New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant

Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here we present the first clear evidence for efficient collisionless electron heating at the reverse shock of Tycho's supernova remnant (SNR), revealed by Fe-K diagnostics using high-quality X-ray data obtained by the Suzaku satellite. We detect K-beta (3p->1s) fluorescence emission from low-ionization Fe ejecta excited by energetic thermal electrons at the reverse shock front, which peaks at a smaller radius than Fe K-alpha (2p->1s) emission dominated by a relatively highly-ionized component. Comparison with our hydrodynamical simulations implies instantaneous electron heating to a temperature 1000 times higher than expected from Coulomb collisions alone. The unique environment of the reverse shock, which is propagating with a high Mach number into rarefied ejecta with a low magnetic field strength, puts strong constraints on the physical mechanism responsible for this heating, and favors a cross-shock potential created by charge deflection at the shock front. Our sensitive observation also reveals that the reverse shock radius of this SNR is about 10% smaller than the previous measurement using the Fe K-alpha morphology from the Chandra observations. Since strong Fe K-beta fluorescence is expected only from low-ionization plasma where Fe ions still have many 3p electrons, this feature is key to diagnosing the plasma state and distribution of the immediate postshock ejecta in a young SNR.Comment: 7 pages, 9 figures, resubmitted to ApJ with minor changes following the referee repor

A Super-Solar Metallicity for the Progenitor of Kepler's Supernova

We have performed deep X-ray observations of the remnant of Kepler's supernova (SN 1604) as a Key Project of the Suzaku Observatory. Our main goal is to detect secondary Fe-peak elements in the SN ejecta to gain insights into the Type Ia supernova explosion mechanism and the nature of the progenitor. Here we report our initial results. We made a conclusive detection of X-ray emission lines from highly ionized Mn, Cr, and Ni as well as Fe. The observed Mn-to-Cr line flux ratio is ~0.60, ~30% larger than that measured in Tycho's remnant. We estimate a Mn-to-Cr mass ratio of ~0.77, which is strongly suggestive of a large neutron excess in the progenitor star before the onset of the thermonuclear runaway. The observed Ni-to-Fe line flux ratio (~0.03) corresponds to a mass ratio of ~0.06, which is generally consistent with the products of explosive Si-burning regime in Type Ia explosion models, and rules out contamination from the products of neutron-rich nuclear statistical equilibrium in the shocked ejecta. Together with the previously suggested luminous nature of the explosion, these mass ratios provide strong evidence for a super-solar metallicity in the SN progenitor (~3 Z_sun). Kepler's supernova was likely the thermonuclear explosion of a white dwarf formed in the recent past that must have exploded through a relatively prompt channel.Comment: Total 12 pages including 2 tables and 2 color figures. Accepted by ApJ

Infected “Mycotic” Aneurysm of the Common Carotid Artery—A Differential Diagnosis to Tumor of the Neck

Introduction: Infected “mycotic” Aneurysm (IA) of the extracranial carotid artery is a rare condition that can be fatal if mistaken for other pathology. An 83-year-old man presented with a mass on the neck initially suspected malignant. Weeks later it grew rapidly and was found to be an IA, thus requiring acute surgery. Via this case report, we discuss diagnostics and approach when diagnosing masses in relation to vessels of the neck not readily explained.Case Report: After diagnostic imaging and clinical assessment an unknown primary tumor of the neck was suspected. Fine needle aspiration was inconclusive. The patient did not present with any signs of infection or neurological symptoms—only discomfort and pain. Approximately two weeks later, the mass grew and the patient became dysphagic, febrile, and confused. Computed tomography angiography revealed an IA of the right common carotid artery. The patient underwent acute surgery consisting of ligation of the internal and external carotid arteries and resection of the internal jugular vein. The pathogen found was E. coli, supposedly from the bladder after surgical intervention due to polyposis.Conclusion: IA is a very rare entity and can have many etiologies. Since it can be fatal, it is necessary to keep IA in mind when diagnosing masses in relation to vessels of the neck. As shown in this case of a E. coli-induced IA, patients can present with atypical symptoms, on diagnostic imaging it can be mistaken for other pathology, and pathogenesis can be unclear

Non-Random Phases in Non-Trivial Topologies

We present a new technique for constraining the topology of the universe. The method exploits the existence of correlations in the phases of the spherical harmonic coefficients of the CMB temperature pattern associated with matched pairs of circles seen in the sky in universes with non-trivial topology. The method is computationally faster than all other statistics developed to hunt for these matched circles. We applied the method to a range of simulations with topologies of various forms and on different scales. A characteristic form of phase correlation is found in the simulations. We also applied the method to preliminary CMB maps derived from WMAP, but the separation of topological effects from, e.g., foregrounds is not straightforward.Comment: 5 pages, accepted for publication in MNRA

Cross-correlating Carbon Monoxide Line-intensity Maps with Spectroscopic and Photometric Galaxy Surveys

Line-intensity mapping (LIM or IM) is an emerging field of observational work, with strong potential to fit into a larger effort to probe large-scale structure and small-scale astrophysical phenomena using multiple complementary tracers. Taking full advantage of such complementarity means, in part, undertaking line-intensity surveys with galaxy surveys in mind. We consider the potential for detection of a cross-correlation signal between COMAP and blind surveys based on photometric redshifts (as in COSMOS) or based on spectroscopic data (as with the HETDEX survey of Lyman-$\alpha$ emitters). We find that obtaining $\sigma_z/(1+z)\lesssim0.003$ accuracy in redshifts and $\gtrsim10^{-4}$ sources per Mpc$^3$ with spectroscopic redshift determination should enable a CO-galaxy cross spectrum detection significance at least twice that of the CO auto spectrum. Either a future targeted spectroscopic survey or a blind survey like HETDEX may be able to meet both of these requirements.Comment: 19 pages + appendix (31 pages total), 16 figures, 6 tables; accepted for publication in Ap

Asking the right questions in adaptation research and practice : Seeing beyond climate impacts in rural Nepal

Adaptation research and practice too often overlooks the wider social context within which climate change is experienced. Mainstream approaches frame adaptation problems in terms of the consequences that flow from biophysical impacts and as a result, we argue, ask the wrong questions. A complementary approach gaining ground in the field, foregrounding the social, economic and political context, reveals differentiation in adaptation need, and how climate impacts interconnect with wider processes of change. In this paper, we illustrate how this kind of approach frames a different set of questions about adaptation using the case of Nepal. Drawing on fieldwork and a review of literature, we contrast the questions that emerge from adaptation research and practice that take climate risk as a starting point with the questions that emerge from examination of contemporary rural livelihoods. We find that while adaptation efforts are often centred around securing agricultural production and are predicated on climate risk management, rural livelihoods are caught in a wider process of transformation. The numbers of people involved in farming are declining, and households are experiencing the effects of rising education, abandonment of rural land, increasing wages, burgeoning mechanisation, and high levels of migration into the global labour market. We find the epistemological framing of adaptation too narrow to account for these changes, as it understands the experiences of rural communities through the lens of climate risk. We propose that rather than seeking to integrate local understandings into a fixed, impacts-orientated epistemology, it is necessary to premise adaptation on an epistemology capable of exploring how change occurs. Asking the right questions thus means opening up adaptation by asking: ‘what are the most significant changes taking place in people's lives?’ along with the more standard: ‘what are the impacts of climate change?’ Viewing adaptation as occurring between and within these two perspectives has the potential to reveal new vulnerabilities and opportunities for adaptation practice to act upon

Sinonasal B-cell lymphomas:A nationwide cohort study, with an emphasis on the prognosis and the recurrence pattern of primary diffuse large B-cell lymphoma

Lymphomas of the nasal cavity and paranasal sinuses (NPS) are rare. Knowledge on sinonasal B‐cell lymphoma (SNBCL) primarily comes from case series or single‐center studies on small cohorts. We sought to determine the subtype distribution, clinical characteristics, disease behavior, and prognosis on a nationwide scale, with an emphasis on prognostic factors for the most common sinonasal lymphoma, primary sinonasal diffuse large B‐cell lymphoma (PSDLBCL). We collated all data from medical records and national databases on patients registered with SNBCL from 1980 through 2018 in the national pathology registry and collected all tissue samples for validation of diagnosis. We included 205 patients and found 10 different subtypes of lymphoma. Diffuse large B‐cell lymphoma (DLBCL) was the predominant subtype (80%). The incidence of SNBCL was 0.14/100,000 person‐years. The five‐year progression‐free survival (PFS) and overall survival rates for PSDLBCL were 50% and 56%, respectively. For PSDLBCL, Rituximab showed a statistically significant effect (Hazard Ratio 0.22, p < 0.001), whereas consolidative radiotherapy combined with immunochemotherapy was of limited value (PFS, p = 0.93). When treatment failure occurred, DLBCL showed a distinct pattern of recurrence/dissemination to the NPS, skin, breast, central nervous system (CNS), and/or testis. Collectively, DLBCL comprised a clear majority of SNBCLs, although nine other subtypes were represented. Data showed that immunochemotherapy increased survival for PSDLBCL and that the addition of radiotherapy did not benefit patients. Furthermore, treatment failure for sinonasal DLBCL showed a possible common pathogenesis with primary extranodal lymphomas of specific locations (e.g., CNS, skin, breast, and testis)

The prevalence of pain and analgesia use in the Australian population: Findings from the 2011 to 2012 Australian National Health Survey

Background: Opioid analgesic use and associated adverse events have increased over the last 15 years, including in Australia. Whether this is associated with increased chronic pain prevalence in the Australian population is unknown. This study aimed to estimate (1) the prevalence of chronic pain and analgesia use in the Australian population by age and sex; (2) the severity of pain in the population with chronic pain by sex; and (3) the distribution of recent pain severity in those using analgesia by age and sex. Methods: This study used cross-sectional, nationally representative data collected by the Australian Bureau of Statistics 2011 to 2012 National Health Survey. A total of n = 20 426 participants were included with an overall response rate of 84.8%. Weighting procedures were applied to obtain population estimates, confidence intervals, and when testing for statistical significance. Results: The prevalence of chronic and reoccurring pain (over a 6-month period) was 15.4% (2.75 million) for Australians aged ≥15 years. Prevalence increased with age for both sexes. Significantly more females reported moderate-to-very severe pain overall (P < 0.001), and within most age groups. Recent use of opioid analgesia was reported by 12.0% of males and 13.4% of females with chronic pain. Conclusion: Chronic pain and opioid analgesic use are important public health issues in Australia. Study estimates of chronic pain and recent pain were no greater than earlier estimates. The acknowledged increase of opioid use in the literature thus appears consistent with changing treatment and/or prescribing patterns over time. Sex differences regarding pain prevalence, severity, and opioid use were apparent

Application of Neonatologist Performed Echocardiography in the assessment and management of neonatal heart failure unrelated to congenital heart disease

Neonatal heart failure (HF) is a progressive disease caused by cardiovascular and non-cardiovascular abnormalities. The most common cause of neonatal HF is structural congenital heart disease, while neonatal cardiomyopathy represents the most common cause of HF in infants with a structurally normal heart. Neonatal cardiomyopathy is a group of diseases manifesting with various morphological and functional phenotypes that affect the heart muscle and alter cardiac performance at, or soon after birth. The clinical presentation of neonates with cardiomyopathy is varied, as are the possible causes of the condition and the severity of disease presentation. Echocardiography is the selected method of choice for diagnostic evaluation, follow-up and analysis of treatment results for cardiomyopathies in neonates. Advances in neonatal echocardiography now permit a more comprehensive assessment of cardiac performance that could not be previously achieved with conventional imaging. In this review, we discuss the current and emerging echocardiographic techniques that aid in the correct diagnostic and pathophysiological assessment of some of the most common etiologies of HF that occur in neonates with a structurally normal heart and acquired cardiomyopathy and we provide recommendations for using these techniques to optimize the management of neonate with HF

Phase Correlations in Cosmic Microwave Background Temperature Maps

We study the statistical properties of spherical harmonic modes of temperature maps of the cosmic microwave background. Unlike other studies, which focus mainly on properties of the amplitudes of these modes, we look instead at their phases. In particular, we present a simple measure of phase correlation that can be diagnostic of departures from the standard assumption that primordial density fluctuations constitute a statistically homogeneous and isotropic Gaussian random field, which should possess phases that are uniformly random on the unit circle. The method we discuss checks for the uniformity of the distribution of phase angles using a non-parametric descriptor based on the use order statistics, which is known as Kuiper's statistic. The particular advantage of the method we present is that, when coupled to the judicious use of Monte Carlo simulations, it can deliver very interesting results from small data samples. In particular, it is useful for studying the properties of spherical harmonics at low l for which there are only small number of independent values of m and which therefore furnish only a small number of phases for analysis. We apply the method to the COBE-DMR and WMAP sky maps, and find departures from uniformity in both. In the case of WMAP, our results probably reflect Galactic contamination or the known variation of signal-to-noise across the sky rather than primordial non-Gaussianity.Comment: 18 pages, 4 figures, accepted for publication in MNRA