Are all maps mental maps?     

Axelsen Bjørn  Jones Michael Dr. 《GeoJournal》1987,14(4):447-464

The article focuses on the way in which map content reflects the cartographer's World view and system of values. Different World views are illustrated historically. Examples of topographical, land-use and vegetation maps from different parts of the World indicate the prevalence of Eurocentric perceptions in cartography. Different geological maps of Norden show how the visual image depends on the classification system adopted. All maps are mental maps in that their content is culturally determined and ethnocentric in origin.  相似文献   

The 1s 2s states of negative hydrogen     

Claus Ingemann-Hilberg  Mogens Rudkjøbing 《Astrophysics and Space Science》1970,6(1):101-106

Term values for the 1s 2s states of H^– are calculated with the use of simple eigenfunction approximations constructed on the basis of available Hartree-type functions for the 1s ² and 2s ² states of the ion. The results seem to support a tentative identification of the interstellar diffuse absorption bands at 4890 and 6180 as due to negative hydrogen.  相似文献   

Galactic longitude dependence of the intensity ratio of the diffuse interstellar absorption bands at λλ6180 and 4430     

Mogens Rudkjøbing 《Astrophysics and Space Science》1970,6(1):157-160

Equivalent widths, as published by Seddon, for the diffuse interstellar absorption band at 6180 are compared with photoelectric 4430 indices for ten stars in the northern Milky Way. The intensity ratio is found to depend on galactic longitude in a way similar to that found by Johnson for the ratioA _V /E _B–V of total to selective interstellar absorption.The dependence found, combined with deductions from a tentative identification of the bands as due to negative hydrogen, points to a direction for the galactic magnetic field that is in better agreement with the direction derived from rotation measures of extragalactic sources than with that based on the dust-hypothesis interpretation of interstellar optical polarization.  相似文献   

The evershed flow in the transition region chromosphere-photosphere     

J. Bønes  P. Maltby 《Solar physics》1978,57(1):65-71

The Mgb₁ line profile is studied as a function of spatial position in the sunspot region. Comparing the wavelengths of the core and the wing, in and just outside the penumbra, a reversal in the shift is detected. The displacements of the core and the wing are interpreted as horizontal motions directed into the spot in the chromosphere and as a flow directed out of the spot in deeper layers.Systematic wavelength shifts are detected in the line core in some regions outside the penumbra. This is interpreted as a chromospheric velocity field usually directed horizontally away from the spot.  相似文献   

Calibration of estuarine current crosses     

Björn Kjerfve 《Estuarine, Coastal and Shelf Science》1982,15(5):553-559

Tethered current crosses are simple, reliable tools in making measurements of estuarine currents in the absence of surface waves. The standard error of the estimate of current speed is less than 5 cm s^?1 for the particular crosses and weights used in a calibration experiment. The useful velocity range of these current crosses was 8–147 cm s^?1, corresponding to a measured angle, α, from 2° to 30°. Regression of the independently measured current speed on $\text{(tan α)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ yielded coefficients of determination greater than 0·94, indicating that the drag coefficient is not a function of current speed. However, the calculated drag coefficients varied widely from 0·66 to 2·55, depending on the particular combination of cross and weight, varying drastically from the commonly assumed drag coefficient value of 1·12. Thus, in using current crosses, it is imperative to calibrate each cross against a current meter reading to determine an appropriate value for the drag coefficient for a particular current cross and weight.  相似文献   

Nuclear and incommensurate magnetic structure of NaFeGe2O6 between 5?K and 298?K and new data on multiferroic NaFeSi2O6     

G��nther J. Redhammer  Anatoliy Senyshyn  Martin Meven  Georg Roth  Sebastian Prinz  Astrid Pachler  Gerold Tippelt  Clemens Pietzonka  Werner Treutmann  Markus Hoelzel  Bj?rn Pedersen  Georg Amthauer 《Physics and Chemistry of Minerals》2011,38(2):139-157

The compound NaFeGe₂O₆ was grown synthetically as polycrystalline powder and as large single crystals suitable for X-ray and neutron-diffraction experiments to clarify the low temperature evolution of secondary structural parameters and to determine the low temperature magnetic spins structure. NaFeGe₂O₆ is isotypic to the clinopyroxene-type compound aegirine and adopts the typical HT-C2/c clinopyroxene structure down to 2.5?K. The Na-bearing M2 polyhedra were identified to show the largest volume expansion between 2.5?K and room temperature, while the GeO₄ tetrahedra behave as stiff units. Magnetic susceptibility measurements show a broad maximum around 33?K, which marks the onset of low-dimensional magnetic ordering. Below 12?K NaFeGe₂O₆ transforms to an incommensurately modulated magnetic spin state, with k?=?[0.323, 1.0, 0.080] and a helical order of spins within the M1-chains of FeO₆ octahedra. This is determined by neutron-diffraction experiments on a single crystal. Comparison of NaFeGe₂O₆ with NaFeSi₂O₆ is given and it is shown that the magnetic ordering in the latter compound, aegirine, also is complex and is best described by two different spin states, a commensurate one with C2??/c?? symmetry and an incommensurate one, best being described by a spin density wave, oriented within the (1 0 1) plane.  相似文献   

Improving a tree-ring reconstruction from west-central Scandinavia: 900?years of warm-season temperatures     

Bj?rn E. Gunnarson  Hans W. Linderholm  Anders Moberg 《Climate Dynamics》2011,36(1-2):97-108

Dendroclimatological sampling of Scots pine (Pinus sylvestris L.) has been made in the province of J?mtland, in the west-central Scandinavian mountains, since the 1970s. The tree-ring width (TRW) chronology spans several thousand years and has been used to reconstruct June?CAugust temperatures back to 1632 bc. A maximum latewood density (MXD) dataset, covering the period ad 1107?C1827 (with gap 1292?C1315) was presented in the 1980s by Fritz Schweingruber. Here we combine these historical MXD data with recently collected MXD data covering ad 1292?C2006 into a single reconstruction of April?CSeptember temperatures for the period ad 1107?C2006. Regional curve standardization (RCS) provides more low-frequency variability than ??non-RCS?? and stronger correlation with local seasonal temperatures (51% variance explained). The MXD chronology shows a stronger relationship with temperatures than the TRW data, but the two chronologies show similar multi-decadal variations back to ad 1500. According to the MXD chronology, the period since ad 1930 and around ad 1150?C1200 were the warmest during the last 900?years. Due to large uncertainties in the early part of the combined MXD chronology, it is not possible to conclude which period was the warmest. More sampling of trees growing near the tree-line is needed to further improve the MXD chronology.  相似文献   

Multixenobiotic resistance, acetyl-choline esterase activity and total oxyradical scavenging capacity of the Arctic spider crab, Hyasaraneus, following exposure to bisphenol A, tetra bromo diphenyl ether and diallyl phthalate     

Minier C  Forget-Leray J  Bjørnstad A  Camus L 《Marine pollution bulletin》2008,56(8):1410-1415

The Arctic has become a sink for persistent organic pollutants (POPs) originating from lower latitudes, and relatively high levels have been found in different biota. Recent studies have identified detrimental effects on wildlife including endocrine disruption, impairment of enzyme activity, and reduced immune function. The Arctic spider crab, Hyas araneus, shown interesting potential for its use as sentinel organism in polar ecosystems. This study investigated the effect of 2,2',4,4'-tetra bromo diphenyl ether (BPDE), bisphenol A (BPA), and diallyl phthalte (DPA) on H. araneus in a three weeks exposure study. Expression of multixenibiotic resistance (MXR) proteins has been studied using the C219 monoclonal antibody which allows identifying an immunoreactive protein of 40 kDa in the digestive gland while no such protein could be observed in the gills. Expression of this protein was increased by exposure to DPA (+75%; p<0.05, n=10). All compounds significantly affected muscle acetylcholine esterase (AChE) activity (p<0.05, n=10) with 50 microg/L DPA having the strongest effect by lowering the value to 37% of control. The total oxyradical scavenging capacity measured in the digestive gland toward peroxyl, hydroxyl and peroxynitrite was also significantly reduced indicating a decreased resistance to oxidative stress generated by DPA (p<0.05, n=5). These results thus suggest the potential detrimental effects of DPA even at concentration as low as 50 microg/L on H. araneus.  相似文献   

Temperature variation at mesopause levels during winter solstice at 78°N     

H.K. Myrabø 《Planetary and Space Science》1984,32(2):249-255

Atmospheric temperatures from the polar mesopause are deduced from spectrophotometric measurements of hydroxyl bands and lines in the night airglow made at 78°N during December and January 1980/81 and 1982/83. An overall mean temperature of 220 K is found with a range from 172 to 257 K in the daily mean values. Several warm periods lasting 3–6 days may be due to heat dissipated by gravity waves. One week of consistently low temperatures was apparently connected to a stratospheric warming. Both datasets show a warmer mean temperature later in January than for early and mid-December. The polar OH airglow seems to peak at or just above the mesopause. The data also indicate that the mesopause is situated at approx. 90 km with an upper temperature gradient of 1 K km^?1 indicating a very shallow mesopause. A superposed epoch analysis of 19 consecutive 24-h periods reveals a semidiurnal variation in the temperature around winter solstice with an amplitude of 5 K. No diurnal variation of amplitude greater than 1 K is apparent. Average wind velocity deduced from the amplitude of the semidiurnal temperature variation is 9 m s^?1.  相似文献   

Book reviews     

Wolf Tietze  Gerhard Kortum  W. R. Mead  T. K. Poiker  C. Paddick  George Kish  A. Njøs  H. Mensching  V. Haarmann  Uzo M. Igbozurike  M. M. Yoshino  Mushtaqur Rahman  Lage Wahlström  J. Connell  Kazimierz Dziewonski  Wayland R. Swain  J. Humlum  G. W. Lüttig  Haruko Kishimoto  Mai Britt E. Mørk 《GeoJournal》1982,6(3):270-280

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