Initial contact and toe off event identification for rearfoot and non-rearfoot strike pattern treadmill running at different speeds

The purpose of this study was to determine the validity of kinematic based initial contact (IC) and toe-off (TO) identification algorithms for rearfoot and non-rearfoot runners across a broad range of treadmill running speeds. 14 healthy active participants completed six 20–60 s treadmill running trials at 6 speeds: 2.24, 2.68, 3.13, 3.58, 4.02, and 4.48 ms⁻¹. 3D kinematic data were collected for the last 20 s of each trial. Force plates (FP) were used as the gold standard to determine ICFP and TOFP for each step. Three algorithms for finding IC, IC_Milner, IC_Alvim, IC_Alvim-mod, and one algorithm for finding toe off, TO_Fellin, were chosen for analysis. Root mean square errors (RMSE) and difference scores with 95% confidence intervals were computed for IC, TO and stance time (ST). IC_Alvim RMSE ranged from 0.175 to 0.219 s. ST_Alvim RMSE ranged from 0.168 to 0.216 s. IC_Alvim-mod RMSE ranged from 0.105 to 0.131 s. ST_Alvim-mod RMSE ranged from 0.108 to 0.129 s. IC_Milner RMSE ranged 0.012 to 0.015 s. ST_Milner RMSE ranged 0.019 to 0.024 s. IC_Milner accuracy was inversely related to speed. IC_Milner corrected with a linear regression equation reduced differences to- 0.006 ± 0.012 s with 86% of foot strikes identified within 20 ms and 58% with 10 ms. TO_Fellin RMSE ranged from 0.012 to 0.016 s. IC_Milner adjusted for speed and TO_Fellin can be used to predict IC and TO within a broad range of treadmill running speeds (2.24–4.48 ms⁻¹) and for rearfoot and non-rearfoot strikers.     

Sclerochronological study of the gigantic inoceramids Sphenoceramus schmidti and S. sachalinensis from Hokkaido,northern Japan

Here, we present the first sclerochronological investigation of shells of the gigantic inoceramids Sphenoceramus schmidti and S. sachalinensis from the middle Campanian cold seep carbonate‐bearing strata of the Yezo Basin in Hokkaido (northern Japan). Stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotope values were measured in the aragonitic and calcitic shell layers of both species and compared to those of other co‐occurring benthic (mainly bivalves and gastropods) and demersal molluscs (ammonites). Sedimentological and stable isotope data suggest that these bivalves lived near cold seeps and were exposed to high H₂S level in the seawater. The inoceramid shells exhibited higher δ¹³C and lower δ¹⁸O values than the coeval non‐cold seep molluscs. We ascribed the anomalous isotopic pattern to a combination of vital and environmental effects determined by the hosting of chemosymbionts and the exposure to warm interstitial waters. Inoceramid δ¹³C minima coincided with growth lines and likely reflect changes in nutrient supply by the chemosymbionts. Absolute temperatures estimated from δ¹⁸O values of Sphenoceramus schmidti and S. sachalinensis were, on average, ca. 4–5°C warmer than those reconstructed for the non‐seepage environment (19.3 ± 0.7°C). Short‐term δ¹⁸O fluctuations of the inoceramid material indicate local temperature ranges of up to 5.2°C, that is four times larger than those reconstructed from the benthic and demersal fauna (1.3°C). In general, our data suggest that the stable carbon and oxygen isotope values of the studied Sphenoceramus spp. were strongly affected by short‐term fluctuations in seepage activity and do not reflect seasonal fluctuations.     

External water transport is more important than vascular transport in the extreme atmospheric epiphyte Tillandsia usneoides (Spanish moss)

Most epiphytic bromeliads, especially those in the genus Tillandsia, lack functional roots and rely on the absorption of water and nutrients by large, multicellular trichomes on the epidermal surfaces of leaves and stems. Another important function of these structures is the spread of water over the epidermal surface by capillary action between trichome “wings” and epidermal surface. Although critical for the ultimate absorption by these plants, understanding of this function of trichomes is primarily based on light microscope observations. To better understand this phenomenon, the distribution of water was followed by its attenuation of cold neutrons following application of H₂O to the cut end of Tillandsia usneoides shoots. Experiments confirmed the spread of added water on the external surfaces of this “atmospheric” epiphyte. In a morphologically and physiologically similar plant lacking epidermal trichomes, water added to the cut end of a shoot clearly moved via its internal xylem and not on its epidermis. Thus, in T. usneoides, water moves primarily by capillarity among the overlapping trichomes forming a dense indumentum on shoot surfaces, while internal vascular water movement is less likely. T. usneoides, occupying xeric microhabitats, benefits from reduction of water losses by low‐shoot xylem hydraulic conductivities.     

Genetic diversity of Colletotrichum gloeosporioides species complex associated with Citrus wither‐tip of twigs in Tunisia using microsatellite markers

Anthracnose Citrus disease has been associated with several symptoms worldwide and it is recently compromising Citrus production in the Mediterranean area. Four species complexes are mainly involved: Colletotrichum boninense, C. acutatum, C. gloeosporioides and C. truncatum. In this study, we investigated the genetic diversity of Colletotrichum spp. in Tunisia associated with wither‐tip of twigs on Citrus. Specific primers ITS4‐CgInt allowed the identification of C. gloeosporioides species complex in all the 54 isolates, sampled from three regions and four Citrus species. Overall, our genotypic analysis using 10 SSR markers showed a moderate diversity level in Tunisian C. gloeosporioides population and highlighted that C. gloeosporioides reproduce mainly clonally. In addition, heterothallic isolates were present in our population, suggesting that the pathogen population may undergo parasexual recombinations. The highest genetic diversity in C. gloeosporioides was recorded in Nabeul and on orange, which likely constitutes the area and the host of origin for the Citrus anthracnose disease in Tunisia. In addition, no population subdivision was detected at the geographic, host species or cultivars’ origin levels. However, our study identified two genetic subpopulations and indicated a rapid C. gloeosporioides population change at temporal scale that should be further examined over several consecutive growing seasons in order to understand its population dynamics.     

Modelling time‐varying low‐temperature‐induced mortality rates for pupae of Tuta absoluta (Gelechiidae,Lepidoptera)

In a series of laboratory experiments, acclimated pupae of Tuta absoluta were exposed to various constant low temperatures in order to estimate their maximum survival times (Kaplan–Meier, Lt_99.99). A Weibull function was fitted to the data points, describing maximum survival time as a function of temperature. In another experiment at ?6°C, the progress of mortality increasing with exposure time was identified. These values were fitted by a sigmoidal function converging asymptotically to 100% mortality for very long exposure times. Analysing mortality data from the maximum survival experiment by a generalized linear model showed a significant common slope parameter (p < .001) that reveals parallelism of the survival curves at each temperature if a log time axis is used. These curves appear stretched (time scaled) if plotted with a nonlogarithmic time axis. By combining these mathematical relations, it was possible to calculate a species‐specific ‘mortality surface’ which exhibits mortalities, depending on temperature and duration of exposure. In order to accumulate hourly mortalities for courses of varying temperatures, an algorithm was developed which yields mortality values from that surface taking into account the attained mortality level. In validation experiments, recorded mortalities were compared against modelled mortalities. Prediction of mortality was partially supported by the model, but pupae experiencing intensely fluctuating temperatures showed decreased mortality, probably caused by rapid cold hardening during exposure. Despite this observation, mortality data converged to distinct levels very close to 100% depending on the intensity of temperature fluctuations that were characteristic for different types of experiments. The highest mortality limit occurred at intensely fluctuating temperatures in laboratory experiments. This constituted a benchmark that was not reached under various field conditions. Thus, it was possible to identify temperature limits for the extinction of field populations of Tuta absoluta pupae.     

Genetic information improves the prediction of major adverse cardiovascular events in the GENEMACOR population

The inclusion of a genetic risk score (GRS) can modify the risk prediction of coronary artery disease (CAD), providing an advantage over the use of traditional models. The predictive value of the genetic information on the recurrence of major adverse cardiovascular events (MACE) remains controversial. A total of 33 genetic variants previously associated with CAD were genotyped in 1587 CAD patients from the GENEMACOR study. Of these, 18 variants presented an hazard ratio >1, so they were selected to construct a weighted GRS (wGRS). MACE discrimination and reclassification were evaluated by C-Statistic, Net Reclassification Index and Integrated Discrimination Improvement methodologies. After the addition of wGRS to traditional predictors, the C-index increased from 0.566 to 0.572 (p=0.0003). Subsequently, adding wGRS to traditional plus clinical risk factors, this model slightly improved from 0.620 to 0.622 but with statistical significance (p=0.004). NRI showed that 17.9% of the cohort was better reclassified when the primary model was associated with wGRS. The Kaplan-Meier estimator showed that, at 15-year follow-up, the group with a higher number of risk alleles had a significantly higher MACE occurrence (p=0.011). In CAD patients, wGRS improved MACE risk prediction, discrimination and reclassification over the conventional factors, providing better cost-effective therapeutic strategies.     

High expression level of a gene coding for a chloroplastic amino acid selective channel protein is correlated to cold acclimation in cereals

A cold-regulated gene (cor tmc-ap3) coding for a putative chloroplastic amino acid selective channel protein was isolated from cold-treated barley leaves combining the differential display and the 5-RACE techniques. Cor tmc-ap3 is expressed at low level under normal growing temperature, and its expression is strongly enhanced after cold treatment. A positive correlation between the expression of cor tmc-ap3 and frost tolerance was found both among barley cultivars and among cereal species. The COR TMC-AP3 protein was expressed in vitro, purified and used to raise a polyclonal antibody. Western analysis showed that the cor tmc-ap3 gene product is localized to the chloroplastic outer envelope fraction, supporting its putative function. The frost-resistant winter cultivar Onice accumulated COR TMC-AP3 more rapidly and at a higher level than the frost-susceptible spring cultivar Gitane. After 28 days of cold acclimation the winter cultivar had about 2-fold more protein than the spring genotype. All these results suggest that an increased amount of a chloroplastic amino acid selective channel protein could be required for cold acclimation in cereals. Hypotheses about the role of COR TMC-AP3 during the hardening process are discussed.     

An electrostatic basis for the stability of thermophilic proteins

Two factors provide key contributions to the stability of thermophilic proteins relative to their mesophilic homologues: electrostatic interactions of charged residues in the folded state and the dielectric response of the folded protein. The dielectric response for proteins in a "thermophilic series" globally modulates the thermal stability of its members, with the calculated dielectric constant for the protein increasing from mesophiles to hyperthermophiles. This variability results from differences in the distribution of charged residues on the surface of the protein, in agreement with structural and genetic observations. Furthermore, the contribution of electrostatic interactions to the stability of the folded state is more favorable for thermophilic proteins than for their mesophilic homologues. This leads to the conclusion that electrostatic interactions play an important role in determining the stability of proteins at high temperatures. The interplay between electrostatic interactions and dielectric response also provides further rationalization for the enhanced stability of thermophilic proteins with respect to cold-denaturation. Taken together, the distribution of charged residues and their fluctuations have been shown to be factors in modulating protein stability over the entire range of biologically relevant temperatures.