Density Perturbations in Chain Inflation

We consider the model of ``Chain Inflation,'' in which the period of inflation in our universe took the form of a long sequence of quantum tunneling events. We find that in the simplest such scenario, in which the tunneling processes are uniform, approximately 10^4 vacua per e-folding of inflation are required in order that the density perturbations produced are of an acceptable size. We arrive at this conclusion through a combination of analytic and numerical techniques, which could also serve as starting points for calculations with more general sets of assumptions.Comment: 28 pages, 16 figures; v2: corrected typos, increased resolution on D=2+1 data point

A Close and Supportive Interparental Bond During Pregnancy Predicts Greater Decline in Sexual Activity From Pregnancy to Postpartum: Applying an Evolutionary Perspective

A common topic for advice given to parents after childbirth – both from relationship experts and popular media – is how to “bounce back” to one’s pre-pregnancy sexuality, with warnings that postpartum declines in sexual frequency will take a serious toll on one’s relationship. However, these admonishments may not accurately reflect the ways in which the unique reproductive context of pregnancy and the postpartum transition alter associations between sexual frequency and relationship quality. Evolutionary perspectives on reproductive strategies would suggest that in the postpartum context, decreased sexual activity would help target parental investment in the current offspring (rather than creating new offspring); however, if the parental relationship is lacking in intimacy and support, continued sexual activity may help seal the cracks in the bond. We tested this theory in a longitudinal dyadic study of changes in relationship quality and sexual frequency from pregnancy to 6 months postpartum among 159 heterosexual couples. We found that across three different measures of relationship quality taken from interviews and behavioral observation of couple interactions, higher relationship quality (i.e., greater support, intimacy, and responsiveness) predicted greater decline in sexual frequency whereas sexual frequency remained relatively stable in lower quality relationships. These findings suggest that, during the postpartum transition, decreased sexual frequency may not be a reliable signal of poor relationship quality

Existential mental health implications for kin-caregivers of Alzheimer\u27s victims

The purpose of this paper is to briefly outline assessment and progression of Alzheimer\u27s disease (AD) in afflicted individuals (i.e., care recipients [CRs]) and review relevant research concerning the effects of AD progression on caregivers (CGs) as they care for loved ones. With this background, consideration will be made of how these findings suggest relevant tenets of Existential therapy. The author will also identify implications that could be meaningful to mental health professionals in their efforts to assist CGs as they attempt to cope with the emotional impact this disease has on them during caregiving and after the eventual death of the CR. The premise of this paper is that Existential Therapy (ET) is particularly well suited for this area of psychotherapy because of the salient issues involved and because ET concepts can be utilized within many psychotherapeutic approaches (Yalom, 1980)

Stratigraphy, Geochronology and Detrital Zircon Provenance of Two Silicic Ash Layers at Hagerman Fossil Beds National Monument, Idaho

Hagerman Fossil Beds National Monument (HAFO) is home to the world-famous Hagerman Horse Quarry. This site gives important insight into Pliocene age paleontology. Absolute ages of this site have been elusive, although researchers have assumed the site to be around 3.2 Ma. This study sought to determine more precise ages for the previously documented Hagerman Horse Quarry and Peters Gulch ash layers at HAFO thereby defining a more specific date for the Hagerman fossil assemblage, and to describe and interpret their sedimentary horizons. Detailed stratigraphic columns were created to describe sedimentary layers and establish marker beds. The sedimentology and stratigraphy are consistent with that of fluvial/flood plain depositional environments. Two ash samples were collected and analyzed using U/Pb zircon geochronology via laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Similar to previous studies, the majority of zircon crystals in these volcanic ashes are detrital in origin, ranging in age from 4 Ma to Precambrian. While the depositional age of these ash beds remains elusive, the detrital ages were grouped into three major volcanic events and described in order to identify the source of the detrital zircons and hosting sediment. These source areas include the Atlanta Lobe of the Idaho Batholith (80 – 100 Ma), the Challis Volcanic Group (45 – 52 Ma), and rhyolitic Yellowstone-Snake River Plain volcanics (4 – 17 Ma)

Characteristics of InAs/AlGaAs self-organized quantum dot modulation doped field effect transistors

We have investigated the dc characteristics of InGaAs/AlGaAs modulation doped field effect transistors in which a layer of self-organized InAs quantum dots is inserted adjacent to the pseudomorphic quantum well channel. Distinct steps and a negative differential resistance are observed in the current–voltage characteristics at room temperature and lower temperatures. These are attributed to conduction through the bound states in the quantum dots. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70192/2/APPLAB-72-26-3509-1.pd