1,542 research outputs found
Boat-towed radio-magnetotellurics — A new technique and case study from the city of Stockholm
FLEET: Butterfly Estimation from a Bipartite Graph Stream
We consider space-efficient single-pass estimation of the number of
butterflies, a fundamental bipartite graph motif, from a massive bipartite
graph stream where each edge represents a connection between entities in two
different partitions. We present a space lower bound for any streaming
algorithm that can estimate the number of butterflies accurately, as well as
FLEET, a suite of algorithms for accurately estimating the number of
butterflies in the graph stream. Estimates returned by the algorithms come with
provable guarantees on the approximation error, and experiments show good
tradeoffs between the space used and the accuracy of approximation. We also
present space-efficient algorithms for estimating the number of butterflies
within a sliding window of the most recent elements in the stream. While there
is a significant body of work on counting subgraphs such as triangles in a
unipartite graph stream, our work seems to be one of the few to tackle the case
of bipartite graph streams.Comment: This is the author's version of the work. It is posted here by
permission of ACM for your personal use. Not for redistribution. The
definitive version was published in Seyed-Vahid Sanei-Mehri, Yu Zhang, Ahmet
Erdem Sariyuce and Srikanta Tirthapura. "FLEET: Butterfly Estimation from a
Bipartite Graph Stream". The 28th ACM International Conference on Information
and Knowledge Managemen
Автоматизация участка электрической сети 10 кВ для электроснабжения потребителей Новобелицкого района
We have developed a new data acquisition system and technique to measure the radio magnetotelluric (RMT) signals from distant radio transmitters with the objective of mapping and modeling electric resistivity structures below a river or lake. The acquisition system is towed by a boat; therefore, we call the technique boat-towed RMT. The data acquisition is fast with a production rate of approximately 1 km/hr using a nominal sampling spacing of 10–15 m. Given the ample number of radio transmitters available in most parts of the world, the method can be used for near-surface studies of various targets. We have developed boat-towed RMT measurements on Lake Mälaren near the city of Stockholm in Sweden to determine the feasibility of the method. Approximately 15 km of RMT data were collected during three days above a planned 60-m-deep bypass tunnel with the goal of providing information on the bedrock depth and possible weak zones within the bedrock. The measured resistivity and phase data were of high quality with errors on the order of a few percent. The resistivity models from 2D inversion of the data showed a good correlation with available geologic data in resolving bedrock depth and also resistivity layering within the lake. Resistivity maps derived from the dense 2D models suggested a northeast–southwest-striking low-resistivity zone at less than a 30-m depth. The zone likely represents fractured crystalline bedrock. The boat-towed RMT technique is well suited for water bodies with moderate electric resistivity such as in brackish and freshwater environments
Serum nitrite level and adenosine deaminase activity is altered in visceral leishmaniasis
ABSTRACT In this study we sought to determine if there is alteration in nitric oxide (NO) production and adenosine deaminase (ADA) activity among patients with visceral leishmaniasis (VL) and the effect of four weeks of chemotherapy on these levels. Fifty-three VL patients diagnosed clinically and by direct demonstration of the LD bodies in the bone marrow smear were studied. They were treated with Sodium Stibogluconate and sampled at the baseline and four weeks. Forty-three healthy individuals coming from the same endemic area were taken as control. Total nitrite Keywords: NO, ADA, Visceral leishmaniasis INTRODUCTION Intramacrophage infection by Leishmania donovani (LD), an obligate intracellular protozoan, results the potentially fatal visceral leishmaniasis (VL) or kalaazar. The elimination of leishmania parasite by macrophage depends upon the mounting of effective cell-mediated immune response. During leishmaniasis infection, the microbicidal interaction between the parasite and host cells involves the presentation of leishmania antigen by macrophage to T-helper (Th) cell through MHC II molecule along with the co-stimulatory molecules (B7-1/B7-2 and CD40). 1, 2 Activation of Th cell causes proliferation of IFN-γ producing CD4+ Th subset. 3 IFN-γ and TNF-α, the defining cytokines of the Th1 subset in turn activates the macrophage to generate NO which is the most relevant anti-leishmanial oxidant. Contrary results have been found in the NO level during L. donovani infection both in vitro and in vivo experiments. 4, 5 Also studies reported hitherto have generally originated from in vitro culture and animal experiments. However no study has so far been conducted to investigate NO production in patients with visceral leishmaniasis. Therefore we aimed to determine serum nitrite level in VL patients as surrogate marker of NO production and compare it with the healthy subjects. Assessments of NO metabolites may be useful tool in the evaluation of the effector mechanism of macrophage and clinical manifestation of patients. Adenosine deaminase (ADA) is an essential for the proliferation, maturation and function of T lymphocytes. Its activity increases during antigenic and mitogenic responses of lymphocytes and is considered as an important immunoenzyme marker for assessing cell-mediated immunity in diseases characterized by T lymphocytes proliferation and maturation
Endocrine therapy for hormone receptor-positive metastatic breast cancer: American Society of Clinical Oncology Guideline
PURPOSE: To develop recommendations about endocrine therapy for women with hormone receptor (HR) -positive metastatic breast cancer (MBC).
METHODS: The American Society of Clinical Oncology convened an Expert Panel to conduct a systematic review of evidence from 2008 through 2015 to create recommendations informed by that evidence. Outcomes of interest included sequencing of hormonal agents, hormonal agents compared with chemotherapy, targeted biologic therapy, and treatment of premenopausal women. This guideline puts forth recommendations for endocrine therapy as treatment for women with HR-positive MBC.
RECOMMENDATIONS: Sequential hormone therapy is the preferential treatment for most women with HR-positive MBC. Except in cases of immediately life-threatening disease, hormone therapy, alone or in combination, should be used as initial treatment. Patients whose tumors express any level of hormone receptors should be offered hormone therapy. Treatment recommendations should be based on type of adjuvant treatment, disease-free interval, and organ function. Tumor markers should not be the sole criteria for determining tumor progression; use of additional biomarkers remains experimental. Assessment of menopausal status is critical; ovarian suppression or ablation should be included in premenopausal women. For postmenopausal women, aromatase inhibitors (AIs) are the preferred first-line endocrine therapy, with or without the cyclin-dependent kinase inhibitor palbociclib. As second-line therapy, fulvestrant should be administered at 500 mg with a loading schedule and may be administered with palbociclib. The mammalian target of rapamycin inhibitor everolimus may be administered with exemestane to postmenopausal women with MBC whose disease progresses while receiving nonsteroidal AIs. Among patients with HR-positive, human epidermal growth factor receptor 2-positive MBC, human epidermal growth factor receptor 2-targeted therapy plus an AI can be effective for those who are not chemotherapy candidates
Molecular mechanisms of drug resistance in natural Leishmania populations vary with genetic background
The evolution of drug-resistance in pathogens is a major global health threat. Elucidating the molecular basis of pathogen drug-resistance has been the focus of many studies but rarely is it known whether a drug-resistance mechanism identified is universal for the studied pathogen; it has seldom been clarified whether drug-resistance mechanisms vary with the pathogen's genotype. Nevertheless this is of critical importance in gaining an understanding of the complexity of this global threat and in underpinning epidemiological surveillance of pathogen drug resistance in the field. This study aimed to assess the molecular and phenotypic heterogeneity that emerges in natural parasite populations under drug treatment pressure. We studied lines of the protozoan parasite Leishmania (L.) donovani with differential susceptibility to antimonial drugs; the lines being derived from clinical isolates belonging to two distinct genetic populations that circulate in the leishmaniasis endemic region of Nepal. Parasite pathways known to be affected by antimonial drugs were characterised on five experimental levels in the lines of the two populations. Characterisation of DNA sequence, gene expression, protein expression and thiol levels revealed a number of molecular features that mark antimonial-resistant parasites in only one of the two populations studied. A final series of in vitro stress phenotyping experiments confirmed this heterogeneity amongst drug-resistant parasites from the two populations. These data provide evidence that the molecular changes associated with antimonial-resistance in natural Leishmania populations depend on the genetic background of the Leishmania population, which has resulted in a divergent set of resistance markers in the Leishmania populations. This heterogeneity of parasite adaptations provides severe challenges for the control of drug resistance in the field and the design of molecular surveillance tools for widespread applicability
Broadly cross-reactive antibodies dominate the human B cell response against 2009 pandemic H1N1 influenza virus infection
Although scarce after annual influenza vaccination, B cells producing antibodies capable of neutralizing multiple influenza strains are abundant in humans infected with pandemic 2009 H1N1 influenza
Gauge bosons at zero and finite temperature
Gauge theories of the Yang-Mills type are the single most important building
block of the standard model and beyond. Since Yang-Mills theories are gauge
theories their elementary particles, the gauge bosons, cannot be described
without fixing a gauge. Beyond perturbation theory, gauge-fixing in non-Abelian
gauge theories is obstructed by the Gribov-Singer ambiguity. The construction
and implementation of a method-independent gauge-fixing prescription to resolve
this ambiguity is the most important step to describe gauge bosons beyond
perturbation theory. Proposals for such a procedure, generalizing the
perturbative Landau gauge, are described here. Their implementation are
discussed for two example methods, lattice gauge theory and the quantum
equations of motion. The most direct access to the properties of the gauge
bosons is provided by their correlation functions. The corresponding two- and
three-point correlation functions are presented at all energy scales. These
give access to the properties of the gauge bosons, like their absence from the
asymptotic physical state space, the absence of an on-shell mass pole,
particle-like properties at high energies, and their running couplings.
Furthermore, auxiliary degrees of freedom are introduced during gauge-fixing,
and their properties are discussed as well. These results are presented for
two, three, and four dimensions, and for various gauge algebras. Finally, the
modifications of the properties of gauge bosons at finite temperature are
presented. Evidence is provided that these reflect the phase structure of
Yang-Mills theory. However, it is found that the phase transition is not
deconfining the gauge bosons, although the bulk thermodynamical behavior is of
a Stefan-Boltzmann type. The resolution of this apparent contradiction is also
presented. This resolution also provides an explicit and constructive solution
to the Linde problem.Comment: v2: 153 pages, 45 figures, revised, updated, and extended version
submitted on invitation to Physics Reports; v3: Intermediate update, 152
pages, 45 figures, minor errors corrected, reference list extended; v3 minor
typographical changes and corrections, added references, version to appear in
Physics Report
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