Combined effect of frustration and dimerization in ferrimagnetic chains and square lattice

Within the zero-temperature linear spin-wave theory we have investigated the effect of frustration and dimerization of a Heisenberg system with alternating spins $s_{1}$ and $s_{2}$ on one- and two-dimensional lattices. The combined effect most visibly appears in the elementary excitation spectra. In contrast to the ground state energy that decreases with dimerization and increases with frustration, the excitation energies are shown to be suppressed in energy by both dimerization and frustration. The threshold value of frustration that signals a transition from a classical ferrimagnetic state to a spiral state, decreases with dimerization, showing that dimerization further helps in the phase transition. The correlation length and sublattice magnetization decrease with both dimerization and frustration indicating the destruction of the long-range classical ferrimagnetic. The linear spin wave theory shows that in the case of a square lattice, dimerization initially opposes the frustration-led transition to a spiral magnetic state, but then higher magnitudes of lattice deformation facilitate the transition. It also shows that the transition to spiral state is inhibited in a square lattice beyond a certain value of dimerization.Comment: 8 pages, latex, 12 postscript figure

Knowledge and Attitudes of Young People toward Mental Illness: A Cross Sectional Study

The aim of the study was to investigate young Jordanians’ knowledge and attitudes toward people who have a mental illness. A cross sectional design was utilized. A convenient sample of 858 participants aged between 15–24 years old completed a survey. Participants under 19 years were accessed through their schools and those 19 years and above were accessed through universities. Results showed that although the majority of university and school students’ responses were generally consistent, they disagreed on 11 items on the survey; for example, 186 (39.3%) of university students agreed that mental illness has a biological origin compared with only 119 (30%) of school students. The majority of young people 737 (85.9%) were willing to learn and 792 (92.3%) felt that they have to help people with mental illness, which make them willing to learn. In conclusion, the findings provide insights for decision makers and researchers in Jordan about young peoples’ knowledge and attitudes toward mental illness. Increasing young adults’ literacy through introducing educational programs such as mental health first aid courses will enrich their knowledge; help change attitudes and reduce stigma toward people living with mental illness

Mcl-1 is a key regulator of the ovarian reserve

A majority of ovarian follicles are lost to natural death, but the disruption of factors involved in maintenance of the oocyte pool results in a further untimely follicular depletion known as premature ovarian failure. The anti-apoptotic B-cell lymphoma 2 (Bcl-2) family member myeloid cell leukemia-1 (MCL-1) has a pro-survival role in various cell types; however, its contribution to oocyte survival is unconfirmed. We present a phenotypic characterization of oocytes deficient in Mcl-1, and establish its role in maintenance of the primordial follicle (PMF) pool, growing oocyte survival and oocyte quality. Mcl-1 depletion resulted in the premature exhaustion of the ovarian reserve, characterized by early PMF loss because of activation of apoptosis. The increasingly diminished surviving cohort of growing oocytes displayed elevated markers of autophagy and mitochondrial dysfunction. Mcl-1-deficient ovulated oocytes demonstrated an increased susceptibility to cellular fragmentation with activation of the apoptotic cascade. Concomitant deletion of the pro-apoptotic Bcl-2 member Bcl-2-associated X protein (Bax) rescued the PMF phenotype and ovulated oocyte death, but did not prevent the mitochondrial dysfunction associated with Mcl-1 deficiency and could not rescue long-term breeding performance. We thus recognize MCL-1 as the essential survival factor required for conservation of the postnatal PMF pool, growing follicle survival and effective oocyte mitochondrial function

Conformational flexibility of the oncogenic protein LMO2 primes the formation of the multi-protein transcription complex

LMO2 was discovered via chromosomal translocations in T-cell leukaemia and shown normally to be essential for haematopoiesis. LMO2 is made up of two LIM only domains (thus it is a LIM-only protein) and forms a bridge in a multi-protein complex. We have studied the mechanism of formation of this complex using a single domain antibody fragment that inhibits LMO2 by sequestering it in a non-functional form. The crystal structure of LMO2 with this antibody fragment has been solved revealing a conformational difference in the positioning and angle between the two LIM domains compared with its normal binding. This contortion occurs by bending at a central helical region of LMO2. This is a unique mechanism for inhibiting an intracellular protein function and the structural contusion implies a model in which newly synthesized, intrinsically disordered LMO2 binds to a partner protein nucleating further interactions and suggests approaches for therapeutic targeting of LMO2

Polyimide-Planarized Vertical-Cavity Surface-Emitting Lasers With 17.0-GHz Bandwidth

Abstract-High-speed oxide-confined polyimide-planarized 850-nm vertical-cavity surface-emitting lasers exhibit 3-dB modulation bandwidths up to 17.0 GHz. The devices are fabricated using a reproducible, simple process incorporating polyimide with good adhesion that does not require implantation or semiinsulating substrates to achieve low capacitance

Multifaceted needs of individuals living with peripheral arterial disease: a qualitative study

Objectives To ascertain a comprehensive perspective of the impact of peripheral arterial disease (PAD) on people including needs for access to disease specific information, education, services, and support. Methods Participants were recruited from outpatient clinics at a tertiary hospital in metropolitan Australia. Telephone and face-to-face semi-structured interviews were conducted with nine individuals living with PAD and analysed using qualitative content thematic analysis. Results The nine participants were on average 74.2 (SD 10.9) years and predominantly women (67%). Lack of understanding of PAD and inconsistent information resulted in confusion regarding self-management strategies. Effects of pain and mobility problems were amplified for participants who lived alone and did not have an informal carer. Discussion Poor quality of life in PAD reflects pain, social isolation and fear of falls. Multidisciplinary teams with case managers should consider older people’s living situations and needs for additional support services and education to facilitate integrated care

Thermodynamic properties of the two-dimensional S=1/2 Heisenberg antiferromagnet coupled to bond phonons

By applying a quantum Monte Carlo procedure based on the loop algorithm we investigate thermodynamic properties of the two-dimensional antiferromagnetic S=1/2 Heisenberg model coupled to Einstein phonons on the bonds. The temperature dependence of the magnetic susceptibility, mean phonon occupation numbers and the specific heat are discussed in detail. We study the spin correlation function both in the regime of weak and strong spin phonon coupling (coupling constants g=0.1, w=8J and g=2, w=2J, respectively). A finite size scaling analysis of the correlation length indicates that in both cases long range Neel order is established in the ground state.Comment: 10 pages, 13 figure

The Reality of Distance Learning Skills among General Education Teachers from the Point of View of Supervisors and School Principals

This study examined the reality of distance learning skills among public education teachers from the point of view of supervisors and principals. The study aimed at identifying statistically significant differences in the average responses of the participants about the reality of distance learning skills among public education teachers in Asir region due to the study variables (job title, years of experience, gender, educational qualification, job rank, number of educational programs). The study used the descriptive approach to achieve the objectives of the study, and a questionnaire was designed for data collection and analysis. The study sample consisted of (245) supervisors and principals. The results of the study showed that the degree to which general education teachers possessed distance learning skills came to a large degree. The findings showed that there were no statistically significant differences in the average responses of respondents about distance learning skills due to the job title variable, and the presence of statistically significant differences in the average responses of the respondents about distance learning skills. The findings also revealed statistically significant differences in the averages of respondents’ responses about distance learning skills due to the variable of gender, with the exception of the field of “skills of using applied programs for information technology”, as well. The results showed that there were no statistically significant differences in the averages of the respondents’ responses about the areas of distance learning skills due to the educational qualification variable. There were statistically significant differences in the averages of the respondents’ responses in the areas of “educational software design skills, skills of using applied programs for information technology” due to the variable of occupational rank. There was a presence of statistically significant differences in the average responses of the respondents in the areas of skills of using application programs for information technology, due to the variable number of training programs

Deterministic control of magnetic vortex wall chirality by electric field

Concepts for information storage and logical processing based on magnetic domain walls have great potential for implementation in future information and communications technologies. To date, the need to apply power hungry magnetic fields or heat dissipating spin polarized currents to manipulate magnetic domain walls has limited the development of such technologies. The possibility of controlling magnetic domain walls using voltages offers an energy efficient route to overcome these limitations. Here we show that a voltage-induced uniaxial strain induces reversible deterministic switching of the chirality of a magnetic vortex wall. We discuss how this functionality will be applicable to schemes for information storage and logical processing, making a significant step towards the practical implementation of magnetic domain walls in energy efficient computing