Acting while perceiving: assimilation precedes contrast

To explore the nature of specific interactions between concurrent perception and action, participants were asked to move one of their hands in a certain direction while simultaneously observing an independent stimulus motion of a (dis)similar direction. The kinematics of the hand trajectories revealed a form of contrast effect (CE) in that the produced directions were biased away from the perceived directions (“Experiment 1”). Specifically, the endpoints of horizontal movements were lower when having watched an upward as opposed to a downward motion. However, when participants moved under higher speed constraints and were not presented with the stimulus motion prior to initiating their movements, the CE was preceded by an assimilation effect, i.e., movements were biased toward the stimulus motion directions (“Experiment 2”). These findings extend those of related studies by showing that CEs of this type actually correspond to the second phase of a bi-phasic pattern of specific perception–action interference

On interference effects in concurrent perception and action

Recent studies have reported repulsion effects between the perception of visual motion and the concurrent production of hand movements. Two models, based on the notions of common coding and internal forward modeling, have been proposed to account for these phenomena. They predict that the size of the effects in perception and action should be monotonically related and vary with the amount of similarity between what is produced and perceived. These predictions were tested in four experiments in which participants were asked to make hand movements in certain directions while simultaneously encoding the direction of an independent stimulus motion. As expected, perceived directions were repelled by produced directions, and produced directions were repelled by perceived directions. However, contrary to the models, the size of the effects in perception and action did not covary, nor did they depend (as predicted) on the amount of perception–action similarity. We propose that such interactions are mediated by the activation of categorical representations

Photonic-Electronic Ultra-Broadband Signal Processing: Concepts, Devices, and Applications

Combining photonic integrated circuits (PIC) with millimeter-wave electronics opens novel perspectives in generation and detection of ultra-broadband signals with disruptive potential for a wide variety of applications. Here, we will give an overview on our recent progress in the field of ultra-broadband photonic-electronic signal processing, covering device concepts such as silicon plasmonic integration, signal processing concepts such as Kramers-Kronig-based phase reconstruction of THz signals, as well as application demonstrations in the field of high-speed wireless data transmission

Silicon-organic hybrid (SOH) devices and their use in comb-based communication systems

Advanced wavelength-division multiplex-ing (WDM) requires both efficient multi-wavelength light sources to generate optical carriers and highly scalable photonic-electronic interfaces to encode data on these carriers. In this paper, we give an overview on our recent progress regarding silicon-organic hy-brid (SOH) integration and comb-based WDM transmission

Evolution of Linear Absorption and Nonlinear Optical Properties in V-Shaped Ruthenium(II)-Based Chromophores

In this article, we describe a series of complexes with electron-rich cis-{Ru^(II)(NH_3)_4}^(2+) centers coordinated to two pyridyl ligands bearing N-methyl/arylpyridinium electron-acceptor groups. These V-shaped dipolar species are new, extended members of a class of chromophores first reported by us (Coe, B. J. et al. J. Am. Chem. Soc. 2005, 127, 4845−4859). They have been isolated as their PF_6− salts and characterized by using various techniques including ^1H NMR and electronic absorption spectroscopies and cyclic voltammetry. Reversible Ru^(III/II) waves show that the new complexes are potentially redox-switchable chromophores. Single crystal X-ray structures have been obtained for four complex salts; three of these crystallize noncentrosymmetrically, but with the individual molecular dipoles aligned largely antiparallel. Very large molecular first hyperpolarizabilities β have been determined by using hyper-Rayleigh scattering (HRS) with an 800 nm laser and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d → π^* metal-to-ligand charge-transfer (MLCT) and π → π^* intraligand charge-transfer (ILCT) bands. The latter measurements afford total nonresonant β_0 responses as high as ca. 600 × 10^(−30) esu. These pseudo-C_(2v) chromophores show two substantial components of the β tensor, β_(zzz) and β_(zyy), although the relative significance of these varies with the physical method applied. According to HRS, β_(zzz) dominates in all cases, whereas the Stark analyses indicate that β_(zyy) is dominant in the shorter chromophores, but β_(zzz) and β_(zyy) are similar for the extended species. In contrast, finite field calculations predict that β_(zyy) is always the major component. Time-dependent density functional theory calculations predict increasing ILCT character for the nominally MLCT transitions and accompanying blue-shifts of the visible absorptions, as the ligand π-systems are extended. Such unusual behavior has also been observed with related 1D complexes (Coe, B. J. et al. J. Am. Chem. Soc. 2004, 126, 3880−3891)

Supervised versus unsupervised categorization: Two sides of the same coin?

Supervised and unsupervised categorization have been studied in separate research traditions. A handful of studies have attempted to explore a possible convergence between the two. The present research builds on these studies, by comparing the unsupervised categorization results of Pothos et al. (submitted; 2008) with the results from two procedures of supervised categorization. In two experiments, we tested 375 participants with nine different stimulus sets, and examined the relation between ease of learning of a classification, memory for a classification, and spontaneous preference for a classification. After taking into account the role of the number of category labels (clusters) in supervised learning, we found the three variables to be closely associated with each other. Our results provide encouragement for researchers seeking unified theoretical explanations for supervised and unsupervised categorization, but raise a range of challenging theoretical questions

Summary for policymakers

The Working Group III contribution to the IPCC Fifth Assessment Report (WGIII AR5) provides a comprehensive assessment of all relevant options for mitigating climate change through limiting or preventing greenhouse gas emissions, as well as activities that remove them from the atmosphere. It draws on scientific literature accepted for publication prior to 4 October 2013. The WGIII Summary for Policymakers was approved at the Twelfth Session of Working Group III, held in Berlin, Germany, from 7 to 11 April, 2014. During the session, the IPCC plenary also accepted the underlying scientific and technical assessment, which stands at 2000 pages, including more than 700 pages of references

Technical summary

The Working Group III (WGIII) contribution to the IPCC's Fifth Assessment Report (AR5) assesses literature on the scientific, technological, environmental, economic and social aspects of mitigation of climate change. It builds upon the WGIII contribution to the IPCC's Fourth Assessment Report (AR4), the Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) and previous reports and incorporates subsequent new findings and research. Throughout, the focus is on the implications of its findings for policy, without being prescriptive about the particular policies that governments and other important participants in the policy process should adopt. In light of the IPCC's mandate, authors in WGIII were guided by several principles when assembling this assessment: (1) to be explicit about mitigation options, (2) to be explicit about their costs and about their risks and opportunities vis-a-vis other development priorities, (3) and to be explicit about the underlying criteria, concepts, and methods for evaluating alternative policies. This summary offers the main findings of the report