJll, being smaller than the Dreicer field. Modeling of bremsstrahlung emission shows that a power-law electron tail distribution that is localized near the magnetic axis will yield strong perpendicular anisotropy, consistent with x-ray measurements in the radial and toroidal views. A strong correlation between high energy x-ray flux and tearing mode dynamics suggests a turbulent mechanism is active. This implies that the electron tail formation most likely results from a turbulent wave-particle interaction. This work is supported by the US DOE and NSF.

Discovery of a rare arboreal forest-dwelling flying reptile (Pterosauria, Pterodactyloidea) from China.

PubMed

Wang, Xiaolin; Kellner, Alexander W A; Zhou, Zhonghe; Campos, Diogenes de Almeida

2008-02-12

A previously undescribed toothless flying reptile from northeastern China, Nemicolopterus crypticus gen. et sp. nov., was discovered in the lacustrine sediments of the Early Cretaceous Jiufotang Formation, western Liaoning, China. The specimen consists of an almost complete articulated skeleton (IVPP V14377) and, despite representing an immature individual, based on the ossification of the skeleton, it is not a hatchling or newborn, making it one of the smallest pterosaurs known so far (wing span approximately 250 mm). It can be distinguished from all other pterosaurs by the presence of a short medial nasal process, an inverted "knife-shaped" deltopectoral crest of the humerus, and the presence of a well developed posterior process on the femur above the articulation with the tibia. It further shows the penultimate phalanges of the foot curved in a degree not reported in any pterosaur before, strongly indicating that it had an arboreal lifestyle, more than any other pterodactyloid pterosaur known so far. It is the sister-group of the Ornithocheiroidea and indicates that derived pterosaurs, including some gigantic forms of the Late Cretaceous with wingspans of >6 m, are closely related to small arboreal toothless creatures that likely were living in the canopies of the ancient forests feeding on insects.

A Tale of Two Tails: Exploring Stellar Populations in the Tidal Tails of NGC 3256

NASA Astrophysics Data System (ADS)

Rodruck, Michael; Charlton, Jane C.; Konstantopoulos, Iraklis

2016-01-01

Galaxy interactions can inject material into the intergalactic medium via violent gravitational dynamics, often visualized in tidal tails. The composition of these tails has remained a mystery, as previous studies have focused on detecting tidal features, rather than the composite material itself. We have developed an observing program using deep, multiband imaging to probe the chaotic regions of tidal tails in search for an underlying stellar population. NGC 3256's twin tidal tails serve as a case study for this new technique. Our results show color values of u - g = 1.15 and r - i = 0.08 for the Western tail, and u - g = 1.33 and r - i = 0.22 for the Eastern tail, corresponding to discrepant ages between the tails of approximately 320 Myr and 785 Myr, respectively. With the interaction age of the system measured at 400 Myr, we find the stellar light in Western tail to be dominated by disrupted star clusters formed during and after the interaction, whereas the light from the Eastern tail is dominated by a 10 Gyr population originating from the host galaxies. We fit the Eastern tail color to a Mixed Stellar Population (MSP) model comprised 94% by mass of a 10 Gyr stellar population, and 6% of a 309 Myr population. We find 52% of the bolometric flux originating from this 10 Gyr population. We also detect a blue to red color gradient in each tail, running from galactic center to tail tip. In addition to tidal tail light, we detect 29 star cluster candidates (SCCs) in the Western tail and 19 in the Eastern, with mean ages of 282 Myr and 98 Myr respectively. Interestingly, we find an excess of very blue SCCs in the Eastern tail as compared to the Western tail, marking a recent, small episode of star formation.

Laboratory validation of two real-time RT-PCR methods with 5'-tailed primers for an enhanced detection of foot-and-mouth disease virus.

PubMed

Vandenbussche, Frank; Lefebvre, David J; De Leeuw, Ilse; Van Borm, Steven; De Clercq, Kris

2017-08-01

The 3D and 5UTR real-time RT-PCR assays (RT-qPCR) from Callahan et al. (2002) and Reid et al. (2002) are commonly used reference methods for the detection of foot-and-mouth disease virus (FMDV). For an optimal detection of FMDV in clinical samples, it is advised to use both assays simultaneously (King et al., 2006). Recently, Vandenbussche et al. (2016) showed that the addition of 5'-tails to the FMDV-specific primers enhances the detection of FMDV in both the 3D and the 5UTR RT-qPCR assay. To validate the 3D and 5UTR RT-qPCR assays with 5'-tailed primers for diagnostic purposes, both assays were run in parallel in a triplex one-step RT-qPCR protocol with beta-actin as an internal control and synthetic RNA as an external control. We obtained low limits of detection and high linearity's, high repeatability and reproducibility, near 100% analytical specificity and >99% diagnostic accuracy for both assays. It was concluded that the 3D and 5UTR RT-qPCR assays with 5'-tailed primers are particularly suited for the detection of FMDV as well as to exclude the presence of FMDV. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation Of The Advanced Operating System Of The Ann Arbor Transportation Authority : Evaluation Of Automatic Vehicle Location Accuracy

DOT National Transportation Integrated Search

1999-01-01

In 1997, the Ann Arbor (Michigan) Transportation Authority began deploying advanced public transportation systems (APTS) technologies in its fixed route and paratransit operations. The project's concept is the integration of a range of such technolog...

76 FR 73670 - Notice of Inventory Completion: University of Michigan Museum of Anthropology, Ann Arbor, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-29

...: University of Michigan Museum of Anthropology, Ann Arbor, MI AGENCY: National Park Service, Interior. ACTION... Museum of Anthropology NAGPRA collections staff in consultation with representatives of the Bay Mills... Anthropology purchased the human remains from Reverend L. P. Rowland in November of 1924 as part of a larger...

In vitro antioxidant evaluation and total phenolics of methanolic leaf extracts of Nyctanthes arbor-tristis L.

PubMed

Michael, J Savarimuthu; Kalirajan, A; Padmalatha, C; Singh, A J A Ranjit

2013-09-01

To investigate the in vitro antioxidant activity and total phenolic content of the methanolic leaf extract of Nyctanthes arbor-tristis L. (NA). The sample was tested using five in vitro antioxidant methods (1, 1-diphenyl-2-picryl hydrazine radical scavenging activity (DPPH), hydroxyl radical-scavenging activity (-OH), nitric oxide scavenging activity (NO), superoxide radical-scavenging activity, and total antioxidant activity) to evaluate the in vitro antioxidant potential of NA and the total phenolic content (Folin-Ciocalteu method). The extract showed good free radical scavenging property which was calculated as an IC50 value. IC50 (Half maximal inhibitory concentration) of the methanolic extract was found to be 57.93 μg·mL(-1) for DPPH, 98.61 μg·mL(-1) for -OH, 91.74 μg·mL(-1) for NO, and 196.07 μg·mL(-1) for superoxide radical scavenging activity. Total antioxidant capacity of the extract was found to be (1198 ± 24.05) mg ascorbic acid for the methanolic extract. Free radical scavenging activity observed in the extracts of NA showed a concentration-dependent reaction. The in vitro scavenging tested for free radicals was reported to be due to high phenolic content in the leaf extract. The leaf extract of NA showed the highest total phenolic content with a value of 78.48 ± 4.2 equivalent mg TAE/g (tannic acid equivalent). N. arbor-tristis leaf extract exhibited potent free radical scavenging activity. The finding suggests that N. arbor-tristis leaves could be a potential source of natural antioxidant. Copyright © 2013 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Impact of the Motor and Tail Domains of Class III Myosins on Regulating the Formation and Elongation of Actin Protrusions*

PubMed Central

Quintero, Omar A.; Weck, Meredith L.; Unrath, William C.; Gallagher, James W.; Cui, Runjia; Kachar, Bechara; Tyska, Matthew J.; Yengo, Christopher M.

2016-01-01

Class III myosins (MYO3A and MYO3B) are proposed to function as transporters as well as length and ultrastructure regulators within stable actin-based protrusions such as stereocilia and calycal processes. MYO3A differs from MYO3B in that it contains an extended tail domain with an additional actin-binding motif. We examined how the properties of the motor and tail domains of human class III myosins impact their ability to enhance the formation and elongation of actin protrusions. Direct examination of the motor and enzymatic properties of human MYO3A and MYO3B revealed that MYO3A is a 2-fold faster motor with enhanced ATPase activity and actin affinity. A chimera in which the MYO3A tail was fused to the MYO3B motor demonstrated that motor activity correlates with formation and elongation of actin protrusions. We demonstrate that removal of individual exons (30–34) in the MYO3A tail does not prevent filopodia tip localization but abolishes the ability to enhance actin protrusion formation and elongation in COS7 cells. Interestingly, our results demonstrate that MYO3A slows filopodia dynamics and enhances filopodia lifetime in COS7 cells. We also demonstrate that MYO3A is more efficient than MYO3B at increasing formation and elongation of stable microvilli on the surface of cultured epithelial cells. We propose that the unique features of MYO3A, enhanced motor activity, and an extended tail with tail actin-binding motif, allow it to play an important role in stable actin protrusion length and ultrastructure maintenance. PMID:27582493

Practice makes perfect: Performance optimisation in 'arboreal' parkour athletes illuminates the evolutionary ecology of great ape anatomy.

PubMed

Halsey, Lewis G; Coward, Samuel R L; Crompton, Robin H; Thorpe, Susannah K S

2017-02-01

An animal's size is central to its ecology, yet remarkably little is known about the selective pressures that drive this trait. A particularly compelling example is how ancestral apes evolved large body mass in such a physically and energetically challenging environment as the forest canopy, where weight-bearing branches and lianas are flexible, irregular and discontinuous, and the majority of preferred foods are situated on the most flexible branches at the periphery of tree crowns. To date the issue has been intractable due to a lack of relevant fossil material, the limited capacity of the fossil record to reconstruct an animal's behavioural ecology and the inability to measure energy consumption in freely moving apes. We studied the oxygen consumption of parkour athletes while they traversed an arboreal-like course as an elite model ape, to test the ecomorphological and behavioural mechanisms by which a large-bodied ape could optimize its energetic performance during tree-based locomotion. Our results show that familiarity with the arboreal-like course allowed the athletes to substantially reduce their energy expenditure. Furthermore, athletes with larger arm spans and shorter legs were particularly adept at finding energetic savings. Our results flesh out the scanty fossil record to offer evidence that long, strong arms, broad chests and a strong axial system, combined with the frequent use of uniform branch-to-branch arboreal pathways, were critical to off-setting the mechanical and energetic demands of large mass in ancestral apes. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Contour variations of the body and tail of the pancreas: evaluation with MDCT.

PubMed

Omeri, Ahmad Khalid; Matsumoto, Shunro; Kiyonaga, Maki; Takaji, Ryo; Yamada, Yasunari; Kosen, Kazuhisa; Mori, Hiromu; Miyake, Hidetoshi

2017-06-01

To analyze morphology/contour variations of the pancreatic body and tail in subjects free of pancreatic disease. We retrospectively reviewed triple-phase, contrast-enhanced multi-detector row computed tomography (3P-CE-MDCT) examinations of 449 patients who had no clinical or CT evidence of pancreatic diseases. These patients were evaluated for morphologic/contour variations of the pancreatic body and tail, which were classified into two types. In Type I, a portion of normal pancreatic parenchyma protrudes >1 cm in maximum diameter from the body or tail (Ia-anteriorly; Ib-posteriorly). Type II was defined as a morphologic anomaly of the pancreatic tail (IIa-globular; IIb-lobulated; IIc-tapered; IId-bifid). Thirty-eight (8.5%) out of 449 patients had body or tail variations. Of those, 23 patients showed Type I variant: Ia in 21 and Ib in two. Type II variant was identified in 15 patients: IIa in eight, IIb in two, IIc in two and IId in three. Protrusion of the anterior surface of the normal pancreas, especially in the tail, was the most frequently occurring variant. Recognizing the types and subtypes of morphology/contour variations of the pancreatic body and tail could help prevent misinterpretation of normal variants as pancreatic tumors on unenhanced MDCT.

SAD kinases sculpt axonal arbors of sensory neurons through long and short-term responses to neurotrophin signals

PubMed Central

Lilley, Brendan N.; Pan, Y. Albert; Sanes, Joshua R.

2013-01-01

SUMMARY Extrinsic cues activate intrinsic signaling mechanisms to pattern neuronal shape and connectivity. We showed previously that three cytoplasmic Ser/Thr kinases, LKB1, SAD-A and SAD-B, control early axon-dendrite polarization in forebrain neurons. Here we assess their role in other neuronal types. We found that all three kinases are dispensable for axon formation outside of the cortex, but that SAD kinases are required for formation of central axonal arbors by subsets of sensory neurons. The requirement for SAD kinases is most prominent in NT-3 dependent neurons. SAD kinases transduce NT-3 signals in two ways through distinct pathways. First, sustained NT-3/TrkC signaling increases SAD protein levels. Second, short duration NT-3/TrkC signals transiently activate SADs by inducing dephosphorylation of C-terminal domains, thereby allowing activating phosphorylation of the kinase domain. We propose that SAD kinases integrate long- and short duration signals from extrinsic cues to sculpt axon arbors within the CNS. PMID:23790753

A passerine spreads its tail to facilitate a rapid recovery of its body posture during hovering

PubMed Central

Su, Jian-Yuan; Ting, Shang-Chieh; Chang, Yu-Hung; Yang, Jing-Tang

2012-01-01

We demonstrate experimentally that a passerine exploits tail spreading to intercept the downward flow induced by its wings to facilitate the recovery of its posture. The periodic spreading of its tail by the White-eye bird exhibits a phase correlation with both wingstroke motion and body oscillation during hovering flight. During a downstroke, a White-eye's body undergoes a remarkable pitch-down motion, with the tail undergoing an upward swing. This pitch-down motion becomes appropriately suppressed at the end of the downstroke; the bird's body posture then recovers gradually to its original status. Employing digital particle-image velocimetry, we show that the strong downward flow induced by downstroking the wings serves as an external jet flow impinging upon the tail, providing a depressing force on the tail to counteract the pitch-down motion of the bird's body. Spreading of the tail enhances a rapid recovery of the body posture because increased forces are experienced. The maximum force experienced by a spread tail is approximately 2.6 times that of a non-spread tail. PMID:22258552

A passerine spreads its tail to facilitate a rapid recovery of its body posture during hovering.

PubMed

Su, Jian-Yuan; Ting, Shang-Chieh; Chang, Yu-Hung; Yang, Jing-Tang

2012-07-07

We demonstrate experimentally that a passerine exploits tail spreading to intercept the downward flow induced by its wings to facilitate the recovery of its posture. The periodic spreading of its tail by the White-eye bird exhibits a phase correlation with both wingstroke motion and body oscillation during hovering flight. During a downstroke, a White-eye's body undergoes a remarkable pitch-down motion, with the tail undergoing an upward swing. This pitch-down motion becomes appropriately suppressed at the end of the downstroke; the bird's body posture then recovers gradually to its original status. Employing digital particle-image velocimetry, we show that the strong downward flow induced by downstroking the wings serves as an external jet flow impinging upon the tail, providing a depressing force on the tail to counteract the pitch-down motion of the bird's body. Spreading of the tail enhances a rapid recovery of the body posture because increased forces are experienced. The maximum force experienced by a spread tail is approximately 2.6 times that of a non-spread tail.

A transgenic reporter under control of an es1 promoter/enhancer marks wound epidermis and apical epithelial cap during tail regeneration in Xenopus laevis tadpole.

PubMed

Sato, Kentaro; Umesono, Yoshihiko; Mochii, Makoto

2018-01-15

Rapid wound healing and subsequent formation of the apical epithelial cap (AEC) are believed to be required for successful appendage regeneration in amphibians. Despite the significant role of AEC in limb regeneration, its role in tail regeneration and the mechanisms that regulate the wound healing and AEC formation are not well understood. We previously identified Xenopus laevis es1, which is preferentially expressed in wounded regions, including the AEC after tail regeneration. In this study we established and characterized transgenic Xenopus laevis lines harboring the enhanced green fluorescent protein (EGFP) gene under control of an es1 gene regulatory sequence (es1:egfp). The EGFP reporter expression was clearly seen in several regions of the embryo and then declined to an undetectable level in larvae, recapitulating the endogenous es1 expression. After amputation of the tadpole tail, EGFP expression was re-activated at the edge of the stump epidermis and then increased in the wound epidermis (WE) covering the amputation surface. As the stump started to regenerate, the EGFP expression became restricted to the most distal epidermal region, including the AEC. EGFP was preferentially expressed in the basal or deep cells but not in the superficial cells of the WE and AEC. We performed a small-scale pharmacological screening for chemicals that affected the expression of EGFP in the stump epidermis after tail amputation. The EGFP expression was attenuated by treatment with an inhibitor for ERK, TGF-β or reactive oxygen species (ROS) signaling. These treatments also impaired wound closure of the amputation surface, suggesting that the three signaling activities are required for es1 expression in the WE and successful wound healing after tail amputation. These findings showed that es1:egfp Xenopus laevis should be a useful tool to analyze molecular mechanisms regulating wound healing and appendage regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Dendritic Arborization and Spine Dynamics Are Abnormal in the Mouse Model of MECP2 Duplication Syndrome

PubMed Central

Jiang, Minghui; Ash, Ryan T.; Baker, Steven A.; Suter, Bernhard; Ferguson, Andrew; Park, Jiyoung; Rudy, Jessica; Torsky, Sergey P.; Chao, Hsiao-Tuan; Zoghbi, Huda Y.

2013-01-01

MECP2 duplication syndrome is a childhood neurological disorder characterized by intellectual disability, autism, motor abnormalities, and epilepsy. The disorder is caused by duplications spanning the gene encoding methyl-CpG-binding protein-2 (MeCP2), a protein involved in the modulation of chromatin and gene expression. MeCP2 is thought to play a role in maintaining the structural integrity of neuronal circuits. Loss of MeCP2 function causes Rett syndrome and results in abnormal dendritic spine morphology and decreased pyramidal dendritic arbor complexity and spine density. The consequences of MeCP2 overexpression on dendritic pathophysiology remain unclear. We used in vivo two-photon microscopy to characterize layer 5 pyramidal neuron spine turnover and dendritic arborization as a function of age in transgenic mice expressing the human MECP2 gene at twice the normal levels of MeCP2 (Tg1; Collins et al., 2004). We found that spine density in terminal dendritic branches is initially higher in young Tg1 mice but falls below control levels after postnatal week 12, approximately correlating with the onset of behavioral symptoms. Spontaneous spine turnover rates remain high in older Tg1 animals compared with controls, reflecting the persistence of an immature state. Both spine gain and loss rates are higher, with a net bias in favor of spine elimination. Apical dendritic arbors in both simple- and complex-tufted layer 5 Tg1 pyramidal neurons have more branches of higher order, indicating that MeCP2 overexpression induces dendritic overgrowth. P70S6K was hyperphosphorylated in Tg1 somatosensory cortex, suggesting that elevated mTOR signaling may underlie the observed increase in spine turnover and dendritic growth. PMID:24336718

High-energy tail distributions and resonant wave particle interaction

NASA Technical Reports Server (NTRS)

Leubner, M. P.

1983-01-01

High-energy tail distributions (k distributions) are used as an alternative to a bi-Lorentzian distribution to study the influence of energetic protons on the right- and left-hand cyclotron modes in a hot two-temperature plasma. Although the parameters are chosen to be in a range appropriate to solar wind or magnetospheric configurations, the results apply not only to specific space plasmas. The presence of energetic particles significantly alters the behavior of the electromagnetic ion cyclotron modes, leading to a wide range of unstable frequencies and increased growth rates. From the strongly enhanced growth rates it can be concluded that high-energy tail distributions should not show major temperature anisotropies, which is consistent with observations.

Nyctanthes arbor-tristis Ameliorated FCA-Induced Experimental Arthritis: A Comparative Study among Different Extracts

PubMed Central

Uroos, Maliha; Sattar, Shumaila; Umer, Nigarish; Sharif, Ahsan

2017-01-01

Nyctanthes arbor-tristis (NAT) is commonly used traditionally for the treatment of rheumatism and inflammatory diseases. Current study evaluates the antiarthritic potential of NAT using Freund's adjuvant-induced arthritic rat model. Treatments with methanolic, ethyl acetate, and n-hexane extracts were continued for consecutive 20 days. Macroscopic arthritic scoring and water displacement plethysmometry were used to evaluate arthritic development. Hematological and biochemical parameters were investigated and ankle joints were processed for histopathological evaluation. Qualitative phytochemical analysis and GC-MS analysis were conducted for identification of constituents. NAT extracts suppressed arthritic scoring, paw edema, infiltration of inflammatory cells, pannus formation, and bone erosion. The plant extracts ameliorated total leukocytes and platelet counts and nearly normalized red blood cells (RBC) counts and hemoglobin (Hb) content. The extracts were found safe in terms of hepatotoxicity and nephrotoxicity as determined by aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and urea levels. Comparative analysis showed that ethyl acetate extract produced the highest inhibition of paw edema. The major constituents found in ethyl acetate extract can be classified into three major classes, that is, terpenes, terpenoids, fatty acids, and iridoid glycosides. Current study showed that Nyctanthes arbor-tristis ameliorated experimental rheumatoid arthritis and ethyl acetate extract possessed the highest inhibitory activity. PMID:28676830

Tracking individual action potentials throughout mammalian axonal arbors.

PubMed

Radivojevic, Milos; Franke, Felix; Altermatt, Michael; Müller, Jan; Hierlemann, Andreas; Bakkum, Douglas J

2017-10-09

Axons are neuronal processes specialized for conduction of action potentials (APs). The timing and temporal precision of APs when they reach each of the synapses are fundamentally important for information processing in the brain. Due to small diameters of axons, direct recording of single AP transmission is challenging. Consequently, most knowledge about axonal conductance derives from modeling studies or indirect measurements. We demonstrate a method to noninvasively and directly record individual APs propagating along millimeter-length axonal arbors in cortical cultures with hundreds of microelectrodes at microsecond temporal resolution. We find that cortical axons conduct single APs with high temporal precision (~100 µs arrival time jitter per mm length) and reliability: in more than 8,000,000 recorded APs, we did not observe any conduction or branch-point failures. Upon high-frequency stimulation at 100 Hz, successive became slower, and their arrival time precision decreased by 20% and 12% for the 100th AP, respectively.

Wind-tunnel Investigation of End-plate Effects of Horizontal Tails on a Vertical Tail Compared with Available Theory

NASA Technical Reports Server (NTRS)

Murray, Harry E

1946-01-01

A vertical-tail model with stub fuselage was tested in combination with various simulated horizontal tails to determine the effect of horizontal-tail span and location on the aerodynamic characteristics of the vertical tail. Available theoretical data on end-plate effects were collected and presented in the form most suitable for design purposes. Reasonable agreement was obtained between the measured and theoretical end-plate effects of horizontal tails on vertical tails, and the data indicated that the end-plate effect was determined more by the location of the horizontal tail than by the span of the horizontal tail. The horizontal tail gave most end-plate effect when located near either tip of the vertical tail and, when located near the base of the vertical tail, the end-plate effect was increased by moving the horizontal tail rearward.

MESSENGER Observations of Extreme Magnetic Tail Loading and Unloading during its Third Flyby of Mercury: Substorms?

NASA Astrophysics Data System (ADS)

Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Gloeckler, George; Krimigis, Stamatios M.; McNutt, Ralph L., Jr.; Schriver, David; Solomon, Sean C.; Zurbuchen, Thomas H.

2010-05-01

During MESSENGER's third flyby of Mercury on September 29, 2009, a variable interplanetary magnetic field produced a series of several minute enhancements of the tail magnetic field by factors of ~ 2 to 3.5. The magnetic field flaring during these intervals indicates that they result from loading of the tail with magnetic flux transferred from the dayside magnetosphere. The unloading intervals were associated with plasmoids and traveling compression regions which are well known signatures of tail reconnection. The peak tail magnetic flux during the smallest loading events equaled 30% of the magnetic flux emanating from Mercury, and may have reached 100% for the largest event. In this case the dayside magnetic shielding is reduced and solar wind flux impacting the surface may be greatly enhanced. Despite the intensity of these events and their similarity to terrestrial substorm magnetic flux dynamics, no energetic charged particles with energies greater than 36 keV were observed. This absence of energetic particles constitutes a deepening puzzle for the view that the Mercury magnetosphere system is undergoing dynamical processes analogous to those at Earth during substorm events.

The Tail Suspension Test

PubMed Central

Terrillion, Chantelle E.; Piantadosi, Sean C.; Bhat, Shambhu; Gould, Todd D.

2012-01-01

The tail-suspension test is a mouse behavioral test useful in the screening of potential antidepressant drugs, and assessing of other manipulations that are expected to affect depression related behaviors. Mice are suspended by their tails with tape, in such a position that it cannot escape or hold on to nearby surfaces. During this test, typically six minutes in duration, the resulting escape oriented behaviors are quantified. The tail-suspension test is a valuable tool in drug discovery for high-throughput screening of prospective antidepressant compounds. Here, we describe the details required for implementation of this test with additional emphasis on potential problems that may occur and how to avoid them. We also offer a solution to the tail climbing behavior, a common problem that renders this test useless in some mouse strains, such as the widely used C57BL/6. Specifically, we prevent tail climbing behaviors by passing mouse tails through a small plastic cylinder prior to suspension. Finally, we detail how to manually score the behaviors that are manifested in this test. PMID:22315011

The fish tail motion forms an attached leading edge vortex

PubMed Central

Borazjani, Iman; Daghooghi, Mohsen

2013-01-01

The tail (caudal fin) is one of the most prominent characteristics of fishes, and the analysis of the flow pattern it creates is fundamental to understanding how its motion generates locomotor forces. A mechanism that is known to greatly enhance locomotor forces in insect and bird flight is the leading edge vortex (LEV) reattachment, i.e. a vortex (separation bubble) that stays attached at the leading edge of a wing. However, this mechanism has not been reported in fish-like swimming probably owing to the overemphasis on the trailing wake, and the fact that the flow does not separate along the body of undulating swimmers. We provide, to our knowledge, the first evidence of the vortex reattachment at the leading edge of the fish tail using three-dimensional high-resolution numerical simulations of self-propelled virtual swimmers with different tail shapes. We show that at Strouhal numbers (a measure of lateral velocity to the axial velocity) at which most fish swim in nature (approx. 0.25) an attached LEV is formed, whereas at a higher Strouhal number of approximately 0.6 the LEV does not reattach. We show that the evolution of the LEV drastically alters the pressure distribution on the tail and the force it generates. We also show that the tail's delta shape is not necessary for the LEV reattachment and fish-like kinematics is capable of stabilising the LEV. Our results suggest the need for a paradigm shift in fish-like swimming research to turn the focus from the trailing edge to the leading edge of the tail. PMID:23407826

Biota of uranium mill tailings near the Black Hills

Treesearch

Mark A. Rumble

1982-01-01

Reclamation" often implies the enhancement of the land as wildlife habitat or for other productive uses. However, there are situations where revegetation to stabilize erosion is the only desired goal. Uranium mining and mill sites may fall into this later category. Data pertaining to plant and animal components on revegetated uranium mill tailings was collected....

The tail of the ParG DNA segregation protein remodels ParF polymers and enhances ATP hydrolysis via an arginine finger-like motif

PubMed Central

Barillà, Daniela; Carmelo, Emma; Hayes, Finbarr

2007-01-01

The ParF protein of plasmid TP228 belongs to the ubiquitous superfamily of ParA ATPases that drive DNA segregation in bacteria. ATP-bound ParF polymerizes into multistranded filaments. The partner protein ParG is dimeric, consisting of C-termini that interweave into a ribbon–helix–helix domain contacting the centromeric DNA and unstructured N-termini. ParG stimulates ATP hydrolysis by ParF ≈30-fold. Here, we establish that the mobile tails of ParG are crucial for this enhancement and that arginine R19 within the tail is absolutely required for activation of ParF nucleotide hydrolysis. R19 is part of an arginine finger-like loop in ParG that is predicted to intercalate into the ParF nucleotide-binding pocket thereby promoting ATP hydrolysis. Significantly, mutations of R19 abrogated DNA segregation in vivo, proving that intracellular stimulation of ATP hydrolysis by ParG is a key regulatory process for partitioning. Furthermore, ParG bundles ParF-ATP filaments as well as promoting nucleotide-independent polymerization. The N-terminal flexible tail is required for both activities, because N-terminal ΔParG polypeptides are defective in both functions. Strikingly, the critical arginine finger-like residue R19 is dispensable for ParG-mediated remodeling of ParF polymers, revealing that the ParG N-terminal tail possesses two separable activities in the interplay with ParF: a catalytic function during ATP hydrolysis and a mechanical role in modulation of polymerization. We speculate that activation of nucleotide hydrolysis via an arginine finger loop may be a conserved, regulatory mechanism of ParA family members and their partner proteins, including ParA-ParB and Soj-Spo0J that mediate DNA segregation and MinD-MinE that determine septum localization. PMID:17261809

The tail of the ParG DNA segregation protein remodels ParF polymers and enhances ATP hydrolysis via an arginine finger-like motif.

PubMed

Barillà, Daniela; Carmelo, Emma; Hayes, Finbarr

2007-02-06

The ParF protein of plasmid TP228 belongs to the ubiquitous superfamily of ParA ATPases that drive DNA segregation in bacteria. ATP-bound ParF polymerizes into multistranded filaments. The partner protein ParG is dimeric, consisting of C-termini that interweave into a ribbon-helix-helix domain contacting the centromeric DNA and unstructured N-termini. ParG stimulates ATP hydrolysis by ParF approximately 30-fold. Here, we establish that the mobile tails of ParG are crucial for this enhancement and that arginine R19 within the tail is absolutely required for activation of ParF nucleotide hydrolysis. R19 is part of an arginine finger-like loop in ParG that is predicted to intercalate into the ParF nucleotide-binding pocket thereby promoting ATP hydrolysis. Significantly, mutations of R19 abrogated DNA segregation in vivo, proving that intracellular stimulation of ATP hydrolysis by ParG is a key regulatory process for partitioning. Furthermore, ParG bundles ParF-ATP filaments as well as promoting nucleotide-independent polymerization. The N-terminal flexible tail is required for both activities, because N-terminal DeltaParG polypeptides are defective in both functions. Strikingly, the critical arginine finger-like residue R19 is dispensable for ParG-mediated remodeling of ParF polymers, revealing that the ParG N-terminal tail possesses two separable activities in the interplay with ParF: a catalytic function during ATP hydrolysis and a mechanical role in modulation of polymerization. We speculate that activation of nucleotide hydrolysis via an arginine finger loop may be a conserved, regulatory mechanism of ParA family members and their partner proteins, including ParA-ParB and Soj-Spo0J that mediate DNA segregation and MinD-MinE that determine septum localization.

The formation and potential importance of cemented layers in inactive sulfide mine tailings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blowes, D.W.; Reardon, E.J.; Cherry, J.A.

Investigations of inactive sulfide-rich tailings impoundments at the Heath Steele (New Brunswick) and Waite Amulet (Quebec) minesites have revealed two distinct types of cemented layers or hardpans. That at Heath Steele is 10-15 cm thick, occurs 20-30 cm below the depth of active oxidation, is continuous throughout the tailings impoundment, and is characterized by cementation of tailings by gypsum and Fe(II) solid phases, principally melanterite. Hardpan at the Waite Amulet site is only 1-5 cm thick, is laterally discontinuous (10-100 cm), occurs at the depth of active oxidation, and is characterized by cementation of tailings by Fe(III) minerals, principally goethite,more » lepidocrocite, ferrihydrite, and jarosite. At Heath Steele, an accumulation of gas-phase CO{sub 2}, of up to 60{percent} of the pore gas, occurs below the hardpan. The calculated diffusivity of the hardpan layer is only about 1/100 that of the overlying, uncemented tailings. The pore-water chemistry at Heath Steele has changed little over a 10-year period, suggesting that the cemented layer restricts the movement of dissolved metals through the tailings and also acts as a zone of metal accumulation. Generation of a cemented layer therefore has significant environmental and economic implications. It is likely that, in sulfide-rich tailings impoundments, the addition of carbonate-rich buffering material during the late stages of tailings deposition would enhance the formation of hardpan layers.« less

Sharp-tailed Grouse Restoration; Colville Tribes Restore Habitat for Sharp-tailed Grouse, Annual Report 2002-2003.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whitney, Richard

2004-01-01

Columbian Sharp-Tailed Grouse (Tympanuchus phasianellus columbianus) (CSTG) are an important traditional and cultural species to the Colville Confederated Tribes (CCT), Spokane Tribe of Indians (STOI), and other Tribes in the Region. They were once the most abundant upland bird in the Region. Currently, the largest remaining population in Washington State occurs on the CCT Reservation in Okanogan County. Increasing agricultural practices and other land uses has contributed to the decline of sharp-tail habitat and populations putting this species at risk. The decline of this species is not new (Yokum, 1952, Buss and Dziedzic, 1955, Zeigler, 1979, Meints 1991, and Crawfordmore » and Snyder 1994). The Tribes (CCT and STOI) are determined to protect, enhance and restore habitat for this species continued existence. When Grand Coulee and Chief Joseph Hydro-projects were constructed, inundated habitat used by this species was lost forever adding to overall decline. To compensate and prevent further habitat loss, the CCT proposed a project with Bonneville Power Administration (BPA) funding to address this species and their habitat requirements. The projects main focus is to address habitat utilized by the current CSTG population and determine ways to protect, restore, and enhance habitats for the conservation of this species over time. The project went through the NPPC Review Process and was funded through FY03 by BPA. This report addresses part of the current CCT effort to address the conservation of this species on the Colville Reservation.« less

Morphology and function of the forelimb in arboreal frogs: specializations for grasping ability?

PubMed Central

Manzano, Adriana S; Abdala, Virginia; Herrel, Anthony

2008-01-01

Frogs are characterized by a unique morphology associated with their saltatory lifestyle. Although variation in the form and function of the pelvic girdle and associated appendicular system related to specialized locomotor modes such as swimming or burrowing has been documented, the forelimbs have typically been viewed as relatively unspecialized. Yet, previous authors have noted versatility in forelimb function among arboreal frogs associated with feeding. Here we study the morphology and function of the forelimb and hand during locomotion in two species of arboreal frogs (Litoria caerulea and Phyllomedusa bicolor). Our data show a complex arrangement of the distal forelimb and hand musculature with some notable differences between species. Analyses of high-speed video and video fluoroscopy recordings show that forelimbs are used in alternating fashion in a diagonal sequence footfall pattern and that the position of the hand is adjusted when walking on substrates of different diameters. Electromyographic recordings show that the flexors of the hand are active during substrate contact, suggesting the use of gripping to generate a stabilizing torque. Measurements of grasping forces in vivo and during stimulation experiments show that both species, are capable of executing a so-called power grip but also indicates marked differences between species, in the magnitude of forces generated. Stimulation experiments showed an increased control of digit flexion in the more specialized of the two species, allowing it to execute a precision grip paralleled only by that seen in primates. PMID:18565111

Morphology and function of the forelimb in arboreal frogs: specializations for grasping ability?

PubMed

Manzano, Adriana S; Abdala, Virginia; Herrel, Anthony

2008-09-01

Frogs are characterized by a unique morphology associated with their saltatory lifestyle. Although variation in the form and function of the pelvic girdle and associated appendicular system related to specialized locomotor modes such as swimming or burrowing has been documented, the forelimbs have typically been viewed as relatively unspecialized. Yet, previous authors have noted versatility in forelimb function among arboreal frogs associated with feeding. Here we study the morphology and function of the forelimb and hand during locomotion in two species of arboreal frogs (Litoria caerulea and Phyllomedusa bicolor). Our data show a complex arrangement of the distal forelimb and hand musculature with some notable differences between species. Analyses of high-speed video and video fluoroscopy recordings show that forelimbs are used in alternating fashion in a diagonal sequence footfall pattern and that the position of the hand is adjusted when walking on substrates of different diameters. Electromyographic recordings show that the flexors of the hand are active during substrate contact, suggesting the use of gripping to generate a stabilizing torque. Measurements of grasping forces in vivo and during stimulation experiments show that both species, are capable of executing a so-called power grip but also indicates marked differences between species, in the magnitude of forces generated. Stimulation experiments showed an increased control of digit flexion in the more specialized of the two species, allowing it to execute a precision grip paralleled only by that seen in primates.

Disentangling the diversity of arboreal ant communities in tropical forest trees.

PubMed

Klimes, Petr; Fibich, Pavel; Idigel, Cliffson; Rimandai, Maling

2015-01-01

Tropical canopies are known for their high abundance and diversity of ants. However, the factors which enable coexistence of so many species in trees, and in particular, the role of foragers in determining local diversity, are not well understood. We censused nesting and foraging arboreal ant communities in two 0.32 ha plots of primary and secondary lowland rainforest in New Guinea and explored their species diversity and composition. Null models were used to test if the records of species foraging (but not nesting) in a tree were dependent on the spatial distribution of nests in surrounding trees. In total, 102 ant species from 389 trees occurred in the primary plot compared with only 50 species from 295 trees in the secondary forest plot. However, there was only a small difference in mean ant richness per tree between primary and secondary forest (3.8 and 3.3 sp. respectively) and considerably lower richness per tree was found only when nests were considered (1.5 sp. in both forests). About half of foraging individuals collected in a tree belonged to species which were not nesting in that tree. Null models showed that the ants foraging but not nesting in a tree are more likely to nest in nearby trees than would be expected at random. The effects of both forest stage and tree size traits were similar regardless of whether only foragers, only nests, or both datasets combined were considered. However, relative abundance distributions of species differed between foraging and nesting communities. The primary forest plot was dominated by native ant species, whereas invasive species were common in secondary forest. This study demonstrates the high contribution of foragers to arboreal ant diversity, indicating an important role of connectivity between trees, and also highlights the importance of primary vegetation for the conservation of native ant communities.

Disentangling the Diversity of Arboreal Ant Communities in Tropical Forest Trees

PubMed Central

Klimes, Petr; Fibich, Pavel; Idigel, Cliffson; Rimandai, Maling

2015-01-01

Tropical canopies are known for their high abundance and diversity of ants. However, the factors which enable coexistence of so many species in trees, and in particular, the role of foragers in determining local diversity, are not well understood. We censused nesting and foraging arboreal ant communities in two 0.32 ha plots of primary and secondary lowland rainforest in New Guinea and explored their species diversity and composition. Null models were used to test if the records of species foraging (but not nesting) in a tree were dependent on the spatial distribution of nests in surrounding trees. In total, 102 ant species from 389 trees occurred in the primary plot compared with only 50 species from 295 trees in the secondary forest plot. However, there was only a small difference in mean ant richness per tree between primary and secondary forest (3.8 and 3.3 sp. respectively) and considerably lower richness per tree was found only when nests were considered (1.5 sp. in both forests). About half of foraging individuals collected in a tree belonged to species which were not nesting in that tree. Null models showed that the ants foraging but not nesting in a tree are more likely to nest in nearby trees than would be expected at random. The effects of both forest stage and tree size traits were similar regardless of whether only foragers, only nests, or both datasets combined were considered. However, relative abundance distributions of species differed between foraging and nesting communities. The primary forest plot was dominated by native ant species, whereas invasive species were common in secondary forest. This study demonstrates the high contribution of foragers to arboreal ant diversity, indicating an important role of connectivity between trees, and also highlights the importance of primary vegetation for the conservation of native ant communities. PMID:25714831

Automatic early warning of tail biting in pigs: 3D cameras can detect lowered tail posture before an outbreak

PubMed Central

Jack, Mhairi; Futro, Agnieszka; Talbot, Darren; Zhu, Qiming; Barclay, David; Baxter, Emma M.

2018-01-01

Tail biting is a major welfare and economic problem for indoor pig producers worldwide. Low tail posture is an early warning sign which could reduce tail biting unpredictability. Taking a precision livestock farming approach, we used Time-of-flight 3D cameras, processing data with machine vision algorithms, to automate the measurement of pig tail posture. Validation of the 3D algorithm found an accuracy of 73.9% at detecting low vs. not low tails (Sensitivity 88.4%, Specificity 66.8%). Twenty-three groups of 29 pigs per group were reared with intact (not docked) tails under typical commercial conditions over 8 batches. 15 groups had tail biting outbreaks, following which enrichment was added to pens and biters and/or victims were removed and treated. 3D data from outbreak groups showed the proportion of low tail detections increased pre-outbreak and declined post-outbreak. Pre-outbreak, the increase in low tails occurred at an increasing rate over time, and the proportion of low tails was higher one week pre-outbreak (-1) than 2 weeks pre-outbreak (-2). Within each batch, an outbreak and a non-outbreak control group were identified. Outbreak groups had more 3D low tail detections in weeks -1, +1 and +2 than their matched controls. Comparing 3D tail posture and tail injury scoring data, a greater proportion of low tails was associated with more injured pigs. Low tails might indicate more than just tail biting as tail posture varied between groups and over time and the proportion of low tails increased when pigs were moved to a new pen. Our findings demonstrate the potential for a 3D machine vision system to automate tail posture detection and provide early warning of tail biting on farm. PMID:29617403

Heavy metal leaching from mine tailings as affected by plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, D.; Schwab, A.P.; Banks, M.K.

A column experiment was conducted to determine the impact of soil cover and plants on heavy metal leaching from mine tailings and heavy metal contaminated soil. Columns made of PVC were constructed with 30 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm of clean topsoil. Two grasses, tall fescue (Festuca arundinacea Schreb.) and big bluestem (Andropogon gerardii), were grown in the columns. The columns were leached at a slow rate for 1 yr with a 0.001 Mmore » CaCl{sub 2} solution under unsaturated conditions. The presence of both tall fescue and big bluestem increased Zn and Cd concentrations in the leachate. Lead concentrations in leachates were not affected by the presence of plants. Although plants generally reduced the total amount of water leached, total mass of Zn and Cd leached generally was not impacted by plants. Total mass of Pb leached was positively correlated with total leachate collected from each column. Covering the mine tailings with 60 cm of topsoil increased the mass of Zn and Cd leached relative to no topsoil. When the subsoil was absent, Zn and Cd leaching increased by as much as 20-fold, verifying the ability of soil to act as a sink for metals. Mine tailing remediation by establishing vegetation can reduce Pb movement but may enhance short-term Cd and Zn leaching. However, the changes were relatively small and do not outweigh the benefits of using vegetation in mine tailings reclamation.« less

Nesting habitat relationships of sympatric Crested Caracaras, Red-tailed Hawks, and White-tailed Hawks in South Texas

USGS Publications Warehouse

Actkinson, M.A.; Kuvlesky, W.P.; Boal, C.W.; Brennan, L.A.; Hernandez, F.

2007-01-01

We quantified nesting-site habitats for sympatric White-tailed Hawks (Buteo albicaudatus) (n = 40), Red-tailed Hawks (B. jamaicensis) (n = 39), and Crested Caracaras (Caracara cheriway) (n = 24) in the Coastal Sand Plain of south Texas. White-tailed Hawks and Crested Caracara nest sites occurred in savannas, whereas Red-tailed Hawk nest sites occurred in woodlands on the edge of savannas. White-tailed Hawk nest sites were in shrubs and trees that were shorter (3.5 ?? 1.0 m) and had smaller canopy diameters (5.5 ?? 2.1 m) than those of Red-tailed Hawks (10.1 ?? 2.0 m, 13.7 ?? 5.8 m) and Crested Caracaras (5.6 ?? 1.7 m, 8.5 ?? 3.5 m). Red-tailed Hawk nest sites had higher woody densities (15.7 ?? 9.6 plants) and more woody cover (84 ?? 19%) than those of White-tailed Hawks (5.6 ?? 5.8 plants, 20 ?? 21%) and Crested Caracaras (9.9 ?? 6.7 plants, 55 ?? 34%). Crested Caracara nest sites were in dense, multi-branched shrubs composed of more living material (97 ?? 3%) than those of White-tailed (88 ?? 18%) and Red-tailed hawks (88 ?? 18%). Nest sites of White-tailed Hawks, Red-tailed Hawks, and Crested Caracaras were similar to random samples from the surrounding habitat indicating that preferred nesting habitat was available for each of these species at least within 60 m of active nest sites. Nest tree height, along with woody plant and native grass cover best discriminated nest sites among the three raptor species. There was no overlap at Red-tailed and White-tailed hawk nest sites in vegetation structure, while Crested Caracara nests were in habitat intermediate between the two other species. Partitioning of nesting habitat may be how these raptor species co-exist at the broader landscape scale of our study area in the Coastal Sand Plain of Texas.

Microtubule-Actin Crosslinking Factor 1 Is Required for Dendritic Arborization and Axon Outgrowth in the Developing Brain.

PubMed

Ka, Minhan; Kim, Woo-Yang

2016-11-01

Dendritic arborization and axon outgrowth are critical steps in the establishment of neural connectivity in the developing brain. Changes in the connectivity underlie cognitive dysfunction in neurodevelopmental disorders. However, molecules and associated mechanisms that play important roles in dendritic and axon outgrowth in the brain are only partially understood. Here, we show that microtubule-actin crosslinking factor 1 (MACF1) regulates dendritic arborization and axon outgrowth of developing pyramidal neurons by arranging cytoskeleton components and mediating GSK-3 signaling. MACF1 deletion using conditional mutant mice and in utero gene transfer in the developing brain markedly decreased dendritic branching of cortical and hippocampal pyramidal neurons. MACF1-deficient neurons showed reduced density and aberrant morphology of dendritic spines. Also, loss of MACF1 impaired the elongation of callosal axons in the brain. Actin and microtubule arrangement appeared abnormal in MACF1-deficient neurites. Finally, we found that GSK-3 is associated with MACF1-controlled dendritic differentiation. Our findings demonstrate a novel role for MACF1 in neurite differentiation that is critical to the creation of neuronal connectivity in the developing brain.

SAD kinases sculpt axonal arbors of sensory neurons through long- and short-term responses to neurotrophin signals.

PubMed

Lilley, Brendan N; Pan, Y Albert; Sanes, Joshua R

2013-07-10

Extrinsic cues activate intrinsic signaling mechanisms to pattern neuronal shape and connectivity. We showed previously that three cytoplasmic Ser/Thr kinases, LKB1, SAD-A, and SAD-B, control early axon-dendrite polarization in forebrain neurons. Here, we assess their role in other neuronal types. We found that all three kinases are dispensable for axon formation outside of the cortex but that SAD kinases are required for formation of central axonal arbors by subsets of sensory neurons. The requirement for SAD kinases is most prominent in NT-3 dependent neurons. SAD kinases transduce NT-3 signals in two ways through distinct pathways. First, sustained NT-3/TrkC signaling increases SAD protein levels. Second, short-duration NT-3/TrkC signals transiently activate SADs by inducing dephosphorylation of C-terminal domains, thereby allowing activating phosphorylation of the kinase domain. We propose that SAD kinases integrate long- and short-duration signals from extrinsic cues to sculpt axon arbors within the CNS. Copyright © 2013 Elsevier Inc. All rights reserved.

Tail Buffeting

NASA Technical Reports Server (NTRS)

Abdrashitov, G.

1943-01-01

An approximate theory of buffeting is here presented, based on the assumption of harmonic disturbing forces. Two cases of buffeting are considered: namely, for a tail angle of attack greater and less than the stalling angle, respectively. On the basis of the tests conducted and the results of foreign investigators, a general analysis is given of the nature of the forced vibrations the possible load limits on the tail, and the methods of elimination of buffeting.

Research on Long Tail Recommendation Algorithm

NASA Astrophysics Data System (ADS)

Hu, Xuezhi; Zhang, Chuang; Wu, Ming; Zeng, Yang

2017-10-01

Most recommendation systems in the major electronic commerce platforms are influenced by the long tail effect more or less. There are sufficient researches of how to assess recommendation effect while no criteria to evaluate long tail recommendation rate. In this study, we first discussed the existing problems of recommending long tail products through specific experiments. Then we proposed a long tail evaluation criteria and compared the performance in long tail recommendation between different models.

Action potential propagation recorded from single axonal arbors using multi-electrode arrays.

PubMed

Tovar, Kenneth R; Bridges, Daniel C; Wu, Bian; Randall, Connor; Audouard, Morgane; Jang, Jiwon; Hansma, Paul K; Kosik, Kenneth S

2018-04-11

We report the presence of co-occurring extracellular action potentials (eAPs) from cultured mouse hippocampal neurons among groups of planar electrodes on multi-electrode arrays (MEAs). The invariant sequences of eAPs among co-active electrode groups, repeated co-occurrences and short inter-electrode latencies are consistent with action potential propagation in unmyelinated axons. Repeated eAP co-detection by multiple electrodes was widespread in all our data records. Co-detection of eAPs confirms they result from the same neuron and allows these eAPs to be isolated from all other spikes independently of spike sorting algorithms. We averaged co-occurring events and revealed additional electrodes with eAPs that would otherwise be below detection threshold. We used these eAP cohorts to explore the temperature sensitivity of action potential propagation and the relationship between voltage-gated sodium channel density and propagation velocity. The sequence of eAPs among co-active electrodes 'fingerprints' neurons giving rise to these events and identifies them within neuronal ensembles. We used this property and the non-invasive nature of extracellular recording to monitor changes in excitability at multiple points in single axonal arbors simultaneously over several hours, demonstrating independence of axonal segments. Over several weeks, we recorded changes in inter-electrode propagation latencies and ongoing changes in excitability in different regions of single axonal arbors. Our work illustrates how repeated eAP co-occurrences can be used to extract physiological data from single axons with low electrode density MEAs. However, repeated eAP co-occurrences leads to over-sampling spikes from single neurons and thus can confound traditional spike-train analysis.

A study of weak anisotropy in electron pressure in the tail current sheet

NASA Technical Reports Server (NTRS)

Lee, D.-Y.; Voigt, G.-H.

1995-01-01

We adopt a magnetotail model with stretched field lines where ion motions are generally nonadiabatic and where it is assumed that the pressure anisotropy resides only in the electron pressure tensor. We show that the magnetic field lines with p(perpendicular) greater than p(parallel) are less stretched than the corresponding field lines in the isotropic model. For p(parallel) greater than p(perpendicular), the magnetic field lines become more and more stretched as the anisotropy approaches the marginal firehose limit, p(parallel) = p(perpendicular) + B(exp 2)/mu(sub 0). We also show that the tail current density is highly enhanced at the firehose limit, a situation that might be subject to a microscopic instability. However, we emphasize that the enhancement in the current density is notable only near the center of the tail current sheet (z = 0). Thus it remains unclear whether any microscopic instability can significantly alter the global magnetic field configuration of the tail. By comparing the radius of the field-line curvature at z = 0 with the particle's gyroradius, we suspect that even the conventional adiabatic description of electrons may become questionable very close to the marginal firehose limit.

Alanine substitution of conserved residues in the cytoplasmic tail of herpes simplex virus gB can enhance or abolish cell fusion activity and viral entry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruel, Nancy; Zago, Anna; Spear, Patricia G.

2006-03-01

Herpes simplex virus (HSV) glycoprotein B (gB) is one of the four viral glycoproteins required for viral entry and cell fusion and is highly conserved among herpesviruses. Mutants of HSV type 2 gB were generated by substituting conserved residues in the cytoplasmic tail with alanine or by deleting 41 amino acids from the C-terminus. Some of the mutations abolished cell fusion activity and also prevented transport of gB to the cell surface, identifying residues in the gB cytoplasmic tail that are critical for intracellular transport of this glycoprotein. These mutations also prevented production of infectious virus, possibly because the mutantmore » forms of gB were not transported to the site of envelopment. Other mutations, particularly the deletion, significantly enhanced cell fusion activity. These mutations, as well as others described previously, identify regions of the gB cytoplasmic domain that modulate cell fusion activity.« less

Aerodynamics of a Flapping Airfoil with a Flexible Tail

NASA Astrophysics Data System (ADS)

Lai, Alan Kai San

This dissertation presents computational solutions to an airfoil in a oscillatory heaving motion with a aeroelastically flexible tail attachment. An unsteady potential flow solver is coupled to a structural solver to obtain the aeroelastic flow solution over an inviscid fluid to investigate the propulsive performance of such a configuration. The simulation is then extended to a two-dimensional viscous solver by coupling NASA's CFL3D solver to the structural solver to study how the flow is altered by the presence of viscosity. Finally, additional simulations are done in three dimensions over wings with varying aspect ratio to study the three-dimensional effects on the propulsive performance of an airfoil with an aeroelastic tail. The computation reveals that the addition of the aeroelastic trailing edge improved the thrust generated by a heaving airfoil significantly. As the frequency of the heaving motion increases, the thrust generated by the airfoil with the tail increases exponentially. In an inviscid fluid, the increase in thrust is insufficient to overcome the increase in power required to maintain the motion and as a result the overall propulsive efficiency is reduced. When the airfoil is heaving in a viscous fluid, the presence of a suction boundary layer and the appearance of leading edge vortex increase the thrust generated to such an extent that the propulsive efficiency is increased by about 3% when compared to the same airfoil with a rigid tail. The three-dimensional computations shows that the presence of the tip vorticies suppress some of the increase in thrust observed in the two-dimensional viscous computations for short span wings. For large span wings, the overall thrust enhancing capabilities of the aeroelastic tail is preserved.

Runaway tails in magnetized plasmas

NASA Technical Reports Server (NTRS)

Moghaddam-Taaheri, E.; Vlahos, L.; Rowland, H. L.; Papadopoulos, K.

1985-01-01

The evolution of a runaway tail driven by a dc electric field in a magnetized plasma is analyzed. Depending on the strength of the electric field and the ratio of plasma to gyrofrequency, there are three different regimes in the evolution of the tail. The tail can be (1) stable with electrons accelerated to large parallel velocities, (2) unstable to Cerenkov resonance because of the depletion of the bulk and the formation of a positive slope, (3) unstable to the anomalous Doppler resonance instability driven by the large velocity anisotropy in the tail. Once an instability is triggered (Cerenkov or anomalous Doppler resonance) the tail relaxes into an isotropic distribution. The role of a convection type loss term is also discussed.

Tail Rotor Airfoils Stabilize Helicopters, Reduce Noise

NASA Technical Reports Server (NTRS)

2010-01-01

Founded by former Ames Research Center engineer Jim Van Horn, Van Horn Aviation of Tempe, Arizona, built upon a Langley Research Center airfoil design to create a high performance aftermarket tail rotor for the popular Bell 206 helicopter. The highly durable rotor has a lifetime twice that of the original equipment manufacturer blade, reduces noise by 40 percent, and displays enhanced performance at high altitudes. These improvements benefit helicopter performance for law enforcement, military training, wildfire and pipeline patrols, and emergency medical services.

Evaluation Of The Advanced Operating System Of The Ann Arbor Transportation Authority : Driver And Dispatcher Perceptions Of AATA'S Advanced Operating System

DOT National Transportation Integrated Search

1999-01-01

In 1997, the Ann Arbor (Michigan) Transportation Authority began deploying advanced public transportation systems (APTS) technologies in its fixed route and paratransit operations. The project's concept is the integration of a range of such technolog...

Dwarf Galaxies Swimming in Tidal Tails

NASA Technical Reports Server (NTRS)

2005-01-01

This false-color infrared image from NASA's Spitzer Space Telescope shows little 'dwarf galaxies' forming in the 'tails' of two larger galaxies that are colliding together. The big galaxies are at the center of the picture, while the dwarfs can be seen as red dots in the red streamers, or tidal tails. The two blue dots above the big galaxies are stars in the foreground.

Galaxy mergers are common occurrences in the universe; for example, our own Milky Way galaxy will eventually smash into the nearby Andromeda galaxy. When two galaxies meet, they tend to rip each other apart, leaving a trail, called a tidal tail, of gas and dust in their wake. It is out of this galactic debris that new dwarf galaxies are born.

The new Spitzer picture demonstrates that these particular dwarfs are actively forming stars. The red color indicates the presence of dust produced in star-forming regions, including organic molecules called polycyclic aromatic hydrocarbons. These carbon-containing molecules are also found on Earth, in car exhaust and on burnt toast, among other places. Here, the molecules are being heated up by the young stars, and, as a result, shine in infrared light.

This image was taken by the infrared array camera on Spitzer. It is a 4-color composite of infrared light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8.0 microns (red). Starlight has been subtracted from the orange and red channels in order to enhance the dust features.

Why are there more arboreal ant species in primary than in secondary tropical forests?

PubMed

Klimes, Petr; Idigel, Cliffson; Rimandai, Maling; Fayle, Tom M; Janda, Milan; Weiblen, George D; Novotny, Vojtech

2012-09-01

1. Species diversity of arboreal arthropods tends to increase during rainforest succession so that primary forest communities comprise more species than those from secondary vegetation, but it is not well understood why. Primary forests differ from secondary forests in a wide array of factors whose relative impacts on arthropod diversity have not yet been quantified. 2. We assessed the effects of succession-related determinants on a keystone ecological group, arboreal ants, by conducting a complete census of 1332 ant nests from all trees with diameter at breast height ≥ 5 cm occurring within two (unreplicated) 0·32-ha plots, one in primary and one in secondary lowland forest in New Guinea. Specifically, we used a novel rarefaction-based approach to match number, size distribution and taxonomic structure of trees in primary forest communities to those in secondary forest and compared the resulting numbers of ant species. 3. In total, we recorded 80 nesting ant species from 389 trees in primary forest but only 42 species from 295 trees in secondary forest. The two habitats did not differ in the mean number of ant species per tree or in the relationship between ant diversity and tree size. However, the between-tree similarity of ant communities was higher in secondary forest than in primary forest, as was the between-tree nest site similarity, suggesting that secondary trees were more uniform in providing nesting microhabitats. 4. Using our rarefaction method, the difference in ant species richness between two forest types was partitioned according to the effects of higher tree density (22·6%), larger tree size (15·5%) and higher taxonomic diversity of trees (14·3%) in primary than in secondary forest. The remaining difference (47·6%) was because of higher beta diversity of ant communities between primary forest trees. In contrast, difference in nest density was explained solely by difference in tree density. 5. Our study shows that reduction in plant taxonomic

The new idea of transporting tailings-logs in tailings slurry pipeline and the innovation of technology of mining waste-fill method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin Yu; Wang Fuji; Tao Yan

2000-07-01

This paper introduced a new idea of transporting mine tailings-logs in mine tailings-slurry pipeline and a new technology of mine cemented filing of tailings-logs with tailings-slurry. The hydraulic principles, the compaction of tailings-logs and the mechanic function of fillbody of tailings-logs cemented by tailings-slurry have been discussed.

Numerical study on the power extraction performance of a flapping foil with a flexible tail

NASA Astrophysics Data System (ADS)

Wu, J.; Shu, C.; Zhao, N.; Tian, F.-B.

2015-01-01

The numerical study on the power extraction performance of a flapping foil with a flexible tail is performed in this work. A NACA0015 airfoil is arranged in a two-dimensional laminar flow and imposed with a synchronous harmonic plunge and pitch rotary motion. A flat plate that is attached to the trailing edge of the foil is utilized to model a tail, and so they are viewed as a whole for the purpose of power extraction. In addition, the tail either is rigid or can deform due to the exerted hydrodynamic forces. To implement numerical simulations, an immersed boundary-lattice Boltzmann method is employed. At a Reynolds number of 1100 and the position of the pitching axis at third chord, the influences of the mass and flexibility of the tail as well as the frequency of motion on the power extraction are systematically examined. It is found that compared to the foil with a rigid tail, the efficiency of power extraction for the foil with a deformable tail can be improved. Based on the numerical analysis, it is indicated that the enhanced plunging component of the power extraction, which is caused by the increased lift force, directly contributes to the efficiency improvement. Since a flexible tail with medium and high masses is not beneficial to the efficiency improvement, a flexible tail with low mass together with high flexibility is recommended in the flapping foil based power extraction system.

Arboreal nesting as anti-predator adaptation by savanna chimpanzees (Pan troglodytes verus) in southeastern Senegal.

PubMed

Pruetz, J D; Fulton, S J; Marchant, L F; McGrew, W C; Schiel, M; Waller, M

2008-04-01

Chimpanzees (Pan troglodytes) make nests for resting and sleeping, which is unusual for anthropoid primates but common to all great apes. Arboreal nesting has been linked to predation pressure, but few studies have tested the adaptive nature of this behavior. We collected data at two chimpanzee study sites in southeastern Senegal that differed in predator presence to test the hypothesis that elevated sleeping platforms are adaptations for predator defense. At Assirik in the Parc National du Niokolo-Koba, chimpanzees face four species of large carnivore, whereas at Fongoli, outside national park boundaries, humans have exterminated almost all natural predators. We quantified the availability of vegetation at the two sites to test the alternative hypothesis that differences in nesting reflect differences in habitat structure. We also examined possible sex differences in nesting behavior, community demographic differences, seasonality and nest age differences as variables also potentially affecting nest characteristics and nesting behavior between the two sites. Chimpanzees at Fongoli nested at lower heights and farther apart than did chimpanzees at Assirik and sometimes made nests on the ground. The absence of predators outside of the national park may account for the differences in nest characteristics at the two sites, given the similarities in habitat structure between Fongoli and Assirik. However, Fongoli chimpanzees regularly build arboreal nests for sleeping, even under minimal predation pressure, and this requires explanation.

Microtubule-Actin Crosslinking Factor 1 is required for dendritic arborization and axon outgrowth in the developing brain

PubMed Central

Ka, Minhan; Kim, Woo-Yang

2015-01-01

Dendritic arborization and axon outgrowth are critical steps in the establishment of neural connectivity in the developing brain. Changes in the connectivity underlie cognitive dysfunction in neurodevelopmental disorders. However, molecules and associated mechanisms that play important roles in dendritic and axon outgrowth in the brain are only partially understood. Here, we show that Microtubule-Actin Crosslinking Factor 1 (MACF1) regulates dendritic arborization and axon outgrowth of developing pyramidal neurons by arranging cytoskeleton components and mediating GSK-3 signaling. MACF1 deletion using conditional mutant mice and in utero gene transfer in the developing brain markedly decreased dendritic branching of cortical and hippocampal pyramidal neurons. MACF1-deficient neurons showed reduced density and aberrant morphology of dendritic spines. Also, loss of MACF1 impaired the elongation of callosal axons in the brain. Actin and microtubule arrangement appeared abnormal in MACF1-deficient neurites. Finally, we found that GSK-3 is associated with MACF1-controlled dendritic differentiation. Our findings demonstrate a novel role for MACF1 in neurite differentiation that is critical to the creation of neuronal connectivity in the developing brain. PMID:26526844

Spizaetus hawk-eagles as predators of arboreal colobines.

PubMed

Fam, S D; Nijman, V

2011-04-01

The predation pressure put on primates by diurnal birds of prey differs greatly between continents. Africa and South America have specialist raptors (e.g. crowned hawk-eagle Stephanoaetus coronatus and harpy eagle Harpia harpyja) whereas in Asia the only such specialist's (Philippine eagle Pithecophaga jefferyi) distribution is largely allopatric with primates. The almost universal absence of polyspecific groups in Asia (common in Africa and South America) may indicate reduced predation pressure. As such there is almost no information on predation pressures on primates in Asia by raptors. Here we report successful predation of a juvenile banded langur Presbytis femoralis (~2 kg) by a changeable hawk-eagle Spizaetus cirrhatus. The troop that was attacked displayed no signs of being alarmed, and no calls were made before the event. We argue that in insular Southeast Asia, especially, large Spizaetus hawk-eagles (~2 kg) are significant predators of arboreal colobines. Using data on the relative size of sympatric Spizaetus hawk-eagles and colobines we make predictions on where geographically we can expect the highest predation pressure (Thai-Malay Peninsula) and which colobines are least (Nasalis larvatus, Trachypithecus auratus, P. thomasi) and most (P. femoralis, T. cristatus) affected.

Exploring Mercury Tail

NASA Image and Video Library

2008-08-26

As the MESSENGER spacecraft approached Mercury, the UVVS field of view was scanned across the planet's exospheric "tail," which is produced by the solar wind pushing Mercury's exosphere (the planet's extremely thin atmosphere) outward. This figure, recently published in Science magazine, shows a map of the distribution of sodium atoms as they stream away from the planet (see PIA10396); red and yellow colors represent a higher abundance of sodium than darker shades of blue and purple, as shown in the colored scale bar, which gives the brightness intensity in units of kiloRayleighs. The escaping atoms eventually form a comet-like tail that extends in the direction opposite that of the Sun for many planetary radii. The small squares outlined in black correspond to individual measurements that were used to create the full map. These measurements are the highest-spatial-resolution observations ever made of Mercury's tail. In less than six weeks, on October 6, 2008, similar measurements will be made during MESSENGER's second flyby of Mercury. Comparing the measurements from the two flybys will provide an unprecedented look at how Mercury's dynamic exosphere and tail vary with time. Date Acquired: January 14, 2008. http://photojournal.jpl.nasa.gov/catalog/PIA11076

Tail-scope: Using friends to estimate heavy tails of degree distributions in large-scale complex networks

NASA Astrophysics Data System (ADS)

Eom, Young-Ho; Jo, Hang-Hyun

2015-05-01

Many complex networks in natural and social phenomena have often been characterized by heavy-tailed degree distributions. However, due to rapidly growing size of network data and concerns on privacy issues about using these data, it becomes more difficult to analyze complete data sets. Thus, it is crucial to devise effective and efficient estimation methods for heavy tails of degree distributions in large-scale networks only using local information of a small fraction of sampled nodes. Here we propose a tail-scope method based on local observational bias of the friendship paradox. We show that the tail-scope method outperforms the uniform node sampling for estimating heavy tails of degree distributions, while the opposite tendency is observed in the range of small degrees. In order to take advantages of both sampling methods, we devise the hybrid method that successfully recovers the whole range of degree distributions. Our tail-scope method shows how structural heterogeneities of large-scale complex networks can be used to effectively reveal the network structure only with limited local information.

Sleeping site ecology, but not sex, affect ecto- and hemoparasite risk, in sympatric, arboreal primates (Avahi occidentalis and Lepilemur edwardsi).

PubMed

Hokan, May; Strube, Christina; Radespiel, Ute; Zimmermann, Elke

2017-01-01

A central question in evolutionary parasitology is to what extent ecology impacts patterns of parasitism in wild host populations. In this study, we aim to disentangle factors influencing the risk of parasite exposure by exploring the impact of sleeping site ecology on infection with ectoparasites and vector-borne hemoparasites in two sympatric primates endemic to Madagascar. Both species live in the same dry deciduous forest of northwestern Madagascar and cope with the same climatic constraints, they are arboreal, nocturnal, cat-sized and pair-living but differ prominently in sleeping site ecology. The Western woolly lemur ( Avahi occidentalis ) sleeps on open branches and frequently changes sleeping sites, whereas the Milne-Edward's sportive lemur ( Lepilemur edwardsi ) uses tree holes, displaying strong sleeping site fidelity. Sleeping in tree holes should confer protection from mosquito-borne hemoparasites, but should enhance the risk for ectoparasite infestation with mites and nest-adapted ticks. Sex may affect parasite risk in both species comparably, with males bearing a higher risk than females due to an immunosuppressive effect of higher testosterone levels in males or to sex-specific behavior. To explore these hypotheses, ectoparasites and blood samples were collected from 22 individuals of A. occidentalis and 26 individuals of L. edwardsi during the dry and rainy season. L. edwardsi, but not A. occidentalis , harbored ectoparasites, namely ticks ( Haemaphysalis lemuris [Ixodidae], Ornithodoros sp. [Argasidae]) and mites ( Aetholaelaps trilyssa , [Laelapidae]), suggesting that sleeping in tree holes promotes infestation with ectoparasites. Interestingly, ectoparasites were found solely in the hot, rainy season with a prevalence of 75% ( N  = 16 animals). Blood smears were screened for the presence and infection intensity of hemoparasites. Microfilariae were detected in both species. Morphological characteristics suggested that each lemur species

Does climate have heavy tails?

NASA Astrophysics Data System (ADS)

Bermejo, Miguel; Mudelsee, Manfred

2013-04-01

When we speak about a distribution with heavy tails, we are referring to the probability of the existence of extreme values will be relatively large. Several heavy-tail models are constructed from Poisson processes, which are the most tractable models. Among such processes, one of the most important are the Lévy processes, which are those process with independent, stationary increments and stochastic continuity. If the random component of a climate process that generates the data exhibits a heavy-tail distribution, and if that fact is ignored by assuming a finite-variance distribution, then there would be serious consequences (in the form, e.g., of bias) for the analysis of extreme values. Yet, it appears that it is an open question to what extent and degree climate data exhibit heavy-tail phenomena. We present a study about the statistical inference in the presence of heavy-tail distribution. In particular, we explore (1) the estimation of tail index of the marginal distribution using several estimation techniques (e.g., Hill estimator, Pickands estimator) and (2) the power of hypothesis tests. The performance of the different methods are compared using artificial time-series by means of Monte Carlo experiments. We systematically apply the heavy tail inference to observed climate data, in particular we focus on time series data. We study several proxy and directly observed climate variables from the instrumental period, the Holocene and the Pleistocene. This work receives financial support from the European Commission (Marie Curie Initial Training Network LINC, No. 289447, within the 7th Framework Programme).

Bioprocessing-Based Approach for Bitumen/Water/Fines Separation and Hydrocarbon Recovery from Oil Sands Tailings

DOE PAGES

Brigmon, Robin L.; Berry, Christopher J.; Wade, Arielle; ...

2016-05-04

Oil sands are a major source of oil, but their industrial processing generates tailings ponds that are an environmental hazard. The main concerns are mature fine tailings (MFT) composed of residual hydrocarbons, water, and fine clay. Tailings ponds include toxic contaminants such as heavy metals, and toxic organics including naphthenics. Naphthenic acids and polyaromatic hydrocarbons (PAHs) degrade very slowly and pose a long-term threat to surface and groundwater, as they can be transported in the MFT. Research into improved technologies that would enable densification and settling of the suspended particles is ongoing. In batch tests, BioTiger™, a microbial consortium thatmore » can metabolize PAHs, demonstrated improved oil sands tailings settling from a Canadian tailings pond. Results also showed, depending on the timing of the measurements, lower suspended solids and turbidity. Elevated total organic carbon was observed in the first 48 hours in the BioTiger™-treated columns and then decreased in overlying water. Oil sands tailings mixed with BioTiger™ showed a two-fold reduction in suspended solids within 24 hours as compared to abiotic controls. The tailings treated with BioTiger™ increased in microbial densities three orders of magnitude from 8.5 × 105 CFU/mL to 1.2 × 108 CFU/mL without any other carbon or energy source added, indicating metabolism of hydrocarbons and other available nutrients. Results demonstrated that bioaugmentation of BioTiger™ increased separation of organic carbon from particles in oil sands and enhanced settling with tailings with improved water quality.« less

Distinct Dendritic Arborization and In Vivo Firing Patterns of Parvalbumin-Expressing Basket Cells in the Hippocampal Area CA3

PubMed Central

Tukker, John J.; Lasztóczi, Bálint; Katona, Linda; Roberts, J. David B.; Pissadaki, Eleftheria K.; Dalezios, Yannis; Márton, László; Zhang, Limei; Klausberger, Thomas; Somogyi, Peter

2015-01-01

Hippocampal CA3 area generates temporally structured network activity such as sharp waves and gamma and theta oscillations. Parvalbumin-expressing basket cells, making GABAergic synapses onto cell bodies and proximal dendrites of pyramidal cells, control pyramidal cell activity and participate in network oscillations in slice preparations, but their roles in vivo remain to be tested. We have recorded the spike timing of parvalbumin-expressing basket cells in areas CA2/3 of anesthetized rats in relation to CA3 putative pyramidal cell firing and activity locally and in area CA1. During theta oscillations, CA2/3 basket cells fired on the same phase as putative pyramidal cells, but, surprisingly, significantly later than downstream CA1 basket cells. This indicates a distinct modulation of CA3 and CA1 pyramidal cells by basket cells, which receive different inputs. We observed unexpectedly large dendritic arborization of CA2/3 basket cells in stratum lacunosum moleculare (33% of length, 29% surface, and 24% synaptic input from a total of ~35,000), different from the dendritic arborizations of CA1 basket cells. Area CA2/3 basket cells fired phase locked to both CA2/3 and CA1 gamma oscillations, and increased firing during CA1 sharp waves, thus supporting the role of CA3 networks in the generation of gamma oscillations and sharp waves. However, during ripples associated with sharp waves, firing of CA2/3 basket cells was phase locked only to local but not CA1 ripples, suggesting the independent generation of fast oscillations by basket cells in CA1 and CA2/3. The distinct spike timing of basket cells during oscillations in CA1 and CA2/3 suggests differences in synaptic inputs paralleled by differences in dendritic arborizations. PMID:23595740

The Tail of BPM

NASA Astrophysics Data System (ADS)

Kruba, Steve; Meyer, Jim

Business process management suites (BPMS's) represent one of the fastest growing segments in the software industry as organizations automate their key business processes. As this market matures, it is interesting to compare it to Chris Anderson's 'Long Tail.' Although the 2004 "Long Tail" article in Wired magazine was primarily about the media and entertainment industries, it has since been applied (and perhaps misapplied) to other markets. Analysts describe a "Tail of BPM" market that is, perhaps, several times larger than the traditional BPMS product market. This paper will draw comparisons between the concepts in Anderson's article (and subsequent book) and the BPM solutions market.

Potential effects of arboreal and terrestrial avian dispersers on seed dormancy, seed germination and seedling establishment in Ormosia (Papilionoideae) species in Peru

USGS Publications Warehouse

Foster, Mercedes S.

2008-01-01

The relative effectiveness of arboreal or terrestrial birds at dispersing seeds of Ormosia macrocalyx and O. bopiensis (Fabaceae: Papilionoideae) were studied in south-eastern Peru. Seeds of both species were either scarified, to represent seed condition after dispersal by terrestrial birds, or left intact, to represent seed condition after dispersal by arboreal birds. Seeds were distributed along forest transects, and germination, seedling development and mortality were monitored to determine the successes of the two groups at producing seedlings. Scarified seeds germinated with the early rains of the dry-to-wet-season transition, when erratic rainfall was interspersed with long dry spells. Intact seeds germinated 30 d later when the rain was more plentiful and regular. Intact seeds of O. macrocalyx gave rise to significantly more seedlings (41.1% vs. 25.5%) than did scarified seeds, in part, because significantly more seedlings from scarified seeds (n = 20) than from intact seeds (n = 3) died from desiccation when their radicles failed to enter the dry ground present during the dry-to-wet-season transition. Also, seedlings from scarified seeds were neither larger nor more robust than those from intact seeds despite their longer growing period. Results are consistent with the hypothesis that dispersal effectiveness of arboreal birds, at least for O. macrocalyx, is greater than that of terrestrial birds. Screen-house experiments in which seedlings developed under different watering regimes supported this result. Numbers of seedlings developing from intact and scarified seeds of O. bopiensis did not differ significantly.

Fluorescence enhancement of fluorescent unnatural streptavidin by binding of a biotin analogue with spacer tail and its application to biotin sensing.

PubMed

Zhu, Xianwei; Shinohara, Hiroaki

2014-01-01

We designed a novel molecular biosensing system for the detection of biotin, an important vitamin by the combination of fluorescent unnatural streptavidin with a commercialized biotin-(AC5)2-hydrazide. A fluorescent unnatural amino acid, BODIPY-FL-aminophenylalanine (BFLAF), was position-specifically incorporated into Trp120 of streptavidin by four-base codon method. Fluorescence of the Trp120BFLAF mutant streptavidin was enhanced by the addition of biotin-(AC5)2-hydrazide with the concentration dependent, whereas fluorescence enhancement was not observed at all by the addition of natural biotin. It was considered that the spacer tail of biotin-(AC5)2-hydrazide may disturb the fluorescence quenching of the Trp120BFLAF by Trp79 and Trp108 of the neighbor subunit. Therefore, biotin sensing was carried out by the competitive binding reaction of biotin-(AC5)2-hydrazide and natural biotin to the fluorescent mutant streptavidin. The fluorescence intensity decreased by increasing free biotin concentration. The result suggested that molecular biosensor for small ligand could be successfully designed by the pair of fluorescent mutant binding protein and ligand analogue.

Parametric Study of Synthetic-Jet-Based Flow Control on a Vertical Tail Model

NASA Astrophysics Data System (ADS)

Monastero, Marianne; Lindstrom, Annika; Beyar, Michael; Amitay, Michael

2015-11-01

Separation control over the rudder of the vertical tail of a commercial airplane using synthetic-jet-based flow control can lead to a reduction in tail size, with an associated decrease in drag and increase in fuel savings. A parametric, experimental study was undertaken using an array of finite span synthetic jets to investigate the sensitivity of the enhanced vertical tail side force to jet parameters, such as jet spanwise spacing and jet momentum coefficient. A generic wind tunnel model was designed and fabricated to fundamentally study the effects of the jet parameters at varying rudder deflection and model sideslip angles. Wind tunnel results obtained from pressure measurements and tuft flow visualization in the Rensselaer Polytechnic Subsonic Wind Tunnel show a decrease in separation severity and increase in model performance in comparison to the baseline, non-actuated case. The sensitivity to various parameters will be presented.

Utilisation of joint movement range in arboreal primates compared with human subjects: an evolutionary frame for primary osteoarthritis.

PubMed Central

Alexander, C J

1994-01-01

OBJECTIVE--To determine whether an arboreal lifestyle required full use of movement ranges underutilised in nine joint groups in humans, because under-utilisation of available movement range may be associated with susceptibility to primary osteoarthritis. METHODS--Utilisation of the nine joint groups was studied in two species of primate exercising in a simulated arboreal environment, using 'focal animal' observation techniques supplemented by telephoto photography and by review of archival material from other sources. Fifteen apes were observed over a total observation period of 20.2 man-hours and 152 films were analysed for utilisation of movement range. RESULTS--With one exception, all the movement ranges reported to be under-utilised in humans were fully utilised by the apes in climbing activities. The exception, metacarpophalangeal extension, was an essential component of the chimpanzee ground progression mode of knuckle walking. CONCLUSIONS--The underused movement range in several human joints is explicable as residual capacity from a semiarboreal lifestyle. If the correlation with primary osteoarthritis is confirmed, it suggests that the disease may reflect a disparity between inherited capacity and current need. The significance of the result lies in its implication that primary osteoarthritis may be preventable. Images PMID:7826133

Utilisation of joint movement range in arboreal primates compared with human subjects: an evolutionary frame for primary osteoarthritis.

PubMed

Alexander, C J

1994-11-01

To determine whether an arboreal lifestyle required full use of movement ranges underutilised in nine joint groups in humans, because under-utilisation of available movement range may be associated with susceptibility to primary osteoarthritis. Utilisation of the nine joint groups was studied in two species of primate exercising in a simulated arboreal environment, using 'focal animal' observation techniques supplemented by telephoto photography and by review of archival material from other sources. Fifteen apes were observed over a total observation period of 20.2 man-hours and 152 films were analysed for utilisation of movement range. With one exception, all the movement ranges reported to be under-utilised in humans were fully utilised by the apes in climbing activities. The exception, metacarpophalangeal extension, was an essential component of the chimpanzee ground progression mode of knuckle walking. The underused movement range in several human joints is explicable as residual capacity from a semiarboreal lifestyle. If the correlation with primary osteoarthritis is confirmed, it suggests that the disease may reflect a disparity between inherited capacity and current need. The significance of the result lies in its implication that primary osteoarthritis may be preventable.

Bovine Viral Diarrhea Virus (BVDV) in White-Tailed Deer (Odocoileus virginianus)

PubMed Central

Passler, Thomas; Ditchkoff, Stephen S.; Walz, Paul H.

2016-01-01

Bovine viral diarrhea virus (BVDV) is the prototypic member of the genus Pestivirus in the family Flaviviridae. Infections with BVDV cause substantial economic losses to the cattle industries, prompting various organized control programs in several countries. In North America, these control programs are focused on the identification and removal of persistently infected (PI) cattle, enhancement of BVDV-specific immunity through vaccination, and the implementation of biosecure farming practices. To be successful, control measures must be based on complete knowledge of the epidemiology of BVDV, including the recognition of other potential sources of the virus. BVDV does not possess strict host-specificity, and infections of over 50 species in the mammalian order Artiodactyla have been reported. Over 50 years ago, serologic surveys first suggested the susceptibility of white-tailed deer (Odocoileus virginianus), the most abundant free-ranging ruminant in North America, to BVDV. However, susceptibility of white-tailed deer to BVDV infection does not alone imply a role in the epidemiology of the virus. To be a potential wildlife reservoir, white-tailed deer must: (1) be susceptible to BVDV, (2) shed BVDV, (3) maintain BVDV in the population, and (4) have sufficient contact with cattle that allow spillback infections. Based on the current literature, this review discusses the potential of white-tailed deer to be a reservoir for BVDV. PMID:27379074

Biosynthesis of Astrocytic Trehalose Regulates Neuronal Arborization in Hippocampal Neurons.

PubMed

Martano, Giuseppe; Gerosa, Laura; Prada, Ilaria; Garrone, Giulia; Krogh, Vittorio; Verderio, Claudia; Passafaro, Maria

2017-09-20

Trehalose is a nonreducing disaccharide that has recently attracted much attention because of its ability to inhibit protein aggregation, induce autophagy, and protect against dissections and strokes. In vertebrates, the biosynthesis of trehalose was long considered absent due to the lack of annotated genes involved in this process. In contrast, trehalase (TreH), which is an enzyme required for the cleavage of trehalose, is known to be conserved and expressed. Here, we show that trehalose is present as an endogenous metabolite in the rodent hippocampus. We found that primary astrocytes were able to synthesize trehalose and release it into the extracellular space. Notably, the TreH enzyme was observed only in the soma of neurons, which are the exclusive users of this substrate. A statistical analysis of the metabolome during different stages of maturation indicated that this metabolite is implicated in neuronal maturation. A morphological analysis of primary neurons confirmed that trehalose is required for neuronal arborization.

Meeting report for Odd Pols 2016: Ann Arbor 2.0.

PubMed

Roy-Engel, Astrid M

2017-05-15

The Tenth International Conference on Transcription by RNA Polymerases I, III, IV and V (the 'Odd Pols') was held June 24-28, 2016 at the University of Michigan, Ann Arbor, USA and organized by David Engelke, Deborah Johnson, Richard Maraia, Lawrence Rothblum, David Schneider, Andrzej Wierzbicki and Astrid Engel. The organizers are grateful for the support from the Rackham Graduate School of the University of Michigan for providing the meeting venue. The environment provided a great background with unexpected encounters with fireflies, free live music and a festive fireworks display. The meeting was composed of eleven oral sessions and a poster session. The keynote speaker, Dave Engelke, opened the meeting with his presentation entitled "A personal history of pol III transcription - how we got here from the 'good old days'." The meeting drew attendees from sixteen countries that shared their research discoveries. Here we present some of the highlights from the meeting using summaries provided by the participants. Copyright © 2016 Elsevier B.V. All rights reserved.

Metal removal from oil sands tailings pond water by indigenous micro-alga.

PubMed

Mahdavi, Hamed; Ulrich, Ania C; Liu, Yang

2012-09-01

This paper reports the removal of ten target metals of environmental concern ((53)Cr, Mn, Co, (60)Ni, (65)Cu, (66)Zn, As, (88)Sr, (95)Mo, and Ba) from oil sands tailings pond water. The organism responsible for removal was found to be an indigenous green micro-alga identified as Parachlorella kessleri by sequencing of the 23S rRNA gene. P. kessleri grew in tailings pond water samples taken from two oil sands operators (Syncrude Canada Ltd. and Albian Sands Energy Inc.), and enriched with low (0.24 mM NO(3)(-) and 0.016 mM PO(4)(-3)) and high (1.98 mM NO(3)(-) and 0.20mM PO(4)(-3)) concentrations of nutrient supplements (the most realistic scenario). The removal of (60)Ni, (65)Cu, As, (88)Sr, (95)Mo, and Ba from Syncrude tailings pond water was significantly enhanced by high concentrations of nitrogen and phosphorus, whereas the high nutrient concentrations adversely affected the removal of Co, (60)Ni, As, (88)Sr, and Mo in samples of Albian tailings pond water. Based on ANOVA two-factor analysis, higher nutrient concentration does not always result in higher metal removal, and TPW source must also be considered. Copyright © 2012. Published by Elsevier Ltd.

Comparison of the breeding biology of sympatric red-tailed Hawks, White-tailed Hawks, and Crested Caracaras in south Texas

USGS Publications Warehouse

Actkinson, M.A.; Kuvlesky, W.P.; Boal, C.W.; Brennan, L.A.; Hernandez, F.

2009-01-01

We compared the breeding biology of sympatric nesting Red-tailed Hawks (Buteo jamaicensis), White-tailed Hawks (Buteo albicaudatus), and Crested Caracaras (Caracara cheriway) in south Texas during 2003 and 2004. We monitored 46 breeding attempts by Red-tailed Hawks, 56 by White-tailed Hawks, and 27 by Crested Caracaras. Observed nesting success was similar for Red-tailed Hawks (62%) and Crested Caracaras (61%), but lower for White-tailed Hawks (51%). Daily survival rates (0.99) were the same for all three species. Red-tailed Hawks and White-tailed Hawks both fledged 1.13 young per nesting pair and Crested Caracaras fledged 1.39 young per nesting pair. All three species nested earlier in 2004 than in 2003; in addition, the overall nesting density of these three species almost doubled from 2003 (1.45 pairs/km2) to 2004 (2.71 pairs/km2). Estimated productivity of all three species was within the ranges reported from other studies. Given extensive and progressive habitat alteration in some areas of south Texas, and the limited distributions of White-tailed Hawks and Crested Caracaras, the presence of large ranches managed for free-range cattle production and hunting leases likely provides important habitat and may be key areas for conservation of these two species. ?? 2009 The Raptor Research Foundation, Inc.

The behavioral responses of amphibians and reptiles to microgravity on parabolic flights.

PubMed

Wassersug, Richard J; Roberts, Lesley; Gimian, Jenny; Hughes, Elizabeth; Saunders, Ryan; Devison, Darren; Woodbury, Jonathan; O'Reilly, James C

2005-01-01

In the present study, we exposed 53 animals from 23 different species of amphibians and reptiles to microgravity (mug). This nearly doubles the number of amphibians and reptiles observed so far in mug. The animals were flown on a parabolic flight, which provided 20-25s of mug, to better characterize behavioral reactions to abrupt exposure to mug. Highly fossorial limbless caecilians and amphisbaenians showed relatively limited movement in mug. Limbed quadrupedal reptiles that were non-arboreal in the genera Leiocephalus, Anolis, and Scincella showed the typical righting response and enormous amounts of body motion and tail rotation, which we interpreted as both righting responses and futile actions to grasp the substrate. Both arboreal and non-arboreal geckos in the genera Uroplatus, Palmatogecko, Stenodactylus, Tarentola, and Eublepharis instead showed a skydiving posture previously reported for highly arboreal anurans. Some snakes, in the genera Thamnophis and Elaphe, which typically thrashed and rolled in mug, managed to knot their own bodies with their tails and immediately became quiescent. This suggests that these reptiles gave stable physical contact, which would indicate that they were not falling, primacy over vestibular input that indicated that they were in freefall. The fact that they became quiet upon self-embrace further suggests a failure to distinguish self from non-self. The patterns of behavior seen in amphibians and reptiles in mug can be explained in light of their normal ecology and taxonomic relations.

Ecotoxicity of Mine Tailings: Unrehabilitated Versus Rehabilitated.

PubMed

Maboeta, M S; Oladipo, O G; Botha, S M

2018-05-01

Earthworms are bioindicators of soil pollution. The ecotoxicity of tailings from selected gold mines in South Africa was investigated utilizing Eisenia andrei bioassays and biomarkers. Samples were obtained from unrehabilitated, rehabilitated and naturally vegetated sites. Biomass, neutral red retention time (NRRT), survival and reproduction were assessed using standardized protocols. Earthworm biomass, NRRT and reproductive success in rehabilitated tailings (comparable to naturally vegetated site) were significantly higher (p < 0.05) than in unrehabilitated tailings. In addition, significantly lower (p < 0.05) body tissue concentrations of As, Cd, Co, Cu and Ni contents were found in the rehabilitated tailings compared to the unrehabilitated. Further, significantly lower (p < 0.05) soil Mn and Zn concentrations were obtained in unrehabilitated tailings than the rehabilitated and naturally vegetated sites. Overall, reduced ecotoxicity effects were confirmed in rehabilitated compared to unrehabilitated tailings. This suggests that rehabilitation as a post-mining restorative strategy has strong positive influence on mine tailings.

"Comet tail sign": A pitfall of post-gadolinium magnetic resonance imaging findings for metastatic brain tumors.

PubMed

Mitsuya, Koichi; Nakasu, Yoko; Narita, Yoshitaka; Nakasu, Satoshi; Ohno, Makoto; Miyakita, Yasuji; Abe, Masato; Ito, Ichiro; Hayashi, Nakamasa; Endo, Masahiro

2016-05-01

A highly enhanced cap attached to the surface of metastatic tumors in the brain parenchyma is occasionally encountered on magnetic resonance (MR) images. This atypical enhanced cap tends to occur in severe peritumoral edema and may produce the characteristic bulge of a metastatic mass lesion termed the "comet tail sign" (CTS). The purpose of this study was to demonstrate the features of the CTS using MR imaging and pathological findings, and to clarify its clinical relevance. We selected 21 consecutive cases of newly diagnosed metastases from MR imaging studies that demonstrated the CTS; all had diffuse peritumoral edema. The MR T2-weighted images showed similarly homogenous and high intensity signals in both the tail and peritumoral edema. Fourteen of the 21 patients underwent surgical resection of their tumors, and 12 tails were separately removed for pathological examination, no tumor cells which revealed. We speculate that the CTS does not contain neoplastic tissues but is observed as a result of the leakage of contrast medium from the tumor body into the interstitial space of the white matter. Although CTS is a peculiar and uncommon enhancement pattern, it has clinical significance in determining the extent of the margin for invasive local treatments, such as surgical resection or stereotactic radiotherapy; this is particularly true in and near the eloquent areas.

Assessing Risks of Mine Tailing Dam Failures

NASA Astrophysics Data System (ADS)

Concha Larrauri, P.; Lall, U.

2017-12-01

The consequences of tailings dam failures can be catastrophic for communities and ecosystems in the vicinity of the dams. The failure of the Fundão tailings dam at the Samarco mine in 2015 killed 19 people with severe consequences for the environment. The financial and legal consequences of a tailings dam failure can also be significant for the mining companies. For the Fundão tailings dam, the company had to pay 6 billion dollars in fines and twenty-one executives were charged with qualified murder. There are tenths of thousands of active, inactive, and abandoned tailings dams in the world and there is a need to better understand the hazards posed by these structures to downstream populations and ecosystems. A challenge to assess the risks of tailings dams in a large scale is that many of them are not registered in publicly available databases and there is little information about their current physical state. Additionally, hazard classifications of tailings dams - common in many countries- tend to be subjective, include vague parameter definitions, and are not always updated over time. Here we present a simple methodology to assess and rank the exposure to tailings dams using ArcGIS that removes subjective interpretations. The method uses basic information such as current dam height, storage volume, topography, population, land use, and hydrological data. A hazard rating risk was developed to compare the potential extent of the damage across dams. This assessment provides a general overview of what in the vicinity of the tailings dams could be affected in case of a failure and a way to rank tailings dams that is directly linked to the exposure at any given time. One hundred tailings dams in Minas Gerais, Brazil were used for the test case. This ranking approach could inform the risk management strategy of the tailings dams within a company, and when disclosed, it could enable shareholders and the communities to make decisions on the risks they are taking.

A cis-prenyltransferase from Methanosarcina acetivorans catalyzes both head-to-tail and nonhead-to-tail prenyl condensation.

PubMed

Ogawa, Takuya; Emi, Koh-Ichi; Koga, Kazushi; Yoshimura, Tohru; Hemmi, Hisashi

2016-06-01

Cis-prenyltransferase usually consecutively catalyzes the head-to-tail condensation reactions of isopentenyl diphosphate to allylic prenyl diphosphate in the production of (E,Z-mixed) polyprenyl diphosphate, which is the precursor of glycosyl carrier lipids. Some recently discovered homologs of the enzyme, however, catalyze the nonhead-to-tail condensation reactions between allylic prenyl diphosphates. In this study, we characterize a cis-prenyltransferase homolog from a methanogenic archaeon, Methanosarcina acetivorans, to obtain information on the biosynthesis of the glycosyl carrier lipids within it. This enzyme catalyzes both head-to-tail and nonhead-to-tail condensation reactions. The kinetic analysis shows that the main reaction of the enzyme is consecutive head-to-tail prenyl condensation reactions yielding polyprenyl diphosphates, while the chain lengths of the major products seem shorter than expected for the precursor of glycosyl carrier lipids. On the other hand, a subsidiary reaction of the enzyme, i.e., nonhead-to-tail condensation between dimethylallyl diphosphate and farnesyl diphosphate, gives a novel diterpenoid compound, geranyllavandulyl diphosphate. © 2016 Federation of European Biochemical Societies.

The Carboxyl Tail of Connexin32 Regulates Gap Junction Assembly in Human Prostate and Pancreatic Cancer Cells*

PubMed Central

Katoch, Parul; Mitra, Shalini; Ray, Anuttoma; Kelsey, Linda; Roberts, Brett J.; Wahl, James K.; Johnson, Keith R.; Mehta, Parmender P.

2015-01-01

Connexins, the constituent proteins of gap junctions, are transmembrane proteins. A connexin (Cx) traverses the membrane four times and has one intracellular and two extracellular loops with the amino and carboxyl termini facing the cytoplasm. The transmembrane and the extracellular loop domains are highly conserved among different Cxs, whereas the carboxyl termini, often called the cytoplasmic tails, are highly divergent. We have explored the role of the cytoplasmic tail of Cx32, a Cx expressed in polarized and differentiated cells, in regulating gap junction assembly. Our results demonstrate that compared with the full-length Cx32, the cytoplasmic tail-deleted Cx32 is assembled into small gap junctions in human pancreatic and prostatic cancer cells. Our results further document that the expression of the full-length Cx32 in cells, which express the tail-deleted Cx32, increases the size of gap junctions, whereas the expression of the tail-deleted Cx32 in cells, which express the full-length Cx32, has the opposite effect. Moreover, we show that the tail is required for the clustering of cell-cell channels and that in cells expressing the tail-deleted Cx32, the expression of cell surface-targeted cytoplasmic tail alone is sufficient to enhance the size of gap junctions. Our live-cell imaging data further demonstrate that gap junctions formed of the tail-deleted Cx32 are highly mobile compared with those formed of full-length Cx32. Our results suggest that the cytoplasmic tail of Cx32 is not required to initiate the assembly of gap junctions but for their subsequent growth and stability. Our findings suggest that the cytoplasmic tail of Cx32 may be involved in regulating the permeability of gap junctions by regulating their size. PMID:25548281

The carboxyl tail of connexin32 regulates gap junction assembly in human prostate and pancreatic cancer cells.

PubMed

Katoch, Parul; Mitra, Shalini; Ray, Anuttoma; Kelsey, Linda; Roberts, Brett J; Wahl, James K; Johnson, Keith R; Mehta, Parmender P

2015-02-20

Connexins, the constituent proteins of gap junctions, are transmembrane proteins. A connexin (Cx) traverses the membrane four times and has one intracellular and two extracellular loops with the amino and carboxyl termini facing the cytoplasm. The transmembrane and the extracellular loop domains are highly conserved among different Cxs, whereas the carboxyl termini, often called the cytoplasmic tails, are highly divergent. We have explored the role of the cytoplasmic tail of Cx32, a Cx expressed in polarized and differentiated cells, in regulating gap junction assembly. Our results demonstrate that compared with the full-length Cx32, the cytoplasmic tail-deleted Cx32 is assembled into small gap junctions in human pancreatic and prostatic cancer cells. Our results further document that the expression of the full-length Cx32 in cells, which express the tail-deleted Cx32, increases the size of gap junctions, whereas the expression of the tail-deleted Cx32 in cells, which express the full-length Cx32, has the opposite effect. Moreover, we show that the tail is required for the clustering of cell-cell channels and that in cells expressing the tail-deleted Cx32, the expression of cell surface-targeted cytoplasmic tail alone is sufficient to enhance the size of gap junctions. Our live-cell imaging data further demonstrate that gap junctions formed of the tail-deleted Cx32 are highly mobile compared with those formed of full-length Cx32. Our results suggest that the cytoplasmic tail of Cx32 is not required to initiate the assembly of gap junctions but for their subsequent growth and stability. Our findings suggest that the cytoplasmic tail of Cx32 may be involved in regulating the permeability of gap junctions by regulating their size. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Mass stranding of wedge-tailed shearwater chicks in Hawaii

USGS Publications Warehouse

Work, Thierry M.; Rameyer, Robert

1999-01-01

Unusual numbers of wedge-tailed shearwater (Puffinus pacificus) chicks stranded on Oahu (Hawaii, USA) in 1994. Compared to healthy wedge-tailed shearwater (WTSW) chicks, stranded chicks were underweight, dehydrated, leukopenic, lymphopenic, eosinopenic, and heterophilic; some birds were toxemic and septic. Stranded chicks also were hypoglycemic and had elevated aspartate amino transferase levels. Most chicks apparently died from emaciation, dehydration, or bacteremia. Because many birds with bacteremia also had severe necrosis of the gastrointestinal (GI) mucosa associated with bacteria, we suspect the GI tract to be the source of disseminated bacterial infection. The identity of the bacteria was not confirmed. The daily number of chicks stranded was significantly related to average wind speeds, and the mortality coincided with the fledging period for WTSW. Strong southeasterly winds were a distinguishing meteorologic factor in 1994 and contributed to the distribution of stranded chicks on Oahu. More objective data on WTSW demographics would enhance future efforts to determine predisposing causes of WTSW wrecks and their effects on seabird colonies.

Disease limits populations: plague and black-tailed prairie dogs

USGS Publications Warehouse

Cully, Jack F.; Johnson, T.; Collinge, S.K.; Ray, C.

2010-01-01

Plague is an exotic vector-borne disease caused by the bacterium Yersinia pestis that causes mortality rates approaching 100% in black-tailed prairie dogs (Cynomys ludovicianus). We mapped the perimeter of the active portions of black-tailed prairie dog colonies annually between 1999 and 2005 at four prairie dog colony complexes in areas with a history of plague, as well as at two complexes that were located outside the distribution of plague at the time of mapping and had therefore never been affected by the disease. We hypothesized that the presence of plague would significantly reduce overall black-tailed prairie dog colony area, reduce the sizes of colonies on these landscapes, and increase nearest-neighbor distances between colonies. Within the region historically affected by plague, individual colonies were smaller, nearest-neighbor distances were greater, and the proportion of potential habitat occupied by active prairie dog colonies was smaller than at plague-free sites. Populations that endured plague were composed of fewer large colonies (>100 ha) than populations that were historically plague free. We suggest that these differences among sites in colony size and isolation may slow recolonization after extirpation. At the same time, greater intercolony distances may also reduce intercolony transmission of pathogens. Reduced transmission among smaller and more distant colonies may ultimately enhance long-term prairie dog population persistence in areas where plague is present.

Disease limits populations: plague and black-tailed prairie dogs.

PubMed

Cully, Jack F; Johnson, Tammi L; Collinge, Sharon K; Ray, Chris

2010-01-01

Plague is an exotic vector-borne disease caused by the bacterium Yersinia pestis that causes mortality rates approaching 100% in black-tailed prairie dogs (Cynomys ludovicianus). We mapped the perimeter of the active portions of black-tailed prairie dog colonies annually between 1999 and 2005 at four prairie dog colony complexes in areas with a history of plague, as well as at two complexes that were located outside the distribution of plague at the time of mapping and had therefore never been affected by the disease. We hypothesized that the presence of plague would significantly reduce overall black-tailed prairie dog colony area, reduce the sizes of colonies on these landscapes, and increase nearest-neighbor distances between colonies. Within the region historically affected by plague, individual colonies were smaller, nearest-neighbor distances were greater, and the proportion of potential habitat occupied by active prairie dog colonies was smaller than at plague-free sites. Populations that endured plague were composed of fewer large colonies (>100 ha) than populations that were historically plague free. We suggest that these differences among sites in colony size and isolation may slow recolonization after extirpation. At the same time, greater intercolony distances may also reduce intercolony transmission of pathogens. Reduced transmission among smaller and more distant colonies may ultimately enhance long-term prairie dog population persistence in areas where plague is present.

Disease Limits Populations: Plague and Black-Tailed Prairie Dogs

PubMed Central

Johnson, Tammi L.; Collinge, Sharon K.; Ray, Chris

2010-01-01

Abstract Plague is an exotic vector-borne disease caused by the bacterium Yersinia pestis that causes mortality rates approaching 100% in black-tailed prairie dogs (Cynomys ludovicianus). We mapped the perimeter of the active portions of black-tailed prairie dog colonies annually between 1999 and 2005 at four prairie dog colony complexes in areas with a history of plague, as well as at two complexes that were located outside the distribution of plague at the time of mapping and had therefore never been affected by the disease. We hypothesized that the presence of plague would significantly reduce overall black-tailed prairie dog colony area, reduce the sizes of colonies on these landscapes, and increase nearest-neighbor distances between colonies. Within the region historically affected by plague, individual colonies were smaller, nearest-neighbor distances were greater, and the proportion of potential habitat occupied by active prairie dog colonies was smaller than at plague-free sites. Populations that endured plague were composed of fewer large colonies (>100 ha) than populations that were historically plague free. We suggest that these differences among sites in colony size and isolation may slow recolonization after extirpation. At the same time, greater intercolony distances may also reduce intercolony transmission of pathogens. Reduced transmission among smaller and more distant colonies may ultimately enhance long-term prairie dog population persistence in areas where plague is present. PMID:20158327

Mobilization and transport of metal-rich colloidal particles from mine tailings into soil under transient chemical and physical conditions.

PubMed

Lu, Cong; Wu, Yaoguo; Hu, Sihai; Raza, Muhammad Ali; Fu, Yilin

2016-04-01

Exposed mine tailing wastes with considerable heavy metals can release hazardous colloidal particles into soil under transient chemical and physical conditions. Two-layered packed columns with tailings above and soils below were established to investigate mobilization and transport of colloidal particles from metal-rich mine tailings into soil under transient infiltration ionic strength (IS: 100, 20, 2 mM) and flow rate (FR: 20.7, 41, and 62.3 mm h(-1)), with Cu and Pb as representatives of the heavy metals. Results show that the tailing particles within the colloidal size (below 2 μm) were released from the columns. A step-decrease in infiltration IS and FR enhanced, whereas a step-increase in the IS and FR restrained the release of tailing particles from the column. The effects of step-changing FR were unexpected due to the small size of the released tailing particles (220-342 nm, being not sensitive to hydrodynamic shear force), the diffusion-controlled particle release process and the relatively compact pore structure. The tailing particles present in the solution with tested IS were found negatively charged and more stable than soil particles, which provides favorable conditions for tailing particles to be transported over a long distance in the soil. The mobilization and transport of Cu and Pb from the tailings into soil were mediated by the tailing particles. Therefore, the inherent toxic tailing particles could be considerably introduced into soil under certain conditions (IS reduction or FR decrease), which may result in serious environmental pollution.

VARIATION OF SPECTRAL AND TIMING PROPERTIES IN THE EXTENDED BURST TAILS FROM THE MAGNETAR 4U 0142+61

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, Manoneeta; Göğüş, Ersin; Muş, Sinem Şaşmaz

2016-03-10

Extended emission episodes with an intensity above the preburst level are observed following magnetar bursts from a number of soft gamma repeaters and anomalous X-ray pulsars (AXPs). Such extended tail emissions were observed following two events detected from AXP 4U 0142+61. We investigated in detail the evolution of spectral and temporal properties during these two tail segments using Rossi X-ray Timing Explorer/Proportional Counter Array observations, and report distinct variations in the spectral and temporal behavior throughout the tails. In particular, in both cases we observed a sudden enhancement of the pulsation amplitude in conjunction with bursts and a smooth declinemore » of X-ray emission (cooling) during the tail. We suggest that an inefficiently radiating trapped fireball formed during the burst, which can heat up the stellar surface, is able to explain the tail properties and its energetics. We also present the episodic detection of absorption and emission features during tails. One possible mechanism that has been proposed to give rise to such spectral lines is the proton/ion cyclotron resonance process, which has been suggested as offering a valuable tool in probing the complex magnetic field of magnetars.« less

The X-ray Crystal Structure of the Phage Tail Terminator Protein Reveals the Biologically Relevant Hexameric Rang Structure and Demonstrates a Conserved mechanism of Tail Termination among Divrse Long Tailed Phages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pell, L.; Liu, A; Edmonds, L

The tail terminator protein (TrP) plays an essential role in phage tail assembly by capping the rapidly polymerizing tail once it has reached its requisite length and serving as the interaction surface for phage heads. Here, we present the 2.7-A crystal structure of a hexameric ring of gpU, the TrP of phage ?. Using sequence alignment analysis and site-directed mutagenesis, we have shown that this multimeric structure is biologically relevant and we have delineated its functional surfaces. Comparison of the hexameric crystal structure with the solution structure of gpU that we previously solved using NMR spectroscopy shows large structural changesmore » occurring upon multimerization and suggests a mechanism that allows gpU to remain monomeric at high concentrations on its own, yet polymerize readily upon contact with an assembled tail tube. The gpU hexamer displays several flexible loops that play key roles in head and tail binding, implying a role for disorder-to-order transitions in controlling assembly as has been observed with other ? morphogenetic proteins. Finally, we have found that the hexameric structure of gpU is very similar to the structure of a putative TrP from a contractile phage tail even though it displays no detectable sequence similarity. This finding coupled with further bioinformatic investigations has led us to conclude that the TrPs of non-contractile-tailed phages, such as ?, are evolutionarily related to those of contractile-tailed phages, such as P2 and Mu, and that all long-tailed phages may utilize a conserved mechanism for tail termination.« less

Evaluation Of The Advanced Operating System Of The Ann Arbor Transportation Authority : Cost Study : Before, During And After AOS Implementation (October 1996-May 1999)

DOT National Transportation Integrated Search

1999-01-01

In 1997, the Ann Arbor (Michigan) Transportation Authority (AATA) began deploying advanced public transportation systems (APTS) technologies in its fixed route and paratransit operations. The project's concept is the integration of a range of such te...

Proceedings of Workshop on Priority Great Lakes Environmental Research Initiatives (Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan, October 10-11, 1974).

ERIC Educational Resources Information Center

Pinsak, Arthur P., Ed.

This publication contains the proceedings of a workshop held in Ann Arbor, Michigan to identify the priority Great Lakes environmental research initiatives. The five major objectives of the workshop include the determination of research initiatives, opportunities for university research communities to discuss and recommend future research…

EAR AND TAIL LESIONS ON CAPTIVE WHITE-TAILED DEER FAWNS (ODOCOILEUS VIRGINIANUS): A CASE STUDY.

PubMed

Ferguson, Treena L; Demarais, Stephen; Cooley, Jim; Fleming, Sherrill; Michel, Eric S; Flinn, Emily

2016-06-01

During the 2008-2011 time period, undiagnosed lesions were observed in 21 of 150 white-tailed deer fawns (Odocoileus virginianus) that were part of a captive deer herd at Mississippi State University. Clinical findings in healthy and diseased fawns from 0 to 90 days of age included bite and scratch marks followed by moderate to severe ear and tail necrosis. Gross necropsy findings of necrotizing ulcerative dermatitis correlated with histopathologic findings that included focally severe multifocal vasculitis, vascular necrosis, and thrombosis. This article is a clinical description of these previously unreported lesions associated with tissue necrosis in young captive white-tailed deer.

On the average configuration of the geomagnetic tail

NASA Technical Reports Server (NTRS)

Fairfield, D. H.

1978-01-01

Over 3000 hours of IMP-6 magnetic field data obtained between 20 and 33 R sub E in the geomagnetic tail have been used in a statistical study of the tail configuration. A distribution of 2.5 minute averages of B sub Z as a function of position across the tail reveals that more flux crosses the equatorial plane near the dawn and dusk flanks than near midnight. The tail field projected in the solar magnetospheric equatorial plane deviates from the X axis due to flaring and solar wind aberration by an angle alpha = -0.9 y sub SM - 1.7 where Y sub SM is in earth radii and alpha is in degrees. After removing these effects the Y component of the tail field is found to depend on interplanetary sector structure. During an away sector the B sub Y component of the tail field is on average 0.5 gamma greater than that during a toward sector, a result that is true in both tail lobes and is independent of location across the tail.

Lengthening of the Stargazin Cytoplasmic Tail Increases Synaptic Transmission by Promoting Interaction to Deeper Domains of PSD-95.

PubMed

Hafner, Anne-Sophie; Penn, Andrew C; Grillo-Bosch, Dolors; Retailleau, Natacha; Poujol, Christel; Philippat, Amandine; Coussen, Françoise; Sainlos, Matthieu; Opazo, Patricio; Choquet, Daniel

2015-04-22

PSD-95 is a prominent organizer of the postsynaptic density (PSD) that can present a filamentous orientation perpendicular to the plasma membrane. Interactions between PSD-95 and transmembrane proteins might be particularly sensitive to this orientation, as "long" cytoplasmic tails might be required to reach deeper PSD-95 domains. Extension/retraction of transmembrane protein C-tails offer a new way of regulating binding to PSD-95. Using stargazin as a model, we found that enhancing the apparent length of stargazin C-tail through phosphorylation or by an artificial linker was sufficient to potentiate binding to PSD-95, AMPAR anchoring, and synaptic transmission. A linear extension of stargazin C-tail facilitates binding to PSD-95 by preferentially engaging interaction with the farthest located PDZ domains regarding to the plasma membrane, which present a greater affinity for the stargazin PDZ-domain-binding motif. Our study reveals that the concerted orientation of the stargazin C-tail and PSD-95 is a major determinant of synaptic strength. Copyright © 2015 Elsevier Inc. All rights reserved.

Why are most EU pigs tail docked? Economic and ethical analysis of four pig housing and management scenarios in the light of EU legislation and animal welfare outcomes.

PubMed

D'Eath, R B; Niemi, J K; Vosough Ahmadi, B; Rutherford, K M D; Ison, S H; Turner, S P; Anker, H T; Jensen, T; Busch, M E; Jensen, K K; Lawrence, A B; Sandøe, P

2016-04-01

To limit tail biting incidence, most pig producers in Europe tail dock their piglets. This is despite EU Council Directive 2008/120/EC banning routine tail docking and allowing it only as a last resort. The paper aims to understand what it takes to fulfil the intentions of the Directive by examining economic results of four management and housing scenarios, and by discussing their consequences for animal welfare in the light of legal and ethical considerations. The four scenarios compared are: 'Standard Docked', a conventional housing scenario with tail docking meeting the recommendations for Danish production (0.7 m2/pig); 'Standard Undocked', which is the same as 'Standard Docked' but with no tail docking, 'Efficient Undocked' and 'Enhanced Undocked', which have increased solid floor area (0.9 and 1.0 m2/pig, respectively) provision of loose manipulable materials (100 and 200 g/straw per pig per day) and no tail docking. A decision tree model based on data from Danish and Finnish pig production suggests that Standard Docked provides the highest economic gross margin with the least tail biting. Given our assumptions, Enhanced Undocked is the least economic, although Efficient Undocked is better economically and both result in a lower incidence of tail biting than Standard Undocked but higher than Standard Docked. For a pig, being bitten is worse for welfare (repeated pain, risk of infections) than being docked, but to compare welfare consequences at a farm level means considering the number of affected pigs. Because of the high levels of biting in Standard Undocked, it has on average inferior welfare to Standard Docked, whereas the comparison of Standard Docked and Enhanced (or Efficient) Undocked is more difficult. In Enhanced (or Efficient) Undocked, more pigs than in Standard Docked suffer from being tail bitten, whereas all the pigs avoid the acute pain of docking endured by the pigs in Standard Docked. We illustrate and discuss this ethical balance using

Workshop on Surface Science and Technology Held in Ann Arbor, Michigan on 7-9 November 1990

DTIC Science & Technology

1992-03-01

assess the state of the art of surface science and technology as well as to identify new research opportunities essential for the understanding and control...The objective of this workshop was to review and assess the state of the art of surface science and technology as well as to identify new research...AD-A253 566 ’ # 4 - m~~i n~nl lInIir ~~ na Ri1 ?epoi’rt: EN 1Workshop on Surface Science and Technology DTIC ft , L-CTE I OUG0 3192 Ann Arbor

Development of a dust deposition forecast model for a mine tailings impoundment

NASA Astrophysics Data System (ADS)

Stovern, Michael

that influence deposition. Simulation results indicated that particles preferentially deposit in regions of topographic upslope. In addition, turbulent wind fields enhanced deposition in the wake region downwind of the tailings. This study also describes a deposition forecasting model (DFM) that can be used to forecast the transport and deposition of windblown dust originating from a mine tailings impoundment. The DFM uses in situ observations from the tailings and theoretical simulations of aerosol transport to parameterize the model. The model was verified through the use of inverted-disc deposition samplers. The deposition forecasting model was initialized using data from an operational Weather Research and Forecasting (WRF) model and the forecast deposition patterns were compared to the inverted-disc samples through gravimetric, chemical composition and lead isotopic analysis. The DFM was verified over several month-long observing periods by comparing transects of arsenic and lead tracers measured by the samplers to the DFM PM27 forecast. Results from the sampling periods indicated that the DFM was able to accurately capture the regional deposition patterns of the tailings dust up to 1 km. Lead isotopes were used for source apportionment and showed spatial patterns consistent with the DFM and the observed weather conditions. By providing reasonably accurate estimates of contaminant deposition rates, the DFM can improve the assessment of human health impacts caused by windblown dust from the Iron King tailings impoundment.

Tail Shape Design of Boat Wind Turbines

NASA Astrophysics Data System (ADS)

Singamsitty, Venkatesh

Wind energy is a standout among the most generally utilized sustainable power source assets. A great deal of research and improvements have been happening in the wind energy field. Wind turbines are mechanical devices that convert kinetic energy into electrical power. Boat wind turbines are for the small-scale generation of electric power. In order to catch wind energy effectively, boat wind turbines need to face wind direction. Tails are used in boat wind turbines to alter the wind turbine direction and receive the variation of the incoming direction of wind. Tails are used to change the performance of boat wind turbines in an effective way. They are required to generate a quick and steady response as per change in wind direction. Tails can have various shapes, and their effects on boat wind turbines are different. However, the effects of tail shapes on the performance of boat wind turbines are not thoroughly studied yet. In this thesis, five tail shapes were studied. Their effects on boat wind turbines were investigated. The power extracted by the turbines from the air and the force acting on the boat wind turbine tail were analyzed. The results of this thesis provide a guideline of tail shape design for boat wind turbines.

Quasi-steady state aerodynamics of the cheetah tail

PubMed Central

Boje, Edward; Fisher, Callen; Louis, Leeann; Lane, Emily

2016-01-01

ABSTRACT During high-speed pursuit of prey, the cheetah (Acinonyx jubatus) has been observed to swing its tail while manoeuvring (e.g. turning or braking) but the effect of these complex motions is not well understood. This study demonstrates the potential of the cheetah's long, furry tail to impart torques and forces on the body as a result of aerodynamic effects, in addition to the well-known inertial effects. The first-order aerodynamic forces on the tail are quantified through wind tunnel testing and it is observed that the fur nearly doubles the effective frontal area of the tail without much mass penalty. Simple dynamic models provide insight into manoeuvrability via simulation of pitch, roll and yaw tail motion primitives. The inertial and quasi-steady state aerodynamic effects of tail actuation are quantified and compared by calculating the angular impulse imparted onto the cheetah's body and its shown aerodynamic effects contribute to the tail's angular impulse, especially at the highest forward velocities. PMID:27412267

Wing-Fuselage Interference, Tail Buffeting, and Air Flow About the Tail of a Low-Wing Monoplane

NASA Technical Reports Server (NTRS)

White, James A; Hood, Manley J

1935-01-01

This report presents the results of wind tunnel tests on a Mcdonnell Douglas airplane to determine the wing-fuselage interference of a low-wing monoplane. The tests included a study of tail buffeting and the air flow in the region of the tail. The airplane was tested with and without the propeller slipstream, both in the original condition and with several devices designed to reduce or eliminate tail buffeting. The devices used were wing-fuselage fillets, a NACA cowling, reflexed trailing edge of the wing, and stub auxiliary airfoils.

Four tails problems for dynamical collapse theories

NASA Astrophysics Data System (ADS)

McQueen, Kelvin J.

2015-02-01

The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem dilemma) shows that solving the third by replacing the Gaussian with a non-Gaussian collapse function introduces new conflict with relativity theory.

Aided phytostabilisation reduces metal toxicity, improves soil fertility and enhances microbial activity in Cu-rich mine tailings.

PubMed

Touceda-González, M; Álvarez-López, V; Prieto-Fernández, Á; Rodríguez-Garrido, B; Trasar-Cepeda, C; Mench, M; Puschenreiter, M; Quintela-Sabarís, C; Macías-García, F; Kidd, P S

2017-01-15

(Aided) phytostabilisation has been proposed as a suitable technique to decrease the environmental risks associated with metal(loid)-enriched mine tailings. Field scale evaluations are needed for demonstrating their effectiveness in the medium- to long-term. A field trial was implemented in spring 2011 in Cu-rich mine tailings in the NW of Spain. The tailings were amended with composted municipal solid wastes and planted with Salix spp., Populus nigra L. or Agrostis capillaris L. cv. Highland. Plant growth, nutritive status and metal accumulation, and soil physico- and bio-chemical properties, were monitored over three years (four years for plant growth). The total bacterial community, α- and β-Proteobacteria, Actinobacteria and Streptomycetaceae were studied by DGGE of 16s rDNA fragments. Compost amendment improved soil properties such as pH, CEC and fertility, and decreased soil Cu availability, leading to the establishment of a healthy vegetation cover. Both compost-amendment and plant root activity stimulated soil enzyme activities and induced important shifts in the bacterial community structure over time. The woody plant, S. viminalis, and the grassy species, A. capillaris, showed the best results in terms of plant growth and biomass production. The beneficial effects of the phytostabilisation process were maintained at least three years after treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Some Effects of Horizontal-Tail Position on the Vertical-Tail Pressure Distributions of a Complete Model in Sideslip at High Subsonic Speeds

NASA Technical Reports Server (NTRS)

Alford, William J., Jr.

1958-01-01

An investigation has been made in the Langley high-speed 7- by 10-foot tunnel of some effects of horizontal-tail position on the vertical-tail pressure distributions of a complete model in sideslip at high subsonic speeds. The wing of the model was swept back 28.82 deg at the quarter-chord line and had an aspect ratio of 3.50, a taper ratio of 0.067, and NACA 65A004 airfoil sections parallel to the model plane of symmetry. Tests were made with the horizontal tail off, on the wing-chord plane extended, and in T-tail arrangements in forward and rearward locations. The test Mach numbers ranged from 0.60 to 0.92, which corresponds to a Reynolds number range from approximately 2.93 x 10(exp 6) to 3.69 x 10(exp 6), based on the wing mean aerodynamic chord. The sideslip angles varied from -3.9 deg to 12.7 deg at several selected angles of attack. The results indicated that, for a given angle of sideslip, increases in angle of attack caused reductions in the vertical-tail loads in the vicinity of the root chord and increases at the midspan and tip locations, with rearward movements in the local chordwise centers of pressure for the midspan locations and forward movements near the tip of the vertical tail. At the higher angles of attack all configurations investigated experienced outboard and rearward shifts in the center of pressure of the total vertical-tail load. Location of the horizontal tail on the wing- chord plane extended produced only small effects on the vertical-tail loads and centers of pressure. Locating the horizontal tail at the tip of the vertical tail in the forward position caused increases in the vertical-tail loads; this configuration, however, experienced considerable reduction in loads with increasing Mach number. Location of the horizontal tail at the tip of the vertical tail in the rearward position produced the largest increases in vertical-tail loads per degree sideslip angle; this configuration experienced the smallest variations of loads with

A new species of arboreal toad (Anura : Bufonidae : Chaunus) from Madidi National Park, Bolivia

USGS Publications Warehouse

Padial, J.M.; Reichle, S.; McDiarmid, R.; De la Riva, I.

2006-01-01

A new arboreal species of the Chaunus veraguensis group is described for the humid montane forest of Madidi National Park, in northern Bolivia. The new species differs from other species in the group by the combination small size, long and slender extremities, webbed hands, conspicuous tympanic membrane, well developed parotoid glands, absence of large glands on dorsum and extremities, nuptial excrescences of males composed of pungent spines on dorsal surface of thumb, greenish-brown coloration on dorsum with red warts in life, and green iris. It is only known from two nearby localities in the Serran Eslabon, Department La Paz. An operational key for species in the C. veraguensis group is provided.

The Distant Sodium Tail of Mercury

NASA Technical Reports Server (NTRS)

Potter, A. E.; Killen, R. M.; Morgan, T. H.

2001-01-01

Models of the sodium atmosphere of Mercury predict the possible existence of a cornet-like sodium tail. Detection and mapping of the predicted sodium tail would provide quantitative data on the energy of the process that produces sodium atoms from the planetary surface. Previous efforts to detect the sodium tail by means of observations done during daylight hours have been only partially successful because scattered sunlight obscured the weak sodium emissions in the tail. However, at greatest eastern elongation around the March equinox in the northern hemisphere, Mercury can be seen as an evening star in astronomical twilight. At this time, the intensity of scattered sunlight is low enough that sodium emissions as low as 500 Rayleighs can be detected. Additional information is contained in the original extended abstract.

Cross-tail current, field-aligned current, and B(y)

NASA Technical Reports Server (NTRS)

Kaufmann, Richard L.; Lu, Chen; Larson, Douglas J.

1994-01-01

Orbits of individual charged particles were traced in a one-dimensional magnetic field model that included a uniform cross-tail component B(sub yo). The effects of B(sub yo) on the cross-tail current distribution j(sub y)(z), the average cross-tail drift velocity(nu(sub y)z), and the average pitch angle change(delta alpha) experienced during current sheet encounters were calculated. The addition of a B(sub yo) that exceeded several tenths of one nanotesla completely eliminated all resonance effects for odd-N orbits. An odd-N resonance involves ions that enter and exit the current sheet on the same side. Pitch angles of nearly all such ions changed substantially during a typical current sheet interaction, and there was no region of large cross-tail drift velocity in the presence of a modest B(sub yo). the addition of a very large B(sub yo) guide field in the direction that enhances the natural drift produces a large j(y) and small (Delta alpha) for ions with all energies. The addition of a modest B(sub yo) had less effect near even-N resonances. In this case, ions in a small energy range were found to undergo so little change in pitch angle that particles which originated in the ionosphere would pass through the current sheet and return to the conjugate ionosphere. Finally, the cross-tail drift of ions from regions dominated by stochastic orbits to regions dominated by either resonant or guiding center orbits was considered. The ion drift speed changed substantially during such transitions. The accompanying electrons obey the guiding center equations, so electron drift is more uniform. Any difference between gradients in the fluxes associated with electron and ion drifts requires the presence of a Birkeland current in order to maintain charge neutrality. This plasma sheet region therefore serves as a current generator. The analysis predicts that the resulting Birkeland current connects to the lowest altitude equatorial regions in which ions drift to or from a point

Comparison of the plasma tails of four comets: P/Halley, Okazaki-Levy-Rudenko, Austin, and Levy

NASA Technical Reports Server (NTRS)

Farnham, Tony L.; Meech, Karen J.

1994-01-01

Photographic and charge coupled device (CCD) plasma tail observations are compared for four comets: P/Halley (22 nights in 1985/1986), Okazaki-Levy-Rudenko 1989 XIX (1989 December 2), Austin 1990 V (nine nights in 1990), and Levy 1990 XX (two nights in 1991). We present a discussion of several image-processing techniques used to enhance the visibility of the plasma tail features in order to measure velocities, accelerations, and position angles. The data are used to assess the validity of various physical mechanisms proposed to explain plasma tail phenomena. Seven disconnection events were observed in the comet P/Halley data, two in the Austin data, and none for the other comets. Analysis of these data suggests that while the crossing of the solar neutral sheet (the sector boundary) is a prominent factor in the production of a disconnection event, it is likely that several mechanisms are at work. A sector boundary crossing has been ruled out as the cause of either the 1986 April 26 P/Halley disconnection or the 1990 May 5/6 Austin disconnection. The motions of the disconnection events, knots, and condensations in the tails were seen to increase from 30-60 km/s near the nucleus (within 10(exp 6) km) to 80-100 km/s at 10(exp 7) km, consistent with either bulk motion or Alfven waves. Distinguishing between the two cases is not possible with these data. It was found that although the tail ray rotation rate slows as the ray approaches the tail axis, it is not a good indicator of the solar wind speed. Historical plasma tail data are also used to look for clues as to why some comets form well-developed plasma tails and others do not.

Black-tailed and white-tailed jackrabbits in the American West: History, ecology, ecological significance, and survey methods

USGS Publications Warehouse

Simes, Matthew; Longshore, Kathleen M.; Nussear, Kenneth E.; Beatty, Greg L.; Brown, David E.; Esque, Todd C.

2015-01-01

Across the western United States, Leporidae are the most important prey item in the diet of Golden Eagles (Aquila chrysaetos). Leporids inhabiting the western United States include black-tailed (Lepus californicus) and white-tailed jackrabbits (Lepus townsendii) and various species of cottontail rabbit (Sylvilagus spp.). Jackrabbits (Lepus spp.) are particularly important components of the ecological and economic landscape of western North America because their abundance influences the reproductive success and population trends of predators such as coyotes (Canis latrans), bobcats (Lynx rufus), and a number of raptor species. Here, we review literature pertaining to black-tailed and white-tailed jackrabbits comprising over 170 published journal articles, notes, technical reports, conference proceedings, academic theses and dissertations, and other sources dating from the late 19th century to the present. Our goal is to present information to assist those in research and management, particularly with regard to protected raptor species (e.g., Golden Eagles), mammalian predators, and ecological monitoring. We classified literature sources as (1) general information on jackrabbit species, (2) black-tailed or (3) white-tailed jackrabbit ecology and natural history, or (4) survey methods. These categories, especially 2, 3, and 4, were further subdivided as appropriate. The review also produced several tables on population trends, food habits, densities within various habitats, and jackrabbit growth and development. Black-tailed and white-tailed jackrabbits are ecologically similar in general behaviors, use of forms, parasites, and food habits, and they are prey to similar predators; but they differ in their preferred habitats. While the black-tailed jackrabbit inhabits agricultural land, deserts, and shrublands, the white-tailed jackrabbit is associated with prairies, alpine tundra, and sagebrush-steppe. Frequently considered abundant, jackrabbit numbers in western North

The boron-tailing myth in hydrogenated amorphous silicon solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stuckelberger, M., E-mail: michael.stuckelberger@alumni.ethz.ch; Bugnon, G.; Despeisse, M.

The boron-tailing effect in hydrogenated amorphous silicon (a-Si:H) solar cells describes the reduced charge collection specifically in the blue part of the spectrum for absorber layers deposited above a critical temperature. This effect limits the device performance of state-of-the art solar cells: For enhanced current density (reduced bandgap), the deposition temperature should be as high as possible, but boron tailing gets detrimental above 200 °C. To investigate this limitation and to show potential paths to overcome it, we deposited high-efficiency a-Si:H solar cells, varying the deposition temperatures of the p-type and the intrinsic absorber (i) layers between 150 and 250 °C. Usingmore » secondary ion mass spectroscopy, we study dedicated stacks of i-p-i layers deposited at different temperatures. This allows us to track boron diffusion at the p-i and i-p interfaces as they occur in the p-i-n and n-i-p configurations of a-Si:H solar cells for different deposition conditions. Finally, we prove step-by-step that the common explanation for boron tailing—boron diffusion from the p layer into the i layer leading to enhanced recombination—is not generally true and propose an alternative explanation for the experimentally observed drop in the external quantum efficiency at short wavelengths.« less

Heavy Tail Behavior of Rainfall Extremes across Germany

NASA Astrophysics Data System (ADS)

Castellarin, A.; Kreibich, H.; Vorogushyn, S.; Merz, B.

2017-12-01

Distributions are termed heavy-tailed if extreme values are more likely than would be predicted by probability distributions that have exponential asymptotic behavior. Heavy-tail behavior often leads to surprise, because historical observations can be a poor guide for the future. Heavy-tail behavior seems to be widespread for hydro-meteorological extremes, such as extreme rainfall and flood events. To date there have been only vague hints to explain under which conditions these extremes show heavy-tail behavior. We use an observational data set consisting of 11 climate variables at 1440 stations across Germany. This homogenized, gap-free data set covers 110 years (1901-2010) at daily resolution. We estimate the upper tail behavior, including its uncertainty interval, of daily precipitation extremes for the 1,440 stations at the annual and seasonal time scales. Different tail indicators are tested, including the shape parameter of the Generalized Extreme Value distribution, the upper tail ratio and the obesity index. In a further step, we explore to which extent the tail behavior can be explained by geographical and climate factors. A large number of characteristics is derived, such as station elevation, degree of continentality, aridity, measures for quantifying the variability of humidity and wind velocity, or event-triggering large-scale atmospheric situation. The link between the upper tail behavior and these characteristics is investigated via data mining methods capable of detecting non-linear relationships in large data sets. This exceptionally rich observational data set, in terms of number of stations, length of time series and number of explaining variables, allows insights into the upper tail behavior which is rarely possible given the typical observational data sets available.

Quasi-steady state aerodynamics of the cheetah tail.

PubMed

Patel, Amir; Boje, Edward; Fisher, Callen; Louis, Leeann; Lane, Emily

2016-08-15

During high-speed pursuit of prey, the cheetah (Acinonyx jubatus) has been observed to swing its tail while manoeuvring (e.g. turning or braking) but the effect of these complex motions is not well understood. This study demonstrates the potential of the cheetah's long, furry tail to impart torques and forces on the body as a result of aerodynamic effects, in addition to the well-known inertial effects. The first-order aerodynamic forces on the tail are quantified through wind tunnel testing and it is observed that the fur nearly doubles the effective frontal area of the tail without much mass penalty. Simple dynamic models provide insight into manoeuvrability via simulation of pitch, roll and yaw tail motion primitives. The inertial and quasi-steady state aerodynamic effects of tail actuation are quantified and compared by calculating the angular impulse imparted onto the cheetah's body and its shown aerodynamic effects contribute to the tail's angular impulse, especially at the highest forward velocities. © 2016. Published by The Company of Biologists Ltd.

The Sodium Tail of the Moon

NASA Technical Reports Server (NTRS)

Matta, M.; Smith, S.; Baumgardner, J.; Wilson, J.; Martinis, C.; Mendillo, M.

2009-01-01

During the few days centered about new Moon, the lunar surface is optically hidden from Earth-based observers. However, the Moon still offers an observable: an extended sodium tail. The lunar sodium tail is the escaping "hot" component of a coma-like exosphere of sodium generated by photon-stimulated desorption, solar wind sputtering and meteoroid impact. Neutral sodium atoms escaping lunar gravity experience solar radiation pressure that drives them into the anti-solar direction forming a comet-like tail. During new Moon time, the geometry of the Sun, Moon and Earth is such that the anti-sunward sodium flux is perturbed by the terrestrial gravitational field resulting in its focusing into a dense core that extends beyond the Earth. An all-sky camera situated at the El Leoncito Observatory (CASLEO) in Argentina has been successfully imaging this tail through a sodium filter at each lunation since April 2006. This paper reports on the results of the brightness of the lunar sodium tail spanning 31 lunations between April 2006 and September 2008. Brightness variability trends are compared with both sporadic and shower meteor activity, solar wind proton energy flux and solar near ultra violet (NUV) patterns for possible correlations. Results suggest minimal variability in the brightness of the observed lunar sodium tail, generally uncorrelated with any single source, yet consistent with a multi-year period of minimal solar activity and non-intense meteoric fluxes.

Observations of Ion Diffusion Regions in the Geomagnetic Tail

NASA Astrophysics Data System (ADS)

Rogers, A. J.; Farrugia, C. J.; Torbert, R. B.; Argall, M. R.; Strangeway, R. J.; Ergun, R.

2017-12-01

We present analysis of two Ion Diffusion Regions (IDRs) in the geomagnetic tail, as observed by the Magnetospheric Multiscale Mission (MMS). Analysis of each event is centered around discussion of parameters commonly associated with IDRs such as enhanced electric field magnitude, guiding center expansion parameter, and ion velocity. Characteristic values for these parameters are determined, as well as other common attributes of IDRs, and used to develop a searching algorithm to automate identification of possible IDRs for closer inspection. Preliminary results of applying this algorithm to in situ MMS observations are also presented

Physical space and long-tail markets

NASA Astrophysics Data System (ADS)

Bentley, R. Alexander; Madsen, Mark E.; Ormerod, Paul

2009-03-01

The Internet is known to have had a powerful impact on on-line retailer strategies in markets characterised by long-tail distribution of sales [C. Anderson, Long Tail: Why the Future of Business is Selling Less of More, Hyperion, New York, 2006]. Such retailers can exploit the long tail of the market, since they are effectively without physical limit on the number of choices on offer. Here we examine two extensions of this phenomenon. First, we introduce turnover into the long-tail distribution of sales. Although over any given period such as a week or a month, the distribution is right-skewed and often power law distributed, over time there is considerable turnover in the rankings of sales of individual products. Second, we establish some initial results on the implications for shelf-space and physical retailers in such markets.

[Effects of bio-crust on soil microbial biomass and enzyme activities in copper mine tailings].

PubMed

Chen, Zheng; Yang, Gui-de; Sun, Qing-ye

2009-09-01

Bio-crust is the initial stage of natural primary succession in copper mine tailings. With the Yangshanchong and Tongguanshan copper mine tailings in Tongling City of Anhui Province as test objects, this paper studied the soil microbial biomass C and N and the activities of dehydrogenase, catalase, alkaline phosphatase, and urease under different types of bio-crust. The bio-crusts improved the soil microbial biomass and enzyme activities in the upper layer of the tailings markedly. Algal crust had the best effect in improving soil microbial biomass C and N, followed by moss-algal crust, and moss crust. Soil microflora also varied with the type of bio-crust. No'significant difference was observed in the soil enzyme activities under the three types of bio-crust. Soil alkaline phosphatase activity was significantly positively correlated with soil microbial biomass and dehydrogenase and urease activities, but negatively correlated with soil pH. In addition, moss rhizoid could markedly enhance the soil microbial biomass and enzyme activities in moss crust rhizoid.

Metal mobilization under alkaline conditions in ash-covered tailings.

PubMed

Lu, Jinmei; Alakangas, Lena; Wanhainen, Christina

2014-06-15

The aim of this study was to determine element mobilization and accumulation in mill tailings under alkaline conditions. The tailings were covered with 50 cm of fly ash, and above a sludge layer. The tailings were geochemically and mineralogically investigated. Sulfides, such as pyrrhotite, sphalerite and galena along with gangue minerals such as dolomite, calcite, micas, chlorite, epidote, Mn-pyroxene and rhodonite were identified in the unoxidized tailings. The dissolution of the fly ash layer resulted in a high pH (close to 12) in the underlying tailings. This, together with the presence of organic matter, increased the weathering of the tailings and mobilization of elements in the uppermost 47 cm of the tailings. All primary minerals were depleted, except quartz and feldspar which were covered by blurry secondary carbonates. Sulfide-associated elements such as Cd, Fe, Pb, S and Zn and silicate-associated elements such as Fe, Mg and Mn were released from the depletion zone and accumulated deeper down in the tailings where the pH decreased to circum-neutral. Sequential extraction suggests that Cd, Cu, Fe, Pb, S and Zn were retained deeper down in the tailings and were mainly associated with the sulfide phase. Calcium, Cr, K and Ni released from the ash layer were accumulated in the uppermost depletion zone of the tailings. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rock-dwelling lizards exhibit less sensitivity of sprint speed to increases in substrate rugosity.

PubMed

Collins, Clint E; Self, Jessica D; Anderson, Roger A; McBrayer, Lance D

2013-06-01

Effectively moving across variable substrates is important to all terrestrial animals. The effects of substrates on lizard performance have ecological ramifications including the partitioning of habitat according to sprinting ability on different surfaces. This phenomenon is known as sprint sensitivity, or the decrease in sprint speed due to change in substrate. However, sprint sensitivity has been characterized only in arboreal Anolis lizards. Our study measured sensitivity to substrate rugosity among six lizard species that occupy rocky, sandy, and/or arboreal habitats. Lizards that use rocky habitats are less sensitive to changes in substrate rugosity, followed by arboreal lizards, and then by lizards that use sandy habitats. We infer from comparative phylogenetic analysis that forelimb, chest, and tail dimensions are important external morphological features related to sensitivity to changes in substrate rugosity. Copyright © 2013 Elsevier GmbH. All rights reserved.

Radioactivity and radiological risk associated with effluent sediment containing technologically enhanced naturally occurring radioactive materials in amang (tin tailings) processing industry.

PubMed

Bahari, Ismail; Mohsen, Nasirian; Abdullah, Pauzi

2007-01-01

The processing of amang, or tin tailings, for valuable minerals has been shown to technologically enhance NORM and this has stirred significant radiological safety and health concerns among Malaysia's regulatory authority. A growing radiological concern is now focused on the amang effluent containing NORM in recycling ponds, since these ponds may be reclaimed for future residential developments. A study was carried out to assess the radiological risk associated with amang processing and the accumulated effluent in the recycling ponds. Twenty-six sediment samples from the recycling ponds of two amang plants in the states of Selangor and Perak, Malaysia, were collected and analyzed. The maximum activity concentrations of (238)U, (226)Ra, (232)Th and (40)K recorded in sediments from these ponds were higher than Malaysia's and the world's natural highest. Correspondingly, the mean radium equivalent activity concentration indices, Ra(eq), and gamma radiation representative level index, I(gammar), were higher than the world's average. The enhancement of NORM in effluent sediments as a consequence of amang processing, and the use of a closed water management recycling system created Effective Dose Rates, E (nSv h(-1)), that signal potential environmental radiological risks in these ponds, should they be reclaimed for future land use.

Enhanced nitrogen removal from electroplating tail wastewater through two-staged anoxic-oxic (A/O) process.

PubMed

Yan, Xinmei; Zhu, Chunyan; Huang, Bin; Yan, Qun; Zhang, Guangsheng

2018-01-01

Consisted of anaerobic (ANA), anoxic-1 (AN1), aerobic-1 (AE1), anoxic-2 (AN2), aerobic-2 (AE2) reactors and sediment tank, the two-staged A/O process was applied for depth treatment of electroplating tail wastewater with high electrical conductivity and large amounts of ammonia nitrogen. It was found that the NH 4 + -N and COD removal efficiencies reached 97.11% and 83.00%, respectively. Besides, the short-term salinity shock of the control, AE1 and AE2 indicated that AE1 and AE2 have better resistance to high salinity when the concentration of NaCl ranged from 1 to 10g/L. Meanwhile, it was found through high-throughput sequencing that bacteria genus Nitrosomonas, Nitrospira and Thauera, which are capable of nitrogen removal, were enriched in the two-staged A/O process. Moreover, both salt-tolerant bacteria and halophili bacteria were also found in the combined process. Therefore, microbial community within the two-staged A/O process could be acclimated to high electrical conductivity, and adapted for electroplating tail wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vertical Tail Buffeting Alleviation Using Piezoelectric Actuators-Some Results of the Actively Controlled Response of Buffet-Affected Tails (ACROBAT) Program

NASA Technical Reports Server (NTRS)

Moses, Robert W.

1997-01-01

Buffet is an aeroelastic phenomenon associated with high performance aircraft especially those with twin vertical tails. In particular, for the F/A-18 aircraft at high angles of attack, vortices emanating from wing/fuselage leading edge extensions burst, immersing the vertical tails in their wake. The resulting buffet loads on the vertical tails are a concern from fatigue and inspection points of view. Recently, a 1/6-scale F-18 wind-tunnel model was tested in the Transonic Dynamics Tunnel at the NASA Langley Research Center as part of the Actively Controlled Response Of Buffet Affected Tails (ACROBAT) Program to assess the use of active controls in reducing vertical tail buffeting. The starboard vertical tail was equipped with an active rudder and the port vertical tail was equipped with piezoelectric actuators. The tunnel conditions were atmospheric air at Mach 0.10. By using single-input-single-output control laws at gains well below the physical limits of the actuators, the power spectral density of the root strains at the frequency of the first bending mode of the vertical tail was reduced by as much as 60 percent up to angles of attack of 37 degrees. Root mean square (RMS) values of root strain were reduced by as much as 19 percent. The results herein illustrate that buffet alleviation of vertical tails can be accomplished using simple active control of the rudder or piezoelectric actuators. In fact, as demonstrated herein, a fixed gain single input single output control law that commands piezoelectric actuators may be active throughout the high angle-of-attack maneuver without requiring any changes during the maneuver. Future tests are mentioned for accentuating the international interest in this area of research.

An Aspergillus aculateus strain was capable of producing agriculturally useful nanoparticles via bioremediation of iron ore tailings.

PubMed

Bedi, Ankita; Singh, Braj Raj; Deshmukh, Sunil K; Adholeya, Alok; Barrow, Colin J

2018-06-01

Mining waste such as iron ore tailing is environmentally hazardous, encouraging researchers to develop effective bioremediation technologies. Among the microbial isolates collected from iron ore tailings, Aspergillus aculeatus (strain T6) showed good leaching efficiency and produced iron-containing nanoparticles under ambient conditions. This strain can convert iron ore tailing waste into agriculturally useful nanoparticles. Fourier-transform Infrared Spectroscopy (FT-IR analysis) established the at the particles are protein coated, with energy dispersive X-ray Spectroscopy (EDX analysis) showing strong signals for iron. Transmission Electron Microscopy (TEM analysis) showed semi-quasi spherical particles having average size of 15 ± 5 nm. These biosynthesized nanoparticles when tested for their efficacy on seed emergence activity of mungbean (Vigna radiata) seeds, and enhanced plant growth at 10 and 20 ppm. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ecological restoration alters microbial communities in mine tailings profiles

NASA Astrophysics Data System (ADS)

Li, Yang; Jia, Zhongjun; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

2016-04-01

Ecological restoration of mine tailings have impact on soil physiochemical properties and microbial communities. The surface soil has been a primary concern in the past decades, however it remains poorly understood about the adaptive response of microbial communities along the profile during ecological restoration of the tailings. In this study, microbial communities along a 60-cm profile were investigated in a mine tailing pond during ecological restoration of the bare waste tailings (BW) with two vegetated soils of Imperata cylindrica (IC) and Chrysopogon zizanioides (CZ) plants. Revegetation of both IC and CZ could retard soil degradation of mine tailing by stimulation of soil pH at 0-30 cm soils and altered the bacterial communities at 0-20 cm depths of the mine tailings. Significant differences existed in the relative abundance of the phyla Alphaproteobacteria, Deltaproteobacteria, Acidobacteria, Firmicutes and Nitrospira. Slight difference of bacterial communities were found at 30-60 cm depths of mine tailings. Abundance and activity analysis of nifH genes also explained the elevated soil nitrogen contents at the surface 0-20 cm of the vegetated soils. These results suggest that microbial succession occurred primarily at surface tailings and vegetation of pioneering plants might have promoted ecological restoration of mine tailings.

Ecological restoration alters microbial communities in mine tailings profiles.

PubMed

Li, Yang; Jia, Zhongjun; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

2016-04-29

Ecological restoration of mine tailings have impact on soil physiochemical properties and microbial communities. The surface soil has been a primary concern in the past decades, however it remains poorly understood about the adaptive response of microbial communities along the profile during ecological restoration of the tailings. In this study, microbial communities along a 60-cm profile were investigated in a mine tailing pond during ecological restoration of the bare waste tailings (BW) with two vegetated soils of Imperata cylindrica (IC) and Chrysopogon zizanioides (CZ) plants. Revegetation of both IC and CZ could retard soil degradation of mine tailing by stimulation of soil pH at 0-30 cm soils and altered the bacterial communities at 0-20 cm depths of the mine tailings. Significant differences existed in the relative abundance of the phyla Alphaproteobacteria, Deltaproteobacteria, Acidobacteria, Firmicutes and Nitrospira. Slight difference of bacterial communities were found at 30-60 cm depths of mine tailings. Abundance and activity analysis of nifH genes also explained the elevated soil nitrogen contents at the surface 0-20 cm of the vegetated soils. These results suggest that microbial succession occurred primarily at surface tailings and vegetation of pioneering plants might have promoted ecological restoration of mine tailings.

Ecological restoration alters microbial communities in mine tailings profiles

PubMed Central

Li, Yang; Jia, Zhongjun; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

2016-01-01

Ecological restoration of mine tailings have impact on soil physiochemical properties and microbial communities. The surface soil has been a primary concern in the past decades, however it remains poorly understood about the adaptive response of microbial communities along the profile during ecological restoration of the tailings. In this study, microbial communities along a 60-cm profile were investigated in a mine tailing pond during ecological restoration of the bare waste tailings (BW) with two vegetated soils of Imperata cylindrica (IC) and Chrysopogon zizanioides (CZ) plants. Revegetation of both IC and CZ could retard soil degradation of mine tailing by stimulation of soil pH at 0–30 cm soils and altered the bacterial communities at 0–20 cm depths of the mine tailings. Significant differences existed in the relative abundance of the phyla Alphaproteobacteria, Deltaproteobacteria, Acidobacteria, Firmicutes and Nitrospira. Slight difference of bacterial communities were found at 30–60 cm depths of mine tailings. Abundance and activity analysis of nifH genes also explained the elevated soil nitrogen contents at the surface 0–20 cm of the vegetated soils. These results suggest that microbial succession occurred primarily at surface tailings and vegetation of pioneering plants might have promoted ecological restoration of mine tailings. PMID:27126064

Influence of cortical synaptic input on striatal neuronal dendritic arborization and sensitivity to excitotoxicity in corticostriatal coculture.

PubMed

Buren, Caodu; Tu, Gaqi; Parsons, Matthew P; Sepers, Marja D; Raymond, Lynn A

2016-08-01

Corticostriatal cocultures are utilized to recapitulate the cortex-striatum connection in vitro as a convenient model to investigate the development, function, and regulation of synapses formed between cortical and striatal neurons. However, optimization of this dissociated neuronal system to more closely reproduce in vivo circuits has not yet been explored. We studied the effect of varying the plating ratio of cortical to striatal neurons on striatal spiny projection neuron (SPN) characteristics in primary neuronal cocultures. Despite the large difference in cortical-striatal neuron ratio (1:1 vs. 1:3) at day of plating, by 18 days in vitro the difference became modest (∼25% lower cortical-striatal neuron ratio in 1:3 cocultures) and the neuronal density was lower in the 1:3 cocultures, indicating enhanced loss of striatal SPNs. Comparing SPNs in cocultures plated at a 1:1 vs. 1:3 ratio, we found that resting membrane potential, input resistance, current injection-induced action potential firing rates, and input-output curves were similar in the two conditions. However, SPNs in the cocultures plated at the lower cortical ratio exhibited reduced membrane capacitance along with significantly shorter total dendritic length, decreased dendritic complexity, and fewer excitatory synapses, consistent with their trend toward reduced miniature excitatory postsynaptic current frequency. Strikingly, the proportion of NMDA receptors found extrasynaptically in recordings from SPNs was significantly higher in the less cortical coculture. Consistently, SPNs in cocultures with reduced cortical input showed decreased basal pro-survival signaling through cAMP response element binding protein and enhanced sensitivity to NMDA-induced apoptosis. Altogether, our study indicates that abundance of cortical input regulates SPN dendritic arborization and survival/death signaling. Copyright © 2016 the American Physiological Society.

A proactive approach to sustainable management of mine tailings

NASA Astrophysics Data System (ADS)

Edraki, Mansour; Baumgartl, Thomas

2015-04-01

The reactive strategies to manage mine tailings i.e. containment of slurries of tailings in tailings storage facilities (TSF's) and remediation of tailings solids or tailings seepage water after the decommissioning of those facilities, can be technically inefficient to eliminate environmental risks (e.g. prevent dispersion of contaminants and catastrophic dam wall failures), pose a long term economic burden for companies, governments and society after mine closure, and often fail to meet community expectations. Most preventive environmental management practices promote proactive integrated approaches to waste management whereby the source of environmental issues are identified to help make a more informed decisions. They often use life cycle assessment to find the "hot spots" of environmental burdens. This kind of approach is often based on generic data and has rarely been used for tailings. Besides, life cycle assessments are less useful for designing operations or simulating changes in the process and consequent environmental outcomes. It is evident that an integrated approach for tailings research linked to better processing options is needed. A literature review revealed that there are only few examples of integrated approaches. The aim of this project is to develop new tailings management models by streamlining orebody characterization, process optimization and rehabilitation. The approach is based on continuous fingerprinting of geochemical processes from orebody to tailings storage facility, and benchmark the success of such proactive initiatives by evidence of no impacts and no future projected impacts on receiving environments. We present an approach for developing such a framework and preliminary results from a case study where combined grinding and flotation models developed using geometallurgical data from the orebody were constructed to predict the properties of tailings produced under various processing scenarios. The modelling scenarios based on the

14 CFR 23.481 - Tail down landing conditions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tail down landing conditions. 23.481 Section 23.481 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Ground Loads § 23.481 Tail down landing conditions. (a) For a tail down landing, the airplane is assumed...

Effect of rare earth Ce on the far infrared radiation property of iron ore tailings ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jie; Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130; Meng, Junping, E-mail: srlj158@sina.com

2015-06-15

Highlights: • Detailed process proposed for preparation of iron ore tailings ceramics. • Replace natural minerals with iron ore tailings as raw materials for preparing functional ceramics. • Impact mechanism of Ce on far infrared ceramics, as well as its optimum addition amounts can be obtained. • Propose a new perspective on considering the mechanism of far infrared radiation. - Abstract: A kind of far infrared radiation ceramics was prepared by using iron ore tailings, CaCO{sub 3} and SiO{sub 2} as main raw materials, and Ce as additive. The result of Fourier transform infrared spectroscopy showed that the sample exhibitsmore » excellent radiation value of 0.914 when doping 7 wt.% Ce. Ce{sup 4+} dissolved into iron diopside and formed interstitial solid solution with it sintered at 1150 °C. The oxidation of Fe{sup 2+} to Fe{sup 3+} caused by Ce{sup 4+} led to a decrease of crystallite sizes and enhancement of Mg–O and Fe–O vibration in iron diopside, which consequently improved the far infrared radiation properties of iron ore tailings ceramics.« less

From lithotroph- to organotroph-dominant: directional shift of microbial community in sulphidic tailings during phytostabilization

PubMed Central

Li, Xiaofang; Bond, Philip L.; Van Nostrand, Joy D.; Zhou, Jizhong; Huang, Longbin

2015-01-01

Engineering microbial diversity to enhance soil functions may improve the success of direct revegetation in sulphidic mine tailings. Therefore, it is essential to explore how remediation and initial plant establishment can alter microbial communities, and, which edaphic factors control these changes under field conditions. A long-term revegetation trial was established at a Pb-Zn-Cu tailings impoundment in northwest Queensland. The control and amended and/or revegetated treatments were sampled from the 3-year-old trial. In total, 24 samples were examined using pyrosequencing of 16S rRNA genes and various chemical properties. The results showed that the microbial diversity was positively controlled by soil soluble Si and negatively controlled by soluble S, total Fe and total As, implying that pyrite weathering posed a substantial stress on microbial development in the tailings. All treatments were dominated by typical extremophiles and lithotrophs, typically Truepera, Thiobacillus, Rubrobacter; significant increases in microbial diversity, biomass and frequency of organotrophic genera (typically Nocardioides and Altererythrobacter) were detected in the revegetated and amended treatment. We concluded that appropriate phytostabilization options have the potential to drive the microbial diversity and community structure in the tailings toward those of natural soils, however, inherent environmental stressors may limit such changes. PMID:26268667

Evaluation Of The Advanced Operating System Of The Ann Arbor Transportation Authority : Transfer And On-Time Performance Study : Before And After AOS Implementation, October 1996 - May 1999

DOT National Transportation Integrated Search

1999-01-01

In 1997, the Ann Arbor (Michigan) Transportation Authority began deploying advanced public transportation systems (APTS) technologies in its fixed route and paratransit operations. The project's concept is the integration of a range of such technolog...

Moth tails divert bat attack: evolution of acoustic deflection.

PubMed

Barber, Jesse R; Leavell, Brian C; Keener, Adam L; Breinholt, Jesse W; Chadwell, Brad A; McClure, Christopher J W; Hill, Geena M; Kawahara, Akito Y

2015-03-03

Adaptations to divert the attacks of visually guided predators have evolved repeatedly in animals. Using high-speed infrared videography, we show that luna moths (Actias luna) generate an acoustic diversion with spinning hindwing tails to deflect echolocating bat attacks away from their body and toward these nonessential appendages. We pit luna moths against big brown bats (Eptesicus fuscus) and demonstrate a survival advantage of ∼ 47% for moths with tails versus those that had their tails removed. The benefit of hindwing tails is equivalent to the advantage conferred to moths by bat-detecting ears. Moth tails lured bat attacks to these wing regions during 55% of interactions between bats and intact luna moths. We analyzed flight kinematics of moths with and without hindwing tails and suggest that tails have a minimal role in flight performance. Using a robust phylogeny, we find that long spatulate tails have independently evolved four times in saturniid moths, further supporting the selective advantage of this anti-bat strategy. Diversionary tactics are perhaps more common than appreciated in predator-prey interactions. Our finding suggests that focusing on the sensory ecologies of key predators will reveal such countermeasures in prey.

Using White-tailed Deer (Odocoileus virginianus) in Infectious Disease Research

PubMed Central

Palmer, Mitchell V; Cox, Rebecca J; Waters, W Ray; Thacker, Tyler C; Whipple, Diana L

2017-01-01

Between 1940 and 2004, more than 335 emerging infectious disease events were reported in the scientific literature. The majority (60%) of these events involved zoonoses, most of which (72%) were of wildlife origin or had an epidemiologically important wildlife host. Because this trend of increasing emerging diseases likely will continue, understanding the pathogenesis, transmission, and diagnosis of these diseases in the relevant wildlife host is paramount. Achieving this goal often requires using wild animals as research subjects, which are vastly different from the traditional livestock or laboratory animals used by most universities and institutions. Using wildlife in infectious disease research presents many challenges but also provides opportunities to answer questions impossible to address by using traditional models. Cervid species, especially white-tailed deer (Odocoileus virginianus), elk (Cervus canadensis), and red deer (Cervus elaphus), are hosts or sentinels for several important pathogens, some of which are zoonotic. The long history of infectious disease research using white-tailed deer, conducted at ever-increasing levels of sophisticated biosecurity, demonstrates that this type of research can be conducted safely and that valuable insights can be gained. The greatest challenges to using wildlife in infectious disease research include animal source, facility design, nutrition, animal handling, and enrichment and other practices that both facilitate animal care and enhance animal wellbeing. The study of Mycobacterium bovis infection in white-tailed deer at the USDA's National Animal Disease Center serves to illustrate one approach to address these challenges. PMID:28724483

Flexible histone tails in a new mesoscopic oligonucleosome model.

PubMed

Arya, Gaurav; Zhang, Qing; Schlick, Tamar

2006-07-01

We describe a new mesoscopic model of oligonucleosomes that incorporates flexible histone tails. The nucleosome cores are modeled using the discrete surface-charge optimization model, which treats the nucleosome as an electrostatic surface represented by hundreds of point charges; the linker DNAs are treated using a discrete elastic chain model; and the histone tails are modeled using a bead/chain hydrodynamic approach as chains of connected beads where each bead represents five protein residues. Appropriate charges and force fields are assigned to each histone chain so as to reproduce the electrostatic potential, structure, and dynamics of the corresponding atomistic histone tails at different salt conditions. The dynamics of resulting oligonucleosomes at different sizes and varying salt concentrations are simulated by Brownian dynamics with complete hydrodynamic interactions. The analyses demonstrate that the new mesoscopic model reproduces experimental results better than its predecessors, which modeled histone tails as rigid entities. In particular, our model with flexible histone tails: correctly accounts for salt-dependent conformational changes in the histone tails; yields the experimentally obtained values of histone-tail mediated core/core attraction energies; and considers the partial shielding of electrostatic repulsion between DNA linkers as a result of the spatial distribution of histone tails. These effects are crucial for regulating chromatin structure but are absent or improperly treated in models with rigid histone tails. The development of this model of oligonucleosomes thus opens new avenues for studying the role of histone tails and their variants in mediating gene expression through modulation of chromatin structure.

From dinosaurs to birds: a tail of evolution

PubMed Central

2014-01-01

A particularly critical event in avian evolution was the transition from long- to short-tailed birds. Primitive bird tails underwent significant alteration, most notably reduction of the number of caudal vertebrae and fusion of the distal caudal vertebrae into an ossified pygostyle. These changes, among others, occurred over a very short evolutionary interval, which brings into focus the underlying mechanisms behind those changes. Despite the wealth of studies delving into avian evolution, virtually nothing is understood about the genetic and developmental events responsible for the emergence of short, fused tails. In this review, we summarize the current understanding of the signaling pathways and morphological events that contribute to tail extension and termination and examine how mutations affecting the genes that control these pathways might influence the evolution of the avian tail. To generate a list of candidate genes that may have been modulated in the transition to short-tailed birds, we analyzed a comprehensive set of mouse mutants. Interestingly, a prevalent pleiotropic effect of mutations that cause fused caudal vertebral bodies (as in the pygostyles of birds) is tail truncation. We identified 23 mutations in this class, and these were primarily restricted to genes involved in axial extension. At least half of the mutations that cause short, fused tails lie in the Notch/Wnt pathway of somite boundary formation or differentiation, leading to changes in somite number or size. Several of the mutations also cause additional bone fusions in the trunk skeleton, reminiscent of those observed in primitive and modern birds. All of our findings were correlated to the fossil record. An open question is whether the relatively sudden appearance of short-tailed birds in the fossil record could be accounted for, at least in part, by the pleiotropic effects generated by a relatively small number of mutational events. PMID:25621146

Unconventional tail configurations for transport aircraft

NASA Astrophysics Data System (ADS)

Sánchez-Carmona, A.; Cuerno-Rejado, C.; García-Hernández, L.

2017-06-01

This article presents the bases of a methodology in order to size unconventional tail configurations for transport aircraft. The case study of this paper is a V-tail con¦guration. Firstly, an aerodynamic study is developed for determining stability derivatives and aerodynamic forces. The objective is to size a tail such as it develops at least the same static stability derivatives than a conventional reference aircraft. The optimum is obtained minimizing its weight. The weight is estimated through two methods: adapted Farrar£s method and a statistical method. The solution reached is heavier than the reference, but it reduces the wetted area.

Exploring Stellar Populations in the Tidal Tails of NGC3256

NASA Astrophysics Data System (ADS)

Rodruck, Michael; Konstantopoulos, Iraklis; Charlton, Jane C.

2015-01-01

Galaxy interactions can inject material into the intergalactic medium via violent gravitational dynamics, often visualized in tidal tails. The composition of these tails has remained a mystery, as previous studies have focused on detecting tidal features, rather than the composite material itself. With this in mind, we have developed an observing program using deep, multiband imaging to probe the chaotic regions of tidal tails in search for an underlying stellar population. NGC3256's Western and Eastern tidal tails serve as a case study for this new technique. Our results show median color values of u - g = 1.12 and r - i = 0.09 for the Western tail, and u - g = 1.29 and r - i = 0.21 for the Eastern tail, corresponding to ages of approximately 450 Myr and 900 Myr for the tails, respectively. A u - g color gradient is seen in the Western tail as well, running from 1.32 to 1.08 (~2000 Myr to 400 Myr), suggesting ages inside tidal tails can have significant variations.

Sirenomelia apus with vestigial tail.

PubMed

Parikh, Tushar B; Nanavati, Ruchi N; Udani, Rekha H

2005-04-01

Sirenomelia is an exceptionally rare congenital malformation characterized by complete or near complete fusion of lower limbs. A newborn with clinical features of sirenomelia including fused lower limbs in medial position, absent fibula, anal atresia, complete absence of urogenital system (bilateral renal agenesis, absent ureters, urinary bladder, absent internal and external genitalia), a single umbilical artery and a vestigial tail is reported. Association of vestigial tail with sirenomelia is not described in the literature.

Interactions regulating the head-to-tail directed assembly of biological Janus rods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greene, A. C.; Bachand, M.; Gomez, A.

We can generalize the directed, head-to-tail self-assembly of microtubule filaments in the context of Janus colloidal rods. Specifically, their assembly at the tens of micron-length scale involves a careful balance between long-range electrostatic repulsion and short-range attractive forces. We show that the addition of counterion salts increases the rate of directed assembly by screening the electrostatic forces and enhancing the effectiveness of short-range interactions at the microtubule ends.

Interactions regulating the head-to-tail directed assembly of biological Janus rods

DOE PAGES

Greene, A. C.; Bachand, M.; Gomez, A.; ...

2017-03-31

We can generalize the directed, head-to-tail self-assembly of microtubule filaments in the context of Janus colloidal rods. Specifically, their assembly at the tens of micron-length scale involves a careful balance between long-range electrostatic repulsion and short-range attractive forces. We show that the addition of counterion salts increases the rate of directed assembly by screening the electrostatic forces and enhancing the effectiveness of short-range interactions at the microtubule ends.

BIOMECHANICS. Why the seahorse tail is square.

PubMed

Porter, Michael M; Adriaens, Dominique; Hatton, Ross L; Meyers, Marc A; McKittrick, Joanna

2015-07-03

Whereas the predominant shapes of most animal tails are cylindrical, seahorse tails are square prisms. Seahorses use their tails as flexible grasping appendages, in spite of a rigid bony armor that fully encases their bodies. We explore the mechanics of two three-dimensional-printed models that mimic either the natural (square prism) or hypothetical (cylindrical) architecture of a seahorse tail to uncover whether or not the square geometry provides any functional advantages. Our results show that the square prism is more resilient when crushed and provides a mechanism for preserving articulatory organization upon extensive bending and twisting, as compared with its cylindrical counterpart. Thus, the square architecture is better than the circular one in the context of two integrated functions: grasping ability and crushing resistance. Copyright © 2015, American Association for the Advancement of Science.

Experiments on a Tail-wheel Shimmy

NASA Technical Reports Server (NTRS)

Harling, R; Dietz, O

1954-01-01

Model tests on the "running belt" and tests with a full-scale tail wheel were made on a rotating drum as well as on a runway in order to investigate the causes of the undesirable shimmy phenomena frequently occurring on airplane tail wheels, and the means of avoiding them. The small model (scale 1:10) permitted simulation of the mass, moments of inertia, and fuselage stiffness of the airplane and determination of their influence on the shimmy, whereas by means of the larger model with pneumatic tires (scale 1:2) more accurate investigations were made on the tail wheel itself. The results of drum and road tests show good agreement with one another and with model values. Detailed investigations were made regarding the dependence of the shimmy tendency on trail, rolling speed, load, size of tires, ground friction,and inclination of the swivel axis; furthermore, regarding the influence of devices with restoring effect on the tail wheel, and the friction damping required for prevention of shimmy. Finally observations from slow-motion pictures are reported and conclusions drawn concerning the influence of tire deformation.

Tail loss and thermoregulation in the common lizard Zootoca vivipara

NASA Astrophysics Data System (ADS)

Herczeg, Gábor; Kovács, Tibor; Tóth, Tamás; Török, János; Korsós, Zoltán; Merilä, Juha

2004-10-01

Tail autotomy in lizards is an adaptive strategy that has evolved to reduce the risk of predation. Since tail loss reduces body mass and moving ability—which in turn are expected to influence thermal balance—there is potential for a trade-off between tail autotomy and thermoregulation. To test this hypothesis, we studied a common lizard (Zootoca vivipara) population at high latitude, inhabiting a high-cost thermal environment. Z. vivipara is a small, non-territorial lizard known as a very accurate thermoregulator. We made two predictions: (1) the reduced body weight due to tail loss results in faster heating rate (a benefit), and (2) the reduction in locomotor ability after tail loss induces a shift to the use of thermally poorer microhabitats (a cost), thus decreasing the field body temperatures of active lizards. We did not find any effect of tail loss on heating rate in laboratory experiments conducted under different thermal conditions. Likewise, no significant relationship between tail condition and field body temperatures, or between tail condition and thermal microhabitat use, were detected. Thus, our results suggest that tail autotomy does not influence the accuracy of thermoregulation in small-bodied lizards.

Tail loss and thermoregulation in the common lizard Zootoca vivipara.

PubMed

Herczeg, Gábor; Kovács, Tibor; Tóth, Tamás; Török, János; Korsós, Zoltán; Merilä, Juha

2004-10-01

Tail autotomy in lizards is an adaptive strategy that has evolved to reduce the risk of predation. Since tail loss reduces body mass and moving ability-which in turn are expected to influence thermal balance-there is potential for a trade-off between tail autotomy and thermoregulation. To test this hypothesis, we studied a common lizard (Zootoca vivipara) population at high latitude, inhabiting a high-cost thermal environment. Z. vivipara is a small, non-territorial lizard known as a very accurate thermoregulator. We made two predictions: (1) the reduced body weight due to tail loss results in faster heating rate (a benefit), and (2) the reduction in locomotor ability after tail loss induces a shift to the use of thermally poorer microhabitats (a cost), thus decreasing the field body temperatures of active lizards. We did not find any effect of tail loss on heating rate in laboratory experiments conducted under different thermal conditions. Likewise, no significant relationship between tail condition and field body temperatures, or between tail condition and thermal microhabitat use, were detected. Thus, our results suggest that tail autotomy does not influence the accuracy of thermoregulation in small-bodied lizards.

Synergistic effects of fire and elephants on arboreal animals in an African savanna.

PubMed

Pringle, Robert M; Kimuyu, Duncan M; Sensenig, Ryan L; Palmer, Todd M; Riginos, Corinna; Veblen, Kari E; Young, Truman P

2015-11-01

Disturbance is a crucial determinant of animal abundance, distribution and community structure in many ecosystems, but the ways in which multiple disturbance types interact remain poorly understood. The effects of multiple-disturbance interactions can be additive, subadditive or super-additive (synergistic). Synergistic effects in particular can accelerate ecological change; thus, characterizing such synergies, the conditions under which they arise, and how long they persist has been identified as a major goal of ecology. We factorially manipulated two principal sources of disturbance in African savannas, fire and elephants, and measured their independent and interactive effects on the numerically dominant vertebrate (the arboreal gekkonid lizard Lygodactylus keniensis) and invertebrate (a guild of symbiotic Acacia ants) animal species in a semi-arid Kenyan savanna. Elephant exclusion alone (minus fire) had negligible effects on gecko density. Fire alone (minus elephants) had negligible effects on gecko density after 4 months, but increased gecko density twofold after 16 months, likely because the decay of fire-damaged woody biomass created refuges and nest sites for geckos. In the presence of elephants, fire increased gecko density nearly threefold within 4 months of the experimental burn; this occurred because fire increased the incidence of elephant damage to trees, which in turn improved microhabitat quality for geckos. However, this synergistic positive effect of fire and elephants attenuated over the ensuing year, such that only the main effect of fire was evident after 16 months. Fire also altered the structure of symbiotic plant-ant assemblages occupying the dominant tree species (Acacia drepanolobium); this influenced gecko habitat selection but did not explain the synergistic effect of fire and elephants. However, fire-driven shifts in plant-ant occupancy may have indirectly mediated this effect by increasing trees' susceptibility to elephant damage. Our

On the folding phenomenon of comet tail rays

NASA Astrophysics Data System (ADS)

Ershkovich, A. I.

1982-01-01

It is shown that the folding phenomenon of the comet tail rays is compatible with the Ferraro isorotation law if the comet tail magnetic field has no azimuthal component, that is, Bphi (the polar angle) equals zero. Considering electric drift due to convectional electric fields, a formula is obtained for the angular rate of a ray closure which reduces to that of Ness and Donn (1966) if the velocity profile across the tail is linear. The magnetic field B of approximately 20-40 gammas in the coma and less than about 10 gammas in the distant tail is estimated under typical solar wind conditions at 1 AU.

Optimization of Plant Growth-Promoting Bacteria-Assisted Phytostabilization of Mine Tailings

PubMed Central

Grandlic, Christopher J.; Palmer, Michael W.; Maier, Raina M.

2009-01-01

Recent studies have indicated that plant growth-promoting bacteria (PGPB) can improve revegetation of arid mine tailings as measured by increased biomass production. The goals of the present study were first to evaluate how mode of application of known PGPB affects plant growth, and second to evaluate the effect of this inoculation on rhizosphere microbial community structure. PGPB application strategies investigated include preliminary surface sterilization of seeds (a common practice in phytoremediation trials) followed by a comparison of two application methods; immersion and alginate encapsulation. Results with two native desert plant species, Atriplex lentiformis and Buchloe dactyloides, suggest that seed surface sterilization prior to inoculation is not necessary to achieve beneficial effects of introduced PGPB. Both PGPB application techniques generally enhanced plant growth although results were both plant and PGPB specific. These results demonstrate that alginate encapsulation, which allows for long-term storage and easier application to seeds, is an effective way to inoculate PGPB. In addition, the influence of PGPB application on B. dactyloides rhizosphere community structure was evaluated using PCR-DGGE (denaturing gradient gel electrophoresis) analysis of bacterial DNA extracted from rhizosphere samples collected 75 d following planting. A comparative analysis of DGGE profiles was performed using canonical correspondence analysis (CCA). DGGE-CCA showed that rhizosphere community profiles from PGPB-inoculated treatments are significantly different from both uninoculated tailings rhizosphere profiles and profiles from the compost used to amend the tailings. Further, community profiles from B. dactyloides inoculated with the best performing PGPB (Arthro mix) were significantly different from two other PGPB tested. These results suggest that introduced PGPB have the potential to influence the development of the rhizosphere community structure found in

A note on trans-Planckian tail effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graef, L.L.; Brandenberger, R., E-mail: leilagraef@usp.br, E-mail: rhb@physics.mcgill.ca

2015-09-01

We study the proposal by Mersini et al. [1] that the observed dark energy might be explained by the back-reaction of the set of tail modes in a theory with a dispersion relation in which the mode frequency decays exponentially in the trans-Planckian regime. The matter tail modes are frozen out, however they induce metric fluctuations. The energy-momentum tensor with which the tail modes effect the background geometry obtains contributions from both metric and matter fluctuations. We calculate the equation of state induced by the tail modes taking into account the gravitational contribution. We find that, in contrast to themore » case of frozen super-Hubble cosmological fluctuations, in this case the matter perturbations dominate, and they yield an equation of state which to leading order takes the form of a positive cosmological constant.« less

Tail mean and related robust solution concepts

NASA Astrophysics Data System (ADS)

Ogryczak, Włodzimierz

2014-01-01

Robust optimisation might be viewed as a multicriteria optimisation problem where objectives correspond to the scenarios although their probabilities are unknown or imprecise. The simplest robust solution concept represents a conservative approach focused on the worst-case scenario results optimisation. A softer concept allows one to optimise the tail mean thus combining performances under multiple worst scenarios. We show that while considering robust models allowing the probabilities to vary only within given intervals, the tail mean represents the robust solution for only upper bounded probabilities. For any arbitrary intervals of probabilities the corresponding robust solution may be expressed by the optimisation of appropriately combined mean and tail mean criteria thus remaining easily implementable with auxiliary linear inequalities. Moreover, we use the tail mean concept to develope linear programming implementable robust solution concepts related to risk averse optimisation criteria.

Species arboreal as a bioindicator of the environmental pollution: Analysis by SR-TXRF

NASA Astrophysics Data System (ADS)

de Vives, Ana Elisa Sirito; Moreira, Silvana; Brienza, Sandra Maria Boscolo; Medeiros, Jean Gabriel S.; Filho, Mario Tomazello; Zucchi, Orghêda Luiza Araújo Domingues; do Nascimento Filho, Virgilio Franco; Barroso, Regina Cely

2007-08-01

This paper aims to study the environmental pollution in the tree development, in order to evaluate its use as bioindicator in urban and countrysides. The sample collection was carried out in Piracicaba city, São Paulo State, that presents high level of environmental contamination in water, soil and air, due to industrial activities, vehicle combustion, sugar-cane leaves burning in the harvesting, etc. The species Caesalpinia peltophoroides ("Sibipiruna") was selected because it is often used in urban arborization. Synchrotron radiation X-ray fluorescence technique (SR-TXRF) was employed to identify and quantify the elements and metals of nutritional and toxicological importance in the wood samples. The analysis was performed in the Brazilian Synchrotron Light Source Laboratory, using a white beam for excitation and an Si(Li) detector for X-ray detection. In several samples were quantified P, K, Ca, Ti, Fe, Sr, Ba and Pb elements.

Adaptive Suction and Blowing for Twin-Tail Buffet Control

NASA Technical Reports Server (NTRS)

Kandil, Osama A.; Yang, Zhi

1999-01-01

Adaptive active flow control for twin-tail buffet alleviation is investigated. The concept behind this technique is to place control ports on the tail outer and inner surfaces with flow suction or blowing applied through these ports in order to minimize the pressure difference across the tail. The suction or blowing volume flow rate from each port is proportional to the pressure difference across the tail at this location. A parametric study of the effects of the number and location of these ports on the buffet response is carried out. The computational model consists of a sharp-edged delta wing of aspect ratio one and swept-back flexible twin tail with taper ratio of 0.23. This complex multidisciplinary problem is solved sequentially using three sets of equations for the fluid flow, aeroelastic response and grid deformation, using a dynamic multi-block grid structure. The computational model is pitched at 30 deg angle of attack. The freestream Mach number and Reynolds number are 0.3 and 1.25 million, respectively. The model is investigated for the inboard position of the twin tails, which corresponds to a separation distance between the twin tails of 33% of the wing span. Comparison of the time history and power spectral density responses of the tails for various distributions of the control ports are presented and discussed.

Structural Conservation of the Myoviridae Phage Tail Sheath Protein Fold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aksyuk, Anastasia A.; Kurochkina, Lidia P.; Fokine, Andrei

2012-02-21

Bacteriophage phiKZ is a giant phage that infects Pseudomonas aeruginosa, a human pathogen. The phiKZ virion consists of a 1450 {angstrom} diameter icosahedral head and a 2000 {angstrom}-long contractile tail. The structure of the whole virus was previously reported, showing that its tail organization in the extended state is similar to the well-studied Myovirus bacteriophage T4 tail. The crystal structure of a tail sheath protein fragment of phiKZ was determined to 2.4 {angstrom} resolution. Furthermore, crystal structures of two prophage tail sheath proteins were determined to 1.9 and 3.3 {angstrom} resolution. Despite low sequence identity between these proteins, all ofmore » these structures have a similar fold. The crystal structure of the phiKZ tail sheath protein has been fitted into cryo-electron-microscopy reconstructions of the extended tail sheath and of a polysheath. The structural rearrangement of the phiKZ tail sheath contraction was found to be similar to that of phage T4.« less

Development in helicopter tail boom strake applications in the US

NASA Technical Reports Server (NTRS)

Wilson, John C.; Kelley, Henry L.; Donahue, Cynthia C.; Yenni, Kenneth R.

1988-01-01

The use of a strake or spoiler on a helicopter tail boom to beneficially change helicopter tail boom air loads was suggested in the United States in 1975. The anticipated benefits were a change of tail boom loads to reduce required tail rotor thrust and power and improve directional control. High tail boom air loads experienced by the YAH-64 and described in 1978 led to a wind tunnel investigation of the usefullness of strakes in altering such loads on the AH-64, UH-60, and UH-1 helicopters. The wind tunnel tests of 2-D cross sections of the tail boom of each demonstrated that a strake or strakes would be effective. Several limited test programs with the U.S. Army's OH-58A, AH-64, and UH-60A were conducted which showed the effects of strakes were modest for those helicopters. The most recent flight test program, with a Bell 204B, disclosed that for the 204B the tail boom strake or strakes would provide more than a modest improvement in directional control and reduction in tail rotor power.

Unstructured 5′-tails act through ribosome standby to override inhibitory structure at ribosome binding sites

PubMed Central

Sterk, Maaike; Romilly, Cédric; Wagner, E Gerhart H

2018-01-01

Abstract Initiation is the rate-limiting step in translation. It is well-known that stable structure at a ribosome binding site (RBS) impedes initiation. The ribosome standby model of de Smit and van Duin, based on studies of the MS2 phage coat cistron, proposed how high translation rates can be reconciled with stable, inhibitory structures at an RBS. Here, we revisited the coat protein system and assessed the translation efficiency from its sequestered RBS by introducing standby mutations. Further experiments with gfp reporter constructs assessed the effects of 5′-tails—as standby sites—with respect to length and sequence contributions. In particular, combining in vivo and in vitro assays, we can show that tails of CA-dinucleotide repeats—and to a lesser extent, AU-repeats—dramatically increase translation rates. Tails of increasing length reach maximal rate-enhancing effects at 16–18 nucleotides. These standby tails are single-stranded and do not exert their effect by structure changes in the neighboring RBS stem–loop. In vitro translation and toeprinting assays furthermore demonstrate that standby effects are exerted at the level of translation initiation. Finally, as expected, destabilizing mutations within the coat RBS indicate an interplay with the effects of standby tails. PMID:29420821

Potential virulence factors of bacteria associated with tail fan necrosis in the spiny lobster, Jasus edwardsii.

PubMed

Zha, H; Jeffs, A; Dong, Y; Lewis, G

2018-05-01

Tail fan necrosis (TFN) is a common condition found in commercially exploited spiny lobsters that greatly diminishes their commercial value. Bacteria possessing proteolytic, chitinolytic and lipolytic capabilities were associated with TFN in spiny lobsters, Jasus edwardsii. In this study, 69 bacterial isolates exhibiting all the three enzymatic capabilities from the haemolymph and tail fans of J. edwardsii with and without TFN were further characterized and compared, including morphology, biofilm formation, antimicrobial activity, antimicrobial resistance, and production of siderophores, melanin and ammonia. The genomic patterns of the most common Vibrio crassostreae isolates were also compared between TFN-affected and unaffected lobsters. Biofilm formation was stronger in bacterial isolates from both haemolymph and tail fans of TFN-affected lobsters compared to those from the unaffected lobsters, while melanin production and siderophore production were stronger in the isolates from tail fans of lobsters with TFN. By contrast, the other characteristics of isolates were similar in lobsters with and without TFN. The Vib. crassostreae isolates from the affected lobsters had similar genomic patterns. Overall, the results indicate that in addition to proteolytic, chitinolytic and lipolytic activities, the bacteria associated with TFN commonly have enhanced activity of important virulence factors, including biofilm formation, melanin production and siderophore production. © 2018 John Wiley & Sons Ltd.

Initiation of soil formation in weathered sulfidic Cu-Pb-Zn tailings under subtropical and semi-arid climatic conditions.

PubMed

You, Fang; Dalal, Ram; Huang, Longbin

2018-08-01

Field evidence has been scarce about soil (or technosol) formation and direct phytostabilization of base metal mine tailings under field conditions. The present study evaluated key attributes of soil formation in weathered and neutral Cu-Pb-Zn tailings subject to organic amendment (WC: woodchips) and colonization of pioneer native plant species (mixed native woody and grass plant species) in a 2.5-year field trial under subtropical and semi-arid climatic conditions. Key soil indicators of engineered soil formation process were characterized, including organic carbon fractions, aggregation, microbial community and key enzymatic activities. The majority (64-87%) of the OC was stabilized in microaggregate or organo-mineral complexes in the amended tailings. The levels of OC and water soluble OC were elevated by 2-3 folds across the treatments, with the highest level in the treatment of WC and plant colonization (WC+P). Specifically, the WC+P treatment increased the proportion of water stable macroaggregates. Plants further contributed to the N rich organic matter in the tailings, favouring organo-mineral interactions and organic stabilization. Besides, the plants played a major role in boosting microbial biomass and activities in the treated tailings. WC and plants enhanced the contents of organic carbon (OC) associated with aggregates (e.g., physically protected OC), formation of water-stable aggregates (e.g., micro and macroaggregates), chemical buffering capacity (e.g., cation exchange capacity). Microbial community and enzymatic activities were also stimulated in the amended tailings. The present results showed that the formation of functional technosol was initiated in the eco-engineered and weathered Cu-Pb-Zn tailings under field conditions for direct phytostabilization. Copyright © 2018 Elsevier Ltd. All rights reserved.

Chronic pharmacological blockade of the Na+ /Ca2+ exchanger modulates the growth and development of the Purkinje cell dendritic arbor in mouse cerebellar slice cultures.

PubMed

Sherkhane, Pradeep; Kapfhammer, Josef P

2017-09-01

The Na + /Ca 2+ exchanger (NCX) is a bidirectional plasma membrane antiporter involved in Ca 2+ homeostasis in eukaryotes. NCX has three isoforms, NCX1-3, and all of them are expressed in the cerebellum. Immunostaining on cerebellar slice cultures indicates that NCX is widely expressed in the cerebellum, including expression in Purkinje cells. The pharmacological blockade of the forward mode of NCX (Ca 2+ efflux mode) by bepridil moderately inhibited growth and development of Purkinje cell dendritic arbor in cerebellar slice cultures. However, the blockade of the reverse mode (Ca 2+ influx mode) by KB-R7943 severely reduced the dendritic arbor and induced a morphological change with thickened distal dendrites. The effect of KB-R7943 on dendritic growth was unrelated to the activity of voltage-gated calcium channels and was also apparent in the absence of bioelectrical activity indicating that it was mediated by NCX expressed in Purkinje cells. We have used additional NCX inhibitors including CB-DMB, ORM-10103, SEA0400, YM-244769, and SN-6 which have higher specificity for NCX isoforms and target either the forward, reverse, or both modes. These inhibitors caused a strong dendritic reduction similar to that seen with KB-R7943, but did not elicit thickening of distal dendrites. Our findings indicate that disturbance of the NCX-dependent calcium transport in Purkinje cells induces a reduction of dendritic arbor, which is presumably caused by changes in the calcium handling, and underline the importance of the calcium equilibrium for the dendritic development in cerebellar Purkinje cells. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

A note on trans-Planckian tail effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graef, L.L.; Instituto de Física, Universidade de São Paulo, Rua do Matão travessa R, São Paulo, SP, 05508-090; Brandenberger, R.

2015-09-09

We study the proposal by Mersini et al. http://dx.doi.org/10.1103/PhysRevD.64.043508 that the observed dark energy might be explained by the back-reaction of the set of tail modes in a theory with a dispersion relation in which the mode frequency decays exponentially in the trans-Planckian regime. The matter tail modes are frozen out, however they induce metric fluctuations. The energy-momentum tensor with which the tail modes effect the background geometry obtains contributions from both metric and matter fluctuations. We calculate the equation of state induced by the tail modes taking into account the gravitational contribution. We find that, in contrast to themore » case of frozen super-Hubble cosmological fluctuations, in this case the matter perturbations dominate, and they yield an equation of state which to leading order takes the form of a positive cosmological constant.« less

Indirect Solar Wind Measurements Using Archival Cometary Tail Observations

NASA Astrophysics Data System (ADS)

Zolotova, Nadezhda; Sizonenko, Yuriy; Vokhmyanin, Mikhail; Veselovsky, Igor

2018-05-01

This paper addresses the problem of the solar wind behaviour during the Maunder minimum. Records on plasma tails of comets can shed light on the physical parameters of the solar wind in the past. We analyse descriptions and drawings of comets between the eleventh and eighteenth century. To distinguish between dust and plasma tails, we address their colour, shape, and orientation. Based on the calculations made by F.A. Bredikhin, we found that cometary tails deviate from the antisolar direction on average by more than 10°, which is typical for dust tails. We also examined the catalogues of Hevelius and Lubieniecki. The first indication of a plasma tail was revealed only for the great comet C/1769 P1.

Role of organic acids in promoting colloidal transport of mercury from mine tailings

USGS Publications Warehouse

Slowey, A.J.; Johnson, S.B.; Rytuba, J.J.; Brown, Gordon E.

2005-01-01

A number of factors affect the transport of dissolved and paniculate mercury (Hg) from inoperative Hg mines, including the presence of organic acids in the rooting zone of vegetated mine waste. We examined the role of the two most common organic acids in soils (oxalic and citric acid) on Hg transport from such waste by pumping a mixed organic acid solution (pH 5.7) at 1 mL/min through Hg mine tailings columns. For the two total organic acid concentrations investigated (20 ??M and 1 mM), particle-associated Hg was mobilized, with the onset of paniculate Hg transport occurring later for the lower organic acid concentration. Chemical analyses of column effluent indicate that 98 wt % of Hg mobilized from the column was paniculate. Hg speciation was determined using extended X-ray absorption fine structure spectroscopy and transmission electron microscopy, showing that HgS minerals are dominant in the mobilized particles. Hg adsorbed to colloids is another likely mode of transport due to the abundance of Fe-(oxyhydr)oxides, Fe-sulfides, alunite, and jarosite in the tailings to which Hg(II) adsorbs. Organic acids produced by plants are likely to enhance the transport of colloid-associated Hg from vegetated Hg mine tailings by dissolving cements to enable colloid release. ?? 2005 American Chemical Society.

14 CFR 23.497 - Supplementary conditions for tail wheels.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Structure Ground Loads § 23.497 Supplementary conditions for tail wheels. In determining the ground loads on the tail wheel and affected supporting structures, the following apply: (a) For the obstruction load, the limit ground reaction obtained in the tail down landing condition is assumed to act up and aft...

14 CFR 23.497 - Supplementary conditions for tail wheels.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Structure Ground Loads § 23.497 Supplementary conditions for tail wheels. In determining the ground loads on the tail wheel and affected supporting structures, the following apply: (a) For the obstruction load, the limit ground reaction obtained in the tail down landing condition is assumed to act up and aft...

14 CFR 29.411 - Ground clearance: tail rotor guard.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground clearance: tail rotor guard. 29.411 Section 29.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... System Loads § 29.411 Ground clearance: tail rotor guard. (a) It must be impossible for the tail rotor to...

14 CFR 27.411 - Ground clearance: tail rotor guard.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground clearance: tail rotor guard. 27.411 Section 27.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... System Loads § 27.411 Ground clearance: tail rotor guard. (a) It must be impossible for the tail rotor to...

14 CFR 27.411 - Ground clearance: tail rotor guard.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ground clearance: tail rotor guard. 27.411 Section 27.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... System Loads § 27.411 Ground clearance: tail rotor guard. (a) It must be impossible for the tail rotor to...

14 CFR 29.411 - Ground clearance: tail rotor guard.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ground clearance: tail rotor guard. 29.411 Section 29.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... System Loads § 29.411 Ground clearance: tail rotor guard. (a) It must be impossible for the tail rotor to...

Thresher sharks use tail-slaps as a hunting strategy.

PubMed

Oliver, Simon P; Turner, John R; Gann, Klemens; Silvosa, Medel; D'Urban Jackson, Tim

2013-01-01

The hunting strategies of pelagic thresher sharks (Alopias pelagicus) were investigated at Pescador Island in the Philippines. It has long been suspected that thresher sharks hunt with their scythe-like tails but the kinematics associated with the behaviour in the wild are poorly understood. From 61 observations recorded by handheld underwater video camera between June and October 2010, 25 thresher shark shunting events were analysed. Thresher sharks employed tail-slaps to debilitate sardines at all times of day. Hunting events comprised preparation, strike, wind-down recovery and prey item collection phases, which occurred sequentially. Preparation phases were significantly longer than the others, presumably to enable a shark to windup a tail-slap. Tail-slaps were initiated by an adduction of the pectoral fins, a manoeuvre that changed a thresher shark's pitch promoting its posterior region to lift rapidly, and stall its approach. Tail-slaps occurred with such force that they may have caused dissolved gas to diffuse out of the water column forming bubbles. Thresher sharks were able to consume more than one sardine at a time, suggesting that tail-slapping is an effective foraging strategy for hunting schooling prey. Pelagic thresher sharks appear to pursue sardines opportunistically by day and night, which may make them vulnerable to fisheries. Alopiids possess specialist pectoral and caudal fins that are likely to have evolved, at least in part, for tail-slapping. The evidence is now clear; thresher sharks really do hunt with their tails.

Thresher Sharks Use Tail-Slaps as a Hunting Strategy

PubMed Central

Oliver, Simon P.; Turner, John R.; Gann, Klemens; Silvosa, Medel; D'Urban Jackson, Tim

2013-01-01

The hunting strategies of pelagic thresher sharks (Alopias pelagicus) were investigated at Pescador Island in the Philippines. It has long been suspected that thresher sharks hunt with their scythe-like tails but the kinematics associated with the behaviour in the wild are poorly understood. From 61 observations recorded by handheld underwater video camera between June and October 2010, 25 thresher shark shunting events were analysed. Thresher sharks employed tail-slaps to debilitate sardines at all times of day. Hunting events comprised preparation, strike, wind-down recovery and prey item collection phases, which occurred sequentially. Preparation phases were significantly longer than the others, presumably to enable a shark to windup a tail-slap. Tail-slaps were initiated by an adduction of the pectoral fins, a manoeuvre that changed a thresher shark's pitch promoting its posterior region to lift rapidly, and stall its approach. Tail-slaps occurred with such force that they may have caused dissolved gas to diffuse out of the water column forming bubbles. Thresher sharks were able to consume more than one sardine at a time, suggesting that tail-slapping is an effective foraging strategy for hunting schooling prey. Pelagic thresher sharks appear to pursue sardines opportunistically by day and night, which may make them vulnerable to fisheries. Alopiids possess specialist pectoral and caudal fins that are likely to have evolved, at least in part, for tail-slapping. The evidence is now clear; thresher sharks really do hunt with their tails. PMID:23874415

Hybird state of the tail mangetic configuration during steady convection events

NASA Technical Reports Server (NTRS)

Sergeev, V. A.; Pulkkinen, T. I.; Pellinen, T. I.; Tsyganenko, N. A.

1994-01-01

Previous observations have shown that during periods of steady magnetospheric convection (SMC) a large amount of magnetic flux crosses the plasma sheet (corresponding to approximately 10 deg wide auroral oval at the nightside) and that the magnetic configuration in the midtail is relaxed (the curent sheet is thick and contains enhanced B(sub Z). These signatures are typical for the substorm recovery phase. Using near-geostationary magnetic field data, magnetic field modeling and a noval diagostic technique (isotropic boundary algorithm), we show that in the near-Earth tail the magnetic confirguration is very stretched during the SMC events. This stretching is caused by an intense, thin westward current. Because of the srongly depressed B(sub Z), there is a large radial gradient in the near-tail magetic field. These signatures have been peviously associated only with the substorm growth phase. Our results indicate that during the SMC periods the magnetic configuration is very peculiar, with co-existing thin near-Earth current sheet and thick midtail plasma sheet. The deep local minimum of the equatorial B(sub Z) that devleops at R approximately 12 R(sub E) is consistent with steady, adiabatic, Earthward convection in the midtail. These results impose contraints on the existing substorm theories, and call for an explanation of how such a stressed configuration can persist for such a long time without tail current disruptions that occur at the end of a substorm growth phase.

A Tale of Two Tails: Not Just Skin Deep

PubMed Central

Dutta, Abhijit; Ghosh, Sudip Kumar; Mandal, Asok Kumar

2015-01-01

The dorsal cutaneous appendage or the so called human tail is a rare congenital anomaly protruding from the lumbo-sacro-coccygeal area. These caudal appendages are divided into true-tails and pseudo-tails. We report here two cases of congenital pseudo-tail with underlying spina bifida and lipo-meningocele. In this article we seek to emphasize that, as the skin and nervous systems are intimately linked by their similar ectodermal origin, a dorsal appendage may be regarded as a cutaneous marker of the underlying spinal dysraphism. PMID:26288414

Evaluation of the environmental plasticity in the xerohalophyte Zygophyllum fabago L. for the phytomanagement of mine tailings in semiarid areas.

PubMed

Párraga-Aguado, I; González-Alcaraz, M N; López-Orenes, A; Ferrer-Ayala, M A; Conesa, H M

2016-10-01

Phytomanagement by phytostabilisation of metal(loid)-enriched mine tailings in semiarid areas has been proposed as a suitable technique to promote a self-sustainable vegetal cover for decreasing the spread of polluted particles by erosion. The goal of this work was to evaluate the contribution of a pioneer plant species (Zygophyllum fabago) in ameliorating the soil conditions at two mine tailings piles located in a semiarid area in Southeast Spain. The ecophysiological performance of this plant species compared to a control population was assessed by analysing the nutritional and ecophysiological status. The presence of Z. fabago in mine tailings enhanced the soil microbial activity and increased the content of soil organic carbon within the rhizosphere (approx. 50% increasing). Metal(loid) concentrations in the tailings may play a minor role in the establishment of Z. fabago plants due to the low metal(loid) availability in the tailings (low CaCl2-extractable concentrations) and low uptake in the plants (e.g. up to 300 mg kg(-1) Zn in leaves). The lower δ13C and δ18O in the plants sampled at both tailings compared to the control ones may indicate softer stomatal regulation in relation to the control site plants and therefore lower WUE [corrected]. The Z. fabago plants may skip some energy-demanding mechanisms such as stomatal control and/or proline synthesis to overcome the environmental stresses posed at the tailings. The Z. fabago plants revealed high plasticity of the species for adapting to the low fertility soil conditions of the tailings and to overcome constraints associated to the dry season. Copyright © 2016 Elsevier Ltd. All rights reserved.

A potential role for bat tail membranes in flight control.

PubMed

Gardiner, James D; Dimitriadis, Grigorios; Codd, Jonathan R; Nudds, Robert L

2011-03-30

Wind tunnel tests conducted on a model based on the long-eared bat Plecotus auritus indicated that the positioning of the tail membrane (uropatagium) can significantly influence flight control. Adjusting tail position by increasing the angle of the legs ventrally relative to the body has a two-fold effect; increasing leg-induced wing camber (i.e., locally increased camber of the inner wing surface) and increasing the angle of attack of the tail membrane. We also used our model to examine the effects of flying with and without a tail membrane. For the bat model with a tail membrane increasing leg angle increased the lift, drag and pitching moment (nose-down) produced. However, removing the tail membrane significantly reduced the change in pitching moment with increasing leg angle, but it had no significant effect on the level of lift produced. The drag on the model also significantly increased with the removal of the tail membrane. The tail membrane, therefore, is potentially important for controlling the level of pitching moment produced by bats and an aid to flight control, specifically improving agility and manoeuvrability. Although the tail of bats is different from that of birds, in that it is only divided from the wings by the legs, it nonetheless, may, in addition to its prey capturing function, fulfil a similar role in aiding flight control.

A Potential Role for Bat Tail Membranes in Flight Control

PubMed Central

Gardiner, James D.; Dimitriadis, Grigorios; Codd, Jonathan R.; Nudds, Robert L.

2011-01-01

Wind tunnel tests conducted on a model based on the long-eared bat Plecotus auritus indicated that the positioning of the tail membrane (uropatagium) can significantly influence flight control. Adjusting tail position by increasing the angle of the legs ventrally relative to the body has a two-fold effect; increasing leg-induced wing camber (i.e., locally increased camber of the inner wing surface) and increasing the angle of attack of the tail membrane. We also used our model to examine the effects of flying with and without a tail membrane. For the bat model with a tail membrane increasing leg angle increased the lift, drag and pitching moment (nose-down) produced. However, removing the tail membrane significantly reduced the change in pitching moment with increasing leg angle, but it had no significant effect on the level of lift produced. The drag on the model also significantly increased with the removal of the tail membrane. The tail membrane, therefore, is potentially important for controlling the level of pitching moment produced by bats and an aid to flight control, specifically improving agility and manoeuvrability. Although the tail of bats is different from that of birds, in that it is only divided from the wings by the legs, it nonetheless, may, in addition to its prey capturing function, fulfil a similar role in aiding flight control. PMID:21479137

Arboreal adaptations of body fat in wild toque macaques (Macaca sinica) and the evolution of adiposity in primates.

PubMed

Dittus, Wolfgang P J

2013-11-01

There is a paucity of information on body composition and fat patterning in wild nonhuman primates. Dissected adipose tissue from wild toque macaques (Macaca sinica) (WTM), feeding on a natural diet, accounted for 2.1% of body weight. This was far less than fatness reported for nonhuman primates raised in captivity or for contemporary humans. In WTM, fatness increased with age and diet richness, but did not differ by sex. In WTM (none of which were obese) intra-abdominal fat filled first, and "excess" fat was stored peripherally in a ratio of about 6:1. Intermuscular fat was minimal (0.1%). The superficial paunch held <15% of subcutaneous fat weight in contrast to its much larger proportions in obese humans and captive monkeys where most added fat accumulates subcutaneously. With increasing total adiposity, accumulating fat shifted in its distribution among eight different main internal and peripheral deposit areas-consistent with maintaining body balance and a low center of gravity. The available data suggest that, in arboreal primates, adaptations for agile locomotion and terminal branch feeding set constraints on the quantity and distribution of fat. The absence of a higher percentage of body fat in females and neonates (as are typical of humans) suggests that arboreal adaptations preclude the development of fat-dependent, large-brained infants and the adipose-rich mothers needed to sustain them. The lifestyle and body composition of wild primates represent a more appropriate model for early human foragers than well-fed captive monkeys do. Copyright © 2013 Wiley Periodicals, Inc.

Enhancement factor statistics of surface enhanced Raman scattering in multiscale heterostructures of nanoparticles.

PubMed

Zito, Gianluigi; Rusciano, Giulia; Sasso, Antonio

2016-08-07

Suitable metal nanostructures may induce surface-enhanced Raman scattering (SERS) enhancement factors (EFs) large-enough to reach single-molecule sensitivity. However, the gap hot-spot EF probability density function (PDF) has the character of a long-tail distribution, which dramatically mines the reproducibility of SERS experiments. Herein, we carry out electrodynamic calculations based on a 3D finite element method of two plasmonic nanostructures, combined with Monte Carlo simulations of the EF statistics under different external conditions. We compare the PDF produced by a homodimer of nanoparticles with that provided by a self-similar trimer. We show that the PDF is sensitive to the spatial distribution of near-field enhancement specifically supported by the nanostructure geometry. Breaking the symmetry of the plasmonic system is responsible for inducing particular modulations of the PDF tail resembling a multiple Poisson distribution. We also study the influence that molecular diffusion towards the hottest hot-spot, or selective hot-spot targeting, might have on the EF PDF. Our results quantitatively assess the possibility of designing the response of a SERS substrate so as to contain the intrinsic EF PDF variance and significantly improving, in principle, the reproducibility of SERS experiments.

Vertical Tail Buffeting Alleviation Using Piezoelectric Actuators: Some Results of the Actively Controlled Response of Buffet-Affected Tails (ACROBAT) Program

NASA Technical Reports Server (NTRS)

Moses, Robert W.

1997-01-01

A 1/6-scale F-18 wind-tunnel model was tested in the Transonic Dynamics Tunnel at the NASA Langley Research Center as part of the Actively Controlled Response Of Buffet Affected Tails (ACROBAT) program to assess the use of active controls in reducing vertical tail buffeting. The starboard vertical tail was equipped with an active rudder and the port vertical tail was equipped with piezoelectric actuators. The tunnel conditions were atmospheric air at a dynamic pressure of 14 psf. By using single-input-single-output control laws at gains well below the physical limits of the actuators, the power spectral density of the root strains at the frequency of the first bending mode of the vertical tail was reduced by as much as 60 percent up to angles of attack of 37 degrees. Root mean square (RMS) values of root strain were reduced by as much as 19 percent. Buffeting alleviation results when using the rudder are presented for comparison. Stability margins indicate that a constant gain setting in the control law may be used throughout the range of angle of attack tested.

Radon emanation from backfilled mill tailings in underground uranium mine.

PubMed

Sahu, Patitapaban; Mishra, Devi Prasad; Panigrahi, Durga Charan; Jha, Vivekananda; Patnaik, R Lokeswara; Sethy, Narendra Kumar

2014-04-01

Coarser mill tailings used as backfill to stabilize the stoped out areas in underground uranium mines is a potential source of radon contamination. This paper presents the quantitative assessment of radon emanation from the backfilled tailings in Jaduguda mine, India using a cylindrical accumulator. Some of the important parameters such as (226)Ra activity concentration, bulk density, bulk porosity, moisture content and radon emanation factor of the tailings affecting radon emanation were determined in the laboratory. The study revealed that the radon emanation rate of the tailings varied in the range of 0.12-7.03 Bq m(-2) s(-1) with geometric mean of 1.01 Bq m(-2) s(-1) and geometric standard deviation of 3.39. An increase in radon emanation rate was noticed up to a moisture saturation of 0.09 in the tailings, after which the emanation rate gradually started declining with saturation due to low diffusion coefficient of radon in the saturated tailings. Radon emanation factor of the tailings varied in the range of 0.08-0.23 with the mean value of 0.21. The emanation factor of the tailings with moisture saturation level over 0.09 was found to be about three times higher than that of the absolutely dry tailings. The empirical relationship obtained between (222)Rn emanation rate and (226)Ra activity concentration of the tailings indicated a significant positive linear correlation (r = 0.95, p < 0.001). This relationship may be useful for quick prediction of radon emanation rate from the backfill material of similar nature. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of Configuration Pitching Motion on Twin Tail Buffet Response

NASA Technical Reports Server (NTRS)

Sheta, Essam F.; Kandil, Osama A.

1998-01-01

The effect of dynamic pitch-up motion of delta wing on twin-tail buffet response is investigated. The computational model consists of a delta wing-twin tail configuration. The computations are carried out on a dynamic multi-block grid structure. This multidisciplinary problem is solved using three sets of equations which consists of the unsteady Navier-Stokes equations, the aeroelastic equations, and the grid displacement equations. The configuration is pitched-up from zero up to 60 deg. angle of attack, and the freestream Mach number and Reynolds number are 0.3 and 1.25 million, respectively. With the twin tail fixed as rigid surfaces and with no-forced pitch-up motion, the problem is solved for the initial flow conditions. Next, the problem is solved for the twin-tail response for uncoupled bending and torsional vibrations due to the unsteady loads on the twin tail and due to the forced pitch-up motion. The dynamic pitch-up problem is also solved for the flow response with the twin tail kept rigid. The configuration is investigated for inboard position of the twin tail which corresponds to a separation distance between the twin tail of 33% wing chord. The computed results are compared with the available experimental data.

Tail regeneration affects the digestive performance of a Mediterranean lizard

NASA Astrophysics Data System (ADS)

Sagonas, Kostas; Karambotsi, Niki; Bletsa, Aristoula; Reppa, Aikaterini; Pafilis, Panayiotis; Valakos, Efstratios D.

2017-04-01

In caudal autotomy, lizards shed their tail to escape from an attacking predator. Since the tail serves multiple functions, caudal regeneration is of pivotal importance. However, it is a demanding procedure that requires substantial energy and nutrients. Therefore, lizards have to increase energy income to fuel the extraordinary requirements of the regenerating tail. We presumed that autotomized lizards would adjust their digestion to acquire this additional energy. To clarify the effects of tail regeneration on digestion, we compared the digestive performance before autotomy, during regeneration, and after its completion. Tail regeneration indeed increased gut passage time but did not affect digestive performance in a uniform pattern: though protein income was maximized, lipid and sugar acquisition remained stable. This divergence in proteins may be attributed to their particular role in tail reconstruction, as they are the main building blocks for tissue formation.

Nano-scale mechanisms of metal rhizostabilization in mine tailings

NASA Astrophysics Data System (ADS)

Chorover, J.; Rushforth, R. R.; Hayes, S.; Root, R.; Maier, R.

2010-12-01

Desert mine tailings pose significant health risks to proximal communities and ecosystems because metal-laden particles in the un-vegetated landscapes are readily transported via wind and water erosion. Therefore, establishment of a bioactive, vegetated cover and associated root mass can contribute significantly to site remediation. As a result of delivery to the subsurface of labile forms of reduced carbon, the incipient rhizosphere presents a bioactive zone where geochemical disequilibria are strongly influenced by root-microbe-metal-mineral interactions. Infusion of biota and carbon affect local mineral transformations and the associated speciation of toxic metal(loid)s. We investigated biogeochemical transformations in Pb and Zn containing mine tailings from Klondyke State Superfund site (AZ) as affected by phytostabilization. The research approach was to combine instrumented column experiments with molecular spectroscopy of the solid phase. Pb LIII-edge and Zn K-edge EXAFS spectroscopy, synchrotron-based XRF and XRD, and Raman microspectroscopy were employed to assess local coordination and mineralogy of Pb and Zn. Prior to plant introduction, contaminant Pb in the weathered surficial tailings was dominantly present in the minerals plumbojarosite (PbFe6(SO4)4(OH)12) and PbSO4, whereas Zn was dominantly present as hemimorphite (Zn4Si2O7(OH)2.H2O), Zn phyllosilicate, and ZnSO4(s). Column experiments showed that planted columns diminished pore water and effluent concentrations of both Pb and Zn, whereas transport of some other metals (e.g., Cu) was enhanced by complexation with dissolved organic matter. Spectroscopic studies of fine root tissues and root-microbe-metal associations revealed the formation of apparently biogenic Mn oxide plaques that were highly enriched in Zn and Pb.

Orphan Stars Found in Long Galaxy Tail

NASA Astrophysics Data System (ADS)

2007-09-01

Astronomers have found evidence that stars have been forming in a long tail of gas that extends well outside its parent galaxy. This discovery suggests that such "orphan" stars may be much more prevalent than previously thought. The comet-like tail was observed in X-ray light with NASA's Chandra X-ray Observatory and in optical light with the Southern Astrophysical Research (SOAR) telescope in Chile. The feature extends for more than 200,000 light years and was created as gas was stripped from a galaxy called ESO 137-001 that is plunging toward the center of Abell 3627, a giant cluster of galaxies. "This is one of the longest tails like this we have ever seen," said Ming Sun of Michigan State University, who led the study. "And, it turns out that this is a giant wake of creation, not of destruction." Chandra X-ray Image of ESO 137-001 and Tail in Abell 3627 Chandra X-ray Image of ESO 137-001 and Tail in Abell 3627 The observations indicate that the gas in the tail has formed millions of stars. Because the large amounts of gas and dust needed to form stars are typically found only within galaxies, astronomers have previously thought it unlikely that large numbers of stars would form outside a galaxy. "This isn't the first time that stars have been seen to form between galaxies," said team member Megan Donahue, also of MSU. "But the number of stars forming here is unprecedented." The evidence for star formation in this tail includes 29 regions of ionized hydrogen glowing in optical light, thought to be from newly formed stars. These regions are all downstream of the galaxy, located in or near the tail. Two Chandra X-ray sources are near these regions, another indication of star formation activity. The researchers believe the orphan stars formed within the last 10 million years or so. The stars in the tail of this fast-moving galaxy, which is some 220 million light years away, would be much more isolated than the vast majority of stars in galaxies. H-alpha Image of

Cell lineage tracing during Xenopus tail regeneration.

PubMed

Gargioli, Cesare; Slack, Jonathan M W

2004-06-01

The tail of the Xenopus tadpole will regenerate following amputation, and all three of the main axial structures - the spinal cord, the notochord and the segmented myotomes - are found in the regenerated tail. We have investigated the cellular origin of each of these three tissue types during regeneration. We produced Xenopus laevis embryos transgenic for the CMV (Simian Cytomegalovirus) promoter driving GFP (Green Fluorescent Protein) ubiquitously throughout the embryo. Single tissues were then specifically labelled by making grafts at the neurula stage from transgenic donors to unlabelled hosts. When the hosts have developed to tadpoles, they carry a region of the appropriate tissue labelled with GFP. These tails were amputated through the labelled region and the distribution of labelled cells in the regenerate was followed. We also labelled myofibres using the Cre-lox method. The results show that the spinal cord and the notochord regenerate from the same tissue type in the stump, with no labelling of other tissues. In the case of the muscle, we show that the myofibres of the regenerate arise from satellite cells and not from the pre-existing myofibres. This shows that metaplasia between differentiated cell types does not occur, and that the process of Xenopus tail regeneration is more akin to tissue renewal in mammals than to urodele tail regeneration.

Predicting arsenic concentrations in porewaters of buried uranium mill tailings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langmuir, D.; Mahoney, J.; MacDonald, A.

The proposed JEB Tailings Management Facility (TMF) to be emplaced below the groundwater table in northern Saskatchewan, Canada, will contain uranium mill tailings from McClean Lake, Midwest and Cigar Lake ore bodies, which are high in arsenic (up to 10%) and nickel (up to 5%). A serious concern is the possibility that high arsenic and nickel concentrations may be released from the buried tailings, contaminating adjacent groundwaters and a nearby lake. Laboratory tests and geochemical modeling were performed to examine ways to reduce the arsenic and nickel concentrations in TMF porewaters so as to minimize such contamination from tailings buriedmore » for 50 years and longer. The tests were designed to mimic conditions in the mill neutralization circuit (3 hr tests at 25 C), and in the TMF after burial (5--49 day aging tests). The aging tests were run at 50, 25 and 4 C (the temperature in the TMF). In order to optimize the removal of arsenic by adsorption and precipitation, ferric sulfate was added to tailings raffinates having Fe/As ratios of less than 3--5. The acid raffinates were then neutralized by addition of slaked lime to nominal pH values of 7, 8, or 9. Analysis and modeling of the test results showed that with slaked lime addition to acid tailings raffinates, relatively amorphous scorodite (ferric arsenate) precipitates near pH 1, and is the dominant form of arsenate in slake limed tailings solids except those high in Ni and As and low in Fe, in which cabrerite-annabergite (Ni, Mg, Fe(II) arsenate) may also precipitate near pH 5--6. In addition to the arsenate precipitates, smaller amounts of arsenate are also adsorbed onto tailings solids. The aging tests showed that after burial of the tailings, arsenic concentrations may increase with time from the breakdown of the arsenate phases (chiefly scorodite). However, the tests indicate that the rate of change decreases and approaches zero after 72 hrs at 25 C, and may equal zero at all times in the TMF at 4

Particular geoscientific perspectives on stable isotope analysis in the arboreal system

NASA Astrophysics Data System (ADS)

Helle, Gerhard; Balting, Daniel; Pauly, Maren; Slotta, Franziska

2017-04-01

In geosciences stable isotopes of carbon, oxygen and hydrogen from the tree ring archive have been used for several decades to trace the course of past environmental and climatological fluctuations. In contrast to ice cores, the tree ring archive is of biological nature (like many other terrestrial archives), but provides the opportunity to establish site networks with very high resolution in space and time. Many of the basic physical mechanisms of isotope shifts are known, but biologically mediated processes may lead to isotope effects that are poorly understood. This implies that the many processes within the arboreal system leading to archived isotope ratios in wood material are governed by a multitude of environmental variables that are not only tied to the isotopic composition of atmospheric source values (precipitation, CO2), but also to seasonally changing metabolic flux rates and pool sizes of photosynthates within the trees. Consequently, the extraction of climate and environmental information is particularly challenging and reconstructions are still of rather qualitative nature. Over the last 10 years or so, monitoring studies have been implemented to investigate stable isotope, climate and environmental signal transfer within the arboreal system to develop transfer or response functions that can translate the relevant isotope values extracted from tree rings into climate or other environmental variables. To what extent have these efforts lead to a better understanding that helps improving the meaningfulness of tree ring isotope signals? For example, do monitoring studies help deciphering the causes for age-related trends in tree ring stable isotope sequences that are published in a growing number of papers. Are existing monitoring studies going into detail enough or is it already too much effort for the outcome? Based on what we know already particularly in mesic habitats, tree ring stable isotopes are much better climate proxies than other tree ring

The interaction of HMGB1 and linker histones occurs through their acidic and basic tails.

PubMed

Cato, Laura; Stott, Katherine; Watson, Matthew; Thomas, Jean O

2008-12-31

H1 and HMGB1 bind to linker DNA in chromatin, in the vicinity of the nucleosome dyad. They appear to have opposing effects on the nucleosome, H1 stabilising it by "sealing" two turns of DNA around the octamer, and HMGB1 destabilising it, probably by bending the adjacent DNA. Their presence in chromatin might be mutually exclusive. Displacement/replacement of one by the other as a result of their highly dynamic binding in vivo might, in principle, involve interactions between them. Chemical cross-linking and gel-filtration show that a 1:1 linker histone/HMGB1 complex is formed, which persists at physiological ionic strength, and that complex formation requires the acidic tail of HMGB1. NMR spectroscopy shows that the linker histone binds, predominantly through its basic C-terminal domain, to the acidic tail of HMGB1, thereby disrupting the interaction of the tail with the DNA-binding faces of the HMG boxes. A potential consequence of this interaction is enhanced DNA binding by HMGB1, and concomitantly lowered affinity of H1 for DNA. In a chromatin context, this might facilitate displacement of H1 by HMGB1.

PSR J0357+3205: THE TAIL OF THE TURTLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marelli, M.; De Luca, A.; Salvetti, D.

2013-03-01

Using a new XMM-Newton observation, we have characterized the X-ray properties of the middle-aged radio-quiet {gamma}-ray pulsar J0357+3205 (named Morla) and its tail. The X-ray emission from the pulsar is consistent with a magnetospheric non-thermal origin plus a thermal emission from a hot spot (or hot spots). The lack of a thermal component from the whole surface makes Morla the coldest neutron star in its age range. We found marginal evidence for a double-peaked modulation of the X-ray emission. The study of the 9' long tail confirmed the lack of extended emission near the pulsar itself. The tail shows amore » very asymmetric brightness profile and its spectrum lacks any spatial variation. We found the nebular emission to be inconsistent with a classical bow shock, ram-pressure-dominated pulsar wind nebula. We propose thermal bremsstrahlung as an alternative mechanism for Morla's tail emission. In this scenario, the tail emission comes from the shocked interstellar medium (ISM) material heated up to X-ray temperatures. This can fully explain the peculiar features of the tail, assuming a hot, moderately dense ISM around the pulsar. For a bremsstrahlung-emitting tail, we can estimate the pulsar distance to be between 300 and 900 pc. A pulsar velocity of {approx}1900 km s{sup -1} is required, which would make Morla the pulsar with the largest velocity, and high inclination angles (>70 Degree-Sign ) are preferred. We propose Morla's nebula as the first example of a new 'turtle's tail' class of thermally emitting nebulae associated with high-velocity pulsars.« less

The tails of the satellite auroral footprints at Jupiter

NASA Astrophysics Data System (ADS)

Bonfond, B.; Saur, J.; Grodent, D.; Badman, S. V.; Bisikalo, D.; Shematovich, V.; Gérard, J.-C.; Radioti, A.

2017-08-01

The electromagnetic interaction between Io, Europa, and Ganymede and the rotating plasma that surrounds Jupiter has a signature in the aurora of the planet. This signature, called the satellite footprint, takes the form of a series of spots located slightly downstream of the feet of the field lines passing through the moon under consideration. In the case of Io, these spots are also followed by an extended tail in the downstream direction relative to the plasma flow encountering the moon. A few examples of a tail for the Europa footprint have also been reported in the northern hemisphere. Here we present a simplified Alfvénic model for footprint tails and simulations of vertical brightness profiles for various electron distributions, which favor such a model over quasi-static models. We also report here additional cases of Europa footprint tails, in both hemispheres, even though such detections are rare and difficult. Furthermore, we show that the Ganymede footprint can also be followed by a similar tail. Finally, we present a case of a 320° long Io footprint tail, while other cases in similar configurations do not display such a length.

Structural basis of molecular recognition of helical histone H3 tail by PHD finger domains.

PubMed

Bortoluzzi, Alessio; Amato, Anastasia; Lucas, Xavier; Blank, Manuel; Ciulli, Alessio

2017-05-04

The plant homeodomain (PHD) fingers are among the largest family of epigenetic domains, first characterized as readers of methylated H3K4. Readout of histone post-translational modifications by PHDs has been the subject of intense investigation; however, less is known about the recognition of secondary structure features within the histone tail itself. We solved the crystal structure of the PHD finger of the bromodomain adjacent to zinc finger 2A [BAZ2A, also known as TIP5 (TTF-I/interacting protein 5)] in complex with unmodified N-terminal histone H3 tail. The peptide is bound in a helical folded-back conformation after K4, induced by an acidic patch on the protein surface that prevents peptide binding in an extended conformation. Structural bioinformatics analyses identify a conserved Asp/Glu residue that we name 'acidic wall', found to be mutually exclusive with the conserved Trp for K4Me recognition. Neutralization or inversion of the charges at the acidic wall patch in BAZ2A, and homologous BAZ2B, weakened H3 binding. We identify simple mutations on H3 that strikingly enhance or reduce binding, as a result of their stabilization or destabilization of H3 helicity. Our work unravels the structural basis for binding of the helical H3 tail by PHD fingers and suggests that molecular recognition of secondary structure motifs within histone tails could represent an additional layer of regulation in epigenetic processes. © 2017 The Author(s).

Hydrodynamic Characteristics of a Low-drag, Planing-tail Flying-boat Hull

NASA Technical Reports Server (NTRS)

Suydam, Henry B

1948-01-01

The hydrodynamic characteristics of a flying-boat incorporating a low-drag, planing-tail hull were determined from model tests made in Langley tank number 2 and compared with tests of the same flying boat incorporating a conventional-type hull. The planing-tail model, with which stable take-offs were possible for a large range of elevator positions at all center-of-gravity locations tested, had more take-off stability than the conventional model. No upper-limit porpoising was encountered by the planing-tail model. The maximum changes in rise during landings were lower for the planing-tail model than for the conventional model at most contact trims, an indication of improved landing stability for the planing-tail model. The hydrodynamic resistance of the planing-tail hull was lower than the conventional hull at all speeds, and the load-resistance ratio was higher for the planing-tail hull, being especially high at the hump. The static trim of the planing-tail hull was much higher than the conventional hull, but the variation of trim with speed during take-off was smaller.

Heavy-tailed fractional Pearson diffusions.

PubMed

Leonenko, N N; Papić, I; Sikorskii, A; Šuvak, N

2017-11-01

We define heavy-tailed fractional reciprocal gamma and Fisher-Snedecor diffusions by a non-Markovian time change in the corresponding Pearson diffusions. Pearson diffusions are governed by the backward Kolmogorov equations with space-varying polynomial coefficients and are widely used in applications. The corresponding fractional reciprocal gamma and Fisher-Snedecor diffusions are governed by the fractional backward Kolmogorov equations and have heavy-tailed marginal distributions in the steady state. We derive the explicit expressions for the transition densities of the fractional reciprocal gamma and Fisher-Snedecor diffusions and strong solutions of the associated Cauchy problems for the fractional backward Kolmogorov equation.

Hydrogen-bond rich ionic liquids with hydroxyl cationic tails

NASA Astrophysics Data System (ADS)

Deng, Li; Shi, Rui; Wang, Yanting; Ou-Yang, Zhong-Can

2013-02-01

To investigate if the amphiphilic feature exhibited in ionic liquids (ILs) with nonpolar cationic tails still exists in ILs with polar tails, by performing molecular dynamics simulations for 1-(8-hydroxyoctyl)-3-methyl-imidazolium nitrate (COH) and 1-octyl-3-methyl-imidazolium nitrate (C8), we found that, in COH, cationic tail groups can no longer aggregate to form separated nonpolar tail domains, instead hydroxyl groups form a rich number of hydrogen bonds with other groups, indicating that the hydroxyl substituent changes the IL system from an amphiphilic liquid to a polar liquid. Due to the large amount of hydrogen bonds, COH has slower dynamics than C8.

Effectiveness of Flow Control for Alleviation of Twin-Tail Buffet

NASA Technical Reports Server (NTRS)

Sheta, Essam F.; Kandil, Osama A.; Yang, Zhi

1998-01-01

Effectiveness of active flow control for twin- tail buffet alleviation is investigated. Tangen- tial leading-edge blowing (TLEB) and flow suction along the vortex cores (FSVC) of the lead- ing edges of the delta wing are used to delay the vortex breakdown flow upstream of the twin tail. The combined effect of the TLEB and FSVC is also investigated. A parametric study of the effects of the spanwise position of the suction tubes and volumetric suction flow rate on the twin-tail buffet response are also investigated. The TLEB moves the path of leading-edge vortices laterally towards the twin tail, which increases the aero- dynamic damping on the tails. The FSVC effectively delays the breakdown location at high angles of attack. The computational model consists of a sharp-edged delta wing of aspect ratio one and swept-back flexible twin tail with taper ratio of 0.23. This complex multidisciplinary problem is solved sequentially using three sets of equations for the fluid flow, aeroelastic response and grid deformation, on a dynamic multi-block grid structure. The computational model is pitched at 30 deg. angle of attack. The freestream Mach number and Reynolds number are 0.3 and 1.25 million, respectively. The model is investigated for the inboard position of the twin tails, which corresponds to a separation distance between the twin tails of 33% of the wing span.

Can tail damage outbreaks in the pig be predicted by behavioural change?

PubMed

Larsen, Mona Lilian Vestbjerg; Andersen, Heidi Mai-Lis; Pedersen, Lene Juul

2016-03-01

Tail biting, resulting in outbreaks of tail damage in pigs, is a multifactorial welfare and economic problem which is usually partly prevented through tail docking. According to European Union legislation, tail docking is not allowed on a routine basis; thus there is a need for alternative preventive methods. One strategy is the surveillance of the pigs' behaviour for known preceding indicators of tail damage, which makes it possible to predict a tail damage outbreak and prevent it in proper time. This review discusses the existing literature on behavioural changes observed prior to a tail damage outbreak. Behaviours found to change prior to an outbreak include increased activity level, increased performance of enrichment object manipulation, and a changed proportion of tail posture with more tails between the legs. Monitoring these types of behaviours is also discussed for the purpose of developing an automatic warning system for tail damage outbreaks, with activity level showing promising results for being monitored automatically. Encouraging results have been found so far for the development of an automatic warning system; however, there is a need for further investigation and development, starting with the description of the temporal development of the predictive behaviour in relation to tail damage outbreaks. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microgravity-induced modifications of the vestibuloocular reflex in Xenopus laevis tadpoles are related to development and the occurrence of tail lordosis.

PubMed

Horn, Eberhard R

2006-08-01

During space flights, tadpoles of the clawed toad Xenopus laevis occasionally develop upward bended tails (tail lordosis). The tail lordosis disappears after re-entry to 1g within a couple of days. The mechanisms responsible for the induction of the tail lordosis are unknown; physical conditions such as weight de-loading or physiological factors such as decreased vestibular activity in microgravity might contribute. Microgravity (microg) also exerts significant effects on the roll-induced vestibuloocular reflex (rVOR). The rVOR was used to clarify whether tail lordosis is caused by physiological factors, by correlating the occurrence of microg-induced tail lordosis with the extent of microg-induced rVOR modifications. Post-flight recordings from three space flights (D-2 Spacelab mission, STS-55 in 1993; Shuttle-to-Mir mission SMM-06, STS-84 in 1997; French Soyuz taxi flight Andromède to ISS in 2001) were analyzed in these experiments. At onset of microgravity, tadpoles were at stages 25-28, 33-36 or 45. Parameters tested were rVOR gain (ratio between the angular eye movement and the lateral 30 degrees roll) and rVOR amplitude (maximal angular postural change of the eyes during a 360 degrees lateral roll). A ratio of 22-84% of tadpoles developed lordotic tails, depending on the space flight. The overall observation was that the rVOR of tadpoles with normal tails was either not affected by microgravity, or it was enhanced. In contrast, the rVOR of lordotic animals always revealed a depression. In particular, during post-flight days 1-11, tadpoles with lordotic tails from all three groups (25-28, 33-36 and 45) showed a lower rVOR gain and amplitude than the 1g-controls. The rVOR gain and amplitude of tadpoles from the groups 25-28 and 33-36 that developed normal tails was not affected by microgravity while the rVOR of microg-tadpoles from the stage-45 group with normal tails revealed a significant rVOR augmentation. (1) the vestibular system of tadpoles with lordotic

atonal regulates neurite arborization but does not act as a proneural gene in the Drosophila brain

NASA Technical Reports Server (NTRS)

Hassan, B. A.; Bermingham, N. A.; He, Y.; Sun, Y.; Jan, Y. N.; Zoghbi, H. Y.; Bellen, H. J.

2000-01-01

Drosophila atonal (ato) is the proneural gene of the chordotonal organs (CHOs) in the peripheral nervous system (PNS) and the larval and adult photoreceptor organs. Here, we show that ato is expressed at multiple stages during the development of a lineage of central brain neurons that innervate the optic lobes and are required for eclosion. A novel fate mapping approach shows that ato is expressed in the embryonic precursors of these neurons and that its expression is reactivated in third instar larvae (L3). In contrast to its function in the PNS, ato does not act as a proneural gene in the embryonic brain. Instead, ato performs a novel function, regulating arborization during larval and pupal development by interacting with Notch.

Curved tails in polymerization-based bacterial motility

NASA Astrophysics Data System (ADS)

Rutenberg, Andrew D.; Grant, Martin

2001-08-01

The curved actin ``comet-tail'' of the bacterium Listeria monocytogenes is a visually striking signature of actin polymerization-based motility. Similar actin tails are associated with Shigella flexneri, spotted-fever Rickettsiae, the Vaccinia virus, and vesicles and microspheres in related in vitro systems. We show that the torque required to produce the curvature in the tail can arise from randomly placed actin filaments pushing the bacterium or particle. We find that the curvature magnitude determines the number of actively pushing filaments, independent of viscosity and of the molecular details of force generation. The variation of the curvature with time can be used to infer the dynamics of actin filaments at the bacterial surface.

Mine tailings composition in a historic site: implications for ecological restoration.

PubMed

Courtney, R

2013-02-01

Ecological restoration, using tolerant plant species and nutrient additions, is a low-cost option to decrease environmental risks associated with mine tailings. An attempt was previously made to establish such a vegetation cover on an abandoned tailings facility in Southern Ireland. Historically, the tailings site has been prone to dusting and is a potential source of contamination to the surrounding environment. The site was examined to determine the success of the previous restoration plan used to revegetate the site and to determine its suitability for further restoration. Three distinct floristic areas were identified (grassland, poor grassland and bare area) based on herbage compositions and elemental analysis. Surface and subsurface samples were taken to characterise tailings from within these areas of the tailings site. The pH of bare surface tailings (pH, 2.7) was significantly more acidic (p < 0.5) than in other areas. Additionally, negligible net neutralising potential resulted in the tailings being hostile to plant growth. Total metal concentrations in tailings were high (c. 10,000 mg kg(-1) for Pb and up to 20,000 mg kg(-1) for Zn). DTPA-extractable Zn and Pb were 16 and 11 % of the total amount, respectively. Metal content in grasses growing on some areas of the tailings were elevated and demonstrated the inability of the tailings to support sustainable plant growth. Due to the inherently hostile characteristics of these areas, future restoration work will employ capping with a barrier layer.

AGES OF STAR CLUSTERS IN THE TIDAL TAILS OF MERGING GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mulia, A. J.; Chandar, R.; Whitmore, B. C.

We study the stellar content in the tidal tails of three nearby merging galaxies, NGC 520, NGC 2623, and NGC 3256, using BVI imaging taken with the Advanced Camera for Surveys on board the Hubble Space Telescope. The tidal tails in all three systems contain compact and fairly massive young star clusters, embedded in a sea of diffuse, unresolved stellar light. We compare the measured colors and luminosities with predictions from population synthesis models to estimate cluster ages and find that clusters began forming in tidal tails during or shortly after the formation of the tails themselves. We find amore » lack of very young clusters (≤10 Myr old), implying that eventually star formation shuts off in the tails as the gas is used up or dispersed. There are a few clusters in each tail with estimated ages that are older than the modeled tails themselves, suggesting that these may have been stripped out from the original galaxy disks. The luminosity function of the tail clusters can be described by a single power-law, dN/dL ∝ L{sup α}, with −2.6 < α < −2.0. We find a stellar age gradient across some of the tidal tails, which we interpret as a superposition of (1) newly formed stars and clusters along the dense center of the tail and (2) a sea of broadly distributed, older stellar material ejected from the progenitor galaxies.« less

Effects of plant growth-promoting bacteria isolated from copper tailings on plants in sterilized and non-sterilized tailings.

PubMed

Liu, Weiqiu; Yang, Chao; Shi, Si; Shu, Wensheng

2014-02-01

Ten strains of Cu-tolerant bacteria with potential plant growth-promoting ability were isolated by selecting strains with the ability to use 1-aminocyclopropane-1-carboxylate as a sole nitrogen source (designated ACC-B) or fix nitrogen (designated FLN-B) originating from the rhizosphere of plants growing on copper tailings. All 10 strains proved to have intrinsic ability to produce indole acetic acid and siderophores, and most of them could mobilize insoluble phosphate. In addition, a greenhouse study showed that ACC-B, FLN-B and a mixture of both had similar, potent ability to stimulate growth of Pennisetum purpureum, Medicago sativa and Oenothera erythrosepala plants grown on sterilized tailings. For instance, above-ground biomass of P. purpureum was 278-357% greater after 60d growth on sterilized tailings in their presence. They could also significantly promote the growth of the plants grown on non-sterilized tailings, though the growth-promoting effects were much weaker. So, strategies for using of the plant growth-promoting bacteria in the practice of phytoremediation deserve further studies to get higher growth-promoting efficiency. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Assessment of anti-tremorogenic drugs--nicotine-induced tail-tremor model].

PubMed

Suemaru, K; Kawasaki, H; Gomita, Y

1997-06-01

The repeated administration of nicotine at small doses, which do not produce whole body tremor or convulsion, causes tremor only in the tail (tail-tremor) of rats. The tremor is accompanied by locomotor hyperactivity without rigidity and immobility of the whole body, suggesting that the nicotine-induced tail-tremor model is useful for studying the mechanism underlying tremor associated with movement. The tail-tremor induced by nicotine was suppressed by mecamylamine, a nicotinic antagonist, but not by atropine or scopolamine, muscalinic antagonists. Moreover, the tail-tremor was suppressed by the beta-blockers propranolol and pindolol, as well as the benzodiazepines diazepam and clonazepam. Tremor at rest is observed only in Parkinson's disease, which is improved with anti-muscalinic drugs. Essential tremor is one of the typical tremors connected with movement (postural and kinetic tremor) and is improved with beta-blocker. These findings and results suggest that nicotine-induced tail-tremor is useful for the study of essential tremor in animal models.

Modeling of Longitudinal Unsteady Aerodynamics of a Wing-Tail Combination

NASA Technical Reports Server (NTRS)

Klein, Vladislav

1999-01-01

Aerodynamic equations for the longitudinal motion of an aircraft with a horizontal tail were developed. In this development emphasis was given on obtaining model structure suitable for model identification from experimental data. The resulting aerodynamic models included unsteady effects in the form of linear indicial functions. These functions represented responses in the lift on the wing and tail alone, and interference between those two lifting surfaces. The effect of the wing on the tail was formulated for two different expressions concerning the downwash angle at the tail. The first expression used the Cowley-Glauert approximation known-as "lag-in-downwash," the second took into account growth of the wing circulation and delay in the development of the lift on the tail. Both approaches were demonstrated in two examples using the geometry of a fighter aircraft and a large transport. It was shown that the differences in the two downwash formulations would increase for an aircraft with long tail arm performing low-speed, rapid maneuvers.

Managing 'tail liability'.

PubMed

Frese, Richard C; Weber, Ryan J

2013-11-01

To reduce and control their level of tail liability, hospitals should: Utilize a self-insurance vehicle; Consider combined limits between the hospital and physicians; Communicate any program changes to the actuary, underwriter, and auditor; Continue risk management and safety practices; Ensure credit is given to the organization's own medical malpractice program.

Identification of chromosomal locations associated with tail biting and being a victim of tail-biting behaviour in the domestic pig (Sus scrofa domesticus).

PubMed

Wilson, Kaitlin; Zanella, Ricardo; Ventura, Carlos; Johansen, Hanne Lind; Framstad, Tore; Janczak, Andrew; Zanella, Adroaldo J; Neibergs, Holly Louise

2012-11-01

The objective of this study was to identify loci associated with tail biting or being a victim of tail biting in Norwegian crossbred pigs using a genome-wide association study with PLINK case-control analysis. DNA was extracted from hair or blood samples collected from 98 trios of crossbred pigs located across Norway. Each trio came from the same pen and consisted of one pig observed to initiate tail biting, one pig which was the victim of tail biting and a control pig which was not involved in either behaviour. DNA was genotyped using the Illumina PorcineSNP60 BeadChip whole-genome single-nucleotide polymorphism (SNP) assay. After quality assurance filtering, 53,952 SNPs remained comprising 74 animals (37 pairs) for the tail biter versus control comparison and 53,419 SNPs remained comprising 80 animals (40 pairs) for the victim of tail biting versus control comparison. An association with being a tail biter was observed on Sus scrofa chromosome 16 (SSC16; p = 1.6 × 10(-5)) and an unassigned chromosome (p = 3.9 × 10(-5)). An association with being the victim of tail biting was observed on Sus scrofa chromosomes 1 (SSC1; p = 4.7 × 10(-5)), 9 (SSC9; p = 3.9 × 10(-5)), 18 (SSC18; p = 7 × 10(-5) for 9,602,511 bp, p = 3.4 × 10(-5) for 9,653,881 bp and p = 5.3 × 10(-5) for 29,577,783 bp) and an unassigned chromosome (p = 6.1 × 10(-5)). An r(2) = 0.96 and a D' = 1 between the two SNPs at 9 Mb on SSC18 indicated extremely high linkage disequilibrium, suggesting that these two markers represent a single locus. These results provide evidence of a moderate genetic association between the propensity to participate in tail-biting behaviour and the likelihood of becoming a victim of this behaviour.

A review on in situ phytoremediation of mine tailings.

PubMed

Wang, Li; Ji, Bin; Hu, Yuehua; Liu, Runqing; Sun, Wei

2017-10-01

Mine tailings are detrimental to natural plant growth due to their physicochemical characteristics, such as high pH, high salinity, low water retention capacity, high heavy metal concentrations, and deficiencies in soil organic matter and fertility. Thus, the remediation of mine tailings has become a key issue in environmental science and engineering. Phytoremediation, an in situ cost-effective technology, is emerging as the most promising remediation method for mine tailings by introducing tolerant plant species. It is particularly effective in dealing with large-area mine tailings with shallow contamination of organic, nutrient and metal pollutants. In this review, the background, concepts and applications of phytoremediation are comprehensively discussed. Furthermore, proper amendments used to improve the physical, chemical and biological properties of mine tailings are systematically reviewed and compared. Emphasis is placed on the types and characteristics of tolerant plants and their role in phytoremediation. Moreover, the role of microorganisms and their mechanism in phytoremediation are also discussed in-depth. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rapid oxidation of sulfide mine tailings by reaction with potassium ferrate.

PubMed

Murshed, Mohamed; Rockstraw, David A; Hanson, Adrian T; Johnson, Michael

2003-01-01

The chemistry of sulfide mine tailings treated with potassium ferrate (K2FeO4) in aqueous slurry has been investigated. The reaction system is believed to parallel a geochemical oxidation in which ferrate ion replaces oxygen. This chemical system utilized in a pipeline (as a plug flow reactor) may have application eliminating the potential for tailings to leach acid while recovering the metal from the tailings. Elemental analyses were performed using an ICP spectrometer for the aqueous phase extract of the treated tailings; and an SEM-EDX for the tailing solids. Solids were analyzed before and after treatments were applied. ICP shows that as the mass ratio of ferrate ion to tailings increases, the concentration of metals in the extract solution increases; while EDX indicates a corresponding decrease in sulfur content of the tailing solids. The extraction of metal and reduction in sulfide content is significant. The kinetic timeframe is on the order of minutes.

Ultra-low dose naltrexone enhances cannabinoid-induced antinociception.

PubMed

Paquette, Jay; Olmstead, Mary C; Olmstead, Mary

2005-12-01

Both opioids and cannabinoids have inhibitory effects at micromolar doses, which are mediated by activated receptors coupling to Gi/o-proteins. Surprisingly, the analgesic effects of opioids are enhanced by ultra-low doses (nanomolar to picomolar) of the opioid antagonist, naltrexone. As opioid and cannabinoid systems interact, this study investigated whether ultra-low dose naltrexone also influences cannabinoid-induced antinociception. Separate groups of Long-Evans rats were tested for antinociception following an injection of vehicle, a sub-maximal dose of the cannabinoid agonist WIN 55 212-2, naltrexone (an ultra-low or a high dose) or a combination of WIN 55 212-2 and naltrexone doses. Tail-flick latencies were recorded for 3 h, at 10-min intervals for the first hour, and at 15-min intervals thereafter. Ultra-low dose naltrexone elevated WIN 55 212-2-induced tail flick thresholds without extending its duration of action. This enhancement was replicated in animals receiving intraperitoneal or intravenous injections. A high dose of naltrexone had no effect on WIN 55 212-2-induced tail flick latencies, but a high dose of the cannabinoid 1 receptor antagonist SR 141716 blocked the elevated tail-flick thresholds produced by WIN 55 212-2+ultra-low dose naltrexone. These data suggest a mechanism of cannabinoid-opioid interaction whereby activated opioid receptors that couple to Gs-proteins may attenuate cannabinoid-induced antinociception and/or motor functioning.

Tailings dam-break flow - Analysis of sediment transport

NASA Astrophysics Data System (ADS)

Aleixo, Rui; Altinakar, Mustafa

2015-04-01

A common solution to store mining debris is to build tailings dams near the mining site. These dams are usually built with local materials such as mining debris and are more vulnerable than concrete dams (Rico et al. 2008). of The tailings and the pond water generally contain heavy metals and various toxic chemicals used in ore extraction. Thus, the release of tailings due to a dam-break can have severe ecological consequences in the environment. A tailings dam-break has many similarities with a common dam-break flow. It is highly transient and can be severely descructive. However, a significant difference is that the released sediment-water mixture will behave as a non-Newtonian flow. Existing numerical models used to simulate dam-break flows do not represent correctly the non-Newtonian behavior of tailings under a dam-break flow and may lead to unrealistic and incorrect results. The need for experiments to extract both qualitative and quantitative information regarding these flows is therefore real and actual. The present paper explores an existing experimental data base presented in Aleixo et al. (2014a,b) to further characterize the sediment transport under conditions of a severe transient flow and to extract quantitative information regarding sediment flow rate, sediment velocity, sediment-sediment interactions a among others. Different features of the flow are also described and analyzed in detail. The analysis is made by means of imaging techniques such as Particle Image Velocimetry and Particle Tracking Velocimetry that allow extracting not only the velocity field but the Lagrangian description of the sediments as well. An analysis of the results is presented and the limitations of the presented experimental approach are discussed. References Rico, M., Benito, G., Salgueiro, AR, Diez-Herrero, A. and Pereira, H.G. (2008) Reported tailings dam failures: A review of the European incidents in the worldwide context , Journal of Hazardous Materials, 152, 846

A tail like no other. The RPC-MAG view of Rosetta's tail excursion at comet 67P/Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Volwerk, Martin; Goetz, Charlotte; Richter, Ingo; Delva, Magda; Ostaszewski, Katharina; Schwingenschuh, Konrad; Glassmeier, Karl-Heinz

2018-06-01

Context. The Rosetta Plasma Consortium (RPC) magnetometer (MAG) data during the tail excursion in March-April 2016 are used to investigate the magnetic structure of and activity in the tail region of the weakly outgassing comet 67P/Churyumov-Gerasimenko (67P). Aims: The goal of this study is to compare the large scale (near) tail structure with that of earlier missions to strong outgassing comets, and the small scale turbulent energy cascade (un)related to the singing comet phenomenon. Methods: The usual methods of space plasma physics are used to analyse the magnetometer data, such as minimum variance analysis, spectral analysis, and power law fitting. Also the cone angle and clock angle of the magnetic field are calculated to interpret the data. Results: It is found that comet 67P does not have a classical draped magnetic field and no bi-lobal tail structure at this late stage of the mission when the comet is already at 2.7 AU distance from the Sun. The main magnetic field direction seems to be more across the tail direction, which may implicate an asymmetric pick-up cloud. During periods of singing comet activity the propagation direction of the waves is at large angles with respect to the magnetic field and to the radial direction towards the comet. Turbulent cascade of magnetic energy from large to small scales is different in the presence of singing as without it.

Remote control canard missile with a free-rolling tail brake torque system

NASA Technical Reports Server (NTRS)

Blair, A. B., Jr.

1981-01-01

An experimental wind-tunnel investigation has been conducted at supersonic Mach numbers to determine the static aerodynamic characteristics of a cruciform canard-controlled missile with fixed and free-rolling tail-fin afterbodies. Mechanical coupling effects of the free-rolling tail afterbody were investigated using an electronic/electromagnetic brake system that provides arbitrary tail-fin brake torques with continuous measurements of tail-to-mainframe torque and tail-roll rate. Results are summarized to show the effects of fixed and free-rolling tail-fin afterbodies that include simulated measured bearing friction torques on the longitudinal and lateral-directional aerodynamic characteristics.

Amazonian phylogeography: mtDNA sequence variation in arboreal echimyid rodents (Caviomorpha).

PubMed

da Silva, M N; Patton, J L

1993-09-01

Patterns of evolutionary relationships among haplotype clades of sequences of the mitochondrial cytochrome b DNA gene are examined for five genera of arboreal rodents of the Caviomorph family Echimyidae from the Amazon Basin. Data are available for 798 bp of sequence from a total of 24 separate localities in Peru, Venezuela, Bolivia, and Brazil for Mesomys, Isothrix, Makalata, Dactylomys, and Echimys. Sequence divergence, corrected for multiple hits, is extensive, ranging from less than 1% for comparisons within populations of over 20% among geographic units within genera. Both the degree of differentiation and the geographic patterning of the variation suggest that more than one species composes the Amazonian distribution of the currently recognized Mesomys hispidus, Isothrix bistriata, Makalata didelphoides, and Dactylomys dactylinus. There is general concordance in the geographic range of haplotype clades for each of these taxa, and the overall level of differentiation within them is largely equivalent. These observations suggest that a common vicariant history underlies the respective diversification of each genus. However, estimated times of divergence based on the rate of third position transversion substitutions for the major clades within each genus typically range above 1 million years. Thus, allopatric isolation precipitating divergence must have been considerably earlier than the late Pleistocene forest fragmentation events commonly invoked for Amazonian biota.

White-tailed deer

Treesearch

Paul E. Johns; John C. Kilgo

2005-01-01

from a public relations standpoint, the white-tailed deer (Odocileus virginiamus) is probably the most important wildlife species occurring on the Savannah River Site (SRS). The SRS deer herd has been the subject of more scientific investigations than any comparable deer population in the world, resulting in more than 125 published papers. Each year...

Research investigation of helicopter main rotor/tail rotor interaction noise

NASA Technical Reports Server (NTRS)

Fitzgerald, J.; Kohlhepp, F.

1988-01-01

Acoustic measurements were obtained in a Langley 14 x 22 foot Subsonic Wind Tunnel to study the aeroacoustic interaction of 1/5th scale main rotor, tail rotor, and fuselage models. An extensive aeroacoustic data base was acquired for main rotor, tail rotor, fuselage aerodynamic interaction for moderate forward speed flight conditions. The details of the rotor models, experimental design and procedure, aerodynamic and acoustic data acquisition and reduction are presented. The model was initially operated in trim for selected fuselage angle of attack, main rotor tip-path-plane angle, and main rotor thrust combinations. The effects of repositioning the tail rotor in the main rotor wake and the corresponding tail rotor countertorque requirements were determined. Each rotor was subsequently tested in isolation at the thrust and angle of attack combinations for trim. The acoustic data indicated that the noise was primarily dominated by the main rotor, especially for moderate speed main rotor blade-vortex interaction conditions. The tail rotor noise increased when the main rotor was removed indicating that tail rotor inflow was improved with the main rotor present.

Giant Metrewave Radio Telescope Observations of Head–Tail Radio Galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sebastian, Biny; Lal, Dharam V.; Rao, A. Pramesh, E-mail: biny@ncra.tifr.res.in

We present results from a study of seven large known head–tail radio galaxies based on observations using the Giant Metrewave Radio Telescope at 240 and 610 MHz. These observations are used to study the radio morphologies and distribution of the spectral indices across the sources. The overall morphology of the radio tails of these sources is suggestive of random motions of the optical host around the cluster potential. The presence of multiple bends and wiggles in several head–tail sources is possibly due to the precessing radio jets. We find steepening of the spectral index along the radio tails. The prevailingmore » equipartition magnetic field also decreases along the radio tails of these sources. These steepening trends are attributed to the synchrotron aging of plasma toward the ends of the tails. The dynamical ages of these sample sources have been estimated to be ∼10{sup 8} yr, which is a factor of six more than the age estimates from the radiative losses due to synchrotron cooling.« less

Plasma currents and anisotropy in the tail-dipole transition region

NASA Astrophysics Data System (ADS)

Artemyev, A.; Zhang, X. J.; Angelopoulos, V.; Runov, A.

2017-12-01

Using conjugated THEMIS and Van Allen Probes observations in the nightside magnetosphere, we examine statistically plasma and magnetic field characteristics at multiple locations simultaneously across the 3-10 RE region (i.e., across the tail-dipole transition region, whose location depends on tail flux loading and the strength of global convection). We find that the spatial distributions of ion and electron anisotropies vary significantly but systematically with radial distance and geomagnetic activity. For low Kp (<2), ions are transversely anisotropic near Earth but isotropic in the tail, whereas electrons are isotropic closer to Earth but field-aligned in tail. For large Kp (>4), the anisotropy profiles for ions and electrons reverse: ions are isotropic closer to the Earth and field-aligned in the tail, whereas electrons are transversely anisotropic closer to Earth but isotropic in the tail. Using the measured plasma anisotropy radial profiles we estimate the currents from curvature drifts and compare them with diamagnetic currents. We also discuss the implications of the observed plasma anisotropies for the presence and spatial distribution of field-aligned electric fields.

Use of cemented paste backfill in arsenic-rich tailings

NASA Astrophysics Data System (ADS)

Hamberg, Roger; Maurice, Christian; Alakangas, Lena

2015-04-01

Gold is extracted by cyanide leaching from inclusions in arsenopyrite from a mine in the north of Sweden. The major ore mineral assemblage consists of pyrrhotite and arsenopyrite-loellingite. Effluents from the gold extraction were treated with Fe2(SO4)3, with the aim to form stable As-bearing Fe-precipitates (FEP). The use of the method called cemented paste backfill (CPB) is sometimes suggested for the management of tailings. In CPB, tailings are commonly mixed with low proportions (3 - 7 %) of cement and backfilled into underground excavated area. To reduce costs, amendments such as granulated blast furnace slag (GBFS), biofuel fly ash (BFA) and cement kiln dust (CKD) are used for partial replacement of cement in CPB due to their pozzolanic and alkaline properties. The objective for this study was to evaluate the leaching behaviour of As in CPB-mixtures with low proportions (1 - 3 %) of BFA and ordinary cement and unmodified tailings. The selection of CPB-recipies was made based on technical and economical criterias to adress the demands deriving from the mining operations. Speciation of the As in ore and tailings samples revealed that mining processes have dissolved the majority of the arsenopyrite in the ore, causing secondary As phases to co-precipitate with newly formed FEP:s. Tank leaching tests (TLT) and weathering cells (WCT) were used to compare leaching behaviour in a monolithic mass contra a crushed material. Quantification of the presumed benefit of CPB was made by calculation of the cumulative leaching of As. Results from the leaching tests (TLT and WCT) showed that the inclusion of As-rich tailings into a cementitious matrix increased leaching of As. This behaviour could partially be explained by an increase of pH. The addition of alkaline binder materials to tailings increased As leaching due to the relocation of desorbed As from FEPs into less acid-tolerant species such as Ca-arsenates and cementitious As-phases. Unmodified tailings generated an

14 CFR 29.481 - Tail-down landing conditions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tail-down landing conditions. 29.481 Section 29.481 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Tail-down landing conditions. (a) The rotorcraft is assumed to be in the maximum nose-up attitude...

14 CFR 27.481 - Tail-down landing conditions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tail-down landing conditions. 27.481 Section 27.481 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Tail-down landing conditions. (a) The rotorcraft is assumed to be in the maximum nose-up attitude...

Impact of ozonation on particle aggregation in mature fine tailings.

PubMed

Liang, Jiaming; Tumpa, Fahmida; Pérez Estrada, Leonidas; Gamal El-Din, Mohamed; Liu, Yang

2014-12-15

The extraction of bitumen from the oil sands in Canada generates tonnes of mature fine tailings (MFT), consisting of a mineral matrix of sand, clay, and water, which without treatment requires thousands of years to fully consolidate. We assessed the performance of a novel ozonation method designed to enhance the settling of MFT and explored the mechanisms involved. The solid content of MFT obtained from oil sands tailings was adjusted to 1, 3, 5 wt % with water before applying 15, 30, and 60 min of ozonation. MFT settled after a short (15 min) ozonation treatment, resulting in a sample with clear released water on the top and condensed sludge at the bottom. The water chemistry characteristics, particles' surface charge and chemical bonding were measured. Ozonation led to the increased organic acids concentrations in MFT suspension through converting of organic matter from high to low molecular weight, and detaching organic coating on MFT particles. The pH and the concentrations of ions in the MFT suspension were changed significantly, an association of metal ions with MFT particles was promoted, and the surface charges of MFT particles were neutralized. Consequently, the MFT suspension was destabilized and MFT particle precipitation was observed. Copyright © 2014 Elsevier Ltd. All rights reserved.

From Globular Clusters to Tidal Dwarfs: Structure Formation in Tidal Tails

NASA Astrophysics Data System (ADS)

Knierman, K.; Hunsberger, S.; Gallagher, S.; Charlton, J.; Whitmore, B.; Hibbard, J.; Kundu, A.; Zaritsky, D.

1999-12-01

Galaxy interactions trigger star formation in tidal debris. How does this star formation depend on the local and global physical conditions? Using WFPC2/HST images, we investigate the range of structure within tidal tails of four classic ``Toomre Sequence'' mergers: NGC 4038/9 (``Antennae''), NGC 7252 (``Atoms for Peace''), NGC 3921, and NGC 3256. These tails contain a variety of stellar associations with sizes from globular clusters up to dwarf Irregulars. We explore whether there is a continuum between the two extremes. Our eight fields sample seven tidal tails at a variety of stages in the evolutionary sequence. Some of these tails are rich in HI while others are HI poor. Large tidal dwarfs are embedded in three of the tails. Using V and I WFPC2 images, we measure luminosities and colors of substructures within the tidal tails. The properties of globular cluster candidates in the tails will be contrasted with those of the hundreds of young clusters in the central regions of these mergers. We address whether globular clusters form and survive in the tidal tails and whether tidal dwarfs are composed of only young stars. By comparing the properties of structures in the tails of the four mergers with different ages, we examine systematic evolution of structure along the evolutionary sequence and as a function of HI content. We acknowledge support from NASA through STScI, and from NSF for an REU supplement for Karen Knierman.

Evidence for the consumption of arboreal, diurnal primates by bonobos (Pan paniscus).

PubMed

Surbeck, Martin; Fowler, Andrew; Deimel, Caroline; Hohmann, Gottfried

2009-02-01

We present evidence for the consumption of a diurnal, arboreal, group living primate by bonobos. The digit of an immature black mangabey (Lophocebus aterrimus) was found in the fresh feces of a bonobo (Pan paniscus) at the Lui Kotale study site, Democratic Republic of Congo. In close proximity to the fecal sample containing the remains of the digit, we also found a large part of the pelt of a black mangabey. Evidence suggests that the Lui Kotale bonobos consume more meat than other bonobo populations and have greater variation in the mammalian species exploited than previously thought [Hohmann & Fruth, Folia primatologica 79:103-110]. The current finding supports Stanford's argument [Current Anthropology 39:399-420] that some differences in the diet and behavior between chimpanzees (P. troglodytes) and bonobos are an artefact of the limited number of bonobo study populations. If bonobos did obtain the monkey by active hunting, this would challenge current evolutionary models relating the intra-specific aggression and violence seen in chimpanzees and humans to hunting and meat consumption [Wrangham, Yearbook of Physical Anthropology 42:1-30]. (c) 2008 Wiley-Liss, Inc.

An arboreal spider protects its offspring by diving into the water of tank bromeliads.

PubMed

Hénaut, Yann; Corbara, Bruno; Azémar, Frédéric; Céréghino, Régis; Dézerald, Olivier; Dejean, Alain

2018-03-01

Cupiennius salei (Ctenidae) individuals frequently live in association with tank bromeliads, including Aechmea bracteata, in Quintana Roo (Mexico). Whereas C. salei females without egg sacs hunt over their entire host plant, females carrying egg sacs settle above the A. bracteata reservoirs they have partially sealed with silk. There they avoid predators that use sight to detect their prey, as is known for many bird species. Furthermore, if a danger is more acute, these females dive with their egg sacs into the bromeliad reservoir. An experiment showed that this is not the case for males or females without egg sacs. In addition to the likely abundance of prey found therein, the potential of diving into the tank to protect offspring may explain the close association of this spider with bromeliads. These results show that, although arboreal, C. salei evolved a protective behavior using the water of tank bromeliads to protect offspring. Copyright © 2018 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.

[Effects of socializing piglets in lactation on behaviour, including tail-biting, in growing and finishing pigs].

PubMed

Klein, Sandrina; Patzkéwitsch, Dorian; Reese, Sven; Erhard, Michael

2016-06-16

The aim of this study was to determine whether early socialising of piglets influences the later behaviour and the risk of tail biting in growing and finishing pigs. The behaviour of 183 animals (divided in three successive runs) was recorded from birth until the end of the fattening period. Furthermore, the condition of the teats of the sows as well as the integument and tails of the growing and finishing pigs were evaluated. To socialize the piglets, four litters of the experimental group (V) were provided with additional space (walkway) by opening "piglet-doors" (day 10 postpartum of the youngest litter). The piglets of the control group (K) were reared in conventional farrowing crates located in the same compartment of the stable. Post-weaning, the piglets were assigned to three groups: the experimental group (V/V, two litters of group V), the control group (K/K, two litters of group K) and the mixed group (V/K, one litter of group V and one litter of group K). After opening the "piglet-doors", piglets of group V displayed significantly more playing behaviour than piglets of group K. Additionally, the agonistic behaviour increased in group V. Post-weaning, at allocation and mixing, animals of group V/V showed significantly less agonistic behaviour than pigs of group K/K. Tail-biting behaviour occurred in all three groups, but only in runs two and three. On the 100th day of the fattening period, 58.7% of the pigs of group V/V, 51.7% of group V/K and 43.3% of group K/K still had intact tails. In pigs of group K/K, the tails were significantly shorter compared to the other two groups. Early socialization enhances piglet welfare in farrowing pens by encouraging playing behaviour. Less agonistic behaviour at allocation could furthermore reduce stress at mixing and allocation. The aim to reduce the incidence of tail-biting could not be achieved. However, socializing piglets in lactation could contribute, in accordance with other measures, to an influence on biting

Geo-Semantic Framework for Integrating Long-Tail Data and Model Resources for Advancing Earth System Science

NASA Astrophysics Data System (ADS)

Elag, M.; Kumar, P.

2014-12-01

and preservation of long-tail data during its life-cycle; (ii) BrownDog, which enhances the machine interpretability of large unstructured and uncurated data; and (iii) CSDMS (Community Surface Dynamics Modeling System), which "componentizes" models by providing plug-and-play environment for models integration.

Postautotomy tail activity in the Balearic lizard, Podarcis lilfordi

NASA Astrophysics Data System (ADS)

Pafilis, Panayiotis; Pérez-Mellado, Valentín; Valakos, Efstratios

2008-03-01

Caudal autotomy is an effective antipredator strategy widespread among lizards. The shed tail thrashes vigorously for long periods to distract the predator and facilitate the lizard’s escape. This movement is maintained by energy supplied by the anaerobic conversion of glycogen into lactate. It has been suggested that lactate accumulation serves as an index for the vigor of tail thrashing. We made three predictions: (1) tail loss frequency should be higher under heavier predation regime, (2) the duration of postautotomy tail movement should be extended in populations under heavy predation pressure as an adaptation to the higher risk and the increased need for defense, and (3) as result, lactate in these tail tissues should be concentrated at higher levels. To eliminate the impact of phylogeny and environmental factors on the interpretation of our result, we focused exclusively on one species, the Balearic lizard ( Podarcis lilfordi). We studied three populations under different predation pressure but sharing the same climatic conditions. We found no differences among the studied populations either in postautotomy duration of tail movement or in levels of final lactate accumulation while autotomy frequency was higher where predation pressure was more intense. Τail loss effectiveness is directly influenced by the level of predation, while secondary features of the trait appear to remain independent from the impact of environment.

Postsacral vertebral morphology in relation to tail length among primates and other mammals.

PubMed

Russo, Gabrielle A

2015-02-01

Tail reduction/loss independently evolved in a number of mammalian lineages, including hominoid primates. One prerequisite to appropriately contextualizing its occurrence and understanding its significance is the ability to track evolutionary changes in tail length throughout the fossil record. However, to date, the bony correlates of tail length variation among living taxa have not been comprehensively examined. This study quantifies postsacral vertebral morphology among living primates and other mammals known to differ in relative tail length (RTL). Linear and angular measurements with known biomechanical significance were collected on the first, mid-, and transition proximal postsacral vertebrae, and their relationship with RTL was assessed using phylogenetic generalized least-squares regression methods. Compared to shorter-tailed primates, longer-tailed primates possess a greater number of postsacral vertebral features associated with increased proximal tail flexibility (e.g., craniocaudally longer vertebral bodies), increased intervertebral body joint range of motion (e.g., more circularly shaped cranial articular surfaces), and increased leverage of tail musculature (e.g., longer spinous processes). These observations are corroborated by the comparative mammalian sample, which shows that distantly related short-tailed (e.g., Phascolarctos, Lynx) and long-tailed (e.g., Dendrolagus, Acinonyx) nonprimate mammals morphologically converge with short-tailed (e.g., Macaca tonkeana) and long-tailed (e.g., Macaca fascicularis) primates, respectively. Multivariate models demonstrate that the variables examined account for 70% (all mammals) to 94% (only primates) of the variance in RTL. Results of this study may be used to infer the tail lengths of extinct primates and other mammals, thereby improving our understanding about the evolution of tail reduction/loss. © 2014 Wiley Periodicals, Inc.

Spectral induced polarization (SIP) response of mine tailings.

PubMed

Placencia-Gómez, Edmundo; Parviainen, Annika; Slater, Lee; Leveinen, Jussi

2015-02-01

Mine tailings impoundments are a source of leachates known as acid mine drainage (AMD) which can pose a contamination risk for surrounding surface and groundwater. Methodologies which can help management of this environmental issue are needed. We carried out a laboratory study of the spectral induced polarization (SIP) response of tailings from the Haveri Au-Cu mine, SW Finland. The primary objectives were, (1) to determine possible correlations between SIP parameters and textural properties associated with oxidative-weathering mechanisms, mineralogical composition and metallic content, and (2) to evaluate the effects of the pore water chemistry on SIP parameters associated with redox-inactive and redox-active electrolytes varying in molar concentration, conductivity and pH. The Haveri tailings exhibit well defined relaxation spectra between 100 and 10,000Hz. The relaxation magnitudes are governed by the in-situ oxidative-weathering conditions on sulphide mineral surfaces contained in the tailings, and decrease with the oxidation degree. The oxidation-driven textural variation in the tailings results in changes to the frequency peak of the phase angle, the imaginary conductivity and chargeability, when plotted versus the pore water conductivity. In contrast, the real and the formation electrical conductivity components show a single linear dependence on the pore water conductivity. The increase of the pore water conductivity (dominated by the increase of ions concentration in solution) along with a transition to acidic conditions shifts the polarization peak towards higher frequencies. These findings show the unique sensitivity of the SIP method to potentially discriminate AMD discharges from reactive oxidation zones in tailings, suggesting a significant advantage for monitoring threatened aquifers. Copyright © 2014 Elsevier B.V. All rights reserved.

Spectral induced polarization (SIP) response of mine tailings

NASA Astrophysics Data System (ADS)

Placencia-Gómez, Edmundo; Parviainen, Annika; Slater, Lee; Leveinen, Jussi

2015-02-01

Mine tailings impoundments are a source of leachates known as acid mine drainage (AMD) which can pose a contamination risk for surrounding surface and groundwater. Methodologies which can help management of this environmental issue are needed. We carried out a laboratory study of the spectral induced polarization (SIP) response of tailings from the Haveri Au-Cu mine, SW Finland. The primary objectives were, (1) to determine possible correlations between SIP parameters and textural properties associated with oxidative-weathering mechanisms, mineralogical composition and metallic content, and (2) to evaluate the effects of the pore water chemistry on SIP parameters associated with redox-inactive and redox-active electrolytes varying in molar concentration, conductivity and pH. The Haveri tailings exhibit well defined relaxation spectra between 100 and 10,000 Hz. The relaxation magnitudes are governed by the in-situ oxidative-weathering conditions on sulphide mineral surfaces contained in the tailings, and decrease with the oxidation degree. The oxidation-driven textural variation in the tailings results in changes to the frequency peak of the phase angle, the imaginary conductivity and chargeability, when plotted versus the pore water conductivity. In contrast, the real and the formation electrical conductivity components show a single linear dependence on the pore water conductivity. The increase of the pore water conductivity (dominated by the increase of ions concentration in solution) along with a transition to acidic conditions shifts the polarization peak towards higher frequencies. These findings show the unique sensitivity of the SIP method to potentially discriminate AMD discharges from reactive oxidation zones in tailings, suggesting a significant advantage for monitoring threatened aquifers.

Comparing Phlebotomy by Tail Tip Amputation, Facial Vein Puncture, and Tail Vein Incision in C57BL/6 Mice by Using Physiologic and Behavioral Metrics of Pain and Distress

PubMed Central

Moore, Elizabeth S; Cleland, Thomas A; Williams, Wendy O; Peterson, Christine M; Singh, Bhupinder; Southard, Teresa L; Pasch, Bret; Labitt, Rachael N; Daugherity, Erin K

2017-01-01

Tail tip amputation with minimal restraint is not widely used for mouse phlebotomy. In part, this infrequency may reflect policies influenced by tail tip amputation procedures for genotyping, which involve greater handling and tissue removal. To assess tail tip amputation with minimal restraint as a phlebotomy technique, we compared it with 2 more common methods: scruffing with facial vein puncture and lateral tail vein incision with minimal restraint. Blood glucose levels, audible and ultrasonic vocalizations, postphlebotomy activity and grooming behavior, open field and elevated plus maze behaviors, nest-building scores, and histologic changes at the phlebotomy site were evaluated. Mice in the facial vein phlebotomy group produced more audible vocalizations, exhibited lower postphlebotomy activity in the open field, and had more severe histologic changes than did mice in the tail incision and tail tip amputation groups. Facial vein phlebotomy did not affect grooming behavior relative to sham groups, whereas tail vein incision—but not tail tip amputation—increased tail grooming compared with that in control mice. Blood glucose levels, nest-building scores, and elevated plus maze behavior did not differ between groups, and no mice in any group produced ultrasonic vocalizations. Tail tip amputation mice did not perform differently than sham mice in any metric analyzed, indicating that this technique is a potentially superior method of blood collection in mice in terms of animal wellbeing. PMID:28535866

Comparing Phlebotomy by Tail Tip Amputation, Facial Vein Puncture, and Tail Vein Incision in C57BL/6 Mice by Using Physiologic and Behavioral Metrics of Pain and Distress.

PubMed

Moore, Elizabeth S; Cleland, Thomas A; Williams, Wendy O; Peterson, Christine M; Singh, Bhupinder; Southard, Teresa L; Pasch, Bret; Labitt, Rachael N; Daugherity, Erin K

2017-05-01

Tail tip amputation with minimal restraint is not widely used for mouse phlebotomy. In part, this infrequency may reflect policies influenced by tail tip amputation procedures for genotyping, which involve greater handling and tissue removal. To assess tail tip amputation with minimal restraint as a phlebotomy technique, we compared it with 2 more common methods: scruffing with facial vein puncture and lateral tail vein incision with minimal restraint. Blood glucose levels, audible and ultrasonic vocalizations, postphlebotomy activity and grooming behavior, open field and elevated plus maze behaviors, nest-building scores, and histologic changes at the phlebotomy site were evaluated. Mice in the facial vein phlebotomy group produced more audible vocalizations, exhibited lower postphlebotomy activity in the open field, and had more severe histologic changes than did mice in the tail incision and tail tip amputation groups. Facial vein phlebotomy did not affect grooming behavior relative to sham groups, whereas tail vein incision-but not tail tip amputation-increased tail grooming compared with that in control mice. Blood glucose levels, nest-building scores, and elevated plus maze behavior did not differ between groups, and no mice in any group produced ultrasonic vocalizations. Tail tip amputation mice did not perform differently than sham mice in any metric analyzed, indicating that this technique is a potentially superior method of blood collection in mice in terms of animal wellbeing.

Assessment of Phytostabilization Success in Metalliferous Acid Mine Tailings

NASA Astrophysics Data System (ADS)

Wang, Y.; Root, R. A.; Hammond, C.; Amistadi, M. K.; Maier, R. M.; Chorover, J.

2014-12-01

Legacy mine tailings are a significant source of metal(loid)s due to wind and water erosion, especially in the arid southwest, and exposure to fugative dusts presents a health risk to surrounding populations. Compost assisted phytostabilization has been implemented to reduce off site emissions at the Iron King Mine U.S. Superfund Site in central Arizona, concurrent with a greenhouse mesocosm study for detailed study of subsurface mechanisms. Quantification of plant available toxic metal(loid)s in the amended tailings was accessed with a targeted single extraction of diethylenetriaminepentaactic acid (DTPA). Greenhouse mesocosms (1m dia, 0.4 m deep), run in triplicate, mimicked field treatments with: i) tailings only control (TO), ii) tailings plus 15 wt% compost (TC), iii) TC + quailbush seeds (TCA), and iv) TC + buffalo grass seeds (TCB). Core samples collected at 3-month intervals for 1 year were dissected by depth (10 cm each) for analysis. DTPA results indicated that compost treated samples decreased plant availability of Al, As, Cd, Cu, Fe, and Pb but increased Mn and Zn compared with TO. TCB decreased plant available metal(loid)s at all depths, whereas TCA plant available Al, As, Cd, Cu, Fe, Mn and Zn increased in the deeper 20-30cm and 30-40 cm relative to TCB. Samples from the greenhouse were compared to tailings from both the field site and tailings impacted soils used to grow vegetables. Mineral transformations and metal complexation, in the pre- and post-extracted tailings were analyzed by synchrotron transmission XRD and FTIR spectroscopy. The temporal change in plant available metal(loid)s in response to phytostabilization indicates mineralogical alteration that improves soil quality by reducing plant available metal(loid)s. These results will aid in the understanding and efficacy of phytostabilization as a means of remediating and reducing toxicity on mine tailings as well as providing information on health risk management in the region.

Effects of submarine mine tailings on macrobenthic community structure and ecosystem processes.

PubMed

Trannum, Hilde C; Gundersen, Hege; Escudero-Oñate, Carlos; Johansen, Joachim T; Schaanning, Morten T

2018-07-15

A mesocosm experiment with intact benthic communities was conducted to evaluate the effects of mine tailings on benthic community structure and biogeochemical processes. Two types of tailings were supplied from process plants using flotation and flocculation chemicals, while a third type was absent of added chemicals. All tailings impacted the sediment community at thin layers, and through more mechanisms than merely hypersedimentation. In general, the strongest impact was observed in a very fine-grained tailings containing flotation chemicals. The second strongest occurred in tailings with no process chemicals. The tailings with flocculation chemicals initiated the weakest response. Fluxes of oxygen, nitrate and ammonium provided some indications on biodegradation of organic phases. Release of phosphate and silicate decreased with increasing layer thickness of all three tailings. A threshold level of 2cm was identified both for faunal responses and for fluxes of phosphate and silicate. The particular impact mechanisms should receive more attention in future studies in order to minimize the environmental risk associated with tailings disposal. Copyright © 2018 Elsevier B.V. All rights reserved.

Evaluation of metal mobility from copper mine tailings in northern Chile.

PubMed

Lam, Elizabeth J; Gálvez, M E; Cánovas, M; Montofré, I L; Rivero, D; Faz, A

2016-06-01

This work shows the results obtained on a copper mine tailing in the Antofagasta Region, Chile. The tailing was classified as saline-sodic with high concentrations of metals, especially Cu and Fe, with pH 8.4. Our objectives were to (1) compare the physicochemical properties of the tailing with surrounding soils of the mine under study, and (2) evaluate the effect of two amendments (CaCO3 and compost) and their mixtures on Cu(2+), Mn, Fe, Zn, Mg(2+), and K(+) and Ca(2+), SO4 (2-), NO3 (-), and PO4 (3-) leaching. The data obtained were submitted to variance and covariance analysis. The results from the comparison between both substrates showed that in general, the tailing presented greater content of metals. Regarding tailing leaching, pH, electrical conductivity (EC), and concentration of the elements of interest were measured. The statistical analysis showed that Cu(2+) leaching and immobilization of Fe occurred to the greatest extent with compost. The EC decreased throughout the experiment with irrigation and increased upon treatment with compost. The major interactions found among the chemical parameters were (1) tailings without treatment, Cu(2+)/Fe and NO3 (-)/SO4 (2-); (2) tailings treated with CaCO3, Cu(2+)/K(+); (3) tailings treated with compost, NO3 (-)/SO4 (-2) and EC/Cu(2+); and (4) tailings treated with both amendments, EC/Fe and Cu(2+)/Fe. The ANOVA showed that the number of irrigations and the amendments statistically significantly affected the copper mobility and the organic amendment significantly influenced the iron mobility.

Graphite tail powder and liquid biofertilizer as trace elements source for ground nut

NASA Astrophysics Data System (ADS)

Hindersah, Reginawanti; Setiawati, M. Rochimi; Fitriatin, B. Natalie; Suryatama, Pujawati; Asmiran, Priyanka; Panatarani, Camellia; Joni, I. Made

2018-02-01

Utilization of graphite tail waste from the mineral beneficiation processing is very important since it contain significant amount of essential minerals which are necessary for plant growth. These mineral are required in biochemical processes and mainly play an important role as cofactor in enzymatic reaction. The objective of this research is to investigate the performance of graphite tail on supporting plant growth and yield of ground nut (Arachishypogeae L.). A field experiment has been performed to test the performance of mixed graphite tail and reduced organic matter dose. The graphite tail size were reduced to various sieved size, -80 mesh, -100 mesh and -200 mesh. The experiment was setup in randomized block design with 4 treatments and 6 replications for each treatment, while the control plot is received without graphite tail. The results demonstrated that reduced organic matter along with -200 mesh tail has potentially decreased plant height at the end of vegetative growth stage, in contrast for to -80 mesh tail amendment increased individual fresh plant biomass. Statistically, there was no change of plant nodule, individual shoot fresh and dry weight, root nodule, number of pod following any mesh of graphite tail amendment. Reducing organic matter while adding graphite tail of 5% did not change bean weight in all plot. In contrast, reduced organic matter along with 80-mesh graphite tail amendment improved the nut yield per plot. This experiment suggests that graphite tail, mainly -80 mesh graphite tail can be possibly used in legume production.

Time course for tail regression during metamorphosis of the ascidian Ciona intestinalis.

PubMed

Matsunobu, Shohei; Sasakura, Yasunori

2015-09-01

In most ascidians, the tadpole-like swimming larvae dramatically change their body-plans during metamorphosis and develop into sessile adults. The mechanisms of ascidian metamorphosis have been researched and debated for many years. Until now information on the detailed time course of the initiation and completion of each metamorphic event has not been described. One dramatic and important event in ascidian metamorphosis is tail regression, in which ascidian larvae lose their tails to adjust themselves to sessile life. In the present study, we measured the time associated with tail regression in the ascidian Ciona intestinalis. Larvae are thought to acquire competency for each metamorphic event in certain developmental periods. We show that the timing with which the competence for tail regression is acquired is determined by the time since hatching, and this timing is not affected by the timing of post-hatching events such as adhesion. Because larvae need to adhere to substrates with their papillae to induce tail regression, we measured the duration for which larvae need to remain adhered in order to initiate tail regression and the time needed for the tail to regress. Larvae acquire the ability to adhere to substrates before they acquire tail regression competence. We found that when larvae adhered before they acquired tail regression competence, they were able to remember the experience of adhesion until they acquired the ability to undergo tail regression. The time course of the events associated with tail regression provides a valuable reference, upon which the cellular and molecular mechanisms of ascidian metamorphosis can be elucidated. Copyright © 2015 Elsevier Inc. All rights reserved.

Progress in our understanding of cometary dust tails

NASA Technical Reports Server (NTRS)

Sekanina, Z.

1976-01-01

Various analytical techniques are employed to analyze observations on the character, composition, and size distribution of solid particles in cometary dust tails. Emphasized is the mechanical theory that includes solar gravitational attraction and solar radiation pressure to explain dust particle motions in cometary tails, as well as interactions between dust and plasma.

Does cortical bone thickness in the last sacral vertebra differ among tail types in primates?

PubMed

Nishimura, Abigail C; Russo, Gabrielle A

2017-04-01

The external morphology of the sacrum is demonstrably informative regarding tail type (i.e., tail presence/absence, length, and prehensility) in living and extinct primates. However, little research has focused on the relationship between tail type and internal sacral morphology, a potentially important source of functional information when fossil sacra are incomplete. Here, we determine if cortical bone cross-sectional thickness of the last sacral vertebral body differs among tail types in extant primates and can be used to reconstruct tail types in extinct primates. Cortical bone cross-sectional thickness in the last sacral vertebral body was measured from high-resolution CT scans belonging to 20 extant primate species (N = 72) assigned to tail type categories ("tailless," "nonprehensile short-tailed," "nonprehensile long-tailed," and "prehensile-tailed"). The extant dataset was then used to reconstruct the tail types for four extinct primate species. Tailless primates had significantly thinner cortical bone than tail-bearing primates. Nonprehensile short-tailed primates had significantly thinner cortical bone than nonprehensile long-tailed primates. Cortical bone cross-sectional thickness did not distinguish between prehensile-tailed and nonprehensile long-tailed taxa. Results are strongly influenced by phylogeny. Corroborating previous studies, Epipliopithecus vindobonensis was reconstructed as tailless, Archaeolemur edwardsi as long-tailed, Megaladapis grandidieri as nonprehensile short-tailed, and Palaeopropithecus kelyus as nonprehensile short-tailed or tailless. Results indicate that, in the context of phylogenetic clade, measures of cortical bone cross-sectional thickness can be used to allocate extinct primate species to tail type categories. © 2017 Wiley Periodicals, Inc.

Turbulence-driven anisotropic electron tail generation during magnetic reconnection

NASA Astrophysics Data System (ADS)

DuBois, A. M.; Scherer, A.; Almagri, A. F.; Anderson, J. K.; Pandya, M. D.; Sarff, J. S.

2018-05-01

Magnetic reconnection (MR) plays an important role in particle transport, energization, and acceleration in space, astrophysical, and laboratory plasmas. In the Madison Symmetric Torus reversed field pinch, discrete MR events release large amounts of energy from the equilibrium magnetic field, a fraction of which is transferred to electrons and ions. Previous experiments revealed an anisotropic electron tail that favors the perpendicular direction and is symmetric in the parallel. New profile measurements of x-ray emission show that the tail distribution is localized near the magnetic axis, consistent modeling of the bremsstrahlung emission. The tail appears first near the magnetic axis and then spreads radially, and the dynamics in the anisotropy and diffusion are discussed. The data presented imply that the electron tail formation likely results from a turbulent wave-particle interaction and provides evidence that high energy electrons are escaping the core-localized region through pitch angle scattering into the parallel direction, followed by stochastic parallel transport to the plasma edge. New measurements also show a strong correlation between high energy x-ray measurements and tearing mode dynamics, suggesting that the coupling between core and edge tearing modes is essential for energetic electron tail formation.

Experimental Study on Comprehensive Performance of Full Tailings Paste Filling in Jiaojia Gold Mine.

NASA Astrophysics Data System (ADS)

Zhang, Z. H.; Zou, Q. B.; Wang, P. Z.

2017-11-01

Filling mining method is the main method of modern underground mining. High concentration cementation is carried out using coarse tailing of +37 μm, and the mine has maturely used classified tailings paste filling technology. The gold mine studied on the performance of full tailings paste filling in order to maximize the use of tailings, reduce -37 μm fine tailings discharged into the tailing pond, reduce mining cost and eliminate security risks. The results show that: comprehensive index of full tailings paste filling is higher than that of classified tailings high concentration cementation filling, and the full tailings paste filling of 76% mass concentration has the best comprehensive index of slump, expansibility, yield stress and viscosity to meet the mining method requirements, which can effectively reduce the mining loss rate and dilution rate.

miTRATA: a web-based tool for microRNA Truncation and Tailing Analysis.

PubMed

Patel, Parth; Ramachandruni, S Deepthi; Kakrana, Atul; Nakano, Mayumi; Meyers, Blake C

2016-02-01

We describe miTRATA, the first web-based tool for microRNA Truncation and Tailing Analysis--the analysis of 3' modifications of microRNAs including the loss or gain of nucleotides relative to the canonical sequence. miTRATA is implemented in Python (version 3) and employs parallel processing modules to enhance its scalability when analyzing multiple small RNA (sRNA) sequencing datasets. It utilizes miRBase, currently version 21, as a source of known microRNAs for analysis. miTRATA notifies user(s) via email to download as well as visualize the results online. miTRATA's strengths lie in (i) its biologist-focused web interface, (ii) improved scalability via parallel processing and (iii) its uniqueness as a webtool to perform microRNA truncation and tailing analysis. miTRATA is developed in Python and PHP. It is available as a web-based application from https://wasabi.dbi.udel.edu/∼apps/ta/. meyers@dbi.udel.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Comprehensive Evaluation of Soil Near Uranium Tailings, Beishan City, China.

PubMed

Xun, Yan; Zhang, Xinjia; Chaoliang, Chen; Luo, Xuegang; Zhang, Yu

2018-06-01

To evaluate the impact of uranium tailings on soil composition and soil microbial, six soil samples at different distance from the uranium tailings (Beishan City, China) were collected for further analysis. Concentrations of radionuclides ( 238 U and 232 Th), heavy metals (Mn, Cd, Cr, Ni, Zn, and Pb) and organochlorine pesticide were determined by ICP-MS and GC, they were significantly higher than those of the control. And the Average Well Color Development as well as the Shannon, the Evenness, and the Simpson index were calculated to evaluate the soil microbial diversity. The carbon utilization model of soil microbial community was also analyzed by Biolog-eco. All results indicated that uranium tailings leaded to excessive radionuclides and heavy metals, and decreased the diversity of the soil microbial community. Our study will provide a valuable basis for soil quality evaluation around uranium tailing repositories and lay a foundation for the management and recovery of uranium tailings.

Vegetation successfully prevents oxidization of sulfide minerals in mine tailings.

PubMed

Li, Yang; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

2016-07-15

The oxidization of metal sulfide in tailings causes acid mine drainage. However, it remains unclear whether vegetation prevents the oxidization of metal sulfides. The oxidization characteristics and microbial indices of the tailings in the presence of various plant species were investigated to explore the effects of vegetation on the oxidization of sulfide minerals in tailings. The pH, reducing sulfur, free iron oxides (Fed), chemical oxygen consumption (COC) and biological oxygen consumption (BOC) were measured. Key iron- and sulfur-oxidizing bacteria (Acidithiobacillus spp., Leptospirillum spp. and Thiobacillus spp.) were quantified using real-time PCR. The results indicate that vegetation growing on tailings can effectively prevent the oxidization of sulfide minerals in tailings. A higher pH and reducing-sulfur content and lower Fed were observed in the 0-30 cm depth interval in the presence of vegetation compared to bare tailings (BT). The COC gradually decreased with depth in all of the soil profiles; specifically, the COC rapidly decreased in the 10-20 cm interval in the presence of vegetation but gradually decreased in the BT profiles. Imperata cylindrica (IC) and Chrysopogon zizanoides (CZ) profiles contained the highest BOC in the 10-20 cm interval. The abundance of key iron- and sulfur-oxidizing bacteria in the vegetated tailings were significantly lower than in the BT; in particular, IC was associated with the lowest iron- and sulfur-oxidizing bacterial abundance. In conclusion, vegetation successfully prevented the oxidization of sulfide minerals in the tailings, and Imperata cylindrica is the most effective in reducing the number of iron- and sulfur-oxidizing bacteria and helped to prevent the oxidization of sulfide minerals in the long term. Copyright © 2016 Elsevier Ltd. All rights reserved.

Poly A tail length analysis of in vitro transcribed mRNA by LC-MS.

PubMed

Beverly, Michael; Hagen, Caitlin; Slack, Olga

2018-02-01

The 3'-polyadenosine (poly A) tail of in vitro transcribed (IVT) mRNA was studied using liquid chromatography coupled to mass spectrometry (LC-MS). Poly A tails were cleaved from the mRNA using ribonuclease T1 followed by isolation with dT magnetic beads. Extracted tails were then analyzed by LC-MS which provided tail length information at single-nucleotide resolution. A 2100-nt mRNA with plasmid-encoded poly A tail lengths of either 27, 64, 100, or 117 nucleotides was used for these studies as enzymatically added poly A tails showed significant length heterogeneity. The number of As observed in the tails closely matched Sanger sequencing results of the DNA template, and even minor plasmid populations with sequence variations were detected. When the plasmid sequence contained a discreet number of poly As in the tail, analysis revealed a distribution that included tails longer than the encoded tail lengths. These observations were consistent with transcriptional slippage of T7 RNAP taking place within a poly A sequence. The type of RNAP did not alter the observed tail distribution, and comparison of T3, T7, and SP6 showed all three RNAPs produced equivalent tail length distributions. The addition of a sequence at the 3' end of the poly A tail did, however, produce narrower tail length distributions which supports a previously described model of slippage where the 3' end can be locked in place by having a G or C after the poly nucleotide region. Graphical abstract Determination of mRNA poly A tail length using magnetic beads and LC-MS.

14 CFR 25.481 - Tail-down landing conditions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tail-down landing conditions. 25.481... landing conditions. (a) In the tail-down attitude, the airplane is assumed to contact the ground at... prescribed in § 25.473 with— (1) V L 1 equal to V S 0 (TAS) at the appropriate landing weight and in standard...

Prehensile and non-prehensile tails among syngnathid fishes: what's the difference?

PubMed

Neutens, Céline; de Dobbelaer, Bart; Claes, Peter; Adriaens, Dominique

2017-02-01

All syngnathid fishes are characterized by a tail with a vertebral column that is surrounded by dermal Plates - four per vertebra. Seahorses and pipehorses have prehensile tails, a unique characteristic among teleosts that allows them to grasp and hold onto substrates. Pipefishes, in contrast, possess a more rigid tail. Previous research (Neutens et al., 2014) showed a wide range of variation within the skeletal morphology of different members in the syngnathid family. The goal of this study is to explore whether the diversity in the three-dimensional (3D) shape of different tail types reflects grasping performance, and to what degree grasping tails occupy a different and more constrained diversity. For this, a 3D morphometrical analysis based on surfaces was performed. Four different analyses were performed on the tail skeleton of nine species exhibiting different levels of tail grasping capacities (four pipehorse, three seahorse, one pipefish and one seadragon species) to examine the intra-individual variation across the anteroposterior and dorso-ventral axis. In the two interspecific analyses, all vertebrae and all dermal plates were mutually compared. Overall, intra-individual variation was larger in species with a prehensile tail. The analysis on the vertebrae showed differences in the length and orientation of the hemal spine as well as the inclination angle between the anterior and posterior surface of the vertebral body. This was observed at an intra-individual level across the anteroposterior axis in prehensile species and at an inter-individual level between prehensile and non-prehensile species. Across the anteroposterior axis in prehensile tails, the overall shape of the plates changes from rectangular at the anterior end to square at the posterior end. Across the dorso-ventral axis, the ventral dermal plates carry a significantly longer caudal spine than the dorsal ones in all prehensile-tailed species. It can therefore be concluded that prehensile

Radiation data input for the design of dry or semi-dry U tailings disposal.

PubMed

Kvasnicka, J

1986-09-01

Before discussion of design criteria for the handling of dry or semi-dry tailings, it is necessary to obtain an insight into the radiation levels associated with the tailings particles and to study the basic physical properties of dry tailings. This article presents the experimental results of assessing Ra and specific alpha-activity distribution with respect to particle size of the Ranger (RUM) and Nabarlek (QML) uranium mines dry tailings samples. The variation of Rn emanation coefficient versus particle size of dry tailings has also been measured. The nuclear-track detection technique, gamma spectrometry and alpha counting were used for the above measurements. Surface Rn flux from the hypothetical Nabarlek semi-infinite dry tailings pile is 32 Bq m-2 s-1 and the Rn flux for Ranger is 10 Bq m-2 s-1. The theoretical exposure rates for 1 m above these hypothetical tailings piles are 0.95 microC kg-1 h-1 and 0.28 microC kg-1 h-1, respectively. The derived air alpha-contamination limits (DAAC) for the tailings dust were calculated to be 1.2 Bq m-3 for workers and 0.034 Bq m-3 for a member of the public. The limit for workers corresponds to the air tailings dust concentration of 0.79 mg m-3 for QML tailings and 2.2 mg m-3 for RUM tailings. The DAAC limit for the public corresponds to the air tailings dust concentration of 0.022 mg m-3 for QML tailings and 0.064 mg m-3 for RUM tailings.

Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings.

PubMed

Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A H

2015-01-01

Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal.

Study on the Influence of Elevation of Tailing Dam on Stability

NASA Astrophysics Data System (ADS)

Wan, Shuai; Wang, Kun; Kong, Songtao; Zhao, Runan; Lan, Ying; Zhang, Run

2017-12-01

This paper takes Yunnan as the object of a tailing, by theoretical analysis and numerical calculation method of the effect of seismic load effect of elevation on the stability of the tailing, to analyse the stability of two point driven safety factor and liquefaction area. The Bishop method is adopted to simplify the calculation of dynamic safety factor and liquefaction area analysis using comparison method of shear stress to analyse liquefaction, so we obtained the influence of elevation on the stability of the tailing. Under the earthquake, with the elevation increased, the safety coefficient of dam body decreases, shallow tailing are susceptible to liquefy. Liquefaction area mainly concentrated in the bank below the water surface, to improve the scientific basis for the design and safety management of the tailing.

Evaluation of pyritic mine tailings as a plant growth substrate.

PubMed

Roseby, Stuart J; Kopittke, Peter M; Mulligan, David R; Menzies, Neal W

2017-10-01

At the Kidston gold mine, Australia, the direct establishment of vegetation on tailings was considered as an alternative to the use of a waste rock cover. The tailings acid/base account was used to predict plant growth limitation by acidity, and thus methods capable of identifying tailings that would acidify to pH 4.5 or lower were sought. Total S was found to be poorly correlated with acid-generating sulfide, and total C was poorly correlated with acid-neutralizing carbonate, precluding the use of readily determined total S and C as predictors of net acid generation. Therefore, the selected approach used assessment of sulfide content as a predictor of acid generation, and carbonate content as a measure of the acid-neutralizing capacity available at pH 5 and above. Using this approach, the majority of tailings (67%) were found to be non-acid generating. However, areas of potentially acid-generating tailings were randomly distributed across the dam, and could only be located by intensive sampling. The limitations imposed by the large sample numbers, and costly analysis of sulfide and carbonate, make it impractical to identify and ameliorate acid-generating areas prior to vegetation establishment. However, as only a small proportion of the tailings will acidify, a strategy of re-treating acid areas following oxidation is suggested. The findings of the present study will assist in the selection of appropriate methods for the prediction of net acid generation, particularly where more conservative measurements are required to allow vegetation to be established directly in tailings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Engineering assessment of inactive uranium mill tailings: Maybell Site, Maybell, Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1981-09-01

Ford, Bacon and Davis Utah Inc. has reevaluated the Maybell site in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Maybell, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 2.6 million dry tons of tailings at the Maybell sitemore » constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The two alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material (Option I), to disposal of the tailings in a nearby open pit mine and decontamination of the tailings site (Option II). Cost estimates for the two options are about $11,700,000 for stabilization in-place and about $22,700,000 for disposal within a distance of 2 mi. Three principal alternatives for the reprocessing of the Maybell tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $125 and $165/lb of U/sub 3/O/sub 8/ by heap leach and conventional plant processes, respectively. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery is not economically attractive at present.« less

Notochord-derived hedgehog is essential for tail regeneration in Xenopus tadpole.

PubMed

Taniguchi, Yuka; Watanabe, Kenji; Mochii, Makoto

2014-06-18

Appendage regeneration in amphibians is regulated by the combinatorial actions of signaling molecules. The requirement of molecules secreted from specific tissues is reflected by the observation that the whole process of regeneration can be inhibited if a certain tissue is removed from the amputated stump. Interestingly, urodeles and anurans show different tissue dependencies during tail regeneration. The spinal cord is essential for tail regeneration in urodele but not in anuran larva, whereas the notochord but not the spinal cord is essential for tail regeneration in anuran tadpoles. Sonic hedgehog is one of the signaling molecules responsible for such phenomenon in axolotl, as hedgehog signaling is essential for overall tail regeneration and sonic hedgehog is exclusively expressed in the spinal cord. In order to know whether hedgehog signaling is involved in the molecular mechanism underlying the inconsistent tissue dependency for tail regeneration between anurans and urodeles, we investigated expression of hedgehog signal-related genes in the regenerating tail of Xenopus tadpole and examined the effect of the hedgehog signal inhibitor, cyclopamine, on the tail regeneration. In Xenopus, sonic hedgehog is expressed exclusively in the notochord but not in the spinal cord of the regenerate. Overall regeneration was severely impaired in cyclopamine-treated tadpoles. Notochord maturation in the regenerate, including cell alignment and vacuolation, and myofiber formation were inhibited. Proliferation of spinal cord cells in the neural ampulla and of mesenchymal cells was also impaired. As in the axolotl, hedgehog signaling is required for multiple steps in tail regeneration in the Xenopus tadpole, although the location of the Shh source is quite different between the two species. This difference in Shh localization is the likely basis for the differing tissue requirement for tail regeneration between urodeles and anurans.

Notochord-derived hedgehog is essential for tail regeneration in Xenopus tadpole

PubMed Central

2014-01-01

Background Appendage regeneration in amphibians is regulated by the combinatorial actions of signaling molecules. The requirement of molecules secreted from specific tissues is reflected by the observation that the whole process of regeneration can be inhibited if a certain tissue is removed from the amputated stump. Interestingly, urodeles and anurans show different tissue dependencies during tail regeneration. The spinal cord is essential for tail regeneration in urodele but not in anuran larva, whereas the notochord but not the spinal cord is essential for tail regeneration in anuran tadpoles. Sonic hedgehog is one of the signaling molecules responsible for such phenomenon in axolotl, as hedgehog signaling is essential for overall tail regeneration and sonic hedgehog is exclusively expressed in the spinal cord. In order to know whether hedgehog signaling is involved in the molecular mechanism underlying the inconsistent tissue dependency for tail regeneration between anurans and urodeles, we investigated expression of hedgehog signal-related genes in the regenerating tail of Xenopus tadpole and examined the effect of the hedgehog signal inhibitor, cyclopamine, on the tail regeneration. Results In Xenopus, sonic hedgehog is expressed exclusively in the notochord but not in the spinal cord of the regenerate. Overall regeneration was severely impaired in cyclopamine-treated tadpoles. Notochord maturation in the regenerate, including cell alignment and vacuolation, and myofiber formation were inhibited. Proliferation of spinal cord cells in the neural ampulla and of mesenchymal cells was also impaired. Conclusion As in the axolotl, hedgehog signaling is required for multiple steps in tail regeneration in the Xenopus tadpole, although the location of the Shh source is quite different between the two species. This difference in Shh localization is the likely basis for the differing tissue requirement for tail regeneration between urodeles and anurans. PMID:24941877

OPERATIONS TOGGLE, ARBOR and BEDROCK Events: DIAMOND SCULLS, DIDO QUEEN, HUSKY ACE, MING BLADE, HYBLA FAIR and DINING CAR, 20 July 1972 - 5 April 1975

DTIC Science & Technology

1987-11-30

1975 to study weapons effects . All six were tunnel-type nuclear tests. The following table summarizes data on these events: OPERATION TOGGLE ARBOR...194 nuclear device tests conducted, 161 were for weapons related or effects purposes, and 33 were safety ex- periments. An additional 22 nuclear...on 25 April 1962 until the last atmospheric test on 4 November 1962, 40 weapons development and weapons effects tests were conducted as part of

Bacterial diversity and composition of an alkaline uranium mine tailings-water interface.

PubMed

Khan, Nurul H; Bondici, Viorica F; Medihala, Prabhakara G; Lawrence, John R; Wolfaardt, Gideon M; Warner, Jeff; Korber, Darren R

2013-10-01

The microbial diversity and biogeochemical potential associated with a northern Saskatchewan uranium mine water-tailings interface was examined using culture-dependent and -independent techniques. Morphologically-distinct colonies from uranium mine water-tailings and a reference lake (MC) obtained using selective and non-selective media were selected for 16S rRNA gene sequencing and identification, revealing that culturable organisms from the uranium tailings interface were dominated by Firmicutes and Betaproteobacteria; whereas, MC organisms mainly consisted of Bacteroidetes and Gammaproteobacteria. Ion Torrent (IT) 16S rRNA metagenomic analysis carried out on extracted DNA from tailings and MC interfaces demonstrated the dominance of Firmicutes in both of the systems. Overall, the tailings-water interface environment harbored a distinct bacterial community relative to the MC, reflective of the ambient conditions (i.e., total dissolved solids, pH, salinity, conductivity, heavy metals) dominating the uranium tailings system. Significant correlations among the physicochemical data and the major bacterial groups present in the tailings and MC were also observed. Presence of sulfate reducing bacteria demonstrated by culture-dependent analyses and the dominance of Desulfosporosinus spp. indicated by Ion Torrent analyses within the tailings-water interface suggests the existence of anaerobic microenvironments along with the potential for reductive metabolic processes.

Asymmetric breathing motions of nucleosomal DNA and the role of histone tails

NASA Astrophysics Data System (ADS)

Chakraborty, Kaushik; Loverde, Sharon M.

2017-08-01

The most important packing unit of DNA in the eukaryotic cell is the nucleosome. It undergoes large-scale structural re-arrangements during different cell cycles. For example, the disassembly of the nucleosome is one of the key steps for DNA replication, whereas reassembly occurs after replication. Thus, conformational dynamics of the nucleosome is crucial for different DNA metabolic processes. We perform three different sets of atomistic molecular dynamics simulations of the nucleosome core particle at varying degrees of salt conditions for a total of 0.7 μs simulation time. We find that the conformational dynamics of the nucleosomal DNA tails are oppositely correlated from each other during the initial breathing motions. Furthermore, the strength of the interaction of the nucleosomal DNA tail with the neighboring H2A histone tail modulates the conformational state of the nucleosomal DNA tail. With increasing salt concentration, the degree of asymmetry in the conformation of the nucleosomal DNA tails decreases as both tails tend to unwrap. This direct correlation between the asymmetric breathing motions of the DNA tails and the H2A histone tails, and its decrease at higher salt concentrations, may play a significant role in the molecular pathway of unwrapping.

Determination of the reaction rate coefficient of sulphide mine tailings deposited under water.

PubMed

Awoh, Akué Sylvette; Mbonimpa, Mamert; Bussière, Bruno

2013-10-15

The efficiency of a water cover to limit dissolved oxygen (DO) availability to underlying acid-generating mine tailings can be assessed by calculating the DO flux at the tailings-water interface. Fick's equations, which are generally used to calculate this flux, require knowing the effective DO diffusion coefficient (Dw) and the reaction (consumption) rate coefficient (Kr) of the tailings, or the DO concentration profile. Whereas Dw can be accurately estimated, few studies have measured the parameter Kr for submerged sulphide tailings. The objective of this study was to determine Kr for underwater sulphide tailings in a laboratory experiment. Samples of sulphide mine tailings (an approximately 6 cm layer) were placed in a cell under a water cover (approximately 2 cm) maintained at constant DO concentration. Two tailings were studied: TA1 with high sulphide content (83% pyrite) and TA2 with low sulphide content (2.8% pyrite). DO concentration was measured with a microelectrode at various depths above and below the tailings-water interface at 1 mm intervals. Results indicate that steady-state condition was rapidly attained. As expected, a diffusive boundary layer (DBL) was observed in all cases. An iterative back-calculation process using the numerical code POLLUTEv6 and taking the DBL into account provided the Kr values used to match calculated and experimental concentration profiles. Kr obtained for tailings TA1 and TA2 was about 80 d(-1) and 6.5 d(-1), respectively. For comparison purposes, Kr obtained from cell tests on tailings TA1 was lower than Kr calculated from the sulphate production rate obtained from shake-flask tests. Steady-state DO flux at the water-tailings interface was then calculated with POLLUTEv6 using tailings characteristics Dw and Kr. For the tested conditions, DO flux ranged from 608 to 758 mg O2/m(2)/d for tailings TA1 and from 177 to 221 mg O2/m(2)/d for tailings TA2. The impact of placing a protective layer of inert material over

On the mechanism of ray closure in comet tails

NASA Astrophysics Data System (ADS)

Ershkovich, A. I.

The folding phenomenon of comet tail rays is explained by means of an electric drift due to convectional electric fields. This mechanism results in an angular rate of closure which reduces to that obtained by Ness and Donn (1966) if the velocity profile across the tail is linear and the plasma conductivity is ideal. Observations of both the ray closure and the disconnection events point to the phenomenon of anomalous resistivity. Magnetic fields of about 30-40 gammas in the coma and of 10 gammas in the distant tail (at 1 AU) are estimated from the MHD momentum equation.

Engineering assessment of inactive uranium mill tailings, Durango Site, Durango, Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-06-01

Ford, Bacon and Davis Utah Inc. has reevaluated the Durango site in order to revise the November 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Durango, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the nearly 1.6 million tons of tailings at the Durango sitemore » constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through IV). Cost estimates for the seven options range from about $10,700,000 for stabilization in-place, to about $21,800,000 for disposal at a distance of about 10 mi. Three principal alternatives for the reprocessing of the Durango tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $30/lb U/sub 3/O/sub 8/ by either heap leach or conventional plant processes.« less

The microbiology of oil sands tailings: past, present, future.

PubMed

Foght, Julia M; Gieg, Lisa M; Siddique, Tariq

2017-05-01

Surface mining of enormous oil sands deposits in northeastern Alberta, Canada since 1967 has contributed greatly to Canada's economy but has also received negative international attention due largely to environmental concerns and challenges. Not only have microbes profoundly affected the composition and behavior of this petroleum resource over geological time, they currently influence the management of semi-solid tailings in oil sands tailings ponds (OSTPs) and tailings reclamation. Historically, microbial impacts on OSTPs were generally discounted, but next-generation sequencing and biogeochemical studies have revealed unexpectedly diverse indigenous communities and expanded our fundamental understanding of anaerobic microbial functions. OSTPs that experienced different processing and management histories have developed distinct microbial communities that influence the behavior and reclamation of the tailings stored therein. In particular, the interactions of Deltaproteobacteria and Firmicutes with methanogenic archaea impact greenhouse gas emissions, sulfur cycling, pore water toxicity, sediment biogeochemistry and densification, water usage and the trajectory of long-term mine waste reclamation. This review summarizes historical data; synthesizes current understanding of microbial diversity and activities in situ and in vitro; predicts microbial effects on tailings remediation and reclamation; and highlights knowledge gaps for future research. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Rapid green synthesis of silver nanoparticles by aqueous extract of seeds of Nyctanthes arbor-tristis

NASA Astrophysics Data System (ADS)

Basu, Shibani; Maji, Priyankar; Ganguly, Jhuma

2016-01-01

The present study explores that the aqueous extract of the seeds of Nyctanthes arbor-tristis (aka night jasmine) is very efficient for the synthesis of stable AgNPs from aqueous solution of AgNO3. The extract acts as both reducing (from Ag+ to Ag0) and capping agent in the aqueous phase. The constituents in extract are mainly biomolecules like carbohydrates and phenolic compounds, which are responsible for the preparation of stable AgNPs within 20 min of reaction time at 25 °C using without any severe conditions. The synthesized silver nanoparticles were characterized with UV-Visible spectroscopy, FT-IR, XRD and SEM. UV-Vis spectroscopy analysis showed peak at 420 nm, which corresponds to the surface plasmon resonance of AgNPs. XRD results showed peaks at (111), (200), (220), which confirmed the presence of AgNPs with face-centered cubic structure. The uniform spherical nature of the AgNPs and size (between 50 and 80 nm) were further confirmed by SEM analysis.

DSCAM-mediated control of dendritic and axonal arbor outgrowth enforces tiling and inhibits synaptic plasticity

PubMed Central

Simmons, Aaron B.; Bloomsburg, Samuel J.; Sukeena, Joshua M.; Miller, Calvin J.; Ortega-Burgos, Yohaniz; Borghuis, Bart G.

2017-01-01

Mature mammalian neurons have a limited ability to extend neurites and make new synaptic connections, but the mechanisms that inhibit such plasticity remain poorly understood. Here, we report that OFF-type retinal bipolar cells in mice are an exception to this rule, as they form new anatomical connections within their tiled dendritic fields well after retinal maturity. The Down syndrome cell-adhesion molecule (Dscam) confines these anatomical rearrangements within the normal tiled fields, as conditional deletion of the gene permits extension of dendrite and axon arbors beyond these borders. Dscam deletion in the mature retina results in expanded dendritic fields and increased cone photoreceptor contacts, demonstrating that DSCAM actively inhibits circuit-level plasticity. Electrophysiological recordings from Dscam−/− OFF bipolar cells showed enlarged visual receptive fields, demonstrating that expanded dendritic territories comprise functional synapses. Our results identify cell-adhesion molecule-mediated inhibition as a regulator of circuit-level neuronal plasticity in the adult retina. PMID:29114051

Microbial metabolism alters pore water chemistry and increases consolidation of oil sands tailings.

PubMed

Arkell, Nicholas; Kuznetsov, Petr; Kuznetsova, Alsu; Foght, Julia M; Siddique, Tariq

2015-01-01

Tailings produced during bitumen extraction from surface-mined oil sands ores (tar sands) comprise an aqueous suspension of clay particles that remain dispersed for decades in tailings ponds. Slow consolidation of the clays hinders water recovery for reuse and retards volume reduction, thereby increasing the environmental footprint of tailings ponds. We investigated mechanisms of tailings consolidation and revealed that indigenous anaerobic microorganisms altered porewater chemistry by producing CO and CH during metabolism of acetate added as a labile carbon amendment. Entrapped biogenic CO decreased tailings pH, thereby increasing calcium (Ca) and magnesium (Mg) cations and bicarbonate (HCO) concentrations in the porewater through dissolution of carbonate minerals. Soluble ions increased the porewater ionic strength, which, with higher exchangeable Ca and Mg, decreased the diffuse double layer of clays and increased consolidation of tailings compared with unamended tailings in which little microbial activity was observed. These results are relevant to effective tailings pond management strategies. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Tail dependence and information flow: Evidence from international equity markets

NASA Astrophysics Data System (ADS)

Al Rahahleh, Naseem; Bhatti, M. Ishaq; Adeinat, Iman

2017-05-01

Bhatti and Nguyen (2012) used the copula approach to measure the tail dependence between a number of international markets. They observed that some country pairs exhibit only left-tail dependence whereas others show only right-tail. However, the flow of information from uni-dimensional (one-tail) to bi-dimensional (two-tails) between various markets was not accounted for. In this study, we address the flow of information of this nature by using the dynamic conditional correlation (DCC-GARCH) model. More specifically, we use various versions of the DCC models to explain the nexus between the information flow of international equity and to explain the stochastic forward vs. backward dynamics of financial markets based on data for a 15-year period comprising 3,782 observations. We observed that the information flow between the US and Hong Kong markets and between the US and Australian markets are bi-directional. We also observed that the DCC model captures a wider co-movement structure and inter-connectedness compared to the symmetric Joe-Clayton copula.

Bacterial and chemical oxidation of pyritic mine tailings at low temperatures

NASA Astrophysics Data System (ADS)

Elberling, Bo; Schippers, Axel; Sand, Wolfgang

2000-02-01

Microbial and chemical sulfide oxidation activity and oxygen consumption was investigated in the active layer of pyritic mine tailings at Nanisivik Mine, located in a permafrost area on Baffin Island in northern Canada. Samples of tailings were collected up to a depth of 60 cm in mid-August 1998 at 4 sites, for which the metabolic activity of sulfur- and iron-oxidizing leaching bacteria besides the chemical pyrite oxidation activity were measured on 39 tailings samples and 7 samples from a natural pyritic site by calorimetry. The tailings of varying age and water content were deposited under alkaline conditions. In situ oxygen uptake rates were measured at the tailings surface every third day, prior to sampling. In addition, cell counts of iron(II), sulfur, and thiosulfate oxidizing, lithotrophic bacteria and chemoorganotrophic microorganisms were determined quantitatively by the most-probable-number technique or by agar-plating. Results show consistent pyrite oxidation rates based on in situ oxygen uptake rates, and laboratory heat output measurements. Litho- and organotrophic bacteria were found in the tailings. Calorimetric measurements revealed that the present bacterial activity is responsible for approximately one third of the ongoing oxidation. Although leaching bacteria have previously been found in the Arctic, this study is the first to prove the significance of bacterial activity in the overall pollution resulting from tailings deposited in the Arctic.

Element flows associated with marine shore mine tailings deposits.

PubMed

Dold, Bernhard

2006-02-01

From 1938 until 1975, flotation tailings from the Potrerillos--El Salvador mining district (porphyry copper deposits) were discharged into the El Salado valley and transported in suspension to the sea at Chaliaral Bay, Atacama Desert, northern Chile. Over 220 Mt of tailings, averaging 0.8 +/- 0.25 wt % of pyrite, were deposited into the bay, resulting in over a 1 kilometer seaward displacement of the shoreline and an estimated 10-15 m thick tailings accumulation covering a approximately 4 km2 surface area. The Chaniaral case was classified by the United Nations Environmental Programme (UNEP) in 1983 as one of the most serious cases of marine contamination in the Pacific area. Since 1975, the tailings have been exposed to oxidation, resulting in a 70-188 cm thick low-pH (2.6-4) oxidation zone at the top with liberation of divalent metal cations, such as Cu2+, Ni2+, and Zn2+ (up to 2265 mg/L, 18.1 mg/L, and 20.3 mg/ L, respectively). Evaporation-induced transport capillarity led to metal enrichment atthe tailings surface (e.g. up to 2.4% Cu) in the form of secondary chlorides and/or sulfates (dominated by eriochalcite [CuCl.H2O] and halite). These, mainly water-soluble, secondary minerals were exposed to eolian transport in the direction of the Village of Chañaral by the predominant W-SW winds. Two element-flow directions (toward the tailings surface, via capillarity, and toward the sea) and two element groups with different geochemical behaviors (cations such as Cu, Zn, Ni, and oxyanions such as As and Mo) could be distinguished. It can be postulated, that the sea is mainly affected by the following: As, Mo, Cu, and Zn contamination, which were liberated from the oxidation zone from the tailings and mobilized through the tidal cycle, and by Cu and Zn from the subsurface waters flowing in the El Salado valley (up to 19 mg/L and 12 mg/L Zn, respectively), transported as chloro complexes at neutral pH.

Computational Investigation and Validation of Twin-Tail Buffet Response Including Dynamics and Control

NASA Technical Reports Server (NTRS)

Kandil, Osama A.

1998-01-01

Multidisciplinary tools for prediction of single rectangular-tail buffet are extended to single swept-back-tail buffet in transonic-speed flow, and multidisciplinary tools for prediction and control of twin-tail buffet are developed and presented. The configuration model consists of a sharp-edged delta wing with single or twin tails that are oriented normal to the wing surface. The tails are treated as cantilevered beams fixed at the root and allowed to oscillate in both bending and torsion. This complex multidisciplinary problem is solved sequentially using three sets of equations on a dynamic single or multi-block grid structure. The first set is the unsteady, compressible, Reynolds-averaged Navier-Stokes equations which are used for obtaining the flow field vector and the aerodynamic loads on the tails. The Navier-Stokes equations are solved accurately in time using the implicit, upwind, flux-difference splitting, finite volume scheme. The second set is the coupled bending and torsion aeroelastic equations of cantilevered beams which are used for obtaining the bending and torsion deflections of the tails. The aeroelastic equations'are solved accurately in time using, a fifth-order-accurate Runge-Kutta scheme. The third set is the grid-displacement equations and the rigid-body dynamics equations, which are used for updating the grid coordinates due to the tail deflections and rigid-body motions. The tail-buffet phenomenon is predicted for highly-swept, single vertical tail placed at the plane of geometric symmetry, and for highly-swept, vertical twin tails placed at three different spanwise separation distances. The investigation demonstrates the effects of structural inertial coupling and uncoupling of the bending and torsion modes of vibration, spanwise positions of the twin-tail, angle of attack, and pitching and rolling dynamic motions of the configuration model on the tail buffet loading and response. The fundamental issue of twin-tail buffet alleviation is

Arboreal Day Geckos (Phelsuma madagascariensis) Differentially Modulate Fore- and Hind Limb Kinematics in Response to Changes in Habitat Structure

PubMed Central

Zhuang, Mingna V.; Higham, Timothy E.

2016-01-01

By using adhesion, geckos can move through incredibly challenging habitats. However, continually changing terrain may necessitate modulation of the adhesive apparatus in order to maximize its effectiveness over a range of challenges. Behaviorally modulating how the adhesive system is applied can occur by altering the alignment of the foot relative to the long axis of the body and/or the angles between the digits (interdigital angle). Given the directionality of the adhesive system, geckos likely vary the application of the system via these mechanisms as they run. We quantified 3D movements (using high-speed video) of the day gecko, Phelsuma madagascariensis, running on a range of ecologically relevant inclines (0°, 45°, 90°) and perch diameters (1.5 cm, 10 cm and broad). We measured the instantaneous sum of interdigital angles and foot alignment relative to the body, as well as other kinematic variables, throughout each stride and across treatments. Modulation of foot alignment at 45° and 90° was similar between the forelimb and hind limb, but differed at 0°, suggesting that P. madagascariensis is able to exert an adhesive force using multiple strategies. Both the sum of interdigital angles and alignment in the fore- and hind foot were modulated. Differences in modulation between the limbs are likely related to the underlying morphology. The modulation of interdigital angle and foot alignment suggests that aspects other than the mechanism of adhesion, such as joint morphology, are important for arboreal movement in geckos. Our study of foot usage in arboreal locomotion reveals patterns that may be widespread across pad-bearing lizards. In addition to understanding the constraints exerted by the adhesive apparatus, we highlight how biomechanical traits may respond to the evolution of novel adaptations and morphologies. PMID:27145027

Search behavior of arboreal insectivorous migrants at gulf coast stopover sites in spring

USGS Publications Warehouse

Chen, Chao-Chieh; Barrow, W.C.; Ouchley, K.; Hamilton, R.B.

2011-01-01

Search behavior of arboreal insectivorous migrants was studied at three stopover sites along the northern coast of the Gulf of Mexico during spring migrations, 1993–1995. We examined if search behavior was affected by phylogeny, or by environmental factors. A sequence of search movements (hop, flutter, or flight) in a foraging bout was recorded for each migrant encountered. Search rate, frequency, and distance of movements were calculated for each species. Search rate was positively correlated with proportion of hop, but negatively correlated to flight distance. Hop distance was positively correlated to tarsus length, as was flight distance to wing length for the 31 species of migrants. Cluster analysis indicated closely related species generally have similar foraging modes, which range from “sit-and-wait” of flycatchers to “widely foraging” of warblers. Migrants tended to use more hops in dense vegetation, but more flights in areas with sparse vegetation. Migrants also used more flights when foraging in mixed-species flocks and during periods of high migrant density. Logistic models indicated warblers were more influenced by environmental factors than vireos, possibly because warblers are near-perch searchers and more affected by these factors.

A distributed algorithm to maintain and repair the trail networks of arboreal ants.

PubMed

Chandrasekhar, Arjun; Gordon, Deborah M; Navlakha, Saket

2018-06-18

We study how the arboreal turtle ant (Cephalotes goniodontus) solves a fundamental computing problem: maintaining a trail network and finding alternative paths to route around broken links in the network. Turtle ants form a routing backbone of foraging trails linking several nests and temporary food sources. This species travels only in the trees, so their foraging trails are constrained to lie on a natural graph formed by overlapping branches and vines in the tangled canopy. Links between branches, however, can be ephemeral, easily destroyed by wind, rain, or animal movements. Here we report a biologically feasible distributed algorithm, parameterized using field data, that can plausibly describe how turtle ants maintain the routing backbone and find alternative paths to circumvent broken links in the backbone. We validate the ability of this probabilistic algorithm to circumvent simulated breaks in synthetic and real-world networks, and we derive an analytic explanation for why certain features are crucial to improve the algorithm's success. Our proposed algorithm uses fewer computational resources than common distributed graph search algorithms, and thus may be useful in other domains, such as for swarm computing or for coordinating molecular robots.

The fecundity of fork-tailed threadfin bream (Nemipterus furcosus) in Bangka, Bangka Belitung

NASA Astrophysics Data System (ADS)

Utami, E.; Safitriyani, E.; Gatra Persada, Leo

2018-04-01

Fork-tailed threadfin bream (Nemipterus furcosus) is one of important economic fishes in Bangka. The sustainability of fork-tailed threadfin bream is threatened by degradation of natural habitat. Information of reproductive is needed for further management. The objective of this study was to examine fecundity of fork-tailed threadfin bream. The mean values of temperature was 28.83 ± 0,37°C, respectively. Sex ratio during sampling showed that female fork-tailed threadfin bream greater than male population. Berried female fork-tailed threadfin bream found from March until November. The greatest number of berried female fork-tailed threadfin bream showed in July with berried female value of 25. Fork-tailed threadfin bream fecundity was 19951 and 66628, respectively. The fecundity data can be used to access the reproductive potential of fish stock and also as an assessment on stock size of their natural population.

Selection of arboreal termitaria for nesting by cooperatively breeding Micronesian Kingfishers Todiramphus cinnamominus reichenbachii

USGS Publications Warehouse

Kesler, Dylan C.; Haig, Susan M.

2005-01-01

Limited nest-site availability appears to be an important factor in the evolution of delayed dispersal and cooperative breeding in some cavity-nesting species. The cooperatively breeding Pohnpei subspecies of Micronesian Kingfisher Todiramphus cinnamominus reichenbachii excavates nest cavities from the nests of arboreal termites Nasutitermes spp., or termitaria. In this first published description of nest-sites for this subspecies, we used surveys, remote sensing and radiotelemetry to evaluate the relationship between nest-site availability and co-operation. Results illustrate that nest termitaria are higher in the forest canopy, larger in volume and occur in areas with more contiguous canopy cover than unused termitaria. Nest termitaria were selected independently of the proximity to forest edges and territory boundaries, and we found no difference in characteristics of termitaria used by cooperative groups and breeding pairs. Logistic regression modelling indicated that termitaria with nest-like characteristics were not limited in abundance, suggesting that neither the prospects of inheriting nesting resources nor limited nest-site abundance are probable explanations for delayed dispersal in the Pohnpei subspecies of Micronesian Kingfisher.

Characteristics of the tail of Comet Giacobini-Zinner

NASA Technical Reports Server (NTRS)

Scarf, F. L.

1986-01-01

The physical structure and characteristics of the Comet Giacobini-Zinner tail are described. Variations in the vector B-field configuration, the electron distribution function, the energetic ion population, and the electromagnetic and electrostatic plasma wave spectra are analyzed. The ICE detected a two-lobe magnetic field configuration and a narrow central plasma sheet. Additional analyses proposed for the Giacobini-Zinner tail data are discussed.

Ferric minerals and organic matter change arsenic speciation in copper mine tailings.

PubMed

Wang, Peng; Liu, Yunjia; Menzies, Neal W; Wehr, J Bernhard; de Jonge, Martin D; Howard, Daryl L; Kopittke, Peter M; Huang, Longbin

2016-11-01

Arsenic (As) is commonly associated with Cu ore minerals, with the resultant risk that As can be released offsite from mine tailings. We used synchrotron-based fluorescence X-ray absorption near-edge spectroscopy (XANES) imaging to provide in situ, laterally-resolved speciation of As within tailings which differed in magnetite content (5-12%) and organic matter content (0-5%). Although the total As content was lower in tailings with low magnetite (LM), the soluble (pore water) As was actually 7-times higher in LM tailings than in high magnetite (HM) tailings. Additionally, amendment with 5% sugarcane mulch residues (SMR) (for revegetation) further increased soluble As due to the dissolution and oxidation of arsenopyrite or orpiment. Indeed, in HM tailings, arsenopyrite and orpiment initially accounted for 88% of the total As, which decreased to 48% upon the addition of SMR - this being associated with an increase in As V -ferrihydrite from 12% to 52%. In LM tailings, the pattern of As distribution and speciation was similar, with As as As V -ferrihydrite increasing from 57% to 75% upon the addition of SMR. These findings indicate that changes in ore processing technology, such as the recovery of magnetite could have significant environmental consequences regarding the As mobilisation and transformation in mine tailings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings

PubMed Central

Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A. H.

2015-01-01

Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal. PMID

Tail regeneration in Urodela: old model and new perspectives in studies

NASA Astrophysics Data System (ADS)

Grigoryan, E.; Anton, H.; Mitashov, V.

For better understanding of micro-"g" effect on nervous tissue regeneration we have chosen the regeneration of the Urodele tail, because it utilizes many developmental processes and represents the most convenient model for experiments in Space. The special interesting aspect lies in the ability of regenerates to differentiate the spinal cord (SC) and this, in turn, has a potential of practical application. Meanwhile there are conclusive evidences suggesting the production by SC cells the neurotrophic factors promoting cell proliferation and differentiation in growing tail regenerate. Previously our studies on tail regeneration in the adult newt showed that the force of gravity clearly inf luences the events underlying the regeneration. We reported the significant increase of tail regeneration rate and tissue volume of tail regenerates in the newts exposed to real and simulated low "g". In Bion 11 mission animals that were exposed 14 days in microgravity and whose tails were operated two and four weeks before launch demonstrated the regenerates achieved 1.5 - 2 times the volume of those in 1"g" control. Results of this experiment indicated also that the regeneration of central and peripheral neurons and nerve fibers was carrying out faster under low "g" conditions than in 1 "g" control. Similar data were obtained in several experiments remodeling physiological weightlessness by mean of the clinostat. It led us to the hypothesis that the stimulation of tail regeneration is linked with an over activation of neurotrophic factors produced by quickly growing SC neurons. Now we've completed the experiment on tail regeneration in the newts Tr. alpestris subjected to 5 day long clinorotation after 6 days post tail amputation. The rate of primary- and secondary regeneration was evaluated at different time points after treatment. Cell proliferation, differentiation and expression of neurotrophic proteins in SC and other major tissue-type of regenerate were investigated by

Effects of coal spoil amendment on heavy metal accumulation and physiological aspects of ryegrass (Lolium perenne L.) growing in copper mine tailings.

PubMed

Chu, Zhaoxia; Wang, Xingming; Wang, Yunmin; Liu, Guijian; Dong, Zhongbing; Lu, Xianwen; Chen, Guangzhou; Zha, Fugeng

2017-12-21

Copper mine tailings pose many threats to the surrounding environment and human health, and thus, their remediation is fundamental. Coal spoil is the waste by-product of coal mining and characterized by low levels of metals, high content of organic matter, and many essential microelements. This study was designed to evaluate the role of coal spoil on heavy uptake and physiological responses of Lolium perenne L. grown in copper mine tailings amended with coal spoil at rates of 0, 0.5, 1, 5, 10, and 20%. The results showed that applying coal spoil to copper mine tailings decreased the diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Cu, Pb, and Zn contents in tailings and reduced those metal contents in both roots and shoots of the plant. However, application of coal spoil increased the DTPA-extractable Cr concentration in tailings and also increased Cr uptake and accumulation by Lolium perenne L. The statistical analysis of physiological parameters indicated that chlorophyll and carotenoid increased at the lower amendments of coal spoil followed by a decrease compared to their respective controls. Protein content was enhanced at all the coal spoil amendments. When treated with coal spoil, the activities of superoxide dismutases (SOD), peroxidase (POD), and catalase (CAT) responded differently. CAT activity was inhibited, but POD activity was increased with increasing amendment ratio of coal spoil. SOD activity increased up to 1% coal spoil followed by a decrease. Overall, the addition of coal spoil decreased the oxidative stress in Lolium perenne L., reflected by the reduction in malondialdehyde (MDA) contents in the plant. It is concluded that coal spoil has the potential to stabilize most metals studied in copper mine tailings and ameliorate the harmful effects in Lolium perenne L. through changing the physiological attributes of the plant grown in copper mine tailings.

The Role of Histone Tails in the Nucleosome: A Computational Study

PubMed Central

Erler, Jochen; Zhang, Ruihan; Petridis, Loukas; Cheng, Xiaolin; Smith, Jeremy C.; Langowski, Jörg

2014-01-01

Histone tails play an important role in gene transcription and expression. We present here a systematic computational study of the role of histone tails in the nucleosome, using replica exchange molecular dynamics simulations with an implicit solvent model and different well-established force fields. We performed simulations for all four histone tails, H4, H3, H2A, and H2B, isolated and with inclusion of the nucleosome. The results confirm predictions of previous theoretical studies for the secondary structure of the isolated tails but show a strong dependence on the force field used. In the presence of the entire nucleosome for all force fields, the secondary structure of the histone tails is destabilized. Specific contacts are found between charged lysine and arginine residues and DNA phosphate groups and other binding sites in the minor and major DNA grooves. Using cluster analysis, we found a single dominant configuration of binding to DNA for the H4 and H2A histone tails, whereas H3 and H2B show multiple binding configurations with an equal probability. The leading stabilizing contribution for those binding configurations is the attractive interaction between the positively charged lysine and arginine residues and the negatively charged phosphate groups, and thus the resulting charge neutralization. Finally, we present results of molecular dynamics simulations in explicit solvent to confirm our conclusions. Results from both implicit and explicit solvent models show that large portions of the histone tails are not bound to DNA, supporting the complex role of these tails in gene transcription and expression and making them possible candidates for binding sites of transcription factors, enzymes, and other proteins. PMID:25517156

Crystal Structure of Bacteriophage SPP1 Distal Tail Protein (gp19.1)

PubMed Central

Veesler, David; Robin, Gautier; Lichière, Julie; Auzat, Isabelle; Tavares, Paulo; Bron, Patrick; Campanacci, Valérie; Cambillau, Christian

2010-01-01

Siphophage SPP1 infects the Gram-positive bacterium Bacillus subtilis using its long non-contractile tail and tail-tip. Electron microscopy (EM) previously allowed a low resolution assignment of most orf products belonging to these regions. We report here the structure of the SPP1 distal tail protein (Dit, gp19.1). The combination of x-ray crystallography, EM, and light scattering established that Dit is a back-to-back dimer of hexamers. However, Dit fitting in the virion EM maps was only possible with a hexamer located between the tail-tube and the tail-tip. Structure comparison revealed high similarity between Dit and a central component of lactophage baseplates. Sequence similarity search expanded its relatedness to several phage proteins, suggesting that Dit is a docking platform for the tail adsorption apparatus in Siphoviridae infecting Gram-positive bacteria and that its architecture is a paradigm for these hub proteins. Dit structural similarity extends also to non-contractile and contractile phage tail proteins (gpVN and XkdM) as well as to components of the bacterial type 6 secretion system, supporting an evolutionary connection between all these devices. PMID:20843802

Environmental Risk Assessment System for Phosphogypsum Tailing Dams

PubMed Central

Sun, Xin; Tang, Xiaolong; Yi, Honghong; Li, Kai; Zhou, Lianbi; Xu, Xianmang

2013-01-01

This paper may be of particular interest to the readers as it provides a new environmental risk assessment system for phosphogypsum tailing dams. In this paper, we studied the phosphogypsum tailing dams which include characteristics of the pollution source, environmental risk characteristics and evaluation requirements to identify the applicable environmental risk assessment methods. Two analytical methods, that is, the analytic hierarchy process (AHP) and fuzzy logic, were used to handle the complexity of the environmental and nonquantitative data. Using our assessment method, different risk factors can be ranked according to their contributions to the environmental risk, thereby allowing the calculation of their relative priorities during decision making. Thus, environmental decision-makers can use this approach to develop alternative management strategies for proposed, ongoing, and completed PG tailing dams. PMID:24382947

Environmental risk assessment system for phosphogypsum tailing dams.

PubMed

Sun, Xin; Ning, Ping; Tang, Xiaolong; Yi, Honghong; Li, Kai; Zhou, Lianbi; Xu, Xianmang

2013-01-01

This paper may be of particular interest to the readers as it provides a new environmental risk assessment system for phosphogypsum tailing dams. In this paper, we studied the phosphogypsum tailing dams which include characteristics of the pollution source, environmental risk characteristics and evaluation requirements to identify the applicable environmental risk assessment methods. Two analytical methods, that is, the analytic hierarchy process (AHP) and fuzzy logic, were used to handle the complexity of the environmental and nonquantitative data. Using our assessment method, different risk factors can be ranked according to their contributions to the environmental risk, thereby allowing the calculation of their relative priorities during decision making. Thus, environmental decision-makers can use this approach to develop alternative management strategies for proposed, ongoing, and completed PG tailing dams.

Power-law tails in the distribution of order imbalance

NASA Astrophysics Data System (ADS)

Zhang, Ting; Gu, Gao-Feng; Xu, Hai-Chuan; Xiong, Xiong; Chen, Wei; Zhou, Wei-Xing

2017-10-01

We investigate the probability distribution of order imbalance calculated from the order flow data of 43 Chinese stocks traded on the Shenzhen Stock Exchange. Two definitions of order imbalance are considered based on the order number and the order size. We find that the order imbalance distributions of individual stocks have power-law tails. However, the tail index fluctuates remarkably from stock to stock. We also investigate the distributions of aggregated order imbalance of all stocks at different timescales Δt. We find no clear trend in the tail index with respect Δt. All the analyses suggest that the distributions of order imbalance are asymmetric.

Effects of aerodynamic interaction between main and tail rotors on helicopter hover performance and noise

NASA Technical Reports Server (NTRS)

Menger, R. P.; Wood, T. L.; Brieger, J. T.

1983-01-01

A model test was conducted to determine the effects of aerodynamic interaction between main rotor, tail rotor, and vertical fin on helicopter performance and noise in hover out of ground effect. The experimental data were obtained from hover tests performed with a .151 scale Model 222 main rotor, tail rotor and vertical fin. Of primary interest was the effect of location of the tail rotor with respect to the main rotor. Penalties on main rotor power due to interaction with the tail rotor ranged up to 3% depending upon tail rotor location and orientation. Penalties on tail rotor power due to fin blockage alone ranged up to 10% for pusher tail rotors and up to 50% for tractor tail rotors. The main rotor wake had only a second order effect on these tail rotor/fin interactions. Design charts are presented showing the penalties on main rotor power as a function of the relative location of the tail rotor.

Biological enhancement of hydrocarbon extraction

DOEpatents

Brigmon, Robin L [North Augusta, SC; Berry, Christopher J [Aiken, SC

2009-01-06

A method of microbial enhanced oil recovery for recovering oil from an oil-bearing rock formation is provided. The methodology uses a consortium of bacteria including a mixture of surfactant producing bacteria and non-surfactant enzyme producing bacteria which may release hydrocarbons from bitumen containing sands. The described bioprocess can work with existing petroleum recovery protocols. The consortium microorganisms are also useful for treatment of above oil sands, ground waste tailings, subsurface oil recovery, and similar materials to enhance remediation and/or recovery of additional hydrocarbons from the materials.

A Nonluminescent and Highly Virulent Vibrio harveyi Strain Is Associated with “Bacterial White Tail Disease” of Litopenaeus vannamei Shrimp

PubMed Central

Zhou, Junfang; Fang, Wenhong; Yang, Xianle; Zhou, Shuai; Hu, Linlin; Li, Xincang; Qi, Xinyong; Su, Hang; Xie, Layue

2012-01-01

Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by “white tail” and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905) was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN), white tail disease (WTD) or penaeid white tail disease (PWTD). To differentiate from such diseases as with a sign of “white tail” but of non-bacterial origin, the present disease was named as “bacterial white tail disease (BWTD)”. Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system. PMID:22383954

Goal-directed tail use in Colombian spider monkeys (Ateles fusciceps rufiventris) is highly lateralized.

PubMed

Nelson, Eliza L; Kendall, Giulianna A

2018-02-01

Behavioral laterality refers to a bias in the use of one side of the body over the other and is commonly studied in paired organs (e.g., hands, feet, eyes, antennae). Less common are reports of laterality in unpaired organs (e.g., trunk, tongue, tail). The goal of the current study was to examine tail use biases across different tasks in the Colombian spider monkey ( Ateles fusciceps rufiventris ) for the first time (N = 14). We hypothesized that task context and task complexity influence tail laterality in spider monkeys, and we predicted that monkeys would exhibit strong preferences for using the tail for manipulation to solve out-of-reach feeding problems, but not for using the tail at rest. Our results show that a subset of spider monkeys solved each of the experimental problems through goal-directed tail use (N = 7). However, some tasks were more difficult than others, given the number of monkeys who solved the tasks. Our results supported our predictions regarding laterality in tail use and only partially replicated prior work on tail use preferences in Geoffroy's spider monkeys ( Ateles geoffroyi ). Overall, skilled tail use, but not resting tail use, was highly lateralized in Colombian spider monkeys. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Modified binders on the basis of flotation tailings

NASA Astrophysics Data System (ADS)

Shapovalov, N. A.; Zagorodnyuk, L. Kh; Shchekina, A. Yu; Gorodov, A. I.

2018-03-01

The article proposes compositions of efficient modified composite binders on the basis of portland cement and flotation tailings; the new binders attain the ultimate compressive stress that is twice as high as that of the cement stone. At that, use of annually growing volume of flotation tailings in the production of the composite binder is a rational way for recycling this type of waste and allows saving the planet's natural resources.

Testing tail-mounted transmitters with Myocastor coypus (nutria)

USGS Publications Warehouse

Merino, S.; Carter, J.; Thibodeaux, G.

2007-01-01

We developed a tail-mounted radio-transmitter for Myocastor coypus (nutria) that offers a practical and efficient alternative to collar or implant methods. The mean retention time was 96 d (range 57-147 d, n = 7), making this a practical method for short-term studies. The tail-mounts were less injurious to animals than collars and easier for field researchers to implement than either collars or surgically implanted transmitters.

14. Credit PED. Downstream elevation, near completion, showing tail race ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Credit PED. Downstream elevation, near completion, showing tail race and trestle used to carry excavated rock and construction materials across tail race. Photo c. 1909. - Dam No. 4 Hydroelectric Plant, Potomac River, Martinsburg, Berkeley County, WV

Phytostabilization of Mine Tailings in Arid and Semiarid Environments—An Emerging Remediation Technology

PubMed Central

Mendez, Monica O.; Maier, Raina M.

2008-01-01

Objective Unreclaimed mine tailings sites are a worldwide problem, with thousands of unvegetated, exposed tailings piles presenting a source of contamination for nearby communities. Tailings disposal sites in arid and semiarid environments are especially subject to eolian dispersion and water erosion. Phytostabilization, the use of plants for in situ stabilization of tailings and metal contaminants, is a feasible alternative to costly remediation practices. In this review we emphasize considerations for phytostabilization of mine tailings in arid and semiarid environments, as well as issues impeding its long-term success. Data sources We reviewed literature addressing mine closures and revegetation of mine tailings, along with publications evaluating plant ecology, microbial ecology, and soil properties of mine tailings. Data extraction Data were extracted from peer-reviewed articles and books identified in Web of Science and Agricola databases, and publications available through the U.S. Department of Agriculture, U.S. Environmental Protection Agency, and the United Nations Environment Programme. Data synthesis Harsh climatic conditions in arid and semiarid environments along with the innate properties of mine tailings require specific considerations. Plants suitable for phytostabilization must be native, be drought-, salt-, and metal-tolerant, and should limit shoot metal accumulation. Factors for evaluating metal accumulation and toxicity issues are presented. Also reviewed are aspects of implementing phytostabilization, including plant growth stage, amendments, irrigation, and evaluation. Conclusions Phytostabilization of mine tailings is a promising remedial technology but requires further research to identify factors affecting its long-term success by expanding knowledge of suitable plant species and mine tailings chemistry in ongoing field trials. PMID:18335091

Phytostabilization of mine tailings in arid and semiarid environments--an emerging remediation technology.

PubMed

Mendez, Monica O; Maier, Raina M

2008-03-01

Unreclaimed mine tailings sites are a worldwide problem, with thousands of unvegetated, exposed tailings piles presenting a source of contamination for nearby communities. Tailings disposal sites in arid and semiarid environments are especially subject to eolian dispersion and water erosion. Phytostabilization, the use of plants for in situ stabilization of tailings and metal contaminants, is a feasible alternative to costly remediation practices. In this review we emphasize considerations for phytostabilization of mine tailings in arid and semiarid environments, as well as issues impeding its long-term success. We reviewed literature addressing mine closures and revegetation of mine tailings, along with publications evaluating plant ecology, microbial ecology, and soil properties of mine tailings. Data were extracted from peer-reviewed articles and books identified in Web of Science and Agricola databases, and publications available through the U.S. Department of Agriculture, U.S. Environmental Protection Agency, and the United Nations Environment Programme. Harsh climatic conditions in arid and semiarid environments along with the innate properties of mine tailings require specific considerations. Plants suitable for phytostabilization must be native, be drought-, salt-, and metal-tolerant, and should limit shoot metal accumulation. Factors for evaluating metal accumulation and toxicity issues are presented. Also reviewed are aspects of implementing phytostabilization, including plant growth stage, amendments, irrigation, and evaluation. Phytostabilization of mine tailings is a promising remedial technology but requires further research to identify factors affecting its long-term success by expanding knowledge of suitable plant species and mine tailings chemistry in ongoing field trials.

Investigating the Microbial Degradation Potential in Oil Sands Fluid Fine Tailings Using Gamma Irradiation: A Metagenomic Perspective.

PubMed

VanMensel, Danielle; Chaganti, Subba Rao; Boudens, Ryan; Reid, Thomas; Ciborowski, Jan; Weisener, Christopher

2017-08-01

Open-pit mining of the Athabasca oil sands has generated large volumes of waste termed fluid fine tailings (FFT), stored in tailings ponds. Accumulation of toxic organic substances in the tailings ponds is one of the biggest concerns. Gamma irradiation (GI) treatment could accelerate the biodegradation of toxic organic substances. Hence, this research investigates the response of the microbial consortia in GI-treated FFT materials with an emphasis on changes in diversity and organism-related stimuli. FFT materials from aged and fresh ponds were used in the study under aerobic and anaerobic conditions. Variations in the microbial diversity in GI-treated FFT materials were monitored for 52 weeks and significant stimuli (p < 0.05) were observed. Chemoorganotrophic organisms dominated in fresh and aged ponds and showed increased relative abundance resulting from GI treatment. GI-treated anaerobic FFT aged reported stimulus of organisms with biodegradation potential (e.g., Pseudomonas, Enterobacter) and methylotrophic capabilities (e.g., Syntrophus, Smithella). In comparison, GI-treated anaerobic FFT fresh stimulated Desulfuromonas as the principle genus at 52 weeks. Under aerobic conditions, GI-treated FFT aged showed stimulation of organisms capable of sulfur and iron cycling (e.g., Geobacter). However, GI-treated aerobic FFT fresh showed no stimulus at 52 weeks. This research provides an enhanced understanding of oil sands tailings biogeochemistry and the impacts of GI treatment on microorganisms as an effect for targeting toxic organics. The outcomes of this study highlight the potential for this approach to accelerate stabilization and reclamation end points. Graphical Abstract.

Swallow-tailed kite nesting in Texas: Past and present

Treesearch

Raymond E. Brown; J. Howard Williamson; Dan B. Boone

1997-01-01

The historical breeding range of the swallow-tailed kite (Elanoides forficatus) in the United States extended from the Carolinas and Tennessee south through Florida, and Wisconsin and Minnesota south through louisiana, and Nebraska to central and southeastern Texas (Cely, 1979; Johnsgard,. 1990). By 1900, the range of the swallow-tailed kite was...

Tail Docking and Ear Cropping Dogs: Public Awareness and Perceptions

PubMed Central

Mills, Katelyn E.; Robbins, Jesse; von Keyserlingk, Marina A. G.

2016-01-01

Tail docking and ear cropping are two surgical procedures commonly performed on many dog breeds. These procedures are classified as medically unnecessary surgeries whose purpose is primarily cosmetic. Available attitude research surrounding these controversial practices has been limited to surveys of veterinarians and dog breeders familiar with both practices. The aim of this project was to: 1) assess public awareness of tail docking and ear cropping, 2) determine whether physical alteration of a dog affects how the dog, and 3) owner are perceived. In Experiment 1 awareness was measured using a combination of both explicit and implicit measures. We found that 42% of participants (n = 810) were unable to correctly explain the reason why tail docked and ear cropped dogs had short ears and tails. Similarly, an implicit measure of awareness (‘nature vs nurture task’), found that the majority of participants believed short tails and erect ears were a consequence of genetics rather than something the owner or breeder had done. The results obtained in Experiment 2 (n = 392) provide evidence that ear cropped and tail docked dogs are perceived differently than an identical dog in its ‘natural’ state. Modified dogs were perceived as being more aggressive, more dominant, less playful and less attractive than natural dogs. Experiment 3 (n = 410) is the first evidence that owners of modified dogs are perceived as being more aggressive, more narcissistic, less playful, less talkative and less warm compared to owners of natural dogs. Taken together, these results suggest that although a significant proportion of subjects appear unaware of the practices of tail docking and ear cropping in dogs, these procedures have significant impacts on how modified dogs and their owners are perceived by others. PMID:27348817

Is rhizosphere remediation sufficient for sustainable revegetation of mine tailings?

PubMed

Huang, Longbin; Baumgartl, Thomas; Mulligan, David

2012-07-01

Revegetation of mine tailings (fine-grained waste material) starts with the reconstruction of root zones, consisting of a rhizosphere horizon (mostly topsoil and/or amended tailings) and the support horizon beneath (i.e. equivalent to subsoil - mostly tailings), which must be physically and hydro-geochemically stable. This review aims to discuss key processes involved in the development of functional root zones within the context of direct revegetation of tailings and introduces a conceptual process of rehabilitating structure and function in the root zones based on a state transition model. Field studies on the revegetation of tailings (from processing base metal ore and bauxite residues) are reviewed. Particular focus is given to tailings' properties that limit remediation effectiveness. Aspects of root zone reconstruction and vegetation responses are also discussed. When reconstructing a root zone system, it is critical to restore physical structure and hydraulic functions across the whole root zone system. Only effective and holistically restored systems can control hydro-geochemical mobility of acutely and chronically toxic factors from the underlying horizon and maintain hydro-geochemical stability in the rhizosphere. Thereafter, soil biological capacity and ecological linkages (i.e. carbon and nutrient cycling) may be rehabilitated to integrate the root zones with revegetated plant communities into sustainable plant ecosystems. A conceptual framework of system transitions between the critical states of root zone development has been proposed. This will illustrate the rehabilitation process in root zone reconstruction and development for direct revegetation with sustainable plant communities. Sustainable phytostabilization of tailings requires the systematic consideration of hydro-geochemical interactions between the rhizosphere and the underlying supporting horizon. It further requires effective remediation strategies to develop hydro-geochemically stable

Tail Docking and Ear Cropping Dogs: Public Awareness and Perceptions.

PubMed

Mills, Katelyn E; Robbins, Jesse; von Keyserlingk, Marina A G

2016-01-01

Tail docking and ear cropping are two surgical procedures commonly performed on many dog breeds. These procedures are classified as medically unnecessary surgeries whose purpose is primarily cosmetic. Available attitude research surrounding these controversial practices has been limited to surveys of veterinarians and dog breeders familiar with both practices. The aim of this project was to: 1) assess public awareness of tail docking and ear cropping, 2) determine whether physical alteration of a dog affects how the dog, and 3) owner are perceived. In Experiment 1 awareness was measured using a combination of both explicit and implicit measures. We found that 42% of participants (n = 810) were unable to correctly explain the reason why tail docked and ear cropped dogs had short ears and tails. Similarly, an implicit measure of awareness ('nature vs nurture task'), found that the majority of participants believed short tails and erect ears were a consequence of genetics rather than something the owner or breeder had done. The results obtained in Experiment 2 (n = 392) provide evidence that ear cropped and tail docked dogs are perceived differently than an identical dog in its 'natural' state. Modified dogs were perceived as being more aggressive, more dominant, less playful and less attractive than natural dogs. Experiment 3 (n = 410) is the first evidence that owners of modified dogs are perceived as being more aggressive, more narcissistic, less playful, less talkative and less warm compared to owners of natural dogs. Taken together, these results suggest that although a significant proportion of subjects appear unaware of the practices of tail docking and ear cropping in dogs, these procedures have significant impacts on how modified dogs and their owners are perceived by others.

Is rhizosphere remediation sufficient for sustainable revegetation of mine tailings?

PubMed Central

Huang, Longbin; Baumgartl, Thomas; Mulligan, David

2012-01-01

Background Revegetation of mine tailings (fine-grained waste material) starts with the reconstruction of root zones, consisting of a rhizosphere horizon (mostly topsoil and/or amended tailings) and the support horizon beneath (i.e. equivalent to subsoil – mostly tailings), which must be physically and hydro-geochemically stable. This review aims to discuss key processes involved in the development of functional root zones within the context of direct revegetation of tailings and introduces a conceptual process of rehabilitating structure and function in the root zones based on a state transition model. Scope Field studies on the revegetation of tailings (from processing base metal ore and bauxite residues) are reviewed. Particular focus is given to tailings' properties that limit remediation effectiveness. Aspects of root zone reconstruction and vegetation responses are also discussed. Conclusions When reconstructing a root zone system, it is critical to restore physical structure and hydraulic functions across the whole root zone system. Only effective and holistically restored systems can control hydro-geochemical mobility of acutely and chronically toxic factors from the underlying horizon and maintain hydro-geochemical stability in the rhizosphere. Thereafter, soil biological capacity and ecological linkages (i.e. carbon and nutrient cycling) may be rehabilitated to integrate the root zones with revegetated plant communities into sustainable plant ecosystems. A conceptual framework of system transitions between the critical states of root zone development has been proposed. This will illustrate the rehabilitation process in root zone reconstruction and development for direct revegetation with sustainable plant communities. Sustainable phytostabilization of tailings requires the systematic consideration of hydro-geochemical interactions between the rhizosphere and the underlying supporting horizon. It further requires effective remediation strategies to

Effect of Dynamic Rolling Oscillations on Twin Tail Buffet Response

NASA Technical Reports Server (NTRS)

Sheta, Essam F.; Kandil, Osama A.

1999-01-01

The effect of dynamic rolling oscillations of delta-wing/twin-tail configuration on twin-tail buffet response is investigated. The computational model consists of a sharp-edged delta wing of aspect ratio one and swept-back flexible twin tail with taper ratio of 0.23. The configuration model is statically pitched at 30 deg. angle of attack and then forced to oscillate in roll around the symmetry axis at a constant amplitude of 4 deg. and reduced frequency of pi and 2(pi). The freestream Mach number and Reynolds number are 0.3 and 1.25 million, respectively. This multidisciplinary problem is solved using three sets of equations on a dynamic multi-block grid structure. The first set is the unsteady, full Navier-Stokes equations, the second set is the aeroelastic equations for coupled bending and torsion vibrations of the tails, and the third set is the grid-displacement equations. The configuration is investigated for inboard position of the twin tails which corresponds to a separation distance between the twin tails of 33% wing span. The computed results are compared with the results of stationary configuration, which previously have been validated using experimental data. The results conclusively showed that the rolling oscillations of the configuration have led to higher loads, higher deflections, and higher excitation peaks than those of the stationary configuration. Moreover, increasing the reduced frequency has led to higher loads and excitation peaks and lower bending and torsion deflections and acceleration.

On the statistical properties and tail risk of violent conflicts

NASA Astrophysics Data System (ADS)

Cirillo, Pasquale; Taleb, Nassim Nicholas

2016-06-01

We examine statistical pictures of violent conflicts over the last 2000 years, providing techniques for dealing with the unreliability of historical data. We make use of a novel approach to deal with fat-tailed random variables with a remote but nonetheless finite upper bound, by defining a corresponding unbounded dual distribution (given that potential war casualties are bounded by the world population). This approach can also be applied to other fields of science where power laws play a role in modeling, like geology, hydrology, statistical physics and finance. We apply methods from extreme value theory on the dual distribution and derive its tail properties. The dual method allows us to calculate the real tail mean of war casualties, which proves to be considerably larger than the corresponding sample mean for large thresholds, meaning severe underestimation of the tail risks of conflicts from naive observation. We analyze the robustness of our results to errors in historical reports. We study inter-arrival times between tail events and find that no particular trend can be asserted. All the statistical pictures obtained are at variance with the prevailing claims about ;long peace;, namely that violence has been declining over time.

OVERVIEW OF CYANIDE PLANT REMAINS, TAILINGS PILES, PARKING LOT, AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF CYANIDE PLANT REMAINS, TAILINGS PILES, PARKING LOT, AND MINE MANAGER'S HOME, LOOKING SOUTH SOUTHEAST. RIGHT, TAILINGS PILES ARE AT CENTER WITH CYANIDE PLANT FOUNDATIONS TO THE LEFT OF THE PILES. PARKING LOT IS AT UPPER LEFT. THE AREA BETWEEN THE COLLAPSED TANK AT CENTER LEFT AND THE REMAINS OF THE MANAGER'S HOUSE AT LOWER RIGHT IS A TAILINGS HOLDING AREA. TAILINGS FROM THE MILL WERE HELD HERE. THE LARGE SETTLING TANKS WERE CHARGED FROM THIS HOLDING AREA BY A TRAM ON RAILS AND BY A SLUICEWAY SEEN AS THE DARK SPOT ON THE CENTER LEFT EDGE OF THE FRAME. AFTER THE TAILINGS WERE LEACHED, THEY WERE DEPOSITED ON THE LARGE WASTE PILE AT CENTER RIGHT. THE TANK AT CENTER RIGHT EDGE IS WHERE THE WATER PIPELINE ENTERED THE WORKS. A STRAIGHT LINE OF POSTS IN THE GROUND GO ACROSS THE CENTER FROM LEFT TO RIGHT, WHICH ORIGINALLY SUSPENDED THE WATER PIPELINE GOING FROM THE WATER HOLDING TANK AT RIGHT UP TO THE SECONDARY WATER TANKS ABOVE THE MILL. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

Removal of heavy metals from Missouri lead mill tailings by froth flotation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benn, F.W.; Cornell, W.L.

Froth flotation techniques to remove heavy metals (Pb, Cu, and Zn) from southeast Missouri lead mill tailings were investigated. It has been estimated that southeast Missouri contains between 200 and 300 million st of Pb tailings stored above ground. The tailings were classified as two distinct types: (1) pre-1968 tailings from the Old Lead Belt (some more than 100 years old) and (2) post-1968 tailings from the New Lead Belt. The objectives of the investigation were to reduce the Pb remaining in the tailings to < 500 ppm (< 0.05 pct Pb) and to attempt to recover a marketable concentratemore » to offset a portion of the remediation costs. The remaining dolomite-limestone would then be used as mining backfill or agricultural limestone. Bench-scale froth flotation removed, in percent, 95 Pb, 84 Cu, and 54 Zn, leaving 94 pct of the original weight containing, in parts per million, 400 Pb, 40 Cu, and 300 Zn from the Old Lead Belt tailings. Separate flotation tests also removed, in percent, 85 Pb, 84 Cu, and 80 Zn, leaving 75 pct of the original weight containing, in parts per million, 400 Pb, 200 Cu, and 500 Zn from the New Lead Belt tailings. Concentrates recovered from the Old Lead Belt were retreated to produce a final Pb concentrate containing 72 pct Pb with a cleaner flotation recovery of 79 pct. Froth flotation proved to be a viable method to remove the heavy metals.« less

Supersonic aerodynamic characteristics of a low-aspect-ratio missile model with wing and tail controls and with tails in line and interdigitated

NASA Technical Reports Server (NTRS)

Graves, E. B.

1972-01-01

A study has been made to determine the aerodynamic characteristics of a low-aspect ratio cruciform missile model with all-movable wings and tails. The configuration was tested at Mach numbers from 1.50 to 4.63 with the wings in the vertical and horizontal planes and with the wings in a 45 deg roll plane with tails in line and interdigitated.

Windblown Dust Deposition Forecasting and Spread of Contamination around Mine Tailings.

PubMed

Stovern, Michael; Guzmán, Héctor; Rine, Kyle P; Felix, Omar; King, Matthew; Ela, Wendell P; Betterton, Eric A; Sáez, Avelino Eduardo

2016-02-01

Wind erosion, transport and deposition of windblown dust from anthropogenic sources, such as mine tailings impoundments, can have significant effects on the surrounding environment. The lack of vegetation and the vertical protrusion of the mine tailings above the neighboring terrain make the tailings susceptible to wind erosion. Modeling the erosion, transport and deposition of particulate matter from mine tailings is a challenge for many reasons, including heterogeneity of the soil surface, vegetative canopy coverage, dynamic meteorological conditions and topographic influences. In this work, a previously developed Deposition Forecasting Model (DFM) that is specifically designed to model the transport of particulate matter from mine tailings impoundments is verified using dust collection and topsoil measurements. The DFM is initialized using data from an operational Weather Research and Forecasting (WRF) model. The forecast deposition patterns are compared to dust collected by inverted-disc samplers and determined through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. The methodology and approach employed in this work can be generalized to other contaminated sites from which dust transport to the local environment can be assessed as a potential route for human exposure.

Windblown Dust Deposition Forecasting and Spread of Contamination around Mine Tailings

PubMed Central

Stovern, Michael; Guzmán, Héctor; Rine, Kyle P.; Felix, Omar; King, Matthew; Ela, Wendell P.; Betterton, Eric A.; Sáez, Avelino Eduardo

2017-01-01

Wind erosion, transport and deposition of windblown dust from anthropogenic sources, such as mine tailings impoundments, can have significant effects on the surrounding environment. The lack of vegetation and the vertical protrusion of the mine tailings above the neighboring terrain make the tailings susceptible to wind erosion. Modeling the erosion, transport and deposition of particulate matter from mine tailings is a challenge for many reasons, including heterogeneity of the soil surface, vegetative canopy coverage, dynamic meteorological conditions and topographic influences. In this work, a previously developed Deposition Forecasting Model (DFM) that is specifically designed to model the transport of particulate matter from mine tailings impoundments is verified using dust collection and topsoil measurements. The DFM is initialized using data from an operational Weather Research and Forecasting (WRF) model. The forecast deposition patterns are compared to dust collected by inverted-disc samplers and determined through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. The methodology and approach employed in this work can be generalized to other contaminated sites from which dust transport to the local environment can be assessed as a potential route for human exposure. PMID:29082035

Application of three tailing-based composites in treating comprehensive electroplating wastewater.

PubMed

Liu, Hongbo; Zhu, Mengling; Gao, Saisai

2014-01-01

Heavy metals and chemical oxygen demand (COD) are major challenging pollutants for most electroplating wastewater treatment plants. A novel composite material, prepared with a mixture of calcium and sodium compounds and tailings, was simply mixed by ratios and used to treat a comprehensive electroplating wastewater with influent COD, total copper (T-Cu), and total nickel (T-Ni) respectively as 690, 4.01, and 20.60 mg/L on average. Operational parameters, i.e. the contact time, pH, mass ratio of calcium and sodium compounds and tailings, were optimized as 30 min, 10.0, and 4:2:1. Removal rates for COD, T-Cu, and T-Ni could reach 71.8, 90.5, and 98.1%, respectively. No significant effect of initial concentrations on removal of T-Cu and T-Ni was observed for the composite material. The adsorption of Cu(II) and Ni(II) on the material fitted Langmuir and Freundlich isotherms respectively. Weight of waste sludge from the calcium/sodium-tailing system after reaction was 10% less than that from the calcium-tailing system. The tailing-based composite is cost-effective in combating comprehensive electroplating pollution, which shows a possibility of applying the tailings in treating electroplating wastewater.

Rational improvement of gp41-targeting HIV-1 fusion inhibitors: an innovatively designed Ile-Asp-Leu tail with alternative conformations.

PubMed

Zhu, Yun; Su, Shan; Qin, Lili; Wang, Qian; Shi, Lei; Ma, Zhenxuan; Tang, Jianchao; Jiang, Shibo; Lu, Lu; Ye, Sheng; Zhang, Rongguang

2016-09-26

Peptides derived from the C-terminal heptad repeat (CHR) of HIV gp41 have been developed as effective fusion inhibitors against HIV-1, but facing the challenges of enhancing potency and stability. Here, we report a rationally designed novel HIV-1 fusion inhibitor derived from CHR-derived peptide (Trp628~Gln653, named CP), but with an innovative Ile-Asp-Leu tail (IDL) that dramatically increased the inhibitory activity by up to 100 folds. We also determined the crystal structures of artificial fusion peptides N36- and N43-L6-CP-IDL. Although the overall structures of both fusion peptides share the canonical six-helix bundle (6-HB) configuration, their IDL tails adopt two different conformations: a one-turn helix with the N36, and a hook-like structure with the longer N43. Structural comparison showed that the hook-like IDL tail possesses a larger interaction interface with NHR than the helical one. Further molecular dynamics simulations of the two 6-HBs and isolated CP-IDL peptides suggested that hook-like form of IDL tail can be stabilized by its binding to NHR trimer. Therefore, CP-IDL has potential for further development as a new HIV fusion inhibitor, and this strategy could be widely used in developing artificial fusion inhibitors against HIV and other enveloped viruses.

Tail-extension following the termination codon is critical for release of the nascent chain from membrane-bound ribosomes in a reticulocyte lysate cell-free system.

PubMed

Takahara, Michiyo; Sakaue, Haruka; Onishi, Yukiko; Yamagishi, Marifu; Kida, Yuichiro; Sakaguchi, Masao

2013-01-11

Nascent chain release from membrane-bound ribosomes by the termination codon was investigated using a cell-free translation system from rabbit supplemented with rough microsomal membrane vesicles. Chain release was extremely slow when mRNA ended with only the termination codon. Tail extension after the termination codon enhanced the release of the nascent chain. Release reached plateau levels with tail extension of 10 bases. This requirement was observed with all termination codons: TAA, TGA and TAG. Rapid release was also achieved by puromycin even in the absence of the extension. Efficient translation termination cannot be achieved in the presence of only a termination codon on the mRNA. Tail extension might be required for correct positioning of the termination codon in the ribosome and/or efficient recognition by release factors. Copyright © 2012. Published by Elsevier Inc.

Engineering assessment of inactive uranium mill tailings: Maybell Site, Maybell, Colorado. Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1981-09-01

Ford, Bacon and Davis Utah Inc. has reevaluated the Maybell site in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Maybell, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 2.6 million dry tons of tailings at the Maybell sitemore » constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The two alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material (Option I), to disposal of the tailings in a nearby open pit mine and decontamination of the tailings site (Option II). Cost estimates for the two options are about $11,700,000 for stabilization in-place and about $22,700,000 for disposal within a distance of 2 mi. Three principal alternatives for the reprocessing of the Maybell tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $125 and $165/lb of U/sub 3/O/sub 8/ by heap leach and conventional plant processes, respectively. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery is not economically attractive at present.« less

Scour of chinook salmon redds on suction dredge tailings

Treesearch

Bret C. Harvey; Thomas E. Lisle

1999-01-01

Abstract - We measured scour of the redds of chinook salmon Oncorhynchus tshawytscha on dredge tailings and natural substrates in three tributaries of the Klamath River, California. We measured maximum scour with scour chains and net scour by surveying before and after high winter flows. Scour of chinook salmon redds located on dredge tailings exceeded scour of redds...

Release behavior of uranium in uranium mill tailings under environmental conditions.

PubMed

Liu, Bo; Peng, Tongjiang; Sun, Hongjuan; Yue, Huanjuan

2017-05-01

Uranium contamination is observed in sedimentary geochemical environments, but the geochemical and mineralogical processes that control uranium release from sediment are not fully appreciated. Identification of how sediments and water influence the release and migration of uranium is critical to improve the prevention of uranium contamination in soil and groundwater. To understand the process of uranium release and migration from uranium mill tailings under water chemistry conditions, uranium mill tailing samples from northwest China were investigated with batch leaching experiments. Results showed that water played an important role in uranium release from the tailing minerals. The uranium release was clearly influenced by contact time, liquid-solid ratio, particle size, and pH under water chemistry conditions. Longer contact time, higher liquid content, and extreme pH were all not conducive to the stabilization of uranium and accelerated the uranium release from the tailing mineral to the solution. The values of pH were found to significantly influence the extent and mechanisms of uranium release from minerals to water. Uranium release was monitored by a number of interactive processes, including dissolution of uranium-bearing minerals, uranium desorption from mineral surfaces, and formation of aqueous uranium complexes. Considering the impact of contact time, liquid-solid ratio, particle size, and pH on uranium release from uranium mill tailings, reducing the water content, decreasing the porosity of tailing dumps and controlling the pH of tailings were the key factors for prevention and management of environmental pollution in areas near uranium mines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of Emergent Data Networks Among Long-Tail Data

NASA Astrophysics Data System (ADS)

Elag, Mostafa; Kumar, Praveen; Hedstrom, Margaret; Myers, James; Plale, Beth; Marini, Luigi; McDonald, Robert

2014-05-01

Data curation underpins data-driven scientific advancements. It manages the information flux across multiple users throughout data life cycle as well as increases data sustainability and reusability. The exponential growth in data production spanning across the Earth Science involving individual and small research groups, which is termed as log-tail data, increases the data-knowledge latency among related domains. It has become clear that an advanced framework-agnostic metadata and ontologies for long-tail data is required to increase their visibility to each other, and provide concise and meaningful descriptions that reveal their connectivity. Despite the advancement that has been achieved by various sophisticated data management models in different Earth Science disciplines, it is not always straightforward to derive relationships among long-tail data. Semantic data clustering algorithms and pre-defined logic rules that are oriented toward prediction of possible data relationships, is one method to address these challenges. Our work advances the connectivity of related long-tail data by introducing the design for an ontology-based knowledge management system. In this work, we present the system architecture, its components, and illustrate how it can be used to scrutinize the connectivity among datasets. To demonstrate the capabilities of this "data network" prototype, we implemented this approach within the Sustainable Environment Actionable Data (SEAD) environment, an open-source semantic content repository that provides a RDF database for long-tail data, and show how emergent relationships among datasets can be identified.

The environmental impacts of one of the largest tailing dam failures worldwide.

PubMed

Hatje, Vanessa; Pedreira, Rodrigo M A; de Rezende, Carlos Eduardo; Schettini, Carlos Augusto França; de Souza, Gabriel Cotrim; Marin, Danieli Canaver; Hackspacher, Peter Christian

2017-09-06

The impacts of the SAMARCO iron tailing spill along more than 650 km, between the dam and the plume of the Doce River in the Atlantic, were assessed by the determination of toxic metals. The tailing spill caused a substantial increase in suspended sediment loads (up to 33,000 mg L -1 ), in addition to large depositions of waste along the Doce basin. The highest estimated transport of dissolved metals was observed for Fe (58.8 μg s -1 ), Ba (37.9 μg s -1 ) and Al (25.0 μg s -1 ). Sediments reached the highest enrichment factors (EFs) for Hg (4,234), Co (133), Fe (43), and Ni (16), whereas As (55), Ba (64), Cr (16), Cu (17), Mn (41), Pb (38) and Zn (82) highest EFs were observed for suspended particulate matter (SPM). Iron, As, Hg, Mn exceeded sediment quality guidelines. Therefore, the risk of occurrence of adverse effects is highly possible, not only due to the dam failure, but also due to the Fe mining and the artisan Au mining. Heavy rain episodes will likely cause enhanced erosion, remobilization, and transport of contaminated particles, sustaining high inputs of SPM and metals for the years to come and threatening the ecosystem services.

Diagnostic Simulations of the Lunar Exosphere using Coma and Tail

NASA Astrophysics Data System (ADS)

Lee, Dong Wook; Kim, Sang J.

2017-10-01

The characteristics of the lunar exosphere can be constrained by comparing simulated models with observational data of the coma and tail (Lee et al., JGR, 2011); and thus far a few independent approaches on this issue have been performed and presented in the literature. Since there are two-different observational constraints for the lunar exosphere, it is interesting to find the best exospheric model that can account for the observed characteristics of the coma and tail. Considering various initial conditions of different sources and space weather, we present preliminary time-dependent simulations between the initial and final stages of the development of the lunar tail. Based on an updated 3-D model, we are planning to conduct numerous simulations to constrain the best model parameters from the coma images obtained from coronagraph observations supported by a NASA monitoring program (Morgan, Killen, and Potter, AGU, 2015) and future tail data.

Field evaluation of the effectiveness of three industrial by-products as organic amendments for phytostabilization of a Pb/Zn mine tailings.

PubMed

Yang, Shengxiang; Cao, Jianbing; Li, Fengmei; Peng, Xizhu; Peng, Qingjing; Yang, Zhihui; Chai, Liyuan

2016-01-01

Although the potential of industrial by-products as organic amendments for phytostabilization has long been recognized, most of the previous studies addressing this issue have been laboratory-based. In this study, a field trial was conducted to evaluate the effectiveness of three industrial by-products [sweet sorghum vinasse (SSV), medicinal herb residues (MHR) and spent mushroom compost (SMC)] as organic amendments for phytostabilization of abandoned Pb/Zn mine tailings. Our results showed the following: (i) when compared to the control tailings, the mean concentrations of diethylene-triamine-pentaacetic acid (DTPA)-extractable Cd, Cu, Pb and Zn in SSV, MHR and SMC treatments decreased by 20.8-28.0%, 41.6-49.1%, 17.7-22.7% and 9.5-14.7%, respectively; (ii) the mean values of organic C, ammonium-N and available P in SSV, MHR and SMC treatments increased by 1.7-2.8, 10.8-14.9 and 3.9-5.1 times as compared with the mine tailings; and (iii) the addition of SSV, MHR and SMC significantly enhanced soil respiration and microbial biomass being 1.5-1.8 and 1.3-1.6 fold higher than those in the control tailings. There were no significant differences in soil biochemical properties among the plots amended with these by-products, suggesting that they were almost equally effective in improving the biochemical conditions of the tailings. In addition, the application of these amendments promoted seed germination, seedling growth, and consequently increased the vegetation cover and its biomass. Moreover, concentrations of Cd, Cu, Pb and Zn in above-ground parts of the plants were below the toxicity limit levels for animals. The results obtained in this field study confirmed that the three organic-rich industrial by-products could be used as amendments for phytostabilization of some types of mine tailings.

Enhanced production of L-sorbose from D-sorbitol by improving the mRNA abundance of sorbitol dehydrogenase in Gluconobacter oxydans WSH-003.

PubMed

Xu, Sha; Wang, Xiaobei; Du, Guocheng; Zhou, Jingwen; Chen, Jian

2014-10-18

Production of L-sorbose from D-sorbitol by Gluconobacter oxydans is the first step to produce L-ascorbic acid on industrial scale. The sldhAB gene, which encodes the sorbitol dehydrogenase (SLDH), was overexpressed in an industrial strain G. oxydans WSH-003 with a strong promoter, P tufB . To enhance the mRNA abundance, a series of artificial poly(A/T) tails were added to the 3'-terminal of sldhAB gene. Besides, their role in sldhAB overexpression and their subsequent effects on L-sorbose production were investigated. The mRNA abundance of the sldhAB gene could be enhanced in G. oxydans by suitable poly(A/T) tails. By self-overexpressing the sldhAB gene in G. oxydans WSH-003 with an optimal poly(A/T) tail under the constitutive promoter P tufB , the titer and the productivity of L-sorbose were enhanced by 36.3% and 25.0%, respectively, in a 1-L fermenter. Immobilization of G. oxydans-sldhAB6 cells further improved the L-sorbose titer by 33.7% after 20 days of semi-continuous fed-batch fermentation. The artificial poly(A/T) tails could significantly enhance the mRNA abundance of the sldhAB. Immobilized G. oxydans-sldhAB6 cells could further enlarge the positive effect caused by enhanced mRNA abundance of the sldhAB.

White-tailed deer in the Midwest.

Treesearch

USDA FS

1970-01-01

Discusses the present status and future prospects of the nonyarding white-tailed deer population in the Midwestern United States. Range appraisal, habitat, harvest regulation, and population control are included.

Speciation and characterization of arsenic in Ketza River mine tailings using X-ray absorption spectroscopy.

PubMed

Paktunc, Dogan; Foster, Andrea; Laflamme, Gilles

2003-05-15

Ketza River mine tailings deposited underwater and those exposed near the tailings impoundment contain approximately 4 wt % As. Column-leaching tests indicated the potential for high As releases from the tailings. The tailings are composed dominantly of iron oxyhydroxides, quartz, calcite, dolomite, muscovite, ferric arsenates, and calcium-iron arsenates. Arsenopyrite and pyrite are trace constituents. Chemical compositions of iron oxyhydroxide and arsenate minerals are highly variable. The XANES spectra indicate that arsenic occurs as As(V) in tailings, but air-drying prior to analysis may have oxidized lower-valent As. The EXAFS spectra indicate As-Fe distances of 3.35-3.36 A for the exposed tailings and 3.33-3.35 A for the saturated tailings with coordination numbers of 0.96-1.11 and 0.46-0.64, respectively. The As-Ca interatomic distances ranging from 4.15 to 4.18 A and the coordination numbers of 4.12-4.58 confirm the presence of calcium-iron arsenates in the tailings. These results suggest that ferric arsenates and inner-sphere corner sharing or bidentate-binuclear attachment of arsenate tetrahedra onto iron hydroxide octahedra are the dominant form of As in the tailings. EXAFS spectra indicate that the exposed tailings are richer in arsenate minerals whereas the saturated tailings are dominated by the iron oxyhydroxides, which could help explain the greater release of As from the exposed tailings during leaching tests. It is postulated that the dissolution of ferric arsenates during flow-through experiments caused the high As releases from both types of tailings. Arsenic tied to iron oxyhydroxides as adsorbed species are considered stable; however, iron oxyhydroxides having low Fe/As molar ratios may not be as stable. Continued As releases from the tailings are likely due to dissolution of both ferric and calcium-iron arsenates and desorption of As from high-As bearing iron oxyhydroxides during aging.

Speciation and characterization of arsenic in Ketza River mine tailings using x-ray absorption spectroscopy

USGS Publications Warehouse

Paktunc, D.; Foster, A.; Laflamme, G.

2003-01-01

Ketza River mine tailings deposited underwater and those exposed near the tailings impoundment contain approximately 4 wt % As. Column-leaching tests indicated the potential for high As releases from the tailings. The tailings are composed dominantly of iron oxyhydroxides, quartz, calcite, dolomite, muscovite, ferric arsenates, and calcium-iron arsenates. Arsenopyrite and pyrite are trace constituents. Chemical compositions of iron oxyhydroxide and arsenate minerals are highly variable. The XANES spectra indicate that arsenic occurs as As(V) in tailings, but air-drying prior to analysis may have oxidized lower-valent As. The EXAFS spectra indicate As-Fe distances of 3.35-3.36 A?? for the exposed tailings and 3.33-3.35 A?? for the saturated tailings with coordination numbers of 0.96-1.11 and 0.46-0.64, respectively. The As-Ca interatomic distances ranging from 4.15 to 4.18 A?? and the coordination numbers of 4.12-4.58 confirm the presence of calcium-iron arsenates in the tailings. These results suggest that ferric arsenates and inner-sphere corner sharing or bidentatebinuclear attachment of arsenate tetrahedra onto iron hydroxide octahedra are the dominant form of As in the tailings. EXAFS spectra indicate that the exposed tailings are richer in arsenate minerals whereas the saturated tailings are dominated by the iron oxyhydroxides, which could help explain the greater release of As from the exposed tailings during leaching tests. It is postulated that the dissolution of ferric arsenates during flow-through experiments caused the high As releases from both types of tailings. Arsenic tied to iron oxyhydroxides as adsorbed species are considered stable; however, iron oxyhydroxides having low Fe/As molar ratios may not be as stable. Continued As releases from the tailings are likely due to dissolution of both ferric and calcium-iron arsenates and desorption of As from high-As bearing iron oxyhydroxides during aging.

The Tail-Elicited Tail Withdrawal Reflex of "Aplysia" Is Mediated Centrally at Tail Sensory-Motor Synapses and Exhibits Sensitization across Multiple Temporal Domains

ERIC Educational Resources Information Center

Philips, Gary T.; Sherff, Carolyn M.; Menges, Steven A.; Carew, Thomas J.

2011-01-01

The defensive withdrawal reflexes of "Aplysia californica" have provided powerful behavioral systems for studying the cellular and molecular basis of memory formation. Among these reflexes the (T-TWR) has been especially useful. In vitro studies examining the monosynaptic circuit for the T-TWR, the tail sensory-motor (SN-MN) synapses, have…

Ulysses feels the brush of a comet's tail

NASA Astrophysics Data System (ADS)

2000-04-01

"Ulysses's prime task is to map the solar wind above the Sun's poles: it had not been looking for Hyakutake, which happened to be at its closest approach to the Sun on 1 May 1996, or any other comet", says Richard Marsden, ESA's Ulysses Project Scientist. "Ulysses was just in the right place at the right time." The two teams stumbled across the telltale signature of a comet quite independently when poring over old Ulysses data. Jones and colleagues found their evidence in magnetic field data: "the magnetic field lines were draped in a way that you'd expect in a comet's tail," says Jones. The other instrument team, lead by George Gloeckler from the University of Maryland, found their evidence when looking at the composition of the solar wind. Cometary tails are rich in oxygen and carbon compared with the solar wind, but depleted in nitrogen and neon. The Imperial College team identified Hyakutake as the source of the anomalous readings. On 1 May 1996, Ulysses was aligned with the Sun and the position Hyakutake had occupied eight days earlier, which Jones calculated was the time needed for material leaving the comet's nucleus to travel the distance to Ulysses. One of the most surprising aspects of the discovery is the length of Hyakutake's tail. Cometary experts had thought that comet tails eventually spread out and lose their integrity. "We found that the whole thing is preserved as an entity and doesn't spread out very much," says Gloeckler. "If it can persist as far as Ulysses, there's no reason to presume that it wouldn't continue to the edge of the heliosphere (the boundary about 100AU from the Sun between the solar wind and the interstellar medium)," says Jones. "This discovery makes us wonder whether Ulysses or other spacecraft have crossed a comet tail before. So we're going back to look again for other signatures. But it's probably a rare event," says Jones. The comet nucleus has to be in exactly the right position with respect to the Sun and the spacecraft

Application of a life cycle assessment to compare environmental performance in coal mine tailings management.

PubMed

Adiansyah, Joni Safaat; Haque, Nawshad; Rosano, Michele; Biswas, Wahidul

2017-09-01

This study compares coal mine tailings management strategies using life cycle assessment (LCA) and land-use area metrics methods. Hybrid methods (the Australian indicator set and the ReCiPe method) were used to assess the environmental impacts of tailings management strategies. Several strategies were considered: belt filter press (OPT 1), tailings paste (OPT 2), thickened tailings (OPT 3), and variations of OPT 1 using combinations of technology improvement and renewable energy sources (OPT 1A-D). Electrical energy was found to contribute more than 90% of the environmental impacts. The magnitude of land-use impacts associated with OPT 3 (thickened tailings) were 2.3 and 1.55 times higher than OPT 1 (tailings cake) and OPT 2 (tailings paste) respectively, while OPT 1B (tailings belt filter press with technology improvement and solar energy) and 1D (tailings belt press filter with technology improvement and wind energy) had the lowest ratio of environmental impact to land-use. Further analysis of an economic cost model and reuse opportunities is required to aid decision making on sustainable tailings management and industrial symbiosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

A blind climber: The first evidence of ultrasonic echolocation in arboreal mammals.

PubMed

Panyutina, Aleksandra A; Kuznetsov, Alexander N; Volodin, Ilya A; Abramov, Alexei V; Soldatova, Irina B

2017-03-01

The means of orientation is studied in the Vietnamese pygmy dormouse Typhlomys chapensis, a poorly known enigmatic semi-fossorial semi-arboreal rodent. Data on eye structure are presented, which prove that Typhlomys (translated as "the blind mouse") is incapable of object vision: the retina is folded and retains no more than 2500 ganglion cells in the focal plane, and the optic nerve is subject to gliosis. Hence, Typhlomys has no other means for rapid long-range orientation among tree branches other than echolocation. Ultrasonic vocalization recordings at the frequency range of 50-100 kHz support this hypothesis. The vocalizations are represented by bouts of up to 7 more or less evenly-spaced and uniform frequency-modulated sweep-like pulses in rapid succession. Structurally, these sweeps are similar to frequency-modulated ultrasonic echolocation calls of some bat species, but they are too faint to be revealed with a common bat detector. When recording video simultaneously with the ultrasonic audio, a significantly greater pulse rate during locomotion compared to that of resting animals has been demonstrated. Our findings of locomotion-associated ultrasonic vocalization in a fast-climbing but weakly-sighted small mammal ecotype add support to the "echolocation-first theory" of pre-flight origin of echolocation in bats. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

12. Credit PED. View of tail race and dam showing ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Credit PED. View of tail race and dam showing dumping of construction rubble into river bed by rail car; and preparations for pouring a concrete cap onto tail race wall. Photo c. 1909. - Dam No. 4 Hydroelectric Plant, Potomac River, Martinsburg, Berkeley County, WV

Microscopic understanding of heavy-tailed return distributions in an agent-based model

NASA Astrophysics Data System (ADS)

Schmitt, Thilo A.; Schäfer, Rudi; Münnix, Michael C.; Guhr, Thomas

2012-11-01

The distribution of returns in financial time series exhibits heavy tails. It has been found that gaps between the orders in the order book lead to large price shifts and thereby to these heavy tails. We set up an agent-based model to study this issue and, in particular, how the gaps in the order book emerge. The trading mechanism in our model is based on a double-auction order book. In situations where the order book is densely occupied with limit orders we do not observe fat-tailed distributions. As soon as less liquidity is available, a gap structure forms which leads to return distributions with heavy tails. We show that return distributions with heavy tails are an order-book effect if the available liquidity is constrained. This is largely independent of specific trading strategies.

Extreme values and fat tails of multifractal fluctuations

NASA Astrophysics Data System (ADS)

Muzy, J. F.; Bacry, E.; Kozhemyak, A.

2006-06-01

In this paper we discuss the problem of the estimation of extreme event occurrence probability for data drawn from some multifractal process. We also study the heavy (power-law) tail behavior of probability density function associated with such data. We show that because of strong correlations, the standard extreme value approach is not valid and classical tail exponent estimators should be interpreted cautiously. Extreme statistics associated with multifractal random processes turn out to be characterized by non-self-averaging properties. Our considerations rely upon some analogy between random multiplicative cascades and the physics of disordered systems and also on recent mathematical results about the so-called multifractal formalism. Applied to financial time series, our findings allow us to propose an unified framework that accounts for the observed multiscaling properties of return fluctuations, the volatility clustering phenomenon and the observed “inverse cubic law” of the return pdf tails.

Arsenic removal using steel manufacturing byproducts as permeable reactive materials in mine tailing containment systems.

PubMed

Ahn, Joo Sung; Chon, Chul-Min; Moon, Hi-Soo; Kim, Kyoung-Woong

2003-05-01

Steel manufacturing byproducts were tested as a means of treating mine tailing leachate with a high As concentration. Byproduct materials can be placed in situ as permeable reactive barriers to control the subsurface release of leachate from tailing containment systems. The tested materials had various compositions of elemental Fe, Fe oxides, Ca-Fe oxides and Ca hydroxides typical of different steel manufacturing processes. Among these materials, evaporation cooler dust (ECD), oxygen gas sludge (OGS), basic oxygen furnace slag (BOFS) and to a lesser degree, electrostatic precipitator dust (EPD) effectively removed both As(V) and As(III) during batch experiments. ECD, OGS and BOFS reduced As concentrations to <0.5mg/l from 25mg/l As(V) or As(III) solution in 72 h, exhibiting higher removal capacities than zero-valent iron. High Ca concentrations and alkaline conditions (pH ca. 12) provided by the dissolution of Ca hydroxides may promote the formation of stable, sparingly soluble Ca-As compounds. When initial pH conditions were adjusted to 4, As reduction was enhanced, probably by adsorption onto iron oxides. The elution rate of retained As from OGS and ECD decreased with treatment time, and increasing the residence time in a permeable barrier strategy would be beneficial for the immobilization of As. When applied to real tailing leachate, ECD was found to be the most efficient barrier material to increase pH and to remove As and dissolved metals.

Random-Walk Type Model with Fat Tails for Financial Markets

NASA Astrophysics Data System (ADS)

Matuttis, Hans-Geors

Starting from the random-walk model, practices of financial markets are included into the random-walk so that fat tail distributions like those in the high frequency data of the SP500 index are reproduced, though the individual mechanisms are modeled by normally distributed data. The incorporation of local correlation narrows the distribution for "frequent" events, whereas global correlations due to technical analysis leads to fat tails. Delay of market transactions in the trading process shifts the fat tail probabilities downwards. Such an inclusion of reactions to market fluctuations leads to mini-trends which are distributed with unit variance.

A statistical analysis of substorm associated tail activity

NASA Astrophysics Data System (ADS)

Hsu, Tung-Shin; McPherron, Robert L.

2012-11-01

Substorm onset timing is a critical issue in magnetotail dynamics research. Solar wind energy is accumulated in the magnetosphere and the configuration of the magnetosphere evolves toward an unstable state during the growth phase. At some point, the expansion phase begins and the stored energy is released through a variety of processes that return the magnetosphere to a lower energy state. In recovery the various processes die away. Unfortunately, the ground and magnetospheric signatures of onset, i.e. energy release, can be seen both in the growth phase prior to onset and in the expansion phase after onset. Some investigators refer to each of these events as a substorm. Tail observations suggest that most substorms have one event that differentiates the behavior of the tail field and plasma. We refer to this time as the "main substorm onset". Each substorm associated phenomenon is timed independently and then compared with main substorm onsets. ISEE-2 tail observations are used to examine the tail lobe magnetic conditions associated with substorms because ISEE-2 orbit has a high inclination and frequently observes lobe field. Approximately 70 ˜ 75% of tail lobe Bt and Bz change are associated with the main substorm onset. If the satellite is more than 3 Re above (below) the neutral sheet, 86% (57%) of plasma pressure dropouts are associated with substorms. We interpret our results as evidence that the effect of the growth phase is to drive the magnetosphere towards instability. As it approaches global instability local regions become temporarily unstable but are rapidly quenched. Eventually one of these events develops into the global instability that releases most of the stored energy and returns the magnetosphere to a more stable configuration.

Wake structures behind a swimming robotic lamprey with a passively flexible tail

PubMed Central

Leftwich, Megan C.; Tytell, Eric D.; Cohen, Avis H.; Smits, Alexander J.

2012-01-01

SUMMARY A robotic lamprey, based on the silver lamprey, Ichthyomyzon unicuspis, was used to investigate the influence of passive tail flexibility on the wake structure and thrust production during anguilliform swimming. A programmable microcomputer actuated 11 servomotors that produce a traveling wave along the length of the lamprey body. The waveform was based on kinematic studies of living lamprey, and the shape of the tail was taken from a computer tomography scan of the silver lamprey. The tail was constructed of flexible PVC gel, and nylon inserts were used to change its degree of flexibility. Particle image velocimetry measurements using three different levels of passive flexibility show that the large-scale structure of the wake is dominated by the formation of two pairs of vortices per shedding cycle, as seen in the case of a tail that flexed actively according to a pre-defined kinematic pattern, and did not bend in response to fluid forces. When the tail is passively flexible, however, the large structures are composed of a number of smaller vortices, and the wake loses coherence as the degree of flexibility increases. Momentum balance calculations indicate that, at a given tailbeat frequency, increasing the tail flexibility yields less net force, but changing the cycle frequency to match the resonant frequency of the tail increases the force production. PMID:22246250

Black-tailed prairie dog status and future conservation planning

Treesearch

Daniel W. Mulhern; Craig J. Knowles

1997-01-01

The black-tailed prairie dog is one of five prairie dog species estimated to have once occupied up to 100 million ha or more in North America. The area occupied by black-tailed prairie dogs has declined to approximately 2% of its former range. Conversion of habitat to other land uses and widespread prairie dog eradication efforts combined with sylvatic plague,

A 70 Kiloparsec X-Ray Tail in the Cluster A3627

NASA Technical Reports Server (NTRS)

Sun, M.; Jones, C.; Forman, W.; Nulsen, P. E. J.; Donahue, M.; Voit, G. M.

2006-01-01

We present the discovery of a 70 kpc X-ray tail behind the small late-type galaxy ESO 137-001, in the nearby, hot (T=6.5 keV) merging cluster A3627, from both Chandra and XMM-Newton observations. The tail has a length-to-width ratio of approx. 10. It is luminous (L(0.5-2keV) approx 1041 ergs/s), with a temperature of approx. 0.7 keV and an X-ray gas mass of approx 10(exp 9) solar masses (approx 10% of the galaxy's stellar mass). We interpret this tail as the stripped interstellar medium of ESO 137-001 mixed with the hot cluster medium, with this blue galaxy being converted into a gas-poor galaxy. Three X-ray point sources are detected in the axis of the tail, which may imply active star formation there. The straightness and narrowness of the tail also imply that the turbulence in the intracluster medium is not strong on scales of 20-70 kpc.

The Anatomy of the Long Tail of Consumer Demand

NASA Astrophysics Data System (ADS)

Broder, Andrei

The long tail of consumer demand is consistent with two fundamentally different theories. The first, and more popular hypothesis, is that a majority of consumers have similar tastes and only few have any interest in niche content; the second, is that everyone is a bit eccentric, consuming both popular and niche products. By examining extensive data on user preferences for movies, music, web search, and web browsing, we found overwhelming support for the latter theory. Our investigation suggests an additional factor in the success of "infinite-inventory" retailers such as Netflix and Amazon: besides the significant revenue obtained from tail sales, tail availability may boost head sales by offering consumers the convenience of "one-stop shopping" for both their mainstream and niche interests.

Measurements of atmospheric turbulence effects on tail rotor acoustics

NASA Technical Reports Server (NTRS)

Hagen, Martin J.; Yamauchi, Gloria K.; Signor, David B.; Mosher, Marianne

1994-01-01

Results from an outdoor hover test of a full-scale Lynx tail rotor are presented. The investigation was designed to further the understanding of the acoustics of an isolated tail rotor hovering out-of-ground effect in atmospheric turbulence, without the effects of the main rotor wake or other helicopter components. Measurements include simultaneous rotor performance, noise, inflow, and far-field atmospheric turbulence. Results with grid-generated inflow turbulence are also presented. The effects of atmospheric turbulence ingestion on rotor noise are quantified. In contradiction to current theories, increasing rotor inflow and rotor thrust were found to increase turbulence ingestion noise. This is the final report of Task 13A--Helicopter Tail Rotor Noise, of the NASA/United Kingdom Defense Research Agency cooperative Aeronautics Research Program.

Tail autotomy affects bipedalism but not sprint performance in a cursorial Mediterranean lizard

NASA Astrophysics Data System (ADS)

Savvides, Pantelis; Stavrou, Maria; Pafilis, Panayiotis; Sfenthourakis, Spyros

2017-02-01

Running is essential in all terrestrial animals mainly for finding food and mates and escaping from predators. Lizards employ running in all their everyday functions, among which defense stands out. Besides flight, tail autotomy is another very common antipredatory strategy within most lizard families. The impact of tail loss to sprint performance seems to be species dependent. In some lizard species, tail shedding reduces sprint speed, in other species, increases it, and, in a few species, speed is not affected at all. Here, we aimed to clarify the effect of tail autotomy on the sprint performance of a cursorial lizard with particular adaptations for running, such as bipedalism and spike-like protruding scales (fringes) on the toepads that allow high speed on sandy substrates. We hypothesized that individuals that performed bipedalism, and have more and larger fringes, would achieve higher sprint performance. We also anticipated that tail shedding would affect sprint speed (though we were not able to define in what way because of the unpredictable effects that tail loss has on different species). According to our results, individuals that ran bipedally were faster; limb length and fringe size had limited effects on sprint performance whereas tail autotomy affected quadrupedal running only in females. Nonetheless, tail loss significantly affected bipedalism: the ability for running on hindlimbs was completely lost in all adult individuals and in 72.3% of juveniles.

Tail autotomy affects bipedalism but not sprint performance in a cursorial Mediterranean lizard.

PubMed

Savvides, Pantelis; Stavrou, Maria; Pafilis, Panayiotis; Sfenthourakis, Spyros

2017-02-01

Running is essential in all terrestrial animals mainly for finding food and mates and escaping from predators. Lizards employ running in all their everyday functions, among which defense stands out. Besides flight, tail autotomy is another very common antipredatory strategy within most lizard families. The impact of tail loss to sprint performance seems to be species dependent. In some lizard species, tail shedding reduces sprint speed, in other species, increases it, and, in a few species, speed is not affected at all. Here, we aimed to clarify the effect of tail autotomy on the sprint performance of a cursorial lizard with particular adaptations for running, such as bipedalism and spike-like protruding scales (fringes) on the toepads that allow high speed on sandy substrates. We hypothesized that individuals that performed bipedalism, and have more and larger fringes, would achieve higher sprint performance. We also anticipated that tail shedding would affect sprint speed (though we were not able to define in what way because of the unpredictable effects that tail loss has on different species). According to our results, individuals that ran bipedally were faster; limb length and fringe size had limited effects on sprint performance whereas tail autotomy affected quadrupedal running only in females. Nonetheless, tail loss significantly affected bipedalism: the ability for running on hindlimbs was completely lost in all adult individuals and in 72.3% of juveniles.

Thermo-mechanical properties and microfabric of fly ash-stabilized gold tailings.

PubMed

Lee, Joon Kyu; Shang, Julie Q; Jeong, Sangseom

2014-07-15

This paper studies the changes in thermal conductivity, temperature, and unconfined compressive strength of gold tailings and fly ash mixtures during the curing period of 5 days. The microfabric of the cured mixtures was investigated with mercury intrusion porosimetry (MIP). The mixture samples were prepared at their maximum dry unit weight and optimum moisture content. Effect of adding fly ash to gold tailings (i.e., 0, 20, and 40% of the dry weight of tailings) was examined, and a comparison was made on samples prepared at the same fly ash content by replacing gold tailings with humic acid (i.e., gold tailings and humic acid ratios of 100:0, 90:10, and 80:20 by weight) or by varying pore fluid chemistry (i.e., water and salt solutions of 1M NaCl and CaCl2). The results show that the initial thermal conductivity of the samples is sensitive to the mixture proportion and a declination in the thermal conductivity is observed due to hydration of fly ash and evaporation. Inclusion of fly ash and salts into gold tailings improves the unconfined compressive strength but the presence of humic acid in samples leads to the decrease of the strength. MIP results reveal the pore structure changes associated with the packing states of the samples that reflect the influential factors considered. Copyright © 2014 Elsevier B.V. All rights reserved.

Role of the tail in the regulated state of myosin 2

PubMed Central

Jung, HyunSuk; Billington, Neil; Thirumurugan, Kavitha; Salzameda, Bridget; Cremo, Christine R.; Chalovich, Joseph M.; Chantler, Peter D.; Knight, Peter J.

2013-01-01

Myosin 2 from vertebrate smooth muscle or non-muscle sources is in equilibrium between compact, inactive monomers and thick filaments under physiological conditions. In the inactive monomer, the two heads pack compactly together and the long tail is folded into three closely-packed segments that are associated chiefly with one of the heads. The molecular basis of the folding of the tail remains unexplained. Using electron microscopy, we show that compact monomers of smooth muscle myosin 2 have the same structure in both the native state and following specific, intramolecular photo-cross-linking between Cys109 of the regulatory light chain (RLC) and segment 3 of the tail. Non-specific cross-linking between lysine residues of the folded monomer by glutaraldehyde also does not perturb the compact conformation, and stabilises it against unfolding at high ionic strength. Sequence comparisons across phyla and myosin 2 isoforms suggest that folding of the tail is stabilised by ionic interactions between the positively-charged N-terminal sequence of the RLC and a negatively-charged region near the start of tail segment 3, and that phosphorylation of the RLC could perturb these interactions. Our results support the view that interactions between the heads and the distal tail perform a critical role in regulating activity of myosin 2 molecules through stabilising the compact monomer conformation. PMID:21419133

NONINVASIVE, CONTINUOUS MEASUREMENT OF RAT TAIL SKIN TEMPERATURE BY RADIOTELEMETRY.

EPA Science Inventory

Tail skin temperature (Tsk) can provide a wealth of information on the thermoregulatory status of the rat. Drug- and toxic-induced changes in body temperature are often mediated by vasodilation or constriction of blood flow to the tail and Tsk can generally be used as an indica...

Tails and bridges in the parabolic restricted three-body problem

NASA Astrophysics Data System (ADS)

Barrabés, Esther; Cors, Josep M.; Garcia-Taberner, Laura; Ollé, Mercè

2017-12-01

After a close encounter of two galaxies, bridges and tails can be seen between or around them. A bridge would be a spiral arm between a galaxy and its companion, whereas a tail would correspond to a long and curving set of debris escaping from the galaxy. The goal of this paper is to present a mechanism, applying techniques of dynamical systems theory, that explains the formation of tails and bridges between galaxies in a simple model, the so-called parabolic restricted three-body problem, i.e. we study the motion of a particle under the gravitational influence of two primaries describing parabolic orbits. The equilibrium points and the final evolutions in this problem are recalled,and we show that the invariant manifolds of the collinear equilibrium points and the ones of the collision manifold explain the formation of bridges and tails. Massive numerical simulations are carried out and their application to recover previous results are also analysed.

Low molecular weight carboxylic acids in oxidizing porphyry copper tailings.

PubMed

Dold, Bernhard; Blowes, David W; Dickhout, Ralph; Spangenberg, Jorge E; Pfeifer, Hans-Rudolf

2005-04-15

The distribution of low molecular weight carboxylic acids (LMWCA) was investigated in pore water profiles from two porphyry copper tailings impoundments in Chile (Piuquenes at La Andina and Cauquenes at El Teniente mine). The objectives of this study were (1) to determine the distribution of LMWCA, which are interpreted to be the metabolic byproducts of the autotroph microbial community in this low organic carbon system, and (2) to infer the potential role of these acids in cycling of Fe and other elements in the tailings impoundments. The speciation and mobility of iron, and potential for the release of H+ via hydrolysis of the ferric iron, are key factors in the formation of acid mine drainage in sulfidic mine wastes. In the low-pH oxidation zone of the Piuquenes tailings, Fe(III) is the dominant iron species and shows high mobility. LMWCA, which occur mainly between the oxidation front down to 300 cm below the tailings surface at both locations (e.g., max concentrations of 0.12 mmol/L formate, 0.17 mmol/L acetate, and 0.01 mmol/L pyruvate at Piuquenes and 0.14 mmol/L formate, 0.14 mmol/L acetate, and 0.006 mmol/L pyruvate at Cauquenes), are observed at the same location as high Fe concentrations (up to 71.2 mmol/L Fe(II) and 16.1 mmol/L Fe(III), respectively). In this zone, secondary Fe(III) hydroxides are depleted. Our data suggest that LMWCA may influence the mobility of iron in two ways. First, complexation of Fe(III), through formation of bidentate Fe(III)-LMWCA complexes (e.g., pyruvate, oxalate), may enhance the dissolution of Fe(III) (oxy)hydroxides or may prevent precipitation of Fe(III) (oxy)hydroxides. Soluble Fe(III) chelate complexes which may be mobilized downward and convert to Fe(II) by Fe(III) reducing bacteria. Second, monodentate LMWCA (e.g., acetate and formate) can be used by iron-reducing bacteria as electron donors (e.g., Acidophilum spp.), with ferric iron as the electron acceptor. These processes may, in part, explain the low abundances

Crucial advantages of tail use in the evolution of vertebrate terrestrial locomotion

NASA Astrophysics Data System (ADS)

Astley, Henry; McInroe, Benjamin; Kawano, Sandy; Blob, Rick; Goldman, Daniel

In the invasion of terrestrial environment, the first tetrapods faced the challenge of locomotion on flowable substrates (e.g. sand and mud), sometimes oriented at inclines. Although the morphology of many early tetrapods is known, robotic studies have revealed that effective locomotion on these substrates also depends strongly upon kinematics; slight differences in movements of the same appendage can lead to success or failure. Using a model organism (the mudskipper) and a robotic physical model, we demonstrate how muscular tails provided critical locomotor advantages on granular substrates that the first invaders of land likely encountered. Mudskippers use their tails for additional propulsion with increasing frequency as the slope of the granular material increases, and the decline in locomotor performance with slope is shallower when the tail is used. Experiments with a robotic model of the mudskipper showed that, while the tail did not always provide a benefit to locomotion, use of the tail made the robot's performance more robust, achieving effective locomotion on a wider range of slopes, limb postures and foot placements. These results suggest that, rather than simply being an inert appendage, the tails of early tetrapods were vital to their first forays into terrestrial habitats.

Biological effects of long term fine limestone tailings discharge in a fjord ecosystem.

PubMed

Brooks, Lucy; Melsom, Fredrik; Glette, Tormod

2015-07-15

Benthic infaunal data collected from 1993 to 2010 were analysed to examine the effect of long term discharge of fine limestone tailings on macrofaunal species assemblages in a fjord. Relative distance from the outfall and proportion of fine tailings in the sediment were correlated with benthic community structure. Diversity decreased with increasing proportion of fine tailings. Biological Traits Analysis (BTA) was used to explore the temporal and spatial effects of the tailings gradient on macrofaunal functional attributes. BTA revealed that all stations along a pressure gradient of fine limestone tailings were dominated by free-living species. As the proportion of fine tailings in the sediment increased, there was an increase in fauna that were smaller, highly mobile, living on or nearer the surface sediment, with shorter lifespans. There was a decrease in permanent tube dwellers, those fauna with low or no mobility, that live deeper in the sediment and have longer lifespans (>5 yrs). Copyright © 2015 Elsevier Ltd. All rights reserved.

Theoretical aerodynamic characteristics of a family of slender wing-tail-body combinations

NASA Technical Reports Server (NTRS)

Lomax, Harvard; Byrd, Paul F

1951-01-01

The aerodynamic characteristics of an airplane configuration composed of a swept-back, nearly constant chord wing and a triangular tail mounted on a cylindrical body are presented. The analysis is based on the assumption that the free-stream Mach number is near unity or that the configuration is slender. The calculations for the tail are made on the assumption that the vortex system trailing back from the wing is either a sheet lying entirely in the plane of the flat tail surface or has completely "rolled up" into two point vortices that lie either in, above, or below the plane of the tail surface.

VIEW OF BOEING 737200 FUSELAGE FROM TOP LEVEL OF TAIL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF BOEING 737-200 FUSELAGE FROM TOP LEVEL OF TAIL DOCK AND. A NEW SAFETY CABLE FROM THE TAIL DOCK WILL ALLOW INSPECTORS TO WALK UP AND DOWN THE FUSELAGE TO CHECK FOR CRACKS OR MISSING FASTENERS. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

Assessment of factors affecting micropropagation and ex vitro acclimatization of Nyctanthes arbor-tristis L.

PubMed

Jahan, Anushi Arjumend; Anis, M; Aref, I M

2011-03-01

Rapid differentiation of multiple shoots was observed in 94% of nodal explants of one year old Nyctanthes arbor-tristis L. plants. Shoot bud induction and multiplication took place on Murashige and Skoog (MS) medium supplemented with two cytokinins, i.e. Benzyladenine (BA) or Kinetin (Kn) either alone or in combination with different auxins, indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) or α-naphthalene acetic acid (NAA). Between different media, pH levels and growth regulators tried, the optimum condition for maximum regenerative response was obtained on MS + Kn (2.5 μM) + N AA (0.5 μM) media at 5.8 pH, forming cultures with 23.26 ± 0.89 number of shoots and 6.36 ± 0.80 cm shoot length after 8 weeks of culture. Histological sections confirmed the formation of multiple buds from nodal explants. Rooting was achieved ex vitro by dipping the basal ends of microshoots in 200 μM IBA for 30 min followed by their transplantation in sterile soilrite. The plantlets with well-developed shoot and root system were successfully established in garden soil and grown outside in a greenhouse with a 80% survival rate.

A Yurok Story: How the Animals Got Their Tails.

ERIC Educational Resources Information Center

Tripp, Maria

This story was told to the author by her grandmother, a Yurok born at Pecwan in 1898. Long ago, at a council meeting, the animals decided to ask the Great Creator for tails. He agreed and promised to give each animal a tail the next morning. The first animal to get up would have first choice. Coyote built a big fire and tried hard to stay awake…

Double streams of protons in the distant geomagnetic tail

NASA Technical Reports Server (NTRS)

Villante, U.; Lazarus, A. J.

1975-01-01

Two intermingled streams of protons have been observed in the distant geomagnetic tail. The number densities of the two streams are comparable, and their velocity difference tends to lie along the field direction. The lower-velocity stream is probably composed of magnetosheath protons which have diffused through the boundary of the distant tail. The higher-velocity stream appears to originate in the field reversal region.

Correlation between length and tilt of lipid tails

NASA Astrophysics Data System (ADS)

Kopelevich, Dmitry I.; Nagle, John F.

2015-10-01

It is becoming recognized from simulations, and to a lesser extent from experiment, that the classical Helfrich-Canham membrane continuum mechanics model can be fruitfully enriched by the inclusion of molecular tilt, even in the fluid, chain disordered, biologically relevant phase of lipid bilayers. Enriched continuum theories then add a tilt modulus κθ to accompany the well recognized bending modulus κ. Different enrichment theories largely agree for many properties, but it has been noticed that there is considerable disagreement in one prediction; one theory postulates that the average length of the hydrocarbon chain tails increases strongly with increasing tilt and another predicts no increase. Our analysis of an all-atom simulation favors the latter theory, but it also shows that the overall tail length decreases slightly with increasing tilt. We show that this deviation from continuum theory can be reconciled by consideration of the average shape of the tails, which is a descriptor not obviously includable in continuum theory.

Mineralogical and geochemical characterization of arsenic in an abandoned mine tailings of Korea.

PubMed

Ahn, Joo Sung; Park, Young Seog; Kim, Ju-Yong; Kim, Kyoung-Woong

2005-04-01

The mineralogical and chemical characteristics of As solid phases in arsenic-rich mine tailings from the Nakdong As-Bi mine in Korea was investigated. The tailings generated from the ore roasting process contained 4.36% of As whereas the concentration was up to 20.2% in some tailings from the cyanidation process for the Au extraction. Thin indurated layers and other secondary precipitates had formed at the surfaces of the tailings piles and the As contents of the hardened layers varied from 2.87 to 16.0%. Scorodite and iron arsenate (Fe3AsO7) were the primary As-bearing crystalline minerals. Others such as arsenolamprite, bernardite and titanium oxide arsenate were also found. The amorphous As-Fe phases often showed framboidal aggregates and gel type textures with desiccation cracks. Sequential extraction results also showed that 55.7-91.1% of the As in tailings were NH(4)-oxalate extractable As, further confirmed the predominance of amorphous As-Fe solid phases. When the tailings were equilibrated with de-ionized water, the solution exhibited extremely acidic conditions (pH 2.01-3.10) and high concentrations of dissolved As (up to 29.5 mg L(-1)), indicating high potentials for As to be released during rainfall events. The downstream water was affected by drainage from tailings and contained 12.7-522 microg L(-1) of As. The amorphous As-Fe phases in tailings have not entirely been stabilized through the long term natural weathering processes. To remediate the environmental harms they had caused, anthropogenic interventions to stabilize or immobilize As in the tailings pile should be explored.

Automated registration of tail bleeding in rats.

PubMed

Johansen, Peter B; Henriksen, Lars; Andresen, Per R; Lauritzen, Brian; Jensen, Kåre L; Juhl, Trine N; Tranholm, Mikael

2008-05-01

An automated system for registration of tail bleeding in rats using a camera and a user-designed PC-based software program has been developed. The live and processed images are displayed on the screen and are exported together with a text file for later statistical processing of the data allowing calculation of e.g. number of bleeding episodes, bleeding times and bleeding areas. Proof-of-principle was achieved when the camera captured the blood stream after infusion of rat whole blood into saline. Suitability was assessed by recording of bleeding profiles in heparin-treated rats, demonstrating that the system was able to capture on/off bleedings and that the data transfer and analysis were conducted successfully. Then, bleeding profiles were visually recorded by two independent observers simultaneously with the automated recordings after tail transection in untreated rats. Linear relationships were found in the number of bleedings, demonstrating, however, a statistically significant difference in the recording of bleeding episodes between observers. Also, the bleeding time was longer for visual compared to automated recording. No correlation was found between blood loss and bleeding time in untreated rats, but in heparinized rats a correlation was suggested. Finally, the blood loss correlated with the automated recording of bleeding area. In conclusion, the automated system has proven suitable for replacing visual recordings of tail bleedings in rats. Inter-observer differences can be eliminated, monotonous repetitive work avoided, and a higher through-put of animals in less time achieved. The automated system will lead to an increased understanding of the nature of bleeding following tail transection in different rodent models.

The tail sheath structure of bacteriophage T4: a molecular machine for infecting bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aksyuk, Anastasia A.; Leiman, Petr G.; Kurochkina, Lidia P.

2009-07-22

The contractile tail of bacteriophage T4 is a molecular machine that facilitates very high viral infection efficiency. Its major component is a tail sheath, which contracts during infection to less than half of its initial length. The sheath consists of 138 copies of the tail sheath protein, gene product (gp) 18, which surrounds the central non-contractile tail tube. The contraction of the sheath drives the tail tube through the outer membrane, creating a channel for the viral genome delivery. A crystal structure of about three quarters of gp18 has been determined and was fitted into cryo-electron microscopy reconstructions of themore » tail sheath before and after contraction. It was shown that during contraction, gp18 subunits slide over each other with no apparent change in their structure.« less

RICO Graduate Student Research Flight: The Island Tail Objective

NASA Astrophysics Data System (ADS)

Small, J. D.; Anderson-Bereznicki, S. D.; Medeiros, B.; Nuijens, L.; Henry, C. K.; O'Donnell, D. M.; Morales, F.; Shen, H.

2005-12-01

The Rain in Cumulus over the Ocean (RICO) project was an intensive field project aimed to study and understand precipitation processes in trade wind cumulus. The project took place from Nov 23, 2004 until Jan 25, 2005 on two small islands of the Lesser Antilles, Antigua and Barbuda, where trade wind cumulus fields frequently occur during suppressed wintertime conditions. RICO provided a unique combination of research and education by offering the RICO Graduate Seminar Series and the development and implementation of a graduate student designed and directed research flight. One of the main goals of the graduate student research flight was to allow graduate students to participate in the process of developing a research flight plan and identifying scientific goals and objectives first-hand. Added benefits included the possibility of addressing scientific questions not included in the main RICO objectives. This also involved collaboration when discussing different ideas and initiatives and the full development of all stages of the research flight including the coordination of two research aircraft (NCAR-C130, University of Wyoming King Air), one research vessel (RV Seward Johnson), S-Pol radar site and real time operations center satellite information. Seventeen graduate students from both the US and Europe developed two different plans to be presented to RICO project principle investigators; both of which were approved. The island tail objective aimed at characterizing the line of clouds known as 'island tails' that frequently form off the leeward coast of the Caribbean islands. This objective was successful in its implementation on Jan 18, 2005 with measurements made in vigorous, waterspout producing tail clouds immediately downwind of Barbuda. The investigation of these 'tails' fills a void in current cloud physics research since it is the first time this ubiquitous feature of trade-wind islands has been the focus of careful study. Scientific questions to be

The longest faun tail forming dreadlocks with underlying spina bifida occulta.

PubMed

Brar, Balvinder Kaur; Mahajan, Bharat Bhushan; Mittal, Jyotisterna

2013-04-15

Spina bifida is a developmental anomaly characterized by defective closure of the bony encasement of the spinal cord through which the spinal cord and meninges may or may not protrude. We report a rare case of a very long faun tail, which was in the form of a 20 inch long tail originating from the lumbosacral area in a rhomboidal pattern, measuring 10 x 8 inches. The case is being reported for its rare presentation of a 20 inch long faun tail with underlying spina bifida occulta.