How do goats "read" 2D-images of familiar and unfamiliar conspecifics?

To study individual recognition in animals, discrimination tasks are often conducted by presenting 2D images of real conspecifics. However, animals may discriminate the images merely as visual stimulus combinations without establishing referential relationships to the individuals depicted. In the current study, we investigated whether goats are able to discriminate photos of familiar and unfamiliar conspecifics, whether they not only process the photos as visual stimuli, but also understand them as virtual copies of real conspecifics and whether they grasp the concept of familiarity. Using a computer-controlled learning device, in three tests, goats of two experimental groups (A and B) had to discriminate portrait (Te1), profile (Te2) or headless body photos (Te3) of conspecifics. Tests were presented as 4-choice tasks, with one photo from Group A (rewarded) plus three photos from Group B (distractors). That is, the rewarded photo was familiar to Group A, but unfamiliar to Group B. Finally, in a reversal test (Te4) we reversed this principle. The goats learned the discriminations in Te1 to Te3 within two (Te1 and Te2) and three training days (Te3), respectively, and they needed between 91 [CL (66, 126)] and 174 [CL (126, 241)] trials to reach the learning criterion, with no statistically significant differences between the groups. In Te4, in contrast, the animals took 403 [Group A; CL (291, 557)] and 385 [Group B; CL (286, 519)] trials, respectively, to learn the task. The lack of spontaneous preferences for the photo of the familiar conspecific in the pretests of Te1 to Te3 in Group A, as well as the lack of differences in the number of trials to learn the discriminations between both groups, do not at first glance suggest that the goats established a correspondence between real conspecifics and their 2D representations. However, the higher number of trials in Te4 suggests that both groups formed the learning rule of choosing either the known (Group A) or the unknown goat (Group B) over the course of Te1 to Te3 and then failed after the rule was reversed, providing evidence that goats can associate 2D photos of conspecifics with real animals.

Exploring cocoa bean fermentation mechanisms by kinetic modelling.

Compared with other fermentation processes in food industry, cocoa bean fermentation is uncontrolled and not standardized. A detailed mechanistic understanding can therefore be relevant for cocoa bean quality control. Starting from an existing mathematical model of cocoa bean fermentation we analyse five additional biochemical mechanisms derived from the literature. These mechanisms, when added to the baseline model either in isolation or in combination, were evaluated in terms of their capacity to describe experimental data. In total, we evaluated 32 model variants on 23 fermentation datasets. We interpret the results from two perspectives: (1) success of the potential mechanism, (2) discrimination of fermentation protocols based on estimated parameters. The former provides insight in the fermentation process itself. The latter opens an avenue towards reverse-engineering empirical conditions from model parameters. We find support for two mechanisms debated in the literature: consumption of fructose by lactic acid bacteria and production of acetic acid by yeast. Furthermore, we provide evidence that model parameters are sensitive to differences in the cultivar, temperature control and usage of steel tanks compared with wooden boxes. Our results show that mathematical modelling can provide an alternative to standard chemical fingerprinting in the interpretation of fermentation data.

Monitoring the changes in low molecular weight carbohydrates in cocoa beans during spontaneous fermentation: A chemometric and kinetic approach.

The low molecular weight carbohydrate (LMWC) profile has recently been investigated, showing considerable changes between fermented and unfermented cocoa beans. These differences are a consequence of the fermentation process, which is considered a crucial step in chocolate production. During fermentation, LMWC are involved in Maillard reaction, a crucial reaction for the development of aroma and taste precursors. However, there is a lack of information related to LMWC changes and of contextualization with changes in other physicochemical parameters (pH and dry matter) during spontaneous fermentation. The different approaches employed in this manuscript have allowed the identification of a sequential degradation of tetra-, tri- and disaccharides, as well as an increase in the monosaccharide content during fermentation. Moreover, a correlation was determined between some LMWC and physicochemical parameters. Besides that, the chemometric approach identified the fermentation period ranging between 48 and 96 h as determinant to produce noticeable changes in unfermented beans based on the indicators evaluated. Furthermore, different kinetic parameteres (reaction order, observed reaction rates (kobs) and half-life values (t1/2)) of different LMWC were determined, showing differences between them. The results showed in this manuscript provide unprecedented mechanistic details of spontaneous cocoa fermentation.

Dietary Oily Fish Intake and Frailty. A Population-Based Study in Frequent Fish Consumers Living in Rural Coastal Ecuador (the Atahualpa Project).

Oily fish are recommended as part of a healthy diet due to their high content of long-chain omega-3 polyunsaturated fatty acids (ω-3 PUFAs), proteins, and other nutrients. There is preliminary evidence of beneficial effects of ω-3 PUFAs in the prevention of sarcopenia (a major component of frailty). In this study, we aimed to assess the relationship between dietary oily fish intake and a measure of frailty - the Edmonton Frail Scale (EFS) score - in community-dwelling older adults living in rural coastal Ecuador. A total of 363 Atahualpa residents were enrolled. The mean fish servings per week were 8.8 ± 5.2 and mean EFS score was 5 ± 2.8 points. A linear regression model showed no association between the amount of oily fish intake and EFS scores. However, an interaction model, with participants stratified according to their median age and fish intake in quintiles, showed a significant effect for both variables on the EFS score (ß coefficient = 0.104; 95% C.I.: 0.003-0.206; p = 0.044). At the lowest quintile of fish intake, younger individuals have lower EFS scores than their older counterparts. As the consumption of oily fish increases, mean EFS scores margins were found to be progressively reduced in subjects aged 60-69 years but were largely unaffected in persons aged ≥70 years. It appears that oily fish intake has a positive effect on the frailty status of younger subjects but is superseded by the effects of age in the older population.

Cognitive decline is not influenced by the marital status or living arrangements in community-dwelling adults living in a rural setting. A population-based prospective cohort study.

Little is known on factors influencing cognitive decline in rural communities. Using the Atahualpa Project cohort, we aimed to assess whether the marital status or living arrangements influenced cognitive decline in community-dwelling adults living in an Ecuadorian rural village. The study included 629 Atahualpa residents aged ≥40 years who had a follow-up Montreal Cognitive Assessment (MoCA) repeated at least one year after baseline. Multivariate longitudinal linear models were fitted to assess differences between the marital status and living arrangements and cognitive decline (as the outcome). A total of 411 participants were married. The remaining 218 were either single, divorced or widowed (191 of them lived with family members and the others lived alone). Enrolled individuals contributed 2088.4 person-years of follow-up (mean: 3.3 ±â€¯1.1 years). The mean baseline MoCA was 22.1 ±â€¯4.5 points and the follow-up MoCA was 20.6 ±â€¯4.8 points (p = 0.001). Overall, 394 (63%) individuals had lower MoCA scores at follow-up. A fully-adjusted longitudinal linear model showed no differences in MoCA decline across married and non-married individuals (ß: -0.15; 95% C.I.: -0.55 - 0.26; p = 0.477). When the subset of non-married individuals was taken into account for analyses, multivariate longitudinal linear models showed no differences in the severity of cognitive decline across individuals living alone versus those living with family members (ß: 0.28; 95% C.I.: -0.68 - 1.24; p = 0.572). In this study, the marital status or living arrangements had no influence on cognitive decline in the follow-up.

Supratentorial arachnoid cysts and seizures/epilepsy: A population study in community dwellers aged ≥20 years.

Literature on the association between arachnoid cysts and seizures/epilepsy is inconsistent, and most series have been flawed due to recruitment bias. In this study, we aimed to assess the prevalence of supratentorial arachnoid cysts (SACs) in Atahualpa residents aged ≥20 years, and to estimate whether these lesions were associated with seizures/epilepsy. A total of 1157 individuals were included. Computed tomography revealed SACs in 25 individuals (2.2%). Most had middle cranial fossa SACs (n = 19). Recurrent nonprovoked seizures were diagnosed in 28 individuals and a single seizure in 4. Only 1 of 25 (4%) individuals with SACs had seizures/epilepsy as opposed to 31 of 1132 (2.7%) who did not have SACs (P = 0.508). A logistic regression model showed no association between SACs and seizures/epilepsy, after taking into account the effect of relevant confounders (odds ratio [OR] 1.71; 95% confidence interval [95% CI] 0.22-13.3; P = 0.607). This study provides evidence of lack of association between SACs and seizures/epilepsy.

Lack Of Association Between The Friedman's Tongue Position Type IV And Obstructive Sleep Apnea In Older Adults Of Amerindian Ancestry / Ausencia De Asociación Entre La Posición De La Lengua Tipo IV De Friedman Y Apnea Obstructiva De Sueño En Adultos Mayores Con Ancestro Amerindio

ABSTRACT Background: The burden of obstructive sleep apnea (OSA) in rural settings is unknown. In these regions, devices needed for OSA diagnosis are not available, and mass screening with field instruments may be complicated due to cross-cultural factors and illiteracy. The association between the Friedman's tongue position (FTP) and OSA has been assessed in people from different ethnic groups but not in Amerindians. Objective: We aimed to assess whether a FTP type IV is associated with OSA severity and with the apnea-hypopnea index (AHI) in community-dwelling older adults of Amerindian ancestry living in rural Ecuador. Methods: A total of 201 Atahualpa residents aged ≥60 years, who underwent tongue position assessment, brain MRI, and polysomnography were included. After adjusting for relevant confounders, ordinal logistic regression models were fitted to assess the association between the presence of a FTP type IV and OSA categories (none, mild, and moderate-to-severe), and generalized linear models with a Gaussian link were fitted to assess the association between the presence of a FTP type IV and the continuous AHI. Results: A FTP type IV was identified in 153 (76%) individuals, the mean AHI per hour was 11.9 ± 12.4, and 49 (24%) individuals had moderate-to-severe OSA, 88 (44%) had mild OSA, and the remaining 64 (32%) had no OSA. Fully-adjusted generalized linear models showed no independent association between the investigated exposure and the AHI (β: 0.09; 95% C.I.: -1.56 - 1.76; p=0.909). Likewise, ordinal logistic regression models showed no independent association between the investigated exposure and categories of OSA (β: 0.42; 95% C.I.: -0.47 - 1.31; p=0.357). Conclusion: A FTP type IV is not associated with the AHI or the severity of OSA in this population of Amerindians. This lack of association could be related to phenotypic characteristics of people from this ethnic group (mostly their elliptic hard palate).

RESUMEN Antecedentes: Se desconoce la prevalencia de la apnea obstructiva del sueño (AOS) en entornos rurales. En esas regiones, los equipos necesarios para el diagnóstico de AOS no están disponibles, y la detección de AOS con instrumentos de campo puede ser complicada debido a factores interculturales y analfabetismo. La asociación entre la posición de la lengua de Friedman (FTP) y AOS se ha evaluado en personas de diferentes grupos étnicos, pero no en Amerindios. Objetivo: Evaluar si al tipo IV de FTP está asociado con la severidad de la AOS y con el índice de apnea-hipopnea (IAH) en adultos mayores que viven en una comunidad de ascendencia Amerindia en zonas rurales de Ecuador. Métodos: Se incluyeron 201 residentes de Atahualpa de edad ≥60 años, que fueron sometidos a evaluación de la posición de la lengua, resonancia magnética cerebral y polisomnografía. Después de ajustar por factores de confusión relevantes, modelos de regresión logística ordinal evaluaron la probable asociación entre la presencia de un FTP tipo IV y las categorías AOS (ninguna, leve y moderada a grave), y se ajustaron modelos lineales generalizados con un enlace gaussiano para evaluar la asociación entre la presencia de un FTP tipo IV y el IAH continuo. Resultados: Se identificó un tipo IV de FTP en 153 (76%) individuos, el IAH promedio por hora fue de 11.9 ± 12.4 y 49 (24%) individuos tenían AOS de moderada a grave, 88 (44%) tenían AOS leve. y los 64 restantes (32%) no tenían AOS. Los modelos lineales generalizados, ajustados por confusores, no mostraron una asociación independiente entre la exposición investigada y el IAH (β: 0.09; 95% C.I.: -1.56 - 1.76; p = 0.909). Del mismo modo, los modelos de regresión logística ordinal no mostraron una asociación independiente entre la exposición investigada y las categorías de AOS (β: 0,42; 95% C.I.: -0,47 - 1.31; p = 0,357). Conclusión: El tipo IV de FTP no está asociado con el IAH o la gravedad de la AOS en esta población de Amerindios. Esta falta de asociación podría estar relacionada con las características fenotípicas de las personas de este grupo étnico (principalmente su paladar óseo de tipo elíptico).

The Association between Calcified Neurocysticercosis and Cognitive Performance: A Case-Control Study Nested to a Population-Based Cohort.

Mechanisms implicated in the association between neurocysticercosis (NCC) and cognitive impairment remain unknown. Atahualpa residents aged ≥ 40 years with calcified NCC were identified as case patients and paired 1:1 to age- and gender-matched controls. The selection process generated 79 pairs. Cognitive performance was measured by the Montreal Cognitive Assessment (MoCA). A conditional logistic regression model revealed no differences in MoCA scores across case patients and controls, after adjusting for education, epilepsy, depression, and hippocampal atrophy. The single covariate remaining significant was hippocampal atrophy. When participants were stratified according to this covariate, linear models showed lower MoCA scores among case patients (but not controls) with hippocampal atrophy. In a fully adjusted linear regression model, age remained as the single covariate explaining cognitive impairment among NCC patients. This study demonstrates an association between hippocampal atrophy and poor cognitive performance among patients with calcified NCC, most likely attributable to the effect of age.

Sleep quality correlates with the carotid intima-media thickness in stroke-free community-dwelling adults living in rural Ecuador. The Atahualpa Project.

BACKGROUND/OBJECTIVES: Evidence of an association between sleep disorders and extracranial atherosclerosis is limited and has not been studied in remote rural settings, where living conditions and cardiovascular risk factors are different than in urban centers. We assessed the relationship between the carotid intima-media thickness (cIMT) and sleep quality in stroke-free individuals aged ≥40 years living in rural Ecuador. METHODS: Applying a population-based study design, participants underwent face-to-face interviews using the Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality, and sonographic examinations for measurement of the carotid intima-media thickness (cIMT). The association between the cIMT and sleep quality (as the dependent variable) was assessed by means of generalized linear models, adjusted for relevant confounders. RESULTS: The mean age of 561 participants was 60.4 ± 12.6 years (58% women). The mean PSQI was 4.6 ± 2.2 points. Of those, 79 (14%) individuals had an increased cIMT (>1 mm). A model adjusted for demographics showed a significant association between increased cIMT and the PSQI score (ß: 0.602; 95% C.I.: 0.027-1.177; p = 0.040). This relationship was reduced when cardiovascular risk factors were added to the model (ß: 0.514; 95% C.I.: -0.072 - 1.101; p = 0.086). When the model was adjusted for demographics and psychological distress, the association between increased cIMT and the PSQI score became significant (ß: 0.573; 95% C.I.: 0.013-1.133; p = 0.045). In addition, both symptoms of depression (p = 0.032) and anxiety (p < 0.001) remained independently significant. CONCLUSIONS: This study shows an association between increased cIMT and the PSQI score, which is, at least, partly mediated by manifestations of psychological distress.

The value of the Evans and bicaudate indices for predicting poor cognitive performance and central atrophy. Results from the Atahualpa Project.

Recent studies suggested that both the Evans index (EI) and the bicaudate index (BI) are predictive markers of central atrophy and, as such, have been inversely associated with cognitive performance. This study investigated whether the EI and the BI (independently and combined) correlated with the MoCA score by means of generalized linear models adjusted for relevant confounders. Using a population-based design, 618 Atahualpa residents aged ≥40 underwent a head CT and MoCA testing. Both, the EI and the BI, were independently calculated by two readers, and a mean of the two values for each index was calculated for analysis. Generalized linear models showed inverse significant relationships between the EI and the BI with the MoCA score (p = 0.034, and p < 0.001, respectively). When both predictive variables (EI and BI) were included in a generalized linear model adjusted for all confounders, the BI remained significantly associated with the MoCA score (p = 0.004) but the EI did not (p = 0.677). This study shows that only the BI has and explanatory power outside the endogenous construct (central atrophy) for which both, the BI and the EI are part and parcel of.

Clinical and neuroimaging risk factors for cognitive decline in community-dwelling older adults living in rural Ecuador. A population-based prospective cohort study.

OBJECTIVE: There is limited information on factors influencing cognitive decline in rural settings from low- and middle-income countries. Using the Atahualpa Project cohort, we aimed to assess the burden of cognitive decline in older adults living in a rural Ecuadorian village. METHODS: The study included Atahualpa residents aged greater than or equal to 60 years who had a follow-up Montreal Cognitive Assessment (MoCA) repeated at least 1 year after baseline. MoCA decline was assessed by multivariable longitudinal linear models, adjusted for demographics, days between MoCA tests, cardiovascular risk factors, and neuroimaging signatures of structural brain damage. RESULTS: We included 252 individuals who contributed 923.7 person-years of follow-up (mean: 3.7 ± 0.7 years). The mean baseline MoCA was 19.5 ± 4.5 points, and the follow-up MoCA was 18.1 ± 4.9 points (P = 0.001). Overall, 154 individuals (61%) had lower MoCA scores at follow-up. The best fitted longitudinal linear model showed a decline of follow-up MoCA from baseline (ß: 0.14; 95% CI, 0.0-0.21; P < 0.001). High glucose levels, global cortical atrophy, and white matter hyperintensities were independently and significantly associated with greater MoCA decline. CONCLUSION: This study provides evidence of cognitive decline in older adults living in a rural setting. Main targets for prevention should include glucose control and the control of factors that are deleterious for the development of cortical atrophy and white matter hyperintensities.

Arterial stiffness and total cerebral small vessel disease score in community-dwelling older adults: Results from the Atahualpa Project.

Information on the association between arterial stiffness and cerebral small vessel disease (cSVD) is limited and confined to white and Asian populations. More regional information is needed to confirm this association in different ethnic groups. Using the Atahualpa Project cohort, we aimed to assess whether the aortic pulse wave velocity (PWV) is associated with the total cSVD score, as well as with each of the neuroimaging signatures of cSVD, in a population of Amerindians living in rural Ecuador. Atahualpa residents aged ⩾ 60 years were offered a brain magnetic resonance imaging scan (MRI) and aortic PWV determination. An ordinal logistic regression model, adjusted for demographics and cardiovascular risk factors, was constructed to predict the total cSVD score by levels of aortic PWV. The association between the neuroimaging signatures of cSVD and the aortic PWV was assessed by adjusted logistic regression models. Of 437 candidates, 303 (69%) underwent a brain MRI and aortic PWV determinations. The total cSVD score was 0 points in 65% of individuals, 1 point in 18%, 2 points in 11%, and 3-4 points in 6%. The mean aortic PWV was 10.4 ± 1.8 m/s, which increased from 9.8 ± 1.2 to 12.3 ± 1.8 m/s in individuals with a cSVD score of 0 and 3-4, respectively ( p < 0.001). An ordinal logistic regression model showed significant association between the PWV and the cSVD score. A change of one unit of the aortic PWV increased the odds of having a higher total cSVD score by 1.73 (95% CI: 1.28-2.35; p < 0.001). In addition, individual neuroimaging signatures of cSVD, with the exception of lacunar infarcts, were associated with the aortic PWV. This study shows a significant association between the aortic PWV and total cSVD score and most of its individual components in older Amerindians.

Influence of Frailty on Cognitive Decline: A Population-Based Cohort Study in Rural Ecuador.

OBJECTIVE: To assess the influence of frailty on cognitive decline. DESIGN: Population-based prospective cohort study. SETTINGS/PARTICIPANTS: Community-dwelling older adults living in a rural Ecuadorian village, fulfilling the following criteria: age ≥60 years at baseline Montreal Cognitive Assessment (MoCA) and frailty assessment, a baseline brain magnetic resonance imaging, and a follow-up MoCA performed at least 12 months after the baseline. MEASURES: Frailty was evaluated by the Edmonton Frailty Scale (EFS) and cognitive performance by MoCA. The relationship between baseline EFS and MoCA decline was assessed by longitudinal linear and fractional polynomial models, adjusted for relevant confounders. The score of the cognitive component of the EFS was subtracted, and an alternative fractional polynomial model was fitted to settle the impact of such cognitive question on the model. RESULTS: A total of 252 individuals, contributing 923.7 person-years of follow-up (mean: 3.7 ± 0.7 years) were included. The mean EFS score was 4.7 ± 2.5 points. The mean baseline MoCA score was 19.5 ± 4.5 points, and that of the follow-up MoCA was 18.1 ± 4.9 points (P = .001). Overall, 154 (61%) individuals had lower MoCA scores in the follow-up. The best fitted longitudinal linear model showed association between baseline EFS score and MoCA decline (P = .027). There was a continuous increase in MoCA decline in persons with an EFS ≥7 points (nonlinear relationship). Fractional polynomials explained the effect of the EFS on MoCA decline. For the complete EFS score, the ß coefficient was 2.43 (95% confidence interval 1.22-3.63). For the effect of the EFS (without its cognitive component) on MoCA decline, the relationship was still significant (ß 4.86; 95% confidence interval 2.6-7.13). CONCLUSIONS/IMPLICATIONS: Over a 3.7-year period, 61% of older adults living in Atahualpa experienced cognitive decline. Such decline was significantly associated with frailty status at baseline. Region-specific risk factors influencing this relationship should be further studied to reduce its burden in rural settings.

Head-up and body positioning might impair dynamic cerebral autoregulation in patients with silent cerebral small vessel disease. Protocol and operational definitions / El posicionamiento elevado de cabeza y cuerpo podrían afectar la autorregulación cerebral dinámica en pacientes con enfermedad silente de pequeño vaso cerebral. Protocolo y definiciones operacionales

ABSTRACT Background: Cerebral autoregulation (CA) is the ability of intracranial vessels to maintain a constant cerebral blood flow (CBF) during changes of cerebral perfusion pressure (CPP) related to fluctuations in blood pressure, postural changes or increased metabolic demands. It has been suggested that individuals with silent cerebral small vessel disease (SVD) may have impaired CA, but information is inconclusive. We describe the protocol of a study aimed to assess the association between white matter hyperintensities (WMH) of presumed vascular origin and poor dynamic CA, and to determine the effects of head-up and body positioning in patients with this condition. Methods: Using a case-control study design, we will assess the relationship between severity of WMH and dynamic CA, measured by continuous transcranial Doppler assessment of CBF velocities in the middle cerebral arteries (MCAs) combined with beat-to-beat blood pressure monitoring. Dynamic CA will be analyzed by calculating the mean flow index as the ratio of median arterial pressure and mean flow velocities of the MCAs. Participants will be categorized as case-patients if the MRI shows moderate-to-severe WMH. For every case-patient, an age- and sex-matched healthy individual with no neuroimaging evidence of SVD will be selected as a control. Comment: This study will assess whether head-up and body positioning impairs dynamic CA in the setting of diffuse subcortical damage related to SVD, providing further evidence on the importance of CPP in maintaining the CBF. If positive, the study will provide evidence favoring the stop of aggressive hypertensive therapy or interventions promoting orthostatic hypotension to reduce the risk of further ischemic brain damage in these cases.

RESUMEN Antecedentes: La autorregulación cerebral (CA) es la capacidad de los vasos cerebrales de mantener un flujo sanguíneo constante durante cambios en la presión de perfusión cerebral (PPC) relacionados con fluctuaciones de la presión arterial, cambios posturales o aumento de las demandas metabólicas. Se ha sugerido que las personas con enfermedad de pequeño vaso cerebral pueden tener CA deteriorada, pero la información no es concluyente. Describimos el protocolo de un estudio cuyo objetivo es evaluar la asociación entre hiperintensidades de substancia blanca y CA dinámica deficiente, para determinar los efectos del posicionamiento de cabeza y cuerpo en estos pacientes. Métodos: Utilizando un diseño de caso-control, evaluaremos la relación entre la severidad de las hiperintensidades de substancia blanca y la CA dinámica, mediante Doppler transcraneal continuo de las velocidades de flujo en las arterias cerebrales medias (ACM) combinadas con monitoreo de la presión arterial. La CA dinámica se analizará calculando el índice de flujo medio y la relación entre la presión arterial media y las velocidades medias de flujo de las ACM. Los participantes se clasificarán como casos si la IRM muestra hiperintensidades de substancia blanca. Para cada caso, se seleccionará a un individuo sin evidencia de enfermedad de pequeño vaso como control. Comentario: Este estudio evaluará si el posicionamiento de la cabeza hacia arriba afecta la CA dinámica en el contexto del daño subcortical difuso relacionado con enfermedad de pequeño vaso, proporcionando evidencia adicional sobre la importancia de la PPC en el mantenimiento del flujo en estos sujetos. El estudio proporcionará evidencia sobre el uso de terapia hipertensiva agresiva o intervenciones que promueven la hipotensión ortostática para reducir el riesgo de daño cerebral isquémico.

A mathematical model of cocoa bean fermentation.

Cocoa bean fermentation relies on the sequential activation of several microbial populations, triggering a temporal pattern of biochemical transformations. Understanding this complex process is of tremendous importance as it is known to form the precursors of the resulting chocolate's flavour and taste. At the same time, cocoa bean fermentation is one of the least controlled processes in the food industry. Here, a quantitative model of cocoa bean fermentation is constructed based on available microbiological and biochemical knowledge. The model is formulated as a system of coupled ordinary differential equations with two distinct types of state variables: (i) metabolite concentrations of glucose, fructose, ethanol, lactic acid and acetic acid and (ii) population sizes of yeast, lactic acid bacteria and acetic acid bacteria. We demonstrate that the model can quantitatively describe existing fermentation time series and that the estimated parameters, obtained by a Bayesian framework, can be used to extract and interpret differences in environmental conditions. The proposed model is a valuable tool towards a mechanistic understanding of this complex biochemical process, and can serve as a starting point for hypothesis testing of new systemic adjustments. In addition to providing the first quantitative mathematical model of cocoa bean fermentation, the purpose of our investigation is to show how differences in estimated parameter values for two experiments allow us to deduce differences in experimental conditions.

The Association between Earlobe Crease (Frank's Sign) and Abnormal Ankle-Brachial Index Determination Is Related to Age: A Population-Based Study.

BACKGROUND: Information on the association between earlobe crease (ELC) and peripheral artery disease is limited. We assessed this association in community-dwelling older adults. STUDY DESIGN: A total of 294 Atahualpa residents aged ≥60 years were enrolled. ELC were visually identified by two raters. The ankle-brachial index (ABI), used as a surrogate of peripheral artery disease, was categorized using American Heart Association criteria. Using logistic regression and probability models, adjusted for demographics and cardiovascular risk factors, we assessed the relationship between ELC and abnormal ABI determinations, as well as the influence of age on this association. RESULTS: ELC was identified in 141 (48%) individuals, and abnormal ABI determination was carried out in 56 (19%). The association between ELC and abnormal ABI was nonsignificant in logistic regression and probability models with individuals stratified according to their median age. CONCLUSIONS: The association between ELC and abnormal ABI determinations is probably attenuated by the high prevalence of both conditions in older persons. ELC might not be useful for identifying candidates for ABI determination.

The association between earlobe crease (Frank's sign) and cognitive performance is related to age. Results from the Atahualpa Project.

BACKGROUND: Earlobe crease (ELC) has been linked to cardiovascular diseases, but information on its association with cognitive decline is limited. We aimed to assess the association between ELC and cognitive performance in community-dwelling adults living in rural Ecuador. METHODS: Of 863 individuals aged ≥40 years enrolled in the Atahualpa Project, 629 (73%) were included. ELC were visually identified by two independent raters, and cognitive performance was measured by the Montreal Cognitive Assessment (MoCA). Using generalized linear and interaction models, adjusted for demographics, cardiovascular risk factors and edentulism, we assessed the association between ELC and cognitive performance, as well as the influence of age in this association. RESULTS: ELC was present in 246 (39%) individuals, and the mean MoCA score in the entire population was 21.9 ± 4.7 points. A generalized linear model showed no relationship between ELC presence and the MoCA score (p = 0.449). In this model, covariates remaining significant were age (p < 0.001), physical activity (p = 0.014) and edentulism (p < 0.001). When participants were stratified according of quartiles of age, the MoCA score did not differ according to the presence or absence of ELC. Weighted exposure-effect models - using ELC and the MoCA score as the exposure and outcome (respectively) - revealed no association between both variables. CONCLUSIONS: The association between ELC and the MoCA score is mainly related to age. These findings might be explained by the high prevalence of ELC and cognitive decline in older adults.

The relationship between the neck circumference and the carotid intima-media thickness in Amerindians. Potential links to health risks?

The carotid intima media thickness (cIMT) is a predictor of cardiovascular events. The neck circumference (NC) has been investigated as a risk factor for increased cIMT with contradictory results. This study assessed the relationship between NC and cIMT in Atahualpa residents aged ≥40 years who had sonographic examination of carotid arteries (n = 590). We also discussed on potential pathogenetic mechanisms underlying this association. Participants belonged to the Native Ecuadorian (Amerindians) ethnic group. Non-parametric regression models were used to assess the aforementioned relationship, after adjusting for relevant confounders. The mean age of participants was 60.9 ± 12.7 years (58% women). The mean value of the cIMT was 0.85 ± 0.19 mm. The mean NC was 35.8 ± 34 cm. The NC was normally distributed, but the cIMT was not. Mean values of NC and cIMT were significantly greater in men than in women. Non-parametric models showed significant differences in median cIMT values according to quartiles of NC. Predictive cIMT margins increased by quartiles of NC, significantly among individuals in the 1st quartile as compared to the 3rd quartile. In this population of Amerindians, smaller NC is associated with lower values of cIMT. The pattern of this association is different in men than in women. Sex-related differences in cervical fat tissue distribution probably accounted for such differences.

Distribution of Cervicocephalic Atherosclerotic Lesions and Their Correlation with Cardiovascular Risk Factors in a Population of Amerindians. The Atahualpa Project.

BACKGROUND: No information is available on the distribution of cervicocephalic atherosclerosis in Amerindians. We aimed to assess the distribution of these lesions and their correlation with cardiovascular risk factors in Amerindians living in rural Ecuador. METHODS: Atahualpa residents aged ≥40years underwent head CT for assessment of carotid siphon calcifications (CSC) and sonographic examination for measurement of the carotid intima media thickness (cIMT). CSC were used as a surrogate of intracranial atherosclerosis and the cIMT as a surrogate of extracranial atherosclerosis. Linear regression and multinomial logistic regression models were fitted to assess the association between cIMT and CSC, and to evaluate differences in risk factors across individuals with atherosclerosis involving both arterial beds when compared with those with extra- or intracranial atherosclerosis alone, or no atherosclerosis. RESULTS: Of 590 participants, 145 had high calcium content in the carotid siphons and 87 had a cIMT >1mm (25% versus 15%, P < .001). Thirty-eight (7%) individuals had atherosclerosis at both vascular beds, 107 (18%) had intracranial atherosclerosis, and 49 (8%) had extracranial atherosclerosis alone. The cIMT and CSC were independently associated (P = .008). When compared with participants without atherosclerosis, those with atherosclerosis at both vascular beds were older, more often male, hypertensive and diabetic. Subjects with intracranial atherosclerosis alone were older, and those with extracranial atherosclerosis alone reported less physical activity than those without atherosclerosis. CONCLUSION: Intracranial atherosclerosis is more common than extracranial atherosclerosis in Amerindians. Traditional risk factors only explain a minority of cases of cervicocephalic atherosclerosis in this population.

Arterial Stiffness is Independently Associated with Severity of Carotid Siphon Calcifications in Community-Dwelling Older Adults: The Atahualpa Project.

BACKGROUND: Knowledge on the association between arterial stiffness and intracranial atherosclerosis is limited. Here, we aimed to assess whether the aortic pulse wave velocity (PWV)-used as a surrogate of arterial stiffness-might independently predict severity of carotid siphon calcifications (CSCs), used as a marker of atherosclerosis. METHODS: Of 437 Atahualpa residents aged 60 years or older, 300 (69%) underwent head computed tomography (CT) (for CSC assessment), brain magnetic resonance imaging (for identification of neuroimaging signatures of cerebral small vessel disease [SVD]), and aortic PWV determinations (for arterial stiffness estimation). Ordinal logistic regression models were constructed to predict severity of CSC (as the dependent variable) according to levels of aortic PWV after adjusting for demographics, cardiovascular risk factors, and neuroimaging signatures of SVD. RESULTS: Grade 1 CSC were noticed in 120 (40%) subjects, grade 2 in 84 (28%), grade 3 in 73 (24%), and grade 4 in 23 (8%). The mean PWV was 10.4 ± 1.8 m/s, which increased from 9.8 ± 1.3 to 11.1 ± 2.1 m/s in individuals with grades 1 and 4 CSC, respectively (P <.001). The most parsimonious ordinal logistic regression model adjusted for relevant confounders showed a significant association between aortic PWV and severity of CSC. In this model, a change of 1 unit of aortic PWV increased the odds of CSC severity by 1.22 (95% confidence interval 1.07-1.39; P = .004). CONCLUSIONS: The monotonically increased odds of aortic PWV among subjects with different grades of CSC, suggest that aortic PWV may be a marker for identifying candidates for CT screening in the search of CSC.