2,048 research outputs found
Limits on extra dimensions in orbifold compactifications of superstrings
Perturbative breaking of supersymmetry in four-dimensional string theories
predict in general the existence of new large dimensions at the TeV scale. Such
dimensions can be consistent with perturbative unification up to the Planck
scale in a class of string models and open the exciting possibility of lowering
a part of the massive string spectrum at energies accessible to future
accelerators. The main signature is the production of Kaluza-Klein excitations
which have a very particular structure, strongly correlated with the
supersymmetry breaking mechanism. We present a model independent analysis of
the physics of these states in the context of orbifold compactifications of the
heterotic superstring. In particular, we compute the limits on the size of
large dimensions used to break supersymmetry.Comment: 16 pages, CPTH-A257.079
Strategies for the analysis of osteitic bone defects at the diaphysis of long bones
Septic diseases of the bone and the immediate surrounding soft tissue, i.e., osteitis, belong to the most alarming findings in recent traumatology and orthopedic surgery. The paramount goal of this therapy is to preserve the stable weight-bearing bones while maintaining a correct axis and proper working muscles and joints, in order to avoid permanent disability in the patient. “State-of-the-art” therapy of osteitis/osteomyelitis therapy has two priorities: eradication of the infection and reconstruction of bone and soft tissue. Surgical treatment of the affected bone segments and soft tissue, followed by reconstructive methods, continues to be the main basic therapy. It is often extremely difficult to decide whether the affected bone segment has to be resected, or whether bone continuity can be preserved. The following paper provides strategies and guidance to help guide decisions in this complex and challenging area
An SU(3) model for octet baryon and meson fragmentation
The production of the octet of baryons and mesons in e^+ e^- collisions is
analysed, based on considerations of SU(3) symmetry and a simple model for
SU(3) symmetry breaking in fragmentation functions. All fragmentation
functions, D_q^h(x, Q^2), describing the fragmentation of quarks into a member
of the baryon octet (and similarly for fragmentation into members of the meson
octet) are expressed in terms of three SU(3) symmetric functions, \alpha(x,
Q^2), \beta(x, Q^2), and \gamma(x, Q^2). With the introduction of an SU(3)
breaking parameter, \lambda, the model is successful in describing
hadroproduction data at the Z pole. The fragmentation functions are then
evolved using leading order evolution equations and good fits to currently
available data at 34 GeV and at 161 GeV are obtained.Comment: 24 pages LaTeX file including 11 postscript figure file
Large-Area Scintillator Hodoscope with 50 ps Timing Resolution Onboard BESS
We describe the design and performance of a large-area scintillator hodoscope
onboard the BESS rigidity spectrometer; an instrument with an acceptance of 0.3
m^{2}sr.
The hodoscope is configured such that 10 and 12 counters are respectively
situated in upper and lower layers.
Each counter is viewed from its ends by 2.5 inch fine-mesh photomultiplier
tubes placed in a stray magnetic field of 0.2 Tesla.
Various beam-test data are presented.
Use of cosmic-ray muons at ground-level confirmed 50 ps timing resolution for
each layer, giving an overall time-of-flight resolution of 70 ps rms using a
pure Gaussian resolution function.
Comparison with previous measurements on a similar scintillator hodoscope
indicates good agreement with the scaling law that timing resolution is
proportional to 1/, where is the effective
number of photoelectrons.Comment: 16 pages, 14 figure
Superposition effect and clan structure in forward-backward multiplicity correlations
The main purpose of this paper is to discuss the link between
forward-backward multiplicity correlations properties and the shape of the
corresponding final charged particle multiplicity distribution in various
classes of events in different collisions. It is shown that the same mechanism
which explains the shoulder effect and the H_n vs. n oscillations in charged
particle multiplicity distributions, i.e., the weighted superposition of
different classes of events with negative binomial properties, reproduces
within experimental errors also the forward-backward multiplicity correlation
strength in e+e- annihilation at LEP energy and allows interesting predictions
for pp collisions in the TeV energy region, to be tested at LHC, for instance
with the ALICE detector. We limit ourselves at present to study substructures
properties in hadron-hadron collisions and e+e- annihilation; they are examined
as ancillary examples in the conviction that their understanding might be
relevant also in other more complex cases.Comment: 16 page
Relationship Between Spirituality, Meaning in Life, Psychological Distress, Wish for Hastened Death, and Their Influence on Quality of Life in Palliative Care Patients.
Spiritual, existential, and psychological issues represent central components of quality of life (QOL) in palliative care. A better understanding of the dynamic nature underlying these components is essential for the development of interventions tailored to the palliative context.
The aims were to explore 1) the relationship between spirituality, meaning in life, wishes for hastened death and psychological distress in palliative patients and 2) the extent to which these nonphysical determinants influence QOL.
A cross-sectional study involving face-to-face interviews with Swiss palliative patients was performed, including the Schedule for Meaning in Life Evaluation (SMILE), the Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being Scale (FACIT-Sp), the Idler Index of Religiosity (IIR), the Hospital Anxiety and Depression Scale (HADS), and the Schedule of Attitudes toward Hastened Death (SAHD). QOL was measured with a single-item visual analogue scale (0-10).
Two hundred and six patients completed the protocol (51.5% female; mean age = 67.5 years). The results indicated a significant negative relationship between FACIT-Sp/SMILE and HADS total scores (P = 0.000). The best model for QOL explained 32.8% of the variance (P = 0.000) and included the FACIT-Sp, SMILE, and SAHD total scores, the IIR "private religiosity" score, as well as the HADS "depression" score.
Both spiritual well-being and meaning in life appear to be potential protective factors against psychological distress at the end of life. Since nonphysical determinants play a major role in shaping QOL at the end of life, there is a need for the development of meaning-oriented and spiritual care interventions tailored to the fragility of palliative patients
Economic growth in the post-socialist Russian Federation after 1991 : the role of institutions
The paper emphasizes the transition in Russia and the role institutions played before and during the process. In Russia, a ?big bang? approach was applied. That is to say, transition was conducted all of a sudden, omitting important underlying reforms. This practice should function as a shock therapy. Hence, the approach should leave no other chance than an abrupt adaption to the new free-market rules. These rules would then lead to fast economic growth and development, as they did in other places. However, since Russian GDP per capita and thereby living standards deteriorated dramatically in the years after the collapse of the Soviet Union, the plan did not work. At any rate, since then Russian economic indicators recovered and partly achieved their pre-1991 levels at the end of the last decade. The paper depicts Russia?s reform efforts and the subsequent developments. The close ties among the political elite, the banking sector and the old nomenklatura are demonstrated. The patrimonial system that persisted for centuries is still observable at the state level. At any rate, Russia can neither evade its historical and institutional development path nor its societal structures that are based on networks and nepotism. Russia?s systemic lack of the rule of law and therewith of secure property, the character of the Russian political system with the patriarch as the head of state and the resulting necessity of corruption and bribes inhibit the realization of its full growth potential
Superconformal constraints for QCD conformal anomalies
Anomalous superconformal Ward identities and commutator algebra in N = 1
super-Yang-Mills theory give rise to constraints between the QCD special
conformal anomalies of conformal composite operators. We evaluate the
superconformal anomalies that appear in the product of renormalized conformal
operators and the trace anomaly in the supersymmetric spinor current and check
the constraints at one-loop order. In this way we prove the universality of QCD
conformal anomalies, which define the non-diagonal part of the anomalous
dimension matrix responsible for scaling violations of exclusive QCD amplitudes
at the next-to-leading order.Comment: 30 pages, 2 figures, LaTe
Quark Mass Corrections to the Perturbative Thrust and its Effect on the determination of
We consider the effects of quark masses to the perturbative thrust in
annihilation. In particular we show that perturbative power
corrections resulting from non-zero quark masses considerably alters the size
of the non-perturbative power corrections and consequently, significantly
changes the fitted value of .Comment: Latex, 6 pages, 2 figures, minor change in text, added one referenc
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