1,119 research outputs found
\epsilon-regularity for systems involving non-local, antisymmetric operators
We prove an epsilon-regularity theorem for critical and super-critical
systems with a non-local antisymmetric operator on the right-hand side.
These systems contain as special cases, Euler-Lagrange equations of
conformally invariant variational functionals as Rivi\`ere treated them, and
also Euler-Lagrange equations of fractional harmonic maps introduced by Da
Lio-Rivi\`ere.
In particular, the arguments presented here give new and uniform proofs of
the regularity results by Rivi\`ere, Rivi\`ere-Struwe, Da-Lio-Rivi\`ere, and
also the integrability results by Sharp-Topping and Sharp, not discriminating
between the classical local, and the non-local situations
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Ethnically Biased? Experimental Evidence from Kenya
Ethnicity has been shown to shape political, social, and economic behavior in Africa, but the underlying mechanisms remain contested. We utilize lab experiments to isolate one mechanism - an individual's bias in favor of coethnics and against non-coethnics - that has been central in both theory and in the conventional wisdom about the impact of ethnicity. We employ an unusually rich research design involving a large sample of 1300 participants from Nairobi, Kenya; the collection of multiple rounds of experimental data with varying proximity to national elections; within-lab priming conditions; both standard and novel experimental measures of coethnic bias; and an implicit association test (IAT). We find very little evidence of an ethnic bias in the behavioral games, which runs against the common presumption of extensive coethnic bias among ordinary Africans and suggests that mechanisms other than a coethnic bias in preferences must account for the associations we see in the region between ethnicity and political, social, and economic outcomes
Parallel swarm intelligence strategies for large-scale clustering based on MapReduce with application to epigenetics of aging
Clustering is an important technique for data analysis and knowledge discovery. In the context of big data, it becomes a challenging issue due to the huge amount of data recently collected making conventional clustering algorithms inappropriate. The use of swarm intelligence algorithms has shown promising results when applied to data clustering of moderate size due to their decentralized and self-organized behavior. However, these algorithms exhibit limited capabilities when large data sets are involved. In this paper, we developed a decentralized distributed big data clustering solution using three swarm intelligence algorithms according to MapReduce framework. The developed framework allows cooperation between the three algorithms namely particle swarm optimization, ant colony optimization and artificial bees colony to achieve largely scalable data partitioning through a migration strategy. This latter reaps advantage of the combined exploration and exploitation capabilities of these algorithms to foster diversity. The framework is tested using amazon elastic map-reduce service (EMR) deploying up to 192 computer nodes and 30 gigabytes of data. Parallel metrics such as speed-up, size-up and scale-up are used to measure the elasticity and scalability of the framework. Our results are compared with their counterparts big data clustering results and show a significant improvement in terms of time and convergence to good quality solution. The developed model has been applied to epigenetics data clustering according to methylation features in CpG islands, gene body, and gene promoter in order to study the epigenetics impact on aging. Experimental results reveal that DNA-methylation changes slightly and not aberrantly with aging corroborating previous studies
The Tychonoff uniqueness theorem for the G-heat equation
In this paper, we obtain the Tychonoff uniqueness theorem for the G-heat
equation
Are Endothelial Progenitor Cells the Real Solution for Cardiovascular Diseases? Focus on Controversies and Perspectives
Advanced knowledge in the field of stem cell biology and their ability to provide a cue for counteracting several diseases are
leading numerous researchers to focus their attention on \u201cregenerative medicine\u201d as possible solutions for cardiovascular diseases
(CVDs). However, the lack of consistent evidence in this arena has hampered the clinical application. The same condition affects
the research on endothelial progenitor cells (EPCs), creating more confusion than comprehension. In this review, this aspect is
discussed with particular emphasis. In particular, we describe biology and physiology of EPCs, outline their clinical relevance as
both new predictive, diagnostic, and prognostic CVD biomarkers and therapeutic agents, discuss advantages, disadvantages, and
conflicting data about their use as possible solutions for vascular impairment and clinical applications, and finally underline a very
crucial aspect of EPCs \u201ccharacterization and definition,\u201d which seems to be the real cause of large heterogeneity existing in literature
data on this topic
Back-translation for discovering distant protein homologies
Frameshift mutations in protein-coding DNA sequences produce a drastic change
in the resulting protein sequence, which prevents classic protein alignment
methods from revealing the proteins' common origin. Moreover, when a large
number of substitutions are additionally involved in the divergence, the
homology detection becomes difficult even at the DNA level. To cope with this
situation, we propose a novel method to infer distant homology relations of two
proteins, that accounts for frameshift and point mutations that may have
affected the coding sequences. We design a dynamic programming alignment
algorithm over memory-efficient graph representations of the complete set of
putative DNA sequences of each protein, with the goal of determining the two
putative DNA sequences which have the best scoring alignment under a powerful
scoring system designed to reflect the most probable evolutionary process. This
allows us to uncover evolutionary information that is not captured by
traditional alignment methods, which is confirmed by biologically significant
examples.Comment: The 9th International Workshop in Algorithms in Bioinformatics
(WABI), Philadelphia : \'Etats-Unis d'Am\'erique (2009
An Optimal Execution Problem with Market Impact
We study an optimal execution problem in a continuous-time market model that
considers market impact. We formulate the problem as a stochastic control
problem and investigate properties of the corresponding value function. We find
that right-continuity at the time origin is associated with the strength of
market impact for large sales, otherwise the value function is continuous.
Moreover, we show the semi-group property (Bellman principle) and characterise
the value function as a viscosity solution of the corresponding
Hamilton-Jacobi-Bellman equation. We introduce some examples where the forms of
the optimal strategies change completely, depending on the amount of the
trader's security holdings and where optimal strategies in the Black-Scholes
type market with nonlinear market impact are not block liquidation but gradual
liquidation, even when the trader is risk-neutral.Comment: 36 pages, 8 figures, a modified version of the article "An optimal
execution problem with market impact" in Finance and Stochastics (2014
Age and Cytokine Gene Variants Modulate the Immunogenicity and Protective Effect of SARS-CoV-2 mRNA-Based Vaccination
: The introduction of anti-SARS-CoV-2 vaccines in late 2020 substantially changed the pandemic picture, inducing effective protection in the population. However, individual variability was observed with different levels of cellular response and neutralizing antibodies. We report data on the impact of age, gender, and 16 single nucleotide polymorphisms (SNPs) of cytokine genes on the anti-SARS-CoV-2 IgG titers measured 31 and 105 days after administration of the second dose of BNT162b2 vaccine to 122 healthy subjects from the health care staff of the Palermo University Hospital, Italy. The higher titers at 31 days were measured in the younger subjects and in subjects bearing T-positive genotypes of IL-1R1 rs2234650 or the GG homozygous genotype of IL-6 rs1800795 SNP. T-positive genotypes are also significantly more common in subjects with higher titers at day 105. In addition, in this group of subjects, the frequency of the CT genotype of IL-4 rs2243250 is higher among those vaccinated with higher titers. Moreover, these SNPs and TNFA rs1800629 are differently distributed in a group of subjects that were found infected by SARS-CoV-2 at day 105 of evaluation. Finally, subjects that were found to be infected by SARS-CoV-2 at day 105 were significantly older than the uninfected subjects. Taken together, these data seem to suggest that age and polymorphisms of key cytokines, which regulate inflammation and humoral immune response, might influence the magnitude of the antibody response to vaccination with BNT162B2, prompting speculation about the possible benefit of a genetic background-based assessment of a personalized approach to the anti-COVID vaccination schedule
A double-negative (IgD CD27 ) B cell population is increased in the peripheral blood of elderly people
The T cell branch of the immune system has been extensively studied in the elderly and it is known that
the elderly have impaired immune function, mainly due to the chronic antigenic load that ultimately
causes shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In the
present paper,we describe the IgD CD27 double-negative B cell population which (aswe have recently
described) is higher in the elderly. Most of these cells were IgG+. Evaluation of the telomere length and
expression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have the
markers of memory B cells. We also show that these cells do not act as antigen presenting cells, as
indicated by the low levels of CD80 and DR, nor do they express significant levels of the CD40 molecule
necessary to interact with T lymphocytes through the ligand, CD154. Hence, we hypothesize that these
expanded cells are late memory or exhausted cells that have down-modulated the expression of CD27
and filled the immunologic space in the elderly. These cells might be the age-related manifestation of
time-enduring stimulation or dysregulation of the immune system
Infezioni di Cylindrocarpon obtusisporium su piante di vite in Sicilia
Da barbatelle dell'ibrido 225 Ruggeri con sviluppo stentato e imbrunimenti del legno, ai quali corrispondevano accumuli di gomma nei vasi dello xilema, provenienti da un vivaio siciliano, è stata isolata una specie fungina identificata come Cylindrocarpon obtusisporium WOLLENW. Inoculando il fungo su talee dello stesso portinnesto è stata riprodotta la sindrome osservata nelle infezioni naturali e dal legno imbrunito si è potuto poi reisolare tale agente patogeno. Si conclude che i fenomeni di deperimento riscontrati sulle barbatelle di vite in vivaio sono causati da infezioni di C. obtusisporium, specie, a quanto risulta, non ancora segnalata su Vitis.Infections of Cylindrocarpon obtusisporium on grapevines in SicilyA decline of rooted cuttings of the grapevine hybrid 225 Ruggeri, caracterized by stunting, black discoloratìon of the wood and gum inclusions of xylem vessels, has been detected in a Sicilian nursery. A species of fungus, namely C. obtusisporium WOLLENW., has been isolated from the affected tissues. By artificial inoculations carried out on cuttings of the same rootstock, the isolate of C. obtusisporium has induced the syndrome observed in naturally occurring infections. The causal agent has been reisolated on an artificial medium from such affected vines. C. obtusisporium, apparently not yet reported on Vitis, seems to be the causal agent of the decline phenomena observed in the nursery.Â
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