Geochelone carbonaria

Number of Pages: 7Integrative BiologyGeological Science

Microscopic approach to pion-nucleus dynamics

Elastic scattering of pions from finite nuclei is investigated utilizing a contemporary, momentum--space first--order optical potential combined with microscopic estimates of second--order corrections. The calculation of the first--order potential includes:\ \ (1)~full Fermi--averaging integration including both the delta propagation and the intrinsic nonlocalities in the $\pi$-$N$ amplitude, (2)~fully covariant kinematics, (3)~use of invariant amplitudes which do not contain kinematic singularities, and (4)~a finite--range off--shell pion--nucleon model which contains the nucleon pole term. The effect of the delta--nucleus interaction is included via the mean spectral--energy approximation. It is demonstrated that this produces a convergent perturbation theory in which the Pauli corrections (here treated as a second--order term) cancel remarkably against the pion true absorption terms. Parameter--free results, including the delta--nucleus shell--model potential, Pauli corrections, pion true absorption, and short--range correlations are presented. (2 figures available from authors)Comment: 13 page

The Computational Complexity of the Lorentz Lattice Gas

The Lorentz lattice gas is studied from the perspective of computational complexity theory. It is shown that using massive parallelism, particle trajectories can be simulated in a time that scales logarithmically in the length of the trajectory. This result characterizes the ``logical depth" of the Lorentz lattice gas and allows us to compare it to other models in statistical physics.Comment: 9 pages, LaTeX, to appear in J. Stat. Phy

Successful management buyouts: Are they really more entrepreneurial?

The paper explores the impact of entrepreneurial management dimensions on post-MBO financial performance. We use Stevenson’s conceptualization of entrepreneurship (1983), empirically validated by Brown, Davidsson and Wiklund (2001), positing that entrepreneurial companies will be involved in recognizing and exploiting opportunity, regardless of the resources controlled. From the literature we hypothesize positive effects of entrepreneurial management dimensions on post-MBO financial performance. We find that successful buyout managers cannot be classified as entrepreneurs on all entrepreneurial dimensions. Instead they ambidextrously combine the pursuit of valuable opportunities with the exploitation and control of their resources. Implications for theory and managerial practice are discussed

Systematic reviews of complementary therapies - an annotated bibliography. Part 1: Acupuncture

Background Complementary therapies are widespread but controversial. We aim to provide a comprehensive collection and a summary of systematic reviews of clinical trials in three major complementary therapies (acupuncture, herbal medicine, homeopathy). This article is dealing with acupuncture. Potentially relevant reviews were searched through the register of the Cochrane Complementary Medicine Field, the Cochrane Library, Medline, and bibliographies of articles and books. To be included articles had to review prospective clinical trials of acupuncture; had to describe review methods explicitly; had to be published; and had to focus on treatment effects. Information on conditions, interventions, methods, results and conclusions was extracted using a pretested form and summarized descriptively. Results From a total of 48 potentially relevant reviews preselected in a screeening process 39 met the inclusion criteria. 22 were on various pain syndromes or rheumatic diseases. Other topics addressed by more than one review were addiction, nausea, asthma and tinnitus. Almost unanimously the reviews state that acupuncture trials include too few patients. Often included trials are heterogeneous regarding patients, interventions and outcome measures, are considered to have insufficient quality and contradictory results. Convincing evidence is available only for postoperative nausea, for which acupuncture appears to be of benefit, and smoking cessation, where acupuncture is no more effective than sham acupuncture. Conclusions A large number of systematic reviews on acupuncture exists. What is most obvious from these reviews is the need for (the funding of) well-designed, larger clinical trials

Granular gases under extreme driving

We study inelastic gases in two dimensions using event-driven molecular dynamics simulations. Our focus is the nature of the stationary state attained by rare injection of large amounts of energy to balance the dissipation due to collisions. We find that under such extreme driving, with the injection rate much smaller than the collision rate, the velocity distribution has a power-law high energy tail. The numerically measured exponent characterizing this tail is in excellent agreement with predictions of kinetic theory over a wide range of system parameters. We conclude that driving by rare but powerful energy injection leads to a well-mixed gas and constitutes an alternative mechanism for agitating granular matter. In this distinct nonequilibrium steady-state, energy cascades from large to small scales. Our simulations also show that when the injection rate is comparable with the collision rate, the velocity distribution has a stretched exponential tail.Comment: 6 pages, 7 figures; new version contains 2 new figures and text describing cascade

Women's quality of life is decreased by acute cystitis and antibiotic adverse effects associated with treatment

BACKGROUND: Although acute cystitis is a common infection in women, the impact of this infection and its treatment on women's quality of life (QOL) has not been previously described. Objectives: To evaluate QOL in women treated for acute cystitis, and describe the relationship between QOL, clinical outcome and adverse events of each of the interventions used in the study. METHODS: Design. Randomized, open-label, multicenter, treatment study. Setting. Two family medicine outpatient clinics in Iowa. Patients. One-hundred-fifty-seven women with clinical signs and symptoms of acute uncomplicated cystitis. Intervention. Fifty-two patients received trimethoprim/sulfamethoxazole 1 double-strength tablet twice daily for 3 days, 54 patients received ciprofloxacin 250 mg twice daily for 3 days and 51 patients received nitrofurantoin 100 mg twice daily for 7 days. Measurements. QOL was assessed at the time of enrollment and at 3, 7, 14 and 28 days after the initial visit. QOL was measured using a modified Quality of Well-Being scale, a validated, multi-attribute health scale. Clinical outcome was assessed by telephone interview on days 3, 7, 14 and 28 using a standardized questionnaire to assess resolution of symptoms, compliance with the prescribed regimen, and occurrence of adverse events. RESULTS: Patients experiencing a clinical cure had significantly better QOL at days 3 (p = 0.03), 7 (p < 0.001), and 14 (p = 0.02) compared to patients who failed treatment. While there was no difference in QOL by treatment assignment, patients experiencing an adverse event had lower QOL throughout the study period. Patients treated with ciprofloxacin appeared to experience adverse events at a higher rate (62%) compared to those treated with TMP/SMX (45%) and nitrofurantoin (49%), however the difference was not statistically significant (p = 0.2). CONCLUSION: Patients experiencing cystitis have an increase in their QOL with treatment. Those experiencing clinical cure have greater improvement in QOL compared to patients fail therapy. While QOL is improved by treatment, those reporting adverse events have lower overall QOL compared to those who do not experience adverse events. This study is important in that it suggests that both cystitis and antibiotic treatment can affect QOL in a measurable way