Science.gov

Sample records for recruits co-inhabiting burrows

  1. Toxicity of microcystin-LR, a cyanobacterial toxin, to multiple life stages of the burrowing mayfly, Hexagenia, and possible implications for recruitment.

    PubMed

    Smith, Juliette L; Boyer, Gregory L; Mills, Edward; Schulz, Kimberly L

    2008-08-01

    Burrowing mayflies, genus Hexagenia, were extirpated from the major water bodies of North America in the early 1950s, paralleling an increase in eutrophication and organic pollution, and a decrease in dissolved oxygen concentrations. Burrowing mayflies recolonized the western basin of Lake Erie, but remain absent in other former habitats such as Oneida Lake, New York. Eutrophication is commonly associated with a shift in the phytoplankton community toward dominance by cyanobacteria, and therefore, one class of cyanobacterial toxins, microcystins, were investigated as a contributing factor to Hexagenia's eradication or as an impediment to recolonization. Laboratory experiments were conducted to determine if microcystin-LR (MC-LR) produced negative effects on Hexagenia at three points within its life cycle: egg, hatchling nymph (<24-h old, <1 mm total length), and pre-emergence nymph (>17 mm). Treatment concentrations ranged from the guideline set by the World Health Organization for drinking water (0.001 microg mL(-1)) to 0.1 microg mL(-1) for the egg experiment and 10 microg mL(-1) for the nymph trials. Eggs showed a delay in hatching and an altered distribution of hatching over the study period when submerged in 0.1 microg mL(-1) MC-LR (an elevated concentration representative of bloom scum). The 72-h (1.1 microg mL(-1)) and 96-h (0.049 microg mL(-1)) LC(50) values for hatchling nymphs exceeded typical bloom concentrations of North American lakes, (0.01 microg mL(-1)). Large nymphs were more tolerant of the toxin, as indicated by 100% survival over seven days exposure to 10 microg mL(-1), suggesting older larvae can withstand brief encounters with high microcystin levels for at least short periods of time. The sensitivity of young nymphs and eggs to MC-LR may have implications for the recruitment of the genus in water bodies with persistent summer cyanobacterial blooms. PMID:18246549

  2. Burrowing mechanics: burrow extension by crack propagation.

    PubMed

    Dorgan, Kelly M; Jumars, Peter A; Johnson, Bruce; Boudreau, B P; Landis, Eric

    2005-02-01

    Until now, the analysis of burrowing mechanics has neglected the mechanical properties of impeding, muddy, cohesive sediments, which behave like elastic solids. Here we show that burrowers can progress through such sediments by using a mechanically efficient, previously unsuspected mechanism--crack propagation--in which an alternating 'anchor' system of burrowing serves as a wedge to extend the crack-shaped burrow. The force required to propagate cracks through sediment in this way is relatively small: we find that the force exerted by the annelid worm Nereis virens in making and moving into such a burrow amounts to less than one-tenth of the force it needs to use against rigid aquarium walls. PMID:15690029

  3. Earliest evidence of cynodont burrowing.

    PubMed

    Damiani, Ross; Modesto, Sean; Yates, Adam; Neveling, Johann

    2003-08-22

    A 251 million year old partial burrow cast containing an articulated skeleton of the mammal-like carnivore Thrinaxodon liorhinus is the oldest evidence for burrowing by a cynodont synapsid. The burrow cast comes from terrestrial flood plain sediments close to the Permian-Triassic boundary in the Karoo of South Africa. Together with those of the later cynodont Trirachodon, the Thrinaxodon burrow cast indicates that burrow-making was broadly distributed in basal synapsids and has a long history in non-mammalian synapsid evolution. A reconstruction of its appendicular skeleton in cross-section indicates that Thrinaxodon was able to adopt a facultatively mammalian stance within its burrow shaft. Burrows of cynodont design are more common in Triassic rocks than previously realized, and suggest that burrowing may represent an adaptive response by cynodonts to the environmental conditions associated with the mass extinction event that punctuated the end of the preceding Permian period. The widespread occurrence of burrowing among extant mammals implies that the ancient synapsid ability to burrow conferred a strong adaptive value in the evolution of Mammalia. PMID:12965004

  4. Earliest evidence of cynodont burrowing.

    PubMed Central

    Damiani, Ross; Modesto, Sean; Yates, Adam; Neveling, Johann

    2003-01-01

    A 251 million year old partial burrow cast containing an articulated skeleton of the mammal-like carnivore Thrinaxodon liorhinus is the oldest evidence for burrowing by a cynodont synapsid. The burrow cast comes from terrestrial flood plain sediments close to the Permian-Triassic boundary in the Karoo of South Africa. Together with those of the later cynodont Trirachodon, the Thrinaxodon burrow cast indicates that burrow-making was broadly distributed in basal synapsids and has a long history in non-mammalian synapsid evolution. A reconstruction of its appendicular skeleton in cross-section indicates that Thrinaxodon was able to adopt a facultatively mammalian stance within its burrow shaft. Burrows of cynodont design are more common in Triassic rocks than previously realized, and suggest that burrowing may represent an adaptive response by cynodonts to the environmental conditions associated with the mass extinction event that punctuated the end of the preceding Permian period. The widespread occurrence of burrowing among extant mammals implies that the ancient synapsid ability to burrow conferred a strong adaptive value in the evolution of Mammalia. PMID:12965004

  5. Genetic characterization of the burrowing shrimp (Neotrypaea californiensis) in Washington and Oregon estuaries

    EPA Science Inventory

    The Ghost shrimp, (Neotrypaea californiensis) are burrowers, which have a wide demographic distribution along the United States Pacific Coast. Our study used genetic analysis to estimate the source populations of larvae recruiting into estuaries to allow a greater understanding ...

  6. Depth of artificial Burrowing Owl burrows affects thermal suitability and occupancy

    USGS Publications Warehouse

    Nadeau, Christopher P.; Conway, Courtney J.; Rathbun, Nathan

    2015-01-01

    Many organizations have installed artificial burrows to help bolster local Burrowing Owl (Athene cunicularia) populations. However, occupancy probability and reproductive success in artificial burrows varies within and among burrow installations. We evaluated the possibility that depth below ground might explain differences in occupancy probability and reproductive success by affecting the temperature of artificial burrows. We measured burrow temperatures from March to July 2010 in 27 artificial burrows in southern California that were buried 15–76 cm below the surface (measured between the surface and the top of the burrow chamber). Burrow depth was one of several characteristics that affected burrow temperature. Burrow temperature decreased by 0.03°C per cm of soil on top of the burrow. The percentage of time that artificial burrows provided a thermal refuge from above-ground temperature decreased with burrow depth and ranged between 50% and 58% among burrows. The percentage of time that burrow temperature was optimal for incubating females also decreased with burrow depth and ranged between 27% and 100% among burrows. However, the percentage of time that burrow temperature was optimal for unattended eggs increased with burrow depth and ranged between 11% and 95% among burrows. We found no effect of burrow depth on reproductive success across 21 nesting attempts. However, occupancy probability had a non-linear relationship with burrow depth. The shallowest burrows (15 cm) had a moderate probability of being occupied (0.46), burrows between 28 and 40 cm had the highest probability of being occupied (>0.80), and burrows >53 cm had the lowest probability of being occupied (<0.43). Burrowing Owls may prefer burrows at moderate depths because these burrows provide a thermal refuge from above-ground temperatures, and are often cool enough to allow females to leave eggs unattended before the onset of full-time incubation, but not too cool for incubating females that

  7. Burrow Occupancy Patterns of the Western Burrowing Owl in Southern Nevada

    SciTech Connect

    Paul D. Greger and Derek B. Hall

    2009-09-01

    Understanding long-term patterns of burrow occupancy for the Western Burrowing Owl (Athene cunicularia hypugaea) is necessary for the conservation of this species, especially in arid, desert ecosystems where burrow occupancy data are lacking. Monthly burrow monitoring was conducted over a 4-year period (1997–2001) in southern Nevada to determine burrow occupancy patterns of Burrowing Owls and to evaluate the effects of burrow type and desert region on burrow occupancy. Burrow occupancy occurred year-round and was most consistent in the Transition region and tended to be lowest in the Mojave Desert region. Peak burrow occupancy occurred during March through May, followed by a gradual decline in occupancy through the summer and fall until January and February, when occupancy was lowest. Occupancy was significantly higher at sites with both culvert and pipe burrows than at sites with earthen burrows in disturbed habitat or earthen burrows in natural habitat. Breeding-season occupancy was not significantly higher in wetter, cooler portions (e.g., Great Basin desert region) of the study area. Results suggest that occupancy is influenced by habitat features—such as suitable burrows in open areas with low vegetation—and climatic regime.

  8. Burrowing owl nesting productivity: A comparison between artificial and natural burrows on and off golf courses

    USGS Publications Warehouse

    Smith, M.D.; Conway, C.J.; Ellis, L.A.

    2005-01-01

    Burrowing owl (Athene cunicularia) populations are declining in many portions of their range, and lack of suitable nesting burrows is thought to be one reason for observed declines. Burrowing owls are attracted to golf courses because the birds generally nest and forage in short-grass, open areas, yet golf courses seldom have suitable nesting burrows. We examined the efficacy of installing artificial nesting burrows on golf courses as a way to help restore local burrowing owl populations. From 2001-2004 we monitored over 175 natural burrows off golf courses, 14 natural burrows on golf courses, 86 artificial burrows off golf courses, and 130 artificial burrows on golf courses. Owls located and used 8 of the 130 artificial burrows installed on golf courses (4 were used as nests). Owls selected burrows that were closer to existing natural burrows, farther from maintained areas (areas receiving turf maintenance by golf course staff), and farther from sprinkler heads. All 4 of the artificial burrows used as nests successfully fledged young, and annual site fidelity for owls nesting on golf courses was higher than for owls nesting off golf courses. However, annual fecundity of owls nesting on golf courses was lower than that of owls nesting off golf courses. If golf courses have sufficiently large nonmaintained areas and there are nesting owls nearby, course managers potentially can help in restoring local burrowing owl populations by installing artificial nesting burrows on the periphery of the course. However, the low fecundity on golf courses reported here should be more thoroughly examined before artificial burrows are used to attract owls to golf courses.

  9. Rugged Video System For Inspecting Animal Burrows

    NASA Technical Reports Server (NTRS)

    Triandafils, Dick; Maples, Art; Breininger, Dave

    1992-01-01

    Video system designed for examining interiors of burrows of gopher tortoises, 5 in. (13 cm) in diameter or greater, to depth of 18 ft. (about 5.5 m), includes video camera, video cassette recorder (VCR), television monitor, control unit, and power supply, all carried in backpack. Polyvinyl chloride (PVC) poles used to maneuver camera into (and out of) burrows, stiff enough to push camera into burrow, but flexible enough to bend around curves. Adult tortoises and other burrow inhabitants observable, young tortoises and such small animals as mice obscured by sand or debris.

  10. The biomechanics of burrowing and boring.

    PubMed

    Dorgan, Kelly M

    2015-01-15

    Burrowers and borers are ecosystem engineers that alter their physical environments through bioturbation, bioirrigation and bioerosion. The mechanisms of moving through solid substrata by burrowing or boring depend on the mechanical properties of the medium and the size and morphology of the organism. For burrowing animals, mud differs mechanically from sand; in mud, sediment grains are suspended in an organic matrix that fails by fracture. Macrofauna extend burrows through this elastic mud by fracture. Sand is granular and non-cohesive, enabling grains to more easily move relative to each other, and macrofaunal burrowers use fluidization or plastic rearrangement of grains. In both sand and mud, peristaltic movements apply normal forces and reduce shear. Excavation and localized grain compaction are mechanisms that plastically deform sediments and are effective in both mud and sand, with bulk excavation being used by larger organisms and localized compaction by smaller organisms. Mechanical boring of hard substrata is an extreme form of excavation in which no compaction of burrow walls occurs and grains are abraded with rigid, hard structures. Chemical boring involves secretion to dissolve or soften generally carbonate substrata. Despite substantial differences in the mechanics of the media, similar burrowing behaviors are effective in mud and sand. PMID:25609781

  11. Localized fluidization burrowing mechanics of Ensis directus.

    PubMed

    Winter, Amos G; Deits, Robin L H; Hosoi, A E

    2012-06-15

    Muscle measurements of Ensis directus, the Atlantic razor clam, indicate that the organism only has sufficient strength to burrow a few centimeters into the soil, yet razor clams burrow to over 70 cm. In this paper, we show that the animal uses the motions of its valves to locally fluidize the surrounding soil and reduce burrowing drag. Substrate deformations were measured using particle image velocimetry (PIV) in a novel visualization system that enabled us to see through the soil and watch E. directus burrow in situ. PIV data, supported by soil and fluid mechanics theory, show that contraction of the valves of E. directus locally fluidizes the surrounding soil. Particle and fluid mixtures can be modeled as a Newtonian fluid with an effective viscosity based on the local void fraction. Using these models, we demonstrate that E. directus is strong enough to reach full burrow depth in fluidized soil, but not in static soil. Furthermore, we show that the method of localized fluidization reduces the amount of energy required to reach burrow depth by an order of magnitude compared with penetrating static soil, and leads to a burrowing energy that scales linearly with depth rather than with depth squared. PMID:22623195

  12. Burrowing Owls, Pulex irritans, and Plague.

    PubMed

    Belthoff, James R; Bernhardt, Scott A; Ball, Christopher L; Gregg, Michael; Johnson, David H; Ketterling, Rachel; Price, Emily; Tinker, Juliette K

    2015-09-01

    Western Burrowing Owls (Athene cunicularia hypugaea) are small, ground-dwelling owls of western North America that frequent prairie dog (Cynomys spp.) towns and other grasslands. Because they rely on rodent prey and occupy burrows once or concurrently inhabited by fossorial mammals, the owls often harbor fleas. We examined the potential role of fleas found on burrowing owls in plague dynamics by evaluating prevalence of Yersinia pestis in fleas collected from burrowing owls and in owl blood. During 2012-2013, fleas and blood were collected from burrowing owls in portions of five states with endemic plague-Idaho, Oregon, Washington, Colorado, and South Dakota. Fleas were enumerated, taxonomically identified, pooled by nest, and assayed for Y. pestis using culturing and molecular (PCR) approaches. Owl blood underwent serological analysis for plague antibodies and nested PCR for detection of Y. pestis. Of more than 4750 fleas collected from owls, Pulex irritans, a known plague vector in portions of its range, comprised more than 99.4%. However, diagnostic tests for Y. pestis of flea pools (culturing and PCR) and owl blood (PCR and serology) were negative. Thus, even though fleas were prevalent on burrowing owls and the potential for a relationship with burrowing owls as a phoretic host of infected fleas exists, we found no evidence of Y. pestis in sampled fleas or in owls that harbored them. We suggest that studies similar to those reported here during plague epizootics will be especially useful for confirming these results. PMID:26367482

  13. Using Animal Burrows to Integrate Math and Biology

    ERIC Educational Resources Information Center

    Crowe, Mary; Boston, Kellie

    2004-01-01

    In this activity students examine burrow casts to learn about burrowing animals and practice their math skills. Students compute the volume and average circumference of a burrow. They also determine whether a relationship exists between burrow volume and the size of the organism that created it. Students use science as inquiry as they analyze and…

  14. Burrowing inhibition by fine textured beach fill: Implications for recovery of beach ecosystems

    NASA Astrophysics Data System (ADS)

    Viola, Sloane M.; Hubbard, David M.; Dugan, Jenifer E.; Schooler, Nicholas K.

    2014-10-01

    Beach nourishment is often considered the most environmentally sound method of maintaining eroding shorelines. However, the ecological consequences are poorly understood. Fill activities cause intense disturbance and high mortality and have the potential to alter the diversity, abundance, and distribution of intertidal macroinvertebrates for months to years. Ecological recovery following fill activities depends on successful recolonization and recruitment of the entire sandy intertidal community. The use of incompatible sediments as fill material can strongly affect ecosystem recovery. We hypothesized that burrowing inhibition of intertidal animals by incompatible fine fill sediments contributes to ecological impacts and limits recovery in beach ecosystems. We experimentally investigated the influence of intertidal zone and burrowing mode on responses of beach invertebrates to altered sediment texture (28-38% fines), and ultimately the potential for colonization and recovery of beaches disturbed by beach filling. Using experimental trials in fill material and natural beach sand, we found that the mismatched fine fill sediments significantly inhibited burrowing of characteristic species from all intertidal zones, including sand crabs, clams, polychaetes, isopods, and talitrid amphipods. Burrowing performance of all five species we tested was consistently reduced in the fill material and burrowing was completely inhibited for several species. The threshold for burrowing inhibition by fine sediment content in middle and lower beach macroinvertebrates varied by species, with highest sensitivity for the polychaete (4% fines, below the USA regulatory limit of 10% fines), followed by sand crabs and clams (20% fines). These results suggest broader investigation of thresholds for burrowing inhibition in fine fill material is needed for beach animals. Burrowing inhibition caused by mismatched fill sediments exposes beach macroinvertebrates to stresses, which could depress

  15. Application of morphologic burrow architects: lungfish or crayfish?

    USGS Publications Warehouse

    Hasiotis, Stephen T.; Mitchell, Charles E.; Dubiel, Russell R.

    1993-01-01

    A methodology for trace fossil identification using burrowing signatures is tested by evaluating ancient and modern lungfish and crayfish burrows and comparing them to previously undescribed burrows in a stratigraphic interval thought to contain both lungfish and crayfish burrows. Permian burrows that bear skeletal remains of the lungfish Gnathorhiza, from museum collections, were evaluated to identify unique burrow morphologies that could be used to distinguish lungfish from crayfish burrows when fossil remains are absent. The lungfish burrows were evaluated for details of the burrowing mechanism preserved in the burrow morphologies together forming burrowing signatures and were compared to new burrows in the Chinle Formation of western Colorado to test the methodology of using burrow signatures to identify unknown burrows. Permian lungfish aestivation burrows show simple, nearly vertical, unbranched architectures and relatively smooth surficial morphologies with characteristic quasi‐horizontal striae on the burrow walls and vertical striae on the bulbous terminus. Burrow lengths do not exceed 0.5 m. In contrast, modern and ancient crayfish burrows exhibit simple to highly complex architectures with highly textured surficial morphologies. Burrow lengths may reach 4 to 5 m. Burrow morphologies unlike those identified in Gnathorhiza aestivation burrows were found in four burrow groups from museum collections. Two of these groups exhibit simple architectures and horizontal striae that were greater in sinuosity and magnitude, respectively. One of these burrows contains the remains of Lysorophus, but the burrow surface reveals no reliable surficial characteristics. It is not clear whether Lysorophus truly burrowed or merely occupied a pre‐existing structure. The other two groups exhibit surficial morphologies similar to those found on modern and ancient crayfish burrows and may provide evidence of freshwater crayfish in the Permian. Burrows from the Upper Triassic

  16. Burrow extension with a proboscis: mechanics of burrowing by the glycerid Hemipodus simplex.

    PubMed

    Murphy, Elizabeth A K; Dorgan, Kelly M

    2011-03-15

    Burrowing marine infauna are morphologically diverse and ecologically important as ecosystem engineers. The polychaetes Nereis virens and Cirriformia moorei extend their burrows by crack propagation. Nereis virens does so by everting its pharynx and C. moorei, lacking an eversible pharynx or proboscis, uses its hydrostatic skeleton to expand its anterior. Both behaviors apply stress to the burrow wall that is amplified at the tip of the crack, which extends by fracture. That two species with such distinct morphologies and life histories both burrow by fracturing sediment suggests that this mechanism may be widespread among burrowers. We tested this hypothesis with the glycerid polychaete Hemipodus simplex, which has an eversible proboscis that is much longer and everts more rapidly than the pharynx of N. virens. When the proboscis is fully everted, the tip flares out wider than the rest of the proboscis, creating a shape and applying a stress distribution similar to that of N. virens and resulting in relatively large forces near the tip of the crack. These forces are larger than necessary to extend the crack by fracture and are surprisingly uncorrelated with the resulting stress amplification at the crack tip, which is also larger than necessary to extend the burrow by fracture. These large forces may plastically deform the mud, allowing the worm to build a semi-permanent burrow. Our results illustrate that similar mechanisms of burrowing are used by morphologically different burrowers. PMID:21346130

  17. The burrowing origin of modern snakes

    PubMed Central

    Yi, Hongyu; Norell, Mark A.

    2015-01-01

    Modern snakes probably originated as habitat specialists, but it controversial unclear whether they were ancestrally terrestrial burrowers or marine swimmers. We used x-ray virtual models of the inner ear to predict the habit of Dinilysia patagonica, a stem snake closely related to the origin of modern snakes. Previous work has shown that modern snakes perceive substrate vibrations via their inner ear. Our data show that D. patagonica and modern burrowing squamates share a unique spherical vestibule in the inner ear, as compared with swimmers and habitat generalists. We built predictive models for snake habit based on their vestibular shape, which estimated D. patagonica and the hypothetical ancestor of crown snakes as burrowers with high probabilities. This study provides an extensive comparative data set to test fossoriality quantitatively in stem snakes, and it shows that burrowing was predominant in the lineages leading to modern crown snakes. PMID:26702436

  18. The zoogeomorphic characteristics of burrows and burrowing by nine-banded armadillos (Dasypus novemcinctus)

    NASA Astrophysics Data System (ADS)

    Sawyer, Carol F.; Brinkman, Donald C.; Walker, Vincent D.; Covington, Tyler D.; Stienstraw, Elizabeth A.

    2012-07-01

    Burrowing animals act like a geomorphic disturbance, changing the environment through soil excavation, landform creation and bioturbation. The potential zoogeomorphic effects of these actions include modification of surficial features, increased soil erosion, changes in the growth and distribution of vegetation, and modifications to soil fertility. The burrowing ninebanded armadillo (Dasypus novemcinctus) migrated to North America prior to the 1850s and has since continued to expand its habitat to the American Southeast and parts of the Midwest. Little data are available on the zoogeomorphic impact of the burrowing nature of this species, making it difficult to predict future implications of this animal as it continues to migrate into new regions. On the University of South Alabama campus, in Mobile, Alabama, armadillos are present on a 35-hectare unprotected forested preserve used by the university community for outdoor activities and research. To understand the potential zoogeomorphic impact of armadillo burrows on the local environment, morphometric measurements were recorded on 187 burrows located in the study area. Using dimensions of burrow entrances and minimum lengths of tunnels in calculations, armadillos excavated approximately 0.029 m3 to 0.04 m3 of soil from each burrow. The entrances to burrows averaged 33.5° in slope and tended to be located in a microhabitat of a fallen tree, exposed tree roots, or a sideslope. Persistent fall of forest litter and anthropogenic modifications makes positive identification of spoil mounds possible in approximately half of the burrow sites. Surface modification by armadillos is ongoing in the study area with over half of the burrows classified as active during the four-month project. We concluded that, for southern Alabama, armadillos prefer to excavate burrows into sideslopes, and that given the lack of ground cover, sandy soil, and humid climate, armadillos are an important zoogeomorphic agent in the region.

  19. Dominant infaunal communities at risk in shoreline habitats: Burrowing Thalassinid Crustacea. Final report

    SciTech Connect

    Felder, D.L.; Griffis, R.B.

    1994-04-01

    Oil contamination and physical perturbation of intertidal and shallow subtidal substrates threaten mass mortalities of ghost shrimp (Lepidophthalmus and Callichirus) that occur in extensive populations in coastal habitats of the northern Gulf of Mexico. These species may play important ecological roles in determining coastal habitat quality and reductions in densities may substantially alter the physical, chemical, and biological characteristics of benthic habitats. In the Gulf of Mexico, ghost shrimp burrows form traps for entrainment of oil into sediments and beachfront oil accumulations may result in mass mortalities. This study documents the population biology and ecological role of ghost shrimp in beachfront and bay habitats of the northern Gulf of Mexico. Seasonal variation in breeding, recruitment, growth, abundance and biomass is presented for two species. Restoration of diminished populations occurs through planktonic recruitment and relocation of burrowed postlarvae. Populations increase the sediment-water interface by adding 1-2 sq m of burrow wall beneath each sq m sediment surface, and increase the flux of nutrients from sediments to the water column by pumping nutrient-rich water from burrows.

  20. Burrowing energetics of the Giant Burrowing Cockroach Macropanesthia rhinoceros: an allometric study.

    PubMed

    Xu, Liangwen; Snelling, Edward P; Seymour, Roger S

    2014-11-01

    Burrowing is an important life strategy for many insects, yet the energetic cost of constructing burrows has never been studied in insects of different sizes. Open flow respirometry was used to determine the allometric scaling of standard metabolic rate (MRS) and burrowing metabolic rate (MRB) in the heaviest extant cockroach species, the Giant Burrowing Cockroach Macropanesthia rhinoceros, at different stages of development. At 10 °C, MRS (mW) scales with body mass (M; g) according to the allometric power equation, MRS=0.158M(0.74), at 20 °C the equation is MRS=0.470M(0.53), and at 30 °C the equation is MRS=1.22M(0.49) (overall Q10=2.23). MRS is much lower in M. rhinoceros compared to other insect species, which is consistent with several aspects of their life history, including flightlessness, extreme longevity (>5 years), burrowing, parental behaviour, and an energy-poor diet (dry eucalypt leaf litter). Energy expenditure during burrowing at 25 °C scales according to MRB=16.9M(0.44), and is approximately 17 times higher than resting rates measured at the same temperature, although the metabolic cost over a lifetime is probably low, because the animal does not burrow to find food. The net cost of transport by burrowing (Jm(-1)) scales according to NCOT=120M(0.49), and reflects the energetically demanding task of burrowing compared to other forms of locomotion. The net cost of excavating the soil (J cm(-3)) is statistically independent of body size. PMID:25257537

  1. Gopherus agassizii (desert tortoise). Burrow collapse

    USGS Publications Warehouse

    Loughran, Caleb L.; Ennen, Joshua; Lovich, Jeffrey E.

    2011-01-01

    In the deserts of the southwestern U.S., burrows are utilized by the Desert Tortoise to escape environmental extremes (reviewed by Ernst and Lovich 2009. Turtles of the United States and Canada. 2nd ed. Johns Hopkins Univ. Press, Baltimore, Maryland. 827 pp.). However, the potential for mortality through burrow collapse and entrapment is poorly documented. Nicholson and Humphreys (1981. Proceedings of the Desert Tortoise Council, pp. 163−194) suggested that collapse due to livestock trampling may cause mortality. In addition, Lovich et al. (2011. Chelon. Cons. Biol. 10[1]:124–129) documented a Desert Tortoise that used a steel culvert as a burrow surrogate. The culvert filled completely with sediment following a significant rain event, entombing the animal and ultimately resulting in its death. We note that this mortality was associated with an anthropogenic structure; because tortoises are prodigious diggers, one might hypothesize that they have the ability to dig out of collapsed natural burrows in most situations. Circumstances described here presented us with an opportunity to test this hypothesis.

  2. Design of a Localized Fluidization Burrowing Robot

    NASA Astrophysics Data System (ADS)

    Dorsch, Daniel; Winter, Amos

    2014-11-01

    This presentation will focus on the critical fluid and granular mechanics principles that drove the design of RoboClam 2.0, a self-actuated, radially expanding underwater burrowing device. RoboClam 2.0 was inspired by the Atlantic razor clam, Ensis directus, which burrows by contracting its valves and fluidizing the surrounding soil to reduce burrowing drag. This contraction results in a localized fluidized region occurring 1-5 body radii away from the animal. Moving through a fluidized, rather than static, soil requires energy that scales linearly with depth, rather than depth squared. In addition to providing an advantage for the animal, localized fluidization may yield significant value to engineering applications such as subsea robot anchoring and pipe installation. RoboClam 2.0 is sized to be an anchoring platform for autonomous underwater vehicles. We will present the scaling relationships that can be used to design RoboClam derivatives for different size scales and applications. The critical speed, displacement and force with which the device must contract to create fluidization are calculated based on soil parameters. These parametric relationships allow for choosing actuators of appropriate size and power output for desired burrowing performance.

  3. A Microstructural View of Burrowing with Roboclam

    NASA Astrophysics Data System (ADS)

    Nordstrom, Kerstin; Dorsch, Dan; Losert, Wolfgang; Winter, V., Amos

    2014-03-01

    Roboclam is a burrowing technology inspired by Ensis directus, the Atlantic razor clam. The organism only has sufficient strength to burrow a few centimeters into the soil, yet razor clams dig to over 70 cm. The animal uses motions of its valves to contract and thereby locally fluidize the surrounding soil and reduce burrowing drag. Roboclam technology is valuable for subsea applications that could benefit from efficient burrowing, such as anchoring, mine detonation, and cable laying. We directly visualize the movement of soil grains during the contraction of Roboclam, using a novel index-matching technique along with particle tracking. We show that a previously developed mechanical theory for E. directus describes the size of the failure zone around contracting Roboclam, provided that the timescale of contraction is sufficiently large. We also show that the nonaffine motions of the grains are a small fraction of the motion within the fluidized zone, affirming the relevance of a continuum model for this system, even though the grain size is comparable to the size of Roboclam.

  4. Burrows of the sagebrush vole (Lemmiscus curtatus) in southeastern Idaho

    SciTech Connect

    Mullican, T.R.; Keller, B.L.

    1987-04-30

    Burrows of the sagebrush vole (Lemmiscus curtatus) were analyzed by injecting them with expanding polyurethane foam. Average mean depth +/- 1 SE of four burrows was 12.5 +/- 2.6 cm. Tunnels were wider than high and flat on the bottom. Three of four burrows were nearly linear, with an average of five entrances. Burrows usually contained one nest made of Artemisia tridentat bark. No middens or communal nests were found. The burrow structure in sagebrush habitat suggests that sagebrush voles occur singly or in pairs rather than in colonies.

  5. Chemical induction in mangrove crab megalopae, Ucides cordatus (Ucididae): Do young recruits emit metamorphosis-triggering odours as do conspecific adults?

    NASA Astrophysics Data System (ADS)

    Simith, Darlan de Jesus de Brito; Abrunhosa, Fernando Araújo; Diele, Karen

    2013-10-01

    In many brachyuran species, including the mangrove crab Ucides cordatus, water-soluble chemicals (odours) emitted by adult residents trigger metamorphosis of megalopae, probably facilitating habitat selection and settlement near conspecific crab population. New field findings revealed that early benthic crab stages co-inhabit burrows of both juveniles and adults of U. cordatus which raised the question whether megalopae are also stimulated by sexually immature juveniles. Therefore, we tested in an experimental laboratory study the hypothesis that small benthic recruits and older juveniles also emit metamorphosis-stimulating odours as do conspecific adult crabs. U. cordatus megalopae were cultivated in eight conspecific odour-treatments containing seawater previously conditioned with crabs of different carapace widths (CW 0.15-5.0 cm) and in a control treatment with filtered seawater not conditioned with crabs. In all odour-treatments, including those with small immature crabs, the percentage of metamorphosed larvae was significantly higher (≥74%) and the average development was shorter (15.8-19.3 days) than in the control group, where only 30% moulted after 25.6 ± 6.6 days of megalopal development. In addition, megalopae developed 2.7 days faster when exposed to odours from young and older juveniles compared to those larvae kept in contact with odours from conspecific adults. Our results clearly demonstrate that the emission of metamorphic odours in U. cordatus is independent of size/age or sexual maturity. The responsiveness of megalopae to chemicals emitted by resident crabs of varying ages should aid the natural recovery of U. cordatus populations in areas significantly affected by size-selective fishery where only large conspecific adults are harvested.

  6. Population trajectory of burrowing owls (Athene cunicularia) in eastern Washington

    USGS Publications Warehouse

    Conway, C.J.; Pardieck, K.L.

    2006-01-01

    Anecdotal evidence suggests that burrowing owls have declined in Washington. The Washington Department of Fish and Wildlife is currently conducting a status review for burrowing owls which will help determine whether they should be listed as threatened or endangered in the state. To provide insights into the current status of burrowing owls (Athene cunicularia), we analyzed data from the North American Breeding Bird Survey using two analytical approaches to determine their current population trajectory in eastern Washington. We used a one-sample t-test to examine whether trend estimates across all BBS routes in Washington differed from zero. We also used a mixed model analysis to estimate the rate of decline in number of burrowing owls detected between 1968 and 2005. The slope in number of burrowing owls detected was negative for 12 of the 16 BBS routes in Washington that have detected burrowing owls. Numbers of breeding burrowing owls detected in eastern Washington declined at a rate of 1.5% annually. We suggest that all BBS routes that have detected burrowing owls in past years in eastern Washington be surveyed annually and additional surveys conducted to track population trends of burrowing owls at finer spatial scales in eastern Washington. In the meantime, land management and regulatory agencies should ensure that publicly managed areas with breeding burrowing owls are not degraded and should implement education and outreach programs to promote protection of privately owned areas with breeding owls.

  7. Does thermal convection occur in mammalian burrows during the night?

    NASA Astrophysics Data System (ADS)

    Ganot, Y.; Weisbrod, N.; Dragila, M. I.; Nachshon, U.

    2010-12-01

    Burrowing is a common habit of mammals in arid zones, yet knowledge of environmental conditions within animal burrows, and especially of the way burrows are ventilated, is scarce. The ventilation rate of a burrow controls air composition within the burrow by driving gas exchange between the lower part of the burrow where the animal typically lives, and the atmosphere. Ventilation can be achieved by the following mechanisms: (1) diffusion; (2) external winds; (3) movement of the inhabitant within the burrow (the 'piston-effect'); and (4) natural thermal convection, a process by which a natural thermal gradient between burrow and atmosphere creates a density gradient which induces air flow. Here we investigate the role of thermal convection in burrow ventilation. For this purpose, artificial burrows (65 cm in depth and 7 cm in diameter) were drilled in loess soil in the Negev Desert of Israel and a network of thermocouples was installed to continuously monitor and record temperature distribution within these burrows. The results show that free convection occurs on a daily basis during the night and early morning. During these times, burrow air temperature was warmer than atmospheric air, and temperature readings pointed to the regular occurrence of convection flow in a thermosyphon pattern. Volume fluxes were calculated based on analytical solution and empirical correlations. For the artificial burrows investigated, an average CO2 volume flux of about 15 liter/hour was calculated during the night when convective conditions prevailed. For comparison, CO2 volume flux by steady-state diffusion alone is 3 orders of magnitude lower.

  8. The Mechanics of Localized Fluidization Burrowing

    NASA Astrophysics Data System (ADS)

    Winter, Amos

    2013-11-01

    This presentation will focus on the granular mechanics and critical timescales related to localized fluidization burrowing, a digging method inspired by the Atlantic razor clam (Ensis directus). The animal uses motions of its valves to locally fail and then fluidize surrounding soil to reduce burrowing energy and drag. The characteristic contraction time to achieve fluidization can be determined from substrate properties. The geometry of the fluidized zone is dictated by the coefficient of lateral earth pressure and friction angle of the soil. Calculations using full ranges for these parameters indicate that the fluidized zone is a local effect, occurring between 1-5 body radii away from the animal. The energy associated with motion through fluidized substrate - characterized by a depth-independent density and viscosity - scales linearly with depth. In contrast, moving through static soil requires energy that scales with depth squared. For engineers, localized fluidization offers a mechanically simple and purely kinematic method to dramatically reduce energy costs associated with digging. This concept is demonstrated with RoboClam, an E. directus-inspired robot. Using a genetic algorithm to find optimal digging kinematics, RoboClam has achieved localized fluidization burrowing performance comparable to that of the animal, with a linear energy-depth relationship, in both idealized granular glass beads and E. directus' native cohesive mudflat habitat.

  9. Burrowing Owl Monitoring Report for Calendar Year 2012

    SciTech Connect

    Wilde, Justin W.; Lindsey, Cole T.; Nugent, John J.

    2013-03-14

    The monitoring during 2012 focused on documenting the status of known burrows. Newly identified burrows were documented while examining historical locations, during ecological resource reviews, or discovered during other monitoring efforts. The timing of the monitoring effort allowed staff to perform the surveys without disrupting any breeding or hatching, while also allowing for easy discernment of adults from juveniles, which helped in determining burrow-use type.

  10. Oxygen penetration through invertebrate burrow walls in Korean tidal flat

    NASA Astrophysics Data System (ADS)

    Koo, Bon Joo; Koh, Chul-Hwan

    2013-12-01

    Macrofaunal burrows increase the surface area of the sediment-water interface, which has a great impact on the metabolism of aerobic microbes and the oscillation of reduced metabolites within the sediment. Given the importance of macrofauna in surficial sediments, the aim of this study is to examine the effects of burrow architectures on dissolved oxygen diffusion rates in comparison with unburrowed sediment, and thereby to evaluate the theoretical assumption used for modeling solute distribution in the burrow system using field samples. Employing microsensors, horizontal oxygen profiles were measured on a micrometer scale around burrows of seven invertebrates in tidal flats of the west coast of Korea. Oxygen diffusion distance through the burrow walls of seven invertebrates showed spatio-temporal variation with a range of 0.6 to 2.9 mm. Two groups of burrows were identified based on their oxygen diffusive properties relative to unburrowed sediments: 1) oxygen penetration similar to that of ambient sediments and 2) clearly enhanced oxygen penetration. Differences in the diffusive properties of the burrow wall were related to the burrow depth and diameter, existence of mucus lining on the wall, sediment grain size, and tidal phases. Also inhabitant activity was an important factor affecting oxygen penetration, which is discussed in the paper. These results further demonstrate that simplified assumptions (i.e. burrow structures are viewed as direct biogeochemical extensions of the sediment-water interface) may not be exact representation of the nature.

  11. Meandering worms: mechanics of undulatory burrowing in muds.

    PubMed

    Dorgan, Kelly M; Law, Chris J; Rouse, Greg W

    2013-04-22

    Recent work has shown that muddy sediments are elastic solids through which animals extend burrows by fracture, whereas non-cohesive granular sands fluidize around some burrowers. These different mechanical responses are reflected in the morphologies and behaviours of their respective inhabitants. However, Armandia brevis, a mud-burrowing opheliid polychaete, lacks an expansible anterior consistent with fracturing mud, and instead uses undulatory movements similar to those of sandfish lizards that fluidize desert sands. Here, we show that A. brevis neither fractures nor fluidizes sediments, but instead uses a third mechanism, plastically rearranging sediment grains to create a burrow. The curvature of the undulating body fits meander geometry used to describe rivers, and changes in curvature driven by muscle contraction are similar for swimming and burrowing worms, indicating that the same gait is used in both sediments and water. Large calculated friction forces for undulatory burrowers suggest that sediment mechanics affect undulatory and peristaltic burrowers differently; undulatory burrowing may be more effective for small worms that live in sediments not compacted or cohesive enough to extend burrows by fracture. PMID:23446526

  12. Meandering worms: mechanics of undulatory burrowing in muds

    PubMed Central

    Dorgan, Kelly M.; Law, Chris J.; Rouse, Greg W.

    2013-01-01

    Recent work has shown that muddy sediments are elastic solids through which animals extend burrows by fracture, whereas non-cohesive granular sands fluidize around some burrowers. These different mechanical responses are reflected in the morphologies and behaviours of their respective inhabitants. However, Armandia brevis, a mud-burrowing opheliid polychaete, lacks an expansible anterior consistent with fracturing mud, and instead uses undulatory movements similar to those of sandfish lizards that fluidize desert sands. Here, we show that A. brevis neither fractures nor fluidizes sediments, but instead uses a third mechanism, plastically rearranging sediment grains to create a burrow. The curvature of the undulating body fits meander geometry used to describe rivers, and changes in curvature driven by muscle contraction are similar for swimming and burrowing worms, indicating that the same gait is used in both sediments and water. Large calculated friction forces for undulatory burrowers suggest that sediment mechanics affect undulatory and peristaltic burrowers differently; undulatory burrowing may be more effective for small worms that live in sediments not compacted or cohesive enough to extend burrows by fracture. PMID:23446526

  13. [A preliminary study on burrow ecology of Manis pentadactyla].

    PubMed

    Wu, Shibao; Ma, Guangzhi; Chen, Hai; Xu, Zhaorong; Li, Youyu; Liu, Naifa

    2004-03-01

    A total of 61 pangolin(Manis pentadactyla) burrows at Dawuling Natural Reserve were recorded and measured from June 2000 to May 2001, and 40 of them were dissected. The results indicated that all the burrows were blind without branch. The long diameter of entrance was 14.20 +/- 2.79 cm(n = 61), and the short one was 12.50 +/- 2.83 cm(n = 61). These burrows could be divided into two types, i.e., winter burrows and summer burrows. Winter burrows were relatively deeper(1.44 +/- 0.73 m, n = 28), and summer burrows were relatively shallower (0.32 +/- 0.11 m, n = 12). The soil in burrows was usually soft, damp and thick, with a thick surface layer of organic matter. The main motive of digging burrows was to prey on termites, hibernate, rest, breed, hide, and defense. The mean residing duration of pangolin in a burrow was 12.25 +/- 2.25 d. Pangolin rarely utilized the used burrows, and the reutilization rate of used burrows was only 8.33%. The surroundings factors of 61 burrows were recorded, and divided into 9 categories and 27 subcategories. According to the occurrence frequency of each factor and the cluster analysis results of 61 burrows, the habitat selection of pangolin was discussed, which showed that pangolin preferred creating burrows at the sites with weak human disturbance (distance from disturbance source beyond 1,000 m), steep slope(30 degrees-60 degrees), half sunny and half shady slope, mixed coniferous and broadleaf forest, moderate elevation(760-1,500 m), good hiding conditions at entrance(full cover or partial cover), middle or lower slope location, and easily accessing to water source(distance from water source within 500 m). Pangolin was averse to establish burrows at the habitats with shady slope, poor hiding condition at entrance(bare), sharp steeper(> 60 degrees) or gentle (< 30) slope, higher elevation (over 1,500 m), and coniferous forest. Pangolin preferred south facing, and strongly avoided north facing entrance. PMID:15227988

  14. Burrowing activities of the larval lamprey

    USGS Publications Warehouse

    Sawyer, Philip J.

    1959-01-01

    Since the appearance in 1950 of Applegate's work on the sea lamprey in Michigan (U. S. Fish and Wildl. Serv., Spec. Sci. Rept.; Fish, No. 55) and the subsequent development of means to control lampreys in the Great Lakes, biologists have accumulated much additional information on adult lampreys. Larval lampreys, however, are difficult animals to observe in the field, and many facets of their behavior are still unknown. While working with the U. S. Fish and Wildlife Service, I kept ammocetes in captivity, and was able to observe their burrowing activities.

  15. Energetics of burrowing by the cirratulid polychaete Cirriformia moorei.

    PubMed

    Dorgan, Kelly M; Lefebvre, Stephane; Stillman, Jonathon H; Koehl, M A R

    2011-07-01

    Burrowing through marine sediments has been considered to be much more energetically expensive than other forms of locomotion, but previous studies were based solely on external work calculations and lacked an understanding of the mechanical responses of sediments to forces applied by burrowers. Muddy sediments are elastic solids through which worms extend crack-shaped burrows by fracture. Here we present data on energetics of burrowing by Cirriformia moorei. We calculated the external energy per distance traveled from the sum of the work to extend the burrow by fracture and the elastic work done to displace sediment as a worm moves into the newly formed burrow to be 9.7 J kg(-1) m(-1) in gelatin and 64 J kg(-1) m(-1) in sediment, much higher than for running or walking. However, because burrowing worms travel at slow speeds, the increase in metabolic rate due to burrowing is predicted to be small. We tested this prediction by measuring aerobic metabolism (oxygen consumption rates) and anaerobic metabolism (concentrations of the anaerobic metabolite tauropine and the energy-storage molecule phosphocreatine) of C. moorei. None of these components was significantly different between burrowing and resting worms, and the low increases in oxygen consumption rates or tauropine concentrations predicted from external work calculations were within the variability observed across individuals. This result suggests that the energy to burrow, which could come from aerobic or anaerobic sources, is not a substantial component of the total metabolic energy of a worm. Burrowing incurs a low cost per unit of time. PMID:21653814

  16. IMPACT OF BURROWING SHRIMP POPULATIONS ON C, N CYCLING AND WATER QUALITY IN WESTERN NORTH AMERICAN TEMPERATE ESTUARIES

    EPA Science Inventory

    Thalassinid burrowing shrimp (predominantly, Neotrypaea californiensis and Upogebia pugettensis) inhabit large expanses of tide flats in North American Pacific estuaries, from British Columbia to Baja California. Feeding, burrowing, and burrow irrigation by burrowing shrimp can ...

  17. IMPACT OF BURROWING SHRIMP POPULATIONS ON NITROGEN CYCLING AND WATER QUALITY IN WESTERN NORTH AMERICAN TEMPERATE ESTUARIES

    EPA Science Inventory

    Thalassinid burrowing shrimp (predominantly, Neotrypaea californiensis and Upogebia pugettensis) inhabit large expanses of tide flats in North American Pacific estuaries, from British Columbia to Baja California. Feeding, burrowing, and burrow irrigation by burrowing shrimp can ...

  18. Transient-state mechanisms of wind-induced burrow ventilation.

    PubMed

    Turner, J Scott; Pinshow, Berry

    2015-01-15

    Burrows are common animal habitations, yet living in a burrow presents physiological challenges for its inhabitants because the burrow isolates them from sources and sinks for oxygen, carbon dioxide, water vapor and ammonia. Conventionally, the isolation is thought to be overcome by either diffusion gas exchange within the burrow or some means of capturing wind energy to power steady or quasi-steady bulk flows of air through it. Both are examples of what may be called 'DC' models, namely steady to quasi-steady flows powered by steady to quasi-steady winds. Natural winds, however, are neither steady nor quasi-steady, but are turbulent, with a considerable portion of the energy contained in so-called 'AC' (i.e. unsteady) components, where wind velocity varies chaotically and energy to power gas exchange is stored in some form. Existing DC models of burrow gas exchange do not account for this potentially significant source of energy for ventilation. We present evidence that at least two AC mechanisms operate to ventilate both single-opening burrows (of the Cape skink, Trachylepis capensis) and double-opening model burrows (of Sundevall's jird, Meriones crassus). We propose that consideration of the physiological ecology and evolution of the burrowing habit has been blinkered by the long neglect of AC ventilation. PMID:25609780

  19. Burrow-generated false facies and phantom sequences

    SciTech Connect

    Wanless, H.R.; Tagett, M.

    1986-05-01

    Callianassa (=Ophiomorpha) and other burrowers deeply rework shallow marine sequences. Through in-situ reworking, they create false sedimentary facies and stratigraphic sequences. Callianassa's key to effectiveness is that it expels sand and mud from burrow excavations but concentrates coarse material at the base of the burrow complex. Coarse material can be derived by falling into the burrow entrance, by reworking the existing sediment sequence, or by a combination of both. Examples come from shallow marine carbonate environments of south Florida and the Turks and Caicos Islands, British West Indies. Many mudbanks in south Florida are formed as stacks of layered mudstone units 20-100 cm thick. Between events, seagrasses may recolonize, and a burrowing benthic community may repopulate the substrate. The layered mudstone beneath older areas of mudbank flats can gradually be converted to a bioturbated skeletal wackestone by the deep burrowing community. Burrowing also causes mixing of faunal assemblages. On Caicos Bank, an extensive carbonate tidal flat (3-4 m thick) is slowly being transgressed. About 1 m of tidal-flat sequence is eroded at the shoreline. The remaining 2-3 m could be preserved as part of the transgressive sequence. Callianassa burrowing, however, quickly reworks the sequence, replacing tidal-flat sands and muds with marine peloidal and skeletal sediment. Within 100 m of the shoreline, the only evidence of the tidal-flat sequence is a concentration of high-spired gastropods in Calliannassa burrows at the base of the Holocene sequence and a few patches of tidal-flat sediment that burrowers missed. What looks like a basal transgressive lag is in fact a biogenic concentrate from in-situ reworking of a now phantom sequence.

  20. Burrowing in rodents: a sensitive method for detecting behavioral dysfunction.

    PubMed

    Deacon, Robert M J

    2006-01-01

    Virtually all rodents display burrowing behavior, yet measurement of this behavior has not yet been standardized or formalized. Previously, parameters such as the latency to burrow and the complexity of the burrow systems in substrate-filled boxes in the laboratory or naturalistic outdoor environments have been assessed. We describe here a simple protocol that can quantitatively measure burrowing in laboratory rodents, using a simple apparatus that can be placed in the home cage. The test is very cheap to run and requires minimal experimenter training, yet seems sensitive to a variety of treatments, such as the early stages of prion disease in mice, mouse strain differences, lesions of the hippocampus and prefrontal cortex in mice, also effects of lipopolysaccharide and IL-1beta in rats. Other species such as hamsters, gerbils and Egyptian spiny mice also burrow in this apparatus, and with suitable size modification probably almost any burrowing animal could be tested in it. The simplicity, sensitivity and robustness of burrowing make it ideal for assessing genetically modified animals, which in most cases would be mice. The test is run from late afternoon until the next morning, but only two measurements need to be taken. PMID:17406222

  1. Detecting Burrowing Owl Bloodmeals in Pulex irritans (Siphonaptera: Pulicidae).

    PubMed

    Graham, Christine B; Eisen, Rebecca J; Belthoff, James R

    2016-03-01

    Pulex irritans L. is a cosmopolitan flea species that infests a wide variety of hosts. In North America it generally parasitizes large wild mammals, but in the Pacific Northwest an association has emerged between P. irritans and the western burrowing owl (Athene cunicularia hypugaea). While investigators have recognized this association for decades, it has not been clear if P. irritans feeds on burrowing owls, or if the owls serve exclusively as phoretic hosts. Here we describe using a real-time assay that was originally developed to identify bloodmeals in Ugandan cat fleas (Ctenocephalides felis Bouché) to detect burrowing owl DNA in P. irritans collected from burrowing owls in southern Idaho. Of 50 fleas tested, 12 had no detectable vertebrate bloodmeal. The remaining 38 (76%) contained burrowing owl DNA. The assay did not detect vertebrate DNA in unfed fleas exposed to owl or mouse pelts and is therefore unlikely to detect DNA in fleas from vertebrates that have served exclusively as phoretic hosts. We conclude that P. irritans feeds on burrowing owls. We discuss the potential implications of this finding for burrowing owl conservation and enzootic plague dynamics. PMID:26545716

  2. Employee recruitment.

    PubMed

    Breaugh, James A

    2013-01-01

    The way an organization recruits can influence the type of employees it hires, how they perform, and their retention rate. This article provides a selective review of research that has addressed recruitment targeting, recruitment methods, the recruitment message, recruiters, the organizational site visit, the job offer, and the timing of recruitment actions. These and other topics (e.g., the job applicant's perspective) are discussed in terms of their potential influence on prehire (e.g., the quality of job applicants) and posthire (e.g., new employee retention) recruitment outcomes. In reviewing research, attention is given to the current state of scientific knowledge, limitations of previous research, and important issues meriting future investigation. PMID:23121331

  3. Burrowing Criteria and Burrowing Mode Adjustment in Bivalves to Varying Geoenvironmental Conditions in Intertidal Flats and Beaches

    PubMed Central

    Sassa, Shinji; Watabe, Yoichi; Yang, Soonbo; Kuwae, Tomohiro

    2011-01-01

    The response of bivalves to their abiotic environment has been widely studied in relation to hydroenvironmental conditions, sediment types and sediment grain sizes. However, the possible role of varying geoenvironmental conditions in their habitats remains poorly understood. Here, we show that the hardness of the surficial intertidal sediments varies by a factor of 20–50 due to suction development and suction-induced void state changes in the essentially saturated states of intertidal flats and beaches. We investigated the response of two species of bivalves, Ruditapes philippinarum and Donax semigranosus, in the laboratory by simulating such prevailing geoenvironmental conditions in the field. The experimental results demonstrate that the bivalve responses depended strongly on the varying geoenvironmental conditions. Notably, both bivalves consistently shifted their burrowing modes, reducing the burrowing angle and burial depth, in response to increasing hardness, to compensate for the excessive energy required for burrowing, as explained by a proposed conceptual model. This burrowing mode adjustment was accompanied by two burrowing criteria below or above which the bivalves accomplished vertical burrowing or failed to burrow, respectively. The suitable and fatal conditions differed markedly with species and shell lengths. The acute sensitivities of the observed bivalve responses to geoenvironmental changes revealed two distinctive mechanisms accounting for the adult–juvenile spatial distributions of Ruditapes philippinarum and the behavioral adaptation to a rapidly changing geoenvironment of Donax semigranosus. The present results may provide a rational basis by which to understand the ensuing, and to predict future, bivalve responses to geoenvironmental changes in intertidal zones. PMID:21957474

  4. SPATIAL DISTRIBUTIONS OF BURROWING SHRIMP POPULATIONS IN TWO OREGON ESTUARIES

    EPA Science Inventory

    Thalassinid burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) inhabit large expanses of Pacific estuarine tide flats, from British Columbia to Baja California. The spatial distribution of shrimp populations within estuaries has rarely been quantified because ...

  5. GENETIC CHARACTERIZATION OF A BURROWING SHRIMP (NEOTRYPAEA CALIFORNIENSIS)

    EPA Science Inventory

    Ghost shrimp, (Neotypaea californiensis) are burrowers, whose bioturbation and sediment destabilizations have a negative effect on mariculture of the commercially important oyster (Crassostrea gigas). Oyster farmers in Washington and Oregon estuaries have been poisoning these shr...

  6. MAPPING BURROWING SHRIMP AND SEAGRASS IN YAQUINA ESTUARY

    EPA Science Inventory

    Burrowing shrimp and seagrasses create extensive intertidal and shallow subtidal habitats within Pacific NW estuaries. Maps of their populations are useful to inform estuarine managers of locations that deserve special consideration for conservation, and to inform oyster farmers...

  7. Burrowing in marine muds by crack propagation: kinematics and forces.

    PubMed

    Dorgan, Kelly M; Arwade, Sanjay R; Jumars, Peter A

    2007-12-01

    The polychaete Nereis virens burrows through muddy sediments by exerting dorsoventral forces against the walls of its tongue-depressor-shaped burrow to extend an oblate hemispheroidal crack. Stress is concentrated at the crack tip, which extends when the stress intensity factor (KI) exceeds the critical stress intensity factor (KIc). Relevant forces were measured in gelatin, an analog for elastic muds, by photoelastic stress analysis, and were 0.015+/-0.001 N (mean +/- s.d.; N=5). Measured elastic moduli (E) for gelatin and sediment were used in finite element models to convert the forces in gelatin to those required in muds to maintain the same body shapes observed in gelatin. The force increases directly with increasing sediment stiffness, and is 0.16 N for measured sediment stiffness of E=2.7 x 10(4) Pa. This measurement of forces exerted by burrowers is the first that explicitly considers the mechanical behavior of the sediment. Calculated stress intensity factors fall within the range of critical values for gelatin and exceed those for sediment, showing that crack propagation is a mechanically feasible mechanism of burrowing. The pharynx extends anteriorly as it everts, extending the crack tip only as far as the anterior of the worm, consistent with wedge-driven fracture and drawing obvious parallels between soft-bodied burrowers and more rigid, wedge-shaped burrowers (i.e. clams). Our results raise questions about the reputed high energetic cost of burrowing and emphasize the need for better understanding of sediment mechanics to quantify external energy expenditure during burrowing. PMID:18025018

  8. Baited lines: An active nondestructive collection method for burrowing crayfish

    USGS Publications Warehouse

    Loughman, Zachary J.; Foltz, David A., II; Welsh, Stuart

    2013-01-01

    A new method (baited lines) is described for the collection of burrowing crayfishes, where fishing hooks baited with earthworms and tied to monofilament leaders are used to lure crayfishes from their burrow entrances. We estimated capture rates using baited lines at four locations across West Virginia for a total of four crayfish taxa; the taxa studied were orange, blue, and blue/orange morphs of Cambarus dubius (Upland Burrowing Catfish), and C. thomai (Little Brown Mudbug). Baited-line capture rates were lowest for C. thomai (81%; n = 21 attempts) and highest for the orange morph ofC. dubius (99%; n = 13 attempts). The pooled capture rate across all taxa was 91.5% (n = 50 attempts). Baited lines represent an environmentally nondestructive method to capture burrowing crayfishes without harm to individuals, and without disturbing burrows or the surrounding area. This novel method allows for repeat captures and long-term studies, providing a useful sampling method for ecological studies of burrowing crayfishes.

  9. Function of Hexagenia (Mayfly) Burrows: Fluid Model Suggests Bacterial Gardening

    NASA Astrophysics Data System (ADS)

    Traynham, B.; Furbish, D.; Miller, M.; White, D.

    2006-12-01

    Lake and stream bottoms experience an array of physical, chemical, and biological processes that create spatial variations both in the fluid column and in the sediment that provide a physical template for distinct niches. Burrowing insects are major ecological engineers of communities where they structure large areas of the benthic habitat through bioturbation and other activities including respiration, feeding, and defecation. The burrowing mayfly Hexagenia, when present in high densities, has a large impact on food-web dynamics and provides essential ecosystem services within the fluid column and benthic substrate, including sediment mixing, nutrient cycling, and ultimately, energy flow through the freshwater food web. It has long been recognized that particular benthic species are important in linking detrital energy resources to higher trophic levels and for determining how organic matter is processed in freshwater ecosystems; however, the unique contributions made by individual benthic species is largely absent from the literature. Here we present a model that describes the structure and function of a Hexagenia burrow. If testing supports this hypothesis, the model suggests that when high food concentration is available to Hexagenia, there exists a favorable tube length for harvesting bacteria that grow on the burrow walls. The burrow microhabitat created by Hexagenia serves as a case-study in understanding the influence of benthic burrowers on both energy flow through freshwater food webs and nutrient cycling.

  10. Vestibular recruitment

    NASA Technical Reports Server (NTRS)

    Tsemakhov, S. G.

    1980-01-01

    Vestibular recruitment is defined through the analysis of several references. It is concluded that vestibular recruitment is an objective phenomenon which manifests itself during the affection of the vestibular receptor and thus serves as a diagnostic tool during affection of the vestibular system.

  11. Resident recruitment.

    PubMed

    Longmaid, H Esterbrook

    2003-02-01

    This article has introduced the reader to the critical components of successful recruitment of radiology residents. With particular attention to the ACGME institutional and program requirements regarding resident recruitment, and an explanation of the support systems (ERAS and NRMP) currently available to those involved in applicant review and selection, the article has sought to delineate a sensible approach to recruitment. Successful recruiters have mastered the essentials of these programs and have learned to adapt the programs to their needs. As new program directors work with their departments' resident selection committees, they will identify the factors that faculty and current residents cite as most important in the successful selection of new residents. By structuring the application review process, exploiting the power of the ERAS, and crafting a purposeful and friendly interview process, radiology residency directors can find and recruit the residents who best match their programs. PMID:12585436

  12. Use of Artificial Burrows by Burrowing Owls (Athene cunicularia) at the HAMMER Facility on the U.S. Department of Energy Hanford Site

    SciTech Connect

    Alexander, Amanda K.; Sackschewsky, Michael R.; Duberstein, Corey A.

    2005-09-30

    In 2003 the U.S. Department of Energy (DOE) constructed an Emergency Vehicle Operations Course (EVOC) at the Hazardous Material Management and Emergency Response Training and Education Center (HAMMER) in the southern portion of the Hanford Site. Preliminary surveys during 2001 identified an active burrowing owl (Athene cunicularia) burrow and three burrowing owls within the proposed development area. Burrowing owls were classified as a federal species of concern, a Washington State ?candidate? species, a Washington Department of Fish and Wildlife priority species, and a Hanford Site Biological Resources Management Plan Level III resource. Therefore, the mitigation action plan for the project included the installation of twenty artificial burrows around EVOC in the spring of 2003. The mitigation plan established a success criterion of five percent annual use of the burrows by owls. In July 2005, a field survey of the EVOC burrow complex was conducted to determine use and demography at each site. Burrow locations were mapped and signs of activity (feces, owl tracks, castings, feathers) were recorded. Out of the twenty burrows, twelve were found to be active. Of the eight inactive burrows three appeared to have been active earlier in the 2005 breeding season. A total of nineteen owls were counted but demography could not be determined. It appears that the EVOC mitigation exceeded burrow use goals during 2005. Continued site monitoring and maintenance, according to mitigation plan guidelines should be conducted as prescribed.

  13. Mechanics and kinematics of backward burrowing by the polychaete Cirriformia moorei.

    PubMed

    Che, James; Dorgan, Kelly M

    2010-12-15

    The polychaete Cirriformia moorei burrows in muddy sediments by fracture, using its hydrostatic skeleton to expand its anterior region and exert force against its burrow wall to extend a crack. Burrowing occurs in four phases: stretching forward into the burrow, extending the crack anteriorly, thickening the burrowing end to amplify stress at the tip of the crack, and bringing the rest of the body forward as a peristaltic wave travels posteriorly. Here, we show that C. moorei is also able to burrow with its posterior end using a similar mechanism of crack propagation and exhibiting the same four phases of burrowing. Worms burrowed backwards with similar speeds and stress intensity factors as forward burrowing, but were thinner and less blunt and did not slip as far away from the crack tip between cycles of burrowing. The anterior end is more muscular and rigid, and differences in body shapes are consistent with having reduce musculature to dilate the posterior segments while burrowing. Backward burrowing provides a unique opportunity to study the effects of morphology on burrowing mechanics within the same species under identical conditions. PMID:21113009

  14. Collection of mammal manure and other Debris by nesting Burrowing Owls

    USGS Publications Warehouse

    Smith, M.D.; Conway, C.J.

    2011-01-01

    Burrowing Owls (Athene cunicularia) routinely collect and scatter dry manure of mammals around their nesting burrows. Recent studies have suggested this behavior attracts insect prey to the nesting burrow. However, some Burrowing Owls do not use manure, but instead, collect and scatter other materials (e.g., grass, moss, paper, plastic) around their nesting burrow in a similar fashion. Use of these materials seemingly contradicts the prey-attraction hypothesis. Using observational and experimental methods, we tested whether Burrowing Owls preferred manure to other materials commonly found at nesting burrows in eastern Washington. We found a wide variety of materials at nests, but grass and manure were the most common materials. The amount of manure present at nests was negatively correlated with the amount of other materials, and with the distance to the nearest source of manure. Burrowing Owls showed no preference between horse manure and grass divots at experimental supply stations that we placed near nesting burrows. They did prefer these two materials to carpet pieces and aluminum foil (both materials that are often found at Burrowing Owl nests). Our results did not support the premise that Burrowing Owls specifically seek out manure when lining their nesting burrows. The unusual behavior of collecting and scattering mammal manure and other debris at Burrowing Owl nests may serve functions other than (or in addition to) prey attraction and alternative hypotheses need further testing before the function of this behavior is certain. ?? 2011 The Raptor Research Foundation, Inc.

  15. Factors influencing nesting success of burrowing owls in southeastern Idaho

    SciTech Connect

    Gleason, R.S.; Johnson, D.R.

    1985-01-31

    A burrowing owl (Athene cunicularia) population nesting on the Idaho National Engineering Laboratory (INEL) in southeastern Idaho utilized burrows excavated by badgers (Taxidea taxus) or natural cavities in lava flows as nesting sites. The size of the population was small (N = 13-14 pairs) in relation to the number of available nesting sites, suggesting that factors other than burrow availability limited this population. Rodents and Jerusalem crickets (Stenopelmatus fuscus) represented the primary prey utilized during the nesting season. This population demonstrated both a numerical (brood size) and functional (dietary) response to a decrease in the density of three species of rodents on the INEL during a drought in 1977. 11 references, 1 figure, 2 table.

  16. Infaunal Burrows Are Enrichment Zones for Vibrio parahaemolyticus▿†

    PubMed Central

    Gamble, Megan D.; Lovell, Charles R.

    2011-01-01

    Vibrio parahaemolyticus, a species that includes strains known to be pathogenic in humans, and other Vibrionaceae are common, naturally occurring bacteria in coastal environments. Understanding the ecology and transport of these organisms within estuarine systems is fundamental to predicting outbreaks of pathogenic strains. Infaunal burrows serve as conduits for increased transport of tidal waters and V. parahaemolyticus cells by providing large open channels from the sediment to salt marsh tidal creeks. An extensive seasonal study was conducted at the North Inlet Estuary in Georgetown, SC, to quantify Vibrionaceae and specifically V. parahaemolyticus bacteria in tidal water, fiddler crab (Uca pugilator, Uca pugnax) burrow water, and interstitial pore water. Numbers of V. parahaemolyticus bacteria were significantly higher within burrow waters (4,875 CFU ml−1) than in creek water (193 CFU ml−1) and interstitial pore water (128 CFU ml−1), demonstrating that infaunal burrows are sites of V. parahaemolyticus enrichment. A strong seasonal trend of increased abundances of Vibrionaceae and V. parahaemolyticus organisms during the warmer months of May through September was observed. Multilocus sequence typing (MLST) analysis of isolates presumed to be V. parahaemolyticus from creek water, pore water, and burrow water identified substantial strain-level genetic variability among V. parahaemolyticus bacteria. Analysis of carbon substrate utilization capabilities of organisms presumed to be V. parahaemolyticus also indicated physiological diversity within this clade, which helps to explain the broad distribution of these strains within the estuary. These burrows are “hot spots” of Vibrionaceae and V. parahaemolyticus cell numbers and strain diversity and represent an important microhabitat. PMID:21478307

  17. Infaunal burrows are enrichment zones for Vibrio parahaemolyticus.

    PubMed

    Gamble, Megan D; Lovell, Charles R

    2011-06-01

    Vibrio parahaemolyticus, a species that includes strains known to be pathogenic in humans, and other Vibrionaceae are common, naturally occurring bacteria in coastal environments. Understanding the ecology and transport of these organisms within estuarine systems is fundamental to predicting outbreaks of pathogenic strains. Infaunal burrows serve as conduits for increased transport of tidal waters and V. parahaemolyticus cells by providing large open channels from the sediment to salt marsh tidal creeks. An extensive seasonal study was conducted at the North Inlet Estuary in Georgetown, SC, to quantify Vibrionaceae and specifically V. parahaemolyticus bacteria in tidal water, fiddler crab (Uca pugilator, Uca pugnax) burrow water, and interstitial pore water. Numbers of V. parahaemolyticus bacteria were significantly higher within burrow waters (4,875 CFU ml(-1)) than in creek water (193 CFU ml(-1)) and interstitial pore water (128 CFU ml(-1)), demonstrating that infaunal burrows are sites of V. parahaemolyticus enrichment. A strong seasonal trend of increased abundances of Vibrionaceae and V. parahaemolyticus organisms during the warmer months of May through September was observed. Multilocus sequence typing (MLST) analysis of isolates presumed to be V. parahaemolyticus from creek water, pore water, and burrow water identified substantial strain-level genetic variability among V. parahaemolyticus bacteria. Analysis of carbon substrate utilization capabilities of organisms presumed to be V. parahaemolyticus also indicated physiological diversity within this clade, which helps to explain the broad distribution of these strains within the estuary. These burrows are "hot spots" of Vibrionaceae and V. parahaemolyticus cell numbers and strain diversity and represent an important microhabitat. PMID:21478307

  18. Novel use of burrow casting as a research tool in deep-sea ecology

    PubMed Central

    Seike, Koji; Jenkins, Robert G.; Watanabe, Hiromi; Nomaki, Hidetaka; Sato, Kei

    2012-01-01

    Although the deep sea is the largest ecosystem on Earth, its infaunal ecology remains poorly understood because of the logistical challenges. Here we report the morphology of relatively large burrows obtained by in situ burrow casting at a hydrocarbon-seep site and a non-seep site at water depths of 1173 and 1455 m, respectively. Deep and complex burrows are abundant at both sites, indicating that the burrows introduce oxygen-rich sea water into the deep reducing substrate, thereby influencing benthic metabolism and nutrient fluxes, and providing an oxic microhabitat for small organisms. Burrow castings reveal that the solemyid bivalve Acharax johnsoni mines sulphide from the sediment, as documented for related shallow-water species. To our knowledge, this is the first study to examine in situ burrow morphology in the deep sea by means of burrow casting, providing detailed information on burrow structure which will aid the interpretation of seabed processes in the deep sea. PMID:22298806

  19. Novel use of burrow casting as a research tool in deep-sea ecology.

    PubMed

    Seike, Koji; Jenkins, Robert G; Watanabe, Hiromi; Nomaki, Hidetaka; Sato, Kei

    2012-08-23

    Although the deep sea is the largest ecosystem on Earth, its infaunal ecology remains poorly understood because of the logistical challenges. Here we report the morphology of relatively large burrows obtained by in situ burrow casting at a hydrocarbon-seep site and a non-seep site at water depths of 1173 and 1455 m, respectively. Deep and complex burrows are abundant at both sites, indicating that the burrows introduce oxygen-rich sea water into the deep reducing substrate, thereby influencing benthic metabolism and nutrient fluxes, and providing an oxic microhabitat for small organisms. Burrow castings reveal that the solemyid bivalve Acharax johnsoni mines sulphide from the sediment, as documented for related shallow-water species. To our knowledge, this is the first study to examine in situ burrow morphology in the deep sea by means of burrow casting, providing detailed information on burrow structure which will aid the interpretation of seabed processes in the deep sea. PMID:22298806

  20. ENHANCED ORGANIC MATTER REMINERALIZATION AND NUTRIENT TURNOVER BY POPULATIONS OF BURROWING SHRIMP IN YAQUINA BAY, OR

    EPA Science Inventory

    Burrowing, or thalassinid, shrimp structure large areas of intertidal habitat of Pacific Northwest estuaries. This field study utilized a combination of anoxic incubations, porewater dialysis peepers, and benthic chambers to quantify the role of burrowing shrimp species on OM dec...

  1. Population structure and seasonal intra-burrow movement of Ornithodoros turicata (Acari: Argasidae) in gopher tortoise burrows.

    PubMed

    Adeyeye, O A; Butler, J F

    1989-07-01

    Burrows of the gopher tortoise, Gopherus polyphemus Daudin, were sampled for Ornithodoros turicata (Dugès) infestation using carbon dioxide baits and vacuum extraction. Ticks were captured, marked, released, and recaptured, and population estimates were made using the Lincoln index. Estimated population ranged from 47 to 1,338 ticks per burrow. The tick population consisted predominantly of nymphs, with a significant increase in the larval population during the months of June and July. Adult sex ratio was slightly male-biased, but numbers of adults collected were consistently low. Ticks exhibited a low interburrow movement, but depth preferences fluctuated with season; more ticks occurred in the upper strata of the burrows during the hot, humid months. PMID:2769706

  2. Burrowing behavior in mud and sand of morphologically divergent polychaete species (Annelida: Orbiniidae).

    PubMed

    Francoeur, Alex A; Dorgan, Kelly M

    2014-04-01

    Muddy and sandy sediments have different physical properties. Muds are cohesive elastic solids, whereas granular beach sands are non-cohesive porous media. Infaunal organisms such as worms that burrow through sediments therefore face different mechanical challenges that potentially lead to a variety of burrowing strategies and morphologies. In this study we compared three morphologically distinct polychaete species representing different clades in the family Orbiniidae and related differences in their burrowing behaviors and morphologies to their natural environments (mud or sand). Worms burrowed in transparent analogs for muds and sands, and kinematic analysis showed differences both among species and between materials. Leitoscoloplos pugettensis lives in mud and burrows by fracture, using its pointed head to concentrate stress at the tip of the burrow. Naineris dendritica lives in sand and uses its broader head that fluctuates in width over a burrowing cycle to decrease backward slipping in sand, potentially preventing burrow collapse. Orbinia johnsoni lives in sand and uses internal body expansions to pack sand grains, another mechanism to prevent burrow collapse. By combining data from species and materials to obtain a broad range of burrowing velocities, we show that burrowing worms control their velocity by increasing or decreasing their burrowing frequency rather than by altering cycle distance as shown previously for crawling earthworms. This study demonstrates how fairly small evolutionary divergences in morphologies and behaviors facilitate locomotion in environments with different physical constraints. PMID:24797095

  3. A sand layer deters burrowing by Lumbricus terrestris L.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effectiveness of septic system filter fields can be reduced by preferential flow through soil macropores. Burrows of anecic earthworms may contribute to this concern by penetrating the infiltrative surface of soil-wastewater-treatment-system trenches. Adding a layer of sand on the bottom of th...

  4. Burrowing shrimp as foundation species in NE Pacific estuaries

    EPA Science Inventory

    My talk will be about the my research to characterize the role that burrowing shrimp play as foundation/engineering species in Pacific NW estuaries. My research has focused on measuring the abundance & distribution of two species (ghost shrimp & mud shrimp) at ecosystem scales, ...

  5. Microstructural view of burrowing with a bioinspired digging robot.

    PubMed

    Nordstrom, K N; Dorsch, D S; Losert, W; Winter, A G

    2015-10-01

    RoboClam is a burrowing technology inspired by Ensis directus, the Atlantic razor clam. Atlantic razor clams should only be strong enough to dig a few centimeters into the soil, yet they burrow to over 70 cm. The animal uses a clever trick to achieve this: by contracting its body, it agitates and locally fluidizes the soil, reducing the drag and energetic cost of burrowing. RoboClam technology, which is based on the digging mechanics of razor clams, may be valuable for subsea applications that could benefit from efficient burrowing, such as anchoring, mine detonation, and cable laying. We directly visualize the movement of soil grains during the contraction of RoboClam, using a novel index-matching technique along with particle tracking. We show that the size of the failure zone around contracting RoboClam can be theoretically predicted from the substrate and pore fluid properties, provided that the timescale of contraction is sufficiently large. We also show that the nonaffine motions of the grains are a small fraction of the motion within the fluidized zone, affirming the relevance of a continuum model for this system, even though the grain size is comparable to the size of RoboClam. PMID:26565232

  6. Microstructural view of burrowing with a bioinspired digging robot

    NASA Astrophysics Data System (ADS)

    Nordstrom, K. N.; Dorsch, D. S.; Losert, W.; Winter, A. G.

    2015-10-01

    RoboClam is a burrowing technology inspired by Ensis directus, the Atlantic razor clam. Atlantic razor clams should only be strong enough to dig a few centimeters into the soil, yet they burrow to over 70 cm. The animal uses a clever trick to achieve this: by contracting its body, it agitates and locally fluidizes the soil, reducing the drag and energetic cost of burrowing. RoboClam technology, which is based on the digging mechanics of razor clams, may be valuable for subsea applications that could benefit from efficient burrowing, such as anchoring, mine detonation, and cable laying. We directly visualize the movement of soil grains during the contraction of RoboClam, using a novel index-matching technique along with particle tracking. We show that the size of the failure zone around contracting RoboClam can be theoretically predicted from the substrate and pore fluid properties, provided that the timescale of contraction is sufficiently large. We also show that the nonaffine motions of the grains are a small fraction of the motion within the fluidized zone, affirming the relevance of a continuum model for this system, even though the grain size is comparable to the size of RoboClam.

  7. Microstructural view of burrowing with a bioinspired digging robot

    NASA Astrophysics Data System (ADS)

    Nordstrom, Kerstin; Dorsch, Dan; Losert, Wolfgang; Winter, V., Amos

    RoboClam is a burrowing technology inspired by Ensis directus, the Atlantic razor clam. Atlantic razor clams should only be strong enough to dig a few centimeters into the soil, yet they burrow to over 70 cm. The animal uses a clever trick to achieve this: by contracting its body, it agitates and locally fluidizes the soil, reducing the drag and energetic cost of burrowing. RoboClam technology, which is based on the digging mechanics of razor clams, may be valuable for subsea applications that could benefit from efficient burrowing, such as anchoring, mine detonation, and cable laying. We directly visualize the movement of soil grains during the contraction of RoboClam, using a novel index-matching technique along with particle tracking. We show that the size of the failure zone around contracting RoboClam can be theoretically predicted from the substrate and pore fluid properties, provided that the timescale of contraction is sufficiently large. We also show that the nonaffine motions of the grains are a small fraction of the motion within the fluidized zone, affirming the relevance of a continuum model for this system, even though the grain size is comparable to the size of RoboClam.

  8. Partitioning of habitable pore space in earthworm burrows.

    PubMed

    Gorres, Josef H; Amador, Jose A

    2010-03-01

    Earthworms affect macro-pore structure of soils. However, some studies suggest that earthworm burrow walls and casts themselves differ greatly in structure from surrounding soils, potentially creating habitat for microbivorours nematodes which accelerate the decomposition and C and N mineralization. In this study aggregates were sampled from the burrow walls of the anecic earthworm Lumbricus terrestris and bulk soil (not altered by earthworms) from mesocosm incubated in the lab for 0, 1, 3, 5 and 16 weeks. Pore volumes and pore sizes were measured in triplicate with Mercury Intrusion Porosimetry (MIP). This method is well suited to establish pore size structure in the context of habitat, because it measures the stepwise intrusion of mercury from the outside of the aggregate into ever smaller pores. The progress of mercury into the aggregate interior thus resembles potential paths of a nematode into accessible habitable pore spaces residing in an aggregate. Total specific pore volume, V(s), varied between 0.13 and 0.18 mL/g and increased from 3 to 16 weeks in both burrow and bulk soil. Differences between total V(s) of bulk and burrow samples were not significant on any sampling date. However, differences were significant for pore size fractions at the scale of nematode body diameter. PMID:22736839

  9. Shrimp burrow in tropical seagrass meadows: An important sink for litter

    NASA Astrophysics Data System (ADS)

    Vonk, Jan Arie; Kneer, Dominik; Stapel, Johan; Asmus, Harald

    2008-08-01

    The abundance, burrow characteristics, and in situ behaviour of the burrowing shrimps Neaxius acanthus (Decapoda: Strahlaxiidae) and Alpheus macellarius (Decapoda: Alpheidae) were studied to quantify the collection of seagrass material, to identify the fate of this collected material, and to determine the importance of these burrowing crustaceans in the nutrient (nitrogen and phosphorus) cycling of two tropical seagrass meadows on Bone Batang, South Sulawesi, Indonesia. Alpheus macellarius harvested 0.70 g dry weight (DW) burrow -1 d -1 seagrass material, dominantly by active cutting of fresh seagrass leaves. Neaxius acanthus collected 1.66 g DW burrow -1 d -1, mainly detached leaves which floated past the burrow opening. The A. macellarius and N. acanthus communities together collected in their burrows an amount of seagrass leaf material corresponding to more than 50% of the leaf production in the meadows studied. The crustacean species studied might therefore fulfil an important function in the nutrient cycling of tropical meadows. In the burrow most of the collected material is shredded into pieces. The burrows of both species had special chambers which serve as a storage for seagrass leaf material. Neaxius acanthus incorporated most of the material into the burrow wall lining, which is made of small sediment particles and macerated seagrass leaves. Phosphate concentrations measured in N. acanthus burrows compared with pore-water and water-column concentrations suggests that a substantial amount of the seagrass material undergoes decomposition in the burrows. Oxygen levels measured in these water bodies are indicative for a possible exchange of water between the burrow and its surroundings, most likely supported by the shrimps irrigating their burrows. By collecting leaf material in their burrows, nutrients that are otherwise lost from the seagrass meadow associated with detached leaves and leaf fragments carried away in the water column, are maintained in the

  10. Surface destabilisation by the invasive burrowing engineer Mus musculus on a sub-Antarctic island

    NASA Astrophysics Data System (ADS)

    Eriksson, Bert; Eldridge, David J.

    2014-10-01

    Invasive species are known to have substantial trophic effects on ecosystems and ecosystem processes. The invasion of the house mouse (Mus musculus) onto sub-Antarctic islands has had a devastating effect on plants, invertebrates, and birds with substantial changes in ecosystem functions. Less well understood, however, are the nontrophic, geomorphic effects of mice resulting from their burrowing activities. We examined the extent of burrow construction by M. musculus across an area of about 20 ha on Marion Island and the effects of burrows on water flow and sediment movement. We recorded a density of 0.59 ± 0.48 (mean ± SD) burrows m- 2, with more burrows at lower altitudes and shallower slopes, and twice the density in the solifluction risers (0.86 ± 0.54 m- 2) than the intervening terraces or treads (0.40 ± 0.51 m- 2). Most burrows were dug horizontally into the slope and tended to extend about 20 cm deep before turning. A very conservative estimate of sediment removed from burrows from this depth is 2.4 t ha- 1. However, taking into account more detailed data on burrow morphology based on excavations, actual amounts may be closer to 8.4 t ha- 1. Average soil displacement rate for a single burrow, measured over 5 days, was 0.18 kg burrow- 1 day- 1. Burrows acted as conduits for water and warmer air. Stones at burrow entrances were moved eight times farther by water (10.4 cm) than those not associated with burrows. Similarly, temperatures adjacent to burrow entrances were 4.1 °C higher than sites 10 cm away. Together our data indicate that mice are having substantial deleterious and geomorphic effects on sub-Antarctic ecosystems through their burrowing. With lower rates of mouse mortality resulting from warmer climates predicted under global climate models, we can expect an increase in damage resulting from mouse activity.

  11. Advection around ventilated U-shaped burrows: A model study

    NASA Astrophysics Data System (ADS)

    Brand, Andreas; Lewandowski, JöRg; Hamann, Enrico; Nützmann, Gunnar

    2013-05-01

    Advective transport in the porous matrix of sediments surrounding burrows formed by fauna such as Chironomus plumosus has been generally neglected. A positron emission tomography study recently revealed that the pumping activity of the midge larvae can indeed induce fluid flow in the sediment. We present a numerical model study which explores the conditions at which advective transport in the sediment becomes relevant. A 0.15 m deep U-shaped burrow with a diameter of 0.002 m within the sediment was represented in a 3-D domain. Fluid flow in the burrow was calculated using the Navier-Stokes equation for incompressible laminar flow in the burrow, and flow in the sediment was described by Darcy's law. Nonreactive and reactive transport scenarios were simulated considering diffusion and advection. The pumping activity of the model larva results in considerable advective flow in the sediment at reasonable high permeabilities with flow velocities of up to 7.0 × 10-6 m s-1 close to the larva for a permeability of 3 × 10-12 m2. At permeabilities below 7 × 10-13 m2 advection is negligible compared to diffusion. Reactive transport simulations using first-order kinetics for oxygen revealed that advective flux into the sediment downstream of the pumping larva enhances sedimentary uptake, while the advective flux into the burrow upstream of the larvae inhibits diffusive sedimentary uptake. Despite the fact that both effects cancel each other with respect to total solute uptake, the advection-induced asymmetry in concentration distribution can lead to a heterogeneous solute and redox distribution in the sediment relevant to complex reaction networks.

  12. Factors affecting detection of burrowing owl nests during standardized surveys

    USGS Publications Warehouse

    Conway, C.J.; Garcia, V.; Smith, M.D.; Hughes, K.

    2008-01-01

    Identifying causes of declines and evaluating effects of management practices on persistence of local populations of burrowing owls (Athene cunicularia) requires accurate estimates of abundance and population trends. Moreover, regulatory agencies in the United States and Canada typically require surveys to detect nest burrows prior to approving developments or other activities in areas that are potentially suitable for nesting burrowing owls. In general, guidelines on timing of surveys have been lacking and surveys have been conducted at different times of day and in different stages of the nesting cycle. We used logistic regression to evaluate 7 factors that could potentially affect probability of a surveyor detecting a burrowing owl nest. We conducted 1,444 detection trials at 323 burrowing owl nests within 3 study areas in Washington and Wyoming, USA, between February and August 2000-2002. Detection probability was highest during the nestling period and increased with ambient temperature. The other 5 factors that we examined (i.e., study area, time of day, timing within the breeding season, wind speed, % cloud cover) interacted with another factor to influence detection probability. Use of call-broadcast surveys increased detection probability, even during daylight hours when we detected >95% of owls visually. Optimal timing of surveys will vary due to differences in breeding phenology and differences in nesting behavior across populations. Nevertheless, we recommend ???3 surveys per year: one that coincides with the laying and incubation period, another that coincides with the early nestling period, and a third that coincides with the late nestling period. In northern latitudes, surveys can be conducted throughout the day.

  13. Crab Burrows are Important Conduits for Groundwater Recharge in Bangladesh

    NASA Astrophysics Data System (ADS)

    Stahl, M.; Tarek, M. H.; Yeo, D. C.; Badruzzaman, A.; Harvey, C. F.

    2013-12-01

    Recent research suggests that recharge from man-made ponds may stimulate arsenic mobilization within Bangladeshi aquifers. Man-made ponds are widespread throughout Bangladesh and are generally underlain by low permeability clays that could potentially limit flow to the sandy aquifer below if they are not compromised by preferential flow paths. Animal borrows are one common type of preferential flow path through surface clays. Across the Ganges Delta, terrestrial crabs dig borrows, sometimes as long as 10 meters. In our study pond in Munshiganj, Bangladesh we found crab burrows extending through the surficial clays and down into the shallow aquifer spaced approximately every meter. We use these field observations along with a novel, coupled isotope and water balance model to quantify the fluxes into and out of the pond. We show that nearly all of the aquifer recharge from the pond is through crab burrows which have enhanced the hydraulic conductivity of the surficial sediments by several orders of magnitude. In addition we show that the recharging pond water is shifting the solute composition of water beneath the pond. We suggest that, as a result of crab burrows, young ponds may contribute large fluxes of recharge water whereas older ponds may contribute little recharge to the aquifer. All terrestrial crabs have gills that must remain moist to allow for respiration. So, to ensure an uninterrupted water source, their borrows must reach the maximum depth that the water table drops to seasonally after irrigation ceases and before the onset of the monsoon. Once a pond is installed crabs living within the sediments that now make up the new pond bottom would no longer need to construct burrows to ensure a constant supply of water. Over time, burrows that existed prior to pond construction can clog. Water balance data for an old pond at our study site indicates that this pond contributes less recharge than our newly constructed pond.

  14. Multiscale habitat selection by burrowing owls in black-tailed prairie dog colonies

    USGS Publications Warehouse

    Lantz, S.J.; Conway, C.J.; Anderson, S.H.

    2007-01-01

    Some populations of western burrowing owls (Athene cunicularia hypugaea) have declined in recent decades. To design and implement effective recovery efforts, we need a better understanding of how distribution and demographic traits are influenced by habitat quality. To this end, we measured spatial patterns of burrowing owl breeding habitat selection within black-tailed prairie dog (Cynomys ludovicianus) colonies in northeastern Wyoming, USA. We compared burrow-, site-, colony-, and landscape-scale habitat parameters between burrowing owl nest burrows (n = 105) and unoccupied burrows (n = 85). We sampled 4 types of prairie dog colonies: 1) owl-occupied, active with prairie dogs (n = 16); 2) owl-occupied, inactive (n = 13); 3) owl-unoccupied, active (n = 14); and 4) owl-unoccupied, inactive (n = 14). We used an information-theoretic approach to examine a set of candidate models of burrowing owl nest-site selection. The model with the most support included variables at all 4 spatial scales, and results were consistent among the 4 types of prairie dog colonies. Nest burrows had longer tunnels, more available burrows within 30 m, and less shrub cover within 30 m, more prairie dog activity within 100 m, and were closer to water than unoccupied burrows. The model correctly classified 76% of cases, all model coefficients were stable, and the model had high predictive ability. Based on our results, we recommend actions to ensure persistence of the remaining prairie dog colonies as an important management strategy for burrowing owl conservation in the Great Plains of North America.

  15. Seasonal changes in burrow geometry of the common mole rat (Rodentia: Bathyergidae)

    NASA Astrophysics Data System (ADS)

    Thomas, H. G.; Scantlebury, M.; Swanepoel, D.; Bateman, P. W.; Bennett, N. C.

    2013-11-01

    Sociality in mole rats has been suggested to have evolved as a response to the widely dispersed food resources and the limited burrowing opportunities that result from sporadic rainfall events. In the most arid regions, individual foraging efficiency is reduced, and energetic constraints increase. In this study, we investigate seasonal differences in burrow architecture of the social Cryptomys hottentotus hottentotus in a mesic region. We describe burrow geometry in response to seasonal weather conditions for two seasons (wet and dry). Interactions occurred between seasons and colony size for the size of the burrow systems, but not the shape of the burrow systems. The fractal dimension values of the burrow systems did not differ between seasons. Thus, the burrow complexity was dependent upon the number of mole rats present in the social group.

  16. Rodent burrows in late Pleistocene paleosols at Korean Palaeolithic sites and their implications for paleoclimate changes

    NASA Astrophysics Data System (ADS)

    Lim, H.; Park, S.; Lee, J.; Lee, Y.

    2013-12-01

    Rodent burrows are commonly found at many Paleolithic archaeological sites in Korea. They are nearly straight in horizontal view and gently inclined in lateral view. Burrow diameters are mostly 7 - 10cm, and burrow length may reach a few meters. Vertical penetration depths are generally about 1 m from the surface, and the thickness of the burrow-bearing layer is about 1-2 m. Although no remains (bones, teeth, claws, and coprolites) were found within burrows, they are interpreted to have been produced by rodent-like mammals (probably ground squirrels) based on the size and architecture. According to the previous study, the age of these burrows was constrained to be between ca. 40,000 and 25,000 yr BP by tephrochronology, radiocarbon and optically stimulated luminescence dating results (Lim et al., 2007). However, little is known about the reason why these burrows have disappeared after late Pleistocene time. For this question, two explanations can be considered: extinction or migration. Since same kinds of burrows are still found in the high-latitude regions, such as Mongolia and North America, the possibility of extinction can be ruled out. Therefore, migration seems to be the most likely explanation. Our results show that the destruction of habitat caused by climate change during this period is the main reason for the northward migration of burrowing animals. This study suggests that rodent burrows found in the late Pleistocene paleosols can provide useful information on paleoclimate and paleoenvironmental changes.

  17. Nest site characteristics and nesting success of the Western Burrowing Owl in the eastern Mojave Desert

    USGS Publications Warehouse

    Longshore, Kathleen M.; Crowe, Dorothy E.

    2013-01-01

    We evaluated nest site selection at two spatial scales (microsite, territory) and reproductive success of Western Burrowing Owls (Athene cunicularia hypugaea) at three spatial scales (microsite, territory, landscape) in the eastern Mojave Desert. We used binary logistic regression within an information-theoretic approach to assess factors influencing nest site choice and nesting success. Microsite-scale variables favored by owls included burrows excavated by desert tortoise (Gopherus agassizii), burrows with a large mound of excavated soil at the entrance, and a greater number of satellite burrows within 5 m of the nest burrow. At the territory scale, owls preferred patches with greater cover of creosote bush (Larrea tridentata) within 50 m of the nest burrow. An interaction between the presence or absence of a calcic soil horizon layer over the top of the burrow (microsite) and the number of burrows within 50 m (territory) influenced nest site choice. Nesting success was influenced by a greater number of burrows within 5 m of the nest burrow. Total cool season precipitation was a predictor of nesting success at the landscape scale. Conservation strategies can rely on management of habitat for favored and productive nesting sites for this declining species.

  18. Water relations of the burrowing sandhill frog, Arenophryne rotunda (Myobatrachidae).

    PubMed

    Cartledge, V A; Withers, P C; Thompson, G G; McMaster, K A

    2006-05-01

    Arenophryne rotunda is a small (2-8 g) terrestrial frog that inhabits the coastal sand dunes of central Western Australia. While sand burrowing is a strategy employed by many frog species inhabiting Australia's semi-arid and arid zones, A. rotunda is unique among burrowing species because it lives independently of free water and can be found nocturnally active on the dune surface for relatively extended periods. Consequently, we examined the physiological factors that enable this unique frog to maintain water balance. A. rotunda was not found to have any special adaptation to reduce EWL (being equivalent to a free water surface) or rehydrate from water (having the lowest rehydration rate measured for 15 Western Australian frog species), but it was able to maintain water balance in sand of very low moisture (1-2%). Frogs excavated in the field were in dune sand of 4.4% moisture content, as a consequence of recent rain, which was more than adequate for these frogs to maintain water balance as reflected by their low plasma and urine osmotic concentrations. We suggest that in dry periods of the year, A. rotunda can achieve positive water balance by cutaneous water uptake by burrowing deeper into the substrate to where the percent water content is greater than 1.5%. PMID:16315052

  19. Extended amplification of acoustic signals by amphibian burrows.

    PubMed

    Muñoz, Matías I; Penna, Mario

    2016-07-01

    Animals relying on acoustic signals for communication must cope with the constraints imposed by the environment for sound propagation. A resource to improve signal broadcast is the use of structures that favor the emission or the reception of sounds. We conducted playback experiments to assess the effect of the burrows occupied by the frogs Eupsophus emiliopugini and E. calcaratus on the amplitude of outgoing vocalizations. In addition, we evaluated the influence of these cavities on the reception of externally generated sounds potentially interfering with conspecific communication, namely, the vocalizations emitted by four syntopic species of anurans (E. emiliopugini, E. calcaratus, Batrachyla antartandica, and Pleurodema thaul) and the nocturnal owls Strix rufipes and Glaucidium nanum. Eupsophus advertisement calls emitted from within the burrows experienced average amplitude gains of 3-6 dB at 100 cm from the burrow openings. Likewise, the incoming vocalizations of amphibians and birds were amplified on average above 6 dB inside the cavities. The amplification of internally broadcast Eupsophus vocalizations favors signal detection by nearby conspecifics. Reciprocally, the amplification of incoming conspecific and heterospecific signals facilitates the detection of neighboring males and the monitoring of the levels of potentially interfering biotic noise by resident frogs, respectively. PMID:27209276

  20. Distribution of burrowing owls in east-central South Dakota

    USGS Publications Warehouse

    Shaffer, Jill A; Thiele, Jason P.

    2013-01-01

    Western burrowing owl (Athene cunicularia hypugaea) populations have declined across much of western North America, particularly at the northern and eastern edges of the species’ breeding range (Martell et al. 2001, Murphy et al. 2001, Shyry et al. 2001, Skeel et al. 2001, Klute et al. 2003). In South Dakota, the burrowing owl is a summer resident that historically was relatively common throughout the state, but its range has decreased in recent decades, especially in the eastern half of the state (Whitney et al. 1978, South Dakota Ornithologists’ Union [SDOU] 1991, Peterson 1995). Tallman et al. (2002) described the species as uncommon to locally common in western South Dakota, uncommon in the north-central part of the state, and casual (i.e., not within the species’ normal range, but with 3–10 records in the past 10 years) elsewhere in the eastern half. The burrowing owl is a Species of Greatest Conservation Need (South Dakota Department of Game, Fish and Parks [SDGFP] 2006) and a Level I Priority Species in South Dakota (Bakker 2005).

  1. Diet of western Burrowing Owls wintering in southern Texas

    USGS Publications Warehouse

    Littles, C.J.; Williford, D.; Skoruppa, M.K.; Woodin, M.C.; Hickman, G.C.

    2007-01-01

    Winter diets of the western Burrowing Owl (Athene cunicularia hypugaea) are little known. We determined the diet of western Burrowing Owls wintering in southern Texas by analyzing the contents of 182 pellets collected over four winters (1999-2000, 2001-2002, 2002-2003, and 2003-2004) in three habitat types (agricultural, mainland grassland, and barrier island). Remains of a total of 7476 prey items were recovered, 98% of which were arthropods. Gryllidae (crickets) formed the largest component (50%) of the prey, followed by lepidopteran larvae (13%), beetles (8%), spiders (7%), and earwigs (6%). Although vertebrates, primarily small mammals and birds, represented only 2% of prey items by number, they represented most (71%) of the biomass. Northern pygmy mice (Baiomys taylori) and fulvous harvest mice (Reithrodontomys fulveccens) were the two most frequently consumed vertebrate species. In all habitats, arthropods, especially orthopterans, were the primary prey item by number, whereas vertebrates, primarily small mammals, were the most important by biomass. Greater consumption of arthropods by Burrowing Owls in agricultural areas may be a factor contributing to owl use of these highly altered environments. ?? 2007 The Raptor Research Foundation, Inc.

  2. Methods for monitoring tidal flushing in large animal burrows in tropical mangrove swamps

    NASA Astrophysics Data System (ADS)

    Hollins, Suzanne E.; Heron, Scott F.; Ridd, Peter V.

    2009-05-01

    The typically anaerobic nature of mangrove sediments provides significant challenges to the mangrove trees and biota inhabiting them. The burrowing activities and flow of water through the numerous and complex animal burrows perforating the sediments of mangroves have a major influence on the biogeochemistry of the sediments and are important to the enhancement of nutrient and oxygen exchange. Two new methods are presented for monitoring the tidal flushing of Sesarma messa and Alpheus cf macklay burrows in a Rhizophora stylosa mangrove forest - by measuring oxygen content of burrow water and by determining the change in fluorescence of a dye tracer through tidal inundation. A case study using the first of these showed oxygen consumption rates at the burrow wall deep within the burrow were found to be between 210 and 460 μmol O 2 m -2 h -1. The influx of oxygen during a flood tide was found to be significant and indicated that approximately 40% of the burrow water is flushed during a single tidal event. However, the high consumption rate of oxygen within the burrow resulted in the oxygen concentration remaining at or below one-third of the oxygen content of the flooding tidal water. A test application of the second method, using rhodamine dye as a tracer, indicated that the exchange of water between the burrow and the flooding tide was found to be in the order of 30% of the burrow volume. These new techniques provide a means to further study the nutrient exchange within these burrow systems and verify the initial findings that several tidal inundations are necessary to completely flush the burrows.

  3. Thalassinoides burrows (decapoda dwelling structures) in lower cretaceous sections of southwestern and central Crimea

    NASA Astrophysics Data System (ADS)

    Yanin, B. T.; Baraboshkin, E. Yu.

    2013-05-01

    Burrows of Thalassinoides, which are attributed to the group of dwelling structures, occur in all the marine and coastal facies. The Lower Cretaceous sections of southwestern and central Crimea yielded the representative collection of Thalassinoides burrows belonging to the ichnospecies Th. suevicus (Rieth, 1932), which served as an object for this investigation. The burrows are confined to coarse-grained terrigenous, carbonate, and mixed sediments and contain assemblages of ichnofossils indicating coastal and shallow-water marine Skolithos and Cruziana ichnofacies. In the Mesozoic-Cenozoic, the producers of the Thalassinoides burrows were decapods, confirmed by finds of crayfish Hoploparia in them.

  4. Likelihood of burrow flow in Canadian agricultural lands

    NASA Astrophysics Data System (ADS)

    Dadfar, Humaira; Allaire, Suzanne E.; van Bochove, Eric; Denault, Jean-Thomas; Thériault, Georges; Charles, Anaïs

    2010-05-01

    SummaryIndicators of risk of water contamination (IROWCs) by agricultural contaminants are developed to assess sustainability of agriculture. Burrow flow ( BF) is part of the transport hydrology algorithm used in IROWCs since it is a key pathway for sub-surface contaminant transport. The objectives of this study were to develop a methodology for predicting the likelihood of BF occurrence in agricultural soils across Canada at the landscape scale, and to determine its variation over a 25-year period (1981-2006). The BF algorithm considers the influence of climate, soil properties, and soil management on the likely frequency of BF and distribution of burrows ( B) made by Lumbricus terrestris L. Nova Scotia, Prince Edward Island, Ontario, Quebec, followed by New Brunswick, had the highest likelihood of BF due to favourable humidity, sufficient heat, medium-textured soils, and strong runoff during the growing season and spring thaw. Alberta and Saskatchewan are too dry to favour BF. Areas with high risk of BF fall within locations of high potential for lateral flow due to shallow soils, or to the presence of tile drainage, which may connect BF pathways to important water bodies such as the Great Lakes and the St-Lawrence River. Sensitivity analyses on threshold values used in the BF algorithm indicated that Manitoba is the most sensitive province to changes in precipitation, Quebec to temperature, Prince Edward Island to soil depth, and Ontario to manure application. The BF algorithm can be used as a simple tool to predict the likelihood of water and contaminant transport along earthworm burrows with data available across Canada. It will be upgraded with new data (e.g. climate change) and with an improved algorithm after statistical analyses and correlations with actual water quality data.

  5. The effect of water density variations on the tidal flushing of animal burrows

    NASA Astrophysics Data System (ADS)

    Heron, S. F.; Ridd, P. V.

    2003-09-01

    Animal burrows in mangrove swamps play an important role in the transport of various soluble materials, including salt. Flushing of burrows by inundating tides provides an efficient mechanism for the exchange of these materials. The density increase in the burrow, due to salt diffusion from pore water into the burrow, causes a greater resistance to the flushing. As the salinity difference between surface and burrow waters increases, the burrows no longer flush, and hydrostatic equilibrium exists between the different density waters. A flume experiment was conducted to compare burrow flushing characteristics with theoretical predictions. The results were consistent with a simple analytical theory in predicting whether burrows would flush. When equilibrium was attained, the difference between the interface depths was 10% greater than the theoretical prediction, which was within the experimental error. In addition, a comparison between a two-opening and a three-opening burrow showed that there was no benefit to the flushing capability due to additional openings. Computational fluid dynamic models were undertaken to compare with the experimental and theoretical flushing characteristics. These were also consistent with the flushing prediction theory. When equilibrium was attained, the difference between the interface depths in the model was 33% greater than the theoretical prediction. The computational study with an additional opening supported the experimental evidence that there is no advantage to the flushing. Insight into small-scale processes unable to be accurately observed could be obtained from the models, e.g. oscillations of density interfaces and turbulent scales at the burrow openings. The consistency in prediction of flushing between the theoretical, experimental and computational methods, now allows modelling of more complex burrow structures with great confidence.

  6. COMPARISON OF CARBON AND NITROGEN FLUXES IN TIDEFLAT FOOD WEBS DOMINATED BY BURROWING SHRIMP OR BY CULTURED OYSTERS

    EPA Science Inventory

    Two species of indigenous, thalassinid burrowing shrimps are pests to the benthic culture of Pacific oysters (Crassostrea gigas) because deposition of sediment excavated by the shrimps buries or smothers the oysters. Carbaryl pesticide is used to reduce burrowing shrimp densitie...

  7. Discrete genetic modules are responsible for complex burrow evolution in Peromyscus mice.

    PubMed

    Weber, Jesse N; Peterson, Brant K; Hoekstra, Hopi E

    2013-01-17

    Relative to morphological traits, we know little about how genetics influence the evolution of complex behavioural differences in nature. It is unclear how the environment influences natural variation in heritable behaviour, and whether complex behavioural differences evolve through few genetic changes, each affecting many aspects of behaviour, or through the accumulation of several genetic changes that, when combined, give rise to behavioural complexity. Here we show that in nature, oldfield mice (Peromyscus polionotus) build complex burrows with long entrance and escape tunnels, and that burrow length is consistent across populations, although burrow depth varies with soil composition. This burrow architecture is in contrast with the small, simple burrows of its sister species, deer mice (P. maniculatus). When investigated under laboratory conditions, both species recapitulate their natural burrowing behaviour. Genetic crosses between the two species reveal that the derived burrows of oldfield mice are dominant and evolved through the addition of multiple genetic changes. In burrows built by first-generation backcross mice, entrance-tunnel length and the presence of an escape tunnel can be uncoupled, suggesting that these traits are modular. Quantitative trait locus analysis also indicates that tunnel length segregates as a complex trait, affected by at least three independent genetic regions, whereas the presence of an escape tunnel is associated with only a single locus. Together, these results suggest that complex behaviours--in this case, a classic 'extended phenotype'--can evolve through multiple genetic changes each affecting distinct behaviour modules. PMID:23325221

  8. Effects of Fiddler Crab Burrows on Sediment Properties in the Mangrove Mudflats of Sungai Sepang, Malaysia

    PubMed Central

    Mokhtari, Mohammad; Abd Ghaffar, Mazlan; Usup, Gires; Che Cob, Zaidi

    2016-01-01

    In mangrove ecosystems, litter fall accumulates as refractory organic carbon on the sediment surface and creates anoxic sediment layers. Fiddler crabs, through their burrowing activity, translocate oxygen into the anoxic layers and promote aerobic respiration, iron reduction and nitrification. In this study, the effects of four species of fiddler crabs (Uca triangularis, Uca rosea, Uca forcipata and Uca paradussumieri) on organic content, water content, porosity, redox potential and solid phase iron pools of mangrove sediments were investigated. In each crab’s habitat, six cores down to 30 cm depth were taken from burrowed and non-burrowed sampling plots. Redox potential and oxidized iron pools were highest in surface sediment, while porosity, water and organic content were higher in deeper sediment. Reduced iron (Fe (II)) and redox potential were significantly different between burrowed and non-burrowed plots. Crab burrows extend the oxidized surface layer down to 4 cm depth and through the oxidation effect, reduce the organic content of sediments. The effects of burrows varied between the four species based on their shore location. The oxidation effect of burrows enhance the decomposition rate and stimulate iron reduction, which are processes that are expected to play an important role in biogeochemical properties of mangrove sediments. PMID:26797647

  9. The vibrational signals that male fiddler crabs ( Uca lactea) use to attract females into their burrows

    NASA Astrophysics Data System (ADS)

    Takeshita, Fumio; Murai, Minoru

    2016-06-01

    In some fiddler crab species, males emit vibrations from their burrows to mate-searching females after they have attracted a female to the burrow entrance using a waving display. Although the vibrations are considered acoustic signals to induce mating, it has not been demonstrated whether the vibrations attract the females into the burrow and, consequently, influence females' mating decisions. We investigated the structures and patterns of the vibrations using a dummy female and demonstrated experimentally a female preference for male vibrations in Uca lactea in the field. The acoustic signals consisted of repetitions of pulses. The dominant frequency of the pulses decreased with male carapace width. The pulse length decreased slightly with an increasing number of vibrational repetitions, and the pulse interval increased with increasing repetitions. These factors imply that the vibrations convey information on male characteristics, such as body size and stamina. In the experiment on female mate choice, the females significantly preferred males with higher pulse repetition rates when they were positioned at the entrance of the burrow, indicating that the females use the male vibrational signals to decide whether to enter the burrow. However, females showed no preference for the vibrations once they were inside a burrow, i.e., whether they decided to copulate, suggesting that the vibrations do not independently affect a female's final decision of mate choice. The vibrations inside the burrow might influence a female's decision by interaction with other male traits such as the burrow structure.

  10. Effects of Fiddler Crab Burrows on Sediment Properties in the Mangrove Mudflats of Sungai Sepang, Malaysia.

    PubMed

    Mokhtari, Mohammad; Abd Ghaffar, Mazlan; Usup, Gires; Che Cob, Zaidi

    2016-01-01

    In mangrove ecosystems, litter fall accumulates as refractory organic carbon on the sediment surface and creates anoxic sediment layers. Fiddler crabs, through their burrowing activity, translocate oxygen into the anoxic layers and promote aerobic respiration, iron reduction and nitrification. In this study, the effects of four species of fiddler crabs (Uca triangularis, Uca rosea, Uca forcipata and Uca paradussumieri) on organic content, water content, porosity, redox potential and solid phase iron pools of mangrove sediments were investigated. In each crab's habitat, six cores down to 30 cm depth were taken from burrowed and non-burrowed sampling plots. Redox potential and oxidized iron pools were highest in surface sediment, while porosity, water and organic content were higher in deeper sediment. Reduced iron (Fe (II)) and redox potential were significantly different between burrowed and non-burrowed plots. Crab burrows extend the oxidized surface layer down to 4 cm depth and through the oxidation effect, reduce the organic content of sediments. The effects of burrows varied between the four species based on their shore location. The oxidation effect of burrows enhance the decomposition rate and stimulate iron reduction, which are processes that are expected to play an important role in biogeochemical properties of mangrove sediments. PMID:26797647

  11. ENHANCED ORGANIC MATTER REMINERALIZATION AND NUTRIENT TURNOVER BY BURROWING SHRIMP POPULATIONS IN YAQUINA BAY, OR

    EPA Science Inventory

    Burrowing thalassinid shrimp are major ecological components of Pacific Northwest (PNW) estuaries and where they structure large areas of intertidal and shallow subtidal habitat. These crustaceans occur in dense beds (>250 m-2) and dig extensive burrow systems (>1 m) controlling ...

  12. The vibrational signals that male fiddler crabs (Uca lactea) use to attract females into their burrows.

    PubMed

    Takeshita, Fumio; Murai, Minoru

    2016-06-01

    In some fiddler crab species, males emit vibrations from their burrows to mate-searching females after they have attracted a female to the burrow entrance using a waving display. Although the vibrations are considered acoustic signals to induce mating, it has not been demonstrated whether the vibrations attract the females into the burrow and, consequently, influence females' mating decisions. We investigated the structures and patterns of the vibrations using a dummy female and demonstrated experimentally a female preference for male vibrations in Uca lactea in the field. The acoustic signals consisted of repetitions of pulses. The dominant frequency of the pulses decreased with male carapace width. The pulse length decreased slightly with an increasing number of vibrational repetitions, and the pulse interval increased with increasing repetitions. These factors imply that the vibrations convey information on male characteristics, such as body size and stamina. In the experiment on female mate choice, the females significantly preferred males with higher pulse repetition rates when they were positioned at the entrance of the burrow, indicating that the females use the male vibrational signals to decide whether to enter the burrow. However, females showed no preference for the vibrations once they were inside a burrow, i.e., whether they decided to copulate, suggesting that the vibrations do not independently affect a female's final decision of mate choice. The vibrations inside the burrow might influence a female's decision by interaction with other male traits such as the burrow structure. PMID:27240863

  13. Intraspecific variation in reproductive traits of burrowing owls

    USGS Publications Warehouse

    Conway, Meaghan; Nadeau, Christopher P.; Conway, Courtney J.

    2012-01-01

    Reviews of hatching asynchrony in birds recommended more studies on intraspecific variation in the extent of hatching asynchrony. We examined intraspecific variation in clutch size, laying chronology, onset of incubation, incubation period, and hatching asynchrony in burrowing owls (Athene cunicularia) in the Imperial Valley of California. Mean clutch size was 7.4 eggs and owls averaged 0.5 eggs laid per day. Females varied considerably in laying interval and onset of incubation (range = 1st to 9th egg in the clutch). The mean incubation period was 21.9 days. Hatching interval also varied greatly among females (x = 0.8, range 0.1-2.0 days between successively hatched eggs). Past burrowing owl studies have largely overlooked the substantial intraspecific variation in these traits or have reported estimates that differ from ours. Future studies designed to identify the environmental factors that explain the large intraspecific variation in these traits will likely provide insights into the constraints on local abundance.

  14. Blood characteristics, tracheal volume and heart mass of burrowing owls (Athene cunicularia) and bobwhite (Colinus virginianus).

    PubMed

    Boggs, D F; Birchard, G F; Kilgore, D L

    1983-01-01

    1. Measurements of certain hematological and morphological characteristics were made in burrowing owls and bobwhite in search of features that could be associated with the previously described ventilatory adaptations of the burrowing owl to hypoxia and hypercarbia. 2. Values for burrowing owls and bobwhite, respectively, were: P50 = 44.9, 46.0 torr; Hct = 36.6, 38.8 vol%, Hb = 12, 12.3 (g/100 ml); RBC = 2.72 X 10(6), 3.02 X 10(6); log P50/pH = -0.412, -0.485; delta log PCO2/delta pH = -1.39, -1.585. 3. The owls had greater heart weights and smaller tracheal volumes than the bobwhite or the predicted value. 4. No hematological characteristics of the burrowing bird distinguish it from the non-burrowing bird. PMID:6132713

  15. Vertical distribution of soil removed by four species of burrowing rodents in disturbed and undisturbed soils

    SciTech Connect

    Reynolds, T.D.; Laundre, J.W.

    1988-04-01

    Burrow volumes were determined in disturbed and undisturbed soils for four species of rodents in southeastern Idaho. Comparisons were made between soil types for the average volume and the proportion of the total volume of soil excavated from 10-cm increments for each species, and the relative number of burrows and proportion of total soil removed from beneath the minimum thickness of soil covers over buried low-level radioactive wastes. Burrows of montane voles (Microtus montanus) and deer mice (Peromyscus maniculatus) rarely extended below 50 cm and neither volumes nor depths were influenced by soil disturbance. Townsend's ground squirrels (Spermophilus townsendii) had the deepest and most voluminous burrows that, along with Ord's kangaroo rat (Dipodomys ordii) burrows, were more prevalent beneath 50 cm in disturbed soils.

  16. Land crabs as key drivers in tropical coastal forest recruitment

    USGS Publications Warehouse

    Lindquist, E.S.; Krauss, K.W.; Green, P.T.; O'Dowd, D. J.; Sherman, P.M.; Smith, T. J., III

    2009-01-01

    Plant populations are regulated by a diverse assortment of abiotic and biotic factors that influence seed dispersal and viability, and seedling establishment and growth at the microsite. Rarely does one animal guild exert as significant an influence on different plant assemblages as land crabs. We review three tropical coastal ecosystems-mangroves, island maritime forests, and mainland coastal terrestrial forests-where land crabs directly influence forest composition by limiting tree establishment and recruitment. Land crabs differentially prey on seeds, propagules and seedlings along nutrient, chemical and physical environmental gradients. In all of these ecosystems, but especially mangroves, abiotic gradients are well studied, strong and influence plant species distributions. However, we suggest that crab predation has primacy over many of these environmental factors by acting as the first limiting factor of tropical tree recruitment to drive the potential structural and compositional organisation of coastal forests. We show that the influence of crabs varies relative to tidal gradient, shoreline distance, canopy position, time, season, tree species and fruiting periodicity. Crabs also facilitate forest growth and development through such activities as excavation of burrows, creation of soil mounds, aeration of soils, removal of leaf litter into burrows and creation of carbon-rich soil microhabitats. For all three systems, land crabs influence the distribution, density and size-class structure of tree populations. Indeed, crabs are among the major drivers of tree recruitment in tropical coastal forest ecosystems, and their conservation should be included in management plans of these forests. ?? 2009 Cambridge Philosophical Society.

  17. River bank burrowing by invasive crayfish: Spatial distribution, biophysical controls and biogeomorphic significance.

    PubMed

    Faller, Matej; Harvey, Gemma L; Henshaw, Alexander J; Bertoldi, Walter; Bruno, Maria Cristina; England, Judy

    2016-11-01

    Invasive species generate significant global environmental and economic costs and represent a particularly potent threat to freshwater systems. The biogeomorphic impacts of invasive aquatic and riparian species on river processes and landforms remain largely unquantified, but have the potential to generate significant sediment management issues within invaded catchments. Several species of invasive (non-native) crayfish are known to burrow into river banks and visual evidence of river bank damage is generating public concern and media attention. Despite this, there is a paucity of understanding of burrow distribution, biophysical controls and the potential significance of this problem beyond a small number of local studies at heavily impacted sites. This paper presents the first multi-catchment analysis of this phenomenon, combining existing data on biophysical river properties and invasive crayfish observations with purpose-designed field surveys across 103 river reaches to derive key trends. Crayfish burrows were observed on the majority of reaches, but burrowing tended to be patchy in spatial distribution, concentrated in a small proportion (<10%) of the length of rivers surveyed. Burrow distribution was better explained by local bank biophysical properties than by reach-scale properties, and burrowed banks were more likely to be characterised by cohesive bank material, steeper bank profiles with large areas of bare bank face, often on outer bend locations. Burrow excavation alone has delivered a considerable amount of sediment to invaded river systems in the surveyed sites (3tkm(-1) impacted bank) and this represents a minimum contribution and certainly an underestimate of the absolute yield (submerged burrows were not recorded). Furthermore, burrowing was associated with bank profiles that were either actively eroding or exposed to fluvial action and/or mass failure processes, providing the first quantitative evidence that invasive crayfish may cause or

  18. Spilled oil and infaunal activity - Modification of burrowing behavior and redistribution of oil

    USGS Publications Warehouse

    Clifton, H.E.; Kvenvolden, K.A.; Rapp, J.B.

    1984-01-01

    A series of experiments in Willapa Bay, Washington, indicates the degree to which the presence of spilled oil modifies the burrowing behavior of infauna and the extent to which the animals redistribute oil into intertidal sediment. Small amounts of North Slope crude oil introduced at low tide directly into burrow openings (mostly made by the crustacean Callianassa) resulted in a limited and temporary reduction in the number of burrow openings. In contrast, a layer of oil-saturated sand 1 cm thick buried about 5 cm below the sediment surface sharply reduced the number of burrow openings. After a year, the few new burrows penetrated only the margins of the experimental plot, and bioturbation below the buried oil-saturated sand layer declined dramatically. The experiments suggest that small amounts of oil temporarily stranded by tides in themselves have no long-range effect on burrowing behavior. The fauna, however, are capable of introducing measurable amounts of oil into the subsurface, where it is retained long after the rest of the stranded oil had washed away. A buried layer of oil-saturated sand greatly reduces infaunal activity; the oil presents an effective barrier that can persist for years. The oil incorporated into the sediment from burrow openings showed evidence of degradation after 7 months. In contrast the layer of buried oil remained essentially undergraded after a period of two years, even though oil in lower concentrations above the layer was degraded after a period of one year. This variation in degree of degradation of the buried oil, as well as the heterogeneity of oil distribution wherever the oil has been incorporated from the surface, emphasises the importance of careful sampling in any attempt to locate or monitor the presence of spilled oil in the substrate.In a series of experiments in Willapa Bay, Washington, small amounts of North Slope crude oil introduced at low tide directly into burrow openings resulted in a limited and temporary

  19. Burrow morphology of Uca uruguayensis and Uca leptodactylus (Decapoda: Ocypodidae) from a subtropical mangrove forest in the western Atlantic.

    PubMed

    Machado, Glauco B O; Gusmão-Junior, João B L; Costa, Tânia M

    2013-09-01

    The continuous excavation of burrows by fiddler crabs generates bioturbation in the sediment, which can be estimated from burrow morphology. The aim of the present study was to describe the burrow morphology of Uca uruguayensis and U. leptodactylus and its relationship with demography of resident individuals and to estimate the level of bioturbation in the sediment generated by each species. For all individuals from each of the 2 species, sex was determined and the carapace width (CW; mm) measured. Burrows were characterized according to burrow diameter (BD; mm), maximum burrow depth (MBD; mm) and burrow volume (BV; cm(3) ). The density of each species in the study area was also evaluated. In both species, the males were larger and occupied burrows with higher BV compared to females. Differences between sexes in relation to the burrow characteristics might reflect sexual dimorphism within the group and are probably related to the fact that males use the burrows for mating. BD and BV showed significant positive relationships with the size of resident crabs. The amount of sediment removed per burrow was estimated from mean BV: 10.78 cm(3) of sediment/burrow for U. uruguayensis and 12.38 cm(3) of sediment/burrow for U. leptodactylus. Despite the density and depth differences between the 2 species, the similarity in burrow volume suggests that U. uruguayensis and U. leptodactylus present the same importance in terms of the bioturbation process. Burrow morphology is highly associated with characteristics of the occupant, although extrinsic factors should also be considered, and its description can provide estimates on the bioturbation generated by Uca species in mangrove forests. PMID:24020469

  20. Self-burrowing seeds: drag reduction in granular media

    NASA Astrophysics Data System (ADS)

    Jung, Wonjong; Choi, Sung Mok; Kim, Wonjung; Kim, Ho-Young

    2014-11-01

    We present the results of a combined experimental and theoretical investigation of drag reduction of self-burrowing seeds in granular media. In response to environmental changes in humidity, the awn (a tail-like appendage of seed) of Pelargonium carnosum exhibits coiling-uncoiling deformation which induces the thrust and rotary motions of the head of the seed against the surface of the soil. Using various sizes of glass beads that mimic the granular soil, we measure the thrust forces required for the seed of Pelargonium carnosum to penetrate into granular media with and without rotation. Our quantitative measurements show that the rotation of the seed remarkably reduces the granular drag as compared to the drag against the non-spinning seed. This leads us to conclude that the hygroscopically active awns of Pelargonium carnosum enables its seed to dig into the relatively coarse granular soils.

  1. Blood oxygen binding properties for the burrowing owl, Athene cunicularia.

    PubMed

    Maginniss, L A; Kilgore, D L

    1989-05-01

    Isocapnic O2 equilibrium curves (O2ECs) were generated for whole blood of 4 adult burrowing owls (Athene cunicularia) using thin film techniques. At in vivo pHa (7.49 +/- 0.02; mean +/- 1 SEM) and 41 degrees C, the PO2 at half saturation (P50) was 42.3 +/- 0.8 Torr. CO2 and fixed acid (H+) Bohr slopes (delta log P50/delta pH) were -0.46 +/- 0.01 and -0.42 +/- 0.02, respectively, demonstrating a small specific CO2 effect. CO2 and H+ Bohr slopes were saturation-independent between 0.1 and 0.9 S. Hill plots for Athene blood were non-linear; the Hill coefficient (n) increased from 2.6 below 0.4 S to 3.4 above 0.6 S. Owl equilibrium data were accurately described by the equation: S = [(7.7 x 10(6]/(P4 + 44P3 - 108P2 + 3.5 x 10(4)P) + 1]-1. This complex O2EC shape may result from Hb heterogeneity; isoelectric focusing showed 4 isoHbs with a molar ratio of 9:1:1:1. This study revealed no apparent adaptations of Athene blood for hypoxic and hypercapnic conditions. We conclude that the observed blood O2 binding properties promote tissue O2 delivery during periods of surface activity. While occupying its burrow, the owl compensates for moderate alterations in inspired gas composition partly through increased ventilation. PMID:2749025

  2. Burrowing mayflies (Hexagenia) as indicators of ecosystem health

    USGS Publications Warehouse

    Edsall, Thomas A.

    2001-01-01

    Three State of the Lakes Ecosystem Conferences have been held since 1996 to encourage the development of Great Lakes indicators of ecosystem health for use in reporting on progress in restoring and maintaining the chemical, physical and biological integrity of the Great Lakes ecosystem. Here we report on the development of an indicator based on burrowing mayflies, Hexagenia (Ephemeroptera: Ephemeridae), using production and biomass as the indicator metrics. Burrowing mayflies were selected because they (1) were historically abundant in unpolluted, soft-bottomed mesotrophic habitats throughout the Great Lakes, (2) are intolerant of and were extirpated by pollution in most of those habitats during the 1940s to 1950s, (3) have shown the ability to recover in one of those habitats following pollution abatement, (4) are ecologically important as bioturbators of lakebed sediments and as trophic integrators that link detrital energy resources directly to fishes that feed preferentially on them, and (5) have highly visible mating flights, which carry the message directly to an informed public that the source water body is healthy. In addition, their annual production can be estimated from their mean annual biomass by the size-frequency method. Productivity and biomass can also be estimated with a 'cohort-direct' method, using the biomass of mature nymphs collected in May or early June from the cohort that is about to emerge as subimagos in late June or early July. Although both the size-frequency and cohort-direct methods provide reliable estimates of productivity and biomass, the latter method greatly reduces sample collection and processing effort and thus makes it feasible to use Hexagenia as an indicator of ecosystem health in surveys requiring the collection of large numbers of samples.

  3. Burrowing and huddling in newborn porcupine: the effect on thermoregulation.

    PubMed

    Haim, A; Van Aarde, R J; Skinner, J D

    1992-08-01

    The newborn cape porcupine Hystrix africaeaustralis is a precocial rodent. However, the newborn spends its first 9 weeks in the burrow. Heat production (oxygen consumption--VO2) and body temperature (Tb) were measured at various ambient temperatures (Ta) in newborn (4-8-week-old) porcupines, with a body mass between 1340-1993 g during summer, from the colony kept at the Mammal Research Institute, University of Pretoria. To assess the effect of huddling, these parameters were also measured in adult pairs of porcupines (Ta = 15 and 25 degrees C) kept together in the metabolic chamber and the values were compared with those obtained from single porcupines. Overall minimal thermal conductance was calculated for newborn and paired adult porcupines. The newborn porcupines can regulate their body temperature at Tas between 10-28 degrees C. VO2 measured at lower critical point is 0.602 +/- 0.08 ml/O2/g.h. At Ta = 10 degrees C, VO2 oscillated with a characteristic amplitude and frequency, while body temperature was well regulated. Huddling decreases the lower critical point. The overall minimal thermal conductance (0.044 +/- 0.002 ml O2/g.h.1 degree C) is higher than expected from body mass, so that the young are liable to lose heat rapidly. It is well known that the newborn porcupine spends a long period in the burrow and the results of this study suggest that this may be in order to conserve energy and presumably allocate it to growth. Apart from decreasing vulnerability, delaying foraging also avoids heat loss in the newborn porcupine. PMID:1523249

  4. First trace and body fossil evidence of a burrowing, denning dinosaur

    PubMed Central

    Varricchio, David J; Martin, Anthony J; Katsura, Yoshihiro

    2007-01-01

    A fossil discovery in the mid-Cretaceous Blackleaf Formation of southwest Montana, USA, has yielded the first trace and body fossil evidence of burrowing behaviour in a dinosaur. Skeletal remains of an adult and two juveniles of Oryctodromeus cubicularis gen. et sp. nov., a new species of hypsilophodont-grade dinosaur, were found in the expanded distal chamber of a sediment-filled burrow. Correspondence between burrow and adult dimensions supports Oryctodromeus as the burrow maker. Additionally, Oryctodromeus exhibits features of the snout, shoulder girdle and pelvis consistent with digging habits while retaining cursorial hindlimb proportions. Association of adult and young within a terminal chamber provides definitive evidence of extensive parental care in the Dinosauria. As with modern vertebrate cursors that dig, burrowing in Oryctodromeus may have been an important adaptation for the rearing of young. Burrowing also represents a mechanism by which small dinosaurs may have exploited the extreme environments of polar latitudes, deserts and high mountain areas. The ability among dinosaurs to find or make shelter may contradict some scenarios of the Cretaceous–Paleogene impact event. Burrowing habits expand the known range of nonavian dinosaur behaviours and suggest that the cursorial ancestry of dinosaurs did not fully preclude the evolution of different functional regimes, such as fossoriality. PMID:17374596

  5. Use of burrow entrances to indicate densities of Townsend's ground squirrels

    USGS Publications Warehouse

    Van Horne, Beatrice; Schooley, R.L.; Knick, Steven T.; Olson, G.S.; Burnham, K.P.

    1997-01-01

    Counts of burrow entrances have been positively correlated with densities of semi-fossorial rodents and used as an index of densities. We evaluated their effectiveness in indexing densities of Townsend's ground squirrels (Spermophilus townsendii) in the Snake River Birds of Prey National Conservation Area (SRBOPNCA), Idaho, by comparing burrow entrance densities to densities of ground squirrels estimated from livetrapping in 2 consecutive years over which squirrel populations declined by >75%. We did not detect a consistent relation between burrow entrance counts and ground squirrel density estimates within or among habitat types. Scatter plots indicated that burrow entrances had little predictive power at intermediate densities. Burrow entrance counts did not reflect the magnitude of a between-year density decline. Repeated counts of entrances late in the squirrels' active season varied in a manner that would be difficult to use for calibration of transects sampled only once during this period. Annual persistence of burrow entrances varied between habitats. Trained observers were inconsistent in assigning active-inactive status to entrances. We recommend that burrow entrance counts not be used as measures or indices of ground squirrel densities in shrubsteppe habitats, and that the method be verified thoroughly before being used in other habitats.

  6. Lungfish burrows in the Upper Triassic Chinle and Dolores Formations, Colorado Plateau ( USA).

    USGS Publications Warehouse

    Dubiel, R.F.; Blodgett, R.H.; Bown, T.M.

    1987-01-01

    Vertical-to-inclined, cylindrical trace fossils that occur in the Upper Triassic Chinle and Dolores Formations on the Colorado Plateau are interpreted to be the casts of lungfish burrows based on their morphologic similarity to previously identified lungfish burrows. The casts were formed by passive siliciclastic and carbonate sedimentation into apparently abandoned lungfish burrows. Locally, the burrow fillings are overwhelmingly abundant, and many intersect and have destroyed former burrow fillings. Bioturbation has contributed to the mottled coloration and the knobby-weathering texture of the rocks. The burrow-fillings occur ubiquitously in three lithofacies, deposited in a continental environment that included fluvial channels and floodplains, sand sheets and playa mudflats, and lacustrine basins, marshes, and deltas. The widespread occurrence of the lungfish burrows in the Chinle and Dolores Formations attests to the extensive habitat that supported lungfish in the Late Triassic. Analogy with the environments that support modern lungfish populations suggests that the Late Triassic climate in the study area provided sufficient moisture to support large populations of lungfish and that this climate was probably punctuated by seasonally dry periods. -from Authors

  7. It's tough to be small: dependence of burrowing kinematics on body size.

    PubMed

    Che, James; Dorgan, Kelly M

    2010-04-01

    Burrowing marine infauna are morphologically diverse and range in size over several orders of magnitude. Whilst effects of ontogenetic and morphological differences on running, flying and swimming are relatively well understood, similar analyses of burrowing mechanics and kinematics are lacking. The polychaete Nereis virens Sars extends its burrow by fracture, using an eversible pharynx to exert force on the walls of the burrow. The resulting stress is amplified at the anterior tip of the burrow, which extends when the stress exceeds the fracture toughness of the material. Here we show that the polychaete Cirriformia moorei extends its burrow by a similar mechanism, but by using its hydrostatic skeleton rather than an eversible pharynx. Based on the dimensionless wedge number, which relates work of fracture to work to maintain body shape against the elasticity of sediment, we predicted that smaller worms would exhibit behaviors characteristic of tougher sediments and that scaling of kinematics would reflect decreasing difficulty in fracturing sediment with increasing body size. We found that smaller worms were relatively blunter and thicker, and had a greater variation of thickness than larger worms as they burrowed. Although these kinematic differences increase the stress amplification at the crack tip, smaller worms still generate lower stress intensity factors. The greater relative body thickness and shape changes of smaller worms are consistent with ontogenetic changes in forces exerted by earthworms, and are likely driven by the challenge of exerting enough stress to extend a crack with a small body size. PMID:20348335

  8. The influence of small mammal burrowing activity on water storage at the Hanford Site

    SciTech Connect

    Landeen, D.S.

    1994-09-01

    The amount and rate at which water may penetrate a protective barrier and come into contact with buried radioactive waste is a major concern. Because burrowing animals eventually will reside on the surface of any protective barrier, the effect these burrow systems may have on the loss or retention of water needs to be determined. The first section of this document summarizes the known literature relative to small mammals and the effects that burrowing activities have on water distribution, infiltration, and the overall impact of burrows on the ecosystem. Topics that are summarized include burrow air pressures, airflow, burrow humidity, microtopography, mounding, infiltration, climate, soil evaporation, and discussions of large pores relative to water distribution. The second section of this document provides the results of the study that was conducted at the Hanford Site to determine what effect small mammal burrows have on water storage. This Biointrusion task is identified in the Permanent Isolation Surface Barrier Development Plan in support of protective barriers. This particular animal intrusion task is one part of the overall animal intrusion task identified in Animal Intrusion Test Plan.

  9. Amplification and spectral shifts of vocalizations inside burrows of the frog Eupsophus calcaratus (Leptodactylidae)

    NASA Astrophysics Data System (ADS)

    Penna, Mario

    2004-08-01

    A variety of animals that communicate by sound emit signals from sites favoring their propagation, thereby increasing the range over which these sounds convey information. A different significance of calling sites has been reported for burrowing frogs Eupsophus emiliopugini from southern Chile: the cavities from which these frogs vocalize amplify conspecific vocalizations generated externally, thus providing a means to enhance the reception of neighbor's vocalizations in chorusing aggregations. In the current study the amplification of vocalizations of a related species, E. calcaratus, is investigated, to explore the extent of sound enhancement reported previously. Advertisement calls broadcast through a loudspeaker placed in the vicinity of a burrow, monitored with small microphones, are amplified by up to 18 dB inside cavities relative to outside. The fundamental resonant frequency of burrows, measured with broadcast noise and pure tones, ranges from 842 to 1836 Hz and is significantly correlated with the burrow's length. Burrows change the spectral envelope of incoming calls by increasing the amplitude of lower relative to higher harmonics. The call amplification effect inside burrows of E. calcaratus parallels the effect reported previously for E. emiliopugini, and indicates that the acoustic properties of calling sites may affect signal reception by burrowing animals.

  10. Large-Diameter Burrows of the Triassic Ischigualasto Basin, NW Argentina: Paleoecological and Paleoenvironmental Implications

    PubMed Central

    Colombi, Carina E.; Fernández, Eliana; Currie, Brian S.; Alcober, Oscar A.; Martínez, Ricardo; Correa, Gustavo

    2012-01-01

    Large-diameter ichnofossils comprising three morphotypes have been identified in the Upper Triassic Ischigualasto and Los Colorados formations of northwestern Argentina. These burrows add to the global record of the early appearance of fossorial behavior during early Mesozoic time. Morphotypes 1 and 2 are characterized by a network of tunnels and shafts that can be assigned to tetrapod burrows given similarities with previously described forms. However, differences in diameter, overall morphology, and stratigraphic occurrence allow their independent classification. Morphotype 3 forms a complex network of straight branches that intersect at oblique angles. Their calcareous composition and surface morphology indicate these structures have a composite biogenic origin likely developed due to combined plant/animal interactions. The association of Morphotypes 1 and 2 with fluvial overbank lithologies deposited under an extremely seasonal arid climate confirms interpretations that the early appearance of burrowing behavior was employed by vertebrates in response to both temperature and moisture-stress associated with seasonally or perpetually dry Pangean paleoclimates. Comparisons of burrow morphology and biomechanical attributes of the abundant paleovertebrate fauna preserved in both formations permit interpretations regarding the possible burrow architects for Morphotypes 1 and 2. In the case of the Morphotype 1, the burrow constructor could be one of the small carnivorous cynodonts, Ecteninion or Probelesodon. Assigning an architect for Morphotype 2 is more problematic due to mismatches between the observed burrow morphology and the size of the known Los Colorados vertebrates. PMID:23227195

  11. Polychaete burrows harbour distinct microbial communities in oil-contaminated coastal sediments.

    PubMed

    Taylor, Joe D; Cunliffe, Michael

    2015-08-01

    Previous studies have shown that the bioturbating polychaete Hediste (Nereis) diversicolor can affect the composition of bacterial communities in oil-contaminated sediments, but have not considered diversity specifically within bioturbator burrows or the impact on microbial eukaryotes. We tested the hypothesis that H. diversicolor burrows harbour different eukaryotic and bacterial communities compared with un-bioturbated sediment, and that bioturbation stimulates oil degradation. Oil-contaminated sediment was incubated with or without H. diversicolor for 30 days, after which sediment un-affected by H. diversicolor and burrow DNA/RNA samples were analysed using quantitative reverse transcription PCR (Q-RT-PCR) and high-throughput sequencing. Fungi dominated both burrow and un-bioturbated sediment sequence libraries; however, there was significant enrichment of bacterivorous protists and nematodes in the burrows. There were also significant differences between the bacterial communities in burrows compared with un-bioturbated sediment. Increased activity and relative abundance of aerobic hydrocarbon-degrading bacteria in the burrows coincided with the significant reduction in hydrocarbon concentration in the bioturbated sediment. This study represents the first detailed assessment of the effect of bioturbation on total microbial communities in oil-contaminated sediments. In addition, it further shows that bioturbation is a significant factor in determining microbial diversity within polluted sediments and plays an important role in stimulating bioremediation. PMID:25858418

  12. Spatial organization of desert tortoises and their burrows at a landscape scale

    USGS Publications Warehouse

    Duda, Jeffrey J.; Krzysik, Anthony J.; Meloche, Joel M.

    2001-01-01

    We thoroughly surveyed two 9 km 2 study plots using 624 km of transect lines in the south- central Mojave Desert, California, mapping with a precision global positioning system the location of desert tortoises (Gopherus agassizii) and their burrows. We found 98 desert tortoises and 1463 tortoise burrows. Three separate geospatial methods (quadrat-variance, nearest neighbor, and 3 geospatial functions) confirmed that active and total desert tortoise burrows were aggregated on the landscape at multiple spatial scales. Desert tortoises also displayed an aggregated pattern, although results were not consistent between the two plots. We also found a significant positive association between desert tortoises and their burrows using Type II linear regression and Ripley's K 12(t) function. A strong positive association between active burrows/km 2 and tortoises/km2 (r2 = 0.88) and between total burrows/km2 and tortoises/km2 (r2 = 0.80) and the supporting results of Ripley's K 12(t) geospatial function suggest that, within a given year and locality, desert tortoise burrows can be used to determine relative desert tortoise density patterns.

  13. Adjustment to Recruit Training.

    ERIC Educational Resources Information Center

    Anderson, Betty S.

    The thesis examines problems of adjustment encountered by new recruits entering the military services. Factors affecting adjustment are discussed: the recruit training staff and environment, recruit background characteristics, the military's image, the changing values and motivations of today's youth, and the recruiting process. Sources of…

  14. Similar burrow architecture of three arid-zone scorpion species implies similar ecological function.

    PubMed

    Adams, Amanda M; Marais, Eugene; Turner, J Scott; Prendini, Lorenzo; Pinshow, Berry

    2016-08-01

    Many animals reside in burrows that may serve as refuges from predators and adverse environmental conditions. Burrow design varies widely among and within taxa, and these structures are adaptive, fulfilling physiological (and other) functions. We examined the burrow architecture of three scorpion species of the family Scorpionidae: Scorpio palmatus from the Negev desert, Israel; Opistophthalmus setifrons, from the Central Highlands, Namibia; and Opistophthalmus wahlbergii from the Kalahari desert, Namibia. We hypothesized that burrow structure maintains temperature and soil moisture conditions optimal for the behavior and physiology of the scorpion. Casts of burrows, poured in situ with molten aluminum, were scanned in 3D to quantify burrow structure. Three architectural features were common to the burrows of all species: (1) a horizontal platform near the ground surface, long enough to accommodate the scorpion, located just below the entrance, 2-5 cm under the surface, which may provide a safe place where the scorpion can monitor the presence of potential prey, predators, and mates and where the scorpion warms up before foraging; (2) at least two bends that might deter incursion by predators and may reduce convective ventilation, thereby maintaining relatively high humidity and low temperature; and (3) an enlarged terminal chamber to a depth at which temperatures are almost constant (±2-4 °C). These common features among the burrows of three different species suggest that they are important for regulating the physical environment of their inhabitants and that burrows are part of scorpions' "extended physiology" (sensu Turner, Physiol Biochem Zool 74:798-822, 2000). PMID:27312362

  15. Chemically mediated burrow recognition in the Mexican tarantula Brachypelma vagans female

    NASA Astrophysics Data System (ADS)

    Dor, Ariane; Machkour-M'rabet, Salima; Legal, Luc; Williams, Trevor; Hénaut, Yann

    2008-12-01

    Chemically mediated communication is common in spiders but has been poorly studied in burrowing tarantulas. This study aimed to determine whether chemical cues influence the behaviour of females of Brachypelma vagans, a Mexican species of tarantula, during encounters with previously inhabited burrows or with extracts from the silk of conspecific females. In laboratory choice tests, female tarantulas entered a burrow that had previously been inhabited by a conspecific female significantly more frequently than a burrow that had never been inhabited. The identity of the previous inhabitant also affected the number of spiders that chose to enter a burrow. Spiders were quicker to choose and enter a burrow previously inhabited by themselves than a burrow previously inhabited by a conspecific or a burrow that had not been previously inhabited. Hexane, methanol and dichloromethane extracts of conspecific silk elicited different responses from female tarantulas when extracts were placed on filter paper disks at one end of an experimental arena with a control filter paper disk, on to which the corresponding solvent alone had been pipetted, placed on the other end of the arena. Spiders showed the strongest responses to hexane extracts of silk, with a significant preference to move towards the hexane extract and a significantly greater period of time spent in proximity to the hexane extract compared to the control disk. Overall and in contrast to expectations, tarantulas were most strongly attracted to the cues left by other conspecific females. As encounters between B. vagans females usually lead to aggression and mortality of one of the participants, we conclude that chemical cues are not signals that are deliberately released by burrow-inhabiting females but may inadvertently escape and cannot be easily suppressed.

  16. Similar burrow architecture of three arid-zone scorpion species implies similar ecological function

    NASA Astrophysics Data System (ADS)

    Adams, Amanda M.; Marais, Eugene; Turner, J. Scott; Prendini, Lorenzo; Pinshow, Berry

    2016-08-01

    Many animals reside in burrows that may serve as refuges from predators and adverse environmental conditions. Burrow design varies widely among and within taxa, and these structures are adaptive, fulfilling physiological (and other) functions. We examined the burrow architecture of three scorpion species of the family Scorpionidae: Scorpio palmatus from the Negev desert, Israel; Opistophthalmus setifrons, from the Central Highlands, Namibia; and Opistophthalmus wahlbergii from the Kalahari desert, Namibia. We hypothesized that burrow structure maintains temperature and soil moisture conditions optimal for the behavior and physiology of the scorpion. Casts of burrows, poured in situ with molten aluminum, were scanned in 3D to quantify burrow structure. Three architectural features were common to the burrows of all species: (1) a horizontal platform near the ground surface, long enough to accommodate the scorpion, located just below the entrance, 2-5 cm under the surface, which may provide a safe place where the scorpion can monitor the presence of potential prey, predators, and mates and where the scorpion warms up before foraging; (2) at least two bends that might deter incursion by predators and may reduce convective ventilation, thereby maintaining relatively high humidity and low temperature; and (3) an enlarged terminal chamber to a depth at which temperatures are almost constant (±2-4 °C). These common features among the burrows of three different species suggest that they are important for regulating the physical environment of their inhabitants and that burrows are part of scorpions' "extended physiology" ( sensu Turner, Physiol Biochem Zool 74:798-822, 2000).

  17. Chemically mediated burrow recognition in the Mexican tarantula Brachypelma vagans female.

    PubMed

    Dor, Ariane; Machkour-M'Rabet, Salima; Legal, Luc; Williams, Trevor; Hénaut, Yann

    2008-12-01

    Chemically mediated communication is common in spiders but has been poorly studied in burrowing tarantulas. This study aimed to determine whether chemical cues influence the behaviour of females of Brachypelma vagans, a Mexican species of tarantula, during encounters with previously inhabited burrows or with extracts from the silk of conspecific females. In laboratory choice tests, female tarantulas entered a burrow that had previously been inhabited by a conspecific female significantly more frequently than a burrow that had never been inhabited. The identity of the previous inhabitant also affected the number of spiders that chose to enter a burrow. Spiders were quicker to choose and enter a burrow previously inhabited by themselves than a burrow previously inhabited by a conspecific or a burrow that had not been previously inhabited. Hexane, methanol and dichloromethane extracts of conspecific silk elicited different responses from female tarantulas when extracts were placed on filter paper disks at one end of an experimental arena with a control filter paper disk, on to which the corresponding solvent alone had been pipetted, placed on the other end of the arena. Spiders showed the strongest responses to hexane extracts of silk, with a significant preference to move towards the hexane extract and a significantly greater period of time spent in proximity to the hexane extract compared to the control disk. Overall and in contrast to expectations, tarantulas were most strongly attracted to the cues left by other conspecific females. As encounters between B. vagans females usually lead to aggression and mortality of one of the participants, we conclude that chemical cues are not signals that are deliberately released by burrow-inhabiting females but may inadvertently escape and cannot be easily suppressed. PMID:18712335

  18. Ectoparasites of Burrowing Owls (Athene cunicularia hypugaea) wintering in southern Texas

    USGS Publications Warehouse

    Skoruppa, M.K.; Pearce, B.; Woodin, M.C.; Hickman, G.C.

    2006-01-01

    Fifteen Western Burrowing Owls (Athene cunicularia hypugaea) were captured over two winters (2001-2003) in southern Texas and examined for ectoparasites. Four of the 15 owls (27%) harbored feather lice, and the maximum number of lice found on any individual was ??? three. Two species of feather lice were found: Colpocephalum pectinatum occurred on three of the owls, and Strigiphilus speotyti was found on four owls. No fleas or other ectoparasites were found on any of the Burrowing Owls. The low diversity and numbers of ectoparasites suggest that ectoparasites are not threatening the health of wintering Burrowing Owls in southern Texas.

  19. The evolution of soil-burrowing cockroaches (Blattaria: Blaberidae) from wood-burrowing ancestors following an invasion of the latter from Asia into Australia.

    PubMed

    Maekawa, Kiyoto; Lo, Nathan; Rose, Harley A; Matsumoto, Tadao

    2003-06-22

    Morphologically similar cockroaches in the subfamilies Panesthiinae and Geoscapheinae (Blattaria: Blaberidae) display contrasting feeding habits, behaviour and biogeographical distributions. Panesthiinae, found throughout Asia and Australia, all live in and feed on decaying wood that they burrow into. Geoscapheinae are restricted to Australia and construct and live in burrows in the soil, where they feed on dry leaves taken from the surface. A lack of knowledge about phylogenetic relationships among these cockroaches hinders an understanding of the factors that have shaped the evolution of their diverse lifestyles and biogeography. To address this issue, we sequenced three genes from representatives of nine of the 10 genera in the two subfamilies, and performed phylogenetic analyses. The well-supported topology revealed the Panesthiinae to be paraphyletic with respect to the Geoscapheinae. Soil-burrowing cockroaches appear to have evolved from a lineage of wood burrowers that invaded Australia from the north some time after the merging of the Asian and Australian tectonic plates ca. 20 Myr ago. The main factor promoting the evolution of soil burrowing is likely to have been one of the periods of strong aridity that Australia has experienced since the Miocene period. PMID:12816644

  20. The evolution of soil-burrowing cockroaches (Blattaria: Blaberidae) from wood-burrowing ancestors following an invasion of the latter from Asia into Australia.

    PubMed Central

    Maekawa, Kiyoto; Lo, Nathan; Rose, Harley A.; Matsumoto, Tadao

    2003-01-01

    Morphologically similar cockroaches in the subfamilies Panesthiinae and Geoscapheinae (Blattaria: Blaberidae) display contrasting feeding habits, behaviour and biogeographical distributions. Panesthiinae, found throughout Asia and Australia, all live in and feed on decaying wood that they burrow into. Geoscapheinae are restricted to Australia and construct and live in burrows in the soil, where they feed on dry leaves taken from the surface. A lack of knowledge about phylogenetic relationships among these cockroaches hinders an understanding of the factors that have shaped the evolution of their diverse lifestyles and biogeography. To address this issue, we sequenced three genes from representatives of nine of the 10 genera in the two subfamilies, and performed phylogenetic analyses. The well-supported topology revealed the Panesthiinae to be paraphyletic with respect to the Geoscapheinae. Soil-burrowing cockroaches appear to have evolved from a lineage of wood burrowers that invaded Australia from the north some time after the merging of the Asian and Australian tectonic plates ca. 20 Myr ago. The main factor promoting the evolution of soil burrowing is likely to have been one of the periods of strong aridity that Australia has experienced since the Miocene period. PMID:12816644

  1. Determinants of between-year burrow re-occupation in a colony of the European bee-eater Merops apiaster.

    PubMed

    Brust, Vera; Bastian, Hans-Valentin; Bastian, Anita; Schmoll, Tim

    2015-08-01

    Re-occupation of existing nesting burrows in the European bee-eater Merops apiaster has only rarely - and if so mostly anecdotically - been documented in the literature record, although such behavior would substantially save time and energy. In this study, we quantify burrow re-occupation in a German colony over a period of eleven years and identify ecological variables determining reuse probability. Of 179 recorded broods, 54% took place in a reused burrow and the overall probability that one of 75 individually recognized burrows would be reused in a given subsequent year was estimated as 26.4%. This indicates that between-year burrow reuse is a common behavior in the study colony which contrasts with findings from studies in other colonies. Furthermore, burrow re-occupation probability declined highly significantly with increasing age of the breeding wall. Statistical separation of within- and between-burrow effects of the age of the breeding wall revealed that a decline in re-occupation probability with individual burrow age was responsible for this and not a selective disappearance of burrows with high re-occupation probability over time. Limited duty cycles of individual burrows may be caused by accumulating detritus or decreasing stability with increasing burrow age. Alternatively, burrow fidelity may presuppose pair fidelity which may also explain the observed restricted burrow reuse duty cycles. A consequent next step would be to extend our within-colony approach to other colonies and compare the ecological circumstances under which bee-eaters reuse breeding burrows. PMID:26355473

  2. Determinants of between-year burrow re-occupation in a colony of the European bee-eater Merops apiaster

    PubMed Central

    Brust, Vera; Bastian, Hans-Valentin; Bastian, Anita; Schmoll, Tim

    2015-01-01

    Re-occupation of existing nesting burrows in the European bee-eater Merops apiaster has only rarely – and if so mostly anecdotically – been documented in the literature record, although such behavior would substantially save time and energy. In this study, we quantify burrow re-occupation in a German colony over a period of eleven years and identify ecological variables determining reuse probability. Of 179 recorded broods, 54% took place in a reused burrow and the overall probability that one of 75 individually recognized burrows would be reused in a given subsequent year was estimated as 26.4%. This indicates that between-year burrow reuse is a common behavior in the study colony which contrasts with findings from studies in other colonies. Furthermore, burrow re-occupation probability declined highly significantly with increasing age of the breeding wall. Statistical separation of within- and between-burrow effects of the age of the breeding wall revealed that a decline in re-occupation probability with individual burrow age was responsible for this and not a selective disappearance of burrows with high re-occupation probability over time. Limited duty cycles of individual burrows may be caused by accumulating detritus or decreasing stability with increasing burrow age. Alternatively, burrow fidelity may presuppose pair fidelity which may also explain the observed restricted burrow reuse duty cycles. A consequent next step would be to extend our within-colony approach to other colonies and compare the ecological circumstances under which bee-eaters reuse breeding burrows. PMID:26355473

  3. Rodents new to the diet of the western burrowing owl(athene CUNICULARIA HYPUGAEA )

    USGS Publications Warehouse

    Wiluford, D.L.; Woodin, M.C.; Skoruppa, M.K.; Hickman, G.C.

    2009-01-01

    The northern pygmy mouse (Baiomys taylori), fulvous harvest mouse (Reithrodontomys fulvescens), and Merriam's pocket mouse (Pemgnathus merriami) are new to the diet of the western burrowing owl (Athene cuniculana hypugaed). All three species were identified from remains in regurgitated pellets collected from roost sites of burrowing owls in southern Texas over a period of 4 winters. Together, northern pygmy mice and fulvous harvest mice represented 58% of mammals identified in 182 pellets regurgitated by western burrowing owls. Merriam's pocket mouse accounted for only 4% of identified mammalian prey. Frequency of occurrence in pellets was 16% for northern pygmv mice, 11% for fulvous harvest mice, and 3% for Merriam's pocket mice. The primary reason for absence of these species in previous studies of foods of western burrowing owls is that most were conducted in latitudes north of these southern-distributed species of mammals.

  4. MORE THAN JUST BAIT: BURROWING SHRIMP AS ECOSYSTEM ENGINEERS IN OREGON ESTUARIES - SEPTEMBER 2006

    EPA Science Inventory

    Burrowing shrimp may be most widely known as excellent fishing bait, but they also play important roles in estuaries of the Pacific Northwest. These shrimps strongly affect carbon and nutrient cycling, phytoplankton abundance, food web structure and dynamics, sediment stability,...

  5. Effects of Hypoxia on Animal Burrow Constraction and Consequent Effects on Sediment Redox Profiles (SETAC08)

    EPA Science Inventory

    We investigated the effects of mild hypoxia on the burrowing behavior of three marine species (the hard clam Mercenaria mercenaria, the polychaete worm Nereis virens, and the amphipod Leptocheirus plumulosus) and consequent effects on sediment redox profiles. Animals were introdu...

  6. Crab burrows as conduits for groundwater-surface water exchange in Bangladesh

    NASA Astrophysics Data System (ADS)

    Stahl, Mason O.; Tarek, M. H.; Yeo, Darren C. J.; Badruzzaman, A. B. M.; Harvey, Charles F.

    2014-12-01

    Groundwater recharge affects water budgets and groundwater quality on the deltas and floodplains of South and Southeast Asia. Rain and flooding rivers recharge groundwater during the monsoon; irrigated rice fields and surface water bodies recharge aquifers during the dry season. Groundwater throughout the region is severely contaminated by arsenic, and recent research suggests that quantifying and characterizing recharge is important to understand whether recharge flushes or mobilizes arsenic from aquifers. At a field site in Bangladesh, we found that burrows of terrestrial crabs short-circuit low-permeability surface sediments, providing the primary conduit for recharge. We combine field observations along with a model that couples isotope and water balances to quantify the effect of crab burrows on aquifer recharge. Given the wide distribution of burrowing crabs and the surficial geology, we suggest that crab burrows provide widespread conduits for groundwater recharge.

  7. Estimating Occupancy of Gopher Tortoise (Gorpherus polyphemus) Burrows in Coastal Scrub and Slash Pine Flatwoods

    NASA Technical Reports Server (NTRS)

    Breininger, David R.; Schmalzer, Paul A.; Hinkle, C. Ross

    1991-01-01

    One hundred twelve plots were established in coastal scrub and slash pine flatwoods habitats on the John F. Kennedy Space Center (KSC) to evaluate relationships between the number of burrows and gopher tortoise (Gopherus polyphemus) density. All burrows were located within these plots and were classified according to tortoise activity. Depending on season, bucket trapping, a stick method, a gopher tortoise pulling device, and a camera system were used to estimate tortoise occupancy. Correction factors (% of burrows occupied) were calculated by season and habitat type. Our data suggest that less than 20% of the active and inactive burrows combined were occupied during seasons when gopher tortoises were active. Correction factors were higher in poorly-drained areas and lower in well-drained areas during the winter, when gopher tortoise activity was low. Correction factors differed from studies elsewhere, indicating that population estimates require correction factors specific to the site and season to accurately estimate population size.

  8. Documenting Western Burrowing Owl Reproduction and Activity Patterns Using Motion-Activated Cameras

    SciTech Connect

    Hall, Derek B.; Greger, Paul D.

    2014-08-01

    We used motion-activated cameras to monitor the reproduction and patterns of activity of the Burrowing Owl (Athene cunicularia) above ground at 45 burrows in south-central Nevada during the breeding seasons of 1999, 2000, 2001, and 2005. The 37 broods, encompassing 180 young, raised over the four years represented an average of 4.9 young per successful breeding pair. Young and adult owls were detected at the burrow entrance at all times of the day and night, but adults were detected more frequently during afternoon/early evening than were young. Motion-activated cameras require less effort to implement than other techniques. Limitations include photographing only a small percentage of owl activity at the burrow; not detecting the actual number of eggs, young, or number fledged; and not being able to track individual owls over time. Further work is also necessary to compare the accuracy of productivity estimates generated from motion-activated cameras with other techniques.

  9. Burrowing mayflies (Hexagenia) as indicators of ecosystem health at Sleeping Bear Dunes National Lakeshore, Michigan

    USGS Publications Warehouse

    Edsall, Thomas A.; Phillips, William E.

    2004-01-01

    The present study describes the provisional use of burrowing mayflies (Hexagenia [Ephemeroptera: Ephemeridae]) as an indicator organism to assess and monitor the health of the Loon Lake and lower Platte River ecosystem within Sleeping Bear Dunes National Lakeshore, Michigan.

  10. Mechanics and Energetics of Excavation by Burrowing Wolf Spiders, Geolycosa spp.

    PubMed Central

    Suter, Robert B.; Stratton, Gail E.; Miller, Patricia R.

    2011-01-01

    Burrowing wolf spiders, Geolycosa sp. (Araneae:Lycosidae), excavate vertical burrows and inhabit them throughout their lives or, in the case of males, until they mature and wander in search of mates. Three species: G. fatifera Kurata, G. missouriensis Banks, and G. rogersi Wallace were studied to understand how and at what expense the burrowing is accomplished. Normal and high-speed videography coupled with scanning electron microscopy revealed (a) that the convex surfaces of the two fangs, together, constitute the digging tool, (b) that boluses of soil are transported to the burrow entrance on the anterior surfaces of the chelicerae held there by the pedipalps, and (c) that each bolus is either incorporated into the growing turret or flung away, propelled by the forelegs. To elucidate the energetics of burrow construction, burrow volumes were calculated and then the costs associated with dislodging, elevating, and throwing the known volumes of soil were measured. A typical Geolycosa burrow, at a volume of 23.6 ± 2.0 ml and a depth of 13.2 ± 0.7 cm, required the removal of 918 boluses each weighing about 34 mg. The aggregate dislodging cost was close to 1.9 Joules in sand/sandy loam and 5.6 J in clayey subsoil, the work against gravity necessary to raise all of the boluses to the surface was about 0.13 J, and the aggregate cost of flinging the boluses was close to 0.014 J. Assuming that the ratio of external work to metabolic cost of external work is between 0.20 and 0.25 in spiders, the real cost of burrow construction would be between 8 J and 29 J, depending primarily on soil type. This is a small but not negligible cost when placed in the context of reproductive effort: a single Geolycosa egg, dozens to hundreds of which are produced in a clutch, contains about 10 J. PMID:21529154

  11. Winter Ecology of the Western Burrowing Owl (Athene cunicularia hypugaea) in Southern Texas 1999-2004

    USGS Publications Warehouse

    Woodin, Marc C.; Skoruppa, Mary K.; Hickman, Graham C.

    2007-01-01

    This study examines the winter ecology of the western burrowing owl (Athene cunicularia hypugaea) in five Texas counties surrounding Corpus Christi, in southern Texas. There is a substantial gap in information on the owl's life cycle during migration and non-breeding winter months; almost all previous research on western burrowing owls has been conducted during the breeding season. The western burrowing owl currently is federally threatened in Mexico, federally endangered in Canada, and in the United States is considered a National Bird of Conservation Concern by the U.S. Fish and Wildlife Service. Topics investigated included status, effectiveness of public outreach, roost sites and use of culverts and artificial burrows, roost site fidelity, diet, contaminant burdens, body mass, and ectoparasites. Early ornithological reports and a museum egg set revealed that burrowing owls once bred in southern Texas and were common in winter; however, since the 1950's they have been reported in relatively low numbers and only during winter. In this study, public outreach increased western burrowing owl detections by 68 percent. Owls selected winter roost sites with small-diameter openings, including culverts less than or equal to 16 centimeters and artificial burrows of 15 centimeters, probably because the small diameters deterred mammalian predators. Owls showed strong roost site fidelity; 15 banded birds stayed at the same roost sites within a winter, and 8 returned to the same site the following winter. The winter diet was over 90 percent insects, with crickets the primary prey. Analyses of invertebrate prey and regurgitated pellets showed that residues of all but 3 of 28 carbamate and organophosphate pesticides were detected at least once, but all were below known lethal concentrations. Mean body mass of western burrowing owls was 168 grams and was highest in midwinter. Feather lice were detected in low numbers on a few owls, but no fleas or other ectoparasites were found.

  12. Balancing the competing requirements of saltatorial and fossorial specialisation: burrowing costs in the spinifex hopping mouse, Notomys alexis.

    PubMed

    White, Craig R; Matthews, Philip G D; Seymour, Roger S

    2006-06-01

    Semi-fossorial animals (burrowing surface foragers) need to balance the competing morphological requirements of terrestrial and burrowing locomotion. These species rarely show the same degree of claw, forelimb and pectoral girdle structural development that fully fossorial forms (burrowing subterranean foragers) do, but nevertheless invest considerable amounts of energy in burrow systems. The compromise between terrestrial and burrowing locomotion was investigated by measuring net costs of burrowing and pedestrian transport in the spinifex hopping mouse, Notomys alexis, a species that forages in open areas in arid environments and is adapted for saltatorial locomotion. The net cost of transport by burrowing of hopping mice was found to be more expensive than for specialised fossorial species, and burrows were estimated to represent an energy investment equivalent to the terrestrial locomotion expected to be incurred in 17-100 days. A phylogenetically independent-contrasts approach revealed that morphological specialisation for burrowing was associated with low maximum running speeds in fossorial mammals and, for non-fossorial rodents and marsupials, maximum running speed was positively correlated with an index of habitat structure that ranged from arboreal to open desert. The high terrestrial speeds attainable by this semi-fossorial species by saltatory locomotion apparently outweigh the energetic savings that would be associated with burrowing specialisation. PMID:16709912

  13. Burrowing by small polychaetes - mechanics, behavior and muscle structure of Capitella sp.

    PubMed

    Grill, Susann; Dorgan, Kelly M

    2015-05-15

    Worms of different sizes extend burrows through muddy sediments by fracture, applying dorso-ventral forces that are amplified at the crack tip. Smaller worms displace sediments less than larger worms and therefore are limited in how much force they can apply to burrow walls. We hypothesized that small worms would exhibit a transition in burrowing mechanics, specifically a lower limit in body size for the ability to burrow by fracture, corresponding with an ontogenetic transition in muscle morphology. Kinematics of burrowing in a mud analog, external morphology and muscle arrangement were examined in juveniles and adults of the small polychaete Capitella sp. We found that it moves by peristalsis, and no obvious differences were observed among worms of different sizes; even very small juveniles were able to burrow through a clear mud analog by fracture. Interestingly, we found that in addition to longitudinal and circular muscles needed for peristaltic movements, left- and right-handed helical muscles wrap around the thorax of worms of all sizes. We suggest that in small worms helical muscles may function to supplement forces generated by longitudinal muscles and to maintain hydrostatic pressure, enabling higher forces to be exerted on the crack wall. Further research is needed, however, to determine whether surficial sediments inhabited by small worms fail by fracture or plastically deform under forces of the magnitudes applied by Capitella sp. PMID:25827841

  14. Ventilatory and intrapulmonary chemoreceptor sensitivity to CO2 in the burrowing owl.

    PubMed

    Kilgore, D L; Faraci, F M; Fedde, M R

    1985-12-01

    We measured the ventilatory response of anesthetized, unidirectionally ventilated pigeons and burrowing owls to changes in intrapulmonary CO2 concentration and the static CO2 sensitivity of intrapulmonary chemoreceptors (IPC) in these species and the domestic goose. Compared with pigeons, burrowing owls showed a significantly reduced respiratory frequency and amplitude response to increases in FICO2 from 0.05 to 0.10, which corroborates similar findings in intact, awake individuals of the same species. The average static CO2 sensitivity of IPC in geese, pigeons, and burrowing owls, as reflected by the average slope of the linear regressions of receptor discharge frequency on ln(PICO2), was -7.96, -11.1 and -6.87 imp/sec . ln(PICO2), respectively. The sensitivities of individual receptors were normally distributed in geese and pigeons, but skewed in burrowing owls. Therefore, the median CO2 sensitivity [-5.50 imp/sec . ln(PICO2)] is a more appropriate measure of the typical CO2 sensitivity of IPC in burrowing owls. The static CO2 sensitivity of IPC in burrowing owls is the lowest reported for euthermic birds with a normal acid-base balance and may materially contribute to the blunted ventilatory response of these birds to the elevated CO2 levels they encounter in nature. PMID:3937191

  15. Recruitment by Brainstorming.

    ERIC Educational Resources Information Center

    Hankin, Joseph N.

    1982-01-01

    Reports on Westchester Community College's (WCC's) campuswide brainstorming meetings which prepared strategies, programs, and recommendations for realizing recruitment goals. Includes a draft of WCC's 1981 Marketing Recruitment Plan, which covers programs and instruction, services, admissions office and processes, publications, and…

  16. Recruitment and Training. Symposium.

    ERIC Educational Resources Information Center

    2002

    This document contains three papers from a symposium on recruitment and training. "College Choice: The State of Marketing and Effective Student Recruitment Strategies" (Fredrick Muyia Nafukho, Michael F. Burnett) reports on a study of the recruitment strategies used by Louisiana State University's admissions office and College of Agriculture that…

  17. Population models of burrowing mayfly recolonization in Western Lake Erie

    USGS Publications Warehouse

    Madenjian, C.P.; Schloesser, D.W.; Krieger, K.A.

    1998-01-01

    Burrowing mayflies, Hexagenia spp. (H. limbata and H. rigida), began recolonizing western Lake Erie during the 1990s. Survey data for mayfly nymph densities indicated that the population experienced exponential growth between 1991 and 1997. To predict the time to full recovery of the mayfly population, we fitted logistic models, ranging in carrying capacity from 600 to 2000 nymphs/m2, to these survey data. Based on the fitted logistic curves, we forecast that the mayfly population in western Lake Erie would achieve full recovery between years 1998 and 2000, depending on the carrying capacity of the western basin. Additionally, we estimated the mortality rate of nymphs in western Lake Erie during 1994 and then applied an age-based matrix model to the mayfly population. The results of the matrix population modeling corroborated the exponential growth model application in that both methods yielded an estimate of the population growth rate, r, in excess of 0.8 yr-1. This was the first evidence that mayfly populations are capable of recolonizing large aquatic ecosystems at rates comparable with those observed in much smaller lentic ecosystems. Our model predictions should prove valuable to managers of power plant facilities along the western basin in planning for mayfly emergences and to managers of the yellow perch (Perca flavescens) fishery in western Lake Erie.

  18. High-resolution computed tomography reconstructions of invertebrate burrow systems

    PubMed Central

    Hale, Rachel; Boardman, Richard; Mavrogordato, Mark N.; Sinclair, Ian; Tolhurst, Trevor J.; Solan, Martin

    2015-01-01

    The architecture of biogenic structures can be highly influential in determining species contributions to major soil and sediment processes, but detailed 3-D characterisations are rare and descriptors of form and complexity are lacking. Here we provide replicate high-resolution micro-focus computed tomography (μ-CT) data for the complete burrow systems of three co-occurring, but functionally contrasting, sediment-dwelling inter-tidal invertebrates assembled alone, and in combination, in representative model aquaria. These data (≤2,000 raw image slices aquarium−1, isotropic voxel resolution, 81 μm) provide reference models that can be used for the development of novel structural analysis routines that will be of value within the fields of ecology, pedology, geomorphology, palaeobiology, ichnology and mechanical engineering. We also envisage opportunity for those investigating transport networks, vascular systems, plant rooting systems, neuron connectivity patterns, or those developing image analysis or statistics related to pattern or shape recognition. The dataset will allow investigators to develop or test novel methodology and ideas without the need to generate a complete three-dimensional computation of exemplar architecture. PMID:26396743

  19. High-resolution computed tomography reconstructions of invertebrate burrow systems.

    PubMed

    Hale, Rachel; Boardman, Richard; Mavrogordato, Mark N; Sinclair, Ian; Tolhurst, Trevor J; Solan, Martin

    2015-01-01

    The architecture of biogenic structures can be highly influential in determining species contributions to major soil and sediment processes, but detailed 3-D characterisations are rare and descriptors of form and complexity are lacking. Here we provide replicate high-resolution micro-focus computed tomography (μ-CT) data for the complete burrow systems of three co-occurring, but functionally contrasting, sediment-dwelling inter-tidal invertebrates assembled alone, and in combination, in representative model aquaria. These data (≤ 2,000 raw image slices aquarium(-1), isotropic voxel resolution, 81 μm) provide reference models that can be used for the development of novel structural analysis routines that will be of value within the fields of ecology, pedology, geomorphology, palaeobiology, ichnology and mechanical engineering. We also envisage opportunity for those investigating transport networks, vascular systems, plant rooting systems, neuron connectivity patterns, or those developing image analysis or statistics related to pattern or shape recognition. The dataset will allow investigators to develop or test novel methodology and ideas without the need to generate a complete three-dimensional computation of exemplar architecture. PMID:26396743

  20. Burrowing mayfly populations in Chequamegon Bay, Wisconsin: 2002 and 2012

    USGS Publications Warehouse

    Brunk, Kristin M.; Vinson, Mark R.; Ogle, Derek H.; Evrard, Lori M.

    2014-01-01

    Burrowing mayflies (Ephemeroptera: Ephemeridae) are sensitive to pollution and have been used as environmental indicators in the Great Lakes. Hexagenia limbata and Ephemera simulans population abundance and biomass estimates from Chequamegon Bay, Lake Superior, were compared between the years 2002 and 2012 as well as inside and outside the Northern States Power Lakefront Superfund site. Mean abundance was similar and mean biomass of Ephemeridae was slightly less in 2012 than in 2002, most likely due to the occurrence of E. simulans in 2012, a smaller species not collected in 2002. In 2012, mean ephemerid abundance and biomass outside the Superfund site was significantly higher than inside the Superfund site. Biomass was higher in clay, clay with sand, and sand with clay substrates than in fine sand, coarse sand, or wood debris substrates. Substrate in the Superfund site was predominantly wood debris. Future monitoring of ephemerid populations in Chequamegon Bay, and particularly in the Superfund site as clean up begins, would be valuable to establish long-term population trends for these two species and potentially shed light on the habitat requirements of E. simulans, an understudied species in the Great Lakes.

  1. Multi-threading the generation of Burrows-Wheeler Alignment.

    PubMed

    Jo, H

    2016-01-01

    Along with recent progress in next-generation sequencing technology, it has become easier to process larger amounts of genome sequencing data at a lower cost. The most time-consuming step of next-generation sequencing data analysis involves the mapping of read data into a reference genome. Although the Burrows-Wheeler Alignment (BWA) tool is one of the most widely used open-source software tools for aligning read sequences, it still has a limitation in that it does not fully support a multi-thread mechanism during the alignment generation step. In this article, we propose a BWA-MT tool based on BWA that supports multi-thread mechanisms for processing alignment generation. To evaluate BWA-MT, we used an evaluation system equipped with 24 cores and 128 GB of memory. As workloads, we used the hg19 human genome reference sequence and sequences of various read sizes from the 1 to 40 M spots. In our evaluation, BWA-MT showed a maximum of 3.66-times better performance, and generated the same Sequence Alignment/Map result file as that of BWA. Although the ability to speed up the procedure might be dependent on computing resources, we confirmed that BWA-MT is a highly effective and fast alignment tool. PMID:27323088

  2. Use of mammal manure by nesting burrowing owls: a test of four functional hypotheses

    USGS Publications Warehouse

    Smith, M.D.; Conway, C.J.

    2007-01-01

    Animals have evolved an impressive array of behavioural traits to avoid depredation. Olfactory camouflage of conspicuous odours is a strategy to avoid depredation that has been implicated only in a few species of birds. Burrowing owls, Athene cunicularia, routinely collect dried manure from mammals and scatter it in their nest chamber, in the tunnel leading to their nest and at the entrance to their nesting burrow. This unusual behaviour was thought to reduce nest depredation by concealing the scent of adults and juveniles, but a recent study suggests that manure functions to attract arthropod prey. However, burrowing owls routinely scatter other materials in the same way that they scatter manure, and this fact seems to be at odds with both of these hypotheses. Thus, we examined the function of this behaviour by testing four alternative hypotheses. We found no support for the widely cited olfactory-camouflage hypothesis (manure did not lower the probability of depredation), or for the mate-attraction hypothesis (males collected manure after, not before, pair formation). Predictions of the burrow-occupied hypothesis (manure indicates occupancy to conspecifics and thereby reduces agonistic interactions) were supported, but results were not statistically significant. Our results also supported several predictions of the prey-attraction hypothesis. Pitfall traps at sampling sites with manure collected more arthropod biomass (of taxa common in the diet of burrowing owls) than pitfall traps at sampling sites without manure. Scattering behaviour of burrowing owls appears to function to attract arthropod prey, but may also signal occupancy of a burrow to conspecifics. ?? 2006 The Association for the Study of Animal Behaviour.

  3. Orange carotenoid protein burrows into the phycobilisome to provide photoprotection.

    PubMed

    Harris, Dvir; Tal, Ofir; Jallet, Denis; Wilson, Adjélé; Kirilovsky, Diana; Adir, Noam

    2016-03-22

    In cyanobacteria, photoprotection from overexcitation of photochemical centers can be obtained by excitation energy dissipation at the level of the phycobilisome (PBS), the cyanobacterial antenna, induced by the orange carotenoid protein (OCP). A single photoactivated OCP bound to the core of the PBS affords almost total energy dissipation. The precise mechanism of OCP energy dissipation is yet to be fully determined, and one question is how the carotenoid can approach any core phycocyanobilin chromophore at a distance that can promote efficient energy quenching. We have performed intersubunit cross-linking using glutaraldehyde of the OCP and PBS followed by liquid chromatography coupled to tandem mass spectrometry (LC/MS-MS) to identify cross-linked residues. The only residues of the OCP that cross-link with the PBS are situated in the linker region, between the N- and C-terminal domains and a single C-terminal residue. These links have enabled us to construct a model of the site of OCP binding that differs from previous models. We suggest that the N-terminal domain of the OCP burrows tightly into the PBS while leaving the OCP C-terminal domain on the exterior of the complex. Further analysis shows that the position of the small core linker protein ApcC is shifted within the cylinder cavity, serving to stabilize the interaction between the OCP and the PBS. This is confirmed by a ΔApcC mutant. Penetration of the N-terminal domain can bring the OCP carotenoid to within 5-10 Å of core chromophores; however, alteration of the core structure may be the actual source of energy dissipation. PMID:26957606

  4. The influence of foraging mode and arid adaptation on the basal metabolic rates of burrowing mammals.

    PubMed

    White, Craig R

    2003-01-01

    Two competing but nonexclusive hypotheses to explain the reduced basal metabolic rate (BMR) of mammals that live and forage underground (fossorial species) are examined by comparing this group with burrowing mammals that forage on the surface (semifossorial species). These hypotheses suggest that the low BMR of fossorial species either compensates for the enormous energetic demands of subterranean foraging (the cost-of-burrowing hypothesis) or prevents overheating in closed burrow systems (the thermal-stress hypothesis). Because phylogentically informed allometric analysis showed that arid burrowing mammals have a significantly lower BMR than mesic ones, fossorial and semifossorial species were compared within these groups. The BMRs of mesic fossorial and semifossorial mammals could not be reliably distinguished, nor could the BMRs of large (>77 g) arid fossorial and semifossorial mammals. This finding favours the thermal-stress hypothesis, because the groups appear to have similar BMRs despite differences in foraging costs. However, in support of the cost-of-burrowing hypothesis, small (<77 g) arid fossorial mammals were found to have a significantly lower BMR than semifossorial mammals of the similar size. Given the high mass-specific metabolic rates of small animals, they are expected to be under severe energy and water stress in arid environments. Under such conditions, the greatly reduced BMR of small fossorial species may compensate for the enormous energetic demands of subterranean foraging. PMID:12695993

  5. Footprints in the sand: independent reduction of subdigital lamellae in the Namib–Kalahari burrowing geckos

    PubMed Central

    Lamb, Trip; Bauer, Aaron M

    2005-01-01

    Many desert organisms exhibit convergence, and certain physical factors such as windblown sands have generated remarkably similar ecomorphs across divergent lineages. The burrowing geckos Colopus, Chondrodactylus and Palmatogecko occupy dune ecosystems in the Namib and Kalahari deserts of southwest Africa. Considered closely related, they share several putative synapomorphies, including reduced subdigital pads (toe pads) and spinose digital scales. Though recognized as part of Africa's ecologically diverse Pachydactylus Group, the burrowing geckos' precise phylogenetic affinities remain elusive. Convergent pedal modification provides a tenable alternative explaining the geckos' derived terrestriality and adaptation to Namib and Kalahari sands. We generated a molecular phylogeny for the Pachydactylus Group to examine evolutionary relationships among the burrowing geckos and infer historical patterns of pedal character change. Bayesian and parsimony analyses revealed all three burrowing genera to be deeply nested within Pachydactylus, each genus belonging to a separate clade. Strong support for these distinct clades indicates ecomorphological adaptations for burrowing have evolved independently three times in the southern Pachydactylus Group. We argue that the physical properties of Namib and Kalahari sands played a principal role in selecting for pedal similarity. PMID:16618680

  6. Burrow plugging in the crab Uca uruguayensis and its synchronization with photoperiod and tides.

    PubMed

    de la Iglesia, H O; Rodríguez, E M; Dezi, R E

    1994-05-01

    Field observations and laboratory experiments were performed to analyze the burrow plugging behavior of U. uruguayensis and to analyze its relation to two environmental cycles: light-dark cycle and tides. Field observations showed that burrow plugging is a rhythmic behavior synchronized with both environmental cycles such that burrows are open during those periods of simultaneous light and low tide. Laboratory experiments suggested that the plugging rhythm is under endogenous circadian control, whereas its synchronization with the tidal cycle, particularly with periodic inundation, seems to be strongly exogenous, not showing clear circatidal components. It is proposed that burrow plugging is adaptive because it allows the animals to be within an air medium, more suitable for their respiration modality, during high tide and because it prevents burrow collapse. It is also proposed that both the endogenous circadian component and the lack of an endogenous circatidal component can also be explained on the basis of adaptive value, taking into account the regular temporal structure of the solar day and the irregular temporal structure of the tidal cycle. PMID:8022913

  7. Evidence for and geomorphologic consequences of a reptilian ecosystem engineer: The burrowing cascade initiated by the Gopher Tortoise

    NASA Astrophysics Data System (ADS)

    Kinlaw, A.; Grasmueck, M.

    2012-07-01

    Physical ecosystem engineers often make major, durable physical constructs that can provide living space for other species and can structure local animal communities over evolutionary time. In Florida, a medium sized chelonian, the Gopher Tortoise (Gopherus polyphemus) will excavate extensive subterranean chambers that can endure for long periods of time. The tortoise starts a 'burrowing cascade', by first excavating a larger burrow that may extend 10 m, which is then re-engineered by Florida Mice (Podomys floridanus) and other rodents that dig smaller side-burrows and pockets. This sequence is often followed by an invertebrate, the camel cricket (Ceuthophilus labibuli) which is reported to excavate even smaller chambers. Our first aim was to quantify the zoogeomorphic impact of this burrowing cascade by measuring the amount of soil excavated in a large sample of burrows in two communities. Secondly, we hypothesized that the high biodiversity reported for these structures might be related to the quasi-fractal nature of the geometry, following the work of Frontier (1987). To visualize this underground geometry, we used high-resolution 3D Ground Penetrating Radar (GPR), which provided images and insights previously unobtainable using excavations or 2D GPR. Our images verified that the active tortoise burrow had a spiraling shape, but also showed splits in the larger burrow apparently dug by tortoises. For the first time, the smaller Florida Mouse burrows were imaged, showing side loops that exit and re-renter the tortoise burrow. This study also presents new information by making the discovery of numerous remnants of past tortoise burrows underground in the sampling grid surrounding the active burrow. Our third aim was to interpret our field results with previous ecological field studies to evaluate the strength of evidence that this species ranks as an ecosystem engineer.

  8. Breeding-season food habits of burrowing owls (Athene cunicularia) in southwestern Dominican Republic

    USGS Publications Warehouse

    Wiley, J.W.

    1998-01-01

    Diet data from 20 Burrowing Owl (Athene cunicularia) nests were collected in southwestern Dominican Republic in 1976, 1982, and 1996. Invertebrates (53.3%) comprised the most numerous prey items (N = 396) delivered to nests by adult owls, but vertebrates (46.7%) were much better represented than in other studies of Burrowing Owl diet. Among vertebrates, birds (28.3% of all items) and reptiles (14.9%) were most important, whereas mammals (1.0%) and amphibians (2.5%) were less commonly delivered to nests. Vertebrates, however, comprised more than twice (69.2%) of the total biomass as invertebrates (30.8%), with birds (50.4%) and reptiles (12.8%) the most important of the vertebrate prey classes. A positive relationship was observed between bird species abundance and number of individuals taken as prey by Burrowing Owls.

  9. The soil-dwelling earthworm Allolobophora chlorotica modifies its burrowing behaviour in response to carbendazim applications.

    PubMed

    Ellis, Sian R; Hodson, Mark E; Wege, Philip

    2010-09-01

    Carbendazim-amended soil was placed above or below unamended soil. Control tests comprised two layers of unamended soil. Allolobophora chlorotica earthworms were added to either the upper or the unamended soil. After 72 h vertical distributions of earthworms were compared between control and carbendazim-amended experiments. Earthworm distributions in the carbendazim-amended test containers differed significantly from the 'normal' distribution observed in the control tests. In the majority of the experiments, earthworms significantly altered their burrowing behaviour to avoid carbendazim. However, when earthworms were added to an upper layer of carbendazim-amended soil they remained in this layer. This non-avoidance is attributed to (1) the earthworms' inability to sense the lower layer of unamended soil and (2) the toxic effect of carbendazim inhibiting burrowing. Earthworms modified their burrowing behaviour in response to carbendazim in the soil. This may explain anomalous results observed in pesticide field trials when carbendazim is used as a control substance. PMID:20580088

  10. Habitat requirements and burrowing depths of rodents in relation to shallow waste burial sites

    SciTech Connect

    Gano, K.A.; States, J.B.

    1982-05-01

    The purpose of this paper is to provide a review of the literature and summarize information on factors affecting habitat selection and maximum recorded burrowing depths for representative small mammals that we consider most likely to inhibit waste burial sites in arid and semi-arid regions of the West. The information is intended for waste management designers who need to know what to expect from small mammals that may be present at a particular site. Waste repositories oculd be designed to exclude the deep burrowing rodents of a region by creating an unattractive habitat over the waste. Summaries are given for habitat requirements of each group along with generalized modifications that could be employed to deter habitation. Representatives from the major groups considered to be deep burrowers are discussed. Further, detailed information about a particular species can be obtained from the references cited.

  11. An Analysis of Spatial Clustering and Implications for Wildlife Management: A Burrowing Owl Example

    NASA Astrophysics Data System (ADS)

    Fisher, Joshua B.; Trulio, Lynne A.; Biging, Gregory S.; Chromczak, Debra

    2007-03-01

    Analysis tools that combine large spatial and temporal scales are necessary for efficient management of wildlife species, such as the burrowing owl ( Athene cunicularia). We assessed the ability of Ripley’s K-function analysis integrated into a geographic information system (GIS) to determine changes in burrowing owl nest clustering over two years at NASA Ames Research Center. Specifically, we used these tools to detect changes in spatial and temporal nest clustering before, during, and after conducting management by mowing to maintain low vegetation height at nest burrows. We found that the scale and timing of owl nest clustering matched the scale and timing of our conservation management actions over a short time frame. While this study could not determine a causal link between mowing and nest clustering, we did find that Ripley’s K and GIS were effective in detecting owl nest clustering and show promise for future conservation uses.

  12. An analysis of spatial clustering and implications for wildlife management: a burrowing owl example.

    PubMed

    Fisher, Joshua B; Trulio, Lynne A; Biging, Gregory S; Chromczak, Debra

    2007-03-01

    Analysis tools that combine large spatial and temporal scales are necessary for efficient management of wildlife species, such as the burrowing owl (Athene cunicularia). We assessed the ability of Ripley's K-function analysis integrated into a geographic information system (GIS) to determine changes in burrowing owl nest clustering over two years at NASA Ames Research Center. Specifically, we used these tools to detect changes in spatial and temporal nest clustering before, during, and after conducting management by mowing to maintain low vegetation height at nest burrows. We found that the scale and timing of owl nest clustering matched the scale and timing of our conservation management actions over a short time frame. While this study could not determine a causal link between mowing and nest clustering, we did find that Ripley's K and GIS were effective in detecting owl nest clustering and show promise for future conservation uses. PMID:17253092

  13. Belted kingfishers: Under surveillance and sampled in the privacy of their own burrow

    SciTech Connect

    Baron, L.A.; Ashwood, T.L.

    1995-12-31

    The belted kingfisher, a common piscivore of the Oak Ridge Reservation (ORR), bioaccumulates contaminants from consumption of aquatic prey. Three kingfisher carcasses found near contaminated streams on the ORR were analyzed. Mercury, cadmium, and selenium bioaccumulated within the liver, kidney, and feathers. Additionally, PCB-1254 accumulated in muscle and lipid tissue, while Cesium-137 accumulated within the muscle and whole body. These contaminant levels have been shown to produce a variety of toxicological effects (i.e., reproductive impairment, central nervous system dysfunction) within other species of birds. In addition to use of this data for ecological risk assessment, kingfishers can also be monitored as a viable bioindicator species reflecting environmental contaminant levels over time. However, current sampling methods of burrow excavation or the use of mist nets can be detrimental to the reproductive success of the birds. The authors present a method for obtaining adequate samples of feathers and other remnants (i.e., egg shells, dried regurgitant) found in the burrow during or following the nesting season. The collection of samples following surveillance of the burrow and its contents was performed with the use of a 15 ft-long flexible, portable probe containing a video camera. Once sighted with the probe, contents of the burrow were collected by insertion of an additional tube attached to a hand held vacuum cleaner (Dirt Devil{reg_sign}). Feathers collected from a nest at an uncontaminated site contained selenium, lead and mercury. Cesium-137 was found in an egg shell collected from a nest at a radiologically contaminated site. Close-up photos of a kingfisher mother incubating her eggs and nestlings within two burrows will also be shown. This surveillance and sampling technique can also be used for monitoring other burrowing terrestrial species.

  14. Recruiting Minority Students.

    ERIC Educational Resources Information Center

    Reed, Bobette P.; Dandridge, William L.

    To help improve private schools' recruitment of minority students, this handbook discusses where and how to begin, recruitment strategies, applicant assessment, and the need for in-school support systems for minority students. The authors stress that each school should begin by analyzing its own objectives, attitudes, and admission program.…

  15. Recruiting New Teachers.

    ERIC Educational Resources Information Center

    Camp, William G.; And Others

    1997-01-01

    This special theme issue includes: "How Can We Solve the Teacher Shortage?" (Camp); "A Student's Perspective" (Swafford); "Recruitment" (Dyer, Andreasen); "Top 10 Reasons to Become an Agriculture Teacher and FFA Advisor" (Bembardt, McMaben); "Supply and Demand of Agriculture Teachers since 1965" (Brown); "Recruitment and Retention of Agricultural…

  16. Identification and Recruitment Guide.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Div. of Compensatory Education.

    The guide contains basic information to assist local recruiters for the North Carolina migrant education project in the identification and recruitment of children eligible for the project. Eleven terms pertaining to eligibility requirements are defined, and eligibility is explained. The guide suggests and explains information sources available to…

  17. DENSITY-DEPENDENT IMPACTS OF BIOIRRIGATION BY THE BURROWING SHRIMP UPOGEBIA PUGETTENSIS ON BENTHIC FLUXES AND POREWATER SOLUTE DISTRIBUTIONS IN PACIFIC NORTHWEST ESTUARIES

    EPA Science Inventory

    Burrowing thalassinid shrimp are major ecosystem engineering species of Pacific estuaries and can structure the physical, chemical, and biotic properties of sediments. Feeding and burrow irrigation by benthic organisms can increase the remineralization rates of organic material (...

  18. Behavioural and Physiological Implications of a Burrow-dwelling Lifestyle for Two Species of Upogebiid Mud-shrimp (Crustacea: Thalassinidea)

    NASA Astrophysics Data System (ADS)

    Astall, C. M.; Taylor, A. C.; Atkinson, R. J. A.

    1997-02-01

    Upogebia stellataand U. deltaura(Crustacea: Thalassinidea) construct burrows in nearshore sediments in U.K. waters. Burrow structure is similar in both species; the basic burrow consisting of a two-opening, U-shaped section with a vertical shaft descending from the mid-point of the U. This structure may be variously elaborated. Burrow cross-section is circular, dilations allow turning by somersaulting and surface openings are often constricted. Conditions within the burrows are usually hypoxic and hypercapnic. Burrow water PO 2in the parts normally occupied by the mud-shrimp was between 80-110 Torr, but was much lower (10-45 Torr) in the deepest, poorly-irrigated parts. Both species irrigate their burrows by episodes of pleopod beating of variable duration (mean=8·5±3·5 min and 2·8±0·5 min for U. deltauraand U. stellata, respectively), which draws oxygenated water into the burrow and also particulate food for suspension feeding. When exposed to hypoxia, U. deltauraand U. stellatawere able to maintain their rates of oxygen consumption approximately constant over a wide range of PO 2( Pc=30-50 Torr). Under these conditions, there was a pronounced increase in scaphognathite beat rate but heart rate remained relatively constant. Below the Pc, however, both rates declined.

  19. Ontogenetic habitat shift, population growth, and burrowing behavior of the Indo-Pacific beach star, Archaster typicus (Echinodermata; Asteroidea).

    PubMed

    Bos, Arthur R; Gumanao, Girley S; van Katwijk, Marieke M; Mueller, Benjamin; Saceda, Marjho M; Tejada, Rosie Lynn P

    2011-01-01

    Archaster typicus, a common sea star in Indo-Pacific regions, has been a target for the ornamental trade, even though little is known about its population biology. Spatial and temporal patterns of abundance and size structure of A. typicus were studied in the Davao Gulf, the Philippines (125°42.7'E, 7°0.6'N), from February 2008 to December 2009. Specimens of A. typicus were associated with intertidal mangrove prop roots, seagrass meadows, sandy beaches, and shoals. Among prop roots, specimens were significantly smaller and had highest densities (131 ind. m(-2)) between November and March. High organic matter in sediment and a relatively low predation rate seemed to support juvenile life among mangroves. Size and density analyses provided evidence that individuals gradually move to seagrass, sandy habitats, and shoals as they age. Specimens were significantly larger at a shoal (maximum radius R = 81 mm). New recruits were found between August and November in both 2008 and 2009. Timing of recruitment and population size frequencies confirmed a seasonal reproductive cycle. Juveniles had relatively high growth rates (2-7 mm month(-1)) and may reach an R of 20-25 mm after 1 year. Growth rates of larger specimens (R > 30 mm) were generally <2 mm month(-1). The activity pattern of A. typicus was related to the tidal phase and not to time of day: Specimens moved over the sediment surface during low tides and were burrowed during high tides possibly avoiding predation. This is one of the first studies to document an ontogenetic habitat shift for sea stars and provides new biological information as a basis for management of harvested A. typicus populations. PMID:24391259

  20. Burrows of the semi-terrestrial crab Ucides cordatus enhance CO2 release in a North Brazilian mangrove forest.

    PubMed

    Pülmanns, Nathalie; Diele, Karen; Mehlig, Ulf; Nordhaus, Inga

    2014-01-01

    Ucides cordatus is an abundant mangrove crab in Brazil constructing burrows of up to 2 m depth. Sediment around burrows may oxidize during low tides. This increase in sediment-air contact area may enhance carbon degradation processes. We hypothesized that 1) the sediment CO2 efflux rate is greater with burrows than without and 2) the reduction potential in radial profiles in the sediment surrounding the burrows decreases gradually, until approximating non-bioturbated conditions. Sampling was conducted during the North Brazilian wet season at neap tides. CO2 efflux rates of inhabited burrows and plain sediment were measured with a CO2/H2O gas analyzer connected to a respiration chamber. Sediment redox potential, pH and temperature were measured in the sediment surrounding the burrows at horizontal distances of 2, 5, 8 and 15 cm at four sediment depths (1, 10, 30 and 50 cm) and rH values were calculated. Sediment cores (50 cm length) were taken to measure the same parameters for plain sediment. CO2 efflux rates of plain sediment and individual crab burrows with entrance diameters of 7 cm were 0.7-1.3 µmol m(-2) s(-1) and 0.2-0.4 µmol burrows(-1) s(-1), respectively. CO2 released from a Rhizophora mangle dominated forest with an average of 1.7 U. cordatus burrows(-1) m(-2) yielded 1.0-1.7 µmol m(-2) s(-1), depending on the month and burrow entrance diameter. Laboratory experiments revealed that 20-60% of the CO2 released by burrows originated from crab respiration. Temporal changes in the reduction potential in the sediment surrounding the burrows did not influence the CO2 release from burrows. More oxidized conditions of plain sediment over time may explain the increase in CO2 release until the end of the wet season. CO2 released by U. cordatus and their burrows may be a significant pathway of CO2 export from mangrove sediments and should be considered in mangrove carbon budget estimates. PMID:25313661

  1. Seagrass as the main food source of Neaxius acanthus (Thalassinidea: Strahlaxiidae), its burrow associates, and of Corallianassa coutierei (Thalassinidea: Callianassidae)

    NASA Astrophysics Data System (ADS)

    Kneer, Dominik; Asmus, Harald; Vonk, Jan Arie

    2008-09-01

    Burrows of the thalassinidean shrimps Neaxius acanthus and Corallianassa coutierei are striking aspects in tropical seagrass beds of the Spermonde Archipelago, Indonesia. Burrow construction, behaviour, burrow type and associated commensal community were investigated to clarify the ecological role and food requirements of these shrimps and their commensals. Gut content analysis and stable-isotope data were used to unravel the food sources and the trophic interactions among the commensal community. Individuals of Neaxius acanthus were caught on Bone Batang Island. In narrow aquaria filled with sediment they constructed burrows resembling those found in the field. During burrow construction and maintenance only little sediment was brought to the surface, most was sorted and compacted to create a distinct lining. Maintenance work by single shrimps typically took about 5 min, after which the shrimp walked up to the entrance and rested for a similar period of time. There were no differences in behaviour between day and night. Intrasexual encounters inside the burrow were characterised by a high level of aggression and all resulted in one participant being driven out of the burrow. Intersexual encounters led to coexistence with both animals taking turns in burrow maintenance and guarding the entrance. Offered seagrass leaves were pulled underground, cut into pieces and eventually integrated into the lining. Burrows of Corallianassa coutierei resembled a deep U-shape. Chambers branching off halfway down and at the deepest point contained seagrass fragments. All steep parts of the burrow were lined similar to burrows of N. acanthus. No commensals were found associated with Corallianassa coutierei. However, burrows of Neaxius acanthus in the field typically contained a pair of shrimps, up to 8 individuals of the commensal bivalve Barrimysia cumingii and large numbers of gammarid amphipods. Other animals found associated with the burrow were the goby Austrolethops wardi, a

  2. Nelson's big horn sheep (Ovis canadensis nelsoni) trample Agassiz's desert tortoise (Gopherus agassizii) burrow at a California wind energy facility

    USGS Publications Warehouse

    Agha, Mickey; Delaney, David F.; Lovich, Jeffrey E.; Briggs, Jessica; Austin, Meaghan; Price, Steven J.

    2015-01-01

    Research on interactions between Agassiz's desert tortoises (Gopherus agassizii) and ungulates has focused exclusively on the effects of livestock grazing on tortoises and their habitat (Oldemeyer, 1994). For example, during a 1980 study in San Bernardino County, California, 164 desert tortoise burrows were assessed for vulnerability to trampling by domestic sheep (Ovis aries). Herds of grazing sheep damaged 10% and destroyed 4% of the burrows (Nicholson and Humphreys 1981). In addition, a juvenile desert tortoise was trapped and an adult male was blocked from entering a burrow due to trampling by domestic sheep. Another study found that domestic cattle (Bos taurus) trampled active desert tortoise burrows and vegetation surrounding burrows (Avery and Neibergs 1997). Trampling also has negative impacts on diversity of vegetation and intershrub soil crusts in the desert southwest (Webb and Stielstra 1979). Trampling of important food plants and overgrazing has the potential to create competition between desert tortoises and domestic livestock (Berry 1978; Coombs 1979; Webb and Stielstra 1979).

  3. Recruitment in Radiotherapy

    ERIC Educational Resources Information Center

    Deeley, T. J.; And Others

    1976-01-01

    The Faculty Board of Radiotherapy and Oncology of the Royal College of Radiobiologists surveyed the factors thought to influence recruitment into the specialty. Possible factors listed in replies of 36 questionnaires are offered. (LBH)

  4. SEASONAL FORAGING BY CHANNEL CATFISH ON TERRESTRIALLY BURROWING CRAYFISH IN A FLOODPLAIN-RIVER ECOSYSTEM

    EPA Science Inventory

    The seasonal use of terrestrially burrowing crayfish as a food item by channel catfish Ictalurus punctatus was studied in channelized and non-channelized sections of the Yockanookany River (Mississippi, USA). During seasonal inundation of the floodplains, the crayfish occupied o...

  5. Gopherus agassizii (desert tortoise) and Crotalus ruber (red diamond rattlesnake). Burrow co-occupancy

    USGS Publications Warehouse

    Lovich, Jeffrey E.

    2011-01-01

    I observed an adult Desert Tortoise and an adult Red Diamond Rattlesnake (sexes unknown) in a shallow tortoise burrow on 6 January 1997 at a wind energy generation facility near Palm Springs, Riverside Co., California, USA (33.9599°N, 116.6613°W).

  6. Strong population genetic structure and larval dispersal capability of the burrowing ghost shrimp (Neotrypaea californiensis)

    EPA Science Inventory

    The burrowing ghost shrimp, Neotrypaea californiensis, is a vital member of the estuarine benthic community. Dense populations of shrimp are found in the major estuaries of Washington and Oregon. Our study determines the genetic structure of shrimp populations in order to gain ...

  7. THE EFFECT OF MIREX ON THE BURROWING ACTIVITY OF THE LUGWORM ('ARENICOLA CRISTATA')

    EPA Science Inventory

    An inexpensive bioassay system was developed to estimate pollutant effects on a benthic animal. Mirex, a fire ant toxicant, was taken into the substrate by the burrowing and feeding activity of the lugworm, Arenicola cristata, and significantly affected this activity. Mirex was p...

  8. Living in a ``stethoscope'': burrow-acoustics promote auditory specializations in subterranean rodents

    NASA Astrophysics Data System (ADS)

    Lange, Simone; Burda, Hynek; Wegner, Regina E.; Dammann, Philip; Begall, Sabine; Kawalika, Mathias

    2007-02-01

    Subterranean mammals rely to a great extent on audition for communication and to be alerted to danger. The only hitherto published report on burrow acoustics revealed that in tunnels of blind mole-rats ( Spalax ehrenbergi), airborne sounds of 440 Hz propagated best whereas lower and higher frequencies were effectively attenuated. Morpho-functional analyses classify the ear of subterranean mammals as a low-sensitivity and low-frequency device. Concordantly, hearing is characterized by low sensitivity and a restricted frequency range tuned to low frequencies (0.5-4 kHz). Some authors considered the restricted hearing in subterranean mammals vestigial and degenerate due to under-stimulation. In contrast to this view stand a rich (mostly low-frequency) vocal repertoire and progressive structural specializations of the middle and inner ear. Thus, other authors considered these hearing characteristics adaptive. To test the hypothesis that acoustical environment in burrows of different species of subterranean mammals is similar, we measured sound attenuation in burrows of Fukomys mole-rats (formerly known as Cryptomys, cf. Kock et al. 2006) of two differently sized species at different locations in Zambia. We show that in these burrows, low-frequency sounds (200-800 Hz) are not only least attenuated but also their amplitude may be amplified like in a stethoscope (up to two times over 1 m). We suggest that hearing sensitivity has decreased during evolution of subterranean mammals to avoid over-stimulation of the ear in their natural environment.

  9. [Suicidal burrowing behavior--a special kind of the "hide-and-die-syndrome"].

    PubMed

    Hartwig, Sven; Tsokos, Michael

    2007-01-01

    When the situation at a death scene is unusual, this may suggest the involvement of another person. On the other hand, one also has to consider the possibility of a conscious or unconscious behavior in connection with extreme stress situations or suicidal acts. The forensic findings and criminalistic reconstruction of two cases of suicidal burrowing behavior are presented and discussed. PMID:18260568

  10. The influence of small-mammal burrowing activity on water storage at the Hanford Site

    SciTech Connect

    Landeen, D.S.

    1994-12-31

    This paper summarizes the activities that were conducted in support of the long-term surface barrier development program by Westinghouse Hanford Company to determine the degree that small-mammal burrow systems affect the loss or retention of water in the soils at the Hanford Site in Washington state. An animal intrusion lysimeter facility was constructed, consisting of two outer boxes buried at grade, which served as receptacles for six animal intrusion lysimeters. Small burrowing animals common the Hanford Site were introduced over a 3- to 4-month period. Supplemental precipitation was added monthly to three of the lysimeters with a rainfall simulator (rainulator). Information collected from the five tests indicated that (1) during summer months, water was lost in all the lysimeters, including the supplemental precipitation added with the rainulator; and (2) during winter months, all lysimeters gained water. The data indicate little difference in the amount of water stored between control and animal lysimeters. The overall water loss was attributed to surface evaporation, a process that occurred equally in control and treatment lysimeters. Other causes of water loss are a result of (1) constant soil turnover and subsequent drying, and (2) burrow ventilation effects. This suggests that burrow systems will not contribute to any significant water storage at depth and, in fact, may enhance the removal of water from the soil.

  11. Complete Genome Sequence of a Bohle iridovirus Isolate from Ornate Burrowing Frogs (Limnodynastes ornatus) in Australia.

    PubMed

    Hick, Paul M; Subramaniam, Kuttichantran; Thompson, Patrick; Whittington, Richard J; Waltzek, Thomas B

    2016-01-01

    Bohle iridovirus (BIV) is a species within the genus Ranavirus, family Iridoviridae, first isolated from the ornate burrowing frog Limnodynastes ornatus in Australia. The BIV genome confirms it is closely related to isolates from boreal toad Anaxyrus boreas and leaf-tailed gecko Uroplatus fimbriatus within the United States and Germany, respectively. PMID:27540051

  12. Complete Genome Sequence of a Bohle iridovirus Isolate from Ornate Burrowing Frogs (Limnodynastes ornatus) in Australia

    PubMed Central

    Thompson, Patrick; Whittington, Richard J.; Waltzek, Thomas B.

    2016-01-01

    Bohle iridovirus (BIV) is a species within the genus Ranavirus, family Iridoviridae, first isolated from the ornate burrowing frog Limnodynastes ornatus in Australia. The BIV genome confirms it is closely related to isolates from boreal toad Anaxyrus boreas and leaf-tailed gecko Uroplatus fimbriatus within the United States and Germany, respectively. PMID:27540051

  13. The Potential Use of Electricity to Control Burrowing Shrimp in Oyster Aquaculture Beds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thalassinid shrimp cause significant problems for oyster aquaculture in the Pacific Northwest (USA) where oysters succumb to the physical disruption of the sediment by the burrowing activity of these animals. While electrofishing is a commonly used technique to capture fish and some invertebrates i...

  14. Sedimentary organic matter distributions, burrowing activity, and biogeochemical cycling: Natural patterns and experimental artifacts

    NASA Astrophysics Data System (ADS)

    Michaud, Emma; Aller, Robert, C.; Stora, Georges

    2010-11-01

    The coupling between biogenic reworking activity and reactive organic matter patterns within deposits is poorly understood and often ignored. In this study, we examined how common experimental treatments of sediment affect the burrowing behavior of the polychaete Nephtys incisa and how these effects may interact with reactive organic matter distributions to alter diagenetic transport - reaction balances. Sediment and animals were recovered from a subtidal site in central Long Island Sound, USA. The upper 15 cm of the sediment was sectioned into sub-intervals, and each interval separately sieved and homogenized. Three initial distributions of sediment and organic substrate reactivity were setup in a series of microcosms: (1) a reconstituted natural pattern with surface-derived sediment overlying sediment obtained from progressively deeper material to a depth of 15 cm (Natural); (2) a 15 cm thick sediment layer composed only of surface-derived sediment (Rich); and (3) a 15 cm thick layer composed of uniformally mixed sediment from the original 15 cm sediment profile (Averaged). The two last treatments are comparable to that used in microcosms in many previous studies of bioturbation and interspecific functional interaction experiments. Sediment grain size distributions were 97.5% silt-clay and showed no depth dependent patterns. Sediment porosity gradients were slightly altered by the treatments. Nepthys were reintroduced and aquariums were X-rayed regularly over 5 months to visualize and quantify spatial and temporal dynamics of burrows. The burrowing behaviour of adult populations having similar total biovolume, biomass, abundance, and individual sizes differed substantially as a function of treatment. Burrows in sediment with natural property gradients were much shallower and less dense than those in microcosms with altered gradients. The burrow volume/biovolume ratio was also lower in the substrate with natural organic reactivity gradients. Variation in food

  15. The effect of mayfly (Hexagenia spp.) burrowing activity on sediment oxygen demand in western Lake Erie

    USGS Publications Warehouse

    Edwards, William J.; Soster, Frederick M.; Matisoff, Gerald; Schloesser, Donald W.

    2009-01-01

    Previous studies support the hypothesis that large numbers of infaunal burrow-irrigating organisms in the western basin of Lake Erie may increase significantly the sediment oxygen demand, thus enhancing the rate of hypolimnetic oxygen depletion. We conducted laboratory experiments to quantify burrow oxygen dynamics and increased oxygen demand resulting from burrow irrigation using two different year classes of Hexagenia spp. nymphs from western Lake Erie during summer, 2006. Using oxygen microelectrodes and hot film anemometry, we simultaneously determined oxygen concentrations and burrow water flow velocities. Burrow oxygen depletion rates ranged from 21.7 mg/nymph/mo for 15 mm nymphs at 23 °C to 240.7 mg/nymph/mo for 23 mm nymphs at 13 °C. Sealed microcosm experiments demonstrated that mayflies increase the rate of oxygen depletion by 2-5 times that of controls, depending on size of nymph and water temperature, with colder waters having greater impact. At natural population densities, nymph pumping activity increased total sediment oxygen demand 0.3-2.5 times compared to sediments with no mayflies and accounted for 22-71% of the total sediment oxygen demand. Extrapolating laboratory results to the natural system suggest that Hexagenia spp. populations may exert a significant control on oxygen depletion during intermittent stratification. This finding may help explain some of the fluctuations in Hexagenia spp. population densities in western Lake Erie and suggests that mayflies, by causing their own population collapse irrespective of other environmental conditions, may need longer term averages when used as a bio-indicator of the success of pollution-abatement programs in western Lake Erie and possibly throughout the Great Lakes.

  16. Burrow limitations and group living in the communally rearing rodent, Octodon degus

    PubMed Central

    Ebensperger, Luis A.; Chesh, Adrian S.; Castro, Rodrigo A.; Tolhuysen, Liliana Ortiz; Quirici, Verónica; Burger, Joseph Robert; Sobrero, Raúl; Hayes, Loren D.

    2012-01-01

    Group living is thought to evolve whenever individuals attain a net fitness advantage due to reduced predation risk or enhanced foraging efficiency, but also when individuals are forced to remain in groups, which often occurs during high-density conditions due to limitations of critical resources for independent breeding. The influence of ecological limitations on sociality has been studied little in species in which reproduction is more evenly shared among group members. Previous studies in the caviomorph rodent Octodon degus (a New World hystricognath) revealed no evidence that group living confers an advantage and suggest that burrow limitations influence formation of social groups. Our objective was to examine the relevance of ecological limitations on sociality in these rodents. Our 4-year study revealed no association between degu density and use of burrow systems. The frequency with which burrow systems were used by degus was not related to the quality of these structures; only in 1 of the 4 years did the frequency of burrow use decrease with decreasing abundance of food. Neither the number of females per group nor total group size (related measures of degu sociality) changed with yearly density of degus. Although the number of males within social groups was lower in 2008, this variation was not related clearly to varying density. The percentage of females in social groups that bred was close to 99% and did not change across years of varying density. Our results suggest that sociality in degus is not the consequence of burrow limitations during breeding. Whether habitat limitations contribute to variation in vertebrate social systems is discussed. PMID:22328789

  17. Spatial and Temporal Oxygen Dynamics in Macrofaunal Burrows in Sediments: A Review of Analytical Tools and Observational Evidence

    PubMed Central

    Satoh, Hisashi; Okabe, Satoshi

    2013-01-01

    The availability of benthic O2 plays a crucial role in benthic microbial communities and regulates many important biogeochemical processes. Burrowing activities of macrobenthos in the sediment significantly affect O2 distribution and its spatial and temporal dynamics in burrows, followed by alterations of sediment microbiology. Consequently, numerous research groups have investigated O2 dynamics in macrofaunal burrows. The introduction of powerful tools, such as microsensors and planar optodes, to sediment analysis has greatly enhanced our ability to measure O2 dynamics in burrows at high spatial and temporal resolution with minimal disturbance of the physical structure of the sediment. In this review, we summarize recent studies of O2-concentration measurements in burrows with O2 microsensors and O2 planar optodes. This manuscript mainly focuses on the fundamentals of O2 microsensors and O2 planar optodes, and their application in the direct measurement of the spatial and temporal dynamics of O2 concentrations in burrows, which have not previously been reviewed, and will be a useful supplement to recent literature reviews on O2 dynamics in macrofaunal burrows. PMID:23594972

  18. Evaluation of insecticide impregnated baits for control of mosquito larvae in land crab burrows on French Polynesian atolls.

    PubMed

    Lardeux, Frederic; Sechan, Yves; Faaruia, Marc

    2002-07-01

    Land crab burrows are larval mosquito habitats of major significance in the Pacific region. They are constituted by a sinuous tunnel leading to a chamber in contact with the water table, where mosquito larvae proliferate. Controlling larvae in these sites is difficult, because the configuration of burrows prevents the use of standard techniques. An experiment was carried out in French Polynesia to control Aedes polynesiensis Marks and Culex spp. breeding in burrows of the land crab Cardisoma carnifex (Herbst). The technique was based on the crab's behavior, which involves the crab carrying food into its burrow. It was shown that appetizing baits impregnated with an insecticide were carried by crabs into the flooded chamber of their burrows. A field treatment of burrows was carried out by sowing insecticide impregnated baits on the ground. The treatment coverage was almost perfect and the easy implementation of the technique enabled large areas to be treated in a short time. The bait was developed by compacting various flours, which easily incorporate a large variety of insecticide formulations. Although the baits can be easily stocked, a reliable insecticide is still to be found. The results indicate that our technique could be a method of choice for treating crab burrows. PMID:12144299

  19. Characterization of specificity of bacterial community structure within the burrow environment of the marine polychaete Hediste (Nereis) diversicolor.

    PubMed

    Pischedda, Laura; Militon, Cécile; Gilbert, Franck; Cuny, Philippe

    2011-12-01

    Bioturbation is known to stimulate microbial communities, especially in macrofaunal burrows where the abundance and activities of bacteria are increased. Until now, these microbial communities have been poorly characterized and an important ecological question remains: do burrow walls harbor similar or specific communities compared with anoxic and surface sediments? The bacterial community structure of coastal sediments inhabited by the polychaete worm Hediste diversicolor was investigated. Surface, burrow wall and anoxic sediments were collected at the Carteau beach (Gulf of Fos, Mediterranean Sea). Bacterial diversity was determined by analyzing small subunit ribosomal RNA (16S rRNA) sequences from three clone libraries (168, 179 and 129 sequences for the surface, burrow wall and anoxic sediments, respectively). Libraries revealed 306 different operational taxonomic units (OTUs) belonging to at least 15 bacterial phyla. Bioinformatic analyses and comparisons between the three clone libraries showed that the burrow walls harbored a specific bacterial community structure which differed from the surface and anoxic environments. More similarities were nevertheless found with the surface assemblage. Inside the burrow walls, the bacterial community was characterized by high biodiversity, which probably results from the biogeochemical heterogeneity of the burrow system. PMID:21946148

  20. Burrows of the Semi-Terrestrial Crab Ucides cordatus Enhance CO2 Release in a North Brazilian Mangrove Forest

    PubMed Central

    Pülmanns, Nathalie; Diele, Karen; Mehlig, Ulf; Nordhaus, Inga

    2014-01-01

    Ucides cordatus is an abundant mangrove crab in Brazil constructing burrows of up to 2 m depth. Sediment around burrows may oxidize during low tides. This increase in sediment-air contact area may enhance carbon degradation processes. We hypothesized that 1) the sediment CO2 efflux rate is greater with burrows than without and 2) the reduction potential in radial profiles in the sediment surrounding the burrows decreases gradually, until approximating non-bioturbated conditions. Sampling was conducted during the North Brazilian wet season at neap tides. CO2 efflux rates of inhabited burrows and plain sediment were measured with a CO2/H2O gas analyzer connected to a respiration chamber. Sediment redox potential, pH and temperature were measured in the sediment surrounding the burrows at horizontal distances of 2, 5, 8 and 15 cm at four sediment depths (1, 10, 30 and 50 cm) and rH values were calculated. Sediment cores (50 cm length) were taken to measure the same parameters for plain sediment. CO2 efflux rates of plain sediment and individual crab burrows with entrance diameters of 7 cm were 0.7–1.3 µmol m−2 s−1 and 0.2–0.4 µmol burrows−1 s−1, respectively. CO2 released from a Rhizophora mangle dominated forest with an average of 1.7 U. cordatus burrows−1 m−2 yielded 1.0–1.7 µmol m−2 s−1, depending on the month and burrow entrance diameter. Laboratory experiments revealed that 20–60% of the CO2 released by burrows originated from crab respiration. Temporal changes in the reduction potential in the sediment surrounding the burrows did not influence the CO2 release from burrows. More oxidized conditions of plain sediment over time may explain the increase in CO2 release until the end of the wet season. CO2 released by U. cordatus and their burrows may be a significant pathway of CO2 export from mangrove sediments and should be considered in mangrove carbon budget estimates. PMID:25313661

  1. Crayfish fossil burrows, a key tool for identification of terrestrial environments in tide-dominated sequence, Upper Eocene, Sirt Basin, Libya

    NASA Astrophysics Data System (ADS)

    Abouessa, Ashour; Duringer, Philippe; Schuster, Mathieu; Pelletier, Jonathan

    2015-11-01

    The majority of decapod crustaceans are defined as marine organisms. Crayfish are one of the relatively few known exceptions. They are freshwater-environment adapted decapods that build characteristically large, simple and branched cylindrical morphotype traces in fluvial plains. Their burrows bear lots of special features that make them different from other burrows. Consequently, the identification of true crayfish burrows in the sedimentary record is crucial for the interpretation of depositional environment. The studied interval (45 m thick, exposed in the Dur At Talah escarpment southern Sirt Basin; Fig. 1) represents a case-study which is previously believed to be purely tidal. In this interval, the identification of the crayfish burrows provides a reliable tool for distinguishing terrestrial environments. The crayfish burrows of Dur At Talah are characterized by dimensional, morphological, and especially behavioral aspects that combined, cannot be ascribed to another burrow makers. Essential criteria used to attribute these burrows to the crayfish include: Their length (the depth of penetration into the sediments), their regularly circular cross-sectional area, the presence of mid-way enlargement chamber along the burrow vertical axis, as well as the subtle preservation of the burrow chimney. More importantly, these morphological features allow the recognition of some of the crayfish diagnostic behavioral habits. Most significant of these is the one deduced from the interaction of the burrow with the seasonal fluctuation of the paleo groundwater level. Supplementary indications that restrict the studied burrows to terrestrial organism include their occurrences within pedogenically altered strata that bear evident features of prolonged emersion. Of these features, mud cracks and burrows that are filled with continental fossil are the clearest. Few horizons with termite fungus comb are also distinguishable. Although other burrows of the classically known

  2. Researching participant recruitment times.

    PubMed

    O'Brien, Rachel; Black, Polly

    2015-11-01

    Conducting research in emergency departments is relatively new, and there are a number of ethical and practical challenges to recruiting patients in these settings. In 2008, the Emergency Medicine Research Group Edinburgh (EMERGE) was set up at the Royal Infirmary of Edinburgh emergency department to support researchers and encourage the growth of research in emergency medicine. As part of a review of their working methods, the group's clinical nurse researchers undertook a small study to identify participant recruitment times. The results showed a significant difference between perceived and actual recruitment times, which has implications for planning staff numbers and budgets. This article describes the evaluation process and methods of data collection, and discusses the results. PMID:26542924

  3. eHealth Recruitment Challenges

    ERIC Educational Resources Information Center

    Thompson, Debbe; Canada, Ashanti; Bhatt, Riddhi; Davis, Jennifer; Plesko, Lisa; Baranowski, Tom; Cullen, Karen; Zakeri, Issa

    2006-01-01

    Little is known about effective eHealth recruitment methods. This paper presents recruitment challenges associated with enrolling African-American girls aged 8-10 years in an eHealth obesity prevention program, their effect on the recruitment plan, and potential implications for eHealth research. Although the initial recruitment strategy was…

  4. DISTRIBUTION AND ABUNDANCE OF BURROWING SHRIMP IN TWO OREGON ESTUARIES AND IMPLICATIONS FOR ESTUARINE-SCALE NITROGEN DYNAMICS

    EPA Science Inventory

    Thalassinid burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) inhabit large expanses of Pacific estuarine tide flats, from British Columbia to Baja California. The spatial distribution of shrimp populations within estuaries has rarely been quantified because ...

  5. Recruiting Adult Education Students.

    ERIC Educational Resources Information Center

    Learning Resources Network, Manhattan, KS.

    This document is the first nationwide compilation of successful recruiting techniques for students in adult basic education, literacy, General Educational Development classes, and adult high school degree programs. Information for the publication was gathered from a literature search and other sources, especially "Reaching the Least Educated," a…

  6. Graduate Student Recruitment.

    ERIC Educational Resources Information Center

    Baron, Patricia B.

    1987-01-01

    A study of graduate student recruitment practices was conducted in the spring of 1986 to determine the current practice of graduate schools and to determine the extent to which they are using marketing techniques. The members of the Council of Graduate Schools were surveyed; 250 graduate schools responded (69% response rate). Questions concerned…

  7. Today's Recruitment Trends.

    ERIC Educational Resources Information Center

    Sugarman, Joe

    1996-01-01

    Five trends in the creation of college student recruitment publications are identified: (1) using market research and marketing principles; (2) targeting specific groups; (3) honesty about campus personality and reputation; (4) cost-effectiveness; and (5) creativity in using effective copy and design. (MSE)

  8. Recruitment and Information Program

    ERIC Educational Resources Information Center

    Liebergott, Harvey

    1976-01-01

    The Bureau of Education for the Handicapped's Recruitment and Information Program provides parents and other interested individuals with information on the educational needs of handicapped children through such activities as the National Information Center for the Handicapped ("Closer Look"), pamphlets on various subjects, and media campaigns that…

  9. Recruiting Seminary Trustees.

    ERIC Educational Resources Information Center

    Warford, Malcolm

    1985-01-01

    The important role played by trustees of seminaries and the recruitment of these leaders are considered. The serious financial problems facing the board of directors has focused attention on the role and scope of seminary trusteeship. Leadership is needed by trustees to address issues of declining enrollments, curricula that address theological…

  10. Predator nonconsumptive effects on prey recruitment weaken with recruit density.

    PubMed

    Ellrich, Julius A; Scrosati, Ricardo A; Molis, Markus

    2015-03-01

    We investigated the nonconsumptive effects (NCEs) of predatory dogwhelks (Nucella lapillus) on intertidal barnacle (Semibalanus balanoides) recruitment through field experiments on the Gulf of St. Lawrence coast and the Atlantic coast of Nova Scotia, Canada. We studied the recruitment seasons (May-June) of 2011 and 2013. In 2011, the Gulf coast had five times more nearshore phytoplankton (food for barnacle larvae and recruits) during the recruitment season and yielded a 58% higher barnacle recruit density than the Atlantic coast at the end of the recruitment season. In 2013, phytoplankton levels and barnacle recruit density were similar on both coasts and also lower than for the Gulf coast in 2011. Using the comparative-experimental method, the manipulation of dogwhelk presence (without allowing physical contact with prey) revealed that dogwhelk cues limited barnacle recruitment under moderate recruit densities (Atlantic 2011/2013 and Gulf 2013) but had no effect under a high recruit density (Gulf 2011). Barnacle recruits attract settling larvae through chemical cues. Thus, the highest recruit density appears to have neutralized dogwhelk effects. This study suggests that the predation risk perceived by settling larvae may decrease with increasing recruit density and that prey food supply may indirectly influence predator NCEs on prey recruitment. PMID:26236858

  11. Black-footed ferrets and recreational shooting influence the attributes of black-tailed prairie dog burrows

    USGS Publications Warehouse

    Biggins, Dean E.; Ramakrishnan, Shantini; Goldberg, Amanda R.; Eads, David A.

    2012-01-01

    Black-tailed prairie dogs (Cynomys ludovicianus) plug burrows occupied by black-footed ferrets (Mustela nigripes), and they also plug burrows to entomb dead prairie dogs. We further evaluated these phenomena by sampling connectivity and plugging of burrow openings on prairie dog colonies occupied by ferrets, colonies where recreational shooting was allowed, and colonies with neither shooting nor ferrets. We counted burrow openings on line surveys and within plots, classified surface plugging, and used an air blower to examine subsurface connectivity. Colonies with ferrets had lower densities of openings, fewer connected openings (suggesting increased subsurface plugging), and more surface plugs compared to colonies with no known ferrets. Colonies with recreational shooting had the lowest densities of burrow openings, and line-survey data suggested colonies with shooting had intermediate rates of surface plugging. The extent of surface and subsurface plugging could have consequences for the prairie dog community by changing air circulation and escape routes of burrow systems and by altering energetic relationships. Burrow plugging might reduce prairie dogs' risk of predation by ferrets while increasing risk of predation by American badgers (Taxidea taxus); however, the complexity of the trade-off is increased if plugging increases the risk of predation on ferrets by badgers. Prairie dogs expend more energy plugging and digging when ferrets or shooting are present, and ferrets increase their energy expenditures when they dig to remove those plugs. Microclimatic differences in plugged burrow systems may play a role in flea ecology and persistence of the flea-borne bacterium that causes plague (Yersinia pestis).

  12. Effect of Burrowing Mammals on the Hydrology of a Drained Riparian Ecosystem

    NASA Astrophysics Data System (ADS)

    Cassidy, J.; Dragila, M. I.

    2002-12-01

    Agricultural pollutants and excess nutrients are transported by surface and subsurface fluvial mechanisms. Diffusive transport provides significant breakdown and processing of excess nutrients before reaching water resources and ecologically sensitive habitats. However, some quantity of contaminants will bypass the system. This study quantifies the effect of burrowing fossorial mammals, specifically voles (Microtini), on the hydrology of a drained riparian agricultural ecosystem. Animal burrows, surface features and tunnel structures are found to play a significant role in nutrient transport, which is currently unaccounted for by land managers. Furthermore, the proximity of features created by microtini rodents to agricultural tile drainage systems commonly associated with bottomland perennial agriculture may have important implications for land management of water quality. The presence of these features may require an adjustment in our understanding of drainage network behavior.

  13. Relating divergence in polychaete musculature to different burrowing behaviors: a study using opheliidae (Annelida).

    PubMed

    Law, Chris J; Dorgan, Kelly M; Rouse, Greg W

    2014-05-01

    Divergent morphologies among related species are often correlated with distinct behaviors and habitat uses. Considerable morphological and behavioral differences are found between two major clades within the polychaete family Opheliidae. For instance, Thoracophelia mucronata burrows by peristalsis, whereas Armandia brevis exhibits undulatory burrowing. We investigate the anatomical differences that allow for these distinct burrowing behaviors, then interpret these differences in an evolutionary context using broader phylogenetic (DNA-based) and morphological analyses of Opheliidae and taxa, such as Scalibregmatidae and Polygordiidae. Histological three-dimensional-reconstruction of A. brevis reveals bilateral longitudinal muscle bands as the prominent musculature of the body. Circular muscles are absent; instead oblique muscles act with unilateral contraction of longitudinal muscles to bend the body during undulation. The angle of helical fibers in the cuticle is consistent with the fibers supporting turgidity of the body rather than resisting radial expansion from longitudinal muscle contraction. Circular muscles are present in the anterior of T. mucronata, and they branch away from the body wall to form oblique muscles. Helical fibers in the cuticle are more axially oriented than those in undulatory burrowers, facilitating radial expansion during peristalsis. A transition in musculature accompanies the change in external morphology from the thorax to the abdomen, which has oblique muscles similar to A. brevis. Muscles in the muscular septum, which extends posteriorly to form the injector organ, act in synchrony with the body wall musculature during peristalsis: they contract to push fluid anteriorly and expand the head region following a direct peristaltic wave of the body wall muscles. The septum of A. brevis is much thinner and is presumably used for eversion of a nonmuscular pharynx. Mapping of morphological characters onto the molecular-based phylogeny shows

  14. Impaired burrowing is the most prominent behavioral deficit of aging htau mice.

    PubMed

    Geiszler, Philippine Camilla; Barron, Matthew Richard; Pardon, Marie-Christine

    2016-08-01

    htau mice are deficient of murine tau but express all six human tau isoforms, leading to gradual tau misprocessing and aggregation in brain areas relevant to Alzheimer's disease. While histopathological changes in htau mice have been researched in the past, we focused here on functional consequences of human tau accumulation. htau mice and their background controls - murine tau knock-out (mtau(-/-)) and C57Bl/6J mice - underwent a comprehensive trial battery to investigate species-specific behavior, locomotor activity, emotional responses, exploratory traits, spatial and recognition memory as well as acquisition, retention and extinction of contextual fear at two, four, six, nine and twelve months of age. In htau mice, tau pathology was already present at two months of age, whereas deficits in food burrowing and spatial working memory were first noted at four months of age. At later stages the presence of human tau on a mtau(-/-) background appeared to guard cognitive performance; as mtau(-/-) but not htau mice differed from C57Bl/6J mice in the food burrowing, spontaneous alternation and object discrimination tasks. Aging mtau(-/-) mice also exhibited increased body mass and locomotor activity. These data highlight that reduced food-burrowing performance was the most robust aspect of the htau phenotype with aging. htau and mtau(-/-) deficits in food burrowing pointed at the necessity of intact tau systems for daily life activities. While some htau and mtau(-/-) deficits overlap, age differences between the two genotypes may reflect distinct functional effects and compared to C57Bl/6J mice, the htau phenotype appeared stronger than the mtau(-/-) phenotype at young ages but milder with aging. PMID:27167086

  15. Long-term population dynamics of a managed burrowing owl colony

    USGS Publications Warehouse

    Barclay, John H.; Korfanta, Nicole M.; Kauffman, Matthew J.

    2011-01-01

    We analyzed the population dynamics of a burrowing owl (Athene cunicularia) colony at Mineta San Jose International Airport in San Jose, California, USA from 1990-2007. This colony was managed by using artificial burrows to reduce the occurrence of nesting owls along runways and within major airport improvement projects during the study period. We estimated annual reproduction in natural and artificial burrows and age-specific survival rates with mark-recapture techniques, and we estimated the relative contribution of these vital rates to population dynamics using a life table response experiment. The breeding colony showed 2 distinct periods of change: high population growth from 7 nesting pairs in 1991 to 40 pairs in 2002 and population decline to 17 pairs in 2007. Reproduction was highly variable: annual nesting success (pairs that raised =1 young) averaged 79% and ranged from 36% to 100%, whereas fecundity averaged 3.36 juveniles/pair and ranged from 1.43 juveniles/pair to 4.54 juveniles/pair. We estimated annual adult survival at 0.710 during the period of colony increase from 1996 to 2001 and 0.465 during decline from 2002 to 2007, but there was no change in annual survival of juveniles between the 2 time periods. Long-term population growth rate (lambda) estimated from average vital rates was lambdaa=1.072 with lambdai=1.288 during colony increase and lambdad=0.921 (DELTA lambda=0.368) during decline. A life table response experiment showed that change in adult survival rate during increasing and declining phases explained more than twice the variation in growth rate than other vital rates. Our findings suggest that management and conservation of declining burrowing owl populations should address factors that influence adult survival.

  16. Animal behaviour: use of dung as a tool by burrowing owls.

    PubMed

    Levey, Douglas J; Duncan, R Scot; Levins, Carrie F

    2004-09-01

    Reports of tool usage by birds tend to be anecdotal as only a few individuals may be involved and the behaviour observed can often be interpreted in other ways. Here we describe the widespread collection of mammalian dung by burrowing owls (Athene cunicularia) and show that they use this dung as a bait to attract dung beetles, a major item of prey. Our controlled investigation provides an unambiguous estimate of the importance of tool use in a wild animal. PMID:15343324

  17. Physicochemical and Microbial Properties of Burrows of the Deposit-feeding Thalassinidean Ghost Shrimp Biffarius arenosus (Decapoda: Callianassidae)

    NASA Astrophysics Data System (ADS)

    Bird, F. L.; Boon, P. I.; Nichols, P. D.

    2000-09-01

    The physicochemical and microbial properties of the burrows of Biffarius arenosus, a ghost shrimp common in temperate south-eastern Australia, were investigated and shown to be more similar to the surface sediments than to the surrounding subsurface sediments. The burrow walls had a similar organic carbon content to that of the surrounding sediment, a result which was consistent with their lack of a discrete mucous lining. Burrow walls, however, were lined with compacted and smoothed sediment and were coloured a distinct light yellow/brown compared with the dark grey of the surrounding subsurface sediments. Moderately reducing redox conditions were found in both the burrow wall and surface sediment (means 213 mV and 243 mV, respectively), indicative of a burrow environment regularly flushed with overlying water by the resident shrimp. Microbial activity (measured as fluorescein diacetate hydrolysis) in the burrow walls was higher than in the surrounding sediments, but there were no significant differences across sediment types in bacterial abundances (epifluorescence microscopy total counts, using DAPI) or in microbial biomasses (total phospholipid contents). Biomarker analysis of the phospholipid fatty acid (PLFA) profiles indicated that bacteria dominated the benthic community (˜80% of total PLFAs), and showed the presence of both aerobic and anaerobic bacteria in all sediment samples.

  18. The importance of burrowing, climbing and standing upright for laboratory rats

    PubMed Central

    Weary, Daniel M.

    2016-01-01

    Standard laboratory cages prevent rats (Rattus norvegicus) from performing many behaviours that they perform in the wild, but little is known about how this may affect their welfare. The aims of this study were (i) to record the propensity to burrow, climb and stand upright in 3-, 8- and 13-month old laboratory rats housed in semi-naturalistic environments and (ii) to compare the frequency of lateral stretching in semi-naturalistic versus standard-housed rats; we predicted standard-housed rats would perform more lateral stretches to compensate for the inability to stretch upright. Rats' propensity to burrow remained constant as they aged (approx. 30 bouts per day totalling 20–30 min), suggesting burrowing is important to rats. Climbing decreased from 76 to 7 bouts per day at 3 versus 13 months, probably because of declining physical ability. Upright standing decreased from 178 to 73 bouts per day, but continued to be frequently expressed even in older rats. Standard-housed rats stretched much more frequently than semi-naturalistic-housed rats (53 versus 6 bouts per day at 13 months), perhaps in compensation for inability to stretch upright and to relieve stiffness caused by low mobility associated with standard housing. These findings suggest that standard laboratory cages interfere with important natural behaviours, which is likely to compromise rat welfare. PMID:27429772

  19. Regional and Seasonal Diet of the Western Burrowing Owl in South-Central Nevada

    SciTech Connect

    Derek B. Hall, Paul D. Greger, Jeffrey R. Rosier

    2009-04-01

    We examined diets of Western Burrowing Owls (Athene cunicularia hypugaea) based on contents of pellets and large prey remains collected year-round at burrows in each of the 3 regions in south central Nevada (Mojave Desert, Great Basin Desert, and Transition region). The most common prey items, based on percent frequency of occurrence, were crickets and grasshoppers, beetles, rodents, sun spiders, and scorpions. The most common vertebrate prey was kangaroo rats (Dipodomys spp.). True bugs (Hemiptera), scorpions, and western harvest mice (Reithrodontomys megalotis) occurred most frequently in pellets from the Great Basin Desert region. Kangaroo rats (Dipodomys spp.) and pocket mice (Perognathinae) were the most important vertebrate prey items in the Transition and Mojave Desert regions, respectively. Frequency of occurrence of any invertebrate prey was high (>80%) in samples year-round but dropped in winter samples, with scorpions and sun spiders exhibiting the steepest declines. Frequency of occurrence of any vertebrate prey peaked in spring samples, was intermediate for winter and summer samples, and was lowest in fall samples. With the possible exception of selecting for western harvest mice in the Great Basin Desert region, Western Burrowing Owls in our study appeared to be opportunistic foragers with a generalist feeding strategy.

  20. Carpal-metacarpal specializations for burrowing in South American octodontoid rodents.

    PubMed

    Morgan, Cecilia C; Verzi, Diego H

    2011-08-01

    Among the ecomorphologically diverse Octodontoidea rodents, fossorial habits are prevalent in Ctenomyidae and Octodontidae and occur in some members of Echimyidae. To detect traits linked to scratch-digging, we analyzed morpho-structural variation in the carpus and metacarpus of 27 species of extinct and living octodontoids with epigean, fossorial and subterranean habits. Within a context of relative morphological uniformity, we detected the following specialized traits in the burrowing Clyomys (Echimyidae), Spalacopus (Octodontidae), Ctenomys and †Eucelophorus (Ctenomyidae): broad shortened carpus, robust metacarpals, markedly broad and short metacarpal V, and predominance of ray III (mesaxony, incipient in Spalacopus). In addition, the specialized subterranean Ctenomys presented an enlarged scapholunar in extensive contact with the unciform, and with a complex-shaped proximal articular surface. These features are interpreted as responses to mechanical requirements of scratch-digging, providing greater carpal rigidity and resistance to direct forces exerted during the digging stroke. In Ctenomys, the radius-scapholunar joint restricts movement at wrist level. The phylogenetic distribution of traits shows that the most derived carpal and metacarpal morphologies occur among subterranean octodontoids, also possessing important craniodental adaptations, and supports the hypothesis that the acquisition of digging specializations would have been linked to increasing burrowing frequency in some lineages. Nevertheless, octodontoids with less morphological specializations have metacarpal modifications advantageous for digging, suggesting that scratch-digging specialization preceded the acquisition of tooth-digging traits, in agreement with the general claim that scratch-digging is the primary digging strategy in burrowing mammals. PMID:21557745

  1. Multiple evolutionary origins of Australian soil-burrowing cockroaches driven by climate change in the Neogene.

    PubMed

    Lo, Nathan; Tong, K Jun; Rose, Harley A; Ho, Simon Y W; Beninati, Tiziana; Low, David L T; Matsumoto, Tadao; Maekawa, Kiyoto

    2016-02-24

    Parallel evolution is the independent appearance of similar derived phenotypes from similar ancestral forms. It is of key importance in the debate over whether evolution is stochastic and unpredictable, or subject to constraints that limit available phenotypic options. Nevertheless, its occurrence has rarely been demonstrated above the species level. Climate change on the Australian landmass over the last approximately 20 Myr has provided conditions conducive to parallel evolution, as taxa at the edges of shrinking mesic habitats adapted to drier biomes. Here, we investigate the phylogeny and evolution of Australian soil-burrowing and wood-feeding blaberid cockroaches. Soil burrowers (subfamily Geoscapheinae) are found in relatively dry sclerophyllous and scrubland habits, whereas wood feeders (subfamily Panesthiinae) are found in rainforest and wet sclerophyll. We sequenced and analysed mitochondrial and nuclear markers from 142 specimens, and estimated the evolutionary time scale of the two subfamilies. We found evidence for the parallel evolution of soil-burrowing taxa from wood-feeding ancestors on up to nine occasions. These transitions appear to have been driven by periods of aridification during the Miocene and Pliocene across eastern Australia. Our results provide an illuminating example of climate-driven parallel evolution among species. PMID:26888035

  2. Characteristics of roost sites used by burrowing owls (Athene cunicularia) wintering in Southern Texas

    USGS Publications Warehouse

    Williford, D.L.; Woodin, M.C.; Skoruppa, M.K.; Hickman, G.C.

    2007-01-01

    The western burrowing owl (Athene cunicularia hypugaea) is threatened in Mexico, endangered in Canada, and declining in most of the western United States. Most previous research has focused on burrowing owl breeding biology, and little is known about its winter ecology. We determined characteristics of roost sites used by western burrowing owls in southern Texas during winter. Data on 46 winter roost sites were collected from 15 November 2001 to 15 February 2002. Of these roost sites, 87% were located on agricultural land, 80% were along roads, and 74% were concrete, steel, or cast-iron culverts. Mean diameter (??SE) of roost site openings was 22 ?? 1.5 cm. Most roost sites (70%) were located on inaccessible private lands. Bare ground comprised 61% of ground cover within a 10-m radius of roost sites. We recommend that landowners and public-land managers should be encouraged to use smaller-diameter culverts when building roads or replacing old or damaged culverts and to graze livestock or mow around these culverts during winter.

  3. Distribution of the Chuckwalla, Western Burrowing Owl, and Six Bat Species on the Nevada Test Site

    SciTech Connect

    Cathy A. Willis

    1997-05-01

    Field Surveys were conducted in 1996 to determine the current distribution of several animal species of concern on the Nevada Test Site (NTS). They included the chuckwall (Sauromalus obesus), western burrowing owl (Speotyto cunicularia), and six species of bats. Nineteen chuckwallas and 118 scat locations were found during the chuckwalla field study. Eighteen western burrowing owls were found at 12 sighting locations during the 1996 field study. Of the eleven bat species of concern which might occur on the NTS, five, and possibly six, were captured during this survey. The U.S. Department of Energy, Nevada Operations Office, takes certain management actions to protect and conserve the chuckwalla, western burrowing owl, and bats on the NTS. These actions are described and include: (1) conducting surveys at sites of proposed land-disturbing activities (2) altering projects whenever possible to avoid or minimize impacts to these species (3) maintaining a geospatial database of known habitat for species of concern (4) sharing sighting and trap location data gathered on the NTS with other local land and resource managers, and (5) conducting periodic field surveys to monitor these species distribution and relative abundance on the NTS.

  4. Effects of invasive rats and burrowing seabirds on seeds and seedlings on New Zealand islands.

    PubMed

    Grant-Hoffman, Madeline N; Mulder, Christa P H; Bellingham, Peter J

    2010-04-01

    Rats (Rattus rattus, Rattus norvegicus, Rattus exulans) are important invaders on islands. They alter vegetation indirectly by preying on burrowing seabirds. These seabirds affect vegetation through nutrient inputs from sea to land and physical disturbance through trampling and burrowing. Rats also directly affect vegetation though consumption of seeds and seedlings. Seedling communities on northern New Zealand islands differ in composition and densities among islands which have never been invaded by rats, are currently invaded by rats, or from which rats have been eradicated. We conducted experimental investigations to determine the mechanisms driving these patterns. When the physical disturbance of seabirds was removed, in soils collected from islands and inside exclosures, seedling densities increased with seabird burrow density. For example, seedling densities inside exclosures were 10 times greater than those outside. Thus the negative effects of seabirds on seedlings, by trampling and uprooting, overwhelm the potentially beneficial effects of high levels of seed germination, seedling emergence, and possibly seed production, which result from seed burial and nutrient additions. Potential seedling density was reduced on an island where rats were present, germination of seeds from soils of this island was approximately half that found on other islands, but on this island seedling density inside exclosures was 7 times the density outside. Although the total negative effects of seabirds and rats on seedling densities are similar (reduced seedling density), the differences in mechanisms and life stages affected result in very different filters on the plant community. PMID:19921273

  5. Burrowing, byssus, and biomarkers: behavioral and physiological indicators of sublethal thermal stress in freshwater mussels (Unionidae)

    USGS Publications Warehouse

    Archambault, Jennifer M.; Cope, W. Gregory; Kwak, Thomas J.

    2013-01-01

    Recent research has elucidated the acute lethal effects of elevated water temperatures to glochidia (larvae), juvenile, and adult life stages of freshwater mussels (Order Unionida), but few studies have focused on sublethal effects of thermal stress. We evaluated the sublethal effects of elevated temperature on burrowing behavior and byssus production in juveniles, and on enzymatic biomarkers of stress in adults in acute (96 h) laboratory experiments in sediment, with two acclimation temperatures (22 and 27 °C) and two experimental water levels (watered and dewatered) as proxies for flow regime. Increasing temperature significantly reduced burrowing in all five species tested, and the dewatered treatment (a proxy for drought conditions) reduced burrowing in all but Amblema plicata. Production of byssal threads was affected most drastically by flow regime, with the probability of byssus presence reduced by 93–99% in the dewatered treatment, compared to the watered treatment (a proxy for low flow conditions); increasing temperature alone reduced byssus by 18–35%. Alanine aminotransferase and aspartate aminotransferase were significantly affected by treatment temperature in the 27 °C acclimation, watered test (p = 0.04 and 0.02, respectively). Our results are important in the context of climate change, because stream temperature and flow are expected to change with increasing air temperature and altered precipitation patterns.

  6. A theoretical study of burrowing in dry soil using razor clam-inspired kinematics

    NASA Astrophysics Data System (ADS)

    Winter, Amos; Isava, Monica

    2015-11-01

    This work investigates whether the digging kinematics of Ensis directus, the Atlantic razor clam, could be utilized in dry soil. In wet soil, E. directus uses contractions of its valves to relieve stress on the surrounding soil, and then draw water towards its body to create a pocket of fluidized substrate. This locally fluidized zone requires much less force to move through than static soil, resulting in burrowing energy that scales linearly with depth, rather than depth squared. In dry soil, if the valves of a clam-like device are contracted fast enough, the horizontal stress in the soil could be brought to a zero-stress state. This would correspondingly reduce the local vertical stresses to zero, which could drastically lower the forces required to burrow compared to moving through static dry soil. Using analytical models of soil failure mechanics, we investigated the critical timescales for inducing a zero-stress state in soil surrounding an E. directus-like device with contracting valves. This device was modeled as a similar size to a real razor clam (15 mm wide). It was found that for most dry soils, the device would have to contract its valves in 0.02 seconds, a speed within the realm of possibility for a mechanical system. These results suggest that the burrowing method used by E. directus could feasibly be adapted for digging in dry soil.

  7. Bioassessment of contaminant transport and distribution in aquatic ecosystems by chemical analysis of burrowing mayflies (Hexagenia)

    USGS Publications Warehouse

    Steingraeber, M.T.; Wiener, J.G.

    1995-01-01

    Burrowing mayfly nymphs (Ephemeroptera) inhabit and ingest fine-grained sediments and detritus that may be enriched with metals and persistent organic compounds. The burrowing nymphs can externally adsorb and internally assimilate these contaminants, providing a link for the food chain transfer of potentially toxic substances from sediments to organisms in higher trophic levels. The emergent adults are short-lived and do not feed, thus their gut contents do not contribute greatly to their total contaminant burden. These characteristics make Hexagenia spp. And certain other burrowing mayflies useful for assessing ecosystem contamination. General protocols are presented for the collection, processing and analysis of emergent mayflies to assess the spatial distribution and bioaccumulation of sediment-associated contaminants in aquatic ecosystems. Two essential components of this bioassessment approach are a network of on-site volunteers with the materials and instructions needed to correctly collect and store samples and quality assurance procedures to estimate the accuracy of chemical analyses. The utility of this approach is demonstrated with an example of its application to the Upper Mississippi River (USA). Determination of cadmium, mercury and polychlorinated biphenyl congeners in emergent Hexagenia bilineata from a 1250 km reach of this river revealed (1) several source areas of contaminants and (2) distinct patterns in the bioaccumulation (and apparent sediment-associated transport) of each residue on both small and large spatial scales.

  8. Occupancy rates of primary burrowing crayfish in natural and disturbed large river bottomlands

    USGS Publications Warehouse

    Loughman, Zachary J.; Welsh, Stuart; Simon, Thomas P.

    2012-01-01

    Among crayfish, primary burrowing species are the least understood ecologically. Many primary burrowing crayfish inhabit floodplains where forested landscapes have been fragmented by agricultural, industrial, or residential uses. In this study, site occupancy rates (ψ) were modeled for two primary burrowing crayfish, Fallicambarus fodiens (Cottle, 1863) and Cambarus thomai Jezerinac, 1993, from Ohio and Kanawha river floodplains in West Virginia, U.S.A. Fallicambarus fodiens is one of West Virginia’s rarest crayfish, while C. thomai is prevalent in most wetlands along both river floodplains. Occupancy rate modeling incorporated four environmental covariates (forest age, soil type, tree frequency, and land use). Based on presence/absence data, forests with tree ages >100 years (ΔQAICc = 0) and sites with loam soils (ΔQAICc = 1.80) were most likely to harbor F. fodiens populations. For C. thomai, several models were supported owing to model selection uncertainty, but those with the land use covariate had more total model weight (total w i = 0 . 54 ) than all other covariate models. Cambarus thomai rarely occupied industrial/agricultural sites, but were often present in forested and residential sites. Although the influence of covariates on site occupancy differed between species, both taxa readily utilized mature forested habitats when available. Conservation actions for F. fodiens and C. thomai should focus on preserving forested tracts along large river floodplains

  9. The Recruiter's Guidebook for Identification and Recruitment. Revised.

    ERIC Educational Resources Information Center

    Wisconsin State Dept. of Public Instruction, Madison. Div. for Management and Planning Services.

    A uniform understanding of the identification and recruitment component of the Wisconsin Elementary and Secondary Education Act Title I Migrant Education Program is the purpose of this recruiter's guidebook which can be an aid to recruiters, administrators, site coordinators, teachers, and parents in meeting the special educational needs of…

  10. The Students-Recruiting-Students Undergraduate Engineering Recruiting Programme.

    ERIC Educational Resources Information Center

    Gattis, Carol; Nachtmann, Heather; Youngblood, Alisha D.

    2003-01-01

    Describes the Students-Recruiting-Students (SRS) program developed to recruit high school students into the Industrial Engineering Department at the University of Arkansas. Presents four phases of the program along with seven years of program results. Encourages successful development of similar recruiting programs. (KHR)

  11. Recruiting and Selecting New Teachers: The Recruitment Budgeting Cycle.

    ERIC Educational Resources Information Center

    Beebe, Robert J.

    1998-01-01

    The recruitment budgeting cycle (RBC) places teacher-recruitment activities on a more systematic, professional plane. RBC action steps include reviewing and updating recruitment goals and activities, identifying the previous year's activities, defining outcome criteria for determining cost effectiveness, ranking activity costs, evaluating…

  12. Legal aspects of physician recruitment.

    PubMed

    Roediger, Joan M

    2005-01-01

    It's no secret that recruiting a new physician to your practice is a difficult task. Depending on your medical specialty, it may take two years and possibly longer to recruit the right person. This article addresses some of the key steps you can take now to overcome obstacles in the recruiting process. PMID:16095079

  13. eHealth recruitment challenges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about effective eHealth recruitment methods. This paper presents recruitment challenges associated with enrolling African-American girls aged 8-10 years in an eHealth obesity prevention program, their effect on the recruitment plan, and potential implications for eHealth research. Al...

  14. Recruitment of Hexagenia mayfly nymphs in western Lake Erie linked to environmental variability.

    PubMed

    Bridgeman, Thomas B; Schloesser, Don W; Krause, Ann E

    2006-04-01

    After a 40-year absence caused by pollution and eutrophication, burrowing mayflies (Hexagenia spp.) recolonized western Lake Erie in the mid 1990s as water quality improved. Mayflies are an important food resource for the economically valuable yellow perch fishery and are considered to be major indicator species of the ecological condition of the lake. Since their reappearance, however, mayfly populations have suffered occasional unexplained recruitment failures. In 2002, a failure of fall recruitment followed an unusually warm summer in which western Lake Erie became temporarily stratified, resulting in low dissolved oxygen levels near the lake floor. In the present study, we examined a possible link between Hexagenia recruitment and periods of intermittent stratification for the years 1997 2002. A simple model was developed using surface temperature, wind speed, and water column data from 2003 to predict stratification. The model was then used to detect episodes of stratification in past years for which water column data are unavailable. Low or undetectable mayfly recruitment occurred in 1997 and 2002, years in which there was frequent or extended stratification between June and September. Highest mayfly reproduction in 2000 corresponded to the fewest stratified periods. These results suggest that even relatively brief periods of stratification can result in loss of larval mayfly recruitment, probably through the effects of hypoxia. A trend toward increasing frequency of hot summers in the Great Lakes region could result in recurrent loss of mayfly larvae in western Lake Erie and other shallow areas in the Great Lakes. PMID:16711047

  15. Nichelle Nichols, NASA Recruiter

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Actress Nichelle Nichols was born in Robbins, Illinois on December 29, 1936. She played Lieutenant Uhura the Communications Officer on the U.S.S. Enterprise in the original series, Star Trek. Nichols stayed with the show and has appeared in six Star Trek movies. Her portrayal of Uhura on Star Trek marked one of the first non-stereotypical roles assigned to an African-American actress. She also provided the voice for Lt. Uhura on the Star Trek animated series in 1974-75. Before joining the crew on Star Trek, she sang and danced with Duke Ellington's band. Nichols was always interested in space travel. She flew aboard the C-141 Astronomy Observatory, which analyzed the atmospheres of Mars and Saturn on an eight hour, high altitude mission. From the late 1970's until the late 1980's, NASA employed Nichelle Nichols to recruit new astronaut candidates. Many of her new recruits were women or members of racial and ethnic minorities, including Guion Bluford (the first African-American astronaut), Sally Ride (the first female American astronaut), Judith Resnik (one of the original set of female astronauts, who perished during the launch of the Challenger on January 28, 1986), and Ronald McNair (the second African-American astronaut, and another victim of the Challenger accident). Currently Nichelle Nichols is actively involved in movies and special appearances. She is also a spokesperson for her favorite charity, 'The Kwanzaa Foundation.'

  16. Burrowing in the freshwater mussel Elliptio complanata is sexually dimorphic and feminized by low levels of atrazine

    PubMed Central

    Wedin, Maria Belopolsky; Bonventre, Josephine A.; Dillon-White, Marsha; Hines, Jessica; Weeks, Benjamin S.; André, Chantale; Schreibman, Martin P.; Gagné, Francois

    2015-01-01

    The widely used herbicide atrazine (ATR) may have endocrine-associated adverse effects, including on behavior. In this study, 120 adult freshwater mussels, Elliptio complanata, were exposed to ATR at the environmentally-relevant concentrations of 1.5, 15, or 150 μg/L. Burrowing depth was evaluated hourly for 6 hr and at sacrifice animals were sexed by gonad smear. Female controls burrowed overall approximately 30% less than males, the first report of sexual dimorphism in this behavior. Atrazine at 15 μg/L feminized burrowing in both sexes in that exposed animals burrowed 20% less than their same sex controls. Males treated with 1.5 μg /L ATR displayed approximately 20-fold higher vitellogenin (VTG) levels than same sex controls. Higher concentrations of ATR were not associated with increasing effects. A scatterplot showed a weak binomial curve associating low burrowing with high VTG levels. Taken together, these data suggest a non-linear dose-response in behavioral and physiological feminization produced by ATR and support the need to reconsider the widespread use of this compound. PMID:24279817

  17. Impacts of off-road vehicles (ORVs) on burrow architecture of ghost crabs (genus Ocypode) on sandy beaches.

    PubMed

    Lucrezi, Serena; Schlacher, Thomas A

    2010-06-01

    Recreational beach use with off-road vehicles is popular, but potentially harmful from an environmental perspective. Beaches are important habitats to invertebrates such as ghost crabs of the genus Ocyopde, which excavate extensive and elaborate burrows. Ghost crabs are sensitive to human pressures and changes in burrow architecture may thus be a consequence of disturbance by vehicles--the predictive hypothesis of this article. This was tested during the austral spring and summer by comparing 305 burrow casts between beaches open and closed to vehicles in Eastern Australia. Traffic influenced burrow architecture: there were smaller crabs on vehicle-impacted beaches, and after the peak traffic period (Christmas and New Year holidays), these crabs had tunnelled deeper into the sediment on shores rutted by cars. Crabs constructed all types of previously described burrows, but, significantly, smaller crabs from vehicle-impacted beaches simplified their shapes following heavy traffic disturbance from four (I, J, Y, M) to only two types (I, Y). These data support a model of active behavioural responses to disturbance from vehicles, extending the known effects of beach traffic to impacts on behavioural traits of the beach fauna. PMID:20411260

  18. Impacts of Off-Road Vehicles (ORVs) on Burrow Architecture of Ghost Crabs (Genus Ocypode) on Sandy Beaches

    NASA Astrophysics Data System (ADS)

    Lucrezi, Serena; Schlacher, Thomas A.

    2010-06-01

    Recreational beach use with off-road vehicles is popular, but potentially harmful from an environmental perspective. Beaches are important habitats to invertebrates such as ghost crabs of the genus Ocyopde, which excavate extensive and elaborate burrows. Ghost crabs are sensitive to human pressures and changes in burrow architecture may thus be a consequence of disturbance by vehicles—the predictive hypothesis of this article. This was tested during the austral spring and summer by comparing 305 burrow casts between beaches open and closed to vehicles in Eastern Australia. Traffic influenced burrow architecture: there were smaller crabs on vehicle-impacted beaches, and after the peak traffic period (Christmas and New Year holidays), these crabs had tunnelled deeper into the sediment on shores rutted by cars. Crabs constructed all types of previously described burrows, but, significantly, smaller crabs from vehicle-impacted beaches simplified their shapes following heavy traffic disturbance from four (I, J, Y, M) to only two types (I, Y). These data support a model of active behavioural responses to disturbance from vehicles, extending the known effects of beach traffic to impacts on behavioural traits of the beach fauna.

  19. eHealth recruitment challenges.

    PubMed

    Thompson, Debbe; Canada, Ashanti; Bhatt, Riddhi; Davis, Jennifer; Plesko, Lisa; Baranowski, Tom; Cullen, Karen; Zakeri, Issa

    2006-11-01

    Little is known about effective eHealth recruitment methods. This paper presents recruitment challenges associated with enrolling African-American girls aged 8-10 years in an eHealth obesity prevention program, their effect on the recruitment plan, and potential implications for eHealth research. Although the initial recruitment strategy was literature-informed, it failed to enroll the desired number of girls within a reasonable time period. Therefore, the recruitment strategy was reformulated to incorporate principles of social marketing and traditional marketing techniques. The resulting plan included both targeted, highly specific strategies (e.g., selected churches), and more broad-based approaches (e.g., media exposure, mass mailings, radio advertisements). The revised plan enabled recruitment goals to be attained. Media appeared to be particularly effective at reaching the intended audience. Future research should identify the most effective recruitment strategies for reaching potential eHealth audiences. PMID:17950873

  20. Effects of macroalgal mats and hypoxia on burrowing depth of the New Zealand cockle ( Austrovenus stutchburyi)

    NASA Astrophysics Data System (ADS)

    Marsden, Islay D.; Bressington, Melanie J.

    2009-02-01

    Macroalgal mats commonly occur in estuaries and sheltered embayments where they are thought to affect the oxygen conditions in the sediment, influence the geochemical process and influence the burrowing activity of bivalves. Laboratory experiments evaluated the effects of sediment hypoxia and algal mats on the burrowing ability and survival of the New Zealand cockle Austrovenus stutchburyi at 15 °C. Both dissolved oxygen concentration and time affected the burial depth of the cockles over the 12 days of the experiment. In hypoxic conditions (<2 mg L -1), cockles migrated to the sediment surface after 3.5 days and mortality occurred after 11 days. Bivalves exposed to oxygen concentrations of 2-3 mg L -1 buried closer to the sediment surface than those in the other treatments. Using a simulated tidal regime, in a mesocosm, burrowing behaviour of the cockle and pore-water oxygen conditions in the sediment were measured on exposure to experimental mats of Gracilaria chilensis and Ulva spp. for over 6 days. Algal mats on the surface of the sediment significantly lowered the dissolved oxygen concentration of the sediment pore-water and this effect was greater for the Ulva spp. treatment than the G. chilensis treatment. Cockles were buried more deeply in the control treatment without algae than in either of the two algal treatments. It is concluded that reduced oxygen conditions (<3.5 mg L -1) develop under macroalgal mats and that this reduces the burial depth of cockles. The potential harmful effects of the mats can depend on the species forming the mat and these effects are likely to be greater in the field than they are in controlled laboratory conditions.

  1. Importance of agricultural landscapes to nesting burrowing owls in the Northern Great Plains, USA

    USGS Publications Warehouse

    Restani, M.; Davies, J.M.; Newton, W.E.

    2008-01-01

    Anthropogenic habitat loss and fragmentation are the principle factors causing declines of grassland birds. Declines in burrowing owl (Athene cunicularia) populations have been extensive and have been linked to habitat loss, primarily the decline of black-tailed prairie dog (Cynomys ludovicianus) colonies. Development of habitat use models is a research priority and will aid conservation of owls inhabiting human-altered landscapes. From 2001 to 2004 we located 160 burrowing owl nests on prairie dog colonies on the Little Missouri National Grassland in North Dakota. We used multiple linear regression and Akaike's Information Criterion to estimate the relationship between cover type characteristics surrounding prairie dog colonies and (1) number of owl pairs per colony and (2) reproductive success. Models were developed for two spatial scales, within 600 m and 2,000 m radii of nests for cropland, crested wheatgrass (Agropyron cristatum), grassland, and prairie dog colonies. We also included number of patches as a metric of landscape fragmentation. Annually, fewer than 30% of prairie dog colonies were occupied by owls. None of the models at the 600 m scale explained variation in number of owl pairs or reproductive success. However, models at the 2,000 m scale did explain number of owl pairs and reproductive success. Models included cropland, crested wheatgrass, and prairie dog colonies. Grasslands were not included in any of the models and had low importance values, although percentage grassland surrounding colonies was high. Management that protects prairie dog colonies bordering cropland and crested wheatgrass should be implemented to maintain nesting habitat of burrowing owls. ?? 2008 Springer Science+Business Media B.V.

  2. Modelling field-data of preferential flow in paddy soil induced by earthworm burrows.

    PubMed

    Sander, Till; Gerke, Horst H

    2009-02-16

    Dye tracer studies revealed that earthworm burrows in the compacted plough pan of a Chinese paddy rice field can serve as preferential flow paths. It is, however, unclear whether the observed bypass of the compacted soil horizon might be explained by differences in hydraulic properties between the plough pan, the worm burrows with a surrounding denser drilosphere and the un-compacted subsoil, or by lower-permeable macropore walls. The objective is to separately analyse effects of the individual flow domains and to identify possible limiting factors (bottlenecks) in the flow system for better soil drainage management. Hydraulic properties are inversely estimated from in situ measurements of pressure heads and evaporation by using HYDRUS_1D code. Field data of 2D pressure head progression after dye tracer infiltration in the vicinity of worm burrows are simulated using HYDRUS_2D. The axisymmetric 2D flow model considers a highly permeable cylindrical macropore region in the centre of the flow domain, assuming Darcy's law is valid. The match between simulated and measured pressure head fields improved after including a lower-permeable drilosphere pore domain. Scenario simulations show that the inflow into the 'bypass-flow' domain are reduced by the homogenized topsoil (i.e., after puddling) and limited if the macropore domain is relatively shallow. The results suggest that basic structural features may in this concept be considered as one possibility to describe observed preferential flow patterns. The separate consideration of soil structural effects may help developing and improving management strategies for manipulation of preferential flow in soils of paddy fields. PMID:19064301

  3. Infestation of the clam Chione fluctifraga by the burrowing worm Polydora sp. nov. in laboratory conditions.

    PubMed

    Tinoco-Orta, Gissel Dalila; Cáceres-Martínez, Jorge

    2003-07-01

    Burrowing worms that belong to Polydora spp. infest marine mollusks cultured worldwide, causing problems for production and marketing. The clam Chione fluctifraga is semi-cultured in Bahía Falsa, Baja California, NW Mexico, and some clams harbor burrowing worms. The present study was carried out to determine the identity of the worm species infesting the clam, the infesting process by cohabitation of infested and non-infested clams in aquaria with a variety of substrates (fine sand, gross sand, plastic bag used for clam culture, and aquarium without substrate) and turbulence conditions, and the occurrence of architomy phenomena in connection with infestation of the clam. The burrowing worm was considered as a nova species due to its singular limbate neurosetae and notosetae in the setiger 5, hooks in the setiger 6, eyes not present, and general pigmentation, among other characteristics. Infestation was similar in all substrates and turbulence conditions, but it was more abundant on clams previously infested than on those free of worms, showing a preferential settlement of worm infesting stages on pre-infested clams. Regeneration was observed in all segments of the worm: anterior (metastomium), medium, and posterior (prostomium); the complete regeneration time occurred in 40 days. This is the first record of architomy in a species of Polydora and this phenomenon could account for the increase of infestation intensity in pre-infested clams at the end of the study period. Infestation of clams by settling polichaete in the conditions studied, and the architomy process in this worm species, shows its great infesting capacity. PMID:12877826

  4. A 200 year chronology of burrowing mayflies (Hexagenia spp.) in Saginaw Bay

    USGS Publications Warehouse

    Schloesser, Donald W.; Robbins, John A.; Matisoff, Gerald; Nalepa, Thomas F.; Morehead, Nancy R.

    2014-01-01

    After an absence of 50 years, burrowing mayflies (Hexagenia spp.) colonized western Lake Erie which led to interest in whether this fauna can be used to measure recovery in nearshore waters throughout the Great Lakes. However, in many areas we do not know if mayflies were native/endemic and thus, whether recovery is a logical measure to assess progress of recovery. In the present study, we construct a chronologic record of relative abundance of burrowing mayflies in Saginaw Bay by the use of mayfly tusks and radionuclides in sediments (i.e., a paleoecologic record) and historic records of mayfly nymphs in the bay. These records reveal that mayflies: (1) were few before 1799, which indicates that nymphs were probably native/endemic in the bay, (2) increased between 1799 and 1807 and remained at relatively high levels between 1807 and 1965, probably in response to increased nutrient run-off from the watershed, (3) declined dramatically between 1965 and 1973, probably as a result of excessive eutrophication in the mid-1950s; and, (4) were few and highly variable between 1973 and 2001, probably as a result of low and unstable abundances of mayfly nymphs. Historic records verify that nymphs disappeared in the bay in the late-1950s to early-1960s which is in agreement with the paleoecologic record. Reoccurrence of low abundances of nymphs in the bay between 1991 and 2008 and comparison of chronologic records of nymphs in Saginaw Bay and western Lake Erie suggest that mayflies may return to Saginaw Bay in the early-21st century. Undoubtedly, watershed conservation and three decades of pollution abatement have set the stage for a recovery of burrowing mayflies in Saginaw Bay, and possibly in other areas of the Great Lakes.

  5. Comparing food limitation among three stages of nesting: supplementation experiments with the burrowing owl

    PubMed Central

    Wellicome, Troy I; Danielle Todd, L; Poulin, Ray G; Holroyd, Geoffrey L; Fisher, Ryan J

    2013-01-01

    Abstract Food availability is an important limiting factor for avian reproduction. In altricial birds, food limitation is assumed to be more severe during the nestling stage than during laying or incubation, but this has yet to be adequately tested. Using food-supplementation experiments over a 5-year period, we determined the degree and timing of food limitation for burrowing owls (Athene cunicularia) breeding in Canada. Burrowing owls are an endangered species and food limitation during the nestling stage could influence reproductive performance of this species at the northern extent of their range. Supplemented pairs fledged on average 47% more owlets than unfed pairs, except during a year when natural food was not limiting (i.e., a prey irruption year). The difference in fledgling production resulted from high nestling mortality in unfed broods, with 96% of all nestling deaths being attributed to food shortage. Supplemental feeding during the nestling period also increased fledgling structural size. Pairs fed from the start of laying produced the same number of hatchlings as pairs that received no supplemental food before hatch. Furthermore, pairs supplemented from egg laying to fledging and pairs supplemented during the nestling period alone had the same patterns of nestling survival, equal numbers of fledglings, and similar fledgling mass and structural size. Our results provide empirical support for the hypothesis that the nestling period is the most food-limited phase of the breeding cycle. The experimental design we introduce here could be used with other altricial species to examine how the timing of food limitation differs among birds with a variety of life-history strategies. For burrowing owls, and other species with similar life histories, long-term, large-scale, and appropriately timed habitat management increasing prey abundance or availability is critical for conservation. Our results provide empirical support for the hypothesis that the nestling

  6. Surgical removal of a thymoma in a burrowing owl (Athene cunicularia).

    PubMed

    Kinney, Matthew E; Hanley, Christopher S; Trupkiewicz, John G

    2012-06-01

    A 12-year-old male burrowing owl (Athene cunicularia) was presented for evaluation of a mass in the right cervical region. A thymoma was diagnosed after surgical resection and histopathologic evaluation. Extensive adherence of the thymoma to the esophagus and suspected invasion into the right jugular vein contributed to a poor postsurgical outcome. Diagnosis and treatment of thymomas in avian species is similar to that in mammals. Surgical removal of noninvasive thymomas is usually curative. Thymomas are rarely reported in avian species and this is the first report in a strigiform bird. PMID:22872980

  7. Comparing food limitation among three stages of nesting: supplementation experiments with the burrowing owl.

    PubMed

    Wellicome, Troy I; Danielle Todd, L; Poulin, Ray G; Holroyd, Geoffrey L; Fisher, Ryan J

    2013-08-01

    Food availability is an important limiting factor for avian reproduction. In altricial birds, food limitation is assumed to be more severe during the nestling stage than during laying or incubation, but this has yet to be adequately tested. Using food-supplementation experiments over a 5-year period, we determined the degree and timing of food limitation for burrowing owls (Athene cunicularia) breeding in Canada. Burrowing owls are an endangered species and food limitation during the nestling stage could influence reproductive performance of this species at the northern extent of their range. Supplemented pairs fledged on average 47% more owlets than unfed pairs, except during a year when natural food was not limiting (i.e., a prey irruption year). The difference in fledgling production resulted from high nestling mortality in unfed broods, with 96% of all nestling deaths being attributed to food shortage. Supplemental feeding during the nestling period also increased fledgling structural size. Pairs fed from the start of laying produced the same number of hatchlings as pairs that received no supplemental food before hatch. Furthermore, pairs supplemented from egg laying to fledging and pairs supplemented during the nestling period alone had the same patterns of nestling survival, equal numbers of fledglings, and similar fledgling mass and structural size. Our results provide empirical support for the hypothesis that the nestling period is the most food-limited phase of the breeding cycle. The experimental design we introduce here could be used with other altricial species to examine how the timing of food limitation differs among birds with a variety of life-history strategies. For burrowing owls, and other species with similar life histories, long-term, large-scale, and appropriately timed habitat management increasing prey abundance or availability is critical for conservation. Our results provide empirical support for the hypothesis that the nestling period is

  8. Issues to Be Considered in Counting Burrows as a Measure of Atlantic Ghost Crab Populations, an Important Bioindicator of Sandy Beaches

    PubMed Central

    Pombo, Maíra; Turra, Alexander

    2013-01-01

    The use of indirect estimates of ghost-crab populations to assess beach disturbance has several advantages, including non-destructiveness, ease and low cost, although this strategy may add some degree of noise to estimates of population parameters. Resolution of these shortcomings may allow wider use of these populations as an indicator of differences in quality among beaches. This study analyzed to what extent the number of crab burrows may diverge from the number of animals, considering beach morphology, burrow depth and signs of occupation as contributing factors or indicators of a higher or lower occupation rate. We estimated the occupation rate of crabs in burrows on nine low-use beaches, which were previously categorized as dissipative, intermediate or reflexive. Three random 2-m-wide transects were laid perpendicular to the shoreline, where burrows were counted and excavated to search for crabs. The depth and signs of recent activity around the burrows were also recorded. The occupation rate differed on the different beaches, but morphodynamics was not identified as a grouping factor. A considerable number of burrows that lacked signs of recent activity proved to be occupied, and the proportions of these burrows also differed among beaches. Virtually all burrows less than 10 cm deep were unoccupied; the occupation rate tended to increase gradually to a burrow depth of 20–35 cm. Other methods (water, smoke, and traps) were applied to measure the effectiveness of excavating as a method for burrow counts. Traps and excavation proved to be the best methods. These observations illustrate the possible degree of unreliability of comparisons of beaches based on indirect measures. Combining burrow depth assessment with surrounding signs of occupation proved to be a useful tool to minimize biases. PMID:24376748

  9. Issues to be considered in counting burrows as a measure of Atlantic ghost crab populations, an important bioindicator of sandy beaches.

    PubMed

    Pombo, Maíra; Turra, Alexander

    2013-01-01

    The use of indirect estimates of ghost-crab populations to assess beach disturbance has several advantages, including non-destructiveness, ease and low cost, although this strategy may add some degree of noise to estimates of population parameters. Resolution of these shortcomings may allow wider use of these populations as an indicator of differences in quality among beaches. This study analyzed to what extent the number of crab burrows may diverge from the number of animals, considering beach morphology, burrow depth and signs of occupation as contributing factors or indicators of a higher or lower occupation rate. We estimated the occupation rate of crabs in burrows on nine low-use beaches, which were previously categorized as dissipative, intermediate or reflexive. Three random 2-m-wide transects were laid perpendicular to the shoreline, where burrows were counted and excavated to search for crabs. The depth and signs of recent activity around the burrows were also recorded. The occupation rate differed on the different beaches, but morphodynamics was not identified as a grouping factor. A considerable number of burrows that lacked signs of recent activity proved to be occupied, and the proportions of these burrows also differed among beaches. Virtually all burrows less than 10 cm deep were unoccupied; the occupation rate tended to increase gradually to a burrow depth of 20-35 cm. Other methods (water, smoke, and traps) were applied to measure the effectiveness of excavating as a method for burrow counts. Traps and excavation proved to be the best methods. These observations illustrate the possible degree of unreliability of comparisons of beaches based on indirect measures. Combining burrow depth assessment with surrounding signs of occupation proved to be a useful tool to minimize biases. PMID:24376748

  10. Influence of a burrowing, metal-tolerant polychaete on benthic metabolism, denitrification and nitrogen regeneration in contaminated estuarine sediments.

    PubMed

    Banks, Joanne L; Ross, D Jeff; Keough, Michael J; Macleod, Catriona K; Keane, John; Eyre, Bradley D

    2013-03-15

    We investigated the effects of the burrowing cirratulid polychaete Cirriformia filigera (Delle Chiaje, 1828) on benthic respiration and nitrogen regeneration in metal-contaminated estuarine sediments using laboratory mesocosms. C. filigera is a dominant component of assemblages in the most severely contaminated sediments within the Derwent estuary, southern Australia. In the presence of C. filigera sediment O2 consumption doubled, with approximately 55% of this increase due to their respiration and the remaining 45% attributable to oxidation reactions and increased microbial respiration associated with burrow walls. Combined NO3 and NO2 fluxes were unaffected. The addition of labile organic matter did not affect benthic fluxes, in the presence or absence of C. filigera, presumably due to the short timeframe of the experiment and naturally enriched test sediments. The results suggest that a combination of tolerance and burrowing activity enables this species to provide an ecosystem service in the removal of N from contaminated sites. PMID:23398743

  11. Estimating animal populations and body sizes from burrows: Marine ecologists have their heads buried in the sand

    NASA Astrophysics Data System (ADS)

    Schlacher, Thomas A.; Lucrezi, Serena; Peterson, Charles H.; Connolly, Rod M.; Olds, Andrew D.; Althaus, Franziska; Hyndes, Glenn A.; Maslo, Brooke; Gilby, Ben L.; Leon, Javier X.; Weston, Michael A.; Lastra, Mariano; Williams, Alan; Schoeman, David S.

    2016-06-01

    Most ecological studies require knowledge of animal abundance, but it can be challenging and destructive of habitat to obtain accurate density estimates for cryptic species, such as crustaceans that tunnel deeply into the seafloor, beaches, or mudflats. Such fossorial species are, however, widely used in environmental impact assessments, requiring sampling techniques that are reliable, efficient, and environmentally benign for these species and environments. Counting and measuring the entrances of burrows made by cryptic species is commonly employed to index population and body sizes of individuals. The fundamental premise is that burrow metrics consistently predict density and size. Here we review the evidence for this premise. We also review criteria for selecting among sampling methods: burrow counts, visual censuses, and physical collections. A simple 1:1 correspondence between the number of holes and population size cannot be assumed. Occupancy rates, indexed by the slope of regression models, vary widely between species and among sites for the same species. Thus, 'average' or 'typical' occupancy rates should not be extrapolated from site- or species specific field validations and then be used as conversion factors in other situations. Predictions of organism density made from burrow counts often have large uncertainty, being double to half of the predicted mean value. Whether such prediction uncertainty is 'acceptable' depends on investigators' judgements regarding the desired detectable effect sizes. Regression models predicting body size from burrow entrance dimensions are more precise, but parameter estimates of most models are specific to species and subject to site-to-site variation within species. These results emphasise the need to undertake thorough field validations of indirect census techniques that include tests of how sensitive predictive models are to changes in habitat conditions or human impacts. In addition, new technologies (e.g. drones

  12. Flea fitness is reduced by high fractional concentrations of CO₂ that simulate levels found in their hosts' burrows.

    PubMed

    Downs, Cynthia J; Pinshow, Berry; Khokhlova, Irina S; Krasnov, Boris R

    2015-11-01

    Nidicolous ectoparasites such as fleas and gamasid mites that feed on small and medium-sized mammals spend much of their time in their hosts' burrows, which provide an environment for living, and often feeding, to their pre-imaginal and/or adult stages. Thus, these ectoparasites should be adapted to environmental conditions in burrows, including high fractional concentrations of CO2 (F(CO2)). We examined how a high F(CO2) (0.04) affected survival and reproductive success of a hematophagous ectoparasite of burrowing rodents using fleas Xenopsylla ramesis and Sundevall's jirds Meriones crassus. In the first experiment, fleas fed on hosts housed in high-CO2 (F(CO2) =0.04) or atmospheric-CO2 (F(CO2) ≈0.0004) air, and were allowed to breed. In a second experiment, fleas were maintained in high CO2 or CO2-free air with no hosts to determine how CO2 levels affect survival and activity levels. We found that at high F(CO2) fleas laid fewer eggs, reducing reproductive success. In addition, at high F(CO2), activity levels and survival of fleas were reduced. Our results indicate that fleas do not perform well in the F(CO2) used in this experiment. Previous research indicated that the type and intensity of the effects of CO2 concentration on the fitness of an insect depend on the F(CO2) used, so we advise caution when generalizing inferences drawn to insects exposed to other F(CO2). If, however, F(CO2) found in natural mammal burrows brings about reduced fitness in fleas in general, then burrowing hosts may benefit from reduced parasite infestation if burrow air F(CO2) is high. PMID:26582933

  13. Traces and burrowing behaviors of the Cicada nymph Cicadetta calliope: Neoichnology and paleoecological significance of extant soil-dwelling insects

    USGS Publications Warehouse

    Smith, J.J.; Hasiotis, S.T.

    2008-01-01

    This study documents the traces and burrowing behaviors of nymphs of the prairie cicada Cicadetta calliope (Hemiptera: Cicadidae), as observed in neoichnological experiments. Cicada nymphs were collected from the C horizons of sandy Fluvents along the Kansas River east of Lawrence, Kansas. The nymphs appeared to be fifth instars, 13-17 mm long and 6-7 mm wide. Nymphs were placed in plastic enclosures containing layers of colored, moist, very fine-grained sand. They burrowed immediately, excavating air-filled, sediment-enclosed cells between 20 mm and 40 mm long and averaging 9 mm wide. Burrowing was completed in three stages: (1) sediment in the forward portion of the cell was excavated and rolled into a ball with the forelimbs; (2) the nymph turned 180?? using a forward roll, and moved to the back of the cell; and (3) the sediment ball was pushed up against the back wall of the cell and kneaded with the forelimbs into a thin layer. Resulting burrow traces are sinuous and distinctly meniscate and demonstrate that insect larvae construct meniscate, backfilled burrows in well-drained terrestrial settings. Cicadetta calliope nymphs and their traces are excellent analogs for meniscate trace fossils commonly found in late Paleozoic-Cenozoic alluvial deposits and paleosols. Such meniscate trace fossils are useful for interpreting the paleoenvironment and paleohydrogeology of the units in which they are found. In addition, such backfilled burrows can be used to supplement the fossil record of cicada-like hemipterans, currently known only from the latest Permian to the Early Triassic. Copyright ?? 2008, SEPM (Society for Sedimentary Geology).

  14. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon

    EPA Science Inventory

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  15. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon - April 2009

    EPA Science Inventory

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  16. Artificial Warthog Burrows Used to Sample Adult and Immature Tsetse (Glossina spp) in the Zambezi Valley of Zimbabwe

    PubMed Central

    Hargrove, John W.; Muzari, M. Odwell

    2015-01-01

    Background The biology of adult tsetse (Glossina spp), vectors of trypanosomiasis in Africa, has been extensively studied – but little is known about larviposition in the field. Methodology/Principal Findings In September-November 1998, in the hot-dry season in Zimbabwe’s Zambezi Valley, we used artificial warthog burrows to capture adult females as they deposited larvae. Females were subjected to ovarian dissection and were defined as perinatal flies, assumed to have entered burrows to larviposit, if oocyte sizes indicated >95% pregnancy completion. Perinatal flies were defined as full-term pregnant if there was a late third instar larva in utero, or postpartum if the uterus was empty. All other females were defined as pre-full-term pregnant (pre-FT). Of 845 G. m. morsitans captured, 91% (765) were female and 295/724 (41%) of females dissected were perinatal flies. By contrast, of 2805 G. pallidipes captured only 71% (2003) were female and only 33% (596/1825) of females were perinatal. Among all perinatal females 67% (596/891) were G. pallidipes. Conversely, in burrows not fitted with traps – such that flies were free to come and go – 1834 (59%) of pupae deposited were G. m. morsitans and only 1297 (41%) were G. pallidipes. Thus, while more full-term pregnant G. pallidipes enter burrows, greater proportions of G. m. morsitans larviposit in them, reflecting a greater discrimination among G. pallidipes in choosing larviposition sites. Catches of males and pre-FT females increased strongly with temperatures above 32°C, indicating that these flies used burrows as refuges from high ambient temperatures. Conversely, catches of perinatal females changed little with maximum temperature but declined from late September through November: females may anticipate that burrows will be inundated during the forthcoming wet season. Ovarian age distributions of perinatal and pre-FT females were similar, consistent with all ages of females larvipositing in burrows with

  17. Genetic adaptations of the plateau zokor in high-elevation burrows

    PubMed Central

    Shao, Yong; Li, Jin-Xiu; Ge, Ri-Li; Zhong, Li; Irwin, David M.; Murphy, Robert W.; Zhang, Ya-Ping

    2015-01-01

    The plateau zokor (Myospalax baileyi) spends its entire life underground in sealed burrows. Confronting limited oxygen and high carbon dioxide concentrations, and complete darkness, they epitomize a successful physiological adaptation. Here, we employ transcriptome sequencing to explore the genetic underpinnings of their adaptations to this unique habitat. Compared to Rattus norvegicus, genes belonging to GO categories related to energy metabolism (e.g. mitochondrion and fatty acid beta-oxidation) underwent accelerated evolution in the plateau zokor. Furthermore, the numbers of positively selected genes were significantly enriched in the gene categories involved in ATPase activity, blood vessel development and respiratory gaseous exchange, functional categories that are relevant to adaptation to high altitudes. Among the 787 genes with evidence of parallel evolution, and thus identified as candidate genes, several GO categories (e.g. response to hypoxia, oxygen homeostasis and erythrocyte homeostasis) are significantly enriched, are two genes, EPAS1 and AJUBA, involved in the response to hypoxia, where the parallel evolved sites are at positions that are highly conserved in sequence alignments from multiple species. Thus, accelerated evolution of GO categories, positive selection and parallel evolution at the molecular level provide evidences to parse the genetic adaptations of the plateau zokor for living in high-elevation burrows. PMID:26602147

  18. Interactive effects of prey and p,p'-DDE on burrowing owl population dynamics.

    PubMed

    Gervais, Jennifer A; Hunter, Christine M; Anthony, Robert G

    2006-04-01

    We used population models to explore the effects of the organochlorine contaminant p,p'-DDE and fluctuations in vole availability on the population dynamics of Burrowing Owls (Athene cunicularia). Previous work indicated an interaction between low biomass of voles in the diet and moderate levels of p,p'-DDE in Burrowing Owl eggs that led to reproductive impairment. We constructed periodic and stochastic matrix models that incorporated three vole population states observed in the field: average, peak, and crash years. We modeled varying frequencies of vole crash years and a range of impairment of owl demographic rates in vole crash years. Vole availability had a greater impact on owl population growth rate than did reproductive impairment if vole populations peaked and crashed frequently. However, this difference disappeared as the frequency of vole crash years declined to once per decade. Fecundity, the demographic rate most affected by p,p'-DDE, had less impact on population growth rate than adult or juvenile survival. A life table response experiment of time-invariant matrices for average, peak, and crash vole conditions showed that low population growth under vole crash conditions was due to low adult and juvenile survival rates, whereas the extremely high population growth under vole peak conditions was due to increased fecundity. Our results suggest that even simple models can provide useful insights into complex ecological interactions. This is particularly valuable when temporal or spatial scales preclude manipulative experimental work in the field or laboratory. PMID:16711053

  19. The antenna of a burrowing dragonfly larva, Onychogomphus forcipatus (Anisoptera, Gomphidae).

    PubMed

    Rebora, Manuela; Piersanti, Silvana; Salerno, Gianandrea; Gorb, Stanislav

    2015-11-01

    The larva of the dragonfly Onychogomphus forcipatus (Anisoptera, Gomphidae) has a burrowing lifestyle and antennae composed of four short and broad segments (scape, pedicel and a two-segmented flagellum). The present ultrastructural investigation revealed that different sensilla and one gland are located on the antenna. There is a great diversity of mechanoreceptors of different kinds. In particular club-shaped sensilla, sensilla chaetica, and tree-like sensilla show the typical structure of bristles, the most common type of mechanoreceptors, usually responding to direct touch, while numerous long thin thorny trichoid sensilla show a morphology recalling the structure of filiform hair mechanoreceptors. The latter ones are presumably important in larval Odonata for current detection and rheotactic orientation, especially in a burrowing species. On the smooth apical cuticle of the second flagellar segment, three structures are visible: (1) a small ellipsoidal pit hosting a convoluted peg, the morphology of which resembles that of a typical chemoreceptor (even if pores are lacking), (2) a couple of small pits (not investigated under TEM), and (3) one wide depression with spherical structures, the internal morphology of which lets us assume that it is a gland with unknown function. This is the first report of an antennal gland in palaeopteran insects. PMID:26113430

  20. Real estate ads in Emei music frog vocalizations: female preference for calls emanating from burrows.

    PubMed

    Cui, Jianguo; Tang, Yezhong; Narins, Peter M

    2012-06-23

    During female mate choice, both the male's phenotype and resources (e.g. his nest) contribute to the chooser's fitness. Animals other than humans are not known to advertise resource characteristics to potential mates through vocal communication; although in some species of anurans and birds, females do evaluate male qualities through vocal communication. Here, we demonstrate that calls of the male Emei music frog (Babina dauchina), vocalizing from male-built nests, reflect nest structure information that can be recognized by females. Inside-nest calls consisted of notes with energy concentrated at lower frequency ranges and longer note durations when compared with outside-nest calls. Centre frequencies and note durations of the inside calls positively correlate with the area of the burrow entrance and the depth of the burrow, respectively. When given a choice between outside and inside calls played back alternately, more than 70 per cent of the females (33/47) chose inside calls. These results demonstrate that males of this species faithfully advertise whether or not they possess a nest to potential mates by vocal communication, which probably facilitates optimal mate selection by females. These results revealed a novel function of advertisement calls, which is consistent with the wide variation in both call complexity and social behaviour within amphibians. PMID:22158736

  1. Genetic adaptations of the plateau zokor in high-elevation burrows.

    PubMed

    Shao, Yong; Li, Jin-Xiu; Ge, Ri-Li; Zhong, Li; Irwin, David M; Murphy, Robert W; Zhang, Ya-Ping

    2015-01-01

    The plateau zokor (Myospalax baileyi) spends its entire life underground in sealed burrows. Confronting limited oxygen and high carbon dioxide concentrations, and complete darkness, they epitomize a successful physiological adaptation. Here, we employ transcriptome sequencing to explore the genetic underpinnings of their adaptations to this unique habitat. Compared to Rattus norvegicus, genes belonging to GO categories related to energy metabolism (e.g. mitochondrion and fatty acid beta-oxidation) underwent accelerated evolution in the plateau zokor. Furthermore, the numbers of positively selected genes were significantly enriched in the gene categories involved in ATPase activity, blood vessel development and respiratory gaseous exchange, functional categories that are relevant to adaptation to high altitudes. Among the 787 genes with evidence of parallel evolution, and thus identified as candidate genes, several GO categories (e.g. response to hypoxia, oxygen homeostasis and erythrocyte homeostasis) are significantly enriched, are two genes, EPAS1 and AJUBA, involved in the response to hypoxia, where the parallel evolved sites are at positions that are highly conserved in sequence alignments from multiple species. Thus, accelerated evolution of GO categories, positive selection and parallel evolution at the molecular level provide evidences to parse the genetic adaptations of the plateau zokor for living in high-elevation burrows. PMID:26602147

  2. The Brain on Stress: Insight from Studies Using the Visible Burrow System

    PubMed Central

    McEwen, Bruce S.; McKittrick, Christina R.; Tamashiro, Kellie L. K.; Sakai, Randall R.

    2016-01-01

    The discovery of adrenal steroid receptors outside of the hypothalamus in the hippocampus and other forebrain regions catalyzed research on the effects of stress upon cognitive function, emotions and self-regulatory behaviors as well as the molecular, cellular and neuroanatomical mechanisms underlying acute and chronic stress effects on the brain. Indeed, this work has shown that the brain is a plastic and vulnerable organ in the face of acute and chronic stress. The insight that Bob and Caroline Blanchard had in developing and interpreting findings using the Visible Burrow System model made an enormous contribution to the current view that the human brain is very sensitive to the social environment and to agonistic interactions between individuals. Their collaboration with Sakai and McEwen at The Rockefeller University extended application of the Visible Burrow System model to demonstrate that it also was a unique and highly relevant neuroethological model with which to study stress and adaptation to stressors. Those studies focused on the brain and systemic organ responses to stress and, in turn, described that the brain is also very responsive to changes in systemic physiology. PMID:26066722

  3. Chronic fluoxetine exposure alters movement and burrowing in adult freshwater mussels.

    PubMed

    Hazelton, Peter D; Du, Bowen; Haddad, Samuel P; Fritts, Andrea K; Chambliss, C Kevin; Brooks, Bryan W; Bringolf, Robert B

    2014-06-01

    The antidepressant fluoxetine is commonly found in aquatic fauna living near or downstream from point-sources of municipal waste effluent. Continuous release of fluoxetine results in increased effective exposure duration in surface waters, resulting in a chronic exposure for animals downstream, particularly in effluent dominated ecosystems. Fluoxetine is known to cause disruptions in reproductive behavior of freshwater mussels (order Unionoida), including stimulating release of gametes, parturition of glochidia (larvae), and changes in lure display and foot protrusion. However, the ecological relevance of these effects at environmental concentrations is unknown. We conducted a 67-d exposure of adult Lampsilis fasciola to fluoxetine concentrations of 0, 0.5, 2.5, and 22.3μg/L and assessed impacts on behavior (lateral movement, burrowing, and filtering) and metabolism (glycogen storage and respiration). Mussels treated with 2.5 and 22.3μg/L fluoxetine displayed mantle lures significantly (p<0.05) more than controls. Animals treated with 22.3μg/L fluoxetine were statistically more likely to have shorter time-to-movement, greater total movement, and initiate burrowing sooner than control animals. These observations suggest that increased activity of mussels exposed to fluoxetine may result in increased susceptibility to predators and may lead to a reduction in energy stores. PMID:24438840

  4. Real estate ads in Emei music frog vocalizations: female preference for calls emanating from burrows

    PubMed Central

    Cui, Jianguo; Tang, Yezhong; Narins, Peter M.

    2012-01-01

    During female mate choice, both the male's phenotype and resources (e.g. his nest) contribute to the chooser's fitness. Animals other than humans are not known to advertise resource characteristics to potential mates through vocal communication; although in some species of anurans and birds, females do evaluate male qualities through vocal communication. Here, we demonstrate that calls of the male Emei music frog (Babina dauchina), vocalizing from male-built nests, reflect nest structure information that can be recognized by females. Inside-nest calls consisted of notes with energy concentrated at lower frequency ranges and longer note durations when compared with outside-nest calls. Centre frequencies and note durations of the inside calls positively correlate with the area of the burrow entrance and the depth of the burrow, respectively. When given a choice between outside and inside calls played back alternately, more than 70 per cent of the females (33/47) chose inside calls. These results demonstrate that males of this species faithfully advertise whether or not they possess a nest to potential mates by vocal communication, which probably facilitates optimal mate selection by females. These results revealed a novel function of advertisement calls, which is consistent with the wide variation in both call complexity and social behaviour within amphibians. PMID:22158736

  5. Geomys bursars burrowing patterns: influence of season and food patch structure

    USGS Publications Warehouse

    Andersen, Douglas C.

    1987-01-01

    The relationship between belowground food resources and the pattern and pace of soil excavation by Geomys bursarius, the plains pocket gopher, was assessed during spring and autumn using replicated 18 x 18 m enclosures containing uniform arrays of food plants (Daucus carota) at spacings assumed to result in burrowing being energetically profitable (25 and 50 cm) or unprofitable (100 cm and empty). Soil excavation rate, measured in terms of either daily additions to tunnel length or volume, or the maximum volume excavated during a 3-d interval, varied greatly among individuals. No significant effect due to season or density of belowground plant biomass was detected when burrowing was profitable. Individuals readily initiated aboveground travel in unprofitable treatments. Soil bulk density was negatively related and animal body mass positively related to excavation rate. Individuals deposited from 41 to 87% of excavated soil on the ground surface; the remainder was used to backfill previously created tunnels or chambers. Plant size, but not plant spacing, affected the ratio of the volumes deposited aboveground and belowground. There was no evidence that animals in enclosures disturbed soil in a manner quantitatively or qualitatively different from free-ranging adults. The large proportions and absolute quantities (up to 30 L/d) of soil involved suggest that backfilling may affect ecosystem structure and functioning as much as surface mound-building.

  6. Burrowing hard corals occurring on the sea floor since 80 million years ago

    PubMed Central

    Sentoku, Asuka; Tokuda, Yuki; Ezaki, Yoichi

    2016-01-01

    We describe a previously unknown niche for hard corals in the small, bowl-shaped, solitary scleractinian, Deltocyathoides orientalis (Family Turbinoliidae), on soft-bottom substrates. Observational experiments were used to clarify how the sea floor niche is exploited by turbinoliids. Deltocyathoides orientalis is adapted to an infaunal mode of life and exhibits behaviours associated with automobility that include burrowing into sediments, vertical movement through sediments to escape burial, and recovery of an upright position after being overturned. These behaviours were achieved through repeated expansion and contraction of their peripheral soft tissues, which constitute a unique muscle-membrane system. Histological analysis showed that these muscle arrangements were associated with deeply incised inter-costal spaces characteristic of turbinoliid corals. The oldest known turbinoliid, Bothrophoria ornata, which occurred in the Cretaceous (Campanian), also possessed a small, conical skeleton with highly developed costae. An infaunal mode of life became available to turbinoliids due to the acquisition of automobility through the muscle-membrane system at least 80 million years ago. The newly discovered active burrowing strategies described herein provide new insights into the use of an unattached mode of life by corals inhabiting soft-bottom substrates throughout the Phanerozoic. PMID:27074813

  7. Field evaluation of carbon dioxide baits for sampling Ornithodoros turicata (Acari: Argasidae) in gopher tortoise burrows.

    PubMed

    Adeyeye, O A; Butler, J F

    1991-01-01

    Field studies were conducted to assess the reliability of carbon dioxide baits in sampling Ornithodoros turicata Duges. Tick response to about 50 g of dry ice placed at various distances away from tick-infested burrows was monitored over a 2-h period. In addition, tick attraction to different flow rates of carbon dioxide was monitored. Tests were conducted over a 15-mo period, during which seasonal effects on O. turicata response to CO2 were assessed. The efficacy of the baits was evaluated at night and in daytime. Ticks responded to dry ice baits placed up to 8 m away from the burrows. There was no significant difference in the total number of ticks attracted in a 1-h period using 500 to 2,000 ml CO2/min. At night, ticks were attracted to CO2 bits throughout the year except in December and January. By contrast, ticks were attracted to CO2 baits during daytime only between May and mid-December. PMID:1903452

  8. Burrowing hard corals occurring on the sea floor since 80 million years ago.

    PubMed

    Sentoku, Asuka; Tokuda, Yuki; Ezaki, Yoichi

    2016-01-01

    We describe a previously unknown niche for hard corals in the small, bowl-shaped, solitary scleractinian, Deltocyathoides orientalis (Family Turbinoliidae), on soft-bottom substrates. Observational experiments were used to clarify how the sea floor niche is exploited by turbinoliids. Deltocyathoides orientalis is adapted to an infaunal mode of life and exhibits behaviours associated with automobility that include burrowing into sediments, vertical movement through sediments to escape burial, and recovery of an upright position after being overturned. These behaviours were achieved through repeated expansion and contraction of their peripheral soft tissues, which constitute a unique muscle-membrane system. Histological analysis showed that these muscle arrangements were associated with deeply incised inter-costal spaces characteristic of turbinoliid corals. The oldest known turbinoliid, Bothrophoria ornata, which occurred in the Cretaceous (Campanian), also possessed a small, conical skeleton with highly developed costae. An infaunal mode of life became available to turbinoliids due to the acquisition of automobility through the muscle-membrane system at least 80 million years ago. The newly discovered active burrowing strategies described herein provide new insights into the use of an unattached mode of life by corals inhabiting soft-bottom substrates throughout the Phanerozoic. PMID:27074813

  9. Effectiveness of voluntary habitat stewardship in conserving grassland: case of operation burrowing owl in Saskatchewan.

    PubMed

    Warnock, Robert G; Skeel, Margaret A

    2004-03-01

    There have been no published performance evaluations of nongovernmental, voluntary habitat stewardship programs. The Operation Burrowing Owl (OBO) stewardship program, initiated in 1987, was evaluated for its effectiveness in conservation of grassland habitat during 1986-1993. The 108 OBO sites from 1987 to 88 and 98 randomly selected non-OBO sites that were grassland in 1986 in the Regina-Weyburn, Saskatchewan study area were classified by size and agricultural soil suitability. By 1993, 41 (38%) of the 108 OBO sites had been withdrawn from the program. The 1986 area of grassland was compared with grassland area calculated from digitized 1993 LANDSAT imagery. A correction for satellite inaccuracies was determined. Grassland retention in 1993 was significantly higher at OBO sites (66%) than at random sites (49%), demonstrating that the OBO voluntary program effectively conserved habitat. Also, grassland retention was significantly lower on sites with better agricultural soils, and for sites <12 ha in size. Site type (OBO or random), size and their interaction, followed by agricultural soil suitability, had the greatest effects on grassland retention. During an era of accelerated grassland loss, OBO strongly and positively (statistically significant) affected conservation of grassland sites most at risk: sites <12 ha in size and with good to excellent agricultural soils. This suggests that grassland conservation efforts focus on vulnerable sites (small size and/or good agricultural soils) to provide nesting habitat for burrowing owls. Our study demonstrates that a voluntary stewardship program can significantly increase conservation of habitat. PMID:15037954

  10. Can pocket gopher burrowing explain the long-term evolution of uplifted marine terrace scarps?

    NASA Astrophysics Data System (ADS)

    Loso, M. G.; Anderson, R. S.; Doak, D. F.

    2009-12-01

    For over a century, geomorphologists have sought to understand and model the mechanisms that control long-term evolution of soil-mantled hillslopes. Early workers acknowledged the importance of biological processes like soil anchoring by plant roots and bioturbation by burrowing animals, but only recently have substantial efforts been made to incorporate these factors into quantitative models. Several of these recent efforts have focused on the effects of burrowing by pocket gophers (Thomomys bottae). Field studies have documented the impressive volumes of sediment moved by these common fossorial mammals, and hillslope evolution models that implicitly reflect gopher activity (for example in sediment transport equations that are nonlinear functions of slope and soil depth) are increasingly successful in reproducing the steady-state form of gophered landscapes. But are gopher burrows simply one among many effective slope transport processes, or in some landscapes might they be—as some have suggested—the primary agent of sediment transport? To answer this question, we use a combination of field measurements, published data, and numerical modeling to determine whether modern rates of gopher-induced sediment transport are sufficient, over the long-term, to explain the observed evolution of scarps that separate a flight of four tectonically uplifted marine terraces north of Santa Cruz, California. The terraces are well-dated and the initial forms of the scarps—all former sea cliffs—are well constrained. We use two numerical models: a small-scale mound model that calculates the slope-dependent transport of sediment by a single gopher burrow, and a large-scale hillslope model that relies on a given distribution of gopher mounds to simulate the long-term evolution of these scarps from rocky sea cliffs to gentle, soil-mantled hillslopes. Our mound model accounts for the orientation and dimensions of a subterranean foraging tunnel and its associated

  11. 15 CFR 8a.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Recruitment. 8a.310 Section 8a.310... in Admission and Recruitment Prohibited § 8a.310 Recruitment. (a) Nondiscriminatory recruitment. A... recruitment and admission of students. A recipient may be required to undertake additional recruitment...

  12. 14 CFR 1253.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Recruitment. 1253.310 Section 1253.310... in Admission and Recruitment Prohibited § 1253.310 Recruitment. (a) Nondiscriminatory recruitment. A... recruitment and admission of students. A recipient may be required to undertake additional recruitment...

  13. 6 CFR 17.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Recruitment. 17.310 Section 17.310 Domestic... in Admission and Recruitment Prohibited § 17.310 Recruitment. (a) Nondiscriminatory recruitment. A... recruitment and admission of students. A recipient may be required to undertake additional recruitment...

  14. 41 CFR 101-4.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Recruitment. 101-4.310... Admission and Recruitment Prohibited § 101-4.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient... recruitment and admission of students. A recipient may be required to undertake additional recruitment...

  15. 28 CFR 54.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Recruitment. 54.310 Section 54.310... in Admission and Recruitment Prohibited § 54.310 Recruitment. (a) Nondiscriminatory recruitment. A... recruitment and admission of students. A recipient may be required to undertake additional recruitment...

  16. Teachers, Recruitment and the Law

    ERIC Educational Resources Information Center

    Degazon-Johnson, Roli

    2007-01-01

    This article offers a critical review and evaluation of the statutory environment in which recruitment agencies and businesses ply their trade in the United Kingdom (UK), with specific reference to the employment of overseas teachers. It focuses especially on teachers recruited from the Commonwealth over the period 1999-2005, a significant time…

  17. Resources for Outreach and Recruitment

    ERIC Educational Resources Information Center

    Johns, Charles E.

    1975-01-01

    On the premise that outreach and recruitment need to be seen as concomitants of quality education, the author suggests that both internal and external benefits can be derived from utilizing the natural constituencies of the institution--faculty, students, and alumni--before turning to private consulting agencies in business to recruit students.…

  18. Fast-Track Teacher Recruitment.

    ERIC Educational Resources Information Center

    Grant, Franklin Dean

    2001-01-01

    Schools need a Renaissance human-resources director to implement strategic staffing and fast-track teacher-recruitment plans. The HR director must attend to customer satisfaction, candidate supply, web-based recruitment possibilities, stabilization of newly hired staff, retention of veteran staff, utilization of retired employees, and latest…

  19. Diversity employment and recruitment sources

    SciTech Connect

    Not Available

    1994-08-01

    Effective human resources management has been identified as one of four critical success factors in the Department of Energy Strategic Plan. The Plan states relative to this factor: ``The Department seeks greater alignment of resources with agency priorities and increased diversification of the workforce, including gender, ethnicity, age, and skills. This diversification will bring new thinking and perspectives that heretofore have not had a voice in departmental decision-making.`` This Guide has been developed as a key tool to assist Department of Energy management and administrative staff in achieving Goal 2 of this critical success factor, which is to ``Ensure a diverse and talented workforce.`` There are numerous sources from which to recruit minorities, women and persons with disabilities. Applying creativity and proactive effort, using traditional and non-traditional approaches, and reaching out to various professional, academic and social communities will increase the reservoir of qualified candidates from which to make selections. In addition, outreach initiatives will undoubtedly yield further benefits such as a richer cultural understanding and diversity awareness. The resource listings presented in this Guide are offered to encourage active participation in the diversity recruitment process. This Guide contains resource listings by state for organizations in the following categories: (1) African American Recruitment Sources; (2) Asian American/Pacific Islander Recruitment Sources; (3) Hispanic Recruitment Sources; (4) Native American/Alaskan Native Recruitment Sources; (5) Persons with Disabilities Recruitment Sources; and (6) Women Recruitment Sources.

  20. Recruiting 4-H Volunteer Leaders.

    ERIC Educational Resources Information Center

    National Four-H Club Foundation, Washington, DC.

    The guide is intended to assist 4-H Club extension workers in recruiting volunteer adult and youth leaders. It discusses: why volunteers serve (organizational identity, desire to serve, involvement of other family members, future opportunities and obligations, community status, self interest, and public opinion); how to recruit (person-to-person…

  1. Three Keys to Better Recruiting

    ERIC Educational Resources Information Center

    Brazington, Alicia

    2012-01-01

    Recruitment is an expensive business: In 2010-2011, the median cost to recruit an undergraduate was $2,185 among private colleges and universities, according to Noel-Levitz, an enrollment management consultancy. In these tough fiscal times, admissions departments are under pressure to keep those costs down even as they pursue higher enrollment and…

  2. The College Recruiters' Quick Guide

    ERIC Educational Resources Information Center

    Holleman, Dewey

    2005-01-01

    The College Recruiters' Quick Guide provides an orientation to Recruitment responsibilities for new admissions professionals and those contemplating a career in college admissions. It is organized to give the reader a quick orientation and down-to-earth advice about what is involved in the admissions profession. This short publication defines the…

  3. Recruiting Literature: Is It Adequate?

    ERIC Educational Resources Information Center

    Stantial, Linda; And Others

    1979-01-01

    College students seeking employment in today's work world, who have questions about work environments which might be consistent with personal skills, interests, and values, turn to company recruiting literature. A recent study reveals that the information students and college personnel want from recruiting literature is not the information they…

  4. Making the Most of Recruiters.

    ERIC Educational Resources Information Center

    Gurney, Darrell W.

    This chapter provides an overview of the role and responsibilities of a recruiter or headhunter, and specifically how those responsibilities differ from those of career counselors, coaches, resume writers, or unemployment office workers. The mentalities of both the recruiter and employee are also explored. The benefits of using a headhunter for…

  5. Recruit and ADVANCE

    NASA Astrophysics Data System (ADS)

    Rosser, Sue V.

    2007-04-01

    Beginning in 2001, the National Science Foundation launched the ADVANCE Initiative, which has now awarded more than 70 million to some thirty institutions for transformations to advance women. Results of studies on how to attract and retain women students and faculty underpinned our ADVANCE Institutional Transformation grant funded by the NSF for 3.7 million for five years, beginning in 2001. As co-principal investigator on this grant, I insured that this research informed the five major threads of the grant: 1) Four termed ADVANCE professors to mentor junior women faculty in each college; 2) Collection of MIT-Report-like data indicators to assess whether advancement of women really occurs during and after the institutional transformation undertaken through ADVANCE; 3) Family-friendly policies and practices to stop the tenure clock and provide active service, modified duties, lactation stations and day care; 4) Mini-retreats to facilitate access for tenure-track women faculty to male decision-makers and administrators for informal conversations and discussion on topics important to women faculty; 5) Removal of subtle gender, racial, and other biases in promotion and tenure. The dynamic changes resulting from the grant in quality of mentoring, new understanding of promotion and tenure, numbers of women retained and given endowed chairs, and emergence of new family friendly policies gave me hope for genuine diversification of leadership in science and technology. As the grant funding ends, the absence of NSF prestige and monitoring, coupled with a change in academic leadership at the top, provide new challenges for institutionalization, recruitment, and advancement of women into leadership positions in science and engineering.

  6. Effect of Feeding by a Burrower Bug, Pangaeus bilineatus (Say) (Heteroptera: Cydnidae), on Peanut Flavor and Oil Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract A burrower bug, Pangaeus bilineatus (Say) (Heteroptera: Cydnidae), is known to feed extensively on peanut, Arachis hypogaea L., pods; particularly under certain reduced tillage production conditions. These bugs produce a strong odor when infested peanuts are uprooted, and previous anecdot...

  7. Habitat and Burrow System Characteristics of the Blind Mole Rat Spalax galili in an Area of Supposed Sympatric Speciation

    PubMed Central

    Lövy, Matěj; Šklíba, Jan; Hrouzková, Ema; Dvořáková, Veronika; Nevo, Eviatar; Šumbera, Radim

    2015-01-01

    A costly search for food in subterranean rodents resulted in various adaptations improving their foraging success under given ecological conditions. In Spalax ehrenbergi superspecies, adaptations to local ecological conditions can promote speciation, which was recently supposed to occur even in sympatry at sites where two soil types of contrasting characteristics abut each other. Quantitative description of ecological conditions in such a site has been, nevertheless, missing. We measured characteristics of food supply and soil within 16 home ranges of blind mole rats Spalax galili in an area subdivided into two parts formed by basaltic soil and pale rendzina. We also mapped nine complete mole rat burrow systems to compare burrowing patterns between the soil types. Basaltic soil had a higher food supply and was harder than rendzina even under higher moisture content and lower bulk density. Population density of mole rats was five-times lower in rendzina, possibly due to the lower food supply and higher cover of Sarcopoterium shrubs which seem to be avoided by mole rats. A combination of food supply and soil parameters probably influences burrowing patterns resulting in shorter and more complex burrow systems in basaltic soil. PMID:26192762

  8. Comparison of hydraulics and particle removal efficiencies in a mixed cell raceway and burrows pond rearing system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We compared the hydrodynamics of replicate experimental mixed cell and replicate standard Burrows pond rearing systems at the Dworshak National Fish Hatchery, ID, in an effort to identify methods for improved solids removal. We measured and compared the hydraulic residence time, particle removal eff...

  9. The Effect of Sand Particle Size on the Burrowing Ability of the Beach Mysid Gastrosaccus psammodytes Tattersall

    NASA Astrophysics Data System (ADS)

    Nel, R.; McLachlan, A.; Winter, D.

    1999-05-01

    Laboratory studies on the burrowing rates of the mysid shrimp, Gastrosaccus psammodytes , in a series of well-sorted sediments, determined whether (1) burial times were dependent on grain size and (2) if natural population distribution may be influenced by grain size on beaches. Burial times were tested in nine well-sorted sediments with grain size ranging from 90 to 2000μm. Large individuals (i.e. gravid females) were used. G. psammodytes burrowed fastest in 125-1000μm sand with mean burial times less than 1·6s. Burial time increased to approximately 2s in 90-125μm sand. G. psammodytes could not burrow in grain sizes coarser than 1000μm. G. psammodytes has been reported to occur on beaches with grain sizes ranging from 90 to 500μm but are uncommon on beaches with coarser sand. It appears that population distribution may be influenced by grain size that is probably not related to the animals' burial time ability, but rather their inability to burrow completely into coarse sand. Indirectly, grain size may also influence the morphodynamic state of a beach and therefore food availability since coarse-grained beaches tend to be reflective with little surf production.

  10. Distributional changes in the western Burrowing Owl (Athene cunicularia hypugaea) in North America from 1967 to 2008

    USGS Publications Warehouse

    Macias-Duarte, Alberto; Conway, Courtney J.

    2015-01-01

    The quantification of shifts in bird distributions in response to climate change provides an opportunity to gain a deeper understanding of the processes that influence species persistence. We used data from the North American Breeding Bird Survey (BBS) to document changes in the distributional limits of the western Burrowing Owl (Athene cunicularia hypugaea) from 1967 to 2008. We used logistic regression to model presence probability (p) as a function of longitude, latitude, and year. We modeled a linear trend in logit(p) through time with slope and intercept modeled as a double Fourier series of longitude and latitude. We found that the western Burrowing Owl has experienced an intriguing southward shift in the northern half of its breeding range, contrary to what is predicted by most species niche models and what has been observed for many other species in North America. The breeding range of the Burrowing Owl has been shrinking near its northern, western, and eastern edges. Our model detected the population declines that were observed in California and eastern Washington, in locations where maps based on route-specific estimating equations had predicted significant population increases. We suggest that the northern boundary of the breeding distribution of the western Burrowing Owl has contracted southward and the southern boundary of the species' breeding distribution has expanded southward into areas of northern Mexico that were formerly used only by wintering migrants.

  11. Comparison of hydraulics and particle removal efficiencies in a mixed cell raceway and Burrows pond rearing system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We compared the hydrodynamics of replicate experimental mixed cell and replicate standard Burrows pond rearing systems at the Dworshak National Fish Hatchery, ID, in an effort to identify methods for improved solids removal. We measured and compared the hydraulic residence time, particle removal eff...

  12. Habitat and Burrow System Characteristics of the Blind Mole Rat Spalax galili in an Area of Supposed Sympatric Speciation.

    PubMed

    Lövy, Matěj; Šklíba, Jan; Hrouzková, Ema; Dvořáková, Veronika; Nevo, Eviatar; Šumbera, Radim

    2015-01-01

    A costly search for food in subterranean rodents resulted in various adaptations improving their foraging success under given ecological conditions. In Spalax ehrenbergi superspecies, adaptations to local ecological conditions can promote speciation, which was recently supposed to occur even in sympatry at sites where two soil types of contrasting characteristics abut each other. Quantitative description of ecological conditions in such a site has been, nevertheless, missing. We measured characteristics of food supply and soil within 16 home ranges of blind mole rats Spalax galili in an area subdivided into two parts formed by basaltic soil and pale rendzina. We also mapped nine complete mole rat burrow systems to compare burrowing patterns between the soil types. Basaltic soil had a higher food supply and was harder than rendzina even under higher moisture content and lower bulk density. Population density of mole rats was five-times lower in rendzina, possibly due to the lower food supply and higher cover of Sarcopoterium shrubs which seem to be avoided by mole rats. A combination of food supply and soil parameters probably influences burrowing patterns resulting in shorter and more complex burrow systems in basaltic soil. PMID:26192762

  13. PARTICLE REMOVAL RATES BY THE MUD SHRIMP UPOGEBIA PUGETTENSIS, ITS BURROW, AND A COMMENSAL CLAM: EFFECTS ON ESTUARINE PHYTOPLANKTON ABUNDANCE

    EPA Science Inventory

    The burrowing shrimp Upogebia pugettensis is an abundant intertidal inhabitant of Pacific Northwest bays and estuaries where it lives commensally with the bivalve Cryptomya californica. Suspension-feeding activities by the shrimp and by its commensal clam, as well as particle se...

  14. Comparison of modified burrows wheeler transform with JPEG and JPEG2000 for image compression

    NASA Astrophysics Data System (ADS)

    Shabani, Sonia; Zolghadrasli, Alireza

    2012-01-01

    In this research we present a new method for image compression which is a combination of lossy and lossless image coder .In lossy part we use a 3-level decomposition of discrete wavelet transform with hard threshold technique. lossless image coding part is Burrows Wheeler Transform (BWT) which has received considerable attention in recent years because of its simplicity and effectiveness. The BWT is used with other additional methods of image compression such as, MTF, RLE and entropy coding algorithms. the effectiveness of over method is presented and compare with JPEG and JPEG2000 for different images concidering criteria such as PSNR ,Compression Ratio (CR) and images quality(HVS) in our future works we use BWT with other source coding algorithm such as Lempel-Ziv and different mother function for DWT.

  15. Sporothrix schenckii sensu stricto isolated from soil in an armadillo's burrow.

    PubMed

    Rodrigues, Anderson Messias; Bagagli, Eduardo; de Camargo, Zoilo Pires; Bosco, Sandra de Moraes Gimenes

    2014-04-01

    Sporotrichosis is a polymorphic disease of man and animals caused by traumatic implantation of propagules into the skin and subcutaneous tissue. Pathogenic species includes S. brasiliensis, S. schenckii, S. globosa and S. luriei. The disease is remarkable for its occurrence as sapronoses and/or zoonosis outbreaks in tropical and subtropical areas; although, the ecology of the clinical clade is still puzzling. Here, we describe an anamorphic Sporothrix strain isolated from soil in an armadillo's burrow, which was located in a hyper endemic area of Paracoccidioidomycosis in Brazil. This isolate was identified as S. schenckii sensu stricto (Clade IIa) based on morphological and physiological characteristics and phylogenetic analyses of calmodulin sequences. We then discuss the role of the nine-banded armadillo Dasypus novemcinctus as a natural carrier of Sporothrix propagules to better understand Sporothrix sources in nature and reveal essential aspects about the pathogen's eco-epidemiology. PMID:24577793

  16. Creeping hair: an isolated hair burrowing in the uppermost dermis resembling larva migrans.

    PubMed

    Sakai, Rie; Higashi, Kushio; Ohta, Miyuki; Sugimoto, Yasushi; Ikoma, Yukiko; Horiguchi, Yuji

    2006-01-01

    A 55-year-old Japanese male presented with a slowly moving linear erythema that looked like an eruption of creeping disease, or cutaneous larva migrans. The eruption extended linearly along Langer's line of the lateral side of the abdomen to the lower back, leaving wave-like erythema. In the top third of the erythematous eruption, close examination demonstrated a black thin line, which was revealed to be a hair shaft by a shallow incision of the skin. After removal of the hair, the eruption diminished immediately, leaving a slight pigmentation. An ingrown pubic hair seemed to have migrated with the lower end forward along Langer's line, because of the arrangement of hair cuticle and the force of body motion. Linearly moving erythematous eruptions that look like that of larva migrans should be differentiated from creeping hair by close examination detecting burrowing hair. PMID:17033177

  17. Patterns of surface burrow plugging in a colony of black-tailed prairie dogs occupied by black-footed ferrets

    USGS Publications Warehouse

    Eads, D.A.; Biggins, D.E.

    2012-01-01

    Black-tailed prairie dogs (Cynomys ludovicianus) can surface-plug openings to a burrow occupied by a black-footed ferret (Mustela nigripes). At a coarse scale, surface plugs are more common in colonies of prairie dogs occupied by ferrets than in colonies without ferrets. However, little is known about spatial and temporal patterns of surface plugging in a colony occupied by ferrets. In a 452-ha colony of black-tailed prairie dogs in South Dakota, we sampled burrow openings for surface plugs and related those data to locations of ferrets observed during spotlight surveys. Of 67,574 burrow openings in the colony between June and September 2007, 3.7% were plugged. In a colony-wide grid of 80 m × 80 m cells, the occurrence of surface plugging (≥1 opening plugged) was greater in cells used by ferrets (93.3% of cells) than in cells not observably used by ferrets (70.6%). Rates of surface plugging (percentages of openings plugged) were significantly higher in cells used by ferrets (median = 3.7%) than in cells without known ferret use (median = 3.2%). Also, numbers of ferret locations in cells correlated positively with numbers of mapped surface plugs in the cells. To investigate surface plugging at finer temporal and spatial scales, we compared rates of surface plugging in 20-m-radius circle-plots centered on ferret locations and in random plots 1–4 days after observing a ferret (Jun–Oct 2007 and 2008). Rates of surface plugging were greater in ferret-plots (median = 12.0%) than in random plots (median = 0%). For prairie dogs and their associates, the implications of surface plugging could be numerous. For instance, ferrets must dig to exit or enter plugged burrows (suggesting energetic costs), and surface plugs might influence microclimates in burrows and consequently influence species that cannot excavate soil (e.g., fleas that transmit the plague bacterium Yersinia pests).

  18. Recruitment Maneuvers and PEEP Titration.

    PubMed

    Hess, Dean R

    2015-11-01

    The injurious effects of alveolar overdistention are well accepted, and there is little debate regarding the importance of pressure and volume limitation during mechanical ventilation. The role of recruitment maneuvers is more controversial. Alveolar recruitment is desirable if it can be achieved, but the potential for recruitment is variable among patients with ARDS. A stepwise recruitment maneuver, similar to an incremental PEEP titration, is favored over sustained inflation recruitment maneuvers. Many approaches to PEEP titration have been proposed, and the best method to choose the most appropriate level for an individual patient is unclear. A PEEP level should be selected that balances alveolar recruitment against overdistention. The easiest approach to select PEEP might be according to the severity of the disease: 5-10 cm H2O PEEP in mild ARDS, 10-15 cm H2O PEEP in moderate ARDS, and 15-20 cm H2O PEEP in severe ARDS. Recruitment maneuvers and PEEP should be used within the context of lung protection and not just as a means of improving oxygenation. PMID:26493593

  19. Linking Microbial Enzymatic Activities and Functional Diversity of Soil around Earthworm Burrows and Casts

    PubMed Central

    Lipiec, Jerzy; Frąc, Magdalena; Brzezińska, Małgorzata; Turski, Marcin; Oszust, Karolina

    2016-01-01

    The aim of this work was to evaluate the effect of earthworms (Lumbricidae) on the enzymatic activity and microbial functional diversity in the burrow system [burrow wall (BW) 0–3 mm, transitional zone (TZ) 3–7 mm, bulk soil (BS) > 20 mm from the BW] and cast aggregates of a loess soil under a pear orchard. The dehydrogenase, β-glucosidase, protease, alkaline phosphomonoesterase, and acid phosphomonoesterase enzymes were assessed using standard methods. The functional diversity (catabolic potential) was assessed using the Average Well Color Development and Richness Index following the community level physiological profiling from Biolog Eco Plates. All measurements were done using soil from each compartment immediately after in situ sampling in spring. The enzymatic activites including dehydrogenase, protease, β-glucosidase and alkaline phosphomonoesterase were appreciably greater in the BW or casts than in BS and TZ. Conversely, acid phosphomonoesterase had the largest value in the BS. Average Well Color Development in both the TZ and the BS (0.98–0.94 A590 nm) were more than eight times higher than in the BWs and casts. The lowest richness index in the BS (15 utilized substrates) increased by 86–113% in all the other compartments. The PC1 in principal component analysis mainly differentiated the BWs and the TZ. Utilization of all substrate categories was the lowest in the BS. The PC2 differentiated the casts from the other compartments. The enhanced activity of a majority of the enzymes and increased microbial functional diversity in most earthworm-influenced compartments make the soils less vulnerable to degradation and thus increases the stability of ecologically relevant processes in the orchard ecosystem. PMID:27625645

  20. Borrelia infection in small mammals in West Africa and its relationship with tick occurrence inside burrows.

    PubMed

    Diatta, Georges; Duplantier, Jean-Marc; Granjon, Laurent; Bâ, Khalilou; Chauvancy, Gilles; Ndiaye, Mady; Trape, Jean-François

    2015-12-01

    Tick-borne relapsing fever (TBRF) is a zoonotic disease caused by several Borrelia species transmitted to humans by Ornithodoros tick vectors. In West Africa, Borrelia crocidurae is a common cause of disease in many rural populations. Small mammals act as reservoirs of infection. We report here the results of surveys that investigated the occurrence of B. crocidurae infection in rodents and insectivores from eight countries of West and Central Africa. Animals were identified at the species level and tested for Borrelia either by examination of thick blood film, intra-peritoneal inoculation of blood or brain tissues into laboratory mice, or by molecular techniques. A total of 4358 small mammals belonging to 38 species and 7 families were collected, including 3225 specimens collected in areas where the occurrence of Ornithodoros sonrai tick in rodent burrows was documented, and 1133 in areas where this tick was absent. In areas with O. sonrai, Borrelia infection was demonstrated in 287 of 3109 (9.2%) small mammals tested, and none was documented in 1004 animals tested from other areas. There was no relationship between the occurrence of Rhipicephalus, Hyaloma and Argas ticks in burrows and the distribution of Borrelia infection in small mammals. The 287 specimens infected by Borrelia belonged to 15 rodent and shrew species, including three Saharo-Sahelian species - Gerbillus gerbillus, Gerbillus occiduus and Gerbillus tarabuli - identified as reservoirs for TBRF with a distribution restricted to this area. In Sudan and Sudano-Sahelian areas, Arvicanthis niloticus, Mastomys erythroleucus and Mastomys huberti were the main reservoir of infection. Although most small mammals species collected had a large distribution in West and Central Africa, the fact that only animals collected in areas with O. sonrai were found infected suggest that this tick is the only vector of TBRF in rodents and insectivores in this part of Africa. PMID:26327444

  1. [Aerosol deposition in nasal passages of burrowing and ground rodents when breathing dust-laden air].

    PubMed

    Moshkin, M P; Petrovskiĭ, D V; Akulov, A E; Romashchenko, A V; Gerlinskaia, L A; Muchnaia, M I; Ganimedov, V L; Sadovskiĭ, A S; Savelov, A A; Koptiug, I V; Troitskiĭ, S Iu; Bukhtiiarov, V I; Kolchanov, N A; Sagdeev, R Z; Fomin, V M

    2014-01-01

    In subterranean rodents, which dig down the passages with frontal teeth, adaptation to the underground mode of life presumes forming of mechanisms that provide protection against inhaling dust particles of different size when digging. One of such mechanisms can be specific pattern of air flow organization in the nasal cavity. To test this assumption, comparative study of geometry and aerodynamics of nasal passages has been conducted with regard to typical representative of subterranean rodents, the mole vole, and a representative of ground rodents, the house mouse. Numerical modeling of air flows and deposition of micro- and nanoparticle aerosols indicates that sedimentation of model particles over the whole surface of nasal cavity is higher in mole vole than in house mouse. On the contrary, particles deposition on the surface of olfactory epithelium turns out to be substantially less in the burrowing rodent as compared to the ground one. Adaptive significance of the latter observation has been substantiated by experimental study on the uptake ofnanoparticles of hydrated manganese oxide MnO x (H2O)x and Mn ions from nasal cavity into brain. It has been shown with use of magnetic resonance tomography method that there is no difference between studied species with respect to intake of particles or ions by olfactory bulb when they are introduced intranasally. Meanwhile, when inhaling nanoparticle aerosol of MnCl2, deposition of Mn in mouse's olfactory bulbs surpasses markedly that in vole's bulbs. Thereby, the morphology of nasal passages as a factor determining the aerodynamics of upper respiratory tract ensures for burrowing rodents more efficient protection of both lungs and brain against inhaled aerosols than for ground ones. PMID:25771679

  2. Estimates of density, detection probability, and factors influencing detection of burrowing owls in the Mojave Desert

    USGS Publications Warehouse

    Crowe, D.E.; Longshore, K.M.

    2010-01-01

    We estimated relative abundance and density of Western Burrowing Owls (Athene cunicularia hypugaea) at two sites in the Mojave Desert (200304). We made modifications to previously established Burrowing Owl survey techniques for use in desert shrublands and evaluated several factors that might influence the detection of owls. We tested the effectiveness of the call-broadcast technique for surveying this species, the efficiency of this technique at early and late breeding stages, and the effectiveness of various numbers of vocalization intervals during broadcasting sessions. Only 1 (3) of 31 initial (new) owl responses was detected during passive-listening sessions. We found that surveying early in the nesting season was more likely to produce new owl detections compared to surveying later in the nesting season. New owls detected during each of the three vocalization intervals (each consisting of 30 sec of vocalizations followed by 30 sec of silence) of our broadcasting session were similar (37, 40, and 23; n 30). We used a combination of detection trials (sighting probability) and double-observer method to estimate the components of detection probability, i.e., availability and perception. Availability for all sites and years, as determined by detection trials, ranged from 46.158.2. Relative abundance, measured as frequency of occurrence and defined as the proportion of surveys with at least one owl, ranged from 19.232.0 for both sites and years. Density at our eastern Mojave Desert site was estimated at 0.09 ?? 0.01 (SE) owl territories/km2 and 0.16 ?? 0.02 (SE) owl territories/km2 during 2003 and 2004, respectively. In our southern Mojave Desert site, density estimates were 0.09 ?? 0.02 (SE) owl territories/km2 and 0.08 ?? 0.02 (SE) owl territories/km 2 during 2004 and 2005, respectively. ?? 2010 The Raptor Research Foundation, Inc.

  3. Linking Microbial Enzymatic Activities and Functional Diversity of Soil around Earthworm Burrows and Casts.

    PubMed

    Lipiec, Jerzy; Frąc, Magdalena; Brzezińska, Małgorzata; Turski, Marcin; Oszust, Karolina

    2016-01-01

    The aim of this work was to evaluate the effect of earthworms (Lumbricidae) on the enzymatic activity and microbial functional diversity in the burrow system [burrow wall (BW) 0-3 mm, transitional zone (TZ) 3-7 mm, bulk soil (BS) > 20 mm from the BW] and cast aggregates of a loess soil under a pear orchard. The dehydrogenase, β-glucosidase, protease, alkaline phosphomonoesterase, and acid phosphomonoesterase enzymes were assessed using standard methods. The functional diversity (catabolic potential) was assessed using the Average Well Color Development and Richness Index following the community level physiological profiling from Biolog Eco Plates. All measurements were done using soil from each compartment immediately after in situ sampling in spring. The enzymatic activites including dehydrogenase, protease, β-glucosidase and alkaline phosphomonoesterase were appreciably greater in the BW or casts than in BS and TZ. Conversely, acid phosphomonoesterase had the largest value in the BS. Average Well Color Development in both the TZ and the BS (0.98-0.94 A590 nm) were more than eight times higher than in the BWs and casts. The lowest richness index in the BS (15 utilized substrates) increased by 86-113% in all the other compartments. The PC1 in principal component analysis mainly differentiated the BWs and the TZ. Utilization of all substrate categories was the lowest in the BS. The PC2 differentiated the casts from the other compartments. The enhanced activity of a majority of the enzymes and increased microbial functional diversity in most earthworm-influenced compartments make the soils less vulnerable to degradation and thus increases the stability of ecologically relevant processes in the orchard ecosystem. PMID:27625645

  4. Bench-to-bedside review: Recruitment and recruiting maneuvers.

    PubMed

    Lapinsky, Stephen E; Mehta, Sangeeta

    2005-02-01

    In patients with acute respiratory distress syndrome (ARDS), the lung comprises areas of aeration and areas of alveolar collapse, the latter producing intrapulmonary shunt and hypoxemia. The currently suggested strategy of ventilation with low lung volumes can aggravate lung collapse and potentially produce lung injury through shear stress at the interface between aerated and collapsed lung, and as a result of repetitive opening and closing of alveoli. An 'open lung strategy' focused on alveolar patency has therefore been recommended. While positive end-expiratory pressure prevents alveolar collapse, recruitment maneuvers can be used to achieve alveolar recruitment. Various recruitment maneuvers exist, including sustained inflation to high pressures, intermittent sighs, and stepwise increases in positive end-expiratory pressure or peak inspiratory pressure. In animal studies, recruitment maneuvers clearly reverse the derecruitment associated with low tidal volume ventilation, improve gas exchange, and reduce lung injury. Data regarding the use of recruitment maneuvers in patients with ARDS show mixed results, with increased efficacy in those with short duration of ARDS, good compliance of the chest wall, and in extrapulmonary ARDS. In this review we discuss the pathophysiologic basis for the use of recruitment maneuvers and recent evidence, as well as the practical application of the technique. PMID:15693985

  5. 22 CFR 229.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Recruitment. 229.310 Section 229.310 Foreign... and Recruitment Prohibited § 229.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 229.300 through 229.310 apply shall not discriminate on the basis of sex in the recruitment...

  6. 49 CFR 25.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Recruitment. 25.310 Section 25.310 Transportation... Recruitment Prohibited § 25.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 25.300 through 25.310 apply shall not discriminate on the basis of sex in the recruitment and admission...

  7. 10 CFR 1042.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Recruitment. 1042.310 Section 1042.310 Energy DEPARTMENT... Recruitment Prohibited § 1042.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 1042.300 through 1042.310 apply shall not discriminate on the basis of sex in the recruitment and...

  8. LINKING HABITAT CHANGE AND NUTRIENT DYNAMICS: COMPARISON OF FOOD WEBS AND NITROGEN FLUXES IN BURROWING SHRIMP- AND OYSTER-DOMINATED HABITATS

    EPA Science Inventory

    Endemic thalassinid burrowing shrimps are simultaneously dominant ecosystem engineering species and economic pests within Pacific estuaries. Dense populations of two shrimps (Neotrypaea californiensis and Upogebia pugettensis) commonly occupy >75% of intertidal and shallow subti...

  9. The Distribution and Occurrence of Acholoë squamosa(Polychaeta: Polynoidae) a Commensal with the Burrowing Starfish Astropecten irregularis(Echinodermata: Asteroidea)

    NASA Astrophysics Data System (ADS)

    Freeman, S. M.; Richardson, C. A.; Seed, R.

    1998-07-01

    The distribution and abundance of Acholoë squamosa, a commensal with the burrowing starfish Astropecten irregularis, at 17 sites off the western and south-western coasts of the British Isles are described. A total of 4329 Astropectenand 3362 Acholoëwere examined. Population density of Astropectenranged from 5 to 592 individuals ha -1with higher densities typically associated with finer-grained sandy or muddy sediments. There was considerable inter-site variability in colonization rates with maximum colonization approaching 90%. The occurrence of Acholoëwas negatively correlated with the modal arm size of the host population and with water depth, factors which were themselves significantly correlated. Most adult worms occurred in the ambulacral grooves, and worms were sometimes observed with their head and anterior body region inside the mouth of the host, presumably feeding on stomach contents. Marked seasonal trends in abundance of the Astropectenpopulation were not accompanied by any comparable changes in the levels of colonization by Acholoë. Never more than one adult worm (i.e. >15 mm in length) occurred on the same starfish, indicating that intra-specific factors may control the distribution of Acholoë; multiple colonization comprised a single adult worm with up to three juveniles (i.e. worms <15 mm). In late autumn and late spring to early summer, newly recruited Acholoëwere found between the inferomarginal plates of the host where they were afforded protection by the over-arching ossicle spines. The sex ratio appeared to be strongly biased (20:1) towards females.

  10. The Perfect Burrow, but for What? Identifying Local Habitat Conditions Promoting the Presence of the Host and Vector Species in the Kazakh Plague System

    PubMed Central

    Wilschut, Liesbeth; Addink, Elisabeth; Ageyev, Vladimir; Yeszhanov, Aidyn; Sapozhnikov, Valerij; Belayev, Alexander; Davydova, Tania; Eagle, Sally; Begon, Mike

    2015-01-01

    Introduction The wildlife plague system in the Pre-Balkhash desert of Kazakhstan has been a subject of study for many years. Much progress has been made in generating a method of predicting outbreaks of the disease (infection by the gram negative bacterium Yersinia pestis) but existing methods are not yet accurate enough to inform public health planning. The present study aimed to identify characteristics of individual mammalian host (Rhombomys opimus) burrows related to and potentially predictive of the presence of R.opimus and the dominant flea vectors (Xenopsylla spp.). Methods Over four seasons, burrow characteristics, their current occupancy status, and flea and tick burden of the occupants were recorded in the field. A second data set was generated of long term occupancy trends by recording the occupancy status of specific burrows over multiple occasions. Generalised linear mixed models were constructed to identify potential burrow properties predictive of either occupancy or flea burden. Results At the burrow level, it was identified that a burrow being occupied by Rhombomys, and remaining occupied, were both related to the characteristics of the sediment in which the burrow was constructed. The flea burden of Rhombomys in a burrow was found to be related to the tick burden. Further larger scale properties were also identified as being related to both Rhombomys and flea presence, including latitudinal position and the season. Conclusions Therefore, in advancing our current predictions of plague in Kazakhstan, we must consider the landscape at this local level to increase our accuracy in predicting the dynamics of gerbil and flea populations. Furthermore this demonstrates that in other zoonotic systems, it may be useful to consider the distribution and location of suitable habitat for both host and vector species at this fine scale to accurately predict future epizootics. PMID:26325073

  11. Rapid seawater circulation through animal burrows in mangrove forests - A significant source of saline groundwater to the tropical coastal ocean

    NASA Astrophysics Data System (ADS)

    Clark, J. F.; Stieglitz, T. C.; Hancock, G. J.

    2010-12-01

    A common approach for quantifying rates of submarine groundwater discharge (SGD) to the coastal ocean is to use geochemical tracers that are part of the U- and Th-decay chains such as Rn-222 and short lived radium isotopes. These radionuclides are naturally enriched in groundwater relative to seawater and have well understood chemistries within the marine environment. They occur in both fresh (continental) and saline (marine) groundwaters and thus the water source is often ambiguous. Stieglitz (2005, Marine Pollution Bulletin 51, 51-59) has shown that some coastal areas within the Great Barrier Reef (GBR) lagoon (Australia) are enriched in the SGD tracer, Rn-222; he attributed this to four possible processes including the tidal flushing of mangrove forest floors. Here, we present a detailed investigation into the tidal circulation of seawater through animal burrows using Rn-222 and isotopes of radium in the Coral Creek mangrove forest, Hinchinbrook Island, Queensland, Australia. The study was conducted at the end of the dry season in a creek with no freshwater inputs. Significant export of radionuclides and salt from the forest into the creek indicates continuous tidally driven circulation through the burrows. Results demonstrate that the forest sediment is efficiently flushed, with a water flux of about 30 L/m2/ day of forest floor, which is equivalent to flushing about 10% of the total burrow volume per tidal cycle. Annual average circulation flux through mangrove forest floors are of the same order as annual river discharge in the central GBR. However, unlike the river discharge, the tidal circulation should be relatively stable throughout the year. This work documents the importance of animal burrows in maintaining productive sediments in these systems, and illustrates the physical process that supports large exports of organic and inorganic matter from mangrove forests to the coastal zone. It also illustrates the importance of considering saline groundwater

  12. Growth of the dune wintergreen ( Pyrola rotundifolia ssp. maritima) at Braunton Burrows in relation to weather factors

    NASA Astrophysics Data System (ADS)

    Hunt, R.; Hope-Simpson, J. F.; Snape, J. B.

    1985-12-01

    The dune wintergreen ( Pyrola rotundifolia ssp. maritima) is an evergreen perennial herb which has spread extensively in recent decades to, and on, various British dune systems including Braunton Burrows, N. Devon. Its multiplication is partly vegetative, by rhizomes bearing leaf rosettes. This study primarily concerns the relation between: (i) the growth of one particular invasive colony on Braunton Burrows, as shown by the numbers of living rosettes counted at midsummer from 1964 74 inclusive; and (ii) concurrent meteorological records made nearby. Monthly weather means were calculated on various quarterly bases. After de-trending the Pyrola data statistically, correlations were sought between the growth in numbers achieved in each year and the local air temperature (three bases), rainfall and duration of bright sunshine. While the annual increase in net numbers appears to have been unaffected by sunshine hours, this increase does seem to have been much diminished by cold nights, particularly in early spring and, though less strongly so, by low rainfall in the latter part of the preceding summer. Taking account of the performance of Pyrola in other habitats on the Burrows, it is suggested that the rainfall correlation may reflect the influence of atmospheric humidity rather than water supply to the roots. Local meteorological records over a 51-year period show combined temperature and rainfall conditions consistently favourable to Pyrola growth throughout a 5-year run to a degree which might be expected to occur in only three such runs out of every hundred. The favourable period (1957 61) occurred between the inferred first occurrence of Pyrola on the Burrows and its observed rapid spread.

  13. Burrowing seabird effects on invertebrate communities in soil and litter are dominated by ecosystem engineering rather than nutrient addition.

    PubMed

    Orwin, Kate H; Wardle, David A; Towns, David R; St John, Mark G; Bellingham, Peter J; Jones, Chris; Fitzgerald, Brian M; Parrish, Richard G; Lyver, Phil O'B

    2016-01-01

    Vertebrate consumers can be important drivers of the structure and functioning of ecosystems, including the soil and litter invertebrate communities that drive many ecosystem processes. Burrowing seabirds, as prevalent vertebrate consumers, have the potential to impact consumptive effects via adding marine nutrients to soil (i.e. resource subsidies) and non-consumptive effects via soil disturbance associated with excavating burrows (i.e. ecosystem engineering). However, the exact mechanisms by which they influence invertebrates are poorly understood. We examined how soil chemistry and plant and invertebrate communities changed across a gradient of seabird burrow density on two islands in northern New Zealand. Increasing seabird burrow density was associated with increased soil nutrient availability and changes in plant community structure and the abundance of nearly all the measured invertebrate groups. Increasing seabird densities had a negative effect on invertebrates that were strongly influenced by soil-surface litter, a positive effect on fungal-feeding invertebrates, and variable effects on invertebrate groups with diverse feeding strategies. Gastropoda and Araneae species richness and composition were also influenced by seabird activity. Generalized multilevel path analysis revealed that invertebrate responses were strongly driven by seabird engineering effects, via increased soil disturbance, reduced soil-surface litter, and changes in trophic interactions. Almost no significant effects of resource subsidies were detected. Our results show that seabirds, and in particular their non-consumptive effects, were significant drivers of invertebrate food web structure. Reductions in seabird populations, due to predation and human activity, may therefore have far-reaching consequences for the functioning of these ecosystems. PMID:26410032

  14. Fossil Worm Burrows Reveal Very Early Terrestrial Animal Activity and Shed Light on Trophic Resources after the End-Cretaceous Mass Extinction

    PubMed Central

    Chin, Karen; Pearson, Dean; Ekdale, A. A.

    2013-01-01

    The widespread mass extinctions at the end of the Cretaceous caused world-wide disruption of ecosystems, and faunal responses to the one-two punch of severe environmental perturbation and ecosystem collapse are still unclear. Here we report the discovery of in situ terrestrial fossil burrows from just above the impact-defined Cretaceous-Paleogene (K/Pg) boundary in southwestern North Dakota. The crisscrossing networks of horizontal burrows occur at the interface of a lignitic coal and silty sandstone, and reveal intense faunal activity within centimeters of the boundary clay. Estimated rates of sedimentation and coal formation suggest that the burrows were made less than ten thousand years after the end-Cretaceous impact. The burrow characteristics are most consistent with burrows of extant earthworms. Moreover, the burrowing and detritivorous habits of these annelids fit models that predict the trophic and sheltering lifestyles of terrestrial animals that survived the K/Pg extinction event. In turn, such detritus-eaters would have played a critical role in supporting secondary consumers. Thus, some of the carnivorous vertebrates that radiated after the K/Pg extinction may owe their evolutionary success to thriving populations of earthworms. PMID:23951041

  15. Fossil worm burrows reveal very early terrestrial animal activity and shed light on trophic resources after the end-cretaceous mass extinction.

    PubMed

    Chin, Karen; Pearson, Dean; Ekdale, A A

    2013-01-01

    The widespread mass extinctions at the end of the Cretaceous caused world-wide disruption of ecosystems, and faunal responses to the one-two punch of severe environmental perturbation and ecosystem collapse are still unclear. Here we report the discovery of in situ terrestrial fossil burrows from just above the impact-defined Cretaceous-Paleogene (K/Pg) boundary in southwestern North Dakota. The crisscrossing networks of horizontal burrows occur at the interface of a lignitic coal and silty sandstone, and reveal intense faunal activity within centimeters of the boundary clay. Estimated rates of sedimentation and coal formation suggest that the burrows were made less than ten thousand years after the end-Cretaceous impact. The burrow characteristics are most consistent with burrows of extant earthworms. Moreover, the burrowing and detritivorous habits of these annelids fit models that predict the trophic and sheltering lifestyles of terrestrial animals that survived the K/Pg extinction event. In turn, such detritus-eaters would have played a critical role in supporting secondary consumers. Thus, some of the carnivorous vertebrates that radiated after the K/Pg extinction may owe their evolutionary success to thriving populations of earthworms. PMID:23951041

  16. Facilitating Alzheimer disease research recruitment.

    PubMed

    Grill, Joshua D; Galvin, James E

    2014-01-01

    Alzheimer disease (AD) research faces challenges to successful enrollment, especially to clinical trials and biomarker studies. Failure to recruit the planned number of participants in a timely manner threatens the internal validity and success of clinical research, raising concerns about external validity and generalizability of results, and possibly leading to disparities in disease treatment. Methods to improve recruitment exist, but require varying levels of staff effort and financial resources, and evidence of effectiveness is often lacking or inconsistent. In this review, we summarize some of the available methods to improve AD research recruitment, the available literature to support or refute these strategies, and some of the experiences at the authors' AD Research Centers. We discuss the use of community-based participatory research principles and participant registries as a means to enhance research enrollment and increase diversity of research samples. PMID:24322484

  17. Failure to Burrow and Tunnel Reveals Roles for jim lovell in the Growth and Endoreplication of the Drosophila Larval Tracheae

    PubMed Central

    Qiang, Karen M.; Beckingham, Kathleen M.

    2016-01-01

    The Drosophila protein Jim Lovell (Lov) is a putative transcription factor of the BTB/POZ (Bric- a-Brac/Tramtrack/Broad/ Pox virus and Zinc finger) domain class that is expressed in many elements of the developing larval nervous system. It has roles in innate behaviors such as larval locomotion and adult courtship. In performing tissue-specific knockdown with the Gal4-UAS system we identified a new behavioral phenotype for lov: larvae failed to burrow into their food during their growth phase and then failed to tunnel into an agarose substratum during their wandering phase. We determined that these phenotypes originate in a previously unrecognized role for lov in the tracheae. By using tracheal-specific Gal4 lines, Lov immunolocalization and a lov enhancer trap line, we established that lov is normally expressed in the tracheae from late in embryogenesis through larval life. Using an assay that monitors food burrowing, substrate tunneling and death we showed that lov tracheal knockdown results in tracheal fluid-filling, producing hypoxia that activates the aberrant behaviors and inhibits development. We investigated the role of lov in the tracheae that initiates this sequence of events. We discovered that when lov levels are reduced, the tracheal cells are smaller, more numerous and show lower levels of endopolyploidization. Together our findings indicate that Lov is necessary for tracheal endoreplicative growth and that its loss in this tissue causes loss of tracheal integrity resulting in chronic hypoxia and abnormal burrowing and tunneling behavior. PMID:27494251

  18. A burrowing frog from the late Paleocene of Mongolia uncovers a deep history of spadefoot toads (Pelobatoidea) in East Asia.

    PubMed

    Chen, Jianye; Bever, Gaberiel S; Yi, Hong-Yu; Norell, Mark A

    2016-01-01

    Fossils are indispensible in understanding the evolutionary origins of the modern fauna. Crown-group spadefoot toads (Anura: Pelobatoidea) are the best-known fossorial frog clade to inhabit arid environments, with species utilizing a characteristic bony spade on their foot for burrowing. Endemic to the Northern Hemisphere, they are distributed across the Holarctic except East Asia. Here we report a rare fossil of a crown-group spadefoot toad from the late Paleocene of Mongolia. The phylogenetic analysis using both morphological and molecular information recovered this Asian fossil inside the modern North American pelobatoid clade Scaphiopodidae. The presence of a spade and the phylogenetic position of the new fossil frog strongly support its burrowing behavior. The late Paleocene age and other information suggestive of a mild climate cast doubt on the conventional assertion that burrowing evolved as an adaptation to aridity in spadefoot toads. Temporally and geographically, the new fossil provides the earliest record of Scaphiopodidae worldwide, and the only member of the group in Asia. Quantitative biogeographic analysis suggests that Scaphiopodidae, despite originating in North America, dispersed into East Asia via Beringia in the Early Cenozoic. The absence of spadefoot toads in East Asia today is a result of extinction. PMID:26750105

  19. A burrowing frog from the late Paleocene of Mongolia uncovers a deep history of spadefoot toads (Pelobatoidea) in East Asia

    PubMed Central

    Chen, Jianye; Bever, Gaberiel S.; Yi, Hong-Yu; Norell, Mark A.

    2016-01-01

    Fossils are indispensible in understanding the evolutionary origins of the modern fauna. Crown-group spadefoot toads (Anura: Pelobatoidea) are the best-known fossorial frog clade to inhabit arid environments, with species utilizing a characteristic bony spade on their foot for burrowing. Endemic to the Northern Hemisphere, they are distributed across the Holarctic except East Asia. Here we report a rare fossil of a crown-group spadefoot toad from the late Paleocene of Mongolia. The phylogenetic analysis using both morphological and molecular information recovered this Asian fossil inside the modern North American pelobatoid clade Scaphiopodidae. The presence of a spade and the phylogenetic position of the new fossil frog strongly support its burrowing behavior. The late Paleocene age and other information suggestive of a mild climate cast doubt on the conventional assertion that burrowing evolved as an adaptation to aridity in spadefoot toads. Temporally and geographically, the new fossil provides the earliest record of Scaphiopodidae worldwide, and the only member of the group in Asia. Quantitative biogeographic analysis suggests that Scaphiopodidae, despite originating in North America, dispersed into East Asia via Beringia in the Early Cenozoic. The absence of spadefoot toads in East Asia today is a result of extinction. PMID:26750105

  20. Recruiting Health Information Faculty: The Effects of Monetary Recruitment Incentives

    ERIC Educational Resources Information Center

    Winter, Paul A.; Logsdon, Marsha R.

    2004-01-01

    This paper addresses recruitment of Health Information faculty for community and technical colleges, an issue of crucial importance because many faculty hired during the enrollment boom of the 1960s are retiring. The design for this research was a factorial experiment, involving a two-way analysis of variance. The participants (N = 194) were…

  1. Effects of radiotransmitter necklaces on behaviors of adult male western burrowing owls

    USGS Publications Warehouse

    Chipman, E.D.; McIntyre, N.E.; Ray, J.D.; Wallace, M.C.; Boal, C.W.

    2007-01-01

    We studied the behavioral effects of necklace-style radiotransmitters on breeding male western burrowing owls (Athene cunicularia hypugaea) in 2 areas of northwestern Texas, USA, in 2004 and 2005. We tested the hypothesis that transmittered owls would spend time interacting with their necklaces and as a result spend less time in vigilance and resting activities than would nontransmittered owls. Nontransmittered owls (n = 6) spent significantly more time being vigilant (P = 0.007) than did transmittered owls (n = 3) in 2004, who spent significant amounts of time interacting with their necklaces. In 2005, behaviors of transmittered owls (n = 8) were significantly different (P < 0.001) from control individuals (n = 4), but behaviors did not vary consistently by treatment period (prenecklace vs. necklace vs. postnecklace periods). Behavioral activity budgets varied considerably among individuals. Although the owls spent a significant amount of time interacting with their necklaces, they appeared to habituate to the presence of the transmitters within a relatively short period (<1 week), and necklaces did not affect survivorship or fitness in the short-term.

  2. Recovery of burrowing mayflies (Ephemeroptera: Ephemeridae: Hexagenia) in western Lake Erie

    USGS Publications Warehouse

    Krieger, Kenneth A.; Schloesser, Don W.; Manny, Bruce A.; Trisler, Carmen E.; Heady, Susan E.; Ciborowski, Jan J.H.; Muth, Kenneth M.

    1996-01-01

    Burrowing mayflies (Hexagenia spp.) are native to western Lake Erie and were abundant until the 1950s, when they disappeared due to degraded water and sediment quality. Nymphs were absent from the sediments of most of western Lake Erie after the 1950s, although small, widely disjunct populations apparently persisted near shore. Sediment samples collected in 1993 revealed several small populations near the western and southern shores and beyond the mouths of the Detroit and Maumee rivers. A larger population was found in the southern island area, but nymphs were absent in the middle of the basin. By 1995, nymphs had spread throughout the western half and eastern end of the basin but remained absent from the middle of the basin. These data indicate thatHexagenia began recolonizing nearshore areas before offshore areas. Increasingly large swarms of winged Hexagenia on shore and over the lake between 1992 and 1994 further indicate that mayflies are recolonizing the basin. Factors that have permitted Hexageniarecovery in western Lake Erie probably include improved sediment and water quality attributed to pollution abatement programs implemented after the early 1970s, and perhaps environmental changes in the early 1990s attributed to effects of the exotic zebra mussel (Dreissena polymorpha).

  3. Differential risk perception of rural and urban Burrowing Owls exposed to humans and dogs.

    PubMed

    Cavalli, Matilde; Baladrón, Alejandro V; Isacch, Juan Pablo; Biondi, Laura M; Bó, María Susana

    2016-03-01

    Urban areas expose wildlife to an array of novel predators, amongst which, humans and dogs are highly frequent. Thus, wild animals living in urban areas are forced to invest more time and energy in defence behaviours, which depend on how the risk is perceived and assessed. We experimentally tested whether Burrowing owls coming from rural and urban habitats showed differences in behavioural responses when facing humans and domestic dogs. We measured flight initiation distances (FIDs), nest returning, and aggressiveness level when owls faced a human and a human with a dog walking towards them. Our results showed that urban owls recognise a human with a dog as a greater threat than a human alone, thus indicating that fear of domestic animals should be considered as affecting owls' settlement in cities and towns. On the other hand, rural owls perceived human and dogs as similar threats, but showed higher FIDs, less aggressiveness, and lower tendency to return to the nest than urban owls in both treatments. These findings emphasize the importance of modified habitats in modelling the response of urban and rural owls to predators and represent another step in the explanation of how wild animals assess and respond to threats associated with living in urbanized environments. PMID:26718884

  4. Thermal and hygric physiology of Australian burrowing mygalomorph spiders (Aganippe spp.).

    PubMed

    Mason, Leanda D; Tomlinson, Sean; Withers, Philip C; Main, Barbara Y

    2013-01-01

    This study investigated the standard metabolic rate (SMR) and evaporative water loss (EWL) responses of three Australian trapdoor-constructing mygalomorph spider species, two undescribed arid-zone species (Aganippe 'Tropicana A' and A. 'Tropicana B') and a mesic-dwelling species (A. rhaphiduca) to acute environmental regimes of temperature and relative humidity. There were significant effects of species, temperature, and relative humidity on SMR. SMR was lower for A. raphiduca than both A. 'Tropicana' spp. with no difference between the two A. 'Tropicana' spp. Metabolic rate increased at higher temperature and relative humidity for all three species. There were significant effects of species, temperature, and relative humidity on EWL. The mesic Aganippe species had a significantly higher EWL than either arid Tropicana species. EWL was significantly higher at lower relative humidity. Our results suggest an environmental effect on EWL but not SMR, and that mygalomorphs are so vulnerable to desiccation that the burrow provides a crucial refuge to ameliorate the effects of low environmental humidity. We conclude that mygalomorphs are highly susceptible to disturbance, and are of high conservation value as many are short-range endemics. PMID:22911375

  5. Egg production of the burrowing shrimp Callichirus seilacheri (Bott 1955) (Decapoda, Callianassidae) in northern Chile

    NASA Astrophysics Data System (ADS)

    Hernáez, Patricio; Palma, Sergio; Wehrtmann, Ingo S.

    2008-12-01

    The thalassinidean shrimp Callichirus seilacheri is a common species in the intertidal zone of the South American Pacific coast. However, our knowledge of its reproductive ecology is rather limited. The present study was carried out between January and December 2003 at Las Machas, northern Chile. Although ovigerous females were encountered almost throughout the study period, they were particularly abundant between May and September when water temperatures were lowest and sediment coverage of the burrow entrances was highest. Females of C. seilacheri produced numerous (17,450 ± 3,796 eggs) and small (0.884 ± 0.080 mm; 0.262 ± 0.054 mm3) eggs when compared to other thalassinidean shrimps for which such information is available. Fecundity was positively correlated with female size; however, correlations were allometric, which might be related to the elasticity of the abdomen. Egg volume increased by 41.2% during embryogenesis, and egg loss during the incubation period was on average 8%. Females inverted on average 14.9% of their dry weight into egg production.

  6. Enzyme activity in the aestivating green-striped burrowing frog (Cyclorana alboguttata).

    PubMed

    Mantle, Beth L; Guderley, Helga; Hudson, Nicholas J; Franklin, Craig E

    2010-10-01

    Green-striped burrowing frogs (Cyclorana alboguttata) can depress their resting metabolism by more than 80% during aestivation. Previous studies have shown that this species is able to withstand long periods of immobilisation during aestivation while apparently maintaining whole muscle mass and contractile performance. The aim of this study was to determine the effect of prolonged aestivation on the levels of metabolic enzymes (CCO, LDH and CS) in functionally distinct skeletal muscles (cruralis, gastrocnemius, sartorius, iliofibularis and rectus abdominus) and liver of C. alboguttata. CS activity was significantly reduced in all tissues except for the cruralis, gastrocnemius and the liver. LDH activity was significantly reduced in the sartorius and rectus abdominus, but remained at control (active) levels in the other tissues. CCO activity was significantly reduced in the gastrocnemius and rectus abdominus, and unchanged in the remaining tissues. Muscle protein was significantly reduced in the sartorius and iliofibularis during aestivation, and unchanged in the remaining muscles. The results suggest that the energy pathways involved in the production and consumption of ATP are remodelled during prolonged aestivation but selective. Remodelling and subsequent down-regulation of metabolic activity seem to target the smaller non-jumping muscles, while the jumping muscles retain enzyme activities at control levels during aestivation. These results suggest a mechanism by which aestivating C. alboguttata are able to maintain metabolic depression while ensuring that the functional capacity of critical muscles is not compromised upon emergence from aestivation. PMID:20364343

  7. 10 CFR 5.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Recruitment. 5.510 Section 5.510 Energy NUCLEAR REGULATORY... Prohibited § 5.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been...

  8. 24 CFR 3.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Recruitment. 3.310 Section 3.310... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 3.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 3.300 through 3.310 apply shall not discriminate on the...

  9. 45 CFR 618.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Recruitment. 618.310 Section 618.310 Public... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 618.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 618.300 through 618.310 apply shall not discriminate on...

  10. 44 CFR 19.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Recruitment. 19.510 Section... Programs or Activities Prohibited § 19.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where...

  11. 44 CFR 19.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Recruitment. 19.310 Section... RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 19.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 19.300 through...

  12. 31 CFR 28.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Recruitment. 28.310 Section 28.310... Basis of Sex in Admission and Recruitment Prohibited § 28.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 28.300 through 28.310 apply shall not discriminate on the basis of sex...

  13. 34 CFR 106.23 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Recruitment. 106.23 Section 106.23 Education... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 106.23 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which this subpart applies shall not discriminate on the basis of...

  14. 20 CFR 655.156 - Recruitment report.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Recruitment report. 655.156 Section 655.156... the United States (H-2A Workers) Post-Acceptance Requirements § 655.156 Recruitment report. (a) Requirements of a recruitment report. The employer must prepare, sign, and date a written recruitment...

  15. 10 CFR 1042.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Recruitment. 1042.510 Section 1042.510 Energy DEPARTMENT... Education Programs or Activities Prohibited § 1042.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of...

  16. 20 CFR 656.21 - Supervised recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Supervised recruitment. 656.21 Section 656.21... Supervised recruitment. (a) Supervised recruitment. Where the Certifying Officer determines it appropriate, post-filing supervised recruitment may be required of the employer for the pending application...

  17. 45 CFR 618.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Recruitment. 618.510 Section 618.510 Public... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  18. 38 CFR 23.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Recruitment. 23.310... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 23.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 23.300 through 23.310 apply shall not discriminate on...

  19. 22 CFR 146.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Recruitment. 146.510 Section 146.510 Foreign... Education Programs or Activities Prohibited § 146.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of...

  20. 34 CFR 106.53 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Recruitment. 106.53 Section 106.53 Education... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  1. 45 CFR 2555.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Recruitment. 2555.510 Section 2555.510 Public... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  2. 36 CFR 1211.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Recruitment. 1211.310 Section... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1211.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 1211.300 through 1211.310 apply shall not discriminate on...

  3. 32 CFR 196.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Recruitment. 196.310 Section 196.310 National... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 196.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 196.300 through 196.310 apply shall not discriminate on...

  4. 36 CFR 1211.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Recruitment. 1211.510 Section... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  5. 49 CFR 25.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Recruitment. 25.510 Section 25.510 Transportation... Education Programs or Activities Prohibited § 25.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of...

  6. 18 CFR 1317.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Recruitment. 1317.310... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 1317.300 through 1317.310 apply shall not discriminate on...

  7. 38 CFR 23.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Recruitment. 23.510... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  8. 41 CFR 101-4.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Recruitment. 101-4.510... Employment in Education Programs or Activities Prohibited § 101-4.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and...

  9. 32 CFR 196.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Recruitment. 196.510 Section 196.510 National... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  10. 13 CFR 113.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Recruitment. 113.310 Section 113... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 113.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 113.300 through 113.310 apply shall not discriminate on...

  11. 29 CFR 36.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Recruitment. 36.510 Section 36.510 Labor Office of the... Activities Prohibited § 36.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient...

  12. 29 CFR 36.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Recruitment. 36.310 Section 36.310 Labor Office of the... FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 36.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 36.300 through...

  13. 13 CFR 113.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Recruitment. 113.510 Section 113... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  14. 10 CFR 5.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Recruitment. 5.310 Section 5.310 Energy NUCLEAR REGULATORY... FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 5.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 5.300 through 5.310 apply shall...

  15. 24 CFR 3.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Recruitment. 3.510 Section 3.510... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  16. 7 CFR 15a.53 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Recruitment. 15a.53 Section 15a.53 Agriculture Office... Activities Prohibited § 15a.53 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient...

  17. 22 CFR 229.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Recruitment. 229.510 Section 229.510 Foreign... in Education Programs or Activities Prohibited § 229.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and...

  18. 45 CFR 2555.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Recruitment. 2555.310 Section 2555.310 Public... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 2555.310 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which §§ 2555.300 through 2555.310 apply shall not discriminate on...

  19. 18 CFR 1317.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Recruitment. 1317.510... Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient has been found to be...

  20. 7 CFR 15a.23 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Recruitment. 15a.23 Section 15a.23 Agriculture Office... FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 15a.23 Recruitment. (a) Nondiscriminatory recruitment. A recipient to which this subpart applies...

  1. 20 CFR 655.30 - Supervised recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Supervised recruitment. 655.30 Section 655.30... Workers) § 655.30 Supervised recruitment. (a) Supervised recruitment. Where an employer is found to have... failed to adequately conduct recruitment activities or failed in any obligation of this part, the CO...

  2. Recruiting Trends, 2009-2010

    ERIC Educational Resources Information Center

    Collegiate Employment Research Institute (NJ3), 2010

    2010-01-01

    This paper presents the recruiting trends for 2009-2010. This year's report is based on over 2,500 respondents, of which approximately 2,259 provided useable information with 1,846 including complete hiring figures used for the projections. The researchers continued their focus on fast-growth companies and expanded their efforts to ensure a…

  3. JCC Recruitment, Retention, Attrition Project.

    ERIC Educational Resources Information Center

    Horvath, Ronald J.

    In an effort to reduce the class attrition rate of 40% at Jefferson Community College (JCC), and to investigate the entire process of recruitment, retention, and attrition (RRA), a series of four faculty workshops were held. The plan was to look at the RRA process from the student's point of view in terms of four phases: (1) the pre-enrollment…

  4. Building a Winning Recruiting Team.

    ERIC Educational Resources Information Center

    Taguchi, Sherrie Gong

    2002-01-01

    Building a winning recruiting team is essential to the well being of virtually every organization. Putting together a great mix of people to represent an organization and bring in new talent can serve an organization well when competition is fierce or demand is down. (GCP)

  5. Recruiting Trends, 2005-2006

    ERIC Educational Resources Information Center

    Collegiate Employment Research Institute (NJ3), 2006

    2006-01-01

    Almost 900 employers responded to this year's "Recruiting Trends" survey, the largest response in the history of this project. Hiring of college graduates is expected to increase by single digits minimally, or double digits if certain geographic sectors are excluded (between 6% and 14%). This growth follows a robust 20% increase in hiring reported…

  6. Recruiting and Retaining Summer Staff.

    ERIC Educational Resources Information Center

    Crossen, Brian; Yerkes, Rita

    1998-01-01

    Recruiting of camp staff is challenged by economic and workplace restructuring, including business downsizing, part-time and temporary employment patterns, and generational attitude changes. Strategies for hiring and retaining staff include knowing what college-age workers want, marketing benefits, adopting new business strategies, and empowering…

  7. Recruiting Trends, 2008-2009

    ERIC Educational Resources Information Center

    Collegiate Employment Research Institute (NJ3), 2009

    2009-01-01

    This paper presents the recruiting trends for 2008-2009. This year's report is based on 945 respondents, including 57 K-12 schools. The researchers continued their focus on fast-growth small companies and expended most of their energy in retaining their sample distribution, knowing that the prevailing economic situation would reduce responses.…

  8. Recruiting Trends, 2007-2008

    ERIC Educational Resources Information Center

    Collegiate Employment Research Institute (NJ3), 2008

    2008-01-01

    This paper presents the recruiting trends for 2007-2008. This year's report is based on 994 respondents, including 84 K-12 school districts. The researchers focused attention on growing companies, based on lists from Forbes and Inc. magazines, and as a result, they have more small and medium-size employers represented this year. The sample…

  9. Recruiting physicians without inviting trouble.

    PubMed

    Hoch, L J

    1989-05-01

    Many hospitals use physician recruitment strategies--generally assistance or employment strategies--to ensure medical staff loyalty. Although these strategies appeal to both hospitals and physicians, they are becoming increasingly problematic. Over the past three years, the government has issued pronouncements that question their legality. Thus any hospital considering physician recruitment strategies would be wise to evaluate them in light of various legal issues. such as reimbursement, nonprofit taxation, corporate practice of medicine, and certificate-of-need statutes. The consequences of failing to consider these issues can be ominous. The penalties for violating the proscribed remuneration provision of the Medicare act can include a fine, imprisonment, suspension from the Medicare and Medicaid programs, or loss of license. Payment issues can result in reduced reimbursement levels. Nonprofit taxation issues can trigger the loss of tax exemption. As a result of the corporate practice of medicine, a physician recruitment strategy may not be reimbursable by third-party payers or may even constitute the unauthorized practice of medicine. Finally, in some states, physician recruitment may trigger certificate-of-need review. PMID:10303456

  10. A Blueprint for Student Recruitment

    ERIC Educational Resources Information Center

    Chamberlain, Frank M.

    1977-01-01

    A marketing plan from the Young Presidents' Organization Task Force is offered: define the market; identify the target student; clarify the college selection process; assess the competition; define the college in terms of market needs; develop a recruiting strategy; develop objectives for the year; spell out the tactics; and manage for results.…

  11. Recruiting Trends, 2006-2007

    ERIC Educational Resources Information Center

    Collegiate Employment Research Institute (NJ3), 2007

    2007-01-01

    College students who plan on entering the labor market can expect to see more job opportunities in the spring of 2007, according to information supplied by 864 companies and organizations to this year's Recruiting Trends Report. After two years of double digit growth, the expansion will slow to a modest 4% to 6%. Two opposing factors appear to be…

  12. Recruiting Strategies for Women's Colleges.

    ERIC Educational Resources Information Center

    Ricci, Ronald J.

    1994-01-01

    Methods for combating declining applicant pools at women's colleges are discussed. Research suggests that effective student recruitment can be facilitated by the use of single-gender market niche as a means for differentiation and parent influence for promotion. Review of strategies currently used indicate these marketing methods are underused and…

  13. Recruiting and Retaining Adult Students.

    ERIC Educational Resources Information Center

    Hadfield, Janice

    2003-01-01

    Adult learners, long the stepchildren of colleges and universities, have nearly become the norm, and they spend billions of dollars each year on education. This chapter takes a customer-oriented approach to recruiting and retaining adult students in higher education. (GCP)

  14. Intracellular signalling during neutrophil recruitment.

    PubMed

    Mócsai, Attila; Walzog, Barbara; Lowell, Clifford A

    2015-08-01

    Recruitment of leucocytes such as neutrophils to the extravascular space is a critical step of the inflammation process and plays a major role in the development of various diseases including several cardiovascular diseases. Neutrophils themselves play a very active role in that process by sensing their environment and responding to the extracellular cues by adhesion and de-adhesion, cellular shape changes, chemotactic migration, and other effector functions of cell activation. Those responses are co-ordinated by a number of cell surface receptors and their complex intracellular signal transduction pathways. Here, we review neutrophil signal transduction processes critical for recruitment to the site of inflammation. The two key requirements for neutrophil recruitment are the establishment of appropriate chemoattractant gradients and the intrinsic ability of the cells to migrate along those gradients. We will first discuss signalling steps required for sensing extracellular chemoattractants such as chemokines and lipid mediators and the processes (e.g. PI3-kinase pathways) leading to the translation of extracellular chemoattractant gradients to polarized cellular responses. We will then discuss signal transduction by leucocyte adhesion receptors (e.g. tyrosine kinase pathways) which are critical for adhesion to, and migration through the vessel wall. Finally, additional neutrophil signalling pathways with an indirect effect on the neutrophil recruitment process, e.g. through modulation of the inflammatory environment, will be discussed. Mechanistic understanding of these pathways provide better understanding of the inflammation process and may point to novel therapeutic strategies for controlling excessive inflammation during infection or tissue damage. PMID:25998986

  15. Recruitment dynamics in adaptive social networks.

    PubMed

    Shkarayev, Maxim S; Schwartz, Ira B; Shaw, Leah B

    2013-01-01

    We model recruitment in adaptive social networks in the presence of birth and death processes. Recruitment is characterized by nodes changing their status to that of the recruiting class as a result of contact with recruiting nodes. Only a susceptible subset of nodes can be recruited. The recruiting individuals may adapt their connections in order to improve recruitment capabilities, thus changing the network structure adaptively. We derive a mean field theory to predict the dependence of the growth threshold of the recruiting class on the adaptation parameter. Furthermore, we investigate the effect of adaptation on the recruitment level, as well as on network topology. The theoretical predictions are compared with direct simulations of the full system. We identify two parameter regimes with qualitatively different bifurcation diagrams depending on whether nodes become susceptible frequently (multiple times in their lifetime) or rarely (much less than once per lifetime). PMID:25395989

  16. Distribution and abundance of burrowing mayflies (Hexagenia spp.) in Lake Erie, 1997-2005

    USGS Publications Warehouse

    Krieger, K.A.; Bur, M.T.; Ciborowski, J.J.H.; Barton, D.R.; Schloesser, D.W.

    2007-01-01

    Burrowing mayflies (Hexagenia limbata and H. rigida) recolonized sediments of the western basin of Lake Erie in the 1990s following decades of pollution abatement. We predicted that Hexageniawould also disperse eastward or expand from existing localized populations and colonize large regions of the other basins. We sampled zoobenthos in parts of the western and central basins yearly from 1997–2005, along the north shore of the eastern basin in 2001–2002, and throughout the lake in 2004. In the island area of the western basin, Hexagenia was present at densities ≤1,278 nymphs/m2and exhibited higher densities in odd years than even years. By contrast, Hexagenia became more widespread in the central basin from 1997–2000 at densities ≤48 nymphs/m2 but was mostly absent from 2001–2005. Nymphs were found along an eastern basin transect at densities ≤382/m2 in 2001 and 2002. During the 2004 lake-wide survey, Hexagenia was found at 63 of 89 stations situated throughout the western basin (≤1,636 nymphs/m2, mean = 195 nymphs/m2, SE = 32, N = 89) but at only 7 of 112 central basin stations, all near the western edge of the basin (≤708 nymphs/m2), and was not found in the eastern basin. Hexagenia was found at 2 of 62 stations (≤91 nymphs/m2) in harbors, marinas, and tributaries along the south shore of the central basin in 2005. Oxygen depletion at the sediment-water interface and cool temperatures in the hypolimnion are probably the primary factors preventing successful establishment throughout much of the central basin. Hexagenia can be a useful indicator of lake quality where its distribution and abundance are limited by anthropogenic causes.

  17. Phylogenetic relationships of Darwin's "Mr. Arthrobalanus": The burrowing barnacles (Cirripedia: Acrothoracica).

    PubMed

    Lin, Hsiu-Chin; Kobasov, Gregory A; Chan, Benny K K

    2016-07-01

    The barnacles of the superorder Acrothoracica are small, burrowing, epibiotic, and dioecious (large female with dwarf male) crustaceans largely found in the carbonate sediments and skeletons of marine invertebrates. The acrothoracicans represent the Cirripedia with the most plesiomorphic characters and have prominently featured in phylogenetic speculations concerning these crustaceans. Traditionally, Acrothoracica was divided into two main orders, Pygophora and Apygophora. The Apygophora had uniramus cirri and no anus. The Pygophora had biramus terminal cirri and an anus and was further divided into two families, Lithoglyptidae and Cryptophialidae. Kolbasov (2009) revised the superorder Acrothoracica on the basis of morphological examinations of females, dwarf males, and cyprids and rearranged the acrothoracican species into two new orders, Lithoglyptida and Cryptophialida. The present study is the first attempt to reconstruct the phylogenetic relationships of acrothoracican barnacles by sequencing two mitochondrial (cytochrome C oxidase I and 16S ribosomal DNA) and two nuclear (18S ribosomal DNA and histone H3) markers of 8 of the 11 genera comprising 23 acrothoracican species. All monophylies of the eight acrothoracican genera sampled in this study were strongly supported. The deep interfamilial relationship constructed is consistent with the recent morphological phylogenetic relationship proposed by Kolbasov, Newman, and Høeg (Kolbasov, 2009) that Cryptophialidae (order Cryptophialida) is the sister group to all other acrothoracicans (order Lithoglyptida). According to an ancestral character state reconstruction analysis, the posterior lobes of females; armament of opercular bars, attachment stalk, lateral projections of the body, and aperture slits in dwarf males; and habitat use appear to have phylogenetic importance. PMID:26988415

  18. Burrowing mayflies as indicators of ecosystem health: status of populations in two western Lake Superior embayments

    USGS Publications Warehouse

    Edsall, Thomas A.; Gorman, Owen T.; Evrard, Lori M.

    2004-01-01

    The U.S. Environmental Protection Agency and Environment Canada are supporting the development of indicators of ecosystem health that can be used to report on progress in restoring and maintaining the Great Lakes ecosystem, as called for in the Great Lakes Water Quality Agreement between the United States and Canada. One indicator under development for Great Lakes mesotrophic environments is based on burrowing mayflies ( Hexagenia: Ephemeroptera: Ephemeridae). In this paper, we report the results of a benthic survey in spring 2002 to determine the status of nymphal populations of Hexagenia in two western Lake Superior embayments, the St. Louis River estuary, an area with significant water-use impairments, and Chequamegon Bay, an area with no known water-use impairments. Ponar grab samples collected throughout these embayments showed nymphs were generally abundant in finely particulate, cohesive substrate (clay or mixtures of clay and sand) in both embayments. However, in the St. Louis River estuary nymphs were absent in those preferred substrates at 11 stations in the eastern portion of St. Louis Bay and the adjoining northwestern portion of the Duluth-Superior Harbor, where the sediments were variously contaminated with visible amounts of taconite pellets, paint chips, oil, or combusted coal waste (clinkers). Our results suggest that human activities have rendered those portions of the St. Louis River estuary unsuitable for habitation by Hexagenia nymphs and we recommend that trend monitoring of the nymphal population there be conducted to permit reporting on progress in restoring and maintaining the health and integrity of this Great Lakes ecosystem embayment, consistent with the intent of the Great Lakes Water Quality Agreement.

  19. Conditions for the return and simulation of the recovery of burrowing mayflies in western Lake Erie

    USGS Publications Warehouse

    Kolar, Cynthia S.; Hudson, Patrick L.; Savino, Jacqueline F.

    1997-01-01

    In the 1950s, burrowing mayflies, Hexagenia spp. (H. Limbata and H. Rigida), were virtually eliminated from the western basin of Lake Erie (a 3300 kmA? area) because of eutrophication and pollution. We develop and present a deterministic model for the recolonization of the western basin by Hexagenia to pre-1953 densities. The model was based on the logistic equation describing the population growth of Hexagenia and a presumed competitor, Chironomus (dipteran larvae). Other parameters (immigration, low oxygen, toxic sediments, competition with Chironomus, and fish predation) were then individually added to the logistic model to determine their effect at different growth rates. The logistic model alone predicts 10-41 yr for Hexagenia to recolonize western Lake Erie. Immigration reduced the recolonization time by 2-17 yr. One low-oxygen event during the first 20 yr increased recovery time by 5-17 yr. Contaminated sediments added 5-11 yr to the recolonization time. Competition with Chironomus added 8-19 yr to recovery. Fish predators added 4-47 yr to the time required for recolonization. The full model predicted 48-81 yr for Hexagenia to reach a carrying capacity of approximately 350 nymphs/mA?, or not until around the year 2038 if the model is started in 1990. The model was verified by changing model parameters to those present in 1970, beginning the model in 1970 and running it through 1990. Predicted densities overlapped almost completely with actual estimated densities of Hexagenia nymphs present in the western basin in Lake Erie in 1990. The model suggests that recovery of large aquatic ecosystems may lag substantially behind remediation efforts.

  20. Patterns of Saccharina latissima Recruitment

    PubMed Central

    Andersen, Guri Sogn

    2013-01-01

    The lack of recovery in Norwegian populations of the kelp Saccharina latissima (Linnaeus) C. E. Lane, C. Mayes, Druehl & G. W. Saunders after a large-scale disturbance that occurred sometime between the late 1990s and early 2000s has raised considerable concerns. Kelp forests are areas of high production that serve as habitats for numerous species, and their continued absence may represent the loss of an entire ecosystem. Some S. latissima populations remain as scattered patches within the affected areas, but today, most of the areas are completely devoid of kelp. The question is if natural recolonization by kelp and the reestablishment of the associated ecosystem is possible. Previous studies indicate that a high degree of reproductive synchrony in macrophytes has a positive effect on their potential for dispersal and on the connectivity between populations, but little is known about the patterns of recruitment in Norwegian S. latissima. More is, however, known about the development of fertile tissue (sori) on adult individuals, which is easily observed. The present study investigated the degree of coupling between the appearance of sori and the recruitment on clean artificial substrate beneath adult specimens. The pattern of recruitment was linked to the retreat of visible sori (i.e. spore release) and a seasonal component unrelated to the fertility of the adults. The formation and the retreat of visible sori are processes that seem synchronized along the south coast of Norway, and the link between sori development and recruitment may therefore suggest that the potential for S. latissima dispersal is relatively large. These results support the notion that the production and dispersal of viable spores is unlikely to be the bottleneck preventing recolonization in the south of Norway, but studies over larger temporal and spatial scales are still needed to confirm this hypothesis. PMID:24349034

  1. Recruiting from within: Action-Oriented Research Solutions to Internal Student Recruitment in Collegiate Aviation Education.

    ERIC Educational Resources Information Center

    Bowen, Brent; Carstenson, Larry; Hansen, Frederick

    1999-01-01

    Discusses student recruitment in aviation education and establishes that internal recruitment methods are the most productive and cost effective. Provides examples of recruitment strategies based on a model of action research. (JOW)

  2. International Nurse Recruitment in India

    PubMed Central

    Khadria, Binod

    2007-01-01

    Objective This paper describes the practice of international recruitment of Indian nurses in the model of a “business process outsourcing” of comprehensive training-cum-recruitment-cum-placement for popular destinations like the United Kingdom and United States through an agency system that has acquired growing intensity in India. Findings Despite the extremely low nurse to population ratio in India, hospital managers in India are not concerned about the growing exodus of nurses to other countries. In fact, they are actively joining forces with profitable commercial ventures that operate as both training and recruiting agencies. Most of this activity is concentrated in Delhi, Bangalore, and Kochi. Conclusions Gaps in data on nursing education, employment, and migration, as well as nonstandardization of definitions of “registered nurse,” impair the analysis of international migration of nurses from India, making it difficult to assess the impact of migration on vacancy rates. One thing is clear, however, the chain of commercial interests that facilitate nurse migration is increasingly well organized and profitable, making the future growth of this business a certainty. PMID:17489924

  3. Ventilatory and metabolic responses of burrowing owls, Athene cunicularia, to moderate and extreme hypoxia: analysis of the hypoxic ventilatory threshold vs. hemoglobin oxygen affinity relationship in birds.

    PubMed

    Kilgore, Delbert L; Boggs, Dona F; Kilgore, Trevor J; Colby, Conrad; Williams, Burl R; Bavis, Ryan W

    2008-06-01

    We measured ventilation, oxygen consumption and blood gases in burrowing owls (Athene cunicularia) breathing moderate and extreme hypoxic gas mixtures to determine their hypoxic ventilatory threshold (HVT) and to assess if they, like other birds and mammals, exhibit a relationship between HVT and hemoglobin O2 affinity (P(50)) of their blood. An earlier report of an attenuated ventilatory responsiveness of this species to hypoxia was enigmatic given the low O2 affinity (high P(50)) of burrowing owl hemoglobin. In the current study, burrowing owls breathing 11% and 9% O2 showed a significantly elevated total ventilation. The arterial partial pressure of oxygen (PaO2) at which ventilation is elevated above normoxic values in burrowing owls was 58 mm Hg. This threshold value conforms well to expectations based on the high P(50) of their hemoglobin and the HVT vs. P(50) relationship for birds developed in this study. Correcting for phylogenetic relatedness in the multi-species analysis had no effect on the HVT vs. P(50) relationship. Also, because burrowing owls in this study did not show a hypometabolic response at any level of hypoxia (even at 9% O2); HVT described in terms of percent change in oxygen convection requirement is identical to that based on ventilation alone. PMID:17561426

  4. Ontogenetic allometry constrains cranial shape of the head-first burrowing worm lizard Cynisca leucura (Squamata: Amphisbaenidae).

    PubMed

    Hipsley, Christy A; Rentinck, Marc-Nicolas; Rödel, Mark-Oliver; Müller, Johannes

    2016-09-01

    Amphisbaenians are fossorial, predominantly limbless squamate reptiles with distinct cranial shapes corresponding to specific burrowing behaviors. Due to their cryptic lifestyles and the scarcity of museum specimens, little is known of their intraspecific variation, particularly regarding cranial osteology. This represents a critical lack of information, because the majority of morphological investigations of squamate relationships are based on cranial characters. We investigated cranial variation in the West African Coast Worm Lizard Cynisca leucura, a round-headed member of the Amphisbaenidae. Using geometric morphometric analyses of three-dimensional computed tomographic scans, we found that cranial osteology of C. leucura is highly conserved, with the majority of shape changes occurring during growth as the cranium becomes more slender and elongate, accompanied by increasing interdigitation among the dermal roofing bones. Elements of the ventral portion of the cranium remain loosely connected in adults, possibly as a protective mechanism against repeated compression and torsion during burrow excavation. Intraspecific variation was strongly correlated with size change from juveniles to adults, indicating a dominant role of ontogenetic allometry in determining cranial shape. We found no evidence of sexual dimorphism, either during growth or among adults. Given the fossorial habits of C. leucura, we hypothesize that cranial allometry is under strong stabilizing selection to maintain adequate proportions for head-first digging, thereby constraining the ability of individuals to respond to differing selection pressures, including sexual selection and variation in diet or microhabitat. For species in which digging imposes less mechanical stress (e.g., in softer sand), allometric associations during growth may be weakened, allowing changes to the ontogenetic trajectory and subsequent morphological traits. Such developmental dissociation between size and shape, known

  5. Imidacloprid residues in Willapa Bay (Washington State) water and sediment following application for control of burrowing shrimp.

    PubMed

    Felsot, Allan S; Ruppert, Judy R

    2002-07-17

    Pesticides have been used in the Willapa Bay estuary in western Washington State to control the exotic invasive plant species Spartina alterniflora (cordgrass) and the native species of burrowing shrimp (Callianassa sp.; Upogebia sp.) that affect oyster production. Carbaryl, the only registered insecticide for control of burrowing shrimp, has not been extensively studied in the Willapa Bay. However, carbaryl use has been severely restricted, and alternatives likely to have less severe environmental impacts are being sought. Imidacloprid applied directly to exposed sediments when the tide is out is efficacious for burrowing shrimp control but lacks studies of its behavior in the estuary. For this study, imidacloprid dissipation was monitored as the tide was rising in Willapa Bay. Over 99% of applied material dissipated from small plots within 24 h, but residues near the analytical detection limit were found in sediments 28 days later. At a distance of 152 m along a transect from the plot in the direction of tidal flow, imidacloprid residues in water peaked within 10 min after initiation of tidal flow. Within 30 min, imidacloprid residues were not detected, nor were residues detected in the water any time over the next month after application. Carbaryl residues in water were also monitored, and they exhibited the same rise and fall at the 152 m distance from the experimental plot as did the imidacloprid residues. However, carbaryl levels significantly above the detection limit were still present in water over the next month after application. The rapid dissipation of imidacloprid from water was hypothesized to be due to extensive dilution by the tide. The hypothesis was tested in batch equilibration sorption studies with radiolabeled imidacloprid and Willapa Bay sediment. Sorption distribution coefficients were <1 mL/g, and hysteresis was not observed during two desorption cycles, suggesting that imidacloprid was widely dispersed to extremely low levels soon after

  6. Comparison of hydraulics and particle removal efficiencies in a mixed cell raceway and Burrows pond rearing system

    USGS Publications Warehouse

    Moffitt, Christine M.

    2016-01-01

    We compared the hydrodynamics of replicate experimental mixed cell and replicate standard Burrows pond rearing systems at the Dworshak National Fish Hatchery, ID, in an effort to identify methods for improved solids removal. We measured and compared the hydraulic residence time, particle removal efficiency, and measures of velocity using several tools. Computational fluid dynamics was used first to characterize hydraulics in the proposed retrofit that included removal of the traditional Burrows pond dividing wall and establishment of four counter rotating cells with appropriate drains and inlet water jets. Hydraulic residence time was subsequently established in the four full scale test tanks using measures of conductivity of a salt tracer introduced into the systems both with and without fish present. Vertical and horizontal velocities were also measured with acoustic Doppler velocimetry in transects across each of the rearing systems. Finally, we introduced ABS sinking beads that simulated fish solids then followed the kinetics of their removal via the drains to establish relative purge rates. The mixed cell raceway provided higher mean velocities and a more uniform velocity distribution than did the Burrows pond. Vectors revealed well-defined, counter-rotating cells in the mixed cell raceway, and were likely contributing factors in achieving a relatively high particle removal efficiency-88.6% versus 8.0% during the test period. We speculate retrofits of rearing ponds to mixed cell systems will improve both the rearing environments for the fish and solids removal, improving the efficiency and bio-security of fish culture. We recommend further testing in hatchery production trials to evaluate fish physiology and growth.

  7. Denitrification and Nitrogen Fixation Dynamics in the Area Surrounding an Individual Ghost Shrimp (Neotrypaea californiensis) Burrow System

    PubMed Central

    Bertics, Victoria J.; Sohm, Jill A.; Magnabosco, Cara

    2012-01-01

    Bioturbated sediments are thought of as areas of increased denitrification or fixed-nitrogen (N) loss; however, recent studies have suggested that not all N may be lost from these environments, with some N returning to the system via microbial dinitrogen (N2) fixation. We investigated denitrification and N2 fixation in an intertidal lagoon (Catalina Harbor, CA), an environment characterized by bioturbation by thalassinidean shrimp (Neotrypaea californiensis). Field studies were combined with detailed measurements of denitrification and N2 fixation surrounding a single ghost shrimp burrow system in a narrow aquarium (15 cm by 20 cm by 5 cm). Simultaneous measurements of both activities were performed on samples taken within a 1.5-cm grid for a two-dimensional illustration of their intensity and distribution. These findings were then compared with rate measurements performed on bulk environmental sediment samples collected from the lagoon. Results for the aquarium indicated that both denitrification and N2 fixation have a patchy distribution surrounding the burrow, with no clear correlation to each other, sediment depth, or distance from the burrow. Field denitrification rates were, on average, lower in a bioturbated region than in a seemingly nonbioturbated region; however, replicates showed very high variability. A comparison of denitrification field results with previously reported N2 fixation rates from the same lagoon showed that in the nonbioturbated region, depth-integrated (10 cm) denitrification rates were higher than integrated N2 fixation rates (∼9 to 50 times). In contrast, in the bioturbated sediments, depending on the year and bioturbation intensity, some (∼6.2%) to all of the N lost via denitrification might be accounted for via N2 fixation. PMID:22447588

  8. The chemistry and mineralogy of haloed burrows in pelagic sediment at DOMES Site A: The equatorial North Pacific

    USGS Publications Warehouse

    Piper, D.Z.; Rude, P.D.; Monteith, S.

    1987-01-01

    The chemical and mineralogical composition of burrowed sediment, recovered in 66 box cores at latitude 9??25???N and longitude 151??15???W in the equatorial Pacific, demonstrates the important role of infauna in determining the geochemistry of pelagic sediment. Haloed burrows, approximately 3 cm across, were present in many of the cores. Within early Tertiary sediment that was covered by less than 5 cm of surface Quaternary sediment in several cores, the burrows in cross-section consist of three units: (1) a dark yellowish-brown central zone of Quaternary sediment surrounded, by (2) a pale yellowish-orange zone (the halo) of Tertiary sediment, which is surrounded by (3) a metal-oxide precipitate; the enclosing Tertiary sediment is dusky brown. Several elements - Mn, Ni, Cu, Co, Zn, Sb and Ce - have been leached from the light-colored halo, whereas Cr, Cs, Hf, Rb, Sc, Ta, Th, U, the rare earth elements exclusive of Ce, and the major oxides have not been leached. The metal-oxide zone, 1-5 mm thick, contains as much as 16% MnO2, as the mineral todorokite. The composition of the todorokite, exclusive of the admixed Tertiary sediment, resembles the composition of the metal deficit of the halo and also the composition of surface ferromanganese nodules that have been interpreted as having a predominantly diagenetic origin. Thus bioturbation contributes not only to the redistribution of metals within pelagic sediment, but also to the accretion of ferromanganese nodules on the sea floor. ?? 1987.

  9. Hatching asynchrony in Burrowing Owls is influenced by clutch size and hatching success but not by food.

    PubMed

    Wellicome, Troy I

    2005-01-01

    In most animals, siblings from a given reproductive event emerge over a very short period of time. In contrast, many species of birds hatch their young asynchronously over a period of days or weeks, handicapping last-hatched chicks with an age and size disadvantage. Numerous studies have examined the adaptive significance of this atypical hatching pattern, but few have attempted to explain the considerable intrapopulation variation that exists in hatching asynchrony. I explored proximate determinants of hatching asynchrony by monitoring 112 Burrowing Owl (Athene cunicularia) nests in the grasslands of southern Saskatchewan, Canada, over 4 years. Age disparities between first- and last-hatched siblings (i.e., hatching spans) varied considerably, ranging between 1 and 7 days (mode = 4 days). These hatching spans increased with increased hatching success. Hatching spans also increased with larger clutches, but the increase was less than predicted given the increased time required to lay more eggs. Hatching span was unrelated to number of prey cached in the nest during egg laying (an index of food availability), and was unaltered by a year of super-abundant prey. Furthermore, pairs given extra food during laying had hatching spans equal to those of unsupplemented control pairs. These results were inconsistent with both the energy constraint and facultative manipulation hypotheses, which predict that hatching asynchrony should vary with the level of food during laying, when incubation onset is determined. Burrowing Owls were apparently free of food limitation early in breeding, yet may not have been able to optimize hatching spans because food conditions during laying were largely unrelated to food conditions during brooding. Thus, one of the premises for facultative manipulation of hatching asynchrony-that laying females are able to forecast post-hatch food conditions-may not have been met for this population of Burrowing Owls. PMID:15480800

  10. Recruiting and retaining indigenous farmworker participants.

    PubMed

    Farquhar, Stephanie; de Jesus Gonzalez, Carmen; Hall, Jennifer; Samples, Julie; Ventura, Santiago; Sanchez, Valentin; Shadbeh, Nargess

    2014-10-01

    There is limited information on the specific practices used to successfully recruit and retain indigenous and Latino farmworkers in research studies. This article describes the strategies used in a community-based participatory research project with indigenous agricultural workers. Participants were recruited through consulting with indigenous relatives and friends, identifying and meeting with indigenous leaders from hometown associations in countries of origin, and asking current participants to recruit fellow farmworkers. Adjustments were initiated to the second year protocol to enhance recruitment and retention. The difference in attrition rates between years one and two was statistically significant, a difference partially attributed to modifications to recruitment and retention protocol. Findings confirmed that active recruitment techniques and word-of-mouth recruitment were more effective than passive methods. Trust among academic, organization, and community partners, and shared language and culture between those doing the recruitment and the participants, contributed to sustained farmworker participation. PMID:23733354

  11. Recruiting and retaining indigenous farmworker participants

    PubMed Central

    Farquhar, Stephanie; de Jesus Gonzalez, Carmen; Hall, Jennifer; Samples, Julie; Ventura, Santiago; Sanchez, Valentin; Shadbeh, Nargess

    2013-01-01

    There is limited information on the specific practices used to successfully recruit and retain indigenous and Latino farmworkers in research studies. This article describes the strategies used in a community-based participatory research project with indigenous agricultural workers. Participants were recruited through consulting with indigenous relatives and friends, identifying and meeting with indigenous leaders from hometown associations in countries of origin, and asking current participants to recruit fellow farmworkers. Adjustments were initiated to the second year protocol to enhance recruitment and retention. The difference in attrition rates between years one and two was statistically significant, a difference partially attributed to modifications to recruitment and retention protocol. Findings confirmed that active recruitment techniques and word-of-mouth recruitment were more effective than passive methods. Trust among academic, organization, and community partners, and shared language and culture between those doing the recruitment and the participants, contributed to sustained farmworker participation. PMID:23733354

  12. Difficulties in the Recruitment of Black Students

    ERIC Educational Resources Information Center

    Carnes, G. D.

    1972-01-01

    Attempts to recruit black students for a rehabilitation-education program are described. Following a discussion of the problems encountered, the author proposes guidelines for the recruitment and retention of black students. (Author)

  13. Proposed Recruit Training Topic: Rape Awareness.

    ERIC Educational Resources Information Center

    Thompson, Janet R.

    This guide, prepared by the United States Navy Recruit Training Command, was designed to address the differential training needs of male and female recruits in the area of personal security, i.e., rape awareness/prevention. In section I, the role of the Recruit Training Command is noted, and information on the incidence of sexual assault is…

  14. Recruitment and Strategies for Small Schools.

    ERIC Educational Resources Information Center

    Seifert, Edward H.

    The guide is designed to assist the small school administrator in the successful recruitment of teachers. It provides a recruitment design, which encompasses community and school assets, and a list of "ideal characteristics" of teachers who are congruent with the needs of small schools. Fifteen strategies for effective recruitment include…

  15. 18 CFR 1317.310 - Recruitment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Recruitment. 1317.310... THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.310 Recruitment....

  16. 18 CFR 1317.310 - Recruitment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Recruitment. 1317.310... THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.310 Recruitment....

  17. 18 CFR 1317.310 - Recruitment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Recruitment. 1317.310... THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.310 Recruitment....

  18. 18 CFR 1317.310 - Recruitment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Recruitment. 1317.310... THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.310 Recruitment....

  19. 20 CFR 655.205 - Recruitment period.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Recruitment period. 655.205 Section 655.205... Agricultural Employment § 655.205 Recruitment period. (a) If the OFLC Administrator determines that the... carry out the assurances contained in § 655.203 with respect to the recruitment of U.S. workers....

  20. 45 CFR 86.53 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Recruitment. 86.53 Section 86.53 Public Welfare... in Employment in Education Programs or Activities Prohibited § 86.53 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  1. Corporate Recruiters Survey: 2014 Survey Report

    ERIC Educational Resources Information Center

    Estrada Worthington, Rebecca

    2014-01-01

    The 2014 Corporate Recruiters Survey Report examines the current hiring outlook for graduate business students and analyzes demand by industry and world region, salaries, job functions, and mobility in regional job placement. It also explores recruiter behavior, including recruitment practices and school and candidate selection criteria, and…

  2. 28 CFR 345.31 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Recruitment. 345.31 Section 345.31 Judicial Administration FEDERAL PRISON INDUSTRIES, INC., DEPARTMENT OF JUSTICE FEDERAL PRISON INDUSTRIES (FPI) INMATE WORK PROGRAMS Recruitment and Hiring Practices § 345.31 Recruitment. Inmate workers...

  3. 15 CFR 8a.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Recruitment. 8a.510 Section 8a.510... in Employment in Education Programs or Activities Prohibited § 8a.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  4. 28 CFR 54.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Recruitment. 54.510 Section 54.510... in Employment in Education Programs or Activities Prohibited § 54.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  5. 6 CFR 17.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Recruitment. 17.510 Section 17.510 Domestic... in Employment in Education Programs or Activities Prohibited § 17.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  6. 14 CFR 1253.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Recruitment. 1253.510 Section 1253.510... in Employment in Education Programs or Activities Prohibited § 1253.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  7. 43 CFR 41.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Recruitment. 41.510 Section 41.510 Public... in Employment in Education Programs or Activities Prohibited § 41.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  8. 31 CFR 28.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Recruitment. 28.510 Section 28.510... Basis of Sex in Employment in Education Programs or Activities Prohibited § 28.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  9. 28 CFR 345.31 - Recruitment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Recruitment. 345.31 Section 345.31 Judicial Administration FEDERAL PRISON INDUSTRIES, INC., DEPARTMENT OF JUSTICE FEDERAL PRISON INDUSTRIES (FPI) INMATE WORK PROGRAMS Recruitment and Hiring Practices § 345.31 Recruitment. Inmate workers...

  10. 28 CFR 345.31 - Recruitment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Recruitment. 345.31 Section 345.31 Judicial Administration FEDERAL PRISON INDUSTRIES, INC., DEPARTMENT OF JUSTICE FEDERAL PRISON INDUSTRIES (FPI) INMATE WORK PROGRAMS Recruitment and Hiring Practices § 345.31 Recruitment. Inmate workers...

  11. 28 CFR 345.31 - Recruitment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Recruitment. 345.31 Section 345.31 Judicial Administration FEDERAL PRISON INDUSTRIES, INC., DEPARTMENT OF JUSTICE FEDERAL PRISON INDUSTRIES (FPI) INMATE WORK PROGRAMS Recruitment and Hiring Practices § 345.31 Recruitment. Inmate workers...

  12. 28 CFR 345.31 - Recruitment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Recruitment. 345.31 Section 345.31 Judicial Administration FEDERAL PRISON INDUSTRIES, INC., DEPARTMENT OF JUSTICE FEDERAL PRISON INDUSTRIES (FPI) INMATE WORK PROGRAMS Recruitment and Hiring Practices § 345.31 Recruitment. Inmate workers...

  13. 45 CFR 618.310 - Recruitment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 618.310 Recruitment. (a... basis of sex in the recruitment and admission of students. A recipient may be required to...

  14. Faculty Recruitment in an Era of Change

    ERIC Educational Resources Information Center

    Levine, Marilyn; Schimpf, Martin

    2010-01-01

    Faculty recruitment is a challenge for administration and departments, especially in an era of change in the academy. This article builds on information from an interactive conference panel session that focused on faculty recruitment best practices. The article addresses faculty recruitment strategies that focus on the optimization of search…

  15. Overseas recruitment. The Spanish acquisitions.

    PubMed

    Mathie, Tony

    2002-12-01

    A pilot project, funded by the Department of Health, resulted in the recruitment of 17 Spanish GPs to practices in Liverpool and Manchester. The doctors are employed on two-year contracts with a salary of Pounds 45,000. The scheme has shown that Spanish GPs are not experienced in interviewing potential employers, or negotiating job plans. The initiative includes a four-month induction period in a training practice. The importance of language support and a senior champion for the scheme are key factors. PMID:12500596

  16. Cadmium and mercury in sediment and burrowing mayfly nymphs (Hexagenia) in the upper Mississippi River, USA

    USGS Publications Warehouse

    Beauvais, S.L.; Wiener, J.G.; Atchison, G.J.

    1995-01-01

    Longitudinal patterns in the cadmium and mercury content of burrowing mayflies (Hexagenia) and surrounding sediments were examined along a 572-km reach of the upper Mississippi River. Surficial sediments and Hexagenia nymphs were sampled in 1989 at 12 sites extending from Pool 2 through Pool 16 and analyzed for total recoverable cadmium and total mercury. In sediment and nymphs, concentrations of both metals were highest in Pools 2, 3, and 4, which are just downstream from the Twin Cities (Minneapolis-St. Paul, Minnesota) metropolitan area, the primary anthropogenic source of metals to the studied reach of river. Concentrations of the two metals in sediments indicated a significant anthropogenic contribution, which was most pronounced for cadmium. The cadmium concentrations in surficial sediment varied less than 3-fold (range, 1.19-3.23 mu g/g dry weight) among the 12 sites, whereas concentrations in Hexagenia varied almost 20-fold (range, 0.13-2.35 mu g/g dry weight). Nymphs from Pools 2-4 had much greater concentrations of cadmium than nymphs from sites further downstream, even though the mean concentration of cadmium in sediment from Pools 2-4 (3.0 mu g/g) was just twice that(1.6 mu g/g) for the nine sites downstream. Mercury in sediments from the 12 sites ranged from 0.038 to 0.165 mu g/g dry weight, averaging 0.14 mu g/g in Pools 2-4 and 0.056 mu g/g in the nine sites downstream. In nymphs, mercury concentrations ranged from 0.041 to 0.134 mu g/g dry weight. The bioavailability of sediment-associated cadmium seemed greater in Pools 2, 3, and 4 than in the sites further downstream, based on the relative cadmium concentrations in Hexagenia nymphs and sediment. Moreover, it is concluded that the trapping of sediment and associated metals in Lake Pepin (a natural riverine lake in Pool 4) significantly reduces the exposure of the ecosystem further downstream to metals from the Twin Cities and other upstream anthropogenic sources.

  17. An ichnofabric approach to the depositional interpretation of the intensely burrowed Bateig Limestone, Miocene, SE Spain

    NASA Astrophysics Data System (ADS)

    de Gibert, Jordi M.; Goldring, Roland

    2007-01-01

    The foraminiferal-rich pelagic Bateig Limestone forms several varieties of the important building stones quarried at Bateig Hill in southeastern Spain. Three principal ichnofabrics ( Bichordites, mottled- Palaeophycus and mottled- Ophiomorpha) are recognized, which are present in at least two (possibly up to four) repeated successions (cycles). Each succession begins with an erosional event. The Bichordites ichnofabric represents a new type of facies, formed as thin turbidity/grain flow, stratiform units derived from sediment slips off a fault into deep water. Each slipped unit became almost completely bioturbated by infaunal echinoids, colonizing by lateral migration. Because of the thinness of the units, successive colonizations tended to truncate the underlying burrows giving rise to a pseudo-stratification. As the Bichordites ichnofabric accumulated on the fault apron, thus reducing the effective height of the fault scarp, the substrate gradually came under the influence of currents traversing the shelf. This led to a change in hydraulic regime, and to the mottled- Palaeophycus and mottled- Ophiomorpha ichnofabrics in sediment deposited under bed load transport, and associated with laminar and cross-stratified beds and local muddy intervals. Reactivation of the fault triggered erosion and channeling and a return to grain flow sedimentation, and to the Bichordites ichnofabric of the succeeding cycle. The highest unit of the Bateig Limestone is formed entirely of cross-stratified calcarenites with occasional Ophiomorpha ( Ophiomorpha-primary lamination ichnofabric) and is similar to many shallow marine facies but they still bear a significant content of pelagic foraminifera. The sedimentary setting bears resemblance with that described for the Pleistocene Monte Torre Paleostrait and the modern Strait of Messina (Italy), where the narrow morphology of the depositional area enhanced tidal currents and allowed for high-energy sandy deposition in relatively deep

  18. Comparison of Burrowing and Stimuli-Evoked Pain Behaviors as End-Points in Rat Models of Inflammatory Pain and Peripheral Neuropathic Pain

    PubMed Central

    Muralidharan, Arjun; Kuo, Andy; Jacob, Meera; Lourdesamy, Jacintha S.; Carvalho, Lara Melo Soares Pinho De; Nicholson, Janet R.; Corradini, Laura; Smith, Maree T.

    2016-01-01

    Establishment and validation of ethologically-relevant, non-evoked behavioral end-points as surrogate measures of spontaneous pain in rodent pain models has been proposed as a means to improve preclinical to clinical research translation in the pain field. Here, we compared the utility of burrowing behavior with hypersensitivity to applied mechanical stimuli for pain assessment in rat models of chronic inflammatory and peripheral neuropathic pain. Briefly, groups of male Sprague-Dawley rats were habituated to the burrowing environment and trained over a 5-day period. Rats that burrowed ≤ 450 g of gravel on any 2 days of the individual training phase were excluded from the study. The remaining rats received either a unilateral intraplantar injection of Freund's complete adjuvant (FCA) or saline, or underwent unilateral chronic constriction injury (CCI) of the sciatic nerve- or sham-surgery. Baseline burrowing behavior and evoked pain behaviors were assessed prior to model induction, and twice-weekly until study completion on day 14. For FCA- and CCI-rats, but not the corresponding groups of sham-rats, evoked mechanical hypersensitivity developed in a temporal manner in the ipsilateral hindpaws. Although burrowing behavior also decreased in a temporal manner for both FCA-and CCI- rats, there was considerable inter-animal variability. By contrast, mechanical hyperalgesia and mechanical allodynia in the ipsilateral hindpaws of FCA- and CCI-rats respectively, exhibited minimal inter-animal variability. Our data collectively show that burrowing behavior is altered in rodent models of chronic inflammatory pain and peripheral neuropathic pain. However, large group sizes are needed to ensure studies are adequately powered due to considerable inter-animal variability. PMID:27242458

  19. Recruitment to a ritual role.

    PubMed

    Paul, L

    1975-01-01

    In the Zutuhil-Maya community of San Pedro la Laguna, a Guatemalan highland settlement with a population of 5000 Indians, midwives are recruited from the pool of married women in the 35-40 year age range who have heavy responsibilities as wives and mothers. They are relatively few in number and carry heavier patient loads than midwives in other communities. Their office is owed to divine mandate, and their work is guided by supernatural tutelaries. Duties of the midwives in this community include ritual performances. As sacred professionals, Pedrano midwives enjoy high status. The biography of Juana, a prototypical midwife, is recounted to illustrate how some Pedrano women do manage to become midwives. In San Pedro, midwives are born and not made, yet this is only the 1st step in the selection process. The common elements of the pattern of selection and recruitment include birth signs, enigmatic dreams in preadolescent years, the onset during married life of misforture and persisting illness accompanied by dream revelation, confirmation by a shaman of the woman's true destiny, discovery of strange objects mysteriously placed in her path, and disappearance of ill health and ill fortune upon beginning practice. The women who go this entire route and become successful midwives tend to share certain characteristics related to family background, parental expectation, and economic situation. PMID:12336264

  20. Improvement Text Compression Performance Using Combination of Burrows Wheeler Transform, Move to Front, and Huffman Coding Methods

    NASA Astrophysics Data System (ADS)

    Aprilianto, Mohammada; Abdurohman, Maman

    2014-04-01

    Text is a media that is often used to convey information in both wired and wireless-based network. One limitation of the wireless system is the network bandwidth. In this study we implemented a text compression application with lossless compression technique using combination of Burrows wheeler transform, move to front, and Huffman coding methods. With the addition of the compression of the text, it is expected to save network resources. This application provides information about compression ratio. From the testing process, it concludes that text compression with only Huffman coding method will be efficient when the number of text characters are above 400 characters, meanwhile text compression with burrows wheeler transform, move to front, and Huffman coding methods will be efficient when the number of text characters are above 531 characters. Combination of these methods are more efficient than just Huffman coding when the number of text characters are above 979 characters. The more characters that are compressed and the more patterns of the same symbol, the better the compression ratio.

  1. American badgers selectively excavate burrows in areas used by black-footed ferrets: implications for predator avoidance

    USGS Publications Warehouse

    Eads, David A.; Biggins, Dean E.; Livieri, Travis M.; Millspaugh, Joshua J.

    2013-01-01

    We evaluated how American badgers (Taxidea taxus) might exert selective pressure on black-footed ferrets (Mustela nigripes) to develop antipredator defenses. In a colony of black-tailed prairie dogs (Cynomys ludovicianus) in South Dakota, badgers concentrated their activities where burrow openings and prairie dogs were abundant, a selective behavior that was exhibited by ferrets in the same colony. Badgers excavated burrows more often when in areas recently used by a ferret, suggesting that badgers hunt ferrets or steal prey from ferrets, or both. We also conducted an analysis of survival studies for ferrets and Siberian polecats (M. eversmanii) released onto prairie dog colonies. This polecat is the ferret's ecological equivalent but evolved without a digging predator. Badgers accounted for 30.0% of predation on polecats and 5.5% of predation on ferrets. In contrast, both polecats and ferrets have evolutionary experience with canids, providing a plausible explanation for the similar relative impact of coyotes (Canis latrans) on them (65.0% and 67.1% of predation, respectively). We hypothesize that ferrets and badgers coexist because ferrets are superior at exploitation competition and are efficient at avoiding badgers, and badgers are superior at interference competition.

  2. Effects of cadmium-spiked sediment on cadmium accumulation and bioturbation by nymphs of the burrowing mayfly Hexagenia bilineata

    USGS Publications Warehouse

    Bartsch, Michelle; Cope, W. Gregory; Rada, Ronald G.

    1999-01-01

    We assessed accumulation of cadmium (Cd) and bioturbation by nymphs of the burrowing mayfly Hexagenia bilineata as indicators of exposure to Cd-spiked sediment in a 21-d test. Surficial sediments (top 5 cm) from Pool 7 of the Upper Mississippi River were spiked with Cd to concentrations of 3, 7, and 15 µg Cd g-1 dry weight. The experimental design was completely randomized, with three Cd-spiked sediment treatments plus an unspiked sediment control (1 µg Cd g-1 dry weight), and 10 nymphs in each of six replicates per treatment. Nymphs accumulated Cd during the 21-d exposure; mean concentrations varied from 0.22 to 6.24 µg g-1 dry weight, and tissue concentrations were correlated with Cd concentration in unfiltered test water (r = 0.93, P -1 treatment (our greatest exposure concentration) did not differ significantly from the control. Concentrations of Cd in unfiltered, overlying test water increased significantly within treatments during the test, indicating that nymphs mobilized sediment-associated Cd into the overlying water, presumably through burrowing and respiratory activities.

  3. Effects of cadmium-spiked sediment on cadmium accumulation and bioturbation by nymphs of the burrowing mayfly Hexagenia bilineata

    USGS Publications Warehouse

    Bartsch, M.R.; Cope, W.G.; Rada, R.G.

    1999-01-01

    We assessed accumulation of cadmium (Cd) and bioturbation by nymphs of the burrowing mayfly Hexagenia bilineata as indicators of exposure to Cd- spiked sediment in a 21-d test. Surficial sediments (top 5 cm) from Pool 7 of the Upper Mississippi River were spiked with Cd to concentrations of 3, 7, and 15 ??g Cd g-1 dry weight. The experimental design was completely randomized, with three Cd-spiked sediment treatments plus an unspiked sediment control (1 ??g Cd g-1 dry weight), and 10 nymphs in each of six replicates per treatment. Nymphs accumulated Cd during the 21-d exposure; mean concentrations varied from 0.22 to 6.24 ??g g-1 dry weight, and tissue concentrations were correlated with Cd concentration in unfiltered test water (r = 0.93, P < 0.01) and test sediment (r = 0.93, P < 0.01). The effect of Cd on bioturbation by nymphs, as indicated by turbidity, differed significantly among treatments (P = 0.045) and over time within treatments (P = 0.01). Turbidity progressively decreased as Cd concentration in the sediment increased, up to 7 ??g g-1; however, turbidity in the 15 ??g g-1 treatment (our greatest exposure concentration) did not differ significantly from the control. Concentrations of Cd in unfiltered, overlying test water increased significantly within treatments during the test, indicating that nymphs mobilized sediment-associated Cd into the overlying water, presumably through burrowing and respiratory activities.

  4. Diaphragm recruitment during nonrespiratory activities.

    PubMed

    Al-Bilbeisi, F; McCOOL, F D

    2000-08-01

    We previously found that weight lifters could generate greater inspiratory pressures and had more diaphragm mass than control subjects. We postulated that the weight-lifting activity itself provided a strength-training stimulus to the diaphragm. To evaluate the extent to which the diaphragm is recruited during strenuous nonrespiratory activities, we measured transdiaphragmatic pressure (Pdi) in six healthy subjects during biceps curls, bench press, power lift, and sit-ups. Each maneuver was performed with and without added weight (control), and with and without an abdominal binder. The weighted maneuvers were performed either during inspiration or expiration. Maximal static transdiaphragmatic pressure (Pdi(max)) was measured during a combined inspiratory and expulsive maneuver. Group mean values of Pdi increased during all activities when compared with control (57 +/- 24 versus 18 +/- 10 cm H(2)O [mean +/- SD] [p < 0.001]), as task intensity increased (98 +/- 14 versus 35 +/- 13 cm H(2)O for high- and low-intensity activities, respectively) (p < 0.001), and with abdominal binding (75 +/- 25 versus 59 +/- 25 cm H(2)O) (p < 0.05). Peak levels of Pdi attained during the activities were 126 +/- 11 cm H(2)O or 0.65 +/- 0.09 of Pdi(max). Changes in gastric pressure accounted for 85 +/- 4% of the increase in Pdi during the activities whereas it accounted for only 58 +/- 9% of the rise in Pdi during the control activities (p < 0.001). We conclude that during a range of weight-lifting activities, the diaphragm is recruited and Pdi is raised to a level that may provide a significant strength-training stimulus to the diaphragm. PMID:10934070

  5. Recruitment strategies and colony size in ants.

    PubMed

    Planqué, Robert; van den Berg, Jan Bouwe; Franks, Nigel R

    2010-01-01

    Ants use a great variety of recruitment methods to forage for food or find new nests, including tandem running, group recruitment and scent trails. It has been known for some time that there is a loose correlation across many taxa between species-specific mature colony size and recruitment method. Very small colonies tend to use solitary foraging; small to medium sized colonies use tandem running or group recruitment whereas larger colonies use pheromone recruitment trails. Until now, explanations for this correlation have focused on the ants' ecology, such as food resource distribution. However, many species have colonies with a single queen and workforces that grow over several orders of magnitude, and little is known about how a colony's organization, including recruitment methods, may change during its growth. After all, recruitment involves interactions between ants, and hence the size of the colony itself may influence which recruitment method is used--even if the ants' behavioural repertoire remains unchanged. Here we show using mathematical models that the observed correlation can also be explained by recognizing that failure rates in recruitment depend differently on colony size in various recruitment strategies. Our models focus on the build up of recruiter numbers inside colonies and are not based on optimality arguments, such as maximizing food yield. We predict that ant colonies of a certain size should use only one recruitment method (and always the same one) rather than a mix of two or more. These results highlight the importance of the organization of recruitment and how it is affected by colony size. Hence these results should also expand our understanding of ant ecology. PMID:20694195

  6. Recruitment Strategies and Colony Size in Ants

    PubMed Central

    Planqué, Robert; van den Berg, Jan Bouwe; Franks, Nigel R.

    2010-01-01

    Ants use a great variety of recruitment methods to forage for food or find new nests, including tandem running, group recruitment and scent trails. It has been known for some time that there is a loose correlation across many taxa between species-specific mature colony size and recruitment method. Very small colonies tend to use solitary foraging; small to medium sized colonies use tandem running or group recruitment whereas larger colonies use pheromone recruitment trails. Until now, explanations for this correlation have focused on the ants' ecology, such as food resource distribution. However, many species have colonies with a single queen and workforces that grow over several orders of magnitude, and little is known about how a colony's organization, including recruitment methods, may change during its growth. After all, recruitment involves interactions between ants, and hence the size of the colony itself may influence which recruitment method is used—even if the ants' behavioural repertoire remains unchanged. Here we show using mathematical models that the observed correlation can also be explained by recognizing that failure rates in recruitment depend differently on colony size in various recruitment strategies. Our models focus on the build up of recruiter numbers inside colonies and are not based on optimality arguments, such as maximizing food yield. We predict that ant colonies of a certain size should use only one recruitment method (and always the same one) rather than a mix of two or more. These results highlight the importance of the organization of recruitment and how it is affected by colony size. Hence these results should also expand our understanding of ant ecology. PMID:20694195

  7. Recruiting African American smokers into intervention research: Relationships between recruitment strategies and participant characteristics.

    PubMed

    Webb, Monica S; Seigers, Danielle; Wood, Elizabeth A

    2009-02-01

    The purposes of this study were to (a) to describe an 8-month recruitment campaign to enroll African American smokers (N = 249) into a randomized controlled trial and (b) examine characteristics of participants recruited through proactive (face-to-face), reactive (television, radio, or newspaper ads inviting participants), and combination (both reactive and proactive) approaches. Reactive recruitment was most successful (43%), followed by proactive (31%), and combination (26%) recruitment. Compared to proactive recruitment, reactive recruitment was associated with lower nicotine dependence, and greater readiness to quit, processes of change engagement, and acculturation. Combination recruitment was associated with lower nicotine dependence and greater readiness to quit. The differences according to recruitment strategy could be used to tailor recruitment strategies for African American smokers. PMID:18767129

  8. Recruiting future neuroscientists: what asking the recruits can teach us.

    PubMed

    Willcockson, Irmgard U; Phelps, Cynthia L

    2004-12-01

    Many different strategies are used to recruit students into scientific research careers, including neuroscience research. These strategies are rarely based on knowledge about students; instead, activities are selected based on their ease of implementation. The goal of the LEARN Project is to encourage high school students into mental health science research using the theme of learning and memory. One intervention the authors developed is five Web-based biographies introducing students to contemporary neuroscientist role models studying learning and memory. To guide the design of this intervention, the authors created a survey to determine where students obtain career information and who and what influences their career selection. In a convenience sample of 124 students, the authors found that almost all students use the Internet for information about careers, in addition to consulting family members and teachers. Students' career selections are influenced most by family members, teachers, and people already in the field. The most important factors students look for in their future career are money, fun, and a good match between current interests and future careers. The data affirm the value of outreach efforts that go beyond students to include a broader audience of parents and teachers who play a critical role in career selection. PMID:15534043

  9. Health parties for African American study recruitment.

    PubMed

    Sadler, Georgia Robins; York, Crystal; Madlensky, Lisa; Gibson, Kathi; Wasserman, Linda; Rosenthal, Eric; Barbier, Leslie; Newman, Vicky A; Tso, Cindy

    2006-01-01

    Innovative strategies are needed to increase minorities' research participation. Using existing social networks within the African American community, "home health parties" were tested as a way to recruit African American women to a breast cancer control study. Parties included social, educational, and recruitment components. All women attending health parties consented, completed a survey, and received the study's preliminary breast cancer risk assessment. There were no differences in rates of participation for subsequent study components between women recruited via parties versus other methods. Health parties are viable recruitment strategies, reduce barriers to participation, provide a supportive environment, and are relatively inexpensive. PMID:17020516

  10. Interactions between Multiple Recruitment Drivers: Post-Settlement Predation Mortality and Flow-Mediated Recruitment

    PubMed Central

    Knights, Antony M.; Firth, Louise B.; Walters, Keith

    2012-01-01

    Background Dispersal is a primary driver in shaping the future distribution of species in both terrestrial and marine systems. Physical transport by advection can regulate the distance travelled and rate of propagule supply to a habitat but post-settlement processes such as predation can decouple supply from recruitment. The effect of flow-mediated recruitment and predation on the recruitment success of an intertidal species, the eastern oyster Crassostrea virginica was evaluated in two-replicated field experiments. Two key crab species were manipulated to test predator identity effects on oyster mortality. Findings Recruitment was ∼58% higher in high flow compared to low flow, but predation masked those differences. Predation mortality was primarily attributed to the blue crab Callinectes sapidus, whilst the mud crab Panopeus herbstii had no effect on recruit mortality. Recruit mortality from predation was high when recruit densities were high, but when recruit density was low, predation effects were not seen. Under high recruitment (supply), predation determined maximum population size and in low flow environments, recruitment success is likely determined by a combination of recruitment and resource limitation but not predation. Conclusions Four processes are demonstrated: (1) Increases in flow rate positively affect recruitment success; (2) In high flow (recruitment) environments, resource availability is less important than predation; (3) predation is an important source of recruit mortality, but is dependent upon recruit density; and (4) recruitment and/or resource limitation is likely a major driver of population structure and functioning, modifying the interaction between predators and prey. Simultaneous testing of flow-mediated recruitment and predation was required to differentiate between the role of each process in determining population size. Our results reinforce the importance of propagule pressure, predation and post-settlement mortality as

  11. Recruitment and post-recruit immigration affect the local population size of coral reef fishes

    NASA Astrophysics Data System (ADS)

    Lewis, A. R.

    1997-07-01

    This study quantifies the contributions of larval recruitment and post-recruit (juvenile and adult) immigration to net increases in population size for 150 species of fishes found on ten isolated coral patches or `bommies' (108-267 m2) within a typical reef of the Great Barrier Reef system. At least one third of the total number of recruits and immigrants to all bommies were post-recruit fishes, and movement between bommies in 136 species was detected at some time during the 22 month sampling period. The relative numbers of recruits and post-recruit immigrants per species varied widely within the assemblage, and between the replicate bommies. Populations of 95 species received both types of immigrants, 41 species had only post-recruit immigrants, and 14 species received only larval recruitment. In most species, recruitment occurred over the austral summer between October and February, while post-recruit movements occurred in both summer and winter. Rates of post-recruit immigration varied temporally within bommies, and pulses of post-recruits were less temporally concordant between bommies than pulses of recruits. This study is further evidence that post-settlement processes can have a significant effect on the local population size of reef fishes.

  12. Paleobotanical analysis of materials from fossil gopher burrows and upper pleistocene host deposits, the Kolyma River lower reaches

    NASA Astrophysics Data System (ADS)

    Lopatina, D. A.; Zanina, O. G.

    2006-10-01

    The comparative analysis of palynomorphs and plant megafossils (fruits, seeds, twigs, leaves) in the Upper Pleistocene host sediments and materials filling in fossil burrows of gophers, their coprolites included, at the Duvannyi Yar, Stanchikovskii Yar and Zelenyi Mys sites of the Kolyma Lowland is carried out. Genera Salix, Lychnis, Silene, Draba, Potentilla, Larix, and families Poaceae, Polygonaceae, Cyperaceae, Compositae, and Leguminosae are determined among palynological remains and megafossils. Factors responsible for qualitative and quantitative differences in taxonomic compositions of palynological and megafossil assemblages are biological peculiarities of plants, different character of fossilization of palynomorphs and large plant remains, geographic conditions, different genesis of assemblages (allochthonous for microfossils and autochthonous for megafossils), and inadequately known morphology of certain spore and pollen taxa. The comprehensive paleobotanical analysis leads to the conclusion that the study region was occupied in the Late Pleistocene by plant communities of humid to somewhat dryer tundra with separate areas of pioneering and steppe vegetation.

  13. The feeding habits of Austrolethops wardi, a gobiid fish inhabiting burrows of the thalassinidean shrimp Neaxius acanthus

    NASA Astrophysics Data System (ADS)

    Hung Liu, Ha Trieu; Kneer, Dominik; Asmus, Harald; Ahnelt, Harald

    2008-09-01

    The feeding habit of Austrolethops wardi (Gobiidae) in the seagrass beds of Barrang Lompo and Bone Batang Island in the Spermonde Archipelago, South West Sulawesi, Indonesia, was investigated through gut content analysis. The feeding preferences of this species are very similar on both islands: A. wardi, a burrow associate of Neaxius acanthus, was found to feed almost exclusively on seagrass (which was found in 100% of the investigated stomachs and made up >94% of food items). However, seagrass epiphytes (<5% of food items) and animal food (<1% of food items) occurred in the guts as well, the latter predominantly in terms of copepods and to a lesser degree in other small invertebrates. These results indicate that animal food is of little importance for A. wardi. Some specimens even contained no parts of animal food.

  14. Relationships between yolk androgens and nest density, laying date, and laying order in Western Burrowing Owls (Athene cunicularia hypugaea)

    USGS Publications Warehouse

    Welty, J.L.; Belthoff, J.R.; Egbert, J.; Schwabl, H.

    2012-01-01

    Increases in yolk androgens within and among avian clutches have been correlated with decreased incubation time, increased aggression within a nest, increased begging behaviour, decreased immune response, and decreased life span. Although the mechanisms that lead to variability in yolk androgens within and between clutches are not completely known, yolk androgens can be a function of both social and environmental conditions. We were interested in if and how nesting density, laying date, and laying order influenced yolk androgens in Western Burrowing Owls (Athene cunicularia hypugaea (Bonaparte, 1825)) in which nest density varies considerably. In 2006 and 2007, we used radioimmunoassay to quantify the concentrations of testosterone, 5a-dihydrotestosterone, and androstenedione in the egg yolks from one early and one latelaid egg in 47 nests of Burrowing Owls located in the Morley Nelson Snake River Birds of Prey National Conservation Area in southern Idaho. Nesting density had no detectable effect on yolk androgens. Yolk androgens varied temporally and peaked in the middle of the laying season while being low before and after this time period. Within nests, late-laid eggs had higher testosterone and dihydrotestosterone than early-laid eggs; adrostendione exhibited a similar pattern in one but not both years of our study. It is possible that the seasonal pattern in yolk androgens that we observed is related to aspects of mate quality for females or declining chances of fledging success for later nesting females, whereas rises in egg androgens between early and late eggs within clutches could reflect a mechanism to assist nestlings from late-laid eggs that hatch one to several days after their siblings to better compete for resources within the nest or promote survival in the presence of larger siblings.

  15. Burrower bugs (Heteroptera: Cydnidae) in peanut: seasonal species abundance, tillage effects, grade reduction effects, insecticide efficacy, and management.

    PubMed

    Chapin, Jay W; Thomas, James S

    2003-08-01

    Pitfall traps placed in South Carolina peanut, Arachis hypogaea (L.), fields collected three species of burrower bugs (Cydnidae): Cyrtomenus ciliatus (Palisot de Beauvois), Sehirus cinctus cinctus (Palisot de Beauvois), and Pangaeus bilineatus (Say). Cyrtomenus ciliatus was rarely collected. Sehirus cinctus produced a nymphal cohort in peanut during May and June, probably because of abundant henbit seeds, Lamium amplexicaule L., in strip-till production systems. No S. cinctus were present during peanut pod formation. Pangaeus bilineatus was the most abundant species collected and the only species associated with peanut kernel feeding injury. Overwintering P. bilineatus adults were present in a conservation tillage peanut field before planting and two to three subsequent generations were observed. Few nymphs were collected until the R6 (full seed) growth stage. Tillage and choice of cover crop affected P. bilineatus populations. Peanuts strip-tilled into corn or wheat residue had greater P. bilineatus populations and kernel-feeding than conventional tillage or strip-tillage into rye residue. Fall tillage before planting a wheat cover crop also reduced burrower bug feeding on peanut. At-pegging (early July) granular chlorpyrifos treatments were most consistent in suppressing kernel feeding. Kernels fed on by P. bilineatus were on average 10% lighter than unfed on kernels. Pangaeus bilineatus feeding reduced peanut grade by reducing individual kernel weight, and increasing the percentage damaged kernels. Each 10% increase in kernels fed on by P. bilineatus was associated with a 1.7% decrease in total sound mature kernels, and kernel feeding levels above 30% increase the risk of damaged kernel grade penalties. PMID:14503585

  16. Urban pollution of sediments: Impact on the physiology and burrowing activity of tubificid worms and consequences on biogeochemical processes.

    PubMed

    Pigneret, M; Mermillod-Blondin, F; Volatier, L; Romestaing, C; Maire, E; Adrien, J; Guillard, L; Roussel, D; Hervant, F

    2016-10-15

    In urban areas, infiltration basins are designed to manage stormwater runoff from impervious surfaces and allow the settling of associated pollutants. The sedimentary layer deposited at the surface of these structures is highly organic and multicontaminated (mainly heavy metals and hydrocarbons). Only few aquatic species are able to maintain permanent populations in such an extreme environment, including the oligochaete Limnodrilus hoffmeisteri. Nevertheless, the impact of urban pollutants on these organisms and the resulting influence on infiltration basin functioning remain poorly studied. Thus, the aim of this study was to determine how polluted sediments could impact the survival, the physiology and the bioturbation activity of L. hoffmeisteri and thereby modify biogeochemical processes occurring at the water-sediment interface. To this end, we conducted laboratory incubations of worms, in polluted sediments from infiltration basins or slightly polluted sediments from a stream. Analyses were performed to evaluate physiological state and burrowing activity (X-ray micro-tomography) of worms and their influences on biogeochemical processes (nutrient fluxes, CO2 and CH4 degassing rates) during 30-day long experiments. Our results showed that worms exhibited physiological responses to cope with high pollution levels, including a strong ability to withstand the oxidative stress linked to contamination with heavy metals. We also showed that the presence of urban pollutants significantly increased the burrowing activity of L. hoffmeisteri, demonstrating the sensitivity and the relevance of such a behavioural response as biomarker of sediment toxicity. In addition, we showed that X-ray micro-tomography was an adequate technique for accurate and non-invasive three-dimensional investigations of biogenic structures formed by bioturbators. The presence of worms induced stimulations of nutrient fluxes and organic matter recycling (between +100% and 200% of CO2 degassing rate

  17. Considering the Audience: Air Force Recruiting Presentations

    ERIC Educational Resources Information Center

    Malone, Darek L.

    2012-01-01

    Each Air Force recruiter is formally trained in public speaking and the art of salesmanship or persuasion. These recruiters communicate to thousands of high school students each year through presentations in classrooms, auditoriums and other venues as part of their assigned duties. Persuasive presentations are public speaking events specifically…

  18. Recruitment and Retention in Rural America.

    ERIC Educational Resources Information Center

    Helge, Doris I.; Marrs, Lawrence W.

    Social isolation, extreme weather conditions, inadequate housing, and low salaries often characterizing rural areas cause problems in recruiting and retaining special education personnel. Successful interviewers for rural districts must include four components in their recruitment strategies: the use of intrinsic rather than extrinsic motivators,…

  19. Minority Teacher Recruitment and Retention Strategies

    ERIC Educational Resources Information Center

    Kearney-Gissendaner, Janet E.

    2010-01-01

    The tools and resources in this book help school leaders seamlessly incorporate minority teacher recruitment and retention programs into current human-resources activities. With details about exemplary minority teacher recruitment and retention programs, this book also showcases strategies for how to replicate such programs in your own school or…

  20. Triton College Faculty Recruitment Action Plan (FRAP).

    ERIC Educational Resources Information Center

    Triton Coll., River Grove, IL.

    Triton College's (Illinois) Faculty Recruitment Action Plan (FRAP) provides a detailed guide to hiring new faculty, focusing on the desired characteristics of new faculty; marketing and recruitment strategies; employment incentives; the application, interviewing, and selection process; new faculty orientation; a timeline for implementation; cost…

  1. A Community-Based Recruitment Program.

    ERIC Educational Resources Information Center

    DeCosmo, Richard D.; Baratta, Mary Kathryne

    1979-01-01

    Analyses community-based recruitment techniques initiated by Moraine Valley Community College, Illinois, to stabilize enrollment, expand participation of the under-served, and increase the pool of college attendees. Delineates the eight goals of recruitment and the plan implemented at Moraine Valley. Discusses major activities and results. (CAM)

  2. 29 CFR 36.310 - Recruitment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited... apply shall not discriminate on the basis of sex in the recruitment and admission of students....

  3. 5 CFR 330.402 - Direct recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Direct recruitment. 330.402 Section 330.402 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS RECRUITMENT, SELECTION, AND PLACEMENT (GENERAL) Positions Restricted to Preference Eligibles § 330.402 Direct...

  4. 29 CFR 36.310 - Recruitment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited... apply shall not discriminate on the basis of sex in the recruitment and admission of students....

  5. 29 CFR 36.310 - Recruitment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited... apply shall not discriminate on the basis of sex in the recruitment and admission of students....

  6. School Board Member Recruitment in Ontario.

    ERIC Educational Resources Information Center

    Cistone, Peter J.

    Employing a process model of political recruitment, this study investigated the relative impact of a school district's social, economic, and political structure on school board member recruitment. The process data were collected by means of structured interviews with neophyte school board members in a stratified sample of school boards in the…

  7. Personnel Recruitment and Retention in Rural America.

    ERIC Educational Resources Information Center

    Helge, Doris; Marrs, Lawrence W.

    Recruitment and retention of special education teachers and related services staff have been persistent problems of rural school districts nationwide. High teacher attrition rates have serious ramifications for personnel development and program stability. Effective recruitment strategies for rural areas have four main components: (1) emphasis on…

  8. 45 CFR 83.12 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... each of its training programs, make comparable efforts to recruit members of each sex in the geographic... members or students, or which provide a service for, only members of one sex unless such entity can... on the basis of sex in selection for a training program. (b) Recruitment practices. A...

  9. 45 CFR 83.12 - Recruitment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... each of its training programs, make comparable efforts to recruit members of each sex in the geographic... members or students, or which provide a service for, only members of one sex unless such entity can... on the basis of sex in selection for a training program. (b) Recruitment practices. A...

  10. A marketing approach to physician recruitment.

    PubMed

    Wilhide, S D

    1992-01-01

    Physician recruiting can be a time-consuming and frustrating task, writes Stephen Wilhide, M.S.W., M.P.H., and thus it requires careful planning. A marketing approach to recruiting is one way to assure that all the necessary steps are taken for a successful conclusion to the process. PMID:10119002

  11. Turf Wars: School Administrators and Military Recruiting

    ERIC Educational Resources Information Center

    Lagotte, Brian W.

    2014-01-01

    Although a decade has passed since passage, few have noticed that section 9528 in No Child Left Behind (NCLB) mandates schools to assist military recruiting. This article focuses on administrators' responsibility to inform parents of their privacy rights and the struggle to manage recruiting in schools. I highlight two conclusions with policy…

  12. 32 CFR 240.7 - Recruitment program.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 2 2012-07-01 2012-07-01 false Recruitment program. 240.7 Section 240.7 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS DOD INFORMATION ASSURANCE SCHOLARSHIP PROGRAM (IASP) § 240.7 Recruitment program. (a) Annually, in November, the DoD IASP Executive...

  13. Guide to Recruitment: A Manual for Head Start Personnel in Recruiting Handicapped Children.

    ERIC Educational Resources Information Center

    Hodskins, David, Ed.

    Intended for Head Start personnel, the manual outlines a recruitment campaign for identifying and enrolling children who have health impairments requiring special education and related services. Briefly covered are the following topics: rationale for the recruitment compaign; targets of recruitment (which include Head Start families, the general…

  14. Recruiting Underrepresented Minorities to Chiropractic Colleges

    PubMed Central

    Callender, Alana

    2006-01-01

    Background: Admissions departments at chiropractic colleges across the United States are under continual pressure to recruit students. The underrepresented minority populations in the United States are potential markets for chiropractic patients, students, and doctors. Objective: To assess the current diversity recruiting practices of the chiropractic colleges. Methods: Directors of admissions of the chiropractic colleges were polled to identify recruiting programs and their success. Results: Sixteen of the 17 colleges were polled. Nine of the respondents had no program for targeted underserved populations and seven did have such a program. Five colleges employed several methods to work with universities to recruit underserved populations. Other strategies included outreach via student groups and alumni recruiters. Conclusion: Programs to attract minority students can be created and infrastructure can be provided but they are nearly useless without role models. Encouraging alumni participation to raise awareness of chiropractic in minority communities may be a step toward a profession more reflective of America’s population. PMID:18483633

  15. Natural History Museum Sound Archive I: Orthoptera: Gryllotalpidae Leach, 1815, including 3D scans of burrow casts of Gryllotalpa gryllotalpa (Linnaeus, 1758) and Gryllotalpa vineae Bennet-Clark, 1970

    PubMed Central

    Broom, Yoke-Shum

    2015-01-01

    Abstract Background The Natural History Museum (NHM) sound archive contains recordings of Gryllotalpidae, and the NHM collection holds plaster casts of the burrows of two species. These recordings and burrows have until now not been made available through the NHM's collection database, making it hard for researchers to make use of these resources. New information Eighteen recordings of mole crickets (three identified species) held by the NHM have been made available under open licenses via BioAcoustica. 3D scans of the burrows of Gryllotalpa gryllotalpa (Linnaeus, 1758) and Gryllotalpa vineae Bennet-Clark, 1970 have been made available via the NHM Data Portal. PMID:26752971

  16. Investigating the Impact of a Burrowing Shrimp on Biogeochemical Processes and Microbial Communities in a Shallow Lagoon, Catalina Harbor, California, U.S.A.

    NASA Astrophysics Data System (ADS)

    Bertics, V. J.; Ziebis, W.

    2007-05-01

    Understanding the interactions between the activity of macrofauna organisms and the biogeochemistry and microbiology of marine sediments is crucial in evaluating marine ecosystem functioning and nutrient cycling. Burrows built by different organisms often vary in architecture, size, and permanence, making it difficult to extrapolate from one organism to another and from one location to another, the impact that bioturbation or bioirrigation has on the local biogeochemical processes. The overall goal of this study is to combine interdisciplinary approaches to assess the impact of the ghost shrimp Callianassa californiensis, on the biogeochemistry of a shallow lagoon located in Catalina Harbor, California, USA. Field investigations were performed in the lagoon along a transect from the shoreline out to 10 m. The area is bioturbated by Callianassa californiensis with a linear increase in burrows with distance from the shore (R2 = 0.9481). Highest numbers were found at the 10 m distance with approximately 866 burrows m-2. Oxygen penetration depths were determined using Clark-type amperometric microsensors. These measurements were accompanied by detailed analyses of sediment and pore water parameters (porosity, TOC, H2S, NH4+, NO3-, Fe (II)/Fe (III)) by taking sediment cores at 2 m intervals along the transect and slicing these cores in a vertical resolution of 1 cm. Microbial abundances with sediment depth and along the transect were determined by direct counts (AODC) and microbial diversity patterns were analyzed using the molecular finger printing method ARISA (Automated rRNA Intergenic Spacer Analysis). In addition to the field studies, we examined the effects of the shrimp burrows in more detail by using narrow aquaria (40 cm x 15 cm x 5 cm). Each aquarium was filled with sediment collected from the study site, populated by one or two shrimps, and placed in a flowing seawater system. The front walls of the aquaria were perforated with holes in a 1 cm grid that were

  17. Recruiting Research Participants at Community Education Sites

    PubMed Central

    SADLER, GEORGIA ROBINS; PETERSON, MELANIE; WASSERMAN, LINDA; MILLS, PAUL L.; MALCARNE, VANESSA L.; ROCK, CHERYL; ANCOLI-ISRAEL, SONIA; MOORE, AMANDA; WELDON, RAI-NESHA; GARCIA, TENISHA; KOLODNER, RICHARD D.

    2006-01-01

    Background Minority groups are underrepresented in research, making it difficult to apply medical advances with confidence. In this study, we explored whether community-based cancer education sites and educators serving the African American community could be used to recruit minority participants to research. Methods We invited Individuals at community education sites to provide buccal scrapings, saliva samples, psychometric data, and personal information anonymously. Results Culturally aligned community sites (100%) collaborated in the research recruitment, as did 83% of the individuals at those sites. Conclusion Community-based education sites offer exceptional promise for teaching about research benefits and recruiting members of minority groups to research studies. PMID:16497136

  18. Recruiting physicians: avoiding the legal minefield.

    PubMed

    Copeland, W M

    1992-01-01

    This article identifies and discusses the legal problems and pitfalls associated with the implementation of a physician recruitment program. Careful structuring is necessary to strike a balance meeting the requirements of both the Internal Revenue Code and the Medicare fraud and abuse provisions. The various tax considerations that may affect physician recruitment are comprehensively analyzed. Similar analysis is made of the Medicare fraud and abuse statute. Also included is a list of items that must be taken into consideration when embarking on a physician recruitment program. PMID:10118592

  19. Improving healthcare recruitment: the jupiter medical center experience.

    PubMed

    Uomo, Paul Dell; Schwieters, Jill

    2009-04-01

    Hospitals that want to improve their recruitment efforts should: Make recruitment a priority within the organization. Take steps to reduce high vacancy rates and turnover among first-year employees. Develop a recruitment marketing plan for key positions. Establish human resources metrics to track costs and effectiveness of recruiting efforts. Enhance the recruitment process for hiring managers and job candidates. PMID:19391571

  20. Electronic Recruiting: An Alternative with Many Advantages.

    ERIC Educational Resources Information Center

    Hicks, Mary J.; Woo, Tony Chi-Hung

    1989-01-01

    Discusses electronic recruiting, a process which enables employers to directly access computerized college student resume information via modem. Addresses such advantages as providing up-to-date student information and alleviating paperwork. Provides an example of this system. (BHK)

  1. Assessment of short and long-term effects of imidacloprid on the burrowing behaviour of two earthworm species (Aporrectodea caliginosa and Lumbricus terrestris) by using 2D and 3D post-exposure techniques.

    PubMed

    Dittbrenner, Nils; Moser, Isabelle; Triebskorn, Rita; Capowiez, Yvan

    2011-09-01

    Adverse effects of agrochemicals on earthworms' burrowing behaviour can have crucial impacts on the entire ecosystem. In the present study, we have therefore assessed short- and long-term effects on burrowing behaviour in the earthworm species Aporrectodea caliginosa and Lumbricus terrestris after exposure to a range of imidacloprid concentrations (0.2-4 mg kg(-1) dry weight (DW)) for different exposure times (1, 7, 14 d). 2D-terraria were used for the examination of post-exposure short-term effects (24-96 h), while post-exposure long-term effects were assessed by means of X-ray burrow reconstruction in three dimensional soil cores (6 weeks). For the latter each core was incubated with two specimens of L. terrestris and four of A. calignosa. Short-term effects on the burrowing behaviour (2D) of A. caliginosa were already detected at the lowest test concentration (0.2 mg kg(-1) DW), whereas such effects in L. terrestris were not observed until exposure to concentrations 10 times higher (2 mg kg(-1) DW). For both species tested in the 2D-terraria, "total burrow length after 24 h" and "maximal burrow depth after 24 h" were the most sensitive endpoints. 3D reconstructions of the burrow systems made by both earthworm species in the repacked soil cores revealed a significant linear decrease in burrow volume with increasing imidacloprid concentration. Since many of the observed effects occurred at imidacloprid concentrations relevant to natural conditions and since reduced activities of earthworms in soils can have crucial impacts on the ecosystem level, our results are of environmental concern. PMID:21632088

  2. Impact of elevated levels of CO2 on animal mediated ecosystem function: the modification of sediment nutrient fluxes by burrowing urchins.

    PubMed

    Widdicombe, S; Beesley, A; Berge, J A; Dashfield, S L; McNeill, C L; Needham, H R; Øxnevad, S

    2013-08-30

    A mesocosm experiment was conducted to quantify the relationships between the presence and body size of two burrowing heart urchins (Brissopsis lyrifera and Echinocardium cordatum) and rates of sediment nutrient flux. Furthermore, the impact of seawater acidification on these relationships was determined during this 40-day exposure experiment. Using carbon dioxide (CO2) gas, seawater was acidified to pHNBS 7.6, 7.2 or 6.8. Control treatments were maintained in natural seawater (pH≈8.0). Under normocapnic conditions, burrowing urchins were seen to reduce the sediment uptake of nitrite or nitrate whilst enhancing the release of silicate and phosphate. In acidified (hypercapnic) treatments, the biological control of biogeochemical cycles by urchins was significantly affected, probably through the combined impacts of high CO2 on nitrifying bacteria, benthic algae and urchin behaviour. This study highlights the importance of considering biological interactions when predicting the consequences of seawater acidification on ecosystem function. PMID:23218873

  3. The rattling sound of rattlesnakes (Crotalus viridis) as a communicative resource for ground squirrels (Spermophilus beecheyi) and burrowing owls (Athene cunicularia).

    PubMed

    Owings, Donald H; Rowe, Matthew P; Rundus, Aaron S

    2002-06-01

    Animal communication involves very dynamic processes that can generate new uses and functions for established communicative activities. In this article, the authors describe how an aposematic signal, the rattling sound of rattlesnakes (Crotalus viridis), has been exploited by 2 ecological associates of rattlesnakes: (a) California ground squirrels (Spermophilus beecheyi) use incidental acoustic cues in rattling sounds to assess the danger posed by the rattling snake, and (b) burrowing owls (Athene cunicularia) defend themselves against mammalian predators by mimicking the sound of rattling. The remarkable similarity between the burrowing owl's defensive hiss and the rattlesnake's rattling reflects both exaptation and adaptation. Such exploitation of the rattling sound has favored alternations in both the structure and the deployment of rattling by rattlesnakes. PMID:12083617

  4. Chilocoris laevicollis Horváth, 1919, and Ch. umbricola Linnavuori, 1993-two trogloxenic burrower bugs recorded for the first time in Gabon (Central Africa).

    PubMed

    Lis, Barbara; Lis, Jerzy A

    2016-01-01

    First country records of two burrower bugs, Chilocoris laevicollis, and Ch. umbricola (Hemiptera: Heteroptera: Cydnidae) from Gabon (Central Africa) are presented. The study was based on the specimens collected by Dr. V. Aellen, a well-known Swiss speleologist, taken from two caves near Lastoursville in the Gabonese Republic. Diagnostic characters for both recorded species are provided, and data on their biology and distribution are summarized. PMID:27395502

  5. The relative roles of the parasol-like tail and burrow shuttling in thermoregulation of free-ranging Cape ground squirrels, Xerus inauris.

    PubMed

    Fick, Linda G; Kucio, Tomasz A; Fuller, Andrea; Matthee, André; Mitchell, Duncan

    2009-03-01

    As small arid-zone mammals, Cape ground squirrels (Xerus inauris) are unusual in being diurnally active. It is postulated that they remain active during the day by using their parasol-like tails to shade their bodies whilst foraging. However, no studies have continuously measured body temperature to determine the effect of using the tail as a parasol, relative to other thermoregulatory behaviours, such as burrow retreat. We caught four free-ranging Cape ground squirrels (673+/-36 g) and surgically implanted miniature temperature-sensitive data loggers into their abdomens, to record body temperature every 5 min to an accuracy of 0.04 degrees C, before they were released back into their home range and observed for two weeks. Mean daily peak black globe temperature was 41 degrees C, and daily peak body temperature reached 40 degrees C. Ground squirrels raised their tails significantly more often at globe temperatures above 30 degrees C, but raising the tail did not decrease body temperature, nor prevent body temperature rising. Ground squirrels retreated to burrows, at 18 degrees C, significantly more often at high body temperatures and body temperature dropped 1-2 degrees C before re-emergence. We believe that the tail was raised to provide thermal comfort during high solar radiation exposure, and that burrow retreat was employed to dissipate a heat load and remain active diurnally. PMID:19041951

  6. Molecular Phylogeny Supports Repeated Adaptation to Burrowing within Small-Eared Shrews Genus of Cryptotis (Eulipotyphla, Soricidae)

    PubMed Central

    He, Kai; Woodman, Neal; Boaglio, Sean; Roberts, Mariel; Supekar, Sunjana; Maldonado, Jesús E.

    2015-01-01

    Small-eared shrews of the New World genus Cryptotis (Eulipotyphla, Soricidae) comprise at least 42 species that traditionally have been partitioned among four or more species groups based on morphological characters. The Cryptotis mexicana species group is of particular interest, because its member species inhibit a subtly graded series of forelimb adaptations that appear to correspond to locomotory behaviors that range from more ambulatory to more fossorial. Unfortunately, the evolutionary relationships both among species in the C. mexicana group and among the species groups remain unclear. To better understand the phylogeny of this group of shrews, we sequenced two mitochondrial and two nuclear genes. To help interpret the pattern and direction of morphological changes, we also generated a matrix of morphological characters focused on the evolutionarily plastic humerus. We found significant discordant between the resulting molecular and morphological trees, suggesting considerable convergence in the evolution of the humerus. Our results indicate that adaptations for increased burrowing ability evolved repeatedly within the genus Cryptotis. PMID:26489020

  7. Comparative ventilatory strategies of acclimated rats and burrowing plateau pika (Ochotona curzoniae) in response to hypoxic-hypercapnia.

    PubMed

    Pichon, Aurélien; Voituron, Nicolas; Bai, Zhenzhong; Jeton, Florine; Tana, Wuren; Marchant, Dominique; Jin, Guoen; Richalet, Jean-Paul; Ge, Ri-Li

    2015-09-01

    The objective of this study was to compare the different ventilatory strategies that help in coping with hypoxic-hypercapnia environment among two species: use acclimated rats and plateau pikas (Ochotona curzoniae) that live in Tibetan plateaus, and have been well adjusted to high altitude. Arterial blood samples taken at 4100 m of elevation in acclimatized rats and adapted pikas revealed inter-species differences with lower hemoglobin and hematocrit and higher blood pH in pikas. A linear and significant increase in minute ventilation was observed in pikas, which help them to cope with hypoxic-hypercapnia. Pikas also displayed a high inspiratory drive and an invariant respiratory timing regardless of the conditions. Biochemical analysis revealed that N-methyl-D-aspartate receptor (NMDA) receptor gene and nNOS gene are highly conserved between rats and pikas, however pikas have higher expression of NMDA receptors and nNOS compared to rats at the brainstem level. Taken together, these results suggest that pikas have developed a specific ventilatory pattern supported by a modification of the NMDA/NO ventilatory central pathways to survive in extreme conditions imposed on the Tibetan plateaus. These physiological adaptive strategies help in maintaining a better blood oxygenation despite high CO2 concentration in burrows at high altitude. PMID:25988712

  8. Effects of nickel, zinc, and lead-contaminated soil on burrowing rate and coelomocytes of the earthworm, Allolobophora chlorotica.

    PubMed

    Podolak, Agnieszka; Piotrowska, Elzbieta; Klimek, Malgorzata; Klimek, Beata Anna; Kruk, Jerzy; Plytycz, Barbara

    2011-01-01

    We have shown previously that stubby worms Allolobophora chlorotica are sensitive to environmental stress, including metal-polluted soil. In order to discern the mechanisms of this sensitivity, adult (clitellate) Al. chlorotica were exposed in the laboratory to soil samples soaked with water (control) or Ni (1 and 2 mg/kg), Zn (1.25 and 2.5 g/kg) or Pb (5 and 10 g/kg) chlorides. Worms avoided contact with metal contaminants by prolonging burrowing time in metal-soaked samples, especially in the case of lead. Higher concentrations of the investigated metals were lethal for worms. During a 3 week exposure to lower metal concentrations, nickel and lead readily accumulated in the bodies of worms while zinc was efficiently regulated. However, body weights and numbers of non-invasively retrieved free coelomocytes (consisting of amoebocytes and riboflavin-loaded eleocytes) were significantly lower only in zinc-exposed worms. We assume that zinc regulation in worm bodies is more energy-demanding than nickel or lead bioaccumulation, thus this might be responsible for inhibition of the body gain and diminution of immunocompetent cells in zinc-exposed earthworms. Alternatively, missing free coelomocytes may actually be involved in Zn trafficking and removal through nephridia and/or in the formation of multicellular brown bodies, since metal can unbalance host/bacteria relationships. PMID:22195460

  9. Molecular Phylogeny Supports Repeated Adaptation to Burrowing within Small-Eared Shrews Genus of Cryptotis (Eulipotyphla, Soricidae).

    PubMed

    He, Kai; Woodman, Neal; Boaglio, Sean; Roberts, Mariel; Supekar, Sunjana; Maldonado, Jesús E

    2015-01-01

    Small-eared shrews of the New World genus Cryptotis (Eulipotyphla, Soricidae) comprise at least 42 species that traditionally have been partitioned among four or more species groups based on morphological characters. The Cryptotis mexicana species group is of particular interest, because its member species inhibit a subtly graded series of forelimb adaptations that appear to correspond to locomotory behaviors that range from more ambulatory to more fossorial. Unfortunately, the evolutionary relationships both among species in the C. mexicana group and among the species groups remain unclear. To better understand the phylogeny of this group of shrews, we sequenced two mitochondrial and two nuclear genes. To help interpret the pattern and direction of morphological changes, we also generated a matrix of morphological characters focused on the evolutionarily plastic humerus. We found significant discordant between the resulting molecular and morphological trees, suggesting considerable convergence in the evolution of the humerus. Our results indicate that adaptations for increased burrowing ability evolved repeatedly within the genus Cryptotis. PMID:26489020

  10. Burrowing mayflies as indicators of ecosystem health: Status of populations in western Lake Erie, Saginaw Bay and Green Bay

    USGS Publications Warehouse

    Edsall, T.A.; Bur, M.T.; Gorman, O.T.; Schaeffer, J.S.

    2005-01-01

    The U.S. Environmental Protection Agency and Environment Canada are supporting the development of indicators of ecosystem health that can be used to report on progress in restoring and maintaining the Great Lakes ecosystem, as called for in the Great Lakes Water Quality Agreement between the United States and Canada. One indicator under development is based on burrowing mayflies (Hexagenia: Ephemeroptera: Ephemeridae). We sampled in western Lake Erie, Saginaw Bay (Lake Huron), and Green Bay (Lake Michigan) in spring 2001 at 117 stations covering about 1,870 km2 of lake bed, to determine the status of nymphal populations of Hexagenia, and to provide information that would further the technical development of an indicator of ecosystem health based on Hexagenia. In western Lake Erie, density and biomass of nymphs were generally highest on fine-grained substrate in offshore waters and were lower on coarser substrates in near shore waters. Nymphs were virtually absent from Saginaw Bay, where only one nymph was collected at 28 stations. Nymphs were collected at only 6 of 48 stations in Green Bay, and density and biomass were highest at the northern end of the bay. Polluted sediments are likely responsible for the absence or low density and biomass of nymphs observed on fine-grained substrates in western Lake Erie, Saginaw Bay, and Green Bay, all of which historically supported abundant populations.

  11. Parallel and Space-Efficient Construction of Burrows-Wheeler Transform and Suffix Array for Big Genome Data.

    PubMed

    Liu, Yongchao; Hankeln, Thomas; Schmidt, Bertil

    2016-01-01

    Next-generation sequencing technologies have led to the sequencing of more and more genomes, propelling related research into the era of big data. In this paper, we present ParaBWT, a parallelized Burrows-Wheeler transform (BWT) and suffix array construction algorithm for big genome data. In ParaBWT, we have investigated a progressive construction approach to constructing the BWT of single genome sequences in linear space complexity, but with a small constant factor. This approach has been further parallelized using multi-threading based on a master-slave coprocessing model. After gaining the BWT, the suffix array is constructed in a memory-efficient manner. The performance of ParaBWT has been evaluated using two sequences generated from two human genome assemblies: the Ensembl Homo sapiens assembly and the human reference genome. Our performance comparison to FMD-index and Bwt-disk reveals that on 12 CPU cores, ParaBWT runs up to 2.2× faster than FMD-index and up to 99.0× faster than Bwt-disk. BWT construction algorithms for very long genomic sequences are time consuming and (due to their incremental nature) inherently difficult to parallelize. Thus, their parallelization is challenging and even relatively small speedups like the ones of our method over FMD-index are of high importance to research. ParaBWT is written in C++, and is freely available at http://parabwt.sourceforge.net. PMID:27295644

  12. Chemotaxis of Caenorhabditis elegans in complex media: crawling, burrowing, 2D and 3D swimming, and controlled fluctuations hypothesis

    NASA Astrophysics Data System (ADS)

    Patel, Amar; Bilbao, Alejandro; Rahman, Mizanur; Vanapalli, Siva; Blawzdziewicz, Jerzy

    Caenorhabditis elegans is a powerful genetic model, essential for studies in diverse areas ranging from behavior to neuroscience to aging, and locomotion and chemotaxis are the two key observables used. We combine our recently developed theory of nematode locomotion and turning maneuvers [Phys. Fluids 25, 081902 (2013)] with simple models of chemosensation to analyze nematode chemotaxis strategies in 2D and 3D environments. We show that the sharp-turn (pirouette) chemotaxis mechanism is efficient in diverse media; in particular, the nematode does not need to adjust the sensing or motion-control parameters to efficiently chemotax in 2D crawling, 3D burrowing, and 2D or 3D swimming. In contrast, the graduate-turn mechanism becomes inefficient in swimming, unless a phase-shift is introduced between the sensing signal and modulation of body wave to generate the gradual turn. We hypothesize that there exists a new ``controlled fluctuations'' chemotaxis mechanism, in which the nematode changes the intensity of undulation fluctuations to adjust the persistence length of the trajectory in response to a variation in chemoattractant concentration. Supported by NSF Grant No. CBET 1059745.

  13. Lung Volume Recruitment in Multiple Sclerosis

    PubMed Central

    Srour, Nadim; LeBlanc, Carole; King, Judy; McKim, Douglas A.

    2013-01-01

    Introduction Pulmonary function abnormalities have been described in multiple sclerosis including reductions in forced vital capacity (FVC) and cough but the time course of this impairment is unknown. Peak cough flow (PCF) is an important parameter for patients with respiratory muscle weakness and a reduced PCF has a direct impact on airway clearance and may therefore increase the risk of respiratory tract infections. Lung volume recruitment is a technique that improves PCF by inflating the lungs to their maximal insufflation capacity. Objectives Our goals were to describe the rate of decline of pulmonary function and PCF in patients with multiple sclerosis and describe the use of lung volume recruitment in this population. Methods We reviewed all patients with multiple sclerosis referred to a respiratory neuromuscular rehabilitation clinic from February 1999 until December 2010. Lung volume recruitment was attempted in patients with FVC <80% predicted. Regular twice daily lung volume recruitment was prescribed if it resulted in a significant improvement in the laboratory. Results There were 79 patients included, 35 of whom were seen more than once. A baseline FVC <80% predicted was present in 82% of patients and 80% of patients had a PCF insufficient for airway clearance. There was a significant decline in FVC (122.6 mL/y, 95% CI 54.9–190.3) and PCF (192 mL/s/y, 95% 72–311) over a median follow-up time of 13.4 months. Lung volume recruitment was associated with a slower decline in FVC (p<0.0001) and PCF (p = 0.042). Conclusion Pulmonary function and cough decline significantly over time in selected patients with multiple sclerosis and lung volume recruitment is associated with a slower rate of decline in lung function and peak cough flow. Given design limitations, additional studies are needed to assess the role of lung volume recruitment in patients with multiple sclerosis. PMID:23383293

  14. Scorpion speciation in the Holy Land: Multilocus phylogeography corroborates diagnostic differences in morphology and burrowing behavior among Scorpio subspecies and justifies recognition as phylogenetic, ecological and biological species.

    PubMed

    Talal, Stav; Tesler, Itay; Sivan, Jaim; Ben-Shlomo, Rachel; Muhammad Tahir, H; Prendini, Lorenzo; Snir, Sagi; Gefen, Eran

    2015-10-01

    Scorpio Linnaeus, 1758 (family Scorpionidae Latreille, 1802) was considered monotypic for over a century, and comprised a single species, Scorpio maurus Linnaeus, 1758, with 19 subspecies, distributed from West Africa, throughout the Maghreb and the Middle East, to Iran. Two parapatric subspecies, Scorpio maurus fuscus (Ehrenberg, 1829) and Scorpio maurus palmatus (Ehrenberg, 1828), have long been recognized in the eastern Mediterranean region. We examined morphological variation, burrow architecture and genetic divergence among 39 populations across the distribution of the two subspecies to assess whether they are conspecific and, if not, how many species might be involved. Cuticle coloration, pedipalp chela digital carina condition, and selected measurements were recorded. Sixty burrows were excavated and examined for burrow structure and depth. A multilocus dataset comprising concatenated fragments of one nuclear (28S rDNA) and three mitochondrial (12S rDNA, 16S rDNA, Cytochrome c Oxidase Subunit I) loci, totaling ca. 2400 base-pairs, was produced for 41 individuals, and a single-locus dataset comprising 658 base-pairs of the COI locus for 156 individuals. Despite overlapping ranges in morphometric characters of pedipalp chela shape, the putative subspecies were easily distinguished by cuticle coloration and condition of the pedipalp chela digital carina, and were also found to differ significantly in burrow architecture and depth. Phylogeographical analyses of the COI and multilocus datasets recovered seven distinct clades. Separate analyses of mitochondrial sequences, and combined analyses of mitochondrial and nuclear sequences support most clades. The two major clades corresponded with the geographical distributions of S. m. fuscus and S. m. palmatus in the region. Specimens from these clades were genetically distinct, and exhibited different burrow structure in geographically-proximate localities, suggesting reproductive isolation. The palmatus clade

  15. Recruitment variability of alewives in Lake Michigan

    USGS Publications Warehouse

    Madenjian, C.P.; Hook, T.O.; Rutherford, E.S.; Mason, D.M.; Croley, T.E., II; Szalai, E.B.; Bence, J.R.

    2005-01-01

    We used a long-term series of observations on alewife Alosa pseudoharengus abundance that was based on fall bottom-trawl catches to assess the importance of various abiotic and biotic factors on alewife recruitment in Lake Michigan during 1962–2002. We first fit a basic Ricker spawner–recruit model to the lakewide biomass estimates of age-3 recruits and the corresponding spawning stock size; we then fit models for all possible combinations of the following four external variables added to the basic model: an index of salmonine predation on an alewife year-class, an index for the spring–summer water temperatures experienced by alewives during their first year in the lake, an index of the severity of the first winter experienced by alewives in the lake, and an index of lake productivity during an alewife year-class's second year in the lake. Based on an information criterion, the best model for alewife recruitment included indices of salmonine predation and spring–summer water temperatures as external variables. Our analysis corroborated the contention that a decline in alewife abundance during the 1970s and early 1980s in Lake Michigan was driven by salmonine predation. Furthermore, our findings indicated that the extraordinarily warm water temperatures during the spring and summer of 1998 probably led to a moderately high recruitment of age-3 alewives in 2001, despite abundant salmonines.

  16. Rethinking Recruitment: The Comprehensive and Strategic Recruitment of Secondary Science Teachers

    ERIC Educational Resources Information Center

    Luft, Julie A.; Wong, Sissy S.; Semken, Steve

    2011-01-01

    The shortage of science teachers has spurred a discussion about their retention and recruitment. While discussion about retaining science teachers has increased dramatically in just the last few years, science teacher educators have not attended to the recruitment of science teachers with the same tenacity. This paper is our effort to initiate…

  17. Recruiting as much about families as candidate

    SciTech Connect

    Madison, Alison L.

    2011-06-05

    Monthly economic diversity column for Tri-City Herald: For businesses large and small, one of the biggest challenges to staying afloat and achieving growth is attracting and retaining key talent. And in an area such as the Tri-Cities, where many of our skilled professionals are geographical transplants and the technology-based economic growth we seek often requires highly specific skill sets, effective recruiting is especially critical. But it isn’t just about matching candidates with open positions and signing on the dotted line. In fact, members of the Three Rivers Entrepreneur Network were reminded at a recent presentation that recruiting is very much about attracting the family unit.

  18. Computational social network modeling of terrorist recruitment.

    SciTech Connect

    Berry, Nina M.; Turnley, Jessica Glicken; Smrcka, Julianne D.; Ko, Teresa H.; Moy, Timothy David; Wu, Benjamin C.

    2004-10-01

    The Seldon terrorist model represents a multi-disciplinary approach to developing organization software for the study of terrorist recruitment and group formation. The need to incorporate aspects of social science added a significant contribution to the vision of the resulting Seldon toolkit. The unique addition of and abstract agent category provided a means for capturing social concepts like cliques, mosque, etc. in a manner that represents their social conceptualization and not simply as a physical or economical institution. This paper provides an overview of the Seldon terrorist model developed to study the formation of cliques, which are used as the major recruitment entity for terrorist organizations.

  19. Haemodynamic Effects of Lung Recruitment Manoeuvres

    PubMed Central

    Szakmány, Tamás

    2015-01-01

    Atelectasis caused by lung injury leads to increased intrapulmonary shunt, venous admixture, and hypoxaemia. Lung recruitment manoeuvres aim to quickly reverse this scenario by applying increased airway pressures for a short period of time which meant to open the collapsed alveoli. Although the procedure can improve oxygenation, but due to the heart-lung and right and left ventricle interactions elevated intrathoracic pressures can inflict serious effects on the cardiovascular system. The purpose of this paper is to give an overview on the pathophysiological background of the heart-lung interactions and the best way to monitor these changes during lung recruitment. PMID:26682219

  20. Selection and Training of Navy Recruit Company Commanders. Final Report.

    ERIC Educational Resources Information Center

    Curry, Thomas F., Jr.; And Others

    This report addresses the selection, training, and utilization of Navy Recruit Company Commanders (Recruit Training Instructors). It represents one in a series of reports concerning the optimization of Navy Recruit Training to meet the needs of the post-1980 period. The report provides a comprehensive review of the Navy's Recruit Company Commander…

  1. 20 CFR 655.154 - Additional positive recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Additional positive recruitment. 655.154... recruitment. (a) Where to conduct additional positive recruitment. The employer must conduct positive recruitment within a multistate region of traditional or expected labor supply where the CO finds that...

  2. Veterans' Preference: A Barrier to the Recruitment of Women?

    ERIC Educational Resources Information Center

    Kennedy, R. Bryan

    1988-01-01

    Examined recruitment data for the United States Missile Command from years 1978-1984 to ascertain whether or not the Veterans' Readjustment Program presented a barrier to recruitment of women. Found adverse effects on recruitment of women, noting recruitment efforts successful with one population may present barriers to another. (Author/ABL)

  3. 28 CFR 92.8 - Providing recruitment services.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... POLICING SERVICES (COPS) Police Recruitment Program Guidelines § 92.8 Providing recruitment services. The... populations to a police department. The recruitment strategies employed may include: (a) A process for recruiting applicants for employment by a police department. These processes should include working...

  4. 28 CFR 92.8 - Providing recruitment services.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... POLICING SERVICES (COPS) Police Recruitment Program Guidelines § 92.8 Providing recruitment services. The... populations to a police department. The recruitment strategies employed may include: (a) A process for recruiting applicants for employment by a police department. These processes should include working...

  5. 28 CFR 92.8 - Providing recruitment services.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... POLICING SERVICES (COPS) Police Recruitment Program Guidelines § 92.8 Providing recruitment services. The... populations to a police department. The recruitment strategies employed may include: (a) A process for recruiting applicants for employment by a police department. These processes should include working...

  6. 28 CFR 92.8 - Providing recruitment services.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... POLICING SERVICES (COPS) Police Recruitment Program Guidelines § 92.8 Providing recruitment services. The... populations to a police department. The recruitment strategies employed may include: (a) A process for recruiting applicants for employment by a police department. These processes should include working...

  7. Oxygen and carbon dioxide fluctuations in burrows of subterranean blind mole rats indicate tolerance to hypoxic-hypercapnic stresses.

    PubMed

    Shams, Imad; Avivi, Aaron; Nevo, Eviatar

    2005-11-01

    The composition of oxygen (O2), carbon dioxide (CO2), and soil humidity in the underground burrows from three species of the Israeli subterranean mole rat Spalax ehrenbergi superspecies were studied in their natural habitat. Two geographically close populations of each species from contrasting soil types were probed. Maximal CO2 levels (6.1%) and minimal O2 levels (7.2%) were recorded in northern Israel in the breeding mounds of S. carmeli in a flooded, poor drained field of heavy clay soil with very high volumetric water content. The patterns of gas fluctuations during the measurement period among the different Spalax species studied were similar. The more significant differentiation in gas levels was not among species, but between neighboring populations inhabiting heavy soils or light soils: O2 was lower and CO2 was higher in the heavy soils (clay and basaltic) compared to the relatively light soils (terra rossa and rendzina). The extreme values of gas concentration, which occurred during the rainy season, seemed to fluctuate with partial flooding of the tunnels, animal digging activity, and over-crowded breeding mounds inhabited by a nursing female and her offspring. The gas composition and soil water content in neighboring sites with different soil types indicated large differences in the levels of hypoxic-hypercapnic stress in different populations of the same species. A growing number of genes associated with hypoxic stress have been shown to exhibit structural and functional differences between the subterranean Spalax and the above-ground rat (Rattus norvegicus), probably reflecting the molecular adaptations that Spalax went through during 40 million years of evolution to survive efficiently in the severe fluctuations in gas composition in the underground habitat. PMID:16223592

  8. Recruiting the Next Generation of School Librarians

    ERIC Educational Resources Information Center

    Bishop, Kay; Janczak, Sue

    2007-01-01

    In 2003 at the American Association of School Librarians (AASL) 11th National Conference in Kansas City, the AASL Task Force on Recruitment for the Profession noted that 68 percent of school librarians will retire by the year 2015. They also reported extremely severe shortages of school librarians in ten states and severe shortages in 30 states…

  9. 29 CFR 36.510 - Recruitment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or... not discriminate on the basis of sex in the recruitment and hiring of employees. Where a recipient...

  10. Internship: A Recruitment and Selection Perspective

    ERIC Educational Resources Information Center

    Zhao, Hao; Liden, Robert C.

    2011-01-01

    In this study, we examined internship as a recruitment and selection process. On the basis of impression management theory, we hypothesized that both organizations and interns make efforts to impress the other party during the internship if they intend to hire or be hired. Using longitudinal data collected at 3 points from 122 intern-supervisor…

  11. Discrimination in Recruitment: An Empirical Analysis.

    ERIC Educational Resources Information Center

    Newman, Jerry M.

    1978-01-01

    To investigate whether recruitment practices of companies with affirmative action programs discriminated against Blacks or resulted in reverse discrimination, qualifications and race of fictitious job applicants were manipulated on resumes sent to a sample of employers. Responses strongly indicate discrimination, with Black applicants favored…

  12. Implicit Assumptions in High Potentials Recruitment

    ERIC Educational Resources Information Center

    Posthumus, Jan; Bozer, Gil; Santora, Joseph C.

    2016-01-01

    Purpose: Professionals of human resources (HR) use different criteria in practice than they verbalize. Thus, the aim of this research was to identify the implicit criteria used for the selection of high-potential employees in recruitment and development settings in the pharmaceutical industry. Design/methodology/approach: A semi-structured…

  13. 40 CFR 5.510 - Recruitment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex...) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  14. 40 CFR 5.510 - Recruitment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 5.510 Recruitment....

  15. Reaching Out: Recruiting a Specialized Ethnic Population.

    ERIC Educational Resources Information Center

    Lycoming County Library System, Williamsport, PA.

    This report describes a project intended to address specialized recruitment of a multiethnic drug and alcohol recovery population in Lycoming County, Pennsylvania, who had not availed themselves of adult literacy services. A collaborator would be established within the community to encourage educationally disadvantaged adults who would be…

  16. Teacher Education Recruitment: A Comprehensive Marketing Approach.

    ERIC Educational Resources Information Center

    Didham, Cheryl K.; Kortokrax-Clark, Deborah

    Due to a declining enrollment and a predicted teacher shortage, a specific student recruitment plan was implemented at Bowling Green State University (BGSU) in Ohio. This helped foster a 26 percent increase in teacher education enrollment. With the understanding that an institution must find out what its public expects and what their perceptions…

  17. Research Guides Mayo Clinic's Recruitment, Retention Efforts.

    ERIC Educational Resources Information Center

    Nayar, Veena R.; Morrey, Michael A.; Schneider, Kenneth J.; Purrington, Anne W.; Wilshusen, Laurie L.; Mullen, Michael P.; Seltman, Kent D.

    2001-01-01

    Discusses a collaborative study between Mayo Clinic's departments of human resources and marketing to identify the factors that influence candidates' decisions to accept or decline job offers and the reasons behind staff resignations. Study aimed to increase the effectiveness of employee recruitment advertising, streamline its interviewing…

  18. 18 CFR 1317.510 - Recruitment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Recruitment. 1317.510... THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited §...

  19. 18 CFR 1317.510 - Recruitment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Recruitment. 1317.510... THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited §...

  20. 18 CFR 1317.510 - Recruitment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Recruitment. 1317.510... THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited §...

  1. 18 CFR 1317.510 - Recruitment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Recruitment. 1317.510... THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited §...

  2. 1978-79 Recruitment & Retention Program.

    ERIC Educational Resources Information Center

    DeCosmo, Richard

    The Moraine Valley Community College (MVCC) 1978-79 Recruitment Program seeks to increase the pool of students who wish to attend college rather than compete more aggressively for those students who have already decided to participate in higher education. A special adjunct Retention Program has been developed to enhance the entire recruitment…

  3. The 1994 College Relations and Recruitment Survey.

    ERIC Educational Resources Information Center

    Journal of Career Planning & Employment, 1995

    1995-01-01

    Presents results of a survey by the National Association of Colleges and Employers of its employer members. Responding organizations (n=422) rated on-campus recruitment as the most effective method of attracting college graduates. General trends are analyzed in terms of diversity, downsizing, company growth, competition, and selectivity. (JPS)

  4. Providence Sponsors Diocesan Teacher Recruiting Campaign.

    ERIC Educational Resources Information Center

    Dygert, William

    2001-01-01

    Addresses the issue of teacher recruitment in Providence, Rhode Island. Explains that the Catholic education staff designed a campaign that involved creating marketing materials, advertising in daily newspapers, and holding job fairs and open houses. Stresses the importance of promoting teaching at Catholic schools as both rewarding and…

  5. Recruitment and Retention in Youth Development Programming

    ERIC Educational Resources Information Center

    Anderson-Butcher, Dawn

    2005-01-01

    Youth development programs are designed to ensure that young people experience healthy development, success in school, and smooth transitions to adulthood. However, ensuring that adolescents participate in these programs is a continual challenge, especially as they age. Exploring key issues related to recruiting and retaining involvement in youth…

  6. Factors Influencing Career Choice among Police Recruits

    ERIC Educational Resources Information Center

    Cole, Bryan

    2012-01-01

    This quantitative, non-experimental study examined the career choice factors of 154 (n = 154) police recruits to determine a correlation of age group generation to the five career choice factors presented in the Sibson Reward of Work Model. Law enforcement agencies faced a shortage of viable candidates to fill vacant positions. While extensive…

  7. 40 CFR 5.510 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex...) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  8. 22 CFR 146.310 - Recruitment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Relations DEPARTMENT OF STATE CIVIL RIGHTS NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and....300 through 146.310 apply shall not discriminate on the basis of sex in the recruitment and...

  9. 20 CFR 655.205 - Recruitment period.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 3 2013-04-01 2013-04-01 false Recruitment period. 655.205 Section 655.205 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR TEMPORARY EMPLOYMENT OF FOREIGN WORKERS IN THE UNITED STATES Labor Certification Process for Logging Employment and...

  10. 22 CFR 229.510 - Recruitment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Recruitment. 229.510 Section 229.510 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in...

  11. 22 CFR 229.510 - Recruitment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Recruitment. 229.510 Section 229.510 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in...

  12. 22 CFR 229.510 - Recruitment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Recruitment. 229.510 Section 229.510 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in...

  13. 22 CFR 229.510 - Recruitment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Recruitment. 229.510 Section 229.510 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in...

  14. Recruiting Participants for Randomized Controlled Trials

    ERIC Educational Resources Information Center

    Gallagher, H. Alix; Roschelle, Jeremy; Feng, Mingyu

    2014-01-01

    The objective of this study was to look across strategies used in a wide range of studies to build a framework for researchers to use in conceptualizing the recruitment process. This paper harvests lessons learned across 19 randomized controlled trials in K-12 school settings conducted by a leading research organization to identify strategies that…

  15. 20 CFR 655.30 - Supervised recruitment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Supervised recruitment. 655.30 Section 655.30 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR TEMPORARY EMPLOYMENT OF FOREIGN WORKERS IN THE UNITED STATES Labor Certification Process and Enforcement of Attestations for Temporary Employment in Occupations...

  16. The Right Time for Recruiting New Colleagues

    ERIC Educational Resources Information Center

    Tiala, Sylvia; Harris, Kara

    2011-01-01

    Exciting times lie ahead for technology and engineering educators as the profession debates its role relative to national STEM initiatives, legislation is introduced to expand engineering/technology education into the K-12 curriculum, and a national assessment for technological literacy is developed. The time is right to recruit new technology…

  17. Computational social dynamic modeling of group recruitment.

    SciTech Connect

    Berry, Nina M.; Lee, Marinna; Pickett, Marc; Turnley, Jessica Glicken; Smrcka, Julianne D.; Ko, Teresa H.; Moy, Timothy David; Wu, Benjamin C.

    2004-01-01

    The Seldon software toolkit combines concepts from agent-based modeling and social science to create a computationally social dynamic model for group recruitment. The underlying recruitment model is based on a unique three-level hybrid agent-based architecture that contains simple agents (level one), abstract agents (level two), and cognitive agents (level three). This uniqueness of this architecture begins with abstract agents that permit the model to include social concepts (gang) or institutional concepts (school) into a typical software simulation environment. The future addition of cognitive agents to the recruitment model will provide a unique entity that does not exist in any agent-based modeling toolkits to date. We use social networks to provide an integrated mesh within and between the different levels. This Java based toolkit is used to analyze different social concepts based on initialization input from the user. The input alters a set of parameters used to influence the values associated with the simple agents, abstract agents, and the interactions (simple agent-simple agent or simple agent-abstract agent) between these entities. The results of phase-1 Seldon toolkit provide insight into how certain social concepts apply to different scenario development for inner city gang recruitment.

  18. Recruiting and Advising Challenges in Actuarial Science

    ERIC Educational Resources Information Center

    Case, Bettye Anne; Guan, Yuanying Michelle; Paris, Stephen

    2014-01-01

    Some challenges to increasing actuarial science program size through recruiting broadly among potential students are identified. Possible solutions depend on the structures and culture of the school. Up to three student cohorts may result from partition of potential students by the levels of academic progress before program entry: students…

  19. 49 CFR 25.510 - Recruitment.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Office of the Secretary of Transportation NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in... hiring. A recipient shall not discriminate on the basis of sex in the recruitment and hiring of...

  20. 45 CFR 86.23 - Recruitment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Department of Health and Human Services GENERAL ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... recipient to which this subpart applies shall not discriminate on the basis of sex in the recruitment...