Chemical tuning of the interlayer magnetic coupling in TlCo2Se2-xSx

The system TlCo2Se2-xSx has been thoroughly investigated by neutron powder diffraction and SQUID magnetometry. TlCo2Se2-xSx is a layered tetragonal structure containing atomic cobalt layers separated by a distance of 6.4 angstrom in the sulphide and 6.8 angstrom in the selenide. The solid solubility of isovalent selenium and sulphur atoms in the structure makes it possible to continuously vary the interlayer distance and thereby tune the magnetic coupling between the Co-layers. At low temperatures, the Co-atoms are ferromagnetically ordered within the layers and magnetic moments lie in the ab-plane. However, these Co-moments form a helical magnetic structure that prevails for 0 <= x <= 1.5 with a gradual decrease of the angle between adjacent Co-layers from 122 degrees to 39 degrees. For x >= 1.75, a collinear ferromagnetic structure is stable. The relationship between the coupling angle and the Co-interlayer separation shows an almost linear behaviour. The helical phase contains no net spontaneous magnetic moment up to TlCo2SeS, where a small net magnetic moment appears that increases until the ferromagnetic structure is found for 1.75 <= x <= 2.0. (C) 2005 Elsevier B.V. All rights reserved.

Actively Tuned Plasmons on Elastomerically Driven Au Nanoparticle Dimers

We demonstrate a novel way to actively tune surface plasmons by fabricating plasmonic nanostructures on stretchable elastomeric films. This allows reversible modification of the metal geometry on the nanometer scale. Using 100 nm scale Au nanoparticle dimers whose spacing is stretch-tuned reveals radically different spectral tuning than previously reported for sub-10-nm nanoparticles, but which can be explained by a revised interpretation of existing models. Tuning plasmons in this way offers a much more robust way than lithography to interrogate the physics of localized plasmons and has applications in optimized surface-enhanced luminescence and Raman scattering.

Stretch-induced plasmonic anisotropy of self-assembled gold nanoparticle mats

Close-packed monolayers of 20 nm Au nanoparticles are self-assembled at hexane/water interfaces and transferred to elastic substrates. Stretching the resulting nanoparticle mats provides active and reversible tuning of their plasmonic properties, with a clear polarization dependance. Both uniaxial and biaxial strains induce strong blue shifts in the plasmonic resonances. This matches theoretical simulations and indicates that plasmonic coupling at nanometer scale distances is responsible for the observed spectral tuning. Such stretch-tunable metal nanoparticle mats can be exploited for the development of optical devices, such as flexible colour filters and molecular sensors. (C) 2012 American Institute of Physics. [doi:10.1063/1.3683535]

Transpupillary thermotherapy for choroidal melanoma:Tumor control and visual results in 100 consecutive cases

Objective: The authors evaluated the results of primary transpupillary thermotherapy for choroidal melanoma in 100 cases. Design: Prospective nonrandomized analysis of treatment method. Participants: One hundred patients with choroidal melanoma were studied. Main Outcome Measures: Tumor response, ocular side effects, and visual results. Results: Of 100 consecutive patients with choroidal melanoma treated with transpupillary thermotherapy, the mean tumor basal diameter was 7.1 mm and tumor thickness was 2.8 mm. The tumor margin touched the optic disc in 34 eyes (34%) and was beneath the fovea in 42 eyes (42%). Documented growth was present in 64 eyes (64%), and known clinical risks for growth were present in all of the remaining 36 eyes (36%), with an average of 4 of 5 statistical risk factors for growth per tumor. After a mean of three treatment sessions and 14 months of follow-up, the mean tumor thickness was reduced to 1.4 mm. Treatment was successful in 94 eyes (94%) and failed in 6 eyes (6%). Three patients with amelanotic tumors showed no initial response to thermotherapy, but subsequent intravenous indocyanine green administration during thermotherapy resulted in improved heat absorption and tumor regression to a flat scar. The six eyes classified as treatment failures included four eyes with tumors that showed partial or no response to thermotherapy, thus requiring plaque radiotherapy or enucleation, and two eyes with recurrence, subsequently controlled with additional thermotherapy. After treatment, the visual acuity was the same (within 1 line) or better than the pretreatment visual acuity in 58 eyes (58%) and worse in 42 eyes (42%). The main reasons for poorer vision included treatment through the foveola for subfoveal tumor (25 eyes), retinal traction (10 eyes), retinal vascular obstruction (5 eyes), optic disc edema (1 eye), and unrelated ocular ischemia (1 eye). Temporal location (versus nasal and superior, P = 0.02) and greater distance from the optic disc (P = 0.04) were risks for retinal traction. Conclusions: Transpupillary thermotherapy may be an effective treatment for small posterior choroidal melanoma, especially those near the optic disc and fovea. Despite satisfactory local tumor control, ocular side effects can result in decreased vision. Longer follow- up will be necessary to assess the impact of thermotherapy on ultimate local tumor control and metastatic disease.

The Polish Competition Authority Submits a Draft Amendment to the Polish Competition Act: Revolution or Fine-Tuning?

This piece highlights and offers a brief analysis of the most important of the
proposed changes to Polish competition law. The draft proposal envisages introduction of, inter alia, financial penalties for individuals, two-stage merger review process, important changes to the leniency program (including introduction of leniency plus), as well as such new tools as remedies and settlements.

SiGe V Band Wide Tuning-Range VCO and Frequency Divider for Phase Locked Loop

A V-band wide tuning-range VCO and high frequency divide-by-8 frequency divider using Infineon 0.35 µm SiGe HBT process are presented in this paper. An LC impedance peaking technique is introduced in the Miller divider to increase the sensitivity and operation frequency range of the frequency divider. Two static frequency dividers implemented using current mode logic are used to realize dividing by 4 in the circuit. The wide tuning range VCO operates from 51.9 to 64.1 GHz i.e. 20.3% frequency tuning range. The measured phase noise at the frequency divider output stage is around -98.5 dBc at 1 MHz. The circuit consumes 200mW and operates from a 3.5Vdc supply, and occupies 0.6×0.8 mm2 die area.

Tuning non-Markovianity by spin-dynamics control

We study the interplay between forgetful and memory-keeping evolution enforced on a two-level system by a multi-spin environment whose elements are coupled to local bosonic baths. Contrarily to the expectation that any non-Markovian effect would be buried by the forgetful mechanism induced by the spin-bath coupling, one can actually induce a full Markovian-to-non-Markovian transition of the two-level system's dynamics, controllable by parameters such as the mismatch between the energy of the two-level system and of the spin environment. For a symmetric coupling, the amount of non-Markovianity surprisingly grows with the number of decoherence channels. DOI: 10.1103/PhysRevA.87.022317

Identification of 100 fundamental ecological questions

Fundamental ecological research is both intrinsically interesting and provides the basic knowledge required to answer applied questions of importance to the management of the natural world. The 100th anniversary of the British Ecological Society in 2013 is an opportune moment to reflect on the current status of ecology as a science and look forward to high-light priorities for future work. To do this, we identified 100 important questions of fundamental importance in pure ecology. We elicited questions from ecologists working across a wide range of systems and disciplines. The 754 questions submitted (listed in the online appendix) from 388 participants were narrowed down to the final 100 through a process of discussion, rewording and repeated rounds of voting. This was done during a two-day workshop and thereafter. The questions reflect many of the important current conceptual and technical pre-occupations of ecology. For example, many questions concerned the dynamics of environmental change and complex ecosystem interactions, as well as the interaction between ecology and evolution. The questions reveal a dynamic science with novel subfields emerging. For example, a group of questions was dedicated to disease and micro-organisms and another on human impacts and global change reflecting the emergence of new subdisciplines that would not have been foreseen a few decades ago. The list also contained a number of questions that have perplexed ecologists for decades and are still seen as crucial to answer, such as the link between population dynamics and life-history evolution. Synthesis. These 100 questions identified reflect the state of ecology today. Using them as an agenda for further research would lead to a substantial enhancement in understanding of the discipline, with practical relevance for the conservation of biodiversity and ecosystem function. © 2013 The Authors. Journal of Ecology © 2013 British Ecological Society.

Job strain and the risk of severe asthma exacerbations: A meta-analysis of individual-participant data from 100 000 European men and women

Background: Many patients and healthcare professionals believe that work-related psychosocial stress, such as job strain, can make asthma worse, but this is not corroborated by empirical evidence. We investigated the associations between job strain and the incidence of severe asthma exacerbations in working-age European men and women. Methods: We analysed individual-level data, collected between 1985 and 2010, from 102 175 working-age men and women in 11 prospective European studies. Job strain (a combination of high demands and low control at work) was self-reported at baseline. Incident severe asthma exacerbations were ascertained from national hospitalization and death registries. Associations between job strain and asthma exacerbations were modelled using Cox regression and the study-specific findings combined using random-effects meta-analyses. Results: During a median follow-up of 10 years, 1 109 individuals experienced a severe asthma exacerbation (430 with asthma as the primary diagnostic code). In the age- and sex-adjusted analyses, job strain was associated with an increased risk of severe asthma exacerbations defined using the primary diagnostic code (hazard ratio, HR: 1.27, 95% confidence interval, CI: 1.00, 1.61). This association attenuated towards the null after adjustment for potential confounders (HR: 1.22, 95% CI: 0.96, 1.55). No association was observed in the analyses with asthma defined using any diagnostic code (HR: 1.01, 95% CI: 0.86, 1.19). Conclusions: Our findings suggest that job strain is probably not an important risk factor for severe asthma exacerbations leading to hospitalization or death.

Concordance between digital pathology and light microscopy in general surgical pathology: A pilot study of 100 cases

Aim (1)
A pilot study to determine the accuracy of interpretation of whole slide digital images in a broad range of general histopathology cases of graded complexity. (2) To survey the participating histopathologists with regard to acceptability of digital pathology.

Materials and methods
Glass slides of 100 biopsies and minor resections were digitally scanned in their entirety, producing digital slides. These cases had been diagnosed by light microscopy at least 1 year previously and were subsequently reassessed by the original reporting pathologist (who was blinded to their original diagnosis) using digital pathology. The digital pathology-based diagnosis was compared with the original glass slide diagnosis and classified as concordant, slightly discordant (without clinical consequence) or discordant. The participants were surveyed at the end of the study.

Results
There was concordance between the original light microscopy diagnosis and digital pathology-based diagnosis in 95 of the 100 cases while the remaining 5 cases showed only slight discordance (with no clinical consequence). None of the cases were categorised as discordant. Participants had mixed experiences using digital pathology technology.

Conclusions
In the broad range of cases we examined, digital pathology is a safe and viable method of making a primary histopathological diagnosis.

System level DSP synthesis using voltage overscaling, unequal error protection & adaptive quality tuning

In this paper, we propose a system level design approach considering voltage over-scaling (VOS) that achieves error resiliency using unequal error protection of different computation elements, while incurring minor quality degradation. Depending on user specifications and severity of process variations/channel noise, the degree of VOS in each block of the system is adaptively tuned to ensure minimum system power while providing "just-the-right" amount of quality and robustness. This is achieved, by taking into consideration system level interactions and ensuring that under any change of operating conditions only the "lesscrucial" computations, that contribute less to block/system output quality, are affected. The design methodology applied to a DCT/IDCT system shows large power benefits (up to 69%) at reasonable image quality while tolerating errors induced by varying operating conditions (VOS, process variations, channel noise). Interestingly, the proposed IDCT scheme conceals channel noise at scaled voltages. ©2009 IEEE.

Significance Driven Computation: A Voltage-Scalable, Variation-Aware, Quality-Tuning Motion Estimator

In this paper we present a design methodology for algorithm/architecture co-design of a voltage-scalable, process variation aware motion estimator based on significance driven computation. The fundamental premise of our approach lies in the fact that all computations are not equally significant in shaping the output response of video systems. We use a statistical technique to intelligently identify these significant/not-so-significant computations at the algorithmic level and subsequently change the underlying architecture such that the significant computations are computed in an error free manner under voltage over-scaling. Furthermore, our design includes an adaptive quality compensation (AQC) block which "tunes" the algorithm and architecture depending on the magnitude of voltage over-scaling and severity of process variations. Simulation results show average power savings of similar to 33% for the proposed architecture when compared to conventional implementation in the 90 nm CMOS technology. The maximum output quality loss in terms of Peak Signal to Noise Ratio (PSNR) was similar to 1 dB without incurring any throughput penalty.