246 research outputs found

    The parameterized complexity of some geometric problems in unbounded dimension

    Full text link
    We study the parameterized complexity of the following fundamental geometric problems with respect to the dimension dd: i) Given nn points in \Rd, compute their minimum enclosing cylinder. ii) Given two nn-point sets in \Rd, decide whether they can be separated by two hyperplanes. iii) Given a system of nn linear inequalities with dd variables, find a maximum-size feasible subsystem. We show that (the decision versions of) all these problems are W[1]-hard when parameterized by the dimension dd. %and hence not solvable in O(f(d)nc){O}(f(d)n^c) time, for any computable function ff and constant cc %(unless FPT=W[1]). Our reductions also give a nΩ(d)n^{\Omega(d)}-time lower bound (under the Exponential Time Hypothesis)

    Estimation in high dimensions: a geometric perspective

    Full text link
    This tutorial provides an exposition of a flexible geometric framework for high dimensional estimation problems with constraints. The tutorial develops geometric intuition about high dimensional sets, justifies it with some results of asymptotic convex geometry, and demonstrates connections between geometric results and estimation problems. The theory is illustrated with applications to sparse recovery, matrix completion, quantization, linear and logistic regression and generalized linear models.Comment: 56 pages, 9 figures. Multiple minor change

    The cyclin-dependent kinase inhibitor p57(Kip2) is epigenetically regulated in carboplatin resistance and results in collateral sensitivity to the CDK inhibitor seliciclib in ovarian cancer

    Get PDF
    Carboplatin remains a first-line agent in the management of epithelial ovarian cancer (EOC). Unfortunately, platinum-resistant disease ultimately occurs in most patients. Using a novel EOC cell line with acquired resistance to carboplatin: PEO1CarbR, genome-wide micro-array profiling identified the cyclin-dependent kinase inhibitor p57(Kip2) as specifically downregulated in carboplatin resistance. Presently, we describe confirmation of these preliminary data with a variety of approaches

    EPTAS and Subexponential Algorithm for Maximum Clique on Disk and Unit Ball Graphs

    Get PDF
    A (unit) disk graph is the intersection graph of closed (unit) disks in the plane. Almost three decades ago, an elegant polynomial-time algorithm was found for Maximum Cliqe on unit disk graphs [Clark, Colbourn, Johnson; Discrete Mathematics ’90]. Since then, it has been an intriguing open question whether or not tractability can be extended to general disk graphs. We show that the disjoint union of two odd cycles is never the complement of a disk graph nor of a unit (3-dimensional) ball graph. From that fact and existing results, we derive a simple QPTAS and a subexponential algorithm running in time 2O˜(n2/3) for Maximum Cliqe on disk and unit ball graphs. We then obtain a randomized EPTAS for computing the independence number on graphs having no disjoint union of two odd cycles as an induced subgraph, bounded VC-dimension, and linear independence number. This, in combination with our structural results, yields a randomized EPTAS for Max Cliqe on disk and unit ball graphs. Max Cliqe on unit ball graphs is equivalent to finding, given a collection of points in R3, a maximum subset of points with diameter at most some fixed value. In stark contrast, Maximum Cliqe on ball graphs and unit 4-dimensional ball graphs, as well as intersection graphs of filled ellipses (even close to unit disks) or filled triangles is unlikely to have such algorithms. Indeed, we show that, for all those problems, there is a constant ratio of approximation which cannot be attained even in time 2n1−Δ, unless the Exponential Time Hypothesis fails

    Prediction of disease severity in multiple acyl-CoA dehydrogenase deficiency:a retrospective and laboratory cohort study

    Get PDF
    Multiple acyl-CoA dehydrogenase deficiency (MADD) is an ultra-rare inborn error of mitochondrial fatty acid oxidation (FAO) and amino acid metabolism. Individual phenotypes and treatment response can vary markedly. We aimed to identify markers that predict MADD phenotypes. We performed a retrospective nationwide cohort study; then developed an MADD-disease severity scoring system (MADD-DS3) based on signs and symptoms with weighed expert opinions; and finally correlated phenotypes and MADD-DS3 scores to FAO flux (oleate and myristate oxidation rates) and acylcarnitine profiles after palmitate loading in fibroblasts. Eighteen patients, diagnosed between 1989 and 2014, were identified. The MADD-DS3 entails enumeration of eight domain scores, which are calculated by averaging the relevant symptom scores. Lifetime MADD-DS3 scores of patients in our cohort ranged from 0 to 29. FAO flux and [U-13C]C2-, C5-, and [U-13C]C16-acylcarnitines were identified as key variables that discriminated neonatal from later onset patients (all P <.05) and strongly correlated to MADD-DS3 scores (oleate: r = −.86; myristate: r = −.91; [U-13C]C2-acylcarnitine: r = −.96; C5-acylcarnitine: r =.97; [U-13C]C16-acylcarnitine: r =.98, all P <.01). Functional studies in fibroblasts were found to differentiate between neonatal and later onset MADD-patients and were correlated to MADD-DS3 scores. Our data may improve early prediction of disease severity in order to start (preventive) and follow-up treatment appropriately. This is especially relevant in view of the inclusion of MADD in population newborn screening programs

    DIANA-microT web server: elucidating microRNA functions through target prediction

    Get PDF
    Computational microRNA (miRNA) target prediction is one of the key means for deciphering the role of miRNAs in development and disease. Here, we present the DIANA-microT web server as the user interface to the DIANA-microT 3.0 miRNA target prediction algorithm. The web server provides extensive information for predicted miRNA:target gene interactions with a user-friendly interface, providing extensive connectivity to online biological resources. Target gene and miRNA functions may be elucidated through automated bibliographic searches and functional information is accessible through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The web server offers links to nomenclature, sequence and protein databases, and users are facilitated by being able to search for targeted genes using different nomenclatures or functional features, such as the genes possible involvement in biological pathways. The target prediction algorithm supports parameters calculated individually for each miRNA:target gene interaction and provides a signal-to-noise ratio and a precision score that helps in the evaluation of the significance of the predicted results. Using a set of miRNA targets recently identified through the pSILAC method, the performance of several computational target prediction programs was assessed. DIANA-microT 3.0 achieved there with 66% the highest ratio of correctly predicted targets over all predicted targets. The DIANA-microT web server is freely available at www.microrna.gr/microT

    Splenic rupture as the presenting manifestation of primary splenic angiosarcoma in a teenage woman: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Primary splenic angiosarcoma is a rare neoplasm of vascular origin carrying a very poor prognosis, partly due to its high metastatic potential. This disease presents frequently with splenic rupture and hemorrhage. We report the case of a 17-year-old woman who presented with rupture of a primary splenic angiosarcoma.</p> <p>Case presentation</p> <p>The patient presented with diffuse abdominal pain and distention. Clinical examination revealed severe tenderness in the left upper abdominal quadrant, a palpable abdominal mass, and hemodynamic instability with a systolic arterial blood pressure of 75 mmHg and heart rate of 135 beats per minute. Blood tests revealed anemia (hemoglobin 7.0 g/dl) and thrombocytopenia (platelets 70 × 10<sup>9</sup>/liter). After initial fluid resuscitation and stabilization, abdominal ultrasound and computed tomography were performed, revealing a large quantity of intraperitoneal free fluid, an enlarged spleen, and a heterogeneous low-density signal within the splenic parenchyma, which showed varying degrees of contrast enhancement. At laparotomy a huge (weight 1530 g, diameter 19 cm) actively bleeding spleen was identified and splenectomy was performed. Histopathology showed a primary splenic angiosarcoma. After an uneventful recovery, the patient was discharged on the sixth postoperative day.</p> <p>Conclusion</p> <p>Primary splenic angiosarcoma is rare. Although this malignancy is usually encountered in advanced age, there have been a few reported cases among younger patients. The case reported here presented with splenic rupture, was treated by laparotomy and splenectomy, and the patient is disease free 16 months after surgery.</p

    Restoring the valence-shell stabilization in Nd-140

    Get PDF
    A projectile Coulomb-excitation experiment was performed at the radioactive-ion beam facility HIE-ISOLDE at CERN to obtain E2 and M1 transition matrix elements of Nd-140 using the multistep Coulomb-excitation code GOSIA. The absolute M1 strengths, B(M1; 2(2)(-) -> 2(1)(+)) = 0.033(8)mu(2)(N), B(M1 ; 2(3)(+) -> 2(1)(+)) = 0.26(-0.10)(+0.11)mu(2)(N), and B(M1; 2(4)+ -> 2(1)(+)) <0.04 mu(2)(N) identify the 2(3)(+) state as the main fragment of the one-quadrupole-phonon proton-neutron mixed-symmetry state of Nd-140. The degree of F-spin mixing in Nd-140 was quantified with the determination of the mixing matrix element VF-mix <7(-7)(-13) keV.Peer reviewe
    • 

    corecore