Validity and reliability of strategy metrics to assess countermovement jump performance using the newly developed My Jump Lab smartphone application

The aim of the present study was to analyse the validity and reliability of the newly developed My Jump Lab smartphone app, which includes the option to calculate time to take-off and the reactive strength index modified (RSI_Mod – calculated as jump height divided by time to take-off), in addition to jump height. Twenty-seven postgraduate sport science students attended a single test session and performed three maximal effort countermovement jumps (CMJ) on twin force plates, whilst concurrently being filmed using the app. Results showed no significant differences in jump height between measurement methods (g = 0.00) or RSI_Mod (g = -0.49), although a significant difference was evident for time to take-off (g = 0.68). When a correction factor was applied to time to take-off data, no meaningful differences were evident (g = 0.00), which also had a knock-on effect for RSI_Mod (g = 0.10). Bland-Altman analysis showed near perfect levels of agreement for jump height with a bias estimate of 0.001 m, whilst time to take-off reported a bias estimate of 0.075 s initially and, 0.000 s once the correction factor was applied. For RSI_Mod, bias estimate was initially -0.048, and 0.006 once calculated with the corrected time to take-off data. Pearson’s r correlations were: 0.98 for jump height, 0.81 for time to take-off, and 0.85 for RSI_Mod. Based on the findings from the present study, and with the inclusion of the newly embedded correction factor, My Jump Lab can now be used as both a valid and reliable means of measuring time to take-off and RSI_Mod in the CMJ

Jump and change of direction speed asymmetry using smartphone apps: between-session consistency and associations with physical performance

The aims of the present study were to: 1) quantify the magnitude and direction of asymmetry from jump and change of direction speed (CODS) tests and, 2) determine the relationship between these asymmetries and jump and CODS performance, in a test-retest design. Thirty Spanish national level youth basketball athletes performed single leg countermovement jumps (SLCMJ), single leg drop jumps (SLDJ), and 505 CODS tests, all assessed using the My Jump 2™ and CODTimer™ smartphone applications. All tests showed good to excellent reliability, with no significant differences identified between test sessions in jump, CODS, or asymmetry data. The direction of asymmetry showed substantial levels of agreement between test sessions for jump height during the SLDJ (Kappa = 0.72), but only fair levels of agreement for reactive strength during the SLDJ (Kappa = 0.25), fair levels of agreement for jump height during the SLCMJ (Kappa = 0.29), and slight levels of agreement for total time during the 505 test (Kappa = 0.18). Jump height asymmetry from the SLDJ was significantly associated with reduced jump height (ρ = -0.44), reactive strength (ρ = -0.46) and 505 times (ρ = 0.45-0.48) in test session 1, and reactive strength (ρ = -0.42) and 505 time (ρ = 0.40) in test session 2. These data show that jump height asymmetry from the SLDJ was associated with reduced jump and CODS performance in youth basketball athletes during repeated test sessions. In addition, the same asymmetry metric was the only one to show substantial levels of agreement between test sessions. Owing to the consistency of these data, SLDJ height asymmetry may be a useful metric to measure when monitoring inter-limb asymmetries

The validity and reliability of a novel app for the measurement of change of direction performance

The aim of the present investigation was to analyze the validity and reliability of a novel iPhone app (CODTimer) for the measurement of total time and interlimb asymmetry in the 5 + 5 change of direction test (COD). To do so, twenty physically active adolescent athletes (age = 13.85 ± 1.34 years) performed six repetitions in the COD test while being measured with a pair of timing gates and CODTimer. A total of 120 COD times measured both with the timing gates and the app were then compared for validity and reliability purposes. There was an almost perfect correlation between the timing gates and the CODTimer app for the measurement of total time (r = 0.964; 95% Confidence interval (CI) = 0.95-1.00; Standard error of the estimate = 0.03 s.; p  0.05). Similar levels of reliability were observed between the timing gates and the app for the measurement of the 6 different trials of each participant (Timing gates: Intraclass correlation coefficient (ICC) = 0.651-0.747, Coefficient of variation (CV) = 2.6-3.5%; CODTimer: ICC = 0.671-0.840, CV = 2.2-3.2%). The results of the present study show that change of direction performance can be measured in a valid, reliable way using a novel iPhone app

Digestibilidade de gerações de perfilhos do capim Tanzânia.

O objetivo do presente experimento foi determinar o efeito da intensidade e do ciclo de pastejo sobre a digestibilidade in vitro da matéria orgânica de gerações de perfilhos de capim Tanzânia. O delineamento experimental foi de blocos completos ao acaso com três tratamentos (intensidade de pastejo alta, média e baixa) e quatro repetições. As gerações de perfilhos eram identificadas com fios de arame coloridos. Um dia antes de cada pastejo duas amostras eram cortadas por parcela e a digestibilidade in vitro da matéria orgânica de cada geração determinada. A digestibilidade das gerações de perfilhos foi maior nas áreas submetidas a elevada intensidade de pastejo e decresceu com o avanço da idade (redução de 3 a 6 pontos percentuais de digestibilidade por ciclo) .Os efeitos negativos do florescimento sobre o valor nutritivo da forragem podem ser reduzidos através de práticas de manejo que promovam uma maior renovação de perfilhos

Antibiotics Shaping Bacterial Genome: Deletion of an IS91 Flanked Virulence Determinant upon Exposure to Subinhibitory Antibiotic Concentrations

The nucleoid-associated proteins Hha and YdgT repress the expression of the toxin α-hemolysin. An Escherichia coli mutant lacking these proteins overexpresses the toxin α-hemolysin encoded in the multicopy recombinant plasmid pANN202-312R. Unexpectedly, we could observe that this mutant generated clones that no further produced hemolysin (Hly-). Generation of Hly- clones was dependent upon the presence in the culture medium of the antibiotic kanamycin (km), a marker of the hha allele (hha::Tn5). Detailed analysis of different Hly- clones evidenced that recombination between partial IS91 sequences that flank the hly operon had occurred. A fluctuation test evidenced that the presence of km in the culture medium was underlying the generation of these clones. A decrease of the km concentration from 25 mg/l to 12.5 mg/l abolished the appearance of Hly- derivatives. We considered as a working hypothesis that, when producing high levels of the toxin (combination of the hha ydgT mutations with the presence of the multicopy hemolytic plasmid pANN202-312R), the concentration of km of 25 mg/l resulted subinhibitory and stimulated the recombination between adjacent IS91 flanking sequences. To further test this hypothesis, we analyzed the effect of subinhibitory km concentrations in the wild type E. coli strain MG1655 harboring the parental low copy number plasmid pHly152. At a km concentration of 5 mg/l, subinhibitory for strain MG1655 (pHly152), generation of Hly- clones could be readily detected. Similar results were also obtained when, instead of km, ampicillin was used. IS91 is flanking several virulence determinants in different enteric bacterial pathogenic strains from E. coli and Shigella. The results presented here evidence that stress generated by exposure to subinhibitory antibiotic concentrations may result in rearrangements of the bacterial genome. Whereas some of these rearrangements may be deleterious, others may generate genotypes with increased virulence, which may resume infection

Controle genético da resistência a murcha-de-fusário em feijoeiro comum.

Os objetivos do trabalho foram avaliar o controle genético da reação ao agente causal da murcha-de-fusário, a partir dos cruzamentos Milionário 1732 x Macanudo e FT Tarumã x Macanudo, e estimar parâmetros genéticos que permitam selecionar famílias resistentes à doença

Loss-of-function mutations in the CABLES1 gene are a novel cause of Cushing's disease.

The CABLES1 cell cycle regulator participates in the adrenal-pituitary negative feedback, and its expression is reduced in corticotropinomas, pituitary tumors with a largely unexplained genetic basis. We investigated the presence of CABLES1 mutations/copy number variations (CNVs) and their associated clinical, histopathological and molecular features in patients with Cushing's disease (CD). Samples from 146 pediatric (118 germline DNA only/28 germline and tumor DNA) and 35 adult (tumor DNA) CD patients were screened for CABLES1 mutations. CNVs were assessed in 116 pediatric CD patients (87 germline DNA only/29 germline and tumor DNA). Four potentially pathogenic missense variants in CABLES1 were identified, two in young adults (c.532G > A, p.E178K and c.718C > T, p.L240F) and two in children (c.935G > A, p.G312D and c.1388A > G, and p.D463G) with CD; no CNVs were found. The four variants affected residues within or close to the predicted cyclin-dependent kinase-3 (CDK3)-binding region of the CABLES1 protein and impaired its ability to block cell growth in a mouse corticotropinoma cell line (AtT20/D16v-F2). The four patients had macroadenomas. We provide evidence for a role of CABLES1 as a novel pituitary tumor-predisposing gene. Its function might link two of the main molecular mechanisms altered in corticotropinomas: the cyclin-dependent kinase/cyclin group of cell cycle regulators and the epidermal growth factor receptor signaling pathway. Further studies are needed to assess the prevalence of CABLES1 mutations among patients with other types of pituitary adenomas and to elucidate the pituitary-specific functions of this gene

Population structure, antimicrobial resistance and virulence-associated genes in Campylobacter jejuni isolated from three ecological niches: gastroenteritis patients, broilers, and wild birds

Campylobacter jejuni is the causal agent of the food-borne infection with the highest incidence in Europe. Both poultry and wild birds are a major reservoir. To gain insight into the population structure, virulence potential, and antimicrobial resistance (AMR), a collection of 150 isolates from three different ecological niches (broilers, wild birds, and human patients) was studied. Despite the high genetic diversity found, the population structure defined two distinct clusters, one formed mostly by broiler and human isolates and another one by most wild bird isolates. The ST-21 complex exhibits highest prevalence (in humans and broilers), followed by ST-1275 complex (only in wild birds). The ST-48, -45, and -354 complexes were found in all three niches, but represent only 22 out of 150 studied strains. A higher occurrence of AMR and multidrug resistance was detected among broiler and human isolates. Moreover, significant differences were found in the distribution of certain putative virulence genes. Remarkably, many wild bird strains were negative for either cdtA, cdtB, or cdtC from the canonical strain 81-176, whereas all broiler and human strains were positive. These data suggest that the different variants of the cdt genes might be relevant for the efficient colonization of certain hosts by C. jejuni. Our study contributes to the understanding of the role of the diverse Campylobacter reservoirs in the transmission of campylobacteriosis to humans

Mapeamento genético da resistência a murcha do fusario em feijoeiro comum.

Este trabalho objetivou identificar marcadores microssatélites ligados a genes de resistência a Fusarium oxysporum f. sp. phaseoli em feijoeiro comum