When does national identification lead to the rejection of immigrants? Cross-sectional and longitudinal evidence for the role of essentialist in-group definitions

Two studies were carried out in England to investigate the role of essentialist national group definitions in determining the effect of national identification on prejudice towards immigrants, and asylum seekers in particular. It was expected that the relationship between national identification and prejudice would depend on the degree to which participants endorse an essentialist (`ethnic') definition of their nationality. Consistent with this, Study 1 (N=154) found that national identification is associated with negativity towards asylum seekers only among individuals who endorse an essentialist conception of the group, and shows no significant association with prejudice among those who reject such a conception. Study 2 (N=219) used a longitudinal design conducted over 6 weeks, allowing cross-lagged analysis of causality between essentialism, identification, and behavioural intentions towards asylum seekers. A causal effect of essentialism on willingness to support a group acting against asylum seekers was observed, with no significant causal effect in the reverse direction. The reverse causal direction was observed in the case of support for a group seeking to support asylum seekers, with intended behaviours determining essentialism. The results are discussed in terms of the importance of group definitions in the study of in-group affiliations and prejudice.

The Role of Direct Presentation by Donor Dendritic Cells in Rejection of Minor Histocompatibility Antigen-Mismatched Skin and Hematopoietic Cell Grafts

Background. The success of transplantation is hampered by rejection of the graft by alloreactive T cells. Donor dendritic cells (DC) have been shown to be required for direct priming of immune responses to antigens from major histocompatibility complex-mismatched grafts. However, for immune responses to major histocompatibility complex-matched, minor histocompatibility (H) antigen mismatched grafts, the magnitude of the T-cell response to directly presented antigens is reduced, and the indirect pathway is more important. Therefore, we aimed to investigate the requirement for donor DC to directly present antigen from minor H antigen mismatched skin and hematopoietic grafts.

Corneal Allograft Rejection:Risk Factors, Diagnosis, Prevention, and Treatment

Recent advances in corneal graft technology, including donor tissue retrieval, storage and surgical techniques, have greatly improved the clinical outcome of corneal grafts. Despite these advances, immune mediated corneal graft rejection remains the single most important cause of corneal graft failure. Several host factors have been identified as conferring a "high risk" status to the host. These include: more than two quadrant vascularisation, with associated lymphatics, which augment the afferent and efferent arc of the immune response; herpes simplex keratitis; uveitis; silicone oil keratopathy; previous failed (rejected) grafts; "hot eyes"; young recipient age; and multiple surgical procedures at the time of grafting. Large grafts, by virtue of being closer to the host limbus, with its complement of vessels and antigen-presenting Langerhans cells, also are more susceptible to rejection. The diagnosis of graft rejection is entirely clinical and in its early stages the clinical signs could be subtle. Graft rejection is largely mediated by the major histocompatibility antigens, minor antigens and perhaps blood group ABO antigens and some cornea-specific antigens. Just as rejection is mediated by active immune mediated events, the lack of rejection (tolerance) is also sustained by active immune regulatory mechanisms. The anterior chamber associated immune deviation (ACAID) and probably, conjunctiva associated lymphoid tissue (CALT) induced mucosal tolerance, besides others, play an important role. Although graft rejection can lead to graft failure, most rejections can be readily controlled if appropriate management is commenced at the proper time. Topical steroids are the mainstay of graft rejection management. In the high-risk situations however, systemic steroids, and other immunosuppressive drugs such as cyclosporin and tacrolimus (FK506) are of proven benefit, both for treatment and prevention of rejection.

Serial chimerism analyses indicate that mixed haemopoietic chimerism influences the probability of graft rejection and disease recurrence following allogeneic stem cell transplantation (SCT) for severe aplastic anaemia (SAA): indication for routine assessment of chimerism post SCT for SAA

Ninety-one patients were studied serially for chimeric status following allogeneic stem cell transplantation (SCT) for severe aplastic anaemia (SAA) or Fanconi Anaemia (FA). Short tandem repeat polymerase chain reaction (STR-PCR) was used to stratify patients into five groups: (A) complete donor chimeras (n = 39), (B) transient mixed chimeras (n = 15) (C) stable mixed chimeras (n = 18), (D) progressive mixed chimeras (n = 14) (E) recipient chimeras with early graft rejection (n = 5). As serial sampling was not possible in Group E, serial chimerism results for 86 patients were available for analysis. The following factors were analysed for association with chimeric status: age, sex match, donor type, aetiology of aplasia, source of stem cells, number of cells engrafted, conditioning regimen, graft-versus-host disease (GvHD) prophylaxis, occurrence of acute and chronic GvHD and survival. Progressive mixed chimeras (PMCs) were at high risk of late graft rejection (n = 10, P <0.0001). Seven of these patients lost their graft during withdrawal of immunosuppressive therapy. STR-PCR indicated an inverse correlation between detection of recipient cells post-SCT and occurrence of acute GvHD (P = 0.008). PMC was a bad prognostic indicator of survival (P = 0.003). Monitoring of chimeric status during cyclosporin withdrawal may facilitate therapeutic intervention to prevent late graft rejection in patients transplanted for SAA.

Rejection, Shaming, Enclosure, and Moving On: Variant Experiences and Meaning Among Loyalist Former Prisoners:Variant Experiences and Meaning Among Loyalist Former Prisoners

This article unpacks the variant meanings, perceptions, and experiences of violent enactment and stigmatic shaming among loyalists with regard to rejection, harm, and masking. What we locate is a landscape of variable emotions, experiences, neutralization techniques, dependences, and embedded forms of fatalism as well as resilience. Attending to those alternate positions and well-beings is important in considering the capacity of re-integration and the presently uneven nature of it. In adopting an account-driven format we present and analyze how involvement in violent conflict can, on the one hand, provoke persistence and senses of transitional thinking and on the other engender rejection and related fatalistic attitudes.

Rejection of the second allogeneic graft in a patient with severe aplastic anemia reversed by antilymphocyte globulin and donor lymphocyte infusions

Rejection after allogeneic BMT for aplastic anemia is a complication with a high risk of mortality. We describe a patient who, following a second episode of rejection after a second BMT entered a third durable remission subsequent to treatment with ALG, donor lymphocyte infusions, GM-CSF, and erythropoietin. Therapy was well tolerated. At 5 years after rejection treatment, his hematopoiesis is of complete donor origin as determined by analyses of short tandem repeats. Thus, donor lymphocyte infusions can be considered as a therapy option for marrow rejection after allogeneic BMT for aplastic anemia.

Ultraviolet irradiation for the prevention of graft-versus-host disease and graft rejection in bone marrow transplantation

This review describes an approach to the prevention of graft-versus-host disease (GVHD) and graft rejection following allogeneic BMT that differs from conventional methods. Ultraviolet (UV) irradiation inhibits the proliferative responses of lymphoid cells to mitogens and alloantigens by inactivation of T lymphocytes and dendritic cells, and in animal models this can prevent both GVHD and graft rejection. It is important that the marrow repopulating capacity of haemopoietic stem cells is not damaged by the irradiation process. We have found that polymorphic microsatellite markers are a sensitive way of assessing the impact of UV irradiation on chimerism after BMT in rodents.

Adaptive self-calibrating image rejection receiver

An adaptive self-calibrating image rejection receiver is described, containing a modified Weaver image rejection mixer and a Digital Image Rejection Processor (DIRP). The blind source-separation-based DIRP eliminates the I/Q errors improving the Image Rejection Ratio (IRR) without the need for trimming or use of power-hungry discrete components. Hardware complexity is minimal, requiring only two complex coefficients; hence it can be easily integrated into the signal processing path of any receiver. Simulation results show that the proposed approach achieves 75-97 dB of IRR.

Design and low-power implementation of an adaptive image rejection receiver

This paper deals with and details the design and implementation of a low-power; hardware-efficient adaptive self-calibrating image rejection receiver based on blind-source-separation that alleviates the RF analog front-end impairments. Hybrid strength-reduced and re-scheduled data-flow, low-power implementation of the adaptive self-calibration algorithm is developed and its efficiency is demonstrated through simulation case studies. A behavioral and structural model is developed in Matlab as well as a low-level architectural design in VHDL providing valuable test benches for the performance measures undertaken on the detailed algorithms and structures.

Design of a power-aware digital image rejection receiver

This paper deals with and details the design of a power-aware adaptive digital image rejection receiver based on blind-source-separation that alleviates the RF analog front-end impairments. Power-aware system design at the RTL level without having to redesign arithmetic circuits is used to reduce the power consumption in nomadic devices. Power-aware multipliers with configurable precision are used to trade-off the image-rejection-ratio (IRR) performance with power consumption. Results of the simulation case studies demonstrate that the IRR performance of the power-aware system is comparable to that of the normal implementation albeit degraded slightly, but well within the acceptable limits.

Miniaturised sharp rejection bandpass filter with reconfigurable bandwidth for UWB applications

A novel, compact and highly selective microstrip bandpass filter with bandwidth reconfigurability for ultra-wideband (UWB) applications is presented. The proposed design uses stepped impedance resonator (SIR) for realization of bandpass filter (BPF) and employs a single varactor diode (BB135-NXP) for the purpose of reconfiguring bandwidth. Additionally, to improve the selectivity between passband edges, a cross-coupling between I/O feed lines is introduced which generated pairs of attenuation poles at each side of the passband. Measurements on a fabricated reconfigurable filter confirm the accuracy of the design procedure. Measured responses show good agreement with simulation. The proposed filter is able to achieve significant size reduction (8.5 mm × 7.1 mm excluding the feeding ports) as compared to the conventional bandpass filters with reconfigurable bandwidth.