Hyper-accumulation of legacy fallout radionuclides in cryoconite on Isfallsglaciären (Arctic Sweden) and their downstream distribution

The release of legacy fallout radionuclides (FRNs) in response to glacier retreat is a process that has received relatively little attention to date, yet may have important consequences as a source of secondary contamination as glaciers melt and down-waste in response to a warming climate. The prevalence of FRNs in glacier-fed catchments is poorly understood in comparison to other contaminants, yet there is now emerging evidence from multiple regions of the global cryosphere for substantially augmented FRN activities in cryoconite. Here we report concentrated FRNs in both cryoconite and proglacial sediments from the Isfallsglaciären catchment in Arctic Sweden. Activities of some FRNs in cryoconite are two orders of magnitude above those found elsewhere in the catchment, and above the activities found in other environmental matrices outside of nuclear exclusion zones. We also describe the presence of the short-lived cosmogenic radionuclide 7Be in cryoconite samples, highlighting the importance of meltwater-sediment interactions in radionuclide accumulation in the ice surface environment. The presence of fallout radionuclides in glaciers may have the potential to impact local environmental quality through both isolated hotspots of radioactivity caused by glacier down-wasting, and downstream transport of contaminants to the proglacial environment through interaction with sediments and meltwater. We thus recommend that future research in this field focusses on processes of accumulation of FRNs and other environmental contaminants in cryoconite, and whether these contaminants are present in quantities harmful for both local and downstream ecosystems.

Population estimate of wild rainbow trout in a remote stream of southern California

Recreational fishing for Rainbow Trout (Oncorhynchus mykiss) is important economically in California. We determined the upstream and downstream distribution of Rainbow Trout in a southern California stream, and classified all available habitat within that area as riffle, pool, cascade-pool-complex, and flatwater. Approximately 10% (based on length) of each habitat type was sampled using depletion electrofishing. We estimated Rainbow Trout abundance, both <100 mm and ≥100 mm, by extrapolating average number of fish per m² in each habitat type sampled to the total m² of each habitat type. A total of 854 fish were captured, with the greatest proportion coming from the cascade-pool-complex habitat type, followed by pool, flatwater, and riffle. The population estimate for Rainbow Trout <100 mm was 1,763 fish (95% CI ±442), and for Rainbow Trout ≥100 mm was 5,383 fish (95% CI ±1,688).

STUDI KELAYAKAN INVESTASI DAN TARIF UNTUK PEMBANGUNAN INFRASTRUKTUR UP STREAM DAN DOWN STREAM SPAM PEKANBARU 2015 – 2035

ABSTRAKInvestasi pada Sistem Penyediaan Air Minum (SPAM) meliputi kegiatan Upstream (unit air baku dan unit produksi) dan Downstream (unit distribusi dan unit pelayanan) memerlukan investasi yang besar sehingga membutuhkan analisis dan pertimbangan yang mendalam. Keterbatasan dana membuat pemerintah mendorong swasta untuk berinvestasi. Pemulihan investasi dan perolehan laba bagi investor terkait erat dengan tarif, serapan pasar dan dukungan pemerintah terhadap biaya konstruksi. Simulasi tarif, serapan pasar dan dukungan pemerintah terhadap biaya konstruksi menghasilkan variasi nilai Net Present Value (NPV). Variasi nilai NPV berfungsi dalam memberikan tawaran dan rekomendasi yang komunikatif bagi pemerintah dan swasta dalam memutuskan investasi dan tarif pembangunan infrastruktur upstream dan downstream SPAM Pekanbaru.Kata kunci : SPAM, upstream, downstream, investasi, tarif, NPV, serapan pasar, dukungan pemerintah.ABSTRACTInvestment in drinking water suplly system management (SPAM) includes upstream (water intake unit and production unit) and downstream (distribution unit and service unit) require substansial investment requiring deepanalysis and deliberation. Funding constraints prompted the goverment to encourage the private sector to invest. Recovery of investment and profitability for investor is closely related to tarrifs, market uptake and goverment support for construction costs. Tarrif simulation, market uptake and goverment support for construction costs result in variations Net Present Value (NPV). The variation of NPV serves to provides communicative offers and recomendations for private and goverments. In deciding investment and tarrifs on upstream and downstream SPAM Pekanbaru infrastructure development.Keywords : SPAM, upstream, downstream, investment, tarrif, market demand, govermentsupport.

Width dependent collisionless electron dynamics in the static fields of the shock ramp, 1, Single particle behavior and implications for downstream distribution

We study the collisionless dynamics of electrons in the shock ramp using the numerical trajectory analysis in the model electric and magnetic fields of the shock. Even with very modest assumptions about the cross-shock potential the electron trajectories are very sensitive to the width of the ramp. The character of electron motion changes from the fully adiabatic (with conservation of v2<perp> /B) when the ramp is wide, to the nonadiabatic one, when the ramp becomes sufficiently narrow. The downstream electron distribution also changes drastically, although this change depends on the initial electron temperature.