534 research outputs found
Responsabilidad por los daños causados a terceros en la superficie por el ruido y el estampido sónico
Characterization of Scattered Waves from Fractures by Estimating the Transfer Function Between Reflected Events Above and Below Each Interval
It is important to be able to detect and characterize naturally occurring fractures in reservoirs using surface seismic
reflection data. 3D finite difference elastic modeling is used to create simulated surface seismic data over a three layer model and a
five layer model. The elastic properties in the reservoir layer of each model are varied to simulate different amounts of vertical parallel
fracturing. The presence of the fractures induces ringing wave trains primarily at times later than the bottom reservoir reflection.
These ringy or scattered wave trains appear coherent on the seismograms recorded parallel to the fracture direction. While there are
many scattered events on the seismograms recorded perpendicular to the direction of the fractures, these events appear to generally
stack out during conventional processing.
A method of characterizing and detecting scattering in intervals is developed by deconvolution to give an interval transfer
function. The method is simple for the case of two isolated reflections, one from the top of the reservoir and the other from the bottom
of the reservoir. The transfer function is computed using the top reflection as the input and the bottom reflection as the output. The
transfer function then characterizes the effect of the scattering layer. A simple pulse shape indicates no scattering. A long ringy
transfer function captures the scattering within the reservoir interval. When analyzing field data, it is rarely possible to isolate
reflections. Therefore, an adaptation of the method is developed using autocorrelations of the wave trains above (as input) and below
(as output) the interval of interest for the deconvolution process. The presence of fractures should be detectable from observed ringy
transfer functions computed for each time interval. The fracture direction should be identifiable from azimuthal variations – there
should be more ringiness in the direction parallel to fracturing. The method applied to ocean bottom cable field data at 4 locations
show strong temporal and azimuthal variations of the transfer function which may be correlated to the known geology.Massachusetts Institute of Technology. Earth Resources LaboratoryUnited States. Dept. of Energy (Grant DE-FC26-02NT15346)Eni S.p.A. (Firm
Fracture Density Estimation Using Spectral Analysis of Reservoir Reflections: A Numerical Modeling Approach
We use a 3-D finite difference numerical model to generate synthetic seismograms from a simple fractured reservoir
containing evenly spaced, discrete, vertical fractures. The fractures are represented using a single column of
anisotropic grid points. Analysis of seismic amplitudes and spectral characteristics were carried out on the top and
base reservoir reflections as well as scattered wave coda for models with fracture spacing ranging from 0.01 to 0.1
fractures/m. Results show that the bulk scattered wave energy contained in a common shot gather increases greatly
when the fracture spacing is greater than about 1/4 wavelength. Wavenumber spectra for integrated amplitude
versus offset from a time window containing the base reservoir reflector show spectral peaks corresponding to the
fracture spacing.United States. Dept. of Energy (Grant DE-FC26-02NT15346)Massachusetts Institute of Technology. Earth Resources LaboratoryEni S.p.A. (Firm
Spatial Orientation And Distribution Of Reservoir Fractures From Scattered Seismic Energy
Shortened title: Fracture characterization from coda wavesWe present the details of a new method for determining the reflection and scattering characteristics of seismic energy from subsurface fractured formations. The method is based upon observations we have made from 3D finite difference modeling of the reflected and scattered seismic energy over discrete systems of vertical fractures. Regularly spaced, discrete vertical fractures impart a ringing coda type signature to any seismic energy which is transmitted through or reflected off of them. This signature varies in amplitude and coherence as a function of several parameters including: 1) the difference in angle between the orientation of the fractures and the acquisition direction, 2) the fracture spacing, 3) the wavelength of the illuminating seismic energy, and 4) the compliance, or stiffness, of the fractures. This coda energy is the most coherent when the acquisition direction is parallel to the strike of the fractures. It has the largest amplitude when the seismic wavelengths are tuned to the fracture spacing, and when the fractures have low stiffness. Our method uses surface seismic reflection traces to derive a transfer function which quantifies the change in an apparent source wavelet before and after propagating through a fractured interval. The transfer function for an interval with no or low amounts of scattering will be more spike-like and temporally compact. The transfer function for an interval with high scattering will ring and be less temporally compact. When a 3D survey is acquired with a full range of azimuths, the variation in the derived transfer functions allows us to identify subsurface areas with high fracturing and determine the strike of those fractures. We calibrated the method with model data and then applied it to the Emilio field with a fractured reservoir giving results which agree with known field measurements and previously published fracture orientations derived from PS anisotropy.Eni S.p.A. (Firm)United States. Dept. of Energy (Grant number DE-FC26-02NT15346)Massachusetts Institute of Technology. Earth Resources Laborator
Patient and disease pre-operative factors influencing surgical procedure choice for breast cancer treatment
Background/Objective: To address disparities of care in breast cancer treatment, it is important to understand pre‐operative factors that could affect the surgical decision‐making process.
Methods: This prospective cohort study evaluates patient‐reported outcomes in women undergoing breast cancer treatment at a metropolitan health care system. Each new breast cancer case undergoes tumor board discussion, and patients have same‐day consultations with various specialties. Based on their procedure choice, women choose to complete pre‐ and post‐operative Breast‐Q© Breast‐ conserving Surgery (BCS), Mastectomy (M), or Reconstruction ® modules and demographic surveys. Individual effects of pre‐operative factors on procedure choice were assessed using ANOVA for continuous variables and chi‐squared for categorical. Significant factors (p≤0.05) were added to a multinomial logistic regression model.
Results: A total of 375 women completed pre‐operative surveys (BCS=244, M=39, BR=92). Compared to BR, those chose BCS were older (RRR=1.094, p\u3c0.001) with larger BMIs (RRR=1.094, p=0.001), without a history of breast cancer (RRR=0.130 (yes vs. no), p=0.016), and Stage I disease (RRR=4.920, p\u3c0.001). Women making more than $200K (RRR=4.56x105 (vs. 35K), p\u3c0.0001) were also more likely to undergo BR. Compared to BCS, women undergoing neoadjuvant chemotherapy (RRR=3.591, p=0.047) and Stage II disease (RRR=4.238, p=0.040) were more likely to undergo mastectomy alone, whereas race, education, employment, and most incomes did not correlate with procedure choice.
Conclusions: Our data suggest that racial and socioeconomic disparities in procedure type can be addressed by presenting equally effective surgical strategies to all patients in a multidisciplinary model that allows patients to interact with plastic surgeons, radiation oncologists, and surgical and medical oncologists
Patient factors that affect pre-operative patient-reported outcomes in women undergoing breast cancer surgery
Background/Objective: Understanding the impact of patient, disease, and treatment factors on pre‐ operative patient reported outcomes (PROs) is important to guide surgical decision‐making with breast cancer.
Methods: This prospective cohort study evaluates PROs in women undergoing breast cancer treatment at a metropolitan health care system. New cases undergo tumor board discussion and same‐day consultations with various specialties. Women choose to complete pre‐ and post‐operative Breast‐Q© Breast‐conserving surgery (BCS), mastectomy (M), or reconstruction ® modules and demographic surveys. Individual associations to pre‐operative Breast‐Q survey scores were assessed using linear regression models (1 for each Breast‐Q survey type). Variables significant for at least 1 survey were included in multiple linear regression models.
Results: A total of 375 women completed the pre‐operative surveys (BCS=244, M=39, BR=92). Procedure choice, laterality, race, marital status, employment, prior breast cancer, neoadjuvant chemotherapy, or history of radiation or chemotherapy did not impact PROs. Breast satisfaction decreased with higher BMI (est=‐0.367, p=0.045) and Stage II disease (est=‐11.011 (vs. Stage 0), p=0.008). Lower psychosocial score was associated with younger age (est=0.271, p=0.002), higher BMI (est=‐0.367, p=0.014), and income \u3c35k (est=0.218 (vs. 35k+, p=0.039). Sexual well‐being decreased with higher BMI (est=‐0.545, p=0.004) and income \u3c$35k (est=0.135 (vs. 35k+), p=0.016).
Conclusions: While factors such as age, BMI, and stage of disease are difficult to change prior to surgery, patients with lower income may need special interventions to assist them through the treatment process
Mammary molecular portraits reveal lineage-specific features and progenitor cell vulnerabilities.
The mammary epithelium depends on specific lineages and their stem and progenitor function to accommodate hormone-triggered physiological demands in the adult female. Perturbations of these lineages underpin breast cancer risk, yet our understanding of normal mammary cell composition is incomplete. Here, we build a multimodal resource for the adult gland through comprehensive profiling of primary cell epigenomes, transcriptomes, and proteomes. We define systems-level relationships between chromatin-DNA-RNA-protein states, identify lineage-specific DNA methylation of transcription factor binding sites, and pinpoint proteins underlying progesterone responsiveness. Comparative proteomics of estrogen and progesterone receptor-positive and -negative cell populations, extensive target validation, and drug testing lead to discovery of stem and progenitor cell vulnerabilities. Top epigenetic drugs exert cytostatic effects; prevent adult mammary cell expansion, clonogenicity, and mammopoiesis; and deplete stem cell frequency. Select drugs also abrogate human breast progenitor cell activity in normal and high-risk patient samples. This integrative computational and functional study provides fundamental insight into mammary lineage and stem cell biology
A Brain-Computer Interface Based Attention Training Program for Treating Attention Deficit Hyperactivity Disorder
10.1371/journal.pone.0046692PLoS ONE710
Body composition among long distance runners
OBJECTIVE: The current study aimed to examine the body composition of adult male ultra-trail runners (UTR) according to their level
of participation (regional UTR-R, vs. national UTR-N).
METHODS: The sample was composed of 44 adult male UTR (aged 36.5±7.2 years; UTR-R: n=25; UTR-N: n=19). Body composition was
assessed by air displacement plethysmography, bioelectrical impedance, and dual-energy X-ray absorptiometry. In addition, the Food
Frequency Questionnaire (FFQ) was applied. A comparison between the groups was performed using independent samples t-test.
RESULTS: Significant differences between groups contrasting in the competitive level were found for chronological age (in years; UTRR:
38.8±8.2 vs. UTR-N: 33.5±4.1); body density (in L.kg-1; UTR-R: 1.062±0.015 vs. UTR-N: 1.074±0.009); and fat mass (in kg; UTR-R:
12.7±6.8 vs. UTR-N: 7.6±2.7).
CONCLUSION: UTR-N were younger, presented higher values for body density, and had less fat mass, although no significant differences
were found for fat-free mass. The current study evidenced the profile of long-distance runners and the need for weight management
programs to regulate body composition.OBJETIVO: O presente estudo objetivou examinar a composição corporal dos corredores de ultra-trail (UTR) e, adicionalmente, comparar
dois grupos de acordo com o nível de participação (Regional vs. Nacional, respectivamente UTR-R e UTR-N).
MÉTODOS: A amostra foi composta por 44 corredores adultos masculinos (36,5±7,2 anos de idade; UTR-R: n=25; UTR-N: n=19). A composição
corporal foi avaliada recorrendo à pletismografia de ar deslocado, bioimpedância elétrica e absorciometria de raios X de dupla
energia. Adicionalmente, foi utilizado o Questionário de Frequência Alimentar. A comparação entre grupos foi realizada com base na
prova t-student para amostras independentes.
RESULTADOS: Foram encontradas diferenças significativas por nível de competição para as seguintes variáveis dependentes: idade
cronológica (em anos; UTR-R: 38,8±8,2 vs. UTR-N: 33,5±4,1); densidade corporal (em kg/L; UTR-R: 1,062±0,015 L/kg vs. UTR-N:
1,074±0,009); massa gorda (em kg; UTR-R: 12,7±6,8 kg vs. UTR-N: 7,6±2,7).
CONCLUSÃO: Os UTR-N tendem a ser mais jovens e apresentam valores superiores de densidade corporal e, consequentemente, valores
menores de massa gorda, sendo a massa isenta de gordura semelhante entre os grupos. O presente estudo determinou o perfil dos
corredores adultos masculinos de longa distância (ultra-trail), realçando a importância de uma cuidadosa regulação da massa corporal
Dynamic T cell migration program provides resident memory within intestinal epithelium
Migration to intestinal mucosa putatively depends on local activation because gastrointestinal lymphoid tissue induces expression of intestinal homing molecules, whereas skin-draining lymph nodes do not. This paradigm is difficult to reconcile with reports of intestinal T cell responses after alternative routes of immunization. We reconcile this discrepancy by demonstrating that activation within spleen results in intermediate induction of homing potential to the intestinal mucosa. We further demonstrate that memory T cells within small intestine epithelium do not routinely recirculate with memory T cells in other tissues, and we provide evidence that homing is similarly dynamic in humans after subcutaneous live yellow fever vaccine immunization. These data explain why systemic immunization routes induce local cell-mediated immunity within the intestine and indicate that this tissue must be seeded with memory T cell precursors shortly after activation
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