Infrared astronomy

Spacecraft and astronomical observations of infrare

Modelling Epsilon Aurigae without solid particles

Three components can be expected to contribute to the emission of epsilon Aurigae. There is a primary F star. There is an opaque disk which occults it, and there is a gas stream which is observed to produce absorption lines. Evidence that the disk is not responsible for the gas stream lines comes both from the radial velocities, which are too small, and from the IR energy distribution out of eclipse, which shows free-free emission that would produce inadequate optical depth in electron scattering. The color temperature of the IR excess can give misleading indications of low temperature material. Free-free emission at 10,000 K between 10 and 20 microns has a color temperature of 350 K. Attempts to mold the system are discussed

Classical and fluctuation-induced electromagnetic interactions in micronscale systems: designer bonding, antibonding, and Casimir forces

Whether intentionally introduced to exert control over particles and macroscopic objects, such as for trapping or cooling, or whether arising from the quantum and thermal fluctuations of charges in otherwise neutral bodies, leading to unwanted stiction between nearby mechanical parts, electromagnetic interactions play a fundamental role in many naturally occurring processes and technologies. In this review, we survey recent progress in the understanding and experimental observation of optomechanical and quantum-fluctuation forces. Although both of these effects arise from exchange of electromagnetic momentum, their dramatically different origins, involving either real or virtual photons, lead to different physical manifestations and design principles. Specifically, we describe recent predictions and measurements of attractive and repulsive optomechanical forces, based on the bonding and antibonding interactions of evanescent waves, as well as predictions of modified and even repulsive Casimir forces between nanostructured bodies. Finally, we discuss the potential impact and interplay of these forces in emerging experimental regimes of micromechanical devices.Comment: Review to appear on the topical issue "Quantum and Hybrid Mechanical Systems" in Annalen der Physi

Comparative Spectra of Oxygen-Rich vs. Carbon-Rich Circumstellar Shells: VY Canis Majoris and IRC+10216 at 215-285 GHz

A sensitive (1{\sigma} rms at 1 MHz resolution ~3 mK) 1 mm spectral line survey (214.5-285.5 GHz) of VY Canis Majoris (VY CMa) and IRC+10216 has been conducted to compare the chemistries of oxygen and carbon-rich circumstellar envelopes. This study was carried out using the Submillimeter Telescope (SMT) of the Arizona Radio Observatory (ARO) with a new ALMA-type receiver. This survey is the first to chemically characterize an O-rich circumstellar shell at millimeter wavelengths. In VY CMa, 128 emission features were detected arising from 18 different molecules, and in IRC+10216, 720 lines were observed, assigned to 32 different species. The 1 mm spectrum of VY CMa is dominated by SO2 and SiS; in IRC +10216, C4H and SiC2 are the most recurrent species. Ten molecules were common to both sources: CO, SiS, SiO, CS, CN, HCN, HNC, NaCl, PN, and HCO+. Sulfur plays an important role in VY CMa, but saturated/unsaturated carbon dominates the molecular content of IRC+10216, producing CH2NH, for example. Although the molecular complexity of IRC+10216 is greater, VY CMa supports a unique "inorganic" chemistry leading to the oxides PO, AlO, and AlOH. Only diatomic and triatomic compounds were observed in VY CMa, while species with 4 or more atoms are common in IRC+10216, reflecting carbon's ability to form strong multiple bonds, unlike oxygen. In VY CMa, a new water maser (v_2=2) has been found, as well as vibrationally-excited NaCl. Toward IRC+10216, vibrationally-excited CCH was detected for the first time.Comment: 21 pages, 3 figures, accepted for publication in Astrophysical Journal Letter

Targeting tumor multicellular aggregation through IGPR-1 inhibits colon cancer growth and improves chemotherapy

Adhesion to extracellular matrix (ECM) is crucially important for survival of normal epithelial cells as detachment from ECM triggers specific apoptosis known as anoikis. As tumor cells lose the requirement for anchorage to ECM, they rely on cell-cell adhesion 'multicellular aggregation' for survival. Multicellular aggregation of tumor cells also significantly determines the sensitivity of tumor cells to the cytotoxic effects of chemotherapeutics. In this report, we demonstrate that expression of immunoglobulin containing and proline-rich receptor-1 (IGPR-1) is upregulated in human primary colon cancer. Our study demonstrates that IGPR-1 promotes tumor multicellular aggregation, and interfering with its adhesive function inhibits multicellular aggregation and, increases cell death. IGPR-1 supports colon carcinoma tumor xenograft growth in mouse, and inhibiting its activity by shRNA or blocking antibody inhibits tumor growth. More importantly, IGPR-1 regulates sensitivity of tumor cells to the chemotherapeutic agent, doxorubicin/adriamycin by a mechanism that involves doxorubicin-induced AKT activation and phosphorylation of IGPR-1 at Ser220. Our findings offer novel insight into IGPR-1's role in colorectal tumor growth, tumor chemosensitivity, and as a possible novel anti-cancer target.Grant support from: R01 CA175382/CA/NCI NIH HHS/United States, R21 CA191970/CA/NCI NIH HHS/United States, and R21 CA193958/CA/NCI NIH HHS/United State

The Hot R Coronae Borealis Star DY Centauri is a Binary

The remarkable hot R Coronae Borealis (RCB) star DY Cen is revealed to be the first and only binary system to be found among the RCB stars and their likely relatives, including the extreme helium stars and the hydrogen-deficient carbon stars. Radial velocity determinations from 1982 to 2010 have shown that DY Cen is a single-lined spectroscopic binary in an eccentric orbit with a period of 39.67 days. It is also one of the hottest and most H-rich member of the class of RCB stars. The system may have evolved from a common envelope to its current form.Spanish Ministry of Economy and Competitiveness AYA-2011-27754McDonald Observator

Different Ways of Reading, or Just Making the Right Noises?

What does reading look like? Can learning to read be reduced to the acquisition of a set of isolable skills, or proficiency in reading be equated with the independence of the solitary, silent reader of prose fiction? These conceptions of reading and reading development, which figure strongly in educational policy, may appear to be simple common sense. But both ethnographic data and evidence from literary texts suggest that such paradigms offer, at most, a partial and ahistorical picture of reading. An important dimension, neglected in the dominant paradigms, is the irreducibly social quality of reading practices

Receiving Aphasia Intervention in a Virtual Environment: The Participants’ Perspective

Background: Digital technology is making an increasing contribution to aphasia therapy. However applications of virtual reality are rare. EVA Park is a virtual island developed with and for people with aphasia. It is a multi-user environment, which enables people with aphasia to interact with support workers, therapists and each other. The first study to use EVA Park in aphasia rehabilitation demonstrated significant gains in functional communication. This paper augments the findings of that study, by reporting results from qualitative interviews conducted with the 20 study participants. Aims: This study aimed to determine the views of participants about the intervention that they received in EVA Park, and the impacts of that intervention. Long-term retrospective views were also explored. Methods & Procedures: Participants took part in 1:1, semi-structured interviews two weeks before (Entry) and to weeks after (Exit) the intervention. Questions focussed on activities undertaken by participants, communication, changes since the stroke and uses of technology. Exit interviews additionally explored participants’ views and experiences of EVA Park and any perceived impacts of the intervention. A sub-set of 5 participants was interviewed at least one year later, to explore long term recollections of the EVA Park intervention and any perceived long term impacts. Interview data were transcribed and subject to framework analysis. Outcomes & Results: The thematic framework comprised 10 parent themes and 33 sub-themes. Following ‘affect’, the largest single theme related to EVA Park, with 636 coded references. Comments were overwhelmingly positive. EVA Park intervention was strongly associated with fun and enjoyment. Participants particularly valued their relationship with the support workers who delivered the intervention. The virtual locations and activities in EVA Park were also appreciated, together with the contact with other participants. Perceived impacts related to communication, activity, computer use and confidence. Most participants in the long term interviews described maintained impacts. Conclusions: These interview results indicate that the first intervention delivered in EVA Park was highly acceptable to participants and perceived as beneficial. They augment the findings of our experimental study and suggest that EVA Park could be a valuable addition to the resources available to practising clinician