Flares From the Giant ar 9433 on 24 April 2001

We present H CCD observations of three small-to-medium-size two-ribbon flares observed in the giant AR 9433 on 24 April 2001. Flare observations at other associated wavelengths (e.g., soft X-rays (SXR), hard X-rays (HXR), microwaves (MW)) obtained from archives are also presented and compared. We have tested the Neupert effect for the most energetic third flare. The flare observations are in agreement with the thick-target model. In the case of this flare the HXR emitting electrons appears to be the heating source of SXR and H emissions. The flares are also studied in EUV and UV emissions using TRACE data. We discuss the complexity of the magnetic field using SOHO/MDI magnetograms. The flares are observed to occur in both (f/p) polarity regions in highly sheared magnetic field with emerging flux regions and MMFs.     

Stable hydrogen and oxygen isotope studies of rainfall and streamwaters for two contrasting holm oak areas of Catalonia, northeastern Spain

Results are presented of a study of stable hydrogen and oxygen isotopes in rainfall and streamwaters for the Montseny and Prades areas in northeastern Spain: results cover the full year of 1991. The isotopic pattern for rainfall is similar for both areas: there is a wide range in isotopic contents and the results show a strong, near-linear trend, δ²H = 7.9 × δ¹⁸O + 9.8 (N = 59; r² = 0.952), the ‘local meteoric line’. There is slight curvature to the data which may be related to the sources of water vapour forming the rainfall. Within the streams, the isotopic variability is much less than that of the rainfall although the data lie on, or very near to, the meteoric line. Data for detailed collections during storm events show more scatter than those collected regularly on a fortnightly basis. The event data show a linear feature that conforms to the local meteoric line. These results indicate that: (1) the main supply of water to the stream stormflow comes from water stored in the catchment prior to the event; (2) waters of more than one isotopic composition reside within the catchment and are transferable to the stream during storm events; (3) the main process of water transfer from the catchment back to the atmosphere comes from transpiration by the trees and (possibly) complete evaporation from the near-surface soil horizons and the tree canopy; (4) the isotopic technique cannot be used for quantitative hydrograph separation in this instance — at least two water types can be present within the catchment at any given time.     

Longitudinal variability of methane and ammonia bands on Saturn

A total of 129 spectra of the center of the disk of Saturn were obtained in March 1980 in order to search for possible longitudinal variations in the CH₄ 6190 and NH₃ 6450 bands. The spectra were reduced to reflectivities, and the band equivalent widths were measured using a blind, automated continuum fitting technique. The methane and ammonia equivalent widths are well correlated with each other. There are some latitude regions in which both bands show enhanced absorption and some latitudes in which both bands are weaker than the average. The continuum reflectivity is quite constant with latitude and shows no apparent correlation with molecular band equivalent width. These data were analyzed by adopting the model of J. C. Buriez and C. de Bergh (1981, Astron. Astrophys.94, 382–390) and using a doubling-adding radiative transfer code. The observed variations may be explained by a longitudinal variation in the altitude of the top of the thick cloud of about ±2 km from the mean.     

Low δ18O silicic volcanic rocks at the Calabozos caldera complex,southern Andes

Sr- and Pb-isotope data from the Calabozos center (⁸⁷Sr/⁸⁶Sr= 0.7043, ²⁰⁶Pb/²⁰⁴Pb=18.64–18.66, ²⁰⁷Pb/²⁰⁴Pb=15.59–15.60, ²⁰⁸Pb/²⁰⁴Pb=38.52–38.55) fall within the range of values reported for the southern volcanic zone (33–42° S) of the Andean arc. The range of ¹⁸O (5.0–6.3), however, includes unusually low values compared to volcanic rocks of similar bulk composition in the region. The Calabozos caldera complex lies at 35 °30 S, where the continental crust under the Andes thins southward from >45 to 30 km. Three voluminous late Pleistocene ashflow tuffs, collectively called the Loma Seca Tuff, constitute the bulk of >1,000 km³ of eruptive products at the Calabozos caldera complex and are evidence for a major, longlived andesitic-to-rhyodacitic magma reservoir at shallow crustal levels. The ¹⁸O values of the most evolved volcanic rocks from the Calabozos center are lower than predicted for rhyodacite produced by crystal fractionation from basalt typical of the region. Variation of ¹⁸O independent of bulk composition and inferred magmatic water contents indicates that the ¹⁸O depletion is a late-stage, upper-crustal phenomenon that cannot simply be attributed to magmatic interaction with meteoric water. The data are interpreted to be the result of assimilation of 5–30% of roof and wall rocks previously depleted in ¹⁸O by isotopic exchange in a meteoric hydrothermal system overlying the magma reservoir. Combined assimilation and fractional crystallization calculations applied to Sr isotope data show that the isotopic contrast between the Calabozos magmas and the assimilated rocks is very small. Hydrothermally-altered volcanic and plutonic rocks from the Tertiary Andean arc complex and Mesozoic-to-Cenozoic volcaniclastic sediments typical of the local basement provide a geologically reasonable contaminant compatible with the Sr- and O-isotope data. Pb-isotope data from the Calabozos system lend no significant insight into upper crustal contamination.     

Territoriality of signs: amber in the State’s semiotics in Latvia

Amber-signs in the Latvian nation-state’s semiotics, constructed during the interwar period, are only bits and pieces of a complex system such as the State. However, the resonance that amber semiotics effectuated, despite its actual rarity, was and still is remarkably influential. Amber was extensively deployed as a signifier to the territory and its people, places and things; it signified patria, belonging and the homeland. Such State semiotics, according to Deleuze–Guattarian concepts, is distinguished as a signifying regime of signs characterized by its universal deception and regulated by State-controlled interpretations, facialized centres, and a high degree of deterritorializations. We examine the thresholds of territoriality-deterritorialization relations and expressions of amber signs during the Latvian nation-state’s and the Soviet Union’s semiotic regimes, conceptualized as indexes, symbols and icons. By tracing and mapping of these territorialisation movements we enrich our understanding of how effective the created semiotics are, and in what variety of forms and territorialities, including linguistic, craftsmanship, and varied place makings, they are expressed in a particular regime. Such territorial perspective thus shifts the focus from what and why these signs mean (e.g., national identity, homeland) to where, when and how (e.g., dynamics of various State’s territorialities) they become operational. Among other national products that emit signs, amber proved to be most effective in the functioning of State’s signifying semiotics in Latvia, representing thoroughly the strangleholds and the continuity of such deceptive semiotics.     

Accumulation of hexavalent chromium by an exopolysaccharide producing marine Enterobacter cloaceae

An exopolysaccharide producing Enterobacter cloaceae (AK-I-MB-71a) was tested for its Cr (VI) tolerance. This isolate was not only resistant to this heavy metal but also showed enhanced growth and exopolysaccharide production in the presence of Cr (VI) at 25, 50 and 100 ppm concentrations. XRF analysis of both the biomass as well as the exopolysaccharide revealed that a sum total of about 60-70% chromium was accumulated by this bacterium. This indicated that this organism could prove to be a potential candidate in the field of bioremediation with respect to chromium removal.     

Conceptualization and implementation of ecosystems-based adaptation

While ecosystems-based adaptation (EbA) has been received with great interest, the requirements for EbA implementation and its precise benefits under future climate change are unclear. Furthermore, EbA’s overlap with environmental, and development policy agendas leads to ambiguity regarding what actions fall under the rubric of EbA. We analyze the projects identified by the UNFCCC as examples of EbA to understand how EbA is conceptualized and promoted by the international community. Addressing climate change is the primary objective of 58% of the EbA projects; the other 42% of projects provide adaptation benefits yet are not primarily driven by climate change. A project’s adaptation targeting is tied to its information needs. Projects whose primary objective is to address climate change are more likely to use detailed climate projections than projects whose primary objective is to address natural hazards, development or ecosystems degradation. A majority of projects do not address uncertainty in future climate change or in adaptation benefits, nor do they track adaptation outcomes. This prevalent lack of monitoring highlights the possibility of a gap between expected and realized adaptation outcomes. It also represents a lost opportunity for improving knowledge of the thresholds of effectiveness of EbA and of factors influencing EbA efficacy.     

Anthropogenic disturbance history influences the temporal coherence of paleoproductivity in two lakes

We investigated how the history of local disturbances in a watershed can influence the regional coherence of ecosystem properties in lakes that have similar morphometry and climatic conditions. We measured sedimentary δ¹³C, δ¹⁵N, C:N and %BSiO₂ in Sooke Lake Reservoir (SOL) and Shawnigan Lake (SHL), which are located within 4 km of each other on Vancouver Island, Canada. SOL is an impounded lake whose watershed has been fully protected over the last century, although the lake level has been raised 3 times via impoundment during this period. SHL has a similar limnological regime, but the surrounding watershed has been developed extensively for residential uses. We investigated how a pulse disturbance regime in SOL (i.e. repeated dam raising) and a press disturbance regime in SHL (i.e. persistent development) influenced the variability of paleoindicators in each system over time. We found that these contrasting disturbance regimes reduced the regional temporal coherence of aquatic productivity between the two lakes (indicated by %BSiO₂), but did not influence the regional coherence of nutrient status or the main carbon sources of the lakes (indicated by %C, %N and δ¹³C). In contrast, an indicator of the sources and cycling of nitrogen (δ¹⁵N) showed increased coherence. Local disturbances also affected the variability of the paleoindicators within each system over time. In SOL, impoundments led to both declines (%N, δ¹⁵N) and increases (δ¹³C) in the variability of paleoindicators. In SHL, persistent watershed development led to lower variability of two paleoindicators (%N, %BSiO₂). Overall, our data suggest that local disturbances can influence the %BSiO₂ and C:N ratio of lake sediments, but are less likely to alter the regional coherence of %C, %N and δ¹³C between lakes. Biplob Das and Anita Narwani contributed equally to this work.