Linear and Nonlinear Measures Predict Swimming in the Leech

Stimulation of a trigger interneuron of an isolated nerve cord preparation of the medicinal leech, Hirudo medicinalis, sometimes leads to swimming; sometimes it does not. We investigate signals transmitted in the ventral cord of the leech after stimulation and seek quantitative measures that would make it possible to distinguish signals that predict swimming from those that do not. We find that a number of linear as well as nonlinear measures provide statistically significant distinctions between the two kinds of signals. The linear measures are the time dependence of (i) the standard deviation and (ii) the autocorrelation function at a small time delay. The nonlinear measures are (i) a measure of nonlinear predictability and (ii) the time dependence of a measure of the size of the embedded signal trajectory. Calculations using surrogate data suggest that the differences between the two classes of signals are dynamical as well as statistical

Linear and Nonlinear Measures Predict Swimming in the Leech

Stimulation of a trigger interneuron of an isolated nerve cord preparation of the medicinal leech, Hirudo medicinalis, sometimes leads to swimming; sometimes it does not. We investigate signals transmitted in the ventral cord of the leech after stimulation and seek quantitative measures that would make it possible to distinguish signals that predict swimming from those that do not. We find that a number of linear as well as nonlinear measures provide statistically significant distinctions between the two kinds of signals. The linear measures are the time dependence of (i) the standard deviation and (ii) the autocorrelation function at a small time delay. The nonlinear measures are (i) a measure of nonlinear predictability and (ii) the time dependence of a measure of the size of the embedded signal trajectory. Calculations using surrogate data suggest that the differences between the two classes of signals are dynamical as well as statistical

MASH TL-3 Evaluation of TxDOT Extra-Large Mailboxes

0-6968The purpose of the testing reported herein was to assess the performance of Texas Department of Transportation's (TxDOT\u2019s) extra-large mailboxes according to the safety-performance evaluation guidelines included in the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) for Test Level Three (TL-3) for support structures. The mailboxes tested were the single extra-large mailbox on Type 4 support, two architectural mailboxes and two medium mailboxes on a bent pipe support, and a single extra-large mailbox on Type 3 support. The single Centennial model #950020B extra-large mailbox on Type 4 support performed acceptably for MASH Test 3-61. The multiple mailboxes on a bent pipe support also showed the installation to performed acceptably for MASH Test 3-61. The windshield of the test vehicle deformed 4.6 inches into the occupant compartment and the laminate was torn during MASH Test 3-61 on the single Centennial model #950020B extra-large mailbox on Type 3 support. The installation failed criterion D of MASH. In a re-test after applying a modification to the connection bracket of the single Centennial model #950020B extra-large mailbox, the Type 3 support performed acceptably for MASH Test 3-61

Feasibility and effects of adapted cardiac rehabilitation after stroke: a prospective trial

Abstract Background Despite the cardiovascular etiology of stroke, exercise and risk factor modification programs akin to cardiac rehabilitation (CR) are not available. This study aimed to establish the feasibility of adapting a CR model for individuals with mild to moderate stroke disability. A secondary objective was to determine the program's effects on aerobic and walking capacity, and stroke risk factors. Methods A repeated measures design was used with a 3-month baseline period and 6-month adapted CR intervention (n = 43, mean ± SD age 65 ± 12 years, 30 ± 28 months post stroke). Feasibility was determined by the number of participants who completed the study, occurrence of adverse events and frequency, duration and intensity of exercise performed. To determine effectiveness of the program, outcomes measured included aerobic capacity (VO2peak, ventilatory threshold), 6-Minute Walk Test (6MWT) distance, and risk factors. Descriptive statistics characterized the classes attended and number and intensity of exercise sessions. Paired t-tests, one-factor repeated measures analyses of variance contrasts and chi-square analyses were used to compare changes over time. Results Two participants withdrew during the baseline period. Of the remaining 41 participants who commenced the program, 38 (93%) completed all aspects. No serious adverse effects occurred. Post-intervention, VO2peak improved relative to the stable baseline period (P = 0.046) and the increase in ventilatory threshold approached significance (P = 0.062). Conclusions CR is feasible after stroke and may be adapted to accommodate for those with a range of post-stroke disability. It is effective in increasing aerobic capacity. CR may be an untapped opportunity for stroke survivors to access programs of exercise and risk factor modification to lower future event risk. Trial registration ClinicalTrials.gov registration number: NCT0106749

Exploring Cell Tropism as a Possible Contributor to Influenza Infection Severity

Several mechanisms have been proposed to account for the marked increase in severity of human infections with avian compared to human influenza strains, including increased cytokine expression, poor immune response, and differences in target cell receptor affinity. Here, the potential effect of target cell tropism on disease severity is studied using a mathematical model for in-host influenza viral infection in a cell population consisting of two different cell types. The two cell types differ only in their susceptibility to infection and rate of virus production. We show the existence of a parameter regime which is characterized by high viral loads sustained long after the onset of infection. This finding suggests that differences in cell tropism between influenza strains could be sufficient to cause significant differences in viral titer profiles, similar to those observed in infections with certain strains of influenza A virus. The two target cell mathematical model offers good agreement with experimental data from severe influenza infections, as does the usual, single target cell model albeit with biologically unrealistic parameters. Both models predict that while neuraminidase inhibitors and adamantanes are only effective when administered early to treat an uncomplicated seasonal infection, they can be effective against more severe influenza infections even when administered late

Tree growing space and acorn production of Quercus robur

Pedunculate oak (Quercus robur L.) is considered the main commercial tree species in conditions of floodplain forests of central Europe. In the Czech Republic clear-cutting silvicultural system represents a prevailing regeneration method of oak stands in floodplain forest. The natural regeneration is limited only in stands and years with sufficient acorn production. We analysed an acorn crop periodicity and an influence of canopy opening to the acorn production in South Moravian floodplain forest, Czech Republic between 2008 and 2011, The acorn crop from trees with different growth spaces in four stand conditions (closed canopy (A), moderate open canopy (B), open canopy (C) and single growing trees (D) with unlimited growth space was analysed. The amount of acorns was determined using seed traps placed under the crowns of sample trees. The average amount of acorns in 2009 and 2011 ranged from 13 (A) to 102 (C)/m2 and from 2 (A) to 124 (D)/m2, respectively. At the same time, a considerable difference was recorded in the fructification of sample trees in the various stand situations. Significant correlations were confirmed between the amount of acorns and crown size (r2 2009=0.27, r2 2011=0.07) of parent trees and their growth space – release area (r2 2009=0.42, r2 2011=0.25) and social area (r2 2009=0.31, r2 2011=0.26). The production of acorns could be affected by establishing conditions for the pedunculate oak with a minimum crown projection area in adult trees of at least 70 m2 and/or with a minimum release area of 300 m2, it means spacing between parent trees about 10 m or 100 trees per 1 ha