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1.
Sci Rep ; 14(1): 13841, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38879658

RESUMEN

Floods affect communities and ecosystems worldwide, emphasizing the importance of identifying their precursors and enhancing resilience to these events. Here, we calculated Antecedent Total Water Storage (ATWS) anomalies from the new 5-day (5D) Gravity Recovery and Climate Experiment (GRACE) and its Follow-On (GRACE-FO) satellite solutions to enhance the detection of pre-flood and active flood conditions and to map post-flood storage anomalies. The GRACE data were compared with ~ 3300 flood events reported by the Dartmouth Flood Observatory (2002-2021), revealing distinct ATWS precursor signals in 5D solutions, in contrast to the monthly solutions. Specifically, floods caused by saturation-excess runoff-triggered by persistent rainfall, monsoonal patterns, snowmelt, or rain-on-snow events-show detectable ATWS increases 15 to 50 days before and during floods, providing a valuable opportunity to improve flood monitoring. These 5D solutions also facilitate a more rapid mapping of post-flood storage changes to assess flood recovery from tropical cyclones and sub-monthly weather extremes. Our findings show the promising potential of 5D GRACE solutions, which are still in the development phase, for future integration into operational frameworks to enhance flood detection and recovery, facilitating the rapid analysis of storage changes relative to monthly solutions.

2.
Adv Radiat Oncol ; 7(6): 100859, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36420209

RESUMEN

Purpose: Hippocampal volume (HV) is an established predicting factor for neurocognitive function (NCF) in neurodegenerative disease. Whether the same phenomenon exists with hippocampal-avoidant whole brain radiation therapy is not known; therefore, we assessed the association of baseline HV with NCF among patients enrolled on RTOG 0933. Methods and Materials: Hippocampal volume and total brain volume were calculated from the radiation therapy plan. Hippocampal volume was correlated with baseline and 4-month NCF scores (Hopkins Verbal Learning Test-Revised [HVLT-R] Total Recall [TR], Immediate Recognition, and Delayed Recall [DR]) using Pearson correlation. Deterioration in NCF was defined per the primary endpoint of RTOG 0933(mean 4-month relative decline in HVLT-R DR). Comparisons between patients with deteriorated and nondeteriorated NCF were made using the Wilcoxon test. Results: Forty-two patients were evaluable. The median age was 56.5 years (range, 28-83 years), and 81% had a class II recursive partitioning analysis. The median total, right, and left HVs were 5.4 cm3 (range, 1.9-7.4 cm3), 2.8 cm3 (range, 0.9-4.0 cm3), and 2.7 cm3 (range, 1.0-3.7 cm3), respectively. The median total brain volume was 1343 cm3 (range, 1120.5-1738.8 cm3). For all measures of corrected HV, increasing HV was associated with higher baseline HVLT-R TR and DR scores (ρ: range, 0.35-0.40; P-value range, .009-.024) and 4-month TR and DR scores (ρ: range, 0.29-0.40; P-value range, .009-.04), with the exception of right HV and 4-month DR scores (ρ: 0.29; P = .059). There was no significant association between HV and NCF change between baseline and 4 months. Fourteen patients (33.3%) developed NCF deterioration per the primary endpoint of RTOG 0933. There was no significant difference in HV between patients with deteriorated and nondeteriorated NCF, although in all instances, patients with deteriorated NCF had numerically lower HV. Conclusions: Larger HV was positively associated with improved performance on baseline and 4-month HVLT-R TR and DR scores in patients with brain metastases undergoing hippocampal-avoidant whole brain radiation therapy but was not associated with a change in NCF.

3.
Sci Total Environ ; 803: 149810, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34492489

RESUMEN

Two-way feedbacks exist between water-stressed vegetation and agricultural drought. Previous studies have focused mainly on the responses of vegetation to agricultural droughts but rarely on those of agricultural droughts to vegetation. Based on a new drought index (AgDI) that incorporates dynamic climatic and vegetation information, this study evaluated the impacts of climate and vegetation variabilities on agricultural droughts in 20 catchments in southwestern China, a region frequently hit by droughts. Results showed that the drought-stressed vegetation tended to alleviate agricultural droughts, and the drought-alleviating ability of vegetation was affected by vegetation types and the magnitudes of the changes in climate. Compared to other types of vegetation, the natural forest generally has a greater ability to affect agricultural drought. Overall, the relative contribution (mean of 29.9 ± 24.6%) of changes in vegetation to agricultural drought was at least comparable to those of the changes in potential evapotranspiration (mean of 14.4 ± 12.7%). Results also showed that even though vegetation has the ability to alleviate agricultural droughts, the changes in agricultural droughts were still dominated by climate changes, especially precipitation (mean relative contribution of 55.7 ± 24.2%).


Asunto(s)
Sequías , Bosques , Agricultura , Cambio Climático , Agua
4.
Sci Total Environ ; 818: 151677, 2022 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-34793795

RESUMEN

The Gravity Recovery and Climate Experiment (GRACE) satellites provide a powerful tool for monitoring sediment mass change. However, signal leakage from nearby groundwater storage depletion in the North China Plain limits the potential capacity of GRACE to estimate sediment input from the Yellow River flows into the Bohai Sea. In the present work, we developed an improved approach based on forward modeling to reduce signal leakage from GRACE data and combined it with satellite altimetry to recover sediment load changes from 2003 to 2013 to the Bohai Sea. The total sediment input averaged 1.7 ± 0.8 Gt/yr, which agrees well with the estimate based on in-situ sediment data measured from the sediment cores (1.1 Gt/yr). Our method is also capable to describe sediment seasonal variations, with higher inputs in winter and spring, which confirm the output simulated by the sediment transportation model. We make presently tentative connections of seasonal variations to sediment resuspension driven by climatic monsoons contributed rough seas: although sediment load in rivers peaks in summer, low water discharge of the Yellow River leads to most of the sediment being deposited in a narrow area near the river mouth and not transported into the Bohai Sea; in winter and spring, huge waves provide favorable conditions for resuspension resulting in large amounts of sediment near the estuary being transported to the ocean along with northward waves. Moreover, our results indicate coastal erosion is also a nonnegligible resource of the sediment in the Bohai Sea. Comparing to the traditional approach, our study provides a new technological way to derive sediment in the Bohai Sea, which is capable of providing continuous measurements with improved timeliness at a lower cost.


Asunto(s)
Monitoreo del Ambiente , Contaminantes Químicos del Agua , China , Monitoreo del Ambiente/métodos , Estuarios , Sedimentos Geológicos , Océanos y Mares , Ríos , Contaminantes Químicos del Agua/análisis
5.
Environ Manage ; 66(3): 348-363, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32591935

RESUMEN

Projecting landscape impacts from energy development is essential to land management decisions. We forecast landscape alteration resulting from oil and gas well-pad construction across the economically important Permian Basin of Texas and New Mexico, USA, by projecting current landscape trends through 2050. We modeled three landscape-impact scenarios (low, medium, and high) using recent (2008-2017) trends in well-pad construction and energy production. The results of low-, medium-, and high-impact scenarios suggest that ~60,000, ~180,000, and ~430,000 new well pads could be constructed, potentially causing ~1000, ~2800, and ~6700 km2 of new direct landscape alteration. Almost two-thirds of all new well pads will be constructed within the geologic boundaries of the Delaware and Midland Basins. This translates into a 40, 120, and 300% increase in direct landscape alteration compared with direct alteration from existing well pads. We found that indirect effects (from edges) could increase by twofold, and that the ratio between indirect and direct alteration could decline by half as alteration intensifies and overlaps with existing alteration. The Chihuahuan Desert occupies the largest portion of the study area, and is projected to experience the largest area of alteration from future well-pad construction in the Permian Basin; the degree of direct alteration could increase by 70, 200, and 500% in this desert region, under low-, medium-, and high-impact scenarios. These scenarios can be used to design proactive conservation strategies to reduce landscape impacts from future oil and gas development.


Asunto(s)
Yacimiento de Petróleo y Gas , New Mexico , Texas
6.
Transl Lung Cancer Res ; 8(Suppl 2): S139-S146, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31673518

RESUMEN

The treatment paradigm of stage III, unresectable non-small cell lung cancer (NSCLC) has had few advancement since concurrent chemoradiotherapy was established as standard of care treatment. Despite modifications to radiotherapy, chemotherapy and surgical approaches, loco-regional and distant relapse remain high, which unfortunately has translated to poor survival outcomes. The PACIFIC study introduced immunotherapy to the domain of stage III NSCLC and has emerged as the fourth pillar in cancer treatment for these patients. The positive results of the study have excited both the radiation and medical oncology communities, demonstrating improvements in overall and progression-free survival (PFS). In this review, we discuss the details and impacts of the PACIFIC study, as well as the future implications for the treatment of stage III NSCLC.

7.
J Clin Oncol ; 37(15): 1316-1325, 2019 05 20.
Artículo en Inglés | MEDLINE | ID: mdl-30943123

RESUMEN

PURPOSE: Patients with centrally located early-stage non-small-cell lung cancer (NSCLC) are at a higher risk of toxicity from high-dose ablative radiotherapy. NRG Oncology/RTOG 0813 was a phase I/II study designed to determine the maximum tolerated dose (MTD), efficacy, and toxicity of stereotactic body radiotherapy (SBRT) for centrally located NSCLC. MATERIALS AND METHODS: Medically inoperable patients with biopsy-proven, positron emission tomography-staged T1 to 2 (≤ 5 cm) N0M0 centrally located NSCLC were accrued into a dose-escalating, five-fraction SBRT schedule that ranged from 10 to 12 Gy/fraction (fx) delivered over 1.5 to 2 weeks. Dose-limiting toxicity (DLT) was defined as any treatment-related grade 3 or worse predefined toxicity that occurred within the first year. MTD was defined as the SBRT dose at which the probability of DLT was closest to 20% without exceeding it. RESULTS: One hundred twenty patients were accrued between February 2009 and September 2013. Patients were elderly, there were slightly more females, and the majority had a performance status of 0 to 1. Most cancers were T1 (65%) and squamous cell (45%). Organs closest to planning target volume/most at risk were the main bronchus and large vessels. Median follow-up was 37.9 months. Five patients experienced DLTs; MTD was 12.0 Gy/fx, which had a probability of a DLT of 7.2% (95% CI, 2.8% to 14.5%). Two-year rates for the 71 evaluable patients in the 11.5 and 12.0 Gy/fx cohorts were local control, 89.4% (90% CI, 81.6% to 97.4%) and 87.9% (90% CI, 78.8% to 97.0%); overall survival, 67.9% (95% CI, 50.4% to 80.3%) and 72.7% (95% CI, 54.1% to 84.8%); and progression-free survival, 52.2% (95% CI, 35.3% to 66.6%) and 54.5% (95% CI, 36.3% to 69.6%), respectively. CONCLUSION: The MTD for this study was 12.0 Gy/fx; it was associated with 7.2% DLTs and high rates of tumor control. Outcomes in this medically inoperable group of mostly elderly patients with comorbidities were comparable with that of patients with peripheral early-stage tumors.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Neoplasias Pulmonares/radioterapia , Radiocirugia/métodos , Anciano , Anciano de 80 o más Años , Fraccionamiento de la Dosis de Radiación , Relación Dosis-Respuesta en la Radiación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radiocirugia/efectos adversos , Resultado del Tratamiento
8.
Proc Natl Acad Sci U S A ; 115(6): E1080-E1089, 2018 02 06.
Artículo en Inglés | MEDLINE | ID: mdl-29358394

RESUMEN

Assessing reliability of global models is critical because of increasing reliance on these models to address past and projected future climate and human stresses on global water resources. Here, we evaluate model reliability based on a comprehensive comparison of decadal trends (2002-2014) in land water storage from seven global models (WGHM, PCR-GLOBWB, GLDAS NOAH, MOSAIC, VIC, CLM, and CLSM) to trends from three Gravity Recovery and Climate Experiment (GRACE) satellite solutions in 186 river basins (∼60% of global land area). Medians of modeled basin water storage trends greatly underestimate GRACE-derived large decreasing (≤-0.5 km3/y) and increasing (≥0.5 km3/y) trends. Decreasing trends from GRACE are mostly related to human use (irrigation) and climate variations, whereas increasing trends reflect climate variations. For example, in the Amazon, GRACE estimates a large increasing trend of ∼43 km3/y, whereas most models estimate decreasing trends (-71 to 11 km3/y). Land water storage trends, summed over all basins, are positive for GRACE (∼71-82 km3/y) but negative for models (-450 to -12 km3/y), contributing opposing trends to global mean sea level change. Impacts of climate forcing on decadal land water storage trends exceed those of modeled human intervention by about a factor of 2. The model-GRACE comparison highlights potential areas of future model development, particularly simulated water storage. The inability of models to capture large decadal water storage trends based on GRACE indicates that model projections of climate and human-induced water storage changes may be underestimated.

9.
J Thorac Oncol ; 12(10): 1561-1570, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28648948

RESUMEN

INTRODUCTION: NRG Oncology RTOG 0937 is a randomized phase II trial evaluating 1-year overall survival (OS) with prophylactic cranial irradiation (PCI) or PCI plus consolidative radiation therapy (PCI+cRT) to intrathoracic disease and extracranial metastases for extensive-disease SCLC. METHODS: Patients with one to four extracranial metastases were eligible after a complete response or partial response to chemotherapy. Randomization was to PCI or PCI+cRT to the thorax and metastases. Original stratification included partial response versus complete response after chemotherapy and one versus two to four metastases; age younger than 65 years versus 65 years or older was added after an observed imbalance. PCI consisted of 25 Gy in 10 fractions. cRT consisted of 45 Gy in 15 fractions. To detect an improvement in OS from 30% to 45% with a 34% hazard reduction (hazard ratio = 0.66) under a 0.1 type 1 error (one sided) and 80% power, 154 patients were required. RESULTS: A total of 97 patients were randomized between March 2010 and February 2015. Eleven patients were ineligible (nine in the PCI group and two in the PCI+cRT group), leaving 42 randomized to receive PCI and 44 to receive PCI+cRT. At planned interim analysis, the study crossed the futility boundary for OS and was closed before meeting the accrual target. Median follow-up was 9 months. The 1-year OS was not different between the groups: 60.1% (95% confidence interval [CI]: 41.2-74.7) for PCI and 50.8% (95% CI: 34.0-65.3) for PCI+cRT (p = 0.21). The 3- and 12-month rates of progression were 53.3% and 79.6% for PCI and 14.5% and 75% for PCI+cRT, respectively. Time to progression favored PCI+cRT (hazard ratio = 0.53, 95% CI: 0.32-0.87, p = 0.01). One patient in each arm had grade 4 therapy-related toxicity and one had grade 5 therapy-related pneumonitis with PCI+cRT. CONCLUSIONS: OS exceeded predictions for both arms. cRT delayed progression but did not improve 1-year OS.


Asunto(s)
Irradiación Craneana/métodos , Neoplasias Pulmonares/complicaciones , Carcinoma Pulmonar de Células Pequeñas/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias Encefálicas/secundario , Femenino , Humanos , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Carcinoma Pulmonar de Células Pequeñas/mortalidad , Carcinoma Pulmonar de Células Pequeñas/patología , Tasa de Supervivencia
10.
Sci Rep ; 6: 24768, 2016 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-27094448

RESUMEN

We study the convection and mixing of CO2 in a brine aquifer, where the spread of dissolved CO2 is enhanced because of geochemical reactions with the host formations (calcite and dolomite), in addition to the extensively studied, buoyancy-driven mixing. The nonlinear convection is investigated under the assumptions of instantaneous chemical equilibrium, and that the dissipation of carbonate rocks solely depends on flow and transport and chemical speciation depends only on the equilibrium thermodynamics of the chemical system. The extent of convection is quantified in term of the CO2 saturation volume of the storage formation. Our results suggest that the density increase of resident species causes significant enhancement in CO2 dissolution, although no significant porosity and permeability alterations are observed. Early saturation of the reservoir can have negative impact on CO2 sequestration.

11.
J Environ Manage ; 165: 188-198, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26433360

RESUMEN

This work presents an optimization framework for evaluating different wastewater treatment/disposal options for water management during hydraulic fracturing (HF) operations. This framework takes into account both cost-effectiveness and system uncertainty. HF has enabled rapid development of shale gas resources. However, wastewater management has been one of the most contentious and widely publicized issues in shale gas production. The flowback and produced water (known as FP water) generated by HF may pose a serious risk to the surrounding environment and public health because this wastewater usually contains many toxic chemicals and high levels of total dissolved solids (TDS). Various treatment/disposal options are available for FP water management, such as underground injection, hazardous wastewater treatment plants, and/or reuse. In order to cost-effectively plan FP water management practices, including allocating FP water to different options and planning treatment facility capacity expansion, an optimization model named UO-FPW is developed in this study. The UO-FPW model can handle the uncertain information expressed in the form of fuzzy membership functions and probability density functions in the modeling parameters. The UO-FPW model is applied to a representative hypothetical case study to demonstrate its applicability in practice. The modeling results reflect the tradeoffs between economic objective (i.e., minimizing total-system cost) and system reliability (i.e., risk of violating fuzzy and/or random constraints, and meeting FP water treatment/disposal requirements). Using the developed optimization model, decision makers can make and adjust appropriate FP water management strategies through refining the values of feasibility degrees for fuzzy constraints and the probability levels for random constraints if the solutions are not satisfactory. The optimization model can be easily integrated into decision support systems for shale oil/gas lifecycle management.


Asunto(s)
Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Contaminación del Agua/análisis , Monitoreo del Ambiente , Fracking Hidráulico , Modelos Teóricos , Reproducibilidad de los Resultados , Incertidumbre , Agua , Contaminantes Químicos del Agua/química , Purificación del Agua/economía , Purificación del Agua/métodos
12.
Int J Radiat Oncol Biol Phys ; 86(4): 656-64, 2013 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-23597420

RESUMEN

PURPOSE: To assess the impact of prophylactic cranial irradiation (PCI) on self-reported cognitive functioning (SRCF), a functional scale on the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ-C30). METHODS AND MATERIALS: Radiation Therapy Oncology Group (RTOG) protocol 0214 randomized patients with locally advanced non-small cell lung cancer to PCI or observation; RTOG 0212 randomized patients with limited-disease small cell lung cancer to high- or standard-dose PCI. In both trials, Hopkins Verbal Learning Test (HVLT)-Recall and -Delayed Recall and SRCF were assessed at baseline (after locoregional therapy but before PCI or observation) and at 6 and 12 months. Patients developing brain relapse before follow-up evaluation were excluded. Decline was defined using the reliable change index method and correlated with receipt of PCI versus observation using logistic regression modeling. Fisher's exact test correlated decline in SRCF with HVLT decline. RESULTS: Of the eligible patients pooled from RTOG 0212 and RTOG 0214, 410 (93%) receiving PCI and 173 (96%) undergoing observation completed baseline HVLT or EORTC QLQ-C30 testing and were included in this analysis. Prophylactic cranial irradiation was associated with a higher risk of decline in SRCF at 6 months (odds ratio 3.60, 95% confidence interval 2.34-6.37, P<.0001) and 12 months (odds ratio 3.44, 95% confidence interval 1.84-6.44, P<.0001). Decline on HVLT-Recall at 6 and 12 months was also associated with PCI (P=.002 and P=.002, respectively) but was not closely correlated with decline in SRCF at the same time points (P=.05 and P=.86, respectively). CONCLUSIONS: In lung cancer patients who do not develop brain relapse, PCI is associated with decline in HVLT-tested and self-reported cognitive functioning. Decline in HVLT and decline in SRCF are not closely correlated, suggesting that they may represent distinct elements of the cognitive spectrum.


Asunto(s)
Neoplasias Encefálicas/prevención & control , Carcinoma de Pulmón de Células no Pequeñas/prevención & control , Cognición/efectos de la radiación , Irradiación Craneana/efectos adversos , Neoplasias Pulmonares , Memoria a Corto Plazo/efectos de la radiación , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/efectos de la radiación , Neoplasias Encefálicas/secundario , Carcinoma de Pulmón de Células no Pequeñas/secundario , Trastornos del Conocimiento/etiología , Intervalos de Confianza , Irradiación Craneana/métodos , Femenino , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Calidad de Vida , Autoinforme , Encuestas y Cuestionarios , Factores de Tiempo
13.
J Thorac Cardiovasc Surg ; 137(2): 441-447.e1, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19185167

RESUMEN

OBJECTIVE: We evaluated the outcome, long-term results, and factors affecting outcome of induction chemoradiotherapy followed by surgical resection for T4 non-small cell lung cancer invading the spine. METHODS: Retrospective analysis of 23 consecutive patients undergoing radical vertebral resection for non-small cell lung cancer invading the spine between 1996 and 2007 was performed. In most cases, induction chemoradiotherapy consisted of cisplatin and etoposide followed by 45 Gy of radiation. Surgical resection with vertebrectomy was performed en bloc in either a 1-stage or 2-stage operation. Survival was estimated by Kaplan-Meier techniques. The log-rank comparison was used to compare groups. RESULTS: There were 13 men and 10 women with a median age of 61 years (range 32-75). Twenty-two patients had induction chemoradiotherapy and 1 had induction chemotherapy alone. Vertebral resections included 6 total vertebrectomies, 15 hemivertebrectomies, and 2 partial vertebrectomies. Complete resection was achieved in 19 (83%) patients. Two (8.7%) patients died postoperatively. Pathologic complete response was observed in 10 (43%) patients. The 3-year survival was 58% (median follow-up, 34 months). Patients who achieved pathologic complete response or near complete response (viable tumor cells < 1%) demonstrated significantly better survival than those who did not (3-year survival, 92% vs 20%; P = .006). CONCLUSION: Highly selected patients with lung cancer invading the spine can potentially be cured with induction chemoradiation therapy followed by radical en bloc resection of the tumor. A multidisciplinary operative strategy allows a significant chance of achieving complete resection in patients requiring multilevel hemivertebrectomy or total vertebrectomy and an appreciable cure rate.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/cirugía , Neoplasias Pulmonares/cirugía , Terapia Neoadyuvante/métodos , Neoplasias de la Columna Vertebral/patología , Adulto , Anciano , Antineoplásicos/administración & dosificación , Carcinoma de Pulmón de Células no Pequeñas/patología , Quimioterapia Adyuvante , Cisplatino/administración & dosificación , Etopósido/administración & dosificación , Femenino , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Radiografía , Dosificación Radioterapéutica , Radioterapia Adyuvante , Estudios Retrospectivos , Neoplasias de la Columna Vertebral/diagnóstico por imagen , Neoplasias de la Columna Vertebral/cirugía
14.
Ground Water ; 46(4): 638-41, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18331330

RESUMEN

Model-based contaminant source identification plays an important role in effective site remediation. In this article, a contaminant source identification toolbox (CONSID) is introduced as a framework for solving contaminant source identification problems. It is known that the presence of various types of model uncertainties can severely undermine the performance of many existing source estimators. The current version of CONSID consists of two robust estimators for recovering source release histories under model uncertainty; one was developed in the deterministic framework and the other in the stochastic framework. To use the robust estimators provided in CONSID, the user is required to have only modest prior knowledge about the model uncertainty and be able to estimate the bound of model deviations resulting from the uncertainty. The toolbox is designed so that other source estimators can be added easily. A step-by-step guidance for using CONSID is described and an example is provided.


Asunto(s)
Contaminantes del Agua/análisis , Modelos Teóricos
15.
J Contam Hydrol ; 88(3-4): 181-96, 2006 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-16889871

RESUMEN

Contamination source identification is a crucial step in environmental remediation. The exact contaminant source locations and release histories are often unknown due to lack of records and therefore must be identified through inversion. Coupled source location and release history identification is a complex nonlinear optimization problem. Existing strategies for contaminant source identification have important practical limitations. In many studies, analytical solutions for point sources are used; the problem is often formulated and solved via nonlinear optimization; and model uncertainty is seldom considered. In practice, model uncertainty can be significant because of the uncertainty in model structure and parameters, and the error in numerical solutions. An inaccurate model can lead to erroneous inversion of contaminant sources. In this work, a constrained robust least squares (CRLS) estimator is combined with a branch-and-bound global optimization solver for iteratively identifying source release histories and source locations. CRLS is used for source release history recovery and the global optimization solver is used for location search. CRLS is a robust estimator that was developed to incorporate directly a modeler's prior knowledge of model uncertainty and measurement error. The robustness of CRLS is essential for systems that are ill-conditioned. Because of this decoupling, the total solution time can be reduced significantly. Our numerical experiments show that the combination of CRLS with the global optimization solver achieved better performance than the combination of a non-robust estimator, i.e., the nonnegative least squares (NNLS) method, with the same solver.


Asunto(s)
Modelos Teóricos , Contaminantes Químicos del Agua/análisis , Contaminación Química del Agua , Restauración y Remediación Ambiental , Análisis de los Mínimos Cuadrados
16.
Lung Cancer ; 49(1): 109-15, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15949596

RESUMEN

OBJECTIVE: The radical treatment of locally advanced non-small cell lung cancer (LA-NSCLC) currently involves combined modality therapy (CMT) with the use of chemotherapy in addition to radiation therapy and/or surgery. Chemotherapy has been shown to improve survival, but does not alter brain relapse. We reviewed the outcomes of Stage IIIA and IIIB LA-NSCLC patients treated with CMT at our institution. We assessed the incidence of brain metastases and the management and outcome of these patients. METHODS: Using our radiation-planning database (RSTS), we identified 230 consecutive patients from the years 1999 and 2000 who received radical radiation therapy to the lung. Extracting data from the chart, we identified 83 patients who were treated radically with chemotherapy, radiation and possibly surgery. These patients form the basis of this study. RESULTS: At 2 years, the actuarial rates for any brain failure, first failure in the brain and sole failure in the brain were 34.2%, 24.6% and 11.0%, respectively. Age was the only factor among sex, histology, stage, weight loss and the timing of chemotherapy and radiation that predicted for an increased risk of first failure in the brain. Patients less than age 60 had a risk of 25.6% versus 11.4% for those greater than 60 (p = 0.022). Among the patients who failed first in the brain, those who had aggressive management of their brain metastases with surgical resection in addition to whole brain radiotherapy had a median survival of 26.3 months compared with 3.3 months for those treated with palliative whole brain radiotherapy alone. CONCLUSION: Brain metastases are common in patients with LA-NSCLC treated with CMT. These patients may benefit from either prophylactic cranial irradiation or early detection and aggressive treatment of brain metastases.


Asunto(s)
Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundario , Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Carcinoma de Pulmón de Células no Pequeñas/secundario , Irradiación Craneana , Neoplasias Pulmonares/patología , Anciano , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/epidemiología , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico , Carcinoma de Pulmón de Células no Pequeñas/epidemiología , Terapia Combinada , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Estudios Retrospectivos , Factores de Riesgo
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