Effect of baselevel change on floodplain and fan sediment storage and ephemeral tributary channel morphology, Navarro River, California

Managed baselevel lowering in tributaries that emerge from small canyons onto forested floodplains affects floodplain and fan sediment storage and small ephemeral tributary channel morphology in the Navarro River basin, Mendocino Country, California, USA. Numerous small tributaries (drainage areas up to several square kilometres) flow through culverts under Highway 128 across the forested floodplain of the Navarro River and one of its major tributaries, the North Fork. Excavation significantly deepened and widened these small tributaries upstream and downstream of culverts under the highway following the 1997 flood (recurrence interval 12 years), that inundated both the floodplain and the highway and culvert system. The excavation lowered the local baselevel of the tributary systems within the floodplain. This field study documents the effect of the lowered baselevel on floodplain and fan sediment storage and ephemeral tributary channel morphology. Excavation created defined channels in the floodplain where no channels previously existed. Additionally, the excavation and baselevel change created steps, or knickpoints, that migrated headward and incised the upstream tributary channels. Tributary incision decreases the sediment storage potential of the fan and floodplain and reduces the residence time for storage of fine sediment. A reduction in fine sediment residence time degrades downstream habitat for anadromous fish and other aquatic organisms in the Navarro River. Large wood influences floodplain and small tributary channel morphology by forming steps and increases sediment residence time by trapping sediment in forested tributary-fan-floodplain systems. Although this field investigation is specific to the Navarro River basin, our findings linking culvert maintenance excavation to geomorphic processes may be extended to other roads on forested floodplains in the Pacific Northwest or other systems with roads on floodplains

56Ni dredge-up in the type IIp Supernova 1995V

We present contemporary infrared and optical spectra of the plateau type II SN 1995V in NGC 1087 covering four epochs, approximately 22 to 84 days after shock breakout. The data show, for the first time, the infrared spectroscopic evolution during the plateau phase of a typical type II event. In the optical region P Cygni lines of the Balmer series and of metals lines were identified. The infrared (IR) spectra were largely dominated by the continuum, but P Cygni Paschen lines and Brackett gamma lines were also clearly seen. The other prominent IR features are confined to wavelengths blueward of 11000 \AA and include Sr II 10327, Fe II 10547, C I 10695 and He I 10830 \AA. We demonstrate the presence of He I 10830 \AA on days 69 and 85. The presence of this line at such late times implies re-ionisation. A likely re-ionising mechanism is gamma-ray deposition following the radioactive decay of 56Ni. We examine this mechanism by constructing a spectral model for the He I 10830 \AA line based on explosion model s15s7b2f of Weaver & Woosley (1993). We find that this does not generate the observed line owing to the confinement of the 56Ni to the central zones of the ejecta. In order to reproduce the He I line, it was necessary to introduce additional upward mixing of the 56Ni, with 10^{-5} of the total nickel mass reaching above the helium photosphere. In addition, we argue that the He I line-formation region is likely to have been in the form of pure helium clumps in the hydrogen envelope.Comment: Accepted for publication in MNRAS, 32 pages including 11 figures (uses psfig.sty - included

Association between lung function and exacerbation frequency in patients with COPD

To quantify the relationship between severity of chronic obstructive pulmonary disease (COPD) as expressed by Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage and the annual exacerbation frequency in patients with COPD. We performed a systematic literature review to identify randomized controlled trials and cohort studies reporting the exacerbation frequency in COPD patients receiving usual care or placebo. Annual frequencies were determined for total exacerbations defined by an increased use of health care (event-based), total exacerbations defined by an increase of symptoms, and severe exacerbations defined by a hospitalization. The association between the mean forced expiratory volume in one second (FEV(1))% predicted of study populations and the exacerbation frequencies was estimated using weighted log linear regression with random effects. The regression equations were applied to the mean FEV(1)% predicted for each GOLD stage to estimate the frequency per stage. Thirty-seven relevant studies were found, with 43 reports of total exacerbation frequency (event-based, n = 19; symptom-based, n = 24) and 14 reports of frequency of severe exacerbations. Annual event-based exacerbation frequencies per GOLD stage were estimated at 0.82 (95% confidence interval 0.46-1.49) for mild, 1.17 (0.93-1.50) for moderate, 1.61 (1.51-1.74) for severe, and 2.10 (1.51-2.94) for very severe COPD. Annual symptom-based frequencies were 1.15 (95% confidence interval 0.67-2.07), 1.44 (1.14-1.87), 1.76 (1.70-1.88), and 2.09 (1.57-2.82), respectively. For severe exacerbations, annual frequencies were 0.11 (95% confidence interval 0.02-0.56), 0.16 (0.07-0.33), 0.22 (0.20-0.23), and 0.28 (0.14-0.63), respectively. Study duration or type of study (cohort versus trial) did not significantly affect the outcomes. This study provides an estimate of the exacerbation frequency per GOLD stage, which can be used for health economic and modeling purposes

Immuno flow cytometry in marine phytoplankton research

The developments in the combination of flow cytometry and immunology as a tool to identify, count and examine marine phytoplankton cells are reviewed. The concepts of immunology and flow cytometry are described. A distinction is made between quantitative and qualitative immunofluorescence. Quantitative immunofluorescence, the identification and enumeration of phytoplankton cells, is the research area that has advanced rapidly in the past decade, and is reviewed extensively. Key steps of quantitative immunofluorescence, fixation and immunolabel intensity, are discussed in more detail. Qualitative immunofluorescence is a new, hardly explored but highly interesting development in which qualitative -physiological- variables related to e.g. nutrient limitation or primary production are measured in individual cells instead of phytoplankton populations as a whole. Several combinations of immunological probes, both for species identification and for physiological measurements, are proposed. A special case of qualitative immunofluorescence is the measurement of phytoplankton toxins in single cells from natural populations. It is anticipated that the future use of semiconductor nanocrystals or quantum dots as fluorophores will greatly enhance signal detection in flow cytometry, and hence in both quantitative and qualitative immunofluorescence applications

An International Ultraviolet Explorer Archival Study of Dwarf Novae in Outburst

We present a synthetic spectral analysis of nearly the entire far ultraviolet International Ultraviolet Explorer (IUE) archive of spectra of dwarf novae in or near outburst. The study includes 46 systems of all dwarf nova subtypes both above and below the period gap. The spectra were uniformly analyzed using synthetic spectral codes for optically thick accretion disks and stellar photospheres along with the best-available distance measurements or estimates. We present newly estimated accretion rates and discuss the implications of our study for disk accretion physics and CV evolution.Comment: Accepted for publication in the ApJ, Part

Consumers discard a lot more food than widely believed: Estimates of global food waste using an energy gap approach and affluence elasticity of food waste

This work provides an internationally comparable consumer food waste dataset based on food availability, energy gap and consumer affluence. Such data can be used for constructing meaningful and internationally comparable metrics on food waste, such as those for Sustainable Development Goal 12. The data suggests that consumer food waste follows a linear-log relationship with consumer affluence and starts to emerge when consumers reach a threshold of approximately $6.70/day/capita level of expenditure. These findings also imply that most empirical models overestimate consumption by not accounting for the possibility of food waste in their analysis. The results also show that the most widely cited global estimate of food waste is underestimated by a factor greater than 2 (214 Kcal/day/capita versus 527 Kcal/day/capita). Comparison with estimates of US consumer food waste based on national survey data shows this approach can reasonably reproduce the results without needing extensive data from national surveys

A Far-Ultraviolet Spectroscopic Survey of Luminous Cool Stars

FUSE ultraviolet spectra of 8 giant and supergiant stars reveal that high temperature (3 X 10^5 K) atmospheres are common in luminous cool stars and extend across the color-magnitude diagram from Alpha Car (F0 II) to the cool giant Alpha Tau (K5 III). Emission present in these spectra includes chromospheric H-Lyman Beta, Fe II, C I, and transition region lines of C III, O VI, Si III, Si IV. Emission lines of Fe XVIII and Fe XIX signaling temperatures of ~10^7 K and coronal material are found in the most active stars, Beta Cet and 31 Com. A short-term flux variation, perhaps a flare, was detected in Beta Cet during our observation. Stellar surface fluxes of the emission of C III and O VI are correlated and decrease rapidly towards the cooler stars, reminiscent of the decay of magnetically-heated atmospheres. Profiles of the C III (977A) lines suggest that mass outflow is underway at T~80,000 K, and the winds are warm. Indications of outflow at higher temperatures (3 X 10^5K) are revealed by O VI asymmetries and the line widths themselves. High temperature species are absent in the M-supergiant Alpha Ori. Narrow fluorescent lines of Fe II appear in the spectra of many giants and supergiants, apparently pumped by H Lyman Alpha, and formed in extended atmospheres. Instrumental characteristics that affect cool star spectra are discussed.Comment: Accept for publication in The Astrophysical Journal; 22 pages of text, 23 figures and 8 table

HST Observations of Chromospheres in Metal Deficient Field Giants

HST high resolution spectra of metal-deficient field giants more than double the stars in previous studies, span about 3 magnitudes on the red giant branch, and sample an abundance range [Fe/H]= -1 to -3. These stars, in spite of their age and low metallicity, possess chromospheric fluxes of Mg II (2800 Angstrom) that are within a factor of 4 of Population I stars, and give signs of a dependence on the metal abundance at the lowest metallicities. The Mg II k-line widths depend on luminosity and correlate with metallicity. Line profile asymmetries reveal outflows that occur at lower luminosities (M_V = -0.8) than detected in Ca K and H-alpha lines in metal-poor giants, suggesting mass outflow occurs over a larger span of the red giant branch than previously thought, and confirming that the Mg II lines are good wind diagnostics. These results do not support a magnetically dominated chromosphere, but appear more consistent with some sort of hydrodynamic, or acoustic heating of the outer atmospheres.Comment: 36 pages, 12 figures, 7 tables, and accepted for publication in The Astronomical Journa