Response time distribution in a tandem pair of queues with batch processing

Response time density is obtained in a tandem pair of Markovian queues with both batch arrivals and batch departures. The method uses conditional forward and reversed node sojourn times and derives the Laplace transform of the response time probability density function in the case that batch sizes are finite. The result is derived by a generating function method that takes into account that the path is not overtake-free in the sense that the tagged task being tracked is affected by later arrivals at the second queue. A novel aspect of the method is that a vector of generating functions is solved for, rather than a single scalar-valued function, which requires investigation of the singularities of a certain matrix. A recurrence formula is derived to obtain arbitrary moments of response time by differentiation of the Laplace transform at the origin, and these can be computed rapidly by iteration. Numerical results for the first four moments of response time are displayed for some sample networks that have product-form solutions for their equilibrium queue length probabilities, along with the densities themselves by numerical inversion of the Laplace transform. Corresponding approximations are also obtained for (non-product-form) pairs of “raw” batch-queues – with no special arrivals – and validated against regenerative simulation, which indicates good accuracy. The methods are appropriate for modeling bursty internet and cloud traffic and a possible role in energy-saving is considered

Adults can be trained to acquire synesthetic experiences

Synesthesia is a condition where presentation of one perceptual class consistently evokes additional experiences in different perceptual categories. Synesthesia is widely considered a congenital condition, although an alternative view is that it is underpinned by repeated exposure to combined perceptual features at key developmental stages. Here we explore the potential for repeated associative learning to shape and engender synesthetic experiences. Non-synesthetic adult participants engaged in an extensive training regime that involved adaptive memory and reading tasks, designed to reinforce 13 specific letter-color associations. Following training, subjects exhibited a range of standard behavioral and physiological markers for grapheme-color synesthesia; crucially, most also described perceiving color experiences for achromatic letters, inside and outside the lab, where such experiences are usually considered the hallmark of genuine synesthetes. Collectively our results are consistent with developmental accounts of synesthesia and illuminate a previously unsuspected potential for new learning to shape perceptual experience, even in adulthood

Spectral collocation solutions to multiparameter Mathieu's system

Our main aim is the accurate computation of a large number of specified eigenvalues and eigenvectors of Mathieu's system as a multiparameter eigenvalue problem (MEP). The reduced wave equation, for small deflections, is solved directly without approximations introduced by the classical Mathieu functions. We show how for moderate values of the cut-off collocation parameter the QR algorithm and the Arnoldi method may be applied successfully, while for larger values the Jacobi-Davidson method is the method of choice with respect to convergence, accuracy and memory usage

Quantifying polarization across political groups on key policy issues using sentiment analysis

There is growing concern that over the past decade, industrialized democratic nations are becoming increasingly politically polarized. Indeed, elections in the US, UK, France, and Germany have all seen tightly won races, with notable examples including the 2016 Trump vs. Clinton presidential election and the UK's Brexit referendum. However, while there has been much qualitative discussion of polarization on key issues, there are few examples of formal quantitative assessments examining this topic. Therefore, in this paper, we undertake a statistical evaluation of political polarization for representatives elected to the US congress on key policy issues between 2021-2022. The method is based on applying sentiment analysis to Twitter data and developing quantitative analysis for six political groupings defined based on voting records. Two sets of policy groups are explored, including geopolitical policies (e.g., Ukraine-Russia, China, Taiwan, etc.) and domestic policies (e.g., abortion, climate change, LGBTQ, immigration, etc.). We find that out of the twelve policies explored here, gun control was the most politically polarizing, with significant polarization results found for all groups (four of which were P < 0.001). The next most polarizing issues include immigration and border control, fossil fuels, and Ukraine-Russia. Interestingly, the least polarized policy topics were Taiwan, LGBTQ, and the Chinese Communist Party, potentially demonstrating the highest degree of bipartisanship on these issues. The results can be used to guide future policy making, by helping to identify areas of common ground across political groups.Comment: 31 pages, 7 figure

Obstetrical Outcomes of Aboriginal Pregnancies at a Major Urban Hospital

While a number of previous papers have documented the poor general health of Australia's Aboriginal population, relatively few have considered the health of Aborigines living in Australia's urban centres. In this latter instance, Aborigines have access to conventional medical services and they live in a physical environment that does not differ greatly from that experienced by the lower-class white population. Of course, racial, familial and economic differences may continue to influence differentially the perceived accessibility of services to Aborigines and their non-Aboriginal neighbours. This paper compares the pregnancy outcomes of Aboriginal women and non-Aboriginal women living in a major urban centre in Australia. The data indicate that urban Aboriginal women have adverse pregnancy outcomes at one and a half o two times the rate experienced by the non-Aboriginal population. Much of the difference can be attributed to lifestyle variations in the groups being compared

Theory of plasmon reflection by a 1D junction

We present a comprehensive study of the reflection of normally incident plasmon waves from a low-conductivity 1D junction in a 2D conductive sheet. Rigorous analytical results are derived in the limits of wide and narrow junctions. Two types of phenomena determine the reflectance, the cavity resonances within the junction and the capacitive coupling between the leads. The resonances give rise to alternating strong and weak reflection but are vulnerable to plasmonic damping. The capacitive coupling, which is immune to damping, induces a near perfect plasmon reflection in junctions narrower than $1/10$ of the plasmon wavelength. Our results are important for infrared 2D plasmonic circuits utilizing slot antennas, split gates or nanowire gates. They are also relevant for the implementation of nanoscale terahertz detectors, where optimal light absorption coincides with the maximal junction reflectance

Neurophenomenology of induced and natural synaesthesia.

People with synaesthesia have additional perceptual experiences, which are automatically and consistently triggered by specific inducing stimuli. Synaesthesia therefore offers a unique window into the neurocognitive mechanisms underlying conscious perception. A long-standing question in synaesthesia research is whether it is possible to artificially induce non-synaesthetic individuals to have synaesthesia-like experiences. Although synaesthesia is widely considered a congenital condition, increasing evidence points to the potential of a variety of approaches to induce synaesthesia-like experiences, even in adulthood. Here, we summarize a range of methods for artificially inducing synaesthesia-like experiences, comparing the resulting experiences to the key hallmarks of natural synaesthesia which include consistency, automaticity and a lack of 'perceptual presence'. We conclude that a number of aspects of synaesthesia can be artificially induced in non-synaesthetes. These data suggest the involvement of developmental and/or learning components in the acquisition of synaesthesia, and they extend previous reports of perceptual plasticity leading to dramatic changes in perceptual phenomenology in adults. This article is part of a discussion meeting issue 'Bridging senses: novel insights from synaesthesia'

Postnatal Depression - Myth and Reality: Maternal Depression Before and After the Birth of a Child

Background Much has been written about postnatal depression as a clinical condition. There is some evidence to suggest that a substantial proportion of women who give birth experience a depression in the postnatal period. This paper reports the results of a longitudinal study of the mental health of a large sample of women who were in the early stages of pregnancy at entry to the study. Methods Each participant was assessed for symptoms of depression at the first clinic visit (entry to the study), and reassessed at various intervals - at 3-5 days, at 6 months, and again at 5 years after the birth of the child - using the DSSI-D (Delusions-Symptoms-States Inventory). Results Retrospective recall questions indicate that shortly after the birth the majority of women experienced some depressed mood. Of those who experienced depressed mood, the data suggest that the symptoms were not severe, nor did these symptoms generally continue beyond a few weeks. The longitudinal data indicate that levels of depression in our sample are highest either at the firrst clinic visit or at the 5-year follow-up. Rates of depression at the 6-month follow-up are relatively low by comparison. Conclusion While most mothers experience periods of depressed mood after the birth of their baby, these periods are generally of short duration and of lesser intensity than a major depression. Mothers appear to experience increasing levels of symptoms of depression as their child grows up. Many of the "cases" of depression experienced at the 5-year follow-up represent a recurrence of a previous experience of depression