Particulate-Matter Emission Estimates from Agricultural Spring-Tillage Operations Using LIDAR and Inverse Modeling

Particulate-matter (PM) emissions from a typical spring agricultural tillage sequence and a strip–till conservation tillage sequence in California’s San Joaquin Valley were estimated to calculate the emissions control efficiency (η) of the strip–till conservation management practice (CMP). Filter-based PM samplers, PM-calibrated optical particle counters (OPCs), and a PM-calibrated light detection and ranging (LIDAR) system were used to monitored upwind and downwind PM concentrations during May and June 2008. Emission rates were estimated through inverse modeling coupled with the filter and OPC measurements and through applying a mass balance to the PM concentrations derived from LIDAR data. Sampling irregularities and errors prevented the estimation of emissions from 42% of the sample periods based on filter samples. OPC and LIDAR datasets were sufficiently complete to estimate emissions and the strip–till CMP η, which were ∼90% for all size fractions in both datasets. Tillage time was also reduced by 84%. Calculated emissions for some operations were within the range of values found in published studies, while other estimates were significantly higher than literature values. The results demonstrate that both PM emissions and tillage time may be reduced by an order of magnitude through the use of a strip–till conservation tillage CMP when compared to spring tillage activities

Lidar Based Emissions Measurement at the Whole Facility Scale: Method and Error Analysis

Particulate emissions from agricultural sources vary from dust created by operations and animal movement to the fine secondary particulates generated from ammonia and other emitted gases. The development of reliable facility emission data using point sampling methods designed to characterize regional, well-mixed aerosols are challenged by changing wind directions, disrupted flow fields caused by structures, varied surface temperatures, and the episodic nature of the sources found at these facilities. We describe a three-wavelength lidar-based method, which, when added to a standard point sampler array, provides unambiguous measurement and characterization of the particulate emissions from agricultural production operations in near real time. Point-sampled data are used to provide the aerosol characterization needed for the particle concentration and size fraction calibration, while the lidar provides 3D mapping of particulate concentrations entering, around, and leaving the facility. Differences between downwind and upwind measurements provide an integrated aerosol concentration profile, which, when multiplied by the wind speed profile, produces the facility source flux. This approach assumes only conservation of mass, eliminating reliance on boundary layer theory. We describe the method, examine measurement error, and demonstrate the approach using data collected over a range of agricultural operations, including a swine grow-finish operation, an almond harvest, and a cotton gin emission study

Coupled Contagion Dynamics of Fear and Disease: Mathematical and Computational Explorations

Background: In classical mathematical epidemiology, individuals do not adapt their contact behavior during epidemics. They do not endogenously engage, for example, in social distancing based on fear. Yet, adaptive behavior is welldocumented in true epidemics. We explore the effect of including such behavior in models of epidemic dynamics. Methodology/Principal Findings: Using both nonlinear dynamical systems and agent-based computation, we model two interacting contagion processes: one of disease and one of fear of the disease. Individuals can ‘‘contract’ ’ fear through contact with individuals who are infected with the disease (the sick), infected with fear only (the scared), and infected with both fear and disease (the sick and scared). Scared individuals–whether sick or not–may remove themselves from circulation with some probability, which affects the contact dynamic, and thus the disease epidemic proper. If we allow individuals to recover from fear and return to circulation, the coupled dynamics become quite rich, and can include multiple waves of infection. We also study flight as a behavioral response. Conclusions/Significance: In a spatially extended setting, even relatively small levels of fear-inspired flight can have a dramatic impact on spatio-temporal epidemic dynamics. Self-isolation and spatial flight are only two of many possible actions that fear-infected individuals may take. Our main point is that behavioral adaptation of some sort must b

Risk and consequences of chemotherapy-induced thrombocytopenia in US clinical practice

Abstract Background Chemotherapy-induced thrombocytopenia (CIT) is a potentially serious complication that can lead to chemotherapy dose delays, dose reductions, or discontinuation, and increases the risk of serious bleeding events. The objectives of this study were to characterize the incidence, clinical consequences, and economic costs of CIT in current US clinical practice. Methods A retrospective cohort design and data from two US private healthcare claims repositories (01/2010–12/2016) were employed. Study population comprised adults who received selected myelosuppressive chemotherapy regimens for solid tumors or non-Hodgkin’s lymphoma. CIT was identified based on: diagnosis code for thrombocytopenia or bleeding; procedure code for platelet transfusion or bleeding control; or drug code for thrombopoietin-receptor agonist. Incidence of CIT was evaluated during the chemotherapy course (max. no. cycles = 8), and associated consequences and costs (2016US$) were evaluated during the cycle of the CIT episode. Results Among 215,508 cancer chemotherapy patients, CIT incidence during the course (mean no. cycles = 4.6) was 9.7$36,448 (32,332-41,331). Across cycles with CIT, mean cost of CIT-related care was $2179 (2029-2329), comprising$1024 (881–1167) for inpatient care and $1153 (1119-1187) for outpatient care. Conclusions In this retrospective evaluation of cancer chemotherapy patients, CIT incidence was high, especially among patients receiving gemcitabine-based regimens, and the costs of CIT-related care were substantial. Accordingly, interventions aimed at identifying and targeting high-risk patients for preventative measures may yield substantial clinical and economic benefits

Risk of chemotherapy-induced febrile neutropenia in patients with metastatic cancer not receiving granulocyte colony-stimulating factor prophylaxis in US clinical practice

OBJECTIVES: To evaluate the use of granulocyte colony-stimulating factor (G-CSF) prophylaxis in US patients with selected metastatic cancers and chemotherapy-induced febrile neutropenia (FN) incidence and associated outcomes among the subgroup who did not receive prophylaxis. METHODS: This retrospective cohort study was conducted at four US health systems and included adults with metastatic cancer (breast, colorectal, lung, non-Hodgkin lymphoma [NHL]) who received myelosuppressive chemotherapy (2009-2017). Patients were stratified by FN risk level based on risk factors and chemotherapy (low/unclassified risk, intermediate risk without any risk factors, intermediate risk with ≥ 1 risk factor [IR + 1], high risk [HR]). G-CSF use was evaluated among all patients stratified by FN risk, and FN/FN-related outcomes were evaluated among patients who did not receive first-cycle G-CSF prophylaxis. RESULTS: Among 1457 metastatic cancer patients, 20.5% and 28.1% were classified as HR and IR + 1, respectively. First-cycle G-CSF prophylaxis use was 48.5% among HR patients and 13.9% among IR + 1 patients. In the subgroup not receiving first-cycle G-CSF prophylaxis, FN incidence in cycle 1 was 7.8% for HR patients and 4.8% for IR + 1 patients; during the course, corresponding values were 16.9% and 15.9%. Most (\u3e 90%) FN episodes required hospitalization, and mortality risk ranged from 7.1 to 26.9% across subgroups. CONCLUSION: In this retrospective study, the majority of metastatic cancer chemotherapy patients for whom G-CSF prophylaxis is recommended did not receive it; FN incidence in this subgroup was notably high. Patients with elevated FN risk should be carefully identified and managed to ensure appropriate use of supportive care