Looking for outflow and infall signatures in high mass star forming regions

(Context) Many physical parameters change with time in star forming regions. Here we attempt to correlate changes in infall and outflow motions in high mass star forming regions with evolutionary stage using JCMT observations. (Aims) From a sample of 45 high mass star forming regions in three phases of evolution, we investigate the presence of established infall and outflow tracers to determine whether there are any trends attributable to the age of the source. (Methods) We obtained JCMT observations of HCO+/H13CO+ J=4-3 to trace large scale infall, and SiO J=8-7 to trace recent outflow activity. We compare the infall and outflow detections to the evolutionary stage of the host source (high mass protostellar objects, hypercompact HII regions and ultracompact HII regions). We also note that the integrated intensity of SiO varies with the full width at half maximum of the H13CO+. (Results) We find a surprising lack of SiO detections in the middle stage (Hypercompact HII regions), which may be due to an observational bias. When SiO is detected, we find that the integrated intensity of the line increases with evolutionary stage. We also note that all of the sources with infall signatures onto Ultracompact HII regions have corresponding outflow signatures as well.Comment: 9 pages, 5 figures, 5 tables. Accepted by A&

Lipstick Stains

Abstract I wrote my poem “Lipstick Stains” for an assignment for my Writing Poetry class. We were told to look at a list of shapes and write out all of the ideas and images that the shapes brought to our minds. When looking at a certain shape, I was reminded of the shape of lips, leaves, pistachios, crab pincers, and kisses. The idea for the poem immediately came to me, and I based much of it on true experiences and memories from people in high school. Even the little plant cutting is real, growing only two leaves in a brown bowl in my apartment. I had always had a special sympathy for a girl I knew from high school who got pregnant. For some reason, I’ve always remembered her and wanted to be friends with her. This assignment was the perfect opportunity for me to write an inspirational poem that commemorates her bravery and vulnerability and her diminished idea of love

ALMA CO J=6-5 observations of IRAS16293-2422: Shocks and entrainment

Observations of higher-excited transitions of abundant molecules such as CO are important for determining where energy in the form of shocks is fed back into the parental envelope of forming stars. The nearby prototypical and protobinary low-mass hot core, IRAS16293-2422 (I16293) is ideal for such a study. The source was targeted with ALMA for science verification purposes in band 9, which includes CO J=6-5 (E_up/k_B ~ 116 K), at an unprecedented spatial resolution (~0.2", 25 AU). I16293 itself is composed of two sources, A and B, with a projected distance of 5". CO J=6-5 emission is detected throughout the region, particularly in small, arcsecond-sized hotspots, where the outflow interacts with the envelope. The observations only recover a fraction of the emission in the line wings when compared to data from single-dish telescopes, with a higher fraction of emission recovered at higher velocities. The very high angular resolution of these new data reveal that a bow shock from source A coincides, in the plane of the sky, with the position of source B. Source B, on the other hand, does not show current outflow activity. In this region, outflow entrainment takes place over large spatial scales, >~ 100 AU, and in small discrete knots. This unique dataset shows that the combination of a high-temperature tracer (e.g., CO J=6-5) and very high angular resolution observations is crucial for interpreting the structure of the warm inner environment of low-mass protostars.Comment: Accepted for publication in A&A Letter

Towards New Energy Infrastructures in Eurasia: A Background Paper

This study explores the concept of new energy infrastructures (in particular gas pipelines) in Eurasia and discusses its implications on future energy systems, gas trade, and the environment. Overall resource availability is not expected to be a real constraint in meeting growing energy demand within the next 100 years, but the geographical concentration of resources is. The expected increase in the use of domestic energy sources (coal) in Asia is associated with severe adverse environmental impacts causing significant damage to human health and the natural environment. In contrast, natural gas could offer an ideal bridge to the post fossil era, but requires the development of new Eurasian energy networks. Up-front investment in gas transit pipelines may constitute a significant portion of future energy investments. The financial risks appear significant and depend on factors such as demand and supply development, technological progress, geographical and political environments and prevailing regulatory regimes. Timely investment and associated cost reductions in the necessary infrastructure could create the potential for FSU gas exports becoming ten-fold as high in 2050 as otherwise would be the case. This would have significant positive impacts on the global, regional and local environment and also entail significant positive economic impacts. In addition, supply diversification would be promoted

Technological progress towards sustainable development

The purpose of this paper is twofold. First, to present an analysis of a comprehensive set of global energy scenarios that has been undertaken to identify key energy technologies for achieving sustainable development. Secondly, to describe tools that could aid policy makers using insights in the dynamics of technological progress to promote the development of promising technologies throughresearch and development (R&D) and procurement. As an operational working definition of sustainable development we use the following four criteria: (1) Economic growth sustains throughout the whole time horizon; (2) socio-economic inequity among world regions is reduced "significantly" during this century; (3) reserves-to-production (R/P) ratios of exhaustible primary energy carriers do not decrease substantially from today's values; and (4) short- to medium-term environmental impacts (e.g., acidification) are reduced towards meeting critical loads and carbon emissions at the end of the century are below today's levels. Applying these criteria in an analysis of a representative set of global economy-energy-environment scenarios shows that in sustainable-development scenarios, hydrogen fuel cells and solar photovoltaic cells emerge as key technologies in the long run. Natural gas technologies, in particular fuel cells and combined-cycle power plants, could provide for an efficient medium-term transition to these key technologies. The question then becomes which policies can promote the development of these technologies. We think that an important tool to tackle this question is provided by an improved concept of technological learning. According to that concept, technological progress, expressed as specific technology cost, is a regular function of not only cumulative installed capacity but also of R&D expenditures. This tool can assist in determining how much money should be spent for which energy technology on procurement (capacity expansion) and how much money for R&D. The results of first model runs aiming at eventually formulating policy guidance are presented

Gender-Divergent Profile of Bile Acid Homeostasis during Aging of Mice

Aging is a physiological process with a progressive decline of adaptation and functional capacity of the body. Bile acids (BAs) have been recognized as signaling molecules regulating the homeostasis of glucose, lipid, and energy. The current study characterizes the age-related changes of individual BA concentrations by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in serum and liver of male and female C57BL/6 mice from 3 to 27 months of age. Total BA concentrations in serum increased 340% from 3 to 27 months in female mice, whereas they remained relatively constant with age in male mice. During aging, male and female mice shared the following changes: (1) BA concentrations in liver remained relatively constant; (2) the proportions of beta-muricholic acid (βMCA) increased and deoxycholic acid (DCA) decreased between 3 and 27 months in serum and liver; and (3) total BAs in serum and liver became more hydrophilic between 3 and 27 months. In female mice, (1) the mRNAs of hepatic BA uptake transporters, the Na+/taurocholate cotransporting polypeptide (Ntcp) and the organic anion transporting polypeptide 1b2 (Oatp1b2), decreased after 12 months, and similar trends were observed for their proteins; (2) the mRNA of the rate-limiting enzyme for BA synthesis, cholesterol 7α-hydroxylase (Cyp7a1), increased from 3 to 9 months and remained high thereafter. However, in male mice, Ntcp, Oatp1b2, and Cyp7a1 mRNAs remained relatively constant with age. In summary, the current study shows gender-divergent profiles of BA concentrations and composition in serum and liver of mice during aging, which is likely due to the gender-divergent expression of BA transporters Ntcp and Oatp1b2 as well as the synthetic enzyme Cyp7a1

Factors affecting the site of investment, and the reliance on savings for arctic breeders : the capital–income dichotomy revisited

The extent to which migratory birds that breed in the Arctic and winter in southern biomes rely on residual body stores for reproduction is unresolved. The short arctic summer and the limited availability of food early in the season constrain the time available for successful reproduction. Birds that are able to bring sufficient endogenous reserves to the breeding ground to meet, at least partially, the demands of egg-laying can initiate clutch production soon after arrival, thereby shortening the length of the breeding season and improving the chances of reproductive success. The amount of reserves available will be influenced by body size, the increased energetic and predation costs associated with carrying large stores, distances between staging sites and the location of the breeding grounds within the Arctic. Birds need not fly directly to the breeding grounds from the established temperate staging sites. Extensive feeding by migrants may occur in the Arctic, even within a few kilometres of the breeding sites as the birds track the retreating snowline. Irrespective of their size, birds are thus able to store some resources necessary for egg laying at local or regional scales. It is thus important to make a distinction between local capital and distant capital breeding. The extent to which a bird is characterized as a distant capital, local capital, or an income breeder not only varies between species, but also between individuals and seasons.<br /

Emission Trading and the Role of Learning-By-Doing Spillovers in the Bottom-Up Energy-System ERIS Model

In this paper, using the "bottom-up" energy-system optimisation ERIS model, we examine the effects of emission trading on technology deployment, emphasising the role of technology learning spillovers. That is, the possibility that the learning accumulated in a particular technology in a given region may spill to other regions as well, leading to cost reductions there also. The effects of different configurations of interregional spillovers of learning in ERIS and the impact of the emission trading mechanism under those different circumstances are analysed. Including spatial spillovers of learning allows capturing the possibility that the imposition of greenhouse gas emission constraints in a given region may induce technological change in other regions, such as developing countries, even if the latter regions do not face emission constraints. Our stylised results point out the potential benefits of sound international cooperation between industrialised and developing regions on research, development, demonstration and deployment (RD3) of clean energy technologies and on the implementation of emission trading schemes