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This is the first sham-controlled trial to examine the effects of home-based leg heat therapy (HT) on walking performance in patients with peripheral artery disease (PAD). We demonstrate that unsupervised HT using water-circulating trousers is safe, well-tolerated, and elicits meaningful changes in walking ability in patients with symptomatic PAD. This home-based treatment option is practical, painless, and may be a feasible adjunctive therapy to counteract the decline in lower extremity physical function in patients with PAD.

Energy harvesting from rotating system has been an influential topic for researchers over the past several years. In this paper, we propose an energy harvester for rotating systems under modulated noise excitations by taking advantage of self-tuning stochastic resonance with particular application to power smart tires. Compared to existing tire energy harvesters, it has larger power output and wider bandwidth. The former is achieved by stochastic resonance while the latter is by passively tuning the stochastic resonance frequency to track the time varying rotating speeds of the tire via a centrifugal stiffening effect; thus, the harvester maintains optimal power generation over a wide range of vehicle speed. It is an electromagnetic energy harvester consisting of an inward oriented rotating beam subjected to centrifugal force induced buckling. The compressive centrifugal force induces bistability to the harvester. The equation of motion is derived to investigate the effect of self-tuning. The tuning performance is verified by analysis of Kramers rate and signal-to-noise ratio (SNR). Numerical simulation is conducted to simulate the harvested power in a passenger car tire at different driving speeds. Maximum power of 45 mW is achieved in the simulation. The half-power bandwidth of the harvester is around 52–111 km/h (32 mph–70 mph), which corresponds to a typical speed range for a car in general roads and highways. To validate the simulation results, experiment is conducted. A rotating platform is built to mimic the tire rotation. Experiment results show good agreement with the numerical simulation with around 10% of errors, which proves the feasibility of the proposed harvester. A frequency sweep test also shows that the harvester works well in frequency-varying environments which are close to real driving conditions.

Objectives Our aim was to describe the pharmacokinetics of cefazolin in paediatric patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) who received cefazolin for peri-operative surgical prophylaxis in addition to having cefazolin added to the CPB circuit priming solution. Secondary aims were to determine the pharmacodynamic exposure associated with the addition of cefazolin to the CPB priming solution and to assess whether a target cefazolin concentration range for the CPB priming solution could be identified. Methods A multicentre, prospective, open-label pharmacokinetic study was carried out in children from birth to 16 years of age undergoing cardiac surgery. Results Forty-one patients met the inclusion criteria and accounted for 492 samples for analysis. Cefazolin concentrations were best described by a one-compartment model with weight as a covariate on the volume of distribution (Vd) with allometric scaling. The mean ± standard deviation (SD) total body CL for the birth-6 month cohort was 0.009 ± 0.006 mL/min/kg with a mean ± SD Vd of 0.59 ± 0.26 L/kg, the mean ± SD total body CL for the 7 month-3 year cohort was 0.01 ± 0.005 mL/min/kg with a mean ± SD Vd of 0.79 ± 0.15 L/kg, and the mean ± SD total body CL for the 4-16 year cohort was 0.007 ± 0.004 mL/min/kg with a mean ± SD Vd of 3.4 ± 0.94 L/kg. The median cefazolin loss in the CPB circuit ranged from 78% to 95% and the median patient cefazolin concentration after CPB circuit detachment ranged from 92 to 197 mg/L. Conclusions These data demonstrate that mixing cefazolin in the CPB circuit priming solution was effective in maintaining cefazolin serum concentrations during surgery. If this practice is utilized, re-dosing of cefazolin during the CPB run and upon CPB circuit detachment is most probably not needed. Larger pharmacokinetic studies are warranted.

To every small category or topos one may associate its isotropy group, which is an algebraic invariant capturing information about the behaviour of automorphisms. We investigate this invariant in the particular situation of algebraic theories, thus obtaining a group-theoretic invariant of algebraic theories. This invariant encodes a notion of inner automorphism relative to the theory. Our main technical result is a syntactic characterization of the isotropy group of an algebraic theory, and we illustrate the usefulness of this characterization by applying it to various concrete examples of algebraic theories.

In this article, we characterize the (covariant) isotropy groups of free, finitely generated racks and quandles. As a consequence, we show that the usual inner automorphisms of such racks and quandles are precisely those automorphisms that are "coherently extendible". We then use this result to compute the global isotropy groups of the categories of racks and quandles, i.e. the automorphism groups of the identity functors of these categories., Added new reference and discussion of its results

We evaluate Beer–Lambert (BL) ray-tracing and Monte Carlo N-Particle (MCNP) photon tracking simulations for prediction and comparison of x-ray imaging system performance. These simulation tools can aid the methodical design of laboratory-scale x-ray particle image velocimetry (XPIV) experiments and tracer particles by predicting image quality. Particle image signal-to-noise ratio (SNR) is used as the metric of system performance. Simulated and experiment data of hollow, silver-coated, glass sphere tracer particles (AGSF-33) are compared. As predicted by the simulations, the AGSF-33 particles are visible with a SNR greater than unity in 100 ms exposure time images, demonstrating their potential as x-ray PIV or particle tracking velocimetry (XPTV) tracers. The BL approach predicts the image contrast, is computationally inexpensive, and enables the exploration of a vast parameter space for system design. MCNP simulations, on the other hand, predict experiment images slightly more accurately, but are more than an order of magnitude more computationally expensive than BL simulations. For most practical XPIV system design applications, the higher computational expense of MCNP is likely not justified by the modest accuracy improvement compared to BL.

The 2011 Food Safety Modernization Act (FSMA) exempts most small- and medium-scale growers in the U.S. from the new produce safety rule that creates a set of minimum safety standards for producing and processing fresh fruits and vegetables. While the exemption may limit the financial burden of growers in the short term, growers not willing or unable to meet food safety standards could lose out on market opportunities. In this article, we draw on a primary dataset of 301 survey responses from small- and medium-scale produce growers in New England (NE) and develop a conceptual framework for analyzing both objective and subjective factors associated with the on-farm adoption of food safety practices. We begin our analysis by exploring the extent to which growers report being financially able and willing to invest in food safety practices, and continue with an assessment of factors associated with the financial ability and willingness to adopt these practices. Regarding ability, we find that 24% of growers were able to adopt practices regardless of cost, while 64% were able to invest if not cost prohibitive. The odds of being able to invest increased 4% for every one-unit increase in the food safety knowledge test score and increased 20% for every one-unit increase in the number of practices implemented. In addition, the odds were 84% lower for those who reported financial barriers to adoption compared to those who did not. With respect to willingness, 46% of growers were willing to adopt practices regardless of cost, while 49% were willing if not cost prohibitive. The odds of being willing to invest increased 4% for every one-unit increase in food safety knowledge test score, were 4.9 times more likely for those who perceived no barriers to the implementation of practices, and were 2.7 times more likely for those who perceive that growers have a role to play in food safety. We conclude with a discussion of the practical implications for technical assistance providers, policy makers, and government agencies, as well as avenues for future research. These are centered around three points: (1) the high potential for adoption of food safety practices where cost remains a limiting factor, (2) a potential disconnect between the commonly used knowledge deficit approach to food safety training and what growers want and need to know, and (3) the importance of adopting a systemic approach to understand the realities of growers and the diversity of factors that shape the adoption of food safety practices.

To describe our experience with achieving therapeutic serum vancomycin concentrations in pediatric continuous renal replacement therapy by using continuous infusion vancomycin by mixing vancomycin into the continuous renal replacement therapy solution.Retrospective chart review.A 189-bed, freestanding children's tertiary care teaching hospital in Philadelphia, PA.Pediatric patients receiving continuous renal replacement therapy from April 1, 2009, through December 31, 2014.None.There were a total of 21 patients who received continuous renal replacement therapy during the study period. Of these, 11 (52.3%) received vancomycin in the continuous renal replacement therapy solution. The median (range) concentration of vancomycin added to the continuous renal replacement therapy solution was 25 mg/L (18-35 mg/L). The mean vancomycin plateau level was 22.8 ± 3.3 mg/L. All patients achieved a serum vancomycin plateau level that was greater than 15 mg/L. There were no adverse events related to the addition of vancomycin to the continuous renal replacement therapy solution.The addition of vancomycin to the continuous renal replacement therapy solution(s) is an effective modality that is used for delivering vancomycin continuous infusion and for ensuring therapeutic vancomycin serum plateau levels in the setting of pediatric continuous renal replacement therapy. Further studies are required to evaluate whether this delivery method can lead to improved patient outcomes.

This article has the following contributions. First, this article develops a new criterion for identifying whether or not a particular time series variable is a common factor in the conventional approximate factor model. Second, by modeling observed factors as a set of potential factors to be identified, this article reveals how to easily pin down the factor without performing a large number of estimations. This allows the researcher to check whether or not each individual in the panel is the underlying common factor and, from there, identify which individuals best represent the factor space by using a new clustering mechanism. Asymptotically, the developed procedure correctly identifies the factor when N and T jointly approach infinity. The procedure is shown to be quite effective in the finite sample by means of Monte Carlo simulation. The procedure is then applied to an empirical example, demonstrating that the newly developed method identifies the unknown common factors accurately.

BackgroundWe reviewed all patients who were supported with extracorporeal membrane oxygenation and/or ventricular assist device at our institution in order to describe diagnostic characteristics and assess mortality.MethodsA retrospective cohort study was performed including all patients supported with extracorporeal membrane oxygenation and/or ventricular assist device from our first case (8 October, 1998) through 25 July, 2016. The primary outcome of interest was mortality, which was modelled by the Kaplan–Meier method.ResultsA total of 223 patients underwent 241 extracorporeal membrane oxygenation runs. Median support time was 4.0 days, ranging from 0.04 to 55.8 days, with a mean of 6.4±7.0 days. Mean (±SD) age at initiation was 727.4 days (±146.9 days). Indications for extracorporeal membrane oxygenation were stratified by primary indication: cardiac extracorporeal membrane oxygenation (n=175; 72.6%) or respiratory extracorporeal membrane oxygenation (n=66; 27.4%). The most frequent diagnosis for cardiac extracorporeal membrane oxygenation patients was hypoplastic left heart syndrome or hypoplastic left heart syndrome-related malformation (n=55 patients with HLHS who underwent 64 extracorporeal membrane oxygenation runs). For respiratory extracorporeal membrane oxygenation, the most frequent diagnosis was congenital diaphragmatic hernia (n=22). A total of 24 patients underwent 26 ventricular assist device runs. Median support time was 7 days, ranging from 0 to 75 days, with a mean of 15.3±18.8 days. Mean age at initiation of ventricular assist device was 2530.8±660.2 days (6.93±1.81 years). Cardiomyopathy/myocarditis was the most frequent indication for ventricular assist device placement (n=14; 53.8%). Survival to discharge was 42.2% for extracorporeal membrane oxygenation patients and 54.2% for ventricular assist device patients. Kaplan–Meier 1-year survival was as follows: all patients, 41.0%; extracorporeal membrane oxygenation patients, 41.0%; and ventricular assist device patients, 43.2%. Kaplan–Meier 5-year survival was as follows: all patients, 39.7%; extracorporeal membrane oxygenation patients, 39.7%; and ventricular assist device patients, 43.2%.ConclusionsThis single-institutional 18-year review documents the differential probability of survival for various sub-groups of patients who require support with extracorporeal membrane oxygenation or ventricular assist device. The indication for mechanical circulatory support, underlying diagnosis, age, and setting in which cannulation occurs may affect survival after extracorporeal membrane oxygenation and ventricular assist device. The Kaplan–Meier analyses in this study demonstrate that patients who survive to hospital discharge have an excellent chance of longer-term survival.

Livestock industries are vulnerable to disease threats, which can cost billions of dollars and have substantial negative social ramifications. Losses are mitigated through increased use of disease-related biosecurity practices, making increased biosecurity an industry goal. Currently, there is no industry-wide standard for sharing information about disease incidence or on-site biosecurity strategies, resulting in uncertainty regarding disease prevalence and biosecurity strategies employed by industry stakeholders. Using an experimental simulation game, we examined human participant's willingness to invest in biosecurity when confronted with disease outbreak scenarios. We varied the scenarios by changing the information provided about 1) disease incidence and 2) biosecurity strategy or response by production facilities to the threat of disease. Here we show that willingness to invest in biosecurity increases with increased information about disease incidence, but decreases with increased information about biosecurity practices used by nearby facilities. Thus, the type or context of the uncertainty confronting the decision maker may be a major factor influencing behavior. Our findings suggest that policies and practices that encourage greater sharing of disease incidence information should have the greatest benefit for protecting herd health., Comment: 26 pages, 6 figures

Deafferentation of the spinal cord has been shown to produce extensive reorganization of the corresponding deafferented cortex. However, the role of the adjacent intact motor cortex and the integration between the primary motor (M1) and primary sensory cortex (S1) in this reorganization is not fully understood. In this study, we show that a contusion of the spinal cord increases the evoked responses of the forelimb, trunk, hindlimb, and tail motor cortices to forepaw stimuli in Layer II/III of anesthetized Sprague Dawley rats. Further, we show the identification of new evoked potentials to forelimb stimuli in motor regions below the level of the lesion. We also show a feasible stereotaxic solution for the simultaneous recording of evoked potentials from Layers I - V of M1 and S1. The increased responses in the forelimb motor cortex, coupled with the increased identification of evoked responses in the deafferented hindlimb and tail motor cortices, suggest that spatial reorganization of neuronal fibers within the motor cortex occurs through mechanisms involving the sprouting of either cortico-cortical connections from neighboring intact motor regions, or through sprouting of thalamocortical projections.

Neither guidelines nor best practices for the treatment of external ventricular drain (EVD) and ventriculoperitoneal shunt infections exist. An antimicrobial regimen with a broad spectrum of activity and adequate cerebrospinal fluid (CSF) penetration is vital in the management of both EVD and ventriculoperitoneal infections. In this case report, we describe the pharmacokinetics of continuous-infusion meropenem for a 2-year-old girl with Serratia marcescens ventriculitis. A right frontal EVD was placed for the management of a posterior fossa mass with hydrocephalus and intraventricular hemorrhage. On hospital day 6, CSF specimens were cultured, which identified a pan-sensitive Serratia marcescens with an initial cefotaxime minimum inhibitory concentration of 1 μg/ml or less. The patient was treated with cefotaxime monotherapy from hospital days 6 to 17, during which her CSF cultures and Gram's stain remained positive. On hospital day 26, Serratia marcescens was noted to be resistant to cefotaxime (minimum inhibitory concentration > 16 μg/ml), and the antimicrobial regimen was ultimately changed to meropenem and amikacin. Meropenem was dosed at 40 mg/kg/dose intravenously every 6 hours, infused over 30 minutes, during which, simultaneous serum and CSF meropenem levels were measured. Meropenem serum and CSF levels were measured at 2 and 4 hours from the end of the infusion with the intent to perform a pharmacokinetic/pharmacodynamic analysis. The resulting serum meropenem levels were 12 μg/ml at 2 hours and “undetectable” at 4 hours, with CSF levels of 1 and 0.5 μg/ml at 2 and 4 hours, respectively. On hospital day 27, the meropenem regimen was changed to a continuous infusion of 200 mg/kg/day, with repeat serum and CSF meropenem levels measured on hospital day 33. The serum and CSF levels were noted to be 13 and 0.5 μg/ml, respectively. The serum level of 13 μg/ml corresponds to an estimated meropenem clearance from the serum of 10.2 ml/kg/minute. Repeat meropenem levels from the serum and CSF on hospital day 37 were 15 and 0.5 μg/ml, respectively. After instituting the continuous-infusion meropenem regimen, only three positive CSF Gram's stains were noted, with the CSF cultures remaining negative. The continuous-infusion dosing regimen allowed for 100% probability of target attainment in the serum and CSF and a successful clinical outcome.

Meropenem, a broad-spectrum carbapenem, is commonly used for empirical and definitive therapy in the pediatric intensive care unit (ICU). Pharmacokinetic data to guide dosing in children, however, are limited to healthy volunteers or patients who are not in the ICU. Adult data demonstrate that pharmacokinetic parameters such as the volume of distribution and clearance can be significantly altered in individuals receiving extracorporeal membrane oxygenation (ECMO). Alterations in the volume of distribution and clearance of antimicrobials in patients with sepsis and septic shock have also been documented, and these patients have demonstrated lower than expected antimicrobial serum concentrations based on standard dosing regimens. Therefore, an understanding of the pharmacokinetic changes in critically ill children receiving ECMO is crucial to determining the most appropriate dose and dosing interval selection for any antimicrobial therapy. In this case report, we describe the pharmacokinetics of a continuous infusion of meropenem in a pediatric cardiac ICU patient who was receiving concurrent extracorporeal life support. The patient was an 8-month-old male infant who underwent a Glenn procedure and pulmonary artery reconstruction. Postoperatively, he required ECMO with a total run of 21 days. On day 11 of ECMO, a bronchoalveolar lavage was performed, and blood cultures from days 11 and 12 of ECMO grew Pseudomonas aeruginosa, with a meropenem minimum inhibitory concentration (MIC) of 0.5 μg/ml. On ECMO day 13, meropenem was initiated with a loading dose of 40 mg/kg and infused over 30 minutes, followed by a continuous infusion of 200 mg/kg/day. A meropenem serum concentration measured 8 hours after the start of the infusion was 46 μg/ml. Repeat levels were measured on days 3 and 9 of meropenem therapy and were 39 and 42 μg/ml, respectively. Repeat blood and respiratory cultures remained negative. This meropenem regimen (40-mg/kg bolus followed by a continuous infusion of 200 mg/kg/day) was successful in providing a target attainment of 100% for serum and lung concentrations above the MIC for at least 40% of the dosing interval and was associated with a successful clinical outcome.

We report an effect in vertically-aligned carbon nanotube growth in which small catalyst features in proximity to large features show an enhanced growth rate. We apply this so-called “synergetic growth” effect in micrometer-scale patterns to produce vertical-like growth horizontally. This approach enables carbon nanotube integration into device applications requiring a fair degree of carbon nanotube alignment. The synergetic growth effect corroborates growth mechanisms describing carbon nanotube growth as a more complex process than elemental carbon supersaturating metal catalyst.

Energy-harvesting series electromagnetic-tuned mass dampers (EMTMDs) have been recently proposed for dual-functional energy harvesting and robust vibration control by integrating the tuned mass damper (TMD) and electromagnetic shunted resonant damping. In this paper, we derive ready-to-use analytical tuning laws for the energy-harvesting series EMTMD system when the primary structure is subjected to force or ground excitations. Both vibration mitigation and energy-harvesting performances are optimized using H2 criteria to minimize root-mean-square (RMS) values of the deformation of the primary structure or maximize the average harvestable power. These analytical tuning laws can easily guide the design of series EMTMDs under various external excitations. Later, extensive numerical analysis is presented to show the effectiveness of the series EMTMDs. The numerical analysis shows that the series EMTMD more effectively mitigates the vibration of the primary structure nearly across the whole frequency spectrum, compared to that of classic TMDs. Simultaneously, the series EMTMD can better harvest energy due to its broader bandwidth effect. Beyond simulations, this paper also experimentally verifies the effectiveness of the series EMTMDs in both vibration mitigation and energy harvesting.

Background Vital statistics on the number of, alcohol-induced death (AICD) drug-induced death (DICD), and suicides at the local-level are only available after a substantial lag of up to two years after the events occur. We (1) investigate how well Google Trends search data explain variation in state-level rates in the US, and (2) use this method to forecast these rates of death for 2015 as official data are not yet available. Methods We tested the degree to which Google Trends data on 27 terms can be fit to CDC data using L1-regularization on AICD, DICD, and suicide. Using Google Trends data, we forecast 2015 AICD, DICD, and suicide rates. Results L1-regularization fit the pre-2015 data much better than the alternative model using state-level unemployment and income variables. Google Trends data account for substantial variation in growth of state-level rates of death: 30.9% for AICD, 23.9% for DICD, and 21.8% for suicide rates. Every state except Hawaii is forecasted to increase in all three of these rates in 2015. Limitations The model predicts state, not local or individual behavior, and is dependent on continued availability of Google Trends data. Conclusions The method predicts state-level AICD, DICD, and suicide rates better than the alternative model. The study findings suggest that this methodology can be developed into a public health surveillance system for behavioral health-related causes of death. State-level predictions could be used to inform state interventions aimed at reducing AICD, DICD, and suicide.

Energy-harvesting series electromagnetic tuned mass dampers (EMTMDs) have been recently proposed for dual-functional energy harvesting and robust vibration control by integrating the tuned mass damper (TMD) and electromagnetic shunted resonant damping. In this paper, we derive ready-to-use analytical tuning laws for the energy-harvesting series EMTMD system when the primary structure is subjected to force or ground excitations, like wind loads or earthquakes. Both vibration mitigation and energy harvesting performances are optimized using H2 criteria to minimize root-mean-square values of the deformation of the primary structure, or maximize the average harvestable power. These analytical tuning laws can easily guide the design of series EMTMDs under various ambient loadings. Later, extensive numerical analysis is presented to show the effectiveness of the series EMTMDs. The numerical analysis shows that the series EMTMD is superior to mitigate the vibration of the primary structure nearly across the whole frequency spectrum, as compared to that of classic TMDs. Simultaneously, the series EMTMD can better harvest the energy due to broader bandwidth effect. Beyond simulations, this paper also experimentally verifies the effectiveness of the energy-harvesting series electromagnetic TMDs in both vibration mitigation and energy harvesting.

Pharmacokinetic parameters can be significantly altered for both extracorporeal life support (ECLS) and continuous renal replacement therapy (CRRT). This case report describes the pharmacokinetics of continuous-infusion meropenem in a patient on ECLS with concurrent CRRT. A 2.8-kg, 10-day-old, full-term neonate born via spontaneous vaginal delivery presented with hypothermia, lethargy, and a ~500-g weight loss from birth. She progressed to respiratory failure on hospital day 2 (HD 2) and developed sepsis, disseminated intravascular coagulation, and liver failure as a result of disseminated adenoviral infection. By HD 6, acute kidney injury was evident, with progressive fluid overload >1500 mL (+) for the admission. On HD 6 venoarterial ECLS was instituted for lung protection and fluid removal. On HD 7 she was initiated on CRRT. On HD 12, a blood culture returned positive and subsequently grew Pseudomonas aeruginosa with a minimum inhibitory concentration (MIC) for meropenem of 0.25 mg/L. She was started on vancomycin, meropenem, and amikacin. A meropenem bolus of 40 mg/kg was given, followed by a continuous infusion of 10 mg/kg/hr (240 mg/kg/day). On HD 15 (ECLS day 9) a meropenem serum concentration of 21 mcg/mL was obtained, corresponding to a clearance of 7.9 mL/kg/min. Repeat cultures from HDs 13 to 15 (ECLS days 7–9) were sterile. This meropenem regimen was successful in providing a target attainment of 100% for serum concentrations above the MIC for ≥40% of the dosing interval and was associated with a sterilization of blood in this complex patient on concurrent ECLS and CRRT circuits.

The carbon source and growth conditions for single-walled carbon nanotube (SWCNT) growth in hot-wall chemical vapor deposition affect the chirality of the SWCNT ensemble produced. Raman spectroscopy elucidates the trends of the SWCNT semiconducting percentage grown under different conditions. Field-effect transistors using few SWCNTs per transistor were fabricated to allow for a semiconducting SWCNT enumeration and to confirm these trends. The semiconducting SWCNT percent in isopropanol-based devices peaked at 800 °C with 85% semiconducting. 2-Butanol-based and methane-based devices were 70% and 32% semiconducting, respectively.

Community research by anthropologists and sociologists details the effects that centralization of decision making has on local communities. As governance and regulation move toward global scales, conservation policy has devolved to the local levels, creating tensions in resource management and protection. Centralization without local participation can place communities at risk by eroding the environmental knowledge and decision making capacity of local people. Environmental problems such as water quality impairments require perception, interpretation, and ability to act locally. Through a presentation of findings from farm communities in the Sugar Creek Watershed (Northeast Ohio, USA), this paper examines tradition, social scale, and land use among Anabaptist and other farm households, and refocuses on-farm conversation away from conventional individual metric-based studies and toward a systems approach. This new approach frames conservation behavior in a socio-cultural system that is influenced by tradition in on-farm decision making. Data from four subwatersheds are used to probe the effects of these variables on conservation adoption, explore the optimal farm size concept, and discus the roles of tradition and local and non-local knowledge in sustainability.

This research intends to refocus the on-farm fresh produce food safety paradigm away from an emphasis on knowledge deficit models and ready-made or tightly-coupled, reductionist solutions toward a loosely-coupled systems approach. The dynamic environment of produce farming and multi-dimensional objectives of produce growers create manifold pathways to address farm-specific food safety concerns. We propose a systems approach to facilitate increased decision making of growers using farm-specific criteria to improve their efforts. Currently, social and psychological dimensions of fresh produce food safety are overlooked in program development with preference given to bio-physical knowledge and technological solutions. In this paper, we describe a comprehensive model that was developed through a formal expert elicitation and literature review for the purpose of enhancing education and policy development and improving the microbiological safety of fresh and fresh cut produce. This model illuminates the intrinsic interrelationships among farm scale, marketing practices, and the need for appropriate food safety interventions. We further discuss how this loosely-coupled systems perspective can both aid our understanding of grower decision making and provide a basis for developing equitable solutions to on-farm food safety issues as part of a social-psychological approach to addressing these issues.

Experts identified water quality, manure, good handling practices (including personal hygiene and equipment sanitation), and traceability as critical farm problem areas that, if addressed, are likely to decrease risk associated with microbial contamination of fresh produce from all scales of agriculture. However, the diverse nature of production strategies used by produce farmers presents multiple options for addressing foodborne illness issues while simultaneously creating potential complications. We use a mental models methodology to enhance our understanding of the underlying factors and assumptions of small, medium, and large produce growers that influence their decision-making processes for contamination prevention and control. This empirical evidence demonstrates how challenges and opportunities to food safety are related to the scale of production and marketing strategies. We believe that refining the development of standards and existing extension and outreach food safety programs are important to both consumer protection and supporting agricultural communities. Additionally, this approach will help develop and refine food safety programs that will result in empirically grounded recommendations based on identified grower information needs.