Variations in the oxygen three-isotope terrestrial fractionation line revealed by an inter-laboratory comparison of silicate mineral analyses

An inter-laboratory comparison of analytical results for the slopes of Terrestrial Fractionation Lines (TFL) measured on a group of quartz and a separate group of garnet samples shows good agreement between laboratories. However, the slopes of the TFL’s for each mineral group differ slightly

Graphite Vein Deposits of New Hampshire

Guidebook for field trips in southwestern New Hampshire, southeastern Vermont, and north-central Massachusetts: New England Intercollegiate Geological Conference, 80th annual meeting, October 14, 15 and 16, 1988, Keene, New Hampshire: Trip B-

Geochemistry of Pallasite Olivines and the Origin of Main-Group Pallasites

Main-group pallasites (PMG) are mixtures of iron-nickel metal and magnesian olivine thought to have been formed at the core-mantle boundary of an asteroid [1]. Some have anomalous metal compositions (PMG-am) and a few have atypically ferroan olivines (PMG-as) [2]. PMG metal is consistent with an origin as a late fractionate of the IIIAB iron core [2]. Most PMG olivines have very similar Fe/Mg ratios, likely due to subsolidus redox reaction with the metal [3]. In contrast, minor and trace elements show substantial variation, which may be explained by either: (i) PMG were formed at a range of depths in the parent asteroid; the element variations reflect variations in igneous evolution with depth, (ii) the pallasite parent asteroid was chemically heterogeneous; the heterogeneity partially survived igneous processing, or (iii) PMG represent the core-mantle boundaries of several distinct parent asteroids [4, 5]. We have continued doing major, minor and trace elements by EMPA and INAA on a wider suite of PMG olivines, and have begun doing precise oxygen isotope analyses to test these hypotheses. Manganese is homologous with Fe(2+), and can be used to distinguish between magmatic and redox processes as causes for Fe/Mg variations. PMG olivines have a range in molar 1000*Mn/Mg of 2.3-4.6 indicating substantial igneous fractionation in olivines with very similar Fe/Mg (0.138-0.148). The Mg-Mn-Fe distributions can be explained by a fractional crystallization-reduction model; higher Mn/Mg ratios reflect more evolved olivines while Fe/Mg is buffered by redox reactions with the metal. There is a positive association between Mn/Mg and Sc content that is consistent with igneous fractionation. However, most PMG olivines fall within a narrow Mn/Mg range (3.0-3.6), but these show a substantial range in Sc (1.00-2.29 micro-g/g). Assuming fractional crystallization, this Sc range could have resulted from approx.65% crystallization of an ultramafic magma. This is inconsistent with formation at the core-mantle boundary of a single asteroid [4]. One alternative is that the PMG are fragments of several asteroids, and these could have had different initial Sc contents, Mn/Mg and differences in igneous history. Our preliminary O isotope data and those of [6, 7] do not support this, although the coverage of PMG olivines is incomplete. The PMG-as Springwater is not easily fit in any scenario. Its olivine has among the highest Mn/Mg suggesting it is one of the most evolved, but the lowest Sc content suggesting it is the least evolved. The O isotopic composition of Springwater olivine is the same as that of other PMG. Thus there is no indication that it represents a distinct parent asteroid. Our preliminary O isotopic data favor a single PMG parent asteroid. In this case, the olivines are more likely melt-residues, and that the parent asteroid was initially heterogeneous in chemical, but not isotopic, composition

The JCMT Gould Belt Survey: radiative heating by OB stars

Radiative feedback can influence subsequent star formation. We quantify the heating from OB stars in the local star-forming regions in the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey. Dust temperatures are calculated from 450/850 μm flux ratios from SCUBA-2 observations at the JCMT assuming a fixed dust opacity spectral index β = 1.8. Mean dust temperatures are calculated for each submillimetre clump along with projected distances from the main OB star in the region. Temperature versus distance is fitted with a simple model of dust heating by the OB star radiation plus the interstellar radiation field and dust cooling through optically thin radiation. Classifying the heating sources by spectral type, O-type stars produce the greatest clump average temperature rises and largest heating extent, with temperatures of over 40 K and significant heating out to at least 2.4 pc. Early-type B stars (B4 and above) produce temperatures of over 20 K and significant heating over 0.4 pc. Late-type B stars show a marginal heating effect within 0.2 pc. For a given projected distance, there is a significant scatter in clump temperatures that is due to local heating by other luminous stars in the region, projection effects, or shadowing effects. Even in these local, ‘low-mass’ star-forming regions, radiative feedback is having an effect on parsec scales, with 24 per cent of the clumps heated to at least 3 K above the 15 K base temperature expected from heating by only the interstellar radiation field, and a mean dust temperature for heated clumps of 24 K

Guiding Diffusion among Local Food Clientele: Recommendations for Extension Programming

The demand for local food has risen dramatically over the last decade, and many states have created brands to promote products grown within that state. However, the effect of state brands on consumer perceptions remains unknown. Extension agents serve as change agents and a bridge between science and the public to purvey information for adoption decisions. This study sought to determine if differences existed between consumers’ perceptions of food labeled local and food labeled Fresh from Florida to inform Extension programming. Florida residents (N = 530) were surveyed utilizing a between-subjects experimental design. Respondents were asked questions about their attitudes, trust and transparency, and information preferences toward food labeled Fresh from Florida or local food, depending on the experimental treatment they received. Results of this study indicated that consumers shared similar perceptions of local and Fresh from Florida food, except for the belief that Fresh from Florida comes from larger farms, Fresh from Florida labeling is more trustworthy, and there is a greater desire to see a definition of Fresh from Florida food. When Extension agents develop programming on economic viability, information on local food and state brands should be included to help producers market their products and increase revenues

Discussing Extension Agents’ Role in Moderating Contentious Issue Conversations

Extension agents are finding themselves engaged in problem-solving roles as public needs adjust to a climate where issues facing the agricultural and natural resource industry are more often contentious than benign. As connectors between the Land-grant university system and the public, Extension agents need to know how to effectively communicate about contentious issues with clientele. This study used an online survey design to determine Extension agents’ attitudes toward contentious issues, challenges that they face, and effective means of communication. The findings revealed Extension agents’ attitudes toward communicating about contentious issues were more positive than negative. Additionally, they found the availability of misinformation and the complexity of contentious issues to be most challenging when communicating with clientele. One-on-one in-person, workshops, phone calls, and group meetings were identified as the most effective methods of communicating about contentious issues. Additional training and familiarization with current contentious issues were recommended. Future research should examine the contentious issues Extension agents are discussing, methods being used to facilitate conversations, the effect of contentious issues on job satisfaction, and the factors hindering Extension agents as they address contentious issues

The Wild Turkey in South Dakota

This bulletin provides an extensive look at the wild turkey in South Dakota

Communication of Genetic Modification Science: Consumers’ Critical Thinking Style, Perceived Transparency of Information, and Attitude

Consumers’ attitude toward GM science is not only an important factor to determine the industry’s development, it is also a crucial topic across various countries. How people express their judgment of GM science, involves a highly complicated process. Because of this complexity, influence on attitude toward GM science has become a popular research topic and has been examined through various variables. This study sought to examine the effects of critical thinking styles and perceived transparency of GM science on attitude toward GM science. To fulfill the purpose of the research, an online survey was conducted. A total of 1,047 adults across the United States were recruited using non-probability sampling techniques. The results of the study found critical thinking style had a significant impact on the perceived transparency of GM science information and attitude toward GM science. However, consumers with higher perceived transparency of GM science information reported lower attitudes toward GM science than those who had lower perceived transparency. An interaction effect of critical thinking styles and perceived transparency of GM science on attitude toward GM science was found. Further research examining perceived transparency was recommended. In addition, it was recommended that extension agents or agricultural communicators could develop various communication strategies based on various attribution of consumers

Do Pine Trees in Aspen Stands Increase Bird Diversity

In the Black Hills of South Dakota, quaking aspen (Populus tremuloides) is being replaced by conifers through fire suppression and successional processes. Al- though the Black Hills National forest is removing conifers (primarily ponderosa pine [Pinus ponderosa])toincreasetheaspencommunitiesinsomemixedstands,ForestPlan guidelines allow four conifers per hectare to remain to increase diversity in the remaining aspen stand. We compared bird species richness in pure ponderosa pine, mixed stands dominated by ponderosa pine with quaking aspen, mixed stands dominated by aspen with ponderosa pine, and pure aspen stands. Stands dominated by ponderosa pine had lower (