| 1. |
- Andreoni, I., et al.
(författare)
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Follow Up of GW170817 and Its Electromagnetic Counterpart by Australian-Led Observing Programmes
- 2017
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Ingår i: Publications Astronomical Society of Australia. - : Cambridge University Press (CUP). - 1323-3580 .- 1448-6083. ; 34
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Forskningsöversikt (refereegranskat)abstract
- The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (similar to 2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
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| 2. |
- Hibar, D. P., et al.
(författare)
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Subcortical volumetric abnormalities in bipolar disorder
- 2016
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 21:12, s. 1710-1716
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Tidskriftsartikel (refereegranskat)abstract
- Considerable uncertainty exists about the defining brain changes associated with bipolar disorder (BD). Understanding and quantifying the sources of uncertainty can help generate novel clinical hypotheses about etiology and assist in the development of biomarkers for indexing disease progression and prognosis. Here we were interested in quantifying case-control differences in intracranial volume (ICV) and each of eight subcortical brain measures: nucleus accumbens, amygdala, caudate, hippocampus, globus pallidus, putamen, thalamus, lateral ventricles. In a large study of 1710 BD patients and 2594 healthy controls, we found consistent volumetric reductions in BD patients for mean hippocampus (Cohen's d=-0.232; P=3.50 × 10 -7) and thalamus (d=-0.148; P=4.27 × 10 -3) and enlarged lateral ventricles (d=-0.260; P=3.93 × 10 -5) in patients. No significant effect of age at illness onset was detected. Stratifying patients based on clinical subtype (BD type I or type II) revealed that BDI patients had significantly larger lateral ventricles and smaller hippocampus and amygdala than controls. However, when comparing BDI and BDII patients directly, we did not detect any significant differences in brain volume. This likely represents similar etiology between BD subtype classifications. Exploratory analyses revealed significantly larger thalamic volumes in patients taking lithium compared with patients not taking lithium. We detected no significant differences between BDII patients and controls in the largest such comparison to date. Findings in this study should be interpreted with caution and with careful consideration of the limitations inherent to meta-analyzed neuroimaging comparisons. © 2016 Macmillan Publishers Limited, part of Springer Nature.
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| 5. |
- Bhat, N. D. R., et al.
(författare)
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Observations of Low-frequency Radio Emission from Millisecond Pulsars and Multipath Propagation in the Interstellar Medium
- 2018
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Ingår i: Astrophysical Journal, Supplement Series. - : American Astronomical Society. - 1538-4365 .- 0067-0049. ; 238:1
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Tidskriftsartikel (refereegranskat)abstract
- Studying the gravitational-wave sky with pulsar timing arrays (PTAs) is a key science goal for the Square Kilometre Array (SKA) and its pathfinder telescopes. With current PTAs reaching sub-microsecond timing precision, making accurate measurements of interstellar propagation effects and mitigating them effectively has become increasingly important to realize PTA goals. As these effects are much stronger at longer wavelengths, low-frequency observations are most appealing for characterizing the interstellar medium (ISM) along the sight lines toward PTA pulsars. The Murchison Widefield Array (MWA) and the Engineering Development Array (EDA), which utilizes MWA technologies, present promising opportunities for undertaking such studies, particularly for PTA pulsars located in the southern sky. Such pulsars are also the prime targets for PTA efforts planned with the South African MeerKAT, and eventually with the SKA. In this paper we report on observations of two bright southern millisecond pulsars, PSR J0437-4715 and PSR J2145-0750, made with these facilities; MWA observations sampled multiple frequencies across the 80-250 MHz frequency range, while the EDA provided direct-sampled baseband data to yield a large instantaneous usable bandwidth of similar to 200 MHz. Using these exploratory observations, we investigate various aspects relating to pulsar emission and ISM properties, such as spectral evolution of the mean pulse shape, scintillation as a function of frequency, chromaticity in interstellar dispersion, and flux density spectra at low frequencies. Systematic and regular monitoring observations will help ascertain the role of low-frequency measurements in PTA experiments, while simultaneously providing a detailed characterization of the ISM toward the pulsars, which will be useful in devising optimal observing strategies for future PTA experiments.
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| 6. |
- Skinner, Roderick, et al.
(författare)
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Recommendations for gonadotoxicity surveillance in male childhood, adolescent, and young adult cancer survivors : a report from the International Late Effects of Childhood Cancer Guideline Harmonization Group in collaboration with the PanCareSurFup Consortium
- 2017
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Ingår i: The Lancet Oncology. - 1470-2045 .- 1474-5488. ; 18:2, s. 75-90
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Forskningsöversikt (refereegranskat)abstract
- Treatment with chemotherapy, radiotherapy, or surgery that involves reproductive organs can cause impaired spermatogenesis, testosterone deficiency, and physical sexual dysfunction in male pubertal, adolescent, and young adult cancer survivors. Guidelines for surveillance and management of potential adverse effects could improve cancer survivors' health and quality of life. Surveillance recommendations vary considerably, causing uncertainty about optimum screening practices. This clinical practice guideline recommended by the International Late Effects of Childhood Cancer Guideline Harmonization Group in collaboration with the PanCareSurFup Consortium, developed using evidence-based methodology, critically synthesises surveillance recommendations for gonadotoxicity in male childhood, adolescent, and young adult (CAYA) cancer survivors. The recommendations were developed by an international multidisciplinary panel including 25 experts in relevant medical specialties, using a consistent and transparent process. Recommendations were graded according to the strength of underlying evidence and potential benefit gained by early detection and appropriate management. The aim of the recommendations is to enhance evidence-based care for male CAYA cancer survivors. The guidelines reveal the paucity of high-quality evidence, highlighting the need for further targeted research.
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| 7. |
- Kenney-Lazar, Miles, et al.
(författare)
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Greening rubber? Political ecologies of plantation sustainability in Laos and Myanmar
- 2018
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Ingår i: Geoforum. - : Elsevier BV. - 0016-7185 .- 1872-9398. ; 92, s. 96-105
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Tidskriftsartikel (refereegranskat)abstract
- Over the past decade, the cultivation of rubber trees has expanded rapidly throughout the Mekong region to non-traditional rubber growing areas of Laos and Myanmar. Prompted by rising prices from 1990 to 2010 and government agro-industrialization policies, farmers and investors have rushed to plant the new boom crop. A latex price crash in 2011, however, has made it more challenging for small-scale producers to earn an income, leading to uneven social-ecological transformations and economic consequences. Several proposals have been made to address these challenges by transforming rubber into a more economically, socially, and environmentally sustainable crop. In this paper, which emerged from one such project to investigate the potential for green rubber, we argue that the sustainability of rubber is a challenging and elusive prospect - particularly in resource frontier contexts like Laos and Myanmar. Concepts like sustainability or green production are vague and malleable. They can be imbued with a variety of contradictory meanings, which often do not address the most socially and environmentally problematic aspects of cash crop expansion. Sustainable rubber, if rigorously and specifically defined, would be exceedingly difficult to reach in both countries, due to the ways in which political-economic and governance factors interact with the biophysical and social characteristics of the crop. Instead, we recommend using sustainability as a political tool for highlighting the most harmful socio-environmental impacts of rubber and generating debate concerning the best ways to address these, thus limiting unsustainable practices.
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| 8. |
- Roodakker, Kenney R., et al.
(författare)
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PROX1 is a novel pathway-specific prognostic biomarker for high-grade astrocytomas; results from independent glioblastoma cohorts stratified by age and IDH mutation status
- 2016
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:45, s. 72431-72442
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Tidskriftsartikel (refereegranskat)abstract
- PROX1 is a transcription factor with an essential role in embryonic development and determination of cell fate. In addition, PROX1 has been ascribed suppressive as well as oncogenic roles in several human cancers, including brain tumors. In this study we explored the correlation between PROX1 expression and patient survival in high-grade astrocytomas. For this purpose, we analyzed protein expression in tissue microarrays of tumor samples stratified by patient age and IDH mutation status. We initially screened 86 unselected high-grade astrocytomas, followed by 174 IDH1-R132H1 immunonegative glioblastomas derived from patients aged 60 years and older enrolled in the Nordic phase III trial of elderly patients with newly diagnosed glioblastoma. Representing the younger population of glioblastomas, we studied 80 IDH-wildtype glioblastomas from patients aged 18-60 years. There was no correlation between PROX1 protein and survival for patients with primary glioblastomas included in these cohorts. In contrast, high expression of PROX1 protein predicted shorter survival in the group of patients with IDH-mutant anaplastic astrocytomas and secondary glioblastomas. The prognostic impact of PROX1 in IDH-mutant 1p19q non-codeleted high-grade astrocytomas, as well as the negative findings in primary glioblastomas, was corroborated by gene expression data extracted from the Cancer Genome Atlas. We conclude that PROX1 is a new prognostic biomarker for 1p19q non-codeleted high-grade astrocytomas that have progressed from pre-existing lowgrade tumors and harbor IDH mutations.
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| 9. |
- Roodakker, Kenney Roy, 1989-
(författare)
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Towards new tools for clinical evaluation and visualization of tumor growth in patients with glioma
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Gliomas are derived from glial cells and are the most common type of primary brain tumors in adults. Gliomas are classified by the World Health Organization (WHO) according to their malignancy grade and histological and molecular features. Malignancy grades range from I to IV. WHO grade I tumors are benign tumors, mostly occurring in childhood. High-grade gliomas (WHO grades III and IV) are undifferentiated and fast-growing tumors, with glioblastoma being the most common and malignant form. Patients with glioblastomas have a median survival of only 15 months. Clinical outcomes vary, however, and markers are needed to assist in the decision-making process and management of these patients. PROX1 is a transcription factor critical for embryonic development, with a role in cell cycle control and progenitor cell differentiation. Apart from its role in normal central nervous system development, PROX1 has been ascribed both tumor suppressive and oncogenic roles in several human cancers. The role of PROX1 as a prognostic factor for survival in patients with glioblastomas was the focus of paper I.Gliomas WHO grade II, also called diffuse low-grade gliomas (DLGGs), are well-differentiated tumors that occur mainly in adult life, with a peak incidence at around 30–35 years of age and a median survival of 5–10 years. DLGGs grow continuously at a rate of a few mm per year and have a strong tendency to infiltrate the white matter tracts surrounding the tumor. Eventually these tumors transform into high-grade gliomas, but, as is the case with glioblastomas, there is a large variety of clinical outcomes. For radiological diagnosis, magnetic resonance imaging (MRI) is routinely used, often in combination with advanced MRI. Positron emission tomography with amino acid tracers provides additional diagnostic accuracy. From a histological as well as imaging point of view, DLGGs are heterogeneous tumors. The heterogeneity of DLGGs, in particular the correlation between radiological and histological tumor features, was the focus of paper II & paper III.Seizures are amongst the most common presenting symptoms of patients with gliomas. Seizure semiology in patients with brain tumors and other structural brain lesions is closely related to the anatomical location of the lesion and the involvement of functional networks. A possible dynamic interplay between the anatomical region of seizure onset and connected target areas within the network was the focus of paper IV.
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