280 research outputs found
ANÁLISE GEOMORFOLOGICA PRELIMINAR DO CORRÉGO DO CERRADO NO MUNICÍPIO DE CANÁPOLIS/MG
Historicamente rios e cidades estiveram intrinsecamente ligados, foi através dos rios que impérios se desenvolveram. Entender a dinâmica do relevo e dos rios é importante para compreender os problemas ambientais e sociais, já que o relevo é fator preponderante para o plantio e/ou povoamento. Neste contexto, o presente trabalho tem por objetivo fazer um levantamento preliminar da geomorfologia do Córrego do Cerrado que drena o município de Canápolis/MG, por meio de revisões bibliográfica e campo
From elongated spanning trees to vicious random walks
Given a spanning forest on a large square lattice, we consider by
combinatorial methods a correlation function of paths ( is odd) along
branches of trees or, equivalently, loop--erased random walks. Starting and
ending points of the paths are grouped in a fashion a --leg watermelon. For
large distance between groups of starting and ending points, the ratio of
the number of watermelon configurations to the total number of spanning trees
behaves as with . Considering the spanning
forest stretched along the meridian of this watermelon, we see that the
two--dimensional --leg loop--erased watermelon exponent is converting
into the scaling exponent for the reunion probability (at a given point) of
(1+1)--dimensional vicious walkers, . Also, we express the
conjectures about the possible relation to integrable systems.Comment: 27 pages, 6 figure
Gauge/Gravity Correspondence from Open/Closed String Duality
We compute the annulus diagram corresponding to the interaction of a
fractional D3 brane with a gauge field on its world-volume and a stack of N
fractional D3 branes on the orbifolds C^2 /Z_2 and C^3/Z_2 x Z_2. We show that
its logarithmic divergence can be equivalently understood as due either to
massless open string states circulating in the loop or to massless closed
string states exchanged between two boundary states. This follows from the fact
that, under open/closed string duality, massless states in the open and closed
string channels are matched into each other without mixing with massive states.
This explains why the perturbative properties of many gauge theories living on
the worldvolume of less supersymmetric and nonconformal branes have been
recently obtained from their corresponding supergravity solution.Comment: LaTeX, 28 page
Stochastic attractors for shell phenomenological models of turbulence
Recently, it has been proposed that the Navier-Stokes equations and a
relevant linear advection model have the same long-time statistical properties,
in particular, they have the same scaling exponents of their structure
functions. This assertion has been investigate rigorously in the context of
certain nonlinear deterministic phenomenological shell model, the Sabra shell
model, of turbulence and its corresponding linear advection counterpart model.
This relationship has been established through a "homotopy-like" coefficient
which bridges continuously between the two systems. That is, for
one obtains the full nonlinear model, and the corresponding linear
advection model is achieved for . In this paper, we investigate the
validity of this assertion for certain stochastic phenomenological shell models
of turbulence driven by an additive noise. We prove the continuous dependence
of the solutions with respect to the parameter . Moreover, we show the
existence of a finite-dimensional random attractor for each value of
and establish the upper semicontinuity property of this random attractors, with
respect to the parameter . This property is proved by a pathwise
argument. Our study aims toward the development of basic results and techniques
that may contribute to the understanding of the relation between the long-time
statistical properties of the nonlinear and linear models
A multi-omic single-cell landscape of human gynecologic malignancies
Deconvolution of regulatory mechanisms that drive transcriptional programs in cancer cells is key to understanding tumor biology. Herein, we present matched transcriptome (scRNA-seq) and chromatin accessibility (scATAC-seq) profiles at single-cell resolution from human ovarian and endometrial tumors processed immediately following surgical resection. This dataset reveals the complex cellular heterogeneity of these tumors and enabled us to quantitatively link variation in chromatin accessibility to gene expression. We show that malignant cells acquire previously unannotated regulatory elements to drive hallmark cancer pathways. Moreover, malignant cells from within the same patients show substantial variation in chromatin accessibility linked to transcriptional output, highlighting the importance of intratumoral heterogeneity. Finally, we infer the malignant cell type-specific activity of transcription factors. By defining the regulatory logic of cancer cells, this work reveals an important reliance on oncogenic regulatory elements and highlights the ability of matched scRNA-seq/scATAC-seq to uncover clinically relevant mechanisms of tumorigenesis in gynecologic cancers
A percepção do usuário sobre a abordagem de uma equipe de residentes multiprofissionais
Diet-dependent acid load and type 2 diabetes: pooled results from three prospective cohort studie
Aims/hypothesis: Studies suggest a potential link between low-grade metabolic acidosis and type 2 diabetes. A western dietary pattern increases daily acid load but the association between diet-dependent acid load and type 2 diabetes is still unclear. This study aimed to assess whether diet-dependent acid load is associated with the risk of type 2 diabetes. Methods: We examined the association between energy-adjusted net endogenous acid production (NEAP), potential renal acid load (PRAL) and animal protein-to-potassium ratio (A:P) on incident type 2 diabetes in 67,433 women from the Nurses’ Health Study, 84,310 women from the Nurses’ Health Study II and 35,743 men from the Health Professionals’ Follow-up Study who were free from type 2 diabetes, cardiovascular disease and cancer at baseline. Study-specific HRs were estimated using Cox proportional hazards models with time-varying covariates and were pooled using a random effects meta-analysis. Results: We documented 15,305 cases of type 2 diabetes during 4,025,131 person-years of follow-up. After adjustment for diabetes risk factors, dietary NEAP, PRAL and A:P were positively associated with type 2 diabetes (pooled HR [95% CI] for highest (Q5) vs lowest quintile (Q1): 1.29 [1.22, 1.37], ptrend <0.0001; 1.29 [1.22, 1.36], ptrend <0.0001 and 1.32 [1.24, 1.40], ptrend <0.0001 for NEAP, PRAL and A:P, respectively). These results were not fully explained by other dietary factors including glycaemic load and dietary quality (HR [95% CI] for Q5 vs Q1: 1.21 [1.09, 1.33], ptrend <0.0001; 1.19 [1.08, 1.30] and 1.26 [1.17, 1.36], ptrend <0.0001 for NEAP, PRAL and A:P, respectively). Conclusions/interpretation: This study suggests that higher diet-dependent acid load is associated with an increased risk of type 2 diabetes. This association is not fully explained by diabetes risk factors and overall diet quality
Total Cross Section Measurements with pi-, Sigma- and Protons on Nuclei and Nucleons around 600 GeV/c
Total cross sections for Sigma- and pi- on beryllium, carbon, polyethylene
and copper as well as total cross sections for protons on beryllium and carbon
have been measured in a broad momentum range around 600GeV/c. These
measurements were performed with a transmission technique adapted to the SELEX
hyperon-beam experiment at Fermilab. We report on results obtained for
hadron-nucleus cross sections and on results for sigma_tot(Sigma- N) and
sigma_tot(pi- N), which were deduced from nuclear cross sections.Comment: 42 pages, submitted to Nucl.Phys.
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