A Participatory Model for Evaluating Social Programs

Describes the participatory approach to evaluation, which emphasizes client participation in the design and implementation process

Alligator Skull

Artist Statement Alligator Skull was created through mimicking the shadows on the bones of a giant creature with the dots of my pen. Living in Florida, I have known these animals my entire life, and I have been mesmerized by them the whole time. To see one humbled into a skeleton form is so intriguing. They are apex predators that encompass fear in many, but they are just as mortal as the rest of us. They only kill to survive, but the power they possess over the waters has humans either petrified or entranced. This individual from the Alligator mississippiensis species was only in its youth before death overcame its being. It was stripped from the muscle that could kill by something so gentle as degradation. I have always been an artist who has sought after realism. I want to encapsulate the exact beauty that I see on paper. I fought through this piece because the further you are from it, the more real it appears to be—as the dots blur together, yet a closer look reveals chaos. This is inevitable as it was created through the shadowing technique of stippling—an intriguing style made by strategically tapping a pen to paper at least hundreds of times. One tap seems to have done nothing, but a couple hundred brings back life to a skull. I am majoring in biology, with a concentration in coastal environmental science, and minoring in painting, drawing, and printmaking at the University of North Florida. Studying these subjects for years has brought me to a point where I adore scientific illustration. Combining the meditation and skill of art with the knowledge and curiosity of science makes creating these pieces a fascinating experience. When fabricating this piece, I did not stop at finding an aesthetic image, as my usual approach would suggest; instead, I researched the functions of the different bones and the reasons for the specks on the bones. I truly love illustrating in this way. This piece was only a start

Improved mathematical and computational tools for modeling photon propagation in tissue

Thesis (Ph.D.)--Boston UniversityLight interacts with biological tissue through two predominant mechanisms: scattering and absorption, which are sensitive to the size and density of cellular organelles, and to biochemical composition (ex. hemoglobin), respectively. During the progression of disease, tissues undergo a predictable set of changes in cell morphology and vascularization, which directly affect their scattering and absorption properties. Hence, quantification of these optical property differences can be used to identify the physiological biomarkers of disease with interest often focused on cancer. Diffuse reflectance spectroscopy is a diagnostic tool, wherein broadband visible light is transmitted through a fiber optic probe into a turbid medium, and after propagating through the sample, a fraction of the light is collected at the surface as reflectance. The measured reflectance spectrum can be analyzed with appropriate mathematical models to extract the optical properties of the tissue, and from these, a set of physiological properties. A number of models have been developed for this purpose using a variety of approaches -- from diffusion theory, to computational simulations, and empirical observations. However, these models are generally limited to narrow ranges of tissue and probe geometries. In this thesis, reflectance models were developed for a much wider range of measurement parameters, and influences such as the scattering phase function and probe design were investigated rigorously for the first time. The results provide a comprehensive understanding of the factors that influence reflectance, with novel insights that, in some cases, challenge current assumptions in the field. An improved Monte Carlo simulation program, designed to run on a graphics processing unit (GPU), was built to simulate the data used in the development of the reflectance models. Rigorous error analysis was performed to identify how inaccuracies in modeling assumptions can be expected to affect the accuracy of extracted optical property values from experimentallyacquired reflectance spectra. From this analysis, probe geometries that offer the best robustness against error in estimation of physiological properties from tissue, are presented. Finally, several in vivo studies demonstrating the use of reflectance spectroscopy for both research and clinical applications are presented

Low-intensity land use in grassland catchments: Effects on a large, oligotrophic lake

In southern New Zealand, many upland streams drain into large oligotrophic lakes surrounded by native grassland, low-intensity farming, and small urban centers. Little work has been undertaken to determine the impact low-intensity development has on nutrient dynamics and microbial activity in these large lake systems. Lake Wanaka, Central Otago, was chosen as a study site since the recent appearance of nuisance organic aggregates and changes in phytoplankton community structure suggest the lake is not in a steady state. Research undertaken for this project included intensive sampling of tributaries to the lake during different seasons and hydrological conditions, following the path of two tributaries out into the lake, and laboratory-based experiments. In the Wanaka catchment, pasture cover correlated positively with stream dissolved organic carbon (DOC), total nitrogen (TN) and nitrate-nitrogen (NO3-N) concentrations. Nitrogen concentrations were not influenced by weather-related variables, but temperature and soil moisture mitigated the influence of pasture cover on surface water DOC concentration under very dry or wet conditions. Neither land use nor weather-related conditions correlated with total phosphorus (TP) or dissolved phosphorus (DRP) concentrations in streams, possibly reflecting good P-binding in soils, low-intensity agriculture in the catchment and/or lack of sampling during high flow events. Amending lake water with stream water in the laboratory did not influence the production of sticky polysaccharides (i.e. transparent exopolymer particles (TEP)), but enriching treatments with high concentrations of N and P increased TEP 1.7 to 9.3 times over unamended treatments. Phytoplankton cell numbers, diatom abundance, and chl a also increased in response to nutrient-enrichment, and organic aggregates were visible in nutrient-enriched treatments within 6 days. In the field, the intermixing depth of a main river inflow varied under stratified and un-stratified conditions, affecting where catchment-derived material was delivered in the Lake. Nutrient and DOC concentrations in the Matukituki River were within range of the Lake, and the river plume was capable of stimulating phytoplankton growth in nearshore waters. Despite similar bulk DOC concentrations, dissolved organic matter (DOM) character and lability differed between the River and the Lake. DOM from deep-sourced lake water contained more aromatic, refractory structures than shallower lake water or river water. The river had almost double the number of organic sulphur compounds than the lake, including potential sulfonates. The source of the S is unknown, but may be geologic in origin or reflect agricultural activity in the River catchment. In the laboratory, riverine bacterial communities could break down a diverse array of organic substances regardless of season, suggesting a consistent labile supply of DOM. In contrast, organic substrate use patterns in the lake were seasonal, and varied by depth. Lake water amended with Matukituki River water stimulated bacterial respiration and uptake of DOC and P, but did not affect bacterial productivity, which may reflect limitations of the experimental design. My results indicate low intensity land use in grassland catchments affects nutrient flux and microbial processes in Lake Wanaka. These data provide a foundation for future research on land development and microbial dynamics in similar large, oligotrophic lake systems

UNCOVER: Illuminating the Early Universe—JWST/NIRSpec Confirmation of z \u3e 12 Galaxies

Observations of high-redshift galaxies provide a critical direct test to the theories of early galaxy formation, yet to date, only three have been spectroscopically confirmed at z \u3e 12. Due to strong gravitational lensing over a wide area, the galaxy cluster field A2744 is ideal for searching for the earliest galaxies. Here we present JWST/NIRSpec observations of two galaxies: a robust detection at zspec 12.393 0.001 0.004 = - + , and a plausible candidate at zspec 13.079 0.001 0.013 = - + . The galaxies are discovered in JWST/NIRCam imaging and their distances are inferred with JWST/NIRSpec spectroscopy, all from the JWST Cycle 1 UNCOVER Treasury survey. Detailed stellar population modeling using JWST NIRCam and NIRSpec data corroborates the primeval characteristics of these galaxies: low mass (∼108 Me), young, rapidly assembling, metal-poor, and star-forming. Interestingly, both galaxies are spatially resolved, having lensing-corrected rest-UV effective radii on the order of 300–400 pc, which are notably larger than other spectroscopically confirmed systems at similar redshifts. The observed dynamic range of z 10 sizes spans over 1 order of magnitude, implying a significant scatter in the size–mass relation at early times. Deep into the epoch of reionization, these discoveries elucidate the emergence of the first galaxies

UNCOVER: The Growth of the First Massive Black Holes from JWST/NIRSpec—Spectroscopic Redshift Confirmation of an X-Ray Luminous AGN at z = 10.1

The James Webb Space Telescope is now detecting early black holes (BHs) as they transition from seeds to supermassive BHs. Recently, Bogdan et al. reported the detection of an X-ray luminous supermassive BH, UHZ-1, with a photometric redshift at z \u3e 10. Such an extreme source at this very high redshift provides new insights on seeding and growth models for BHs given the short time available for formation and growth. Harnessing the exquisite sensitivity of JWST/NIRSpec, here we report the spectroscopic confirmation of UHZ-1 at z = 10.073 ± 0.002. We find that the NIRSpec/Prism spectrum is typical of recently discovered z ≈ 10 galaxies, characterized primarily by star formation features. We see no clear evidence of the powerful X-ray source in the rest-frame UV/optical spectrum, which may suggest heavy obscuration of the central BH, in line with the Compton-thick column density measured in the X-rays. We perform a stellar population fit simultaneously to the new NIRSpec spectroscopy and previously available photometry. The fit yields a stellar-mass estimate for the host galaxy that is significantly better constrained than prior photometric estimates (�⋆∼1.4−0.4+0.3×108M⊙). Given the predicted BH mass (MBH ∼ 107–108M⊙), the resulting ratio of MBH/M⋆ remains 2 to 3 orders of magnitude higher than local values, thus lending support to the heavy seeding channel for the formation of supermassive BHs within the first billion years of cosmic evolution

UNCOVER Spectroscopy Confirms the Surprising Ubiquity of Active Galactic Nuclei in Red Sources at z \u3e 5

The James Webb Space Telescope is revealing a new population of dust-reddened broad-line active galactic nuclei (AGN) at redshifts z ≳ 5. Here we present deep NIRSpec/Prism spectroscopy from the Cycle 1 Treasury program Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization (UNCOVER) of 15 AGN candidates selected to be compact, with red continua in the rest-frame optical but with blue slopes in the UV. From NIRCam photometry alone, they could have been dominated by dusty star formation or an AGN. Here we show that the majority of the compact red sources in UNCOVER are dust-reddened AGN: 60% show definitive evidence for broad-line Hα with a FWHM \u3e 2000 km s −1, 20% of the current data are inconclusive, and 20% are brown dwarf stars. We propose an updated photometric criterion to select red z \u3e 5 AGN that excludes brown dwarfs and is expected to yield \u3e80% AGN. Remarkably, among all zphot \u3e 5 galaxies with F277W – F444W \u3e 1 in UNCOVER at least 33% are AGN regardless of compactness, climbing to at least 80% AGN for sources with F277W – F444W \u3e 1.6. The confirmed AGN have black hole masses of 107–109M⊙. While their UV luminosities (−16 \u3e MUV \u3e −20 AB mag) are low compared to UV-selected AGN at these epochs, consistent with percent-level scattered AGN light or low levels of unobscured star formation, the inferred bolometric luminosities are typical of 107–109M⊙ black holes radiating at ∼10%–40% the Eddington limit. The number densities are surprisingly high at ∼10−5 Mpc−3 mag−1, 100 times more common than the faintest UV-selected quasars, while accounting for ∼1% of the UV-selected galaxies. While their UV faintness suggests they may not contribute strongly to reionization, their ubiquity poses challenges to models of black hole growth

COVID-19, colleagues, confusion, and conversations

During the COVID-19 pandemic, doctors in a community hospital reflect on their decision-making regarding treatment options for COVID-19. Whether to use hydroxychloroquine is the treatment discussed in most detail