Variabilidade na coordenação motora: uma abordagem centrada no delineamento gemelar

O propósito deste estudo foi estimar a contribuição dos fatores genéticos e ambientais na variabilidade do desempenho interindividual na coordenação motora. A amostra foi constituída por 64 pares de gêmeos portugueses, com idades entre cinco e 14 anos. Avaliou-se o desempenho da coordenação através das quatro provas da bateria KTK: equilíbrio à retaguarda (ER); saltos monopedais (SM); transposição lateral (TL); saltos laterais (SL). Calculou-se o coeficiente de correlação intraclasse (t), sendo estimada a contribuição dos fatores genéticos (a²), ambientais comuns (c²) e únicos (e²). Os resultados mostram valores de t mais elevados entre gêmeos monozigóticos, sugerindo presença de fatores genéticos. Entretanto, estimativas de a² foram baixas, variando entre 15% (TL) e 41% (SM), enquanto para c² situaram-se entre 46% (SL) e 58% (TL), e para e² entre 11% (SM) e 28% (TL). Conclui-se que fatores ambientais são responsáveis pela maior parcela de influência na variabilidade do desempenho na coordenação motora.El objetivo del presente estudio fue estimar la contribución de los factores genéticos y ambientales en la vEl objetivo del presente estudio fue estimar la contribución de los factores genéticos y ambientales en la variabilidad del desempeño interindividual en la coordinación motora. La muestra fue constituida por 64 pares de gemelos portugueses, con edades entre 5 y 14 años. Se evaluó el desempeño de la coordinación a través de las cuatro pruebas de la batería KTK: equilibrio a la retaguardia (ER); saltos monopedales (SM); transposición lateral (TL); saltos laterales (SL). Se calculó el coeficiente intraclase (t), siendo estimada la contribución de los factores genéticos (a²), ambientales comunes (c²) y únicos (e²). Los resultados muestran valores t mas elevados entre gemelos monocigóticos, sugiriendo la presencia de factores genéticos. Por otro lado, estimaciones de a² fueron bajas, variando entre 15% (TL) y 41% (SM), mientras para c² se sitúan entre 46% (SL) y 58% (TL), y para e² entre 11% (SM) y 28% (TL). Se concluye que factores ambientales son responsables por la mayor porción de influencia de la variabilidad del desempeño en la coordinación motora.The purpose of this study was to estimate the contribution of environmental and genetic factors on the variability of interindividual performance in motor coordination. Sample comprised 64 twin pairs, aged 5 to 14 years old, from Portugal. Motor coordination was evaluated by KTK battery: backward balance (ER); hopping on one leg (SM); shifting platforms (TL); jumping sideways (SL). Intraclass correlation coefficient (t) was calculated. Contributions of genetic (a²), shared (c²) and unique environmental (e²) factors were estimated. Our results showed t values higher in monozygotic twins, suggesting the presence of genetic factors. Nevertheless, a² estimates were low, ranging from 15% (TL) to 41% (SM), while to common environment (c²) ranged from 46% (SL) to 58% (TL), and unique effects ranged from 11% (SM) to 28% (TL). These results suggest that environmental factors are responsible for the greatest part of influence on variability of interindividual performance in motor coordination tests

An ab initio study of PuO 2±0.25 , UO 2±0.25 , and U 0.5 Pu 0.5 O2±0.25

Hybrid density functional theory has been used to systematically study the electronic, geometric, and magnetic properties of strongly correlated materials PuO2±x, UO2±x, and U0.5Pu0.5O2±x with x = 0.25. The calculations have been performed using the all-electron full- potential linearized augmented plane wave plus local orbitals basis (FP-L/APW+lo) method. Each compound has been studied at the ferromagnetic (FM) and anti-ferromagnetic (AFM) configurations with and without spin-orbit coupling (SOC) and full geometry optimizations. The optimized lattice constants, bulk moduli, and band gaps are reported. Total energy calculations indicate that the ground states are AFM for all compounds studied here and the band gaps are typically higher than 1.0 eV, characteristic of semiconductors. The total energy is lowered significantly and the band gaps increase with the inclusion of SOC. The chemical bonds between the actinide metals and oxygen atoms are primarily ionic in character

The Functions of RNA-Dependent RNA Polymerases in Arabidopsis

One recently identified mechanism that regulates mRNA abundance is RNA silencing, and pioneering work in Arabidopsis thaliana and other genetic model organisms helped define this process. RNA silencing pathways are triggered by either self-complementary fold-back structures or the production of double-stranded RNA (dsRNA) that gives rise to small RNAs (smRNAs) known as microRNAs (miRNAs) or small-interfering RNAs (siRNAs). These smRNAs direct sequence-specific regulation of various gene transcripts, repetitive sequences, viruses, and mobile elements via RNA cleavage, translational inhibition, or transcriptional silencing through DNA methylation and heterochromatin formation. Early genetic screens in Arabidopsis were instrumental in uncovering numerous proteins required for these important regulatory pathways. Among the factors identified by these studies were RNA-dependent RNA polymerases (RDRs), which are proteins that synthesize siRNA-producing dsRNA molecules using a single-stranded RNA (ssRNA) molecule as a template. Recently, a growing body of evidence has implicated RDR-dependent RNA silencing in many different aspects of plant biology ranging from reproductive development to pathogen resistance. Here, we focus on the specific functions of the six Arabidopsis RDRs in RNA silencing, their ssRNA substrates and resulting RDR-dependent smRNAs, and the numerous biological functions of these proteins in plant development and stress responses