Refugee Women\u27s Needs: The Athens Case

Medicins sans Frontiers estimates that twenty-five per cent of new asylum-seeking arrivals in Athens in 2016 were women [1]. Despite the sizable number of women asylum seekers arriving in Athens, women’s voices are often excluded from research on refugee needs. This research sought to understand the needs of women asylum seekers in Athens through the collection of qualitative data on their needs and experiences upon arriving in Athens. Twelve women from Syria, Afghanistan and other countries (background withheld for confidentiality) participated. The sampled women demonstrated an acute understanding of their own needs and the needs of their communities. While many of the women expressed that their own greatest needs at the time of the interviews related to self-sufficiency, they also reflected on their past experiences and daily observations to inform their understandings of the needs of their communities. Although perceived community needs varied based on whether women perceived their communities as permanent or transitory in Athens, unmet basic needs, especially housing, were a theme across women’s responses. The study’s findings also indicate that it would be beneficial for refugee support ecosystems in Greece to shift from a needs-based approach to refugee support to a rights-based approach and that further research into the needs of women refugees in Athens may help shed light on durable solutions for this population

Constraints on Relic Magnetic Black Holes

We present current direct and astrophysical limits on the cosmological abundance of black holes with extremal magnetic charge. Because they don't Hawking radiate, much lighter primordial black holes could exist today if they are extremal. The dominant constraints come from white dwarf destruction for intermediate masses, and intergalactic gas heating for heavier black holes. Extremal magnetic black holes may catalyze proton decay, and thus we derive robust limits -- independent of the catalysis cross section -- from the above as well as from white dwarf heating. We discuss other bounds such as those from neutron star heating, solar neutrino production, binary formation and annihilation into gamma rays, and magnetic field destruction. We note that stable magnetically charged black holes can assist in the formation of neutron star mass black holes.Comment: 49 pages, 6 figures Typos fixed, references added, minor correction in binary merger rate presented in Appendix B which results in slightly stronger constraints on the EMBH abundance from binary merger

Astrophysical Signatures of Dark Matter

My work focuses on using astrophysical and cosmological phenomena to better understand physics beyond the Standard Model. In this work, I explore how heavy decaying relic particles could source the anomalous high energy neutrinos observed by IceCube. I consider two different relic models whose decays produce energetic neutrinos, and consider their impact on the CMB, BBN, and the gamma-ray sky. I find two mass ranges where such relics could produce the anomalous high energy neutrino signal, though not the lower energy signal, without being excluded by cosmological probes. My dark matter research explores whether extremal magnetic black holes (EMBHs) or magnetic black holes (MBHs) could be a viable dark matter candidate. I detail how EMBHs interact with nucleons, ionized gases, compact objects, and themselves. These interactions rule out EMBHs and MBHs as a significant fraction of the dark matter at all masses. I present novel calculations of how magnetic charges interact with Fermi gases at finite temperature and how EMBHs form binaries and merge. I also consider how binary neutron star mergers (BNM) can produce large fluxes of dark photons which ultimately produce an observable gamma-ray flash. Dark photons with masses in the 1-100 MeV range and kinetic mixings in the $10^{-12}-10^{-9}$ range escape the merger remnant, and decay into electrons and positrons which produce a gamma-ray flash. This flash is spectrally, temporally, and spatially distinct from the gamma-ray bursts usually predicted for BNMs, making it a useful probe of the remaining unconstrained parameter space where dark photons can mediate dark matter freeze-in. My most recent work describes binary mergers between dark matter particles or compact structures heavier than $8\times 10^{11}$ GeV. I show how these objects model-independently form gravitationally bound binaries in the early Universe. These binaries lose energy through gravitational radiation, and eventually merge, with many mergers happening in the present. These can produce large electromagnetic or gravitational wave signals depending on the specific dark matter model. This phenomenon is a useful new probe of a wide range of difficult to observe dark matter models

The Effect of Multiple Cooling Channels on the Formation of Dark Compact Objects

A dissipative dark sector can result in the formation of compact objects with masses comparable to stars and planets. In this work, we investigate the formation of such compact objects from a subdominant inelastic dark matter model, and study the resulting distributions of these objects. In particular, we consider cooling from dark Bremsstrahlung and a rapid decay process that occurs after inelastic upscattering. Inelastic transitions introduce an additional radiative processes which can impact the formation of compact objects via multiple cooling channels. We find that having multiple cooling processes changes the mass and abundance of compact objects formed, as compared to a scenario with only one cooling channel. The resulting distribution of these astrophysical compact objects and their properties can be used to further constrain and differentiate between dark sectors.Comment: 20 pages, 4 figure

Axion-sourced fireballs from supernovae

New feebly interacting particles would emerge from a supernova core with 100-MeV-range energies and produce $\gamma$-rays by subsequent decays. These would contribute to the diffuse cosmic $\gamma$-ray background or would have shown up in the Solar Maximum Mission (SMM) satellite from SN~1987A. However, we show for the example of axion-like particles (ALPs) that, even at distances beyond the progenitor star, the decay photons may not escape, and can instead form a fireball, a plasma shell with $T\lesssim 1$ MeV. Thus, existing arguments do not exclude ALPs with few 10 MeV masses and a two-photon coupling of a few $10^{-10}~{\rm GeV}^{-1}$. However, the energy would have showed up in sub-MeV photons, which were not seen from SN 1987A in the Pioneer Venus Orbiter (PVO), closing again this new window. A careful re-assessment is required for other particles that were constrained in similar ways.Comment: 11 pages, 6 figure

Promising Practices and Unfinished Business: Fostering Equity and Excellence for Black and Latino Males

Boston Public Schools (BPS) commissioned companion studies as part of its efforts to address achievement gaps for Black and Latino males. The first study revealed the increasing diversity of Black and Latino males and stark opportunity gaps throughout the system that contribute in large part to wide attainment gaps for these students. We hypothesized that in schools doing comparatively better with Black or Latino males than their counterparts, educators would be strategically and comprehensively implementing evidence-based cultural, structural, and instructional practices tailored to meet their the needs and aspirations of these students. Through qualitative case studies of four schools, we identified several cross-cutting themes that provide the district and school leaders with some positive news about effective practices found in all good schools: strong school cultures, professional collaboration, differentiated instruction, and, in the elementary schools, family engagement. While we observed pockets of best practices specific to Black and Latino male education, we also brought to light unfinished business, in that none of the four case study schools had an intentional and comprehensive schoolwide approach to educating Black and Latino males. This lack of intentionality resulted in a paucity of evidence that the school administration and faculty as a whole: (a) know and value students' cultural and linguistic backgrounds; (b) adopt explicit and responsive approaches to race and gender; and (c) develop and implement a comprehensive approach to culturally responsive curriculum and instruction. We posit that lack of knowledge, intentionality, and coherence impedes further progress in educating Black and Latino males, and has implications for educators in schools, for staff members in community partner organizations, and for family members of BPS students

Epitope mapping of Japanese encephalitis virus neutralizing antibodies by native mass spectrometry and hydrogen/deuterium exchange

Japanese encephalitis virus (JEV) remains a global public health concern due to its epidemiological distribution and the existence of multiple strains. Neutralizing antibodies against this infection have shown efficacy in in vivo studies. Thus, elucidation of the epitopes of neutralizing antibodies can aid in the design and development of effective vaccines against different strains of JEV. Here, we describe a combination of native mass spectrometry (native-MS) and hydrogen/deuterium exchange mass spectrometry (HDX-MS) to complete screening of eight mouse monoclonal antibodies (MAbs) against JEV E-DIII to identify epitope regions. Native-MS was used as a first pass to identify the antibodies that formed a complex with the target antigen, and it revealed that seven of the eight monoclonal antibodies underwent binding. Native mass spectra of a MAb (JEV-27) known to be non-binding showed broad native-MS peaks and poor signal, suggesting the protein is a mixture or that there are impurities in the sample. We followed native-MS with HDX-MS to locate the binding sites for several of the complex-forming antibodies. This combination of two mass spectrometry-based approaches should be generally applicable and particularly suitable for screening of antigen-antibody and other protein-protein interactions when other traditional approaches give unclear results or are difficult, unavailable, or need to be validated

Structural basis of differential neutralization of DENV-1 genotypes by an antibody that recognizes a cryptic epitope

We previously developed a panel of neutralizing monoclonal antibodies against Dengue virus (DENV)-1, of which few exhibited inhibitory activity against all DENV-1 genotypes. This finding is consistent with reports observing variable neutralization of different DENV strains and genotypes using serum from individuals that experienced natural infection or immunization. Herein, we describe the crystal structures of DENV1-E111 bound to a novel CC' loop epitope on domain III (DIII) of the E protein from two different DENV-1 genotypes. Docking of our structure onto the available cryo-electron microscopy models of DENV virions revealed that the DENV1-E111 epitope was inaccessible, suggesting that this antibody recognizes an uncharacterized virus conformation. While the affinity of binding between DENV1-E111 and DIII varied by genotype, we observed limited correlation with inhibitory activity. Instead, our results support the conclusion that potent neutralization depends on genotype-dependent exposure of the CC' loop epitope. These findings establish new structural complexity of the DENV virion, which may be relevant for the choice of DENV strain for induction or analysis of neutralizing antibodies in the context of vaccine development

The Fc region of an antibody impacts the neutralization of West Nile viruses in different maturation states

Flavivirus-infected cells secrete a structurally heterogeneous population of viruses because of an inefficient virion maturation process. Flaviviruses assemble as noninfectious, immature virions composed of trimers of envelope (E) and precursor membrane (prM) protein heterodimers. Cleavage of prM is a required process during virion maturation, although this often remains incomplete for infectious virus particles. Previous work demonstrated that the efficiency of virion maturation could impact antibody neutralization through changes in the accessibility of otherwise cryptic epitopes on the virion. In this study, we show that the neutralization potency of monoclonal antibody (MAb) E33 is sensitive to the maturation state of West Nile virus (WNV), despite its recognition of an accessible epitope, the domain III lateral ridge (DIII-LR). Comprehensive epitope mapping studies with 166 E protein DIII-LR variants revealed that the functional footprint of MAb E33 on the E protein differs subtly from that of the well-characterized DIII-LR MAb E16. Remarkably, aromatic substitutions at E protein residue 306 ablated the maturation state sensitivity of E33 IgG, and the neutralization efficacy of E33 Fab fragments was not affected by changes in the virion maturation state. We propose that E33 IgG binding on mature virions orients the Fc region in a manner that impacts subsequent antibody binding to nearby sites. This Fc-mediated steric constraint is a novel mechanism by which the maturation state of a virion modulates the efficacy of the humoral immune response to flavivirus infection