Analysis of the orbit of ariel 1, 1962-15A,near 15th-order resonance

Ariel 1, the first international satellite, was launched on 26 April 1962, into an orbit inclined at 53.85° to the equator, with an initial perigee height near 390 km. On 8 May 1973 the orbit passed through 15th-order resonance and has been determined, with the RAE orbit refinement program PROP, at eight epochs between February and August 1973 using 500 observations.The orbital inclinations during the time of 15th-order resonance, as given by these eight orbits and 31 U.S. Navy orbits, were fitted with a theoretical curve using the THROE computer program, the best fit giving $\text{10}{}^9\text{C}\text{?}{}_{15}\text{= ?370 ± 14}$ and 10⁹S₁₅ = ?114 ± 31.The values of eccentricity were also successfully fitted using THROE, and the results are discussed.     

Sustaining agricultural production and food security in Southern Africa: an improved role for climate prediction?

Livelihoods and household food security in the Southern African region can be extremely vulnerable to the negative effects of climate stress as shown by the 2002–2004 ‘complex emergency.’ Climate prediction may prove a valuable resource in mitigating these effects. If climate prediction is applied successfully, it may be able to help guide responses in populations at risk to reduce vulnerability to climate stress. The study presented here seeks to understand what would constitute an improved role for climate prediction in contributing to sustaining agricultural production and food security in Southern Africa. Investigation undertaken during the 2002/2003 rainy season under regional conditions of elevated disaster risk shows, however, that a number of weaknesses and gaps persistently characterize climate information systems in the Southern African region, and constrain such systems’ ability to benefit key sectors, particularly agriculture. The stakeholder identification of such gaps forms the basis for distilling concrete recommendations to improve process and organizational efficiency. Such recommendations, while developmental, should better enable institutions and stakeholders involved in climate prediction to fulfill their potential in supporting development of successful adaptation strategies in populations and sectors at risk.     

Stocks and dynamics of dissolved and particulate organic matter in the southern Ross Sea, Antarctica

Dissolved and particulate organic matter was measured during six cruises to the southern Ross Sea. The cruises were conducted during late austral winter to autumn from 1994 to 1997 and included coverage of various stages of the seasonal phytoplankton bloom. The data from the various years are compiled into a representative seasonal cycle in order to assess general patterns of dissolved organic matter (DOM) and particulate organic matter (POM) dynamics in the southern Ross Sea. Dissolved organic carbon (DOC) and particulate organic carbon (POC) were at background concentrations of approximately 42 and 3 μM C, respectively, during the late winter conditions in October. As the spring phytoplankton bloom progressed, organic matter increased, and by January DOC and POC reached as high as 30 and 107 μM C, respectively, in excess of initial wintertime conditions. Stocks and concentrations of DOC and POC returned to near background values by autumn (April). Approximately 90% of the accumulated organic matter was partitioned into POM, with modest net accumulation of DOM stocks despite large net organic matter production and the dominance of Phaeocystis antarctica. Changes in NO₃ concentration from wintertime values were used to calculate the equivalent biological drawdown of dissolved inorganic carbon (DIC_equiv). The fraction of DIC_equiv drawdown resulting in net DOC production was relatively constant (ca. 11%), despite large temporal and spatial variability in DIC_equiv drawdown. The C : N (molar ratio) of the seasonally produced DOM had a geometric mean of 6.2 and was nitrogen-rich compared to background DOM. The DOM stocks that accumulate in excess of deep refractory background stocks are often referred to as “semi-labile” DOM. The “semi-labile” pool in the Ross Sea turns over on timescales of about 6 months. As a result of the modest net DOM production and its lability, the role DOM plays in export to the deep sea is small in this region.     

Near-infrared adaptive optics imaging of nuclear spiral structure in the Seyfert galaxy NGC 3227

We present high spatial resolution, near-infrared images in J , H and K of the nucleus of NGC 3227, obtained with the Adaptive Optics Bonnette on the Canada–France–Hawaii Telescope. The ∼0.15 arcsec (17 pc) resolution allows structures to be probed in the core region. Dust obscuration becomes significantly less pronounced at longer wavelengths, revealing the true geometry of the core region. We are able to identify two main features in our maps: (i) a spiralling association of knots with a counterpart in a Hubble Space Telescope F606W image; and (ii) a smaller-scale annulus, orthogonal to the spiral of knots. These features may provide a means to transport material inwards to fuel the active nucleus.     

Research Note: A proposed procedure for ameliorating edge effects in magnetic data transformations

Reduction to pole and other transformations of total field magnetic intensity data are often challenging to perform at low magnetic latitudes, when remanent magnetization exists, and when large topographic relief exists. Several studies have suggested the use of inversion-based equivalent source methods for performing such transformations under those complicating factors. However, there has been little assessment of the importance of erroneous edge effects that occur when fundamental assumptions underlying the transformation procedures are broken. In this work we propose a transformation procedure that utilizes magnetization vector inversion, inversion-based regional field separation and equivalent source inversion on unstructured meshes. We investigated whether edge effects in transformations could be reduced by performing a regional separation procedure prior to equivalent source inversion. We applied our proposed procedure to the transformation of total field magnetic intensity to all three Cartesian magnetic field components using a complicated synthetic example based on a real geological scenario from mineral exploration. While the procedure performed acceptably on this test example, the results could be improved. We pose many questions regarding the various choices and control parameters used throughout the procedure, but we leave the investigation of those questions to future work.     

Vertebral abnormalities in free-living Chinook salmon (Oncorhynchus tshawytscha,Walbaum) in New Zealand

Spinal abnormalities are common in farmed Chinook Salmon in New Zealand. We report spinal abnormalities in adult Chinook salmon which were predominantly hatchery reared and released as smolts and which we term free-living. We compare these to rates seen in farmed New Zealand salmon. 101 free-living adult salmon were radiographically assessed for spinal curvatures (lordosis, kyphosis, scoliosis; LKS) and other vertebral abnormalities. Severity of abnormality was assessed on a three-point scale. Abnormal vertebral bodies were detected in 88.1% of free-living salmon. Spinal curvatures were the most common abnormality type with 83.2% of fish showing this abnormality but only one free-living Chinook had LKS of severity greater than 1. Farmed Chinook salmon are reported to have LKS rates of 29% with 18% of LKS abnormalities of severity greater than 1. These results suggest that free-living Chinook salmon frequently develop spinal abnormalities, but these abnormalities are less severe than those observed in farmed salmon.     

Geology and thermochronometry of the east edge of the Median Batholith (Median Tectonic Zone): a new perspective on Permian to Cretaceous crustal growth of New Zealand

Abstract We report new field, petrological and isotopic data and interpretations from one of New Zealand’s major basement geological boundaries, the contact between the east side of the Median Batholith (formerly Median Tectonic Zone) and the allochthonous Mesozoic terranes of the Eastern Province. In the Nelson and Hollyford–Eglinton areas this contact is a Cenozoic fault, the Median Tectonic Line of earlier workers. However, in the Longwood Range, unfaulted pre-Cenozoic geological relations are preserved intact. Our new Ar–Ar, U–Pb and isotopic data show that the Median Batholith in the Longwood Range consists of two suites. (i) Eastern, isotopically primitive (⁸⁷Sr/⁸⁶Sr_i = 0.702 to 0.703; ?_NdT = + 7 to + 8) trondhjemite and gabbroic rocks of Permian age that we believe are part of the intraoceanic Brook Street arc of the Eastern Province. (ii) Western, isotopically more evolved (⁸⁷Sr/⁸⁶Sr_i = 0.703 to 0.704; ?_NdT = + 3 to + 5) quartz diorites, quartz monzodiorites and rare granites of Middle Triassic to Early Jurassic age that we correlate with a pulse of magmatism elsewhere in the Median Batholith. Field observations in the Longwood Range indicate intrusive, not faulted, contacts between these units and constrain accretion of the Brook Street Terrane to Gondwana to have occurred 230–245 Ma. Intra-batholith shear zones (T ~ 600°C and P ~ 0.2–0.3 GPa) were active at approximately 220 Ma. Modelling of K-feldspar Ar incremental heating ages indicate that most of the Longwood Range had cooled below 175°C by the Middle Jurassic and experienced no subsequent reheating. Significant additional post-accretionary Early Cretaceous and Cenozoic thermotectonic activity in Median Batholith in the Hollyford-Eglinton area is indicated by a new 140 ± 2 Ma U-Pb zircon date on a Largs ignimbrite, as well as by Cenozoic K-feldspar Ar–Ar ages in the Middle Triassic Mistake Diorite.     

Pathology of the liver, kidney and gonad of flounder (Platichthys flesus) from a UK estuary impacted by endocrine disrupting chemicals.

The Mersey estuary is highly contaminated with xenobiotics compared to the nearby Dee estuary. Male flounder, a migratory flatfish caught in the Mersey frequently contains high blood concentrations of the oestrogen controlled, female protein vitellogenin, suggesting that Mersey flounder have been exposed to endocrine disrupting contaminants. Males caught from the Dee contain lower blood vitellogenin levels. Preliminary histopathological examination of 410 flounder from both estuaries, focuses on the liver, kidney and gonads. Hepatic tubular vacuolation, foci of cellular alteration, and hepatocellular tumours were seen. Renal and gonadal pathology included the presence of two Mersey fish with enlarged and abnormal glomeruli, three phenotypic male Mersey flounder with unilateral intersex gonads and one male with bilateral, abnormal ovarian follicular components in the testis. These initial results provide pathological evidence of xenobiotic exposure in flounder sampled from both estuaries. Preliminary findings from flounder sampled from Millport, an offshore site in Southwest Scotland, showed no histopathological evidence of xenobiotic exposure.     

XXIst International Congress of Photogrammetry and Remote Sensing

The XXIst International Congress of Photogrammetry and Remote Sensing was held at the Beijing International Convention Centre, China, from 3rd to 11th July 2008. Reports are given on the Congress as a whole, including the General Assembly, some Technical Commission activities and the Congress Exhibition. Papers from the Congress are published in Volume XXXVII of the International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences.