Browsing by Author "Gonçalves, David"
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- A method for sex estimation using the proximal femurPublication . Curate, Francisco; Coelho, João; Gonçalves, David; Coelho, Catarina; Ferreira, Maria Teresa; Navega, David; Cunha, EugéniaThe assessment of sex is crucial to the establishment of a biological profile of an unidentified skeletal individual. The best methods currently available for the sexual diagnosis of human skeletal remains generally rely on the presence of well-preserved pelvic bones, which is not always the case. Postcranial elements, including the femur, have been used to accurately estimate sex in skeletal remains from forensic and bioarcheological settings. In this study, we present an approach to estimate sex using two measurements (femoral neck width [FNW] and femoral neck axis length [FNAL]) of the proximal femur. FNW and FNAL were obtained in a training sample (114 females and 138 males) from the Luis Lopes Collection (National History Museum of Lisbon). Logistic regression and the C4.5 algorithm were used to develop models to predict sex in unknown individuals. Proposed cross-validated models correctly predicted sex in 82.5-85.7% of the cases. The models were also evaluated in a test sample (96 females and 96 males) from the Coimbra Identified Skeletal Collection (University of Coimbra), resulting in a sex allocation accuracy of 80.1-86.2%. This study supports the relative value of the proximal femur to estimate sex in skeletal remains, especially when other exceedingly dimorphic skeletal elements are not accessible for analysis. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
- Multi-isotope approaches to the Neolithic cemetery-cave of Bom Santo (Lisbon): new data and comparisons with fourth millennium BC populations from central-southern PortugalPublication . Carvalho, AF; Gonçalves, David; Bonilla, Marta Diaz-Zorita; João Valente, MariaPrevious multi-isotopic research on the human remains of the Neolithic cave-cemetery of Bom Santo (Lisbon, Portuguese Estremadura) led to the conclusion that this fourth millennium BC population was very heterogeneous at several levels. Two in particular were subsistence habits and mobility: although consumption of terrestrial foods was the norm, aquatic food sources totalling > 20% of overall diets were detected in 60% of the population, and, surprisingly, 79% of the individuals were classed as non-local, having lived most of their life in geologically older regions. These figures were however obtained on a sample of 15 individuals. Further isotopic analyses have enlarged the original sample to 35 individuals (i.e., half of the exhumed population) and were also employed in the study of the coeval cave-cemeteries of Barrao and Mureta. This has permitted a sounder depiction of past behaviours, with a structural difference being observed at both levels between Bom Santo and the latter sites: at the former cave, 70% of the population consumed > 20% of aquatic foods and 34% were non-local (23% from outside Estremadura), whereas the latter were all local and showed no signals of aquatic diets. Comparison with other fourth millennium BC populations in central-southern Portugal suggests a model where the exploitation of locally available aquatic/marine food sources was not mandatory but optional and that human mobility represented an important socio-economic behavioural feature of these (presumably) segmentary societies. How both aspects related to the then-emerging megalithic phenomenon is a question that should be investigated in future research.
- Oestradiol and prostaglandin F2 alpha regulate sexual displays in females of a sex-role reversed fishPublication . Gonçalves, David; Costa, Silvia Santos; Teles, Magda C.; Silva, Helena; Inglês, Mafalda; Oliveira, Rui F.The mechanisms regulating sexual behaviours in female vertebrates are still poorly understood, mainly because in most species sexual displays in females are more subtle and less frequent than displays in males. In a sex-role reversed population of a teleost fish, the peacock blenny Salaria pavo, an external fertilizer, females are the courting sex and their sexual displays are conspicuous and unambiguous. We took advantage of this to investigate the role of ovarian-synthesized hormones in the induction of sexual displays in females. In particular, the effects of the sex steroids oestradiol (E2) and testosterone (T) and of the prostaglandin F2 alpha (PGF2 alpha) were tested. Females were ovariectomized and their sexual behaviour tested 7 days (sex steroids and PGF2 alpha) and 14 days (sex steroids) after ovariectomy by presenting females to an established nesting male. Ovariectomy reduced the expression of sexual behaviours, although a significant proportion of females still courted the male 14 days after the ovary removal. Administration of PGF2 alpha to ovariectomized females recovered the frequency of approaches to the male's nest and of courtship displays towards the nesting male. However, E2 also had a positive effect on sexual behaviour, particularly on the frequency of approaches to the male's nest. T administration failed to recover sexual behaviours in ovariectomized females. These results suggest that the increase in E2 levels postulated to occur during the breeding season facilitates female mate-searching and assessment behaviours, whereas PGF2 alpha acts as a short-latency endogenous signal informing the brain that oocytes are mature and ready to be spawned. In the light of these results, the classical view for female fishes, that sex steroids maintain sexual behaviour in internal fertilizers and that prostaglandins activate spawning behaviours in external fertilizers, needs to be reviewed.
- One for all and all for one: Linear regression from the mass of individual bones to assess human skeletal mass completenessPublication . Gonçalves, David; Coelho, João d'Oliveira; Acosta, Maria A.; Coelho, Catarina; Curate, Francisco; Ferreira, Maria Teresa; Gouveia, Márcia; Makhoul, Calil; Pinto, Débora; Oliveira-Santos, Inês; Vassalo, Ana R.; Navega, David; Cunha, EugéniaObjectivesComplete and accurate human skeletal inventory is seldom possible in archaeological and forensic cases involving severe fragmentation. In such cases, skeletal mass comparisons with published references may be used as an alternative to assess skeletal completeness but they are too general for a case-by-case routine analysis. The objective is to solve this issue by creating linear regression equations to estimate the total mass of a skeleton based on the mass of individual bones.Materials and MethodsTotal adult skeletal mass and individual mass of the clavicle, humerus, femur, patella, carpal, metacarpal, tarsal, and metatarsal bones were recorded in a sample of 60 skeletons from the 21st century identified skeletal collection (University of Coimbra). The sample included 32 females and 28 males with ages ranging from 31 to 96 years (mean=76.4; sd=14.8). Skeletal mass linear regression equations were calculated based on this sample.ResultsThe mass of individual bones was successfully used to predict the approximate total mass of the adult skeleton. The femur, humerus, and second metacarpal were the best predictors of total skeletal mass with root mean squared errors ranging from 292.9 to 346.1 g.DiscussionLinear regression was relatively successful at estimating adult skeletal mass. The non-normal distribution of the sample in terms of mass may have reduced the predictive power of the equations. These results have clear impact for bioanthropology, especially forensic anthropology, since this method may provide better estimates of the completeness of the skeleton or the minimum number of individuals. Am J Phys Anthropol 160:427-432, 2016. (c) 2016 Wiley Periodicals, Inc.
- Social cues in the expression of sequential alternative reproductive tactics in young males of the peacock blenny, Solaria pavoPublication . Fagundes, Teresa; Simões, Mariana G.; Gonçalves, David; Oliveira, Rui F.Phenotypic change in response to variation in environmental cues has been widely documented in fish. Transitions in social dominance, in particular, have been shown to induce a rapid switch in reproductive phenotypes in many species. However, this effect has been mainly studied in adults and focused on behavioural transitions. The way social cues constraint the phenotypic development of juveniles remains poorly studied in fish. We tested the importance of social dominance and density in the phenotypic development of juveniles of the peacock blenny Solaria pavo. This species shows sequential male alternative reproductive tactics. In the first breeding season males can reproduce as nest-holders or as parasitic males (female-mimicking), or postpone reproduction; from the following season afterwards all males reproduce as nest-holders. Parasitic males have relatively larger testes that lack a testicular gland, present in the testes of nest-holders. The testicular gland is the main source of androgens in the testes and accordingly nest-holders have higher circulating androgen levels. In addition, exogenous androgen administration to parasitic males promotes the development of secondary sexual characters (SSC) only present in nest-holders such as a head crest and an anal gland. We raised juveniles under a high or low-density treatment and monitored social interactions for 1 month. No significant effect of density on the development of juvenile males was detected. However, within each replicate, the relative body size of juvenile males at the beginning of the experiment determined their dominance status, with dominant males developing towards the nest-holder morphotype. Dominant males engaged in more nest defence behaviour, showed larger testicular glands, had higher levels of 11-ketotestosterone (11-KT) and testosterone (T) and developed more SSC, as compared to subordinate males. However, these effects of social dominance were moderated by body condition as only dominant males in good body condition developed SSC. The effect of social dominance and of the area of the testicular gland on the development of SSC was mediated by 11-KT and on the expression of nest defence behaviour by T. Interestingly, in spite of the higher androgen levels and more pronounced morphologic development of SSC in dominant individuals, gonadal development was independent of social dominance and most fish still had underdeveloped testis at the end of the experiment. In conclusion, social dominance promoted the development of the testicular gland, an increase in circulating androgen levels and the development of SSC, but did not promote testicular development. This suggests a dissociation of mechanisms underlying sexual maturation and the expression of male reproductive traits. This dissociation seems to be the key for the occurrence of female-mimicking males in this species, which are sexually mature despite lacking the SSC typical of nest-holdets. (C) 2012 Elsevier Inc. All rights reserved.
- The Bom Santo Cave (Lisbon, Portugal): catchment, diet, and patterns of mobility of a Middle Neolithic populationPublication . Carvalho, António Faustino; Alves-Cardoso, Francisca; Gonçalves, David; Granja, Raquel; Cardoso, João Luís; Dean, Rebecca M.; Francisco Gibaja, Juan; Masucci, Maria A.; Arroyo-Pardo, Eduardo; Fernández-Domínguez, Eva; Petchey, Fiona; Price, T. Douglas; Mateus, José Eduardo; Queiroz, Paula Fernanda; Callapez, Pedro; Pimenta, Carlos; Regala, Frederico T.The study of the Bom Santo Cave (central Portugal), a Neolithic cemetery, indicates a complex social, palaeoeconomic, and population scenario. With isotope, aDNA, and provenance, analyses of raw materials coupled with stylistic variability of material culture items and palaeogeographical data, light is shed on the territory and social organization of a population dated to 3800-3400 cal BC, i.e. the Middle Neolithic. Results indicate an itinerant farming, segmentary society, where exogamic practices were the norm. Its lifeway may be that of the earliest megalithic builders of the region, but further research is needed to correctly evaluate the degree of this community's participation in such a phenomenon.