​Late Quaternary environmental changes recorded in the Danish marine molluscan faunas

Late Quaternary, marine deposits in Denmark have yielded 247 subfossil species of molluscs. The sites are presented, and comparisons are made between the subfossil mollusc assemblages and the 278 shell-bearing mollusc species presently living in the Danish seas. 184 species are common to the two groups. The 63 species no longer occurring around Denmark are used as indicators of changing environmental conditions, including temperature, salinity and depth, throughout the last 130 000 years. Seven modern faunal regional units are defined and considered: the Bælt, the Baltic, the Kattegat, the Limfjord, the North Sea and the Vendsyssel regions, and the Skagen area based on the Skagen III Well DGU File No. 1.287. The Late Quaternary, marine, shell-bearing molluscs, comprising 341 subfossil and recent species, are characterised from the point of view of climatic (i.e. Arctic, Subarctic, Boreal and Lusitanian) affinities and animal–sediment relationships. On this background the faunal and environmental evolution recorded in the 217 m long Skagen Well core is analysed and described. The mollusc assemblages in the Skagen sequence indicate a deeper-water facies during the Eemian, the Weichselian and the older Holocene in contrast to what hitherto was known in other parts of the Danish area during the Late Quaternary. For the Skagen Well the chronozones Preboreal/Boreal, Atlantic, Subboreal and Subatlantic can be identified by 14C dating. The environmental changes within the seven regions through the Late Quaternary are evaluated by depicting the molluscan communities encountered in the seven Late Quaternary stages together with remarks on studies of the neighbouring areas. By following the marine communities through the Late Quaternary in the light of the classical bottom communities sensu C.G.J. Petersen, it is demonstrated how facies have changed both through time and space within the Danish marine realm. The well-established, more temperate Eemian marine fauna was closely associated with shallow-water environments. The inferred climatic changes reflect an interglacial–glacial cycle. However, the climatically induced changes during the Holocene in the marine environment were small and overshadowed by the facies changes. Out of the 341 species recorded in this study, 140 occur in the Eemian, 36 in the Early/Middle Weichselian and 41 in the Late Weichselian. The Holocene fauna is represented by 183 species of shell-bearing molluscs, of which the first recorded occurrence of 148 species has been radiocarbon-dated

Competence of a Spray Passive Down-draft Evaporative Cooling (PDEC) System for Space Cooling

A spray PDEC system has been relatively less considered than other passive cooling strategies as one of the viable low-energy solutions in the cooling of buildings while having a great potential in energy savings. This study is intended to evaluate the capability of a spray PDEC system for space cooling. It comprises four simulation scenarios to see the system response and influence of indoor thermal environment when a spray PDEC system is adopted as a primary cooling system in two different climates. The simulation results show that a spray PDEC system causes a substantial variation in the indoor thermal environment and sensible cooling rates while substantiating significant energy savings

Significance of Parameters Affecting the Performance of a Passive Down-Draft Evaporative Cooling (PDEC) Tower with a Spray System

PDEC towers with spray systems are known to achieve substantial energy savings. Various parameters such as the wet-bulb depression, the tower height, and the wind speed have been known to be key factors affecting the performance of the system. To date, the significance of these parameters and other important factors have not been adequately treated in the literature. There also has been a lack of models that can successfully investigate potential benefits of the system under various conditions where this particular system could be applicable. To address these critical issues, this study performed a parametric analysis by using a FLUENT model validated against experimental data. It demonstrated the significance of individual parameters including water droplet sizes. As a result, practical design guidelines for important system parameters were presented. A statistical analysis was then used to formulate analytic models that account for all of the relationships found in this study between the parameters and the supply air conditions of the system. Two regression equations were formulated for predicting supply air temperature and velocity

Fuels Guide for Sagebrush and Pinyon-Juniper Treatments: 10 Years Post-Treatment

Increased woody plant dominance and degraded understory vegetation are important issues on rangelands in the Intermountain West. Land managers implement woody plant reduction treatments of sagebrush (Artemisia spp.), juniper (Juniperus spp.), and pinyon pine (Pinus spp.) to increase understory diversity and cover, restore wildlife habitat, increase forage, improve ecosystem functions, and reduce or manipulate fuels to increase ecosystem resilience to fire and resistance to invasive annual grasses. Woody plant reduction treatments alter fuel orientation, continuity, and loading, and therefore have important implications for wildfire behavior, effects, and management. Currently, there is a lack of knowledge of the longer-term implications of these treatments on fuel loads and vegetation structure. Using data collected as part of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP), this guide summarizes fuel loads, vegetation cover by functional group, and shrub and tree stem density 10 years after sagebrush and pinyon-juniper reduction treatments. The data was collected at 16 study sites in Washington, Oregon, California, Nevada, and Utah, and is summarized by treatment type, region, and groups or woodland development phases based on pre-treatment vegetation. These summarized data can be used by land managers and fire behavior specialists to quickly estimate fuel loads in older treatments or to predict fuel loads 10 years after a potential treatment. These fuel loading data can be used to create custom fuel beds to model fire behavior and effects

A Field Guide for Grasses and Grass-like Plants of Idaho

The purpose of this project is to develop a user-friendly field guide to grasses and grass-like plants in Idaho, specifically geared to those with limited background in botany. The guide will feature 60 Idaho grasses and grass-like plants, intended for K-16 educators and students, ranchers, land owners, recreationists, and nature enthusiasts, with accompanying K-12 lesson plans. In the form of both a printed book and an offline app for iPhones and Androids, the guide will include colorful images showing detailed characteristics and vegetative features of each grass, an easy-to-use dichotomous key, and information on each plant’s history, forage value, and fire resistance. This dual resource will meet the needs of land managers making economic decisions regarding livestock production and field treatments; university students in wildlife and range sciences conducting class exercises and field research; K-12 educators during field botany excursions, teaching the use of dichotomous keys, and ecosystem studies; and recreationists engaged in nature study. Both book and app will be distributed via the University of Idaho Rangeland Center and the Idaho Range Resource Commission

Micronutrient deficiency in children

Malnutrition increases morbidity and mortality and affects physical growth and development, some of these effects resulting from specific micronutrient deficiencies. While public health efforts must be targeted to improve dietary intakes in children through breast feeding and appropriate complementary feeding, there is a need for additional measures to increase the intake of certain micronutrients. Food-based approaches are regarded as the long-term strategy for improving nutrition, but for certain micronutrients, supplementation, be it to the general population or to high risk groups or as an adjunct to treatment must also be considered. Our understanding of the prevalence and consequences of iron, vitamin A and iodine deficiency in children and pregnant women has advanced considerably while there is still a need to generate more knowledge pertaining to many other micronutrients, including zinc, selenium and many of the B-vitamins. For iron and vitamin A, the challenge is to improve the delivery to target populations. For disease prevention and growth promotion, the need to deliver safe but effective amounts of micronutrients such as zinc to children and women of fertile age can be determined only after data on deficiency prevalence becomes available and the studies on mortality reduction following supplementation are completed. Individual or multiple micronutrients must be used as an adjunct to treatment of common infectious diseases and malnutrition only if the gains are substantial and the safety window sufficiently wide. The available data for zinc are promising with regard to the prevention of diarrhea and pneumonia. It should be emphasized that there must be no displacement of important treatment such as ORS in acute diarrhea by adjunct therapy such as zinc. Credible policy making requires description of not only the clinical effects but also the underlying biological mechanisms. As findings of experimental studies are not always feasible to extrapolate to humans, the biology of deficiency as well as excess of micronutrients in humans must continue to be investigated with vigour

Photometric and Spectroscopic Analysis of Cool White Dwarfs with Trigonometric Parallax Measurements

A photometric and spectroscopic analysis of 152 cool white dwarf stars is presented. The discovery of 7 new DA white dwarfs, 2 new DQ white dwarfs, 1 new magnetic white dwarf, and 3 weak magnetic white dwarf candidates, is reported, as well as 19 known or suspected double degenerates. The photometric energy distributions, the Halpha line profiles, and the trigonometric parallax measurements are combined and compared to model atmosphere calculations to determine the effective temperature and the radius of each object, and also to constrain the atmospheric composition. New evolutionary sequences with C/O cores with thin and thick hydrogen layers are used to derive masses and ages. We confirm the existence of a range in Teff between 5000 and 6000K where almost all white dwarfs have H-rich atmospheres. There is little evidence for mixed H/He dwarfs, with the exception of 2 He-rich DA stars, and 5 C2H white dwarfs which possibly have mixed H/He/C atmospheres. The DQ sequence terminates near 6500K, below which they are believed to turn into C2H stars. True DC stars slightly above this temperature are found to exhibit H-like energy distributions despite the lack of Halpha absorption. Attempts to interpret the chemical evolution show the problem to be complex. Convective mixing is necessary to account for the non-DA to DA ratio as a function of temperature. The presence of helium in cool DA stars, the existence of the non-DA gap, and the peculiar DC stars are also explained in terms of convective mixing, although our understanding of how this mechanism works needs to be revised. The oldest object in our sample is about 7.9 Gyr or 9.7 Gyr old depending on whether thin or thick hydrogen layer models are used. The mean mass of our sample is 0.65 +/- 0.20 Msun.Comment: Accepted by ApJ Suppl (~April 2001); 79 pages incl. 25 figure

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