GIScience Journals Ranking and Evaluation: An International Delphi Study

Researchers’ fame in most scientific fields is closely linked to their publishing capacity, both in terms of quantity and quality. In GIScience, as in other fields, this situation demands that the researcher evaluate and to be very familiar with the scientific journals in which they could publish. Some specialized journals (e.g. Journal of Citation Reports or JCR) are devoted to ranking these reviews according to various methods and criteria. Compared to other scientific communities, GIScience is relatively new and constantly evolving. Therefore, the journals of this field do not benefit from any real formal ranking yet. The objective of this paper is to present the process and results of a study aimed at addressing this gap. More specifically, the challenge is to elaborate an importance ranking of the scientific journals in the field of GIScience. To do so, both a qualitative (Delphi study carried out with 40 international experts) and a quantitative (JCR impact factor) approach has been implemented. This triangulation method leads to an early global ranking of the journals of this field.     

Carbonyl products of the gas phase reaction of ozone with 1,1-disubstituted alkenes

Carbonyl products have been identified and their formation yields measured in experiments involving the gas phase reaction of ozone with 1,1-disubstituted alkenes at ambient T and p=1 atm. of air. Sufficient cyclohexane was added to scavenge the hydroxyl radical in order to minimize OH-alkene and OH-carbonyl reactions. Formation yields (carbonyl formed/ozone reacted) of primary carbonyls were close to the value of 1.0 that is consistent with the mechanism: O₃+R₁R₂C=CH₂ (HCHO+R₁R₂COO)+(1–)(R₁COR₂+H₂COO) where formaldehyde and the ketone R₁ COR₂ are the primary carbonyls and R₁R₂COO and H₂COO are the corresponding biradicals. Measured values of were 0.58–0.82 and indicate modest preferential formation of formaldehyde and the disubstituted biradical as compared to the ketone and the biradical H₂COO. Carbonyls other than the primary carbonyls were identified. Their formation is discussed in terms of subsequent reactions of the disubstituted biradicals R₁R₂COO. Similarities and differences between disubstituted and monosubstituted biradicals are outlined.     

Behavioural-geographical aspects of environmental quality

The behavioural approach in human geography accentuates the view of quality of the environment through man and his value orientations. The quality of environment from the point of view of human experience raises behavioural-geographical questions that are the core of the presented topic. Aspects of environmental imaginations and sensations as well as human value system are presented as variables affecting the structure of the perceived environment and human spatial behaviour. In this context, the authors present results of two behavioural studies that correspond to new models of man and environment from the viewpoint of a behavioural approach. The suggested humanistic approach in behavioural geography emphasizes above all the emotional aspect of the relationship between man and environment, which through environmental values, spatial sensations, and meanings, leads to human spatial behaviour.     

The role of bathymetry and directional wave conditions on observed crescentic bar dynamics

Nearshore sandbars are important features in the surf zone of many beaches because they strongly influence the mean circulation and evolving morphology. Due to variations in wave conditions, sandbars can experience cross-shore migration and vary in shape from alongshore uniform (shore-parallel) to alongshore rhythmic (crescentic). Sandbar dynamics have been studied extensively, but existing observational studies usually do not quantify the processes leading to crescentic bar formation and straightening. This study analyses the dynamics of crescentic bar events at the fetch-limited beach of Castelldefels (northwestern Mediterranean Sea, Spain) using 7.5 years of hourly time-exposure video images and detailed wave conditions. The results show that, despite the generally calm wave conditions, the sandbars were very dynamic in the cross-shore and longshore directions. They often migrated rapidly offshore during storms (up to 70 m in one day) and more slowly onshore during post-storm conditions. Crescentic bars were often present at the study site (48% of the time), but only when the sandbar was at least 10 m from the shoreline. They displayed a large variability in wavelengths (100–700 m), alongshore migration speeds (0–50 m/day) and cross-shore amplitudes (5–20 m). Wavelengths increased for larger bar–shoreline distances and the alongshore migration speeds were strongly correlated with the alongshore component of the radiation stresses. Crescentic patterns typically developed during low–medium energetic waves with limited obliquity ( $\theta \lesssim 20$° at 10 m depth), while bar straightening occurred during medium–high energetic waves with strong oblique angles of incidence ( $\theta \gtrsim 15$°). Overall, this study provides further proof for the important role of wave direction in crescentic bar dynamics and highlights the strong dependence of crescentic bar development on the initial bathymetric configuration.     

Jupiter: New retrieved thermal profiles and ammonia distributions

New thermal profiles of Jupiter are retrieved from recent far infrared spectral measurements and for H₂ mixing ratios varying from 0.8 to 0.94. The effective temperature corresponding to the inferred thermal profile is 123.15 ± 0.35°K. Far-infrared brightness temperature spectra computed from these profiles are compared to experimental data including measurements made at high spectral resolution in the NH₃ν₂ band at 10 μm and in NH₃ pure rotational bands between 40 and 110 μm. It is found that a strong depletion of NH₃ does occur in the Jovian stratosphere and that ammonia seems to be undersaturated in the upper troposphere.     

Recent crustal subsidence at Yellowstone Caldera,Wyoming

Following a period of net uplift at an average rate of 15±1 mm/year from 1923 to 1984, the east-central floor of Yellowstone Caldera stopped rising during 1984–1985 and then subsided 25±7 mm during 1985–1986 and an additional 35±7 mm during 1986–1987. The average horizontal strain rates in the northeast part of the caldera for the period from 1984 to 1987 were: ₁ = 0.10 ± 0.09 strain/year oriented N33° E±9° and ₂ = 0.20 ± 0.09 strain/year oriented N57° W±9° (extension reckoned positive). A best-fit elastic model of the 1985–1987 vertical and horizontal displacements in the eastern part of the caldera suggests deflation of a horizontal tabular body located 10±5 km beneath Le Hardys Rapids, i.e., within a deep hydrothermal system or within an underlying body of partly molten rhyolite. Two end-member models each explain most aspects of historical unrest at Yellowstone, including the recent reversal from uplift to subsidence. Both involve crystallization of an amount of rhyolitic magma that is compatible with the thermal energy requirements of Yellowstone's vigorous hydrothermal system. In the first model, injection of basalt near the base of the rhyolitic system is the primary cause of uplift. Higher in the magmatic system, rhyolite crystallizes and releases all of its magmatic volatiles into the shallow hydrothermal system. Uplift stops and subsidence starts whenever the supply rate of basalt is less than the subsidence rate produced by crystallization of rhyolite and associated fluid loss. In the second model, uplift is caused primarily by pressurization of the deep hydrothermal system by magmatic gas and brine that are released during crystallization of rhyolite and them trapped at lithostatic pressure beneath an impermeable self-sealed zone. Subsidence occurs during episodic hydrofracturing and injection of pore fluid from the deep lithostatic-pressure zone into a shallow hydrostatic-pressure zone. Heat input from basaltic intrusions is required to maintain Yellowstone's silicic magmatic system and shallow hydrothermal system over time scales longer than about 10⁵ years, but for the historical time period crystallization of rhyolite can account for most aspects of unrest at Yellowstone, including seismicity, uplift, subsidence, and hydrothermal activity.     

Libration effects for retrograde satellites in the restricted three-body problem

Numerical explorations of the restricted problem have shown that for stable large nonperiodic retrograde satellite orbits, the motion can be decomposed into a fast reference motion and a slow libration aroundB ₂ We study here this libration in the circular plane Hill's case, for which the reference motion is elliptic. We establish the equations of motion for the coordinates of the centre of this ellipse. We find two integrals of motion: the first is the semi-major axis of the ellipse; the second is essentially Jacobi's integral, translated into the new coordinates. We give a formula for the period of the libration and we find its limiting value for small libration amplitudes. A numerical verification gives very good agreement for all these results.     

Layered mantle structure beneath the western Guyana Shield, Venezuela: Evidence from diamonds and xenocrysts in Guaniamo kimberlites

Mantle xenoliths and xenocrysts from Guaniamo, Venezuela kimberlites record equilibration conditions corresponding to a limited range of sampling in the lithosphere (100-150 km). Within this small range, however, compositions vary considerably, but regularly, defining a strongly layered mantle sequence. Major and trace element compositions suggest the following lithologic sequence: highly depleted lherzolite from 100 to 115 km, mixed ultra-depleted harzburgite and lherzolite from 115 to 120 km, relatively fertile lherzolite from 120 to 135 km, and mixed depleted harzburgite and relatively fertile lherzolite from 135 to 150 km. Based on comparison with well-documented mantle peridotites and xenocrysts from elsewhere, we conclude that the Meso-proterozoic Cuchivero Province (host to the Guaniamo kimberlites) is underlain by depleted and ultra-depleted shallow Archean mantle that was underplated, and uplifted, by Proterozoic subduction, perhaps more than once. These Proterozoic subduction events introduced less-depleted oceanic lithosphere beneath the Archean section, which remains there and is the source of the abundant Guaniamo eclogite-suite diamonds that have ocean-floor geochemical signatures. Although diamond-indicative low-Ca Cr-pyrope garnets are abundant, they are derived primarily from the shallow depleted layer within the field of graphite stability, and the rare peridotite-suite diamonds are either metastably preserved at these shallow depths, or were derived from the small amount of depleted lithosphere sampled by these kimberlites that remains within the diamond stability field (the mixture of Archean and Proterozoic mantle in the depth range 135-150 km).