Distribution by Scientific Domains

Kinds of Moon

  • full moon

  • Terms modified by Moon

  • moon period

  • Selected Abstracts

    The primary cilium as a gravitational force transducer and a regulator of transcriptional noise

    Stephen J. Moorman
    Abstract Circumstantial evidence has suggested that the primary cilium might function as a gravity sensor. Direct evidence of its gravity-sensing function has recently been provided by studies of rohon beard neurons. These neurons showed changes in the variability of gene expression levels that are linked to the cyclic changes in the Earth's gravitational field due to the Sun and Moon. These cyclic changes also cause the tides. Rohon beard neurons, after the primary cilia have been selectively destroyed, no longer show changes in gene expression variability linked to the cyclic changes in Earth's gravitational field. After the neurons regrow their primary cilia, the link between variability in gene expression levels and the Earth's changing gravitational field returns. This suggests two new functions for the primary cilia, detecting the cyclical changes in the Earth's gravitational field and transducing those changes into changes in the variability (stochastic nature) of gene expression. Developmental Dynamics 237:1955,1959, 2008. © 2008 Wiley-Liss, Inc. [source]

    Rational Pricing of Internet Companies Revisited

    FINANCIAL REVIEW, Issue 4 2001
    Eduardo S. Schwartz
    G12 Abstract In this article we expand and improve the Internet company valuation model of Schwartz and Moon (2000) in numerous ways. By using techniques from real options theory and modern capital budgeting, the earlier paper demonstrated that uncertainty about key variables plays a major role in the valuation of high growth Internet companies. Presently, we make the model more realistic by providing for stochastic costs and future financing, and also by including capital expenditures and depreciation in the analysis. Perhaps more importantly, we offer insights into the practical implementation the model. An important challenge to implementing the original model was estimating the various parameters of the model. Here, we improve the procedure by setting the speed of adjustment parameters equal to one another, by tying the implied half-life of the revenue growth process to analyst forecasts, and by inferring the risk-adjustment parameter from the observed beta of the company's stock price. We illustrate these extensions in a valuation of the company eBay. [source]

    A finite element analysis of tidal deformation of the entire earth with a discontinuous outer layer

    H. L. Xing
    SUMMARY Tidal deformation of the Earth is normally calculated using the analytical solution with some simplified assumptions, such as the Earth is a perfect sphere of continuous media. This paper proposes an alternative way, in which the Earth crust is discontinuous along its boundaries, to calculate the tidal deformation using a finite element method. An in-house finite element code is firstly introduced in brief and then extended here to calculate the tidal deformation. The tidal deformation of the Earth due to the Moon was calculated for an geophysical earth model with the discontinuous outer layer and compared with the continuous case. The preliminary results indicate that the discontinuity could have different effects on the tidal deformation in the local zone around the fault, but almost no effects on both the locations far from the fault and the global deformation amplitude of the Earth. The localized deformation amplitude seems to depend much on the relative orientation between the fault strike direction and the loading direction (i.e. the location of the Moon) and the physical property of the fault. [source]

    Flexible Electronics: Fully Flexible Solution-Deposited ZnO Thin-Film Transistors (Adv. Mater.

    ADVANCED MATERIALS, Issue 38 2010
    Solution-processed ,real' flexible ZnO thin-film transistors (TFTs) on plastic substrates are demonstrated on p. 4308 by Jooho Moon and co-workers. The flexible device shows exceptional and unprecedented stability against various stresses such as bending, rolling, wearing, and folding, exhibiting no degradation at tensile strains up to 6.35%. Such solution processable semiconductor devices can be used to realize transparent, flexible electronic devices. [source]

    Heterogeneity and cross section dependence in panel data models: theory and applications introduction

    Badi H. Baltagi
    The papers included in this special issue are primarily concerned with the problem of cross section dependence and heterogeneity in the analysis of panel data models and their relevance in applied econometric research. Cross section dependence can arise due to spatial or spill over effects, or could be due to unobserved (or unobservable) common factors. Much of the recent research on non-stationary panel data have focussed on this problem. It was clear that the first generation panel unit root and cointegration tests developed in the 1990's, which assumed cross-sectional independence, are inadequate and could lead to significant size distortions in the presence of neglected cross-section dependence. Second generation panel unit root and cointegration tests that take account of possible cross-section dependence in the data have been developed, see the recent surveys by Choi (2006) and Breitung and Pesaran (2007). The papers by Baltagi, Bresson and Pirotte, Choi and Chue, Kapetanios, and Pesaran in this special issue are further contributions to this literature. The papers by Fachin, and Moon and Perron are empirical studies in this area. Controlling for heterogeneity has also been an important concern for empirical researchers with panel data methods promising better handle on heterogeneity than cross-section data methods. The papers by Hsiao, Shen, Wang and Weeks, Pedroni and Serlenga and Shin are empirical contributions to this area. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Investigation of hard lubricant coatings in space in orbit around the moon

    V. M. Yarosh
    Abstract This paper reports on friction tests of a hard lubricant coating conducted in orbit around the Moon. The measurements included those taken in terrestrial conditions in a vacuum chamber, at the launch site, and in lunar orbit. The paper includes a description of an autonomous friction simulator that was mounted outside the spacecraft. In this device, two types of friction, ,shaft-bush' and ,disc-indenter', have been tested. For the first time, a long experiment exploring the tribological characteristics of an antifriction coating in a real space environment in a lunar satellite orbit has been carried out. Over a fifteen-month period, the friction units were run in the space environment. These tests indicated a tendency for the friction coefficient to reduce to a limit value in such an orbit and environment. [source]

    Compositional and lithological diversity among brecciated lunar meteorites of intermediate iron concentration

    Randy L. Korotev
    Most have iron concentrations intermediate to those of the numerous feldspathic lunar meteorites (3,7% FeO) and the basaltic lunar meteorites (17,23% FeO). All but one are polymict breccias. Some, as implied by their intermediate composition, are mainly mixtures of brecciated anorthosite and mare basalt, with low concentrations of incompatible elements such as Sm (1,3 ,g/g). These breccias likely originate from points on the Moon where mare basalt has mixed with material of the FHT (Feldspathic Highlands Terrane). Others, however, are not anorthosite-basalt mixtures. Three (17,75 ,/g Sm) consist mainly of nonmare mafic material from the nearside PKT (Procellarum KREEP Terrane) and a few are ternary mixtures of material from the FHT, PKT, and maria. Some contain mafic, nonmare lithologies like anorthositic norites, norites, gabbronorites, and troctolite. These breccias are largely unlike breccias of the Apollo collection in that they are poor in Sm as well as highly feldspathic anorthosite such as that common at the Apollo 16 site. Several have high Th/Sm compared to Apollo breccias. Dhofar 961, which is olivine gabbronoritic and moderately rich in Sm, has lower Eu/Sm than Apollo samples of similar Sm concentration. This difference indicates that the carrier of rare earth elements is not KREEP, as known from the Apollo missions. On the basis of our present knowledge from remote sensing, among lunar meteorites Dhofar 961 is the one most likely to have originated from South Pole-Aitken basin on the lunar far side. [source]

    Lunar dust and lunar simulant activation and monitoring

    William T. WALLACE
    One of the pressing concerns is the effect that lunar dust (the fraction of the lunar regolith <20 ,m in diameter) will have on systems, both human and mechanical, due to the fact that various problems were caused by dust during the Apollo missions. The loss of vacuum integrity in the lunar sample containers during the Apollo era ensured that the present lunar samples are not in the same condition as they were on the Moon; they have been passivated by oxygen and water vapor. To mitigate the harmful effects of lunar dust on humans, methods of "reactivating" the dust must be developed for experimentation, and, ideally, it should be possible to monitor the level of activity to determine methods of deactivating the dust in future lunar habitats. Here we present results demonstrating that simple grinding, as a simple analog to micrometeorite crushing, is apable of substantially activating lunar dust and lunar simulant, and it is possible to determine the level of chemical activity by monitoring the ability of the dust to produce hydroxyl radicals in aqueous solution. Comparisons between ground samples of lunar dust, lunar simulant, and quartz reveal that ground lunar dust is capable of producing over three times the amount of hydroxyl radicals as lunar simulant and an order of magnitude more than ground quartz. [source]

    Ernst Florens Friedrich Chladni (1756,1827) and the origins of modern meteorite research

    Ursula B. Marvin
    These ideas violated two strongly held contemporary beliefs: 1) fragments of rock and metal do not fall from the sky, and 2) no small bodies exist in space beyond the Moon. From the beginning, Chladni was severely criticized for basing his hypotheses on historical eyewitness reports of falls, which others regarded as folk tales, and for taking gross liberties with the laws of physics. Ten years later, the study of fallen stones and irons was established as a valid field of investigation. Today, some scholars credit Chladni with founding meteoritics as a science; others regard his contributions as scarcely worthy of mention. Writings by his contemporaries suggest that Chladni's book alone would not have led to changes of prevailing theories; thus, he narrowly escaped the fate of those scientists who propose valid hypotheses prematurely. However, between 1794 and 1798, four falls of stones were witnessed and widely publicized. There followed a series of epoch-making analyses of fallen stones and "native irons" by the chemist Edward C. Howard and the mineralogist Jacques-Louis de Bournon. They showed that all the stones were much alike in texture and composition but significantly different from the Earth's known crustal rocks. Of primary importance was Howard's discovery of nickel in the irons and the metal grains of the stones. This linked the two as belonging to the same natural phenomenon. These chemical results, published in February 1802, persuaded some of the leading scientists in England, France, and Germany that bodies do fall from the sky. Within a few months, chemists in France reported similar results and a new field of study was inaugurated internationally, although opposition lingered on until April 1803, when nearly 3,000 stones fell at L'Aigle in Normandy and transformed the last skeptics into believers. Chladni immediately received full credit for his hypothesis of falls, but decades passed before his linking of falling bodies with fireballs received general acceptance. His hypothesis of their origin in cosmic space met with strong resistance from those who argued that stones formed within the Earth's atmosphere or were ejected by lunar volcanoes. After 1860, when both of these hypotheses were abandoned, there followed a century of debate between proponents of an interstellar versus a planetary origin. Not until the 1950s did conclusive evidence of their elliptical orbits establish meteorite parent bodies as members of the solar system. Thus, nearly 200 years passed before the questions of origin that Chladni raised finally were resolved. [source]

    Heterogeneous agglutinitic glass and the fusion of the finest fraction (F3) model

    Abhijit Basu
    They include (1) theoretical expectations that shock pulses should engulf and melt smaller grains more efficiently than larger grains, (2) experimental results of impact shock, albeit at lower than presumed hypervelocity impacts of micrometeorites on the lunar regolith, and (3) new analyses confirming previous results that average compositions of agglutinitic glass are biased towards that of the finest fraction of lunar soils from which they had formed. We add another reason in support of the F3 model. Finer grains of lunar soils are also much more abundant. Hence, electrostatic forces associated with the rotating terminator region bring the finest grains that are obviously much lighter than courser grains to the surface of the Moon. This further contributes to the preferential melting of the finest fraction upon micrometeoritic impacts. New backscattered electron imaging shows that agglutinitic glass is inhomogeneous at submicron scale. Composition ranges of agglutinitic glass are extreme and deviate from that of the finest fraction, even by more than an order of magnitude for some components. Additionally, we show how an ilmenite grain upon impact would produce TiO2 -rich agglutinitic glass in complete disregard to the requirements of fusion of the finest fraction. We propose an addition to the F3 model to accommodate these observations (i.e., that micrometeorite impacts indiscriminately melt the immediate target regardless of grain size or grain composition). We, therefore, suggest that (1) agglutinitic glass is the sum of (a) the melt produced by the fusion of the finest fraction of lunar soils and (b) the microvolume of the indiscriminate target, which melts at high-shock pressures from micrometeoritic impacts, and that (2) because of the small volume of the melt and incorporating cold soil grains, the melt quenched so rapidly that it did not mix and homogenize to represent any preferential composition, for example, that of the finest fraction. [source]

    Diurnal variation of sodium and potassium at Mercury

    D. M. HUNTEN
    The proposed mechanism is deposition of ions and atoms on the cold night side, followed by their outward diffusion and evaporation as the Sun rises. Published criticisms of this mechanism are discussed and answered. The rate at which Na atoms can evaporate from the surfaces of the Moon and Mercury is uncertain, but, after a review of laboratory measurements, we propose that it is substantial at temperatures of 400 K and higher. Possible reasons are discussed why another group does not find the diurnal variation. There are differences in observing geometry, but the matter remains unclear. [source]

    Books and Multimedia Reviews

    Article first published online: 4 FEB 2010
    Book reviewed in this article: Origin of the Earth and Moon edited by R. M. Canup and K. Righter Bolshaya Medveditsa (Great Bear), No 1 edited by Yuri A. Vedernikov [source]

    Hard X-ray emission of the Earth's atmosphere: Monte Carlo simulations

    S. Sazonov
    ABSTRACT We perform Monte Carlo simulations of cosmic ray-induced hard X-ray radiation from the Earth's atmosphere. We find that the shape of the spectrum emergent from the atmosphere in the energy range 25,300 keV is mainly determined by Compton scatterings and photoabsorption, and is almost insensitive to the incident cosmic ray spectrum. We provide a fitting formula for the hard X-ray surface brightness of the atmosphere as would be measured by a satellite-borne instrument, as a function of energy, solar modulation level, geomagnetic cut-off rigidity and zenith angle. A recent measurement by the INTEGRAL observatory of the atmospheric hard X-ray flux during the occultation of the cosmic X-ray background by the Earth agrees with our prediction within 10 per cent. This suggests that Earth observations could be used for in-orbit calibration of future hard X-ray telescopes. We also demonstrate that the hard X-ray spectra generated by cosmic rays in the crusts of the Moon, Mars and Mercury should be significantly different from that emitted by the Earth's atmosphere. [source]

    Space and terrestrial photovoltaics: synergy and diversity,

    Sheila G. Bailey
    A historical view of the research and development in photovoltaics from the perspective of both the terrestrial and the space communities is presented from the early days through the 1970s and 1980s, 1990s and beyond. The synergy of both communities, both at the beginning and in the present, and hopefully in the future, are highlighted, with examples of the important features in each program. The space community which was impressed by the light weight and reliability of photovoltaics drove much of the early development. Even today, nearly every satellite and other scientific space probe that has been launched has included some solar power. However, since the cost of these power systems was only a small fraction of the satellite and launch cost, the use of much of this technology in the terrestrial marketplace was not feasible. It was clear that the focus of the terrestrial community would be best served by reducing costs. This would include addressing a variety of manufacturing issues and raising the rate of production. Success in these programs and a resulting globalization of effort resulted in major strides in the reduction of PV module costs and increased production. Although, the space community derived benefit from some of these advances, its focus was on pushing the envelope with regard to cell efficiency. The gap between theoretical efficiencies and experimental efficiencies for silicon, gallium arsenide and indium phosphide became almost nonexistent. Recent work by both communities have focused on the development thin-film cells of amorphous silicon, CuInSe2 and CdTe. These cells hold the promise of lower costs for the terrestrial community as well as possible flexible substrates, better radiation resistance, and higher specific power for the space community. It is predicted that future trends in both communities will be directed toward advances through the application of nanotechnology. A picture is emerging in which the space and terrestrial solar cell communities shall once again share many common goals and, in fact, companies may manufacture both space and terrestrial solar cells in III,V materials and thin-film materials. Basic photovoltaics research, including these current trends in nanotechnology, provides a valuable service for both worlds in that fundamental understanding of cell processes is still vitally important, particularly with new materials or new cell structures. It is entirely possible that one day we might have one solar array design that will meet the criteria for success in both space and on the Earth or perhaps the Moon or Mars. Published in 2002 by John Wiley & Sons, Ltd. [source]

    A Red Moon over the Mall: The Sputnik Panic and Domestic America

    Ryan Boyle
    First page of article [source]

    Running to the Moon: The Articulation and Construction of Self in Marathon Runners

    Erica L. Reischer
    In this essay, I will consider how individuals engage the marathon in the service of a project of self-transformation. To that end, I will examine cultural meanings and symbols associated with the marathon, and the way in which those meanings interact with the self-system of the runners who choose to participate in the marathon. In addition, since the marathon is ultimately a cultural practice centered on the body, I will also explore the physical and material dimension of the marathon experience. This paper thus provides an account that begins to elucidate the way in which culturally-situated individuals symbolically and physically engage the marathon as a means to actively and intentionally promote self-development. [source]

    An Importance Sampling Method to Evaluate Value-at-Risk for Assets with Jump Risk,

    Ren-Her Wang
    Abstract Risk management is an important issue when there is a catastrophic event that affects asset price in the market such as a sub-prime financial crisis or other financial crisis. By adding a jump term in the geometric Brownian motion, the jump diffusion model can be used to describe abnormal changes in asset prices when there is a serious event in the market. In this paper, we propose an importance sampling algorithm to compute the Value-at-Risk for linear and nonlinear assets under a multi-variate jump diffusion model. To be more precise, an efficient computational procedure is developed for estimating the portfolio loss probability for linear and nonlinear assets with jump risks. And the titling measure can be separated for the diffusion and the jump part under the assumption of independence. The simulation results show that the efficiency of importance sampling improves over the naive Monte Carlo simulation from 7 times to 285 times under various situations. We also show the robustness of the importance sampling algorithm by comparing it with the EVT-Copula method proposed by Oh and Moon (2006). [source]

    Double whammy: seeing the Sun and Moon at Glastonbury

    ASTRONOMY & GEOPHYSICS, Issue 4 2010
    Article first published online: 23 JUL 2010
    No abstract is available for this article. [source]

    Astrobiology on the Moon

    ASTRONOMY & GEOPHYSICS, Issue 4 2010
    Ian A Crawford
    Meeting report Ian Crawford and Charles Cockell report on an RAS Specialist Discussion Meeting held on Friday 14 May 2010. [source]

    Mapping Moon with hydrogen

    ASTRONOMY & GEOPHYSICS, Issue 6 2009
    Article first published online: 23 NOV 200
    No abstract is available for this article. [source]

    Exploring the Moon: a UK perspective

    ASTRONOMY & GEOPHYSICS, Issue 1 2008
    Dr Mahesh Anand
    No abstract is available for this article. [source]

    Hands across the sea , and space

    ASTRONOMY & GEOPHYSICS, Issue 3 2007
    Article first published online: 12 JUN 200
    NASA and the British National Space Centre have signed a historic agreement to study jointly how the two space agencies might work together on future planetary explorations to the Moon and beyond, including a feasibility study on a possible collaborative lunar robot programme. [source]

    An unrecorded Shropshire modeller of the Moon

    ASTRONOMY & GEOPHYSICS, Issue 1 2000
    P D Hingley
    Click HERE to view the article. [source]

    Poll Driven Government: A Review of Public Administration in 2001

    Narelle Miragliotta
    The approach of the Howard Coalition government to public administration in 2001 was consistent with the conventional wisdom that governments typically ,play it safe' in an election year. The government's preoccupation with winning a third term in office was a significant determinant of the policy responses of the government on a number of key issues. The events of 2001 serve as a vivid reminder that policy considerations are ultimately subject to the dictates of the electoral cycle. This is the sixth administrative essay publsihed in the journal since the editors resumed the administrative chronicles in 1996. Earlier administrative essays include J Stewart 55(1) 196; S Prasser 56(1) 1997; J Homeshaw 57(3) 1998; J Moon 58(2) 1999; C Broughton and J Chalmers 60(1) 2000. [source]

    A view of extraterrestrial soils

    G. Certini
    Summary The nature of soils on celestial bodies other than Earth is a growing area of research in planetary geology. However, disagreement over the significance of these deposits arises, in part, through the lack of a unified concept and definition of soil in the literature. The pragmatic definition ,medium for plant growth' is taken by some to imply the necessity of biota for soil to exist, and has been commonly adopted in the planetary science community. In contrast, a more complex and informative definition is based on scientific theory: soil is the (bio)geochemically/physically altered material at the surface of a planetary body that encompasses surficial extraterrestrial telluric deposits. This definition is based on the premise that soil is a body that retains information about its environmental history and that it does not need the presence of life to form. Four decades of missions have gathered geochemical information regarding the surface of planets and bodies within the Solar System, and information is quickly increasing. Reviewing the current knowledge on properties of extraterrestrial regoliths, we conclude that the surficial deposits of Venus, Mars and our moon should be considered to be soils in a pedological sense, and that Mercury and some large asteroids are covered in mantles that are soil candidates. A key environmental distinction between Earth and other Solar System bodies is the presence of life, and because of this dissimilarity in soil-forming processes, it is reasonable to distinguish these (presently) abiotic soils as Astrosols. Attempts to provide detailed classifications of extraterrestrial soils are premature, given our poor current knowledge of the Universe, but they highlight the fact that Earth possesses almost-abiotic environments that lend themselves to providing more understanding about telluric bodies of the Solar System. "He found himself in the neighbourhood of the asteroids 325, 326, 327, 328, 329, and 330. He began, therefore, by visiting them, in order to add to his knowledge." (Excerpt from the The Little Prince by Antoine de Saint-Exupéry) [source]

    Lunar cycles and reproductive activity in reef fishes with particular attention to rabbitfishes

    FISH AND FISHERIES, Issue 4 2004
    Akihiro Takemura
    Abstract Cues from the moon influence synchrony in growth, feeding, migration, behaviour and reproduction of many reef fishes. Compared with comprehensive studies on the annual and daily activities of fish, few physiological studies have paid attention to the importance of lunar cues in reproductive activities. We review mutual and interesting relationships between fish reproduction and environmental changes induced by the moon, with particular emphasis on the reproductive activity of the rabbitfishes (Siganidae). Rabbitfish species exhibit, in nature, a definitive reproductive season, which differs among the tropical areas. During the reproductive season, synchronous spawning of rabbitfish is associated with a particular lunar phase. The lunar phase used by the respective species is similar in different regions on the earth. Histological observations revealed that gonads develop synchronously towards a peak around the spawning lunar phase, after which the gonads return to spent condition. Concomitant with gonadal development, sex steroid hormones were produced under the influence of gonadotropin (GtH). Injections of human chronic gonadotropin (hCG) to the fish that are undergoing active spermatogenesis accelerated testicular maturation. These results suggest that hormonal response in maturing the gonads in rabbitfish is under the regulation of GtH, and that pituitary secretion of GtH according to the lunar cycle accounts for the lunar rhythm in gonadal development. We speculate that the cues from the moon can be recognized by the higher parts of the hypothalamus,pituitary,gonadal axis. Possible relationships between exogenous environmental factors and the lunar-reproductive rhythm are also discussed. [source]

    Horizontal and vertical movements of juvenile bluefin tuna (Thunnus orientalis) in relation to seasons and oceanographic conditions in the eastern Pacific Ocean

    Abstract Electronically tagged juvenile Pacific bluefin, Thunnus orientalis, were released off Baja California in the summer of 2002. Time-series data were analyzed for 18 fish that provided a record of 380 ± 120 days (mean ± SD) of ambient water and peritoneal cavity temperatures at 120 s intervals. Geolocations of tagged fish were estimated based on light-based longitude and sea surface temperature-based latitude algorithms. The horizontal and vertical movement patterns of Pacific bluefin were examined in relation to oceanographic conditions and the occurrence of feeding events inferred from thermal fluctuations in the peritoneal cavity. In summer, fish were located primarily in the Southern California Bight and over the continental shelf of Baja California, where juvenile Pacific bluefin use the top of the water column, undertaking occasional, brief forays to depths below the thermocline. In autumn, bluefin migrated north to the waters off the Central California coast when thermal fronts form as the result of weakened equatorward wind stress. An examination of ambient and peritoneal temperatures revealed that bluefin tuna fed during this period along the frontal boundaries. In mid-winter, the bluefin returned to the Southern California Bight possibly because of strong downwelling and depletion of prey species off the Central California waters. The elevation of the mean peritoneal cavity temperature above the mean ambient water temperature increased as ambient water temperature decreased. The ability of juvenile bluefin tuna to maintain a thermal excess of 10°C occurred at ambient temperatures of 11,14°C when the fish were off the Central California coast. This suggests that the bluefin maintain peritoneal temperature by increasing heat conservation and possibly by increasing internal heat production when in cooler waters. For all of the Pacific bluefin tuna, there was a significant correlation between their mean nighttime depth and the visible disk area of the moon. [source]

    Annual cycle of clupeiform larvae around Gran Canaria Island, Canary Islands

    Abstract The distribution and abundance of fish larvae was studied along the eastern and southern shelf of Gran Canaria Island (Canary Islands) from July 2000 to June 2001. Oblique bongo hauls were carried out fortnightly during the daytime, coinciding with days of full and new moon. During February, the area was sampled every 2,5 days. About 17.3% of the ichthyoplanktonic community was composed of clupeiform larvae: 92.9% of these larvae were Sardinella aurita, whereas 4.7% and 2.4% were respectively Engraulis encrasicolus and Sardina pilchardus. Sardinella aurita larvae appeared during the whole year with two periods of maximum abundance: June to September and December to February. During the full moon their abundance was on average 38.5% (±6.8%) of their numbers during the new moon, showing a clear lunar periodicity. Engraulis encrasicolus larvae appeared from November to March, also coinciding with the new moon. Sardina pilchardus larvae only appeared during two short periods, both coinciding with filaments shed from the African coastal upwelling which reached the island. This fact confirms the transport of fish larvae from the upwelling area off northwest Africa to the Canary Islands, promoting a genetic flow among both sites. [source]

    The intersection of scientific and indigenous ecological knowledge in coastal Melanesia: implications for contemporary marine resource management*

    Simon Foale
    Fundamental differences in the worldviews of western marine scientists and coastal Melanesian fishers have resulted in very different conclusions being drawn from similar sets of observations. The same inductive logic may lead both scientists and indigenous fishers to conclude that, say, square-tail trout aggregate at a certain phase of the moon in a certain reef passage, but different assumptions derived from disparate worldviews may lead to very different conclusions about why the fish are there. In some cases these differences have significant implications for the way marine resources are (or are not) exploited and managed. Here I analyse examples of what I call empirical gaps in both scientific and indigenous knowledge concerning the biology and ecology of fished organisms that in some cases have led to the poor management of stocks of these species. I argue that scientific education can complement indigenous knowledge systems and thus lead to improved resource management, despite some claims that scientific and indigenous knowledge systems are incommensurable. [source]

    Effect of seawater temperature on reproductive seasonality and fecundity of Pseudoplexaura porosa (Cnidaria: Octocorallia): latitudinal variation in Caribbean gorgonian reproduction

    Samantha J. De Putron
    Abstract. The majority of tagged colonies of Pseudoplexaura porosa in Bermuda were reproductive over 2 months in the summer. They spawned 5,8 d after the full moon, with a peak on the sixth day, similar to colonies in Panama. The months of spawning were August and September in 1998, but July and August in 1999 and 2000. This temporal difference between the months of spawning corresponded to inter-annual variations in seawater temperature profiles. Initial gamete development each year occurred only when the daily mean seawater temperature during the month before spawning exceeded 27°C. There was a significant positive relationship between reproductive effort (gamete volume) of colonies and rising seawater temperature in the month preceding spawning; this was true for both the initial and the second spawning months. The end of the reproductive season each year was triggered by the decline in seawater temperature past the summer maximum. The duration of the reproductive season of conspecifics at the central Caribbean reef of Panama is 2 months longer than in Bermuda. This can be explained by the smaller annual temperature range at the lower latitude and the earlier onset of temperatures favorable for gamete development. Fecundity estimates for members of P. porosa (mean oocyte and spermary densities) in Bermuda were lower than for conspecifics in Panama. The shorter reproductive season in Bermuda, in addition to the lower fecundity of colonies, indicates that reproduction in P. porosa is compromised at this high latitude reef. [source]