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For the Caatinga vegetation, it has not yet been definitively established which adaptive strategies best define the functional groups of woody plants and which syndromes emerge from the relationships between functional traits to achieve success in a semi-arid tropical region. To fill some of these gaps, we analyzed a specific set of characteristics that make up the LHS scheme of the plant ecological strategy (leaf-heigh-seed). The LHS scheme captures the functional niche of plants regarding the functional traits specific leaf area (SLA), plant height (HE), and seed mass (SM). We associate wood density (WD) to this scheme because this trait is a key feature for the identification of functional strategies in seasonally dry vegetation such as the Caatinga. We measured these characteristics in eight woody species and classified them according to their leaf phenology into deciduous and evergreen. The experiment was carried out between December 2017 and November 2018 in Caatinga areas located in the municipality of Barra de Santana, PB, a semiarid region of Brazil. Using cluster analysis, principal component analysis (PCA) and Pearson correlation analyses, we found significant relations between SLA and SM, and HE and WD. The SLA was the main predictor of plant strategy in the Caatinga. According to this characteristic, we identified two functional groups: species with a low SLA and species with a high SLA. We also recognized differences between deciduous and evergreen species based on the same trait. The traits measured, which represent the axes of the plant ecological strategy scheme LHS and wood density, are efficient in the discrimination of functional groups in the Brazilian semiarid. These groups relate to leaf phenology of woody species in this vegetation.

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OBJECTIVE: We report the development and validation of a combined DNA/RNA next-generation sequencing (NGS) platform to improve the evaluation of pancreatic cysts. BACKGROUND AND AIMS: Despite a multidisciplinary approach, pancreatic cyst classification, such as a cystic precursor neoplasm, and the detection of high-grade dysplasia and early adenocarcinoma (advanced neoplasia) can be challenging. NGS of preoperative pancreatic cyst fluid improves the clinical evaluation of pancreatic cysts, but the recent identification of novel genomic alterations necessitates the creation of a comprehensive panel and the development of a genomic classifier to integrate the complex molecular results. METHODS: An updated and unique 74-gene DNA/RNA-targeted NGS panel (PancreaSeq Genomic Classifier) was created to evaluate 5 classes of genomic alterations to include gene mutations (e.g., KRAS, GNAS, etc.), gene fusions and gene expression. Further, CEA mRNA ( CEACAM5 ) was integrated into the assay using RT-qPCR. Separate multi-institutional cohorts for training (n=108) and validation (n=77) were tested, and diagnostic performance was compared to clinical, imaging, cytopathologic, and guideline data. RESULTS: Upon creation of a genomic classifier system, PancreaSeq GC yielded a 95% sensitivity and 100% specificity for a cystic precursor neoplasm, and the sensitivity and specificity for advanced neoplasia were 82% and 100%, respectively. Associated symptoms, cyst size, duct dilatation, a mural nodule, increasing cyst size, and malignant cytopathology had lower sensitivities (41-59%) and lower specificities (56-96%) for advanced neoplasia. This test also increased the sensitivity of current pancreatic cyst guidelines (IAP/Fukuoka and AGA) by >10% and maintained their inherent specificity. CONCLUSIONS: PancreaSeq GC was not only accurate in predicting pancreatic cyst type and advanced neoplasia but also improved the sensitivity of current pancreatic cyst guidelines.

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BACKGROUND: Previous studies have reported healthcare disparities in the Texas-Mexico border population. Our aim was to evaluate treatment utilization and oncologic outcomes of colon cancer patients in this vulnerable population. METHODS: Patients with localized and regional colon cancer (CC) were identified in the Texas Cancer Registry (1995-2016). Clinicopathological data, hospital factors, receipt of optimal treatment, and overall survival (OS) were compared between Texas-Mexico Border (TMB) and the Non-Texas-Mexico Border (NTMB) cohorts. Multivariable analysis was performed to identify risk factors associated with decreased survival. RESULTS: We identified 43,557 patients with localized/regional CC (9% TMB and 91% NTMB). TMB patients were more likely to be Hispanic (73% versus 13%), less likely to have private insurance (13% versus 21%), were more often treated at safety net hospitals (82% versus 22%) and less likely at ACS-CoC accredited hospitals (32% versus 57%). TMB patients were more likely to receive suboptimal treatment (21% versus 16%) and had a lower median OS for localized (8.58 versus 9.58 y) and regional colon cancer (5.75 versus 6.18 y, all P < 0.001). In multivariable analysis, TMB status was not associated with worse OS. Factors associated with worse survival included receipt of suboptimal treatment, Medicare/insured status, and treatment in safety net and non-accredited ACS-CoC hospitals (all P < 0.001) CONCLUSIONS: While TMB CC patients had worse OS, TMB status itself was not found to be a risk factor for decreased survival. This survival disparity is likely associated with higher rate of suboptimal treatment, Medicare/Uninsured status, and decreased access to ACS-CoC accredited hospitals.

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Introducción. En neonatología, más del 90 % de las trombosis venosas profundas están asociadas al uso de catéteres. El objetivo del estudio fue determinar la incidencia y los factores de riesgo relacionados con trombosis venosa profunda asociada a catéteres venosos centrales.Población y métodos. Estudio observacional analítico de cohorte prospectivo. Se incluyeron todos los catéteres venosos centrales mediante un muestreo no aleatorio consecutivo. El protocolo de pesquisa incluyó la evaluación clínica diaria y ecografía doppler (7-10 días luego de su colocación y/o a las 72 h de su retiro). Seguimiento: desde la colocación al retiro del catéter, fallecimiento o contrarreferencia del paciente. Se estimó densidad de incidencia cada 1000 días/catéter con sus intervalos de confianza (IC) del 95 % y factores de riesgo mediante análisis multivariado de Cox.Resultados. Se identificó trombosis en 22/264 catéteres. La densidad de incidencia de trombosis fue del 5,33 ‰ días/catéter (IC 95 %: 3,34-8,07). La cirugía cardiovascular y el uso de catéteres distintos a los epicutáneos resultaron ser factores de riesgo independientes para trombosis [Hazard Ratio: (3,8 [IC 95 %: 1,6-9] y 2,75 [IC 95 %: 1,17-6,45]).Conclusiones. La incidencia de trombosis venosa profunda asociada a catéteres venosos centrales fue de 5,33 cada 1000 días/catéter. El antecedente de procedimientos quirúrgicos cardiovasculares y el uso de catéteres distintos a los epicutáneos se asociaron con mayor riesgo de la complicación.

Introduction. In neonatology, more than 90 % of deep vein thromboses are related to catheter use. The objective of this study was to determine the incidence and risk factors associated with central venous catheter-related deep vein thrombosis.Population and methods. Observational and analytical study conducted in a prospective cohort. All central venous catheters were included using consecutive, non-random sampling. The screening protocol included a daily clinical examination and a Doppler ultrasound (7-10 days after insertion and/or 72 h after removal). Follow-up: from catheter insertion to catheter removal, death or patient counter-referral. The incidence density rate per 1000 catheter-days was estimated with its corresponding 95 % confidence intervals (CIs), and risk factors, using Cox multivariate analysis.Results. Thrombosis was identified in 22/264 catheters. The incidence density rate of thrombosis was 5.33 ‰ catheter-days (95 % CI: 3.34-8.07). Cardiovascular surgery and and the use of central catheters others than peripherally inserted ones, were independent risk factors for thrombosis (hazard ratio: 3.8 [95 % CI: 1.6-9] and 2.75 [95 % CI: 1.17-6.45]).Conclusions. The incidence of central venous catheter-related deep vein thrombosis was 5.33 per 1000 catheter-days. A history of cardiovascular surgical procedures and and the use of central catheters others than peripherally inserted ones, were associated with a higher risk of this complication.

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INTRODUCTION: In neonatology, more than 90 % of deep vein thromboses are related to catheter use. The objective of this study was to determine the incidence and risk factors associated with central venous catheter-related deep vein thrombosis. POPULATION AND METHODS: Observational and analytical study conducted in a prospective cohort. All central venous catheters were included using consecutive, non-random sampling. The screening protocol included a daily clinical examination and a Doppler ultrasound (7-10 days after insertion and/or 72 h after removal). Follow-up: from catheter insertion to catheter removal, death or patient counter-referral. The incidence density rate per 1000 catheter-days was estimated with its corresponding 95 % confidence intervals (CIs), and risk factors, using Cox multivariate analysis. RESULTS: Thrombosis was identified in 22/264 catheters. The incidence density rate of thrombosis was 5.33 ‰ catheter-days (95 % CI: 3.34-8.07). Cardiovascular surgery and and the use of central catheters others than peripherally inserted ones, were independent risk factors for thrombosis (hazard ratio: 3.8 [95 % CI: 1.6-9] and 2.75 [95 % CI: 1.17-6.45]). CONCLUSIONS: The incidence of central venous catheter-related deep vein thrombosis was 5.33 per 1000 catheter-days. A history of cardiovascular surgical procedures and and the use of central catheters others than peripherally inserted ones, were associated with a higher risk of this complication.

Introducción. En neonatología, más del 90 % de las trombosis venosas profundas están asociadas al uso de catéteres. El objetivo del estudio fue determinar la incidencia y los factores de riesgo relacionados con trombosis venosa profunda asociada a catéteres venosos centrales. Población y métodos. Estudio observacional analítico de cohorte prospectivo. Se incluyeron todos los catéteres venosos centrales mediante un muestreo no aleatorio consecutivo. El protocolo de pesquisa incluyó la evaluación clínica diaria y ecografía doppler (7-10 días luego de su colocación y/o a las 72 h de su retiro). Seguimiento: desde la colocación al retiro del catéter, fallecimiento o contrarreferencia del paciente. Se estimó densidad de incidencia cada 1000 días/catéter con sus intervalos de confianza (IC) del 95 % y factores de riesgo mediante análisis multivariado de Cox. Resultados. Se identificó trombosis en 22/264 catéteres. La densidad de incidencia de trombosis fue del 5,33 ‰ días/catéter (IC 95 %: 3,34-8,07). La cirugía cardiovascular y el uso de catéteres distintos a los epicutáneos resultaron ser factores de riesgo independientes para trombosis [Hazard Ratio: (3,8 [IC 95 %: 1,6-9] y 2,75 [IC 95 %: 1,17-6,45]). Conclusiones. La incidencia de trombosis venosa profunda asociada a catéteres venosos centrales fue de 5,33 cada 1000 días/catéter. El antecedente de procedimientos quirúrgicos cardiovasculares y el uso de catéteres distintos a los epicutáneos se asociaron con mayor riesgo de la complicación.

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Extended-spectrum ß-lactamases (ESBLs)-producing Enterobacteriaceae have been classified as critical priority pathogens by the World Health Organization (WHO). We have conducted a microbiological and genomic surveillance study, in order to investigate the occurrence and features of antibiotic-resistant bacteria in wild birds admitted to a wildlife rescue and rehabilitation centre in Chile. This study reports for the first time the occurrence of highly virulent ESBL-producing Escherichia coli and Salmonella enterica serovar Infantis in wild owls inhabiting the Southern Cone of America. Genomic analysis revealed a wide resistome (for antibiotics, heavy metals and disinfectants) among international lineages of E. coli belonging to ST345 and ST2705, and S. Infantis ST32, producing CTX-M-8 or CTX-M-65 ESBLs. On the other hand, wide virulome was associated with a highly virulent behaviour in the Galleria mellonella infection model. Worryingly, all these lineages have been previously reported in humans, supporting that wide resistome and virulome could be contributing to rapid adaptation and dissemination of these clones at the human-animal-environment interface. In summary, wild owls can constitute environmental reservoirs of international clones of ESBL (CTX-M)-producing E. coli and S. Infantis carrying a wide resistome and virulome, in the Southern Cone of America, with potential risks to human, animal and environmental health.

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O presente trabalho teve por objetivo avaliar a influência do tipo de parto sobre a transferência de imunidade passiva e de alguns constituintes séricos de cordeiros recém-nascidos, alimentados naturalmente com colostro materno, criados no semiárido paraibano em sistema extensivo. Foram utilizados 34 cordeiros clinicamente sadios, da raça Santa Inês, os quais foram identificados e pesados imediatamente após o nascimento e separados em dois grupos experimentais com 17 animais cada. O grupo PS (nove machos e oito fêmeas) formado por animais nascidos de partos simples e o grupo PG (seis machos e onze fêmeas) formado por cordeiros nascidos de partos gemelares. A ingestão de colostro se deu de forma natural e voluntária em suas respectivas mães. Foram coletados 10 mL de sangue de cada animal, mediante punção da veia jugular, em tubos siliconizados a vácuo, 48 horas após o nascimento. Após centrifugação, as alíquotas de soro foram separadas e permaneceram congeladas a -15°C até o momento das análises. Para o estudo comparativo dos constituintes séricos, foram constituídos dois grupos experimentais distribuídos em um delineamento inteiramente casualizado, no esquema fatorial 2x2 (tipo de parto e sexo). Os dados obtidos foram submetidos à análise de variância, cujas médias foram comparadas pelo teste de Tukey a 5%. Foram determinadas as atividades séricas das enzimas aspartato aminotransferase (AST) e gamaglutamiltransferase (GGT) e as concentrações séricas de proteína total, albumina, ureia, creatinina, cálcio, fósforo e magnésio, utilizando-se conjuntos de reagentes comerciais e as leituras das amostras em espectrofotômetro automático. As atividades séricas de AST, GGT e as concentrações séricas de proteína total, albumina e globulinas dos cordeiros dos grupos PS e PG não foram influenciadas pelo tipo de gestação e sexo. A partir da concentração sérica de proteína total, verificou-se falha de transferência de imunidade passiva (FTIP) nos cordeiros do grupo PG, utilizando-se o valor 5,0g/dL como ponto de corte. Com exceção do cálcio, as concentrações séricas da ureia, creatinina, fósforo e magnésio apresentaram o mesmo padrão de comportamento. Embora esses constituintes não tenham apresentado diferença significativa entre os grupos estudados e o sexo, pôde-se observar valores mais elevados nos animais nascidos de partos simples, sugerindo que a ausência de concorrência pela ingestão voluntária de colostro materno pode ter sido o fator determinante. Pode-se concluir que cordeiros Santa Inês nascidos de partos gemelares e criados extensivamente no semiárido paraibano apresentam falha na transferência de imunidade passiva e alterações/diminuições marcantes nos teores séricos de alguns constituintes bioquímicos, suscitando a necessidade de interferência humana nestes casos.(AU)

This study is concerned with an evaluation of the influence of mode of birth on the transfer of passive immunity and some serum constituents to newborn lambs, naturally fed with colostrum, breed in the semiarid region of the State of Paraiba (Brazil) on an extensive system. Thirty-four clinically healthy Santa Ines lambs were employed, identified and weighted immediately after birth, and divided into two experimental groups of seventeen animals each. The PS group (nine males and eight females) included lambs born of single pregnancies and the PG group (six males and eleven females) comprised of lambs born of twin pregnancies. The colostrum intake occurred naturally and voluntarily at their mothers. Forty-eight hours after birth, 10 mL of blood were collected in siliconized tubes from each animal by puncture of the jugular vein, and maintained under vacuum. After centrifugation, aliquots of sera were separated and kept frozen at -15°C until analyzed. For the comparative study of serum constituents, two experimental groups were formed, distributed in a completely randomized lineation, 2x2 factorial (type of birth and sex). The data were subjected to analysis of variance, whose means were compared by Tukey test at 5%. The serum activities of AST and GGT, and the total protein serum, albumin, urea, creatinine, calcium, phosphorus and magnesium concentrations were determined by using sets of commercial reagents; the samples were read by an automatic spectrophotometer. The serum activities of AST, GGT and serum concentrations of total protein, albumin and globulins of the PS and PG lambs groups were not influenced by the type of pregnancy and sex. From the serum concentration of total protein, FTIP was found in the lambs of PG group, using the value of 5.0g/dL as the cutoff point. With the exception of calcium, serum concentrations of urea, creatinine, phosphorus and magnesium showed the same pattern. Although these constituents did not showed significant differences between groups and sex, higher values were observed in animals born of single pregnancies, suggesting that the absence of competition for the voluntary ingestion of colostrum may have been the determining factor. It can be concluded that lambs born twin deliveries and breed extensively in the semiarid region of the State of Paraiba failed to transfer passive immunity and showed significant reduction in serum levels of some biochemical constituents, indicating the need for human interference in these cases.(AU)

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O presente trabalho teve por objetivo avaliar a influência do tipo de parto sobre a transferência de imunidade passiva e de alguns constituintes séricos de cordeiros recém-nascidos, alimentados naturalmente com colostro materno, criados no semiárido paraibano em sistema extensivo. Foram utilizados 34 cordeiros clinicamente sadios, da raça Santa Inês, os quais foram identificados e pesados imediatamente após o nascimento e separados em dois grupos experimentais com 17 animais cada. O grupo PS (nove machos e oito fêmeas) formado por animais nascidos de partos simples e o grupo PG (seis machos e onze fêmeas) formado por cordeiros nascidos de partos gemelares. A ingestão de colostro se deu de forma natural e voluntária em suas respectivas mães. Foram coletados 10 mL de sangue de cada animal, mediante punção da veia jugular, em tubos siliconizados a vácuo, 48 horas após o nascimento. Após centrifugação, as alíquotas de soro foram separadas e permaneceram congeladas a -15°C até o momento das análises. Para o estudo comparativo dos constituintes séricos, foram constituídos dois grupos experimentais distribuídos em um delineamento inteiramente casualizado, no esquema fatorial 2x2 (tipo de parto e sexo). Os dados obtidos foram submetidos à análise de variância, cujas médias foram comparadas pelo teste de Tukey a 5%. Foram determinadas as atividades séricas das enzimas aspartato aminotransferase (AST) e gamaglutamiltransferase (GGT) e as concentrações séricas de proteína total, albumina, ureia, creatinina, cálcio, fósforo e magnésio, utilizando-se conjuntos de reagentes comerciais e as leituras das amostras em espectrofotômetro automático. As atividades séricas de AST, GGT e as concentrações séricas de proteína total, albumina e globulinas dos cordeiros dos grupos PS e PG não foram influenciadas pelo tipo de gestação e sexo...(AU)

This study is concerned with an evaluation of the influence of mode of birth on the transfer of passive immunity and some serum constituents to newborn lambs, naturally fed with colostrum, breed in the semiarid region of the State of Paraiba (Brazil) on an extensive system. Thirty-four clinically healthy Santa Ines lambs were employed, identified and weighted immediately after birth, and divided into two experimental groups of seventeen animals each. The PS group (nine males and eight females) included lambs born of single pregnancies and the PG group (six males and eleven females) comprised of lambs born of twin pregnancies. The colostrum intake occurred naturally and voluntarily at their mothers. Forty-eight hours after birth, 10 mL of blood were collected in siliconized tubes from each animal by puncture of the jugular vein, and maintained under vacuum. After centrifugation, aliquots of sera were separated and kept frozen at -15°C until analyzed. For the comparative study of serum constituents, two experimental groups were formed, distributed in a completely randomized lineation, 2x2 factorial (type of birth and sex). The data were subjected to analysis of variance, whose means were compared by Tukey test at 5%. The serum activities of AST and GGT, and the total protein serum, albumin, urea, creatinine, calcium, phosphorus and magnesium concentrations were determined by using sets of commercial reagents; the samples were read by an automatic spectrophotometer. The serum activities of AST, GGT and serum concentrations of total protein, albumin and globulins of the PS and PG lambs groups were not influenced by the type of pregnancy and sex. From the serum concentration of total protein, FTIP was found in the lambs of PG group, using the value of 5.0g/dL as the cutoff point. With the exception of calcium, serum concentrations of urea, creatinine, phosphorus and magnesium showed the same pattern...(AU)

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ABSTRACT: This study is concerned with an evaluation of the influence of mode of birth on the transfer of passive immunity and some serum constituents to newborn lambs, naturally fed with colostrum, breed in the semiarid region of the State of Paraiba (Brazil) on an extensive system. Thirty-four clinically healthy Santa Ines lambs were employed, identified and weighted immediately after birth, and divided into two experimental groups of seventeen animals each. The PS group (nine males and eight females) included lambs born of single pregnancies and the PG group (six males and eleven females) comprised of lambs born of twin pregnancies. The colostrum intake occurred naturally and voluntarily at their mothers. Forty-eight hours after birth, 10 mL of blood were collected in siliconized tubes from each animal by puncture of the jugular vein, and maintained under vacuum. After centrifugation, aliquots of sera were separated and kept frozen at -15°C until analyzed. For the comparative study of serum constituents, two experimental groups were formed, distributed in a completely randomized lineation, 2x2 factorial (type of birth and sex). The data were subjected to analysis of variance, whose means were compared by Tukey test at 5%. The serum activities of AST and GGT, and the total protein serum, albumin, urea, creatinine, calcium, phosphorus and magnesium concentrations were determined by using sets of commercial reagents; the samples were read by an automatic spectrophotometer. The serum activities of AST, GGT and serum concentrations of total protein, albumin and globulins of the PS and PG lambs groups were not influenced by the type of pregnancy and sex. From the serum concentration of total protein, FTIP was found in the lambs of PG group, using the value of 5.0g/dL as the cutoff point. With the exception of calcium, serum concentrations of urea, creatinine, phosphorus and magnesium showed the same pattern. Although these constituents did not showed significant differences between groups and sex, higher values were observed in animals born of single pregnancies, suggesting that the absence of competition for the voluntary ingestion of colostrum may have been the determining factor. It can be concluded that lambs born twin deliveries and breed extensively in the semiarid region of the State of Paraiba failed to transfer passive immunity and showed significant reduction in serum levels of some biochemical constituents, indicating the need for human interference in these cases.

RESUMO: O presente trabalho teve por objetivo avaliar a influência do tipo de parto sobre a transferência de imunidade passiva e de alguns constituintes séricos de cordeiros recém-nascidos, alimentados naturalmente com colostro materno, criados no semiárido paraibano em sistema extensivo. Foram utilizados 34 cordeiros clinicamente sadios, da raça Santa Inês, os quais foram identificados e pesados imediatamente após o nascimento e separados em dois grupos experimentais com 17 animais cada. O grupo PS (nove machos e oito fêmeas) formado por animais nascidos de partos simples e o grupo PG (seis machos e onze fêmeas) formado por cordeiros nascidos de partos gemelares. A ingestão de colostro se deu de forma natural e voluntária em suas respectivas mães. Foram coletados 10 mL de sangue de cada animal, mediante punção da veia jugular, em tubos siliconizados a vácuo, 48 horas após o nascimento. Após centrifugação, as alíquotas de soro foram separadas e permaneceram congeladas a -15°C até o momento das análises. Para o estudo comparativo dos constituintes séricos, foram constituídos dois grupos experimentais distribuídos em um delineamento inteiramente casualizado, no esquema fatorial 2x2 (tipo de parto e sexo). Os dados obtidos foram submetidos à análise de variância, cujas médias foram comparadas pelo teste de Tukey a 5%. Foram determinadas as atividades séricas das enzimas aspartato aminotransferase (AST) e gamaglutamiltransferase (GGT) e as concentrações séricas de proteína total, albumina, ureia, creatinina, cálcio, fósforo e magnésio, utilizando-se conjuntos de reagentes comerciais e as leituras das amostras em espectrofotômetro automático. As atividades séricas de AST, GGT e as concentrações séricas de proteína total, albumina e globulinas dos cordeiros dos grupos PS e PG não foram influenciadas pelo tipo de gestação e sexo. A partir da concentração sérica de proteína total, verificou-se falha de transferência de imunidade passiva (FTIP) nos cordeiros do grupo PG, utilizando-se o valor 5,0g/dL como ponto de corte. Com exceção do cálcio, as concentrações séricas da ureia, creatinina, fósforo e magnésio apresentaram o mesmo padrão de comportamento. Embora esses constituintes não tenham apresentado diferença significativa entre os grupos estudados e o sexo, pôde-se observar valores mais elevados nos animais nascidos de partos simples, sugerindo que a ausência de concorrência pela ingestão voluntária de colostro materno pode ter sido o fator determinante. Pode-se concluir que cordeiros Santa Inês nascidos de partos gemelares e criados extensivamente no semiárido paraibano apresentam falha na transferência de imunidade passiva e alterações/diminuições marcantes nos teores séricos de alguns constituintes bioquímicos, suscitando a necessidade de interferência humana nestes casos.

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Hippidions were equids with very distinctive anatomical features. They lived in South America 2.5 million years ago (Ma) until their extinction approximately 10 000 years ago. The evolutionary origin of the three known Hippidion morphospecies is still disputed. Based on palaeontological data, Hippidion could have diverged from the lineage leading to modern equids before 10 Ma. In contrast, a much later divergence date, with Hippidion nesting within modern equids, was indicated by partial ancient mitochondrial DNA sequences. Here, we characterized eight Hippidion complete mitochondrial genomes at 3.4-386.3-fold coverage using target-enrichment capture and next-generation sequencing. Our dataset reveals that the two morphospecies sequenced (H. saldiasi and H. principale) formed a monophyletic clade, basal to extant and extinct Equus lineages. This contrasts with previous genetic analyses and supports Hippidion as a distinct genus, in agreement with palaeontological models. We date the Hippidion split from Equus at 5.6-6.5 Ma, suggesting an early divergence in North America prior to the colonization of South America, after the formation of the Panamanian Isthmus 3.5 Ma and the Great American Biotic Interchange.

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