A Test of the Validity of Imputed Legal Immigration Status.

We evaluate the performance of a widely used technique for imputing the legal immigration status of U.S. immigrants in survey data-the logical imputation method. We validate this technique by implementing it in a nationally representative survey of U.S. farmworkers that includes a well-regarded measure of legal status. When using this measure as a benchmark, the imputation algorithm correctly identifies the legal status of 78% of farmworkers. Of all the variables included in the algorithm, we find that Medicaid participation poses the greatest challenge for accuracy. Using the American Community Survey, we show that increased Medicaid enrollments stemming from the implementation of the Affordable Care Act in 2014 led to sizable changes in the share of immigrants imputed as legal over time and across space. We explore the implications of these changes for two previous studies and conclude that including Medicaid criteria in the imputation algorithm can significantly impact research findings. We also provide tools to gauge the sensitivity of results.

Clinical and cerebrospinal fluid findings contribute to the early differentiation between infectious and noninfectious encephalitis.

Early recognition and prompt specific treatment are crucial factors influencing the outcome of patients with acute encephalitis. The aim of this study was to determine the main causes of acute encephalitis in our population and to find predictors that may lead to specific diagnosis. Adult patients admitted to our hospital with suspected diagnosis of encephalitis in the period 2006-2013 were included. One hundred and five medical records were analyzed. Eighty-two patients with infectious encephalitis were identified (78% of total cases), 53 (65%) men and 29 (35%) women, mean age 47.8 years. The most common microorganisms identified were: HSV-1 (11%), VZV (10%), HSV-2 (5%) and EBV (5%). Twenty-three patients (22% of the series) had non-infectious encephalitis. Headache (p < 0.0001) and fever (p = 0.008) were more frequent in encephalitis of infectious origin. Protein levels and white blood cell counts in the cerebrospinal fluid were significantly higher in patients affected by infectious encephalitis than in those affected by noninfectious encephalitis (OR 95% CI 12.3 [2.9-51.7] and OR 95% CI 7.4 [2-27], respectively). Identifying specific causal agents of acute encephalitis remains a major challenge. Cerebrospinal fluid markers, as well as specific clinical findings, may however contribute to initial differentiation between infectious and noninfectious causes.

Laguerre-Gauss beams versus Bessel beams showdown: peer comparison.

We present for the first time a comparison under similar circumstances between Laguerre-Gauss beams (LGBs) and Bessel beams (BB), and show that the former can be a better option for many applications in which BBs are currently used. By solving the Laguerre-Gauss differential equation in the asymptotic limit of a large radial index, we find the parameters to perform a peer comparison, showing that LGBs can propagate quasi-nondiffracting beams within the same region of space where the corresponding BBs do. We also demonstrate that LGBs, which have the property of self-healing, are more robust in the sense that they can propagate further than BBs under similar initial conditions.

Intra-abdominal infections due to Comamonas kerstersii.

Herein, we report four cases of Comamonas kerstersii intra-abdominal infections representing the first report of human infections caused by this Comamonas species. In addition, our work demonstrates the association of C. kerstersii with peritonitis secondary to appendix rupture.

Sensitivity optimization of the one beam Z-scan technique and a Z-scan technique immune to nonlinear absorption.

It is presented a criteria for selecting the optimum aperture radius for the one beam Z-scan technique (OBZT), based on the analysis of the transmittance of the aperture. It is also presented a modification to the OBZT by directly measuring the beam radius in the far field with a rotating disk, which allows to determine simultaneously the non-linear absorptive coefficient and non-linear refractive index, much less sensitive to wave front distortions caused by inhomogeneities of the sample with a negligible loss of signal to noise ratio. It is demonstrated its equivalence to the OBZT.

[Candida: epidemiology and risk factors for non-albicans species]. / Candida: epidemiología y factores de riesgo para especies no albicans.

INTRODUCTION: Nosocomial fungal infections have increased significantly in the last decade. Candida detection in clinical specimens can mean either colonization or an infection which can be local (muguet) or invasive. Knowledge of the species helps in choosing the best treatment. The aims of this study were to determine the frequency and distribution of Candida species detected in clinical samples, to analyze the clinical characteristics of the involved population and to determine the risk factors for Candida non-albicans species. METHODS: Retrospective, observational. PERIOD: 2006-2010. INCLUSION CRITERIA: all isolates of Candida in clinical specimens from patients hospitalized at least 48 hours in a neurological center. We analyzed epidemiological characteristics, co morbidities, risk factors, factors associated with Candida non-albicans detection, antifungal treatment, development of adverse events and mortality. RESULTS: Candida spp. was isolated from 321 clinical specimens: 139 (43.3%) were C. albicans and 182 (56.7%) Candida non-albicans. The distribution of the sample was: urine 122 (Candida non-albicans 67.2%), airway 81, oropharynx 45 (C. albicans) and candidemia 40 (Candida non-albicans 75%). The most frequent co-morbidity was solid tumor (35.5%). The main risk factors were antibiotic therapy (85.5%), steroid therapy (61.7%) and in ICU at diagnosis (61.6%). The analysis of risk factors and the isolation of Candida non-albicans shows that chemotherapy, previous surgery, treatment with aminopenicillins, carbapenems and glycopeptides were statistically significant (P<.05). There is a trend in neutropenic patients (P=.055) and in ICU at diagnosis (P=.076). Overall survival was 71%. CONCLUSIONS: Candida species distribution varies with the type of sample analyzed. Non-albicans species make up the majority of the isolates. The identification of the species involved per sample helps to optimize treatment. The high frequency of isolation of Candida in patients on steroids and antibiotics and admitted to ICU, is worth pointing out. Patients with previous surgery, treated with the aforementioned antibiotics or chemotherapy, could receive non-azole antifungals in the initial empirical treatment strategy.

[Ocular syphilis: alert for clinicians and ophthalmologists]. / Sífilis ocular: alerta para clínicos y oftalmólogos.

Syphilis is an infectious disease caused by the spirochete Treponema pallidum. It can cause ocular compromise at any stage, in immunocompetent or immunocompromised patients. Even though the ocular form is not frequent, due to the increase in the incidence of syphilis in recent years, it is mandatory to take it into consideration as a differential diagnosis in visual disorders. The most common clinical presentation is uveitis. Diagnosis is based on the presence of clinical signs and symptoms consistent with ophthalmologic involvement in a patient with syphilis. The CSF study should be performed on a clinical basis, to rule out concomitant neurological involvement. We present 5 cases of ocular syphilis, its clinical manifestations, treatment and evolution.

La sífilis es una enfermedad infecciosa causada por la espiroqueta Treponema pallidum. Puede producir compromiso ocular en cualquier estadio, en pacientes inmunocompetentes o inmunocomprometidos. Si bien la frecuencia de presentación de la forma ocular no es alta, debido al aumento de la incidencia de sífilis en los últimos años, es necesario tenerla en cuenta como diagnóstico diferencial en los trastornos visuales. La presentación clínica más frecuente es la uveítis. Se objetiva ante la presencia de signos y síntomas clínicos consistentes con afectación oftalmológica en un paciente con sífilis. El estudio del LCR debe realizarse ante la sospecha clínica, para descartar compromiso neurológico concomitante. Comunicamos 5 casos de sífilis ocular, sus manifestaciones clínicas, tratamiento y evolución.

[Placenta: motivations, uses, and meanings in south central Chile]. / Placenta: móviles, usos y significaciones en el centro-sur de Chile.

Motivations, uses, and meanings given to the placenta by women and men in south central Chile are analyzed, following the implementation of Technical Standard 189 by the Ministry of Health, which allowed people to request their placentas after giving birth on hospital grounds. From an ethnographic approach to the sociocultural uses of placentas, in-depth interviews were carried out with women and their partners between July and November 2019; individual narratives were recorded, as well as conversations between Mapuche women and men who had requested their placenta in three Chilean regions (Araucania, Metropolitan, and Arica and Parinacota). This article focuses on four cases that illustrate the diversity of practices and knowledge surrounding the placenta - inscribed in sociocultural, territorial, political, spiritual, and religious frameworks - according to actors' sociocultural origins. To conclude, the cases are compared in order to highlight both similarities and differences, and some challenges derived from the findings are considered.

Se analizan los móviles, usos y significaciones atribuidos a las placentas por mujeres y hombres en el centro-sur de Chile, a partir de la implementación de la Norma Técnica 189 del Ministerio de Salud, que permite a las personas solicitar y disponer de sus placentas con posterioridad al parto en recintos hospitalarios. A través de una mirada etnográfica acerca del tratamiento sociocultural de las placentas, entre julio y noviembre de 2019 se realizaron entrevistas en profundidad con mujeres y sus parejas; se recogieron relatos individuales, así como conversaciones con mujeres y hombres mapuches, habitantes del territorio chileno de la región de La Araucanía, la región Metropolitana y la región de Arica y Parinacota, que habían solicitado la placenta. El artículo se enfoca en cuatro casos que dan cuenta de la presencia de diversas prácticas y conocimientos en torno a la placenta, estableciendo su inscripción en marcos socioculturales, territoriales y políticos, espirituales y religiosos, según la pertenencia sociocultural de los actores. Como conclusión, se contrastan los casos relevando tanto diferencias como similitudes y se proyectan algunos desafíos derivados de los hallazgos.

[Multicenter study of COVID-19 incidence and determinants in Argentinian physicians]. / Estudio multicéntrico de incidencia y determinantes de COVID-19 en médicos de Argentina.

BACKGROUND: Information about COVID infection in physicians is limited. This knowledge would allow the implementation of actions to reduce its impact. The objective was determining the incidence of SARSCoV-2 infection in physicians from health institutions in Argentina, its characteristics, and associated factors. METHODS: We conducted a multicenter prospective / retrospective cohort study with nested case-control study. Physicians active at the beginning of the pandemic were included, those on leave due to risk factors were excluded. The incidence of confirmed cases was estimated. We conducted bivariate analyses with various factors and used those significant in a logistic regression. RESULTS: Three hundred and forty three physicians with COVID-infection from 8 centers were included. The incidence of disease was 12.1% and that of global absenteeism related to COVID, 34.1%. Almost 70% of close contacts were work-related. In the multivariate analysis living in Autonomous City of Buenos Aires (CABA) (OR 0.19, p = 0.01), working in high-risk areas (OR 0.22, p = 0.01) and individual transportation (OR 0, 34, p = 0.03) reduced the risk of COVID. The odds of infection increased 5.6 times (p = 0.02) for each close contact isolation. DISCUSSION: The number of close contact isolation increased considerably the risk of infection. Living in Buenos Aires City, individual transportation and working in high-risk areas reduced it. Given the high frequency of close contact in the workplace, we strongly recommend the reinforcement of prevention measures in rest areas and non-COVID-wards.

Introducción: La información sobre COVID en médicos es limitada. Su conocimiento permitiría implementar acciones para reducir su impacto. El objetivo general fue determinar la incidencia de infección por SARS-CoV-2 en médicos de instituciones de salud de Argentina, sus características y factores asociados. Materiales y Métodos: Se realizó un estudio multicéntrico de cohorte prospectiva/retrospectiva con estudio de casos-controles anidado. Se incluyeron médicos activos al inicio de la pandemia no exceptuados por riesgo. Se estimó incidencia de casos confirmados. Se compararon factores asociados en casos y controles y se creó un modelo de regresión logística con las variables significativas del análisis bivariado. Resultados: Se incluyeron 343 médicos con COVID de 8 centros. La incidencia de la enfermedad fue de 12.1% y la de ausentismo global relacionado a COVID, de 34.1%. El 70% de los contactos estrechos fueron laborales. En el análisis multivariado de casos y controles, la residencia en la Ciudad Autónoma de Buenos Aires (OR 0.19, p = 0.01), el trabajo en áreas de alto riesgo (OR 0.22, p = 0.01) y vehículo individual (OR 0.34, p = 0.03) redujeron el riesgo de COVID. El odds de enfermar aumentó 4.6 veces (p = 0.02) por cada aislamiento por contacto estrecho. Discusión: El riesgo de enfermar aumentó considerablemente con cada aislamiento por contacto estrecho. La residencia en Ciudad Autónoma, el traslado en vehículo individual y el trabajo en áreas de alto riesgo lo redujeron. Dada la alta frecuencia de contactos estrechos en el ámbito laboral recomendamos reforzar las medidas de prevención en áreas de descanso y no COVID.

Potential Impacts of a Pandemic on the US Farm Labor Market.

An outbreak of COVID-19 among farmworkers could have significant impacts on the workers, agricultural producers, and the consumers. Farmers are implementing new labor management practices to slow the spread of the virus among workers. Since immigration is temporarily restricted, farmers may have difficulty securing a sufficient workforce. We test whether changes in the unemployment rate affected H-2A guest worker demand before the pandemic and find a statistically significant negative impact. Nevertheless, we expect that H-2A recruitment will be vital to sustaining agricultural production. We conclude by discussing potential long-term impacts of the pandemic on farm labor supply and demand.

[Post-neurosurgical infections. Update and intersociety recommendations]. / Infecciones postneuroquirúrgicas. Puesta al día y recomendaciones intersociedades.

Infections associated with neurosurgical procedures are serious complications that contribute to the morbidity and mortality of neurocritical patients, as well as to the prolongation of the stay in the ICU and the hospital. The diagnosis is complex since there is no gold standard, so it is based on clinical suspicion, CSF physical-chemical examination, and microbial isolation. Treatment should be initiated early, guided by local epidemiology. The duration will depend on the causative microorganism, its sensitivity and the availability of antibiotic treatments that are effective at the site of infection. The implementation of preventive measures with proven efficacy minimizes the risk of infection. This SADI-SATI intersociety update reviews relevant data recently published on this area at the national at international level regarding epidemiology, diagnostic methodologies, therapeutic approaches, and prevention guidelines.

Las infecciones asociadas a procedimientos neuroquirúrgicos son complicaciones graves que contribuyen a la morbimortalidad de los pacientes neurocríticos, así como también a la prolongación de la estancia en la UTI y/o en el hospital. El diagnóstico es complejo ya que no se dispone de gold standard y se apoya en la sospecha clínica, las alteraciones físico-químicas del líquido cefalorraquídeo y el aislamiento microbiano. El tratamiento debe ser precoz y guiado por la epidemiología local. La duración dependerá del microorganismo causal, su sensibilidad y la disponibilidad de tratamientos antibióticos efectivos en el sitio de la infección. La implementación de medidas de prevención con evidencia demostrada minimiza el riesgo de infección. Esta puesta al día intersociedades SADI-SATI presenta datos epidemiológicos (internacionales y locales), métodos diagnósticos, tratamiento, y pautas de prevención, considerando las publicaciones más relevantes de los últimos años sobre el tema.

Sífilis ocular: alerta para clínicos y oftalmólogos / Ocular syphilis: alert for clinicians and ophthalmologists

Resumen La sífilis es una enfermedad infecciosa causada por la espiroqueta Treponema pallidum. Puede producir com promiso ocular en cualquier estadio, en pacientes in munocompetentes o inmunocomprometidos. Si bien la frecuencia de presentación de la forma ocular no es alta, debido al aumento de la incidencia de sífilis en los últimos años, es necesario tenerla en cuenta como diagnóstico diferencial en los trastornos visuales. La presentación clínica más frecuente es la uveítis. Se objetiva ante la presencia de signos y síntomas clínicos consistentes con afectación oftalmológica en un pacien te con sífilis. El estudio del LCR debe realizarse ante la sospecha clínica, para descartar compromiso neurológi co concomitante. Comunicamos 5 casos de sífilis ocular, sus manifestaciones clínicas, tratamiento y evolución.

Abstract Syphilis is an infectious disease caused by the spi rochete Treponema pallidum. It can cause ocular compro mise at any stage, in immunocompetent or immunocom promised patients. Even though the ocular form is not frequent, due to the increase in the incidence of syphilis in recent years, it is mandatory to take it into consider ation as a differential diagnosis in visual disorders. The most common clinical presentation is uveitis. Diagnosis is based on the presence of clinical signs and symptoms consistent with ophthalmologic involvement in a patient with syphilis. The CSF study should be performed on a clinical basis, to rule out concomitant neurological involvement. We present 5 cases of ocular syphilis, its clinical manifestations, treatment and evolution.

Clinical Correlations of Positive Herpes Simplex PCR in Cerebrospinal Fluid.

OBJECTIVES: Herpes simplex viruses (HSV) can produce encephalitis (HSE), which requires early detection, typically using polymerase chain reaction (PCR) in cerebrospinal fluid (CSF). However, other neurological conditions not directly caused by HSV may also present with a positive HSV PCR in the CSF (NCNHPCR+). We aimed to analyze the clinical features of both groups of patients (HSE vs. NCNHPCR+) and to consider the potential relevance of this finding in the latter. METHODS: A retrospective analysis of clinical presentation, workup (CSF, EEG, and MRI) and outcome of patients with an HSV+ result in CSF was conducted from Jan-2007 to Sep-2015 in our institution. Patients under 18 years and those with nonencephalitic HSV associated disorders were excluded. Group comparison between HSE and NCNHPCR+ patients was conducted using parametric and nonparametric tests accordingly. RESULTS: Sixteen HSE and 23 NCNHPCR+ patients were included. Patients with HSE presented a higher incidence of headache (87.5% vs. 43.5%; P=0.008), meningeal symptoms (50% vs. 17.4%; P=0.04), pleocytosis (75% vs. 18%; P=0.001), EEG abnormalities (46.67% vs. 22%; P=0.02) and typical MRI findings (50% vs. 0%; P<0.001), whereas 35% of patients with NCNHPCR+ had an underlying immunologic disorder (35% vs. 0%; P=0.012). CONCLUSIONS: The pathogenic role of HSV in NCNHPCR+ is uncertain. This finding must be interpreted in the appropriate clinical, EEG, and neuroimaging context. Immunocompromise and neuroinflammation states could be related to a higher presence of HSV in CSF.

Placenta: móviles, usos y significaciones en el centro-sur de Chile / Placenta: motivations, uses, and meanings in south central Chile

RESUMEN Se analizan los móviles, usos y significaciones atribuidos a las placentas por mujeres y hombres en el centro-sur de Chile, a partir de la implementación de la Norma Técnica 189 del Ministerio de Salud, que permite a las personas solicitar y disponer de sus placentas con posterioridad al parto en recintos hospitalarios. A través de una mirada etnográfica acerca del tratamiento sociocultural de las placentas, entre julio y noviembre de 2019 se realizaron entrevistas en profundidad con mujeres y sus parejas; se recogieron relatos individuales, así como conversaciones con mujeres y hombres mapuches, habitantes del territorio chileno de la región de La Araucanía, la región Metropolitana y la región de Arica y Parinacota, que habían solicitado la placenta. El artículo se enfoca en cuatro casos que dan cuenta de la presencia de diversas prácticas y conocimientos en torno a la placenta, estableciendo su inscripción en marcos socioculturales, territoriales y políticos, espirituales y religiosos, según la pertenencia sociocultural de los actores. Como conclusión, se contrastan los casos relevando tanto diferencias como similitudes y se proyectan algunos desafíos derivados de los hallazgos.

ABSTRACT Motivations, uses, and meanings given to the placenta by women and men in south central Chile are analyzed, following the implementation of Technical Standard 189 by the Ministry of Health, which allowed people to request their placentas after giving birth on hospital grounds. From an ethnographic approach to the sociocultural uses of placentas, in-depth interviews were carried out with women and their partners between July and November 2019; individual narratives were recorded, as well as conversations between Mapuche women and men who had requested their placenta in three Chilean regions (Araucania, Metropolitan, and Arica and Parinacota). This article focuses on four cases that illustrate the diversity of practices and knowledge surrounding the placenta - inscribed in sociocultural, territorial, political, spiritual, and religious frameworks - according to actors' sociocultural origins. To conclude, the cases are compared in order to highlight both similarities and differences, and some challenges derived from the findings are considered.

Estudio multicéntrico de incidencia y determinantes de COVID-19 en médicos de Argentina / Multicenter study of COVID-19 incidence and determinants in Argentinian physicians

Resumen Introducción: La información sobre COVID en médicos es limitada. Su conocimiento permitiría implementar acciones para reducir su impacto. El objetivo general fue determinar la incidencia de infección por SARS-CoV-2 en médicos de instituciones de salud de Argentina, sus características y factores aso ciados. Materiales y Métodos: Se realizó un estudio multicéntrico de cohorte prospectiva/retrospectiva con estudio de casos-controles anidado. Se incluyeron médicos activos al inicio de la pandemia no exceptuados por riesgo. Se estimó incidencia de casos confirmados. Se compararon factores asociados en casos y controles y se creó un modelo de regresión logística con las variables significativas del análisis bivariado. Resultados: Se incluyeron 343 médicos con COVID de 8 centros. La incidencia de la enfermedad fue de 12.1% y la de ausentismo global relacionado a COVID, de 34.1%. El 70% de los contactos estrechos fueron laborales. En el análisis multivariado de casos y controles, la residencia en la Ciudad Autónoma de Buenos Aires (OR 0.19, p = 0.01), el trabajo en áreas de alto riesgo (OR 0.22, p = 0.01) y vehículo individual (OR 0.34, p = 0.03) redujeron el riesgo de COVID. El odds de enfermar aumentó 4.6 veces (p = 0.02) por cada aislamiento por contacto estrecho. Discusión: El riesgo de enfermar aumentó considerablemente con cada aislamiento por contacto estrecho. La residencia en Ciudad Autónoma, el traslado en vehículo individual y el trabajo en áreas de alto riesgo lo redujeron. Dada la alta frecuencia de contactos estrechos en el ámbito laboral recomendamos reforzar las medidas de prevención en áreas de descanso y no COVID.

Abstract Background: Information about COVID infection in physicians is limited. This knowledge would allow the implementation of actions to reduce its impact. The objective was determining the incidence of SARS-CoV-2 infection in physicians from health institutions in Argentina, its characteristics, and associated factors. Methods: We conducted a multicenter prospective / retrospective cohort study with nested case-control study. Physicians active at the beginning of the pandemic were included, those on leave due to risk factors were excluded. The incidence of confirmed cases was estimated. We conducted bivariate analyses with various factors and used those significant in a logistic regression. Results: Three hundred and forty three physicians with COVID-infection from 8 centers were included. The incidence of disease was 12.1% and that of global absenteeism related to COVID, 34.1%. Almost 70% of close contacts were work-related. In the multivariate analysis living in Autonomous City of Buenos Aires (CABA) (OR 0.19, p = 0.01), working in high-risk areas (OR 0.22, p = 0.01) and individual transportation (OR 0, 34, p = 0.03) reduced the risk of COVID. The odds of infection increased 5.6 times (p = 0.02) for each close contact isolation. Discussion: The number of close contact isolation increased considerably the risk of infection. Living in Buenos Aires City, individual transpor tation and working in high-risk areas reduced it. Given the high frequency of close contact in the workplace, we strongly recommend the reinforcement of prevention measures in rest areas and non-COVID-wards.

[Mycoplasma pneumoniae meningoencephalitis in a young adult]. / Meningoencefalitis por Mycoplasma pneumoniae en un adulto joven.

Mycoplasma pneumoniae infections have extrapulmonary complications that involve the nervous system. The neurologic manifestations are diverse. Although the prognosis is usually favorable, the patients can undergo severe permanent sequelae. We present a young female adult with acute meningoencephalitis as a complication of a lower respiratory infection, which followed a benign course without neurologic sequelae.

[Cervical aspergillosis with dissemination to the central nervous system: Case reports and review of the literature]. / Aspergilosis cervical con diseminación al sistema nervioso central. Presentación de un caso y revisión de bibliografía.

BACKGROUND: Invasive aspergillosis (IA) of the central nervous system (CNS) is an uncommon condition that usually occurs in immunocompromised patients. This illness can manifest as meningitis, or as a micotic aneurism, stroke or abscess. The infection affects the CNS either primarily or, more often, secondarily via blood dissemination from a distant focus, and has a poor prognosis. We present a patient with IA primarily affecting the cervical bones, with later spread into the brain. CASE DESCRIPTION: A 25-year old male was receiving chemotherapy for acute lymphocytic leukemia when he developed pneumonitis secondary to methotrexate and was started on corticosteroids. He subsequently developed cervicalgia, prompting a needle biopsy of the fourth vertebrae, after which a diagnosis of osteomyelitis was made. Even though the biopsy culture was negative, empirical antibiotics were initiated. A parietal lobe lesion was treated surgically months later after the patient presented with three episodes of transient aphasia. After A. fumigatus grew in culture, the patient's antibiotic regimen was changed to treat the specific agent with a good response. CONCLUSION: IA must be considered a possibility whenever an immunocompromised patient presents with a new brain lesion. These lesions require surgical evacuation, a procedure that allows for diagnostic confirmation and enhances prognosis. Appropriate anti-fungal therapy must be started as soon as the diagnosis is confirmed. In addition, the patient's neurological exam must be repeated and images obtained periodically to monitor treatment and detect possible recurrences.

Distribution of deoxynivalenol in wheat, wheat flour, bran, and gluten, and variability associated with the test procedure.

Analytical data obtained on deoxynivalenol (DON) concentration in naturally contaminated wheat during processing in an industrial mill were statistically analyzed, and the distribution functions of DON concentration in lots of wheat, bran, wheat flour, and gluten were estimated. The analytical method had acceptable precision (HORRAT 0.25-0.32) for each test sample. The total variance combined sampling, sample preparation, and analytical variances were 0.188, 0.033, 0.42, and 0.0014 ppm2 for wheat, 1.93; flour, 0.99; bran, 4.68; and gluten, 0.29, respectively. The distribution function of DON contamination presented an asymmetric tail for high values of concentration in wheat grains and wheat flour; in bran it seemed to be bimodal with 2 separated peaks of different concentrations; in gluten the normal distribution function gave a reasonably good fit to empirical data. The function eta(c) = -In(-Inp), where p (c) is the cumulative distribution function was linear with c in the so-called extreme-value type I distribution and could be fitted by a cubic polynomial in c in the distributions determined for all the products. This variability and distributional information contributes to the design of better sampling plans in order to reduce the total variability and to estimate errors in the evaluation of DON concentration in lots of wheat and wheat products.