11 results
56 Dunning-Kruger Effect and Anxiety in a Mexican population
- Natalia L. Acosta, Krissy E. Smith, Tara L. Victor, David H. Hardy, Alberto L. Fernandez, Raymundo Cervantes, Ana Paula P. Quiñones, Carolina G. Castañeda, Jill Razani, Isabel D.C. Muñoz, Daniel W. Lopez-Hernandez
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 841-842
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Objective:
The Dunning-Krueger effect is a cognitive bias where individuals tend to overestimate their abilities in areas where they are less competent. The Cordoba Naming Test (CNT) is a 30-item confrontation naming task. Hardy and Wright (2018) conditionally validated a measure of perceived mental workload called the NASA Task Load Index (NASA-TLX). Researchers reported that workload ratings on the NASA-TLX increased with increased task demands on a cognitive task. Anxiety is known as an emotion that can make an individual more susceptible to develop a mental health condition. We examine if the Dunning-Krueger effect occurs in a Mexican population with and without current symptoms of anxiety and possible factors driving individuals to overestimate their abilities on the CNT. We predicted the abnormal symptoms of anxiety (ASA) group would report better CNT performance, report higher perceived workloads on the CNT, and underperform on the CNT compared to the normal symptoms of anxiety (NSA) group. We also predicted the low-performance group would report better CNT performance, report higher perceived workloads on the CNT, and underperform on the CNT compared to the high-performance group.
Participants and Methods:The sample consisted of 192 Mexican participants with NSA (79 low-performance & 113 high-performance) and 74 Mexican participants with ASA (44 low-performance & 30 high-performance). Participants completed the CNT, NASA-TLX, and the Hospital Anxiety and Depression Scale (HADS) in Spanish. The NASA-TLX was used to evaluate perceived workloads after the completion of the CNT. Meanwhile, the HADS was used to create our anxiety groups. Finally, CNT raw scores were converted into T-scores, which then were averaged to create the following two groups: low-performance (CNT T-Score <50) and high-performance (CNT T-Score 50+). A series of 2x2 ANCOVAs, controlling for gender were used to evaluate CNT performance and perceived workloads.
Results:We found a significant interaction where the low-performance ASA and the high-performance NSA groups demonstrated better CNT performance and reported higher perceived workloads (i.e., performance, temporal demand) on the CNT compared to their respective counterparts (i.e., low-performance NSA & high-performance ASA groups), p's<.05, ηp's2=.02. We found a main effect where the high-performance group outperformed the low-performance group on the CNT and reported lower perceived workloads on the CNT, p's<.05, ηp's2 =.04-.46.
Conclusions:The Dunning-Krueger effect did not occur in our sample. Participants that demonstrated better CNT performance also reported higher perceived workloads regardless of their current symptoms of anxiety. A possible explanation can be our sample's cultural norms of what would be considered as abnormal symptoms of anxiety, is a normal part of life, decreasing the possibilities to experience self-efficacy distoritions. Future studies should investigate whether the Dunning-Kruger effect may be influencing other aspects of cognitive functioning subjectively in Mexicans residing in Mexico and the United States with and without current symptoms of anxiety.
27 Aging Affects Cordoba Naming Test Performance
- Jasman Sidhu, Krithika Sivaramakrishnan, Raymundo Cervantes, Sarah Saravia, Luz Estrada, Dulce Garcia, Alexia Barrio, Isabel D. Munoz, Enrique Lopez, Tara L. Victor, Alberto L. Fernandez, Daniel W. Lopez-Hernandez
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 339-340
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Objective:
The Cordoba Naming Test (CNT) is a 30-item confrontation naming test developed in Argentina. A common confrontation naming task used in the United States is the Boston Naming Test (BNT). Research shows that age affects BNT performance in the 60-item long form. In fact, studies show that scores on confrontation naming tasks increase in childhood and continue to improve until approximately 40 years of age. However, after this period, scores start to subsequently decline, and especially so after 70 years of age. On the other hand, some studies have reported that older adults maintain high BNT performance despite advancing age. To our knowledge, no study has investigated the aging effects of the CNT across various age groups. We expected CNT scores to increase significantly from young adulthood to mid-adulthood and then significantly decline with advancing age.
Participants and Methods:The present study sample consisted of 272 neurologically and psychologically healthy participants with a mean age of 27.06 (SD = 12.21) with 14.29 years of education completed (SD = 2.46). Participants were divided into six different age groups: 18-19-year-old group, 20-29-year-old group, 30-39-year-old group, 40-49-year-old group, 50-59-year-old group, and 60-69-year-old group. All participants consented to voluntary participation and completed the CNT and a comprehensive background questionnaire in English. The CNT consisted of 30 black and white line drawings, ranging from easy to hard difficulty. An ANCOVA, controlling for gender, was used to evaluate CNT performance between the six age groups. We used a threshold of p < .05 for statistical significance.
Results:Results revealed significant group differences between the six age groups on the CNT, p = .000, ηp2 = .14. A post-hoc test revealed that the 30-39-year-old group outperformed the 18-19-year-old, 20-29-yearold, and 60-69-year-old groups on the CNT. Finally, the 40-49-year-old group outperformed the 18-19-year-old and 60-69-year-old groups on the CNT.
Conclusions:As we predicted, participants demonstrated steady improvement in the CNT until the age of 40. However, we found that until the age of 60, CNT performance started to decline significantly. Our data suggests that CNT performance declines significantly at the age of 60 compared to previous research using the BNT. Research shows other demographic variables (e.g., gender, linguistic factors) influence BNT performance. Future investigations on the CNT using a healthy sample should use a multivariate statistical analysis method to help explain influencing factors across aging. This research can have the potential to improve public health to better support and understand individuals from diverse backgrounds.
8 The Dunning-Kruger Effect on a Latinx Population
- Carolina Garza Castaneda, Matthew J. Wright, Raymundo Cervantes, Tara L. Victor, Krissy E. Smith, Chelsea McElwee, Adriana Cuello, Alberto L. Fernandez, Isabel D. C. Munoz, David J. Hardy, Daniel W. Lopez-Hernandez
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 423-424
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Objective:
Individuals tend to overestimate their abilities in areas where they are less competent. This cognitive bias is known as the Dunning-Krueger effect. Research shows that Dunning-Krueger effect occurs in persons with traumatic brain injury and healthy comparison participants. It was suggested by Walker and colleagues (2017) that the deficits in cognitive awareness may be due to brain injury. Confrontational naming tasks (e.g., Boston Naming Test) are used to evaluate language abilities. The Cordoba Naming Test (CNT) is a 30-item confrontational naming task developed to be administered in multiple languages. Hardy and Wright (2018) conditionally validated a measure of perceived mental workload called the NASA Task Load Index (NASA-TLX). They found that workload ratings on the NASA-TLX increased with increased task demands on a cognitive task. The purpose of the present study was to determine whether the Dunning-Kruger effect occurs in a Latinx population and possible factors driving individuals to overestimate their abilities on the CNT. We predicted the low-performance group would report better CNT performance, but underperform on the CNT compared to the high-performance group.
Participants and Methods:The sample consisted of 129 Latinx participants with a mean age of 21.07 (SD = 4.57). Participants were neurologically and psychologically healthy. Our sample was divided into two groups: the low-performance group and the high-performance group. Participants completed the CNT and the NASA-TLX in English. The NASA-TLX examines perceived workload (e.g., performance) and it was used in the present study to evaluate possible factors driving individuals to overestimate their abilities on the CNT. Participants completed the NASA-TLX after completing the CNT. Moreover, the CNT raw scores were averaged to create the following two groups: low-performance (CNT raw score <17) and high-performance (CNT raw score 18+). A series of ANCOVA's, controlling for gender and years of education completed were used to evaluate CNT performance and CNT perceived workloads.
Results:We found the low-performance group reported better performance on the CNT compared to the high-performance, p = .021, np2 = .04. However, the high-performance group outperformed the low-performance group on the CNT, p = .000, np2 = .53. Additionally, results revealed the low-performance group reported higher temporal demand and effort levels on the CNT compared to the high-performance group, p's < .05, nps2 = .05.
Conclusions:As we predicted, the low-performance group overestimated their CNT performance compared to the high-performance group. The current data suggest that the Dunning-Kruger effect occurs in healthy Latinx participants. We also found that temporal demand and effort may be influencing awareness in the low-performance group CNT performance compared to the high-performance group. The present study suggests subjective features on what may be influencing confrontational naming task performance in low-performance individuals more than highperformance individuals on the CNT. Current literature shows that bilingual speakers underperformed on confrontational naming tasks compared to monolingual speakers. Future studies should investigate if the Dunning-Kruger effects Latinx English monolingual speakers compared to Spanish-English bilingual speakers on the CNT.
42 Lexical Retrieval and Acculturation in Generation Z Mexicans
- Yvette D Jesus, Krissy E Smith, Krithika Sivaramakrishnan, Reymundo Cervantes, Tara L Victor, Brittany Heuchert, Dorthy Schmidt, Diana Palacios, Chelsea McElwee, David J Hardy, Enrique Lopez, Alberto L Fernandez, Daniel W Lopez Hernandez
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, p. 453
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Objective:
The Cordoba Naming Test (CNT) is a 30-item lexical retrieval task that was developed to be administered in multiple languages. Research shows that self-identifying Mexicans residing in Mexico outperform self-identifying Mexicans that reside in the United States on the CNT. Studies indicate that the process of acculturation can influence cognitive performance. Previous studies demonstrated that Generation Z individuals (i.e., people born between 1997 and 2012) have underperformed on the CNT compared to Generation Y individuals (i.e., people born between 1981 and 1996). To our knowledge, no study has examined the influence of acculturation on Generation Z Mexicans’ CNT performance. We expected Mexicans residing in Mexico (MRM) to outperform Mexicans residing in the United States on the CNT and to report higher acculturation traits. We also predicted that acculturation would correlate with CNT performance.
Participants and Methods:The present study sample consisted of 285 Generation Z psychologically and neurologically healthy Mexicans with a mean age of 20.32 (SD = 1.60). Participants were divided into three groups: MRM, Mexicans residing in the United States, and Mexican-Americans residing in the United States (MARUS). All participants completed the CNT and acculturation measure in Spanish. Acculturation traits were measured by the Abbreviated Multidimensional Acculturation Scale (AMAS). ANCOVAs were used to evaluate differences in the CNT and AMAS (i.e., Spanish language, Latino competency, Latino identity). Pearson’s correlation coefficient was used to evaluate the relationship between acculturation on CNT performance.
Results:MRM outperformed the Mexicans residing in the United States and MARUS on the CNT, p = .000, np2 = .49. The MRM group reported better Spanish language abilities compared to Mexicans residing in the United States and the MARUS groups, p = .000, np2 = .10. Additionally, MRM reported better Latino competency than the MARUS group, p = .000, np2 = .08. Pearson’s correlation coefficient revealed that the MARUS’s Spanish language abilities impacted CNT performance, p = .000, r = .48. In addition, we found that Latino competency correlated with CNT performance, p’s < .05, r’s = .20-.47, in both the MRM and Mexicans residing in the United States groups. Latino identity did not significantly correlate with CNT performance in any group.
Conclusions:Results confirmed that MRM individuals perform better on the CNT than Mexicans residing in the United States and MARUS. Additionally, we found that several acculturation traits correlated with Mexican groups’ CNT performance. Our research indicates that while all Generation Z individuals of Mexican heritage feel strongly connected to their Latino identity regardless of where they live, MARUS feel less competent in Spanish and Latinx culture than MRM and Mexicans residing in the United States. Future work should further explore these differences for better insight into how acculturative factors influence lexical retrieval performance. Future work with bigger sample sizes can additionally examine CNT performance and acculturation in Generation Z first-generation and non-first-generation Mexicans (e.g., second-generation, third-generation) residing in the United States.
22 Cordoba Naming Test Performance and Acculturation in a Geriatric Population
- Isabel C.D. Muñoz, Krissy E. Smith, Santiago I. Espinoza, Diana M. R. Maqueda, Adriana C. Cuello, Ana Paula Pena, Carolina Garza, Raymundo Cervantes, Jill Razani, Tara L. Victor, David J. Hardy, Alberto L. Fernandez, Natalia Lozano Acosta, Daniel W. Lopez-Hernandez
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 335-336
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Objective:
A commonly used confrontation naming task used in the United States is The Boston Naming Test (BNT). Performance differences has been found in Caucasian and ethnic minorities on the BNT. The Cordoba Naming Test (CNT) is a 30-item confrontation naming task developed in Argentina. Past research has shown acculturation levels can influence cognitive performance. Furthermore, one study evaluated geriatric gender differences on CNT performance in Spanish. Researchers reported that older male participants outperformed female participants on the CNT. To our knowledge, researchers have not evaluated ethnic differences on the CNT using a geriatric sample. The purpose of the present study was to examined CNT performance and acculturation in a Latinx and Caucasian geriatric sample. It was predicted the Caucasian group would outperform the Latinx group on the CNT. Moreover, the Caucasian group would report higher acculturation levels on the Abbreviated Multidimensional Acculturation Scale (AMAS) compared to the Latinx group.
Participants and Methods:The sample consisted of 9 Latinx and 11 Caucasian participants with a mean age of 66.80 (SD =6.10), with an average of 14.30 (SD = 2.00) years of education. All participants were neurologically and psychologically healthy and completed the CNT and the AMAS in English. Acculturation was measured via the AMAS English subscales (i.e., English Language, United States. Identity, United States, Competency). A series of ANCOVAs, controlling for years of education completed and gender, was used to evaluate CNT performance and acculturation.
Results:The ethnic groups were not well demographically matched (i.e., years of education and gender).We found that the Caucasian group outperformed the Latinx group on CNT performance p = .012, ηp 2 = .34. Furthermore, the Caucasian group reported higher acculturation levels (i.e., English Language, United States, Identity, United States, Competency) compared to the Latinx group p’s < .05, ηps2 = .42-.64.
Conclusions:To our knowledge, this is the first study to evaluate CNT performance between ethnic groups with a geriatric sample. As expected the Caucasian group outperformed the Latinx group on the CNT. Also, as expected the Caucasian group reported higher English acculturation levels compared to the Latinx group. Our findings are consistent with past studies showing ethnic differences on confrontational naming performance (i.e., The Boston Naming Test), favoring Caucasians. A possible explanation for group differences could have been linguistic factors (e.g., speaking multiple languages) in our Latinx group. Therefore, since our Latinx group reported lower levels of English Language, United States identity, and United States competency the Latinx group assimilation towards United States culture might of influence their CNT performance. Future studies with different ethnic groups (e.g., African-Americans) and a larger sample size should examine if ethnic differences continue to cross-validate in a geriatric sample.
30 Analyzing Spanish Speakers Cordoba Naming Test Performance
- Raymundo Cervantes, Isabel D.C. Munoz, Estefania J. Aguirre, Natalia Lozano Acosta, Mariam Gomez, Adriana C. Cuello, Krissy E. Smith, Diana I. Palacios Mata, Krithika Sivaramakrishnan, Yvette De Jesus, Santiago I. Espinoza, Diana M. R. Maqueda, David J. Hardy, Tara L. Victor, Alberto L. Fernandez, Daniel W. Lopez-Hernandez
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 443-444
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Objective:
A 30-item confrontation naming test was developed in Argentina for Spanish speakers, The Cordoba Naming Test (CNT). The Boston Naming Test is an established confrontation naming task in the United States. Researchers have used the Boston Naming Test to identify individuals with different clinical pathologies (e.g., Alzheimer’s disease). The current literature on how Spanish speakers across various countries perform on confrontational naming tasks is limited. To our knowledge, one study investigated CNT performance across three Spanish-speaking countries (i.e., Argentina, Mexico, and Guatemala). Investigators found that the Guatemalan group underperformed on the CNT compared to the Argentine and Mexican groups. The purpose of this study was to extend the current literature and investigate CNT performance across five Spanish-speaking countries (i.e., Argentina, Mexico, Guatemala, Colombia, United States). We predicted that the Argentine group would outperform the other Spanish-speaking countries.
Participants and Methods:The present study sample consisted of 502 neurologically and psychologically healthy participants with a mean age of 29.06 (SD = 13.41) with 14.75 years of education completed (SD = 3.01). Participants were divided into five different groups based on their country of birth and current country residency (i.e., United States, Mexico, Guatemala, Argentina, & Colombia). All participants consented to voluntary participation and completed the CNT and a comprehensive background questionnaire in Spanish. The CNT consisted of 30 black and white line drawings, ranging from easy to hard in difficulty. An ANCOVA, controlling for gender, education, and age, was used to evaluate CNT performance between the five Spanish-speaking country groups. Meanwhile, a Bonferroni post-hoc test was utilized to evaluate the significant differences between Spanish-speaking groups. We used a threshold of p < .05 for statistical significance.
Results:Results revealed significant group differences between the five Spanish speaking groups on the CNT, p = .000, np2 = .48. Bonferroni post-hoc test revealed that the United States group significantly underperformed on the CNT compared to all the Spanish-speaking groups. Next, we found the Guatemalan group underperformed on the CNT compared to the Argentinian, Mexican, and Colombian groups. Additionally, we found the Argentinian group outperformed the Mexican, Guatemalan, and United States groups on the CNT. No significant differences were found between the Argentinian group and Colombian group or the Mexican group and Colombian group on the CNT.
Conclusions:As predicted, the Argentinian group outperformed all the Spanish-speaking groups on the CNT except the Colombian group. Additionally, we found that the United States group underperformed on the CNT compared to all the Spanish-speaking groups. A possible explanation is that Spanish is not the official language in the United States compared to the rest of the Spanish-speaking groups. Meanwhile, a possible reason why the Argentinian and Colombian groups demonstrated better CNT performances might have been that it was less culturally sensitive than the United States, Mexican, and Guatemalan groups. Further analysis is needed with bigger sample sizes across other Spanish-speaking countries (e.g., Costa Rica, Chile) to evaluate what variables, if any, are influencing CNT performance.
39 Perceived Workload and Language Order Effects on the Cordoba Naming Test in Spanish-English Bilinguals
- Krissy E. Smith, Isabel D. C. Munoz, Raymundo Cervantes, Andrea R. Preciado, Tara L. Victor, Natalia Garcia, Paula V. Bracho, Enrique Lopez, Alberto L. Fernandez, Yvette De Jesus, Daniel W. Lopez-Hernandez
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 451-452
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Objective:
The Cordoba Naming Test (CNT) is a 30-item confrontation naming task. The administration of the CNT can be administered in multiple languages. Hardy and Wright (2018) conditionally validated a measure of perceived mental workload called the National Aeronautic Space Administration Task Load Index (NASA-TLX). They found that workload ratings on the NASA-TLX increased with increased demands on a cognitive task. Researchers found interactions in a study examining language proficiency and language (i.e., in which the test was administered) on several tasks of the Golden Stroop Test. Their results revealed that unbalanced bilinguals’ best-spoken language showed significantly better results compared to balanced bilinguals’ where language use did not matter. To our knowledge, no study has examined the order effects of Spanish-English bilingual speakers’ CNT performance and perceived workloads when completed in Spanish first compared to English second and vice-versa. We predicted that persons that completed the CNT in English first would demonstrate better performances and report lower perceived workloads on the CNT compared to completing the CNT in Spanish second. In addition, we predicted that persons that completed the CNT in Spanish first would demonstrate worse performance and higher perceived workloads on the CNT compared to completing the CNT in English second.
Participants and Methods:The sample consisted of 62 Spanish-English healthy and neurologically bilingual speakers with a mean age of 19.94 (SD= 3.36). Thirty-seven participants completed the CNT in English first and then in Spanish (English-to-Spanish) and 25 participants completed the CNT in Spanish first and then in English (Spanish-to-English). The NASA-TLX was used to evaluate CNT perceived workloads. All the participants completed the NASA-TLX in English and Spanish after completing the CNT in the language given, respectfully. A series of paired-samples T-Tests were completed to evaluate groups CNT performance and perceived workload.
Results:We found that the English-to-Spanish group performed better on the CNT in English first than completing it in Spanish second, p = .000. We also found that the English-to-Spanish group reported better performance and less mentally demanding on the CNT when it was completed in English first compared to completing it in Spanish second, p’s < .05. Regarding the Spanish-to-English group, we found participants performed worse when they completed the CNT in Spanish first compared to completing the CNT in English second, p = .000. Finally, the Spanish-to-English group reported worse performance completing the CNT in Spanish first, more temporal demanding, and more frustrating compared to completing the CNT in English second, p’s < .05.
Conclusions:As expected, when participants completed the CNT in English, regardless of the order, they performed better and reported lower perceived workloads compared to completing the CNT in Spanish. Our data suggests that language order effect influenced participants CNT performance possibly due to not knowing specific items in Spanish compared to in English. Future studies using larger sample sizes should evaluate language order effects on the CNT in Spanish-English balanced bilingual speakers compared to unbalanced bilingual speakers.
Undernutrition reduces the body weight and testicular size of bucks exposed to long days but not their ability to stimulate reproduction of seasonally anestrous goats
- J. A. Delgadillo, A. Lemière, J. A. Flores, M. Bedos, H. Hernández, J. Vielma, M. Guerrero-Cervantes, L. A. Zarazaga, M. Keller, P. Chemineau
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In semiarid conditions, feed is often scarce and variable with underfeeding being common; these factors can potentially induce fertility reductions in both sexes. Sexually active bucks are able to very efficiently fertilize out-of-season goats, but we do not know whether underfeeding would reduce the ability of bucks to fertilize goats during these periods. Two experiments were conducted to determine (i) testicular size and change of odor intensity of undernourished bucks exposed to long days and (ii) the ability of these bucks to stimulate reproductive activity in seasonally anestrous goats. In experiment 1, bucks (n = 7) were fed 1.5 times the normal maintenance requirements from September to May and formed the well-fed group. Another group of bucks (n = 7) were fed 0.5 times the maintenance requirements and formed the undernourished group. All bucks were subjected to artificially long days from 1 November to 15 January; this period was followed by a natural photoperiod until 30 May. Body weight, scrotal circumference and male odor intensity changes were determined every 2 weeks. In experiment 2, two groups of female goats (n = 26 each) were exposed to well-fed (n = 2) or undernourished bucks (n = 2) on 31 March. Ovulations and pregnancy rates were determined by transrectal ultrasonography. In experiment 1, a treatment by time interaction was detected for BW, scrotal circumference and odor intensity changes (P < 0.001). The BWs of well-fed bucks were greater than those of the undernourished bucks from October to May (P < 0.01), as were the scrotal circumferences from December to March (P < 0.05) and odor intensities from February to May (P < 0.05). In experiment 2, the proportions of females that ovulated at least once (100% v. 96%) or those that were diagnosed as pregnant (85% v. 77%; P > 0.05) did not differ significantly between the goats exposed to well-fed or undernourished bucks. The interval between the introduction of bucks and the onset of estrous behavior was shorter in goats exposed to well-fed bucks compared to the interval for those goats exposed to undernourished bucks (2.5 ± 0.2 v. 9.5 ± 0.6 days; P < 0.05). We conclude that undernourishment reduces the testicular size and odor intensity responses in bucks exposed to long days, but that undernourished bucks are still able to stimulate reproductive activity in seasonally anestrous goats, as is also the case for well-fed bucks.
The circumstellar medium surrounding rotating massive stars as grb precursors
- B. Pérez-Rendón, J. Higuera, G. García-Segura, A. Santillán, L. Hernández-Cervantes
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- Journal:
- European Astronomical Society Publications Series / Volume 61 / 2013
- Published online by Cambridge University Press:
- 22 July 2013, pp. 371-373
- Print publication:
- 2013
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Long duration Gamma Ray Bursts (LGRB) are thought to originate from massive rotating stars and the interaction of their expanding jet will be affected by the structure of their circumburst medium. In this work we use rotating stellar models of massive stars to determine the state of circumbust material in various types of progenitor scenarios and we describe how this external matter can appear in GRB observations.
Interaction of HVCs with the Outskirts of Galactic Disks: Turbulence
- A. Santillán, F.J. Sánchez–Salcedo, J. Kim, J. Franco, L. Hernández–Cervantes
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- European Astronomical Society Publications Series / Volume 56 / 2012
- Published online by Cambridge University Press:
- 17 September 2012, pp. 343-346
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- 2012
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There exist many physical processes that may contribute to the driving of turbulence in galactic disks. Some of them could drive turbulence even in the absence of star formation. For example, hydrodynamic (HD) or magnetohydrodynamic (MHD) instabilities, frequent mergers of small satellite clumps, ram pressure, or infalling gas clouds. In this work we present numerical simulations to study the interaction of compact high velocity clouds (CHVC) with the outskirts of magnetized gaseous disks. With our numerical simulations we show that the rain of small HVCs onto the disk is a potential source of random motions in the outer parts of Hi disks.
The role of the random magnetic fields in the ISM: HVC numerical simulations
- Alfredo Santillán, J. Kim, F. J. Sánchez-Salcedo, J. Franco, L. Hernández-Cervantes
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- Journal:
- Proceedings of the International Astronomical Union / Volume 4 / Issue S259 / November 2008
- Published online by Cambridge University Press:
- 01 November 2008, pp. 91-92
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- November 2008
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We know that the galactic magnetic field possesses a random component in addition to the mean uniform component, with comparable strength of the two components. This random component is considered to play important roles in the evolution of the interstellar medium (ISM). In this work we present numerical simulations associated with the interaction of the supersonic flows located at high latitude in our Galaxy (High Velocity Clouds, HVC) with the magnetized galactic ISM in order to study the effect that produces a random magnetic field in the evolution of this objects.