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Christopher J. Russell

Bio: Christopher J. Russell is an academic researcher from University of Southern California. The author has contributed to research in topics: Pulsar & Pulsar timing array. The author has an hindex of 18, co-authored 65 publications receiving 1521 citations. Previous affiliations of Christopher J. Russell include CSIRO Marine and Atmospheric Research & Harvard University.


Papers
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Journal ArticleDOI
TL;DR: Factors that contribute to the immunogenicity of these highly targeted and relatively conserved sequences in HIV that may represent promising vaccine candidates for ethnically heterogeneous populations are identified.
Abstract: Although there is increasing evidence that virus-specific cytotoxic-T-lymphocyte (CTL) responses play an important role in the control of human immunodeficiency virus (HIV) replication in vivo, only scarce CTL data are available for the ethnic populations currently most affected by the epidemic. In this study, we examined the CD8+-T-cell responses in African-American, Caucasian, Hispanic, and Caribbean populations in which clade B virus dominates and analyzed the potential factors influencing immune recognition. Total HIV-specific CD8+-T-cell responses were determined by enzyme-linked immunospot assays in 150 HIV-infected individuals by using a clade B consensus sequence peptide set spanning all HIV proteins. A total of 88% of the 410 tested peptides were recognized, and Nef- and Gag-specific responses dominated the total response for each ethnicity in terms of both breadth and magnitude. Three dominantly targeted regions within these proteins that were recognized by >90% of individuals in each ethnicity were identified. Overall, the total breadth and magnitude of CD8+-T-cell responses correlated with individuals’ CD4 counts but not with viral loads. The frequency of recognition for each peptide was highly correlated with the relative conservation of the peptide sequence, the presence of predicted immunoproteasomal cleavage sites within the C-terminal half of the peptide, and a reduced frequency of amino acids that impair binding of optimal epitopes to the restricting class I molecules. The present study thus identifies factors that contribute to the immunogenicity of these highly targeted and relatively conserved sequences in HIV that may represent promising vaccine candidates for ethnically heterogeneous populations.

292 citations

Journal ArticleDOI
Benetge Perera1, Benetge Perera2, Megan E. DeCesar3, Paul Demorest4, Matthew Kerr5, L. Lentati, David J. Nice3, Stefan Oslowski6, Scott M. Ransom4, Michael Keith1, Zaven Arzoumanian7, Matthew Bailes6, P. T. Baker8, C. G. Bassa9, N. D. R. Bhat10, A. Brazier11, M. Burgay12, Sarah Burke-Spolaor8, Sarah Burke-Spolaor13, R. N. Caballero14, D. J. Champion15, Sourav Chatterjee11, Siyuan Chen, Ismaël Cognard16, Ismaël Cognard17, James M. Cordes11, Kathryn Crowter18, Shi Dai19, Gregory Desvignes20, Gregory Desvignes15, Timothy Dolch21, Robert D. Ferdman22, Elizabeth C. Ferrara23, Elizabeth C. Ferrara7, Emmanuel Fonseca24, Janna Goldstein25, E. Graikou15, Lucas Guillemot17, Lucas Guillemot16, Jeffrey S. Hazboun26, George Hobbs19, H. Hu15, K. Islo27, Gemma H. Janssen28, Gemma H. Janssen9, Ramesh Karuppusamy15, Michael Kramer15, Michael Kramer1, Michael T. Lam8, Kejia Lee14, Kang Liu15, Jing Luo29, Andrew Lyne1, Richard N. Manchester19, J. W. McKee1, J. W. McKee15, Maura McLaughlin8, Chiara M. F. Mingarelli30, Aditya Parthasarathy6, Timothy T. Pennucci31, Delphine Perrodin12, A. Possenti12, A. Possenti32, Daniel J. Reardon6, Christopher J. Russell33, S. A. Sanidas1, Alberto Sesana34, G. Shaifullah9, Ryan Shannon6, X. Siemens35, X. Siemens27, Joseph Simon36, Renée Spiewak6, Ingrid H. Stairs18, Benjamin Stappers1, J. K. Swiggum27, Stephen Taylor37, Stephen Taylor36, Gilles Theureau17, Gilles Theureau16, Gilles Theureau20, Caterina Tiburzi9, Michele Vallisneri36, Alberto Vecchio25, J. B. Wang38, Songbo Zhang38, Lei Zhang19, Lei Zhang38, Weiwei Zhu38, Weiwei Zhu15, Xing-Jiang Zhu39 
TL;DR: In this article, the authors describe the International Pulsar Timing Array second data release, which includes recent pulsar timing data obtained by three regional consortia: the European Pulsars Timing array, the North American Nanohertz Observatory for Gravitational Waves, and the Parkes pulsar timing array, and find that the timing precisions of pulsars are generally improved compared to the previous data release.
Abstract: In this paper, we describe the International Pulsar Timing Array second data release, which includes recent pulsar timing data obtained by three regional consortia: the European Pulsar Timing Array, the North American Nanohertz Observatory for Gravitational Waves, and the Parkes Pulsar Timing Array. We analyse and where possible combine high-precision timing data for 65 millisecond pulsars which are regularly observed by these groups. A basic noise analysis, including the processes which are both correlated and uncorrelated in time, provides noise models and timing ephemerides for the pulsars. We find that the timing precisions of pulsars are generally improved compared to the previous data release, mainly due to the addition of new data in the combination. The main purpose of this work is to create the most up-to-date IPTA data release. These data are publicly available for searches for low-frequency gravitational waves and other pulsar science.

289 citations

Journal ArticleDOI
TL;DR: Sexual orientation continued to account for significant variance in BULIT-R, EAT-26, and BSQ scores, and future research may benefit from exploring aspects of homosexuality that may contribute specifically to risk for disordered eating in men.
Abstract: Objective The current study examined whether homosexuality is a specific risk factor for disordered eating in men. Method Men (64 heterosexual and 58 homosexual) completed the Beck Depression Inventory (BDI), the Rosenberg Self-Esteem Scale (RSE), the Masculinity and Femininity scales of the Bem Sex-Role Inventory (BSRI), the Bulimia Test-Revised (BULIT-R), the Eating Attitudes Test (EAT-26), and the Body Shape Questionnaire (BSQ). Results Homosexual men had more pathological scores on the BDI, RSE, BULIT-R, EAT-26, and BSQ. Additionally, homosexual men reported greater discomfort with sexual orientation. After controlling for differences in depression, self-esteem, and comfort with sexual orientation, sexual orientation continued to account for significant variance in BULIT-R, EAT-26, and BSQ scores. Discussion Future research may benefit from exploring aspects of homosexuality that may contribute specifically to risk for disordered eating in men. © 2002 by Wiley Periodicals, Inc. Int J Eat Disord 31: 300–306, 2002; DOI 10.1002/eat.10036

258 citations

Journal ArticleDOI
TL;DR: In this paper, the Parkes Pulsar Timing Array (PTA) data were used to detect the spatial correlation of the Hellings-downs signature of the gravitational wave background.
Abstract: A nanohertz-frequency stochastic gravitational-wave background can potentially be detected through the precise timing of an array of millisecond pulsars. This background produces low-frequency noise in the pulse arrival times that would have a characteristic spectrum common to all pulsars and a well-defined spatial correlation. Recently the North American Nanohertz Observatory for Gravitational Waves collaboration (NANOGrav) found evidence for the common-spectrum component in their 12.5-year data set. Here we report on a search for the background using the second data release of the Parkes Pulsar Timing Array. If we are forced to choose between the two NANOGrav models $\unicode{x2014}$ one with a common-spectrum process and one without $\unicode{x2014}$ we find strong support for the common-spectrum process. However, in this paper, we consider the possibility that the analysis suffers from model misspecification. In particular, we present simulated data sets that contain noise with distinctive spectra but show strong evidence for a common-spectrum process under the standard assumptions. The Parkes data show no significant evidence for, or against, the spatially correlated Hellings-Downs signature of the gravitational-wave background. Assuming we did observe the process underlying the spatially uncorrelated component of the background, we infer its amplitude to be $A = 2.2^{+0.4}_{-0.3} \times 10^{-15}$ in units of gravitational-wave strain at a frequency of $1\, \text{yr}^{-1}$. Extensions and combinations of existing and new data sets will improve the prospects of identifying spatial correlations that are necessary to claim a detection of the gravitational-wave background.

136 citations

Journal ArticleDOI
TL;DR: 14 yr of public data from the Parkes Pulsar Timing Array is described, an ongoing project that is producing precise measurements of pulse times of arrival from 26 millisecond pulsars using the 64-m Parkes radio telescope with a cadence of approximately 3 weeks in three observing bands.
Abstract: We describe 14 yr of public data from the Parkes Pulsar Timing Array (PPTA), an ongoing project that is producing precise measurements of pulse times of arrival from 26 millisecond pulsars using the 64-m Parkes radio telescope with a cadence of approximately 3 weeks in three observing bands. A comprehensive description of the pulsar observing systems employed at the telescope since 2004 is provided, including the calibration methodology and an analysis of the stability of system components. We attempt to provide full accounting of the reduction from the raw measured Stokes parameters to pulse times of arrival to aid third parties in reproducing our results. This conversion is encapsulated in a processing pipeline designed to track provenance. Our data products include pulse times of arrival for each of the pulsars along with an initial set of pulsar parameters and noise models. The calibrated pulse profiles and timing template profiles are also available. These data represent almost 21 000 h of recorded data spanning over 14 yr. After accounting for processes that induce time-correlated noise, 22 of the pulsars have weighted root-mean-square timing residuals of in at least one radio band. The data should allow end users to quickly undertake their own gravitational wave analyses, for example, without having to understand the intricacies of pulsar polarisation calibration or attain a mastery of radio frequency interference mitigation as is required when analysing raw data files.

110 citations


Cited by
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01 Sep 2008
TL;DR: The Methodology used to Prepare the Guideline Epidemiology Incidence Etiology and Recommendations for Assessing Response to Therapy Suggested Performance Indicators is summarized.
Abstract: Executive Summary Introduction Methodology Used to Prepare the Guideline Epidemiology Incidence Etiology Major Epidemiologic Points Pathogenesis Major Points for Pathogenesis Modifiable Risk Factors Intubation and Mechanical Ventilation Aspiration, Body Position, and Enteral Feeding Modulation of Colonization: Oral Antiseptics and Antibiotics Stress Bleeding Prophylaxis, Transfusion, and Glucose Control Major Points and Recommendations for Modifiable Risk Factors Diagnostic Testing Major Points and Recommendations for Diagnosis Diagnostic Strategies and Approaches Clinical Strategy Bacteriologic Strategy Recommended Diagnostic Strategy Major Points and Recommendations for Comparing Diagnostic Strategies Antibiotic Treatment of Hospital-acquired Pneumonia General Approach Initial Empiric Antibiotic Therapy Appropriate Antibiotic Selection and Adequate Dosing Local Instillation and Aerosolized Antibiotics Combination versus Monotherapy Duration of Therapy Major Points and Recommendations for Optimal Antibiotic Therapy Specific Antibiotic Regimens Antibiotic Heterogeneity and Antibiotic Cycling Response to Therapy Modification of Empiric Antibiotic Regimens Defining the Normal Pattern of Resolution Reasons for Deterioration or Nonresolution Evaluation of the Nonresponding Patient Major Points and Recommendations for Assessing Response to Therapy Suggested Performance Indicators

2,961 citations

01 Jan 2011
TL;DR: The National Institutes of Health asked the Institute of Medicine to assess current knowledge of the health status of lesbian, gay, bisexual, and transgender populations; to identify research gaps and opportunities; and to outline a research agenda to help NIH focus its research in this area.
Abstract: At a time when lesbian, gay, bisexual, and transgender individuals—often referred to under the umbrella acronym LGBT—are becoming more visible in society and more socially acknowledged, clinicians and researchers are faced with incomplete information about their health status. While LGBT populations often are combined as a single entity for research and advocacy purposes, each is a distinct population group with its own specific health needs. Furthermore, the experiences of LGBT individuals are not uniform and are shaped by factors of race, ethnicity, socioeconomic status, geographical location, and age, any of which can have an effect on health-related concerns and needs. While some research about the health of LGBT populations has been conducted, researchers still have a great deal to learn. To help assess the state of the science, the National Institutes of Health (NIH) asked the Institute of Medicine (IOM) to assess current knowledge of the health status of lesbian, gay, bisexual, and transgender populations; to identify research gaps and opportunities; and to outline a research agenda to help NIH focus its research in this area. A committee of experts was convened by the IOM to consider this task, and its findings are presented in its report, The Health of Lesbian, Gay, Bisexual, and Transgender People: Building a Foundation for Better Understanding.

2,200 citations

Journal ArticleDOI
TL;DR: A systematic review and meta-analysis of the prevalence of mental disorder, substance misuse, suicide, suicidal ideation and deliberate self harm in LGB people revealed that lesbian and bisexual women were particularly at risk of substance dependence.
Abstract: Lesbian, gay and bisexual (LGB) people may be at higher risk of mental disorders than heterosexual people. We conducted a systematic review and meta-analysis of the prevalence of mental disorder, substance misuse, suicide, suicidal ideation and deliberate self harm in LGB people. We searched Medline, Embase, PsycInfo, Cinahl, the Cochrane Library Database, the Web of Knowledge, the Applied Social Sciences Index and Abstracts, the International Bibliography of the Social Sciences, Sociological Abstracts, the Campbell Collaboration and grey literature databases for articles published January 1966 to April 2005. We also used Google and Google Scholar and contacted authors where necessary. We searched all terms related to homosexual, lesbian and bisexual people and all terms related to mental disorders, suicide, and deliberate self harm. We included papers on population based studies which contained concurrent heterosexual comparison groups and valid definition of sexual orientation and mental health outcomes. Of 13706 papers identified, 476 were initially selected and 28 (25 studies) met inclusion criteria. Only one study met all our four quality criteria and seven met three of these criteria. Data was extracted on 214,344 heterosexual and 11,971 non heterosexual people. Meta-analyses revealed a two fold excess in suicide attempts in lesbian, gay and bisexual people [pooled risk ratio for lifetime risk 2.47 (CI 1.87, 3.28)]. The risk for depression and anxiety disorders (over a period of 12 months or a lifetime) on meta-analyses were at least 1.5 times higher in lesbian, gay and bisexual people (RR range 1.54–2.58) and alcohol and other substance dependence over 12 months was also 1.5 times higher (RR range 1.51–4.00). Results were similar in both sexes but meta analyses revealed that lesbian and bisexual women were particularly at risk of substance dependence (alcohol 12 months: RR 4.00, CI 2.85, 5.61; drug dependence: RR 3.50, CI 1.87, 6.53; any substance use disorder RR 3.42, CI 1.97–5.92), while lifetime prevalence of suicide attempt was especially high in gay and bisexual men (RR 4.28, CI 2.32, 7.88). LGB people are at higher risk of mental disorder, suicidal ideation, substance misuse, and deliberate self harm than heterosexual people.

1,836 citations

Journal ArticleDOI
TL;DR: A comprehensive analysis of the 160 dominant CD8+ T-cell responses in 578 untreated HIV-infected individuals from KwaZulu-Natal, South Africa suggested the existence of both effective immune responses and responses lacking demonstrable biological impact in chronic HIV infection.
Abstract: Selection of T-cell vaccine antigens for chronic persistent viral infections has been largely empirical. To define the relationship, at the population level, between the specificity of the cellular immune response and viral control for a relevant human pathogen, we performed a comprehensive analysis of the 160 dominant CD8(+) T-cell responses in 578 untreated HIV-infected individuals from KwaZulu-Natal, South Africa. Of the HIV proteins targeted, only Gag-specific responses were associated with lowering viremia. Env-specific and Accessory/Regulatory protein-specific responses were associated with higher viremia. Increasing breadth of Gag-specific responses was associated with decreasing viremia and increasing Env breadth with increasing viremia. Association of the specific CD8(+) T-cell response with low viremia was independent of HLA type and unrelated to epitope sequence conservation. These population-based data, suggesting the existence of both effective immune responses and responses lacking demonstrable biological impact in chronic HIV infection, are of relevance to HIV vaccine design and evaluation.

1,039 citations

Journal ArticleDOI
TL;DR: In this article, the authors present 39 candidate gravitational wave events from compact binary coalescences detected by Advanced LIGO and Advanced Virgo in the first half of the third observing run (O3a) between 1 April 2019 15:00 UTC and 1 October 2019 15.00.
Abstract: We report on gravitational wave discoveries from compact binary coalescences detected by Advanced LIGO and Advanced Virgo in the first half of the third observing run (O3a) between 1 April 2019 15:00 UTC and 1 October 2019 15:00. By imposing a false-alarm-rate threshold of two per year in each of the four search pipelines that constitute our search, we present 39 candidate gravitational wave events. At this threshold, we expect a contamination fraction of less than 10%. Of these, 26 candidate events were reported previously in near real-time through GCN Notices and Circulars; 13 are reported here for the first time. The catalog contains events whose sources are black hole binary mergers up to a redshift of ~0.8, as well as events whose components could not be unambiguously identified as black holes or neutron stars. For the latter group, we are unable to determine the nature based on estimates of the component masses and spins from gravitational wave data alone. The range of candidate events which are unambiguously identified as binary black holes (both objects $\geq 3~M_\odot$) is increased compared to GWTC-1, with total masses from $\sim 14~M_\odot$ for GW190924_021846 to $\sim 150~M_\odot$ for GW190521. For the first time, this catalog includes binary systems with significantly asymmetric mass ratios, which had not been observed in data taken before April 2019. We also find that 11 of the 39 events detected since April 2019 have positive effective inspiral spins under our default prior (at 90% credibility), while none exhibit negative effective inspiral spin. Given the increased sensitivity of Advanced LIGO and Advanced Virgo, the detection of 39 candidate events in ~26 weeks of data (~1.5 per week) is consistent with GWTC-1.

768 citations