Topological partition relations to the form omega^*-> (Y)^1_2

Theorem: The topological partition relation omega^{*}-> (Y)^{1}_{2} (a) fails for every space Y with |Y| >= 2^c ; (b) holds for Y discrete if and only if |Y| <= c; (c) holds for certain non-discrete P-spaces Y ; (d) fails for Y= omega cup {p} with p in omega^{*} ; (e) fails for Y infinite and countably compact

Comparison of bone healing in four types of jaw cysts

Abstract no. 1019published_or_final_versio

Precompact noncompact reflexive abelian groups

We present a series of examples of precompact, noncompact, reflexive topological Abelian groups. Some of them are pseudocompact or even countably compact, but we show that there exist precompact non-pseudocompact reflexive groups as well. It is also proved that every pseudocompact Abelian group is a quotient of a reflexive pseudocompact group with respect to a closed reflexive pseudocompact subgroup

Sex differences in countermovement jump phase characteristics

The countermovement jump (CMJ) is commonly used to explore sex differences in neuromuscular function, but previous studies have only reported gross CMJ measures or have partly examined CMJ phase characteristics. The purpose of this study was to explore differences in CMJ phase characteristics between male and female athletes by comparing the force-, power-, velocity-, and displacement-time curves throughout the entire CMJ, in addition to gross measures. Fourteen men and fourteen women performed three CMJs on a force platform from which a range of kinetic and kinematic variables were calculated via forward dynamics. Jump height (JH), reactive strength index modified, relative peak concentric power, and eccentric and concentric displacement, velocity, and relative impulse were all greater for men (g = 0.58–1.79). Relative force-time curves were similar between sexes, but relative power-, velocity-, and displacement-time curves were greater for men at 90%–95% (immediately before and after peak power), 47%–54% (start of eccentric phase) and 85%–100% (latter half of concentric phase), and 65%–87% (bottom of countermovement and initial concentric phase) of normalized jump time, respectively. The CMJ distinguished between sexes, with men demonstrating greater JH through applying a larger concentric impulse and, thus, achieving greater velocity throughout most of the concentric phase, including take-off

Effect of onset threshold on kinetic and kinematic variables of a weightlifting derivative containing a first and second pull

This study sought to determine the effect of different movement onset thresholds on both the reliability and absolute values of performance variables during a weightlifting derivative containing both a first and second pull. Fourteen men (age: 25.21 ± 4.14 years; body mass: 81.1 ± 11.4 kg; and 1 repetition maximum [1RM] power clean: 1.0 ± 0.2 kg·kg) participated in this study. Subjects performed the snatch-grip pull with 70% of their power clean 1RM, commencing from the mid-shank, while isolated on a force platform. Two trials were performed enabling within-session reliability of dependent variables to be determined. Three onset methods were used to identify the initiation of the lift (5% above system weight [SW], the first sample above SW, or 10 N above SW), from which a series of variables were extracted. The first peak phase peak force and all second peak phase kinetic variables were unaffected by the method of determining movement onset; however, several remaining second peak phase variables were significantly different between methods. First peak phase peak force and average force achieved excellent reliability regardless of the onset method used (coefficient of variation [CV] 0.90). Similarly, during the second peak phase, peak force, average force, and peak velocity achieved either excellent or acceptable reliability (CV 0.80) in all 3 onset conditions. The reliability was generally reduced to unacceptable levels at the first sample and 10 N method across all first peak measures except peak force. When analyzing a weightlifting derivative containing both a first and second pull, the 5% method is recommended as the preferred option of those investigated

Intra- and inter-day reliability of weightlifting variables and correlation to performance during cleans

The purpose of this investigation was to examine intra- and inter-day reliability of kinetic and kinematic variables assessed during the clean, assess their relationship to clean performance, and determine their suitability in weightlifting performance analysis. Eight competitive weightlifters performed 3 sets of single repetition cleans with 90% of their one-repetition maximum. Force-time data were collected via dual force plates with displacement-time data collected via 3-dimensional motion capture, on three separate occasions under the same testing conditions. Seventy kinetic and kinematic variables were analyzed for intra- and inter-day reliability using intraclass correlation coefficients (ICC) and the coefficient of variation (CV). Pearson’s correlation coefficients were calculated to determine relationships between barbell and body kinematics and ground reaction forces and for correlations to be deemed as statistically significant, an alpha-level of p ≤ 0.005 was set. Eleven variables were found to have ‘good’ to ‘excellent’ intra- and inter-day ICC (0.779-0.994 and 0.974-0.996, respectively) and CV (0.64-6.89% and 1.14-6.37%, respectively), with strong correlations (r = 0.880-0.988) to cleans performed at 90% 1RM. Average resultant force of the weighting 1 (W1) phase demonstrated the best intra- and inter-day reliability (ICC = 0.994 and 0.996 respectively), and very strong correlation (r = 0.981) to clean performance. Average bar power from point of lift off to peak bar height exhibited the highest correlation (r = 0.988) to clean performance. Additional reliable variables with strong correlations to clean performance were found, many of these occurred during or included the W1 phase, which suggests coaches should pay particular attention to the performance of the W1 phase

On the continuity of factorizations

[EN] Let {Xi : i ∈ I} be a set of sets, XJ :=Пi∈J Xi when Ø ≠ J ⊆ I; Y be a subset of XI , Z be a set, and f : Y → Z. Then f is said to depend on J if p, q ∈ Y , pJ = qJ ⇒ f(p) = f(q); in this case, fJ : πJ [Y ] → Z is well-defined by the rule f = fJ ◦ πJ|Y When the Xi and Z are spaces and f : Y → Z is continuous with Y dense in XI , several natural questions arise: (a) does f depend on some small J ⊆ I? (b) if it does, when is fJ continuous? (c) if fJ is continuous, when does it extend to continuous fJ : XJ → Z? (d) if fJ so extends, when does f extend to continuous f : XI → Z? (e) if f depends on some J ⊆ I and f extends to continuous f : XI → Z, when does f also depend on J? The authors offer answers (some complete, some partial) to some of these questions, together with relevant counterexamples. Theorem 1. f has a continuous extension f : XI → Z that depends on J if and only if fJ is continuous and has a continuous extension fJ : XJ → Z. Example 1. For ω ≤ k ≤ c there are a dense subset Y of [0, 1]k and f ∈ C(Y, [0, 1]) such that f depends on every nonempty J ⊆ k, there is no J ∈ [k]<ω such that fJ is continuous, and f extends continuously over [0, 1]k. Example 2. There are a Tychonoff space XI, dense Y ⊆ XI, f ∈ C(Y ), and J ∈ [I]<ω such that f depends on J, πJ [Y ] is C-embedded in XJ , and f does not extend continuously over XI .Comfort, W.; Gotchev, IS.; Recoder-Nuñez, L. (2008). On the continuity of factorizations. Applied General Topology. 9(2):263-280. doi:10.4995/agt.2008.1806.SWORD2632809