Ambiente matemático de niños y niñas chilenos: Factores que explican las actividades matemáticas en el hogar / Home math environment of Chilean boys and girls: Factors that explain home math activities

Resumen Introducción: el estudio analizó (a) las diferencias entre madres y padres en sus actividades matemáticas en el hogar y en otros factores del ambiente matemático (actitudes, ansiedad, creencias y expectativas matemáticas) y (b) la asociación entre los factores del ambiente matemático y las actividades matemáticas en el hogar. Método: participaron 266 familias de niños y niñas chilenos de primer a tercer grado de primaria (edad promedio = 93.35 meses, DE = 11.45 meses). Ambos padres contestaron un cuestionario sobre matemáticas en el hogar. Resultados: las madres reportaron realizar actividades matemáticas con mayor frecuencia que los padres. Análisis de ecuaciones estructurales mostraron que las actividades matemáticas realizadas por los padres se relacionaron con sus creencias, actitudes y expectativas matemáticas; mientras que las de las madres se relacionaron con sus creencias, actitudes y género de los niños. Conclusiones: los hallazgos aportan a la comprensión del ambiente matemático en el hogar.

Abstract Introduction: The study analyzes (a) the differences between mothers and fathers in their home math activities and home math environment factors (math attitudes, anxiety, beliefs, and expectations) and (b) the associations among the home math environment factors and home math activities of Chilean families. Method: Participants were 266 families of boys and girls attending grades 1-3 (mean age = 93.35 months, DS = 11.45 months). Both parents of each child independently answered a home math questionnaire. Results: Mothers reported doing more math activities with their children than fathers. The structural equation model analyses showed that the frequency with which fathers engage in home math activities was related to their math beliefs, attitudes, and expectations, whereas maternal home math activities were related to their beliefs, attitudes, and the gender of the child. Conclusions: The findings contribute to the understanding of the home math environment.

Trends of maxillofacial trauma: An update from the prospective register of a multicenter study in emergency services of Chile.

BACKGROUND: Determine the behavior of the maxillofacial trauma of adults treated in 3 tertiary care centers in the central zone of Chile. MATERIAL AND METHODS: descriptive, cross-sectional, multicenter study, based on the prospective records of maxillofacial trauma cases attended between May 2016 and April 2017 by dental and maxillofacial clinical teams of Adult Emergency Units of hospitals Dr. Sótero del Río (metropolitan region), Carlos Van Buren and Dr. Gustavo Fricke (region V). Age, sex, date of occurrence, type of trauma according to ICD-10, etiology, legal medical prognosis and associated injuries were recorded, stratifying by sex and age. Chi square and unpaired Wilcoxon tests were used to compare by groups. RESULTS: 2.485 cases and 3.285 injuries were investigated. The male: female ratio was 1.7: 1 with age under 30 predominant, followed by older adults. Variability was observed in the yearly, weekly and daily presentation. The highest frequencies were in January and September, weekends and at night. The main etiologies were violence (42.3%), falls (13.1%) and road traffic crashes (12.9%) with differences by age and sex (p <0.05). 31,9% of the injuries occurred in hard tissue, being fractures in nasal bones predominant (S02.2). CONCLUSIONS: the profile of the maxillofacial trauma in Chile seems to be mixed by age, affecting young people and the elderly. The male sex predominates; the main cause, which varies by age group, is violence. Their surveillance is possible from hospital emergency records.

N-acetyl-cysteine blunts 6-hydroxydopamine- and L-buthionine-sulfoximine-induced apoptosis in human mesenchymal stromal cells.

Parkinson disease (PD) is characterized by the loss of dopaminergic (DAergic) neurons linked to environmental toxicants that cause oxidative stress (OS). The aim of this investigation was to establish the molecular response of human mesenchymal stroma cells (MSCs) depleted of glutathione (GSH) by the specific inhibitor L-buthionine-sulfoximine (BSO) to 6-hydroxydopamine (6-OHDA) and/or N-acetylcysteine (NAC) co-treatment. We found that treatment with BSO (10 mM) plus 6-OHDA (200 µM) induced apoptosis in MSCs through an oxidative stress (OS) mechanism involving H2O2, reflected by the detection of dichlorofluorescein-positive (DCF+) cells and oxidation of DJ-1 Cys106-SH into DJ-1 Cys106-SO3; an almost complete reduction in glutathione peroxidase 1 (GPX1) expression; activation of the transcription factor c-JUN, the pro-apoptotic protein BAX and BH-3-only protein PUMA; loss of mitochondrial membrane potential (∆Ψm); activation of the protease caspase-3 (CASP3) and apoptosis-inducing factor (AIF); chromatin condensation; and DNA fragmentation. Strikingly, co-treatment of MSCs with NAC (5 mM) and BSO + 6-OHDA significantly reduced the expression of OS and cell death markers but were unable to restore the expression of GPX1 compared to the expression in untreated or treated cells with NAC only. These findings highlighted the importance of the maintenance of the GSH-dependent (e.g., GPX1, GSH synthesis) and -independent (e.g., ROS scavenger molecules and thiol reducing activity) antioxidant systems (e.g., NAC) in the protection of MSCs from detrimental stress stimuli, thereby increasing the survival of stromal cells.

Epidemiology and natural history of cutaneous squamous cell carcinoma in recessive dystrophic epidermolysis bullosa patients: 20 years' experience of a reference centre in Spain.

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is the leading cause of death in patients with recessive dystrophic epidermolysis bullosa (RDEB). We provide the management and prognosis of cSCC in RDEB patients at a Spanish reference center. MATERIALS AND METHODS: We retrospectively included patients with RDEB attended in La Paz University Hospital from November 1988 to October 2018. RESULTS: Fourteen patients developed at least one cSCC. Tumors were predominantly well differentiated. Nearly half of the tumors have recurred. Median time to first recurrence was 23.4 months (95% CI: 17.2-29.5). Five patients have developed distant metastases. Median overall survival (mOS) was 136.5 months since the diagnosis of the first cSCC (95% CI: 30.6-242.3). When distant metastases occurred, mOS was 6.78 months (95% CI: 1.94-11.61). CONCLUSIONS: cSCC is a life-threatening complication of RDEB patients. Although tumors are usually well differentiated, they tend to relapse. This is the first Spanish report of cSCC arising in RDEB patients.

Chilean kindergarten children's beliefs about mathematics: Family matters.

This study examines the relations among parental beliefs and practices about mathematics, children's beliefs about mathematics, participants' gender, and family socioeconomic status (SES). The study was conducted in Chile, a country with significant gender gaps in standardized test results in mathematics, with boys receiving significantly higher scores than girls. One hundred eighty Chilean kindergarteners (Mage = 5.6 years) of low and high SES completed both implicit and explicit measures of their beliefs about mathematics. Children's mothers and fathers also completed adult versions of these tests, as well as measures of home numeracy practices. This combination of child and parental assessments (both mother and father), including both implicit and explicit measures, provided a wider range of measures than in previous studies. On implicit measures of math-gender stereotypes, boys showed the math = boy stereotype significantly more strongly than girls did. Both fathers and mothers showed this stereotype on both implicit and explicit measures. Fathers also linked me = math (math self-concept) more strongly than mothers on both implicit and explicit measures. Kindergarten girls' implicit math self-concept was explained by a combination of parents' math self-concepts and SES. Taken together, these results show that by 5 years of age children are already developing beliefs about "who does math" in their culture, and that parental beliefs and practices are significantly linked to children's stereotypes and self-concepts about mathematics before they enter formal schooling. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

PARKIN overexpression in human mesenchymal stromal cells from Wharton's jelly suppresses 6-hydroxydopamine-induced apoptosis: Potential therapeutic strategy in Parkinson's disease.

BACKGROUND AIMS: Stem cell transplantation is an excellent option for regenerative or replacement therapy. However, deleterious microenvironmental and endogenous factors (e.g., oxidative stress) compromise ongoing graft survival and longevity. Therefore, (transient or stable) genetically modified cells may be reasonably thought to resist oxidative stress-induced damage. Genetic engineering of mesenchymal stromal cells (MSCs) obtained from Wharton's jelly tissue may offer some therapeutic potential. PARKIN is a multifunctional ubiquitin ligase able to protect dopaminergic cells against stress-related signaling. We, therefore, evaluated the effect of the neurotoxicant 6-hydroxydopamine (6-OHDA) on regulated cell death signaling in MSCs and investigated whether overexpression of PARKIN in MSCs was capable of modulating the effect of 6-OHDA. METHODS: We transiently transfected Wharton's jelly-derived MSCs with an mCherry-PARKIN vector using the Lipofectamine LTX method. Naïve MSCs and MSCs overexpressing PARKIN were exposed to increasing concentrations of 6-OHDA. We used light and fluorescence microscopy, flow cytometry, immunocytochemistry staining, in-cell Western and Western blot analysis. RESULTS: After 12-24 h of 6-OHDA exposure, we detected dichlorofluorescein (DCF)-positive cells (80%) indicative of reactive oxygen species (H2O2) production, reduced cell viability (40-50%), decreased mitochondrial membrane potential (ΔΨm, ~35-45%), DNA fragmentation (18-30%), and G1-arrested cell cycle in the MSCs. 6-OHDA exposure increased the expression of the transcription factor c-JUN, increased the expression of the mitochondria maintenance Phosphatase and tensin homologue-induced putative kinase 1 (PINK1) protein and increased the expression of pro-apoptotic PUMA, caspase-3 and apoptosis-inducing factor (AIF). 6-OHDA exposure also significantly augmented the oxidation of the oxidative stress sensor, DJ-1. Overexpression of PARKIN in MSCs not only significantly reduced the expression of cell death and oxidative stress markers but also significantly reduced DCF-positive cells (~50% reduction). DISCUSSION: 6-OHDA induced apoptosis in MSCs via generation of H2O2, activation of c-JUN and PUMA, mitochondrial depolarization and nuclei fragmentation. Our findings suggest that PARKIN protects MSCs against 6-OHDA toxicity by partly interacting with H2O2, reducing the expression of c-JUN, PUMA, AIF and caspase-3, and maintaining the mitochondrial ΔΨm.

Fast transdifferentiation of human Wharton's jelly mesenchymal stem cells into neurospheres and nerve-like cells.

BACKGROUND: The human mesenchymal stem cells derived from Wharton's jelly tissue (hWJ-MSCs) represent a tool for cell-based therapies and regenerative medicine. hWJ-MSCs form neurospheres (NSs) within 3-7 days. No data is available to establish the neuro-phenotypic markers and time of formation of nerve-like (NLCs) and glial cells from NSs derived from hWJ-MSCs. NEW METHOD: hWJ-MSCs were incubated with Fast-N-Spheres medium for 24 and 72h. The new formed NSs were in turn incubated with forskolin in neurogenic NeuroForsk medium for 1-7days. RESULTS: hWJ-MSCs cultured with Fast-N-Spheres medium trans-differentiated into NSs in just 24h compared to 72h for hWJ-MSCs cultured with classic growth factor medium. The NSs generated from the Fast-N-Spheres medium expressed reduced levels SOX2, OCT4 and NANOG, as markers of pluripotency compared to undifferentiated hWJ-MSCs. The formed NSs exposed to NeuroForsk medium differentiated into NLCs in 4days as evidenced by high levels of protein expression of the neuronal markers, and no expression of the glial marker GFAP. COMPARISON WITH EXISTING METHOD(S): Currently, the formation and harvest of NSs is expensive and time consuming. Published protocols require 3-7days to form NSs from whole human umbilical cord MSCs. We report for the first time, to our knowledge, the differentiation of NSs-derived from hWJ-MSCs into NLCs. CONCLUSIONS: The fastest method to obtain NSs and NLCs from hWJ-MSCs takes only five days using the two-step incubation media Fast-N-Spheres and NeuroForsk.

Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera, Curculionidae) from Brazil.

Stenocyphus Marshall, 1922 (Entiminae, Naupactini) includes three species: the type species S. bituberosus (Gyllenhal, 1833), S. tuberculatus (Hustache, 1938), comb. n. herein transferred from Neoericydeus Hustache, 1938, and S. sextuberosus sp. n. The genus is endemic to the Atlantic forests of the states of Espirito Santo, Rio de Janeiro and São Paulo, Brazil andis mainly characterized by the presence of humped elytra bearing large conical tubercles on the intervals 5, or 3 and 5, or 3, 5 and 7. It shares some external morphological characters with Hadropus Schoenherr, 1826 and the Brazilian species of Cyrtomon Schoenherr 1823, but its phylogenetic position is uncertain. Herein we provide a diagnostic key to separate Stenocyphus from those genera, generic and species redescriptions or descriptions, a key to species, habitus photographs, line drawings of genitalia, and a discussion of the patterns of elytral tubercles in unrelated genera of Neotropical broad-nosed weevils.

On the presence of five species of naupactini (Coleoptera: Curculionidae) damaging soybean in Brazil.

We report five broad-nosed weevils of the tribe Naupactini, Naupactus leucoloma Boheman, Naupactus minor (Buchanan), Naupactus peregrinus (Buchanan), Naupactus tremolerasi Hustache and Pantomorus viridisquamosus (Boheman) (Coleoptera: Curculionidae) damaging soybean plants in the state of Rio Grande do Sul, Brazil. Some of these species are recorded for the first time in Brazil, and they all belong to species groups naturally distributed in the prairies of southern Brazil, Uruguay, Central Argentina and Paraguay. Three of them have been introduced, established and expanded in other countries outside South America. The five species in conjunction with other native species of Naupactini could cause severe damages to soybean crops if the root-feeding larvae attack young growing plants.

Potential geographic distributions and successful invasions of parthenogenetic broad-nosed weevils (Coleoptera: Curculionidae) native to South America.

Ten species of parthenogenetic broad-nosed weevils (Coleoptera: Curculionidae: Entiminae) native to Argentina, southern Brazil, and Uruguay were selected for niche modeling analysis based on climatic data and altitude, to evaluate their potential range expansion inside and outside South America. The selected species belong to five genera of the tribe Naupactini affecting economically important crops. Until present, five of the 10 species analyzed here have invaded prairies and steppes of countries outside South America (Australia, New Zealand, Mexico, United States, and South Africa): Aramigus tessellatus (Say), Atrichonotus sordidus (Hustache), Atrichonotus taeniatulus (Berg), Naupactus leucoloma Boheman, and Naupactus peregrinus (Buchanan). Our niche modeling analyses performed with MAXENT demonstrated that these areas would be also suitable for Aramigus conirostris (Hustache), Eurymetopus fallax (Boheman), Pantomorus auripes Hustache, Pantomorus ruizi (Brèthes), and Pantomorus viridisquamosus (Boheman), consequently, they also have the potential to invade areas outside their native ranges, mainly in southeastern United States, some European countries (e.g., Portugal, France, and southern England), South Africa, New Zealand, and southeastern Australia. All the studied species share similar environmental requirements, the most important variables being the Mean Temperature of Driest Quarter, the Annual Mean Temperature and Isothermality. Long distance dispersal through commercial trade, and parthenogenetic reproduction would increase the threat of these weevils to crop production worldwide.

Cystic echinococcosis: a disease mimicking cancer in a non-endemic country report of two cases / Equinococosis quística: una enfermedad con apariencia de cáncer en un país no endémico: reporte de eos easos

Echinococcosis is a parasitic disease that involves dogs as definitive host and sheep as intermediate host. Humans become infected incidentally through fecal-oral contact, particularly in the course of playful and close contact with an infected dog. Mexico is considered a region that is virtually free of cystic echinoccocosis. This manuscript describes two cases that were referred to a tertiary-care oncology hospital with a diagnosis of cancer. In one case, the presumptive diagnosis was liver cancer because abdominal ultrasonography revealed a low-density mass in the right hepatic lobe. Drainage was performed and cytologic examination of the fluid showed multiple Echinococcus cyst as well as prostoscolex. The case was resolved with percutaneous drainage and administration of albendazole for two months. In the second case, the patient was referred with a diagnosis of disseminated cervical cancer. A cyst was identified in the upper right lung lobe; a diagnostic puncture was performed showing an Echinococcus cyst. This resolved solely with two months of albendazole administration.

La equinococosis, conocida también como hidatidosis, es una enfermedad parasitaria que comprende a los perros como hospedador definitivo y a las ovejas como huésped intermedio. Los seres humanos se infectan casualmente por contacto feco-oral, particularmente al jugar y estar en estrecho contacto con un perro infectado. México es considerado una región que está prácticamente libre de equinococosis quística. Este trabajo describe dos casos que fueron referidos con un diagnóstico de cáncer a un hospital oncológico de atención terciaria. En un caso, el diagnóstico presuntivo fue cáncer del hígado, porque la ultrasonografía abdominal reveló una masa de baja densidad en el lóbulo hepático derecho. Se hizo un drenaje y el examen citológico del fluido mostró quistes múltiples de equinococos así como la presencia de protoescólex. El caso se resolvió con drenaje percutáneo y administración de albendazol durante dos meses. En el segundo caso, la paciente fue remitida con un diagnóstico de cáncer cervical diseminado. Se identificó un quiste en el lóbulo superior de pulmón derecho. La punción diagnóstica realizada reveló un quiste equinocócico, que se resolvió simplemente con dos meses de administración de albendazol.

Cystic echinococcosis: a disease mimicking cancer in a non-endemic country report of two cases.

Echinococcosis is a parasitic disease that involves dogs as definitive host and sheep as intermediate host. Humans become infected incidentally through fecal-oral contact, particularly in the course of playful and close contact with an infected dog. Mexico is considered a region that is virtually free of cystic echinoccocosis. This manuscript describes two cases that were referred to a tertiary-care oncology hospital with a diagnosis of cancer. In one case, the presumptive diagnosis was liver cancer because abdominal ultrasonography revealed a low-density mass in the right hepatic lobe. Drainage was performed and cytologic examination of the fluid showed multiple Echinococcus cyst as well as prostoscolex. The case was resolved with percutaneous drainage and administration of albendazole for two months. In the second case, the patient was referred with a diagnosis of disseminated cervical cancer A cyst was identified in the upper right lung lobe; a diagnostic puncture was performed showing an Echinococcus cyst. This resolved solely with two months of albendazole administration.

Hydration and nutrition at the end of life: a systematic review of emotional impact, perceptions, and decision-making among patients, family, and health care staff.

BACKGROUND: Decrease in oral intake, weight loss, and muscular weakness in the last phases of a terminal illness, particularly in the context of the cachexia-anorexia syndrome, can be an important source of anxiety for the triad of patient, family, and health staff. METHODS: The present literature review examines the emotional impact of reduced oral intake as well as perceptions and attitudes toward assisted nutrition and hydration for terminally ill patients(1) at the end of life, among patients, family, and health care staff. We have identified the ways in which emotional and cultural factors influence decision-making about assisted nutrition and hydration. RESULTS: Lack of information and misperceptions of medically assisted nutrition and hydration can play a predominant role in the decision to begin or suspend nutritional or hydration support. CONCLUSIONS: Our literature review reveals that these social, emotional, and clinical misperception elements should be considered in the decision-making processes to help the triad develop functional forms of care at this final stage of life. Copyright © 2011 John Wiley & Sons, Ltd.

Obrieniolus, a new monotypic genus of Naupactini (Coleoptera, Curculionidae, Entiminae) from the Peruvian Andes and its phylogenetic placement.

A new monotypic genus of Naupactini (Coleoptera: Curculionidae), Obrieniolus del Río is described based on the new species Obrieniolus robustus del Río, endemic to Peru. This genus is easily recognized by the black, denuded and shiny integument, with imbricate microsculpture and the rounded body, with short, cordiform and moderately convex elytra. According to a cladistic analysis based on 69 continuous and discrete morphological characters, the new genus is the sister taxon of a group formed by Amitrus Schoenherr, Trichocyphus Heller, Amphideritus Schoenherr, Asymmathetes Wibmer & O'Brien and Galapaganus Lanteri. The paper includes habitus photographs, line drawings of genitalia, mouthparts, and other external features of taxonomic value, and a dichotomous key to the genera of Naupactini distributed in the South American Transition Zone.

The effects of polyphenols on survival and locomotor activity in Drosophila melanogaster exposed to iron and paraquat.

Parkinson's disease (PD) is a common progressive neurodegenerative disorder, for which at present no causal treatment is available. On the understanding that the causes of PD are mainly oxidative stress and mitochondrial dysfunction, antioxidants and other drugs are expected to be used. In the present study, we demonstrated for the first time that pure polyphenols such as gallic acid, ferulic acid, caffeic acid, coumaric acid, propyl gallate, epicatechin, epigallocatechin, and epigallocatechin gallate protect, rescue and, most importantly, restore the impaired movement activity (i.e., climbing capability) induced by paraquat in Drosophila melanogaster, a valid model of PD. We also showed for the first time that high concentrations of iron (e.g. 15 mM FeSO(4)) are able to diminish fly survival and movement to a similar extent as (20 mM) paraquat treatment. Moreover, paraquat and iron synergistically affect both survival and locomotor function. Remarkably, propyl gallate and epigallocatechin gallate protected and maintained movement abilities in flies co-treated with paraquat and iron. Our findings indicate that pure polyphenols might be potent neuroprotective agents for the treatment of PD against stressful stimuli.

The cannabinoid CP55,940 prolongs survival and improves locomotor activity in Drosophila melanogaster against paraquat: implications in Parkinson's disease.

Cannabinoids have been shown to function as protective agents via receptor-independent and/or receptor-dependent mechanisms against stressful conditions. However, the neuroprotective mechanism of cannabinoids is far from conclusive. Therefore, the genuine antioxidant impact of cannabinoids in vivo is still uncertain. In this study, we demonstrate for the first time that CP55,940, a nonselective CB(1)/CB(2) cannabinoid receptor agonist, significantly protects and rescues Drosophila melanogaster against paraquat (PQ) toxicity via a receptor-independent mechanism. Interestingly, CP55,940 restores the negative geotaxis activity (i.e., climbing capability) of the fly exposed to PQ. Moreover, Drosophila fed with (1-200 microM) SP600125, a specific inhibitor of the stress responsive Jun-N-terminal kinase (JNK) signaling, and 20 mM PQ increased survival percentage and movement function (i.e., climbing capability) when compared to flies only treated with PQ. Taken together our results suggest that exogenous antioxidant cannabinoids can protect against and rescue from locomotor dysfunction in wild type (Canton-S) Drosophila exposed to stress stimuli. Therefore, cannabinoids may offer promising avenues for the design of molecules to prevent, delay, or ameliorate the treatment of population at high risk of suffering Parkinson disease.

Cognitive slowing in cognitive-motordisorder associated to type 1 humanimmunodeficiency virus: tr and P300

Introduction. Reaction time (RT) deficit exhibited by HIV-1 asymptomatic seropositive individuals cannot alwaysbe explained by the effect of a cognitive slowing single factor.Evidence exists that decisional and peripheral componentsof RT may have differential slowing.Objectives. To assess the hypothesis of a cognitive slowing single factor as the main responsible for RT slowingin these subjects. Methodology. Thirty two (32) HIV-1 neurologically asymptomatic seropositive individuals were compared to 29 seronegative controls in two discriminative reaction time tasks (DRT) having increased cognitive difficulty but equal motorresponse demands. P300 component of the event-related potential was recorded simultaneously. RT, PPI, errors, and P300 latency were assessed using ANOVA. Results: Seropositives were slower than controls in RT,made more errors and showed delayed latencies of P300 in both tasks. However, while the increase of RT from the easier to the more difficult task was additive, the increase of P300 latencies was multiplicative. Conclusions. These results reveal differences in patternsof slowing between central and motor information processing mechanisms. Such results suggest that a singlecommon factor is not enough to explain cognitive slowing in HIV-1 seropositive subjects(AU)

Introducción. Los déficit de tiempo de reacción (TR) en los sujetos infectados por el virus de inmunodeficienciahumana tipo 1 (VIH-1) en las etapas iniciales de la infección no parecen siempre comprensibles por la acciónde un factor general de enlentecimiento cognitivo. Existen evidencias que indican que los componentes dela decisión y periféricos del TR pueden lentificarse diferencialmente.Objetivos. Evaluar la acción de un factor general de enlentecimiento cognitivo como causa principal de incrementodel TR en estos sujetos. Métodos. Treinta y dos sujetos seropositivos al VIH-1 neurológicamente asintomáticos fueron comparados con 29 controles seronegativos en dos tareas de tiempo de reacción discriminativo (TRD) de dificultad creciente, perocon iguales demandas de respuesta. Simultáneamente se registró el componente P300 del potencial evocadopor las tareas. El TR, el IPP, los errores y la latencia del componente P300 fueron comparados mediante ANOVA.Resultados. Los seropositivos fueron más lentos, cometieron más errores y exhibieron latencias más prolongadasque los controles, pero mientras que el incremento del TR entre tareas fue aditivo, el de latencia de P300 fuemultiplicativo. Conclusiones. Los resultados revelan una disociaciónen el patrón de enlentecimiento de los mecanismos centrales y los de producción de respuesta. Tales resultadossugieren que un factor general no es suficiente paraexplicar el enlentecimiento cognitivo de estos(AU)

Cognitive slowing in cognitive-motor disorder associated to type 1 human immunodeficiency virus: TR and P300.

INTRODUCTION: Reaction time (RT) deficit exhibited by HIV-1 asymptomatic seropositive individuals cannot always be explained by the effect of a cognitive slowing single factor. Evidence exists that decisional and peripheral components of RT may have differential slowing. OBJECTIVES: To assess the hypothesis of a cognitive slowing single factor as the main responsible for RT slowing in these subjects. METHODOLOGY: Thirty two (32) HIV-1 neurologically asymptomatic seropositive individuals were compared to 29 seronegative controls in two discriminative reaction time tasks (DRT) having increased cognitive difficulty but equal motor response demands. P300 component of the event-related potential was recorded simultaneously. RT, PPI, errors, and P300 latency were assessed using ANOVA. RESULTS: Seropositives were slower than controls in RT, made more errors and showed delayed latencies of P300 in both tasks. However, while the increase of RT from the easier to the more difficult task was additive, the increase of P300 latencies was multiplicative. CONCLUSIONS: These results reveal differences in patterns of slowing between central and motor information processing mechanisms. Such results suggest that a single common factor is not enough to explain cognitive slowing in HIV-1 seropositive subjects.

The influence of radical architecture on cadmium bioaccumulation in the black mangrove, Avicennia germinans L.

Two groups of Avicennia germinans plants with differences in the radical architecture were exposed under hydroponic conditions to 95ppm of cadmium (Cd) for a period of 24h. Later, Cd concentration in roots, stems and leaves was determined by graphite furnace atomic absorption spectrophotometry. Our results showed that, for both groups of plants, the roots accumulated higher concentration of Cd as compared to stems and leaves, though, the plants of group B displayed enhanced radical architecture, better growth performance, and lower Cd concentration as compared to plants of group A. In contrast, low values of leaves/roots Cd transportation index, and bioaccumulation factor were found in plants of group B. These results suggest that the higher radical architecture developed in plants of group B might better adjust the uptake of Cd as a result of an integrated network of multiple response processes for instances, production of organic acids, antioxidative replay, cell-wall lignification and/or suberization. Further studies will be focused in understanding the role of the radical system in mangrove plants with the rhizosphere activation and root adsorption to soil Cd under natural conditions.