Monochromatic observations of three nebular objects in the direction of NGC 1714

Using a CCD as detector, we have observed three nebulosities not yet listed in catalogues; they all present a planetary nebula morphology and are situated in the immediate neighbourhood (less than 3 arc min to the East) of NGC 1714. Observations have been made through interference filters centered on the main emission lines of these objects.The observations were made at the E.S.O. in La Silla (Chile).European Southern Observatory, La Silla, Santrago de Chile.     

Sisterhood and Seine‐Nets: Engendering Development and Conservation in Ghana's Marine Fishery

As processors and marketers of fish, women fishtraders in the Fanti town of Cape Coast, Ghana have become powerful financers and owners of canoes, nets, and other fishing equipment. Since the 1960s, when motors were first introduced to Ghana's artisanal canoe fleet, two interrelated processes have occurred in Cape Coast. First, Ghana's fisheries have become increasingly exploited and—in the case of some species—overfished. Second, the social relations of production in the artisanal sector have shifted from being socially embedded to being more market‐based and impersonal. I argue that two recent Women in Development (WID) projects in particular have contributed to the breakdown of fishtraders’ traditional economic networks and livelihood strategies: (a) loan schemes that target women's associations, and (b) the 1985 Intestate Succession Law, which reconfigured inheritance rights. These WID projects, based on western notions of gender and the household, have created disharmony and mistrust among Cape Coast's fishtraders rather than promoting their “development.” The breakdown of fishtraders’ labor and marketing organizations has resulted in increasingly desperate strategies to get fish, increased degradation of Ghana's marine environment, and uncertainty for the future of the coastal economy.     

Dialogue, metaphors of dialogue and understandings of geography

Increasingly, human and physical geographers alike describe their research practices as involving dialogue of some kind. However, the widespread popularity of the term belies some very different understandings of its meaning and methodological implications. In this paper we reflect on these different conceptions of 'dialogical' geography as a way, first, of illustrating the broad range of understandings of research methodology now current in the discipline and, second, of identifying their implications for three long–standing controversies in the discipline: relativism and the truth of geographical knowledge, the associated dualisms between subject/object, nature/society, and realism/constructionism, and the potential for unity between human and physical geography. We argue that, while dialogue is a potentially fruitful way of understanding and practising geography, that the defence of it, like the attacks on it, is often misconceived.     

Mid-Holocene Hemlock Decline in Eastern North America Linked with Phytophagous Insect Activity

Macrofossil evidence indicates that the mid-Holocene hemlock [Tsuga canadensisL. (Carr.)] decline that occurred over a wide area in eastern North America was associated with phytophagous insect activity.In situhemlock macrofossils and insect remains found in a paludified dunefield at the northern limit of hemlock testify that two defoliation events occurred at 4910 ± 90 and 4200 ± 100 yr B.P., respectively. The sharp coincidence of remains from hemlock needles with chewing damage typical of hemlock looper feeding, head capsules from the hemlock looper (Lambdina fiscellaria) and the spruce budworm (Choristoneura fumiferana), absence of hemlock fruiting remains, and tree-ring anomalies in fossil hemlocks that died prematurely (<165 yr) suggest that defoliation affected hemlock reproductive capacity and pollen productivity, or more likely caused mass mortality. Our findings indicate that defoliation can affect ecosystems for centuries, especially when long-lived tree species are involved.     

The structure of a typical double-ring planetary nebula NGC 2392

Monochromatic photographs in H, [Nii] 6584 and [Oiii] 5007 Å show many different details in the morphological structure of the Eskimo Nebula (NGC 2392). H and [Nii] images show, in a first approximation, similar structure (elliptical inner ring and broken outer ring) whereas both rings in [Oiii] are quite circular and regular in brightness. A photometric study using the method described by Louise (1974) gives various geometrical parameters of both rings which are practically the same for the observed lines. In other words, the classical stratification structure in planetary nebulae is not clearly observed in NGC 2392, in good agreement with previous observations (Wilson, 1950). This fact is probably a consequence of the peculiar structure in the geometry of the nebula. A model consisting of an inner toroid surrounded by a spherical shell is proposed to account for both photometric and spectroscopic observations.     

Sur un formalisme explicitant la loi des distances des planetes

The well-known Titius-Bode law (T-B) giving distances of planets from the Sun was improved by Basano and Hughes (1979) who found: $$a_n = 0.285 \times 1.523^n ;$$ a _n being the semi-major axis expressed in astronomical units, of then-th planet. The integern is equal to 1 for Mercury, 2 for Venus etc. The new law (B-H) is more natural than the (T-B) one, because the valuen=?∞ for Mercury is avoided. Furthermore, it accounts for distances of all planets, including Neptune and Pluto. It is striking to note that this law:

1. does not depend on physical parameters of planets (mass, density, temperature, spin, number of satellites and their nature etc.).
2. shows integers suggesting an unknown, obscure wave process in the formation of the solar system.

In this paper, we try to find a formalism accounting for the B-H law. It is based on the turbulence, assumed to be responsible of accretion of matter within the primeval nebula. We consider the function $$\psi ^2 (r,t) = |u^2 (r,t) - u_0^2 |$$ , whereu ²(r, t) stands for the turbulence, i.e., the mean-square deviation velocities of particles at the pointr and the timet; andu ₀ ² is the value of turbulence for which the accretion process of matter is optimum. It is obvious that Ψ²(r _n,t₀) = 0 forr _n=0.285×1.523 ⁿ at the birth timet ₀ of proto-planets. Under these conditions, it is easily found that $$\psi ^2 (r,t_0 ) = \frac{{A^2 }}{r}\sin ^2 [\alpha log r - \Phi (t_0 )]$$ With α=7.47 and Φ(t ₀)=217.24 in the CGS system, the above function accounts for the B-H law. Another approach of the problem is made by considering fluctuations of the potentialU(r, t) and of the density of matter ρ(r, t). For very small fluctuations, it may be written down the Poisson equation $$\Delta \tilde U(r,t_0 ) + 4\pi G\tilde \rho (r,t_0 ) = 0$$ , withU(r, t)=U ₀(r)+?(r, t ₀ ) and \(\tilde \rho (r,t_0 )\) . It suffices to postulate \(\tilde \rho (r,t_0 ) = k[\tilde U(r,t_0 )/r^2 ](k = cte)\) for finding the solution $$\tilde U(r,t_0 ) = \frac{{cte}}{{r^{1/2} }}\cos [a\log r - \zeta (t_0 )]$$ . Fora=14.94 and ζ(t ₀)=434.48 in CGS system, the successive maxima of ?(r,t ₀) account again for the B-H law. In the last approach we try to write Ψ(r, t) under a wave function form $$\Psi ^2 (r,t) = \frac{{A^2 }}{r}\sin ^2 \left[ {\omega \log \left( {\frac{r}{v} - t} \right)} \right].$$ It is emphasized that all calculations are made under mathematical considerations.     

Silicate determination in sea water: Toward a reagentless electrochemical method

Silicate has been determined in sea water by four different electrochemical methods based on the detection of the silicomolybdic complex formed in acidic media by the reaction between silicate and molybdenum salts. The first two methods are based on the addition of molybdate and protons in a seawater sample in an electrochemical cell. Cyclic voltammetry presents two reduction and two oxidation peaks giving four values of the concentration and therefore increasing the precision. Then chronoamperometry is performed on an electrode held at a constant potential. A semi-autonomous method has been developed based on the electrochemical anodic oxidation of molybdenum, the complexation of the oxidation product with silicate and the detection of the complex by cyclic voltammetry. This method is tested and compared with the classical colorimetric one during ANT XXIII/3 cruise across Drake Passage (January–February 2006). The detection limit is 1 μM and the deviation between both methods is less than 3% for concentrations higher than 10 μM. Finally a complete reagentless method with a precision of 2.6% is described based on the simultaneous formation of the molybdenum salt and protons in a divided electrochemical cell. This latter method should be very useful for developing a reagentless sensor suitable for long term in situ deployments on oceanic biogeochemical observatories.     

Subsistence in coastal fisheries policy: What's in a word?

Consideration of subsistence fishing activities seems particularly relevant to coastal fisheries policy, yet formal recognition of subsistence fishing is often absent from associated policy frameworks. A critical problem is the very meaning of the term “subsistence.” A review of the literature on subsistence, dominated until recently by North American research, reveals a schism between interpretations emphasizing material aspects of subsistence and interpretations highlighting cultural aspects. The North American literature on the subject is heavily influenced by a focus on Arctic indigenous populations emphasizing cultural survival. Ultimately, subsistence can be a matter of survival in the belly, the soul, or both. International case studies suggest that different interpretations of subsistence are appropriate in different circumstances, and that appropriate policy can be fashioned only after the local context of subsistence is understood.     

Coexisting K-rich alkaline and shoshonitic magmatism of arc affinities in the Proterozoic: a reassessment of syenitic stocks in the southwestern Grenville Province

Biotite-rich syenitic stocks in the Mont-Laurier area of the southwestern Grenville Province are shown to belong to the first recorded Proterozoic example of an ultrapotassic, K-rich alkaline and shoshonitic rock association with clear arc affinities. The plutons investigated were previously considered mostly syenitic, typical of nepheline syenite alkaline suites, slightly metamorphosed and late-tectonic with respect to the Grenville orogeny. We find that they postdate the regional metamorphism and comprise a felsic to ultramafic range of rock types belonging to two series: (1) a potassic-to-ultrapotassic, silica-undersaturated series of biotite-rich nepheline-bearing syenite, syenite, monzonite, diorite and pyroxenite, and (2) a shoshonitic, critically silicasaturated series of quartz syenite and amphibole-bearing syenite, with rare monzonite and diorite. The ubiquitous biotite, previously regarded as metamorphic, is reinterpreted as igneous and diagnostic of the potassic character. The shoshonitic and potassic series display the strong enrichment in Al, Ca, K and large-ion-lithophile elements relative to the high-field-strength elements (e.g. Ba/Nb722, La/YB45) and the low contents in Mg that are characteristic of arc-related magmas. The syenitic rocks consistently share the distinctive arc-related geochemical signature of their mafic counterparts. Syenites may thus represent a potential source of paleotectonic information for high grade terranes. Geochemical discriminants (Nb_N/Ta_N and Hf_N/Ti_N ratios) indicate that the shoshonitic and potassic series are unrelated by closedsystem fractionation processes. Rather, the chemical differences between the two series probably reflect differences in source characteristics and conditions of melting. Similar plutons occur throughout the Central Metasedimentary Belt of the southwestern Grenville Province. They define a 1089 to 1076 Ma, 450-km-long grenvillian potassic alkaline plutonic (PAP) province. The presence of this K-rich alkaline province indicates that the scarcity of K-rich rocks in the Precambrian could be only apparent and a consequence of misidentification of K-rich plutons in metamorphosed Precambrian terranes. These 1.1 Ga ultrapotassic to shoshonitic plutonic rocks are geochemically similar to shoshonites and leucitites of the Sunda arc. This similarity suggests that subduction-type enrichment processes were operating in the Proterozoic in ways similar to those of modern settings.