A new interpretation for the degradation phenomenon of ZnO varistors

The electrical degradation phenomena of zinc oxide-based varistors were studied using a high-energy current pulse and a.c. polarization at different temperatures. Activation energy measurements during the degradation process showed that these phenomena are associated with diffusion and that the diffusion-controlling species are slower than Zn., For degradation promoted by current pulses of 8×20 μs, the Schottky potential barrier deformation was measured. A decrease in height and width of the potential barrier due to the reduction of surface states density, N s, without a significant change in donor density, N d, was observed. To explain these results, a modification of the unstable components model is proposed for the potential barrier in which the degradation is due to oxi-reduction reactions between atomic defects. These reactions promote the elimination of zinc vacancies and/or adsorbed oxygen on the grain boundaries. © 1992 Chapman & Hall.

New phenomenon of nonlinear Regge trajectory and quantum dual string theory

The relation between the spin and the mass of an infinite number of particles in a q-deformed dual string theory is studied. For the deformation parameter q a root of unity, in addition to the relation of such values of q with the rational conformal field theory, the Fock space of each oscillator mode in the Fubini-Veneziano operator formulation becomes truncated. Thus, based on general physical grounds, the resulting spin-(mass)2 relation is expected to be below the usual linear trajectory. For such specific values of q, we find that the linear Regge trajectory turns into a square-root trajectory as the mass increases.

The phenomenon of photoinhibition of photosynthesis and its importance in reforestation

Photoinhibition, defined as the inhibition of photosynthesis caused by excessive radiance, affects field production to a great extent. This phenomenon is particularly relevant in reforestation practices, when one deals with forests of rapid growth such as Eucalyptus. The imposition of additional stress factors during exposure to high radiance increases the potential for photoinhibitory effects, so the inhibition of photosynthesis indicates that the plant is submitted to stressful conditions. Photoinhibition can be reversible, playing a protective role for the photosynthetic systems, but it can also reflect damage that has already occurred in the photosynthetic apparatus, being irreversible in this case. In this review, we present the physiological and molecular mechanisms of photoinhibition and discuss the interaction between light and other stress factors and its effects on plants destined for reforestation. In addition, the present work analyzes some of the features and strategies that help plants avoid or restrict the occurrence of photoinhibition. For instance, pigments and enzymes which naturally occur in plants can prevent photoinhibition, while preadaptation to nonideal conditions can enhance tolerance to a certain stress factor. Most of these morphological, metabolic, and biochemical mechanisms of defense are related to the dissipation of excessive energy such as heat. Understanding these mechanisms can help improve cultivation procedures, avoid the plants' death, and increase productivity in the field.

The phenomenon of ageing and the situation of older persons in the Caribbean

Includes bibliography

Give me a shilling [videorecording]: phenomenon of the street children

Pictures of the Watoto wa Lwanga project, the efforts of the Brothers of St. Charles Lwanga not only to rehabilitate Nairobi's street children, but to prevent slum children from ending up in the streets. Features life in the slums, the situation of the street children, the efforts of the social workers to involve the children's parents, the various reception centers, the vocational school, the Boy's Town Ruai Residential School, the community of the Brothers of St. Charles Lwanga as well as interviews with former street children and with various directors and benefactors of the project.

Homo Jihadicus. Islam in the former USSR and the phenomenon of the post-Soviet militants in Syria and Iraq. OSW REPORT 2015-09-21

The post-Soviet area, along with the countries of the Middle East, North Africa and Western Europe, have become one of the main global exporters of Islamic militants. Currently on the territory of Syria, and to a lesser extent of Iraq, there are several thousands of foreign fighters from the post-Soviet states. The causes of the war migration from the former USSR states to the Middle East have their roots in the dynamic changes taking place inside Islam in the post-Soviet area: primarily the growth of Salafism and militant Islam, as well as the internationalisation and globalisation of the local Islam. The deep political, economic, social and ideological changes which Muslims underwent after the collapse of the USSR, led to the creation of a specific group within them, for which Islam in its radical form became the main element of their identity. Homo sovieticus, without fully eradicating his Soviet part, became Homo jihadicus who not only identifies himself with the global Ummah, but is also ready to leave his country and join jihad beyond its borders in the name of the professed ideas.

A problem in Greek ethics, being an inquiry into the phenomenon of sexual inversion, addressed especially to medical psychologists and jurists /

Mode of access: Internet.

Human rights and the phenomenon of disappearances [microform] : hearings before the Subcommittee on International Organizations of the Committee on Foreign Affairs, House of Representatives, Ninety-sixth Congress, first session, September 20, 25, and October 18, 1979.

Reuse of record except for individual research requires license from Congressional Information Service, Inc.

A qualitative study of the impact of an educational intervention on older parents of adults with disabilities engaged in the phenomenon of future-care planning

This phenomenological study describes the impact of an educational intervention on the day-to-day experiences of older parent caregivers of adults with developmental disabilities who were engaged in the process of future-care planning. Qualitative strategies of individual and focus group interviewing were used with a purposive sample of older caregivers. Participants were members of an existing parent support group. Twenty-three caregivers representing 18 families were queried before and after the education program. The disabilities represented were mental retardation, cerebral palsy and autism. Parents whose children live at or away from home were included. The intervention was conducted on five Saturdays over a two month period; the duration of the study was five months. Findings used typical words of the respondents from their individual and focus group interviews to describe feelings, attitudes and experiences in making future-care plans. Data from verbatim transcriptions and researcher's field notes were coded, analyzed, sorted into themes, and subjected to interpretive analysis. Respondents showed a positive change in attitudes and actions after participating in the education program, regardless of their initial stage in care planning. Fears were replaced by hope and determination; hesitation and ineptitude by feelings of competence and confidence; and procrastination and delay by purposeful actions. Other key findings: use of a planning document greatly aided caregivers; barriers to planning were often intrinsic and amenable to education; residential plans were the most difficult aspect of planning; listening to the experiences of other parent caregivers was helpful; and making burial plans for their offspring was one aspect of planning parents wished to do themselves. ^