bluuebunny/crossref_metadata_2025 huggingface dataset:
TEMPORAL AND SPATIAL COMPRESSION OF DYNAMIC POSITRON EMISSION TOMOGRAPHY IN SINOGRAM DOMAIN
Authors: CHEN ZHE , FENG DAVID DAGAN , CAI WEIDONG
Published: November 2005

A new algorithm for the compression of dynamic positron emission tomography (PET) data in sinogram domain is presented. It consists of a temporal compression stage based on the application of principal component analysis directly to the PET sinograms to reduce the dimensionality of the data. This is followed by a spatial compression stage using JPEG2000 to each principal component (PC) channel weighted by the signal in each channel. By combing these temporal and spatial compression techniques we can achieve a compression ratio as high as 129:1 while simultaneously reducing noise and improving functional estimation compared with the uncompressed data, and preserving the sinogram data for later analysis. We validate our approach with a simulated phantom 18F-fluoro-deoxyglucose (FDG) brain study and clinical dynamic PET datasets. The results of performance evaluation suggest the new compression technique not only is able to reduce the original sinogram datasets by more than 95%, but also improve the reconstructed image quality for the quantitative analysis.
OVERCOMING DRESS EFFECT IN EIGENSPACE
Authors: RAHMAN M. MASUDUR , ISHIKAWA SEIJI
Published: November 2005

This paper addresses a problem, due to human wearing clothes, in an appearance-based eigenspace technique called a dress effect in case of recognizing human postures. The dress effect in the eigenspace arises when a man/woman wears different texture-dress between training and testing stages. This study investigates that change of dresses creates the cloth's oriented eigenspace and it affects the robustness of an eigenspace technique. The dress effect is investigated in this paper employing various dress environments and image pre-processing by Sobel-edge filter is proposed in this paper for overcoming this problem. The application of Sobel-edge images over training and testing images creates an almost similar eigenspace of different models/persons, even changing the clothes. Promising obtained results are shown in terms of a numerical analysis, with a graphical representation of various eigenspaces and recognition rates in the performed experiments.
Prothrombotic Mutations, Hormone Therapy, and Venous Thromboembolism Among Postmenopausal Women
Authors: Straczek Céline , Oger Emmanuel , Yon de Jonage-Canonico Marianne Beau , Plu-Bureau Geneviève , Conard Jacqueline , Meyer Guy , Alhenc-Gelas Martine , Lévesque Hervé , Trillot Nathalie , Barrellier Marie-Thérèse , Wahl Denis , Emmerich Joseph , Scarabin Pierre-Yves
Published: November 2005

Background—

Oral estrogen increases the risk of venous thromboembolism (VTE) in postmenopausal women, particularly in those with a prothrombotic mutation. Transdermal estrogen may be safe with respect to VTE. We investigated the impact of the route of estrogen administration on the association between a prothrombotic mutation (factor V Leiden or prothrombin G20210A mutation) and VTE risk.

Methods and Results—

We performed a multicenter case-control study of VTE among postmenopausal women who were enrolled in 1999 through 2004 at 7 clinical centers in France. We recruited 235 consecutive patients with a first documented episode of idiopathic VTE and 554 controls. Factor V Leiden was associated with a 3.4-fold–increased risk of VTE (95% confidence interval [CI], 2.0 to 5.8), and a prothrombin mutation was associated with a 4.8-fold–increased risk of VTE (95% CI, 2.5 to 9.4). Oral but not transdermal estrogen was associated with an increased risk of VTE (odds ratio [OR], 4.3; 95% CI, 2.6 to 7.2; and OR, 1.2; 95% CI, 0.8 to 1.7, respectively). After adjustment for potential confounding factors, the combination of either factor V Leiden or prothrombin G20210A mutation and oral estrogen gave a 25-fold–increased risk of VTE compared with nonusers without mutation (95% CI, 6.9 to 95.0). However, the risk for women with prothrombotic mutation using transdermal estrogen was similar to that of women with a mutation who were not using estrogen (OR, 4.4; 95% CI, 2.0 to 9.9; and OR, 4.1; 95% CI, 2.3 to 7.4, respectively).

Conclusions—

In contrast to oral estrogen, transdermal estrogen does not confer additional risk on women who carry a prothrombotic mutation. The safety of transdermal estrogen has to be confirmed in randomized trials.
Estimating Cloud Optical Depth from Surface Radiometric Observations: Sensitivity to Instrument Noise and Aerosol Contamination
Authors: Beaulne Alain , Barker Howard W. , Blanchet Jean-Pierre
Published: November 2005

The spectral-difference algorithm of Barker and Marshak for inferring optical depth τ of broken clouds has been shown numerically to be potentially useful. Their method estimates cloud-base reflectance and τ using spectral radiometric measurements made at the surface at two judiciously chosen wavelengths. Here it is subject to sensitivity tests that address the impacts of two ubiquitous sources of potential error: instrument noise and presence of aerosol. Experiments are conducted using a Monte Carlo photon transport model, cloud-resolving model data, and surface albedo data from satellite observations. The objective is to analyze the consistency between inherent and retrieved values of τ. Increasing instrument noise, especially if uncorrelated at both wavelengths, decreases retrieved cloud fraction and increases retrieved mean τ. As with all methods that seek to infer τ using passive radiometry, the presence of aerosol requires that threshold values be set in order to discriminate between cloudy and cloud-free columns. A technique for estimating thresholds for cloudy columns is discussed and demonstrated. Finally, it was found that surface type and mean inherent τ play major roles in defining retrieval accuracy.
Radiative Effects of Cloud Horizontal Inhomogeneity and Vertical Overlap Identified from a Monthlong Cloud-Resolving Model Simulation
Authors: Wu Xiaoqing , Liang Xin-Zhong
Published: November 2005

The representation of subgrid horizontal and vertical variability of clouds in radiation schemes remains a major challenge for general circulation models (GCMs) due to the lack of cloud-scale observations and incomplete physical understanding. The development of cloud-resolving models (CRMs) in the last decade provides a unique opportunity to make progress in this area of research. This paper extends the study of Wu and Moncrieff to quantify separately the impacts of cloud horizontal inhomogeneity (optical property) and vertical overlap (geometry) on the domain-averaged shortwave and longwave radiative fluxes at the top of the atmosphere and the surface, and the radiative heating profiles. The diagnostic radiation calculations using the monthlong CRM-simulated tropical cloud optical properties and cloud fraction show that both horizontal inhomogeneity and vertical overlap of clouds are equally important for obtaining accurate radiative fluxes and heating rates. This study illustrates an objective approach to use long-term CRM simulations to separate cloud overlap and inhomogeneity effects, based on which GCM representation (such as mosaic treatment) of subgrid cloud–radiation interactions can be evaluated and improved.
Influences of Asymmetric Heating on Hurricane Evolution in the MM5
Authors: Möller J. Dominique , Shapiro Lloyd J.
Published: November 2005

While previous idealized studies have demonstrated the importance of asymmetric atmospheric features in the intensification of a symmetric tropical cyclone vortex, the role of convectively generated asymmetries in creating changes in the azimuthally averaged cyclone is not well understood. In the present study the full-physics nonhydrostatic fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) is used to evaluate the influence of such asymmetries. Rather than adding winds and temperatures in balance with a specified potential vorticity (PV) asymmetry, or temperature perturbations themselves, to a symmetric vortex as in previous studies, a diabatic heating asymmetry is imposed on a spunup model hurricane. The impact of short-duration eyewall-scale monochromatic azimuthal wavenumber diabatic heating on the short- and long-term evolution of the azimuthally averaged vortex is evaluated, and a tangential wind budget is made to determine the mechanisms responsible for the short-term impact.

It is found that the small eddy kick created by the additional diabatic heating asymmetry leads to a substantially amplified long-term change in the azimuthally averaged vortex, with episodes of strong relative weakening and strengthening following at irregular intervals. This behavior is diabatically controlled. It is also found that the symmetric secondary circulation can be active in creating short-term changes in the vortex, and is not simply a passive response as in previous studies with dry physics. A central conclusion of the study is that the structure of the spunup hurricane vortex, in particular preexisting asymmetric features, can have a substantial influence on the character of the response to an additional diabatic heating asymmetry. The results also imply that a small change in the factors that control convective activity will have a substantial lasting consequence for the intensification of a hurricane.
Observations and Analysis of Uncorrelated Rain
Authors: Larsen Michael L. , Kostinski Alexander B. , Tokay Ali
Published: November 2005

Most microphysical models in precipitation physics and radar meteorology assume (at least implicitly) that raindrops are completely uncorrelated in space and time. Yet, several recent studies have indicated that raindrop arrivals are often temporally and spatially correlated. Resolution of this conflict must begin with observations of perfectly uncorrelated rainfall, should such “perfectly steady rain” exist at all. Indeed, it does. Using data with high temporal precision from a two-dimensional video disdrometer and the pair-correlation function, a scale-localized statistical tool, several ∼10–20-min rain episodes have been uncovered where no clustering among droplet arrival times is found. This implies that (i) rain events exist where current microphysical models can be tested in an optimal manner and (ii) not all rain can be properly described using fractals.
Teleconnections from Tropics to Northern Extratropics through a Southerly Conveyor
Authors: Wang Zhuo , Chang C-P. , Wang Bin , Jin Fei-Fei
Published: November 2005

Rossby wave propagation theory predicts that Rossby waves in a tropical easterly flow cannot escape from the Tropics to the extratropics. Here the authors show that a southerly flow component in the basic state (a southerly conveyor) may transfer a Rossby wave source northward; thus, a forcing embedded in the deep tropical easterlies may excite a Rossby wave response in the extratropical westerlies. It is shown that the southerly conveyor determines the location of the effective Rossby wave source and that the extratropical response is relatively insensitive to the location of the tropical forcing, provided that the tropical response can reach the southerly conveyor. A stronger southerly flow favors a stronger extratropical response, and the spatial structure of the extratropical response is determined by the extratropical westerly basic flows.
The Treatment of Adolescents and Young Adults with Acute Lymphoblastic Leukemia
Authors: DeAngelo Daniel J.
Published: November 2005

Intensive chemotherapy regimens for children with acute lymphoblastic leukemia (ALL) have greatly improved, and the majority of children with precursor B-cell ALL are able to achieve a complete remission (CR), with an induction rate approaching 98% and a 5-year estimated event-free survival rate (EFS) of approximately 80%. Although there have been dramatic improvements over the last several decades in both the EFS and overall survival (OS) rates in young children with ALL, the results in adult clinical trials have not kept pace. Current adult treatment regimens result in CR rates in the 80% range, with EFS at 5 years of only 30%–40%. Adolescents and young adults represent a minority of patients enrolled onto either adult or pediatric clinical trials. As a result, little information is available regarding CR, EFS, and OS rates for this age group, and the appropriate treatment regimen for this group of patients remains elusive. Recent studies suggest that young adult patients have far superior outcomes when treated on more intensive pediatric regimens. In addition, new insights into the molecular pathogenesis of T cell ALL have led to new therapeutic strategies.
Management of Polycythemia Vera and Essential Thrombocythemia
Authors: Campbell Peter J. , Green Anthony R.
Published: November 2005

The optimal management of patients with polycythemia vera (PV) and essential thrombocythemia (ET) continues to be controversial. Both diseases present diagnostic challenges and there is a paucity of data from randomized clinical trials to guide therapeutic decisions. However, the past two years have seen major advances in our understanding of these myeloproliferative disorders (MPD). First, the ECLAP study demonstrated the anti-thrombotic efficacy of aspirin in patients with PV.1 Second, the PT-1 trial, the largest randomized study of any MPD, has provided much needed guidance on the optimal management of patients with ET.2 Third, the identification of a single JAK2 mutation in most patients with PV, and in some of those with ET, illuminates the pathogenesis of these diseases and raises questions about the boundary between them.3–7 For the purpose of management decisions, it remains appropriate to consider them as separate entities for the time being. However, as we learn more about the clinical significance of the JAK2 mutation, it seems likely that the coming years will see major changes in the way we classify and manage these disorders.
The Ubiquitin Proteasome Pathway from Bench to Bedside
Authors: Orlowski Robert Z.
Published: November 2005

The validation of the ubiquitin-proteasome pathway as a target for therapy of hematological malignancies stands out as one salient example of the ability to translate laboratory-based findings from the bench to the bedside. Preclinical studies showed that proteasome inhibitors had significant activity against models of non-Hodgkin lymphoma and multiple myeloma, and identified some of the relevant mechanisms of action. These led to phase I through III trials of the first clinically available proteasome inhibitor, bortezomib, which confirmed its activity as a single agent in these diseases. Modulation of proteasome function was then found to be a rational approach to achieve both chemosensitization in vitro and in vivo, as well as to overcome chemotherapy resistance. Based on these findings, first-generation bortezomib-based regimens incorporating traditional chemotherapeutics such as alkylating agents, anthracyclines, immunomodulatory agents, or steroids have been evaluated, and many show promise of enhanced clinical anti-tumor efficacy. Further studies of the pro-and anti-apoptotic actions of proteasome inhibitors, and of their effects on gene and protein expression profiles, suggest that novel agents, such as those targeting the heat shock protein pathways, are exciting candidates for incorporation into these combinations. Phase I trials to test these concepts are just beginning, but have already shown some encouraging results. Finally, novel proteasome inhibitors are being developed with unique properties that may also have therapeutic applications. Taken together, these studies demonstrate the power of rational drug design and development to provide novel, effective therapies for patients with hematological malignancies.
Chronic Lymphocytic Leukemia (CLL): First-Line Treatment
Authors: Hallek Michael ,   On Behalf Of The German CLL Study Group
Published: November 2005

For the past ten years, there has been a dynamic development of new therapeutic compounds and prognostic parameters for chronic lymphocytic leukemia (CLL). Hematologists and oncologists are challenged to use these new possibilities for an optimized, risk- and fitness-adapted treatment strategy, with the goal of achieving long-term remissions and preserving a good quality of life. This review is intended to summarize the current knowledge on first-line treatment of CLL.
Management of Bleeding Disorders in Children
Authors: Manno Catherine S.
Published: November 2005

Diagnosis and management of congenital and acquired bleeding disorders in children requires not only an understanding of the unique characteristics of pediatric hemostasis but also the natural course of bleeding disorders in children, which may differ substantially from the course observed in adult patients. In this article, three bleeding disorders of great importance to the pediatric hematologist are reviewed: neonatal alloimmune thrombocytopenia (NAIT), hemophilia and immune-mediated thrombocytopenic purpura (ITP). Current aspects of management are outlined. The unique physiology of transplacental transfer of maternally derived anti-platelet antibodies can result in neonatal immune thrombocytopenia, a significant cause of morbidity and mortality from bleeding in affected infants. For patients with hemophilia, approaches to treatment have shifted over the past decade from on-demand therapy to prophylaxis, either primary of secondary, resulting in delay of onset or complete avoidance of hemophilic arthropathy. Hemophilic inhibitors often develop in young children, prompting the need for a thorough understanding of the use of bypassing agents as well as immune tolerance induction in the young child. Finally, although several management strategies for ITP of childhood have been shown to improve the platelet count, side effects associated with corticosteroids, IVIg, anti-D and splenectomy force the practitioner to also consider the option of carefully observing, but not treating, the child with ITP.
New Perspectives in Hemophilia Treatment
Authors: Kessler Craig M.
Published: November 2005

A variety of factor concentrates are currently available for replacement therapy for patients with hemophilia. These differ by several parameters, including source (pooled from pooled blood vs recombinant), purity, pathogen inactivation, and by the presence or absence of extraneous proteins such as albumin. The choice of replacement product reflects both safety issues of pathogen transmission or inhibitor development, and personal preferences of the patient and the physician. In general, currently available products are viral pathogen-free, although there is debate about the risk of transmission of parvovirus B19 and prion pathogens. Because of this very small risk, recombinant factor is the treatment of choice in previously untreated patients. In addition, a subset of concentrates contain factor that is activated during manufacture, yielding activated products that can be used in the treatment of patients with inhibitors. Such activated products, especially recombinant factor VIIa (rFVIIa), have also acquired several off-label indications in the management of bleeding in non-hemophiliac patients. The management of hemophilia patients with inhibitors is an ongoing challenge. Immune tolerance induction using a desensitization technique is successful in up to 90% of patients with alloantibodies against factor VIII, with greatest success seen in patients with low titer inhibitors who are treated soon after detection of an alloantibody and in whom treatment includes administration of immunosuppression along with repeated infusions of high titer concentrates. Such therapy is less successful in patients with factor IX alloantibodies. Non-hemophiliac patients with acquired inhibitors represent a unique patient population that requires special management. These patients have a mortality rate that approaches 25% because of the association of acquired inhibitors with severe bleeding complications, occurrence in a largely elderly population, and the frequent presence of an underlying, often serious, primary medical condition. Treatment consists of immunosuppression with steroids, chemotherapy, or intravenous immunoglobulin. Recent studies using rituximab for selective B-cell depletion in these patients have been very promising, although prospective controlled studies have not yet been performed. Finally, although hemophilia A and B appear to be ideal diseases to target with gene therapy approaches, the promise of this therapy remains to be realized.
Integrative Medicine in Hematology/Oncology: Benefits, Ethical Considerations, and Controversies
Authors: Rosenthal David S. , Dean-Clower Elizabeth
Published: November 2005

Integrative Medicine (IM), a newly emerging field, has evolved from Complementary and Alternative Medicine (CAM). CAM refers to diverse medical and health care systems, practices, and products that are not presently considered part of conventional medicine and generally have limited scientific evidence. In the US, CAM is a multi-billion dollar, unregulated industry with potential benefits and risks to consumers, including cancer patients, who are high utilizers of complementary therapies. Patients’ CAM use often is unsupervised by physicians, yet patients need the advice and guidance of their hematologists/oncologists as part of total cancer care. Ethical and legal issues physicians need to address include inquiring about and educating patients regarding potential interactions (e.g., drug-herb, radiation-antioxidant) or product contaminants, while discussing other therapies that may alleviate symptoms and/or improve quality of life. Administratively, CAM offerings in medical settings require relevant policies and procedures, such as properly credentialing practitioners and providing financial assistance counseling for those who cannot afford fee-for-service. Unlike “Alternative Medicine,” the goal of IM is to combine mainstream medical therapies and CAM therapies (e.g., acupuncture, meditation, music therapy) that have some high-quality scientific evidence of safety and effectiveness. The Society for Integrative Oncology (SIO), a new international organization of oncology professionals studying and integrating effective complementary therapies in cancer care, serves as a forum for presenting scientific data on these therapies while emphasizing the importance of developing infrastructure that promotes IM principles and practices. The ultimate goal is to develop multidisciplinary expertise and therapeutic synergy between conventional and complementary therapies.
Bone Marrow Failure: A Child Is Not Just a Small Adult (But an Adult Can Have a Childhood Disease)
Authors: Alter Blanche P.
Published: November 2005

Aplastic anemia may be inherited or acquired. The distinction between these lies not in the age of the patient, but in the clinical and laboratory diagnoses. Adult hematologists must consider adult presentations of the inherited disorders, in order to avoid incorrect management of their patients. Physicians for adult patients must also realize that children with inherited disorders now survive to transition into their care. The major inherited bone marrow failure syndromes associated with development of pancytopenia include Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, and amegakaryocytic thrombocytopenia. The ages at presentation are highly variable, but often include individuals of adult age who have previously undiagnosed Fanconi anemia or dyskeratosis congenita. Many of the genes responsible for these disorders have been identified (12 Fanconi anemia genes, 3 dyskeratosis congenita genes, and 1 each for Shwachman-Diamond syndrome and amegakaryocytic thrombocytopenia). A high index of suspicion and specific testing of children or adults with what appears to be acquired aplastic anemia may identify inherited disorders. Correct classification of patients with aplastic anemia of any age is mandatory for their appropriate management.
Phylogenetic analyses suggest reverse splicing spread of group I introns in fungal ribosomal DNA
Authors: Bhattacharya Debashish , Reeb Valérie , Simon Dawn M , Lutzoni François
Published: November 2005

Background

Group I introns have spread into over 90 different sites in nuclear ribosomal DNA (rDNA) with greater than 1700 introns reported in these genes. These ribozymes generally spread through endonuclease-mediated intron homing. Another putative pathway is reverse splicing whereby a free group I intron inserts into a homologous or heterologous RNA through complementary base-pairing between the intron and exon RNA. Reverse-transcription of the RNA followed by general recombination results in intron spread. Here we used phylogenetics to test for reverse splicing spread in a taxonomically broadly sampled data set of fungal group I introns including 9 putatively ancient group I introns in the rDNA of the yeast-like symbiont Symbiotaphrina buchneri.

Results

Our analyses reveal a complex evolutionary history of the fungal introns with many cases of vertical inheritance (putatively for the 9 introns in S. buchneri) and intron lateral transfer. There are several examples in which introns, many of which are still present in S. buchneri, may have spread through reverse splicing into heterologous rDNA sites. If the S. buchneri introns are ancient as we postulate, then group I intron loss was widespread in fungal rDNA evolution.

Conclusion

On the basis of these results, we suggest that the extensive distribution of fungal group I introns is at least partially explained by the reverse splicing movement of existing introns into ectopic rDNA sites.
Maximal COX-2 and ppRb expression in neurons occurs during early Braak stages prior to the maximal activation of astrocytes and microglia in Alzheimer's disease
Authors: Hoozemans Jeroen JM , van Haastert Elise S , Veerhuis Robert , Arendt Thomas , Scheper Wiep , Eikelenboom Piet , Rozemuller Annemieke JM
Published: November 2005

Neuronal expression of cyclooxygenase-2 (COX-2) and cell cycle proteins is suggested to contribute to neurodegeneration during Alzheimer's disease (AD). The stimulus that induces COX-2 and cell cycle protein expression in AD is still elusive. Activated glia cells are shown to secrete substances that can induce expression of COX-2 and cell cycle proteins in vitro. Using post mortem brain tissue we have investigated whether activation of microglia and astrocytes in AD brain can be correlated with the expression of COX-2 and phosphorylated retinoblastoma protein (ppRb). The highest levels of neuronal COX-2 and ppRb immunoreactivity are observed in the first stages of AD pathology (Braak 0–II, Braak A). No significant difference in COX-2 or ppRb neuronal immunoreactivity is observed between Braak stage 0 and later Braak stages for neurofibrillary changes or amyloid plaques. The mean number of COX-2 or ppRb immunoreactive neurons is significantly decreased in Braak stage C compared to Braak stage A for amyloid deposits. Immunoreactivity for glial markers KP1, CR3/43 and GFAP appears in the later Braak stages and is significantly increased in Braak stage V-VI compared to Braak stage 0 for neurofibrillary changes. In addition, a significant negative correlation is observed between the presence of KP1, CR3/43 and GFAP immunoreactivity and the presence of neuronal immunoreactivity for COX-2 and ppRb. These data show that maximal COX-2 and ppRb immunoreactivity in neurons occurs during early Braak stages prior to the maximal activation of astrocytes and microglia. In contrast to in vitro studies, post mortem data do not support a causal relation between the activation of microglia and astrocytes and the expression of neuronal COX-2 and ppRb in the pathological cascade of AD.
Applying Instructional Design Theories to Bioinformatics Education in Microarray Analysis and Primer Design Workshops
Authors: Shachak Aviv , Ophir Ron , Rubin Eitan
Published: November 2005

The need to support bioinformatics training has been widely recognized by scientists, industry, and government institutions. However, the discussion of instructional methods for teaching bioinformatics is only beginning. Here we report on a systematic attempt to design two bioinformatics workshops for graduate biology students on the basis of Gagne's Conditions of Learning instructional design theory. This theory, although first published in the early 1970s, is still fundamental in instructional design and instructional technology. First, top-level as well as prerequisite learning objectives for a microarray analysis workshop and a primer design workshop were defined. Then a hierarchy of objectives for each workshop was created. Hands-on tutorials were designed to meet these objectives. Finally, events of learning proposed by Gagne's theory were incorporated into the hands-on tutorials. The resultant manuals were tested on a small number of trainees, revised, and applied in 1-day bioinformatics workshops. Based on this experience and on observations made during the workshops, we conclude that Gagne's Conditions of Learning instructional design theory provides a useful framework for developing bioinformatics training, but may not be optimal as a method for teaching it.
Delineating the Tuwu porphyry copper deposit at Xinjiang, China, with seismic-reflection profiling
Authors: Li Tonglin , Eaton David W.
Published: November 2005

The Tuwu deposit is one of a series of recently discovered porphyry copper deposits in the eastern Tian Shan range of Xinjiang, China. Since its discovery in 1997, more than ten boreholes have been drilled and a suite of geophysical surveys has been acquired to delineate the deposit. As part of the geophysical program, a set of eight seismic reflection profiles was acquired in 2000, followed by a physical rock-property study in 2001. The ores are characterized by slightly higher density (Δρ ∼ 0.1 g/cm[Formula: see text]) and significantly higher P-wave velocity ([Formula: see text] ∼ 1.0–1.5 km/s) than the dioritic host rocks. The seismic surveys used 0.6- to 0.9-kg shallow dynamite sources, with a 24-channel end-on spread and offsets up to 350 m. The orebody and associated igneous layers dip steeply (>45°) toward the south, so careful processing of the seismic data was required. Weak reflections from stratigraphic contacts are visible on most of the profiles, including the top of the intrusion and the base of the orebody. Since the observed reflections include a significant out-of-plane component, we developed a simple 2.5D migration procedure. This method was applied to line drawings of the seismic profiles, providing the basis for delineation of the orebody in three dimensions. Synthetic seismic sections computed using the inferred bounding surfaces of the ore deposit are in reasonable agreement with observed reflections, even for along-strike lines not used to build the model. The ability to verify interpreted reflections using line intersections was critical to the development of our model. The results of this work indicate that seismic methods may be useful as an aid for mapping the flanks of shallow, moderately dipping porphyry copper orebodies and associated strata, particularly for defining the structure of deeper sections of the mineralized zones in advance of drilling.
Acquisition and processing strategies for 3D georadar surveying a region characterized by rugged topography
Authors: Heincke Bjoern , Green Alan G. , Kruk Jan van der , Horstmeyer Heinrich
Published: November 2005

Efficiently performing 3D ground-penetrating radar (GPR or georadar) surveys across rugged terrain and then processing the resultant data are challenging tasks. Conventional approaches using unconnected GPR and topographic surveying equipment are excessively time consuming for such environments, and special migration schemes may be required to produce meaningful images. We have collected GPR data across an unstable craggy mountain slope in the Swiss Alps using a novel acquisition system that records GPR and coincident coordinate information simultaneously. Undulating topography (dips of 8° to 16°) and boulders with diameters up to about 2 m complicated the field campaign. After standard processing, the data were found to be plagued by time shifts associated with minor coordinate inaccuracies, uneven antenna-ground coupling, and numerous small gaps in data coverage. These problems were resolved by passing the data sequentially through an adaptive f-xy deconvolution routine and f-[Formula: see text] and f-[Formula: see text] filters. This filtering also reduced incoherent noise. Finally, the data were migrated using a 3D algorithm that accounted for the undulating topography. The nonmigrated and migrated images contained gently and moderately dipping reflections from lithological boundaries and actively opening fracture zones. A suite of prominent diffraction patterns was generated at a steeply dipping fracture zone that projected to the surface. Through this case history we introduce a general strategy for 3D GPR studies of topographically rugged land.
An analysis of 2D and 3D multiple attenuation for a canonical example
Authors: Ikelle Luc T.
Published: November 2005

Three-dimensional formulations of free-surface multiple attenuation for multioffset seismic data are well known. They are not yet used in practice because they require very dense source-receiver coverage, which is still out of reach with existing seismic-acquisition systems. The development of alternative solutions based on 2D algorithms depends on our understanding of the relationship between 2D and 3D free-surface multiple-attenuation methods. This paper attempts to enhance this understanding by establishing the relationship between 2D and 3D inverse scattering free-surface multiple attenuation. A 3D model consisting of three scattering points (one scattered point located in the vertical plane containing the shooting line and the other two points outside this plane) in a homogeneous medium (for which the exact pressure field is analytically known) is used to show that the 2D inverse scattering multiple-attenuation algorithm predicts all free-surface multiples as does its 3D counterpart but with some traveltime and amplitude errors. One implication of this result is that the current 2D inverse scattering multiple-attenuation algorithm, with an appropriate 2D-to-3D correction, can be used to predict the free-surface multiples for data containing out-of-plane scattering.
Efficient compression of borehole resistivity and acoustic imaging data using wavelets
Authors: Li Jiang , Wang Tsili
Published: November 2005

This paper presents a new approach to borehole resistivity and acoustic imaging data compression. The method is based on the discrete wavelet transform (DWT) combined with the set partitioning in the hierarchical trees (SPIHT) coding method. The primary advantages of the DWT + SPIHT method are its superior compression performance, simple implementation, and constant compression and transmission rate control. This new approach generally performs better than the traditional discrete cosine transform (DCT) followed by Huffman coding methods such as JPEG, particularly for target compression ratios greater than 50:1. Image block size plays a key role in using this method. To achieve the best compression performance, the image block size needs to be selected appropriately. In general, large image block sizes and more DWT decomposition levels result in higher compression ratios and/or fewer reconstruction errors. Whenever possible, image block sizes that allow the maximum levels of dyadic DWT decomposition should be used. When insufficient data samples are available in either depth or azimuthal direction, a small number of extra data samples can be added without sacrificing the overall compression performance. The DWT + SPIHT method also shows good fidelity in representing major features in borehole images such as fractures and sinusoids.
Spectral decomposition of seismic data with continuous-wavelet transform
Authors: Sinha Satish , Routh Partha S. , Anno Phil D. , Castagna John P.
Published: November 2005

This paper presents a new methodology for computing a time-frequency map for nonstationary signals using the continuous-wavelet transform (CWT). The conventional method of producing a time-frequency map using the short time Fourier transform (STFT) limits time-frequency resolution by a predefined window length. In contrast, the CWT method does not require preselecting a window length and does not have a fixed time-frequency resolution over the time-frequency space. CWT uses dilation and translation of a wavelet to produce a time-scale map. A single scale encompasses a frequency band and is inversely proportional to the time support of the dilated wavelet.

Previous workers have converted a time-scale map into a time-frequency map by taking the center frequencies of each scale. We transform the time-scale map by taking the Fourier transform of the inverse CWT to produce a time-frequency map. Thus, a time-scale map is converted into a time-frequency map in which the amplitudes of individual frequencies rather than frequency bands are represented. We refer to such a map as the time-frequency CWT (TFCWT).

We validate our approach with a nonstationary synthetic example and compare the results with the STFT and a typical CWT spectrum. Two field examples illustrate that the TFCWT potentially can be used to detect frequency shadows caused by hydrocarbons and to identify subtle stratigraphic features for reservoir characterization.
Intellectual Property
Authors: Walker David A.
Published: November 2005

The Intellectual Property department in each issue of Geophysics provides U.S. patent abstracts, published patent abstracts of U.S. patent applications, and published abstracts filed under the Patent Cooperation Treaty (PCT).
Acute Chemotherapy-Induced Cardiovascular Changes in Patients With Testicular Cancer
Authors: Nuver Janine , Smit Andries J. , van der Meer Jan , van den Berg Maarten P. , van der Graaf Winette T.A. , Meinardi Martin T. , Sleijfer Dirk Th. , Hoekstra Harald J. , van Gessel Anne I. , van Roon Arie M. , Gietema Jourik A.
Published: November 2005

Purpose

After cisplatin- and bleomycin-containing chemotherapy for testicular cancer, part of the patient population will develop acute or long-term cardiovascular toxicity. It is largely unknown whether standard tests can be used to assess chemotherapy-induced cardiovascular changes.

Patients and Methods

In 65 testicular cancer patients (median age, 27 years; range, 18 to 48 years), we measured the following cardiovascular parameters before and within 10 weeks after completion of cisplatin-based chemotherapy: platelet numbers, plasma levels of hemostatic and fibrinolytic factors, 24-hour ambulatory blood pressure, baroreflex sensitivity, intima-media thickness of the common carotid artery, and flow-mediated vasodilation of the brachial artery.

Results

Compared with prechemotherapy values, the intima-media thickness of the carotid artery and plasma von Willebrand factor levels increased significantly after treatment. Platelet numbers and plasma levels of other hemostatic and fibrinolytic factors did not appear to change significantly. Blood pressure decreased significantly, but flow-mediated vasodilation and baroreflex sensitivity did not change.

Conclusion

In testicular cancer patients treated with cisplatin-based chemotherapy, we found an increase in plasma von Willebrand factor levels and in the intima-media thickness of the carotid artery. These changes may indicate chemotherapy-induced vascular damage and be of prognostic significance for the development of cardiovascular complications in the long term.
A protein related to the vaccinia virus cap-specific methyltransferase VP39 is involved in cap 4 modification in Trypanosoma brucei
Authors: ARHIN GEORGE K. , LI HONGJIE , ULLU ELISABETTA , TSCHUDI CHRISTIAN
Published: November 2005

The spliced-leader (SL) RNA plays a key role in the biogenesis of mRNA in trypanosomes by providing the m7G-capped SL sequence to the 5′ end of every mRNA. The cap structure of the SL RNA is unique in eukaryotes with 4 nucleotides after the cap carrying a total of seven methyl groups and by convention is referred to as “cap 4”. Although the enzymatic machinery for cap addition has been characterized in several organisms, including Trypanosoma brucei, the identification of methyltransferases dedicated to the generation of higher order cap structures has lagged behind, except in viruses. Here we describe T. brucei MT57 (TbMT57), a primarily nuclear polypeptide with structural and functional similarities to vaccinia virus VP39, a bifunctional protein acting at the mRNA 5′ end as a cap-specific 2′-O-methyltransferase. Down-regulation by RNAi or genetic ablation of TbMT57 resulted in the accumulation of SL RNA missing 2′-O-methyl groups at positions +3 and +4 and thus bearing a cap 2 rather than a cap 4. Furthermore, competitive binding studies indicated that modifications at the +3 and +4 positions are important for binding to the nuclear cap-binding complex. Genetic ablation of MT57 resulted in viable cells with no apparent defect in SL RNA trans-splicing, suggesting that MT57 is not essential or that trypanosomes have developed alternate mechanisms to counteract the absence of this protein. Interestingly, MT57 homologs are only found in trypanosomatid protozoa that have a cap 4 structure and in poxviruses, of which vaccinia virus is a prototype.
A Staffing Algorithm for Call Centers with Skill-Based Routing
Authors: Wallace Rodney B. , Whitt Ward
Published: November 2005

Call centers usually handle several types of calls, but it is usually not possible or cost effective to have every agent be able to handle every type of call. Thus, the agents tend to have different skills, in different combinations. In such an environment, it is challenging to route calls effectively and determine the staff requirements. This paper addresses both of these routing and staffing problems by exploiting limited cross-training. Consistent with the literature on flexible manufacturing, we find that minimal flexibility can provide great benefits: Simulation experiments show that when (1) the service-time distribution does not depend on the call type or the agent and (2) each agent has only two skills, in appropriate combinations, the performance is almost as good as when each agent has all skills. We apply this flexibility property to develop an algorithm for both routing and staffing, aiming to minimize the total staff subject to per-class performance constraints. With appropriate flexibility, it suffices to use a suboptimal routing algorithm. Simulation experiments show that the overall procedure can be remarkably effective: The required staff with limited cross-training can be nearly the same as if all agents had all skills. Hence, the overall algorithm is nearly optimal for that scenario.
The Profitable Arc Tour Problem: Solution with a Branch-and-Price Algorithm
Authors: Feillet Dominique , Dejax Pierre , Gendreau Michel
Published: November 2005

In this article, we introduce a new arc routing problem that we call the profitable arc tour problem. This problem is defined on a graph in which profits and travel costs are associated with the arcs. The objective is to find a set of cycles in the graph that maximizes the collection of profit minus travel costs, subject to constraints limiting the number of times that profit is available on arcs and the maximal length of cycles. The problem is related both to constrained flow problems and to vehicle-routing problems. We tackle it from this standpoint and propose a branch-and-price algorithm for its solution. In the column-generation phase, the issue of the collection decisions while traveling through the arcs is addressed. In the branching phase, the fact that viewing solutions in terms of flow variables regularly induces an integer flow matrix leads us to introduce a branching method called the flow-splitting method. Finally, the relationships of this problem with constrained flow optimization are taken into account in an initial phase of the algorithm.
Simulation der zerebralen Hämodynamik zur präoperativen Risikoeinschätzung (Simulation of Cerebral Hemodynamics for Preoperative Risk-estimation)
Authors: Roessler Florian C. , Reith Wolfgang , Siegel Günter
Published: November 2005

Vorgestellt wird ein Verfahren zur präoperativen, nichtinvasiven Risikoabschätzung von Gefäßverschlüssen bei neuroradiologischen oder neurochirurgischen Interventionen. Es basiert auf einer computergestützten, zeitvarianten, pulsatilen, nichtlinearen und individuellen Simulation der Hämodynamik intrakranieller Gefäßsysteme. Auf diese Weise sollen riskante, invasive Diagnoseverfahren ersetzt werden.
Ein Ansatz zur dynamischen Modellierung der Genexpression mit Shegalkin-Polynomen (An Appraoch to Dynamic Modelling of Gene Expression by Zhegalkin Polynomials)
Authors: Lichtenberg Gerwald , Faisal Saadia , Werner Herbert
Published: November 2005

Der Beitrag beschreibt einen neuen Ansatz zur Modellierung des dynamischen Verhaltens der Genexpression. Im Gegensatz zu bekannten Modellbildungsmethoden können mit Hilfe der vorgestellten Methode sowohl diskrete biologische Regeln, wie z.B. die kanalisierende Eigenschaft der Gen-Wechselwirkung als auch kontinuierliche Messdaten berücksichtigt werden. Dies wird ermöglicht durch die Anwendung kontinuierlicher Shegalkin-Polynome, die Boole'sche Funktionen repräsentieren können.
Self-Reports of Psychosocial Functioning among Children and Young Adults with Cleft Lip and Palate
Authors: Hunt Orlagh , Burden Donald , Hepper Peter , Stevenson Mike , Johnston Chris
Published: November 2005

Objective:

A cross-sectional study was employed to determine the psychosocial effects of cleft lip and/or palate among children and young adults, compared with a control group of children and young adults without cleft lip and palate.

Participants:

The study comprised 160 children and young adults with cleft lip and/or palate and 113 children and young adults without cleft lip and/or palate. All participants were between 8 and 21 years of age.

Outcome measures:

Psychological functioning (anxiety, self-esteem, depression, and behavioral problems) was assessed using validated psychological questionnaires. Happiness with facial appearance was rated using a visual analog scale. Social functioning, including experience of teasing/bullying and satisfaction with speech, was assessed using a semistructured interview.

Results:

Participants with cleft lip and/or palate reported greater behavioral problems (p < .001) and more symptoms of depression (p < .01); they were teased more often (p < .001) and were less happy with their facial appearance (p < .01) and speech (p < .001), compared with controls. There were no significant difference between subjects with cleft lip and/or palate and subjects without cleft lip and/or palate in terms of anxiety (p > .05) or self-esteem (p > .05). Having been teased was a significant predictor of poor psychological functioning, more so than having a cleft lip and/or palate per se (p < .001).

Conclusions:

Teasing was greater among participants who had cleft lip and/ or palate and it was a significant predictor of poorer psychosocial functioning. Children and young adults with cleft lip and/or palate require psychological assessment, specifically focusing on their experience of teasing, as part of their routine cleft care.