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Sample records for stick-nest rat middens

  1. Age estimates and stick-nest rat middens

    International Nuclear Information System (INIS)

    Pearson, S.; Lawson, E.

    1998-01-01

    A total of 112 radiocarbon analyses on stick-nest rat middens gathered from published and grey literature show (see figure) that the middens of stick-nest rats have a positively skewed distribution. The average of all the estimates is ca. 2967 BP with the oldest midden dated at around 10870 BP. Over 75% of the results are younger than -4480 BP. Possible explanations for this pattern include; sample bias, rate of midden and cave decay, a real pattern of midden age distribution and development of techniques. The components of the midden being used for radiocarbon analysis has been remarkably uniform. This reflects the small number of researchers in the field and the experience of the American packrat midden research. Early researchers using conventional methods used charcoal and large mixtures of material whereas AMS now allows individual scats to be analysed. In fact 37% of analyses have been on scats as these provide direct evidence of midden occupation and are plentiful in the midden matrix. 66% of analyses used AINSE's AMS method and 23% used conventional methods - the distribution of results using the two methods are similar. A number of dates have incomplete laboratory or methods information. Similar analysis of packrat midden dates in the United States identified both ecological and systematic bias in the age patterns (Webb 1986). The efficacy of midden analysis in Australia, as in America, is limited by the cost of age estimates

  2. Palaeo-poo: date from rat scats

    International Nuclear Information System (INIS)

    Pearson, S.; Department of Geography.

    1997-01-01

    AMS dating has allowed a detailed study of the stratigraphy of stick-nest rat (Leporillus spp.) middens. The results of multiple dates on apparently the same layers of the middens show that the taphonomy of the midden is complex. Nevertheless, the information recovered from this source is an exciting addition to understanding arid ecosystems. Information about the local and regional vegetation, possible CO 2 -induced changes in stomata, distribution of mammals and their predator-prey relations has been recovered from the middens. Palaeoecological information coming from the arid zone has been limited but this source provides a breakthrough in providing direct and detailed ecological information. This helps contextualise the late Holocene increase in arid zone archaeological site visibility. It emphasises the pattern of arid zone mammal losses. It provides important corroborating evidence to other palaeoecological records. It is emphasised that the deposits containing pollen and macrofossils are datable using radiocarbon but there are some serious problems in providing ecological information from stick-nest rat middens

  3. Red squirrel middens influence abundance but not diversity of other vertebrates.

    Directory of Open Access Journals (Sweden)

    Erin E Posthumus

    Full Text Available Some animals modify the environment in ways that can influence the resources available to other species. Because red squirrels (Tamiasciurus hudsonicus create large piles of conifer-cone debris (middens in which they store cones, squirrels concentrate resources that might affect biodiversity locally. To determine whether other animals are attracted to midden sites beyond their affinity for the same resources that attract red squirrels, we assessed associations between middens, mammals, and birds at population and community levels. We surveyed 75 middens where residency rates of red squirrels varied during the previous five years; sampling along this residency gradient permitted us to evaluate the influence of resources at middens beyond the influence of a resident squirrel. At each location, we quantified vegetation, landscape structure, abundance of conifer cones, and midden structure, and used capture-recapture, distance sampling, and remote cameras to quantify presence, abundance, and species richness of mammals and birds. Red squirrels and the resources they concentrated at middens influenced mammals and birds at the population scale and to a lesser extent at the community scale. At middens with higher residency rates of red squirrels, richness of medium and large mammals increased markedly and species richness of birds increased slightly. After accounting for local forest characteristics, however, only species richness of medium-to-large mammals was associated with a red squirrel being resident during surveys. In areas where red squirrels were resident during surveys or in areas with greater amounts of resources concentrated by red squirrels, abundances of two of four small mammal species and two of four bird species increased. We conclude that the presence of this ecosystem modifier and the resources it concentrates influence abundance of some mammals and birds, which may have implications for maintaining biodiversity across the wide

  4. Life Amongst the Rubbish: Middening and Conspicuous Consumption at Durrington Walls

    Directory of Open Access Journals (Sweden)

    Ben Chan

    2009-09-01

    Full Text Available Recent excavations at Durrington Walls have revealed a series of archaeological remains unparalleled in southern Britain. The most artefact-rich part of the site lies just outside the eastern entrance to the henge where a series of five houses was discovered flanking the Durrington Avenue. These houses were surrounded by a large midden that comprised a massive quantity of animal bone, pottery and worked flint. The number of articulated animal bones within the midden is suggestive of large-scale and 'wasteful' feasting episodes. This article presents the preliminary analysis of the worked stone from the midden. Durrington Walls represents a site of massive consumption: consumption of labour, wood, meat, pottery and worked stone. The material from the midden will be understood in these terms, as an act of massive, final and conspicuous consumption.

  5. Molecular analysis of a 11 700-year-old rodent midden from the Atacama Desert, Chile

    Science.gov (United States)

    Kuch, M.; Rohland, N.; Betancourt, J.L.; Latorre, C.; Steppan, S.; Poinar, H.N.

    2002-01-01

    DNA was extracted from an 11 700-year-old rodent midden from the Atacama Desert, Chile and the chloroplast and animal mitochondrial DNA (mtDNA) gene sequences were analysed to investigate the floral environment surrounding the midden, and the identity of the midden agent. The plant sequences, together with the macroscopic identifications, suggest the presence of 13 plant families and three orders that no longer exist today at the midden locality, and thus point to a much more diverse and humid climate 11 700 years ago. The mtDNA sequences suggest the presence of at least four different vertebrates, which have been putatively identified as a camelid (vicuna), two rodents (Phyllotis and Abrocoma), and a cardinal bird (Passeriformes). To identify the midden agent, DNA was extracted from pooled faecal pellets, three small overlapping fragments of the mitochondrial cytochrome b gene were amplified and multiple clones were sequenced. These results were analysed along with complete cytochrome b sequences for several modern Phyllotis species to place the midden sequence phylogenetically. The results identified the midden agent as belonging to an ancestral P. limatus. Today, P. limatus is not found at the midden locality but it can be found 100 km to the north, indicating at least a small range shift. The more extensive sampling of modern Phyllotis reinforces the suggestion that P. limatus is recently derived from a peripheral isolate.

  6. Kleptoparasitic behavior and species richness at Mt. Graham red squirrel middens

    Science.gov (United States)

    Andrew J. Edelman; John L. Koprowski; Jennifer L. Edelman

    2005-01-01

    We used remote photography to assess the frequency of inter- and intra-specific kleptoparasitism and species richness at Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis) middens. Remote cameras and conifer cones were placed at occupied and unoccupied middens, and random sites. Species richness of small mammals was higher at red squirrel...

  7. Holocene vegetation history from fossil rodent middens near Arequipa, Peru

    Science.gov (United States)

    Holmgren, C.A.; Betancourt, J.L.; Rylander, K.A.; Roque, J.; Tovar, O.; Zeballos, H.; Linares, E.; Quade, Jay

    2001-01-01

    Rodent (Abrocoma, Lagidium, Phyllotis) middens collected from 2350 to 2750 m elevation near Arequipa, Peru (16??S), provide an ???9600-yr vegetation history of the northern Atacama Desert, based on identification of >50 species of plant macrofossils. These midden floras show considerable stability throughout the Holocene, with slightly more mesophytic plant assemblages in the middle Holocene. Unlike the southwestern United States, rodent middens of mid-Holocene age are common. In the Arequipa area, the midden record does not reflect any effects of a mid-Holocene mega drought proposed from the extreme lowstand (100 m below modern levels, >6000 to 3500 yr B.P.) of Lake Titicaca, only 200 km east of Arequipa. This is perhaps not surprising, given other evidence for wetter summers on the Pacific slope of the Andes during the middle Holocene as well as the poor correlation of summer rainfall among modern weather stations in the central AndesAtacama Desert. The apparent difference in paleoclimatic reconstructions suggests that it is premature to relate changes observed during the Holocene to changes in El Nin??o Southern Oscillation modes. ?? 2001 University of Washington.

  8. Time range for accumulation of shell middens from Higashimyo (western Japan) and Kimhae (southern Korea) by AMS radiocarbon dating

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Toshio, E-mail: nakamura@nendai.nagoya-u.ac.jp [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Matsui, Akira [National Research Institute for Cultural Properties, Nara, Nijyo-cho, Nara 630-8577 (Japan); Nishida, Iwao; Nakano, Mitsuru [Saga-City Board of Education, Sakae-machi, Saga 840-8501 (Japan); Omori, Takayuki [University Museum, University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033 (Japan)

    2013-01-15

    Numerous large and small shell middens have been reported throughout the world. An interesting question is when the huge and thick shell middens were formed, and how many years were required to build up the whole midden. Shell middens contain not only shell fragments but also organic substances such as bones, nuts, acorn, and plant residues, which are suitable substances with which to establish {sup 14}C chronology of the middens. We have conducted {sup 14}C dating on terrestrial and marine materials collected from two lowland shell middens, the Higashimyo site in Japan (the Earliest Jomon period) and the Kimhae site in Korea (the Proto-Three Kingdom period), to establish high precision {sup 14}C chronologies and determine the time required for shell accumulation. According to Bayesian analysis of {sup 14}C ages from terrestrial samples, accumulation of Midden No. 1 at Higashimyo (altitude from -1.1 to -2.3 m a.s.l., {Delta}d = 1.2 m) started at around 8050-7950 cal BP and ended at 7950-7750 cal BP, lasting for ca. 100 cal yr, while accumulation of Midden No. 2 (altitude from -0.5 to -2.0 m a.s.l., {Delta}d = 1.5 m) started at around 8050-7800 cal BP and ended at 7800-7650 cal BP, lasting for ca. 200 cal yr. Thus the Midden No. 1 was abandoned a bit earlier than Midden No. 2, but the time range for sediment accumulation overlaps each other. Accumulation at the Kimhae shell midden (altitude from 5 to 14 m a.s.l., {Delta}d = 9 m) started at around the middle of the 1st C cal BC and ended at around the middle of the 3rd C cal AD, lasting for ca. 250 to 300 cal yr.

  9. Audit Groenfonds Midden-Delfland : beoordeling uitvoering puntensysteem Groene Diensten

    NARCIS (Netherlands)

    Schotman, A.G.M.; Melman, T.C.P.

    2011-01-01

    Een aantal gemeenten in en rond Midden-Delfland heeft een fonds ingesteld om de instandhouding van het agrarisch cultuurlandschap van dit gebied te ondersteunen via een puntensysteem voor de beloning van ‘Groene Diensten’. De Europese Commissie heeft het puntensysteem getoetst en goedgekeurd. Deze

  10. Nest etiquette--where ants go when nature calls.

    Directory of Open Access Journals (Sweden)

    Tomer J Czaczkes

    Full Text Available Sanitary behaviour is an important, but seldom studied, aspect of social living. Social insects have developed several strategies for dealing with waste and faecal matter, including dumping waste outside the nest and forming specialised waste-storage chambers. In some cases waste material and faeces are put to use, either as a construction material or as a long-lasting signal, suggesting that faeces and waste may not always be dangerous. Here we examine a previously undescribed behaviour in ants - the formation of well-defined faecal patches. Lasius niger ants were housed in plaster nests and provided with coloured sucrose solution. After two months, 1-4 well defined dark patches, the colour of the sucrose solution, formed within each of the plaster nests. These patches never contained other waste material such as uneaten food items, or nestmate corpses. Such waste was collected in waste piles outside the nest. The coloured patches were thus distinct from previously described 'kitchen middens' in ants, and are best described as 'toilets'. Why faeces is not removed with other waste materials is unclear. The presence of the toilets inside the nest suggests that they may not be an important source of pathogens, and may have a beneficial role.

  11. "Meerdere Midden-Paleolithische bewoningsfasen in een loess-bodem sequentie te Veldwezelt-Hezerwater, Limburg, België"

    OpenAIRE

    Bringmans, Patrick

    2006-01-01

    Meerdere Midden-Paleolithische Bewoningsfasen in een Loess-bodem Sequ entie te Veldwezelt-Hezerwater, Limburg, België Midden de jaren ’90 van de 20ste eeuw werd er door het “Laboratorium voo r Prehistorie” aan de Katholieke Universiteit Leuven een geo-archeologis ch project opgestart om in de loess-groeves van Limburgs-Haspengouw naar sporen van de Pleistocene mens te gaan prospecteren. Uit deze prospecti es bleek, dat vooral de loess-groeve te Veldwezelt-Hezerwater de beste p erspectiev...

  12. Ospreys Use Bald Eagle Nests in Chesapeake Bay Area

    OpenAIRE

    Therres, Glenn D.; Chandler, Sheri K.

    1993-01-01

    Ospreys (Pandion haliaetus) and Bald Eagles (Haliaeetus leucocephalus) share similar breeding habitat in the Chesapeake Bay area and elsewhere. The nests of these species are similar in size and appearance. Ospreys typically build large stick nests in dead trees or on man-made structures (C.J. Henny et al. 1974, Chesapeake Sci. 15:125-133; A.F. Poole 1989, Ospreys: a natural and unnatural history, Cambridge Univ. Press, NY), while Bald Eagles usually build larger nests in live trees (P.B. Woo...

  13. Raptor nest management on power lines

    Energy Technology Data Exchange (ETDEWEB)

    Harness, R.E. [EDM International Inc., Fort Collins, CO (United States)

    2005-07-01

    Many utilities in South Africa are now implementing labor-intensive methods to combat raptor nesting on power transmission lines. Methods have typically included direct nest removal and trimming of nest materials. However, the process is often unsuccessful, and utilities are now learning to accommodate the raptor nests. This paper argued that managing nests on utility structures has solved many operational problems and has resulted in positive publicity for many line operators. Nest management options included the use of stick deflectors to prevent nest material from accumulating during initial nest construction, as well as encouraging raptors to shift their efforts to a more suitable location. Raptors will often accept alternative nesting platforms, and taller, surrogate nesting poles can be placed next to distribution line structures. Elevated platforms can also be placed on problematic distribution structures, but may result in birds coming into contact with unprotected equipment. It was concluded that a successful nest management program includes plans to make nearby lines safe for raptors and to prevent their electrocution. Providing nests with bird-friendly utility configurations can result in electric facilities enhancing wild raptor populations without impacting power reliability. 14 refs., 9 figs.

  14. Nest building in House Wrens (Troglodytes aedon) : A reexamination of male and female roles

    NARCIS (Netherlands)

    Alworth, T; Scheiber, IBR

    2000-01-01

    Nest building by House Wrens (Troglodytes aedon) has been described as occurring in two stages. Males arrive on territories before females and begin the first stage by building a stick foundation in a suitable cavity. In the second stage, females build a soft cup-like structure into the stick base.

  15. Yet More “Weeds” in the Garden: Fungal Novelties from Nests of Leaf-Cutting Ants

    Science.gov (United States)

    Augustin, Juliana O.; Groenewald, Johannes Z.; Nascimento, Robson J.; Mizubuti, Eduardo S. G.; Barreto, Robert W.; Elliot, Simon L.; Evans, Harry C.

    2013-01-01

    Background Symbiotic relationships modulate the evolution of living organisms in all levels of biological organization. A notable example of symbiosis is that of attine ants (Attini; Formicidae: Hymenoptera) and their fungal cultivars (Lepiotaceae and Pterulaceae; Agaricales: Basidiomycota). In recent years, this mutualism has emerged as a model system for studying coevolution, speciation, and multitrophic interactions. Ubiquitous in this ant-fungal symbiosis is the “weedy” fungus Escovopsis (Hypocreales: Ascomycota), known only as a mycoparasite of attine fungal gardens. Despite interest in its biology, ecology and molecular phylogeny—noting, especially, the high genetic diversity encountered—which has led to a steady flow of publications over the past decade, only two species of Escovopsis have formally been described. Methods and Results We sampled from fungal gardens and garden waste (middens) of nests of the leaf-cutting ant genus Acromyrmex in a remnant of subtropical Atlantic rainforest in Minas Gerais, Brazil. In culture, distinct morphotypes of Escovopsis sensu lato were recognized. Using both morphological and molecular analyses, three new species of Escovopsis were identified. These are described and illustrated herein—E. lentecrescens, E. microspora, and E. moelleri—together with a re-description of the genus and the type species, E. weberi. The new genus Escovopsioides is erected for a fourth morphotype. We identify, for the first time, a mechanism for horizontal transmission via middens. Conclusions The present study makes a start at assigning names and formal descriptions to these specific fungal parasites of attine nests. Based on the results of this exploratory and geographically-restricted survey, we expect there to be many more species of the genus Escovopsis and its relatives associated with nests of both the lower and higher Attini throughout their neotropical range, as suggested in previous studies. PMID:24376525

  16. Preliminary assessment of late quaternary vegetation and climate of southeastern Utah based on analyses of packrat middens

    International Nuclear Information System (INIS)

    Betancourt, J.L.; Biggar, N.

    1985-06-01

    Packrat midden sequences from two caves (elevations 1585 and 2195 m; 5200 and 7200 ft) southwest of the Abajo Mountains in southeast Utah record vegetation changes that are attributed to climatic changes occurring during the last 13,000 years. These data are useful in assessing potential future climates at proposed nuclear waste sites in the area. Paleoclimates are reconstructed by defining modern elevational analogs for the vegetation assemblages identified in the middens. Based on the midden record, a climate most extreme from the present occurred prior to approximately 10,000 years before present (BP), when mean annual temperature was probably 3 to 4C (5.5 to 7F) cooler than present. However, cooling could not have exceeded 5C (9F) at 1585 m (5200 ft). Accompanying mean annual precipitation is estimated to have been from 35 to 140% greater than at present, with rainfall concentrated in the winter months. Vegetational changes beginning approximately 10,000 years BP are attributed to increased summer and mean annual temperatures, a decreasing frequency of spring freezes, and a shift from winter- to summer-dominant rainfall. Greater effective moisture than present is inferred at both cave sites from approximately 8000 to 4000 years BP. Modern flora was present at both sites by about 2000 years BP

  17. Evaluating nest supplementation as a recovery strategy for the endangered rodents of the Florida Keys

    Science.gov (United States)

    Cove, Michael V.; Simons, Theodore R.; Gardner, Beth; Maurer, Andrew S.; O'Connell, Allan F.

    2017-01-01

    The Key Largo woodrat (Neotoma floridana smalli) and Key Largo cotton mouse (Peromyscus gossypinus allapaticola) are federally endangered subspecies endemic to the tropical hardwood hammocks of Key Largo, Florida. Woodrats are considered generalists in habitat and diet, yet a steady decline in natural stick nests and capture rates over the past several decades suggests that they are limited by the availability of nesting habitat due to habitat loss and fragmentation. The more specialized Key Largo cotton mouse appears to rely on old growth hammock, a habitat type that is rare following past land clearing. In 2004, the U.S. Fish and Wildlife Service started building supplemental nest structures to restore habitat quality and connectivity for these endangered rodents, but nest use requires evaluation. We used camera traps and occupancy models to evaluate the factors influencing woodrat and cotton mouse use of the supplemental nests. We detected woodrats at 65 and cotton mice at 175 of 284 sampled nest structures, with co-occurrence at 38 nests. Woodrat nest use followed a gradient from low nest use in the north to high nest use in the south, which might relate to the proximity of free-ranging domestic cat (Felis catus) colonies in residential developments. Cotton mouse nest use, however, was related positively to mature hammock and related negatively to disturbed areas (e.g. scarified lands). The two species occurred independently of each other. Stick-stacking behavior was observed at supplemental nests and, although it was correlated with detection of woodrats, it was not a strong predictor of their occurrence. We suggest that nest supplementation can be an important tool for species recovery as habitat quality continues to improve with succession.

  18. Nest-building behavior of Monk Parakeets and insights into potential mechanisms for reducing damage to utility poles

    Directory of Open Access Journals (Sweden)

    Kevin R. Burgio

    2014-09-01

    Full Text Available The Monk Parakeet (Myiopsitta monachus commonly uses utility poles as a substrate for building large, bulky nests. These nests often cause fires and electric power outages, creating public safety risks and increasing liability and maintenance costs for electric companies. Previous research has focused on lethal methods and chemical contraception to prevent nesting on utility poles and electrical substations. However, implementation of lethal methods has led to public protests and lawsuits, while chemical contraception may affect other than the targeted species, and must be continually reapplied for effectiveness. One non-lethal alternative, nest removal, is costly and may not be a sustainable measure if Monk Parakeet populations continue to grow. In order to identify cost-effective non-lethal solutions to problems caused by Monk Parakeet nesting, we studied their behavior as they built nests on utility poles. Monk Parakeets initiate nests by attaching sticks at the intersection of the pole and electric lines. We found that parakeets use the electric lines exclusively to gain access to the intersection of lines and pole during nest initiation, and continue to use the lines intensively throughout construction. Monk Parakeets also have more difficulty attaching sticks during the early stages of nest construction than when the nest is nearing completion. These findings suggest that intervention during the earlier stages of nest building, by excluding Monk Parakeets from electric lines adjacent to poles, may be an effective, non-lethal method of reducing or eliminating parakeets nesting on, and damaging, utility poles.

  19. Paleo-Eskimo kitchen midden preservation in permafrost under future climate conditions at Qajaa, West Greenland

    DEFF Research Database (Denmark)

    Elberling, Bo; Matthiesen, Henning; Jørgensen, Christian Juncher

    2011-01-01

    characteristics measured in situ and from permafrost cores. Measurements of thermal properties, heat generation, oxygen consumption and CO2 production show that the kitchen midden can be characterized as peat but produces 4–7 times more heat than natural sediment. An analytical model from permafrost research has...

  20. Popsicle-Stick Cobra Wave.

    Science.gov (United States)

    Boucher, Jean-Philippe; Clanet, Christophe; Quéré, David; Chevy, Frédéric

    2017-08-25

    The cobra wave is a popular physical phenomenon arising from the explosion of a metastable grillage made of popsicle sticks. The sticks are expelled from the mesh by releasing the elastic energy stored during the weaving of the structure. Here we analyze both experimentally and theoretically the propagation of the wave front depending on the properties of the sticks and the pattern of the mesh. We show that its velocity and its shape are directly related to the recoil imparted to the structure by the expelled sticks. Finally, we show that the cobra wave can only exist for a narrow range of parameters constrained by gravity and rupture of the sticks.

  1. Public Health Knowledge Utilisation by Policy Actors: An Evaluation Study in Midden-Holland, the Netherlands

    Science.gov (United States)

    de Goede, Joyce; Steenkamer, Betty; Treurniet, Henriëtte; Putters, Kim; van Oers, Hans

    2011-01-01

    A comprehensive report has been prepared on the state of public health and healthcare in the Midden-Holland region of the Netherlands. This study describes the development of the report and the mechanisms behind public health knowledge utilisation by three groups of health policy actors: local authorities, public health professionals and regional…

  2. Comparing recent and abandoned shell middens to detect the impact of human exploitation on the intertidal ecosystem

    NARCIS (Netherlands)

    Boer, de W.F.; Pereira, T.; Guissamulo, A.

    2000-01-01

    Abandoned and recent shell middens were compared from Inhaca island, Mozambique, to investigate the impact of human exploitation. The growing human population was expected to increase the exploitation pressure, decrease the mean shell size, and increase the species diversity. Moreover,

  3. Coastal rainforest boundary dynamics during the late Holocene in monsoonal Australia: evidence from radiocarbon dates of abandoned nests of Orange-footed Scrubfowl

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, D M.J.S.; Panton, W J [Parks and Wildlife Commission of the Northern Territory, Darwin, NT (Australia); Head, J [Australian National Univ, Canberra, ACT (Australia). Quaternary Dating Research Centre

    1998-12-31

    The late Holocene history of monsoon rainforest retreat was explored by radiocarbon dating abandoned Orange-footed Scrubfowl (Megapodius reinwardt Gaimard) nests in coastal savannas in the Northern Territory of Australia. Previous work has demonstrated that in savanna environments this rainforest bird can not build nor maintain the large heaps of soil and leaf litter that it uses for nests. Excavations of two earthen mounds in a savanna habitat verified that they were abandoned Scrubfowl nests, and not Aboriginal middens, given their lack of stratigraphy, non-sequential dating of charcoal in a vertical profile, and absence of archaeological material. Radiocarbon dates of material taken from the surface of abandoned nests were determined for three sites on the coast of the Northern Territory. These analyses revealed that for all three sites, rainforests have contracted within the last 1800 years BP. On Elcho Island an abandoned nest was found to contain the land snail Xanthomelon spheroidea Le Guillou (known to prefer rainforest habitat) with a modern radiocarbon age, suggesting recent contraction of rainforest. The results of this study further weaken the theory that Aboriginal burning was a major cause of rain forest fragmentation in the monsoon tropics, and possibly elsewhere in Australia.

  4. Coastal rainforest boundary dynamics during the late Holocene in monsoonal Australia: evidence from radiocarbon dates of abandoned nests of Orange-footed Scrubfowl

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, D.M.J.S.; Panton, W.J. [Parks and Wildlife Commission of the Northern Territory, Darwin, NT (Australia); Head, J. [Australian National Univ, Canberra, ACT (Australia). Quaternary Dating Research Centre

    1997-12-31

    The late Holocene history of monsoon rainforest retreat was explored by radiocarbon dating abandoned Orange-footed Scrubfowl (Megapodius reinwardt Gaimard) nests in coastal savannas in the Northern Territory of Australia. Previous work has demonstrated that in savanna environments this rainforest bird can not build nor maintain the large heaps of soil and leaf litter that it uses for nests. Excavations of two earthen mounds in a savanna habitat verified that they were abandoned Scrubfowl nests, and not Aboriginal middens, given their lack of stratigraphy, non-sequential dating of charcoal in a vertical profile, and absence of archaeological material. Radiocarbon dates of material taken from the surface of abandoned nests were determined for three sites on the coast of the Northern Territory. These analyses revealed that for all three sites, rainforests have contracted within the last 1800 years BP. On Elcho Island an abandoned nest was found to contain the land snail Xanthomelon spheroidea Le Guillou (known to prefer rainforest habitat) with a modern radiocarbon age, suggesting recent contraction of rainforest. The results of this study further weaken the theory that Aboriginal burning was a major cause of rain forest fragmentation in the monsoon tropics, and possibly elsewhere in Australia.

  5. Establishing an anthropogenic nitrogen baseline using Native American shell middens

    Directory of Open Access Journals (Sweden)

    Autumn eOczkowski

    2016-05-01

    Full Text Available Narragansett Bay, Rhode Island, has been heavily influenced by anthropogenic nutrients for more than 200 years. Recent efforts to improve water quality have cut sewage nitrogen (N loads to this point source estuary by more than half. Given that the bay has been heavily fertilized for longer than monitoring programs have been in place, we sought additional insight into how N dynamics in the system have historically changed. To do this, we measured the N stable isotope (δ15N values in clam shells from as early as 3000 BP to the present. Samples from Native American middens were compared with those collected locally from museums, an archaeological company, and graduate student thesis projects, during a range of time periods. Overall, δ15N values in clam shells from Narragansett Bay have increased significantly over time, reflecting known patterns of anthropogenic nutrient enrichment. Pre-colonization midden shell δ15N values were significantly lower than those post-European contact. While there were no statistical differences among shells dated from the late 15th Century to 2005, there was a significant difference between 2005 and 2015 shells, which we attribute to the higher δ15N values in the effluent associated with recent sewage treatment upgrades. In contrast, the δ15N values of shells from the southern Rhode Island coast remained constant through time; while influenced by human activities, these areas are not directly influenced by point-source sewage discharge. Overall, our results show that this isotope technique for measuring δ15N values in clam shells provides useful insight into how N dynamics in coastal ecosystems have changed during thousands of years, providing managers vital historical information when setting goals for N reduction.

  6. Linking snake behavior to nest predation in a Midwestern bird community.

    Science.gov (United States)

    Weatherhead, Patrick J; Carfagno, Gerardo L F; Sperry, Jinelle H; Brawn, Jeffrey D; Robinson, Scott K

    2010-01-01

    Nest predators can adversely affect the viability of songbird populations, and their impact is exacerbated in fragmented habitats. Despite substantial research on this predator-prey interaction, however, almost all of the focus has been on the birds rather than their nest predators, thereby limiting our understanding of the factors that bring predators and nests into contact. We used radiotelemetry to document the activity of two snake species (rat snakes, Elaphe obsoleta; racers, Coluber constrictor) known to prey on nests in Midwestern bird communities and simultaneously monitored 300 songbird nests and tested the hypothesis that predation risk should increase for nests when snakes were more active and in edge habitat preferred by both snake species. Predation risk increased when rat snakes were more active, for all nests combined and for two of the six bird species for which we had sufficient nests to allow separate analyses. This result is consistent with rat snakes being more important nest predators than racers. We found no evidence, however, that nests closer to forest edges were at greater risk. These results are generally consistent with the one previous study that investigated rat snakes and nest predation simultaneously. The seemingly paradoxical failure to find higher predation risk in the snakes' preferred habitat (i.e., edge) might be explained by the snakes using edges at least in part for non-foraging activities. We propose that higher nest predation in fragmented habitats (at least that attributable to snakes) results indirectly from edges promoting larger snake populations, rather than from edges directly increasing the risk of nest predation by snakes. If so, the notion of edges per se functioning as ecological "traps" merits further study.

  7. 16 CFR 1507.10 - Rockets with sticks.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Rockets with sticks. 1507.10 Section 1507.10... FIREWORKS DEVICES § 1507.10 Rockets with sticks. Rockets with sticks (including skyrockets and bottle rockets) shall utilize a straight and rigid stick to provide a direct and stable flight. Such sticks shall...

  8. Test of the prey-base hypothesis to explain use of red squirrel midden sites by American martens

    Science.gov (United States)

    Dean E. Pearson; Leonard F. Ruggiero

    2001-01-01

    We tested the prey-base hypothesis to determine whether selection of red squirrel (Tamiasciurus hudsonicus) midden sites (cone caches) by American martens (Martes americana) for resting and denning could be attributed to greater abundance of small-mammal prey. Five years of livetrapping at 180 sampling stations in 2 drainages showed that small mammals,...

  9. Impact of prehistoric cooking practices on paleoenvironmental proxies in shell midden constituents

    Science.gov (United States)

    Müller, Peter; Staudigel, Philip; Murray, Sean T.; Westphal, Hildegard; Swart, Peter K.

    2016-04-01

    Paleoenvironmental proxy records such as oxygen isotopes of calcareous skeletal structures like fish otoliths or mollusk shells provide highest-resolution information about environmental conditions experienced by the organism. Accumulations of such skeletal structures by ancient coastal populations in so called "shell midden" deposits provide us with sub-seasonally resolved paleoclimate records covering time spans up to several millennia. Given their high temporal resolution, these deposits are increasingly used for paleoclimate reconstructions and complement our understanding of ancient climate changes. However, gathered as comestibles, most of these skeletal remains were subject to prehistoric cooking methods prior to deposition. The associated alteration of the chemical proxy signatures as well as the subsequent error for paleoenvironmental reconstructions remained almost entirely neglected so far. Here, we present clumped isotope, conventional oxygen and carbon isotopes as well as element:Ca ratios measured in modern bivalve shells after exposing them to different prehistoric cooking methods. Our data show that most cooking methods considerably alter commonly used paleoclimate proxy systems which can lead to substantial misinterpretations of ancient climate conditions. Since the magnitude of chemical alteration is not distinguishable from natural temperature variability in most coastal settings, the alteration of shell midden constituents by prehistoric cooking remains likely unnoticed in most cases. Thus, depending on the cooking method, pre-depositional heating might have introduced considerable errors into previous paleoclimate studies. However, our data also show that clumped isotope thermometry represents a suitable diagnostic tool to detect such pre-depositional cooking events and also allows differentiating between the most commonly applied prehistoric cooking methods.

  10. High-throughput sequencing of ancient plant and mammal DNA preserved in herbivore middens

    DEFF Research Database (Denmark)

    Murray, Dáithí C.; Pearson, Stuart G.; Fullagar, Richard

    2012-01-01

    DNA analysis identified unreported plant and animal taxa, some of which are locally extinct or endemic. The survival and preservation of DNA in hot, arid environments is a complex and poorly understood process that is both sporadic and rare, but the survival of DNA through desiccation may be important......The study of arid palaeoenvironments is often frustrated by the poor or non-existent preservation of plant and animal material, yet these environments are of considerable environmental importance. The analysis of pollen and macrofossils isolated from herbivore middens has been an invaluable source...

  11. Analysis of Archaeological, Geological and Historical Artifacts and Documents Pertaining to the Midden Excavation at ’Woodville’ - Unit 4, James G. Fulton, Flood Protection Project, Chartiers Creek, Pennsylvania,

    Science.gov (United States)

    1985-03-01

    Baldwin 1973:218). Another advertisement describes HALES HONEY ...as "The Great Cough Remedy For Children as well as Adults. Cures all Coughs , Colds...all recent rodent burrows which honey -combed the midden particularly in the area of the W95 transect trench. There are three major categories of...into the top of the Stratum 3j alluvium, the final natural fill in the millrace channel. Because the center of the midden was literally honey -combed

  12. Limited Nesting Stress Alters Maternal Behavior and In Vivo Intestinal Permeability in Male Wistar Pup Rats.

    Directory of Open Access Journals (Sweden)

    Nabila Moussaoui

    Full Text Available A few studies indicate that limited nesting stress (LNS alters maternal behavior and the hypothalamic pituitary adrenal (HPA axis of dams and offspring in male Sprague Dawley rats. In the present study, we evaluated the impact of LNS on maternal behavior in Wistar rats, and on the HPA axis, glycemia and in vivo intestinal permeability of male and female offspring. Intestinal permeability is known to be elevated during the first week postnatally and influenced by glucocorticoids. Dams and neonatal litters were subjected to LNS or normal nesting conditions (control from days 2 to 10 postnatally. At day 10, blood was collected from pups for determination of glucose and plasma corticosterone by enzyme immunoassay and in vivo intestinal permeability by oral gavage of fluorescein isothiocyanate-dextran 4kDa. Dams exposed to LNS compared to control showed an increase in the percentage of time spent building a nest (118%, self-grooming (69%, and putting the pups back to the nest (167%. LNS male and female pups exhibited a reduction of body weight by 5% and 4%, adrenal weights/100g body weight by 17% and 18%, corticosterone plasma levels by 64% and 62% and blood glucose by 11% and 12% respectively compared to same sex control pups. In male LNS pups, intestinal permeability was increased by 2.7-fold while no change was observed in females compared to same sex control. There was no sex difference in any of the parameters in control pups except the body weight. These data indicate that Wistar dams subjected to LNS during the first postnatal week have an altered repertoire of maternal behaviors which affects the development of the HPA axis in both sexes and intestinal barrier function in male offspring.

  13. Effects of Bufei Yishen Granules Combined with Acupoint Sticking Therapy on Pulmonary Surfactant Proteins in Chronic Obstructive Pulmonary Disease Rats

    Directory of Open Access Journals (Sweden)

    Yange Tian

    2016-01-01

    Full Text Available Our previous studies have demonstrated the beneficial effects of Bufei Yishen granules combined with acupoint sticking therapy (the integrated therapy in chronic obstructive pulmonary disease (COPD, but the underlying mechanism remains unclear. Dysfunction of pulmonary surfactant proteins (SPs, including SP-A, SP-B, SP-C, and SP-D may be included in pathophysiology of COPD. This study aimed to explore the mechanism of the integrated therapy on SPs. COPD rat models were established. The treatment groups received Bufei Yishen granules or acupoint sticking or their combination. Using aminophylline as a positive control drug. The levels of SPs in serum, BALF, and lung were measured. The results showed that the integrated therapy markedly reduced the levels of SPs in serum and increased these indicators in the lung. The integrated therapy was better than aminophylline in reducing the levels of SPs and was better than Bufei Yishen granules in reducing SP-A, SP-C, and SP-D in serum. The integrated therapy was better than aminophylline and Bufei Yishen granules in increasing SP-A, SP-B, and SP-D mRNA in the lung. SP-A and SP-D in BALF were positively correlated with PEF and EF50. The levels of SPs are associated with airway limitation. The beneficial effects of the integrated therapy may be involved in regulating pulmonary surfactant proteins.

  14. The bush Karoo rat Otomys unisulcatus on the Cape West coast ...

    African Journals Online (AJOL)

    Sticks and twigs utilized are from 10 to 517 mm long, 3,5 mm thick, and with a mean length up to 117 mm per lodge, interwoven to form intricate structures. These are criss-crossed with passages and contain two nests and two latrines each. More than 13 000 sticks can be used to build a lodge; this involves travelling total ...

  15. The popsicle-stick cobra wave

    OpenAIRE

    Boucher , Jean-Philippe; Clanet , Christophe; Quéré , David; Chevy , Frédéric

    2017-01-01

    The cobra wave is a popular physical phenomenon arising from the explosion of a metastable grillage made of popsicle sticks. The sticks are expelled from the mesh by releasing the elastic energy stored during the weaving of the structure. Here we analyse both experimentally and theoretically the propagation of the wave-front depending on the properties of the sticks and the pattern of the mesh. We show that its velocity and its shape are directly related to the recoil imparted to the structur...

  16. Ancient limpet shells as paleo-environmental and ethno-archaeological archives: the case of Beniguet Island's shell middens (Iroise Sea)

    Science.gov (United States)

    Cudennec, Jean-François; Stephan, Pierre; Dupont, Catherine; Pailler, Yvan; Thébault, Julien; Schöne, Bernd; Paulet, Yves-Marie

    2017-04-01

    During the winter 2013-2014, severe storm events caused a coastal erosion in the southern part of the Beniguet Island (Brittany, France). The associated shoreline retreat had uncovered three layers of shell middens interbedded into an aeolian sand dune deposit. From several radiocarbon dating crossed with the study of ceramic and lithic contents, the shell middens were dated to the Final Neolithic (2400 BC), the Early Bronze Age (2000 BC) and the Early Middle Age (800 AD) respectively. This site offers a unique opportunity to collect two types of information: palaeo-environmental (palaeo-temperature of sea water) and archaeological (determination of harvest season). In this study, we focus on gastropod of the genus Patella which represent 90% of the remains found in this midden. This organism is potentially a highly valuable archive for these environments because they are intertidal and relatively sedentary. We studied the growth rings in the outer calcitic layer of individual limpet shells from the Neolithic, Early Bronze Age and Present Day populations. We report here the results of δ18O analyses. We found a similarity between the reconstructed palaeo-temperature in the Neolithic and the Present periods (between 13 and 14°C in summer and about 8 - 9°C in winter). However, palaeo-temperatures of the Early Bronze Age shells are significantly lower in winter (5 - 6 °C). Moreover, the initial results of the δ18O analyses at the margin of these shells showed that they were harvested during a specific season (end of spring or early summer). Additional work will be done to address questions about shell growth dynamics of these species. These results confirm the interest of using ancient limpet shells as palaeo-environmental and archaeological archives.

  17. Computer Security: USB sticks - the silent killers

    CERN Multimedia

    Stefan Lueders, Computer Security Team

    2015-01-01

    You've just found a USB stick in Restaurant 1. You'd like to return it … but who is the owner? Maybe the contents can tell you? Connect it to your laptop, and you might figure it out. But hold on, what if its content is dangerous…?   USB sticks are an excellent vehicle for infecting countless PCs and laptops. Years ago, several dozen laptops were infected during a conference when someone passed around a USB stick with flight departure information. Unfortunately, this stick was infected. Similarly, we have seen a domino effect of infections in the FP and EN departments after some USB sticks made the rounds, infecting one PC after another. In the end, a massive number of PCs had to be reinstalled. Some USB sticks are even worse. They pretend to be “just a keyboard” (named “RubberDucky”) and, once inserted, they execute a pre-programmed sequence of keystrokes intended to extract information from your computer or take ...

  18. Stick balancing, falls and Dragon-Kings

    Science.gov (United States)

    Cabrera, J. L.; Milton, J. G.

    2012-05-01

    The extent to which the occurrence of falls, the dominant feature of human attempts to balance a stick at their fingertip, can be predicted is examined in the context of the "Dragon-King" hypothesis. For skilled stick balancers, fluctuations in the controlled variable, namely the vertical displacement angle θ, exhibit power law behaviors. When stick balancing is made less stable by either decreasing the length of the stick or by requiring the subject to balance the stick on the surface of a table tennis racket, systematic departures from the power law behaviors are observed in the range of large θ. This observation raises the possibility that the presence of departures from the power law in the large length scale region, possibly Dragon-Kings, may identify situations in which the occurrence of a fall is more imminent. However, whether or not Dragon-Kings are observed, there is a Weibull-type survival function for stick falling. The possibility that increased risk of falling can, at least to some extent, be predicted from fluctuations in the controlled variable before the event occurs has important implications for the development of preventative strategies for the management of phenomena ranging from earthquakes to epileptic seizures to falls in the elderly.

  19. Analytical approximations for stick-slip vibration amplitudes

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Fidlin, A.

    2003-01-01

    , the amplitudes, and the base frequencies of friction-induced stick¿slip and pure-slip oscillations. For stick¿slip oscillations, this is accomplished by using perturbation analysis for the finite time interval of the stick phase, which is linked to the subsequent slip phase through conditions of continuity...

  20. The "sticking period" in a maximum bench press.

    Science.gov (United States)

    van den Tillaar, Roland; Ettema, Gertjan

    2010-03-01

    The purpose of this study was to examine muscle activity and three-dimensional kinematics in the ascending phase of a successful one-repetition maximum attempt in bench press for 12 recreational weight-training athletes, with special attention to the sticking period. The sticking period was defined as the first period of deceleration of the upward movement (i.e. from the highest barbell velocity until the first local lowest barbell velocity). All participants showed a sticking period during the upward movement that started about 0.2 s after the initial upward movement, and lasted about 0.9 s. Electromyography revealed that the muscle activity of the prime movers changed significantly from the pre-sticking to the sticking and post-sticking periods. A possible mechanism for the existence of the sticking period is the diminishing potentiation of the contractile elements during the upward movement together with the limited activity of the pectoral and deltoid muscles during this period.

  1. Edible bird’s nest attenuates procoagulation effects of high-fat diet in rats

    Directory of Open Access Journals (Sweden)

    Yida Z

    2015-07-01

    Full Text Available Zhang Yida,1,2 Mustapha Umar Imam,1 Maznah Ismail,1,3 Norsharina Ismail,1 Zhiping Hou1 1Laboratory of Molecular Biomedicine, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Cardiology Department, Affiliated Hospital of Chengde Medical University, Chengde, Hebei, People’s Republic of China; 3Faculty of Medicine and Health Sciences, Department of Nutrition and Dietetics, Universiti Putra Malaysia, Serdang, Selangor, Malaysia Abstract: Edible bird’s nest (EBN is popular in Asia, and has long been used traditionally as a supplement. There are, however, limited evidence-based studies on its efficacy. EBN has been reported to improve dyslipidemia, which is closely linked to hypercoagulation states. In the present study, the effects of EBN on high-fat diet- (HFD- induced coagulation in rats were evaluated. Rats were fed for 12 weeks with HFD alone or in combination with simvastatin or EBN. Food intake was estimated, and weight measurements were made during the experimental period. After sacrifice, serum oxidized low-density lipo­protein (oxLDL, adiponectin, leptin, von willibrand factor, prostacyclin, thromboxane and lipid profile, and whole blood coagulation indices (bleeding time, prothrombin time, activated partial thromboplastin time, red blood count count, and platelet count were estimated. Furthermore, hepatic expression of coagulation-related genes was evaluated using multiplex polymerase chain reaction. The results indicated that EBN could attenuate HFD-induced hypercholesterolemia and coagulation similar to simvastatin, partly through transcriptional regulation of coagulation-related genes. The results suggested that EBN has the potential for lowering the risk of cardiovascular disease-related hypercoagulation due to hypercholesterolemia. Keywords: edible bird’s nest, coagulation, high-fat diet, hypercholesterolemia, nutrigeno­mics

  2. Leucophora Satellite Flies (Diptera: Anthomyiidae) as Nest Parasites of Sweat Bees (Hymenoptera: Halictidae) in the Neotropics.

    Science.gov (United States)

    Polidori, C; Michelsen, V; Nieves-Aldrey, J L

    2015-08-01

    The biology of the 10 species of Leucophora (Diptera: Anthomyiidae) recorded in the Neotropics remains unknown. The large majority of the studied species so far are kleptoparasites of bees and wasps. Here, we report the first observations of Leucophora andicola (Bigot) and Leucophora peullae (Malloch) visiting the nests of ground-nesting sweat bees Corynura (Hymenoptera: Halictidae) in Chilean Patagonia. Females of both species perch on small stones or sticks within a dense nest aggregation of the bees and then track pollen-loaded bees in flight with great precision, eventually following them into their nests. The overall behavior closely resembles that observed for many other species of the genus. Excavations of some bee nests returned only two dipteran puparia, possibly of Leucophora, suggesting a low parasitism rate. One male of L. peullae was also collected at the bee aggregation. This is the first report of host association for any Leucophora from the Neotropics and the first report of any anthomyiid fly associated with augochlorine bees.

  3. Edible Bird’s Nest Prevents High Fat Diet-Induced Insulin Resistance in Rats

    Directory of Open Access Journals (Sweden)

    Zhang Yida

    2015-01-01

    Full Text Available Edible bird’s nest (EBN is used traditionally in many parts of Asia to improve wellbeing, but there are limited studies on its efficacy. We explored the potential use of EBN for prevention of high fat diet- (HFD- induced insulin resistance in rats. HFD was given to rats with or without simvastatin or EBN for 12 weeks. During the intervention period, weight measurements were recorded weekly. Blood samples were collected at the end of the intervention and oral glucose tolerance test conducted, after which the rats were sacrificed and their liver and adipose tissues collected for further studies. Serum adiponectin, leptin, F2-isoprostane, insulin, and lipid profile were estimated, and homeostatic model assessment of insulin resistance computed. Effects of the different interventions on transcriptional regulation of insulin signaling genes were also evaluated. The results showed that HFD worsened metabolic indices and induced insulin resistance partly through transcriptional regulation of the insulin signaling genes. Additionally, simvastatin was able to prevent hypercholesterolemia but promoted insulin resistance similar to HFD. EBN, on the other hand, prevented the worsening of metabolic indices and transcriptional changes in insulin signaling genes due to HFD. The results suggest that EBN may be used as functional food to prevent insulin resistance.

  4. Effect of repeated fasting/refeeding on obesity development and health complications in rats arising from reduced nest.

    Science.gov (United States)

    Mozeš, Štefan; Šefčíková, Zuzana; Raček, Ľubomír

    2015-02-01

    Overnutrition during postnatal life represents a risk factor for later obesity and associated metabolic disorders. We investigated the interaction between postnatal and later-life nutrition on body composition, blood pressure and the jejunal enzyme activities in male Sprague-Dawley rats. From birth, we adjusted the number of pups in the nest to 4 (small litters-SL; overfeeding) or to 10 pups (normal litters-NL; controls), and from day 50 until 70, the SL (SL-R) and NL (NL-R) rats were subjected to 1 day fasting and 1 day refeeding cycles (RFR). Their body composition was determined by magnetic resonance imaging, and enzyme activity was assayed histochemically. At 50 and 70 days, SL rats were found to be overweight (p obesity risk. Accordingly, in these animals, efficient fat deposition and elevated blood pressure were not diminished in response to dietary restrictions in later life.

  5. Stick-slip friction and wear of articular joints

    Science.gov (United States)

    Lee, Dong Woog; Banquy, Xavier; Israelachvili, Jacob N.

    2013-01-01

    Stick-slip friction was observed in articular cartilage under certain loading and sliding conditions and systematically studied. Using the Surface Forces Apparatus, we show that stick-slip friction can induce permanent morphological changes (a change in the roughness indicative of wear/damage) in cartilage surfaces, even under mild loading and sliding conditions. The different load and speed regimes can be represented by friction maps—separating regimes of smooth and stick-slip sliding; damage generally occurs within the stick-slip regimes. Prolonged exposure of cartilage surfaces to stick-slip sliding resulted in a significant increase of surface roughness, indicative of severe morphological changes of the cartilage superficial zone. To further investigate the factors that are conducive to stick-slip and wear, we selectively digested essential components of cartilage: type II collagen, hyaluronic acid (HA), and glycosaminoglycans (GAGs). Compared with the normal cartilage, HA and GAG digestions modified the stick-slip behavior and increased surface roughness (wear) during sliding, whereas collagen digestion decreased the surface roughness. Importantly, friction forces increased up to 2, 10, and 5 times after HA, GAGs, and collagen digestion, respectively. Also, each digestion altered the friction map in different ways. Our results show that (i) wear is not directly related to the friction coefficient but (ii) more directly related to stick-slip sliding, even when present at small amplitudes, and that (iii) the different molecular components of joints work synergistically to prevent wear. Our results also suggest potential noninvasive diagnostic tools for sensing stick-slip in joints. PMID:23359687

  6. STICKING OF MOLECULES ON NONPOROUS AMORPHOUS WATER ICE

    Energy Technology Data Exchange (ETDEWEB)

    He, Jiao; Vidali, Gianfranco [Physics Department, Syracuse University, Syracuse, NY 13244 (United States); Acharyya, Kinsuk, E-mail: gvidali@syr.edu [Department of Chemistry, University of Virginia, Charlottesville, VA 22904 (United States)

    2016-05-20

    Accurate modeling of physical and chemical processes in the interstellar medium (ISM) requires detailed knowledge of how atoms and molecules adsorb on dust grains. However, the sticking coefficient, a number between 0 and 1 that measures the first step in the interaction of a particle with a surface, is usually assumed in simulations of ISM environments to be either 0.5 or 1. Here we report on the determination of the sticking coefficient of H{sub 2}, D{sub 2}, N{sub 2}, O{sub 2}, CO, CH{sub 4}, and CO{sub 2} on nonporous amorphous solid water. The sticking coefficient was measured over a wide range of surface temperatures using a highly collimated molecular beam. We showed that the standard way of measuring the sticking coefficient—the King–Wells method—leads to the underestimation of trapping events in which there is incomplete energy accommodation of the molecule on the surface. Surface scattering experiments with the use of a pulsed molecular beam are used instead to measure the sticking coefficient. Based on the values of the measured sticking coefficient, we suggest a useful general formula of the sticking coefficient as a function of grain temperature and molecule-surface binding energy. We use this formula in a simulation of ISM gas–grain chemistry to find the effect of sticking on the abundance of key molecules both on grains and in the gas phase.

  7. Effects of stick design features on perceptions of characteristics of cigarettes.

    Science.gov (United States)

    Borland, Ron; Savvas, Steven

    2013-09-01

    To examine the extent (if any) that cigarette stick dimension, tipping paper design and other decorative design/branding have on Australian smokers' perceptions of those cigarettes. An internet survey of 160 young Australian adult ever-smokers who were shown computer images of three sets of cigarette sticks--five sticks of different lengths and diameters (set A), five sticks with different tipping paper design (set B) and four sticks of different decorative design (set C). Branding was a between-subjects randomised condition for set C. For each set, respondents ranked sticks on most and least attractive, highest and lowest quality and strongest and weakest taste. Cigarette sticks were perceived as different on attractiveness, quality and strength of taste. Standard stick length/diameter was perceived as the most attractive and highest quality stick, with men more inclined to rate a slim stick as less attractive. A stick with a cork-patterned tipping paper and a gold band was seen as most attractive, of highest quality and strongest in taste compared to other tipping designs. Branded sticks were seen as more attractive, higher in quality and stronger tasting than non-branded designs, regardless of brand, although the effects were stronger for a prestige compared with a budget brand. Characteristics of the cigarette stick affect smokers' perceptions of the attributes of those cigarettes and thus are a potential means by which product differentiation can occur. A comprehensive policy to eliminate promotional aspects of cigarette design and packaging needs to include rules about stick design.

  8. Stabilizing Stick-Slip Friction

    International Nuclear Information System (INIS)

    Capozza, Rosario; Barel, Itay; Urbakh, Michael; Rubinstein, Shmuel M.; Fineberg, Jay

    2011-01-01

    Even the most regular stick-slip frictional sliding is always stochastic, with irregularity in both the intervals between slip events and the sizes of the associated stress drops. Applying small-amplitude oscillations to the shear force, we show, experimentally and theoretically, that the stick-slip periods synchronize. We further show that this phase locking is related to the inhibition of slow rupture modes which forces a transition to fast rupture, providing a possible mechanism for observed remote triggering of earthquakes. Such manipulation of collective modes may be generally relevant to extended nonlinear systems driven near to criticality.

  9. Active Sticks: a New Dimension in Controller Design

    Science.gov (United States)

    Repperger, D. W.; Mccollor, D.

    1984-01-01

    A smart stick controller was built which actively produces a force to interact with the subject's hand and to aid in tracking. When the human tracks in this situation, the man-machine system can be viewed as the combination of two closed loop feedback paths. The inner loop occurs as a result of a tactile information channel effecting the man-controller interaction through force with this stick in the active mode (the stick generates a force) and the passive mode (the stick not generating a force) are reported. The most noteworthy observation is a significant increase in apparent neuromotor bandwidth and consequently better tracking performance.

  10. Power lines, roads, and avian nest survival: effects on predator identity and predation intensity.

    Science.gov (United States)

    DeGregorio, Brett A; Weatherhead, Patrick J; Sperry, Jinelle H

    2014-05-01

    1 Anthropogenic alteration of landscapes can affect avian nest success by influencing the abundance, distribution, and behavior of predators. Understanding avian nest predation risk necessitates understanding how landscapes affect predator distribution and behavior. 2 From a sample of 463 nests of 17 songbird species, we evaluated how landscape features (distance to forest edge, unpaved roads, and power lines) influenced daily nest survival. We also used video cameras to identify nest predators at 137 nest predation events and evaluated how landscape features influenced predator identity. Finally, we determined the abundance and distribution of several of the principal predators using surveys and radiotelemetry. 3 Distance to power lines was the best predictor of predator identity: predation by brown-headed cowbirds (Molothrus ater), corvids (Corvus sp. and Cyanocitta cristata), racers (Coluber constrictor), and coachwhips (Masticophis flagellum) increased with proximity to power lines, whereas predation by rat snakes (Elaphe obsoleta) and raptors decreased. In some cases, predator density may reliably indicate nest predation risk because racers, corvids, and cowbirds frequently used power line right-of-ways. 4 Of five bird species with enough nests to analyze individually, daily nest survival of only indigo buntings (Passerina cyanea) decreased with proximity to power lines, despite predation by most predators at our site being positively associated with power lines. For all nesting species combined, distance to unpaved road was the model that most influenced daily nest survival. This pattern is likely a consequence of rat snakes, the locally dominant nest predator (28% of predation events), rarely using power lines and associated areas. Instead, rat snakes were frequently associated with road edges, indicating that not all edges are functionally similar. 5 Our results suggest that interactions between predators and landscape features are likely to be specific to

  11. Found a USB stick? Go and infect your PC!

    CERN Document Server

    Computer Security Team

    2012-01-01

    Err. Wait. Please no! USB sticks are not innocent little things. They can quickly mutate into malicious nasty beasts! Just in the recent past, at least two physics experiments were suffering as their control and data acquisition PCs, respectively, were infected by USB sticks holding malicious code. A bit longer ago, a series of laptops were infected at a 2008 computing conference as an infected USB stick made its tour around. Bad luck for those who ran a Windows operating system and inserted that stick…   So, you found a USB stick in the cafeteria? Take care. If this were a lollipop, you wouldn’t just pick it up and lick it, would you? So beware of USB sticks whose origin or previous usage you don’t know. They might infect your PC once plugged in. In order to be on the safe side, accept and share only USB sticks whose owner you trust. Run up-to-date anti-virus software on your PC, make sure that its operating system is patched...

  12. Sticking in muon catalyzed D-T fusion

    International Nuclear Information System (INIS)

    Petitjean, C.; Sherman, R.H.; Bossy, H.; Daniel, H.; Hartmann, F.J.; Neumann, W.; Schmidt, G.; Egidy, T. von

    1986-10-01

    The issue of μα sticking after muon catalyzed DT fusion is controversial, since a number of theoretical and experimental results came out recently with sticking values ω s varying over a large range. After a review of this situation, our measurements at SIN and methods of sticking analysis from neutron time structures are presented in detail. The important point is the correct understanding of the experimentally observed time distributions. At high density (liquid DT) we find, after correction for other fusion channels, for DT sticking ω s (0.45 +- 0.05)%, not dependent on tritium concentration c t and in accordance with our X-ray observations. At low density (DT gas, φ 3% - 8%) our preliminary result is 0.50 +- 0.10%, giving a ratio 1.1 +- 0.2 in agreement with conventional theories, but strongly disagreeing with the LAMPF experiment of S.E. Jones et al. Our result sets the maximum fusion output per muon to less than 220 +- 20. (author)

  13. The Existence of a Sticking Region in Free Weight Squats

    Directory of Open Access Journals (Sweden)

    Tillaar Roland van den

    2014-10-01

    Full Text Available The aim of this study was to investigate the existence of the sticking region in two legged free weight squats. Fifteen resistance-training males (age 24 ± 4 years, body mass 82 ± 11 kg, body height 179 ± 6 cm with 6 ± 3 years of resistance-training experience performed 6-RM in free weight squats. The last repetition was analyzed for the existence of a sticking region. Only in 10 out of 15 participants a sticking region was observed. The observed sticking region was much shorter than in the bench press. Furthermore, rectus femoris decreased the EMG activity in contrast to increased EMG activity in biceps femoris around the sticking and surrounding region. No significant change in EMG activity was found for the lateral and medial vastus muscles. It is suggested that a combination of these muscle activity changes could be one of the causes of the existence of the sticking region in free weight squats

  14. The existence of a sticking region in free weight squats.

    Science.gov (United States)

    van den Tillaar, Roland; Andersen, Vidar; Saeterbakken, Atle Hole

    2014-09-29

    The aim of this study was to investigate the existence of the sticking region in two legged free weight squats. Fifteen resistance-training males (age 24 ± 4 years, body mass 82 ± 11 kg, body height 179 ± 6 cm) with 6 ± 3 years of resistance-training experience performed 6-RM in free weight squats. The last repetition was analyzed for the existence of a sticking region. Only in 10 out of 15 participants a sticking region was observed. The observed sticking region was much shorter than in the bench press. Furthermore, rectus femoris decreased the EMG activity in contrast to increased EMG activity in biceps femoris around the sticking and surrounding region. No significant change in EMG activity was found for the lateral and medial vastus muscles. It is suggested that a combination of these muscle activity changes could be one of the causes of the existence of the sticking region in free weight squats.

  15. Learning control of a flight simulator stick

    NARCIS (Netherlands)

    Velthuis, W.J.R.; de Vries, Theodorus J.A.; Vrielink, Koen H.J.; Wierda, G.J.; Borghuis, André

    1998-01-01

    Aimportant part of a flight simulator is its control loading system, which is the part that emulates the behaviour of an aircraft as experienced by the pilot through the stick. Such a system consists of a model of the aircraft that is to be simulated and a stick that is driven by an electric motor.

  16. Powder properties and compaction parameters that influence punch sticking propensity of pharmaceuticals.

    Science.gov (United States)

    Paul, Shubhajit; Taylor, Lisa J; Murphy, Brendan; Krzyzaniak, Joseph F; Dawson, Neil; Mullarney, Matthew P; Meenan, Paul; Sun, Changquan Calvin

    2017-04-15

    Punch sticking is a frequently occurring problem that challenges successful tablet manufacturing. A mechanistic understanding of the punch sticking phenomenon facilitates the design of effective strategies to solve punch sticking problems of a drug. The first step in this effort is to identify process parameters and particle properties that can profoundly affect sticking performance. This work was aimed at elucidating the key material properties and compaction parameters that influence punch sticking by statistically analyzing punch sticking data of 24 chemically diverse compounds obtained using a set of tooling with removable upper punch tip. Partial least square (PLS) analysis of the data revealed that particle surface area and tablet tensile strength are the most significant factors attributed to punch sticking. Die-wall pressure, ejection force, and take-off force also correlate with sticking, but to a lesser extent. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Evolution of nesting height in an endangered Hawaiian forest bird in response to a non-native predator.

    Science.gov (United States)

    Vanderwerf, Eric A

    2012-10-01

    The majority of bird extinctions since 1800 have occurred on islands, and non-native predators have been the greatest threat to the persistence of island birds. Island endemic species often lack life-history traits and behaviors that reduce the probability of predation and they can become evolutionarily trapped if they are unable to adapt, but few studies have examined the ability of island species to respond to novel predators. The greatest threat to the persistence of the Oahu Elepaio (Chasiempis ibidis), an endangered Hawaiian forest bird, is nest predation by non-native black rats (Rattus rattus). I examined whether Oahu Elepaio nest placement has changed at the individual and population levels in response to rat predation by measuring nest height and determining whether each nest produced offspring from 1996 to 2011. Average height of Oahu Elepaio nests increased 50% over this 16-year period, from 7.9 m (SE 1.7) to 12.0 m (SE 1.1). There was no net change in height of sequential nests made by individual birds, which means individual elepaios have not learned to place nests higher. Nests ≤3 m off the ground produced offspring less often, and the proportion of such nests declined over time, which suggests that nest-building behavior has evolved through natural selection by predation. Nest success increased over time, which may increase the probability of long-term persistence of the species. Rat control may facilitate the evolution of nesting height by slowing the rate of population decline and providing time for this adaptive response to spread through the population. ©2012 Society for Conservation Biology.

  18. D'Nealian Handwriting versus Circle-Stick Print.

    Science.gov (United States)

    Thurber, Donald N.

    This paper argues against teaching children to make letters using circle-stick writing. It contends that the circle-stick method requires continued pen/pencil lifts hindering rhythm or flow in the writing process and that there is little carry-over value into cursive writing as the two scripts are totally different. D'Nealian print, one type of…

  19. Dissuasive cigarette sticks: the next step in standardised ('plain') packaging?

    Science.gov (United States)

    Hoek, Janet; Gendall, Philip; Eckert, Christine; Louviere, Jordan

    2016-11-01

    Standardised (or 'plain') packaging has reduced the appeal of smoking by removing imagery that smokers use to affiliate themselves with the brand they smoke. We examined whether changing the appearance of cigarette sticks could further denormalise smoking and enhance the negative impact of standardised packaging. We conducted an online study of 313 New Zealand smokers who comprised a Best-Worst Choice experiment and a rating task. The Best-Worst experiment used a 2×3×3×6 orthogonal design to test the following attributes: on-pack warning message, branding level, warning size and stick appearance. We identified three segments whose members' choice patterns were strongly influenced by the stick design, warning theme and size, and warning theme, respectively. Each of the dissuasive sticks tested was less preferred and rated as less appealing than the most common stick in use; a 'minutes of life lost' stick was the most aversive of the stimuli tested. Dissuasive sticks could enhance the effect of standardised packaging, particularly among older smokers who are often more heavily addicted and resistant to change. Countries introducing standardised packaging legislation should take the opportunity to denormalise the appearance of cigarette sticks, in addition to removing external tobacco branding from packs and increasing the warning size. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  20. Nutrigenomic effects of edible bird’s nest on insulin signaling in ovariectomized rats

    Directory of Open Access Journals (Sweden)

    Hou ZP

    2015-08-01

    Full Text Available Zhiping Hou,1,2 Mustapha Umar Imam,1 Maznah Ismail,1,3 Der Jiun Ooi,1 Aini Ideris,4 Rozi Mahmud5 1Laboratory of Molecular Biomedicine, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Malaysia; 2Department of Pathology, Chengde Medical University, Chengde, People’s Republic of China; 3Department of Nutrition and Dietetics, Universiti Putra Malaysia, Serdang, Malaysia; 4Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang, Malaysia; 5Department of Imaging, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia Abstract: Estrogen deficiency alters quality of life during menopause. Hormone replacement therapy has been used to improve quality of life and prevent complications, but side effects limit its use. In this study, we evaluated the use of edible bird’s nest (EBN for prevention of cardiometabolic problems in rats with ovariectomy-induced menopause. Ovariectomized female rats were fed for 12 weeks with normal rat chow, EBN, or estrogen and compared with normal non-ovariectomized rats. Metabolic indices (insulin, estrogen, superoxide dismutase, malondialdehyde, oral glucose tolerance test, and lipid profile were measured at the end of the experiment from serum and liver tissue homogenate, and transcriptional levels of hepatic insulin signaling genes were measured. The results showed that ovariectomy worsened metabolic indices and disrupted the normal transcriptional pattern of hepatic insulin signaling genes. EBN improved the metabolic indices and also produced transcriptional changes in hepatic insulin signaling genes that tended toward enhanced insulin sensitivity, and glucose and lipid homeostasis, even better than estrogen. The data suggest that EBN could meliorate estrogen deficiency-associated increase in risk of cardiometabolic disease in rats, and may in fact be useful as a functional food for the prevention of such a problem in

  1. Experiments on vibration-driven stick-slip locomotion: A sliding bifurcation perspective

    Science.gov (United States)

    Du, Zhouwei; Fang, Hongbin; Zhan, Xiong; Xu, Jian

    2018-05-01

    Dry friction appears at the contact interface between two surfaces and is the source of stick-slip vibrations. Instead of being a negative factor, dry friction is essential for vibration-driven locomotion system to take effect. However, the dry-friction-induced stick-slip locomotion has not been fully understood in previous research, especially in terms of experiments. In this paper, we experimentally study the stick-slip dynamics of a vibration-driven locomotion system from a sliding bifurcation perspective. To this end, we first design and build a vibration-driven locomotion prototype based on an internal piezoelectric cantilever. By utilizing the mechanical resonance, the small piezoelectric deformation is significantly amplified to drive the prototype to achieve effective locomotion. Through identifying the stick-slip characteristics in velocity histories, we could categorize the system's locomotion into four types and obtain a stick-slip categorization diagram. In each zone of the diagram the locomotion exhibits qualitatively different stick-slip dynamics. Such categorization diagram is actually a sliding bifurcation diagram; crossing from one stick-slip zone to another corresponds to the triggering of a sliding bifurcation. In addition, a simplified single degree-of-freedom model is established, with the rationality of simplification been explained theoretically and numerically. Based on the equivalent model, a numerical stick-slip categorization is also obtained, which shows good agreement with the experiments both qualitatively and quantitatively. To the best of our knowledge, this is the first work that experimentally generates a sliding bifurcation diagram. The obtained stick-slip categorizations deepen our understanding of stick-slip dynamics in vibration-driven systems and could serve as a base for system design and optimization.

  2. PENGEMBANGAN MODEL ALAT STICK HOCKEY UNTUK LATIHAN PEMAIN PEMULA HOCKEY

    Directory of Open Access Journals (Sweden)

    In’am Attaqi

    2016-10-01

    Full Text Available Background issues that hamper the development of hockey in Central Java due to the lack of means of stick that is expensive and so difficult to get it. The focus of this research problem is to design products hockey stick model development tool for training novice players and test products hockey stick model development tool for training novice players.The approach used in this research is the Research and Development. Phase of the study include preliminary research, design modeling, model development testing procedures, expert Judgment, small-scale trials, trials broad scale. The subject of this study is Mts Miftahussalam 1 Wonosalam Demak. Hockey expert of experts and specialists timber expert. The data analysis phase of field work and data analysis stage include observation, observation, interviews, documentation and effectiveness testing of products, expert judgment hockey expert of experts and specialists timber expert.The results of this study are the product hockey stick for beginner hockey players training in Mts Miftahussalam 1 Wonosalam.PANDAWA hockey stick product can be used as a means of practicing basic techniques for beginner hockey players, hockey stick PANDAWA product can be used as a training tool in improving the ability of the basic techniques of playing hockey, hockey stick PANDAWA product can be used as a means of playing hockey for the novice player.

  3. Fatigue effects upon sticking region and electromyography in a six-repetition maximum bench press.

    Science.gov (United States)

    van den Tillaar, Roland; Saeterbakken, Atle Hole

    2013-01-01

    The aim of the study was to examine the sticking region and concomitant neuromuscular activation of the prime movers during six-repetition maximum (RM) bench pressing. We hypothesised that both peak velocities would decrease and that the electromyography (EMG) of the prime movers (deltoid, major pectoralis and triceps) would increase during the pre-sticking and sticking region during the six repetitions due to fatigue. Thirteen resistance-trained males (age 22.8 ± 2.2 years, stature 1.82 ± 0.06 m, body mass 83.4 ± 7.6 kg) performed 6-RM bench presses. Barbell kinematics and EMG activity of pectoralis major, deltoid anterior, and triceps brachii during the pre-, sticking and post-sticking region of each repetition in a 6-RM bench press were analysed. For both the sticking as the post-sticking region, the time increased significantly from the first to the sixth repetition. Vertical barbell height at the start of sticking region was lower, while the height at the end of the sticking region and post-sticking region did not change during the six repetitions. It was concluded that in 6-RM bench pressing performance, the sticking region is a poor mechanical force region due to the unchanged barbell height at the end of the sticking region. Furthermore, when fatigue occurs, the pectoralis and the deltoid muscles are responsible for surpassing the sticking region as indicated by their increased activity during the pre- and sticking region during the six-repetitions bench press.

  4. Ice Cream Stick Math.

    Science.gov (United States)

    Paddock, Cynthia

    1992-01-01

    Described is a teaching technique which uses the collection of ice cream sticks as a means of increasing awareness of quantity in a self-contained elementary special class for students with learning disabilities and mild mental retardation. (DB)

  5. Existence of Stick-Slip Periodic Solutions in a Dry Friction Oscillator

    International Nuclear Information System (INIS)

    Li Qun-Hong; Chen Yu-Ming; Qin Zhi-Ying

    2011-01-01

    The stick-slip behavior in friction oscillators is very complicated due to the non-smoothness of the dry friction, which is the basic form of motion of dynamical systems with friction. In this paper, the stick-slip periodic solution in a single-degree-of-freedom oscillator with dry friction is investigated in detail. Under the assumption of kinetic friction being the Coulomb friction, the existence of the stick-slip periodic solution is considered to give out an analytic criterion in a class of friction systems. A two-parameter unfolding diagram is also described. Moreover, the time and states of motion on the boundary of the stick and slip motions are semi-analytically obtained in a single stick-slip period. (general)

  6. Invasive rats strengthen predation pressure on bird eggs in a South Pacific island rainforest.

    Science.gov (United States)

    Duron, Quiterie; Bourguet, Edouard; De Meringo, Hélène; Millon, Alexandre; Vidal, Eric

    2017-12-01

    Invasive rats ( Rattus spp.) are known to have pervasive impacts on island birds, particularly on their nesting success. To conserve or restore bird populations, numerous invasive rat control or eradication projects are undertaken on islands worldwide. However, such projects represent a huge investment and the decision-making process requires proper assessment of rat impacts. Here, we assessed the influence of two sympatric invasive rats ( Rattus rattus and R. exulans ) on native bird eggs in a New Caledonian rainforest, using artificial bird-nest monitoring. A total of 178 artificial nests containing two eggs of three different sizes were placed either on the ground or 1.5 m high and monitored at the start of the birds' breeding season. Overall, 12.4% of the nests were depredated during the first 7 days. At site 1, where nests were monitored during 16 days, 41.8% of the nests were depredated. The main predator was the native crow Corvus moneduloides , responsible for 62.9% of the overall predation events. Rats were responsible for only 22.9% of the events, and ate only small and medium eggs at both heights. Our experiment suggests that in New Caledonia, predation pressure by rats strengthens overall bird-nest predation, adding to that by native predators. Experimental rat control operations may allow reduced predation pressure on nests as well as the recording of biodiversity responses after rat population reduction.

  7. The effects of grip width on sticking region in bench press.

    Science.gov (United States)

    Gomo, Olav; Van Den Tillaar, Roland

    2016-01-01

    The aim of this study was to examine the occurrence of the sticking region by examining how three different grip widths affect the sticking region in powerlifters' bench press performance. It was hypothesised that the sticking region would occur at the same joint angle of the elbow and shoulder independent of grip width, indicating a poor mechanical region for vertical force production at these joint angles. Twelve male experienced powerlifters (age 27.7 ± 8.8 years, mass 91.9 ± 15.4 kg) were tested in one repetition maximum (1-RM) bench press with a narrow, medium and wide grip. Joint kinematics, timing, bar position and velocity were measured with a 3D motion capture system. All participants showed a clear sticking region with all three grip widths, but this sticking region was not found to occur at the same joint angles in all three grip widths, thereby rejecting the hypothesis that the sticking region would occur at the same joint angle of the elbow and shoulder independent of grip width. It is suggested that, due to the differences in moment arm of the barbell about the elbow joint in the sticking region, there still might be a poor mechanical region for total force production that is joint angle-specific.

  8. Stick-slip and Torsional Friction Factors in Inclined Wellbores

    Directory of Open Access Journals (Sweden)

    Aarsnes Ulf Jakob F.

    2018-01-01

    The model is shown to have a good match with the surface and downhole behavior of two deviated wellbores for depths ranging from 1500 to 3000 meters. In particular, the model replicates the amplitude and period of the oscillations, in both the topside torque and the downhole RPM, as caused by the along-string stick slip. It is further shown that by using the surface behavior of the drill-string during rotational startup, an estimate of the static and dynamic friction factors along the wellbore can be obtained, even during stick-slip oscillations, if axial tension in the drillstring is considered. This presents a possible method to estimate friction factors in the field when off-bottom stick slip is encountered, and points in the direction of avoiding stick slip through the design of an appropriate torsional start-up procedure without the need of an explicit friction test.

  9. Quantum dynamics of hydrogen atoms on graphene. II. Sticking

    Energy Technology Data Exchange (ETDEWEB)

    Bonfanti, Matteo, E-mail: matteo.bonfanti@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, v. Golgi 19, 20133 Milano (Italy); Jackson, Bret [Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Hughes, Keith H. [School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW (United Kingdom); Burghardt, Irene [Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt/Main (Germany); Martinazzo, Rocco, E-mail: rocco.martinazzo@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, v. Golgi 19, 20133 Milano (Italy); Istituto di Scienze e Tecnologie Molecolari, Consiglio Nazionale delle Richerche, v. Golgi 19, 20133 Milano (Italy)

    2015-09-28

    Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (∼0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated.

  10. Quantum dynamics of hydrogen atoms on graphene. II. Sticking

    Science.gov (United States)

    Bonfanti, Matteo; Jackson, Bret; Hughes, Keith H.; Burghardt, Irene; Martinazzo, Rocco

    2015-09-01

    Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (˜0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated.

  11. Quantum dynamics of hydrogen atoms on graphene. II. Sticking.

    Science.gov (United States)

    Bonfanti, Matteo; Jackson, Bret; Hughes, Keith H; Burghardt, Irene; Martinazzo, Rocco

    2015-09-28

    Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (∼0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated.

  12. Quantum dynamics of hydrogen atoms on graphene. II. Sticking

    International Nuclear Information System (INIS)

    Bonfanti, Matteo; Jackson, Bret; Hughes, Keith H.; Burghardt, Irene; Martinazzo, Rocco

    2015-01-01

    Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (∼0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated

  13. More Popsicle-Stick Multiplication.

    Science.gov (United States)

    Dunkels, Andrejs

    1982-01-01

    A way to use tongue depressors in a model of multiplication is presented. The original intent was to use the sticks to teach about fractions, but "mistakes" in student responses led to new ideas. It is felt that teachers should use the model in teaching multiplication. (MP)

  14. Prevalence of Needle Stick Injuries among Healthcare Workers in ...

    African Journals Online (AJOL)

    Background: Needle stick injuries represent one of the most important occupational hazards to which health workers are exposed. These injuries result from accidental piercing of the skin and or mucous membranes by sharp objects. Needle stick injuries carry the risk of exposure to blood-borne pathogens, especially ...

  15. Evaluating non-stick properties of different surface materials for contact frying

    DEFF Research Database (Denmark)

    Ashokkumar, Saranya; Adler-Nissen, Jens

    2011-01-01

    to evaluate non-stick and cleaning properties of the coatings. In accordance with industry standards pancake was selected as the food model for the non-stick properties. The performance of different frying surfaces (stainless steel, aluminium, PTFE (polytetrafluoroethylene) and three ceramic coatings with two...... on their non-stick properties, so that the smoother surfaces gave a higher force of adhesion between pancake and surface....

  16. The origin of pumice at Balmoral Beach aboriginal shell midden

    International Nuclear Information System (INIS)

    Attenbrow, V.; Sutherland, L.; Hashimoto, R.; Barron, J.

    1997-01-01

    Full text: Pumice occurs in varying amounts throughout the 2 m depth of deposits of Balmoral Beach shell midden. In one area a distinct layer of concentrated pumice occurs between 85 cm to 95 cm below present ground level. A radiocarbon date indicates that this layer was deposited around 3300 BP. Petrographic analysis of the pumice from selected levels indicates that pumice in the concentrated layer is distinct and may come from a different source from pumice in levels above and below. It contains sporadic crystals of olivine, pyroxene, feldspar, plagioclase and opaque iron oxides set in a highly vesicular rhyolite glass. Analyses of major and trace elements support such a conclusion. Geomorphological investigations indicate that Balmoral Beach formed progressively between 6000 and 2500 years ago. We hypothesize that the main pumice layer was brought in by wave action along the shoreline and derives from a raft of pumice which formed after a volcanic eruption in an as-yet unknown location. This may be local or from known drift sources, such as New Zealand, Tonga, Indonesia, the Solomon Islands or Southern Ocean sources. Results of the petrographic and major and trace element analyses suggest a potential source in the Tongan-Kermadec region. The mode of deposition of the pumice is also being investigated and will include the possibility of tsunami action

  17. Experiência de manejo de aves em áreas antrópicas, com a utilização de caixas de madeira como locais para nidificação Experimental birds managment in anthropic areas, using nest-boxes

    Directory of Open Access Journals (Sweden)

    Luiz Octavio Marcondes-Machado

    1994-01-01

    Full Text Available Use of nest-boxes for management of cavity nesting birds in anthropic areas can give good results. In November 1987, data collection begun in UNICAMP, Campinas (São Paulo, with the objective of favouring establishment and increase in urban bird communities. The House Wren (Troglodytes aedon Viellot. 1807 and House Sparrow (Passer domesticus Linnaeus, 1758 used the nest boxes for reproduction. Nests were collected and analysed (weight, used materials, incubation chamber materials, nest form. House Sparrow used thin materials, like straw, paper and plastic, while house wren used heavy materials, like sticks, wire and tabs of soff drink cans. The nest-boxes offered favorable conditions to bird reproduction and protection in disturbed areas, and showed signs of leading to increase in diversity of species, that might use this nest-boxes for reproduction in the future.

  18. 21 CFR 102.45 - Fish sticks or portions made from minced fish.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Fish sticks or portions made from minced fish. 102... for Specific Nonstandardized Foods § 102.45 Fish sticks or portions made from minced fish. (a) The common or usual name of the food product that resembles and is of the same composition as fish sticks or...

  19. Sticking it to Instruction

    OpenAIRE

    Ellie Collier

    2008-01-01

    Made to Stick: Why Some Ideas Survive and Others Die by Chip Heath & Dan Heath I always feel the need to preface my praise for this book with a little background. I’ve read a slew of best sellers on behavior. I started when a friend was raving about Malcolm Gladwell. I picked up Blink [...

  20. Sampling problems for randomly broken sticks

    Energy Technology Data Exchange (ETDEWEB)

    Huillet, Thierry [Laboratoire de Physique Theorique et Modelisation, CNRS-UMR 8089 et Universite de Cergy-Pontoise, 5 mail Gay-Lussac, 95031, Neuville sur Oise (France)

    2003-04-11

    Consider the random partitioning model of a population (represented by a stick of length 1) into n species (fragments) with identically distributed random weights (sizes). Upon ranking the fragments' weights according to ascending sizes, let S{sub m:n} be the size of the mth smallest fragment. Assume that some observer is sampling such populations as follows: drop at random k points (the sample size) onto this stick and record the corresponding numbers of visited fragments. We shall investigate the following sampling problems: (1) what is the sample size if the sampling is carried out until the first visit of the smallest fragment (size S{sub 1:n})? (2) For a given sample size, have all the fragments of the stick been visited at least once or not? This question is related to Feller's random coupon collector problem. (3) In what order are new fragments being discovered and what is the random number of samples separating the discovery of consecutive new fragments until exhaustion of the list? For this problem, the distribution of the size-biased permutation of the species' weights, as the sequence of their weights in their order of appearance is needed and studied.

  1. The Role of Lipsticks and Blush Sticks in Genetic Profiling for Human Identification

    OpenAIRE

    Nouman Rasool; Ahmad Farooq

    2016-01-01

    The core objectives of the current study are to generate human DNA profiles from used lipsticks and blush sticks of various brands available in Pakistan. A total of 12 international and local brands of lipsticks and blush sticks were selected. The lipsticks and blush sticks were applied by twenty different healthy female volunteers of 21-30 years of age. The heads of used lipsticks and blush sticks were swabbed with dry sterile cotton swabs. The qualitative and quantitative analysis was done ...

  2. Sticking it to Instruction

    Directory of Open Access Journals (Sweden)

    Ellie Collier

    2008-11-01

    Full Text Available Made to Stick: Why Some Ideas Survive and Others Die by Chip Heath & Dan Heath I always feel the need to preface my praise for this book with a little background. I’ve read a slew of best sellers on behavior. I started when a friend was raving about Malcolm Gladwell. I picked up Blink [...

  3. A Case of endoscopic retrieval of a long bamboo stick from a Humboldt penguin (Spheniscus humboldti).

    Science.gov (United States)

    Jung, Woo-Sung; Ko, Minho; Cho, Hyun Kee; Kang, Byung-Jae; Choi, Jung Hoon; Chung, Jin-Young

    2017-02-28

    An eighteen-month-old female Humboldt penguin (Spheniscus humboldti) that was 50 cm in length and 4.5 kg in weight was presented with anorexia and vomiting. The hematological and blood biochemical profiles revealed no remarkable findings, and no Salmonella, Shigella or Vibrio spp. were isolated from the fecal culture. However, radiographic imaging revealed a long linear foreign body presenting from the lower esophagus to the stomach. To retrieve this foreign body, flexible endoscopic extraction was performed using flexible rat tooth grasping forceps. A long bamboo stick (29 × 1 cm) was removed from the stomach, and the penguin fully recovered.

  4. The physics of a popsicle stick bomb

    Science.gov (United States)

    Sautel, Jérémy; Bourges, Andréane; Caussarieu, Aude; Plihon, Nicolas; Taberlet, Nicolas

    2017-10-01

    Popsicle sticks can be interlocked in the so-called "cobra weave" to form a chain under tension. When one end of the chain is released, the sticks rapidly disentangle, forming a traveling wave that propagates down the chain. In this paper, the properties of the traveling front are studied experimentally, and classical results from the theory of elasticity allow for a dimensional analysis of the height and speed of the traveling wave. The study presented here can help undergraduate students familiarize themselves with experimental techniques of image processing, and it also demonstrates the power of dimensional analysis and scaling laws.

  5. Development of Stick and Ball Sports on Gateball

    Directory of Open Access Journals (Sweden)

    Indriyanti

    2017-10-01

    Full Text Available The purpose of this research is to make product design development of stick and ball sports in gateball. The approach used in this study is a method of Research and Development. The subject of this research is the Central Java on gateball club event gateball in Semarang and Yogyakarta. Experts and expert expert gateball expert in mechanical engineering. The data analysis phase the work field, and the data analysis stage include observation, observation, interviews, and documentation of the test kefektifan products, expert judgment expert expert gateball and expert mechanical engineering expert. The results of this research are stick and ball exercise for beginner players gateball gateball. The result of the validator 3 expert expert from the expert gateball and expert mechanical engineering product validation data beginning the first phase obtained a score above 73 definitions of the criteria of “good”, on the second stage of the product validation data obtained a score above the 81 criteria for “excellent”. The results of the interviews to the development of gateball players 19 stick and ball gateball can not be used to play in a match and can be used for subsequent exercises but for beginners a product development tool model stick and ball gateball “ INC. “can be used to enhance the ability of basic techniques in motion game for players, gateball.

  6. The importance of illumination in nest site choice and nest characteristics of cavity nesting birds.

    Science.gov (United States)

    Podkowa, Paweł; Surmacki, Adrian

    2017-05-02

    Light has a significant impact on many aspects of avian biology, physiology and behaviour. An increasing number of studies show that illumination may positively influences birds' offspring fitness by e.g. acceleration of embryo development, stimulation of skeleton growth or regulation of circadian rhythm. Because nest cavities have especially low illumination, suitable light levels may be especially important for species which nest there. We may therefore expect that birds breeding in relatively dim conditions should prefer brighter nest sites and/or evolve behavioral mechanisms to secure sufficient light levels in the nest. Using nest boxes with modified internal illumination, we experimentally tested whether light regime is a cue for nest site selection of secondary cavity-nesting species. Additionally, we investigated whether nest building strategies are tuned to internal illumination. Our results demonstrate that, nest boxes with elevated illumination were chosen twice as often as dark nest boxes. Moreover, birds built higher nests in dark nest boxes than birds in boxes with elevated illumination, which suggests a mechanism of compensating for low light conditions. Our results provide the first experimental support for the idea that nest site choice and nest building behaviour in cavity-nesting birds are influenced by ambient illumination.

  7. Enclosed nests may provide greater thermal than nest predation benefits compared with open nests across latitudes

    Science.gov (United States)

    Martin, Thomas E.; Boyce, Andy J.; Fierro-Calderon, Karolina; Mitchell, Adam E.; Armstad, Connor E.; Mouton, James C.; Bin Soudi, Evertius E.

    2017-01-01

    Nest structure is thought to provide benefits that have fitness consequences for several taxa. Traditionally, reduced nest predation has been considered the primary benefit underlying evolution of nest structure, whereas thermal benefits have been considered a secondary or even non-existent factor. Yet, the relative roles of these factors on nest structures remain largely unexplored.Enclosed nests have a constructed or natural roof connected to sides that allow a restricted opening or tube entrance that provides cover in all directions except the entrance, whereas open nests are cups or platforms that are open above. We show that construction of enclosed nests is more common among songbirds (Passeriformes) in tropical and southern hemisphere regions than in north temperate regions. This geographic pattern may reflect selection from predation risk, under long-standing assumptions that nest predation rates are higher in southern regions and that enclosed nests reduce predation risk compared with open cup nests. We therefore compared nest predation rates between enclosed vs. open nests in 114 songbird species that do not nest in tree holes among five communities of coexisting birds, and for 205 non-hole-nesting species from the literature, across northern temperate, tropical, and southern hemisphere regions.Among coexisting species, enclosed nests had lower nest predation rates than open nests in two south temperate sites, but not in either of two tropical sites or a north temperate site. Nest predation did not differ between nest types at any latitude based on literature data. Among 319 species from both our field studies and the literature, enclosed nests did not show consistent benefits of reduced predation and, in fact, predation was not consistently higher in the tropics, contrary to long-standing perspectives.Thermal benefits of enclosed nests were indicated based on three indirect results. First, species that built enclosed nests were smaller than species using

  8. Incense and Joss Stick Making in Small Household Factories, Thailand

    Directory of Open Access Journals (Sweden)

    S Siripanich

    2014-07-01

    Full Text Available Background: Incense and joss stick are generally used in the world. Most products were made in small household factories. There are many environmental and occupational hazards in these factories. Objective: To evaluate the workplace environmental and occupational hazards in small household incense and joss stick factories in Roi-Et, Thailand. Methods: Nine small household factories in rural areas of Roi-Et, Thailand, were studied. Dust concentration and small aerosol particles were counted through real time exposure monitoring. The inductively coupled plasma optical emission spectrometry (ICP-OES was used for quantitative measurement of heavy metal residue in incense products. Results: Several heavy metals were found in dissolved dye and joss sticks. Those included barium, manganese, and lead. Rolling and shaking processes produced the highest concentration of dust and aerosols. Only 3.9 % of female workers used personal protection equipment. Conclusion: Dust and chemicals were major threats in small household incense and joss stick factories in Thailand. Increasing awareness towards using personal protection equipment and emphasis on elimination of environmental workplace hazards should be considered to help the workers of this industry.

  9. Transorbital impalement by a wooden stick in a 3-year-old child

    DEFF Research Database (Denmark)

    Damm, Anders; Lauritsen, Anne Øberg; Klemp, Kristian

    2015-01-01

    We present a case of a 3-year-old girl with a transorbital impalement injury due to a wooden stick penetrating the lower inferior palpebra and progressing through the orbita, after the child jumped from a table and hit a wooden basket containing pieces of exposed stick. CT revealed the stick prog...... and discharged 2 days later. Follow-up examination 2 months after the trauma demonstrated normal visual acuity and ocular motility, with no diplopia, tearing or pain....

  10. Human stick balancing: Tuning Lèvy flights to improve balance control

    Science.gov (United States)

    Cabrera, Juan Luis; Milton, John G.

    2004-09-01

    State-dependent, or parametric, noise is an essential component of the neural control mechanism for stick balancing at the fingertip. High-speed motion analysis in three dimensions demonstrates that the controlling movements made by the fingertip during stick balancing can be described by a Lévy flight. The Lévy index, α, is approximately 0.9; a value close to optimal for a random search. With increased skill, the index α does not change. However, the tails of the Lévy distribution become broader. These observations suggest a Lévy flight that is truncated by the properties of the nervous and musculoskeletal system; the truncation decreasing as skill level increases. Measurements of the cross-correlation between the position of the tip of the stick and the fingertip demonstrate that the role of closed-loop feedback changes with increased skill. Moreover, estimation of the neural latencies for stick balancing show that for a given stick length, the latency increases with skill level. It is suggested that the neural control for stick balancing involves a mechanism in which brief intervals of consciously generated, corrective movements alternate with longer intervals of prediction-free control. With learning the truncation of the Lévy flight becomes better optimized for balance control and hence the time between successive conscious corrections increases. These observations provide the first evidence that changes in a Lévy flight may have functional significance for the nervous system. This work has implications for the control of balancing problems ranging from falling in the elderly to the design of two-legged robots and earthquake proof buildings.

  11. Characterization of cosmetic sticks at Xiaohe Cemetery in early Bronze Age Xinjiang, China.

    Science.gov (United States)

    Mai, Huijuan; Yang, Yimin; Abuduresule, Idelisi; Li, Wenying; Hu, Xingjun; Wang, Changsui

    2016-01-28

    Cosmetics have been studied for a long time in the society and culture research, and its consumption is regarded as a cultural symbol of human society. This paper focuses on the analysis of the red cosmetic sticks, found in Xiaohe Cemetery (1980-1450BC), Xinjiang, China. The structure of the red cosmetic sticks was disclosed by SR-μCT scanning (Synchrotron Radiation Micro-computed Tomography), while the chemical components were characterized by FTIR (Fourier Transform Infrared Spectroscopy), Raman Spectroscopy and Proteomics. The results suggested that the cosmetic sticks were made from the cattle heart and covered with a layer of hematite powders as the pigment. Given the numerous red painted relics in Xiaohe Cemetery, this kind of cosmetic sticks might be used as a primitive form of crayon for makeup and painting. The usage of cattle hearts as cosmetic sticks is firstly reported up to our knowledge, which not only reveals the varied utilizations of cattle in Xiaohe Cemetery but also shows the distinctive religious function. Furthermore, these red cosmetic sticks were usually buried with women, implying that the woman may be the painter and play a special role in religious activities.

  12. Knowledge, attitude and practices about needle stick injuries in health care workers

    International Nuclear Information System (INIS)

    Waqar, S.H.; Siraj, M.U.; Razzaq, Z.; Malik, Z.I.; Zahid, M.A.

    2011-01-01

    Objectives: To assess knowledge, attitude and practices about needle stick Injuries in health care workers. Study type, settings and duration: Hospital based study carried out at Pakistan Institute of Medical Sciences, Islamabad, from August 2010 to November 2010. Subjects and Methods: A self administered 19 items questionnaire was prepared which contained information about needle stick injuries, its awareness, frequency of injury and the protocols that were followed after an injury had occurred. These questionnaires were given to 500 health care workers working in different wards and theaters of the hospital after obtaining their informed written consent. The health care workers included doctors, nurses and paramedical staff of Pakistan Institute of Medical Sciences, Islamabad. The data was entered and analyzed using SPSS version 15. Results: A total of 500 health care workers filled the questionnaire and returned it. Out of these 416(83.2%) reported ever experiencing needle stick injuries in their professional life. Health care workers working in Emergency department were most frequently affected (65%) followed by those working in different wards (27%) and operation theatre (8%). Most (93.6%) workers had knowledge about needle stick injuries and only 6.4% were not aware of it. Needle stick injury occurred from a brand new (unused) syringe in 51.2% cases, while in 32.8% cases, the needle caused an injury after it had been used for an injection. In 5% cases, injury occurred with blood stained needles. The commonest reasons for needle injury in stick injuries were heavy work load (36.8%) followed by hasty work (33.6%) and needle recapping (18.6%). About 66% health care workers were already vaccinated against hepatitis B. Only 13% workers followed universal guidelines of needle stick injuries and no case was reported to hospital authorities. Conclusions: Health care workers had inadequate knowledge about the risk associated with needle stick injuries and do not

  13. Constellation Stick Figures Convey Information about Gravity and Neutrinos

    Science.gov (United States)

    Mc Leod, David Matthew; Mc Leod, Roger David

    2008-10-01

    12/21/98, at America's Stonehenge, DMM detected, and drew, the full stick-figure equivalent of Canis Major, CM, as depicted by our Wolf Clan leaders, and many others. Profound, foundational physics is implied, since this occurred in the Watch House there, hours before the ``model rose.'' Similar configurations like Orion, Osiris of ancient Egypt, show that such figures are projected through solid parts of the Earth, as two-dimensional equivalents of the three-dimensional star constellations. Such ``sticks'' indicate that ``line equivalents'' connect the stars, and the physical mechanism projects outlines detectable by traditional cultures. We had discussed this ``flashlight'' effect, and recognized some of its implications. RDM states that the flashlight is a strong, distant neutrino source; the lines represent neutrinos longitudinally aligned in gravitational excitation, opaque, to earthbound, transient, transversely excited neutrinos. ``Sticks'' represent ``graviton'' detection. Neutrinos' longitudinal alignment accounts for the weakness of gravitational force.

  14. Biofuel from jute stick by pyrolysis technology

    Science.gov (United States)

    Ferdous, J.; Parveen, M.; Islam, M. R.; Haniu, H.; Takai, K.

    2017-06-01

    In this study the conversion of jute stick into biofuels and chemicals by externally heated fixed-bed pyrolysis reactor have been taken into consideration. The solid jute stick was characterized through proximate and ultimate analysis, gross calorific values and thermo-gravimetric analysis to investigate their suitability as feedstock for this consideration. The solid biomass particles were fed into the reactor by gravity feed type reactor feeder. The products were oil, char and gases. The liquid and char products were collected separately while the gas was flared into the atmosphere. The process conditions were varied by fixed-bed temperature; feed stock particle size, N2 gas flow rate and running time. All parameters were found to influence the product yields significantly. The maximum liquid yields were 50 wt% of solid jute stick at reactor temperature 425°C for N2 gas flow rate 6 l/min, feed particle size 1180-1700 µm and running time 30 min. Liquid products obtained at these conditions were characterized by physical properties, chemical analysis and GC-MS techniques. The results show that it is possible to obtained liquid products that are comparable to petroleum fuels and valuable chemical feedstock from the selected biomass if the pyrolysis conditions are chosen accordingly.

  15. The Role of Lipsticks and Blush Sticks in Genetic Profiling for Human Identification

    Directory of Open Access Journals (Sweden)

    Nouman Rasool

    2016-06-01

    Full Text Available The core objectives of the current study are to generate human DNA profiles from used lipsticks and blush sticks of various brands available in Pakistan. A total of 12 international and local brands of lipsticks and blush sticks were selected. The lipsticks and blush sticks were applied by twenty different healthy female volunteers of 21-30 years of age. The heads of used lipsticks and blush sticks were swabbed with dry sterile cotton swabs. The qualitative and quantitative analysis was done by real time polymerase chain reaction (PCR, using a Quantifiler® Duo DNA Quantification Kit on Real Time PCR ABI™ 7500. Samples were amplified for 16 STR loci using an AmpFlSTR® Identifiler® PCR amplification kit on Thermocycler ABI 9700. The amplified product was run on Applied Biosystems 3130™ Genetic Analyzer. The genetic profiles were analyzed on GeneMapper® ID-X software version 1.0. The quantification results showed that the yield of DNA obtained from lipstick samples was greater than that of DNA obtained from blush stick samples. The real-time PCR results showed that only 16% of cosmetic samples had shown inhibition. The DNA profiles obtained from all blush stick samples were of good quality compared to those from lipstick samples. No profile was obtained from one blush stick sample (DNA 0.001 ng/μL and four lipstick samples (DNA 0.001-0.003 ng/μL because the amount of DNA in each of these samples was less than the amount required for successful amplification. DNA profiles were successfully generated from most of the samples of various available brands of lipsticks and blush sticks. This is the first study proving that DNA profiles can be generated from various lip and face cosmetics.

  16. Listening in on Friction: Stick-Slip Acoustical Signatures in Velcro

    Science.gov (United States)

    Hurtado Parra, Sebastian; Morrow, Leslie; Radziwanowski, Miles; Angiolillo, Paul

    2013-03-01

    The onset of kinetic friction and the possible resulting stick-slip motion remain mysterious phenomena. Moreover, stick-slip dynamics are typically accompanied by acoustic bursts that occur temporally with the slip event. The dry sliding dynamics of the hook-and-loop system, as exemplified by Velcro, manifest stick-slip behavior along with audible bursts that are easily micrphonically collected. Synchronized measurements of the friction force and acoustic emissions were collected as hooked Velcro was driven at constant velocity over a bed of looped Velcro in an anechoic chamber. Not surprising, the envelope of the acoustic bursts maps well onto the slip events of the friction force time series and the intensity of the bursts trends with the magnitude of the difference of the friction force during a stick-slip event. However, the analysis of the acoustic emission can serve as a sensitive tool for revealing some of the hidden details of the evolution of the transition from static to kinetic friction. For instance, small acoustic bursts are seen prior to the Amontons-Coulomb threshold, signaling precursor events prior to the onset of macroscopically observed motion. Preliminary spectral analysis of the acoustic emissions including intensity-frequency data will be presented.

  17. On the reliability of archaeological rat bone for radiocarbon dating in New Zealand

    International Nuclear Information System (INIS)

    Higham, T.F.G.; Petchey, F.J.

    2000-01-01

    Holdaway and Beavan (1999) discussed the radiocarbon dating of bone of various species from the site of Hukanui Pool, Hawkes Bay. We question their conclusion that two apparently reliable rat bone gelatin determinations from the Hukanui Pool site provide support for the entire suite of rat determinations from previously dated 'natural' sites. We present evidence that contradicts their conclusion that bone material from the broad range of archaeological midden sites is generally less well-preserved than bone from 'natural' caves in New Zealand such as Hukanui Pool. We show that when dates from archaeological bone from Pleasant River and Shag River Mouth are evaluated, the state of preservation is comparable with material from the 'natural' site of Hukanui Pool, and should provide accurate and reproducible radiocarbon determinations. Our conclusion has serious implications for the acceptance of the model proposed by Holdaway (1999), because if archaeological bone is well-preserved but yields unreliable and unreproducible results, it is likely that well-preserved 'natural' bone is similarly affected. (author)

  18. Influence of olfactory and visual cover on nest site selection and nest success for grassland-nesting birds.

    Science.gov (United States)

    Fogarty, Dillon T; Elmore, R Dwayne; Fuhlendorf, Samuel D; Loss, Scott R

    2017-08-01

    Habitat selection by animals is influenced by and mitigates the effects of predation and environmental extremes. For birds, nest site selection is crucial to offspring production because nests are exposed to extreme weather and predation pressure. Predators that forage using olfaction often dominate nest predator communities; therefore, factors that influence olfactory detection (e.g., airflow and weather variables, including turbulence and moisture) should influence nest site selection and survival. However, few studies have assessed the importance of olfactory cover for habitat selection and survival. We assessed whether ground-nesting birds select nest sites based on visual and/or olfactory cover. Additionally, we assessed the importance of visual cover and airflow and weather variables associated with olfactory cover in influencing nest survival. In managed grasslands in Oklahoma, USA, we monitored nests of Northern Bobwhite ( Colinus virginianus ), Eastern Meadowlark ( Sturnella magna ), and Grasshopper Sparrow ( Ammodramus savannarum ) during 2015 and 2016. To assess nest site selection, we compared cover variables between nests and random points. To assess factors influencing nest survival, we used visual cover and olfactory-related measurements (i.e., airflow and weather variables) to model daily nest survival. For nest site selection, nest sites had greater overhead visual cover than random points, but no other significant differences were found. Weather variables hypothesized to influence olfactory detection, specifically precipitation and relative humidity, were the best predictors of and were positively related to daily nest survival. Selection for overhead cover likely contributed to mitigation of thermal extremes and possibly reduced detectability of nests. For daily nest survival, we hypothesize that major nest predators focused on prey other than the monitored species' nests during high moisture conditions, thus increasing nest survival on these

  19. Dissociative sticking of CH4 on Ru(0001)

    DEFF Research Database (Denmark)

    Nielsen, Jane Hvolbæk; Holmblad, Peter Mikal; Chorkendorff, Ib

    1999-01-01

    In this study the CH4 dissociation probability on Ru(0001) is found for various translational and vibrational energies. The absolute sticking values are determined from King and Wells experiments and carbon uptake curves. The carbon amount is determined from the recombination signal of carbon...... with oxygen obtained after the beam exposure when heating in an oxygen atmosphere. The measured sticking coefficient of CH4 is strongly enhanced both by increasing the translational and the vibrational energy of the CH4 molecule. A model is applied to the data and an estimate of the thermal activation energy...

  20. The ant nest of Crematogaster rogenhoferi (Mayr, 1879 (Hymenoptera: Formicidae at Tarutao National Park, Satun Province, Southern Thailand

    Directory of Open Access Journals (Sweden)

    Suparoek Watanasit

    2006-07-01

    Full Text Available Nests of the ant Crematogaster rogenhoferi (Mayr, 1879 were investigated at Tarutao National Park, Satun Province. Fifteen ant nests were selected at random along Phante Malacca Bay between the 2-7 March 2004. They built their nests from leaf and stick debris on branches of trees, at between 248-469 cm above the ground level. The vegetation on which nests were built was composed of 5 species: Vitex pinnata L., Oleasalicifolia Wall, Syzygium gratum (Wight, Ardisia elliptica Thum and one unknown species. The physical features of each nest were recorded. The average dimensions of the nest width and length were 10.65±2.57 cm and 22.10±1.22 cm, respectively.Each nest was cut into small pieces for counting the numbers of each caste and developing stages. The results showed that the average number of queens, winged females, males and workers in each nest were 1.53±0.38, 1,753.33±506.55, 4,970.67±2,227.00, 15,577.93±2,637.84 respectively, while the developing stages of pupae, larvae, eggs were 1,589.93±480.37, 4,113.20±1,469.49 and 1,942.80±741.67 respectively. Thus the total number of ants in the population in each nest was 29,949.40±5,358.31.The relationships between the number of castes, developing stages and physical features of the nests were explored. The Spearman Rank Correlation indicated that the width of nest positively correlated with the number of queens (rs = 0.862, p = . 000, winged females (rs = 0.691, p = 0.004 and workers (rs = 0.667, p = 0.007. A comparison of the effects of vegetation types on the number of castes and development stages, showed that vegetation type did have an influence but only on the number of the worker caste (F = 7.712, P = 0.011, one-way ANOVA. Most workers were associated with nests from Vitex pinnata. No nests were found on the dominant tree species of the area probably due to its ability to produce an insect repellant oil.

  1. Needle stick injury in a radiology department: a decade analysis

    International Nuclear Information System (INIS)

    Sayani, R.; Rajani, A.

    2012-01-01

    Objectives: To determine the frequency of needle stick injury in health care workers of radiology department. Study type, settings and duration: Cross sectional, observational study conducted at the Radiology department of Aga Khan University hospital from January 2000 to May 2010. Subject and Methods: All self-reported needle stick injuries data of Health care workers of radiology department was recorded. The personnel involved (Radiologist, resident, radiographer, nurses etc), area of working and the causes of injury were identified including the procedural or post procedural details. Patient's status of hepatitis or blood borne infection was also noted. Data was recorded and analyzed in Excel worksheet. Results: A total of 55 health workers reported needle stick injuries at all sections of radiology departments with maximum number needle stick injuries at general radiography, fluoroscopy and IVP section. Radiographers and radiology residents received the maximum number of injuries. Major cause of injury was cannulation however, many injuries occurred during disposing or handling of bin. In majority of cases the patients were not infected with any known blood borne infections. Conclusions: Doctors and nurses get needle-stick injuries while carrying out clinical procedures, while, ancillary staff get infected post procedure during disposal of garbage. Policy message: Good occupational health and safety practices must be promoted to all staff. Safer disposal of needles is an important area where practice and procedure needs to be carefully reviewed. It is necessary to undertake a risk assessment, to offer counseling and Post Exposure Prophylaxis and treatment where necessary. (author)

  2. The effect of a 10-week Zulu stick fighting intervention programme ...

    African Journals Online (AJOL)

    The article is based on the study that investigated the influence that traditional martial arts of Zulu stick fighting has on body composition of prepubescent males. A sample of fortyfive children were divided into an experimental group (n=22) which underwent a ten week stick fighting intervention programme facilitated by two ...

  3. Squeal vibrations, glass sounds, and the stick-slip effect

    International Nuclear Information System (INIS)

    Patitsas, A.J.

    2010-01-01

    The origin of the squeal acoustic emissions when a chalk is rubbed on a blackboard or better on a ceramic plate, and those when a wet finger is rubbed on a smooth surface, such as a glass surface, is sought in the stick-slip effect between the rubbing surfaces. In the case of the squealing chalk, the stick-slip effect is anchored by shear modes of vibration in about a 0.3 mm thick chalk powder band at the rubbing interface, while in the case of the wet finger on glass, by such modes in a band comprising the finger skin. Furthermore, there are the interfacial bands at the contact areas that result in the decrease of the friction coefficient with relative velocity of slide, i.e., the condition for the stick-slip effect to occur. Such bands are basically composed of the asperities on the surface of the chalk band and of the epidermis ridges and the water layer, respectively. (author)

  4. Light-stick: A problem of marine pollution in Brazil.

    Science.gov (United States)

    Cesar-Ribeiro, Caio; Rosa, Helena Costi; Rocha, Daniele Oliveira; Dos Reis, Camila Galli Baldini; Prado, Tabata Sarti; Muniz, Daniela Hernandes Coimbra; Carrasco, Raquel; Silva, Flávia Milão; Martinelli-Filho, José Eduardo; Palanch-Hans, Maria Fernanda

    2017-04-15

    Light-sticks are used as bait in surface long-line fishing, to capture swordfish and other large pelagic predators. When discharged in the ocean, it may reach the beaches. The traditional Brazilian community of Costa dos Coqueiros, Bahia, use light-sticks as a medicine for rheumatism, vitiligo and mycoses. It may affect the marine life when its content leak in the open ocean. This work evaluated and identified the acute and chronic toxicity of the light-stick. A high acute toxicity was observed in the mobility/mortality of Artemia sp.; in the fertilization of sea urchin eggs, and a high chronic toxicity in the development of the pluteus larvae of the same sea urchin. The main compounds that probably caused toxicity were the volatiles such as the fluorescent PAH and oxidants such as the hydrogen peroxide. Its disposal in the open ocean is a potential threat for marine life. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The cavity-nest ant Temnothorax crassispinus prefers larger nests.

    Science.gov (United States)

    Mitrus, S

    Colonies of the ant Temnothorax crassispinus inhabit mostly cavities in wood and hollow acorns. Typically in the field, nest sites that can be used by the ant are a limited resource. In a field experiment, it was investigated whether the ants prefer a specific size of nest, when different ones are available. In July 2011, a total of 160 artificial nests were placed in a beech-pine forest. Four artificial nests (pieces of wood with volume cavities, ca 415, 605, 730, and 980 mm 3 , respectively) were located on each square meter of the experimental plot. One year later, shortly before the emergence of new sexuals, the nests were collected. In July 2012, colonies inhabited more frequently bigger nests. Among queenright colonies, the ones which inhabited bigger nests had more workers. However, there was no relationship between volume of nest and number of workers for queenless colonies. Queenright colonies from bigger nests produced more sexual individuals, but there was no correlation between number of workers and sex allocation ratio, or between volume of nest and sex allocation ratio. In a laboratory experiment where ant colonies were kept in 470 and 860 mm 3 nests, larger colonies allocated more energy to produce sexual individuals. The results of this study show the selectivity of T. crassispinus ants regarding the size of nest cavity, and that the nest volume has an impact on life history parameters.

  6. New Surface-Treatment Technique of Concrete Structures Using Crack Repair Stick with Healing Ingredients.

    Science.gov (United States)

    Ahn, Tae-Ho; Kim, Hong-Gi; Ryou, Jae-Suk

    2016-08-04

    This study focused on the development of a crack repair stick as a new repair method along with self-healing materials that can be used to easily repair the cracks in a concrete structure at the construction site. In developing this new repair technique, the self-healing efficiency of various cementitious materials was considered. Likewise, a crack repair stick was developed to apply to concrete structures with 0.3 mm or lower crack widths. The crack repair stick was made with different materials, such as cement, an expansive material (C 12 A₇), a swelling material, and calcium carbonate, to endow it with a self-healing property. To verify the performance of the crack repair stick for concrete structures, two types of procedures (field experiment and field absorption test) were carried out. As a result of such procedures, it was concluded that the developed crack repair stick could be used on concrete structures to reduce repair expenses and for the improved workability, usability, and serviceability of such structures. On the other hand, to evaluate the self-healing performance of the crack repair stick, various tests were conducted, such as the relative dynamic modulus of elasticity test, the water tightness test, the water permeability test, observation via a microscope, and scanning electron microscope (SEM) analysis. From the results, it is found that water leakage can be prevented and that the durability of a concrete structure can be improved through self-healing. Also, it was verified that the cracks were perfectly closed after 28 days due to application of the crack repair stick. These results indicate the usability of the crack repair stick for concrete structures, and its self-healing efficiency.

  7. Development of flow-through and dip-stick immunoassays for screening of sulfonamide residues.

    Science.gov (United States)

    Zhang, Hongyan; Zhang, Yan; Wang, Shuo

    2008-08-20

    Two formats of membrane-based competitive enzyme immunoassays (flow-through and dip-stick) have been developed for the screening of sulfonamide residues in pig muscle and milk. Membrane was coated with anti-sulfonamide antibody and a sulfonamide hapten D2-horseradish peroxidase (HRP) conjugant was used as the labeled antigen for competitive assay of sulfonamides. Visual detection limits of the flow-through or dip-stick assay were 1-5 microg L(-1) or 1-10 microg L(-1) in buffer for seven sulfonamides, respectively. Assay validation was performed using samples spiked with single sulfonamide, spiked samples were tested using the developed strip assays and results were compared with those obtained by a validated high-performance liquid chromatograph (HPLC) method. Results showed that the two strip assays were correlated well with HPLC, respectively. With assay times of 5 min (flow-through) and 15 min (dip-stick), these rapid tests could offer simple, rapid and cost-effective on-site screening tools to detect sulfonamides in pig muscle (flow-through or dip-stick) or milk (only dip-stick).

  8. Effects of alloying elements on sticking occurring during hot rolling of ferritic stainless steels

    International Nuclear Information System (INIS)

    Ha, Dae Jin; Kim, Yong Jin; Lee, Yong Deuk; Lee, Sung Hak; Lee, Jong Seog

    2008-01-01

    In this study, effects of alloying elements on the sticking occurring during hot rolling of five kinds of ferritic STS430J1L stainless steels were investigated by analyzing high-temperature hardness and oxidation behavior of the rolled steels. Hot-rolling simulation tests were conducted by a high-temperature wear tester which could simulate actual hot rolling. The simulation test results revealed that the sticking process proceeded with three stages, i.e., nucleation, growth, and saturation. Since the hardness continuously decreased as the test temperature increased, whereas the formation of Fe-Cr oxides in the rolled steel surface region increased, the sticking of five stainless steels was evaluated by considering both the high-temperature hardness and oxidation effects. The addition of Zr, Cu, or Si had a beneficial effect on the sticking resistance, while the Ni addition did not show any difference in the sticking. Particularly in the case of the Si addition, Si oxides formed first in the initial stage of high-temperature oxidation, worked as initiation sites for Fe-Cr oxides, accelerated the formation of Fe-Cr oxides, and thus raised the sticking resistance by about 10 times in comparison with the steel without Si content

  9. [Survey of studies on time factor in acupoint sticking therapy for the bronchial asthma].

    Science.gov (United States)

    Huang, Dong-e; Guo, Jian-hong; Lin, Ying

    2010-02-01

    Based on the retrieval of literatures in recent fifteen years, the time factors in the acupoint sticking therapy for the bronchial asthma are analyzed and compared in terms of the stage classification of patients, timing selection of acupoint sticking therapy and medication application, and times of application. The acupoint sticking therapy is mostly practiced during remittent stage of bronchial asthma; the timing selection is mostly during the hottest period of summer, the timing selection in certain cases is the coldest period of winter or any day; the duration of medication application is not consistent; therefore, the effectiveness of these cases is different. It may be that the ef fectiveness is proportional to the times and courses of acupoint sticking therapy for the bronchial asthma. In the future, the scientific designs which involve time factor are needed to elucidate the importance of time factor in acupoint sticking therapy for the bronchial asthma.

  10. On a credit oscillatory system with the inclusion of stick-slip

    Directory of Open Access Journals (Sweden)

    Parovik Roman

    2016-01-01

    Full Text Available The work was a mathematical model that describes the effect of the sliding attachment (stick-slip, taking into account hereditarity. This model can be regarded as a mechanical model of earthquake preparation. For such a model was proposed explicit finite- difference scheme, on which were built the waveform and phase trajectories hereditarity effect of stick-slip.

  11. Method to determine the sticking coefficient of precursor molecules in atomic layer deposition

    International Nuclear Information System (INIS)

    Rose, M.; Bartha, J.W.

    2009-01-01

    A method to determine the sticking coefficient of precursor molecules used in atomic layer deposition (ALD) will be introduced. The sticking coefficient is an interesting quantity for comparing different ALD processes and reactors but it cannot be observed easily. The method relies on free molecular flow in nanoscale cylindrical holes. The sticking coefficient is determined for tetrakis(dimethylamino)titanium in combination with ozone. The proposed method can be applied independent of the type of reactor, precursor delivery system and precursors.

  12. Parametric analysis of the statistical model of the stick-slip process

    Science.gov (United States)

    Lima, Roberta; Sampaio, Rubens

    2017-06-01

    In this paper it is performed a parametric analysis of the statistical model of the response of a dry-friction oscillator. The oscillator is a spring-mass system which moves over a base with a rough surface. Due to this roughness, the mass is subject to a dry-frictional force modeled as a Coulomb friction. The system is stochastically excited by an imposed bang-bang base motion. The base velocity is modeled by a Poisson process for which a probabilistic model is fully specified. The excitation induces in the system stochastic stick-slip oscillations. The system response is composed by a random sequence alternating stick and slip-modes. With realizations of the system, a statistical model is constructed for this sequence. In this statistical model, the variables of interest of the sequence are modeled as random variables, as for example, the number of time intervals in which stick or slip occur, the instants at which they begin, and their duration. Samples of the system response are computed by integration of the dynamic equation of the system using independent samples of the base motion. Statistics and histograms of the random variables which characterize the stick-slip process are estimated for the generated samples. The objective of the paper is to analyze how these estimated statistics and histograms vary with the system parameters, i.e., to make a parametric analysis of the statistical model of the stick-slip process.

  13. Active coping with stress suppresses glucose metabolism in the rat hypothalamus.

    Science.gov (United States)

    Ono, Yumie; Lin, Hsiao-Chun; Tzen, Kai-Yuan; Chen, Hui-Hsing; Yang, Pai-Feng; Lai, Wen-Sung; Chen, Jyh-Horng; Onozuka, Minoru; Yen, Chen-Tung

    2012-03-01

    We used 18F-fluorodeoxyglucose small-animal positron-emission tomography to determine whether different styles of coping with stress are associated with different patterns of neuronal activity in the hypothalamus. Adult rats were subjected to immobilization (IMO)-stress or to a non-immobilized condition for 30 min, in random order on separate days, each of which was followed by brain-scanning. Some rats in the immobilized condition were allowed to actively cope with the stress by chewing a wooden stick during IMO, while the other immobilized rats were given nothing to chew on. Voxel-based statistical analysis of the brain imaging data shows that chewing counteracted the stress-induced increased glucose uptake in the hypothalamus to the level of the non-immobilized condition. Region-of-interest analysis of the glucose uptake values further showed that chewing significantly suppressed stress-induced increased glucose uptake in the paraventricular hypothalamic nucleus and the anterior hypothalamic area but not in the lateral hypothalamus. Together with the finding that the mean plasma corticosterone concentration at the termination of the IMO was also significantly suppressed when rats had an opportunity to chew a wooden stick, our results showed that active coping by chewing inhibited the activation of the hypothalamic-pituitary-adrenal axis to reduce the endocrine stress response.

  14. The influence of nest-site characteristics on the nesting success of ...

    African Journals Online (AJOL)

    Choice of nest site has important consequences for nest survival. We examined nest-site characteristics relative to nest success in Karoo Prinias breeding in coastal dwarf shrubland, where high nest predation is the main cause of nest failure. Initially, we compared nests that failed during the building, laying, incubation and ...

  15. Frictional melting and stick-slip behavior in volcanic conduits

    Science.gov (United States)

    Kendrick, Jackie Evan; Lavallee, Yan; Hirose, Takehiro; di Toro, Giulio; Hornby, Adrian Jakob; Hess, Kai-Uwe; Dingwell, Donald Bruce

    2013-04-01

    Dome-building eruptions have catastrophic potential, with dome collapse leading to devastating pyroclastic flows with almost no precursory warning. During dome growth, the driving forces of the buoyant magma may be superseded by controls along conduit margins; where brittle fracture and sliding can lead to formation of lubricating cataclasite and gouge. Under extreme friction, pseudotachylyte may form at the conduit margin. Understanding the conduit margin processes is vital to understanding the continuation of an eruption and we postulate that pseudotachylyte generation could be the underlying cause of stick-slip motion and associated seismic "drumbeats", which are so commonly observed at dome-building volcanoes. This view is supported by field evidence in the form of pseudotachylytes identified in lava dome products at Soufrière Hills (Montserrat) and Mount St. Helens (USA). Both eruptions were characterised by repetitive, periodic seismicity and lava spine extrusion of highly viscous magma. High velocity rotary shear (HVR) experiments demonstrate the propensity for melting of the andesitic and dacitic material (from Soufrière Hills and Mount St. Helens respectively) at upper conduit stress conditions (HVR experiments which mimic rapid velocity fluctuations in stick-slip behavior demonstrate velocity-weakening behavior of melt, with a tendency for unstable slip. During ascent, magma may slip and undergo melting along the conduit margin. In the process the shear resistance of the slip zone is increased, acting as a viscous brake halting slip (the "stick" of stick-slip motion). Sufficient buoyancy-driven pressures from ascending magma below eventually overcome resistance to produce a rapid slip event (the "slip") along the melt-bearing slip zone, which is temporarily lubricated due to velocity-weakening. New magma below experiences the same slip event more slowly (as the magma decompresses) to produce a viscous brake and the process is repeated. This allows a

  16. Vertical drying of a suspension of sticks: Monte Carlo simulation for continuous two-dimensional problem

    Science.gov (United States)

    Lebovka, Nikolai I.; Tarasevich, Yuri Yu.; Vygornitskii, Nikolai V.

    2018-02-01

    The vertical drying of a two-dimensional colloidal film containing zero-thickness sticks (lines) was studied by means of kinetic Monte Carlo (MC) simulations. The continuous two-dimensional problem for both the positions and orientations was considered. The initial state before drying was produced using a model of random sequential adsorption with isotropic orientations of the sticks. During the evaporation, an upper interface falls with a linear velocity in the vertical direction, and the sticks undergo translational and rotational Brownian motions. The MC simulations were run at different initial number concentrations (the numbers of sticks per unit area), pi, and solvent evaporation rates, u . For completely dried films, the spatial distributions of the sticks, the order parameters, and the electrical conductivities of the films in both the horizontal, x , and vertical, y , directions were examined. Significant evaporation-driven self-assembly and stratification of the sticks in the vertical direction was observed. The extent of stratification increased with increasing values of u . The anisotropy of the electrical conductivity of the film can be finely regulated by changes in the values of pi and u .

  17. Process Development for the Design and Manufacturing of Personalizable Mouth Sticks.

    Science.gov (United States)

    Berger, Veronika M; Pölzer, Stephan; Nussbaum, Gerhard; Ernst, Waltraud; Major, Zoltan

    2017-01-01

    To increase the independence of people with reduced hand/arm functionality, a process to generate personalizable mouth sticks was developed based on the participatory design principle. In a web tool, anybody can choose the geometry and the materials of their mouth piece, stick and tip. Manufacturing techniques (e.g. 3D printing) and materials used in the process are discussed and evaluated.

  18. Do artificial nests simulate nest success of greater sage-grouse?

    OpenAIRE

    Dinkins, Jonathan B.; Conover, Michael R.; Mabray, Scott T.

    2013-01-01

    Artificial nests have been used to study factors affecting nest success because researchers can manipulate them more than natural bird nests. Many researchers have questioned the validity of generalizing the results from artificial nests onto naturally occurring nests. Other studies have assessed the validity of artificial nest studies by simultaneously comparing overall depredation or daily survival rates, depredation timing, predator species, or habitat characteristics of artificial and nat...

  19. PyNEST: a convenient interface to the NEST simulator

    Directory of Open Access Journals (Sweden)

    Jochen M Eppler

    2009-01-01

    Full Text Available The neural simulation tool NEST (http://www.nest-initiative.org is a simulator for heterogeneous networks of point neurons or neurons with a small number of compartments. It aims at simulations of large neural systems with more than 10^4 neurons and 10^7 to 10^9 synapses. NEST is implemented in C++ and can be used on a large range of architectures from single-core laptops over multi-core desktop computers to super-computers with thousands of processor cores. Python (http://www.python.org is a modern programming language that has recently received considerable attention in Computational Neuroscience. Python is easy to learn and has many extension modules for scientific computing (e.g. http://www.scipy.org. In this contribution we describe PyNEST, the new user interface to NEST. PyNEST combines NEST’s efficient simulation kernel with the simplicity and flexibility of Python. Compared to NEST’s native simulation language SLI, PyNEST makes it easier to set up simulations, generate stimuli, and analyze simulation results. We describe how PyNEST connects NEST and Python and how it is implemented. With a number of examples, we illustrate how it is used.

  20. Studying friction while playing the violin: exploring the stick-slip phenomenon.

    Science.gov (United States)

    Casado, Santiago

    2017-01-01

    Controlling the stick-slip friction phenomenon is of major importance for many familiar situations. This effect originates from the periodic rupture of junctions created between two rubbing surfaces due to the increasing shear stress at the interface. It is ultimately responsible for the behavior of many braking systems, earthquakes, and unpleasant squeaky sounds caused by the scratching of two surfaces. In the case of a musical bow-stringed instrument, stick-slip is controlled in order to provide well-tuned notes at different intensities. A trained ear is able to distinguish slight sound variations caused by small friction differences. Hence, a violin can be regarded as a perfect benchmark to explore the stick-slip effect at the mesoscale. Two violin bow hairs were studied, a natural horse tail used in a professional philharmonic orchestra, and a synthetic one used with a violin for beginners. Atomic force microscopy characterization revealed clear differences when comparing the surfaces of both bow hairs, suggesting that a structure having peaks and a roughness similar to that of the string to which both bow hairs rubbed permits a better control of the stick-slip phenomenon.

  1. Variability in nest survival rates and implications to nesting studies

    Science.gov (United States)

    Klett, A.T.; Johnson, D.H.

    1982-01-01

    We used four reasonably large samples (83-213) of Mallard (Anas platyrhynchos) and Blue-winged Teal (A. discors) nests on an interstate highway right-of-way in southcentral North Dakota to evaluate potential biases in hatch-rate estimates. Twelve consecutive, weekly searches for nests were conducted with a cable-chain drag in 1976 and 1977. Nests were revisited at weekly intervals. Four methods were used to estimate hatch rates for the four data sets: the Traditional Method, the Mayfield Method, and two modifications of the Mayfield Method that are sometimes appropriate when daily mortality rates of nests are not constant. Hatch rates and the average age of nests at discovery declined as the interval between searches decreased, suggesting that mortality rates were not constant in our samples. An analysis of variance indicated that daily mortality rates varied with the age of nests in all four samples. Mortality was generally highest during the early laying period, moderately high during the late laying period, and lowest during incubation. We speculate that this relationship of mortality to nest age might be due to the presence of hens at nests or to differences in the vulnerability of nest sites to predation. A modification of the Mayfield Method that accounts for age-related variation in nest mortality was most appropriate for our samples. We suggest methods for conducting nesting studies and estimating nest success for species possessing similar nesting habits.

  2. Smart Blinding Stick with Holes,Obstacles and Ponds Detector Based on Microcontroller

    Directory of Open Access Journals (Sweden)

    Mohammed Azher Therib

    2017-08-01

    Full Text Available In this work, a device is designed and implemented that it is doing three jobs in order to help blind people to walk without accidents may occur. The first proposed one is accomplished by putting the ultrasonic sensor in a measured angle about 40o on a suitable blinding stick to detect if there is a hole or stair in front of blind at about 48 cm distance to prevent him from falling and as a result may be causing many injuries. The second one uses a moisture sensor in the first leg of the four legs stick to measure the degree of the land soil moisture in front of the blind and alert him when that degree exceeds a measured level that may immerse the feet of him. While, the third one is made by using another ultrasonic sensor on the stick to turn an alarm ON when there is an obstacle, person, or wall at a small distance about 50 cm near him to prevent a collision accident. The stick is implemented practically using four leg blinding cane, Arduino microcontroller and the three sensors. Also, the three buzzers and one vibrator motor and three LEDs are used on the stick to turn on when a such problems occur. The device gives good results when many visually impaired people in Merjan medical city in Babylon used it.

  3. A study of needle stick injuries among non-consultant hospital doctors in Ireland.

    LENUS (Irish Health Repository)

    O'Connor, M B

    2011-06-01

    NCHDs are exposed to a great number of blood-borne infections. Needle stick injuries are possibly the main route of acquiring such infections from a non-consultant hospital doctors (NCHDs) perspective. This study examines NCHDs experiences surrounding needle stick injuries.

  4. The Philippine "Hip Hop Stick Dance"

    Science.gov (United States)

    Lewis, Lisa

    2012-01-01

    This article introduces a dance that blends the traditional cultural heritage of the Philippines with modern music and moves. "Hip Hop Stick Dance" incorporates Tinikling (the Philippine national dance) and Arnis (a Filipino style of martial arts) to create a contemporary combination of rhythm, dance, and fitness. It was designed to introduce…

  5. Why wasp foundresses change nests: relatedness, dominance, and nest quality.

    Directory of Open Access Journals (Sweden)

    Perttu Seppä

    Full Text Available The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests. Females can become helpers or egglayers, effectively workers or queens. What they actually do can be predicted by a combination of ecological and relatedness factors. Advantages through increased lifetime success of individuals and nests drives foundresses of the social wasp Polistes from solitary to social nest founding. We studied reproductive options of spring foundresses of P. carolina by monitoring individually-marked wasps and assessing reproductive success of each foundress by using DNA microsatellites. We examined what behavioral decisions foundresses make after relaxing a strong ecological constraint, shortage of nesting sites. We also look at the reproductive consequences of different behaviors. As in other Polistes, the most successful strategy for a foundress was to initiate a nest as early as possible and then accept others as subordinates. A common feature for many P. carolina foundresses was, however, that they reassessed their reproductive options by actively monitoring other nests at the field site and sometimes moving permanently to new nests should that offer better (inclusive fitness prospects compared to their original nests. A clear motivation for moving to new nests was high genetic relatedness; by the end of the foundress period all females were on nests with full sisters.

  6. Why Wasp Foundresses Change Nests: Relatedness, Dominance, and Nest Quality

    Science.gov (United States)

    Seppä, Perttu; Queller, David C.; Strassmann, Joan E.

    2012-01-01

    The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests. Females can become helpers or egglayers, effectively workers or queens. What they actually do can be predicted by a combination of ecological and relatedness factors. Advantages through increased lifetime success of individuals and nests drives foundresses of the social wasp Polistes from solitary to social nest founding. We studied reproductive options of spring foundresses of P. carolina by monitoring individually-marked wasps and assessing reproductive success of each foundress by using DNA microsatellites. We examined what behavioral decisions foundresses make after relaxing a strong ecological constraint, shortage of nesting sites. We also look at the reproductive consequences of different behaviors. As in other Polistes, the most successful strategy for a foundress was to initiate a nest as early as possible and then accept others as subordinates. A common feature for many P. carolina foundresses was, however, that they reassessed their reproductive options by actively monitoring other nests at the field site and sometimes moving permanently to new nests should that offer better (inclusive) fitness prospects compared to their original nests. A clear motivation for moving to new nests was high genetic relatedness; by the end of the foundress period all females were on nests with full sisters. PMID:23049791

  7. Fracture energy of stick-slip events in a large scale biaxial experiment

    International Nuclear Information System (INIS)

    Okubo, P.G.; Dieterich, J.H.

    1981-01-01

    The concept of apparent fracture energy for the shear failure process is employed by many authors in modeling earthquake sources as dynamically extending shear cracks. Using records of shear strain and relative displacement from stick-slip events generated along a simulated, prepared fault surface in a large (1.5m x 1.5m x 0.4m) granite block and a slip-weakening model for the fault, direct estimates of the apparent shear fracture energy of the stick-slip events have been obtained. For events generated on a finely ground fault surface, apparent fracture energy ranges from 0.06 J/m 2 at a normal stress of 1.1 MPa to 0.8 J/m 2 at a normal stress of 4.6 MPa. In contrast to estimates for tensile crack formation, we find that the apparent fracture energy of stick-slip events increases linearly with normal stress. The results for the slip-weakening model for the stick-slip events are generally consistent with constitutive fault models suggested by observations of stable sliding in smaller scale experiments

  8. Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird.

    Science.gov (United States)

    Hollander, Franck A; Van Dyck, Hans; San Martin, Gilles; Titeux, Nicolas

    2015-01-01

    In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio) that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments.

  9. Nest Site Characteristics of Cavity Nesting Birds in Central Missouri

    Science.gov (United States)

    Jeffery D. Brawn; Bernice Tannenbaum; Keith E. Evans

    1984-01-01

    Two study sites in central Missouri oak-hickory forests were searched for nest sites of cavity nesting birds. Researchers located and measured 133 nests of 11 species. Cavity nesting bird habitat selection is affected by both snag characteristics and vegetation structure.

  10. Natural oils and waxes: studies on stick bases.

    Science.gov (United States)

    Budai, Lívia; Antal, István; Klebovich, Imre; Budai, Marianna

    2012-01-01

    The objective of the present article was to examine the role of origin and quantity of selected natural oils and waxes in the determination of the thermal properties and hardness of stick bases. The natural oils and waxes selected for the study were sunflower, castor, jojoba, and coconut oils. The selected waxes were yellow beeswax, candelilla wax, and carnauba wax. The hardness of the formulations is a critical parameter from the aspect of their application. Hardness was characterized by the measurement of compression strength along with the softening point, the drop point, and differential scanning calorimetry (DSC). It can be concluded that coconut oil, jojoba oil, and carnauba wax have the greatest influence on the thermal parameters of stick bases.

  11. Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird.

    Directory of Open Access Journals (Sweden)

    Franck A Hollander

    Full Text Available In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments.

  12. The Effect of Stick Stiffness of Friction Models on the Bending Behavior in Non-Bonded Flexible Risers

    OpenAIRE

    Dai, Tianjiao; Ye, Naiquan; Sævik, Svein

    2017-01-01

    This paper investigates the effect of stick stiffness on the bending behavior in non-bonded flexible risers. The stick stiffness was normally implemented in the friction model for calculating the friction stress between layers in such structures. As the stick stiffness may be too small to achieve the plane-surfaces-remain-plane assumption under low contact pressure in some friction models [1], a new friction model was proposed for maintaining the constant stick stiffness in the present work. ...

  13. Study of the influences of rotary table speed on stick-slip vibration of the drilling system

    Directory of Open Access Journals (Sweden)

    Liping Tang

    2015-12-01

    Full Text Available Stick-slip vibration presents one of the major causes of drilling problems, such as premature tool failures, low drilling efficiency and poor wellbore quality. The objective of this work is to investigate the influences of rotary table speed (RTS on stick-slip phenomenon of the drilling system. In this study, the drilling system is treated as a lumped torsional pendulum model of which the bit/rock interaction is regarded as Coulomb friction. By analyzing cases with different RTS, two types of vibrations on the bit are found: stick-slip vibration and uniform motion. With an increase in the RTS, the stick-slip vibration on the drill bit disappears once the RTS arrives at its critical value. For the cases that stick-slip vibrations occur, the phase trajectories converge toward a limit cycle. For the cases that stick-slip vibration does not appear, the drill bit tends to stabilize at a uniform motion and the phase trajectories correspond to contracting spirals observed in the phase plane.

  14. Effect of video-game experience and position of flight stick controller on simulated-flight performance.

    Science.gov (United States)

    Cho, Bo-Keun; Aghazadeh, Fereydoun; Al-Qaisi, Saif

    2012-01-01

    The purpose of this study was to determine the effects of video-game experience and flight-stick position on flying performance. The study divided participants into 2 groups; center- and side-stick groups, which were further divided into high and low level of video-game experience subgroups. The experiment consisted of 7 sessions of simulated flying, and in the last session, the flight stick controller was switched to the other position. Flight performance was measured in terms of the deviation of heading, altitude, and airspeed from their respective requirements. Participants with high experience in video games performed significantly better (p increase (0.78 %). However, after switching from a center- to a side-stick controller, performance scores decreased (4.8%).

  15. Numerical Simulations of Slow Stick Slip Events with PFC, a DEM Based Code

    Science.gov (United States)

    Ye, S. H.; Young, R. P.

    2017-12-01

    Nonvolcanic tremors around subduction zone have become a fascinating subject in seismology in recent years. Previous studies have shown that the nonvolcanic tremor beneath western Shikoku is composed of low frequency seismic waves overlapping each other. This finding provides direct link between tremor and slow earthquakes. Slow stick slip events are considered to be laboratory scaled slow earthquakes. Slow stick slip events are traditionally studied with direct shear or double direct shear experiment setup, in which the sliding velocity can be controlled to model a range of fast and slow stick slips. In this study, a PFC* model based on double direct shear is presented, with a central block clamped by two side blocks. The gauge layers between the central and side blocks are modelled as discrete fracture networks with smooth joint bonds between pairs of discrete elements. In addition, a second model is presented in this study. This model consists of a cylindrical sample subjected to triaxial stress. Similar to the previous model, a weak gauge layer at a 45 degrees is added into the sample, on which shear slipping is allowed. Several different simulations are conducted on this sample. While the confining stress is maintained at the same level in different simulations, the axial loading rate (displacement rate) varies. By varying the displacement rate, a range of slipping behaviour, from stick slip to slow stick slip are observed based on the stress-strain relationship. Currently, the stick slip and slow stick slip events are strictly observed based on the stress-strain relationship. In the future, we hope to monitor the displacement and velocity of the balls surrounding the gauge layer as a function of time, so as to generate a synthetic seismogram. This will allow us to extract seismic waveforms and potentially simulate the tremor-like waves found around subduction zones. *Particle flow code, a discrete element method based numerical simulation code developed by

  16. The Donkey and the Stick: Revisited.

    Science.gov (United States)

    Smith, Clifford E.

    The fable of the "Donkey and the Stick" is used as an analogy to present day industrial relations problems. The managerial approach of autocratic leadership has long since outlived its usefulness; rewards based along Maslow's hierarchy of needs should be used for employee motivation. The point is made from the fable that employees can't be…

  17. Earthquake source properties from instrumented laboratory stick-slip

    Science.gov (United States)

    Kilgore, Brian D.; McGarr, Arthur F.; Beeler, Nicholas M.; Lockner, David A.; Thomas, Marion Y.; Mitchell, Thomas M.; Bhat, Harsha S.

    2017-01-01

    Stick-slip experiments were performed to determine the influence of the testing apparatus on source properties, develop methods to relate stick-slip to natural earthquakes and examine the hypothesis of McGarr [2012] that the product of stiffness, k, and slip duration, Δt, is scale-independent and the same order as for earthquakes. The experiments use the double-direct shear geometry, Sierra White granite at 2 MPa normal stress and a remote slip rate of 0.2 µm/sec. To determine apparatus effects, disc springs were added to the loading column to vary k. Duration, slip, slip rate, and stress drop decrease with increasing k, consistent with a spring-block slider model. However, neither for the data nor model is kΔt constant; this results from varying stiffness at fixed scale.In contrast, additional analysis of laboratory stick-slip studies from a range of standard testing apparatuses is consistent with McGarr's hypothesis. kΔt is scale-independent, similar to that of earthquakes, equivalent to the ratio of static stress drop to average slip velocity, and similar to the ratio of shear modulus to wavespeed of rock. These properties result from conducting experiments over a range of sample sizes, using rock samples with the same elastic properties as the Earth, and scale-independent design practices.

  18. Nest use is influenced by the positions of nests and drinkers in aviaries.

    Science.gov (United States)

    Lentfer, T L; Gebhardt-Henrich, S G; Fröhlich, E K F; von Borell, E

    2013-06-01

    The influence of the nest location and the placement of nipple drinkers on nest use by laying hens in a commercial aviary was assessed. Twenty pens in a laying hen house were equipped with the same commercial aviary system, but the pens differed in the nest location and the placement of nipple drinkers. Nests were placed along the walls in 10 pens, and nipple drinkers were installed in front of the nests in 5 of these pens. The other 10 pens were equipped with nests placed on a tier within the aviary (integrated nests). Nipple drinkers were installed in front of the nests in 5 of these pens. A total of 225 Lohmann Selected Leghorns were housed per pen. The hens were offered 4 nests per pen: 2 facing the service corridor of the laying hen house and 2 facing the outdoor area. The numbers of nest eggs and mislaid eggs were counted daily per pen. At 25, 36, and 43 wk of age, the nest platforms were videotaped and the behavior of laying hens in front of the nests was analyzed. The nest location affected the stationary and locomotive behaviors in front of the nests. Hens in front of the integrated nests and the nests with drinkers displayed more stationary behaviors than hens in front of wall-placed nests or nests without drinkers. No difference in the number of nest eggs could be detected, but the integration of the nests inside the aviary led to a more even distribution of hens while nest searching. In the pens with wall-placed nests, significantly more hens laid eggs in the nests at the wall near the service corridor than at the wall near the outdoor area. Due to this imbalance, crowding in front of the preferred nests occurred and pushing and agonistic interactions on the nest platforms were significantly more frequent. Placement of nipple drinkers in front of nests had no effect on the number of eggs laid in those nests.

  19. Intermittent stick-slip dynamics during the peeling of an adhesive tape from a roller.

    Science.gov (United States)

    Cortet, Pierre-Philippe; Dalbe, Marie-Julie; Guerra, Claudia; Cohen, Caroline; Ciccotti, Matteo; Santucci, Stéphane; Vanel, Loïc

    2013-02-01

    We study experimentally the fracture dynamics during the peeling at a constant velocity of a roller adhesive tape mounted on a freely rotating pulley. Thanks to a high speed camera, we measure, in an intermediate range of peeling velocities, high frequency oscillations between phases of slow and rapid propagation of the peeling fracture. This so-called stick-slip regime is well known as the consequence of a decreasing fracture energy of the adhesive in a certain range of peeling velocity coupled to the elasticity of the peeled tape. Simultaneously with stick slip, we observe low frequency oscillations of the adhesive roller angular velocity which are the consequence of a pendular instability of the roller submitted to the peeling force. The stick-slip dynamics is shown to become intermittent due to these slow pendular oscillations which produce a quasistatic oscillation of the peeling angle while keeping constant the peeling fracture velocity (averaged over each stick-slip cycle). The observed correlation between the mean peeling angle and the stick-slip amplitude questions the validity of the usually admitted independence with the peeling angle of the fracture energy of adhesives.

  20. Occurrence and knowledge about needle stick injury in nursing students

    International Nuclear Information System (INIS)

    Prasuna, J.; Sharma, R.

    2015-01-01

    Needle stick injury (NSI) became a major issue and most of the research focuses on Nurses, Doctors and other health care workers, but at the same time nursing students in clinical duties are at high risk. Studies are available which examined NSI only in Medical students and health care workers. The present study is aimed to measure the occurrence of needle stick injury along with post exposure measures and evaluation of the knowledge regarding needle stick injury among nursing student. Methods: A cross-sectional study was conducted in North-East India in 2013. The study participants comprised of 83 nursing students studying in 4th year B.Sc. (N) and 3rd year General Nursing and Midwifery (GNM). Students were questioned regarding their occurrence to Needle Stick Injury throughout their clinical training and measures taken following the exposure. They were also asked to complete the Knowledge questionnaire on NSI. Results: The study among 83 nursing students included 43 (51.81%) GNM 3rd year and 40 (48.19%) B.Sc. Nursing Students. Out of a total 83 students, 75 (90.36%) were females. The occurrence of NSI during their course was reported by 33 (39.76%) participants. The maximum NSI occurred during first year of course (57.57%). It was found that 18 (54.54%) of NSIs were not reported. Among those exposed, only 5 (15.15%) students had undergone blood investigation and very few students took post exposure measures. It was found that, only 23 (69.69%) students were immunized against Hepatitis B before NSI. Conclusion: The present study indicated a high incidence of needle stick injuries among nursing students with more under-reported cases and subjects were not aware of post exposure measures. It is essential to deal above problems by regular training on real-life procedure at the entry level and reporting system should be more user-friendly platform. (author)

  1. Passive immunization of fetal rats with antiserum to luteinizing hormone-releasing hormone (LHRH) or transection of the central roots of the nervus terminalis does not affect rat pups' preference for home nest.

    Science.gov (United States)

    Schwanzel-Fukuda, M; Pfaff, D W

    1987-01-01

    Luteinizing hormone-releasing hormone (LHRH) is found immunocytochemically in cell bodies and fibers of the nervus terminalis, a cranial nerve which courses from the nasal septum through the cribriform plate of the ethmoid bone (medial to the olfactory and vomeronasal nerves) and enters the forebrain, caudal to the olfactory bulbs. Immunoreactive LHRH is first detected in the nervus terminalis of the fetal rat at 15 days of gestation, preceding its detection by immunocytochemistry in any other area of the brain, including the median eminence, and preceding detection of immunoreactive luteinizing hormone (LH) in the anterior pituitary. During development of the rat fetus, the nervus terminalis is the principal source of LHRH in the nervous system from days 15 through 19 of a 21 day gestation period. We tested the notion that the LHRH system of the nervus terminalis is important for olfactory performance by examining the effects of administration of antisera to LHRH during fetal development (versus saline controls), or medial olfactory peduncle transections, in the neonatal rat, which would sever the central projections of the nervus terminalis (versus lateral peduncle transection, complete transection of the olfactory peduncles and the central nervus terminalis or controls) on preferences of rat pups for home nest. The hypothesis that LHRH is important for this chemosensory response was not confirmed. Neither antisera to LHRH nor medical olfactory peduncle transection disrupted preference for home shavings. Only complete olfactory peduncle transection had a significant effect compared to unoperated and sham-operated controls.

  2. The surface temperature effect on the dissociative sticking of N2 on Fe(111)

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Hansen, Flemming Yssing; Billing, Gert Due

    1995-01-01

    We present the first realistic calculation of the surface temperature effect on the dissociative sticking probability of molecular nitrogen on Fe(111). Extensive quantum dynamical calculations show that, depending on the impact point in the unit cell, the sticking probabilities can increase as well...... as decrease as a function of the surface temperature. The magnitude of the temperature effect on randomly chosen impact points is comparable with the experimental observation. Since only a small fraction of the impacts give a significant contribution to the sticking and the alternating temperature effect...

  3. The CRESST-III iStick veto. Stable operation of multiple transition edge sensors in one readout circuit

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, Johannes [Max-Planck-Institut f. Physik (Werner-Heisenberg-Institut) (Germany); Ludwig-Maximilians-Universitaet Muenchen (Germany); Collaboration: CRESST-Collaboration

    2016-07-01

    To enable complete rejection of holder-related events in the upcoming CRESST-III dark matter search experiment, the scintillating target crystals are held by calcium tungstate sticks (iSticks) instrumented with tungsten transition edge sensors (TESs). Since the iStick signals are used exclusively for vetoing, it is sufficient to register if an event happened in any stick, without knowing which one. This allows the operation of all iSticks in a single readout circuit, requiring just one SQUID magnetometer. The talk describes the effect of bias current heating and corresponding hysteresis phenomena known in single-TES circuits, and the resulting conditions for stability in multiple-TES circuits. The fundamentally different behaviour of parallel and series circuits and resulting design choices are explored.

  4. Interactive effects between nest microclimate and nest vegetation structure confirm microclimate thresholds for Lesser Prairie-Chicken nest survival

    Science.gov (United States)

    Grisham, Blake A.; Godar, Alixandra J.; Boal, Clint W.; Haukos, David A.

    2016-01-01

    The range of Lesser Prairie-Chickens (Tympanuchus pallidicinctus) spans 4 unique ecoregions along 2 distinct environmental gradients. The Sand Shinnery Oak Prairie ecoregion of the Southern High Plains of New Mexico and Texas is environmentally isolated, warmer, and more arid than the Short-Grass, Sand Sagebrush, and Mixed-Grass Prairie ecoregions in Colorado, Kansas, Oklahoma, and the northeast panhandle of Texas. Weather is known to influence Lesser Prairie-Chicken nest survival in the Sand Shinnery Oak Prairie ecoregion; regional variation may also influence nest microclimate and, ultimately, survival during incubation. To address this question, we placed data loggers adjacent to nests during incubation to quantify temperature and humidity distribution functions in 3 ecoregions. We developed a suite of a priori nest survival models that incorporated derived microclimate parameters and visual obstruction as covariates in Program MARK. We monitored 49 nests in Mixed-Grass, 22 nests in Sand Shinnery Oak, and 30 nests in Short-Grass ecoregions from 2010 to 2014. Our findings indicated that (1) the Sand Shinnery Oak Prairie ecoregion was hotter and drier during incubation than the Mixed- and Short-Grass ecoregions; (2) nest microclimate varied among years within ecoregions; (3) visual obstruction was positively associated with nest survival; but (4) daily nest survival probability decreased by 10% every half-hour when temperature was greater than 34°C and vapor pressure deficit was less than −23 mmHg during the day (about 0600–2100 hours). Our major finding confirmed microclimate thresholds for nest survival under natural conditions across the species' distribution, although Lesser Prairie-Chickens are more likely to experience microclimate conditions that result in nest failures in the Sand Shinnery Oak Prairie ecoregion. The species would benefit from identification of thermal landscapes and management actions that promote cooler, more humid nest microclimates.

  5. Prevalence of needle stick injuries among healthcare workers

    African Journals Online (AJOL)

    Abe Olugbenga

    stick injury among healthcare workers at the Federal Medical Centre (FMC), Owerri. Materials and ... health workers when exposed to work .... factors and prevention of Health care workers at .... software called Statistical Package for Social.

  6. Numerical analysis for the stick-slip vibration of a transversely moving beam in contact with a frictional wall

    Science.gov (United States)

    Won, Hong-In; Chung, Jintai

    2018-04-01

    This paper presents a numerical analysis for the stick-slip vibration of a transversely moving beam, considering both stick-slip transition and friction force discontinuity. The dynamic state of the beam was separated into the stick state and the slip state, and boundary conditions were defined for both. By applying the finite element method, two matrix-vector equations were derived: one for stick state and the other for slip state. However, the equations have different degrees of freedom depending on whether the end of a beam sticks or slips, so we encountered difficulties in time integration. To overcome the difficulties, we proposed a new numerical technique to alternatively use the matrix-vector equations with different matrix sizes. In addition, to eliminate spurious high-frequency responses, we applied the generalized-α time integration method with appropriate value of high-frequency numerical dissipation. Finally, the dynamic responses of stick-slip vibration were analyzed in time and frequency domains: the dynamic behavior of the beam was explained to facilitate understanding of the stick-slip motion, and frequency characteristics of the stick-slip vibration were investigated in relation to the natural frequencies of the beam. The effects of the axial load and the moving speed upon the dynamic response were also examined.

  7. Nest Mosquito Trap quantifies contact rates between nesting birds and mosquitoes.

    Science.gov (United States)

    Caillouët, Kevin A; Riggan, Anna E; Rider, Mark; Bulluck, Lesley P

    2012-06-01

    Accurate estimates of host-vector contact rates are required for precise determination of arbovirus transmission intensity. We designed and tested a novel mosquito collection device, the Nest Mosquito Trap (NMT), to collect mosquitoes as they attempt to feed on unrestrained nesting birds in artificial nest boxes. In the laboratory, the NMT collected nearly one-third of the mosquitoes introduced to the nest boxes. We then used these laboratory data to estimate our capture efficiency of field-collected bird-seeking mosquitoes collected over 66 trap nights. We estimated that 7.5 mosquitoes per trap night attempted to feed on nesting birds in artificial nest boxes. Presence of the NMT did not have a negative effect on avian nest success when compared to occupied nest boxes that were not sampled with the trap. Future studies using the NMT may elucidate the role of nestlings in arbovirus transmission and further refine estimates of nesting bird and vector contact rates. © 2012 The Society for Vector Ecology.

  8. Maternal and littermate deprivation disrupts maternal behavior and social-learning of food preference in adulthood: tactile stimulation, nest odor, and social rearing prevent these effects.

    Science.gov (United States)

    Melo, Angel I; Lovic, Vedran; Gonzalez, Andrea; Madden, Melissa; Sinopoli, Katia; Fleming, Alison S

    2006-04-01

    Maternal and littermate (social) separation, through artificial rearing (AR), disrupts the development of subsequent maternal behavior and social learning in rats. The addition of maternal-licking-like stimulation during AR, partially reverses some of these effects. However, little is know about the role of social stimuli from littermates and nest odors during the preweaning period, in the development of the adult maternal behavior and social learning. The purpose of this study was to examine the effects of peer- and peer-and-odor rearing on the development of maternal behavior and social learning in rats. Female pups were reared with mothers (mother reared-MR) or without mothers (AR) from postnatal day (PND) 3. AR rats received three different treatments: (1) AR-CONTROL group received minimal tactile stimulation, (2) AR-ODOR females received exposure to maternal nest material inside the AR-isolation-cup environment, (3) AR-SOCIAL group was reared in the cup with maternal nest material and a conspecific of the same-age and same-sex and received additional tactile stimulation. MR females were reared by their mothers in the nest and with conspecifics. In adulthood, rats were tested for maternal behavior towards their own pups and in a social learning task. Results confirm our previous report that AR impairs performance of maternal behavior and the development of a social food preference. Furthermore, social cues from a littermate, in combination with tactile stimulation and the nest odor, reversed the negative effects of complete isolation (AR-CONTROL) on some of the above behaviors. Exposure to the odor alone also had effects on some of these olfactory-mediated behaviors. These studies indicate that social stimulation from littermates during the preweaning period, in combination with odor from the nest and tactile stimulation, contributes to the development of affiliative behaviors. Copyright (c) 2006 Wiley Periodicals, Inc.

  9. Sticking efficiency of nanoparticles in high-velocity collisions with various target materials

    International Nuclear Information System (INIS)

    Reissaus, Philipp; Waldemarsson, Tomas; Blum, Juergen; Clement, Dominik; Llamas, Isabel; Mutschke, Harald; Giovane, Frank

    2006-01-01

    In order to find reliable collector surfaces for the Mesospheric Aerosol - Genesis, Interaction and Composition (MAGIC) sounding rocket experiment, intended to collect atmospheric nanoparticles, the sticking efficiency of nanoparticles was measured on several targets of different materials. The nanoparticles were generated by a molecular beam apparatus in Jena, Germany, by laser ablation (Al 2 O 3 particles, diameter 5-50 nm) and by laser pyrolysis (carbon particles, diameter 10-20 nm). In a vacuum environment (>10 -5 mbar) the particles condensed from the gas phase, formed a particle beam, and were accelerated to ∼∼1 km/s. The sticking efficiency on the target materials carbon, gold and grease was measured by a microbalance. Results demonstrate moderate to high sticking probabilities. Thus, the capture and retrieval of atmospheric nanoparticles was found to be quantitatively feasible

  10. Mourning Dove nesting habitat and nest success in Central Missouri

    Science.gov (United States)

    Drobney, R.D.; Schulz, J.H.; Sheriff, S.L.; Fuemmeler, W.J.

    1998-01-01

    Previous Mourning Dove (Zenaida macroura) nesting studies conducted in areas containing a mixture of edge and continuous habitats have focused on edge habitats. Consequently, little is known about the potential contribution of continuous habitats to dove production. In this study we evaluated the relative importance of these two extensive habitat types by monitoring the habitat use and nest success of 59 radio-marked doves during 1990-1991 in central Missouri. Of 83 nests initiated by our marked sample, most (81.9%) were located in edge habitats. Although continuous habitats were selected less as nest sites, the proportion of successful nests did not differ significantly from that in edge habitats. Our data indicate that continuous habitats should not be considered marginal nesting habitat. If the intensity of use and nest success that we observed are representative regionally or nationally, continuous habitats could contribute substantially to annual Mourning Dove production because of the high availability of these habitats throughout much of the Mourning Dove breeding range.

  11. Determination of the sticking coefficient of low-energy hydrocarbon ions

    International Nuclear Information System (INIS)

    Tichmann, Klaus Markus

    2011-01-01

    The maximum lifetime of future fusion facilities like ITER will be limited by the retention of radioactive tritium in the vessel walls. The retention is significantly affected by the sticking coefficient of hydrocarbon molecules that form in the machine. Using a particle-beam experiment, this sticking coefficient was determined for multiple species at energies below 200 eV. The equipment for the production of the particle beam was optimised and a new ion source for hydrocarbon ions was developed. Simulations using molecular dynamics were performed in parallel to improve the understanding of the processes at the surface.

  12. PIGE-PIXE analysis of chewing sticks of pharmacological importance

    Energy Technology Data Exchange (ETDEWEB)

    Olabanji, S.O. [Istituto Nazionale di Fisica Nucleare (INFN), Padua (Italy). Lab. Nazionali di Legnaro; Makanju, O.V. [Drug Research and Production Unit, Faculty of Pharmacy, Obafemi Awolowo University (O.A.U.), Ile-Ife (Nigeria); Haque, A.M.I. [Istituto Nazionale di Fisica Nucleare (INFN), Padua (Italy). Lab. Nazionali di Legnaro; Buoso, M.C. [Istituto Nazionale di Fisica Nucleare (INFN), Padua (Italy). Lab. Nazionali di Legnaro; Ceccato, D. [Istituto Nazionale di Fisica Nucleare (INFN), Padua (Italy). Lab. Nazionali di Legnaro]|[Dipartimento di Fisica, Universita di Padova, I-35131 Padova (Italy); Cherubini, R. [Istituto Nazionale di Fisica Nucleare (INFN), Padua (Italy). Lab. Nazionali di Legnaro; Moschini, G. [Istituto Nazionale di Fisica Nucleare (INFN), Padua (Italy). Lab. Nazionali di Legnaro]|[Dipartimento di Fisica, Universita di Padova, I-35131 Padova (Italy)

    1996-06-01

    PIGE and PIXE techniques were employed for the determination of the major, minor and trace elemental concentrations in chewing sticks of pharmacological importance namely: Butyrospermum paradoxum, Garcinia kola, Distemonanthus benthamianus, Bridelia ferruginea, Anogeissus leiocarpus, Terminalia glaucescens and Fagara rubescens, respectively. The concentration of fluorine which is very important for human dental enamel was specially determined using the {sup 19}F(p,p`{gamma}){sup 19}F reaction. For decades these chewing sticks when used alone without toothpastes have proven to be very efficient, effective and reliable in cleaning the teeth of many people particularly in Nigeria and some other countries in Africa. The teeth of users are usually very strong, clean, fresh and devoid of germs and caries. Even with the advent of modern toothpastes with special additions of fluorine, the use of these popular and efficient chewing sticks is still unabated. Many people including the elite use them solely, a few others combine their use with modern toothpastes and brush. Proton beams produced by the 7 MV CN and 2.5 MV AN 2000 Van de Graaff accelerators at INFN, Laboratori Nazionali di Legnaro (LNL), Padova, Italy were used for the PIGE and PIXE analysis, respectively. Results of this novel study are presented and discussed. (orig.).

  13. PIGE-PIXE analysis of chewing sticks of pharmacological importance

    International Nuclear Information System (INIS)

    Olabanji, S.O.; Haque, A.M.I.; Cherubini, R.

    1996-01-01

    PIGE and PIXE techniques were employed for the determination of the major, minor and trace elemental concentrations in chewing sticks of pharmacological importance namely: Butyrospermum paradoxum, Garcinia kola, Distemonanthus benthamianus, Bridelia ferruginea, Anogeissus leiocarpus, Terminalia glaucescens and Fagara rubescens, respectively. The concentration of fluorine which is very important for human dental enamel was specially determined using the 19 F(p,p'γ) 19 F reaction. For decades these chewing sticks when used alone without toothpastes have proven to be very efficient, effective and reliable in cleaning the teeth of many people particularly in Nigeria and some other countries in Africa. The teeth of users are usually very strong, clean, fresh and devoid of germs and caries. Even with the advent of modern toothpastes with special additions of fluorine, the use of these popular and efficient chewing sticks is still unabated. Many people including the elite use them solely, a few others combine their use with modern toothpastes and brush. Proton beams produced by the 7 MV CN and 2.5 MV AN 2000 Van de Graaff accelerators at INFN, Laboratori Nazionali di Legnaro (LNL), Padova, Italy were used for the PIGE and PIXE analysis, respectively. Results of this novel study are presented and discussed. (orig.)

  14. PIGE-PIXE analysis of chewing sticks of pharmacological importance

    Science.gov (United States)

    Olabanji, S. O.; Makanju, O. V.; Haque, A. M. I.; Buoso, M. C.; Ceccato, D.; Cherubini, R.; Moschini, G.

    1996-06-01

    PIGE and PIXE techniques were employed for the determination of the major, minor and trace elemental concentrations in chewing sticks of pharmacological importance namely: Butyrospermum paradoxum, Garcinia kola, Distemonanthus benthamianus, Bridelia ferruginea, Anogeissus leiocarpus, Terminalia glaucescens and Fagara rubescens, respectively. The concentration of fluorine which is very important for human dental enamel was specially determined using the 19F(p, p'γ) 19F reaction. For decades these chewing sticks when used alone without toothpastes have proven to be very efficient, effective and reliable in cleaning the teeth of many people particularly in Nigeria and some other countries in Africa. The teeth of users are usually very strong, clean, fresh and devoid of germs and caries. Even with the advent of modern toothpastes with special additions of fluorine, the use of these popular and efficient chewing sticks is still unabated. Many people including the elite use them solely, a few others combine their use with modern toothpastes and brush. Proton beams produced by the 7 MV CN and 2.5 MV AN 2000 Van de Graaff accelerators at INFN, Laboratori Nazionali di Legnaro (LNL), Padova, Italy were used for the PIGE and PIXE analysis, respectively. Results of this novel study are presented and discussed.

  15. Craft Stick Beams

    Science.gov (United States)

    Karplus, Alan K.

    1996-01-01

    The objective of this exercise is to provide a phenomenological 'hands-on' experience that shows how geometry can affect the load carrying capacity of a material used in construction, how different materials have different failure characteristics, and how construction affects the performance of a composite material. This will be accomplished by building beams of a single material and composite beams of a mixture of materials (popsicle sticks, fiberboard sheets, and tongue depressors); testing these layered beams to determine how and where they fail; and based on the failure analysis, designing a layered beam that will fail in a predicted manner. The students will learn the effects of lamination, adhesion, and geometry in layered beam construction on beam strength and failure location.

  16. Construction patterns of birds’ nests provide insight into nest-building behaviours

    Directory of Open Access Journals (Sweden)

    Lucia Biddle

    2017-02-01

    Full Text Available Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch (Pyrrhula pyrrhula nests as a model for open-nesting songbird species that construct a “twig” nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process.

  17. Construction patterns of birds’ nests provide insight into nest-building behaviours

    Science.gov (United States)

    Goodman, Adrian M.

    2017-01-01

    Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch (Pyrrhula pyrrhula) nests as a model for open-nesting songbird species that construct a “twig” nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process. PMID:28265501

  18. Construction patterns of birds' nests provide insight into nest-building behaviours.

    Science.gov (United States)

    Biddle, Lucia; Goodman, Adrian M; Deeming, D Charles

    2017-01-01

    Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch ( Pyrrhula pyrrhula ) nests as a model for open-nesting songbird species that construct a "twig" nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process.

  19. Creep to inertia dominated stick-slip behavior in sliding friction modulated by tilted non-uniform loading

    Science.gov (United States)

    Tian, Pengyi; Tao, Dashuai; Yin, Wei; Zhang, Xiangjun; Meng, Yonggang; Tian, Yu

    2016-09-01

    Comprehension of stick-slip motion is very important for understanding tribological principles. The transition from creep-dominated to inertia-dominated stick-slip as the increase of sliding velocity has been described by researchers. However, the associated micro-contact behavior during this transition has not been fully disclosed yet. In this study, we investigated the stick-slip behaviors of two polymethyl methacrylate blocks actively modulated from the creep-dominated to inertia-dominated dynamics through a non-uniform loading along the interface by slightly tilting the angle of the two blocks. Increasing the tilt angle increases the critical transition velocity from creep-dominated to inertia-dominated stick-slip behaviors. Results from finite element simulation disclosed that a positive tilt angle led to a higher normal stress and a higher temperature on blocks at the opposite side of the crack initiating edge, which enhanced the creep of asperities during sliding friction. Acoustic emission (AE) during the stick-slip has also been measured, which is closely related to the different rupture modes regulated by the distribution of the ratio of shear to normal stress along the sliding interface. This study provided a more comprehensive understanding of the effect of tilted non-uniform loading on the local stress ratio, the local temperature, and the stick-slip behaviors.

  20. Multielement analysis of Nigerian chewing sticks by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Asubiojo, O.I.; Guinn, V.P.

    1982-01-01

    In Nigeria, various parts of various species of native plants have long been used for dental hygiene, with reportedly considerable effectiveness. These materials are known as 'chewing sticks'. This study was an effort to ascertain whether any unusual trace element concentrations might be present in Nigerian chewing sticks. Results are presented for 17 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Mn, Fe, Co, Zn, Br, Cs, La, Sm, Au) detected and measured in 12 species of such plants, via instrumental thermal-neutron activation analysis. (author)

  1. Design and Experimental Research of a Novel Stick-Slip Type Piezoelectric Actuator

    Directory of Open Access Journals (Sweden)

    Mingxing Zhou

    2017-05-01

    Full Text Available A linear piezoelectric actuator based on the stick-slip principle is presented and tested in this paper. With the help of changeable vertical preload force flexure hinge, the designed linear actuator can achieve both large travel stick-slip motion and high-resolution stepping displacement. The developed actuator mainly consists of a bridge-type flexure hinge mechanism, a compound parallelogram flexure hinge mechanism, and two piezoelectric stacks. The mechanical structure and motion principle of the linear actuator were illustrated, and the finite element method (FEM is adopted. An optimal parametric study of the flexure hinge is performed by a finite element analysis-based response surface methodology. In order to investigate the actuator’s working performance, a prototype was manufactured and a series of experiments were carried out. The results indicate that the maximum motion speed is about 3.27 mm/s and the minimum stepping displacement is 0.29 μm. Finally, a vibration test was carried out to obtain the first natural frequency of the actuator, and an in situ observation was conducted to investigate actuator’s stick-slip working condition. The experimental results confirm the feasibility of the proposed actuator, and the motion speed and displacement are both improved compared with the traditional stick-slip motion actuator.

  2. Evaluation of rheological, bioactives and baking characteristics of mango ginger (curcuma amada) enriched soup sticks.

    Science.gov (United States)

    Crassina, K; Sudha, M L

    2015-09-01

    Wheat flour was replaced with mango ginger powder (MGP) at 0, 5, 10 and 15 %. Influence of MGP on rheological and baking characteristics was studied. Farinograph was used to study the mixing profile of wheat flour-MGP blend. Pasting profile of the blends namely gelatinization and retrogradation were carried out using micro-visco-amylograph. Test baking was done to obtain the optimum level of replacement and processing conditions. Sensory attributes consisting texture, taste, overall quality and breaking strength were assessed. Nutritional characterization of the soup sticks in terms of protein and starch in vitro digestibility, dietary fiber, minerals, polyphenols and antioxidant activity were determined using standard methods. With the increasing levels of MGP from 0 to 15 %, the farinograph water absorption increased from 60 to 66.7 %. A marginal increase in the gelatinization temperature from 65.4 to 66.2 °C was observed. Retrogradation of gelatinized starch granules decreased with the addition of MGP. The results indicated that the soup stick with 10 % MG had acceptable sensory attributes. The soup stick showed further improvement in terms of texture and breaking strength with the addition of gluten powder, potassium bromate and glycerol monostearate. The total dietary fiber and antioxidant activity of the soup sticks having 10 % MGP increased from 3.31 to 8.64 % and 26.83 to 48.06 % respectively as compared to the control soup sticks. MGP in soup sticks improved the nutritional profile.

  3. An experimental and numerical investigation of head dynamics due to stick impacts in girls' lacrosse.

    Science.gov (United States)

    Morse, Justin D; Franck, Jennifer A; Wilcox, Bethany J; Crisco, Joseph J; Franck, Christian

    2014-12-01

    A method of investigating head acceleration and intracranial dynamics from stick impacts in girls' and women's lacrosse was developed using headform impact experiments and a finite element head model. Assessing the likelihood of head injury due to stick-head impacts is of interest in girls' and women's lacrosse due to the current lack of head protection during play. Experimental and simulation data were compared to characterize the head acceleration caused by stick-head impacts. Validation against cadaver head impact experiments ensures that the finite element model, with its relatively simple material properties, can provide means to develop a better understanding of the intracranial dynamics during lacrosse stick impacts. Our numerical results showed the peak acceleration at the center of gravity increased linearly with impact force, and was generally in agreement with the experimental data. von Mises stresses and peak principal strains, two common literature injury indicators, were examined within the finite element model, and peak values were below the previously reported thresholds for mild traumatic brain injury. By reconstructing typical in-game, unprotected stick-head impacts, this investigation lays the foundation for a quantitative methodology of injury prediction in girls' and womens' lacrosse.

  4. Phytochemical screening and mineral composition of chewing sticks ...

    African Journals Online (AJOL)

    Phytochemical screening of the stems of Garcinia kola, Dennettia tripetala, Acioa barteri, Dialium guineense, Maesobotrya barteri, Mallotus oppositifolius and Psidium guajava which are commonly used as chewing sticks in southern Nigeria revealed the presence of bioactive compounds comprising saponins, tannins, ...

  5. 'Food Sticking in My Throat': Videofluoroscopic Evaluation of a Common Symptom.

    Science.gov (United States)

    Madhavan, Aarthi; Carnaby, Giselle D; Crary, Michael A

    2015-06-01

    Prevalence of the symptom of food 'sticking' during swallowing has been reported to range from 5 to 50%, depending on the assessment setting. However, limited objective evidence has emerged to clarify factors that contribute to this symptom. Three hundred and fifteen patient records from an outpatient dysphagia clinic were reviewed to identify patients with symptoms of 'food sticking in the throat.' Corresponding videofluoroscopic swallowing studies for patients with this complaint were reviewed for the following variables: accuracy of symptom localization, identification and characteristics (anatomic, physiologic) of an explanatory cause for the symptom, and the specific swallowed material that identified the explanatory cause. One hundred and forty one patients (45%) were identified with a complaint of food 'sticking' in their throat during swallowing. Prevalence of explanatory findings on fluoroscopy was 76% (107/141). Eighty five percent (91/107) of explanatory causes were physiologic in nature, while 15% (16/107) were anatomic. The majority of explanatory causes were identified in the esophagus (71%). Symptom localization was more accurate when the explanatory cause was anatomic versus physiologic (75 vs. 18%). A non-masticated marshmallow presented with the highest diagnostic yield in identification of explanatory causes (71%). Patients complaining of 'food sticking in the throat' are likely to present with esophageal irregularities. Thus, imaging studies of swallowing function should include the esophagus. A range of materials, including a non-masticated marshmallow, is helpful in determining the location and characteristics of swallowing deficits contributing to this symptom.

  6. Multielement analysis of Nigerian chewing sticks by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Asubiojo, O.I.; Guinn, V.P. (California Univ., Irvine (USA). Dept. of Chemistry); Okunuga, A. (California Polytechnic Univ., Pomona, CA (USA))

    1982-01-01

    In Nigeria, various parts of various species of native plants have long been used for dental hygiene, with reportedly considerable effectiveness. These materials are known as 'chewing sticks'. This study was an effort to ascertain whether any unusual trace element concentrations might be present in Nigerian chewing sticks. Results are presented for 17 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Mn, Fe, Co, Zn, Br, Cs, La, Sm, Au) detected and measured in 12 species of such plants, via instrumental thermal-neutron activation analysis.

  7. Molecular beam study of dissociative sticking of methane on Ni(100)

    DEFF Research Database (Denmark)

    Holmblad, Peter Mikal; Wambach, Jørg; Chorkendorff, Ib

    1995-01-01

    of the methane leads to a dramatic enhancement of the sticking, emphasizing that the initial vibrational state is of crucial importance. These results are consistent with a mechanism of direct activated dissociative chemisorption where the dynamics is dominated by a barrier in the potential energy surface mainly...... located in the vibrational coordinates. Normal-energy scaling is only approximately observed. The effect of surface temperature is also investigated but is found to be smaller than activation by translational or vibrational energy. A simplified analysis in terms of state resolved sticking curves, Snu...... American Institute of Physics....

  8. Vehicle steering by side stick: optimising steering characteristics

    NARCIS (Netherlands)

    Zuurbier, J.; Hogema, J.H.; Brekelmans, J.A.W.J.

    2000-01-01

    This paper describes a study that was conducted to investigate the possibilities for optimizing task performance when driving a side stick-steered vehicle. Using steer-by-wire technology, a conventional steering system was mimicked, thus yielding the possibility to modify the steering

  9. A diet high in fat and sugar reverses anxiety-like behaviour induced by limited nesting in male rats: Impacts on hippocampal markers.

    Science.gov (United States)

    Maniam, Jayanthi; Antoniadis, Christopher P; Le, Vivian; Morris, Margaret J

    2016-06-01

    Stress exposure during early development is known to produce long-term mental health deficits. Stress promotes poor lifestyle choices such as poor diet. Early life adversity and diets high in fat and sugar (HFHS) are known to affect anxiety and memory. However additive effects of HFHS and stress during early development are less explored. Here, we examined whether early life stress (ELS) simulated by limited nesting (LN) induces anxiety-like behaviour and cognitive deficits that are modulated by HFHS diet. We examined key hippocampal markers involved in anxiety and cognition, testing the hypothesis that post-weaning HFHS following ELS would ameliorate anxiety-like behaviour but worsen memory and associated hippocampal changes. Sprague-Dawley rats were exposed to LN, postnatal days 2-9, and at weaning, male siblings were given unlimited access to chow or HFHS resulting in (Con-Chow, Con-HFHS, LN-Chow, LN-HFHS, n=11-15/group). Anxiety-like behaviour was assessed by Elevated Plus Maze (EPM) at 10 weeks and spatial and object recognition tested at 11 weeks of age. Rats were culled at 13 weeks. Hippocampal mRNA expression was measured using TaqMan(®) Array Micro Fluidic cards (Life Technologies). As expected HFHS diet increased body weight; LN and control rats had similar weights at 13 weeks, energy intake was also similar across groups. LN-Chow rats showed increased anxiety-like behaviour relative to control rats, but this was reversed by HFHS diet. Spatial and object recognition memory were unaltered by LN exposure or consumption of HFHS diet. Hippocampal glucocorticoid receptor (GR) protein was not affected by LN exposure in chow rats, but was increased by 45% in HFHS rats relative to controls. Hippocampal genes involved in plasticity and mood regulation, GSKα and GSKβ were affected, with reductions in GSKβ under both diet conditions, and reduced GSKα only in LN-HFHS versus Con-HFHS. Interestingly, HFHS diet and LN exposure independently reduced expression of

  10. Spatio-temporal foreshock activity during stick-slip experiments of large rock samples

    Science.gov (United States)

    Tsujimura, Y.; Kawakata, H.; Fukuyama, E.; Yamashita, F.; Xu, S.; Mizoguchi, K.; Takizawa, S.; Hirano, S.

    2016-12-01

    Foreshock activity has sometimes been reported for large earthquakes, and has been roughly classified into the following two classes. For shallow intraplate earthquakes, foreshocks occurred in the vicinity of the mainshock hypocenter (e.g., Doi and Kawakata, 2012; 2013). And for intraplate subduction earthquakes, foreshock hypocenters migrated toward the mainshock hypocenter (Kato, et al., 2012; Yagi et al., 2014). To understand how foreshocks occur, it is useful to investigate the spatio-temporal activities of foreshocks in the laboratory experiments under controlled conditions. We have conducted stick-slip experiments by using a large-scale biaxial friction apparatus at NIED in Japan (e.g., Fukuyama et al., 2014). Our previous results showed that stick-slip events repeatedly occurred in a run, but only those later events were preceded by foreshocks. Kawakata et al. (2014) inferred that the gouge generated during the run was an important key for foreshock occurrence. In this study, we proceeded to carry out stick-slip experiments of large rock samples whose interface (fault plane) is 1.5 meter long and 0.5 meter wide. After some runs to generate fault gouge between the interface. In the current experiments, we investigated spatio-temporal activities of foreshocks. We detected foreshocks from waveform records of 3D array of piezo-electric sensors. Our new results showed that more than three foreshocks (typically about twenty) had occurred during each stick-slip event, in contrast to the few foreshocks observed during previous experiments without pre-existing gouge. Next, we estimated the hypocenter locations of the stick-slip events, and found that they were located near the opposite end to the loading point. In addition, we observed a migration of foreshock hypocenters toward the hypocenter of each stick-slip event. This suggests that the foreshock activity observed in our current experiments was similar to that for the interplate earthquakes in terms of the

  11. First observation of Dorylus ant feeding in Budongo chimpanzees supports absence of stick-tool culture.

    Science.gov (United States)

    Mugisha, Steven; Zuberbühler, Klaus; Hobaiter, Catherine

    2016-07-01

    The use of stick- or probe-tools is a chimpanzee universal, recorded in all long-term study populations across Africa, except one: Budongo, Uganda. Here, after 25 years of observation, stick-tool use remains absent under both natural circumstances and strong experimental scaffolding. Instead, the chimpanzees employ a rich repertoire of leaf-tools for a variety of dietary and hygiene tasks. One use of stick-tools in other communities is in feeding on the aggressive Dorylus 'army ant' species, consumed by chimpanzees at all long-term study sites outside of mid-Western Uganda. Here we report the first observation of army-ant feeding in Budongo, in which individuals from the Waibira chimpanzee community employed detached leaves to feed on a ground swarm. We describe the behaviour and discuss whether or not it can be considered tool use, together with its implication for the absence of stick-tool 'culture' in Budongo chimpanzees.

  12. Sorting it out: bedding particle size and nesting material processing method affect nest complexity.

    Science.gov (United States)

    Robinson-Junker, Amy; Morin, Amelia; Pritchett-Corning, Kathleen; Gaskill, Brianna N

    2017-04-01

    As part of routine husbandry, an increasing number of laboratory mice receive nesting material in addition to standard bedding material in their cages. Nesting material improves health outcomes and physiological performance in mice that receive it. Providing usable nesting material uniformly and efficiently to various strains of mice remains a challenge. The aim of this study was to determine how bedding particle size, method of nesting material delivery, and processing of the nesting material before delivery affected nest building in mice of strong (BALB/cAnNCrl) and weak (C3H/HeNCrl) gathering abilities. Our data suggest that processing nesting material through a grinder in conjunction with bedding material, although convenient for provision of bedding with nesting material 'built-in', negatively affects the integrity of the nesting material and subsequent nest-building outcomes. We also found that C3H mice, previously thought to be poor nest builders, built similarly scored nests to those of BALB/c mice when provided with unprocessed nesting material. This was true even when nesting material was mixed into the bedding substrate. We also observed that when nesting material was mixed into the bedding substrate, mice of both strains would sort their bedding by particle size more often than if it were not mixed in. Our findings support the utility of the practice of distributing nesting material mixed in with bedding substrate, but not that of processing the nesting material with the bedding in order to mix them.

  13. Waffle Production: Influence of Baking Plate Material on Sticking of Waffles.

    Science.gov (United States)

    Huber, Regina; Kalss, Georg; Schoenlechner, Regine

    2017-01-01

    Background of this study was to understand the factors that contribute to sticking of fresh egg waffles on baking plates. The aim of this study was to investigate the sticking (adhesion) behavior of waffles on 4 different baking plate materials (ductile iron, grey iron, low alloyed steel, and steel with titanium nitrite coating) at different baking parameters (temperature and time) and application of 3 different release agents (different fat compositions). Baking plates from ductile and grey iron showed lower release properties of waffles than the 2 steel baking plates. Baking parameters had to be high enough to allow rapid product crust formation but prevent burning, which again increases sticking behavior. Release agents based on short-chain fatty acids with higher degree of saturation provided better release behavior of waffles than those based on long-chain fatty acids or on emulsifier-acid combinations. Baking plates with increased hardness, good heat storage capacity, and smooth surface seemed to be best suitable. Further research on appropriate coating material might be promising for future. © 2016 Institute of Food Technologists®.

  14. Effects of variable sticking coefficients on the stability of reactive sputtering process

    International Nuclear Information System (INIS)

    Li Chuan; Hsieh Janghsing

    2004-01-01

    In reactive sputtering, the introduction of a reactive gas can lead to a hysteresis transition from metal to compounds in both the target and substrate. The hysteresis transition is characterized by a sudden change in partial pressure, sputtering rate, fraction of compound formation, etc. Therefore, stability is an important issue in the process control. In this paper, a mathematical model with variable sticking coefficients based on surface kinetics is used to study the stability of the process. The variable sticking coefficient represents different mechanisms for surface reactions from the Langmuir to precursor type. In order to facilitate the analysis, several nondimensional parameters are identified and used for formulation. Results show that an unsteady system converges to a steady state relatively fast at low inflow rates. With an eigenvalue analysis, the range of positive eigenvalues is consistent with the presence of a hysteresis loop. It is also found that when the chemical reaction on the substrate is moderate, a higher sputter yield of the compound leads to a more stable steady state at lower inflow rates. Regarding the sticking mechanism, for the type of precursors with the parameter k < 1, the compound is easier to form and saturate on the surface due to the higher default sticking coefficient and the lower operating conditions for the hysteresis transition

  15. The Los Alamos Gap Stick Test

    Science.gov (United States)

    Preston, Daniel; Hill, Larry; Johnson, Carl

    2015-06-01

    In this paper we describe a novel shock sensitivity test, the Gap Stick Test, which is a generalized variant of the ubiquitous Gap Test. Despite the popularity of the Gap Test, it has some disadvantages: multiple tests must be fired to obtain a single metric, and many tests must be fired to obtain its value to high precision and confidence. Our solution is a test wherein multiple gap tests are joined in series to form a rate stick. The complex re-initiation character of the traditional gap test is thereby retained, but the propagation speed is steady when measured at periodic intervals, and initiation delay in individual segments acts to decrement the average speed. We measure the shock arrival time before and after each inert gap, and compute the average detonation speed through the HE alone (discounting the gap thicknesses). We perform tests for a range of gap thicknesses. We then plot the aforementioned propagation speed as a function of gap thickness. The resulting curve has the same basic structure as a Diameter Effect (DE) curve, and (like the DE curve) terminates at a failure point. Comparison between experiment and hydrocode calculations using ALE3D and the Ignition and Growth reactive burn model calibrated for short duration shock inputs in PBX 9501 is discussed.

  16. Geometric microliths as chronological and cultural markers in the Sado shell middens? Reflections from Amoreiras (Alcácer do Sal, Portugal

    Directory of Open Access Journals (Sweden)

    Diana Nukushina

    2015-02-01

    Full Text Available The production of geometric microliths from bladelets has been identified as one of the main strategies of lithic production during the Late Mesolithic in southwestern Portugal. The Sado shell middens generally possess an abundance of these tools, similarly to sites found in other regions. However, systematic lithic studies are still scarce. In this work, we discuss the value of the geometric microliths as chronological and cultural markers, through the analysis of lithic remains from Amoreiras shell midden (Alcácer do Sal. First, a formal characterization of this assemblage is performed. Second, a diachronic and cultural perspective of these materials in the Sado shell middens is provided. Finally, a comparison with other Late Mesolithic and the Early Neolithic assemblages from southwestern Iberia is presented. A set of lithic remains from Amoreiras, which was recovered in the 1950s and 1960s, was subject to a techno-typological analysis, following the assumptions of the ‘chaîne opératoire’. Also, a statistical analysis, including variance analysis, was performed. This work shows that the geometric microliths from Amoreiras clearly represent one of the main purposes for the debitage at this site, which presents an outstanding typological and size uniformity. The characteristics found by this study suggest the existence of a well-standardized production of geometric microliths. This production scheme would be more economic in terms of raw material requirements and production time-effort. The material and chronometrical data from Amoreiras contradicts the cultural uniformity perspective for this specific site and for the Sado shell middens in general. Moreover, in light of the presented data, a strict chrono-cultural significance of the segment dominance is difficult to sustain. Despite the standardized production and the importance given to geometric microliths, the data provided by the forms and their variations is still insufficient for

  17. Determination of histamine in milkfish stick implicated in food-borne poisoning

    Directory of Open Access Journals (Sweden)

    Yi-Chen Lee

    2016-01-01

    Full Text Available An incident of food-borne poisoning causing illness in 37 victims due to ingestion of fried fish sticks occurred in September 2014, in Tainan city, southern Taiwan. Leftovers of the victims' fried fish sticks and 16 other raw fish stick samples from retail stores were collected and tested to determine the occurrence of histamine and histamine-forming bacteria. Two suspected fried fish samples contained 86.6 mg/100 g and 235.0 mg/100 g histamine; levels that are greater than the potential hazard action level (50 mg/100 g in most illness cases. Given the allergy-like symptoms of the victims and the high histamine content in the suspected fried fish samples, this food-borne poisoning was strongly suspected to be caused by histamine intoxication. Moreover, the fish species of suspected samples was identified as milkfish (Chanos chanos, using polymerase chain reaction direct sequence analysis. In addition, four of the 16 commercial raw milkfish stick samples (25% had histamine levels greater than the US Food & Drug Administration guideline of 5.0 mg/100 g for scombroid fish and/or products. Ten histamine-producing bacterial strains, capable of producing 373–1261 ppm of histamine in trypticase soy broth supplemented with 1.0% L-histidine, were identified as Enterobacter aerogenes (4 strains, Enterobacter cloacae (1 strain, Morganella morganii (2 strains, Serratia marcescens (1 strain, Hafnia alvei (1 strain, and Raoultella orithinolytica (1 strain, by 16S ribosomal DNA sequencing with polymerase chain reaction amplification.

  18. Effect of the improving teaching method on the prevention of needle stick injuries in the department of infectious disease

    Directory of Open Access Journals (Sweden)

    Yi CHEN

    2014-11-01

    Full Text Available Objective: To discuss the effect of improving teaching method and strengthening the training of occupational protection on the prevention of needle stick injuries in the department of infectious disease. Methods: Collect 17 cases of needle stick injuries that occurred in 2012 among 178 nurses in department of infectious disease. The same cases occurred in 2013 when the nurses had received the occupational protection training and targeted countermeasures were also collected. Results: The incidence of needle stick injuries was 9.55% in infectious department in 2012, and it is down to 3.4% in 2013. Conclusion: Nursing students are more likely to cause needle stick injuries. Training of occupational protection together with nursing technical operation specification can effectively control the occurrence of needle stick injuries.

  19. Measuring sticking and stripping in muon catalyzed dt fusion with multilayer thin films

    International Nuclear Information System (INIS)

    Fujiwara, M.C.; Bailey, J.M.; Beer, G.A.

    1995-12-01

    The authors propose a direct measurement of muon sticking to alpha particles in muon catalyzed dt fusion at a high density. Exploiting the features of a multilayer thin film target developed at TRIUMF, the sticking is determined directly by detection of charged fusion products. Experimental separation of initial ticking and stripping may become possible for the first time. Monte Carlo simulations, as well as preliminary results of test measurements are described

  20. Pre-nesting and nesting behavior of the Swainson's warbler

    Science.gov (United States)

    Meanley, B.

    1969-01-01

    The Swainson?s Warbler is one of the least known of southern birds. Although fairly common in some parts of its summer range, observations of its breeding biology have been made by very few persons. The present study was conducted mostly at Macon, Georgia; Pendleton Ferry, Arkansas; and Dismal Swamp, Virginia....In central Georgia and east-central Arkansas, Swainson?s Warblers usually arrive on their territories during the first two weeks in April. Territories in several localities ranged in size from 0.3 to 4.8 acres. A color-marked Arkansas male occupied the same territory for at least four months. Hostile encounters between territorial male Swainson?s Warblers usually take place along the boundary of adjacent territories. Paired males were more aggressive than unpaired males. Toward the end of an encounter one of the two males would usually perform a display in which the wing and tail feathers were spread and the tail vibrated. Following boundary encounters males drifted back onto their territories and usually sang unbroken courses of songs for several minutes.....During pre-nesting at Macon, a mated pair spent the day mostly on the ground within 20 feet of each other, often foragin g 3 to 4 feet apart. What may have been a form of courtship display, in which the male flew from a perch down to the female and either pecked her rump or pounced on her, occurred about three times each hour throughout the day. During this period the male sang less than at other times during the breeding season.....First nests are usually built by the first week in May. Although other investigators reported finding nests of this species outside of the defended territory, all nests that I have found were within the territory. The large, bulky nest of this species usually is placed 2-6 feet above the ground. It is built by the female from materials gathered close to the nest site; and takes two or three days to complete.....Three and occasionally four white eggs are laid. The female

  1. Open cup nests evolved from roofed nests in the early passerines.

    Science.gov (United States)

    Price, J Jordan; Griffith, Simon C

    2017-02-08

    The architectural diversity of nests in the passerine birds (order Passeriformes) is thought to have played an important role in the adaptive radiation of this group, which now comprises more than half of avian species and occupies nearly all terrestrial ecosystems. Here, we present an extensive survey and ancestral state reconstruction of nest design across the passerines, focusing on early Australian lineages and including members of nearly all passerine families worldwide. Most passerines build open cup-shaped nests, whereas a minority build more elaborate domed structures with roofs. We provide strong evidence that, despite their relative rarity today, domed nests were constructed by the common ancestor of all modern passerines. Open cup nests evolved from enclosed domes at least four times independently during early passerine evolution, at least three of which occurred on the Australian continent, yielding several primarily cup-nesting clades that are now widespread and numerically dominant among passerines. Our results show that the ubiquitous and relatively simple cup-shaped nests of many birds today evolved multiple times convergently, suggesting adaptive benefits over earlier roofed designs. © 2017 The Author(s).

  2. Prediction of Seismic Slope Displacements by Dynamic Stick-Slip Analyses

    International Nuclear Information System (INIS)

    Ausilio, Ernesto; Costanzo, Antonio; Silvestri, Francesco; Tropeano, Giuseppe

    2008-01-01

    A good-working balance between simplicity and reliability in assessing seismic slope stability is represented by displacement-based methods, in which the effects of deformability and ductility can be either decoupled or coupled in the dynamic analyses. In this paper, a 1D lumped mass ''stick-slip'' model is developed, accounting for soil heterogeneity and non-linear behaviour, with a base sliding mechanism at a potential rupture surface. The results of the preliminary calibration show a good agreement with frequency-domain site response analysis in no-slip conditions. The comparison with rigid sliding block analyses and with the decoupled approach proves that the stick-slip procedure can result increasingly unconservative for soft soils and deep sliding depths

  3. Ballasting pipeline moving in horizontal well as method of control sticking phenomenon

    Science.gov (United States)

    Toropov, V. S.; Toropov, E. S.

    2018-05-01

    The mechanism of the phenomenon of sticking a pipeline moving in a well while pulled by the facility horizontal directional drilling is investigated. A quantitative evaluation of the force arising from sticking is given. At the same time, the working hypothesis takes a view of the combined effect of adhesion and friction interactions as the reasons that cause this phenomenon. As a measure to control the occurrence of sticking and to reduce the resistance force to movement of the pipeline in the well, several methods of ballasting the working pipeline are proposed, depending on the profile of the well and the ratio of the length of the curved sections of the inlet and outlet and the straight horizontal sections of the profile. It is shown that for crossings, which profile contains an extended horizontal section, it is possible to partially fill the pipeline with water to achieve zero buoyancy, and for crossings with curvature along the entire profile, the ballasting efficiency will be minimal.

  4. Do Predation Rates on Artificial Nests Accurately Reflect Predation Rates on Natural Bird Nests?

    Science.gov (United States)

    David I. King; Richard M. DeGraaf; Curtice R. Griffin; Thomas J. Maier

    1999-01-01

    Artificial nests are widely used in avian field studies. However, it is unclear how well predation rates on artificial nests reflect predation rates on natural nests. Therefore, we compared survival rates of artificial nests (unused natural nests baited with House Sparrow eggs) with survival rates of active bird nests in the same habitat at the same sites. Survival...

  5. Inertial and stick-slip regimes of unstable adhesive tape peeling.

    Science.gov (United States)

    Dalbe, Marie-Julie; Villey, Richard; Ciccotti, Matteo; Santucci, Stéphane; Cortet, Pierre-Philippe; Vanel, Loïc

    2016-05-18

    We present an experimental characterization of the detachment front unstable dynamics observed during the peeling of pressure sensitive adhesives. We use an experimental set-up specifically designed to control the peeling angle θ and the peeled tape length L, while peeling an adhesive tape from a flat substrate at a constant driving velocity V. High-speed imaging allows us to report the evolution of the period and amplitude of the front oscillations, as well as the relative durations of their fast and slow phases, as a function of the control parameters V, L and θ. Our study shows that, as the driving velocity or the peeling angle increases, the oscillations of the peeling front progressively evolve from genuine "stick-slip" oscillations, made of alternating long stick phases and very brief slip phases, to sinusoidal oscillations of amplitude twice the peeling velocity. We propose a model which, taking into account the peeling angle-dependent kinetic energy cost to accelerate and decelerate the peeled tape, explains the transition from the "stick-slip" to the "inertial" regime of the dynamical instability. Using independent direct measurements of the effective fracture energy of the adhesive-substrate joint, we show that our model quantitatively accounts for the two regimes of the unstable dynamics.

  6. Moxa-stick suffumigation for disinfecting air in hematology and hematopoietic stem cell transplantation wards with class 100 laminar flow.

    Science.gov (United States)

    He, Jing-song; Yang, Qing; Huang, Wei-jia; Hu, Xiao-rong

    2014-04-01

    To evaluate the effect of moxa-stick suffumigation in the hematology and hematopoietic stem cell transplantation (HSCT) wards with luminar flow. The plate exposure method was used to measure the effect of air-disinfection of moxa-stick suffumigation in hematology and HSCT wards. The yearly average qualified rates of air sampling in HSCT wards were evaluated from 2007 to 2010. To further investigate the disinfecting effect of moxa-stick suffumigation, the colony counts of common pathogens (including Staphylcoccus aureus and Pseudomonas aeruginosa) before and after moxa-stick suffumigation were compared. The mean air quality rates of the HSCT wards with class 100 laminar flow were all above 90.0% (91.2%-96.2%) from 2007 to 2010. Moxa-stick suffumigation effectively decreased the presence of bacteria in the hematology ward's air (Pplates exposed to air treated with moxa-stick suffumigation (77.1±52.9 cfu/m(2) vs 196.1±87.5 cfu/m(2), P<0.01; and 100.2±35.3 cfu/m(2) vs 371.5±35.3 cfu/m(2), P<0.01). Moxa-stick suffumigation proved to be a reliable and effective airdisinfection method for hematology and HSCT wards, and hence, it should be employed extensively.

  7. Rapid and specific identification of Yersinia pestis by using a nested polymerase chain reaction procedure.

    OpenAIRE

    Campbell, J; Lowe, J; Walz, S; Ezzell, J

    1993-01-01

    We developed a 4-h nested polymerase chain reaction assay that detected a region of the plasminogen activator gene of Yersinia pestis in 100% of 43 Y. pestis strains isolated from humans, rats, and fleas yet was unreactive with the closely related species Yersinia enterocolitica and Yersinia pseudotuberculosis.

  8. Nest structure and communal nesting in Euglossa (Glossura annectans Dressler (Hymenoptera, Apidae, Euglossini

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Garófalo

    1998-01-01

    Full Text Available Three nests of Euglossa (Glossura annectans Dressier, 1982 were obtained from trap nests at Serra do Japi, Jundiai, São Paulo State, Brazil. The bees nested in bamboo cane (one nest and in wooden-boxes (two nests. Solitary (two cases and pleometrotic (one case foundations were observed. Two nests were re-used once by two females working in each of them. Re-using females that shared the nests were of the same generation and each built, provisioned and oviposited in her own cells, characterizing a communal association. The brood development period was related to climatic conditions. Natural enemies included Anthrax oedipus oedipus Fabricius, 1805 (Bombyliidae, Coelioxys sp. (Megachilidae and Melittobia sp. (Eulophidae.

  9. Hypothenar hammer syndrome from ice hockey stick-handling.

    Science.gov (United States)

    Zayed, Mohamed A; McDonald, Joey; Tittley, Jacques G

    2013-11-01

    Ulnar artery thrombosis and hypothenar hammer syndrome are rare vascular complications that could potentially occur with repeated blows or trauma to the hand. Although initially reported as an occupational hazard among laborers and craftsmen, it has been observed more recently among recreationalists and athletes. Until now, it has never been reported as a complication in ice hockey players. In this case report, a 26-year-old Canadian professional ice hockey player presented with acute dominant right hand paleness, coolness, and pain with hand use. The patient used a wooden hockey stick with a large knob of tape at the end of the handle, which he regularly gripped in the palm of his right hand to help with face-offs and general stick-handling. Sonographic evaluation demonstrated no arterial flow in the distal right ulnar artery distribution, and ulnar artery occlusion with no aneurysmal degeneration was confirmed by magnetic resonance angiogram. Intraarterial thrombolytic therapy was initiated, and subsequent serial angiograms demonstrated significant improvement in distal ulnar artery flow as well as recanalization of right hand deep palmar arch and digital arteries. The patient's symptoms resolved, and he was maintained on therapeutic anticoagulation for 3 months prior to returning to playing ice hockey professionally, but with a padded glove and no tape knob at the handle tip. This case highlights a unique presentation of hockey stick-handling causing ulnar artery thrombosis that was likely from repeated palmar hypothenar trauma. Appropriate diagnostic imaging, early intraarterial thrombolysis, and postoperative surveillance and follow-up were crucial for the successful outcome in this patient. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Cultural Adaptation of the Portuguese Version of the "Sniffin' Sticks" Smell Test: Reliability, Validity, and Normative Data.

    Science.gov (United States)

    Ribeiro, João Carlos; Simões, João; Silva, Filipe; Silva, Eduardo D; Hummel, Cornelia; Hummel, Thomas; Paiva, António

    2016-01-01

    The cross-cultural adaptation and validation of the Sniffin`Sticks test for the Portuguese population is described. Over 270 people participated in four experiments. In Experiment 1, 67 participants rated the familiarity of presented odors and seven descriptors of the original test were adapted to a Portuguese context. In Experiment 2, the Portuguese version of Sniffin`Sticks test was administered to 203 healthy participants. Older age, male gender and active smoking status were confirmed as confounding factors. The third experiment showed the validity of the Portuguese version of Sniffin`Sticks test in discriminating healthy controls from patients with olfactory dysfunction. In Experiment 4, the test-retest reliability for both the composite score (r71 = 0.86) and the identification test (r71 = 0.62) was established (pPortuguese version of Sniffin`Sticks test is provided, showing good validity and reliability and effectively distinguishing patients from healthy controls with high sensitivity and specificity. The Portuguese version of Sniffin`Sticks test identification test is a clinically suitable screening tool in routine outpatient Portuguese settings.

  11. Effect of heterogeneity of nest boxes on occurrence of gregarious nesting in laying hens

    DEFF Research Database (Denmark)

    Clausen, Tina; Riber, Anja Brinch

    2012-01-01

    Gregarious nesting, where hens select already occupied nest boxes even when other nest boxes are unoccupied, is an unwanted behaviour in laying hens that may reduce animal welfare and pose a financial cost to the producer. It has been suggested that gregarious nesting is caused by the difficulties...... nesting was higher in experimental groups compared to control groups (P right were higher compared to nest boxes positioned...

  12. Slip-stick excitation and travelling waves excite silo honking

    Science.gov (United States)

    Warburton, Katarzyna; Porte, Elze; Vriend, Nathalie

    2017-06-01

    Silo honking is the harmonic sound generated by the discharge of a silo filled with a granular material. In industrial storage silos, the acoustic emission during discharge of PET-particles forms a nuisance for the environment and may ultimately result in structural failure. This work investigates the phenomenon experimentally using a laboratory-scale silo, and successfully correlates the frequency of the emitted sound with the periodicity of the mechanical motion of the grains. The key driver is the slip-stick interaction between the wall and the particles, characterized as a wave moving upwards through the silo. A quantitative correlation is established for the first time between the frequency of the sound, measured with an electret microphone, and the slip-frequency, measured with a high-speed camera. In the lower regions of the tube, both the slip-stick motion and the honking sound disappear.

  13. A geophone wireless sensor network for investigating glacier stick-slip motion

    Science.gov (United States)

    Martinez, Kirk; Hart, Jane K.; Basford, Philip J.; Bragg, Graeme M.; Ward, Tyler; Young, David S.

    2017-08-01

    We have developed an innovative passive borehole geophone system, as part of a wireless environmental sensor network to investigate glacier stick-slip motion. The new geophone nodes use an ARM Cortex-M3 processor with a low power design capable of running on battery power while embedded in the ice. Only data from seismic events was stored, held temporarily on a micro-SD card until they were retrieved by systems on the glacier surface which are connected to the internet. The sampling rates, detection and filtering levels were determined from a field trial using a standard commercial passive seismic system. The new system was installed on the Skalafellsjökull glacier in Iceland and provided encouraging results. The results showed that there was a relationship between surface melt water production and seismic event (ice quakes), and these occurred on a pattern related to the glacier surface melt-water controlled velocity changes (stick-slip motion). Three types of seismic events were identified, which were interpreted to reflect a pattern of till deformation (Type A), basal sliding (Type B) and hydraulic transience (Type C) associated with stick-slip motion.

  14. Stick-slip chaos in a mechanical oscillator with dry friction

    Science.gov (United States)

    Kousaka, Takuji; Asahara, Hiroyuki; Inaba, Naohiko

    2018-03-01

    This study analyzes a forced mechanical dynamical system with dry friction that can generate chaotic stick-slip vibrations. We find that the dynamics proposed by Yoshitake et al. [Trans. Jpn. Soc. Mech. Eng. C 61, 768 (1995)] can be expressed as a nonautonomous constraint differential equation owing to the static friction force. The object is constrained to the surface of a moving belt by a static friction force from when it sticks to the surface until the force on the object exceeds the maximal static friction force. We derive a 1D Poincaré return map from the constrained mechanical system, and prove numerically that this 1D map has an absolutely continuous invariant measure and a positive Lyapunov exponent, providing strong evidence for chaos.

  15. Nest predation increases with parental activity: separating nest site and parental activity effects.

    OpenAIRE

    Martin, T E; Scott, J; Menge, C

    2000-01-01

    Alexander Skutch hypothesized that increased parental activity can increase the risk of nest predation. We tested this hypothesis using ten open-nesting bird species in Arizona, USA. Parental activity was greater during the nestling than incubation stage because parents visited the nest frequently to feed their young during the nestling stage. However, nest predation did not generally increase with parental activity between nesting stages across the ten study species. Previous investigators h...

  16. R.E.A.C.H. to Teach: Making Patient and Family Education "Stick".

    Science.gov (United States)

    Cutilli, Carolyn Crane

    2016-01-01

    Healthcare professionals teach patients and families about their health every day. Regulatory and accreditation organizations mandate patient and family education to promote better health outcomes. And recently, financial rewards for healthcare organizations are being tied to patient satisfaction (Hospital Consumer Assessment of Healthcare Providers and Systems-HCAHPS). A University of Pennsylvania Health System group of staff and patients, devoted to excellence in patient and family education, developed the graphic "R.E.A.C.H. to Teach." The purpose of the graphic is to make evidence-based practice (EBP) for patient and family education "stick" with staff. The group used concepts from the marketing book, Made to Stick, to demonstrate how to develop effective staff and patient and family education. Ideas (education) that survive ("stick") have the following attributes: simple, unexpected, concrete, credible, emotional, and narrative (story). This article demonstrates how to apply these principles and EBP to patient and family education.

  17. Short stick exercises for fall prevention among older adults: a cluster randomized trial.

    Science.gov (United States)

    Yokoi, Katsushi; Yoshimasu, Kouichi; Takemura, Shigeki; Fukumoto, Jin; Kurasawa, Shigeki; Miyashita, Kazuhisa

    2015-01-01

    To investigate the effects of short stick exercise (SSEs) on fall prevention and improvement of physical function in older adults. A cluster randomized trial was conducted in five residential care facilities. The intervention group (n = 51) practiced SSEs for six months, followed by routine care for six more months. The control group (n = 54) received ordinary care for 12 months. The primary outcome measure was the number of fallers, taking into account the time to first fall using the Kaplan-Meier method. The secondary outcome measures were physical and mental functions. The number of fallers was significantly lower in the intervention group (n = 6) than in the control group (n = 16) during the 12 months. The adjusted hazard ratio for a first fall in the intervention group compared with the control group was 0.15 (CI, 0.03 to 0.74, p = 0.02). The fall-free period was significantly longer in the intervention group than in controls (mean ± SD, 10.1 ± 3.0 versus 9.0 ± 4.1 months, p = 0.027). The functional reach and sit and reach tests were significantly improved at three and six months. The SSEs appeared effective for fall prevention and improvement of physical function in older adults. Implications for Rehabilitation The newly developed short stick exercises appear an effective means of reducing falls among older adults in residential care facilities. The short stick exercises seem to have an immediate effect on improving physical functions. Effects gained by performing the short stick exercises, such as static balance, flexibility and agility may last for six months. The short stick exercises were found to be easy for older adults to practice continuously in residential care facilities.

  18. Investigation of PDC bit failure base on stick-slip vibration analysis of drilling string system plus drill bit

    Science.gov (United States)

    Huang, Zhiqiang; Xie, Dou; Xie, Bing; Zhang, Wenlin; Zhang, Fuxiao; He, Lei

    2018-03-01

    The undesired stick-slip vibration is the main source of PDC bit failure, such as tooth fracture and tooth loss. So, the study of PDC bit failure base on stick-slip vibration analysis is crucial to prolonging the service life of PDC bit and improving ROP (rate of penetration). For this purpose, a piecewise-smooth torsional model with 4-DOF (degree of freedom) of drilling string system plus PDC bit is proposed to simulate non-impact drilling. In this model, both the friction and cutting behaviors of PDC bit are innovatively introduced. The results reveal that PDC bit is easier to fail than other drilling tools due to the severer stick-slip vibration. Moreover, reducing WOB (weight on bit) and improving driving torque can effectively mitigate the stick-slip vibration of PDC bit. Therefore, PDC bit failure can be alleviated by optimizing drilling parameters. In addition, a new 4-DOF torsional model is established to simulate torsional impact drilling and the effect of torsional impact on PDC bit's stick-slip vibration is analyzed by use of an engineering example. It can be concluded that torsional impact can mitigate stick-slip vibration, prolonging the service life of PDC bit and improving drilling efficiency, which is consistent with the field experiment results.

  19. Paleomadrigueras de roedores, un nuevo método para el estudio del Cuaternario en zonas áridas de Sudamérica Rodent middens, a new method for Quaternary research in arid zones of South America

    Directory of Open Access Journals (Sweden)

    Julio L. Betancourt

    2002-09-01

    formadores. Basados en la experiencia Norteamericana entregamos además, un resumen de los métodos existentes para la detección y análisis de dichos depósitos, los sesgos asociados, así como el aporte potencial que su análisis podría representar en futuros estudios paleoecológicos en las zonas áridas y semiáridas de SudaméricaIn arid and semi-arid regions of South America, historical evidence for climate and vegetation change is scarce despite its importance for determining reference conditions and rates of natural variability in areas susceptible to modern desertification. Normal lines of evidence, such as pollen stratigraphies from lakes, are either rare or unobtainable in deserts; studies of late Quaternary vegetation history are few and generally inconclusive. This gap in knowledge may be corrected with discovery and development of fossil rodent middens in rocky environments throughout arid South America. These middens, mostly the work of Lagidium, Phyllotis, Abrocoma and Octodontomys, are rich in readily identifiable plant macrofossils, cuticles and pollen, as well as vertebrate and insect remains. In the North American deserts, more than 2,500 woodrat (Neotoma middens analyzed since 1960 have yielded a detailed history of environmental change during the past 40,000 years. Preliminary work in the pre-puna, Monte and Patagonian Deserts of western Argentina, the Atacama Desert of northern Chile/southern Peru, the Mediterranean matorral of central Chile, and the Puna of the Andean altiplano suggest a similar potential for rodent middens in South America. Here we borrow from the North American experience to synthesize methodologies and approaches, summarize preliminary work, and explore the potential of rodent midden research in South America

  20. Evidence for Ventilation through Collective Respiratory Movements in Giant Honeybee (Apis dorsata) Nests.

    Science.gov (United States)

    Kastberger, Gerald; Waddoup, Dominique; Weihmann, Frank; Hoetzl, Thomas

    2016-01-01

    The Asian giant honeybees (Apis dorsata) build single-comb nests in the open, which makes this species particularly susceptible to environmental strains. Long-term infrared (IR) records documented cool nest regions (CNR) at the bee curtain (nCNR = 207, nnests > 20) distinguished by marked negative gradients (ΔTCNR/d 0) displaying the Venturi effect, which evidences funnel properties of CNRs. The air flows inwards through CNRs, which is verified by the negative spatial gradient ΔTCNR/d, by the positive grading of TCNR with Tamb and lastly by fanners which have directed their abdomens towards CNRs. Rare cases of RAT +0.4 cm2/s) displaying "inhalation" and "exhalation" cycling. "Inhalation" could be boosted by bees at the inner curtain layers, which stretch their extremities against the comb enlarging the inner nest lumen and thus causing a pressure fall which drives ambient air inwards through CNR funnels. The relaxing of the formerly "activated" bees could then trigger the "exhalation" process, which brings the bee curtain, passively by gravity, close to the comb again. That way, warm, CO2-enriched nest-borne air is pressed outwards through the leaking mesh of the bee curtain. This ventilation hypothesis is supported by IR imaging and laser vibrometry depicting CNRs in at least four aspects as low-resistance convection funnels for maintaining thermoregulation and restoring fresh air in the nest.

  1. Evidence for Ventilation through Collective Respiratory Movements in Giant Honeybee (Apis dorsata Nests.

    Directory of Open Access Journals (Sweden)

    Gerald Kastberger

    Full Text Available The Asian giant honeybees (Apis dorsata build single-comb nests in the open, which makes this species particularly susceptible to environmental strains. Long-term infrared (IR records documented cool nest regions (CNR at the bee curtain (nCNR = 207, nnests > 20 distinguished by marked negative gradients (ΔTCNR/d 0 displaying the Venturi effect, which evidences funnel properties of CNRs. The air flows inwards through CNRs, which is verified by the negative spatial gradient ΔTCNR/d, by the positive grading of TCNR with Tamb and lastly by fanners which have directed their abdomens towards CNRs. Rare cases of RAT +0.4 cm2/s displaying "inhalation" and "exhalation" cycling. "Inhalation" could be boosted by bees at the inner curtain layers, which stretch their extremities against the comb enlarging the inner nest lumen and thus causing a pressure fall which drives ambient air inwards through CNR funnels. The relaxing of the formerly "activated" bees could then trigger the "exhalation" process, which brings the bee curtain, passively by gravity, close to the comb again. That way, warm, CO2-enriched nest-borne air is pressed outwards through the leaking mesh of the bee curtain. This ventilation hypothesis is supported by IR imaging and laser vibrometry depicting CNRs in at least four aspects as low-resistance convection funnels for maintaining thermoregulation and restoring fresh air in the nest.

  2. The nest as fortress: Defensive behavior of Polybia emaciata, a mud-nesting eusocial wasp

    Directory of Open Access Journals (Sweden)

    Sean O'Donnell

    2002-02-01

    Full Text Available The swarm-founding wasp Polybia emaciata is unusual among eusocial Vespidae because it uses mud, rather than wood pulp, as its primary nest construction material. Polybia emaciata nests are more durable than similarly sized paper nests. We tested the hypothesis that the defensive behavior of this wasp may have been modified to take advantage of their strong nests in defense against vertebrate attacks. We simulated vertebrate disturbances by tapping on, and breathing in, P. emaciata. nests and similarly sized P. occidentalis paper nests in the same location at the same time. Polybia emaciata. responses to disturbance were qualitatively different from those of P. occidentalis. The latter exit the nest and attack, while P. emaciata. workers typically fled or entered the nest, attacking only after repeated and extended disturbances. We conclude that durable nest material may permit predator avoidance behavior in P. emaciata.. We compare the defensive responses of P. emaciata. workers with those of other swarm-founding Vespidae, and discuss several selective forces that could cause the evolution of species variation in nest defense behavior.

  3. Cavity Nesting Birds

    Science.gov (United States)

    Virgil E. Scott; Keith E. Evans; David R. Patton; Charles P. Stone

    1977-01-01

    Many species of cavity-nesting birds have declined because of habitat reduction. In the eastern United States, where primeval forests are gone, purple martins depend almost entirely on man-made nesting structures (Allen and Nice 1952). The hole-nesting population of peregrine falcons disappeared with the felling of the giant trees upon which they depended (Hickey and...

  4. Nest predators of open and cavity nesting birds in oak woodlands

    Science.gov (United States)

    Kathryn L. Purcell; Jared Verner

    1999-01-01

    Camera setups revealed at least three species of rodents and seven species of birds as potential predators at artificial open nests. Surprisingly, among avian predators identified at open nests, one third were Bullock's Orioles (Icterus bullockii). Two rodent species and three bird species were potential predators at artificial cavity nests. This high predator...

  5. Modeling nest survival of cavity-nesting birds in relation to postfire salvage logging

    Science.gov (United States)

    Vicki Saab; Robin E. Russell; Jay Rotella; Jonathan G. Dudley

    2011-01-01

    Salvage logging practices in recently burned forests often have direct effects on species associated with dead trees, particularly cavity-nesting birds. As such, evaluation of postfire management practices on nest survival rates of cavity nesters is necessary for determining conservation strategies. We monitored 1,797 nests of 6 cavity-nesting bird species: Lewis'...

  6. Development of low energy electron beam irradiation techniques. Application to sticking adhesive

    International Nuclear Information System (INIS)

    Ito, Hisashi; Enomoto, Ichiro

    1997-01-01

    Sticking adhesives were developed by use of blend with electron beam crosslinked type stylene - isoprene block copolymer (SIS) as a basic component. The sticking adhesive has object to change from sticking to adhesion and peeling by irradiation. SIS was blended with reactive monomer and resins or alicyclic hydrocarbon as tackifier and investigated. The results showed change of peel force by irradiation was influenced by compatibility, composition and the quality of objective materials. SIS such as Kraton D1320X (Shell Co. Ltd.) and tackifier such as rosin (ROSIN) and arcone P100 (ARP) were used at the basic ratio SIS/tackifier=64. Modified urethane acrylate (UA306H), isobornyl acrylate (IBXA), epoxy ester (3002M), lauryl methacrylate (LM) and lauryl acrylate (LA) were used as monomer. The large changes of peel force were observed by blends with UA306H or 3002M of which properties were incompatibility. These results indicated that we made possible to control the peel force by irradiation by means of adding the specific incompatibility monomer to the mixture of SIS and tackifier. (S.Y.)

  7. Triangular Nests!

    Science.gov (United States)

    Powell, R. I.

    2002-01-01

    Shows how integer-sided triangles can be nested, each nest having a single enclosing isosceles triangle. Brings to light what can be seen as a relatively simple generalization of Pythagoras' theorem, a result that should be readily accessible to many secondary school pupils. (Author/KHR)

  8. Slip-stick excitation and travelling waves excite silo honking

    Directory of Open Access Journals (Sweden)

    Warburton Katarzyna

    2017-01-01

    Full Text Available Silo honking is the harmonic sound generated by the discharge of a silo filled with a granular material. In industrial storage silos, the acoustic emission during discharge of PET-particles forms a nuisance for the environment and may ultimately result in structural failure. This work investigates the phenomenon experimentally using a laboratory-scale silo, and successfully correlates the frequency of the emitted sound with the periodicity of the mechanical motion of the grains. The key driver is the slip-stick interaction between the wall and the particles, characterized as a wave moving upwards through the silo. A quantitative correlation is established for the first time between the frequency of the sound, measured with an electret microphone, and the slip-frequency, measured with a high-speed camera. In the lower regions of the tube, both the slip-stick motion and the honking sound disappear.

  9. Nest-site habitat of cavity-nesting birds at the San Joaquin Experimental Range

    Science.gov (United States)

    Kathryn L. Purcell; Jared. Verner

    2008-01-01

    Detailed information about the nesting habitats of birds, including those needed for successful nesting, can provide a better understanding of the ecological factors that permit coexistence of different species and may aid in conservation efforts. From 1989 through 1994, we studied the nesting habitat of secondary cavity-nesting birds in oak woodlands at the San...

  10. Spawning chronology, nest site selection and nest success of smallmouth bass during benign streamflow conditions

    Science.gov (United States)

    Dauwalter, D.C.; Fisher, W.L.

    2007-01-01

    We documented the nesting chronology, nest site selection and nest success of smallmouth bass Micropterus dolomieu in an upstream (4th order) and downstream (5th order) reach of Baron Fork Creek, Oklahoma. Males started nesting in mid-Apr. when water temperatures increased to 16.9 C upstream, and in late-Apr. when temperatures increased to 16.2 C downstream. Streamflows were low (77% upstream to 82% downstream of mean Apr. streamflow, and 12 and 18% of meanjun. streamflow; 47 and 55 y of record), and decreased throughout the spawning period. Larger males nested first upstream, as has been observed in other populations, but not downstream. Upstream, progeny in 62 of 153 nests developed to swim-up stage. Downstream, progeny in 31 of 73 nests developed to swim-up. Nesting densities upstream (147/km) and downstream (100/km) were both higher than any densities previously reported. Males selected nest sites with intermediate water depths, low water velocity and near cover, behavior that is typical of smallmouth bass. Documented nest failures resulted from human disturbance, angling, and longear sunfish predation. Logistic exposure models showed that water velocity at the nest was negatively related and length of the guarding male was positively related to nest success upstream. Male length and number of degree days were both positively related to nest success downstream. Our results, and those of other studies, suggest that biological factors account for most nest failures during benign (stable, low flow) streamflow conditions, whereas nest failures attributed to substrate mobility or nest abandonment dominate when harsh streamflow conditions (spring floods) coincide with the spawning season.

  11. Cavity-nesting bird use of nest boxes in vineyards of central-coast California

    Science.gov (United States)

    Daniel P. Mummert; Laura Baines; William D. Tietje

    2002-01-01

    Oak woodland habitat is being degraded or replaced by vineyards in many areas of central-coastal California. Oak woodlands are home to many insectivorous, cavity-nesting birds that would be beneficial in and around vineyards. During March to June 2001, we used bluebird nest boxes to study nest box use and productivity of cavity-nesting birds in vineyards versus...

  12. Cigarette stick as valuable communicative real estate: a content analysis of cigarettes from 14 low-income and middle-income countries.

    Science.gov (United States)

    C Smith, Katherine; Washington, Carmen; Welding, Kevin; Kroart, Laura; Osho, Adami; Cohen, Joanna E

    2016-09-01

    The current cigarette market is heavily focused on low-income and middle-income countries. Branding of tobacco products is key to establishing and maintaining a customer base. Greater restrictions on marketing and advertising of tobacco products create an incentive for companies to focus more on branding via the product itself. We consider how tobacco sticks are used for communicative purposes in 14 low-income and middle-income countries with extensive tobacco markets. In 2013, we collected and coded 3232 cigarette and kretek packs that were purchased from vendors in diverse neighbourhoods in 44 cities across the 14 low-income and middle-income countries with the greatest number of smokers. A single stick from each pack was assessed for branding, decorative and communicative elements using a common coding framework. Stick communication variables included brand name, brand image/logo, brand descriptor, colour and design carried through from pack, 'capsule cigarette' symbol, and embellishment of filter end. Communication and branding on the stick is essentially ubiquitous (99.75%); 97% of sticks include explicit branding (brand name or logo present). Colour is commonly carried through from the pack (95%), and some sticks (13%) include decorative elements matching the pack. Decorative elements can be found anywhere on the stick, including the filter tip (8%), and 'convertible' cigarettes include a symbol to show where to push. Cigarette sticks are clearly valuable 'real estate' that tobacco companies are using for communicative purposes. Across all countries and brands, the stick communicates branding via text, colour and imagery. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  13. Livestock grazing and trampling of birds' nests: An experiment using artificial nests

    OpenAIRE

    Mandema, Freek S.; Tinbergen, Joost M.; Ens, Bruno J.; Bakker, Jan P.

    2013-01-01

    The purpose of this study is to experimentally determine the differences between four grazing treatments on the trampling of nests. Additionally, we examine to what extent the trampling probability of nests is higher close to a source of fresh water. We compare the trampling of artificial nests in five different grazing treatments in an experimental design. We use buried clay pigeon targets as artificial mimics of bird nests to obtain reliable estimates of trampling risk and compare these wit...

  14. A study of needle stick injuries among non-consultant hospital doctors in Ireland.

    LENUS (Irish Health Repository)

    O'Connor, M B

    2012-02-01

    INTRODUCTION: NCHDs are exposed to a great number of blood-borne infections. Needle stick injuries are possibly the main route of acquiring such infections from a non-consultant hospital doctors (NCHDs) perspective. This study examines NCHDs experiences surrounding needle stick injuries. METHODS: A cross-sectional self-administered anonymous questionnaire survey was conducted on 185 NCHDs working in a clinical setting among seven teaching hospitals in Ireland. Implied consent was obtained. The data was analysed using Excel spreadsheets. Ethical approval was received. RESULTS: A response rate of 85.4% (158\\/185) was achieved. Findings of the study are shown in the manuscript table. CONCLUSIONS: A needle stick injury (NI) history is greater among surgical NCHDs than medical NCHDs. The level of disposable glove usage is worryingly poor. Training in sharps handling and dealing with a NI needs to be addressed. HIV is the blood-borne infection most fear of being contracting as a consequence of a NI.

  15. Flown The Nest

    OpenAIRE

    Sebbane, Nathalie

    2012-01-01

    Lorsque le quotidien régional, The Champion, commence à publier Flown The Nest en 1972 sous forme d’épisodes, Bird’s Nest Soup est déjà en vente, et la troisième partie de l’autobiographie d’Hanna, Housekeeper At Large, est sous presse. L’édition de 2009 contient Flown The Nest et Housekeeper at Large. Dans Bird’s Nest Soup, Hanna Greally racontait les dix-huit années de sa vie passées au sein d’un hôpital psychiatrique. Les raisons pour lesquelles elle y avait été enfermée, à la demande de s...

  16. Sustained frictional instabilities on nanodomed surfaces: Stick-slip amplitude coefficient

    DEFF Research Database (Denmark)

    Quignon, Benoit; Pilkington, Georgia A.; Thormann, Esben

    2013-01-01

    to sustained frictional instabilities, effectively with no contact frictional sliding. The amplitude of the stick-slip oscillations, σf, was found to correlate with the topographic properties of the surfaces and scale linearly with the applied load. In line with the friction coefficient, we define the slope......-defined nanodomes comprising densely packed prolate spheroids, of diameters ranging from tens to hundreds of nanometers. Our results show that the average lateral force varied linearly with applied load, as described by Amontons' first law of friction, although no direct correlation between the sample topographic...... properties and their measured friction coefficients was identified. Furthermore, all the nanodomed textures exhibited pronounced oscillations in the shear traces, similar to the classic stick-slip behavior, under all the shear velocities and load regimes studied. That is, the nanotextured topography led...

  17. On the stick-slip vibration in the suspension of a freight wagon

    Directory of Open Access Journals (Sweden)

    Mazilu Traian

    2017-01-01

    Full Text Available Damping based on the dry friction is frequently in suspensions of the freight wagons. The paper presents some aspects of vertical vibration of freight wagons. It uses a simple model considering that the vehicle was reduced to a mass suspended on a wheel, moving at constant speed on a rigid track with harmonic irregularity. Stick-slip vibration can occur due to the friction and it is characterized by sudden changes in the wheel acceleration affecting the ride quality. The paper shows the influence of stick-slip vibration on the wheel-rail dynamic force.

  18. New non-stick expoxy-silicone water-based coatings part 1: Physical and surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Garti, N. [Hebrew Univ. of Jerusalem (Israel); Smith, J. [Decora Manufacturing, Fort Edward, NY (United States)

    1995-06-01

    In search for tomorrow`s technology for water-based coating, Decora Manufacturing and The Hebrew University of Jerusalem, have initiated an intensive research program for designing, developing and manufacturing new coatings based on cross-linked, room temperature-cured silicone-expoxy resins. The new water-borne coatings have most exciting characteristics such as: non-stick properties, effective release, high lubricity, corrosion protection and abrasion resistance. The coatings are environmentally-friendly and easy to use. These coatings are ideal for marine, agricultural, industrial and maintenance applications. This paper brings quantitative measurements related to the dispersion technology (particle size, stability, shelf-life), to the non-stick properties (deicing, low surface energy, easy-release and non-stick), lubricity, adhesion to substrates, viscosity, dynamic and static friction coefficients and environmental impact (low VOC, non-toxicity, low-leaching). The coating was tested in various industrial coating systems and was found to exhibit excellent non-stick and release properties. Special attention was given to Zebra Mussels, Quagga Mussels and other bacterial and algeal bioforms. The coating proved to be efficient as foul-release coating with very low biofouling adhesion. The low adhesion applied to many other substances in which foul-release means easy-clean and low-wear.

  19. Electrical Potentials Observed During Frictional Stick-Slip - A Semiconductor Mechanism

    Science.gov (United States)

    Leeman, J.; Scuderi, M.; Marone, C.; Saffer, D. M.

    2013-12-01

    Electromagnetic phenomena are commonly reported during and after large earthquakes. Various lines of evidence including charring of plant roots, magnetic remnant signatures in pseudotachylite, and visible earthquake lights indicate a strong electrical potential separation during co-seismic rupture. Suggested explanations have included triboelectricity, piezoelectricity, and streaming potentials. The 'semiconductor effect', or migration of electron holes, has been proposed as an alternative explanation and studied extensively in solids. We present evidence of a similar migration effect in a granular material that exhibits repeated frictional stick-slip events under a variety of conditions. Soda-lime glass beads were sheared in a double-direct shear configuration in a biaxial loading frame. Glass beads exhibit consistent, repetitive stick-slip and rate/state friction effects that are similar to rock. Layers of 5 mm thickness were sheared under a constant normal load of 4MPa, at load point velocities of 1, 30, and 100 μm/s. This was done for mono-disperse particle size distributions of 100-150 μm and 420-500 μm. Tests were conducted at room humidity, at 100% humidity, and under submerged conditions. During shearing, the electrical potential of the surface was monitored relative to the system ground with a non-contact electrostatic volt meter (ESVM) manufactured by Trek Incorporated. During stick-slip events, we observe electrical potential anomalies that appear to be related to failure of force chains supporting the shear load. Two distinct types of behavior are delineated by the attainment of steady state frictional sliding. In the pre-steady state phase, as shear stress is increasing, layers are observed to charge during stick-slip and the potential of the entire system rises. When shear stress rises to the level of steady state frictional sliding, the system begins to discharge, with superimposed anomalies characterized by potential drops of several volts that

  20. From neurons to nests: nest-building behaviour as a model in behavioural and comparative neuroscience.

    Science.gov (United States)

    Hall, Zachary J; Meddle, Simone L; Healy, Susan D

    Despite centuries of observing the nest building of most extant bird species, we know surprisingly little about how birds build nests and, specifically, how the avian brain controls nest building. Here, we argue that nest building in birds may be a useful model behaviour in which to study how the brain controls behaviour. Specifically, we argue that nest building as a behavioural model provides a unique opportunity to study not only the mechanisms through which the brain controls behaviour within individuals of a single species but also how evolution may have shaped the brain to produce interspecific variation in nest-building behaviour. In this review, we outline the questions in both behavioural and comparative neuroscience that nest building could be used to address, summarize recent findings regarding the neurobiology of nest building in lab-reared zebra finches and across species building different nest structures, and suggest some future directions for the neurobiology of nest building.

  1. Avoiding the nest : responses of field sparrows to the threat of nest predation

    Science.gov (United States)

    Dirk E. Burhans

    2000-01-01

    Nest predation is a major source of reproductive failure in birds (Ricklefs 1969, Martin 1992). Birds confronted with an enemy near the nest may use behaviors to deter the prospect of nest predation. The benefits of nest defense have been shown for many agressive species (Martin 1992), but smaller birds that cannot deter predators may need to resort to other behaviors...

  2. IE Information Notice No. 85-17, Supplement 1: Possible sticking of ASCO solenoid valves

    International Nuclear Information System (INIS)

    Jordan, E.L.

    1992-01-01

    This notice is to inform recipients of the results of follow up investigations regarding the reasons for sticking of Automatic Switch Company (ASCO) solenoid valves used to shut main steam isolation valves (MSIVs) under accident conditions. GE has recommend that the licensee replace the potentially contaminated MSIV solenoid valves and institute a periodic examination and cleaning of the MSIV solenoid valves. Grand Gulf has replaced the eight MSIV HTX832320V dual solenoid valves with fully environmentally qualified ASCO Model NP 8323A20E dual solenoid valves. The environmentally qualified valve Model NP 8323A20E was included in a control sample placed in the test ovens with the solenoid valves that stuck at Grand Gulf. The environmentally qualified model did not stick under the test conditions that cause sticking in the other solenoid valves

  3. Using Artificial Nests to Study Nest Predation in Birds

    Science.gov (United States)

    Belthoff, James R.

    2005-01-01

    A simple and effective field exercise that demonstrates factors affecting predation on bird nests is described. With instructor guidance, students in high school biology or college-level biology, ecology, animal behavior, wildlife management or ornithology laboratory courses can collaborate to design field experiments related to nest depredation.

  4. Livestock grazing and trampling of birds' nests : An experiment using artificial nests

    NARCIS (Netherlands)

    Mandema, Freek S.; Tinbergen, Joost M.; Ens, Bruno J.; Bakker, Jan P.

    The purpose of this study is to experimentally determine the differences between four grazing treatments on the trampling of nests. Additionally, we examine to what extent the trampling probability of nests is higher close to a source of fresh water. We compare the trampling of artificial nests in

  5. Nested and Hierarchical Archimax copulas

    KAUST Repository

    Hofert, Marius

    2017-07-03

    The class of Archimax copulas is generalized to nested and hierarchical Archimax copulas in several ways. First, nested extreme-value copulas or nested stable tail dependence functions are introduced to construct nested Archimax copulas based on a single frailty variable. Second, a hierarchical construction of d-norm generators is presented to construct hierarchical stable tail dependence functions and thus hierarchical extreme-value copulas. Moreover, one can, by itself or additionally, introduce nested frailties to extend Archimax copulas to nested Archimax copulas in a similar way as nested Archimedean copulas extend Archimedean copulas. Further results include a general formula for the density of Archimax copulas.

  6. Nested and Hierarchical Archimax copulas

    KAUST Repository

    Hofert, Marius; Huser, Raphaë l; Prasad, Avinash

    2017-01-01

    The class of Archimax copulas is generalized to nested and hierarchical Archimax copulas in several ways. First, nested extreme-value copulas or nested stable tail dependence functions are introduced to construct nested Archimax copulas based on a single frailty variable. Second, a hierarchical construction of d-norm generators is presented to construct hierarchical stable tail dependence functions and thus hierarchical extreme-value copulas. Moreover, one can, by itself or additionally, introduce nested frailties to extend Archimax copulas to nested Archimax copulas in a similar way as nested Archimedean copulas extend Archimedean copulas. Further results include a general formula for the density of Archimax copulas.

  7. Nest site characteristics, nesting movements, and lack of long-term nest site fidelity in Agassiz's desert tortoises at a wind energy facility in southern California

    Science.gov (United States)

    Lovich, Jeffrey E.; Agha, Mickey; Yackulic, Charles B.; Meyer-Wilkins, Kathie; Bjurlin, Curtis; Ennen, Joshua R.; Arundel, Terry R.; Austin, Meaghan

    2014-01-01

    Nest site selection has important consequences for maternal and offspring survival and fitness. Females of some species return to the same nesting areas year after year. We studied nest site characteristics, fidelity, and daily pre-nesting movements in a population of Agassiz’s desert tortoises (Gopherus agassizii) at a wind energy facility in southern California during two field seasons separated by over a decade. No females returned to the same exact nest site within or between years but several nested in the same general area. However, distances between first and second clutches within a year (2000) were not significantly different from distances between nests among years (2000 and 2011) for a small sample of females, suggesting some degree of fidelity within their normal activity areas. Environmental attributes of nest sites did not differ significantly among females but did among years due largely to changes in perennial plant structure as a result of multiple fires. Daily pre-nesting distances moved by females decreased consistently from the time shelled eggs were first visible in X-radiographs until oviposition, again suggesting some degree of nest site selection. Tortoises appear to select nest sites that are within their long-term activity areas, inside the climate-moderated confines of one of their self-constructed burrows, and specifically, at a depth in the burrow that minimizes exposure of eggs and embryos to lethal incubation temperatures. Nesting in “climate-controlled” burrows and nest guarding by females relaxes some of the constraints that drive nest site selection in other oviparous species.

  8. Nest site attributes and temporal patterns of northern flicker nest loss: effects of predation and competition.

    Science.gov (United States)

    Fisher, Ryan J; Wiebe, Karen L

    2006-04-01

    To date, most studies of nest site selection have failed to take into account more than one source of nest loss (or have combined all sources in one analysis) when examining nest site characteristics, leaving us with an incomplete understanding of the potential trade-offs that individuals may face when selecting a nest site. Our objectives were to determine whether northern flickers (Colaptes auratus) may experience a trade-off in nest site selection in response to mammalian nest predation and nest loss to a cavity nest competitor (European starling, Sturnus vulgaris). We also document within-season temporal patterns of these two sources of nest loss with the hypothesis that flickers may also be constrained in the timing of reproduction under both predatory and competitive influence. Mammalian predators frequently depredated flicker nests that were: lower to the ground, less concealed by vegetation around the cavity entrance and at the base of the nest tree, closer to coniferous forest edges and in forest clumps with a high percentage of conifer content. Proximity to coniferous edges or coniferous trees increased the probability of nest predation, but nests near conifers were less likely to be lost to starlings. Flickers may thus face a trade-off in nest site selection with respect to safety from predators or competitors. Models suggested that peaks of nest predation and nest loss to eviction occurred at the same time, although a competing model suggested that the peak of nest loss to starlings occurred 5 days earlier than the peak of mammalian predation. Differences in peaks of mammalian predation and loss to starlings may constrain any adjustment in clutch initiation date by flickers to avoid one source of nest loss.

  9. Nest marking behavior and chemical composition of olfactory cues involved in nest recognition in Megachile rotundata.

    Science.gov (United States)

    Guédot, Christelle; Buckner, James S; Hagen, Marcia M; Bosch, Jordi; Kemp, William P; Pitts-Singer, Theresa L

    2013-08-01

    In-nest observations of the solitary bee, Megachile rotundata (F.), revealed that nesting females apply olfactory cues to nests for nest recognition. On their way in and out of the nest, females drag the abdomen along the entire length of the nest, and sometimes deposit fluid droplets from the tip of the abdomen. The removal of bee-marked sections of the nest resulted in hesitation and searching behavior by females, indicating the loss of olfactory cues used for nest recognition. Chemical analysis of female cuticles and the deposits inside marked nesting tubes revealed the presence of hydrocarbons, wax esters, fatty aldehydes, and fatty alcohol acetate esters. Chemical compositions were similar across tube samples, but proportionally different from cuticular extracts. These findings reveal the importance of lipids as chemical signals for nest recognition and suggest that the nest-marking cues are derived from a source in addition to, or other than, the female cuticle.

  10. Wooden Calendar Sticks in Eastern Europe

    Science.gov (United States)

    Koleva, Vesselina; Koleva, Svetlana

    Wooden calendar sticks have preserved an archaic time-keeping tradition, which, during the Middle Ages, was one of the tools for establishing and disseminating Christian chronology and the liturgical calendars of the Western and Eastern Churches. The calendars vary in size and shape, type of signs, and structure of the record. Christian symbols interwoven with signs and pictograms mark days of importance in the ritual and economic year cycle. The wooden calendars are considered one of the proofs of the syncretism between the pagan tradition and Christian rites in folk cultures.

  11. Styrofoam-and-Velcro: An Alternative to Ball-and-Stick Models

    Directory of Open Access Journals (Sweden)

    Sawyer Rowan Masonjones

    2014-07-01

    Full Text Available For students learning biology at introductory levels, one of the most significant instructional barriers is their lack of preparation in chemistry. In upper-division college chemistry and biology courses, students employ ball-and-stick models in order to visualize molecular structures, but at the introductory biology level, models are inconsistently used and at the secondary level they are avoided altogether. Traditional ball-and-stick models perform poorly at all levels because they only show bonds, never valence electrons. This poses a problem for students who are visual or kinesthetic learners, as modeling electrons in the bonding process may be critical to understanding the mechanisms behind the biochemical reactions that serve as a foundation for biological concepts. Our molecular modeling kits show the action of valence electrons and correctly deal with the issue of polarity and partial charge, while still illustrating structure and function similarly to ball-and-stick models, allowing students to model nearly every reaction or molecule they may need to learn.  Additionally, this kit will foster model building exercises required as part of the Next Generation Science Standards (http://www.nextgenscience.org/next-generation-science-standards. This model was devloped in conjunction with 'Molecular Twister: A Game for Exploring Solution Chemistry' (JMBE Vol 15, No 1; http://jmbe.asm.org/index.php/jmbe/article/view/652 by the same authors, which uses principles derived from the present paper.

  12. On the formation of limit cycle of the friction-induced stick-slip vibration in oilwell drillstring

    Directory of Open Access Journals (Sweden)

    Xiaohua Zhu

    2015-03-01

    Full Text Available In this paper, the stick-slip vibration in oilwell drillstring is studied. The drilling system is modelled as a lumped-parameter torsional pendulum and the interaction between the drill bit and the rock is treated as Coulomb friction. Equation of motion of the drill bit is established and the dynamic responses of the drill bit are obtained. A drilling system with the drillstring length 3000 m is analysed, in which the system parameters are selected by reference to the actual drilling situation. After the slip vibrations in the initial stage, final state of the drill bit is a stable stick-slip vibration of which the limit cycle is a closed loop. In order to find the stability of the limit cycle corresponds to the periodically stick-slip vibration, different initial conditions for the drill bit are studied. Results show that the drill bit will lead to a periodic motion and the phase trajectories ultimately converge to the same limit cycle corresponds to stable stick-slip vibration.

  13. Impact of subject related factors and position of flight control stick on acquisition of simulated flying skills using a flight simulator

    Science.gov (United States)

    Cho, Bo-Keun

    Increasing demand on aviation industry calls for more pilots. Thus, pilot training systems and pilot-candidate screening systems are essential for civil and military flying training institutes. Before actual flight training, it is not easy to determine whether a flight trainee will be successful in the training. Due to the high cost of actual flight training, it would be better if there were low cost methods for screening and training candidates prior to the actual flight training. This study intended to determine if subject related factors and flight control stick position have an impact on acquisition of simulated flying skills using a PC-based flight simulator. The experimental model was a factorial design with repeated measures. Sixty-four subjects participated in the experiment and were divided into 8 groups. Experiment consisted of 8 sessions in which performance data, such as heading, altitude and airspeed were collected every 15 seconds. Collected data were analyzed using SAS statistical program. Result of multivariate analysis of variance indicated that the three independent variables: nationality, computer game experience, and flight stick position have significant impact on acquiring simulated flying skill. For nationality, Americans recorded higher scores in general (mean: 81.7) than Koreans (mean: 78.9). The difference in mean scores between Americans and Koreans was 2.8 percent. Regarding computer game experience, the difference between high experience group (82.3) and low experience group (78.3) is significant. For high experience group, American side-stick group recorded the highest (mean: 85.6), and Korean side-stick group (mean: 77.2) scored the lowest. For the low experience group, American center-stick group scored the highest (80.6), and the Korean side-stick group (74.2) scored the lowest points. Therefore, there is a significant difference between high experience group and low experience group. The results also reveal that the center-stick

  14. The Rise of Carrots and the Decline of Sticks

    NARCIS (Netherlands)

    de Geest, G.; Dari-Mattiacci, G.

    2013-01-01

    There is a remarkable tendency in modern legal systems to increasingly use carrots. This trend is not limited to legal systems but can also be observed in, for instance, parenting styles, social control mechanisms, and even law schools’ teaching methods. Yet, at first glance, sticks appear to be a

  15. Buteo Nesting Ecology: Evaluating Nesting of Swainson's Hawks in the Northern Great Plains.

    Science.gov (United States)

    Inselman, Will M; Datta, Shubham; Jenks, Jonathan A; Jensen, Kent C; Grovenburg, Troy W

    2015-01-01

    Swainson's hawks (Buteo swainsoni) are long-distance migratory raptors that nest primarily in isolated trees located in areas of high grassland density. In recent years, anthropogenic conversion of grassland habitat has raised concerns about the status of the breeding population in the northern Great Plains. In 2013, we initiated a study to investigate the influence of extrinsic factors influencing Swainson's hawk nesting ecology in north-central South Dakota and south-central North Dakota. Using ground and aerial surveys, we located and monitored nesting Swainson's hawk pairs: 73 in 2013 and 120 in 2014. We documented 98 successful breeding attempts that fledged 163 chicks; 1.52 and 1.72 fledglings per successful nest in 2013 and 2014, respectively. We used Program MARK to evaluate the influence of land cover on nest survival. The top model, SDist2Farm+%Hay, indicated that nest survival (fledging at least one chick) decreased as nests were located farther from farm sites and as the percent of hay cover increased within 1200-m of the nest site (34.4%; 95% CI = 27.6%-42.3%). We used logistic regression analysis to evaluate the influence of landscape variables on nest-site selection; Swainson's hawks selected for nest sites located closer to roads. We suggest that tree belts associated with farm sites, whether occupied or not, provide critical breeding sites for Swainson's hawks. Additionally, poor breeding success may be related to the late migratory behavior of this species which requires them to occupy marginal habitat due to other raptors occupying the most suitable habitat prior to Swainson's hawks arriving to the breeding grounds.

  16. Evidence for Ventilation through Collective Respiratory Movements in Giant Honeybee (Apis dorsata) Nests

    Science.gov (United States)

    Kastberger, Gerald; Waddoup, Dominique; Weihmann, Frank; Hoetzl, Thomas

    2016-01-01

    The Asian giant honeybees (Apis dorsata) build single-comb nests in the open, which makes this species particularly susceptible to environmental strains. Long-term infrared (IR) records documented cool nest regions (CNR) at the bee curtain (nCNR = 207, nnests > 20) distinguished by marked negative gradients (ΔTCNR/d 0) displaying the Venturi effect, which evidences funnel properties of CNRs. The air flows inwards through CNRs, which is verified by the negative spatial gradient ΔTCNR/d, by the positive grading of TCNR with Tamb and lastly by fanners which have directed their abdomens towards CNRs. Rare cases of RAT bee curtain (for ΔACNR/Δt > +0.4 cm2/s) displaying “inhalation” and “exhalation” cycling. “Inhalation” could be boosted by bees at the inner curtain layers, which stretch their extremities against the comb enlarging the inner nest lumen and thus causing a pressure fall which drives ambient air inwards through CNR funnels. The relaxing of the formerly “activated” bees could then trigger the “exhalation” process, which brings the bee curtain, passively by gravity, close to the comb again. That way, warm, CO2-enriched nest-borne air is pressed outwards through the leaking mesh of the bee curtain. This ventilation hypothesis is supported by IR imaging and laser vibrometry depicting CNRs in at least four aspects as low-resistance convection funnels for maintaining thermoregulation and restoring fresh air in the nest. PMID:27487188

  17. The hockey-stick method to estimate evening dim light melatonin onset (DLMO) in humans.

    Science.gov (United States)

    Danilenko, Konstantin V; Verevkin, Evgeniy G; Antyufeev, Viktor S; Wirz-Justice, Anna; Cajochen, Christian

    2014-04-01

    The onset of melatonin secretion in the evening is the most reliable and most widely used index of circadian timing in humans. Saliva (or plasma) is usually sampled every 0.5-1 hours under dim-light conditions in the evening 5-6 hours before usual bedtime to assess the dim-light melatonin onset (DLMO). For many years, attempts have been made to find a reliable objective determination of melatonin onset time either by fixed or dynamic threshold approaches. The here-developed hockey-stick algorithm, used as an interactive computer-based approach, fits the evening melatonin profile by a piecewise linear-parabolic function represented as a straight line switching to the branch of a parabola. The switch point is considered to reliably estimate melatonin rise time. We applied the hockey-stick method to 109 half-hourly melatonin profiles to assess the DLMOs and compared these estimates to visual ratings from three experts in the field. The DLMOs of 103 profiles were considered to be clearly quantifiable. The hockey-stick DLMO estimates were on average 4 minutes earlier than the experts' estimates, with a range of -27 to +13 minutes; in 47% of the cases the difference fell within ±5 minutes, in 98% within -20 to +13 minutes. The raters' and hockey-stick estimates showed poor accordance with DLMOs defined by threshold methods. Thus, the hockey-stick algorithm is a reliable objective method to estimate melatonin rise time, which does not depend on a threshold value and is free from errors arising from differences in subjective circadian phase estimates. The method is available as a computerized program that can be easily used in research settings and clinical practice either for salivary or plasma melatonin values.

  18. Implications of basal micro-earthquakes and tremor for ice stream mechanics: Stick-slip basal sliding and till erosion

    Science.gov (United States)

    Barcheck, C. Grace; Tulaczyk, Slawek; Schwartz, Susan Y.; Walter, Jacob I.; Winberry, J. Paul

    2018-03-01

    The Whillans Ice Plain (WIP) is unique among Antarctic ice streams because it moves by stick-slip. The conditions allowing stick-slip and its importance in controlling ice dynamics remain uncertain. Local basal seismicity previously observed during unstable slip is a clue to the mechanism of ice stream stick-slip and a window into current basal conditions, but the spatial extent and importance of this basal seismicity are unknown. We analyze data from a 2010-2011 ice-plain-wide seismic and GPS network to show that basal micro-seismicity correlates with large-scale patterns in ice stream slip behavior: Basal seismicity is common where the ice moves the least between unstable slip events, with small discrete basal micro-earthquakes happening within 10s of km of the central stick-slip nucleation area and emergent basal tremor occurring downstream of this area. Basal seismicity is largely absent in surrounding areas, where inter-slip creep rates are high. The large seismically active area suggests that a frictional sliding law that can accommodate stick-slip may be appropriate for ice stream beds on regional scales. Variability in seismic behavior over inter-station distances of 1-10 km indicates heterogeneity in local bed conditions and frictional complexity. WIP unstable slips may nucleate when stick-slip basal earthquake patches fail over a large area. We present a conceptual model in which basal seismicity results from slip-weakening frictional failure of over-consolidated till as it is eroded and mobilized into deforming till.

  19. [Correlation between physical characteristics of sticks and quality of traditional Chinese medicine pills prepared by plastic molded method].

    Science.gov (United States)

    Wang, Ling; Xian, Jiechen; Hong, Yanlong; Lin, Xiao; Feng, Yi

    2012-05-01

    To quantify the physical characteristics of sticks of traditional Chinese medicine (TCM) honeyed pills prepared by the plastic molded method and the correlation of adhesiveness and plasticity-related parameters of sticks and quality of pills, in order to find major parameters and the appropriate range impacting pill quality. Sticks were detected by texture analyzer for their physical characteristic parameters such as hardness and compression action, and pills were observed by visual evaluation for their quality. The correlation of both data was determined by the stepwise discriminant analysis. Stick physical characteristic parameter l(CD) can exactly depict the adhesiveness, with the discriminant equation of Y0 - Y1 = 6.415 - 41.594l(CD). When Y0 Y1, pills were adhesive with each other. Pills' physical characteristic parameters l(CD) and l(AC), Ar, Tr can exactly depict smoothness of pills, with the discriminant equation of Z0 - Z1 = -195.318 + 78.79l(AC) - 3 258. 982Ar + 3437.935Tr. When Z0 Z1, pills were rough on surface. The stepwise discriminant analysis is made to show the obvious correlation between key physical characteristic parameters l(CD) and l(AC), Ar, Tr of sticks and appearance quality of pills, defining the molding process for preparing pills by the plastic molded and qualifying ranges of key physical characteristic parameters characterizing intermediate sticks, in order to provide theoretical basis for prescription screening and technical parameter adjustment for pills.

  20. Sharp-Tailed Grouse Nest Survival and Nest Predator Habitat Use in North Dakota's Bakken Oil Field.

    Directory of Open Access Journals (Sweden)

    Paul C Burr

    Full Text Available Recent advancements in extraction technologies have resulted in rapid increases of gas and oil development across the United States and specifically in western North Dakota. This expansion of energy development has unknown influences on local wildlife populations and the ecological interactions within and among species. Our objectives for this study were to evaluate nest success and nest predator dynamics of sharp-tailed grouse (Tympanuchus phasianellus in two study sites that represented areas of high and low energy development intensities in North Dakota. During the summers of 2012 and 2013, we monitored 163 grouse nests using radio telemetry. Of these, 90 nests also were monitored using miniature cameras to accurately determine nest fates and identify nest predators. We simultaneously conducted predator surveys using camera scent stations and occupancy modeling to estimate nest predator occurrence at each site. American badgers (Taxidea taxus and striped skunks (Mephitis mephitis were the primary nest predators, accounting for 56.7% of all video recorded nest depredations. Nests in our high intensity gas and oil area were 1.95 times more likely to succeed compared to our minimal intensity area. Camera monitored nests were 2.03 times more likely to succeed than non-camera monitored nests. Occupancy of mammalian nest predators was 6.9 times more likely in our study area of minimal gas and oil intensity compared to the high intensity area. Although only a correlative study, our results suggest energy development may alter the predator community, thereby increasing nest success for sharp-tailed grouse in areas of intense development, while adjacent areas may have increased predator occurrence and reduced nest success. Our study illustrates the potential influences of energy development on the nest predator-prey dynamics of sharp-tailed grouse in western North Dakota and the complexity of evaluating such impacts on wildlife.

  1. Simple and easy assessment of falling risk in the elderly by functional reach test using elastic stick.

    Science.gov (United States)

    Demura, Shin-Ichi; Yamada, Takayoshi

    2007-10-01

    Dynamic balance ability related to maintaining postural stability during movement is closely tied to fall risk in the elderly. The functional reach (FR) test has been developed to evaluate their dynamic balance. Although a simple and new FR test using an elastic stick has been proposed by modifying the above original FR test, the abilities related to both FR tests are judged to differ because of the large difference in the testing method. This study aimed to compare center of gravity fluctuation, muscle activity and functional reach distance as measured by the original FR test and the elastic stick FR test. First, reach distance, back/forth and right/left moving distance of the center of gravity, and activity of the lower leg muscles (soleus and tibialis anterior) were compared between both tests based on data obtained from 30 young male adults. All parameters except for the right/left moving distance were significantly larger in the elastic stick FR test. Next, the reach distance was examined in both FR tests using 53 elderly subjects; it was significantly longer in the elastic stick FR test, but showed no significant sex difference. The reach distance in both tests was significantly shorter (about 7 cm) in the elderly than in young adults. In conclusion, the elastic stick FR test involves greater leg muscle strength exertion and forward transferring of the center of gravity as compared with the original FR test. Because the elastic stick FR test relates largely to leg muscle function and equilibrium function, it may be more useful for evaluating the dynamic balance ability of the elderly.

  2. Hawaii ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seabird nesting colonies in coastal Hawaii. Vector points in this data set represent locations of...

  3. Maryland ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for raptors in Maryland. Vector points in this data set represent bird nesting sites. Species-specific...

  4. Biomechanical testing of materials in avian nests provides insight into nest construction behaviour

    OpenAIRE

    Biddle, Lucia E.; Deeming, D. Charles; Goodman, Adrian M.

    2015-01-01

    Animals that use materials to build nest structures have long since fascinated biologists and engineers alike. Avian nests are generally composed of collected materials brought together into a cup-like structure in which the bird sits to incubate eggs and, in many cases, it is where chicks are reared. Hence, the materials in a nest can be presumed to be loaded in compression, but relatively few studies have investigated the mechanical role of the nest elements and their position w...

  5. Nesting biology of Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera, Crabronidae) in trap-nests in Southern Brazil

    OpenAIRE

    Buschini,M. L. T.; Niesing,F.; Wolff,L. L.

    2006-01-01

    This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in d...

  6. On a Desert Island with Unit Sticks, Continued Fractions and Lagrange

    Directory of Open Access Journals (Sweden)

    Victor J. Ricchezza

    2016-07-01

    Full Text Available GLY 4866, Computational Geology, provides an opportunity, welcomed by our faculty, to teach quantitative literacy to geology majors at USF. The course continues to evolve although the second author has been teaching it for some 20 years. This paper describes our experiences with a new lab activity that we are developing on the core issue of measurement and units. The activity is inspired by a passage in the 2008 publication of lectures that Joseph Louis Lagrange delivered at the Ecole Normale in 1795. The activity envisions that young scientists are faced with the need to determine the dimensions of a rectangle with no measuring device other than an unruled stick of unknown length – to hundredths of a stick length. Following Lagrange, the students use the stick to measure the lengths with continued fractions, and then they reduce the continued fractions and convert them to decimal form. In the process, these student veterans of calculus instruction learn that as a group they are not very good at the arithmetic of fractions, which they thought they learned in the fifth grade. The group score on a continued fraction item improved from 44% on the pre-course test to 84% on the post-course test in the first semester in which the new lab was included (Fall 2015.

  7. Louisiana ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seabird and wading bird nesting colonies in coastal Louisiana. Vector points in this data set represent...

  8. A Novel Tactile Sensor with Electromagnetic Induction and Its Application on Stick-Slip Interaction Detection

    Directory of Open Access Journals (Sweden)

    Yanjie Liu

    2016-03-01

    Full Text Available Real-time detection of contact states, such as stick-slip interaction between a robot and an object on its end effector, is crucial for the robot to grasp and manipulate the object steadily. This paper presents a novel tactile sensor based on electromagnetic induction and its application on stick-slip interaction. An equivalent cantilever-beam model of the tactile sensor was built and capable of constructing the relationship between the sensor output and the friction applied on the sensor. With the tactile sensor, a new method to detect stick-slip interaction on the contact surface between the object and the sensor is proposed based on the characteristics of friction change. Furthermore, a prototype was developed for a typical application, stable wafer transferring on a wafer transfer robot, by considering the spatial magnetic field distribution and the sensor size according to the requirements of wafer transfer. The experimental results validate the sensing mechanism of the tactile sensor and verify its feasibility of detecting stick-slip on the contact surface between the wafer and the sensor. The sensing mechanism also provides a new approach to detect the contact state on the soft-rigid surface in other robot-environment interaction systems.

  9. A Novel Tactile Sensor with Electromagnetic Induction and Its Application on Stick-Slip Interaction Detection

    Science.gov (United States)

    Liu, Yanjie; Han, Haijun; Liu, Tao; Yi, Jingang; Li, Qingguo; Inoue, Yoshio

    2016-01-01

    Real-time detection of contact states, such as stick-slip interaction between a robot and an object on its end effector, is crucial for the robot to grasp and manipulate the object steadily. This paper presents a novel tactile sensor based on electromagnetic induction and its application on stick-slip interaction. An equivalent cantilever-beam model of the tactile sensor was built and capable of constructing the relationship between the sensor output and the friction applied on the sensor. With the tactile sensor, a new method to detect stick-slip interaction on the contact surface between the object and the sensor is proposed based on the characteristics of friction change. Furthermore, a prototype was developed for a typical application, stable wafer transferring on a wafer transfer robot, by considering the spatial magnetic field distribution and the sensor size according to the requirements of wafer transfer. The experimental results validate the sensing mechanism of the tactile sensor and verify its feasibility of detecting stick-slip on the contact surface between the wafer and the sensor. The sensing mechanism also provides a new approach to detect the contact state on the soft-rigid surface in other robot-environment interaction systems. PMID:27023545

  10. Hepatitis B Vaccination Status and Needle stick Injuries among ...

    African Journals Online (AJOL)

    Background: Hepatits B virus (HBV) is the most common blood borne pathogen that poses an occupational risk to Health-care workers. The incidence of infection following needle stick injury has been reported to be high among medical students. Effective vaccines against HBV are available. The aim of this study was to ...

  11. In vivo incorporation of 1-14C-acetate into liver and plasma lipids of postnatally overfed rats

    International Nuclear Information System (INIS)

    Aust, L.; Noack, R.; Borchardt, M.; Akademie der Wissenschaften der DDR, Berlin-Buch. Forschungszentrum fuer Molekularbiologie und Medizin)

    1982-01-01

    Postnatal overnutrition due to breeding of rats in small nests (4 pups per dam) leads to distinct metabolic changes in later life stages even in conditions of ad libitum feeding. At an age of 5 months rats from small nests differ from those of large nests (14 pups per dam) in a significant higher level of liver triglycerides and cholesterol esters, whereas changes in plasma lipids concern only the increased cholesterol ester fraction. The relative distribution of in vivo incorporated 1- 14 C-acetate into liver lipids shows a higher moiety in the triglyceride fraction of animals from small nests but no changes of the relative distribution of activity among lipid fractions of plasma. These changes of lipid metabolism are discussed in relation to the development of an obese state of postnatally overfed animals. (author)

  12. Studying Hooke's Law by Using a Pogo Stick

    Science.gov (United States)

    Silva, Nicolas

    2011-01-01

    Perhaps the pogo stick was little Robert Hooke's favorite childhood toy, consisting of a stiff spring inserted in a tube fixed at the upper end and connected to a moveable rod at the other. Hand grips and a foot rest are connected to the tube. The idea is to jump on it taking advantage of the force provided by the spring when it is compressed.…

  13. Nest-site selection and nest success of an Arctic-breeding passerine, Smith's Longspur, in a changing climate

    Science.gov (United States)

    McFarland, Heather R.; Kendall, Steve J.; Powell, Abby

    2017-01-01

    Despite changes in shrub cover and weather patterns associated with climate change in the Arctic, little is known about the breeding requirements of most passerines tied to northern regions. We investigated the nesting biology and nest habitat characteristics of Smith's Longspurs (Calcarius pictus) in 2 study areas in the Brooks Range of Alaska, USA. First, we examined variation in nesting phenology in relation to local temperatures. We then characterized nesting habitat and analyzed nest-site selection for a subset of nests (n = 86) in comparison with paired random points. Finally, we estimated the daily survival rate of 257 nests found in 2007–2013 with respect to both habitat characteristics and weather variables. Nest initiation was delayed in years with snow events, heavy rain, and freezing temperatures early in the breeding season. Nests were typically found in open, low-shrub tundra, and never among tall shrubs (mean shrub height at nests = 26.8 ± 6.7 cm). We observed weak nest-site selection patterns. Considering the similarity between nest sites and paired random points, coupled with the unique social mating system of Smith's Longspurs, we suggest that habitat selection may occur at the neighborhood scale and not at the nest-site scale. The best approximating model explaining nest survival suggested a positive relationship with the numbers of days above 21°C that an individual nest experienced; there was little support for models containing habitat variables. The daily nest survival rate was high (0.972–0.982) compared with that of most passerines in forested or grassland habitats, but similar to that of passerines nesting on tundra. Considering their high nesting success and ability to delay nest initiation during inclement weather, Smith's Longspurs may be resilient to predicted changes in weather regimes on the breeding grounds. Thus, the greatest threat to breeding Smith's Longspurs associated with climate change may be the loss of low

  14. Nesting Activity of Loggerhead Turtles (Caretta caretta at Göksu Delta, Turkey during 2004 and 2008 nesting seasons

    Directory of Open Access Journals (Sweden)

    Salih H. Durmus

    2011-07-01

    Full Text Available Göksu Delta is one of the most important nesting beaches in Turkey for the endangered loggerhead turtle (Caretta caretta. This paper provides information on the nesting activities of loggerhead turtles, the spatial and temporal distribution of nesting, nesting success, nesting density, hatching success, incubation duration and clutch size over two nesting seasons. A total of 902 emergences occurred over two seasons, of which 239 (26.5% nests were deposited (137 nests in 2004 and 102 nests in 2008 and the overall mean nesting density was 3.4 nests/km. The peak of nesting emergences takes place mainly in June. Of the overall nests, 226 (94.6% were excavated and 16044 eggs were counted. Of these eggs, 3680 (22.9% hatchlings emerged and 2695 (73.2% of hatchlings of them were able to reach the sea. The mean number of eggs per clutch was 71 (range: 15 – 143. The shortest and longest incubation duration in these 2 seasons ranged from 46 to 62 days with a mean of 53 days. The main problems are negatively affecting loggerhead turtle population at Göksu Delta are dense jackal predation both adult and eggs and inundation in nests. The average nesting effort here (mean: 119.5 nests/season confirms that Göksu Delta is one of the most important nesting sites for loggerhead turtles in Turkey.

  15. TALKING STICK SEBAGAI INOVASI DALAM AKTIVITAS MENGOMUNIKASIKAN UNTUK MENINGKATKAN PEMAHAMAN SISWA

    Directory of Open Access Journals (Sweden)

    Anak Agung Gede Agung

    2017-10-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui pengaruh aktivitas mengomunikasikan dalam pendekatan saintifik berbantuan talking stick terhadap dimensi proses kognitif siswa kelas IV tahun pelajaran 2016/2017 di Sd Kabupaten Buleleng.  Penelitian ini merupakan penelitian eksperimen semu dengan populasi seluruh kelompok siswa kelas IV di SD rintisan kurikulum  2013 di Kabupaten buleleng. Sampel penelitian sebanyak dua kelas yang berjumlah 76 siswa. Data dikumpulkan dengan teknik tes serta dianalisis dengan teknik statistik deskriptif dan  inferensial (uji t. Hasil penelitian ini menunjukkan bahwa terdapat perbedaan dimensi proses kognitif yang signifikan antara siswa yang dibelajarkan dengan aktivitas mengomunikasikan dalam pendekatan saintifik berbantuan talking stick dan siswa yang dibelajarkan dengan aktivitas pembelajaran konvensional (thitung = 5,27 > ttabel = 1,99, serta kategori pemahaman dalam dimensi proses kognitif lebih tinggi dari pada kategori lainnya.

  16. Modelling the tuned criticality in stick-slip friction during metal cutting

    International Nuclear Information System (INIS)

    Wang, Q; Ye, G G; Dai, L H; Lu, C

    2015-01-01

    Cutting is a ubiquitous process in nature and man-made systems. Here we demonstrate that, based on morphological patterns observed in experiments, the friction behaviour of metal cutting exhibits a criticality with cutting speed as a tuned parameter. The corresponding stick-slip events can be described by a power law distribution. A dynamic thermo-mechanical model is developed to investigate how such a tuned criticality occurs. It is shown that, in terms of the linear stability analysis, stick-slip friction is due to the thermo-mechanical instability and dynamical interaction between shear dissipation and nonlinear friction. Moreover, there is a secondary transition from a criticality state to a limit cycle that is dominated by the inertia effect, which is similar to the frequency lock phenomenon in a forced Duffing oscillator. (paper)

  17. "Fist, Stick, Knife, Gun": Getting Real in Upward Bound.

    Science.gov (United States)

    Pace, Barbara G.; Adkins, Theresa A.

    2002-01-01

    Describes how a teacher found literature for Upward Bound students. Presents Geoffrey Canada's "Fist, Stick, Knife, Gun: A Personal History of Violence in America" as a nonfiction work to provide clarity and connections that might not have been available in a fictional work, yet it had elements of literary fiction that made the text…

  18. Buteo Nesting Ecology: Evaluating Nesting of Swainson’s Hawks in the Northern Great Plains

    Science.gov (United States)

    Inselman, Will M.; Datta, Shubham; Jenks, Jonathan A.; Jensen, Kent C.; Grovenburg, Troy W.

    2015-01-01

    Swainson’s hawks (Buteo swainsoni) are long-distance migratory raptors that nest primarily in isolated trees located in areas of high grassland density. In recent years, anthropogenic conversion of grassland habitat has raised concerns about the status of the breeding population in the northern Great Plains. In 2013, we initiated a study to investigate the influence of extrinsic factors influencing Swainson’s hawk nesting ecology in north-central South Dakota and south-central North Dakota. Using ground and aerial surveys, we located and monitored nesting Swainson’s hawk pairs: 73 in 2013 and 120 in 2014. We documented 98 successful breeding attempts that fledged 163 chicks; 1.52 and 1.72 fledglings per successful nest in 2013 and 2014, respectively. We used Program MARK to evaluate the influence of land cover on nest survival. The top model, S Dist2Farm+%Hay, indicated that nest survival (fledging at least one chick) decreased as nests were located farther from farm sites and as the percent of hay cover increased within 1200-m of the nest site (34.4%; 95% CI = 27.6%–42.3%). We used logistic regression analysis to evaluate the influence of landscape variables on nest-site selection; Swainson’s hawks selected for nest sites located closer to roads. We suggest that tree belts associated with farm sites, whether occupied or not, provide critical breeding sites for Swainson’s hawks. Additionally, poor breeding success may be related to the late migratory behavior of this species which requires them to occupy marginal habitat due to other raptors occupying the most suitable habitat prior to Swainson’s hawks arriving to the breeding grounds. PMID:26327440

  19. Relating stick-slip friction experiments to earthquake source parameters

    Science.gov (United States)

    McGarr, Arthur F.

    2012-01-01

    Analytical results for parameters, such as static stress drop, for stick-slip friction experiments, with arbitrary input parameters, can be determined by solving an energy-balance equation. These results can then be related to a given earthquake based on its seismic moment and the maximum slip within its rupture zone, assuming that the rupture process entails the same physics as stick-slip friction. This analysis yields overshoots and ratios of apparent stress to static stress drop of about 0.25. The inferred earthquake source parameters static stress drop, apparent stress, slip rate, and radiated energy are robust inasmuch as they are largely independent of the experimental parameters used in their estimation. Instead, these earthquake parameters depend on C, the ratio of maximum slip to the cube root of the seismic moment. C is controlled by the normal stress applied to the rupture plane and the difference between the static and dynamic coefficients of friction. Estimating yield stress and seismic efficiency using the same procedure is only possible when the actual static and dynamic coefficients of friction are known within the earthquake rupture zone.

  20. Non-desired transitions and sliding-mode control of a multi-DOF mechanical system with stick-slip oscillations

    International Nuclear Information System (INIS)

    Navarro-Lopez, Eva M.; Liceaga-Castro, Eduardo

    2009-01-01

    Systems with discontinuous elements exhibit a wide variety of complex phenomena which must be considered in the control design process. A dynamical sliding-mode control is used to avoid different bit sticking problems appearing in conventional vertical oilwell drillstrings. The aim of the control system is to drive the rotary velocities of drillstring components to specified values. A discontinuous lumped-parameter torsional model of four degrees of freedom is considered. This model is more generic than those so far reported in the literature. The closed-loop system dynamics have four discontinuity surfaces. One of these surfaces is introduced in order to accomplish the control goal despite variations of key drilling parameters, such as, the weight on the bit, the top-rotary velocity and friction characteristics. Self-excited bit stick-slip oscillations and sticking phenomena are avoided with the controller here proposed. Moreover, an alternative procedure to investigate the stick-slip motion is presented, it is based on the study of the stability characteristics of the different system equilibria and their relationships to different sliding motions.

  1. Stick-slip friction of gecko-mimetic flaps on smooth and rough surfaces.

    Science.gov (United States)

    Das, Saurabh; Cadirov, Nicholas; Chary, Sathya; Kaufman, Yair; Hogan, Jack; Turner, Kimberly L; Israelachvili, Jacob N

    2015-03-06

    The discovery and understanding of gecko 'frictional-adhesion' adhering and climbing mechanism has allowed researchers to mimic and create gecko-inspired adhesives. A few experimental and theoretical approaches have been taken to understand the effect of surface roughness on synthetic adhesive performance, and the implications of stick-slip friction during shearing. This work extends previous studies by using a modified surface forces apparatus to quantitatively measure and model frictional forces between arrays of polydimethylsiloxane gecko footpad-mimetic tilted microflaps against smooth and rough glass surfaces. Constant attachments and detachments occur between the surfaces during shearing, as described by an avalanche model. These detachments ultimately result in failure of the adhesion interface and have been characterized in this study. Stick-slip friction disappears with increasing velocity when the flaps are sheared against a smooth silica surface; however, stick-slip was always present at all velocities and loads tested when shearing the flaps against rough glass surfaces. These results demonstrate the significance of pre-load, shearing velocity, shearing distances, commensurability and shearing direction of gecko-mimetic adhesives and provide us a simple model for analysing and/or designing such systems. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  2. Accurate alpha sticking fractions from improved calculations relevant for muon catalyzed fusion

    International Nuclear Information System (INIS)

    Szalewicz, K.

    1990-05-01

    Recent experiments have shown that under proper conditions a single muon may catalyze almost two hundred fusions in its lifetime. This process proceeds through formation of muonic molecular ions. Properties of these ions are central to the understanding of the phenomenon. Our work included the most accurate calculations of the energy levels and Coulombic sticking fractions for tdμ and other muonic molecular ions, calculations of Auger transition rates, calculations of corrections to the energy levels due to interactions with the most molecule, and calculation of the reactivation of muons from α particles. The majority of our effort has been devoted to the theory and computation of the influence of the strong nuclear forces on fusion rates and sticking fractions. We have calculated fusion rates for tdμ including the effects of nuclear forces on the molecular wave functions. We have also shown that these results can be reproduced to almost four digit accuracy by using a very simple quasifactorizable expression which does not require modifications of the molecular wave functions. Our sticking fractions are more accurate than any other theoretical values. We have used a more sophisticated theory than any other work and our numerical calculations have converged to at least three significant digits

  3. Unusual raptor nests around the world

    Science.gov (United States)

    Ellis, D.H.; Craig, T.; Craig, E.; Postupalsky, S.; LaRue, C.T.; Nelson, R.W.; Anderson, D.W.; Henny, C.J.; Watson, J.; Millsap, B.A.; Dawson, J.W.; Cole, K.L.; Martin, E.M.; Margalida, A.; Kung, P.

    2009-01-01

    From surveys in many countries, we report raptors using unusual nesting materials (e.g., paper money, rags, metal, antlers, and large bones) and unusual nesting situations. For example, we documented nests of Steppe Eagles Aquila nipalensis and Upland Buzzards Buteo hemilasius on the ground beside well-traveled roads, Saker Falcon Falco cherrug eyries in attics and a cistern, and Osprey Pandion haliaetus nests on the masts of boats and on a suspended automobile. Other records include a Golden Eagle A. chrysaetos nest 7.0 m in height, believed to be the tallest nest ever described, and, for the same species, we report nesting in rudimentary nests. Some nest sites are within a few meters of known predators or competitors. These unusual observations may be important in revealing the plasticity of a species' behavioral repertoire. ?? 2009 The Raptor Research Foundation, Inc.

  4. Spectral analysis of the stick-slip phenomenon in "oral" tribological texture evaluation.

    Science.gov (United States)

    Sanahuja, Solange; Upadhyay, Rutuja; Briesen, Heiko; Chen, Jianshe

    2017-08-01

    "Oral" tribology has become a new paradigm in food texture studies to understand complex texture attributes, such as creaminess, oiliness, and astringency, which could not be successfully characterized by traditional texture analysis nor by rheology. Stick-slip effects resulting from intermittent sliding motion during kinetic friction of oral mucosa could constitute an additional determining factor of sensory perception where traditional friction coefficient values and their Stribeck regimes fail in predicting different lubricant (food bolus and saliva) behaviors. It was hypothesized that the observed jagged behavior of most sliding force curves are due to stick-slip effects and depend on test velocity, normal load, surface roughness as well as lubricant type. Therefore, different measurement set-ups were investigated: sliding velocities from 0.01 to 40 mm/s, loads of 0.5 and 2.5 N as well as a smooth and a textured silicone contact surface. Moreover, dry contact measurements were compared to model food systems, such as water, oil, and oil-in-water emulsions. Spectral analysis permitted to extract the distribution of stick-slip magnitudes for specific wave numbers, characterizing the occurrence of jagged force peaks per unit sliding distance, similar to frequencies per unit time. The spectral features were affected by all the above mentioned tested factors. Stick-slip created vibration frequencies in the range of those detected by oral mechanoreceptors (0.3-400 Hz). The study thus provides a new insight into the use of tribology in food psychophysics. Dynamic spectral analysis has been applied for the first time to the force-displacement curves in "oral" tribology. Analyzing the stick-slip phenomenon in the dynamic friction provides new information that is generally overlooked or confused with machine noise and which may help to understand friction-related sensory attributes. This approach allows us to differentiate samples that have similar friction coefficient

  5. Antioxidant capacity of chewing stick miswak Salvadora persica

    OpenAIRE

    Mohamed, Saleh A; Khan, Jalaluddin A

    2013-01-01

    Background Chewing stick (miswak Salvadora persica L.) is an effective tool for oral hygiene. It possessed various biological properties including significant antibacterial and anti-fungal effects. In the present study, we evaluated the antioxidant compounds in miswak. Method Miswak root was extracted with 80% methanol. Methanol extract as antioxidant was evaluated by using DPPH, ABTS and phosphomolybdenum complex assays and analysis by GC-MS. Peroxidase, catalase and polyphenoloxidase assays...

  6. Sexually selected nest-building--Pomatoschistus minutus males build smaller nest-openings in the presence of sneaker males.

    Science.gov (United States)

    Svensson, O; Kvarnemo, C

    2003-09-01

    Both natural selection and sexual selection may act on nest-building. We tested experimentally how different regimes of egg-predation and male-male competition influence nest-building before mating, using the marine fish sand goby, Pomatoschistus minutus. Males with sneaker males present built the smallest nest-openings, smaller than males held alone or with Pomatoschistus microps males (which may predate eggs and compete over nest-sites but not compete over fertilizations). Males with visual access to other nest-building males tended also to build smaller openings than males held alone or with P. microps. Males with egg-predators present built nests with openings not differing significantly from any other treatment. Our results indicate that the small nest-openings found in the sneaker male treatment are sexually selected through protection against sneaking or by female choice. Across treatments, time span before a male started to build his nest also explained variation in nest-opening width; males starting late built larger nest-openings.

  7. The sticking probability for H-2 on some transition metals at a hydrogen pressure of 1 bar

    DEFF Research Database (Denmark)

    Johansson, Martin; Lytken, Ole; Chorkendorff, Ib

    2008-01-01

    The sticking probability for hydrogen on films of Co, Ni, Cu, Ru, Rh, Pd, Ir, and Pt supported on graphite has been measured at a hydrogen pressure of 1 bar in the temperature range 40–200 °C. The sticking probability is found to increase in the order Ni, Co, Ir, Pd, Pt, Rh, and Ru at temperature...

  8. Development with age of nest box use and gregarious nesting in laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch

    2010-01-01

    in position (left + corner, middle, and right). Nesting behaviour was video recorded for 5 days in each of five distinct periods: age 20, 26, 32, 38, and 44 weeks. The total number of visits and the number of gregarious visits were higher in the left nest box than in the other two nest boxes at all ages...

  9. Predation on simulated duck nests in relation to nest density and landscape structure

    Czech Academy of Sciences Publication Activity Database

    Padyšáková, E.; Šálek, Martin; Poledník, L.; Sedláček, František; Albrecht, Tomáš

    2010-01-01

    Roč. 37, č. 7 (2010), s. 597-603 ISSN 1035-3712 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60870520; CEZ:AV0Z60930519 Keywords : density-dependent predation * littoral patch * landscape type * nest predators * nest success * simulated nests Subject RIV: EG - Zoology Impact factor: 1.205, year: 2010

  10. The sticking probability for H-2 in presence of CO on some transition metals at a hydrogen pressure of 1 bar

    DEFF Research Database (Denmark)

    Johansson, Martin; Lytken, Ole; Chorkendorff, Ib

    2008-01-01

    The sticking probability for H-2 on Ni, Co, Cu, Rh, Ru, Pd, it and Pt metal films supported on graphite has been investigated in a gas mixture consisting of 10 ppm carbon monoxide in hydrogen at a total pressure of 1 bar in the temperature range 40-200 degrees C. Carbon monoxide inhibits the stic......The sticking probability for H-2 on Ni, Co, Cu, Rh, Ru, Pd, it and Pt metal films supported on graphite has been investigated in a gas mixture consisting of 10 ppm carbon monoxide in hydrogen at a total pressure of 1 bar in the temperature range 40-200 degrees C. Carbon monoxide inhibits...... the sticking probability significantly for all the metals, even at 200 degrees C. In the presence of 10 ppm CO, the sticking probability increases in the order It, Pt, Ni, Co, Pd, Rh, Ru, whereas for Cu, it is below the detection limit of the measurement, even in pure H2. The sticking probability for H2...

  11. Discovery of a new Kittlitz's murrelet nest: Clues to habitat selection and nest-site fidelity

    Science.gov (United States)

    Piatt, John F.; Naslund, Nancy L.; van Pelt, Thomas I.

    1999-01-01

    On 13 June 1993, a new Kittlitz's murrelet (Brachyramphus brevirostris) nest was discovered near Red Mountain on the Kenai Peninsula, Alaska. The nest was on a 22° slope at about 900 m elevation with a northeast aspect, and contained a 60.2 × 40.6 mm egg that weighed 49.0 g. Downy feathers and weathered fecal material found at the nest indicated re-use from a previous year, suggesting possible nest site fidelity. The nest was located in an area scoured by winds and free of snow during early spring, suggesting that this may be an important mesoscale factor influencing selection of nesting habitat. Proximity to suitable foraging habitat, particularly sheltered bays and glacial river outflows, may affect breeding habitat choice over larger spatial scales.

  12. Nest-site selection by cavity-nesting birds in relation to postfire salvage logging

    Science.gov (United States)

    Victoria A. Saab; Robin E. Russell; Jonathan G. Dudley

    2009-01-01

    Large wildfire events in coniferous forests of the western United States are often followed by postfire timber harvest. The long-term impacts of postfire timber harvest on fire-associated cavity-nesting bird species are not well documented. We studied nest-site selection by cavity-nesting birds over a 10-year period (1994-2003), representing 1-11 years after fire, on...

  13. Artificial covering on trap nests improves the colonization of trap-nesting wasps

    OpenAIRE

    Taki, Hisatomo; Kevan, Peter G.; Viana, Blandina Felipe; Silva, Fabiana O.; Buck, Matthias

    2008-01-01

    Acesso restrito: Texto completo. p. 225-229 To evaluate the role that a trap-nest cover might have on sampling methodologies, the abundance of each species of trap-nesting Hymenoptera and the parasitism rate in a Canadian forest were compared between artificially covered and uncovered traps. Of trap tubes exposed at eight forest sites in six trap-nest boxes, 531 trap tubes were occupied and 1216 individuals of 12 wasp species of four predatory families, Vespidae (Eumeninae), Crabronidae...

  14. Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird

    OpenAIRE

    Hollander, Franck A.; Van Dyck, Hans; San Martin, Gilles; Titeux, Nicolas

    2015-01-01

    In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius ...

  15. Detonation Propagation in Slabs and Axisymmetric Rate Sticks

    Science.gov (United States)

    Romick, Christopher; Aslam, Tariq

    Insensitive high explosives (IHE) have many benefits; however, these IHEs exhibit longer reaction zones than more conventional high explosives (HE). This makes IHEs less ideal explosives and more susceptible to edge effects as well as other performance degradation issues. Thus, there is a resulting reduction in the detonation speed within the explosive. Many HE computational models, e. g. WSD, SURF, CREST, have shock-dependent reaction rates. This dependency places a high value on having an accurate shock speed. In the common practice of shock-capturing, there is ambiguity in the shock-state due to smoothing of the shock-front. Moreover, obtaining an accurate shock speed with shock-capturing becomes prohibitively computationally expensive in multiple dimensions. The use of shock-fitting removes the ambiguity of the shock-state as it is one of the boundaries. As such, the required resolution for a given error in the detonation speed is less than with shock-capturing. This allows for further insight into performance degradation. A two-dimensional shock-fitting scheme has been developed for unconfined slabs and rate sticks of HE. The HE modeling is accomplished by Euler equations utilizing several models with single-step irreversible kinetics in slab and rate stick geometries. Department of Energy - LANL.

  16. SMART STICK DESIGN WITH OBSTACLE DETECTION AND NAVIGATION AS THE HELPING TOOL FOR BLIND PEOPLE

    OpenAIRE

    Sumar Hadi*, Susilo Adi Widyanto, Paryanto, Kurnia Chamid, Rachmat Muhamad Andika

    2018-01-01

    Smart stick designed for the blind people, this appliance can help detect obstacles with the use of infrared sensor, ultrasonic and water. The obstacles in a distance of about 3 m can be detected assistance from this sensor. In addition, we use GPS (Global Positioning System) to give the position and navigation on the stick. Using GPS (Global Positioning System) help the blind people reaches its destination. GPS (Global Positioning System) recipients to get the location of the latest and the ...

  17. Influence of movement regime of stick-slip process on the size distribution of accompanying acoustic emission characteristics

    Science.gov (United States)

    Matcharashvili, Teimuraz; Chelidze, Tamaz; Zhukova, Natalia; Mepharidze, Ekaterine; Sborshchikov, Alexander

    2010-05-01

    Many scientific works on dynamics of earthquake generation are devoted to qualitative and quantitative reproduction of behavior of seismic faults. Number of theoretical, numerical or physical models are already designed for this purpose. Main assumption of these works is that the correct model must be capable to reproduce power law type relation for event sizes with magnitudes greater than or equal to a some threshold value, similar to Gutenberg-Richter (GR) law for the size distribution of earthquakes. To model behavior of a seismic faults in laboratory conditions spring-block experimental systems are often used. They enable to generate stick-slip movement, intermittent behavior occurring when two solids in contact slide relative to each other driven at a constant velocity. Wide interest to such spring-block models is caused by the fact that stick-slip is recognized as a basic process underlying earthquakes generation along pre-existing faults. It is worth to mention, that in stick slip experiments reproduction of power law, in slip events size distribution, with b values close or equal to the one found for natural seismicity is possible. Stick-slip process observed in these experimental models is accompanied by a transient elastic waves propagation generated during the rapid release of stress energy in spring-block system. Oscillations of stress energy can be detected as a characteristic acoustic emission (AE). Accompanying stick slip AE is the subject of intense investigation, but many aspects of this process are still unclear. In the present research we aimed to investigate dynamics of stick slip AE in order to find whether its distributional properties obey power law. Experiments have been carried out on spring-block system consisting of fixed and sliding plates of roughly finished basalt samples. The sliding block was driven with a constant velocity. Experiments have been carried out for five different stiffness of pulling spring. Thus five different regimes

  18. Interaction in Balanced Cross Nested Designs

    Science.gov (United States)

    Ramos, Paulo; Mexia, João T.; Carvalho, Francisco; Covas, Ricardo

    2011-09-01

    Commutative Jordan Algebras, CJA, are used in the study of mixed models obtained, through crossing and nesting, from simpler ones. In the study of cross nested models the interaction between nested factors have been systematically discarded. However this can constitutes an artificial simplification of the models. We point out that, when two crossed factors interact, such interaction is symmetric, both factors playing in it equivalent roles, while when two nested factors interact, the interaction is determined by the nesting factor. These interactions will be called interactions with nesting. In this work we present a coherent formulation of the algebraic structure of models enabling the choice of families of interactions between cross and nested factors using binary operations on CJA.

  19. Nonparametric Bayesian models through probit stick-breaking processes.

    Science.gov (United States)

    Rodríguez, Abel; Dunson, David B

    2011-03-01

    We describe a novel class of Bayesian nonparametric priors based on stick-breaking constructions where the weights of the process are constructed as probit transformations of normal random variables. We show that these priors are extremely flexible, allowing us to generate a great variety of models while preserving computational simplicity. Particular emphasis is placed on the construction of rich temporal and spatial processes, which are applied to two problems in finance and ecology.

  20. Parental investment decisions in response to ambient nest-predation risk versus actual predation on the prior nest

    Science.gov (United States)

    Chalfoun, A.D.; Martin, T.E.

    2010-01-01

    Theory predicts that parents should invest less in dependent offspring with lower reproductive value, such as those with a high risk of predation. Moreover, high predation risk can favor reduced parental activity when such activity attracts nest predators. Yet, the ability of parents to assess ambient nest-predation risk and respond adaptively remains unclear, especially where nest-predator assemblages are diverse and potentially difficult to assess. We tested whether variation in parental investment by a multi-brooded songbird (Brewer's Sparrow, Spizella breweri) in an environment (sagebrush steppe) with diverse predators was predicted by ambient nest-predation risk or direct experience with nest predation. Variation among eight sites in ambient nest-predation risk, assayed by daily probabilities of nest predation, was largely uncorrelated across four years. In this system risk may therefore be unpredictable, and aspects of parental investment (clutch size, egg mass, incubation rhythms, nestling-feeding rates) were not related to ambient risk. Moreover, investment at first nests that were successful did not differ from that at nests that were depredated, suggesting parents could not assess and respond to territorylevel nest-predation risk. However, parents whose nests were depredated reduced clutch sizes and activity at nests attempted later in the season by increasing the length of incubation shifts (on-bouts) and recesses (off-bouts) and decreasing trips to feed nestlings. In this unpredictable environment parent birds may therefore lack sufficient cues of ambient risk on which to base their investment decisions and instead rely on direct experience with nest predation to inform at least some of their decisions. ?? 2010 The Cooper Ornithological Society.

  1. Neither a Toddler nor a Stick-in-the-Mud

    Science.gov (United States)

    Smith, Andrea Livi

    2011-01-01

    The goal of this paper is to express the views from the "outside," from laypeople who want to go to museums, but perhaps find themselves not going very often. Adult visitors to history museums are often treated as either toddlers or sticks-in-the-mud, where they are assumed to break anything they touch, or enjoy didactic lectures. As a result,…

  2. Landscape forest cover and edge effects on songbird nest predation vary by nest predator

    Science.gov (United States)

    W. Andrew Cox; Frank R. III Thompson; John. Faaborg

    2012-01-01

    Rates of nest predation for birds vary between and within species across multiple spatial scales, but we have a poor understanding of which predators drive such patterns. We video-monitored nests and identified predators at 120 nests of the Acadian Flycatcher (Empidonax virescens) and the Indigo Bunting (Passerina cyanea) at eight...

  3. Nest Material Shapes Eggs Bacterial Environment.

    Directory of Open Access Journals (Sweden)

    Cristina Ruiz-Castellano

    Full Text Available Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus of eggshells in nests of spotless starlings (Sturnus unicolor at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and

  4. Nest Material Shapes Eggs Bacterial Environment.

    Science.gov (United States)

    Ruiz-Castellano, Cristina; Tomás, Gustavo; Ruiz-Rodríguez, Magdalena; Martín-Gálvez, David; Soler, Juan José

    2016-01-01

    Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus) of eggshells in nests of spotless starlings (Sturnus unicolor) at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and geographically

  5. Design of nest access grids and perches in front of the nests: Influence on the behavior of laying hens.

    Science.gov (United States)

    Stämpfli, K; Buchwalder, T; Fröhlich, E K F; Roth, B A

    2013-04-01

    In aviary systems for laying hens, it is important to provide suitable nest access platforms in front of the nests, allowing hens to reach and explore each of the nests easily. This access platform is needed to achieve good nest acceptance by the hens and thereby prevent mislaid eggs. In the present experiment, the behavior of hens using 2 different nest access platforms, a plastic grid and 2 wooden perches, was examined. Furthermore, the nests were placed on both sides of the aviary rack (corridor side and outdoor side), either integrated into the aviary rack itself (integrated nest; IN) or placed on the walls of the pens (wall nest; WN), resulting in a 2 × 2 factorial design Four thousand five hundred white laying hens were housed in 20 test pens. The eggs in the nests and mislaid eggs were collected daily, and the behavior of hens on the nest accesses was filmed during wk 25 and 26, using focal observation and scan sampling methods. More balancing, body contact, and agonistic interactions were expected for nests with perches, whereas more walking and nest inspections were expected for nests with grids. There were more mislaid eggs and balancing found in pens equipped with nests with wooden perches. More agonistic interactions and balancing, less standing, and a longer duration of nest inspection were found with the WN compared with the IN. Interactions between platform design and position of the nests were found for duration of nest visits, body contact, and walking, with the highest amount for WN equipped with plastic grids. Nests on the corridor side were favored by the hens. Nest-related behaviors, such as nest inspection, standing, and walking, decreased over time as did the number of hens on the nest accesses, whereas sitting increased. These results indicate that the hens had more difficulties in gripping the perches as designed. The lower number of hens on the nest access platforms in front of IN may be due to a better distribution around nests and tier

  6. Small-scale area effect on species richness and nesting occupancy of cavity-nesting bees and wasps

    Directory of Open Access Journals (Sweden)

    Rafael D. Loyola

    2011-03-01

    Full Text Available Small-scale area effect on species richness and nesting occupancy of cavity-nesting bees and wasps. The research was conducted in an urban forest remnant in southeast Brazil. We tested the predictions of the following hypotheses: (1 larger areas present higher species richness of bees and wasps, (2 solitary bees and wasps occupy more nests in larger areas, (3 rare species occupy more nests in smaller areas. We sampled Aculeate bees and wasps using trap nests from February to November 2004. We placed trap nests in sampling units (SU with different size (25, 100 and 400 m² located in 6 ha of secondary mesophytic forest. One hundred and thirty-seven trap nests were occupied by seven species of bees and four species of wasps. We found an increase in wasp, but not bee species richness following increase in SU size. Hymenoptera richness (i.e. bees plus wasps was also greater in larger SU. Both the number and density of occupied nests increased with SU size. The wasp Trypoxylon lactitarse responded significantly to area size, larger SU having more occupied nests. The same pattern was exhibited by the wasp Auplopus militaris, the Megachile bee species, and the bee Anthodioctes megachiloides. Only Trypoxylon sp. was not affected by SU size. Our results show that cavity-nesting bee and wasps respond differently to the area effects. Such findings must be complemented by information on the frequency and dynamics of area colonization and nest occupancy by species of solitary Hymenoptera.

  7. Bee species-specific nesting material attracts a generalist parasitoid: implications for co-occurring bees in nest box enhancements.

    Science.gov (United States)

    Macivor, J Scott; Salehi, Baharak

    2014-08-01

    Artificial nests (e.g., nest boxes) for bees are increasingly being used to contribute to nesting habitat enhancement for bees that use preexisting cavities to provision brood. They usually incorporate additional nesting materials that vary by species. Cavity-nesting bees are susceptible to brood parasitoids that recognize their host(s) using visual and chemical cues. Understanding the range of cues that attract parasitoids to bee nests, including human-made analogues, is important if we wish to control parasitism and increase the potential value of artificial nests as habitat-enhancement strategies. In this study, we investigated the cues associated with the orientation of the generalist brood parasitoid Monodontomerus obscurus Westwood (Hymenoptera: Torymidae) to the nests of a common cavity-nesting resin bee Megachile campanulae (Robertson) (Megachilidae). The parasitoids were reared from previously infested M. campanulae brood cells and placed into choice trials where they were presented with pairs of different nest material cues. Among different materials tested, we found that Mo. obscurus was most attracted to fresh resin collected directly from Pinus strobus trees followed by previously used resin collected from the bee nest. The parasitoid also attacked other bee species in the same nest boxes, including those that do not use resin for nesting. Our findings suggest that M. campanulae could act as a magnet, drawing parasites away from other bee hosts co-occurring in nest boxes, or, as an attractant of Mo. obscurus to nest boxes, increasing attacks on co-occurring host bee species, potentially undermining bee diversity enhancement initiatives.

  8. Nested Potential Games

    OpenAIRE

    Hiroshi Uno

    2007-01-01

    This paper proposes a new class of potential games, the nested potential games, which generalize the potential games defined in Monderer and Shapley (1996), as well as the pseudo-potential games defined in Dubey et al. (2006). We show that each maximizer of a nested potential is a Nash equilibrium.

  9. Nesting ecology and nest survival of lesser prairie-chickens on the Southern High Plains of Texas

    Science.gov (United States)

    Grisham, Blake A.; Borsdorf, Philip K.; Boal, Clint W.; Boydston, Kathy K.

    2014-01-01

    The decline in population and range of lesser prairie-chickens (Tympanuchus pallidicinctus) throughout the central and southern Great Plains has raised concerns considering their candidate status under the United States Endangered Species Act. Baseline ecological data for lesser prairie-chickens are limited, especially for the shinnery oak-grassland communities of Texas. This information is imperative because lesser prairie-chickens in shinnery oak grasslands occur at the extreme southwestern edge of their distribution. This geographic region is characterized by hot, arid climates, less fragmentation, and less anthropogenic development than within the remaining core distribution of the species. Thus, large expanses of open rangeland with less anthropogenic development and a climate that is classified as extreme for ground nesting birds may subsequently influence nest ecology, nest survival, and nest site selection differently compared to the rest of the distribution of the species. We investigated the nesting ecology of 50 radio-tagged lesser prairie-chicken hens from 2008 to 2011 in the shinnery oak-grassland communities in west Texas and found a substantial amount of inter-annual variation in incubation start date and percent of females incubating nests. Prairie-chickens were less likely to nest near unimproved roads and utility poles and in areas with more bare ground and litter. In contrast, hens selected areas dominated by grasses and shrubs and close to stock tanks to nest. Candidate models including visual obstruction best explained daily nest survival; a 5% increase in visual obstruction improved nest survival probability by 10%. The model-averaged probability of a nest surviving the incubation period was 0.43 (SE = 0.006; 95% CI: 0.23, 0.56). Our findings indicate that lesser prairie-chicken reproduction during our study period was dynamic and was correlated with seasonal weather patterns that ultimately promoted greater grass growth earlier in the

  10. On evaluation of the nuclear interaction effect on muon sticking in μ-catalyzed dt synthesis

    International Nuclear Information System (INIS)

    Khiger, L.Ya.

    1994-01-01

    The effect of nucler interaction on the muon -alpha-particle sticking coefficient is considered on the basis of the previously developed formalism of description of the deuterium and tritium nuclei muon catalysed fusion. The account of Coulomb interaction between the muon and nuclear subsystem in the intermediate state is shown to change substantially this coefficient. The results of numerical calculations of the sticking coefficient are presented, the value of the coefficient turns out to be 3 - 4% higher than that found in the sudden approximation

  11. Differences in predators of artificial and real songbirds nests: Evidence of bias in artificial nest studies

    Science.gov (United States)

    Frank R. Thompson; Dirk E. Burhans

    2004-01-01

    In the past two decades, many researchers have used artificial nest to measure relative rates of nest predation. Recent comparisons show that real and artificial nests may not be depredated at the same rate, but no one has examined the mechanisms underlying these patterns. We determined differences in predator-specific predation rates of real and artificial nests. we...

  12. Conservation significance of alternative nests of golden eagles

    Directory of Open Access Journals (Sweden)

    Brian A. Millsap

    2015-01-01

    Full Text Available Golden eagles (Aquila chrysaetos are long-lived raptors that maintain nesting territories that may be occupied for a century or longer. Within occupied nesting territories there is one nest in which eagles lay their eggs in a given year (i.e., the used nest, but there are usually other nests (i.e., alternative nests. Conservation plans often protect used nests, but not alternative nests or nesting territories that appear vacant. Our objective is to review literature on golden eagle use of alternative nests and occupancy of nesting territories to determine if alternative nests are biologically significant and warrant greater conservation consideration. Our review shows that: (1 alternative nests or their associated habitat are most often in core areas of golden eagle nesting territories; (2 alternative nests likely will become used in the future; (3 probability of an alternative nest becoming used is greatest where prey availability is high and alternative nest sites are limited; (4 likelihood of annual occupancy or reoccupancy of golden eagle nesting territories is high; and (5 prey availability is the most important determinant of nesting territory occupancy and breeding activity. We recommend alternative nests be treated with the same deference as used nests in land use planning.

  13. Neste Corporation - a successful year

    International Nuclear Information System (INIS)

    Ihamuotila, J.

    1991-01-01

    The past year proved a successful one for Neste Corporation. Profitability was good and operations were consistently developed. Neste is committed to giving high priority to productivity and know- how to ensure that this success continues into the future. Important developments affecting the structure of Neste Corporation during 1990 included the amalgamation of Neste's oil-related activities into a single division, the increasing concentration of Neste Chemicals, activities in Central and Southern Europe and a major strengthening of oil exploration and production operations. Neste Oil turned in a good result during 1990. Neste imported a total of 8.9 million tonnes of crude oil during 1990. Imports from the Soviet Union at 5.2 million tonnes, were over 2 million tonnes less than planned. Some 2.5 million tonnes were imported from the North Sea, and 1.2 million tonnes from the Middle East. The year was one of expansion, diversification, and solid profit for Neste Chemicals. Net sales grew by 18 % compared to 1989 and the division recorded a satisfactory performance. Petrochemicals and polyolefins production increased suhstantially as a result of plants completed, acquired, or leased during 1989. The gas division's net sales during 1990 were 46 % higher than during 1989. This growth largely resulted from an increase in the consumption of natural gas and an expansion in the volume of international IPG business. The division's profitability remained satisfactory

  14. Columbia River ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for bird nesting sites in the Columbia River area. Vector points in this data set represent locations of...

  15. Changes in position and quality of preferred nest box: effects on nest box use by laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch; Nielsen, Birte L.

    2013-01-01

    Using laying hens, we investigated whether position of a nest box, both within the pen and relative to other nest boxes, influenced the preference for a nest box, and how a sudden and marked change to the preferred box influenced the use of nest boxes by the hens. Groups (n=12) of 15 Isa Warren...... hens were housed in pens, each with five identical nest boxes in different positions: Two single (in a corner or not) and a triplet of nest boxes (one of which in a corner). The use of nest boxes was determined by the number of eggs laid daily in each box. Three experiments, each lasting 10 days, were...... carried out. First, the undisturbed use of each of the nest box types was investigated, and a strong preference (Peggs laid there. Second, each of the hen groups was moved to another pen allocated at random, and where...

  16. Physicochemical and functional properties, microstructure, and storage stability of whey protein/polyvinylpyrrolidone based glue sticks

    Directory of Open Access Journals (Sweden)

    Guorong Wang

    2012-11-01

    Full Text Available A glue stick is comprised of solidified adhesive mounted in a lipstick-like push-up tube. Whey is a byproduct of cheese making. Direct disposal of whey can cause environmental pollution. The objective of this study was to use whey protein isolate (WPI as a natural polymer along with polyvinylpyrrolidone (PVP to develop safe glue sticks. Pre-dissolved WPI solution, PVP, sucrose, 1,2-propanediol (PG, sodium stearate, defoamer, and preservative were mixed and dissolved in water at 90 oC and then molded in push-up tubes. Chemical composition, functional properties (bonding strength, glue setting time, gel hardness, extension/retraction, and spreading properties, microstructure, and storage stability of the prototypes were evaluated in comparison with a commercial control. Results showed that all WPI/PVP prototypes had desirable bonding strength and exhibited faster setting than PVP prototypes and control. WPI could reduce gel hardness and form less compact and rougher structures than that of PVP, but there was no difference in bonding strength. PVP and sucrose could increase the hygroscopicity of glue sticks, thus increasing storage stability. Finally, the optimized prototype GS3 (major components: WPI 8.0%, PVP 12.0%, 1,2-propanediol 10.0%, sucrose 10.0%, and stearic sodium 7.0% had a comparable functionality to the commercial control. Results indicated that whey protein could be used as an adhesive polymer for glue stick formulations, which could be used to bond fiber or cellulose derived substrates such as paper.

  17. Development of Stick and Ball Sports on Gateball

    OpenAIRE

    Indriyanti; Tri Nur Harsono; Rumini

    2017-01-01

    The purpose of this research is to make product design development of stick and ball sports in gateball. The approach used in this study is a method of Research and Development. The subject of this research is the Central Java on gateball club event gateball in Semarang and Yogyakarta. Experts and expert expert gateball expert in mechanical engineering. The data analysis phase the work field, and the data analysis stage include observation, observation, interviews, and documentation of the te...

  18. The influence of regional hydrology on nesting behavior and nest fate of the American alligator

    Science.gov (United States)

    Ugarte, Cristina A.; Bass, Oron L.; Nuttle, William; Mazzotti, Frank J.; Rice, Kenneth G.; Fujisaki, Ikuko; Whelan, Kevin R.T.

    2013-01-01

    Hydrologic conditions are critical to the nesting behavior and reproductive success of crocodilians. In South Florida, USA, growing human settlement has led to extensive surface water management and modification of historical water flows in the wetlands, which have affected regional nesting of the American alligator (Alligator mississippiensis). Although both natural and anthropogenic factors are considered to determine hydrologic conditions, the aspects of hydrological patterns that affect alligator nest effort, flooding (partial and complete), and failure (no hatchling) are unclear. We deconstructed annual hydrological patterns using harmonic models that estimated hydrological matrices including mean, amplitude, timing of peak, and periodicity of surface water depth and discharge and examined their effects on alligator nesting using survey data from Shark Slough, Everglades National Park, from 1985 to 2005. Nest effort increased in years with higher mean and lesser periodicity of water depth. A greater proportion of nests were flooded and failed when peak discharge occurred earlier in the year. Also, nest flooding rates were greater in years with greater periodicity of water depth, and nest failure rate was greater when mean discharge was higher. This study guides future water management decisions to mitigate negative impacts on reproduction of alligators and provides wildlife managers with a tool for assessing and modifying annual water management plans to conserve crocodilians and other wetland species.

  19. Lack of nest site limitation in a cavity-nesting bird community

    Science.gov (United States)

    Jeffry R. Waters; Barry R. Noon; Jared Verner

    1990-01-01

    We examined the relationship between nest site availability and density of secondary cavitynesting birds by blocking cavities in an oak-pine (Quercus spp.-Pinus sp. ) woodland. In 1986 and 1987we blocked 67 and 106 cavities, respectively, on a 37-ha plot. The combined density of secondary cavity-nesting birds did not decline...

  20. A semi-analytical study of stick-slip oscillations in drilling systems

    NARCIS (Netherlands)

    Besselink, B.; Wouw, van de N.; Nijmeijer, H.

    2011-01-01

    Rotary drilling systems are known to exhibit torsional stick-slip vibrations, which decrease drilling efficiency and accelerate the wear of drag bits. The mechanisms leading to these torsional vibrations are analyzed using a model that includes both axial and torsional drill string dynamics, which

  1. Invasive rats strengthen predation pressure on bird eggs in a South Pacific island rainforest

    OpenAIRE

    Duron, Q.; Bourguet, E.; De Meringo, H.; Millon, A.; Vidal, Eric

    2017-01-01

    Invasive rats (Rattus spp.) are known to have pervasive impacts on island birds, particularly on their nesting success. To conserve or restore bird populations, numerous invasive rat control or eradication projects are undertaken on islands worldwide. However, such projects represent a huge investment and the decision-making process requires proper assessment of rat impacts. Here, we assessed the influence of two sympatric invasive rats (Rattus rattus and R. exulans) on native bird eggs in a ...

  2. Nesting biology of Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera, Crabronidae) in trap-nests in Southern Brazil.

    Science.gov (United States)

    Buschini, M L T; Niesing, F; Wolff, L L

    2006-08-01

    This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in diameter, respectively. They were constructed more often during the summer. T. lactitarse had two types of life cycles: direct development (without diapause), and delayed development (with diapause during winter). Natural enemies included Chrysididae, Sarcophagidae, Dolichopodidae and Ichneumonidae. Out of 1,353 identified spider prey, 1,313 belonged to the Araneidae family.

  3. Nesting biology of Trypoxylon (Trypargilum lactitarse Saussure (Hymenoptera, Crabronidae in trap-nests in Southern Brazil

    Directory of Open Access Journals (Sweden)

    M. L. T. Buschini

    Full Text Available This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in diameter, respectively. They were constructed more often during the summer. T. lactitarse had two types of life cycles: direct development (without diapause, and delayed development (with diapause during winter. Natural enemies included Chrysididae, Sarcophagidae, Dolichopodidae and Ichneumonidae. Out of 1,353 identified spider prey, 1,313 belonged to the Araneidae family.

  4. The Sticking Probability for Hydrogen on Ni, Pd, and Pt at a Hydrogen pressure of 1 bar

    DEFF Research Database (Denmark)

    Johansson, Martin; Lytken, Ole; Chorkendorff, Ib

    2007-01-01

    A technique for measurements of the sticking probability of hydrogen on metal surfaces at high (ambient) pressure is described. As an example, measurements for Ni, Pd and Pt at a hydrogen pressure of 1 bar and temperatures between 40 and 200 degrees C are presented. The sticking probabilities are......, Pt. The transition between beta- and alpha-phase in the H-Pd system has a significant effect on the activity for Pd....

  5. Nest design in a changing world: great tit Parus major nests from a Mediterranean city environment as a case study.

    Science.gov (United States)

    Lambrechts, Marcel M; Charmantier, Anne; Demeyrier, Virginie; Lucas, Annick; Perret, Samuel; Abouladzé, Matthieu; Bonnet, Michel; Canonne, Coline; Faucon, Virginie; Grosset, Stéphanie; le Prado, Gaëlle; Lidon, Frédéric; Noell, Thierry; Pagano, Pascal; Perret, Vincent; Pouplard, Stéphane; Spitaliéry, Rémy; Bernard, Cyril; Perret, Philippe; Blondel, Jacques; Grégoire, Arnaud

    2017-12-01

    Investigations of urbanization effects on birds have focused mainly on breeding traits expressed after the nest-building stage (e.g. first-egg date, clutch size, breeding success, and offspring characteristics). Urban studies largely ignored how and why the aspects of nest building might be associated with the degree of urbanization. As urban environments are expected to present novel environmental changes relative to rural environments, it is important to evaluate how nest-building behavior is impacted by vegetation modifications associated with urbanization. To examine nest design in a Mediterranean city environment, we allowed urban great tits ( Parus major ) to breed in nest boxes in areas that differed in local vegetation cover. We found that different measures of nest size or mass were not associated with vegetation cover. In particular, nests located adjacent to streets with lower vegetation cover were not smaller or lighter than nests in parks with higher vegetation cover. Nests adjacent to streets contained more pine needles than nests in parks. In addition, in nests adjacent to streets, nests from boxes attached to pine trees contained more pine needles than nests from boxes attached to other trees. We suggest that urban-related alterations in vegetation cover do not directly impose physical limits on nest size in species that are opportunistic in the selection of nesting material. However, nest composition as reflected in the use of pine needles was clearly affected by habitat type and the planted tree species present, which implies that rapid habitat change impacts nest composition. We do not exclude that urbanization might impact other aspects of nest building behaviour not covered in our study (e.g. costs of searching for nest material), and that the strengths of the associations between urbanization and nest structures might differ among study populations or species.

  6. Decoration Increases the Conspicuousness of Raptor Nests.

    Science.gov (United States)

    Canal, David; Mulero-Pázmány, Margarita; Negro, Juan José; Sergio, Fabrizio

    2016-01-01

    Avian nests are frequently concealed or camouflaged, but a number of species builds noticeable nests or use conspicuous materials for nest decoration. In most cases, nest decoration has a role in mate choice or provides thermoregulatory or antiparasitic benefits. In territorial species however, decorations may serve additional or complementary functions, such as extended phenotypic signaling of nest-site occupancy and social status to potential intruders. The latter may benefit both signaler and receiver by minimizing the risk of aggressive interactions, especially in organisms with dangerous weaponry. Support for this hypothesis was recently found in a population of black kites (Milvus migrans), a territorial raptor that decorates its nest with white artificial materials. However, the crucial assumption that nest decorations increased nest-site visibility to conspecifics was not assessed, a key aspect given that black kite nests may be well concealed within the canopy. Here, we used an unmanned aircraft system to take pictures of black kite nests, with and without an experimentally placed decoration, from different altitudes and distances simulating the perspective of a flying and approaching, prospecting intruder. The pictures were shown to human volunteers through a standardized routine to determine whether detection rates varied according the nest decoration status and distance. Decorated nests consistently showed a higher detection frequency and a lower detection-latency, compared to undecorated versions of the same nests. Our results confirm that nest decoration in this species may act as a signaling medium that enhances nest visibility for aerial receivers, even at large distances. This finding complements previous work on this communication system, which showed that nest decoration was a threat informing trespassing conspecifics on the social dominance, territory quality and fighting capabilities of the signaler.

  7. Nest defense behaviors of native cavity-nesting birds to European Starlings

    Science.gov (United States)

    Rodney G. Olsen; Kathryn L. Purcell; David. Grubbs

    2008-01-01

    We used behavioral experiments to evaluate competition for nest sites and the extent to which European Starlings (Sturnus vulgaris) are seen as a threat by native bird species at the San Joaquin Experimental Range, Madera County, CA. We quantified the level of aggressive behavior of four species of native cavity-nesting birds to starlings at active...

  8. Use of artificial nests to investigate predation on freshwater turtle nests

    Science.gov (United States)

    Michael N. Marchand; John A. Litvaitis; Thomas J. Maier; Richard M. DeGraaf

    2002-01-01

    Habitat fragmentation has raised concerns that populations of generalist predators have increased and are affecting a diverse group of prey. Previous research has included the use of artificial nests to investigate the role of predation on birds that nest on or near the ground. Because predation also is a major factor limiting populations of freshwater turtles, we...

  9. Interspecific nest use by aridland birds

    Science.gov (United States)

    Deborah M. Finch

    1982-01-01

    Nest holes drilled by woodpeckers (Picidae) are frequently used by secondary cavity-nesting species, but interspecific use of open and domed nests is less well known. Nests constructed by many southwestern desert birds last longer than one year (pers. obs.) and are consequently reused by the same pair (e.g., Abert's Towhees [Pipilo aberti], pers. obs.) or by other...

  10. Push-and-stick mechanism for charged and excited small cluster emission under ion bombardment

    International Nuclear Information System (INIS)

    Bitensky, I.S.; Parilis, E.S.; Wojciechowski, I.A.

    1992-01-01

    The mechanism for the formation, excitation and ionization of small clusters emitted under ion bombardment is discussed. It is shown that the increased degree of ionization for the transition metal dimers, trimers and tetramers can be explained by the existence of an additional effective channel for their formation, namely the associative ionization process. A simple estimate shows that the sticking together of a fast cascade atom and the pushed out surface atom is 30-40 times more effective for dimer formation, than the recombination of two fast atoms. This push-and-stick mechanism of cluster formation could also be effective for the formation of trimers and tetramers. (orig.)

  11. Evaluation of the dimethylglyoxime stick test for the detection of nickel

    DEFF Research Database (Denmark)

    Menné, T; Andersen, Klaus Ejner; Kaaber, K

    1987-01-01

    The value of the dimethylglyoxime stick test for the detection of nickel was determined for 54 randomly purchased metal objects designed for prolonged skin contact, and for 15 metal alloys of known composition. Surface nickel content was determined by EDAX analysis (energy dispersive X-ray) and n...

  12. The effect of vacuum packaging on histamine changes of milkfish sticks at various storage temperatures.

    Science.gov (United States)

    Kung, Hsien-Feng; Lee, Yi-Chen; Lin, Chiang-Wei; Huang, Yu-Ru; Cheng, Chao-An; Lin, Chia-Min; Tsai, Yung-Hsiang

    2017-10-01

    The effects of polyethylene packaging (PEP) (in air) and vacuum packaging (VP) on the histamine related quality of milkfish sticks stored at different temperatures (-20°C, 4°C, 15°C, and 25°C) were studied. The results showed that the aerobic plate count (APC), pH, total volatile basic nitrogen (TVBN), and histamine contents increased as storage time increased when the PEP and VP samples were stored at 25°C. At below 15°C, the APC, TVBN, pH, and histamine levels in PEP and VP samples were retarded, but the VP samples had considerably lower levels of APC, TVBN, and histamine than PEP samples. Once the frozen fish samples stored at -20°C for 2 months were thawed and stored at 25°C, VP retarded the increase of histamine in milkfish sticks as compared to PEP. In summary, this result suggested the milkfish sticks packed with VP and stored below 4°C could prevent deterioration of product quality and extend shelf-life. Copyright © 2017. Published by Elsevier B.V.

  13. Nesting biology of the trap-nesting Neotropical wasp Trypoxylo n(Trypargilum) aurifrons Shuckard (Hymenoptera, Crabronidae)

    OpenAIRE

    Santoni,Mariana Marchi; Del Lama,Marco Antonio

    2007-01-01

    The present study was carried out in three localities of the state of São Paulo, Brazil: Araras (Dec/03-Dec/06), São Carlos (Nov/04-Nov/06) and Rifaina (Jul/04-Dec/06). Trap-nests were distributed among sites in the sampling areas and were collected every 35 days. Data from 295 nests indicate that T. aurifrons is a multivoltine species, with higher rates of nest building and cell production in the warm, rainy season. The trap-nests used by the females ranged from 117 to 467 mm in length and 3...

  14. An unusual cause of duodenal perforation due to a lollipop stick

    Directory of Open Access Journals (Sweden)

    Mi Jin Kim

    2013-04-01

    Full Text Available Children have a natural tendency to explore objects with their mouths; this can result in the swallowing of foreign objects. Most ingested foreign bodies pass uneventfully through the gastrointestinal tract.However, some foreign bodies cause obstruction or perforation of the gastrointestinal tract, requiring surgical intervention. Perforation of the gastrointestinal tract may be associated with considerable morbidity and mortality. The most common sites of intestinal foreign body perforation are the ileocecal and rectosigmoid regions. Foreign body perforation of the duodenum is relatively uncommon. We report the first Korean case of duodenal perforation by an ingested 8-cm lollipop stick. Lollipops are popular with the children and fairly accessible to them, as most parents are not aware of their potential harm. Pediatric clinicians should be aware of the risks associated with lollipop stick ingestion. Our report also describes the feasibility and safety of laparoscopic diagnosis and management of pediatric patients with peritonitis induced by the ingestion of foreign bodies.

  15. Preliminary evaluation of a nest usage sensor to detect double nest occupations of laying hens.

    Science.gov (United States)

    Zaninelli, Mauro; Costa, Annamaria; Tangorra, Francesco Maria; Rossi, Luciana; Agazzi, Alessandro; Savoini, Giovanni

    2015-01-26

    Conventional cage systems will be replaced by housing systems that allow hens to move freely. These systems may improve hens' welfare, but they lead to some disadvantages: disease, bone fractures, cannibalism, piling and lower egg production. New selection criteria for existing commercial strains should be identified considering individual data about laying performance and the behavior of hens. Many recording systems have been developed to collect these data. However, the management of double nest occupations remains critical for the correct egg-to-hen assignment. To limit such events, most systems adopt specific trap devices and additional mechanical components. Others, instead, only prevent these occurrences by narrowing the nest, without any detection and management. The aim of this study was to develop and test a nest usage "sensor", based on imaging analysis, that is able to automatically detect a double nest occupation. Results showed that the developed sensor correctly identified the double nest occupation occurrences. Therefore, the imaging analysis resulted in being a useful solution that could simplify the nest construction for this type of recording system, allowing the collection of more precise and accurate data, since double nest occupations would be managed and the normal laying behavior of hens would not be discouraged by the presence of the trap devices.

  16. Preliminary Evaluation of a Nest Usage Sensor to Detect Double Nest Occupations of Laying Hens

    Directory of Open Access Journals (Sweden)

    Mauro Zaninelli

    2015-01-01

    Full Text Available Conventional cage systems will be replaced by housing systems that allow hens to move freely. These systems may improve hens’ welfare, but they lead to some disadvantages: disease, bone fractures, cannibalism, piling and lower egg production. New selection criteria for existing commercial strains should be identified considering individual data about laying performance and the behavior of hens. Many recording systems have been developed to collect these data. However, the management of double nest occupations remains critical for the correct egg-to-hen assignment. To limit such events, most systems adopt specific trap devices and additional mechanical components. Others, instead, only prevent these occurrences by narrowing the nest, without any detection and management. The aim of this study was to develop and test a nest usage “sensor”, based on imaging analysis, that is able to automatically detect a double nest occupation. Results showed that the developed sensor correctly identified the double nest occupation occurrences. Therefore, the imaging analysis resulted in being a useful solution that could simplify the nest construction for this type of recording system, allowing the collection of more precise and accurate data, since double nest occupations would be managed and the normal laying behavior of hens would not be discouraged by the presence of the trap devices.

  17. Nest densities of cavity-nesting birds in relation to postfire salvage logging and time since wildfire

    Science.gov (United States)

    Victoria A. Saab; Robin E. Russell; Jonathan G. Dudley

    2007-01-01

    We monitored the nest densities and nest survival of seven cavity-nesting bird species, including four open-space foragers (American Kestrel [Falco sparverius], Lewis's Woodpecker [Melanerpes lewis], Western Bluebird [Sialia mexicana], and Mountain Bluebird [S. currucoides]) and three wood...

  18. Contrasting Effects of Cattle Grazing Intensity on Upland-Nesting Duck Production at Nest and Field Scales in the Aspen Parkland, Canada

    Directory of Open Access Journals (Sweden)

    Jeffrey M. Warren

    2008-12-01

    Full Text Available The Aspen Parkland of Canada is one of the most important breeding areas for temperate nesting ducks in North America. The region is dominated by agricultural land use, with approximately 9.3 million ha in pasture land for cattle grazing. However, the effects of using land for cattle grazing on upland-nesting duck production are poorly understood. The current study was undertaken during 2001 and 2002 to investigate how nest density and nesting success of upland-nesting ducks varied with respect to the intensity of cattle grazing in the Aspen Parkland. We predicted that the removal and trampling of vegetation through cattle grazing would reduce duck nest density. Both positive and negative responses of duck nesting success to grazing have been reported in previous studies, leading us to test competing hypotheses that nesting success would (1 decline linearly with grazing intensity or (2 peak at moderate levels of grazing. Nearly 3300 ha of upland cover were searched during the study. Despite extensive and severe drought, nest searches located 302 duck nests. As predicted, nest density was higher in fields with lower grazing intensity and higher pasture health scores. A lightly grazed field with a pasture score of 85 out of a possible 100 was predicted to have 16.1 nests/100 ha (95% CI = 11.7-22.1, more than five times the predicted nest density of a heavily grazed field with a pasture score of 58 (3.3 nests/100 ha, 95% CI = 2.2-4.5. Nesting success was positively related to nest-site vegetation density across most levels of grazing intensity studied, supporting our hypothesis that reductions in vegetation caused by grazing would negatively affect nesting success. However, nesting success increased with grazing intensity at the field scale. For example, nesting success for a well-concealed nest in a lightly grazed field was 11.6% (95% CI = 3.6-25.0%, whereas nesting success for a nest with the same level of nest-site vegetation in a heavily grazed

  19. Coordination of the Walking Stick Insect Using a System of Nonlinear Coupled Oscillators

    National Research Council Canada - National Science Library

    Marvin, Daryl J

    1992-01-01

    The area of walking machines is investigated. A design for a central pattern generator composed of nonlinear coupled oscillators which generates the characteristic gaits of the walking stick insect is presented...

  20. Nesting ecology of Arctic loons

    Science.gov (United States)

    Petersen, Margaret R.

    1979-01-01

    Arctic Loons were studied on the Yukon-Kuskokwim Delta, Alaska, from the time of their arrival in May to their departure in September, in 1974 and 1975. Pairs arrived on breeding ponds as soon as sufficient meltwater was available to allow their take-off and landing. Loons apparently do not initiate nests immediately after their arrival, even when nest-sites are available. Delayed egg-laying may be dependent on a period of yolk formation. Delaying yolk formation until after arrival on nest ponds is an adaptation by loons to the variable time suitable habitat becomes available for nesting. Predation of eggs by Glaucous Gulls, Long-tailed and Parasitic jaegers and foxes varied in relation to the location of the nest-site, and the availability of alternate prey. Hatching success was the lowest recorded for Arctic Loons (5%) in 1974, when eggs of both loons and Cackling Geese were taken in large numbers by predators. Hatching success increased to 32% in 1975 when an abundance of tundra voles was observed. No loon eggs hatched after the hatching of the Cackling Goose eggs when this alternate prey was no longer available. Nests destroyed by foxes were predominantly along shorelines, and those by gulls and jaegers were predominantly on islands. Nest-site selection by Arctic Loons may reflect an adaptive response to varying selective pressures by their predators.

  1. Nest-site selection in the acorn woodpecker

    Science.gov (United States)

    Hooge, P.N.; Stanback, M.T.; Koenig, Walter D.

    1999-01-01

    Acorn Woodpeckers (Melanerpes formicivorus) at Hastings Reservation in central California prefer to nest in dead limbs in large, dead valley oaks (Quercus lobata) and California sycamores (Platanus racemosa) that are also frequently used as acorn storage trees. Based on 232 nest cavities used over an 18-year period, we tested whether preferred or modal nest-site characters were associated with increased reproductive success (the "nest-site quality" hypothesis). We also examined whether more successful nests were likely to experience more favorable microclimatic conditions or to be less accessible to terrestrial predators. We found only equivocal support for the nest-site quality hypothesis: only 1 of 5 preferred characters and 2 of 10 characters exhibiting a clear modality were correlated with higher reproductive success. All three characteristics of nests known or likely to be associated with a more favorable microclimate, and two of five characteristics likely to render nests less accessible to predators, were correlated with higher reproductive success. These results suggest that nest cavities in this population are built in part to take advantage of favorable microclimatic conditions and, to a lesser extent, to reduce access to predators. However, despite benefits of particular nest characteristics, birds frequently nested in apparently suboptimal cavities. We also found a significant relationship between mean group size and the history of occupancy of particular territories and the probability of nest cavities being built in microclimatically favorable live limbs, suggesting that larger groups residing on more stable territories were better able to construct nests with optimal characteristics. This indicates that there may be demographic, as well as ecological, constraints on nest-site selection in this primary cavity nester.

  2. Nest-site competition between invasive and native cavity nesting birds and its implication for conservation.

    Science.gov (United States)

    Charter, Motti; Izhaki, Ido; Ben Mocha, Yitzchak; Kark, Salit

    2016-10-01

    Nesting cavities are often a limited resource that multiple species use. There is an ongoing discussion on whether invasive cavity nesting birds restrict the availability of this key limited resource. While the answer to this question has important conservation implications, little experimental work has been done to examine it. Here, we aimed to experimentally test whether alien cavity nesting birds affect the occupancy of cavities and the resulting breeding success of native cavity breeders in a large urban park located in Tel Aviv, Israel. Over three breeding seasons, we manipulated the entry size of nest boxes and compared the occupancy and breeding success of birds in nest boxes of two treatments. These included nest boxes with large-entrance and small-entrance holes. The large-entrance holes allowed access for both the native and invasive birds (the two main aliens in the park are the common mynas and rose-ringed parakeets). The smaller-entrance boxes, on the other hand, allowed only the smaller sized native cavity breeders (great tits and house sparrows) to enter the boxes but prevented the alien species from entering. We found that the large-entrance nest boxes were occupied by five different bird species, comprising three natives (great tit, house sparrow, Scops owl) and two invasive species (common myna, rose-ringed parakeet) while the small-entrance boxes were only occupied by the two native species. The alien common mynas and rose-ringed parakeets occupied 77.5% of the large-entrance nest boxes whereas native species, mainly great tits, occupied less than 9% of the large-entrance boxes and 36.5% of the small-entrance boxes. When examining the occupancy of those cavities that were not occupied by the aliens, natives occupied both the small and large-entrance nest boxes equally. Three quarters (78%) of the great tits breeding in the large-entrance boxes were usurped by common mynas during the breeding season and as a result breeding success was

  3. Where to nest? Ecological determinants of chimpanzee nest abundance and distribution at the habitat and tree species scale.

    Science.gov (United States)

    Carvalho, Joana S; Meyer, Christoph F J; Vicente, Luis; Marques, Tiago A

    2015-02-01

    Conversion of forests to anthropogenic land-uses increasingly subjects chimpanzee populations to habitat changes and concomitant alterations in the plant resources available to them for nesting and feeding. Based on nest count surveys conducted during the dry season, we investigated nest tree species selection and the effect of vegetation attributes on nest abundance of the western chimpanzee, Pan troglodytes verus, at Lagoas de Cufada Natural Park (LCNP), Guinea-Bissau, a forest-savannah mosaic widely disturbed by humans. Further, we assessed patterns of nest height distribution to determine support for the anti-predator hypothesis. A zero-altered generalized linear mixed model showed that nest abundance was negatively related to floristic diversity (exponential form of the Shannon index) and positively with the availability of smaller-sized trees, reflecting characteristics of dense-canopy forest. A positive correlation between nest abundance and floristic richness (number of plant species) and composition indicated that species-rich open habitats are also important in nest site selection. Restricting this analysis to feeding trees, nest abundance was again positively associated with the availability of smaller-sized trees, further supporting the preference for nesting in food tree species from dense forest. Nest tree species selection was non-random, and oil palms were used at a much lower proportion (10%) than previously reported from other study sites in forest-savannah mosaics. While this study suggests that human disturbance may underlie the exclusive arboreal nesting at LCNP, better quantitative data are needed to determine to what extent the construction of elevated nests is in fact a response to predators able to climb trees. Given the importance of LCNP as refuge for Pan t. verus our findings can improve conservation decisions for the management of this important umbrella species as well as its remaining suitable habitats. © 2014 Wiley Periodicals, Inc.

  4. Ant colonies prefer infected over uninfected nest sites

    DEFF Research Database (Denmark)

    Pontieri, Luigi; Vojvodic, Svjetlana; Graham, Riley

    2014-01-01

    with sporulating mycelium of the entomopathogenic fungus Metarhizium brunneum (infected nests), nests containing nestmates killed by freezing (uninfected nests), and empty nests. In contrast to the expectation pharaoh ant colonies preferentially (84%) moved into the infected nest when presented with the choice...... the high risk of epidemics in group-living animals. Choosing nest sites free of pathogens is hypothesized to be highly efficient in invasive ants as each of their introduced populations is often an open network of nests exchanging individuals (unicolonial) with frequent relocation into new nest sites...... and low genetic diversity, likely making these species particularly vulnerable to parasites and diseases. We investigated the nest site preference of the invasive pharaoh ant, Monomorium pharaonis, through binary choice tests between three nest types: nests containing dead nestmates overgrown...

  5. Serenbe Nest Cottages

    Energy Technology Data Exchange (ETDEWEB)

    Butler, T.; Curtis, O.; Kim, E.; Roberts, S.; Stephenson, R.

    2012-12-01

    As part of the NAHB Research Center Industry Partnership, Southface partnered with Martin Dodson Builders and the Serenbe community on the construction of a new test home in the suburbs of Atlanta, GA in the mixed humid climate zone. The most recent subdivision within the Serenbe community, the Nest, will contain 15 small footprint cottage style homes, and Southface has selected Lot Nine, as the test home for this study. This Nest subdivision serves as a project showcase for both the builder partner and the Serenbe community as a whole. The planning and design incorporated into the Nest cottages will be implemented in each home within the subdivision. These homes addresses Building America Savings targets and serve as a basis of design for other homes Martin Dodson plans to build within the Serenbe community.

  6. Serenbe Nest Cottages

    Energy Technology Data Exchange (ETDEWEB)

    Butler, T. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Curtis, O. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Kim, E. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Roberts, S. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Stephenson, R. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2012-12-01

    As part of the NAHB Research Center Industry Partnership, Southface partnered with Martin Dodson Builders and the Serenbe community on the construction of a new test home in the suburbs of Atlanta, GA, in the mixed humid climate zone. The most recent subdivision within the Serenbe community, the Nest, will contain 15 small footprint cottage-style homes, and Southface has selected Lot Nine, as the test home for this study. This Nest subdivision serves as a project showcase for both the builder partner and the Serenbe community as a whole. The planning and design incorporated into the Nest cottages will be implemented in each home within the subdivision. These homes addresses Building America savings targets and serve as a basis of design for other homes Martin Dodson plans to build within the Serenbe community.

  7. Conservation significance of alternative nests of golden eagles

    Science.gov (United States)

    Brian A. Millsap; Teryl G. Grubb; Robert K. Murphy; Ted Swem; James W. Watson

    2015-01-01

    Golden eagles (Aquila chrysaetos) are long-lived raptors that maintain nesting territories that may be occupied for a century or longer. Within occupied nesting territories there is one nest in which eagles lay their eggs in a given year (i.e., the used nest), but there are usually other nests (i.e., alternative nests). Conservation plans often protect used nests, but...

  8. Nesting of the Blakiston's Fish-Owl in the Nest of the Steller’s Sea Eagle, Magadan Region, Russia

    Directory of Open Access Journals (Sweden)

    Irina G. Utekhina

    2016-04-01

    Full Text Available In 2015 one Steller’s Sea Eagle nest was occupied by a Blakiston’s Fish Owl, the first record of which came from the Nature Reserve Inspector, E.A. Stepanov, who, on May 17, noted the pair of fish owls near a Steller’s Sea Eagle nest on the western bank of the Chelomdja River, 3 km downstream from the Moldot ranger’s station. On that date one of the owls was sitting in the nest, and another was sitting in a tree nearby the nest. On May 26, E. Stepanov observed the owls in the same position. We observed the nest on 20 and 21 June 2015, and saw one large Blakiston’s Fish Owl chick in the nest; no adults were noted. Inspector A. Stepanov saw the chick in the nest on June 23, and an adult in a nearby.  Magadan State Reserve Inspector A. Akhanov reported that the nest was empty and no adults were seen on June 25.

  9. Carbon nanotube forests: a non-stick workbench for nanomanipulation

    International Nuclear Information System (INIS)

    Gjerde, Kjetil; Kjelstrup-Hansen, Jakob; Clausen, Casper H; Teo, Kenneth B K; Milne, William I; Rubahn, Horst-Guenter; Boeggild, Peter

    2006-01-01

    The ubiquitous static friction (stiction) and adhesion forces comprise a major obstacle in the manipulation of matter at the nanoscale (Falvo et al 1999 Nature 397 236; Urbakh M et al 2004 Nature 430 525). In this work it is shown that a surface coated with vertically aligned carbon nanotubes-a nanotube forest-acts as an effective non-stick workbench for the manipulation of micro-objects and fibres/wires with one or more dimensions in the nano-range. These include organic nanofibres (Balzer and Rubahn 2001 Appl. Phys. Lett. 79 3860) and microsized latex beads, which adhere strongly even to a conventional low surface-energy material like Teflon. Although organic nanofibres are attractive as device components due to their chemical adaptability, adhesion forces nearly always rule out manipulation as a route to assembly of prototype devices based on such materials, because organic materials are soft and fragile, and tend to stick to any surface. We demonstrate here that the nanotube forest due to its roughness not only exhibits very low stiction and dynamic friction; it also acts as a springy and mechanically compliant surface, making it possible to lift up and manipulate delicate nanostructures such as organic nanofibres in ways not possible on planar, rigid surfaces

  10. Nest site selection by Kentish plover suggests a trade-off between nest-crypsis and predator detection strategies.

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Gómez-Serrano

    Full Text Available Predation is one of the main causes of adult mortality and breeding failure for ground-nesting birds. Micro-habitat structure around nests plays a critical role in minimizing predation risk. Plovers nest in sites with little vegetation cover to maximize the incubating adult visibility, but many studies suggest a trade-off between nest-crypsis and predator detection strategies. However, this trade-off has not been explored in detail because methods used so far do not allow estimating the visibility with regards to critical factors such as slope or plant permeability to vision. Here, we tested the hypothesis that Kentish plovers select exposed sites according to a predator detection strategy, and the hypothesis that more concealed nests survive longer according to a crypsis strategy. To this end, we obtained an accurate estimation of the incubating adult's field of vision through a custom built inverted periscope. Our results showed that plovers selected nest sites with higher visibility than control points randomly selected with regards to humans and dogs, although nests located in sites with higher vegetation cover survived longer. In addition, the flushing distance (i.e., the distance at which incubating adults leave the nest when they detect a potential predator decreased with vegetation cover. Consequently, the advantages of concealing the nest were limited by the ability to detect predators, thus indirectly supporting the existence of the trade-off between crypsis and predator detection. Finally, human disturbance also constrained nest choice, forcing plovers to move to inland sites that were less suitable because of higher vegetation cover, and modulated flushing behavior, since plovers that were habituated to humans left their nests closer to potential predators. This constraint on the width of suitable breeding habitat is particularly relevant for the conservation of Kentish Plover in sand beaches, especially under the current context of

  11. Surface free energy of non-stick coatings deposited using closed field unbalanced magnetron sputter ion plating

    International Nuclear Information System (INIS)

    Sun, C.-C.; Lee, S.-C.; Dai, S.-B.; Tien, S.-L.; Chang, C.-C.; Fu, Y.-S.

    2007-01-01

    Semiconductor IC packaging molding dies require wear resistance, corrosion resistance and non-sticking (with a low surface free energy). The molding releasing capability and performance are directly associated with the surface free energy between the coating and product material. The serious sticking problem reduces productivity and reliability. Depositing TiN, TiMoS, ZrN, CrC, CrN, NiCr, NiCrN, CrTiAlN and CrNiTiAlN coatings using closed field unbalanced magnetron sputter ion plating, and characterizing their surface free energy are the main object in developing a non-stick coating system for semiconductor IC molding tools. The contact angle of water, diiodomethane and ethylene glycol on the coated surfaces were measured at temperature in 20 deg. C using a Dataphysics OCA-20 contact angle analyzer. The surface free energy of the coatings and their components (dispersion and polar) were calculated using the Owens-Wendt geometric mean approach. The surface roughness was investigated by atomic force microscopy (AFM). The adhesion force of these coatings was measured using direct tensile pull-off test apparatus. The experimental results showed that NiCrN, CrN and NiCrTiAlN coatings outperformed TiN, ZrN, NiCr, CiTiAlN, CrC and TiMoS coatings in terms of non-sticking, and thus have the potential as working layers for injection molding industrial equipment, especially in semiconductor IC packaging molding applications

  12. Strong selection on mandible and nest features in a carpenter bee that nests in two sympatric host plants

    OpenAIRE

    Flores-Prado, Luis; Pinto, Carlos F; Rojas, Alejandra; Fontúrbel, Francisco E

    2014-01-01

    Host plants are used by herbivorous insects as feeding or nesting resources. In wood-boring insects, host plants features may impose selective forces leading to phenotypic differentiation on traits related to nest construction. Carpenter bees build their nests in dead stems or dry twigs of shrubs and trees; thus, mandibles are essential for the nesting process, and the nest is required for egg laying and offspring survival. We explored the shape and intensity of natural selection on phenotypi...

  13. Habitat structure and diversity influence the nesting success of an endangered large cavity-nesting bird, the Southern Ground-hornbill

    Directory of Open Access Journals (Sweden)

    Leigh Combrink

    2017-11-01

    Full Text Available Habitat features can have a profound effect on the nesting success of birds. Savannas are often managed with predators and large herbivores as priority species, with little thought to the many bird species that management decisions could affect. Using a data set spanning seven breeding seasons, we examined how nesting success of Southern Ground-hornbills (SGHs Bucorvus leadbeateri in the Kruger National Park varied as a result of various environmental and habitat factors within a radius of 3 km surrounding the nest site. Identifying which factors affect nesting success will allow for targeted management efforts to ensure the long-term survival of SGHs both within and outside of protected areas. Habitat structure and diversity of the vegetation surrounding the nest were the most influential factors on SGH nesting success. SGHs require open grassy areas for foraging and areas with large trees for nesting. Savanna habitat drivers such as elephants and fire should be managed to ensure that sufficient large trees are able to establish in the landscape and to control for bush encroachment. This is especially important in areas earmarked for SGH reintroductions. Nest sites of SGHs should be monitored to mitigate any structural changes in the habitat surrounding the nests. Nests should be modified or artificial nest sites provided, where nests have been damaged or lost, to ensure the continued presence of these birds in African savannas. Conservation implications: Habitat structure and diversity surrounding Southern Groundhornbill nests has a significant impact on their nesting success. This highlights the importance of monitoring vegetation change in savanna habitats where they occur. Management of savanna areas should take factors that influence bush encroachment, such as fire and elephants, into account to ensure the long-term persistence of these birds.

  14. Repeatability of nest morphology in African weaver birds.

    Science.gov (United States)

    Walsh, Patrick T; Hansell, Mike; Borello, Wendy D; Healy, Susan D

    2010-04-23

    It is generally assumed that birds build nests according to a genetic 'template', little influenced by learning or memory. One way to confirm the role of genetics in nest building is to assess the repeatability of nest morphology with repeated nest attempts. Solitary weaver birds, which build multiple nests in a single breeding season, are a useful group with which to do this. Here we show that repeatability of nest morphology was low, but significant, in male Southern Masked weaver birds and not significant in the Village weavers. The larger bodied Village weavers built larger nests than did Southern Masked weavers, but body size did not explain variation in Southern Masked weaver nest dimensions. Nests built by the same male in both species got shorter and lighter as more nests were constructed. While these data demonstrate the potential for a genetic component of variation in nest building in solitary weavers, it is also clear that there remains plenty of scope in both of these species for experience to shape nest construction.

  15. Nest Construction by a Ground-nesting Bird Represents a Potential Trade-off Between Egg Crypticity and Thermoregulation

    Science.gov (United States)

    Predation selects against conspicuous colors in bird eggs and nests, while thermoregulatory constraints select for nest building behavior that regulates incubation temperatures. We present results that reveal a trade-off between nest crypticity and thermoregulation of eggs base...

  16. Sensitivity of Coastal Environments and Wildlife to Spilled Oil: New Hampshire: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting birds in New Hampshire. Vector points in this data set represent locations of nesting osprey...

  17. Burrow architecture of the Damaraland mole-rat ( Fukomys ...

    African Journals Online (AJOL)

    The burrow architecture (length, internal dimensions, fractal dimension of tunnel systems, number of nesting chambers and surface mounds) was investigated in the Damaraland mole-rat (Fukomys damarensis). A total of 31 animals were caught from five different colonies and their burrow systems were excavated in their ...

  18. CPW-fed Circularly Polarized Slot Antenna with Small Gap and Stick-shaped Shorted Strip for UHF FRID Readers

    Science.gov (United States)

    Pan, Chien-Yuan; Su, Chum-Chieh; Yang, Wei-Lin

    2018-04-01

    A new circularly polarized (CP) slot antenna with a small gap and a stick-shaped shorted strip is presented. The proposed antenna has a sufficient bandwidth for ultrahigh frequency (UHF) radio-frequency identification (RFID) reader applications. The antenna structure consists of a rectangular slot with a small gap, a stick-shaped shorted strip and a 50 Ω coplanar waveguide (CPW) feedline with an asymmetrical ground plane. By using the stick -shaped shorted strip to disturb magnetic current distribution on the slot, the CP radiation can be generated. The measured results demonstrate that the proposed antenna can reach a 10 dB return loss impedance bandwidth of 14.1 % (894-1030 MHz) and a 3 dB axial ratio (AR) bandwidth of 6.4 % (910-970 MHz). The whole antenna size is 80 × 80 × 1.6 mm3.

  19. Nest trampling and ground nesting birds: Quantifying temporal and spatial overlap between cattle activity and breeding redshank.

    Science.gov (United States)

    Sharps, Elwyn; Smart, Jennifer; Mason, Lucy R; Jones, Kate; Skov, Martin W; Garbutt, Angus; Hiddink, Jan G

    2017-08-01

    Conservation grazing for breeding birds needs to balance the positive effects on vegetation structure and negative effects of nest trampling. In the UK, populations of Common redshank Tringa totanus breeding on saltmarshes declined by >50% between 1985 and 2011. These declines have been linked to changes in grazing management. The highest breeding densities of redshank on saltmarshes are found in lightly grazed areas. Conservation initiatives have encouraged low-intensity grazing at nest trampling. If livestock distribution is not spatially or temporally homogenous but concentrated where and when redshank breed, rates of nest trampling may be much higher than expected based on livestock density alone. By GPS tracking cattle on saltmarshes and monitoring trampling of dummy nests, this study quantified (i) the spatial and temporal distribution of cattle in relation to the distribution of redshank nesting habitats and (ii) trampling rates of dummy nests. The distribution of livestock was highly variable depending on both time in the season and the saltmarsh under study, with cattle using between 3% and 42% of the saltmarsh extent and spending most their time on higher elevation habitat within 500 m of the sea wall, but moving further onto the saltmarsh as the season progressed. Breeding redshank also nest on these higher elevation zones, and this breeding coincides with the early period of grazing. Probability of nest trampling was correlated to livestock density and was up to six times higher in the areas where redshank breed. This overlap in both space and time of the habitat use of cattle and redshank means that the trampling probability of a nest can be much higher than would be expected based on standard measures of cattle density. Synthesis and applications : Because saltmarsh grazing is required to maintain a favorable vegetation structure for redshank breeding, grazing management should aim to keep livestock away from redshank nesting habitat between mid

  20. The design and function of birds' nests

    Science.gov (United States)

    Mainwaring, Mark C; Hartley, Ian R; Lambrechts, Marcel M; Deeming, D Charles

    2014-01-01

    All birds construct nests in which to lay eggs and/or raise offspring. Traditionally, it was thought that natural selection and the requirement to minimize the risk of predation determined the design of completed nests. However, it is becoming increasingly apparent that sexual selection also influences nest design. This is an important development as while species such as bowerbirds build structures that are extended phenotypic signals whose sole purpose is to attract a mate, nests contain eggs and/or offspring, thereby suggesting a direct trade-off between the conflicting requirements of natural and sexual selection. Nest design also varies adaptively in order to both minimize the detrimental effects of parasites and to create a suitable microclimate for parents and developing offspring in relation to predictable variation in environmental conditions. Our understanding of the design and function of birds' nests has increased considerably in recent years, and the evidence suggests that nests have four nonmutually exclusive functions. Consequently, we conclude that the design of birds' nests is far more sophisticated than previously realized and that nests are multifunctional structures that have important fitness consequences for the builder/s. PMID:25505520

  1. The design and function of birds' nests.

    Science.gov (United States)

    Mainwaring, Mark C; Hartley, Ian R; Lambrechts, Marcel M; Deeming, D Charles

    2014-10-01

    All birds construct nests in which to lay eggs and/or raise offspring. Traditionally, it was thought that natural selection and the requirement to minimize the risk of predation determined the design of completed nests. However, it is becoming increasingly apparent that sexual selection also influences nest design. This is an important development as while species such as bowerbirds build structures that are extended phenotypic signals whose sole purpose is to attract a mate, nests contain eggs and/or offspring, thereby suggesting a direct trade-off between the conflicting requirements of natural and sexual selection. Nest design also varies adaptively in order to both minimize the detrimental effects of parasites and to create a suitable microclimate for parents and developing offspring in relation to predictable variation in environmental conditions. Our understanding of the design and function of birds' nests has increased considerably in recent years, and the evidence suggests that nests have four nonmutually exclusive functions. Consequently, we conclude that the design of birds' nests is far more sophisticated than previously realized and that nests are multifunctional structures that have important fitness consequences for the builder/s.

  2. Estimating raptor nesting success: old and new approaches

    Science.gov (United States)

    Brown, Jessi L.; Steenhof, Karen; Kochert, Michael N.; Bond, Laura

    2013-01-01

    Studies of nesting success can be valuable in assessing the status of raptor populations, but differing monitoring protocols can present unique challenges when comparing populations of different species across time or geographic areas. We used large datasets from long-term studies of 3 raptor species to compare estimates of apparent nest success (ANS, the ratio of successful to total number of nesting attempts), Mayfield nesting success, and the logistic-exposure model of nest survival. Golden eagles (Aquila chrysaetos), prairie falcons (Falco mexicanus), and American kestrels (F. sparverius) differ in their breeding biology and the methods often used to monitor their reproduction. Mayfield and logistic-exposure models generated similar estimates of nesting success with similar levels of precision. Apparent nest success overestimated nesting success and was particularly sensitive to inclusion of nesting attempts discovered late in the nesting season. Thus, the ANS estimator is inappropriate when exact point estimates are required, especially when most raptor pairs cannot be located before or soon after laying eggs. However, ANS may be sufficient to assess long-term trends of species in which nesting attempts are highly detectable.

  3. Response of beach-nesting American Oystercatchers to off-road vehicles: An experimental approach reveals physiological nuances and decreased nest attendance

    Science.gov (United States)

    Felton, Shilo K.; Pollock, Kenneth H.; Simons, Theodore R.

    2018-01-01

    Shorebird populations face increasing challenges as rising sea levels and growing human populations constrain their breeding habitats. On recreational beaches, the nesting season often coincides with a season of high visitor use, increasing the potential for conflict, which may negatively influence beach-nesting shorebird species. We designed a field experiment to study the responses of nesting American Oystercatchers (Haematopus palliatus) to off-road passenger vehicles (ORVs) at Cape Hatteras and Cape Lookout National Seashores in North Carolina, USA. We used continuous video and heart rate recordings to assess changes in the behavior and physiology of incubating oystercatchers. We conducted driving experiments affecting 7 nesting pairs in 2014 and 19 nesting pairs in 2015, between April and July of each year. Experimental treatments were repeated throughout the incubation period for each nest. Although responses were highly variable within and among pairs, paired randomized permutation tests indicated that, overall, oystercatcher pairs spent a greater proportion of time with their heads up and exhibited slower heart rates during driving treatments. Pairs also left their nests more frequently and attended their nests for a lower proportion of time during driving treatments, although these responses diminished over time. Higher nest attendance and lower departure rates late in incubation may have reflected a stronger attachment to nests closer to hatching or habituation to the driving treatment, although individuals continued to exhibit physiological responses to passing vehicles throughout incubation. Beach-nesting birds may benefit from reduced vehicle traffic at their nesting sites, allowing parents to spend more time attending the nest and less time on defensive behaviors.

  4. Creep and stick-slip in subglacial granular beds forced by ocean tides

    DEFF Research Database (Denmark)

    Damsgaard, Anders; Egholm, David Lundbek; Beem, Lucas H.

    and laboratory experiments provide important constraints, but existing models have not been able to explain the internal processes driving transitions from stability to stick-slip within the sediment. In this presentation we use a coupled numerical model of grain and fluid dynamics to show that rapid...

  5. Grain scale observations of stick-slip dynamics in fluid saturated granular fault gouge

    Science.gov (United States)

    Johnson, P. A.; Dorostkar, O.; Guyer, R. A.; Marone, C.; Carmeliet, J.

    2017-12-01

    We are studying granular mechanics during slip. In the present work, we conduct coupled computational fluid dynamics (CFD) and discrete element method (DEM) simulations to study grain scale characteristics of slip instabilities in fluid saturated granular fault gouge. The granular sample is confined with constant normal load (10 MPa), and sheared with constant velocity (0.6 mm/s). This loading configuration is chosen to promote stick-slip dynamics, based on a phase-space study. Fluid is introduced in the beginning of stick phase and characteristics of slip events i.e. macroscopic friction coefficient, kinetic energy and layer thickness are monitored. At the grain scale, we monitor particle coordination number, fluid-particle interaction forces as well as particle and fluid kinetic energy. Our observations show that presence of fluids in a drained granular fault gouge stabilizes the layer in the stick phase and increases the recurrence time. In saturated model, we observe that average particle coordination number reaches higher values compared to dry granular gouge. Upon slip, we observe that a larger portion of the granular sample is mobilized in saturated gouge compared to dry system. We also observe that regions with high particle kinetic energy are correlated with zones of high fluid motion. Our observations highlight that spatiotemporal profile of fluid dynamic pressure affects the characteristics of slip instabilities, increasing macroscopic friction coefficient drop, kinetic energy release and granular layer compaction. We show that numerical simulations help characterize the micromechanics of fault mechanics.

  6. EFL Students' and Teachers' Attitudes toward Foreign Language Speaking Anxiety: A Look at NESTs and Non-NESTs

    Science.gov (United States)

    Han, Turgay; Tanriöver, Ahmet Serkan; Sahan, Özgür

    2016-01-01

    Native English Speaking Teachers (NESTs) have been employed in various English language teaching (ELT) positions and departments at private and state universities in Turkey, particularly over the last three decades. However, undergraduate EFL students' attitudes toward NESTs and Non-Native English Speaking Teachers (Non-NESTs) remain seriously…

  7. Copper accumulation by stickleback nests containing spiggin.

    Science.gov (United States)

    Pinho, G L L; Martins, C M G; Barber, I

    2016-07-01

    The three-spined stickleback is a ubiquitous fish of marine, brackish and freshwater ecosystems across the Northern hemisphere that presents intermediate sensitivity to copper. Male sticklebacks display a range of elaborate reproductive behaviours that include nest construction. To build the nests, each male binds nesting material together using an endogenous glycoprotein nesting glue, known as 'spiggin'. Spiggin is a cysteine-rich protein and, therefore, potentially binds heavy metals present in the environment. The aim of this study was to investigate the capacity of stickleback nests to accumulate copper from environmental sources. Newly built nests, constructed by male fish from polyester threads in laboratory aquaria, were immersed in copper solutions ranging in concentration from 21.1-626.6 μg Cu L(-1). Bundles of polyester threads from aquaria without male fish were also immersed in the same copper solutions. After immersion, nests presented higher amounts of copper than the thread bundles, indicating a higher capacity of nests to bind this metal. A significant, positive correlation between the concentration of copper in the exposure solution and in the exposed nests was identified, but there was no such relationship for thread bundles. Since both spiggin synthesis and male courtship behaviour are under the control of circulating androgens, we predicted that males with high courtship scores would produce and secrete high levels of the spiggin protein. In the present study, nests built by high courtship score males accumulated more copper than those built by low courtship score males. Considering the potential of spiggin to bind metals, the positive relationship between fish courtship and spiggin secretion seems to explain the higher amount of copper on the nests from the fish showing high behaviour scores. Further work is now needed to determine the consequences of the copper binding potential of spiggin in stickleback nests for the health and survival of

  8. Construction patterns of birds' nests provide insight into nest-building behaviours

    OpenAIRE

    Biddle, Lucia; Goodman, Adrian; Deeming, Charles

    2017-01-01

    Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in a...

  9. Constructing bald eagle nests with natural materials

    Science.gov (United States)

    T. G. Grubb

    1995-01-01

    A technique for using natural materials to build artificial nests for bald eagles (Haliaeetus leucocephalus) and other raptors is detailed. Properly constructed nests are as permanently secured to the nest tree or cliff substrate as any eagle-built nest or human-made platform. Construction normally requires about three hours and at least two people. This technique is...

  10. Light pollution affects nesting behavior of loggerhead turtles and predation risk of nests and hatchlings.

    Science.gov (United States)

    Silva, Elton; Marco, Adolfo; da Graça, Jesemine; Pérez, Héctor; Abella, Elena; Patino-Martinez, Juan; Martins, Samir; Almeida, Corrine

    2017-08-01

    The introduction of artificial light into wildlife habitats is a rapidly expanding aspect of global change, which has many negative impacts on a wide range of taxa. In this experimental study, which took place on a beach located on the island of Boa Vista (Cabo Verde), three types of artificial light were tested on nesting loggerhead sea turtles as well as on ghost crabs, which intensively predate on nests and hatchlings, to determine the effects they would produce on the behavior of both species. Over the course of 36days, female loggerheads and ghost crabs were studied under yellow, orange and red lights, with observations also being made on dark nights that served as a control treatment. During this period, the frequencies of nesting attempts, the time taken by turtles to complete each phase of the nesting process, and ghost crab abundance and behaviors were carefully recorded. 1146 loggerhead nesting attempts were observed and recorded during the experiments, and results showed a decrease in nesting attempts of at least 20% when artificial lighting was present. A significant decline in successful attempts was also observed within the central sections of the beach, which corresponded to those that received more light. This artificial lighting significantly increased the time that turtles spent on the nesting process and forced them to do more extensive beach crawls. Despite this, the presence of light had no apparent effect on the final selection of the nesting site. Yellow and orange lights significantly disrupted the sea finding behavior and turtles were often unable to orient themselves seaward under these color lights. Disoriented turtles were observed crawling in circuitous paths in front of the light source for several minutes. In addition, artificial lights had the potential to increase the number of ghost crabs present within the illuminated stretches of the beach. However, only yellow lighting produced a significant change on aggressive and prey

  11. Bristol Bay, Alaska Subarea ESI: NESTS (Nest Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting seabirds (alcids, pelagic birds), gulls, terns, diving birds, and raptors in the Bristol Bay...

  12. Strong selection on mandible and nest features in a carpenter bee that nests in two sympatric host plants.

    Science.gov (United States)

    Flores-Prado, Luis; Pinto, Carlos F; Rojas, Alejandra; Fontúrbel, Francisco E

    2014-05-01

    Host plants are used by herbivorous insects as feeding or nesting resources. In wood-boring insects, host plants features may impose selective forces leading to phenotypic differentiation on traits related to nest construction. Carpenter bees build their nests in dead stems or dry twigs of shrubs and trees; thus, mandibles are essential for the nesting process, and the nest is required for egg laying and offspring survival. We explored the shape and intensity of natural selection on phenotypic variation on three size measures of the bees (intertegular width, wing length, and mandible area) and two nest architecture measures (tunnel length and diameter) on bees using the native species Chusquea quila (Poaceae), and the alloctonous species Rubus ulmifolius (Rosaceae), in central Chile. Our results showed significant and positive linear selection gradients for tunnel length on both hosts, indicating that bees building long nests have more offspring. Bees with broader mandibles show greater fitness on C. quila but not on R. ulmifolius. Considering that C. quila represents a selective force on mandible area, we hypothesized a high adaptive value of this trait, resulting in higher fitness values when nesting on this host, despite its wood is denser and hence more difficult to be bored.

  13. Changes in Quality Properties and Kinetics of Reducing Sugar Removal in Potato Sticks during Blanching

    Directory of Open Access Journals (Sweden)

    M. Asadi

    2015-01-01

    Full Text Available Due to problems in storage, transportation and price fluctuation of fresh potato, production of ready-to-use products like French fries is of particular importance. French fries quality mainly depends on the appearance, taste, color, texture and oil uptake. One of the important steps in product processing is blanching. This step improves product texture and color due to the decrease in reducing sugar content, and causes reduction of oil uptake due to the gelatinization of surface starch. Therefore, by selecting a suitable method and condition, the improvement of product quality is possible. In order to investigate the effect of blanching temperature on kinetic of the reducing sugar content and changes in potato stick color and texture, sticks with 0.8 0.8 8 cm dimensions were prepared and blanching was carried out with hot water at different temperatures (60, 70, 80 and 90°C and various times up to 120 minutes. Color, texture and reducing sugar content of samples were measured during blanching. The results showed that reducing sugar content was reduced during the blanching as a function of temperature and time. Also, product color and texture were mainly affected by blanching temperature, with the low temperature being more suitable to improve potato stick quality. According to the results, there was no significant difference between blanching at 80, 90°C and 60°C for reducing sugar content. Also, for this parameter, there was no significant difference between times of 100 and 5 minutes at 60°C. The least texture damage was obtained by blanching at 60°C in a short time. It could be concluded that to preserve potato stick color and texture and reduce energy consumption, blanching can be done at 60°C for 5 minutes if enzymes are inactivated.

  14. Preference of rabbit does among different nest materials

    Directory of Open Access Journals (Sweden)

    T.P. Farkas

    2018-03-01

    Full Text Available Nest quality is important for the survival of new-born rabbits. Nesting material in rabbit farms generally consists of wood shavings, which is completely different from the dry grass used by the European wild rabbit (Oryctolagus cuniculus. The aim of the experiments was to examine which nest materials are preferred by rabbit does when building their nest. In experiment 1, the choice of multiparous rabbit does (n=37 among nest boxes bedded with different nesting materials was monitored. In each pen (1.0×1.83 m 1 doe and 4 nest boxes (0.37×0.23×0.31 m with different nest materials (meadow hay [H], wheat straw [S], fine fibre material [Lignocel®, L] or wood shavings [W] were placed 3 days before the expected parturition (gestation length is about 31 d in the Pannon White breed. Some 48.6% of the does kindled in nest boxes that contained pure materials (L: 40.5%, S: 5.4%, H: 2.7%, and 51.3% of the does kindled in nest boxes where the nest materials of different nest boxes were mixed by the does (S with L: 21.5%, S with L and H: 5.4%, W with L: 8.1%, L with H and S: 5.4%. Does preferred kindling in the nest box bedded with L, and most of them refused the nest box with W. In experiment 2/a (n=32 does and 2/b (n=25 does, each pen (1×0.91 m was equipped with 3 and 2 hay racks and filled with H, S or L, and H or S, respectively. The experiments lasted from the 27th day of pregnancy until the day of parturition and 24-h video recordings (10 does/experiment were evaluated throughout the experiment. The events of carrying the nest materials from the hay racks were registered. In experiment 2/a, the frequency of nest material carrying was highest on the day of parturition. The preferred nest material was L (compared to H and S on each experimental day except day 30 of pregnancy. At the day of kindling, 87.5, 6.3 and 6.3% of the nests contained pure L, mixed L-H and L-S, respectively. In experiment 2/b, the frequency of nest material carrying (mostly S

  15. Stick-slip behaviour of a viscoelastic flat sliding along a rigid indenter

    NARCIS (Netherlands)

    Budi Setiyana, Budi; Ismail, Rifky; Jamari, J.; Schipper, Dirk Jan

    2016-01-01

    The sliding contact of soft material surface due to a rigid indenter is different from metal and some other polymers. A stick-slip motion is more frequently obtained than a smooth motion. By modeling the soft material as low damping viscoelastic material, this study proposes an analytical model to

  16. Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests.

    Science.gov (United States)

    Giroux, Marie-Andrée; Trottier-Paquet, Myriam; Bêty, Joël; Lamarre, Vincent; Lecomte, Nicolas

    2016-01-01

    Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica) defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter "conspicuous behaviour"), as well as more aggressive behaviours such as aerial attacks, but only in some populations. Such antipredator behaviour has the potential to repel predators and thus benefit the neighbouring nests by decreasing their predation risk. Yet, conspicuous behaviour could also attract predators by signalling the presence of a nest. To test for the existence of a protective effect associated with the conspicuous antipredator behaviour of American Golden-Plovers, we studied the influence of proximity to plover nests on predation risk of artificial nests on Igloolik Island (Nunavut, Canada) in July 2014. We predicted that the predation risk of artificial nests would decrease with proximity to and density of plover nests. We monitored 18 plover nests and set 35 artificial nests at 30, 50, 100, 200, and 500 m from seven of those plover nests. We found that the predation risk of artificial nests increases with the density of active plover nests. We also found a significant negative effect of the distance to the nearest active protector nest on predation risk of artificial nests. Understanding how the composition and structure of shorebird communities generate spatial patterns in predation risks represents a key step to better understand the importance of these species of conservation concern in tundra food webs.

  17. Low heritability of nest construction in a wild bird.

    Science.gov (United States)

    Järvinen, Pauliina; Kluen, Edward; Brommer, Jon E

    2017-10-01

    In birds and other taxa, nest construction varies considerably between and within populations. Such variation is hypothesized to have an adaptive (i.e. genetic) basis, but estimates of heritability in nest construction are largely lacking. Here, we demonstrate with data collected over 10 years from 1010 nests built by blue tits in nest-boxes that nest size (height of nest material) and nest composition (proportion of feathers in the nest) are repeatable but only weakly (12-13%) heritable female traits. These findings imply that nest construction may evolve but only if subjected to strong and consistent selection pressures. © 2017 The Author(s).

  18. Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests

    Directory of Open Access Journals (Sweden)

    Marie-Andrée Giroux

    2016-08-01

    Full Text Available Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter “conspicuous behaviour”, as well as more aggressive behaviours such as aerial attacks, but only in some populations. Such antipredator behaviour has the potential to repel predators and thus benefit the neighbouring nests by decreasing their predation risk. Yet, conspicuous behaviour could also attract predators by signalling the presence of a nest. To test for the existence of a protective effect associated with the conspicuous antipredator behaviour of American Golden-Plovers, we studied the influence of proximity to plover nests on predation risk of artificial nests on Igloolik Island (Nunavut, Canada in July 2014. We predicted that the predation risk of artificial nests would decrease with proximity to and density of plover nests. We monitored 18 plover nests and set 35 artificial nests at 30, 50, 100, 200, and 500 m from seven of those plover nests. We found that the predation risk of artificial nests increases with the density of active plover nests. We also found a significant negative effect of the distance to the nearest active protector nest on predation risk of artificial nests. Understanding how the composition and structure of shorebird communities generate spatial patterns in predation risks represents a key step to better understand the importance of these species of conservation concern in tundra food webs.

  19. Hierarchically nested river landform sequences

    Science.gov (United States)

    Pasternack, G. B.; Weber, M. D.; Brown, R. A.; Baig, D.

    2017-12-01

    River corridors exhibit landforms nested within landforms repeatedly down spatial scales. In this study we developed, tested, and implemented a new way to create river classifications by mapping domains of fluvial processes with respect to the hierarchical organization of topographic complexity that drives fluvial dynamism. We tested this approach on flow convergence routing, a morphodynamic mechanism with different states depending on the structure of nondimensional topographic variability. Five nondimensional landform types with unique functionality (nozzle, wide bar, normal channel, constricted pool, and oversized) represent this process at any flow. When this typology is nested at base flow, bankfull, and floodprone scales it creates a system with up to 125 functional types. This shows how a single mechanism produces complex dynamism via nesting. Given the classification, we answered nine specific scientific questions to investigate the abundance, sequencing, and hierarchical nesting of these new landform types using a 35-km gravel/cobble river segment of the Yuba River in California. The nested structure of flow convergence routing landforms found in this study revealed that bankfull landforms are nested within specific floodprone valley landform types, and these types control bankfull morphodynamics during moderate to large floods. As a result, this study calls into question the prevailing theory that the bankfull channel of a gravel/cobble river is controlled by in-channel, bankfull, and/or small flood flows. Such flows are too small to initiate widespread sediment transport in a gravel/cobble river with topographic complexity.

  20. Common cuckoos Cuculus canorus change their nest-searching strategy according to the number of available host nests

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Václav; Procházka, Petr; Požgayová, Milica; Honza, Marcel

    2014-01-01

    Roč. 156, č. 1 (2014), s. 189-197 ISSN 0019-1019 R&D Projects: GA AV ČR IAA600930605; GA AV ČR IAA600930903 Institutional support: RVO:68081766 Keywords : brood parasitism * cuckoo perch * edge effect host aggression * host choice * nest height * nest visibility * nest volume Subject RIV: EG - Zoology Impact factor: 1.921, year: 2014

  1. Experimental evidence of reduced sticking of nanoparticles on a metal grid

    NARCIS (Netherlands)

    Gulijk, C. van; Bal, E.A.; Schmidt-Ott, A.

    2009-01-01

    Filtering of NaCl, CaCl2, (NH4)2SO4 and NiSO4 aerosol particles 7–20 nm in diameter by a stainless steel grid was studied in order to find out if there is perfect sticking or partial rebound. Our experiment used particles from a spray-drying process, the majority of which were electrically neutral.

  2. Science 101: Why Don't Spiders Stick to Their Own Webs?

    Science.gov (United States)

    Robertson, Bill

    2011-01-01

    This article explains why spiders don't stick to their webs. Spiders don't get stuck in their own webs (and they aren't immune to their own glue) because they use a combination of sticky and nonsticky threads (different glands for producing those), and the glue is in droplets that the spider can avoid but the prey can't. The spider's nervous…

  3. An economical wireless cavity-nest viewer

    Science.gov (United States)

    Daniel P. Huebner; Sarah R. Hurteau

    2007-01-01

    Inspection of cavity nests and nest boxes is often required during studies of cavity-nesting birds, and fiberscopes and pole-mounted video cameras are sometimes used for such inspection. However, the cost of these systems may be prohibitive for some potential users. We describe a user-built, wireless cavity viewer that can be used to access cavities as high as 15 m and...

  4. Nesting Biology and Occurrence of Social Nests in a Bivoltine and Basically Solitary Halictine Bee, Lasioglossum (Lasioglossum) scitulum Smith (Hymenoptera : Halictidae)

    OpenAIRE

    Ryoichi, MIYANAGA; Yasuo, MAETA; Kazuo, HOSHIKAWA; Division of Environmental Biology, Faculty of Life and Environmental Science, Shimane University; Division of Environmental Biology, Faculty of Life and Environmental Science, Shimane University; Division of Environmental Biology, Faculty of Life and Environmental Science, Shimane University

    2000-01-01

    The life cycle and sociality of the halictine bee, Lasioglossum (Lasioglossum) scitulum were studied in a greenhouse at Matsue (lat. 35°22′N), south-western Japan in 1988 and 1989. This species was a bivoltine bee with solitary to primitively social behavior. During the summer brooding period of 1988, 51 solitary nests and 8 multi-female nests (3 matrifilial and 5 sororal nests) were discovered. In 1989, 11 multi-female nests (3 matrifilial and 8 sororal nests), together with 59 solitary nest...

  5. StickOn Adhesive Limited: A Strategic Pursuit in Challenging Environment

    OpenAIRE

    Sumita Rai; Ashok Banerjee

    2012-01-01

    This case focuses upon the issues that have arisen as StickOn Adhesive Limited (SOAL) faces the challenges of competition in the industry through two-pronged strategies — backward integration and product diversification. The case discusses various initiatives taken by SOAL to meet strategic goals. SOAL has initiated changes in its marketing policies, re-layered the organization structure, and empowered the internal management to realize growth objectives. The case examines the corporate dilem...

  6. Premonitory acoustic emissions and stick-slip in natural and smooth-faulted Westerly granite

    Science.gov (United States)

    Thompson, B.D.; Young, R.P.; Lockner, David A.

    2009-01-01

    A stick-slip event was induced in a cylindrical sample of Westerly granite containing a preexisting natural fault by loading at constant confining pressure of 150 MPa. Continuously recorded acoustic emission (AE) data and computer tomography (CT)-generated images of the fault plane were combined to provide a detailed examination of microscale processes operating on the fault. The dynamic stick-slip event, considered to be a laboratory analog of an earthquake, generated an ultrasonic signal that was recorded as a large-amplitude AE event. First arrivals of this event were inverted to determine the nucleation site of slip, which is associated with a geometric asperity on the fault surface. CT images and AE locations suggest that a variety of asperities existed in the sample because of the intersection of branch or splay faults with the main fault. This experiment is compared with a stick-slip experiment on a sample prepared with a smooth, artificial saw-cut fault surface. Nearly a thousand times more AE were observed for the natural fault, which has a higher friction coefficient (0.78 compared to 0.53) and larger shear stress drop (140 compared to 68 MPa). However at the measured resolution, the ultrasonic signal emitted during slip initiation does not vary significantly between the two experiments, suggesting a similar dynamic rupture process. We propose that the natural faulted sample under triaxial compression provides a good laboratory analogue for a field-scale fault system in terms of the presence of asperities, fault surface heterogeneity, and interaction of branching faults. ?? 2009.

  7. The efficacy of mechanical vibration analgesia for relief of heel stick pain in neonates: a novel approach.

    Science.gov (United States)

    Baba, Lisa R; McGrath, Jacqueline M; Liu, Jiexin

    2010-01-01

    Hospitalized infants are often exposed to many painful procedures as a result of their illness or disease process. Untreated or poorly treated pain can have deleterious effects on normal nociceptive pain development as well as future development of pain pathways. Mechanical vibration has been found to be efficacious in adult and pediatric populations for the relief of mild-to-moderate acute and chronic pain. However, little is known about the efficacy of this intervention in the neonatal population. The purpose of this study was to test the hypothesis that mechanical vibration would be efficacious in the relief of pain associated with heel sticks in neonates. Heel sticks are one of the most common painful procedures during neonatal hospitalization. A random-sequencing crossover design was used with infants acting as their own controls. Newborn infants of 35 weeks' gestation or greater (N = 20) met the inclusion criteria for the study. Pain during heel stick was measured with the Neonatal Infant Pain Scale. The Neonatal Infant Pain Scale is a nonintrusive tool with extensive evidence of its reliability and validity in the neonatal population, when used by trained observers. Mechanical vibration produced an analgesic effect for infants who had previously experienced painful heel sticks that approached statistical significance. The apparent limitations of mechanical vibration as analgesia may be due to the concurrent use of sucrose and pacifier, the effects of order (ie, habituation), or type II error. Because vibration produced the predicted positive effect in some circumstances, further investigation in larger samples within a randomized clinical trial is warranted.

  8. Stick-Slip Motion of Moving Contact Line on Chemically Patterned Surfaces

    KAUST Repository

    Wu, Congmin; Lei, Siulong; Qian, Tiezheng; Wang, Xiaoping

    2009-01-01

    Based on our continuum hydrodynamic model for immiscible two-phase flows at solid surfaces, the stick-slip motion has been predicted for moving contact line at chemically patterned surfaces [Wang et al., J. Fluid Mech., 605 (2008), pp. 59-78]. In this paper we show that the continuum predictions can be quantitatively verified by molecular dynamics (MD) simulations. Our MD simulations are carried out for two immiscible Lennard-Jones fluids confined by two planar solid walls in Poiseuille flow geometry. In particular, one solid surface is chemically patterned with alternating stripes. For comparison, the continuum model is numerically solved using material parameters directly measured in MD simulations. From oscillatory fluid-fluid interface to intermittent stick-slip motion of moving contact line, we have quantitative agreement between the continuum and MD results. This agreement is attributed to the accurate description down to molecular scale by the generalized Navier boundary condition in our continuum model. Numerical results are also presented for the relaxational dynamics of fluid-fluid interface, in agreement with a theoretical analysis based on the Onsager principle of minimum energy dissipation. © 2010 Global-Science Press.

  9. Subterranean ant nests: Trace fossils past and future?

    OpenAIRE

    Tschinkel, Walter R.

    2003-01-01

    Many species of ants excavate complex, species-typical nests in soil. The basic structural units of many nests are descending tunnels connecting flattened, generally horizontal chambers of oval to lobed outline. The species-typical structure of many nests results from variation in the size, shape, number and arrangement of these basic elements. Nest architecture can be rendered by filling subterranean nests with a thin slurry of orthodontal plaster, then excavating and reconstructing the hard...

  10. Stick and feel system design: Systèmes de restitution des efforts au manche

    National Research Council Canada - National Science Library

    Gibson, J. C; Hess, R. A

    1997-01-01

    Since the earliest days of manned flight, designers have to sought to assist the pilot in the performance of tasks by using stick and feel systems to bring these tasks within the bounds of human physical capabilities...

  11. Converting nested algebra expressions into flat algebra expressions

    NARCIS (Netherlands)

    Paredaens, J.; Van Gucht, D.

    1992-01-01

    Nested relations generalize ordinary flat relations by allowing tuple values to be either atomic or set valued. The nested algebra is a generalization of the flat relational algebra to manipulate nested relations. In this paper we study the expressive power of the nested algebra relative to its

  12. Phytoplankton aggregate formation: observations of patterns and mechanisms of cell sticking and the significance of exopolymeric material

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Hansen, Jorgen L. S.

    1993-01-01

    are sticky in themselves, and coagulation depends on cell-cell sticking and does not involve mucus. Aggregates are composed solely of cells. Cells of the diatom Chaetoceros affinis, on the other hand, are not in themselves sticky. Transparent exopolymeric particles (TEP), produced by the diatom, cause...... the cells to aggregate and coagulation depends on TEP-cell rather than cell-cell sticking. Aggregates are formed of a mixture of mucus and cells. We found several species of diatoms and one flagellate species to produce copious amounts of TEP. TEP from some species (e.g. Coscinodiscus sp.) is sticky and may...

  13. Does removal of mammalian predators significantly affect success of simulated nests in linear habitats? Case study on American mink Mustela vison \\& Predation on simulated duck nests in relation to nest density and habitat type

    OpenAIRE

    PADYŠÁKOVÁ, Eliška

    2007-01-01

    This thesis is made up of two studies dealing with predation of waterfowl nests. in the first study, we determined wheather removal of introduced predator Mustela vison affected nest survival of simulated duck nests in linear habitat. In the second study, we tested two hypothesis: 1)predation depends on density of waterfowl nests, 2)mammals are main predators in forest habitat and birds mainly depredate nests deployed in open land.

  14. Biology of a trap-nesting wasp of one species the ground-nesting Liris (Hymenoptera: Crabronidae from the Atlantic Forest of southern Brazil

    Directory of Open Access Journals (Sweden)

    Camila Cristina Ferreira da Costa

    Full Text Available ABSTRACT Studies on the nesting biology of Liris are restricted to a few notes and observations on ground-nesting species. There are no studies of this kind about Brazilian species. We investigated and described the nesting biology of Liris sp. obtained by trap-nests that were installed at an area of Atlantic Forest vegetation (25°10'S, 48°18'W in southern Brazil. The nests of Liris sp. are built with a variety of plant debris. They usually have one cell, but may have up to two. Nests do not show vestibular or intercalary cells. Immatures have a hard cocoon made with the silk they produce, mixed with the fine sand and sawdust left by the adult female at the bottom of the cell. No nest parasites were observed. The wasps did not go through diapause at the prepupal stage, and emerged within 36 to 46 days after nests were collected from the field. There was no emergence of male wasps. Even though Liris sp. nest in preexisting cavities, they resemble ground-nesting species of the same genus in their habits, nest architecture, and development characteristics. The absence of males in our samples might be related to nest diameter. The eggs from which males hatch can be laid in smaller burrows than those available at the present study. We believe that the hardiness of the cocoon is the species' main strategy against parasites, although it is complemented by the camouflage provided by the nest closure. We suggest that a broader comparison of the nesting biology of Liris Fabricius, 1804 should be carried out, leading to a better understanding of the evolution of nests in the genus.

  15. Sexual odor discrimination and physiological profiles in adult male rats after a neonatal, short term, reversible nasal obstruction.

    Science.gov (United States)

    Thornton, S N; Padzys, G S; Trabalon, M

    2014-05-01

    The present study was designed to examine behavioral responses (interpreted as preferences) to olfactory cues (nest bedding odor and odors of estrous and anestrus females) in adult male rats after they had a short term reversible, bilateral, nasal obstruction (RbNO) as developing rat pups. These results were compared to behavior of control (untreated) and sham operated male littermates. Behavioral tests and physiological parameters were analyzed 90 days after recovery of nasal breathing. Experiments investigated the time spent in arms or the center of a maze of male rats in response to odors from the nest bedding or from adult females. There were no differences in responses between untreated, sham and RbNO adult male rats to fresh and nest bedding odors. RbNO males spent more time in the center of the maze when given a choice of estrus or anestrus female odors, or bedding odors from untreated or sham operated female rats. In contrast untreated and sham male rats preferred the odors of estrous females and of untreated or sham females. Plasma corticosterone levels in the males increased during the behavioral tests. Plasma testosterone levels were significantly lower in RbNO males compared to untreated males and did not increase during the behavioral tests compared to sham operated males. Males from all groups had similar preferences for the odor of bedding from adult RbNO females. Plasma levels of cholesterol and triglycerides were increased in RbNO adults. In conclusion, short term nasal obstruction in males while juvenile has long term consequences on hormones and behavioral preferences, thus potential partner selection when adult. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Analysis of bit-rock interaction during stick-slip vibrations using PDC cutting force model

    Energy Technology Data Exchange (ETDEWEB)

    Patil, P.A.; Teodoriu, C. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE

    2013-08-01

    Drillstring vibration is one of the limiting factors maximizing the drilling performance and also causes premature failure of drillstring components. Polycrystalline diamond compact (PDC) bit enhances the overall drilling performance giving the best rate of penetrations with less cost per foot but the PDC bits are more susceptible to the stick slip phenomena which results in high fluctuations of bit rotational speed. Based on the torsional drillstring model developed using Matlab/Simulink for analyzing the parametric influence on stick-slip vibrations due to drilling parameters and drillstring properties, the study of relations between weight on bit, torque on bit, bit speed, rate of penetration and friction coefficient have been analyzed. While drilling with the PDC bits, the bit-rock interaction has been characterized by cutting forces and the frictional forces. The torque on bit and the weight on bit have both the cutting component and the frictional component when resolved in horizontal and vertical direction. The paper considers that the bit is undergoing stick-slip vibrations while analyzing the bit-rock interaction of the PDC bit. The Matlab/Simulink bit-rock interaction model has been developed which gives the average cutting torque, T{sub c}, and friction torque, T{sub f}, values on cutters as well as corresponding average weight transferred by the cutting face, W{sub c}, and the wear flat face, W{sub f}, of the cutters value due to friction.

  17. Harpy eagle (Harpia harpyja) nesting in manipulated forests

    Science.gov (United States)

    Alvarez, E.; Ellis, D.H.

    1994-01-01

    Continental records point to shooting, removal of young and destruction of nests as the primary conservation problems for harpy eagles (Harpia harpyja); bird-observer visits are a new source of concern. Nesting events are roughly 3 yr apart. Nests are used during and after intensive manipulation of the surrounding habitat, and minimum distance between active sites was 3-5 km. In nine nesting sites along a 100-km stretch of the Imalaca Mountains in Venezuela, we fitted five fledglings with satellite-tracked tags from NASA. One of these birds was hacked with the help of the loggers who destroyed its nest. All these nests were active while logging ensued. Out of three renesting attempts, one failed when the nest collapsed. We salvaged two additional fledglings found in captivity. We are monitoring five nests in the buffer area of the Darien National Park in Panama, all within 3 km of human settlements where trees are regularly felled for firewood, lumber, and to clear more cropland. Eagles have been killed at two sites, a third site remains inactive since 1991, and the other two nests currently have fledglings.

  18. Simulating large-scale spiking neuronal networks with NEST

    OpenAIRE

    Schücker, Jannis; Eppler, Jochen Martin

    2014-01-01

    The Neural Simulation Tool NEST [1, www.nest-simulator.org] is the simulator for spiking neural networkmodels of the HBP that focuses on the dynamics, size and structure of neural systems rather than on theexact morphology of individual neurons. Its simulation kernel is written in C++ and it runs on computinghardware ranging from simple laptops to clusters and supercomputers with thousands of processor cores.The development of NEST is coordinated by the NEST Initiative [www.nest-initiative.or...

  19. Peeling-angle dependence of the stick-slip instability during adhesive tape peeling.

    Science.gov (United States)

    Dalbe, Marie-Julie; Santucci, Stéphane; Vanel, Loïc; Cortet, Pierre-Philippe

    2014-12-28

    The influence of peeling angle on the dynamics observed during the stick-slip peeling of an adhesive tape has been investigated. This study relies on a new experimental setup for peeling at a constant driving velocity while keeping constant the peeling angle and peeled tape length. The thresholds of the instability are shown to be associated with a subcritical bifurcation and bistability of the system. The velocity onset of the instability is moreover revealed to strongly depend on the peeling angle. This could be the consequence of peeling angle dependance of either the fracture energy of the adhesive-substrate joint or the effective stiffness at play between the peeling front and the point at which the peeling is enforced. The shape of the peeling front velocity fluctuations is finally shown to progressively change from typical stick-slip relaxation oscillations to nearly sinusoidal oscillations as the peeling angle is increased. We suggest that this transition might be controlled by inertial effects possibly associated with the propagation of the peeling force fluctuations through elongation waves in the peeled tape.

  20. Jordan Isomorphisms on Nest Subalgebras

    Directory of Open Access Journals (Sweden)

    Aili Yang

    2015-01-01

    Full Text Available This paper is devoted to the study of Jordan isomorphisms on nest subalgebras of factor von Neumann algebras. It is shown that every Jordan isomorphism ϕ between the two nest subalgebras algMβ and algMγ is either an isomorphism or an anti-isomorphism.

  1. Gregarious nesting - An anti-predator response in laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch

    2012-01-01

    Gregarious nesting can be defined as a behaviour that occurs when a laying hen (Gallus gallus domesticus) given the choice between an occupied and an unoccupied nest site chooses the occupied nest site. It occurs frequently in flocks of laying hens kept under commercial conditions, contrasting...... the behaviour displayed by feral hens that isolate themselves from the flock during nesting activities. What motivates laying hens to perform gregarious nesting is unknown. One possibility is that gregarious nesting is an anti-predator response to the risk of nest predation emerging from behavioural flexibility...

  2. Trap-nests for stingless bees (Hymenoptera, Meliponini)

    OpenAIRE

    Oliveira , Ricardo; Menezes , Cristiano; Soares , Ademilson; Fonseca , Vera

    2012-01-01

    International audience; Most stingless bee species build their nests inside tree hollows. In this paper, we present trap-nest containers which simulate nesting cavities so as to attract swarms of stingless bees. Although regularly used by stingless bee beekeepers in Brazil, this technique to obtain new colonies has not yet been systematically studied. We used two different types of trap-nests (plastic and cardboard) of four different sizes (0.5, 1.0, 2.0, and 3.0 L) containing propolis extrac...

  3. Effect of nest design, passages, and hybrid on use of nest and production performance of layers in furnished cages.

    Science.gov (United States)

    Wall, H; Tauson, R; Elwinger, K

    2002-03-01

    Production performance, including egg quality, and proportion of eggs laid in nests were studied in furnished experimental cages incorporating nests, litter baths, and perches. The study comprised a total of 972 hens of two genotypes: Lohmann Selected Leghorn (LSL) and Hy-Line White. The birds were studied from 20 to 80 wk of age, and conventional four-hen cages were included as a reference. In furnished cages for six hens, the effects of 30 or 50% vs. 100% nest bottom lining (Astro turf) were studied with LSL hens. Nest bottom lining had no significant effect on egg production or proportions of cracked or dirty eggs, but the use of nests was significantly higher in cages incorporating nests with 100% lining, compared with 50 or 30%. The two hybrids were compared when housed in large, group-furnished cages for 14 or 16 hens of two designs; with a rear partition with two pop holes or fully open, i.e., no rear partition. LSL birds produced significantly better and had a significantly lower proportion of cracked eggs. There was no difference between H- and O-cages, either in production or in egg quality. LSL birds laid a significantly lower proportion of eggs in the nests, especially in O-cages, implying a significant hybrid x cage interaction. When housed in conventional cages, the hybrids did not differ in proportion of cracked eggs but differed in production traits. It was concluded that with the present nest design, the proportion of nest bottom lining cannot be reduced without affecting birds' use of nests, but the proportion did not affect exterior egg quality. The effect of genotype should be considered in the further development of furnished cages.

  4. Nesting success and within-season breeding dispersal in the ...

    African Journals Online (AJOL)

    Nest predation is a primary cause of nesting mortality for many bird species, particularly passerines. Nest location can affect predation, and it has also been demonstrated that predation risk can alter nest site selection. Birds can limit predation risk by selecting specific habitat characteristics; by changing nest site ...

  5. Colour preferences in nest-building zebra finches.

    Science.gov (United States)

    Muth, Felicity; Steele, Matthew; Healy, Susan D

    2013-10-01

    Some bird species are selective in the materials they choose for nest building, preferring, for example, materials of one colour to others. However, in many cases the cause of these preferences is not clear. One of those species is the zebra finch, which exhibits strong preferences for particular colours of nest material. In an attempt to determine why these birds strongly prefer one colour of material over another, we compared the preferences of paired male zebra finches for nest material colour with their preferences for food of the same colours. We found that birds did indeed prefer particular colours of nest material (in most cases blue) but that they did not generally prefer food of one colour over the other colours. It appears, then, that a preference for one colour or another of nest material is specific to the nest-building context. This article is part of a Special Issue entitled: insert SI title. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Landscape distribution of food and nesting sites affect larval diet and nest size, but not abundance of Osmia bicornis.

    Science.gov (United States)

    Coudrain, Valérie; Rittiner, Sarah; Herzog, Felix; Tinner, Willy; Entling, Martin H

    2016-10-01

    Habitat fragmentation is a major threat for beneficial organisms and the ecosystem services they provide. Multiple-habitat users such as wild bees depend on both nesting and foraging habitat. Thus, they may be affected by the fragmentation of at least two habitat types. We investigated the effects of landscape-scale amount of and patch isolation from both nesting habitat (woody plants) and foraging habitat (specific pollen sources) on the abundance and diet of Osmia bicornis L. Trap-nests of O. bicornis were studied in 30 agricultural landscapes of the Swiss Plateau. Nesting and foraging habitats were mapped in a radius of 500 m around the sites. Pollen composition of larval diet changed as isolation to the main pollen source, Ranunculus, increased, suggesting that O. bicornis adapted its foraging strategy in function of the nest proximity to main pollen sources. Abundance of O. bicornis was neither related to isolation or amount of nesting habitat nor to isolation or abundance of food plants. Surprisingly, nests of O. bicornis contained fewer larvae in sites at forest edge compared to isolated sites, possibly due to higher parasitism risk. This study indicates that O. bicornis can nest in a variety of situations by compensating scarcity of its main larval food by exploiting alternative food sources. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  7. Turkey habitat use and nesting characteristics in ponderosa pine

    Science.gov (United States)

    Mark A. Rumble; Stanley H. Anderson

    1987-01-01

    Turkeys (Meleagris gallapovo) selected nest sites that provided good horizontal concealment. Rock or rock outcrops were selected most frequently for nest concealment on first-nest attempts. Renest attempts showed a selection preference for shrubs as nest cover; most of these were located in meadows. Nesting success doubled for renests versus first...

  8. Response of predators to Western Sandpiper nest exclosures

    Science.gov (United States)

    Niehaus, Amanda C.; Ruthrauff, Daniel R.; McCaffery, Brian J.

    2004-01-01

    In 2001, predator exclosures were used to protect nests of the Western Sandpiper (Calidris mauri) in western Alaska. During the exclosure experiment, nest contents in exclosures had significantly higher daily survival rates than control nests, however, late in the study predators began to cue in on exclosures and predate the nest contents. An Arctic Fox (Alopex lagopus) dug under one exclosure and took the newly hatched chicks, and Long-tailed Jaegers (Stercorarius longicaudus) learned to associate exclosures with active nests and repeatedly visited them. The jaegers attempted to gain access to exclosed nests and pursued adult sandpipers as they emerged from the exclosures. The exclosures were removed to reduce potential mortality to adult and young sandpipers, but subsequently, post-exclosure nests had lower daily survival rates than controls during the same time period. Predation of post-exclosure eggs and chicks highlighted the lasting influence of the exclosure treatment on offspring survival because predators probably remembered nest locations. Researchers are urged to use caution when considering use of predator exclosures in areas where jaegers occur.

  9. Incorporation of cigarette butts into nests reduces nest ectoparasite load in urban birds: new ingredients for an old recipe?

    Science.gov (United States)

    Suárez-Rodríguez, Monserrat; López-Rull, Isabel; Garcia, Constantino Macías

    2013-02-23

    Birds are known to respond to nest-dwelling parasites by altering behaviours. Some bird species, for example, bring fresh plants to the nest, which contain volatile compounds that repel parasites. There is evidence that some birds living in cities incorporate cigarette butts into their nests, but the effect (if any) of this behaviour remains unclear. Butts from smoked cigarettes retain substantial amounts of nicotine and other compounds that may also act as arthropod repellents. We provide the first evidence that smoked cigarette butts may function as a parasite repellent in urban bird nests. The amount of cellulose acetate from butts in nests of two widely distributed urban birds was negatively associated with the number of nest-dwelling parasites. Moreover, when parasites were attracted to heat traps containing smoked or non-smoked cigarette butts, fewer parasites reached the former, presumably due to the presence of nicotine. Because urbanization changes the abundance and type of resources upon which birds depend, including nesting materials and plants involved in self-medication, our results are consistent with the view that urbanization imposes new challenges on birds that are dealt with using adaptations evolved elsewhere.

  10. Development by extrusion of soyabari snack sticks: a nutritionally improved soya-maize product based on the Nigerian snack (kokoro).

    Science.gov (United States)

    Omueti, O; Morton, I D

    1996-01-01

    A nutritionally improved local snack compared to existing kokoro has been developed by extrusion cooking of different formulations of maize, soybean and condiments such as pepper, onion, salt, palm oil, plantain and banana. The improved snack was named as the 'soyabari snack stick'. The chemical composition of representative extruded products indicates a high level of crude protein, fat, energy, available lysine and improved in vitro digestibility compared to the usual maize-based products. The level of stachyose and raffinose were greatly reduced in the extruded products compared to raw soya. Formulations using various additives yielded products suitable for different consumers' preferences such as hot, sweet, bland, gritty or crispy and acceptable to taste assessors. Soyabari snack sticks were equally acceptable as Bombay mix, a product on the market in London. Sensory analysis showed no significant differences in the two products but the crude fibre content of Bombay mix was higher while the protein was slightly lower than for soyabari sticks. Local ingredients can produce acceptable extrudates.

  11. Semantic Analysis of Virtual Classes and Nested Classes

    DEFF Research Database (Denmark)

    Madsen, Ole Lehrmann

    1999-01-01

    Virtual classes and nested classes are distinguishing features of BETA. Nested classes originated from Simula, but until recently they have not been part of main stream object- oriented languages. C++ has a restricted form of nested classes and they were included in Java 1.1. Virtual classes...... classes and parameterized classes have been made. Although virtual classes and nested classes have been used in BETA for more than a decade, their implementation has not been published. The purpose of this paper is to contribute to the understanding of virtual classes and nested classes by presenting...

  12. Demand for Neste's City products grows strongly

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    Finland's oil, chemicals, and gas company, Neste Corporation, is well on the road to better financial performance after a very difficult year in 1992. Among the factors contributing to this optimism are Neste's pioneering low environmental impact traffic fuels. Neste Corporation's net sales in 1993 rose 9.9 % on 1992 figures to USD 11,011 million. Investments totalled USD 681 million. Profitability also improved during 1993, and the operating margin rose by 57 %, despite the recession affecting the Finnish economy and the instability of the international market. The operational loss for the year before extraordinary items, reserves, and taxes was USD 265 million, one-third less than in 1992. Neste's strategy has been to achieve a strong position in the Baltic Rim region by becoming the quality and cost leader in oil refining, and by expanding Neste's position in its key markets. A total of 3.3 million tonnes of petroleum products were exported from Finland in 1993. Neste's most important export markets were Sweden, Germany, Poland, the Baltic countries, and the St. Petersburg region. Some 20 % of exports went to customers outside Europe. In addition to Finland, Neste has concertedly developed its service station network in Poland and the Baltic countries

  13. UBV-photometry of nests of interacting galaxies

    International Nuclear Information System (INIS)

    Arkhipova, V.P.

    1982-01-01

    The results of photoelectric UBV-observations of 19 nests of interacting galaxies, made at the Crimean Station of the Sternberg Institute, are given. Most of the nests observed were found to be and to have high luminosity. The UBV and spectral data show a large amount of gas inside many nests [ru

  14. Eggshell Porosity Provides Insight on Evolution of Nesting in Dinosaurs.

    Directory of Open Access Journals (Sweden)

    Kohei Tanaka

    Full Text Available Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1 covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes, and 2 open nests, in which eggs are exposed in the nest and brooded (as in most birds. Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1 covered nests are likely the primitive condition for dinosaurs (and probably archosaurs, and 2 open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment

  15. Eggshell Porosity Provides Insight on Evolution of Nesting in Dinosaurs.

    Science.gov (United States)

    Tanaka, Kohei; Zelenitsky, Darla K; Therrien, François

    2015-01-01

    Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1) covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes), and 2) open nests, in which eggs are exposed in the nest and brooded (as in most birds). Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity) of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1) covered nests are likely the primitive condition for dinosaurs (and probably archosaurs), and 2) open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids) were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment. Open nests

  16. Clinical use of femoral artery hemostasis sticking after interventional procedure via femoral artery access

    International Nuclear Information System (INIS)

    Zhu Zhongsheng; Chen Shaoliang; Ye Fei; Zhang Junjie; Zhou Jie; Tian Nailiang; Lin Song; Liu Zhizhong; Xiao Pingxi; Qu Hong

    2010-01-01

    Objective: To observe the clinical effect of the use of femoral artery hemostasis sticking V+PAD after the interventional procedure via femoral artery access. Methods: By using random permutation list 80 patients, who decided to receive coronary angiography and percutaneous transluminal coronary angioplasty, were randomly selected. Of the 80 patients, hemostasis sticking V + PAD was employed in 40 patients with even numbers (trial group), only manual compression was adopted to stop bleeding in another 40 patients with odd numbers (control group). All the patients were informed about this trial and had to sign a consent letter. The pressure time, the treatment method of access site after hemostasis, the posture in bed, the immobilization time, the comfort degree of patients, the complications of access site prior to discharge, etc. were observed and the results were compared between two groups. Results: There was no significant difference between two groups as respect to age, gender ratios,activated clotting time (ACT) value and blood pressure. However, significantly difference in the compression time and bed rest time existed between the two groups. The compression time in trial group and control group was (7.9 ± 0.5) min and (19.8 ± 5.1) min respectively (P<0.01), while the bed rest time in trial group and control group was (6.1 ± 5.0) hours and (23.9 ± 0.2) hours respectively (P<0.01). All patients in trial group was supine in bed with the head side of the bed raised at 30 degree immediately after the procedure, and the head side of the bed was further raised to 90 degree one hour later. The puncture site was bandaged with conventional compression and immobilization was not employed. Patients could lie in bed with free posture and the patient's comfort degree was greatly improved. During hospitalization no complications related to puncture site occurred in all patients except one obese woman in trial group who developed pseudoaneurysm. Conclusion: Femoral

  17. Nest Success and Cause-Specific Nest Failure of Grassland Passerines Breeding in Prairie Grazed by Livestock

    Science.gov (United States)

    This manuscript describes two years of field research on ground-nesting songbird species at Zumwalt Prairie Reserve, northeastern Oregon, USA. Cattle-grazing has long been suspected in declines of ground-nesting songbirds in grazed grassland, primarily due to increased trampling...

  18. Fiber Tracking Cylinder Nesting

    International Nuclear Information System (INIS)

    Stredde, H.

    1999-01-01

    The fiber tracker consists of 8 concentric carbon fiber cylinders of varying diameters, from 399mm to 1032.2mm and two different lengths. 1.66 and 2.52 meters. Each completed cylinder is covered over the entire o.d. with scintillating fiber ribbons with a connector on each ribbon. These ribbons are axial (parallel to the beam line) at one end and stereo (at 3 deg. to the beam line) at the other. The ribbon connectors have dowel pins which are used to match with the connectors on the wave guide ribbons. These dowel pins are also used during the nesting operation, locating and positioning measurements. The nesting operation is the insertion of one cylinder into another, aligning them with one another and fastening them together into a homogeneous assembly. For ease of assembly. the nesting operation is accomplished working from largest diameter to smallest. Although the completed assembly of all 8 cylinders glued and bolted together is very stiff. individual cylinders are relatively flexible. Therefore. during this operation, No.8 must be supported in a manner which maintains its integrity and yet allows the insertion of No.7. This is accomplished by essentially building a set of dummy end plates which replicate a No.9 cylinder. These end plates are mounted on a wheeled cart that becomes the nesting cart. Provisions for a protective cover fastened to these rings has been made and will be incorporated in finished product. These covers can be easily removed for access to No.8 and/or the connection of No.8 to No.9. Another wheeled cart, transfer cart, is used to push a completed cylinder into the cylinder(s) already mounted in the nesting cart.

  19. Robust output-feedback control to eliminate stick-slip oscillations in drill-string systems

    NARCIS (Netherlands)

    Vromen, T.G.M.; Dai, C.H.; van de Wouw, N.; Oomen, T.A.E.; Astrid, P.; Nijmeijer, H.

    2015-01-01

    The aim of this paper is to design a robust output-feedback controller to eliminate torsional stick-slip vibrations. A multi-modal model of the torsional dynamics with a nonlinear bit-rock interaction model is used. The controller design is based on skewed-μ DK-iteration and the stability of the

  20. Predaceous ants, beach replenishment, and nest placement by sea turtles.

    Science.gov (United States)

    Wetterer, James K; Wood, Lawrence D; Johnson, Chris; Krahe, Holly; Fitchett, Stephanie

    2007-10-01

    Ants known for attacking and killing hatchling birds and reptiles include the red imported fire ant (Solenopsis invicta Buren), tropical fire ant [Solenopsis geminata (Fabr.)], and little fire ant [Wasmannia auropunctata (Roger)]. We tested whether sea turtle nest placement influenced exposure to predaceous ants. In 2000 and 2001, we surveyed ants along a Florida beach where green turtles (Chelonia mydas L.), leatherbacks (Dermochelys coriacea Vandelli), and loggerheads (Caretta caretta L.) nest. Part of the beach was artificially replenished between our two surveys. As a result, mean beach width experienced by nesting turtles differed greatly between the two nesting seasons. We surveyed 1,548 sea turtle nests (2000: 909 nests; 2001: 639 nests) and found 22 ant species. S. invicta was by far the most common species (on 431 nests); S. geminata and W. auropunctata were uncommon (on 3 and 16 nests, respectively). In 2000, 62.5% of nests had ants present (35.9% with S. invicta), but in 2001, only 30.5% of the nests had ants present (16.4% with S. invicta). Turtle nests closer to dune vegetation had significantly greater exposure to ants. Differences in ant presence on turtle nests between years and among turtle species were closely related to differences in nest placement relative to dune vegetation. Beach replenishment significantly lowered exposure of nests to ants because on the wider beaches turtles nested farther from the dune vegetation. Selective pressures on nesting sea turtles are altered both by the presence of predaceous ants and the practice of beach replenishment.

  1. Lesser prairie-chicken nest site selection, microclimate, and nest survival in association with vegetation response to a grassland restoration program

    Science.gov (United States)

    Boal, Clint W.; Grisham, Blake A.; Haukos, David A.; Zavaleta, Jennifer C.; Dixon, Charles

    2014-01-01

    Climate models predict that the region of the Great Plains Landscape Conservation Cooperative (GPLCC) will experience increased maximum and minimum temperatures, reduced frequency but greater intensity of precipitation events, and earlier springs. These climate changes along with different landscape management techniques may influence the persistence of the lesser prairie-chicken (Tympanuchus pallidicinctus), a candidate for protection under the Endangered Species Act and a priority species under the GPLCC, in positive or negative ways. The objectives of this study were to conduct (1) a literature review of lesser prairie-chicken nesting phenology and ecology, (2) an analysis of thermal aspects of lesser prairie-chicken nest microclimate data, and (3) an analysis of nest site selection, nest survival, and vegetation response to 10 years of tebuthiuron and/or grazing treatments. We found few reports in the literature containing useful data on the nesting phenology of lesser prairie-chickens; therefore, managers must rely on short-term observations and measurements of parameters that provide some predictive insight into climate impacts on nesting ecology. Our field studies showed that prairie-chickens on nests were able to maintain relatively consistent average nest temperature of 31 °C and nest humidities of 56.8 percent whereas average external temperatures (20.3–35.0 °C) and humidities (35.2–74.9 percent) varied widely throughout the 24 hour (hr) cycle. Grazing and herbicide treatments within our experimental areas were designed to be less intensive than in common practice. We determined nest locations by radio-tagging hen lesser prairie-chickens captured at leks, which are display grounds at which male lesser prairie-chickens aggregate and attempt to attract a female for mating. Because nest locations selected by hen lesser prairie-chicken are strongly associated with the lek at which they were captured, we assessed nesting habitat use on the basis of hens

  2. Waffle production: influence of batter ingredients on sticking of fresh egg waffles at baking plates-Part I: effect of starch and sugar components.

    Science.gov (United States)

    Huber, Regina; Schoenlechner, Regine

    2017-05-01

    Fresh egg waffles are a sweet convenience product typically baked from eggs, water, sugar, flour, fat, leavening agents, emulsifiers, preservatives, and flavors. In industrial production, waffles are baked continuously in high amounts of up to 200 kg raw material per hour. Therefore, it is important that the waffles do not stick onto the baking plates, which can cause significant product loss and increased costs due to interruption of the baking process, required cleaning procedures, and restarting of the energy-consuming start-up phase. Sticking of waffles is greatly influenced not only by baking plate material, release agent, baking temperature, and time, but also by the batter ingredients. In this study, effects of different starches and sugar components were investigated. Within the selected starches, potato starch demonstrated the highest effects on increasing waffle stability and releasing properties compared to wheat and lupine flour (less than 7% sticking waffles). Rice flour performed worst, with almost 50% of sticking waffles. Most of these waffles were broken during take-off, due to their crumbly texture. Within the sugar components, glycerine was better suitable than sorbitol and crystal sugar was superior compared to powdered sugar. They required less take-off force. It could be demonstrated that waffles with increased stability and texture were those that showed the least number of sticking waffles, thus the main aim of batter ingredients was to improve waffle quality. Waffle quality was influenced by batter parameters, significant correlations could be found, for example, a positive correlation between pH- and L-value, negative correlations between pH- and a-value, or density and aw-value. This resulted in significant correlations with take-off-force, which was correlated with L*- and b*-value (negative) and positive to a*-value. Sticking behavior was strongly associated with b*-value (positive) and to a*-value (negative).

  3. Stick-slip substructure in rapid tape peeling

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2010-10-15

    The peeling of adhesive tape is known to proceed with a stick-slip mechanism and produces a characteristic ripping sound. The peeling also produces light and when peeled in a vacuum, even X-rays have been observed, whose emissions are correlated with the slip events. Here we present direct imaging of the detachment zone when Scotch tape is peeled off at high speed from a solid surface, revealing a highly regular substructure, during the slip phase. The typical 4-mm-long slip region has a regular substructure of transverse 220 μm wide slip bands, which fracture sideways at speeds over 300 m/s. The fracture tip emits waves into the detached section of the tape at ∼100 m/s, which promotes the sound, so characteristic of this phenomenon.

  4. Stick-slip substructure in rapid tape peeling

    KAUST Repository

    Thoroddsen, Sigurdur T; Nguyen, H. D.; Takehara, K.; Etoh, T. G.

    2010-01-01

    The peeling of adhesive tape is known to proceed with a stick-slip mechanism and produces a characteristic ripping sound. The peeling also produces light and when peeled in a vacuum, even X-rays have been observed, whose emissions are correlated with the slip events. Here we present direct imaging of the detachment zone when Scotch tape is peeled off at high speed from a solid surface, revealing a highly regular substructure, during the slip phase. The typical 4-mm-long slip region has a regular substructure of transverse 220 μm wide slip bands, which fracture sideways at speeds over 300 m/s. The fracture tip emits waves into the detached section of the tape at ∼100 m/s, which promotes the sound, so characteristic of this phenomenon.

  5. Some remarks on sticking fraction calculations in muon-catalyzed deuterium-tritium fusion

    International Nuclear Information System (INIS)

    Biedenharn, L.C.; Ciftci, A.K.

    1992-01-01

    The sticking coefficient in muon catalyzed dt fusion is an important parameter affecting feasibility for practical applications. This paper discusses a procedure, developed for an accurate calculation of this parameter, and show that a well-defined limit produces precisely the often-criticized heuristic sudden approximation. Why this should be is discussed in some detail from a very different, possibly surprising, point of view

  6. Antioxidant capacity of chewing stick miswak Salvadora persica.

    Science.gov (United States)

    Mohamed, Saleh A; Khan, Jalaluddin A

    2013-02-21

    Chewing stick (miswak Salvadora persica L.) is an effective tool for oral hygiene. It possessed various biological properties including significant antibacterial and anti-fungal effects. In the present study, we evaluated the antioxidant compounds in miswak. Miswak root was extracted with 80% methanol. Methanol extract as antioxidant was evaluated by using DPPH, ABTS and phosphomolybdenum complex assays and analysis by GC-MS. Peroxidase, catalase and polyphenoloxidase assays were performed for crude extract of miswak root. The methanol extract of miswak contained the highest amount of crude extract among the various solvent extracts. The methanol extract showed a concentration dependent scavenging of DPPH and ABTS radicals with IC50 values 4.8 and 1.6 μg crude extract, respectively. The total antioxidant activities, based on the reduction of molybdenum (VI) to molybdenum (V), increased with increasing crude extract content. The correlation coefficients (R2) between total crude extract and DPPH, ABTS scavenging activities and the formation of phosphomolybdenum complex were 0.97, 0.99 and 0.95, respectively. The GC-MS analysis showed that the methanol extract doesn't contain phenolic and flavonoid compounds or under detected limit. After silylation of methanol extract, three compounds namely 2-furancarboxaldehyde-5-(hydroxymethyl), furan-2-carboxylic acid-3-methyl- trimethylsilyl ester and D-erythro-pentofuranose-2-deoxy-1,3,5-tris-O-(trimethylsilyl) were identified by GC-MS analysis. These furan derivatives as they contain hydroxyl groups could be possessed antioxidant activities. The antioxidant enzymes were also detected in the miswak extract with high level of peroxidase and low level of catalase and polyphenoloxidase. The synergistic actions of antioxidant compounds and antioxidant enzymes make miswak is a good chewing stick for oral hygiene and food purposes.

  7. Nest suitability, fine-scale population structure and male-mediated dispersal of a solitary ground nesting bee in an urban landscape.

    Science.gov (United States)

    López-Uribe, Margarita M; Morreale, Stephen J; Santiago, Christine K; Danforth, Bryan N

    2015-01-01

    Bees are the primary pollinators of flowering plants in almost all ecosystems. Worldwide declines in bee populations have raised awareness about the importance of their ecological role in maintaining ecosystem functioning. The naturally strong philopatric behavior that some bee species show can be detrimental to population viability through increased probability of inbreeding. Furthermore, bee populations found in human-altered landscapes, such as urban areas, can experience lower levels of gene flow and effective population sizes, increasing potential for inbreeding depression in wild bee populations. In this study, we investigated the fine-scale population structure of the solitary bee Colletes inaequalis in an urbanized landscape. First, we developed a predictive spatial model to detect suitable nesting habitat for this ground nesting bee and to inform our field search for nests. We genotyped 18 microsatellites in 548 female individuals collected from nest aggregations throughout the study area. Genetic relatedness estimates revealed that genetic similarity among individuals was slightly greater within nest aggregations than among randomly chosen individuals. However, genetic structure among nest aggregations was low (Nei's GST = 0.011). Reconstruction of parental genotypes revealed greater genetic relatedness among females than among males within nest aggregations, suggesting male-mediated dispersal as a potentially important mechanism of population connectivity and inbreeding avoidance. Size of nesting patch was positively correlated with effective population size, but not with other estimators of genetic diversity. We detected a positive trend between geographic distance and genetic differentiation between nest aggregations. Our landscape genetic models suggest that increased urbanization is likely associated with higher levels of inbreeding. Overall, these findings emphasize the importance of density and distribution of suitable nesting patches for enhancing

  8. Nest suitability, fine-scale population structure and male-mediated dispersal of a solitary ground nesting bee in an urban landscape.

    Directory of Open Access Journals (Sweden)

    Margarita M López-Uribe

    Full Text Available Bees are the primary pollinators of flowering plants in almost all ecosystems. Worldwide declines in bee populations have raised awareness about the importance of their ecological role in maintaining ecosystem functioning. The naturally strong philopatric behavior that some bee species show can be detrimental to population viability through increased probability of inbreeding. Furthermore, bee populations found in human-altered landscapes, such as urban areas, can experience lower levels of gene flow and effective population sizes, increasing potential for inbreeding depression in wild bee populations. In this study, we investigated the fine-scale population structure of the solitary bee Colletes inaequalis in an urbanized landscape. First, we developed a predictive spatial model to detect suitable nesting habitat for this ground nesting bee and to inform our field search for nests. We genotyped 18 microsatellites in 548 female individuals collected from nest aggregations throughout the study area. Genetic relatedness estimates revealed that genetic similarity among individuals was slightly greater within nest aggregations than among randomly chosen individuals. However, genetic structure among nest aggregations was low (Nei's GST = 0.011. Reconstruction of parental genotypes revealed greater genetic relatedness among females than among males within nest aggregations, suggesting male-mediated dispersal as a potentially important mechanism of population connectivity and inbreeding avoidance. Size of nesting patch was positively correlated with effective population size, but not with other estimators of genetic diversity. We detected a positive trend between geographic distance and genetic differentiation between nest aggregations. Our landscape genetic models suggest that increased urbanization is likely associated with higher levels of inbreeding. Overall, these findings emphasize the importance of density and distribution of suitable nesting

  9. Creep and stick-slip in subglacial granular beds forced by variations in water pressure

    DEFF Research Database (Denmark)

    Damsgaard, Anders; Egholm, David Lundbek; Beem, Lucas H.

    of these sediment remains poorly understood. Measurements and laboratory experiments provide important constraints, but existing models have not been able to explain the internal processes driving transitions from stability to stick-slip within the sediment. In this presentation we use a coupled numerical model...

  10. Importance of structural stability to success of mourning dove nests

    Science.gov (United States)

    Coon, R.A.; Nichols, J.D.; Percival, H.F.

    1981-01-01

    Studies of nest-site selection and nesting habitats often involve a "characterization" of nests and of habitats in which nests are found. Our objective in the present work is to identify nest-site characteristics that are associated with variation in components of Mourning Dove (Zenaida macroura) fitness (e.g. the probability of a nest succeeding), as opposed to simply "characterizing" dove nest sites. If certain nest- site characteristics affect the probability that a nest will succeed, then we suspect that these characteristics will be associated with either concealment (the probability of detection by certain predators) or structural stability (the probability of eggs or entire nests falling to the ground as a result of wind, rain storms, parental activity, etc.). Although other workers agree that structural stability is an important determinant of Mourning Dove nesting success (e.g. McClure 1944: 384; Woolfenden and Rohwer 1969: 59), we are aware of no actual tests of this hypothesis.

  11. The effects of large beach debris on nesting sea turtles

    Science.gov (United States)

    Fujisaki, Ikuko; Lamont, Margaret M.

    2016-01-01

    A field experiment was conducted to understand the effects of large beach debris on sea turtle nesting behavior as well as the effectiveness of large debris removal for habitat restoration. Large natural and anthropogenic debris were removed from one of three sections of a sea turtle nesting beach and distributions of nests and false crawls (non-nesting crawls) in pre- (2011–2012) and post- (2013–2014) removal years in the three sections were compared. The number of nests increased 200% and the number of false crawls increased 55% in the experimental section, whereas a corresponding increase in number of nests and false crawls was not observed in the other two sections where debris removal was not conducted. The proportion of nest and false crawl abundance in all three beach sections was significantly different between pre- and post-removal years. The nesting success, the percent of successful nests in total nesting attempts (number of nests + false crawls), also increased from 24% to 38%; however the magnitude of the increase was comparably small because both the number of nests and false crawls increased, and thus the proportion of the nesting success in the experimental beach in pre- and post-removal years was not significantly different. The substantial increase in sea turtle nesting activities after the removal of large debris indicates that large debris may have an adverse impact on sea turtle nesting behavior. Removal of large debris could be an effective restoration strategy to improve sea turtle nesting.

  12. Comprehensive Comparison between Empty Nest and Non-Empty Nest Elderly: A Cross-Sectional Study among Rural Populations in Northeast China

    Directory of Open Access Journals (Sweden)

    Ye Chang

    2016-08-01

    Full Text Available This study aimed to comprehensively compare the general characteristics, lifestyles, serum parameters, ultrasonic cardiogram (UCG parameters, depression, quality of life, and various comorbidities between empty nest and non-empty nest elderly among rural populations in northeast China. This analysis was based on our previous study which was conducted from January 2012 to August 2013, using a multistage, stratified, random cluster sampling scheme. The final analyzed sample consisted of 3208 participants aged no less than 60 years, which was further classified into three groups: non-empty nest group, empty nest group (living as a couple, and empty nest group (living alone. More than half of the participants were empty nest elderly (60.5%. There were no significant statistical differences for serum parameters, UCG parameters, lifestyles, dietary pattern, and scores of Patient Health Questionnaire-9 (PHQ-9 and World Health Organization Quality of Life questionnaire, abbreviated version (WHOQOL-BREF among the three groups. Empty nest elderly showed no more risk for comorbidities such as general obesity, abdominal obesity, hyperuricemia, hyperhomocysteinemia, diabetes, dyslipidemia, left atrial enlargement (LAE, and stroke. Our study indicated that empty nest elderly showed no more risk for depression, low quality of life and comorbidities such as general obesity, abdominal obesity, hyperuricemia, hyperhomocysteinemia, diabetes, dyslipidemia, LAE, and stroke among rural populations in northeast China.

  13. Effect of anisotropy on the sticking in muon-catalyzed fusion determined by the x-ray method

    International Nuclear Information System (INIS)

    Cohen, J.S.; Padial, N.T.

    1989-01-01

    The initial sticking in the 2p/sub m/ states of muonic helium in muon-catalyzed fusion (μCF) and the subsequent collisional excitation to these states are shown to have nonstatistical dependences on m that result in spatial anisotropy of the emitted x rays. This anisotropy, I(0 0 )/I(90 0 ), is found to be 0.71 for d-d μCF and 1.12 for d-t μCF in liquid targets, where the angle is between the coincidentally detected x ray and neutron. The effect is predicted to increase the actual Kα x-ray yield and corresponding sticking observed in a recent d-t μCF experiment by 4%. The Doppler broadening of the radiation observed at different angles is also examined

  14. Habitat and nesting biology of Mountain Plovers in Wyoming

    Science.gov (United States)

    Plumb, R.E.; Anderson, S.H.; Knopf, F.L.

    2005-01-01

    Although previous research has considered habitat associations and breeding biology of Mountain Plovers in Wyoming at discrete sites, no study has considered these attributes at a statewide scale. We located 55 Mountain Plover nests in 6 counties across Wyoming during 2002 and 2003. Nests occurred in 2 general habitat types: grassland and desert-shrub. Mean estimated hatch date was 26 June (n = 31) in 2002 and 21 June (n = 24) in 2003. Mean hatch date was not related to latitude or elevation. Hatch success of nests was inferred in 2003 by the presence of eggshell fragments in the nest scrape. Eggs in 14 of 22 (64%) known-fate nests hatched. All grassland sites and 90% of desert sites were host to ungulate grazers, although prairie dogs were absent at 64% of nest sites. Nest plots had less grass coverage and reduced grass height compared with random plots. More than 50% of nests occurred on elevated plateaus. The Mountain Plover's tendency to nest on arid, elevated plateaus further substantiates claims that the bird is also a disturbed-prairie species.

  15. Superposition Enhanced Nested Sampling

    Directory of Open Access Journals (Sweden)

    Stefano Martiniani

    2014-08-01

    Full Text Available The theoretical analysis of many problems in physics, astronomy, and applied mathematics requires an efficient numerical exploration of multimodal parameter spaces that exhibit broken ergodicity. Monte Carlo methods are widely used to deal with these classes of problems, but such simulations suffer from a ubiquitous sampling problem: The probability of sampling a particular state is proportional to its entropic weight. Devising an algorithm capable of sampling efficiently the full phase space is a long-standing problem. Here, we report a new hybrid method for the exploration of multimodal parameter spaces exhibiting broken ergodicity. Superposition enhanced nested sampling combines the strengths of global optimization with the unbiased or athermal sampling of nested sampling, greatly enhancing its efficiency with no additional parameters. We report extensive tests of this new approach for atomic clusters that are known to have energy landscapes for which conventional sampling schemes suffer from broken ergodicity. We also introduce a novel parallelization algorithm for nested sampling.

  16. Using survival analysis of artificial and Real Brewer's sparrow (Spizella breweri breweri) nests to model site level and nest site factors associated with nest success in the South Okanagan region of Canada

    Science.gov (United States)

    Pam Krannitz Kym Welstead

    2005-01-01

    Predation is the predominant cause of nest failure for the Brewer's Sparrow (Spizella breweri breweri), a provincially red-listed shrub-steppe species that has experienced significant declines throughout most of its range. We monitored Brewer’s Sparrow nests and conducted an artificial nest experiment, in the South Okanagan Valley,...

  17. Hurricane disturbance benefits nesting American Oystercatchers (Haematopus palliatus)

    Science.gov (United States)

    Simons, Theodore R.; Schulte, Shiloh A.

    2016-01-01

    Coastal ecosystems are under increasing pressure from human activity, introduced species, sea level rise, and storm activity. Hurricanes are a powerful destructive force, but can also renew coastal habitats. In 2003, Hurricane Isabel altered the barrier islands of North Carolina, flattening dunes and creating sand flats. American Oystercatchers (Haematopus palliatus) are large shorebirds that inhabit the coastal zone throughout the year. Alternative survival models were evaluated for 699 American Oystercatcher nests on North Core Banks and South Core Banks, North Carolina, USA, from 1999–2007. Nest survival on North Core Banks increased from 0.170 (SE = 0.002) to 0.772 (SE = 0.090) after the hurricane, with a carry-over effect lasting 2 years. A simple year effects model described nest survival on South Core Banks. Habitat had no effect on survival except when the overall rate of nest survival was at intermediate levels (0.300–0.600), when nests on open flats survived at a higher rate (0.600; SE = 0.112) than nests in dune habitat (0.243; SE = 0.094). Predator activity declined on North Core Banks after the hurricane and corresponded with an increase in nest survival. Periodic years with elevated nest survival may offset low annual productivity and contribute to the stability of American Oystercatcher populations.

  18. Canada goose nest survival at rural wetlands in north-central Iowa

    Science.gov (United States)

    Ness, Brenna N.; Klaver, Robert W.

    2016-01-01

    The last comprehensive nest survival study of the breeding giant Canada goose (Branta canadensis maxima) population in Iowa, USA, was conducted >30 years ago during a period of population recovery, during which available nesting habitat consisted primarily of artificial nest structures. Currently, Iowa's resident goose population is stable and nests in a variety of habitats. We analyzed the effects of available habitat on nest survival and how nest survival rates compared with those of the expanding goose population studied previously to better understand how to maintain a sustainable Canada goose population in Iowa. We documented Canada goose nest survival at rural wetland sites in north-central Iowa. We monitored 121 nests in 2013 and 149 nests in 2014 at 5 Wildlife Management Areas (WMAs) with various nesting habitats, including islands, muskrat (Ondatra zibethicus) houses, and elevated nest structures. We estimated daily nest-survival rate using the nest survival model in Program MARK. Survival was influenced by year, site, stage, presence of a camera, nest age, and an interaction between nest age and stage. Nest success rates for the 28-day incubation period by site and year combination ranged from 0.10 to 0.84. Nest survival was greatest at sites with nest structures (β = 17.34). Nest survival was negatively affected by lowered water levels at Rice Lake WMA (2013 β = −0.77, nest age β = −0.07). Timing of water-level drawdowns for shallow lake restorations may influence nest survival rates.

  19. Nest sharing under semi-natural conditions in laying hens

    DEFF Research Database (Denmark)

    Riber, Anja Brinch

    2012-01-01

    problems to laying hens, and egg production may also be negatively affected. Understanding what causes this difference in nest location selection may provide solutions to the problems associated with simultaneous nest sharing. The aims were to investigate whether a commercial strain of laying hens normally...... daily of each nest with regard to number of eggs, position, and materials used. On five mornings nesting behaviour was observed. Nest sharing occurred on all but the first 5 days of egg-laying. The majority of hens (n = 14) chose to visit an occupied nest at least once, but no hens exclusively used...

  20. Caching behaviour by red squirrels may contribute to food conditioning of grizzly bears

    Directory of Open Access Journals (Sweden)

    Julia Elizabeth Put

    2017-08-01

    Full Text Available We describe an interspecific relationship wherein grizzly bears (Ursus arctos horribilis appear to seek out and consume agricultural seeds concentrated in the middens of red squirrels (Tamiasciurus hudsonicus, which had collected and cached spilled grain from a railway. We studied this interaction by estimating squirrel density, midden density and contents, and bear activity along paired transects that were near (within 50 m or far (200 m from the railway. Relative to far ones, near transects had 2.4 times more squirrel sightings, but similar numbers of squirrel middens. Among 15 middens in which agricultural products were found, 14 were near the rail and 4 subsequently exhibited evidence of bear digging. Remote cameras confirmed the presence of squirrels on the rail and bears excavating middens. We speculate that obtaining grain from squirrel middens encourages bears to seek grain on the railway, potentially contributing to their rising risk of collisions with trains.

  1. Emperor penguins nesting on Inaccessible Island

    Science.gov (United States)

    Jonkel, G.M.; Llano, G.A.

    1975-01-01

    Emperor penguins were observed nesting on Inaccessible I. during the 1973 winter. This is the southernmost nesting of emperor penguins thus far recorded; it also could be the first record of emperors attempting to start a new rookery. This site, however, may have been used by emperors in the past. The closest reported nesting of these penguins to Inaccessible I. is on the Ross Ice Shelf east of Cape Crozier. With the exception of the Inaccessible I. record, there is little evidence that emperor penguins breed in McMurdo Sound proper.

  2. Risk from cattle trampling to nests of an endangered passerine evaluated using artificial nest experiments and simulations

    Directory of Open Access Journals (Sweden)

    Brian W. Rolek

    2016-06-01

    Full Text Available Grasslands are often grazed by cattle and many grassland birds nest on the ground, potentially exposing nests to trampling. We tested for trampling risk introduced by cattle to nests of endangered Florida Grasshopper Sparrows (Ammodramus savannarum floridanus using experimentally paired grids of artificial nests (i.e., clay targets similar in size to nests of Florida Grasshopper Sparrows and counted the number of clay targets that were broken in paired grazed and ungrazed enclosures. Clay targets in grazed grids were trampled 3.9% more often than their respective ungrazed grids, and measurements of cattle presence or density were correlated with the number of broken clay targets, suggesting that excluding cattle during breeding is an important management recommendation for the Florida Grasshopper Sparrow. Trampling rates within grazed enclosures were spatially homogeneous with respect to cattle infrastructure such as supplemental feeding troughs and fences, and forests and stocking density were poor predictors of trampling rates when excluding ungrazed grids. We used population viability analysis to compare quasi-extinction rates, intrinsic growth rates, and median abundance in grazed and ungrazed Florida Grasshopper Sparrow aggregations to further understand the biological significance of management aimed at reducing trampling rates during the breeding season. Simulations indicated that trampling from grazing increased quasi-extinction rates by 41% while reducing intrinsic growth rates by 0.048, and reducing median abundance by an average of 214 singing males after 50 years. Management should avoid grazing enclosures occupied by Florida Grasshopper Sparrows during the nesting season to minimize trampling rates. Our methods that combine trampling experiments with population viability analysis provide a framework for testing effects from trampling on other grassland ground-nesting birds, and can directly inform conservation and management of the

  3. The reasons for the different nest shapes of Megapis bees

    Directory of Open Access Journals (Sweden)

    Woyke Jerzy

    2016-06-01

    Full Text Available Over a 37-year period, we observed 1011 active bee nests and abandoned combs of Apis dorsata and Apis laboriosa in Nepal, India, the Philippines, and Bhutan. This article focuses on the reasons for the different shapes of the nests. We discovered that differing ambient conditions were the reasons for the following three shapes of symmetrical nests: vertical semi-ellipse, semicircle, and the horizontal semi-ellipse. We noted that asymmetrical nests were constructed when there was lack of space to extend the comb equally in both external directions. An asymmetrical nest also appeared when remnants of a previous comb remained on one edge of the nest. Convex nests were constructed to avoid excess sun exposure. Concave nests appeared as a result of low temperatures during the night and part of the day (Nepal. An L-shape nest was constructed when there was lack of space available to extend the nest in a straight direction. The shape of the nests also determines the way the combs fall.

  4. Comparative evaluation of uniplex, nested, semi-nested, multiplex and nested multiplex PCR methods in the identification of microbial etiology of clinically suspected infectious endophthalmitis.

    Science.gov (United States)

    Bharathi, Madasamy Jayahar; Murugan, Nandagopal; Rameshkumar, Gunasekaran; Ramakrishnan, Rengappa; Venugopal Reddy, Yerahaia Chinna; Shivkumar, Chandrasekar; Ramesh, Srinivasan

    2013-05-01

    This study is aimed to determine the utility of various polymerase chain reaction (PCR) methods in vitreous fluids (VFs) for detecting the infectious genomes in the diagnosis of infectious endophthalmitis in terms of sensitivity and specificity. This prospective and consecutive analysis included a total of 66 VFs that were submitted for the microbiological evaluation, which were obtained from 66 clinically diagnosed endophthalmitis patients presented between November 2010 and October 2011 at the tertiary eye care referral centre in South India. Part of the collected VFs were subjected to cultures and smears, and the remaining parts were utilized for five PCR methods: uniplex, nested, semi-nested, multiplex and nested multiplex after extracting DNA, using universal eubacterial and Propionibacterium acnes species-specific primer sets targeting 16S rRNA gene in all bacteria and P. acnes, and panfungal primers, targeting 28S rRNA gene in all fungi. Of the 66 VFs, five (7.5%) showed positive results in smears, 16 (24%) in cultures and 43 (65%) showed positive results in PCRs. Among the 43 positively amplified VFs, 10 (15%) were positive for P. acnes genome, one for panfungal genome and 42 (62%) for eubacterial genome (including 10 P. acnes positives). Among 42 eubacterial-positive VFs, 36 were positive by both uniplex (first round) and multiplex (first round) PCRs, while nested (second round) and nested multiplex (second round) PCRs produced positive results in 42 and 41 VFs, respectively. Of the 43 PCR-positive specimens, 16 (37%) had positive growth (15 bacterial and one fungal) in culture. Of 50 culture-negative specimens, 27 (54%) were showed positive amplification, of which 10 were amplified for both P. acnes and eubacterial genomes and the remaining 17 were for eubacterial genome alone. Nested PCRs are superior than uniplex and multiplex PCR. PCRs proved to be a powerful tool in the diagnosis of endophthalmitis, especially for detecting uncultured microbes.

  5. Variation in clutch size in relation to nest size in birds.

    Science.gov (United States)

    Møller, Anders P; Adriaensen, Frank; Artemyev, Alexandr; Bańbura, Jerzy; Barba, Emilio; Biard, Clotilde; Blondel, Jacques; Bouslama, Zihad; Bouvier, Jean-Charles; Camprodon, Jordi; Cecere, Francesco; Charmantier, Anne; Charter, Motti; Cichoń, Mariusz; Cusimano, Camillo; Czeszczewik, Dorota; Demeyrier, Virginie; Doligez, Blandine; Doutrelant, Claire; Dubiec, Anna; Eens, Marcel; Eeva, Tapio; Faivre, Bruno; Ferns, Peter N; Forsman, Jukka T; García-Del-Rey, Eduardo; Goldshtein, Aya; Goodenough, Anne E; Gosler, Andrew G; Góźdź, Iga; Grégoire, Arnaud; Gustafsson, Lars; Hartley, Ian R; Heeb, Philipp; Hinsley, Shelley A; Isenmann, Paul; Jacob, Staffan; Järvinen, Antero; Juškaitis, Rimvydas; Korpimäki, Erkki; Krams, Indrikis; Laaksonen, Toni; Leclercq, Bernard; Lehikoinen, Esa; Loukola, Olli; Lundberg, Arne; Mainwaring, Mark C; Mänd, Raivo; Massa, Bruno; Mazgajski, Tomasz D; Merino, Santiago; Mitrus, Cezary; Mönkkönen, Mikko; Morales-Fernaz, Judith; Morin, Xavier; Nager, Ruedi G; Nilsson, Jan-Åke; Nilsson, Sven G; Norte, Ana C; Orell, Markku; Perret, Philippe; Pimentel, Carla S; Pinxten, Rianne; Priedniece, Ilze; Quidoz, Marie-Claude; Remeš, Vladimir; Richner, Heinz; Robles, Hugo; Rytkönen, Seppo; Senar, Juan Carlos; Seppänen, Janne T; da Silva, Luís P; Slagsvold, Tore; Solonen, Tapio; Sorace, Alberto; Stenning, Martyn J; Török, János; Tryjanowski, Piotr; van Noordwijk, Arie J; von Numers, Mikael; Walankiewicz, Wiesław; Lambrechts, Marcel M

    2014-09-01

    Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of egg-laying. Parent birds should be selected to choose nest sites and to build optimally sized nests, yet our current understanding of clutch size-nest size relationships is limited to small-scale studies performed over short time periods. Here, we quantified the relationship between clutch size and nest size, using an exhaustive database of 116 slope estimates based on 17,472 nests of 21 species of hole and non-hole-nesting birds. There was a significant, positive relationship between clutch size and the base area of the nest box or the nest, and this relationship did not differ significantly between open nesting and hole-nesting species. The slope of the relationship showed significant intraspecific and interspecific heterogeneity among four species of secondary hole-nesting species, but also among all 116 slope estimates. The estimated relationship between clutch size and nest box base area in study sites with more than a single size of nest box was not significantly different from the relationship using studies with only a single size of nest box. The slope of the relationship between clutch size and nest base area in different species of birds was significantly negatively related to minimum base area, and less so to maximum base area in a given study. These findings are consistent with the hypothesis that bird species have a general reaction norm reflecting the relationship between nest size and clutch size. Further, they suggest that scientists may influence the clutch size decisions of hole-nesting birds through the provisioning of nest boxes of varying sizes.

  6. Nest site selection by Hypsiboas faber(Anura, Hylidae in Southern Brazil

    Directory of Open Access Journals (Sweden)

    André L. Luza

    2015-12-01

    Full Text Available ABSTRACT Male gladiator frogs of Hypsiboas Wagler, 1830 build nests on available substrate surrounding ponds and streams where female spawn eggs during the breeding period. Although gladiator frogs seem to show plasticity in the way they construct their nests, there is no study reporting if these species present preferences about microhabitat conditions for nest-building (mainly under subtropical climate. Predation pressure and environmental conditions have been considered major processes shaping the great diversity of reproductive strategies performed by amphibians, but microhabitat conditions should explain where to build a nest as well as how nest looks. This study aimed to test nest site selection for nest-building by Hypsiboas faber(Wied-Neuwied, 1821, determining which factors are related to nest site selection and nest features. The survey was conducted at margins of two permanent ponds in Southern Brazil. Habitat factors were evaluated in 18 plots with nest and 18 plots in the surrounding without nest (control, describing vegetation structure and heterogeneity, and substrate characteristics. Water temperature was measured inside the nest and in its adjacency. Nest features assessed were area, depth and temperature. Habitat characteristics differed between plots with and without nest. Microhabitat selected for nest-building was characterized by great vegetation cover and height, as well as shallower water and lower cover of organic matter in suspension than in plots without nest. Differences between temperature inside nest and in its adjacency were not observed. No relationship between nest features and habitat descriptors was evidenced. Results revealed that Hypsiboas faber does not build nests anywhere. Males seem to prefer more protected habitats, probably avoiding predation, invasion of conspecific males and inclement weather. Lack of differences between temperature inside- and outside-nest suggest that nest do not improve this

  7. A change management approach to improving safety and preventing needle stick injuries.

    Science.gov (United States)

    Aziz, Ann-Marie

    2017-09-01

    Key drivers for preventing healthcare-associated infection (HCAI) include evidence-based practices and procedures that prevent infection. Among the current guidance for preventing HCAIs is evidence and mandatory requirements for reducing needle stick injuries (NSIs). This article highlights how John Kotter's model for change could help healthcare workers plan for successful and sustained deployment of needle safety devices (NSDs) and ultimately reduce the risk of a NSI.

  8. Miniature stick-packaging--an industrial technology for pre-storage and release of reagents in lab-on-a-chip systems.

    Science.gov (United States)

    van Oordt, Thomas; Barb, Yannick; Smetana, Jan; Zengerle, Roland; von Stetten, Felix

    2013-08-07

    Stick-packaging of goods in tubular-shaped composite-foil pouches has become a popular technology for food and drug packaging. We miniaturized stick-packaging for use in lab-on-a-chip (LOAC) systems to pre-store and on-demand release the liquid and dry reagents in a volume range of 80-500 μl. An integrated frangible seal enables the pressure-controlled release of reagents and simplifies the layout of LOAC systems, thereby making the package a functional microfluidic release unit. The frangible seal is adjusted to defined burst pressures ranging from 20 to 140 kPa. The applied ultrasonic welding process allows the packaging of temperature sensitive reagents. Stick-packs have been successfully tested applying recovery tests (where 99% (STDV = 1%) of 250 μl pre-stored liquid is released), long-term storage tests (where there is loss of only <0.5% for simulated 2 years) and air transport simulation tests. The developed technology enables the storage of a combination of liquid and dry reagents. It is a scalable technology suitable for rapid prototyping and low-cost mass production.

  9. Factors affecting nesting success in the Great-crested Grebe ...

    African Journals Online (AJOL)

    The overall nesting success was 70.4% (N = 209), with nest failure caused mainly by predation (65%) and flooding (23%). Breeding outcome was significantly and positively related to nest size, with bigger nests conferring better survival to eggs and young probably through affording better protection during spells of adverse ...

  10. Moiré superlattice-level stick-slip instability originated from geometrically corrugated graphene on a strongly interacting substrate

    Science.gov (United States)

    Shi, Ruoyu; Gao, Lei; Lu, Hongliang; Li, Qunyang; Ma, Tian-Bao; Guo, Hui; Du, Shixuan; Feng, Xi-Qiao; Zhang, Shuai; Liu, Yanmin; Cheng, Peng; Hu, Yuan-Zhong; Gao, Hong-Jun; Luo, Jianbin

    2017-06-01

    Two dimensional (2D) materials often exhibit novel properties due to various coupling effects with their supporting substrates. Here, using friction force microscopy (FFM), we report an unusual moiré superlattice-level stick-slip instability on monolayer graphene epitaxially grown on Ru(0 0 0 1) substrate. Instead of smooth friction modulation, a significant long-range stick-slip sawtooth modulation emerges with a period coinciding with the moiré superlattice structure, which is robust against high external loads and leads to an additional channel of energy dissipation. In contrast, the long-range stick-slip instability reduces to smooth friction modulation on graphene/Ir(1 1 1) substrate. The moiré superlattice-level slip instability could be attributed to the large sliding energy barrier, which arises from the morphological corrugation of graphene on Ru(0 0 0 1) surface as indicated by density functional theory (DFT) calculations. The locally steep humps acting as obstacles opposing the tip sliding, originates from the strong interfacial electronic interaction between graphene and Ru(0 0 0 1). This study opens an avenue for modulating friction by tuning the interfacial atomic interaction between 2D materials and their substrates.

  11. Nesting ecology and nest success of the Blue Grosbeak along two rivers in New Mexico

    Science.gov (United States)

    Jean-Luc E. Cartron; Deborah M. Finch; David L. Hawksworth; Scott H. Stoleson

    2013-01-01

    From 1997 through 2008, we studied the nesting habits and nest success of the Blue Grosbeak (Passerina cerulean) along the middle Gila River (1997-2001) and the middle Rio Grande (2000-2008) in New Mexico. A riparian forest of cottonwoods grows along both rivers. but the forest along the Rio Grande is a much more intensively managed ecosystem, with an understory...

  12. Facultative nest patch shifts in response to nest predation risk in the Brewer's sparrow: a "win-stay, lose-switch" strategy?

    Science.gov (United States)

    Anna D. Chalfoun; Thomas E. Martin

    2010-01-01

    Facultative shifts in nesting habitat selection in response to perceived predation risk may allow animals to increase the survival probability of sessile offspring. Previous studies on this behavioral strategy have primarily focused on single attributes, such as the distance moved or changes in nesting substrate. However, nest site choice often encompasses multiple...

  13. Language Nests and Language Acquisition: An Empirical Analysis

    Science.gov (United States)

    Okura, Eve K.

    2017-01-01

    This dissertation presents the findings from interviews conducted with language nest workers, teachers, language nest coordinators, administrators of language revitalization programs, principals and directors of language immersion schools that work in close proximity with language nests, and linguists involved in language revitalization efforts.…

  14. Nest mortality of sagebrush songbirds due to a severe hailstorm

    Science.gov (United States)

    Hightower, Jessica N.; Carlisle, Jason D.; Chalfoun, Anna D.

    2018-01-01

    Demographic assessments of nesting birds typically focus on failures due to nest predation or brood parasitism. Extreme weather events such as hailstorms, however, can also destroy eggs and injure or kill juvenile and adult birds at the nest. We documented the effects of a severe hailstorm on 3 species of sagebrush-associated songbirds: Sage Thrasher (Oreoscoptes montanus), Brewer's Sparrow (Spizella breweri), and Vesper Sparrow (Pooecetes gramineus), nesting at eight 24 ha study plots in central Wyoming, USA. Across all plots, 17% of 128 nests failed due to the hailstorm; however, all failed nests were located at a subset of study plots (n = 3) where the hailstorm was most intense, and 45% of all nests failures on those plots were due to hail. Mortality rates varied by species, nest architecture, and nest placement. Nests with more robust architecture and those sited more deeply under the shrub canopy were more likely to survive the hailstorm, suggesting that natural history traits may modulate mortality risk due to hailstorms. While sporadic in nature, hailstorms may represent a significant source of nest failure to songbirds in certain locations, especially with increasing storm frequency and severity forecasted in some regions with ongoing climate change.

  15. Determinants of abundance and effects of blood-sucking flying insects in the nest of a hole-nesting bird.

    Science.gov (United States)

    Tomás, Gustavo; Merino, Santiago; Martínez-de la Puente, Josué; Moreno, Juan; Morales, Judith; Lobato, Elisa

    2008-05-01

    Compared to non-flying nest-dwelling ectoparasites, the biology of most species of flying ectoparasites and its potential impact on avian hosts is poorly known and rarely, if ever, reported. In this study we explore for the first time the factors that may affect biting midge (Diptera: Ceratopogonidae) and black fly (Diptera: Simuliidae) abundances in the nest cavity of a bird, the hole-nesting blue tit Cyanistes caeruleus, and report their effects on adults and nestlings during reproduction. The abundance of biting midges was positively associated with nest mass, parental provisioning effort and abundance of blowflies and black flies, while negatively associated with nestling condition. Furthermore, a medication treatment to reduce blood parasitaemias in adult birds revealed that biting midges were more abundant in nests of females whose blood parasitaemias were experimentally reduced. This finding would be in accordance with these insect vectors attacking preferentially uninfected or less infected hosts to increase their own survival. The abundance of black flies in the population was lower than that of biting midges and increased in nests with later hatching dates. No significant effect of black fly abundance on adult or nestling condition was detected. Blood-sucking flying insects may impose specific, particular selection pressures on their hosts and more research is needed to better understand these host-parasite associations.

  16. Nesting behavior of Palila, as assessed from video recordings

    Science.gov (United States)

    Laut, M.E.; Banko, P.C.; Gray, E.M.

    2003-01-01

    We quantified nesting behavior of Palila (Loxiodes bailleui), an endangered Hawaiian honeycreeper, by recording at nests during three breeding seasons using a black-and-white video camera connected to a Videocassette recorder. A total of seven nests was observed. We measured the following factors for daylight hours: percentage of time the female was on the nest (attendance), length of attendance bouts by the female, length of nest recesses, and adult provisioning rates. Comparisons were made between three stages of the 40-day nesting cycle: incubation (day 1-day 16), early nestling stage (day 17-day 30 [i.e., nestlings ??? 14 days old]), and late nestling stage (day 31-day 40 [i.e., nestlings > 14 days old]). Of seven nests observed, four fledged at least one nestling and three failed. One of these failed nests was filmed being depredated by a feral cat (Felis catus). Female nest attendance was near 82% during the incubation stage and decreased to 21% as nestlings aged. We did not detect a difference in attendance bout length between stages of the nesting cycle. Mean length of nest recesses increased from 4.5 min during the incubation stage to over 45 min during the late nestling stage. Mean number of nest recesses per hour ranged from 1.6 to 2.0. Food was delivered to nestlings by adults an average of 1.8 times per hour for the early nestling stage and 1.5 times per hour during the late nestling stage and did not change over time. Characterization of parental behavior by video had similarities to but also key differences from findings taken from blind observations. Results from this study will facilitate greater understanding of Palila reproductive strategies.

  17. A review of the nest protection hypothesis: does inclusion of fresh green plant material in birds' nests reduce parasite infestation?

    Science.gov (United States)

    Scott-Baumann, James F; Morgan, Eric R

    2015-07-01

    The use of aromatic plants and their essential oils for ectoparasite treatment is a field of growing interest. Several species of birds regularly introduce aromatic herbs into their nests putatively to reduce parasites. The behaviour is most often seen in cavity nesting birds and after nest building has finished. The plants are included in a non-structural manner and are often strongly aromatic. Various different hypotheses have been proposed regarding the function of this behaviour; from the plants altering some non-living factor in the nest (crypsis, water loss and insulation hypotheses) to them being involved in mate selection (mate hypothesis) or even having a beneficial effect, direct or indirect, on chicks (drug or nest protection hypothesis, NPH). Many studies have been carried out over the years observing and experimentally testing these hypotheses. This review focuses on studies involving the most popular of these hypotheses, the NPH: that plants decrease nest parasites or pathogens, thereby conveying positive effects to the chicks, allowing the behaviour to evolve. Studies providing observational evidence towards this hypothesis and those experimentally testing it are discussed.

  18. Effectiveness of nest site restoration for the endangered northern map turtle : report 2 : use of artificial nesting sites and wildlife exclusion fences to enhance nesting success : research summary.

    Science.gov (United States)

    2016-10-01

    The Northern Map Turtle, is a state Endangered Species, found only in the : lower Susquehanna River in Maryland. The only area where nests of this : species are not heavily impacted by predators is in the town of Port Deposit. : However, turtles nest...

  19. Effects of intraguild predators on nest-site selection by prey.

    Science.gov (United States)

    Huang, Wen-San; Pike, David A

    2012-01-01

    Nest-site selection involves tradeoffs between the risk of predation (on females and/or nests) and nest-site quality (microenvironment), and consequently suitable nesting sites are often in limited supply. Interactions with "classical" predators (e.g., those not competing for shared resources) can strongly influence nest-site selection, but whether intraguild predation also influences this behavior is unknown. We tested whether risk of predation from an intraguild predator [the diurnal scincid lizard Eutropis (Mabuya) longicaudata] influences nest-site selection by its prey (the nocturnal gecko Gekko hokouensis) on Orchid Island, Taiwan. These two species putatively compete for shared resources, including invertebrate prey and nesting microhabitat, but the larger E. longicaudata also predates G. hokouensis (but not its hard-shelled eggs). Both species nested within a concrete wall containing a series of drainage holes that have either one ("closed-in") or two openings ("open"). In allopatry, E. longicaudata preferred to nest within holes that were plugged by debris (thereby protecting eggs from water intrusion), whereas G. hokouensis selected holes that were open at both ends (facilitating escape from predators). When we experimentally excluded E. longicaudata from its preferred nesting area, G. hokouensis not only nested in higher abundances, but also modified its nest-site selection, such that communal nesting was more prevalent and both open and closed-in holes were used equally. Egg viability was unaffected by the choice of hole type, but was reduced slightly (by 7%) in the predator exclusion area (presumably due to higher local incubation temperatures). Our field experiment demonstrates that intraguild predators can directly influence the nest density of prey by altering maternal nest-site selection behavior, even when the predator and prey are active at different times of day and the eggs are not at risk of predation.

  20. Observations of sea turtles nesting on Misali islan, Pemba | Pharoah ...

    African Journals Online (AJOL)

    A nest-recording programme has collected data over five years from turtles nesting on Misali Island, off the West coast of Pemba, Tanzania. Five species of sea turtle are known to occur in Zanzibar waters, two of these species nested regularly on the island, with green turtle nests outnumbering hawksbill turtle nests by a ...

  1. Rats and seabirds: effects of egg size on predation risk and the potential of conditioned taste aversion as a mitigation method.

    Science.gov (United States)

    Latorre, Lucía; Larrinaga, Asier R; Santamaría, Luis

    2013-01-01

    Seabirds nesting on islands are threatened by invasive rodents, such as mice and rats, which may attack eggs, chicks and even adults. The low feasibility of rat eradications on many islands makes the development of alternate control plans necessary. We used a combination of field experiments on a Mediterranean island invaded by black rats (Rattusrattus) to evaluate (1) the predation risk posed to different-sized seabird eggs and (2), the potential of two deterrent methods (electronic and chemical) to reduce its impact. Rats were able to consume eggs of all sizes (12 to 68 g), but survival increased 13 times from the smallest to the largest eggs (which also had more resistant eggshells). Extrapolation to seabird eggs suggests that the smallest species (Hydrobatespelagicus) suffer the most severe predation risk, but even the largest (Larusmichahellis) could suffer >60% mortality. Nest attack was not reduced by the deterrents. However, chemical deterrence (conditioned taste aversion by lithium chloride) slowed the increase in predation rate over time, which resulted in a three-fold increase in egg survival to predation as compared to both control and electronic deterrence. At the end of the experimental period, this effect was confirmed by a treatment swap, which showed that conferred protection remains at least 15 days after cessation of the treatment. Results indicate that small seabird species are likely to suffer severe rates of nest predation by rats and that conditioned taste aversion, but not electronic repellents, may represent a suitable method to protect colonies when eradication or control is not feasible or cost-effective.

  2. 78 FR 76248 - Special Conditions: Airbus, Model A350-900 Series Airplane; Side Stick Controller

    Science.gov (United States)

    2013-12-17

    ... one hand. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These proposed special conditions contain the additional safety standards...-hand operation by wrist and not by arms. Discussion Special conditions for Airbus side stick...

  3. Preparation of graphene by electrical explosion of graphite sticks.

    Science.gov (United States)

    Gao, Xin; Xu, Chunxiao; Yin, Hao; Wang, Xiaoguang; Song, Qiuzhi; Chen, Pengwan

    2017-08-03

    Graphene nanosheets were produced by electrical explosion of high-purity graphite sticks in distilled water at room temperature. The as-prepared samples were characterized by various techniques to find different forms of carbon phases, including graphite nanosheets, few-layer graphene, and especially, mono-layer graphene with good crystallinity. Delicate control of energy injection is critical for graphene nanosheet formation, whereas mono-layer graphene was produced under the charging voltage of 22.5-23.5 kV. On the basis of electrical wire explosion and our experimental results, the underlying mechanism that governs the graphene generation was carefully illustrated. This work provides a simple but innovative route for producing graphene nanosheets.

  4. METODE TALKING STICK DENGAN MEDIA AUDIO UNTUK MENINGKATKAN MOTIVASI BELAJAR SISWA PADA MATA PELAJARAN STENOGRAFI

    Directory of Open Access Journals (Sweden)

    Wahyuni Sri Utami

    2015-03-01

    Full Text Available Stenography learning in class X Office Administration 3 at SMK Negeri 1Pemalang indicated the low learning motivation. The purpose of this research was toknow the students’ learning motivation improvement after using talking stick methodwith audio media at Stenography subject in class X Office Administration at SMK N 1Pemalang. It was a classroom action research conducted in three cycles which eachcycle was consisted of planning, implementation, observation, and reflection. The datawere collected by observation and test. Then, the data were analyzed by percentagedescriptive. The results showed that talking stick method with audio media can improvestudents' motivation at Stenography subject in class X Office Administration 3 at SMKN 1 Pemalang. The average of students’ motivation on the first cycle was 63.08%, thenincreased up to 72.08% on the second cycle and finally, it went up to 85.08% on thethird cycle.

  5. Novel hockey-stick mesogens with the nematic, synclinic and anticlinic smectic C phase sequence

    Czech Academy of Sciences Publication Activity Database

    Novotná, Vladimíra; Žurek, J.; Kozmik, V.; Svoboda, J.; Glogarová, Milada; Kroupa, Jan; Pociecha, D.

    2008-01-01

    Roč. 35, č. 8 (2008), 1023-1036 ISSN 0267-8292 R&D Projects: GA AV ČR IAA100100710 Institutional research plan: CEZ:AV0Z10100520 Keywords : liquid crystals * synclinic and anticlinic ordering * hockey-stick mezogens Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.132, year: 2008

  6. MolPrint3D: Enhanced 3D Printing of Ball-and-Stick Molecular Models

    Science.gov (United States)

    Paukstelis, Paul J.

    2018-01-01

    The increased availability of noncommercial 3D printers has provided instructors and students improved access to printing technology. However, printing complex ball-and-stick molecular structures faces distinct challenges, including the need for support structures that increase with molecular complexity. MolPrint3D is a software add-on for the…

  7. "Sticking Together": The Adolescent Experience of the Cohesion Process in Rural School Counseling Groups

    Science.gov (United States)

    Gray, Tara M.; Rubel, Deborah

    2018-01-01

    The purpose of this study was to develop a grounded theory of how adolescents experience the cohesion process in rural school counseling groups. A total of 20 individual interviews with 7 participants were conducted. Data analysis generated the central category of the cohesion process as "sticking together," which describes a "tight…

  8. Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests

    OpenAIRE

    Marie-Andrée Giroux; Myriam Trottier-Paquet; Joël Bêty; Vincent Lamarre; Nicolas Lecomte

    2016-01-01

    Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica) defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter ?conspicuous ...

  9. Study on adsorption behavior of radioiodine gas using incense stick aerosol

    International Nuclear Information System (INIS)

    Murata, Mikio; Noguchi, Hiroshi; Kato, Shohei; Kokubu, Morinobu

    1987-01-01

    Adsorption of radioactive elemental iodine gas ( 131 I 2 ) on incense stick aerosol particles has been studied to provide basic data for a realistic and precise assessment of dose to the public due to radioiodine released from nuclear facilities. A mixture of iodine gas and aerosol was passed once through a glass vessel to cause the adsorption reaction. The adsorption was studied at different reaction times, initial I 2 gas concentrations and particle number concentrations. The results showed that the adsorption reached an equilibrium in about 2 min at the initial I 2 gas concentration of 10 -10 g/cm 3 . The proportion of iodine adsorbed by the aerosol particles was almost constant, about 25 % at the initial I 2 gas concentrations below 10 -11 g/cm 3 and at the reaction time of 1 min, and decreased with increase of the initial concentration over 10 -11 g/cm 3 . The adsorption isotherm of the aerosol for the gas was obtained from the experimental data. The semi-empirical equations to explain the adsorption reaction were also obtained based on the experimental data and the FUCHS's equation relating to vaporization of a droplet. The sticking probability in the equations was estimated to be 7.6 x 10 -3 . The calculated results using the equations were in good agreement with the experimental ones. (author)

  10. Reticulate evolution in stick insects: the case of Clonopsis (Insecta Phasmida).

    Science.gov (United States)

    Milani, Liliana; Ghiselli, Fabrizio; Pellecchia, Marco; Scali, Valerio; Passamonti, Marco

    2010-08-25

    Phasmids show noteworthy abilities to overcome species-specific reproductive isolation mechanisms, including hybridization, polyploidy, parthenogenesis, hybridogenesis and androgenesis. From an evolutionary standpoint, such tangled reproductive interactions lead to the complex phyletic relationships known as "reticulate evolution". Moroccan stick insects of the genus Clonopsis include one bisexual (C. felicitatis) and two closely related parthenogenetic forms (C. gallica, C. soumiae), which represent a polyploid series in chromosome number, but with apparent diploid karyotypes. Moreover, two Clonopsis strains of ameiotic males have been described, C. androgenes-35 and C. androgenes-53. As a consequence, Clonopsis stick insects may have experienced complex micro-evolutionary events, which we try to disentangle in this study. Mitochondrial cox2 analysis supports a recent divergence of Clonopsis, while AFLPs evidence genetic differentiation not linked to karyotypes, so that parthenogenetic C. gallica and C. soumiae appear to be a mix of strains of polyphyletic origin rather than single parthenogenetic species. Moreover, an admixed hybrid origin seems to be confirmed for C. androgenes. On the whole, Clonopsis is an intriguing case of reticulate evolution. Actually, complex cladogenetic events should be taken into account to explain the observed genetic structure, including diploidization of polyploid karyotypes, possibly coupled with hybridization and androgenesis. We also proposed a "working hypothesis" to account for the observed data, which deserves further studies, but fits the observed data very well.

  11. Efficient processing of containment queries on nested sets

    NARCIS (Netherlands)

    Ibrahim, A.; Fletcher, G.H.L.

    2013-01-01

    We study the problem of computing containment queries on sets which can have both atomic and set-valued objects as elements, i.e., nested sets. Containment is a fundamental query pattern with many basic applications. Our study of nested set containment is motivated by the ubiquity of nested data in

  12. Conservation implications when the nest predators are known

    Science.gov (United States)

    Ribic, Christine; Thompson, Frank

    2012-01-01

    Conservation and management of passerines has largely focused on habitat manipulation or restoration because the natural communities on which these birds depend have been destroyed and fragmented. However, productivity is another important aspect of avian conservation, and nest predation can be a large source of nesting mortality for passerines. Recent studies using video surveillance to identify nest predators allow researchers to start evaluating what methods could be used to mitigate nest predation to help passerines of conservation concern. From recent studies, we identified latitudinal and habitat-related patterns in the importance of predator groups that depredate passerine nests. We then reviewed how knowledge of specific nest predators can benefit conservation of bird species of concern. Mammals were the dominant predator group in northern grasslands. Snakes were the dominant predator group in southern habitats. Fire ants were only a nest predator in southern latitudes. Differences in the importance of predator species or groups were likely the result of both their geographic patterns of distribution and habitat preferences. Some direct and indirect predator control measures developed for waterfowl management potentially could be used to benefit passerine productivity. We reviewed three examples-cowbirds, snakes in shrublands, and ground squirrels in grasslands-to illustrate how different predator control strategies may be needed in different situations. Mitigation of passerine nest predation will need to be based on knowledge of predator communities to be effective. This requires large samples of predation events with identified predators; video technology is essential for this task.

  13. Radiation-induced osteochondroma-like lesion in young rat radius

    International Nuclear Information System (INIS)

    Delgado, E.; Rodriguez, J.I.; Serrada, A.; Tellez, M.; Paniagua, R.

    1985-01-01

    To investigate the effects of radiation on the perichondrial groove of Ranvier in osteochondroma development, the external surface of the distal growth plate of the radius in both forelimbs of 30 ten-day-old rats was exposed to a single low dose of radiation (150 r), which was focused on the perichondrial groove. This induced the formation of a chondrocyte nest at the proximal external edge of the growth plate (five to nine days after irradiation). With advancing longitudinal growth of the bone, the chondrocyte nest occupied a diaphyseal position. At nine to 11 days the chondrocyte nest underwent endochondral ossification. At 13-15 days, this osteochondroma-like lesion began to regress with the disappearance of the chondrocyte nest. After 19-21 days, only an irregularly thickened cortical bone remains at the osteochondroma site. Although the possible role of the growth plate subjacent to the irradiated perichondrial groove must be taken into account, the continuity between the perichondrial groove and the osteochondroma, which is separated from the growth plate by the periosteal ring (bone bark), suggests that the perichondrial groove was involved in osteochondroma-like lesion development

  14. Landscape-moderated bird nest predation in hedges and forest edges

    Science.gov (United States)

    Ludwig, Martin; Schlinkert, Hella; Holzschuh, Andrea; Fischer, Christina; Scherber, Christoph; Trnka, Alfréd; Tscharntke, Teja; Batáry, Péter

    2012-11-01

    Landscape-scale agricultural intensification has caused severe declines in biodiversity. Hedges and forest remnants may mitigate biodiversity loss by enhancing landscape heterogeneity and providing habitat to a wide range of species, including birds. However, nest predation, the major cause of reproductive failure of birds, has been shown to be higher in forest edges than in forest interiors. Little is known about how spatial arrangement (configuration) of hedges affects the avian nest predation. We performed an experiment with artificial ground and elevated nests (resembling yellowhammer and whitethroat nests) baited with quail and plasticine eggs. Nests were placed in three habitat types with different degrees of isolation from forests: forest edges, hedges connected to forests and hedges isolated from forests. Nest predation was highest in forest edges, lowest in hedges connected to forests and intermediate in isolated hedges. In the early breeding season, we found similar nest predation on ground and elevated nests, but in the late breeding season nest predation was higher on ground nests than on elevated nests. Small mammals were the main predators of ground nests and appeared to be responsible for the increase in predation from early to late breeding season, whereas the elevated nests were mainly depredated by small birds and small mammals. High predation pressure at forest edges was probably caused by both forest and open-landscape predators. The influence of forest predators may be lower at hedges, leading to lower predation pressure than in forest edges. Higher predation pressure in isolated than connected hedges might be an effect of concentration of predators in these isolated habitats. We conclude that landscape configuration of hedges is important in nest predation, with connected hedges allowing higher survival than isolated hedges and forest edges.

  15. Timing, Nest Site Selection and Multiple Breeding in House Martins: Age-Related Variation and the Preference for Self-Built Mud Nests

    NARCIS (Netherlands)

    Piersma, T.

    2013-01-01

    Almost all accounts of the reproductive biology of House Martins Delichon urbicum are based on studies of birds breeding in artificial nests that are monitored every few days. Here, I provide a study on House Martins using self-built mud nests at a single colony in Gaast, The Netherlands (225 nest

  16. Timing, nest site selection and multiple breeding in House Martins : age-related variation and the preference for self-built mud nests

    NARCIS (Netherlands)

    Piersma, Theunis

    2013-01-01

    Almost all accounts of the reproductive biology of House Martins Delichon urbicum are based on studies of birds breeding in artificial nests that are monitored every few days. Here, I provide a study on House Martins using self-built mud nests at a single colony in Gaast, The Netherlands (225 nest

  17. Does cooperation mean kinship between spatially discrete ant nests?

    Science.gov (United States)

    Procter, Duncan S; Cottrell, Joan E; Watts, Kevin; A'Hara, Stuart W; Hofreiter, Michael; Robinson, Elva J H

    2016-12-01

    Eusociality is one of the most complex forms of social organization, characterized by cooperative and reproductive units termed colonies. Altruistic behavior of workers within colonies is explained by inclusive fitness, with indirect fitness benefits accrued by helping kin. Members of a social insect colony are expected to be more closely related to one another than they are to other conspecifics. In many social insects, the colony can extend to multiple socially connected but spatially separate nests (polydomy). Social connections, such as trails between nests, promote cooperation and resource exchange, and we predict that workers from socially connected nests will have higher internest relatedness than those from socially unconnected, and noncooperating, nests. We measure social connections, resource exchange, and internest genetic relatedness in the polydomous wood ant Formica lugubris to test whether (1) socially connected but spatially separate nests cooperate, and (2) high internest relatedness is the underlying driver of this cooperation. Our results show that socially connected nests exhibit movement of workers and resources, which suggests they do cooperate, whereas unconnected nests do not. However, we find no difference in internest genetic relatedness between socially connected and unconnected nest pairs, both show high kinship. Our results suggest that neighboring pairs of connected nests show a social and cooperative distinction, but no genetic distinction. We hypothesize that the loss of a social connection may initiate ecological divergence within colonies. Genetic divergence between neighboring nests may build up only later, as a consequence rather than a cause of colony separation.

  18. The Role of Non-Foraging Nests in Polydomous Wood Ant Colonies.

    Science.gov (United States)

    Ellis, Samuel; Robinson, Elva J H

    2015-01-01

    A colony of red wood ants can inhabit more than one spatially separated nest, in a strategy called polydomy. Some nests within these polydomous colonies have no foraging trails to aphid colonies in the canopy. In this study we identify and investigate the possible roles of non-foraging nests in polydomous colonies of the wood ant Formica lugubris. To investigate the role of non-foraging nests we: (i) monitored colonies for three years; (ii) observed the resources being transported between non-foraging nests and the rest of the colony; (iii) measured the amount of extra-nest activity around non-foraging and foraging nests. We used these datasets to investigate the extent to which non-foraging nests within polydomous colonies are acting as: part of the colony expansion process; hunting and scavenging specialists; brood-development specialists; seasonal foragers; or a selfish strategy exploiting the foraging effort of the rest of the colony. We found that, rather than having a specialised role, non-foraging nests are part of the process of colony expansion. Polydomous colonies expand by founding new nests in the area surrounding the existing nests. Nests founded near food begin foraging and become part of the colony; other nests are not founded near food sources and do not initially forage. Some of these non-foraging nests eventually begin foraging; others do not and are abandoned. This is a method of colony growth not available to colonies inhabiting a single nest, and may be an important advantage of the polydomous nesting strategy, allowing the colony to expand into profitable areas.

  19. Some problems of the origin of galaxy nests

    International Nuclear Information System (INIS)

    Metlov, V.G.

    1979-01-01

    The origin of galaxy nests have been studied. The nests of galaxies consist of a few (more than two) galaxies in contact with each other and strongly distorted by mutual interaction. Their colour, geometrical and morphological characteristics are compared with ones of ordinary galaxies and groups of galaxies. Conclusions are drawn that 5% to 15% of the total number of nests may be the evolutionary products of tight groups of galaxies (with diameter 11 Msub(Sun)). About half of such objects consist of elliptical galaxies. Galaxies in sufficiently tight groups may merge in consequence of dynamical friction. The remaining (85-95%) nests origin may be possibly explained by different kinds of instabilities in certain flat galaxies, with transformation of one galaxy to the nest, or by interaction of two galaxies containing large amounts of gas and consequent intensive star formation in very large regions, or by other causes. To establish relative contribution of each possible phenomenon in nests origin, it is required to carry out further detailed investigations of these objects

  20. No evidence for UV-based nest-site selection in sticklebacks

    Directory of Open Access Journals (Sweden)

    Bakker Theo CM

    2006-11-01

    Full Text Available Abstract Background Nests are built in various animal taxa including fish. In systems with exclusive male parental care, the choice of a nest site may be an important component of male fitness. The nest site may influence male attractiveness as a mate, and male, embryo, and juvenile survival probabilities. Reproductively active three-spined stickleback males establish and defend a territory in which they build a nest. Territories can differ remarkably in qualities that influence male and female reproductive success like predation risk or abiotic factors such as dissolved oxygen concentration or lighting conditions. The latter may be important because in sticklebacks the extended visual capability into the ultraviolet (UV wave range plays a role in female mate choice. Males are thus expected to be choosy about the habitat in which they will build their nest. Results We tested nest-site choice in male three-spined sticklebacks with respect to different UV lighting conditions. Reproductively active males were given the simultaneous choice to build their nest either in an UV-rich (UV+ or an UV-lacking (UV- environment. Males exhibited no significant nest-site preferences with respect to UV+ or UV-. However, larger males and also heavier ones completed their nests earlier. Conclusion We found that UV radiation as well as differences in luminance had no influence on nest-site choice in three-spined sticklebacks. Males that built in the UV-rich environment were not different in any trait (body traits and UV reflection traits from males that built in the UV-poor environment. There was a significant effect of standard length and body mass on the time elapsed until nest completion in the UV experiment. The larger and heavier a male, the faster he completed his nest. In the brightness control experiment there was a significant effect only of body mass on the duration of nest completion. Whether nest building preferences with respect to UV lighting

  1. Variation in clutch size in relation to nest size in birds

    OpenAIRE

    Moller Anders P.; Adriaensen Frank; Artemyev Alexandr; Banbura Jerzy; Barba Emilio; Biard Clotilde; Blondel Jacques; Bouslama Zihad; Bouvier Jean-Charles; Camprodon Jordi; Cecere Francesco; Charmantier Anne; Charter Motti; Cichon Mariusz; Cusimano Camillo

    2014-01-01

    © 2014 The Authors. Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of egg-laying. Parent birds should be selected to choose nest sites and to build optimally sized nests, yet our current understanding of clutch size-nest size relationships is limited...

  2. Micro transflection on a metallic stick: an innovative approach of reflection infrared spectroscopy for minimally invasive investigation of painting varnishes.

    Science.gov (United States)

    Rosi, Francesca; Legan, Lea; Miliani, Costanza; Ropret, Polonca

    2017-05-01

    A new analytical approach, based on micro-transflection measurements from a diamond-coated metal sampling stick, is presented for the analysis of painting varnishes. Minimally invasive sampling is performed from the varnished surface using the stick, which is directly used as a transflection substrate for micro Fourier transform infrared (FTIR) measurements. With use of a series of varnished model paints, the micro-transflection method has been proved to be a valuable tool for the identification of surface components thanks to the selectivity of the sampling, the enhancement of the absorbance signal, and the easier spectral interpretation because the profiles are similar to transmission mode ones. Driven by these positive outcomes, the method was then tested as tool supporting noninvasive reflection FTIR spectroscopy during the assessment of varnish removal by solvent cleaning on paint models. Finally, the integrated analytical approach based on the two reflection methods was successfully applied for the monitoring of the cleaning of the sixteenth century painting Presentation in the Temple by Vittore Carpaccio. Graphical Abstract Micro-transflection FTIR on a metallic stick for the identification of varnishes during painting cleanings.

  3. The Rufous Hornero (Furnarius rufus) nest as an incubation chamber.

    Science.gov (United States)

    Shibuya, Felipe L S; Braga, Talita V; Roper, James J

    2015-01-01

    Foraging and incubation are mutually exclusive activities for parent birds. A trade-off is generated when a combination of food availability and temperature regulation force birds to choose one and neglect the other, at least temporarily. The Rufous Hornero builds large, oven-like, mud nests, the evolutionary cause of which remains unknown. We tested that temperature variation inside the nest is that which is expected if one function of the nest were for temperate regulation. If so, this would suggest that the nest works as an incubation chamber (but which now may serve more than one function). We divided nests into two natural treatments: nests that received more continuous direct sunshine (sun), and those that received less direct sunshine, due to shade from trees or buildings (shade). Thermometer data loggers were placed in the nest cavity and outside, in the shade of the nest, and temperature was measured every 10min. We predicted that temperatures would consistently be higher and less variable in nests than outside nests. Also, at higher ambient temperatures the nest would function better as an incubation chamber as a consequence of having evolved in a hotter climate. Thus, in Curitiba, where temperatures are lower than where the species (and nest) evolved, nests in greater sunshine should have thermal characteristics that support the incubation chamber hypothesis. Predictions were supported: with Repeated Measures ANOVA and t-tests, we found that temperatures were more constant and higher in nests, especially when in the sun, and as the season progressed (hotter ambient temperatures). We conclude that the large mud nest of the Rufous Hornero works as an incubation chamber that likely evolved to help resolve the incubation-foraging trade-off in the very seasonal and hot regions where the bird evolved. Thus, as an incubation chamber, the nest allows the bird to forage rather than incubate thereby resolving the foraging-incubation trade-off and potentially

  4. PERBEDAAN HASIL BELAJAR SISWA MENGGUNAKAN MODEL PEMBELAJARAN TIPE TALKING STICK DENGAN PEMBELAJARAN KONVENSIONAL PADAMATA PELAJARAN EKONOMI SISWA KELAS X SMAN 1 BONJOL KABUPATEN PASAMAN

    Directory of Open Access Journals (Sweden)

    Cici Idrus

    2013-10-01

    Full Text Available Riset didasari oleh hasil belajar ekonomi kelas X SMAN 1 Bonjol yang masih rendah, yang masih memakai metode Teacher Center Learning, sehingga para siswa kurang aktifi dan kreatif. Satu usaha untuk meningkatkan hasil pelajaran siswa adalah dengan menerapkan jenis model pelajaran ekonomi Talking Stick. Tujuan Studi ini untuk menentukan perbedaan antara hasil belajar menggunakan metode Talking Stick dan konvensional pada kelas X SMAN 1 Bonjol. Riset ini adalah semacam eksperimen. Populasi Studi adalah suatu para siswa nilai/kelas X Sma Negeri 1 Bonjol, sedangkan kelas X3 menggunakan jenis model pelajaran Talking Stick sebagai kelas eksperimen dan X4 Kelas sebagai kelas yag dikendalikan dengan metode konvensional. Hasil menunjukkan rata-rata hasil belajar kelas eksperimen lebih tinggi( 79.62 dibanding kelas kontrol ( 73.21. Pada hasil pengujian hipotesis yang menggunakan SPSS versi 16. nilai yang diperoleh t= 2.892 dan t tabel= 1.671 maka> ttable kemudian Tolak H0 dan menerima H1. Maka dapat disimpulkan bahwa Ada perbedaan penting pada hasil pelajaran siswa yang menggunakan tipe Talking Stick dan konvensional pada mata pelajaran ekonomi kelas X SMAN 1 Bonjol.

  5. Nest temperature fluctuations in a cavity nester, the southern ground-hornbill.

    Science.gov (United States)

    Combrink, L; Combrink, H J; Botha, A J; Downs, C T

    2017-05-01

    Southern ground-hornbills Bucorvus leadbeateri inhabit savanna and bushveld regions of South Africa. They nest in the austral summer, which coincides with the wet season and hottest daytime temperatures in the region. They are secondary cavity nesters and typically nest in large cavities in trees, cliffs and earth banks, but readily use artificial nest boxes. Southern ground-hornbills are listed as Endangered in South Africa, with reintroductions into suitable areas highlighted as a viable conservation intervention for the species. Nest microclimate, and the possible implications this may have for the breeding biology of southern ground-hornbills, have never been investigated. We used temperature dataloggers to record nest cavity temperature and ambient temperature for one artificial and 11 natural southern ground-hornbill tree cavity nests combined, spanning two breeding seasons. Mean hourly nest temperature, as well as mean minimum and mean maximum nest temperature, differed significantly between southern ground-hornbill nests in both breeding seasons. Mean nest temperature also differed significantly from mean ambient temperature for both seasons. Natural nest cavities provided a buffer against the ambient temperature fluctuations. The artificial nest provided little insulation against temperature extremes, being warmer and cooler than the maximum and minimum local ambient temperatures, respectively. Nest cavity temperature was not found to have an influence on the breeding success of the southern ground-hornbill groups investigated in this study. These results have potentially important implications for southern ground-hornbill conservation and artificial nest design, as they suggest that the birds can tolerate greater nest cavity temperature extremes than previously thought. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Vessel Enhancement and Segmentation of 4D CT Lung Image Using Stick Tensor Voting

    Science.gov (United States)

    Cong, Tan; Hao, Yang; Jingli, Shi; Xuan, Yang

    2016-12-01

    Vessel enhancement and segmentation plays a significant role in medical image analysis. This paper proposes a novel vessel enhancement and segmentation method for 4D CT lung image using stick tensor voting algorithm, which focuses on addressing the vessel distortion issue of vessel enhancement diffusion (VED) method. Furthermore, the enhanced results are easily segmented using level-set segmentation. In our method, firstly, vessels are filtered using Frangi's filter to reduce intrapulmonary noises and extract rough blood vessels. Secondly, stick tensor voting algorithm is employed to estimate the correct direction along the vessel. Then the estimated direction along the vessel is used as the anisotropic diffusion direction of vessel in VED algorithm, which makes the intensity diffusion of points locating at the vessel wall be consistent with the directions of vessels and enhance the tubular features of vessels. Finally, vessels can be extracted from the enhanced image by applying level-set segmentation method. A number of experiments results show that our method outperforms traditional VED method in vessel enhancement and results in satisfied segmented vessels.

  7. The evolution of cerebellum structure correlates with nest complexity.

    Science.gov (United States)

    Hall, Zachary J; Street, Sally E; Healy, Susan D

    2013-01-01

    Across the brains of different bird species, the cerebellum varies greatly in the amount of surface folding (foliation). The degree of cerebellar foliation is thought to correlate positively with the processing capacity of the cerebellum, supporting complex motor abilities, particularly manipulative skills. Here, we tested this hypothesis by investigating the relationship between cerebellar foliation and species-typical nest structure in birds. Increasing complexity of nest structure is a measure of a bird's ability to manipulate nesting material into the required shape. Consistent with our hypothesis, avian cerebellar foliation increases as the complexity of the nest built increases, setting the scene for the exploration of nest building at the neural level.

  8. Orientation with a Viking sun-compass, a shadow-stick, and two calcite sunstones under various weather conditions.

    Science.gov (United States)

    Bernáth, Balázs; Blahó, Miklós; Egri, Adám; Barta, András; Kriska, György; Horváth, Gábor

    2013-09-01

    It is widely accepted that Vikings used sun-compasses to derive true directions from the cast shadow of a gnomon. It has been hypothesized that when a cast shadow was not formed, Viking navigators relied on crude skylight polarimetry with the aid of dichroic or birefringent crystals, called "sunstones." We demonstrate here that a simple tool, that we call "shadow-stick," could have allowed orientation by a sun-compass with satisfying accuracy when shadows were not formed, but the sun position could have reliably been estimated. In field tests, we performed orientation trials with a set composed of a sun-compass, two calcite sunstones, and a shadow-stick. We show here that such a set could have been an effective orientation tool for Vikings only when clear, blue patches of the sky were visible.

  9. Nested cellular automata

    International Nuclear Information System (INIS)

    Quasthoff, U.

    1985-07-01

    Cellular automata by definition consist of a finite or infinite number of cells, say of unit length, with each cell having the same transition function. These cells are usually considered as the smallest elements and so the space filled with these cells becomes discrete. Nevertheless, large pictures created by such cellular automata look very fractal. So we try to replace each cell by a couple of smaller cells, which have the same transition functions as the large ones. There are automata where this replacement does not destroy the macroscopic structure. In these cases this nesting process can be iterated. The paper contains large classes of automata with the above properties. In the case of one dimensional automata with two states and next neighbour interaction and a nesting function of the same type a complete classification is given. (author)

  10. Fleas (Siphonaptera) in the Nests of Dormice (Gliridae: Rodentia) in Lithuania.

    Science.gov (United States)

    Lipatova, I; Stanko, M; Paulauskas, A; Spakovaite, S; Gedminas, V

    2015-05-01

    Negative effects of flea (Siphonaptera) parasitism on the host may be expressed in different ways. The aim of this study was to assess distribution of the flea fauna in nests of dormice in Lithuania. Nests of Glis glis (L.), Dryomys nitedula (Pallas), and Muscardinus avellanarius (L.) were collected from nest boxes in 2012 and 2013. Fleas were collected from nests in the laboratory and put into plastic tubes with 70% ethanol. Flea species were identified using morphological keys. From 400 nest boxes, 112 nests of dormice were collected from eight sites from mixed forests of central Lithuania. Twenty-three nests of G. glis were collected from nest boxes, with 16 of them containing 286 fleas belonging to four species: Ceratophyllus sciurorum (Schrank) (259), C. gallinae (Schrank) (23), Hystrichopsylla talpae (Curtis) (3), and Megabothris turbidus (Rothschild) (1). Fourteen nests of M. avellanarius were collected from nest boxes, 4 of which contained 224 fleas belonging to two species: C. sciurorum (221) and C. gallinae (3). Twenty-four nests of D. nitedula were collected from nest boxes, including 17 containing 207 fleas belonging to two species: C. sciurorum (205) and C. gallinae (2). Fifty-one nests of undetermined dormice species also were collected from nest boxes, 12 of them contained 395 fleas belonging to three species: C. sciurorum (374), Ctenophthalmus agyrtes (Heller) (19), and Ctenophthalmus assimilis (Taschenberg) (2). C. sciurorum was a predominant species in the nests of dormice. The occurrence of C. gallinae was documented in Lithuania for the first time. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. From neurons to nests : nest-building behaviour as a model in behavioural and comparative neuroscience

    OpenAIRE

    Hall, Zachary Jonas; Meddle, Simone L; Healy, Susan Denise

    2015-01-01

    This work was supported by funding from the Biotechnology and Biological Sciences Research Council (BB/ I019502/1 to SDH and SLM) and the Natural Sciences and Engineering Research Council of Canada (grant number PGSD3-409582-2011 to ZJH) and Roslin Institute Strategic Grant funding from the Biotechnology and Biological Sciences Research Council (SLM). Despite centuries of observing the nest building of most extant bird species, we know surprisingly little about how birds build nests and, s...

  12. Quaternary studies in the Paradox Basin, southeastern Utah

    International Nuclear Information System (INIS)

    Biggar, N.

    1987-08-01

    Studies have included paleoclimatic assessments and evaluation of the Needles Fault zone, and an assessment of geologic age dating results and techniques. Fossil pollen, snail shells, pack rat middens, and Holocene stratigraphic units have been examined as potential paleoclimatic indicators. Of these, the most definitive data have been an interpreted 13,000-year vegetation record found in the pack rat middens. This record defines the late Pleistocene-Holocene climatic transition at approximately 10,000 years ago, and indicates that temperature decreased and precipitation increased during the late Pleistocene relative to the present. In the Needles Fault zone, age dating results and geomorphic studies indicate that the northeastern grabens may be the youngest and that the system is at least 65,000 years old. Using this date and an assumed Colorado River incision rate, the maximum rate at which grabens have spread eastward from the river canyon can be estimated. The most useful age dating techniques for the Paradox Basin are the accumulation of pedogenic carbonate in the soil profile, radiocarbon dating, thermoluminescence dating, amino acid diagenesis of mollusk shells, paleomagnetic analysis of early Pleistocene deposits, and topographic position of deposits and surfaces. Method applicability depends on the datable materials present, the estimated age of the sample or deposit, and potential contaminants that could affect analysis. 108 refs., 64 figs., 35 tabs

  13. Stable Isotopic Shifts in Fish Bones from Multiple Archeological Coastal Middens in Penobscot Bay, Maine

    Science.gov (United States)

    Harris, C.; Johnson, B.; Ambrose, W. G.; Bourque, B.; Dostie, P.; Crowley, E.

    2010-12-01

    The carbon and nitrogen stable isotope compositions of collagen extracted from well-preserved archeological fish bones has the potential to provide useful information on fish diets and food web dynamics over time. Previous work on the Turner Farm archaeological site in Penobscot Bay, Gulf of Maine, reveals significant shifts in fish diets have occurred since European colonization (post 1620’s). The objective of the present study was to analyze samples from other archaeological sites within Penobscot Bay to characterize the spatial extent of the isotopic shift measured at Turner Farm. Stratified cod, flounder, and sculpin bones were analyzed from eight coastal middens located approximately 50km apart from one another within Penobscot Bay. The bones were sampled from three time horizons (0kya, 0.5-1kya, and 2.2-2.4kya). All bone samples were demineralized in 0.2M HCl at 4°C for 2 to 7 days and then extracted in 0.25M NaOH at 4°C for 1 to 2 hours. After freeze-drying, the bulk isotopic composition of each sample was analyzed using the EA-IRMS. In all stratigraphic horizons analyzed, cod were more enriched in δ13C and δ15N than sculpin, and flounder were the most depleted in δ13C and δ15N . However, the isotopic offsets between the fish species decreased from 2.4kya to the present. The nitrogen isotope composition was relatively constant over time and space for all species, implying that trophic levels for the fishes analyzed have not changed significantly in Penobscot Bay for the last 2,400 years. The carbon isotope composition also appears to be constant spatially in Penobscot Bay, however, the modern signal was more depleted than the paleo signal in all three species. The difference between the modern and paleo δ13C is ~5‰ for cod and flounder, and ~9‰ for sculpin. These shifts may, in part, be explained by decreases in both primary producer and prey species diversity, as kelp forests replace eelgrass beds in the Gulf of Maine.

  14. Nest predation research: Recent findings and future perspectives

    Science.gov (United States)

    Chalfoun, Anna D.; Ibanez-Alamo, J. D.; Magrath, R. D.; Schmidt, Kenneth A.; Thomson, R. L.; Oteyza, Juan C.; Haff, T. M.; Martin, T.E.

    2016-01-01

    Nest predation is a key source of selection for birds that has attracted increasing attention from ornithologists. The inclusion of new concepts applicable to nest predation that stem from social information, eavesdropping or physiology has expanded our knowledge considerably. Recent methodological advancements now allow focus on all three players within nest predation interactions: adults, offspring and predators. Indeed, the study of nest predation now forms a vital part of avian research in several fields, including animal behaviour, population ecology, evolution and conservation biology. However, within nest predation research there are important aspects that require further development, such as the comparison between ecological and evolutionary antipredator responses, and the role of anthropogenic change. We hope this review of recent findings and the presentation of new research avenues will encourage researchers to study this important and interesting selective pressure, and ultimately will help us to better understand the biology of birds.

  15. Breeding biology and nest site characteristics of the Rosy-faced ...

    African Journals Online (AJOL)

    Nine colonies, comprising 20 nests, were monitored every four days to establish incubation and fledging periods. Rearing and fledging of chicks was found to be successful in eight nests. Measurements of 18 young from four nests were used to monitor growth rate. Nesting success was calculated at 0.1, following the ...

  16. Coping with shifting nest predation refuges by European reed Warblers Acrocephalus scirpaceus.

    Directory of Open Access Journals (Sweden)

    Lucyna Halupka

    Full Text Available Predation, the most important source of nest mortality in altricial birds, has been a subject of numerous studies during past decades. However, the temporal dynamics between changing predation pressures and parental responses remain poorly understood. We analysed characteristics of 524 nests of European reed warblers monitored during six consecutive breeding seasons in the same area, and found some support for the shifting nest predation refuge hypothesis. Nest site characteristics were correlated with nest fate, but a nest with the same nest-site attributes could be relatively safe in one season and vulnerable to predation in another. Thus nest predation refuges were ephemeral and there was no between-season consistency in nest predation patterns. Reed warblers that lost their first nests in a given season did not disperse farther for the subsequent reproductive attempt, compared to successful individuals, but they introduced more changes to their second nest sites. In subsequent nests, predation risk remained constant for birds that changed nest-site characteristics, but increased for those that did not. At the between-season temporal scale, individual birds did not perform better with age in terms of reducing nest predation risk. We conclude that the experience acquired in previous years may not be useful, given that nest predation refuges are not stable.

  17. Observer visitation frequency and success of mourning dove nests: A field experiment

    Science.gov (United States)

    Nichols, J.D.; Percival, H.F.; Coon, R.A.; Conroy, M.J.; Hensler, G.L.; Hines, J.E.

    1984-01-01

    Field studies of nesting success generally require visits by the investigator to the nests under study. Such visits may themselves influence nesting success, however, and this possibility has been discussed and investigated by a number of workers with a variety of bird species. Livezey (1980) reviewed the relevant literature for duck nests and noted that most studies failed to demonstrate differences in nesting success between visited nests and those not visited. Livezey (1980) found in his own work that nest abandonment may have occurred as a result of disturbance by observers but that nest predation was not related to time spent by observers at nests or number of observers approaching nests. Various components of nesting and breeding success in seabirds are thought to be adversely affected by human disturbance and nest visitation (Gillett et al. 1975, Robert and Ralph 1975, Ollason and Dunnet 1980). Upland, ground-nesting species have also been studied (e.g. Stoddard 1931, Evans and Wolfe 1967, Henry 1969, Roseberry and Klimstra 1970, Klimstra and Roseberry 1975), and, although conclusions have varied, a number of these workers found no effect of observers on nest-predation rates.

  18. Waffle production: influence of batter ingredients on sticking of waffles at baking plates-Part II: effect of fat, leavening agent, and water.

    Science.gov (United States)

    Huber, Regina; Schoenlechner, Regine

    2017-05-01

    Fresh egg waffles are continuously baked in tunnel baking ovens in industrial scale. Waffles that partly or fully stick to the baking plates cause significant product loss and increased costs. The aim of this study was, therefore, to investigate the effect of different recipe ingredients on the sticking behavior of waffles. In this second part, ingredients investigated were different leavening agents (sodium acid pyrophosphate, ammonium bicarbonate, magnesium hydroxide carbonate, or monocalcium phosphate), different fat sources (rapeseed oil, cocos fat, butter, or margarine), and different water sources (tap water 12°dH and distilled water). Within the different types of fats, solid fats with high amount of short-chain fatty acids (cocos fat or butter) decreased the number of sticking waffles compared to liquid oils (rapeseed oil). Regarding leavening agents, magnesium hydroxide carbonate and ammonium bicarbonate were superior to sodium acid pyrophosphate or monocalcium phosphate. Between the two water sources, effects were small.

  19. Sandhill crane abundance and nesting ecology at Grays Lake, Idaho

    Science.gov (United States)

    Austin, J.E.; Henry, A.R.; Ball, I.J.

    2007-01-01

    We examined population size and factors influencing nest survival of greater sandhill cranes (Grus canadensis tabida) at Grays Lake National Wildlife Refuge, Idaho, USA, during 1997-2000. Average local population of cranes from late April to early May, 1998-2000, was 735 cranes, 34% higher than that reported for May 1970-1971. We estimated 228 (SE = 30) nests in the basin core (excluding renests), 14% higher than a 1971 estimate. Apparent nest success in our study (x?? = 60%, n = 519 nests) was lower than reported for Grays Lake 30-50 years earlier. Daily survival rates (DSRs) of all nests averaged 0.9707 (41.2%). The best model explaining nest survival included year and water depth and their interaction. Nest survival was highest (DSR = 0.9827) in 1998 compared with other years (0.9698-0.9707). Nest survival changed little relative to water depth in 1998, when flooding was extensive and alternative prey (microtines) irrupted, but declined markedly with lower water levels in 2000, the driest year studied. Hypotheses relating nest survival to vegetation height, land use (idle, summer grazing, fall grazing), and date were not supported. In a before-after-control-impact design using 12 experimental fields, nest survival differed among years but not among management treatments (idle, fall graze, fall burn, and summer-graze-idle rotation), nor was there an interaction between year and treatments. However, DSRs in fall-burn fields declined from 0.9781 in 1997-1998 to 0.9503 in 1999-2000 (posttreatment). Changes in the predator community have likely contributed to declines in nest success since the 1950s and 1970s. Our results did not support earlier concerns about effects of habitat management practices on crane productivity. Nest survival could best be enhanced by managing spring water levels. Managers should continue censuses during late April to evaluate long-term relationships to habitat conditions and management.

  20. Management of western coniferous forest habitat for nesting accipiter hawks

    Science.gov (United States)

    Richard T. Reynolds

    1983-01-01

    Availability of nesting sites can limit accipiter populations. Because accipiters nest in dense forest stands, any alteration that opens these stands is likely to lessen their desirability as nest sites. Tree growth and the associated changes in the vegetative structure of aging nest sites limit the number of years sites will be suitable. Therefore, prospective...

  1. Variation in nest predation among arid-zone birds | Lloyd | Ostrich ...

    African Journals Online (AJOL)

    I examined the nesting habits and success of 11 co-existing species in an arid, sub-tropical habitat in South Africa. Nesting success ranged from 3.5% to 75.4% among species, with predation by mammals and snakes accounting for 94% of nest losses. Differences in predator avoidance behaviour (deserting the nest vs ...

  2. Nesting ecology of Pied Avocet Recurvirostra avosetta in Sfax salina ...

    African Journals Online (AJOL)

    In this paper we use the results of a one-year monitoring of nests in Sfax salina to provide information on its nesting parameters, in particular nesting phenology, colony size and hatching success. Our results show that Pied Avocets formed dense colonies at the beginning of the nesting season, but colony size decreased as ...

  3. 78 FR 67077 - Special Conditions: Airbus, Model A350-900 Series Airplane; Side Stick Controllers

    Science.gov (United States)

    2013-11-08

    ... adequacy under section 611 of Public Law 92-574, the ``Noise Control Act of 1972.'' The FAA issues special... crew. 3. Pilot control: It must be shown by flight tests that the use of side stick controllers does... and roll control instead of conventional wheels and columns. The applicable airworthiness regulations...

  4. High, low, or familiar? Nest site preferences of experienced laying hens.

    Science.gov (United States)

    Krause, E T; Schrader, L

    2018-05-22

    1. The aim of this study was to investigate which nest heights are preferred by laying hens in the absence of familiar nest locations and whether preferred nest heights are more attractive than a familiar location. In two experiments, a total of 108 hens of four different layer breeds, which were at least 50 weeks of age, were studied. 2. In the first experiment, hens were given individual free choice between nests for 1-week at four different heights (0 cm, 39 cm, 78 cm, and 117 cm above ground). Hens of the four breeds differed in their nest height preferences (P = 0.0013). However, hens of three breeds preferred ground level nests (P < 0.007) and the fourth line showed an equal preference for the ground level and level three, the latter level corresponding to the height of the nests in their home compartments. 4. In the second experiment, hens from the four breeds were given a choice between ground level nests and nests at a familiar location, i.e. at the same location as in their home compartment. Hens of all strains preferred the familiar nest location (P = 0.002) and preferences did not differ between strains (P = 0.77). 5. Laying hens seem to prefer nests at ground level in the absence of a familiar nest. However, if possible, experienced 50 week old hens continue to use a familiar nest location instead of a ground nest location. The results are discussed with respect to a potential primary preference that may be modifiable by experience and with respect to possible relevance in commercial housing.

  5. Ecology of a nesting red-shouldered hawk population

    Science.gov (United States)

    Stewart, R.E.

    1949-01-01

    An ecological study of a nesting Red-shouldered Hawk population was made over a 185 square mile area on the Coastal Plain of Maryland in 1947. The courting and nesting season extended from late February until late June.....During the nesting season a combination of fairly extensive flood-plain forest with adjacent clearings appears to meet the major ecological requirements of the Red-shouldered Hawk in this region. A total of 51 pairs was found in the study area, occupying about 42 square miles or 23% of the total area studied. The population density on the land that was suitable for this species was about 1 pair per .8 of a square mile, while the density for the entire study area would be only about 1 pair per 3.6 square miles.....Nests were spaced fairly evenly over most of the flood-plain forests, especially in areas where the width.of the flood plain was relatively constant. There was an inverse correlation between the width of the flood plain and the distances between nests in adjacent territories. The nests were all situated in fairly large trees and were from 28 feet to 77 feet above the ground, averaging 50. They were found in 14 different species of trees, all deciduous.....The Barred Owl and Red-shouldered Hawk were commonly associated together in the same lowland habitats. Other raptores were all largely restricted to upland habitats....The average number of young in 47 occupied nests following the hatching period was 2.7 with extremes of 1 and 4. Only 3 out of 52 nests (6%) were found deserted at this time....The food habits of nestling Red-shouldered Hawks are very diversified. They feed on many types of warm-blooded and cold-blooded vertebrates as well as invertebrates.

  6. Nest success of the Indian House Crow Corvus splendens : An ...

    African Journals Online (AJOL)

    Nest success of the Indian House Crow Corvus splendens was studied in the urban area of Dar es Salaam, Tanzania, in late March to early May 2011. The study investigated nest success of the Indian House Crow in different tree species with varying canopy covers and heights. Fifty-five active nests and 38 inactive nests ...

  7. Landscape and regional context differentially affect nest parasitism and nest predation for Wood Thrush in central Virginia, USA (Presentation)

    Science.gov (United States)

    Many empirical studies have shown that forest-breeding songbirds suffer greater rates of nest predation and nest parasitism in smaller forest patches and in fragmented landscapes. To compare the performance of different metrics of spatial habitat configuration resulting from defo...

  8. Use of Pleurotus sajor-caju in upgrading green jute plants and jute sticks as ruminant feed

    Directory of Open Access Journals (Sweden)

    Zinat Mahal

    2013-01-01

    Full Text Available In this study, superfluous jute plants and jute stick were converted into upgraded animal feed by solid state fermentation (SSF using a cellulolytic fungus, Pleurotus sajor-caju. Prior to fermentation, substrates were subjected to several pretreatments such as soaking with water overnight and alkali or lime pretreatment. SSF was carried out with 20 g of substrate in 100 ml conical flask and was incubated at 30C for 8 weeks. In all treatments, the highest amount of reducing sugar, soluble protein as well as the cellulolytic activities of three enzymes viz. cellobiase, carboxymethyl cellulase and avicelase were obtained at 6th week of fermentation. Compared to raw, unsoaked substrates, soaking treatment alone could produce 10% more soluble protein in both substrates whereas reducing sugar increment was 5% and 6% in jute sticks and jute plants, respectively. From all treatments, combination of soaking and lime treatment in green jute plants yielded higher value than jute sticks in terms of reducing sugar, soluble protein and enzymatic activity. The radiation doses at 20, 30 and 40 kGy appeared to have no effect on sugar and protein accretion. During eight weeks of fermentation, relatively higher cellobiase activity was found compared to that of carboxymethyl cellulase and avicelase. The present investigation indicates that fungal conversion with pretreatment can turn these lignocellulosic agro-wastes to a nutritionally enriched animal feed by increasing the crude protein and reducing sugar content. However, further research is necessary to develop strategies for industrial scale production to overcome the crisis of nutritionally improved animal feed.

  9. Epidemiology of Injuries in Women Playing Competitive Team Bat-or-Stick Sports: A Systematic Review and a Meta-Analysis.

    Science.gov (United States)

    Panagodage Perera, Nirmala Kanthi; Joseph, Corey; Kemp, Joanne Lyn; Finch, Caroline Frances

    2018-03-01

    Team bat-or-stick sports, including cricket, softball and hockey, are popular among women. However, little is known about the injury profile in this population. The aim was to describe the incidence, nature and anatomical location of injuries in bat-or-stick sports played by women in a competitive league. This review was prospectively registered (PROSPERO CRD42015026715). CINAHL, MEDLINE, PsycINFO, PubMed, SPORTDiscus were systematically searched from January 2000 to September 2016, inclusive. Peer-reviewed original research articles reporting the incidence, nature and anatomical location of injuries sustained by women aged 18 + years in competitive bat-or-stick sports were included. Two meta-analyses based on injury incidence proportions (injury IP) and injury rates per 1000 person-days of athletic exposure (AE) were performed. A total of 37 studies satisfied the inclusion criteria, and five had low risk of bias. The weighted injury IP was 0.42 [95% confidence interval (CI) 0.39-0.45]. The weighted injury rate was 6.12 (95% CI 6.05-6.18) overall, and greater in games [15.79 (95% CI 15.65-15.93)] than in practice [3.07 (95% CI 2.99-3.15)]. The ankle was the most commonly injured anatomical location, followed by the hand (including wrist and fingers), knee and head. Soft tissue and ligament injuries were most common types of injuries. Injury prevention in women's sports is a novel and emerging field of research interest. This review highlights that injury incidence is high among female bat-or-stick players, but little information is known about direct causal mechanisms. This review clearly establishes the need for enhancements to injury data collection. Without this information, it will not be possible to develop evidence-based injury prevention interventions.

  10. [Duration of the pre-nesting period and its relation with social organization in sandpipers (Charadrii, Aves) nesting in north-east Yakutia].

    Science.gov (United States)

    Gavrilov, V V

    2013-01-01

    Investigations were carried out at two stations of Ornithological Unit, IBPN FEB RAS, located in Nizhnekolymsk District, Yakutia, starting from May 18-20 in 1984, 1985, 1987, 1988 and 1990. Duration of the pre-nesting period in 11 sandpiper species with different social organization was studied and compared with each other by allometric equations. As a characteristic of bird size the body mass was selected. Sandpipers come flying to the tundra at almost critical temperatures, to begin breeding as early as possible. Tining of breeding depends on birds feeding manner and the proximity to sites of overwintering. Duration of the pre-nesting period is invariable for every bird species and sex. There are sexual distinctions in time spent for the pre-nesting period in jointly-nesting sandpipers. The exponents in allometric equations that relate duration of the pre-nesting period with body mass are constant within a particular sex and differ between males and females. In different sexes, time spent for the pre-nesting period depends on mating, parental, and territorial systems. In sandpipers' males and females, this time is determined by the type of social organization. Relatively large sandpiper species seek to shortening of the pre-nesting period calendar time, which constrains their social organization. Monogamy and pair parental care lead to a necessity for spatial population structure to be controlled more strictly and maintained for a longer time. This, in turn, causes the increasing of males' time expenditures for such a behavior.

  11. Retirement investment theory explains patterns in songbird nest-site choice

    Science.gov (United States)

    Streby, Henry M.; Refsnider, Jeanine M.; Peterson, Sean M.; Andersen, David E.

    2014-01-01

    When opposing evolutionary selection pressures act on a behavioural trait, the result is often stabilizing selection for an intermediate optimal phenotype, with deviations from the predicted optimum attributed to tracking a moving target, development of behavioural syndromes or shifts in riskiness over an individual's lifetime. We investigated nest-site choice by female golden-winged warblers, and the selection pressures acting on that choice by two fitness components, nest success and fledgling survival. We observed strong and consistent opposing selection pressures on nest-site choice for maximizing these two fitness components, and an abrupt, within-season switch in the fitness component birds prioritize via nest-site choice, dependent on the time remaining for additional nesting attempts. We found that females consistently deviated from the predicted optimal behaviour when choosing nest sites because they can make multiple attempts at one fitness component, nest success, but only one attempt at the subsequent component, fledgling survival. Our results demonstrate a unique natural strategy for balancing opposing selection pressures to maximize total fitness. This time-dependent switch from high to low risk tolerance in nest-site choice maximizes songbird fitness in the same way a well-timed switch in human investor risk tolerance can maximize one's nest egg at retirement. Our results also provide strong evidence for the adaptive nature of songbird nest-site choice, which we suggest has been elusive primarily due to a lack of consideration for fledgling survival.

  12. A new bee species that excavates sandstone nests.

    Science.gov (United States)

    Orr, Michael C; Griswold, Terry; Pitts, James P; Parker, Frank D

    2016-09-12

    Humanity has long been fascinated by animals with apparently unfavorable lifestyles [1]. Nesting habits are especially important because they can limit where organisms live, thereby driving population, community, and even ecosystem dynamics [2]. The question arises, then, why bees nest in active termite mounds [3] or on the rim of degassing volcanoes, seemingly preferring such hardship [4]. Here, we present a new bee species that excavates sandstone nests, Anthophora (Anthophoroides) pueblo Orr (described in Supplemental Information, published with this article online), despite the challenges already inherent to desert life. Ultimately, the benefits of nesting in sandstone appear to outweigh the associated costs in this system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Provisioning nest material for Rooks; a potential tool for conservation management

    Directory of Open Access Journals (Sweden)

    Horváth Éva

    2015-06-01

    Full Text Available Active conservation measures often entail supplementing scarce resources, such as food or nesting site to high conservation value species. We hypothesized that adequate nest material in reasonable distance is a scarce resource for Rooks breeding in open grassland habitats of Hungary. Here we show that Rooks willingly utilize large quantities of provided excess nesting material, and that this procedure may alter nest composition, and increase the number of successful pairs. Our results show that while nest height remains constant, twig diameter is significantly larger, the number of twigs used per nest is presumably smaller, and that the ratio of nests with fledglings is higher in a rookery where supplementary twigs were present. Providing twigs and branches in the vicinity of rookeries may serve as an active conservation measure to increase the number of nests in a rookery, and thus the potential number of nesting possibilities for Red-footed Falcons.

  14. Cinereous Vulture Nesting Ecology in Ikh Nartyn Chuluu Nature Reserve, Mongolia

    Directory of Open Access Journals (Sweden)

    Richard P. Reading

    2005-06-01

    Full Text Available Cinereous vultures ( Aegypius monachus are the largest raptors in Eurasia. Little is known about the species, especially in Mongolia. We studied the nesting ecology of cinereous vultures in Ikh Nartyn Chuluu Nature Reserve, Dornogobi Aimag. To assess reproductive success, we located active nests and periodically checked to determine if they remained active. We measured nest sizes and, periodically, nestling sizes and weights. We located 42 active cinereous vulture nests (27 on rocks and 15 on trees in 2003 and 19 nests (14 on rocks and 5 on trees in 2004. Mean volume of active nests was 3.92 ± 0.39 m 3 ( n = 36. Most nests failed prior to egg hatching, but after hatching nesting success rates increased dramatically. Following hatching, cinereous vulture chicks grew linearly until leveling off just prior to fledging. We generated growth curves for chicks that allowed us to determine the average size of chicks on specific dates. Improving the prospects for successful cinereous vulture conservation likely requires a better understanding of nesting ecology. As such, we plan to improve the quality of our data by monitoring nests more intensively to determine incubation and fledging lengths, as well as causes of nest failures.

  15. Nest-site partitioning in a strandveld shrubland bird community ...

    African Journals Online (AJOL)

    Nest-site selection may vary adaptively among co-existing species as a result of competitive interactions among the species or in response to density-dependent nest predation. We examined nest-site characteristics and degree of partitioning among 14 co-existing bird species breeding in dwarf strandveld shrubland at ...

  16. Lifespan analyses of forest raptor nests: patterns of creation, persistence and reuse.

    Directory of Open Access Journals (Sweden)

    María V Jiménez-Franco

    Full Text Available Structural elements for breeding such as nests are key resources for the conservation of bird populations. This is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. The availability of nesting-platforms is influenced by nest creation and persistence. In a Mediterranean forest in southeastern Spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle Aquila pennata, common buzzard Buteo buteo and northern goshawk Accipiter gentilis. From 1998 to 2013, we tracked the fate of 157 nesting-platforms built and reused by these species with the aim of determining the rates of creation and destruction of nesting-platforms, estimating nest persistence by applying two survival analyses, describing the pattern of nest reuse and testing the effects of nest use on breeding success. Nest creation and destruction rates were low (0.14 and 0.05, respectively. Using Kaplan Meier survival estimates and Cox proportional-hazards regression models we found that median nest longevity was 12 years and that this was not significantly affected by nest characteristics, nest-tree dimensions, nest-builder species, or frequency of use of the platform. We also estimated a transition matrix, considering the different stages of nest occupation (vacant or occupied by one of the focal species, to obtain the fundamental matrix and the average life expectancies of nests, which varied from 17.9 to 19.7 years. Eighty six percent of nests were used in at least one breeding attempt, 67.5% were reused and 17.8% were successively occupied by at least two of the study species. The frequency of nest use had no significant effects on the breeding success of any species. We conclude that nesting-platforms constitute an important resource for forest raptors and that their longevity is sufficiently high to allow their reuse in multiple breeding

  17. Lifespan Analyses of Forest Raptor Nests: Patterns of Creation, Persistence and Reuse

    Science.gov (United States)

    Jiménez-Franco, María V.; Martínez, José E.; Calvo, José F.

    2014-01-01

    Structural elements for breeding such as nests are key resources for the conservation of bird populations. This is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. The availability of nesting-platforms is influenced by nest creation and persistence. In a Mediterranean forest in southeastern Spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle Aquila pennata, common buzzard Buteo buteo and northern goshawk Accipiter gentilis. From 1998 to 2013, we tracked the fate of 157 nesting-platforms built and reused by these species with the aim of determining the rates of creation and destruction of nesting-platforms, estimating nest persistence by applying two survival analyses, describing the pattern of nest reuse and testing the effects of nest use on breeding success. Nest creation and destruction rates were low (0.14 and 0.05, respectively). Using Kaplan Meier survival estimates and Cox proportional-hazards regression models we found that median nest longevity was 12 years and that this was not significantly affected by nest characteristics, nest-tree dimensions, nest-builder species, or frequency of use of the platform. We also estimated a transition matrix, considering the different stages of nest occupation (vacant or occupied by one of the focal species), to obtain the fundamental matrix and the average life expectancies of nests, which varied from 17.9 to 19.7 years. Eighty six percent of nests were used in at least one breeding attempt, 67.5% were reused and 17.8% were successively occupied by at least two of the study species. The frequency of nest use had no significant effects on the breeding success of any species. We conclude that nesting-platforms constitute an important resource for forest raptors and that their longevity is sufficiently high to allow their reuse in multiple breeding attempts. PMID

  18. Interspecific nest parasitism by chukar on greater sage-grouse

    Science.gov (United States)

    Fearon, Michelle L.; Coates, Peter S.

    2014-01-01

    Nest parasitism occurs when a female bird lays eggs in the nest of another and the host incubates the eggs and may provide some form of parental care for the offspring (Lyon and Eadie 1991). Precocial birds (e.g., Galliformes and Anseriformes) are typically facultative nest parasites of both their own and other species (Lyon and Eadie 1991). This behavior increases a female’s reproductive success when she parasitizes other nests while simultaneously raising her own offspring. Both interspecific and conspecific nest parasitism have been well documented in several families of the order Galliformes, particularly the Phasianidae (Lyon and Eadie 1991, Geffen and Yom-Tov 2001, Krakauer and Kimball 2009). The Chukar (Alectoris chukar) has been widely introduced as a game bird to western North America from Eurasia and is now well established within the Great Basin from northeastern California east to Utah and north to Idaho and Oregon (Christensen 1996). Over much of this range the Chukar occurs with other phasianids, including the native Greater Sage-Grouse (Centrocercus urophasianus), within sagebrush (Artemisia spp.) steppe (Christensen 1996, Schroeder et al. 1999, Connelly et al. 2000). Chukar typically exploit a broader range of habitats than do sage-grouse, but both species use the same species of sagebrush and other shrubs for nesting cover (Christensen 1996, Schroeder et al. 1999). Chukar are known to parasitize nests of other individuals of their own species (Geffen and Yom-Tov 2001), but we are unaware of reported evidence that Chukar may parasitize nests of sage-grouse. Here we describe a case of a Chukar parasitizing a sage-grouse nest in the sagebrush steppe of western Nevada.

  19. Habitat characteristics of nesting areas and of predated nests in a Mediterranean population of the European pond turtle, Emys orbicularis galloitalica

    Directory of Open Access Journals (Sweden)

    Marco A.L. Zuffi

    2006-01-01

    Full Text Available one of the largest population of Emys orbicularis galloitalica of central Italy inhabits the canal system wet areas within a natural protected park. Features of nesting habitats, nest structure, and predation patterns of 209 nests of a large population of the European pond turtle are here presented and analysed. Nest sites were characterised by sunny bushy areas in strip habitat, digged along north-south oriented canals, on average with about 26% of the area covered by vegetation, less than one meter distant from 30 cm height bushes, at about 11 m from water and at about 13 m distance from wooded areas, 28 m away from a road. Principal Component and discriminant analyses were used on 20 selected variables in order to reduce the number of physical variables, and indicate that canal border, strip habitat, and canal orientation are grouping variables, that correctly classified 41.6%, 66.5%, and 100 % respectively of nest presence.

  20. Pyothorax induced by an intrathoracic foreign body in a miniature dachshund: Migration of a popsicle stick from the stomach.

    Science.gov (United States)

    Choi, Yi-Don; Han, Hyun-Jung

    2017-08-10

    A four-year-old dachshund presented with a two-week history of pyrexia, depression, and cough. Four months earlier, the owner observed the dog swallow a whole popsicle stick, but the animal showed no clinical signs at that time. Radiography, ultrasonography, and computed tomography confirmed an intrathoracic linear foreign body and pleural effusion in the right thorax. The pleural fluid was bloody and purulent, and contained inflammatory cells and Escherichia coli. The dog was diagnosed with pyothorax induced by a foreign body, and was treated successfully by surgical removal of the foreign body, partial lung lobectomy, thoracic lavage, and antibiotics. The foreign body was identified as a popsicle stick that the dog had eaten.