Synaptic Self-Organization of Spatio-Temporal Pattern Selectivity

Spiking model neurons can be set up to respond selectively to specific spatio-temporal spike patterns by optimization of their input weights. It is unknown, however, if existing synaptic plasticity mechanisms can achieve this temporal mode of neuronal coding and computation. Here it is shown that changes of synaptic efficacies which tend to balance excitatory and inhibitory synaptic inputs can make neurons sensitive to particular input spike patterns. Simulations demonstrate that a combination of Hebbian mechanisms, hetero-synaptic plasticity and synaptic scaling is sufficient for self-organizing sensitivity for spatio-temporal spike patterns that repeat in the input. In networks inclusion of hetero-synaptic plasticity leads to specialization and faithful representation of pattern sequences by a group of target neurons. Pattern detection is found to be robust against a range of distortions and noise. Furthermore, the resulting balance of excitatory and inhibitory inputs protects the memory for a specific pattern from being overwritten during ongoing learning when the pattern is not present. These results not only provide an explanation for experimental observations of balanced excitation and inhibition in cortex but also promote the plausibility of precise temporal coding in the brain.

Comparison of continuous and pulsed wave lasers in keyhole welding of stainless-steel to aluminium

A continuous wave (CW) and a nanosecond pulsed wave (PW) lasers were used to join 1-mm thick sheets of SS304L (SS) austenitic stainless-steel to AA5251 (Al) aluminium alloy in an overlap joint configuration. The weld shape (penetration depth and width), intermetallic compounds concentration, weld quality (cracking and porosity) and mechanical strength were correlated with the process energy and compared between each laser temporal mode. Successful CW joints were produced with the SS sheet on top of the Al, but the opposite configuration revealed to be impossible for the range of parameters tested. The PW joints were successful with the Al sheet on top of SS, but all the joints cracked at the interface when the opposite configuration was used. The mechanical tests showed that even though it is possible to achieve higher tensile shear load in CW welds due to the larger bonding area, the tensile shear strength revealed to be almost 5 × higher for PW welds at similar applied energy.

Segmental Variability of Precipitation In The Mahanadi River Basin During 1901-2017

Eigen-based sequential spatial pattern analysis an application of PCA is presented here. The analysis examines the spatial distribution of precipitation over the Mahanadi river basin. The Spatial(S)-mode of sequential spatial pattern analysis with the application of Maximum loading value of rotated retained principal component (also referred to as Maximum loading value approach) to assess a gridded monthly rainfall data of resolution 0.25° x 0.25° having a record length of 117 years (1901-2017). The meteorological records have a sequential spatial field for Spatial and Temporal-mode, which can be used for recognizing the area for precipitation variability and regime. The identified patterns of the different timeslot segments were then analyzed for their dispersions of the annual precipitation observed at different station points using similarities and dissimilar characteristics of inter-cluster and between clusters respectively. Validation of the regionalized pattern for distinctness and a pairwise comparison of CDFs using the Kolmogorov-Smirnov ‘D’ statistic test.

Comparison of Continuous and Pulsed Wave Lasers in Keyhole Welding of Stainless-Steel to Aluminium

A continuous wave (CW) and a nanosecond pulsed wave (PW) lasers were used to join 1 mm thick sheets of SS304L (SS) austenitic stainless-steel to AA5251 (Al) aluminium alloy in an overlap joint configuration. The weld shape (penetration depth and width), intermetallic compounds concentration, weld quality (cracking and porosity) and mechanical strength were correlated with the process energy and compared between each laser temporal mode. Successful CW joints were produced with the SS sheet on top of the Al, but the opposite configuration revealed to be impossible for the range of parameters tested. The PW joints were successful with the Al sheet on top of SS, but all the joints cracked at the interface when the opposite configuration was used. The mechanical tests showed that even though it is possible to achieve higher tensile shear load in CW welds due to the larger bonding area, the load per unit of weld length revealed to be almost 5x higher for PW welds at similar applied energy.

Schizophrenia, Temporality, and Affection

Temporal experience and its radical alteration in schizophrenia have been one of the central objects of investigation in phenomenological psychopathology. Various phenomenologically oriented researchers have argued that the change in the mode of temporal experience present in schizophrenia can foreground its psychotic symptoms of delusion. This paper aims to further the development of such a phenomenological investigation by highlighting a much-neglected aspect of schizophrenic temporal experience, i.e., its non-emotional affective characteristic. In this paper, it denotes the type of an experience wherein an afflicted individual experiences a pervasive pull or attraction coming from the past, present, and future. By employing Husserl’s account of affection, I argue that such an affectively prominent temporal experience is not yet another abnormality that happens to be present in schizophrenia. Instead, it is indicative of the core disturbance that underpins the schizophrenic temporal mode of experience. I identify such a disturbance as ‘affective modification dysfunction’ and employ it as a core concept with which I synthesize and organise heterogeneous components of schizophrenic temporal experience in their conceptual unity. For the sake of clear description, I organise those components into the following categories: 1.) Time Stop 2.) Ante-festum 3.) Déjà vu/vécu and 4.) Time Fragmentation. I conclude by demonstrating how approaching schizophrenic temporal experience from its affective dimension can further help us better understand its pre-psychotic phase known to precipitate schizophrenic primary delusion, i.e., delusional mood.

High-dimensional temporal mode propagation in a turbulent environment

Temporal modes of photonic quantum states, intrinsically possess high dimensional Hilbert spaces, provide a new framework to develop a robust free-space quantum key distribution (QKD) scheme in a maritime environment. We show that the high-dimensional temporal modes can be used to fulfill a persistent communication channel to achieve high photon-efficiency even in severe weather conditions. We identify the parameter regimes that allow for a high-fidelity quantum information transmission. We also examine how the turbulent environment affects fidelity and entanglement degree in various environmental settings.