Nonlinear resonant wave interaction in vacuum

The basic equations governing propagation of electromagnetic and gravitational waves in vacuum are nonlinear. As a consequence photon-photon interaction as well as photon-graviton interaction can take place without a medium. However, resonant interaction between less than four waves cannot occur in vacuum, unless the interaction takes place in a bounded region, such as a cavity or a waveguide. Recent results concerning resonant wave interaction in bounded vacuum regions are reviewed and extended.Comment: 8 pages, 1 figure; Talk given at ITCPP03, Santorini, Greece (2003

Forecasting Realized Volatility Using A Nonnegative Semiparametric Model

This paper introduces a parsimonious and yet flexible nonnegative semiparametric model to forecast financial volatility. The new model extends the linear nonnegative autoregressive model of Barndorff-Nielsen & Shephard (2001) and Nielsen & Shephard (2003) by way of a power transformation. It is semiparametric in the sense that the dependency structure and distributional form of its error component are left unspecified. The statistical properties of the model are discussed and a novel estimation method is proposed. Simulation studies validate the new estimation method and suggest that it works reasonably well in finite samples. The out-of-sample performance of the proposed model is evaluated against a number of standard methods, using data on S&P 500 monthly realized volatilities. The competing models include the exponential smoothing method, a linear AR(1) model, a log-linear AR(1) model, and two long-memory ARFIMA models. Various loss functions are utilized to evaluate the predictive accuracy of the alternative methods. It is found that the new model generally produces highly competitive forecasts.Autoregression, nonlinear/non-Gaussian time series, realized volatility, semiparametric model, volatility forecast

Forecasting Realized Volatility Using A Nonnegative Semiparametric Model

This paper introduces a parsimonious and yet flexible nonnegative semiparametric model to forecast financial volatility. The new model extends the linear nonnegative autoregressive model of Barndorff-Nielsen & Shephard (2001) and Nielsen & Shephard (2003) by way of a power transformation. It is semiparametric in the sense that the dependency structure and distributional form of its error component are left unspecified. The statistical properties of the model are discussed and a novel estimation method is proposed. Simulation studies validate the new estimation method and suggest that it works reasonably well in finite samples. The out-of-sample performance of the proposed model is evaluated against a number of standard methods, using data on S&P 500 monthly realized volatilities. The competing models include the exponential smoothing method, a linear AR(1) model, a log-linear AR(1) model, and two long-memory ARFIMA models. Various loss functions are utilized to evaluate the predictive accuracy of the alternative methods. It is found that the new model generally produces highly competitive forecasts.Autoregression, nonlinear/non-Gaussian time series, realized volatility, semiparametric model, volatility forecast.

An Evaluation of Data Sources for Entry Decision Support in Rapid-Onset Disasters

If time-sensitive relief is to be dispatched to a far-away location, the decision to do so – the “entry” decision – has to be taken within hours after the disaster for the relief to make an impact. This paper aims to identify which information sources that become available to the decision maker at what time after a potential disaster, and to establish how the provided information can be best utilized based on its inherent and accumulated quality. The research encompasses 46 case studies in central Asia in the period from 1993 to 2003. The study makes clear that a decision-maker will only benefit from satellite imagery if the time required to deliver a digested product to the decision maker is reduced to a matter of hours or if the area of interest is so remote or widespread that the time necessary for on-site reports exceeds that of acquiring and interpreting remotely sensed imagery. In conclusion, model-based decision support systems are important since they provide an early alert that enables other sources to quicker provide information that is more refined.JRC.G.2-Support to external securit

Total Quality Management in Mine Action

Here the author relays the relationship between information management and quality management and how the latter depends on the efficiency of the former. With increasingly better tools for mine-action programs in the field of information management, such as the new versions of the Information Management System for Mine Action, the author discusses how mine action will move into a new age of information technology that will allow for better proficiency in the field

Towards a dermal papilla specific expression system in mice

Abstract Stem cells hold great promise for regenerative medicine. In order to realize the potential of stem cell-based therapies, it is highly required to understand the basic mechanisms of stem cell regulation and transform such knowledge into medical applications. However, understanding stem cell regulations is still challenging due to technical difficulties in studying stem cell biology. The hair follicle is a continuously regenerating mini-organ, in which keratinocyte and melanocyte stem cells cooperate to achieve periodical cycles of pigmented hair formation. The mouse hair follicle provides an ideal model by which to investigate molecular basis of stem cell regulation as defective molecular regulation results in abnormal hair formation, a phenotype easily recognized by appearance. It has been widely appreciated that the regulation of these stem cells is mediated through the epithelial-mesenchymal interactions where a cluster of mesenchymal cells, known as the dermal papilla, plays a key role. Here we aim to establish a system manipulating genes in dermal papilla to identify genes involved in the stem cell regulation. To this end, the purpose of this study is to identify a promoter element permitting stable and specific dermal papilla transgene expression in mice. In this report, by integrating BAC transgenesis and transposon-meditated gene delivery systems, we establish a simple pipeline to identify a gene expression element enabling dermal papilla-specific genetic modifications.Popular science summary: Healing: what we can learn from white mice Stem cells are a cell type responsible for building the body. They are the ancestor cells from which all the cells making up the body’s tissues are created. Stem cells play an important role in maintaining the body in shape by repairing damages as they occur during life. We believe that if we had a better understanding of how these stem cells signal and talk within the body we could persuade them to heal more damages than they normally do. This could have enormous potential to help many people suffering from degenerative diseases such as Parkinson disease, Alzheimer disease, or muscular dystrophy to return to a normal life. The stem cells building mouse fur In mice the fur is built by two types of stem cells inside the mouse hair follicle. They are called keratinocytes and melanocytes. The keratinocytes build the hair and the melanocytes provide it with color. These stem cells take orders from other key operator cells called the dermal papilla, located inside the follicle, which instructs the stem cells when to make and when to shed the hairs. Thus, the dermal papilla controls the hair growth and color. This gives potential to the dermal papilla to become an attractive model system to investigate which molecules tell stem cells to do what. If one important molecule is missing, the stem cells would no longer hear that signal and stop working. If such a molecule would be mutated in mice they would become either hairless or white which is easily recognized by strange hair coat appearance. Such characteristics of the dermal papilla can be utilized to quickly screen many molecules to identify important ones for the stem cell regulation. To do this we need to find a DNA element which is only used in the dermal papilla so that we can remove signaling molecules without changing a lot of other things around the mouse. To find it we made a huge DNA construct called bacterial artificial chromosome (BAC) carrying a fluorescent protein gene called GFP under the control of a promoter we believe to be used only inside the dermal papilla. Cells using this promoter would then glow in green. To make the construct work, it needs to be inserted into the host genome. The GFP alone is very small and is very easily inserted into the host genome. However, the larger construct that we constructed needed a little help getting into the genome. Therefore we used a special protein called transposase which is an enzyme that cuts DNA from one place and pastes it in another. To test if this approach worked, we confirmed that our GFP construct could be inserted into the genome of human cells. Next we need to insert it into the mouse genome. This would allow us to see what parts of the mouse are glowing and if only the dermal papilla is green we could use our system to learn more about stem cell signalling. Supervisor: Masatake Osawa Master´s Degree Project - Cell and Molecular Biology 30 credits 2013 Department of Biology, Lund University, Department of Molecular Design and Synthesis, Regeneration Technology, Regeneration and Advanced Medical Sciences, Graduate School of Medicine Gifu Universi

Information-management Activities at the GICHD

Two years have passed since a new strategy was adopted for the information-management section at the Geneva International Centre for Humanitarian Demining. A significant amount of work was completed since then, and the support and quality of the Information Management System for Mine Action has improved. The new focus on information management in a broader sense, not just limited to databases and software, has enabled country programs to collect relevant information for more effective demining operations. Although much work remains, a few key developments deserve mentioning

Theory and practice of customer-related improvements: a systematic literature review

Customers are vital to any organization and system, and must therefore be considered when seeking to improve. However, how to improve with regard to the customer, is not clear, and the knowledge is spread over several research fields, making it difficult for researchers and practitioners to comprehend. The purpose of this literature review is to show how customer-related improvements are described in the literature and how the research is performed. 666 articles were screened, resulting in 99 coded and analysed articles. The study concludes that there is a lack of understanding when it comes to the process of how to improve and that both practitioners and academics should focus more on the system level. It is also seen that by involving the customer in the improvement process, the improvement is more likely to succeed. The article concludes that there is a need for future research which are conceptual, longitudinal, and are addressing actual improvements, not just potential. From the practitioners\u27 point of view, the article is proposing an increased focus on customer-related improvements which address aspects concerning people, such as employee competence and work environment, and reward systems, rather than strategy and processes to improve the potential benefits

Adipose markers of metabolic outcome after weight loss

Adipose tissue is closely linked to metabolic disturbances in obesity. Bariatric surgery such as roux-en-Y gastric bypass (RYGB) remains the most effective treatment of obesity and obesity-related disease. More factors than fat mass per se determine the metabolic complications of obesity, including alterations in fat cell size, body fat distribution, adipose protein release, inflammation and lipolysis. The aim of this thesis was to further characterize the relationship between adipose tissue characteristics and metabolic parameters before and after weight loss, and to investigate if adipose phenotype can predict metabolic improvement after weight loss. Study I. At any given fat mass, adipose tissue may constitute of many small fat cells (hyperplasia) or few but large fat cells (hypertrophy). This latter morphology is associated with worse metabolic profile. Study I examined if adipose morphology, i.e. hyperplasia or hypertrophy, could predict improved insulin sensitivity after weight loss. Abdominal subcutaneous adipose biopsies were performed before weight loss by diet or RYGB. Body fat mass was measured by dual-energy x-ray absorptiometry (DXA) or bioimpedance and insulin sensitivity assessed by homeostasis model assessment of insulin resistance (HOMA-IR). Results showed a higher improvement in HOMA-IR in patients with hypertrophy. Study II. The degree of improvement in metabolic profile and adipose tissue phenotype after weight loss is in relation to weight stable controls is not fully understood. In this study, women that had undergone RYGB were compared with a weight stable matched control group. Subjects that had undergone RYGB had lower HOMA-IR, better lipid profile and higher adiponectin levels and their adipose tissue was characterized by smaller fat cells, less visceral fat and lower secretion of tumor necrosis factor α (TNF-α) than controls. Study III. Herein, the CC chemokine ligand 18 (CCL18) was examined in adipose tissue. CCL18 was found to be released from adipose tissue in a time dependent manner. M2 macrophages were the primary source of CCL18. Serum- and adipose secreted levels of CCL18 correlated with metabolic risk factors in women. We could not demonstrate effects of CCL18 on adipocyte expression of inflammatory or extracellular matrix proteins in vitro. Study IV. The aim of this study was to investigate if body fat mass distribution measured by DXA or simple anthropometric measures could predict improved metabolic profile or weight loss after RYGB. Android/gynoid fat mass ratio and waist-to hip ratio could predict improved HOMA-IR, and BMI and body fat percentage could predict weight loss. DXA measures and simple anthropometric measures performed equally well, indicating a limited value for DXA to predict metabolic outcome after RYGB. Conclusions: Adipose tissue morphology and body fat distribution can predict improved insulin sensitivity following weight loss. Metabolic and adipose phenotype improves beyond the control state after RYGB. CCL18 is released from M2 macrophages in adipose tissue, and adipose released and circulating levels correlate with metabolic risk markers in women