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Sample records for black queen cell

  1. Genetic Analysis and Phylogenetic Comparison of Black Queen Cell Virus Genotypes

    OpenAIRE

    2009-01-01

    Abstract Phylogenetic analysis of 22 Black queen cell virus (BQCV) genotypes collected from honeybee colonies in Poland, Austria and Hungary was performed on a partial helicase enzyme coding region (ORF1) and on a partial structural polypeptide coding region (ORF2). While the phylogeny based on the ORF2 region showed ? with the exception of one strain from Poland ? clustering of the genotypes corresponding to their geographic origin, the ORF1-based tree exhibited a completely diffe...

  2. [Symptomatic Black Queen Cell Virus infection of drone brood in Hessian apiaries].

    Science.gov (United States)

    Siede, Reinhold; Büchler, Ralph

    2003-01-01

    The Black Queen Cell Virus (BQCV) can affect brood of the honey bee (Apis mellifera). In general queen cells are endangered showing dark coloured cell walls as typical symptoms. Worker- and dronebrood can be infected by BQCV but normally without clinical symptoms. This paper describes for the first time a symptomatic BQCV-infection of diseased drone brood found on two bee yards in Hessen/Germany in 2001. The drone larvae were seriously damaged and some of them were dead. Samples of the affected brood were tested for BQCV by the PCR detection method. A BQCV specific nucleic acid fragment was found. The PCR product were sequenced and aligned with the relevant GenBank entry. At the nucleic acid level as well as at the deduced protein level the isolate showed a high similarity with the south african isolate noted in GenBank.

  3. Virion Structure of Black Queen Cell Virus, a Common Honeybee Pathogen

    Science.gov (United States)

    Spurny, Radovan; Přidal, Antonín; Pálková, Lenka; Kiem, Hoa Khanh Tran; de Miranda, Joachim R.

    2017-01-01

    ABSTRACT Viral diseases are a major threat to honeybee (Apis mellifera) populations worldwide and therefore an important factor in reliable crop pollination and food security. Black queen cell virus (BQCV) is the etiological agent of a fatal disease of honeybee queen larvae and pupae. The virus belongs to the genus Triatovirus from the family Dicistroviridae, which is part of the order Picornavirales. Here we present a crystal structure of BQCV determined to a resolution of 3.4 Å. The virion is formed by 60 copies of each of the major capsid proteins VP1, VP2, and VP3; however, there is no density corresponding to a 75-residue-long minor capsid protein VP4 encoded by the BQCV genome. We show that the VP4 subunits are present in the crystallized virions that are infectious. This aspect of the BQCV virion is similar to that of the previously characterized triatoma virus and supports the recent establishment of the separate genus Triatovirus within the family Dicistroviridae. The C terminus of VP1 and CD loops of capsid proteins VP1 and VP3 of BQCV form 34-Å-tall finger-like protrusions at the virion surface. The protrusions are larger than those of related dicistroviruses. IMPORTANCE The western honeybee is the most important pollinator of all, and it is required to sustain the agricultural production and biodiversity of wild flowering plants. However, honeybee populations worldwide are suffering from virus infections that cause colony losses. One of the most common, and least known, honeybee pathogens is black queen cell virus (BQCV), which at high titers causes queen larvae and pupae to turn black and die. Here we present the three-dimensional virion structure of BQCV, determined by X-ray crystallography. The structure of BQCV reveals large protrusions on the virion surface. Capsid protein VP1 of BQCV does not contain a hydrophobic pocket. Therefore, the BQCV virion structure provides evidence that capsid-binding antiviral compounds that can prevent the

  4. Coexistence of evolving bacteria stabilized by a shared Black Queen function.

    Science.gov (United States)

    Morris, J Jeffrey; Papoulis, Spiridon E; Lenski, Richard E

    2014-10-01

    The Black Queen Hypothesis (BQH) was originally proposed to explain the dependence of some marine bacteria on helper organisms for protection from hydrogen peroxide (HOOH). The BQH predicts that selection for the evolutionary loss of leaky functions from individuals can produce commensal or mutualistic interactions. We demonstrated the leakiness of HOOH detoxification by complementing a HOOH-sensitive Escherichia coli mutant with a plasmid-encoded HOOH-detoxifying enzyme, KatG, and then evolving populations founded by this strain in two environments. When HOOH was absent, plasmid-carrying cells were outcompeted by plasmid-free segregants, reflecting the high cost of KatG expression. However, plasmid-carrying and plasmid-free cells coexisted for at least 1200 generations in three replicate populations evolved in the presence of HOOH, although their relative proportions fluctuated as beneficial mutations arose in one type or the other. Evolved plasmid-bearing cells reduced the cost of plasmid carriage even as they increased the rate of HOOH removal relative to the ancestor. Meanwhile, plasmid-free cells remained dependent on HOOH detoxification by the plasmid-bearing cells. These results demonstrate that partitioning of a Black Queen function can enable the stable coexistence of very similar organisms, even in this most restrictive case where the two types are competing for a single resource.

  5. Proceedings of the Queen's-RMC Fuel Cell Research Centre fuel cell technology day

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The Queen's-RMC Fuel Cell Research Centre was formed to conduct research on polymer electrolyte membrane (PEM) and solid oxide (SOFC) fuel cells as well as fuel processing and hydrogen production and storage technologies. The centre focuses on the development of manufacturing methods, mathematical modelling, catalysis and reaction engineering, and computational thermodynamics. The fuel cell technology day provided a forum for research leaders from various institutions to discuss recent studies related to PEM and SOFC fuel cells. Issues related to materials and system degradation in fuel cells were discussed along with recent developments in the micro-engineering of SOFC cathodes. Commercialization plans for megawatt fuel cells were also discussed, and recent spectroscopy and voltammetry studies of PEM fuel cells were presented. A panel discussion was also held to determine research directions for the future. The technology day featured 7 presentations, of which 2 have been catalogued separately for inclusion in this database. tabs., figs.

  6. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io;

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....

  7. Characteristics of Honey Bee (Apis Mellifera Carnica, Pollman 1879 Queens Reared in Slovenian Commercial Breeding Stations

    Directory of Open Access Journals (Sweden)

    Gregorc Aleš

    2015-12-01

    Full Text Available In this three-year-trial study, we examined the quality of mated queens based on morphological and physiology traits. At each location, sister queen bees were reared each year from one Apis mellifera carnica breeder queen. Queens were also reared and mated in different locations. Altogether, we sampled and analysed 324 queens from 27 apiaries in 2006, 288 queens from 24 apiaries in 2008, and 276 queens from 23 apiaries in 2010. Nine queens from each apiary were sampled and dissected for morphological analyses and Nosema ceranae (N. ceranae spores, if present, were quantified. Three queens from each apiary were prepared and tested for four viruses: acute bee paralysis virus (ABPV, black queen cell virus (BQCV, deformed wing virus (DWV, and sacbrood virus (SBV. The highest average queen weight of 209.49 ± 9.82 mg was detected in 2008. The highest average ovary weight of 78.67 ± 11.86 mg was detected in 2010, and the highest number of ovarioles was 161.59 ± 8.70 in 2006. The average number of spermatozoa in queens ranged from 3.30 x 106 in 2006 to 5.23 x 106 in 2010. Nosema ceranae spores were found in queens sampled in 2008 and 2010. Viruses were discovered sporadically during the queen testing periods from 2006 - 2010. This study importantly demonstrates that queens from rearing stations require regular evaluation for morphological and physiological changes as well as for infection from harmful pathogens. These results could also be used in establishing relevant commercial standards for rearing quality queens.

  8. The Effects of Pesticides on Queen Rearing and Virus Titers in Honey Bees (Apis mellifera L.

    Directory of Open Access Journals (Sweden)

    Gloria DeGrandi-Hoffman

    2013-01-01

    Full Text Available The effects of sublethal pesticide exposure on queen emergence and virus titers were examined. Queen rearing colonies were fed pollen with chlorpyrifos (CPF alone (pollen-1 and with CPF and the fungicide Pristine® (pollen-2. Fewer queens emerged when larvae from open foraging (i.e., outside colonies were reared in colonies fed pollen-1 or 2 compared with when those larvae were reared in outside colonies. Larvae grafted from and reared in colonies fed pollen-2 had lower rates of queen emergence than pollen-1 or outside colonies. Deformed wing virus (DWV and black queen cell virus were found in nurse bees from colonies fed pollen-1 or 2 and in outside colonies. The viruses also were detected in queen larvae. However, we did not detect virus in emerged queens grafted from and reared in outside colonies. In contrast, DWV was found in all emerged queens grafted from colonies fed pollen-1 or 2 either reared in outside hives or those fed pollen-1 or 2. The results suggest that sublethal exposure of CPF alone but especially when Pristine® is added reduces queen emergence possibly due to compromised immunity in developing queens.

  9. Histology and ultrastructure of pericardial cells of Scaptotrigona postica Latreille (Hymenoptera, Apidae) in workers and queens of different ages.

    Science.gov (United States)

    Poiani, Silvana Beani; da Cruz-Landim, Carminda

    2007-01-01

    The paper presents a study of the pericardial cells of Scaptotrigona postica an eusocial Brazilian stingless bee. Light and electron microscopy was used in a comparative study on workers and queens of different ages, exerting different functions in the colony. The pericardial cells are found only in the pericardial sinus, mainly in groups around the dorsal vessel. Each cell is enclosed by the basal membrane and its peripheral region is characterized by folds of the plasma membrane, which form canals and loops. The points where the plasma membrane folds is frequently closed by diaphragms, that along with the basal lamina form a barrier to substances from hemolymph. Along the membrane limiting the canals and loops, an intense endocytic activity through coated vesicles takes place indicating a selective absorption of hemolymph components. In older individuals, workers or queens, the cells exhibit larger quantities of cytoplasm inclusions, heterogeneous vacuoles containing the final products of intracellular digestion, and autophagic vacuoles with concentric membranous structures. The pericardial cells general morphology is in accordance with the role in processing metabolites captured from hemolymph and storage of indigested residues.

  10. Black silicon solar cells with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by maskless reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Four different methods to obtain blackened bus-bar strings were compared with respect to reflectance, and two of these methods (i.e., oxidized copper and etched solder) were used to fabricate functional allblack solar 9-cell panels. The black bus-bars (e.......g., by oxidized copper) have a reflectance below 3% in the entire visible wavelength range. The combination of black silicon cells and blackened bus-bars results in aesthetic, all-black panels based on conventional, front-contacted solar cells without compromising efficiency....

  11. The Eight Queens Problem.

    Science.gov (United States)

    Olson, Alton T.

    1993-01-01

    Presents a series of solution methods to the Eight Queens Problem of placing eight queens on a chess board so that no one queen can capture another. Solution methods progress from empirical approaches to the use of computer algorithms. Geometric transformations are used to find other solutions. (MDH)

  12. Mitosis and cell death in the optic lobes of workers, queens and drones of the honey bee (Apis mellifera) during metamorphosis

    Indian Academy of Sciences (India)

    Thaisa Cristina Roat; Carminda Da Cruz Landim

    2010-09-01

    Colonies of the honey bee, Apis mellifera, consist of males and two female castes: workers and queens. The castes and males from A. mellifera have a distinct morphology, physiology and behaviour that correlate with their roles in the society and are characterized by some brain polymorphisms. Compound eyes are one of the characteristics that differ among the castes and sexes. A. mellifera is a holometabolous insect; therefore, the development of adult organs during metamorphosis, which will produce these differences, requires the precise coordination of three main programmed cellular processes: proliferation, differentiation and death. These processes take place simultaneously during pupation. Our purpose was to investigate cell division and death in the optic lobes (OL) of workers, queens and males during pupation to identify how the differences in the compound eyes in adults of these classes are achieved. The results showed that OL differentiation follows a similar pattern in the three classes of individuals studied, without structural differences in their development. The main non-structural differences involve cell division, mortality rates and timing. The results suggest a modelling of the brain during differentiation, which contributes to the specific functions of each individual class.

  13. Mitosis and cell death in the optic lobes of workers, queens and drones of the honey bee (Apis mellifera) during metamorphosis.

    Science.gov (United States)

    Roat, Thaisa Cristina; Landim, Carminda da Cruz

    2010-09-01

    Colonies of the honey bee, Apis mellifera, consist of males and two female castes: workers and queens. The castes and males from A. mellifera have a distinct morphology, physiology and behaviour that correlate with their roles in the society and are characterized by some brain polymorphisms. Compound eyes are one of the characteristics that differ among the castes and sexes. A. mellifera is a holometabolous insect; therefore, the development of adult organs during metamorphosis, which will produce these differences, requires the precise coordination of three main programmed cellular processes: proliferation, differentiation and death. These processes take place simultaneously during pupation. Our purpose was to investigate cell division and death in the optic lobes (OL) of workers, queens and males during pupation to identify how the differences in the compound eyes in adults of these classes are achieved. The results showed that OL differentiation follows a similar pattern in the three classes of individuals studied, without structural differences in their development. The main non-structural differences involve cell division, mortality rates and timing. The results suggest a modelling of the brain during differentiation, which contributes to the specific functions of each individual class.

  14. Sickle Cell Trait in Blacks Can Skew Diabetes Test Results

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_163463.html Sickle Cell Trait in Blacks Can Skew Diabetes Test Results ... less accurate in black people who have the sickle cell anemia trait, a new study says. The test ...

  15. 'Snow Queen' Animation

    Science.gov (United States)

    2008-01-01

    This animation consists of two close-up images of 'Snow Queen,' taken several days apart, by the Robotic Arm Camera (RAC) aboard NASA's Phoenix Mars Lander. Snow Queen is the informal name for a patch of bright-toned material underneath the lander. Thruster exhaust blew away surface soil covering Snow Queen when Phoenix landed on May 25, 2008, exposing this hard layer comprising several smooth rounded cavities beneath the lander. The RAC images show how Snow Queen visibly changed between June 15, 2008, the 21st Martian day, or sol, of the mission and July 9, 2008, the 44th sol. Cracks as long as 10 centimeters (about four inches) appeared. One such crack is visible at the left third and the upper third of the Sol 44 image. A seven millimeter (one-third inch) pebble or clod appears just above and slightly to the right of the crack in the Sol 44 image. Cracks also appear in the lower part of the left third of the image. Other pieces noticeably shift, and some smooth texture has subtly roughened. The Phoenix team carefully positioned and focused RAC the same way in both images. Each image is about 60 centimeters, or about two feet, wide. The object protruding in from the top on the right half of the images is Phoenix's thermal and electrical conductivity probe. Snow Queen and other ice exposed by Phoenix landing and trenching operations on northern polar Mars is the first time scientists have been able to monitor Martian ice at a place where temperatures are cold enough that the ice doesn't immediately sublimate, or vaporize, away. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  16. Bee Queen Breeding Methods - Review

    Directory of Open Access Journals (Sweden)

    Silvia Patruica

    2016-05-01

    Full Text Available The biological potential of a bee family is mainly generated by the biological value of the queen. Whether we grow queens widely or just for our own apiaries, we must consider the acquisition of high-quality biological material, and also the creation of optimal feeding and caring conditions, in order to obtain high genetic value queens. Queen breeding technology starts with the setting of hoeing families, nurse families, drone-breeding families – necessary for the pairing of young queens, and also of the families which will provide the bees used to populate the nuclei where the next queens will hatch. The complex of requirements for the breeding of good, high-production queens is sometimes hard to met, under the application of artificial methods. The selection of breeding method must rely on all these requirements and on the beekeeper’s level of training.

  17. Differences in mushroom bodies morphogenesis in workers, queens and drones of Apis mellifera: neuroblasts proliferation and death.

    Science.gov (United States)

    Roat, Thaisa Cristina; da Cruz Landim, Carminda

    2010-06-01

    Apis mellifera is an interesting model to neurobiological studies. It has a relatively small brain that commands the complex learning and memory tasks demanded by the social organization. An A. mellifera colony is made up of a queen, thousands of workers and a varying number of drones. The latter are males, whereas the former are the two female castes. These three phenotypes differ in morphology, physiology and behavior, correlated with their respective functions in the society. Such differences include the morphology and architecture of their brains. To understand the processes generating such polymorphic brains we characterized the cell division and cell death dynamics which underlie the morphogenesis of the mushroom bodies, through several methods suitable for evidence the time and place of occurrence. Cell death was detected in mushroom bodies of last larval instar and mainly in black-eyed pupae. Cell division was observed in mushroom bodies, primarily at the start of metamorphosis, exhibiting temporal differences among workers, queens and males.

  18. Queen signaling in social wasps

    DEFF Research Database (Denmark)

    van Zweden, Jelle Stijn; Bonckaert, Wim; Wenseleers, Tom;

    2014-01-01

    saxonica, queens emit reliable chemical cues of their true fertility and that these putative queen signals decrease as the colony develops and worker reproduction increases. Moreover, these putative pheromones of D. saxonica show significant conservation with those of Vespula vulgaris and other Vespinae...

  19. Alex McQueen : power

    Index Scriptorium Estoniae

    1998-01-01

    A. McQueeni moevälisest tegevusest. 'American Express' tellis temalt krediitkaardi kujunduse. 1998. a. suvest ajakirja 'Dazed & Confused' abitoimetaja. A. McQueen on lubanud olla Björki (Island) video kunstiline juht.

  20. Killing and replacing queen-laid eggs: low cost of worker policing in the honeybee.

    Science.gov (United States)

    Kärcher, Martin H; Ratnieks, Francis L W

    2014-07-01

    Worker honeybees, Apis mellifera, police each other's reproduction by killing worker-laid eggs. Previous experiments demonstrated that worker policing is effective, killing most (∼98%) worker-laid eggs. However, many queen-laid eggs were also killed (∼50%) suggesting that effective policing may have high costs. In these previous experiments, eggs were transferred using forceps into test cells, mostly into unrelated discriminator colonies. We measured both the survival of unmanipulated queen-laid eggs and the proportion of removal errors that were rectified by the queen laying a new egg. Across 2 days of the 3-day egg stage, only 9.6% of the queen-laid eggs in drone cells and 4.1% in worker cells were removed in error. When queen-laid eggs were removed from cells, 85% from drone cells and 61% from worker cells were replaced within 3 days. Worker policing in the honeybee has a high benefit to policing workers because workers are more related to the queen's sons (brothers, r = 0.25) than sister workers' sons (0.15). This study shows that worker policing also has a low cost in terms of the killing of queen-laid eggs, as only a small proportion of queen-laid eggs are killed, most of which are rapidly replaced.

  1. Prudent sperm use by leaf-cutter ant queens

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Baer, Boris; Dreier, Stéphanie Agnès Jeanine;

    2009-01-01

    In many species, females store sperm between copulation and egg fertilization, but the consequences of sperm storage and patterns of sperm use for female life history and reproductive success have not been investigated in great detail. In hymenopteran insect societies (ants, bees, wasps), reprodu......In many species, females store sperm between copulation and egg fertilization, but the consequences of sperm storage and patterns of sperm use for female life history and reproductive success have not been investigated in great detail. In hymenopteran insect societies (ants, bees, wasps......), reproduction is usually monopolized by one or relatively few queens, who mate only during a brief period early in life and store sperm for later use. The queens of some ants are particularly long-lived and have the potential to produce millions of offspring during their life. To do so, queens store many sperm...... cells, and this sperm must remain viable throughout the years of storage. Queens should also be under strong selection to use stored sperm prudently when fertilizing eggs. We used the leaf-cutter ant Atta colombica to investigate the dynamics of sperm use during egg fertilization. We show that queens...

  2. Neonicotinoid pesticides severely affect honey bee queens.

    Science.gov (United States)

    Williams, Geoffrey R; Troxler, Aline; Retschnig, Gina; Roth, Kaspar; Yañez, Orlando; Shutler, Dave; Neumann, Peter; Gauthier, Laurent

    2015-10-13

    Queen health is crucial to colony survival of social bees. Recently, queen failure has been proposed to be a major driver of managed honey bee colony losses, yet few data exist concerning effects of environmental stressors on queens. Here we demonstrate for the first time that exposure to field-realistic concentrations of neonicotinoid pesticides during development can severely affect queens of western honey bees (Apis mellifera). In pesticide-exposed queens, reproductive anatomy (ovaries) and physiology (spermathecal-stored sperm quality and quantity), rather than flight behaviour, were compromised and likely corresponded to reduced queen success (alive and producing worker offspring). This study highlights the detriments of neonicotinoids to queens of environmentally and economically important social bees, and further strengthens the need for stringent risk assessments to safeguard biodiversity and ecosystem services that are vulnerable to these substances.

  3. Genetic reincarnation of workers as queens in the Eastern honeybee Apis cerana.

    Science.gov (United States)

    Holmes, M J; Tan, K; Wang, Z; Oldroyd, B P; Beekman, M

    2015-01-01

    Thelytokous parthenogenesis, or the asexual production of female offspring, is rare in the animal kingdom, but relatively common in social Hymenoptera. However, in honeybees, it is only known to be ubiquitous in one subspecies of Apis mellifera, the Cape honeybee, A. mellifera capensis. Here we report the appearance of queen cells in two colonies of the Eastern honeybee Apis cerana that no longer contained a queen or queen-produced brood to rear queens from. A combination of microsatellite genotyping and the timing of the appearance of these individuals excluded the possibility that they had been laid by the original queen. Based on the genotypes of these individuals, thelytokous production by natal workers is the most parsimonious explanation for their existence. Thus, we present the first example of thelytoky in a honeybee outside A. mellifera. We discuss the evolutionary and ecological consequences of thelytoky in A. cerana, in particular the role thelytoky may play in the recent invasions by populations of this species.

  4. A distinct role of the queen in coordinated workload and soil distribution in eusocial naked mole-rats.

    Directory of Open Access Journals (Sweden)

    Nobuyuki Kutsukake

    Full Text Available We investigated how group members achieve collective decision-making, by considering individual intrinsic behavioural rules and behavioural mechanisms for maintaining social integration. Using a simulated burrow environment, we investigated the behavioural rules of coordinated workload for soil distribution in a eusocial mammal, the naked mole-rat (Heterocephalus glaber. We tested two predictions regarding a distinct role of the queen, a socially dominant individual in the caste system: the presence of a queen would increase the workload of other caste individuals, and the cues by a queen would affect the soil distribution. In experiment 1, we placed four individuals of various castes from the same colony into an experimental burrow. Workers exhibited the highest frequency of workload compared to other castes. The presence of a queen activated the workload by other individuals. Individuals showed a consistent workload in a particular direction so as to bias the soil distribution. These results suggest that individuals have a consensus on soil distribution and that the queen plays a distinct role. In experiment 2, we placed the odour of a queen in one of four cells and observed its effect on other individuals' workload and soil distribution. Relative to other cells, individuals frequently dug in the queen cell so the amount of soil in the queen cell decreased. These results suggest that queen odour is an important cue in coordinated workload and soil distribution in this species.

  5. Patterns of viral infection in honey bee queens

    DEFF Research Database (Denmark)

    Francis, Roy Mathew; Kryger, Per; Nielsen, Steen Lykke

    2013-01-01

    The well-being of a colony and replenishment of the workers depends on a healthy queen. Diseases in queens are seldom reported, and our knowledge on viral infection in queens is limited. In this study, 86 honey bee queens were collected from beekeepers in Denmark. All queens were tested separatel...

  6. Chronic Bee Paralysis Virus in Honeybee Queens

    DEFF Research Database (Denmark)

    Amiri, Esmaeil; Meixner, Marina; Büchler, Ralph

    2014-01-01

    Chronic bee paralysis virus (CBPV) is known as a disease of worker honey bees. To investigate pathogenesis of the CBPV on the queen, the sole reproductive individual in a colony, we conducted experiments regarding the susceptibility of queens to CBPV. Results from susceptibility experiment showed...... a similar disease progress in the queens compared to worker bees after infection. Infected queens exhibit symptoms by Day 6 post infection and virus levels reach 1011 copies per head. In a transmission experiment we showed that social interactions may affect the disease progression. Queens with forced...... contact to symptomatic worker bees acquired an overt infection with up to 1011 virus copies per head in six days. In contrast, queens in contact with symptomatic worker bees, but with a chance to receive food from healthy bees outside the cage appeared healthy. The virus loads did not exceed 107...

  7. Black Silicon formation using dry etching for solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Murias, D. [Instituto Nacional de Astrofisica, Optica y Electronica, INAOE, Puebla (Mexico); Reyes-Betanzo, C., E-mail: creyes@inaoep.mx [Instituto Nacional de Astrofisica, Optica y Electronica, INAOE, Puebla (Mexico); Moreno, M.; Torres, A.; Itzmoyotl, A. [Instituto Nacional de Astrofisica, Optica y Electronica, INAOE, Puebla (Mexico); Ambrosio, R.; Soriano, M. [Universidad Autonoma de Ciudad Juarez, Chihuahua (Mexico); Lucas, J. [Instituto Tecnologico de Tehuacan, Puebla (Mexico); Cabarrocas, P. Roca i [Laboratoire de Physique des Interfaces et des Couches Minces, Ecole Polytechnique, CNRS, Palaiseau (France)

    2012-09-20

    A study on the formation of Black Silicon on crystalline silicon surface using SF{sub 6}/O{sub 2} and SF{sub 6}/O{sub 2}/CH{sub 4} based plasmas in a reactive ion etching (RIE) system is presented. The effect of the RF power, chamber pressure, process time, gas flow rates, and gas mixtures on the texture of silicon surface has been analyzed. Completely Black Silicon surfaces containing pyramid like structures have been obtained, using an optimized mask-free plasma process. Moreover, the Black Silicon surfaces have demonstrated average values of 1% and 4% for specular and diffuse reflectance respectively, feature that is suitable for the fabrication of low cost solar cells.

  8. Individual Recognition in Ant Queens

    DEFF Research Database (Denmark)

    D'Ettorre, Patrizia; Heinze, Jürgen

    2005-01-01

    Personal relationships are the cornerstone of vertebrate societies, but insect societies are either too large for individual recognition, or their members were assumed to lack the necessary cognitive abilities 1 and 2 . This paradigm has been challenged by the recent discovery that paper wasps...... recognize each other's unique facial color patterns [3] . Individual recognition is advantageous when dominance hierarchies control the partitioning of work and reproduction 2 and 4 . Here, we show that unrelated founding queens of the ant Pachycondyla villosa use chemical cues to recognize each other...

  9. Sperm use economy of honeybee (Apis mellifera) queens

    DEFF Research Database (Denmark)

    Baer, Boris; Collins, Jason; Maalaps, Kristiina;

    2016-01-01

    the fecundity and longevity of queens and therefore colony fitness. We quantified the number of sperm that honeybee (Apis mellifera) queens use to fertilize eggs. We examined sperm use in naturally mated queens of different ages and in queens artificially inseminated with different volumes of semen. We found...

  10. Stimulating natural supersedure of honeybee queens, Apis mellifera

    NARCIS (Netherlands)

    Hendriksma, H.P.; Calis, J.N.M.; Boot, W.J.

    2004-01-01

    When a honeybee queen starts to fail, she is often superseded by a young queen that takes over reproduction inside the colony. Natural supersedure in winter leads to an unfertilised young queen and colony loss. To reduce these losses we tried to stimulate supersedure of queens earlier in the season.

  11. Comparing alternative methods for holding virgin honey bee queens for one week in mailing cages before mating.

    Directory of Open Access Journals (Sweden)

    Gianluigi Bigio

    Full Text Available In beekeeping, queen honey bees are often temporarily kept alive in cages. We determined the survival of newly-emerged virgin honey bee queens every day for seven days in an experiment that simultaneously investigated three factors: queen cage type (wooden three-hole or plastic, attendant workers (present or absent and food type (sugar candy, honey, or both. Ten queens were tested in each of the 12 combinations. Queens were reared using standard beekeeping methods (Doolittle/grafting and emerged from their cells into vials held in an incubator at 34C. All 12 combinations gave high survival (90 or 100% for three days but only one method (wooden cage, with attendants, honey gave 100% survival to day seven. Factors affecting queen survival were analysed. Across all combinations, attendant bees significantly increased survival (18% vs. 53%, p<0.001. In addition, there was an interaction between food type and cage type (p<0.001 with the honey and plastic cage combination giving reduced survival. An additional group of queens was reared and held for seven days using the best method, and then directly introduced using smoke into queenless nucleus colonies that had been dequeened five days previously. Acceptance was high (80%, 8/10 showing that this combination is also suitable for preparing queens for introduction into colonies. Having a simple method for keeping newly-emerged virgin queens alive in cages for one week and acceptable for introduction into queenless colonies will be useful in honey bee breeding. In particular, it facilitates the screening of many queens for genetic or phenotypic characteristics when only a small proportion meets the desired criteria. These can then be introduced into queenless hives for natural mating or insemination, both of which take place when queens are one week old.

  12. Comparing alternative methods for holding virgin honey bee queens for one week in mailing cages before mating.

    Science.gov (United States)

    Bigio, Gianluigi; Grüter, Christoph; Ratnieks, Francis L W

    2012-01-01

    In beekeeping, queen honey bees are often temporarily kept alive in cages. We determined the survival of newly-emerged virgin honey bee queens every day for seven days in an experiment that simultaneously investigated three factors: queen cage type (wooden three-hole or plastic), attendant workers (present or absent) and food type (sugar candy, honey, or both). Ten queens were tested in each of the 12 combinations. Queens were reared using standard beekeeping methods (Doolittle/grafting) and emerged from their cells into vials held in an incubator at 34C. All 12 combinations gave high survival (90 or 100%) for three days but only one method (wooden cage, with attendants, honey) gave 100% survival to day seven. Factors affecting queen survival were analysed. Across all combinations, attendant bees significantly increased survival (18% vs. 53%, p<0.001). In addition, there was an interaction between food type and cage type (p<0.001) with the honey and plastic cage combination giving reduced survival. An additional group of queens was reared and held for seven days using the best method, and then directly introduced using smoke into queenless nucleus colonies that had been dequeened five days previously. Acceptance was high (80%, 8/10) showing that this combination is also suitable for preparing queens for introduction into colonies. Having a simple method for keeping newly-emerged virgin queens alive in cages for one week and acceptable for introduction into queenless colonies will be useful in honey bee breeding. In particular, it facilitates the screening of many queens for genetic or phenotypic characteristics when only a small proportion meets the desired criteria. These can then be introduced into queenless hives for natural mating or insemination, both of which take place when queens are one week old.

  13. Glandular epithelium as a possible source of a fertility signal in Ectatomma tuberculatum (Hymenoptera: Formicidae) queens.

    Science.gov (United States)

    da Hora, Riviane Rodigues; Delabie, Jacques Hubert Charles; dos Santos, Carolina Gonçalves; Serrão, José Eduardo

    2010-04-19

    The wax layer covering the insect's cuticle plays an important protective role, as for example, uncontrolled water loss. In social insects, wax production is well-known in some bees that use it for nest building. Curiously, mated-fertile queens of the ant Ectatomma tuberculatum produce an uncommon extra-wax coat and, consequently queens (mated-fertile females) are matte due to such extra cuticular hydrocarbon (CHC) coat that covers the cuticle and masks the brightness of the queens' cuticle while gynes (virgin-infertile queens) are shiny. In this study, histological analysis showed differences in the epidermis between fertile (i.e., queens or gynes with highly ovarian activity) and infertile females (gynes or workers with non developed ovaries). In fertile females the epidermis is a single layer of cubic cells found in all body segments whereas in infertile females it is a thin layer of flattened cells. Ultrastructural features showed active secretory tissue from fertile females similar to the glandular epithelium of wax-producing bees (type I gland). Different hypotheses related to the functions of the glandular epithelium exclusive to the E. tuberculatum fertile queens are discussed.

  14. Vaginal clear cell carcinoma in a Japanese Black cow

    OpenAIRE

    Michishita, Masaki; HORI, Makito; NAKAHIRA, Rei; Takahashi, Kimimasa

    2016-01-01

    During artificial insemination of an 18-year-old female Japanese Black cow, a mass that was of a hen’s egg size was found in the vagina. On necropsy, the firm mass, measuring approximately 3.5 × 3.5 × 3.0 cm, was located at the superior region of the vagina. The cut surface of the mass was gray-white in color with occasional necrotic or hemorrhagic areas. Histologically, the mass was composed of tumor cells arranged in solid nests of various sizes with an occasional tubular structure separate...

  15. Queen's discovery lauded by top scientific journal

    CERN Multimedia

    McGrady, S

    2002-01-01

    A scientific breakthrough at Queen's University's Sudbury Neutrino Observatory has received major international recognition. The journal Science ranked the discovery that cracked the "neutrino problem" second, in the journal's top 10 scientific achievements of 2002 (1/2 page).

  16. ECONOMIC EFFICIENCY OF VARIOUS QUEEN BEES MAINTENANCE SYSTEMS

    Directory of Open Access Journals (Sweden)

    A POPESCU

    2003-10-01

    Full Text Available The modern queens maintenance systems are based on the use of artificial insemination, queens’ maintenance in the so called „queens bank” , in this way assuring an increased economic efficiency in beekeeping. This study aimed to compare the economic efficiency of the implementation of A.I. to various queen bees maintenance systems. Three alternatives have been taken into account: V1-a queen bee in a cage together with her bees, V2- a queen bank system and V3 – a queen bee in a nucleus. For each queen bee maintenance alternative have been evaluated the most important indicators such as: expenses, incomes, profit, number of marketable inseminated and selected queen bees, honey production, cost/queen, revenue/queen, profit/queen, profit rate. The most effective alternative was the queen bank system assuring 2,400 marketable queen bees and 20 kg honey delivered yearly, USD 12,442 incomes, USD 3,400 expenses, USD 9,042 profit, that is USD 3.77/queen bee and 265.72 % profit rate under the condition as A.I. costs are just USD 1,058, representing 31.1 % of total queen bees maintenance costs.

  17. Similarity in venom alkaloid chemistry of alate queens of imported fire ants: implication for hybridization between Solenopsis richteri and S. invicta in the Southern United States.

    Science.gov (United States)

    Chen, Li; Lu, Yong-Yue; Hu, Qiong-Bo; Fadamiro, Henry Y

    2012-04-01

    Both cis- and trans-2-methyl-6-undecylpiperidines, MC11P, have been previously reported as the major components of the venom of alate queens of the imported fire ants, Solenopsis richteri (black) and S. invicta (red). To identify the minor components of venom alkaloids from alate queens and compare the venom alkaloid chemistry of alate queen of their hybrid (S. richteri×S. invicta) with that of the two parental fire ant species (S. richteri and S. invicta), silica-gel short-column chromatography was utilized for separating cis-stereoisomers of venom alkaloids from trans-stereoisomers. GC/MS Analyses of venom-alkaloid chemistry of alate queens demonstrated that fewer alkaloid peaks were detected in the chromatograms of the alate queens compared to those of workers. Three new compounds, 7, 12, and 13, were detected as minor components in the venom of alate queens of all three fire ant species. Alate queens of hybrid fire ants showed cis- and trans-alkaloid patterns similar to those of the parental species. Similarity in venom-alkaloid chemistry of alate queens of S. richteri and S. invicta, and their hybrid may indicate their reproductive compatibility in the hybrid zone in southern United States, where all three species occur sympatrically.

  18. Parentage, reproductive skew and queen turnover in a multiple-queen ant analysed with microsatellites.

    Science.gov (United States)

    Bourke, A F; Green, H A; Bruford, M W

    1997-02-22

    We investigated the fine genetic structure of colonies of the ant, Leptothorax acervorum, to examine how queens share parentage (skew) in a social insect with multiple queens (polygyny). Overall, 494 individuals from eight polygynous field colonies were typed at up to seven microsatellite loci each. The first main finding was that surprisingly many sexual progeny (60% of young queens and 49% of young males) were not the offspring of the extant queens within their colonies. This implies that a high turnover (brief reproductive lifespan) of queens within colonies could be an important feature of polygyny. The second main result was that in most colonies relatedness among sexual progeny fell significantly below that expected among full siblings, proving that these progeny were produced by more than one singly-mated queen, but that skew in two colonies where the data permitted its calculation was moderate to high. However, relative to a German population, the study population is characterized by low queen-queen relatedness and low skew in female production, which is in line with the predictions of skew theory.

  19. Sickle Cell Trait Tied to Higher Kidney Failure Risk for Blacks

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_164005.html Sickle Cell Trait Tied to Higher Kidney Failure Risk for ... HealthDay News) -- Black people with a trait for sickle cell anemia appear to have double the risk of ...

  20. Queen Charlotte 2001 Earthquake Aftershock Sequence

    Science.gov (United States)

    Mulder, T.; Rogers, G. C.

    2012-12-01

    On Oct 12, 2001, an Mw=6.3 earthquake occurred off the Queen Charlotte Islands, BC. It was felt throughout Haida Gwaii (Queen Charlotte Islands) and the adjoining mainland. It generated a small tsunami recorded on Vancouver Island tide gauges. Moment tensor solutions show almost pure thrust faulting. There was a significant aftershock sequence associated with this event. Relocation of the catalogue aftershock sequence with respect to a key calibration event with various subsets of common stations show significant movement in the event locations. The aftershocks define an ~30 degree dipping fault plane.

  1. Balancing acts: drag queens, gender and faith.

    Science.gov (United States)

    Sullivan-Blum, Constance R

    2004-01-01

    While engaged in research on the same-sex marriage debate in mainline denominations, I interviewed 23 LGBT Christians, four of whom were drag queens. While it is not possible to generalize from such a small sample, the drag queens in this study insist on maintaining their identity as Christians despite the hegemonic discourse that renders faith and LGBT identities mutually exclusive. They developed innovative approaches to reconciling their gender and sexual identities with their spirituality. Their innovations are potentially liberating not just for them personally, but for LGBT people generally because they challenge Christianity's rigid dichotomies of gender and sexuality.

  2. Effects of insemination quantity on honey bee queen physiology.

    Directory of Open Access Journals (Sweden)

    Freddie-Jeanne Richard

    Full Text Available Mating has profound effects on the physiology and behavior of female insects, and in honey bee (Apis mellifera queens, these changes are permanent. Queens mate with multiple males during a brief period in their early adult lives, and shortly thereafter they initiate egg-laying. Furthermore, the pheromone profiles of mated queens differ from those of virgins, and these pheromones regulate many different aspects of worker behavior and colony organization. While it is clear that mating causes dramatic changes in queens, it is unclear if mating number has more subtle effects on queen physiology or queen-worker interactions; indeed, the effect of multiple matings on female insect physiology has not been broadly addressed. Because it is not possible to control the natural mating behavior of queens, we used instrumental insemination and compared queens inseminated with semen from either a single drone (single-drone inseminated, or SDI or 10 drones (multi-drone inseminated, or MDI. We used observation hives to monitor attraction of workers to SDI or MDI queens in colonies, and cage studies to monitor the attraction of workers to virgin, SDI, and MDI queen mandibular gland extracts (the main source of queen pheromone. The chemical profiles of the mandibular glands of virgin, SDI, and MDI queens were characterized using GC-MS. Finally, we measured brain expression levels in SDI and MDI queens of a gene associated with phototaxis in worker honey bees (Amfor. Here, we demonstrate for the first time that insemination quantity significantly affects mandibular gland chemical profiles, queen-worker interactions, and brain gene expression. Further research will be necessary to elucidate the mechanistic bases for these effects: insemination volume, sperm and seminal protein quantity, and genetic diversity of the sperm may all be important factors contributing to this profound change in honey bee queen physiology, queen behavior, and social interactions in the

  3. Effects of insemination quantity on honey bee queen physiology.

    Science.gov (United States)

    Richard, Freddie-Jeanne; Tarpy, David R; Grozinger, Christina M

    2007-10-03

    Mating has profound effects on the physiology and behavior of female insects, and in honey bee (Apis mellifera) queens, these changes are permanent. Queens mate with multiple males during a brief period in their early adult lives, and shortly thereafter they initiate egg-laying. Furthermore, the pheromone profiles of mated queens differ from those of virgins, and these pheromones regulate many different aspects of worker behavior and colony organization. While it is clear that mating causes dramatic changes in queens, it is unclear if mating number has more subtle effects on queen physiology or queen-worker interactions; indeed, the effect of multiple matings on female insect physiology has not been broadly addressed. Because it is not possible to control the natural mating behavior of queens, we used instrumental insemination and compared queens inseminated with semen from either a single drone (single-drone inseminated, or SDI) or 10 drones (multi-drone inseminated, or MDI). We used observation hives to monitor attraction of workers to SDI or MDI queens in colonies, and cage studies to monitor the attraction of workers to virgin, SDI, and MDI queen mandibular gland extracts (the main source of queen pheromone). The chemical profiles of the mandibular glands of virgin, SDI, and MDI queens were characterized using GC-MS. Finally, we measured brain expression levels in SDI and MDI queens of a gene associated with phototaxis in worker honey bees (Amfor). Here, we demonstrate for the first time that insemination quantity significantly affects mandibular gland chemical profiles, queen-worker interactions, and brain gene expression. Further research will be necessary to elucidate the mechanistic bases for these effects: insemination volume, sperm and seminal protein quantity, and genetic diversity of the sperm may all be important factors contributing to this profound change in honey bee queen physiology, queen behavior, and social interactions in the colony.

  4. The effect of queen and worker adoption on weaver ant (Oecophylla smaragdina) queen fecundity

    DEFF Research Database (Denmark)

    Offenberg, Joachim; Peng, Renkang; Nielsen, Mogens Gissel;

    2012-01-01

    Incipient ant colonies are often under fierce competition, making fast growth crucial for survival. To increase production, colonies can adopt multiple queens (pleometrosis), fuse with other colonies or rob brood from neighboring colonies. However, different adoption strategies might have differe...

  5. Black silicon solar cells with interdigitated back-contacts achieve 22.1% efficiency

    OpenAIRE

    Savin, Hele; Repo, Päivikki; Von Gastrow, Guillaume; Ortega, Pablo; Calle, Eric; Garín, Moises; Alcubilla, Ramon

    2015-01-01

    The nanostructuring of silicon surfaces—known as black silicon—is a promising approach to eliminate front-surface reflection in photovoltaic devices without the need for a conventional antireflection coating. This might lead to both an increase in efficiency and a reduction in the manufacturing costs of solar cells. However, all previous attempts to integrate black silicon into solar cells have resulted in cell efficiencies well below 20% due to the increased charge carrier recombination at t...

  6. Ant parasite queens revert to mating singly

    DEFF Research Database (Denmark)

    Sumner, Seirian; Hughes, William Owen Hamar; Pedersen, Jes Søe;

    2004-01-01

    A parasitic ant has abandoned the multiple mating habit of the queens of its related host. Multiple mating (polyandry) is widespread among animal groups, particularly insects 1 . But the factors that maintain it and underlie its evolution are hard to verify because benefits and costs are not easi...

  7. Use of non-conventional cell disruption method for extraction of proteins from black yeasts

    Directory of Open Access Journals (Sweden)

    Maja eLeitgeb

    2016-04-01

    Full Text Available The influence of pressure and treatment time on cells disruption of different black yeasts and on activities of extracted proteins using supercritical carbon dioxide process was studied. The cells of three different black yeasts Phaeotheca triangularis, Trimatostroma salinum and Wallemia ichthyophaga were exposed to supercritical carbon dioxide (SC CO2 by varying pressure at fixed temperature (35 °C. The black yeasts cell walls were disrupted and the content of the cells was spilled into the liquid medium. The impact of SC CO2 conditions on secretion of enzymes and proteins from black yeast cells suspension was studied. The residual activity of the enzymes cellulase, β-glucosidase, α-amylase and protease was studied by enzymatic assay. The viability of black yeast cells was determined by measuring the optical density of the cell suspension at 600 nm. The total protein concentration in the suspension was determined on UV-Vis spectrophotometer at 595 nm. The release of intracellular and extracellular products from black yeast cells was achieved. Also, the observation by an environmental scanning electron microscopy shows major morphological changes with SC CO2 treated cells. The advantages of the proposed method are in a simple use which is also possible for heat sensitive materials on one hand and on the other hand integration of the extraction of enzymes and their use in biocatalytical reactions.

  8. Surface lipids of queen-laid eggs do not regulate queen production in a fission-performing ant

    Science.gov (United States)

    Ruel, Camille; Lenoir, Alain; Cerdá, Xim; Boulay, Raphaël

    2013-01-01

    In animal societies, most collective and individual decision making depends on the presence of reproductive individuals. The efficient transmission of information among reproductive and non-reproductive individuals is therefore a determinant of colony organization. In social insects, the presence of a queen modulates multiple colonial activities. In many species, it negatively affects worker reproduction and the development of diploid larvae into future queens. The queen mostly signals her presence through pheromone emission, but the means by which these chemicals are distributed in the colony are still unclear. In several ant species, queen-laid eggs are the vehicle of the queen signal. The aim of this study was to investigate whether queen-laid eggs of the ant Aphaenogaster senilis possess queen-specific cuticular hydrocarbons and/or Dufour or poison gland compounds, and whether the presence of eggs inhibited larval development into queens. Our results show that the queen- and worker-laid eggs shared cuticular and Dufour hydrocarbons with the adults; however, their poison gland compounds were not similar. Queen-laid eggs had more dimethylalkanes and possessed a queen-specific mixture of cuticular hydrocarbons composed of 3,11 + 3,9 + 3,7-dimethylnonacosane, in higher proportions than did worker-laid eggs. Even though the queen-laid eggs were biochemically similar to the queen, their addition to experimentally queenless groups did not prevent the development of new queens. More studies are needed on the means by which queen ant pheromones are transmitted in the colony, and how these mechanisms correlates with life history traits.

  9. Queen volatiles as a modulator of Tetragonisca angustula drone behavior.

    Science.gov (United States)

    Fierro, Macario M; Cruz-López, Leopoldo; Sánchez, Daniel; Villanueva-Gutiérrez, Rogel; Vandame, Remy

    2011-11-01

    Tetragonisca angustula mating occurs during the virgin queen nuptial flight, usually in the presence of a drone congregation area (DCA). The presence of virgin queen pheromone is considered the trigger for DCA establishment, although this has not been demonstrated experimentally. We established meliponaries, in different habitats, with T. angustula virgin queens during the main drone reproduction period. Eight DCAs were observed in urban areas, and all established outside or near colonies containing at least one virgin queen. The accumulation of drones in the DCAs occurred from 08:00 to 18:00 h and over 3-35 days. The number of drones in DCAs ranged from 60 to 2,000. In field trials, drones were attracted to virgin queens and also, unexpectedly, to physogastric queens. Volatiles collected from both virgin and physogastric queens elicited strong electoantennogram (EAG) responses from drones. Virgin and physogastric queen volatiles were qualitatively similar, but quantitatively different, in chemical composition. The queen's abdomen was the principal source of these compounds. Isopropyl hexanoate (IPH), the most abundant compound in virgin queen volatiles and one of the most abundant in physogastric queen volatiles, was identified as one of the compounds that elicited EAG responses and was demonstrated to attract drones in a field test.

  10. Pregnancy in a unilaterally ovariohysterectomised queen.

    Science.gov (United States)

    Jurka, Piotr; Kacprzak, Kamil J; Degórska, Beata

    2015-04-01

    A 4-year-old female Russian Blue cat presented with signs of right-sided abdominal distension, anorexia and a mucoid vaginal discharge. On the basis of clinical and ultrasonographical findings a tentative diagnosis of uterine torsion was made. Exploratory coeliotomy revealed a 900º right uterine torsion along the longitudinal axis. Unilateral ovariohysterectomy was performed. Subsequently, the cat had two successful and uneventful pregnancies. To our knowledge this is the first case report of pregnancy in a unilaterally ovariohysterectomised queen.

  11. Black silicon solar cells with interdigitated back-contacts achieve 22.1% efficiency

    Science.gov (United States)

    Savin, Hele; Repo, Päivikki; von Gastrow, Guillaume; Ortega, Pablo; Calle, Eric; Garín, Moises; Alcubilla, Ramon

    2015-07-01

    The nanostructuring of silicon surfaces—known as black silicon—is a promising approach to eliminate front-surface reflection in photovoltaic devices without the need for a conventional antireflection coating. This might lead to both an increase in efficiency and a reduction in the manufacturing costs of solar cells. However, all previous attempts to integrate black silicon into solar cells have resulted in cell efficiencies well below 20% due to the increased charge carrier recombination at the nanostructured surface. Here, we show that a conformal alumina film can solve the issue of surface recombination in black silicon solar cells by providing excellent chemical and electrical passivation. We demonstrate that efficiencies above 22% can be reached, even in thick interdigitated back-contacted cells, where carrier transport is very sensitive to front surface passivation. This means that the surface recombination issue has truly been solved and black silicon solar cells have real potential for industrial production. Furthermore, we show that the use of black silicon can result in a 3% increase in daily energy production when compared with a reference cell with the same efficiency, due to its better angular acceptance.

  12. Black silicon solar cells with interdigitated back-contacts achieve 22.1% efficiency.

    Science.gov (United States)

    Savin, Hele; Repo, Päivikki; von Gastrow, Guillaume; Ortega, Pablo; Calle, Eric; Garín, Moises; Alcubilla, Ramon

    2015-07-01

    The nanostructuring of silicon surfaces--known as black silicon--is a promising approach to eliminate front-surface reflection in photovoltaic devices without the need for a conventional antireflection coating. This might lead to both an increase in efficiency and a reduction in the manufacturing costs of solar cells. However, all previous attempts to integrate black silicon into solar cells have resulted in cell efficiencies well below 20% due to the increased charge carrier recombination at the nanostructured surface. Here, we show that a conformal alumina film can solve the issue of surface recombination in black silicon solar cells by providing excellent chemical and electrical passivation. We demonstrate that efficiencies above 22% can be reached, even in thick interdigitated back-contacted cells, where carrier transport is very sensitive to front surface passivation. This means that the surface recombination issue has truly been solved and black silicon solar cells have real potential for industrial production. Furthermore, we show that the use of black silicon can result in a 3% increase in daily energy production when compared with a reference cell with the same efficiency, due to its better angular acceptance.

  13. Are queen ants inhibited by their own pheromone?

    DEFF Research Database (Denmark)

    Holman, L.; Leroy, C.; Jørgensen, Charlotte

    2013-01-01

    . Communication in social insects is predominantly chemical, and the mechanisms regulating processes such as reproductive division of labor are becoming increasingly well understood. Recently, a queen cuticular hydrocarbon (3-MeC31) that inhibits worker reproduction and aggression was isolated in the ant Lasius...... reproductives. The data suggest that queen pheromones have a multifaceted role in colony organization, allowing queens and workers alike to modulate their behavior and physiology in response to changes in colony composition. © The Author 2012....

  14. Matricide and queen sex allocation in a yellowjacket wasp

    Science.gov (United States)

    Loope, Kevin J.

    2016-08-01

    In many colonies of social insects, the workers compete with each other and with the queen over the production of the colony's males. In some species of social bees and wasps with annual societies, this intra-colony conflict even results in matricide—the killing of the colony's irreplaceable queen by a daughter worker. In colonies with low effective paternity and high worker-worker relatedness, workers value worker-laid males more than queen-laid males, and thus may benefit from queen killing. Workers gain by eliminating the queen because she is a competing source of male eggs and actively inhibits worker reproduction through policing. However, matricide may be costly to workers if it reduces the production of valuable new queens and workers. Here, I test a theoretical prediction regarding the timing of matricide in a wasp, Dolichovespula arenaria, recently shown to have facultative matricide based on intra-colony relatedness. Using analyses of collected, mature colonies and a surgical manipulation preventing queens from laying female eggs, I show that workers do not preferentially kill queens who are only producing male eggs. Instead, workers sometimes kill queens laying valuable females, suggesting a high cost of matricide. Although matricide is common and typically occurs only in low-paternity colonies, it seems that workers sometimes pay substantial costs in this expression of conflict over male parentage.

  15. The evolution of honest queen pheromones in insect societies

    DEFF Research Database (Denmark)

    van Zweden, Jelle Stijn

    2010-01-01

    Social insect workers are often capable of reproduction, but will not do so in the presence of a fertile queen. In large societies, queens are expected to produce a pheromone that honestly signals her dominance and/or fertility, to which workers respond by suppressing the development...... it is undermined by the fitness benefits of direct reproduction of workers at the individual level. A better explanation may be found in the idea that queen pheromones are difficult to produce for subordinate individuals, either because policing workers attack them, or because queen pheromones are intrinsically...

  16. Conservation of Queen Pheromones Across Two Species of Vespine Wasps.

    Science.gov (United States)

    Oi, Cintia A; Millar, Jocelyn G; van Zweden, Jelle S; Wenseleers, Tom

    2016-11-01

    Social insects are known for their reproductive division of labor between queens and workers, whereby queens lay the majority of the colony's eggs, and workers engage mostly in non-reproductive tasks. Queens produce pheromones that signal their presence and fertility to workers, which in turn generally remain sterile. Recently, it has been discovered that specific queen-characteristic cuticular hydrocarbons (CHCs) function as queen pheromones across multiple lineages of social insects. In the common wasp, Vespula vulgaris, several long-chain linear alkanes and 3-methylalkanes were shown to act as queen signals. Here, we describe similar bioassays with a related species of highly eusocial vespine wasp, the Saxon wasp, Dolichovespula saxonica. We show that a blend of queen-characteristic hydrocarbons that are structurally related to those of the common wasp inhibit worker reproduction, suggesting conservation of queen pheromones across social wasps. Overall, our results highlight the central importance of CHCs in chemical communication among social insects in general, and as conserved queen pheromones in these social wasps in particular.

  17. Queen succession through asexual reproduction in termites.

    Science.gov (United States)

    Matsuura, Kenji; Vargo, Edward L; Kawatsu, Kazutaka; Labadie, Paul E; Nakano, Hiroko; Yashiro, Toshihisa; Tsuji, Kazuki

    2009-03-27

    The evolution and maintenance of sexual reproduction may involve important tradeoffs because asexual reproduction can double an individual's contribution to the gene pool but reduces diversity. Moreover, in social insects the maintenance of genetic diversity among workers may be important for colony growth and survival. We identified a previously unknown termite breeding system in which both parthenogenesis and sexual reproduction are conditionally used. Queens produce their replacements asexually but use normal sexual reproduction to produce other colony members. These findings show how eusociality can lead to extraordinary reproductive systems and provide important insights into the advantages and disadvantages of sex.

  18. Viral diseases in honey bee queens

    DEFF Research Database (Denmark)

    Francis, Roy Mathew

    Honey bees are important insects for human welfare, due to pollination as well as honey production. Viral diseases strongly impact honey bee health, especially since the spread of varroa mites. This dissertation deals with the interactions between honey bees, viruses and varroa mites. A new tool...... was developed to diagnose three viruses in honey bees. Quantitative PCR was used to investigate the distribution of two popular viruses in five different tissues of 86 honey bee queens. Seasonal variation of viral infection in honey bee workers and varroa mites were determined by sampling 23 colonies under...

  19. Workers make the queens in melipona bees: identification of geraniol as a caste determining compound from labial glands of nurse bees.

    Science.gov (United States)

    Jarau, Stefan; van Veen, Johan W; Twele, Robert; Reichle, Christian; Gonzales, Eduardo Herrera; Aguilar, Ingrid; Francke, Wittko; Ayasse, Manfred

    2010-06-01

    Reproductive division of labor in advanced eusocial honey bees and stingless bees is based on the ability of totipotent female larvae to develop into either workers or queens. In nearly all species, caste is determined by larval nutrition. However, the mechanism that triggers queen development in Melipona bees is still unresolved. Several hypotheses have been proposed, ranging from the proximate (a genetic determination of caste development) to the ultimate (a model in which larvae have complete control over their own caste fate). Here, we showed that the addition of geraniol, the main compound in labial gland secretions of nurse workers, to the larval food significantly increases the number of larvae that develop into queens. Interestingly, the proportion of queens in treated brood exactly matched the value (25%) predicted by the two-locus, two-allele model of genetic queen determination, in which only females that are heterozygous at both loci are capable of developing into queens. We conclude that labial gland secretions, added to the food of some cells by nurse bees, trigger queen development, provided that the larvae are genetically predisposed towards this developmental pathway. In Melipona beecheii, geraniol acts as a primer pheromone representing the first caste determination substance identified to date.

  20. Questionnaire-based survey of parturition in the queen

    NARCIS (Netherlands)

    Musters, J.; de Gier, J.; Kooistra, H.S.; Okkens, A.C.

    2011-01-01

    The lack of scientific data concerning whether parturition in the queen proceeds normally or not may prevent veterinarians and cat owners from recognizing parturition problems in time. A questionnaire-based study of parturition in 197 queens was performed to determine several parameters of parturiti

  1. Sperm use economy of honeybee (Apis mellifera) queens

    DEFF Research Database (Denmark)

    Baer, Boris; Collins, Jason; Maalaps, Kristiina

    2016-01-01

    The queens of eusocial ants, bees, and wasps only mate during a very brief period early in life to acquire and store a lifetime supply of sperm. As sperm cannot be replenished, queens have to be highly economic when using stored sperm to fertilize eggs, especially in species with large and long-l...

  2. Effects of queen ages on Varroa (Varroa destructor infestation level in honey bee (Apis mellifera caucasica colonies and colony performance

    Directory of Open Access Journals (Sweden)

    Duran Özkök

    2010-01-01

    Full Text Available This study was conducted to determine the effects of queen age on varroa population levels in hives and performance of honey bee (A. mellifera caucasica colonies. Levels of varroa infestation and performances of the colonies which had 0, 1- and 2-year-old queens were compared in mild climate conditions. Varroa numbers on adults and drone brood, number of frames covered with bees and brood areas were determined every month between 10 May and 10 October 2004. Overall average (± S.E. % infestation levels of varroa were found to be 5.96 ± 1.42, 11.58 ± 1.46 and 15.87 ± 1.39% on adult bees and 21.55 ± 1.43, 31.96 ± 1.44 and 37.55 ± 1.45% in drone brood cells for 0, 1- and 2-year-old queen colonies, respectively. The colonies which had 0, 1- and 2-year-old queens produced 2673.58 ± 39.69, 2711.75 ± 39.68, and 1815.08 ± 39.70 cm2 overall average (± S.E. sealed brood and 10.35 ± 0.24, 10.43 ± 0.26 and 7.51 ± 0.21 numbers of frame adult bees, respectively. Honey harvested from 0, 1- and 2-year-old queen colonies averaged 21.60 ± 5.25, 22.20 ± 6.55, and 14.70 ± 2.50 kg/colony, respectively. The colonies headed by young queens had a lower level of varroa infestation, a greater brood area, longer worker bee population and greater honey yield in comparison to colonies headed by old queens.

  3. The evolution of queen pheromones in the ant genus Lasius.

    Science.gov (United States)

    Holman, L; Lanfear, R; d'Ettorre, P

    2013-07-01

    Queen pheromones are among the most important chemical messages regulating insect societies yet they remain largely undiscovered, hindering research into interesting proximate and ultimate questions. Identifying queen pheromones in multiple species would give new insight into the selective pressures and evolutionary constraints acting on these ubiquitous signals. Here, we present experimental and comparative evidence that 3-methylalkanes, hydrocarbons present on the queen's cuticle, are a queen pheromone throughout the ant genus Lasius. Interspecific variation in the chemical profile is consistent with 3-methylalkanes evolving more slowly than other types of hydrocarbons, perhaps due to differential selection or evolutionary constraints. We argue that the sensory ecology of the worker response imposes strong stabilizing selection on queen pheromones relative to other hydrocarbons. 3-Methylalkanes are also strongly physiologically and genetically coupled with fecundity in at least one Lasius species, which may translate into evolutionary constraints. Our results highlight how honest signalling could minimize evolutionary conflict over reproduction, promoting the evolution and maintenance of eusociality.

  4. Elevated peripheral blood mononuclear cell-derived superoxide production in healthy young black men.

    Science.gov (United States)

    Deo, Shekhar H; Holwerda, Seth W; Keller, David M; Fadel, Paul J

    2015-03-01

    Several studies have demonstrated that blacks exhibit elevations in systemic oxidative stress. However, the source(s) and mechanism(s) contributing to the elevation in oxidative stress remain unclear. Given that peripheral blood mononuclear cells (PBMCs) can be a major source of NADPH oxidase-derived superoxide production, we tested the hypothesis that young black men demonstrate greater superoxide production and NADPH oxidase expression in PBMCs compared with whites. PBMCs were freshly isolated from whole blood in young normotensive black (n = 18) and white (n = 16) men. Intracellular superoxide production in PBMCs was measured using dihydroethidium fluorescence, protein expression of NADPH oxidase subunits, gp91(phox) (membranous) and p47(phox) (cytosolic) in PBMCs were assessed using Western blot analysis, and plasma protein carbonyls were measured as a marker of systemic oxidative stress. Black men showed elevated intracellular superoxide production (4.3 ± 0.5 vs. 2.0 ± 0.6 relative fluorescence units; black men vs. white men, P superoxide production or NADPH oxidase subunit protein expression. These findings indicate that black men exhibit greater resting PBMC-derived superoxide production and an upregulation of the NADPH oxidase pathway with a possible contribution to increases in systemic oxidative stress.

  5. Carbon black nanoparticles and vascular dysfunction in cultured endothelial cells and artery segments

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Mikkelsen, Lone; Folkmann, Janne K;

    2012-01-01

    Exposure to small size particulates is regarded as a risk factor for cardiovascular disease. We investigated effects of exposure to nanosized carbon black (CB) in human umbilical vein endothelial cells (HUVECs) and segments of arteries from rodents. The CB exposure was associated with increased...

  6. Visceral mast cell tumor in a captive black jaguar (Panthera onca).

    Science.gov (United States)

    de Castro, Márcio Botelho; Werther, Karin; Godoy, Guilherme Sellera; Borges, Vivian Palmeira; Alessi, Antonio Carlos

    2003-03-01

    Little is known about neoplasia in the jaguar (Panthera onca), the largest American feline. A captive black jaguar was diagnosed at necropsy with a mastocytic form of visceral mast cell tumor similar to that which occurs in domestic cats. This animal had no previous clinical disease and died during anesthesia for a routine dental treatment.

  7. Sperm use economy of honeybee (Apis mellifera) queens

    DEFF Research Database (Denmark)

    Baer, Boris; Collins, Jason; Maalaps, Kristiina;

    2016-01-01

    the fecundity and longevity of queens and therefore colony fitness. We quantified the number of sperm that honeybee (Apis mellifera) queens use to fertilize eggs. We examined sperm use in naturally mated queens of different ages and in queens artificially inseminated with different volumes of semen. We found...

  8. Prudent sperm use by leaf-cutter ant queens

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Baer, Boris; Dreier, Stéphanie Agnès Jeanine

    2009-01-01

    In many species, females store sperm between copulation and egg fertilization, but the consequences of sperm storage and patterns of sperm use for female life history and reproductive success have not been investigated in great detail. In hymenopteran insect societies (ants, bees, wasps......), reproduction is usually monopolized by one or relatively few queens, who mate only during a brief period early in life and store sperm for later use. The queens of some ants are particularly long-lived and have the potential to produce millions of offspring during their life. To do so, queens store many sperm...

  9. Surface passivation of efficient nanotextured black silicon solar cells using thermal atomic layer deposition.

    Science.gov (United States)

    Wang, Wei-Cheng; Lin, Che-Wei; Chen, Hsin-Jui; Chang, Che-Wei; Huang, Jhih-Jie; Yang, Ming-Jui; Tjahjono, Budi; Huang, Jian-Jia; Hsu, Wen-Ching; Chen, Miin-Jang

    2013-10-09

    Efficient nanotextured black silicon solar cells passivated by an Al2O3 layer are demonstrated. The broadband antireflection of the nanotextured black silicon solar cells was provided by fabricating vertically aligned silicon nanowire (SiNW) arrays on the n(+) emitter. A highly conformal Al2O3 layer was deposited upon the SiNW arrays by the thermal atomic layer deposition (ALD) based on the multiple pulses scheme. The nanotextured black silicon wafer covered with the Al2O3 layer exhibited a low total reflectance of ∼1.5% in a broad spectrum from 400 to 800 nm. The Al2O3 passivation layer also contributes to the suppressed surface recombination, which was explored in terms of the chemical and field-effect passivation effects. An 8% increment of short-circuit current density and 10.3% enhancement of efficiency were achieved due to the ALD Al2O3 surface passivation and forming gas annealing. A high efficiency up to 18.2% was realized in the ALD Al2O3-passivated nanotextured black silicon solar cells.

  10. Queen Size Variation in the Ponerine Ant Ponera coarctata (Hymenoptera: Formicidae

    Directory of Open Access Journals (Sweden)

    J. Liebig

    1995-01-01

    Full Text Available Queens of Ponera coarctata show a pronounced variation in size as measured by ommatidia number and Weber's alitrunk length. Isometric size variation and the normal distribution of size categories indicate that, despite these differences, only one queen morph exists. Queen size varies less within colonies than between colonies, and thus appears to be colony specific. Ovary length apparently varies with queen size. Similar size variations as in queens also occured in males, but not in workers.

  11. Recovery of Queen Conch in the U. S. Virgin Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The queen conch is an important cultural component and an extremely valuable coral reef fishery resource throughout the Caribbean, historically second only to the...

  12. Radar detection of drones responding to honeybee queen pheromone.

    Science.gov (United States)

    Loper, G M; Wolf, W W; Taylor, O R

    1993-09-01

    The response of honey bee (Apis mellifera L.) drones to queen pheromone(s) (either natural from a mated queen, or synthetic from a lure) was recorded using an X-band, ground-based radar. The distribution of drones (insect targets on the radar screen) changed from a scattered distribution to a line concentration (downwind) when the pheromone was released. Displacement within the line concentration was toward the pheromone. This response was seen as far as 800±15 m downwind from a lure with 10 mg of synthetic 9-oxodec-trans-2-enoic acid (9-ODA) and as far as 420±15 m from a mated queen. These studies demonstrate that queen pheromone can be detected by drones at much greater distances than previously believed and illustrate how X-band radar may be used to establish the distances at which insects of similar or larger size respond to pheromones.

  13. Terminal investment: individual reproduction of ant queens increases with age.

    Directory of Open Access Journals (Sweden)

    Jürgen Heinze

    Full Text Available The pattern of age-specific fecundity is a key component of the life history of organisms and shapes their ecology and evolution. In numerous animals, including humans, reproductive performance decreases with age. Here, we demonstrate that some social insect queens exhibit the opposite pattern. Egg laying rates of Cardiocondyla obscurior ant queens increased with age until death, even when the number of workers caring for them was kept constant. Cardiocondyla, and probably also other ants, therefore resemble the few select organisms with similar age-specific reproductive investment, such as corals, sturgeons, or box turtles (e.g., [1], but they differ in being more short-lived and lacking individual, though not social, indeterminate growth. Furthermore, in contrast to most other organisms, in which average life span declines with increasing reproductive effort, queens with high egg laying rates survived as long as less fecund queens.

  14. Apiology: royal secrets in the queen's fat body.

    Science.gov (United States)

    Yamanaka, Naoki; O'Connor, Michael B

    2011-07-12

    Royalactin, a component of royal jelly, induces queen differentiation in honeybees. Surprisingly, royalactin has a similar effect on growth in fruit flies, highlighting many unexpected features of growth regulation by the insect fat tissue.

  15. Viruses associated with ovarian degeneration in Apis mellifera L. queens.

    Directory of Open Access Journals (Sweden)

    Laurent Gauthier

    Full Text Available Queen fecundity is a critical issue for the health of honeybee (Apis mellifera L. colonies, as she is the only reproductive female in the colony and responsible for the constant renewal of the worker bee population. Any factor affecting the queen's fecundity will stagnate colony development, increasing its susceptibility to opportunistic pathogens. We discovered a pathology affecting the ovaries, characterized by a yellow discoloration concentrated in the apex of the ovaries resulting from degenerative lesions in the follicles. In extreme cases, marked by intense discoloration, the majority of the ovarioles were affected and these cases were universally associated with egg-laying deficiencies in the queens. Microscopic examination of the degenerated follicles showed extensive paracrystal lattices of 30 nm icosahedral viral particles. A cDNA library from degenerated ovaries contained a high frequency of deformed wing virus (DWV and Varroa destructor virus 1 (VDV-1 sequences, two common and closely related honeybee Iflaviruses. These could also be identified by in situ hybridization in various parts of the ovary. A large-scale survey for 10 distinct honeybee viruses showed that DWV and VDV-1 were by far the most prevalent honeybee viruses in queen populations, with distinctly higher prevalence in mated queens (100% and 67%, respectively for DWV and VDV-1 than in virgin queens (37% and 0%, respectively. Since very high viral titres could be recorded in the ovaries and abdomens of both functional and deficient queens, no significant correlation could be made between viral titre and ovarian degeneration or egg-laying deficiency among the wider population of queens. Although our data suggest that DWV and VDV-1 have a role in extreme cases of ovarian degeneration, infection of the ovaries by these viruses does not necessarily result in ovarian degeneration, even at high titres, and additional factors are likely to be involved in this pathology.

  16. Chaotic Red Queen coevolution in three-species food chains

    Science.gov (United States)

    Dercole, Fabio; Ferriere, Regis; Rinaldi, Sergio

    2010-01-01

    Coevolution between two antagonistic species follows the so-called ‘Red Queen dynamics’ when reciprocal selection results in an endless series of adaptation by one species and counteradaptation by the other. Red Queen dynamics are ‘genetically driven’ when selective sweeps involving new beneficial mutations result in perpetual oscillations of the coevolving traits on the slow evolutionary time scale. Mathematical models have shown that a prey and a predator can coevolve along a genetically driven Red Queen cycle. We found that embedding the prey–predator interaction into a three-species food chain that includes a coevolving superpredator often turns the genetically driven Red Queen cycle into chaos. A key condition is that the prey evolves fast enough. Red Queen chaos implies that the direction and strength of selection are intrinsically unpredictable beyond a short evolutionary time, with greatest evolutionary unpredictability in the superpredator. We hypothesize that genetically driven Red Queen chaos could explain why many natural populations are poised at the edge of ecological chaos. Over space, genetically driven chaos is expected to cause the evolutionary divergence of local populations, even under homogenizing environmental fluctuations, and thus to promote genetic diversity among ecological communities over long evolutionary time. PMID:20356888

  17. Influence of black silicon surfaces on the performance of back-contacted back silicon heterojunction solar cells.

    Science.gov (United States)

    Ziegler, Johannes; Haschke, Jan; Käsebier, Thomas; Korte, Lars; Sprafke, Alexander N; Wehrspohn, Ralf B

    2014-10-20

    The influence of different black silicon (b-Si) front side textures prepared by inductively coupled reactive ion etching (ICP-RIE) on the performance of back-contacted back silicon heterojunction (BCB-SHJ) solar cells is investigated in detail regarding their optical performance, black silicon surface passivation and internal quantum efficiency. Under optimized conditions the effective minority carrier lifetime measured on black silicon surfaces passivated with Al(2)O(3) can be higher than lifetimes measured for the SiO(2)/SiN(x) passivation stack used in the reference cells with standard KOH textures. However, to outperform the electrical current of silicon back-contact cells, the black silicon back-contact cell process needs to be optimized with aspect to chemical and thermal stability of the used dielectric layer combination on the cell.

  18. Characterisation of cell wall polysaccharides in bilberries and black currants

    NARCIS (Netherlands)

    Hilz, H.

    2007-01-01

    During berry juice production, polysaccharides are released from the cell walls and cause thickening and high viscosity when the berries are mashed. Consequences are a low juice yield and a poor colour. This can be prevented by the use of enzymes that degrade these polysaccharides. To use these enzy

  19. Primary sex ratio adjustment by ant queens in response to local mate competition

    DEFF Research Database (Denmark)

    de Menten, Ludivine; Cremer, Sylvia; Heinze, Jürgen;

    2005-01-01

    of London, Series B, 269, 417-422) showed that colonies responded to increasing queen number by producing a less female-biased sex ratio, as predicted by LMC theory. However, the proximate mechanisms responsible for this variation in the sex ratio could not be determined because the study was restricted...... to adult sex ratios. With LMC, the primary sex ratio (proportion of haploid eggs laid by the queen) is expected to be female biased, which lowers the conflict between queens and workers over sex allocation. We compared the primary sex ratios laid by queens in monogynous and in polygynous experimental...... colonies of C. obscurior. The proportion of haploid eggs laid by queens was significantly lower in single-queen than in multiple-queen colonies. Furthermore, queens rapidly adjusted their primary sex ratios to changes in colony queen number. This is the first report of an adaptive adjustment of the primary...

  20. Survey of the Health Status of Some Honey Bee Queens in Italy

    Directory of Open Access Journals (Sweden)

    Porporato Marco

    2015-12-01

    Full Text Available While observing: non-acceptance, frequent replacements, and reduced performance in honey bee (Apis mellifera ligustica queens, we were induced to analyse a certain number of queens to detect the causes. For this purpose, 99 newly mated queens were bought from 20 Italian queen breeders. In addition, 109 older or at-the-end-of-their-career queens, that showed poor productivity, were collected from honey production hives throughout Italy. All the queens were dissected to check the status of their reproductive system and/or the presence of various anomalies and diseases.

  1. Black hairy tongue associated with allo peripheral blood hematopoietic stem cell transplantation

    Institute of Scientific and Technical Information of China (English)

    LUO Yi; ZOU Ping; LI Qiu-bai; YOU Yong

    2010-01-01

    @@ Tongue lesions resulting from mucositis are a frequent complication of high-dose chemotherapy and irradiation. They are very common in patients with hematopoietic stem cell transplantation, and tongue lesions due to other causes have also been reported. Black hairy tongue (BHT) is a special tongue lesion, not rare in the population with tobacco abuse, but so far it has not been reported after allo peripheral blood hematopoietic stem cell transplantation (allo-PBHST). Here we presented a patient who developed BHT after allo-PBHST and discussed the factors that may cause this condition.

  2. Multiple pigment cell types contribute to the black, blue, and orange ornaments of male guppies (Poecilia reticulata).

    Science.gov (United States)

    Kottler, Verena A; Koch, Iris; Flötenmeyer, Matthias; Hashimoto, Hisashi; Weigel, Detlef; Dreyer, Christine

    2014-01-01

    The fitness of male guppies (Poecilia reticulata) highly depends on the size and number of their black, blue, and orange ornaments. Recently, progress has been made regarding the genetic mechanisms underlying male guppy pigment pattern formation, but we still know little about the pigment cell organization within these ornaments. Here, we investigate the pigment cell distribution within the black, blue, and orange trunk spots and selected fin color patterns of guppy males from three genetically divergent strains using transmission electron microscopy. We identified three types of pigment cells and found that at least two of these contribute to each color trait. Further, two pigment cell layers, one in the dermis and the other in the hypodermis, contribute to each trunk spot. The pigment cell organization within the black and orange trunk spots was similar between strains. The presence of iridophores in each of the investigated color traits is consistent with a key role for this pigment cell type in guppy color pattern formation.

  3. Mating with stressed males increases the fitness of ant queens.

    Directory of Open Access Journals (Sweden)

    Alexandra Schrempf

    Full Text Available BACKGROUND: According to sexual conflict theory, males can increase their own fitness by transferring substances during copulation that increase the short-term fecundity of their mating partners at the cost of the future life expectancy and re-mating capability of the latter. In contrast, sexual cooperation is expected in social insects. Mating indeed positively affects life span and fecundity of young queens of the male-polymorphic ant Cardiocondyla obscurior, even though males neither provide nuptial gifts nor any other care but leave their mates immediately after copulation and die shortly thereafter. PRINCIPAL FINDINGS: Here, we show that mating with winged disperser males has a significantly stronger impact on life span and reproductive success of young queens of C. obscurior than mating with wingless fighter males. CONCLUSIONS: Winged males are reared mostly under stressful environmental conditions, which force young queens to disperse and found their own societies independently. In contrast, queens that mate with wingless males under favourable conditions usually start reproducing in the safety of the established maternal nest. Our study suggests that males of C. obscurior have evolved mechanisms to posthumously assist young queens during colony founding under adverse ecological conditions.

  4. Human lung epithelial cell A549 proteome data after treatment with titanium dioxide and carbon black.

    Science.gov (United States)

    Vuong, Ngoc Q; Goegan, Patrick; Mohottalage, Susantha; Breznan, Dalibor; Ariganello, Marianne; Williams, Andrew; Elisma, Fred; Karthikeyan, Subramanian; Vincent, Renaud; Kumarathasan, Premkumari

    2016-09-01

    Here, we have described the dataset relevant to the A549 cellular proteome changes after exposure to either titanium dioxide or carbon black particles as compared to the non-exposed controls, "Proteomic changes in human lung epithelial cells (A549) in response to carbon black and titanium dioxide exposures" (Vuong et al., 2016) [1]. Detailed methodologies on the separation of cellular proteins by 2D-GE and the subsequent mass spectrometry analyses using MALDI-TOF-TOF-MS are documented. Particle exposure-specific protein expression changes were measured via 2D-GE spot volume analysis. Protein identification was done by querying mass spectrometry data against SwissProt and RefSeq protein databases using Mascot search engine. Two-way ANOVA analysis data provided information on statistically significant A549 protein expression changes associated with particle exposures.

  5. Human lung epithelial cell A549 proteome data after treatment with titanium dioxide and carbon black

    Directory of Open Access Journals (Sweden)

    Ngoc Q. Vuong

    2016-09-01

    Full Text Available Here, we have described the dataset relevant to the A549 cellular proteome changes after exposure to either titanium dioxide or carbon black particles as compared to the non-exposed controls, “Proteomic changes in human lung epithelial cells (A549 in response to carbon black and titanium dioxide exposures” (Vuong et al., 2016 [1]. Detailed methodologies on the separation of cellular proteins by 2D-GE and the subsequent mass spectrometry analyses using MALDI-TOF-TOF-MS are documented. Particle exposure-specific protein expression changes were measured via 2D-GE spot volume analysis. Protein identification was done by querying mass spectrometry data against SwissProt and RefSeq protein databases using Mascot search engine. Two-way ANOVA analysis data provided information on statistically significant A549 protein expression changes associated with particle exposures.

  6. Vitellogenin content in fat body and ovary homogenates of workers and queens of Melipona quadrifasciata anthidioides during vitellogenesis

    Institute of Scientific and Technical Information of China (English)

    Vagner Tadeu Paes de Oliveira; Bruno Berger; Carminda da Cruz-Landim; Zilá Luz PaulinoSim(o)es

    2012-01-01

    Vitellogenin (Vg) is an egg yolk protein that is produced primarily in the fat body of most female insects.In the advanced social structure of eusocial honeybees,the presence of the queen inhibits egg maturation in the workers' ovaries.However in the stingless bee Melipona quadrifasciata,the workers always develop ovaries and lay a certain amount of eggs while provisioning the brood cells with larval food during what is known as the worker nurse phase.The present work is a comparative study of the presence of Vg in homogenates of the fat bodies and ovaries of the nurse workers,and the virgin and physogastric queens ofM.quadrifasciata.The presence of Vg was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting using Apis mellifera anti-egg antibody.Vg was not detected in the fat bodies or ovaries of the workers,but it was found in the ovaries of virgin and physogastric queens and in the fat body ofphysogastric queens.The results are discussed,taking into account the reproductive state of the individuals and the other possible roles of Vg,such as a storage protein for metoabolism of other organs.

  7. Social context predicts recognition systems in ant queens

    DEFF Research Database (Denmark)

    Dreier, Stéphanie Agnès Jeanine; d'Ettorre, Patrizia

    2009-01-01

    Recognition of group-members is a key feature of sociality. Ants use chemical communication to discriminate nestmates from intruders, enhancing kin cooperation and preventing parasitism. The recognition code is embedded in their cuticular chemical profile, which typically varies between colonies...... recognition does not occur when co-founding queens do not establish dominance hierarchies. Indeed, L. niger queens show a similar level of aggression towards both co-foundresses and intruders, indicating that they are unable of individual recognition, contrary to Pachycondyla. Additionally, the variation...... in chemical profiles of Lasius and Pachycondyla queens is comparable, thus informational constraints are unlikely to apply. We conclude that selection pressure from the social context is of crucial significance for the sophistication of recognition systems....

  8. Sexual Cooperation: Mating Increases Longevity in Ant Queens

    DEFF Research Database (Denmark)

    Schrempf, Alexandra; Heinze, Jürgen; Cremer, Sylvia

    2005-01-01

    history of ants, however, is expected to reduce sexual conflict; whereas most insect females show repeated phases of mating and reproduction, ant queens mate only during a short period early in life and undergo a lifelong commitment to their mates by storing sperm [5] . Furthermore, sexual offspring can......Divergent reproductive interests of males and females often cause sexual conflict [1] and [2] . Males of many species manipulate females by transferring seminal fluids that boost female short-term fecundity while decreasing their life expectancy and future reproductivity [3] and [4] . The life...... only be reared after a sterile worker force has been built up [5] . Therefore, the males should also profit from a long female lifespan. In the ant Cardiocondyla obscurior, mating indeed has a positive effect on the lifetime reproductive success of queens. Queens that mated to either one fertile or one...

  9. Quantifying Quantumness and the Quest for Queens of Quantum

    CERN Document Server

    Giraud, Olivier; Braun, Daniel

    2010-01-01

    We introduce a measure of ''quantumness'' for any quantum state in a finite dimensional Hilbert space, based on the distance between the state and the convex set of classical states. The latter are defined as states that can be written as a convex sum of projectors onto coherent states. We derive general properties of this measure of non-classicality, and use it to identify for a given dimension of Hilbert space what are the "Queen of Quantum" states, i.e. the most non-classical quantum states. In three dimensions we obtain the Queen of Quantum state analytically and show that it is unique up to rotations. In up to 11-dimensional Hilbert spaces, we find the Queen of Quantum states numerically, and show that in terms of their Majorana representation they are highly symmetric bodies, which for dimensions 5 and 7 correspond to Platonic bodies.

  10. Standard methods for rearing and selection of Apis mellifera queens

    DEFF Research Database (Denmark)

    Büchler, Ralph; Andonov, Sreten; Bienefeld, Kaspar;

    2013-01-01

    Here we cover a wide range of methods currently in use and recommended in modern queen rearing, selection and breeding. The recommendations are meant to equally serve as standards for both scientific and practical beekeeping purposes. The basic conditions and different management techniques...... methods and data preconditions for the estimation of breeding values which integrate pedigree and performance data from as many colonies as possible are described as the most efficient selection method for large populations. Alternative breeding programmes for small populations or certain scientific...... and quality control of queens complete the queen rearing section. The improvement of colony traits usually depends on a comparative testing of colonies. Standardized recommendations for the organization of performance tests and the measurement of the most common selection characters are presented. Statistical...

  11. Nano-watt fueling from a micro-scale microbial fuel cell using black tea waste

    KAUST Repository

    Rojas, Jhonathan Prieto

    2016-02-03

    In this report, we show the rapid assessment of black tea as potential fuel to power up nanopower systems using a microsized, simplistic and sustainable air-cathode microbial fuel cell. It was found that tea produced more power compared with traditional sodium acetate media due in part to its acidophilic pH and its higher organics content. Although high internal resistance remains a big concern, this simple, curiosity-driven experiment gave us the preliminary results to say that energy could be extracted from the reuse of waste resources such the collection of our afternoon-tea\\'s leftovers.

  12. Catalytic Enhancement of Carbon Black and Coal-Fueled Hybrid Direct Carbon Fuel Cells

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    was investigated using current-voltage-power density curves. In the anode chamber, catalysts are mixed with the carbon-carbonate mixture. These catalysts include various manganese oxides (MnO2, Mn2O3, Mn3O4, MnO), metal carbonates (Ag2CO3, MnCO3, Ce2(CO3)3), metals (Ag, Ce, Ni), doped-ceria (CeO2, Ce1-xGdxO2-x/2......, Ce1-xREExO2-δ (REE = Pr, Sm)) and metal oxides (LiMn2O4, Ag2O). Materials showing the highest activity in carbon black (Mn2O3, CeO2, Ce0.6Pr0.4O2-δ, Ag2O) were subsequently tested for catalytic activity toward bituminous coal, as revealed by both I-V-P curves and electrochemical impedance......Hybrid direct carbon fuel cells (HDCFCs) consisting of a solid carbon (carbon black)-molten carbonate ((62–38 wt% Li-K)2CO3) mixtures in the anode chamber of an anode-supported solid oxide fuel cell type full-cell are tested for their electrochemical performance between 700 and 800°C. Performance...

  13. 78 FR 36426 - Safety Zone; Queen's Cup; Lake Michigan; Milwaukee, WI

    Science.gov (United States)

    2013-06-18

    ... DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking TFR... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Queen's Cup; Lake Michigan; Milwaukee, WI... Queen's Cup Regatta. The Queen's Cup Regatta is a race from Milwaukee, WI to Ludington, MI that...

  14. Gender-bias primes elicit queen-bee responses among senior Policewomen

    NARCIS (Netherlands)

    Derks, B.; Laar, C. van; Ellemers, N.; Groot, K. de

    2011-01-01

    Queen bees are senior women in male-dominated organizations who have achieved success by emphasizing how they differ from other women. Although the behavior of queen bees tends to be seen as contributing to gender disparities in career outcomes, we argue that queen-bee behavior is actually a result

  15. Selection against aerial dispersal in ants: two non-flying queen phenotypes in Pogonomyrmex laticeps.

    Directory of Open Access Journals (Sweden)

    Christian Peeters

    Full Text Available The South American seed-harvester ant Pogonomyrmex laticeps has dimorphic queens: ergatoid (permanently wingless and brachypterous (short, non-functional wings. Surveys in western Argentina indicated that colonies near Chilecito, La Rioja Province, produced only ergatoid queens, while those near Punta Balasto, Catamarca Province (263 km away, produced only brachypterous queens. Brachypterous queens were significantly larger than ergatoid queens for 10 of 11 external characters, but both phenotypes had comparable reproductive potential, i.e., a spermatheca and a similar number of ovarioles. Using normal winged queens of the closely related P. uruguayensis for comparison, we determined that both queen phenotypes in P. laticeps had a full set of dorsal thoracic sclerites, albeit each sclerite was much reduced, whereas workers had a thorax without distinct dorsal sclerites. Sclerites were fused and immobile in ergatoid queens, while they were separable and fully articulated in brachypterous queens. Both phenotypes lacked the big indirect flight muscles, but brachypterous queens retained the tiny direct flight muscles. Overall, this dimorphism across populations indicates that there are alternative solutions to selective pressures against flying queens. We lack field data about colony founding strategy (independent or dependent for either queen phenotype, but colonies at both sites produced numerous gynes, and we infer that all foundresses initiate colonies independently and are obligate foragers.

  16. Deformed wing virus can be transmitted during natural mating in honey bees and infect the queens

    Science.gov (United States)

    Amiri, Esmaeil; Meixner, Marina D.; Kryger, Per

    2016-01-01

    Deformed wing virus is an important contributor to honey bee colony losses. Frequently queen failure is reported as a cause for colony loss. Here we examine whether sexual transmission during multiple matings of queens is a possible way of virus infection in queens. In an environment with high prevalence of deformed wing virus, queens (n = 30) were trapped upon their return from natural mating flights. The last drone’s endophallus (n = 29), if present, was removed from the mated queens for deformed wing virus quantification, leading to the detection of high-level infection in 3 endophalli. After oviposition, viral quantification revealed that seven of the 30 queens had high-level deformed wing virus infections, in all tissues, including the semen stored in the spermathecae. Two groups of either unmated queens (n = 8) with induced egg laying, or queens (n = 12) mated in isolation with drones showing comparatively low deformed wing virus infections served as control. None of the control queens exhibited high-level viral infections. Our results demonstrate that deformed wing virus infected drones are competitive to mate and able to transmit the virus along with semen, which occasionally leads to queen infections. Virus transmission to queens during mating may be common and can contribute noticeably to queen failure. PMID:27608961

  17. Queen movement during colony emigration in the facultatively polygynous ant Pachycondyla obscuricornis

    Science.gov (United States)

    Pezon, Antoine; Denis, Damien; Cerdan, Philippe; Valenzuela, Jorge; Fresneau, Dominique

    2005-01-01

    In ants, nest relocations are frequent but nevertheless perilous, especially for the reproductive caste. During emigrations, queens are exposed to predation and face the risk of becoming lost. Therefore the optimal strategy should be to move the queen(s) swiftly to a better location, while maintaining maximum worker protection at all times in the new and old nests. The timing of that event is a crucial strategic issue for the colony and may depend on queen number. In monogynous colonies, the queen is vital for colony survival, whereas in polygynous colonies a queen is less essential, if not dispensable. We tested the null hypothesis that queen movement occurs at random within the sequence of emigration events in both monogynous and polygynous colonies of the ponerine ant Pachycondyla obscuricornis. Our study, based on 16 monogynous and 16 polygynous colony emigrations, demonstrates for the first time that regardless of the number of queens per colony, the emigration serial number of a queen occurs in the middle of all emigration events and adult ant emigration events, but not during brood transport events. It therefore appears that the number of workers in both nests plays an essential role in the timing of queen movement. Our results correspond to a robust colony-level strategy since queen emigration is related neither to colony size nor to queen number. Such an optimal strategy is characteristic of ant societies working as highly integrated units and represents a new instance of group-level adaptive behaviors in social insect colonies.

  18. Characterization of the nanosized porous structure of black Si solar cells fabricated via a screen printing process

    Institute of Scientific and Technical Information of China (English)

    Tang Yehua; Fei Jianming; Cao Hongbin; Zhou Chunlan; Wang Wenjing; Zhou Su; Zhao Yan; Zhao Lei; Li Hailing; Yan Baojun; Chen Jingwei

    2012-01-01

    A silicon (Si) surface with a nanosized porous structure was formed via simple wet chemical etching catalyzed by gold (Au) nanoparticles on p-type Cz-Si (100).The average reflectivity from 300 to 1200 nm was less than 1.5%.Black Si solar cells were then fabricated using a conventional production process.The results reflected the output characteristics of the cells fabricated using different etching depths and emitter dopant profiles.Heavier dopants and shallower etching depths should be adopted to optimize the black Si solar cell output characteristics.The efficiency at the optimized etching time and dopant profile was 12.17%.However,surface passivation and electrode contact due to the nanosized porous surface structure are still obstacles to obtaining high conversion efficiency for the black Si solar cells.

  19. Effect of black raspberry extract in inhibiting NFkappa B dependent radioprotection in human breast cancer cells.

    Science.gov (United States)

    Madhusoodhanan, Rakhesh; Natarajan, Mohan; Singh, Jamunarani Veeraraghavan Nisha; Jamgade, Ambarish; Awasthi, Vibhudutta; Anant, Shrikant; Herman, Terence S; Aravindan, Natarajan

    2010-01-01

    Black raspberry extracts (RSE) have been shown to inhibit cancer cell growth and stimulate apoptosis. Also, studies have demonstrated that RSE inhibits transcriptional regulators including NFkappa B. Accordingly, we investigated the effect of RSE in inhibiting radiation (IR) induced NFkappa B mediated radioprotection in breast adenocarcinoma cells. MCF-7 cells were exposed to IR (2Gy), treated with RSE (0.5, 1.0, 2.0 micro g/ml) or treated with RSE (1.0 micro g/ml) followed by IR exposure, and harvested after 1, 3, 6, 24, 48, and 72 h. NFkappa B DNA-binding activity was measured by EMSA and phosphorylated Ikappa Balpha by immunoblotting. Expression of IAP1, IAP2, XIAP and survivin were measured by QPCR and immunoblotting. Cell survival was measured using MTT assay and cell death using Caspase-3/7 activity. Effect of RSE on IR induced MnSOD, TNFalpha, IL-1alpha and MnSOD activity was also determined. RSE inhibited NFkappa B activity in a dose-dependent manner. Also, RSE inhibited IR-induced sustained activation of NFkappa B, and NFkappa B regulated IAP1, IAP2, XIAP, and survivin. In addition, RSE inhibited IR-induced TNFalpha, IL-1alpha, and MnSOD levels and MnSOD activity. RSE suppressed cell survival and enhanced cell death. These results suggest that RSE may act as a potent radiosensitizer by overcoming the effects of NFkappa B mediated radioprotection in human breast cancer cells.

  20. Queen of Children Teacher Gives Heart to Students

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    WANG Huiqin, 48, is an English teacher at the Beijing Yanjingli High School. She started her career as "queen of children" at 20. After so many years of teaching, she has acquired unique skills that enable her to effectively educate and redeem students who lag behind the rest of the class. No matter how naughty or mischievous the

  1. Non-transferable signals on ant queen eggs

    DEFF Research Database (Denmark)

    D'Ettorre, Patrizia; Tofilski, Adam; Heinze, Jürgen;

    2006-01-01

    , selfish individuals may evade policing. What factors prevent individuals from being able to evade policing? In the ant Pachycondyla inversa, workers kill (police) worker-laid eggs. Because the colony keeps eggs in piles and worker-laid and queen-laid eggs are chemically distinct, worker-laid eggs might...

  2. King Harald V and Queen Sonja of Norway visit CERN

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Norway's King Harald V and Queen Sonja take a tour of the ATLAS detector with CERN's Director-General Robert Aymar in April 2006. During their visit the royal party met with members of CERN's Norwegian community. A group of about 40 students greeted the royal motorcade with a belting rendition of 'The King's Song', Norway's royal anthem.

  3. Ross Ice Shelf and the Queen Maude Mounains, Antarctica

    Science.gov (United States)

    1991-01-01

    Part of the Ross Ice Shelf and the Queen Maude Mounains of Antarctica (55.5N, 178.0W) are in the background of this scene, oriented toward the south. Low stratocumulus clouds are predominant throughout most of the scene.

  4. Queens Tri-School Confederation, 1991-92 Evaluation Report.

    Science.gov (United States)

    Hannah, Susan; Dworkowitz, Barbara

    An evaluation was done of the Queens Tri-School Confederation, three high schools in the New York City Public Schools funded by a federal grant from the Magnet Schools Assistance Program. The grant provided Hillcrest, Jamaica, and Thomas A. Edison High Schools with funds to develop or expand emergency technician programs at Hillcrest; a law…

  5. "Air Queen" Boeing 747’s Anniversary

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>The world’s well-known Boeing 747 aircraft completed its maiden flight on February 9, 1969, rewriting the history of the world’s civil aviation.Since 1970 when it was put into operation, Boeing 747s,dubbed as "air queen," have carried 3.6 billion passengers by flying for 64.8

  6. Cooperation, conflict, and the evolution of queen pheromones.

    Science.gov (United States)

    Kocher, Sarah D; Grozinger, Christina M

    2011-11-01

    While chemical communication regulates individual behavior in a wide variety of species, these communication systems are most elaborated in insect societies. In these complex systems, pheromones produced by the reproductive individuals (queens) are critical in establishing and maintaining dominant reproductive status over hundreds to thousands of workers. The proximate and ultimate mechanisms by which these intricate pheromone communication systems evolved are largely unknown, though there has been much debate over whether queen pheromones function as a control mechanism or as an honest signal facilitating cooperation. Here, we summarize results from recent studies in honey bees, bumble bees, wasps, ants and termites. We further discuss evolutionary mechanisms by which queen pheromone communication systems may have evolved. Overall, these studies suggest that queen-worker pheromone communication is a multi-component, labile dialog between the castes, rather than a simple, fixed signal-response system. We also discuss future approaches that can shed light on the proximate and ultimate mechanisms that underlie these complex systems by focusing on the development of increasingly sophisticated genomic tools and their potential applications to examine the molecular mechanisms that regulate pheromone production and perception.

  7. The Queen's Two Bodies: Sor Juana and New Spain's Vicereines

    Science.gov (United States)

    Thomas, George Anthony

    2009-01-01

    The work of Sor Juana Ines de la Cruz contains many examples of positive representations of the Queens of Spain and the Vicereines of New Spain. These poetic portraits serve to counter the primarily misogynistic portrayals of ruling women of the seventeenth century. Most importantly, Sor Juana increased the visibility of the vicereine in colonial…

  8. Retinal ganglion cell density of the black rhinoceros (Diceros bicornis): calculating visual resolution.

    Science.gov (United States)

    Pettigrew, John D; Manger, Paul R

    2008-01-01

    A single right retina from a black rhinoceros was whole mounted, stained and analyzed to determine the visual resolution of the rhinoceros, an animal with reputedly poor eyesight. A range of small (15-microm diameter) to large (100-microm diameter) ganglion cell types was seen across the retina. We observed two regions of high density of retinal ganglion cells at either end of a long, but thin, horizontal streak. The temporal specialization, which receives light from the anterior visual field, exhibited a ganglion cell density of approximately 2000/mm2, while the nasal specialization exhibited a density of approximately 1500/mm2. The retina exhibited a ganglion cell density bias toward the upper half, especially so, the upper temporal quadrant, indicating that the rhinoceros would be processing visual information from the visual field below the anterior horizon for the most part. Our calculations indicate that the rhinoceros has a visual resolution of 6 cycles/degree. While this resolution is one-tenth that of humans (60 cycles/deg) and less than that of the domestic cat (9 cycles/deg), it is comparable to that of the rabbit (6 cycles/deg), and exceeds that seen in a variety of other mammals including seals, dolphins, microbats, and rats. Thus, the reputation of the rhinoceros as a myopic, weakly visual animal is not supported by our observations of the retina. We calculate that the black rhinoceros could readily distinguish a 30 cm wide human at a distance of around 200 m given the appropriate visual background.

  9. 75 FR 68397 - DeQueen and Eastern Railroad, LLC-Acquisition and Operation Exemption-DeQueen and Eastern...

    Science.gov (United States)

    2010-11-05

    ... border) and milepost 87.0 (Perkins, Ark.), including auxiliary, temporary storage, and spur tracks, in Howard and Sevier Counties, Ark.\\1\\ \\1\\ DQE states that it intends to interchange traffic at De Queen, Ark. with Kansas City Southern Railway Company, at Perkins with Union Pacific Railroad Company, and...

  10. Deformed wing virus can be transmitted during natural mating in honey bees and infect the queens

    DEFF Research Database (Denmark)

    Amiri, Esmaeil; Meixner, Marina D.; Kryger, Per

    2016-01-01

    prevalence of deformed wing virus, queens (n = 30) were trapped upon their return from natural mating flights. The last drone’s endophallus (n = 29), if present, was removed from the mated queens for deformed wing virus quantification, leading to the detection of high-level infection in 3 endophalli. After...... oviposition, viral quantification revealed that seven of the 30 queens had high-level deformed wing virus infections, in all tissues, including the semen stored in the spermathecae. Two groups of either unmated queens (n = 8) with induced egg laying, or queens (n = 12) mated in isolation with drones showing...... comparatively low deformed wing virus infections served as control. None of the control queens exhibited high-level viral infections. Our results demonstrate that deformed wing virus infected drones are competitive to mate and able to transmit the virus along with semen, which occasionally leads to queen...

  11. Colony failure linked to low sperm viability in honey bee (Apis mellifera) queens and an exploration of potential causative factors

    Science.gov (United States)

    Queen health is closely linked to colony performance in honey bees as a single queen is normally responsible for all egg laying and brood production within the colony. In the U. S. in recent years, queens have been failing at a high rate; with 50% or greater of queens replaced in colonies within 6 m...

  12. One-step Fabrication of Nanoporous Black Silicon Surfaces for Solar Cells using Modified Etching Solution

    Institute of Scientific and Technical Information of China (English)

    Ye-hua Tang; Chun-lan Zhou; Su Zhou; Yan Zhao; Wen-jing Wang; Jian-ming Fei; Hong-bin Cao

    2013-01-01

    Currently,a conventional two-step method has been used to generate black silicon (BS)surfaces on silicon substrates for solar cell manufacturing.However,the performances of the solar cell made with such surface generation method are poor,because of the high surface recombination caused by deep etching in the conventional surface generation method for BS.In this work,a modified wet chemical etching solution with additives was developed.A zhomogeneous BS layer with random porous structure was obtained from the modified solution in only one step at room temperature.The BS layer had low reflectivity and shallow etching depth.The additive in the etch solution performs the function of pH-modulation.After 16-min etching,the etching depth in the samples was approximately 200 nm,and the spectrum-weighted-reflectivity in the range from 300 nm to 1200 nm was below 5%,BS solar cells were fabricated in the production line.The decreased etching depth can improve the electrical performance of solar cells because of the decrease in surface recombination.An efficiency of 15,63% for the modified etching BS solar cells was achieved on a large area,ptype single crystalline silicon substrate with a 624.32-mV open circuit voltage and a 77.88%fill factor.

  13. Black Phosphorus Quantum Dots for Hole Extraction of Typical Planar Hybrid Perovskite Solar Cells.

    Science.gov (United States)

    Chen, Wei; Li, Kaiwen; Wang, Yao; Feng, Xiyuan; Liao, Zhenwu; Su, Qicong; Lin, Xinnan; He, Zhubing

    2017-02-02

    Black phosphorus, famous as two-dimensional (2D) materials, shows such excellent properties for optoelectronic devices such as tunable direct band gap, extremely high hole mobility (300-1000 cm(2)/(V s)), and so forth. In this Letter, facile processed black phosphorus quantum dots (BPQDs) were successfully applied to enhance hole extraction at the anode side of the typical p-i-n planar hybrid perovskite solar cells, which remarkably improved the performance of devices with photon conversion efficiency ramping up from 14.10 to 16.69%. Moreover, more detailed investigations by c-AFM, SKPM, SEM, hole-only devices, and photon physics measurements discover further the hole extraction effect and work mechanism of the BPQDs, such as nucleation assistance for the growth of large grain size perovskite crystals, fast hole extraction, more efficient hole transfer, and suppression of energy-loss recombination at the anode interface. This work definitely paves the way for discovering more and more 2D materials with high electronic properties to be used in photovoltaics and optoelectronics.

  14. Sulfonated carbon black-based composite membranes for fuel cell applications

    Indian Academy of Sciences (India)

    Hacer Doǧan; Emel Yildiz; Metin Kaya; Tülay Y Inan

    2013-08-01

    Two different commercial grade carbon black samples, Cabot Regal 400R (C1) and Cabot Mogul L (C2), were sulfonated with diazonium salt of sulfanilic acid. The resultant sulfonated carbon black samples (S–C) were characterized by Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Composite membranes were then prepared using S–C as fillers and sulfonated poly(ether ether ketone) (SPEEK) as polymer matrix with three different sulfonation degrees (DS = 60, 70 and 82%). Structure and properties of the composite membranes were characterized by FTIR, TGA, scanning electron microscopy, proton conduction, water uptake, ion exchange capacity and chemical stability. Incorporation of S–C particles above 0.25 wt% caused decrease in chemical stability. Pristine and composite membranes prepared from SPEEK82 decomposed completely in <1 h, which is undesirable for fuel cell applications. SPEEK60 membrane having wt% of 0.25–0.5 with S–C particles led to higher proton conductivity than that of pristine membrane. No positive effect was observed on the properties of the composite membranes with the addition of S–C particles at high concentrations due to the agglomeration problems and decrease in the content of conductive polymer matrix.

  15. Optical characterization of nanopillar black silicon for plasmonic and Solar cell application

    Science.gov (United States)

    Gartia, M. R.; Chen, Y.; Xu, Z.; Bordain, Y. C.; Eichorst, J.; Mabon, J. C.; Soares, J. A. N. de T.; Clegg, R. M.; Liu, G. L.

    2011-10-01

    With the goal of improving photo-absorption of photovoltaic device and for plasmonic application we have fabricated nanopillar black silicon devices through etching-passivation technique which does not require any photomask and whole wafer scale uniformity is achieved at room temperature in a short time. We have carried out thorough optical characterization for nanopillar black silicon devices to be used for solar cell and plasmonic applications. Cathodoluminescence (CL), current dependent CL spectroscopy, photoluminescence (at room temperature and 77 K), Raman spectroscopy, reflectance and absorption measurement have been performed on the device. A thin layer of Ag is deposited to render with plasmonic property and the plasmonic effect is probed using surface plasmon enhanced fluorescence, angle dependent reflectance measurements, high resolution cathodoluminescence (CL), surface enhanced Raman spectroscopy (SERS) measurement and Fluorescence Lifetime Imaging Microscopy (FLIM) experiment. We obtained reduction in optical reflection of ~ 12 times on b-Si substrate from UV to NIR range, the nanostructured fluorescence enhancement of ~40 times and the Raman scattering enhancement factor of 6.4×107.

  16. Growth stimulating effect on queen bee larvae of histone deacetylase inhibitors.

    Science.gov (United States)

    Huang, Chung-Yang; Chi, Li-Ling; Huang, Wei-Jan; Chen, Yue-Wen; Chen, Wei-Jung; Kuo, Yu-Cheng; Yuan, Cheng Mike; Chen, Chia-Nan

    2012-06-20

    Royal jelly (RJ) is a widely used natural food. It is also a major source of nutrition for queen bees and plays a key role in their development. RJ is secreted from the hypopharyngeal and mandibular glands of young adult worker bees. The regulation of gene expression in these two glands may influence the development of queen bees by affecting the content of RJ. This study investigated the epigenetic effects in these two glands in young adult worker bees treated with histone deacetylase inhibitors (HDACis), a U.S. Food and Drug Administration-approved drug, suberoylanilide hydroxamic acid (SAHA), and NBM-HD-1, a novel compound synthesized in this laboratory. Western blot analyses indicated that the levels of acetyl-histone 3 and p21 protein expression in MCF-7 cells increased markedly after treatment with NBM-HD-1. The data proved that NBM-HD-1 was a novel and potent HDACi. Furthermore, a method of affecting epigenetic regulation of the mrjp family gene in the hypopharyngeal and mandibular glands of young adult worker bees was developed by feeding young adult worker bees HDACi. Epigenetic regulation produced several important biological effects. A marked change in the protein composition of the RJ secreted from these treated bees was found. Only the ratio of specific major royal jelly protein 3 (MRJP3) was significantly altered in the treated bees versus the untreated controls. Other MRJP family proteins did not change. This alteration in the ratio of royal jelly proteins resulted in a significant increase in the body size of queen bee larvae. The data seem to suggest that HDACis may play an important role in the epigenetic regulation of the hypopharyngeal and mandibular glands of young adult worker bees. They appear to change mrjp3 gene expression and alter the ratio of MRJP3 protein in RJ. This study presents the first evidence that HDACis are capable of regulating the ratio of MRJP3 proteins in RJ, which has the potential to change the body size of queen bees

  17. SOLVING THE SHUGART QUEEN SAND PENASCO UNIT DECLINING PRODUCTION PROBLEM

    Energy Technology Data Exchange (ETDEWEB)

    Lowell Deckert

    2000-08-25

    The Penasco Shugart Queen Sand Unit located in sections 8, 9, 16 & 17, T18S, 31E Eddy County New Mexico is operated by MNA Enterprises Ltd. Co. Hobbs, NM. The first well in the Unit was drilled in 1939 and since that time the Unit produced 535,000 bbl of oil on primary recovery and 375,000 bbl of oil during secondary recovery operations that commenced in 1973. The Unit secondary to primary ratio is 0.7, but other Queen waterfloods in the area had considerably larger S/P ratios. On June 25 1999 MNA was awarded a grant under the Department of Energy's ''Technology Development with Independents'' program. The grant was used to fund a reservoir study to determine if additional waterflood reserves could be developed. A total of 14 well bores that penetrate the Queen at 3150 ft are within the Unit boundaries. Eleven of these wells produced oil during the past 60 years. Production records were pieced together from various sources including the very early state production records. One very early well had a resistivity log, but nine of the wells had no logs, and four wells had gamma ray-neutron count-rate perforating logs. Fortunately, recent offset deep drilling in the area provided a source of modern logs through the Queen. The logs from these wells were used to analyze the four old gamma ray-neutron logs within the Unit. Additionally the offset well log database was sufficient to construct maps through the unit based on geostatistical interpolation methods. The maps were used to define the input parameters required to simulate the primary and secondary producing history. The history-matched simulator was then used to evaluate four production scenarios. The best scenario produces 51,000 bbl of additional oil over a 10-year period. If the injection rate is held to 300 BWPD the oil rate declines to a constant 15 BOPD after the first year. The projections are reasonable when viewed in the context of the historical performance ({approx}30 BOPD with a

  18. No evidence of volatile chemicals regulating reproduction in a multiple queen ant

    Science.gov (United States)

    Coston, Duncan J.; Gill, Richard J.; Hammond, Robert L.

    2011-07-01

    Efficient cooperation in eusocial insect colonies requires effective communication, and there is abundant evidence of non-volatile chemicals playing a role in regulating reproduction within colonies. In contrast, there have been fewer studies investigating the role of volatile chemicals. This study investigated the potential role of volatile chemicals in regulating queen reproduction either by directly inhibiting queen reproduction or by honestly signalling queen fecundity to workers. We tested this using multiple queen colonies of the ant ( Leptothorax acervorum) from a functionally monogynous population where one queen monopolizes all reproduction. Nine colonies, each with an established laying queen, were split to produce two colony fragments—one containing the reproducing queen (group 1) and one containing only previously non-reproducing queens (group 2). Each group was separated by a fine wire mesh preventing physical contact, but allowing volatile chemical contact. In each group 2 fragment, we found that a single formerly non-reproductive queen commenced reproduction and that the rate of egg laying and maximum number of eggs recorded did not significantly differ between groups 1 and 2, results that do not support volatile chemicals as playing a role in regulating queen reproduction. Instead, our findings suggest that physical contact is necessary to maintain functional monogyny.

  19. The Evolutionary Ecology of Multi-Queen Breeding in Ants

    DEFF Research Database (Denmark)

    Huszár, Dóra Borbála

    Ants, like other social insects, have evolved cooperative societies based on kinship. Colonies headed by a single breeding queen (monogyny) was the ancestral state but today ca. half of the ant species live in multi-queen societies (polygyny), which can sometimes reach extreme sizes (supercolony...... that only ants, not the other obligatorily social insects were able to decrease social and sexual conflicts sufficiently to make polygyny reach obligate form in some species. This can be explained by general ant biology, such as perennial lifehistories, foraging on foot instead of wings and having one...... nest types. High inbreeding also resulted in high genetic relatedness, which could imply substantial indirect fitness benefits since obviously negative fitness effects were not produced such as suboptimal body size, significant fluctuating asymmetry in reproductively relevant traits, or diploid male...

  20. Social life: the paradox of multiple-queen colonies.

    Science.gov (United States)

    Keller, L

    1995-09-01

    The evolution of animal societies in which some individuals forego their own reproductive opportunities to help others to reproduce poses an evolutionary paradox that can be traced to Darwin. Altruism may evolve through kin selection when the donor and recipient of altruistic acts are related to each other, as generally is the case in social birds and mammals. Similarly, social insect workers are highly related to the brood they rear when colonies are headed by a single queen. However, recent studies have shown that insect colonies frequently contain several queens, with the effect of decreasing relatedness among colony members. How can one account for the origin and maintenance of such colonies? This evolutionary enigma presents many of the same theoretical challenges as does the evolution of cooperative breeding and eusociality.

  1. Mutation spectrum in FE1-MUTA(TM) Mouse lung epithelial cells exposed to nanoparticulate carbon black

    DEFF Research Database (Denmark)

    Jacobsen, Nicklas Raun; White, Paul A; Gingerich, John

    2011-01-01

    It has been shown previously that carbon black (CB), Printex 90 exposure induces cII and lacZ mutants in the FE1-Muta(TM) Mouse lung epithelial cell line and causes oxidatively damaged DNA and the production of reactive oxygen species (ROS). The purpose of this study was to determine the mutation...

  2. Expanding the horizon: the Red Queen and potential alternatives

    OpenAIRE

    Tobler, M.; Schlupp, I

    2008-01-01

    The Red Queen hypothesis (RQH) is one of the most widely accepted hypotheses explaining the persistence of sexual reproduction despite its costs. It posits that sexual species, compared with asexuals, are more adept at countering parasites, because their per-generation recombination rate is higher. Despite theroretical support, current empirical studies have failed to provide unanimous support. Here, we suggest that future tests of the RQH should more thoroughly elucidate its underlying assum...

  3. CHEMICAL COMPOSITION AND SOMATIC CELL EVOLUTION DURING LACTATION IN ROMANIAN BLACK AND WHITE COWS

    Directory of Open Access Journals (Sweden)

    L.T. CZISZTER

    2013-12-01

    Full Text Available The aim of the paper was to study the evolution of the chemical composition and somatic cell count during lactation in Romanian Black and White cows and effect of calving season on the shape of the lactation curve. Lactations form 125 multiparous cows were studied. Milk yield and sampling were carried out using the official performance control method A4. Milk was analyzed for composition in infrared spectrometry and for SCC using a viscosimeter. Results were modeled using Wood’s incomplete gamma function y=abxe(-cx, and season effect was assessed using ANOVA/MANOVA. A discussion was carried out regarding the shape of the lactation curves for milk yield, each milk component and SCC. The calving season had a significant effect (p<0.005 on the shape of the lactation curve for milk yield, milk chemical composition and milk somatic cell count. Summer calving cows had flatter lactation curves for milk yield and composition compared to winter calving cows. For somatic cell count spring calving cows had the flattest lactation curve while autumn calving cows has the steepest lactation curve.

  4. Discovery of Black Dye Crystal Structure Polymorphs: Implications for Dye Conformational Variation in Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Cole, Jacqueline M; Low, Kian Sing; Gong, Yun

    2015-12-23

    We present the discovery of a new crystal structure polymorph (1) and pseudopolymorph (2) of the Black Dye, one of the world's leading dyes for dye-sensitized solar cells, DSSCs (10.4% device performance efficiency). This reveals that Black Dye molecules can adopt multiple low-energy conformers. This is significant since it challenges existing models of the Black Dye···TiO2 adsorption process that renders a DSSC working electrode; these have assumed a single molecular conformation that refers to the previously reported Black Dye crystal structure (3). The marked structural differences observed between 1, 2, and 3 make the need for modeling multiple conformations more acute. Additionally, the ordered form of the Black Dye (1) provides a more appropriate depiction of its anionic structure, especially regarding its anchoring group and NCS bonding descriptions. The tendency toward NCS ligand isomerism, evidenced via the disordered form 2, has consequences for electron injection and electron recombination in Black Dye embedded DSSC devices. Dyes 2 and 3 differ primarily by the absence or presence of a solvent of crystallization, respectively; solvent environment effects on the dye are thereby elucidated. This discovery of multiple Black Dye conformers from diffraction, with atomic-level definition, complements recently reported nanoscopic evidence for multiple dye conformations existing at a dye···TiO2 interface, for a chemically similar DSSC dye; those results emanated from imaging and spectroscopy, but were unresolved at the submolecular level. Taken together, these findings lead to the general notion that multiple dye conformations should be explicitly considered when modeling dye···TiO2 interfaces in DSSCs, at least for ruthenium-based dye complexes.

  5. Reclaiming the crown: queen to worker conflict over reproduction in Aphaenogaster cockerelli

    Science.gov (United States)

    Smith, Adrian A.; Hölldobler, Bert; Liebig, Jürgen

    2011-03-01

    In many social taxa, reproductively dominant individuals sometimes use aggression to secure and maintain reproductive status. In the social insects, queen aggression towards subordinate individuals or workers has been documented and is predicted to occur only in species with a small colony size and a low level of queen-worker dimorphism. We report queen aggression towards reproductive workers in the ant species Aphaenogaster cockerelli, a species with a relatively large colony size and a high level of reproductive dimorphism. Through analysis of cuticular hydrocarbon profiles, we show that queens are aggressive only to reproductively active workers. Non-reproductive workers treated with a hydrocarbon typical for reproductives are attacked by workers but not by queens, which suggests different ways of recognition. We provide possible explanations of why queen aggression is observed in this species.

  6. The origin and evolution of social insect queen pheromones: Novel hypotheses and outstanding problems.

    Science.gov (United States)

    Oi, Cintia A; van Zweden, Jelle S; Oliveira, Ricardo C; Van Oystaeyen, Annette; Nascimento, Fabio S; Wenseleers, Tom

    2015-07-01

    Queen pheromones, which signal the presence of a fertile queen and induce daughter workers to remain sterile, are considered to play a key role in regulating the reproductive division of labor of insect societies. Although queen pheromones were long thought to be highly taxon-specific, recent studies have shown that structurally related long-chain hydrocarbons act as conserved queen signals across several independently evolved lineages of social insects. These results imply that social insect queen pheromones are very ancient and likely derived from an ancestral signalling system that was already present in their common solitary ancestors. Based on these new insights, we here review the literature and speculate on what signal precursors social insect queen pheromones may have evolved from. Furthermore, we provide compelling evidence that these pheromones should best be seen as honest signals of fertility as opposed to suppressive agents that chemically sterilize the workers against their own best interests.

  7. Depression of brain dopamine and its metabolite after mating in European honeybee (Apis mellifera) queens

    Science.gov (United States)

    Harano, Ken-Ichi; Sasaki, Ken; Nagao, Takashi

    2005-07-01

    To explore neuro-endocrinal changes in the brain of European honeybee (Apis mellifera) queens before and after mating, we measured the amount of several biogenic amines, including dopamine and its metabolite in the brain of 6- and 12-day-old virgins and 12-day-old mated queens. Twelve-day-old mated queens showed significantly lower amounts of dopamine and its metabolite (N-acetyldopamine) than both 6- and 12-day-old virgin queens, whereas significant differences in the amounts of these amines were not detected between 6- and 12-day-old virgin queens. These results are explained by down-regulation of both synthesis and secretion of brain dopamine after mating. It is speculated that higher amounts of brain dopamine in virgin queens might be involved in activation of ovarian follicles arrested in previtellogenic stages, as well as regulation of their characteristic behaviors.

  8. Multiple pigment cell types contribute to the black, blue, and orange ornaments of male guppies (Poecilia reticulata.

    Directory of Open Access Journals (Sweden)

    Verena A Kottler

    Full Text Available The fitness of male guppies (Poecilia reticulata highly depends on the size and number of their black, blue, and orange ornaments. Recently, progress has been made regarding the genetic mechanisms underlying male guppy pigment pattern formation, but we still know little about the pigment cell organization within these ornaments. Here, we investigate the pigment cell distribution within the black, blue, and orange trunk spots and selected fin color patterns of guppy males from three genetically divergent strains using transmission electron microscopy. We identified three types of pigment cells and found that at least two of these contribute to each color trait. Further, two pigment cell layers, one in the dermis and the other in the hypodermis, contribute to each trunk spot. The pigment cell organization within the black and orange trunk spots was similar between strains. The presence of iridophores in each of the investigated color traits is consistent with a key role for this pigment cell type in guppy color pattern formation.

  9. Effect of Black Tea Consumption on Intracellular Cytokines, Regulatory T Cells and Metabolic Biomarkers in Type 2 Diabetes Patients.

    Science.gov (United States)

    Mahmoud, Fadia; Haines, David; Al-Ozairi, Ebaa; Dashti, Ali

    2016-03-01

    The present study was undertaken to evaluate the effects of black tea intake on inflammatory cytokines and metabolic biomarkers in Type 2 diabetes mellitus (T2DM). Thirty patients with T2DM were randomly assigned either to a High Intake (HI) group, consuming three cups (600 mL) of black tea per day; and a Low Intake (LI) group, administered 1 cup (200 mL) per day, each during a 12-week period. Intracellular cytokine expression, regulatory T cells (Treg), glycemic and lipid profiles were measured at baseline and following the tea intake period. Tea consumption correlated with major effects measured in peripheral blood of subjects that included significantly reduced glycated hemoglobin (HbA1c) levels, along with increased regulatory T cells CD3+ CD4+ CD25+ FOXP3, CD3+ CD4+ IL-10+ cells (an immunosuppressive phenotype), reduced (pro-inflammatory) CD3+ CD4+ IL-17+ cells and reduced Th1-associated CD3+ CD4+ IFN-Υ+ cells. Tea consumption was also observed to abolish the significance of an inverse correlation between total serum cholesterol and representation of CD4+ IL-4+ T cells, which may reflect protection against atopy-related oxidative stress. Outcomes of this study describe both advantages and limitations to consumption of black tea as an aid to sustained health maintenance by persons at-risk for TD2M and related obesity-associated metabolic syndromes.

  10. Glandular Epithelium as a Possible Source of a Fertility Signal in Ectatomma tuberculatum (Hymenoptera: Formicidae) Queens

    OpenAIRE

    Riviane Rodigues da Hora; Jacques Hubert Charles Delabie; Carolina Gonçalves dos Santos; José Eduardo Serrão

    2010-01-01

    The wax layer covering the insect's cuticle plays an important protective role, as for example, uncontrolled water loss. In social insects, wax production is well-known in some bees that use it for nest building. Curiously, mated-fertile queens of the ant Ectatomma tuberculatum produce an uncommon extra-wax coat and, consequently queens (mated-fertile females) are matte due to such extra cuticular hydrocarbon (CHC) coat that covers the cuticle and masks the brightness of the queens' cuticle w...

  11. Inhibitory effects of black pepper (Piper nigrum) extracts and compounds on human tumor cell proliferation, cyclooxygenase enzymes, lipid peroxidation and nuclear transcription factor-kappa-B.

    Science.gov (United States)

    Liu, Yunbao; Yadev, Vivek R; Aggarwal, Bharat B; Nair, Muraleedharan G

    2010-08-01

    Black pepper (Piper nigrum) and hot pepper (Capsicum spp.) are widely used in traditional medicines. Although hot Capsicum spp. extracts and its active principles, capsaicinoids, have been linked with anticancer and anti-inflammatory activities, whether black pepper and its active principle exhibit similar activities is not known. In this study, we have evaluated the antioxidant, anti-inflammatory and anticancer activities of extracts and compounds from black pepper by using proinflammatory transcription factor NF-kappaB, COX-1 and -2 enzymes, human tumor cell proliferation and lipid peroxidation (LPO). The capsaicinoids, the alkylamides, isolated from the hot pepper Scotch Bonnet were also used to compare the bioactivities of alkylamides and piperine from black pepper. All compounds derived from black pepper suppressed TNF-induced NF-kappaB activation, but alkyl amides, compound 4 from black pepper and 5 from hot pepper, were most effective. The human cancer cell proliferation inhibitory activities of piperine and alklyl amides in Capsicum and black pepper were dose dependant. The inhibitory concentrations 50% (IC50) of the alklylamides were in the range 13-200 microg/mL. The extracts of black pepper at 200 microg/mL and its compounds at 25 microg/mL inhibited LPO by 45-85%, COX enzymes by 31-80% and cancer cells proliferation by 3.5-86.8%. Overall, these results suggest that black pepper and its constituents like hot pepper, exhibit anti-inflammatory, antioxidant and anticancer activities.

  12. Nanostructured photoelectrochemical solar cell for nitrogen reduction using plasmon-enhanced black silicon

    Science.gov (United States)

    Ali, Muataz; Zhou, Fengling; Chen, Kun; Kotzur, Christopher; Xiao, Changlong; Bourgeois, Laure; Zhang, Xinyi; Macfarlane, Douglas R.

    2016-04-01

    Ammonia (NH3) is one of the most widely produced chemicals worldwide. It has application in the production of many important chemicals, particularly fertilizers. It is also, potentially, an important energy storage intermediate and clean energy carrier. Ammonia production, however, mostly uses fossil fuels and currently accounts for more than 1.6% of global CO2 emissions (0.57 Gt in 2015). Here we describe a solar-driven nanostructured photoelectrochemical cell based on plasmon-enhanced black silicon for the conversion of atmospheric N2 to ammonia producing yields of 13.3 mg m-2 h-1 under 2 suns illumination. The yield increases with pressure; the highest observed in this work was 60 mg m-2 h-1 at 7 atm. In the presence of sulfite as a reactant, the process also offers a direct solar energy route to ammonium sulfate, a fertilizer of economic importance. Although the yields are currently not sufficient for practical application, there is much scope for improvement in the active materials in this cell.

  13. Gene expression and variation in social aggression by queens of the harvester ant Pogonomyrmex californicus.

    Science.gov (United States)

    Helmkampf, Martin; Mikheyev, Alexander S; Kang, Yun; Fewell, Jennifer; Gadau, Jürgen

    2016-08-01

    A key requirement for social cooperation is the mitigation and/or social regulation of aggression towards other group members. Populations of the harvester ant Pogonomyrmex californicus show the alternate social phenotypes of queens founding nests alone (haplometrosis) or in groups of unrelated yet cooperative individuals (pleometrosis). Pleometrotic queens display an associated reduction in aggression. To understand the proximate drivers behind this variation, we placed foundresses of the two populations into social environments with queens from the same or the alternate population, and measured their behaviour and head gene expression profiles. A proportion of queens from both populations behaved aggressively, but haplometrotic queens were significantly more likely to perform aggressive acts, and conflict escalated more frequently in pairs of haplometrotic queens. Whole-head RNA sequencing revealed variation in gene expression patterns, with the two populations showing moderate differentiation in overall transcriptional profile, suggesting that genetic differences underlie the two founding strategies. The largest detected difference, however, was associated with aggression, regardless of queen founding type. Several modules of coregulated genes, involved in metabolism, immune system and neuronal function, were found to be upregulated in highly aggressive queens. Conversely, nonaggressive queens exhibited a striking pattern of upregulation in chemosensory genes. Our results highlight that the social phenotypes of cooperative vs. solitary nest founding tap into a set of gene regulatory networks that seem to govern aggression level. We also present a number of highly connected hub genes associated with aggression, providing opportunity to further study the genetic underpinnings of social conflict and tolerance.

  14. Ant Queen Egg-Marking Signals: Matching Deceptive Laboratory Simplicity with Natural Complexity

    DEFF Research Database (Denmark)

    van Zweden, Jelle Stijn; Heinze, Jürgen; Boomsma, Jacobus Jan;

    2009-01-01

    . Earlier correlative evidence indicated that, in the ant Pachycondyla inversa, the hydrocarbon 3,11-dimethylheptacosane (3,11-diMeC27) is more abundant on the surface of queen-laid eggs. Methodology We first tested the hypothesis that 3,11-diMeC27 functions as a queen egg-marking pheromone using laboratory...... that this compound by itself is not the natural queen egg-marking pheromone. We subsequently investigated the overall differences of entire chemical profiles of eggs, and found that queen-laid eggs in field colonies are more distinct from worker-laid eggs than in lab colonies, have more variation in profiles...

  15. Natural transmission of feline immunodeficiency virus from infected queen to kitten

    Directory of Open Access Journals (Sweden)

    Medeiros Sheila de

    2012-05-01

    Full Text Available Abstract Background Feline immunodeficiency virus (FIV is a naturally occurring lentivirus that infects cats. The primary mode of transmission occurs through bite wounds, and other routes are difficult to observe in nature. Findings The purpose of this study was to evaluate FIV transmission from queen to kitten in a colony of naturally infected stray cats. With this aim, a queen was monitored over a period of three years. A blood sample was taken to amplify and sequence gag, pol and env regions of the virus from the queen, two kittens and other cats from the colony. Conclusion Phylogenetic analysis showed evidence of queen to kitten transmission.

  16. Black silicon SERS substrate: effect of surface morphology on SERS detection and application of single algal cell analysis.

    Science.gov (United States)

    Deng, Yu-Luen; Juang, Yi-Je

    2014-03-15

    In this study, we have investigated the effect of the surface morphology of the black silicon substrate on surface enhanced Raman spectroscopy (SERS) and explored its application of single algal cell detection. By adjusting the O2 and SF6 flow rates in the cryogenic plasma etching process, different surface morphologies of the black silicon substrate was produced without performing the lithographic process. It was found the Raman signals were better enhanced as the tip density of the black silicon substrate increased. In addition, as the thickness of the deposited gold layer increased, the SERS effect increased as well, which could be owing to the generation of more hot spots by bridging individual silicon tips through deposition of gold layer. For the black silicon substrate with tip density of 30 tips/μm(2) and covered by 400 nm deposited gold layer, the detection limit of 10 fM R6G solution concentration with uniform SERS effect across the substrate was achieved. Furthermore, detection of individual algal cell (Chlorella vulgaris) was performed at the SERS substrate as fabricated and the Raman signals of carotenoid and lipid were substantially enhanced.

  17. Differences in beta-cell function and insulin secretion in Black vs. White obese adolescents: Do incretin hormones play a role?

    Science.gov (United States)

    Black youth are at higher risk for type 2 diabetes (T2D) than their White peers. Previously we demonstrated that for the same degree of insulin sensitivity, Black youth have an upregulated beta-cell function and insulin hypersecretion, in response to intravenous (IV) glucose, compared with Whites. T...

  18. Black silicon solar cell: analysis optimization and evolution towards a thinner and flexible future.

    Science.gov (United States)

    Roy, Arijit Bardhan; Dhar, Arup; Choudhuri, Mrinmoyee; Das, Sonali; Hossain, S Minhaz; Kundu, Avra

    2016-07-29

    Analysis and optimization of silicon nano-structured geometry (black silicon) for photovoltaic applications has been reported. It is seen that a unique class of geometry: micro-nanostructure has the potential to find a balance between the conflicting interests of reduced reflection for wide angles of incidence, reduced surface area enhancement due to the nano-structuring of the substrate and reduced material wastage due to the etching of the silicon substrate to realize the geometry itself. It is established that even optimally designed micro-nanostructures would not be useful for conventional wafer based approaches. The work presents computational studies on how such micro-nanostructures are more potent for future ultra-thin monocrystalline silicon absorbers. For such ultra-thin absorbers, the optimally designed micro-nanostructures provide additional advantages of advanced light management capabilities as it behaves as a lossy 2D photonic crystal making the physically thin absorber optically thick along with the ability to collect photo-generated carriers orthogonal to the direction of light (radial junction) for unified photon-electron harvesting. Most significantly, the work answers the key question on how thin the monocrystalline solar absorber should be so that optimum micro-nanostructure would be able to harness the incident photons ensuring proper collection so as to reach the well-known Shockley-Queisser limit of solar cells. Flexible ultra-thin monocrystalline silicon solar cells have been fabricated using nanosphere lithography and MacEtch technique along with a synergistic association of crystalline and amorphous silicon technologies to demonstrate its physical and technological flexibilities. The outcomes are relevant so that nanotechnology may be seamlessly integrated into the technology roadmap of monocrystalline silicon solar cells as the silicon thickness should be significantly reduced without compromising the efficiency within the next decade.

  19. Black silicon solar cell: analysis optimization and evolution towards a thinner and flexible future

    Science.gov (United States)

    Bardhan Roy, Arijit; Dhar, Arup; Choudhuri, Mrinmoyee; Das, Sonali; Minhaz Hossain, S.; Kundu, Avra

    2016-07-01

    Analysis and optimization of silicon nano-structured geometry (black silicon) for photovoltaic applications has been reported. It is seen that a unique class of geometry: micro-nanostructure has the potential to find a balance between the conflicting interests of reduced reflection for wide angles of incidence, reduced surface area enhancement due to the nano-structuring of the substrate and reduced material wastage due to the etching of the silicon substrate to realize the geometry itself. It is established that even optimally designed micro-nanostructures would not be useful for conventional wafer based approaches. The work presents computational studies on how such micro-nanostructures are more potent for future ultra-thin monocrystalline silicon absorbers. For such ultra-thin absorbers, the optimally designed micro-nanostructures provide additional advantages of advanced light management capabilities as it behaves as a lossy 2D photonic crystal making the physically thin absorber optically thick along with the ability to collect photo-generated carriers orthogonal to the direction of light (radial junction) for unified photon-electron harvesting. Most significantly, the work answers the key question on how thin the monocrystalline solar absorber should be so that optimum micro-nanostructure would be able to harness the incident photons ensuring proper collection so as to reach the well-known Shockley-Queisser limit of solar cells. Flexible ultra-thin monocrystalline silicon solar cells have been fabricated using nanosphere lithography and MacEtch technique along with a synergistic association of crystalline and amorphous silicon technologies to demonstrate its physical and technological flexibilities. The outcomes are relevant so that nanotechnology may be seamlessly integrated into the technology roadmap of monocrystalline silicon solar cells as the silicon thickness should be significantly reduced without compromising the efficiency within the next decade.

  20. Carbon black nanoparticles promote the maturation and function of mouse bone marrow-derived dendritic cells.

    Science.gov (United States)

    Koike, Eiko; Takano, Hirohisa; Inoue, Ken-Ichiro; Yanagisawa, Rie; Kobayashi, Takahiro

    2008-09-01

    Particulate matter including carbon black (CB) nanoparticles can enhance antigen-related inflammation and immunoglobulin production in vivo. Dendritic cells (DC) as antigen-presenting cells (APC) are the most capable inducers of immune responses. The present study was designed to determine whether CB nanoparticles affect the maturation/activation and function of DC in vitro. DC were differentiated from bone marrow (BM) cells of BALB/c mice by culture with granulocyte macrophage colony stimulating factor (GM-CSF). At day 8 of culture, BM-derived DC (BMDC) were exposed to CB nanoparticles with a diameter of 14nm or 56nm for 24h. The expression of major histocompatibility complex (MHC) class II, DEC205, CD80, and CD86 (maturation/activation markers of BMDC) was measured by flow cytometry. BMDC function was evaluated by an allogeneic mixed lymphocyte reaction (MLR) assay. CB nanoparticles significantly increased the expression of DEC205 and CD86 in BMDC and tended to increase MHC class II and CD80 expression; however, a size-dependent effect was not observed. On the other hand, BMDC-mediated MLR was significantly enhanced by the CB nanoparticles and the enhancement was greater by 14nm CB nanoparticles than by 56nm CB nanoparticles. Taken together, CB nanoparticles can promote the maturation/activation and function of BMDC, which could be related to their effects on allergic diseases and/or responses. In addition, BMDC-mediated MLR might be useful assay for in vitro screening for adjuvant activity of environmental toxicants.

  1. Joint effects of citrus peel use and black tea intake on the risk of squamous cell carcinoma of the skin

    Directory of Open Access Journals (Sweden)

    Harris Robin B

    2001-08-01

    Full Text Available Abstract Background Differences in tea drinking habits and/or citrus peel use are likely to vary by populations and could contribute to the inconsistencies found between studies comparing their consumption and cancer risk. Methods A population-based case-control study was used to evaluate the relationships between citrus peel use and black tea intake and squamous cell carcinoma (SCC of the skin. Moreover, we assessed the independent and interactive effects of citrus peel and black tea in the development of SCC. Results Hot and iced teas were consumed by 30.7% and 51.8% of the subjects, respectively. Peel consumption was reported by 34.5% of subjects. Controls were more likely than were cases to report citrus peel use (odds ratio (OR = 0.67 and hot tea intake (OR = 0.79. After adjustment for hot and iced tea intake, the ORs associated with citrus peel use were 0.55 and 0.69, respectively, whereas the corresponding adjusted ORs for hot and iced tea intake after adjustment for citrus peel use were 0.87 and 1.22 respectively. Compared with those who did not consume hot black tea or citrus peel, the adjusted ORs associated with sole consumption of hot black tea or citrus peel were 0.60 and 0.30, respectively. Subjects who reported consumption of both hot black tea and citrus peel had a significant marked decrease (OR= 0.22; 95% CI = 0.10 – 0.51 risk of skin SCC. Conclusion These results indicate that both citrus peel use and strong (hot black tea have independent potential protective effects in relation to skin SCC.

  2. SENSORY CHARACTERISTICS OF NATIVE CHICKEN QUEEN PINEAPPLE-CURED HAM

    Directory of Open Access Journals (Sweden)

    Dr. Lilibeth A. Roxas

    2015-01-01

    Full Text Available The potential of Native Chicken to be processed into palatable ham was conducted making use of Queen Pineapple (QP crude extract as one of the curing ingredients. Primarily, the main goal is to develop a protocol in the manufacture of processed native chicken ham and determine the organoleptic quality of native chicken ham product. The age of the bird and maturity of the fruit were considered for the best organoleptic quality of chicken ham. In this study, the combine injection and dry cure (CIDC method of the conventional formula was adopted. The desired amount of QP crude extract was first determined for the pump pickle. Curing salt was used for the control while different volume of pineapple crude extract was used in two treatments. The protocols for processing native chicken were developed using slaughter native chicken, and QP crude extract as curing ingredient for ham making. Color, flavor, juiciness and tenderness were among the desirable characteristics considered in this study. The sensory evaluation by trained panelists on QP-cured ham samples demonstrated comparable results. All the cooked meat samples were apparently acceptable to the sensory panel. The mean scores for flavor, juiciness and tenderness of meat samples have slight differences; however, they are not statistically significant. Indeed, native chicken can be processed into palatable ham with queen pineapple (Formosa variety extract that served as curing ingredient, flavor enhancer and tenderizer. Native Chicken QP-Cured ham is a commendable value-added product for both native chicken and queen pineapple by-products (butterball size.

  3. The facial reconstruction of an Ancient Egyptian Queen.

    Science.gov (United States)

    Manley, Bill; Eremin, Katherine; Shortland, Andrew; Wilkinson, Caroline

    2002-12-01

    The National Museums of Scotland Mummy Project has provided important new information about a burial excavated in Egypt. This has resulted in the facial reconstruction of a woman who was probably a queen at Thebes ca. 1570-1520 BCE. There are strong suggestions from the grave goods and her diet that this woman may have been ethnically Nubian rather than Egyptian. However, it is not yet possible to establish her ethnic identity for sure, so a definitive reconstruction of her appearance in life remains elusive.

  4. Queen Cleopatra and the other 'Cleopatras': their medical legacy.

    Science.gov (United States)

    Tsoucalas, Gregory; Kousoulis, Antonis A; Poulakou-Rebelakou, Effie; Karamanou, Marianna; Papagrigoriou-Theodoridou, Maria; Androutsos, George

    2014-05-01

    Cleopatra is a female figure widespread in Greece (especially in Macedonian territory), Egypt and Syria during the Hellenistic era. Ancient women doctors bearing the name Cleopatra have been identified by a systematic search through the ancient Greek, Latin and Egyptian bibliography, including original resources from the first century BC. Fictional and non-fictional figures have been distinguished and their works identified. Queen Cleopatra of Egypt, Galen's physician assistant, the outcast Metrodora, Cleopatra the Alchemist and Cleopatra the Gynaecologist deliver a story of medicine and name-giving that confuses researchers of the past and intrigues those of the present.

  5. Enhanced Activated Carbon Cathode Performance for Microbial Fuel Cell by Blending Carbon Black

    KAUST Repository

    Zhang, Xiaoyuan

    2014-02-04

    Activated carbon (AC) is a useful and environmentally sustainable catalyst for oxygen reduction in air-cathode microbial fuel cells (MFCs), but there is great interest in improving its performance and longevity. To enhance the performance of AC cathodes, carbon black (CB) was added into AC at CB:AC ratios of 0, 2, 5, 10, and 15 wt % to increase electrical conductivity and facilitate electron transfer. AC cathodes were then evaluated in both MFCs and electrochemical cells and compared to reactors with cathodes made with Pt. Maximum power densities of MFCs were increased by 9-16% with CB compared to the plain AC in the first week. The optimal CB:AC ratio was 10% based on both MFC polarization tests and three electrode electrochemical tests. The maximum power density of the 10% CB cathode was initially 1560 ± 40 mW/m2 and decreased by only 7% after 5 months of operation compared to a 61% decrease for the control (Pt catalyst, 570 ± 30 mW/m2 after 5 months). The catalytic activities of Pt and AC (plain or with 10% CB) were further examined in rotating disk electrode (RDE) tests that minimized mass transfer limitations. The RDE tests showed that the limiting current of the AC with 10% CB was improved by up to 21% primarily due to a decrease in charge transfer resistance (25%). These results show that blending CB in AC is a simple and effective strategy to enhance AC cathode performance in MFCs and that further improvement in performance could be obtained by reducing mass transfer limitations. © 2014 American Chemical Society.

  6. Potential increase in mating frequency of queens in feral colonies of Bombus terrestris introduced into Japan

    Science.gov (United States)

    Inoue, Maki N.; Saito, Fuki; Tsuchida, Koji; Goka, Koichi

    2012-10-01

    With the exception of several species, bumblebees are monandrous. We examined mating frequency in feral colonies of the introduced bumblebee Bombus terrestris in Japan . Using microsatellite markers, genotyping of sperm DNA stored in the spermatheca of nine queens detected multiple insemination paternities in one queen; the others were singly mated. The average effective paternity frequency estimated from the genotypes of queens and workers was 1.23; that estimated from the workers' genotype alone was 2.12. These values were greater than those of laboratory-reared colonies in the native ranges of B. terrestris. The genotypes of one or two workers did not match those of their queens or showed paternities different from those of their nestmates; this may have arisen from either queen takeover or drifting of workers. These alien workers were responsible for the heterogeneous genotype distribution within each B. terrestris colony, resulting in higher estimates of paternity frequency than of insemination frequency. The high mating frequency of introduced B. terrestris may have occurred by artificial selection through mass breeding for commercialization. Moreover, polyandrous queens may be selectively advantageous, because reproduction by such queens is less likely to be disturbed by interspecific mating than that by monandrous queens.

  7. The Queen Bee Phenomenon: Why Women Leaders Distance Themselves from Junior Women

    NARCIS (Netherlands)

    Derks, B.; Van Laar, C.; Ellemers, Naomi

    2016-01-01

    This contribution reviews work on the Queen Bee phenomenon whereby women leaders assimilate into masculine organizations, distance themselves from junior women and legitimize gender inequality in their organization. We propose that rather than being a source of gender inequality, the Queen Bee pheno

  8. Workers and alate queens of Solenopsis geminata share qualitatively similar but quantitatively different venom alkaloid chemistry

    Science.gov (United States)

    The cis and trans alkaloids from body extracts of workers and alate queens of the tropical fire ant, Solenopsis geminata (Hymenoptera: Formicidae), were successfully separated by silica gel chromatography, identified, and quantitated by GC-MS analysis. Both workers and alate queens produce primarily...

  9. Political Attention in a Coalition System: Analysing Queen's Speeches in the Netherlands 1945–2007

    NARCIS (Netherlands)

    Breeman, G.E.; Lowery, D.; Poppelaars, C.; Resodihardjo, S.; Timmermans, A.; Vries, de J.

    2009-01-01

    At the beginning of each Parliamentary session, the Dutch Queen gives a speech (Troonrede) in which she presents the government's policy goals and legislative agenda for the year to come. The general assumption is that newly elected governments will use agenda-setting moments such as the Queen's spe

  10. Queen's researchers make the grade: University boasts two of three finalists for million-dollar grant

    CERN Multimedia

    Armstrong, F E

    2003-01-01

    Two Queen's University researchers are among three Canadian finalists in a contest to win $1 million. Art McDonald, director of the Queen's-run Sudbury Neutrino Observatory Institute, and John Smol, Canada Research Chair in Environmental Change, have been nominated for the Gerhard Herzberg Canada Gold Medal for Science and Engineering (1 page).

  11. Evolution and hydrocarbon potential of Queen Charlotte basin, Canada

    Energy Technology Data Exchange (ETDEWEB)

    McWhae, J.R.

    1988-02-01

    The structural and depositional history of the Queen Charlotte basin, a complex Tertiary rift basin with extensive coeval volcanics, involves regional geology from the Pacific plate west of the Queen Charlotte transform fault to east of the Alexander-Wrangellia terrane, based on geophysics (including newly released seismic lines), revised stratigraphy, and well data. Eight offshore wells were drilled prior to 1970 and nine shallow onshore wells were drilled in or beyond the northwestern margin of the basin. The wells provide data on porosity, seal, maturation (geothermal and vitrinite reflectance data), and oil stains in sidewall cores of the Sockeye B-10 well in the Skonun formation, here 4500 m thick. The Skonun ranges from early Miocene (17 Ma) to latest Pliocene (2 Ma) in age and the lower part is regarded as the primary hydrocarbon objective, especially in the more southern part of the basin where more favorable depositional porosities occur in paralic and shelf sandstones. Higher-than-average geothermal temperatures, locally in the southwest corner of the basin related to oblique subduction of very young oceanic crust, may reach the hydrocarbon-generating threshold in the lower Skonun marine shales. The middle Cretaceous Haida subarkose appears to be a secondary reservoir - the thickest and cleanest of the post-collision volcaniclastics. Highly organic Lower Jurassic shales provide a second, probably oil-prone, source.

  12. Selfish strategies and honest signalling: reproductive conflicts in ant queen associations

    DEFF Research Database (Denmark)

    Holman, Luke; Dreier, Stephanie; d'Ettorre, Patrizia

    2010-01-01

    Social insects offer unique opportunities to test predictions regarding the evolution of cooperation, life histories and communication. Colony founding by groups of unrelated queens, some of which are later killed, may select for selfish reproductive strategies, honest signalling and punishment...... their reproductive output or produce dishonest, manipulative signals, providing a novel test of the evolutionary significance of queen pheromones. Queens produced fewer workers when their colony contained ample brood, but only in the presence of competitors, suggesting selfish conservation of resources. Several CHCs...... correlated with reproductive maturation, and to a lesser extent with productivity; the same hydrocarbons were more abundant on queens that were not killed, suggesting that workers select productive queens using these chemical cues. Our results highlight the role of honest signalling in the evolution...

  13. Conserved class of queen pheromones stops social insect workers from reproducing.

    Science.gov (United States)

    Van Oystaeyen, Annette; Oliveira, Ricardo Caliari; Holman, Luke; van Zweden, Jelle S; Romero, Carmen; Oi, Cintia A; d'Ettorre, Patrizia; Khalesi, Mohammadreza; Billen, Johan; Wäckers, Felix; Millar, Jocelyn G; Wenseleers, Tom

    2014-01-17

    A major evolutionary transition to eusociality with reproductive division of labor between queens and workers has arisen independently at least 10 times in the ants, bees, and wasps. Pheromones produced by queens are thought to play a key role in regulating this complex social system, but their evolutionary history remains unknown. Here, we identify the first sterility-inducing queen pheromones in a wasp, bumblebee, and desert ant and synthesize existing data on compounds that characterize female fecundity in 64 species of social insects. Our results show that queen pheromones are strikingly conserved across at least three independent origins of eusociality, with wasps, ants, and some bees all appearing to use nonvolatile, saturated hydrocarbons to advertise fecundity and/or suppress worker reproduction. These results suggest that queen pheromones evolved from conserved signals of solitary ancestors.

  14. Queen influence on workers behavior of the leaf-cutting ant Atta sexdens rubropilosa (Forel, 1908

    Directory of Open Access Journals (Sweden)

    L. Sousa-Souto

    Full Text Available In an ant colony, the queen is the single reproducer and can interact with her workers via pheromones and cuticular compounds. However, in most species queen importance is not restricted to reproduction: in the initial development of the colony, her presence might play a more important role. In this work, we studied the effects of queen absence on workers behavior displayed in the foraging arena. Ant’s mortality and refuse accumulation was also measured daily. The results showed that queen absence did not alter either workers behavior or foraging efficiency. However, we observed increased ant mortality accompanied by a decrease in refuse dumping outside the nest. These results corroborate the hypothesis that environmental factors are more important than intrinsical factors in the allocation of external tasks. Probably, the queen could only influence internal activities of the colony.

  15. An Efficient Antioxidant System in a Long-Lived Termite Queen

    Science.gov (United States)

    Tasaki, Eisuke; Kobayashi, Kazuya; Matsuura, Kenji; Iuchi, Yoshihito

    2017-01-01

    The trade-off between reproduction and longevity is known in wide variety of animals. Social insect queens are rare organisms that can achieve a long lifespan without sacrificing fecundity. The extended longevity of social insect queens, which contradicts the trade-off, has attracted much attention because it implies the existence of an extraordinary anti-aging mechanism. Here, we show that queens of the termite Reticulitermes speratus incur significantly lower oxidative damage to DNA, protein and lipid and have higher activity of antioxidant enzymes than non-reproductive individuals (workers and soldiers). The levels of 8-hydroxy-2’-deoxyguanosine (oxidative damage marker of DNA) were lower in queens than in workers after UV irradiation. Queens also showed lower levels of protein carbonyls and malondialdehyde (oxidative damage markers of protein and lipid, respectively). The antioxidant enzymes of insects are generally composed of catalase (CAT) and peroxiredoxin (Prx). Queens showed more than two times higher CAT activity and more than seven times higher expression levels of the CAT gene RsCAT1 than workers. The CAT activity of termite queens was also markedly higher in comparison with other solitary insects and the queens of eusocial Hymenoptera. In addition, queens showed higher expression levels of the Prx gene RsPRX6. These results suggested that this efficient antioxidant system can partly explain why termite queens achieve long life. This study provides important insights into the evolutionary linkage of reproductive division of labor and the development of queens’ oxidative stress resistance in social insects. PMID:28076409

  16. Black to Black

    DEFF Research Database (Denmark)

    Langkjær, Michael Alexander

    2012-01-01

    ’s a lifestyle I enjoy.” For Monáe, the tuxedo is both working clothes and a superhero uniform. Together with futuristic references to Fritz Lang’s dystopian Metropolis, her trademark starched shirt and tuxedo also recall Weimar and pre-war Berlin. While outwardly dissimilar, Sioux’s and Monáe’s shared black...... suggested that appreciation of the highly personal motives of both Siouxsie Sioux and Janelle Monáe in wearing black may be achieved via analogies with the minimalist sublime of American artists Frank Stella’s and Ad Reinhardt’s black canvasses....

  17. Maize black Mexican sweet suspension cultured cells are a convenient tool for studying aquaporin activity and regulation.

    Science.gov (United States)

    Cavez, Damien; Hachez, Charles; Chaumont, François

    2009-09-01

    Aquaporins (AQPs) are channel proteins that facilitate and regulate the permeation of water across biological membranes. Black Mexican sweet suspension cultured cells are a convenient model for studying the regulation of maize AQP expression and activity. Among other advantages, a single cell system allows the contribution of plasma membrane AQPs (PIPs, plasma membrane intrinsic proteins) to the membrane water permeability coefficient (P(f)) to be determined using biophysical measurement methods, such as the cell pressure probe or protoplast swelling assay. We generated a transgenic cell culture line expressing a tagged version of ZmPIP2;6 and used this material to demonstrate that the ZmPIP2;6 and ZmPIP2;1 isoforms physically interact. This kind of interaction could be an additional mechanism for regulating membrane water permeability by acting on the activity and/or trafficking of PIP hetero-oligomers.

  18. Differential antennal proteome comparison of adult honeybee drone, worker and queen (Apis mellifera L.).

    Science.gov (United States)

    Fang, Yu; Song, Feifei; Zhang, Lan; Aleku, Dereje Woltedji; Han, Bin; Feng, Mao; Li, Jianke

    2012-01-04

    To understand the olfactory mechanism of honeybee antennae in detecting specific volatile compounds in the atmosphere, antennal proteome differences of drone, worker and queen were compared using 2-DE, mass spectrometry and bioinformatics. Therefore, 107 proteins were altered their expressions in the antennae of drone, worker and queen bees. There were 54, 21 and 32 up-regulated proteins in the antennae of drone, worker and queen, respectively. Proteins upregulated in the drone antennae were involved in fatty acid metabolism, antioxidation, carbohydrate metabolism and energy production, protein folding and cytoskeleton. Proteins upregulated in the antennae of worker and queen bees were related to carbohydrate metabolism and energy production while molecular transporters were upregulated in the queen antennae. Our results explain the role played by the antennae of drone is to aid in perceiving the queen sexual pheromones, in the worker antennae to assist for food search and social communication and in the queen antennae to help pheromone communication with the worker and the drone during the mating flight. This first proteomic study significantly extends our understanding of honeybee olfactory activities and the possible mechanisms played by the antennae in response to various environmental, social, biological and biochemical signals.

  19. A conserved class of queen pheromones? Re-evaluating the evidence in bumblebees (Bombus impatiens).

    Science.gov (United States)

    Amsalem, Etya; Orlova, Margarita; Grozinger, Christina M

    2015-10-22

    The regulation of reproductive division of labour is a key component in the evolution of social insects. Chemical signals are important mechanisms to regulate worker reproduction, either as queen-produced pheromones that coercively inhibit worker reproduction or as queen signals that honestly advertise her fecundity. A recent study suggested that a conserved class of hydrocarbons serve as queen pheromones across three independent origins of eusociality. In bumblebees (Bombus terrestris), pentacosane (C25) was suggested to serve as a queen pheromone. Here, we repeat these studies using a different species of bumblebee (Bombus impatiens) with a more controlled experimental design. Instead of dequeened colonies, we used same-aged, three-worker queenless groups comprising either experienced or naive workers (with/without adult exposure to queen pheromone). We quantified three hydrocarbons (C23, C25 and C27) on the cuticular surfaces of females and tested their effects on the two worker types. Our results indicate differences in responses of naive and experienced workers, genetic effects on worker reproduction, and general effects of hydrocarbons and duration of egg laying on ovary resorption rates. However, we found no evidence to support the theory that a conserved class of hydrocarbons serve as queen pheromones or queen signals in Bombus impatiens.

  20. Postmating changes in cuticular chemistry and visual appearance in Ectatomma tuberculatum queens (Formicidae: Ectatomminae)

    Science.gov (United States)

    Hora, Riviane R.; Ionescu-Hirsh, Armin; Simon, Tovit; Delabie, Jacques; Robert, Jacques; Fresneau, Dominique; Hefetz, Abraham

    2008-01-01

    In the ectatommine ant Ectatomma tuberculatum, the visual appearance of queens changes after mating and ovarian development in that their cuticle turns from shiny to matte. In this study, we have shown that this change seems to be caused by 15-fold accumulation of hydrocarbons, in particular heptacosane that covers the multiple grooves present on the cuticular surface creating a wax coat in mated fully fertile queens. Analyses of the scrapped wax revealed that it is composed largely of heptacosane. Peak-by-peak comparison of the cuticular hydrocarbon (CHC) composition of mated, virgin with developed ovaries and virgin with nondeveloped ovaries revealed significant differences between the queen groups. Although the total amount of the CHC of virgin queens with developed ovaries was not higher than virgin queens that did not have developed ovaries, the composition showed a shift toward the mated queen. While it is possible that the large accumulation of hydrocarbons may give extra physical and chemical protection to queens, we propose that the switch in the relative abundance of heptacosane and nonacosane and perhaps of other components is indicative of being a mating and fertility cue. This is the first report in social insects where external chemical changes are accompanied by changes in visual appearance.

  1. Effect of black raspberry ( Rubus occidentalis L.) extract variation conditioned by cultivar, production site, and fruit maturity stage on colon cancer cell proliferation.

    Science.gov (United States)

    Johnson, Jodee L; Bomser, Joshua A; Scheerens, Joseph C; Giusti, M Monica

    2011-03-01

    Black raspberries have been shown to inhibit multiple stages of oral, esophageal, and colon cancer. The objective of this study was to evaluate how black raspberry extract variability conditioned by horticultural factors affected the antiproliferative activity of 75 black raspberry extracts using an in vitro colon cancer cell model. HT-29 cells grown in 96-well plates were treated with freeze-dried extracts at 0.6 and 1.2 mg of extract/mL of medium. Percent cell growth inhibition for each concentration of the extracts was determined using the sulforhodamine B assay. All extracts significantly inhibited the growth of HT-29 colon cancer cells in a dose-dependent manner. Cell proliferation was significantly influenced by cultivar, production site, and stage of maturity. The lack of correlation between growth inhibition and extract total phenolic and total monomeric anthocyanin assays suggested horticultural parameters influence bioactivity in a complex manner.

  2. Tradition and Imitation in Spenser’s The Faerie Queene

    Directory of Open Access Journals (Sweden)

    Jonathan Griffin

    2013-07-01

    Full Text Available The purpose of this paper is to discuss Spenser’s use of imitation as a literary device in his allegorical epic poem The Faerie Queene, originally published in 1590. The paper begins with a synopsis of Spenser’s general intent behind the poem, as well as his use of the theoretical models of literary excellence proposed by his contemporary Sir Phillip Sidney. The paper then follows Spenser’s reinterpretation of Ariosto, his treatment of Virgil and Ovid, and chronicles his attempts to parody these imperious influences to create an epic that would give synthesis to the poetic tradition to which he belonged with his religious ethic and fervent nationalism, while paying tribute to his monarch, Elizabeth I.

  3. How the Red Queen drives terrestrial mammals to extinction.

    Science.gov (United States)

    Quental, Tiago B; Marshall, Charles R

    2013-07-19

    Most species disappear by the processes of background extinction, yet those processes are poorly understood. We analyzed the evolutionary dynamics of 19 Cenozoic terrestrial mammalian clades with rich fossil records that are now fully extinct or in diversity decline. We find their diversity loss was not just a consequence of "gamblers ruin" but resulted from the evolutionary loss to the Red Queen, a failure to keep pace with a deteriorating environment. Diversity loss is driven equally by both depressed origination rates and elevated extinction rates. Although we find diversity-dependent origination and extinction rates, the diversity of each clade only transiently equaled the implied equilibrium diversity. Thus, the processes that drove diversity loss in terrestrial mammal clades were fundamentally nonequilibrial and overwhelmed diversity-dependent processes.

  4. The recipe: the queen of pragmatics. An Italian case study

    Directory of Open Access Journals (Sweden)

    Leopoldina FORTUNATI

    2015-12-01

    Full Text Available The purpose of this study is to investigate the communicative status and the daily practices of use of the recipe in the broader context of cooking and eating inside the home. My thesis is that the recipe should be regarded as the queen of pragmatics of communication, as recipes are to be found in homes all over the world. I draw on two different research projects: the first study reports upon semi-structured interviews with 137 respondents living in the North East of Italy. The second study presents and discusses the most important categories of meaning that emerged from a content analysis of 398 messages posted on the online cooking forum of the site of Donna Moderna [Modern Woman], the most widely read women’s weekly magazine in Italy.

  5. Asymmetric dispersal and colonization success of Amazonian plant-ants queens.

    Directory of Open Access Journals (Sweden)

    Emilio M Bruna

    Full Text Available BACKGROUND: The dispersal ability of queens is central to understanding ant life-history evolution, and plays a fundamental role in ant population and community dynamics, the maintenance of genetic diversity, and the spread of invasive ants. In tropical ecosystems, species from over 40 genera of ants establish colonies in the stems, hollow thorns, or leaf pouches of specialized plants. However, little is known about the relative dispersal ability of queens competing for access to the same host plants. METHODOLOGY/PRINCIPAL FINDINGS: We used empirical data and inverse modeling--a technique developed by plant ecologists to model seed dispersal--to quantify and compare the dispersal kernels of queens from three Amazonian ant species that compete for access to host-plants. We found that the modal colonization distance of queens varied 8-fold, with the generalist ant species (Crematogaster laevis having a greater modal distance than two specialists (Pheidole minutula, Azteca sp. that use the same host-plants. However, our results also suggest that queens of Azteca sp. have maximal distances that are four-sixteen times greater than those of its competitors. CONCLUSIONS/SIGNIFICANCE: We found large differences between ant species in both the modal and maximal distance ant queens disperse to find vacant seedlings used to found new colonies. These differences could result from interspecific differences in queen body size, and hence wing musculature, or because queens differ in their ability to identify potential host plants while in flight. Our results provide support for one of the necessary conditions underlying several of the hypothesized mechanisms promoting coexistence in tropical plant-ants. They also suggest that for some ant species limited dispersal capability could pose a significant barrier to the rescue of populations in isolated forest fragments. Finally, we demonstrate that inverse models parameterized with field data are an excellent means

  6. Gene expression differences in relation to age and social environment in queen and worker bumble bees.

    Science.gov (United States)

    Lockett, Gabrielle A; Almond, Edward J; Huggins, Timothy J; Parker, Joel D; Bourke, Andrew F G

    2016-05-01

    Eusocial insects provide special insights into the genetic pathways influencing aging because of their long-lived queens and flexible aging schedules. Using qRT-PCR in the primitively eusocial bumble bee Bombus terrestris (Linnaeus), we investigated expression levels of four candidate genes associated with taxonomically widespread age-related pathways (coenzyme Q biosynthesis protein 7, COQ7; DNA methyltransferase 3, Dnmt3; foraging, for; and vitellogenin, vg). In Experiment 1, we tested how expression changes with queen relative age and productivity. We found a significant age-related increase in COQ7 expression in queen ovary. In brain, all four genes showed higher expression with increasing female (queen plus worker) production, with this relationship strengthening as queen age increased, suggesting a link with the positive association of fecundity and longevity found in eusocial insect queens. In Experiment 2, we tested effects of relative age and social environment (worker removal) in foundress queens and effects of age and reproductive status in workers. In this experiment, workerless queens showed significantly higher for expression in brain, as predicted if downregulation of for is associated with the cessation of foraging by foundress queens following worker emergence. Workers showed a significant age-related increase in Dnmt3 expression in fat body, suggesting a novel association between aging and methylation in B. terrestris. Ovary activation was associated with significantly higher vg expression in fat body and, in younger workers, in brain, consistent with vitellogenin's ancestral role in regulating egg production. Overall, our findings reveal a mixture of novel and conserved features in age-related genetic pathways under primitive eusociality.

  7. Black Soybean Seed Coat Extract Prevents Hydrogen Peroxide-Mediated Cell Death via Extracellular Signal-Related Kinase Signalling in HepG2 Cells.

    Science.gov (United States)

    Hashimoto, Naoto; Oki, Tomoyuki; Sasaki, Kazunori; Suda, Ikuo; Okuno, Shigenori

    2015-01-01

    Oxidative stress reduces cell viability and contributes to disease processes. Flavonoids including anthocyanins and proanthocyanidins reportedly induce intracellular antioxidant defence systems. Thus, in this study, we examined the antioxidant effects of a commercial extract from black soybean seed coats (BE), which are rich in anthocyanin and proanthocyanidin, and investigated the associated intracellular mechanisms in HepG2 cells. HepG2 cells treated with hydrogen peroxide (HPO) showed 60% viability, whereas pretreatment with BE-containing media for 2 h ameliorated HPO-mediated cell death by up to 90%. Pretreatment with BE for 2 h partially blocked HPO-mediated activation of ERK in HepG2 cells, and that for 1 h led to a 20% increase in intracellular total protein phosphatase (PP) activity, which is known to deactivate protein kinases. These results indicate that BE prevents HPO-mediated cell damage by inhibiting ERK signalling, potentially via PPs.

  8. Cloning and expression of a queen pheromone-binding protein in the honeybee: an olfactory-specific, developmentally regulated protein.

    Science.gov (United States)

    Danty, E; Briand, L; Michard-Vanhée, C; Perez, V; Arnold, G; Gaudemer, O; Huet, D; Huet, J C; Ouali, C; Masson, C; Pernollet, J C

    1999-09-01

    Odorant-binding proteins (OBPs) are small abundant extracellular proteins thought to participate in perireceptor events of odor-pheromone detection by carrying, deactivating, and/or selecting odor stimuli. The honeybee queen pheromone is known to play a crucial role in colony organization, in addition to drone sex attraction. We identified, for the first time in a social insect, a binding protein called antennal-specific protein 1 (ASP1), which binds at least one of the major queen pheromone components. ASP1 was characterized by cDNA cloning, expression in Pichia pastoris, and pheromone binding. In situ hybridization showed that it is specifically expressed in the auxiliary cell layer of the antennal olfactory sensilla. The ASP1 sequence revealed it as a divergent member of the insect OBP family. The recombinant protein presented the exact characteristics of the native protein, as shown by mass spectrometry, and N-terminal sequencing and exclusion-diffusion chromatography showed that recombinant ASP1 is dimeric. ASP1 interacts with queen pheromone major components, opposite to another putative honeybee OBP, called ASP2. ASP1 biosynthetic accumulation, followed by nondenaturing electrophoresis during development, starts at day 1 before emergence, in concomitance with the functional maturation of olfactory neurons. The isobar ASP1b isoform appears simultaneously to ASP1a in workers, but only at approximately 2 weeks after emergence in drones. Comparison of in vivo and heterologous expressions suggests that the difference between ASP1 isoforms might be because of dimerization, which might play a physiological role in relation with mate attraction.

  9. Queen pheromones modulate DNA methyltransferase activity in bee and ant workers.

    Science.gov (United States)

    Holman, Luke; Trontti, Kalevi; Helanterä, Heikki

    2016-01-01

    DNA methylation is emerging as an important regulator of polyphenism in the social insects. Research has concentrated on differences in methylation between queens and workers, though we hypothesized that methylation is involved in mediating other flexible phenotypes, including pheromone-dependent changes in worker behaviour and physiology. Here, we find that exposure to queen pheromone affects the expression of two DNA methyltransferase genes in Apis mellifera honeybees and in two species of Lasius ants, but not in Bombus terrestris bumblebees. These results suggest that queen pheromones influence the worker methylome, pointing to a novel proximate mechanism for these key social signals.

  10. Effects of occupational exposure to carbon black on peripheral white blood cell counts and lymphocyte subsets

    NARCIS (Netherlands)

    Dai, Yufei; Niu, Yong; Duan, Huawei; Bassig, Bryan A; Ye, Meng; Zhang, Xiao; Meng, Tao; Bin, Ping; Jia, Xiaowei; Shen, Meili; Zhang, Rong; Hu, Wei; Yang, Xiaofa; Vermeulen, Roel; Silverman, Debra; Rothman, Nathaniel; Lan, Qing; Yu, Shanfa; Zheng, Yuxin

    2016-01-01

    The International Agency for Research on Cancer has classified carbon black (CB) as a possible (Group 2B) human carcinogen. Given that most CB manufacturing processes result in the emission of various types of chemicals, it is uncertain if the adverse health effects that have been observed in CB-exp

  11. Allergic manifestation by black gram (Vigna mungo) proteins in allergic patients, BALB/c mice and RBL-2H3 cells.

    Science.gov (United States)

    Verma, Alok Kumar; Kumar, Sandeep; Sharma, Akanksha; Kumar, Dinesh; Roy, Ruchi; Gupta, Rinkesh Kumar; Chaudhari, Bhushan P; Giridhar, B H; Das, Mukul; Dwivedi, Premendra D

    2014-11-01

    The prevalence of black gram (Vigna mungo) induced allergic reactions are reported from several parts of the world including Asia and Australia. But, a thorough exploration of the allergic reactions induced by black gram proteins is still lacking. Therefore, efforts have been made to explore black gram allergy using in vivo and in vitro approaches. In this study, Simulated Gastric Fluid (SGF) assay and IgE immunoblotting were carried out to identify clinically relevant allergens of black gram. BALB/c mice and RBL-2H3 cells were used for elucidation of allergenic reactions of black gram proteins. Further, this study was extended to screen black gram sensitive patients among nasobronchial allergic patients on the basis of clinical history, skin prick test (SPT), specific IgE levels and IgE immunoblotting. Enhanced levels of specific IgE, IgG1/IgG2a (p < 0.05), histamine (p < 0.05), clinical symptoms, pathological indications in the lungs, intestine and spleen were evident in black gram sensitized BALB/c mice. Moreover, the expression of Th2 cytokine transcripts and GATA-3/T-bet ratio was found enhanced in the treated group. In vitro studies on RBL-2H3 cells,showed increased release of β-hexosaminidase (p < 0.05), histamine (p < 0.05), cysteinyl leukotriene (p<0.05) and prostaglandin D2 (p < 0.05). Further, 8.5% of screened patients were found allergic to black gram and concomitant sensitization with other allergens has shown the possibility of further enhancement in allergenic problem. Conclusively, the present study suggested that black gram consumption may be responsible for inducing immediate type of allergic sensitization in susceptible subjects.

  12. Distribution of acid phosphatases in the hypopharyngeal glands from workers, queens and males of a Brazilian stingless bee Scaptotrigona postica Latreille: an ultrastructural cytochemical study.

    Science.gov (United States)

    Costa, R A; da Cruz-Landim, C

    2001-01-01

    The present study reports the localization of acid phosphatase in the hypopharyngeal gland cells from workers (newly-emerged, nurse and forager), queens (newly-emerged and laying) and males (newly-emerged and mature for mating) of the Brazilian stingless bee, Scaptotrigona postica. The phosphatase activity varied in intensity and localization depending on the individual class, physiological age and the substrate used. In newly-emerged workers, the phosphatase-positive sites suggest the involvement of the enzyme with cellular differentiation that occurs in the presecretory phase, in nurse workers with protein synthesis and in forager workers with changes in cellular activity or glandular regression. In males mature for mating and laying queens, the positive sites are related to secretory activity, showing that the gland maintains some activity in spite of the regressive aspect. Of the substrates used, beta-glycerophosphate gave the least specific localization.

  13. 2006 Maryland Department of Natural Resources Lidar: Caroline, Kent and Queen Anne Counties

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Maryland Department of Natural Resources requested the collection of LIDAR data over Kent, Queen Anne and Caroline Counties, MD. In response, EarthData acquired the...

  14. Ant Queen Egg-Marking Signals: Matching Deceptive Laboratory Simplicity with Natural Complexity

    DEFF Research Database (Denmark)

    van Zweden, Jelle Stijn; Heinze, Jürgen; Boomsma, Jacobus Jan

    2009-01-01

    Background Experiments under controlled laboratory conditions can produce decisive evidence for testing biological hypotheses, provided they are representative of the more complex natural conditions. However, whether this requirement is fulfilled is seldom tested explicitly. Here we provide a lab....../field comparison to investigate the identity of an egg-marking signal of ant queens. Our study was based on ant workers resolving conflict over male production by destroying each other's eggs, but leaving queen eggs unharmed. For this, the workers need a proximate cue to discriminate between the two egg types...... that this compound by itself is not the natural queen egg-marking pheromone. We subsequently investigated the overall differences of entire chemical profiles of eggs, and found that queen-laid eggs in field colonies are more distinct from worker-laid eggs than in lab colonies, have more variation in profiles...

  15. Ant queens adjust egg fertilization to benefit from both sexual and asexual reproduction.

    Science.gov (United States)

    Aron, S; Timmermans, I; Pearcy, M

    2011-08-23

    An enduring problem in evolutionary biology is the near ubiquity of sexual reproduction despite the inherent cost of transmitting only half the parent's genes to progeny. Queens of some ant species circumvent this cost by using selectively both sexual reproduction and parthenogenesis: workers arise from fertilized eggs, while new queens are produced by parthenogenesis. We show that queens of the ant Cataglyphis cursor maximize the transmission rate of their genes by regulating the proportion of fertilized and parthenogenetic eggs laid over time. Parthenogenetic offspring are produced in early spring, when workers raise the brood into sexuals. After the mating period, queens lay mostly fertilized eggs that will be reared as the non-reproductive caste.

  16. Fishery-independent Surveys of Queen Conch in St. Croix 2010-2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We examined queen conch populations on the northeastern coast of St. Croix, U.S. Virgin Islands, using a radial survey sampling technique with sample sites...

  17. Mimicry of queen Dufour's gland secretions by workers of Apis mellifera scutellata and A. m. capensis

    Science.gov (United States)

    Sole, Catherine; Kryger, Per; Hefetz, Abraham; Katzav-Gozansky, Tamar; Crewe, Robin

    2002-10-01

    The development of the Dufour's gland of workers of the two honey bee races Apis mellifera scutellata and A. m. capensis was measured. The Dufour's glands of A. m. capensis workers were longer and increased in length more rapidly than the glands of workers of A. m. scutellata at comparable ages. Analysis of the Dufour's gland secretions of workers and queens of both races revealed that there were caste and racial differences. Secretions of queenright A. m. scutellata workers were dominated by a series of long-chain hydrocarbons. In contrast the secretions of the A. m. capensis workers both under queenright and queenless conditions were a mixture of hydrocarbons and wax-type esters, as were those of queens. Multivariate analysis of the secretion profiles indicated that laying workers of both races mimic queens. The secretions of the A. m. capensis laying workers mimicked queen secretions most closely, enabling them to act as successful social parasites.

  18. Chemopreventive activity of ellagitannins and their derivatives from black raspberry seeds on HT-29 colon cancer cells.

    Science.gov (United States)

    Cho, Hyunnho; Jung, Hana; Lee, Heejae; Yi, Hae Chang; Kwak, Ho-kyung; Hwang, Keum Taek

    2015-05-01

    Black raspberry (BRB) seeds are a major waste product after fruit processing. The seeds are abundant in ellagitannins (ET), a class of hydrolysable tannins, which are hydrolyzed to ellagic acid (EA) and further metabolized to urolithin A (UA) and urolithin B (UB), known to be bioavailable in the colon and the prostate. In this study, the anti-cancer activities of these compounds were evaluated on HT-29 colon cancer cells. ET, EA, UA and UB inhibited the proliferation of the cancer cells. EA caused a slight, but significant cell cycle arrest at the G1 phase, and urolithins caused cell cycle arrest at the G2/M phase and upregulated p21 expression. Apoptotic cells were detected by Annexin V-FITC/PI assay when treated with the compounds. Disruption in mitochondrial membrane potential and activation of caspases 8 and 9 suggest that both extrinsic and intrinsic apoptotic pathways may be involved. Activation of caspase 3 and cleavage of PARP further confirmed the induction of the apoptosis. ET, EA, UA and UB showed anti-cancer activity by arresting the cell cycle and inducing apoptosis on HT-29 human colon cancer cells. This study suggests that the BRB seeds could be a potential source of anti-cancer ET.

  19. Vertical transmission of honey bee viruses in a Belgian queen breeding program

    OpenAIRE

    Ravoet, Jorgen; De Smet, Lina; Wenseleers, Tom; de Graaf, Dirk

    2015-01-01

    Background The Member States of European Union are encouraged to improve the general conditions for the production and marketing of apicultural products. In Belgium, programmes on the restocking of honey bee hives have run for many years. Overall, the success ratio of this queen breeding programme has been only around 50%. To tackle this low efficacy, we organized sanitary controls of the breeding queens in 2012 and 2014. Results We found a high quantity of viruses, with more than 75% of the ...

  20. The Queens' estates: fiscal properties and royal policy ( 9th -10th centuries

    Directory of Open Access Journals (Sweden)

    Tiziana Lazzari (a cura di

    2012-10-01

    Full Text Available The special condition of the queens of italic Kingdom during the 9th and 10th centuries is exemplified by the title of consors regni and by the exceptionally copious dowers bestowed to them when compared to those entrusted to other European queens. Through the accurate reconstruction of these dowries, composed of royal fiscal assets, this anomaly is explained within the context of specific royal governmental strategies.

  1. Black silicon with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io;

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by mask-less reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Black bus-bars were realized by oxidized copper resulting in reflectance below 3% in the entire visible wavelength range. The combination of these two technologies may result in aesthetic, all-black panels based on conventional, front-contacted solar cells...

  2. Performance of Africanized honeybee colonies settled by queens selected for different traits

    Directory of Open Access Journals (Sweden)

    Tânia Patrícia Schafaschek

    2016-01-01

    Full Text Available We evaluated varroa infestation and the performance of Africanized honeybee colonies with queens selected for honey and royal jelly production, and also unselected queens, correlating with climatic variables. In Campo Alegre, Santa Catarina State, Brazil, the experiment I used 10 Langstroth hives and in Mafra, Santa Catarina State, Brazil, the experiment II was performed with 15 Schenk hives. A mapping in areas of sealed and unsealed brood, honey and pollen was carried out on days zero, 45 and 90 days after the introduction of the queen. In the experiment I, there was interaction between the type of queen selection and the evaluation period for areas of sealed brood, honey, and total stored food. The group selected for royal jelly production presented larger sealed brood area and smaller honey area at 90 days. Varroa infestation was lower (p < 0.05 at 90 days. The type of queen selection and the evaluation period influenced the sealed brood area, the total brood and the total area occupied in the colony. The high relative humidity caused greater honey storage for the local group. The different groups of queens presented different behavior according to the environment in which they are settled.

  3. Combined neonicotinoid pesticide and parasite stress alter honeybee queens' physiology and survival.

    Science.gov (United States)

    Dussaubat, Claudia; Maisonnasse, Alban; Crauser, Didier; Tchamitchian, Sylvie; Bonnet, Marc; Cousin, Marianne; Kretzschmar, André; Brunet, Jean-Luc; Le Conte, Yves

    2016-01-01

    Honeybee colony survival strongly relies on the queen to overcome worker losses exposed to combined stressors like pesticides and parasites. Queen's capacity to withstand these stressors is however very little known. The effects of the common neonicotinoid pesticide imidacloprid in a chronic and sublethal exposure together with the wide distributed parasite Nosema ceranae have therefore been investigated on queen's physiology and survivorship in laboratory and field conditions. Early physiological changes were observed on queens, particularly the increase of enzyme activities (catalase [CAT] and glutathione-S-transferase [GST] in the heads) related to protective responses to xenobiotics and oxidative stress against pesticide and parasite alone or combined. Stressors also alter the activity of two other enzymes (carboxylesterase alpha [CaE α] and carboxylesterase para [CaE p] in the midguts) involved in metabolic and detoxification functions. Furthermore, single and combined effects of pesticide and parasite decrease survivorship of queens introduced into mating hives for three months. Because colony demographic regulation relies on queen's fertility, the compromise of its physiology and life can seriously menace colony survival under pressure of combined stressors.

  4. Termite queens close the sperm gates of eggs to switch from sexual to asexual reproduction.

    Science.gov (United States)

    Yashiro, Toshihisa; Matsuura, Kenji

    2014-12-02

    Males and females are in conflict over genetic transmission in the evolution of parthenogenesis, because it enhances female reproductive output but deprives the males' genetic contribution. For males, any trait that coerces females into sexual reproduction should increase their fitness. However, in the termite Reticulitermes speratus, queens produce their replacements (neotenic queens) parthenogenetically while using normal sexual reproduction to produce other colony members. Here, we show that termite queens produce parthenogenetic offspring in the presence of kings by closing the micropyles (sperm gates; i.e., openings for sperm entry) of their eggs. Our field survey showed that termite eggs show large variation in numbers of micropyles, with some having none. Microsatellite analysis showed that embryos of micropyleless eggs develop parthenogenetically, whereas those of eggs with micropyles are fertilized and develop sexually. Surveys of eggs among queens of different age groups showed that queens begin to lay micropyleless eggs when they are older and thus, need to produce their replacements parthenogenetically. In addition, we found clear seasonality in new neotenic queen differentiation and micropyleless egg production. This micropyle-dependent parthenogenesis is the first identification, to our knowledge, of the mechanism through which females control egg fertilization over time in diploid animals, implying a novel route of the evolution of parthenogenesis in favor of female interests without interference from males.

  5. Black Tea Extract and Its Theaflavin Derivatives Inhibit the Growth of Periodontopathogens and Modulate Interleukin-8 and β-Defensin Secretion in Oral Epithelial Cells.

    Science.gov (United States)

    Lombardo Bedran, Telma Blanca; Morin, Marie-Pierre; Palomari Spolidorio, Denise; Grenier, Daniel

    2015-01-01

    Over the years, several studies have brought evidence suggesting that tea polyphenols, mostly from green tea, may have oral health benefits. Since few data are available concerning the beneficial properties of black tea and its theaflavin derivatives against periodontal disease, the objective of this study was to investigate their antibacterial activity as well as their ability to modulate interleukin-8 and human β-defensin (hBD) secretion in oral epithelial cells. Among the periodontopathogenic bacteria tested, Porphyromonas gingivalis was found to be highly susceptible to the black tea extract and theaflavins. Moreover, our data indicated that the black tea extract, theaflavin and theaflavin-3,3'-digallate can potentiate the antibacterial effect of metronidazole and tetracycline against P. gingivalis. Using lipopolysaccharide-stimulated oral epithelial cells, the black tea extract (100 μg/ml), as well as theaflavin and theaflavin-3,3'-digallate (50 μg/ml) reduced interleukin-8 (IL-8) secretion by 85%, 79%, and 86%, respectively, thus suggesting an anti-inflammatory property. The ability of the black tea extract and its theaflavin derivatives to induce the secretion of the antimicrobial peptides hBD-1, hBD-2 and hBD-4 by oral epithelial cells was then evaluated. Our results showed that the black tea extract as well as theaflavin-3,3'-digallate were able to increase the secretion of the three hBDs. In conclusion, the ability of a black tea extract and theaflavins to exert antibacterial activity against major periodontopathogens, to attenuate the secretion of IL-8, and to induce hBD secretion in oral epithelial cells suggest that these components may have a beneficial effect against periodontal disease.

  6. Colony Failure Linked to Low Sperm Viability in Honey Bee (Apis mellifera Queens and an Exploration of Potential Causative Factors.

    Directory of Open Access Journals (Sweden)

    Jeffery S Pettis

    Full Text Available Queen health is closely linked to colony performance in honey bees as a single queen is normally responsible for all egg laying and brood production within the colony. In the U. S. in recent years, queens have been failing at a high rate; with 50% or greater of queens replaced in colonies within 6 months when historically a queen might live one to two years. This high rate of queen failure coincides with the high mortality rates of colonies in the US, some years with >50% of colonies dying. In the current study, surveys of sperm viability in US queens were made to determine if sperm viability plays a role in queen or colony failure. Wide variation was observed in sperm viability from four sets of queens removed from colonies that beekeepers rated as in good health (n = 12; average viability = 92%, were replacing as part of normal management (n = 28; 57%, or where rated as failing (n = 18 and 19; 54% and 55%. Two additional paired set of queens showed a statistically significant difference in viability between colonies rated by the beekeeper as failing or in good health from the same apiaries. Queens removed from colonies rated in good health averaged high viability (ca. 85% while those rated as failing or in poor health had significantly lower viability (ca. 50%. Thus low sperm viability was indicative of, or linked to, colony performance. To explore the source of low sperm viability, six commercial queen breeders were surveyed and wide variation in viability (range 60-90% was documented between breeders. This variability could originate from the drones the queens mate with or temperature extremes that queens are exposed to during shipment. The role of shipping temperature as a possible explanation for low sperm viability was explored. We documented that during shipment queens are exposed to temperature spikes ( 40°C and these spikes can kill 50% or more of the sperm stored in queen spermathecae in live queens. Clearly low sperm viability is

  7. Colony Failure Linked to Low Sperm Viability in Honey Bee (Apis mellifera) Queens and an Exploration of Potential Causative Factors.

    Science.gov (United States)

    Pettis, Jeffery S; Rice, Nathan; Joselow, Katie; vanEngelsdorp, Dennis; Chaimanee, Veeranan

    2016-01-01

    Queen health is closely linked to colony performance in honey bees as a single queen is normally responsible for all egg laying and brood production within the colony. In the U. S. in recent years, queens have been failing at a high rate; with 50% or greater of queens replaced in colonies within 6 months when historically a queen might live one to two years. This high rate of queen failure coincides with the high mortality rates of colonies in the US, some years with >50% of colonies dying. In the current study, surveys of sperm viability in US queens were made to determine if sperm viability plays a role in queen or colony failure. Wide variation was observed in sperm viability from four sets of queens removed from colonies that beekeepers rated as in good health (n = 12; average viability = 92%), were replacing as part of normal management (n = 28; 57%), or where rated as failing (n = 18 and 19; 54% and 55%). Two additional paired set of queens showed a statistically significant difference in viability between colonies rated by the beekeeper as failing or in good health from the same apiaries. Queens removed from colonies rated in good health averaged high viability (ca. 85%) while those rated as failing or in poor health had significantly lower viability (ca. 50%). Thus low sperm viability was indicative of, or linked to, colony performance. To explore the source of low sperm viability, six commercial queen breeders were surveyed and wide variation in viability (range 60-90%) was documented between breeders. This variability could originate from the drones the queens mate with or temperature extremes that queens are exposed to during shipment. The role of shipping temperature as a possible explanation for low sperm viability was explored. We documented that during shipment queens are exposed to temperature spikes ( 40°C) and these spikes can kill 50% or more of the sperm stored in queen spermathecae in live queens. Clearly low sperm viability is linked to

  8. Colony Failure Linked to Low Sperm Viability in Honey Bee (Apis mellifera) Queens and an Exploration of Potential Causative Factors

    Science.gov (United States)

    Pettis, Jeffery S.; Rice, Nathan; Joselow, Katie; vanEngelsdorp, Dennis; Chaimanee, Veeranan

    2016-01-01

    Queen health is closely linked to colony performance in honey bees as a single queen is normally responsible for all egg laying and brood production within the colony. In the U. S. in recent years, queens have been failing at a high rate; with 50% or greater of queens replaced in colonies within 6 months when historically a queen might live one to two years. This high rate of queen failure coincides with the high mortality rates of colonies in the US, some years with >50% of colonies dying. In the current study, surveys of sperm viability in US queens were made to determine if sperm viability plays a role in queen or colony failure. Wide variation was observed in sperm viability from four sets of queens removed from colonies that beekeepers rated as in good health (n = 12; average viability = 92%), were replacing as part of normal management (n = 28; 57%), or where rated as failing (n = 18 and 19; 54% and 55%). Two additional paired set of queens showed a statistically significant difference in viability between colonies rated by the beekeeper as failing or in good health from the same apiaries. Queens removed from colonies rated in good health averaged high viability (ca. 85%) while those rated as failing or in poor health had significantly lower viability (ca. 50%). Thus low sperm viability was indicative of, or linked to, colony performance. To explore the source of low sperm viability, six commercial queen breeders were surveyed and wide variation in viability (range 60–90%) was documented between breeders. This variability could originate from the drones the queens mate with or temperature extremes that queens are exposed to during shipment. The role of shipping temperature as a possible explanation for low sperm viability was explored. We documented that during shipment queens are exposed to temperature spikes ( 40°C) and these spikes can kill 50% or more of the sperm stored in queen spermathecae in live queens. Clearly low sperm viability is linked to

  9. The use of quantitative PCR to detect Felis catus papillomavirus type 2 DNA from a high proportion of queens and their kittens.

    Science.gov (United States)

    Thomson, N A; Dunowska, M; Munday, J S

    2015-02-25

    Squamous cell carcinomas are common feline skin cancers that have been associated with infection with Felis catus papillomavirus type 2 (FcaPV-2). Currently, little is known about the epidemiology of FcaPV-2 infection. The aim of this study was to develop a real-time PCR assay to quantify FcaPV-2 DNA in plucked hairs and skin swabs from 11 healthy breeding queens and their kittens. Samples were taken prior to kittening and then 2, 7 and 28 days after kittening to determine the age at which the kittens were first exposed to the virus. FcaPV-2 DNA was amplified from all of the queens and from 91% of the kittens at 2 days of age. There was a wide range in the quantity of FcaPV-2 DNA detected, from 1 to 92,520 copies per swab, and from 0.01 to 234 copies per copy of reference gene DNA in the hair plucks. The quantity of FcaPV-2 DNA detected in samples collected from the kittens was strongly correlated to that of their respective queens and the mean viral DNA load was similar for cats within a household but varied significantly between households. This is the first time that quantitative PCR has been used to detect FcaPV-2 DNA and the results suggest that the virus is ubiquitous but there is a wide variation of viral DNA loads. Kittens appear to be exposed to FcaPV-2 early in life, presumably from direct contact with their queen. These results are important when determining if FcaPV-2 infection of cats is preventable.

  10. Acetylcholinesterase characteristics of termite queen exposed to anticholinesterase compounds.

    Science.gov (United States)

    Bhattacharya, S; Ghosh, P; Ghosh, S; Ghosh, N; Bhattacharya, B; Halder, P

    1992-06-01

    A regional profile of AChE activity was noted in the Indian termite queen Odontotermes redemanni with the head recording the higher and body the lower range of activity. The enzyme characteristics such as substrate and temperature optima were more or less similar while pH requirement for optimum AChE activity varied from 7.0 to 7.6 In vitro inhibition of head and body AChE was studied using pure and commercial anticholinesterase compounds. Interestingly, the commercial formulations like Metacid-50 and Carbaryl are potent enough at 1 x 10(-8) M to produce 50% in vitro inhibition of AChE of head and body regions within 15 min of preincubation. A 20 min of preincubation (t0.5) was necessary to record 50% in vitro inhibition of AChE with known and pure anticholinesterase compounds such as DFP (3.5 x 10(-10) M) and physostigmine (3.6 x 10(-10) M). It is surmised that (a) the response of the head and body AChE to the commercial formulations of the insecticides may be used as a reliable and sensitive bioindicator of pesticidal contamination of the terrestrial environment and (b) termite control may be successfully done with the application of organophosphate or carbamate compounds.

  11. Swan Queen, shipping, and boundary regulation in fandom

    Directory of Open Access Journals (Sweden)

    Victoria M. Gonzalez

    2016-09-01

    Full Text Available There are a number of fan activities and practices that are subject to regulation. The mechanisms of regulation in shipping, however, are not always clear. Shipping, the fan activity of romantically pairing two fictional characters, has become a popular and contentious facet of fan interaction. The case that will be examined in this article is that of the Swan Queen ship, which pairs two female characters from Once Upon a Time (2011–. The lengths that fans have gone to support and promote this ship led to rather intense discussion and infighting among members of the Once Upon a Time fandom. I utilize comments and posts made on Tumblr to examine the mechanisms that dictate inclusion and exclusion in shipper communities. In doing so, I hope to identify the kinds of shipper activities that are subject to regulation and the kinds of boundaries that this regulation establishes. Shipping is dictated not only by fans' imaginations but also by boundaries that are performed and regulated on digital forums.

  12. A look inside the mechanistic black box: Are red blood cells the critical effectors of RRx-001 cytotoxicity?

    Science.gov (United States)

    Cabrales, Pedro; Scicinski, Jan; Reid, Tony; Kuypers, Frans; Larkin, Sandra; Fens, Marcel; Oronsky, Arnold; Oronsky, Bryan

    2016-07-01

    The therapeutic potential of epi-immunotherapeutic anticancer agent RRx-001 in cancer has been validated with preclinical and clinical studies, since RRx-001 has successfully completed a phase 1 trial and multiple single-agent and combination phase 2 trials with preliminary evidence of promising activity are underway. Previous experimental work has implicated diverse anticancer mechanisms such as oxidative stress, ATP and NADPH depletion, anti-angiogenesis and epigenetic modulation in the overall antitumor effect of RRx-001. The hypothesis of this study was that the RRx-001 red blood cells are the essential and de facto intermediaries responsible for the reprograming of tumor behavior via transfer of their intracellular and membrane contents. To test this hypothesis, and thereby resolve the "black box" incompleteness in the continuity of the mechanism, the fate of red blood cells incubated with RRx-001 was explored in vitro and in vivo both in healthy animals and in tumor-bearing mice. The collective results establish that RRx-001-derivatized red blood cells are the critical "missing links" to explain the specificity and anticancer activity of RRx-001, including its immunomodulatory effects on tumor-associated macrophages. These experimental results delineate a novel erythrocyte-based mechanism without precedent in the annals of oncology and open the door to rational combination strategies with RRx-001 both in cancer therapy and beyond, particularly in disease states that affect red blood cell and vascular function such as malaria, leishmaniasis, sickle-cell disease and hemorrhagic shock.

  13. Black Droplets

    CERN Document Server

    Santos, Jorge E

    2014-01-01

    Black droplets and black funnels are gravitational duals to states of a large N, strongly coupled CFT on a fixed black hole background. We numerically construct black droplets corresponding to a CFT on a Schwarzchild background with finite asymptotic temperature. We find two branches of such droplet solutions which meet at a turning point. Our results suggest that the equilibrium black droplet solution does not exist, which would imply that the Hartle-Hawking state in this system is dual to the black funnel constructed in \\cite{Santos:2012he}. We also compute the holographic stress energy tensor and match its asymptotic behaviour to perturbation theory.

  14. Comparative study of the growth-inhibitory and apoptosis-inducing activities of black tea theaflavins and green tea catechin on murine myeloid leukemia cells.

    Science.gov (United States)

    Lung, Hong-Lok; Ip, Wai-Ki; Chen, Zhen-Yu; Mak, Nai-Ki; Leung, Kwok-Nam

    2004-03-01

    Among the black tea polyphenols, theaflavins are generally considered to be the more effective components for the inhibition of carcinogenesis. In this study, we attempted to compare the growth-inhibitory and apoptosis-inducing activities of the four black tea theaflavins (TF-1, TF-2A, TF-2B and TF-3) with the major green tea catechin epigallocatechin-3-gallate (EGCG) on the murine myeloid leukemia WEHI-3B JCS cells. All the four black tea theaflavins were shown to exert potent anti-proliferative and cytotoxic effects on the leukemia WEHI-3B JCS cells in a dose-dependent manner. The observed anti-proliferative and cytotoxic effects were in the following order of potency: EGCG > TF-2B > TF-3 > TF-2A > TF-1. In addition, all theaflavins were capable of inducing apoptosis in the leukemia WEHI-3B JCS cells. Among the four theaflavins tested, TF-2B and TF-3 were found to be slightly more potent in inducing apoptosis of the WEHI-3B JCS cells than that of TF-2A and TF-1 but were comparable to the major green tea epicatechin EGCG. More interestingly, both TF-2B and TF-3 were found to be much more effective than TF-1 and TF-2B in reducing both the in vitro clonogenicity and in vivo tumorigenicity of the WEHI-3B JCS cells, suggesting that these two black tea theaflavins might represent potential candidates for the treatment of some forms of leukemia.

  15. Ultrastructure of germ cells, Sertoli cells and mitochondria during spermatogenesis in mature testis of the Chinese Taihang black goats (Capra hircus).

    Science.gov (United States)

    Shi, Liguang; Xun, Wenjuan; Zhou, Hanlin; Hou, Guanyu; Yue, Wenbin; Zhang, Chunxiang; Ren, Youshe; Yang, Rujie

    2013-07-01

    The objective of this study was to describe the ultrastructure of germ cells, Sertoli cells and mitochondria in mature testis of the Chinese Taihang black goat. The characteristics of germ cell nucleus and mitochondria changing during spermatogenesis were investigated by transmission electron microscopy (TEM). The results showed that the spermatogonium was elliptical, and its nucleus was about 4-5 μm. The round mitochondria can be observed throughout the cytoplasm around the nucleus. Small patches of heterochromatin were distributed throughout the nucleus. Spermatocyte was oval-shaped with a nucleus of about 4-4.5 μm in diameter. The heterochromatin began to attach to the inner surface of the nuclear membrane. Spermatid was about 4 μm and oval in shape. Its nucleus was oval or round and approximately 2-3 μm in diameter. The borderline between nucleus membrane and karyoplasm was distinct. During spermiogenesis, spermatid nucleus was condensed and elongated, and chromatin reached the highest condensation in the mature spermatozoon. The mid-piece was surrounded by mitochondria at the neck region. The sperm tail showed the typical "9+2″ structure, contained axoneme and central singlet microtubules. The nuclei of the Sertoli cells were irregular shaped and showed indentations in the membrane. In the mature testes of goat bucks, abundant mitochondria were around the germ cells and Sertoli cells. The scattered mitochondria were aggregated around the base of the flagellum (axoneme) during the spermatid differentiation stage. In conclusion, the present study showed that the spermatogenic process of Taihang black goat followed the pattern of mammals with some specific.

  16. Colony insularity through queen control on worker social motivation in ants.

    Science.gov (United States)

    Boulay, Raphaël; Katzav-Gozansky, Tamar; Vander Meer, Robert K; Hefetz, Abraham

    2003-05-01

    We investigated the relative contribution of the queen and workers to colony nestmate recognition cues and on colony insularity in the Carpenter ant Camponotus fellah. Workers were either individually isolated, preventing contact with both queen and workers (colonial deprived, CD), kept in queenless groups, allowing only worker-worker interactions (queen deprived, QD) or in queenright (QR) groups. Two weeks post-separation QD and QR workers were amicable towards each other but both rejected their CD nestmates, which suggests that the queen does not measurably influence the colony recognition cues. By contrast, aggression between QD and QR workers from the same original colony was apparent only after six months of separation. This clearly demonstrates the power of the Gestalt and indicates that the queen is not a dominant contributor to the nestmate recognition cues in this species. Aggression between nestmates was correlated with a greater hydrocarbon (HC) profile divergence for CD than for QD and QR workers, supporting the importance of worker-worker interactions in maintaining the colony Gestalt odour. While the queen does not significantly influence nestmate recognition cues, she does influence colony insularity since within 3 days QD (queenless for six months) workers from different colony origins merged to form a single queenless colony. By contrast, the corresponding QR colonies maintained their territoriality and did not merge. The originally divergent cuticular and postpharyngeal gland HC profiles became congruent following the merger. Therefore, while workers supply and blend the recognition signal, the queen affects worker-worker interaction by reducing social motivation and tolerance of alien conspecifics.

  17. Elevated red blood cell 2,3-diphosphoglycerate levels in black blood donors.

    Science.gov (United States)

    Wallas, C H

    1978-01-01

    Mean levels of 2,3-diphosphoglycerate (DPG) were significantly increased in erythrocytes (RBC) from 43 nonanemic black blood donors (4.80 +/- 0.06 micromoles/l RBC) compared with 22 white donors 4.47 +/- 0.08 micromoles/l RBCs from eight of the 12 black donors with DPG levels greater than 5 micromoles/l RBC. Although a potentially hemolytic disorder could be defined in four (AS hemoglobin, beta-Thalassemia minor, G6PD deficiency), reticulocyte counts were normal. However, when RBCs from the subgroup were compared to RBCs from an additional 25 unselected white donors, the following suggested an abnormally large population of young RBCs in the subgroup: 1) normal or elevated RBC-ATP with normal serum phosphate level; 2) significantly increased activities of RBC age-dependent enzymes hexokinase (p less than 0.02), pyruvate kinase (p less than 0.05), and glutamicoxaloacetic transaminase (p less than 0.01), with normal activity of phosphoglycerate kinase, an age-independent enzyme; 3) decreased dense (older) RBCs as determined by sedimentation in phthalate esters. Since DPG is increased in young RBCs and falls as the RBC ages, loss of older relatively DPG depleted RBCs due to shortened survival could account for the elevated DPG levels seen in the subgroup.

  18. The effect of queen pheromone status on Varroa mite removal from honey bee colonies with different grooming ability.

    Science.gov (United States)

    Bahreini, Rassol; Currie, Robert W

    2015-07-01

    The objective of this study was to assess the effects of honey bees (Apis mellifera L.) with different grooming ability and queen pheromone status on mortality rates of Varroa mites (Varroa destructor Anderson and Trueman), mite damage, and mortality rates of honey bees. Twenty-four small queenless colonies containing either stock selected for high rates of mite removal (n = 12) or unselected stock (n = 12) were maintained under constant darkness at 5 °C. Colonies were randomly assigned to be treated with one of three queen pheromone status treatments: (1) caged, mated queen, (2) a synthetic queen mandibular pheromone lure (QMP), or (3) queenless with no queen substitute. The results showed overall mite mortality rate was greater in stock selected for grooming than in unselected stock. There was a short term transitory increase in bee mortality rates in selected stock when compared to unselected stock. The presence of queen pheromone from either caged, mated queens or QMP enhanced mite removal from clusters of bees relative to queenless colonies over short periods of time and increased the variation in mite mortality over time relative to colonies without queen pheromone, but did not affect the proportion of damaged mites. The effects of source of bees on mite damage varied with time but damage to mites was not reliably related to mite mortality. In conclusion, this study showed differential mite removal of different stocks was possible under low temperature. Queen status should be considered when designing experiments using bioassays for grooming response.

  19. High-Performance Black Multicrystalline Silicon Solar Cells by a Highly Simplified Metal-Catalyzed Chemical Etching Method

    KAUST Repository

    Ying, Zhiqin

    2016-05-20

    A wet-chemical surface texturing technique, including a two-step metal-catalyzed chemical etching (MCCE) and an extra alkaline treatment, has been proven as an efficient way to fabricate high-efficiency black multicrystalline (mc) silicon solar cells, whereas it is limited by the production capacity and the cost cutting due to the complicated process. Here, we demonstrated that with careful control of the composition in etching solution, low-aspect-ratio bowl-like nanostructures with atomically smooth surfaces could be directly achieved by improved one-step MCCE and with no posttreatment, like alkali solution. The doublet surface texture of implementing this nanobowl structure upon the industrialized acidic-textured surface showed concurrent improvement in optical and electrical properties for realizing 18.23% efficiency mc-Si solar cells (156 mm × 156 mm), which is sufficiently higher than 17.7% of the solely acidic-textured cells in the same batch. The one-step MCCE method demonstrated in this study may provide a cost-effective way to manufacture high-performance mc-Si solar cells for the present photovoltaic industry. © 2016 IEEE.

  20. Black psyllium

    Science.gov (United States)

    Black psyllium is a weed that grows aggressively throughout the world. The plant was spread with the ... to make medicine. Be careful not to confuse black psyllium with other forms of psyllium including blond ...

  1. Myth and memory in the “queen of dreams”

    Directory of Open Access Journals (Sweden)

    Gloria Montero

    2009-06-01

    Full Text Available Aristotle said that where the historian tells us what took place, the poet tells us how it came about. More recently, Gore Vidal defined ‘memoir’ as how one remembers one’s own life as distinct from an autobiography which is history, requiring research into dates and facts which must be double-checked. Memory and Myth play an important role in memoir, allowing the writer to incorporate the real underpinnings of a story that has been lived through rather than simply the account of a sequence of actual events. It might also be argued that the patina of memory that coats the ‘memoir’, as distinct from autobiography, might indeed add its own dimension, taking the account of something very real into a more surreal space. What I call my Rora stories published in Spanish under the title Todas Esas Guerras-- All Those Wars – have never appeared as a collection in English but have been published separately in literary journals. These stories, the very closest I think I will ever come to writing autobiography, grew out of a need to explore my own background – so fragmented in terms of geography, history and culture – at a time when, as a writer, I felt the desperate need to find out exactly who this multicultural person with her mixed baggage might be. The Queen of Dreams, one of the stories in the collection, uses the memory of the child Rora as she attempts to understand the drama and magic of sexuality and love in a grown-up, intolerant world at war. While the story explores the child’s personal history, it also reflects the psyche of Australia at that particular moment.

  2. Organic maturation and thermal history of Queen Charlotte Islands

    Energy Technology Data Exchange (ETDEWEB)

    Bustin, R.M.; Vellutini, D. (Univ. of British Columbia, Vancouver (Canada))

    1989-09-01

    The level of organic maturation and thermal history of Mesozoic and Tertiary strata of the Queen Charlotte Islands have been determined with vitrinite reflectance (R{sub 0}), numerical modeling (modified Arrhenius model), and Rock-Eval Pyrolysis. The level of organic maturation increases from northern Graham to southern Moresby Island, which primarily reflects high heat flow resulting from Middle to Late Jurassic and Eocene to Oligocene plutonism and cospatial dyking. Upper Triassic-Lower Jurassic and most Cretaceous strata are overmature on Moresby Island, with R{sub 0} values ranging from 2.40 to 5.80%. Jurassic, Cretaceous, and Tertiary strata are immature to overmature on Graham Island, with R{sub 0} values ranging from 0.15% (Skonun Formation) to 2.4% (Haida Formation). Locally, R{sub 0} values up to 3.2% on Graham Island and 8.3% on Moresby Island occur adjacent to igneous intrusives. Modeling measured levels of organic maturation suggests that elevated geothermal gradients ranging from 83{degree} to 150{degree}C/km existed during Yakoun (183-178 Ma) and Masset (35-10 Ma) volcanism on Graham Island. Numerical modeling further suggests that Triassic strata on Fredrick Island and Kennecott Point (Graham Island) entered the oil window during the early Miocene, whereas Jurassic strata at Rennell Junction and Cumshewa Inlet entered the oil window during the Bajocian. Cretaceous strata on north and south Graham Island entered the oil window during the early Miocene and are currently within the oil window. The Tertiary Skonun Formation is generally immature except for strata on west and northeast Graham Island, which entered the oil window in the late Miocene.

  3. Wintering Reserve Queens in Mini-Plus and 3-Comb Nuclei

    Directory of Open Access Journals (Sweden)

    Siuda Maciej

    2014-06-01

    Full Text Available The aim of this study was to develop an effective method of overwintering reserve honey bee queens in two-storey mini-plus mating nuclei and in 3-comb nuclei (frames 36 x 26 cm, Wielkopolski hive. The assay was performed during three wintering seasons (2005 - 2008 parallel at two centers in Poland: the Division of Apiculture at the University of Life Sciences (SGGW in Warsaw, and the Apiculture Division at the University of Warmia and Mazury (UWM in Olsztyn. The results showed that 59% of queens overwintered in mini-plus nuclei and 77% in 3-comb nuclei. Among queens in mini-plus nuclei 63% overwintered in bee yard and only 55% in cellar. Within queens in 3-comb nuclei, 62% overwintered in Olsztyn and 91% in Warsaw. The highest survival rate of 93% was observed in Warsaw during the first season. Due to low survival rate, it is not recommended to overwinter the queens in miniplus nuclei.

  4. Red Queen Processes Drive Positive Selection on Major Histocompatibility Complex (MHC Genes.

    Directory of Open Access Journals (Sweden)

    Maciej Jan Ejsmond

    2015-11-01

    Full Text Available Major Histocompatibility Complex (MHC genes code for proteins involved in the incitation of the adaptive immune response in vertebrates, which is achieved through binding oligopeptides (antigens of pathogenic origin. Across vertebrate species, substitutions of amino acids at sites responsible for the specificity of antigen binding (ABS are positively selected. This is attributed to pathogen-driven balancing selection, which is also thought to maintain the high polymorphism of MHC genes, and to cause the sharing of allelic lineages between species. However, the nature of this selection remains controversial. We used individual-based computer simulations to investigate the roles of two phenomena capable of maintaining MHC polymorphism: heterozygote advantage and host-pathogen arms race (Red Queen process. Our simulations revealed that levels of MHC polymorphism were high and driven mostly by the Red Queen process at a high pathogen mutation rate, but were low and driven mostly by heterozygote advantage when the pathogen mutation rate was low. We found that novel mutations at ABSs are strongly favored by the Red Queen process, but not by heterozygote advantage, regardless of the pathogen mutation rate. However, while the strong advantage of novel alleles increased the allele turnover rate, under a high pathogen mutation rate, allelic lineages persisted for a comparable length of time under Red Queen and under heterozygote advantage. Thus, when pathogens evolve quickly, the Red Queen is capable of explaining both positive selection and long coalescence times, but the tension between the novel allele advantage and persistence of alleles deserves further investigation.

  5. Winged queens replaced by reproductives smaller than workers in Mystrium ants

    Science.gov (United States)

    Molet, Mathieu; Peeters, Christian; Fisher, Brian L.

    2007-04-01

    In ants, winged queens that are specialized for independent colony foundation can be replaced by wingless reproductives better adapted for colony fission. We studied this shift in reproductive strategy by comparing two Mystrium species from Madagascar using morphometry, allometry and dissections. Mystrium rogeri has a single dealate queen in each colony with a larger thorax than workers and similar mandibles that allow these queens to hunt during non-claustral foundation. In contrast, Mystrium ‘red’ lacks winged queens and half of the female adults belong to a wingless ‘intermorph’ caste smaller and allometrically distinct from the workers. Intermorphs have functional ovaries and spermatheca while those of workers are degenerate. Intermorphs care for brood and a few mate and reproduce making them an all-purpose caste that takes charge of both work and reproduction. However, their mandibles are reduced and inappropriate for hunting centipedes, unlike the workers’ mandibles. This together with their small thorax disallow them to perform independent colony foundation, and colonies reproduce by fission. M. rogeri workers have mandibles polymorphic in size and shape, which allow for all tasks from brood care to hunting. In M. ‘red’, colonial investment in reproduction has shifted from producing expensive winged queens to more numerous helpers. M. ‘red’ intermorphs are the first case of reproductives smaller than workers in ants and illustrate their potential to diversify their caste system for better colonial economy.

  6. Cell motility, morphology, viability and proliferation in response to nanotopography on silicon black

    DEFF Research Database (Denmark)

    Lopacinska, Joanna M.; Gradinaru, Cristian; Wierzbicki, Rafal;

    2012-01-01

    viability and proliferation show little dependence on substrate type. We conclude that motility analysis can show a wide range of cell responses e. g. over a factor of two in cell speed to different nano-topographies, where standard assays, such as viability or proliferation, in the tested cases show much...... standard measurements of cell viability, proliferation, and morphology on various surfaces. We also analyzed the motility of cells on the same surfaces, as recorded in time lapse movies of sparsely populated cell cultures. We find that motility and morphology vary strongly with nano-patterns, while...

  7. Anti inflammatory and anti angiogenic effect of black raspberry extract on human esophageal and intestinal microvascular endothelial cells.

    Science.gov (United States)

    Medda, Rituparna; Lyros, Orestis; Schmidt, Jamie L; Jovanovic, Nebojsa; Nie, Linghui; Link, Benjamin J; Otterson, Mary F; Stoner, Gary D; Shaker, Reza; Rafiee, Parvaneh

    2015-01-01

    Polyphenolic compounds (anthocyanins, flavonoid glycosides) in berries prevent the initiation, promotion, and progression of carcinogenesis in rat's digestive tract and esophagus, in part, via anti-inflammatory pathways. Angiogenesis has been implicated in the pathogenesis of chronic inflammation and tumorigenesis. In this study, we investigated the anti-inflammatory and anti-angiogenic effects of black raspberry extract (BRE) on two organ specific primary human intestinal microvascular endothelial cells, (HIMEC) and human esophageal microvascular endothelial cells (HEMEC), isolated from surgically resected human intestinal and donor discarded esophagus, respectively. HEMEC and HIMEC were stimulated with TNF-α/IL-1β with or without BRE. The anti-inflammatory effects of BRE were assessed based upon COX-2, ICAM-1 and VCAM-1 gene and protein expression, PGE2 production, NFκB p65 subunit nuclear translocation as well as endothelial cell-leukocyte adhesion. The anti-angiogenic effects of BRE were assessed on cell migration, proliferation and tube formation following VEGF stimulation as well as on activation of Akt, MAPK and JNK signaling pathways. BRE inhibited TNF-α/IL-1β-induced NFκB p65 nuclear translocation, PGE2 production, up-regulation of COX-2, ICAM-1 and VCAM-1 gene and protein expression and leukocyte binding in HEMEC but not in HIMEC. BRE attenuated VEGF-induced cell migration, proliferation and tube formation in both HEMEC and HIMEC. The anti-angiogenic effect of BRE is mediated by inhibition of Akt, MAPK and JNK phosphorylations. BRE exerted differential anti-inflammatory effects between HEMEC and HIMEC following TNF-α/IL-1β activation whereas demonstrated similar anti-angiogenic effects following VEGF stimulation in both cell lines. These findings may provide more insight into the anti-tumorigenic capacities of BRE in human disease and cancer.

  8. Tolerating an infection: an indirect benefit of co-founding queen associations in the ant Lasius niger

    Science.gov (United States)

    Pull, Christopher D.; Hughes, William O. H.; Brown, Mark J. F.

    2013-12-01

    Pathogens exert a strong selection pressure on organisms to evolve effective immune defences. In addition to individual immunity, social organisms can act cooperatively to produce collective defences. In many ant species, queens have the option to found a colony alone or in groups with other, often unrelated, conspecifics. These associations are transient, usually lasting only as long as each queen benefits from the presence of others. In fact, once the first workers emerge, queens fight to the death for dominance. One potential advantage of co-founding may be that queens benefit from collective disease defences, such as mutual grooming, that act against common soil pathogens. We test this hypothesis by exposing single and co-founding queens to a fungal parasite, in order to assess whether queens in co-founding associations have improved survival. Surprisingly, co-foundresses exposed to the entomopathogenic fungus Metarhizium did not engage in cooperative disease defences, and consequently, we find no direct benefit of multiple queens on survival. However, an indirect benefit was observed, with parasite-exposed queens producing more brood when they co-founded, than when they were alone. We suggest this is due to a trade-off between reproduction and immunity. Additionally, we report an extraordinary ability of the queens to tolerate an infection for long periods after parasite exposure. Our study suggests that there are no social immunity benefits for co-founding ant queens, but that in parasite-rich environments, the presence of additional queens may nevertheless improve the chances of colony founding success.

  9. Optimization of Acetylene Black Conductive Additive andPolyvinylidene Difluoride Composition for High Power RechargeableLithium-Ion Cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, G.; Zheng, H.; Battaglia, V.S.; Simens, A.S.; Minor, A.M.; Song, X.

    2007-07-01

    Fundamental electrochemical methods were applied to study the effect of the acetylene black (AB) and the polyvinylidene difluoride (PVDF) polymer binder on the performance of high-power designed rechargeable lithium ion cells. A systematic study of the AB/PVDF long-range electronic conductivity at different weight ratios is performed using four-probe direct current tests and the results reported. There is a wide range of AB/PVDF ratios that satisfy the long-range electronic conductivity requirement of the lithium-ion cathode electrode; however, a significant cell power performance improvement is observed at small AB/PVDF composition ratios that are far from the long-range conductivity optimum of 1 to 1.25. Electrochemical impedance spectroscopy (EIS) tests indicate that the interfacial impedance decreases significantly with increase in binder content. The hybrid power pulse characterization results agree with the EIS tests and also show improvement for cells with a high PVDF content. The AB to PVDF composition plays a significant role in the interfacial resistance. We believe the higher binder contents lead to a more cohesive conductive carbon particle network that results in better overall all local electronic conductivity on the active material surface and hence reduced charge transfer impedance.

  10. Black Holes

    Science.gov (United States)

    Luminet, Jean-Pierre

    1992-09-01

    Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.

  11. Localization of deformed wing virus infection in queen and drone Apis mellifera L.

    Science.gov (United States)

    Fievet, Julie; Tentcheva, Diana; Gauthier, Laurent; de Miranda, Joachim; Cousserans, François; Colin, Marc Edouard; Bergoin, Max

    2006-03-28

    The distribution of deformed wing virus infection within the honey bee reproductive castes (queens, drones) was investigated by in situ hybridization and immunohistology from paraffin embedded sections. Digoxygenin or CY5.5 fluorochrome end-labelled nucleotide probes hybridizing to the 3' portion of the DWV genome were used to identify DWV RNA, while a monospecific antibody to the DWV-VP1 structural protein was used to identify viral proteins and particles. The histological data were confirmed by quantitative RT-PCR of dissected organs. Results showed that DWV infection is not restricted to the digestive tract of the bee but spread in the whole body, including queen ovaries, queen fat body and drone seminal vesicles.

  12. Behavioural development, fat reserves and their association with productivity in Lasius flavus founding queens

    Science.gov (United States)

    Norman, V. C.; Pamminger, T.; Hughes, W. O. H.

    2016-04-01

    Reproduction-related behaviours are key components determining individual fitness. Many behavioural traits are linked, and such trait associations often affect fitness. Here, we combine behavioural and physiological data during two critical time points of founding queens (early and late nest-founding stage) in the claustral ant Lasius flavus to assess how these factors affect their initial productivity. We show that most behavioural traits, except brood care behaviour, are plastic during queen development and demonstrate that there are alternative behavioural pathways to achieve high productivity under standardised conditions. These results indicate that queens can utilise multiple behavioural trait combinations to maximise reproductive output at the earliest, and arguably most critical, time of colony foundation.

  13. When can ants discriminate the sex of brood? A new aspect of queen-worker conflict.

    Science.gov (United States)

    Nonacs, P; Carlin, N F

    1990-12-15

    The stage in preimaginal ontogeny at which the sexes can first be distinguished has important implications for queen-worker conflict in social insects. If workers are unable to sex larvae at an early instar, their opportunity to control colony reproductive strategies may be limited. In addition, by concealing the sex of her sons for some portion of development, the queen could protect them from the workers' attempts to substitute their own sons or to skew the numerical sex ratio. In a series of choice experiments, workers of the carpenter ant, Camponotus floridanus, failed to discriminate the sex of several stages of larvae but did retrieve female pupae significantly more rapidly than male pupae. Our results suggest that in this species, sex may not become detectable until pupation, which is consistent with sexual deception as an aspect of queen control.

  14. Localization of deformed wing virus infection in queen and drone Apis mellifera L

    Directory of Open Access Journals (Sweden)

    Colin Marc

    2006-03-01

    Full Text Available Abstract The distribution of deformed wing virus infection within the honey bee reproductive castes (queens, drones was investigated by in situ hybridization and immunohistology from paraffin embedded sections. Digoxygenin or CY5.5 fluorochrome end-labelled nucleotide probes hybridizing to the 3' portion of the DWV genome were used to identify DWV RNA, while a monospecific antibody to the DWV-VP1 structural protein was used to identify viral proteins and particles. The histological data were confirmed by quantitative RT-PCR of dissected organs. Results showed that DWV infection is not restricted to the digestive tract of the bee but spread in the whole body, including queen ovaries, queen fat body and drone seminal vesicles.

  15. Composite films of carbon black nanoparticles and sulfonated-polythiophene as flexible counter electrodes for dye-sensitized solar cells

    Science.gov (United States)

    Li, Chun-Ting; Lee, Chi-Ta; Li, Sie-Rong; Lee, Chuan-Pei; Chiu, I.-Ting; Vittal, R.; Wu, Nae-Lih; Sun, Shih-Sheng; Ho, Kuo-Chuan

    2016-01-01

    A composite film based on carbon black nanoparticles and sulfonated-poly(thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-diyl) (CB-NPs/s-PT) is formed on a flexible titanium foil for the use as the electro-catalytic counter electrode (CE) of dye-sensitized solar cells (DSSCs). The CB-NPs provide the large amount of electro-catalytic active sites for the composite film, and the s-PT polymer serves as a conductive binder to enhance the inter-particle linkage among CB-NPs and to improve the adhesion between the composite film and the flexible substrate. The flexible CB-NPs/s-PT composite film is designed to possess good electro-catalytic ability for I-/I3- redox couple by providing large active sites and rapid reduction kinetic rate constant of I3- . The cell with a CB-NPs/s-PT CE exhibits a good cell efficiency (η) of 9.02 ± 0.01% at 100 mW cm-2, while the cell with a platinum CE shows an η of only 8.36 ± 0.02% under the same conditions. At weak light illuminations (20-80 mW cm-2), a DSSC with CB-NPs/s-PT CE still exhibits η's of 7.20 ± 0.04-9.08 ± 0.02%. The low-cost CB-NPs/s-PT CE not only renders high cell efficiency to its DSSC but also shows a great potential to replace the expensive platinum; moreover it is suitable for large-scale production or for indoor applications.

  16. Improving the Spectral Response of Black Dye by Cosensitization with a Simple Indoline Based Dye in Dye-Sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    Md. Akhtaruzzaman

    2013-01-01

    Full Text Available Indoline dye D-1 was successfully applied as a cosensitizer for improving the spectral response of black dye in dye-sensitized solar cells (DSCs. It was observed that D-1 effectively increases the short-circuit photocurrent by offsetting the competitive light absorption by I/I3- electrolyte in the wavelength region 350–500 nm when adsorbed on the TiO2 nanocrystaline films in a mix dye system. The DSCs containing the D-1 and black dye achieved a power conversion efficiency of 9.80% with higher short-circuit photocurrent of 19.54 mA/cm2 compared to the system of black dye without cosensitization under standard AM 1.5 sunlight.

  17. Black Raspberry Extract Increased Circulating Endothelial Progenitor Cells and Improved Arterial Stiffness in Patients with Metabolic Syndrome: A Randomized Controlled Trial.

    Science.gov (United States)

    Jeong, Han Saem; Kim, Sohyeon; Hong, Soon Jun; Choi, Seung Cheol; Choi, Ji-Hyun; Kim, Jong-Ho; Park, Chi-Yeon; Cho, Jae Young; Lee, Tae-Bum; Kwon, Ji-Wung; Joo, Hyung Joon; Park, Jae Hyoung; Yu, Cheol Woong; Lim, Do-Sun

    2016-04-01

    Administration of black raspberry (Rubus occidentalis) is known to improve vascular endothelial function in patients at a high risk for cardiovascular (CV) disease. We investigated short-term effects of black raspberry on circulating endothelial progenitor cells (EPCs) and arterial stiffness in patients with metabolic syndrome. Patients with metabolic syndrome (n = 51) were prospectively randomized into the black raspberry group (n = 26, 750 mg/day) and placebo group (n = 25) during the 12-week follow-up. Central blood pressure, augmentation index, and EPCs, such as CD34/KDR(+), CD34/CD117(+), and CD34/CD133(+), were measured at baseline and at 12-week follow-up. Radial augmentation indexes were significantly decreased in the black raspberry group compared to the placebo group (-5% ± 10% vs. 3% ± 14%, P raspberry group compared to the placebo group (19 ± 109/μL vs. -28 ± 57/μL, P raspberry group compared to the placebo group (-0.5 ± 1.4 pg/mL vs. -0.1 ± 1.1 pg/mL, P raspberry group. The use of black raspberry significantly lowered the augmentation index and increased circulating EPCs, thereby improving CV risks in patients with metabolic syndrome during the 12-week follow-up.

  18. Samuel Alexander Kinnier Wilson. Wilson's disease, Queen Square and neurology.

    Science.gov (United States)

    Broussolle, E; Trocello, J-M; Woimant, F; Lachaux, A; Quinn, N

    2013-12-01

    This historical article describes the life and work of the British physician Samuel Alexander Kinnier Wilson (1878-1937), who was one of the world's greatest neurologists of the first half of the 20th century. Early in his career, Wilson spent one year in Paris in 1903 where he learned from Pierre-Marie at Bicêtre Hospital. He subsequently retained uninterrupted links with French neurology. He also visited in Leipzig the German anatomist Paul Flechsig. In 1904, Wilson returned to London, where he worked for the rest of his life at the National Hospital for the Paralysed and Epileptic (later the National Hospital for Nervous Diseases, and today the National Hospital for Neurology and Neurosurgery) in Queen Square, and also at Kings' College Hospital. He wrote on 'the old motor system and the new', on disorders of motility and muscle tone, on the epilepsies, on aphasia, apraxia, tics, and pathologic laughing and crying, and most importantly on Wilson's disease. The other objective of our paper is to commemorate the centenary of Wilson's most important work published in 1912 in Brain, and also in Revue Neurologique, on an illness newly recognized and characterized by him entitled "Progressive lenticular degeneration, a familial nervous disease associated with liver cirrhosis". He analyzed 12 clinical cases, four of whom he followed himself, but also four cases previously published by others and a further two that he considered in retrospect had the same disease as he was describing. The pathological profile combined necrotic damage in the lenticular nuclei of the brain and hepatic cirrhosis. This major original work is summarized and discussed in the present paper. Wilson not only delineated what was later called hepato-lenticular degeneration and Wilson's disease, but also introduced for the first time the terms extrapyramidal syndrome and extrapyramidal system, stressing the role of the basal ganglia in motility. The present historical work emphasizes the special

  19. 76 FR 82413 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Science.gov (United States)

    2011-12-30

    ... Part 622 Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants... Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and... the FMP for the Spiny Lobster Fishery of Puerto Rico and the U.S. Virgin Islands (Spiny Lobster...

  20. 76 FR 59377 - Amendments to the Reef Fish, Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and...

    Science.gov (United States)

    2011-09-26

    ..., Spiny Lobster, Queen Conch and Coral and Reef Associated Plants and Invertebrates Fishery Management... Fishery Management Plans (FMPs) for Reef Fish Resources, Spiny Lobster, Queen Conch, and Coral and Reef... (AMs) if ACLs should be exceeded for selected reef fish, spiny lobster, and aquarium trade...

  1. Behavioral Differentiation and Ovarian Development of Unmated Gynes, Queens, and Workers of Ectatomma vizottoi Almeida 1987 (Formicidae, Ectatomminae

    Directory of Open Access Journals (Sweden)

    Alexsandro Santana Vieira

    2012-01-01

    Full Text Available Behavioral differentiation and ovarian development of unmated gynes, queens, and workers of Ectatomma vizottoi were investigated in laboratory conditions. Forty-one behavioral acts were identified and quantified for workers, 19 for queens and 24 for unmated gynes, for an overall species repertoire of 42 different behavioral acts. Ovipositing reproductive eggs was an exclusive task of the queen, whereas workers showed 15 caste-specific behaviors. The most important (frequent behaviors for the queens were brood care, immobility, and reproduction, and for workers were immobility, grooming/interaction, brood care, and foraging. Unmated gynes (not winged primarily showed immobility, brood care, grooming/interaction, and foraging. Analysis of ovarian development showed that unmated gynes had little-developed ovarioles, in contrast to queens. Queens and unmated gynes showed a clear behavioral differentiation, in which queens played the role of reproducers and unmated gynes performed activities belonging to the worker repertoire. Despite the presence of several breeding queens in the colony, functional monogyny was the rule.

  2. 77 FR 51763 - Endangered and Threatened Wildlife; 90-Day Finding on a Petition To List the Queen Conch as...

    Science.gov (United States)

    2012-08-27

    ... scale poaching by foreigners (CITES, 2003, 2005). The review also found that intensive fishing pressure.... The petition cites several peer-reviewed publications and research studies that show queen conch in... only to the status of the queen conch throughout its range. Peer Review On July 1, 1994, NMFS,...

  3. Growth and survival of juvenile queen conch, Strombus gigas fed artificial diets containing varying levels of digestible protein and energy

    Science.gov (United States)

    Aquaculture methods for queen conch, Strombus gigas, have been established for several decades. However, there is a need to improve husbandry techniques for the growout of juveniles. The purpose of this study was to determine growth and survival of juvenile queen conch fed artificial diets with incr...

  4. Black silicon laser-doped selective emitter solar cell with 18.1% efficiency

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Li, Hongzhao; To, Alexander;

    2016-01-01

    We report fabrication of nanostructured, laser-doped selective emitter (LDSE) silicon solar cells with power conversion efficiency of 18.1% and a fill factor (FF) of 80.1%. The nanostructured solar cells were realized through a single step, mask-less, scalable reactive ion etch (RIE) texturing...... efficiency indicates a promising potential, especially considering that the cell reported in this work is the first proof-of-concept and that the fabricated cell is not fully optimized in terms of plating, emitter sheet resistance and surface passivation. Due to the scalable nature and simplicity of RIE......-texturing as well as the LDSE process, we consider this specific combination a promising candidate for a cost-efficient process for future Si solar cells....

  5. Differences in expression of gut-homing receptors on CD4+ T cells in black and white HIV-negative men who have sex with men.

    Science.gov (United States)

    Kelley, Colleen F; Lai, Lilin; Ibegbu, Chris; Rosenberg, Eli S; Kaur, Surinder; Patel, Kalpana; Mulligan, Mark J; Marconi, Vincent C; Sullivan, Patrick S; Amara, Rama R

    2016-05-15

    HIV incidence rates are higher among black men who have sex with men (BMSM) as compared with MSM of other race/ethnicities in the USA. We found that blood memory CD4 cells from BMSM express higher levels of α4β7, the gut-homing integrin, compared with white MSM. Higher expression of α4β7 on blood CD4 cells correlated with higher percentage of proliferating CD4α4β7 cells in rectal tissue suggesting increased trafficking of potential HIV target cells to rectal mucosa could increase HIV susceptibility among BMSM.

  6. Counting solutions for the N -queens and Latin-square problems by Monte Carlo simulations.

    Science.gov (United States)

    Zhang, Cheng; Ma, Jianpeng

    2009-01-01

    We apply Monte Carlo simulations to count the numbers of solutions of two well-known combinatorial problems: the N -queens problem and Latin-square problem. The original system is first converted to a general thermodynamic system, from which the number of solutions of the original system is obtained by using the method of computing the partition function. Collective moves are used to further accelerate sampling: swap moves are used in the N -queens problem and a cluster algorithm is developed for the Latin squares. The method can handle systems of 10;{4}degrees of freedom with more than 10;{10,000} solutions.

  7. Mosaic male honey bees produced by queens inseminated with frozen spermatozoa.

    Science.gov (United States)

    Harbo, J R

    1980-01-01

    Mosaic male honey bees were found as the progeny of queens that had been inseminated with spermatozoa stored in liquid nitrogen. The origins of these mosaics and the genotype of their gametes were determined by using mutant markers. The mosaics probably developed from an egg pronucleus and a sperm pronucleus that did not unite after the latter had entered the egg. Instead, both pronuclei produced haploid tissue independently. The three mosaics that were mated to queens all had mosaic testes. Therefore, these were situations in which a male honey bee produced two types of spermatozoa.

  8. Colony fusion and worker reproduction after queen loss in army ants

    DEFF Research Database (Denmark)

    Kronauer, Daniel J C; Schöning, Caspar; d'Ettorre, Patrizia

    2010-01-01

    Theory predicts that altruism is only evolutionarily stable if it is preferentially directed towards relatives, so that any such behaviour towards seemingly unrelated individuals requires scrutiny. Queenless army ant colonies, which have anecdotally been reported to fuse with queenright foreign c...... loss might be more widespread, especially in spatially structured populations of social insects where worker reproduction is not profitable....... their reproductive success. We show that worker chemical recognition profiles remain similar after queen loss, but rapidly change into a mixed colony Gestalt odour after fusion, consistent with indiscriminate acceptance of alien workers that are no longer aggressive. We hypothesize that colony fusion after queen...

  9. Chemical communication in Ropalidia marginata: Dufour's gland contains queen signal that is perceived across colonies and does not contain colony signal.

    Science.gov (United States)

    Mitra, Aniruddha; Saha, Paromita; Chaoulideer, Maximilian Elihu; Bhadra, Anindita; Gadagkar, Raghavendra

    2011-02-01

    Queens of the primitively eusocial wasp Ropalidia marginata appear to maintain reproductive monopoly through pheromone rather than through physical aggression. Upon queen removal, one of the workers (potential queen, PQ) becomes extremely aggressive but drops her aggression immediately upon returning the queen. If the queen is not returned, the PQ gradually drops her aggression and becomes the next queen of the colony. In a previous study, the Dufour's gland was found to be at least one source of the queen pheromone. Queen-worker classification could be done with 100% accuracy in a discriminant analysis, using the compositions of their respective Dufour's glands. In a bioassay, the PQ dropped her aggression in response to the queen's Dufour's gland macerate, suggesting that the queen's Dufour's gland contents mimicked the queen herself. In the present study, we found that the PQ also dropped her aggression in response to the macerate of a foreign queen's Dufour's gland. This suggests that the queen signal is perceived across colonies. This also suggests that the Dufour's gland in R. marginata does not contain information about nestmateship, because queens are attacked when introduced into foreign colonies, and hence PQ is not expected to reduce her aggression in response to a foreign queen's signal. The latter conclusion is especially significant because the Dufour's gland chemicals are adequate to classify individuals correctly not only on the basis of fertility status (queen versus worker) but also according to their colony membership, using discriminant analysis. This leads to the additional conclusion (and precaution) that the ability to statistically discriminate organisms using their chemical profiles does not necessarily imply that the organisms themselves can make such discrimination.

  10. Sex allocation in fungus-growing ants: worker or queen control without symbiont-induced female bias

    DEFF Research Database (Denmark)

    Dijkstra, Michiel B.; Boomsma, Jacobus Jan

    2008-01-01

    with the theoretical queen and worker optima for a range of values of k, the correction factor for sex differences in metabolic rate and fat content. The results were consistent with either worker or queen control, but never with fungal control for any realistic value of k. We conclude that the fungal symbiont does......The fungal cultivars of fungus-growing ants are vertically transmitted by queens but not males. Selection would therefore favor cultivars that bias the ants' sex ratio towards gynes, beyond the gyne bias that is optimal for workers and queens. We measured sex allocation in 190 colonies of six...... sympatric fungus-growing ant species. As predicted from relatedness, female bias was greater in four singly mated Sericomyrmex and Trachymyrmex species than in two multiply mated Acromyrmex species. Colonies tended to raise mainly a single sex, which could be partly explained by variation in queen number...

  11. INFLUENCE OF HONEYBEE QUEENS ORIGIN TO THE PRODUCTION CHARACTERISTICS OF CARNIOLAN BEES (APIS MELLIFERA CARNICA IN SLOVENIA

    Directory of Open Access Journals (Sweden)

    J POKLUKAR

    2002-05-01

    Full Text Available Total amount of 4.355 records of honeybee colonies production characteristics was estimated on the 251 bee yards in Slovenia from 1993 to 2001. Queens were produced on 29 queen producing yards. The average lsmeans of honey yields increased by 0,41 kg a year. The swarming behaviour and the defensive behaviour of bees increased as well by - 0,091 points, and –0,038 points respectively. According to the last two years records, the honey yields of bee colonies were significantly influenced by the drone gene pool at queen production yards. The swarming behaviour was in contrary more influenced by the queen mothers on queen production yards. The defensive behaviour of bee colonies and the daily varroa mite fall were not significantly influenced by parents.

  12. Larval and nurse worker control of developmental plasticity and the evolution of honey bee queen-worker dimorphism.

    Science.gov (United States)

    Linksvayer, T A; Kaftanoglu, O; Akyol, E; Blatch, S; Amdam, G V; Page, R E

    2011-09-01

    Social evolution in honey bees has produced strong queen-worker dimorphism for plastic traits that depend on larval nutrition. The honey bee developmental programme includes both larval components that determine plastic growth responses to larval nutrition and nurse components that regulate larval nutrition. We studied how these two components contribute to variation in worker and queen body size and ovary size for two pairs of honey bee lineages that show similar differences in worker body-ovary size allometry but have diverged over different evolutionary timescales. Our results indicate that the lineages have diverged for both nurse and larval developmental components, that rapid changes in worker body-ovary size allometry may disrupt queen development and that queen-worker dimorphism arises mainly from discrete nurse-provided nutritional environments, not from a developmental switch that converts variable nutritional environments into discrete phenotypes. Both larval and nurse components have likely contributed to the evolution of queen-worker dimorphism.

  13. Evaluation of Platinum-Black Stimulus Electrode Array for Electrical Stimulation of Retinal Cells in Retinal Prosthesis System

    Science.gov (United States)

    Watanabe, Taiichiro; Kobayashi, Risato; Komiya, Ken; Fukushima, Takafumi; Tomita, Hiroshi; Sugano, Eriko; Kurino, Hiroyuki; Tanaka, Tetsu; Tamai, Makoto; Koyanagi, Mitsumasa

    2007-04-01

    A retinal prosthesis system with a three-dimensionally (3D) stacked LSI chip has been proposed. We fabricated a new implantable stimulus electrode array deposited with Platinum-black (Pt-b) on a polyimide-based flexible printed circuit (FPC) for the electrical stimulation of the retinal cells. Impedance measurement of the Pt-b electrode-electrolyte interface in a saline solution was performed and the Pt-b electrode realized a very low impedance. The power consumption at the electrode array when retinal cells were stimulated by a stimulus current was evaluated. The power consumption of the Pt-b stimulus electrode array was 91% lower than that of a previously fabricated Al stimulus electrode array due to a convexo-concave surface. In the cytotoxicity test (CT), we confirmed that Pt implantation induced no cellular degeneration of the rat retina. In the animal experiments, electrically evoked potential (EEP) was successfully recorded using Japanese white rabbits. These results indicate that electrical stimulation using the Pt-b stimulus electrode array can restore visual sensation.

  14. Ethanolic extract of Actaea racemosa (black cohosh) potentiates bone nodule formation in MC3T3-E1 preosteoblast cells.

    Science.gov (United States)

    Chan, B Y; Lau, K S; Jiang, B; Kennelly, E J; Kronenberg, F; Kung, A W C

    2008-09-01

    Aceaea racemosa (formerly Cimicifuga racemosa, black cohosh, AR) extracts have been widely used as an alternative to hormonal replacement therapy for menopausal symptoms. Recent evidences suggest AR extracts are also effective in protecting against postmenopausal bone loss. To determine whether AR has any direct anabolic effect on osteoblasts, we investigated the ethanolic extract of AR on bone nodule formation in mouse MC3T3-E1 preosteoblast cells. AR did not stimulate osteoblast proliferation. Rather, at high doses of 1000 ng/mL for 48 h, AR suppressed (7.2+/-0.9% vs. control) osteoblast proliferation. At 500 ng/mL, a significant increase in bone nodule formation was seen with Von Kossa staining. Using quantitative PCR analysis, AR was shown to enhance the gene expression of runx2 and osteocalcin. Co-treatment with ICI 182,780, the selective estrogen receptor antagonist, abolished the stimulatory effect of AR on runx2 and osteocalcin gene induction, as well as on bone nodule formation in MC3T3-E1 cells. This is a first report of the direct effect of AR on enhancement of bone nodule formation in osteoblasts, and this action was mediated via an estrogen receptor-dependent mechanism. The results provide a scientific rationale at the molecular level for the claim that AR can offer effective prevention of postmenopausal bone loss.

  15. National Assessment of Oil and Gas Project - Black Warrior Province (065) Quarter-Mile Cells

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Cell maps for each oil and gas assessment unit were created by the USGS as a method for illustrating the degree of exploration, type of production, and distribution...

  16. Rice Brittleness Mutants: A Way to Open the 'Black Box' of Monocot Cell Wall Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Baocai Zhang; Yihua Zhou

    2011-01-01

    Rice is a model organism for studying the mechanism of cell wall biosynthesis and remolding in Gramineae.Mechanical strength is an important agronomy trait of rice(Oryza sativa L.)plants that affects crop lodging and grain yield.As a prominent physical property of cell walls,mechanical strength reflects upon the structure of different wall polymers and how they interact.Studies on the mechanisms that regulate the mechanical strength therefore consequently results in uncovering the genes functioning in cell wall biosynthesis and remodeling.Our group focuses on the study of isolation of brittle culm(bc)mutants and characterization of their corresponding genes.To date,several bc mutants have been reported.The identified genes have covered several pathways of cell wall biosynthesis,revealing many secrets of monocot cell wall biosynthesis.Here,we review the progress achieved in this research field and also highlight the perspectives in expectancy.All of those lend new insights into mechanisms of cell wall formation and are helpful for harnessing the waste rice straws for biofuel production.

  17. Protein content of leaf-cutting ant queens before the nuptial flight and during the post-claustral phase

    Directory of Open Access Journals (Sweden)

    Edypo Jacob Silva

    2014-12-01

    Full Text Available Protein content of leaf-cutting ant queens before the nuptial flight and during the post-claustral phase. This study evaluated the crude protein content of queens of Atta sexdens before the nuptial flight and after the claustral phase in laboratory and field colonies. The hypothesis was that protein is used for survival of the queen and for early colony growth during the claustral phase. Additionally, the nest morphology, live biomass and adult population of field colonies were evaluated. Crude protein was determined by digestion of the organic material with sulfuric acid at high temperatures. The mean crude protein content was 123.23 ± 11.20 mg for females before the nuptial flight and 70.44 ± 12.21 mg for laboratory-reared queens after the claustral phase. The post-claustral crude protein content of field-collected queen was 55.90 ± 9.18 mg. With respect to the loss of crude protein as a function of duration of the claustral phase, laboratory-reared queens lost 52.79 mg and field-collected queens lost 67.33 mg compared to females before the nuptial flight. A positive linear correlation was observed between the weight of field-collected queens (256.4 ± 36.3 mg and colony biomass (13.02 ± 9.12 g, but there was no correlation between biomass and nest depth (13.11 ± 3.82 cm. As expected, the present results support the hypothesis that protein is used for survival of the queen and for early colony growth, as demonstrated by the reduction in crude protein content as a function of duration of the claustral phase. To our knowledge, this is the first study to provide data of the dynamics of protein reserves in leaf-cutting ant queens during the claustral phase.

  18. Black Culture

    Directory of Open Access Journals (Sweden)

    Angela Khristin Brown

    2013-07-01

    Full Text Available The migration of blacks in North America through slavery became united.  The population of blacks past downs a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape from poverty of enslavement and to establish a way of life through tradition. A way of personal freedoms was through getting a good education that lead to a better foundation and a better way of life.

  19. Piperine, a component of black pepper, decreases eugenol-induced cAMP and calcium levels in non-chemosensory 3T3-L1 cells.

    Science.gov (United States)

    Yoon, Yeo Cho; Kim, Sung-Hee; Kim, Min Jung; Yang, Hye Jeong; Rhyu, Mee-Ra; Park, Jae-Ho

    2015-01-01

    This study investigated the effects of an ethanol extract of black pepper and its constituent, piperine, on odorant-induced signal transduction in non-chemosensory cells. An ethanol extract of black pepper decreased eugenol-induced cAMP and calcium levels in preadipocyte 3T3-L1 cells with no toxicity. Phosphorylation of CREB (cAMP response element-binding protein) was down-regulated by the black pepper extract. The concentration (133.8 mg/g) and retention time (5.5 min) of piperine in the ethanol extract were quantified using UPLC-MS/MS. Pretreatment with piperine decreased eugenol-induced cAMP and calcium levels in 3T3-L1 cells. Piperine also decreased the phosphorylation of CREB, which is up-regulated by eugenol. These results suggest that piperine inhibits the eugenol-induced signal transduction pathway through modulation of cAMP and calcium levels and phosphorylation of CREB in non-chemosensory cells.

  20. Red Queen Takes White Knight: The Commercialisation of Accounting Education in Australia

    Directory of Open Access Journals (Sweden)

    Graham Bowrey

    2015-09-01

    Full Text Available This paper investigates the adaptive and maladaptive consequences of changes resulting from the commercialisation of Australian universities, specifically their accounting schools, and aims to identify the organisational changes triggered by competition that affect the growth of universities over time. The paper synthesises organisational learning theory, benchmarking theory, mimetic isomorphism and institutional theories, which are presented as "the Red Queen", itself an evolutionary theory; this synthesis provides the theoretical underpinning. The Red Queen theory posits that competition triggers organisational learning, which in turn intensifies competition in rivals that ultimately triggers an adaptive response. This selfreinforcing process produces results that may be adaptive or maladaptive. There is evidence to support that “running fast” in terms of Red Queen evolution theory has allowed some universities to place competitive pressure on rivals and achieve elite levels of publications, international accreditation and improved international rankings. This search for improvement, driven by commercialisation, provided ways to improve performance, thus improving the university’s competitive strength. There is also evidence to support the belief that “running slow” provides maladaptive consequences that could affect growth rates, quality and staff performance. The use of the Red Queen hypothesis provides an evolutionary approach to the study of strategy, strategic change and organisations. This provides an opportunity to examine competition in universities as a force that continually disturbs equilibrium.

  1. Asymmetric ecological conditions favor Red-Queen type of continued evolution over stasis.

    Science.gov (United States)

    Nordbotten, Jan Martin; Stenseth, Nils C

    2016-02-16

    Four decades ago, Leigh Van Valen presented the Red Queen's hypothesis to account for evolution of species within a multispecies ecological community [Van Valen L (1973) Evol Theory 1(1):1-30]. The overall conclusion of Van Valen's analysis was that evolution would continue even in the absence of abiotic perturbations. Stenseth and Maynard Smith presented in 1984 [Stenseth NC, Maynard Smith J (1984) Evolution 38(4):870-880] a model for the Red Queen's hypothesis showing that both Red-Queen type of continuous evolution and stasis could result from a model with biotically driven evolution. However, although that contribution demonstrated that both evolutionary outcomes were possible, it did not identify which ecological conditions would lead to each of these evolutionary outcomes. Here, we provide, using a simple, yet general population-biologically founded eco-evolutionary model, such analytically derived conditions: Stasis will predominantly emerge whenever the ecological system contains only symmetric ecological interactions, whereas both Red-Queen and stasis type of evolution may result if the ecological interactions are asymmetrical, and more likely so with increasing degree of asymmetry in the ecological system (i.e., the more trophic interactions, host-pathogen interactions, and the like there are [i.e., +/- type of ecological interactions as well as asymmetric competitive (-/-) and mutualistic (+/+) ecological interactions]). In the special case of no between-generational genetic variance, our results also predict dynamics within these types of purely ecological systems.

  2. Social and genetic structure of a supercolonial weaver ant, Polyrhachis robsoni, with dimorphic queens

    DEFF Research Database (Denmark)

    Van Zweden, Jelle Stijn; Carew, Melissa E.; Henshaw, Michael T.;

    2007-01-01

    reduction of the former. Aggression tests showed that hostility between ants from different nests was minimal. Nests frequently contained numbers of both queen types, with microgynes about twice as numerous as macrogynes. Nestmate workers, microgynes, and macrogynes, were significantly related to others...

  3. A genetic component to size in queens of the ant, Formica truncorum

    DEFF Research Database (Denmark)

    Bargum, Katja; Boomsma, Jacobus Jan; Sundström, L.

    2004-01-01

    The genetic basis of morphological traits in social insects remains largely unexplored. This is even true for individual body size, a key life-history trait. In the social insects, the size of reproductive individuals affects dispersal decisions, so that small size in queens is often associated...

  4. GC-MS investigation of the chemical composition of honeybee drone and queen larvae homogenate

    Directory of Open Access Journals (Sweden)

    Isidorov Valery A.

    2016-06-01

    Full Text Available Honeybee larva homogenate appears to be underrated and insufficiently explored but this homogenate is an exceptionally valuable honeybee product. Drone larva homogenate is very nutritional due to its high content of proteins, free amino acids, lipids, and carbohydrates. Moreover, the biological characteristics of honeybee larvae indicate the presence of chemical substances that may be pharmacologically active. In spite of the above, the chemical composition of honeybee larva has not gained as much attention as that of other bee products. In this study, the chemical composition of honeybee brood homogenate has been investigated using gas chromatography/mass spectrometry. As a result, it was possible to isolate as many as 115 extractive organic compounds from 6 samples of crude queen and 9 samples of drone homogenate. The main groups of substances extracted from either type of homogenate were composed of free amino acids and carbohydrates. The relative content of amino acids in queen homogenate as well as the share of essential amino acids were found to be higher than in the drone homogenate. Disaccharide trehalose was the dominant sugar in the queen larvae, whilst glucose prevailed in the drone larvae. Comparative chemical analyses of honeybee queen and drone larva homogenates have allowed us to make a preliminary inference about a higher overall value of the former.

  5. Establishing Female Rule in Sixteenth Century England: A Tale of Two Queens

    Institute of Scientific and Technical Information of China (English)

    LinMeixiang; ZhuShida; DavidKelly

    2004-01-01

    When Mary I, the first queen of England (1553-1558) and Elizabeth I (1558-1603) were in power, they faced dual challenges: suspicion about the inheritance of the imperial power and general social anxiety about the rule of women. Mary I worked to make her rule legitimate by establishing a united rule through marriage.

  6. Evolution of the asexual queen succession system and its underlying mechanisms in termites.

    Science.gov (United States)

    Matsuura, Kenji

    2017-01-01

    One major advantage of sexual reproduction over asexual reproduction is its promotion of genetic variation, although it reduces the genetic contribution to offspring. Queens of social insects double their contribution to the gene pool, while overuse of asexual reproduction may reduce the ability of the colony to adapt to environmental stress because of the loss of genetic diversity. Recent studies have revealed that queens of some termite species can solve this tradeoff by using parthenogenesis to produce the next generation of queens and sexual reproduction to produce other colony members. This reproductive system, known as asexual queen succession (AQS), has been identified in the subterranean termites Reticulitermes speratus, Reticulitermes virginicus and Reticulitermes lucifugus and in the Neotropical higher termites Embiratermes neotenicus and Cavitermes tuberosus The studies presented here have uncovered the unusual modes of reproduction in termites and have aimed to identify their underlying mechanisms. The study of AQS, the mixed use of sexual and asexual reproduction, is of fundamental importance as it may provide a key to solve the evolutionary paradox of sex.

  7. Workers and alate queens of Solenopsis geminata share qualitatively similar but quantitatively different venom alkaloid chemistry

    Directory of Open Access Journals (Sweden)

    Qun-Hui eShi

    2015-07-01

    Full Text Available Solenopsis geminata group (Hymenoptera: Formicidae encompasses ant species commonly called fire ants because of their painful sting. The many physiological effects of the venom are caused by 2-methyl-6-alkyl and/or alkenylpiperidine alkaloids. The variation in piperidine alkaloid structures has useful taxonomic characters. The most well studied Solenopsis species is S. invicta, which was accidentally imported into the USA in the 1930s from South America. It quickly spread throughout the southern USA and is now a major invasive pest ant in the USA and in other parts of the world. Interestingly, the invasive S. invicta has largely displaced a native USA fire ant, S. geminata, from the southern USA. We explore the possibility that differences in venom chemistry could be correlated with this displacement. The cis and trans alkaloids from body extracts of workers and alate queens of S. geminata were separated by silica gel chromatography, identified, and quantitated by GC-MS analysis. Both workers and alate queens produce primarily cis- and trans-2-methyl-6-n-undecyl-piperidines, as well as other minor alkaloid components. Imported fire ant, S. invicta, alate queens produce the same alkaloids as S. geminata alate queens, but in contrast S. invicta workers produce piperidine alkaloids with longer side chains, which are purported to be physiologically more effective. These results are discussed in relation to the evolutionary progression of fire ant venom alkaloids and displacement of S. geminata by S. invicta in the USA.

  8. Identifying the Transition between Single and Multiple Mating of Queens in Fungus-Growing Ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Murakami, Takahiro; Schultz, Ted R.

    2002-01-01

    Obligate mating of females (queens) with multiple males has evolved only rarely in social Hymenoptera (ants, social bees, social wasps) and for reasons that are fundamentally different from those underlying multiple mating in other animals. The monophyletic tribe of ('attine') fungus-growing ants...

  9. Identifying the transition between single and multiple mating of queens in fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Murakami, Takahiro; Schultz, Ted R

    2002-01-01

    Obligate mating of females (queens) with multiple males has evolved only rarely in social Hymenoptera (ants, social bees, social wasps) and for reasons that are fundamentally different from those underlying multiple mating in other animals. The monophyletic tribe of ('attine') fungus-growing ants...

  10. Morphometric Identification of Queens, Workers and Intermediates in In Vitro Reared Honey Bees (Apis mellifera)

    Science.gov (United States)

    A. De Souza, Daiana; Wang, Ying; Kaftanoglu, Osman; De Jong, David; V. Amdam, Gro; S. Gonçalves, Lionel; M. Francoy, Tiago

    2015-01-01

    In vitro rearing is an important and useful tool for honey bee (Apis mellifera L.) studies. However, it often results in intercastes between queens and workers, which are normally are not seen in hive-reared bees, except when larvae older than three days are grafted for queen rearing. Morphological classification (queen versus worker or intercastes) of bees produced by this method can be subjective and generally depends on size differences. Here, we propose an alternative method for caste classification of female honey bees reared in vitro, based on weight at emergence, ovariole number, spermatheca size and size and shape, and features of the head, mandible and basitarsus. Morphological measurements were made with both traditional morphometric and geometric morphometrics techniques. The classifications were performed by principal component analysis, using naturally developed queens and workers as controls. First, the analysis included all the characters. Subsequently, a new analysis was made without the information about ovariole number and spermatheca size. Geometric morphometrics was less dependent on ovariole number and spermatheca information for caste and intercaste identification. This is useful, since acquiring information concerning these reproductive structures requires time-consuming dissection and they are not accessible when abdomens have been removed for molecular assays or in dried specimens. Additionally, geometric morphometrics divided intercastes into more discrete phenotype subsets. We conclude that morphometric geometrics are superior to traditional morphometrics techniques for identification and classification of honey bee castes and intermediates. PMID:25894528

  11. The Economic Impact of Queen's University Belfast on the Northern Ireland Economy. Higher Education in Focus

    Science.gov (United States)

    Kelly, Ursula; McNicoll, Iain; White, James

    2015-01-01

    This study provides an analysis of the economic impact of Queen's University Belfast and its students on the Northern Ireland economy. Based in the City of Belfast, the university has over 22,500 students. Its turnover of nearly £290 million makes it Northern Ireland's largest university in terms of its financial standing. With origins going back…

  12. Enhancement of Efficiency of a Solar Cell Fabricated on Black Si Made by Inductively Coupled Plasma-Reactive Ion Etching Process: A Case Study of a n-CdS/p-Si Heterojunction Cell.

    Science.gov (United States)

    Katiyar, Ajit K; Mukherjee, S; Zeeshan, M; Ray, Samit K; Raychaudhuri, A K

    2015-10-28

    We show that a significant enhancement of solar cell efficiency can be achieved in cells fabricated on black Si made using inductively coupled plasma-reactive ion etching (ICP-RIE). The ICP-RIE-fabricated black Si results in an array of vertically oriented defect-free Si nanocones (average height ∼150 nm; apex diameter ∼25 nm) exhibiting an average reflectance ≤2% over most of the relevant solar spectral range. The enabling role of the ultralow reflectance of the nanostructured black Si has been demonstrated using a heterojunction solar cell fabricated by depositing a n-type CdS film on p-Si nanocones followed by a transparent conducting coating of Al-doped ZnO (AZO). The fabricated n-CdS/p-Si heterojunction exhibits promising power conversion efficiency close to 3%, up from a mere efficient 0.15% for a similar cell fabricated on a planar Si. The effect of the fabrication process for the black Si on solar cell performance has been investigated through the measurements of carrier lifetime and surface recombination velocity. The accompanying model and simulation analysis shows that the conical structure leads to the effective dielectric constant varying smoothly from the value of the air at the top to the value of Si at the base over the length of the nanocone, leading to a substantial reduction of its reflectance.

  13. Load cycle durability of a graphitized carbon black-supported platinum catalyst in polymer electrolyte fuel cell cathodes

    Science.gov (United States)

    Takei, Chikara; Kakinuma, Katsuyoshi; Kawashima, Kazuhito; Tashiro, Keisuke; Watanabe, Masahiro; Uchida, Makoto

    2016-08-01

    We focus on Pt degradation occurring during fuel cell vehicle (FCV) combined drive cycles involving load and open circuit voltage (OCV) just after startup and during idling. Load cycle durability is evaluated as a function of OCV/load holding time, load rate and relative humidity (RH) with a graphitized carbon black-supported platinum catalyst (Pt/GCB) in the cathode. The degradation of Pt/GCB is suppressed for shorter OCV holding times, lower load rates and lower RH. Scanning ion microscopy (SIM) images of membrane cross-sections indicate that the amount of Pt deposited in the membrane decreases during drive cycles involving load with short OCV holding times. Investigations of the Pt distribution in the cathode catalyst layer (CL) by using scanning TEM-EDX show that the dissolution of Pt is suppressed on the membrane side in the CL. The Pt dissolution is accelerated by the high Pt oxidation due to the long OCV holding time. A load cycle with both long OCV holding time and low load inhibits the Pt2+ migration into the membrane but accelerates the Pt particle growth due to electrochemical Ostwald ripening; meanwhile, a load cycle with long OCV holding time at lower RH prevents both the Pt dissolution and particle growth.

  14. Improved Durability of Electrocatalyst Based on Coating of Carbon Black with Polybenzimidazole and their Application in Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Fujigaya, Tsuyohiko; Hirata, Shinsuke; Berber, Mohamed R; Nakashima, Naotoshi

    2016-06-15

    Improvement of durability of the electrocatalyst has been the key issue to be solved for the practical application of polymer electrolyte membrane fuel cells. One of the promising strategies to improve the durability is to enhance the oxidation stability of the carbon-supporting materials. In this report, we describe in detail the mechanism of the stability improvement of carbon blacks (CBs; Vulcan and Ketjen) by coating with polybenzimidazole (PBI). Nitrogen adsorption experiments reveal that the PBI coating of CBs results in the capping of the gates of the CB-micropores by the PBI. Since the surface of the micropores inside the CBs are inherently highly oxidized, the capping of such pores effectively prevents the penetration of the electrolyte into the pore and works to avoid the further oxidation of interior of the micropore, which is proved by cyclic voltammogram measurements. Above mechanism agrees very well with the dramatic enhancement of the durability of the membrane electrode assembly fabricated using Pt on the PBI-coated CBs as an electrocatalyst compared to the conventional Pt/CB (PBI-non coated) catalyst.

  15. Layer-by-layer self-assembled mesoporous PEDOT-PSS and carbon black hybrid films for platinum free dye-sensitized-solar-cell counter electrodes.

    Science.gov (United States)

    Kitamura, Koji; Shiratori, Seimei

    2011-05-13

    A thin film of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonic acid) (PEDOT-PSS), which is an alternative cathodic catalyst for Pt in dye-sensitized solar cells, was prepared using the layer-by-layer self-assembly method (LbL). The film is highly adhesive to the substrate and has a controllable thickness. Therefore, the PEDOT-PSS film prepared using LbL is expected have high performance and durability as a counter electrode. Moreover, when carbon black was added to the PEDOT-PSS solution, highly mesoporous PEDOT-PSS and carbon black hybrid films were obtained. These films showed high cathodic activity. In this study, we investigated the change in morphology in the obtained film with increasing carbon black content, and the influence of the porosity and thickness on the performance of the cells. In this study, a Pt-free counter electrode with performance similar to that of Pt-based counter electrodes was successfully fabricated. The achieved efficiency of 4.71% was only a factor of 8% lower than that of the cell using conventional thermally deposited Pt on fluorine-doped tin oxide glass counter electrodes.

  16. Antagonistic effects of black tea against gamma radiation-induced oxidative damage to normal lymphocytes in comparison with cancerous K562 cells.

    Science.gov (United States)

    Ghosh, Debjani; Dey, Subrata Kumar; Saha, Chabita

    2014-11-01

    The potential of naturally occurring antioxidants to reduce the cellular oxidative damage induced by ionizing radiation has been studied for more than a decade for their pharmacological application during cancer treatment. It is already known that radioprotective efficacy of phytochemicals might influence various end points of radiation damage. Flavonoids are well-known natural radioprotectors, and their biological effects depend upon their chemical structure. In the present study, radioprotective effect of black tea rich in flavonoids was evaluated against gamma radiation-induced oxidative damage on normal lymphocytes and compared with erythroleukemic K562 cells. Pre-treatment with black tea extract (BTE) significantly reduced radiation-induced loss of cell viability, generation of reactive oxygen species, mitochondrial dysfunction, activation of caspase-3 and apoptosis in normal lymphocytes compared to K562 cells. BTE also regulates the activity of endogenous antioxidant enzymes. The changes in the mRNA expression of bax, bcl2, p53 and Nrf2 were also followed to evaluate regulation of radiation-induced apoptosis by BTE. These findings suggest that black tea may have the potential of a natural radioprotective agent which can be used as adjunct with radiation during cancer treatment.

  17. Resistance to Varroa destructor (Mesostigmata: Varroidae) when mite-resistant queen honey bees (Hymenoptera: Apidae) were free-mated with unselected drones.

    Science.gov (United States)

    Harbo, J R; Harris, J W

    2001-12-01

    This study demonstrated (1) that honey bees, Apis mellifera L, can express a high level of resistance to Varroa destructor Anderson & Trueman when bees were selected for only one resistant trait (suppression of mite reproduction); and (2) that a significant level of mite-resistance was retained when these queens were free-mated with unselected drones. The test compared the growth of mite populations in colonies of bees that each received one of the following queens: (1) resistant--queens selected for suppression of mite reproduction and artificially inseminated in Baton Rouge with drones from similarly selected stocks; (2) resistant x control--resistant queens, as above, produced and free-mated to unselected drones by one of four commercial queen producers; and (3) control--commercial queens chosen by the same four queen producers and free-mated as above. All colonies started the test with approximately 0.9 kg of bees that were naturally infested with approximately 650 mites. Colonies with resistant x control queens ended the 115-d test period with significantly fewer mites than did colonies with control queens. This suggests that beekeepers can derive immediate benefit from mite-resistant queens that have been free-mated to unselected drones. Moreover, the production and distribution of these free-mated queens from many commercial sources may be an effective way to insert beneficial genes into our commercial population of honey bees without losing the genetic diversity and the useful beekeeping characteristics of this population.

  18. Ly-1 B cells and disease activity in (New Zealand black x New Zealand white)F1 mice. Effect of total lymphoid irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farinas, M.C.; Stall, A.M.; Solovera, J.J.; Tarlinton, D.M.; Herzenberg, L.A.; Strober, S. (Stanford Univ. School of Medicine, CA (USA))

    1990-04-01

    The treatment of female (New Zealand black x New Zealand white)F1 mice with total lymphoid irradiation resulted in a prolonged remission of autoimmune disease activity. Total lymphoid irradiation-treated mice also showed a marked reduction of Ly-1 B cells, which lasted up to 3 months. The subsequent return of Ly-1 B cells to preirradiation levels was not associated with a simultaneous return of disease when measured by parameters such as IgG anti-DNA antibodies and spontaneous secretion of IgG by splenic cells. In cell sorting experiments, most of the cells spontaneously secreting IgG were found within the Ly-1- (CD5-) splenic B cell population.

  19. Platinum-carbon black-titanium dioxide nanocomposite electrocatalysts for fuel cell applications

    Indian Academy of Sciences (India)

    Satheesh Sambandam; Vinodh Valluri; Wilaiwan Chanmanee; Norma R De Tacconi; Wesley A Wampler; Wen-Yuan Lin; Thomas F Carlson; Vijay Ramani; Krishnan Rajeshwar

    2009-09-01

    New-generation Pt/C-TiO2 nanocomposite electrocatalysts for fuel cells, prepared by a heterogeneous photocatalytic method, have been characterized using techniques such as cyclic voltammetry, rotating disk electrode (RDE) voltammetry, and electrochemical impedance spectroscopy (EIS). Importantly, galvanostatic data confirm the superior stability of these materials against corrosion under anodic polarization conditions relative to commercial benchmark fuel cell electrocatalysts. EIS spectra from ETEK 5, SIDCAT 405 and SIDCAT 410 membrane electrode assemblies (MEAs) were fit to a Randles equivalent circuit with a Warburg element to show the presence of O2 transport limitation arising from the use of thicker electrodes (lower Pt loading on carbon). The use of a constant phase element (CPE) instead of pure capacitor was justified from the fit procedure as CPE represents the porous electrode system more precisely with its distributive elements. EIS spectra from Tanaka, SIDCAT 451 and SIDCAT 452 MEAs (thinner electrodes) were fit to a Randles circuit with a pure capacitor and no Warburg element. The use of a transmission line model for fitting these data independently provided information about the catalyst layer resistance while all other parameters matched well with that of the Randles circuit. The effective proton transport in cathodes was quantified using polarization data for both classes of MEAs. Trends in the previously reported performance of MEAs prepared using these electrocatalysts were justified based on the relative contributions of kinetic, Ohmic and mass transfer losses to the overall overpotential, which in turn were estimated from impedance and polarization data analyses.

  20. Effects of ultraviolet-visible irradiation in the presence of melanin isolated from human black or red hair upon Ehrlich ascites carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Menon, I.A.; Persad, S.; Ranadive, N.S.; Haberman, H.F.

    1983-07-01

    The present study is an attempt to investigate the possibility that ultraviolet irradiation in the presence of pheomelanin may be more harmful to cells than the irradiation in the presence of eumelanin. The effects of UV-visible irradiation upon Ehrlich ascites carcinoma cells in the presence of the melanin isolated from human black hair (eumelanin) or from red hair (pheomelanin) were investigated. Irradiation of these cells was found to produce cell lysis, as observed by leakage of 51Cr from labeled cells and intracellular lactic dehydrogenase from the cells and decrease in cell viability demonstrated by the trypan blue exclusion test. The three parameters were quantitatively parallel to one another under various experimental conditions, namely different periods of irradiation and irradiation in the presence of different concentrations of melanin. The above effects were more pronounced when the irradiation was carried out in the presence of melanin from red hair than in the presence of black-hair melanin. In the absence of either melanin, the irradiation did not produce any significant effect in cell viability or cell lysis. Irradiation of the cells in the presence of red-hair melanin also decreased the transplantability of these cells. These observations clearly show that irradiation of cells in the presence of pheomelanin could produce cytotoxic effects. The present experimental design may have application in the development of in vitro models for the study of UV radiation-induced cutaneous carcinogenesis. The reactions of pheomelanin may be related to the susceptibility of ''Celtic'' skin to UV radiation-induced skin damage and carcinogenesis.

  1. CELL DEATH DIFFERENTIATION IN BLACK HEADED RAMS SPERMATOZOA, USING FLUORESCENT LABELED ANNEXIN V

    Directory of Open Access Journals (Sweden)

    M Ivanova-Kicheva

    2008-11-01

    Full Text Available Double staining kit of Annexin V Cy3.18/6-CFDA was used to investigate the changes in phospholipide asymmetry after treating sperm cells with dexamethasone. The % of spermatozoa with registered translocation of PS in treated with dexamethazone groups at the 10-th min and in control no treated varied from 2.74%±0.65 to 2.30%±0.89. After the 5 hour of incubation these % increased to 39.83±3.33 for the treated group and 23.44±1.12 for the control. It was concluded that Annexin V binding assay is more sensitive in the detection of deterioration in membrane function than other conventional methods such as motility analysis and supravital techniques.

  2. Sublimation of Exposed Snow Queen Surface Water Ice as Observed by the Phoenix Mars Lander

    Science.gov (United States)

    Markiewicz, W. J.; Keller, H. U.; Kossacki, K. J.; Mellon, M. T.; Stubbe, H. F.; Bos, B. J.; Woida, R.; Drube, L.; Leer, K.; Madsen, M. B.; Goetz, W.; El Maarry, M. R.; Smith, P.

    2008-12-01

    One of the first images obtained by the Robotic Arm Camera on the Mars Phoenix Lander was that of the surface beneath the spacecraft. This image, taken on sol 4 (Martian day) of the mission, was intended to check the stability of the footpads of the lander and to document the effect the retro-rockets had on the Martian surface. Not completely unexpected the image revealed an oval shaped, relatively bright and apparently smooth object, later named Snow Queen, surrounded by the regolith similar to that already seen throughout the landscape of the landing site. The object was suspected to be the surface of the ice table uncovered by the blast of the retro-rockets during touchdown. High resolution HiRISE images of the landing site from orbit, show a roughly circular dark region of about 40 m diameter with the lander in the center. A plausible explanation for this region being darker than the rest of the visible Martian Northern Planes (here polygonal patterns) is that a thin layer of the material ejected by the retro-rockets covered the original surface. Alternatively the thrusters may have removed the fine surface dust during the last stages of the descent. A simple estimate requires that about 10 cm of the surface material underneath the lander is needed to be ejected and redistributed to create the observed dark circular region. 10 cm is comparable to 4-5 cm predicted depth at which the ice table was expected to be found at the latitude of the Phoenix landing site. The models also predicted that exposed water ice should sublimate at a rate not faster but probably close to 1 mm per sol. Snow Queen was further documented on sols 5, 6 and 21 with no obvious changes detected. The following time it was imaged was on sol 45, 24 sols after the previous observation. This time some clear changes were obvious. Several small cracks, most likely due to thermal cycling and sublimation of water ice appeared. Nevertheless, the bulk of Snow Queen surface remained smooth. The next

  3. Binder-free carbon black/stainless steel mesh composite electrode for high-performance anode in microbial fuel cells

    Science.gov (United States)

    Zheng, Suqi; Yang, Fangfang; Chen, Shuiliang; Liu, Lang; Xiong, Qi; Yu, Ting; Zhao, Feng; Schröder, Uwe; Hou, Haoqing

    2015-06-01

    Carbon black/stainless steel mesh (CB/SSM) composite electrodes were developed as high-performance anodes of microbial fuel cell (MFC) by using a binder-free dipping/drying method. The acid-treatment and thin layer of CB coating greatly improved the microbial adhesion of the electrode surface and facilitated the electron transfer between the bacteria and the electrode surface. As a result, a single-layer CB/SSM anode with thickness of 0.3 mm could generate a projected current density of about 1.53 ± 0.15 mA cm-2 and volumetic current density of 51.0 ± 5.0 mA cm-3, which was much higher than that of the bare SSM anode and conventional carbon felt anode with thickness of 2 mm. Moreover, three-dimensional (3D) CB/SSM electrode could be prepared by simple folding the singe-layer SSM, and produced a projected current density to 10.07 ± 0.88 mA cm-2 and a volumetric current density of 18.66 ± 1.63 mA cm-3. The MFC equipped with the 3D-CB/SSM anode produced a high maximum power density of 3215 ± 80 mW m-2. The CB/SSM electrodes showed good mechanical and electrical properties, excellent microbial adhesion; it represented a high-performance, low-cost electrode material that is easy to fabricate and scale-up.

  4. Black tea

    Science.gov (United States)

    ... combination.Talk with your health provider.Birth control pills (Contraceptive drugs)Black tea contains caffeine. The body breaks down caffeine to get rid of it. Birth control pills can decrease how quickly the body breaks down ...

  5. 76 FR 59375 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Amendments to the Queen Conch and...

    Science.gov (United States)

    2011-09-26

    ..., Gulf of Mexico, and South Atlantic; Amendments to the Queen Conch and Reef Fish Fishery Management.... In contrast, the wenchman is presently included as a member of Snapper Unit 2 but clusters...

  6. Multichannel Seismic Reflection Data - SCAR - Queen Maud Land - 1985-1986, SDLS CD-ROM vol 22

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1985-86 in the Queen Maud Land region, Antarctica, by the Japan National Oil...

  7. Contrasting roles for CD4 vs. CD8 T-cells in a murine model of virally induced "T1 black hole" formation.

    Directory of Open Access Journals (Sweden)

    Istvan Pirko

    Full Text Available MRI is sensitive to tissue pathology in multiple sclerosis (MS; however, most lesional MRI findings have limited correlation with disability. Chronic T1 hypointense lesions or "T1 black holes" (T1BH, observed in a subset of MS patients and thought to represent axonal damage, show moderate to strong correlation with disability. The pathogenesis of T1BH remains unclear. We previously reported the first and as of yet only model of T1BH formation in the Theiler's murine encephalitis virus induced model of acute CNS neuroinflammation induced injury, where CD8 T-cells are critical mediators of axonal damage and related T1BH formation. The purpose of this study was to further analyze the role of CD8 and CD4 T-cells through adoptive transfer experiments and to determine if the relevant CD8 T-cells are classic epitope specific lymphocytes or different subsets. C57BL/6 mice were used as donors and RAG-1 deficient mice as hosts in our adoptive transfer experiments. In vivo 3-dimensional MRI images were acquired using a 7 Tesla small animal MRI system. For image analysis, we used semi-automated methods in Analyze 9.1; transfer efficiency was monitored using FACS of brain infiltrating lymphocytes. Using a peptide depletion method, we demonstrated that the majority of CD8 T-cells are classic epitope specific cytotoxic cells. CD8 T-cell transfer successfully restored the immune system's capability to mediate T1BH formation in animals that lack adaptive immune system, whereas CD4 T-cell transfer results in an attenuated phenotype with significantly less T1BH formation. These findings demonstrate contrasting roles for these cell types, with additional evidence for a direct pathogenic role of CD8 T-cells in our model of T1 black hole formation.

  8. Contrasting roles for CD4 vs. CD8 T-cells in a murine model of virally induced "T1 black hole" formation.

    Science.gov (United States)

    Pirko, Istvan; Chen, Yi; Lohrey, Anne K; McDole, Jeremiah; Gamez, Jeffrey D; Allen, Kathleen S; Pavelko, Kevin D; Lindquist, Diana M; Dunn, R Scott; Macura, Slobodan I; Johnson, Aaron J

    2012-01-01

    MRI is sensitive to tissue pathology in multiple sclerosis (MS); however, most lesional MRI findings have limited correlation with disability. Chronic T1 hypointense lesions or "T1 black holes" (T1BH), observed in a subset of MS patients and thought to represent axonal damage, show moderate to strong correlation with disability. The pathogenesis of T1BH remains unclear. We previously reported the first and as of yet only model of T1BH formation in the Theiler's murine encephalitis virus induced model of acute CNS neuroinflammation induced injury, where CD8 T-cells are critical mediators of axonal damage and related T1BH formation. The purpose of this study was to further analyze the role of CD8 and CD4 T-cells through adoptive transfer experiments and to determine if the relevant CD8 T-cells are classic epitope specific lymphocytes or different subsets. C57BL/6 mice were used as donors and RAG-1 deficient mice as hosts in our adoptive transfer experiments. In vivo 3-dimensional MRI images were acquired using a 7 Tesla small animal MRI system. For image analysis, we used semi-automated methods in Analyze 9.1; transfer efficiency was monitored using FACS of brain infiltrating lymphocytes. Using a peptide depletion method, we demonstrated that the majority of CD8 T-cells are classic epitope specific cytotoxic cells. CD8 T-cell transfer successfully restored the immune system's capability to mediate T1BH formation in animals that lack adaptive immune system, whereas CD4 T-cell transfer results in an attenuated phenotype with significantly less T1BH formation. These findings demonstrate contrasting roles for these cell types, with additional evidence for a direct pathogenic role of CD8 T-cells in our model of T1 black hole formation.

  9. Raiders from the sky: slavemaker founding queens select for aggressive host colonies

    Science.gov (United States)

    Pamminger, Tobias; Modlmeier, Andreas P.; Suette, Stefan; Pennings, Pleuni S.; Foitzik, Susanne

    2012-01-01

    Reciprocal selection pressures in host–parasite systems drive coevolutionary arms races that lead to advanced adaptations in both opponents. In the interactions between social parasites and their hosts, aggression is one of the major behavioural traits under selection. In a field manipulation, we aimed to disentangle the impact of slavemaking ants and nest density on aggression of Temnothorax longispinosus ants. An early slavemaker mating flight provided us with the unique opportunity to study the influence of host aggression and demography on founding decisions and success. We discovered that parasite queens avoided colony foundation in parasitized areas and were able to capture more brood from less aggressive host colonies. Host colony aggression remained consistent over the two-month experiment, but did not respond to our manipulation. However, as one-fifth of all host colonies were successfully invaded by parasite queens, slavemaker nest foundation acts as a strong selection event selecting for high aggression in host colonies. PMID:22809720

  10. Queen Christina’s esoteric interests as a background to her Platonic Academies

    Directory of Open Access Journals (Sweden)

    Susanna Åkerman

    2008-01-01

    Full Text Available In 1681 the blind quietist, Francois Malaval, stated that Queen Christina of Sweden late in life had ‘given up’ [Hermes] Trismegistos and the Platonists, in favour of the Church fathers. The statement does not explain what role the Church fathers were to play in her last years, but it does show that Christina really had been interested in the rather elitist and esoteric doctrine of Hermetic Platonic Christianity. In this article the author looks at her library to show the depth of this Hermetic involvement. Her interest serves as a background to her life as ex-queen in Italy after her famous abdication from the Swedish throne in 1654, when she was 27 years old.

  11. Lower disease infections in honeybee (Apis mellifera) colonies headed by polyandrous vs monandrous queens

    Science.gov (United States)

    Tarpy, David R.; Seeley, Thomas D.

    2006-04-01

    We studied the relationship between genetic diversity and disease susceptibility in honeybee colonies living under natural conditions. To do so, we created colonies in which each queen was artificially inseminated with sperm from either one or ten drones. Of the 20 colonies studied, 80% showed at least one brood disease. We found strong differences between the two types of colonies in the infection intensity of chalkbrood and in the total intensity of all brood diseases (chalkbrood, sacbrood, American foulbrood, and European foulbrood) with both variables lower for the colonies with higher genetic diversity. Our findings demonstrate that disease can be an important factor in the ecology of honeybee colonies and they provide strong support for the disease hypothesis for the evolution of polyandry by social insect queens.

  12. Idiopathic brood disease syndrome and queen events as precursors of colony mortality in migratory beekeeping operations in the eastern United States.

    Science.gov (United States)

    vanEngelsdorp, Dennis; Tarpy, David R; Lengerich, Eugene J; Pettis, Jeffery S

    2013-02-01

    Using standard epidemiological methods, this study set out to quantify the risk associated with exposure to easily diagnosed factors on colony mortality and morbidity in three migratory beekeeping operations. Fifty-six percent of all colonies monitored during the 10-month period died. The relative risk (RR) that a colony would die over the short term (∼50 days) was appreciably increased in colonies diagnosed with Idiopathic Brood Disease Syndrome (IBDS), a condition where brood of different ages appear molten on the bottom of cells (RR=3.2), or with a "queen event" (e.g., evidence of queen replacement or failure; RR=3.1). We also found that several risk factors-including the incidence of a poor brood pattern, chalkbood (CB), deformed wing virus (DWV), sacbrood virus (SBV), and exceeding the threshold of 5 Varroa mites per 100 bees-were differentially expressed in different beekeeping operations. Further, we found that a diagnosis of several factors were significantly more or less likely to be associated with a simultaneous diagnosis of another risk factor. These finding support the growing consensus that the causes of colony mortality are multiple and interrelated.

  13. Intrinsic worker mortality depends on behavioral caste and the queens' presence in a social insect.

    Science.gov (United States)

    Kohlmeier, Philip; Negroni, Matteo Antoine; Kever, Marion; Emmling, Stefanie; Stypa, Heike; Feldmeyer, Barbara; Foitzik, Susanne

    2017-04-01

    According to the classic life history theory, selection for longevity depends on age-dependant extrinsic mortality and fecundity. In social insects, the common life history trade-off between fecundity and longevity appears to be reversed, as the most fecund individual, the queen, often exceeds workers in lifespan several fold. But does fecundity directly affect intrinsic mortality also in social insect workers? And what is the effect of task on worker mortality? Here, we studied how social environment and behavioral caste affect intrinsic mortality of ant workers. We compared worker survival between queenless and queenright Temnothorax longispinosus nests and demonstrate that workers survive longer under the queens' absence. Temnothorax ant workers fight over reproduction when the queen is absent and dominant workers lay eggs. Worker fertility might therefore increase lifespan, possibly due to a positive physiological link between fecundity and longevity, or better care for fertile workers. In social insects, division of labor among workers is age-dependant with young workers caring for the brood and old ones going out to forage. We therefore expected nurses to survive longer than foragers, which is what we found. Surprisingly, inactive inside workers showed a lower survival than nurses but comparable to that of foragers. The reduced longevity of inactive workers could be due to them being older than the nurses, or due to a positive effect of activity on lifespan. Overall, our study points to behavioral caste-dependent intrinsic mortality rates and a positive association between fertility and longevity not only in queens but also in ant workers.

  14. An observation study on the effects of queen age on some characteristics of honey bee colonies

    Directory of Open Access Journals (Sweden)

    Ibrahim Çakmak

    2010-01-01

    Full Text Available This study was conducted to determine the effects of the queen’s age on performance of the honeybee (A. mellifera anatoliaca colonies at nomad beekeeping conditions. Performances of the colonies, which had 0, 1, 2 and 3 year-old queens, were compared. The number of combs, brood areas, wintering ability survival rate and honey yield were determined as performance criteria. The average number of combs with bees throughout the experiment in Group I, Group II, Group III and Group IV was 10.92±0.78, 14.68±0.55, 10.10±0.60, 7.88±0.45 number combs/colony; the average of brood areas was 3078±372.5 cm2, 3668±460.3 cm2, 2215±294.0 cm2, 1665.38±241.8 cm2; the average of wintering ability was 84.3±2.9%, 88.0±3.7%, 46.6±19.0%, 26.8±16.5%; the survival rate was 100%, 100%, 60%, 40%; and the average of honey yields was 31.4±1.89 kg, 41.5±1.05 kg, 20.4±2.62 kg and 12.0±1.41 kg per colony, respectively. A significant and negative correlation between queen age and brood production (r=-80.2, colony strength (r=-62.5, wintering ability (r=-66 and honey yield (r=-75.6 were calculated (P<0.01. The colonies headed by young queens had more brood areas, longer worker colony population, better wintering ability and greater honey yield in comparison to colonies headed by old queens.

  15. Conservation and modification of genetic and physiological toolkits underpinning diapause in bumble bee queens.

    Science.gov (United States)

    Amsalem, Etya; Galbraith, David A; Cnaani, Jonathan; Teal, Peter E A; Grozinger, Christina M

    2015-11-01

    Diapause is the key adaptation allowing insects to survive unfavourable conditions and inhabit an array of environments. Physiological changes during diapause are largely conserved across species and are hypothesized to be regulated by a conserved suite of genes (a 'toolkit'). Furthermore, it is hypothesized that in social insects, this toolkit was co-opted to mediate caste differentiation between long-lived, reproductive, diapause-capable queens and short-lived, sterile workers. Using Bombus terrestris queens, we examined the physiological and transcriptomic changes associated with diapause and CO2 treatment, which causes queens to bypass diapause. We performed comparative analyses with genes previously identified to be associated with diapause in the Dipteran Sarcophaga crassipalpis and with caste differentiation in bumble bees. As in Diptera, diapause in bumble bees is associated with physiological and transcriptional changes related to nutrient storage, stress resistance and core metabolic pathways. There is a significant overlap, both at the level of transcript and gene ontology, between the genetic mechanisms mediating diapause in B. terrestris and S. crassipalpis, reaffirming the existence of a conserved insect diapause genetic toolkit. However, a substantial proportion (10%) of the differentially regulated transcripts in diapausing queens have no clear orthologs in other species, and key players regulating diapause in Diptera (juvenile hormone and vitellogenin) appear to have distinct functions in bumble bees. We also found a substantial overlap between genes related to caste determination and diapause in bumble bees. Thus, our studies demonstrate an intriguing interplay between pathways underpinning adaptation to environmental extremes and the evolution of sociality in insects.

  16. Olfactory attraction of Scaptotrigona mexicana drones to their virgin queen volatiles

    OpenAIRE

    2011-01-01

    International audience; Drone congregations are a ubiquitous phenomenon described in several species of stingless bees and extensively studied in the honeybee, Apis mellifera. In meliponaries of Scaptotrigona mexicana, it is usual to observe drones forming such congregations close to the nests, apparently waiting for a virgin queen for mating. We hypothesize that drones of this species, similarly to those of A. mellifera and the stingless bee Scaptotrigona postica, use olfactory signals to de...

  17. Impact of chronic neonicotinoid exposure on honeybee colony performance and queen supersedure.

    Directory of Open Access Journals (Sweden)

    Christoph Sandrock

    Full Text Available BACKGROUND: Honeybees provide economically and ecologically vital pollination services to crops and wild plants. During the last decade elevated colony losses have been documented in Europe and North America. Despite growing consensus on the involvement of multiple causal factors, the underlying interactions impacting on honeybee health and colony failure are not fully resolved. Parasites and pathogens are among the main candidates, but sublethal exposure to widespread agricultural pesticides may also affect bees. METHODOLOGY/PRINCIPAL FINDINGS: To investigate effects of sublethal dietary neonicotinoid exposure on honeybee colony performance, a fully crossed experimental design was implemented using 24 colonies, including sister-queens from two different strains, and experimental in-hive pollen feeding with or without environmentally relevant concentrations of thiamethoxam and clothianidin. Honeybee colonies chronically exposed to both neonicotinoids over two brood cycles exhibited decreased performance in the short-term resulting in declining numbers of adult bees (-28% and brood (-13%, as well as a reduction in honey production (-29% and pollen collections (-19%, but colonies recovered in the medium-term and overwintered successfully. However, significantly decelerated growth of neonicotinoid-exposed colonies during the following spring was associated with queen failure, revealing previously undocumented long-term impacts of neonicotinoids: queen supersedure was observed for 60% of the neonicotinoid-exposed colonies within a one year period, but not for control colonies. Linked to this, neonicotinoid exposure was significantly associated with a reduced propensity to swarm during the next spring. Both short-term and long-term effects of neonicotinoids on colony performance were significantly influenced by the honeybees' genetic background. CONCLUSIONS/SIGNIFICANCE: Sublethal neonicotinoid exposure did not provoke increased winter losses. Yet

  18. Port Isabel (GIWW) Channel Improvements at the Queen Isabella Causeway. Laguna Madre, Texas, Navigation Improvement Project

    Science.gov (United States)

    2009-09-01

    ER D C/ CH L TR -0 9 -1 3 Port Isabel (GIWW) Channel Improvements at the Queen Isabella Causeway Laguna Madre , Texas, Navigation...Causeway Laguna Madre , Texas, Navigation Improvement Project Timothy W. Shelton, P.E. and Dennis Webb, P.E. Coastal and Hydraulics Laboratory U.S...distribution is unlimited. Prepared for U.S. Army Corps of Engineer District, Galveston Galveston, TX 77550 ERDC/CHL TR-09-13 ii Abstract: Laguna Madre is

  19. Lactobacillus vespulae sp. nov., isolated from gut of a queen wasp (Vespula vulgaris).

    Science.gov (United States)

    Hoang, Van-An; Kim, Yeon-Ju; Nguyen, Ngoc-Lan; Kim, Si-Kwan; Yang, Deok-Chun

    2015-10-01

    A Gram-stain-positive, oxidase- and catalase-negative, rod-shaped, facultatively anaerobic bacterial strain, DCY75T, was isolated from a queen wasp (Vespula vulgaris). Growth occurred at 4–37 °C (optimum, 30 °C), at pH 3.5–8.0 (optimum, pH 5.0–6.0) and with ≤ 7.0 % (w/v) NaCl. Strain DCY75T produced gas during growth on glucose. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain DCY75T belonged to the genus Lactobacillus and was closely related to Lactobacillus sanfranciscensis ATCC 27651T and Lactobacillus lindneri DSM 20690T at sequence similarities of 96.7 and 96.4 %, respectively. A comparison of two housekeeping genes, pheS and rpoA, revealed that strain DCT75T was well separated from other species of the genus Lactobacillus. Strain DCY75T produced d- and l-lactic acid isomers in a ratio of 22.5 : 77.5 (v/v). The major fatty acids were summed feature 8 (comprising C18 :  1ω7c and/or C18 : 1ω6c), C16 : 0, C18 : 1ω9c and C18 : 0.The peptidoglycan structure was of the A4α (l-Lys–d-Asp) type. Cell-wall sugars were glucose, galactose and ribose. The DNA G+C content was 35.5 ± 1.3 mol%. Based on phenotypic and genotypic properties, strain DCY75T represents a novel species of the genus Lactobacillus, for which the name Lactobacillus vespulae sp. nov. is proposed. The type strain is DCY75T ( = KCTC 21023T = JCM 19742T).

  20. Does the Red Queen reign in the kingdom of digital organisms?

    CERN Document Server

    Wilke, C O

    2003-01-01

    In competition experiments between two RNA viruses of equal or almost equal fitness, often both strains gain in fitness before one eventually excludes the other. This observation has been linked to the Red Queen effect, which describes a situation in which organisms have to constantly adapt just to keep their status quo. I carried out experiments with digital organisms (self-replicating computer programs) in order to clarify how the competing strains' location in fitness space influences the Red-Queen effect. I found that gains in fitness during competition were prevalent for organisms that were taken from the base of a fitness peak, but absent or rare for organisms that were taken from the top of a peak or from a considerable distance away from the nearest peak. In the latter two cases, either neutral drift and loss of the fittest mutants or the waiting time to the first beneficial mutation were more important factors. Moreover, I found that the Red-Queen dynamic in general led to faster exclusion than the o...

  1. Genomewide analysis indicates that queen larvae have lower methylation levels in the honey bee ( Apis mellifera)

    Science.gov (United States)

    Shi, Yuan Yuan; Yan, Wei Yu; Huang, Zachary Y.; Wang, Zi Long; Wu, Xiao Bo; Zeng, Zhi Jiang

    2013-02-01

    The honey bee is a social insect characterized by caste differentiation, by which a young larva can develop into either a queen or a worker. Despite possessing the same genome, queen and workers display marked differences in reproductive capacity, physiology, and behavior. Recent studies have shown that DNA methylation plays important roles in caste differentiation. To further explore the roles of DNA methylation in this process, we analyzed DNA methylome profiles of both queen larvae (QL) and worker larvae (WL) of different ages (2, 4, and 6 day old), by using methylated DNA immunoprecipitation-sequencing (meDIP-seq) technique. The global DNA methylation levels varied between the larvae of two castes. DNA methylation increased from 2-day- to 4-day-old QL and then decreased in 6-day-old larvae. In WL, methylation levels increased with age. The methylcytosines in both larvae were enriched in introns, followed by coding sequence (CDS) regions, CpG islands, 2 kbp downstream and upstream of genes, and 5' and 3' untranslated regions (UTRs). The number of differentially methylated genes (DMGs) in 2-, 4-, and 6-day-old QL and WL was 725, 3,013, and 5,049, respectively. Compared to 4- and 6-day-old WL, a large number of genes in QL were downmethylated, which were involved in many processes including development, reproduction, and metabolic regulation. In addition, some DMGs were concerned with caste differentiation.

  2. The foundress's dilemma: group selection for cooperation among queens of the harvester ant, Pogonomyrmex californicus.

    Science.gov (United States)

    Shaffer, Zachary; Sasaki, Takao; Haney, Brian; Janssen, Marco; Pratt, Stephen C; Fewell, Jennifer H

    2016-07-28

    The evolution of cooperation is a fundamental problem in biology, especially for non-relatives, where indirect fitness benefits cannot counter within-group inequalities. Multilevel selection models show how cooperation can evolve if it generates a group-level advantage, even when cooperators are disadvantaged within their group. This allows the possibility of group selection, but few examples have been described in nature. Here we show that group selection can explain the evolution of cooperative nest founding in the harvester ant Pogonomyrmex californicus. Through most of this species' range, colonies are founded by single queens, but in some populations nests are instead founded by cooperative groups of unrelated queens. In mixed groups of cooperative and single-founding queens, we found that aggressive individuals had a survival advantage within their nest, but foundress groups with such non-cooperators died out more often than those with only cooperative members. An agent-based model shows that the between-group advantage of the cooperative phenotype drives it to fixation, despite its within-group disadvantage, but only when population density is high enough to make between-group competition intense. Field data show higher nest density in a population where cooperative founding is common, consistent with greater density driving the evolution of cooperative foundation through group selection.

  3. Quantum chemical study on the stability of honeybee queen pheromone against atmospheric factors.

    Science.gov (United States)

    Shi, Rongwei; Liu, Fanglin

    2016-06-01

    The managed honeybee, Apis mellifera, has been experienced a puzzling event, termed as colony collapse disorder (CCD), in which worker bees abruptly disappear from their hives. Potential factors include parasites, pesticides, malnutrition, and environmental stresses. However, so far, no definitive relationship has been established between specific causal factors and CCD events. Here we theoretically test whether atmospheric environment could disturb the chemical communication between the queen and their workers in a colony. A quantum chemistry method has been used to investigate for the stability of the component of A. mellifera queen mandibular pheromone (QMP), (E)-9-keto-2-decenoic acid (9-ODA), against atmospheric water and free radicals. The results show that 9-ODA is less likely to react with water due to the high barrier heights (~36.5 kcal · mol(-1)) and very low reaction rates. However, it can easily react with triplet oxygen and hydroxyl radicals because of low or negative energy barriers. Thus, the atmospheric free radicals may disturb the chemical communication between the queen and their daughters in a colony. Our pilot study provides new insight for the cause of CCD, which has been reported throughout the world.

  4. Role of relative humidity in colony founding and queen survivorship in two carpenter ant species.

    Science.gov (United States)

    Mankowski, Mark E; Morrell, J J

    2011-06-01

    Conditions necessary for optimal colony foundation in two carpenter ant species, Camponotus modoc Wheeler and Camponotus vicinus Mayr, were studied. Camponotus modoc and C. vicinus queens were placed in Douglas-fir, Pseudotsuga menziesii (Mirb. Franco) and Styrofoam blocks conditioned in sealed chambers at 70, 80, or 100% RH. Nanitic workers produced after 12 wk were used to assess the effects of substrate and moisture content on colony initiation. Queens of C. vicinus in Douglas-fir and Styrofoam produced worker numbers that did not differ significantly with moisture content; however, the number of colonies initiated by C. modoc differed significantly with moisture content. The results indicate that colony founding in C. vicinus is less sensitive to moisture content than C. modoc for Douglas-fir and Styrofoam. In another test, groups of queens of each species were exposed to 20, 50, 70, and 100% RH and the time until 50% mortality occurred was recorded for each species. C. vicinus lived significantly longer at each of the test humidities than C. modoc, suggesting that the former species is adapted to better survive under xeric conditions.

  5. West Pearl Queen CO2 sequestration pilot test and modeling project 2006-2008.

    Energy Technology Data Exchange (ETDEWEB)

    Engler, Bruce Phillip; Cooper, Scott Patrick; Symons, Neill Phillip; Bartel, Lewis Clark; Byrer, Charles (National Energy Laboratory, Morgantown, WV); Elbring, Gregory Jay; McNemar, Andrea (National Energy Laboratory, Morgantown, WV); Aldridge, David Franklin; Lorenz, John Clay

    2008-08-01

    The West Pearl Queen is a depleted oil reservoir that has produced approximately 250,000 bbl of oil since 1984. Production had slowed prior to CO{sub 2} injection, but no previous secondary or tertiary recovery methods had been applied. The initial project involved reservoir characterization and field response to injection of CO{sub 2}; the field experiment consisted of injection, soak, and venting. For fifty days (December 20, 2002, to February 11, 2003) 2090 tons of CO{sub 2} were injected into the Shattuck Sandstone Member of the Queen Formation at the West Pearl Queen site. This technical report highlights the test results of the numerous research participants and technical areas from 2006-2008. This work included determination of lateral extents of the permeability units using outcrop observations, core results, and well logs. Pre- and post-injection 3D seismic data were acquired. To aid in interpreting seismic data, we performed numerical simulations of the effects of CO{sub 2} replacement of brine where the reservoir model was based upon correlation lengths established by the permeability studies. These numerical simulations are not intended to replicate field data, but to provide insight of the effects of CO{sub 2}.

  6. Queen of Peace Nursing Home, Churchfield, Knock, Mayo.

    LENUS (Irish Health Repository)

    Nowostawska, Malgorzata

    2011-04-08

    Abstract Background The use of silica coated magnetic nanoparticles as contrast agents has resulted in the production of highly stable, non-toxic solutions that can be manipulated via an external magnetic field. As a result, the interaction of these nanocomposites with cells is of vital importance in understanding their behaviour and biocompatibility. Here we report the preparation, characterisation and potential application of new "two-in-one" magnetic fluorescent nanocomposites composed of silica-coated magnetite nanoparticles covalently linked to a porphyrin moiety. Method The experiments were performed by administering porphyrin functionalised silica-coated magnetite nanoparticles to THP-1 cells, a human acute monocytic leukaemia cell line. Cells were cultured in RPMI 1640 medium with 25 mM HEPES supplemented with heat-inactivated foetal bovine serum (FBS). Results We have synthesised, characterised and analysed in vitro, a new multimodal (magnetic and fluorescent) porphyrin magnetic nanoparticle composite (PMNC). Initial co-incubation experiments performed with THP-1 macrophage cells were promising; however the PMNC photobleached under confocal microscopy study. β-mercaptoethanol (β-ME) was employed to counteract this problem and resulted not only in enhanced fluorescence emission, but also allowed for elongated imaging and increased exposure times of the PMNC in a cellular environment. Conclusion Our experiments have demonstrated that β-ME visibly enhances the emission intensity. No deleterious effects to the cells were witnessed upon co-incubation with β-ME alone and no increases in background fluorescence were recorded. These results should present an interest for further development of in vitro biological imaging techniques.

  7. Black holes

    CERN Document Server

    Chrúsciel, P T

    2002-01-01

    This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usual one for gravity, and leads to the one associated with the Unruh metric in the case of Euler equations. We review the global conditions which have been used in the Scri-based definition of a black hole and point out the deficiencies of the Scri approach. Various results on the structure of horizons and apparent horizons are presented, and a new proof of semi-convexity of horizons based on a variational principle is given. Recent results on the classification of stationary singularity-free vacuum solutions are reviewed. ...

  8. Synergistic Activity of Deguelin and Fludarabine in Cells from Chronic Lymphocytic Leukemia Patients and in the New Zealand Black Murine Model

    Science.gov (United States)

    Rebolleda, Nerea; Losada-Fernandez, Ignacio; Perez-Chacon, Gema; Castejon, Raquel; Rosado, Silvia; Morado, Marta; Vallejo-Cremades, Maria Teresa; Martinez, Andrea; Vargas-Nuñez, Juan A.

    2016-01-01

    B-cell chronic lymphocytic leukemia (CLL) remains an incurable disease, and despite the improvement achieved by therapeutic regimes developed over the last years still a subset of patients face a rather poor prognosis and will eventually relapse and become refractory to therapy. The natural rotenoid deguelin has been shown to induce apoptosis in several cancer cells and cell lines, including primary human CLL cells, and to act as a chemopreventive agent in animal models of induced carcinogenesis. In this work, we show that deguelin induces apoptosis in vitro in primary human CLL cells and in CLL-like cells from the New Zealand Black (NZB) mouse strain. In both of them, deguelin dowregulates AKT, NFκB and several downstream antiapoptotic proteins (XIAP, cIAP, BCL2, BCL-XL and survivin), activating the mitochondrial pathway of apoptosis. Moreover, deguelin inhibits stromal cell-mediated c-Myc upregulation and resistance to fludarabine, increasing fludarabine induced DNA damage. We further show that deguelin has activity in vivo against NZB CLL-like cells in an experimental model of CLL in young NZB mice transplanted with spleen cells from aged NZB mice with lymphoproliferation. Moreover, the combination of deguelin and fludarabine in this model prolonged the survival of transplanted mice at doses of both compounds that were ineffective when administered individually. These results suggest deguelin could have potential for the treatment of human CLL. PMID:27101369

  9. A 6-year-long manipulation with soil warming and canopy nitrogen additions does not affect xylem phenology and cell production of mature black spruce

    Directory of Open Access Journals (Sweden)

    Madjelia Cangre Ebou eDAO

    2015-11-01

    Full Text Available The predicted climate warming and increased atmospheric inorganic nitrogen deposition are expected to have dramatic impacts on plant growth. However, the extent of these effects and their interactions remains unclear for boreal forest trees. The aim of this experiment was to investigate the effects of increased soil temperature and nitrogen (N depositions on stem intra-annual growth of two mature stands of black spruce [Picea mariana (Mill. BSP] in Quebec, Canada. During 2008-2013, the soil around mature trees was warmed up by 4 °C with heating cables during the growing season and precipitations containing three times the current inorganic N concentration were added by frequent canopy applications. Xylem phenology and cell production were monitored weekly from April to October. The 6-year-long experiment performed in two sites at different altitude showed no substantial effect of warming and N-depositions on xylem phenological phases of cell enlargement, wall thickening and lignification. Cell production, in terms of number of tracheids along the radius, also did not differ significantly and followed the same patterns in control and treated trees. These findings allowed the hypothesis of a medium-term effect of soil warming and N depositions on the growth of mature black spruce to be rejected.

  10. Chemical profiles of two pheromone glands are differentially regulated by distinct mating factors in honey bee queens (Apis mellifera L..

    Directory of Open Access Journals (Sweden)

    Elina L Niño

    Full Text Available Pheromones mediate social interactions among individuals in a wide variety of species, from yeast to mammals. In social insects such as honey bees, pheromone communication systems can be extraordinarily complex and serve to coordinate behaviors among many individuals. One of the primary mediators of social behavior and organization in honey bee colonies is queen pheromone, which is produced by multiple glands. The types and quantities of chemicals produced differ significantly between virgin and mated queens, and recent studies have suggested that, in newly mated queens, insemination volume or quantity can affect pheromone production. Here, we examine the long-term impact of different factors involved during queen insemination on the chemical composition of the mandibular and Dufour's glands, two of the major sources of queen pheromone. Our results demonstrate that carbon dioxide (an anesthetic used in instrumental insemination, physical manipulation of genital tract (presumably mimicking the act of copulation, insemination substance (saline vs. semen, and insemination volume (1 vs. 8 µl all have long-term effects on mandibular gland chemical profiles. In contrast, Dufour's gland chemical profiles were changed only upon insemination and were not influenced by exposure to carbon dioxide, manipulation, insemination substance or volume. These results suggest that the chemical contents of these two glands are regulated by different neuro-physiological mechanisms. Furthermore, workers responded differently to the different mandibular gland extracts in a choice assay. Although these studies must be validated in naturally mated queens of varying mating quality, our results suggest that while the chemical composition of Dufour's gland is associated with mating status, that of the mandibular glands is associated with both mating status and insemination success. Thus, the queen appears to be signaling both status and reproductive quality to the workers

  11. Honey Bee Colonies Headed by Hyperpolyandrous Queens Have Improved Brood Rearing Efficiency and Lower Infestation Rates of Parasitic Varroa Mites.

    Directory of Open Access Journals (Sweden)

    Keith S Delaplane

    Full Text Available A honey bee queen mates on wing with an average of 12 males and stores their sperm to produce progeny of mixed paternity. The degree of a queen's polyandry is positively associated with measures of her colony's fitness, and observed distributions of mating number are evolutionary optima balancing risks of mating flights against benefits to the colony. Effective mating numbers as high as 40 have been documented, begging the question of the upper bounds of this behavior that can be expected to confer colony benefit. In this study we used instrumental insemination to create three classes of queens with exaggerated range of polyandry--15, 30, or 60 drones. Colonies headed by queens inseminated with 30 or 60 drones produced more brood per bee and had a lower proportion of samples positive for Varroa destructor mites than colonies whose queens were inseminated with 15 drones, suggesting benefits of polyandry at rates higher than those normally obtaining in nature. Our results are consistent with two hypotheses that posit conditions that reward such high expressions of polyandry: (1 a queen may mate with many males in order to promote beneficial non-additive genetic interactions among subfamilies, and (2 a queen may mate with many males in order to capture a large number of rare alleles that regulate resistance to pathogens and parasites in a breeding population. Our results are unique for identifying the highest levels of polyandry yet detected that confer colony-level benefit and for showing a benefit of polyandry in particular toward the parasitic mite V. destructor.

  12. Variation in honey yield per hive of Africanized bees depending on the introducing time of young queens

    Directory of Open Access Journals (Sweden)

    Vladson Carbonari

    2016-05-01

    Full Text Available ABSTRACT: The objective of this research was to evaluate the honey production per hive and the egg laying rates of queens produced in 2007, 2008 and 2010. Thirty colonies initiated with a queen per colony at each climatic season were used during the three years. The years, started on January (summer, April (autumn, July (winter and October (spring and ended 12 months later, at the same periods related to each season of the later years. Honey supply were weighed before and after centrifugation to evaluate the quantity of the stored honey. Colonies with queens introduced during autumn and winter in the three years produced 57.2±6.0kg and 60.7±7.5kg of honey, respectively. In the first year of production activity, after the introduction of queens in the initial colonies, values were significantly higher than those obtained in colonies with queens introduced in the summer (39.3±7.6kg and spring (41.8±3.7kg. Egg laying rates of queens were higher in spring (98.2±3.9% and summer (88.4±7%, indicating greater food flow (flowerings in these seasons compared to the averages in autumn (30.3±8.1% and winter (24.5±7.2%. Produce and introduce queens of Africanized Apis mellifera in colonies initiated during autumn and winter was found to be economically feasible. Honey production of colonies initiated in these periods were higher and they had greater population stability in times of scarcity of flowerings.

  13. Black Hole Radiation and Volume Statistical Entropy

    CERN Document Server

    Rabinowitz, M

    2005-01-01

    The simplest possible equations for Hawking radiation, and other black hole radiated power is derived in terms of black hole density. Black hole density also leads to the simplest possible model of a gas of elementary constituents confined inside a gravitational bottle of Schwarzchild radius at tremendous pressure, which yields identically the same functional dependence as the traditional black hole entropy. Variations of Sbh are can be obtained which depend on the occupancy of phase space cells. A relation is derived between the constituent momenta and the black hole radius RH

  14. Enhanced photovoltaic performance of inverted pyramid-based nanostructured black-silicon solar cells passivated by an atomic-layer-deposited Al2O3 layer.

    Science.gov (United States)

    Chen, Hong-Yan; Lu, Hong-Liang; Ren, Qing-Hua; Zhang, Yuan; Yang, Xiao-Feng; Ding, Shi-Jin; Zhang, David Wei

    2015-10-07

    Inverted pyramid-based nanostructured black-silicon (BS) solar cells with an Al2O3 passivation layer grown by atomic layer deposition (ALD) have been demonstrated. A multi-scale textured BS surface combining silicon nanowires (SiNWs) and inverted pyramids was obtained for the first time by lithography and metal catalyzed wet etching. The reflectance of the as-prepared BS surface was about 2% lower than that of the more commonly reported upright pyramid-based SiNW BS surface over the whole of the visible light spectrum, which led to a 1.7 mA cm(-2) increase in short circuit current density. Moreover, the as-prepared solar cells were further passivated by an ALD-Al2O3 layer. The effect of annealing temperature on the photovoltaic performance of the solar cells was investigated. It was found that the values of all solar cell parameters including short circuit current, open circuit voltage, and fill factor exhibit a further increase under an optimized annealing temperature. Minority carrier lifetime measurements indicate that the enhanced cell performance is due to the improved passivation quality of the Al2O3 layer after thermal annealing treatments. By combining these two refinements, the optimized SiNW BS solar cells achieved a maximum conversion efficiency enhancement of 7.6% compared to the cells with an upright pyramid-based SiNWs surface and conventional SiNx passivation.

  15. Gene expression profiling in the ovary of Queen conch (Strombus gigas) exposed to environments with high tributyltin in the British Virgin Islands

    Energy Technology Data Exchange (ETDEWEB)

    Titley-O' Neal, Cassander P. [Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5 (Canada); Spade, Daniel J. [Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611 (United States); Zhang, Yanping [Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL 32611 (United States); Kan, Rosalinda; Martyniuk, Christopher J. [Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5 (Canada); Denslow, Nancy D. [Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611 (United States); MacDonald, Bruce A., E-mail: bmacdon@unbsj.ca [Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5 (Canada)

    2013-04-01

    Queen conch (Strombus gigas) are listed in CITES Appendix II. Populations may be declining due to anthropogenic inputs that include pollutants from boating activity. In the British Virgin Islands (BVI), some conch exhibit imposex, a condition in which male external genitalia are present in female conch. Previous studies suggest that tributyltin (TBT), an antifouling chemical used in boat paint, is correlated to increased incidence of imposex although the mechanisms leading to imposex are not known. The present study utilized a Queen conch microarray to measure the response of the ovarian transcriptome in conch inhabiting polluted environments with high TBT levels in the BVI. The polluted sites, Road Harbour (RH) and Trellis Bay (TB), are areas with high boating activity while the reference sites, Guana Island (GI) and Anegada (AN), are areas with low boating activity. There were 754 and 898 probes differentially expressed in the ovary of conch collected at RH and TB respectively compared to conch collected at GI. Of the genes that were differentially expressed at both sites, > 10% were shared suggesting that these sites have additional environmental factors influencing gene expression patterns. Functional enrichment analysis showed that the biological processes of cell proliferation, translation, and oxidative stress were over-represented in the polluted sites. Gene set enrichment analysis revealed that transcripts involved in the biological processes of general metabolism, immune, lipid metabolism, and stress were affected in conch from polluted environments. Interestingly, altered stress genes appeared to be more prevalent in conch collected from RH than TB, corresponding to the higher TBT load at RH compared to TB. Our study shows that stress pathways are affected in conch ovary in environments that experience heavy boating activity in the BVIs, although we are unable to directly link changes at the transcriptomics level to high TBT levels. Highlights:

  16. Mating frequencies of honey bee queens (Apis mellifera L. in a population of feral colonies in the Northeastern United States.

    Directory of Open Access Journals (Sweden)

    David R Tarpy

    Full Text Available Across their introduced range in North America, populations of feral honey bee (Apis mellifera L. colonies have supposedly declined in recent decades as a result of exotic parasites, most notably the ectoparasitic mite Varroa destructor. Nonetheless, recent studies have documented several wild populations of colonies that have persisted. The extreme polyandry of honey bee queens-and the increased intracolony genetic diversity it confers-has been attributed, in part, to improved disease resistance and may be a factor in the survival of these populations of feral colonies. We estimated the mating frequencies of queens in feral colonies in the Arnot Forest in New York State to determine if the level of polyandry of these queens is especially high and so might contribute to their survival success. We genotyped the worker offspring from 10 feral colonies in the Arnot Forest of upstate New York, as well as those from 20 managed colonies closest to this forest. We found no significant differences in mean mating frequency between the feral and managed queens, suggesting that queens in the remote, low-density population of colonies in the Arnot Forest are neither mate-limited nor adapted to mate at an especially high frequency. These findings support the hypothesis that the hyperpolyandry of honey bees has been shaped on an evolutionary timescale rather than on an ecological one.

  17. Males are here to stay: fertilization enhances viable egg production by clonal queens of the little fire ant ( Wasmannia auropunctata)

    Science.gov (United States)

    Miyakawa, Misato O.; Mikheyev, Alexander S.

    2015-04-01

    Evolution of reproduction strategies is affected by both phylogenetic and physiological constraints. Although clonality may benefit females, it may not be selected if a male contribution is necessary to start egg laying and embryo development. In little fire ant, Wasmannia auropunctata, sexual populations employ a typical Hymenopteran system of reproduction. In clonal populations, however, queens and males are produced with only maternal and paternal genomes, respectively, whereas sterile workers are produced sexually. Although this system requires both sexes for worker production, previous work has shown that workers may also be produced clonally by the queens. If so, why are males maintained in this species? Our data suggest that fertilization is necessary to increase the hatching rate of eggs. Although clonal queens can indeed produce both workers and queens without mating, the hatching rate is far below the level necessary to maintain functional colonies. On the other hand, virgin queens from populations exhibiting the original Hymenopteran reproduction system also show low hatching rates, but produce only haploid male eggs. Reasons for the existence of W. auropunctata males have been disputed. However, our data suggest that physiological constraints, such as the requirement for insemination, must be considered in regard to evolution of reproduction systems, in addition to ecological data and theoretical considerations of fitness.

  18. Sub-lethal effects of dietary neonicotinoid insecticide exposure on honey bee queen fecundity and colony development

    Science.gov (United States)

    Wu-Smart, Judy; Spivak, Marla

    2016-08-01

    Many factors can negatively affect honey bee (Apis mellifera L.) health including the pervasive use of systemic neonicotinoid insecticides. Through direct consumption of contaminated nectar and pollen from treated plants, neonicotinoids can affect foraging, learning, and memory in worker bees. Less well studied are the potential effects of neonicotinoids on queen bees, which may be exposed indirectly through trophallaxis, or food-sharing. To assess effects on queen productivity, small colonies of different sizes (1500, 3000, and 7000 bees) were fed imidacloprid (0, 10, 20, 50, and 100 ppb) in syrup for three weeks. We found adverse effects of imidacloprid on queens (egg-laying and locomotor activity), worker bees (foraging and hygienic activities), and colony development (brood production and pollen stores) in all treated colonies. Some effects were less evident as colony size increased, suggesting that larger colony populations may act as a buffer to pesticide exposure. This study is the first to show adverse effects of imidacloprid on queen bee fecundity and behavior and improves our understanding of how neonicotinoids may impair short-term colony functioning. These data indicate that risk-mitigation efforts should focus on reducing neonicotinoid exposure in the early spring when colonies are smallest and queens are most vulnerable to exposure.

  19. Sub-lethal effects of dietary neonicotinoid insecticide exposure on honey bee queen fecundity and colony development.

    Science.gov (United States)

    Wu-Smart, Judy; Spivak, Marla

    2016-08-26

    Many factors can negatively affect honey bee (Apis mellifera L.) health including the pervasive use of systemic neonicotinoid insecticides. Through direct consumption of contaminated nectar and pollen from treated plants, neonicotinoids can affect foraging, learning, and memory in worker bees. Less well studied are the potential effects of neonicotinoids on queen bees, which may be exposed indirectly through trophallaxis, or food-sharing. To assess effects on queen productivity, small colonies of different sizes (1500, 3000, and 7000 bees) were fed imidacloprid (0, 10, 20, 50, and 100 ppb) in syrup for three weeks. We found adverse effects of imidacloprid on queens (egg-laying and locomotor activity), worker bees (foraging and hygienic activities), and colony development (brood production and pollen stores) in all treated colonies. Some effects were less evident as colony size increased, suggesting that larger colony populations may act as a buffer to pesticide exposure. This study is the first to show adverse effects of imidacloprid on queen bee fecundity and behavior and improves our understanding of how neonicotinoids may impair short-term colony functioning. These data indicate that risk-mitigation efforts should focus on reducing neonicotinoid exposure in the early spring when colonies are smallest and queens are most vulnerable to exposure.

  20. Review of samples of sediment, tailings, and waters adjacent to the Cactus Queen gold mine, Kern County, California

    Science.gov (United States)

    Rytuba, James J.; Kim, Christopher S.; Goldstein, Daniel N.

    2011-01-01

    The Cactus Queen Mine is located in the western Mojave Desert in Kern County, California. The Cactus Queen gold-silver (Au-Ag) deposit is similar to other Au-Ag deposits hosted in Miocene volcanic rocks that consist of silicic domes and associated flows, pyroclastic rocks, and subvolcanic intrusions. The volcanic rocks were emplaced onto a basement of Mesozoic silicic intrusive rocks. A part of the Cactus Queen Mine is located on Federal land managed by the U.S. Bureau of Land Management (BLM). Staff from the BLM initially sampled the mine area and documented elevated concentrations of arsenic (As) in tailings and sediment. BLM then requested that the U.S. Geological Survey (USGS), in collaboration with Chapman University, measure and characterize As and other geochemical constituents in sediment, tailings, and waters on the part of the mine on Federal lands. This report is made in response to the request by the BLM, the lead agency mandated to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) - Removal Site Investigation (RSI). The RSI applies to the potential removal of As-contaminated mine waste from the Cactus Queen Mine as a means of reducing As release and exposure to humans and biota. This report summarizes data obtained from field sampling of sediments, mine tailings, and surface waters at the Cactus Queen Mine on January 27, 2008. Our results provide a preliminary assessment of the sources of As and associated chemical constituents that could potentially impact humans and biota.

  1. New mapping and structural constraints on the Queen Charlotte-Fairweather Fault system, southeast Alaska

    Science.gov (United States)

    Levoir, M. A.; Roland, E. C.; Gulick, S. P.; Haeussler, P. J.; Christeson, G. L.; Van Avendonk, H. J.

    2013-12-01

    The dextral Queen Charlotte-Fairweather Fault lies along the western margin of Canada and southeastern Alaska, a transform plate boundary accommodating motion between the North American and Pacific Plates. The Fairweather Fault is the northern extension of the Queen Charlotte Fault and has numerous and complex splays, including the Chichagof-Baranof Fault, the Peril Strait Fault, the Chatham Strait Fault, and the Icy Point-Lituya Bay Fault. Except for a few small areas, these fault systems have not been mapped in detail. We present updated geometries and fault maps of the entirety of the strike-slip system using seismic reflection and bathymetric data, including a 2004 seismic reflection survey (EW0408), 2005 United Nations Commission on Law of the Sea multibeam bathymetry, and legacy data from the U.S. Geological Survey (USGS) and the National Geophysical Data Center. This work is highly relevant for earthquake hazard research and mitigation in southeast Alaska. Several large (> Mw 7.0) earthquakes have occurred along this margin in the last century, impacting communities of southeastern Alaska and western Canada. Two large, recent events include 1) a Mw 7.7 earthquake that took place on 28 October 2012 near the Haida Gwaii Islands offshore of western Canada, and 2) a Mw 7.5 event which occurred on 05 January 2013, 330 km to the northwest and offshore of Craig, Alaska. Interestingly, the Haida Gwaii earthquake ruptured as a thrust event and the Craig earthquake ruptured with a near-vertical dextral strike-slip mechanism. Since a change in Pacific Plate motion around 4 million years ago, the southern Queen Charlotte Fault system has been obliquely converging at a rate of 20 mm/year, with the boundary accommodating about 80 km of perpendicular motion over that time. This convergence explains the Haida Gwaii thrust earthquake, but leaves questions about the along-strike fault structure. Two opposing end-member theories suggest convergence is accommodated by either: 1

  2. Piperine, an alkaloid from black pepper, inhibits growth of human colon cancer cells via G1 arrest and apoptosis triggered by endoplasmic reticulum stress.

    Science.gov (United States)

    Yaffe, Paul B; Power Coombs, Melanie R; Doucette, Carolyn D; Walsh, Mark; Hoskin, David W

    2015-10-01

    Piperine, a piperidine alkaloid present in black pepper, inhibits the growth of cancer cells, although the mechanism of action is not well understood. In this study, we show that piperine (75-150 µM) inhibited the growth of several colon cancer cell lines but had little effect on the growth of normal fibroblasts and epithelial cells. Piperine inhibited HT-29 colon carcinoma cell proliferation by causing G1 phase cell cycle arrest that was associated with decreased expression of cyclins D1 and D3 and their activating partner cyclin-dependent kinases 4 and 6, as well as reduced phosphorylation of the retinoblastoma protein and up-regulation of p21/WAF1 and p27/KIP1 expression. In addition, piperine caused hydroxyl radical production and apoptosis that was partially dependent on the production of reactive oxygen species. Piperine-treated HT-29 cells showed loss of mitochondrial membrane integrity and cleavage of poly (ADP-ribose) polymerase-1, as well as caspase activation and reduced apoptosis in the presence of the pan-caspase inhibitor zVAD-FMK. Increased expression of the endoplasmic reticulum stress-associated proteins inositol-requiring 1α protein, C/EBP homologous protein, and binding immunoglobulin protein, and activation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase, as well as decreased phosphorylation of Akt and reduced survivin expression were also observed in piperine-treated HT-29 cells. Furthermore, piperine inhibited colony formation by HT-29 cells, as well as the growth of HT-29 spheroids. Cell cycle arrest and endoplasmic reticulum stress-associated apoptosis following piperine treatment of HT-29 cells provides the first evidence that piperine may be useful in the treatment of colon cancer.

  3. When Power Seduces Women: Shakespeare’S Tragic (Mother Queens in Manga

    Directory of Open Access Journals (Sweden)

    Şerban Andreea

    2014-03-01

    Full Text Available Power is seductive, and fantasies of power affect both men and women, who are sometimes willing to do anything in order to achieve or retain it. The paper looks at how such a modern transmediation as manga renders powerful femininity in two of Shakespeare’s great tragedies, namely Hamlet and Macbeth. The paper aims to discuss the ways in which the emotive behaviour of both female protagonists eventually makes them inappropriate for the power roles they assume as wives, queens and mothers.

  4. Extreme queen-mating frequency and colony fission in African army ants

    DEFF Research Database (Denmark)

    Kronauer, Daniel J C; Schoning, Caspar; Pedersen, Jes S

    2004-01-01

    , which have so far been regarded as odd exceptions within the social Hymenoptera. Army ants and honeybees are fundamentally different in morphology and life history, but are the only social insects known that combine obligate multiple mating with reproduction by colony fission and extremely male......-mating frequencies reported so far for ants. This confirms that obligate multiple queen-mating in social insects is associated with large colony size and advanced social organization, but also raises several novel questions. First, these high estimates place army ants in the range of mating frequencies of honeybees...

  5. Fighting for a harem of queens: physiology of reproduction in Cardiocondyla male ants.

    Science.gov (United States)

    Heinze, J; Hölldobler, B

    1993-09-15

    Several species of the ant genus Cardiocondyla produce dimorphic males, which exhibit sharply different mating strategies. Winged males typically disperse to mate outside the nest, whereas wingless, ergatoid males stay in the nest and aggressively employ their mandibles against competing ergatoid males to monopolize the virgin queens eclosing in the nest. Such aggressive mating strategy would only be adaptive if the males had unlimited sperm supply. Histological studies showed that, contrary to the rule in the Hymenoptera order, the ergatoid Cardiocondyla males are indeed able to produce sperm during their entire adult life. Winged males, on the other hand, have only a limited sperm supply since spermatogenesis ceases in the late pupal stage.

  6. The Representation of the Queen of France: Marie Antoinette from the Eighteenth Century till Now

    Institute of Scientific and Technical Information of China (English)

    牛声爽

    2015-01-01

    As an iconic historical character, Marie Antoinette as the Queen was loved and hated by the French people. She experi-enced a period of great prosperity during a revolutionary time in France. In this paper, we are going to explore how Marie Antoi-nette was painted in the eighteenth century and study the power dynamic within her court life. However, the portrait art can only de-picts people on the outside, no matter how vivid the portrait painted. Sofia Coppola, the American film director, made a film which gives us a new impression of Marie Antoinette from the inside out.

  7. Drag queens' use of language and the performance of blurred gendered and racial identities.

    Science.gov (United States)

    Mann, Stephen L

    2011-01-01

    Building on Barrett (1998), this study provides a sociolinguistic analysis of the language used by Suzanne, a European-American drag queen, during her on-stage performance in the southeastern United States. Suzanne uses wigs and costumes to portray a female character on stage, but never hides the fact that she is biologically male. She is also a member of a predominantly African-American cast. Through her creative use of linguistic features such as stylemixing (i.e., the use of linguistic features shared across multiple language varieties) and expletives, Suzanne is able to perform an identity that frequently blurs gender and racial lines.

  8. The development of neurosurgery at the National Hospital for Neurology and Neurosurgery, Queen Square, London, England.

    Science.gov (United States)

    Powell, Michael; Kitchen, Neil

    2007-11-01

    The National Hospital for Neurology and Neurosurgery, Queen Square, London is one of the oldest clinical neuroscience hospitals in the world. It was formed from the fusion of itself with the Maida Vale Hospital in 1948. More recently, in 1996, it was incorporated into the University College London Hospitals group. It has had many distinguished neurosurgeons on its staff, whose history from Sir Victor Horsley to the present is described with particular reference to the development of the specialty of neurosurgery. The current neurosurgical staff and future developments of neurosurgery at the hospital are also elucidated.

  9. An Extensive Survey of the Phytochemistry and Therapeutic Potency of Ocimum sanctum (Queen of Herbs

    Directory of Open Access Journals (Sweden)

    *S. K. Bariyah

    2013-03-01

    Full Text Available Ocimum sanctum, known as Queen of Herbs, is an important member of the family Lamiaceae due to its use in herbal medication centuries back, especially, in India and other parts of the sub-continent. It is still a subject of immense importance in modern medical research and it is due to the chemical constituents present in it like flavonoids, terpenoids, alkaloids, saponins, vitamins, minerals, proteins, carbohydrates and many others. It has shown a wide range of therapeutic potencies like antimicrobial, anticataleptic, antitoxic, immunomodulatory, analgesic, antidiabetic and cardioprotective activities. The aim of the present review is to present an extensive survey on the phytochemistry and pharmacological applications of the herb.

  10. black cat

    Institute of Scientific and Technical Information of China (English)

    杜铁梅

    2016-01-01

    The black cat is a masterpiece of short fiction of Poe. He successfully solved the problem of creating of the horror effect by using scene description, symbol, repetition and first-person narrative methods. And created a complete and unified mysterious terror, achieved the effect of shocking. This paper aims to discuss the mystery in-depth and to enrich the research system in Poe’s novels.

  11. The differential anti-proliferation effect of white (Pueraria mirifica), red (Butea superba), and black (Mucuna collettii) Kwao Krua plants on the growth of MCF-7 cells.

    Science.gov (United States)

    Cherdshewasart, W; Cheewasopit, W; Picha, P

    2004-08-01

    The differential anti-proliferation effect of white (Pueraria mirifica), red (Butea superba) and black (Mucuna collettii) Kwao Krua plant extracts on the growth of MCF-7 cells was evaluated after 4 days of incubation. The percent cell growth comparison was based on protein determination of the harvested cells in parallel with the control group and Pueraria lobata treatment group. Pueraria lobata led to no proliferation and a mild anti-proliferation effect on the growth of MCF-7 cells. Pueraria mirifica caused proliferation at 1 microg/mL and an anti-proliferative effect on the growth of MCF-7 cells at 100 and 1000 microg/mL with an ED50 value of 642.83 microg/mL. Butea superba led to no proliferation and an anti-proliferation effect on the growth of MCF-7 cells at 10, 100 and 1000 microg/mL with an ED50 value of 370.91 microg/mL. Mucuna collettii led to no proliferation and an anti-proliferation effect on the growth of MCF-7 cells at 100 and 1000 microg/mL with an ED50 value of 85.36 microg/mL. The results demonstrated that only Pueraria mirifica showed an estrogenic effect on MCF-7 cell growth and a clear antagonistic effect with E2 at high concentration. Butea superba and Mucuna collettii exhibited only anti-proliferation effects on the growth of MCF-7 cells in relation with a possible anti-estrogen mechanism or a potent cytotoxic effect.

  12. Assessment of the cytotoxic, genotoxic and mutagenic effects of the commercial black dye in Allium cepa cells before and after bacterial biodegradation treatment.

    Science.gov (United States)

    Ventura-Camargo, Bruna de Campos; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

    2016-10-01

    The present study evaluated the cytotoxic, genotoxic and mutagenic actions of different concentrations (50 and 200 μg/L) of BDCP (Black Dye Commercial Product) used by textile industries, before and after bacterial biodegradation, by the conventional staining cytogenetic technique and NOR-banding in Allium cepa cells. Differences in the chromosomal and nuclear aberrations and alterations in the number of nucleoli were observed in cells exposed to BDCP with and without the microbial treatment. The significant frequencies of chromosome and nuclear aberrations noted in the tests with bacterially biodegraded BDCP indicate that the metabolites generated by degradation are more genotoxic than the chemical itself. Losses of genetic material characterize a type of alteration that was mainly associated with the action of the original BDCP, whereas chromosome stickiness, nuclear buds and binucleated cells were the aberrations that were preferentially induced by BDCP metabolites after biodegradation. The significant frequencies of cell death observed in the tests with biodegraded BDCP also show the cytotoxic effects of the BDCP metabolites. The reduction in the total frequency of altered cells after the recovery treatments showed that the test organism A. cepa has the ability to recover from damage induced by BDCP and its metabolites after the exposure conditions are normalized.

  13. Honey Bee Colonies Headed by Hyperpolyandrous Queens Have Improved Brood Rearing Efficiency and Lower Infestation Rates of Parasitic Varroa Mites

    Science.gov (United States)

    Delaplane, Keith S.; Pietravalle, Stéphane; Brown, Mike A.; Budge, Giles E.

    2015-01-01

    A honey bee queen mates on wing with an average of 12 males and stores their sperm to produce progeny of mixed paternity. The degree of a queen’s polyandry is positively associated with measures of her colony’s fitness, and observed distributions of mating number are evolutionary optima balancing risks of mating flights against benefits to the colony. Effective mating numbers as high as 40 have been documented, begging the question of the upper bounds of this behavior that can be expected to confer colony benefit. In this study we used instrumental insemination to create three classes of queens with exaggerated range of polyandry– 15, 30, or 60 drones. Colonies headed by queens inseminated with 30 or 60 drones produced more brood per bee and had a lower proportion of samples positive for Varroa destructor mites than colonies whose queens were inseminated with 15 drones, suggesting benefits of polyandry at rates higher than those normally obtaining in nature. Our results are consistent with two hypotheses that posit conditions that reward such high expressions of polyandry: (1) a queen may mate with many males in order to promote beneficial non-additive genetic interactions among subfamilies, and (2) a queen may mate with many males in order to capture a large number of rare alleles that regulate resistance to pathogens and parasites in a breeding population. Our results are unique for identifying the highest levels of polyandry yet detected that confer colony-level benefit and for showing a benefit of polyandry in particular toward the parasitic mite V. destructor. PMID:26691845

  14. In utero exposure to nanosized carbon black (Printex90) does not induce tandem repeat mutations in female murine germ cells

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner; Shipley, Thomas; Jackson, Petra

    2013-01-01

    J mice were exposed four times during gestation by intratracheal instillation of 67μg/animal of nanosized carbon black Printex90 or vehicle (gestation days 7, 10, 15 and 18). Female offspring were raised to maturity and mated with unexposed CBA males. Expanded simple tandem repeat (ESTR) germline...... mutation rates in the resulting F2 generation were determined from full pedigrees (mother, father, offspring) of F1 female mice (178 CB-exposed and 258 control F2 offspring). ESTR mutation rates in CB-exposed F2 female offspring were not statistically different from those of F2 female control offspring....

  15. Queen-worker caste ratio depends on colony size in the pharaoh ant (Monomorium pharaonis)

    DEFF Research Database (Denmark)

    Schmidt, Anna Mosegaard; Linksvayer, Timothy Arnold; Boomsma, Jacobus Jan

    2011-01-01

    The success of an ant colony depends on the simultaneous presence of reproducing queens and nonreproducing workers in a ratio that will maximize colony growth and reproduction. Despite its presumably crucial role, queen–worker caste ratios (the ratio of adult queens to workers) and the factors......, for the first time in a social insect, we confirmed the general life history prediction by Smith and Fretwell (Am Nat 108:499–506, 1974) that offspring number varies more than offspring size. Our findings document a high level of plasticity in energy allocation toward female castes and suggest that polygynous...

  16. Glycogen in honeybee queens, workers and drones (Apis mellifera carnica Pollm.).

    Science.gov (United States)

    Crailsheim, K; Panzenböck, U

    1997-02-21

    Honey bees (Apis mellifera carnica Pollm.) have low glycogen reserves in summer. Upon emergence drones have significantly larger amounts per unit weight when emerging, than workers; perhaps as adaption to the risk of not being fed as intensely as young workers. Maximum content was 0.23mg for workers (28d), and 0.59mg for drones (after emergence). Workers have relatively constant glycogen contents during their life, and very young drones have more glycogen than older ones. Young queens are similar to workers. In workers and queens in summer the greatest amounts of glycogen are found in the thorax. When the bees start flying (6th-8th day of life), drones have the highest amounts in the head (probably to supply their eyes), and upon maturity, drones have the least glycogen in the abdomen.Workers in winter show different glycogen values depending on whether they are active bees from the core area (0.23mg) or inactive ones from the outer surface of the winter cluster (0.37mg). They use glycogen from the thorax and the abdomen for their ongoing energy need.

  17. Drone exposure to the systemic insecticide Fipronil indirectly impairs queen reproductive potential

    Science.gov (United States)

    Kairo, Guillaume; Provost, Bertille; Tchamitchian, Sylvie; Ben Abdelkader, Faten; Bonnet, Marc; Cousin, Marianne; Sénéchal, Jacques; Benet, Pauline; Kretzschmar, André; Belzunces, Luc P.; Brunet, Jean-Luc

    2016-01-01

    A species that requires sexual reproduction but cannot reproduce is doomed to extinction. The important increasing loss of species emphasizes the ecological significance of elucidating the effects of environmental stressors, such as pesticides, on reproduction. Despite its special reproductive behavior, the honey bee was selected as a relevant and integrative environmental model because of its constant and diverse exposure to many stressors due to foraging activity. The widely used insecticide Fipronil, the use of which is controversial because of its adverse effects on honey bees, was chosen to expose captive drones in hives via syrup contaminated at 0.1 μg/L and gathered by foragers. Such environmental exposure led to decreased spermatozoa concentration and sperm viability coupled with an increased sperm metabolic rate, resulting in drone fertility impairment. Subsequently, unexposed queens inseminated with such sperm exhibited fewer spermatozoa with lower viability in their spermatheca, leaving no doubt about the detrimental consequences for the reproductive potential of queens, which are key for colony sustainability. These findings suggest that pesticides could contribute to declining honey bee populations through fertility impairment, as exemplified by Fipronil. More broadly, reproductive disorders should be taken into consideration when investigating the decline of other species. PMID:27549030

  18. Correlates of Queen Pineapple (AnanascomosusLinn Farming Practices in Camarines Norte, Philippines

    Directory of Open Access Journals (Sweden)

    Sonia S. Carbonell

    2015-12-01

    Full Text Available This study aimed to provide valuable information about the realities of the Queen pineapple (QP farmers in Camarines Norte, highlighting their farming practices and worldview about sustainable development. Most of the respondents are owner-operator having a mean farm size of 1.33 hectares devoted to queen pineapple farming and crop diversification with two to seven crops combined to augment income. Cropping pattern employed by most of the respondents is multiple cropping, specifically intercropping, rotational cropping, and fallowing. Soil nutrient and weed management of most respondents is conventional: inorganic fertilizers and chemical based, respectively. However, pest control management by most of the respondents is of the alternative method. Overall, QP farmer respondents were found to be practicing alternative farming methods. The problems cited by the respondents were mainly production, marketing and communication-related. The respondents showed that they have moved towards alternative farming. However, more attention should be given to soil nutrient and weed management practices. Strengthening communication-related activities, improved technology, and ensured availability of resources is necessary to have good avenue for change. These findings should make agencies concerned to promote alternative farming and sustainable agriculture. The significant attributes of the QP farmer respondents can be used as entry point for any development program to fully advocate alternative farming among the local people as a social movement.

  19. Drone exposure to the systemic insecticide Fipronil indirectly impairs queen reproductive potential.

    Science.gov (United States)

    Kairo, Guillaume; Provost, Bertille; Tchamitchian, Sylvie; Ben Abdelkader, Faten; Bonnet, Marc; Cousin, Marianne; Sénéchal, Jacques; Benet, Pauline; Kretzschmar, André; Belzunces, Luc P; Brunet, Jean-Luc

    2016-08-23

    A species that requires sexual reproduction but cannot reproduce is doomed to extinction. The important increasing loss of species emphasizes the ecological significance of elucidating the effects of environmental stressors, such as pesticides, on reproduction. Despite its special reproductive behavior, the honey bee was selected as a relevant and integrative environmental model because of its constant and diverse exposure to many stressors due to foraging activity. The widely used insecticide Fipronil, the use of which is controversial because of its adverse effects on honey bees, was chosen to expose captive drones in hives via syrup contaminated at 0.1 μg/L and gathered by foragers. Such environmental exposure led to decreased spermatozoa concentration and sperm viability coupled with an increased sperm metabolic rate, resulting in drone fertility impairment. Subsequently, unexposed queens inseminated with such sperm exhibited fewer spermatozoa with lower viability in their spermatheca, leaving no doubt about the detrimental consequences for the reproductive potential of queens, which are key for colony sustainability. These findings suggest that pesticides could contribute to declining honey bee populations through fertility impairment, as exemplified by Fipronil. More broadly, reproductive disorders should be taken into consideration when investigating the decline of other species.

  20. Tremors along the Queen Charlotte Margin triggered by large teleseismic earthquakes

    Science.gov (United States)

    Aiken, Chastity; Peng, Zhigang; Chao, Kevin

    2013-03-01

    We conduct a systematic search of tectonic tremors along the Queen Charlotte Margin (QCM) in western Canada triggered by distant earthquakes. We identify triggered tremor as non-impulsive, high-frequency signals coherent among several stations and coincident with passing surface waves. So far, the 2002 Mw7.9 Denali Fault, the 2004 Mw9.2 Sumatra, and the 2011 Mw9.1 Tohoku-Oki earthquakes have triggered clear tremor in this region. The 2010 Mw8.8 Maule, Chile and the 2012 Mw8.6 Sumatra earthquakes may have triggered, but tremors in these two cases did not meet all of our criteria. The triggered tremors are mostly located east of the Queen Charlotte Fault in the southern portion of Haida Gwaii, near the epicenter of the 28 October 2012 Mw7.7 earthquake. Similar to the observations in other regions, the triggered tremors were initiated by the Love waves and continued during the subsequent Rayleigh waves. Tremor bursts correlate with both the particle velocity and displacement of the Love waves, indicating they are triggered at either low-angle thrust or vertical strike-slip faults. In addition, we find that the triggering potential for the QCM is controlled by a combination of amplitude, period, and incident angles.

  1. The Red Queen in mitochondria: cyto-nuclear co-evolution, hybrid breakdown and human disease

    Directory of Open Access Journals (Sweden)

    Jui-Yu eChou

    2015-05-01

    Full Text Available Cyto-nuclear incompatibility, a specific form of Dobzhansky-Muller incompatibility caused by incompatible alleles between mitochondrial and nuclear genomes, has been suggested to play a critical role during speciation. Several features of the mitochondrial genome (mtDNA, including high mutation rate, dynamic genomic structure, and uniparental inheritance, make mtDNA more likely to accumulate mutations in the population. Once mtDNA has changed, the nuclear genome needs to play catch-up due to the intimate interactions between these two genomes. In two populations, if cyto-nuclear co-evolution is driven in different directions, it may eventually lead to hybrid incompatibility. Although cyto-nuclear incompatibility has been observed in a wide range of organisms, it remains unclear what type of mutations drives the co-evolution. Currently, evidence supporting adaptive mutations in mtDNA remains limited. On the other hand, it has been known that some mutations allow mtDNA to propagate more efficiently but compromise the host fitness (described as selfish mtDNA. Arms races between such selfish mtDNA and host nuclear genomes can accelerate cyto-nuclear co-evolution and lead to a phenomenon called the Red Queen Effect. Here, we discuss how the Red Queen Effect may contribute to the frequent observation of cyto-nuclear incompatibility and be the underlying driving force of some human mitochondrial diseases.

  2. Knights, knaves, pawns and queens: attitudes to behaviour in postwar Britain.

    Science.gov (United States)

    Welshman, John

    2007-02-01

    The choice agenda is currently one of the most prominent in public policy. One of its main architects, Julian Le Grand, has used the metaphors of knights, knaves, pawns and queens to characterise changing attitudes to questions of motivation and behaviour among public servants and service users. He has said, for example, that, in the immediate postwar period, public servants were perceived as public-spirited altruists (or knights), whereas service users were seen as passive (or pawns). It was only in the mid-1980s that public servants came to be seen as essentially self-interested (knaves) and service users came to be regarded as consumers (queens). However, this highly influential model has undergone remarkably little critical scrutiny to date. This article explores the debate over transmitted deprivation in the 1970s to provide a historically grounded piece of analysis to explore the accuracy and utility of these metaphors. It challenges Le Grand's arguments in three respects. Firstly, a concern with behaviour and agency went much broader than social security fraud. Secondly, the metaphor of pawns is inadequate for characterising attitudes towards the poor and service users. Finally, Le Grand's periodisation of the postwar era also has serious flaws.

  3. Drone exposure to the systemic insecticide Fipronil indirectly impairs queen reproductive potential

    Science.gov (United States)

    Kairo, Guillaume; Provost, Bertille; Tchamitchian, Sylvie; Ben Abdelkader, Faten; Bonnet, Marc; Cousin, Marianne; Sénéchal, Jacques; Benet, Pauline; Kretzschmar, André; Belzunces, Luc P.; Brunet, Jean-Luc

    2016-08-01

    A species that requires sexual reproduction but cannot reproduce is doomed to extinction. The important increasing loss of species emphasizes the ecological significance of elucidating the effects of environmental stressors, such as pesticides, on reproduction. Despite its special reproductive behavior, the honey bee was selected as a relevant and integrative environmental model because of its constant and diverse exposure to many stressors due to foraging activity. The widely used insecticide Fipronil, the use of which is controversial because of its adverse effects on honey bees, was chosen to expose captive drones in hives via syrup contaminated at 0.1 μg/L and gathered by foragers. Such environmental exposure led to decreased spermatozoa concentration and sperm viability coupled with an increased sperm metabolic rate, resulting in drone fertility impairment. Subsequently, unexposed queens inseminated with such sperm exhibited fewer spermatozoa with lower viability in their spermatheca, leaving no doubt about the detrimental consequences for the reproductive potential of queens, which are key for colony sustainability. These findings suggest that pesticides could contribute to declining honey bee populations through fertility impairment, as exemplified by Fipronil. More broadly, reproductive disorders should be taken into consideration when investigating the decline of other species.

  4. Molecular identification and transmission studies of X-cell parasites from Atlantic cod Gadus morhua (Gadiformes: Gadidae and the northern black flounder Pseudopleuronectes obscurus (Pleuronectiformes: Pleuronectidae

    Directory of Open Access Journals (Sweden)

    Watanabe K

    2011-02-01

    Full Text Available Abstract Background Epidermal pseudotumours from Hippoglossoides dubius and Acanthogobius flavimanus in Japan and gill lesions in Limanda limanda from the UK have been shown to be caused by phylogenetically related protozoan parasites, known collectively as X-cells. However, the phylogenetic position of the X-cell group is not well supported within any of the existing protozoan phyla and they are currently thought to be members of the Alveolata. Ultrastructural features of X-cells in fish pseudotumours are somewhat limited and no typical environmental stages, such as spores or flagellated cells, have been observed. The life cycles for these parasites have not been demonstrated and it remains unknown how transmission to a new host occurs. In the present study, pseudobranchial pseudotumours from Atlantic cod, Gadus morhua, in Iceland and epidermal pseudotumours from the northern black flounder, Pseudopleuronectes obscurus, in Japan were used in experimental transmission studies to establish whether direct transmission of the parasite is achievable. In addition, X-cells from Atlantic cod were sequenced to confirm whether they are phylogenetically related to other X-cells and epidermal pseudotumours from the northern black flounder were analysed to establish whether the same parasite is responsible for infecting different flatfish species in Japan. Results Phylogenetic analyses of small subunit ribosomal DNA (SSU rDNA sequence data from Atlantic cod X-cells show that they are a related parasite that occupies a basal position to the clade containing other X-cell parasites. The X-cell parasite causing epidermal pseudotumours in P. obscurus is the same parasite that causes pseudotumours in H. dubius. Direct, fish to fish, transmission of the X-cell parasites used in this study, via oral feeding or injection, was not achieved. Non-amoeboid X-cells are contained within discrete sac-like structures that are loosely attached to epidermal pseudotumours in

  5. The queen is not a pacemaker in the small-colony wasps Polistes instabilis and P. dominulus

    DEFF Research Database (Denmark)

    Jha, Shalene; Casey-Ford, Rowan G.; Pedersen, Jes Søe

    2006-01-01

    that suggest that two species of paper wasps do not fit this pattern. Polistes wasps are traditionally classified as primitively eusocial wasps, showing characteristics of simple insect societies, such as small colony sizes, lack of queen-worker dimorphism, and queen control of both reproduction and worker......How work is organized varies in social insect colonies. Some investigators have argued that the queen plays an active role in regulating worker activity in species with small, simple colonies, but that work is self-organized in species with large, complex colonies. Here, we present data...... the queen was removed did not differ significantly from activity levels in colonies with queens. Polistes instabilis and P. dominulus colonies showed characteristics of primitively eusocial insect societies, but also showed worker initiation of colony activity, suggesting that these two species represent...

  6. Ground-water and geohydrologic conditions in Queens County, Long Island, New York

    Science.gov (United States)

    Soren, Julian

    1971-01-01

    Queens County is a heavily populated borough of New York City, at the western end of Long Island, N. Y., in which large amounts of ground water are used, mostly for public supply. Ground water, pumped from local aquifers, by privately owned water-supply companies, supplied the water needs of about 750,000 of the nearly 2 million residents of the county in 1967; the balance was supplied by New York City from surface sources outside the county in upstate New York. The county's aquifers consist of sand and gravel of Late Cretaceous and of Pleistocene ages, and the aquifers comprise a wedge-shaped ground-water reservoir lying on a southeastward-sloping floor of Precambrian(?) bedrock. Beds of clay and silt generally confine water in the deeper parts of the reservoir; water in the deeper aquifers ranges from poorly confined to well confined. Wisconsin-age glacial deposits in the uppermost part of the reservoir contain ground water under water-table conditions. Ground water pumpage averaged about 60 mgd (million gallons per day) in Queens County from about 1900 to 1967. Much of the water was used in adjacent Kings County, another borough of New York City, prior to 1950. The large ground-water withdrawal has resulted in a wide-spread and still-growing cone of depression in the water table, reflecting a loss of about 61 billion gallons of fresh water from storage. Significant drawdown of the water table probably began with rapid urbanization of Queens County in the 1920's. The county has been extensively paved, and storm and sanitary sewers divert water, which formerly entered the ground, to tidewater north and south of the county. Natural recharge to the aquifers has been reduced to about one half of the preurban rate and is below the withdrawal rate. Ground-water levels have declined more than 40. feet from the earliest-known levels, in 1903, to 1967, and the water table is below sea level in much of the county. The aquifers are being contaminated by the movement of

  7. Black gold

    CERN Document Server

    Fletcher, MW

    2016-01-01

    Following the Yom Kippur war of October 1973, OPEC raises the price of oil by 70% along with a 5% reduction in oil production. Len Saunders a highly skilled and knowledgeable British engineer for Jaguar motors, is approached by the UK energy commission in the January of 1974 to create a new propulsion system; using a secret document from a German WW2 scientist, that they have come into possession of. Len Saunders sets to work on creating the holy grail of energy. Seven years later 1981, Haidar Farooq the Kuwait oil minister working at OPEC and head of a secret organisation named Black Gold bec

  8. Apoptosis induction in human leukemic cells by a novel protein Bengalin, isolated from Indian black scorpion venom: through mitochondrial pathway and inhibition of heat shock proteins.

    Science.gov (United States)

    Gupta, Shubho Das; Gomes, Antony; Debnath, Anindita; Saha, Archita; Gomes, Aparna

    2010-01-27

    Scorpion venom possesses protein toxins having numerous biological activities, some of which are potentially anticancerous. Previously we had reported antiproliferative activity of the venom of Indian black scorpion, Heterometrus bengalensis Koch. Here we have isolated and purified a novel protein named Bengalin (72kDa) from the venom, responsible for antiproliferative and apoptogenic activities against human leukemic cells U937 (histiocytic lymphoma) and K562 (chronic myelogenous leukemia). N-terminal sequence of first 20 amino acids of Bengalin was G-P-L-T-I-L-H-I-N-D-V-H-A-A/R-F-E-Q/G-F/G-N-T. Bengalin induced cell growth inhibition at IC(50) values of 3.7 and 4.1 microg/ml for U937 and K562 cells respectively did not significantly affect normal human lymphocytes. Inhibition of U937 and K562 cell proliferation occurred by apoptosis as evidenced from damaged nuclei, cell cycle arrest at sub G1 phase, increase of early apoptotic cells, augmentation of DNA fragmentation and also a reduction of telomerase activity. Further insights revealed that Bax:Bcl2 ratio was elevated after Bengalin treatment. Moreover Bengalin elicited loss of mitochondrial membrane potential (MMP) which commenced cytochrome c release in cytosol, decreased heat shock protein (HSP) 70 and 90 expression, activated caspase-9, caspase-3 and induced poly(ADP-ribose) polymerase (PARP) cleavage. We have also determined that HSP70 and 90 inhibitions correlated with Bengalin induced antiproliferation, caspase-3 upregulation, apoptogenesis and increased DNA fragmentation. These results hypothesize that Bengalin might provide a putative molecular mechanism for their anticancer effect on human leukemic cells which might be mediated by mitochondrial death cascade. Inhibition of HSPs might also play a crucial role in induction of apoptosis.

  9. Increased oxidative stress and decreased activities of Ca2+/Mg2+-ATPase and Na+/K+-ATPase in the red blood cells of the hibernating black bear

    Science.gov (United States)

    Chauhan, V.P.S.; Tsiouris, J.A.; Chauhan, A.; Sheikh, A.M.; Brown, W. Ted; Vaughan, M.

    2002-01-01

    During hibernation, animals undergo metabolic changes that result in reduced utilization of glucose and oxygen. Fat is known to be the preferential source of energy for hibernating animals. Malonyldialdehyde (MDA) is an end product of fatty acid oxidation, and is generally used as an index of lipid peroxidation. We report here that peroxidation of lipids is increased in the plasma and in the membranes of red blood cells in black bears during hibernation. The plasma MDA content was about four fold higher during hibernation as compared to that during the active, non-hibernating state (P increased during hibernation (P increased oxidative stress, and have reduced activities of membrane-bound enzymes such as Ca2+/Mg2+-ATPase and Na+/K+-ATPase. These changes can be considered part of the adaptive for survival process of metabolic depression. ?? 2002 Elsevier Science Inc. All rights reserved.

  10. Ser e estar drag queen: um estudo sobre a configuração da identidade queer Being a drag queen: a study on the characterization of the queer identity

    Directory of Open Access Journals (Sweden)

    Maria Teresa Vargas Chidiac

    2004-12-01

    Full Text Available O principal objetivo deste estudo foi identificar o processo de formação da identidade queer das drag queens do circuito Balneário Camboriú e Florianópolis. Para atingir este propósito, foi investigado como se processa a relação de identificação das drag queens com o gênero feminino e masculino. Abordou-se também de que modo configura-se a relação entre o sujeito e a personagem drag queen, descrevendo a sua visão sobre a própria sexualidade. Estes dados foram obtidos através de pesquisa exploratória com três sujeitos através de entrevistas, sendo o roteiro semidirigido, além de terem sido realizadas visitas em suas moradias e em casas noturnas onde faziam apresentações artísticas. Os entrevistados relataram que a identidade das drags se diferencia de suas identidades pessoais em diversos aspectos. A drag possui características físicas e psicológicas, além de posturas e atitudes, que são próprias da personagem e que a distinguem do sujeito que a compõe. Mas houve relatos com freqüência que existem situações em que personagem e sujeito que a compõe se confundem. Através dos resultados, pode-se identificar como a configuração da identidade está relacionada com a socialização e com as transformações do corpo. Os sujeitos que interpretam as drag queens manifestam esse jogo de identidades, de ambos os gêneros, configurando o que pode se identificar com uma identidade queer.The main objective of this study was to identify the formation process of queer identity of some drag queens in the cities of Balneário Camboriú and Florianópolis, in the state of Santa Catarina, south of Brazil. In order to achieve this objective, we investigated how the drag queens identify themselves with the female and male genders. In addition, we investigated how the relation between the interviewed subjects and their drag queen character gets established through their description of their own sexuality. The data was collected

  11. 蜜蜂黑色王台病毒SYBR Green Ⅰ RT-qPCR检测方法的建立%A Real-time Quantitative RT-PCR Assay for the Detection of Black Queen-Cell Virus in Honeybee

    Institute of Scientific and Technical Information of China (English)

    李月龙; 周丹银; 赵文正; 冯毅楠; 和绍禹; 尹革芬

    2016-01-01

    为建立蜜蜂黑色王台病毒RT-qPCR检测方法,以蜜蜂黑色王台病毒(BQCV)衣壳蛋白基因部分序列作为目的基因,构建标准质粒并作为模板,建立标准曲线,且对所建立方法的灵敏度和特异性进行分析.结果表明:所建立的RT-qPCR检测方法,扩增效率E=108%,可信度R2=0.997.该方法灵敏度高,最低检出量为101个拷贝;该方法特异性强,仅能检出BQCV,而不能检测出蜜蜂囊状幼虫病毒、畸翅病毒.以上结果表明已成功建立了针对BQCV灵敏、特异的RT-qPCR检测方法.

  12. Assessing the Cytotoxicity of Black Carbon As A Model for Ultrafine Anthropogenic Aerosol Across Human and Murine Cells: A Chronic Exposure Model of Nanosized Particulate Matter

    Science.gov (United States)

    Salinas, E.

    2015-12-01

    Combustion-derived nanomaterials or ultrafine (Juarez, Chihuahua, Mexico, comprising the Paso del Norte air basin. A study conducted by scientists from the Research Triangle Park in North Carolina, analyzed sites adjacent to heavy-traffic highways in El Paso and elucidated higher UFP concentrations in comparison to previously published work exploring pollution and adverse health effects in the basin. UFPs can penetrate deep into the alveolar sacs of the lung, reaching distant alveolar sacs and inducing a series of immune responses that are detrimental to the body: evidence suggests that UFPs can also cross the alveolar-blood barrier and potentially endanger the body's immune response. The physical properties of UFPs and the dynamics of local atmospheric and topographical conditions indicate that emissions of nanosized carbonaceous aerosols could pose significant threats to biological tissues upon inhalation by local residents of the Paso del Norte. This study utilizes Black Carbon (BC) as a model for environmental UFPs and its effects on the immunological response. An in vitro approach is used to measure the ability of BC to promote cell death upon long-term exposure. Human epithelial lung cells (A549), human peripheral-blood monocytes (THP-1), murine macrophages (RAW264.7), and murine epithelial lung cells (LA-4) were treated with BC and assessed for metabolic activity after chronic exposure utilizing three distinct and independent cell viability assays. The cell viability experiments included a chronic study at 7, 10, and 14 days of UFP exposure at six different concentrations of BC: 100μM, 300μM, 600μM, 1,250μM, 2,500μM, and 5,000μM conducting the Trypan Blue (TB) Exclusion Assay, Calcein-AM Viability Assay, and CellTiter-Glo Viability Assay.

  13. Non-Detriment Finding Regarding the Export of Queen conch (Lobatus gigas) from St Eustatius (Caribbean Netherlands)

    NARCIS (Netherlands)

    Graaf, de M.; Meijer zu Schlochteren, M.; Boman, E.

    2014-01-01

    Queen conch (Lobatus gigas (Strombidae; Gastropoda) is a large, long-lived marine gastropod that is widely distributed throughout the coastal zones of the Wider Caribbean region. Because of concern for its future the species was listed in Appendix II of the Convention on International Trade in Endan

  14. Parthenogenetic flatworms have more symbionts than their coexisting, sexual conspecifics, but does this support the Red Queen?

    NARCIS (Netherlands)

    Michiels, N.K.; Beukeboom, L.W.; Pongratz, N.; Zeitlinger, J.

    2001-01-01

    The Red Queen hypothesis predicts that sexuality is favoured when virulent parasites adapt quickly to host genotypes. We studied a population of the flatworm Schmidtea polychroa in which obligate sexual and parthenogenetic individuals coexist. Infection rates by an amoeboid protozoan were consistent

  15. Morphometric study of newly emerged unmated queens of honey bee Apis mellifera L. in Ismailia Governorate, Egypt

    Directory of Open Access Journals (Sweden)

    S.M. Kamel

    2013-06-01

    Full Text Available Recently, morphometric analysis is being a very good tool for identification of honey bee races and characterization of genetic materials. This fact has motivated the present work to investigate the effects of two grafting methods, three types of artificial queen wax cups and four periods of queen rearing on some morphological characters of newly emerged queens. The developed technique used in the present study depends on the integration between Scanner unit and Photoshop program, called Scan Photo Method (SPM. The measurements of 23 morphological characteristics of reared queens were estimated by using SPM. Results indicated significant differences between periods in the measurements of the studied characteristics on forewing such as cubital index, distance C, distance D, radial field, inner wing length, inner wing width, dumb bell index, distance I, II, III and IV, except cubital A and cubital B. Regarding the effects of cup types and grafting methods, data also revealed significant differences in all measurements of studied characteristics, except tibial length, hind wing length, cubital B, radial field and distance IV. Further works in this area were recommended to find out a relation between some morphometric characters and important of some quantitative characters.

  16. Queen survival and oxalic acid residues in sugar stores after summer application against Varroa destructor in honey bees (Apis mellifera)

    NARCIS (Netherlands)

    Cornelissen, B.; Donders, J.N.L.C.; Stratum, van P.; Blacquière, T.; Dooremalen, van C.

    2012-01-01

    Methods using oxalic acid (OA) to control Varroa destructor in honey bee (Apis mellifera) colonies are widely applied. In this study, the effects of an OA spray application in early summer on the survival of young and old queens, and on OA residues in sugar stores were investigated. A questionnaire

  17. Screening anti-southern rice black-streaked dwarf virus drugs based on S7-1 gene expression in rice suspension cells.

    Science.gov (United States)

    Yu, Dandan; Wang, Zhenchao; Liu, Jing; Lv, Mingming; Liu, Jiaju; Li, Xiangyang; Chen, Zhuo; Jin, Linghong; Hu, Deyu; Yang, Song; Song, Baoan

    2013-08-28

    Southern rice black-streaked dwarf virus (SRBSDV) is a rice pathogen that had an outbreak in southern China in 2010 and caused significant crop losses. Therefore, screening for effective antiviral drugs against SRBSDV is very important. This study used rice suspension cells infected with SRBSDV by polyethylene glycol-mediated uptake for screening antiviral drugs. SRBSDV P7-1, which is coded by the S7-1 gene, has an intrinsic ability to self-interact to form tubules that play an important role in viral infection. Therefore, relative expression level of the SRBSDV S7-1 gene in infected rice suspension cells was assayed by real-time quantitative polymerase chain reaction to evaluate the antiviral activities of various drugs. Dufulin displayed the highest inhibitory activity against SRBSDV S7-1 expression. In addition, changes in peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) activities were determined in inoculated and noninoculated cells. The results showed that both POD and PPO activities increased upon dufulin treatment. Furthermore, the validity of this approach was confirmed in an in vivo experiment in which dufulin was found to effectively inhibit SRBSDV.

  18. Efficiency Enhancement of Nanotextured Black Silicon Solar Cells Using Al2O3/TiO2 Dual-Layer Passivation Stack Prepared by Atomic Layer Deposition.

    Science.gov (United States)

    Wang, Wei-Cheng; Tsai, Meng-Chen; Yang, Jason; Hsu, Chuck; Chen, Miin-Jang

    2015-05-20

    In this study, efficient nanotextured black silicon (NBSi) solar cells composed of silicon nanowire arrays and an Al2O3/TiO2 dual-layer passivation stack on the n(+) emitter were fabricated. The highly conformal Al2O3 and TiO2 surface passivation layers were deposited on the high-aspect-ratio surface of the NBSi wafers using atomic layer deposition. Instead of the single Al2O3 passivation layer with a negative oxide charge density, the Al2O3/TiO2 dual-layer passivation stack treated with forming gas annealing provides a high positive oxide charge density and a low interfacial state density, which are essential for the effective field-effect and chemical passivation of the n(+) emitter. In addition, the Al2O3/TiO2 dual-layer passivation stack suppresses the total reflectance over a broad range of wavelengths (400-1000 nm). Therefore, with the Al2O3/TiO2 dual-layer passivation stack, the short-circuit current density and efficiency of the NBSi solar cell were increased by 11% and 20%, respectively. In conclusion, a high efficiency of 18.5% was achieved with the NBSi solar cells by using the n(+)-emitter/p-base structure passivated with the Al2O3/TiO2 stack.

  19. Black Urine

    Directory of Open Access Journals (Sweden)

    Rahim Vakili

    2016-06-01

    Full Text Available A 2-year-old boy was born at term of healthy, non-consanguineous Iranian parents. His mother attended in the clinic with the history of sometimes discoloration of diapers after passing urine. She noticed that first at the age of one month with intensified in recent months. His Physical examination and growth parameters were normal. His mother denied taking any medication (sorbitol, nitrofurantoin, metronidazole, methocarbamol, sena and methyldopa (5. Qualitative urine examination showed dark black discoloration. By this history, alkaptonuria was the most clinical suspicious. A 24-hour-urine sample was collected and sent for quantitative measurements. The urine sample was highly positive for homogentisic acid and negative for porphyrin metabolites.

  20. Chronic exposure of imidacloprid and clothianidin reduce queen survival, foraging, and nectar storing in colonies of Bombus impatiens.

    Science.gov (United States)

    Scholer, Jamison; Krischik, Vera

    2014-01-01

    In an 11-week greenhouse study, caged queenright colonies of Bombus impatiens Cresson, were fed treatments of 0 (0 ppb actual residue I, imidacloprid; C, clothianidin), 10 (14 I, 9 C), 20 (16 I, 17C), 50 (71 I, 39 C) and 100 (127 I, 76 C) ppb imidacloprid or clothianidin in sugar syrup (50%). These treatments overlapped the residue levels found in pollen and nectar of many crops and landscape plants, which have higher residue levels than seed-treated crops (less than 10 ppb, corn, canola and sunflower). At 6 weeks, queen mortality was significantly higher in 50 ppb and 100 ppb and by 11 weeks in 20 ppb-100 ppb neonicotinyl-treated colonies. The largest impact for both neonicotinyls starting at 20 (16 I, 17 C) ppb was the statistically significant reduction in queen survival (37% I, 56% C) ppb, worker movement, colony consumption, and colony weight compared to 0 ppb treatments. Bees at feeders flew back to the nest box so it appears that only a few workers were collecting syrup in the flight box and returning the syrup to the nest. The majority of the workers sat immobilized for weeks on the floor of the flight box without moving to fed at sugar syrup feeders. Neonicotinyl residues were lower in wax pots in the nest than in the sugar syrup that was provided. At 10 (14) ppb I and 50 (39) ppb C, fewer males were produced by the workers, but queens continued to invest in queen production which was similar among treatments. Feeding on imidacloprid and clothianidin can cause changes in behavior (reduced worker movement, consumption, wax pot production, and nectar storage) that result in detrimental effects on colonies (queen survival and colony weight). Wild bumblebees depending on foraging workers can be negatively impacted by chronic neonicotinyl exposure at 20 ppb.

  1. Chronic exposure of imidacloprid and clothianidin reduce queen survival, foraging, and nectar storing in colonies of Bombus impatiens.

    Directory of Open Access Journals (Sweden)

    Jamison Scholer

    Full Text Available In an 11-week greenhouse study, caged queenright colonies of Bombus impatiens Cresson, were fed treatments of 0 (0 ppb actual residue I, imidacloprid; C, clothianidin, 10 (14 I, 9 C, 20 (16 I, 17C, 50 (71 I, 39 C and 100 (127 I, 76 C ppb imidacloprid or clothianidin in sugar syrup (50%. These treatments overlapped the residue levels found in pollen and nectar of many crops and landscape plants, which have higher residue levels than seed-treated crops (less than 10 ppb, corn, canola and sunflower. At 6 weeks, queen mortality was significantly higher in 50 ppb and 100 ppb and by 11 weeks in 20 ppb-100 ppb neonicotinyl-treated colonies. The largest impact for both neonicotinyls starting at 20 (16 I, 17 C ppb was the statistically significant reduction in queen survival (37% I, 56% C ppb, worker movement, colony consumption, and colony weight compared to 0 ppb treatments. Bees at feeders flew back to the nest box so it appears that only a few workers were collecting syrup in the flight box and returning the syrup to the nest. The majority of the workers sat immobilized for weeks on the floor of the flight box without moving to fed at sugar syrup feeders. Neonicotinyl residues were lower in wax pots in the nest than in the sugar syrup that was provided. At 10 (14 ppb I and 50 (39 ppb C, fewer males were produced by the workers, but queens continued to invest in queen production which was similar among treatments. Feeding on imidacloprid and clothianidin can cause changes in behavior (reduced worker movement, consumption, wax pot production, and nectar storage that result in detrimental effects on colonies (queen survival and colony weight. Wild bumblebees depending on foraging workers can be negatively impacted by chronic neonicotinyl exposure at 20 ppb.

  2. Natural Larval Diet Differently Influences the Pattern of Developmental Changes in DNA 5-Methylcytosine Levels in Apis mellifera Queens as Compared with Workers and Drones.

    Science.gov (United States)

    Strachecka, A; Olszewski, K; Bajda, M; Demetraki-Paleolog, J

    2015-08-01

    The principal mechanism of gene activation/silencing is DNA 5-methylcytosine methylation. This study was aimed at determining global DNA methylation levels in larvae, prepupae, pupae, and 1-day-old adults of Apis mellifera queens, workers and drones. The Imprint Methylated DNA Quantification Kit MDQ1 was used. Percentages of DNA 5-methylcytosine were low and relatively similar in the larvae of all the castes until 4th day of larval development (3-5%). However, they were higher in the drone and worker larvae than in the queen larvae. Generally, the developmental patterns of changes in the DNA methylation levels were different in the queens in comparison with the drones and workers. While methylation increased in the queens, it decreased in the drones and workers. Methylated DNA methylcytosine percentages and weights in the queen prepupae (15%, 9.18 ng) and pupae (21%, 10.74 ng) were, respectively, three and four times higher than in the worker/drone brood of the same age (2.5-4%, 0.03-0.07 ng). Only in the queens, after a substantial increase, did DNA methylation decrease almost twice between the pupal stage and queen emergence (from 21% and 10.74 ng to 12% and 6.78 ng). This finding seems very interesting, particularly for experimental gerontology.

  3. Provenance Constraints on the Mesozoic-Cenozoic Tectonic Evolution of the Queen Charlotte Islands Region

    Science.gov (United States)

    Mahoney, J.; Haggart, J. W.; Kimbrough, D.; Grove, M.

    2007-05-01

    The medial Cretaceous magmatic arc system of western North America was flanked by a series of forearc basins extending from Mexico to Alaska. Cretaceous strata in the Queen Charlotte Islands of northwest British Columbia are unique in this series of basins, as these strata have been displaced from the arc system by formation of the extensional Queen Charlotte basin in Cenozoic time. This displacement complicates reconstruction of the forearc basin, and makes it difficult to evaluate the controls on basin evolution. Sedimentologic, paleontologic, and detrital zircon analyses of forearc strata represented by the Valanginian- Campanian Queen Charlotte Group (QCG) constrain basin evolution and provide a framework for an interpretation of the Mesozoic-Cenozoic tectonic evolution of the Queen Charlotte Islands region. Basin subsidence initiated in Valanginian time with a marine transgression over irregular topography consisting of extensional fault blocks of pre-Cretaceous strata. Locally derived conglomerates at the base of the Longarm Formation are overlain by shallow marine shelf deposits that represent a westward-deepening, fining-upward transgressive succession with an eastern depositional edge that migrated eastward during Valanginian to Aptian time. West-directed paleocurrents and a unimodal detrital zircon population of 120-175 Ma grains provide the first linkage between the Cretaceous QCG and unroofed Jura-Cretaceous plutons of the Coast Plutonic Complex to the east. This initial transgressive sequence is superseded by a second pulse of clastic detritus in early Albian time, characterized by an easterly-derived, fossiliferous shallow-shelf sandstone (Haida Formation), fine-grained, outer shelf to upper slope strata (Bearskin Bay Formation), and mass-sediment gravity flows (Skidegate Formation). The unimodal zircon population (ca 140-175 Ma) in the lower Haida Formation is interpreted to reflect renewed uplift of Jura-Cretaceous arc plutons by contractional

  4. Stress fields of the San Andreas and Queen Charlotte transform faults

    Science.gov (United States)

    Kilty, Kevin T.

    1981-08-01

    Analytic solutions to the stress fields resulting from the San Andreas and Queen Charlotte transform faults may be found by applying conformal mappings to the generalized plane stress solution of stresses in a half-plane. The mean stress fields (one-half the trace of the stress tensor) found in this manner show a similarity to the deformation found in western Canada and the western United States. The results refute the hypothesis that Alaska acts as a continental buttress against deformation of the Canadian Cordillera. Moreover, these results imply that the differences in the tectonics of major transform boundaries are caused primarily by differences in lithospheric structure and differences in stress distribution along the plate boundaries.

  5. Cyber against punk: Greg Bear’s Queen of Angels as metamorphosed cyberpunk

    Directory of Open Access Journals (Sweden)

    M. F. Blatchford

    1994-05-01

    Full Text Available Recent American science fiction (which commercially dominates world science fiction incorporates two schools of thought, ‘cyberpunk' and ‘hard SF’. which may be read to embody, respectively, radical/liberal and patriotic/ conservative propaganda. This article, after attempting to define aspects of these schools, examines Queen of Angels by Greg Bear (who before producing that text had been a proponent of hard SF. This text is shown to have strong elements of cyberpunk (possibly, to judge by one critical review, appealing to a cyberpunk audience but to have transformed and inverted the radical and liberal themes of cyberpunk into conservative themes. The text thus illuminates philosophical and technical differences between the schools. It is suggested that the imagery of cyberpunk, and perhaps that of science fiction in general, is liable to such reversals of ideological significance.

  6. Enhancing the Simulation of Membrane System on the GPU for the N-Queens Problem

    Institute of Scientific and Technical Information of China (English)

    Ravie Chandren Muniyandi; Ali Maroosi

    2015-01-01

    Previous approaches using active mem-brane systems to solve the N-queens problem defined many membranes with just one rule inside them. This resulted in many communication rules utilised to communicate be-tween membranes, which made communications between the cores and the threads a very time-consuming process. The proposed approach reduces unnecessary membranes and communication rules by defining two membranes with many ob jects and rules inside each membrane. With this structure, ob jects and rules can evolve concurrently in par-allel, which makes the model suitable for implementation on a Graphics processing unit (GPU). The speedup using a GPU with global memory for N=10 is 10.6 times, but using tiling and shared memory, it is 33 times.

  7. Haida Gwaii / Queen Charlotte Islands demonstration tidal power plant feasibility study : summary results

    Energy Technology Data Exchange (ETDEWEB)

    Tu, A. [BC Hydro, Burnaby, BC (Canada)

    2008-07-01

    Remote communities may benefit from using tidal energy in terms of reduced diesel fuel consumption and the associated greenhouse gas emissions. A study was conducted to assess the feasibility for a tidal demonstration project on the Haida Gwaii, Queen Charlotte Islands. Candidate communities were scanned for resource potential, load profile, infrastructure distribution and community interest. This presentation focused on choosing an appropriate site for a given tidal power technology. Three hotspots in Masset Sound were identified as well as one hotspot at Juskatla Narrows. Technology providers were solicited for information on unit performance, cost, and trials to date. The presentation noted that demonstration or future commercial deployment is limited by resource and by the ability of the grid to accommodate tidal power. The presentation concluded with next steps which include publishing the study. tabs., figs.

  8. Society News: Queen honours Fellows; The Society and legacies; Thesis prizes; Lectures on laptops; Stonehenge story

    Science.gov (United States)

    2007-08-01

    The Queen's Birthday Honours list announced on 16 June contained some familiar names from astronomy. Prof. Mark Bailey (1) of Armagh Observatory, currently a Vice-President of the RAS, was awarded an MBE and Dr Heather Couper (2), former President of the British Astronomical Association, a CBE. Prof. Nigel Mason (3) of the Open University and inaugural Director of the Milton Keynes Science Festival received an OBE. Prof. Jocelyn Bell-Burnell (4), President of the RAS from 2002-2004, was awarded a DBE - and an Honorary Doctorate from Harvard University. In addition, Prof. Lord Rees (5), Astronomer Royal, president of the Royal Society and President of the RAS from 1992-1994, was appointed to the Order of Merit.

  9. Volunteering as Red Queen Mechanism for Cooperation in Public Goods Games

    Science.gov (United States)

    Hauert, Christoph; De Monte, Silvia; Hofbauer, Josef; Sigmund, Karl

    2002-05-01

    The evolution of cooperation among nonrelated individuals is one of the fundamental problems in biology and social sciences. Reciprocal altruism fails to provide a solution if interactions are not repeated often enough or groups are too large. Punishment and reward can be very effective but require that defectors can be traced and identified. Here we present a simple but effective mechanism operating under full anonymity. Optional participation can foil exploiters and overcome the social dilemma. In voluntary public goods interactions, cooperators and defectors will coexist. We show that this result holds under very diverse assumptions on population structure and adaptation mechanisms, leading usually not to an equilibrium but to an unending cycle of adjustments (a Red Queen type of evolution). Thus, voluntary participation offers an escape hatch out of some social traps. Cooperation can subsist in sizable groups even if interactions are not repeated, defectors remain anonymous, players have no memory, and assortment is purely random.

  10. Image and Role of the Queen Mother of the West in Han Grave Art

    Directory of Open Access Journals (Sweden)

    Nataša VAMPELJ SUHADOLNIK

    2015-12-01

    Full Text Available The present article is a detailed study of the image of an ancient Chinese goddess, The Queen Mother of the West, called Xiwangmu 西王母 in Chinese. In the mythological tradition, Xiwangmu is a goddess who possesses the elixir of immortality and dwells in the western paradise, on the magic mountain Kunlun 崑崙. While her image can be found in mural paintings, and on lacquered objects and bronze mirrors, it appears primarily in the form of relief images on the stones and bricks of grave chambers and temples in the Han (206 BCE–220 CE grave complexes. The literary tradition reveals a multifunctional role of the mother, with her many attributes developing in accordance with the changing values of social and mythological concepts. The article concludes with a detailed discussion of her image and role within the wider cosmological context of Han grave art.

  11. Honey bee males and queens use glandular secretions to enhance sperm viability before and after storage

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Boomsma, Jacobus Jan; Baer, Boris

    2009-01-01

    Internal fertilization requires live sperm to be transferred from male to female before egg fertilization. Both males and females assist the insemination process by providing sperm with glandular secretions, which have been inferred to contain subsets of proteins that maintain sperm viability. Here...... we show that in the honeybee (Apis mellifera) secretions of the male accessory glands, the major contributors towards seminal fluid, enhance sperm survival. We further demonstrate that the protein fraction of the male accessory gland secretion is indeed important for achieving the maximal effect...... on sperm survival. After sperm storage, the queens also provide sperm with secretions from spermathecal glands and we show that these secretions have a comparable positive effect on sperm viability. SDS gels show that the proteomic profiles of accessory gland secretion and spermathecal fluid secretion...

  12. THE LEGEND ABOUT THE QUEEN OF KANIS:A HISTORlCAL SOURCE?

    Institute of Scientific and Technical Information of China (English)

    LiliaBayun

    1994-01-01

    In 1970, during the excavations in the area of the Great Temple of Boghazkǒy (the Lower City) a cuneiform tablet was found that at once attracted the attention of Hittitologists. This tablet (Bo 70/10, KBo XXII 2) is the Old Hittite original, written in the old ductus, of KBo III 38 (=2 BoTU 13). The latter, known from the autograph of M.H. Figulla (1918), is a New Hittite copy with a very characteristic ductus and a preference for Akkadian forms where the Old Hittite version uses Hittite words or, more seldom, Sumerograms. The text, known as The Legend about the Queen of Kanis and the City of Zalpa, was published in transliteration and with a commentary by H. Otten (1973).

  13. ‘All Touched my Hand’: Queenly Sentiment and Royal Prerogative

    Directory of Open Access Journals (Sweden)

    Rachel Bates

    2015-05-01

    Full Text Available The Crimean War occurred during a formative period of ‘civic publicness’, a term used by John Plunkett to describe the press-mediated public duties undertaken by Victoria and Albert to affirm the monarchy’s popular constitution. The war triggered significant royal intervention into the condition of the army, one of the few sites of royal prerogative. At a time when aristocratic governance was being attacked and the privations of soldiers exposed to an unprecedented extent, the monarchy was keen both to legitimize its role as head of the army and to demonstrate its sensitivity to popular concern for the suffering of ordinary soldiers. This manifested in a highly publicized leaked letter from the Queen expressing her regard for ‘her troops’, the royal family’s visits to wounded soldiers, and the distribution of the Crimean Medal at a special ceremony, which portrayed the accessibility of the Queen through the use of touch. This article explores the symbolism and impetus of these occurrences and assesses the reception of royal intervention in the press. The few assessments of royal influence during the Crimean War have focused largely on Victoria’s personal fascination with the progress of the war and her soldiers. This article explores instead the wider, political significance of the army as extension of the royal family. The Liberal press and artists responded favourably to demonstrations of the Queen’s maternal sympathy for the troops, but my article will point to a hidden struggle to assert the Crown’s authority. Normal 0 false false false EN-GB X-NONE X-NONE

  14. Metal distribution in urban soil around steel industry beside Queen Alia Airport, Jordan.

    Science.gov (United States)

    Al-Khashman, Omar A; Shawabkeh, Reyad A

    2009-12-01

    The objective of this study was to assess the extent and severity of metal contamination in urban soil around Queen Alia Airport, Jordan. Thirty-two soil samples were collected around steel manufacturing plants located in the Al-Jiza area, south Jordan, around the Queen Alia Airport. The samples were obtained at two depths, 0-10 and 10-20 cm, and were analyzed by atomic absorption spectrophotometry for lead (Pb), zinc (Zn), cadmium (Cd), iron (Fe), copper (Cu) and chromium (Cr) levels. The physicochemical factors believed to affect the mobility of metals in the soil of the study area were also examined, including pH, electrical conductivity, total organic matter, calcium carbonate (CaCO(3)) content and cation exchange capacity. The high concentrations of Pb, Zn and Cd in the soil samples were found to be related to anthropogenic sources, such as the steel manufacturing plants, agriculture and traffic emissions, with the highest concentrations of these metals close to the site of the steel plants; in contrast the concentration of Cr was low in the soil sampled close to the steel plants. The metals were concentrated in the surface soil, and concentrations decreased with increasing depth, reflecting the physical properties of the soil and its alkaline pH. The mineralogical composition of the topsoil, identified by X-ray diffraction, was predominantly quartz, calcite, dolomite and minor minerals, such as gypsum and clay minerals. Metal concentrations were compared using one-way analysis of variance (ANOVA) to compute the statistical significance of the mean. The results of the ANOVA showed significant differences between sites for Pb, Cd and Cu, but no significant differences for the remaining metals tested. Factor analysis revealed that polluted soil occurs predominantly at sites around the steel plants and that there is no significant variation in the characteristics of the unpolluted soil, which are uniform in the study area.

  15. Dissonant Black Droplets and Black Funnels

    CERN Document Server

    Fischetti, Sebastian; Way, Benson

    2016-01-01

    A holographic field theory on a fixed black hole background has a gravitational dual represented by a black funnel or a black droplet. These states are "detuned" when the temperature of the field theory near the horizon does not match the temperature of the background black hole. In particular, the gravitational dual to the Boulware state must be a detuned solution. We construct detuned droplets and funnels dual to a Schwarzschild background and show that the Boulware phase is represented by a droplet. We also construct hairy black droplets associated to a low-temperature scalar condensation instability and show that they are thermodynamically preferred to their hairless counterparts.

  16. Synthesis of Nanoporous TiO2 and Its Potential Applicability for Dye-Sensitized Solar Cell Using Antocyanine Black Rice

    Directory of Open Access Journals (Sweden)

    Brian Yuliarto

    2010-01-01

    Full Text Available Nanoporous mesostructure TiO2 powders were synthesized by sol-gel method, with TiCl4 as a precursor in methanol solution. The Pluronic PE 6200 of block copolymer was used as the pores template. It was found from XRD measurements, both at 400∘C and 450∘C calcination temperatures, that the sol-gel technique yielded the nanoporous TiO2 with anatase phase. Based on N2 adsorption characterization using BET method, the TiO2 samples have surface area of 108 m2/g and 88 m2/g for calcination temperatures of 400∘C and of 450∘C, respectively. From small-angle neutron scattering (SANS patterns, TiO2 samples were observed to have nanoporous structures with pore sizes between 22–24 nm. The TiO2 also have order degree which depends on the calcination temperature. The potential applicability of the resulting TiO2 is confirmed for dye-sensitized solar cell (DSSC, composed of nanoporous anatase TiO2 and natural dye from antocyanine black rice. UV-Vis measurement of dye extracted from the black rice indicated that the antocyanine chelate can propagate into the TiO2 nanoporous network. The short circuit photocurrent density (Jsc under 100 mWcm−2 reached 1.287 mAcm−2 with open circuit photovoltage (Voc of 550 mV and the fill factor of 33.4%. The results show that the hybrid organic-inorganic structures are very attractive for future low-cost devices.

  17. Lifetime of Nano-Structured Black Silicon for Photovoltaic Applications

    DEFF Research Database (Denmark)

    Plakhotnyuk, Maksym; Davidsen, Rasmus Schmidt; Schmidt, Michael Stenbæk;

    2016-01-01

    In this work, we present recent results of lifetime optimization for nano-structured black silicon and its photovoltaic applications. Black silicon nano-structures provide significant reduction of silicon surface reflection due to highly corrugated nanostructures with excellent light trapping pro......, respectively. This is promising for use of black silicon RIE nano-structuring in a solar cell process flow...

  18. Lifetime of Nano-Structured Black Silicon for Photovoltaic Applications

    DEFF Research Database (Denmark)

    Plakhotnyuk, Maksym; Davidsen, Rasmus Schmidt; Schmidt, Michael Stenbæk;

    2016-01-01

    In this work, we present recent results of lifetime optimization for nano-structured black silicon and its photovoltaic applications. Black silicon nano-structures provide significant reduction of silicon surface reflection due to highly corrugated nanostructures with excellent light trapping......, respectively. This is promising for use of black silicon RIE nano-structuring in a solar cell process flow...

  19. Radio protective effect of black mulberry extract on radiation-induced damage in bone marrow cells and liver in the rat

    Science.gov (United States)

    Ghasemnezhad Targhi, Reza; Homayoun, Mansour; Mansouri, Somaieh; Soukhtanloo, Mohammad; Soleymanifard, Shokouhozaman; Seghatoleslam, Masoumeh

    2017-01-01

    Ionizing radiation by producing free radicals induces tissue oxidative stress and has clastogenic and cytotoxic effects. The radio protective effect of black mulberry extract (BME) has been investigated on liver tissue and bone marrow cells in the rat. Intraperitoneal (ip) administration of 200 mg/kg BME three days before and three days after 3 Gy and 6 Gy gamma irradiation significantly reduced the frequencies of micro nucleated polychromatic erythrocytes (MnPCEs) and micro nucleated norm chromatic erythrocyte (MnNCEs) and increased PCE/PCE+NCE ratio in rat bone marrow compared to the non-treated irradiated groups. Moreover, this concentration of BME extract decreased the level of malondialdehyde (MDA) and superoxide dismutase (SOD), as well as enhanced the total thiol content and catalase activity in rat's liver compared to the non-treated irradiated groups. It seems that BME extract with antioxidant activity reduced the genotoxicity and cytotoxicity induced by gamma irradiation in bone marrow cells and liver in the rat.

  20. Prevention and therapy of squamous cell carcinoma of the rodent esophagus using freeze-dried black raspberries

    Institute of Scientific and Technical Information of China (English)

    Gary D STONER; Robeena M AZIZ

    2007-01-01

    Aim: This study was conducted to determine if short-term treatment of N-nitrosomethylbenzylamine (NMBA)-induced tumors in the rat esophagus with dietary freeze-dried black raspberries (FBR) would result in tumor regression and enhanced survival of the animals. Methods: Four-week-old male Fisher-344 ratswere administered an AIN-76A control diet and injected subcutaneously with 0.5 mg/kg NMBA once per week for 15 weeks. At 19 weeks, when rats had an average of 5-6 tumors (papillomas) per esophagus, they were given a control diet contain-ing either 5%, 10%, or 20% FBR. After 7 weeks of berry treatment, all surviving rats were killed and tumor incidence, number and volume were determined. Results:Esophageal tumor incidences, numbers and volumes in NMBA-treated rats were not influenced by any of the berry treatments. There were progressive increases in the survival of NMBA-treated rats fed 5%-20% FBR diets; however, these increases were not significant. Conclusion: FBR at 5%, 10%, and 20% of the diet had no effect on the development of NMBA-induced tumors in the rat esophagus or on animal survival when administered for 7 weeks beginning at the papilloma stage of tumor development. Thus, FBR appear to have no therapeutic value in the treatment of esophageal tumors. In contrast, dietary FBR are highly effectivein preventing the development of NMBA-induced esophageal tumors in rats when administered before and during NMBA treatment or shortly after NMBA treat-ment when the esophagi contain preneoplastic (dysplastic) lesions of varyingdegrees of severity.

  1. Preparation, characterization and evaluation of electrocatalysts supported on functionalized carbon black for polymer exchange membrane fuel cell applications; Preparacao, caracterizacao e avaliacao de eletrocatalisadores suportados em carbono funcionalizado para aplicacao em celulas a combustivel tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Marcelo do

    2008-12-18

    The fuel cell technology associated with the growing exigency of low environmental impact energy became prosperous in the world energy scenery. The fuel cell is basically a device that converts directly the chemical energy of a fuel into electrical and thermal energy with a continuous operation by the constant feed of a fuel. Especially, the carbon black Vulcan XC72 is usually employed as an electro catalyst support, and some factors as an accessible and high surface area in order to get maximum particles dispersion, pore size, adequate pore distribution and the presence of functional groups in the carbon black surface are considered fundamental characteristics for an innovative materials development. However, the Vulcan XC72 still reveals insufficient conditions for these purposes. This study consists in the preparation and in the physical chemical characterization of functionalized carbon black by hydrogen peroxide and by polymeric chains with proton conduction properties, and its posterior utilization as electro catalyst support for PEMFC and DMFC application. After the carbon functionalization, an improvement in the carbon black dispersion in water media was observed, a beneficial effect for electro catalyst preparation. It was also observed, that the functional groups and the polymeric chains worked as stabilizers in the particle growing, producing much more homogeneous electrocatalysts, exhibiting smaller average particle size. Especially, in the case of polymeric chains functionalization, a decrease in the ohmic drop was observed for this system, attributed to an improvement in the proton transference. (author)

  2. Assessment of Cellular Responses to Oxidative Stress using MCF-7 Breast Cancer Cells, Black Seed (N. Sativa L. Extracts and H2O2

    Directory of Open Access Journals (Sweden)

    Ibrahim O. Farah

    2005-12-01

    Full Text Available Black seed (N. Sativa L is an oriental spice of the family Ranunculaceae that has long been rationally used as a natural medicine for treatment of many acute as well as chronic conditions including cardiovascular disease and immunological disorders. It has been used in the treatment of diabetes, hypertension, and dermatological conditions. There have been very few studies on the effects of N. Sativa as a chemoprevention of chronic diseases as well as in cancer prevention and/or therapy. Oxidative stress is a condition that underlies many acute as well as chronic conditions. The combination and role of oxidative stress and antioxidants in vivo is still a matter of conjecture. Our objective for the present study was to expose MCF-7 breast cancer cells in vitro (as a chronic disease example to aqueous and alcohol extracts and in combination with H2O2 as an oxidative stressor. Measurement of cell survival under various concentrations and mixtures was conducted using standard cell culture techniques, exposure protocols in 96 well plates and Fluorospectrosphotometry. Following cellular growth to 90% confluencey, exposure to water (WE and ethanol (AE extracts of N. sativa and H2O2 was performed. Cell survival indices were calculated from percent survival using regression analysis. Results showed that the alcohol extract and its mixtures were able to influence the survival of MCF-7 cells (indices ranged from 357.15- 809.50 Bg/ml in descending potency for H2O2+AE to the mix of 3. In contrast, H2O2 alone reduced effectively the survival of MCF-7 cells and the least effective combinations in descending potency were AE+H2O2, WE+H2O2, AE+WE, and WE+AE+H2O2. Mixtures other than AE+H2O2 showed possible interactions and loss of potency. In conclusion, N. Sativa alone or in combination with oxidative stress was found to be effective (in vitro in influencing the survival of MCF-7 breast cancer cells, unveiling promising opportunities in the field of cancer

  3. Purification and Characterization of a Novel Hemagglutinin with Inhibitory Activity toward Osteocarcinoma Cells from Northeast China Black Beans.

    Science.gov (United States)

    Dan, Xiuli; Wong, Jack Ho; Fang, Evandro Fei; Chan, Francis Chun Wai; Ng, Tzi Bun

    2015-04-22

    In the present study, we isolated a novel hemagglutinin from an edible legume and explored its growth-inhibitory effect on osteocarcinoma and liver cancer cells. The protein was purified by liquid chromatography techniques which entailed affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on Mono Q, and gel filtration on Superdex 75 with an FPLC system. The hemagglutinating activity of this hemagglutinin was demonstrated to be ion dependent and stable over a wide range of temperature and pH values. Antiproliferative activity was observed in the tumor cell lines MG-63 and HepG2 but not in the normal cell line WRL 68. Osteocarcinoma cells treated with the hemagglutinin underwent obvious cell shrinkage, chromatin condensation, mitochondrial membrane depolarization, and apoptosis. The mRNA expression level of interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α) were found to be up-regulated to different extents after treatment of this hemagglutinin.

  4. The Black Black Woman and the Black Middle Class.

    Science.gov (United States)

    Jeffers, Trellie

    1981-01-01

    Reprint of a 1973 article that describes the discrimination that particularly dark-skinned Black women suffer, especially at the hands of a color-conscious Black middle class. Calls for dark women to look to the African appearance and working-class roots as sources of pride and strength. (GC)

  5. Deformed wing virus in western honey bees (Apis mellifera) from Atlantic Canada and the first description of an overtly-infected emerging queen.

    Science.gov (United States)

    Williams, Geoffrey R; Rogers, Richard E L; Kalkstein, Abby L; Taylor, Benjamin A; Shutler, Dave; Ostiguy, Nancy

    2009-04-01

    Deformed wing virus (DWV) in western honey bees (Apis mellifera) often remains asymptomatic in workers and drones, and symptoms have never been described from queens. However, intense infections linked to parasitism by the mite Varroa destructor can cause worker wing deformity and death within 67 h of emergence. Ten workers (eight with deformed wings and two with normal wings) and three drones (two with deformed wings and one with normal wings) from two colonies infected with V. destructor from Nova Scotia, Canada, and two newly-emerged queens (one with deformed wings and one with normal wings) from two colonies infected with V. destructor from Prince Edward Island, Canada, were genetically analyzed for DWV. We detected DWV in all workers and drones, regardless of wing morphology, but only in the deformed-winged queen. This is the first report of DWV from Atlantic Canada and the first detection of a symptomatic queen with DWV from anywhere.

  6. Functional characterisation of semen in honeybee queen (A.m.ligustica S. spermatheca and efficiency of the diluted semen technique in instrumental insemination

    Directory of Open Access Journals (Sweden)

    Andrea Galli

    2010-01-01

    Full Text Available Differences over time in the quality of semen present in the honey bee (Apis mellifera ligustica queen spermatheca werestudied. An increase in the non-vital spermatozoa was shown to be evident (P>0.05 between the 12th and 24th month.The study of semen viability demonstrated that the passage of the semen to the spermatheca is due to sperm motility.In the queen inseminated with non-viable spermatozoa, no semen was detected in the spermatheca. Queens inseminatedtwice with a Hyes solution/semen mixture (1:1 stored as many spermatozoa in their spermatheca as those inseminatedonce with the classic technique. Queen replacement, oviposition and other functional characteristics were similarto those observed in the classic insemination procedure.

  7. Observation of the Mating Behavior of Honey Bee (Apis mellifera L.) Queens Using Radio-Frequency Identification (RFID): Factors Influencing the Duration and Frequency of Nuptial Flights.

    Science.gov (United States)

    Heidinger, Ina Monika Margret; Meixner, Marina Doris; Berg, Stefan; Büchler, Ralph

    2014-07-01

    We used radio-frequency identification (RFID) to record the duration and frequency of nuptial flights of honey bee queens (Apis mellifera carnica) at two mainland mating apiaries. We investigated the effect of a number of factors on flight duration and frequency: mating apiary, number of drone colonies, queen's age and temperature. We found significant differences between the two locations concerning the number of flights on the first three days. We also observed an effect of the ambient temperature, with queens flying less often but longer at high temperatures compared to lower temperatures. Increasing the number of drone colonies from 33 to 80 colonies had no effect on the duration or on the frequency of nuptial flights. Since our results agree well with the results of previous studies, we suggest RFID as an appropriate tool to investigate the mating behavior of honey bee queens.

  8. Identification of plant cells in black pigments of prehistoric Spanish Levantine rock art by means of a multi-analytical approach. A new method for social identity materialization using chaîne opératoire.

    Science.gov (United States)

    López-Montalvo, Esther; Roldán, Clodoaldo; Badal, Ernestina; Murcia-Mascarós, Sonia; Villaverde, Valentín

    2017-01-01

    We present a new multi-analytical approach to the characterization of black pigments in Spanish Levantine rock art. This new protocol seeks to identify the raw materials that were used, as well as reconstruct the different technical gestures and decision-making processes involved in the obtaining of these black pigments. For the first of these goals, the pictorial matter of the black figurative motifs documented at the Les Dogues rock art shelter (Ares del Maestre, Castellón, Spain) was characterized through the combination of physicochemical and archeobotanical analyses. During the first stage of our research protocol, in situ and non-destructive analyses were carried out by means of portable Energy Dispersive X-Ray Fluorescence spectrometry (EDXRF); during the second stage, samples were analyzed by Optical Microscopy (OM), Raman spectroscopy, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM-EDX). Two major conclusions have been drawn from these analyses: first, charred plant matter has been identified as a main component of these prehistoric black pigments; and second, angiosperm and conifer charcoal was a primary raw material for pigment production, identified by means of the archaeobotanical study of plant cells. For the second goal, black charcoal pigments were replicated in the laboratory by using different raw materials and binders and by reproducing two main chaînes opératoires. The comparative study of the structure and preservation of plant tissues of both prehistoric and experimental pigments by means of SEM-EDX underlines both a complex preparation process and the use of likely pigment recipes, mixing raw material with fatty or oily binders. Finally, the formal and stylistic analysis of the motifs portrayed at Les Dogues allowed us to explore the relationship between identified stylistic phases and black charcoal pigment use, raising new archaeological questions concerning the acquisition of know-how and the

  9. Using pleometrosis (multiple queens) and pupae transplantation to boost weaver ant (Oecophylla smaragdina) colony growth in ant nurseries

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim; Nielsen, Mogens Gissel; Peng, Renkang

    2011-01-01

    Weaver ants (Oecophylla spp.) are increasingly being used for biocontrol and are targeted for future production of insect protein in ant farms. An efficient production of live ant colonies may facilitate the utilization of these ants but the production of mature colonies is hampered by the long...... time it takes for newly established colonies to grow to a suitable size. In this study we followed the growth of newly founded O. smaragdina colonies with 2, 3 or 4 founding queens during 12 days of development, following the transplantation of 0, 30 or 60 pupae from a mature donor colony. Colony...... growth (number of individuals) increased with increasing numbers of queens (pleometrosis) as well as with the transplantation of pupae. Transplanted pupae were accepted and developed into mature workers and not only added extra individuals to the receiver colonies but also increased the egg production...

  10. Odour-evoked responses to queen pheromone components and to plant odours using optical imaging in the antennal lobe of the honey bee drone Apis mellifera L.

    Science.gov (United States)

    Sandoz, Jean-Christophe

    2006-09-01

    The primordial functional role of honey bee males (drones) is to mate with virgin queens, a behaviour relying heavily on the olfactory detection of queen pheromone. In the present work I studied olfactory processing in the drone antennal lobe (AL), the primary olfactory centre of the insect brain. In drones, the AL consists of about 103 ordinary glomeruli and four enlarged glomeruli, the macroglomeruli (MG). Two macroglomeruli (MG1 and MG2) and approximately 20 ordinary glomeruli occupy the anterior surface of the antennal lobe and are thus accessible to optical recordings. Calcium imaging was used to measure odour-evoked responses to queen pheromonal components and plant odours. MG2 responded specifically to the main component of the queen mandibular pheromone, 9-ODA. The secondary components HOB and HVA each triggered activity in one, but not the same, ordinary glomerulus. MG1 did not respond to any of the tested stimuli. Plant odours induced signals only in ordinary glomeruli in a combinatorial manner, as in workers. This study thus shows that the major queen pheromonal component is processed in the most voluminous macroglomerulus of the drone antennal lobe, and that plant odours, as well as some queen pheromonal components, are processed in ordinary glomeruli.

  11. The role of the glucose-sensing transcription factor carbohydrate-responsive element-binding protein pathway in termite queen fertility

    Science.gov (United States)

    Sillam-Dussès, David; Hanus, Robert; Poulsen, Michael; Roy, Virginie; Favier, Maryline

    2016-01-01

    Termites are among the few animals that themselves can digest the most abundant organic polymer, cellulose, into glucose. In mice and Drosophila, glucose can activate genes via the transcription factor carbohydrate-responsive element-binding protein (ChREBP) to induce glucose utilization and de novo lipogenesis. Here, we identify a termite orthologue of ChREBP and its downstream lipogenic targets, including acetyl-CoA carboxylase and fatty acid synthase. We show that all of these genes, including ChREBP, are upregulated in mature queens compared with kings, sterile workers and soldiers in eight different termite species. ChREBP is expressed in several tissues, including ovaries and fat bodies, and increases in expression in totipotent workers during their differentiation into neotenic mature queens. We further show that ChREBP is regulated by a carbohydrate diet in termite queens. Suppression of the lipogenic pathway by a pharmacological agent in queens elicits the same behavioural alterations in sterile workers as observed in queenless colonies, supporting that the ChREBP pathway partakes in the biosynthesis of semiochemicals that convey the signal of the presence of a fertile queen. Our results highlight ChREBP as a likely key factor for the regulation and signalling of queen fertility. PMID:27249798

  12. Molecular genetic studies in black families with sickle cell anemia and unusually high levels of fetal hemoglobin.

    Science.gov (United States)

    Seltzer, W K; Abshire, T C; Lane, P A; Roloff, J S; Githens, J H

    1992-01-01

    Clinical, hematologic, and molecular genetic studies are reported for five families with SS patients having unusually high fetal hemoglobin (Hb F) levels (mean 28.3%, range 19-42%). Some of the individuals were symptom-free and one was not anemic. However, some were symptomatic despite a very high Hb F. Neither the Hb F level nor the F cell distribution entirely explained the variation in clinical severity. Molecular genetic studies identified the Senegal haplotype with the associated -158 G gamma (C----T) mutation in two of the five families. The -202 G gamma (C----G) mutation was not found in any of the individuals studied. Sequencing of the gamma-globin gene promoters to detect genetic high F determinants not detectable by restriction digestion was not performed. All AS parents and AS siblings demonstrated elevated F cells when the Senegal/-158 G gamma (C----T) mutation was present with either the beta S or beta A allele. Double heterozygosity for two different high F determinants in some SS patients is suggested by the studies in at least one family. Discordance among siblings in clinical and hematologic manifestations in two families provides additional evidence for loci regulating Hb F cell production which are not linked to the beta-globin gene clusters.

  13. ‘A token of their love’: Queen Victoria Memorials in New Zealand

    Directory of Open Access Journals (Sweden)

    Mark Stocker

    2016-06-01

    Full Text Available This article provides an overview of the four metropolitan sculptural memorials to Queen Victoria in late-colonial New Zealand, which all immediately precede the colony’s Dominion status (1907. In chronological order, they were erected in Auckland, Christchurch, Wellington, and Dunedin. While the Auckland memorial was unveiled within the Queen’s lifetime, her death in 1901 catalysed the commission of more ambitious counterparts in Wellington and Dunedin, and a degree of intercity rivalry was consciously articulated in advocacy for them. The memorials reflect a Pākeha (European New Zealand sense of identity as a loyal, pro-monarchical, and imperial colony, but also as a ‘Better Britain’, with a proud sense of prosperity and achievement. Local content features prominently in two of them, notably the signing with Māori of the Treaty of Waitangi (1840 in one of the reliefs for the capital city memorial (Wellington, and an ambitious celebration of fifty years of provincial achievement in the pedestal sculpture for the Christchurch counterpart. Due to a dearth of home-grown talent, together with the belief in the artistic superiority of Britain (often known at the time as ‘Home’, British sculptors were invariably commissioned for these memorials. Cost-effectiveness, prestige, and the ability to render a realistic likeness were all criteria behind the choice of artists, with Francis John Williamson commissioned for two of them (Auckland and Christchurch. In researching this article, extensive use has been made of primary newspaper sources to document the political context of the memorials. In all of them, particularly that of Christchurch, New Zealand’s loyalty to Britain in the South African War (1899–1902 was a leading issue. Artistic and aesthetic issues and analysis were less prominent, although there was a widespread belief that the Queen should be honoured for purely symbolic and not utilitarian causes. While emphasis is given

  14. Lytton Strachey : l’historien intime de deux reines Lytton Strachey’s Intimate Biographies of Two Queens

    Directory of Open Access Journals (Sweden)

    Jeannine Hayat

    2007-01-01

    Full Text Available The British writer Lytton Strachey (1880-1932 wrote biographies of the two most eminent Queens of England: Queen Victoria (1921 and Elizabeth and Essex (1928. The two books made him a very famous historian. However, he would personally have preferred to be admired for his poetry or his plays, for he was a very gifted literary author. Nevertheless many of Strachey’s readers have appreciated his conception of biography, as a means of personal confession while studying the destiny of a public figure. Indeed the Stracheyan way of life, free from Victorian moral standards and guided by the rules of the Bloomsbury group, inspired his story of Victoria and Elizabeth. Both Queens at the end of their lives and at the height of their power carried on strange love affairs: Victoria with her Scottish gillie and Elizabeth with the Earl of Essex, thirty years her younger. In fact, both romances subtly reflect Strachey’s own love affairs. He was himself engaged in a kind of common life with Dora Carrington— the painter, thirteen years younger than him, with whom he was not sexually involved— while he engaged in numerous homosexual love affairs.

  15. Finding out egyptian gods' secret using analytical chemistry: biomedical properties of egyptian black makeup revealed by amperometry at single cells.

    Science.gov (United States)

    Tapsoba, Issa; Arbault, Stéphane; Walter, Philippe; Amatore, Christian

    2010-01-15

    Lead-based compounds were used during antiquity as both pigments and medicines in the formulation of makeup materials. Chemical analysis of cosmetics samples found in Egyptians tombs and the reconstitution of ancient recipes as reported by Greco-Roman authors have shown that two non-natural lead chlorides (laurionite Pb(OH)Cl and phosgenite Pb(2)Cl(2)CO(3)) were purposely synthesized and were used as fine powders in makeup and eye lotions. According to ancient Egyptian manuscripts, these were essential remedies for treating eye illness and skin ailments. This conclusion seems amazing because today we focus only on the well-recognized toxicity of lead salts. Here, using ultramicroelectrodes, we obtain new insights into the biochemical interactions between lead(II) ions and cells, which support the ancient medical use of sparingly soluble lead compounds. Submicromolar concentrations of Pb(2+) ions are shown to be sufficient for eliciting specific oxidative stress responses of keratinocytes. These consist essentially of an overproduction of nitrogen monoxide (NO degrees ). Owing to the biological role of NO degrees in stimulating nonspecific immunological defenses, one may argue that these lead compounds were deliberately manufactured and used in ancient Egyptian formulations to prevent and treat eye illnesses by promoting the action of immune cells.

  16. Black hole hair removal

    Science.gov (United States)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-07-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair — degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  17. Black Hole Hair Removal

    CERN Document Server

    Banerjee, Nabamita; Sen, Ashoke

    2009-01-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair, -- degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  18. Matilda, Edgith and Adelaide: conflicts between generations and the doweries of the queens in Germany

    Directory of Open Access Journals (Sweden)

    Giovanni Isabella

    2012-10-01

    Full Text Available The reconstruction of the size and geographical distribution of properties that made up the dowers of the first three Ottonian queens makes possible to see the great importance of these assets, both for their large extension, both for the relevant strategic role dues to their location. Already Henry I, the first king of the dynasty, endowed his wife Matilda with numerous curtes that belonged to the area of oldest and strong presence of the Ottonian family, namely the eastern Saxony and Thuringia. Precisely, the control of these important goods was the cause of the fight between Matilda and her son Otto I when, in 938, the mother supported the claims to the throne of her younger son Henry during a revolt against Otto. The dower of Edgith, the first wife of Otto, was made from the large curtis of Magdeburg, which became a place of great symbolic and political importance thanks to the burial of the royal couple and for its elevation to Archdiocese which was entrusted with the supervision of slavic territories east of the Elbe. The set of the assets granted in Germany by Otto to Adelaide, his second wife, it's difficult to reconstruct in detail, but it was definitely of great extent in continuity with the dower of Matilda, although compared to this the curtes were spread across a wider area encompassing both the eastern Saxony and Thuringia, both Alsace and Franconia.

  19. Integrating research & teaching: the Queen Mary, University of London module in Geodiversity & Geoconservation

    Science.gov (United States)

    Gray, M.

    2012-04-01

    The School of Geography at Queen Mary, University of London has been running a Level 6 (undergraduate) module in "Geodiversity & Geoconservation" since 2004. The course is based around the book Geodiversity: valuing and conserving abiotic nature (John Wiley, 2004) but lectures are used to update each topic based on the latest research. The course is divided into 5 parts: 1. Defining and describing geodiversity - which discusses the concept of geodiversity, its definition and the nature of the geodiversity of Planet Earth; 2. Values of, and threats to, geodiversity - a lecture on valuing geodiversity is now based around important research on the role of geodiversity in "ecosystem services" assessments. A second lecture covers the major threats to geodiversity; 3. The protected area approach - lectures here cover geological World Heritage Sites, Global Geoparks, GSSPs, and national geoconservation systems in the UK, USA and other parts of the world; 4. Protecting geodiversity in the wider landscape - the contribution of geology and geomorphology to landscape character are described, together with the role of land-use planning and policy-making in protecting geodiversity. 5. Putting it all together - lectures here emphasize that geodiversity is an important basis for geoconservation, that different geoconservation methods are appropriate to different elements of geodiversity, and that integrated geo/bio conservation is essential. A field trip to three Chalk/Quaternary Sites of Special Scientific Interest in East Sussex is included which discusses some of the planning issues that have arisen at these sites, a theme that is expanded in the lectures.

  20. Glaciation history of Queen Maud Land (Antarctica) – New exposure data from nunataks

    Energy Technology Data Exchange (ETDEWEB)

    Strub, E.; Wiesel, H. [Division of Nuclear Chemistry, University of Cologne, Cologne (Germany); Delisle, G. [Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover (Germany); Binnie, S.A.; Liermann, A.; Dunai, T.J. [Institute of Geology and Mineralogy, University of Cologne, Cologne (Germany); Herpers, U. [Division of Nuclear Chemistry, University of Cologne, Cologne (Germany); Dewald, A.; Heinze, S. [Institute of Nuclear Physics, University of Cologne, Cologne (Germany); Christl, M. [Laboratory of Ion Beam Physics, ETH Zurich (Switzerland); Coenen, H.H. [Division of Nuclear Chemistry, University of Cologne, Cologne (Germany); Institute of Nuclear Chemistry (INM-5), Research Centre Jülich (Germany)

    2015-10-15

    Terrestrial cosmogenic nuclide exposure ages for the Wohlthat Massif (Antarctica), have previously been determined. This was done with {sup 10}Be and {sup 26}Al measurements by accelerator mass spectrometry (AMS) at the AMS facility at the ETH Zurich. In order to determine the extent to which the results from the Wohlthat Massif are of regional significance, additional samples were collected during the 2007 BGR-expedition “Queenmet”. Two of the Steingarden Nunataks (isolated mountain peaks) were chosen as sampling locations, approximately 100 km south-east of the Wohlthat Massif/Queen Maud Land, at the edge of the Polar Plateau. Quartz rich samples were collected at different elevations on the nunataks to reconstruct an elevation-dependent exposure history. The in situ produced cosmogenic nuclides {sup 10}Be and {sup 26}Al in these samples were measured by AMS. During sample processing the quartz separates were prepared by two different methods (Kohl and Nishiizumi, 1992, Altmaier, 2000) and measurements were performed at two different facilities (CologneAMS und Zurich AMS) to confirm the reproducibility of the results. The new results of rock surface exposure ages reveal that the exposure of the lower nunatak to cosmic radiation started between 0.65 and 1.1 Ma ago, while the more elevated regions of the second nunatak were apparently above the ice 3–4 Ma ago.

  1. Nectar Attracts Foraging Honey Bees with Components of Their Queen Pheromones.

    Science.gov (United States)

    Liu, Fanglin; Gao, Jie; Di, Nayan; Adler, Lynn S

    2015-11-01

    Floral nectar often contains chemicals that are deterrent to pollinators, presenting potential challenges to outcrossing plant species. Plants may be able to co-opt pollinator chemical signals to mitigate the negative effects of nectar deterrent compounds on pollination services. We found that buckwheat (Fagopyrum esculentum) and Mexican sunflower (Tithonia diversifolia) produce nectar with abundant phenolics, including three components of the Apis honeybee queen mandibular pheromone (QMP). In addition, these nectars contain a non-pheromonal phenolic, chlorogenic acid (CA), which was toxic to honeybees, and T. diversifolia nectar also contained isochlorogenic acid (IA). Fresh nectar or solutions containing nectar phenolics reduced Apis individual feeding compared to sucrose solutions. However, freely foraging bees preferred solutions with QMP components to control solutions, and QMP components over-rode or reversed avoidance of CA and IA. Furthermore, prior exposure to the presence or just the odor of QMP components removed the deterrent effects of CA and IA. By mimicking the honey bee pheromone blend, nectar may maintain pollinator attraction in spite of deterrent nectar compounds.

  2. Infection dynamics in coexisting sexual and asexual host populations: support for the Red Queen hypothesis.

    Science.gov (United States)

    Vergara, Daniela; Jokela, Jukka; Lively, Curtis M

    2014-08-01

    The persistence of sexual reproduction is a classic problem in evolutionary biology. The problem stems from the fact that, all else equal, asexual lineages should rapidly replace coexisting sexual individuals due to the cost of producing males in sexual populations. One possible countervailing advantage to sexual reproduction is that, on average, outcrossed offspring are more resistant than common clones to coevolving parasites, as predicted under the Red Queen hypothesis. In this study, we evaluated the prevalence of infection by a sterilizing trematode (Microphallus sp.) in a natural population of freshwater snails that was composed of both sexual and asexual individuals (Potamopyrgus antipodarum). More specifically, we compared the frequency of infection in sexual and asexual individuals over a 5-year period at four sites at a natural glacial lake (Lake Alexandrina, South Island, New Zealand). We found that at most sites and over most years, the sexual population was less infected than the coexisting asexual population. Moreover, the frequency of uninfected sexual females was periodically greater than two times the frequency of uninfected asexual females. These results give clear support for a fluctuating parasite-mediated advantage to sexual reproduction in a natural population.

  3. Theology: Still a queen of science in the post-modern era

    Directory of Open Access Journals (Sweden)

    Erna Oliver

    2016-03-01

    Full Text Available Theology is just as relevant today as it was in the time of Aquinas who called theology ‘the queen of science’ although the knowledge-driven network society does not seem to be in agreement. By using the tools provided by the fourth revolution in the development of society, theology can, as part of the academic world of higher education that is supposed to lead society, strengthen ties with the past, seek explanations and solutions to current problems and produce guidelines for future investigation through multi- and interdisciplinary discourse. Theology can and should influence people to become positive change agents, re-shape the way in which the message of salvation is brought to the world in order to stay relevant in changing circumstances and be on the forefront of progressive transformation in society. This should be achieved through constant dialogue with other academic disciplines, the Church as institution and with society in general.

  4. Recreations in the theory of numbers the queen of mathematics entertains

    CERN Document Server

    Beiler, Albert H

    1966-01-01

    Number theory, the Queen of Mathematics, is an almost purely theoretical science. Yet it can be the source of endlessly intriguing puzzle problems, as this remarkable book demonstrates. This is the first book to deal exclusively with the recreational aspects of the subject and it is certain to be a delightful surprise to all devotees of the mathematical puzzle, from the rawest beginner to the most practiced expert. Almost every aspect of the theory of numbers that could conceivably be of interest to the layman is dealt with, all from the recreational point of view. Readers will become acquainted with divisors, perfect numbers, the ingenious invention of congruences by Gauss, scales of notation, endless decimals, Pythagorean triangles (there is a list of the first 100 with consecutive legs; the 100th has a leg of 77 digits), oddities about squares, methods of factoring, mysteries of prime numbers, Gauss's Golden Theorem, polygonal and pyramidal numbers, the Pell Equation, the unsolved Last Theorem of Fermat, a...

  5. The concentration and frequency of C. sakazakii in Queen Geraldin Hospital in Tirana

    Directory of Open Access Journals (Sweden)

    RENIS MAÇI

    2014-06-01

    Full Text Available In the last years the International Commission for Microbiological Specification for Foods ranked Cronobacter sakazakii as "Severe hazard for restricted populations, life threatening or substantial chronic sequelae or long duration"(ICMSF, 2002. The objective of this study is to control the biological risk of the hospital kitchen`s environment at the University Hospital of Obstetrics and Gynaecology "Queen Geraldin" where the powered infant formula is prepared. Efficiency of risk control must be verified through the application of microbiological monitoring plan that provides application of microbiological environmental criteria, proper cleaning of equipments used in production lines, control of the final product during their shelf live, collection of samples from the raw material, surfaces and environment as well as control measures during preparation and reconstitution of powered infant formulae. This study was performed to determine the frequency distribution of C. sakazakii and the concentration of Enterobacteriaceae in different sampling areas of the kitchen. We performed 60 samples in total. The samples were collected from the kitchen areas, and from the personel hands. At the end we quantified for Enterobacteriaceae and identified for C. sakazakii in 60 samples. We detected in two environmental samples (3.0% the presence of C. Sakazakii. Rules that should be respected to meet the highest level of microbiological safety in hospital/nursery are defined in MRA Series 10 (FAO/WHO 2004

  6. Preliminary identification of fullerenes in the lowermost Jurassic strata, Queen Charlotte Islands, British Columbia

    Science.gov (United States)

    Perry, Randall S.; Haggart, James W.; Ward, Peter D.

    2004-02-01

    The Triassic-Jurassic (TJ) mass extinction (~200 mya) event is one of the most severe in geologic history. It is also one of the most poorly understood. Few geologic sections containing the TJ boundary interval have been identified globally, and most of those are poorly preserved; the paucity of suitable stratigraphic sections has prevented corroborative geochemical studies of this interval. Recently, fullerene molecules (C60 to C200) have been shown to be present in the mass extinction boundary intervals of the Permian-Triassic (PT) event (~251.4 mya), as well as the well-known "dinosaur" extinction event of the Cretaceous-Tertiary (KT) (~65 mya). The presence of fullerenes in both these extinction intervals has been used to invoke an extraterrestrial impact cause for the extinctions. Preliminary results of laser desorption mass spectrometry (LDMS) of selected samples from the Kennecott Point TJ boundary section, Queen Charlotte Islands, British Columbia, suggest that fullerenes (C60 to ~C200) are present in the section, stratigraphically above the extinction interval (as defined by paleontological and isotopic data), but not actually within the interval itself. The presence of fullerenes may not be diagnostic of an impact event.

  7. The Big Rust and the Red Queen: Long-Term Perspectives on Coffee Rust Research.

    Science.gov (United States)

    McCook, Stuart; Vandermeer, John

    2015-09-01

    Since 2008, there has been a cluster of outbreaks of the coffee rust (Hemileia vastatrix) across the coffee-growing regions of the Americas, which have been collectively described as the Big Rust. These outbreaks have caused significant hardship to coffee producers and laborers. This essay situates the Big Rust in a broader historical context. Over the past two centuries, coffee farmers have had to deal with the "curse of the Red Queen"-the need to constantly innovate in the face of an increasing range of threats, which includes the rust. Over the 20th century, particularly after World War II, national governments and international organizations developed a network of national, regional, and international coffee research institutions. These public institutions played a vital role in helping coffee farmers manage the rust. Coffee farmers have pursued four major strategies for managing the rust: bioprospecting for resistant coffee plants, breeding resistant coffee plants, chemical control, and agroecological control. Currently, the main challenge for researchers is to develop rust control strategies that are both ecologically and economically viable for coffee farmers, in the context of a volatile, deregulated coffee industry and the emergent challenges of climate change.

  8. Selection on worker honeybee responses to queen pheromone (Apis mellifera L.)

    Science.gov (United States)

    Pankiw, T.; Winston, Mark L.; Fondrk, M. Kim; Slessor, Keith N.

    Disruptive selection for responsiveness to queen mandibular gland pheromone (QMP) in the retinue bioassay resulted in the production of high and low QMP responding strains of honeybees (Apis mellifera L.). Strains differed significantly in their retinue response to QMP after one generation of selection. By the third generation the high strain was on average at least nine times more responsive than the low strain. The strains showed seasonal phenotypic plasticity such that both strains were more responsive to the pheromone in the spring than in the fall. Directional selection for low seasonal variation indicated that phenotypic plasticity was an additional genetic component to retinue response to QMP. Selection for high and low retinue responsiveness to QMP was not an artifact of the synthetic blend because both strains were equally responsive or non-responsive to whole mandibular gland extracts compared with QMP. The use of these strains clearly pointed to an extra-mandibular source of retinue pheromones (Pankiw et al. 1995; Slessor et al. 1998; Keeling et al. 1999).

  9. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

    2007-11-15

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

  10. Black Hole Thermodynamics

    Science.gov (United States)

    Israel, Werner

    This chapter reviews the conceptual developments on black hole thermodynamics and the attempts to determine the origin of black hole entropy in terms of their horizon area. The brick wall model and an operational approach are discussed. An attempt to understand at the microlevel how the quantum black hole acquires its thermal properties is included. The chapter concludes with some remarks on the extension of these techniques to describing the dynamical process of black hole evaporation.

  11. Life inside black holes

    CERN Document Server

    Dokuchaev, V I

    2012-01-01

    We consider test planet and photon orbits of the third kind inside a black hole, which are stable, periodic and neither come out of the black hole nor terminate at the singularity. Interiors of supermassive black holes may be inhabited by advanced civilizations living on planets with the third-kind orbits. In principle, one can get information from the interiors of black holes by observing their white hole counterparts.

  12. Charged Lifshitz Black Holes

    OpenAIRE

    Dehghani, M. H.; Pourhasan, R.; Mann, R. B.

    2011-01-01

    We investigate modifications of the Lifshitz black hole solutions due to the presence of Maxwell charge in higher dimensions for arbitrary $z$ and any topology. We find that the behaviour of large black holes is insensitive to the topology of the solutions, whereas for small black holes significant differences emerge. We generalize a relation previously obtained for neutral Lifshitz black branes, and study more generally the thermodynamic relationship between energy, entropy, and chemical pot...

  13. Monopole black hole skyrmions

    OpenAIRE

    Moss, I. G.; Shiiki, N.; Winstanley, E.

    2000-01-01

    Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.

  14. Marketing for Black Alums.

    Science.gov (United States)

    Harris, Tracy A.

    1994-01-01

    Considers need for colleges and universities to develop effective marketing plan for recruitment of black students. Highlights advantages of designing marketing plan for recruitment of black alumni to assist in recruitment and retention of black students. Identifies key indicators that often hinder institutions in their recruitment of black…

  15. Black holes in binary stars

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1996-01-01

    Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

  16. The effects of black garlic ethanol extract on the spatial memory and estimated total number of pyramidal cells of the hippocampus of monosodium glutamate-exposed adolescent male Wistar rats.

    Science.gov (United States)

    Hermawati, Ery; Sari, Dwi Cahyani Ratna; Partadiredja, Ginus

    2015-09-01

    Monosodium glutamate (MSG) is believed to exert deleterious effects on various organs, including the hippocampus, likely via the oxidative stress pathway. Garlic (Alium sativum L.), which is considered to possess potent antioxidant activity, has been used as traditional remedy for various ailments since ancient times. We have investigated the effects of black garlic, a fermented form of garlic, on spatial memory and estimated the total number of pyramidal cells of the hippocampus in adolescent male Wistar rats treated with MSG. Twenty-five rats were divided into five groups: C- group, which received normal saline; C+ group, which was exposed to 2 mg/g body weight (bw) of MSG; three treatment groups (T2.5, T5, T10), which were treated with black garlic extract (2.5, 5, 10 mg/200 g bw, respectively) and MSG. The spatial memory test was carried out using the Morris water maze (MWM) procedure, and the total number of pyramidal cells of the hippocampus was estimated using the physical disector design. The groups treated with black garlic extract were found to have a shorter path length than the C- and C+ groups in the escape acquisition phase of the MWM test. The estimated total number of pyramidal cells in the CA1 region of the hippocampus was higher in all treated groups than that of the C+ group. Based on these results, we conclude that combined administration of black garlic and MSG may alter the spatial memory functioning and total number of pyramidal neurons of the CA1 region of the hippocampus of rats.

  17. The crustal structure, deformation from GPS, and seismicity related to oblique convergence along the Queen Charlotte margin, British Columbia

    Science.gov (United States)

    Bustin, Amanda M. M.

    Tectonic processes and seismic hazard along the west coast of British Columbia result from oblique convergence between the continental North America plate and the oceanic Pacific and Juan de Fuca plates. This dissertation integrates seismic and geodetic techniques to examine the tectonic interaction along these plate boundaries. The Queen Charlotte Fault zone is the transpressive boundary between the North America and Pacific plates along the northwestern margin of British Columbia. Two models have been suggested for the accommodation of the ˜20 mm/yr of convergence along the fault boundary: (1) underthrusting; (2) internal crustal deformation. Strong evidence supporting an underthrusting model is provided in this dissertation by a teleseismic receiver function analysis that defines the underthrusting slab. Forward and inverse modelling techniques were applied to receiver function data calculated at two permanent and six temporary seismic stations within the Islands. The modelling reveals a ˜10 km thick low-velocity zone dipping eastward at 28° interpreted to be underthrusting oceanic crust. The oceanic crust, which may be anisotropic, is located beneath a thin (28 km) westward shallowing (10°) continental margin. The majority of seismicity along the Queen Charlotte Fault zone plots within the modelled underthrusting crust, suggesting that these earthquakes are occurring on faults that extend down into the slab or they might be intraslab events. None of the earthquakes within the Queen Charlotte Basin have occurred deep enough to be intraslab earthquakes. The Wadati-Benioff seismicity may be inhibited beneath the basin by the hot young oceanic crust or by the short distance of underthrusting. GPS measurements have been recorded within the Queen Charlotte Islands during 8 years of campaign surveys. The crustal velocity field derived from the GPS data indicates northward margin-oblique motion of 10--15 mm/yr. Comparisons of the observed velocities with elastic

  18. On Accelerated Black Holes

    CERN Document Server

    Letelier, P S; Letelier, Patricio S.; Oliveira, Samuel R.

    1998-01-01

    The C-metric is revisited and global interpretation of some associated spacetimes are studied in some detail. Specially those with two event horizons, one for the black hole and another for the acceleration. We found that the spacetime fo an accelerated Schwarzschild black hole is plagued by either conical singularities or lack of smoothness and compactness of the black hole horizon. By using standard black hole thermodynamics we show that accelerated black holes have higher Hawking temperature than Unruh temperature. We also show that the usual upper bound on the product of the mass and acceleration parameters (<1/sqrt(27)) is just a coordinate artifact. The main results are extended to accelerated Kerr black holes. We found that they are not changed by the black hole rotation.

  19. Slip Partitioning, Crustal Tectonics and Deformation of the Queen Charlotte Margin and Northern Vancouver Island

    Science.gov (United States)

    Hippchen, Sabine

    Part I of this thesis investigates current deformation in western British Columbia from northern Vancouver Island in the south to Haida Gwaii in the north. The area is characterized by transition from the Cascadia subduction zone to the Queen Charlotte transform fault. The tectonic setting involves interactions between the Pacific, North America, Juan de Fuca, and Explorer plates, and the Winona block, involving a number of plate boundaries: the mainly strike-slip Queen Charlotte, Revere-Dellwood-Wilson and Nootka faults, the Explorer ridge, and the Cascadia subduction zone. Using GPS campaign data from 1993 to 2008 I derive a new crustal velocity field for Northern Vancouver Island and the adjacent mainland, and integrate it with previous velocity fields developed for Haida Gwaii, southern Vancouver Island and the adjacent mainland. The northern limit of the subduction zone is confirmed to be at Brooks Peninsula, where the direction of the crustal motion changes abruptly from ENE to NNE. I use viscoelastic models to explore what percentage of the observed deformation is transient, related to the earthquake cycle, and how much is permanent ongoing deformation, distributed off the continental margin. Previous authors have developed two competing end-member models that can each explain how the Pacific/North America plate convergence is accommodated off Haida Gwaii. These models assume either internal crustal shortening or underthrusting of the Pacific plate. These new GPS data allow me to conclude that underthrusting does occur, and that a small component (Haida Gwaii the distinction between transient and long-term deformation is not as clear; however, I conclude that transient deformation alone cannot fully explain the observed velocities, and so long-term deformation likely must also occur. Part II of the thesis investigates the updip and downdip limits of the seismogenic zone of the Sumatra megathrust fault. Temperature and downdip changes in formation composition

  20. Being Blue in Hawai‘i: Politics, Affect, and the Last Queen of Hawai‘i

    Directory of Open Access Journals (Sweden)

    Bruce Harvey

    2011-12-01

    Full Text Available For Hawaiian self-rule activists, who retain ties to the land and forms of sociality emerging out of the land, the US is regarded as an occupier force, and nonnative ownership, whether white or Japanese, a blighting catastrophe justifying resentment and rage. The demise of the Kingdom of Hawai‘i, when an oligarchy of US white settler businessmen overthrew Queen Liliʻuokalani (1838–1917 in 1893, reduced aloha ‘āina (or land-cherishing to a ghostly affect; to be blue in Hawai‘i, today, is to be in a state of ongoing and implacable mourning. This essay explores several affective historical scenes of Hawaiian injury: from the early nineteenth century, when Protestant missionaries began their effort to transform Hawaiian sensibilities; onto the Queen’s forced abdication via the McKinley 1898 annexation; and finally to the contemporary era of Hawaiian nationalist protest. The Queen’s story, contextualized by brief case studies of native bereavement earlier in the century (David Malo and Henry Obookiah, leads in the final sections to a query of the relation of affect—whether melancholic or rageful—to political effect. The essay concludes with a critical coda on President Obama’s declaration (in a speech given in Hawai‘i, before elected that the “Aloha spirit” is “what America is looking for right now.” The problem with liberalism, as it is with certain versions of local/global studies, is that wounded, grievous affect cannot readily be translated (there is no efficacious transference into specific political praxis.

  1. METRIC SURVEY OF THE MONUMENT OF QUEEN ELISENDA'S TOMB IN THE MONASTERY OF PEDRALBES, BARCELONA

    Directory of Open Access Journals (Sweden)

    M. A. Núñez

    2012-09-01

    Full Text Available When an urban development is planned the cartography of this territory is necessary, in the same way before starting a project to rehabilitate a monument the graphic information about it has to be available. At present, different techniques are available which allow to obtain three-dimensional models with a different accuracy level and runtimes.This paper shows the work carried out to obtain the graphic information and three-dimensional models that are necessary for the rehabilitation project of the tomb of Queen Elisenda in the Monastery of Pedralbes, Barcelona (Spain. This monument has the peculiarity of being symmetrical about the wall separating monastery church and the cloister. To do this, different techniques have been used that allow us to obtain an accurate model and as complete as possible, for the analysis of the construction process of the monument. In order to achieve the complete architectural survey the integration of laser scanning and photogrammetric data, and CAD models has been necessary. Due to the detail of the sculptures and the Queen’s sarcophagus two sensors, with different resolution, range and accuracy, have been used to obtain the laser scanning data. Stereo pairs have been taken to obtain the 3D model of these elements to complete the model and obtain an ortophotography.In this way, a comparative analysis of both techniques has been carried out, in order to decide which one is the suitable for certain application. This investigation has been restricted to the tomb, in the two symmetrical parts of the monument.

  2. Raising infanta Catalina de Aragón to be Catherine queen of England

    Directory of Open Access Journals (Sweden)

    Earenfight, Theresa M.

    2016-06-01

    Full Text Available This study examines the household of infanta Catalina de Aragón, youngest daughter of Isabel of Castile and Fernando of Aragon, to demonstrate how trusted women at court provided the foundation for Catalina’s transformation from Spanish infanta to English queen. Using account records from the court of her mother and records from English royal sources, this essay focuses four women in particular –Inés Vanegas, María de Rojas, María de Salinas, Elvira Manuel– who were deeply embedded in a complex kin and patronage network at court. Their tutelage and loyalty prepared Catalina to navigate the complexity of court politics in Tudor England.Este estudio examina la casa de la infanta Catalina de Aragón, hija menor de Isabel de Castilla y Fernando de Aragón, para mostrar cómo las mujeres de confianza de la corte constituyeron la base de la transformación de Catalina de infanta espanola en reina inglesa. Utilizando los libros de cuentas de la casa y corte de su madre y documentos reales ingleses, este ensayo se centra en cuatro mujeres en particular –Inés Vanegas, María de Rojas, María de Salinas y Elvira Manuel–, inmersas en unas complejas redes de parentesco y de patronazgo dentro de la propia corte. Su tutela y lealtad prepararon a Catalina para sortear los entresijos de la política cortesana de la Inglaterra de los Tudor.

  3. Assessment of alteration processes on circumstellar and interstellar grains in Queen Alexandra Range 97416

    Science.gov (United States)

    Bose, Maitrayee; Zega, Thomas J.; Williams, Peter

    2014-08-01

    Insight into the presolar and interstellar grain inventory of the CO3 chondrite Queen Alexandra Range (QUE) 97416 is gained through correlated secondary ion mass spectrometry (SIMS), transmission electron microscopy (TEM), and synchrotron-based X-ray absorption near-edge structure spectroscopy (XANES). Only one presolar silicate grain [O17/O16=(9.96±0.75)×10-4; O18/O16=(19.49±0.96)×10-4] that may have formed in a low-mass Red Giant or Asymptotic Giant Branch star occurs in the coarse-grained matrix of QUE 97416. No other presolar grains were identified. Although presolar grains are rare in QUE 97416, numerous (898±259 ppm) 15N-rich domains (δN15∼+1447‰ to +3069‰) occur in the thin section. Based on TEM of an extracted section, two 15N-rich domains are amorphous, C-bearing, and texturally uniform, and they are embedded in a ferromagnesian silicate matrix with varied grain sizes. The individual 15N-rich organic regions with high δN15 (+2942±107‰ and +2341±140‰) exhibit diverse carbon functional groups, such as aromatic, vinyl-keto, amidyl, and carboxylic functionality, while the nitrogen XANES reveals traces of nitrile functionality. QUE 97416 appears to have escaped aqueous alteration based on the absence of hydrated minerals but is thermally altered, which could have resulted in the destruction of presolar grains. However, this process at >400 °C metamorphic temperatures was inefficient in destroying the carriers of N isotope anomalies, which may indicate the resistant nature of the organic carriers and/or the limited extent of thermal metamorphism on the QUE 97416 parent body.

  4. Lactobacillus bombi sp. nov., from the digestive tract of laboratory-reared bumblebee queens (Bombus terrestris).

    Science.gov (United States)

    Killer, J; Votavová, A; Valterová, I; Vlková, E; Rada, V; Hroncová, Z

    2014-08-01

    Three bacterial strains belonging to the genus Lactobacillus were isolated from the digestive tracts of laboratory-reared bumblebee queens (Bombus terrestris) using MRS agar under anaerobic conditions. The isolates were identified according to 16S rRNA gene sequence analysis as undescribed members of the genus Lactobacillus, with the highest 16S rRNA gene sequence similarity (96.9 %) to the uncharacterized bacterial strain Lactobacillus sp. Mboho2r2 isolated from the stomach of a European honeybee (Apis mellifera). Lactobacillus tucceti was found to be the closest related species with a validly published name, with 92.9 % 16S rRNA gene sequence similarity to the type strain. However, phylogenetic analyses based on different markers revealed that this species is phylogenetically very distant from the novel strains. The DNA G+C content of the proposed type strain BTLCH M1/2(T) is 37.8 mol%. The fatty acids C(19 : 1)ω6c and/or C(19 : 0) cyclo ω10c/19ω6, C(18 : 1)ω9c and C(16 : 0) were predominant in all strains. Diphosphatidylglycerol, phosphatidylglycerol, a phospholipid, seven glycolipids and two phosphoglycolipids were detected in the novel strains. Growth was observed at 47 °C. The peptidoglycan type A4α L-Lys-D-Asp was determined for strain BTLCH M1/2(T). Genotypic characteristics and phylogenetic analyses based on the phylogenetic markers hsp60, pheS, rpoA and tuf as well as phenotypic characteristics and the results of chemotaxonomic analyses confirmed that the new isolates belong to a novel species of the genus Lactobacillus, for which the name Lactobacillus bombi sp. nov. is proposed. The type strain is BTLCH M1/2(T) ( = DSM 26517(T) = CCM 8440(T)).

  5. Cryopreservation of Queen Honeybee(Apis mellifera camica)Born Worker Eggs by Vitrification

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-yong; XUE Yun-bo; WANG Zhi; LI Xing-an

    2010-01-01

    Many species of insect egg can be targeted individually or(and)collectively for cryopreservation by vitrification.However,there has been no report on cryopreservation of honeybee eggs by vitrification.In an attempt to define a preliminary procedure of cryopreservation of honeybee eggs by vitrification,queen honeybee born worker eggs(worker eggs)were stored through vitrification in liquid nitrogen up to 1 h,and then post-vitrification survival of the vitrified worker eggs in vitro and their hatching rates during maturation in vivo were observed using microscopic and close visual inspections.The procedure of cryopreservation by vitrification included dechorionation with sodium hypochlorite and permeabilization with isopropyl alcohol; equilibration by addition of loading solution(i.e.,25% vitrification storage solution)and dehydration by gradual replacement of loading solution with vitrification storage solution; cooling in liquid nitrogen vapor right before droplet vitrification in liquid nitrogen; and recovery in liquid nitrogen vapor right after storage in liquid nitrogen,thawing at temperature of thawing medium(5% sucrose in TC 100-insect medium)and rehydration by gradual replacement of vitrification storage solution with rehydration solution(5% fetal bovine serum in TC 100-insect medium).It was found that among the worker eggs experiencing cyropreservation by vitrification,1.25% of them were successfully passed through the four life stages,viz.,egg,larva,pupa,and adult.In summary,it can be inferred that although a majority of worker eggs were dead after cyroprescrvation by vitrification,a few of them were developed into larvae,pupae,and finally emerged as adults.

  6. Geoarchaeological investigations of a Mesolithic-Neolithic Sedimentary Sequence from Queens Sedgemoor, Somerset, UK

    Science.gov (United States)

    Hill, Tom; Whittaker, John; Brunning, Richard; Law, Matthew; Bell, Martin; Wilkinson, Keith

    2016-04-01

    A geoarchaeological investigation was undertaken at Queens Sedgemoor in Somerset, southwest England, as part of the English Heritage funded project 'the Mesolithic wetland/dryland edge in Somerset' (EH 6624). This project was designed to address the National Heritage Protection Plan (Topic 4G) associated with the assessment of the character and significance of sedimentary and wetland archaeology. As part of the project, a sediment core extracted from the site and has undergone high resolution radiocarbon dating, with subsequent detailed and directed micropalaeontological analyses (pollen, diatom, foraminifera, ostracoda, mollusca) focussing on the sedimentary sequence associated with the Mesolithic and early Neolithic periods. The presentation summarises the results of this multiproxy analyses and explains how it has assisted in understanding the landscape during a period of substantial prehistoric importance in southwest England. The sedimentary sequence dates back to the Mesolithic period (7.6ky BP) and the microfossil evidence indicates hydroseral succession has taken place, with the initial establishment of a freshwater lake, prior to undergoing terrestrialisation and the eventual development of a raised bog. Holocene sea-level change also influenced the sedimentary archive. Due to a rise in relative sea level c. 6.7ky BP, subsequent coastal inundation and estuarine sedimentation took also place and is hereby associated with the Lower Wentlooge Formation of the Somerset Levels. Although poor pollen preservation was encountered within the section specifically associated with the Mesolithic-Neolithic transition, a clear picture of landscape change is presented for the sedimentary archive, with evidence indicative of landscape modification by humans since the late Mesolithic.

  7. Sable Queens in Bondage: Reading, Independent Study, and Research on the American Slave Narrative.

    Science.gov (United States)

    Denniston, Dorothy L.

    This paper examines the scope and historical significance of biographies and autobiographies of ex-slaves. The document focuses primarily on accounts of black women published from 1820-1860, but also discusses several narratives from colonial times. Exploits of famous women slaves including Harriet Tubman and Sojourner Truth are analyzed along…

  8. Changes in the size of cephalic salivary glands of Apis mellifera and Scaptotrigona postica (Hymenoptera: Apidae queens and workers in different life phases

    Directory of Open Access Journals (Sweden)

    Silvana B. Poiani

    2010-01-01

    Full Text Available The bee species of the Apinae, in addition to the thoracic salivary glands, possess a pair of cephalic glands originating as branches of the excretory duct that crosses the head. These glands are known as cephalic salivary or labial cephalic glands. The degree of development of these glands in newly emerged, nurse and forager workers and virgin and egg-laying queens of Apis mellifera Linnaeus, 1758 and Scaptotrigona postica Latreille, 1807 were evaluated by measuring the secretory alveolar units. The area of the secretory alveoli, measured in total gland preparations, was used to evaluate differences in size. In both species, gland size was found to increase progressively from newly emerged workers to foragers and from virgin to egg-laying queens. A statistical analysis revealed significant differences (p < 0.05 in the area of gland alveoli of workers in different life phases in both species, and between S. postica virgin and egg-laying queens, but not between A. mellifera queens. In the case of workers, this suggests cephalic salivary gland secretion has a function in forager activity and, in queens, a possible pheromonal function.

  9. Ao38, a new cell line from eggs of the black witch moth, Ascalapha odorata (Lepidoptera: Noctuidae, is permissive for AcMNPV infection and produces high levels of recombinant proteins

    Directory of Open Access Journals (Sweden)

    Zhang Sheng

    2010-07-01

    Full Text Available Abstract Background The insect cell line is a critical component in the production of recombinant proteins in the baculovirus expression system and new cell lines hold the promise of increasing both quantity and quality of protein production. Results Seventy cell lines were established by single-cell cloning from a primary culture of cells derived from eggs of the black witch moth (Ascalapha odorata; Lepidoptera, Noctuidae. Among 8 rapidly growing lines, cell line 38 (Ao38 was selected for further analysis, based on susceptibility to AcMNPV infection and production of secreted alkaline phosphatase (SEAP from a baculovirus expression vector. In comparisons with low-passage High Five (BTI-Tn-5B1-4 cells, infected Ao38 cells produced β-galactosidase and SEAP at levels higher (153% and 150%, respectively than those measured from High Five cells. Analysis of N-glycans of SEAP produced in Ao38 cells revealed two N-glycosylation sites and glycosylation patterns similar to those reported for High Five and Sf9 cells. Glycopeptide isoforms consisted of pauci- or oligomannose, with and without fucose on N-acetylglucosamine(s linked to asparagine residues. Estimates of Ao38 cell volume suggest that Ao38 cells are approximately 2.5× larger than Sf9 cells but only approximately 74% of the size of High Five cells. Ao38 cells were highly susceptible to AcMNPV infection, similar to infectivity of Sf9 cells. Production of infectious AcMNPV budded virions from Ao38 cells peaked at approximately 4.5 × 107 IU/ml, exceeding that from High Five cells while lower than that from Sf9 cells. Ao38 cells grew rapidly in stationary culture with a population doubling time of 20.2 hr, and Ao38 cells were readily adapted to serum-free medium (Sf-900III and to a suspension culture system. Analysis of Ao38 and a parental Ascalapha odorata cell line indicated that these lines were free of the alphanodavirus that was recently identified as an adventitious agent in High Five cell

  10. Density and reproduction of the Queen Conch EUSTROMBUS gigas (Mesogastropoda: Strombidae) at Cabo Cruz, Desembarco del Granma National Park, Cuba.

    Science.gov (United States)

    Cala, Yuself R; de Jesús-Navarrete, Alberto; Ocaña, Frank A; Oliva-Rivera, José

    2013-06-01

    The queen conch Eustrombus gigas is an important fisheries resource in the Caribbean region. In Cuba Island the studies about this resource are very scarce and particularly in the Southeastern regions of the country. With the aim to get important fishery information about this gastropod, adult Queen Conch density and frequency of reproductive activity were evaluated in Cabo Cruz, Cuba, during 2009-2010. Data from three seasons were obtained (rainy, dry and cold fronts periods) from three different areas: Farito, Guafe and Laguna. The highest density was observed in cold fronts season (468.5 ind./ha) and the lowest occurred during the dry season (268.5 ind./ha). The highest density was reported at Laguna (520.4 ind./ha) and the lowest at Farito (290.9ind./ha). In total, 158 reproductive events were observed. The highest frequency was reported in rainy season (36%), followed by dry (9%) and cold fronts (5%) seasons. Reproductive behavior (mating and egg laying) was related to temperature and photoperiod. Reproductive activity was observed during the whole year, which suggests the existence of an important Queen Conch reserve in the Southeastern region of Cuba and an apparently self-sufficient population for recruitment. From our results we may conclude that, the population's sustainable exploitation is viable if the following management measures are observed: functional zoning within the area, rotation of fishing areas and a closed season. We recommend that the Laguna site should be protected as a reproduction zone and banned for fishing activities.

  11. Identification of plant cells in black pigments of prehistoric Spanish Levantine rock art by means of a multi-analytical approach. A new method for social identity materialization using chaîne opératoire

    Science.gov (United States)

    Roldán, Clodoaldo; Badal, Ernestina; Murcia-Mascarós, Sonia; Villaverde, Valentín

    2017-01-01

    We present a new multi-analytical approach to the characterization of black pigments in Spanish Levantine rock art. This new protocol seeks to identify the raw materials that were used, as well as reconstruct the different technical gestures and decision-making processes involved in the obtaining of these black pigments. For the first of these goals, the pictorial matter of the black figurative motifs documented at the Les Dogues rock art shelter (Ares del Maestre, Castellón, Spain) was characterized through the combination of physicochemical and archeobotanical analyses. During the first stage of our research protocol, in situ and non-destructive analyses were carried out by means of portable Energy Dispersive X-Ray Fluorescence spectrometry (EDXRF); during the second stage, samples were analyzed by Optical Microscopy (OM), Raman spectroscopy, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM-EDX). Two major conclusions have been drawn from these analyses: first, charred plant matter has been identified as a main component of these prehistoric black pigments; and second, angiosperm and conifer charcoal was a primary raw material for pigment production, identified by means of the archaeobotanical study of plant cells. For the second goal, black charcoal pigments were replicated in the laboratory by using different raw materials and binders and by reproducing two main chaînes opératoires. The comparative study of the structure and preservation of plant tissues of both prehistoric and experimental pigments by means of SEM-EDX underlines both a complex preparation process and the use of likely pigment recipes, mixing raw material with fatty or oily binders. Finally, the formal and stylistic analysis of the motifs portrayed at Les Dogues allowed us to explore the relationship between identified stylistic phases and black charcoal pigment use, raising new archaeological questions concerning the acquisition of know-how and the

  12. Cos, biografia i cultures juvenils. Els estudis de cas del moviment skinhead i dels latin kings & queen a catalunya

    OpenAIRE

    Porzio, Laura

    2009-01-01

    El objetivo teórico de mi tesis ha sido hacer dialogar la corriente de estudio sobre las culturas juveniles y la Teoría Social del Cuerpo, perspectiva metodológica dónde este se vuelve un sujeto y se construye socialmente, todo interpretando los relatos biográficos de chicas y chicos miembros de los skinheads antifeixistes y de los latin kings & queens en Catalunya. Estas historias de vida son los relatos incorporados (embodiment) de cada chica y de cada chico, que tienen experiencias sobre s...

  13. Extremal Hairy Black Holes

    CERN Document Server

    Gonzalez, P A; Saavedra, Joel; Vasquez, Yerko

    2014-01-01

    We consider a gravitating system consisting of a scalar field minimally coupled to gravity with a self-interacting potential and an U(1) electromagnetic field. Solving the coupled Einstein-Maxwell-scalar system we find exact hairy charged black hole solutions with the scalar field regular everywhere. We go to the zero temperature limit and we study the effect of the scalar field on the near horizon geometry of an extremal black hole. We find that except a critical value of the charge of the black hole there is also a critical value of the charge of the scalar field beyond of which the extremal black hole is destabilized. We study the thermodynamics of these solutions and we find that if the space is flat then at low temperature the Reissner-Nordstr\\"om black hole is thermodynamically preferred, while if the space is AdS the hairy charged black hole is thermodynamically preferred at low temperature.

  14. Astrophysical black holes

    CERN Document Server

    Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

    2016-01-01

    Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

  15. Black Branes as Piezoelectrics

    CERN Document Server

    Armas, Jay; Obers, Niels A

    2012-01-01

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

  16. Black branes as piezoelectrics.

    Science.gov (United States)

    Armas, Jay; Gath, Jakob; Obers, Niels A

    2012-12-14

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

  17. Perturbations around black holes

    CERN Document Server

    Wang, B

    2005-01-01

    Perturbations around black holes have been an intriguing topic in the last few decades. They are particularly important today, since they relate to the gravitational wave observations which may provide the unique fingerprint of black holes' existence. Besides the astrophysical interest, theoretically perturbations around black holes can be used as testing grounds to examine the proposed AdS/CFT and dS/CFT correspondence.

  18. Observation of the Mating Behavior of Honey Bee (Apis mellifera L. Queens Using Radio-Frequency Identification (RFID: Factors Influencing the Duration and Frequency of Nuptial Flights

    Directory of Open Access Journals (Sweden)

    Ina Monika Margret Heidinger

    2014-07-01

    Full Text Available We used radio-frequency identification (RFID to record the duration and frequency of nuptial flights of honey bee queens (Apis mellifera carnica at two mainland mating apiaries. We investigated the effect of a number of factors on flight duration and frequency: mating apiary, number of drone colonies, queen’s age and temperature. We found significant differences between the two locations concerning the number of flights on the first three days. We also observed an effect of the ambient temperature, with queens flying less often but longer at high temperatures compared to lower temperatures. Increasing the number of drone colonies from 33 to 80 colonies had no effect on the duration or on the frequency of nuptial flights. Since our results agree well with the results of previous studies, we suggest RFID as an appropriate tool to investigate the mating behavior of honey bee queens.

  19. The role of the glucose-sensing transcription factor carbohydrate-responsive element-binding protein pathway in termite queen fertility

    DEFF Research Database (Denmark)

    Sillam-Dussès, David; Hanus, Robert; Thomas-Poulsen, Michael

    2016-01-01

    Termites are among the few animals that themselves can digest the most abundant organic polymer, cellulose, into glucose. In mice and Drosophila, glucose can activate genes via the transcription factor carbohydrate-responsive element-binding protein (ChREBP) to induce glucose utilization and de...... novo lipogenesis. Here, we identify a termite orthologue of ChREBP and its downstream lipogenic targets, including acetyl-CoA carboxylase and fatty acid synthase. We show that all of these genes, including ChREBP, are upregulated in mature queens compared with kings, sterile workers and soldiers...... in eight different termite species. ChREBP is expressed in several tissues, including ovaries and fat bodies, and increases in expression in totipotent workers during their differentiation into neotenic mature queens. We further show that ChREBP is regulated by a carbohydrate diet in termite queens...

  20. Asymptotic Black Holes

    CERN Document Server

    Ho, Pei-Ming

    2016-01-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  1. Asymptotic black holes

    Science.gov (United States)

    Ho, Pei-Ming

    2017-04-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  2. Black Hole Thermodynamics

    CERN Document Server

    Carlip, S

    2014-01-01

    The discovery in the early 1970s that black holes radiate as black bodies has radically affected our understanding of general relativity, and offered us some early hints about the nature of quantum gravity. In this chapter I will review the discovery of black hole thermodynamics and summarize the many independent ways of obtaining the thermodynamic and (perhaps) statistical mechanical properties of black holes. I will then describe some of the remaining puzzles, including the nature of the quantum microstates, the problem of universality, and the information loss paradox.

  3. Chloroform extract of aged black garlic attenuates TNF-α-induced ROS generation, VCAM-1 expression, NF-κB activation and adhesiveness for monocytes in human umbilical vein endothelial cells.

    Science.gov (United States)

    Lee, Eun Na; Choi, Young Whan; Kim, Hye Kyung; Park, Jin Kyeong; Kim, Hyo Jin; Kim, Myoung June; Lee, Hee Woo; Kim, Ki-Hyung; Bae, Sun Sik; Kim, Bong Seon; Yoon, Sik

    2011-01-01

    Aged black garlic is a type of fermented garlic (Allium sativum) which has been used in Oriental countries for a long time because of various biological properties of garlic derivatives. The current study explored the potential of the chloroform extract of aged black garlic (CEABG) in attenuating the activities of adhesion molecules in tumor necrosis factor-α (TNF-α)-stimulated human umbilical vein endothelial cells (HUVECs). The study was performed on HUVECs that were pretreated with 30 μg/mL of CEABG before TNF-α treatment. Treatment of HUVECs with CEABG significantly inhibited TNF-α-induced reactive oxygen species (ROS) formation. HUVECs treated with CEABG showed markedly suppressed TNF-α-induced mRNA expression of VCAM-1, but little alteration in ICAM-1 and E-selectin mRNA expression. CEABG treatment also significantly decreased the TNF-α-induced cell surface and total protein expression of VCAM-1 without affecting ICAM-1 and E-selectin expression. In addition, treatment of HUVECs with CEABG markedly reduced THP-1 monocyte adhesion to TNF-α-stimulated HUVECs. Furthermore, CEABG significantly inhibited NF-κB transcription factor activation in TNF-α-stimulated HUVECs. The data provide new evidence of the antiinflammatory properties of CEABG that may have a potential therapeutic use for the prevention and treatment of vascular diseases such as atherosclerosis through mechanisms involving the inhibition of VCAM-1 expression and NF-κB activation in vascular endothelial cells.

  4. New Maps for Old: a Topological Approach to "the Faerie Queene" and Shakespeare's History Plays

    Science.gov (United States)

    Graney, Kathleen M.

    1994-01-01

    When Nicholas Copernicus published De revolutionibus in 1543, his announced discoveries both displaced humankind from its former place at the center of the universe and enlarged the boundaries of that universe beyond anything that had been imagined before. These discoveries evoked in men and women of the late-sixteenth century a new consciousness of both cosmic space and of psychological spaces within themselves, spaces for self-definition made available by the breakdown of the traditional, hierarchical world view. This re-vision of space is evident in almost every aspect of the culture of Elizabethan England, from its science and art to the accounts of New World voyagers. In the works of Edmund Spenser and William Shakespeare, this spatial awareness manifests itself "topologically" --that is, in the relationship between places in their epic and dramatic works that can be identified as "inside" or "outside" and in the kinds of actions associated with each place. In Books One and Two of The Faerie Queene Spenser uses space both topographically and topologically. He maps the journeys of his knights through Fairyland by means of references to allegorical structures and features of the mythical landscape. At the same time, he contrasts inside spaces, where the knights struggle psychologically to define themselves in terms of certain moral virtues, and outside spaces, where that "self" intersects with Spenser's myth of English history. In his earliest chronicle plays of the 1580s and '90s Shakespeare also depicts English history topographically, as a series of epic confrontations enacted in outside, public spaces bearing familiar place -names. With Richard III, however, he begins to dramatize that history as related to moments of self-discovery achieved by the central character within the privacy of inside spaces and involving some conflict between the values of public and private life. Unlike Spenser, whose characters ultimately define themselves in terms of some value

  5. A review of methods used in some European countries for assessing the quality of honey bee queens through their physical characters and the performance of their colonies

    DEFF Research Database (Denmark)

    Hatjina, Fani; Bienkowska, Malgorzata; Charistos, Leonidas

    2014-01-01

    The term “quality” in relation to queens and drones refers to certain quantitative physical and / or behavioural characters. It is generally believed that a high quality queen should have the following physical characteristics: high live weight; high number of ovarioles; large size of spermatheca......; high number of spermatozoa in spermatheca; and be free from diseases and pests. It is, however, also known that the performance of a honey bee colony is the result of its queen’s function as well as of that of the drones that mated with her. These two approaches are often considered together and give...

  6. The Queen Charlotte Fault, British Columbia: seafloor anatomy of a transform fault and its influence on sediment processes

    Science.gov (United States)

    Barrie, J. Vaughn; Conway, Kim W.; Harris, Peter T.

    2013-08-01

    The Queen Charlotte Fault Zone (QCFZ) off western Canada is the northern equivalent to the San Andreas Fault Zone, the Pacific-North American plate boundary. Geomorphologic expression and surface processes associated with the QCFZ system have been revealed in unprecedented detail by recent seabed mapping surveys. Convergence of the Pacific and North American plates along northern British Columbia is well known, but how the QCFZ accommodates this convergence is still a subject of controversy. The multibeam sonar bathymetry data reveal, for the first time, evidence of a fault valley with small depressions on the upper slope, offshore central Haida Gwaii (Queen Charlotte Islands). The depressions form where strike-slip right-step offsets have realigned the fault due to oblique convergence. Core stratigraphy and radiocarbon dating of sediments within the fault valley and small depressions suggest that these features are recent in origin. In addition, the development of the fault valley and dislocation of submarine canyons control sediment migration from the continental shelf through to the lower slope. This interpretation of the geomorphic expression of major plate tectonic processes along the QCFZ can now be tested with new surveys subsequent to the October 2012 magnitude 7.7 earthquake.

  7. Sexual response of male Drosophila to honey bee queen mandibular pheromone: implications for genetic studies of social insects.

    Science.gov (United States)

    Croft, Justin R; Liu, Tom; Camiletti, Alison L; Simon, Anne F; Thompson, Graham J

    2017-02-01

    Honey bees secrete a queen mandibular pheromone that renders workers reproductively altruistic and drones sexually attentive. This sex-specific function of QMP may have evolved from a sexually dimorphic signaling mechanism derived from pre-social ancestors. If so, there is potential for pre-social insects to respond to QMP, and in a manner that is comparable to its normal effect on workers and drones. Remarkably, QMP applied to female Drosophila does induce worker-like qualities [Camiletti et al. (Entomol Exp Appl 147:262, 2013)], and we here extend this comparison to examine the effects of bee pheromone on male fruit flies. We find that male Drosophila melanogaster consistently orient towards a source of queen pheromone in a T-maze, suggesting a recruitment response comparable to the pheromone's normal effect on drones. Moreover, exposure to QMP renders male flies more sexually attentive; they display intensified pre-copulatory behavior towards conspecific females. We can inhibit this sexual effect through a loss-of-olfactory-function mutation, which suggests that the pheromone-responsive behavioral mechanism is olfactory-driven. These pheromone-induced changes to male Drosophila behavior suggest that aspects of sexual signaling are conserved between these two distantly related taxa. Our results highlight a role for Drosophila as a genetically tractable pre-social model for studies of social insect biology.

  8. An investigation of sea ice motion and fluxes within the Prince Gustaf Adolf Sea, Queen Elizabeth Islands, Canada, 2010

    Science.gov (United States)

    Wohlleben, T.; Howell, S.; Agnew, T.; Komarov, A. S.

    2011-12-01

    In this study, the sea ice flux events that occurred through the Prince Gustaf Adolf Sea flux gate into the Queen Elizabeth Islands (QEI) over the 2010 season are investigated in detail. In the Canadian Arctic Archipelago, multi-year ice (MYI) exports and in situ summer melt are primarily balanced by MYI influx events into QEI during the brief period each year when ice exchanges freely between the Arctic Ocean and the QEI reservoir. Here, data from two Canadian Ice Service satellite tracking beacons that drifted through the Gustaf flux gate in 2010, along with atmospheric sea level pressure and wind data, are compared to ice drift velocities derived from RADARSAT imagery using a new sea ice tracking system. It is demonstrated in this study that the annual average ice drifts implied by the fluxes reported in previous works underestimate the basic current-driven flow of sea ice across the Prince Gustaf Adolf Sea gate (as determined from Radarsat imagery during periods of no wind). It is further established that ice drifts (and hence ice fluxes) through the Gustaf flux gate vary spatially, with velocities on the eastern side in 2010 being consistently greater than those on the western side by a factor of ~2. These results reveal the potential of using Radarsat-derived ice motion to expand upon and improve the limited data on ocean currents within the Queen Elizabeth Islands, as well as to refine estimates of ice flux magnitudes and spatial patterns in this area.

  9. Arbitrators, Blacks and Discipline

    Science.gov (United States)

    Jennings, Kenneth

    1975-01-01

    A discussion of the handling of disciplinary problems of black employees concludes that management should be concerned because of the effect that grievance resolution may have on the company's overall employee discipline program and the additional appeal alternatives available to the black employee. (Author/EA)

  10. Perturbing supersymmetric black hole

    CERN Document Server

    Onozawa, H; Mishima, T; Ishihara, H; Onozawa, Hisashi; Okamura, Takashi; Mishima, Takashi; Ishihara, Hideki

    1996-01-01

    An investigation of the perturbations of the Reissner-Nordstr\\"{o}m black hole in the N=2 supergravity is presented. In the extreme case, the black hole responds to the perturbation of each field in the same manner. This is possibly because we can match the modes of the graviton, gravitino, and photon using supersymmetry transformations.

  11. Black Hole Dynamic Potentials

    Indian Academy of Sciences (India)

    Koustubh Ajit Kabe

    2012-09-01

    In the following paper, certain black hole dynamic potentials have been developed definitively on the lines of classical thermodynamics. These potentials have been refined in view of the small differences in the equations of the laws of black hole dynamics as given by Bekenstein and those of thermodynamics. Nine fundamental black hole dynamical relations have been developed akin to the four fundamental thermodynamic relations of Maxwell. The specific heats , and , have been defined. For a black hole, these quantities are negative. The d equation has been obtained as an application of these fundamental relations. Time reversible processes observing constancy of surface gravity are considered and an equation connecting the internal energy of the black hole , the additional available energy defined as the first free energy function , and the surface gravity , has been obtained. Finally as a further application of the fundamental relations, it has been proved for a homogeneous gravitational field in black hole space times or a de Sitter black hole that $C_{\\Omega,\\Phi}-C_{J,Q}=\\kappa \\left[\\left(\\dfrac{\\partial J}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial \\Omega}{\\partial \\kappa}\\right)_{J,Q}+\\left(\\dfrac{\\partial Q}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial\\Phi}{\\partial \\kappa}\\right)_{J,Q}\\right]$. This is dubbed as the homogeneous fluid approximation in context of the black holes.

  12. Black holes matter

    DEFF Research Database (Denmark)

    Kragh, Helge Stjernholm

    2016-01-01

    Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015).......Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015)....

  13. Scattering by Black Holes

    CERN Document Server

    Andersson, N

    2000-01-01

    This is a chapter on Black-hole Scattering that was commissioned for an Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by Academic Press. The chapter surveys wave propagation in black-hole spacetimes, diffraction effects in wave scattering, resonances, quasinormal modes and related topics.

  14. Blacks and Trade Unionism

    Science.gov (United States)

    Ashenfelter, Orley

    1975-01-01

    This testimony, before a public hearing of the New York City Commission on Human Rights in May 1974, focuses on two issues: (1) the effect of the presence of trade unionism on the position of black workers in the labor market relative to white workers; and (2) the effect of federal government efforts to increase the position of black workers…

  15. Fifty shades of black

    Science.gov (United States)

    Cartwright, Jon

    2015-11-01

    Creating dark materials that prevent reflections has become hot competition recently, with Guinness World Records having to keep revising the darkest substance yet created. But depending on who's asking, the best black may not be the blackest black, as Jon Cartwright discovers.

  16. Cosmological Black Holes

    CERN Document Server

    Stornaiolo, C

    2002-01-01

    In this letter we propose the existence of low density black holes and discuss its compatibility with the cosmological observations. The origin of these black holes can be traced back to the collapse of long wavelength cosmological perturbations during the matter dominated era, when the densities are low enough to neglect any internal and thermal pressure. By introducing a threshold density $\\hat{\\rho}$ above which pressure and non-gravitational interactions become effective, we find the highest wavelength for the perturbations that can reach an equilibrium state instead of collapsing to a black hole. The low density black holes introduced here, if they exist, can be observed through weak and strong gravitational lensing effects. Finally we observe that we obtained here a cosmological model which is capable to explain in a qualitative way the void formation together with the value $\\Omega=1$. But we remark that it needs to be improved by considering non spherical symmetric black holes.

  17. Primordial Black Hole Baryogenesis

    CERN Document Server

    Baumann, D; Turok, N G; Baumann, Daniel; Steinhardt, Paul J.; Turok, Neil

    2007-01-01

    We reconsider the possibility that the observed baryon asymmetry was generated by the evaporation of primordial black holes that dominated the early universe. We present a simple derivation showing that the baryon asymmetry is insensitive to the initial black hole density and the cosmological model but is sensitive to the temperature-dependence of the CP and baryon-violating (or lepton-violating) interactions. We also consider the possibility that black holes stop evaporating and form Planck-mass remnants that act as dark matter. We show that primordial black holes cannot simultaneously account for both the observed baryon asymmetry and the (remnant) dark matter density unless the magnitude of CP violation is much greater than expected from most particle physics models. Finally, we apply these results to ekpyrotic/cyclic models, in which primordial black holes may form when branes collide. We find that obtaining the observed baryon asymmetry is compatible with the other known constraints on parameters.

  18. Lifshitz Topological Black Holes

    CERN Document Server

    Mann, R B

    2009-01-01

    I find a class of black hole solutions to a (3+1) dimensional theory gravity coupled to abelian gauge fields with negative cosmological constant that has been proposed as the dual theory to a Lifshitz theory describing critical phenomena in (2+1) dimensions. These black holes are all asymptotic to a Lifshitz fixed point geometry and depend on a single parameter that determines both their area (or size) and their charge. Most of the solutions are obtained numerically, but an exact solution is also obtained for a particular value of this parameter. The thermodynamic behaviour of large black holes is almost the same regardless of genus, but differs considerably for small black holes. Screening behaviour is exhibited in the dual theory for any genus, but the critical length at which it sets in is genus-dependent for small black holes.

  19. TiO2/Chitosan-NH4I(+I2-BMII-Based Dye-Sensitized Solar Cells with Anthocyanin Dyes Extracted from Black Rice and Red Cabbage

    Directory of Open Access Journals (Sweden)

    M. H. Buraidah

    2011-01-01

    Full Text Available Dye sensitized solar cells (DSSCs were fabricated using anthocyanin dye and polymer electrolyte with ammonium iodide (NH4I salt. The study was designed to focus on increasing the efficiency of the DSSC. DSSC using 26.9 wt. % chitosan-22 wt. % NH4I(+2.2 wt.% I2-48.9 wt. % IL solid electrolyte, black rice anthocyanin with Pt counter electrode showed Jsc of 172 μA cm−2 and Voc of 195 mV. The performance of the cell with Pt electrode was further improved by coating a blocking layer on the indium tin oxide (ITO substrate. The black rice DSSC using 11 wt. % (chitosan:PEO, wt. ratio 30:70-9 wt. % NH4I-80 wt. % BMII gel electrolyte exhibited Jsc of 1213 μA cm−2, Voc of 400 mV, FF of 0.47, and η of 0.23%. The red cabbage anthocyanin DSSC containing (phthaloyl chitosan-PEO-NH4I-BMII gel electrolyte using tartaric acid to adjust the pH of anthocyanin solution showed the best performance with the fill factor of 0.39, Jsc of 3503 μA cm−2, Voc of 340 mV, and an overall conversion efficiency of 0.46%.

  20. Black Hole Critical Phenomena Without Black Holes

    CERN Document Server

    Liebling, S L

    2000-01-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  1. Use of carbon filaments in place of carbon black as the current collector of a lithium cell with a thionyl chloride bromine chloride catholyte

    Science.gov (United States)

    Frysz, Christine A.; Shui, Xiaoping; Chung, D. D. L.

    Submicron carbon filaments (ADNH, Applied Sciences Inc.) used in place of carbon black as porous reduction electrodes (i.e., current collectors) in plate and jellyroll configurations in carbon limited lithium batteries with the BCX (bromine chloride in thionyl chloride) catholyte gave a specific capacity (at 2 V cut-off) of up to 8700 mAh/g of carbon, compared with a value of up to 2900 mAh/g of carbon for carbon black. The high specific capacity for the filament electrode is partly due to the filaments' processability into sheets as thin as 0.2 mm with good porosity, acceptable mechanical properties and without binder, and partly due to the high catholyte absorptivity and high rate of catholyte absorption of the filament electrode. Use of solvent-cleansed filaments in place of as-received filaments in making electrodes increased the packing density, thus decreasing capacity per g of carbon. The BCX catholyte acted as a cleanser anyway, due to the thionyl chloride in it. The specific capacity per cm 3 of carbon and that per unit density of carbon were also increased by using carbon filaments in place of carbon black, provided that the filament electrode was not pressed after forming by slurry filtration. Though no binder was needed for the filament plate electrode, it was needed for the filament jellyroll electrode. The Teflon™ binder increased the tensile strength and modulus, but decreased the catholyte absorption and rate of absorption. The filament electrode exhibited 405 less volume electrical resistivity than the carbon black electrode, both without a binder.

  2. On the Charter Question: Black Marxism and Black Nationalism

    Science.gov (United States)

    Stern, Mark; Hussain, Khuram

    2015-01-01

    This article brings two black intellectual traditions to bear on the question of charter schools: black Marxism and black nationalism. The authors examine the theoretical and rhetorical devices used to talk about charters schools by focusing on how notions of "black liberation" are deployed by the charter movement, and to what end. The…

  3. Unrecognized circulation of SAT 1 foot-and-mouth disease virus in cattle herds around Queen Elizabeth National Park in Uganda

    DEFF Research Database (Denmark)

    Dhikusooka, Moses Tefula; Ayebazibwe, Chrisostom; Namatovu, Alice

    2016-01-01

    understand the epidemiology of FMD at the livestock-wildlife-interface, samples were collected from young, unvaccinated cattle from 24 pastoral herds that closely interact with wildlife around Queen Elizabeth National Park in Uganda, and analysed for evidence of FMDV infection. In total, 37 (15 %) of 247...

  4. Identification, expression, and immuno-reactivity of Sol i 2 & Sol i 4 venom proteins of queen red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae).

    Science.gov (United States)

    Lockwood, Stephanie A; Haghipour-Peasley, Jilla; Hoffman, Donald R; Deslippe, Richard J

    2012-10-01

    We report on two low-molecular weight proteins that are stored in the venom of queen red imported fire ants (Solenopsis invicta). Translated amino acid sequences identified one protein to have 74.8% identity with the Sol i 2w worker allergen, and the other protein was found to have 96/97% identity with Sol i 4.01w/4.02w worker allergens. Both Sol i 2 and Sol i 4 queen and worker proteins were expressed using pEXP1-DEST vector in SHuffle™ T7 Express lysY Escherichia coli. Proteins were expressed at significant concentrations, as opposed to the μg/ml amounts by our previous expression methods, enabling further study of these proteins. Sol i 2q protein bound weakly to human IgE, sera pooled from allergic patients, whereas Sol i 2w, Sol i 4.01w, and Sol i 4q proteins bound strongly. Despite Sol i 2w and Sol i 2q proteins having 74.8% identity, the queen protein is less immuno-reactive than the worker allergen. This finding is consistent with allergic individuals being less sensitive to queen than worker venom.

  5. Effects of juvenile hormone and ecdysone on the timing of vitellogenin appearance in hemolymph of queen and worker pupae of Apis mellifera

    Directory of Open Access Journals (Sweden)

    Angel Roberto Barchuk

    2002-01-01

    Full Text Available The caste-specific regulation of vitellogenin synthesis in the honeybee represents a problem with many yet unresolved details. We carried out experiments to determine when levels of vitellogenin are first detected in hemolymph of female castes of Apis mellifera, and whether juvenile hormone and ecdysteroids modulate this process. Vitellogenin levels were measured in hemolymph using immunological techniques. We show that in both castes the appearance of vitellogenin in the hemolymph occurs during the pupal period, but the timing was different in the queen and worker. Vitellogenin appears in queens during an early phase of cuticle pigmentation approximately 60h before eclosion, while in workers the appearance of vitellogenin is more delayed, initiating in the pharate adult stage, approximately 10h before eclosion. The timing of vitellogenin appearance in both castes coincides with a slight increase in endogenous levels of juvenile hormone that occurs at the end of pupal development. The correlation between these events was corroborated by topical application of juvenile hormone. Exogenous juvenile hormone advanced the timing of vitellogenin appearance in both castes, but caste-specific differences in timing were maintained. Injection of actinomycin D prevented the response to juvenile hormone. In contrast, queen and worker pupae that were treated with ecdysone showed a delay in the appearance of vitellogenin. These data suggest that queens and workers share a common control mechanism for the timing of vitellogenin synthesis, involving an increase in juvenile hormone titers in the presence of low levels of ecdysteroids.

  6. Queen Nefertari, the Royal Spouse of Pharaoh Ramses II: A Multidisciplinary Investigation of the Mummified Remains Found in Her Tomb (QV66)

    Science.gov (United States)

    Habicht, Michael E.; Bianucci, Raffaella; Buckley, Stephen A.; Fletcher, Joann; Bouwman, Abigail S.; Öhrström, Lena M.; Seiler, Roger; Galassi, Francesco M.; Hajdas, Irka; Vassilika, Eleni; Böni, Thomas; Henneberg, Maciej; Rühli, Frank J.

    2016-01-01

    Queen Nefertari, the favourite Royal Consort of Pharaoh Ramses II (Ancient Egypt, New Kingdom, 19th Dynasty c. 1250 BC) is famous for her beautifully decorated tomb in the Valley of the Queens. Her burial was plundered in ancient times yet still many objects were found broken in the debris when the tomb was excavated. Amongst the found objects was a pair of mummified legs. They came to the Egyptian Museum in Turin and are henceforth regarded as the remains of this famous Queen, although they were never scientifically investigated. The following multidisciplinary investigation is the first ever performed on those remains. The results (radiocarbon dating, anthropology, paleopathology, genetics, chemistry and Egyptology) all strongly speak in favour of an identification of the remains as Nefertari’s, although different explanations—albeit less likely—are considered and discussed. The legs probably belong to a lady, a fully adult individual, of about 40 years of age. The materials used for embalming are consistent with Ramesside mummification traditions and indeed all objects within the tomb robustly support the burial as of Queen Nefertari. PMID:27902731

  7. Transcript levels of ten caste-related genes in adult diploid males of Melipona quadrifasciata (Hymenoptera, Apidae: a comparison with haploid males, queens and workers

    Directory of Open Access Journals (Sweden)

    Andreia A. Borges

    2011-01-01

    Full Text Available In Hymenoptera, homozygosity at the sex locus results in the production of diploid males. In social species, these pose a double burden by having low fitness and drawing resources normally spent for increasing the work force of a colony. Yet, diploid males are of academic interest as they can elucidate effects of ploidy (normal males are haploid, whereas the female castes, the queens and workers, are diploid on morphology and life history. Herein we investigated expression levels of ten caste-related genes in the stingless bee Melipona quadrifasciata, comparing newly emerged and 5-day-old diploid males with haploid males, queens and workers. In diploid males, transcript levels for dunce and paramyosin were increased during the first five days of adult life, while those for diacylglycerol kinase and the transcriptional co-repressor groucho diminished. Two general trends were apparent, (i gene expression patterns in diploid males were overall more similar to haploid ones and workers than to queens, and (ii in queens and workers, more genes were up-regulated after emergence until day five, whereas in diploid and especially so in haploid males more genes were down-regulated. This difference between the sexes may be related to longevity, which is much longer in females than in males.

  8. Queen conch (Strombus gigas testis regresses during the reproductive season at nearshore sites in the Florida Keys.

    Directory of Open Access Journals (Sweden)

    Daniel J Spade

    Full Text Available BACKGROUND: Queen conch (Strombus gigas reproduction is inhibited in nearshore areas of the Florida Keys, relative to the offshore environment where conchs reproduce successfully. Nearshore reproductive failure is possibly a result of exposure to environmental factors, including heavy metals, which are likely to accumulate close to shore. Metals such as Cu and Zn are detrimental to reproduction in many mollusks. METHODOLOGY/PRINCIPAL FINDINGS: Histology shows gonadal atrophy in nearshore conchs as compared to reproductively healthy offshore conchs. In order to determine molecular mechanisms leading to tissue changes and reproductive failure, a microarray was developed. A normalized cDNA library for queen conch was constructed and sequenced using the 454 Life Sciences GS-FLX pyrosequencer, producing 27,723 assembled contigs and 7,740 annotated transcript sequences. The resulting sequences were used to design the microarray. Microarray analysis of conch testis indicated differential regulation of 255 genes (p<0.01 in nearshore conch, relative to offshore. Changes in expression for three of four transcripts of interest were confirmed using real-time reverse transcription polymerase chain reaction. Gene Ontology enrichment analysis indicated changes in biological processes: respiratory chain (GO:0015992, spermatogenesis (GO:0007283, small GTPase-mediated signal transduction (GO:0007264, and others. Inductively coupled plasma-mass spectrometry analysis indicated that Zn and possibly Cu were elevated in some nearshore conch tissues. CONCLUSIONS/SIGNIFICANCE: Congruence between testis histology and microarray data suggests that nearshore conch testes regress during the reproductive season, while offshore conch testes develop normally. Possible mechanisms underlying the testis regression observed in queen conch in the nearshore Florida Keys include a disruption of small GTPase (Ras-mediated signaling in testis development. Additionally, elevated tissue

  9. Black holes new horizons

    CERN Document Server

    Hayward, Sean Alan

    2013-01-01

    Black holes, once just fascinating theoretical predictions of how gravity warps space-time according to Einstein's theory, are now generally accepted as astrophysical realities, formed by post-supernova collapse, or as supermassive black holes mysteriously found at the cores of most galaxies, powering active galactic nuclei, the most powerful objects in the universe. Theoretical understanding has progressed in recent decades with a wider realization that local concepts should characterize black holes, rather than the global concepts found in textbooks. In particular, notions such as trapping h

  10. Scalarized hairy black holes

    Energy Technology Data Exchange (ETDEWEB)

    Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kunz, Jutta [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Yazadjiev, Stoytcho [Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria)

    2015-05-11

    In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  11. Scalarized hairy black holes

    Directory of Open Access Journals (Sweden)

    Burkhard Kleihaus

    2015-05-01

    Full Text Available In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  12. Black Hole Entropy

    OpenAIRE

    P. Mitra

    1994-01-01

    In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy $S^{BH}$ (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy $S^{SM}=-\\mbox{Tr}(\\hat{\\rho}\\ln \\hat{\\rho})$ (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (...

  13. Black hole entropy

    CERN Document Server

    Frolov, V

    1994-01-01

    In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy S^{BH} (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy S^{SM}=-\\mbox{Tr}(\\hat{\\rho}\\ln \\hat{\\rho}) (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (i.e. its independence of the number and properties of the fields which might contribute to S^{SM}) is given.

  14. Primordial Black Holes

    CERN Document Server

    MacGibbon, Jane H; Linnemann, J T; Marinelli, S S; Stump, D; Tollefson, K

    2015-01-01

    Primordial Black Holes (PBHs) are of interest in many cosmological contexts. PBHs lighter than about 1012 kg are predicted to be directly detectable by their Hawking radiation. This radiation should produce both a diffuse extragalactic gamma-ray background from the cosmologically-averaged distribution of PBHs and gamma-ray burst signals from individual light black holes. The Fermi, Milagro, Veritas, HESS and HAWC observatories, in combination with new burst recognition methodologies, offer the greatest sensitivity for the detection of such black holes or placing limits on their existence.

  15. Feminism and Black Women's Studies.

    Science.gov (United States)

    Hooks, Bell

    1989-01-01

    Women's studies programs have largely ignored Black women. Until Black women's studies courses are developed, feminist scholarship on Black women will not advance, and the contributions of Black women to women's rights movements and African American literature and scholarship may be neglected. (DM)

  16. The Price of "Black Dominance."

    Science.gov (United States)

    Hoberman, John

    2000-01-01

    Discusses the harmful effects of stereotyping black males as athletes, noting that over-identification with athletes and the world of physical performance limits black children's development by discouraging academic achievement. Examines the negative influence of mass media focus on black athletes, rappers, and stylized ghetto blackness. Discusses…

  17. Thymoquinone from nutraceutical black cumin oil activates Neu4 sialidase in live macrophage, dendritic, and normal and type I sialidosis human fibroblast cells via GPCR Galphai proteins and matrix metalloproteinase-9.

    Science.gov (United States)

    Finlay, Trisha M; Jayanth, Preethi; Amith, Schammim Ray; Gilmour, Alanna; Guzzo, Christina; Gee, Katrina; Beyaert, Rudi; Szewczuk, Myron R

    2010-04-01

    Anti-inflammatory activities of thymoquinone (TQ) have been demonstrated in in vitro and in vivo studies. However, the precise mechanism(s) of TQ in these anti-inflammatory activities is not well understood. Using a newly developed assay to detect sialidase activity in live macrophage cells (Glycoconj J doi: 10.1007/s10719-009-9239-8 ), here we show that TQ has no inhibitory effect on endotoxin lipopolysaccharide (LPS) induced sialidase activity in live BMC-2 macrophage cells. In contrast, the parent black seed oil (BSO) and another constituent of BSO para-cymene (p-CY) completely block LPS induced sialidase activity. All of these compounds had no effect on cell viability. On the other hand, TQ induces a vigorous sialidase activity in live BMC-2 macrophage cells in a dose dependent manner as well in live DC-2.4 dendritic cells, HEK-TLR4/MD2, HEK293, SP1 mammary adenocarcinoma cells, human WT and 1140F01 and WG0544 type I sialidosis fibroblast cells. Tamiflu (oseltamivir phosphate) inhibits TQ-induced sialidase activity in live BMC-2 cells with an IC(50) of 0.0194 microM compared to an IC(50) of 19.1 microM for neuraminidase inhibitor DANA (2-deoxy-2,3-dehydro-N-acetylneuraminic acid). Anti-Neu1, -2 and -3 antibodies have no inhibition of TQ-induced sialidase activity in live BMC-2 and human THP-1 macrophage cells but anti-Neu4 antibodies completely block this activity. There is a vigorous sialidase activity associated with TQ treated live primary bone marrow (BM) macrophage cells derived from WT and hypomorphic cathepsin A mice with a secondary Neu1 deficiency (NeuI KD), but not from Neu4 knockout (Neu4 KO) mice. Pertussis toxin (PTX), a specific inhibitor of Galphai proteins of G-protein coupled receptor (GPCR) and the broad range inhibitors of matrix metalloproteinase (MMP) galardin and piperazine applied to live BMC-2, THP-1 and primary BM macrophage cells completely block TQ-induced sialidase activity. These same inhibitory effects are not observed with the GM1

  18. Black Teenage Pregnancy

    Directory of Open Access Journals (Sweden)

    Loretta I. Winters

    2012-01-01

    Full Text Available This article examines the relative importance of race and socioeconomic status (SES in determining whether Black and White teenagers report having ever been pregnant. Data gathered from 1999 to 2006 by the National Center for Health Statistics of the Center for Disease Control and Prevention included 1,580 Black and White females aged 15 to 19 years. Results supported the effects of race and SES, with SES having the stronger effect. However, the effects of race and SES differ when controlling for the state of the economy. No difference between Blacks and Whites was found during better economic times. During 2003-2004, the period of greatest economic stress, race was determined to be the only predictor of teenage pregnancy. In particular, during 2005-2006, the reduction in pregnancy rates for Black minors (15-17 fell below those for White minors within their respective SES categories. Policy implications are discussed in light of these findings.

  19. Janus black holes

    Science.gov (United States)

    Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.

    2011-10-01

    In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.

  20. Black Rail Pilot Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Aural surveys using tape recorded calls proved to be an efficient and effective way to survey large expanses of shallow marsh for black rails (Laterallus...

  1. Black Friday = Broget Branding?

    DEFF Research Database (Denmark)

    Hansen, Heidi

    2015-01-01

    Black Friday er et godt eksempel på, hvordan ikke kun produktbrands og corporate brands rejser på tværs af landegrænser, men også traditioner som Halloween, Valentines Day og i dette tilfælde den ultimative tilbuds-fredag, som i USA går under navnet Black Friday. Men hvad er Black Friday i Danmark......? Essensen ved Black Friday er lave priser, og det er der ved første øjekast ikke mange brandingmuligheder forbundet ved, hvis man forstår branding som en måde at skabe ekstra værdi omkring sit produkt eller sin virksomhed. Som brand bliver man dog alligevel nødt til at forholde sig til konceptet, da det er...

  2. Modelling quantum black hole

    CERN Document Server

    Govindarajan, T R

    2016-01-01

    Novel bound states are obtained for manifolds with singular potentials. These singular potentials require proper boundary conditions across boundaries. The number of bound states match nicely with what we would expect for black holes. Also they serve to model membrane mechanism for the black hole horizons in simpler contexts. The singular potentials can also mimic expanding boundaries elegantly, there by obtaining appropriately tuned radiation rates.

  3. Helical superconducting black holes.

    Science.gov (United States)

    Donos, Aristomenis; Gauntlett, Jerome P

    2012-05-25

    We construct novel static, asymptotically five-dimensional anti-de Sitter black hole solutions with Bianchi type-VII(0) symmetry that are holographically dual to superconducting phases in four spacetime dimensions with a helical p-wave order. We calculate the precise temperature dependence of the pitch of the helical order. At zero temperature the black holes have a vanishing entropy and approach domain wall solutions that reveal homogenous, nonisotropic dual ground states with an emergent scaling symmetry.

  4. Black Is Cool!

    Institute of Scientific and Technical Information of China (English)

    Dorine; Houston

    1997-01-01

    Do you remember the colors the college freshmen dyed their hair when you were here? Turquoise, orange, bright yellow.... Things have changed. Black has (?)ome the color of choice among the young people. Young men and women alike dye their hair coal black. The women let their hair grow very long. and it hangs straight and stringy down their backs. The young men leave it long on

  5. Braneworld black holes

    CERN Document Server

    Gregory, Ruth

    2008-01-01

    In these lectures, I give an introduction to and overview of braneworlds and black holes in the context of warped compactifications. I first describe the general paradigm of braneworlds, and introduce the Randall-Sundrum model. I discuss braneworld gravity, both using perturbation theory, and also non perturbative results. I then discuss black holes on the brane, the obstructions to finding exact solutions, and ways of tackling these difficulties. I describe some known solutions, and conclude with some open questions and controversies.

  6. Black Hole Induced Ejections

    OpenAIRE

    Pelletier, G.

    2004-01-01

    Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull astrophysical phenomena such as AGNs, micro- quasars and GRBs where relativistic ejections are observed, are at the heart of high energy a...

  7. Cosmic censorship inside black holes

    CERN Document Server

    Thorlacius, L

    2006-01-01

    A simple argument is given that a traversable Cauchy horizon inside a black hole is incompatible with unitary black hole evolution. The argument assumes the validity of black hole complementarity and applies to a generic black hole carrying angular momentum and/or charge. In the second part of the paper we review recent work on the semiclassical geometry of two-dimensional charged black holes.

  8. 2009 - Black & White - Essex (0.5m)

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VTORTHO_0_5M_PAN_2009 data includes panchromatic (black and white) orthophotography (orthophoto) at 1:5000 scale (0.5 meter cell resolution)....

  9. Re-framing the prostitute identity in Zimbabwe: An approach to Virginia Phiri’s novel Highway queen (2010

    Directory of Open Access Journals (Sweden)

    Oliver Nyambi

    2015-03-01

    Full Text Available In Zimbabwe, as in most traditionally conservative, patriarchal and Christian dominated countries, female sex work is abhorred on moral grounds as an unbecoming means of livelihood which takes away the practising woman’s social respectability. In such societies, then, the moral threat and stigma associated with female sex work affect women’s decisions on whether or not to take up sex work as a permanent means of livelihood. One can, however, ask how sustainable and stable these patriarchally constructed notions of morality and female identity are, especially in the face of crises? This article uses Virginia Phiri’s novel Highway queen, which is set in one of Zimbabwe’s economically tumultuous eras, to demonstrate how cultural texts grapple with the discourse of female sex work in contemporary Zimbabwe. The gist of my argument is that dominant prostitute identity constructs shaped by Zimbabwe’s patriarchal social and economic system are unstable. I find that the novel Highway queen manipulates such instability not only to re-inscribe sex work as a product of patriarchal impairment of female agency but, perhaps more importantly, to reflect on how women who are forced by circumstances to become sex workers can rise above their passive victimhood to achieve personal goals despite the social odds charted by patriarchy. Zooming in on the representation of the daily experiences of the female sex worker and protagonist, Sophie, the article explores the various ways in which the novel deconstructs stereotypical perceptions of female sex work and sex workers. The analysis ends with the argument that, whilst Sophie’s situation is fundamentally tragic, it affectively appeals to our sense of morality in a way which destabilises dominant (patriarchal constructs of sex work.

  10. Meu nome é “Híbrida”: Corpo, gênero e sexualidade na experiência drag queen

    Directory of Open Access Journals (Sweden)

    Joseylson Fagner dos Santos

    2012-08-01

    Full Text Available Homem e mulher, feminino e masculino: o comportamento social dos indivíduos é norteado por dicotomias que encontramos em corpos aprendidos e disciplinados. Nesse sentido, os papéis sociais de gênero vêm a ser fatores de diferenciação sexual, de forma a orientar a inteligibilidade dos corpos, através construções sociais de códigos estéticos, funcionais e comportamentais. A drag queen – representada como um corpo onde os papéis sociais de gênero encontram-se justapostos – apresenta, através da performance, a possibilidade de ressignificar as relações fixas entre gênero, corpo e sexo. Enquanto indivíduo que opera na transformação estética e comportamental de seus papéis de gênero, a drag permite pensar numa desnaturalização dos laços que envolvem esses conceitos. Diferente do travesti e do transexual, a drag queen questiona a fixidez de questões “hetero-normativas” através de um ato performativo, onde o corpo adquire signos específicos do sexo feminino e aplica a um corpo masculino, tornando-se “queer”. A experiência do corpo drag representa uma possibilidade de verificar o momento em que a normatividade da relação entre corpo, sexo e gênero entra em desconstrução, resultando num corpo híbrido. O artigo se propõe à reflexão sobre a formação da dicotomia masculino/feminino e a produção performativa de corpos drag.

  11. Black hole critical phenomena without black holes

    Indian Academy of Sciences (India)

    Steven L Liebling

    2000-10-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  12. Charged Galileon black holes

    Science.gov (United States)

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  13. Ultramassive Black Hole Coalescence

    CERN Document Server

    Khan, Fazeel; Berczik, Peter

    2015-01-01

    Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gr...

  14. Aflatoxins in black tea in Iran.

    Science.gov (United States)

    Pouretedal, Zohreh; Mazaheri, Mansooreh

    2013-01-01

    Aflatoxins (AFs) are highly toxic, and carcinogenic secondary fungal metabolites and have been detected in various food commodities. In this regard, 40 black tea samples including domestic and imported black tea were analysed for aflatoxin contamination by high-performance liquid chromatography using a post-column derivatisation procedure (Kobra cell) with fluorescence detection. Samples were randomly collected in 2010 from Tehran markets. The results revealed that 30 among 40 samples were contaminated with aflatoxins (27.5% of the total). Mean AFB1 content was 10.0 ng/g and mean of aflatoxin total was 12.07 ng/g for the 11 contaminated samples.

  15. Black holes and beyond

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-02-01

    Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for

  16. Thermodynamic black di-rings

    CERN Document Server

    Iguchi, Hideo

    2010-01-01

    Previously the five dimensional $S^1$-rotating black rings have been superposed in concentric way by some solitonic methods and regular systems of two $S^1$-rotating black rings were constructed by the authors and then Evslin and Krishnan (we called these solutions black di-rings). In this place we show some characteristics of the solutions of five dimensional black di-rings, especially in thermodynamic equilibrium. After the summary of the di-ring expressions and their physical quantities, first we comment on the equivalence of the two different solution-sets of the black di-rings. Then the existence of thermodynamic black di-rings are shown, in which both iso-thermality and iso-rotation between the inner black ring and the outer black ring are realized. We also give detailed analysis of peculiar properties of the thermodynamic black di-ring including discussion about a certain kind of thermodynamic stability (instability) of the system.

  17. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2009-05-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  18. Charged Galileon black holes

    CERN Document Server

    Babichev, Eugeny; Hassaine, Mokhtar

    2015-01-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematic...

  19. Black Afrikaans: An alternative use

    Directory of Open Access Journals (Sweden)

    Anna P. Maritz

    2016-09-01

    Full Text Available This article provides a first look at the nature of the alternative functions of Black Afrikaans. These functions realise when Black Afrikaans is imitated by Afrikaans mother-tongue speakers. The functions of the alternative use of Black Afrikaans centre on: the social nature of the variety, sensitivity as a deciding role-player, identity, humour, inclusivity and exclusivity, language repertoire and similar variety. Furthermore, because of the direct relationship between Black Afrikaans, Pidginised Afrikaans and the imitation of Black Afrikaans, these varieties are compared to establish a starting point description for the imitation of Black Afrikaans, as the variety has not yet been described.

  20. Black Hole Induced Ejections

    CERN Document Server

    Pelletier, G

    2004-01-01

    Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull astrophysical phenomena such as AGNs, micro- quasars and GRBs where relativistic ejections are observed, are at the heart of high energy astrophysics. The combination of General Relativity and Magneto-HydroDynamics (MHD) makes theory difficult; however great pionneers opened beautiful tracks in the seventies and left important problems to be solved for the next decades. These lectures will present the status of these issues. They have a tutorial aspect together with critical review aspect and contain also some new issues. Most of these lectures has been presented at the "School on Black Hole in the Universe" at Cargese, in May 2003.

  1. Turbulent black holes.

    Science.gov (United States)

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  2. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  3. Black hole entropy quantization

    CERN Document Server

    Corichi, A; Fernandez-Borja, E; Corichi, Alejandro; Diaz-Polo, Jacobo; Fernandez-Borja, Enrique

    2006-01-01

    Ever since the pioneer works of Bekenstein and Hawking, black hole entropy has been known to have a quantum origin. Furthermore, it has long been argued by Bekenstein that entropy should be quantized in discrete (equidistant) steps given its identification with horizon area in (semi-)classical general relativity and the properties of area as an adiabatic invariant. This lead to the suggestion that black hole area should also be quantized in equidistant steps to account for the discrete black hole entropy. Here we shall show that loop quantum gravity, in which area is not quantized in equidistant steps can nevertheless be consistent with Bekenstein's equidistant entropy proposal in a subtle way. For that we perform a detailed analysis of the number of microstates compatible with a given area and show that an observed oscillatory behavior in the entropy-area relation, when properly interpreted yields an entropy that has discrete, equidistant values that are consistent with the Bekenstein framework.

  4. Black hole accretion discs

    CERN Document Server

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. outbursting black-hole low-mass X-ray binaries. We then turn to the role of advection in accretion flow onto black holes illustrating its action and importance with a toy model describing both ADAFs and slim discs. We conclude with a presentation of the general-relativistic formalism describing accretion discs in the Kerr space-time.

  5. Tunneling Through Black Rings

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liu

    2007-01-01

    Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzed by use of the Parikh-Wilczek tunneling method. To get the correct tunneling amplitude and emission rate, we adopt and develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronic discharge all at once, and the effect of back reaction is also taken into account. This constitutes a unified approach to the tunneling problem. Provided the first law of thermodynamics for black rings holds, the emission rate is proportional to the exponential of the change of Bekenstein-Hawking entropy. Explicit calculation for black ring temperatures agrees exactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

  6. Black hole gravitohydromagnetics

    CERN Document Server

    Punsly, Brian

    2008-01-01

    Black hole gravitohydromagnetics (GHM) is developed from the rudiments to the frontiers of research in this book. GHM describes plasma interactions that combine the effects of gravity and a strong magnetic field, in the vicinity (ergosphere) of a rapidly rotating black hole. This topic was created in response to the astrophysical quest to understand the central engines of radio loud extragalactic radio sources. The theory describes a "torsional tug of war" between rotating ergospheric plasma and the distant asymptotic plasma that extracts the rotational inertia of the black hole. The recoil from the struggle between electromagnetic and gravitational forces near the event horizon is manifested as a powerful pair of magnetized particle beams (jets) that are ejected at nearly the speed of light. These bipolar jets feed large-scale magnetized plasmoids on scales as large as millions of light years (the radio lobes of extragalactic radio sources). This interaction can initiate jets that transport energy fluxes exc...

  7. The closest black holes

    CERN Document Server

    Fender, Rob; Heywood, Ian

    2013-01-01

    Starting from the assumption that there is a large population (> 10^8) of isolated, stellar-mass black holes (IBH) distributed throughout our galaxy, we consider the detectable signatures of accretion from the interstellar medium (ISM) that may be associated with such a population. We simulate the nearby (radius 250 pc) part of this population, corresponding to the closest ~35 000 black holes, using current best estimates of the mass distribution of stellar mass black holes combined with two models for the velocity distribution of stellar-mass IBH which bracket likely possibilities. We distribute this population of objects appropriately within the different phases of the ISM and calculate the Bondi-Hoyle accretion rate, modified by a further dimensionless efficiency parameter \\lambda. Assuming a simple prescription for radiatively inefficient accretion at low Eddington ratios, we calculate the X-ray luminosity of these objects, and similarly estimate the radio luminosity from relations found empirically for b...

  8. Horndeski black hole geodesics

    CERN Document Server

    Tretyakova, D A

    2016-01-01

    We examine geodesics for the scalar-tensor black holes in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits may not be present within some model parameters range. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations. We also present a new (although very similar to those previously known) solution, which contains the orbits we expect from a compact object, admits regular scalar field at the horizon and and can fit into the known stability criteria.

  9. Are Black Holes Springy?

    CERN Document Server

    Good, Michael R R

    2014-01-01

    A $(3+1)$-dimensional asymptotically flat Kerr black hole angular speed $\\Omega_+$ can be used to define an effective spring constant, $k=m\\Omega_+^2$. Its maximum value is the Schwarzschild surface gravity, $k = \\kappa $, which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: $2\\pi T = \\kappa - k$. Hooke's law, in the extremal limit, provides the force $F = 1/4$, which is consistent with the conjecture of maximum force in general relativity.

  10. Acoustic black holes

    CERN Document Server

    Visser, M

    1999-01-01

    Acoustic propagation in a moving fluid provides a conceptually clean and powerful analogy for understanding black hole physics. As a teaching tool, the analogy is useful for introducing students to both General Relativity and fluid mechanics. As a research tool, the analogy helps clarify what aspects of the physics are kinematics and what aspects are dynamics. In particular, Hawking radiation is a purely kinematical effect, whereas black hole entropy is intrinsically dynamical. Finally, I discuss the fact that with present technology acoustic Hawking radiation is almost experimentally testable.

  11. Superfluid Black Holes

    CERN Document Server

    Hennigar, Robie A; Tjoa, Erickson

    2016-01-01

    We present what we believe is the first example of a "$\\lambda$-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid $^4$He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically AdS hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  12. Superfluid Black Holes.

    Science.gov (United States)

    Hennigar, Robie A; Mann, Robert B; Tjoa, Erickson

    2017-01-13

    We present what we believe is the first example of a "λ-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid ^{4}He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  13. Characterizing Black Hole Mergers

    Science.gov (United States)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  14. Bulletproof Black Man

    DEFF Research Database (Denmark)

    Højer, Henrik

    2016-01-01

    Netflix’ kommende serie om den sorte Marvel-helt Luke Cage lander snart – midt i de aktuelle racekonflikter i USA. I GIF-anatomien "Bulletproof Black Man" sætter Henrik Højer serien ind i dens amerikanske kontekst.......Netflix’ kommende serie om den sorte Marvel-helt Luke Cage lander snart – midt i de aktuelle racekonflikter i USA. I GIF-anatomien "Bulletproof Black Man" sætter Henrik Højer serien ind i dens amerikanske kontekst....

  15. Black Brane World Scenarios

    CERN Document Server

    Moon, S H

    2001-01-01

    We consider a brane world residing in the interior region inside the horizon of extreme black branes. In this picture, the size of the horizon can be interpreted as the compactification size. The large mass hierarchy is simply translated into the large horizon size, which is provided by the magnitude of charges carried by the black branes. Hence, the macroscopic compactification size is a quantity calculable from the microscopic theory which has only one physical scale, and its stabilization is guaranteed from the charge conservation.

  16. Modeling black hole evaporation

    CERN Document Server

    Fabbri, Alessandro

    2005-01-01

    The scope of this book is two-fold: the first part gives a fully detailed and pedagogical presentation of the Hawking effect and its physical implications, and the second discusses the backreaction problem, especially in connection with exactly solvable semiclassical models that describe analytically the black hole evaporation process. The book aims to establish a link between the general relativistic viewpoint on black hole evaporation and the new CFT-type approaches to the subject. The detailed discussion on backreaction effects is also extremely valuable.

  17. Plant extracts of winter savory, purple coneflower, buckwheat and black elder activate PPAR-γ in COS-1 cells but do not lower blood glucose in Db/db mice in vivo.

    Science.gov (United States)

    Schrader, Eva; Wein, Silvia; Kristiansen, Karsten; Christensen, Lars P; Rimbach, Gerald; Wolffram, Siegfried

    2012-12-01

    The aim of this study was to investigate possible blood glucose-lowering effects of plant extracts in vivo for which prior to this a peroxisome proliferator-activated receptor-γ activity in vitro was observed. The ability of extracts of winter savory, purple coneflower, buckwheat and black elder to dose-dependently activate peroxisome proliferator-activated receptor-γ was determined in a reporter gene assay in COS-1 cells. For evaluation of glucose-lowering effects in vivo, db/db mice were fed a diet containing either rosiglitazone (0.02 g/kg diet, positive control) or one of the plant extracts (0.1 and 1 g/kg diet) for four weeks. Apart from glucose, insulin, triacylglycerols, non-esterified fatty acids, cholesterol and adiponectin were determined in plasma. All plant extracts showed a dose-dependent peroxisome proliferator-activated receptor-γ-activating effect in vitro. In db/db mice none of the plant extracts exerted glucose-lowering effects at the used dosages compared to rosiglitazone. Non-esterified fatty acids, triacylglycerols, cholesterol, insulin and adiponectin in plasma were not altered by the plant extracts as well. Although dose-dependent peroxisome proliferator-activated receptor-γ activity could be shown in COS-1 cells, the experiments in db/db mice lacked to confirm any anti-diabetic effect of the plant extracts in vivo and emphasizes the importance of verifying cell culture data using an appropriate in vivo model.

  18. Homage to Rita Levi-Montalcini, the queen of modern neuroscience.

    Science.gov (United States)

    Aloe, Luigi; Chaldakov, George N

    2013-08-01

    The first cell growth factor, nerve growth factor (NGF), was discovered by Rita Levi-Montalcini (RLM) in the early 1950s. Originally identified as neurite outgrowth-stimulating factor, later studies revealed that non-neuronal cells, including immune cells, endothelial cells, cardiomyocytes, pancreatic beta cells, prostate epithelial and adipose tissue cells, were also targets for and/or sources of NGF. Nerve growth factor is well recognised as mediating multiple biological phenomena, ranging from the neurotrophic through immunotrophic and epitheliotrophic to metabotrophic effects. Consequently, NGF and other members of the neurotrophin family are implicated in the pathogenesis of a large spectrum of neuronal and non-neuronal diseases, ranging from Alzheimer's and other neurodegenerative diseases to atherosclerosis and cardiometabolic disorders. Recent studies have demonstrated the therapeutic potentials of NGF in these conditions, including ocular and cutaneous diseases. NGF TrkA receptor antagonists emerged as novel drugs for pain, prostate and breast cancer, melanoma and urinary bladder syndromes. Here, we briefly describe the 'unpredictable' ideogenesis of the discovery of NGF, a eureka in the neuroscience.

  19. Reflections on a Black Mirror

    CERN Document Server

    Good, Michael R R

    2016-01-01

    A black mirror is an accelerated boundary that produces particles in an exact correspondence to an evaporating black hole. We investigate the spectral dynamics of the particle creation during the formation process.

  20. Quantum aspects of black holes

    CERN Document Server

    2015-01-01

    Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.