Initiation of non-tropical thunderstorms by solar activity

Correlative evidence accumulating since 1926 suggests that there must be some physical coupling mechanism between solar activity and thunderstorm occurrence in middle to high latitudes. Such a link may be provided by alteration of atmospheric electric parameters through the combined influence of high-energy solar protons and decreased cosmic ray intensities, both of which are associated with active solar events. The protons produce excess ionization near and above 20km, while the Forbush decreases a lowered conductivity and enhanced fair-weather atmospheric electric field below that altitude. Consequent effects ultimately lead to a charge distribution similar to that found in thunderclouds, and then other cloud physics processes take over to generate the intense electric fields required for lightning discharge

Thunderstorms observed by radio astronomy Explorer 1 over regions of low man made noise

Radio Astronomy Explorer (RAE) I observations of thunderstorms over regions of low man-made noise levels are analyzed to assess the satellite's capability for noise source differentiation. The investigation of storms over Australia indicates that RAE can resolve noise generation due to thunderstorms from the general noise background over areas of low man-made noise activity. Noise temperatures observed by RAE over stormy regions are on the average 10DB higher than noise temperatures over the same regions in the absence of thunderstorms. In order to determine the extent of noise contamination due to distant transmitters comprehensive three dimensional computer ray tracings were generated. The results indicate that generally, distant transmitters contribute negligibly to the total noise power, being 30DB or more below contributions arriving from an area immediately below the satellite

Unitary groups over local rings

Structural properties of unitary groups over local, not necessarily commutative, rings are developed, with applications to the computation of the orders of these groups (when finite) and to the degrees of the irreducible constituents of the Weil representation of a unitary group associated to a ramified extension of finite local rings

Pengaruh Lingkungan Tropis Indonesia Pada Penuaan Aspal Dan Modulus Kekakuan Resilien Campuran Beraspal

Kinerja struktur perkerasan jalan yang merupakan suatu struktur yang tidak terlindung sangat dipengaruhi oleh kondisi klimatik lokasi di mana jalan tersebut dibangun. Kondisi klimatik ini memberikan pengaruh jangka panjang tidak saja pada kinerja struktur perkerasan jalan tetapi juga pada respon struktur perkerasan tersebut terhadap beban karena kondisi klimatik sangat menentukan kecepatan penuaan aspal. Penuaan aspal adalah suatu parameter yang baik untuk mengetahui durabilitas campuran beraspal. Penuaan ini menyebabkan terjadinya pengerasan pada aspal dan selanjutnya akan meningkatkan kekakuan campuran beraspal dan akhirnya akan mempengaruhi kinerja campuran tersebut. Studi ini bertujuan untuk mengetahui pengaruh lingkungan terhadap penuaan aspal dan pada modulus kekakuan Cement Treated Asphalt Mixture (CTAM) dan Split Mastic Asphalt (SMA) pada iklim tropis Indonesia. Untuk mencapai tujuan tersebut, kedua campuran ini dikondisikan terhadap pengaruh lingkungan dengan cara mengeksposnya secara langsung di udara terbuka selama 0, 1, 3, 6, 9, 12, 15, 18, dan 21 bulan. Uji laboratorium dilakukan pada campuran yang sudah dikondisikan dan pada aspal hasil ekstraksinya. Selain itu, data penuaan aspal kedua campuran yang didapat dari studi ini dibandingkan dengan data sekunder penuaan aspal yang diperoleh dari campuran Hot Rolled Sheet (HRS) yang ada di lapangan. Kata

Tax Competition under Minimum Rates: The Case of European Diesel Excises

This paper estimates Nash-type fiscal reaction functions for European governments competing for revenue from diesel excises. It appears that European governments strategically set their excise levels by responding to their neighbors’ tax rates. This provides evidence for the presence of tax competition in diesel excises. In fact, a 10 percent higher rate in neighboring countries (in terms of the user price) induces a country to raise its own rate by between 2 and 3 percent. This impact is robust for alternative specifications. By imposing restrictions on excise levels, EU harmonization of excises in 1987 and the introduction of a minimum in 1992 exerted a positive impact on the excise level in a number of EU countries. It has not, however, significantly reduced the intensity of tax competition. Indeed, strategic tax responses have not significantly been reduced by these harmonization policies. We also find that high-tax countries appear to compete more aggressively than low-tax countries in the sense that they feature larger strategic tax responses. There is no significant difference between large and small countries.Diesel excise, strategic tax setting, minimum rates, European Union

Design and Development of the Space Shuttle Tail Service Masts

The successful launch of a space shuttle vehicle depends on the proper operation of two tail service masts (TSMs). Reliable TSM operation is assured through a comprehensive design, development, and testing program. The results of the concept verification test (CVT) and the resulting impact on prototype TSM design are presented. The design criteria are outlined, and the proposed prototype TSM tests are described

The late Cretaceous environment of the Arctic: A quantitative reassessment based on plant fossils

Late Cretaceous megafossil floras from the palaeo-Arctic of northeastern Russia and northern Alaska are reviewed in respect of their age, composition, structure and floral dynamics. Palaeofloral correlations and comparisons are made between the two regions. Nine angiosperm-rich, predominantly Cenomanian to Coniacian, floras from the palaeo-Arctic are re-evaluated using Climate Leaf Analysis Multivariate Program (CLAMP) calibrated using a global gridded (0.5° x 0.5°) climate data set derived from that used in climate modelling. Additional floras from lower palaeolatitudes were used to derive latitudinal temperature gradients: seven from N. America, five from around 30 °N palaeolatitude in Europe and one from Kazakhstan. The Arctic climatic determinations, similar to previous estimates, support the existence of a northern Pacific Ocean cold gyre and a warm Arctic Ocean. At palaeolatitudes greater than 80°N floras are insufficiently diverse in woody dicot taxa to use CLAMP, but using CLAMP-derived latitudinal temperature gradients Arctic Ocean coastal environments at 70 Ma and 82°N, and which supported a diverse dinosaur magafauna, are predicted to have experienced a mean annual temperature of 6.3 ± 2.2°C, a warm month mean of 14.5 ± 3.1°C and a cold month mean no colder than -2.0 ± 3.9°C. All uncertainties are 2σ. The new estimates are in good agreement with a wide range of non-palaeobotanical climate proxies and render as an outlier warmer temperature estimates for the Arctic Ocean derived from the TEX86 proxy. Modelling, however, shows that land to ocean temperature gradients could have been steep. The CLAMP estimates also suggest high values for humidity and precipitation consistent with sedimentological indicators and, coupled with warm temperatures, support the existence of a persistent polar cloud cap that helped maintain high terrestrial air temperatures throughout prolonged periods (up to 5 months) of winter darkness