Spectral Variations in Early-Type Galaxies as a Function of Mass

We report on the strengths of three spectral indicators - Mg_2, Hbeta, and Hn/Fe - in the integrated light of a sample of 100 field and cluster E/S0 galaxies. The measured indices are sensitive to age and/or and metallicity variations within the galaxy sample. Using linear regression analysis for data with non-uniform errors, we determine the intrinsic scatter present among the spectral indices of our galaxy sample as a function of internal velocity dispersion. Our analysis indicates that there is significantly more intrinsic scatter in the two Balmer line indices than in the Mg_2 index, indicating that the Balmer indices provide more dynamic range in determining the age of a stellar population than does the Mg_2 index. Furthermore, the scatter is much larger for the low velocity dispersion galaxies, indicating that star formation has occurred more recently in the lower mass galaxies.Comment: 4 pages, 1 figure, 1 table, to appear in the Astrophysical Journal Letter

Social network analysis in operations and supply chain management: A review and revised research agenda

Purpose Social network analysis (SNA) seeks to manage the connections between entities through investigating and understanding behaviours and relationships. This study demonstrates the increasing relevance of social network approaches to solving contemporary and looming operations management (OM) and supply chain management (SCM) problems; including the coordination operations challenges raised by increased connectivity. Design/methodology/approach The systematic literature review approach adopted here examines 63 papers in OM and SCM published between 2000 and 2019. To-date OM reviews on SNA have focussed on discussing archetypal supply chains, what differentiates this study is the focus on how value was created in other forms of chains and operations. Findings This study reveals that current SNA adoption in OM is dominated by a manufacturing style focus on linear, sequential value creation, with a resulting focus only on sequential interdependence. SNA studies on reciprocally co-ordinated value creation (e.g. many service and network operations) are shown to have been neglected and are linked to a new agenda on contemporary management issues. Research limitations/implications Beyond encouraging the use of SNA, this study seeks to re-orient SNA approaches towards how contemporary services and networks create value. Originality/value Through adopting a unique combination of approaches and frameworks, this study challenges extant work to offer a substantially revised agenda for SNA use in Operations and Supply Chain Management

Symbiotic stars in the Local Group of Galaxies

Preliminary results of the ongoing search for symbiotic binary stars in the Local Group of Galaxies are presented and discussed.Comment: Proceedings of Physics of Evolved Stars 2015: A Conference Dedicated to the Memory of Olivier Chesneau, Nice, 8-12 June 201

Soil Characteristics of Four Juncus roemerianus Populations in Mississippi

The physical and chemical characteristics of soil from four widely separated Juncus roemerianus populations in Mississippi tidal marshes are determined. The J. roemerianus populations studied are located in Grand Bayou, Salt Flats, Weeks Bayou,and Belle Fantaine marshes. Organic matter, pH, CEC, N, P, K, Ca, S, Mg, and Zn analyses are based on composite soil samples. The percentage of sand, silt, and clay of the marsh soils is determined along with soil water content from the four locations. Statistical analysis indicates which marshes are different for each soil characteristic tested. No appreciable amounts of organic matter are present in the soils from Grand Bayou and the Salt Flats, however, the soils of Weeks Bayou and Belle Fontaine marsh are highly organic. Magnesium is significantly different among all locations. Concentrations of P are greatest in the marsh sails from Grand Bayou and lowest in the Salt Flats. Greater values are recorded for organic matter, CEC, N, K, Ca, S, Mg, and Zn in the Weeks Bayou and Belle Fontaine marsh soils than are recorded for the sails at Grand Bayou and Salt Flats. The results of the soil analyses show that tidal marsh soils vary considerably in physical and chemical characteristics among locations, and J. roemerianus is able to grow well in a variety of soil types

Growth Kinetics and Longevity of the Salt Marsh Rush Juncus roemerianus

Vegetative development of shoots of the tidal marsh rush Juncus roemerianus was studied quantitatively in short (S) , medium (M), and tall-leaved (T) populations. Shoot longevity varied between populations, with some shoots producing one leaf and living 4 months, while others produced seven leaves and lived over 4 years. An equation was developed from plastochron and leaf-age determinations to estimate shoot age in each population studied. Major morphological events common to all populations were (1) cessation of growth of the first leaf produced on an erect stem when growth of the second leaf was initiated, and (2) death of the leaf from the tip downward. Although the time period was variable, growth rates of leaves equalled their death rates in each population during maximum periods of growth and subsequent decline. While growth and death rates were similar between two of the populations (M, T) investigated, these rates were vastly different from those representative of the third population (S). Growth and death kinetics for leaves on individual shoots involved cyclic phenomena represented by a series of greatly overlapping harmonic curves. Each shoot reached a maximum carrying capacity expressed as linear biomass. Although living portions were often distributed over three or four leaves, the total equated to two mature living leaves for the medium (M) and tall-leaved (T) populations. In the short-leaved population (S) , the maximum amount of biomass attained by a single shoot during its life span equalled that of one mature leaf. A peculiar steady-state or homeostasis in growth and net productivity exists in each population. Short-lived shoots in the short-leaved population (S) was shown to have a rapid turnover of replacement rate, which is responsible for a high net productivity equal to or exceeding the net productivity of both the medium and tall-leaved populations. Although the cause of variation in basic growth pattems between the three populations was not investigated, both genetic and environmental factors may be involved

Effect of Mineral Deficiency on the Growth of the Salt Marsh Rush Juncus roemerianus

Plants of the salt marsh rush Juncus roemerianus were grown in deficient and complete nutrient solutions, and the growth responses were compared qualitatively and quantitatively. Plants grown in solutions deficient in K, S, P, and Mg were similar in appearance, which exemplified severe growth retardation. Plants grown in solutions deficient in Ca, N, and Fe also were very similar in total growth response, but had much longer leaves, more shoots, and greater biomass than those grown in the K, S, P, and Mg deficient solutions. Plants grown in complete nutrient solutions, with various sources of Fe, were very robust. Growth was better with FeCl3 than with FeEDTA. The most robust growth occurred in plants grown in the nutrient medium deficient in micronutrients (B, Mn, Zn, Cu, Mo), indicating that J. roemerianus is very sensitive to specific or certain combined micronutrients or concentrations generally recommended for terrestrial, especially agricultural, plants. The qualitative and quantitative symptoms, such as color, length, and abundance of leaves and roots as a response to deficiency of specific elements, were similar to those deficiency symptoms previously described for numerous terrestrial plants. However, a deficiency of certain nutrients such as S and Mg has a much greater effect on J. roemerianus than is generally shown for terrestrial plants

Soil Characteristics of Spartina alterniflora, Spartina patens, Juncus roemerianus, Scirpus olneyi, and Distichlis spicata Populations at One Locality in Mississippi

Soil characteristics from five adjacent monotypic zones or different populations of tidal marsh plants are determined. Populations of Spartina alterniflora, Spartina patens, Juncus roemerianus, Scirpus olneyi, and Distichlis spicata located in Graveline Bay marsh, Mississippi, are studied. Slight elevational differences between the plant populations exist. The aerial biomass for each plant population is different based on seasonal determinations. Soil pH, organic matter, N, P, K, S, Zn, Ca, and Mg concentrations are based on analyses of seasonal composite soil samples. Analyses of soil water samples are used to determine water content, salinity, PO4, and NH3. The soil characteristics are highly variable within and among populations. Some soil properties are significantly different, while others are not. These results reflect the complex patterns in the physical and chemical soil characteristics among the salt marsh plant populations studied; however, they may not completely account for the differences in standing crop or the sharp delineation between plant zones

Effect of Mineral Deficiency on the Growth of the Salt Marsh Rush Juncus roemerianus

Plants of the salt marsh rush Juncus roemerianus were grown in deficient and complete nutrient solutions, and the growth responses were compared qualitatively and quantitatively. Plants grown in solutions deficient in K, S, P, and Mg were similar in appearance, which exemplified severe growth retardation. Plants grown in solutions deficient in Ca, N, and Fe also were very similar in total growth response, but had much longer leaves, more shoots, and greater biomass than those grown in the K, S, P, and Mg deficient solutions. Plants grown in complete nutrient solutions, with various sources of Fe, were very robust. Growth was better with FeCl3 than with FeEDTA. The most robust growth occurred in plants grown in the nutrient medium deficient in micronutrients (B, Mn, Zn, Cu, Mo), indicating that J. roemerianus is very sensitive to specific or certain combined micronutrients or concentrations generally recommended for terrestrial, especially agricultural, plants. The qualitative and quantitative symptoms, such as color, length, and abundance of leaves and roots as a response to deficiency of specific elements, were similar to those deficiency symptoms previously described for numerous terrestrial plants. However, a deficiency of certain nutrients such as S and Mg has a much greater effect on J. roemerianus than is generally shown for terrestrial plants

Large Extra Dimensions, Sterile neutrinos and Solar Neutrino Data

Solar, atmospheric and LSND neutrino oscillation results require a light sterile neutrino, $\nu_B$, which can exist in the bulk of extra dimensions. Solar $\nu_e$, confined to the brane, can oscillate in the vacuum to the zero mode of $\nu_B$ and via successive MSW transitions to Kaluza-Klein states of $\nu_B$. This new way to fit solar data is provided by both low and intermediate string scale models. From average rates seen in the three types of solar experiments, the Super-Kamiokande spectrum is predicted with 73% probability, but dips characteristic of the 0.06 mm extra dimension should be seen in the SNO spectrum.Comment: 4 pages, 2 figure