Iteratively regularized Newton-type methods for general data misfit functionals and applications to Poisson data

We study Newton type methods for inverse problems described by nonlinear operator equations $F(u)=g$ in Banach spaces where the Newton equations $F'(u_n;u_{n+1}-u_n) = g-F(u_n)$ are regularized variationally using a general data misfit functional and a convex regularization term. This generalizes the well-known iteratively regularized Gauss-Newton method (IRGNM). We prove convergence and convergence rates as the noise level tends to 0 both for an a priori stopping rule and for a Lepski{\u\i}-type a posteriori stopping rule. Our analysis includes previous order optimal convergence rate results for the IRGNM as special cases. The main focus of this paper is on inverse problems with Poisson data where the natural data misfit functional is given by the Kullback-Leibler divergence. Two examples of such problems are discussed in detail: an inverse obstacle scattering problem with amplitude data of the far-field pattern and a phase retrieval problem. The performence of the proposed method for these problems is illustrated in numerical examples

Quantifying The Causes of Differences in Tropospheric OH within Global Models

The hydroxyl radical (OH) is the primary daytime oxidant in the troposphere and provides the main loss mechanism for many pollutants and greenhouse gases, including methane (CH4). Global mean tropospheric OH differs by as much as 80% among various global models, for reasons that are not well understood. We use neural networks (NNs), trained using archived output from eight chemical transport models (CTMs) that participated in the POLARCAT Model Intercomparison Project (POLMIP), to quantify the factors responsible for differences in tropospheric OH and resulting CH4 lifetime (τCH4) between these models. Annual average τCH4, for loss by OH only, ranges from 8.0–11.6 years for the eight POLMIP CTMs. The factors driving these differences were quantified by inputting 3-D chemical fields from one CTM into the trained NN of another CTM. Across all CTMs, the largest mean differences in τCH4 (ΔτCH4) result from variations in chemical mechanisms (ΔτCH4 = 0.46 years), the photolysis frequency (J) of O3→O(1D) (0.31 years), local O3 (0.30 years), and CO (0.23 years). The ΔτCH4 due to CTM differences in NOx (NO + NO2) is relatively low (0.17 years), though large regional variation in OH between the CTMs is attributed to NOx. Differences in isoprene and J(NO2) have negligible overall effect on globally averaged tropospheric OH, though the extent of OH variations due to each factor depends on the model being examined. This study demonstrates that NNs can serve as a useful tool for quantifying why tropospheric OH varies between global models, provided essential chemical fields are archived

Community uptake of safe storage boxes to reduce self-poisoning from pesticides in rural Sri Lanka

BACKGROUND: Acute poisoning by agricultural pesticides is a well established global public health problem. Keeping pesticides under safe storage is now promoted as a potential way to reduce the number of severe poisoning cases. However, there have been no published studies documenting the feasibility of such an approach. Therefore, the objective of the study presented here was to determine community perceptions and use of in-house safe storage boxes for pesticides in rural Sri Lanka. METHODS: Boxes with a lock, to be used for the in-house safe storage of pesticides, were distributed to 200 randomly selected farming households in two agricultural communities. A baseline survey determined pesticide storage practices and household characteristics prior to distribution. The selected households were encouraged to make use of the box at community meetings and during a single visit to each household one month after distribution. No further encouragement was offered. A follow-up survey assessed storage practices seven months into the project. RESULTS: Following the distribution of the boxes the community identified a number of benefits including the protection of pesticide containers against exposure from the rain and sun and a reduced risk of theft. Data were analysed for 172 households that reported agricultural use of pesticides at follow-up. Of these, 141 (82%) kept pesticides in the house under lock against 3 (2%) at baseline. As expected, the distribution of boxes significantly reduced the number of households storing pesticides in the field, from 79 (46%) at baseline to 4 (2%) at follow-up. There was a significant increase in the number of households keeping pesticides safe from children between baseline (64%) and seven months after the distribution of boxes (89%). The same was true for adults although less pronounced with 51% at baseline and 66% at follow-up. CONCLUSION: The farming community appreciated the storage boxes and made storage of pesticides safer, especially for children. It seems that additional, intensive promotion is needed to ensure that pesticide boxes are locked. The introduction of in-house safe storage boxes resulted in a shift of storage into the farmer's home and away from the field and this may increase the domestic risk of impulsive self-poisoning episodes. This increased risk needs attention in future safe storage promotion projects

Improving the management of pain from advanced cancer in the community: study protocol for a pragmatic multi-centre randomised controlled trial

Introduction: For patients with advanced cancer, research shows that pain is frequent, burdensome and undertreated. Evidence-based approaches to support cancer pain management have been developed but have not been implemented within the context of the UK National Health Service. This protocol is for a pragmatic multi-centre randomised controlled trial to assess feasibility, acceptability, effectiveness and cost effectiveness for a multi-component intervention for pain management in patients with advanced cancer. Methods and Analysis: This trial will assess the feasibility of implementation and uptake of evidence based interventions, developed and piloted as part of the IMPACCT Programme grant, into routine clinical practice and determine whether there are potential differences with respect to patient rated pain, patient pain knowledge and experience, healthcare use, quality of life, and cost effectiveness. 160 patients will receive either the intervention (usual care plus supported self-management) delivered within the oncology clinic and palliative care services by locally assigned community palliative care nurses, consisting of a self-management educational intervention and eHealth intervention for routine pain assessment and monitoring; or usual care. The primary outcomes are to assess implementation and uptake of the interventions, and differences in terms of pain severity. Secondary outcomes include pain interference, participant pain knowledge and experience, and cost effectiveness. Outcome assessment will be blinded and patient reported outcome measures collected via post at 6 and 12 weeks following randomisation. Ethics and Dissemination: This RCT has the potential to significantly influence NHS service delivery to community based patients with pain from advanced cancer. We aim to provide definitive evidence of whether two simple interventions delivered by community palliative care nurse in palliative care that support-self-management are clinically and cost effective additions to standard community palliative care

The Red Sea, Coastal Landscapes, and Hominin Dispersals

This chapter provides a critical assessment of environment, landscape and resources in the Red Sea region over the past five million years in relation to archaeological evidence of hominin settlement, and of current hypotheses about the role of the region as a pathway or obstacle to population dispersals between Africa and Asia and the possible significance of coastal colonization. The discussion assesses the impact of factors such as topography and the distribution of resources on land and on the seacoast, taking account of geographical variation and changes in geology, sea levels and palaeoclimate. The merits of northern and southern routes of movement at either end of the Red Sea are compared. All the evidence indicates that there has been no land connection at the southern end since the beginning of the Pliocene period, but that short sea crossings would have been possible at lowest sea-level stands with little or no technical aids. More important than the possibilities of crossing the southern channel is the nature of the resources available in the adjacent coastal zones. There were many climatic episodes wetter than today, and during these periods water draining from the Arabian escarpment provided productive conditions for large mammals and human populations in coastal regions and eastwards into the desert. During drier episodes the coastal region would have provided important refugia both in upland areas and on the emerged shelves exposed by lowered sea level, especially in the southern sector and on both sides of the Red Sea. Marine resources may have offered an added advantage in coastal areas, but evidence for their exploitation is very limited, and their role has been over-exaggerated in hypotheses of coastal colonization

Primary temporal bone angiosarcoma: a case report.

We present a rare case of temporal bone angiosarcoma diagnosed in a 26-year-old female patient at 36 week of pregnancy. The patient was referred with a 2 months history of left otalgia and tinnitus with a tender swelling above the mastoid. Cranial imaging studies showed a 7 x 5 x 4 cm hypervascularized mass located in the left middle fossa with lysis of the temporal bone and extension to the subcutis. After the baby was delivered by caesarean section, the patient entered the oncology protocol. Selective embolization of the feeding vessels was followed by gross total surgical resection using a combined supra- and infra-tentorial approach. Pathological findings were those of a poorly differentiated, highly malignant sarcoma with a large epitheloid component and immunohistochemical evidence of endothelial differentiation (CD31, Factor VIII related antigen, CD34), consistent with an angiosarcoma with epitheloid features. No extra-cranial tumor was found after extensive staging. The patient received adjuvant radiotherapy followed by a course of chemotherapy consisting of 6 cycles of paclitaxel. At 15 months follow-up, she developed multiple distant metastasis to a left postauricular lymph node and to the lungs and ribs. The patient was given a second line chemotherapy using doxorubicine and ifosfamide. Despite an initial good response, she died with metastatic disease 26 months after diagnosis. We present a rare case of primary temporal bone angiosarcoma and report our experience with a multimode therapeutic approach combining surgery, radiotherapy and chemotherapy.Peer reviewe

Diffusion of an e-learning programme among Danish General Practitioners: A nation-wide prospective survey

<p>Abstract</p> <p>Background</p> <p>We were unable to identify studies that have considered the diffusion of an e-learning programme among a large population of general practitioners. The aim of this study was to investigate the uptake of an e-learning programme introduced to General Practitioners as part of a nation-wide disseminated dementia guideline.</p> <p>Methods</p> <p>A prospective study among all 3632 Danish GPs. The GPs were followed from the launching of the e-learning programme in November 2006 and 6 months forward. Main outcome measures: Use of the e-learning programme. A logistic regression model (GEE) was used to identify predictors for use of the e-learning programme.</p> <p>Results</p> <p>In the study period, a total of 192 different GPs (5.3%) were identified as users, and 17% (32) had at least one re-logon. Among responders at first login most have learnt about the e-learning programme from written material (41%) or from the internet (44%). A total of 94% of the users described their ability of conducting a diagnostic evaluation as good or excellent. Most of the respondents used the e-learning programme due to general interest (90%). Predictors for using the e-learning programme were Males (OR = 1.4, 95% CI 1.1; 2.0) and members of Danish College of General Practice (OR = 2.2, 95% CI 1.5; 3.1), whereas age, experience and working place did not seem to be influential.</p> <p>Conclusion</p> <p>Only few Danish GPs used the e-learning programme in the first 6 months after the launching. Those using it were more often males and members of Danish College of General Practice. Based on this study we conclude, that an active implementation is needed, also when considering electronic formats of CME like e-learning.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier: NCT00392483.</p

How Do Bacteria Know They Are on a Surface and Regulate Their Response to an Adhering State?

Bacteria adhere to virtually all natural and synthetic surfaces [1,2]. Although there are a number of different reasons as to why bacteria adhere to a surface, the summarizing answer is brief: ‘‘Adhesion to a surface is a survival mechanism for bacteria’’. Nutrients in aqueous environments have the tendency to accumulate at surfaces [1,3], giving adhering bacteria a benefit over free floating, so-called planktonic ones. This is why mountain creeks may contain crystal clear, drinkable water, while stepping stones underneath the water may be covered with a slippery film of adhering microbes. In the oral cavity, adhesion to dental hard and soft tissues is life-saving to the organisms, because microbes that do not manage to adhere and remain planktonic in saliva are swallowed with an almost certain death in the gastrointestinal tract. Bacterial adhesion is generally recognized as the first step in biofilm formation, and for the human host, the ability of

Proliferating versus differentiating stem and cancer cells exhibit distinct midbody-release behaviour

The central portion of the midbody, a cytoplasmic bridge between nascent daughter cells at the end of cell division, has generally been thought to be retained by one of the daughter cells, but has, recently, also been shown to be released into the extracellular space. The significance of midbody-retention versus -release is unknown. Here we show, by quantitatively analysing midbody-fate in various cell lines under different growth conditions, that the extent of midbody-release is significantly greater in stem cells than cancer-derived cells. Induction of cell differentiation is accompanied by an increase in midbody-release. Knockdown of the endosomal sorting complex required for transport family members, Alix and tumour-suppressor gene 101, or of their interaction partner, centrosomal protein 55, impairs midbody-release, suggesting mechanistic similarities to abscission. Cells with such impaired midbody-release exhibit enhanced responsiveness to a differentiation stimulus. Taken together, midbody-release emerges as a characteristic feature of cells capable of differentiation