Exponential Random Graph Modeling for Complex Brain Networks

Exponential random graph models (ERGMs), also known as p* models, have been utilized extensively in the social science literature to study complex networks and how their global structure depends on underlying structural components. However, the literature on their use in biological networks (especially brain networks) has remained sparse. Descriptive models based on a specific feature of the graph (clustering coefficient, degree distribution, etc.) have dominated connectivity research in neuroscience. Corresponding generative models have been developed to reproduce one of these features. However, the complexity inherent in whole-brain network data necessitates the development and use of tools that allow the systematic exploration of several features simultaneously and how they interact to form the global network architecture. ERGMs provide a statistically principled approach to the assessment of how a set of interacting local brain network features gives rise to the global structure. We illustrate the utility of ERGMs for modeling, analyzing, and simulating complex whole-brain networks with network data from normal subjects. We also provide a foundation for the selection of important local features through the implementation and assessment of three selection approaches: a traditional p-value based backward selection approach, an information criterion approach (AIC), and a graphical goodness of fit (GOF) approach. The graphical GOF approach serves as the best method given the scientific interest in being able to capture and reproduce the structure of fitted brain networks

Tidal stream resource characterisation in progressive versus standing wave systems

© 2018 The Author(s) Characterisations of the tidal stream resource and its variability over various timescales are crucial for the development of the tidal stream energy industry. To date, no research has compared resource sensitivity in standing wave (when peak currents occur midway between high and low water) and progressive wave (where peak currents occur at high and low water) tidal systems. Here, we compare the flow regimes of standing wave versus progressive wave systems and the associated variations in tidal stream power with applications to device deployment options (floating-platform turbines versus bottom-mounted turbines). We use a validated 3D numerical model (ROMS) of a globally-significant tidal energy shelf sea region (Irish Sea), to test the hypotheses that the influence on potential extractable energy, and suitability for different devices, may be markedly different between these contrasting systems. Power density was also calculated and compared for floating versus bottom-mounted devices using in-situ current data (ADCPs) obtained from a standing wave site and a progressive wave site. We show that progressive wave systems are characterised by velocity-asymmetry over a tidal cycle (i.e. stronger peak flows at high water than at low water), leading to power-asymmetry. Such power asymmetry was shown to have more of an effect on floating device technology, where an assumed turbine depth tracks the sea surface, in contrast to bottom-mounted technology, where the hub height is fixed at a certain position above the sea bed. Shallow, high-flow regions where tidal range is large contained up to 2.5% more power density from bottom-mounted compared with floating turbines; however, there were areas where floating devices were exposed to higher mean currents over a tidal cycle. Standing wave systems, where flow asymmetry is minimised, did not particularly favour either technology. The results highlight the requirement for detailed resource assessments to consider the vertical plane, and are applicable to all potential tidal stream energy sites

Micrositing variability and mean flow scaling for marine turbulence in Ramsey Sound

We present turbulence results from two acoustic Doppler current profiler measurement campaigns carried out in Ramsey Sound at two locations within 50mof one another. The first measurements were taken in 2009 and the second in 2011; both include a complete spring–neap cycle. In this paper we characterise turbulence through turbulent kinetic energy (TKE) density and integral lengthscales and their relationships with one another and with mean flow parameters. We briefly describe the methods used to calculate these parameters. We find that a flood–ebb asymmetry is present in the data from both measurement campaigns, but although the flood tides are similar at both locations, the ebb tides are much more energetic in the 2011 data than the 2009 data. We suggest that this may be due to differences in seabed features between the two measurement locations. Dimensional analysis is employed to investigate how TKE scales with mean flow velocity; we find that the expected quadratic scaling is not well supported by the data at either measurement location. As a consequence, flows that have more energetic turbulence may instead appear to be less turbulent if judged by turbulence intensity. We investigate the correlation between lengthscales and TKE density and find that it is highly site-specific: it should not be assumed that for a given measurement location highly energetic turbulence is associated with larger flow structures or vice versa

The influence of age on the female/male ratio of treated incidence rates in depression

BACKGROUND: Poor data exist on the influence of psychosocial variables on the female/male ratio of depression because of the small number of cases and the resulting limited numbers of variables available for investigation. For this investigation a large number of first admitted depressed patients (N = 2599) was available which offered the unique opportunity to calculate age specific sex ratios for different marital and employment status categories. METHODS: Age and sex specific population based depression rates were calculated for first ever admissions for single year intervals. Moving averages with interpolated corrections for marginal values in the age distribution were employed. RESULTS: For the total group the female/male ratio of depression showed an inverted U-shape over the life-cycle. This pattern was influenced by the group of married persons, which showed a sex-ratio of 3:1 between the age of 30–50, but ratios of around 1:1 at younger and older ages. For not married persons the female/male ratio was already around 2:1 at the age of 18 and rose to 2.5:1 in mid-life and declined to 1 at around 55. The almost parallel decline of depression rates in employed men and women resulted in a female/male ratio of about 2:1 from age 18 to age 50 and became 1 after the age of 60. The female/male ratio among the not employed was about 1, in mid-life it became negative. CONCLUSIONS: Our analyses show that the gender-gap in first admitted depressed patients is age dependent and that psychosocial factors modify the sex ratio

Minimizing early relapse and maximizing treatment outcomes in hormone-sensitive postmenopausal breast cancer: efficacy review of AI trials

Breast cancer is one of the leading causes of cancer-related deaths in women. Regardless of prognosis, all women with breast cancer are at risk for early recurrence. Nearly 50% of early recurrences occur within 5 years of surgery, and they peak at 2 years after surgery in women treated with adjuvant tamoxifen. Most early recurrences are distant metastases, which strongly correlate with increased mortality. Treatments that mitigate the risk of early distant metastases (DM) are, therefore, likely to improve overall survival in women with early breast cancer (EBC). Aromatase inhibitors (AIs)—anastrozole, letrozole, and exemestane—have been investigated as alternatives to tamoxifen for adjuvant treatment of hormone receptor-positive (HR+) EBC in postmenopausal women (PMW). AIs are better at minimizing risk of early relapse compared with tamoxifen. However, it is not clear if preferential use of AIs over tamoxifen will benefit all PMW with HR+ EBC. The ability to subtype HR+ breast cancer on the basis of biomarkers predictive of response to AIs and tamoxifen would likely be key to determining the most beneficial hormonal treatment within patient subpopulations, but this process requires thorough investigation. Until then, adjuvant therapies that provide the greatest reduction in risk of DM should be considered for all PMW with HR+ EBC. This article reviews the clinical trials of AI adjuvant therapies for hormone-sensitive breast cancer, particularly in the context of how they compare with tamoxifen in minimizing the risk of relapse, occurrence of DM, and breast cancer-related deaths

Rare causes of scoliosis and spine deformity: experience and particular features

<p>Abstract</p> <p>Background</p> <p>Spine deformity can be idiopathic (more than 80% of cases), neuromuscular, congenital or neurofibromatosis-related. However, there are many disorders that may also be involved. We present our experience treating patients with scoliosis or other spine deformities related to rare clinical entities.</p> <p>Methods</p> <p>A retrospective study of the records of a school-screening study in North-West Greece was performed, covering a 10-year period (1992–2002). The records were searched for patients with deformities related to rare disorders. These patients were reviewed as regards to characteristics of underlying disorder and spine deformity, treatment and results, complications, intraoperative and anaesthesiologic difficulties particular to each case.</p> <p>Results</p> <p>In 13 cases, the spine deformity presented in relation to rare disorders. The underlying disorder was rare neurological disease in 2 cases (Rett syndrome, progressive hemidystonia), muscular disorders (facioscapulohumeral muscular dystrophy, arthrogryposis) in 2 patients, osteogenesis imperfecta in 2 cases, Marfan syndrome, osteopetrosis tarda, spondyloepiphyseal dysplasia congenita, cleidocranial dysplasia and Noonan syndrome in 1 case each. In 2 cases scoliosis was related to other congenital anomalies (phocomelia, blindness). Nine of these patients were surgically treated. Surgery was avoided in 3 patients.</p> <p>Conclusion</p> <p>This study illustrates the fact that different disorders are related with curves with different characteristics, different accompanying problems and possible complications. Investigation and understanding of the underlying pathology is an essential part of the clinical evaluation and preoperative work-up, as clinical experience at any specific center is limited.</p

Association of shared decision-making with type of breast cancer surgery: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Although some studies examined the association between shared decision-making (SDM) and type of breast cancer surgery received, it is little known how treatment decisions might be shaped by the information provided by physicians. The purpose of this study was to identify the associations between shared decision making (SDM) and surgical treatment received.</p> <p>Methods</p> <p>Questionnaires on SDM were administered to 1,893 women undergoing primary curative surgery for newly diagnosed stage 0-II localized breast cancer at five hospitals in Korea. Questions included being informed on treatment options and the patient's own opinion in decision-making.</p> <p>Results</p> <p>Patients more likely to undergo mastectomy were those whose opinions were respected in treatment decisions (adjusted odds ratio, aOR), 1.40; 95% confidence interval (CI), 1.14-1.72) and who were informed on chemotherapy (aOR, 2.57; CI, 2.20-3.01) or hormone therapy (aOR, 2.03; CI, 1.77-2.32). In contrast, patients less likely to undergo mastectomy were those who were more informed on breast surgery options (aOR, 0.34; CI, 0.27-0.42). In patients diagnosed with stage 0-IIa cancer, clinical factors and the provision of information on treatment by the doctor were associated with treatment decisions. In patients diagnosed with stage IIb cancer, the patient's opinion was more respected in treatment decisions.</p> <p>Conclusion</p> <p>Our population-based study suggested that women's treatment decisions might be shaped by the information provided by physicians, and that women might request different information from their physicians based on their preferred treatment options. These results might need to be confirmed in other studies of treatment decisions.</p