Estimation of the number of single-photon emitters for multiple fluorophores with the same spectral signature.

Fluorescence microscopy is of vital importance for understanding biological function. However most fluorescence experiments are only qualitative inasmuch as the absolute number of fluorescent particles can often not be determined. Additionally, conventional approaches to measuring fluorescence intensity cannot distinguish between two or more fluorophores that are excited and emit in the same spectral window, as only the total intensity in a spectral window can be obtained. Here we show that, by using photon number resolving experiments, we are able to determine the number of emitters and their probability of emission for a number of different species, all with the same measured spectral signature. We illustrate our ideas by showing the determination of the number of emitters per species and the probability of photon collection from that species, for one, two, and three otherwise unresolvable fluorophores. The convolution Binomial model is presented to model the counted photons emitted by multiple species. And then the Expectation-Maximization (EM) algorithm is used to match the measured photon counts to the expected convolution Binomial distribution function. In applying the EM algorithm, to leverage the problem of being trapped in a sub-optimal solution, the moment method is introduced in finding the initial guess of the EM algorithm. Additionally, the associated Cram\'er-Rao lower bound is derived and compared with the simulation results.

Estimation of the number of single-photon emitters for multiple fluorophores with the same spectral signature.

Fluorescence microscopy is of vital importance for understanding biological function. However, most fluorescence experiments are only qualitative inasmuch as the absolute number of fluorescent particles can often not be determined. Additionally, conventional approaches to measuring fluorescence intensity cannot distinguish between two or more fluorophores that are excited and emit in the same spectral window, as only the total intensity in a spectral window can be obtained. Here we show that, by using photon number resolving experiments, we are able to determine the number of emitters and their probability of emission for a number of different species, all with the same measured spectral signature. We illustrate our ideas by showing the determination of the number of emitters per species and the probability of photon collection from that species, for one, two and three otherwise unresolvable fluorophores. The convolution binomial model is presented to represent the counted photons emitted by multiple species. Then, the expectation-maximization (EM) algorithm is used to match the measured photon counts to the expected convolution binomial distribution function. In applying the EM algorithm, to leverage the problem of being trapped in a sub-optimal solution, the moment method is introduced to yield an initial guess for the EM algorithm. Additionally, the associated Cramér-Rao lower bound is derived and compared with the simulation results.

Street Culture and Gun Violence: Exploring the Reputation-Victimization Paradox.

Anderson's thesis of a code of the street has been broadly applied to the study of violence, but race- and gender-specific multilevel analyses of gun violence are scant within the literature. An unresolved debate also surrounds the link between violent victimization and adherence to street culture; underscored by an apparent reputation-victimization paradox among those who engage in street behaviors. The current study contributes to the literature by assessing the direct influence of incident setting and victim-offender familiarity on the likelihood of gun use by Black males in the course of aggravated assaults; and the degree to which the confluence of these factors is conditioned by levels of disadvantage and violence in the community. To accomplish this, we apply hierarchical generalized linear modeling to incident-level data from the National Incident-Based Reporting System in conjunction with contextual-level data from the counties in which the incidents are nested. Our findings suggest victim-offender familiarity and public settings are negatively associated with gun violence and the confluence of these factors further reduces the probability of gun use. This relationship, however, is conditioned by levels of disadvantage and violence in the community, providing preliminary evidence of both the violence increasing and decreasing effects of street culture hypothesized by Anderson.

How COVID-19's Disruption of the U.S. Correctional System Provides an Opportunity for Decarceration.

The COVID-19 pandemic has amplified decades of vulnerabilities, disparities, and injustices within the U.S. correctional system. The spread of the coronavirus poses a particularly serious threat to those that comprise the system, including personnel, attorneys, prisoners, their families and extends into the communities in which facilities are located. These correctional facilities and communities were especially underprepared for the sudden onset of a highly contagious virus, which has resulted in an exceedingly high number of infections among those who work and are held in the facilities. Rampant overcrowding in the U.S. correctional system, an aging population, and a population exhibiting high rates of underlying health conditions are highly likely to exacerbate the spread of this highly contagious virus. This potentially dire set of interrelated circumstances necessitates rapid decarceration measures that effectively balance public safety and public health. Unfortunately, there has been unclear guidance as well as changing and even contradictory information coming from the federal government concerning rapid measures to mitigate the spread of infection to justice system personnel and federal prisoners. In this paper we summarize the federal response and how it has impacted those responsible for implementation. Furthermore, we discuss how systemic deleterious conditions of the U.S. correctional system serve as both accelerants to as well as effects of the pandemic. We end highlighting critical issues relating to early release due to COVID-19 that will necessitate future research.

Gender Differences in Health Care Needs and Service Attainment Among Violent Offenders.

Research has determined that female inmates experience distinctive challenges both during and after incarceration. There has been little empirical inquiry, however, into the gendered nature of medical health care needs and treatment postrelease. The purpose of this study, therefore, is to examine the differences between male and female inmates with regard to chronic illness diagnoses and health care receipt during reentry. This was done using a subsample of 763 inmates who participated in the Serious and Violent Offender Reentry Initiative multisite impact evaluation who specifically mentioned a need for medical health care treatment. Results of multivariate analyses showed gendered differences for both chronic illness diagnoses and medical treatment receipt postrelease, thus highlighting potential implications for correctional health care policy and resource distribution.