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1.
Psychiatry Res ; 329: 115443, 2023 11.
Article in English | MEDLINE | ID: mdl-37769372

ABSTRACT

Natural disasters such as public health epidemics may potentially affect suicide rates. The global COVID-19 pandemic poses an unprecedented challenge for healthcare systems and general populations worldwide. In this retrospective ecological study, we aimed to examine any changes in the suicide rates during the COVID-19 pandemic and to assess the relationship between COVID-19 death rates and deaths by suicide in Brazil. Data on suicide and COVID-19 case numbers were extracted from the Ministry of Health agencies and grouped weekly. We performed a time series analysis of suicide rates, a comparison of mean suicide rates between the pre-COVID-19 period and the COVID-19 period, and conducted a Poisson regression to examine the relationship between deaths due to COVID-19 and suicide rates. Our results showed decreased suicide rates during the COVID-19 pandemic. We also found that deaths owing to COVID-19 impact those owing to suicide after 10 weeks in the upward direction; however, we did not observe for enough time to see a change in the suicide rate curve. These findings are fundamental to understand suicidal behaviors in epidemic situations. However, the field needs more studies evaluating the impact of significant public health events on suicidality, incorporating extended follow-up periods.


Subject(s)
COVID-19 , Suicide , Humans , Brazil/epidemiology , Pandemics , Retrospective Studies
2.
Mar Pollut Bull ; 174: 113296, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34995889

ABSTRACT

This study aimed to assess the influence of treated wastewater disposal on Ria Formosa coastal lagoon (South Portugal), the largest national producer of bivalve mollusks. Water quality was evaluated at two areas under different wastewater loads and hydrodynamic conditions, using physico-chemical variables, bacterial indicators of contamination, chlorophyll-a concentration, phytoplankton abundance and composition. Samples were collected monthly, between October 2018 and September 2019. Minor influence of effluent discharge was detected at the eastern Olhão area, exposed to stronger hydrodynamics and higher wastewater load than the northwestern Faro area (ca. 2-4-fold total nitrogen and phosphorus). The lower load weakly flushed area showed a poorer water quality, up to 500 m from the discharge point, more marked during the spring-summer period. The intensity, persistence, and spatial extent of the wastewater footprint, lower for the highest-loading area, reflected the role of local hydrodynamic conditions, modulating the influence of wastewater discharge on lagoonal water quality.


Subject(s)
Wastewater , Water Quality , Environmental Monitoring , Hydrodynamics , Portugal , Taiwan
3.
J Intellect Disabil Res ; 64(8): 629-643, 2020 08.
Article in English | MEDLINE | ID: mdl-32608096

ABSTRACT

BACKGROUND: Poor eye contact and joint attention are early signs of autism spectrum disorder (ASD) and important prerequisites for developing other socio-communicative skills. Teaching parents evidence-based techniques to improve these skills can impact the overall functioning of children with ASD. We aimed to analyse the impact of conducting a group parent-training intervention with video modelling to improve the intelligent quotient (IQ), social and communication functioning and to minimise symptoms in children with ASD and intellectual disability (ID). METHODS: Study design: A multicentre, single-blinded, randomised clinical pilot trial of parent training using video modelling was conducted. SAMPLE: Sixty-seven parents of children with ASD, aged between 3 and 6 years and with IQs between 50 and 70, were randomised: 34 to the intervention group and 33 to the control group. Intervention program: The intervention group received parent training over 22 sessions, and the control group received the standard community treatment. INSTRUMENTS: Pre-evaluation and post-evaluation (week 28), the following were used: Autism Diagnostic Interview, Vineland Adaptive Behaviour Scale I, Snijders-Oomen Nonverbal Intelligence Test, Autism Behaviour Checklist and Hamilton Depression Rating Scale. DATA ANALYSIS: Intention to treat and complier-average causal effect (CACE) were used to estimate the effects of the intervention. RESULTS: There was a statistically significant improvement in the Vineland standardized communication scores in CACE (Cohen's d = 0.260). There was a non-statistically significant decrease in autism symptomatology (Autism Behaviour Checklist total scores) and a significant increase in the non-verbal IQ in the intervention group. After the false discovery rate correction was applied, IQ remained statistically significant under both paradigms. The effect size for this adjusted outcome under the intention-to-treat paradigm was close to 0.4, and when considering adherence (CACE), the effect sizes were more robust (IQ's Cohen's d = 0.433). CONCLUSIONS: Parent training delivered by video modelling can be a useful technique for improving the care given to children with ASD and ID, particularly in countries that lack specialists.


Subject(s)
Autism Spectrum Disorder/therapy , Education, Nonprofessional , Intellectual Disability/therapy , Outcome Assessment, Health Care , Parents , Adult , Child , Child, Preschool , Education, Nonprofessional/methods , Female , Humans , Male , Pilot Projects , Single-Blind Method , Video Recording
4.
Comput Methods Biomech Biomed Engin ; 23(8): 408-421, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32189515

ABSTRACT

The present study aims to compare spinal stability after two different minimally invasive techniques, the lateral lumbar interbody fusion (LLIF) and the transforaminal lumbar interbody fusion (TLIF) approaches. Two nonlinear three-dimensional finite element (FE) models of the L4-L5 functional spinal unit (FSU) were subjected to the loads that usually act on the lumbar spine. Findings show that the LLIF approach yields better results for torsion load case, due to the larger surface area of the implant. For extension, flexion and lateral bending loads, the TLIF approach presents smaller displacements probably due to the anterior placement of the cage and to the smaller damaged area of the annulus fibrosus.


Subject(s)
Computer Simulation , Lumbar Vertebrae/surgery , Minimally Invasive Surgical Procedures , Numerical Analysis, Computer-Assisted , Spinal Fusion , Biomechanical Phenomena , Cancellous Bone/surgery , Cortical Bone/surgery , Humans , Models, Theoretical , Prostheses and Implants , Reproducibility of Results , Rotation , Stress, Mechanical
6.
Acta Psychiatr Scand ; 136(6): 623-636, 2017 12.
Article in English | MEDLINE | ID: mdl-29080396

ABSTRACT

OBJECTIVE: In adulthood, the diagnosis of attention-deficit/hyperactivity disorder (ADHD) has been subject of recent controversy. We searched for a neuroanatomical signature associated with ADHD spectrum symptoms in adults by applying, for the first time, machine learning-based pattern classification methods to structural MRI and diffusion tensor imaging (DTI) data obtained from stimulant-naïve adults with childhood-onset ADHD and healthy controls (HC). METHOD: Sixty-seven ADHD patients and 66 HC underwent high-resolution T1-weighted and DTI acquisitions. A support vector machine (SVM) classifier with a non-linear kernel was applied on multimodal image features extracted on regions of interest placed across the whole brain. RESULTS: The discrimination between a mixed-gender ADHD subgroup and individually matched HC (n = 58 each) yielded area-under-the-curve (AUC) and diagnostic accuracy (DA) values of up to 0.71% and 66% (P = 0.003) respectively. AUC and DA values increased to 0.74% and 74% (P = 0.0001) when analyses were restricted to males (52 ADHD vs. 44 HC). CONCLUSION: Although not at the level of clinically definitive DA, the neuroanatomical signature identified herein may provide additional, objective information that could influence treatment decisions in adults with ADHD spectrum symptoms.


Subject(s)
Attention Deficit Disorder with Hyperactivity/diagnosis , Attention Deficit Disorder with Hyperactivity/physiopathology , Brain/diagnostic imaging , Brain/physiopathology , Magnetic Resonance Imaging/methods , Support Vector Machine , Adult , Diffusion Tensor Imaging/methods , Female , Humans , Male , Neurobiology
7.
BMC Psychiatry ; 17(1): 277, 2017 07 28.
Article in English | MEDLINE | ID: mdl-28754160

ABSTRACT

BACKGROUND: Low- and middle-income countries (LMICs) face a lack of epidemiological data. The development of high-quality surveys is a key research priority in countries such as Brazil. Our aim is to discuss the difficulties in conducting a longitudinal epidemiological survey in a pilot study of a school-based sample in São Paulo. METHODS: Data came from a cohort of school-attending adolescents in two neighborhoods with different levels of urbanicity in São Paulo. Students born in 2002 and in the 7th grade during 2014 were recruited from nine public schools. Adolescents and caregivers were interviewed separately at baseline and at one year follow-up, using several instruments, including the Schedule for Affective Disorders and Schizophrenia for School-Age Children/Present and Lifetime Version (K-SADS-PL). RESULTS: Achieving unbiased sampling, keeping an updated register of participants' contact information, using a full clinical interview without an algorithm for its scoring, and maintaining a highly-trained research team were among the difficulties faced. CONCLUSION: Working closely with community leaders, organizing group efforts to perform interviews, using a short, easy to understand instrument and providing some reward for participants were identified as alternatives to dealing with these difficulties, useful not only in Brazil, but also in other LMICs.


Subject(s)
Data Collection/methods , Mood Disorders/epidemiology , Research Design , Schizophrenia/epidemiology , Students/statistics & numerical data , Adolescent , Bias , Brazil/epidemiology , Child , Female , Humans , Income , Longitudinal Studies , Male , Pilot Projects , Registries , Reproducibility of Results , Schools/statistics & numerical data , Students/psychology
8.
Curr Oncol ; 24(2): e146-e151, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28490938

ABSTRACT

INTRODUCTION: Survival after a diagnosis of brain metastasis in non-small-cell lung cancer (nsclc) is generally poor. We previously reported a median survival of approximately 4 months in a cohort of patients treated with whole-brain radiotherapy (wbrt). Since that time, we implemented a program of stereotactic radiosurgery (srs). In the present study, we examined survival and prognostic factors in a consecutive cohort of patients after the introduction of the srs program. METHODS: Data from a retrospective review of 167 nsclc patients with brain metastasis referred to a tertiary cancer centre during 2010-2012 were compared with data from a prior cohort of 91 patients treated during 2005-2007 ("pre-srs cohort"). RESULTS: Median overall survival from the date of diagnosis of brain metastasis (4.3 months in the srs cohort vs. 3.9 months in the pre-srs cohort, p = 0.74) was not significantly different in the cohorts. The result was similar when the no-treatment group was excluded from the srs cohort. Within the srs cohort only, significant differences is overall survival were observed between treatment groups (srs, wbrt plus srs, wbrt, and no treatment), with improved survival being observed on univariate and multivariate analysis for patients receiving srs compared with patients receiving wbrt alone (p < 0.001). CONCLUSIONS: No improvement in survival was observed for nsclc patients with brain metastases after the implementation of srs. Selected patients (younger age, female sex, good performance status, fewer brain metastases) treated with srs appeared to demonstrate improved survival. However, those observations might also reflect better patient selection for srs or a greater tendency to offer those patients systemic therapy in addition to srs.

9.
Br Poult Sci ; 55(6): 728-31, 2014.
Article in English | MEDLINE | ID: mdl-25269694

ABSTRACT

1. objective of the present study was to estimate heritability for hatch weight (HW), body weight at 90 (W90) and 180 (W180) d of age in Brazilian ostriches. 2. The heritability estimates were obtained through the restricted maximum likelihood method for an animal model. Least squares method was used to define possible fixed effects for consideration in the analysis model. 3. The estimates of heritability were 0.42 ± 0.05, 0.16 ± 0.04 and 0.24 ± 0.08 for HW, W90 and W180, respectively. 4. Heritability estimates showed that there are sufficient levels of additive genetic variation present in the traits studied, and these traits may respond to selection.


Subject(s)
Body Weight/genetics , Struthioniformes/anatomy & histology , Animals , Hybridization, Genetic , Male , Phenotype , Quantitative Trait, Heritable , Struthioniformes/genetics
10.
Mol Phylogenet Evol ; 70: 323-36, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24099890

ABSTRACT

The Ciminalis section of Gentiana comprises seven species, two of them growing on siliceous substrates (G. alpina and G. acaulis), the other ones being calcareous taxa (G. clusii, G. angustifolia, G. ligustica, G. occidentalis and G. dinarica). A total of 515 individuals from 183 populations over the entire Ciminalis distribution range was analyzed using four chloroplast loci (trnH-psbA, matK, rpoB and rpoC1) and the nuclear ribosomal marker ITS2. The siliceous species display only two chloroplast haplotypes each and are both characterized by patterns of range expansions all over the Alps. Conversely, the calcareous species are on average more diverse (two to 13 haplotypes per species) with strong patterns of local structuring. We suggest that the occurrence of many calcareous refugia at the periphery of the Alps must have led to local adaptation and morphological diversification, and helped preserving intraspecific diversities during the last glaciations for the associated taxa. ITS2 was more efficient in delineating species boundaries than the chloroplast markers for which several haplotypes are shared among species. This might be either due to chloroplast capture among species and/or to recent divergence. Species adapted to the same substrate are generally only distantly related when they co-occur in the same place. For both types of markers, G. clusii is found genetically distant from all other species.


Subject(s)
Gentiana/genetics , Phylogeny , Chloroplasts/genetics , Europe , Genetic Loci , Genetic Variation , Genotype , Gentiana/classification , Haplotypes , Humans , Phylogeography , Sequence Analysis, DNA
11.
Poult Sci ; 92(1): 277-82, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23243259

ABSTRACT

The objective of this study was to fit growth curves using nonlinear and linear functions to describe the growth of ostriches in a Brazilian population. The data set consisted of 112 animals with BW measurements from hatching to 383 d of age. Two nonlinear growth functions (Gompertz and logistic) and a third-order polynomial function were applied. The parameters for the models were estimated using the least-squares method and Gauss-Newton algorithm. The goodness-of-fit of the models was assessed using R(2) and the Akaike information criterion. The R(2) calculated for the logistic growth model was 0.945 for hens and 0.928 for cockerels and for the Gompertz growth model, 0.938 for hens and 0.924 for cockerels. The third-order polynomial fit gave R(2) of 0.938 for hens and 0.924 for cockerels. Among the Akaike information criterion calculations, the logistic growth model presented the lowest values in this study, both for hens and for cockerels. Nonlinear models are more appropriate for describing the sigmoid nature of ostrich growth.


Subject(s)
Struthioniformes/growth & development , Aging/physiology , Agriculture , Animals , Brazil , Models, Biological
12.
Animal ; 7(4): 540-6, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23034151

ABSTRACT

In most studies on beef cattle longevity, only the cows reaching a given number of calvings by a specific age are considered in the analyses. With the aim of evaluating all cows with productive life in herds, taking into consideration the different forms of management on each farm, it was proposed to measure cow longevity from age at last calving (ALC), that is, the most recent calving registered in the files. The objective was to characterize this trait in order to study the longevity of Nellore cattle, using the Kaplan-Meier estimators and the Cox model. The covariables and class effects considered in the models were age at first calving (AFC), year and season of birth of the cow and farm. The variable studied (ALC) was classified as presenting complete information (uncensored = 1) or incomplete information (censored = 0), using the criterion of the difference between the date of each cow's last calving and the date of the latest calving at each farm. If this difference was >36 months, the cow was considered to have failed. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The records of 11 791 animals from 22 farms within the Nellore Breed Genetic Improvement Program ('Nellore Brazil') were used. In the estimation process using the Kaplan-Meier model, the variable of AFC was classified into three age groups. In individual analyses, the log-rank test and the Wilcoxon test in the Kaplan-Meier model showed that all covariables and class effects had significant effects (P < 0.05) on ALC. In the analysis considering all covariables and class effects, using the Wald test in the Cox model, only the season of birth of the cow was not significant for ALC (P > 0.05). This analysis indicated that each month added to AFC diminished the risk of the cow's failure in the herd by 2%. Nonetheless, this does not imply that animals with younger AFC had less profitability. Cows with greater numbers of calvings were more precocious than those with fewer calvings.


Subject(s)
Cattle/physiology , Longevity , Parturition , Aging , Animals , Brazil , Female , Kaplan-Meier Estimate , Models, Biological , Pregnancy , Proportional Hazards Models
13.
Poult Sci ; 91(11): 2977-87, 2012 Nov.
Article in English | MEDLINE | ID: mdl-23091159

ABSTRACT

Egg production curves describe the laying patterns of hen populations over time. The objectives of this study were to fit the weekly egg production rate of selected and nonselected lines of a White Leghorn hen population, using nonlinear and segmented polynomial models, and to study how the selection process changed the egg-laying patterns between these 2 lines. Weekly egg production rates over 54 wk of egg production (from 17 to 70 wk of age) were measured from 1,693 and 282 laying hens from one selected and one nonselected (control) genetic line, respectively. Six nonlinear and one segmented polynomial models were gathered from the literature to investigate whether they could be used to fit curves for the weekly egg production rate. The goodness of fit of the models was measured using Akaike's information criterion, mean square error, coefficient of determination, graphical analysis of the fitted curves, and the deviations of the fitted curves. The Logistic, Yang, Segmented Polynomial, and Grossman models presented the best goodness of fit. In this population, there were significant differences between the parameter estimates of the curves fitted for the selected and nonselected lines, thus indicating that the effect of selection changed the shape of the egg production curves. The selection for egg production was efficient in modifying the birds' egg production curve in this population, thus resulting in genetic gain from the 5th to the 54th week of egg laying and improved the peak egg production and the persistence of egg laying.


Subject(s)
Chickens/genetics , Chickens/physiology , Oviposition/genetics , Oviposition/physiology , Selection, Genetic/physiology , Animals , Female , Models, Biological
14.
Mol Ecol ; 21(11): 2743-60, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22509817

ABSTRACT

This study puts together genetic data and an approximate bayesian computation (ABC) approach to infer the time at which the tree Geoffroea spinosa colonized the Galápagos Islands. The genetic diversity and differentiation between Peru and Galápagos population samples, estimated using three chloroplast spacers and six microsatellite loci, reveal significant differences between two mainland regions separated by the Andes mountains (Inter Andean vs. Pacific Coast) as well as a significant genetic differentiation of island populations. Microsatellites identify two distinct geographical clusters, the Galápagos and the mainland, and chloroplast markers show a private haplotype in the Galápagos. The nuclear distinctiveness of the Inter Andean populations suggests current restricted pollen flow, but chloroplast points to cross-Andean dispersals via seeds, indicating that the Andes might not be an effective biogeographical barrier. The ABC analyses clearly point to the colonization of the Galápagos within the last 160,000 years and possibly as recently as 4750 years ago (475 generations). Founder events associated with colonization of the two islands where the species occurs are detected, with Española having been colonized after Floreana. We discuss two nonmutually exclusive possibilities for the colonization of the Galápagos, recent natural dispersal vs. human introduction.


Subject(s)
Fabaceae/genetics , Genetic Variation , Bayes Theorem , Chloroplasts/genetics , Ecuador , Founder Effect , Haplotypes , Introduced Species , Microsatellite Repeats , Models, Genetic , Molecular Sequence Data , Peru , Phylogeography , Time Factors
15.
Meat Sci ; 91(3): 352-7, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22405874

ABSTRACT

In this study, the objective was to estimate genetic parameters of body weight at 210 (BW210) and 365 (BW365) days of age in relation to rib eye area (REA), subcutaneous back fat thickness (BF) and rump fat (RF), and their respective genetic trends, in Nelore beef cattle. Estimates of genetic parameters and breeding values for the studied traits were obtained using the REML method. The direct and maternal heritability estimates were respectively: 0.25±0.02 and 0.21±0.01, for BW210, and 0.29±0.02 and 0.09±0.01, for BW365. The heritability estimates for transformed REA, BF and RF were 0.29±0.03, 0.21±0.02 and 0.23±0.03, respectively. There were genetic associations between BW210 and REA, BW365 and REA, and BF and RF, while the other correlations were low. The selection process that was conducted at the farms participating in the breeding program, taking the proposed selection index into consideration, caused genetic changes to these traits.


Subject(s)
Adipose Tissue/metabolism , Body Weight/genetics , Breeding/methods , Cattle/genetics , Dietary Fats/analysis , Meat/analysis , Quantitative Trait, Heritable , Animals , Cattle/growth & development
16.
Poult Sci ; 90(10): 2174-88, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21933998

ABSTRACT

The objectives of this paper were to identify the phenotypic egg-laying patterns in a White Leghorn line mainly selected for egg production, to estimate genetic parameters of traits related to egg production and to evaluate the genetic association between these by principal components analysis to identify trait(s) that could be used as selection criteria to improve egg production. Records of 54 wk of egg production from a White Leghorn population were used. The data set contained records of the length:width ratio of eggs at 32, 37, and 40 wk of age; egg weight at 32, 37, and 40 wk of age; BW at 54 and 62 wk of age; age at first egg; early partial egg production rate from 17 to 30 wk and from 17 to 40 wk of age; late partial egg production rate from 30 to 70 wk and from 40 to 70 wk of age; and total egg production rate (TEP). The estimates of genetic parameters between these traits were estimated by the restricted maximum likelihood method. Multivariate analyses were performed: a hierarchical cluster analysis, a nonhierarchical clustering analysis by the k-means method of weekly egg production rate to describe the egg-laying patterns of hens, and a principal components analysis using the breeding values of all traits. The highest heritability estimates were obtained for BW at 54 wk of age (0.68 ± 0.07) and age at first egg (0.53 ± 0.07). It is recommended that a preliminary clustering analysis be performed to obtain the population structure that takes into account the pattern of egg production, rather than the TEP, because hens may have the same final egg production with different patterns of egg laying. Early partial production periods were not good indicators for use in improving total egg production because these traits presented an overestimated genetic correlation with TEP because of the part-whole genetic correlation component. Egg production might be improved by selecting individuals based on TEP.


Subject(s)
Breeding , Chickens/genetics , Chickens/physiology , Eggs , Oviposition/genetics , Quantitative Trait, Heritable , Animals , Cluster Analysis , Female , Phenotype , Principal Component Analysis , Selection, Genetic
17.
Psychother Psychosom ; 80(3): 144-50, 2011.
Article in English | MEDLINE | ID: mdl-21372622

ABSTRACT

BACKGROUND: This study evaluated the effectiveness of adjunctive cognitive behavioral group therapy (CBGT) to prevent recurrence of episodes in euthymic patients with bipolar disorder. METHODS: A randomized controlled single-blind trial was conducted with 50 patients with bipolar disorder types I and II followed up for at least 12 months in an outpatient service and whose disease was in remission. An experimental CBGT manual was developed and added to treatment as usual (TAU), and results were compared with TAU alone. RESULTS: Intention-to-treat analysis showed that there was no difference between groups in terms of time until any relapse (Wilcoxon = 0.667; p = 0.414). When considering type of relapse, there was still no difference in either depressive (Wilcoxon = 3.328; p = 0.068) or manic episodes (Wilcoxon = 1.498; p = 0.221). Although occurrence of episodes also did not differ between groups (χ(2) = 0.28; p = 0.59), median time to relapse was longer for patients treated with CBGT compared to TAU (Mann-Whitney = -2.554; p = 0.011). CONCLUSIONS: Time to recurrence and number of episodes were not different in the group of patients treated with CBGT. However, median time to relapse was shorter in the TAU group. Studies with larger samples may help to clarify whether our CBGT approach prevents new episodes of bipolar disorder. Our findings also indicated that CBGT is feasible in euthymic patients with bipolar disorder and should be investigated in future studies. To our knowledge, this is the first publication of a controlled trial of CBGT for euthymic patients with bipolar disorder.


Subject(s)
Bipolar Disorder/therapy , Cognitive Behavioral Therapy/methods , Adolescent , Adult , Brazil , Female , Follow-Up Studies , Humans , Male , Middle Aged , Recurrence , Single-Blind Method , Statistics, Nonparametric , Treatment Outcome , Young Adult
18.
Poult Sci ; 90(3): 705-11, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21325246

ABSTRACT

Neural networks are capable of modeling any complex function and can be used in the poultry and animal production areas. The aim of this study was to investigate the possibility of using neural networks on an egg production data set and fitting models to the egg production curve by applying 2 approaches, one using a nonlinear logistic model and the other using 2 artificial neural network models [multilayer perceptron (MLP) and radial basis function]. Two data sets from 2 generations of a White Leghorn strain that had been selected mainly for egg production were used. In the first data set, the mean weekly egg-laying rate was ascertained over a 54-wk egg production period. This data set was used to adjust and test the logistic model and to train and test the neural networks. The second data set, covering 52 wk of egg production, was used to validate the models. The mean absolute deviation, mean square error, and R(2) were used to evaluate the fit of the models. The MLP neural network had the best fit in the test and validation phases. The advantage of using neural networks is that they can be fitted to any kind of data set and do not require model assumptions such as those required in the nonlinear methodology. The results confirm that MLP neural networks can be used as an alternative tool to fit to egg production. The benefits of the MLP are the great flexibility and their lack of a priori assumptions when estimating a noisy nonlinear model.


Subject(s)
Chickens/physiology , Models, Biological , Oviposition/physiology , Animals , Female , Logistic Models , Neural Networks, Computer , Time Factors
19.
Mol Ecol ; 17(13): 3147-59, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18522691

ABSTRACT

Today, the Seasonally Dry Tropical Forests (SDTF) of eastern South America occur as large, well-defined nuclei (e.g. Caatinga in the northeast) and as smaller enclaves within other vegetations (e.g. Cerrado and Chaco). In order to infer the way the present SDTF distribution was attained, the genetic structure of Astronium urundeuva, a tree confined to SDTF, was assessed using two chloroplast spacers and nine microsatellite loci. Five haplotypes were identified, whose distribution was spatially structured. The distribution of the two most common and divergent haplotypes suggested former vicariance and progressive divergence due to isolation. More recent range expansions of these two lineages subsequently occurred, leading to a secondary contact at the southern limit of the Caatinga SDTF nucleus. The multilocus-Bayesian approach using microsatellites consistently identified three groups of populations (Northeast, Central and Southwest). Isolation by distance was found in Northeast and Southwest groups whereas admixture was detected in the Central group, located at the transition between Caatinga and Cerrado domains. All together, the results support the existence of range expansions and secondary contact in the Central group. This study provides arguments that favour the existence of a previously more continuous formation of SDTF in eastern South America.


Subject(s)
Anacardiaceae/genetics , Trees/genetics , Tropical Climate , Anacardiaceae/classification , Anacardiaceae/growth & development , Cluster Analysis , DNA, Chloroplast/chemistry , DNA, Chloroplast/genetics , Ecosystem , Genetic Variation , Genetics, Population , Geography , Microsatellite Repeats/genetics , Molecular Sequence Data , Phylogeny , Seasons , Sequence Analysis, DNA , South America , Trees/classification , Trees/growth & development
20.
Mol Phylogenet Evol ; 39(3): 734-46, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16515866

ABSTRACT

This study extends the geographic coverage of a previous study of mitochondrial DNA restriction fragment length polymorphism in European anchovy. Both studies together include 24 samples representing 17 localities extending from the Black Sea, through the Mediterranean Sea to the eastern Atlantic as far south as Dakar, Senegal. Eighty-eight haplotypes define two clades (A and B) separated by 3.2% sequence divergence. Clade A has a star-like genealogy indicative of a recent population expansion. Clade B has a more complex genealogy, consisting of several haplotypes at intermediate frequencies. The distributions of these clades consist of a mosaic with abrupt changes between some areas and gradients between other areas. Clade A predominates the Black and Aegean seas, but is present throughout the Mediterranean. Unexpectedly, new data show that clade A is also at a high frequency in the Atlantic, from Portugal to at least Senegal. Overall, the level of genetic differentiation among populations is high (F(ST)=0.148, p<0.0001), with the greatest differences between basins. AMOVA reveals four main geographical groups: Atlantic, central Mediterranean, Aegean Sea, and Black Sea. Mismatch distribution clearly indicates historical bottleneck and population expansion for clade A, while for clade B such evidence is equivocal. This difference may reflect a range expansion for both clades, but with higher gene flow (Nm values) between demes for clade A. Both contemporary and historical processes are important in shaping the complex genetic population structure of European anchovy.


Subject(s)
DNA, Mitochondrial/genetics , Fishes/classification , Fishes/genetics , Mosaicism , Phylogeny , Animals , Geography , Haplotypes , Polymorphism, Restriction Fragment Length
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