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The ability of populations to undergo adaptive evolution depends on the presence of quantitative genetic variation for ecologically important traits. Although molecular measures are widely used as surrogates for quantitative genetic variation, there is controversy about the strength of the relationship between the two. To resolve this issue, we carried out a meta-analysis based on 71 datasets. The mean correlation between molecular and quantitative measures of genetic variation was weak (r = 0.217). Furthermore, there was no significant relationship between the two measures for life-history traits (r = -0.11) or for the quantitative measure generally considered as the best indicator of adaptive potential, heritability (r = -0.08). Consequently, molecular measures of genetic diversity have only a very limited ability to predict quantitative genetic variability. When information about a population's short-term evolutionary potential or estimates of local adaptation and population divergence are required, quantitative genetic variation should be measured directly.

The PACS committee plays a crucial role in attaining successful outcomes from a PACS implementation. However, most radiology departments do not organize and manage their PACS committees well. This has resulted in poor outcomes and inability to realize projected benefits and return on investment. Ideally, there are two PACS committees: a high-level strategic committee that aligns the goals for the PACS with institutional initiatives, and an operational PACS committee that makes a hands-on approach to the project and manages the entire PACS program. The chairman of radiology, an assigned radiologist or the radiology administrator heads both PACS committees. The strategic PACS committee consists of senior people from information systems, strategic and operational planning, radiology, physicians, nursing, critical care, and other related departments in the hospital. The operational PACS committee consists of people directly involved in radiology operations including the chief of radiology, radiology administrator, technologists, file room manager and other personnel whose daily routines will be affected by the PACS implementation. The operational PACS committee manages the PACS program from initial planning through the post-installation period. Committee tasks include: developing an implementation plan, establishing goals and objectives, conducting a cost/benefits analysis, developing functional specifications, generating an RFP, managing vendor selection and contracting, preparing the site for installation, performing project management functions, conducting acceptance testing, overseeing training, and evolving the PACS operations to meet predicted outcomes.

The evolution of senescence may be explained by two different, but not mutually exclusive, genetic mechanisms. The antagonistic pleiotropy hypothesis predicts that senescence is a consequence of the fixation of alleles with pleiotropic effects favouring early life fitness, but bearing a cost in later life. The mutation-accumulation hypothesis attributes senescence to the accumulation of deleterious mutations with late-acting effects on fitness in mutation-selection balance. Experiments were carried out on the housefly, Musca domestica, in which large and small populations were maintained so that reproduction was limited to four or five days after reaching sexual maturity. Longevity declined significantly under the husbandry protocol and was largely the same in large and small populations; this is consistent with the random accumulation of deleterious alleles affecting longevity under curtailed life span, although laboratory adaptation cannot be ruled out entirely as a causal mechanism. An analysis of life-history data did not provide evidence for a trade-off between longevity and age at sexual maturity, developmental time, or dry body weight, but there was an apparent trade-off between longevity and early progeny production, in support of antagonistic pleiotropy.

When planning a picture archiving and communications system (PACS) implementation and determining which equipment will be implemented in earlier and later phases, collection and analysis of selected data will aid in setting implementation priorities. If baseline data are acquired relative to performance objectives, the same information used for implementation planning can be used to measure performance improvement and outcomes. The main categories of data to choose from are: (1) financial data; (2) productivity data; (3) operational parameters; (4) clinical data; and (5) information about customer satisfaction. In the authors' experience, detailed workflow data have not proved valuable in measuring PACS performance and outcomes. Reviewing only one category of data in planning will not provide adequate basis for targeting operational improvements that will lead to the most significant gains. Quality improvement takes into account all factors in production: human capacity, materials, operating capital and assets. Once we have identified key areas of focus for quality improvement in each phase, we can translate objectives into implementation requirements and finally into detailed functional and performance requirements. Here, Integration Resources reports its experience measuring PACS performance relative to phased implementation strategies for three large medical centers. Each medical center had its own objectives for overcoming image management, physical/geographical, and functional/technical barriers. The report outlines (1) principal financial and nonfinancial measures used as performance indicators; (2) implementation strategies chosen by each of the three medical centers; and (3) the results of those strategies as compared with baseline data.

Picture archiving and communication systems (PACS) is a complex and vast subject, about which much has been written. A Visual Guide to PACS is an overview of the subject presented as an efficient reference for hospital and department administrators planning for and implementing PACS. A Visual Guide to PACS is adapted from presentation materials developed by Integration Resources/GORCA to capsulize issues relating to PACS. The authors aim to communicate the broad parameter and some of the complexity of the subject.

This study examined the mediating role of anxiety in the self-reports of somatic complaints in 96 depressed adolescent inpatients. Sixty-four subjects with major depressive episodes and comorbid anxiety disorders (MDE-A) determined from the Diagnostic Interview for Children and Adolescents--Revised (DICA-R) reported significantly more somatic complaints than 32 adolescents having major depressive episodes without comorbid anxiety (MDE). An analysis of covariance demonstrated that, with anxiety symptoms controlled, MDE and MDE-A groups did not differ significantly in somatic complaints. A hierarchical multiple-regression analysis revealed that, with demographic and anxiety symptoms controlled, depressive symptoms did not contribute to the explanation or prediction of somatic complaints. The results suggest that anxious, but not depressive symptoms, are independently associated with somatic complaints. The results are discussed in light of new affective models of psychopathology.

A patient with osteomyelitis of the lower thoracic spine is reported in whom computed tomography (CT) revealed a large false aneurysm of the descending aorta. Useful radiological signs of the diagnosis are described, namely a thin aneurysm wall, a multilobulated margin and deformity of the aneurysm by adjacent vascular and osseous structures. Mycotic aneurysms of the aorta have a high mortality and the CT demonstration of a pseudoaneurysm has a vital role in management.

Four patients with seminoma of the testis and coexisting horseshoe kidney are presented. Three patients had stage one disease, which would conventionally be managed by abdominal nodal irradiation. However, because of the risk of radiation nephritis, a surveillance policy was adopted with regular computed tomography (CT). Two of these three patients have relapsed and are disease free after chemotherapy. The fourth patient had Stage IIC disease which initially responded to combined radiotherapy and chemotherapy. This patient's disease relapsed and he died despite further treatment. Because of the altered retroperitoneal anatomy, CT interpretation must be made with special care.

A patient with a congenitally absent uterus and a single pelvic kidney presented with recurrent pain in the left iliac fossa. This proved to be due to a prolapsed left ovary.

Three patients who were evaluated by computed tomography (CT) for possible recurrent tumour of the cervix are described. Two had proven carcinoma and the third had non-Hodgkin's lymphoma of the cervix. In each, soft tissue masses in the iliac fossa, close to the iliopsoas muscles, were demonstrated. The position, shape, symmetry and, in one patient, the presence of surgical clips led to the correct diagnosis that these soft tissue masses were normal ovaries which had been moved out of the true pelvis at the time of hysterectomy. Such ovarian conservation creates a potential cause of error as the ovaries can then simulate enlarged nodal masses.