Combustion and operating characteristics of spark-ignition engines

The spark-ignition engine turbulent flame propagation process was investigated. Then, using a spark-ignition engine cycle simulation and combustion model, the impact of turbocharging and heat transfer variations or engine power, efficiency, and NO sub x emissions was examined

Piece Rates and Workplace Injury: Does Survey Evidence Support Adam Smith?

While piece rates are routinely associated with greater productivity and higher wages, they may also generate unanticipated effects. This paper uses cross-country European data to provide among the first broad survey evidence of a strong link between piece rates and workplace injury. Despite unusually good controls for workplace hazards, job characteristics and worker effort, workers on piece rates suffer a large 5 percentage point greater likelihood of injury. As injury rates are typically not controlled for when estimating the premium to piece rates, this raises the specter that a portion of the return to piece rates reflects a compensating wage differential for risk of injury

Separate processing of texture and form in the ventral stream : evidence from fMRI and visual agnosia.

Real-life visual object recognition requires the processing of more than just geometric (shape, size, and orientation) properties. Surface properties such as color and texture are equally important, particularly for providing information about the material properties of objects. Recent neuroimaging research suggests that geometric and surface properties are dealt with separately, within the lateral occipital cortex (LOC) and the collateral sulcus (CoS), respectively. Here we compared objects that either differed in aspect ratio or in surface texture only, keeping all other visual properties constant. Results on brain-intact participants confirmed that surface texture activates an area in the posterior CoS, quite distinct from the area activated by shape within LOC. We also tested two patients with visual object agnosia, one of whom (DF) performed well on the texture task but at chance on the shape task, while the other (MS) showed the converse pattern. This behavioral double dissociation was matched by a parallel neuroimaging dissociation, with activation in CoS but not LOC in patient DF, and activation in LOC but not CoS in patient MS. These data provide presumptive evidence that the areas respectively activated by shape and texture play a causally necessary role in the perceptual discrimination of these features

Vortices and the entrainment transition in the 2D Kuramoto model

We study synchronization in the two-dimensional lattice of coupled phase oscillators with random intrinsic frequencies. When the coupling $K$ is larger than a threshold $K_E$, there is a macroscopic cluster of frequency-synchronized oscillators. We explain why the macroscopic cluster disappears at $K_E$. We view the system in terms of vortices, since cluster boundaries are delineated by the motion of these topological defects. In the entrained phase ($K>K_E$), vortices move in fixed paths around clusters, while in the unentrained phase ($K<K_E$), vortices sometimes wander off. These deviant vortices are responsible for the disappearance of the macroscopic cluster. The regularity of vortex motion is determined by whether clusters behave as single effective oscillators. The unentrained phase is also characterized by time-dependent cluster structure and the presence of chaos. Thus, the entrainment transition is actually an order-chaos transition. We present an analytical argument for the scaling $K_E\sim K_L$ for small lattices, where $K_L$ is the threshold for phase-locking. By also deriving the scaling $K_L\sim\log N$, we thus show that $K_E\sim\log N$ for small $N$, in agreement with numerics. In addition, we show how to use the linearized model to predict where vortices are generated.Comment: 11 pages, 8 figure

The Importance of Sex and the Meaning of Sex and Sexual Pleasure for Men Aged 60 and Older Who Engage in Heterosexual Relationships: Findings from a Qualitative Interview Study

That many older individuals continue to engage in various forms of sexual expression well into later life is now well established in the literature. To date, however, only a small body of qualitative research has examined older men’s experiences and understandings of sex in later life. Likewise, the ways in which older men’s discussions on sex may be used as an avenue for “doing” masculinity remain underexplored. Older men are particularly interesting in this regard, as they inhabit an increasingly subordinated position in relation to hegemonic masculine ideals because of their age. To what extent might this limit or, alternatively, open up the possibilities for sexual expression and subjectivity in later life? Drawing on a subset of findings from Sex, Age, and Me: A National Study with Australian Women and Men Aged 60 and Older, data from qualitative interviews with 27 Australian men were explored in this article. The first Australian study of its kind, we argue that older men who engage in heterosexual relationships draw on a diverse and complex array of discursive positions regarding sex, relationships, and masculinity in making sense of their experiences of sex in later life. Older men are a heterogeneous group, and their experiences and understandings of sex do not simplistically follow “decline” or “success” narratives of aging. The findings of this research build upon and extend emerging research illustrating the centrality of intimacy to older men’s sexual lives, while simultaneously highlighting the ways in which the body and discursive constructions of sex intersect to shape older men’s sexual subjectivities

Existential Contextuality and the Models of Meyer, Kent and Clifton

It is shown that the models recently proposed by Meyer, Kent and Clifton (MKC) exhibit a novel kind of contextuality, which we term existential contextuality. In this phenomenon it is not simply the pre-existing value but the actual existence of an observable which is context dependent. This result confirms the point made elsewhere, that the MKC models do not, as the authors claim, ``nullify'' the Kochen-Specker theorem. It may also be of some independent interest.Comment: Revtex, 7 pages, 1 figure. Replaced with published versio

High-velocity OH megamasers in IRAS 20100-4156: Evidence for a Supermassive Black Hole

We report the discovery of new, high-velocity narrow-line components of the OH megamaser in IRAS 20100-4156. Results from the Australian Square Kilometre Array Pathfinder (ASKAP)'s Boolardy Engineering Test Array (BETA) and the Australia Telescope Compact Array (ATCA) provide two independent measurements of the OH megamaser spectrum. We found evidence for OH megamaser clumps at $-$409 and $-$562 km/s (blue-shifted) from the systemic velocity of the galaxy, in addition to the lines previously known. The presence of such high velocities in the molecular emission from IRAS 20100$-$4156 could be explained by a ~50 pc molecular ring enclosing an approximately 3.8 billion solar mass black hole. We also discuss two alternatives, i.e. that the narrow-line masers are dynamically coupled to the wind driven by the active galactic nucleus or they are associated with two separate galactic nuclei. The comparison between the BETA and ATCA spectra provides another scientific verification of ASKAP's BETA. Our data, combined with previous measurements of the source enabled us to study the variability of the source over a twenty-six year period. The flux density of the brightest OH maser components has reduced by more than a factor of two between 1988 and 2015, whereas a secondary narrow-line component has more than doubled in the same time. Plans for high-resolution VLBI follow-up of this source are discussed, as are prospects for discovering new OH megamasers during the ASKAP early science program.Comment: Accepted to MNRAS. Seven pages, three figure

Self-reported testing and treatment histories among older Australian men and women who may be at risk of a sexually transmissible infection

Background: Rates of sexually transmissible infections (STIs) are increasing among older adults in many countries. Little is known about the testing and treatment histories of these populations. Correlates of testing in the past 5 years among older adults who may be at risk of a STI were examined. Methods: A cross-sectional survey of 2137 Australians aged 60+ years that involved questions on STIs and STI testing was conducted in 2015. To help inform potential education campaigns, analyses focused on those who may have been at risk of a STI (n = 805, 38%). Results: Less than one in three reported a STI test in the past 5 years (n = 241, 30%) while 6% (n = 51) reported a STI diagnosis. Those diagnosed typically received treatment from a family doctor or general practitioner. Among men, lower testing rates were associated with older age, identifying as heterosexual, lower educational attainment, not using online dating and reporting one partner in the past 5 years. For women, lower rates of testing were found among those who did not use a condom at their most recent sexual encounter and those with one partner in the past 5 years. Conclusions: STI testing rates were low. This study indicates that consideration should be given to the way targeted education campaigns are formulated, such as emphasising the importance of STI testing to older people who are at risk, as well as encouraging healthcare professionals to discuss sexual health with their older patients

Safer sex in later life: Qualitative interviews with older Australians on their understandings and practices of safer sex

Rates of sexually transmitted infections (STIs) are increasing in older cohorts in Western countries such as Australia, the U.K. and the U.S., suggesting a need to examine the safer sex knowledge and practices of older people. This article presents findings from 53 qualitative interviews from the study “Sex, Age & Me: a National Study of Sex and Relationships Among Australians aged 60+.” Participants were recruited through an online national survey. We consider how participants understood “safer sex,” the importance of safer sex to them, the safer sex practices they used (and the contexts in which they used them), and the barriers to using safer sex. Older adults had diverse understandings, knowledge, and use of safer sex practices, although participants tended to focus most strongly on condom use. Having safer sex was strongly mediated by relationship context, trust, perceived risk of contracting an STI, concern for personal health, and stigma. Common barriers to safer sex included erectile difficulties, embarrassment, stigma, reduced pleasure, and the lack of a safer sex culture among older people. The data presented has important implications for sexual health policy, practice, and education and health promotion campaigns aimed at improving the sexual health and wellbeing of older cohorts

FRB 20121102A: images of the bursts and the varying radio counterpart

As more Fast Radio Bursts (FRBs) are being localised, we are learning that some fraction have persistent radio sources (PRSs). Such a discovery motivates an improvement in our understanding of the nature of those counterparts, the relation to the bursts themselves and why only some FRBs have PRSs. We report on observations made of FRB 20121102A with the MeerKAT radio telescope. Across five epochs, we detect the PRS associated with FRB 20121102A. Our observations are split into a cluster of four epochs (MJD 58732 - 58764) and a separate single epoch about 1000days later. The measured flux density is constant across the first four observations but then decays by more than one-third in the final observation. Our observations on MJD 58736 coincided with the detections of 11 bursts from FRB 20121102A by the MeerTRAP backend, seven of which we detected in the image plane. We discuss the importance of image plane detections when considering the commensal transient searches being performed with MeerKAT and other radio facilities. We find that MeerKAT is so sensitive that within a two-second image, we can detect any FRB with a flux density above 2.4mJy at 1.3GHz and so could localise every FRB that has been detected by CHIME to date.Comment: Accepted in MNRA