bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonrandomness of D‐group chromosomes involved in centric‐fusion translocation
Authors: Krmpotic Eva , Choi Sun Young , Grossman Aaron
Published: June 2009

Ten members of two families with D/G translocation, three members of a family with D/D translocation, and one patient with non‐familial and one with apparently non‐familial D/D translocation were examined. The trdnslocation chromosomes were identified by SH‐thymidine labeling and autoradio‐graphy as 14q21q and 13q14q, respectively. These findings support the hypothesis of nonrandomness of D group chromosomes involved in centric‐fusion translocation. The importance of the identification of Dgroup chromosomes involved in centriofusion translocation in relation to genetic counseling is discussed.
An X‐linked recessive variety of ichthyosis vulgaris different from the X‐linked ichthyosis of Wells and Kerr
Authors: Vibrans Ulrich , Altwein Jens E.
Published: June 2009

Pedigree analysis of ichthyosiz vulgaris in an extensive North German kindred revealed X‐linked recessive inheritance. Only males were affected; heterozygous females had no sign of this derma‐tosis. Clinically and histologically, the disease resembled the autosomal dominant form. The differential diagnosis between this X‐linked recessive ichthyosis vulgaris, ichthyosiz congenita mitis, and X‐linked ichthyosis of the Wells‐Kerr type is discussed. We conclude from our qtudy that ichthyosis vulgariz is genetically heterogeneous.
Non‐HLA T‐cell reactivity during the first year after HLA‐identical living‐related kidney transplantation
Authors: Gerrits Jeroen H. , Van De Wetering Jacqueline , Drabbels Jos J. , IJzermans Jan N.M. , Claas Frans H.J. , Weimar Willem , Van Besouw Nicole M.
Published: June 2009

Abstract:  Background:  It has been reported that donor‐reactive T‐cell responses may decrease during the first year after HLA‐mismatched organ transplantation. We wondered whether donor‐reactive T‐cell responses directed to minor histocompatibility antigens (mHAgs) or other non‐HLA antigens also decrease after HLA‐identical living‐related (LR) kidney transplantation.

Methods:  We studied donor‐reactive T‐cell responses by IFN‐γ and granzyme B (GrB) Elispot assays in 15 HLA‐identical LR kidney transplant recipients before, six months and one yr after transplantation. Third‐party reactivity was used as control. Patient and donor peripheral blood mononuclear cells were typed for 11 known mHAgs.

Results:  During the study period, 60% and 36% of the patients demonstrated donor‐reactive IFN‐γ and GrB producing cells (pc), respectively. The number of donor‐reactive IFN‐γ and GrB pc was significantly lower than the number of third‐party reactive IFN‐γ and GrB pc. After transplantation, donor‐reactivity and third‐party reactivity were comparable to pre‐transplant values. No relation was found in mHAg mismatches between donor and recipient and donor‐reactive T‐cell response.

Conclusions:  Donor‐reactivity could be detected before and after HLA‐identical LR kidney transplantation, but was not related with the number of mHAg mismatches, and did not decrease after transplantation.
Disparity in utilization of combined kidney–liver transplantation in the United States
Authors: Mehta S.D. , Leehey D.J.
Published: June 2009

Abstract:  Background:  Orthotopic liver transplantation (OLT) is performed as a definitive treatment of acute and chronic liver failure. The prevalence of acute and chronic kidney diseases is substantially higher in this population secondary to diverse etiologies. Combined kidney–liver transplantation (CKLT) is widely performed in some centers, even though there are no definitive studies which support or contradict this practice.

Methods:  We comprehensively reviewed OLT as well as CKLT data from US transplant centers provided by United Network of Organ Sharing (UNOS).

Results:  The incidence of CKLT as a percentage of total OLTs performed has been increasing, especially in the post‐MELD era (2002 and after). Moreover, there is a great disparity among centers in regard to percentage of CKLTs to total OLTs.

Conclusion:  We conclude that there is much difference of opinion among US transplant centers as to indications for CKLT. A more scientific approach to this problem including studies to assess the role of kidney biopsy in determining renal outcome after OLT is needed.
Prevalence and staging of chronic kidney disease in renal transplant recipients
Authors: Costa de Oliveira Cláudia Maria , Mota Márcia Uchoa , Mota Rosa Salani , Nóbrega Joana Oliveira , Melo Débora Silva , Vieira Ariane Sá , Fernandes Paula Frassinetti Castelo Branco , Campos Henry de Holanda , Evangelista João Batista
Published: June 2009

Abstract:  Introduction:  Diagnosis and staging of chronic kidney disease (CKD) is important for management and prevention of renal disease progression. It is unclear whether K/DOQI guidelines of the National Kidney Foundation are applicable to diagnosis of CKD in renal transplant recipients (RTRs) and which method is most appropriate for estimating glomerular filtration.

Objectives:  To determine the prevalence and staging of CKD in RTRs, according to K/DOQI guidelines, and the prevalence of complications of CKD.

Subjects and methods:  This cross‐sectional study included RTRs at least six months post‐transplantation followed at a single out‐patient service. The glomerular filtration rate (GFR) was estimated with two different equations: the MDRD equation (Modification of Diet in Renal Disease) with four variables (age, creatinine level, gender, and race) and the Cockcroft–Gault (CG) formula. Patients with GFR more than 60 mL/min/1.73 m2 were diagnosed with CKD only in the presence of renal damage (hematuria, proteinuria, or evidence of injury in renal biopsy). CKD staging was compared to the two equations and the prevalence of complications was determined.

Results:  The study evaluated 241 RTRs (average age: 40.6 ± 12.5 yr, 62.2% male; 4.5% black, 50.6% from cadaveric donors). Average follow‐up time was 6.8 ± 6.1 yr and the average baseline creatinine level was 1.48 ± 0.72 mg/dL. CKD was diagnosed in 70.5% of RTRs, of whom 52.9% (MDRD)/47.6% (CG) were classified as Stage III (GFR: 30–59 mL/min/1.73 m2). The agreement between the two methods was very close with regard to CKD diagnosis (κ = 0.92) and close for stage‐dependent prevalence (κ = 0.68). The prevalence of anemia, hypocalcemia, hyperphosphatemia (HF), hyperuricemia (HU), and systemic arterial hypertension (SAH) was 10.6%, 7.6%, 10.3%, 54%, and 73.4% for patients with CKD. Significant differences were observed for HU, HF and SAH in patients without CKD. Anemia, HU and SAH were associated with CKD stage (p < 0.001).

Conclusion:  The prevalence of CKD in the study population was high (70.5%). The two equations tested correlated closely when used for GFR estimation. Routine CKD staging in RTRs would provide patients with safer and more appropriate management.
Evasion and subversion of antigen presentation by Mycobacterium tuberculosis
Authors: Baena A. , Porcelli S. A.
Published: June 2009

Mycobacterium tuberculosis is one of the most successful of human pathogens and has acquired the ability to establish latent or progressive infection and persist even in the presence of a fully functioning immune system. The ability of M. tuberculosis to avoid immune‐mediated clearance is likely to reflect a highly evolved and coordinated program of immune evasion strategies, including some that interfere with antigen presentation to prevent or alter the quality of T‐cell responses. Here, we review an extensive array of published studies supporting the view that antigen presentation pathways are targeted at many points by pathogenic mycobacteria. These studies show the multiple potential mechanisms by which M. tuberculosis may actively inhibit, subvert or otherwise modulate antigen presentation by major histocompatibility complex class I, class II and CD1 molecules. Unraveling the mechanisms by which M. tuberculosis evades or modulates antigen presentation is of critical importance for the development of more effective new vaccines based on live attenuated mycobacterial strains.
Association of PTPN22 gene functional variants with development of pulmonary tuberculosis in Moroccan population
Authors: Lamsyah H. , Rueda B. , Baassi L. , Elaouad R. , Bottini N. , Sadki K. , Martin J.
Published: June 2009

Mycobacterium tuberculosis, the causal agent of pulmonary tuberculosis (TB), remains a major health problem throughout the world causing high mortality in humans. Previous studies showed that several genes may play crucial roles in susceptibility to TB. The PTPN22 gene encodes the lymphoid tyrosine phosphatase that has an important regulatory effect on T‐ and B‐cell activation in immune response. The purpose of this study was to investigate the role of two functional missense single nucleotide polymorphisms (SNPs) of the PTPN22 gene region (R620W and R263Q) in the susceptibility to TB in the Moroccan population. A case–control association study was performed including 123 pulmonary TB patients and 155 healthy controls. All subjects were genotyped by TaqMan SNP genotyping assays. Regarding the PTPN22 R620W (C1858T) SNP, we observed a statistically significant difference in the distribution of the PTPN22 1885T allele between pulmonary TB patients and healthy controls (0.41% vs 3.2%, P = 0.01, odds ratio (OR) = 0.14, 95% confidence interval (CI) = 0.01–0.93). With respect to the PTPN22 R263Q (G788A), we observed an increase of 788A allele frequencies in TB patients compared with those in healthy controls (3.65% vs 0.65%, P = 0.01, OR = 5.85, 95% CI = 1.17–39.55). These results suggest that PTPN22 gene variants may affect susceptibility to TB in the Moroccan population.
Heat stress‐induced limitations to reproductive success in Gossypium hirsutum
Authors: Snider John L. , Oosterhuis Derrick M. , Skulman Briggs W. , Kawakami Eduardo M.
Published: June 2009

Using in vitro systems, numerous authors have cited the sensitivity of pollen tube growth to high temperature as a major cause of low yields for crops with valuable reproductive structures. We investigated the hypothesis that in vivo fertilization efficiency would be negatively affected by heat stress‐induced changes in energy reserves and calcium‐mediated oxidative status in the pistil. Gossypium hirsutum plants exposed to optimal (30/20°C) or high day temperature (38/20°C) conditions during flowering were analyzed for fertilization efficiency via UV microscopic observation of pollen tube‐containing ovules and for soluble carbohydrates, adenosine triphosphate (ATP), calcium, antioxidant enzyme activity and NADPH oxidase (NOX; EC 1.6.3.1) activity in the pistil. Leaf measurements included gas exchange, chlorophyll content, quantum efficiency and ATP content of the subtending leaf on the day of anthesis. In the pistil fertilization efficiency, soluble carbohydrates, ATP content and NOX activity declined significantly, whereas water soluble calcium and glutathione reductase (EC 1.8.1.7) activity increased, and superoxide dismutase (EC 1.15.1.1) activity remained unchanged. In leaves, heat stress decreased photosynthesis, quantum efficiency and chlorophyll content, but increased stomatal conductance. We conclude that decreased source leaf activity either inhibits pollen development, tube growth through the style or guidance to the ovules as a result of an insufficient energy supply to the developing pistil. We further conclude that a calcium‐augmented antioxidant response in heat‐stressed pistils interferes with enzymatic superoxide production needed for normal pollen tube growth and fertilization of the ovule.
Natural killer T cell facilitated engraftment of rat skin but not islet xenografts in mice
Authors: Gordon Ethel J. , Kelkar Vinaya
Published: June 2009

Abstract:  Background:  We have studied cellular components required for xenograft survival mediated by anti‐CD154 monoclonal antibody (mAb) and a transfusion of donor spleen cells and found that the elimination of CD4+ but not CD8+ cells significantly improves graft survival. A contribution of other cellular components, such as natural killer (NK) cells and natural killer T (NKT) cells, for costimulation blockade‐induced xenograft survival has not been clearly defined. We therefore tested the hypothesis that NK or NKT cells would promote rat islet and skin xenograft acceptance in mice.

Methods:  Lewis rat islets or skin was transplanted into wild type B6 mice or into B6 mice that were Jα18null, CD1null, or beta2 microglobulin (β2M)null NK 1.1 depleted, or perforinnull. Graft recipients were pretreated with an infusion of donor derived spleen cells and a brief course of anti‐CD154 mAb treatments. Additional groups received mAb or cells only.

Results:  We first observed that the depletion of NK1.1 cells does not significantly interfere with graft survival in C57BL/6 (B6) mice. We used NKT cell deficient B6 mice to test the hypothesis that NKT cells are involved in islet and skin xenograft survival in our model. These mice bear a null mutation in the gene for the Jα18 component of the T‐cell receptor. The component is uniquely associated with NKT cells. We found no difference in islet xenograft survival between Jα18null and wild type B6 mice. In contrast, median skin graft survival appeared shorter in Jα18null recipients. These data imply a role for Jα18+ NKT cells in skin xenograft survival in treated mice. In order to confirm this inference, we tested skin xenograft survival in B6 CD1null mice because NKT cells are CD1 restricted. Results of these trials demonstrate that the absence of CD1+ cells adversely affects rat skin graft survival. An additional assay in β2Mnull mice demonstrated a requirement for major histocompatibility complex (MHC) class I expression in the graft host, and we demonstrate that CD1 is the requisite MHC component. We further demonstrated that, unlike reports for allograft survival, skin xenograft survival does not require perforin‐secreting NK cells.

Conclusions:  We conclude that MHC class I+ CD1+ Jα18+ NKT cells promote the survival of rat skin but not rat islet xenografts. These studies implicate different mechanisms for inducing and maintaining islet vs. skin xenograft survival in mice treated with donor antigen and anti‐CD154 mAb, and further indicate a role for NKT cells but not NK cells in skin xenograft survival.
Quantitative tools for assessing the fate of xenotransplanted human stem/progenitor cells in chimeric mice
Authors: Cheng Kang , Gupta Sanjeev
Published: June 2009

Abstract:  Background:  Identification of transplanted human cells in mouse models is important for studying the biology and therapeutic potential of stem/progenitor cells. As stem/progenitor cells are often transplanted in low numbers, detection of cell engraftment requires sensitive tools. Probes for single copy genes, as well as repetitive genetic elements are available for detecting transplanted cells, although their value relative to one another had not been defined.

Methods:  We examined whether human sequences in chimeric mice could be measured with quantitative real‐time polymerase chain reactions for Charcot‐Marie‐Tooth disease, type 1 repeat element, sex‐determining region Y, or short tandem repeats (STR) across human leukocyte antigen (HLA) regions, which are distinct from rodent genomes.

Results:  We found that specific probes for all three candidate approaches successfully identified human cells in mixtures containing human and mouse genomes. However, probes for Charcot‐Marie‐Tooth disease element or STRs for HLA regions were less effective for low numbers of transplanted human stem/progenitor cells in mice than human sex‐determining region on Y‐chromosome. None of the approaches could identify transplanted human cells constituting less than one percent of the total cell mass. This required localization of transplanted cells in tissue sections with human‐specific in situ hybridization probes.

Conclusions:  Quantitative assays with probes for single copy gene sequences, STRs or sex‐determining region will be helpful for demonstrating organ repopulation, although initial lower frequency engraftment of human cells in chimeric mice will be most effectively identified by complementary tools, such as in situ localization of human cells in tissues.
Primary antimicrobial resistance of Helicobacter pylori in children during the past 9 years
Authors: Kato Seiichi , Fujimura Shigeru
Published: June 2009

Background:  Antimicrobial resistance of Helicobacter pylori is a growing problem in clinical practice, particularly clarithromycin resistance. The aim of the present study was therefore to investigate the prevalence of H. pylori resistance to antimicrobial agents in Japanese children.

Methods:  A total of 61 H. pylori strains isolated from children (mean age, 12.6 years; range, 4–18 years) between 1999 and 2007 were studied for primary antimicrobial resistance, using a microdilution method. In addition, the eradication rate with lansoprazole‐based triple regimens was determined.

Results:  The overall resistance rate of clarithromycin, amoxicillin and metronidazole was 36.1%, 0% and 14.8%, respectively. Resistance to both clarithromycin and metronidazole was detected in 6.6% of the strains. The rate of clarithromycin‐resistant strains was 32.4% from 1999 to 2002 and 40.7% from 2003 to 2007, and clarithromycin minimum inhibitory concentration at which 90% of the isolates were inhibited (MIC90) increased fourfold from 1999–2002 to 2003–2007, with all clarithromycin‐resistant strains showing low‐level resistance. Metronidazole resistance rates were not different between these two study periods. Regimens involving amoxicillin and clarithromycin (n= 49) had a higher eradication rate in clarithromycin‐susceptible strains (97.1%) than in the resistant strains (57.1%; P < 0.001). There was no difference in the eradication rate between 7 day and 10 or 14 day courses of the regimens (P= 0.53). The regimen with amoxicillin and metronidazole produced successful eradication in all nine patients with clarithromycin‐resistant strains.

Conclusions:  Clarithromycin resistance of H. pylori is high, and triple regimen treatment containing clarithromycin should be decided based on susceptibility to the agent.
Pediatric transtracheal and cricothyrotomy airway devices for emergency use: which are appropriate for infants and children?
Authors: COTÉ CHARLES J. , HARTNICK CHRISTOPHER J.
Published: June 2009

Cricothyrotomy or insertion of a transtracheal device is a life‐saving maneuver that may be performed on an emergent or semi‐elective basis as a means of bypassing an obstructed upper airway. A surgeon is trained to perform this life‐saving procedure whereas most anesthesiologists are not facile with the scalpel. It is for this reason that many percutaneous devices have been developed for use by surgeons and nonsurgeons alike. Unfortunately, the majority of such devices are designed for use in adults and/or teenagers but are not appropriate for neonates and infants. The unique anatomy of the infant larynx, the small size of the cricothyroid membrane, and the technical difficulty of locating the correct anatomical structures make the use of most of these devices impractical if not outright dangerous in neonates and infants. This paper will review many (but not all) of the available devices, associated literature, pitfalls and dangers. It is emphasized that each clinician should become familiar with the advantages and disadvantages of these devices and obtain training with simulators or animal models. A strategy for management of the ‘cannot ventilate, cannot oxygenate, cannot intubate’ situation should be developed with age and size appropriate equipment.
Infections of the airway
Authors: JENKINS IAN A. , SAUNDERS MICHAEL
Published: June 2009

Infections of the airway in children may present to the anesthetist as an emergency in several locations: the Emergency Department, the Operating Department or on Intensive Care. In all of these locations, relevant and up to date knowledge of presentations, diagnoses, potential complications and clinical management will help the anesthetist and the surgical team, not only with the performance of their interventions, but also in buying time before these are undertaken, avoiding complications and altering the eventual outcome for the child. Diseases such as epiglottitis and diphtheria may show diminished incidence but they have not gone away and their clinical features and essential management remain unchanged. Paradoxically, perhaps, some conditions such as Lemierre’s syndrome appear to be making a comeback. In these instances, clinicians need to be alert to these less common conditions, not only in regard to the disease itself but also to potentially serious complications. This article describes those infections of the airway that are most likely to present to the anesthetist, their attendant complications and recommendations for treatment.
Iatrogenic damage to the pediatric airway Mechanisms and scar development
Authors: HOLZKI JOSEF , LASCHAT MICHAEL , PUDER CHRISTIAN
Published: June 2009

Iatrogenic damage to the pediatric airway occurs rather often. Most injuries will heal without any sequelae because larynx and trachea of children tolerate considerable trauma. However, sometimes the injury is penetrating the mucosa and scar formation can lead to an obstruction of the airway which is followed by a tracheostomy and long term surgery. A great problem is the early detection of trauma since noisy breathing develops often late when scar formation has occluded more than 50% of the airway. A selection of photo documents of airway endoscopy out of more than 5000 photos from the years 1987–2007 were used to explain the development of injuries from minor lesions to large areas of necrosis of the mucosa of larynx and trachea of infants and children. The visualization of airway lesions might help to prevent iatrogenic damage.
Key targets of hormonal treatment of prostate cancer. Part 1: the androgen receptor and steroidogenic pathways
Authors: Vis André N. , Schröder Fritz H.
Published: June 2009

OBJECTIVE

Knowledge of the molecular and cellular changes that occur during the transition of hormone‐naïve to castration‐resistant prostate cancer (CRPC) is increasing rapidly. This might provide a window of opportunity for (future) drug development, and for treating patients with these potential devastating states of disease. The objective of this review is to provide an understanding of the mechanisms that prostate cancer cells use to bypass androgen‐deprived conditions.

METHODS

We searched PubMed for experimental and clinical studies that describe the molecular changes that lead to CRPC.

RESULTS

CRPC remains dependent on a functional androgen receptor (AR), AR‐mediated processes, and on the availability of intraprostatic intracellular androgens. CRPCs might acquire different (molecular) mechanisms that enable them to use intracellular androgens more efficiently (AR amplification, AR protein overexpression, AR hypersensitivity), use alternative splice variants of the AR protein to mediate androgen‐independent AR functioning, and have altered co‐activator and co‐repressor gene and protein expression. Furthermore, CRPCs might have the ability to synthesise androgens de novo from available precursors through a renewed and up‐regulated synthesis of steroid‐hormone converting enzymes. Blocking of enzymes key to de novo androgen synthesis could be an alternative means to treat patients with advanced and/or metastatic disease.

CONCLUSION

In CRPC, prostate cancer cells still rely on intracellular androgens and on an active AR for growth and survival. CRPCs have gained mechanisms that enable them to use steroids from the circulation more efficiently through altered gene expression, and through a renewed and up‐regulated synthesis of steroid hormone‐converting enzymes. Additionally, CRPCs might synthesise AR isoforms that enable AR mediated processes independent from available androgens.
Dynamic GIS Case Studies: Wildfire Evacuation and Volunteered Geographic Information
Authors: Pultar Edward , Raubal Martin , Cova Thomas J , Goodchild Michael F
Published: June 2009

Incorporating the temporal element into traditional GIS is a challenge that has been researched for many years and has many proposed solutions. The implemented system “Extended Dynamic GIS” or EDGIS is based on the “geo‐atom” and Space Time Point (STP). EDGIS provides a platform for spatiotemporal data representation, storage, and query in order to address the need for a dynamic GIS to manage complex geographic data types. The system has the capability of executing spatiotemporal object interaction queries (OIQs) such as crossing and coincidence of field‐objects and object‐fields. In this article existing dynamic GIS analysis techniques are further improved and enhanced through exploration of more in‐depth case studies. Further examined here are applications to wildfire evacuation modeling and travel scenarios of urban environments with individuals providing volunteered geographic information (VGI). The EDGIS platform provides a means for interacting with a range of dynamic geographic phenomena. The areas of transportation, location based services (LBS), hazards, and geo‐sensor networks provide challenges intertwined with the above applications as well as additional challenges pertinent to the ongoing GIScience research topic of spatiotemporal GIS. Using EDGIS to explore the described case studies of wildfire evacuation as well as VGI provides the advancements described above and demonstrates implemented uses for dynamic GIS.
gvSOS: A New Client for the OGC® Sensor Observation Service Interface Standard
Authors: Tamayo Alain , Huerta Joaquín , Granell Carlos , Díaz Laura , Quirós Ricardo
Published: June 2009

A key problem with sensor networks is achieving interoperability between different networks potentially built using different software and hardware platforms. Services interfaced by the Open Geospatial Consortium (OGC) specifications allow GIS clients to access geospatial data without knowing the details about how these data are gathered or stored. Currently, OGC is working on a set of interoperable interfaces and metadata encodings known as Sensor Web Enablement (SWE) that enables the integration of heterogeneous sensor systems and measurements into geospatial information infrastructures. In this article we present the implementation of gvSOS, a new module for gvSIG to connect to Sensor Observation Services (SOS). The gvSOS client module allows gvSIG users to interact with SOS servers, displaying the information gathered by sensors as a layer composed by features. We present the software engineering development process followed to build the module. For each step of the process we specify the main obstacles found during the development such as restrictions of the gvSIG architecture, inaccuracies in the OGC specifications, and a set of common problems found in current SOS server implementations available on the Internet. For most of the problems found we propose a solution, or at least we present a path that might lead to it.
Typography for children may be inappropriately designed
Authors: Wilkins Arnold , Cleave Roanna , Grayson Nicola , Wilson Louise
Published: June 2009

We present four studies indicating that the size and design of the typeface in textual material for children aged 7–9 may impair speed of reading and comprehension, and measurement of reading attainment. The first study compared the speed with which sample sentences were comprehended. The sentences were printed in Arial font with an x‐height of 4.2 or 5.0 mm. The sentences were verified 9% more quickly when presented in the larger typeface. The second study compared reading age on the Salford Sentence Reading Test when the typeface remained at the initial size (x‐height 3.3 mm) throughout the test, and when it decreased in size as usual. The average reading age measured with the larger font was 4 months older. The final studies compared the font Sassoon Primary with the font Verdana and showed that Verdana was read and searched more quickly.
PRICING CORPORATE SECURITIES UNDER NOISY ASSET INFORMATION
Authors: Frey Rüdiger , Schmidt Thorsten
Published: June 2009

This paper considers the pricing of corporate securities of a given firm, in particular equity, when investors do not have full information on the firm's asset value. We show that under noisy asset information, the pricing of corporate securities leads to a nonlinear filtering problem. This problem is solved by a Markov chain approximation, leading to an efficient finite‐dimensional approximative filter for the asset value. We discuss several applications and illustrate our results with a simulation study.
CREDIT SPREADS, OPTIMAL CAPITAL STRUCTURE, AND IMPLIED VOLATILITY WITH ENDOGENOUS DEFAULT AND JUMP RISK
Authors: Chen Nan , Kou S. G.
Published: June 2009

We propose a two‐sided jump model for credit risk by extending the Leland–Toft endogenous default model based on the geometric Brownian motion. The model shows that jump risk and endogenous default can have significant impacts on credit spreads, optimal capital structure, and implied volatility of equity options: (1) Jumps and endogenous default can produce a variety of non‐zero credit spreads, including upward, humped, and downward shapes; interesting enough, the model can even produce, consistent with empirical findings, upward credit spreads for speculative grade bonds. (2) The jump risk leads to much lower optimal debt/equity ratio; in fact, with jump risk, highly risky firms tend to have very little debt. (3) The two‐sided jumps lead to a variety of shapes for the implied volatility of equity options, even for long maturity options; although in general credit spreads and implied volatility tend to move in the same direction under exogenous default models, this may not be true in presence of endogenous default and jumps. Pricing formulae of credit default swaps and equity default swaps are also given. In terms of mathematical contribution, we give a proof of a version of the “smooth fitting” principle under the jump model, justifying a conjecture first suggested by Leland and Toft under the Brownian model.
PORTFOLIO SELECTION WITH MONOTONE MEAN‐VARIANCE PREFERENCES
Authors: Maccheroni Fabio , Marinacci Massimo , Rustichini Aldo , Taboga Marco
Published: June 2009

We propose a portfolio selection model based on a class of monotone preferences that coincide with mean‐variance preferences on their domain of monotonicity, but differ where mean‐variance preferences fail to be monotone and are therefore not economically meaningful. The functional associated with this new class of preferences is the best approximation of the mean‐variance functional among those which are monotonic. We solve the portfolio selection problem and we derive a monotone version of the capital asset pricing model (CAPM), which has two main features: (i) it is, unlike the standard CAPM model, arbitrage free, (ii) it has empirically testable CAPM‐like relations. The monotone CAPM has thus a sounder theoretical foundation than the standard CAPM and a comparable empirical tractability.
MAXIMIZING THE GROWTH RATE UNDER RISK CONSTRAINTS
Authors: Pirvu Traian A. , Žitković Gordan
Published: June 2009

We investigate the ergodic problem of growth‐rate maximization under a class of risk constraints in the context of incomplete, Itô‐process models of financial markets with random ergodic coefficients. Including value‐at‐risk, tail‐value‐at‐risk, and limited expected loss, these constraints can be both wealth‐dependent (relative) and wealth‐independent (absolute). The optimal policy is shown to exist in an appropriate admissibility class, and can be obtained explicitly by uniform, state‐dependent scaling down of the unconstrained (Merton) optimal portfolio. This implies that the risk‐constrained wealth‐growth optimizer locally behaves like a constant relative risk aversion (CRRA) investor, with the relative risk‐aversion coefficient depending on the current values of the market coefficients.
Continua of specificity and virulence in plant host–pathogen interactions: causes and consequences
Authors: Barrett Luke G. , Kniskern Joel M. , Bodenhausen Natacha , Zhang Wen , Bergelson Joy
Published: June 2009

Ecological, evolutionary and molecular models of interactions between plant hosts and microbial pathogens are largely based around a concept of tightly coupled interactions between species pairs. However, highly pathogenic and obligate associations between host and pathogen species represent only a fraction of the diversity encountered in natural and managed systems. Instead, many pathogens can infect a wide range of hosts, and most hosts are exposed to more than one pathogen species, often simultaneously. Furthermore, outcomes of pathogen infection vary widely because host plants vary in resistance and tolerance to infection, while pathogens are also variable in their ability to grow on or within hosts. Environmental heterogeneity further increases the potential for variation in plant host–pathogen interactions by influencing the degree and fitness consequences of infection. Here, we describe these continua of specificity and virulence inherent within plant host–pathogen interactions. Using this framework, we describe and contrast the genetic and environmental mechanisms that underlie this variation, outline consequences for epidemiology and community structure, explore likely ecological and evolutionary drivers, and highlight several key areas for future research.

Contents

Summary
513

I.
Introduction
513

II.
Continua in plant host–pathogen interactions
514

III.
Mechanisms underlying continua in specificity and virulence
516

IV.
Ecological consequences
519

V.
Evolutionary patterns and processes
520

VI.
Conclusions
524

Acknowledgements
525

References
525
Segregation of temporal and spatial distribution between kleptoparasites and parasitoids of the eusocial sweat bee, Lasioglossum malachurum (Hymenoptera: Halictidae, Mutillidae)
Authors: POLIDORI Carlo , BORRUSO Luigimaria , BOESI Roberto , ANDRIETTI Francesco
Published: June 2009

Cuckoo bees and velvet ants use different resources of their shared host bees, the former laying eggs on the host pollen stores and the latter on immature stages. We studied the activity patterns of the cuckoo bee Sphecodes monilicornis and the velvet ant Myrmilla capitata at two nesting sites of their host, the social digger bee Lasioglossum malachurum, over a 3 year period. Due to the difference in host exploitation, we expected different temporal patterns of the two natural enemies as well as a positive spatial association with host nest density for both species. At a daily level, S. monilicornis was more abundant between 10.00 and 15.00 h, while M. capitata was most active in the early morning and late afternoon; both species activities were independent from host provisioning activity. The activity of cuckoo bees was in general positively correlated with the density of open host nests (but not with the total number of nests), while that of velvet ants was rarely correlated with this factor. Sphecodes monilicornis was seen both attacking the guard bees and directly entering into the host nests or digging close to nest entrances, while M. capitata only gained access to host nests through digging. We conclude that the temporal and spatial segregation between the two species may be, at least partially, explained both by the different resources exploited and by the different dynamics of host interactions.
Vulnerability of larvae of two species of aphidophagous ladybirds, Adalia bipunctata Linnaeus and Harmonia axyridis Pallas, to cannibalism and intraguild predation
Authors: SATO Satoru , YASUDA Hironori , EVANS Edward W. , DIXON Anthony F. G.
Published: June 2009

Vulnerability of larvae of two species of aphidophagous ladybirds, Adalia bipunctata Linnaeus and Harmonia axyridis Pallas, to cannibalism and intraguild predation was assessed in the laboratory. In the first experiment, a first instar of one of the two above species was kept with a fourth instar of the other species in a Petri dish. The number of times each first instar larva was encountered by the fourth instar larva and the fate of the first instar was determined over a period of 10 min. The fourth instar larvae captured and killed all the first instar larvae of their own species at the first encounter. However, when presented with fourth instar larvae of the other species the first instar larvae of A. bipunctata and H. axyridis were encountered 6.4 ± 1.3 (n = 10) and 19.4 ± 2.1 (n = 10), respectively. In this experiment no first instar larvae of H. axyridis, whereas all those of A. bipunctata, were killed.
Mating behavior and genital damage during copulation in the leaf beetle Lema coronata (Chrysomelidae: Criocerinae)
Authors: MATSUMURA Yoko , AKIMOTO Shin‐ichi
Published: June 2009

The criocerine leaf beetle Lema coronata Baly has extremely long genitalia that reach more than twice the body length in both sexes. We observed mating behavior of this species in the laboratory and inspected the male genital morphology using a scanning electron microscope. The males did not perform pre‐copulatory courtship and post‐copulatory guarding of the mates, and copulation lasted only for about 30 min. The surface of male genitalia is smooth without any special structures at the tip. A fragment of broken male genitalia was detected in the spermathecal duct of one female. We discuss the adaptive significance of male genital damage and the selective factor of elongated genitalia.
Influence of soil moisture on supercooling capacity and associated physiological parameters of overwintering larvae of rice stem borer
Authors: HOU Maolin , HAN Yongqiang , LIN Wei
Published: June 2009

Influence of soil moisture on the supercooling capacity and associated physiological parameters of overwintering larvae of the rice stem borer Chilo suppressalis was examined by exposing larvae to soil moistures of 25, 50, 75 and 100% of saturated soil water content (SSWC) at ambient temperature for 30 d from December 2007 to January 2008 in Beijing, China. At the end of the exposure, supercooling points (SCPs) varied significantly among the treatments, the lowest being in the larvae exposed to soil moisture of 25% SSWC. Fresh weight was significantly higher in the larvae exposed to soil moisture of 100% SSWC than in those kept at 25 and 50% SSWC. Dry weight and body water content (% fresh weight) were not different among the treatments. Glucose and trehalose contents were markedly lower, and glycerol content was significantly higher in the larvae confined to soil moisture of 25% SSWC than in those exposed to the other soil moisture treatments. It is suggested that variation in body water content (% fresh weight) contributes to the differences in SCPs of the overwintering C. suppressalis larvae in all treatments, but the influence of soil moisture treatments on supercooling capacity are caused through changes in glycerol content.
Zircon U–Pb age, trace element and Hf isotope composition of Kongling terrane in the Yangtze Craton: refining the timing of Palaeoproterozoic high‐grade metamorphism
Authors: WU Y.‐B. , GAO S. , GONG H.‐J. , XIANG H. , JIAO W.‐F. , YANG S.‐H. , LIU Y.‐S. , YUAN H.‐L.
Published: June 2009

U–Pb age, trace element and Hf isotope compositions of zircon were analysed for a metasedimentary rock and two amphibolites from the Kongling terrane in the northern part of the Yangtze Craton. The zircon shows distinct morphological and chemical characteristics. Most zircon in an amphibolite shows oscillatory zoning, high Th/U and 176Lu/177Hf ratios, high formation temperature, high trace element contents, clear negative Eu anomaly, as well as HREE‐enriched patterns, suggesting that it is igneous. The zircon yields a weighted mean 207Pb/206Pb age of 2857 ± 8 Ma, representing the age of the magmatic protolith. The zircon in the other two samples is metamorphic. It has low Th/U ratios, low trace element concentrations, variable HREE contents (33.8 ≥ LuN≥2213; 14.7 ≤ LuN/SmN ≤ 354) and 176Lu/177Hf ratios (0.000030–0.001168). The data indicate that the zircon formed in the presence of garnet and under upper amphibolite facies conditions. The metamorphic zircon yields a weighted mean 207Pb/206Pb age of 2010 ± 13 Ma. These results combined with previously obtained Palaeoproterozoic metamorphic ages suggest a c. 2.0 Ga Palaeoproterozoic collisional event in the Yangtze Craton, which may result from the assembly of the supercontinent Columbia. The zircon in two samples yields weighted mean two‐stage Hf model (TDM2) ages of 3217 ± 110 and 2943 ± 50 Ma, respectively, indicating that their protoliths were mainly derived from Archean crust.
Hemiconvulsion–hemiplegia syndrome in a patient with severe myoclonic epilepsy in infancy
Authors: Sakakibara Takafumi , Nakagawa Eiji , Saito Yoshiaki , Sakuma Hiroshi , Komaki Hirofumi , Sugai Kenji , Sasaki Masayuki , Kurahashi Hirokazu , Hirose Shinichi
Published: June 2009

We report a 2‐year‐old girl who had repeated febrile or afebrile seizures since infancy. Prolonged left/right hemiconvulsions and myoclonus of the eyelids/extremities with generalization to tonic–clonic seizures, were refractory to antiepileptic agents. At age 1 year and 4 months, she contracted rotavirus infection, and developed status epilepticus with persistent right hemiclonic seizures. Left unilateral brain edema with subsequent emergence of cortical laminar necrosis and white matter lesions, and progressive atrophy of the left cerebral hemisphere were noted during this period. She showed residual right hemiparesis and mild intellectual disability, and had generalized/eyelid myoclonia and hot water epilepsy after a 5‐month seizure‐free period. Analysis for SCN1A, the gene encoding the neuronal voltage‐gated Na+ channel α1 subunit revealed a nonsense mutation, R1892X. These indicate the potential risk in patients with severe myoclonic epilepsy in infancy (SMEI) to develop hemiconvulsion–hemiplegia (HH) syndrome. SCN1A mutations may need to be further explored in patients with HH syndrome without features of SMEI.
Game Theory and Risk Analysis
Authors: Cox, Jr. Louis Anthony (Tony)
Published: June 2009

Risk analysts often analyze adversarial risks from terrorists or other intelligent attackers without mentioning game theory. Why? One reason is that many adversarial situations—those that can be represented as attacker‐defender games, in which the defender first chooses an allocation of defensive resources to protect potential targets, and the attacker, knowing what the defender has done, then decides which targets to attack—can be modeled and analyzed successfully without using most of the concepts and terminology of game theory. However, risk analysis and game theory are also deeply complementary. Game‐theoretic analyses of conflicts require modeling the probable consequences of each choice of strategies by the players and assessing the expected utilities of these probable consequences. Decision and risk analysis methods are well suited to accomplish these tasks. Conversely, game‐theoretic formulations of attack‐defense conflicts (and other adversarial risks) can greatly improve upon some current risk analyses that attempt to model attacker decisions as random variables or uncertain attributes of targets (“threats”) and that seek to elicit their values from the defender's own experts. Game theory models that clarify the nature of the interacting decisions made by attackers and defenders and that distinguish clearly between strategic choices (decision nodes in a game tree) and random variables (chance nodes, not controlled by either attacker or defender) can produce more sensible and effective risk management recommendations for allocating defensive resources than current risk scoring models. Thus, risk analysis and game theory are (or should be) mutually reinforcing.
Comparison of Cooled‐Tip Versus 4‐mm‐Tip Catheter in the Efficacy of Acute Ablative Tissue Injury During Circumferential Pulmonary Vein Isolation
Authors: CHANG SHIH‐LIN , TAI CHING‐TAI , LIN YENN‐JIANG , LO LI‐WEI , TUAN TA‐CHUAN , UDYAVAR AMEYA R. , HU YU‐FENG , TSAO HSUAN‐MING , CHANG CHIEN‐JUN , TSAI WEN‐CHIN , CHEN SHIH‐ANN
Published: June 2009

Introduction:
Although several studies have reported the benefits of cooled‐tip ablation for circumferential pulmonary veins isolation (CPVI), the acute change of substrate property and acute PV reconnection have not been well demonstrated. The aim of this study was to compare the cooled‐tip with regular 4‐mm‐tip catheter in acute substrate change after CPVI and long‐term efficacy.

Methods and Results:
One hundred and fifty‐six patients (115 males, age 53 ± 12 years) who underwent CPVI for treatment of atrial fibrillation (AF) were included. Group A consisted of 52 patients with cooled‐tip ablation, and group B consisted of 104 patients with 4‐mm‐tip catheter ablation. The bipolar voltage of circumferential lesions was obtained using a 3‐dimensional (3D) mapping system (NavX) before and after CPVI. The electrical reconnections of 4 PVs were evaluated 30 minutes after CPVI using a circular catheter. Cooled‐tip catheter caused more reduction of the electrical voltage in PV antrum, lower incidence of acute PV reconnection, inducibility of AF, and gap‐related atrial tachyarrhythmia (AT). Less number of left atrial (LA) ablation line and ablation applications and less procedure time were found in cooled‐tip group compared to 4‐mm‐tip group. No significant difference in the incidence of pain sensation and complication was observed between the 2 groups. At a 14‐month follow‐up, the recurrence rate in the cooled‐tip group was lower than in the 4‐mm group (13.5% vs 33.7%, P = 0.009).

Conclusion:
Cooled‐tip catheter has a superior long‐term outcome than the 4‐mm‐tip catheter in CPVI, which may be associated with the efficacy of transmural block and electrical isolation in PV antrum.
A Review on the Sintering and Microstructure Development of Transparent Spinel (MgAl2O4)
Authors: Reimanis Ivar , Kleebe Hans‐Joachim
Published: June 2009

A review of the densification mechanisms and the microstructural development for transparent spinel made by free sintering and by hot pressing is given. The paper is divided into two main parts. The first part considers spinel without any sintering additives because there still is some controversy concerning the role of cation stoichiometry on sintering and grain growth. The second part discusses the role of the classic sintering aid, LiF, in processing transparent spinel. LiF is shown to have multiple behaviors: (1) it initially wets spinel and forms a liquid phase at relatively low temperatures, which affects early‐stage densification and also grain growth; (2) upon cooling from intermediate temperatures, or even from higher temperatures if microstructure evolution (e.g., formation of closed porosity) prevents volatization, the LiF‐containing liquid dewets and resides in isolated pockets; (3) LiF alters the cation stoichiometry, thereby enhancing diffusion via an increase in the concentration of oxygen vacancies; this affects both the densification rate and grain growth; and (4) it reacts with impurities in the system, thereby acting as a cleanser. For the production oftransparentspinel, it is critical that LiF or associated reaction products not be retained as a secondary phase.