Enhancement of the Deuteron-Fusion Reactions in Metals and its Experimental Implications

Recent measurements of the reaction d(d,p)t in metallic environments at very low energies performed by different experimental groups point to an enhanced electron screening effect. However, the resulting screening energies differ strongly for divers host metals and different experiments. Here, we present new experimental results and investigations of interfering processes in the irradiated targets. These measurements inside metals set special challenges and pitfalls which make them and the data analysis particularly error-prone. There are multi-parameter collateral effects which are crucial for the correct interpretation of the observed experimental yields. They mainly originate from target surface contaminations due to residual gases in the vacuum as well as from inhomogeneities and instabilities in the deuteron density distribution in the targets. In order to address these problems an improved differential analysis method beyond the standard procedures has been implemented. Profound scrutiny of the other experiments demonstrates that the observed unusual changes in the reaction yields are mainly due to deuteron density dynamics simulating the alleged screening energy values. The experimental results are compared with different theoretical models of the electron screening in metals. The Debye-H\"{u}ckel model that has been previously proposed to explain the influence of the electron screening on both nuclear reactions and radioactive decays could be clearly excluded.Comment: 22 pages, 12 figures, REVTeX4, 2-column format. Submitted to Phys. Rev. C; accepte

Medically unexplained symptoms, illness perception and childhood experience in neurology outpatients

AbstractObjectives: Up to one third of patients presenting to neurology outpatients clinics have medically unexplained symptoms, but the aetiology of such symptoms is not well understood. In the current study we sought to investigate the role of anxiety, depression, cognitive factors and early experience in the development of medically unexplained symptoms.Method: Fifty-seven new patients presenting to a neurology outpatients clinic were studied. Demographic details were recorded and a Hospital Anxiety and Depression Scale, an Illness Perception Questionnaire, and a Childhood Development Questionnaire were administered. An assessment was made by trained medical investigators as to whether the patients symptoms were medically unexplained or accounted for by organic pathology.Results: We found that 17 out of 56 patients (30%) had medically unexplained symptoms. Such patients complained of a greater number of symptoms, were more anxious, were more likely to have a past history of depression, and were more likely to attribute their illness to stress than patients with a presumed organic basis for their disease. They were also more likely to have been in foster care as children. High levels of depression and anxiety were strongly associated with the number of physical symptoms and the perceived negative consequences of the illness.Conclusions: The recognition and treatment of anxiety and depressive disorders may contribute to the management of patients with medically unexplained symptoms. Open discussion of beliefs regarding aetiology are also likely to be of benefit regardless of the presence or absence of organic pathology.</jats:p