29,744 research outputs found
Light front field theory of relativistic quark matter
Light-front quantization to many-particle systems of finite temperature and
density provides a novel approach towards a relativistic description of quark
matter and allows us to calculate the perturbative as well as the
non-perturbative regime of QCD. Utilizing a Dyson expansion of light-front
many-body Green functions we have so far calculated three-quark, quark-quark,
and quark-antiquark correlations that lead to the chiral phase transition, the
formation of hadrons and color superconductivity in a hot and/or dense
environment. Presently, we use an effective zero-range interaction, to compare
our results with the more traditional instant form approach where applicable.Comment: contribution to Quark Matter 2005, 18th International Conference on
Nucleus Nucleus Colisions, 4 pages, 2 figures, hiph-preprint.sty file neede
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The Scientist-Practitioner in a Counselling Psychology Setting
The human psyche is influenced by an extraordinary complexity of experiences. Many would therefore maintain that we can never completely understand another human being. As scientist-practitioners, is our purported allegiance to, and reliance upon, ‘official’ sources of knowledge (including theory and scientific evidence) sufficient for us to be confident that we can construct consistently helpful solutions from the myriad clinical data at our fingertips? Should we as psychologists accept that full understanding of causality is simply not an achievable objective? If we adopt the position that we can never fully explain causes, however, what role do we actually play? Can our interventions even be considered valid, let alone scientific?
The question of how practitioners reflect upon their activity, and of the scientific assumptions behind their work, has occupied much debate in the field of psychology, and the many different strands of this debate are woven throughout the fabric of this book. In this chapter, we consider some of the many implications of this debate for counselling psychologists.
Specifically, we begin by exploring the position of counselling psychology within the profession more broadly, and consider its place in the current controversy about the scientist-practitioner role. Next, we articulate some of our own practice in this regard, attempting not only to make note of the systematic approaches that we employ in counselling psychology but also to incorporate the wide range of expectation and experience that comes to the therapeutic endeavour. Finally, we try to define the type of scientist-practitioner that we envision in a counselling psychology setting
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Termination of psychotherapy: The journey of ten psychoanalytic and psychodynamic therapists
Objectives: Literature on termination originates mainly from clinical and theoretical accounts as well as practitioners' autobiographical reports. There is, however, a paucity of psychological research on termination, and studies of therapists' experiences are particularly rare. The purpose of this study is to examine the process of termination of therapy based on therapists' narratives of experiences of endings with patients. Design: Grounded Theory methodology has been applied in this study in order to conceptualise the process of termination from the therapist’s perspective. Methods: Ten psychoanalytic and psychodynamic therapists were interviewed for this study. Results: Grounded Theory analysis of the data revealed five central categories: therapist as a person, therapist's awareness of termination, development of therapeutic relationship, working through termination, and the aftermath (post-termination phase). Conclusions: The results offer a Grounded Theory model of the therapist's journey through termination of therapy with patients. Subcategories and their relationships will be explored. Implications for clinical practice, limitations and suggestions for further research will be discussed
Sindbis virus ts103 has a mutation in glycoprotein E2 that leads to defective assembly of virions
Sindbis virus mutant ts103 is aberrant in the assembly of virus particles. During virus budding, proper nucleocapsid-glycoprotein interactions fail to occur such that particles containing many nucleocapsids are formed, and the final yield of virus is low. We have determined that a mutation in the external domain of glycoprotein E2, Ala-344-->Val, is the change that leads to this phenotype. Mapping was done by making recombinant viruses between ts103 and a parental strain of the virus, using a full-length cDNA clone of Sindbis virus from which infectious RNA can be transcribed, together with sequence analysis of the region of the genome shown in this way to contain the ts103 lesion. A partial revertant of ts103, called ts103R, was also mapped and sequenced and found to be a second-site revertant in which a change in glycoprotein E1 from lysine to methionine at position 227 partially suppresses the phenotypic effects of the change at E2 position 344. An analysis of revertants from ts103 mutants in which the Ala-->Val change had been transferred into a defined background showed that pseudorevertants were more likely to arise than were true revertants and that the ts103 change itself reverted very infrequently. The assembly defect in ts103 appeared to result from weakened interactions between the virus membrane glycoproteins or between these glycoproteins and the nucleocapsid during budding. Both the E2 mutation leading to the defect in virus assembly and the suppressor mutation in glycoprotein E1 are in the domains external to the lipid bilayer and thus in domains that cannot interact directly with the nucleocapsid. This suggests that in ts103, either the E1-E2 heterodimers or the trimeric spikes (consisting of three E1-E2 heterodimers) are unstable or have an aberrant configuration, and thus do not interact properly with the nucleocapsid, or cannot assembly correctly to form the proper icosahedral array on the surface of the virus
Bone loss and human adaptation to lunar gravity
Long-duration space missions and establishment of permanently manned bases on the Moon and Mars are currently being planned. The weightless environment of space and the low-gravity environments of the Moon and Mars pose an unknown challenge to human habitability and survivability. Of particular concern in the medical research community today is the effect of less than Earth gravity on the human skeleton, since the limits, if any, of human endurance in low-gravity environments are unknown. This paper provides theoretical predictions on bone loss and skeletal adaptation to lunar and other nonterrestrial-gravity environments based upon the experimentally derived relationship, density approximately (mass x gravity)(exp 1/8). The predictions are compared to skeletal changes reported during bed rest, immobilization, certrifugation, and spaceflight. Countermeasures to reduce bone losses in fractional gravity are also discussed
Shellflow. I. The Convergence of the Velocity Field at 6000 km/s
We present the first results from the Shellflow program, an all-sky
Tully-Fisher (TF) peculiar velocity survey of 276 Sb-Sc galaxies with redshifts
between 4500 and 7000 km/s. Shellflow was designed to minimize systematic
errors between observing runs and between telescopes, thereby removing the
possibility of a spurious bulk flow caused by data inhomogeneity. A fit to the
data yields a bulk flow amplitude V_bulk = 70{+100}{-70} km/s (1 sigma error)
with respect to the Cosmic Microwave Background, i.e., consistent with being at
rest. At the 95% confidence level, the flow amplitude is < 300 km/s. Our
results are insensitive to which Galactic extinction maps we use, and to the
parameterization of the TF relation. The larger bulk motion found in analyses
of the Mark III peculiar velocity catalog are thus likely to be due to
non-uniformities between the subsamples making up Mark III. The absence of bulk
flow is consistent with the study of Giovanelli and collaborators and flow
field predictions from the observed distribution of IRAS galaxies.Comment: Accepted version for publication in ApJ. Includes an epitaph for
Jeffrey Alan Willick (Oct 8, 1959 - Jun 18, 2000
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