Absorbed power of small children

Objective. To experimentally measure the seated vertical direction whole-body absorbed power characteristics of small children less than 18 kg in mass. Background. Several studies have reported whole-body absorbed power for adult humans, but no data has been published previously for small children. Methods. Eight children were tested in a laboratory test rig which incorporated safety features which satisfy existing international standards for human testing. Force and acceleration were measured at the point of input to a rigid seat at a sampling rate of 200 Hz, and analysis was performed over the interval from 1.0 to 45.0 Hz. A double normalised (both input acceleration and test subject mass) measure of absorbed power was used. Results. The vertical whole-body power absorption characteristics of the small children were found to present differences with respect to those of adults. The mean frequency of peak absorption was found to be 7.4 Hz as opposed to approximately 4.0–5.0 for adults. The interval of absorption was found to be from approximately 3 to 16 Hz and the total double normalised absorbed power was found to be 86% that of adults. Conclusions. The differences in dynamic response between small children and adults raise questions regarding the applicability of whole-body vibration guidelines such as ISO-2631 in the case of small children since these guidelines were developed from mechanical and subjective response data of adults

The Ideal Intersection Property for Groupoid Graded Rings

We show that if a groupoid graded ring has a certain nonzero ideal property, then the commutant of the center of the principal component of the ring has the ideal intersection property, that is it intersects nontrivially every nonzero ideal of the ring. Furthermore, we show that for skew groupoid algebras with commutative principal component, the principal component is maximal commutative if and only if it has the ideal intersection property

Inert Doublet Model and LEP II Limits

The inert doublet model is a minimal extension of the standard model introducing an additional SU(2) doublet with new scalar particles that could be produced at accelerators. While there exists no LEP II analysis dedicated for these inert scalars, the absence of a signal within searches for supersymmetric neutralinos can be used to constrain the inert doublet model. This translation however requires some care because of the different properties of the inert scalars and the neutralinos. We investigate what restrictions an existing DELPHI collaboration study of neutralino pair production can put on the inert scalars and discuss the result in connection with dark matter. We find that although an important part of the inert doublet model parameter space can be excluded by the LEP II data, the lightest inert particle still constitutes a valid dark matter candidate.Comment: 12 pages, 9 figures; v2: published versio

The root-soil system of Norway spruce subjected to turning moment: resistance as a function of rotation

The reactions of trees to wind, rockfall, and snow and debris flow depend largely on how strong and deformable their anchorage in the soil is. Here, the resistive turning moment M of the root–soil system as a function of the rotation ϕ at the stem base plays the major role. M(ϕ) describes the behavior of the root– soil system when subject to rotational moment, with the maximum M(ϕ) indicating the anchorage strength M a of the tree. We assessed M(ϕ) of 66 Norway spruce (Picea abies L. Karst) by pulling them over with a winch. These 45- to 170-year-old trees grew at sites of low and high elevation, with a diameter at breast height DBH = 14–69 cm and a height H =  9–42 m. M(ϕ) displayed a strong nonlinear behavior. M a was reached at a lower ϕ for large trees than for small trees. Thus overhanging tree weight contributed less to M a for the large trees. Overturning also occurred at a lower ϕ for the large trees. These observations show that the rotational ductility of the root–soil system is higher for small trees. M a could be described by four monovariate linear regression equations of tree weight, stem weight, stem volume and DBH ² ·H (0.80 R ² ϕ at M a, ϕ a, by a power law of DBH²·H (R ² = 0.85). We found significantly higher M a for the low-elevation spruces than for the high-elevation spruces, which were more shallowly anchored, but no significant difference in ϕ a. The 66 curves of M(ϕ), normalized (n) by M a in M-direction and by ϕ a in ϕ-direction, yielded one characteristic average curve: Mn (ϕn) M¯nϕn . Using this average curve and the predictions of M a and ϕ a, it is shown that M(ϕ) and the curves associated with M(ϕ) can be predicted with a relative standard error ≤25%. The parameterization of M(ϕ) by tree size and weight is novel and provides useful information for predicting with finite-element computer models how trees will react to natural hazards

Skew Category Algebras Associated with Partially Defined Dynamical Systems

We introduce partially defined dynamical systems defined on a topological space. To each such system we associate a functor $s$ from a category $G$ to \Top^{\op} and show that it defines what we call a skew category algebra $A \rtimes^{\sigma} G$. We study the connection between topological freeness of $s$ and, on the one hand, ideal properties of $A \rtimes^{\sigma} G$ and, on the other hand, maximal commutativity of $A$ in $A \rtimes^{\sigma} G$. In particular, we show that if $G$ is a groupoid and for each e \in \ob(G) the group of all morphisms $e \rightarrow e$ is countable and the topological space $s(e)$ is Tychonoff and Baire, then the following assertions are equivalent: (i) $s$ is topologically free; (ii) $A$ has the ideal intersection property, that is if $I$ is a nonzero ideal of $A \rtimes^{\sigma} G$, then $I \cap A \neq \{0\}$; (iii) the ring $A$ is a maximal abelian complex subalgebra of $A \rtimes^{\sigma} G$. Thereby, we generalize a result by Svensson, Silvestrov and de Jeu from the additive group of integers to a large class of groupoids.Comment: 16 pages. This article is an improvement of, and hereby a replacement for, version 1 (arXiv:1006.4776v1) entitled "Category Dynamical Systems and Skew Category Algebras

Estimates of size of cycle in a predator-prey system II

We prove estimates for the maximal and minimal predator and prey populations on the unique limit cycle in a standard predator-prey system. Our estimates are valid when the cycle exhibits small predator and prey abundances and large amplitudes. The proofs consist of constructions of several Lyapunov-type functions and derivation of a large number of non-trivial estimates, and should be of independent interest. This study generalizes results proved by the authors in (Differ Equ Dyn Syst 30, 131-159 (2022)) to a wider class of systems and, in addition, it gives simpler proofs of some already known estimates

A new low mass for the Hercules dSph: the end of a common mass scale for the dwarfs?

We present a new mass estimate for the Hercules dwarf spheroidal galaxy (dSph), based on the revised velocity dispersion obtained by Aden et al. (2009, arXiv:0908.3489). The removal of a significant foreground contamination using newly acquired Stromgren photometry has resulted in a reduced velocity dispersion. Using this new velocity dispersion of 3.72 +/- 0.91 km/s, we find a mass of M_300=1.9^{+1.1}_{-0.8} 10^6 M_sun within the central 300 pc, which is also the half-light radius, and a mass of M_433=3.7_{-1.6}^{+2.2} 10^6 M_sun within the reach of our data to 433 pc, significantly lower than previous estimates. We derive an overall mass-to-light ratio of M_433/L=103^{+83}_{-48} M_sun/L_sun. Our mass estimate calls into question recent claims of a common mass scale for dSph galaxies. Additionally, we find tentative evidence for a velocity gradient in our kinematic data of 16 +/- 3 km/s/kpc, and evidence of an asymmetric extension in the light distribution at about 0.5 kpc. We explore the possibility that these features are due to tidal interactions with the Milky Way. We show that there is a self-consistent model in which Hercules has an assumed tidal radius of r_t = 485 pc, an orbital pericentre of r_p = 18.5 +/- 5 kpc, and a mass within r_t of M_{tid,r_t}=5.2 +/- 2.7 10^6 M_sun. Proper motions are required to test this model. Although we cannot exclude models in which Hercules contains no dark matter, we argue that Hercules is more likely to be a dark matter dominated system which is currently experiencing some tidal disturbance of its outer parts.Comment: 10 pages, 3 figures, Accepted for publication by ApJ

Pengelolaan Teacher Capacity Building (Tcb) Untuk Meningkatkan Profesionalitas Guru (Studi Kasus Guru SMPN 2 Dan SMP Darul Hikam Bandung)

Teacher Capacity Building (TCB) is a key point for a quality education service provided by a school. In the reality, schools have no standardize TCB system to ensure that their TCB is conducted effectivity and efficiently. The research was conducted to figure out the answers to four main questions related to the steps taken in determining the TCB policy at school, the TCB management, the quality assurance system, and the impacts of TCB either for the teacher as an individual, for learning quality, or for school quality. The location of the research were SMPN 2 Bandung and SMP Darul Hikam Bandung as the representation of school with their own school policy on TCB. The reasearch was a qualitative reaserch with descriptive method. The data was callected using three major techniques: observation, indeepth interview, and documentary study. The research revealed that the TCB in SMP Darul Hikam is basen on need analysis, the power of the leader, the tandardized recruitment, and teacher performance assessment. In SMPN 2 Bandung the TCB is empowered by the networking and a very health atmosphere for the teacher to show their best performances. The research also found that the aspects needs to be improved in the implementation of the TCB in both schools are the documentary and the quality assurance

Privacy Mining from IoT-based Smart Homes

Recently, a wide range of smart devices are deployed in a variety of environments to improve the quality of human life. One of the important IoT-based applications is smart homes for healthcare, especially for elders. IoT-based smart homes enable elders' health to be properly monitored and taken care of. However, elders' privacy might be disclosed from smart homes due to non-fully protected network communication or other reasons. To demonstrate how serious this issue is, we introduce in this paper a Privacy Mining Approach (PMA) to mine privacy from smart homes by conducting a series of deductions and analyses on sensor datasets generated by smart homes. The experimental results demonstrate that PMA is able to deduce a global sensor topology for a smart home and disclose elders' privacy in terms of their house layouts.Comment: This paper, which has 11 pages and 7 figures, has been accepted BWCCA 2018 on 13th August 201