Constraints on relic magnetic black holes Diamond, Melissa D.; Kaplan, David E.
The journal of high energy physics,
03/2022, Letnik:
2022, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A
bstract
We present current direct and astrophysical limits on the cosmological abundance of black holes with extremal magnetic charge. Such black holes do not Hawking radiate, allowing those ...normally too light to survive to the present to do so. The dominant constraints come from white dwarf destruction for low and intermediate masses (2
×
10
−
5
g – 4
×
10
12
g) and Galactic gas cloud heating for heavier masses (
>
4 × 10
12
g). Extremal magnetic black holes may catalyze proton decay. We derive robust limits — independent of the catalysis cross section — from the effect this has on white dwarfs. We discuss other bounds from neutron star heating, solar neutrino production, binary formation and annihilation into gamma-rays, and magnetic field destruction. Stable magnetically charged black holes can assist in the formation of neutron star mass black holes.
In this Letter we begin the study of visible dark sector signals coming from binary neutron star mergers. We focus on dark photons emitted in the 10 ms-1 s after the merger, and show how they can ...lead to bright transient γ-ray signals. The signal will be approximately isotropic, and for much of the interesting parameter space will be close to thermal, with an apparent temperature of ∼100 keV. These features can distinguish the dark photon signal from the expected short γ-ray bursts produced in neutron star mergers, which are beamed in a small angle and nonthermal. We calculate the expected signal strength and show that for dark photon masses in the 1-100 MeV range it can easily lead to total luminosities larger than 10^{46} ergs for much of the unconstrained parameter space. This signal can be used to probe a large fraction of the unconstrained parameter space motivated by freeze-in dark matter scenarios with interactions mediated by a dark photon in that mass range. We also comment on future improvements when proposed telescopes and midband gravitational detectors become operational.
Binary collisions of dark matter blobs Diamond, Melissa D.; Kaplan, David E.; Rajendran, Surjeet
The journal of high energy physics,
01/2023, Letnik:
2023, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A
bstract
We describe the model-independent mechanism by which dark matter and dark matter structures heavier than ~ 8 × 10
11
GeV form binary pairs in the early Universe that spin down and merge ...both in the present and throughout the Universe’s history, producing potentially observable signals. Sufficiently dense dark objects will dominantly collide through binary mergers instead of random collisions. We detail how one would estimate the merger rate accounting for finite size effects, multibody interactions, and friction with the thermal bath. We predict how mergers of dark dense objects could be detected through gravitational and electromagnetic signals, noting that such mergers could be a unique source of high frequency gravitational waves. We rule out objects whose presence would contradict observations of the CMB and diffuse gamma-rays.
A
bstract
We consider long-lived relic particles as the source of the PeV-scale neutrinos detected at the IceCube observatory over the last six years. We derive the present day neutrino flux, ...including primary neutrinos from direct decays, secondary neutrinos from electroweak showering, and tertiary neutrinos from re-scatters off the relic neutrino background. We compare the high-energy neutrino flux prediction to the most recently available datasets and find qualitative differences to expected spectra from other astrophysical processes. We utilize electroweak corrections to constrain heavy decaying relic abundances, using measurements impacted by electromagnetic energy injection, such as light element abundances during Big Bang nucleosynthesis, cosmic microwave background anisotropies, and diffuse
γ
-ray spectra. We compare these abundances to those necessary to source the IceCube neutrinos and find two viable regions in parameter space, ultimately testable by future neutrino,
γ
-ray, and cosmic microwave background observatories.
Since 2012, more than three million Syrian refugees have fled to Turkey. While these refugees vary in socioeconomic background, it is notable that 50% of Syrian refugee children in Turkey display ...symptoms of post-traumatic stress and that more than 663,138 of these children between the ages of six and seventeen are not enrolled in school. For those children who are in school, high levels of trauma have significant implications for the education system as trauma alters the brain and affects the way children learn. A Global Voice for Autism is an international non-governmental relief and development organization that exists to equip teachers and families in conflict-affected communities. Its intent is to support the development and success of children with autism and trauma-related behavioral challenges in their classrooms, home, and communities. The instabilities inherent in the Syrian refugee experience pose a number of challenges to the organization’s effective implementation of programming. The experiences of refugees in Turkey are highly gendered. Therefore, a qualitative gender analysis was conducted to address and better understand the challenges faced when carrying out these educational interventions. The article examines domestic violence, sexual violence, and masculinity as gender-driven constructs that influence how refugees experience trauma. In addition, structural issues in existing support systems all present significant challenges to Syrian refugee parents that impede effective program implementation. It is imperative to assess structural issues in existing support services to address these challenges and to successfully carry out meaningful and impactful programming. This Brief Report provides a series of recommendations in order to ameliorate these challenges and increase the efficacy of educational interventions with Syrian refugee parents of trauma-affected and vulnerable children in Turkey. It concludes with a call for policy changes that protect refugees from deportation when accessing support services and a network of services that do not require residency permits. It calls for increased integration of parent trauma support in educational intervention trainings and the creation of safe spaces where mothers and fathers can discuss their own trauma and challenges in the hope of significantly enhancing program efficacy.
Pericardial effusion (PE) is a known complication after hematopoietic stem cell transplant (HSCT). Limited data is currently available regarding the incidence and outcomes of PE in pediatric HSCT.
We ...conducted a retrospective study on a cohort of patients who underwent HSCT between 2004 and 2015. Risk factors associated with development of PE were evaluated.
In 111 HSCT, stem cell source was bone marrow in 37 (33.3%), peripheral blood-42 (37.8%) and cord blood-32 (28.8%). Incidence of PE after HSCT was 37.8%. Insignificant effusion (trivial or small) was noted in 30 (27.0%) transplants, and significant (moderate or large) PE in 12 (10.8%). There were no associations between incidence of effusion and stem cell source, graft versus host disease or CMV infection. Risk factors associated with development of PE included systemic hypertension (P<0.05), total body irradiation (P<0.05), and sinusoidal obstruction syndrome formerly known as venoocclusive disease (P=0.03). Overall mortality was 22.5% after HSCT, but 38.1% among those with effusion (P<0.05). None of these deaths were attributed to primary cardiac etiologies.
The incidence of PE in this cohort of pediatric HSCT recipients is high and associated with higher morbidity and mortality.
Pediatric cardiomyopathies, which are rare but serious disorders of the muscles of the heart, affect at least one in every 100,000 children in the USA. Approximately 40% of children with symptomatic ...cardiomyopathy undergo heart transplantation or die from cardiac complications within 2 years. However, a significant number of children suffering from cardiomyopathy are surviving into adulthood, making it an important chronic illness for both pediatric and adult clinicians to understand. The natural history, risk factors, prevalence and incidence of this pediatric condition were not fully understood before the 1990s. Questions regarding optimal diagnostic, prognostic and treatment methods remain. Children require long-term follow-up into adulthood in order to identify the factors associated with best clinical practice including diagnostic approaches, as well as optimal treatment approaches. In this article, we comprehensively review current research on various presentations of this disease, along with current knowledge about their causes, treatments and clinical outcomes.
In the US, children diagnosed with cancer are living longer, but not without consequences from the same drugs that cured their cancer. In these patients, cardiovascular disease is the leading cause ...of non-cancer-related morbidity and mortality. Although this review focuses on anthracycline-related cardiomyopathy in childhood cancer survivors, the global lifetime risk of other cardiovascular diseases such as atherosclerosis, arrhythmias and intracardiac conduction abnormalities, hypertension, and stroke also are increased. Besides anthracyclines, newer molecularly targeted agents, such as vascular endothelial growth factor receptor and tyrosine kinase inhibitors, also have been associated with acute hypertension, cardiomyopathy, and increased risk of ischemic cardiac events and arrhythmias, and are summarized here. This review also covers other risk factors for chemotherapy-related cardiotoxicity (including both modifiable and non-modifiable factors), monitoring strategies (including both blood and imaging-based biomarkers) during and following cancer treatment, and discusses the management of cardiotoxicity (including prevention strategies such as cardioprotection by use of dexrazoxane).
Abstract
Background
Therapeutic targeting of host-cell factors required for SARS-CoV-2 entry is an alternative strategy to ameliorate COVID-19 severity. SARS-CoV-2 entry into lung epithelium requires ...the TMPRSS2 cell surface protease. Pre-clinical and correlative data in humans suggest that anti-androgenic therapies can reduce the expression of TMPRSS2 on lung epithelium. Accordingly, we hypothesize that therapeutic targeting of androgen receptor signaling via degarelix, a luteinizing hormone-releasing hormone (LHRH) antagonist, will suppress COVID-19 infection and ameliorate symptom severity.
Methods
This is a randomized phase 2, placebo-controlled, double-blind clinical trial in 198 patients to compare efficacy of degarelix plus best supportive care versus placebo plus best supportive care on improving the clinical outcomes of male Veterans who have been hospitalized due to COVID-19. Enrolled patients must have documented infection with SARS-CoV-2 based on a positive reverse transcriptase polymerase chain reaction result performed on a nasopharyngeal swab and have a severity of illness of level 3–5 (hospitalized but not requiring invasive mechanical ventilation). Patients stratified by age, history of hypertension, and severity are centrally randomized 2:1 (degarelix: placebo). The composite primary endpoint is mortality, ongoing need for hospitalization, or requirement for mechanical ventilation at 15 after randomization. Important secondary endpoints include time to clinical improvement, inpatient mortality, length of hospitalization, duration of mechanical ventilation, time to achieve a normal temperature, and the maximum severity of COVID-19 illness. Exploratory analyses aim to assess the association of cytokines, viral load, and various comorbidities with outcome. In addition, TMPRSS2 expression in target tissue and development of anti-viral antibodies will also be investigated.
Discussion
In this trial, we repurpose the FDA approved LHRH antagonist degarelix, commonly used for prostate cancer, to suppress TMPRSS2, a host cell surface protease required for SARS-CoV-2 cell entry. The objective is to determine if temporary androgen suppression with a single dose of degarelix improves the clinical outcomes of patients hospitalized due to COVID-19.
Trial registration
ClinicalTrials.gov
NCT04397718. Registered on May 21, 2020
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