Long-term inhibition of return of attention

During search of the environment, the inhibition of the return (IOR) of attention to already-examined information ensures that the target will ultimately be detected. Until now, inhibition was assumed to support search of information during one processing episode. However, in some situations search may have to be completed long after it was begun. We therefore propose that inhibition can be associated with an episode encoded into memory such that later retrieval reinstates inhibitory processing and encourages examination of new information. In two experiments in which attention was drawn to face stimuli with an exogenous cue, we demonstrated for the first time the existence of long-term IOR. Interestingly, this was the case only for faces in the left visual field, perhaps because more efficient processing of faces in the right hemisphere than the left hemisphere results in richer, more retrievable memory representations.

Performance enhancement of asymmetric filtered 40 Gb/s carrier suppressed return to zero-differential phase shift keying receiver in a 50 GHz grid

The authors present the impact of asymmetric filtering of strong (e.g. 35 GHz) optical filters on the performance of 42.7 Gb/s 67% (carrier suppressed return to zero)-differential phase shift keying systems. The performance is examined (in an amplified spontaneous emission (ASE) noise-limited regime and in the presence of chromatic dispersion) when offsetting the filter at the receiver by substantial amounts via balanced, constructive and destructive single-ended detections. It is found that with a slight offset (vestigial side band) or an offset of almost half of the modulation frequency (single-side band), there is a significant improvement in the calculated 'Q'. © The Institution of Engineering and Technology 2013.

Making Sense of Home and Homeland: Former-Soviet Greeks' Motivations and Strategies for a Transnational Migrant Circuit

Focusing on former-Soviet Greeks' experiences of cross-border movement to Greece, this paper sheds light on the impact of this migration on the social identities of Russian Greeks as a transnational community. It draws on informants’ narratives and ethnographic observations recorded among Greek migrants in their home communities in southern Russia, and shows how their motivation, in their transnational movement, is determined by the ‘push-and-pull’ forces of socio-economic and political transformations in post-Soviet space. In these conditions, Greek identity becomes a resource which facilitates the organisation of transnational migration. The cultural, social and economic differences between the former-Soviet Greek migrants and the native-born population of Greece result in the emergence of a Pontic-Greek cultural identity which emphasises migrants’ connections with the former USSR. The difficulties of economic and cultural adaptation for migrants to Greece are examined in relation to the Russian Greeks' economic strategies within their home communities and their perception of the ‘homeland’ as a constantly contested and relocated social construct.

Investigating the role of capacitive coupling between the operating table and the return electrode of an electrosurgery unit in the modification of the current density distribution within the patients’ body

Background: Electrosurgery units are widely employed in modern surgery. Advances in technology have enhanced the safety of these devices, nevertheless, accidental burns are still regularly reported. This study focuses on possible causes of sacral burns as complication of the use of electrosurgery. Burns are caused by local densifications of the current, but the actual pathway of current within patient's body is unknown. Numerical electromagnetic analysis can help in understanding the issue. Methods: To this aim, an accurate heterogeneous model of human body (including seventy-seven different tissues), electrosurgery electrodes, operating table and mattress was build to resemble a typical surgery condition. The patient lays supine on the mattress with the active electrode placed onto the thorax and the return electrode on his back. Common operating frequencies of electrosurgery units were considered. Finite Difference Time Domain electromagnetic analysis was carried out to compute the spatial distribution of current density within the patient's body. A differential analysis by changing the electrical properties of the operating table from a conductor to an insulator was also performed. Results: Results revealed that distributed capacitive coupling between patient body and the conductive operating table offers an alternative path to the electrosurgery current. The patient's anatomy, the positioning and the different electromagnetic properties of tissues promote a densification of the current at the head and sacral region. In particular, high values of current density were located behind the sacral bone and beneath the skin. This did not occur in the case of non-conductive operating table. Conclusion: Results of the simulation highlight the role played from capacitive couplings between the return electrode and the conductive operating table. The concentration of current density may result in an undesired rise in temperature, originating burns in body region far from the electrodes. This outcome is concordant with the type of surgery-related sacral burns reported in literature. Such burns cannot be immediately detected after surgery, but appear later and can be confused with bedsores. In addition, the dosimetric analysis suggests that reducing the capacity coupling between the return electrode and the operating table can decrease or avoid this problem. © 2013 Bifulco et al.; licensee BioMed Central Ltd.

Simultaneous multichannel carrier-suppressed return-to-zero to non-return-to-zero format conversion using a fiber Bragg grating

A novel multichannel carrier-suppressed return-to-zero (CSRZ) to non-return-to-zero (NRZ) format conversion scheme based on a single custom-designed fiber Bragg grating (FBG) with comb spectra is proposed. The spectral response of each channel is designed according to the algebraic difference between the CSRZ and NRZ spectra outlines. The tailored group delays are introduced to minimize the maximum refractive index modulation. Numerical results show that four-channel 200-GHz-spaced CSRZ signals at 40 Gbits/s can be converted into NRZ signals with high Q-factor and wide-range robustness. It is shown that our proposed FBG is robust to deviations of bandwidth and central wavelength detuning. Another important merit of this scheme is that the pattern effects are efficiently reduced owing to the well-designed spectra response.

Migrant entrepreneurs as cosmopolitan change agents:a Bourdieuan perspective on capital accumulation

Purpose : The aim of this paper is to provide novel insights into how the cosmopolitan mind-set can be fostered at a time of globalization by considering a group of social actors that has received scant attention in the literature on institutional change, notably migrant entrepreneurs. Design/methodology/approach : This is a conceptual study that draws on Bourdieu’s theory of capital to develop a set of testable propositions as to how the economic, cultural, social and symbolic capital endowments of migrant entrepreneurs shape their agency in bringing about cosmopolitan transformation. Findings : Together, migrant entrepreneurs endowed with higher levels of capital may act as institution reformers and promote the cosmopolitan mind-set by influencing the beliefs, incentives and behaviors of those embedded in more entrenched traditional institutions. Research limitations/implications : Our conceptual framework deals with only one of the many agents that may help bring about cosmopolitan change and is particularly well suited to a Western European context. Practical implications This conceptual paper provides a number of testable propositions that can be central to an empirical investigation into how the levels of capital possessed by migrant entrepreneurs affect their engagement in cosmopolitan change. Originality/value : The novelty of this paper lies in the development of a set of propositions that shows how divergent change toward a cosmopolitan vision might be engendered by spatially dispersed actors endowed with varying degrees of economic, cultural, social and symbolic capital.