92 research outputs found

    Observing the First Stars and Black Holes

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    The high sensitivity of JWST will open a new window on the end of the cosmological dark ages. Small stellar clusters, with a stellar mass of several 10^6 M_sun, and low-mass black holes (BHs), with a mass of several 10^5 M_sun should be directly detectable out to redshift z=10, and individual supernovae (SNe) and gamma ray burst (GRB) afterglows are bright enough to be visible beyond this redshift. Dense primordial gas, in the process of collapsing from large scales to form protogalaxies, may also be possible to image through diffuse recombination line emission, possibly even before stars or BHs are formed. In this article, I discuss the key physical processes that are expected to have determined the sizes of the first star-clusters and black holes, and the prospect of studying these objects by direct detections with JWST and with other instruments. The direct light emitted by the very first stellar clusters and intermediate-mass black holes at z>10 will likely fall below JWST's detection threshold. However, JWST could reveal a decline at the faint-end of the high-redshift luminosity function, and thereby shed light on radiative and other feedback effects that operate at these early epochs. JWST will also have the sensitivity to detect individual SNe from beyond z=10. In a dedicated survey lasting for several weeks, thousands of SNe could be detected at z>6, with a redshift distribution extending to the formation of the very first stars at z>15. Using these SNe as tracers may be the only method to map out the earliest stages of the cosmic star-formation history. Finally, we point out that studying the earliest objects at high redshift will also offer a new window on the primordial power spectrum, on 100 times smaller scales than probed by current large-scale structure data.Comment: Invited contribution to "Astrophysics in the Next Decade: JWST and Concurrent Facilities", Astrophysics & Space Science Library, Eds. H. Thronson, A. Tielens, M. Stiavelli, Springer: Dordrecht (2008

    An Application of the Concept of the Therapeutic Alliance To Sadomasochistic Pathology

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    This paper traces the history of the therapeutic alliance concept, examining how it has been used and misused, at times elevated to a central position and at others rejected altogether. The loss of this concept created a vacuum in classical psychoanalysis that has been filled by rival theories. The continuing usefulness of looking at the treatment process through the lens of the therapeutic alliance, particularly in relation to the manifold difficulties of working with sadomasochistic pathology, is suggested. To this end, revisions of the theory of the therapeutic alliance are suggested to address some of the difficulties that have arisen in conceptualizing this aspect of the therapeutic relationship, and to provide an integrated dynamic model for working with patients at each phase of treatment. This revised model acknowledges the complexity of the domain and encompasses the multiple tasks, functions, partners, and treatment phases involved. The utility of the revised theory is illustrated in application to understanding the sadomasochistic, omnipotent resistances of a female patient through the phases of her analysis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66889/2/10.1177_00030651980460031301.pd

    Physical Processes in Star Formation

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    © 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00693-8.Star formation is a complex multi-scale phenomenon that is of significant importance for astrophysics in general. Stars and star formation are key pillars in observational astronomy from local star forming regions in the Milky Way up to high-redshift galaxies. From a theoretical perspective, star formation and feedback processes (radiation, winds, and supernovae) play a pivotal role in advancing our understanding of the physical processes at work, both individually and of their interactions. In this review we will give an overview of the main processes that are important for the understanding of star formation. We start with an observationally motivated view on star formation from a global perspective and outline the general paradigm of the life-cycle of molecular clouds, in which star formation is the key process to close the cycle. After that we focus on the thermal and chemical aspects in star forming regions, discuss turbulence and magnetic fields as well as gravitational forces. Finally, we review the most important stellar feedback mechanisms.Peer reviewedFinal Accepted Versio

    Is There Such a Thing as Christian Sex?

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    It is challenging for Christian pastors and counselors to discuss human sexuality in ways which do not alienate liberals on the left, conservatives on the right, or biologists in the middle. Feminists frequently see males as dominating or insensitive, and conservative Christians sometimes feed into this by emphasizing patriarchal models of marriage as if this were the biblical paradigm for all time. Evolutionary biologists view sexuality primarily as a means of propagating the species. Into this cacophony of strident voices the Christian seeks to inject a calm but clear message: Christian sexuality is primarily a search for intimacy. In a culture obsessed with sexuality as entertainment, the followers of Christ call others to view human sexuality not primarily in terms of eroticism, power, or procreation, but rather in terms of psychological intimacy. From a biblical perspective, becoming one flesh, with one\u27s mate also provides the occasion for becoming a co-creator with the eternal I AM. In addition to the procreational potential and orgasmic excitement provided by sexual intercourse, God intended for these encounters to be loaded with an abundance of psychological intimacy. Intimacy is the raison d\u27etre of sexual relationships. Intimacy provides sexuality with a quality that can mollify crises in the present life, and imbue sexuality with a splendor worthy of the next life as well. © 2002 Human Sciences Press, Inc

    Associations between maternal psychological distress and salivary cortisol during pregnancy : A mixed-models approach

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    Background: Maternal psychological distress during pregnancy is related to adverse child behavioral and emotional outcomes later in life, such as ADHD and anxiety/depression. The underlying mechanisms for this, however, are still largely unknown. The hypothalamic-pituitary-adrenal (HPA)-axis, with its most important effector hormone cortisol, has been proposed as a mechanism, but results have been inconsistent. The current study investigated the association between maternal psychological distress (i.e. anxiety and depressive symptoms) and maternal cortisol levels during pregnancy using a mixed models approach. Method: During three pregnancy trimesters, mothers (N = 170) collected four salivary samples for two consecutive days. Mothers reported symptoms of anxiety and depression three times during pregnancy (at 13.3 ± 1.1, 20.2 ± 1.5, and 33.8 ± 1.5 weeks of pregnancy, respectively) using the anxiety subscale of the Symptom Checklist (SCL-90), the Spielberger State and Trait Anxiety Inventory (STAI), and the Edinburgh Postnatal Depression Scale (EPDS). Specific fears and worries during pregnancy were measured with the short version of the Pregnancy Related Anxiety Questionnaire (PRAQ-R). Results: We found a significant effect of SCL-90 anxiety subscale on cortisol levels at awakening (p =.008), indicating that mothers with higher anxiety showed lower cortisol at awakening. Maternal psychological variables explained 10.5% of the variance at the person level in awakening cortisol level, but none in the overall diurnal cortisol model. Conclusion: More research is necessary to unravel the underlying mechanisms of the association between maternal psychological distress and cortisol and the search for mechanisms other than the HPA-axis should be continued and extended

    Importance of broadband noise for advanced turboprops

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