On Generating Binary Words Palindromically

We regard a finite word $u=u_1u_2\cdots u_n$ up to word isomorphism as an equivalence relation on $\{1,2,\ldots, n\}$ where $i$ is equivalent to $j$ if and only if $x_i=x_j.$ Some finite words (in particular all binary words) are generated by "{\it palindromic}" relations of the form $k\sim j+i-k$ for some choice of $1\leq i\leq j\leq n$ and $k\in \{i,i+1,\ldots,j\}.$ That is to say, some finite words $u$ are uniquely determined up to word isomorphism by the position and length of some of its palindromic factors. In this paper we study the function $\mu(u)$ defined as the least number of palindromic relations required to generate $u.$ We show that every aperiodic infinite word must contain a factor $u$ with $\mu(u)\geq 3,$ and that some infinite words $x$ have the property that $\mu(u)\leq 3$ for each factor $u$ of $x.$ We obtain a complete classification of such words on a binary alphabet (which includes the well known class of Sturmian words). In contrast for the Thue-Morse word, we show that the function $\mu$ is unbounded

Is the Medical Brain Drain Beneficial? Evidence from Overseas Doctors in the UK

The ¿beneficial brain drain¿ hypothesis suggests that skilled migration can be good for a sending countrybecause the incentives it creates for training increase that country¿s supply of skilled labour. To work, thishypothesis requires that the degree of screening of migrants by the host country is limited and that thepossibility of migration actually encourages home country residents to obtain education. We studied theimplications of doctors¿ migration by conducting a survey among overseas doctors in the UK. The resultssuggest that the overseas doctors who come to the UK are carefully screened and that only a minority of doctorsfrom developing countries considered the possibility of migration when they chose to obtain medical education.The incentive effect is thus probably not large enough to increase the skills-supply in developing countries.Doctors do, however, remit income to their home countries and many intend to return after completing theirtraining in the UK, so there could be benefits via these routes.brain drain, international labour market, professional labour markets, doctors, physicians,international migration

Optimal fidelity of teleportation of coherent states and entanglement

We study the Braunstein-Kimble protocol for the continuous variable teleportation of a coherent state. We determine lower and upper bounds for the optimal fidelity of teleportation, maximized over all local Gaussian operations for a given entanglement of the two-mode Gaussian state shared by the sender (Alice) and the receiver (Bob). We also determine the optimal local transformations at Alice and Bob sites and the corresponding maximum fidelity when one restricts to local trace-preserving Gaussian completely positive maps.Comment: 10 pages, 2 figure

Barrett’s esophagus and esophageal adenocarcinoma: from molecular pathogenesis to novel therapeutic targets

Despite latest improvements in diagnostics and therapeutics, esophageal cancer is still the sixth most frequent cause of death related to cancer worldwide. Patients that suffer from this cancer have very poor prognosis, with 5-year survival rates of 15-20%. This is mostly due to late clinical presentation with advance disease. Strikingly, especially in western countries, the incidence of the histologic subtype esophageal adenocarcinoma (EAC) increased dramatically over the past twenty years. Unfortunately, standard treatments, such as chemoradiotherapy and/or surgery, seem to be not effective. In the first part of this thesis, I’ve approached the study of molecular key events involved in the development of Barrett’s esophagus, one of the major risk factor associated with the development of EAC. Specifically, I’ve tried to understand the signalling pathways activated by the chronic gastro-esophageal reflux exposure, in order to unveil novel therapeutic targets at which preventive therapies can be directed. In the second part of this thesis I’ve focused on the immunobiology of EAC. I’ve tested novel methodologies for boosting the host’s anti-tumor immune response and, I’ve attempted to understand molecular mechanisms that can lead to tumor immune evasion. Only a deep understanding of the described molecular pathways can lead the way to the development of more effective therapeutic approaches, such as, immunotherapy

Action of HMGB1 on miR221/222 cluster in neuroblastoma cell lines

microRNA (miR/miRNA) are small non-coding RNAs that control gene expression at the post-transcriptional level by targeting mRNAs. Aberrant expression of miRNAs is often observed in different types of cancer. Specific miRNAs function as tumor suppressors or oncogenes and interfere with various aspects of carcinogenesis, including differentiation, proliferation and invasion. Upregulation of miRNAs 221 and 222 has been shown to induce a malignant phenotype in numerous human cancers via inhibition of phosphatase and tensin homolog (PTEN) expression. Neuroblastoma is the most common extracranial solid malignancy in children, which is characterized by cellular heterogeneity that corresponds to different clinical outcomes. The different cellular phenotypes are associated with different gene mutations and miRs that control genetic and epigenetic factors. For this reason miRs are considered a potential therapeutic target in neuroblastoma. The aim of the present study was to investigate the mechanisms by which extracellular high mobility group box 1 (HMGB1) promotes cell growth in neuroblastoma. SK-N-BE(2) and SH-SY5Y neuroblastoma derived cell lines were transfected with the antisense oligonucleotides, anti-miR-221 and -222, followed by treatment with HMGB1 to investigate the expression of the oncosuppressor PTEN. In this study, it was demonstrated that HMGB1, which is released by damaged cells and tumor cells, upregulates miR-221/222 oncogenic clusters in the two human neuroblastoma derived cell lines. The results revealed that the oncogenic cluster miRs 221/222 were more highly expressed by the most undifferentiated cell line [SK-N-BE(2)] compared with the the less tumorigenic cell line (SH-SY5Y) and that exogenous HMGB1 increases this expression. In addition, HMGB1 modulates PTEN expression via miR-221/222, as demonstrated by transiently blocking miR-221/222 with anti-sense oligonucleotides. These results may lead to the development of novel therapeutic strategies for neuroblastoma

Chapter 4 • Near-surface reflection surveying

In the geophysics of oil exploration and reservoir studies, the surface seismic method is the most commonly used method to obtain a subsurface model in 2 or 3 dimensions. This method plays an increasingly important role in soil investigations for geotechnical, hydrogeological and site characterization studies regarding seismic hazard issues. The goal of this book is to provide a practical guide, using examples from the field, to the application of seismic methods to surface imaging. After reviewing the current state of knowledge in seismic wave propagation, refraction and reflection seismic methods, the book aims to describe how seismic tomography and fullwave form inversion methods can be used to obtain seismic images of the subsurface. Through various synthetic and field examples, the book highlights the benefit of combining different sets of data: refracted waves with reflected waves, and body waves with surface waves. With field data targeting shallow structures, it shows how more accurate geophysical models can be obtained by using the proposed hybrid methods. Finally, it shows how the integration of seismic data (3D survey and VSP), logging data (acoustic logging) and core measurements, combined with a succession of specific and advanced processing techniques, enables the development of a 3D high resolution geological model in depth. In addition to these examples, the authors provide readers with guidelines to carry out these operations, in terms of acquisition, as well as processing and interpretation. In each chapter, the reader will find theoretical concepts, practical rules and, above all, actual application examples. For this reason, the book can be used as a text to accompany course lectures or continuing education seminars. This book aims to promote the exchange of information among geologists, geophysicists, and engineers in geotechnical fields

Chapter 1 • Wave propagation

In the geophysics of oil exploration and reservoir studies, the surface seismic method is the most commonly used method to obtain a subsurface model in 2 or 3 dimensions. This method plays an increasingly important role in soil investigations for geotechnical, hydrogeological and site characterization studies regarding seismic hazard issues. The goal of this book is to provide a practical guide, using examples from the field, to the application of seismic methods to surface imaging. After reviewing the current state of knowledge in seismic wave propagation, refraction and reflection seismic methods, the book aims to describe how seismic tomography and fullwave form inversion methods can be used to obtain seismic images of the subsurface. Through various synthetic and field examples, the book highlights the benefit of combining different sets of data: refracted waves with reflected waves, and body waves with surface waves. With field data targeting shallow structures, it shows how more accurate geophysical models can be obtained by using the proposed hybrid methods. Finally, it shows how the integration of seismic data (3D survey and VSP), logging data (acoustic logging) and core measurements, combined with a succession of specific and advanced processing techniques, enables the development of a 3D high resolution geological model in depth. In addition to these examples, the authors provide readers with guidelines to carry out these operations, in terms of acquisition, as well as processing and interpretation. In each chapter, the reader will find theoretical concepts, practical rules and, above all, actual application examples. For this reason, the book can be used as a text to accompany course lectures or continuing education seminars. This book aims to promote the exchange of information among geologists, geophysicists, and engineers in geotechnical fields