Impact-induced intracranial pressure caused by an accelerated motion of the head or by skull deformation; an experimental study using physical models of the head and neck, and ones of the skull

An impact incurred by the movable head may bring about a change in intracranial pressure and this change may play an important part in the occurrence of the cerebral contusion. We have carried out the following experiments to determine whether the intracranial pressure change was attributed to an accelerated motion of the head or to a skull deformation. In the blow experiment in which the head was accelerated, a positive peak in the intracranial pressure was recorded immediately after impact at the impact site and a negative one at a site opposite the impact. In the one in which the skull could be deformed, the intracranial pressure curves at both sites contained harmonics. The modal analysis revealed an inbending in the frontal and occipital regions of the skull and an outbending in the parietal and temporal regions immediately after impact, followed by a reverse deformation. Regarding the intracranial pressure change, positive pressures were recorded in the frontal and occipital regions immediately after impact, followed by a negative one. This study demonstrated that the positive and negative peaks were caused by the accelerated motion of the head, and that the curve of the intracranial pressure changes contained harmonics which were caused by the deformation of the skull.     

Gendered Pathways to Bullying Perpetration via Social Achievement Goals – Mediating Effects of Sense of Belonging and Non-inclusive Group Norms

ABSTRACT

This study investigated the gender-specific effects of social achievement goals – i.e., social development goals, social demonstration approach goals, and social demonstration avoid goals – on bullying perpetration in a sample of 788 adolescents (53.3% girls), taking into account the mediating role of sense of belonging and non-inclusive group norms. Two-group structural equation modeling results indicated that social demonstration approach goals positively predicted bullying perpetration for both genders. For girls, higher social development goals and for boys, higher social avoidance goals decreased bullying perpetration. Gender-specific effects of belonging and non-inclusive group norms on bullying perpetration occurred. For boys, non-inclusive group norms mediated the relation between all social achievement goals and bullying perpetration. Implications for future research and (gender-sensitive) bullying interventions are discussed.     

“They Think that I Should Defend”: Effects of Peer and Teacher Injunctive Norms on Defending Victimized Classmates in Early Adolescents

Norms have been suggested as important characteristics of the social-ecological context for defending victimized peers, but little is known about the contribution of student perceived injunctive norms (regarding the appropriateness of defending) imposed by peers and teachers. To investigate the role of these norms in defending, a sample of 751 early adolescents (51% female; M_age at Time 1:13 years) was assessed at two time points. Defending, as measured by peer- and self-ratings, decreased slightly over a six-month timespan. Three-level models (with time, students, and classrooms as the levels) indicated that both individual- and classroom-level perceived peer injunctive norms (but not teacher injunctive norms) had positive effects on defending over time regardless of the source of the information on defending (peers or self). These findings support programs that encourage defending through peer norms.     

The politics of Japan’s rice trade

This article analyzes both the domestic and international political factors that affect Japan’s rice trade policy. Based on the analysis, this article suggests that although Japan will open its rice market soon, the rice trade liberalization is likely to proceed very slowly and will be accompanied by a temporary surge of nontariff barriers. Domestically, a national coalition of producers, distributors, nationalists, politicians, bureaucrats, environmentalists, and consumers will delay and distort any rice trade liberalization program. Internationally, the pressure to further reduce rice trade barriers will decline due to the controversy over agricultural trade liberalization in the GATT negotiation, the lack of significant political pressure by politicians and interest groups within the United States, and Japan’s record of trade liberalization, especially in agricultural trade. He is the author ofInstitutions and Global Competitiveness (Pittsburgh, PA: University of Pittsburgh Press, 1994).     

Differences in the intracranial pressure caused by a 'blow' and/or a 'fall'--an experimental study using physical models of the head and neck

In cases of a severe head injury caused by a fall, coup contusions are either absent or very minor, in contrast to presence of extensive contre-coup damage. In cases of a severe blow to head, however, the reverse occurs, with contre-coup lesions a rarity and coup damage extensive. To investigate this further, head injuries caused by a 'blow' or a 'fall' have been studied, using physical human models of the head and neck, both filled with distilled, degassed water and fixed onto a dummy torso. An impact of a constant magnitude was applied to the midoccipital region in 'blow' and 'fall' experiments, and the acceleration of the head and changes in the intracranial pressure were measured, with the resulting data analyzed by a computer. In both experiments, the peak amplitude of the acceleration pulse were almost the same. Similarly, the intracranial pressure curve at the impact site consisted of a positive pulse that hardly differed, nor did the peak amplitude of that pulse vary significantly. In the 'blow' experiment, however, the intracranial pressure curve at the site opposite the impact consisted of a negative pulse, whereas in the 'fall' experiment, the intracranial pressure recorded at the same area was negative but of a longer duration, with an absolute value that was slightly greater. Our results indicate that an impact to the head triggers a different response in the intracranial space, dependent on whether that impact force was caused by a 'blow' or a 'fall'.     

Understanding for Which Students and Classes a Socio-Ecological Aggression Prevention Program Works Best: Testing Individual Student and Class Level Moderators

Journal of Youth and Adolescence - School-based aggression prevention programs may not be equally effective for all students and classes, depending on student and class characteristics. This study...     

Development of heavy mineral and heavy element database of soil sediments in Japan using synchrotron radiation X-ray powder diffraction and high-energy (116 keV) X-ray fluorescence analysis: 1. Case study of Kofu and Chiba region

We have started the construction of a nationwide forensic soil sediment database for Japan based on the heavy mineral and trace heavy element compositions of stream sediments collected at 3024 points all over Japan obtained by high-resolution synchrotron X-ray powder diffraction (SR-XRD) and high-energy synchrotron X-ray fluorescence analysis (HE-SR-XRF). In this study, the performance of both techniques was demonstrated by analyzing soil sediments from two different geological regions, the Kofu and Chiba regions in Kanto province, to construct database that can be applied in the future to provenance analysis of soil evidence from a crime scene. The sediments from the quaternary volcanic lithology of the Chiba region were found to be dominated by heavy minerals of volcanic origin - orthopyroxene, clinopyroxene, and amphibole, and the REEs (rare earth elements) within the region showed similar geochemical behavior. On the other hand, four distinct heavy mineral groups were identified in the sediments of the Kofu region, where there is a great variety of underlying bedrock, and the geochemical behavior of the REEs in the sediments also varied accordingly to their geological origins. As such, our study shows that high-resolution SR-XRD data can provide information on the spatial distribution patterns of heavy minerals in stream sediments, playing an important role in determining their likely geographical origin. Meanwhile, the highly sensitive HE-SR-XRF data allow us to study the geochemical behavior of trace heavy elements, especially the REEs in the sediments, providing additional support to further constrain the likely geographical origin of the sediments determined by heavy minerals.