Ecohydrological Modeling in Agroecosystems: Examples and Challenges

Human societies are increasingly altering the water and biogeochemical cycles to both improve ecosystem productivity and reduce risks associated with the unpredictable variability of climatic drivers. These alterations, however, often cause large negative environmental consequences, raising the question as to how societies can ensure a sustainable use of natural resources for the future. Here we discuss how ecohydrological modeling may address these broad questions with special attention to agroecosystems. The challenges related to modeling the two‐way interaction between society and environment are illustrated by means of a dynamical model in which soil and water quality supports the growth of human society but is also degraded by excessive pressure, leading to critical transitions and sustained societal growth‐collapse cycles. We then focus on the coupled dynamics of soil water and solutes (nutrients or contaminants), emphasizing the modeling challenges, presented by the strong nonlinearities in the soil and plant system and the unpredictable hydroclimatic forcing, that need to be overcome to quantitatively analyze problems of soil water sustainability in both natural and agricultural ecosystems. We discuss applications of this framework to problems of irrigation, soil salinization, and fertilization and emphasize how optimal solutions for large‐scale, long‐term planning of soil and water resources in agroecosystems under uncertainty could be provided by methods from stochastic control, informed by physically and mathematically sound descriptions of ecohydrological and biogeochemical interactions

Role of the small integrin-binding ligand N-linked glycoprotein (SIBLING), bone sialoprotein (BSP) in bone development and remodeling.

14 pagesInternational audienceMembers of the “small, integrin binding ligand, N-linked glycoprotein” (SIBLING) family, which have both mineral binding and cell binding (integrins) abilities, appear as potent regulators of bone mineralisation and remodeling. Among these, osteopontin (OPN) and bone sialoprotein (BSP) are highly expressed in early bone. Gene knockout of OPN results in increased mineralisation and a resorption defect making mutant mice unable to respond to such challenges as hindlimb unloading. We recently published the phenotype of mice with a knockout of BSP (BSP-/-). We showed that BSP-/- mice are smaller than the wild type counterpart, with a lower bone-formation rate but a higher trabecular volume at 4 month, due to impaired resorption. Lack of BSP results in slower bone repair in a cortical defect model, but does not prevent bone loss due to unloading, in contrast to OPN knockout. These results highlight the specificity of BSP roles in the bone context, as well as the nonredundancy of function of SIBLING family members in skeletal biology

Salmonellosis in wild birds and its relationship with the infection in finishing pigs

The potential relationship between Salmonella infection in wild birds and pigs was investigated. Feces from pigs, wild birds, and bird droppings or other environmental samples from 25 finishing farms were cultured for Salmonella isolation. In 17 (68%) farms Salmonella was isolated. Out of 57 Salmonella isolates found, 32 (56.1%) were Typhimurium. In 6 (24%) farms the same Salmonella serotype was isolated from samples from different origins and similar AR and PFGE patterns were found, which would support the existence of a transmission cycle of Salmonella infection between birds and pigs in this area. Preventing bird access to farm premises is highly recommended

Estudio serológico de la infección por Salmonella spp. en cerdos de engorde del Noreste de España y factores de riesgo asociados

The results of a serological survey carried out in northeastern Spain to estimate the seroprevalence to Salmonella spp. and to determine potential risk factors are presented. Sera were obtained from farms submitting serum samples to the Regional Diagnostic Laboratory (RDL) for the diagnosis of other infectious diseases included within official eradication/surveillance programs, and farm data collected through a questionnaire. Out of 6,182 pig sera (217 farms) analyzed 1,219 (19.7%) were positive (optical density, OD ≥ 40%). More than 70% of the herds presented ≥ 1 seropositive animal indicating that salmonellosis was widespread. In a multivariable logistic mixed regression model seroprevalence was associated with farms where birds were visible inside the fattening units (OR = 2.1; 95% CI: 1.3-3.2) or that shared workers with other pig farms (OR = 2.5; 95% CI: 1.4-4.7). Seropositivity also increased when farmers used footwear exclusive for the farm (OR = 3.1; 95% CI: 1.3-7.3) or pigs were fed mostly with pellets (OR = 1.7; 95% CI: 1.1-2.6). It was also higher during the fall and winter months. The presence of a changing room and shower in the farm was negatively associated with it (OR = 0.5; 95% CI: 0.3-0.8). Most risk factors could be mitigated through strict hygiene and biosecurity measures, but the high (> 40%) within-herd seroprevalence observed in many herds may challenge the capacity of intervention of animal health authorities.Se presentan los resultados de un estudio serológico realizado en explotaciones porcinas del Noreste de España para estimar la seroprevalencia frente a Salmonella spp. y determinar posibles factores de riesgo asociados. Los sueros se obtuvieron a partir de aquellos enviados por las explotaciones al Laboratorio Regional de Diagnóstico para el diagnóstico de otras enfermedades infecciosas sometidas a erradicación/vigilancia oficial, y los datos sobre las explotaciones se recogieron mediante un cuestionario. De un total de 6.182 sueros de cerdo (217 granjas) analizados 1.219 (19,7%) resultaron positivos (densidad óptica, DO ≥ 40%). Más del 70% de los rebaños presentaron al menos un animal positivo, indicando que la salmonelosis está ampliamente distribuida en la región. Según un modelo multivariable mixto de regresión logística, la seroprevalencia se asoció con granjas en las cuales se veían aves en el interior de las naves (OR = 2,1; IC 95%: 1,3-3,2) y también con granjas que compartían trabajadores (OR = 2,5; IC 95%: 1,4-4,7). Se observó que la seropositividad se incrementaba cuando los trabajadores usaban botas exclusivas en la explotación (OR = 3,1; IC 95%: 1,3-7,3) o al alimentar a los cerdos principalmente con alimento granulado (OR = 1,7; IC 95%: 1,1-2,6). La seroprevalencia también fue superior durante los meses de otoño e invierno. La existencia en las granjas de vestuarios y duchas para el personal se asoció negativamente con la seroprevalencia (OR = 0,5; IC 95%: 0,3-0,8). La mayoría de los factores de riesgo podrían controlarse a través de estrictas medidas de higiene y bioseguridad, pero el gran número de rebaños que presentaron alta seroprevalencia (> 40%) puede poner a prueba la capacidad de intervención de las autoridades sanitarias oficiales

Serological characterization of Salmonella spp. infection in finishing pigs from NE Spain

The seroprevalence of salmonella spp. In finishing pigs in Aragón (NE of Spain) and the potential factors associated with it were assessed. Serum samples were collected directly from the Regional Diagnostic Laboratory (RDL). Only farms submitting a minimum of 30 serum samples to the RDL were included, i.e. exporting and farrow-to-finish farms, and those in the last stages of the Aujezsky\u27s disease eradication program

The addition of galacto-oligosaccharides on the feed for the control of salmonellosis in fattening pigs

Prebiotics that block intestinal harmful bacteria and stimulate both the activity of beneficial bacteria and the animal immune system may help in controlling pig salmonellosis. We added a galacto-oligosaccharide (Salmosan®) on the diet of pigs during the whole period of fattening to assess its potential effect on the prevalence of Salmonella spp. In a first trial 56 pigs from a small fattening unit (fewer than 200 animals) were fed with a diet where Salmosan® (0.5 kg/Ton of feed) was added, while the rest of the animals were fed with the same feed without the galacto-oligosaccharide

Characterization of Salmonella enterica serovars Tyhimurium and 4,5,[12]:i:- isolated from pigs and pig environmental-related sources in the NE of Spain

A total of 117 Salmonella Typhimurium and 59 monophasic Salmonella Typhimurium (S. 4,[5],12:i:-) strains isolated from pig, wild bird, rodent, and farm environmental samples were characterized by phage typing, antibiotic susceptibility testing and Multiple-Locus Variable-Number Tandem Repeat Analysis (MLVA) in order to evaluate their phenotypic and genetic relatedness. In S. 4,[5],12:i:- the most prevalent phage types were U311 (40.7%) and DT195 (22%) which did not correspond with the so-called Spanish clone, and generally showed a different resistant pattern (ASSuT). Antibiotic resistance was found in 85.8% of the isolates, with 94.1% of them displaying multidrug resistance (MDR). MLVA identified 92 different profiles, six of them shared by both serovars. The Minimum Spanning Tree showed one major cluster that included 95% of the S. 4,[5],12:i:- isolates, which came from different animal sources, geographic locations and time periods, suggesting high clonality among those Salmonella strains and the ability to spread among pig farms. Phenotypically, isolates of S. 4,[5],12:i:- were closer to European strains than to the well-characterized Spanish clone. The spread of these new strains of S. 4,[5],12:i:- would have been likely favoured by the important pig trade between this Spanish region and other European countries

Defecting or not defecting: how to "read" human behavior during cooperative games by EEG measurements

Understanding the neural mechanisms responsible for human social interactions is difficult, since the brain activities of two or more individuals have to be examined simultaneously and correlated with the observed social patterns. We introduce the concept of hyper-brain network, a connectivity pattern representing at once the information flow among the cortical regions of a single brain as well as the relations among the areas of two distinct brains. Graph analysis of hyper-brain networks constructed from the EEG scanning of 26 couples of individuals playing the Iterated Prisoner's Dilemma reveals the possibility to predict non-cooperative interactions during the decision-making phase. The hyper-brain networks of two-defector couples have significantly less inter-brain links and overall higher modularity - i.e. the tendency to form two separate subgraphs - than couples playing cooperative or tit-for-tat strategies. The decision to defect can be "read" in advance by evaluating the changes of connectivity pattern in the hyper-brain network

First Salmonella spp. prevalence study in pigs and pork products from the province of Córdoba, Argentine

The study of the prevalence of Salmonella spp. in the pig and pork production chain is important to reduce the risk of spreading this pathogen into the human population. The aim of this study was to estimate the prevalence of Salmonella spp. in pigs and pork products from Córdoba. Mesenteric lymph nodes samples from 580 finishing pigs from different pig farms , and 420 samples (83 batches) of fresh pork products (the so-called “chorizo fresco de cerdo”) from different retailers were analyzed. ISO 6579:2002 standard protocol was used for Salmonella isolation. Prevalence of Salmonella spp. in finishing pigs in Córdoba was 41.5% (95%CI 37.6%- 45.6%). According to pig´s origin the province was split in North, Central and South region. The prevalence observed in each region was 49.5%, 43.0% and 36.0% respectively. The significantly higher prevalence observed in the North may be associated with the precarious conditions of the pig production sector in that area, compared to the better pig producing practices in the southern region. Prevalence of Salmonella spp. in fresh pork products was 17.4% (95%CI 15.8%-23.4%). Based on the Argentine Food Codex criteria, 34/83 (40.9%) of the analyzed batches should be rejected given the presence Salmonella spp. positive. In addition, total coliforms were also analyzed on these pork samples following national legislation and 42 (63.0%) of the batches should have been rejected according to coliform total count. Overall, only 13% of the batches fulfilled both criteria for acceptance. In conclusion, the high prevalence of Salmonella spp. in pig farms and of Salmonella spp. and coliforms in these type of pork products suggested important safety breakdowns along the pig production and pork elaboration processes. An important effort should be done to reach suitable hygienic and sanitary standards for pig and pork production in the province of Córdoba