Beyond Bullying: Transforming the Culture of Peer Abuse

Bullying needs to be understood and positioned as a form of child abuse – peer abuse. For too many people, bullying is a benign term. This article will include information collected from a wide-range of researchers and discussions with over 50,000 students that I have facilitated during the past twenty years. The content will focus on new morbidities related to bullying such as depression and suicide, obesity, eating disorders, food allergies, juvenile diabetes, truancy, and substance and alcohol abuse. Making a cultural change in our society will require identified Change Agents, along with recommendations for collaboration, policies, projects and legislation.

Status and constraints of costly port rejection : a case from the Vietnamese frozen seafood export industry

While the rising exports have been the source of growth for many developing countries in recent years, the rate of commodities rejected at the ports of developed countries has also been high. Yet why it has remained so despite the costs involved is mostly unknown. This paper takes a case of the frozen seafood export industry in Vietnam and examines the current status of port rejection, roles played by various stakeholders along the value chains, and the constraints faced by the Vietnamese producers and exporters. It concludes with some policy implications, including strengthening the enforcement mechanism of standards compliance particularly at the upstream of the value chain and providing public testing labs for small-scale producers.

Response of local producers to agro-food port rejection : the case of Chinese vegetable exports

This paper analyzes the factors associated with the rejection of products at ports of importer countries and remedial actions taken by producers in China by taking as an example one of the most competitive agro-food products of China: frozen vegetables. This paper provides an overview of the vegetable production and distribution system in China and the way in which China has been participating in exports of these products. Later sections will examine in detail the frozen vegetable sector in China, identify the causes of port rejections, and the actions taken by the Chinese government and by producers, processors and exporters to improve the quality of frozen vegetable exports.

Student Reciprocal Peer Teaching as a Method for Active Learning: An Experience in an Electrotechnical Laboratory

Active learning is one of the most efficient mechanisms for learning, according to the psychology of learning. When students act as teachers for other students, the communication is more fluent and knowledge is transferred easier than in a traditional classroom. This teaching method is referred to in the literature as reciprocal peer teaching. In this study, the method is applied to laboratory sessions of a higher education institution course, and the students who act as teachers are referred to as ‘‘laboratory monitors.’’ A particular way to select the monitors and its impact in the final marks is proposed. A total of 181 students participated in the experiment, experiences with laboratory monitors are discussed, and methods for motivating and training laboratory monitors and regular students are proposed. The types of laboratory sessions that can be led by classmates are discussed. This work is related to the changes in teaching methods in the Spanish higher education system, prompted by the Bologna Process for the construction of the European Higher Education Area

Efficient random variable generation: ratio of uniforms and polar rejection sampling

Monte Carlo techniques, which require the generation of samples from some target density, are often the only alternative for performing Bayesian inference. Two classic sampling techniques to draw independent samples are the ratio of uniforms (RoU) and rejection sampling (RS). An efficient sampling algorithm is proposed combining the RoU and polar RS (i.e. RS inside a sector of a circle using polar coordinates). Its efficiency is shown in drawing samples from truncated Cauchy and Gaussian random variables, which have many important applications in signal processing and communications. RESUMEN. Método eficiente para generar algunas variables aleatorias de uso común en procesado de señal y comunicaciones (por ejemplo, Gaussianas o Cauchy truncadas) mediante la combinación de dos técnicas: "ratio of uniforms" y "rejection sampling".

Estudio probabilista del daño por choque según la metodología PEER. Aplicación a un paso superior sísmicamente aislado

En países de sismicidad moderada es habitual el uso de puentes cuyo tablero está unido mediante apoyos elastoméricos y/o deslizantes, tanto a las pilas como a los estribos. La principal vulnerabilidad sísmica de estos puentes está asociada a los choques. Dicha vulnerabilidad puede valorarse estimando la probabilidad de que se produzca un determinado daño en un periodo de tiempo. En este artículo se plantean las líneas actuales para estudiar este problema, y se aplican al estudio de la vulnerabilidad de un paso superior situado en la provincia de Granada, que puede considerarse como sísmicamente aislado. El marco del estudio es la metodología del Pacific Earthquake Engineering Research Center, cuya aplicación se ha adaptado al caso estudiado. En el artículo se describen cada una de las etapas de que consta, aunque se presta especial atención a la identificación y caracterización de los daños susceptibles de producirse. El modelo de la estructura, que debe permitir una adecuada caracterización de los choques, también será presentado en detalle. Dado que el puente es representativo de una gran cantidad de estructuras del inventario construido en España, los resultados son doblemente importantes. Por una parte, sirven de guía para la aplicación de esta metodología a estructuras similares. Y por otra, proporcionan valores de probabilidades que pueden servir de referencia.

Using multimedia and peer assessment to promote collaborative e-learning

Collaborative e-learning is increasingly appealing as a pedagogical approach that can positively affect student learning. We propose a didactical model that integrates multimedia with collaborative tools and peer assessment to foster collaborative e-learning. In this paper, we explain it and present the results of its application to the “International Seminars on Materials Science” online course. The proposed didactical model consists of five educational activities. In the first three, students review the multimedia resources proposed by the teacher in collaboration with their classmates. Then, in the last two activities, they create their own multimedia resources and assess those created by their classmates. These activities foster communication and collaboration among students and their ability to use and create multimedia resources. Our purpose is to encourage the creativity, motivation, and dynamism of the learning process for both teachers and students.

Peer Assessment and Self-assessment: Effective Learning Tools in Higher Education.

When used appropriately, self- and peer-assessment are very effective learning tools. In the present work, instructor formative assessment and feedback, self-assessment (SA), and peer-assessment (PA) have been compared. During the first part of a semester, the students followed a continuous formative assessment. Subsequently, they were divided into two subgroups based on similar performances. One subgroup performed SAs, and the other followedPAduring the last part of the course. The performances of the two groups in solving problems were compared. Results suggest that PA is a more effective learning tool than SA, and both are more effective than instructor formative assessment. However, a survey that was conducted at the end of the experiment showed higher student confidence in instructor assessment than in PA. The students recognized the usefulness of acting as peer assessors, but believed that SA helped them more than PA.

Independent doubly Adaptive Rejection Metropolis Sampling

Adaptive Rejection Metropolis Sampling (ARMS) is a wellknown MCMC scheme for generating samples from onedimensional target distributions. ARMS is widely used within Gibbs sampling, where automatic and fast samplers are often needed to draw from univariate full-conditional densities. In this work, we propose an alternative adaptive algorithm (IA2RMS) that overcomes the main drawback of ARMS (an uncomplete adaptation of the proposal in some cases), speeding up the convergence of the chain to the target. Numerical results show that IA2RMS outperforms the standard ARMS, providing a correlation among samples close to zero.

Pig but not human interferon-γ initiates human cell-mediated rejection of pig tissue in vivo

Split-thickness pig skin was transplanted on severe combined immunodeficient mice so that pig dermal microvessels spontaneously inosculated with mouse microvessels and functioned to perfuse the grafts. Pig endothelial cells in the healed grafts constitutively expressed class I and class II major histocompatibility complex molecules. Major histocompatibility complex molecule expression could be further increased by intradermal injection of pig interferon-γ (IFN-γ) but not human IFN-γ or tumor necrosis factor. Grafts injected with pig IFN-γ also developed a sparse infiltrate of mouse neutrophils and eosinophils without evidence of injury. Introduction of human peripheral blood mononuclear cells into the animals by intraperitoneal inoculation resulted in sparse perivascular mononuclear cell infiltrates in the grafts confined to the pig dermis. Injection of pig skin grafts on mice that received human peripheral blood mononuclear cells with pig IFN-γ (but not human IFN-γ or heat-inactivated pig IFN-γ) induced human CD4+ and CD8+ T cells and macrophages to more extensivley infiltrate the pig skin grafts and injure pig dermal microvessels. These findings suggest that human T cell-mediated rejection of xenotransplanted pig organs may be prevented if cellular sources of pig interferon (e.g., passenger lymphocytes) are eliminated from the graft.

CTLA4-Ig and anti-CD40 ligand prevent renal allograft rejection in primates

Selective inhibition of T cell costimulation using the B7-specific fusion protein CTLA4-Ig has been shown to induce long-term allograft survival in rodents. Antibodies preventing the interaction between CD40 and its T cell-based ligand CD154 (CD40L) have been shown in rodents to act synergistically with CTLA4-Ig. It has thus been hypothesized that these agents might be capable of inducing long-term acceptance of allografted tissues in primates. To test this hypothesis in a relevant preclinical model, CTLA4-Ig and the CD40L-specific monoclonal antibody 5C8 were tested in rhesus monkeys. Both agents effectively inhibited rhesus mixed lymphocyte reactions, but the combination was 100 times more effective than either drug alone. Renal allografts were transplanted into nephectomized rhesus monkeys shown to be disparate at major histocompatibility complex class I and class II loci. Control animals rejected in 5–8 days. Brief induction doses of CTLA4-Ig or 5C8 alone significantly prolonged rejection-free survival (20–98 days). Two of four animals treated with both agents experienced extended (>150 days) rejection-free allograft survival. Two animals treated with 5C8 alone and one animal treated with both 5C8 and CTLA4-Ig experienced late, biopsy-proven rejection, but a repeat course of their induction regimen successfully restored normal graft function. Neither drug affected peripheral T cell or B cell counts. There were no clinically evident side effects or rejections during treatment. We conclude that CTLA4-Ig and 5C8 can both prevent and reverse acute allograft rejection, significantly prolonging the survival of major histocompatibility complex-mismatched renal allografts in primates without the need for chronic immunosuppression.

A small asparagine-rich protein required for S-allele-specific pollen rejection in Nicotiana

Although S-locus RNases (S-RNases) determine the specificity of pollen rejection in self-incompatible (SI) solanaceous plants, they alone are not sufficient to cause S-allele-specific pollen rejection. To identify non-S-RNase sequences that are required for pollen rejection, a Nicotiana alata cDNA library was screened by differential hybridization. One clone, designated HT, hybridized strongly to RNA from N. alata styles but not to RNA from Nicotiana plumbaginifolia, a species known to lack one or more factors necessary for S-allele-specific pollen rejection. Sequence analysis revealed a 101-residue ORF including a putative secretion signal and an asparagine-rich domain near the C terminus. RNA blot analysis showed that the HT-transcript accumulates in the stigma and style before anthesis. The timing of HT-expression lags slightly behind SC10-RNase in SI N. alata SC10SC10 and is well correlated with the onset of S-allele-specific pollen rejection in the style. An antisense-HT construct was prepared to test for a role in pollen rejection. Transformed (N. plumbaginifolia × SI N. alata SC10SC10) hybrids with reduced levels of HT-protein continued to express SC10-RNase but failed to reject SC10-pollen. Control hybrids expressing both SC10-RNase and HT-protein showed a normal S-allele-specific pollen rejection response. We conclude that HT-protein is directly implicated in pollen rejection.

Tumor cells expressing a retroviral envelope escape immune rejection in vivo

A model system for the in vivo control of tumor cell proliferation by the immune system has been used to assay for the possible immunosuppressive activity of retroviral proteins. Expression vectors for the entire or the transmembrane subunit of the Moloney murine leukemia virus envelope protein were constructed, as well as control vectors for irrelevant transmembrane proteins—or no protein. They were introduced either into MCA205 murine tumor cells, which do not proliferate upon s.c. injection into an allogeneic host, or into CL8.1 murine tumor cells, which overexpress class I antigens and are rejected in a syngeneic host. In both cases, expression of the complete envelope protein or of the transmembrane subunit resulted in tumor growth in vivo, with no effect of control vectors. Tumor cell growth results from inhibition of the host immune response, as the envelope-dependent effect was no more observed for MCA205 cells in syngeneic mice or for CL8.1 cells in x-irradiated mice. This inhibition is local because it is not observed at the level of control tumor cells injected contralaterally. These results suggest a noncanonical function of retroviral envelopes in the “penetrance” of viral infections, as well as a possible involvement of the envelope proteins of endogenous retroviruses in tumoral processes.

Immune response to a differentiation antigen induced by altered antigen: A study of tumor rejection and autoimmunity

Recognition of self is emerging as a theme for the immune recognition of human cancer. One question is whether the immune system can actively respond to normal tissue autoantigens expressed by cancer cells. A second but related question is whether immune recognition of tissue autoantigens can actually induce tumor rejection. To address these issues, a mouse model was developed to investigate immune responses to a melanocyte differentiation antigen, tyrosinase-related protein 1 (or gp75), which is the product of the brown locus. In mice, immunization with purified syngeneic gp75 or syngeneic cells expressing gp75 failed to elicit antibody or cytotoxic T-cell responses to gp75, even when different immune adjuvants and cytokines were included. However, immunization with altered sources of gp75 antigen, in the form of either syngeneic gp75 expressed in insect cells or human gp75, elicited autoantibodies to gp75. Immunized mice rejected metastatic melanomas and developed patchy depigmentation in their coats. These studies support a model of tolerance maintained to a melanocyte differentiation antigen where tolerance can be broken by presenting sources of altered antigen (e.g., homologous xenogeneic protein or protein expressed in insect cells). Immune responses induced with these sources of altered antigen reacted with various processed forms of native, syngeneic protein and could induce both tumor rejection and autoimmunity.