A Large Atom Number Metastable Helium Bose-Einstein Condensate

We have produced a Bose-Einstein condensate of metastable helium (4He*) containing over 1.5x10^7 atoms, which is a factor of 25 higher than previously achieved. The improved starting conditions for evaporative cooling are obtained by applying one-dimensional Doppler cooling inside a magnetic trap. The same technique is successfully used to cool the spin-polarized fermionic isotope (3He*), for which thermalizing collisions are highly suppressed. Our detection techniques include absorption imaging, time-of-flight measurements on a microchannel plate detector and ion counting to monitor the formation and decay of the condensate.Comment: 4 pages, 3 figures (changed content

Quantum dynamics of the Li+HF-->H+LiF reaction at ultralow temperatures

Quantum mechanical calculations are reported for the Li+HF(v=0,1,j=0)-->H+LiF(v',j') bimolecular scattering process at low and ultralow temperatures. Calculations have been performed for zero total angular momentum using a recent high accuracy potential energy surface for the X 2A' electronic ground state. For Li+HF(v=0,j=0), the reaction is dominated by resonances due to the decay of metastable states of the Li...F-H van der Waals complex. Assignment of these resonances has been carried out by calculating the eigenenergies of the quasibound states. We also find that while chemical reactivity is greatly enhanced by vibrational excitation the resonances get mostly washed out in the reaction of vibrationally excited HF with Li atoms. In addition, we find that at low energies, the reaction is significantly suppressed due to the formation of rather deeply bound van der Waals complexes and the less efficient tunneling of the relatively heavy fluorine atom.Comment: 24 pages, 8 figures, 1 table, submitted to J. Chem. Phy

Quality of life (QoL) as predictive mediator variable for survival in patients with intracerebral neoplasma during radiotherapy

Background: The prognosis for patients with malignant astrocytoma or brain metastases is often fatal despite intensive therapy. Therefore we wished to elucidate whether the quality of life (QoL) is a determinant of overall survival (OAS). Patients and Methods: From 1997 to 2000 153 patients with brain tumours were screened; 39 patients (26%) refused to participate and further 47 patients were excluded (cerebral impairment 14%, amaurosis/language problems 3%, Karnofsky performance score < 50% 7%, death 8%, non-compliance 7%). Thus, 57 patients were analysed (33 with primary brain tumours, 24 with brain metastases). With the FACT-G questionnaire cancer-specific aspects of health-related QoL were assessed. Results: Patients with metastases showed a lower QoL in the physical sphere than patients with astrocytoma, but there were no significant differences in OAS. Median survival of patients with good QoL was 31.3 months versus 14.2 months in patients with bad QoL. Only the two variables `living with a spouse' and FACT-G sum score had a statistically significant influence on survival (p = 0.033 and p = 0.003) modelled by the Cox-PH regression. Patients who did not live with a spouse had shorter survival times than the other patients. Conclusion: Health-related QoL can serve to identify a patient group with higher risks of death

Cost-effectiveness of cognitive-behavioral group therapy for dysfunctional fear of progression in cancer patients

Anxiety and fear are often associated with chronic conditions such as cancer. This paper targets the cost-effectiveness analysis of a cognitive-behavioral group therapy (CBT) in comparison to a client-centered, supportive-experiential group therapy (SET) in cancer patients with dysfunctional fear of progression. An incremental cost-effectiveness analysis was performed using data from a randomized controlled trial among cancer patients receiving inpatient rehabilitation. The means, 95% confidence intervals [95% CI], incremental cost-effectiveness graphic and acceptability curve were obtained from 1,000 bootstrap replications. A total of 174 patients were included in the economic evaluation. The estimated means [95% CI] of direct costs and reduction of fear of progression were €9,045.03 [6,359.07; 12,091.87] and 1.41 [0.93; 1.92] for patients in the SET and €6,682.78 [4,998.09; 8,440.95] and 1.44 [1.02; 1.09] for patients in the CBT. The incremental cost-effectiveness ratio [95% CI] amounts to minus €78,741.66 [−154,987.20; 110,486.32] for an additional unit of effect. Given the acceptability curve, there is a 92.4% chance that the CBT, compared with the SET, is cost-effective without the need of additional costs to payers. Our main result is the superior cost-effectiveness of the cognitive-behavioral intervention program in comparison to the non-directive encounter group for our sample of cancer patients with high levels of anxiet

Collisional Properties of Cold Spin-Polarized Metastable Neon Atoms

We measure the rates of elastic and inelastic two-body collisions of cold spin-polarized neon atoms in the metastable 3P2 state for 20^Ne and 22^Ne in a magnetic trap. From particle loss, we determine the loss parameter of inelastic collisions beta=6.5(18)x10^{-12} cm^3s^{-1} for 20^Ne and beta=1.2(3)x10^{-11}cm^3{s}^{-1} for 22^Ne. These losses are caused by ionizing (i.e. Penning) collisions %to more than and occur less frequently than for unpolarized atoms. This proves the suppression of Penning ionization due to spin-polarization. From cross-dimensional relaxation measurements, we obtain elastic scattering lengths of a=-180(40) a_0 for 20^Ne and a=+150(+80/-50) a_0 for 22^Ne, where a_0=0.0529 nm.Comment: 4 pages, 3 figure

Coping of cancer patients during and after radiotherapy - a follow-up of 2 years

Aim: We wanted to understand coping strategies specific to different phases up to two years after radiotherapy, to identify patients who are at higher risk of mood disturbances and to characterise the association between coping strategies and psychosocial adaptation. Patients and Methods: From 1997 to 2001, 2,169 patients with different diagnoses were screened (27.8% refused to participate). Data of 276 patients from the beginning of radiotherapy (ti1) and 5 follow-up investigations (ti6/2 years) could be analysed. With the FKV ( Freiburg Questionnaire Coping with Disease) cancer-specific coping aspects were assessed. The association between coping styles and psychosocial adaptation was evaluated using the Questionnaire on Stress in Cancer Patients (QSC) and the questionnaire on Functional Assessment of Cancer Treatment (FACT-G). Results: `Active problem-orientated' coping and `distractions' are the most important coping strategies. Only `active problem-orientated' and `depressive' coping showed a significant decrease. We observed higher means on the scales of the FKV in women. Marital status ( single, married, divorced/widowed) had a significant influence on active problem-orientated coping and spirituality. Age, children, education, T/M status and curative/ palliative intention of treatment had no influence on coping styles. Breast cancer patients and lymphoma patients demonstrated the highest use of coping strategies after radiotherapy with a significant decrease of `active problem-orientated coping'. Depressive coping and minimizing importance at ti1 were associated with high psychosocial distress and low quality of life (QoL) at ti6. Conclusion: The correlation of coping mechanisms at the beginning of radiotherapy with low QoL and high psychosocial stress at 2 years could help to identify patients at risk for low psychosocial adaptation. Psychooncologically trained teams of physicians would best correspond to this profile of needs and would contribute significantly to an ameliorated adaptation of patients to cancer which could lead to higher life satisfaction

Two and three electrons in a quantum dot: 1/|J| - expansion

We consider systems of two and three electrons in a two-dimensional parabolic quantum dot. A magnetic field is applied perpendicularly to the electron plane of motion. We show that the energy levels corresponding to states with high angular momentum, J, and a low number of vibrational quanta may be systematically computed as power series in 1/|J|. These states are relevant in the high-B limit.Comment: LaTeX, 15 pages,6 postscript figure

Chemical Accelerator Studies of Isotope Effects on Collision Dynamics of Ion–Molecule Reactions: Elaboration of a Model for Direct Reactions

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/53/2/10.1063/1.1674042.Crossed‐beam studies on isotopic variants of the reaction Ar+ + H2→ArH+ are reported. Both velocity and angular distributions of the ionic product as a function of initial translational energy, down to 0.1 eV (center of mass), have been measured. At lowest energies there is a gain in the translational energy of the products over that of the reactants, but at higher energies there is increasing conversion of kinetic into internal energy. While this represents the most probable course of the reaction there is a fairly wide distribution about the median values. Results confirm that this reaction is predominantly direct at all energies and provide no evidence for intermediate persistent complex formation. They are also consistent with a model for direct reactions previously proposed. The data on reaction with HD permit further development of this mechanism. The reactants are mutually accelerated by their long‐range attractive potential until hydrogen atom transfer occurs. The liberated H (or D) atom is reflected from the ArD+(ArH+ and the products separate, being decelerated in the process by the attractive potential acting between them. This “polarization–reflection” model yields a reasonable value for the radius at which transfer occurs, and it accounts quantitatively for the magnitudes of, and isotopic effects on, the median product velocities. It also predicts the significant back scattering observed at very low as well as very high energies. With appropriate modification for the attractive potentials involved the model can provide a simple representation of direct reactions in general

Psychological distress in cancer patients assessed with an expert rating scale

The purpose of this study was to investigate psychosocial stress in a large sample of cancer patients using an expert rating scale. Specific aims were to analyse the relevance of setting variables (type of clinic, contact initiative, therapy) and gender. A total of 6365 patients were assessed in 105 institutions. Univariate and multivariate statistical analysis of setting variables indicated that patients treated in palliative care settings showed highest distress scores compared to patients recruited from hospitals and outpatient clinics (P<0.001). Significant differences were also found for contact initiative (P<0.001); lowest distress was found in patients who were recruited by routine contact. Patients who asked for psychosocial support or who were recruited by the medical staff showed the highest distress scores. The analysis of therapy groups showed that patients receiving radiotherapy or surgery were not more distressed than patients without therapy. The most distressing treatment was chemotherapy. Gender had differential effects on clinic type (P<0.001) and contact initiative (P<0.001) but not on treatment and diagnosis. Expert rating scales are an important complement for self-assessment questionnaires to evaluate psychological distress of cancer patients in psychosocial studies as well as in routine medical care