Earthquake recurrence as a record breaking process

Extending the central concept of recurrence times for a point process to recurrent events in space-time allows us to characterize seismicity as a record breaking process using only spatiotemporal relations among events. Linking record breaking events with edges between nodes in a graph generates a complex dynamical network isolated from any length, time or magnitude scales set by the observer. For Southern California, the network of recurrences reveals new statistical features of seismicity with robust scaling laws. The rupture length and its scaling with magnitude emerges as a generic measure for distance between recurrent events. Further, the relative separations for subsequent records in space (or time) form a hierarchy with unexpected scaling properties

પશુપાલક ભરવાડ જાતિની મહિલાઓમાં આવેલ સામાજિક પરિવર્તનની પ્રક્રિયાનો અભ્યાસ

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Hydrological and biogeochemical cycling along the Greenland ice sheet margin

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2012Global warming has led to a significant increase in Greenland ice sheet (GrIS) melt and runoff since 1990, resulting in escalated export of fresh water and associated sediment to the surrounding North Atlantic and Arctic Oceans. Similar to alpine glacial systems, surface meltwater on ice sheet surface drains to the base (subglacial) where it joins a drainage system and can become chemically enriched from its origin as dilute snow- and ice-melt. In this thesis, I examine the interdependence of glacial hydrology and biogeochemical cycling in terms of export of carbon and iron from the Greenland ice sheet. I develop a new isotope mixing-model to quantify water source contributions to the bulk meltwater discharge draining a GrIS outlet glacier. Results illustrate (a) the new application of a naturally occurring radioisotope (radon-222) as a quantitative tracer for waters stored at the glacier bed, and (b) the seasonal evolution of the subglacial drainage network from a delayed-flow to a quick-flow system. Model results also provide the necessary hydrological context to interpret and quantify glacially-derived organic carbon and iron fluxes. I combine bulk- and molecular-level studies of subglacial organic carbon to show that GrIS discharge exports old (radiocarbon depleted), labile organic matter. Similar investigations of dissolved and particulate iron reveal that GrIS discharge may be a significant flux of labile iron to the North Atlantic Ocean during the summer meltseason. Both carbon and iron are subject to proglacial processing prior to export to the marine environment, and exhibit strong seasonal variability in correlation with the subglacial drainage evolution. Low, chemically concentrated fluxes characterize the spring discharge, whereas higher, chemically dilute fluxes typify the summer discharge. Collectively, this thesis provides some of the first descriptions and flux estimates of carbon and iron, key elements in ocean biogeochemical cycles, in GrIS meltwater runoff.This research was supported the WHOI Arctic Research Initiative (EBK, SBD, MAC), the National Science Foundation (EBK, SBD), NASA (SBD), a National Science and Engineering Research Council of Canada Postgraduate Doctoral Fellowship (MPB), an American Geophysical Union Horton Hydrology Award (MPB), the Ocean Ventures Fund (MPB), and the WHOI Climate Change Institute (MPB)

Evolution of chemical composition along river drainage networks

Surface water chemistry from a tropical and temperate rivers system was studied in order to understand the controls on longitudinal variation of stream chemistry. In the Rio Icacos-Blanco system in Puerto Rico, I examined changes in stream chemistry associated with a change in bedrock composition from intrusive quartz diorite (upstream) to volcaniclasitc material (downstream). Overall, after sea-salt correction, most solutes decreased consistently with distance downstream. The silica to alumina ratio, however, changed sharply with changes in the underlying bedrock. Other indices of weathering rates and processes showed strong similarities despite the change in bedrock. The dominance of silica, alkalinity, calcium and sodium (after sea-salt correction) in surface waters suggests that anorthite and albite are the dominant minerals within the entire basin, and they are weathering rapidly (silicon to Na + K ≥4) with the bisiallitization type of weathering (silica to alumina \u3e2). Human influences on river chemistry in the Icacos-Blanco system appear to be minor, as nutrients (N and P) show little change along the drainage network. Sampling of tributaries and source points at high and low elevation within the uniform intrusive bedrock of the Icacos was undertaken to identify spatial variability in weathering processes. Landslides are frequent in the basin, and expose fresh mineral surfaces to weathering. Concentrations of weathering products were inversely related to pCO2, suggesting that the availability of primary reactive minerals, rather than carbonic acid concentrations, limits weathering. In the temperate Bagmati drainage system in Kathmandu valley, Nepal, population density appears to be the most fundamental control on the chemistry of surface waters. Concentrations in the Bagmati were extraordinarily high for nitrogen and phosphorus, and both nutrients and major ions were found in proportions similar to those in raw domestic sewage. The contribution of chemical weathering processes to water quality of the Bagmati does not seem to be significant within the Kathmandu valley. Ammonium contributes almost all nitrogen in the total dissolved nitrogen and the concentration of nitrate is negligible, probably due to rapid denitrification and limited nitrification within the stream channel under relatively low oxygen conditions

IBM KELOMPOK TENAGA ADMININISTRASI DAN GURU SPN KALASEY TENTANG PEMBUATAN SURAT DALAM BAHASA INGGRIS

Mitra sasaran kegiatan pelatihan ini, yaitu tenaga administrasi dan guru Sekolah Pertanian Negeri (SPN) Provinsi Sulawesi Utara yang berlokasi di desa Kalasey I, kabupaten Minahasa. Sekolah ini merupakan salah satu sekolah kejuruan yang membutuhkan tenaga administrasi serta guru yang terampil salah satunya dalam menulis surat-surat resmi akademik. Seiring dengan perkembangan jaman dan teknologi, kebutuhan untuk berkorespondensi menggunakan Bahasa Inggris meningkat. Menjawab kebutuhan ini, maka tenaga administrasi dan guru diharapkan mempunyai keterampilan untuk menulis surat resmi menggunakan Bahasa Inggris. Tujuan kegiatan IbM pelatihan ini, yaitu meningkatkan keterampilan kelompok guru dan tenaga administrasi sehingga mereka mampu mengutarakan maksud dan tujuan dalam suatu konteks komunikasi secara tulisan/ surat. Tujuan khusus program, ini, yaitu menghasilkan keterampilan menulis surat dalam Bahasa Inggris sesuai dengan format, bentuk dan budaya menulis yang berlaku. Adapun metode pelaksanaan yang akan diterapkan pada program ini, yaitu pelatihan dengan memperkenalkan berbagai jenis teks surat, baik yang formal maupun informal; pendampingan; dan evaluasi. Prosedur kerja untuk mendukung ketiga aspek permasalahan, berturut-turut, yaitu observasi, pelatihan, evaluasi, luaran, dan pelaporan.Kata Kunci: Penulisan Surat Resmi, Surat formal berbahasa Inggris, Guru dan TenagaAdministrasi, SPN Kalase