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1.
Support Care Cancer ; 24(3): 1397-403, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26342484

RESUMEN

PURPOSE: We aimed to compare the complication rate between port catheters (PC) and peripherally inserted central catheters (PICC) for the administration of postoperative chemotherapy for breast cancer. METHODS: All patients treated from January 2010 to August 2012 at the Centre Henri Becquerel for early breast cancer requiring postoperative chemotherapy were retrospectively screened. The primary endpoint was the occurrence of a major complication related to the central venous catheter. Major complications were defined as any grade 3 event according to CTCAE 4.0, delay in chemotherapy >7 days, change of the device, life-threatening event, event requiring a hospitalization, or a prolongation of hospitalization. RESULTS: A total of 448 patients were included; 290 had a PC and 158 a PICC. Overall, 31 major complications related to the central venous catheter were observed: 13 for patients with a PC (4.5%) and 18 for patients with a PICC (11.4%). In univariate analysis, having a PICC was the only factor significantly associated with a higher risk of major complications (HR = 2.83, p = 0.0027). We observed a trend for a higher risk of major complications for patients older than 60 years or with BMI >25 (p = 0.06). In multivariate analysis, having a PICC was the only predictive factor of major complications (HR = 2.89, p = 0.004). CONCLUSIONS: In univariate and multivariate analysis, having a PICC instead of a PC was the only predictive factor of device-related major complication. If confirmed prospectively by the NCT02095743 ongoing trial, this result might modify the management of adjuvant chemotherapy administration.


Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Cateterismo Venoso Central/efectos adversos , Cateterismo Periférico/efectos adversos , Cateterismo Venoso Central/instrumentación , Cateterismo Venoso Central/métodos , Cateterismo Periférico/instrumentación , Cateterismo Periférico/métodos , Femenino , Humanos , Persona de Mediana Edad , Cuidados Posoperatorios , Estudios Retrospectivos
2.
Encephale ; 42(4): 333-9, 2016 Aug.
Artículo en Francés | MEDLINE | ID: mdl-26475395

RESUMEN

BACKGROUND: Body dissatisfaction among pregnant women can provoke behaviors to control weight gain and make them more vulnerable to eating disorders. Body dissatisfaction and strategies to control weight during pregnancy can have many consequences for both the mother and baby. Excessive weight gain may cause complications during childbirth and, reciprocally, a too weak weight gain could be associated with the risk of having a baby with a very low birth weight. Thus, it appears important to have a tool to detect these body image disorders in this population. As far as we know, no French-speaking tool exists, and the objective of this study was to investigate the psychometric properties of the French translation of the Pregnancy and Weight Gain Attitude Scale (PWGAS), which assesses the attitudes about weight gain during pregnancy. METHOD: The sample consisted of 553 women (29.32±4.82 years) in their third trimester of pregnancy. Participants were volunteer women recruited in hospitals during obstetric consultation. All participants completed an anamnestic questionnaire, the PWGAS and a questionnaire assessing body dissatisfaction (Body Shape Questionnaire [BSQ]). The PWGAS, in its original version, includes 18 items and consists of four subscales: Positive Pregnancy Body Image; Negative Pregnancy Body Image; Indifference toward Weight Gain and Weight Gain Restrictive Behaviors. The instrument was translated and verified by expert translators. RESULTS: Confirmatory factor analysis of the original version showed fit indices below recommended limits. An exploratory factor analysis on the PWGAS revealed the existence of five factors: "Fear about weight gain" (4 items); "Absence of weight gain preoccupation" (2 items); "Positive attitudes about weight gain" (4 items); "Feeling overwhelmed by weight gain" (3 items); and "Control over weight gain" (3 items). The goodness-of-fit of the five-factor model was satisfactory. The PWGAS (total and factors) is negatively correlated with the BSQ demonstrating its concurrent validity. CONCLUSION: The PWGAS has satisfactory psychometric properties. This questionnaire could certainly be integrated in the monitoring of pregnant women in order to detect and guide those who show negative attitudes about the weight gain so that they can benefit from adequate care and prevent the development of eating disorders.


Asunto(s)
Actitud , Imagen Corporal/psicología , Pruebas Neuropsicológicas , Embarazo/psicología , Psicometría , Aumento de Peso , Adulto , Femenino , Francia , Humanos , Lenguaje , Tercer Trimestre del Embarazo/psicología , Reproducibilidad de los Resultados , Encuestas y Cuestionarios , Traducciones
3.
Anim Cogn ; 18(2): 485-96, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25381576

RESUMEN

The generation and maintenance of within-population variation in cognitive abilities remain poorly understood. Recent theories propose that this variation might reflect the existence of consistent cognitive strategies distributed along a slow-fast continuum influenced by shyness. The slow-fast continuum might be reflected in the well-known speed-accuracy trade-off, where animals cannot simultaneously maximise the speed and the accuracy with which they perform a task. We test this idea on 49 wild-caught Carib grackles (Quiscalus lugubris), a tame opportunistic generalist Icterid bird in Barbados. Grackles that are fast at solving novel problems involving obstacle removal to reach visible food perform consistently over two different tasks, spend more time per trial attending to both tasks, and are those that show more shyness in a pretest. However, they are also the individuals that make more errors in a colour discrimination task requiring no new motor act. Our data reconcile some of the mixed positive and negative correlations reported in the comparative literature on cognitive tasks, suggesting that a speed-accuracy trade-off could lead to negative correlations between tasks favouring speed and tasks favouring accuracy, but still reveal consistent strategies based on stable individual differences.


Asunto(s)
Conducta Animal/fisiología , Individualidad , Passeriformes/fisiología , Solución de Problemas , Animales , Barbados , Color , Aprendizaje Discriminativo , Femenino , Aprendizaje , Masculino , Timidez , Factores de Tiempo
4.
Clin Genet ; 84(4): 326-34, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23495910

RESUMEN

Beckwith-Wiedemann syndrome (BWS) and Silver-Russell syndrome (SRS) are two congenital disorders with opposite outcomes on fetal growth, overgrowth and growth restriction, respectively. Although both disorders are heterogeneous, most cases of BWS and SRS are associated with opposite epigenetic or genetic abnormalities on 11p15.5 leading to opposite imbalances in the expression levels of imprinted genes. In this article, we review evidence implicating these genes in the developmental regulation of embryonic growth and placental function in mouse models. The emerging picture suggests that both SRS and BWS can be caused by the simultaneous and opposite deregulation of two groups of imprinted genes on 11p15.5. A detailed description of the phenotypic abnormalities associated with each syndrome must take into consideration the developmental functions of each gene involved.


Asunto(s)
Síndrome de Beckwith-Wiedemann/genética , Impresión Genómica , Síndrome de Silver-Russell/genética , Animales , Cromosomas Humanos Par 11 , Desarrollo Embrionario/genética , Femenino , Humanos , Fenotipo , Placenta/metabolismo , Embarazo
5.
Anim Cogn ; 16(3): 525-9, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23408337

RESUMEN

Behavioural innovations have been largely documented in birds and are thought to provide advantages in changing environments. However, the mechanisms by which behavioural innovations spread remain poorly known. Two major mechanisms are supposed to play a fundamental role: innovation diffusion by social learning and independent appearance of the same innovation in different individuals. Direct evidence for the independent emergence of the same innovation in different individuals is, however, lacking. Here, we show that a highly localized behavioural innovation previously observed in 2000 in Barbados, the opening of sugar packets by Loxigilla barbadensis bullfinches, persisted more than a decade later and had spread to a limited area around the initial site. More importantly, we found that the same innovation appeared independently in other, more distant, locations on the same island. On the island of St-Lucia, 145 km from Barbados, we also found that the sister species of the Barbados bullfinch, the Lesser Antillean bullfinch Loxigilla noctis developed the same innovation independently. Finally, we found that a third species, the Bananaquit Coereba flaveola, exploited the bullfinches' technical innovation to benefit from this new food source. Overall, our observations provide the first direct evidence of the independent emergence of the same behavioural innovation in different individuals of the same species, but also in different species subjected to similar anthropogenic food availability.


Asunto(s)
Conducta Alimentaria/psicología , Passeriformes , Animales , Barbados , Conducta Imitativa , Masculino
6.
Nat Genet ; 27(3): 257-8, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11242104

RESUMEN

Embryonic stem cells offer unprecedented opportunities for random or targeted genome alterations in the mouse. We present here an efficient strategy to create chromosome-specific loss of heterozygosity in embryonic stem cells. The combination of this method with genome-wide mutagenesis in ES cells (using chemical mutagens or gene-trap vectors) opens up the possibility for in vitro or in vivo functional screening of recessive mutations in the mouse.


Asunto(s)
Pérdida de Heterocigocidad , Células Madre/metabolismo , Animales , Femenino , Marcación de Gen , Técnicas Genéticas , Homocigoto , Kanamicina Quinasa/genética , Masculino , Ratones , Ratones Transgénicos , Mutagénesis
7.
Nat Genet ; 20(2): 163-9, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9771709

RESUMEN

Mest (also known as Peg1), an imprinted gene expressed only from the paternal allele during development, was disrupted by gene targeting in embryonic stem (ES) cells. The targeted mutation is imprinted and reversibly silenced by passage through the female germ line. Paternal transmission activates the targeted allele and causes embryonic growth retardation associated with reduced postnatal survival rates in mutant progeny. More significantly, Mest-deficient females show abnormal maternal behaviour and impaired placentophagia, a distinctive mammalian behaviour. Our results provide evidence for the involvement of an imprinted gene in the control of adult behaviour.


Asunto(s)
Retardo del Crecimiento Fetal/genética , Impresión Genómica , Conducta Materna , Proteínas/genética , Adulto , Alelos , Animales , Femenino , Marcación de Gen , Humanos , Masculino , Ratones , Datos de Secuencia Molecular , Linaje , Fenotipo , ARN Mensajero/metabolismo
8.
Arch Gerontol Geriatr ; 102: 104715, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35569288

RESUMEN

Embodied approach postulates that knowledge and conceptual representations are grounded in action and perception. In order to investigate the involvement of sensorimotor information in conceptual and cognitive processing, researchers have collected various norms in young adults. For instance, the perceptual strength (PS) assesses perceptual experience (i.e. visual, auditory, haptic, gustatory, olfactory) associated with a concept and the body-object-interaction (BOI) assesses the ease with which a human body can interact with the referent of a word. The importance of both BOI and PS in the multimodal composition of word meaning is today well recognized. However, given the sensorimotor development of the individual from childhood to later life, it is likely that different age periods are associated with different perceptual experience and capacity to interact with objects. The purpose of this research is to investigate exploratory the effect of age on PS and BOI by comparing the evaluation of 270 French language words by young adults and healthy older people. The results showed that older adults presented similar or even higher PS for some modalities (e.g. gustatory and olfactory) and in particular for certain categories of words, while the BOI decreases. In addition to the importance of adjusting the verbal stimuli used in aging studies when dealing with multimodal representations, our results will lead us to discuss the evolution of sensorimotor representations with age.


Asunto(s)
Envejecimiento , Lenguaje , Anciano , Niño , Humanos
9.
J Mater Sci Mater Med ; 22(5): 1321-32, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21512898

RESUMEN

The utility of porous metals for the integration of orthopaedic implants with host bone has been well established. Quantification of the tissue response to cementless implants is laborious and time consuming process requiring tissue processing, embedding, sectioning, polishing, imaging and image analysis. Micro-computed tomography (µCT) is a promising three dimensional (3D) imaging technique to quantify the tissue response to porous metals. However, the suitability and effectiveness of µCT for the quantification of bone ingrowth remains unknown. The purpose of this study was to evaluate and compare bone growth within porous titanium implants using both µCT and traditional hard-tissue histology techniques. Cylindrical implants were implanted in the distal femora and proximal tibiae of a rabbit. After 6 weeks, bone ingrowth was quantified and compared by µCT, light microscopy and backscattered electron microscopy. Quantification of bone volume and implant porosity as determined by µCT compared well with data obtained by traditional histology techniques. Analysis of the 3D dataset showed that bone was present in the pores connected with openings larger 9.4 µm. For pore openings greater than 28.2 µm, the size of the interconnection had little impact on the bone density within the porosity for the titanium foams.


Asunto(s)
Huesos/fisiología , Prótesis e Implantes , Titanio/química , Microtomografía por Rayos X , Animales , Masculino , Microscopía Electrónica de Rastreo , Conejos , Propiedades de Superficie
10.
J Mater Sci Mater Med ; 20(11): 2223-33, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19554427

RESUMEN

It is well known that interstitials affect the mechanical properties of titanium and titanium alloys. Their effects on the fatigue properties of titanium foams have not, however, been documented in the literature. This paper presents the effect of the oxygen content on the static and dynamic compression properties of titanium foams. Increasing the oxygen content from 0.24 to 0.51 wt% O in solution significantly increases the yield strength and reduces the ductility of the foams. However, the fatigue limit is not significantly affected by the oxygen content and falls within the 92 MPa +/- 12 MPa range for all specimens investigated in this study. During cyclic loading, deformation is initially coming from cumulative creep followed by the formation of microcracks. The coalescence of these microcracks is responsible for the rupture of the specimens. Fracture surfaces of the specimens having lower oxygen content show a more ductile aspect than the specimens having higher oxygen content.


Asunto(s)
Oxígeno/química , Titanio/química , Aleaciones/química , Fuerza Compresiva , Ensayo de Materiales , Metales/química , Microscopía Electrónica de Rastreo/métodos , Equipo Ortopédico , Porosidad , Polvos , Presión , Soluciones , Propiedades de Superficie , Temperatura , Resistencia a la Tracción
11.
Mol Cell Biol ; 13(9): 5393-407, 1993 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8395004

RESUMEN

The Saccharomyces cerevisiae SPT2 gene was identified by genetic screens for mutations which are suppressors of Ty and delta insertional mutations at the HIS4 locus. The ability of spt2 mutations to suppress the transcriptional interference caused by the delta promoter insertion his-4-912 delta correlates with an increase in wild-type HIS4 mRNA levels. The SPT2 gene is identical to SIN1, which codes for a factor genetically defined as a negative regulator of HO transcription. Mutations in SPT2/SIN1 suppress the effects of trans-acting mutations in SWI genes and of partial deletions in the C-terminal domain of the largest subunit of RNA polymerase II. Nuclear localization and protein sequence similarities suggested that the SPT2/SIN1 protein may be related to the nonhistone chromosomal protein HMG1. To assess the significance of this structural similarity and identify domains of SPT2 functionally important in the regulation of his4-912 delta, we have studied recessive and dominant spt2 mutations created by in vitro mutagenesis. We show here that several alleles carrying C-terminal deletions as well as point mutations in the C-terminal domain of the SPT2 protein exhibit a dominant suppressor phenotype. C-terminal basic residues necessary for wild-type SPT2 protein function which are absent from HMG1 have been identified. The competence of these mutant SPT2 proteins to interfere with the maintenance of the His- (Spt+) phenotype of a his4-912 delta SPT2+ strain is lost by deletion of internal HMG1-like sequences and is sensitive to the wild-type SPT2+ gene dosage. Using cross-reacting antipeptide polyclonal antibodies, we demonstrate that the intracellular level of the wild-type SPT2 protein is not affected in presence of dominant mutations and furthermore that the reversion of the dominance by internal deletion of HMG1-like sequences is not mediated by altered production or stability of the mutant polypeptides. Our results suggest that the products of dominant alleles directly compete with the wild-type protein. On the basis of primary sequence similarities, we propose that an HMG-box-like motif is required for SPT2 function in vivo and that this motif also is necessary for the dominant suppressor phenotype exhibited by some mutant SPT2 alleles.


Asunto(s)
Proteínas Cromosómicas no Histona/genética , Proteínas de Unión al ADN/genética , Genes Fúngicos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Alelos , Secuencia de Aminoácidos , Secuencia de Bases , Análisis Mutacional de ADN , Elementos Transponibles de ADN , Regulación Fúngica de la Expresión Génica , Genes Dominantes , Genes Supresores , Datos de Secuencia Molecular , Oligodesoxirribonucleótidos/química , Eliminación de Secuencia , Relación Estructura-Actividad , Transcripción Genética
12.
J Med Genet ; 43(2): 187-92, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15908568

RESUMEN

BACKGROUND: Placental mesenchymal dysplasia (PMD) is a distinct syndrome of unknown aetiology that is associated with significant fetal morbidity and mortality. Intrauterine growth restriction is common, yet, paradoxically, many of the associated fetuses/newborns have been diagnosed with Beckwith-Wiedemann syndrome (BWS). METHODS: We report two cases of PMD with high levels of androgenetic (complete paternal uniparental isodisomy) cells in the placenta and document, in one case, a likely androgenetic contribution to the fetus as well. RESULTS: The same haploid paternal complement found in the androgenetic cells was present in coexisting biparental cells, suggesting origin from a single fertilisation event. CONCLUSIONS: Preferential allocation of the normal cells into the trophoblast explains the absence of trophoblast overgrowth, a key feature of this syndrome. Interestingly, the distribution of androgenetic cells appears to differ from that reported for artificially created androgenetic mouse chimeras. Androgenetic mosaicism for the first time provides an aetiology for PMD, and may be a novel mechanism for BWS and unexplained intrauterine growth restriction.


Asunto(s)
Mesodermo/patología , Mosaicismo , Enfermedades Placentarias/genética , Enfermedades Placentarias/patología , Adulto , Andrógenos/metabolismo , Femenino , Genotipo , Humanos , Cariotipificación , Repeticiones de Microsatélite/genética , Embarazo
13.
Oncogene ; 16(17): 2165-76, 1998 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-9619825

RESUMEN

The Tax proteins of the oncovirinae viruses are phosphorylated transcriptional activators that exhibit oncogenic potential. The role of phosphorylation in their functional activities remains unknown. As a model for the Human T-cell leukemia virus type I (HTLV-I), Bovine Leukemia Virus (BLV) permits the characterization of viral replication and leukemogenesis in vivo. Here, we show that the BLV Tax protein is phosphorylated on serine residues 106 and 293 both in insect and in mammalian cells. These sites can also be efficiently phosphorylated by the cdc2 and MAP kinases in vitro. Mutation of these residues does not affect the capacity of the Tax protein to function as a transactivator. Indeed, the Tax proteins mutated at one or both serines increase LTR-directed viral transcription at levels similar to those obtained with wild-type Tax in cell culture. Moreover, inhibition of Tax phosphorylation by W7, a calmodulin antagonist, does not alter its transactivation activity. Thus, phosphorylation on serines 106 and 293 is not required for transactivation by Tax. However, simultaneous substitution of both serines into alanine residues destroys the capacity of Tax to cooperate with the Ha-ras oncogene to transform primary rat embryo fibroblasts and induce tumors in nude mice. When the serines were replaced with aspartic acid residues, the oncogenic potential of Tax was maintained indicating that the negative charge rather than the phosphate group itself was required for Tax oncogenicity. Finally, to assess the role of the serine residues in vivo, recombinant viruses which express the Tax mutants were constructed and injected into sheep. It appeared that the mutated proviruses replicate at levels similar to the wild-type virus in vivo. We conclude that Tax phosphorylation is dispensable for transactivation and viral replication in vivo but is required for its oncogenic potential in vitro.


Asunto(s)
Transformación Celular Viral/genética , Productos del Gen tax/genética , Productos del Gen tax/metabolismo , Virus de la Leucemia Bovina/genética , Activación Transcripcional/fisiología , Animales , Proteína Quinasa CDC2/metabolismo , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Bovinos , Línea Celular , Fibroblastos , Productos del Gen tax/antagonistas & inhibidores , Virus de la Leucemia Bovina/fisiología , Ratones , Ratones Desnudos , Mutagénesis Sitio-Dirigida , Fosforilación , Ratas , Ratas Endogámicas F344 , Serina/genética , Serina/metabolismo , Spodoptera , Replicación Viral/genética
14.
Cancer Radiother ; 19(2): 111-9, 2015 Apr.
Artículo en Francés | MEDLINE | ID: mdl-25573799

RESUMEN

Stereotactic hypofractionated radiotherapy after resection of brain metastasis is an alternative to whole brain radiotherapy. A high dose per fraction is associated with a risk of radiation necrosis. We present four cases of confirmed histological radiation necrosis. Differentiating recurrent tumour from radiation necrosis in this scenario is challenging. An enhancing area in magnetic resonance imaging (MRI) with a "cut bell pepper" appearance may suggest radiation necrosis. Advanced imaging modalities such as perfusion MR imaging and positron emission tomography can be useful. Dosimetric predictors of the occurrence of radiation necrosis after stereotactic hypofractionated radiotherapy are poorly understood and require prospective studies on larger cohorts.


Asunto(s)
Neoplasias Encefálicas/secundario , Encéfalo/efectos de la radiación , Carcinoma/secundario , Irradiación Craneana/efectos adversos , Melanoma/secundario , Traumatismos por Radiación/diagnóstico , Radiocirugia/efectos adversos , Encéfalo/patología , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/cirugía , Carcinoma/diagnóstico , Carcinoma/cirugía , Fraccionamiento de la Dosis de Radiación , Humanos , Imagen por Resonancia Magnética , Melanoma/diagnóstico , Melanoma/cirugía , Necrosis , Recurrencia Local de Neoplasia/diagnóstico , Tomografía de Emisión de Positrones , Complicaciones Posoperatorias/etiología , Traumatismos por Radiación/patología
15.
Cancer Radiother ; 19(6-7): 552-5, 2015 Oct.
Artículo en Francés | MEDLINE | ID: mdl-26321684

RESUMEN

Radiotherapy and chemotherapy are standard treatment of head and neck cancer alone or associated to surgical treatment. Early (during treatment or the following weeks) and late side effects contribute to malnutrition in this population at risk. In this context, nutritional support adapted by dietary monitoring and enteral nutrition (nasogastric tube or gastrostomy) are often necessary. The early identification of the patients with high malnutrition risk and requiring enteral nutrition is necessary to improve the tolerance and efficacy of treatment.


Asunto(s)
Neoplasias de Cabeza y Cuello/radioterapia , Apoyo Nutricional , Gastrostomía , Humanos , Intubación Gastrointestinal
16.
AIDS Res Hum Retroviruses ; 16(16): 1787-95, 2000 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-11080828

RESUMEN

The understanding of HTLV-induced disease is hampered by the lack of a suitable animal model allowing the study of both viral replication and leukemogenesis in vivo. Although valuable information has been obtained in different species, such as rabbits, mice, rats, and monkeys, none of these systems was able to conciliate topics as different as viral infectivity, propagation within the host, and generation of leukemic cells. An alternate strategy is based on the understanding of diseases induced by viruses closely related to HTLV-1, like bovine leukemia virus (BLV). Both viruses indeed belong to the same subfamily of retroviruses, harbor a similar genomic organization, and infect and transform cells of the hematopoietic system. The main advantage of the BLV system is that it allows direct experimentation in two different species, cattle and sheep.


Asunto(s)
Leucosis Bovina Enzoótica/virología , Virus de la Leucemia Bovina/genética , Virus de la Leucemia Bovina/patogenicidad , Animales , Bovinos , Enfermedades de los Bovinos/fisiopatología , Enfermedades de los Bovinos/virología , Leucosis Bovina Enzoótica/genética , Ovinos , Enfermedades de las Ovejas/fisiopatología , Enfermedades de las Ovejas/virología
17.
J Comp Psychol ; 110(1): 45-54, 1996 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8851552

RESUMEN

This study compared the direction of social learning in 2 populations of Barbados Zenaida doves (Zenaida aurita). One population (St. James) is territorial; it competes aggressively with conspecifics but scramble competes with heterospecifics. The other population (Deep Water Harbour) forages in large homospecific flocks. Field observations were conducted to quantify intraspecific and interspecific patterns of foraging association and aggression. Wild-caught doves from both areas were then tested on novel foraging tasks demonstrated by either a conspecific or a heterospecific tutor. In all experiments, St. James doves learned more readily from the heterospecific tutor (Carib grackle -Quiscalus lugubris-), whereas Deep Water Harbour doves learned more readily from the conspecific tutor. The type of competitive feeding interaction in the field (i.e., scramble vs. interference) appears to better predict the pattern of social learning in an experiment than does species identity.


Asunto(s)
Conducta Apetitiva , Columbidae , Conducta Competitiva , Conducta Imitativa , Medio Social , Agresión/psicología , Animales , Barbados , Femenino , Masculino , Especificidad de la Especie , Territorialidad
18.
Oecologia ; 64(3): 287-294, 1984 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28311441

RESUMEN

The flowers of the annual herb Impatiens capensis have distinct male and female phases. The male phase lasts four times as long as the female phase, and male flowers contain about 50% more nectar than female flowers. This suggests that the bulk of allocation to the flower is designed to ensure the dispersal of pollen rather than the fertilization of ovules. Honeybees, wasps and bumble bees all land on male flowers more often than would be expected by chance, and, having landed, wasps and bumble bees are more likely to enter a male flower than a female flower. The frequency of male flowers in the diet therefore exceeds their frequency in the population. This preference, although strong and consistent, is only partial, since some female flowers are included in the diet. We propose two hypotheses to account for the observed partial preference, the first based on competition between bees for flowers, and the second asserting that the bees detect nectar levels directly without using floral gender as a cue. The results of an experiment in which the most obvious gender cue, the androecium, was removed are consistent with the second hypothesis.

19.
Sci Total Environ ; 229(1-2): 121-4, 1999 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-10418166

RESUMEN

Popular shampoos were screened for their contents in trace elements, using ICP-MS detection in a semi-quantitative mode. Hair samples from volunteers were analyzed before and after hair washing with selected shampoos to demonstrate the effect of the contamination and the impact on occupational medicine. While some shampoos showed high levels of certain elements, the degree of contamination on the hair was found to be negligible. Only one shampoo tested, formulated with selenium sulfide, was found to seriously contaminate the hair.


Asunto(s)
Preparaciones para el Cabello/química , Cabello/química , Oligoelementos/análisis , Oligoelementos/farmacocinética , Humanos , Espectrometría de Masas
20.
Behav Processes ; 35(1-3): 163-71, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24896028

RESUMEN

Interspecific variation in learning and cognition is often accounted for by adaptive specialization, an ecological framework where variation between species in the environmental problems they face is thought to select for quantitatively and/or qualitatively different abilities. Adaptive specialization theory relies on the comparative method for testing its hypotheses and assumes a naturally selected basis for the predicted differences. This review examines social learning as a specialization to group-living and scramble feeding competition. It points out one important problem with current studies in the area, the lack of quantitative controls for confounding variables that may cause type 1 or 2 error in comparative tests. A linear regression technique is proposed to measure and remove interspecific differences on control tests for which there is no predicted adaptive specialization; as in other areas of comparative biology, the adaptive prediction is then made on the residual deviation from the regression of these confounding variables. Examples are given from research on opportunistic Columbids, the group-living feral pigeon Columbia livia, and the territorial Zenaida dove, Zenaida aurita.

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