The geology of the angareb ring dike complex,northwestern ethiopia

The Angareb Ring Dike Complex is located in Begemder Province in northwestern Ethiopia, 55 kilometers NNW of the provincial capital Gondar. The structure was first identified in 1973 from Landsat 1 satellite imagery analysis of the East African Rift System. The complex is exposed on the floor of the Tana Graben, a feature bearing structural affinity to the East African Rift. A post-early Miocene age is ascribed to the complex. Association with other as yet univestigated circular features may define a volcanic province of early continental rifting in Ethiopia. Contained within the ring structure is a heterogenous tuff breccia of over 100 cubic kilometers in volume, composed of massive agglomorates, ash flows, welded tuffs, and subaqueous tuffs. The tuff is interpreted as filling a subsiding caldron above an eviscerating magma chamber. Mineralogy and chemical analyses depict a fractionating basaltic magma of transitional-mildly alkaline composition. Partial melting of the Precambrian basement is envisioned to explain the subalkaline granites. Comparison of chemical data with regional petrochemical interpretations suggests that the complex represents the beginning of central vent activity in the waning stages of Tertiary volcanism in Ethiopia.     

A study of the diurnal behavior of boundary-layer winds at the Boulder Atmospheric Observatory

Diurnal wind variations are examined at the Boulder Atmospheric Observatory which is located 25 km east of the foothills of the Rocky Mountains. Data were obtained from a 300-m tower which was instrumented at eight levels and operated almost continuously for three weeks during September 1978. Observations on clear days, for which the diurnal heating and cooling of the local terrain slopes can be expected to affect the winds, show that daytime winds tend to be easterly (upslope) throughout the 300-m depth. At night, a temperature inversion typically develops to about 100 m. Below this level, the nocturnal flow tends to be downslope; above the inversion, a distinctly different regime of flow develops. A diurnal wind oscillation, characterized by strong southerly flow beginning near sunset and ending near midnight, occurred in the upper layer on 25% of the days during the study period. Rapid clockwise rotation of the wind vector occurred during the period of increased wind speed. This oscillation occurred only on days when the synoptic-scale geostrophic wind was southerly. It is suggested that this non-steady state behavior is an inertial oscillation affected by the diurnally varying temperature gradients and local topography.     

The Near-Earth Objects Follow-Up Program

We present the results of photometric observations of the near-Earth asteroids (1943) Anteros, (2102) Tantalus, (2212) Hephaistos, (3199) Nefertiti, (5751) Zao = 1992 AC, (6322) 1991 CQ, (7474) 1992 TC, and 1989 VA made between 1982 and 1995. Synodic rotation periods in the range from 2.39 to 5.54 hr were derived for five of them, and we were able to place lower limits on periods of (2212) and (5751)—both > 20 hr. Only the period of the low amplitude case of (1943) was not constrained. The most interesting results were obtained for the following objects: (2102), a fast rotator (period 2.39 hr) in an extremely inclined orbit (i≈ 64°); (2212), a low amplitude slow rotator considered as an inactive cometary nucleus candidate; (3199), which showed similar lightcurves at quite different positions of the phase angle bisector, constraining its rotational pole; and 1989 VA, an unusual Aten asteroid with a rotation period of 2.51 hr and a relatively large amplitude. Overall, these results continue the pattern that NEO spins exhibit a bimodal distribution of spin rates.     

Ergebnisse neuerer Spezialforschungen in den deutschen Alpen

Ohne Zusammenfassung     

Force resultants for deep-water wave-excited offshore structures

Concepts are developed which lead to an improved understanding of the characteristics of the wave forces that act on deep-water, jacket-type offshore structures. These concepts are the result of comprehensive examinations of both the inertia and the drag force components of the wave excitation. It is shown that, under conditions which are of practical importance, the resultants of the inertia and drag force components can both be expressed in terms of the motion of the sea surface. Fundamental modal forces which govern fundamental modal responses for offshore structures are also examined, and the relationships between these modal forces and the resultants of the inertia and drag force components are established. The structural response itself is further examined, and valuable information is developed which is believed to be of practical importance.     

cDNA cloning of an aryl hydrocarbon receptor from Baikal seals (Phoca sibirica)

Species differences in sensitivity to related planar halogenated aromatic hydrocarbons (PHAH) add significant uncertainty in assessing the ecological risk to aquatic mammals. To investigate mechanisms of PHAH sensitivity in aquatic mammals, we cloned and sequenced the cDNA of Baikal seal aryl hydrocarbon receptor (AHR), an intracellular protein that initiates PHAH-mediated effects. The Baikal seal AHR cDNA has an open reading frame of 843 amino acid residues with a predicted molecular mass of 94.6 kDa. Comparison of AHR amino acid sequences indicated a high degree of sequence conservation (98%) between Baikal and harbor seals. The high conservation of AHRs between Baikal and harbor seals indicates that these seals express AHR proteins closely related structurally. In our previous report (Kim & Hahn, 2002), the dioxin-binding affinity of the harbor seal AHR was at least as high as that of the AHR from a dioxin-sensitive strain of mice, suggesting that this seal species may be sensitive to PHAH effects. This implies that Baikal seal may also be sensitive to dioxin effects.     

Understanding the impact of droughts in the Yarmouk Basin,Jordan: monitoring droughts through meteorological and hydrological drought indices

This article assesses drought status in the Yarmouk Basin (YB), in northern Jordan, using the Standardized Precipitation Index (SPI), the Standardized Water-Level Index (SWI), and the Percent Departure from Normal rainfall (PDNimd) during the years 1993–2014. The results showed that the YB suffers from frequent and irregular periods of drought as variations in drought intensity and frequency have been observed. The SPI results revealed that the highest drought magnitude of ??2.34 appeared at Nuaimeh rainfall station in 1991. This station has also experienced severe drought particularly in years 1995, 1999, 2005, and 2012 with SPI values ranging from ??1.51 to ??1.59. Some other rainfall stations such as Baqura, Ibbin, Khanasiri, Kharja, Mafraq police, Ramtha, Turra, and Umm Qais have also suffered several periods of drought mostly in 1993. The SWI results show the highest extreme drought events in 2001 in Souf well while other extreme drought periods were observed at Wadi Elyabis well in 1994 and at Mafraq well in 1995. As compared to SPI maps, our SWI maps reflect severe and extreme drought events in most years, negatively impacting the groundwater levels in the study area.