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Sample records for short-tailed opossum monodelphis

  1. A three-dimensional stereotaxic atlas of the gray short-tailed opossum (Monodelphis domestica) brain.

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    Majka, Piotr; Chlodzinska, Natalia; Turlejski, Krzysztof; Banasik, Tomasz; Djavadian, Ruzanna L; Węglarz, Władysław P; Wójcik, Daniel K

    2018-05-01

    The gray short-tailed opossum (Monodelphis domestica) is a small marsupial gaining recognition as a laboratory animal in biomedical research. Despite numerous studies on opossum neuroanatomy, a consistent and comprehensive neuroanatomical reference for this species is still missing. Here we present the first three-dimensional, multimodal atlas of the Monodelphis opossum brain. It is based on four complementary imaging modalities: high resolution ex vivo magnetic resonance images, micro-computed tomography scans of the cranium, images of the face of the cutting block, and series of sections stained with the Nissl method and for myelinated fibers. Individual imaging modalities were reconstructed into a three-dimensional form and then registered to the MR image by means of affine and deformable registration routines. Based on a superimposition of the 3D images, 113 anatomical structures were demarcated and the volumes of individual regions were measured. The stereotaxic coordinate system was defined using a set of cranial landmarks: interaural line, bregma, and lambda, which allows for easy expression of any location within the brain with respect to the skull. The atlas is released under the Creative Commons license and available through various digital atlasing web services.

  2. Synaptology of luteinizing hormone-releasing hormone (LHRH)-immunoreactive cells in the nervus terminalis of the gray short-tailed opossum (Monodelphis domestica).

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    Zheng, L M; Pfaff, D W; Schwanzel-Fukuda, M

    1990-05-08

    Light and electron microscopic immunocytochemistry were used to examine the structure of LHRH neurons and fibers in the nervus terminalis of the gray short-tailed opossum (Monodelphis domestica). LHRH-immunoreactive neurons and fibers form a loose plexus within the fascicular network of the ganglion terminale on the median surface of the olfactory bulb. There are at least two populations of LHRH-immunoreactive neurons within the network of the ganglion terminale: fusiform and round neurons similar to those described in the forebrain. At the ultrastructural level, axosomatic and axodendritic contacts were seen between LHRH-immunoreactive and nonimmunoreactive elements in the ganglion terminale. These contacts were classified as 1) synaptic input, with asymmetric synapses seen between a nonimmunoreactive axon terminal and a LHRH-immunoreactive cell body or a nonimmunoreactive axon terminal and a LHRH-immunoreactive dendritic process. 2) synaptic output, with symmetric synapses seen between LHRH-immunoreactive and nonimmunoreactive processes. This study is the first systematic examination of the ultrastructure of the LHRH-immunoreactive neurons and their synaptic contacts in the nervus terminalis. The possible integrative roles for this LHRH-immunoreactive system are discussed.

  3. Effect of lead exposure on spatial learning and running speed in the short-tailed opossum, Monodelphis domestica (Didelphidae).

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    Punzo, F; Farmer, C

    2004-01-01

    Studies were conducted to assess the spatial learning ability in adult males of the short-tailed opossum, Monodelphis domestica using a T-maze, complex maze and elevated radial 8-arm maze. This is the first study of maze learning in opossums. In the T-maze, the performance of these animals improved over an 8-day training period. Eighty percent of the subjects initially trained to turn to the right for food reinforcement reached criterion (80% correct responses) by day 3 and all reached criterion by day 4. Reversal training (subjects then trained to turn to the left) was more difficult and required 8 days for all subjects to reach criterion. In the complex maze, 89% of the animals achieved the criterion level of performance (3 consecutive trials with 5 or fewer errors) on the eighth day of training and all reached criterion by day 10. The relative importance of intramaze vs. extramaze cues in directing choice behavior was investigated in the radial arm maze. A discrimination procedure was used which selectively rewarded subjects for following only one set of cues. Animals in the intramaze group obtained a food pellet from a cup at the end of each arm. In the extramaze group, the food cups were placed on a small platform just beyond the end of each arm. All subjects were initially trained to visit each arm with the maze in a fixed position (controls) and did so within 15 test sessions. Following these initial trials, the maze was rotated to a different position after each choice. For subjects in the intramaze group, the food moved in conjunction with the rotation of the arms thereby increasing the relevance of intramaze cues. In the extramaze group, extramaze cues became more important because the food remained on the platforms in the same position in the room. Animals in the extramaze group performed significantly better than chance whereas the intramaze subjects did not. This indicates that intramaze cues are not as important as extramaze cues for accurate choice

  4. Parotid Salivary Gland Basal Cell Adenocarcinoma in a Big-eared Opossum (Didelphis aurita).

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    Díaz-Delgado, J; Coimbra, A A C; Dos Santos-Cirqueira, C; Sanches, T C; Guerra, J M; de Oliveira, A S; Di Loretto, C; Zwarg, T; Ressio, R; Rivas, L; Sansone, M; Nagamori, F O; Kanamura, C; Gonçalves, P S; Fernandes, N C C A; Groch, K R; Catão-Dias, J L

    2018-02-01

    The opossum (family Didelphidae) is a marsupial endemic to the Americas. Apart from the South American short-tailed opossum (Monodelphis domestica) and the Virginia opossum (Didelphis virginiana), there is considerable lack of knowledge about the health and diseases of most opossum species. Among these, the big-eared opossum (Didelphis aurita) is found in Argentina, Brazil and Paraguay. Natural and experimental studies have shown this species to be susceptible to infectious agents with zoonotic potential and the animals may play a role in transmission of such agents. However, neoplasia appears to be uncommon in this species. We describe the gross, microscopical and immunohistochemical features of a parotid salivary gland basal cell adenocarcinoma in a free-living big-eared opossum. This case represents the first report of salivary gland neoplasia in opossums. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Ontogeny of cholecystokinin-like immunoreactivity in the Brazilian opossum brain.

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    Fox, C A; Jeyapalan, M; Ross, L R; Jacobson, C D

    1991-12-17

    We have studied the anatomical distribution of cholecystokinin-like immunoreactive (CCK-IR) somata and fibers in the brain of the adult and developing Brazilian short-tailed opossum, Monodelphis domestica. Animals ranged in age from the day of birth (1PN) to young adulthood (180PN). A nickel enhanced, avidin-biotin, indirect immunohistochemical technique was used to identify CCK-IR structures. Somata containing CCK immunoreactivity were observed in the cerebral cortex, hippocampus, hypothalamus, thalamus, midbrain, and brainstem in the adult. Cholecystokinin immunoreactive fibers had a wide distribution in the adult Monodelphis brain. The only major region of the brain that did not contain CCK-IR fibers was the cerebellum. The earliest expression of CCK immunoreactivity was found in fibers in the dorsal brainstem of 5-day-old opossum pups. It is possible that the CCK-IR fibers in the brainstem at 5PN are of vagal origin. Cholecystokinin immunoreactive somata were observed in the brainstem on 10PN. The CCK-IR cell bodies observed in the brainstem at 10PN may mark the first expression of CCK-IR elements intrinsic to the brain. A broad spectrum of patterns of onset of CCK expression was observed in the opossum brain. The early occurrence and varied ontogenesis of CCK-IR structures indicates CCK may be involved in the function of a variety of circuits from the brainstem to the cerebral cortex. The early expression of CCK-IR structures in the dorsal brainstem suggests that CCK may modulate feeding behavior in the Monodelphis neonate. Cholecystokinin immunoreactivity in forebrain structures such as the suprachiasmatic nucleus, medial preoptic area, thalamus and cortical structures indicates that CCK may also be involved in circadian rhythmicity, reproductive functions, as well as the state of arousal of the Brazilian opossum. The ontogenic timing of CCK immunoreactivity in specific circuitry also indicates that CCK expression does not occur simultaneously throughout the

  6. Facial Mechanosensory Influence on Forelimb Movement in Newborn Opossums, Monodelphis domestica.

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    Marie-Josée Desmarais

    Full Text Available The opossum, Monodelphis domestica, is born very immature but crawls, unaided, with its forelimbs (FL from the mother's birth canal to a nipple where it attaches to pursue its development. What sensory cues guide the newborn to the nipple and trigger its attachment to it? Previous experiments showed that low intensity electrical stimulation of the trigeminal ganglion induces FL movement in in vitro preparations and that trigeminal innervation of the facial skin is well developed in the newborn. The skin does not contain Vater-Pacini or Meissner touch corpuscles at this age, but it contains cells which appear to be Merkel cells (MC. We sought to determine if touch perceived by MC could exert an influence on FL movements. Application of the fluorescent dye AM1-43, which labels sensory cells such as MC, revealed the presence of a large number of labeled cells in the facial epidermis, especially in the snout skin, in newborn opossums. Moreover, calibrated pressure applied to the snout induced bilateral and simultaneous electromyographic responses of the triceps muscle in in vitro preparations of the neuraxis and FL from newborn. These responses increase with stimulation intensity and tend to decrease over time. Removing the facial skin nearly abolished these responses. Metabotropic glutamate 1 receptors being involved in MC neurotransmission, an antagonist of these receptors was applied to the bath, which decreased the EMG responses in a reversible manner. Likewise, bath application of the purinergic type 2 receptors, used by AM1-43 to penetrate sensory cells, also decreased the triceps EMG responses. The combined results support a strong influence of facial mechanosensation on FL movement in newborn opossums, and suggest that this influence could be exerted via MC.

  7. Convergent and divergent evolution of genomic imprinting in the marsupial Monodelphis domestica

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    Das Radhika

    2012-08-01

    Full Text Available Abstract Background Genomic imprinting is an epigenetic phenomenon resulting in parent-of-origin specific monoallelic gene expression. It is postulated to have evolved in placental mammals to modulate intrauterine resource allocation to the offspring. In this study, we determined the imprint status of metatherian orthologues of eutherian imprinted genes. Results L3MBTL and HTR2A were shown to be imprinted in Monodelphis domestica (the gray short-tailed opossum. MEST expressed a monoallelic and a biallelic transcript, as in eutherians. In contrast, IMPACT, COPG2, and PLAGL1 were not imprinted in the opossum. Differentially methylated regions (DMRs involved in regulating imprinting in eutherians were not found at any of the new imprinted loci in the opossum. Interestingly, a novel DMR was identified in intron 11 of the imprinted IGF2R gene, but this was not conserved in eutherians. The promoter regions of the imprinted genes in the opossum were enriched for the activating histone modification H3 Lysine 4 dimethylation. Conclusions The phenomenon of genomic imprinting is conserved in Therians, but the marked difference in the number and location of imprinted genes and DMRs between metatherians and eutherians indicates that imprinting is not fully conserved between the two Therian infra-classes. The identification of a novel DMR at a non-conserved location as well as the first demonstration of histone modifications at imprinted loci in the opossum suggest that genomic imprinting may have evolved in a common ancestor of these two Therian infra-classes with subsequent divergence of regulatory mechanisms in the two lineages.

  8. Photoreactivation of UV-induced pyrimidine dimers and erythema in the marsupial Monodelphis domestica

    International Nuclear Information System (INIS)

    Ley, R.D.

    1985-01-01

    Post-UV treatment of the gray, short-tailed opossum Monodelphis domestica with photoreactivating light (320-400 nm) suppressed the appearance of UV-induced erythema as evidenced by an increase in the dose of UV required to elicit an erythemal response. Pre-UV exposure to photoreactivating light had no effect on the UV induction of erythema. The dose-response for the photoreversal of pyrimidine dimers in epidermal DNA of M. domestica was similar to that for the photoreactivation of erythema induction. These data not only support the notion that DNA is the primary chromophore involved in the induction of erythema but also identify pyrimidine dimers as the major DNA change responsible for its induction. These results also identify M. domestica as a useful whole-animal system with which to determine the role of pyrimidine dimers in other photobiological responses of mammalian skin

  9. Weight-bearing locomotion in the developing opossum, Monodelphis domestica following spinal transection: remodeling of neuronal circuits caudal to lesion.

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    Wheaton, Benjamin J; Noor, Natassya M; Whish, Sophie C; Truettner, Jessie S; Dietrich, W Dalton; Zhang, Moses; Crack, Peter J; Dziegielewska, Katarzyna M; Saunders, Norman R

    2013-01-01

    Complete spinal transection in the mature nervous system is typically followed by minimal axonal repair, extensive motor paralysis and loss of sensory functions caudal to the injury. In contrast, the immature nervous system has greater capacity for repair, a phenomenon sometimes called the infant lesion effect. This study investigates spinal injuries early in development using the marsupial opossum Monodelphis domestica whose young are born very immature, allowing access to developmental stages only accessible in utero in eutherian mammals. Spinal cords of Monodelphis pups were completely transected in the lower thoracic region, T10, on postnatal-day (P)7 or P28 and the animals grew to adulthood. In P7-injured animals regrown supraspinal and propriospinal axons through the injury site were demonstrated using retrograde axonal labelling. These animals recovered near-normal coordinated overground locomotion, but with altered gait characteristics including foot placement phase lags. In P28-injured animals no axonal regrowth through the injury site could be demonstrated yet they were able to perform weight-supporting hindlimb stepping overground and on the treadmill. When placed in an environment of reduced sensory feedback (swimming) P7-injured animals swam using their hindlimbs, suggesting that the axons that grew across the lesion made functional connections; P28-injured animals swam using their forelimbs only, suggesting that their overground hindlimb movements were reflex-dependent and thus likely to be generated locally in the lumbar spinal cord. Modifications to propriospinal circuitry in P7- and P28-injured opossums were demonstrated by changes in the number of fluorescently labelled neurons detected in the lumbar cord following tracer studies and changes in the balance of excitatory, inhibitory and neuromodulatory neurotransmitter receptors' gene expression shown by qRT-PCR. These results are discussed in the context of studies indicating that although

  10. Weight-bearing locomotion in the developing opossum, Monodelphis domestica following spinal transection: remodeling of neuronal circuits caudal to lesion.

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    Benjamin J Wheaton

    Full Text Available Complete spinal transection in the mature nervous system is typically followed by minimal axonal repair, extensive motor paralysis and loss of sensory functions caudal to the injury. In contrast, the immature nervous system has greater capacity for repair, a phenomenon sometimes called the infant lesion effect. This study investigates spinal injuries early in development using the marsupial opossum Monodelphis domestica whose young are born very immature, allowing access to developmental stages only accessible in utero in eutherian mammals. Spinal cords of Monodelphis pups were completely transected in the lower thoracic region, T10, on postnatal-day (P7 or P28 and the animals grew to adulthood. In P7-injured animals regrown supraspinal and propriospinal axons through the injury site were demonstrated using retrograde axonal labelling. These animals recovered near-normal coordinated overground locomotion, but with altered gait characteristics including foot placement phase lags. In P28-injured animals no axonal regrowth through the injury site could be demonstrated yet they were able to perform weight-supporting hindlimb stepping overground and on the treadmill. When placed in an environment of reduced sensory feedback (swimming P7-injured animals swam using their hindlimbs, suggesting that the axons that grew across the lesion made functional connections; P28-injured animals swam using their forelimbs only, suggesting that their overground hindlimb movements were reflex-dependent and thus likely to be generated locally in the lumbar spinal cord. Modifications to propriospinal circuitry in P7- and P28-injured opossums were demonstrated by changes in the number of fluorescently labelled neurons detected in the lumbar cord following tracer studies and changes in the balance of excitatory, inhibitory and neuromodulatory neurotransmitter receptors' gene expression shown by qRT-PCR. These results are discussed in the context of studies indicating

  11. Exogenous retinoic acid induces digit reduction in opossums (Monodelphis domestica) by disrupting cell death and proliferation, and apical ectodermal ridge and zone of polarizing activity function.

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    Molineaux, Anna C; Maier, Jennifer A; Schecker, Teresa; Sears, Karen E

    2015-03-01

    Retinoic acid (RA) is a vitamin A derivative. Exposure to exogenous RA generates congenital limb malformations (CLMs) in species from frogs to humans. These CLMs include but are not limited to oligodactyly and long-bone hypoplasia. The processes by which exogenous RA induces CLMs in mammals have been best studied in mouse, but as of yet remain unresolved. We investigated the impact of exogenous RA on the cellular and molecular development of the limbs of a nonrodent model mammal, the opossum Monodelphis domestica. Opossums exposed to exogenous retinoic acid display CLMs including oligodactly, and results are consistent with opossum development being more susceptible to RA-induced disruptions than mouse development. Exposure of developing opossums to exogenous RA leads to an increase in cell death in the limb mesenchyme that is most pronounced in the zone of polarizing activity, and a reduction in cell proliferation throughout the limb mesenchyme. Exogenous RA also disrupts the expression of Shh in the zone of polarizing activity, and Fgf8 in the apical ectodermal ridge, and other genes with roles in the regulation of limb development and cell death. Results are consistent with RA inducing CLMs in opossum limbs by disrupting the functions of the apical ectodermal ridge and zone of polarizing activity, and driving an increase in cell death and reduction of cell proliferation in the mesenchyme of the developing limb. © 2015 Wiley Periodicals, Inc.

  12. Experimental infection of two South American reservoirs with four distinct strains of Trypanosoma cruzi

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    Roellig, Dawn M.; McMillan, Katherine; Ellis, Angela E.; Vandeberg, John L.; Champagne, Donald E.; Yabsley, Michael J.

    2010-01-01

    SUMMARY Trypanosoma cruzi (Tc), the causative agent of Chagas disease, is a diverse species with 2 primary genotypes, TcI and TcII, with TcII further subdivided into 5 subtypes (IIa–e). This study evaluated infection dynamics of 4 genetically and geographically diverse T. cruzi strains in 2 South American reservoirs, degus (Octodon degus) and grey short-tailed opossums (Monodelphis domestica). Based on prior suggestions of a genotype-host association, we hypothesized that degus (placental) would more readily become infected with TcII strains while short-tailed opossums (marsupial) would be a more competent reservoir for a TcI strain. Individuals (n = 3) of each species were intraperitoneally inoculated with T. cruzi trypomastigotes of TcIIa [North America (NA)-raccoon (Procyon lotor) origin], TcI [NA-Virginia opossum (Didelphis virginiana)], TcIIb [South America (SA)-human], TcIIe (SA-Triatoma infestans), or both TcI and TcIIa. Parasitaemias in experimentally infected degus peaked earlier (7–14 days post-inoculation (p.i.)) compared with short-tailed opossums (21–84 days p.i.). Additionally, peak parasitaemias were higher in degus; however, the duration of detectable parasitaemias for all strains, except TcIIa, was greater in short-tailed opossums. Infections established in both host species with all genotypes, except for TcIIa, which did not establish a detectable infection in short-tailed opossums. These results indicate that both South American reservoirs support infections with these isolates from North and South America; however, infection dynamics differed with host and parasite strain. PMID:20128943

  13. Spontaneous development of full weight-supported stepping after complete spinal cord transection in the neonatal opossum, Monodelphis domestica.

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    Benjamin J Wheaton

    Full Text Available Spinal cord trauma in the adult nervous system usually results in permanent loss of function below the injury level. The immature spinal cord has greater capacity for repair and can develop considerable functionality by adulthood. This study used the marsupial laboratory opossum Monodelphis domestica, which is born at a very early stage of neural development. Complete spinal cord transection was made in the lower-thoracic region of pups at postnatal-day 7 (P7 or P28, and the animals grew to adulthood. Injury at P7 resulted in a dense neuronal tissue bridge that connected the two ends of the cord; retrograde neuronal labelling indicated that supraspinal and propriospinal innervation spanned the injury site. This repair was associated with pronounced behavioural recovery, coordinated gait and an ability to use hindlimbs when swimming. Injury at P28 resulted in a cyst-like cavity encased in scar tissue forming at the injury site. Using retrograde labelling, no labelled brainstem or propriospinal neurons were found above the lesion, indicating that detectable neuronal connectivity had not spanned the injury site. However, these animals could use their hindlimbs to take weight-supporting steps but could not use their hindlimbs when swimming. White matter, demonstrated by Luxol Fast Blue staining, was present in the injury site of P7- but not P28-injured animals. Overall, these studies demonstrated that provided spinal injury occurs early in development, regrowth of supraspinal innervation is possible. This repair appears to lead to improved functional outcomes. At older ages, even without detectable axonal growth spanning the injury site, substantial development of locomotion was still possible. This outcome is discussed in conjunction with preliminary findings of differences in the local propriospinal circuits following spinal cord injury (demonstrated with fluororuby labelling, which may underlie the weight bearing locomotion observed in the

  14. Amelotin Gene Structure and Expression during Enamel Formation in the Opossum Monodelphis domestica

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    Gasse, Barbara; Liu, Xi; Corre, Erwan; Sire, Jean-Yves

    2015-01-01

    Amelotin (AMTN) is an ameloblast-secreted protein that belongs to the secretory calcium-binding phosphoprotein family, which also includes the enamel matrix proteins amelogenin, ameloblastin and enamelin. Although AMTN is supposed to play an important role in enamel formation, data were long limited to the rodents, in which it is expressed during the maturation stage. Recent comparative studies in sauropsids and amphibians revealed that (i) AMTN was expressed earlier, i.e. as soon as ameloblasts are depositing the enamel matrix, and (ii) AMTN structure was different, a change which mostly resulted from an intraexonic splicing in the large exon 8 of an ancestral mammal. The present study was performed to know whether the differences in AMTN structure and expression in rodents compared to non-mammalian tetrapods dated back to an early ancestral mammal or were acquired later in mammalian evolution. We sequenced, assembled and screened the jaw transcriptome of a neonate opossum Monodelphis domestica, a marsupial. We found two AMTN transcripts. Variant 1, representing 70.8% of AMTN transcripts, displayed the structure known in rodents, whereas variant 2 (29.2%) exhibited the nonmammalian tetrapod structure. Then, we studied AMTN expression during amelogenesis in a neonate specimen. We obtained similar data as those reported in rodents. These findings indicate that more than 180 million years ago, before the divergence of marsupials and placentals, changes occurred in AMTN function and structure. The spatiotemporal expression was delayed to the maturation stage of amelogenesis and the intraexonic splicing gave rise to isoform 1, encoded by variant 1 and lacking the RGD motif. The ancestral isoform 2, housing the RGD, was initially conserved, as demonstrated here in a marsupial, then secondarily lost in the placental lineages. These findings bring new elements towards our understanding of the non-prismatic to prismatic enamel transition that occurred at the onset of

  15. Amelotin Gene Structure and Expression during Enamel Formation in the Opossum Monodelphis domestica.

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    Barbara Gasse

    Full Text Available Amelotin (AMTN is an ameloblast-secreted protein that belongs to the secretory calcium-binding phosphoprotein family, which also includes the enamel matrix proteins amelogenin, ameloblastin and enamelin. Although AMTN is supposed to play an important role in enamel formation, data were long limited to the rodents, in which it is expressed during the maturation stage. Recent comparative studies in sauropsids and amphibians revealed that (i AMTN was expressed earlier, i.e. as soon as ameloblasts are depositing the enamel matrix, and (ii AMTN structure was different, a change which mostly resulted from an intraexonic splicing in the large exon 8 of an ancestral mammal. The present study was performed to know whether the differences in AMTN structure and expression in rodents compared to non-mammalian tetrapods dated back to an early ancestral mammal or were acquired later in mammalian evolution. We sequenced, assembled and screened the jaw transcriptome of a neonate opossum Monodelphis domestica, a marsupial. We found two AMTN transcripts. Variant 1, representing 70.8% of AMTN transcripts, displayed the structure known in rodents, whereas variant 2 (29.2% exhibited the nonmammalian tetrapod structure. Then, we studied AMTN expression during amelogenesis in a neonate specimen. We obtained similar data as those reported in rodents. These findings indicate that more than 180 million years ago, before the divergence of marsupials and placentals, changes occurred in AMTN function and structure. The spatiotemporal expression was delayed to the maturation stage of amelogenesis and the intraexonic splicing gave rise to isoform 1, encoded by variant 1 and lacking the RGD motif. The ancestral isoform 2, housing the RGD, was initially conserved, as demonstrated here in a marsupial, then secondarily lost in the placental lineages. These findings bring new elements towards our understanding of the non-prismatic to prismatic enamel transition that occurred at

  16. Myosin isoform fiber type and fiber size in the tail of the Virginia opossum (Didelphis virginiana).

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    Hazimihalis, P J; Gorvet, M A; Butcher, M T

    2013-01-01

    Muscle fiber type is a well studied property in limb muscles, however, much less is understood about myosin heavy chain (MHC) isoform expression in caudal muscles of mammalian tails. Didelphid marsupials are an interesting lineage in this context as all species have prehensile tails, but show a range of tail-function depending on either their arboreal or terrestrial locomotor habits. Differences in prehensility suggest that MHC isoform fiber types may also be different, in that terrestrial opossums may have a large distribution of oxidative fibers for object carrying tasks instead of faster, glycolytic fiber types expected in mammals with long tails. To test this hypothesis, MHC isoform fiber type and their regional distribution (proximal/transitional/distal) were determined in the tail of the Virginia opossum (Didelphis virginiana). Fiber types were determined by a combination of myosin-ATPase histochemistry, immunohistochemistry, and SDS-PAGE. Results indicate a predominance of the fast MHC-2A and -2X isoforms in each region of the tail. The presence of two fast isoforms, in addition to the slow MHC-1 isoform, was confirmed by SDS-PAGE analysis. The overall MHC isoform fiber type distribution for the tail was: 25% MHC-1, 71% MHC-2A/X hybrid, and 4% MHC-1/2A hybrid. Oxidative MHC-2A/X isoform fibers were found to be relatively large in cross-section compared to slow, oxidative MHC-1 and MHC-1/2A hybrid fibers. A large percentage of fast MHC-2A/X hybrids fibers may be suggestive of an evolutionary transition in MHC isoform distribution (fast-to-slow fiber type) in the tail musculature of an opossum with primarily a terrestrial locomotor habit and adaptive tail-function. Copyright © 2012 Wiley Periodicals, Inc.

  17. Trypanosoma (Megatrypanum saloboense n. sp. (Kinetoplastida: Trypanosomatidae parasite of Monodelphis emiliae (Marsupiala: Didelphidae from Amazonian Brazil

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    Lainson R.

    2008-06-01

    Full Text Available Trypanosoma (Megatrypanum saloboense n. sp., is described in the Brazilian opossum Monodelphis emiliae (Thomas, 1912 from primary forest in the Salobo area of the Serra dos Carajás (6° S, 50° 18′ W Pará State, North Brazil. Two morphologically different trypomastigotes were noted. Slender forms, regarded as immature parasites, have a poorly developed undulating membrane adhering closely to the body: large, broad forms with a well developed membrane are considered to be the mature trypomastigotes and have a mean total length of 71.2 μm (62.4-76.2 and a width of 6.1 (5.0-8.0. Infections studied in two opossums were of very low parasitaemia. The large size of T. (M. saloboense readily distinguishes it from the two previously described members of the subgenus Megatrypanum of neotropical marsupials, T. (M. freitasi Régo et al., 1957 of Didelphis azarae and D. marsupialis, and T. (M. samueli Mello, 1977 of Monodelphis domesticus, which measure only 49.0-51.5 μm and 42.4 μm respectively. No infections were obtained in hamsters inoculated with triturated liver and spleen from one infected M. emiliae, or in laboratory mice inoculated with epimastigotes from a blood-agar culture. No division stages could be detected in the internal organs or the peripheral blood.

  18. Reconstructing an ancestral mammalian immune supercomplex from a marsupial major histocompatibility complex.

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    Katherine Belov

    2006-03-01

    Full Text Available The first sequenced marsupial genome promises to reveal unparalleled insights into mammalian evolution. We have used the Monodelphis domestica (gray short-tailed opossum sequence to construct the first map of a marsupial major histocompatibility complex (MHC. The MHC is the most gene-dense region of the mammalian genome and is critical to immunity and reproductive success. The marsupial MHC bridges the phylogenetic gap between the complex MHC of eutherian mammals and the minimal essential MHC of birds. Here we show that the opossum MHC is gene dense and complex, as in humans, but shares more organizational features with non-mammals. The Class I genes have amplified within the Class II region, resulting in a unique Class I/II region. We present a model of the organization of the MHC in ancestral mammals and its elaboration during mammalian evolution. The opossum genome, together with other extant genomes, reveals the existence of an ancestral "immune supercomplex" that contained genes of both types of natural killer receptors together with antigen processing genes and MHC genes.

  19. Evaluation of the Chagas Stat-Paktm Assay for Detection of Trypanosoma cruzi Antibodies in Wildlife Reservoirs

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    Yabsley, Michael J.; Brown, Emily L.; Roellig, Dawn M.

    2010-01-01

    An immunochromatographic assay (Chagas Stat-Pak™) was evaluated for the detection of Trypanosoma cruzi antibodies in 4 species of wildlife reservoirs. Antibodies to T. cruzi were detected in raccoons (Procyon lotor) (naturally and experimentally infected) and degus (Octodon degu) (experimentally-infected) using the Chagas Stat-Pak. In naturally exposed wild raccoons, the Chagas Stat-Pak had a sensitivity and specificity of 66.7–80.0% and 96.3%, respectively. Compared with indirect immunofluorescent antibody assay results, serocon-version as determined by Chagas Stat-Pak was delayed for experimentally infected raccoons, but occurred sooner in experimentally infected degus. The Chagas Stat-Pak did not detect antibodies in naturally or experimentally infected Virginia opossums (Didelphis virginiana) or in experimentally infected short-tailed opossums (Monodelphis domestica). These data suggest that the Chagas Stat-Pak might be useful in field studies of raccoons and degus when samples would not be available for more-conventional serologic assays. Because this assay did not work on either species of marsupial, the applicability of the assay should be examined before it is used in other wild species. PMID:19016578

  20. Prevalence of Trypanosoma cruzi and organ alterations in Virginia opossums (Didelphis virginiana) from western Mexico - short communication.

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    Carnevali, Vincenzo; Nogueda-Torres, Benjamín; Villagrán-Herrera, María E; De Diego-Cabrera, José A; Rocha-Chávez, Gonzalo; Martínez-Ibarra, José A

    2017-12-01

    Small populations of Virginia opossum (Didelphis virginiana) in western Mexico are endangered by hunting and natural predators as well as by different kinds of diseases. After two serological analyses using Serodia® latex particle agglutination and indirect haemagglutination (IHA) tests, 35 (53.03%) of 66 collected opossums in two small towns in western Mexico were positive for the presence of Trypanosoma cruzi. Twenty-eight of the 35 seropositive opossums had pathological lesions: 11 had changes in only one organ, 13 in two organs, and four had pathological changes in three organs. Splenomegaly was the most common finding in the examined opossums, followed by hepatomegaly. These potentially fatal pathological changes could contribute to the scarcity of the opossum population, even leading to the extinction of this species in western Mexico.

  1. The transcriptome of the Didelphis virginiana opossum kidney OK proximal tubule cell line.

    Science.gov (United States)

    Eshbach, Megan L; Sethi, Rahil; Avula, Raghunandan; Lamb, Janette; Hollingshead, Deborah J; Finegold, David N; Locker, Joseph D; Chandran, Uma R; Weisz, Ora A

    2017-09-01

    The OK cell line derived from the kidney of a female opossum Didelphis virginiana has proven to be a useful model in which to investigate the unique regulation of ion transport and membrane trafficking mechanisms in the proximal tubule (PT). Sequence data and comparison of the transcriptome of this cell line to eutherian mammal PTs would further broaden the utility of this culture model. However, the genomic sequence for D. virginiana is not available and although a draft genome sequence for the opossum Monodelphis domestica (sequenced in 2012 by the Broad Institute) exists, transcripts sequenced from both species show significant divergence. The M. domestica sequence is not highly annotated, and the majority of transcripts are predicted rather than experimentally validated. Using deep RNA sequencing of the D. virginiana OK cell line, we characterized its transcriptome via de novo transcriptome assembly and alignment to the M. domestica genome. The quality of the de novo assembled transcriptome was assessed by the extent of homology to sequences in nucleotide and protein databases. Gene expression levels in the OK cell line, from both the de novo transcriptome and genes aligned to the M. domestica genome, were compared with publicly available rat kidney nephron segment expression data. Our studies demonstrate the expression in OK cells of numerous PT-specific ion transporters and other key proteins relevant for rodent and human PT function. Additionally, the sequence and expression data reported here provide an important resource for genetic manipulation and other studies on PT cell function using these cells. Copyright © 2017 the American Physiological Society.

  2. Surveillance and movements of Virginia opossum (Didelphis virginiana) in the bovine tuberculosis region of Michigan.

    Science.gov (United States)

    Walter, W D; Fischer, J W; Anderson, C W; Marks, D R; Deliberto, T; Robbe-Austerman, S; Vercauteren, K C

    2013-07-01

    Wildlife reservoir hosts of bovine tuberculosis (bTB) include Eurasian badgers (Meles meles) and brushtail possum (Trichosurus vulpecula) in the UK and New Zealand, respectively. Similar species warrant further investigation in the northern lower peninsula of Michigan, USA due to the continued presence of bTB on cattle farms. Most research in Michigan, USA has focused on interactions between white-tailed deer (Odocoileus virginianus) and cattle (Bos taurus) for the transmission of the infectious agent of bTB, Mycobacterium bovis, due to high deer densities and feeding practices. However, limited data are available on medium-sized mammals such as Virginia opossum (Didelphis virginiana; hereafter referred to as opossum) and their movements and home range in Michigan near cattle farms. We conducted surveillance of medium-sized mammals on previously depopulated cattle farms for presence of M. bovis infections and equipped opossum with Global Positioning System (GPS) technology to assess potential differences in home range between farms inside and outside the bTB core area that has had cattle test positive for M. bovis. On farms inside the bTB core area, prevalence in opossum was comparable [6%, 95% confidence interval (CI) 2.0-11.0] to prevalence in raccoon (Procyon lotor; 4%, 95% CI 1.0-9.0, P=0.439) whereas only a single opossum tested positive for M. bovis on farms outside the bTB core area. The prevalence in opossum occupying farms that had cattle test positive for M. bovis was higher (6.4%) than for opossum occupying farms that never had cattle test positive for M. bovis (0.9%, P=0.01). Mean size of home range for 50% and 95% estimates were similar by sex (P=0.791) both inside or outside the bTB core area (P=0.218). Although surveillance efforts and home range were not assessed on the same farms, opossum use of farms near structures was apparent as was selection for farms over surrounding forested habitats. The use of farms, stored feed, and structures by opossum

  3. Metal accumulation in wild-caught opossum.

    Science.gov (United States)

    Lockhart, J Mitchell; Siddiqui, Samreen; Loughry, W J; Bielmyer-Fraser, Gretchen K

    2016-06-01

    The Virginia opossum (Didelphis virginiana) is widespread in the USA, ranging south through Latin America. The ecology of opossums is such that they are in frequent contact with soils, suggesting that they may function as a valuable bioindicator for chemical contamination in terrestrial environments. Surprisingly, there have been virtually no toxicology studies on opossums. Here, we provide the first analysis of metal contaminants in opossum liver tissues. Liver samples were obtained from 471 opossums, collected from 2003 to 2006, at four sites in North Florida and South Georgia, USA, and concentrations of copper, lead, nickel, selenium, and zinc were measured. We found little evidence of age differences in the concentration of any of the metals. However, there were at least some significant differences between years, males and females, and between sites for each metal, although the pattern of these differences was not always consistent across metals. Concentrations of metals in liver tissue were positively correlated with one another, primarily of each metal (except Pb) with zinc. Reference levels of metal contaminants are not available for opossums, but concentrations of Cu, Ni, Pb, and Zn in our samples were for the most part significantly higher than those reported from liver tissues of nine-banded armadillos (Dasypus novemcinctus) collected at the same sites and in the same years. Data from other small mammals studied elsewhere further indicate that metal concentrations in opossums were high, but at this time, it is not possible to determine if these elevated levels generated toxicity. The substantial temporal and spatial variation we found in metal concentrations suggests that determination of baseline levels for opossums may not be straightforward. Nonetheless, this is the first study quantifying metal accumulation in the livers of Didelphis virginiana and, as such, provides an important starting point for future research.

  4. Prevalence of sarcocystis species sporocysts in wild-caught opossums (Didelphis virginiana).

    Science.gov (United States)

    Dubey, J P

    2000-08-01

    Sarcocystis sporocysts were found in intestinal scrapings from 24 (54.5%) of 44 opossums (Didelphis virginiana). The number of sporocysts varied from a few (< 10,000) to 245 million. Sporocysts from 23 of 24 opossums were fed to captive budgerigars (Melopsittacus undulatas), and the inocula from 21 opossums were infective, indicating the presence of Sarcocystis falcatula. Sporocysts from 24 opossums were fed to gamma-interferon-knockout (KO) or nude mice; inocula from 14 opossums were infective to mice. Sarcocystis neurona was detected in tissues of KO mice by specific staining with anti-S. neurona antibodies, and the parasite was cultured in vitro from the brains of KO mice fed sporocysts from 8 opossums. Sarcocystis speeri was identified by specific staining with anti-S. speeri antibodies in tissues of KO mice fed inocula from 8 opossums; 3 opossums had mixed S. neurona and S. speeri infections. Thus, the prevalences of sporocysts of different species of Sarcocystis in opossums were: S. falcatula 21 of 44 (47.7%), S. neurona 8 of 44 (18.1%), and S. speeri 8 of 44 (18.1%) opossums. Sarcocystis neurona alone was found in 1 opossum, and S. speeri alone was found in 1 opossum. Mixed Sarcocystis infections were present in 21 opossums.

  5. Genetically different isolates of Trypanosoma cruzi elicit different infection dynamics in raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana).

    Science.gov (United States)

    Roellig, Dawn M; Ellis, Angela E; Yabsley, Michael J

    2009-12-01

    Trypanosoma cruzi is a genetically and biologically diverse species. In the current study we determined T. cruzi infection dynamics in two common North American reservoirs, Virginia opossums (Didelphis virginiana) and raccoons (Procyon lotor). Based on previous molecular and culture data from naturally-exposed animals, we hypothesised that raccoons would have a longer patent period than opossums, and raccoons would be competent reservoirs for both genotypes T. cruzi I (TcI) and TcIIa, while opossums would only serve as hosts for TcI. Individuals (n=2 or 3) of each species were inoculated with 1x10(6) culture-derived T. cruzi trypomastigotes of TcIIa (North American (NA) - raccoon), TcI (NA - opossum), TcIIb (South American - human), or both TcI and TcIIa. Parasitemias in opossums gradually increased and declined rapidly, whereas parasitemias peaked sooner in raccoons and they maintained relatively high parasitemia for 5weeks. Raccoons became infected with all three T. cruzi strains, while opossums only became infected with TcI and TcIIb. Although opossums were susceptible to TcIIb, infection dynamics were dramatically different compared with TcI. Opossums inoculated with TcIIb seroconverted, but parasitemia duration was short and only detectable by PCR. In addition, raccoons seroconverted sooner (3-7days post inoculation) than opossums (10days post inoculation). These data suggest that infection dynamics of various T. cruzi strains can differ considerably in different wildlife hosts.

  6. Bacterial Clearance and Endocarditis in American Opossums

    Science.gov (United States)

    Musher, Daniel M.; Richie, Yvonne

    1974-01-01

    The American opossum is the only experimental animal that regularly develops bacterial endocarditis spontaneously. There was no relation between the ability of opossums to clear bacteria from the bloodstream and the subsequent development of endocarditis. PMID:4208530

  7. Cloning of the short-tailed Gyeongju Donggyeong dog via SCNT: conserving phenotypic inheritance.

    Science.gov (United States)

    Choi, Yoo Bin; Kim, Geon A; Oh, Hyun Ju; Kim, Min Jung; Jo, Young Kwang; Setyawan, Erif Maha Nugraha; Lee, Seok Hee; Lee, Byeong Chun

    2016-02-01

    Somatic cell nuclear transfer is a useful tool to maintain genetic information of animals. The Gyeongju Donggyeong dog is a breed registered as natural monument in Korea. The unique feature of the Donggyeong dog is its tail, as the Donggyeong dog can be classified as either short tailed or tailless. The aim of this study was to preserve the Donggyeong dog's unique feature by cloning. Fibroblasts were obtained from a short-tailed Donggyeong dog. In vivo matured oocytes were enucleated, microinjected with a donor cell and fused electrically. Reconstructed embryos were transferred to six recipient dogs. One surrogate became pregnant, and one short-tailed Donggyeong dog was delivered. This study demonstrated that the phenotype of the Donggyeong dog could be conserved by somatic cell nuclear transfer.

  8. Experimental aerosol inoculation of Mycobacterium bovis in North American opossums (Didelphis virginiana).

    Science.gov (United States)

    Fitzgerald, Scott D; Zwick, Laura S; Diegel, Kelly L; Berry, Dale E; Church, Steven V; Sikarskie, James G; Kaneene, John B; Reed, Willie M

    2003-04-01

    The goal of this study was to evaluate the susceptibility of North American opossums (Didelphis virginiana) to aerosol inoculation of Mycobacterium bovis at two dose levels in order to gain information on disease pathogenesis, fecal shedding of the organism, and the potential role that opossums play in the spread of this disease in nature. Six opossums received high dose (1 x 10(7) colony forming units (cfu) by aerosol inoculation, six opossums received low dose (1 x 10(3) cfu inoculation, and six opossums were sham-inoculated with sterile water and served as controls. Lungs were the most frequently infected tissues, with nine of 12 inoculated opossums positive for M. bovis on culture. Gross lesions consisted of multifocal pneumonia and enlarged lymph nodes. Microscopically, granulomatous pneumonia and granulomatous lymphadenitis associated with acid-fast bacilli were present in eight of 12 inoculated opossums. Fecal shedding of M. bovis was uncommon at both inoculation doses. While opossums were highly susceptible to aerosol inoculation of M. bovis, they did not become emaciated or develop widely disseminated lesions. From this study, opossums may transmit tuberculosis by aerosol infection to other opossums in close contact and serve as a source of infection to carnivores that feed upon them, however, transmission of the disease to large herbivores by fecal shedding or direct contact may be less likely.

  9. Behavioral and nutritional aspects of the Virginian opossum (Didelphis virginiana).

    Science.gov (United States)

    McRuer, David L; Jones, Kenneth D

    2009-05-01

    Virginia opossums are widely distributed throughout the United States, except in the most arid regions, and wild individuals are commonly brought to practitioners for medical attention. Opossums' popularity as pets seems to be growing, and it is likely that pet opossums will be more common in veterinary practice. Clinicians must be aware of natural opossum behaviors so that thorough physical examination and diagnostic procedures can be performed on injured patients. For animals kept captive long-term or as pets, veterinarians must understand proper nutrition and nutritional disorders, such as secondary nutritional hyperparathyroidism, obesity, and dental disease, to properly treat this species.

  10. Prevalence of Sarcocystis neurona sporocysts in opossums (Didelphis virginiana) from rural Mississippi.

    Science.gov (United States)

    Dubey, J P; Black, S S; Rickard, L G; Rosenthal, B M; Lindsay, D S; Shen, S K; Kwok, O C; Hurst, G; Rashmir-Raven, A

    2001-02-26

    Sarcocystis species sporocysts were found in intestinal scrapings from 24 of 72 opossums (Didelphis virginiana) from rural Mississippi. The number of sporocysts in each opossum varied from a few ( virginiana suggests that this opossum constitutes an ample reservoir of infection in the southern United States.

  11. Expression and cellular distribution of ubiquitin in response to injury in the developing spinal cord of Monodelphis domestica.

    Directory of Open Access Journals (Sweden)

    Natassya M Noor

    Full Text Available Ubiquitin, an 8.5 kDa protein associated with the proteasome degradation pathway has been recently identified as differentially expressed in segment of cord caudal to site of injury in developing spinal cord. Here we describe ubiquitin expression and cellular distribution in spinal cord up to postnatal day P35 in control opossums (Monodelphis domestica and in response to complete spinal transection (T10 at P7, when axonal growth through site of injury occurs, and P28 when this is no longer possible. Cords were collected 1 or 7 days after injury, with age-matched controls and segments rostral to lesion were studied. Following spinal injury ubiquitin levels (western blotting appeared reduced compared to controls especially one day after injury at P28. In contrast, after injury mRNA expression (qRT-PCR was slightly increased at P7 but decreased at P28. Changes in isoelectric point of separated ubiquitin indicated possible post-translational modifications. Cellular distribution demonstrated a developmental shift between earliest (P8 and latest (P35 ages examined, from a predominantly cytoplasmic immunoreactivity to a nuclear expression; staining level and shift to nuclear staining was more pronounced following injury, except 7 days after transection at P28. After injury at P7 immunostaining increased in neurons and additionally in oligodendrocytes at P28. Mass spectrometry showed two ubiquitin bands; the heavier was identified as a fusion product, likely to be an ubiquitin precursor. Apparent changes in ubiquitin expression and cellular distribution in development and response to spinal injury suggest an intricate regulatory system that modulates these responses which, when better understood, may lead to potential therapeutic targets.

  12. The short-tailed Albatross, Diomedea albatrus, its status, distribution and natural history

    Science.gov (United States)

    Hasegawa, H.; DeGange, A.R.

    1982-01-01

    The Short-tailed Albatross (Diomedea albatrus) is presently an Endangered Species that was formerly abundant in the North Pacific. Owing to the activities of feather hunters operating on the albatross's nesting grounds for a 50-year period in the late 19th and early 20th centuries, the species was almost reduced to extinction. The Short-tailed Albatross is the largest of the three species of Diomedea that breed in the North Pacific (Table 1) and when mature is the only albatross in the North Pacific with a white back.

  13. Forelimb preferences in quadrupedal marsupials and their implications for laterality evolution in mammals

    Science.gov (United States)

    2013-01-01

    Background Acquisition of upright posture in evolution has been argued to facilitate manual laterality in primates. Owing to the high variety of postural habits marsupials can serve as a suitable model to test whether the species-typical body posture shapes forelimb preferences in non-primates or this phenomenon emerged only in the course of primate evolution. In the present study we aimed to explore manual laterality in marsupial quadrupeds and compare them with the results in the previously studied bipedal species. Forelimb preferences were assessed in captive grey short-tailed opossum (Monodelphis domestica) and sugar glider (Petaurus breviceps) in four different types of unimanual behaviour per species, which was not artificially evoked. We examined the possible effects of sex, age and task, because these factors have been reported to affect motor laterality in placental mammals. Results In both species the direction of forelimb preferences was strongly sex-related. Male grey short-tailed opossums showed right-forelimb preference in most of the observed unimanual behaviours, while male sugar gliders displayed only a slight, not significant rightward tendency. In contrast, females in both species exhibited consistent group-level preference of the left forelimb. We failed to reveal significant differences in manual preferences between tasks of potentially differing complexity: reaching a stable food item and catching live insects, as well as between the body support and food manipulation. No influence of subjects’ age on limb preferences was found. Conclusions The direction of sex-related differences in the manual preferences found in quadrupedal marsupials seems to be not typical for placental mammals. We suggest that the alternative way of interhemispheric connection in absence of corpus callosum may result in a fundamentally distinct mechanism of sex effect on limb preferences in marsupials compared to placentals. Our data confirm the idea that non

  14. The immune response of adult opossums (Didelphis virginiana) to the bacteriophage f2

    Science.gov (United States)

    Rowlands, D. T.

    1970-01-01

    Humoral immunity to the bacteriophage f2 was studied in adult opossums (Didelphis virginiana) and their responses were compared to those in New Zealand White rabbits. Antibodies were found in the serum of opossums 7 days after the subcutaneous injection of the antigen and peak antibody responses were observed between 10 and 21 days after immunization. A second injection of antigen resulted in increased antibody activity. In either case the level of serum antibody reached in opossums was less than that in rabbits. More striking, however, was the relatively slow conversion from γM to γG antibodies in opossums. The course of the immune response in adult opossums was more nearly like that of cold-blooded vertebrates than that of eutherian mammals. PMID:5416636

  15. Prevalence of Sarcocystis species sporocysts in Northern Virginia opossums (Didelphis virginiana).

    Science.gov (United States)

    Elsheikha, Hany M; Murphy, Alice J; Mansfield, Linda S

    2004-08-01

    A total of 206 Virginia opossums ( Didelphis virginiana) collected from the mid-Michigan region, United States, during a period extending from 1996 to 2002 were sampled for the presence of Sarcocystis spp sporocysts. All isolates were phenotypically identified as Sarcocystis spp and genotyped to the species level by PCR-based techniques. The overall prevalence of Sarcocystis spp in opossums was 18% (37/206). The prevalence of Sarcocystis spp differed significantly with age ( P<0.001) and adult opossums were more commonly infected (14.6%; 30/206) than juveniles (3.4%; 7/206). No significant difference in the prevalence of Sarcocystis spp infection was observed between male and female ( P<0.15). The highest prevalence was recorded during summer (9.2%; 19/206). PCR-RFLP analyses demonstrated the majority of Sarcocystis isolates to be S. neurona, with some animals co-infected with sporocysts of S. falcatula. Out of the 37 Sarcocystis-infected opossums, 23 (62%) had sporocysts of S. neurona only, four (11%) had sporocysts of S. falcatula only, and eight (22%) had a mixture of S. neurona and S. falcatula sporocysts. These findings indicate that mixed Sarcocystis infections in opossums are common. The propensity for Sarcocystis spp to co-exist in the opossum gut enhances dissemination and environmental contamination with these coccidia. Additionally, this increases the chance for sexual recombination between Sarcocystis spp, given the proclivity of these species to reproduce sexually at high numbers in the intestinal cells of their definitive host.

  16. Whole Genome Sequencing Identifies a Missense Mutation in HES7 Associated with Short Tails in Asian Domestic Cats.

    Science.gov (United States)

    Xu, Xiao; Sun, Xin; Hu, Xue-Song; Zhuang, Yan; Liu, Yue-Chen; Meng, Hao; Miao, Lin; Yu, He; Luo, Shu-Jin

    2016-08-25

    Domestic cats exhibit abundant variations in tail morphology and serve as an excellent model to study the development and evolution of vertebrate tails. Cats with shortened and kinked tails were first recorded in the Malayan archipelago by Charles Darwin in 1868 and remain quite common today in Southeast and East Asia. To elucidate the genetic basis of short tails in Asian cats, we built a pedigree of 13 cats segregating at the trait with a founder from southern China and performed linkage mapping based on whole genome sequencing data from the pedigree. The short-tailed trait was mapped to a 5.6 Mb region of Chr E1, within which the substitution c. 5T > C in the somite segmentation-related gene HES7 was identified as the causal mutation resulting in a missense change (p.V2A). Validation in 245 unrelated cats confirmed the correlation between HES7-c. 5T > C and Chinese short-tailed feral cats as well as the Japanese Bobtail breed, indicating a common genetic basis of the two. In addition, some of our sampled kinked-tailed cats could not be explained by either HES7 or the Manx-related T-box, suggesting at least three independent events in the evolution of domestic cats giving rise to short-tailed traits.

  17. A tale too long for a tail too short? : identification of characteristics in pigs related to tail biting and other oral manipulations directed at conspecifics

    NARCIS (Netherlands)

    Ursinus, W.W.

    2014-01-01

    Ursinus, W.W. (2014). A tale too long for a tail too short? Identification of

    characteristics in pigs related to tail biting and other oral manipulations directed

    at conspecifics. PhD thesis, Wageningen University, The Netherlands.

    Tail biting in pigs, i.e. the chewing on and

  18. Trypanosoma cruzi in the anal glands of urban opossums: I- isolation and experimental infections

    Directory of Open Access Journals (Sweden)

    S Urdaneta-Morales

    1996-08-01

    Full Text Available Opossums (Didelphis marsupialis captured in intensely urbanized areas of the city of Caracas, Venezuela, were found infected with Trypanosoma cruzi. The developmental cycle of trypomastigote-epimastigote-metacyclic infective trypomastigote, usually occurring in the intestine of the triatomine vector, was taking place in the anal odoriferous glands of the opossums. Material from the glands, inoculated in young, healthy opossums and white mice by different routes, subcutaneously, intraperitoneally, orally, and into the eye, induced T. cruzi infections in all animals. Parasitemia, invasion of cardiac and skeletal muscle, and intracellular multiplication of amastigotes were observed. Inoculation of metacyclics from anal glands, cultured in LIT medium, gave equivalent results. All opossums survived; all mice died. Excreta of opossums may thus transmit Chagas' disease by contamination, even in urban areas where insect vectors are not present.

  19. Extreme Temperature Exceedances Change more Rapidly Under Future Warming in Regions of non-Gaussian Short Temperature Distribution Tails

    Science.gov (United States)

    Loikith, P. C.; Neelin, J. D.; Meyerson, J.

    2017-12-01

    Regions of shorter-than-Gaussian warm and cold side temperature distribution tails are shown to occur in spatially coherent patterns in the current climate. Under such conditions, warming may be manifested in more complex ways than if the underlying distribution were close to Gaussian. For example, under a uniform warm shift, the simplest prototype for future warming, a location with a short warm side tail would experience a greater increase in extreme warm exceedances compared to if the distribution were Gaussian. Similarly, for a location with a short cold side tail, a uniform warm shift would result in a rapid decrease in extreme cold exceedances. Both scenarios carry major societal and environmental implications including but not limited to negative impacts on human and ecosystem health, agriculture, and the economy. It is therefore important for climate models to be able to realistically reproduce short tails in simulations of historical climate in order to boost confidence in projections of future temperature extremes. Overall, climate models contributing to the fifth phase of the Coupled Model Intercomparison Project capture many of the principal observed regions of short tails. This suggests the underlying dynamics and physics occur on scales resolved by the models, and helps build confidence in model projections of extremes. Furthermore, most GCMs show more rapid changes in exceedances of extreme temperature thresholds in regions of short tails. Results therefore suggest that the shape of the tails of the underlying temperature distribution is an indicator of how rapidly a location will experience changes to extreme temperature occurrence under future warming.

  20. Lack of Sarcocystis neurona antibody response in Virginia opossums (Didelphis virginiana) fed Sarcocystis neurona-infected muscle tissue.

    Science.gov (United States)

    Cheadle, M A; Lindsay, D S; Greiner, E C

    2006-06-01

    Serum was collected from laboratory-reared Virginia opossums (Didelphis virginiana) to determine whether experimentally infected opossums shedding Sarcocystis neurona sporocysts develop serum antibodies to S. neurona merozoite antigens. Three opossums were fed muscles from nine-banded armadillos (Dasypus novemcinctus), and 5 were fed muscles from striped skunks (Mephitis mephitis). Serum was also collected from 26 automobile-killed opossums to determine whether antibodies to S. neurona were present in these opossums. Serum was analyzed using the S. neurona direct agglutination test (SAT). The SAT was modified for use with a filter paper collection system. Antibodies to S. neurona were not detected in any of the serum samples from opossums, indicating that infection in the opossum is localized in the small intestine. Antibodies to S. neurona were detected in filter-paper-processed serum samples from 2 armadillos naturally infected with S. neurona.

  1. Cone pigments in a North American marsupial, the opossum (Didelphis virginiana).

    Science.gov (United States)

    Jacobs, Gerald H; Williams, Gary A

    2010-05-01

    Only two of the four cone opsin gene families found in vertebrates are represented in contemporary eutherian and marsupial species. Recent genetic studies of two species of South American marsupial detected the presence of representatives from two of the classes of cone opsin genes and the structures of these genes predicted cone pigments with respective peaks in the ultraviolet and long-wavelength portions of the spectrum. The Virginia opossum (Didelphis virginiana), a profoundly nocturnal animal, is the only marsupial species found in North America. The prospects for cone-based vision in this species were examined through recordings of the electroretinogram (ERG), a commonly examined retinal response to photic stimulation. Recorded under flickering-light conditions that elicit signals from cone photoreceptors, the spectral sensitivity of the opossum eye is well accounted for by contributions from the presence of a single cone pigment having peak absorption at 561-562 nm. A series of additional experiments that employed various chromatic adaptation paradigms were conducted in a search for possible contributions from a second (short-wavelength sensitive) cone pigment. We found no evidence that such a mechanism contributes to the ERG in this marsupial.

  2. A review of Sarcocystis spp. shed by opossums (Didelphis spp. in Brazil

    Directory of Open Access Journals (Sweden)

    Samantha Yuri Oshiro Branco Valadas

    2016-08-01

    Full Text Available South American opossums are the definitive hosts of Sarcocystis neurona, Sarcocystis falcatula, Sarcocystis speeri and Sarcocystis lindsayi. The sporocysts of these species of Sarcocystis are morphologically similar and methods like infectivity and pathogenicity for intermediate hosts (immunodeficient mice and psittacine birds and molecular tools are used for identification. Opossums are synanthropic wild animals, and widely distributed in Brazilian territory. Previous studies have shown high environmental contamination with S. neurona sporocysts in several Brazilian regions. This paper reviews information on Sarcocystis spp. shed by various opossum species and its occurrence in Brazil.

  3. oPOSSUM: integrated tools for analysis of regulatory motif over-representation

    Science.gov (United States)

    Ho Sui, Shannan J.; Fulton, Debra L.; Arenillas, David J.; Kwon, Andrew T.; Wasserman, Wyeth W.

    2007-01-01

    The identification of over-represented transcription factor binding sites from sets of co-expressed genes provides insights into the mechanisms of regulation for diverse biological contexts. oPOSSUM, an internet-based system for such studies of regulation, has been improved and expanded in this new release. New features include a worm-specific version for investigating binding sites conserved between Caenorhabditis elegans and C. briggsae, as well as a yeast-specific version for the analysis of co-expressed sets of Saccharomyces cerevisiae genes. The human and mouse applications feature improvements in ortholog mapping, sequence alignments and the delineation of multiple alternative promoters. oPOSSUM2, introduced for the analysis of over-represented combinations of motifs in human and mouse genes, has been integrated with the original oPOSSUM system. Analysis using user-defined background gene sets is now supported. The transcription factor binding site models have been updated to include new profiles from the JASPAR database. oPOSSUM is available at http://www.cisreg.ca/oPOSSUM/ PMID:17576675

  4. Experimental inoculation of North American opossums (Didelphis virginiana) with Mycobacterium bovis.

    Science.gov (United States)

    Diegel, Kelly L; Fitzgerald, Scott D; Berry, Dale E; Church, Steven V; Reed, Willie M; Sikarskie, James G; Kaneene, John B

    2002-04-01

    Eight North American opossums (Didelphis virginiana) were inoculated with 1 x 10(5) colony forming units of Mycobacterium bovis to investigate their potential as reservoir hosts for bovine tuberculosis in Michigan. Four animals received this dose orally and four were inoculated intramuscularly (i.m.). In each group, two animals were euthanized 1 mo postinoculation (PI) and two at 2 mo PI. Four control animals were housed separately and sacrificed in the same manner as those inoculated. One of four orally inoculated opossums and three of four i.m.-inoculated opossums were positive for M. bovis by culture of tissues obtained at necropsy. The oral recipient had positive cultures from intestine and pooled lymphoid samples. Pooled lymphoid samples were positive in three i.m.-inoculated animals and two of these also had positive liver and lung cultures. One animal with gross and histologic lesions compatible with tuberculosis had negative tissue cultures. The findings suggest that opossums are susceptible to M. bovis infection by multiple routes, although their relative susceptibility compared to true reservoir hosts appears to be low.

  5. The development of enamel tubules during the formation of enamel in the marsupial Monodelphis domestica.

    OpenAIRE

    Sasagawa, I; Ferguson, M W

    1991-01-01

    In Monodelphis domestica, although both processes from odontoblasts and projections from ameloblasts were found in developing enamel, the majority of the contents of enamel tubules were probably processes that originated from odontoblasts. Processes from odontoblasts penetrating into enamel touched part of the ameloblasts in the stage of enamel formation. No specialised cell junctions were seen at the adherence between the two. There were no enamel tubules in the aprismatic and pseudoprismati...

  6. Postmortem scavenging by the Virginia opossum (Didelphis virginiana): Impact on taphonomic assemblages and progression.

    Science.gov (United States)

    King, Kama A; Lord, Wayne D; Ketchum, Heather R; O'Brien, R Christopher

    2016-09-01

    The Virginia opossum (Didelphis virginiana) is a highly active scavenger whose behavior has significant impacts on rates of decomposition and skeletonization, which have previously not been addressed. In this study, scavenging by the opossum led to the skeletonization of carcasses in half of the accumulated degree days (ADD) of a comparable non-scavenged control carcass. Opossums used body orifices, as well as natural tears caused by the decomposition process, to access internal tissues and consume them. This activity resulted in little movement of the carcass and the retained appearance of natural undisturbed decomposition. This concealed activity has the potential to cause drastically incorrect estimates of time since deposition and post-mortem interval. Scavenging by opossums was also found to leave distinct tooth mark and other defects on bone, which have not been previously distinguished in the literature. This research suggests, beyond effects on PMI, that scavenging by opossums has been historically overlooked and misattributed to canid scavengers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. Prevalence and risk factors associated with Sarcocystis neurona infections in opossums (Didelphis virginiana) from central California.

    Science.gov (United States)

    Rejmanek, Daniel; Vanwormer, Elizabeth; Miller, Melissa A; Mazet, Jonna A K; Nichelason, Amy E; Melli, Ann C; Packham, Andrea E; Jessup, David A; Conrad, Patricia A

    2009-12-03

    Sarcocystis neurona, a protozoal parasite shed by opossums (Didelphis virginiana), has been shown to cause significant morbidity and mortality in horses, sea otters, and other marine mammals. Over the course of 3 years (fall 2005-summer 2008), opossums from central California were tested for infection with S. neurona. Of 288 opossums sampled, 17 (5.9%) were infected with S. neurona based on the molecular characterization of sporocysts from intestinal scrapings or feces. Risk factors evaluated for association with S. neurona infection in opossums included: age, sex, location, season, presence of pouch young in females, concomitant infection, and sampling method (live-trapped or traffic-killed). Multivariate logistic regression analysis identified that opossums in the Central Valley were 9 times more likely to be infected than those near the coast (p=0.009). Similarly, opossum infection was 5 times more likely to be detected during the reproductive season (March-July; p=0.013). This first investigation of S. neurona infection prevalence and associated risk factors in opossums in the western United States can be used to develop management strategies aimed at reducing the incidence of S. neurona infections in susceptible hosts, including horses and threatened California sea otters (Enhydra lutris neries).

  8. Predictable hotspots and foraging habitat of the endangered short-tailed albatross (Phoebastria albatrus) in the North Pacific: Implications for conservation

    Science.gov (United States)

    Piatt, John F.; Wetzel, J.; Bell, K.; DeGange, A.R.; Balogh, G.R.; Drew, G.S.; Geernaert, T.; Ladd, C.; Byrd, G.V.

    2006-01-01

    The short-tailed albatross (Phoebastria albatrus) is a rare and endangered seabird that ranges widely over the northern North Pacific. Populations are slowly recovering but birds face several threats at sea, in particular the incidental capture of birds in long-line fisheries. Conservation efforts are hampered by a lack of information about the at-sea distribution of this species, especially knowledge of where it may predictably co-occur with long-line fishing effort. During 18 years of transiting the Aleutian Islands Unit of the Alaska Maritime National Wildlife Refuge on a research vessel, we observed short-tailed albatross on 65 occasions. They were consistently observed near Ingenstrem Rocks (Buldir Pass) in the western Aleutians and near Seguam Pass in the central Aleutians. Based on the oceanographic characteristics of the locations where we saw most of the birds, we hypothesized that short-tailed albatross “hotspots” were located where tidal currents and steep bottom topography generate strong vertical mixing along the Aleutian Archipelago. As a test of this hypothesis, we analyzed a database containing 1432 opportunistic observations of 2463 short-tailed albatross at sea in the North Pacific. These data showed that short-tailed albatross were closely associated with shelf-edge habitats throughout the northern Gulf of Alaska and Bering Sea. In addition to Ingenstrem Rocks and Seguam Pass, important hotspots for short-tailed albatross in the Aleutians included Near Strait, Samalga Pass, and the shelf-edge south of Umnak/Unalaska islands. In the Bering Sea, hotspots were located along margins of Zhemchug, St. Matthews and Pervenets canyons. Because these short-tailed albatross hotspots are predictable, they are also protectable by regulation of threatening activities at local spatial scales.

  9. Characterization of short- and long-term mechanical sensitisation following surgical tail amputation in pigs

    DEFF Research Database (Denmark)

    Di Giminiani, Pierpaolo; Edwards, Sandra A.; Malcolm, Emma M.

    2017-01-01

    -term (either eight or sixteen weeks post-surgery) phase of recovery. The influence of the degree of amputation on MNTs was also evaluated by comparing three different tail-resection treatments (intact, ‘short tail’, ‘long tail’). A significant reduction in MNTs one week following surgery suggests...... the occurrence of acute sensitisation. Long-term hypersensitivity was also observed in tail-resected pigs at either two or four months following surgery. Tail amputation in pigs appears to evoke acute and sustained changes in peripheral mechanical sensitivity, which resemble features of neuropathic pain reported...

  10. Experimental Aerosol Inoculation and Investigation of Potential Lateral Transmission of Mycobacterium bovis in Virginia Opossum (Didelphis virginiana).

    Science.gov (United States)

    Fenton, Karla A; Fitzgerald, Scott D; Bolin, Steve; Kaneene, John; Sikarskie, James; Greenwald, Rena; Lyashchenko, Konstantin

    2012-01-01

    An endemic focus of Mycobacterium bovis (M. bovis) infection in the state of Michigan has contributed to a regional persistence in the animal population. The objective of this study was to determine if Virginia opossums (Didelphis virginiana) contribute to disease persistence by experimentally assessing intraspecies lateral transmission. One wild caught pregnant female opossum bearing 11 joeys (young opossum) and one age-matched joey were obtained for the study. Four joeys were aerosol inoculated with M. bovis (inoculated), four joeys were noninoculated (exposed), and four joeys plus the dam were controls. Four replicate groups of one inoculated and one exposed joey were housed together for 45 days commencing 7 days after experimental inoculation. At day 84 opossums were sacrificed. All four inoculated opossums had a positive test band via rapid test, culture positive, and gross/histologic lesions consistent with caseogranulomatous pneumonia. The exposed and control groups were unremarkable on gross, histology, rapid test, and culture. In conclusion, M. bovis infection within the inoculated opossums was confirmed by gross pathology, histopathology, bacterial culture, and antibody tests. However, M. bovis was not detected in the control and exposed opossums. There was no appreciable lateral transmission of M. bovis after aerosol inoculation and 45 days of cohabitation between infected and uninfected opossums.

  11. Experimental Aerosol Inoculation and Investigation of Potential Lateral Transmission of Mycobacterium bovis in Virginia Opossum (Didelphis virginiana

    Directory of Open Access Journals (Sweden)

    Karla A. Fenton

    2012-01-01

    Full Text Available An endemic focus of Mycobacterium bovis (M. bovis infection in the state of Michigan has contributed to a regional persistence in the animal population. The objective of this study was to determine if Virginia opossums (Didelphis virginiana contribute to disease persistence by experimentally assessing intraspecies lateral transmission. One wild caught pregnant female opossum bearing 11 joeys (young opossum and one age-matched joey were obtained for the study. Four joeys were aerosol inoculated with M. bovis (inoculated, four joeys were noninoculated (exposed, and four joeys plus the dam were controls. Four replicate groups of one inoculated and one exposed joey were housed together for 45 days commencing 7 days after experimental inoculation. At day 84 opossums were sacrificed. All four inoculated opossums had a positive test band via rapid test, culture positive, and gross/histologic lesions consistent with caseogranulomatous pneumonia. The exposed and control groups were unremarkable on gross, histology, rapid test, and culture. In conclusion, M. bovis infection within the inoculated opossums was confirmed by gross pathology, histopathology, bacterial culture, and antibody tests. However, M. bovis was not detected in the control and exposed opossums. There was no appreciable lateral transmission of M. bovis after aerosol inoculation and 45 days of cohabitation between infected and uninfected opossums.

  12. Granulomatous pneumonia in the opossum (Didelphis virginiana) associated with an intracellular fungal agent.

    Science.gov (United States)

    Almgren, C M; McClure, D E

    2000-06-01

    Two of nine female opossums (Didelphis virginiana) in a closed breeding colony were submitted for necropsy due to a history of poor reproductive performance in the absence of overt clinical disease. On histologic examination, marked granulomatous to pyogranulomatous pneumonia was identified in these animals. Lung sections were stained with periodic acid-Schiff and Gomori's methenamine silver nitrate. Pulmonary lesions were characterized by large numbers of foamy macrophages within the alveoli and interstitium, prominent subpleural and peribronchiolar aggregates of histiocytes, and a few scattered lymphoid nodules. Numerous fungal organisms were evident within the cytoplasm of macrophages on impregnation of histologic sections with the aforementioned stains. Other inciting agents were not identified. A third opossum lacked pulmonary lesions, but had similar organisms within one auricular sebaceous gland/hair follicle without apparent reaction to the organisms. A fungal agent was associated with granulomatous pneumonia in the opossum, and comparison was made with endogenous lipid pneumonia previously described in opossums. These findings stress the importance of use of special stains and additional diagnostic techniques when prominent alveolar macrophage accumulation is present on histologic examination of the opossum lung.

  13. ABCB4 mediates diet-induced hypercholesterolemia in laboratory opossums[S

    OpenAIRE

    Chan, Jeannie; Mahaney, Michael C.; Kushwaha, Rampratap S.; VandeBerg, Jane F.; VandeBerg, John L.

    2010-01-01

    High-responding opossums are susceptible to developing hypercholesterolemia on a high-cholesterol diet, but low-responding opossums are resistant. The observation of low biliary cholesterol and low biliary phospholipids in high responders suggested that the ABCB4 gene affects response to dietary cholesterol. Two missense mutations (Arg29Gly and Ile235Leu) were found in the ABCB4 gene of high responders. High responders (ATHH strain) were bred with low responders (ATHE or ATHL strain) to produ...

  14. Tonawanda Creek, Genesee County, New York, Regional Flood Control. Final Environmental Impact Statement.

    Science.gov (United States)

    1981-11-01

    Long-tail Weasel : Mustela frenata Least Weasel : Mustela rixosa Mink : Mustela vison Eastern Skunk : Mephitis mephitis Red Fox : Vulpes fulva Gray Fo...environments and listed: (a) thickening of gill lamellae, (b) excessive mucous secretion, (c) abrasion of branchial epithelium, and (d) respiratory distress...Ranges Uhich May Include the Batavia Reservoir Compound Site Opossum : Didelphis marsupialis Raccoon : Procyon lotor Short-tail Weasel : Mustela erminea

  15. Structure and expression of two nuclear receptor genes in marsupials: insights into the evolution of the antisense overlap between the α-thyroid hormone receptor and Rev-erbα

    Directory of Open Access Journals (Sweden)

    Brown M Scott

    2010-12-01

    Full Text Available Abstract Background Alternative processing of α-thyroid hormone receptor (TRα, NR1A1 mRNAs gives rise to two functionally antagonistic nuclear receptors: TRα1, the α-type receptor, and TRα2, a non-hormone binding variant that is found only in mammals. TRα2 shares an unusual antisense coding overlap with mRNA for Rev-erbα (NR1D1, another nuclear receptor protein. In this study we examine the structure and expression of these genes in the gray short-tailed opossum, Monodelphis domestica, in comparison with that of eutherian mammals and three other marsupial species, Didelphis virginiana, Potorous tridactylus and Macropus eugenii, in order to understand the evolution and regulatory role of this antisense overlap. Results The sequence, expression and genomic organization of mRNAs encoding TRα1 and Rev-erbα are very similar in the opossum and eutherian mammals. However, the sequence corresponding to the TRα2 coding region appears truncated by almost 100 amino acids. While expression of TRα1 and Rev-erbα was readily detected in all tissues of M. domestica ages 0 days to 18 weeks, TRα2 mRNA was not detected in any tissue or stage examined. These results contrast with the widespread and abundant expression of TRα2 in rodents and other eutherian mammals. To examine requirements for alternative splicing of TRα mRNAs, a series of chimeric minigenes was constructed. Results show that the opossum TRα2-specific 5' splice site sequence is fully competent for splicing but the sequence homologous to the TRα2 3' splice site is not, even though the marsupial sequences are remarkably similar to core splice site elements in rat. Conclusions Our results strongly suggest that the variant nuclear receptor isoform, TRα2, is not expressed in marsupials and that the antisense overlap between TRα and Rev-erbα thus is unique to eutherian mammals. Further investigation of the TRα and Rev-erbα genes in marsupial and eutherian species promises to yield

  16. Structure and expression of two nuclear receptor genes in marsupials: insights into the evolution of the antisense overlap between the α-thyroid hormone receptor and Rev-erbα

    Science.gov (United States)

    2010-01-01

    Background Alternative processing of α-thyroid hormone receptor (TRα, NR1A1) mRNAs gives rise to two functionally antagonistic nuclear receptors: TRα1, the α-type receptor, and TRα2, a non-hormone binding variant that is found only in mammals. TRα2 shares an unusual antisense coding overlap with mRNA for Rev-erbα (NR1D1), another nuclear receptor protein. In this study we examine the structure and expression of these genes in the gray short-tailed opossum, Monodelphis domestica, in comparison with that of eutherian mammals and three other marsupial species, Didelphis virginiana, Potorous tridactylus and Macropus eugenii, in order to understand the evolution and regulatory role of this antisense overlap. Results The sequence, expression and genomic organization of mRNAs encoding TRα1 and Rev-erbα are very similar in the opossum and eutherian mammals. However, the sequence corresponding to the TRα2 coding region appears truncated by almost 100 amino acids. While expression of TRα1 and Rev-erbα was readily detected in all tissues of M. domestica ages 0 days to 18 weeks, TRα2 mRNA was not detected in any tissue or stage examined. These results contrast with the widespread and abundant expression of TRα2 in rodents and other eutherian mammals. To examine requirements for alternative splicing of TRα mRNAs, a series of chimeric minigenes was constructed. Results show that the opossum TRα2-specific 5' splice site sequence is fully competent for splicing but the sequence homologous to the TRα2 3' splice site is not, even though the marsupial sequences are remarkably similar to core splice site elements in rat. Conclusions Our results strongly suggest that the variant nuclear receptor isoform, TRα2, is not expressed in marsupials and that the antisense overlap between TRα and Rev-erbα thus is unique to eutherian mammals. Further investigation of the TRα and Rev-erbα genes in marsupial and eutherian species promises to yield additional insight into the

  17. Debilitation and mortality associated with besnoitiosis in four Virginia opossums (Didelphis virginiana).

    Science.gov (United States)

    Ellis, Angela E; Mackey, Elizabeth; Moore, Philip A; Divers, Stephen J; Hensel, Patrick; Carmichael, K Paige; Accola, Peter; Brown, Justin; Gottdenker, Nicole; Keel, M Kevin; Shock, Barbara C; Yabsley, Michael J

    2012-06-01

    Besnoitia spp. are coccidian parasites that infect a variety of wild and domestic mammals as well as some reptiles. Although infection with Besnoitia is common in Virginia opossums (Didelphis virginiana), clinical signs or death due to Besnoitia is rare. This manuscript describes four Virginia opossums that had severe clinical disease and inflammation associated with besnoitiosis. Clinical signs included trembling, incoordination, circling, blindness, poor body condition, and sudden death. Gross lesions included parasitic cysts in eyes, skin, and visceral organs. Histologically, cysts were often degenerate and associated with mild to marked inflammation, and amyloidosis was noted in one animal. Polymerase chain reaction and sequencing confirmed Besnoitia darlingi in three of the four opossums.

  18. Experimental transmission of Sarcocystis speeri Dubey and Lindsay, 1999 from the South American opossum (Didelphis albiventris) to the North American opossum (Didelphis virginiana).

    Science.gov (United States)

    Dubey, J P; Speer, C A; Bowman, D D; Horton, K M; Venturini, C; Venturini, L

    2000-06-01

    Sarcocystis speeri Dubey and Lindsay, 1999 from the South American opossum Didelphis albiventris was successfully transmitted to the North American opossum Didelphis virginiana. Sporocysts from a naturally infected D. albiventris from Argentina were fed to 2 gamma-interferon knockout (KO) mice. The mice were killed 64 and 71 days after sporocyst feeding (DAF). Muscles containing sarcocysts from the KO mouse killed 71 DAF were fed to a captive D. virginiana; this opossum shed sporocysts 11 days after ingesting sarcocysts. Sporocysts from D. virginiana were fed to 9 KO mice and 4 budgerigars (Melopsittacus undulatus). Schizonts, sarcocysts, or both of S. speeri were found in tissues of all 7 KO mice killed 29-85 DAF; 2 mice died 39 and 48 DAF were not necropsied. Sarcocystis stages were not found in tissues of the 4 budgerigars fed S. speeri sporocysts and killed 35 DAE These results indicate that S. speeri is distinct from Sarcocystis falcatula and Sarcocystis neurona, and that S. speeri is present in both D. albiventris and D. virginiana.

  19. Besnoitia darlingi infection in a Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    Shaw, Shannon; Grasperge, Britton; Nevarez, Javier; Reed, Scott; Long, Lauren; Rademacher, Nathalie; Sánchez-Migallón Guzmán, David

    2009-03-01

    This is a case report of natural infection with Besnoitia darlingi in a Virginia opossum (Didelphis virginiana) in Louisiana. Clinical pathologic data included a severe nonregenerative anemia, inflammatory leukogram, increased hepatocellular leakage enzymes, renal azotemia, hyperkalemia, hypoglycemia, hypoalbuminemia, and proteinuria. Tissue cysts containing bradyzoites were found in the majority of organs, especially the skin, mucous membranes, kidneys, adrenals, lungs, and heart. Images of the bradyzoites obtained by transmission electron microscopy were consistent with the previously described ultrastructure of Besnoitia darlingi. This opossum also suffered from an open phalangeal fracture and concurrent gastrointestinal parasites. Histopathologic findings included a glomerulonephritis and hepatic necrosis.

  20. oPOSSUM-3: advanced analysis of regulatory motif over-representation across genes or ChIP-Seq datasets.

    Science.gov (United States)

    Kwon, Andrew T; Arenillas, David J; Worsley Hunt, Rebecca; Wasserman, Wyeth W

    2012-09-01

    oPOSSUM-3 is a web-accessible software system for identification of over-represented transcription factor binding sites (TFBS) and TFBS families in either DNA sequences of co-expressed genes or sequences generated from high-throughput methods, such as ChIP-Seq. Validation of the system with known sets of co-regulated genes and published ChIP-Seq data demonstrates the capacity for oPOSSUM-3 to identify mediating transcription factors (TF) for co-regulated genes or co-recovered sequences. oPOSSUM-3 is available at http://opossum.cisreg.ca.

  1. Normal conjunctival flora in the North American opossum (Didelphis virginiana) and raccoon (Procyon lotor).

    Science.gov (United States)

    Pinard, Chantale L; Brightman, Alan H; Yeary, Teresa J; Everson, Troy D; Cox, Linda K; Chengappa, M M; Davidson, Harriet J

    2002-10-01

    We documented the normal conjunctival bacterial flora from 17 opossums (Didelphis virginiana) and 10 raccoons (Procyon lotor) trapped in Manhattan, Kansas (USA) from November 1999 to January 2000. Both raccoons and opossums were free of apparent ocular disease. The inferior conjunctival sacs of each animal were swabbed for aerobic bacterial and Mycoplasma culture and polymerase chain reaction (PCR) for Mycoplasma and Chlamydia detection. All conjunctival samples were positive for one or more species of aerobic bacteria. The most common isolate from opossums was Staphylococcus spp. Other isolates included Streptococcus spp., Bacillus spp., Corynebacterium spp., and Enterococcus faecalis. The most common isolates in raccoons was Bacillus spp. Other isolates included Streptococcus spp., Staphylococcus spp., non-hemolytic Escherichia coli, and Enterococcus faecalis. Mycoplasma culture was negative in samples from opossums and raccoons. Evidence of Mycoplasma and Chlamydia presence was detected by PCR.

  2. The anatomy of a (potential) disaster: Volcanoes, behavior, and population viability of the short-tailed albatross (Phoebastria albatrus)

    Science.gov (United States)

    Finkelstein, M.E.; Wolf, S.; Goldman, M.; Doak, D.F.; Sievert, P.R.; Balogh, G.; Hasegawa, H.

    2010-01-01

    Catastrophic events, either from natural (e.g., hurricane) or human-induced (e.g., forest clear-cut) processes, are a well-known threat to wild populations. However, our lack of knowledge about population-level effects of catastrophic events has inhibited the careful examination of how catastrophes affect population growth and persistence. For the critically endangered short-tailed albatross (Phoebastria albatrus), episodic volcanic eruptions are considered a serious catastrophic threat since approximately 80% of the global population of ???2500 birds (in 2006) currently breeds on an active volcano, Torishima Island. We evaluated how short-tailed albatross population persistence is affected by the catastrophic threat of a volcanic eruption relative to chronic threats. We also provide an example for overcoming the seemingly overwhelming problems created by modelling the population dynamics of a species with limited demographic data by incorporating uncertainty in our analysis. As such, we constructed a stochastic age-based matrix model that incorporated both catastrophic mortality due to volcanic eruptions and chronic mortality from several potential sources (e.g., contaminant exposure, fisheries bycatch) to determine the relative effects of these two types of threats on short-tailed albatross population growth and persistence. Modest increases (1%) in chronic (annual) mortality had a 2.5-fold greater effect on predicted short-tailed albatross stochastic population growth rate (lambda) than did the occurrence of periodic volcanic eruptions that follow historic eruption frequencies (annual probability of eruption 2.2%). Our work demonstrates that periodic catastrophic volcanic eruptions, despite their dramatic nature, are less likely to affect the population viability and recovery of short-tailed albatross than low-level chronic mortality. ?? 2009 Elsevier Ltd.

  3. Sarcocystis neurona and Neospora caninum in Brazilian opossums (Didelphis spp.): Molecular investigation and in vitro isolation of Sarcocystis spp.

    Science.gov (United States)

    Gondim, Leane S Q; Jesus, Rogério F; Ribeiro-Andrade, Müller; Silva, Jean C R; Siqueira, Daniel B; Marvulo, Maria F V; Aléssio, Felipe M; Mauffrey, Jean-François; Julião, Fred S; Savani, Elisa San Martin Mouriz; Soares, Rodrigo M; Gondim, Luís F P

    2017-08-30

    Sarcocystis neurona and Neospora spp. are protozoan parasites that induce neurological diseases in horses and other animal species. Opossums (Didelphis albiventris and Didelphis virginiana) are definitive hosts of S. neurona, which is the major cause of equine protozoal myeloencephalitis (EPM). Neospora caninum causes abortion in cattle and infects a wide range of animal species, while N. hughesi is known to induce neurologic disease in equids. The aims of this study were to investigate S. neurona and N. caninum in tissues from opossums in the northeastern Brazil, and to isolate Brazilian strains of Sarcocystis spp. from wild opossums for comparison with previously isolated strains. Carcasses of 39 opossums from Bahia state were available for molecular identification of Sarcocystis spp. and N. caninum in their tissues, and for sporocyst detection by intestinal scraping. In addition, Sarcocystis-like sporocysts from nine additional opossums, obtained in São Paulo state, were tested. Sarcocystis DNA was found in 16 (41%) of the 39 opossums' carcasses; N. caninum DNA was detected in tissues from three opossums. The sporocysts from the nine additional opossums from São Paulo state were tested by bioassay and induced infection in nine budgerigars, but in none of the gamma-interferon knockout mice. In vitro isolation was successful using tissues from all nine budgerigars. The isolated strains were maintained in CV-1 and Vero cells. Three of nine isolates presented contamination in cell culture and were discarded. Analysis of six isolates based on five loci showed that these parasites were genetically different from each other and also distinct from S. neurona, S. falcatula, S. lindsayi, and S. speeri. In conclusion, opossums in the studied regions were infected with N. caninum and Sarcocystis spp. and represent a potential source of infection to other animals. This is the first report of N. caninum infection in tissues from black-eared opossum (D. aurita or D

  4. A retrospective study of 11 cases of lungworm (Didelphostrongylus hayesi) infection in opossums (Didelphis virginiana).

    Science.gov (United States)

    Lamberski, Nadine; Reader, J Rachel; Cook, Lizette F; Johnson, Eileen M; Baker, David G; Lowenstine, Linda J

    2002-06-01

    A juvenile, female North American opossum (Didelphis virginiana) died of verminous pneumonia caused by Didelphostrongylus haysei despite aggressive treatment with oral fenbendazole, corticosteroids, and antibiotics. This prompted a retrospective study of lungworm infection in opossums, during which 19 additional necropsy reports from opossums were reviewed. Including the subject of this report, a total of 11 (55%) of these cases included a diagnosis of lungworm infection. This diagnosis was considered to have contributed to death in eight out of the 11 cases (73%). Histologically, 10 of the 11 (91%) opossums had granulomatous bronchopneumonia with small to moderate numbers of adult nematodes in the airways and parenchyma. Four of the 11 (36%) opossums had free larvae within the parenchyma or terminal airways. Inflammation was usually associated with larvae, degenerating parasites, and nonintact adult nematodes. Superimposed bacterial pneumonia was evident in three animals, and sections of lung examined from all the opossums were characterized by moderate to severe smooth-muscle hyperplasia in airways, including terminal respiratory bronchioles and alveolar ducts. Nine animals had prominent medial smooth-muscle hyperplasia in small- and medium-sized arterioles. Lesions in other organs, particularly in liver, heart, and gastrointestinal tract, were frequently identified. Three animals had concomitant septicemia or bacterial bronchopneumonia (or both), which contributed to the cause of death. Seven animals had gastric nematodosis (Physaloptera sp.), although three of them had been treated with a 14-day course of fenbendazole.

  5. Evaluation of the shedding of Sarcocystis falcatula sporocysts in experimentally infected Virginia opossums (Didelphis virginiana).

    Science.gov (United States)

    Porter, R A; Ginn, P E; Dame, J B; Greiner, E C

    2001-02-26

    Five Virginia opossums (Didelphis virginiana) were fed muscles of brown-headed cowbirds (Molothrus ater) containing sarcocysts of Sarcocystis falcatula. Shedding of sporocysts was confirmed in all five opossums by fecal flotation. Counts were conducted daily for 2 weeks and then biweekly until the animals were euthanized and necropsied. The average prepatent period was 9.8 (7-16) days. The number of sporocysts shed varied greatly between the opossums with maximum mean shedding occurring at 71.6 (26-112) days post-infection (DPI). Average sporocyst production was 1480 sporocysts/gram of feces (SPG). Maximum output was 37,000 SPG. Average fecal yield in captivity was 17.5g of feces/day. Opossums shed 25,900 sporocysts/day (average) and a maximum of 647,500 sporocysts/day. All opossums shed sporocysts until time of euthanasia (46-200 DPI). Histologically, numerous sporocysts were present in the lamina propria at necropsy, primarily in the proximal half of the small intestine. Sporocysts were generally in clusters within the lamina propria of the luminal two-thirds of the villi. Sporocysts were found less frequently in the epithelium. No evidence of ongoing gametogony or other development was evident.

  6. Molecular discrimination of pouched four-eyed opossums from the Mamirauá Reserve in the Brazilian Amazon

    OpenAIRE

    Nunes,Cláudia; Ayres,Jose Marcio; Sampaio,Iracilda; Schneider,Horacio

    2006-01-01

    Previous cytochrome B (CytB) mtDNA studies have suggested four species for the opossum genus Philander (four-eyed opossums), three (P. mcilhennyi, P. andersoni and P. opossum) from the Amazon and one (P. frenata) from the Brazilian Atlantic forest. During a faunal survey nine specimens of Philander sp. and four of Didelphis marsupialis were collected in the Mamirauá Sustainable Reserve, Amazonas State, Brazil. Preliminary analyses based on morphology and geographical distributions were not co...

  7. Site selection by intestinal helminths of the Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    Ellis, R D; Pung, O J; Richardson, D J

    1999-02-01

    Digestive tract helminths of the Virginia opossum (Didelphis virginiana) were examined for site specificity and interspecific interactions. Thirty opossums were live-trapped at 2 localities in Georgia, killed, and their digestive tracts removed and divided into the following sections; esophagus, stomach, small intestine (20 equal sections), cecum, and large intestine (5 equal sections). Helminths present in each section were identified and counted. Three trematode, 1 cestode, 2 acanthocephala, and 6 nematode species were found. Two parasites (the acanthocephalan Centrorhynchus spinosus and the nematode Viannaia hamata) are new state records for Georgia and this is the first report of C. spinosus from an opossum. There was considerable overlap between the spatial distributions of many of the helminth species found in the small intestine though most species had different modal locations. Helminth species locations were unaffected by host sex or trapping locality. There was no evidence that the presence, absence, or intensity of any helminth species affected the location or intensity of other helminth species in the digestive tract.

  8. Experimental Bacterial Endocarditis in the Opossum (Didelphis virginiana)

    Science.gov (United States)

    Sherwood, B. F.; Rowlands, D. T.; Vakilzadeh, J.; LeMay, J. C.

    1971-01-01

    It was possible to induce bacterial endocarditis in opossums with single intravenous injections of Streptococcus viridans or Staphylococcus aureus. Fiftyeight percent of those animals given Streptococcus viridans developed bacterial endocarditis in which most of the lesions were on the left side of the heart. The experimentally induced streptococcal disease was similar to that which may occur spontaneously in opossums, both with respect to the distribution and structure of the vegetations. Single injections of Staphylococcus aureus resulted in endocarditis in 100% of the test animals. These lesions differed from those due to streptococci by having a relatively high frequency of right- as well as left-sided valvular disease and by being somewhat smaller than those due to streptococci.Endocarditis could not be successfully induced with injection of three different fungi. PMID:5133514

  9. ABCB4 mediates diet-induced hypercholesterolemia in laboratory opossums.

    Science.gov (United States)

    Chan, Jeannie; Mahaney, Michael C; Kushwaha, Rampratap S; VandeBerg, Jane F; VandeBerg, John L

    2010-10-01

    High-responding opossums are susceptible to developing hypercholesterolemia on a high-cholesterol diet, but low-responding opossums are resistant. The observation of low biliary cholesterol and low biliary phospholipids in high responders suggested that the ABCB4 gene affects response to dietary cholesterol. Two missense mutations (Arg29Gly and Ile235Leu) were found in the ABCB4 gene of high responders. High responders (ATHH strain) were bred with low responders (ATHE or ATHL strain) to produce F1 and F2 progeny in two different genetic crosses (KUSH6 and JCX) to determine the effect of ABCB4 allelic variants on plasma cholesterol concentrations after a dietary challenge. Pedigree-based genetic association analyses consistently implicated a variant in ABCB4 or a closely linked locus as a major, but not the sole, genetic contributor to variation in the plasma cholesterol response to dietary cholesterol. High responders, but not low responders, developed liver injury as indicated by elevated plasma biomarkers of liver function, probably reflecting damage to the canalicular membrane by bile salts because of impaired phospholipid secretion. Our results implicate ABCB4 as a major determinant of diet-induced hypercholesterolemia in high-responding opossums and suggest that other genes interact with ABCB4 to regulate lipemic response to dietary cholesterol.

  10. Experimental Aerosol Inoculation and Investigation of Potential Lateral Transmission of Mycobacterium bovis in Virginia Opossum (Didelphis virginiana)

    OpenAIRE

    Fenton, Karla A.; Fitzgerald, Scott D.; Bolin, Steve; Kaneene, John; Sikarskie, James; Greenwald, Rena; Lyashchenko, Konstantin

    2012-01-01

    An endemic focus of Mycobacterium bovis (M. bovis) infection in the state of Michigan has contributed to a regional persistence in the animal population. The objective of this study was to determine if Virginia opossums (Didelphis virginiana) contribute to disease persistence by experimentally assessing intraspecies lateral transmission. One wild caught pregnant female opossum bearing 11 joeys (young opossum) and one age-matched joey were obtained for the study. Four joeys were aerosol inocul...

  11. FINE STRUCTURE OF THE NEUROHYPOPHYSIS OF THE OPOSSUM (DIDELPHIS VIRGINIANA)

    Science.gov (United States)

    Roth, Lawrence M.; Luse, Sarah A.

    1964-01-01

    The neurohypophysis of the opossum (Didelphis virginiana) was studied by electron microscopy in order to amplify Bodian's classic light microscopic observations in which he demonstrated a definite lobular pattern. The lobule of the opossum neurohypophysis is divided into three regions: a hilar, a palisade, and a septal zone. The hilar portion contains bundles of nerve fibers, the extensions of the hypothalamo-hypophyseal tract containing neurofilaments but few neurosecretory granules. In the opossum, pituicytes have a densely fibrillar cytoplasm. Herring bodies are prominent in the hilar region. They are large bodies packed with neurosecretory granules that have been described as end bulb formations of axons. From the hilar region, axons fan out into a palisade zone where the nerve terminals packed with neurosecretory granules, mitochondria, and microvesicles abut upon basement membranes. The neurosecretory granules are similar to those present in the neurohypophysis of other mammals, except for an occasional huge granule of distinctive type. Material morphologically and histochemically resembling glycogen occurs as scattered particles and as aggregates within nerve fibers. The septal zone, containing collagen, fibroblasts, and numerous small capillaries, is separated from the adjacent glandular tissue by a basement membrane. PMID:14128048

  12. Molecular discrimination of pouched four-eyed opossums from the Mamirauá Reserve in the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Cláudia Nunes

    2006-01-01

    Full Text Available Previous cytochrome B (CytB mtDNA studies have suggested four species for the opossum genus Philander (four-eyed opossums, three (P. mcilhennyi, P. andersoni and P. opossum from the Amazon and one (P. frenata from the Brazilian Atlantic forest. During a faunal survey nine specimens of Philander sp. and four of Didelphis marsupialis were collected in the Mamirauá Sustainable Reserve, Amazonas State, Brazil. Preliminary analyses based on morphology and geographical distributions were not conclusive, suggesting that Philander specimens could belong to either P. andersoni or P. opossum. In order to elucidate the relationship of this taxon to the remaining Amazonian taxa, seven Philander and two Didelphis specimens animals were sequenced for the cytB mtDNA gene and compared to other previously studied taxa. The maximum likelihood (ML, neighbor-Joining (NJ and maximum parsimony (MP consensus bootstrap trees depicted six groups: Didelphis., P. frenata, P andersoni, P. mcilhennyi, P.o. opossum and Philander sp. and Philander canus in a common assemblage supported by significant bootstrap values, suggesting that the Philander sp. from Mamiraua in fact belongs to the species Philander canus.

  13. Pythons in Burma: Short-tailed python (Reptilia: Squamata)

    Science.gov (United States)

    Zug, George R.; Gotte, Steve W.; Jacobs, Jeremy F.

    2011-01-01

    Short-tailed pythons, Python curtus species group, occur predominantly in the Malayan Peninsula, Sumatra, and Borneo. The discovery of an adult female in Mon State, Myanmar, led to a review of the distribution of all group members (spot-mapping of all localities of confirmed occurrence) and an examination of morphological variation in P. brongersmai. The resulting maps demonstrate a limited occurrence of these pythons within peninsular Malaya, Sumatra, and Borneo with broad absences in these regions. Our small samples limit the recognition of regional differentiation in the morphology of P. brongersmai populations; however, the presence of unique traits in the Myanmar python and its strong allopatry indicate that it is a unique genetic lineage, and it is described as Python kyaiktiyo new species.

  14. Radiation lethality in the opossum

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, N.; Bushong, S.C.; North, L.B.; Thornby, J.

    1976-12-01

    Groups of male opossum (Didelphis virginiana) at 6 months of age were exposed to 350, 500, 550, 600, 650, 700, and 750 rad of whole-body /sup 60/Co radiation at a midline dose rate of 125 rad/min. The 30-day LD/sub 50/ was 511 rad with 95% confidence limits of 454 to 576 rad. The overall mean survival time was 17.9 days and the highest incidence of death occurred on the 16th day.

  15. Radiation lethality in the opossum

    International Nuclear Information System (INIS)

    Prasad, N.; Bushong, S.C.; North, L.B.; Thornby, J.

    1976-01-01

    Groups of male opossum (Didelphis virginiana) at 6 months of age were exposed to 350, 500, 550, 600, 650, 700, and 750 rad of whole-body 60 Co radiation at a midline dose rate of 125 rad/min. The 30-day LD 50 was 511 rad with 95% confidence limits of 454 to 576 rad. The overall mean survival time was 17.9 days and the highest incidence of death occurred on the 16th day

  16. Endoparásitos de micromamíferos del noroeste de Perú. 1: helmintos de marsupiales

    Directory of Open Access Journals (Sweden)

    Manuel Tantaleán

    2011-05-01

    Full Text Available En este trabajo, informamos los resultados del análisis parasitológico realizado a 40 individuos marsupiales de las especies Caluromys lanatus, Didelphis marsupialis, Marmosops noctivagus, Metachirus nudicaudatus, Marmosa (Micoureus regina, Monodelphis adusta, Philander andersoni y Philander opossum procedentes del departamento de Loreto, Perú. Se determinaron en total 11 especies de helmintos parásitos: Nematoda: Aspidodera sp., Cruzia tentaculata, Physaloptera mirandai, Physaloptera sp., Pterygodermatites sp., Trichuris sp., Turgida turgida, y Viannaia sp.; Trematoda: Podospathalium pedatum; Acanthocephala: Giganthorhynchus ortizi; y Pentastomida: ninfa. Los parásitos Trichuris sp., Pterygodematities sp., Turgida turgida, Viannaia sp. y Podospathalium pedatum son nuevos registros para el Perú. De igual manera, se registran por primera vez las siguientes asociaciones parásitos-huéspedes: Pterygodermatites sp.-Marmosa regina, Viannaia sp.- Marmosops noctivagus, Trichuris sp.-Marmosops cf. noctivagus, Podospathalium pedatum-Monodelphis adusta, Giganthorhynchus ortizi-Marmosops cf. noctivagus, y ninfas de pentastómidos-Marmosa regina y Metachirus nudicaudatus.

  17. Intrahepatic growth and maturation of Gnathostoma turgidum in the natural definitive opossum host, Didelphis virginiana.

    Science.gov (United States)

    Díaz-Camacho, Sylvia Páz; Delgado-Vargas, Francisco; Willms, Kaethe; de la Cruz-Otero, María del Carmen; Guadalupe Rendón-Maldonado, José; Robert, Lilia; Antuna, Silvia; Nawa, Yukifumi

    2010-09-01

    Gnathostoma turgidum is a gastric nematode parasite of opossums found in the Americas. We recently found that G. turgidum juveniles appear in the liver of the opossums where they become mature adults and almost synchronously move to the stomach during certain months of the year, suggesting the importance of the liver for the growth and maturation of this species in the final hosts. In this study we attempted to detect G. turgidum larvae in the liver of opossums, Didelphis virginiana that are the natural final hosts. The results show that tiny (<3mm in length) third stage larvae (L3) appeared in the liver of opossums around November and December. Also in the liver, we found large L3 of up to about 10mm in length together with juveniles and mature adults from February to March. In spite of their length, large L3 have 4 rows of hooklets, and their gonads remained undeveloped. Morphological features of the small and large L3 of G. turgidum are described including scanning electron microscope images. The seasonal switching of the several growth stages of G. turgidum from small L3 to adult worms in the liver and eventual migration to the stomach in opossums suggests the unique feature of G. turgidum utilizing the liver as the maturation site.

  18. ABCB4 mediates diet-induced hypercholesterolemia in laboratory opossums[S

    Science.gov (United States)

    Chan, Jeannie; Mahaney, Michael C.; Kushwaha, Rampratap S.; VandeBerg, Jane F.; VandeBerg, John L.

    2010-01-01

    High-responding opossums are susceptible to developing hypercholesterolemia on a high-cholesterol diet, but low-responding opossums are resistant. The observation of low biliary cholesterol and low biliary phospholipids in high responders suggested that the ABCB4 gene affects response to dietary cholesterol. Two missense mutations (Arg29Gly and Ile235Leu) were found in the ABCB4 gene of high responders. High responders (ATHH strain) were bred with low responders (ATHE or ATHL strain) to produce F1 and F2 progeny in two different genetic crosses (KUSH6 and JCX) to determine the effect of ABCB4 allelic variants on plasma cholesterol concentrations after a dietary challenge. Pedigree-based genetic association analyses consistently implicated a variant in ABCB4 or a closely linked locus as a major, but not the sole, genetic contributor to variation in the plasma cholesterol response to dietary cholesterol. High responders, but not low responders, developed liver injury as indicated by elevated plasma biomarkers of liver function, probably reflecting damage to the canalicular membrane by bile salts because of impaired phospholipid secretion. Our results implicate ABCB4 as a major determinant of diet-induced hypercholesterolemia in high-responding opossums and suggest that other genes interact with ABCB4 to regulate lipemic response to dietary cholesterol. PMID:20488799

  19. Spontaneous neoplasms in captive Virginia opossums ( Didelphis virginiana): a retrospective case series (1989-2014) and review of the literature.

    Science.gov (United States)

    Pope, Jenny P; Donnell, Robert L

    2017-05-01

    This retrospective project summarizes the types of neoplasms identified in Virginia opossums ( Didelphis virginiana) presented to the University of Tennessee, College of Veterinary Medicine (UTCVM) postmortem service in 1989-2014 and serves as a review of the literature. Of the 85 Virginia opossums identified from the UTCVM case database, there were 17 diagnoses of neoplasia from 12 cases (14%). These cases included 8 females, 2 males, and 2 neutered males. All opossums with known ages (11 of 12) were >2 y old. Pulmonary tumors, specifically minimally invasive or lepidic-predominant adenocarcinomas, were the most common diagnosis and accounted for 53% (9 of 17) of the neoplasms. Additional tumors included acute myeloid leukemia with eosinophil maturation, hepatic hemangiosarcoma, sarcoma (unknown origin), squamous cell carcinoma, disseminated mast cell tumor, trichoblastoma, thyroid adenoma, and an osteoma. These findings serve as a reference for the types of spontaneous neoplasms in Virginia opossums; based on these findings, neoplasia should be considered as a differential in mature captive Virginia opossums.

  20. Isolation of 21 polymorphic microsatellite markers for the Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    Fike, Jennifer A; Beasley, James C; Rhodes, Olin E

    2009-07-01

    Twenty-one polymorphic microsatellite markers were developed for the Virginia opossum (Didelphis virginiana). The number of alleles ranged from two to 13 and observed heterozygosities ranged from 0.464 to 0.964. Significant heterozygote deficiencies were observed at three loci and null alleles were detected at five loci. Evidence for gametic disequilibrium was observed between three sets of paired loci after a sequential Bonferroni correction was applied. These markers will enable us to investigate the mating tactics, movement behaviour and social structure of Virginia opossum populations inhabiting fragmented agricultural landscapes. © 2009 Blackwell Publishing Ltd.

  1. Observations on besnoitiosis in Virginia opossum (Didelphis virginiana) from Michigan, USA.

    Science.gov (United States)

    El Sheikha, Hany M; Hussein, Hussein S; Monib, Mohammad el-Salahy M; Mansfield, Linda S

    2007-04-01

    Besnoitia tissue cysts were found in five naturally-infected adult opossums (Didelphis virginiana) from Michigan. Details of the microscopy, histopathology, ultra-structure, and genetic features of the cysts were studied to identify their species-specific traits. The materials were differentiated phenotypically from cysts of other Besnoitia spp. by difference in size, pattern of tissue distribution, morphology of pellicle and nucleus, number of micronemes and rhoptries, amount of lipids and amylopectin, and presence of enigmatic bodies. Morphometric variations identified the tissue cysts and the pathologic changes in opossums host to be due to B. darlingi. The data were proved by phylogenetic analysis based on DNA sequences of the first internal transcribed spacer of nuclear rDNA. Cluster analysis showed that B. darlingi was distinct from all other Besnoitia spp. as two distinct phylogenetic clades: I- included Besnoitia spp. described from opossum (B. darlingi), sheep (B. jellisoni), rodent (B. akadoni) and rabbit (B. oryctofelisi) and clade II- encompassed parasites described from cattle (B. besnoiti), equids (B. bennetti) and reindeer (B. tarandi). The genetic attributed particular to the genus Besnoitia complemented the morphologica features and lead to accurate delimitation of Besnoitia species.

  2. The detection of hemorrhagic proteins in snake venoms using monoclonal antibodies against Virginia opossum (Didelphis virginiana) serum.

    Science.gov (United States)

    Sánchez, E E; García, C; Pérez, J C; De La Zerda, S J

    1998-10-01

    Most snakes and a few warm-blooded animals have a resistance to snake venoms because of naturally occurring antihemorrhagins found in their sera. The antihemorrhagins in serum of Virginia opossum (Didelphis virginiana) neutralize hemorrhagic activity by binding to hemorrhagins in snake venoms. The binding characteristic of antihemorrhagins in D. virginiana serum was used to develop a five-step western blot. The detection of hemorrhagic proteins were measured indirectly with antihemorrhagins in Virginia opossum serum and with DV-2LD#2, a monoclonal antibody specific for Virginia opossum antihemorrhagins. Snake venoms were separated by native-PAGE, transferred to a Millipore Immobilon-P membrane and then incubated with crude Virginia opossum serum. The hemorrhagins in snake venom bind to antihemorrhagins in Virginia opossum serum which react with DV-2LD#2 a monoclonal antibody that is specific for Virginia opossum antihemorrhagins. DV-2LD#2 monoclonal antibody inhibits antihemorrhagic activity in Virginia opossum serum when mixed in equal amounts. The inhibition of antihemorrhagins by DV-2LD#2 monoclonal antibody suggests specificity. DV-2LD#2 monoclonal antibody does not recognize antihemorrhagins in gray woodrat (Neotoma micropus) serum. The five-step western blot reveals two well-defined bands which represent hemorrhagins found in Western diamondback rattlesnake (Crotalus atrox) venom. Venoms from 15 different snake species were examined to determine the usefulness of the five-step western blot. Other hemorrhagic venoms (Great Basin rattlesnake (C. viridis lutosus), Prairie rattlesnake (C. viridis viridis), Tancitaran dusky rattlesnake (C. pusillus), Northern Mojave rattlesnake (C. scutulatus scutulatus type B) and Northern Pacific rattlesnake (C. v. oreganus)) had one single band in the five-step western blot. DV-2LD#2 did not bind to the non-hemorrhagic venoms and reacted with 50% of the hemorrhagic venoms used in this study. The monoclonal antibody, CAH

  3. SINEs, evolution and genome structure in the opossum.

    Science.gov (United States)

    Gu, Wanjun; Ray, David A; Walker, Jerilyn A; Barnes, Erin W; Gentles, Andrew J; Samollow, Paul B; Jurka, Jerzy; Batzer, Mark A; Pollock, David D

    2007-07-01

    Short INterspersed Elements (SINEs) are non-autonomous retrotransposons, usually between 100 and 500 base pairs (bp) in length, which are ubiquitous components of eukaryotic genomes. Their activity, distribution, and evolution can be highly informative on genomic structure and evolutionary processes. To determine recent activity, we amplified more than one hundred SINE1 loci in a panel of 43 M. domestica individuals derived from five diverse geographic locations. The SINE1 family has expanded recently enough that many loci were polymorphic, and the SINE1 insertion-based genetic distances among populations reflected geographic distance. Genome-wide comparisons of SINE1 densities and GC content revealed that high SINE1 density is associated with high GC content in a few long and many short spans. Young SINE1s, whether fixed or polymorphic, showed an unbiased GC content preference for insertion, indicating that the GC preference accumulates over long time periods, possibly in periodic bursts. SINE1 evolution is thus broadly similar to human Alu evolution, although it has an independent origin. High GC content adjacent to SINE1s is strongly correlated with bias towards higher AT to GC substitutions and lower GC to AT substitutions. This is consistent with biased gene conversion, and also indicates that like chickens, but unlike eutherian mammals, GC content heterogeneity (isochore structure) is reinforced by substitution processes in the M. domestica genome. Nevertheless, both high and low GC content regions are apparently headed towards lower GC content equilibria, possibly due to a relative shift to lower recombination rates in the recent Monodelphis ancestral lineage. Like eutherians, metatherian (marsupial) mammals have evolved high CpG substitution rates, but this is apparently a convergence in process rather than a shared ancestral state.

  4. Helminths of the Virginia opossum Didelphis virginiana (Mammalia: Didelphidae) in Mexico.

    Science.gov (United States)

    Monet-Mendoza, Anne; Osorio-Sarabia, David; García-Prieto, Luis

    2005-02-01

    The goal of this study was to provide further information about helminth parasites of Virginia opossum Didelphis virginiana Kerr, 1792 from Mexico. During routine faunal investigations between 1958 and 2001, 101 opossum were necropsied. Nineteen taxa of helminths were collected, representing 13 genera from hosts in 27 localities from Mexico. There are 58 new locality records, with 6 species recorded in Mexico for the first time: Brachylaima virginiana Dickerson, 1930; Cruzia americana Mapleston, 1930; Didelphonema longispiculata (Hill, 1939); Didelphostrongylus hayesi Prestwood, 1976; Viannaia didelphis Travassos, 1914; and Viannaia viannai Travassos, 1914. This increases the number of helminth taxa previously known for this host in Mexico to 28.

  5. Isolation and characterization of a marsupial DNA photolyase

    Energy Technology Data Exchange (ETDEWEB)

    Sabourin, C.L.K.; Ley, R.D.

    1988-05-01

    Post UV-B (280-320 nm) exposure to UV-A (320-400 nm) reverses pyrimidine dimers in the epidermal DNA of the South American opossum Monodelphis domestica. To demonstrate that the observed photorepair is mediated by an enzyme, we have isolated a DNA photolyase from the opossum. DNA photolyase from liver was purified 3000-fold by ammonium sulfate fractionation and phenylsepharose, hydroxylapatite, DEAE-cellulose and DNA-cellulose column chromatography. Heat denaturation completely eliminated the photoreactivating activity. The enzyme was active in the pH range of 5.5 to 8.5 with a pH optimum of 7.5. The enzyme has an apparent molecular weight of 32 000 under nondenaturing conditions. The activity of the enzyme was not affected by sodium chloride up to 250 mM. The action spectrum for the purified DNA photolyase showed activity in the range of 325-475 nm with peak activity at 375 nm.

  6. Spontaneous cure after natural infection with Gnathostoma turgidum (Nematoda) in Virginia opossums (Didelphis virginiana).

    Science.gov (United States)

    Torres-Montoya, Hilario; Galaviz-Renteria, Xochilth; Castillo-Ureta, Hipólito; Lopez-Moreno, Hector; Nawa, Yukifumi; Bojorquez-Contreras, Angel; Sanchez-Gonzalez, Sergio; Díaz-Camacho, Sylvia; Rocha-Tirado, Rodrigo; Rendon-Maldonado, Jose

    2014-04-01

    Seasonality of the nematode Gnathostoma turgidum in Virginia opossums (Didelphis virginiana) in the wild has been reported; however, the mechanisms involved in deworming are unknown. We monitored the parasitologic and biologic changes in four Virginia opossums naturally infected with G. turgidum by coproparasitologic examination and abdominal ultrasonography. Eggs became detectable in the feces of opossums in May, peaked in July and August, and suddenly decreased in October. Adults of G. turgidum were expelled in the feces mainly in September. Ultrasonography of the liver showed slight damage during May. Lesions in the stomach appeared in April and persisted until September. The abnormalities of the liver and stomach were resolved in November. These data suggest that G. turgidum is likely expelled as a result of host immunologic mechanisms, although termination of a natural life span cannot be definitively excluded.

  7. Experimental induction of equine protozoal myeloencephalitis in horses using Sarcocystis sp. sporocysts from the opossum (Didelphis virginiana).

    Science.gov (United States)

    Fenger, C K; Granstrom, D E; Gajadhar, A A; Williams, N M; McCrillis, S A; Stamper, S; Langemeier, J L; Dubey, J P

    1997-02-01

    Sarcocystis sp. sporocysts isolated from eight feral opossums (Didelphis virginiana) were pooled and fed to 18 commercially reared budgerigars (Melopsittacus undulatus), 14 wild-caught sparrows (Passer domesticus), one wild-caught slate-colored Junco (Junco hyemalis) and five weanling horses (Equus caballus). All budgerigars died within 5 weeks post inoculation (wpi). Histologic examination revealed meronts within the pulmonary epithelia and typical Sarcocystis falcatula sarcocysts developing in the leg muscles. Sparrows were euthanized 13 and 17 wpi and their carcasses were fed to four laboratory raised opossums. Sporocysts were detected in the feces of two opossums on 15 days post inoculation (dpi) and in a third opossum on 40 dpi. Fecal samples from the fourth opossum remained negative; however, sporocysts were found in intestinal digests from all four opossums. Sporocysts were not found in feces or intestinal digest of an additional opossum that was fed three uninoculated sparrows. Five foals were fed sporocysts (Foals 2, 3, 4, 5, and 7) and two foals were maintained as uninoculated controls (Foals 1 and 6). Sporocysts from two additional feral opossums also were fed to foals. Foal 5 was given 0.05 mg kg-1 dexamethasone sodium phosphate daily beginning 2 days before inoculation for a total of 2 weeks. Horse sera were tested three times per week, and cerebrospinal fluid (CSF) samples were tested biweekly for anti-Sarcocystis neurona antibodies by Western blot analysis. No foals had any S. neurona-specific antibodies by Western blot analysis prior to sporocysts ingestion. Seroconversion occurred in Foals 3, 5, and 7 by 24 dpi, followed by positive CSF tests on 28 dpi. Foals 2 and 4 seroconverted by 40 dpi. Cerebrospinal fluid from Foal 2 tested positive by 42 dpi, but Foal 4 remained seronegative throughout the study. Sera and CSF from control Foals 1 and 6 remained seronegative. All foals with positive CSF developed neurologic clinical signs. Neurologic disease

  8. PULMONARY LESIONS CAUSED BY THE LUNGWORM (DIDELPHOSTRONGYLUS HAYESI) IN THE OPOSSUM (DIDELPHIS VIRGINIANA) IN COLIMA, MEXICO.

    Science.gov (United States)

    López-Crespo, Rubén A; López-Mayagoitia, Alfonso; Ramírez-Romero, Rafael; Martínez-Burnes, Julio; Prado-Rebolledo, Omar F; García-Márquez, Luis J

    2017-06-01

    Didelphostrongylus hayesi is an important and prevalent pulmonary nematode in the opossum ( Didelphis virginiana ). An in-depth description of the pulmonary lesions caused by this nematode is lacking. The objective of this investigation was to make a detailed account of the gross, subgross, and microscopic changes that occur in the lungs of opossums naturally infected with D. hayesi. Forty-four opossums trapped in the state of Colima, Mexico, were euthanized by an overdose of barbiturates. Following a postmortem examination, the right lung was cut from the main bronchi and placed in a Petri dish containing a saline solution for the detection and identification of live parasites. The left lung was fixed and cut serially for subgross microscopic examination and sections of lung were cut and stained for histopathologic examination. The most remarkable gross change in parasitized lungs was a poorly collapsible pulmonary parenchyma and mild emphysema. The right lung tested positive for lungworms on gross examination in 20/44, and 11/44 (25%) of the left lungs showed tan nodules on the pleural surface. Microscopically, the bronchi of 20/44 animals harbored adult and larval stages of D. hayesi (left lung), the same 20 opossums from which nematodes were grossly evident at necropsy (right lung). Adults and larvae were present in bronchi, bronchioles, and alveoli mixed with desquamated cells and many eosinophils, and to a lesser extent neutrophils, alveolar macrophages, and giant cells. Bronchi and bronchioles exhibited goblet cell hyperplasia and metaplasia respectively, and infiltration of lymphoplasmacytic cells in the interstitium and lamina propria. The tan nodules consisted of focal alveolar endogenous lipidosis, which likely resulted from parasitic airway obstruction. The lungs of 3/20 parasitized opossums also showed alveolar bronchiolization (Lambertosis). The absence of Eucoleus aerophilus or bacterial pneumonia incriminates D. hayesi as the putative cause of

  9. Helminths of three species of opossums (Mammalia, Didelphidae) from Mexico

    Science.gov (United States)

    Acosta-Virgen, Karla; López-Caballero, Jorge; García-Prieto, Luis; Mata-López, Rosario

    2015-01-01

    Abstract From August 2011 to November 2013, 68 opossums (8 Didelphis sp., 40 Didelphis virginiana, 15 Didelphis marsupialis, and 5 Philander opossum) were collected in 18 localities from 12 Mexican states. A total of 12,188 helminths representing 21 taxa were identified (6 trematodes, 2 cestodes, 3 acanthocephalans and 10 nematodes). Sixty-six new locality records, 9 new host records, and one species, the trematode Brachylaima didelphus, is added to the composition of the helminth fauna of the opossums in Mexico. These data, in conjunction with previous records, bring the number of taxa parasitizing the Mexican terrestrial marsupials to 41. Among these species, we recognized a group of helminths typical of didelphids in other parts of the Americas. This group is constituted by the trematode Rhopalias coronatus, the acanthocephalan Oligacanthorhynchus microcephalus and the nematodes Cruzia tentaculata, Gnathostoma turgidum, and Turgida turgida. In general, the helminth fauna of each didelphid species showed a stable taxonomic composition with respect to previously sampled sites. This situation suggests that the rate of accumulation of helminth species in the inventory of these 3 species of terrestrial marsupials in the Neotropical portion of Mexico is decreasing; however, new samplings in the Nearctic portion of this country will probably increase the richness of the helminthological inventory of this group of mammals. PMID:26257556

  10. Helminths of three species of opossums (Mammalia, Didelphidae from Mexico

    Directory of Open Access Journals (Sweden)

    Karla Acosta-Virgen

    2015-07-01

    Full Text Available From August 2011 to November 2013, 68 opossums (8 Didelphis sp., 40 Didelphis virginiana, 15 Didelphis marsupialis, and 5 Philander opossum were collected in 18 localities from 12 Mexican states. A total of 12,188 helminths representing 21 taxa were identified (6 trematodes, 2 cestodes, 3 acanthocephalans and 10 nematodes. Sixty-six new locality records, 9 new host records, and one species, the trematode Brachylaima didelphus, is added to the composition of the helminth fauna of the opossums in Mexico. These data, in conjunction with previous records, bring the number of taxa parasitizing the Mexican terrestrial marsupials to 41. Among these species, we recognized a group of helminths typical of didelphids in other parts of the Americas. This group is constituted by the trematode Rhopalias coronatus, the acanthocephalan Oligacanthorhynchus microcephalus and the nematodes Cruzia tentaculata, Gnathostoma turgidum, and Turgida turgida. In general, the helminth fauna of each didelphid species showed a stable taxonomic composition with respect to previously sampled sites. This situation suggests that the rate of accumulation of helminth species in the inventory of these 3 species of terrestrial marsupials in the Neotropical portion of Mexico is decreasing; however, new samplings in the Nearctic portion of this country will probably increase the richness of the helminthological inventory of this group of mammals.

  11. Metal leaching in mine tailings: short-term impact of biochar and wood ash amendments.

    Science.gov (United States)

    Beauchemin, Suzanne; Clemente, Joyce S; MacKinnon, Ted; Tisch, Bryan; Lastra, Rolando; Smith, Derek; Kwong, John

    2015-01-01

    Biochar is perceived as a promising amendment to reclaim degraded, metal-contaminated lands. The objective of this study was to compare the potential of biochar and wood ash amendments to reduce metal(loid) leaching in mine tailings. A 2-mo leaching experiment was conducted in duplicate on acidic and alkaline tailings, each mixed with 5 wt.% of one of the following amendments: three wood-derived, fast-pyrolysis biochars (OC > 57 wt.%) and two wood ash materials (organic carbon [OC] ≤ 16 wt.%); a control test with no carbon input was also added. The columns were leached with water after 1, 2, 4, 8, 16, 32, and 64 d, and the leachates were monitored for dissolved metals, OC, and pH. For the acidic and alkaline tailings, the most significant impact on metal mobility was observed with wood ash materials due to their greater neutralization potential (>15% CaCO eq.) compared with biochar (≤3.3% CaCO eq.). An increase of 1 pH unit in the wood ash-treated alkaline tailings led to an undesirable mobilization of As and Se. The addition of biochar did not significantly reduce the leaching of the main contaminants (Cu and Ni in the acidic tailings and As in the alkaline tailings) over 2 mo. The Se attenuation noted in some biochar-treated acid tailings may be mainly due to a slight alkaline effect rather than Se removal by biochar, given the low capacity for the fresh biochars to retain Se under acidic conditions (pH 4.5). The increased loss of dissolved OC in the biochar-amended systems was of short duration and was not associated with metal(loid) mobilization. Copyright © Her Majesty the Queen in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada.

  12. The effects of Western Diamondback Rattlesnake (Crotalus atrox) venom on the production of antihemorrhagins and/or antibodies in the Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    McKeller, Morgan R; Pérez, John C

    2002-04-01

    Opossums are animals that are naturally resistant to the proteolytic effects of Crotalid venoms. Opossums possess proteinase inhibitors in their sera that bind to and neutralize hemorrhagic and other proteolytic activity in many snake venoms. The proteinase inhibitors are not antibodies since they have different molecular weights (60kDa) and pI (4.2). The purpose of this study was to determine if opossums were capable of producing antibodies against venom and/or increasing the production of proteinase inhibitors (specifically antihemorrhagins). Five different venom immunization protocols were used to determine the effects of the venom in the opossums. The dosages ranged from 1mg of venom per immunization to 350mg/kg body weight of venom per immunization. The antihemorrhagic response was increased, but there is no evidence to suggest that an opossum can produce antibodies against venom. The lack of an antibody response is most likely due to the natural proteinase inhibitors clearing the venom from the opossum's body before an antibody response can occur.

  13. Molecular characterization of Sarcocystis neurona strains from opossums (Didelphis virginiana) and intermediate hosts from Central California.

    Science.gov (United States)

    Rejmanek, Daniel; Miller, Melissa A; Grigg, Michael E; Crosbie, Paul R; Conrad, Patricia A

    2010-05-28

    Sarcocystis neurona is a significant cause of neurological disease in horses and other animals, including the threatened Southern sea otter (Enhydra lutris nereis). Opossums (Didelphis virginiana), the only known definitive hosts for S. neurona in North America, are an introduced species in California. S. neurona DNA isolated from sporocysts and/or infected tissues of 10 opossums, 6 horses, 1 cat, 23 Southern sea otters, and 1 harbor porpoise (Phocoena phocoena) with natural infections was analyzed based on 15 genetic markers, including the first internal transcribed spacer (ITS-1) region; the 25/396 marker; S. neurona surface antigen genes (snSAGs) 2, 3, and 4; and 10 different microsatellites. Based on phylogenetic analysis, most of the S. neurona strains segregated into three genetically distinct groups. Additionally, fifteen S. neurona samples from opossums and several intermediate hosts, including sea otters and horses, were found to be genetically identical across all 15 genetic markers, indicating that fatal encephalitis in Southern sea otters and equine protozoal myeloencephalitis (EPM) in horses is strongly linked to S. neurona sporocysts shed by opossums. (c) 2010 Elsevier B.V. All rights reserved.

  14. Prevalence and tissue distribution of Besnoitia darlingi cysts in the Virginia opossum (Didelphis virginiana) in Michigan.

    Science.gov (United States)

    Elsheikha, Hany M; Mansfield, Linda S; Fitzgerald, Scott D; Saeed, Mahdi A

    2003-08-14

    Specimens of Virginia opossums (Didelphis virginiana) in Michigan were examined over 1 year to document the presence of Besnoitia darlingi cysts. Cyst morphology, prevalence, seasonal variation, and tissue sites of isolation were studied. Histology and ultrastructural features of the detected cysts and bradyzoites were consistent with B. darlingi. In the opossums, B. darlingi had intracellular tissue cysts. Tissue cysts had a mean diameter of 560 microm and were separated from the host tissue by a thick (5-20 microm) cyst wall. Overall prevalence of B. darlingi cysts in opossums was 10.9% (15/137). Variations in the prevalence were detected during spring (3/17; 17.6%), summer (10/34; 29.4%), and fall (2/60; 3.3%). No cysts were detected in the specimens examined during winter (0/26; 0%). Numerous B. darlingi cysts were detected in ears, conjunctiva, tongue, abdominal muscles, diaphragm, stomach, heart, liver, kidney, lung, and spleen. Cysts were detected mainly in adult female opossums that were debilitated. Ear was the most frequent organ from which the cysts were reported (10/15; 66.7%) when compared individually with other body tissues (P<0.05).

  15. Isolation in immunodeficient mice of Sarcocystis neurona from opossum (Didelphis virginiana) faeces, and its differentiation from Sarcocystis falcatula.

    Science.gov (United States)

    Dubey, J P; Lindsay, D S

    1998-12-01

    Sarcocystis neurona was isolated in nude mice and gamma-interferon knockout mice fed sporocysts from faeces of naturally infected opossums (Didelphis virginiana). Mice fed sporocysts became lethargic and developed encephalitis. Protozoa were first found in the brain starting 21 days post-inoculation. Sarcocystis neurona was recovered in cell culture from the homogenate of liver, spleen and brain of a nude mouse 11 days after feeding sporocysts. The protozoa in mouse brain and in cell culture multiplied by schizogony and mature schizonts often had a residual body. Sarcocystis falcatula, which has an avian-opossum cycle, was not infective to nude or knockout mice. Protozoa were not found in tissues of nude mice or knockout mice after subcutaneous injection with culture-derived S. falcatula merozoites and sporocysts from the faeces of opossums presumed to contain only S. falcatula. Results demonstrate that S. neurona is distinct from S. falcatula, and that opossums are hosts for both species.

  16. Evaluation of Cruzia americana, Turgida turgida, and Didelphostrongylus hayesi infection in the Virginia opossum (Didelphis virginiana) and risk factors along the California coast.

    Science.gov (United States)

    Nichelason, Amy E; Rejmanek, Dan; Dabritz, Haydee A; Melli, Ann C; Miller, Melissa; Conrad, Patricia A

    2008-10-01

    Three nematodes, Turgida turgida, Cruzia americana, and Didelphostrongylus hayesi, have been documented to cause morbidity and mortality in the Virginia opossum (Didelphis virginiana). The present study was designed to determine the frequency of infection of these nematodes in opossums at 2 study sites in California and to determine if there are risk factors associated with shedding of eggs or larvae in the feces. Turgida turgida and C. americana adults were found in 84.4% (stomach; n = 45) and 62.5% (intestinal wash and feces; n = 16) of sampled opossums. Eggs were present in opossum feces (n = 105) less frequently (40% T. turgida and 35.2% C. americana). Didelphostrongylus hayesi larvae were found in 79.0% of opossum feces examined (n = 105). Adult age and wet season (December through April) were significant predictive factors for the presence of T. turgida eggs, whereas the dry season (May through November) was significantly associated with the presence of C. americana eggs in feces. Adult opossums were more likely to have eggs and larvae from all 3 nematodes in the feces.

  17. DNA barcodes effectively identify the morphologically similar Common Opossum (Didelphis marsupialis) and Virginia Opossum (Didelphis virginiana) from areas of sympatry in Mexico.

    Science.gov (United States)

    Cervantes, Fernando A; Arcangeli, Jésica; Hortelano-Moncada, Yolanda; Borisenko, Alex V

    2010-12-01

    Two morphologically similar species of opossum from the genus Didelphis-Didelphis virginiana and Didelphis marsupialis-cooccur sympatrically in Mexico. High intraspecific variation complicates their morphological discrimination, under both field and museum conditions. This study aims to evaluate the utility and reliability of using DNA barcodes (short standardized genome fragments used for DNA-based identification) to distinguish these two species. Sequences of the cytochrome c oxidase subunit I (Cox1) mitochondrial gene were obtained from 12 D. marsupialis and 29 D. virginiana individuals and were compared using the neighbor-joining (NJ) algorithm with Kimura's two-parameter (K2P) model of nucleotide substitution. Average K2P distances were 1.56% within D. virginiana and 1.65% in D. marsupialis. Interspecific distances between D. virginiana and D. marsupialis varied from 7.8 to 9.3% and their barcode sequences formed distinct non-overlapping clusters on NJ trees. All sympatric specimens of both species were effectively discriminated, confirming the utility of Cox1 barcoding as a tool for taxonomic identification of these morphologically similar taxa.

  18. Isolation and characterization of a marsupial DNA photolyase

    International Nuclear Information System (INIS)

    Sabourin, C.L.K.; Ley, R.D.

    1988-01-01

    Post UV-B (280-320 nm) exposure to UV-A (320-400 nm) reverses pyrimidine dimers in the epidermal DNA of the South American opossum Monodelphis domestica. To demonstrate that the observed photorepair is mediated by an enzyme, we have isolated a DNA photolyase from the opossum. DNA photolyase from liver was purified 3000-fold by ammonium sulfate fractionation and phenylsepharose, hydroxylapatite, DEAE-cellulose and DNA-cellulose column chromatography. Heat denaturation completely eliminated the photoreactivating activity. The enzyme was active in the pH range of 5.5 to 8.5 with a pH optimum of 7.5. The enzyme has an apparent molecular weight of 32 000 under nondenaturing conditions. The activity of the enzyme was not affected by sodium chloride up to 250 mM. The action spectrum for the purified DNA photolyase showed activity in the range of 325-475 nm with peak activity at 375 nm. (author)

  19. Humoral Immune Response Kinetics in Philander opossum and Didelphis marsupialis Infected and Immunized by Trypanosoma cruzi Employing an Immunofluorescence Antibody Test

    Directory of Open Access Journals (Sweden)

    Ana Paula Legey

    1999-05-01

    Full Text Available Philander opossum and Didelphis marsupialis considered the most ancient mammals and an evolutionary success, maintain parasitism by Trypanosoma cruzi without developing any apparent disease or important tissue lesion. In order to elucidate this well-balanced interaction, we decided to compare the humoral immune response kinetics of the two didelphids naturally and experimentally infected with T. cruzi and immunized by different schedules of parasite antigens, employing an indirect fluorescence antibody test (IFAT. Both didelphids responded with high serological titers to different immunization routes, while the earliest response occurred with the intradermic route. Serological titers of naturally infected P. opossum showed a significant individual variation, while those of D. marsupialis remained stable during the entire follow-up period. The serological titers of the experimentally infected animals varied according to the inoculated strain. Our data suggest that (1 IFAT was sensitive for follow-up of P. opossum in natural and experimental T. cruzi infections; (2 both P. opossum and D. marsupialis are able to mount an efficient humoral immune response as compared to placental mammals; (3 experimentally infected P. opossum and D. marsupialis present distinct patterns of infection, depending on the subpopulation of T. cruzi, (4 the differences observed in the humoral immune responses between P. opossum and D. marsupialis, probably, reflect distinct strategies selected by these animals during their coevolution with T. cruzi.

  20. Receptors and cGMP signalling mechanism for E. coli enterotoxin in opossum kidney

    International Nuclear Information System (INIS)

    Forte, L.R.; Krause, W.J.; Freeman, R.H.

    1988-01-01

    Receptors for the heat-stable enterotoxin produced by Escherichia coli were found in the kidney and intestine of the North American opossum and in cultured renal cell lines. The enterotoxin markedly increased guanosine 3',5'-cyclic monophosphate (cGMP) production in slices of kidney cortex and medulla, in suspensions of intestinal mucosa, and in the opossum kidney (OK) and rat kangaroo kidney (PtK-2) cell lines. In contrast, atrial natriuretic factor elicited much smaller increases in cGMP levels of kidney, intestine, or cultured kidney cell lines. The enterotoxin receptors in OK cells had a molecular mass of approximately 120 kDa when measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of receptors crosslinked with 125 I-enterotoxin. The occurrence of receptors for the E. coli peptide in OK implies that these receptors may be involved in the regulation of renal tubular function in the opossum. E. coli enterotoxin caused a much larger increase in urine cGMP excretion than did atrial natriuretic factor when these peptides were injected intravenously into opossums. However, atrial natriuretic factor elicited a marked diuresis, natriuresis, and increased urinary excretion of calcium, phosphate, potassium, and magnesium. In contrast, the enterotoxin did not acutely influence OK fluid and electrolyte excretion. Thus the substantial increase in cGMP synthesis produced by the bacterial peptide in OK cortex and medulla in vitro and the increased renal excretion of cGMP in vivo were not associated with changes in electrolyte or water excretion. Whether cGMP represents a second messenger molecule in the kidney is an interesting question that was raised but not answered in this series of experiments

  1. Is Gnathostoma turgidum an annual parasite of opossums? Drastic seasonal changes of infection in Didelphis virginiana in Mexico.

    Science.gov (United States)

    Nawa, Yukifumi; de la Cruz-Otero, María del Carmen; Zazueta-Ramos, Magda Luz; Bojórquez-Contreras, Angel; Sicairos-Félix, Josefina; Campista-León, Samuel; Torres-Montoya, Edith Hilario; Sánchez-Gonzalest, Sergio; Guzmán-Loreto, Roberto; Delgado-Vargas, Francisco; Díaz-Camacho, Sylvia Páz

    2009-08-01

    Gnathostoma turgidum is a nematode that parasitizes the stomach of opossums, Didelphis virginiana. Despite its wide distribution in the Americas, its natural life cycle is poorly understood. Recently, we found an endemic area for G. turgidum infection in Sinaloa, Mexico (Diaz-Camacho et al., 2009). Based on sporadic surveys for several years, the prevalence was apparently high in summer and extremely low in winter. To confirm that this is really a seasonal variance, we conducted a longitudinal survey on G. turgidum infection in opossums from November 2007 to November 2008. The results showed amazing seasonal changes in the prevalence, with synchronized migration and maturation of worms in opossums. Between February and March, many juvenile worms, with occasional AL3, were found in the liver, but no worms were found in the stomach. Mature adult worms began to appear in the stomach around April and rapidly increased in number toward July, when all worms resided in the stomach. Then, the worms disappeared almost completely by November. These results suggest that G. turgidum is an annual parasite of the opossum, D. virginiana, in Mexico.

  2. CUTANEOUS EPITHELIOTROPIC T-CELL LYMPHOMA WITH METASTASES IN A VIRGINIA OPOSSUM (DIDELPHIS VIRGINIANA).

    Science.gov (United States)

    Higbie, Christine T; Carpenter, James W; Choudhary, Shambhunath; DeBey, Brad; Bagladi-Swanson, Mary; Eshar, David

    2015-06-01

    A 2-yr-old, captive, intact female Virginia opossum ( Didelphis virginiana ) with a 7-mo history of ulcerative dermatitis and weight loss was euthanatized for progressive worsening of clinical signs. Initially the opossum was treated with several courses of antibiotics, both topically and systemically; systemic nonsteroidal anti-inflammatory medication; and, later, systemic glucocorticoids, with no improvement in clinical signs. Histopathologic samples of skin lesions taken 3 mo into the course of disease revealed no evidence of neoplasia; however, cytologic samples of a skin lesion taken 5 mo into the course of disease revealed mature lymphocytes, and were suggestive of cutaneous lymphoma. Postmortem histopathology revealed neoplastic cells consistent with lymphoma; these were found in the haired skin of the forearm, axilla, hind limb, face, and lateral body wall, as well as the liver, kidney, axillary lymph node, heart, and spleen. Multifocal neutrophilic and eosinophilic ulcerative and necrotizing dermatitis and folliculitis of the haired skin were also present. To the authors' knowledge, this is the first documented case of cutaneous lymphoma in a Virginia opossum and the first documented case with visceral metastases in a marsupial.

  3. Evidence for exploitative competition: Comparative foraging behavior and roosting ecology of short-tailed fruit bats (Phyllostomidae)

    Science.gov (United States)

    Bonaccorso, F.J.; Winkelmann, J.R.; Shin, D.; Agrawal, C.I.; Aslami, N.; Bonney, C.; Hsu, A.; Jekielek, P.E.; Knox, A.K.; Kopach, S.J.; Jennings, T.D.; Lasky, J.R.; Menesale, S.A.; Richards, J.H.; Rutland, J.A.; Sessa, A.K.; Zhaurova, L.; Kunz, T.H.

    2007-01-01

    Chestnut short-tailed bats, Carollia castanea, and Seba's short-tailed bats, C. perspicillata (Phyllostomidae), were radio-tracked (N = 1593 positions) in lowland rain forest at Tiputini Biodiversity Station, Orellana Province, Ecuador. For 11 C. castanea, mean home range was 6.8 ?? 2.2 ha, mean core-use area was 1.7 ?? 0.8 ha, and mean long axis across home range was 438 ?? 106 m. For three C. perspicillata, mean home range was 5.5 ?? 1.7 ha, mean core-use area was 1.3 ?? 0.6 ha, and mean long axis was 493 ?? 172 m. Groups of less than five C. castanea occupied day-roosts in earthen cavities that undercut banks the Tiputini River. Carollia perspicillata used tree hollows and buildings as day-roosts. Interspecific and intraspecific overlap among short-tailed bats occurred in core-use areas associated with clumps of fruiting Piper hispidum (peppers) and Cecropia sciadophylla. Piper hispidum seeds were present in 80 percent of the fecal samples from C. castanea and 56 percent of samples from C. perspicillata. Carollia perspicillata handled pepper fruits significantly faster than C. castanea; however, C. castanea commenced foraging before C. perspicillata emerged from day-roosts. Evidence for exploitative competition between C. castanea and C. perspicillata is suggested by our observations that 95 percent of ripe P. hispidum fruits available at sunset disappear before sunrise (N = 74 marked fruits). Piper hispidum plants produced zero to 12 ripe infructescences per plant each night during peak production. Few ripe infructescences of P. hispidum were available during the dry season; however, ripe infructescences of C. sciadophylla, remained abundant. ?? 2007 The Author(s) Journal compilation ?? 2007 by The Association for Tropical Biology and Conservation.

  4. Molecular characterization of Sarcocystis neurona strains from opossums (Didelphis virginiana) and intermediate hosts from Central California

    OpenAIRE

    Rejmanek, Daniel; Miller, Melissa A.; Grigg, Michael E.; Crosbie, Paul R.; Conrad, Patricia A.

    2010-01-01

    Sarcocystis neurona is a significant cause of neurological disease in horses and other animals, including the threatened Southern sea otter (Enhydra lutris nereis). Opossums (Didelphis virginiana), the only known definitive hosts for S. neurona in North America, are an introduced species in California. S. neurona DNA isolated from sporocysts and/or infected tissues of 10 opossums, 6 horses, 1 cat, 23 Southern sea otters, and 1 harbor porpoise (Phocoena phocoena) with natural infections was an...

  5. Comparative genomics and proteomics of vertebrate diacylglycerol acyltransferase (DGAT), acyl CoA wax alcohol acyltransferase (AWAT) and monoacylglycerol acyltransferase (MGAT).

    Science.gov (United States)

    Holmes, Roger S

    2010-03-01

    BLAT (BLAST-Like Alignment Tool) analyses of the opossum (Monodelphis domestica) and zebrafish (Danio rerio) genomes were undertaken using amino acid sequences of the acylglycerol acyltransferase (AGAT) superfamily. Evidence is reported for 8 opossum monoacylglycerol acyltransferase-like (MGAT) (E.C. 2.3.1.22) and diacylglycerol acyltransferase-like (DGAT) (E.C. 2.3.1.20) genes and proteins, including DGAT1, DGAT2, DGAT2L6 (DGAT2-like protein 6), AWAT1 (acyl CoA wax alcohol acyltransferase 1), AWAT2, MGAT1, MGAT2 and MGAT3. Three of these genes (AWAT1, AWAT2 and DGAT2L6) are closely localized on the opossum X chromosome. Evidence is also reported for six zebrafish MGAT- and DGAT-like genes, including two DGAT1-like genes, as well as DGAT2-, MGAT1-, MGAT2- and MGAT3-like genes and proteins. Predicted primary, secondary and transmembrane structures for the opossum and zebrafish MGAT-, AWAT- and DGAT-like subunits and the intron-exon boundaries for genes encoding these enzymes showed a high degree of similarity with other members of the AGAT superfamily, which play major roles in triacylglyceride (DGAT), diacylglyceride (MGAT) and wax ester (AWAT) biosynthesis. Alignments of predicted opossum, zebrafish and other vertebrate DGAT1, DGAT2, other DGAT2-like and MGAT-like amino acid sequences with known human and mouse enzymes demonstrated conservation of residues which are likely to play key roles in catalysis, lipid binding or in maintaining structure. Phylogeny studies of the human, mouse, opossum, zebrafish and pufferfish MGAT- and DGAT-like enzymes indicated that the common ancestors for these genes predated the appearance of bony fish during vertebrate evolution whereas the AWAT- and DGAT2L6-like genes may have appeared more recently prior to the appearance of marsupial and eutherian mammals. Copyright 2009 Elsevier Inc. All rights reserved.

  6. Impaired Short-Term Functioning of a Benthic Community from a Deep Norwegian Fjord Following Deposition of Mine Tailings and Sediments

    Directory of Open Access Journals (Sweden)

    Lisa Mevenkamp

    2017-05-01

    Full Text Available The extraction of minerals from land-based mines necessitates the disposal of large amounts of mine tailings. Dumping and storage of tailings into the marine environment, such as fjords, is currently being performed without knowing the potential ecological consequences. This study investigated the effect of short-term exposure to different deposition depths of inert iron ore tailings (0.1, 0.5, and 3 cm and dead subsurface sediment (0.5 and 3 cm on a deep water (200 m fjord benthic assemblage in a microcosm experiment. Biotic and abiotic variables were measured to determine structural and functional changes of the benthic community following an 11 and 16 day exposure with tailings and dead sediment, respectively. Structural changes of macrofauna, meiofauna, and bacteria were measured in terms of biomass, density, community composition and mortality while measures of oxygen penetration depth, sediment community oxygen consumption and 13C-uptake and processing by biota revealed changes in the functioning of the system. Burial with mine tailings and natural sediments modified the structure and functioning of the benthic community albeit in a different way. Mine tailings deposition of 0.1 cm and more resulted in a reduced capacity of the benthic community to remineralize fresh 13C-labeled algal material, as evidenced by the reduced sediment community oxygen consumption and uptake rates in all biological compartments. At 3 cm of tailings deposition, it was evident that nematode mortality was higher inside the tailings layer, likely caused by reduced food availability. In contrast, dead sediment addition led to an increase in oxygen consumption and bacterial carbon uptake comparable to control conditions, thereby leaving deeper sediment layers anoxic and in turn causing nematode mortality at 3 cm deposition. This study clearly shows that even small levels (0.1 cm of instantaneous burial by mine tailings may significantly reduce benthic ecosystem

  7. Antiinflammatory agents protect opossum esophagus during radiotherapy

    International Nuclear Information System (INIS)

    Northway, M.G.; Eastwood, G.L.; Libshitz, H.I.; Feldman, M.S.; Mamel, J.J.; Szwarc, I.A.

    1982-01-01

    Eighteen opossums received 2250 rad 60 Co to the entire esophagus and lower esophageal sphincter. Animals received treatment with 600 mg aspirin, 25 mg/kg hydrocortisone, or saline before irradiation and twice daily for 1 week after irradiation. At 10 days postirradiation, animals were evaluated for signs of acute esophagitis by esophagoscopy and barium esophagram. Each animal was then killed and the esophagus removed and evaluated histologically. Animals treated with either aspirin or hydrocortisone had significantly milder esophagitis than control irradiated animals

  8. Isolation of Salmonella enterica and serologic reactivity to Leptospira interrogans in opossums (Didelphis virginiana) from Yucatán, México.

    Science.gov (United States)

    Ruiz-Pina, Hugo Antonio; Puc-Franco, Miguel Angel; Flores-Abuxapqui, Javier; Vado-Solis, Ignacio; Cardenas-Marrufo, María Fidelia

    2002-01-01

    The presence of Salmonella enterica and serologic evidence of infection by Leptospira interrogans, were detected in the opossum Didelphis virginiana in a semi-urban locality of the Yucatán State, México. Ninety-one opossums were captured during the period April 1996 and May 1998. From a total of 17 feces samples, four Salmonella enterica subsp. enterica serotypes (Sandiego, Newport, Anatum, and Minnesota), and one Salmonella enterica subsp. arizonae serovar O44:Z4,Z23:- were isolated. Some opossums presented mixed infections. From 81 sera samples, four (4.9%) were positive to antibodies to Leptospira serovars pomona and wolfii. Both animals infected with Salmonella enterica and those serologically positive to Leptospira interrogans were captured in peridomestic habitat. Opossums infected with Salmonella enterica, were captured in dry season, and those seropositive to Leptospira interrogans during the rainy season. The implications of infection and reactivity of these zoonotic pathogens in D. virginiana in the Yucatan state are briefly discussed.

  9. Adult-onset demodicosis in two dogs due to Demodex canis and a short-tailed demodectic mite.

    Science.gov (United States)

    Saridomichelakis, M; Koutinas, A; Papadogiannakis, E; Papazachariadou, M; Liapi, M; Trakas, D

    1999-11-01

    Infestation with a short-tailed demodectic mite and Demodex canis was diagnosed in both a six-and-a-half-year-old and a four-year-old dog. The clinical picture was compatible with generalised demodicosis complicated by staphylococcal pyoderma (case 1), or localised demodicosis (case 2). In both cases, the short-tailed demodectic mite outnumbered D canis in superficial skin scrapings. The laboratory findings (lymphopenia, eosinopenia, increased serum alkaline phosphatase and alanine aminotransferase activities, diluted urine and proteinuria) and the results of a low dose dexamethasone suppression test were suggestive of underlying hyperadrenocorticism in the first case. Hypothyroidism was considered a possibility in the second case, owing to the sustained bradycardia and the extremely low basal total thyroxine value. Systemic treatment with ivermectin and cephalexin (case 1), or topical application of an amitraz solution in mineral oil, along with sodium levothyroxine replacement therapy (case 2), resulted in a complete resolution of the skin lesions and the disappearance of both types of demodectic mite after two and one and a half months, respectively.

  10. Sporocyst size of isolates of Sarcocystis shed by the Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    Cheadle, M A; Dame, J B; Greiner, E C

    2001-02-26

    The Virginia opossum (Didelphis virginiana) is a definitive host for multiple Sarcocystis species including Sarcocystis neurona, one of the causative agents of equine protozoal myeloencephalitis (EPM), a severe, neuromuscular disease of horses. Size and morphologic characteristics of isolates of Sarcocystis shed by the opossum were examined to determine if differences were useful in discriminating between the isolates and/or species. Collections of sporocysts from 17 opossums were molecularly characterized and measured using an ocular micrometer. The mean sporocyst size of isolates of S. neurona was 10.7 microm x 7.0 microm, Sarcocystis falcatula 11.0 microm x 7.1 microm, Sarcocystis speeri 12.2 microm x 8.8 microm, 1085-like isolate 10.9 microm x 6.8 microm, and 3344-like isolate 19.4 microm x 10.5 microm. The length and width of S. speeri were statistically different (p < 0.05) from the sporocysts of other types. The length of S. neurona and S. falcatula sporocysts were statistically different (p < 0.05) from each other and the width of S. falcatula and 1085 differed (p < 0.05). The fifth sporocyst type (3344) was observed, but due to pronounced morphological characteristics, statistical analysis was not performed. There was no consistent difference between the taxa based on internal structure of the sporocyst.

  11. Aerobic bacteria cultured from the mouth of the American opossum (Didelphis virginiana) with reference to bacteria associated with bite infections.

    OpenAIRE

    Howell, J M; Dalsey, W C

    1990-01-01

    The American opossum inflicts bite injuries both when hunted for food and when accidentally provoked when handled in captivity. This study involved aerobically culturing organisms from the mouths of seven wild opossums (Didelphis virginiana). Isolates included streptococci, coagulase-positive and -negative staphylococci, Aeromonas spp., Citrobacter freundii, Eikenella corrodens, and Escherichia coli.

  12. Tail docking in pigs: a review on its short- and long-term consequences and effectiveness in preventing tail biting

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    Eleonora Nannoni

    2014-02-01

    Full Text Available In spite of European legislation attempting to limit this practice, tail docking is nowadays the only preventive measure against tail biting which is widely adopted by farmers. Docking consists in amputating, usually without anaesthesia or analgesia, the distal part of the tail, in order to reduce its attractiveness and to sensitize it, increasing avoidance behaviour in the bitten pig. Tail docking results in both acute and chronic effects on pig welfare, and its effectiveness in preventing tail biting is limited, since it reduces the symptoms of a behavioural disorder, but does not address the underlying causes. The aim of the present paper is to review the available literature on the effects of tail docking on swine welfare. Although from a practical standpoint the welfare risks arising from tail docking may appear to be negligible compared to those arising during and after tail biting outbreaks, it should be considered that, apart from acute physiological and behavioural responses, tail docking may also elicit long-term effects on weight gain, tail stump sensitivity and animal freedom to express their normal behaviour. Such chronic effects have been poorly investigated so far. Besides, studies evaluating the effectiveness of anaesthetics or analgesic treatments are often conflicting. Within this framework, further research is recommended in order to reduce the acute and chronic pain and discomfort experienced by the animals, until preventive measures (e.g., environmental enrichment, stocking densities are broadly adopted to prevent tail biting.

  13. Aerobic bacteria cultured from the mouth of the American opossum (Didelphis virginiana) with reference to bacteria associated with bite infections.

    Science.gov (United States)

    Howell, J M; Dalsey, W C

    1990-01-01

    The American opossum inflicts bite injuries both when hunted for food and when accidentally provoked when handled in captivity. This study involved aerobically culturing organisms from the mouths of seven wild opossums (Didelphis virginiana). Isolates included streptococci, coagulase-positive and -negative staphylococci, Aeromonas spp., Citrobacter freundii, Eikenella corrodens, and Escherichia coli. PMID:2229365

  14. Erythrocyte glucose-6-phosphate dehydrogenase from Brazilian opossum Didelphis marsupialis

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    Barretto O.C. de O.

    2006-01-01

    Full Text Available In a comparative study of erythrocyte metabolism of vertebrates, the specific activity of glucose-6-phosphate dehydrogenase (G6PD of the Brazilian opossum Didelphis marsupialis in a hemolysate was shown to be high, 207 ± 38 IU g-1 Hb-1 min-1 at 37ºC, compared to the human erythrocyte activity of 12 ± 2 IU g-1 Hb-1 min-1 at 37ºC. The apparent high specific activity of the mixture led us to investigate the physicochemical properties of the opossum enzyme. We report that reduced glutathione (GSH in the erythrocytes was only 50% higher than in human erythrocytes, a value lower than expected from the high G6PD activity since GSH is maintained in a reduced state by G6PD activity. The molecular mass, determined by G-200 Sephadex column chromatography at pH 8.0, was 265 kDa, which is essentially the same as that of human G6PD (260 kDa. The Michaelis-Menten constants (Km: 55 µM for glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate (Km: 3.3 µM were similar to those of the human enzyme (Km: 50-70 and Km: 2.9-4.4, respectively. A 450-fold purification of the opossum enzyme was achieved and the specific activity of the purified enzyme, 90 IU/mg protein, was actually lower than the 150 IU/mg protein observed for human G6PD. We conclude that G6PD after purification from the hemolysate of D. marsupialis does not have a high specific activity. Thus, it is quite probable that the red cell hyperactivity reported may be explained by increased synthesis of G6PD molecules per unit of hemoglobin or to reduced inactivation in the RBC hemolysate.

  15. Prevalence of agglutinating antibodies to Sarcocystis neurona in skunks (Mephitis Mephitis), raccoons (Procyon lotor), and opossums (Didelphis Virginiana) from Connecticut.

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    Mitchell, Sheila M; Richardson, Dennis J; Cheadle, M Andy; Zajac, Anne M; Lindsay, David S

    2002-10-01

    Equine protozoal myeloencephalitis is the most important protozoan disease of horses in North America and is usually caused by Sarcocystis neurona. Natural cases of encephalitis caused by S. neurona have been reported in skunks (Mephitis mephitis) and raccoons (Procyon lotor). Opossums (Didelphis spp.) are the only known definitive host. Sera from 24 striped skunks, 12 raccoons, and 7 opossums (D. virginiana) from Connecticut were examined for agglutinating antibodies to S. neurona using the S. neurona agglutination test (SAT) employing formalin-fixed merozoites as antigen. The SAT was validated for skunk sera using pre- and postinfection serum samples from 2 experimentally infected skunks. Of the 24 (46%) skunks 11 were positive, and all 12 raccoons were positive for S. neurona antibodies. None of the 7 opossums was positive for antibodies to S. neurona. These results suggest that exposure to sporocysts of S. neurona by intermediate hosts is high in Connecticut. The absence of antibodies in opossums collected from the same areas is most likely because of the absence of systemic infection in the definitive host.

  16. Body size of commom opossum Didelphis aurita Wied-Neuwied 1826 (Didelphimorphia: Didelphidae on southern brazilian islands

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    CH. Salvador

    Full Text Available The body size of vertebrates isolated on islands can undergo changes due to ecological features of these environments. This study aimed to compare the body size of the common opossum, Didelphis aurita, from different insular populations within the same archipelago in southern Brazil. The opossum populations showed corporal variation and different hypotheses were raised to understand the results. This study constitutes the most detailed body size comparison of a marsupial within different insular populations in the Neotropical zone and the data gathered represents an initial contribution for regional fauna biometric knowledge.

  17. Infection of Anaplasma phagocytophilum and Ehrlichia spp. in Opossums and Dogs in Campeche, Mexico: The Role of Tick Infestation

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    Edgar Rojero-Vázquez

    2017-12-01

    Full Text Available In recent years, some tick-borne diseases such as anaplasmosis and ehrlichiosis became widespread worldwide, threatening the health of humans, domestic animals and wildlife. The aims of this study were to determine the presence of Anaplasma phagocytophilum, Ehrlichia canis, and Ehrlichia chaffeensis in 102 opossums (Didelphis spp. and 44 owned free-ranging dogs in southeastern Mexico using a specific polymerase chain reaction (PCR. A. phagocytophilum was detected in opossums and dogs with a prevalence of 3 and 27%, respectively. E. canis was only present in 7% of dogs, while we didn't detect E. chaffeensis in any host. We report the first evidence of infections of A. phagocytophilum in Didelphis virginiana and D. marsupialis in Mexico. The infection rates and patterns we found of A. phagocytophilum suggest that dogs are more directly involved in the ecology of this pathogen than opossums. Despite the small prevalence found, our results are of public health concern because of the zoonotic capabilities of A. phagocytophilum, the high tick infestation rates found and because both opossums and free-ranging dogs can achieve high population densities in the region.

  18. Development and characterization of fourteen novel microsatellite markers for the chestnut short-tailed fruit bat (Carollia castanea), and cross-amplification to related species.

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    Cleary, Katherine A; Waits, Lisette P; Hohenlohe, Paul A

    2016-01-01

    Rapid anthropogenic land use change threatens the primary habitat of the Chestnut short-tailed bat (Carollia castanea) throughout much of its range. Information on population genetic structure can inform management strategies for this widespread frugivorous bat, and effective protection of C. castanea will also benefit the more than 20 mutualistic plant species of which this bat is the primary seed disperser. To facilitate understanding of population genetic structure in this species, fourteen novel microsatellite markers were developed using restriction-site-associated DNA libraries and Illumina sequencing and tested on 28 individuals from 13 locations in Costa Rica. These are the first microsatellite markers developed for C. castanea. All loci were polymorphic, with number of alleles ranging from 2-11 and average observed heterozygosity of 0.631. Markers were also cross-amplified in three additional frugivorous bat species threatened by habitat loss and fragmentation: Sowell's short-tailed bat (Carollia sowelli), Seba's short-tailed bat (Carollia perspicillata), and the Jamaican fruit bat (Artibeus jamaicensis), and 10, 11, and 8 were polymorphic, respectively.

  19. INFECTION BY Rickettsia felis IN OPOSSUMS (Didelphis sp.) FROM YUCATAN, MEXICO.

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    Peniche-Lara, Gaspar; Ruiz-Piña, Hugo A; Reyes-Novelo, Enrique; Dzul-Rosado, Karla; Zavala-Castro, Jorge

    2016-01-01

    Rickettsia felis is an emergent pathogen and the causative agent of a typhus-like rickettsiosis in the Americas. Its transmission cycle involves fleas as biological vectors (mainly Ctenocephalides felis) and multiple domestic and synanthropic mammal hosts. Nonetheless, the role of mammals in the cycle of R. felis is not well understood and many efforts are ongoing in different countries of America to clarify it. The present study describes for the first time in Mexico the infection of two species of opossum (Didelphis virginiana and D. marsupialis) by R. felis. A diagnosis was carried out from blood samples by molecular methods through the gltA and 17 kDa genes and sequence determination. Eighty-seven opossum samples were analyzed and 28 were found to be infected (32.1%) from five out of the six studied localities of Yucatan. These findings enable recognition of the potential epidemiological implications for public health of the presence of infected synanthropic Didelphis in households.

  20. INFECTION BY Rickettsia felis IN OPOSSUMS (Didelphis sp. FROM YUCATAN, MEXICO

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    Gaspar PENICHE-LARA

    2016-01-01

    Full Text Available Rickettsia felis is an emergent pathogen and the causative agent of a typhus-like rickettsiosis in the Americas. Its transmission cycle involves fleas as biological vectors (mainly Ctenocephalides felis and multiple domestic and synanthropic mammal hosts. Nonetheless, the role of mammals in the cycle of R. felis is not well understood and many efforts are ongoing in different countries of America to clarify it. The present study describes for the first time in Mexico the infection of two species of opossum (Didelphis virginiana and D. marsupialis by R. felis. A diagnosis was carried out from blood samples by molecular methods through the gltAand 17 kDa genes and sequence determination. Eighty-seven opossum samples were analyzed and 28 were found to be infected (32.1% from five out of the six studied localities of Yucatan. These findings enable recognition of the potential epidemiological implications for public health of the presence of infected synanthropic Didelphis in households.

  1. Morphological observations on the metanephros in the postnatal opossum, Didelphis virginiana.

    Science.gov (United States)

    Krause, W J; Cutts, J H; Leeson, C R

    1979-10-01

    The metanephros of the newborn opossum is very immature, consisting only of collecting tubules and a few immature nephrons. Development during the postnatal period can be divided into two distinct phases. The initial phase occurs during the first 60 days of postnatal life and is concerned with nephronogenesis and the differentiation of nephrons that have formed during this period. The second phase lasts through the remainder of the postnatal period and is concerned with further differentiation and growth of established nephrons. During this latter period the tubular portion of the nephron increases in length and the renal corpuscle increases in diameter. Ultrastructural observations suggest that metanephric nephrons are not functional during the first 4 days of postnatal life, while the mesonephros reaches the height of its development during this period: there may be some functional overlap between the mesonephros and metanephros during the latter part of the first week of postnatal life. The pattern of nephron induction and differentiation in the opossum is discussed.

  2. The opossum Didelphis virginiana as a synanthropic reservoir of Trypanosoma cruzi in Dzidzilché, Yucatán, México.

    Science.gov (United States)

    Ruiz-Pina, Hugo A; Cruz-Reyes, Alejandro

    2002-07-01

    In México, the role of mammals in the transmission cycle of Trypanosoma cruzi is poorly known. In the State of Yucatán, an endemic area of Chagas disease, both Didelphis virginiana and D. marsupialis occur sympatrically. However, until now, only the former species had been found infected with T. cruzi. To evaluate the role of D. virginiana in a peridomestic transmission, nine periods of capture-recapture were performed around the village of Dzidzilché, Yucatán. The sex, age, reproductive status, location, and presence of infection with T. cruzi were recorded for each opossum. The chromosome morphology was used to identify the opossum species. T. cruzi was identified by the presence of pseudocysts of amastigotes in cardiac muscle fibers of Balb/c mice inoculated with strains isolated from opossums. However, xenodiagnosis was the best diagnostic method. Triatoma dimidiata, the vector, were collected in and around the opossums' nests, and human dwellings; and were checked for T. cruzi. From 102 blood samples of D. virginiana examined 55 (53.9%) were positive to T. cruzi, the only two D. marsupialis captured were negative. Significant differences were found between infection, and both sex and reproductive condition. Eight out of 14 triatomines collected in peridomestic nests (57.1%), and 32 of 197 captured inside houses (16.3%) were found infected, suggesting a peridomestic transmission. The statistically high abundance of infected opossums and triatomines during the dry season (March to May) suggested the existence of a seasonality in the peridomestic transmission of T. cruzi in Dzidzilché.

  3. The opossum Didelphis virginiana as a synanthropic reservoir of Trypanosoma cruzi in Dzidzilché, Yucatán, México

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    Hugo A Ruiz-Piña

    2002-07-01

    Full Text Available In México, the role of mammals in the transmission cycle of Trypanosoma cruzi is poorly known. In the State of Yucatán, an endemic area of Chagas disease, both Didelphis virginiana and D. marsupialis occur sympatrically. However, until now, only the former species had been found infected with T. cruzi. To evaluate the role of D. virginiana in a peridomestic transmission, nine periods of capture-recapture were performed around the village of Dzidzilché, Yucatán. The sex, age, reproductive status, location, and presence of infection with T. cruzi were recorded for each opossum. The chromosome morphology was used to identify the opossum species. T. cruzi was identified by the presence of pseudocysts of amastigotes in cardiac muscle fibers of Balb/c mice inoculated with strains isolated from opossums. However, xenodiagnosis was the best diagnostic method. Triatoma dimidiata, the vector, were collected in and around the opossums' nests, and human dwellings; and were checked for T. cruzi. From 102 blood samples of D. virginiana examined 55 (53.9% were positive to T. cruzi, the only two D. marsupialis captured were negative. Significant differences were found between infection, and both sex and reproductive condition. Eight out of 14 triatomines collected in peridomestic nests (57.1%, and 32 of 197 captured inside houses (16.3% were found infected, suggesting a peridomestic transmission. The statistically high abundance of infected opossums and triatomines during the dry season (March to May suggested the existence of a seasonality in the peridomestic transmission of T. cruzi in Dzidzilché.

  4. Isolation of a third species of Sarcocystis in immunodeficient mice fed feces from opossums (Didelphis virginiana) and its differentiation from Sarcocystis falcatula and Sarcocystis neurona.

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    Dubey, J P; Speer, C A; Lindsay, D S

    1998-12-01

    Opossums (Didelphis virginiana) were found to be hosts for 3 species of Sarcocystis: Sarcocystis falcatula with an avian intermediate host, S. neurona with an undetermined intermediate host, and a third, unnamed, species. Sporocysts from the intestines of 2 opossums (nos. 26 and 47) were fed to budgerigars (Melopsittacus undulatus), nude mice, and gamma-interferon knockout (KO) mice. Sporocysts of S. falcatula were not infective to nude or KO mice. Sporocysts of S. neurona induced encephalitis in KO and nude mice; only schizonts and merozoites were found in tissues of mice, and they reacted with anti-S. neurona serum raised against the SN-2 isolate of S. neurona originally obtained from tissues of a paralyzed horse. All 3 species of Sarcocystis were present in opossum no. 47. Sarcocystis neurona was isolated in cell culture from this opossum. Sporocysts from opossum no. 47 were lethal to budgerigars, indicating S. falcatula infection. Only 1 species of Sarcocystis (the third species) was found in opossum no. 26; the sporocysts were infective to KO and nude mice. Schizonts and merozoites of this species were predominantly in the liver but were also found in other tissues; schizonts did not react with anti-S. neurona serum. Merozoites of the third species were ultrastructurally distinct from S. falcatula and S. neurona merozoites. Sarcocysts were found in leg muscles of 2 mice killed 50 and 54 days after they were fed sporocysts from opossum no. 26. These sarcocysts had steeple-shaped protrusions on the cyst wall and were distinct from sarcocysts of S. falcatula and any other species of Sarcocystis.

  5. Discovery of an endemic area of Gnathostoma turgidum infection among opossums, Didelphis virginiana, in Mexico.

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    Díaz-Camacho, Sylvia Páz; Willms, Kaethe; Rendón-Maldonado, José Guadalupe; de la Cruz-Otero, María del Carmen; Delgado-Vargas, Francisco; Robert, Lilia; Antuna, Silvia; León-Règagnon, Virginia; Nawa, Yukifumi

    2009-06-01

    Gnathostomosis, caused by Gnathostoma binucleatum, is a serious public health issue in Mexico. Although 2 other Gnathostoma spp., G. turgidum and G. lamothei, have been found in wild animals, their natural life cycle or their relation to human disease remains unclear. While we were conducting an epidemiological survey on Gnathostoma spp. in Sinaloa State, Mexico, we found an endemic area for G. turgidum in common opossums, Didelphis virginiana, located in Tecualilla, Sinaloa. The species identification was carried out by morphological and molecular biological methods. This is the first record of an endemic area for G. turgidum infection in opossums, D. virginiana, in the Americas.

  6. Anatomical and Radiographic Study on the Skull and Mandible of the Common Opossum (Didelphis Marsupialis Linnaeus, 1758 in the Caribbean

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    Reda Mohamed

    2018-04-01

    Full Text Available Common opossums (Didelphis marsupialis are found throughout the Caribbean island of Trinidad and Tobago. The present work was conducted on 10 skulls and mandibles of the common opossum to describe the osteology and foramina of these skulls and mandibles grossly and radiographically. The information that is garnered can be used to detect, diagnose, and treat head affections, as well as for comparative studies with the skulls and mandibles of other similar species. The skulls and mandibles were prepared and cleaned using standard method. All of the characteristic features of various standards views of the skulls bones, including dorsal, lateral, caudal and midsagittal, and the lateral and caudal views of the mandibles as well as the foramina of the skulls and mandibles were described and discussed. Each skull was divided into long facial and short cranial regions. No supraorbital foramen was observed in the skulls. The tympanic bulla was absent while there was the tympanic process of the alisphenoid. The temporal process of the zygomatic bone, zygomatic process of maxilla, and zygomatic process of the squamosal bone formed the zygomatic arch. The dental formula was confirmed. The bones and foramina of the skull and mandible were similar to other marsupial species and were homologue to that of other mammals.

  7. Seasonal changes in the physiology of male Virginia opossums (Didelphis virginiana): signs of the Dasyurid semelparity syndrome?

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    Woods, Henri A; Hellgren, Eric C

    2003-01-01

    Semelparity, which is multiplying once in a lifetime, is a rare reproductive strategy among mammals. Several species of the marsupial family Dasyuridae experience 100% male mortality following an intense mating period. We investigated seasonal physiological changes that may be associated with early mortality in the male Virginia opossum (Didelphis virginiana; Didelphidae) and compared these changes with those of semelparous, male dasyurids. Free-ranging male Virginia opossums (n=36) were collected during 2001 at the Oklahoma State University Cross Timbers Experimental Range. Seasonal data were collected on hematological, morphological, and helminth parameters of these individuals. We used one-way ANOVA to determine whether there were seasonal differences among means for each parameter. It appeared that male Virginia opossums experienced some physiological changes similar to those of male dasyurids exhibiting semelparity. All males collected in summer (August) were juveniles of the year. Lack of adult males in August suggests high mortality of this cohort during the breeding season. Opossum characteristics exhibiting the dasyurid semelparity syndrome included packed cell volume, adrenal mass, and helminth numbers. Minor lymphocytopenia, neutrophilia, and testosterone concentrations also were similar to semelparous dasyurids. However, a lack of change in serum cortisol concentration and body mass and dynamics in immunoglobulin protein, serum protein, and testes mass were not consistent with previous reports of semelparous dasyurid physiology. Evolutionary divergence and differences in breeding behavior between dasyurids and didelphids may be responsible for the lack of consistency between the taxa.

  8. Sarcocystis inghami n. sp. (Sporozoa: Sarcocystidae) from the skeletal muscles of the Virginia opossum Didelphis virginiana in Michigan.

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    Elsheikha, Hany M; Fitzgerald, Scott D; Mansfield, Linda S; Saeed, A Mahdi

    2003-09-01

    This report describes the newly identified Sarcocystis inghami n. sp. from the skeletal muscles of opossums (Mammalia: Didelphidae) that were collected from south central Michigan (42 degrees 43'-42 degrees 79'N, 84 degrees 18'-84 degrees 86'W), USA. The new species is distinguished from all species described from North and South American opossums by the distinctive morphology of the villar protrusions on the cyst wall. Sarcocysts of S. inghami are microscopic, up to 700 microm long and 110 microm wide. The sarcocyst wall is up to 7 microm thick, with long, stalked protrusions which average 5.5 x 1.2 microm. These are constricted at the base, expanded laterally, rounded off distally and occasionally bifid. The villar protrusions have numerous microtubules without electron-dense bodies that extend from the tips into the granular layer. Bradyzoites are 10.7 x 4.3 (8-12 x 4-5) microm. This is the second species of Sarcocystis sarcocyst described from the Virginia opossum in North America.

  9. Adaptive evolution of the venom-targeted vWF protein in opossums that eat pitvipers.

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    Sharon A Jansa

    Full Text Available The rapid evolution of venom toxin genes is often explained as the result of a biochemical arms race between venomous animals and their prey. However, it is not clear that an arms race analogy is appropriate in this context because there is no published evidence for rapid evolution in genes that might confer toxin resistance among routinely envenomed species. Here we report such evidence from an unusual predator-prey relationship between opossums (Marsupialia: Didelphidae and pitvipers (Serpentes: Crotalinae. In particular, we found high ratios of replacement to silent substitutions in the gene encoding von Willebrand Factor (vWF, a venom-targeted hemostatic blood protein, in a clade of opossums known to eat pitvipers and to be resistant to their hemorrhagic venom. Observed amino-acid substitutions in venom-resistant opossums include changes in net charge and hydrophobicity that are hypothesized to weaken the bond between vWF and one of its toxic snake-venom ligands, the C-type lectin-like protein botrocetin. Our results provide the first example of rapid adaptive evolution in any venom-targeted molecule, and they support the notion that an evolutionary arms race might be driving the rapid evolution of snake venoms. However, in the arms race implied by our results, venomous snakes are prey, and their venom has a correspondingly defensive function in addition to its usual trophic role.

  10. Prevalence of and risk factors associated with the presence of Sarcocystis neurona sporocysts in opossum (Didelphis virginiana) from Michigan: a retrospective study.

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    Elsheikha, Hany M; Murphy, Alice J; Mansfield, Linda S

    2004-11-10

    From April 1996 to December 2002 the prevalence of Sarcocystis neurona sporocysts in North American opossum (Didelphis virginiana) in Southern Michigan was estimated. Sporocysts of S. neurona were found in intestinal scrapings from 31 (15%) of 206 examined opossum. The frequency of infection was higher in adult animals (26/206; 12.6%) and females (19/206; 9.2%) than in juveniles (5/206; 2.4%) and males (12/206; 5.8%). Also, prevalence of S. neurona sporocysts in opossums in relation to factors such as age, sex, season, body condition, presence of concomitant infection, and presence of young in the pouch of females was studied in detail over the course of the year, 2002. Univariate analyses identified the following factors as being associated with the presence of S. neurona sporocysts in opossums: (i) for age, adult (odd ratio [OR] = 2.074, P = 0.0005); (ii) for sex, female (OR = 7.016, P = 0.0119); (iii) for season, summer (OR = 7.917, P = 0.0032) and spring (OR = 4.071, P = 0.1063); (iv) for body condition, poor (OR = 3.50, P = 0.1200) and good (OR = 1.167, P = 0.8637); (v) for the presence of concomitant infection (OR = 23.056, P = 0001), and (vi) for the presence of young in the pouch of females (OR = 40.083, P = 0.0001). Multivariate logistic-regression analyses selected the following factors as being significantly associated with presence of S. neurona sporocysts in opossums: (i) for the presence of concomitant infection (OR = 8.722, P = 0.0160) and (ii) for the presence of young in the pouch of females (OR = 31.915, P = 0.0065). The prevalence of S. neurona sporocysts in D. virginiana suggests that this opossum may constitute an ample reservoir of infection to other animals in the northern United States.

  11. Phylogenetic relationships of Sarcocystis neurona of horses and opossums to other cyst-forming coccidia deduced from SSU rRNA gene sequences.

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    Elsheikha, Hany M; Lacher, David W; Mansfield, Linda S

    2005-11-01

    Phylogenetic analyses based on sequences of the nuclear-encoded small subunit rRNA (ssurRNA) gene were performed to examine the origin, phylogeny, and biogeographic relationships of Sarcocystis neurona isolates from opossums and horses from the State of Michigan, USA, in relation to other cyst-forming coccidia. A total of 31 taxa representing all recognized subfamilies and genera of Sarcocystidae were included in the analyses with clonal isolates of two opossum and two horse S. neurona. Phylogenies obtained by the four tree-building methods were consistent with the classical taxonomy based on morphological criteria. The "isosporid" coccidia Neospora, Toxoplasma, Besnoitia, Isospora lacking stieda bodies, and Hyaloklossia formed a sister group to the Sarcocystis spp. Sarcocystis species were divided into three main lineages; S. neurona isolates were located in the second lineage and clustered with S. mucosa, S. dispersa, S. lacertae, S. rodentifelis, S. muris, and Frenkelia spp. Alignment of S. neurona SSU rRNA gene sequences of Michigan opossum isolates (MIOP5, MIOP20) and a S. neurona Michigan horse isolate (MIH8) showed 100% identity. These Michigan isolates differed in 2/1085 bp (0.2%) from a Kentucky S. neurona horse isolate (SN5). Additionally, S. neurona isolates from horses and opossums were identical based on the ultrastructural features and PCR-RFLP analyses thus forming a phylogenetically indistinct group in these regions. These findings revealed the concordance between the morphological and molecular data and confirmed that S. neurona from opossums and horses originated from the same phylogenetic origin.

  12. The importance of the opossum (Didelphis albiventris as a reservoir for Trypanosoma cruzi in Bambuí, Minas Gerais state

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    Alexandre José Fernandes

    1991-03-01

    Full Text Available In a survey realized on the sylvatic and peridomestic environment at Bambuí county, Minas Gerais State, 44 (37.9% out of 116 opossums (Didelphis albiventris captured were found to be naturally infected with Trypanosoma cruzi. One handred and forty three parasite samples were obtanied from 43 infected opossums using simultaneously hemoculture, xenodiagnosis (Triatoma infestans, Panstrongylus megistus and Rhodnius neglectus and examination of anal glands contents. The parasite samples were characterized according to six isoenzyme patterns. All samples, independently of the method of isolation, presented an isoenzyme pattern similar to the standard T. cruzi Z1, showing that either xenodiagnosis or hemoculture can used without selecting parasite subpopulation from naturally infected opossums. Preveous isoenzyme patterns reported for human T.cruzi isolates from same region were completely different. This isoenzyme dissimilarity between sylvatic and domiciliar environments suggests the existence of two independent T. cruzi transmission cycles in Bambuí. The epidemiological implicatinos of these results are discussed.

  13. Scanning Electron Microscopic Structure of the Lingual Papillae of the Common Opossum (Didelphis marsupialis)

    Science.gov (United States)

    Okada, Shigenori; Schraufnagel, Dean E.

    2005-08-01

    The mammalian tongue has evolved for specialized functions in different species. The structure of its papillae tells about the animal's diet, habit, and taxonomy. The opossum has four kinds of lingual papillae (filiform, conical, fungiform, vallate). Scanning electron microscopy of the external features, connective tissue cores, and corrosion casts of the microvasculature show the filiform papillae have a spearhead-like main process and spiny accessory processes around the apical part of the main process. The shape and number of both processes depend on their position on the tongue. On the apex, the main processes have shovel-like capillary networks and the accessory processes have small conical networks. On the lingual radix, the processes have small capillary loops. In the patch region, conical papillae have capillaries arranged as a full sail curving posteriorly. The fungiform papillae are scattered among the filiform papillae and have capillary baskets beneath each taste bud. Giant fungiform papillae on the tongue tip are three to four times larger than the ones on the lingual body. Capillaries of giant papillae form a fan-shaped network. The opossum has three vallate papillae arranged in a triangle. Their tops have secondary capillary loops but not their lateral surfaces. Mucosal folds on the posterolateral border have irregular, fingerlike projections with cylindrical capillary networks. These findings and the structure of the rest of the masticatory apparatus suggest the lingual papillae of opossum have kept their ancestral carnivorous features but also developed the herbivore characteristics of other marsupials.

  14. Short-tailed shrews: Toxicity and residue relationships of DDT, dieldrin, and endrin

    Science.gov (United States)

    Blus, L.J.

    1978-01-01

    Experiments involving dietary toxicity and residue relationships of DDT, dieldrin, and endrin were conducted with short-tailed shrews. Dietary concentrations of DDT dissolved in vegetable oils were usually more toxic than diets containing comparable amounts of powdered DDT. Younger shrews, particularly females, were more tolerant of powdered DDT than older animals; yet, there were no conspicuous age differences in toxicity of DDT dissolved in oils. In comparison to other mammals, short-tailed shrews are not unusually sensitive to DDT, dieldrin, or endrin on the basis of two-week feeding tests. The influence of age and sex on toxicity of DDT, endrin, and dieldrin was sometimes more important than body weight. Of those shrews of the same age and sex that were fed the same dietary dosage, heavier shrews were more tolerant than lighter individuals; and, heavier shrews tended to lose a greater percentage of body weight before death. There was a range of 15 to 105 DDT equivalents in brains of shrews dying on dietary dosages of DDT. Six shrews fed a high level of DDT seemed to have unusual metabolite capabilities and died with apparent lethal levels of DDD in their brains. Levels of dieldrin in brains of shrews that died on a dietary dosage of dieldrin ranged from 3.7 to 12.6 ppm. In the rates of gain and loss experiments where shrews were given diets containing 400 ppm DDT or 50 ppm dieldrin up to 17 days, high residues were noted in tissues of shrews after two weeks on a contaminated diet and a few died at that time. After shrews were placed on clean food, it was determined that >50% of the dieldrin residues in carcass and brain were lost in 50% of residues of DDT and metabolites in brains after 2 weeks on clean food; males lost nearly 50% of residues in carcasses after two weeks on clean food compared with a loss of only 11% in females.

  15. Anatomical and radiographic study of the white-eared opossum (Didelphis albiventris skull1

    Directory of Open Access Journals (Sweden)

    Bruno C. Schimming

    Full Text Available ABSTRACT: This study was made to investigate the anatomical features of the white-eared opossum skull, by osteology and radiographic anatomy. For this, five animals were used without sexual distinction. The skull was examined by radiographic and macroscopic characteristics. The skulls were then subjected to maceration. The skull was described macroscopically according to standard views, i.e. dorsal and caudal, lateral, ventral, and midsagittal. The skull can be divided into facial (viscerocranium and cranial (neurocranium regions. The facial region was elongated and more developed than neurocranium. The supraorbital foramen was absent. The tympanic bulla is not well developed. The zygomatic arch was formed by zygomatic process of the temporal bone, zygomatic process of the maxilla, and temporal process of the zygomatic bone. There was no significant difference between bones found in this study when compared with those described for others mammals. These findings may contribute to the better understanding of the anatomy and biology of the white-eared opossum.

  16. Prevalence of agglutinating antibodies to Toxoplasma gondii in striped skunks (Mephitis mephitis), opossums (Didelphis virginiana), and raccoons (Procyon lotor) from Connecticut

    OpenAIRE

    Mitchell, S. M.; Richardson, D. J.; Lindsay, D. S.

    2006-01-01

    The prevalence of agglutinating antibodies to Toxoplasma gondii was examined in striped skunks (Mephitis mephitis), opossums (Didelphis virginiana), and raccoons (Procyon lotor) from 8 cities in Connecticut. Ten (42%) of the 24 striped skunks, 2 of 7 (29%) opossums, and 12 of 12 (100%) raccoons were positive at dilutions of 1:50 or greater. These results suggest that T. gondii is prevalent in the environment, or prey items, or both, of these omnivores in Connecticut.

  17. Prevalence of agglutinating antibodies to Toxoplasma gondii in striped skunks (Mephitis mephitis), opossums (Didelphis virginiana), and raccoons (Procyon lotor) from Connecticut.

    Science.gov (United States)

    Mitchell, Sheila M; Richardson, Dennis J; Lindsay, David S

    2006-06-01

    The prevalence of agglutinating antibodies to Toxoplasma gondii was examined in striped skunks (Mephitis mephitis), opossums (Didelphis virginiana), and raccoons (Procyon lotor) from 8 cities in Connecticut. Ten (42%) of the 24 striped skunks, 2 of 7 (29%) opossums, and 12 of 12 (100%) raccoons were positive at dilutions of 1:50 or greater. These results suggest that T. gondii is prevalent in the environment, or prey items, or both, of these omnivores in Connecticut.

  18. Cladistic analysis of olfactory and vomeronasal systems.

    Science.gov (United States)

    Ubeda-Bañon, Isabel; Pro-Sistiaga, Palma; Mohedano-Moriano, Alicia; Saiz-Sanchez, Daniel; de la Rosa-Prieto, Carlos; Gutierrez-Castellanos, Nicolás; Lanuza, Enrique; Martinez-Garcia, Fernando; Martinez-Marcos, Alino

    2011-01-01

    Most tetrapods possess two nasal organs for detecting chemicals in their environment, which are the sensory detectors of the olfactory and vomeronasal systems. The seventies' view that the olfactory system was only devoted to sense volatiles, whereas the vomeronasal system was exclusively specialized for pheromone detection was challenged by accumulating data showing deep anatomical and functional interrelationships between both systems. In addition, the assumption that the vomeronasal system appeared as an adaptation to terrestrial life is being questioned as well. The aim of the present work is to use a comparative strategy to gain insight in our understanding of the evolution of chemical "cortex." We have analyzed the organization of the olfactory and vomeronasal cortices of reptiles, marsupials, and placental mammals and we have compared our findings with data from other taxa in order to better understand the evolutionary history of the nasal sensory systems in vertebrates. The olfactory and vomeronsasal cortices have been re-investigated in garter snakes (Thamnophis sirtalis), short-tailed opossums (Monodelphis domestica), and rats (Rattus norvegicus) by tracing the efferents of the main and accessory olfactory bulbs using injections of neuroanatomical anterograde tracers (dextran-amines). In snakes, the medial olfactory tract is quite evident, whereas the main vomeronasal-recipient structure, the nucleus sphaericus is a folded cortical-like structure, located at the caudal edge of the amygdala. In marsupials, which are acallosal mammals, the rhinal fissure is relatively dorsal and the olfactory and vomeronasal cortices relatively expanded. Placental mammals, like marsupials, show partially overlapping olfactory and vomeronasal projections in the rostral basal telencephalon. These data raise the interesting question of how the telencephalon has been re-organized in different groups according to the biological relevance of chemical senses.

  19. Breeding short-tailed shearwaters buffer local environmental variability in south-eastern Australia by foraging in Antarctic waters.

    Science.gov (United States)

    Berlincourt, Maud; Arnould, John P Y

    2015-01-01

    Establishing patterns of movements of free-ranging animals in marine ecosystems is crucial for a better understanding of their feeding ecology, life history traits and conservation. As central place foragers, the habitat use of nesting seabirds is heavily influenced by the resources available within their foraging range. We tested the prediction that during years with lower resource availability, short-tailed shearwaters (Puffinus tenuirostris) provisioning chicks should increase their foraging effort, by extending their foraging range and/or duration, both when foraging in neritic (short trips) and distant oceanic waters (long trips). Using both GPS and geolocation data-loggers, at-sea movements and habitat use were investigated over three breeding seasons (2012-14) at two colonies in southeastern Australia. Most individuals performed daily short foraging trips over the study period and inter-annual variations observed in foraging parameters where mainly due to few individuals from Griffith Island, performing 2-day trips in 2014. When performing long foraging trips, this study showed that individuals from both colonies exploited similar zones in the Southern Ocean. The results of this study suggest that individuals could increase their foraging range while exploiting distant feeding zones, which could indicate that short-tailed shearwaters forage in Antarctic waters not only to maintain their body condition but may also do so to buffer against local environmental stochasticity. Lower breeding performances were associated with longer foraging trips to distant oceanic waters in 2013 and 2014 indicating they could mediate reductions in food availability around the breeding colonies by extending their foraging range in the Southern Ocean. This study highlights the importance of foraging flexibility as a fundamental aspect of life history in coastal/pelagic marine central place foragers living in highly variable environments and how these foraging strategies are use to

  20. Probing the density tail of radioactive nuclei with antiprotons

    CERN Document Server

    Obertelli, Alexandre; Uesaka, Tomohiro; Corsi, Anna; Pollacco, Emmanuel; Flavigny, Freddy

    2017-01-01

    We propose an experiment to determine the proton and neutron content of the radial density tail in short-lived nuclei. The objectives are to (i) to evidence new proton and neutron halos, (ii) to understand the development of neutron skins in medium-mass nuclei, (iii) to provide a new observable that characterises the density tail of short-lived nuclei.

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

    Science.gov (United States)

    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.

  2. Developmental plasticity of ascending spinal axons studies using the North American opossum, Didelphis virginiana.

    Science.gov (United States)

    Terman, J R; Wang, X M; Martin, G F

    1999-01-11

    The objectives of the present study were to determine if axons of all ascending tracts grow through the lesion after transection of the thoracic spinal cord during development in the North American opossum, and if so, whether they reach regions of the brain they normally innervate. Opossum pups were subjected to transection of the mid-thoracic cord at PD5, PD8, PD12, PD20, or PD26 and injections of Fast Blue (FB) into the lower thoracic or upper lumbar cord 30-40 days or 6 months later. In the PD5 transected cases, labeled axons were present in all of the supraspinal areas labeled by comparable injections in unlesioned, age-matched controls. In the experimental cases, however, labeled axons appeared to be fewer in number and in some areas more restricted in location than in the controls. When lesions were made at PD8, labeled axons were present in the brain of animals allowed to survive 30-40 days prior to FB injections but they were not observed in those allowed to survive 6 months. When lesions were made at PD12 or later, labeled axons were never found rostral to the lesion. It appears, therefore, that axons of all ascending spinal pathways grow though the lesion after transection of the thoracic cord in developing opossums and that they innervate appropriate areas of the brain. Interestingly, the critical period for such growth is shorter than that for most descending axons, suggesting that factors which influence loss of developmental plasticity are not the same for all axons.

  3. Urinary bladder incarceration and infarction by an intra-abdominal fat pad in a Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    De Voe, Ryan S; Spaulding, Kathy A; Rotstein, Jack; Rotstein, David S

    2004-01-01

    A 2.5-year-old, female opossum had acute stranguria. Based on radiography and ultrasonographic examination a cystic structure was identified in the caudal abdomen associated with bilateral hydroureter and hydronephrosis. This structure contained a neutrophilic fluid, determined to be urine. There was a neutrophilic leukocytosis. Serum chemistry values were within normal limits. The opossum was euthanized. An intra-abdominal fat pad incarceration of the urinary bladder above the trigone was present, resulting in complete obstruction of the urinary bladder and partial obstruction of the ureters. Vessels to the bladder were involved in the incarceration which resulted in vascular compromise and infarction of the bladder. Mild to moderate hydroureter and hydronephrosis were present.

  4. Expression, purification and characterization of the recombinant chimeric IgE Fc-fragment opossum-human-opossum (OSO), an active immunotherapeutic vaccine component.

    Science.gov (United States)

    Xu, Bingze; Lundgren, Mats; Magnusson, Ann-Christine; Fuentes, Alexis

    2010-11-01

    The active vaccine component recombinant chimeric IgE Fc-fragment opossum-human-opossum (OSO) has been expressed in CHO-K1 cells. It contains two identical polypeptide chains with 338 amino acid residues in each chain connected by two disulfide bridges. The cell lines were adapted to suspension culture in a serum-free medium. An expression level of 60 mg/L was obtained after 8 days in a shaking flask at a temperature of 31.5 degrees C. The OSO protein has been purified to homogeneity by a combination of three chromatographic steps. Virus inactivation and reduction by solvent detergent treatment and nano-filtration were included in the process. The residual host cell protein content was less than 50 ng/mg OSO as analyzed by ELISA. Purity was analyzed by SDS-PAGE under reducing and non-reducing conditions and was estimated by densitometry to be above 99.0%. The dimer content was less than 0.1% as estimated by analytical size exclusion chromatography. The molecular mass, as estimated by SDS-PAGE, is 90 kDa. A value of around 74 kDa was calculated from its amino acid composition. This indicates that the protein is heavily glycosylated containing around 18% carbohydrate. Isoelectric focusing in polyacrylamide gel disclosed a ladder type band pattern with pI values in the pH-range 7.0-8.3, indicating a variation in the sialic acid content. The OSO protein is not stable at temperatures above 40 degrees C and at pH values below 4 indicating that virus inactivation by incubating the protein solution at higher temperature or at lower pH is not possible. Copyright 2010 Elsevier Inc. All rights reserved.

  5. Femoral loading mechanics in the Virginia opossum, Didelphis virginiana: torsion and mediolateral bending in mammalian locomotion.

    Science.gov (United States)

    Gosnell, W Casey; Butcher, Michael T; Maie, Takashi; Blob, Richard W

    2011-10-15

    Studies of limb bone loading in terrestrial mammals have typically found anteroposterior bending to be the primary loading regime, with torsion contributing minimally. However, previous studies have focused on large, cursorial eutherian species in which the limbs are held essentially upright. Recent in vivo strain data from the Virginia opossum (Didelphis virginiana), a marsupial that uses a crouched rather than an upright limb posture, have indicated that its femur experiences appreciable torsion during locomotion as well as strong mediolateral bending. The elevated femoral torsion and strong mediolateral bending observed in D. virginiana might result from external forces such as a medial inclination of the ground reaction force (GRF), internal forces deriving from a crouched limb posture, or a combination of these factors. To evaluate the mechanism underlying the loading regime of opossum femora, we filmed D. virginiana running over a force platform, allowing us to measure the magnitude of the GRF and its three-dimensional orientation relative to the limb, facilitating estimates of limb bone stresses. This three-dimensional analysis also allows evaluations of muscular forces, particularly those of hip adductor muscles, in the appropriate anatomical plane to a greater degree than previous two-dimensional analyses. At peak GRF and stress magnitudes, the GRF is oriented nearly vertically, inducing a strong abductor moment at the hip that is countered by adductor muscles on the medial aspect of the femur that place this surface in compression and induce mediolateral bending, corroborating and explaining loading patterns that were identified in strain analyses. The crouched orientation of the femur during stance in opossums also contributes to levels of femoral torsion as high as those seen in many reptilian taxa. Femoral safety factors were as high as those of non-avian reptiles and greater than those of upright, cursorial mammals, primarily because the load

  6. Risk factors associated with the presence of Sarcocystis neurona sporocysts in opossums (Didelphis virginiana).

    Science.gov (United States)

    Rickard, L G; Black, S S; Rashmir-Raven, A; Hurst, G; Dubey, J P

    2001-12-13

    Sarcocystis neurona is the most important cause of equine protozoal myeloencephalitis (EPM) in horse in the Americas. The only known definitive host for this parasite in the United States is the opossum (Didelphis virginiana); however, despite the importance of the disease, the epidemiology of the parasite in the definitive host is poorly understood. To begin addressing these data gaps, potential risk factors were evaluated for their association with the presence of sporocysts of S. neurona in opossums live-trapped in March 1999 and November 1999 to May 2000. Sporocysts of S. neurona were found in 19 of the 72 animals examined. Potential risk factors evaluated were locality, trap date, age, gender, the presence of young in the pouch of females, and body condition score. Variables that were associated with the presence of S. neurona sporocysts were used in logistic regression analysis. Of the factors examined, season and body condition score were associated with increased odds of an animal harboring sporocysts.

  7. Light and electron microscopic features of eperythrozoon-like parasites in a North American opossum (Didelphis virginiana).

    Science.gov (United States)

    Messick, J B; Berent, L M; Ehrhart, E J; Wasmer, C C

    2000-06-01

    Epierythrocytic parasites associated with a severe anemic episode have not been previously reported in the opossum. A Wright-Giemsa-stained peripheral blood smear from an anemic North American opossum (Didelphis virginiana) revealed numerous organisms attached to red blood cells either singularly or in chains. Ring forms of the organism were common and could be found free in the plasma. Electron microscopy revealed that these organisms were attached to the intact plasma membrane in depressions on the surface of red blood cells. Delicate fibrils between the organism and adjacent membrane were observed. The organisms were round to oval with a diameter of 300-750 nm and were enclosed by a single limiting membrane. The light and electron microscopic features of these epierythrocytic organisms are similar to those reported for Eperythrozoon and Haemobartonella species.

  8. Rickettsia felis in cat fleas, Ctenocephalides felis parasitizing opossums, San Bernardino County, California.

    Science.gov (United States)

    Abramowicz, K F; Wekesa, J W; Nwadike, C N; Zambrano, M L; Karpathy, S E; Cecil, D; Burns, J; Hu, R; Eremeeva, M E

    2012-12-01

    Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however, no recent reports of flea-borne rickettsioses are known from adjacent San Bernardino County. Sixty-five opossums (Didelphis virginiana) were trapped in the suburban residential and industrial zones of the southwestern part of San Bernardino County in 2007. Sixty out of 65 opossums were infested with fleas, primarily cat fleas, Ctenocephalides felis (Bouché, 1835). The flea minimum infection rate with Rickettsia felis was 13.3% in pooled samples and the prevalence was 23.7% in single fleas, with two gltA genotypes detected. In spite of historic records of murine typhus in this area, no evidence for circulation of R. typhi in fleas was found during the present study. Factors contributing to the absence of R. typhi in these cat fleas in contrast to its presence in cat fleas from Orange and Los Angeles Counties are unknown and need to be investigated further in San Bernardino County. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

  9. Cone pigments in a North American marsupial, the opossum (Didelphis virginiana)

    OpenAIRE

    Jacobs, Gerald H.; Williams, Gary A.

    2010-01-01

    Only two of the four cone opsin gene families found in vertebrates are represented in contemporary eutherian and marsupial species. Recent genetic studies of two species of South American marsupial detected the presence of representatives from two of the classes of cone opsin genes and the structures of these genes predicted cone pigments with respective peaks in the ultraviolet and long-wavelength portions of the spectrum. The Virginia opossum (Didelphis virginiana), a profoundly nocturnal a...

  10. 50 CFR 32.62 - Tennessee.

    Science.gov (United States)

    2010-10-01

    ... hunting for raccoon and opossum from legal sunset to legal sunrise. C. Big Game Hunting. We allow hunting... do not open for spring squirrel hunting. C. Big Game Hunting. We allow the hunting of white-tailed... hours for raccoon and opossum are legal sunset to legal sunrise. C. Big Game Hunting. We allow hunting...

  11. Adult opossums (Didelphis virginiana) demonstrate near normal locomotion after spinal cord transection as neonates.

    Science.gov (United States)

    Wang, X M; Basso, D M; Terman, J R; Bresnahan, J C; Martin, G F

    1998-05-01

    When the thoracic spinal cord of the North American opossum (Didelphis virginiana) is transected on postnatal day (PD) 5, the site of injury becomes bridged by histologically recognizable spinal cord and axons which form major long tracts grow through the lesion. In the present study we asked whether opossums lesioned on PD5 have normal use of the hindlimbs as adults and, if so, whether that use is dependent upon axons which grow through the lesion site. The thoracic spinal cord was transected on PD5 and 6 months later, hindlimb function was evaluated using the Basso, Beattie, and Bresnahan (BBB) locomotor scale. All animals supported their weight with the hindlimbs and used their hindlimbs normally during overground locomotion. In some cases, the spinal cord was retransected at the original lesion site or just caudal to it 6 months after the original transection and paralysis of the hindlimbs ensued. Surprisingly, however, these animals gradually recovered some ability to support their weight and to step with the hindlimbs. Similar recovery was not seen in animals transected only as adults. In order to verify that descending axons which grew through the lesion during development were still present in the adult animal, opossums subjected to transection of the thoracic cord on PD5 were reoperated and Fast blue was injected several segments caudal to the lesion. In all cases, neurons were labeled rostral to the lesion in each of the spinal and supraspinal nuclei labeled by comparable injections in unlesioned, age-matched controls. The results of orthograde tracing studies indicated that axons which grew through the lesion innervated areas that were appropriate for them. Copyright 1998 Academic Press.

  12. Genomic imprinting of IGF2 in marsupials is methylation dependent

    Directory of Open Access Journals (Sweden)

    Imumorin Ikhide

    2008-05-01

    Full Text Available Abstract Background- Parent-specific methylation of specific CpG residues is critical to imprinting in eutherian mammals, but its importance to imprinting in marsupials and, thus, the evolutionary origins of the imprinting mechanism have been the subject of controversy. This has been particularly true for the imprinted Insulin-like Growth Factor II (IGF2, a key regulator of embryonic growth in vertebrates and a focal point of the selective forces leading to genomic imprinting. The presence of the essential imprinting effector, DNMT3L, in marsupial genomes and the demonstration of a differentially methylated region (DMR in the retrotransposon-derived imprinted gene, PEG10, in tammar wallaby argue for a role for methylation in imprinting, but several studies have found no evidence of parent-specific methylation at other imprinted loci in marsupials. Results- We performed the most extensive search to date for allele-specific patterns of CpG methylation within CpG isochores or CpG enriched segments across a 22 kilobase region surrounding the IGF2 gene in the South American opossum Monodelphis domestica. We identified a previously unknown 5'-untranslated exon for opossum IGF2, which is flanked by sequences defining a putative neonatal promoter, a DMR and an active Matrix Attachment Region (MAR. Demethylation of this DMR in opossum neonatal fibroblasts results in abherrant biallelic expression of IGF2. Conclusion- The demonstration of a DMR and an active MAR in the 5' flank of opossum IGF2 mirrors the regulatory features of the 5' flank of Igf2 in mice. However, demethylation induced activation of the maternal allele of IGF2 in opossum differs from the demethylation induced repression of the paternal Igf2 allele in mice. While it can now be concluded that parent-specific DNA methylation is an epigentic mark common to Marsupialia and Eutheria, the molecular mechanisms of transcriptional silencing at imprinted loci have clearly evolved along independent

  13. Immunohistochemical localization of gastrin-releasing peptide, neuronal nitric oxide synthase and neurone-specific enolase in the uterus of the North American opossum, Didelphis virginiana.

    Science.gov (United States)

    Kumano, A; Sasaki, M; Budipitojo, T; Kitamura, N; Krause, W J; Yamada, J

    2005-08-01

    The present study has demonstrated the immunohistochemical localization of gastrin-releasing peptide (GRP), neuronal nitric oxide synthase (nNOS) and neurone-specific enolase (NSE) in the uterus of the North American opossum. Although the presence of GRP, nNOS and NSE has been reported recently in the uterus of eutherian species this is the first description of these peptides in a metatherian species. Metatherian mammals are of interest because in these species it is the prolonged lactation phase of development that is the period of primary reproductive investment rather than intrauterine development as is true of eutherian mammals. The opossum, like other marsupial species, has a very abbreviated gestation period which in Didelphis lasts only 12.5 days. GRP was localized in the cytoplasm of cells forming the surface lining epithelium and the glandular epithelium of the opossum endometrium late in pregnancy, at 11.5 days of gestation. Likewise, immunoreactivities of nNOS and NSE were found primarily within the epithelial cells of the endometrium at 11.5 days of gestation. As these peptides and enzymes appear primarily at the time of establishment of the yolk sac placenta (between day 10 and day 12.5 gestation), the present results strongly suggest that these factors may play a fundamental role in the placentation of the opossum.

  14. THE ELECTROMAGNETIC MODEL OF SHORT GRBs, THE NATURE OF PROMPT TAILS, SUPERNOVA-LESS LONG GRBs, AND HIGHLY EFFICIENT EPISODIC ACCRETION

    Energy Technology Data Exchange (ETDEWEB)

    Lyutikov, Maxim [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907-2036 (United States)

    2013-05-01

    Many short gamma-ray bursts (GRBs) show prompt tails lasting up to hundreds of seconds that can be energetically dominant over the initial sub-second spike. In this paper we develop an electromagnetic model of short GRBs that explains the two stages of the energy release, the prompt spike and the prompt tail. The key ingredient of the model is the recent discovery that an isolated black hole can keep its open magnetic flux for times much longer than the collapse time and thus can spin down electromagnetically, driving the relativistic wind. First, the merger is preceded by an electromagnetic precursor wind with total power L{sub p} Almost-Equal-To (((GM{sub NS}){sup 3}B{sub NS}{sup 2})/c{sup 5}R){proportional_to}(-t){sup - Vulgar-Fraction-One-Quarter }, reaching 3 Multiplication-Sign 10{sup 44} erg s{sup -1} for typical neutron star masses of 1.4 M{sub Sun} and magnetic fields B {approx} 10{sup 12} G. If a fraction of this power is converted into pulsar-like coherent radio emission, this may produce an observable radio burst of a few milliseconds (like the Lorimer burst). At the active stage of the merger, two neutron stars produce a black hole surrounded by an accretion torus in which the magnetic field is amplified to {approx}10{sup 15} G. This magnetic field extracts the rotational energy of the black hole and drives an axially collimated electromagnetic wind that may carry of the order of 10{sup 50} erg, limited by the accretion time of the torus, a few hundred milliseconds. For observers nearly aligned with the orbital normal this is seen as a classical short GRB. After the accretion of the torus, the isolated black hole keeps the open magnetic flux and drives the equatorially (not axially) collimated outflow, which is seen by an observer at intermediate polar angles as a prompt tail. The tail carries more energy than the prompt spike, but its emission is de-boosted for observers along the orbital normal. Observers in the equatorial plane miss the prompt spike

  15. West Nile virus isolated from a Virginia opossum (Didelphis virginiana) in northwestern Missouri, USA, 2012.

    Science.gov (United States)

    Bosco-Lauth, Angela; Harmon, Jessica R; Lash, R Ryan; Weiss, Sonja; Langevin, Stanley; Savage, Harry M; Godsey, Marvin S; Burkhalter, Kristen; Root, J Jeffrey; Gidlewski, Thomas; Nicholson, William L; Brault, Aaron C; Komar, Nicholas

    2014-10-01

    We describe the isolation of West Nile virus (WNV; Flaviviridae, Flavivirus) from blood of a Virginia opossum (Didelphis virginiana) collected in northwestern Missouri, USA in August 2012. Sequencing determined that the virus was related to lineage 1a WNV02 strains. We discuss the role of wildlife in WNV disease epidemiology.

  16. Phylogenetic differences of mammalian basal metabolic rate are not explained by mitochondrial basal proton leak.

    Science.gov (United States)

    Polymeropoulos, E T; Heldmaier, G; Frappell, P B; McAllan, B M; Withers, K W; Klingenspor, M; White, C R; Jastroch, M

    2012-01-07

    Metabolic rates of mammals presumably increased during the evolution of endothermy, but molecular and cellular mechanisms underlying basal metabolic rate (BMR) are still not understood. It has been established that mitochondrial basal proton leak contributes significantly to BMR. Comparative studies among a diversity of eutherian mammals showed that BMR correlates with body mass and proton leak. Here, we studied BMR and mitochondrial basal proton leak in liver of various marsupial species. Surprisingly, we found that the mitochondrial proton leak was greater in marsupials than in eutherians, although marsupials have lower BMRs. To verify our finding, we kept similar-sized individuals of a marsupial opossum (Monodelphis domestica) and a eutherian rodent (Mesocricetus auratus) species under identical conditions, and directly compared BMR and basal proton leak. We confirmed an approximately 40 per cent lower mass specific BMR in the opossum although its proton leak was significantly higher (approx. 60%). We demonstrate that the increase in BMR during eutherian evolution is not based on a general increase in the mitochondrial proton leak, although there is a similar allometric relationship of proton leak and BMR within mammalian groups. The difference in proton leak between endothermic groups may assist in elucidating distinct metabolic and habitat requirements that have evolved during mammalian divergence.

  17. First molecular evidence of Toxoplasma gondii in opossums (Didelphis virginiana) from Yucatan, Mexico

    OpenAIRE

    Torres-Castro, M.; Noh-Pech, H.; Puerto-Hern?ndez, R.; Reyes-Hern?ndez, B.; Panti-May, A.; Hern?ndez-Betancourt, S.; Yeh-Gorocica, A.; Gonz?lez-Herrera, L.; Zavala-Castro, J.; Puerto, F.I.

    2016-01-01

    Toxoplasma gondii is an obligate intracellular parasite recognized as a causal agent of toxoplasmosis; zoonotic disease endemic in many countries worldwide, including Mexico. Different species of animals participate in the wild cycle infection, including opossums of the species Didelphis virginiana. Thirteen D. virginiana were captured in Yucatan, Mexico. Detection of T. gondii was achieved by Polymerase Chain Reaction, which determined an infection of 76.9% (10/13) in brains. Positive amplic...

  18. Spontaneous squamous cell carcinoma of the tongue and multiple bronchioloalveolar carcinomas in a Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    Kim, D Y; Mitchell, M A; De las Heras, M; Taylor, H W; Cho, D-Y

    2002-01-01

    Two primary tumours, squamous cell carcinoma of the tongue and multiple bronchioloalveolar carcinomas, were diagnosed in a Virginia opossum (Didelphis virginiana). Two oral masses were located in the right ventrolateral surface of the tongue, near the frenulum, and the lungs contained multiple, widely distributed, nodular masses. Microscopically, the oral masses were composed of invasive cords of pleomorphic, polyhedral cells, typical of squamous cells. The multiple pulmonary masses consisted of non-ciliated, cuboidal, columnar, or occasionally polyhedral cells arranged in an alveolar pattern with multifocal areas of necrosis. This is the first report of spontaneous oropharyngeal squamous cell carcinoma in the Virginia opossum. However, multiple pulmonary adenomas have been reported previously in this species, the lesions being similar to those in sheep pulmonary adenomatosis (jaagsiekte). In the present study, immunohistochemical examination of the pulmonary tumours with a rabbit polyclonal antiserum to jaagsiekte retroviral capsid protein proved negative. Copyright Harcourt Publishers Ltd.

  19. Physical and chemical effects of ingested plastic debris on short-tailed shearwaters, Puffinus tenuirostris, in the North Pacific Ocean

    OpenAIRE

    Yamashita, Rei; Takada, Hideshige; Fukuwaka, Masa-aki; Watanuki, Yutaka

    2011-01-01

    We investigated the plastics ingested by short-tailed shearwaters, Puffinus tenuirostris, that were accidentally caught during experimental fishing in the North Pacific Ocean in 2003 and 2005. The mean mass of plastics found in the stomach was 0.23 g per bird (n = 99). Plastic mass did not correlate with body weight. Total PCB (sum of 24 congeners) concentrations in the abdominal adipose tissue of 12 birds ranged from 45 to 529 ng/g-lipid. Although total PCBs or higher-chlorinated congeners, ...

  20. Fatal attraction of short-tailed shearwaters to artificial lights.

    Directory of Open Access Journals (Sweden)

    Airam Rodríguez

    Full Text Available Light pollution is increasing around the world and altering natural nightscapes with potential ecological and evolutionary consequences. A severe ecological perturbation caused by artificial lights is mass mortalities of organisms, including seabird fledglings that are attracted to lights at night on their first flights to the sea. Here, we report on the number of fledging short-tailed shearwaters Ardenna tenuirostris found grounded in evening and morning rescue patrols conducted at Phillip Island, Australia, during a 15-year period (1999-2013. We assessed factors affecting numbers of grounded birds and mortality including date, moon phase, wind direction and speed, number of visitors and holiday periods. We also tested experimentally if birds were attracted to lights by turning the lights off on a section of the road. Of 8871 fledglings found, 39% were dead or dying. This mortality rate was 4-8 times higher than reported elsewhere for other shearwater species, probably because searching for fledglings was part of our systematic rescue effort rather than the opportunistic rescue used elsewhere. Thus, it suggests that light-induced mortality of seabirds is usually underestimated. We rescued more birds (dead and alive in peak fledging, moonless and windy nights. Mortality increased through the fledging period, in the mornings and with increased traffic on holiday periods. Turning the road lights off decreased the number of grounded birds (dead and alive. While moon, wind and time are uncontrolled natural constraints, we demonstrated that reduction of light pollution and better traffic management can mitigate artificial light-induced mortality.

  1. Prevalence of antibodies to Trypanosoma cruzi, Toxoplasma gondii, Encephalitozoon cuniculi, Sarcocystis neurona, Besnoitia darlingi, and Neospora caninum in North American opossums, Didelphis virginiana, from southern Louisiana.

    Science.gov (United States)

    Houk, Alice E; Goodwin, David G; Zajac, Anne M; Barr, Stephen C; Dubey, J P; Lindsay, David S

    2010-12-01

    We examined the prevalence of antibodies to zoonotic protozoan parasites ( Trypanosoma cruzi, Toxoplasma gondii, and Encephalitozoon cuniculi) and protozoans of veterinary importance ( Neospora caninum, Sarcocystis neurona, and Besnoitia darlingi) in a population of North American opossums ( Didelphis virginiana) from Louisiana. Samples from 30 opossums were collected as part of a survey for T. cruzi in Louisiana. Frozen sera from these 30 opossums were examined using an indirect immunofluorescent antibody test (IFAT) against in vitro-produced antigenic stages of these protozoans. Additionally, 24 of the 30 samples were examined using hemoculture, and all 30 were examined in the modified direct agglutination test (MAT) for antibodies to To. gondii. The prevalences of reactive IFAT samples were as follows: 60% for T. cruzi, 27% for To. gondii, 23% for E. cuniculi, 17% for S. neurona, 47% for B. darlingi, and 0% for N. caninum. Hemoculture revealed that 16 (67%) of 24 samples were positive for T. cruzi, compared to 18 of 30 (60%) by IFAT. The sensitivity and specificity for the IFAT compared to hemoculture was 100% for each. The modified direct agglutination test revealed that 9 (30%) of the 30 samples from opossums had antibodies to To. gondii , compared to 8 (27%) using the IFAT. The sensitivity and specificity of the IFAT compared to the MAT was 100% and 72%, respectively.

  2. Making the most of RNA-seq: Pre-processing sequencing data with Opossum for reliable SNP variant detection [version 1; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Laura Oikkonen

    2017-01-01

    Full Text Available Identifying variants from RNA-seq (transcriptome sequencing data is a cost-effective and versatile alternative to whole-genome sequencing. However, current variant callers do not generally behave well with RNA-seq data due to reads encompassing intronic regions. We have developed a software programme called Opossum to address this problem. Opossum pre-processes RNA-seq reads prior to variant calling, and although it has been designed to work specifically with Platypus, it can be used equally well with other variant callers such as GATK HaplotypeCaller. In this work, we show that using Opossum in conjunction with either Platypus or GATK HaplotypeCaller maintains precision and improves the sensitivity for SNP detection compared to the GATK Best Practices pipeline. In addition, using it in combination with Platypus offers a substantial reduction in run times compared to the GATK pipeline so it is ideal when there are only limited time or computational resources available.

  3. Overview by Pioneer observations of the distant geomagnetic tail

    Energy Technology Data Exchange (ETDEWEB)

    Villante, U [L' Aquila Univ. (Italy). Istituto de Astrofisica

    1977-03-01

    Pioneer 7 and Pioneer 8 spacecraft provided the only direct observations of the geomagnetic tail at geocentric distances as large as 1000 Rsub(e) and 500 Rsub(e) respectively. The presence of a low density plasma flow in the region of expected tail and the intermittent and short duration character of the tail encounters suggested in the past a distant tail structure remarkably different from its near-earth and cislunar shape. However the recent discovery of the plasma mantle allows interpretation of the Pioneer observations in terms of a distant tail that possibly is still preserving most of its near-earth characteristics. In particular, the region of tail encounters and the magnitude and direction of the observed magnetic field might be consistent with a cylindrical tail with a modestly increased cross-section. Neutral sheet observations also appear to be consistent with the most recent bidimensional tail models. Finally, as in the cislunar region, the double peaked proton energy spectra can be interpreted in terms of a partial intermingling of plasma sheet and plasma mantle populations.

  4. Sarcocystis greineri n. sp. (Protozoa: Sarcocystidae) in the Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    Cheadle, M A

    2001-10-01

    Sarcocysts were found in the skeletal muscles of road-killed and live-trapped opossums collected in north central Florida. Sarcocysts were spindle-shaped and macroscopic and had an average measurement of 3.8 mm by 154.6 microm. Sarcocysts were only observed in skeletal muscle. Sarcocysts have invaginations throughout the sarcocyst wall, which is approximately 1 microm thick. Protrusions on the sarcocyst wall are stumpy and digitlike and contain fibrillar elements that extend from the interior portion of the cyst wall through the villi. A new name, Sarcocystis greineri, is proposed for this species.

  5. Dewatering tailings impoundments : interior drains

    International Nuclear Information System (INIS)

    Charlie, W.A.; Doehring, D.O.; Durnford, D.S.

    1984-01-01

    For the design of a new uranium tailings impoundment in the western United States, it was proposed that an interior drainage system be considered to economically and reliably minimize potential short- and long-term environmental impacts. The objectives were to decrease the effective hydraulic head on the clay liner, to dewater and stabilize the tailings, and to increase the amount of water recycled to the mill. In addition, desaturation of the impoundment would induce capillary pressure (negative porewater pressure), further reducing the potential movement of dissolved pollutants. This paper presents saturated and unsaturated seepage principles and reviews the concept, criteria and design of the various interior drainage systems considered

  6. Uranium mine tailings and obligations to future generations

    International Nuclear Information System (INIS)

    Brook, A.

    1980-01-01

    Low-level wastes from uranium mine/mill operations, because of their huge volume, are a serious problem, yet relatively little attention has been paid to them. Management of tailings piles and waste liquids in the short term is fairly effective. However these management techniques involve continuous, active treatment of the wastes, which may not continue after operations shut down, and rely on containment structures with a short effective life. Tailings can probably be rendered safe for future generations if sufficient resources are devoted to the task. The central moral question is whether we are obligated to assume the costs of tailings management, or whether it is permissible to pass them on to future generations. The basic moral principle that each person has the same value as any other implies that the generation that reaps the benefits of nuclear power must assume the costs of managing mine tailings and not discriminate in favour of one group of persons, our own generation. The argument that people who may exist in the future have intrinsically less value than people currently alive is not accepted by the author. The methodology for determining obligations to future generations which has been applied to mine/mill wastes could be applied to other nuclear issues, too. (LL)

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

    Science.gov (United States)

    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.

  8. A Descriptive Morphometric Approach of the Skull and Mandible of the Common Opossum (Didelphis Marsupialis Linnaeus, 1758 in the Caribbean and its Clinical Application during Regional Anaesthesia

    Directory of Open Access Journals (Sweden)

    Reda Mohamed

    2018-03-01

    Full Text Available The aim of this study was to determine the morphometric values of the skull and the mandible of the common opossum from the Caribbean island of Trinidad and Tobago. The skulls and mandibles were obtained from ten opossums captured for research purposes. The skulls and mandibles were prepared and cleaned using standard method. Some anatomical landmarks of the skulls and mandibles were identified and measured. The results were important for identification of the common opossum via comparison and discussion of our results with that of other marsupial species. Furthermore, the results had clinical importance with regard to regional nerve blocks of the infraorbital, inferior alveolar, and mental nerves for dental extraction and head surgery. This study concluded that by using the anatomical landmarks of the infraorbital and mental foramina it will be easier for the veterinarian surgeons during the application of local anesthetic agent for the infraorbital, inferior alveolar, and mental nerve blocks.

  9. Use of the space by the opossum Didelphis aurita Wied-Newied (Mammalia, Marsupialia in a mixed forest fragment of southern Brazil

    Directory of Open Access Journals (Sweden)

    Cáceres Nilton Carlos

    2003-01-01

    Full Text Available Use of the space by the opossum Didelphis aurita Wied-Newied, 1826 (Mammalia, Marsupialia in a mixed forest fragment of southern Brazil. The space use of the marsupial Didelphis aurita was studied in a forest fragment of southern Brazil from February 1995 to January 1996. The method used was the 'distribution utilization' in which each trap was set in 38 x 38 m quadrats. Captures of each marked individual in each point give information on its habitat use. Food availability was searched and compared to the habitat utilization and to the food consumption of opossums. Distribution patterns of captures (aggregated to random and spatial overlap between individuals were searched. Results showed aggregated distributions of individuals, particularly females, in the fragment. Females used exclusively the fragment during the drier season. Opossums tend to not choose the sites with highest food availability to establish home ranges. Spatial overlap was usually low between forest resident and neighbouring resident females, but much lower during the breeding season (only forest resident females in an apparently pattern of territoriality. Hence, core areas of females decreased in size during the breeding season. Males probably searched primarily for mates during the breeding season being less opportunistic than females in feeding habits, yet their space use did not correlate to food consumption.

  10. Natural infection of the opossum Didelphis albiventris (Marsupialia, Didelphidae with Leishmania donovani, in Brazil

    Directory of Open Access Journals (Sweden)

    Ítalo A. Sherlock

    1984-12-01

    Full Text Available An opossum, Didelphis albiventris, from Jacobina, bahia State, was found naturally infected with Leishmania donovani, being the first non-canid wild mammal to be detected with agent of kala-azar in the New World.Um gambá, Didelphis albiventris, de Jacobina, Bahia, foi encontrado com infecção natural pela Leishmania donovani, sendo o primeiro mamífero silvestre não-canídeo a ser achado com o agente do calazar nas Américas.

  11. Sarcocystis neurona infections in raccoons (Procyon lotor): evidence for natural infection with sarcocysts, transmission of infection to opossums (Didelphis virginiana), and experimental induction of neurologic disease in raccoons.

    Science.gov (United States)

    Dubey, J P; Saville, W J; Stanek, J F; Lindsay, D S; Rosenthal, B M; Oglesbee, M J; Rosypal, A C; Njoku, C J; Stich, R W; Kwok, O C; Shen, S K; Hamir, A N; Reed, S M

    2001-10-24

    Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease of horses in the Americas and Sarcocystis neurona is the most common etiologic agent. The distribution of S. neurona infections follows the geographical distributions of its definitive hosts, opossums (Didelphis virginiana, Didelphis albiventris). Recently, cats and skunks were reported as experimental and armadillos as natural intermediate hosts of S. neurona. In the present report, raccoons (Procyon lotor) were identified as a natural intermediate host of S. neurona. Two laboratory-raised opossums were found to shed S. neurona-like sporocysts after ingesting tongues of naturally-infected raccoons. Interferon-gamma gene knockout (KO) mice fed raccoon-opossum-derived sporocysts developed neurologic signs. S. neurona was identified immunohistochemically in tissues of KO mice fed sporocysts and the parasite was isolated in cell cultures inoculated with infected KO mouse tissues. The DNA obtained from the tongue of a naturally-infected raccoon, brains of KO mice that had neurological signs, and from the organisms recovered in cell cultures inoculated with brains of neurologic KO mice, corresponded to that of S. neurona. Two raccoons fed mature S. neurona sarcocysts did not shed sporocysts in their feces, indicating raccoons are not likely to be its definitive host. Two raccoons fed sporocysts from opossum feces developed clinical illness and S. neurona-associated encephalomyelitis was found in raccoons killed 14 and 22 days after feeding sporocysts; schizonts and merozoites were seen in encephalitic lesions.

  12. Ultraviolet radiation-induced histopathologic changes in the skin of the marsupial Monodelphis domestica. II. Quantitative studies of the photoreactivation of induced hyperplasia and sunburn cell formation

    International Nuclear Information System (INIS)

    Ley, R.D.; Applegate, L.A.

    1985-01-01

    Induction of sunburn cells (SBCs) and hyperplasia of the epidermis of the marsupial Monodelphis domestica by ultraviolet radiation (UVR) has been studied. A dose of 500 J/m2 (approximately 1 minimal erythemal dose) from an FS-40 sunlamp induced measurable numbers of SBCs with a peak number at 32-48 h post-UVR exposure of skin to photoreactivating light suppressed the induction of SBCs by approximately 75%. Pre-UVR exposure to photoreactivating light had no effect on the induction of SBCs. Induction of hyperplasia also was suppressed to a similar extent by post-UVR photoreactivation treatment. These studies identify pyrimidine dimers in DNA as the major photoproduct involved in the induction of SBCs and hyperplasia in M. domestica by UVR

  13. In vivo strains in the femur of the Virginia opossum (Didelphis virginiana) during terrestrial locomotion: testing hypotheses of evolutionary shifts in mammalian bone loading and design.

    Science.gov (United States)

    Butcher, Michael T; White, Bartholomew J; Hudzik, Nathan B; Gosnell, W Casey; Parrish, John H A; Blob, Richard W

    2011-08-01

    Terrestrial locomotion can impose substantial loads on vertebrate limbs. Previous studies have shown that limb bones from cursorial species of eutherian mammals experience high bending loads with minimal torsion, whereas the limb bones of non-avian reptiles (and amphibians) exhibit considerable torsion in addition to bending. It has been hypothesized that these differences in loading regime are related to the difference in limb posture between upright mammals and sprawling reptiles, and that the loading patterns observed in non-avian reptiles may be ancestral for tetrapod vertebrates. To evaluate whether non-cursorial mammals show loading patterns more similar to those of sprawling lineages, we measured in vivo strains in the femur during terrestrial locomotion of the Virginia opossum (Didelphis virginiana), a marsupial that uses more crouched limb posture than most mammals from which bone strains have been recorded, and which belongs to a clade phylogenetically between reptiles and the eutherian mammals studied previously. The presence of substantial torsion in the femur of opossums, similar to non-avian reptiles, would suggest that this loading regime likely reflects an ancestral condition for tetrapod limb bone design. Strain recordings indicate the presence of both bending and appreciable torsion (shear strain: 419.1 ± 212.8 με) in the opossum femur, with planar strain analyses showing neutral axis orientations that placed the lateral aspect of the femur in tension at the time of peak strains. Such mediolateral bending was unexpected for a mammal running with near-parasagittal limb kinematics. Shear strains were similar in magnitude to peak compressive axial strains, with opossum femora experiencing similar bending loads but higher levels of torsion compared with most previously studied mammals. Analyses of peak femoral strains led to estimated safety factor ranges of 5.1-7.2 in bending and 5.5-7.3 in torsion, somewhat higher than typical mammalian values

  14. Making the most of RNA-seq: Pre-processing sequencing data with Opossum for reliable SNP variant detection [version 2; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Laura Oikkonen

    2017-03-01

    Full Text Available Identifying variants from RNA-seq (transcriptome sequencing data is a cost-effective and versatile complement to whole-exome (WES and whole-genome sequencing (WGS analysis. RNA-seq (transcriptome sequencing is primarily considered a method of gene expression analysis but it can also be used to detect DNA variants in expressed regions of the genome. However, current variant callers do not generally behave well with RNA-seq data due to reads encompassing intronic regions. We have developed a software programme called Opossum to address this problem. Opossum pre-processes RNA-seq reads prior to variant calling, and although it has been designed to work specifically with Platypus, it can be used equally well with other variant callers such as GATK HaplotypeCaller. In this work, we show that using Opossum in conjunction with either Platypus or GATK HaplotypeCaller maintains precision and improves the sensitivity for SNP detection compared to the GATK Best Practices pipeline. In addition, using it in combination with Platypus offers a substantial reduction in run times compared to the GATK pipeline so it is ideal when there are only limited time or computational resources available.

  15. Trypanosoma cruzi infection in the opossum Didelphis marsupialis: absence of neonatal transmission and protection by maternal antibodies in experimental infections

    Directory of Open Access Journals (Sweden)

    Ana M. Jansen

    1994-03-01

    Full Text Available The high rate of natural Trypanosoma cruzi infection found in opossums does not always correlate with appreciable densities of local triatomid populations. One alternative method which might bypass the invertebrate vector is direct transmission from mother to offspring. This possibility was investigated in five T. cruzi infected females and their litters (24 young. The influence of maternal antibodies transferred via lactation, on the course of experimental infection, was also examined. Our results show that neonatal transmission is probably not responsible for the high rate of natural T. cruzi infection among opossums. In addition antibodies of maternal origin confer a partial protection to the young. This was demonstrated by the finding of a double prepatency period and 4,5 fold lower levels of circulating parasites, in experimentally infected pouch young from infected as compared to control uninfected mothes. On the other hand, the duration of patent parasitemia was twice as long as that observed in the control group.

  16. Tail Docking and Ear Cropping Dogs: Public Awareness and Perceptions.

    Science.gov (United States)

    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.

  17. Tail Docking and Ear Cropping Dogs: Public Awareness and Perceptions.

    Directory of Open Access Journals (Sweden)

    Katelyn E Mills

    Full Text Available 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.

  18. Didelphis marsupialis (common opossum): a potential reservoir host for zoonotic leishmaniasis in the metropolitan region of Belo Horizonte (Minas Gerais, Brazil)

    NARCIS (Netherlands)

    Schallig, Henk D. F. H.; da Silva, Eduardo S.; van der Meide, Wendy F.; Schoone, Gerard J.; Gontijo, Celia M. F.

    2007-01-01

    Identification of the zoonotic reservoir is important for leishmaniasis control program. A number of (wild) animal species may serve as reservoir hosts, including the opossum Didelphis marsupialis. A survey carried out in Didelphis specimens (n = 111) from the metropolitan region of Belo Horizonte,

  19. Regeneration of descending spinal axons after transection of the thoracic spinal cord during early development in the North American opossum, Didelphis virginiana.

    Science.gov (United States)

    Martin, G F; Terman, J R; Wang, X M

    2000-11-15

    Opossums are born in an immature, fetal-like state, making it possible to lesion their spinal cord early in development without intrauterine surgery. When the thoracic spinal cord of the North American opossum, Didelphis virginiana, is transected on postnatal day 5, and injections of Fast Blue (FB) are made caudal to the lesion site 30-40 days or 6 months later, neurons are labeled in all of the spinal and supraspinal areas that are labeled after comparable injections in age-matched, unlesioned controls. Double-labeling studies document that regeneration of cut axons contributes to growth of axons through the lesion site and behavioral studies show that animals lesioned on postnatal day 5 use their hindlimbs in normal appearing locomotion as adults. The critical period for developmental plasticity of descending spinal axons extends to postnatal day 26, although axons which grow through the lesion site become fewer in number and more restricted as to origin with increasing age. Animals lesioned between postnatal day 12 and 26 use the hindlimbs better than animals lesioned as adults, but hindlimb function is markedly abnormal and uncoordinated with that of the forelimbs. We conclude that restoration of anatomical continuity occurs after transection of the spinal cord in developing opossums, that descending axons grow through the lesion site, that regeneration of cut axons contributes to such growth, and that animals lesioned early enough in development have relatively normal motor function as adults.

  20. Tail posture predicts tail damage among weaned piglets

    NARCIS (Netherlands)

    Zonderland, J.J.; Riel, van J.W.; Bracke, M.B.M.; Kemp, B.; Hartog, den L.A.; Spoolder, H.A.M.

    2009-01-01

    Tail biting in pigs is a widespread behavioural vice with significant animal welfare and economic consequences. All too often, tail biting is not diagnosed nor dealt with until tail damage is present. To effectively reduce the negative effects of tail biting, it must be diagnosed in an early stage.

  1. The development of a testosterone stimulation test in the Virginia opossum (Didelphis virginiana) and its use in evaluating deslorelin contraception.

    Science.gov (United States)

    Johnston, S D; Camacho, F C; Carrillo, L; Guy, N; Govea, J; Martinez, O; Parãs, A; Lisle, A T; D'Occhio, M

    2008-01-01

    The aims of the present study were to examine the variability of testosterone secretion in the Virginia Opossum over a 24 h period and to develop a testosterone stimulation test that would provide an index of the prevailing testosterone biosynthetic capacity of the testes; the latter was used to clinically evaluate the efficacy of a gonadotrophin-releasing hormone agonist contraceptive. Sexually-mature captive opossums (n = 12) located in Africam Safari (Mexico) sampled every 12 h over 24 h consistently showed basal (<0.21 ng mL(-1)) blood testosterone concentrations. Intra-muscular injection of buserelin (2 microg mL(-1)) and human chorionic gonadotrophin (hCG; 1000 IU) resulted in an increase (P < 0.05) of plasma testosterone concentrations with maximal concentrations (3.9 ng mL(-1) and 5.8 ng mL(-1) respectively) occurring 120 min after injection. Plasma testosterone declined relatively rapidly to basal concentrations after 240 min with hCG but remained elevated after the same period of time with buserelin. Male opossums treated with (n = 6) and without (n = 6) a controlled-release deslorelin implant (Suprelorin; 4.7 mg deslorelin) were evaluated over a 10-week period for changes in testosterone secretion (hCG stimulation test) and sperm production (spermatorrhea). At the end of this period, the animals were hemi-castrated and their relative testicular quantitative histology compared. Testosterone concentration decreased over the course of the study in both treated and control animals (P < 0.0001) but there was no apparent effect of deslorelin on testosterone secretion, testicular histology (relative proportions of testicular cell types and seminiferous tubule diameter), or sperm production (presence of sperm in the cauda epididymis or urine).

  2. A retrotransposon insertion in the 5' regulatory domain of Ptf1a results in ectopic gene expression and multiple congenital defects in Danforth's short tail mouse.

    Directory of Open Access Journals (Sweden)

    Francesca Lugani

    Full Text Available Danforth's short tail mutant (Sd mouse, first described in 1930, is a classic spontaneous mutant exhibiting defects of the axial skeleton, hindgut, and urogenital system. We used meiotic mapping in 1,497 segregants to localize the mutation to a 42.8-kb intergenic segment on chromosome 2. Resequencing of this region identified an 8.5-kb early retrotransposon (ETn insertion within the highly conserved regulatory sequences upstream of Pancreas Specific Transcription Factor, 1a (Ptf1a. This mutation resulted in up to tenfold increased expression of Ptf1a as compared to wild-type embryos at E9.5 but no detectable changes in the expression levels of other neighboring genes. At E9.5, Sd mutants exhibit ectopic Ptf1a expression in embryonic progenitors of every organ that will manifest a developmental defect: the notochord, the hindgut, and the mesonephric ducts. Moreover, at E 8.5, Sd mutant mice exhibit ectopic Ptf1a expression in the lateral plate mesoderm, tail bud mesenchyme, and in the notochord, preceding the onset of visible defects such as notochord degeneration. The Sd heterozygote phenotype was not ameliorated by Ptf1a haploinsufficiency, further suggesting that the developmental defects result from ectopic expression of Ptf1a. These data identify disruption of the spatio-temporal pattern of Ptf1a expression as the unifying mechanism underlying the multiple congenital defects in Danforth's short tail mouse. This striking example of an enhancer mutation resulting in profound developmental defects suggests that disruption of conserved regulatory elements may also contribute to human malformation syndromes.

  3. First molecular evidence of Toxoplasma gondii in opossums (Didelphis virginiana) from Yucatan, Mexico.

    Science.gov (United States)

    Torres-Castro, M; Noh-Pech, H; Puerto-Hernández, R; Reyes-Hernández, B; Panti-May, A; Hernández-Betancourt, S; Yeh-Gorocica, A; González-Herrera, L; Zavala-Castro, J; Puerto, F I

    2016-01-01

    Toxoplasma gondii is an obligate intracellular parasite recognized as a causal agent of toxoplasmosis; zoonotic disease endemic in many countries worldwide, including Mexico. Different species of animals participate in the wild cycle infection, including opossums of the species Didelphis virginiana. Thirteen D. virginiana were captured in Yucatan, Mexico. Detection of T. gondii was achieved by Polymerase Chain Reaction, which determined an infection of 76.9% (10/13) in brains. Positive amplicons were sequenced for analysis, this produced results similar to T. gondii with identity and coverage values of 98% and 96-100%, respectively. This study presents the first molecular evidence of the circulation of T. gondii in D. virginiana from Mexico.

  4. Morphologic aspects of Tetratrichomonas didelphidis isolated from opossums Didelphis marsupialis and Lutreolina crassicaudata

    Directory of Open Access Journals (Sweden)

    Tiana Tasca

    2001-02-01

    Full Text Available Tetratrichomonas didelphidis (Hegner & Ratcliffe, 1927 Andersen & Reilly, 1965 is a flagellate protozoan found in the intestine, cecum, and colon of Didelphis marsupialis. The parasitic protozoa used in this study was found and isolated in the intestine of opossums in Pavlova starch-containing medium in Florianópolis, State of Santa Catarina, Brazil, from D. marsupialis and Lutreolina crassicaudata. The strains were cultivated in Diamond medium without maltose and with starch solution, pH 7.5 at 28°C. The specimens were stained by the Giemsa method and Heidenhain's iron hematoxylin. The light microscopy study of the trophozoites revealed the same morphologic characteristics as specimens previously described.

  5. Development of the lateral ventricular choroid plexus in a marsupial, Monodelphis domestica.

    Science.gov (United States)

    Liddelow, Shane A; Dziegielewska, Katarzyna M; Vandeberg, John L; Saunders, Norman R

    2010-10-05

    Choroid plexus epithelial cells are the site of blood/cerebrospinal fluid (CSF) barrier and regulate molecular transfer between the two compartments. Their mitotic activity in the adult is low. During development, the pattern of growth and timing of acquisition of functional properties of plexus epithelium are not known. Numbers and size of choroid plexus epithelial cells and their nuclei were counted and measured in the lateral ventricular plexus from the first day of its appearance until adulthood. Newborn Monodelphis pups were injected with 5-bromo-2-deoxyuridine (BrdU) at postnatal day 3 (P3), P4 and P5. Additional animals were injected at P63, P64 and P65. BrdU-immunopositive nuclei were counted and their position mapped in the plexus structure at different ages after injections. Double-labelling immunocytochemistry with antibodies to plasma protein identified post-mitotic cells involved in protein transfer. Numbers of choroid plexus epithelial cells increased 10-fold between the time of birth and adulthood. In newborn pups each consecutive injection of BrdU labelled 20-40 of epithelial cells counted. After 3 injections, numbers of BrdU positive cells remained constant for at least 2 months. BrdU injections at an older age (P63, P64, P65) resulted in a smaller number of labelled plexus cells. Numbers of plexus cells immunopositive for both BrdU and plasma protein increased with age indicating that protein transferring properties are acquired post mitotically. Labelled nuclei were only detected on the dorsal arm of the plexus as it grows from the neuroependyma, moving along the structure in a 'conveyor belt' like fashion. The present study established that lateral ventricular choroid plexus epithelial cells are born on the dorsal side of the structure only. Cells born in the first few days after choroid plexus differentiation from the neuroependyma remain present even two months later. Protein-transferring properties are acquired post-mitotically and relatively

  6. Development of the lateral ventricular choroid plexus in a marsupial, Monodelphis domestica

    Directory of Open Access Journals (Sweden)

    VandeBerg John L

    2010-10-01

    Full Text Available Abstract Background Choroid plexus epithelial cells are the site of blood/cerebrospinal fluid (CSF barrier and regulate molecular transfer between the two compartments. Their mitotic activity in the adult is low. During development, the pattern of growth and timing of acquisition of functional properties of plexus epithelium are not known. Methods Numbers and size of choroid plexus epithelial cells and their nuclei were counted and measured in the lateral ventricular plexus from the first day of its appearance until adulthood. Newborn Monodelphis pups were injected with 5-bromo-2-deoxyuridine (BrdU at postnatal day 3 (P3, P4 and P5. Additional animals were injected at P63, P64 and P65. BrdU-immunopositive nuclei were counted and their position mapped in the plexus structure at different ages after injections. Double-labelling immunocytochemistry with antibodies to plasma protein identified post-mitotic cells involved in protein transfer. Results Numbers of choroid plexus epithelial cells increased 10-fold between the time of birth and adulthood. In newborn pups each consecutive injection of BrdU labelled 20-40 of epithelial cells counted. After 3 injections, numbers of BrdU positive cells remained constant for at least 2 months. BrdU injections at an older age (P63, P64, P65 resulted in a smaller number of labelled plexus cells. Numbers of plexus cells immunopositive for both BrdU and plasma protein increased with age indicating that protein transferring properties are acquired post mitotically. Labelled nuclei were only detected on the dorsal arm of the plexus as it grows from the neuroependyma, moving along the structure in a 'conveyor belt' like fashion. Conclusions The present study established that lateral ventricular choroid plexus epithelial cells are born on the dorsal side of the structure only. Cells born in the first few days after choroid plexus differentiation from the neuroependyma remain present even two months later. Protein

  7. Microbial communities involved in methane production from hydrocarbons in oil sands tailings.

    Science.gov (United States)

    Siddique, Tariq; Penner, Tara; Klassen, Jonathan; Nesbø, Camilla; Foght, Julia M

    2012-09-04

    Microbial metabolism of residual hydrocarbons, primarily short-chain n-alkanes and certain monoaromatic hydrocarbons, in oil sands tailings ponds produces large volumes of CH(4) in situ. We characterized the microbial communities involved in methanogenic biodegradation of whole naphtha (a bitumen extraction solvent) and its short-chain n-alkane (C(6)-C(10)) and BTEX (benzene, toluene, ethylbenzene, and xylenes) components using primary enrichment cultures derived from oil sands tailings. Clone libraries of bacterial 16S rRNA genes amplified from these enrichments showed increased proportions of two orders of Bacteria: Clostridiales and Syntrophobacterales, with Desulfotomaculum and Syntrophus/Smithella as the closest named relatives, respectively. In parallel archaeal clone libraries, sequences affiliated with cultivated acetoclastic methanogens (Methanosaetaceae) were enriched in cultures amended with n-alkanes, whereas hydrogenotrophic methanogens (Methanomicrobiales) were enriched with BTEX. Naphtha-amended cultures harbored a blend of these two archaeal communities. The results imply syntrophic oxidation of hydrocarbons in oil sands tailings, with the activities of different carbon flow pathways to CH(4) being influenced by the primary hydrocarbon substrate. These results have implications for predicting greenhouse gas emissions from oil sands tailings repositories.

  8. Trypanosoma cruzi: vertebrate and invertebrate cycles in the same mammal host, the opossum Didelphis marsupialis

    Directory of Open Access Journals (Sweden)

    Maria P. Deane

    1984-12-01

    Full Text Available Epimastigotes multiplying extracellularly and metacyclic trypomastigotes, stages that correspond to the cycle of Trypanosoma cruzi in the intestinal lumen of its insect vector, were consistently found in the lumen of the anal glands of opossums Didelphis marsupialis inoculated subcutaneously with infective feces of triatomid bugs.No gambá (Didelphis marsupialis foi observado um ciclo extracelular do Trypanosoma cruzi: o parasita crescia abundantemente no material de secreção acumulado no lumen das glandulas anais de animais criados em cativeiro e infectados por via subcutanea com fezes de triatomineos.

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

    Science.gov (United States)

    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 lost/regenerating tails for nocturnal lizards (all 246 spp., P pressure.

  10. First molecular evidence of Toxoplasma gondii in opossums (Didelphis virginiana from Yucatan, Mexico

    Directory of Open Access Journals (Sweden)

    M. Torres-Castro

    2016-03-01

    Full Text Available Toxoplasma gondii is an obligate intracellular parasite recognized as a causal agent of toxoplasmosis; zoonotic disease endemic in many countries worldwide, including Mexico. Different species of animals participate in the wild cycle infection, including opossums of the species Didelphis virginiana. Thirteen D. virginiana were captured in Yucatan, Mexico. Detection of T. gondii was achieved by Polymerase Chain Reaction, which determined an infection of 76.9% (10/13 in brains. Positive amplicons were sequenced for analysis, this produced results similar to T. gondii with identity and coverage values of 98% and 96-100%, respectively. This study presents the first molecular evidence of the circulation of T. gondii in D. virginiana from Mexico.

  11. Streptococcus didelphis sp. nov., a streptococcus with marked catalase activity isolated from opossums (Didelphis virginiana) with suppurative dermatitis and liver fibrosis.

    Science.gov (United States)

    Rurangirwa, F R; Teitzel, C A; Cui, J; French, D M; McDonough, P L; Besser, T

    2000-03-01

    beta-Haemolytic, catalase-positive, Gram-positive cocci that formed chains in broth media but did not react with Lancefield group antisera were isolated from skin lesions, spleen, liver and lungs of nine opossums, including eight from a research colony and one from a wildlife rehabilitation organization. The isolates had vigorous catalase activity that was retained on initial passage on non-blood-containing media, but this activity was lost in subsequent passages. The use of standard phenotypic tests did not lead to satisfactory identification of these organisms beyond the genus level, even if the aberrant catalase reaction was not considered. The 16S rRNA gene sequence of the isolates was most similar (96%) to Streptococcus dysgalactiae, but distinct from that species as 16S rRNA gene similarity of different strains of S. dysgalactiae was > 99%. Characterization of biochemical reactions and cell-wall fatty acid profiles also revealed significant differences between the opossum isolates and all other known Streptococcus spp., thus it is proposed as a new species with the name Streptococcus didelphis, sp. nov. The type strain is ATCC 700828T.

  12. Karyotype characterization and nucleolar organizer regions of marsupial species (Didelphidae from areas of Cerrado and Atlantic Forest in Brazil

    Directory of Open Access Journals (Sweden)

    Núbia P. Pereira

    2008-01-01

    Full Text Available The karyotypes of 23 specimens belonging to 16 species from nine genera of Brazilian marsupials (family Didelphidae were studied. The animals were collected in eight localities of Cerrado or Atlantic Forest biomes in the states of Goiás, Tocantins and São Paulo. The karyotypes were analyzed after conventional Giemsa staining and silver staining of the nucleolus organizer regions (Ag-NORs. New karyotypic data were obtained for Gracilinanus microtarsus (2n = 14, FN = 24, Marmosops paulensis (2n = 14, FN = 24 , Micoreus paraguayanus (2n = 14, FN = 20 and Monodelphis rubida (2n = 18, FN = 32 and are discussed in detail. The karyotypes of G. microtarsus , M. paulensis and M. paraguayanus include three large pairs of submetacentrics (pairs 1, 2 and 3 and a medium-sized metacentric or submetacentric pair 4. Pairs 5 and 6 are small submetacentrics in G. microtarsus and M. paulensis and acrocentrics in M. paraguayanus . M. paulensis presented a single Ag-NOR in pair 6 (6p6p, while M. paraguayanus exhibited multiple Ag-NORs in pairs 5 and 6 (5pq5pq6p6p. There was variation in size and morphology of the sex chromosomes among these species. Monodelphis rubida presented a karyotype with 2n = 18 and FN = 32 composed of a large submetacentric pair 1, a medium-sized metacentric pair 2 and six pairs of submetacentrics (pairs 3 through 8. The X was a small acrocentric and the Y was dot-like. A single Ag-NOR bearing pair (5p5p characterized M. rubida. Relevant karyotypic information was obtained for 19 specimens belonging to 12 species collected in areas sampled for the first time [ Caluromys lanatus and C. philander (2n = 14, FN = 20, Gracilinanus emiliae (2n = 14, FN = 24, Marmosa murina , Metachirus nudicaudatus and Micoureus demerarae (2n = 14, FN = 20, Monodelphis americana (2n = 18, FN = 32 and M. domestica (2n = 18, FN = 20, and Didelphis marsupialis, Philander frenata, P. opossum and P. sp (2n = 22, FN = 20]. Although the karyotypes were relatively

  13. Consolidation of tailings

    International Nuclear Information System (INIS)

    Nelson, J.D.; Wardwell, R.E.; Abt, S.R.; Staub, W.P.

    1983-09-01

    The integrity of cover systems placed on tailings impoundments will be affected by the potential for differential settlement of the tailings surface. Settlement of the sand fraction will occur relatively rapidly. The slimes will take longer time for consolidation and will produce greater settlement. This report reviews the phenomenon of consolidation for saturated and unsaturated tailings. The effect of load application by cover placement and the extent to which dewatering of tailings will cause consolidation are considered. In addition, the feasibility of inducing consolidation by alternative means and the potential applicability of these methods to tailings impoundments reclamation are discussed. Differential settlement of the tailings will cause tensile strain to be developed in covers. This strain could be large enough to cause cracking within a relatively brittle compacted clay. Dewatering of tailings by drainage can cause settlement even greater than that by placement of a cover material. Dewatering of the tailings would also increase the stability of the tailings surface, thereby enhancing reclamation operations. Consequently, in view of the enhanced surface stability and the fact that a portion of the differential settlement can be accomplished prior to cover placement, dewatering of tailings impoundments during operations may have benefical effects

  14. Tail posture predicts tail biting outbreaks at pen level in weaner pigs

    DEFF Research Database (Denmark)

    Lahrmann, Helle Pelant; Hansen, Christian Fink; D'Eath, Rick

    2018-01-01

    posture and behaviour could be detected at pen level between upcoming tail biting pens (T-pens) and control pens (C-pens). The study included 2301 undocked weaner pigs in 74 pens (mean 31.1 pigs/pen; SD 1.5). Tails were scored three times weekly (wound freshness, wound severity and tail length) between 07......Detecting a tail biting outbreak early is essential to reduce the risk of pigs getting severe tail damage. A few previous studies suggest that tail posture and behavioural differences can predict an upcoming outbreak. The aim of the present study was therefore to investigate if differences in tail......:00 h-14:00 h from weaning until a tail biting outbreak. An outbreak (day 0) occurred when at least four pigs had a tail damage, regardless of wound freshness. On average 7.6 (SD 4.3) pigs had a damaged tail (scratches + wound) in T-pens on day 0. Tail posture and behaviour (activity, eating...

  15. Concurrent presence of Sarcocystis neurona sporocysts, Besnoitia darlingi tissue cysts, and Sarcocystis inghami sarcocysts in naturally infected opossums (Didelphis virginiana).

    Science.gov (United States)

    Elsheikha, H M; Fitzgerald, S D; Rosenthal, B M; Mansfield, L S

    2004-07-01

    Opossums (Didelphis virginiana) are exposed to a wide range of coccidia through feeding on a variety of foods, including, but not limited to, carrion, insects, and nestling birds. Abundant D. virginiana populations in urban and suburban areas can be important reservoirs of parasitic infection because of their profuse and prolonged excretion of the sporocysts of several species of Sarcocystis, their omnivorous diet, and their relatively long life span. This report describes 2 adult female opossums found to be simultaneously infected with the tissue cysts of Besnoitia darlingi, sarcocysts of Sarcocystis inghami, as well as with the intestinal sporocysts of S. neurona. Cysts typical of B. darlingi based on gross, histological, and ultrastructural characteristics were disseminated throughout the visceral organs, musculature, ears, and skin. The S. neurona and B. darlingi infections were confirmed by comparative sequence analysis of polymerase chain reaction-amplified diagnostic genetic loci. Sarcocysts of S. inghami are also described. Such examples of multiple parasitic infections show that concurrent infections occur naturally. The propensity for species to coexist should be considered in the differential diagnosis of tissue cyst-forming coccidian protozoa and may have important epidemiological and evolutionary implications.

  16. Fractal characters and hurst exponent of radon exhalation rate from uranium Tailings

    International Nuclear Information System (INIS)

    Hu Hanqiao; Tan Kaixuan; Li Chunguang; Lv Junwen; Liu Dong

    2010-01-01

    The uranium tailings radon exhalation is an important environmental problem. The change of the radon exhalation rate of uranium tailings with the time through laboratory experiments is measured, and the results show that the radon exhalation rate of the tailings change obviously with time in non-periodic oscillations. Applying fractal analysis to the radon exhalation rate time-series data by R/S method, the Hurst exponent of the entire time series data is 0.83, the fractal dimension is 1.17. Mobile Hurst exponent is between 0.5 and 0.8 in most cases. The Hurst exponent of the experiments in the later part are below 0.5. The exhalation rate of uranium tailings radon does not meet the long-term trend of random walk theory, the radon exhalation rate has long-term memory, but the short-term memory is not distinct. The radon exhalation from uranium tailings is a deterministic chaotic dynamics. (authors)

  17. BURST TAILS FROM SGR J1550–5418 OBSERVED WITH THE ROSSI X-RAY TIMING EXPLORER

    Energy Technology Data Exchange (ETDEWEB)

    Muş, Sinem Şaşmaz; Gögüş, Ersin; Kaneko, Yuki; Chakraborty, Manoneeta; Aydın, Berk, E-mail: sinemsmus@sabanciuniv.edu [Sabancı University, Faculty of Engineering and Natural Sciences, Orhanlı Tuzla 34956 Istanbul (Turkey)

    2015-07-01

    We present the results of our extensive search using the Bayesian block method for long tails following short bursts from a magnetar, SGR J1550–5418, over all RXTE observations of the source. We identified four bursts with extended tails, most of which occurred during its 2009 burst active episode. The durations of tails range between ∼13 s and over 3 ks, which are much longer than the typical duration of bursts. We performed detailed spectral and temporal analyses of the burst tails. We find that the spectra of three tails show a thermal nature with a trend of cooling throughout the tail. We compare the results of our investigations with the properties of four other extended tails detected from SGR 1900+14 and SGR 1806–20 and suggest a scenario for the origin of the tail in the framework of the magnetar model.

  18. Sarcocystis speeri N. sp. (Protozoa: Sarcocystidae) from the opossum (Didelphis virginiana).

    Science.gov (United States)

    Dubey, J P; Lindsay, D S

    1999-10-01

    The North American opossum (Didelphis virginiana) is host to at least 3 species of Sarcocystis: Sarcocystisfalcatula, Sarcocystis neurona, and a recently recognized Sarcocystis sp. A new name, Sarcocystis speeri, is proposed for the third unnamed Sarcocystis. Immunodeficient mice are an experimental intermediate host for S. speeri. Sarcocystis speeri sporocysts are 12-15 x 8-10 microm in size, and its schizonts are found in many organs of mice. Sarcocysts of S. speeri are found in skeletal muscles and they are up to 5 mm long and filiform. By light microscopy, the sarcocyst wall is thin (<1 microm thick); ultrastructurally, the cyst wall is up to 1.8 microm thick and has characteristic steeple-shaped villar protrusions surmounted by a spire. Sarcocystis speeri schizonts are morphologically and antigenically distinct from schizonts of S. neurona, and S. speeri sporocysts were not infective to budgerigars (Melopsittacus undulatus).

  19. Extracellular Trap Formation in Response to Trypanosoma cruzi Infection in Granulocytes Isolated From Dogs and Common Opossums, Natural Reservoir Hosts

    Directory of Open Access Journals (Sweden)

    Nicole de Buhr

    2018-05-01

    Full Text Available Granulocytes mediate the first line of defense against infectious diseases in humans as well as animals and they are well known as multitasking cells. They can mediate antimicrobial activity by different strategies depending on the pathogen they encounter. Besides phagocytosis, a key strategy against extracellular pathogens is the formation of extracellular traps (ETs. Those ETs mainly consist of DNA decorated with antimicrobial components and mediate entrapment of various pathogens. In the last years, various studies described ET formation as response to bacteria, viruses and parasites e.g., Trypanosma (T. cruzi. Nevertheless, it is not fully understood, if ET formation helps the immune system to eliminate intracellular parasites. The goal of this study was to analyze ET formation in response to the intracellular parasite Trypanosma (T. cruzi by granulocytes derived from animals that serve as natural reservoir. Thus, we investigated the ET formation in two T. cruzi reservoirs, namely dogs as domestic animal and common opossums (Didelphis marsupialis as wild animal. Granulocytes were harvested from fresh blood by density gradient centrifugation and afterwards incubated with T. cruzi. We conducted the analysis by determination of free DNA and immunofluorescence microscopy. Using both methods, we show that T. cruzi efficiently induces ET formation in granulocytes derived from common opossum as well as dog blood. Most ETs from both animal species as response to T. cruzi are decorated with the protease neutrophil elastase. Since T. cruzi is well known to circulate over years in both analyzed animals as reservoirs, it may be assumed that T. cruzi efficiently evades ET-mediated killing in those animals. Therefore, ETs may not play a major role in efficient elimination of the pathogen from the blood of dogs or common opossums as T. cruzi survives in niches of their body. The characterization of granulocytes in various animals and humans may be helpful

  20. Prevalence of antibodies to Trypanosoma cruzi, Toxoplasma gondii, Encephalitozonn cuniculi, Sarcocystis neurona, Besnoitia darlingi, and Neospora caninum in North American opossum, Didelphis virginiana, from Southern Louisian

    Science.gov (United States)

    We examined the prevalence of antibodies to zoonotic protozoan parasites (Trypanosoma cruzi, Toxoplasma gondii, and Encephalitozoon cuniculi) and protozoan’s of veterinary importance (Neospora caninum, Sarcocystis neurona and Besnoitia darlingi) in a population of North American opossums (Didelphis...

  1. Tail gut cyst.

    Science.gov (United States)

    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.

  2. Regeneration of supraspinal axons after transection of the thoracic spinal cord in the developing opossum, Didelphis virginiana.

    Science.gov (United States)

    Wang, X M; Terman, J R; Martin, G F

    1998-08-17

    When the thoracic spinal cord of the North American opossum is transected early in development, supraspinal axons grow through the lesion. In the experiments reported here, we asked whether regeneration of cut axons contributes to such growth. Fast Blue (FB) was injected into the lumbar cord on postnatal day (PD)5, 8, 15, or 20. Five days later, FB was removed by gentle suction, and the spinal cord was transected at thoracic levels. Fourteen days later, rhodamine B dextran was injected between the site of the FB injection and the lesion. The pups were maintained for an additional 7-10 days before killing and perfusion. We assumed that supraspinal neurons that contained FB survived axotomy and those that contained both FB and rhodamine B dextran supported regenerating axons. In the PD5 group (lesioned at PD10), regenerative growth was documented for axons originating in all of the supraspinal nuclei that innervate the lumbar cord by PD10. When the injections were made at the later ages, however, neurons that supported regenerative growth were fewer in number and regionally restricted. In some cases, they were limited primarily to the red nucleus, the medullary raphe, and the adjacent reticular formation. Our results show that regeneration of cut axons contributes to growth of supraspinal axons through the lesion after transection of the thoracic cord in developing opossums and that the critical period for regenerative growth is not the same for all axons.

  3. Diversity of Sarcocystis spp shed by opossums in Brazil inferred with phylogenetic analysis of DNA coding ITS1, cytochrome B, and surface antigens.

    Science.gov (United States)

    Valadas, Samantha Y O B; da Silva, Juliana I G; Lopes, Estela Gallucci; Keid, Lara B; Zwarg, Ticiana; de Oliveira, Alice S; Sanches, Thaís C; Joppert, Adriana M; Pena, Hilda F J; Oliveira, Tricia M F S; Ferreira, Helena L; Soares, Rodrigo M

    2016-05-01

    Although few species of Sarcocystis are known to use marsupials of the genus Didelphis as definitive host, an extensive diversity of alleles of surface antigen genes (sag2, sag3, and sag4) has been described in samples of didelphid opossums in Brazil. In this work, we studied 25 samples of Sarcocystis derived from gastrointestinal tract of opossums of the genus Didelphis by accessing the variability of sag2, sag3, sag4, gene encoding cytochrome b (cytB) and first internal transcribed spacer (ITS1). Reference samples of Sarcocystis neurona (SN138) and Sarcocystis falcatula (SF1) maintained in cell culture were also analyzed. We found four allele variants of cytB, seven allele variants of ITS1, 10 allele variants of sag2, 13 allele variants of sag3, and 6 allele variants of sag4. None of the sporocyst-derived sequences obtained from Brazilian opossums revealed 100% identity to SN138 at cytB gene, nor to SN138 or SF1 at ITS1 locus. In addition, none of the sag alleles were found identical to either SF1 or SN138 homologous sequences, and a high number of new sag allele types were found other than those previously described in Brazil. Out of ten sag2 alleles, four are novel, while eight out of 13 sag3 alleles are novel and one out of six sag4 alleles is novel. Further studies are needed to clarify if such a vast repertoire of allele variants of Sarcocystis is the consequence of re-assortments driven by sexual exchange, in order to form individuals with highly diverse characteristics, such as pathogenicity, host spectrum, among others or if it only represents allele variants of different species with different biological traits. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Effect of desliming of sulphide-rich mill tailings on the long-term strength of cemented paste backfill.

    Science.gov (United States)

    Ercikdi, Bayram; Baki, Hakan; İzki, Muhammet

    2013-01-30

    This paper presents the effect of desliming on the short- and long-term strength, stability and rheological properties of cemented paste backfill (CPB) produced from two different mill tailings. A 28-day unconfined compressive strength (UCS) of ≥1.0 MPa and the maintenance of stability over 224 days of curing were selected as the design criteria for the evaluation of paste backfill performance. Desliming induced some changes in the physical, chemical, mineralogical and rheological properties of the tailings. CPB mixture of the deslimed tailings achieved the required consistency at a lower water to cement ratio. The short-term UCSs of CPB samples of the deslimed tailings were found to be 30-100% higher than those samples of the reference tailings at all the binder dosages and curing times. CPB samples of the deslimed tailings achieved the long-term stability at relatively low binder dosages (e.g. 5 wt% c.f. ≥6.1% for the reference tailings). It was also estimated that desliming could allow a 13.4-23.1% reduction in the binder consumption depending apparently on the inherent characteristics of the tailings. Over the curing period, generation of sulphate and acid by the oxidation of pyrite present in the tailings was also monitored to correlate with the strength losses observed in the long term. Scanning electron microscope (SEM) and Mercury Intrusion Porosimetry (MIP) analyses provided an insight into the microstructure of CPB and the formation of secondary mineral phases (i.e. gypsum) confirming the beneficial effect of desliming. These findings suggest that desliming can be suitably exploited for CPB of sulphide-rich mill tailings to improve the strength and stability particularly in the long term and to reduce binder consumption. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Neutralization of lethality and proteolytic activities of Malayan pit viper (Calloselasma rhodostoma) venom with North American Virginia opossum (Didelphis virginiana) serum.

    Science.gov (United States)

    Pornmanee, Piboon; Sánchez, Elda E; López, Gonzalo; Petsom, Amorn; Khow, Orawan; Pakmanee, Narumol; Chanhome, Lawan; Sangvanich, Polkit; Pérez, John C

    2008-07-01

    Malayan pit viper (Calloselasma rhodostoma) envenomation is a major health problem in South East Asia. During envenomation, venom components mainly affect the hemostatic system. The sera from the North American Virginia opossums (Didelphis virginiana) were able to neutralize the venom of the Malayan pit viper. These natural inhibitors could be explored as potential therapeutics against envenomations of a variety of venomous snake species in different geographical habitats.

  6. Structural implications of the C-terminal tail in the catalytic and stability properties of manganese peroxidases from ligninolytic fungi

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Fueyo, Elena [CSIC, Ramiro de Maeztu 9, 28040 Madrid (Spain); Acebes, Sandra [Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona (Spain); Ruiz-Dueñas, Francisco J.; Martínez, María Jesús; Romero, Antonio; Medrano, Francisco Javier, E-mail: fjmedrano@cib.csic.es [CSIC, Ramiro de Maeztu 9, 28040 Madrid (Spain); Guallar, Victor, E-mail: fjmedrano@cib.csic.es [Barcelona Supercomputing Center, Jordi Girona 29, 08034 Barcelona (Spain); ICREA, Passeig Lluís Companys 23, 08010 Barcelona (Spain); Martínez, Angel T., E-mail: fjmedrano@cib.csic.es [CSIC, Ramiro de Maeztu 9, 28040 Madrid (Spain)

    2014-12-01

    The variable C-terminal tail of manganese peroxidases, a group of enzymes involved in lignin degradation, is implicated in their catalytic and stability properties, as shown by new crystal structures, molecular-simulation and directed-mutagenesis data. Based on this structural–functional evaluation, short and long/extralong manganese peroxidase subfamilies have been accepted; the latter are characterized by exceptional stability, while it is shown for the first time that the former are able to oxidize other substrates at the same site where manganese(II) is oxidized. The genome of Ceriporiopsis subvermispora includes 13 manganese peroxidase (MnP) genes representative of the three subfamilies described in ligninolytic fungi, which share an Mn{sup 2+}-oxidation site and have varying lengths of the C-terminal tail. Short, long and extralong MnPs were heterologously expressed and biochemically characterized, and the first structure of an extralong MnP was solved. Its C-terminal tail surrounds the haem-propionate access channel, contributing to Mn{sup 2+} oxidation by the internal propionate, but prevents the oxidation of 2, 2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), which is only oxidized by short MnPs and by shortened-tail variants from site-directed mutagenesis. The tail, which is anchored by numerous contacts, not only affects the catalytic properties of long/extralong MnPs but is also associated with their high acidic stability. Cd{sup 2+} binds at the Mn{sup 2+}-oxidation site and competitively inhibits oxidation of both Mn{sup 2+} and ABTS. Moreover, mutations blocking the haem-propionate channel prevent substrate oxidation. This agrees with molecular simulations that position ABTS at an electron-transfer distance from the haem propionates of an in silico shortened-tail form, while it cannot reach this position in the extralong MnP crystal structure. Only small differences exist between the long and the extralong MnPs, which do not justify their

  7. Uranium Mill Tailings Management

    International Nuclear Information System (INIS)

    Nelson, J.D.

    1982-01-01

    This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements)

  8. More tail lesions among undocked than tail docked pigs in a conventional herd

    DEFF Research Database (Denmark)

    Lahrmann, H. P.; Busch, M. E.; D'Eath, R. B.

    2017-01-01

    The vast majority of piglets reared in the European Union (EU) and worldwide is tail docked to reduce the risk of being tail bitten, even though EU animal welfare legislation bans routine tail docking. Many conventional herds experience low levels of tail biting among tail docked pigs, however...

  9. Uranium mill tailings backfill management. Final report

    International Nuclear Information System (INIS)

    Thomson, B.M.; Heggen, R.J.

    1984-01-01

    Backfilling, the disposal of spent uranium mill tailings in empty mine stopes, has been practiced in the Grants Mineral Belt of New Mexico for nearly 20 years. The principal objective of backfilling is the prevention of roof collapse and hydraulic connection with overlying aquifers, increasing mine dewatering requirements. Backfilling is accomplished by gravity feed of a slurry of sand-fraction tailings and treated mine water into the slope. The effects of backfilling on surface discharge of mine wastewater are negligible due to the small fraction of the total flow represented by slurry decant. Furthermore, quality of the decant is not significantly below that of other mine waters. Groundwater effects of backfilling may be classified as short-term (while the mine is operational) and long-term (after dewatering operations have been terminated). Short-term effects are insignificant because of rapid and continuous flow to the mine sump. Long-term effects on aquifer water quality are predicted to be minimal due to (1) the small amount of slurry liquor present after drainage, (2) the precipitation of SO 4 and CO 3 phases, and (3) the reestablishment of reducing conditions and subsequent precipitation of major contaminants including U, As, Mo, Se, and V. 28 references, 19 figures, 9 tables

  10. Scanning electron microscopy of Turgida turgida (Nematoda: Spiruroidea), parasite of the Virginia opossum, Didelphis virginiana, from southern California.

    Science.gov (United States)

    Matey, V E; Kuperman, B I; Kinsella, J M

    2001-10-01

    Taxonomic characters for identification of Turgida turgida Rudolphi, 1819, a parasitic nematode of the Virginia opossum Didelphis virginiana, were studied by scanning electron microscopy. The distinguishing feature of the cephalic end is the presence of numerous denticles, structures associated with the internal tooth, and 2 spongelike areas on the inner side of each pseudolabia. The posterior end of male T. turgida differs from that in other species of Physalopteridae by the number of caudal papillae (22), truncated postcloacal papilla, and patterns of ventrocaudal ornamentation.

  11. A dataset on tail risk of commodities markets.

    Science.gov (United States)

    Powell, Robert J; Vo, Duc H; Pham, Thach N; Singh, Abhay K

    2017-12-01

    This article contains the datasets related to the research article "The long and short of commodity tails and their relationship to Asian equity markets"(Powell et al., 2017) [1]. The datasets contain the daily prices (and price movements) of 24 different commodities decomposed from the S&P GSCI index and the daily prices (and price movements) of three share market indices including World, Asia, and South East Asia for the period 2004-2015. Then, the dataset is divided into annual periods, showing the worst 5% of price movements for each year. The datasets are convenient to examine the tail risk of different commodities as measured by Conditional Value at Risk (CVaR) as well as their changes over periods. The datasets can also be used to investigate the association between commodity markets and share markets.

  12. Preferential methanogenic biodegradation of short-chain n-alkanes by microbial communities from two different oil sands tailings ponds.

    Science.gov (United States)

    Mohamad Shahimin, Mohd Faidz; Foght, Julia M; Siddique, Tariq

    2016-05-15

    Oil sands tailings ponds harbor diverse anaerobic microbial communities capable of methanogenic biodegradation of solvent hydrocarbons entrained in the tailings. Mature fine tailings (MFT) from two operators (Albian and CNRL) that use different extraction solvents were incubated with mixtures of either two (n-pentane and n-hexane) or four (n-pentane, n-hexane, n-octane and n-decane) n-alkanes under methanogenic conditions for ~600 d. Microbes in Albian MFT began methane production by ~80 d, achieving complete depletion of n-pentane and n-hexane in the two-alkane mixture and their preferential biodegradation in the four-alkane mixture. Microbes in CNRL MFT preferentially metabolized n-octane and n-decane in the four-alkane mixture after a ~80 d lag but exhibited a lag of ~360 d before commencing biodegradation of n-pentane and n-hexane in the two-alkane mixture. 16S rRNA gene pyrosequencing revealed Peptococcaceae members as key bacterial n-alkane degraders in all treatments except CNRL MFT amended with the four-alkane mixture, in which Anaerolineaceae, Desulfobacteraceae (Desulfobacterium) and Syntrophaceae (Smithella) dominated during n-octane and n-decane biodegradation. Anaerolineaceae sequences increased only in cultures amended with the four-alkane mixture and only during n-octane and n-decane biodegradation. The dominant methanogens were acetoclastic Methanosaetaceae. These results highlight preferential n-alkane biodegradation by microbes in oil sands tailings from different producers, with implications for tailings management and reclamation. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Presentations of the CONRAD tailings seminar : exploring the past, present and future of tailings technologies

    International Nuclear Information System (INIS)

    2004-01-01

    This symposium explored oil sand tailings activities in Canada and their associated technologies. It was attended by active and prospective tailings researchers and developers of tailings technology who addressed timely issues regarding mature fine tailings, consolidated tailings, thickened tailings, and emerging tailings technologies. The collaborative research projects that are underway at the Oil Sands Tailings Research Facility were also discussed along with other topics such as tailings ponds management, water treatment, water quality and water supply security. All 16 presentations featured at this conference were indexed separately for inclusion in this database

  14. Galaxies with long tails

    International Nuclear Information System (INIS)

    Schweizer, F.

    1978-01-01

    Two types of galaxies with long tails are described. The first occurs in pairs, each individual one having a long tail and the second occurs on its own with two tails. NGC 7252 shows several characteristics which one would expect of a merger: a pair of tidal tails despite the splendid isolation, a single nucleus, tail motions in opposite directions relative to the nucleus, and chaotic motions of a strangely looped main body. (C.F.)

  15. Attitudes of Dutch Pig Farmers Towards Tail Biting and Tail Docking

    OpenAIRE

    Bracke, M.B.M.; Lauwere, de, C.C.; Wind, S.M.M.; Zonderland, J.J.

    2013-01-01

    The Dutch policy objective of a fully sustainable livestock sector without mutilations by 2023 is not compatible with the routine practice of tail docking to minimize the risk of tail biting. To examine farmer attitudes towards docking, a telephone survey was conducted among 487 conventional and 33 organic Dutch pig farmers. “Biting” (of tails, ears, or limbs) was identified by the farmers as a main welfare problem in pig farming. About half of the farmers reported to have no tail biting prob...

  16. Tail function during arboreal quadrupedalism in squirrel monkeys (Saimiri boliviensis) and tamarins (Saguinus oedipus).

    Science.gov (United States)

    Young, Jesse W; Russo, Gabrielle A; Fellmann, Connie D; Thatikunta, Meena A; Chadwell, Brad A

    2015-10-01

    The need to maintain stability on narrow branches is often presented as a major selective force shaping primate morphology, with adaptations to facilitate grasping receiving particular attention. The functional importance of a long and mobile tail for maintaining arboreal stability has been comparatively understudied. Tails can facilitate arboreal balance by acting as either static counterbalances or dynamic inertial appendages able to modulate whole-body angular momentum. We investigate associations between tail use and inferred grasping ability in two closely related cebid platyrrhines-cotton-top tamarins (Saguinus oedipus) and black-capped squirrel monkeys (Saimiri boliviensis). Using high-speed videography of captive monkeys moving on 3.2 cm diameter poles, we specifically test the hypothesis that squirrel monkeys (characterized by grasping extremities with long digits) will be less dependent on the tail for balance than tamarins (characterized by claw-like nails, short digits, and a reduced hallux). Tamarins have relatively longer tails than squirrel monkeys, move their tails through greater angular amplitudes, at higher angular velocities, and with greater angular accelerations, suggesting dynamic use of tail to regulate whole-body angular momentum. By contrast, squirrel monkeys generally hold their tails in a comparatively stationary posture and at more depressed angles, suggesting a static counterbalancing mechanism. This study, the first empirical test of functional tradeoffs between grasping ability and tail use in arboreal primates, suggests a critical role for the tail in maintaining stability during arboreal quadrupedalism. Our findings have the potential to inform our functional understanding of tail loss during primate evolution. © 2015 Wiley Periodicals, Inc.

  17. The Risk of Individual Stocks’ Tail Dependence with the Market and Its Effect on Stock Returns

    Directory of Open Access Journals (Sweden)

    Guobin Fan

    2015-01-01

    Full Text Available Traditional beta is only a linear measure of overall market risk and places equal emphasis on upside and downside risks, but actually the latter is always much stronger probably due to the trading mechanism like short-sale constraints. Therefore, this paper employs the nonlinear measure, tail dependence, to measure the extreme downside risks that individual stocks crash together with the whole market and investigates whether such tail dependence risks will affect stock returns. Our empirical evidence based on Shanghai A shares confirms that most stocks display nonnegligible tail dependence with the whole market, and, more importantly, such tail dependence risks can indeed provide additional information beyond beta and other factors for asset pricing. In cross-sectional regression, it is proved that this tail dependence does help to explain monthly returns on Shanghai A shares, whereas the time-series regression further indicates that mimicking portfolio returns for tail dependence can capture strong common variation of Shanghai A stock returns.

  18. Heavy metal leaching from mine tailings as affected by plants

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-01

    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 M 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.

  19. Bar-tailed

    NARCIS (Netherlands)

    Duijns, S.; Hidayati, N.A.; Piersma, T.

    2013-01-01

    Capsule Across the European wintering range Bar-tailed Godwits Limosa lapponica lapponica selected polychaete worms and especially Ragworms Hediste diversicolor, with differences between areas due to variations in prey availability.Aims To determine the diet of Bar-tailed Godwits across their

  20. TAIL ASYMPTOTICS OF LIGHT-TAILED WEIBULL-LIKE SUMS

    DEFF Research Database (Denmark)

    Asmussen, Soren; Hashorva, Enkelejd; Laub, Patrick J.

    2017-01-01

    We consider sums of n i.i.d. random variables with tails close to exp{-x(beta)} for some beta > 1. Asymptotics developed by Rootzen (1987) and Balkema, Kluppelberg, and Resnick (1993) are discussed from the point of view of tails rather than of densities, using a somewhat different angle...

  1. Effects of weather and tailings properties on tailings drying times

    Energy Technology Data Exchange (ETDEWEB)

    Gantzer, C.; Fasking, T.; Costello, M.; Greenwood, J. [Barr Engineering, Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation presented the results of a study conducted to determine the effects of weather and tailings properties on tailings drying times. Weather conditions have a significant impact the potential evaporation (PE) and actual evaporation (AE) of oil sands tailings. A 2-stage drying of slurry at a constant PE was conducted to determine the shrinkage limit of untreated mature fine tailings (MFT). An evaporation and seepage model was used to determine maximum first-stage drying rates. Measurements were also taken in a wind tunnel. Potential evaporation rates were calculated and evaporative water losses from the MFT were determined. Estimated drying times were presented. Results of the approach were compared with field measurements conducted in a previous study. Results of the study showed that evaporative water loss rates for May through August were limited by the properties of the tailings. Water loss rates were limited by weather for other months in the year-long study. tabs., figs.

  2. Cameco engineered tailings program: linking research with industrial processes for improved tailings performance

    International Nuclear Information System (INIS)

    Kotzer, T.; Hendry, M.J.

    2011-01-01

    The waste product from uranium mining and milling that generates the greatest public and regulatory concern is tailings. The tailings contain all of the mined material except uranium plus a host of processing reagents. These minerals and compounds have the potential to harm the local environment if not deposited in a fashion that is both geochemically and geotechnically stable. Environmental leadership impels Cameco Corporation to ensure that the methods used to dispose of tailings are at the forefront of best available technologies whereby tailings production results in a product with geotechnical and geochemical characteristics that minimize the environmental impact associated with long-term storage of this product. Cameco has developed an Engineered Tailings (ET) program to ensure optimization of long-term tailings performance and minimal impacts of elements of concern (EOCs) to the receiving environment, regardless of the ore being milled. Within this program chemical and physical performance of tailings from geochemical and geotechnical investigations and baseline environmental data, integrated with regulatory requirements and corporate commitments, will be used to evaluate and set criteria for mill- and tailings management facilities-based chemical and physical tailings characteristics, identify key knowledge gaps, prioritize areas of concern and implement appropriate responses. This paper provides an overview of the Engineered Tailings program, the research being conducted as part of the ET program, and how it links with present and future Cameco operations. (author)

  3. Uranium tailings sampling manual

    International Nuclear Information System (INIS)

    Feenstra, S.; Reades, D.W.; Cherry, J.A.; Chambers, D.B.; Case, G.G.; Ibbotson, B.G.

    1985-01-01

    The purpose of this manual is to describe the requisite sampling procedures for the application of uniform high-quality standards to detailed geotechnical, hydrogeological, geochemical and air quality measurements at Canadian uranium tailings disposal sites. The selection and implementation of applicable sampling procedures for such measurements at uranium tailings disposal sites are complicated by two primary factors. Firstly, the physical and chemical nature of uranium mine tailings and effluent is considerably different from natural soil materials and natural waters. Consequently, many conventional methods for the collection and analysis of natural soils and waters are not directly applicable to tailings. Secondly, there is a wide range in the physical and chemical nature of uranium tailings. The composition of the ore, the milling process, the nature of tailings depositon, and effluent treatment vary considerably and are highly site-specific. Therefore, the definition and implementation of sampling programs for uranium tailings disposal sites require considerable evaluation, and often innovation, to ensure that appropriate sampling and analysis methods are used which provide the flexibility to take into account site-specific considerations. The following chapters describe the objective and scope of a sampling program, preliminary data collection, and the procedures for sampling of tailings solids, surface water and seepage, tailings pore-water, and wind-blown dust and radon

  4. Establishment of Besnoitia darlingi from opossums (Didelphis virginiana) in experimental intermediate and definitive hosts, propagation in cell culture, and description of ultrastructural and genetic characteristics.

    Science.gov (United States)

    Dubey, J P; Lindsay, D S; Rosenthal, B M; Sreekumar, C; Hill, D E; Shen, S K; Kwok, O C H; Rickard, L G; Black, S S; Rashmir-Raven, A

    2002-07-01

    Besnoitia darlingi from naturally infected opossums (Didelphis virginiana) from Mississippi, USA, was propagated experimentally in mice, cats, and cell culture and was characterised according to ultrastructural, genetic, and life-history characteristics. Cats fed tissue cysts from opossums shed oocysts with a prepatent period of nine or 11 days. Oocysts, bradyzoites, or tachyzoites were infective to outbred and interferon-gamma gene knockout mice. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey cells and revived after an 18-month storage in liquid nitrogen. Schizonts were seen in the small intestinal lamina propria of cats fed experimentally-infected mouse tissues. These schizonts measured up to 45 x 25 microm and contained many merozoites. A few schizonts were present in mesenteric lymph nodes and livers of cats fed tissue cysts. Ultrastructurally, tachyzoites and bradyzoites of B. darlingi were similar to other species of Besnoitia. A close relationship to B. besnoiti and an even closer relationship to B. jellisoni was indicated for B. darlingi on the basis of the small subunit and ITS-1 portions of nuclear ribosomal DNA.

  5. Plants from the abandoned Nacozari mine tailings: evaluation of their phytostabilization potential

    Directory of Open Access Journals (Sweden)

    Alina E. Santos

    2017-05-01

    Full Text Available Phytostabilization is a remediation technology that uses plants for in-situ stabilization of contamination in soils and mine tailings. The objective of this study was to identify native plant species with potential for phytostabilization of the abandoned mine tailings in Nacozari, Sonora in northern Mexico. A flora of 42 species in 16 families of angiosperms was recorded on the tailings site and the abundance of the most common perennial species was estimated. Four of the five abundant perennial species showed evidence of regeneration: the ability to reproduce and establish new seedlings. A comparison of selected physicochemical properties of the tailings in vegetated patches with adjacent barren areas suggests that pH, electrical conductivity, texture, and concentration of potentially toxic elements do not limit plant distribution. For the most abundant species, the accumulation factor for most metals was <1, with the exception of Zn in two species. A short-term experiment on adaptation revealed limited evidence for the formation of local ecotypes in Prosopis velutina and Amaranthus watsonii. Overall, the results of this study indicate that five native plant species might have potential for phytostabilization of the Nacozari tailings and that seed could be collected locally to revegetate the site. More broadly, this study provides a methodology that can be used to identify native plants and evaluate their phytostabilization potential for similar mine tailings.

  6. Effects of various tailings covers on radon gas emanation from pyritic uranium tailings

    International Nuclear Information System (INIS)

    Dave, N.K.; Lim, T.P.

    1987-01-01

    Radon emanation studies were carried out at an inactive pyritic uranium tailings site in Elliot Lake, Ontario, Canada, to evaluate the effects of various existing dry and wet covers on radon flux rates. Measurements were taken using activated charcoal cartridges for various surface covers consisting of bare, vegetated, acidophilic moss with high degree of water saturation, compacted crushed rock and gravel, and winter snow. The results showed that at a given site, there was no significant difference in radon emanation rates between various tailings covers and bare tailings. In particular, no increase In radon emanation rates from vegetated areas compared to bare tailings was observed. Radon emanation rates varied spatially depending on tailings grain size, porosity, moisture content and on pressure and water table variations. The emanation rates were higher for tailings with low water contents compared to those for wet and moss covered tailings

  7. Comparative sacral morphology and the reconstructed tail lengths of five extinct primates: Proconsul heseloni, Epipliopithecus vindobonensis, Archaeolemur edwardsi, Megaladapis grandidieri, and Palaeopropithecus kelyus.

    Science.gov (United States)

    Russo, Gabrielle A

    2016-01-01

    This study evaluated the relationship between the morphology of the sacrum-the sole bony link between the tail or coccyx and the rest of the body-and tail length (including presence/absence) and function using a comparative sample of extant mammals spanning six orders (Primates, Carnivora, Rodentia, Diprotodontia, Pilosa, Scandentia; N = 472). Phylogenetically-informed regression methods were used to assess how tail length varied with respect to 11 external and internal (i.e., trabecular) bony sacral variables with known or suspected biomechanical significance across all mammals, only primates, and only non-primates. Sacral variables were also evaluated for primates assigned to tail categories ('tailless,' 'nonprehensile short-tailed,' 'nonprehensile long-tailed,' and 'prehensile-tailed'). Compared to primates with reduced tail lengths, primates with longer tails generally exhibited sacra having larger caudal neural openings than cranial neural openings, and last sacral vertebrae with more mediolaterally-expanded caudal articular surfaces than cranial articular surfaces, more laterally-expanded transverse processes, more dorsally-projecting spinous processes, and larger caudal articular surface areas. Observations were corroborated by the comparative sample, which showed that shorter-tailed (e.g., Lynx rufus [bobcat]) and longer-tailed (e.g., Acinonyx jubatus [cheetah]) non-primate mammals morphologically converge with shorter-tailed (e.g., Macaca nemestrina) and longer-tailed (e.g., Macaca fascicularis) primates, respectively. 'Prehensile-tailed' primates exhibited last sacral vertebrae with more laterally-expanded transverse processes and greater caudal articular surface areas than 'nonprehensile long-tailed' primates. Internal sacral variables performed poorly compared to external sacral variables in analyses of extant primates, and were thus deemed less useful for making inferences concerning tail length and function in extinct primates. The tails lengths of

  8. Impaired short-term functioning of a benthic community from a deep Norwegian Fjord following deposition of mine tailings and sediments

    NARCIS (Netherlands)

    Mevenkamp, L.; Stratmann, T.; Guilini, K.; Moodley, L.; Van Oevelen, D.; Vanreusel, A.; Westerlund, S.; Sweetman, A.K.

    2017-01-01

    The extraction of minerals from land-based mines necessitates the disposal of large amounts of mine tailings. Dumping and storage of tailings into the marine environment, such as fjords, is currently being performed without knowing the potential ecological consequences. This study investigated the

  9. Uranium mill tailings conditioning technology

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Cokal, E.J.; Wangen, L.E.; Williams, J.M.; O'Brien, P.D.; Thode, E.F.

    1982-01-01

    Conditioning of uranium mill tailings involves the physicochemical alteration of tailings to remove or immobilize mobile radionuclides and toxic trace elements before disposal in a repository. The principal immobilization approach under investigation is sintering tailings at high temperatures (1100-1200 deg. C) to radically alter the structure of tailings. This thermal stabilization at 1200 deg. C reduced radon emanation power for tailings sands by factors of 20 to 200 and for tailings fines by factors of 300 to 1100. Substantial reductions in the leachability of most contaminants have been found for thermally conditioned tailings. Obvious mineral transformations occur, including an increase in amorphous material, the conversion of gypsum to anhydrite and its subsequent decomposition, the disappearance of clay minerals, and some decrease in quartz content. A conceptual thermal stabilization process has been developed wherein obsolete coal-fired rotary cement kilns perform the sintering. An economic analysis of this conceptual process has shown that thermal stabilization can be competitive at certain tailings sites with other remedial actions requiring the excavation, transportation, and burial of tailings in a repository. An analysis of the long-term radiological hazard posed by untreated tailings and by tailings conditioned by radionuclide removal has illustrated the necessity of extracting both 226 Ra and 230 Th to achieve long-term hazard reductions. Sulphuric acid extraction of residual mineral values and important radionuclides from tailings has been investigated. Concentrated H 2 SO 4 can extract up to 80% of the 226 Ra, 70% of the Ba, and 90% of the 230 Th from tailings in a single stage extraction. An economic analysis of a sulphuric acid leach process was made to determine whether the value of minerals recovered from tailings would offset the leaching cost. For one relatively mineral-rich tailings pile, the U and V values would more than pay for the

  10. Uranium tailings bibliography

    International Nuclear Information System (INIS)

    Holoway, C.F.; Goldsmith, W.A.; Eldridge, V.M.

    1975-12-01

    A bibliography containing 1,212 references is presented with its focus on the general problem of reducing human exposure to the radionuclides contained in the tailings from the milling of uranium ore. The references are divided into seven broad categories: uranium tailings pile (problems and perspectives), standards and philosophy, etiology of radiation effects, internal dosimetry and metabolism, environmental transport, background sources of tailings radionuclides, and large-area decontamination

  11. Performance Comparison between Neutralization Tailings and Flotation Tailings Used for Backfill Mix and Mechanism Analysis

    Directory of Open Access Journals (Sweden)

    Bin Han

    2016-01-01

    Full Text Available A comparison test of different tailings used for underground backfill was conducted, using neutralized tailings from BIOX and flotation tailings of Jinfeng Mine. Laboratory comparison test results show that, with neutralized tailings, when the cement dosage is at 19%, backfill UCS after 7 days, 14 days, and 28 days are 105%–163%, 80%–102%, and 33%–43%, respectively, which are higher than those of flotation tailings. When the cement dosage is at 12%, backfill UCS after 7 days, 14 days, and 28 days are 58%–77%, 50%–60%, and 28%–51%, respectively, which are higher than those of flotation tailings. Slurry fluidity of neutralized tailings is lower than that of flotation tailings, while, in these two tailings, the difference of slump and diffusivity values is less than 6%, which is not a significant difference in slurry fluidity. The reason for neutralized tailings showing higher UCS is as follows: during backfill curing, neutralization tailings produce abundant crystals of CaSO4·2H2O in interlaced structure which helps in combining aggregates closely; CaSO4·2H2O hydrates with C3A C4AF contained in the cement and forms clavate cement bacillus which works as a micro reinforcing steel bar. The test proved that neutralized tailings are more optimal for backfilling.

  12. Tailings management at Nabarlek

    International Nuclear Information System (INIS)

    Waggitt, P.

    1989-01-01

    As the entire uranium deposit at Nabarlek was mined in 1979, the mine pit was available as a tailing's repository from the time of commencement of ore processing. In the early years Nabarlek's tailings were deposited subaqueously. In 1985 the tailings deposition method was changed to a sub-aerial, or semi-dry, method. Over the subsequent three years there was evidence that the tailings settled further and squeezed water from lower layers. The water was pumped away and treated for removal of radium before being evaporated in one of the mine's evaporation ponds. When milling was completed in 1988 it was decided to try and increase the rate of water removal and so obtain even greater consolidation of the trailings in a shorter time. This was achieved by loading the tailings with a layer of screened leached sands and waste rock placed on a layer of geotextile filter fabric that had been laid over the whole of the tailings surface in the pit. Once this was completed a modified piling rig was used to insert vertical drains, or wicks, up to 30 metres into the tailings. The drains were placed on a square grid at a spacing of 3.25 metres. Water that was forced out of the tailings by the downward pressure of the sand and rock could flow freely to the surface up these drains. Once at the surface the water was gathered into a sump and pumped away for treatment as before. The drains are working very well at present although it will be some considerable time before the water stops flowing. Already settlement of the tailings is apparent and the settled density of the material is increasing. As far as is known this is the first time that such a system has been employed on mine tailings in a pit in this way

  13. Bioassay for uranium mill tailings

    International Nuclear Information System (INIS)

    Tschaeche, A.N.

    1986-01-01

    Uranium mill tailings are composed of fine sand that contains, among other things, some uranium (U/sup 238/ primarily), and all of the uranium daughters starting with /sup 230/Th that are left behind after the usable uranium is removed in the milling process. Millions of pounds of tailings are and continue to be generated at uranium mills around the United States. Discrete uranium mill tailings piles exist near the mills. In addition, the tailings materials were used in communities situated near mill sites for such purposes as building materials, foundations for buildings, pipe runs, sand boxes, gardens, etc. The Uranium Mill Tailings Remedial Action Project (UMTRAP) is a U.S. Department of Energy Program designed with the intention of removing or stabilizing the mill tailings piles and the tailings used to communities so that individuals are not exposed above the EPA limits established for such tailings materials. This paper discusses the bioassay programs that are established for workers who remove tailings from the communities in which they are placed

  14. Cameco engineered tailings program: linking applied research with industrial processes for improved tailings performance

    International Nuclear Information System (INIS)

    Kotzer, T.G.

    2010-01-01

    'Full text:' Mine tailings at Cameco's operations are by-products of milling uranium ore having variable concentrations of uranium, metals, oxyanions and trace elements or elements of concern (EOC). Cameco has undertaken an Engineered Tailings (ET) program to optimize tailings performance and minimize environmental EOC impacts, regardless of the milled ore source. Applied geochemical and geotechnical tailings research is key within the ET program. In-situ drilling and experimental programs are used to understand long-term tailings behaviour and help validate source term predictions. Within this, the ET program proactively aids in the development of mill-based processes for production of tailings having improved long-term stability. (author)

  15. Heavy tails of OLS

    DEFF Research Database (Denmark)

    Mikosch, Thomas Valentin; de Vries, Casper

    2013-01-01

    Suppose the tails of the noise distribution in a regression exhibit power law behavior. Then the distribution of the OLS regression estimator inherits this tail behavior. This is relevant for regressions involving financial data. We derive explicit finite sample expressions for the tail probabili...

  16. Short interspersed elements (SINEs) from insectivores. Two classes of mammalian SINEs distinguished by A-rich tail structure.

    Science.gov (United States)

    Borodulina, O R; Kramerov, D A

    2001-10-01

    Four tRNA-related SINE families were isolated from the genome of the shrew Sorex araneus (SOR element), mole Mogera robusta (TAL element), and hedgehog Mesechinus dauuricus (ERI-1 and ERI-2 elements). Each of these SINEs families is specific for a single Insectivora family: SOR, for Soricidae (shrews); TAL, for Talpidae (moles and desmans); ERI-1 and ERI-2, for Erinaceidae (hedgehogs). There is a long polypyrimidine region (TC-motif) in TAL, ERI-1, and ERI-2 elements located immediately upstream of an A-rich tail with polyadenylation signals (AATAAA) and an RNA polymerase III terminator (T(4-6)) or TCT(3-4)). Ten out of 14 analyzed mammalian tRNA-related SINE families have an A-rich tail similar to that of TAL, ERI-1, and ERI-2 elements. These elements were assigned to class T+. The other four SINEs including SOR element have no polyadenylation signal and transcription terminator in their A-rich tail and were assigned to class T-. Class T+ SINEs occur only in mammals, and most of them have a long polypyrimidine region. Possible models of retroposition of class T+ and T- SINEs are discussed.

  17. Prevalence and site specificity of Sarcocystis greineri sarcocysts in Virginia opossum (Didelphis virginiana) in Florida.

    Science.gov (United States)

    Baird, K L; Cheadle, M A; Greiner, E C

    2002-06-01

    Sarcocysts of Sarcocystis greineri in the Virginia opossum (Didelphis virginiana) were observed for documenting sarcocyst prevalence, seasonal prevalence, and muscle specificity. Characteristics of sarcocysts found in striated muscle were recorded, as were light microscopy measurements. Overall prevalence of sarcocysts in striated muscle was 10.0% (24/240). No statistical difference (P = 0.156) in prevalence was detected between summer (13.1%; 16/122) and fall (6.7%; 8/118). Sarcocysts were found in muscles of the diaphragm, leg, breast, tongue, back, and esophagus. Diaphragm had the highest specificity of 72.7% (8/11), which was significantly different (P = 0.05) when compared with tongue and esophagus at 16.6% (1/6). Breast and leg muscle had a specificity of sarcocysts of 54.5% (6/11), whereas 27.2% (3/11) of back muscles contained sarcocysts.

  18. Tailings neutralization and other alternatives for immobilizing toxic materials in tailings. Final report

    International Nuclear Information System (INIS)

    Opitz, B.E.; Sherwood, D.R.; Dodson, M.E.; Serne, R.J.

    1985-09-01

    This document, ''Tailing Neutralization and Other Alternatives for Immobilizing Toxic Materials in Tailings,'' is the final report in a series of six. It summarizes research completed since the beginning of the project. Three subtasks are included: Subtask A - Neutralization Methods Selection; Subtask B - Laboratory Analysis; and Subtask C - Field Testing. Subtask A reviews treatment processes from other industries to evaluate whether current waste technology from other fields is applicable to the uranium industry. This task also identifies several reagents that were tested for their effectiveness in treating acidic tailings and tailings solution in order to immobilize the contaminants associated with the acid waste. Subtask B describes the laboratory batch and column treatment studies performed on solid waste tailings and tailings solutions over the course of the project. The evaluation of several reagents identified in Subtask A was based on three criteria: (1) treated effluent water quality; (2) neutralized sludge handling and hydraulic properties; and (3) reagent costs and acid neutralizing efficiency. Subtask C presents a field demonstration plan that will evaluate the effectiveness, costs, and benefits of neutralizing acidic uranium mill tailings solution to reduce the potential leaching of toxic trace metals, radionuclides, and macro ions from a tailings impoundment. Details of the related research can be found in the documents listed in the ''Previous Documents in Series.'' 43 refs., 9 figs., 46 tabs

  19. Lateral movements of a massive tail influence gecko locomotion: an integrative study comparing tail restriction and autotomy.

    Science.gov (United States)

    Jagnandan, Kevin; Higham, Timothy E

    2017-09-07

    Tails are an intricate component of the locomotor system for many vertebrates. Leopard geckos (Eublepharis macularius) possess a large tail that is laterally undulated during steady locomotion. However, the tail is readily shed via autotomy, resulting in the loss of tail function, loss in body mass, and a cranial shift in the center of mass. To elucidate the function of tail undulations, we investigated changes in limb kinematics after manipulating the tail artificially by restricting tail undulations and naturally by removing the tail via autotomy. Restricting tail undulations resulted in kinematic adjustments similar to those that occur following tail autotomy, characterized by more flexed hind limb joints. These data suggest that effects of autotomy on locomotion may be linked to the loss of tail movements rather than the loss of mass or a shift in center of mass. We also provide empirical support for the link between lateral tail undulations and step length through the rotation of the pelvic girdle and retraction of the femur. Restriction and autotomy of the tail limits pelvic rotation, which reduces femur retraction and decreases step length. Our findings demonstrate a functional role for tail undulations in geckos, which likely applies to other terrestrial vertebrates.

  20. Rescue of axotomized rubrospinal neurons by brain-derived neurotrophic factor (BDNF) in the developing opossum, Didelphis virginiana.

    Science.gov (United States)

    Wang, X M; Terman, J R; Martin, G F

    1999-12-10

    Many rubrospinal neurons die in developing opossums when their axon is cut at thoracic levels of the spinal cord and in the present study we asked whether they can be rescued by brain-derived neurotrophic factor (BDNF). Bilateral injections of Fast Blue (FB) were made into the rostral lumbar cord to prelabel rubrospinal neurons and 5 days later the rubrospinal tract was cut unilaterally by hemisecting the thoracic cord. Immediately after hemisection, BDNF-soaked gelfoam was placed into the lesion cavity. Since pilot data indicated that one application of BDNF was not sufficient to produce a rescue effect, a second application was made 7 days later. Seven days after the second application the pups were killed by an overdose of anesthetic so that the red nucleus contralateral and ipsilateral to the lesion site could be examined for labeled neurons. The rubrospinal tract is almost entirely crossed, so the red nucleus contralateral to the lesion contained many axotomized neurons, whereas the red nucleus ipsilateral to it did not. Age-matched controls were subjected to the same procedures, but the gelfoam applied to the lesion site in the experimental animals was soaked only in the vehicle used to deliver BDNF. In all cases, labeled neurons were fewer in number in the red nucleus contralateral to the lesion than ipsilateral to it. It was of particular interest, however, that labeled neurons contralateral to the lesion were more numerous in the animals treated with BDNF than in the controls. We conclude that BDNF rescues at least some rubrospinal neurons from axotomy-induced cell death in developing opossums suggesting that loss of access to BDNF, and perhaps other neurotrophins, contributes to failure of rubrospinal neurons to survive axotomy.

  1. Purification of Sarcocystis neurona sporocysts from opossum (Didelphis virginiana) using potassium bromide discontinuous density gradient centrifugation.

    Science.gov (United States)

    Elsheikha, Hany M; Murphy, Alice J; Fitzgerald, Scott D; Mansfield, Linda S; Massey, Jeffrey P; Saeed, Mahdi A

    2003-06-01

    This report describes a new, inexpensive procedure for the rapid and efficient purification of Sarcocystis neurona sporocysts from opossum small intestine. S. neurona sporocysts were purified using a discontinuous potassium bromide density gradient. The procedure provides a source of sporocyst wall and sporozoites required for reliable biochemical characterization and for immunological studies directed at characterizing antigens responsible for immunological responses by the host. The examined isolates were identified as S. neurona using random amplified polymorphic DNA primers and restriction endonuclease digestion assays. This method allows the collection of large numbers of highly purified S. neurona sporocysts without loss of sporocyst viability as indicated by propidium iodide permeability and cell culture infectivity assays. In addition, this technique might also be used for sporocyst purification of other Sarcocystis spp.

  2. Injurious tail biting in pigs

    DEFF Research Database (Denmark)

    D'Eath, R.B.; Amott, G.; Turner, S. P.

    2014-01-01

    not allow tail docking at all. Against this background, using a novel approach focusing on research where tail injuries were quantified, we review the measures that can be used to control tail biting in pigs without tail docking. Using this strict criterion, there was good evidence that manipulable...... substrates and feeder space affect damaging tail biting. Only epidemiological evidence was available for effects of temperature and season, and the effect of stocking density was unclear. Studies suggest that group size has little effect, and the effects of nutrition, disease and breed require further...... underlying processes of tail biting. A quantitative comparison of the efficacy of different methods of provision of manipulable materials, and a review of current practices in countries and assurance schemes where tail docking is banned, both suggest that daily provision of small quantities of destructible...

  3. Lateral movements of a massive tail influence gecko locomotion: an integrative study comparing tail restriction and autotomy

    OpenAIRE

    Jagnandan, Kevin; Higham, Timothy E.

    2017-01-01

    Tails are an intricate component of the locomotor system for many vertebrates. Leopard geckos (Eublepharis macularius) possess a large tail that is laterally undulated during steady locomotion. However, the tail is readily shed via autotomy, resulting in the loss of tail function, loss in body mass, and a cranial shift in the center of mass. To elucidate the function of tail undulations, we investigated changes in limb kinematics after manipulating the tail artificially by restricting tail un...

  4. Origin, course, and laterality of spinocerebellar axons in the North American opossum, Didelphis virginiana.

    Science.gov (United States)

    Terman, J R; Wang, X M; Martin, G F

    1998-08-01

    Spinocerebellar axons have been studied extensively in placental mammals, but there have been no full reports on their origin, laterality, or spinal course in any marsupial. We have used the North American opossum (Didelphis virginiana) to obtain such information and to ask whether any spinocerebellar neurons innervate both the anterior and posterior lobes of the cerebellum through axonal collaterals. To identify spinal neurons that project to the cerebellum, we employed the retrograde transport of Fluoro-Gold (FG) from the anterior lobe, the main target of spinocerebellar axons. In some cases, cerebellar injections of FG were combined with hemisections of the rostral cervical or midthoracic spinal cord, so that laterality of spinocerebellar connections could be established. To determine whether single neurons project to both the anterior lobe and the posterior lobe, injections of Fast Blue (FB) into the anterior lobe were combined with injections of Diamidino yellow (DY) or rhodamine B dextran (RBD) into the posterior lobe, or vice versa. Following injections of FG into the anterior lobe, neurons were labeled throughout the length of the spinal cord, which differed in laminar distribution and laterality of their projections. Among other areas, neurons were labeled in the central cervical nucleus, the nucleus centrobasalis, Clarke's nucleus, the dorsal horn dorsal spinocerebellar tract area, the spinal border region, and Stilling's nucleus. When anterior lobe injections of FB were combined with injections of RBD or DY into the posterior lobe, or vice versa, some double-labeled neurons were present in all major spinocerebellar groups. Cerebellar injections of FG also retrogradely labeled spinocerebellar axons, allowing us to document their locations in the gray matter as well as within the periphery of the lateral and ventral funiculi at all spinal levels. A few spinocerebellar axons also were found in the dorsal funiculus (a dorsal column-spinocerebellar tract

  5. Tree-Substrate Water Relations and Root Development in Tree Plantations Used for Mine Tailings Reclamation.

    Science.gov (United States)

    Guittonny-Larchevêque, Marie; Bussière, Bruno; Pednault, Carl

    2016-05-01

    Tree water uptake relies on well-developed root systems. However, mine wastes can restrict root growth, in particular metalliferous mill tailings, which consist of the finely crushed ore that remains after valuable metals are removed. Thus, water stress could limit plantation success in reclaimed mine lands. This study evaluates the effect of substrates varying in quality (topsoil, overburden, compost and tailings mixture, and tailings alone) and quantity (50- or 20-cm-thick topsoil layer vs. 1-m plantation holes) on root development and water stress exposure of trees planted in low-sulfide mine tailings under boreal conditions. A field experiment was conducted over 2 yr with two tree species: basket willow ( L.) and hybrid poplar ( Moench × A. Henry). Trees developed roots in the tailings underlying the soil treatments despite tailings' low macroporosity. However, almost no root development occurred in tailings underlying a compost and tailings mixture. Because root development and associated water uptake was not limited to the soil, soil volume influenced neither short-term (water potential and instantaneous transpiration) nor long-term (δC) water stress exposure in trees. However, trees were larger and had greater total leaf area when grown in thicker topsoil. Despite a volumetric water content that always remained above permanent wilting point in the tailings colonized by tree roots, measured foliar water potentials at midday were lower than drought thresholds reported for both tested tree species. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. Skeletal lesions in a population of Virginia opossums (Didelphis virginiana) from Baldwin County, Georgia.

    Science.gov (United States)

    Mead, Alfred J; Patterson, David B

    2009-04-01

    Antemortem skeletal lesions were analyzed in 61 Virginia opossums (Didelphis virginiana) collected as roadkill from Baldwin County, Georgia, USA. As evidenced by bridging fracture calluses, misalignments, bone-surface depressions, perforations, localized superficial calluses, periosteal proliferations, and bony bridges across intervertebral disk spaces, 64% of the individuals had signs of one or more healed injuries. Within the subset of skeletons with bone lesions, 54% had healed rib fractures and 23% had scapular, 21% pelvic, 18% fibular, 18% vertebral, 13% dentary, 10% tibial, and 10% podial lesions. Bone lesions occurred most frequently in the cranial portion of the skeletons and averaged approximately four per individual. The majority of the skeletal injuries appeared to be inconsistent with those caused by falls or automobile collisions. The nature and position of the bone lesions suggested that nonfatal predator attacks, possibly from domestic dogs, may be a significant contributor to bodily injury in this species.

  7. Orphan Stars Found in Long Galaxy Tail

    Science.gov (United States)

    2007-09-01

    ESO 137-001 and Tail in Abell 3627 H-alpha Image of ESO 137-001 and Tail in Abell 3627 "By our galactic standards, these are extremely lonely stars," said Mark Voit, another team member from MSU. "If life was to form out there on a planet a few billion years from now, they would have very dark skies." The gas that formed the orphan stars was stripped out of its parent galaxy by the pressure induced by the motion of the galaxy through the multimillion degree gas that pervades the intergalactic space of the galaxy cluster. Eventually most of the gas will be scoured from the galaxy, depleting the raw material for new stars, and effectively stopping further star formation in the galaxy. This process may represent an important but short-lived stage in the transformation of a galaxy. Although apparently rare in the present-day universe, galactic tails of gas and orphan stars may have been more common billions of years ago when galaxies were younger and richer in star-forming gas. These results will appear in the December 10th issue of The Astrophysical Journal. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. The SOAR (Southern Astrophysical Research Telescope) is a joint project of Michigan State University, Conselho Nacional de Pesquisas Científicas e Tecnológicas (CNPq-Brazil), The University of North Carolina at Chapel Hill, and the National Optical Astronomy Observatory.

  8. Performance Comparison between Neutralization Tailings and Flotation Tailings Used for Backfill Mix and Mechanism Analysis

    OpenAIRE

    Han, Bin; Sun, Wei; Yu, Shaofeng; Liu, Chao; Yao, Song; Wu, Jianxun

    2016-01-01

    A comparison test of different tailings used for underground backfill was conducted, using neutralized tailings from BIOX and flotation tailings of Jinfeng Mine. Laboratory comparison test results show that, with neutralized tailings, when the cement dosage is at 19%, backfill UCS after 7 days, 14 days, and 28 days are 105%–163%, 80%–102%, and 33%–43%, respectively, which are higher than those of flotation tailings. When the cement dosage is at 12%, backfill UCS after 7 days, 14 days, and 28 ...

  9. Frost evolution in tailings

    International Nuclear Information System (INIS)

    1991-04-01

    A review was carried out on the physical and thermal mechanisms of permafrost evaluation in soils and uranium tailings. The primary mechanism controlling permafrost evolution is conductive heat transfer with the latent heat of fusion of water being liberated as phase change occurs. Depending on the soil properties and freezing rate, pore water can be expelled from the frost front or pore water can migrate towards the frost front. Solute redistribution may occur as the frost front penetrates into the soil. The rate of frost penetration is a function of the thermal properties of the tailings and the climatic conditions. Computer modelling programmes capable of modelling permafrost evolution were reviewed. The GEOTHERM programme was selected as being the most appropriate for this study. The GEOTHERM programme uses the finite element method of thermal analysis. The ground surface temperature is determined by solving the energy balance equations a the ground surface. The GEOTHERM programme was used to simulate the permafrost evolution in the Key Lake Mine tailings located in north central Saskatchewan. The analyses indicated that the existing frozen zones in the tailing pond will eventually thaw if an average snow depth covers the tailings. Hundreds of years are required to thaw the tailings. If minimal snow cover is present the extent of the frozen zone in the tailings will increase

  10. Characterization of oils sands thickened tailings

    Energy Technology Data Exchange (ETDEWEB)

    Scott, J.D.; Jeeravipoolvarn, S.; Donahue, R.; Ozum, B. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2008-07-01

    This presentation discussed the characterization of oils sands thickened tailings. The problem statement was defined as the fact that many laboratory procedures to characterize fine tailings do not take into account the extraction process, and instead use standardized laboratory tests. The purpose of this presentation was to demonstrate how different extraction processes affect the fine tailings geotechnical properties and water chemistry. Properties that were characterized included particle size analysis from hydrometer-sieve tests; per cent clay from methylene blue tests; per cent clay from mineralogy tests; Atterberg limits; water chemistry; and morphology by scanning electron microscopy. The presentation discussed the origin of fines (silt and clay) in tailings; where fine particles come from; tailings materials; mineralogy of tailings; the hydrometer-sieve test on fine tailings and thickened tailings; and the methylene blue test. It was concluded that the great majority of clay minerals in the tailings come from the clay-shale discontinuous seams and layers. For thickened tailings, the dispersed and non-dispersed hydrometer tests show considerable difference in the amount of clay size material. tabs., figs.

  11. Citizen knowledge and perception of black-tailed prairie dog management: Report to respondents

    Science.gov (United States)

    Sexton, Natalie R.; Brinson, Ayeisha; Ponds, Phadrea D.; Cline, Kurt; Lamb, Berton L.

    2001-01-01

    What do citizens know about black-tailed prairie dogs, and where do they get their information? When management decisions need to be made regarding an animal such as the black-tailed prairie dog, an understanding of the species and its relationship to humans is necessary. This includes knowing the biology of the animal, where it lives, and how it interacts with other animals. But it is equally important for those making decisions about the species to understand citizens’ knowledge and perceptions so managers can effectively communicate with the public and help the public participate in planning and decision making activities. Unfortunately, what is known about public knowledge, perception, and preferences concerning prairie dog management is limited to data from only a few areas. This study attempts to answer the question: What do people in the short-grass prairie region of the United States know and think about black-tailed prairie dogs?

  12. Electro-remediation of copper mine tailings. Comparing copper removal efficiencies for two tailings of different age

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Lamas, Victor; Gutierrez, Claudia

    2013-01-01

    This work compares and evaluates the copper removal efficiency when applying electric fields to two mine tailings originating from the same mine but of different age. Eight experiments were carried out - four on tailings deposited more than 20 years ago (old tailings) and four on tailings deposit...

  13. Uranium mill tailings management

    International Nuclear Information System (INIS)

    1982-01-01

    Facilities for the disposal of uranium mill tailings will invariably be subjected to geomorphological and climatological influences in the long-term. Proceedings of a workshop discuss how the principles of geomorphology can be applied to the siting, design, construction, decommissioning and rehabilitation of disposal facilities in order to provide for long-term containment and stability of tailings. The characteristics of tailings and their behaviour after disposal influence the potential impacts which might occur in the long-term. Proceedings of another workshop examine the technologies for uranium ore processing and tailings conditioning with a view to identifying improvements that could be made in such characteristics

  14. Mine tailings disposal

    International Nuclear Information System (INIS)

    Gonzales, P.A.; Adams, B.J.

    1980-06-01

    The hydrologic evaluation of mine tailings disposal sites after they are abandoned is considered in relation to their potential environmental impact on a long term basis. There is a direct relation between the amounts and types of water leaving a disposal site and the severity of the potential damage to the environment. The evaluation of the relative distribution of the precipitation reaching the ground into evaporation, runoff and infiltration is obtained for a selected site and type of tailings material whose characteristics and physical properties were determined in the soils laboratory. A conceptual model of the hydrologic processes involved and the corresponding mathematical model were developed to simulate the physical system. A computer program was written to solve the set of equations forming the mathematical model, considering the physical properties of the tailings and the rainfall data selected. The results indicate that the relative distribution of the precipitation depends on the surface and upper layer of the tailings and that the position of the groundwater table is governed by the flow through the bottom of the profile considered. The slope of the surface of the mass of tailings was found to be one of the principal factors affecting the relative distribution of precipitation and, therefore, the potential pollution of the environment

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

    Energy Technology Data Exchange (ETDEWEB)

    Knierman, Karen A.; Scowen, Paul; Veach, Todd; Groppi, Christopher [School of Earth and Space Exploration, Arizona State University, 550 E. Tyler Mall, Room PSF-686 (P.O. Box 871404), Tempe, AZ 85287-1404 (United States); Mullan, Brendan; Charlton, Jane [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA (United States); Konstantopoulos, Iraklis [Australian Astronomical Observatory, P.O. Box 915, North Ryde NSW 1670 (Australia); Knezek, Patricia M., E-mail: karen.knierman@asu.edu, E-mail: paul.scowen@asu.edu, E-mail: tveach@asu.edu, E-mail: cgroppi@asu.edu, E-mail: mullan@astro.psu.edu, E-mail: iraklis@aao.gov.au, E-mail: pknezek@noao.edu [WIYN Consortium, Inc., 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)

    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 the 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.

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

    International Nuclear Information System (INIS)

    Knierman, Karen A.; Scowen, Paul; Veach, Todd; Groppi, Christopher; Mullan, Brendan; Charlton, Jane; Konstantopoulos, Iraklis; Knezek, Patricia M.

    2013-01-01

    The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio ∼4: 1 occurring ∼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 Hα 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 μm [C II] emission at the location of the three most luminous Hα sources in the eastern tail, but not at the location of the even brighter Hα 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

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

    International Nuclear Information System (INIS)

    Zhang, B.; Lin, X. B.; Kong, X.; Sun, M.; Ji, L.; Sarazin, C.; Nulsen, P. E. J.; Forman, W.; Jones, C.; Roediger, E.; Donahue, M.; Voit, G. M.

    2013-01-01

    We present the analysis of a deep Chandra observation of a ∼2 L * 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. Spectral 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 implications are

  18. Tailings management best practice: a case study of the McClean Lake JEB Tailings Management Facility

    International Nuclear Information System (INIS)

    Tremblay, M.A.J.; Rowson, J.

    2005-01-01

    COGEMA Resources Inc. (which is part of the Areva Group) is a Canadian company with its head office in Saskatoon, Saskatchewan. It owns and operates mining and milling facilities in Northern Saskatchewan, which produce uranium concentrate. McClean Lake Operation commenced production in 1999 and its tailings management facility represents the state of the art for tailings management in the uranium industry in Canada. Tailings disposal has the potential to cause effects in the surrounding receiving environment primarily through migration of soluble constituents from the facility to surface water receptors. In-pit disposal or mill tailings has become the standard in the uranium mining industry in Northern Saskatchewan. This method or tailings management demonstrates advances in terms of worker radiation protection and containment of soluble constituents both during operations and into the long term. Sub-aqueous deposition of tailings protects personnel from exposure to radiation and airborne emissions and prevents freezing of tailings, which can hinder consolidation. The continuous inflow of groundwater to the facility is achieved during operations, through control of water levels within the facility. This ensures hydrodynamic containment, which prevents migration of soluble radionuclides and heavy metals into the surrounding aquifer during operations. The environmental performance of the decommissioned facility depends upon the rate of release of contaminants to the receiving environment. The rate of constituent loading to the receiving environment will ultimately be governed by the concentrations of soluble constituents within the tailings mass, the mechanisms for release from the tailings to the surrounding groundwater system, and transport of constituents within the groundwater pathway to the receiving environment. The tailings preparation process was designed to convert arsenic into a stable form to reduce soluble concentrations within the tailings mass. The

  19. Settlement of uranium mill tailings

    International Nuclear Information System (INIS)

    Chen, P.K.; Guros, F.B.; Keshian, B.

    1988-01-01

    Two test embankments were constructed on top of an old tailings deposit near Ambrosia Lake, New Mexico to determine settlement characteristics of hydraulically- deposited uranium mill tailings. Before construction of the embankments, properties of in-situ tailings and foundation soils were determined using data from boreholes, piezocone soundings, and laboratory tests. These properties were used to estimate post-construction settlement of a planned disposal embankment to be constructed on the tailings. However, excessive uncertainty existed in the following: field settlement rates of saturated and unsaturated tailings, degree of preconsolidation of the upper 15 feet of tailings, and the ability of an underlying silty sand foundation layer to facilitate drainage. Thus, assurance could not be provided that differential settlements of the radon barrier and erosion protection layers would be within allowable limits should the planned disposal embankment be constructed in a single-stage

  20. Attitudes of Dutch Pig Farmers Towards Tail Biting and Tail Docking

    NARCIS (Netherlands)

    Bracke, M.B.M.; Lauwere, de C.C.; Wind, S.M.M.; Zonderland, J.J.

    2013-01-01

    The Dutch policy objective of a fully sustainable livestock sector without mutilations by 2023 is not compatible with the routine practice of tail docking to minimize the risk of tail biting. To examine farmer attitudes towards docking, a telephone survey was conducted among 487 conventional and 33

  1. Anothor Trypanosoma, distinct from T. cruzi, multiplies in the lumen of the anal glands the opossum Didelphis marsupialis

    Directory of Open Access Journals (Sweden)

    Maria P. Deane

    1986-03-01

    Full Text Available Epimastigotes were found multiplying in the anal glands and in hemocultures of an opossum; rare metacyclics were seen in the cultures. The flagellate is possibly T. (Megatrypanum freitasi Rego, Magalhães & Siqueira, 1957, but its final identification is still pending.Um tripanosoma ainda não identificado foi encontrado multiplicando-se como epimastigotas extracelulares na glândulas anais de um gambá. Trata-se possivelmente do T. (M. freitasi. O achado demonstra que tal localização não se restringe ao T. cruzi e sugere que os tripanosomatídeos devem ser buscados nesta e em outras situações inortodoxas, no organismo dos hospedeiros vertebrados.

  2. Tail-weighted dependence measures with limit being the tail dependence coefficient

    KAUST Repository

    Lee, David

    2017-12-02

    For bivariate continuous data, measures of monotonic dependence are based on the rank transformations of the two variables. For bivariate extreme value copulas, there is a family of estimators (Formula presented.), for (Formula presented.), of the extremal coefficient, based on a transform of the absolute difference of the α power of the ranks. In the case of general bivariate copulas, we obtain the probability limit (Formula presented.) of (Formula presented.) as the sample size goes to infinity and show that (i) (Formula presented.) for (Formula presented.) is a measure of central dependence with properties similar to Kendall\\'s tau and Spearman\\'s rank correlation, (ii) (Formula presented.) is a tail-weighted dependence measure for large α, and (iii) the limit as (Formula presented.) is the upper tail dependence coefficient. We obtain asymptotic properties for the rank-based measure (Formula presented.) and estimate tail dependence coefficients through extrapolation on (Formula presented.). A data example illustrates the use of the new dependence measures for tail inference.

  3. Tail-weighted dependence measures with limit being the tail dependence coefficient

    KAUST Repository

    Lee, David; Joe, Harry; Krupskii, Pavel

    2017-01-01

    For bivariate continuous data, measures of monotonic dependence are based on the rank transformations of the two variables. For bivariate extreme value copulas, there is a family of estimators (Formula presented.), for (Formula presented.), of the extremal coefficient, based on a transform of the absolute difference of the α power of the ranks. In the case of general bivariate copulas, we obtain the probability limit (Formula presented.) of (Formula presented.) as the sample size goes to infinity and show that (i) (Formula presented.) for (Formula presented.) is a measure of central dependence with properties similar to Kendall's tau and Spearman's rank correlation, (ii) (Formula presented.) is a tail-weighted dependence measure for large α, and (iii) the limit as (Formula presented.) is the upper tail dependence coefficient. We obtain asymptotic properties for the rank-based measure (Formula presented.) and estimate tail dependence coefficients through extrapolation on (Formula presented.). A data example illustrates the use of the new dependence measures for tail inference.

  4. Copper tailings in stucco mortars

    Directory of Open Access Journals (Sweden)

    Osvaldo Pavez

    Full Text Available Abstract This investigation addressed the evaluation of the use of copper tailings in the construction industry in order to reduce the impact on the environment. The evaluation was performed by a technical comparison between stucco mortars prepared with crushed conventional sand and with copper tailings sand. The best results were achieved with the stucco mortars containing tailings. The tailings presented a fine particles size distribution curve different from that suggested by the standard. The values of compressive strength, retentivity, and adherence in the stucco mortars prepared with copper tailings were much higher than those obtained with crushed sand. According to the results from this study, it can be concluded that the preparation of stucco mortars using copper tailings replacing conventional sand is a technically feasible alternative for the construction industry, presenting the benefit of mitigating the impact of disposal to the environment.

  5. Controlled chaos: three-dimensional kinematics, fiber histochemistry, and muscle contractile dynamics of autotomized lizard tails.

    Science.gov (United States)

    Higham, Timothy E; Lipsett, Kathryn R; Syme, Douglas A; Russell, Anthony P

    2013-01-01

    The ability to shed an appendage occurs in both vertebrates and invertebrates, often as a tactic to avoid predation. The tails of lizards, unlike most autotomized body parts of animals, exhibit complex and vigorous movements once disconnected from the body. Despite the near ubiquity of autotomy across groups of lizards and the fact that this is an extraordinary event involving the self-severing of the spinal cord, our understanding of why and how tails move as they do following autotomy is sparse. We herein explore the histochemistry and physiology of the tail muscles of the leopard gecko (Eublepharis macularius), a species that exhibits vigorous and variable tail movements following autotomy. To confirm that the previously studied tail movements of this species are generally representative of geckos and therefore suitable for in-depth muscle studies, we quantified the three-dimensional kinematics of autotomized tails in three additional species. The movements of the tails of all species were generally similar and included jumps, flips, and swings. Our preliminary analyses suggest that some species of gecko exhibit short but high-frequency movements, whereas others exhibit larger-amplitude but lower-frequency movements. We then compared the ATPase and oxidative capacity of muscle fibers and contractile dynamics of isolated muscle bundles from original tails, muscle from regenerate tails, and fast fibers from an upper limb muscle (iliofibularis) of the leopard gecko. Histochemical analysis revealed that more than 90% of the fibers in original and regenerate caudal muscles had high ATPase but possessed a superficial layer of fibers with low ATPase and high oxidative capacity. We found that contraction kinetics, isometric force, work, power output, and the oscillation frequency at which maximum power was generated were lowest in the original tail, followed by the regenerate tail and then the fast fibers of the iliofibularis. Muscle from the original tail exhibited

  6. Research on Long Tail Recommendation Algorithm

    Science.gov (United States)

    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.

  7. An Analysis of the Effects of Wing Aspect Ratio and Tail Location on Static Longitudinal Stability Below the Mach Number of Lift Divergence

    Science.gov (United States)

    Axelson, John A.; Crown, J. Conrad

    1948-01-01

    An analysis is presented of the influence of wing aspect ratio and tail location on the effects of compressibility upon static longitudinal stability. The investigation showed that the use of reduced wing aspect ratios or short tail lengths leads to serious reductions in high-speed stability and the possibility of high-speed instability.

  8. The impact of tail tip amputation and ink tattoo on C57BL/6JBomTac mice.

    Science.gov (United States)

    Sørensen, Dorte Bratbo; Stub, Charlotte; Jensen, Henrik Elvang; Ritskes-Hoitinga, Merel; Hjorth, Peter; Ottesen, Jan Lund; Hansen, Axel Kornerup

    2007-01-01

    Genetic material for polymerase chain reaction (PCR) and Southern blot analysis on transgenic mice is normally obtained by tail biopsy. Additionally, it may be necessary to tattoo the mice, as it is essential to have a good and permanent identification. The aim of this study was to evaluate the effects of amputating the tip of the tail to obtain a biopsy for genetic analysis and of ink tattooing on welfare in C57BL/6J mice, a strain often used as genetic background for transgenes. The behaviour of the animals, fluctuating asymmetry (FA, a measure of developmental instability) and the level of restitution in the remaining part of the tail were evaluated and used for an assessment of the impact of these procedures on the welfare of the animals. One group of mice was marked by tail tattooing at various ages. Another group of mice were tail amputated at 12 or 20 days of age. Body weight and FA were followed, and at the end of the experiment, the level of fear/anxiety was assessed using a light-dark box. In the group of tail-amputated animals observation of climbing behaviour and a beam walking test for balance was performed. Seven weeks after tail amputation, the animals were euthanized. The remaining part of the tail was evaluated histopathologically. Body weight, behaviour in the light-dark box and balance test results were not influenced by tail amputation or tattooing. FA was only transiently increased by tattooing. Climbing behaviour was reduced just after tail amputation at 20 days of age. No signs of neuromas were found in the amputated tails, but seven weeks after amputation a significant number of mice did not have fully regenerated glandular tissue and hair follicles in the tail. It is concluded that both tail amputation and tail tattooing seem to have minor short-term negative effects on welfare and that the tissues on the tail probably do not regenerate fully after amputation.

  9. Tail Asymptotics for the Sum of two Heavy-tailed Dependent Risks

    DEFF Research Database (Denmark)

    Albrecher, H.; Asmussen, Søren

    Let X1,X2 denote positive exchangable heavy-tailed random variables with continuous marginal distribution function F. The asymptotic behavior of the tail of X1 + X2 is studied in a general copula framework and some bounds and extremal properties are provided. For more specific assumptions on F...

  10. Environmental assessment of remedial action at the Gunnison Uranium Mill Tailings Site, Gunnison, Colorado

    International Nuclear Information System (INIS)

    Bachrach, A.; Hoopes, J.; Morycz, D.; Bone, M.; Cox, S.; Jones, D.; Lechel, D.; Meyer, C.; Nelson, M.; Peel, R.; Portillo, R.; Rogers, L.; Taber, B.; Zelle, P.; Rice, G.

    1984-12-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the Gunnison uranium of mill tailings site located 0.5 miles south of Gunnison, Colorado. The site covers 56 acres and contains 35 acres of tailings, 2 of the original mill buildings and a water tower. The Uranium Mill Tailings Radiation Control of Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated [vicinity] properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR 192). Remedial actions must be performed in accordance with these standards and with the occurrence of the Nuclear Regulatory Commission. Four alternatives have been addressed in this document. The first alternative is to consolidate the tailings and associated contaminated soils into a recontoured pile on the southern portion of the existing site. A radon barrier of silty clay would be constructed over the pile and various erosion control measures would be taken to assure the long-term integrity of the pile. Two other alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives generally involve greater short-term impacts and are more costly but would result in the tailings being stabilized in a location farther from the city of Gunnison. The no action alternative is also assessed

  11. Runaway tails in magnetized plasmas

    Science.gov (United States)

    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.

  12. Will Culling White-Tailed Deer Prevent Lyme Disease?

    Science.gov (United States)

    Kugeler, K J; Jordan, R A; Schulze, T L; Griffith, K S; Mead, P S

    2016-08-01

    White-tailed deer play an important role in the ecology of Lyme disease. In the United States, where the incidence and geographic range of Lyme disease continue to increase, reduction of white-tailed deer populations has been proposed as a means of preventing human illness. The effectiveness of this politically sensitive prevention method is poorly understood. We summarize and evaluate available evidence regarding the effect of deer reduction on vector tick abundance and human disease incidence. Elimination of deer from islands and other isolated settings can have a substantial impact on the reproduction of blacklegged ticks, while reduction short of complete elimination has yielded mixed results. To date, most studies have been conducted in ecologic situations that are not representative to the vast majority of areas with high human Lyme disease risk. Robust evidence linking deer control to reduced human Lyme disease risk is lacking. Currently, there is insufficient evidence to recommend deer population reduction as a Lyme disease prevention measure, except in specific ecologic circumstances. © 2015 Blackwell Verlag GmbH.

  13. Development of the eye in the North American opossum (Didelphis virginiana).

    Science.gov (United States)

    McMenamin, P G; Krause, W J

    1993-01-01

    Marsupials are unique models for developmental biology-oriented research because of the immature state of their development at birth. The North American opossum (Didelphis virginiana) has several advantages over other marsupials, including large litter size, short prenatal period (12.5 d), an extended postnatal period while accessible in the pouch, and its ability to reproduce reliably in captivity. Studies of ocular development in this species have not been reported previously. The aim of the present investigation was therefore to document the major landmarks in prenatal and postnatal development of the cornea, lens, iris, ciliary body and retina. Fifteen embryos (10.5, 10.7 and 11 d postconception and 6 h after birth [12 d]) were studied by paraffin histology. Eyes of pouch young at 8 d, 2, 6, 9 and 13 wk were studied by transmission electron microscopy and light microscopy. The study revealed a similar pattern of ocular development in Didelphis to other metatherian and eutherian mammals. Differentiation of the eye is particularly rapid in the 2 d before birth. For example, although the lens vesicle separates from the surface ectoderm on d 10, by birth (2.5 d later) a primitive cornea and fused eyelids have formed, presumably to protect the eye during migration to the pouch. At birth the retinal pigment epithelium (RPE) contains melanin; however, the inner layer of the optic cup does not differentiate into an inner and outer neuroblastic layer until 8 d after birth. Around 6 wk after birth most components of the adult eye are identifiable, albeit in an immature form. These include the corneal layers, the iris (including the sphincter pupillae), ciliary processes, RPE tapetum, and a fully laminated retina with immature photoreceptors. A knowledge of the timing of major events in eye development in Didelphis and their comparison with equivalent events in human eye development should allow the appropriate choice of stages for any future experimental studies

  14. Radiological survey of the inactive uranium-mill tailings at the Spook site, Converse County, Wyoming

    International Nuclear Information System (INIS)

    Haywood, F.F.; Christian, D.J.; Chou, K.D.; Ellis, B.S.; Lorenzo, D.; Shinpaugh, W.H.

    1980-05-01

    Results of a radiological survey performed at the Spook site in Converse County, Wyoming, in June 1976, are presented. The mill at this site was located a short distance from the open-pit mine where the ore was obtained and where part of the tailings was dumped into the mine. Several piles of overburden or low-grade ore in the vicinity were included in the measurements of above-ground gamma exposure rate. The average exposure rate over these piles varied from 14 μR/hr, the average background exposure rate for the area, to 140 μR/hr. The average exposure rate for the tailings and former mill area was 220 μR/hr. Movement of tailings particles down dry washes was evident. The calculated concentration of 226 Ra in ten holes as a function of depth is presented graphically

  15. Similarity of Symbol Frequency Distributions with Heavy Tails

    Directory of Open Access Journals (Sweden)

    Martin Gerlach

    2016-04-01

    Full Text Available Quantifying the similarity between symbolic sequences is a traditional problem in information theory which requires comparing the frequencies of symbols in different sequences. In numerous modern applications, ranging from DNA over music to texts, the distribution of symbol frequencies is characterized by heavy-tailed distributions (e.g., Zipf’s law. The large number of low-frequency symbols in these distributions poses major difficulties to the estimation of the similarity between sequences; e.g., they hinder an accurate finite-size estimation of entropies. Here, we show analytically how the systematic (bias and statistical (fluctuations errors in these estimations depend on the sample size N and on the exponent γ of the heavy-tailed distribution. Our results are valid for the Shannon entropy (α=1, its corresponding similarity measures (e.g., the Jensen-Shanon divergence, and also for measures based on the generalized entropy of order α. For small α’s, including α=1, the errors decay slower than the 1/N decay observed in short-tailed distributions. For α larger than a critical value α^{*}=1+1/γ≤2, the 1/N decay is recovered. We show the practical significance of our results by quantifying the evolution of the English language over the last two centuries using a complete α spectrum of measures. We find that frequent words change more slowly than less frequent words and that α=2 provides the most robust measure to quantify language change.

  16. TIDAL TAILS OF MINOR MERGERS: STAR FORMATION EFFICIENCY IN THE WESTERN TAIL OF NGC 2782

    Energy Technology Data Exchange (ETDEWEB)

    Knierman, Karen; Scowen, Paul; Jansen, Rolf A. [School of Earth and Space Exploration, Arizona State University, 550 East Tyler Mall, Room PSF-686 (P.O. Box 871404), Tempe, AZ 85287-1404 (United States); Knezek, Patricia M. [WIYN Consortium, Inc., 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Wehner, Elizabeth, E-mail: karen.knierman@asu.edu, E-mail: paul.scowen@asu.edu, E-mail: rolf.jansen@asu.edu, E-mail: pknezek@noao.edu, E-mail: ewehner@haverford.edu [Department of Astronomy, Haverford College, Haverford, PA 19041 (United States)

    2012-04-10

    While major mergers and their tidal debris are well studied, they are less common than minor mergers (mass ratios {approx}< 0.3). The peculiar spiral NGC 2782 is the result of a merger between two disk galaxies with a mass ratio of {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 to occur in that tidal tail. However, deep H{alpha} narrowband images show evidence of recent star formation in the western tail. Across the entire western tail, we find the global star formation rate per unit area ({Sigma}{sub SFR}) to be several orders of magnitude less than expected from the total gas density. Together with extended FUV+NUV emission from Galaxy Evolution Explorer along the tail, this indicates a low global star formation efficiency in the tidal tail producing lower mass star clusters. The H II region that we observed has a local (few-kiloparsec scale) {Sigma}{sub SFR} from H{alpha} that is less than that expected from the total gas density, which is consistent with other observations of tidal debris. The star formation efficiency of this H II region inferred from the total gas density is low, but normal when inferred from the molecular gas density. These results suggest the presence of a very small, locally dense region in the western tail of NGC 2782 or of a low-metallicity and/or low-pressure star-forming region.

  17. Thermal stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Williams, J.M.; Cokal, E.J.

    1981-01-01

    The sintering of tailings at high temperatures (1200 0 C) has shown promise as a conditioning approach that greatly reduces the 222 Rn emanation of uranium mill tailings. The structure of thermally stabilized tailings has been appreciably altered producing a material that will have minimal management requirements and will be applicable to on-site processing and disposal. The mineralogy of untreated tailings is presented to define the structure of the original materials. Quartz predominates in most tailings samples; however, appreciable quantities of gypsum, clay, illite, or albites are found in some tailings. Samples from the Durango and Shiprock sites have plagioclase-type aluminosilicates and non-aluminum silicates as major components. The iron-rich vanadium tailings from the Salt Lake City site contain appreciable quantities of α-hematite and chloroapatite. The reduction in radon emanation power and changes in mineralogy as a function of sintering temperature are presented

  18. Which is the most preventive measure against tail damage in finisher pigs: tail docking, straw provision or lowered stocking density?

    DEFF Research Database (Denmark)

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

    2018-01-01

    One challenge of intensive pig production is tail damage caused by tail biting, and farmers often decrease the prevalence of tail damage through tail docking. However, tail docking is not an optimal preventive measure against tail damage and thus, it would be preferable to replace it. The aim of ...

  19. Description of Leishmania (Leishmania forattinii sp. n., a new parasite infecting opossums and rodents in Brazil

    Directory of Open Access Journals (Sweden)

    Elizaide L. A. Yoshida

    1993-09-01

    Full Text Available A new parasite species of Leishmania is described, L. (Leishmania forattinii sp. n., which was isolated from a pooled triturate of liver and spleen of a opossum (Didelphis marsupialis aurita and from skin samples from a rodent (Proechmys iheringi denigratus, captured in primary forest on the Atlantic Cost of Brazil. Our results on the basis of biological and molecular criteria indicate that this taxonomically distinct parasite ias a new species of the L. mexicana complex, but closely related to L. (L. aristidesi Laison & shaw, 1979, as revelated by phenetic and phylogenetic numerical analyses of the enzyme data. L. forattinii was clearly distinguishable from other Leishmania species of the genus usisng enzyme electrophoresis, monoclonal antibodies, molecular karyotypes, analysis of restriction enzyme digestion patterns of kinetoplast DNA (kDNA, as well as the use of kDNA hybridization procedures.

  20. Environmental Assessment of remedial action at the Ambrosia Lake uranium mill tailings site, Ambrosia Lake, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    1987-06-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the Ambrosia Lake uranium mill tailings site located near Ambrosia Lake, New Mexico. The designated site covers 196 acres and contains 111 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for th remedial action (40 CFR Part 192). Remedial action must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion protection measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at an undeveloped location. The no action alternative is also assessed in this document.

  1. Environmental Assessment of remedial action at the Ambrosia Lake uranium mill tailings site, Ambrosia Lake, New Mexico

    International Nuclear Information System (INIS)

    1987-06-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the Ambrosia Lake uranium mill tailings site located near Ambrosia Lake, New Mexico. The designated site covers 196 acres and contains 111 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for th remedial action (40 CFR Part 192). Remedial action must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion protection measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at an undeveloped location. The no action alternative is also assessed in this document

  2. Dexamethasone treatment induces susceptibility of outbred Webster mice to experimental infection with Besnoitia darlingi isolated from opossums (Didelphis virginiana).

    Science.gov (United States)

    Elsheikha, Hany M; Rosenthal, Benjamin M; Mansfield, Linda S

    2005-04-01

    The Sarcocystidae comprise a diverse, monophyletic apicomplexan parasite family, most of whose members form intracellular cysts in their intermediate hosts. The extent of pathology associated with such cyst formation can range widely. We currently lack experimental animal models for many of these infections. Here we explored dexamethasone treatment as a means to render outbred mice susceptible to Besnoitia darlingi infection and demonstrated that this approach allows viable parasites to be subsequently isolated from these mice and maintained in tissue culture. Besnoitia bradyzoites recovered from crushed cysts derived from naturally infected opossums (Didelphis virginiana) replicated and reproduced the development of besnoitiosis in mice treated with dexamethasone (0.5 mg/ml drinking water) daily for 12 days post infection (DPI). Isolates recovered from the peritoneal exudates of these mice were viable and were maintained in long-term tissue cultures. In contrast, control mice given saline without dexamethasone and challenged with similar bradyzoites remained clinically normal for up to 70 DPI. An additional group of mice challenged with the same inoculum of bradyzoites and given dexamethasone at the same concentration and treated with sulfadiazine (1 mg/ml drinking water) daily for 12 DPI also remained normal for up to 70 DPI. Severe disease developed more rapidly in dexamethasone-treated mice inoculated with culture-derived B. darlingi tachyzoites than in those inoculated with cyst-derived bradyzoites. B. darlingi tachyzoite-infected, untreated control mice developed signs of illness at 18 DPI. In contrast, mice treated with sulfadiazine showed no clinical signs up to 50 DPI. Although dexamethasone treatment was required to establish B. darlingi infection in outbred mice inoculated with opossum-derived B. darlingi bradyzoites, no such treatment was required for mice inoculated with culture-derived B. darlingi tachyzoites. Finally, sulfadiazine was highly

  3. Peculiarities of the propagation of multidimensional extremely short optical pulses in germanene

    Energy Technology Data Exchange (ETDEWEB)

    Zhukov, Alexander V., E-mail: alex_zhukov@sutd.edu.sg [Singapore University of Technology and Design, 8 Somapah Road, 487372 Singapore (Singapore); Bouffanais, Roland [Singapore University of Technology and Design, 8 Somapah Road, 487372 Singapore (Singapore); Konobeeva, Natalia N. [Volgograd State University, 400062 Volgograd (Russian Federation); Belonenko, Mikhail B. [Laboratory of Nanotechnology, Volgograd Institute of Business, 400048 Volgograd (Russian Federation); Volgograd State University, 400062 Volgograd (Russian Federation)

    2016-09-07

    Highlights: • Established dynamics of ultra-short pulses in germanene. • Studied balance between dispersive and nonlinear effects in germanene. • Spin–orbit interaction effect onto pulse propagation. - Abstract: In this Letter, we study the propagation characteristics of both two-dimensional and three-dimensional extremely short optical pulses in germanene. A distinguishing feature of germanene—in comparison with other graphene-like structures—is the presence of a significant spin–orbit interaction. The account of this interaction has a significant impact on the evolution of extremely short pulses in such systems. Specifically, extremely short optical pulses, consisting of two electric field oscillations, cause the appearance of a tail associated with the excitation of nonlinear waves. Due to the large spin–orbit interaction in germanene, this tail behind the main pulse is much smaller in germanene-based samples as compared to graphene-based ones, thereby making germanene a preferred material for the stable propagation of pulses along the sample.

  4. Environmental assessment of remedial action at the Tuba City uranium mill tailings site, Tuba City, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    None

    1986-11-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the Tuba City uranium mill tailings site located approximately six miles east of Tuba City, Arizona. The site covers 105 acres and contains 25 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR Part 192). Remedial actions must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion control measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at a more remote location. The no action alternative is also assessed in this document.

  5. Environmental assessment of remedial action at the Tuba City uranium mill tailings site, Tuba City, Arizona

    International Nuclear Information System (INIS)

    1986-11-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the Tuba City uranium mill tailings site located approximately six miles east of Tuba City, Arizona. The site covers 105 acres and contains 25 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR Part 192). Remedial actions must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion control measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at a more remote location. The no action alternative is also assessed in this document

  6. Uranium mill tailings and radon

    International Nuclear Information System (INIS)

    Hanchey, L.A.

    1981-01-01

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100

  7. Uranium mill tailings and radon

    Energy Technology Data Exchange (ETDEWEB)

    Hanchey, L A

    1981-04-01

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the United States may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

  8. Uranium mill tailings and radon

    Energy Technology Data Exchange (ETDEWEB)

    Hanchey, L A

    1981-01-01

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

  9. Value-at-risk estimations of energy commodities via long-memory, asymmetry and fat-tailed GARCH models

    International Nuclear Information System (INIS)

    Aloui, Chaker; Mabrouk, Samir

    2010-01-01

    In this paper, we evaluate the value-at-risk (VaR) and the expected shortfalls for some major crude oil and gas commodities for both short and long trading positions. Classical VaR estimations as well as RiskMetrics and other extensions to cases considering for long-range memory, asymmetry and fat-tail in energy markets volatility were conducted. We computed the VaR for three ARCH/GARCH-type models including FIGARCH, FIAPARCH and HYGARCH. These models were estimated in the presence of three alternative innovation's distributions: normal, Student and skewed Student. Our results show that considering for long-range memory, fat-tails and asymmetry performs better in predicting a one-day-ahead VaR for both short and long trading positions. Moreover, the FIAPARCH model outperforms the other models in the VaR's prediction. These results present several potential implications for energy markets risk quantifications and hedging strategies. (author)

  10. Estimation of Jump Tails

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Todorov, Victor

    We propose a new and flexible non-parametric framework for estimating the jump tails of Itô semimartingale processes. The approach is based on a relatively simple-to-implement set of estimating equations associated with the compensator for the jump measure, or its "intensity", that only utilizes...... the weak assumption of regular variation in the jump tails, along with in-fill asymptotic arguments for uniquely identifying the "large" jumps from the data. The estimation allows for very general dynamic dependencies in the jump tails, and does not restrict the continuous part of the process...... and the temporal variation in the stochastic volatility. On implementing the new estimation procedure with actual high-frequency data for the S&P 500 aggregate market portfolio, we find strong evidence for richer and more complex dynamic dependencies in the jump tails than hitherto entertained in the literature....

  11. Average configuration of the geomagnetic tail

    International Nuclear Information System (INIS)

    Fairfield, D.H.

    1979-01-01

    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-min 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 (B-bar/sub z/=3.γ) than near midnight (B-bar/sub z/=1.8γ). 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 α=-0.9 Y/sub SM/-2.7, where Y/sub SM/ is in earth radii and α is in degrees. After removing these effects, the B/sub 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 0.5γ greater than that during a 'toward' sector, a result that is true in both tail lobes and is independent of location across the tail. This effect means the average field reversal between northern and southern lobes of the tail is more often 178 0 rather than the 180 0 that is generally supposed

  12. Myxofibrosarcoma: prevalence and diagnostic value of the ''tail sign'' on magnetic resonance imaging

    International Nuclear Information System (INIS)

    Lefkowitz, Robert A.; Landa, Jonathan; Hwang, Sinchun; Panicek, David M.; Zabor, Emily C.; Moskowitz, Chaya S.; Agaram, Narasimhan P.

    2013-01-01

    Myxofibrosarcoma frequently shows curvilinear extensions of high T2 signal that also enhance on magnetic resonance imaging; these ''tails'' represent fascial extension of tumor at histopathological examination. This study was performed to determine whether the tail sign is helpful in distinguishing myxofibrosarcoma from other myxoid-containing neoplasms. The study group consisted of 44 patients with pathologically proven myxofibrosarcoma; the control group consisted of 52 patients with a variety of other myxoid-predominant tumors. Three musculoskeletal radiologists independently evaluated T2-weighted (and/or short-tau inversion recovery) and post-contrast MR images for the presence of one or more enhancing, high-signal intensity, curvilinear projections from the primary mass. Sensitivity and specificity for the diagnosis of myxofibrosarcoma were calculated for each reader. Interobserver variability was assessed with kappa statistic and percentage agreement. A tail sign was deemed present in 28, 30, and 34 cases of myxofibrosarcoma and in 11, 9, and 5 of the controls for the three readers respectively, yielding a sensitivity of 64-77 % and a specificity of 79-90 %. The interobserver agreement was moderate-to-substantial (kappa = 0.626). The tail sign at MRI is a moderately specific and sensitive sign for the diagnosis of myxofibrosarcoma relative to other myxoid-containing tumors. (orig.)

  13. Ectopic expression of Ptf1a induces spinal defects, urogenital defects, and anorectal malformations in Danforth's short tail mice.

    Directory of Open Access Journals (Sweden)

    Kei Semba

    Full Text Available Danforth's short tail (Sd is a semidominant mutation on mouse chromosome 2, characterized by spinal defects, urogenital defects, and anorectal malformations. However, the gene responsible for the Sd phenotype was unknown. In this study, we identified the molecular basis of the Sd mutation. By positional cloning, we identified the insertion of an early transposon in the Sd candidate locus approximately 12-kb upstream of Ptf1a. We found that insertion of the transposon caused overexpression of three neighboring genes, Gm13344, Gm13336, and Ptf1a, in Sd mutant embryos and that the Sd phenotype was not caused by disruption of an as-yet-unknown gene in the candidate locus. Using multiple knockout and knock-in mouse models, we demonstrated that misexpression of Ptf1a, but not of Gm13344 or Gm13336, in the notochord, hindgut, cloaca, and mesonephros was sufficient to replicate the Sd phenotype. The ectopic expression of Ptf1a in the caudal embryo resulted in attenuated expression of Cdx2 and its downstream target genes T, Wnt3a, and Cyp26a1; we conclude that this is the molecular basis of the Sd phenotype. Analysis of Sd mutant mice will provide insight into the development of the spinal column, anus, and kidney.

  14. Segregation and differential settling in flocculated tailings

    Energy Technology Data Exchange (ETDEWEB)

    Farinato, R.S.; Mahmoudkhani, A.; Fenderson, T.; Watson, P. [Kemira, Atlanta, GA (United States)

    2010-07-01

    Untreated oil sands tailings have a high solids content, have poor dewaterability, and contain no aggregates. This PowerPoint presentation investigated segregation and differential settling in flocculated tailings. Tailings were treated with gypsum and various polymers. Cylinder settling, dynamic rheometry, particle size analysis, and microscopy techniques were used to characterize the composite tailings. The particles sizes of the samples were evaluated in relation to shear rate, bed depth, and treatment. The study showed that the gypsum-treated tailings had small aggregates, size stratification, a high solids content, and poor dewaterability. The polymer N-treated tailings had the lowest solids content, good dewaterability, and weak aggregates. The polymer A-treated tailings had a low solids content, very good dewaterability, and strong aggregates. The addition of a coagulant to the polymer-A treated tailings provided weaker aggregates and a higher solids content. tabs., figs.

  15. Ecotoxicity of Mine Tailings: Unrehabilitated Versus Rehabilitated.

    Science.gov (United States)

    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 tailings. In addition, significantly lower (p tailings compared to the unrehabilitated. Further, significantly lower (p 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.

  16. ESTIMATION OF FILTRATION CAPACITY OF POSTFLOTATION TAILINGS EMBEDDED IN DAMS OF TAILINGS DEPOSITION SITES

    Directory of Open Access Journals (Sweden)

    Wojciech Tschuschke

    2015-10-01

    Full Text Available Construction of very big mine tailings deposition sites, such as postflotation tailings ponds, is a complicated engineering task, in which several technical and environmental problems need to be solved. Designing, construction and operation of such an object applying the monitoring method consists in the verification of design assumptions based on continuous observations. One of the primary tasks of monitoring while the deposition site is being filled with tailings is to control quality of the formed dam embankments, as the structural element of the object responsible for its stability. In order to use material selected from deposited tailings in the construction of dams it is necessary to define grain size and compaction criteria, which directly affect load bearing capacity and deformation of the structure. For this reason main control tests include the analyses of grain size distribution and physical properties of the material embedded in the dams. These data may also be used to estimate filtration capacity of the embankment. A lack of drainage, causing accumulation of water within the embankment, may potentially deteriorate stability conditions. This paper presents the use of empirical formulas, i.e. formulas typically applied to natural soils, to assess permeability coefficient of tailings. A simple empirical formula was also proposed for the estimation of permeability coefficient of tailings based on grain size and compaction parameters determined in routine quality tests of constructed dam embankments.

  17. Sub-aerial tailings deposition

    International Nuclear Information System (INIS)

    Knight, R.B.; Haile, J.P.

    1984-01-01

    The sub-aerial technique involves the systematic deposition of tailings in thin layers and allowing each layer to settle, drain and partially air dry prior to covering with a further layer. Underdrainage produces densities in excess of those achieved by sub-aqueous deposition and any air-drying serves to preconsolidate each layer with a resulting further increase in density. The low permeability of the tailings surface resulting from this deposition technique results in high runoff coefficients and, by decanting the runoff component of direct precipitation, a net evaporation condition can be achieved even in high rainfall areas. An underdrainage system prevents the build-up of excess pore-pressures within the tailings mass and at decommissioning the tailings are fully consolidated and drained thereby eliminating the possibility of any long term seepage. This paper presents a general description of these design concepts, and details of two projects where the concepts have been applied

  18. Arrangement of the myenteric plexus throughout the gastrointestinal tract of the opossum.

    Science.gov (United States)

    Christensen, J; Rick, G A; Robison, B A; Stiles, M J; Wix, M A

    1983-10-01

    Silver impregnation of the myenteric plexus of the opossum gut was used to find differences among various regions. In the esophagus, the plexus was sparse and ganglia were spaced irregularly, many being parafascicular. Ganglia were sparse in the striated-muscle region, but more frequent in the smooth-muscle region. In the stomach, uniformly spaced ganglia were large and intrafascicular; ganglia were larger in the distal stomach than in the proximal stomach. The proximal stomach contained thick fascicles, called shunt fascicles, radiating from the lesser to the greater curvatures and bypassing ganglia. A thick nerve bundle encircled the pylorus. In the small intestine, the regularly spaced ganglia were large and intrafascicular. In the cecum, they were small and intrafascicular. In the colon, they were large and intrafascicular. Shunt fascicles, like those of the proximal stomach, extended from the rectum into the distal colon. In the rectum, the plexus was sparse, and ganglia were small and distributed irregularly. Many ganglia were parafascicular. Unique knots of tangled fascicles were frequent in the rectum; these were called labyrinthine nodes. The least densely innervated regions of the gut are the lower esophageal sphincter and the rectum. Major differences in the anatomy of the plexus characterize the different regions of the gut.

  19. Markov Tail Chains

    OpenAIRE

    janssen, Anja; Segers, Johan

    2013-01-01

    The extremes of a univariate Markov chain with regularly varying stationary marginal distribution and asymptotically linear behavior are known to exhibit a multiplicative random walk structure called the tail chain. In this paper we extend this fact to Markov chains with multivariate regularly varying marginal distributions in Rd. We analyze both the forward and the backward tail process and show that they mutually determine each other through a kind of adjoint relation. In ...

  20. Diagnostic analysis of electrodialysis in mine tailing materials

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Ribeiro, Alexandra B.; Mateus, Eduardo

    2007-01-01

    Removal of heavy metals from mine tailings and soil contaminated by copper mining activities was studied under batch electrodialytic conditions. Two types of mine tailings were treated: (i) freshly produced tailings coming directly from the flotation process, and (ii) tailings deposited...... in a tailings pond, for approximately 20 years. The main contaminant was copper-found in concentration around 800-1800 ppm. The fractionation of copper and other characteristics of the tailings differ for the two tailings, indicating natural oxidation reactions in the old deposited ones. Electrodialytical...

  1. Tales of island tails

    NARCIS (Netherlands)

    Groot, de Alma V.; Oost, Albert P.; Veeneklaas, Roos M.; Lammerts, Evert Jan; Duin, van Willem E.; Wesenbeeck, van Bregje K.

    2016-01-01

    The Frisian islands (Southern North Sea) have extensive island tails, i.e. the entire downdrift side of an island consisting of salt marshes, dunes, beaches and beach plains, and green beaches. Currently, large parts of these tails are ageing and losing dynamics, partly due to human influence.

  2. Environmental Assessment for Wing Infrastructure Development Outlook (WINDO) Plan Shaw Air Force Base, South Carolina

    Science.gov (United States)

    2004-10-01

    officially established on August 30, 1941 and was named after 1st Lt. Ervin D. Shaw, a Sumter County resident who was killed in action during World War I...Examples of the animal species likely to occur within this community include the cottontail, mockingbird , American robin, and crow. At the Poinsett...include the white-tailed deer, red fox, raccoon, opossum, striped skunk, cottontail, meadowlark, mockingbird , American kestrel, fence lizard, and

  3. Characterization of Trypanosoma cruzi Strains Isolated from Chronic Chagasic Patients, Triatomines and Opossums Naturally Infected from the State of Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Cloé Duarte Fernandes

    1997-05-01

    Full Text Available Thirty-five Trypanosoma cruzi strains were isolated from chronic chagasic patients, triatomines and opossums from different municipalities of the State of Rio Grande do Sul. Parasites were characterized by means of mice infectivity, enzyme electrophoresis and randomly amplified polymorphic DNA (RAPD analysis. Twenty-nine strains were isolated from chagasic patients, 4 from triatomines (2 from Triatoma infestans and 2 from Panstrongylus megistus and 2 from opossums Didelphis albiventris. Thirty-three T. cruzi strains were of low and 2 strains of high virulence in mice. Both virulent strains were isolated from P. megistus. Isoenzyme analysis of the strains showed 3 different zymodemes. Eleven strains isolated from chagasic patients and 2 from D. albiventris were Z2. Eighteen strains from patients and 2 from T. infestans were ZB and 2 T. cruzi strains isolated from P. megistus were Z1. RAPD profiles obtained with 4 random primers showed a high genetic heterogeneity of the T. cruzi strains. Zymodeme 2 and ZB strains were the more polymorphic. A band sharing analysis of the RAPD profiles of Z2 and ZB strains using 3 primers, showed a very low percentage of shared bands, 20% among 13 ZB strains and 14% among 13 Z2 strains. According to the isoenzyme results, 3 T. cruzi populations were present in State of Rio Grande do Sul. Zymodeme 2 and ZB strains were found infecting man (domiciliar transmission cycle whereas Z1 strains were found infecting the sylvatic vector P. megistus

  4. Meeting the challenge - solutions for managing oil sands tailings: report of the fine tailings fundamentals consortium 1989-1995

    International Nuclear Information System (INIS)

    1996-01-01

    The development and demonstration of effective alternatives for the management of fine tailings in the oil sands industry were discussed in a report describing the work of the Fine Tailings Fundamentals Consortium during the period from 1989 to 1995. The final report of the Consortium is a four-volume publication entitled 'Advances in Oil Sands Tailings Research' which is the state-of-the-art reference to key issues in the reclamation of fine tailings. Government regulations now make it the responsibility of industry to integrate the fine tailings into reclaimed landscapes, so that the final landscape is equal in productive capability to the pre-disturbed state. Impressive progress has been made in understanding the formation of fine tailings and in characterizing their properties, much of it through the work of this Consortium. Fundamental research on the clay particles within fine tailings provides a better understanding of how to manage them. Although there is no 'magic bullet', research has demonstrated that an integrated approach incorporating fine tailings with a variety of elements, uplands, lakes and wetlands, offer the best hope for an environmentally sound solution. figs

  5. The Tail of BPM

    Science.gov (United States)

    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.

  6. Effects of Tail Clipping on Larval Performance and Tail Regeneration Rates in the Near Eastern Fire Salamander, Salamandra infraimmaculata.

    Directory of Open Access Journals (Sweden)

    Ori Segev

    Full Text Available Tail-tip clipping is a common technique for collecting tissue samples from amphibian larvae and adults. Surprisingly, studies of this invasive sampling procedure or of natural tail clipping--i.e., bites inflicted by predators including conspecifics--on the performance and fitness of aquatic larval stages of urodeles are scarce. We conducted two studies in which we assessed the effects of posterior tail clipping (~30 percent of tail on Near Eastern fire salamander (Salamandra infraimmaculata larvae. In a laboratory study, we checked regeneration rates of posterior tail-tip clipping at different ages. Regeneration rates were hump-shaped, peaking at the age of ~30 days and then decreasing. This variation in tail regeneration rates suggests tradeoffs in resource allocation between regeneration and somatic growth during early and advanced development. In an outdoor artificial pond experiment, under constant larval densities, we assessed how tail clipping of newborn larvae affects survival to, time to, and size at metamorphosis. Repeated measures ANOVA on mean larval survival per pond revealed no effect of tail clipping. Tail clipping had correspondingly no effect on larval growth and development expressed in size (mass and snout-vent length at, and time to, metamorphosis. We conclude that despite the given variation in tail regeneration rates throughout larval ontogeny, clipping of 30% percent of the posterior tail area seems to have no adverse effects on larval fitness and survival. We suggest that future use of this imperative tool for the study of amphibian should take into account larval developmental stage during the time of application and not just the relative size of the clipped tail sample.

  7. Characterization and dewatering of flotation technological tailings

    Directory of Open Access Journals (Sweden)

    Grigorova I.

    2014-01-01

    Full Text Available The treatment of flotation tailings is today a subject of interest in mineral processing because of the potential of wasted materials as an actual mineral resource and because of environmental reasons. Decantation ponds are found at almost every mine in the world. They are large earth fill dams containing the residue of the milling process to extract metals from mined ores. Traditional wet tailings disposal has been problematic due to the risk of ground water contamination and the difficulty in rehabilitating storage sites. Tailings dams are at risk of failure due to leakage, instability, liquefaction, and poor design. In the last few years the use of paste technology in the disposal of mine tailings is increasingly studied as an option to conventional tailings dams. The Lucky Invest Concentrator is located in the Eastern Rhodopes Mountain of Bulgaria. Since 1959 lead-zinc ores are dressed. Finally, during the flotation cycle lead and zinc concentrates are produced. The final technological processing waste precipitates in tailing pond. Research and development program has started to established opportunities to obtain dry deposit of the ore processing residue and analyses the feature of new tailing disposal method. The tailings particle size distributions and chemical compositions were determined. The data from laboratory and pilot scale tests clearly illustrate that there are the possibilities to obtaine lead-zinc dewatered tailings. The experimental results show that new cyclone modifications have a potential in dewatering technology of flotation tailings. It appears that dewatering cyclones can be an approach on new tailings pond elimination technology.

  8. Uranium mill tailings stabilization

    International Nuclear Information System (INIS)

    Hartley, J.N.; Koehmstedt, P.L.; Esterl, D.J.; Freeman, H.D.

    1980-02-01

    Uranium mill tailings pose a potential radiation health hazard to the public. Therefore, stabilization or disposal of these tailings in a safe and environmentally sound way is needed to minimize radon exhalation and other environmental hazards. One of the most promising concepts for stabilizing U tailings is the use of asphalt emulsion to contain radon and other hazardous materials within uranium tailings. This approach is being investigated at the Pacific Northwest Laboratory. Results of these studies indicate that a radon flux reduction of greater than 99% can be obtained using either a poured-on/sprayed-on seal (3.0 to 7.0 mm thick) or an admixture seal (2.5 to 12.7 cm thick) containing about 18 wt % residual asphalt. A field test was carried out in June 1979 at the Grand Junction tailings pile in order to demonstrate the sealing process. A reduction in radon flux ranging from 4.5 to greater than 99% (76% average) was achieved using a 15.2-cm (6-in.) admix seal with a sprayed-on top coat. A hydrostatic stabilizer was used to apply the admix. Following compaction, a spray coat seal was applied over the admix as the final step in construction of a radon seal. Overburden was applied to provide a protective soil layer over the seal. Included in part of the overburden was a herbicide to prevent root penetration

  9. Liquefaction of uranium tailings

    International Nuclear Information System (INIS)

    1992-02-01

    Numerical methods for assessing the liquefaction potential of soils are reviewed with a view to their application to uranium tailings. The method can be divided into two categories: total stress analysis, where changes in pore pressure are not considered in the soil model, and effective stress analysis, where changes in pore pressure are included in the soil model. Effective stress analysis is more realistic, but few computer programs exist for such analysis in two or three dimensions. A simple linearized, two-dimensional, finite element effective stress analysis which incorporates volumetric compaction due to shear motion is described and implemented. The new program is applied to the assessment of liquefaction potential of tailings in the Quirke Mine tailings area near Elliot Lake, Ontario. The results are compared with those of a total stress analysis. Both analyses indicate liquefaction would occur if a magnitude 6.0 earthquake were to occur near the area. However, the extent of liquefaction predicted by the effective stress analysis is much less than that predicted by the total stress analysis. The results of both methods are sensitive to assumed material properties and to the method used to determine the cyclic shear strength of the tailings. Further analysis, incorporating more in situ and/or laboratory data, is recommended before conclusions can be made concerning the dynamic stability of these tailings

  10. The impacts of the Samarco mine tailing spill on the Rio Doce estuary, Eastern Brazil.

    Science.gov (United States)

    Gomes, Luiz Eduardo de Oliveira; Correa, Lucas Barreto; Sá, Fabian; Neto, Renato Rodrigues; Bernardino, Angelo Fraga

    2017-07-15

    Over 50 million cubic meters of mining tailings were released in the Rio Doce basin after the collapse of the Fundão dam (Samarco) in November 2015. Predicting significant impacts on the Rio Doce estuary, we sampled sediments to investigate short-term impacts on the benthic assemblages and trace metal accumulation on estuarine sediments. With the arrival of the tailing plumes in the estuary, we detected a predominance of clay particles and increased trace metal concentrations of up to 5 times in some areas. The rapid sedimentation after the impact also impacted estuarine macrofaunal assemblages through loss surface-dwelling taxa. As expected, the impacts on benthic assemblages observed up to 3days after the arrival of tailings were not clearly associated with trace metal concentrations, but long-term effects need to be studied. We recommend that the high spatial variability within the estuary be considered in future impact assessment studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Mouse Y-Encoded Transcription Factor Zfy2 Is Essential for Sperm Head Remodelling and Sperm Tail Development

    NARCIS (Netherlands)

    Vernet, Nadege; Mahadevaiah, Shantha K.; Decarpentrie, Fanny; Longepied, Guy; de Rooij, Dirk G.; Burgoyne, Paul S.; Mitchell, Michael J.

    2016-01-01

    A previous study indicated that genetic information encoded on the mouse Y chromosome short arm (Yp) is required for efficient completion of the second meiotic division (that generates haploid round spermatids), restructuring of the sperm head, and development of the sperm tail. Using mouse models

  12. Predicting radon flux from uranium mill tailings

    International Nuclear Information System (INIS)

    Freeman, H.D.; Hartley, J.N.

    1983-11-01

    Pacific Northwest Laboratory (PNL), under contract to the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) office, is developing technology for the design of radon barriers for uranium mill tailings piles. To properly design a radon cover for a particular tailings pile, the radon flux emanating from the bare tailings must be known. The tailings characteristics required to calculate the radon flux include radium-226 content, emanating power, bulk density, and radon diffusivity. This paper presents theoretical and practical aspects of estimating the radon flux from an uranium tailings pile. Results of field measurements to verify the calculation methodology are also discussed. 24 references, 4 figures, 4 tables

  13. Environmental assessment of remedial action at the Gunnison Uranium Mill Tailings Site, Gunnison, Colorado. [UMTRA Project

    Energy Technology Data Exchange (ETDEWEB)

    Bachrach, A.; Hoopes, J.; Morycz, D. (Jacobs Engineering Group, Inc., Pasadena, CA (USA)); Bone, M.; Cox, S.; Jones, D.; Lechel, D.; Meyer, C.; Nelson, M.; Peel, R.; Portillo, R.; Rogers, L.; Taber, B.; Zelle, P. (Weston (Roy F.), Inc., Washington, DC (USA)); Rice, G. (Sergent, Hauskins and Beckwith (USA))

    1984-12-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the Gunnison uranium of mill tailings site located 0.5 miles south of Gunnison, Colorado. The site covers 56 acres and contains 35 acres of tailings, 2 of the original mill buildings and a water tower. The Uranium Mill Tailings Radiation Control of Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated (vicinity) properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR 192). Remedial actions must be performed in accordance with these standards and with the occurrence of the Nuclear Regulatory Commission. Four alternatives have been addressed in this document. The first alternative is to consolidate the tailings and associated contaminated soils into a recontoured pile on the southern portion of the existing site. A radon barrier of silty clay would be constructed over the pile and various erosion control measures would be taken to assure the long-term integrity of the pile. Two other alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives generally involve greater short-term impacts and are more costly but would result in the tailings being stabilized in a location farther from the city of Gunnison. The no action alternative is also assessed.

  14. Numerical modelling for stability of tailings dams

    OpenAIRE

    Auchar, Muhammad; Mattsson, Hans; Knutsson, Sven

    2013-01-01

    A tailings dam is a large embankment structure that is constructed to store the waste from the mining industry. Stability problems may occur in a tailings dam due to factors such as quick rate of raising, internal erosion and liquefaction. The failure of a tailings dam may cause loss of human life and environmental degradation. Tailings Dams must not only be stable during the time the tailings storage facility is in operation, but also long time after the mine is closed. In Sweden, the licens...

  15. Height distribution tails in the Kardar-Parisi-Zhang equation with Brownian initial conditions

    Science.gov (United States)

    Meerson, Baruch; Schmidt, Johannes

    2017-10-01

    For stationary interface growth, governed by the Kardar-Parisi-Zhang (KPZ) equation in 1 + 1 dimensions, typical fluctuations of the interface height at long times are described by the Baik-Rains distribution. Recently Chhita et al (2016 arXiv:1611.06690) used the totally asymmetric simple exclusion process (TASEP) to study the height fluctuations in systems of the KPZ universality class for Brownian interfaces with arbitrary diffusion constant. They showed that there is a one-parameter family of long-time distributions, parameterized by the diffusion constant of the initial random height profile. They also computed these distributions numerically by using Monte Carlo (MC) simulations. Here we address this problem analytically and focus on the distribution tails at short times. We determine the (stretched exponential) tails of the height distribution by applying the optimal fluctuation method (OFM) to the KPZ equation. We argue that, by analogy with other initial conditions, the ‘slow’ tail holds at arbitrary times and therefore provides a proper asymptotic to the family of long-time distributions studied in Chhita et al (2016 arXiv:1611.06690). We verify this hypothesis by performing large-scale MC simulations of a TASEP with a parallel-update rule. The ‘fast’ tail, predicted by the OFM, is also expected to hold at arbitrary times, at sufficiently large heights.

  16. Acid production potentials of massive sulfide minerals and lead-zinc mine tailings: a medium-term study.

    Science.gov (United States)

    Çelebi, Emin Ender; Öncel, Mehmet Salim; Kobya, Mehmet

    2018-01-01

    Weathering of sulfide minerals is a principal source of acid generation. To determine acid-forming potentials of sulfide-bearing materials, two basic approaches named static and kinetic tests are available. Static tests are short-term, and easily undertaken within a few days and in a laboratory. In contrast, kinetic tests are long-term procedures and mostly carried out on site. In this study, experiments were conducted over a medium-term period of 2 months, not as short as static tests and also not as long as kinetic tests. As a result, pH and electrical conductivity oscillations as a function of time, acid-forming potentials and elemental contents of synthetically prepared rainwater leachates of massive sulfides and sulfide-bearing lead-zinc tailings from abandoned and currently used deposition areas have been determined. Although the lowest final pH of 2.70 was obtained in massive pyrite leachate, massive chalcopyrite leachate showed the highest titrable acidity of 1.764 g H 2 SO 4 /L. On the other hand, a composite of currently deposited mine tailings showed no acidic characteristic with a final pH of 7.77. The composite abandoned mine tailing leachate had a final pH of 6.70, close to the final pH of massive galena and sphalerite leachates, and produced a slight titrable acidity of 0.130 g H 2 SO 4 /L.

  17. Post-precipitation bias in band-tailed pigeon surveys conducted at mineral sites

    Science.gov (United States)

    Overton, C.T.; Schmitz, R.A.; Casazza, Michael L.

    2005-01-01

    Many animal surveys to estimate populations or index trends include protocol prohibiting counts during rain but fail to address effects of rainfall preceding the count. Prior research on Pacific Coast band-tailed pigeons (Patagioenas fasciata monilis) documented declines in use of mineral sites during rainfall. We hypothesized that prior precipitation was associated with a short-term increase in use of mineral sites following rain. We conducted weekly counts of band-tailed pigeons at 19 Pacific Northwest mineral sites in 2001 and 20 sites in 2002. Results from regression analysis indicated higher counts ???2 days after rain (11.31??5.00% [x????SE]) compared to ???3 days. Individual index counts conducted ???2 days after rain were biased high, resulting in reduced ability to accurately estimate population trends. Models of band-tailed pigeon visitation rates throughout the summer showed increased mineral-site counts during both June and August migration periods, relative to the July breeding period. Our research supported previous studies recommending that mineral-site counts used to index the band-tailed pigeon population be conducted during July. We further recommend conducting counts >3 days after rain to avoid weather-related bias in index estimation. The design of other population sampling strategies that rely on annual counts should consider the influence of aberrant weather not only coincident with but also preceding surveys if weather patterns are thought to influence behavior or detection probability of target species.

  18. Multichannel thickener of flotation tailings

    Energy Technology Data Exchange (ETDEWEB)

    Kondratenko, A F; Shuliko, A N; Zinchenko, A F

    1983-04-01

    A multichannel thickener of flotation tailings developed by Ukrniiugleobogashchenie is described. Tailings with solid content ranging from 40 to 60 g/l are mixed with flocculation reagents (quantity ratio from 60 to 70 g/l) in a turbulent mixer: waste water with tailings fed to the mixer is divided into three streams, flocculation reagents are batched in stages with each water stream. After turbulent mixing, water, tailings and reagent are fed to the settling chamber. Settling chamber (dimensions 2.4 x 1.5 x 1.0 m) is divided into a number of channels by settling surfaces of 0.35 m/sup 2/ each, inclined at an angle of 55 degrees. Distance between the surfaces is 50 mm. The thickener has a total settling surface of 18.7 m/sup 2/. Water with tailings flows upwards, cleaned water is removed by a separating system and settled tailings move downward and accumulate in the compacting chamber (dimensions 1.5 x 1.5 x 0.9 m). From the compacting chamber thickened slurry with solid content from 90 to 150 g/l is removed by a hydraulic system. During performance testing in some plants preparing coal difficult to wash, thickening efficiency amounted to 100%. The results of performance testing are shown in two tables. Factors which influence thickener productivity are evaluated. (In Russian)

  19. Environmental assessment of remedial action at the Shiprock uranium mill tailings site, Shiprock, New Mexico: Volume 1, Text

    Energy Technology Data Exchange (ETDEWEB)

    None

    1984-05-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the shiprock uranium mill tailings site located on the Navajo Indian Reservation, one mile south of Shiprock, New Mexico. The site contains 72 acres of tailings and four of the original mill buildings. The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR 192). Remedial actions must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated soils into a recontoured pile. A seven-foot-thick radon barrier would be constructed over the pile and various erosion control measures would be taken to assure the long-term integrity of the pile. Three other alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives generally involve greater short-term impacts and are more costly but would result in the tailings being stabilized in a more remote location. The no action alternative is also assessed. 99 refs., 40 figs., 58 tabs.

  20. Environmental assessment of remedial action at the Shiprock uranium mill tailings site, Shiprock, New Mexico: Volume 1, Text

    International Nuclear Information System (INIS)

    1984-05-01

    This document assesses and compares the environmental impacts of various alternatives for remedial action at the shiprock uranium mill tailings site located on the Navajo Indian Reservation, one mile south of Shiprock, New Mexico. The site contains 72 acres of tailings and four of the original mill buildings. The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR 192). Remedial actions must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated soils into a recontoured pile. A seven-foot-thick radon barrier would be constructed over the pile and various erosion control measures would be taken to assure the long-term integrity of the pile. Three other alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives generally involve greater short-term impacts and are more costly but would result in the tailings being stabilized in a more remote location. The no action alternative is also assessed. 99 refs., 40 figs., 58 tabs

  1. Habitat associations of small mammals in southern Brazil and use of regurgitated pellets of birds of prey for inventorying a local fauna

    Directory of Open Access Journals (Sweden)

    DR. Scheibler

    Full Text Available We inventoried terrestrial small mammals in an agricultural area in southern Brazil by using trapping and prey consumed by Barn Owls (Tyto alba and White-tailed Kites (Elanus leucurus. Small mammals were trapped in three habitat types: corn fields, uncultivated fields ("capoeiras", and native forest fragments. A total of 1,975 small mammal specimens were trapped, another 2,062 identified from the diet of Barn Owls, and 2,066 from the diet of White-tailed Kites. Both trapping and prey in the predators' diet yielded 18 small mammal species: three marsupials (Didelphis albiventris, Gracilinanus agilis, and Monodelphis dimidiata and 15 rodents (Akodon paranaensis, Bruceppatersonius iheringi, Calomys sp., Cavia aperea, Euryzygomatomys spinosus, Holochilus brasiliensis, Mus musculus, Necromys lasiurus, Nectomys squamipes, Oligoryzomys nigripes, Oryzomys angouya, Oxymycterus sp.1, Oxymycterus sp.2, Rattus norvegicus, and Rattus rattus (Linnaeus, 1758. The greatest richness was found in the uncultivated habitat. We concluded that the three methods studied for inventorying small mammals (prey in the diet of Barn Owls, White-tailed Kites, and trapping were complementary, since together, rather than separately, they produced a better picture of local richness.

  2. The long-term environmental impacts of the Mount Polley mine tailings spill, British Columbia, Canada

    Science.gov (United States)

    Byrne, Patrick; Hudson-Edwards, Karen; Macklin, Mark; Brewer, Paul; Bird, Graham; Williams, Richard

    2015-04-01

    On the 4th August 2014 a tailings impoundment failure at the Mount Polley gold and copper mine in British Columbia, Canada, released approximately 25 million m3 of solid and liquid waste into Hazeltine Creek, Quesnel Lake and Polley Lake. The sheer volume of the tailings released caused Haseltine Creek channel to expand from 2m to over 25m in width and Polley Lake water level to rise by 1.7m. The spill also removed trees in a 900 km2 corridor either side of Hazeltine Creek. Local residents and government officials have expressed serious concerns regarding the potential long-term effects on regional biodiversity, water security and to the livelihoods of First Nation communities. Among impoundment failures, the Mount Polley disaster is unique in that the solid tailings contain an unusual mixture of metal contaminants (arsenic, copper, gold, manganese, nickel, lead, vanadium). As particulate matter is the principal carrier of metal contaminants, the spilled tailings may reside in the regional soils and sediments for 1000s of years serving as a secondary source of pollution. The environmental risk posed by the spilled tailings is compounded by the location of the spill in a mountainous forested catchment, affected by severe winters with prominent spring snow melts that have the potential to remobilise very large quantities of spilled tailings. No data currently exist on the short- to long-term behaviour of these tailings in soils and sediments and the effects of the clean-up operations on their behaviour in this type of river environment. In this study, we adopt a multidisciplinary approach to determine the environmental and geomorphological impacts of the tailings spill. We have two specific objectives. (1) The physicochemical speciation and geochemical stability of spilled tailings will be characterised in surface and hyporheic sediments using bulk chemistry, mineralogical (XRD and SEM) and speciation methods (sequential extractions, electron microprobe analysis, XAS

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

    Science.gov (United States)

    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.

  4. Mineralogy and geochemistry of uranium mill tailings

    International Nuclear Information System (INIS)

    Pagel, M.; Somot, S.

    2002-01-01

    We have investigated three main types of uranium mill tailings: (1) acid mill tailings (Mounana, Gabon), (2) neutralized acid mill tailings (Ecarpiere and Jouac, France) and (3) alkaline mill tailings (Lodeve, France). We have focused especially on radium behaviour which is of major environmental concern in these tailings, but other metals were also studied. It is shown that in type 1 , trapping of 226 Ra by anglesite and barite is dominant whereas in types 2 and 3, 226 Ra is mainly or significantly scavenged by Fe- Mn oxyhydroxides. This study points out the importance of keeping conditions in which these oxyhydroxides will be stable for the long-term. Uranium would be also released during acidification of the tailings. This shows the importance to know more about the behavior of Ra during the crystallization of oxyhydroxides and during tailings diagenesis. Therefore, it is very important to study the sorption of Ra by clay minerals or late authigeneous minerals such as barite. (author)

  5. A guide to the management of tailings facilities

    International Nuclear Information System (INIS)

    Bedard, C.; Ferguson, K.; Gladwin, D.; Lang, D.; Maltby, J.; McCann, M.; Poirier, P.; Schwenger, R.; Vezina, S.; West, S.; Duval, J.; Gardiner, E.; Jansons, K.; Lewis, B.; Matthews, J.; Mchaina, D.; Puro, M.; Siwik, R.; Welch, D.

    1998-01-01

    The 'Guide to the Management of Tailings Facilities' has been developed by the Mining Association of Canada in an effort to provide guidance to its member companies on sound practices for the safe and environmentally responsible management of tailings facilities. The guide is a reference tool to help companies ensure that they are managing their tailings facilities responsibly, integrating environmental and safety considerations in a consistent manner, with continuous improvement in the operation of tailings facilities. The key to managing tailings responsibly is consistent application of engineering capabilities through the full life cycle. The guide provides a basis for the development of customized tailings management systems to address specific needs at individual operations, and deals with environmental impacts, mill tailing characteristics, tailings facility studies and plans, dam and related structure design, and control and monitoring. Aspects relating to tailings facility siting, design, construction, operation, decommissioning and closure are also fully treated. 1 tab., 3 figs

  6. Taming the tailings : dead ducks notwithstanding, extensive research is underway to deal with oilsands tailings in a more efficient manner

    Energy Technology Data Exchange (ETDEWEB)

    Collison, M.

    2008-09-15

    Research is now being conducted to reduce the environmental impacts of oil sands tailing ponds. Alberta's oil sands region contains an estimated 60 km{sup 2} of tailings ponds, which serve as holding basins for recycled water as well as collection sites for materials used in reclamation activities. The ponds contain residual bitumen, production chemicals, and minerals. While some of the water in the ponds can be re-used, mature fine tailings must be contained behind dikes. Every barrel of bitumen produced by the industry results in the creation of 1.5 barrels of mature fine tailings. Natural Resources Canada's CANMET Energy Technology Centre is currently conducting a research program with the University of Alberta to reduce the amounts of tailings produced by the industry. Options for dry stackable tailings are being explored, as well as methods of using the tailings to enhance various oil sands processes. It is hoped that the dry, stackable tailings can be used to help reclaim and rebuild Boreal regions impacted by the oil sands industry. The program is gaining interest due to concerns that leakages from the tailings ponds may pollute aquifers and rivers in a region noted for its water shortages. Research teams are also investigating the use of flocculants to create heavy non-segregated tailings. Researchers are also examining methods of recovering hydrocarbons, titanium, and zircon from the tailings. 3 figs.

  7. Assessing Risks of Mine Tailing Dam Failures

    Science.gov (United States)

    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.

  8. Analysis of Heavy-Tailed Time Series

    DEFF Research Database (Denmark)

    Xie, Xiaolei

    This thesis is about analysis of heavy-tailed time series. We discuss tail properties of real-world equity return series and investigate the possibility that a single tail index is shared by all return series of actively traded equities in a market. Conditions for this hypothesis to be true...... are identified. We study the eigenvalues and eigenvectors of sample covariance and sample auto-covariance matrices of multivariate heavy-tailed time series, and particularly for time series with very high dimensions. Asymptotic approximations of the eigenvalues and eigenvectors of such matrices are found...... and expressed in terms of the parameters of the dependence structure, among others. Furthermore, we study an importance sampling method for estimating rare-event probabilities of multivariate heavy-tailed time series generated by matrix recursion. We show that the proposed algorithm is efficient in the sense...

  9. Monte Carlo-based tail exponent estimator

    Science.gov (United States)

    Barunik, Jozef; Vacha, Lukas

    2010-11-01

    In this paper we propose a new approach to estimation of the tail exponent in financial stock markets. We begin the study with the finite sample behavior of the Hill estimator under α-stable distributions. Using large Monte Carlo simulations, we show that the Hill estimator overestimates the true tail exponent and can hardly be used on samples with small length. Utilizing our results, we introduce a Monte Carlo-based method of estimation for the tail exponent. Our proposed method is not sensitive to the choice of tail size and works well also on small data samples. The new estimator also gives unbiased results with symmetrical confidence intervals. Finally, we demonstrate the power of our estimator on the international world stock market indices. On the two separate periods of 2002-2005 and 2006-2009, we estimate the tail exponent.

  10. Uranium mill tailings remedial action technology

    International Nuclear Information System (INIS)

    Hartley, J.N.; Gee, G.W.

    1984-01-01

    The uranium milling process involves the hydrometallurgical extraction of uranium from ores and the resultant generation of large quantities of waste referred to as tailings. Uranium mill tailings have been identified as requiring remediation because they contain residual radioactive material that is not removed in the milling process. Potential radiation exposure can result from direct contact with the tailings, from radon gas emitted by the tailings, and from radioactive contamination of groundwater. As a result, the technology developed under the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) and the US Nuclear Regulatory Commission (NRC) Uranium Recovery Program have focused on radon control, groundwater contamination and the long-term protection of the containment system. This paper briefly summarizes the UMTRAP and NRC remedial action technology development. 33 references, 9 figures, 5 tables

  11. Chapter 2. The history of uranium tailings formation in the North of Tajikistan, their current condition. 2.4. Degmai uranium tailings

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

    2012-01-01

    Present article is devoted to Degmai uranium tailings. The history of Degmai uranium tailings is presented. The current condition of uranium tailings is described. During the last 6-7 years, together with IAEA experts, monitoring is permanently carried out and the tailings influence on the environment is defined. Radiation and dosimetric investigation results from Degmai tailing' surface (June 2006) are considered.

  12. Feeding preferences of Lutzomyia longipalpis (Diptera: Psychodidae), the sand fly vector, for Leishmania infantum (Kinetoplastida: Trypanosomatidae).

    Science.gov (United States)

    Macedo-Silva, Virgínia P; Martins, Daniella R A; De Queiroz, Paula Vivianne Souza; Pinheiro, Marcos Paulo G; Freire, Caio C M; Queiroz, José W; Dupnik, Kathryn M; Pearson, Richard D; Wilson, Mary E; Jeronimo, Selma M B; Ximenes, Maria De Fátima F M

    2014-01-01

    Leishmania infantum, the causative agent of visceral leishmaniasis (VL) in Brazil, is spread mostly by the bite of the sand fly Lutzomyia longipalpis (Lutz & Neiva). We trapped sand flies in endemic neighborhoods near Natal, Brazil, where cases of human and dog VL were documented. Amplification of species-specific cytochrome b (Cyt b) genes by polymerase chain reaction revealed that sand flies from rural and periurban areas harbored blood from different sources. The most common source ofbloodmeal was human, but blood from dog, chicken, and armadillo was also present. We tested the preference for a source of bloodmeal experimentally by feeding L. longipalpis F1 with blood from different animals. There were significant differences between the proportion of flies engorged and number of eggs laid among flies fed on different sources, varying from 8.4 to 19 (P < 0.0001). Blood from guinea pig or horse was best to support sand fly oviposition, but human blood also supported sand fly oviposition well. No sand flies fed on cats, and sand flies feeding on the opossum Monodelphis domestica Wagner produced no eggs. These data support the hypothesis that L. longipalpis is an eclectic feeder, and humans are an important source of blood for this sand fly species in periurban areas of Brazil.

  13. Risk assessment of tailings facility dam failure

    OpenAIRE

    Hadzi-Nikolova, Marija; Mirakovski, Dejan; Stefanova, Violeta

    2011-01-01

    This paper presents the consequences of tailings facility dam failure and therefore the needs for its risk assessment. Tailings are fine-grained wastes of the mining industry, output as slurries, due to mixing with water during mineral processing. Tailings dams vary a lot as it is affected by: tailings characteristics and mill output, site characteristics as: topography, hydrology, geology, groundwater, seismicity and available material and disposal methods. The talings which accumulat...

  14. Placement of radium/barium sludges in tailings areas

    International Nuclear Information System (INIS)

    Murphy, K.L.; Multamaki, G.E.

    1980-01-01

    Currently radium is removed from uranium mining and milling effluents by the addition of barium chloride to precipitate the radium as radium/barium sulphate. The precipitate is allowed to settle in sedimentation basins prior to discharge of the effluent. The sedimentation basins are not suitable for final disposal of the sludge, and placement of the sludges in the tailings area has been proposed. The geochemical environment of fresh tailings areas was characterized as an acidic, oxidized surface zone underlain by an alkaline, reduced zone comprising the rest of the tailings. The quantity of sludge produced was estimated to be small relative to the quantity of tailings, and therefor a relatively small amount of radium would be added to the tailings disposal area by the addition of sludge. To confirm whether sludge addition affected radionuclide solubilization, laboratory leaching tests were conducted on slurries of acid leach tailings, and sludge-tailings mixtures. Radium in the (Ra,Ba)SO 4 sludge was at least as stable as radium in the tailings, and the sludge was able to absorb radium released from the tailings. The addition of sludge did not affect uranium and thorium solubilization. From these results it appears that the placement of sludge in tailings areas would not adversely affect the stability of radionuclides in the tailings or sludge. (auth)

  15. Determination of aerosol size distributions at uranium mill tailings remedial action project sites

    International Nuclear Information System (INIS)

    Newton, G.J.; Reif, R.H.; Hoover, M.D.

    1994-01-01

    The U.S. Department of Energy (DOE) has an ongoing program, the Uranium Mill Tailings Remedial Action (UMTRA) Project, to stabilize piles of uranium mill tailings in order to reduce the potential radiological hazards to the public. Protection of workers and the general public against airborne radioactivity during remedial action is a top priority at the UMTRA Project. The primary occupational radionuclides of concern are 230 Th, 226 Ra, 210 Pb, 210 Po, and the short-lived decay products of 222 Rn with 230 Th causing the majority of the committed effective dose equivalent (CEDE) from inhaling uranium mill tailings. Prior to this study, a default particle size of 1.0 μm activity median aerodynamic diameter (AMAD) was assumed for airborne radioactive tailings dust. Because of recent changes in DOE requirements, all DOE operations are now required to use the CEDE methodology, instead of the annual effective dose equivalent (AEDE) methodology, to evaluate internal radiation exposures. Under the transition from AEDE to CEDE, with a 1.0 μm AMAD particle size, lower bioassay action levels would be required for the UMTRA Project. This translates into an expanded internal dosimetry program where significantly more bioassay monitoring would be required at the UMTRA Project sites. However, for situations where the particle size distribution is known to differ significantly from 1.0 μm AMAD, the DOE allows for corrections to be made to both the estimated dose to workers and the derived air concentration (DAC) values. For particle sizes larger than 1.0 μm AMAD, the calculated CEDE from inhaling tailings would be relatively lower

  16. Proceedings of the 15. annual British Columbia MEND ML/ARD workshop : the management of tailings and tailings impoundments

    International Nuclear Information System (INIS)

    2009-02-01

    This Mine Environment Neutral Drainage (MEND) workshop was held to promote the exchange of information and ideas on environmental protection and reclamation associated with mining. The workshop covered a broad spectrum of reclamation issues and the key environmental challenges facing the mining industry, such as acid mine drainage (AMD) control, and metal leaching and acid rock drainage (ML/ARD). The theme for the 2008 workshop was the management of tailings and tailings impoundments. Topics of discussion included hydrogeology and geochemistry; tailings disposal; mitigation; closure plans; and postclosure performance. The emphasis was on full-scale case studies, practical constraints and sustaining successful disposal strategies and remediation. The session on tailings management reviewed overarching policies and practices; methods of subaerial tailings disposal and case studies of tailings management; and detailed investigations of geochemical properties and processes. The conference featured 22 presentations, of which 4 have been catalogued separately for inclusion in this database. refs., tabs., figs

  17. The evolution of tail weaponization in amniotes.

    Science.gov (United States)

    Arbour, Victoria M; Zanno, Lindsay E

    2018-01-31

    Weaponry, for the purpose of intraspecific combat or predator defence, is one of the most widespread animal adaptations, yet the selective pressures and constraints governing its phenotypic diversity and skeletal regionalization are not well understood. Here, we investigate the evolution of tail weaponry in amniotes, a rare form of weaponry that nonetheless evolved independently among a broad spectrum of life including mammals, turtles and dinosaurs. Using phylogenetic comparative methods, we test for links between morphology, ecology and behaviour in extant amniotes known to use the tail as a weapon, and in extinct taxa bearing osseous tail armaments. We find robust ecological and morphological correlates of both tail lashing behaviour and bony tail weaponry, including large body size, body armour and herbivory, suggesting these life-history parameters factor into the evolution of antipredator behaviours and tail armaments. We suggest that the evolution of tail weaponry is rare because large, armoured herbivores are uncommon in extant terrestrial faunas, as they have been throughout evolutionary history. © 2018 The Author(s).

  18. Ecological aspects of microorganisms inhabiting uranium mill tailings

    Science.gov (United States)

    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.

  19. Tailings management for the twenty-first century

    International Nuclear Information System (INIS)

    Frost, S.E.

    1996-01-01

    The evolution of tailings management at Saskatchewan uranium mines is traced from the fifties to the nineties. Some of the problems with past systems are discussed. The new tailings systems now being proposed for the new operations currently undergoing environmental assessment in Saskatchewan are examined in detail. These new systems represent a change in tailings management philosophy, from keeping tailings high and dry on the surface, to placement of tailings in a low-energy regime within the water table. There they are removed from the active surface environment, avoiding future erosion problems, with a reduced likelihood of suffering intrusion from future human or animal activities. (author). 16 refs., 5 figs

  20. A major lineage of non-tailed dsDNA viruses as unrecognized killers of marine bacteria

    Science.gov (United States)

    Kauffman, Kathryn M.; Hussain, Fatima A.; Yang, Joy; Arevalo, Philip; Brown, Julia M.; Chang, William K.; Vaninsberghe, David; Elsherbini, Joseph; Sharma, Radhey S.; Cutler, Michael B.; Kelly, Libusha; Polz, Martin F.

    2018-02-01

    The most abundant viruses on Earth are thought to be double-stranded DNA (dsDNA) viruses that infect bacteria. However, tailed bacterial dsDNA viruses (Caudovirales), which dominate sequence and culture collections, are not representative of the environmental diversity of viruses. In fact, non-tailed viruses often dominate ocean samples numerically, raising the fundamental question of the nature of these viruses. Here we characterize a group of marine dsDNA non-tailed viruses with short 10-kb genomes isolated during a study that quantified the diversity of viruses infecting Vibrionaceae bacteria. These viruses, which we propose to name the Autolykiviridae, represent a novel family within the ancient lineage of double jelly roll (DJR) capsid viruses. Ecologically, members of the Autolykiviridae have a broad host range, killing on average 34 hosts in four Vibrio species, in contrast to tailed viruses which kill on average only two hosts in one species. Biochemical and physical characterization of autolykiviruses reveals multiple virion features that cause systematic loss of DJR viruses in sequencing and culture-based studies, and we describe simple procedural adjustments to recover them. We identify DJR viruses in the genomes of diverse major bacterial and archaeal phyla, and in marine water column and sediment metagenomes, and find that their diversity greatly exceeds the diversity that is currently captured by the three recognized families of such viruses. Overall, these data suggest that viruses of the non-tailed dsDNA DJR lineage are important but often overlooked predators of bacteria and archaea that impose fundamentally different predation and gene transfer regimes on microbial systems than on tailed viruses, which form the basis of all environmental models of bacteria-virus interactions.

  1. Separate groups of dopamine neurons innervate caudate head and tail encoding flexible and stable value memories

    Directory of Open Access Journals (Sweden)

    Hyoung F Kim

    2014-10-01

    Full Text Available Dopamine neurons are thought to be critical for reward value-based learning by modifying synaptic transmissions in the striatum. Yet, different regions of the striatum seem to guide different kinds of learning. Do dopamine neurons contribute to the regional differences of the striatum in learning? As a first step to answer this question, we examined whether the head and tail of the caudate nucleus of the monkey (Macaca mulatta receive inputs from the same or different dopamine neurons. We chose these caudate regions because we previously showed that caudate head neurons learn values of visual objects quickly and flexibly, whereas caudate tail neurons learn object values slowly but retain them stably. Here we confirmed the functional difference by recording single neuronal activity while the monkey performed the flexible and stable value tasks, and then injected retrograde tracers in the functional domains of caudate head and tail. The projecting dopaminergic neurons were identified using tyrosine hydroxylase immunohistochemistry. We found that two groups of dopamine neurons in the substantia nigra pars compacta project largely separately to the caudate head and tail. These groups of dopamine neurons were mostly separated topographically: head-projecting neurons were located in the rostral-ventral-medial region, while tail-projecting neurons were located in the caudal-dorsal-lateral regions of the substantia nigra. Furthermore, they showed different morphological features: tail-projecting neurons were larger and less circular than head-projecting neurons. Our data raise the possibility that different groups of dopamine neurons selectively guide learning of flexible (short-term and stable (long-term memories of object values.

  2. Finite-size effects in the short-time height distribution of the Kardar-Parisi-Zhang equation

    Science.gov (United States)

    Smith, Naftali R.; Meerson, Baruch; Sasorov, Pavel

    2018-02-01

    We use the optimal fluctuation method to evaluate the short-time probability distribution P(H, L, t) of height at a single point, H=h(x=0, t) , of the evolving Kardar-Parisi-Zhang (KPZ) interface h(x, t) on a ring of length 2L. The process starts from a flat interface. At short times typical (small) height fluctuations are unaffected by the KPZ nonlinearity and belong to the Edwards-Wilkinson universality class. The nonlinearity, however, strongly affects the (asymmetric) tails of P(H) . At large L/\\sqrt{t} the faster-decaying tail has a double structure: it is L-independent, -\\lnP˜≤ft\\vert H\\right\\vert 5/2/t1/2 , at intermediately large \\vert H\\vert , and L-dependent, -\\lnP˜ ≤ft\\vert H\\right\\vert 2L/t , at very large \\vert H\\vert . The transition between these two regimes is sharp and, in the large L/\\sqrt{t} limit, behaves as a fractional-order phase transition. The transition point H=Hc+ depends on L/\\sqrt{t} . At small L/\\sqrt{t} , the double structure of the faster tail disappears, and only the very large-H tail, -\\lnP˜ ≤ft\\vert H\\right\\vert 2L/t , is observed. The slower-decaying tail does not show any L-dependence at large L/\\sqrt{t} , where it coincides with the slower tail of the GOE Tracy-Widom distribution. At small L/\\sqrt{t} this tail also has a double structure. The transition between the two regimes occurs at a value of height H=Hc- which depends on L/\\sqrt{t} . At L/\\sqrt{t} \\to 0 the transition behaves as a mean-field-like second-order phase transition. At \\vert H\\vert c-\\vert the slower tail behaves as -\\lnP˜ ≤ft\\vert H\\right\\vert 2L/t , whereas at \\vert H\\vert >\\vert H_c-\\vert it coincides with the slower tail of the GOE Tracy-Widom distribution.

  3. Rehabilitation of uranium tailings impoundments

    International Nuclear Information System (INIS)

    Crawley, A.H.

    1983-01-01

    Under Australian environmental controls relating to the management of uranium tailings, it is no longer acceptable practice to search for a rehabilitation strategy at the end of production when the generation of tailings has ceased. The uranium projects currently in production and those being proposed are tightly regulated by the authorities. The waste management plans must consider site specific factors and must include selection of appropriate disposal sites and design for long term containment. The final encapsulation in engineered facilities must take into account the probable routes to the environment of the tailings. Rehabilitation shoud be undertaken by the mining and milling operators to standards approved by appropriate authorities. Appropriate administrative arrangements are required, by way of technical committees and financial bonds to ensure that agreed standards of rehabilitation may be achieved. Past and present experience with the rehabilitation of uranium tailings impoundments in Australia is discussed

  4. Histone H2A mobility is regulated by its tails and acetylation of core histone tails

    International Nuclear Information System (INIS)

    Higashi, Tsunehito; Matsunaga, Sachihiro; Isobe, Keisuke; Morimoto, Akihiro; Shimada, Tomoko; Kataoka, Shogo; Watanabe, Wataru; Uchiyama, Susumu; Itoh, Kazuyoshi; Fukui, Kiichi

    2007-01-01

    Histone tail domains play important roles in cellular processes, such as replication, transcription, and chromosome condensation. Histone H2A has one central and two tail domains, and their functions have mainly been studied from a biochemical perspective. In addition, analyses based on visualization have been employed for functional analysis of some chromatin proteins. In this study, we analyzed histone H2A mobility in vivo by two-photon FRAP, and elucidated that the histone H2A N- and C-terminal tails regulate its mobility. We found that histone H2A mobility was increased following treatment of host cells with a histone deacetylase inhibitor. Our results support a model in which core histone tails directly regulate transcription by interacting with nucleosome DNA via electrostatic interactions

  5. Cylinder Symmetric Measures with the Tail Property

    NARCIS (Netherlands)

    Balkema, A.A.

    2006-01-01

    Abstract: A Pareto distribution has the property that any tail of the distribution has the same shape as the original distribution. The exponential distribution and the uniform distribution have the tail property too. The tail property characterizes the univariate generalized Pareto distributions.

  6. Radon emanation characteristics of uranium mill tailings

    International Nuclear Information System (INIS)

    Nielson, K.K.; Freeman, H.D.; Hartley, J.N.; Mauch, M.L.; Rogers, V.C.

    1982-01-01

    Radon emanation from uranium mill tailings was examined with respect to the mechanisms of emanation and the physical properties of the tailings which affect emanation. Radon emanation coefficients were measured at ambient moisture on 135 samples from the 1981 field test site at the Grand Junction tailings pile. These coefficients showed a similar trend with moisture to those observed previously with uranium ores, and averaged 0.10 + or - 0.02 at dryness and 0.38 + or - 0.04 for all samples having greater than five weight-percent moisture. Small differences were noted between the maximum values of the coefficients for the sand and slime fractions of the tailings. Separate measurements on tailings from the Vitro tailings pile exhibited much lower emanation coefficients for moist samples, and similar coefficients for dry samples. Alternative emanation measurement techniques were examined and procedures are recommended for use in future work

  7. Heavy mineral concentration from oil sand tailings

    Energy Technology Data Exchange (ETDEWEB)

    Chachula, F.; Erasmus, N. [Titanium Corp. Inc., Regina, SK (Canada)

    2008-07-01

    This presentation described a unique technique to recover heavy minerals contained in the froth treatment tailings produced by oil sand mining extraction operations in Fort McMurray, Alberta. In an effort to process waste material into valuable products, Titanium Corporation is developing technology to recover heavy minerals, primarily zircon, and a portion of bitumen contained in the final stage of bitumen processing. The process technology is being developed to apply to all mined oil sands operations in the Fort McMurray region. In 2004, Titanium Corporation commissioned a pilot research facility at the Saskatchewan Research Council to test dry oil sands tailings. In 2005, a bulk sampling pilot plant was connected to the fresh oil sands tailings pipeline on-site in Fort McMurray, where washed sands containing heavy minerals were processed at a pilot facility. The mineral content in both deposited tailings and fresh pipeline tailings was assessed. Analysis of fresh tailings on a daily basis identified a constant proportion of zircon and higher levels of associated bitumen compared with the material in the deposited tailings. The process flow sheet design was then modified to remove bitumen from the heavy minerals and concentrate the minerals. A newly modified flotation process was shown to be a viable processing route to recover the heavy minerals from froth treatment tailings. 8 refs., 9 tabs., 12 figs.

  8. Tail-assisted pitch control in lizards, robots and dinosaurs.

    Science.gov (United States)

    Libby, Thomas; Moore, Talia Y; Chang-Siu, Evan; Li, Deborah; Cohen, Daniel J; Jusufi, Ardian; Full, Robert J

    2012-01-04

    In 1969, a palaeontologist proposed that theropod dinosaurs used their tails as dynamic stabilizers during rapid or irregular movements, contributing to their depiction as active and agile predators. Since then the inertia of swinging appendages has been implicated in stabilizing human walking, aiding acrobatic manoeuvres by primates and rodents, and enabling cats to balance on branches. Recent studies on geckos suggest that active tail stabilization occurs during climbing, righting and gliding. By contrast, studies on the effect of lizard tail loss show evidence of a decrease, an increase or no change in performance. Application of a control-theoretic framework could advance our general understanding of inertial appendage use in locomotion. Here we report that lizards control the swing of their tails in a measured manner to redirect angular momentum from their bodies to their tails, stabilizing body attitude in the sagittal plane. We video-recorded Red-Headed Agama lizards (Agama agama) leaping towards a vertical surface by first vaulting onto an obstacle with variable traction to induce a range of perturbations in body angular momentum. To examine a known controlled tail response, we built a lizard-sized robot with an active tail that used sensory feedback to stabilize pitch as it drove off a ramp. Our dynamics model revealed that a body swinging its tail experienced less rotation than a body with a rigid tail, a passively compliant tail or no tail. To compare a range of tails, we calculated tail effectiveness as the amount of tailless body rotation a tail could stabilize. A model Velociraptor mongoliensis supported the initial tail stabilization hypothesis, showing as it did a greater tail effectiveness than the Agama lizards. Leaping lizards show that inertial control of body attitude can advance our understanding of appendage evolution and provide biological inspiration for the next generation of manoeuvrable search-and-rescue robots.

  9. Reclamation and closure of an oil sands tailings facility

    Energy Technology Data Exchange (ETDEWEB)

    Sobkowicz, J. [Thurber Engineering Ltd., Calgary, AB (Canada); Morgenstern, N. [Alberta Univ., Edmonton, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of ensuring the successful reclamation of oil sands tailings facilities. Tailings should be reclaimed as mining proceeds in order to avoid an excessive accumulation of fluid fine tailings (FFT). The volume of mature fine tailings (MFT) in ponds should be limited in order to ensure effective tailings management. The reclaimed landforms should have good geotechnical stability and be comprised of self-sustaining native vegetation. Strength is needed to allow for timely capping and initial reclamation, and stiffness is required to minimize future settlement and to allow for the construction of a closure landscape. Reclamation strategies were presented for fines-dominated tailings; sand-depleted tailings; and sand-dominated tailings. Energy Resources Conservation Board (ERCB) criteria for tailings reclamation were discussed, and various monitoring and performance assessment strategies were presented. tabs., figs.

  10. Substance P stimulates the opossum sphincter of Oddi in vitro.

    Science.gov (United States)

    Parodi, J E; Cho, N; Zenilman, M E; Barteau, J A; Soper, N J; Becker, J M

    1990-09-01

    We have previously shown that substance P (SP) regulates sphincter of Oddi (SO) motility in vivo. However, its mechanism of action remains unclear. Our aim was to develop an in vitro model to measure spikeburst (SB) an contractile frequency (CMC) of the SO and to characterize further SP effects. In 16 opossums, SO rings were excised, mounted within a Kreb's tissue bath with bipolar electrodes and force transducers, allowed to equilibrate, and exposed to increasing SP concentrations with washout between each test solution. Spikeburst and CMC frequencies were recorded on a polygraph, quantitated, expressed as differences before and during SP, and statistically analyzed with Student's test. Although SP induced a significant concentration-dependent increase in phasic SB frequency and CMC, the amplitude of concentrations was not affected by SP. A close correlation was found between basal and SP-stimulated SB and CMC, suggesting myoelectric and mechanical coupling. Previous exposure of SO to SP antagonist [D-Arg1, D-Pro2, D-Trp7,9, Leu11]-SP significantly decreased the response to SP. Tetrodotoxin (TTX), did not affect the delta CMC response to SP. In conclusion an in vitro preparation was developed to study the effect of SP on the SO. Substance P increased SB and CMC of the SO in a concentration-dependent fashion, thus acting as a stimulatory peptide. Perfusion of SO rings with SP antagonist had no effect on basal CMC but significantly inhibited the action of SP in a competitive manner. The effect of SP was not altered by TTX. These data suggest that the action of SP on the SO is primarily myogenic.

  11. Canadian experience with uranium tailings disposal

    International Nuclear Information System (INIS)

    Culver, K.B.

    1982-06-01

    During the first years of uranium production in Canada uranium tailings were discharged directly into valleys or lakes near the mill. Treatment with barium chloride to precipitate radium began in 1965 at the Nordic Mine at Elliot Lake, Ontario. In the mid-60s and early 70s water quality studies indicated that discharges from uranium tailings areas were causing degradation to the upper part of the Serpent River water system. Studies into acid generation, revegetation, and leaching of radium were initiated by the mining companies and resulted in the construction of treatment plants at a number of sites. Abandoned tailings sites were revegetated. At hearings into the expansion of the Elliot Lake operations the issue of tailings management was a major item for discussion. As a result federal and provincial agencies developed guidelines for the siting and development of urnaium tailings areas prior to issuing operating licences. Western Canadian uranium producers do not have the acid generation problem of the Elliot Lake operations. The Rabbit Lake mill uses settling ponds followed by filtration. High-grade tailings from Cluff Lake are sealed in concrete and buried. Uranium producers feel that the interim criteria developed by the Atomic Energy Control Board, if adopted, would have a harmful effect on the viability of the Canadian uranium industry

  12. A study of facilities relative to stabilization of uranium mill tailings at Elliot Lake

    International Nuclear Information System (INIS)

    1983-06-01

    The total project capital cost of facilities to stabilize uranium mill tailings at Elliot Lake while producing 350,000 short tons per year of sulphuric acid and 266,000 short tons per year of triple superphosphate is approximately 153 million dollars. This includes pyrite flotation, roasting, acid and phosphate production, site preparation, utilities and project overhead. A new operating credit of 20.43 dollars per short ton of acid is estimated, achieved from the sale of steam and fertilizer. Two alternatives to the above were also examined, as follows: a) Production of 596,000 short tons per year of acid, and the sale of 246,000 short tons which are in excess of the Elliot Lake mill's requirement. The capital cost of this scheme is approximately 89 million dollars, with a net operating credit of 14.97 dollars per short ton of acid. b) Production of only 350,000 short tons per year of acid. This would entail disposal of the excess pyrite floated from the Rio Algom mills. The capital cost of this scheme is approximately 75 million dollars, with an operating cost of 10.47 dollars per short ton of acid

  13. On the average configuration of the geomagnetic tail

    International Nuclear Information System (INIS)

    Fairfield, D.H.

    1978-03-01

    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

  14. Understanding AL-PAM assisted oil sands tailings treatment

    Energy Technology Data Exchange (ETDEWEB)

    Guo, L.; Maham, Y.; Masliyah, J.; Xu, Z. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2010-07-01

    Technologies currently used to treat oil sands tailings include the composite tailings (CT) process and the thickened tailings (TT) or paste technology process. This PowerPoint presentation discussed a flocculation and filtration method used to produce stackable tailings deposits. Magnafloc 1011 and AL-PAM additions were used as part of the filtration technique to produce very dry filter cakes. The effect of AL-PAM molecular weight and aluminum content on tailings treatments was investigated as well as the effect of tailings characteristics on the performance of flocculant-assisted tailings filtration processes. The AL-PAM molecular structure was studied. An experimental study was conducted to determine the effect of various polymer additions on fresh tailings from an oil sands plant. The study showed that the optimum dosage for settling and filtration was lower for higher molecular weight AL-PAM. A higher aluminum content was beneficial for settling. Increases in the aluminum content did not improve filtration rates, but reduced optimal dosages. Step-by-step details of the supernatant filtration process were provided, as well as photographs of the laboratory study. tabs., figs.

  15. The importance of band tail recombination on current collection and open-circuit voltage in CZTSSe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Moore, James E. [Naval Research Laboratory, Washington, DC 20375 (United States); Purdue University, West Lafayette, Indiana 47907 (United States); Hages, Charles J. [Purdue University, West Lafayette, Indiana 47907 (United States); Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Agrawal, Rakesh; Lundstrom, Mark S.; Gray, Jeffery L. [Purdue University, West Lafayette, Indiana 47907 (United States)

    2016-07-11

    Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) solar cells typically exhibit high short-circuit current density (J{sub sc}), but have reduced cell efficiencies relative to other thin film technologies due to a deficit in the open-circuit voltage (V{sub oc}), which prevent these devices from becoming commercially competitive. Recent research has attributed the low V{sub oc} in CZTSSe devices to small scale disorder that creates band tail states within the absorber band gap, but the physical processes responsible for this V{sub oc} reduction have not been elucidated. In this paper, we show that carrier recombination through non-mobile band tail states has a strong voltage dependence and is a significant performance-limiting factor, and including these effects in simulation allows us to simultaneously explain the V{sub oc} deficit, reduced fill factor, and voltage-dependent quantum efficiency with a self-consistent set of material parameters. Comparisons of numerical simulations to measured data show that reasonable values for the band tail parameters (characteristic energy, capture rate) can account for the observed low V{sub oc}, high J{sub sc}, and voltage dependent collection efficiency. These results provide additional evidence that the presence of band tail states accounts for the low efficiencies of CZTSSe solar cells and further demonstrates that recombination through non-mobile band tail states is the dominant efficiency limiting mechanism.

  16. Proceedings of the 2. international oil sands tailings conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    The tailings produced by oil sands extraction processes pose significant threats to the surrounding environment in addition to releasing greenhouse gases (GHGs) into the atmosphere. Recent directives have been established to reduce the amount of tailings produced at oil sands operations, and to ensure that tailings ponds are reclaimed in the most effective manner. This conference provided a forum for researchers and industry experts to discuss issues related to the management and reclamation of oil sands tailings. New technologies for dewatering tailings ponds were presented, and methods of analyzing the chemical properties of tailings were reviewed. The conference was divided into the following 7 sessions: (1) tailings properties, (2) tailings dewatering, (3) new concepts, (4) water and chemistry, (5) soft tailings stabilization and reclamation, (6) water treatment, and (7) new concepts 2. The conference featured 44 presentations, all of which have been catalogued separately for inclusion in this database. tabs., figs.

  17. Sandflies (Diptera: Psychodidae associated with opossum nests at urban sites in southeastern Brazil: a risk factor for urban and periurban zoonotic Leishmania transmission?

    Directory of Open Access Journals (Sweden)

    Andre Antonio Cutolo

    2014-06-01

    Full Text Available Sandflies associated with opossum nests are reported for the first time in the yards of residences located in the urban area of the municipality of Monte Mor, situated in the metropolitan region of Campinas, state of São Paulo, Brazil. Eleven specimens of Evandromyia cortelezzii and one of Evandromyia lenti were captured in two Didelphis albiventris nests. Ev. cortelezzii is considered a secondary vector species for the transmission of Leishmania (Viannia braziliensis and Leishmania (Leishmania infantum in the Neotropics. This association may contribute to the introduction, establishment and maintenance of urban and periurban zoonotic transmission outbreaks of Leishmania and should therefore be investigated further.

  18. Unique structural features facilitate lizard tail autotomy

    DEFF Research Database (Denmark)

    Sanggaard, Kristian W; Danielsen, Carl Chr; Wogensen, Lise

    2012-01-01

    Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed...... that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail...

  19. RAB-like 2 has an essential role in male fertility, sperm intra-flagellar transport, and tail assembly.

    Directory of Open Access Journals (Sweden)

    Jennifer C Y Lo

    Full Text Available A significant percentage of young men are infertile and, for the majority, the underlying cause remains unknown. Male infertility is, however, frequently associated with defective sperm motility, wherein the sperm tail is a modified flagella/cilia. Conversely, a greater understanding of essential mechanisms involved in tail formation may offer contraceptive opportunities, or more broadly, therapeutic strategies for global cilia defects. Here we have identified Rab-like 2 (RABL2 as an essential requirement for sperm tail assembly and function. RABL2 is a member of a poorly characterized clade of the RAS GTPase superfamily. RABL2 is highly enriched within developing male germ cells, where it localizes to the mid-piece of the sperm tail. Lesser amounts of Rabl2 mRNA were observed in other tissues containing motile cilia. Using a co-immunoprecipitation approach and RABL2 affinity columns followed by immunochemistry, we demonstrated that within developing haploid germ cells RABL2 interacts with intra-flagella transport (IFT proteins and delivers a specific set of effector (cargo proteins, including key members of the glycolytic pathway, to the sperm tail. RABL2 binding to effector proteins is regulated by GTP. Perturbed RABL2 function, as exemplified by the Mot mouse line that contains a mutation in a critical protein-protein interaction domain, results in male sterility characterized by reduced sperm output, and sperm with aberrant motility and short tails. Our data demonstrate a novel function for the RABL protein family, an essential role for RABL2 in male fertility and a previously uncharacterised mechanism for protein delivery to the flagellum.

  20. Health risks from uranium mill tailings

    International Nuclear Information System (INIS)

    Russell, J.L.

    1992-01-01

    This paper reviews the risk to public health and the environment from uranium mill tailings. The steps taken by the Environmental Protection Agency (EPA) to reduce this risk from tailing are summarized

  1. Big picture thinking in oil sands tailings disposal

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, J. [Thurber Engineering Ltd., Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of disposing oil sands tailings. Oil sands operators are currently challenged by a variety of legislative and environmental factors concerning the creation and disposal of oil sands tailings. The media has focused on the negative ecological impact of oil sands production, and technical issues are reducing the effect of some mitigation processes. Operators must learn to manage the interface between tailings production and removal, the environment, and public opinion. The successful management of oil sand tailings will include procedures designed to improve reclamation processes, understand environmental laws and regulations, and ensure that the cumulative impacts of tailings are mitigated. Geotechnical investigations, engineering designs and various auditing procedures can be used to develop tailings management plans. Environmental screening and impact assessments can be used to develop sustainable solutions. Public participation and environmental mediation is needed to integrate the public, environmental and technical tailings management strategies. Operators must ensure public accountability for all stakeholders. tabs., figs.

  2. Quasi-steady state aerodynamics of the cheetah tail

    Directory of Open Access Journals (Sweden)

    Amir Patel

    2016-08-01

    Full Text Available 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.

  3. Research on uranium tailings disposal technology at CANMET, Ottawa

    International Nuclear Information System (INIS)

    Skeaff, J.M.; Ritcey, G.M.; Jongejan, A.; Silver, M.

    1982-01-01

    In this paper, results from three continuing investigations at CANMET on uranium tailings management are presented. These investigations are: cleaning of tailings by flotation, conversion of municipal wastes into compost for use as topsoil on uranium tailings, methods for the chemical fixation of uranium tailings and a laboratory determination of the rate of release of environmental contaminants from uranium tailings

  4. Consistency based correlations for tailings consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Azam, S.; Paul, A.C. [Regina Univ., Regina, SK (Canada). Environmental Systems Engineering

    2010-07-01

    The extraction of oil, uranium, metals and mineral resources from the earth generates significant amounts of tailings slurry. The tailings are contained in a disposal area with perimeter dykes constructed from the coarser fraction of the slurry. There are many unique challenges pertaining to the management of the containment facilities for several decades beyond mine closure that are a result of the slow settling rates of the fines and the high standing toxic waters. Many tailings dam failures in different parts of the world have been reported to result in significant contaminant releases causing public concern over the conventional practice of tailings disposal. Therefore, in order to reduce and minimize the environmental footprint, the fluid tailings need to undergo efficient consolidation. This paper presented an investigation into the consolidation behaviour of tailings in conjunction with soil consistency that captured physicochemical interactions. The paper discussed the large strain consolidation behaviour (volume compressibility and hydraulic conductivity) of six fine-grained soil slurries based on published data. The paper provided background information on the study and presented the research methodology. The geotechnical index properties of the selected materials were also presented. The large strain consolidation, volume compressibility correlations, and hydraulic conductivity correlations were provided. It was concluded that the normalized void ratio best described volume compressibility whereas liquidity index best explained the hydraulic conductivity. 17 refs., 3 tabs., 4 figs.

  5. Geophysical applications for oil sand mine tailings management

    Energy Technology Data Exchange (ETDEWEB)

    Parker, D.; Bauman, P. [WorleyParsons, Calgary, AB (Canada)

    2009-07-01

    Geophysical techniques are applied throughout a mine's life cycle to facilitate siting, constructing and monitoring of tailings dumps and ponds. This presentation described 3 case studies from the Athabasca region in northeast Alberta that demonstrated some of the concerns associated with oil sand mine tailings, and the information that geophysical surveys can provide. The objectives of these studies were to determine the lateral and depth extents of elevated conductivities of soil and groundwater that have high salt concentration from the tailings sand pore fluid. Due to high chloride concentrations within the tailings material, salt within the root zone may affect vegetation. A terrain conductivity survey was designed to map the lateral extents of salinity impact, while an electrical resistivity tomography (ERT) survey was used to delineate the tailings sand leachate at depth. The proper management of oil sand tailings facilities is vital to the life cycle of a mine. It was concluded that geophysical techniques can be instrumental in managing several engineering and environmental challenges, from Pleistocene channel mapping, to tailings pond settling characteristics, to reclaiming tailings sands. 1 ref., 7 figs.

  6. Engineering assessment of inactive uranium mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    1981-07-01

    The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, 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 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein 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 VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction 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 $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive.

  7. Engineering assessment of inactive uranium mill tailings

    International Nuclear Information System (INIS)

    1981-07-01

    The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, 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 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein 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 VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction 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 $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive

  8. Four tails problems for dynamical collapse theories

    Science.gov (United States)

    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.

  9. A Note on Upper Tail Behavior of Liouville Copulas

    Directory of Open Access Journals (Sweden)

    Lei Hua

    2016-11-01

    Full Text Available The family of Liouville copulas is defined as the survival copulas of multivariate Liouville distributions, and it covers the Archimedean copulas constructed by Williamson’s d-transform. Liouville copulas provide a very wide range of dependence ranging from positive to negative dependence in the upper tails, and they can be useful in modeling tail risks. In this article, we study the upper tail behavior of Liouville copulas through their upper tail orders. Tail orders of a more general scale mixture model that covers Liouville distributions is first derived, and then tail order functions and tail order density functions of Liouville copulas are derived. Concrete examples are given after the main results.

  10. Turgida turgida (Nematoda: Physalopteridae parasitic in white-bellied opossum, Didelphis albiventris (Marsupialia: Didelphidae, state of Mato Grosso do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Roberta M.P. Humberg

    2011-01-01

    Full Text Available Turgida turgida have been largely reported parasitizing Didelphis species in North and South America based on light microscopy observation. However, the features that differentiate T. turgida from other physalopterid species should be observed using scanning electron microscopy (SEM. A female white-bellied opossum, Didelphis albiventris, arrived dead at the Centro de Reabilitação de Animais Silvestres (CRAS in the municipality of Campo Grande, state of Mato Grosso do Sul, Brazil. During the necropsy, adult nematodes were collected from stomach and intestine. The nematodes were determined to be adult specimens and submitted to SEM for the species determination. This is the first report of T. turgida confirmed by SEM in the Neotropical region and the first report in an urban area in the state of Mato Grosso do Sul, Brazil.

  11. A nonluminescent and highly virulent Vibrio harveyi strain is associated with "bacterial white tail disease" of Litopenaeus vannamei shrimp.

    Directory of Open Access Journals (Sweden)

    Junfang Zhou

    Full Text Available 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.

  12. Solar wind interaction with type-1 comet tails

    International Nuclear Information System (INIS)

    Ershkovich, A.I.

    1977-01-01

    A comet tail is considered as a plasma cylinder separated by a tangential discontinuity surface from the solar wind. Under typical conditions a comet tail boundary is shown to undergo the Kelvin-Helmholtz instability. With infinite amplitude the stabilizing effect of the magnetic field increases, and waves become stable. The proposed model supplies the detailed quantitative description of helical waves observed in type-1 comet tails. This theory enables the evaluation of the comet tail magnetic field by means of the observations of helical waves. The magnetic field in the comet tail turns out to be of the order of the interplanetary field. This conclusion seems to be in accordance with Alfven's idea that the magnetic field in type-1 comet tails is a captured interplanetary field. (Auth.)

  13. Uranium mill tailings

    International Nuclear Information System (INIS)

    McLaren, L.H.

    1982-11-01

    This bibliography contains information on uranium mill tailings included in the Department of Energy's Energy Data Base from January 1981 through October 1982. The abstracts are grouped by subject category as shown in the table of contents. Entries in the subject index also facilitate access by subject, e.g., Mill Tailings/Radiation Hazards. Within each category the arrangement is by report number for reports, followed by nonreports in reverse chronological order. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number. (335 abstracts)

  14. Measuring Fine-Scale White-Tailed Deer Movements and Environmental Influences Using GPS Collars

    International Nuclear Information System (INIS)

    Webb, S.L.; Strickland, B.K.; Demarais, S.; Webb, S.L.; Gee, K.L.; DeYoung, R.W.

    2010-01-01

    Few studies have documented fine-scale movements of ungulate species, including white-tailed deer (Odocoileus virginianus), despite the advent of global positioning system (GPS) technology incorporated into tracking devices. We collected fine-scale temporal location estimates (i.e., 15 min/relocation attempt) from 17 female and 15 male white-tailed deer over 7 years and 3 seasons in Oklahoma, USA. Our objectives were to document fine-scale movements of females and males and determine effects of reproductive phase, moon phase, and short-term weather patterns on movements. Female and male movements were primarily crepuscular. Male total daily movements were 20% greater during rut (7,363? 364) than postrut (6,156 m±260). Female daily movements were greatest during post parturition (3,357 91), followed by parturition (2,902 m±107), and pre parturition (2,682 m±121). We found moon phase had no effect on daily, nocturnal, and diurnal deer movements and fine-scale temporal weather conditions had an inconsistent influence on deer movement patterns within season. Our data suggest that hourly and daily variation in weather events have minimal impact on movements of white-tailed deer in southern latitudes. Instead, routine crepuscular movements, presumed to maximize thermoregulation and minimize predation risk, appear to be the most important factors influencing movements.

  15. Evolution of vertebrate interferon inducible transmembrane proteins

    Directory of Open Access Journals (Sweden)

    Hickford Danielle

    2012-04-01

    Full Text Available Abstract Background Interferon inducible transmembrane proteins (IFITMs have diverse roles, including the control of cell proliferation, promotion of homotypic cell adhesion, protection against viral infection, promotion of bone matrix maturation and mineralisation, and mediating germ cell development. Most IFITMs have been well characterised in human and mouse but little published data exists for other animals. This study characterised IFITMs in two distantly related marsupial species, the Australian tammar wallaby and the South American grey short-tailed opossum, and analysed the phylogeny of the IFITM family in vertebrates. Results Five IFITM paralogues were identified in both the tammar and opossum. As in eutherians, most marsupial IFITM genes exist within a cluster, contain two exons and encode proteins with two transmembrane domains. Only two IFITM genes, IFITM5 and IFITM10, have orthologues in both marsupials and eutherians. IFITM5 arose in bony fish and IFITM10 in tetrapods. The bone-specific expression of IFITM5 appears to be restricted to therian mammals, suggesting that its specialised role in bone production is a recent adaptation specific to mammals. IFITM10 is the most highly conserved IFITM, sharing at least 85% amino acid identity between birds, reptiles and mammals and suggesting an important role for this presently uncharacterised protein. Conclusions Like eutherians, marsupials also have multiple IFITM genes that exist in a gene cluster. The differing expression patterns for many of the paralogues, together with poor sequence conservation between species, suggests that IFITM genes have acquired many different roles during vertebrate evolution.

  16. Isolation of Salmonella enterica and serologic reactivity to Leptospira interrogans in opossums (Didelphis virginiana from Yucatán, México Aislamiento de Salmonella enterica y reactividad serológica a Leptospira interrogans en tlacuaches (Didelphis virginiana de Yucatán, México

    Directory of Open Access Journals (Sweden)

    Hugo Antonio RUIZ-PIÑA

    2002-07-01

    Full Text Available The presence of Salmonella enterica and serologic evidence of infection by Leptospira interrogans, were detected in the opossum Didelphis virginiana in a semi-urban locality of the Yucatán State, México. Ninety-one opossums were captured during the period April 1996 and May 1998. From a total of 17 feces samples, four Salmonella enterica subsp. enterica serotypes (Sandiego, Newport, Anatum, and Minnesota, and one Salmonella enterica subsp. arizonae serovar O44:Z4,Z23:- were isolated. Some opossums presented mixed infections. From 81 sera samples, four (4.9% were positive to antibodies to Leptospira serovars pomona and wolfii. Both animals infected with Salmonella enterica and those serologically positive to Leptospira interrogans were captured in peridomestic habitat. Opossums infected with Salmonella enterica, were captured in dry season, and those seropositive to Leptospira interrogans during the rainy season. The implications of infection and reactivity of these zoonotic pathogens in D. virginiana in the Yucatan state are briefly discussed.La presencia de Salmonella enterica y evidencia serológica de infección por Leptospira interrogans fueron detectadas en tlacuaches de la especie Didelphis virginiana capturados en una localidad semi-urbana del estado de Yucatán, México. Se capturaron 91 marsupiales durante el período de abril de 1996 a mayo de 1998. De un total de 17 muestras de heces, se aislaron cuatro serotipos de Salmonella enterica subsp. enterica (Sandiego, Newport, Anatum y Minnesota y una Salmonella enterica subsp. arizonae serovar O44:Z4,Z23:-. En algunos tlacuaches se registraron infecciones mixtas. De 81 muestras de suero, cuatro (4,9% presentaron reacciones positivas con los serovares pomona y wolffi, ambos pertenecientes al género Leptospira. Los tlacuaches con serología positiva fueron capturados en el hábitat peridomiciliar. Los animales infectados con Salmonella enterica fueron capturados en los períodos de seca y

  17. Heavy Tail Behavior of Rainfall Extremes across Germany

    Science.gov (United States)

    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.

  18. Quasi-steady state aerodynamics of the cheetah tail.

    Science.gov (United States)

    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.

  19. Passive adaptation to stress in adulthood after short-term social instability stress during adolescence in mice.

    Science.gov (United States)

    de Lima, A P N; Massoco, C O

    2017-05-01

    This study reports that short-term social instability stress (SIS) in adolescence increases passive-coping in adulthood in male mice. Short-term SIS decreased the latency of immobility and increased the frequency and time of immobility in tail suspension test. These findings support the hypothesis that adolescent stress can induce a passive adaptation to stress in adulthood, even if it is a short period of stress.

  20. Utilization of mine tailings as partial cement replacement

    DEFF Research Database (Denmark)

    Sigvardsen, Nina Marie; Nielsen, M.R.; Ottosen, Lisbeth M.

    2017-01-01

    Depositing mine tailings entail major economic costs and negative environmental impacts. Thus finding an alternative to depositing is of interest. This study focused on the use of mine tailings as partial cement replacement, thereby preventing depositing the mine tailings. At the same time......, such use would reduce the CO2 emission related to the production of cement. Mine tailings from two different mines Zinkgruvan (Sweden) and Nalunaq (Greenland) were both tested as 5 and 10 % cement replacement. All mortar specimens with mine tailings had lower compressive strength compared to a reference...... compared to a specimen containing a 10 % replacement of cement with coal fly ash, commonly used in Denmark. The compressive strength of specimens containing mine tailings exceeded the compressive strength of the specimen containing coal fly ash, indicating further the amorphous content of volcanic decent...

  1. The Sodium Tail of the Moon

    Science.gov (United States)

    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.

  2. Blast densification trials for oilsands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Port, A. [Klohn Crippen Berger Ltd., Vancouver, BC (Canada); Martens, S. [Klohn Crippen Berger Ltd., Calgary, AB (Canada); Eaton, T. [Shell Canada Ltd., Calgary, AB (Canada)

    2010-07-01

    The Shell Canada Muskeg River Mine External Tailings Facility (ETF) is an upstream constructed tailings facility located near Fort McMurray, Alberta. Raises have incrementally stepped out over the beach since construction of the starter dam and deposition within standing water has left some parts of the beach in a loose state. In order to assess the effectiveness of blast densification, a blast densification trial program that was conducted in 2006 at the ETF. The primary purpose of the test program was to determine the effectiveness of blast densification in tailings containing layers and zones of bitumen. The paper described the site characterization and explosive compaction trial program, with particular reference to test layout; drilling methodology; and blasting and timing sequence. The paper also described the instrumentation, including the seismographs; high pressure electric piezometers; low pressure electric piezometers; vibrating wire piezometers; inclinometers; settlement gauges; and surveys. Trial observations and post-trial observations were also presented. It was concluded that controlled blasting techniques could be used to safely induce liquefaction in localized areas within the tailings deposit, with a resulting increase in the tailings density. 5 refs., 1 tab., 14 figs.

  3. Estimating contaminant discharge rates from stabilized uranium tailings embankments

    International Nuclear Information System (INIS)

    Weber, M.F.

    1986-01-01

    Estimates of contaminant discharge rates from stabilized uranium tailings embankments are essential in evaluating long-term impacts of tailings disposal on groundwater resources. Contaminant discharge rates are a function of water flux through tailings covers, the mass and distribution of tailings, and the concentrations of contaminants in percolating pore fluids. Simple calculations, laboratory and field testing, and analytical and numerical modeling may be used to estimate water flux through variably-saturated tailings under steady-state conditions, which develop after consolidation and dewatering have essentially ceased. Contaminant concentrations in water discharging from the tailings depend on tailings composition, leachability and solubility of contaminants, geochemical conditions within the embankment, tailings-water interactions, and flux of water through the embankment. These concentrations may be estimated based on maximum reported concentrations, pore water concentrations, extrapolations of column leaching data, or geochemical equilibria and reaction pathway modeling. Attempts to estimate contaminant discharge rates should begin with simple, conservative calculations and progress to more-complicated approaches, as necessary

  4. Tailings dams from the perspective of conventional dam engineering

    International Nuclear Information System (INIS)

    Szymanski, M.B.

    1999-01-01

    A guideline intended for conventional dams such as hydroelectric, water supply, flood control, or irrigation is used sometimes for evaluating the safety of a tailings dam. Differences between tailings dams and conventional dams are often substantial and, as such, should not be overlooked when applying the techniques or safety requirements of conventional dam engineering to tailings dams. Having a dam safety evaluation program developed specifically for tailings dams is essential, if only to reduce the chance of potential errors or omissions that might occur when relying on conventional dam engineering practice. This is not to deny the merits of using the Canadian Dam Safety Association Guidelines (CDSA) and similar conventional dam guidelines for evaluating the safety of tailings dams. Rather it is intended as a warning, and as a rationale underlying basic requirement of tailings dam emgineering: specific experience in tailings dams is essential when applying conventional dam engineering practice. A discussion is included that focuses on the more remarkable tailings dam safety practics. It is not addressed to a technical publications intended for such dams, or significantly different so that the use of conventional dam engineering practice would not be appropriate. The CDSA Guidelines were recently revised to include tailings dams. But incorporating tailings dams into the 1999 revision of the CDSA Guidelines is a first step only - further revision is necessary with respect to tailings dams. 11 refs., 2 tabs

  5. Collisional relaxation of electron tail distribution

    International Nuclear Information System (INIS)

    Yamagiwa, Mitsuru; Okamoto, Masao.

    1985-05-01

    Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a 'saddle' point can be created in velocity space owing to upsilon -3 dependence of the deflection rate and a positive slope or a 'dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation. (author)

  6. Why are most EU pigs tail docked?

    DEFF Research Database (Denmark)

    D'eath, R.B.; Niemi, J.K.; Vosough Ahmadi, B.

    2016-01-01

    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...

  7. Unique structural features facilitate lizard tail autotomy.

    Science.gov (United States)

    Sanggaard, Kristian W; Danielsen, Carl Chr; Wogensen, Lise; Vinding, Mads S; Rydtoft, Louise M; Mortensen, Martin B; Karring, Henrik; Nielsen, Niels Chr; Wang, Tobias; Thøgersen, Ida B; Enghild, Jan J

    2012-01-01

    Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

  8. Basic description of tailings from Aitik focusing on mechanical behavior

    OpenAIRE

    Bhanbhro, Riaz; Knutsson, Roger; Rodriguez, Juan; Edeskär, Tommy; Knutsson, Sven

    2013-01-01

    Tailings are artificial granular materials that behave different as compared to natural soil of equal grain sizes. Tailings particle sizes, shapes, gradation and mechanical behavior may influence the performance of tailings dams. Hence it is essential to understand the tailings materials in depth. This article describes present studies being carried out on Aitik tailings. Basic tailings characteristics including specific gravity, phase relationships, particle sizes, particle shapes and direct...

  9. A new procedure for deep sea mining tailings disposal

    OpenAIRE

    Ma, W.; Schott, D.L.; Lodewijks, G.

    2017-01-01

    Deep sea mining tailings disposal is a new environmental challenge related to water pollution, mineral crust waste handling, and ocean biology. The objective of this paper is to propose a new tailings disposal procedure for the deep sea mining industry. Through comparisons of the tailings disposal methods which exist in on-land mining and the coastal mining fields, a new tailings disposal procedure, i.e., the submarine–backfill–dam–reuse (SBDR) tailings disposal procedure, is proposed. It com...

  10. Myxofibrosarcoma: prevalence and diagnostic value of the ''tail sign'' on magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lefkowitz, Robert A.; Landa, Jonathan; Hwang, Sinchun; Panicek, David M. [Memorial Sloan-Kettering Cancer Center, Department of Radiology, New York, NY (United States); Weill Medical College of Cornell University, New York, NY (United States); Zabor, Emily C.; Moskowitz, Chaya S. [Memorial Sloan-Kettering Cancer Center, Department of Epidemiology and Biostatistics, New York, NY (United States); Agaram, Narasimhan P. [Memorial Sloan-Kettering Cancer Center, Department of Pathology, New York, NY (United States)

    2013-06-15

    Myxofibrosarcoma frequently shows curvilinear extensions of high T2 signal that also enhance on magnetic resonance imaging; these ''tails'' represent fascial extension of tumor at histopathological examination. This study was performed to determine whether the tail sign is helpful in distinguishing myxofibrosarcoma from other myxoid-containing neoplasms. The study group consisted of 44 patients with pathologically proven myxofibrosarcoma; the control group consisted of 52 patients with a variety of other myxoid-predominant tumors. Three musculoskeletal radiologists independently evaluated T2-weighted (and/or short-tau inversion recovery) and post-contrast MR images for the presence of one or more enhancing, high-signal intensity, curvilinear projections from the primary mass. Sensitivity and specificity for the diagnosis of myxofibrosarcoma were calculated for each reader. Interobserver variability was assessed with kappa statistic and percentage agreement. A tail sign was deemed present in 28, 30, and 34 cases of myxofibrosarcoma and in 11, 9, and 5 of the controls for the three readers respectively, yielding a sensitivity of 64-77 % and a specificity of 79-90 %. The interobserver agreement was moderate-to-substantial (kappa = 0.626). The tail sign at MRI is a moderately specific and sensitive sign for the diagnosis of myxofibrosarcoma relative to other myxoid-containing tumors. (orig.)

  11. Metal mobilization under alkaline conditions in ash-covered tailings.

    Science.gov (United States)

    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.

  12. The radiological impacts of uranium mill tailings - a review with special emphasis on the tailings at Ranstad in Sweden

    International Nuclear Information System (INIS)

    Snihs, J.O.; Agnedal, P.O.

    1978-07-01

    The environmental impact of uranium mill tailings can be expressed in collective dose commitment and corresponding detriment per MWsub(e).Y energy produced by the uranium which corresponds to the amount of waste of interest. The methods of dose commitment calculations are discussed and it is suggested for the purpose of estimation of the detriment to limit the commitment to 10,000 years. The external radiation from the tailings is easily reduced by covering but in case of a future settlement on the tailings the collective dose commitment will be some hundreds to thousands of manrad/MWsub(e).Y depending on the quality of the uranium ore. The dispersion of dust from uncovered tailings is mainly a local problem and the collective dose commitment for critical tissues in the lung will be less than a manrad/MWsub(e).Y. In the long run the cover may be lost and the resultant collective dose commitment for the critical tissues in the lung will be a few tens of manrad/MWsub(e).Y depending on the quality of the tailings. The effects of global dispersion of the material in the tailings are also discussed

  13. Ilmenite Mineral's Recovery from Beach Sand Tailings

    International Nuclear Information System (INIS)

    Mulaba-Bafubiandi, Antoine F.; Mukendi-Ngalula, David; Waanders, Frans B.

    2002-01-01

    The mineral ilmenite is the major source of rutile for industrial use and is of interest to paint and fertiliser industries. Enormous unutilised tailing dams lie on the eastern coast of the South Africa. Although covered by a simulation of the original indigenous vegetation, these tailings are still ilmenite bearing and of economic value. Tailings emanating from beach sand mineral slimes dams of the Kwazulu-Natal area (South Africa) have been processed. Screening, flotation, spiral concentration and magnetic separation methods were used either separately or successively. The present work sheds light on alternative routes for the extraction of the ilmenite, from these tailings. It moreover points out the usefulness of the Moessbauer spectroscopy in the mineral processing product monitoring. Tailings from the beach sands were used in the present study after the economic industrial minerals zirconia, ilmenite and rutile had been extracted in previous mining operations. About 61% natural ilmenite recovery was observed in the flotation concentrate of a Humphrey Spiral concentrate while a 62% recovery of hematite was found in the flotation tailings. The combination of screening, spiral concentration and magnetic separation, and flotation yielded a product with the highest ilmenite and hematite concentration being 71% and 19%, respectively. A natural ilmenite mineral, containing 87% ilmenite and 13% hematite, could be produced and extracted from the tailings of the flotation process, collected subsequently to the spiral concentration and the initial screening.

  14. Modelling of contaminant migration in acidic groundwater plumes at uranium tailings impoundments: ADNEUT3

    International Nuclear Information System (INIS)

    Cherry, J.A.; Morin, K.A.; Dubrovsky, N.M.

    1984-06-01

    This report describes the creation and application of ADNEUT3, the latest addition to the ADNEUT (Acid-Drainage NEUTralization) family of computer programs for simulating acid-drainage transport and neutralization. The creation of ADNEUT3 involved the expansion of ADNEUT1 to allow variable input conditions such as changing input solution with time, variable initial amounts of minerals through the simulated streamtube, variable velocities through the streamtube, and variable solubilities for relevant minerals dependent on aqueous chemical composition. Concepts for simulating acid-drainage neutralization are reviewed and ADNEUT3 is then applied to a field-study site of acidic contaminant migration from the Nordic Main uranium-tailings impoundment near Elliot Lake, Ontario. A sensitivity study is first implemented to calibrate ADNEUT3 to the results of the 1979 to 1983 field studies. Then ADNEUT3 is used to define probable past conditions at the site which are not reliably known. In particular, ADNEUT3 is used to help identify: 1) the approximate year when acidic seepage began leaving the tailings impoundment (1966-1967), 2) the past chemical composition of the seepage (somewhat more acidic for a short period of time), and 3) the location of the source area within the tailings for the acidic seepage (near the impoundment dam, close to the field site). Finally, ADNEUT3 is used to predict future contaminant migration. Results indicate that hundreds of years are required under present conditions for the most acidic water with associated high levels of contaminants to migrate about 100 m from the tailings impoundment. The cause of this slow movement is the significant neutralization capacity of the aquifer. If acid production within the tailings decreases in the future, migration rates of contaminants will also decrease

  15. Post-fledging movements of white-tailed eagles: Conservation implications for wind-energy development.

    Science.gov (United States)

    Balotari-Chiebao, Fabio; Villers, Alexandre; Ijäs, Asko; Ovaskainen, Otso; Repka, Sari; Laaksonen, Toni

    2016-11-01

    The presence of poorly sited wind farms raises concerns for wildlife, including birds of prey. Therefore, there is a need to extend the knowledge of the potential human-wildlife conflicts associated with wind energy. Here, we report on the movements and habitat use of post-fledging satellite-tagged white-tailed eagles in Finland, where wind-energy development is expected to increase in the near future. In particular, we examine the probability of a fledgling approaching a hypothetical turbine that is placed at different distances from the nest. We found that this probability is high at short distances but considerably decreases with increasing distances to the nest. A utilisation-availability analysis showed that the coast was the preferred habitat. We argue that avoiding construction between active nests and the shoreline, as well as adopting the currently 2-km buffer zone for turbine deployment, can avoid or minimise potential impacts on post-fledging white-tailed eagles.

  16. Chaperone role for proteins p618 and p892 in the extracellular tail development of Acidianus two-tailed virus

    DEFF Research Database (Denmark)

    Scheele, Urte; Erdmann, Susanne; Ungewickell, Ernst J.

    2011-01-01

    The crenarchaeal Acidianus two-tailed virus (ATV) undergoes a remarkable morphological development, extracellularly and independently of host cells, by growing long tails at each end of a spindle-shaped virus particle. Initial work suggested that an intermediate filament-like protein, p800...... the interactions observed between the different protein and DNA components and to explain their possible structural and functional roles in extracellular tail development....

  17. Conception and methodology of a prospective safety report for uranium mills tailings ponds

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, D.; Larue, J.; Fischer- Appelt, K. [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Koln (Germany)

    2006-07-01

    Uranium mill tailings ponds (MTP) stand for the highest potential risk of all legacies from uranium milling. The overall objective of this work was to develop a standardised application document and a working tool for responsible authorities to conduct a continuous safety status description and assessment as well as a prognosis of the respective tailings pond site. - Safety Assessment Principles are based on guide and control values specified in or derived from laws, guidances, norms or standards for the main components who are: technical installations and geo-mechanics, radioactivity, chemical-toxic pollutants. - Data Base: Monitoring data (ground- and seepage water), Radon in near bottom air, Data and information from expertises, reports and technical documents, Site specific data and information (data base A.LAS.KA. / FbU). - Exposure Pathways Analysis. Determination of the radiation exposure to members of the public of different age caused by radioactivity discharges from the tailings pond by means of an authorized calculation procedure. 0.1 to 0.3 mSv/yr with a predominant contribution of ingestion of drinking water (about 80 %). Determination of the hazard resulting from chemical-toxic pollutants according to German regulations. Only relevance of Arsenic via seepage water path. - Forecast of Contaminant Propagation via Groundwater. A three dimensional site specific model was generated to forecast the contaminant distribution in the downstream groundwater flow by means of the available monitoring data. - Safety Assessment. The present status of the tailings pond 'Lengenfeld' was evaluated as to be safe for all three risk components and therefore it is no need for short term measures to minimize hazards or to reduce the contaminants spreading via groundwater. The geochemical environment of the tailings can be regarded as steady, but they are hydraulically tensed by overlaying spar cover. The low permeability of the tailings prevents a significant

  18. Conception and methodology of a prospective safety report for uranium mills tailings ponds

    International Nuclear Information System (INIS)

    Weiss, D.; Larue, J.; Fischer- Appelt, K.

    2006-01-01

    Uranium mill tailings ponds (MTP) stand for the highest potential risk of all legacies from uranium milling. The overall objective of this work was to develop a standardised application document and a working tool for responsible authorities to conduct a continuous safety status description and assessment as well as a prognosis of the respective tailings pond site. - Safety Assessment Principles are based on guide and control values specified in or derived from laws, guidances, norms or standards for the main components who are: technical installations and geo-mechanics, radioactivity, chemical-toxic pollutants. - Data Base: Monitoring data (ground- and seepage water), Radon in near bottom air, Data and information from expertises, reports and technical documents, Site specific data and information (data base A.LAS.KA. / FbU). - Exposure Pathways Analysis. Determination of the radiation exposure to members of the public of different age caused by radioactivity discharges from the tailings pond by means of an authorized calculation procedure. 0.1 to 0.3 mSv/yr with a predominant contribution of ingestion of drinking water (about 80 %). Determination of the hazard resulting from chemical-toxic pollutants according to German regulations. Only relevance of Arsenic via seepage water path. - Forecast of Contaminant Propagation via Groundwater. A three dimensional site specific model was generated to forecast the contaminant distribution in the downstream groundwater flow by means of the available monitoring data. - Safety Assessment. The present status of the tailings pond 'Lengenfeld' was evaluated as to be safe for all three risk components and therefore it is no need for short term measures to minimize hazards or to reduce the contaminants spreading via groundwater. The geochemical environment of the tailings can be regarded as steady, but they are hydraulically tensed by overlaying spar cover. The low permeability of the tailings prevents a significant vertical

  19. Fat-tailed distributions data, diagnostics and dependence

    CERN Document Server

    Cooke, Roger M; Misiewicz, Jolanta

    2014-01-01

    This title is written for the numerate nonspecialist, and hopes to serve three purposes. First it gathers mathematical material from diverse but related fields of order statistics, records, extreme value theory, majorization, regular variation and subexponentiality. All of these are relevant for understanding fat tails, but they are not, to our knowledge, brought together in a single source for the target readership. Proofs that give insight are included, but for most fussy calculations the reader is referred to the excellent sources referenced in the text. Multivariate extremes are not treated. This allows us to present material spread over hundreds of pages in specialist texts in twenty pages. Chapter 5 develops new material on heavy tail diagnostics and gives more mathematical detail. Since variances and covariances may not exist for heavy tailed joint distributions, Chapter 6 reviews dependence concepts for certain classes of heavy tailed joint distributions, with a view to regressing heavy tailed variabl...

  20. Potential Use of Organic- and Hard-Rock Mine Wastes on Aided Phytostabilization of Large-Scale Mine Tailings under Semiarid Mediterranean Climatic Conditions: Short-Term Field Study

    Directory of Open Access Journals (Sweden)

    Claudia Santibañez

    2012-01-01

    Full Text Available The study evaluated the efficacy of organic- and hard-rock mine waste type materials on aided phytostabilization of Cu mine tailings under semiarid Mediterranean conditions in order to promote integrated waste management practices at local levels and to rehabilitate large-scale (from 300 to 3,000 ha postoperative tailings storage facilities (TSFs. A field trial with 13 treatments was established on a TSF to test the efficacy of six waste-type locally available amendments (grape and olive residues, biosolids, goat manure, sediments from irrigation canals, and rubble from Cu-oxide lixiviation piles during early phases of site rehabilitation. Results showed that, even though an interesting range of waste-type materials were tested, biosolids (100 t ha-1 dry weight, d.w. and grape residues (200 t ha-1 d.w., either alone or mixed, were the most suitable organic amendments when incorporated into tailings to a depth of 20 cm. Incorporation of both rubble from Cu-oxide lixiviation piles and goat manure into upper tailings also had effective results. All these treatments improved chemical and microbiological properties of tailings and lead to a significant increase in plant yield after three years from trial establishment. Longer-term evaluations are, however required to evaluate self sustainability of created systems without further incorporation of amendments.

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

    Science.gov (United States)

    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.

  2. UTAP, U Tailings Assessment Program

    International Nuclear Information System (INIS)

    Holmes, Ron

    1998-01-01

    1 - Description of program or function: UTAP carries out probabilistic analyses of the behaviour and environmental effects of uranium mill tailings, following close-out of milling operations. The models have been designed to allow predictions to be made for distances up to 50 kilometers in all directions from the tailings area. The models include features which include the ability to incorporate different receptors and site characteristics and to deal with input parameters which vary with time. 2 - Method of solution: UTAP is composed of a number of modules. These may be classified as either component or control modules. Component modules (or models) are the programs directly concerned with the simulation of a uranium tailings physical system; that is the computer implementation of the mathematical models representing the uranium tailings pile and surrounding environment. Control modules provide the infrastructure for probabilistic analysis using the component modules. These functions include probabilistic sampling of input parameters such as constant, normal, log-normal, uniform, log-uniform, triangular, Weibull, Beta, arbitrary and correlated. The sampling method used is straight Monte Carlo. The radionuclides modelled are: natural uranium, total thorium, radium-226, radon-222 and lead-210. The pH of the reference uranium tailings site and a chained river-lake system are also modelled. For the afore- mentioned radionuclides the following pathways of dose to the receptors modelled: water consumption, fish consumption, radon inhalation, dust inhalation, vegetable consumption, animal produce consumption and ground-shine. 3 - Restrictions on the complexity of the problem: The maximum number of steps through time allowed is 300

  3. Unique structural features facilitate lizard tail autotomy.

    Directory of Open Access Journals (Sweden)

    Kristian W Sanggaard

    Full Text Available Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko and the associated extracellular matrix (ECM rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

  4. Ecological restoration alters microbial communities in mine tailings profiles.

    Science.gov (United States)

    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.

  5. Ecological restoration alters microbial communities in mine tailings profiles

    Science.gov (United States)

    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.

  6. A proactive approach to sustainable management of mine tailings

    Science.gov (United States)

    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

  7. Effects of tail docking and docking length on neuroanatomical changes in healed tail tips of pigs

    DEFF Research Database (Denmark)

    Herskin, M S; Thodberg, K; Jensen, Henrik Elvang

    2015-01-01

    % (n=19); or leaving 25% (n=11) of the tail length on the pigs. The piglets were docked between day 2 and 4 after birth using a gas-heated apparatus, and were kept under conventional conditions until slaughter at 22 weeks of age, where tails were removed and examined macroscopically and histologically...

  8. Oil sands tailings technology : understanding the impact to reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Mamer, M. [Suncor Energy Inc., Fort McMurray, AB (Canada)

    2010-07-01

    This paper discussed tailings management techniques at oil sands mines and their effects on reclamation schedules and outcomes. The layer of mature fine tailings (MFT) that forms in tailings ponds does not settle within a reasonable time frame, requiring more and larger tailings ponds for storing MFT. Consolidated tailings (CT) technology was developed to accelerate the consolidation of MFT, although the process nonetheless takes decades. CT is produced from mixing tailings sand, gypsum, and MFT to create a mixture that will consolidate more quickly and release water. However, CT production is tied to the extraction process, making it applicable only when the plant is operational, and a precise recipe and accurate injection are required for CT to work. In tailings reduction operations (TRO), a new approach to tailings management, MFT is mixed with a polymer flocculant, deposited in thin layers, and allowed to dry. TRO has a significant advantage over CT in that the latter takes up to 30 years to consolidate to a trafficable surface compared to weeks for TRO. TRO allows MFT to be consumed more quickly than it is produced, reducing need to build more tailings ponds, operates independent of plant operations, accelerates the reclamation time frame, and offers enhanced flexibility in final tailings placement sites. TRO also creates a dry landscape, to which well established reclamation techniques can be applied. Dried MFT is a new material type, and research is exploring optimum reclamation techniques. 2 figs.

  9. Screening Assessment of Radionuclide Migration in Groundwater from the “Dneprovskoe” Tailings Impoundment (Dneprodzerzhynsk City) and Evaluation of Remedial Options

    Energy Technology Data Exchange (ETDEWEB)

    Skalskyi, O.; Bugai, D. [Institute of Geological Sciences, National Academy of Sciences of Ukraine (Ukraine); Ryazantsev, V. [State Nuclear Regularity Committee of Ukraine, Kiev (Ukraine)

    2014-05-15

    The paper presents results of mathematical modeling of the hydrogeological conditions at the “Dneprovskoe” (“D”) tailings impoundment –object of the former industrial association of “Pridneprovsky Chemical Plant”, which contains uranium ore processing wastes. This radioactively polluted site is located in a densely populated region (at the outskirts of Dneprodzerginsk City) near the major watercourse of the Ukraine — Dnieper River.The mathematical modeling utilized Visual Modflow (for groundwater flow) and Ecolego (Facilia AB, Sweden) radioecology modeling software (for radionuclide transport).Modeling results indicate the possibility of essential radioactive contamination in future of the phreatic aquifer in alluvial deposits between the “D” tailings and the Dnieper River (mainly due to migration of uranium). Therefore long-term management strategies should preclude water usage from the aquifer in the zone of the in-fluence of the “D” tailings. Filtration discharge of uranium to the Dnepr River does not represent a significant risk due to large dilution by surface waters. The important modeling conclusion is that besides the uranium ore processing wastes inside the tailings, the major source of radionuclide migration to groundwater is represented by contaminated geological deposits below the tailings. This last source was formed due to leakage of wastewaters during the operational period of the “D” tailings (1954–1968). Therefore an exemption and re-disposal of wastes from the “D” tailings to a more safe storage location (proposed by some remedial plans) will not provide significant benefit from the viewpoint of minimizing of radionuclide transport to the groundwater and Dnieper River (especially in short-and medium-term perspective). The rational remedial strategy for the “D” tailings is conservation of tailing wastes in-situ by means of specially designed “zero flux” soil screen, which would minimize infiltration of

  10. Reclamation of copper mine tailings using sewage sludge

    OpenAIRE

    Stjernman Forsberg, Lovisa

    2008-01-01

    Tailings are the fine-grained fraction of waste produced during mining operations. This work was carried out on tailings from the Aitik copper mine in northern Sweden. Establishment of vegetation on the Aitik mine tailings deposit is planned to take place at closure of the mine, using sewage sludge as fertiliser. However, the tailings contain traces of metal sulphides, e.g. pyrite, FeS2, and chalcopyrite, CuFeS2. When the sulphides are oxidised, they start to weather and release metals and st...

  11. Processes for extracting radium from uranium mill tailings

    International Nuclear Information System (INIS)

    Nirdosh, I.; Baird, M.H.; Muthuswami, S.V.

    1987-01-01

    This patent describes a process for the extraction of radium from uranium mill tailings solids including the steps of contacting the tailings with a liquid leaching agent, leaching the tailings therewith and subsequently separating the leachate liquid and the leached solids. The improvement described here is wherein the leaching agent comprises: (a) a complexing agent in an amount of from 2 to 10 times the stoichiometric amount needed to complex the metal ions to be removed thereby from the tailings; and (b) a reducing agent reducing the hydrolysable ions of the metal ions to be removed to their lower oxidation states, the reduction agent being present in an amount from 2 to 10 times the stoichiometric amount needed for reducing the hydrolysable metals present in the tailings

  12. APPLICATION OF POSTFLOTATION TAILINGS IN HYDROENGINEERING STRUCTURES

    Directory of Open Access Journals (Sweden)

    Katarzyna Stefaniak

    2017-01-01

    Full Text Available Economic development stimulated by the increased demand for production of consumer goods and the growing human population result in increasing amounts of various wastes, including tailings. The mining industry in Poland, comprising also mining of non-ferrous metal ores, is a strategic branch of the national economy and at the same time a leading waste producer. Tailings management is a significant problem both in Poland and worldwide. Frequently considerable amounts of wastes are accumulated in mine spoil tips, in areas not always suitable for their deposition, thus leading to the degradation of the surrounding environment. At the huge volume of produced wastes their rational and economically viable management is becoming crucial. On the other hand, depletion of natural aggregate deposits is an important incentive to search for substitutes, which would be suitable for the development of road infrastructure or which could be used in earth structure engineering to construct hydroengineering objects. Since no profitable recovery technologies are available at present, tailings generated by copper mining are deposited in tailings storage facilities. The largest and at the same time the only currently operating facility in Poland is the Żelazny Most Mining Tailings Storage Facility, belonging to KGHM Polska Miedź S.A. The paper presents criteria for material quality and density imposed on the material embedded in the static core of the tailings pond dam. For this purpose studies were conducted to confirm applicability of sorted tailings as a material for the construction of earth structures.

  13. Peptides derived from human galectin-3 N-terminal tail interact with its carbohydrate recognition domain in a phosphorylation-dependent manner

    Energy Technology Data Exchange (ETDEWEB)

    Berbís, M. Álvaro [Chemical and Physical Biology Department, Centro de Investigaciones Biológicas, CSIC, 28040 Madrid (Spain); André, Sabine [Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians University, 80539 Munich (Germany); Cañada, F. Javier [Chemical and Physical Biology Department, Centro de Investigaciones Biológicas, CSIC, 28040 Madrid (Spain); Pipkorn, Rüdiger [Central Peptide Synthesis Unit, German Cancer Research Center, 69120 Heidelberg (Germany); Ippel, Hans [Department of Biochemistry, CARIM, University of Maastricht, Maastricht (Netherlands); Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Mayo, Kevin H. [Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Kübler, Dieter [Biomolecular Interactions, German Cancer Research Center, 69120 Heidelberg (Germany); Gabius, Hans-Joachim [Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians University, 80539 Munich (Germany); Jiménez-Barbero, Jesús, E-mail: jjbarbero@cib.csic.es [Chemical and Physical Biology Department, Centro de Investigaciones Biológicas, CSIC, 28040 Madrid (Spain)

    2014-01-03

    Highlights: •Galectin-3 is composed of a carbohydrate recognition domain and an N-terminal tail. •Synthetic peptides derived from the tail are shown to interact with the CRD. •This interaction is modulated by Ser- and Tyr-phosphorylation of the peptides. -- Abstract: Galectin-3 (Gal-3) is a multi-functional effector protein that functions in the cytoplasm and the nucleus, as well as extracellularly following non-classical secretion. Structurally, Gal-3 is unique among galectins with its carbohydrate recognition domain (CRD) attached to a rather long N-terminal tail composed mostly of collagen-like repeats (nine in the human protein) and terminating in a short non-collagenous terminal peptide sequence unique in this lectin family and not yet fully explored. Although several Ser and Tyr sites within the N-terminal tail can be phosphorylated, the physiological significance of this post-translational modification remains unclear. Here, we used a series of synthetic (phospho)peptides derived from the tail to assess phosphorylation-mediated interactions with {sup 15}N-labeled Gal-3 CRD. HSQC-derived chemical shift perturbations revealed selective interactions at the backface of the CRD that were attenuated by phosphorylation of Tyr 107 and Tyr 118, while phosphorylation of Ser 6 and Ser 12 was essential. Controls with sequence scrambling underscored inherent specificity. Our studies shed light on how phosphorylation of the N-terminal tail may impact on Gal-3 function and prompt further studies using phosphorylated full-length protein.

  14. Peptides derived from human galectin-3 N-terminal tail interact with its carbohydrate recognition domain in a phosphorylation-dependent manner

    International Nuclear Information System (INIS)

    Berbís, M. Álvaro; André, Sabine; Cañada, F. Javier; Pipkorn, Rüdiger; Ippel, Hans; Mayo, Kevin H.; Kübler, Dieter; Gabius, Hans-Joachim; Jiménez-Barbero, Jesús

    2014-01-01

    Highlights: •Galectin-3 is composed of a carbohydrate recognition domain and an N-terminal tail. •Synthetic peptides derived from the tail are shown to interact with the CRD. •This interaction is modulated by Ser- and Tyr-phosphorylation of the peptides. -- Abstract: Galectin-3 (Gal-3) is a multi-functional effector protein that functions in the cytoplasm and the nucleus, as well as extracellularly following non-classical secretion. Structurally, Gal-3 is unique among galectins with its carbohydrate recognition domain (CRD) attached to a rather long N-terminal tail composed mostly of collagen-like repeats (nine in the human protein) and terminating in a short non-collagenous terminal peptide sequence unique in this lectin family and not yet fully explored. Although several Ser and Tyr sites within the N-terminal tail can be phosphorylated, the physiological significance of this post-translational modification remains unclear. Here, we used a series of synthetic (phospho)peptides derived from the tail to assess phosphorylation-mediated interactions with 15 N-labeled Gal-3 CRD. HSQC-derived chemical shift perturbations revealed selective interactions at the backface of the CRD that were attenuated by phosphorylation of Tyr 107 and Tyr 118, while phosphorylation of Ser 6 and Ser 12 was essential. Controls with sequence scrambling underscored inherent specificity. Our studies shed light on how phosphorylation of the N-terminal tail may impact on Gal-3 function and prompt further studies using phosphorylated full-length protein

  15. Geochemical and mineralogical characterization of a neutral, low-sulfide/high-carbonate tailings impoundment, Markušovce, eastern Slovakia.

    Science.gov (United States)

    Hiller, Edgar; Petrák, Marián; Tóth, Roman; Lalinská-Voleková, Bronislava; Jurkovič, L'ubomír; Kučerová, Gabriela; Radková, Anežka; Sottník, Peter; Vozár, Jaroslav

    2013-11-01

    Tailings deposits generated from mining activities represent a potential risk for the aquatic environment through the release of potentially toxic metals and metalloids occurring in a variety of minerals present in the tailings. Physicochemical and mineralogical characteristics of tailings such as total concentrations of chemical elements, pH, ratio of acid-producing to acid-neutralizing minerals, and primary and secondary mineral phases are very important factors that control the actual release of potentially toxic metals and metalloids from the tailings to the environment. The aims of this study are the determination of geochemical and mineralogical characteristics of tailings deposited in voluminous impoundment situated near the village of Markušovce (eastern Slovakia) and identification of the processes controlling the mobility of selected toxic metals (Cu, Hg) and metalloids (As, Sb). The studied tailings have unique features in comparison with the other tailings investigated previously because of the specific mineral assemblage primarily consisting of barite, siderite, quartz, and minor sulfides. To meet the aims, samples of the tailings were collected from 3 boreholes and 15 excavated pits and subjected to bulk geochemical analyses (i.e., determination of chemical composition, pH, Eh, acid generation, and neutralization potentials) combined with detailed mineralogical characterization using optical microscopy, X-ray diffraction (XRD), electron microprobe analysis (EMPA), and micro-X-ray diffraction (μ-XRD). Additionally, the geochemical and mineralogical factors controlling the transfer of potentially toxic elements from tailings to waters were also determined using short-term batch test (European norm EN 12457), sampling of drainage waters and speciation-equilibrium calculations performed with PHREEQC. The tailings mineral assemblage consists of siderite, barite, quartz, and dolomite. Sulfide minerals constitute only a minor proportion of the tailings

  16. Fat-tailed risk about climate change and climate policy

    International Nuclear Information System (INIS)

    Hwang, In Chang; Tol, Richard S.J.; Hofkes, Marjan W.

    2016-01-01

    This paper investigates the role of emissions control in welfare maximization under fat-tailed risk about climate change. We provide a classification of fat tails and discuss the effect of fat-tailed risk on climate policy. One of the main findings is that emissions control may prevent the “strong” tail-effect from arising, at least under some conditions such as bounded temperature increases, low risk aversion, low damage costs, and bounded utility function. More specifically, the fat-tailed risk with respect to a climate parameter does not necessarily lead to an unbounded carbon tax. In this case, the basic principle of cost-benefit analysis maintains its applicability. - Highlights: • A fat tail is classified and the tail effect on climate policy is discussed. • The optimal carbon tax is not necessarily unbounded. • The basic principle of cost-benefit analysis maintains its applicability. • This is a numerical confirmation of the recent theoretical research.

  17. Impact of flocculation on flotation tailing's hydro-cycloning properties

    Directory of Open Access Journals (Sweden)

    Knežević Dinko N.

    2014-01-01

    Full Text Available Research results of hydro-cycloning of flocculated and non-flocculated flotation tailing from the lead and zinc open pit mine 'Suplja stijena', Sula - Montenegro have been shown in this paper. Reason for this research was finding conditions in order to separate fraction that is suitable for embankment erection. Flotation tailings has been tested in the very state that it goes out from the flotation process and tailings which is flocculated by anionic flocculant. The object was to determine the impact of flocculation on properties of hydro-cycloning products and disposal process. In hydro-cycloning process greater underflow mass is being separated with non-flocculated tailing. Values of geomechanical parameters are significantly different, especially hydro-cyclone's underflow. All geomechanical parameters of hydro-cyclone's underflow are suitable for erecting embankment which shall be made from non-flocculated tailing. Underflow drainage of non-flocculated tailing is faster while overflow drainage is slower and problematic with both tailings.

  18. Long-term ecological behaviour of abandoned uranium mill tailings. 1

    International Nuclear Information System (INIS)

    Kalin, M.

    1983-03-01

    Inactive uranium mill tailings were surveyed in the Province of Ontario to describe their surface characteristics, identify naturally invading biota, and determine essential chemical and physical parameters associated with the tailings. Inactive tailings sites can have wet areas, tailings completely covered with water, and dry areas. In the wet areas of most sites, wetland vegetation stands were found which were dominated by species of cattails (Typhaceae), along with some species of rushes (Juncaceae) and sedges (Cyperceae). Dry areas of the tailings exhibited a variety of surface features which are often a reflection of different amelioration efforts. Most of the indigenous species of vascular plants identified on dry areas of the tailings occurred only sporadically. Invading plants found on most sites were the tree species, trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera). Elemental concentration and some physical characteristics of the tailings collected from a depth of 0-20 cm were determined. Uptake of heavy metals and radionuclides were evaluated in trees found in the dry areas and in cattails (Typha latifolia) in the wetland areas. Water bodies on tailings and surface water leaving the tailings, before and after treatment, were characterized in this survey. Aquatic bryophytes have invaded some water bodies on the tailings, and acid tolerant algae were evident in most of the water associated with the tailings. Ecological processes occurring on inactive uranium mill tailings which were identified in this survey are essential in evaluating the long-term fate of these waste sites

  19. Leachability of radioactive constituents from uranium mine tailings

    International Nuclear Information System (INIS)

    Constable, T.W.

    1987-04-01

    A series of long-term studies were conducted both to examine the leachability of major constituents (acidity, TDS) and radioisotopes from uranium mining/milling tailings and settling pond sludges, and to assess the effect of two treatment methods (solidification and vegetation) on leachate characteristics. Four bench-scale experiments were conducted to examine the leachability of: 1) old tailings and those containing a large portion of (Ba,Ra)SO 4 sludges; 2) untreated and solidified (Ba,Ra)SO 4 sludges located at the bottom of settling ponds; 3) new tailings that had been vegetated or solidified; and 4) new tailings subject to varying flow rates. A fifth study was conducted to examine the microbiology of Experiments 2 and 3. In addition, the lysimeter solids remaining in the old tailings at the end of Experiment 1 were characterized through chemical and radionuclide analyses and Scanning Electron Microscope-X-ray Emission and Mossbauer Spectroscopy techniques. This report provides an extensive database of temporal variations in leachate characteristics under both normal and accelerated water application rates. It also presents hypotheses of possible leaching mechanisms in the wastes that could explain the observed data, and conceptual model of tailings leaching processes which integrates the results of all the tailings experiments

  20. How We Tend To Overestimate Powerlaw Tail Exponents

    OpenAIRE

    Nassim N. Taleb

    2012-01-01

    In the presence of a layer of metaprobabilities (from uncertainty concerning the parameters), the asymptotic tail exponent corresponds to the lowest possible tail exponent regardless of its probability. The problem explains "Black Swan" effects, i.e., why measurements tend to chronically underestimate tail contributions, rather than merely deliver imprecise but unbiased estimates.

  1. Electrodialytic remediation of copper mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, A.; Ottpsen, Lisbeth M.

    2005-01-01

    electrodialytic remediation experiments on copper mine tailings. The results show that electric current could remove copper from watery tailing if the potential gradient was higher than 2V/cm during 21 days. With addition of sulphuric acid, the process was enhanced because the pH decreased to around 4...

  2. Moth tails divert bat attack: evolution of acoustic deflection.

    Science.gov (United States)

    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.

  3. Characterization and monitoring of transverse beam tails

    International Nuclear Information System (INIS)

    Seeman, J.T.; Decker, F.J.; Hsu, I.; Young, C.

    1991-05-01

    Low emittance electron beams accelerated to high energy in a linac experience transverse effects (wakefield, filamentation, optics) which produce non-Gaussian projected transverse beam distributions. Characterizations of the beam shapes are difficult because the shapes are asymmetric and change with betatron phase. In this note several methods to describe beam distributions are discussed including an accelerator physics model of these tails. The uses of these characterizations in monitoring the beam emittances in the SLC are described in this paper. First, two dimensional distributions from profile monitor screens are reviewed showing correlated tails. Second, a fitting technique for non-Gaussian one dimensional distributions is used to extract the core from the tail areas. Finally, a model for tail propagation in the linac is given. 3 refs., 6 figs

  4. International experience in tailings pond remediation

    Energy Technology Data Exchange (ETDEWEB)

    MacG. Robertson, A. [Robertson GeoConsultants Ltd., Vancouver (Canada)

    2001-07-01

    Tailings pond remediation is required primarily on mine closure. While mining is an ancient industry, requirement for mine facility remediation is a comparatively new development. Requirement for remediation has come about partly as a result of mans awareness of the environmental impacts of mining and his desire to minimize this, partly, as a result of the ever-increasing scale and production rates of tailings generation and the resulting increased environmental impacts and safety risks. The paper starts with a review of the evolution of mans intolerance of environmental impacts from tailings production and the assignment of liability to remediate such impacts. Many of the tailings ponds currently undergoing remediation were designed and constructed using methods and technology that would be considered inappropriate for new impoundments being designed and developed today. The paper reviews the history of tailings impoundment design and construction practice and the resulting inherent deficiencies that must be remediated. Current practices and future trends in tailings pond remediation are reviewed. The evolution of regulatory requirements is not only in terms of technical and safety criteria, but also in terms of financial and political risk. Perhaps the most substantive driver of risk management is today the requirement for corporate governance at mining company board level and oversight of new project development in the underdeveloped countries by the large financial institutions responsible for funding projects. Embarrassment in the public eye and punishment in the stock markets for poor environmental and safety performance is driving the need for efficient and effective risk management of potential impacts and the remediation to avoid these. A basis for practical risk management is described. (orig.)

  5. International experience in tailings pond remediation

    International Nuclear Information System (INIS)

    Robertson, A.MacG.

    2001-01-01

    Tailings pond remediation is required primarily on mine closure. While mining is an ancient industry, requirement for mine facility remediation is a comparatively new development. Requirement for remediation has come about partly as a result of mans awareness of the environmental impacts of mining and his desire to minimize this, partly, as a result of the ever-increasing scale and production rates of tailings generation and the resulting increased environmental impacts and safety risks. The paper starts with a review of the evolution of mans intolerance of environmental impacts from tailings production and the assignment of liability to remediate such impacts. Many of the tailings ponds currently undergoing remediation were designed and constructed using methods and technology that would be considered inappropriate for new impoundments being designed and developed today. The paper reviews the history of tailings impoundment design and construction practice and the resulting inherent deficiencies that must be remediated. Current practices and future trends in tailings pond remediation are reviewed. The evolution of regulatory requirements is not only in terms of technical and safety criteria, but also in terms of financial and political risk. Perhaps the most substantive driver of risk management is today the requirement for corporate governance at mining company board level and oversight of new project development in the underdeveloped countries by the large financial institutions responsible for funding projects. Embarrassment in the public eye and punishment in the stock markets for poor environmental and safety performance is driving the need for efficient and effective risk management of potential impacts and the remediation to avoid these. A basis for practical risk management is described. (orig.)

  6. Flexible histone tails in a new mesoscopic oligonucleosome model.

    Science.gov (United States)

    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.

  7. Measuring Fine-Scale White-Tailed Deer Movements and Environmental Influences Using GPS Collars

    Directory of Open Access Journals (Sweden)

    Stephen L. Webb

    2010-01-01

    Full Text Available Few studies have documented fine-scale movements of ungulate species, including white-tailed deer (Odocoileus virginianus, despite the advent of global positioning system (GPS technology incorporated into tracking devices. We collected fine-scale temporal location estimates (i.e., 15 min/relocation attempt from 17 female and 15 male white-tailed deer over 7 years and 3 seasons in Oklahoma, USA. Our objectives were to document fine-scale movements of females and males and determine effects of reproductive phase, moon phase, and short-term weather patterns on movements. Female and male movements were primarily crepuscular. Male total daily movements were 20% greater during rut (7,363m±364 than postrut (6,156m±260. Female daily movements were greatest during postparturition (3,357m±91, followed by parturition (2,902m±107, and preparturition (2,682m±121. We found moon phase had no effect on daily, nocturnal, and diurnal deer movements and fine-scale temporal weather conditions had an inconsistent influence on deer movement patterns within season. Our data suggest that hourly and daily variation in weather events have minimal impact on movements of white-tailed deer in southern latitudes. Instead, routine crepuscular movements, presumed to maximize thermoregulation and minimize predation risk, appear to be the most important factors influencing movements.

  8. Assessment of the underground disposal of tailings

    Energy Technology Data Exchange (ETDEWEB)

    Hutt, N M [Morwijk Enterprises Ltd., (Canada); Morin, K A [Normar Enterprises, (Canada)

    1995-06-01

    The Atomic Energy Control Board (AECB) of Canada is facing the issue of long-term disposal of uranium tailings. One option that has not been examined in sufficient detail for the AECB is the retrieval of tailings from surface impoundments and subsequent placement of those tailings in underground workings of mines. This report is structured like a catalogue of facts and information, with each paragraph presenting some concept, concern, theory, or case study involving the retrieval or placement of tailings. All relevant information, findings, interpretations, conclusions, and recommendations gathered during the course of this study are included. The Table of Contents illustrates the striking number of relevant topics and acts like a flowchart or checklist to ensure that an underground-disposal submission by a mining company has addressed relevant topics. This report explains in detail the implications of disturbing surface-impounded tailings for the purpose of placing only some of the volume underground. The cumulative environmental, safety, and monetary liabilities of such a partial scheme can be discouraging in some cases. (author). 244 refs., 47 tabs., 17 figs.

  9. Assessment of the underground disposal of tailings

    International Nuclear Information System (INIS)

    Hutt, N.M.; Morin, K.A.

    1995-06-01

    The Atomic Energy Control Board (AECB) of Canada is facing the issue of long-term disposal of uranium tailings. One option that has not been examined in sufficient detail for the AECB is the retrieval of tailings from surface impoundments and subsequent placement of those tailings in underground workings of mines. This report is structured like a catalogue of facts and information, with each paragraph presenting some concept, concern, theory, or case study involving the retrieval or placement of tailings. All relevant information, findings, interpretations, conclusions, and recommendations gathered during the course of this study are included. The Table of Contents illustrates the striking number of relevant topics and acts like a flowchart or checklist to ensure that an underground-disposal submission by a mining company has addressed relevant topics. This report explains in detail the implications of disturbing surface-impounded tailings for the purpose of placing only some of the volume underground. The cumulative environmental, safety, and monetary liabilities of such a partial scheme can be discouraging in some cases. (author). 244 refs., 47 tabs., 17 figs

  10. Geochemical Characterization of Copper Tailings after Legume Revegetation

    Directory of Open Access Journals (Sweden)

    Justine Perry T. Domingo

    2014-12-01

    Full Text Available Knowledge on the geochemistry of mine tailings is important in understanding the challenges in establishing vegetation cover on tailings dumps and mined out areas. In this study, the mineralogy and trace element composition of copper tailings were examined. Two legume species, Calopogonium mucunoides and Centrosema molle, were utilized to investigate the possible effects of these plants in the geochemical development of mine tailings into soil-like material. The initial mineralogical and chemical analysis of the tailings samples indicated poor conditions for plant growth—minimal levels of major nutrients and organic matter as well as elevated copper concentrations. Despite these conditions, the two legume species exhibited good growth rates. Both legumes have likewise signif icantly reduced heavy metal concentrations in the tailings, indicating the possibility of metal hyperaccumulation in the plant tissue. The mineral composition has been retained even after revegetation; nevertheless, breakdown of primary minerals and subsequent formation of clay minerals were detected. These results provide insights on the transformation of toxic materials into habitable substrates for sustained plant growth.

  11. Short-Term Market Risks Implied by Weekly Options

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Fusari, Nicola; Todorov, Viktor

    a direct way to study volatility and jump risks. Unlike longer-dated options, they are largely insensitive to the risk of intertemporal shifts in the economic environment. Adopting a novel semi-nonparametric approach, we uncover variation in the negative jump tail risk which is not spanned by market......We study short-term market risks implied by weekly S&P 500 index options. The introduction of weekly options has dramatically shifted the maturity profile of traded options over the last five years, with a substantial proportion now having expiry within one week. Such short-dated options provide......" by the level of market volatility and elude standard asset pricing models....

  12. Grouting of uranium mill tailings piles

    International Nuclear Information System (INIS)

    Boegly, W.J. Jr.; Tamura, T.; Williams, J.D.

    1984-03-01

    A program of remedial action was initiated for a number of inactive uranium mill tailings piles. These piles result from mining and processing of uranium ores to meet the nation's defense and nuclear power needs and represent a potential hazard to health and the environment. Possible remedial actions include the application of covers to reduce radon emissions and airborne transport of the tailings, liners to prevent groundwater contamination by leachates from the piles, physical or chemical stabilization of the tailings, or moving the piles to remote locations. Conventional installation of liners would require excavation of the piles to emplace the liner; however, utilization of grouting techniques, such as those used in civil engineering to stabilize soils, might be a potential method of producing a liner without excavation. Laboratory studies on groutability of uranium mill tailings were conducted using samples from three abandoned piles and employing a number of particulate and chemical grouts. These studies indicate that it is possible to alter the permeability of the tailings from ambient values of 10 -3 cm/s to values approaching 10 -7 cm/s using silicate grouts and to 10 -8 cm/s using acrylamide and acrylate grouts. An evaluation of grouting techniques, equipment required, and costs associated with grouting were also conducted and are presented. 10 references, 1 table

  13. Sirenomelia apus with vestigial tail.

    Science.gov (United States)

    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.

  14. Research on the characterization and conditioning of uranium mill tailings. III. Summary of uranium mill tailings conditioning research and implications regarding remedial actions

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Cokal, E.J.; Thode, E.F.; Williams, J.M.

    1983-06-01

    This report summarizes the findings of research on uranium mill tailings conditioning technology development performed for the Department of Energy's (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP). Hazards and risks posed by tailings piles are discussed in relation to the goal of conditioning the tailings to reduce these hazards. The results of our efforts regarding characterization of tailings, removal of radionuclides, mineral recovery, thermal stabilization, and engineering/economic analysis of conditioning are presented. The implications of these results for remedial action plans are discussed and conclusions regarding the applicability of these technologies are also presented

  15. BIOMECHANICS. Why the seahorse tail is square.

    Science.gov (United States)

    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.

  16. Micropore Structure of Cement-Stabilized Gold Mine Tailings

    Directory of Open Access Journals (Sweden)

    Joon Kyu Lee

    2018-03-01

    Full Text Available Mine tailings have often to be stabilized by mixing them with cementing agents. In this study, the pore structure of gold tailings stabilized with Portland cement was evaluated by means of mercury intrusion porosimetry. The investigation was conducted on samples prepared with different fractions of tailings and cement as well as on samples activated with elevated temperature curing and chemical (CaCl2 addition. It was observed that all mixed samples exhibit a mono-modal pore size distribution, indicating that the cement-stabilized tailings are characterized by a single-porosity structure. The results also showed that the higher fraction of tailings and cement leads to a dense and finer pore structure. The total porosity of mixture samples decreases with increasing curing temperature and CaCl2 concentration due to the acceleration of hydration reaction.

  17. The cost of decommissioning uranium mill tailings

    International Nuclear Information System (INIS)

    Lush, D.L.; Lendrum, C.; Hostovsky, C.; Eedy, W.; Ashbrook, A.

    1986-04-01

    This report identifies several key operations that are commonly carried out during decommissioning of tailings areas in the Canadian environment. These operations are unit costed for a generic site to provide a base reference case. The unit costs have also been scaled to the quantities required for the decommissioning of four Canadian sites and these scaled quantities compared with site-specific engineering cost estimates and actual costs incurred in carrying out the decommissioning activities. Variances in costing are discussed. The report also recommends a generic monitoring regime upon which both short- and longer-term environmental monitoring costs are calculated. Although every site must be addressed as a site-specific case, and monitoring programs must be tailored to fit a specific site, it would appear that for the conventional decommissioning and monitoring practices that have been employed to date, costs can be reasonably estimated when site-specific conditions are taken into account

  18. Dewatering Behaviour of Fine Oil Sands Tailings : An Experimental Study

    NARCIS (Netherlands)

    Yao, Y.

    2016-01-01

    Oil sands tailings are a warm aqueous suspension of sand, silt, clay, residual bitumen and naphtha. The tailings are hydraulically transported and stored in tailing ponds where they segregate, with the sand settling from suspension forming beaches and the remaining tailings flowing to the middle of

  19. A Glimpse of the genomic diversity of haloarchaeal tailed viruses

    Directory of Open Access Journals (Sweden)

    Ana eSencilo

    2014-03-01

    Full Text Available Tailed viruses are the most common isolates infecting prokaryotic hosts residing hypersaline environments. Archaeal tailed viruses represent only a small portion of all characterized tailed viruses of prokaryotes. But even this small dataset revealed that archaeal tailed viruses have many similarities to their counterparts infecting bacteria, the bacteriophages. Shared functional homologues and similar genome organizations suggested that all microbial tailed viruses have common virion architectural and assembly principles. Recent structural studies have provided evidence justifying this thereby grouping archaeal and bacterial tailed viruses into a single lineage. Currently there are 17 haloarchaeal tailed viruses with entirely sequenced genomes. Nine viruses have at least one close relative among the 17 viruses and, according to the similarities, can be divided into three groups. Two other viruses share some homologues and therefore are distantly related, whereas the rest of the viruses are rather divergent (or singletons. Comparative genomics analysis of these viruses offers a glimpse into the genetic diversity and structure of haloarchaeal tailed virus communities.

  20. Structural Conservation of the Myoviridae Phage Tail Sheath Protein Fold

    Energy Technology Data Exchange (ETDEWEB)

    Aksyuk, Anastasia A.; Kurochkina, Lidia P.; Fokine, Andrei; Forouhar, Farhad; Mesyanzhinov, Vadim V.; Tong, Liang; Rossmann, Michael G. (SOIBC); (Purdue); (Columbia)

    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 of 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.

  1. Polymer aids for settling and filtration of oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; Energy Resources Conservation Board, Calgary, AB (Canada). Oil Sands Section; Xu, Z.; Masliyah, J.H. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2008-07-01

    Oil sand tailings are segregated into coarse and fine tailings. High volumes of toxic fluids and tailings are created in the process. Tailings ponds are an environmental risk with high operating and maintenance costs. Current commercial technologies uses chemical additions to create recycled water and composite tailings (CT). Researchers are now investigating centrifuged and dry mature fine tailings (MFT). Filtration processes with flocculants are used to separate the tailings into warm recycle water and dried cakes that can be used in reclamation processes. Studies are being conducted to find a polymer than can effectively flocculate and filter whole oil sands tailings. The filtration procedure uses pressure to produce released water. Polymers include magnafloc and Al-PAM polymer concentrations are used in slurry masses. Tests have been conducted to determine the settling rates of the polymers. The tests showed that Al-PAM filtered the tailings effectively. Paraffinic froth treatment tests have also been conducted to determine settling rates. A cake produced with froth treatment tailings of Al-PAM 400 ppm had a water content 42.5 wt per cent. The tests showed that while Magnafloc 1011 is a good settling aid, but a poor filtration addition. Al-PAM aided in both the flocculation and filtration processes. Higher Al-PAM dosages are needed for froth treatment tailings processes. It was concluded that dry cakes are produced with the addition of Al-PAM. tabs., figs.

  2. The problem of abandoned uranium tailings in northern Saskatchewan

    International Nuclear Information System (INIS)

    Swanson, S.; Abouguendia, Z.

    1981-11-01

    Two Saskatchewan tailings sites, Lorado and Gunnar, covering approximately 89 ha., were abandoned in the early 1960s leaving untreated tailings in lakes and depressions. This report reviews the literature on environmental conditions in abandoned uranium tailings and available managmenet and mitigation options, and identifies research requirements essential for proper treatment of these two sites. The recommended management plan includes isolation of the exposed tailings area from surface waters, stabilization of the exposed tailings surfaces, diversion of runoff around tailings, treatment of overflow water before release, and implementation of an environmental monitoring program. Revegetation appears to be a promising stabilization measure, but research is needed into propagation methods of appropriate native species. Studies of the existing geological and hydrological conditions at both sites, detailed characterization of the wastes, field testing of different surface treatment methods, and nutrient cycling investigations are also needed

  3. Asymmetric Extreme Tails and Prospective Utility of Momentum Returns

    NARCIS (Netherlands)

    Stork, P.A.; Gregory-Allen, R.; Lu, H.

    2012-01-01

    We use extreme value theory to analyse the tails of a momentum strategy's return distribution. The asymmetry between the fat left tail and thin right tail strongly reduces a momentum strategy's prospective utility levels. © 2012 Elsevier B.V.

  4. Measurement of radon flux and tailings parameters for quantifying the source term due to radon exhalation from U tailings pile at Jaduguda

    International Nuclear Information System (INIS)

    Sahoo, B.K.; Mayya, Y.S.; Sapra, B.K.; Gaware, J.J.; Khuswaha, H.S.

    2010-01-01

    Full text: The exposures from radon ( 222 Rn) and its decay products have been received considerable attention in the world community because of their adverse health effect. There are various natural and man-made sources of radon present in our environment. Among the man-made sources, the U tailings (waste product from U mining and milling facility) may be considered an important one because it contains significant amount of 226 Ra activity after the U extraction from the ore bodies. These tailings (slurry form) are being impounded into a repository site nearby the facility called 'Tailings Pile' (TP). Significant amount of radon emission takes place from this area by the process of emanation and exhalation. Hence, a study was taken up to quantify the source term arising due to radon emission from uranium tailings pile at Jaduguda in Jharkhand state. In-situ experiments were conducted at 40 locations of the uranium tailings pile in three seasons namely summer, rainy and winter to measure the radon fluxes. The measurements were carried out by deploying a cylindrical chamber, attached to a continuous radon monitor, on the surface of the tailings pile. The dimension of the chamber was selected by using a recently developed two dimensional theory of soil chamber, so that radon concentration growth will be in exponential fashion and the data generated within 2-3 hours of deployment period will be sufficient for accurately deriving the actual radon flux. After the data collection, the fluxes were derived by fitting an exponential growth function to the plot of radon concentration with time. The fluxes were also predicted by diffusion theory using the measured tailings parameters such as 226 Ra content, radon emanation factor, porosity, temperature and moisture. An excellent matching between the predicted and measured fluxes was observed. The validity of diffusion theory in the matrix of U tailings pile provides an alternate method for back-calculating the tailings

  5. A qualitative evaluation of long-term processes governing the behaviour of uranium mill tailings placed in deep lakes

    International Nuclear Information System (INIS)

    McKee, Paul; Snodgrass, William; Lush, D.L.; Ross, P.

    1982-03-01

    The emplacement of uranim mill tailings in deep lakes may provide an acceptable method of tailings disposal at certain sites in Canada. Disposal in a depositional environment typical of deep lakes appears to offer greater prospects for long-term stability than present methods of land-based management. From the regulatory point of view, it is necessary to know which factors should be taken into account in assessing the acceptability of such an approach. This report examines the environmental variables governing the behaviour of radionuclides and trace elements in the groundwater systems, lake water, and finally in the biosphere over the short and long-term. Physical, chemical and biological factors are each considered. Conclusions are presented in terms of points for and against disposal in deep lakes

  6. Limits theorems for tail processes with applications tointermediate quantile estimation

    NARCIS (Netherlands)

    Einmahl, J.H.J.

    1992-01-01

    A description of the weak and strong limiting behaviour of weighted uniform tail empirical and tail quantile processes is given. The results for the tail quantile process are applied to obtain weak and strong functional limit theorems for a weighted non-uniform tail-quantile-type process based on a

  7. Functional morphology of the aardvark tail.

    Science.gov (United States)

    Endo, H; Mori, K; Koyabu, D; Kawada, S; Komiya, T; Itou, T; Koie, H; Kitagawa, M; Sakai, T

    2013-04-01

    The musculoskeletal system of the aardvark (Orycteropus afer) tail was morphologically examined in two adult specimens. The tail musculature comprised three muscular groups, viz. a dorsal sacrocaudal system that consisted of the irregularly oriented Musculus sacrocaudalis dorsalis medialis and M. sacrocaudalis dorsalis lateralis, a lateral inter-vertebral connecting system, and a ventral sacrocaudal system characterized by the thick M. sacrocaudalis ventralis lateralis and M. sacrocaudalis ventralis medialis. Both the dorsal and ventral systems possessed large tendon groups that strengthened the tail structure. Computed tomography (CT) examination showed the presence of large but homogeneous cartilaginous inter-vertebral discs, whereas V-shaped bones were situated at the ventral aspect of the caudal vertebrae at the level of the inter-vertebral discs. CT visualization of the tendons and V-shaped bones in various tail positions suggested that these structures contribute to the tunnel digging action by bearing the trunk weight and lending force when the aardvark are displacing the soil by means of the forelimbs. © 2012 Blackwell Verlag GmbH.

  8. Experiments on a Tail-wheel Shimmy

    Science.gov (United States)

    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.

  9. Uranium tailings in the public eye

    International Nuclear Information System (INIS)

    Lyon, B.

    1976-01-01

    The ORNL field team visits to Grand Junction, Colorado, and to other sources of uranium mill tailings, are described. The radioactive hazards of these tailings, which are principally due to Th, Ra, Rn, and radon daughters, are discussed briefly. Government actions which were taken as a result of public concern are listed. The ORNL Health Physics Division mobile laboratory van and its use in assessing the tailings piles at Salt Lake City and elsewhere are described. The highest γ-ray background found was 155 mRem/y, with levels being as high as 1750 mRem/y near points of public access to piles. Some possible solutions to the problem are discussed

  10. Accuracy of Short Forms of the Dutch Wechsler Preschool and Primary Scale of Intelligence: Third Edition.

    Science.gov (United States)

    Hurks, Petra; Hendriksen, Jos; Dek, Joelle; Kooij, Andress

    2016-04-01

    This article investigated the accuracy of six short forms of the Dutch Wechsler Preschool and Primary Scale of Intelligence-Third edition (WPPSI-III-NL) in estimating intelligent quotient (IQ) scores in healthy children aged 4 to 7 years (N = 1,037). Overall, accuracy for each short form was studied, comparing IQ equivalences based on the short forms with the original WPPSI-III-NL Full Scale IQ (FSIQ) scores. Next, our sample was divided into three groups: children performing below average, average, or above average, based on the WPPSI-III-NL FSIQ estimates of the original long form, to study the accuracy of WPPSI-III-NL short forms at the tails of the FSIQ distribution. While studying the entire sample, all IQ estimates of the WPPSI-III-NL short forms correlated highly with the FSIQ estimates of the original long form (all rs ≥ .83). Correlations decreased significantly while studying only the tails of the IQ distribution (rs varied between .55 and .83). Furthermore, IQ estimates of the short forms deviated significantly from the FSIQ score of the original long form, when the IQ estimates were based on short forms containing only two subtests. In contrast, unlike the short forms that contained two to four subtests, the Wechsler Abbreviated Scale of Intelligence short form (containing the subtests Vocabulary, Similarities, Block Design, and Matrix Reasoning) and the General Ability Index short form (containing the subtests Vocabulary, Similarities, Comprehension, Block Design, Matrix Reasoning, and Picture Concepts) produced less variations when compared with the original FSIQ score. © The Author(s) 2015.

  11. Top Incomes, Heavy Tails, and Rank-Size Regressions

    Directory of Open Access Journals (Sweden)

    Christian Schluter

    2018-03-01

    Full Text Available In economics, rank-size regressions provide popular estimators of tail exponents of heavy-tailed distributions. We discuss the properties of this approach when the tail of the distribution is regularly varying rather than strictly Pareto. The estimator then over-estimates the true value in the leading parametric income models (so the upper income tail is less heavy than estimated, which leads to test size distortions and undermines inference. For practical work, we propose a sensitivity analysis based on regression diagnostics in order to assess the likely impact of the distortion. The methods are illustrated using data on top incomes in the UK.

  12. Predicting the long term stabilisation of uranium mill tailings

    International Nuclear Information System (INIS)

    Trojacek, J.

    2004-01-01

    The long-term stabilization and remediation of uranium mill tailings ponds is an important task for DIAMO. After uranium mining was stopped, DIAMO has to remediate more then 400 ha of tailings ponds at three locations. It is currently planned to cover the surface with low permeability materials with a slope of approx. 3% to protect the interior of the disposal facility from infiltrating rainwater. This entails to cover the free surface of these ponds with several hundred thousand tons of inert material. As a result of this load, the porewater from the tailings is expelled and the body of the impounded materials consolidates. Consolidation of tailings proceeds irregularly, depending on the internal structure of the tailings layers and on the progress of loading. The surface needs to be recontoured for a long time into the future. The topic of the DIAMO project is to predict and optimise the final surface contour of the tailings pond body, and to determine the time schedule and locations for recontouring work. The K1 tailings pond in Dolni Rozinka (Southern Moravia) is a typical example for such task. The average thickness of the tailings layer is around 25 m and the average porewater contents varies from 25 up to 40%. In the years 1998-99 a PHARE pilot project was undertaken that aimed to predict the quantity and quality of drainage and infiltration waters as a function of time. A new investigation programme (field, laboratory and modelling) has been implemented. The range of material properties and distribution of types of tailings was established. Orientation calculations of the tailings consolidation were made for fine slime zone. The results have shown that significant subsidence of the surface is to be expected after loading with inert material for the construction of an interim cover. (author)

  13. Mine tailings dams: Characteristics, failure, environmental impacts, and remediation

    International Nuclear Information System (INIS)

    Kossoff, D.; Dubbin, W.E.; Alfredsson, M.; Edwards, S.J.; Macklin, M.G.; Hudson-Edwards, K.A.

    2014-01-01

    On a global scale demand for the products of the extractive industries is ever increasing. Extraction of the targeted resource results in the concurrent production of a significant volume of waste material, including tailings, which are mixtures of crushed rock and processing fluids from mills, washeries or concentrators that remain after the extraction of economic metals, minerals, mineral fuels or coal. The volume of tailings is normally far in excess of the liberated resource, and the tailings often contain potentially hazardous contaminants. A priority for a reasonable and responsible mining organization must be to proactively isolate the tailings so as to forestall them from entering groundwaters, rivers, lakes and the wind. There is ample evidence that, should such tailings enter these environments they may contaminate food chains and drinking water. Furthermore, the tailings undergo physical and chemical change after they have been deposited. The chemical changes are most often a function of exposure to atmospheric oxidation and tends to make previously, perhaps safely held contaminants mobile and available. If the tailings are stored under water, contact with the atmosphere is substantially reduced, thereby forestalling oxygen-mediated chemical change. It is therefore accepted practice for tailings to be stored in isolated impoundments under water and behind dams. However, these dams frequently fail, releasing enormous quantities of tailings into river catchments. These accidents pose a serious threat to animal and human health and are of concern for extractive industries and the wider community. It is therefore of importance to understand the nature of the material held within these dams, what best safety practice is for these structures and, should the worst happen, what adverse effects such accidents might have on the wider environment and how these might be mitigated. This paper reviews these factors, covering the characteristics, types and magnitudes

  14. Activity, tail loss, growth and survivorship of male Psammodromus algirus

    OpenAIRE

    Salvador Milla, Alfredo; Veiga, José Pablo

    2005-01-01

    Males with autotomized tail were sighted more often and moved longer distances than males with complete tail. There were no significant differences in survival between the two groups. The increase of snout-vent lenght at emergence the following year was significantly lower for males with autotomized tail than for males with complete tail.

  15. Elemental characterization of Tummalapalle uranium mill tailing

    International Nuclear Information System (INIS)

    Patra, A.C.; Sahoo, S.K.; Thakur, V.K.; Dubey, J.S.; Jha, S.K.; Tripathi, R.M.; Sharma, D.B.

    2018-01-01

    Elements are present in environmental matrices at varying concentrations. Their levels may increase due to anthropogenic activities like transportation, industrial activities, agriculture, urbanization and human activities. Trace elements can be classified as potentially toxic (eg. cadmium, arsenic, mercury, lead, nickel), probably essential (eg. cobalt, vanadium) and essential (eg. iron, zinc, copper, selenium, manganese). Due to the expansion of the Indian Nuclear Power Programme, new uranium mining sites are coming up. Mining and milling produce large quantities of low active mill tailings contained in engineered Tailings Ponds. The tailings are amenable for interaction with the geochemical forces and can act as potential sources of contamination. Thus it is necessary to ascertain the concentrations of elements that are present therein. In this paper we aim to characterize the uranium tailings generated from Tummalapalle uranium mining facility in Kadappa district, Andhra Pradesh, India

  16. Application of dry stackable tailings technologies : providing the base for reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Mikula, R.J. [Natural Resources Canada, Devon, AB (Canada). CANMET Energy Technology Centre

    2010-07-01

    The tailings containment structures are some of the largest man made features on the planet. This presentation demonstrated that dry stackable tailings technology may reduce the volume of the accumulated fluid fine tailings. Dry stackable tailings can contribute to boreal forest reclamation and reduce water requirement from the Athabasca River. Much of the water used for the production of each barrel of bitumen is recycled. The water is tied up in the pore spaces of the mineral sand, silt, and clay component which forms the mature fine tailings (MFT) that are contained behind large dykes. Syncrude and Suncor have used a wide variety of technologies to create a dry stackable tailings from this fluid fine tailings substrate. The availability of dry stackable tailings will open options for reclamation strategies that end with the original wetlands or boreal forest. Some of the tailings management options that would lead to a dry stackable tailings naturally also significantly decrease the barrels of water lost with each barrel of bitumen production. These options were discussed along with an analysis of their impact on recycle and pore water quality and quantity. There is an opportunity to remove residual bitumen during the transfer of fluid fine tailings to recover water and create dry stackable tailings. If this bitumen removal is extensive enough, it might be possible to use the dry stackable tailings directly as a reclamation material. tabs., figs.

  17. Asphalt emulsion sealing of uranium mill tailings. 1979 annual report

    International Nuclear Information System (INIS)

    Hartley, J.N.; Koehmstedt, P.L.; Esterl, D.J.; Freeman, H.D.

    1980-06-01

    Uranium mill tailings are a source of low-level radiation and radioactive materials that may be released into the environment. Stabilization or disposal of these tailings in a safe and environmentally sound way is necessary to minimize radon exhalation and other radioactive releases. One of the most promising concepts for stabilizing uranium tailings is being investigated at the Pacific Northwest Laboratory: the use of asphalt emulsion to contain radon and other potentially hazardous materials in uranium tailings. Results of these studies indicate that radon flux from uranium tailings can be reduced by greater than 99% by covering the tailings with an asphalt emulsion that is poured on or sprayed on (3.0 to 7.0 mm thick), or mixed with some of the tailings and compacted to form an admixture seal (2.5 to 15.2 cm) containing 18 wt % residual asphalt

  18. Limit cycle behaviour of the bump-on-tail and ion-acoustic instability

    International Nuclear Information System (INIS)

    Janssen, P.A.E.M.; Rasmussen, J.J.

    1980-12-01

    The nonlinear dynamics of the bump-on-tail and current-driven ion-acoustic instability is considered. The eigenmodes have discrete k because of finite periodic boundary conditions. Increasing a critical parameter (the number density and the electron drift velocity respectively) above its neutral stable value by a small fractional amount Δ 2 , one mode becomes unstable. The nonlinear dynamics of the unstable mode is determined by means of the multiple time scale method. Usually, limit cycle behaviour is found. A short comparison with quasi-linear theory is given, and the results are compared with experiment. (Auth.)

  19. Leachability of metals from gold tailings by rainwater: an ...

    African Journals Online (AJOL)

    Mine leachates from gold tailings impoundments usually contain elevated concentrations of metals and sulphates that impact negatively on water quality. This study was aimed at assessing the leachability of such metals from tailings by rainwater. Oxidised and unoxidised tailings were leached experimentally and through ...

  20. Development in helicopter tail boom strake applications in the US

    Science.gov (United States)

    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.

  1. Tail-robust scheduling using Limited Processor Sharing.

    NARCIS (Netherlands)

    Nair, J.K.; Wierman, A.; Zwart, A.P.

    2010-01-01

    From a rare events perspective, scheduling disciplines that work well under light (exponential) tailed workload distributions do not perform well under heavy (power) tailed workload distributions, and vice versa, leading to fundamental problems in designing schedulers that are robust to

  2. The radiological impacts of uranium mill tailings - A review with special emphasis on the tailings at Ranstad in Sweden

    International Nuclear Information System (INIS)

    Snihs, J.O.

    1978-01-01

    The environmental impact of uranium mill talings can be expressed in collective dose commitment and corresponding detriment per MWe.y energy produced by the uranium which corresponds to the amount of waste interest, The methods of dose commitment calculations are discussed and it is suggested for the purpose of estimation of the detriment to limit the commitment to 10,000 years. The external radiation from the tailings is easily reduced by covering but in case of a future settlement on the tailings the collective dose commitment will be some hundreds to thousands of manrad/MWe.y depending on the quality of the uranium ore. The dispersion of dust from uncovered tailings is mainly a local problem and the collective dose commitment for critical tissues in the lung will be less than a manrad/MWe.y. In the long run the cover may be lost and the resultant collective dose commitment for the critical tissues in the lung will be a few tens of manrad/MWe.y depending on the quality of the tailings. The effects of global dispersion of the material in the tailings are also discussed

  3. Evaluation of inactive uranium mill tailings sites for liner requirements: Characterization and interaction of tailings, soil, and liner materials

    International Nuclear Information System (INIS)

    Relyea, J.F.; Martin, W.J.

    1982-01-01

    This paper summarizes the results of laboratory experiments using soils from Clive, Utah and tailings samples from three inactive uranium processing sites. The results are to be used to predict contaminant behavior for comparison with the regulatory criteria to decide whether a liner is needed. The interactions of leachates with soils and liner material were studied using both batch and column methods. It is determined that batch leaching tests are suitable for screening a large number of tailings samples for relative contaminant concentrations between samples but not for determining contaminant concentrations and release rates in tailings leachate. The results of column leaching tests on samples of tailings from inactive sites indicate that contaminant concentrations are highest in initial leachate from the columns and that concentrations decrease by an order of magnitude or more after one pore volume

  4. Queueing systems with heavy tails (Summary of Ph.D. thesis on the occasion of receiving the Gijs de Leve prize)

    NARCIS (Netherlands)

    Zwart, A.P.

    2003-01-01

    This article gives a short summary of my PhD thesis Queueing Systems with Heavy-tails, winner of the Gijs De Leve prize for the best Dutch thesis in operations research in the period 2000-2002. Apart from the Gijs de Leve prize, this thesis also received the ASML prize, for best thesis in Ihe

  5. A new procedure for deep sea mining tailings disposal

    NARCIS (Netherlands)

    Ma, W.; Schott, D.L.; Lodewijks, G.

    2017-01-01

    Deep sea mining tailings disposal is a new environmental challenge related to water pollution, mineral crust waste handling, and ocean biology. The objective of this paper is to propose a new tailings disposal procedure for the deep sea mining industry. Through comparisons of the tailings disposal

  6. Long-term stabilization of uranium mill tailings

    International Nuclear Information System (INIS)

    Voorhees, L.D.; Sale, M.J.; Webb, J.W.; Mulholland, P.J.

    1983-01-01

    The primary hazard associated with uranium mill tailings is exposure to a radioactive gas, radon-222, the concentration of which has been correlated with the occurrence of lung cancer. Previous studies on radon attenuation conclude that the placement of earthen cover materials over the tailings is the most effective technique for reducing radioactive emissions and dispersal of tailings. The success of such a plan, however, is dependent on ensuring the long-term integrity of these cover materials. Soil erosion from water and wind is the major natural cause of destabilizing earthen cover materials. Field data related to the control of soil loss are limited and only indirectly apply to the problem of isolation of uranium mill tailings over very long time periods (up to 80,000 a). However, sufficient information is available to determine benefits that will result from the changes in specific design variables and to evaluate the need for different design strategies among potential disposal sites. The three major options available for stabilization of uranium mill tailings are: rock cover, soil and revegetation, or a combination of both on different portions of the tailings cover. The optimal choice among these alternatives depends on site-specific characteristics such as climate and local geomorphology and soils, and on design variables such as embankment, heights and slopes, modification of upstream drainage, and revegetation practices. Generally, geomorphic evidence suggests that use of soil and vegetation alone will not be adequate to reduce erosion on slopes greater than about 5 to 9%

  7. Thresher sharks use tail-slaps as a hunting strategy.

    Science.gov (United States)

    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.

  8. TIDAL TAILS OF MINOR MERGERS: STAR FORMATION EFFICIENCY IN THE WESTERN TAIL OF NGC 2782

    International Nuclear Information System (INIS)

    Knierman, Karen; Scowen, Paul; Jansen, Rolf A.; Knezek, Patricia M.; Wehner, Elizabeth

    2012-01-01

    While major mergers and their tidal debris are well studied, they are less common than minor mergers (mass ratios ∼ SFR ) to be several orders of magnitude less than expected from the total gas density. Together with extended FUV+NUV emission from Galaxy Evolution Explorer along the tail, this indicates a low global star formation efficiency in the tidal tail producing lower mass star clusters. The H II region that we observed has a local (few-kiloparsec scale) Σ SFR from Hα that is less than that expected from the total gas density, which is consistent with other observations of tidal debris. The star formation efficiency of this H II region inferred from the total gas density is low, but normal when inferred from the molecular gas density. These results suggest the presence of a very small, locally dense region in the western tail of NGC 2782 or of a low-metallicity and/or low-pressure star-forming region.

  9. Manual for the sampling of uranium mine tailings

    International Nuclear Information System (INIS)

    Feenstra, S.; Reades, D.W.; Cherry, J.A.; Chambers, D.B.; Case, G.G.; Ibbotson, B.G.

    1983-04-01

    The purpose of this manual is to describe the requisite sampling procedures to provide a basis for the application of uniform high-quality standards to detailed geotechnical, hydrogeological, geochemical and air quality measurements at Canadian uranium tailings disposal sites. The report describes the objective and scope of a sampling program, the preliminary data collection, and the procedures for sampling of tailings solids, surface water and seepage, tailings porewater, and wind-blown dust and radon

  10. Price Tails in the Smith and Farmer's Model

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Martin

    2008-01-01

    Roč. 15, č. 25 (2008), s. 31-40 ISSN 1212-074X R&D Projects: GA ČR GA402/07/1113; GA ČR(CZ) GA402/06/1417 Institutional research plan: CEZ:AV0Z10750506 Keywords : limit order market * continuous double auction * price increments * fat tails * tail exponent Subject RIV: AH - Economics http://library.utia.cas.cz/separaty/2008/E/smid-price tails in the smith and farmer's model.pdf

  11. Review of fugitive dust control for uranium mill tailings

    International Nuclear Information System (INIS)

    Li, C.T.; Elmore, M.R.; Hartley, J.N.

    1983-01-01

    An immediate concern associated with the disposal of uranium mill tailings is that wind erosion of the tailings from an impoundment area will subsequently deposit tailings on surrounding areas. Pacific Northwest Laboratory (PNL), under contract to the U.S. Nuclear Regulatory Commission, is investigating the current technology for fugitive dust control. Different methods of fugitive dust control, including chemical, physical, and vegetative, have been used or tested on mill tailings piles. This report presents the results of a literature review and discussions with manufacturers and users of available stabilization materials and techniques

  12. A tale of two tails: Not just skin deep

    Directory of Open Access Journals (Sweden)

    Abhijit Dutta

    2015-01-01

    Full Text Available 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.

  13. Review of fugitive dust control for uranium mill tailings

    Energy Technology Data Exchange (ETDEWEB)

    Li, C.T.; Elmore, M.R.; Hartley, J.N.

    1983-01-01

    An immediate concern associated with the disposal of uranium mill tailings is that wind erosion of the tailings from an impoundment area will subsequently deposit tailings on surrounding areas. Pacific Northwest Laboratory (PNL), under contract to the U.S. Nuclear Regulatory Commission, is investigating the current technology for fugitive dust control. Different methods of fugitive dust control, including chemical, physical, and vegetative, have been used or tested on mill tailings piles. This report presents the results of a literature review and discussions with manufacturers and users of available stabilization materials and techniques.

  14. Estimating impact forces of tail club strikes by ankylosaurid dinosaurs.

    Directory of Open Access Journals (Sweden)

    Victoria Megan Arbour

    Full Text Available BACKGROUND: It has been assumed that the unusual tail club of ankylosaurid dinosaurs was used actively as a weapon, but the biological feasibility of this behaviour has not been examined in detail. Ankylosaurid tail clubs are composed of interlocking vertebrae, which form the handle, and large terminal osteoderms, which form the knob. METHODOLOGY/PRINCIPAL FINDINGS: Computed tomographic (CT scans of several ankylosaurid tail clubs referred to Dyoplosaurus and Euoplocephalus, combined with measurements of free caudal vertebrae, provide information used to estimate the impact force of tail clubs of various sizes. Ankylosaurid tails are modeled as a series of segments for which mass, muscle cross-sectional area, torque, and angular acceleration are calculated. Free caudal vertebrae segments had limited vertical flexibility, but the tail could have swung through approximately 100 degrees laterally. Muscle scars on the pelvis record the presence of a large M. longissimus caudae, and ossified tendons alongside the handle represent M. spinalis. CT scans showed that knob osteoderms were predominantly cancellous, which would have lowered the rotational inertia of the tail club and made it easier to wield as a weapon. CONCLUSIONS/SIGNIFICANCE: Large knobs could generate sufficient force to break bone during impacts, but average and small knobs could not. Tail swinging behaviour is feasible in ankylosaurids, but it remains unknown whether the tail was used for interspecific defense, intraspecific combat, or both.

  15. CT findings of normal pancreatic tail: variety of morphology and location

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hye Seung; Son, San Hoo; Moon, Gae Hyuk; Kim, Hu Ho; Gong Jae Chul; Yang Jae Boum [Inchon Christian Hospital, Inchon (Korea, Republic of); Park, Mee Sook [Jaesung Hospital. (Korea, Republic of)

    1998-02-01

    To determine the morphology and location of normal pancreatic tail, as seen on abdominal CT. A hundred and one patients without pancreatic disease underwent CT scanning. We then determined how to relate the location of the pancreatic tail with the splenic hilum, left kidney, and pancreatic body. We compared the thickness of the tail with that of the body and analysed of the morphology of the tail. Seventy-seven percent of all pancreatic tails were located below the splenic hilum, with 59% of this proportion located 1 to 2 cm below. Fifty percent of tails were located at the level of the uppermost quarter of the left kidney, and a further 27% at the level of the second quarter; 75 % were located in the ventrolateral portion of this kidney and 23% in the ventral portion. In 48% of patients, the pancreatic tail and body were the same thickness, and in a further 48 %, the tail was thicker than the body. In 34% of patients, the tail showed focal bulging, and in another 32%, it tapered smoothly. Forty seven percent of tails were located below the pancreatic body and a further 37% were found at the same level as the body. Abdominal CT scans showed differing morphology and location of the pancreatic tail. The recognition of these variations will diminish speculation as to their true nature. (author). 12 refs., 4 figs.

  16. Studies on the energy metabolism of opossum (Didelphis virginiana) erythrocytes: V. Utilization of hypoxanthine for the synthesis of adenine and guanine nucleotides in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Bethlenfalvay, N.C.; White, J.C.; Chadwick, E.; Lima, J.E. (Fitzsimons Army Medical Center, Aurora, CO (USA))

    1990-06-01

    High pressure liquid radiochromatography was used to test the ability of opossum erythrocytes to incorporate tracer amounts of (G-{sup 3}H) hypoxanthine (Hy) into ({sup 3}H) labelled triphosphates of adenine and guanine. In the presence of supraphysiologic (30 mM) phosphate which is optimal for PRPP synthesis, both ATP and GTP are extensively labelled. When physiologic (1 mM) medium phosphate is used, red cells incubated under an atmosphere of nitrogen accumulate ({sup 3}H) ATP in a linear fashion suggesting ongoing PRPP synthesis in red cells whose hemoglobin is deoxygenated. In contrast, a lesser increase of labelled ATP is observed in cells incubated under oxygen, suggesting that conditions for purine nucleotide formation from ambient Hy are more favorable in the venous circulation.

  17. Studies on the energy metabolism of opossum (Didelphis virginiana) erythrocytes: V. Utilization of hypoxanthine for the synthesis of adenine and guanine nucleotides in vitro

    International Nuclear Information System (INIS)

    Bethlenfalvay, N.C.; White, J.C.; Chadwick, E.; Lima, J.E.

    1990-01-01

    High pressure liquid radiochromatography was used to test the ability of opossum erythrocytes to incorporate tracer amounts of [G- 3 H] hypoxanthine (Hy) into [ 3 H] labelled triphosphates of adenine and guanine. In the presence of supraphysiologic (30 mM) phosphate which is optimal for PRPP synthesis, both ATP and GTP are extensively labelled. When physiologic (1 mM) medium phosphate is used, red cells incubated under an atmosphere of nitrogen accumulate [ 3 H] ATP in a linear fashion suggesting ongoing PRPP synthesis in red cells whose hemoglobin is deoxygenated. In contrast, a lesser increase of labelled ATP is observed in cells incubated under oxygen, suggesting that conditions for purine nucleotide formation from ambient Hy are more favorable in the venous circulation

  18. Electrodialytic Remediation of Copper Mine Tailings

    DEFF Research Database (Denmark)

    Hansen, H.K.; Rojo, A.; Ottosen, L.M.

    2012-01-01

    This work compares and evaluates sixteen electrodialytic laboratory remediation experiments on copper mine tailings. Different parameters were analysed, such as remediation time, addition of desorbing agents, and the use of pulsed electrical fields.......This work compares and evaluates sixteen electrodialytic laboratory remediation experiments on copper mine tailings. Different parameters were analysed, such as remediation time, addition of desorbing agents, and the use of pulsed electrical fields....

  19. Utilisation of iron ore tailings as aggregates in concrete

    Directory of Open Access Journals (Sweden)

    Francis Atta Kuranchie

    2015-12-01

    Full Text Available Sustainable handling of iron ore tailings is of prime concern to all stakeholders who are into iron ore mining. This study seeks to add value to the tailings by utilising them as a replacement for aggregates in concrete. A concrete mix of grade 40 MPa was prepared in the laboratory with water–cement ratio of 0.5. The concrete were cured for 1, 2, 3, 7, 14 and 28 days. The properties of the concrete such as workability, durability, density, compressive strength and indirect tensile strength were tested. A controlled mix of concrete was also prepared in similar way using conventional materials and the results were compared with the tailings concrete. It was found that the iron ore tailings may be utilised for complete replacement for conventional aggregates in concrete. The iron ore tailings aggregates concrete exhibited a good mechanical strength and even in the case of compressive strength, there was an improvement of 11.56% over conventional aggregates concrete. The indirect tensile strength did not improve against the control mix due high content of fines in the tailings aggregates but showed 4.8% improvement compared with the previous study where the conventional fine aggregates was partially replaced by 20% with iron ore tailings.

  20. An M-estimator of multivariate tail dependence

    NARCIS (Netherlands)

    Krajina, A.

    2010-01-01

    AN M-ESTIMATOR OF TAIL DEPENDENCE. Extreme value theory is the part of probability and statistics that provides the theoretical background for modeling events that almost never happen. The estimation of the dependence between two or more such unlikely events (tail dependence) is the topic of this

  1. Some properties of Suncor oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Guo, C.; Wells, P.S. [Suncor Energy, Fort McMurray, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed a pond assessment program conducted by Suncor to determine the properties of mature fine tailings (MFT) and composite tailings (CT) at reclaimed and unreclaimed sites. Mudline and sonar depth sounding techniques were used to determine solids contents. A wire line sampler provided point depth samples used for laboratory analyses. Continuous drill samples were obtained in order to characterize bottom fines and clay content. A flow penetration tests was used to determine the undrained shear strength of the soft tailings. A 3-D block model was then used to estimate soft material properties and to generate material distribution volumes and tonnages for different property ranges. The study showed that the block modelling techniques provide a more accurate tailings pond assessment than traditional approaches. While slow, ongoing static consolidation was observed, surface capping and artificial dewatering are required to provide trafficable ground for the final reclamation of the sites. tabs., figs.

  2. Flotation tailings as a raw material for ceramic building materials

    Energy Technology Data Exchange (ETDEWEB)

    Burmistrov, V N; Karpunina, T I; Smolin, V N

    1986-02-01

    The VNIIstrom research institute developed a method for utilizing flotation tailings for production of bricks. Tailings are dewatered using filter presses. After dewatering, moisture content in the tailings ranges from 25 to 26%. Tailings are mixed with chamotte with a grain size to 2 mm. Using 30% chamotte improves mechanical and physical properties of the bricks and reduces energy consumption of brick firing. Tailings mixed with chamotte are granulated and dried on a conveyor. Granules with moisture content reduced to the optimum level are mixed a second time and formed in a press. The bricks are fired in a tunnel kiln with modified design. The bricks made of flotation tailings mixed with 30% chamotte are characterized by mechanical properties comparable to those of high quality bricks made of conventional materials.

  3. General review of the state of uranium milling tailings in Ukraine

    International Nuclear Information System (INIS)

    Holubiev, V.

    2002-01-01

    The mining and milling of uranium ore are produced in Ukraine since 1948. During this time eleven tailings were formed at the large territory in the region of cities Zhovty Vody and Dnepropetrovsk. One tailing is now in operation. Other ten tailings are under conservation and are producing environmental impact of different extent. Any of tailings was not subjected to recovery. By means of the enterprises, which have on their territory tailings, the monitoring is carried out for radionuclides coming in underground waters. The samples of underground water are taken from wells that are located at the tailing perimeter. The list of tailings, quantity of stored material, and radionuclides activity are submitted in the table. The supervision shows, that all tailings to some extent are the issue of radionuclides diffusion. The brief characteristic of the largest tailings is submitted. The supervision shows that all tailings to some extent are the issue of radionuclides diffusion. The brief characteristic of the largest tailings is submitted. Most of tailings are located in natural folds of a region relief, however one of them (KBG) is arranged in career with depth 60-65 m. Iron ore was mined in this career and career is located on distance 2.5 km from an inhabited zone. Career was not equipped by anti filtration barriers before it was started to fill it with sludge. In total 12.4·10 6 m 3 of tails is placed in it with general activity about 1 PBq. When tailing's filling was finished at 1991 its surface was covered by 1,7 m layer of loamy soil. The tailing creation resulted in change of hydro-geological conditions of a platform and in appearance of man-caused water-bearing horizon. The halo of pollution of underground waters is moving from the bounds of the site towards the inhabited zone of Zhovty Vody city. Now polluted by radionuclides water is detected at the distance of 1.5 km from tailing. According to forecast estimations in 15 years the pollution will move forward

  4. The hydrogeochemistry of four inactive tailings impoundments: Perspectives on tailings pore-water evolution

    International Nuclear Information System (INIS)

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

    1987-01-01

    Extensive hydrogeochemical investigations are currently underway at three inactive tailings impoundments in Canada. These programs include detailed measurements of pore-water and gas-phase geochemistry through the vadose zone and the groundwater zone. An extensive piezometer network has been installed at each location to monitor the groundwater flow regime. All of the impoundments studied have been inactive for 15 to 25 years, sufficient time for extensive tailings pore-water evolution. The study areas include a very high-sulfide impoundment, a low-sulfide, high-carbonate impoundment, a low-sulfide, very low-carbonate impoundment, and a moderately high-sulfide impoundment. The pore water at each of the sites has evolved in a distinctly different and characteristic manner, representing broad styles of tailings pore-water evolution. At the high sulfide impoundment the oxidation of sulfide minerals has resulted in low pH, high redox potential conditions, with Fe 2+ concentrations in excess of 60,000 mg/L. At a depth of about 40 cm a 10 cm thick layer of ferrous and calcium sulfate minerals has precipitated. This hardpan layer limits the downward movement of O 2 and infiltrating pore waters. As a result, the pore water chemistry, both above and below the hardpan layer, has remained relatively unchanged over the past 10 years. The low-sulfide, high-carbonate tailings are sufficiently well buffered that no low pH conditions are present. The high pH conditions limit the concentrations of the metals released by sulfide mineral oxidation to levels that are two or three orders of magnitude less than is observed at the high-sulfide site. Pore waters at the low-sulfide, low-carbonate site were sampled by other researchers from the University of Waterloo

  5. Variation of Pore Water Pressure in Tailing Sand under Dynamic Loading

    Directory of Open Access Journals (Sweden)

    Jia-xu Jin

    2018-01-01

    Full Text Available Intense vibration affects the pore water pressure in a tailing dam, with the tendency to induce dam liquefaction. In this study, experiments were performed wherein model tailing dams were completely liquefied by sustained horizontal dynamic loading to determine the effects of the vibration frequency, vibration amplitude, and tailing density on the pore water pressure. The results revealed four stages in the increase of the tailing pore water pressure under dynamic loading, namely, a slow increase, a rapid increase, inducement of structural failure, and inducement of complete liquefaction. A lower frequency and smaller amplitude of the vibration were found to increase the time required to achieve a given pore water pressure in dense tailings. Under the effect of these three factors—vibration frequency and amplitude and tailing density—the tailing liquefaction time varied nonlinearly with the height from the base of the tailing dam, with an initial decrease followed by an increase. The pore pressure that induced structural failure also gradually decreased with increasing height. The increase in the tailing pore pressure could be described by an S-shaped model. A complementary multivariate nonlinear equation was also derived for predicting the tailing pore water pressure under dynamic loading.

  6. Near-threshold quantization and scattering for deep potentials with attractive tails

    International Nuclear Information System (INIS)

    Eltschka, Christopher; Moritz, Michael J.; Friedrich, Harald

    2000-01-01

    Near-threshold properties of bound and continuum states in a deep potential with an attractive tail depend essentially on a few 'tail parameters', which are determined by the properties of the potential tail beyond the region of r-values where WKB wavefunctions are accurate solutions of the Schroedinger equation. One of these tail parameters is a length parameter which defines the singular contribution to the level density just below threshold and the reflectivity of the tail of the potential just above threshold; another is a phase difference which, together with the length parameter, determines the mean scattering length. The near-threshold quantization rule and the actual scattering length are determined by the tail parameters together with a dimensionless constant depending on the zero-energy value of the WKB action integral. We study potentials with tails consisting of two inverse-power terms, V(r)∼-C α /r α -C α 1 /r α 1 ,α 1 >α>2and we derive exact analytical expressions for the tail parameters in the special case α 1 =2(α-1). This enables us to demonstrate the effect of a significant non-homogeneity of the potential tail on the results derived previously for homogeneous tails. (author)

  7. Two active galaxies with tidal tails and companions

    International Nuclear Information System (INIS)

    Keel, W.C.

    1985-01-01

    Spectroscopic, imaging, and radio observations of the tidally disturbed active systems VV 144 and I Zw 96 are presented, and indicate that the prominent optical extensions seen in both cases represent tidal tails rather than matter ejected from their nuclei (jets). This conclusion is based on the presence of stellar spectral features in the tails, lack of significant ionized gas over most of their length, and lack of radio emission outside the nuclei. Discrete knots in these tails are identified with remnant cores of the companion galaxies responsible for the morphological disturbances of the main galaxies and perhaps contributing to their nuclear activity. In both cases, the dynamics of the interactions are unusual in nature or viewing geometry. VV 144 is seen in the common plane of interaction and disk rotation, appearing strongly foreshortened. I Zw 96 shows tails associated with two companions; each is accompanied by changes in tail structure. This may be the result of a binary system of spirals colliding with a giant elliptical galaxy. 18 references

  8. Interactions of tailings leachate with local liner materials found at Canonsburg, Pennsylvania

    International Nuclear Information System (INIS)

    Dodson, M.E.; Gee, G.W.; Serne, R.J.

    1984-04-01

    The mill tailings site at Canonsburg, Pennsylvania is the first mill site to receive remedial action under the Department of Energy's Uranium Mill Tailings Remedial Action Program. Part of this remedial action will require excavating the 53,500 m 3 (70,000 yd 3 ) of tailings on the site having a specific activity exceeding 100 pCi/g, and encapsulating these contaminated tailings in a clay-lined cell. As part of the remedial action effort, Pacific Northwest Laboratory has been studying the interactions of tailings and tailings leachate with locally occurring clays proposed for liner materials. These studies include physical and chemical characterization of amended and unamended local clays, chemical characterization of the tailings, column studies of tailings leached with deionized water, and column studies of clays contacted with tailings solutions to determine the attenuation properties of the proposed liner materials. Column studies of tailings leached with deionized water indicated that the Canonsburg tailings could represent a source of soluble radium-226 and uranium-238, several trace metals, cations, and the anions SO 4 , NO 3 , and Cl. Of these soluble contaminants, uranium-238, radium-226, the trace metals As and Mo, and the anions F and SO 4 were present at levels exceeding maximum concentration levels in the tailings leaching column effluents. However, local clays, both in amended and unamended form were effective in attenuating contaminant migration. The soil amendments tested failed to increase radium attenuation. The tailings leaching studies indicated that the tailings will produce leachates of neutral pH and relatively low contaminant levels for at least 200 years. We believe that compacting the tailings within the encapsulation cell will help to reduce leaching of contaminants from the liner system, since very low permeabilities ( -8 cm/s) were observed for even slightly compacted tailings materials

  9. Proteomic and biochemical analyses of short-tailed pit viper (Gloydius brevicaudus) venom: age-related variation and composition-activity correlation.

    Science.gov (United States)

    Gao, Jian-Fang; Wang, Jin; He, Ying; Qu, Yan-Fu; Lin, Long-Hui; Ma, Xiao-Mei; Ji, Xiang

    2014-06-13

    We conducted an in-depth analysis of the proteomic and biochemical profiles of the venom of neonate and adult short-tailed pit vipers (Gloydius brevicaudus). Identified proteins were assigned to a few main toxin families. Disintegrin, phospholipase A2 (PLA2), serine proteinase, cysteine-rich secretory protein, C-type lectin-like protein, l-amino acid oxidase and snake venom metalloproteinase (SVMP) were detected in both venoms, while 5'-nucleotidase was detected only in the adult venom. SVMP was the predominant protein family in both venoms (neonate: 65.7%; adult: 64.4%), followed by PLA2 (neonate: 13.4%; adult: 25.0%). Antivenomic analysis revealed that commercial G. brevicaudus antivenom almost neutralized the chromatographic peaks with medium and high molecular masses in both venoms, but did not completely recognize peaks with low molecular mass. Toxicological and enzymatic activities show remarkable age-related variation in G. brevicaudus venom, probably resulting from variation in venom composition. Our data demonstrate age-related variation across venomics, antivenomics and biochemical profiles of G. brevicaudus venom, and have implications for the management of G. brevicaudus bites, including improving antivenom preparation by combining both venoms. This study investigates the composition and biochemical activity of neonate and adult Gloydius brevicaudus venoms. We found remarkable age-related variation in venom biological activity, likely the result of variation in venom composition. Antivenomics analysis was used to explore difference in neonate and adult G. brevicaudus venoms. Our findings have implications for the diagnosis and clinical management of G. brevicaudus bites, and the design of venom mixtures that will increase the efficacy of commercial antivenom. This article is part of a Special Issue entitled: Proteomics of non-model organisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Spectrum of human tails: A report of six cases

    Directory of Open Access Journals (Sweden)

    Biswanath Mukhopadhyay

    2012-01-01

    Full Text Available Human tail is a curiosity, a cosmetic stigma and presents as an appendage in the lumbosacral region. Six patients of tail in the lumbosacral region are presented here to discuss the spectrum of presentation of human tails. The embryology, pathology and treatment of this entity are discussed along with a brief review of the literature.

  11. Analytical Solution and Application for One-Dimensional Consolidation of Tailings Dam

    Directory of Open Access Journals (Sweden)

    Hai-ming Liu

    2018-01-01

    Full Text Available The pore water pressure of tailings dam has a very great influence on the stability of tailings dam. Based on the assumption of one-dimensional consolidation and small strain, the partial differential equation of pore water pressure is deduced. The obtained differential equation can be simplified based on the parameters which are constants. According to the characteristics of the tailings dam, the pore water pressure of the tailings dam can be divided into the slope dam segment, dry beach segment, and artificial lake segment. The pore water pressure is obtained through solving the partial differential equation by separation variable method. On this basis, the dissipation and accumulation of pore water pressure of the upstream tailings dam are analyzed. The example of typical tailings is introduced to elaborate the applicability of the analytic solution. What is more, the application of pore water pressure in tailings dam is discussed. The research results have important scientific and engineering application value for the stability of tailings dam.

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

    Science.gov (United States)

    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.

  13. Assessment of the risks of rats (Rattus norvegicus and opossums (Didelphis albiventris in different poultry-rearing areas in Argentina Avaliação dos riscos sanitários de ratos (Rattus norvegicus e gambás (Didelphis albiventris em diferentes granjas avícolas na Argentina

    Directory of Open Access Journals (Sweden)

    Isabel E. Gómez Villafañe

    2004-12-01

    Full Text Available We have studied the prevalence of Trichinella spiralis, Leptospira spp. and Salmonella spp. in rats and opossums that inhabit poultry farms of Exaltación de la Cruz, Buenos Aires, Argentina, to determine the potential sanitary risk for humans that are in contact with these animals. The study was carried out on 48 poultry farms between spring 1999 and winter 2001. The study of opossums began in winter 2000. During the study period we captured 152 Rattus norvegicus, 3 Rattus rattus, 16 Didelphis albiventris and 1 Lutreolina crassicaudata. We have registered the presence of rats and opossums in 70% and 27% of the studied farms, respectively. The percentage of farms with rats was independent of the presence or absence of pigs. We did not detect the presence of Leptospira spp. and Trichinella spiralis in any individual. We detected the presence of Salmonella Enteritidis in one Rattus norvegicus and one Didelphis albiventris. According to our results, the rats and opossums of poultry farms may not report a risk factor in the transmission of Trichinella and Leptospira under the present conditions; but the detection of Salmonella Enteritidis in rats as well as in opossums suggests the idea of applying prophylactics measurements on poultry farms.A prevalência de Trichinella spiralis, Leptospira spp. e Salmonella spp. foi estudada em ratos e gambás que habitam granjas avícolas da região de Exaltación de la Cruz, Buenos Aires, Argentina, com o objetivo de determinar o potencial risco sanitário para pessoas que ficam em contato com esses animais. O estudo foi realizado entre a primavera de 1999 e o inverno de 2001 em 48 granjas avícolas. O estudo em gambás iniciou-se no inverno de 2000. Foram capturados 152 Rattus norvegicus, 3 Rattus rattus, 16 Didelphis albiventris e 1 Lutreolina crassicaudata. Registrou-se a presença de ratos e de gambás em 70% e 27% das granjas estudadas, respectivamente. A percentagem de granjas com ratos foi independente da

  14. Leachability of radioactive constituents from uranium mine tailings

    International Nuclear Information System (INIS)

    Bryant, D.N.; Cohen, D.B.; Durham, R.W.

    1979-04-01

    A project was carried out using lysimeters to determine the leaching of radioactive constituents and BaRaSO 4 from abandoned uranium mine tailings. Lime addition to the surface of acidic abandoned tailings did not reduce the level of radioactive constituents in the leachate. Considerable increases in levels of the radionuclides 230 Th, 232 Th and 22 /8Th, as well as gross alpha and beta activity in the leachate, occurred five months after recycling of BaRaSO 4 sediments to the surface layers of abandoned tailings. After nine months of leaching, the levels of 226 Ra in the leachate were 30% greater than the tailings plus sediment treatment than from