182 research outputs found
Extreme mass-ratio inspirals into black holes surrounded by scalar clouds
We study extreme mass-ratio binary systems in which a stellar mass compact
object spirals into a supermassive black hole surrounded by a scalar cloud.
Scalar clouds can form through superradiant instabilities of massive scalar
fields around spinning black holes and can also serve as a proxy for dark
matter halos. Our framework is fully relativistic and assumes that the impact
of the cloud on the geometry can be treated perturbatively. As a proof of
concept, here we consider a point particle in circular, equatorial motion
around a non-spinning black hole surrounded either by a spherically symmetric
or a dipolar non-axisymmetric scalar cloud, but the framework can in principle
be generalized to generic black hole spins and scalar cloud geometries. We
compute the leading-order power lost by the point particle due to scalar
radiation and show that, in some regimes, it can dominate over
gravitational-wave emission. We confirm the presence of striking signatures due
to the presence of a scalar cloud that had been predicted using Newtonian
approximations, such as resonances that can give rise to sinking and floating
orbits, as well as "sharp features" in the power lost by the particle at given
orbital radii. Finally, for a spherically symmetric scalar cloud, we also
compute the leading-order corrections to the black-hole geometry and to the
gravitational-wave energy flux, focusing only on axial metric perturbations for
the latter. We find that, for non-compact clouds, the corrections to the
(axial) gravitational-wave fluxes at high frequencies can be understood in
terms of a gravitational-redshift effect, in agreement with previous works.Comment: 42 pages, 11 figures; v2: corrected minor typos and a factor 2 error
in the definition of the metric and scalar perturbations that propagated to
the scalar flux calculations. Plots in Sec. III.C and App. G were corrected
accordingl
Diversity of navel microbiome in young adults
Introduction. Human skin microbial communities represent a tremendous source of genetic diversity that evolves as a function of human age. Microbiota differs between regions of oily and moist skin, and appears to stabilize with age.
Aim. We have a minimal understanding of the time frame required for the stabilization of skin microbiota, and the role played by gender. In the current study, we examined the microbiota present in the navel region of college-attending young adults in the age group of 18–25 years and investigated if diversity is associated with gender (male and female).
Method. The study involved 16 female and six male subjects. Isolated DNA samples from navel swabs were processed using the Nextera XT library preparation kit and sequenced using the MiSeq platform. Data were analysed using QIIME and statistical analysis performed in R.
Results. Microbiota of navel skin is dominated by Corynebacterium and Staphylococcus and includes opportunistic pathogens like Clostridium and Pseudomonas . Also present as the major component of the flora were the organisms normally associated with the gastrointestinal tract such as Acinetobacter , Campylobacter , Klebsiella and organisms from the Enterobacteriaceae and Moraxellaceae families. Comparison of alpha and beta diversity of the microbiota in the male and female navel regions suggests that the flora is not statistically different (P\u3e0.05). However, pairwise comparison suggests that the abundance of 12 specific genera varied with gender, including higher abundance of Klebsiella and Enterobacter in females.
Conclusion. Our findings indicate that the navel skin microbiota of young adults has a core microbiota of Corynebacterium and Staphylococcus . We also noted the presence of a significant number of opportunistic pathogens. A minor gender difference in the abundance of individual organisms was also observed
A Sacred and Secular Landscape: Empowering Social Agency
I contend that landscape can provoke an idea for a productive, public space using the people of the city as social agents to create a sensitive rather than oppressive water remediation system. By inventing a program that uses landscape as a water remediation space as well as landscape as a religious and social space, the project will exhibit the idea that social agents can inform a change in the water pollution crisis
Dangerous Abusive Relationships and Sources of Resilience for South Asian Immigrant Women Survivors of Intimate Partner Violence
This study explored South Asian immigrant women survivors’ perspectives on intimate partner relationships that could lead to severe violence or a homicide and sources of resilience for South Asian immigrant survivors in the United States. The study recruited 16 South Asian immigrant survivors for in-depth interviews and focus groups. Data were analyzed using thematic analysis. Survivors shared some characteristics of dangerous partner such as controlling behavior, anger issues, infidelity, alcohol and drug problems, and history of childhood abuse. Incidents of severe physical abuse, threats to kill, possession of a weapon, and suspicious behavior led survivors to feel fearful for their lives. Sources of resilience in the community (e.g., support from formal sources of help) and at the individual level (e.g., education) were discussed. The needs for culturally informed services and to generate awareness of services among South Asian immigrants were highlighted
Linking Microbial Community Structure and Ecosystem Functions in Acidic Soil from Pennsylvania, USA
Microorganisms play a critical role in the structure and functioning of soil ecosystems. Within acidic soil across the northeastern United States and Canada, we have little understanding of the microbial diversity present and its relationship to the biochemical cycles. The current study is aimed at understanding the taxonomical and functional diversities in the acidic soil obtained from near various types of trees, how the diversities change as a function of depth, and the linkage between taxonomical and functional diversities. From eight sampling locations, soil samples were collected from three horizons (depths). The three depths were 0-10 cm (A), 11-25 cm (B), and 26-40 cm (C). Results indicate that across all the samples analyzed, Bradyrhizobium and Candidatus Solibacter are the most abundant bacteria in the soil microbiome. The differences in the soil microbiome across the samples were attributed to the abundance of individual organism’s present in the soil and not to the presence or absence of individual organisms. Subsystem level analysis of the soil microbiome sequences indicate that there is higher level of abundance of genes attributed to regulation and cell signaling. A low level of sequences were detected for sulfur metabolism, potassium metabolism, iron acquisition and metabolism, and phosphorous metabolism. Structure-functional analysis indicate that Bradyrhizobium, Rhodopseudomonas, and Burkholderia are the major organisms involved in the nutritional ecosystem functioning within acidic soil. Based on the results, we propose utilizing a consortium of these organisms as an environmentally friendly alternative to the use of chemicals to maintain soil fertility and ecosystem functioning
Improved Device for Passive Foot Dorsiflexion for Prevention of DVT
Postoperative patients are often too fatigued to walk around and often lay in bed for extended periods of time. This could lead to the development of deep vein thrombosis (DVT). DVT is a condition where blood accumulates in the veins instead of being pushed back to the heart. This can cause the formation of blood clots that can eventually lead to pulmonary embolism resulting in death. DVT is a condition that affects about 900,000 people in the United States. Since it is such a prevalent condition, it is important to develop methods of prevention for this condition.
The aim of this project is to construct a device that will prevent DVT using dorsiflexion of the foot. Currently, the major solution for this problem in postoperative patients is having the patient move around sooner. However, some patients are unable to do this, so this device will be especially influential for these patients. A current medical solution for this problem is the use of anticoagulants which prevent the formation of blood clots by thinning the blood and allowing for better flow. However, this solution is not always feasible with every patient. Another solution for DVT is the use of massagers that are activated when the muscle does not contract enough. The aim of the massager is to physically get the blood moving back towards the heart.
The aim of this project was to create a device that dorsiflexes the foot thereby creating the muscle contraction required. The functional prototype includes a motor and a pulley system that help in raising a platform to create the dorsiflexion. The device implements the use of a microcontroller and a circuit in order to have automatic movement. The total cost for the prototype was around 300 or less. This device can be really beneficial in hospitals and also has applications outside of the hospital in residential settings. There is definitely great commercial potential for this product because it is a better alternative to the current solutions.https://scholarscompass.vcu.edu/capstone/1073/thumbnail.jp
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