Multicolor photometry of CH Cygni in 1978–1998

We present the results of long-term (1978–1998) infrared and optical observations of the unique symbiotic system CH Cygni. The system’s IR brightness and color variations are generally consistent with a model in which the source is surrounded by a dust envelope with variable optical depth. There was evidence for a hot source in the CH Cyg system during the entire period from 1978 to 1998, with the exception of several hundred days in 1987–1989. Over the observation period, there was tendency for the system to gradually redden at 0.36–5 µm, accompanied by a brightness decrease at 0.36–2.2µm and a brightness increase at 3.5 and 5 µm. The “activation” of the cool sources in 1986–1989 nearly coincided with the disappearance of radiation from the hot source. The dust envelope of CH Cyg is not spherically symmetrical, and its optical depth along the line of sight is substantially lower than its emission coefficient, the mean values being τ_ex(L)～0.06 and τ_em(L)～0.16. We confirm the presence of a 1800-to 2000-day period in both the optical and IR, both accounting for, and not accounting for, a linear trend. The spectral type of the cool star varied between M5III and M7III. The spectral type was M5III during the phase of maximum activity of the system’s hot source, while the spectral type was M7III when the star’s optical radiation was almost completely absent. The luminosity of the cool giant varied from (6300–9100)L _⊙; its radius varied by approximately 30%. The ratio of the luminosities of the dust envelope and the cool giant varied from 0.08 to 0.5; i.e., up to 50% of the cool star’s radiation could be absorbed in the envelope. The temperature of dust particles in the emitting envelope varied from 550 to 750 K; the radius of the envelope varied by more than a factor of 2. The expansion of the emitting dust envelope observed in 1979–1988 accelerated: its initial velocity (in 1979) was ～8 km/s, while the maximum velocity (in 1987–1989) was ～180 km/s. Beginning in 1988, the radiation radius of the dust envelope began to decrease, first at ～45 km/s and then (in 1996–1998) at ～3 km/s. From 1979 until 1996, the mass of the emitting dust envelope increased by approximately a factor of 27 (the masses in 1979 and 1988 were ～1.4×10^?7 M _⊙ and ～3.8×10^?6 M _⊙, respectively), after which (by 1999) it decreased by nearly a factor of 7. The mass-loss rate of the cool star increased in 1979–1989, reaching ～3.5×10^?6 ～3.5×10^?6 M _⊙/yr in 1988. Subsequently (up to the summer of 1999), the envelope itself began to lose mass at a rate exceeding that of the cool star. The largest input of matter to the envelope occurred after the phase of optical activity in 1978–1985. If the envelope’s gas-to-dust ratio is ～100, the mass of matter ejected in 1988 was ～4×10^?4 M _⊙.     

Optical monitoring of the BL Lac object ON 231 in 1972–1990

The results of 19-year optical monitoring of ON 231 are presented. Photographic B-band observations were obtained during 123 nights from April 1972 to March 1990 as part of the quasar monitoring program carried out the Astronomical Institute of St. Petersburg State University. The new combined B-band light curve for ON 231 (1892–1999) is appreciably improved by our data, enabling us to identify a number of previously undetected high-amplitude events with time scales of weeks to months. On two nights, intraday variability with amplitudes \( \sim 0\mathop .\limits^m 8 - 0\mathop .\limits^m 9\) was observed. A number of conclusions are drawn about variability components with time scales from hours to decades. There are cases when very similar behavior on time scales from several weeks to several months was observed in the presence of substantially different base brightness levels. Both the amplitudes (\( \sim 1\mathop .\limits^m 5\)) and the characteristic shapes and overall durations of these events were the same. The constancy of the amplitudes of these events in magnitudes (i.e., the proportionality of the luminosity in rapid outbursts to the underlying level of the slowly varying component) can be explained in models that associate the variability with changes in the Doppler boosting factor due to variations in the inclination of the relativistic jet to the line of sight, if the slow and rapid components of the optical variability are associated with a steady component of the relativistic jet and shock waves (superluminal components) moving in the jet, respectively. Evidence for such a connection has been found for several superluminal sources. At the same time, there is evidence that in typical IDV events for ON 231, with durations of ～1.5–2 hr, the amplitudes depend on the base brightness level of the objects, suggesting that the IDV events and less rapid components of the variability have different natures and/or occur in different locations in the source.     

Satellite-based assessment of large-scale land cover change in Asian arid regions in the period of 2001–2009

Arid regions in Asia are commonly characterized by rapidly growing populations with limited land resources and varying rainfall frequencies under climatic change. Despite being one of the most important environmental challenges in Asia, the changing aridity in this region, particularly due to large-scale land cover change, has not been well documented. In this study, we used rainfall data and a new land heterogeneity index to identify recent trend in land cover changes in the Asian arid regions. The result indicates a significant decreasing trend of barren lands and an increasing trend of vegetated lands. Although the potential land cover change is commonly believed to be strongly sensitive to rainfall change, such sensitivity has not been observed during the nine-year period (2001–2009) analyzed. Through the analyses of two separate periods (2001–2005 and 2005–2009), the sensitivity of rainfall to land cover change in arid regions is found to be dependent on the initial spatial heterogeneity of vegetated land cover. The approach used and the findings in this study represent an important step toward better understanding of large-scale land cover change in the Asian arid regions, and have the potential to predict future land cover change under various climate change scenarios.     

Infrared and Raman spectroscopy studies of the α–β phase transition in cristobalite

Infrared and Raman spectra of cristobalite are presented as a function of temperature through the phase transition. The modes are assigned and the assignments compared to those of earlier workers. The compatibility of modes at the G-point of the a-phase with the X and G-points of the ß-phase is given. In the transition region of ca. 500–550 K, smooth changes in intensity, frequency and linewidths are seen in many modes, indicative of coexistence of a- and ß-forms.     

Inter-metropolitan migration of the newly landed immigrants in Canada: 1991–1996 and 1996–2001

Based on the tabulations of the Longitudinal Immigration Data Base, I characterized, explained and compared the 1991–1996 and 1996–2001 inter-metropolitan migration of the newly landed immigrants in Canada. The spatial and temporal patterns were consistent with the neoclassical economic theory and the ethnic enclave theory. In making their decisions on departure and destination choices, the immigrants were responsive to income and employment incentives, as well as the retaining and attracting powers of ethnic communities among Census Metropolitan Areas (CMAs). The research also discovered an interesting temporal pattern—while the inter-CMA migration of immigrants accentuated the over representation of the immigrants in Toronto and Vancouver in the 1991–1996 period, the rise of the “secondary” CMAs led to a spatial dispersal of the immigrants in the 1996–2001 period. This finding supplements the existing literature on internal migration of Canadian immigrants, which discovered little evidence of an increased dispersion of immigrants over time.     

Epicentre maps of the Mediterranean area (1901–1985)

The earthquake catalogue of the European area, 1901–1985, with unified magnitudes, has been used for the preparation of epicentre maps of the Mediterranean area. Epicentres have been plotted on three sheets for different magnitude ranges,M _B (orm _B ) 5, 0,M _S (orm _B ) = 4.4–4.9,M _S (orm _B ) 4.3, according to the estimated levels of homogeneity. The first map (M 5) enables an objective comparison of seismicity over the whole Mediterranean area. The other two maps are complementary without the guarantee of completeness. Epicentres define the position of principal earthquake zones and levels of earthquake activity. The maps also serve as the starting point for further data processing. Graphs illustrating the time variation of earthquake activity in the whole area and the mean magnitude-frequency relationships are included.     

N–S crustal shear system in the Bundelkhand massif: A unique crustal evolution signature in the northern Indian peninsula

The Bundelkhand massif, located in the northern part of the Indian shield, is a poly-deformed and poly-metamorphic terrain. This paper reports a new shear system developed throughout the massif in the form of N–S trending quartz veins that are sometimes quartzo-feldspathic and rarely granitic in composition. The veins are vertical and commonly occur in conjugate sets. This tectono-magmatic event appears to represent the youngest shear system of the massif as it cross-cuts all the earlier shear systems (E–W, NE–SE and NW–SE). Emplacement of this N–S vein system may have taken place due to extensional processes that developed some cracks along which siliceous magma was vertically emplaced. The complete absence of signature of the N–S event from the surrounding sedimentary cover of Vindhyan Supergroup, Bijawar and Gwalior Groups suggests that this shear system is pre-tectonic to the nearly E–W trending passive basins developed at the margins of the Bundelkhand craton. Further, several workers have considered the Bundelkhand massif as a part of the Aravalli craton. However, due to the absence of N–S, as well as the other (i.e., E–W, NW–SE and NW–SE), tectonic fabrics of the Bundelkhand massif in other cratons of the Peninsular India, and vice versa, makes the Bundelkhand block a separate and unique craton of its own and is not part of the Aravalli craton.     

Heavy metal contamination in the vicinity of the Daduk Au–Ag–Pb–Zn mine in Korea

The heavy metal contamination and seasonal variation of the metals in soils, plants and waters in the vicinity of an abandoned metalliferous mine in Korea were studied. Elevated levels of Cd, Cu, Pb and Zn were found in tailings with averages of 8.57, 481, 4,450 and 753 mg/kg, respectively. These metals are continuously dispersed downstream and downslope from the tailings by clastic movement through wind and water. Thus, significant levels of the elements in waters and sediments were found up to 3.3 km downstream from the mining site, especially for Cd and Zn. Enriched concentrations of heavy metals were also found in various plants grown in the vicinity of the mining area, and the metal concentrations in plants increased with those in soils. In a study of seasonal variation on the heavy metals in paddy fields, relatively high concentrations of heavy metals were found in rice leaves and stalks grown under oxidizing conditions rather than a reducing environment (P<0.05).     

Regional Population and Employment Change in Australia 1991–2001: Inertia in the Face of Rapid Change?

Analyses of the patterns of national population change have been influenced by the US experience where major differences between a older north and a newer south are prominent in many studies. The current paper argues that these perspectives overlook some inertia in the pattern of population and jobs. Drawing upon US and European experience the paper explores the pattern of change in Australia. There it finds that population has favoured newer locations but that gains in share of national population have not been large. At the same time some of the older regions have maintained population share, or at worst recorded small declines. That broad insight is enriched by sectoral analysis where it is clear that only the retail sector has experienced the large gains in new regions; employment change in other sectors showed the links with population change are weak. The paper concludes that simple notions of new region population and employment gains are oversimplified and overlook the substantial development around established centres. In particular it is possible that the old regions are re-structuring their spatial form and spilling over statistical boundaries and so actually maintaining established role in national networks.     

Long-Term Variability of Nutrients and Chlorophyll in the Chesapeake Bay: A Retrospective Analysis, 1985–2008

A retrospective analysis of freshwater discharge, riverine dissolved nutrient loads, dissolved nutrients, and chlorophyll in the Chesapeake Bay from 1985 to 2008 is presented. It is evident that each field displays an interannual variability averaged over the Bay. The N and P loads peaked in 1997 and have fluctuated with a decreasing trend since early 2004. Dissolved nutrient concentrations in the Bay appear to be largely controlled by riverine nutrient loads. The temporal variability of chlorophyll is positively correlated with nutrient loads and concentrations. Over the study period, N:P (DIN:DIP) molar ratios were consistently higher than the Redfield ratio (N:P?=?16:1) and strongly correlated with river discharge (R ²?=?0.68, p??16:1), and N is the limiting nutrient in summer and early autumn (N:P?4 from anoxic sediments. Long-term climate indices, such as El Niño Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO), appear to exert only a moderate control over the riverine discharge to the Bay or over the ecosystem response in terms of chlorophyll in the Bay. While not all related mechanisms can be inferred from available data, this analysis should help in determining future data needs for monitoring water quality and human and climate influence on the health of the Bay.     

Anoxia in the Domanik basin of the Timan–Pechora region

Analysis of the carbon isotopic composition in aryl carotenoid derivatives, including isorenieratene, in bitumen from domanikoid rocks of the sections cropping out along the Chut River revealed that they contain anomalously heavy carbon, which is determined by the formation of these compounds from green sulfur bacteria of the family Chlorobiaceae. These bacteria use the peculiar process of carbon fixing as HCO₃^? in the reversed tricarboxilic acid cycle. The fact of hydrosulfuric contamination of the photic water layer in the Domanik basin is confirmed by the plurality of data. Anoxity in shelf water of the middle Frasnian Timan–Pechora basin is evident from lithological features such as, for example, lamination of some rocks and mass death of the fauna.     

Theoretical Analyses of the Infrared Spectrum of Baiyuneboite—（Ce）

Baiyuneboite-(Ce) is a new fluor-carbonate mineral.Based on the fine data on the structure of the mineral,the factor group and normal coordinate analyses for its infrared spectrum have been carried out.The factor group analyses indicate that the site group and factor group splittings of the internal vibration bands of CO3^2- ions do not occur and that the double bands of normal modes result from two non-equal sets of CO3^2- ions in the crystal structure,The normal coordinate analyses give the stretching force constants.bend force constants and calculated frequencies of CO3^2- ions.The calculations of potential energy distribution allow us to assign v3 and v4 to the stretching vibration and the bend vibration of CO3^2- ions.respectively.     

Phlogopite Formation in the Orthopyroxene–Garnet System in the Presence of H2O–KCl Fluid in Application to the Processes of Mantle Metasomatism

Doklady Earth Sciences - The results of experimental studies are presented for reactions in the orthopyroxene–garnet–phlogopite system in the presence of H2O–KCl fluid at...     

Application of the region–time–length algorithm to study of earthquake precursors in the Thailand–Laos–Myanmar borders

In order to examine the precursory seismic quiescence of upcoming hazardous earthquakes, the seismicity data available in the vicinity of the Thailand–Laos–Myanmar borders was analyzed using the Region–Time–Length (RTL) algorithm based statistical technique. The utilized earthquake data were obtained from the International Seismological Centre. Thereafter, the homogeneity and completeness of the catalogue were improved. After performing iterative tests with different values of the \(r_{0}\) and \(t_{0}\) parameters, those of \(r_{0}\) = 120 km and \(t_{0}\) = 2 yr yielded reasonable estimates of the anomalous RTL scores, in both temporal variation and spatial distribution, of a few years prior to five out of eight strong-to-major recognized earthquakes. Statistical evaluation of both the correlation coefficient and stochastic process for the RTL were checked and revealed that the RTL score obtained here excluded artificial or random phenomena. Therefore, the prospective earthquake sources mentioned here should be recognized and effective mitigation plans should be provided.     

Activity of the Seyfert galaxy NGC 4151 in the near-IR in 1994–2011

We present the results of our infrared J H K L photometry of the Seyfert galaxy NGC 4151 during its active period in 1995–2011. The variable IR source was still in its active state in 2011, though its observed luminosity had almost halved compared to the maximum of 1995–1996. If the “cool” component of the galaxy’s variable source is a dust shell heated with the central “hot” source, its optical depth at 1.25 µm varied from 0.3 to almost 1.0, its temperature from 700 to 950 K, its size from 20 to 40 pc, and its mass from 2 to 40M _⊙ during our observations. A component with a period of 317 ± 5 days can be revealed in the flux variations observed in 1994–2011.     

Evolution of radiolarians in the late Albian–Campanian

The dynamics of radiolarian evolution in the late Albian–Campanian is analyzed, and several stages are recognized. The first stage (late Albian–middle Cenomanian), related to the MCE regional anoxic event, showed low evolutionary tempos and hence lacked structural change in radiolarian communities. The second stage (late Cenomanian–early Turonian), corresponding to ОАЕ 2, which was a global anoxic event, is characterized by a decrease in the number of genera, while many genera showed increased diversification of species composition. At this stage, a considerable number of genera became extinct and appeared, suggesting an increased rate of the radiolarian evolution. The third stage (middle Turonian–early Coniacian), including the beginning of ОАЕ 3, is characterized by a stabilized number of genera. The fourth stage (late Coniacian–Santonian) completely encompasses ОАЕ 3 except for its very beginning. At this stage, the radiolarian communities underwent a significant structural change, while their rate of evolution increased considerably. Nevertheless, during the ОАЕ 3 stage, a distinct trend toward a decrease in generic diversity continued from the late Cenomanian to the middle Turonian. The fifth stage (Campanian) is characterized by quite significant changes in the assemblage composition, while the trend toward a gradual decrease in the number of genera steadily continued. At this stage, which coincided with a considerable cooling, twice as many genera became extinct as during ОАЕ 2. The analysis of the dynamics of radiolarian evolution showed that the anoxic MCE, ОАЕ 2, and ОАЕ 3 events did not result in degradation of radiolarian assemblages. This suggests that this group has significant stratigraphic potential. In general, the evolution of radiolarians in the Late Cretaceous was gradual. By the end of the Campanian, nearly half of the generic diversity was composed of genera which appeared at the beginning of the Cretaceous and earlier.     

Minerals of the Fe–Ni–Co–Cu–S System in Picrite Intrusions of the Southern Urals: Signatures of Liquation and Differentiation of the Sulfide Melt

Doklady Earth Sciences - New data on the minerals of the Fe–Ni–Co–Cu–S system in the differentiated intrusions of the Southern Urals are presented. Based on a detailed study...     

Geodynamics of the Active Margin of Northeast Asia in the Late Cretaceous–Paleogene

Geotectonics - Late Cretaceous to Paleogene suprasubduction systems of Northeast Asia’s active margin are considered in order to determine key objects for the analysis of the geodynamic...