A rare subclass of Type Ia supernovae (SNe Ia) shows evidence of strong interaction with a hydrogen-rich circumstellar medium (CSM); these objects are referred to as SNe Ia-CSM. PTF11kx began life as a SN Ia, but after a month it began to show indications of significant interaction with its CSM. This well-studied object solidified the connection between SNe Ia-CSM and more typical SNe Ia, despite their spectral similarity to Type IIn SNe (which likely come from massive star progenitors, as opposed to the white dwarf progenitors for the SNe Ia-CSM). The spectra of all ~20 known SNe Ia-CSM are dominated by Hα emission (with widths of ~2000 km s−1) and exhibit large Hα/Hβ intensity ratios; moreover, they have an almost complete lack of He I emission (see left panel of Figure 1). They also show possible evidence of dust formation through a decrease in the red wing of Hα 75–100 days past maximum brightness. The absolute magnitudes of SNe Ia-CSM are found to be -21.3 mag ≤ MR ≤ −19 mag (see right panel of Figure 1), and they also show ultraviolet emission at early times and strong infrared emission at late times (but no detected radio or X-ray emission). Finally, the host galaxies of SNe Ia-CSM imply that these objects come from a relatively young stellar population.

As a product of natural selection, pain behavior must serve an adaptive function for the species beyond the accurate portrayal of the pain experience. Pain behavior does not simply refer to the pain experience, but promotes survival of the species in various and complex ways. This means that there is no purely respondent or operant pain behavior found in nature.

Knowledge of the mechanical properties of interlevel dielectric films and their impact on sub-micron interconnect reliability is becoming more and more important as critical dimensions in ULSI circuits are scaled down. For example, lateral aluminum (Al) extrusions into spaces between metal lines, which become a more of a concern as the pitches shrink, appear to depend partially on properties of SiO2 underlayers. In this paper, the mechanical properties of several common interlevel dielectric SiO2 films such as undoped silica glass using a silane (SiH4) precursor, undoped silica glass using a tetraethylorthosilicate (TEOS) precursor, phosphosilicate glass (PSG) deposited by plasma-enhanced chemical vapor deposition (PECVD) and borophosphosilicate glass (BPSG) deposited by sub-atmosphere chemical vapor deposition (SACVD) were studied. Among the four common interlevel layers, BPSG exhibits the smallest modulus (E), hardness (H) and the highest the coefficients of thermal expansion (CTE). BPSG again has the lowest as-deposited compressive stress and the lowest local Si-O-Si strain before annealing. Stress interactions between the various SiO2 underlayers and the Al metal film are further investigated. The impact of dielectric elastic properties on interconnect reliability during thermal cycles is proposed.