Evaluation of a soil incubation method to characterize nitrogen release patterns of slow- and controlled-release fertilizers.

Several technologies have been proposed to characterize the nutrient release patterns of slow-release fertilizers (SRF) and controlled-release fertilizers (CRF) during the last few decades. These technologies have been developed mainly by manufacturers, and are product-specific, based on the regulation and analysis of each SRF and CRF product. Despite previous efforts to characterize SRF and CRF materials, no standardized, validated method exists to assess their nutrient release patterns. However, the increased production and distribution of these materials in specialty and nonspecialty markets requires an appropriate method to verify product claims and material performance. A soil incubation column leaching procedure was evaluated to determine its suitability as a standard method to estimate nitrogen (N) release patterns of SRFs and CRFs during 180 days. The influence of three soil/sand ratios, three incubation temperatures, and four soils on method behavior was assessed using five SRFs and three CRFs. In general, the highest soil/sand ratio increased the N release rate of all materials, but this effect was more marked for the SRFs. Temperature had the greatest influence on N release rates. For CRFs, the initial N release rates and the percentage N released/day increased as temperature increased. For SRFs, raising the temperature from 25 to 35 degreesC increased initial N release rate and the total cumulative N released, and almost doubled the percentage released/day. The percentage N released/day from all products generally increased as the texture of the soil changed from sandy to loamy (lowa>California>Pennsylvania>Florida). The soil incubation technique was demonstrated to be robust and reliable for characterizing N release patterns from SRFs and CRFs. The method was reproducible, and variations in soil/sand ratio, temperature, and soil had little effect on the results.

Optimization and validation of an accelerated laboratory extraction method to estimate nitrogen release patterns of slow- and controlled-release fertilizers.

Several technologies have been proposed to characterize the nutrient release and availability patterns of enhanced-efficiency fertilizers (EEFs), especially slow-release fertilizers (SRFs) and controlled-release fertilizers (CRFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product-specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize EEF materials, no validated method exists to assess their nutrient release patterns. However, the increased use of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. A series of experiments were conducted to evaluate the effect of temperature, fertilizer test portion size, and extraction time on the performance of a 74 h accelerated laboratory extraction method to measure SRF and CRF nutrient release profiles. Temperature was the only factor that influenced nutrient release rate, with a highly marked effect for phosphorus and to a lesser extent for nitrogen (N) and potassium. Based on the results, the optimal extraction temperature set was: Extraction No. 1-2:00 h at 25 degrees C; Extraction No. 2-2:00 h at 50 degrees C; Extraction No. 3-20:00 h at 55 degrees C; and Extraction No. 4-50:00 h at 60 degrees C. Ruggedness of the method was tested by evaluating the effect of small changes in seven selected factors on method behavior using a fractional multifactorial design. Overall, the method showed ruggedness for measuring N release rates of coated CRFs.

Statistical correlation of the soil incubation and the accelerated laboratory extraction methods to estimate nitrogen release rates of slow- and controlled-release fertilizers.

Several technologies have been proposed to characterize the nutrient release patterns of enhanced-efficiency fertilizers (EEFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product-specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize nutrient release of slow-release fertilizer (SRF) and controlled-release fertilizer (CRF) materials, no official method exists to assess their nutrient release patterns. However, the increased production and distribution of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. Nonlinear regression was used to establish a correlation between the data generated from a 180-day soil incubation-column leaching procedure and 74 h accelerated lab extraction method, and to develop a model that can predict the 180-day nitrogen (N) release curve for a specific SRF and CRF product based on the data from the accelerated laboratory extraction method. Based on the R2 > 0.90 obtained for most materials, results indicated that the data generated from the 74 h accelerated lab extraction method could be used to predict N release from the selected materials during 180 days, including those fertilizers that require biological activity for N release.

Evaluation of commonly used methods for the analysis of acid-soluble phosphate in internationally traded inorganic fertilizers.

Several methodologies are used throughout the world to determine phosphate concentration (measured as PO4 and expressed as % P2O5) in fertilizers. Concentrated phosphate materials, including diammonium phosphate (DAP) and monoammonium phosphate (MAP), are traded in large volumes (millions of metric tons) internationally. The International Fertilizer Association (IFA) identified a need to assess the methods currently being used to measure the phosphate content for suitability (scope), accuracy, and repeatability. Even small discrepancies in the expressed P2O5 content can have a major financial impact on buyers and sellers as contracts are settled and import regulations are imposed. The IFA's Technical Committee selected a working group to address issues dealing with harmonization of fertilizer sampling and analytical methodologies. The working group identified phosphate content in DAP and MAP fertilizers as a major concern for commerce. The working group initiated a method screening and comparison project to assess method performance and to determine which methods, if any, could be considered best practice methods and, therefore, be deemed acceptable for use by the industry. In order to systematically review the acceptability of methods for consideration, the task force developed an assessment protocol outlined in a white paper involving three steps: (1) compile all known relevant methods practiced in global fertilizer trade, (2) review and evaluate methods based upon specific evaluation criteria, and (3) compare the methods that most closely fit the evaluation criteria by multilaboratory analysis of unknown materials for accuracy and repeatability. Six methods were evaluated for analysis of total phosphate in concentrated phosphate products. From these methods, four were determined to be acceptable as best practice methods. The study members proposed three of the methods, while a fourth method was commonly used among the participating laboratories. This publication is a summary of the method comparison process and statistical evaluation of analysis of total phosphate content in concentrated phosphate fertilizers.

Testing of commonly used mixing and sampling procedures to evaluate fertilizer blends prepared with matched and mismatched particle sizes.

Bulk blending of dry fertilizers is a common practice in the United States and around the world. This practice involves the mixing (either physically or volumetrically) of concentrated, high analysis raw materials. Blending is followed by bagging (for small volume application such as lawn and garden products), loading into truck transports, and spreading. The great majority of bulk blended products are not bagged but handled in bulk and transferred from the blender to a holding hopper. The product is then transferred to a transport vehicle, which may, or may not, also be a spreader. If the primary transport vehicle is not a spreader, then there is another transfer at the user site to a spreader for application. Segregation of materials that are mismatched due to size, density, or shape is an issue when attempting to effectively sample or evenly spread bulk blended products. This study, prepared in coordination with and supported by the Florida Department of Agriculture and Consumer Services and the Florida Fertilizer and Agrochemical Association, looks at the impact of varying particle size as it relates to blending, sampling, and application of bulk blends. The study addresses blends containing high ratios of N-P-K materials and varying (often small) quantities of the micronutrient Zn.

Promotion of walking for transportation: a report from the Walk to School day registry.

BACKGROUND: In the US, promoting active transportation to school has received increased attention as a means of encouraging physical activity and preventing obesity among youth. However, little systematic evaluation of existing programs, such as Walk to School (WTS), has occurred. METHODS: WTS coordinators from across the US were surveyed (via web, mail, and telephone) about program activities, school and environmental characteristics, and perceived changes in children walking to school. As an exploratory aim, logistic regression analyses were used to examine program characteristics associated with perceived increases in children walking. RESULTS: From a database of 783 coordinators, 493 usable surveys were returned. Almost all respondents (98.2%) participated in a one-day WTS event. Other common activities included promotional activities (72.7%), safety trainings (49.6%), walkability audits (48.5%), and designated safe walking routes (46.5%). As part of their WTS efforts, 24.4% made policy changes and 38.4% made changes to the physical environment. Logistic regression analyses showed that policy changes, physical environment improvements, and number of activities were associated with the largest perceived increased in children walking to school. CONCLUSIONS: These findings help address the gap in knowledge about schools' participation in WTS programs, and suggest strategies to increase active transportation to school.

Determination of arsenic, cadmium, cobalt, chromium, lead, molybdenum, nickel, and selenium in fertilizers by microwave digestion and inductively coupled plasma-optical emission spectrometry detection: collaborative study.

There is increasing regulatory interest in the non-nutritive metals content of fertilizer materials, but at present there is no consensus analytical method for acid digestion and instrument detection of those elements in fertilizer matrixes. This lack of method standardization has resulted in unacceptable variability of results between fertilizer laboratories performing metals analysis. A method has been developed using microwave digestion with nitric acid at 200 degrees C, followed by inductively coupled plasma-optical emission spectrometry instrument detection, for the elements arsenic, cadmium, cobalt, chromium, molybdenum, nickel, lead, and selenium. The method has been collaboratively studied, and statistical results are here reported. Fourteen collaborators were sent 62 sample materials in a blind duplicate design. Materials represented a broad cross section of fertilizer types, including phosphate ore, manufactured phosphate products, N-P-K blends, organic fertilizers, and micro-nutrient materials. As much as possible within the limit of the number of samples, materials were selected from different regions of the United States and the world. Limit of detection (LOD) was determined using synthetic fertilizers consisting of reagent grade chemicals with near zero levels of the non-nutritive elements, analyzed blindly. Samples with high iron content caused the most variability between laboratories. Most samples reasonably above LOD gave HorRat values within the range 0.5 to 2.0, indicating acceptable method performance according to AOAC guidelines for analyses in the mg/kg range. The method is recommended for AOAC Official First Action status.

Errors in weight estimation in the emergency department: comparing performance by providers and patients.

To examine biases in weight estimation by Emergency Department (ED) providers and patients, a convenience sample of ED providers (faculty, residents, interns, nurses, medical students, paramedics) and patients was studied. Providers (n = 33), blinded to study hypothesis and patient data, estimated their own weight as well as the weight of 11-20 patients each. An independent sample of patients (n = 95) was used to assess biases in patients' estimation of their own weight. Data are represented as over, under, or within +/- 5 kg, the dose tolerance standard for thrombolytics. Logistic regression analysis revealed that patients are almost nine times more likely to accurately estimate their own weight than providers; yet 22% of patients were unable to estimate their own weight within 5 kg. Of all providers, paramedics were significantly worse estimators of patient weight than other providers. Providers were no better at guessing their own weight than were patients. Though there was no systematic estimate bias by weight, experience level (except paramedic), or gender for providers, those providers under 30 years of age were significantly better estimators of patient weight than older providers. Although patient gender did not create a bias in provider estimation accuracy, providers were more likely to underestimate women's weights than men's. In conclusion, patient self-estimates of weight are significantly better than estimates by providers. Inaccurate estimates by both groups could potentially contribute to medication dosing errors in the ED.

The perspective of paramedics about on-scene termination of resuscitation efforts for pediatric patients.

OBJECTIVES: The purpose of this study was to assess the attitude of paramedics to on-scene termination of cardiopulmonary resuscitation (T-CPR) efforts in children prior to developing a pediatric T-CPR policy. METHODS: A 26-item anonymous survey was conducted of all of the active paramedics in a large urban EMS system where T-CPR had been practiced routinely for adults. Questions addressed paramedic demographics, training level, experience with adult and pediatric advanced cardiac life support (ACLS), experience with T-CPR in adults, T-CPR case scenarios, and T-CPR in children. RESULTS: All 201 paramedics in the system (mean age=34.2 years; mean years as paramedic = 8.5 ) completed all relevant items of the survey (100% compliance). Two-thirds had provided ACLS for cardiac arrest to >50 adults (93% >10 adults) and more than one-third had performed ACLS on >20 children (72% >5 children). In addition, 90% had participated in T-CPR for adults. The majority of paramedics reported at least occasional (pre-defined) difficulty with adult T-CPR including family confrontation, 43%; personal discomfort, 13%; disagreement with physician decision to continue efforts, 11%; and fear of liability, 10%. Paramedic self ratings of comfort with terminating CPR on a scale from 1 to 10 (1: very comfortable; 10: uncomfortable) for adults and children were 1 and 9, respectively (P<0.001). In addition, the clear majority (72%) responded that children deserve more aggressive resuscitative efforts than adults. CONCLUSIONS: Paramedics feel relatively uncomfortable with the concept of terminating resuscitation efforts in children in the pre-hospital setting.

Tactical emergency medical support.

As increases in criminal activity collide with more aggressive law enforcement postures, there is more contact between police officers and violent felons. Civilian law enforcement special operations teams routinely engage suspects in these violent, dynamic, and complex interdiction activities. Along with these activities comes the substantial and foreseeable risk of death or grievous harm to law officers, bystanders, hostages, or perpetrators. Further, law enforcement agencies who attempt to apprehend dangerous, heavily armed criminals with a special operations team that lacks the expertise to treat the medical consequences that may arise from such a confrontation may be negligent of deliberate indifference. Meanwhile, evidence exists within the military, civilian law enforcement, and medical literature that on-scene TEMS serves to improve mission success and team safety and health, while decreasing morbidity and mortality in the event of an injury or illness suffered during operations. National professional organizations within law enforcement and emergency medicine have identified and support the fundamental need for mission safety and the development of a standard model to train and incorporate TEMS into law enforcement special operations. The overall objective of TEMS is to minimize the potential for injury and illness and to promote optimal medical care from the scene of operations to a definitive care facility. The design, staffing, and implementation of a TEMS program that maximally uses the community resources integrates previously disparate law enforcement, EMS, and emergency medical/trauma center functions to form a new continuum of care [55].