Do synergies improve accuracy? A study of speed-accuracy trade-offs during finger force production

We explored possible effects of negative covariation among finger forces in multifinger accurate force production tasks on the classical Fitts's speed-accuracy trade-off. Healthy subjects performed cyclic force changes between pairs of targets ""as quickly and accurately as possible."" Tasks with two force amplitudes and six ratics of force amplitude to target size were performed by each of the four fingers of the right hand and four finger combinations. There was a close to linear relation between movement time and the log-transformed ratio of target amplitude to target size across all finger combinations. There was a close to linear relation between standard deviation of force amplitude and movement time. There were no differences between the performance of either of the two ""radial"" fingers (index and middle) and the multifinger tasks. The ""ulnar"" fingers (little and ring) showed higher indices of variability and longer movement times as compared with both ""radial"" fingers and multifinger combinations. We conclude that potential effects of the negative covariation and also of the task-sharing across a set of fingers are counterbalanced by an increase in individual finger force variability in multifinger tasks as compared with single-finger tasks. The results speak in favor of a feed-forward model of multifinger synergies. They corroborate a hypothesis that multifinger synergies are created not to improve overall accuracy, but to allow the system larger flexibility, for example to deal with unexpected perturbations and concomitant tasks.

Unconventional metallic behavior and superconductivity in the K-Mo-O system

Transport properties and magnetization measurements of the K(x)MoO(2-delta) (0 <= x <= 0.25) compound are reported. The compound crystallizes in the oxygen deficient MoO(2) monoclinic structure with potassium atoms occupying interstitial positions. An unconventional metallic behavior with power-law temperature dependence is related to a magnetic ordering. Superconducting transition with small volume fraction is also observed near 7 K for a sample with low potassium composition.

Functionalized adamantane: Building blocks for nanostructure self-assembly

We report first-principles calculations on the electronic and structural properties of chemically functionalized adamantane molecules, either in isolated or crystalline forms. Boron and nitrogen functionalized molecules, aza-, tetra-aza-, bora-, and tetra-bora-adamantane, were found to be very stable in terms of energetics, consistent with available experimental data. Additionally, a hypothetical molecular crystal in a zincblende structure, involving the pair tetra-bora-adamantane and tetra-aza-adamantane, was investigated. This molecular crystal presented a direct and large electronic band gap and a bulk modulus of 20 GPa. The viability of using those functionalized molecules as fundamental building blocks for nanostructure self-assembly is discussed.

Electronic properties and hyperfine fields of nickel-related complexes in diamond

We carried out a first-principles investigation on the microscopic properties of nickel-related defect centers in diamond. Several configurations, involving substitutional and interstitial nickel impurities, have been considered either in isolated configurations or forming complexes with other defects, such as vacancies and boron and nitrogen dopants. The results, in terms of spin, symmetry, and hyperfine fields, were compared with the available experimental data on electrically active centers in synthetic diamond. Several microscopic models, previously proposed to explain those data, have been confirmed by this investigation, while some models could be discarded. We also provided insights into the microscopic structure of several of those centers.

Selective activation of the rectus abdominis muscle during low-intensity and fatiguing tasks

In order to understand the potential selective activation of the rectus abdominis muscle, we conducted two experiments. In the first, subjects performed two controlled isometric exercises: the curl up (supine trunk raise) and the leg raise (supine bent leg raise) at low intensity (in which only a few motor units are recruited). In the second experiment, subjects performed the same exercises, but they were required to maintain a certain force level in order to induce fatigue. We recorded the electromyographic (EMG) activities of the lower and upper portions of the rectus abdominis muscle during the exercises and used spatial-temporal and frequency analyses to describe muscle activation patterns. At low-intensity contractions, the ratio between the EMG intensities of the upper and lower portions during the curl up exercise was significantly larger than during the leg raise exercise (p = 0.02). A cross-correlation analysis indicated that the signals of the abdominal portions were related to each other and this relation did not differ between the tasks (p = 0.12). In the fatiguing condition, fatigue for the upper portion was higher than for the lower portion during the curl up exercise (p = 0.008). We conclude that different exercises evoked, to a certain degree, individualized activation of each part of the rectus abdominis muscle, but different portions of the rectus abdominis muscle contributed to the same task, acting like a functional unit. These results corroborate the relevance of varying exercise to modify activation patterns of the rectus abdominis muscle.

Host status of some selected Brazilian upland rice cultivars to Meloidogyne incognita race 4 and Rotylenchulus reniformis

Nowadays, rice is among the most preferred crops for rotation with soybean and cotton in the large producing areas of Central Brazil. Nevertheless, the host status of the Brazilian upland rice cultivars for Meloidogyne incognita race 4 and Rotylenchulus reniformis has not been investigated and remains unknown. This study dealt with the assessment of the host response of some selected Brazilian upland rice cultivars to these nematodes under glasshouse conditions. The host status for each tested interaction was based on the nematode reproduction factor (RF) and number of nematodes (g root)(-1). Two experiments with M. incognita race 4, referred to as trial I (initial population (IP) = 4000) and trial 2 (IP = 800), included, respectively, 14 cultivars (cvs AN Cirad 141, BRS Monarca, BRS Primavera, AN Cambara, BRS Pepita, BRS Curinga, BRS Sertaneja, IAPAR 9, IAPAR 62, IAPAR 63, IAPAR 64, IAPAR 117, IAC 201, IAC 202) and 19 cultivars (the same ones in Experiment 1 plus cvs BRS Maravilha, BRS Talento, BRS Bonanca, Ricetec Ecco, BRS Soberana). Except for cv. BRS Pepita, rated as resistant, the cultivars were rated as susceptible or moderately susceptible (RF means ranged from 1.09 to 12.56). In a third experiment with R. reniformis (IP = 1800) that included the same cultivars as in Experiment I, all cultivars were rated as resistant (RF means ranged from 0.01 to 0.29).

Genome wide scan for quantitative trait loci affecting tick resistance in cattle (Bos taurus x Bos indicus)

Background : In tropical countries, losses caused by bovine tick Rhipicephalus (Boophilus) microplus infestation have a tremendous economic impact on cattle production systems. Genetic variation between Bos taurus and Bos indicus to tick resistance and molecular biology tools might allow for the identification of molecular markers linked to resistance traits that could be used as an auxiliary tool in selection programs. The objective of this work was to identify QTL associated with tick resistance/susceptibility in a bovine F2 population derived from the Gyr (Bos indicus) x Holstein (Bos taurus) cross. Results: Through a whole genome scan with microsatellite markers, we were able to map six genomic regions associated with bovine tick resistance. For most QTL, we have found that depending on the tick evaluation season (dry and rainy) different sets of genes could be involved in the resistance mechanism. We identified dry season specific QTL on BTA 2 and 10, rainy season specific QTL on BTA 5, 11 and 27. We also found a highly significant genome wide QTL for both dry and rainy seasons in the central region of BTA 23. Conclusions: The experimental F2 population derived from Gyr x Holstein cross successfully allowed the identification of six highly significant QTL associated with tick resistance in cattle. QTL located on BTA 23 might be related with the bovine histocompatibility complex. Further investigation of these QTL will help to isolate candidate genes involved with tick resistance in cattle.

Effects of enriched colostrum supply in intestinal mucosa morphology of newborn calves

Colostrum intake in neonatal calves is essential to obtain passive immunity and to influence metabolism, endocrine systems and the nutritional state. This study compares morphologic features of small intestine of calves fed a colostrum second meal at 12 hours of life with concentrations of immunoglobulin G (IgG) higher than 100mg mL(-1) (fresh colostrum or artificially prepared with addition of lyophilized colostrum) or smaller than 30mg mL(-1). Twenty-four Holstein calves were randomly grouped according to concentration of IgG intake at 12 hours of life: low (less than 30mg mL(-1)); high (more than 100mg mL(-1)); plus lyophilized colostrum (more than 120mg mL(-1)). Intestinal tissue samples were collected at 0, 10, 24 and 72 hours after birth to evaluate morphology in segments: duodenum; proximal, middle and distal jejunum and ileum by examined with a scanning electron microscope. Villi of all segments showed more organized and uniform morphology characteristics with age. Only the animals fed colostrum with more than 100mg mL(-1) of IgG at 24 hours after birth still showed the distal jejunum villi disoriented and more united in comparison to the other ages and groups. Intake of lyophilized colostrum affected ileum morphology along experiment period. Higher concentration of immunologic and bioactive elements supplied for longer period of time could be responsible for promoting effects on the enterocytes. Use of colostrum with high IgG concentrations, with or without addition of lyophilized colostrum, influenced the precocity of the intestinal mucosa development in newborn calves, suggesting earlier maturation of the mucosa.

Coleópteros coletados com armadilhas luminosas e etanólicas em plantio de Eucalyptus spp. no sul do Rio Grande do Sul

The objective of this study was to collect, identify and study population fluctuation of Coleoptera species in a forest of Eucalyptus spp., on a farm in the municipality of Pinheiro Machado, Rio Grande do Sul State. Insects were collected with light traps and ethanol traps, once every fifteen days, in the period of February 2006 to October 2007. The insects, after selection procedures, were identified based on entomological collections and specialized literature. A total of 6172 individuals were collected and distributed among 40 families and 249 species, of which 130 were identified at the species level and 119 at the family level, representing 4498 and 1674 of total individuals collected, respectively. Cyclocephala sp. 1, Cyclocephala sp. 2, Dyscinetus sp. 1, Euetheola humilis (Scarabaeidae) and Neoclytus curvatus (Cerambycidae) were the most abundant species, representing 49.28% of the individuals identified in genus and/or species. Scarabaeidae presented the highest number of individuals (2588), distributed in 37 species. The families Cerambycidae (47) and Scolytidae (40) presented the largest number of species. Individuals of Coleoptera were trapped at all collections but the largest number of individuals was trapped in December 2006 and March 2007.

Identification of a Highly Antigenic Linear B Cell Epitope within Plasmodium vivax Apical Membrane Antigen 1 (AMA-1)

Apical membrane antigen 1 (AMA-1) is considered to be a major candidate antigen for a malaria vaccine. Previous immunoepidemiological studies of naturally acquired immunity to Plasmodium vivax AMA-1 (PvAMA-1) have shown a higher prevalence of specific antibodies to domain II (DII) of AMA-1. In the present study, we confirmed that specific antibody responses from naturally infected individuals were highly reactive to both full-length AMA-1 and DII. Also, we demonstrated a strong association between AMA-1 and DII IgG and IgG subclass responses. We analyzed the primary sequence of PvAMA-1 for B cell linear epitopes co-occurring with intrinsically unstructured/ disordered regions (IURs). The B cell epitope comprising the amino acid sequence 290-307 of PvAMA-1 (SASDQPTQYEEEMTDYQK), with the highest prediction scores, was identified in domain II and further selected for chemical synthesis and immunological testing. The antigenicity of the synthetic peptide was identified by serological analysis using sera from P. vivax-infected individuals who were knowingly reactive to the PvAMA-1 ectodomain only, domain II only, or reactive to both antigens. Although the synthetic peptide was recognized by all serum samples specific to domain II, serum with reactivity only to the full-length protein presented 58.3% positivity. Moreover, IgG reactivity against PvAMA-1 and domain II after depletion of specific synthetic peptide antibodies was reduced by 18% and 33% (P = 0.0001 for both), respectively. These results suggest that the linear epitope SASDQPTQYEEEMTDYQK is highly antigenic during natural human infections and is an important antigenic region of the domain II of PvAMA-1, suggesting its possible future use in pre-clinical studies.

Plasmodium vivax circumsporozoite genotypes: a limited variation or new subspecies with major biological consequences?

Background: Plasmodium vivax circumsporozoite variants have been identified in several geographical areas. The real implication of the genetic variation in this region of the P. vivax genome has been questioned for a long time. Although previous studies have observed significant association between VK210 and the Duffy blood group, we present here that evidences of this variation are limited to the CSP central portion. Methods: The phylogenetic analyses were accomplished starting from the amplification of conserved domains of 18 SSU RNAr and Cyt B. The antibodies responses against the CSP peptides, MSP-1, AMA-1 and DBP were detected by ELISA, in plasma samples of individuals infected with two P. vivax CS genotypes: VK210 and P. vivax-like. Results: These analyses of the two markers demonstrate high similarity among the P. vivax CS genotypes and surprisingly showed diversity equal to zero between VK210 and P. vivax-like, positioning these CS genotypes in the same clade. A high frequency IgG antibody against the N- and C-terminal regions of the P. vivax CSP was found as compared to the immune response to the R- and V-repetitive regions (p = 0.0005, Fisher's Exact test). This difference was more pronounced when the P. vivax-like variant was present in the infection (p = 0.003, Fisher's Exact test). A high frequency of antibody response against MSP-1 and AMA-1 peptides was observed for all P. vivax CS genotypes in comparison to the same frequency for DBP. Conclusions: This results target that the differences among the P. vivax CS variants are restrict to the central repeated region of the protein, mostly nucleotide variation with important serological consequences.

Brazilian foreign policy: Old and new paths as regards institutional aspects, multilateralism and foreign policy towards the South

This paper emphasizes the important changes in Brazilian foreign policy after Luiz Inacio Lula da Silva took tip the power in 2002. The paper defends the idea that it is not possible to argue that there were deep changes in comparison to Cardoso's administration. However, evidence shows that new things are happening as regards the design of a more active and clear foreign action line which led to institutional changes and to more incisive multilateral paths. This results both from the political profile of the direct operators of foreign policy and the aims of lite presidential diplomacy, The hypothesis dealt with on this paper consists on the fact that Lula's administration has not fully broken with the old administration practices, however the aims of global and regional integration are being plotted more clearly and with a higher degree of activism. This becomes clear in three aspects of the Brazilian foreign policy: the institutional framework, the practice of multilateralism and the foreign policy towards the South, the three topics analyzed in this paper.

Robotic Resection of Intraductal Neoplasm of the Pancreas

Background: Minimally invasive techniques have been revolutionary and provide clinical evidence of decreased morbidity and comparable efficacy to traditional open surgery. Computer-assisted surgical devices have recently been approved for general surgical use. Aim: The aim of this study was to report the first known case of pancreatic resection with the use of a computer-assisted, or robotic, surgical device in Latin America. Patient and Methods: A 37-year-old female with a previous history of radical mastectomy for bilateral breast cancer due to a BRCA2 mutation presented with an acute pancreatitis episode. Radiologic investigation disclosed an intraductal pancreatic neoplasm located in the neck of the pancreas with atrophy of the body and tail. The main pancreatic duct was enlarged. The surgical decision was to perform a laparoscopic subtotal pancreatectomy, using the da Vinci (R) robotic system (Intuitive Surgical, Sunnyvale, CA). Five trocars were used. Pancreatic transection was achieved with vascular endoscopic stapler. The surgical specimen was removed without an additional incision. Results: Operative time was 240 minutes. Blood loss was minimal, and the patient did not receive a transfusion. The recovery was uneventful, and the patient was discharged on postoperative day 4. Conclusions: The subtotal laparoscopic pancreatic resection can safely be performed. The da Vinci robotic system allowed for technical refinements of laparoscopic pancreatic resection. Robotic assistance improved the dissection and control of major blood vessels due to three-dimensional visualization of the operative field and instruments with wrist-type end-effectors.