2,528 research outputs found
41SM195A, The Browning Site
A surface collection of early 19 \u27 century historic sherds led to archaeological investigations in 2002 and 2003 at the Browning site (41SM195A) in eastern Smith County, Texas. My interest was whetted by mention in the original land abstract that the property had once been deeded to the Cherokee Indians. In all, a total of 6.5 cubic meters of archaeological deposits was excavated at the site, including 22 shovel tests and 10 1 x 1 m test units, and fine-screen and flotation samples were taken from a prehistoric midden deposit identified during the work. As a result, 1075 prehistoric and historic artifacts were recovered, along with new information about Woodland period archaeology in this part of East Texas.
The initial shovel tests found, in addition to the historic component, a buried midden with evidence of Woodland period occupation. Based on the excavations, the midden covered approximately 500 square meters. The 19th century historic artifacts were found in the upper sediment zone, a brown sandy loam that was mostly gravel- free) covering the midden. The buried midden was a dark yellowish-brown gravelly loam that contained prehistoric pottery, animal bone, charred wood and nutshells, lithic materials, including lithic debris, flake tools, arrow and dart points, and ground stone tools. A calibrated radiocarbon date of A.D. 625 to 880, with a calibrated intercept of A.D. 685, was obtained on charred nutshell from 40-50 em bs in the midden zone. A series of Oxidizable Carbon Ratio (OCR) dates from the midden indicate that the midden began to from about A.D. 147, with dates of A.D. 357-815 from the main part of the midden, indicating when the Browning site was most intensively occupied in prehistoric times
CODEX: A Cluster-Based Method for Explainable Reinforcement Learning
Despite the impressive feats demonstrated by Reinforcement Learning (RL),
these algorithms have seen little adoption in high-risk, real-world
applications due to current difficulties in explaining RL agent actions and
building user trust. We present Counterfactual Demonstrations for Explanation
(CODEX), a method that incorporates semantic clustering, which can effectively
summarize RL agent behavior in the state-action space. Experimentation on the
MiniGrid and StarCraft II gaming environments reveals the semantic clusters
retain temporal as well as entity information, which is reflected in the
constructed summary of agent behavior. Furthermore, clustering the
discrete+continuous game-state latent representations identifies the most
crucial episodic events, demonstrating a relationship between the latent and
semantic spaces. This work contributes to the growing body of work that strives
to unlock the power of RL for widespread use by leveraging and extending
techniques from Natural Language Processing.Comment: Presented at the International Joint Conference on Artificial
Intelligence (IJCAI) 2023 Workshop on Explainable Artificial Intelligence
(XAI
Theoretical investigation of finite size effects at DNA melting
We investigated how the finiteness of the length of the sequence affects the
phase transition that takes place at DNA melting temperature. For this purpose,
we modified the Transfer Integral method to adapt it to the calculation of both
extensive (partition function, entropy, specific heat, etc) and non-extensive
(order parameter and correlation length) thermodynamic quantities of finite
sequences with open boundary conditions, and applied the modified procedure to
two different dynamical models. We showed that rounding of the transition
clearly takes place when the length of the sequence is decreased. We also
performed a finite-size scaling analysis of the two models and showed that the
singular part of the free energy can indeed be expressed in terms of an
homogeneous function. However, both the correlation length and the average
separation between paired bases diverge at the melting transition, so that it
is no longer clear to which of these two quantities the length of the system
should be compared. Moreover, Josephson's identity is satisfied for none of the
investigated models, so that the derivation of the characteristic exponents
which appear, for example, in the expression of the specific heat, requires
some care
Comparing the effects of two inhaled glucocorticoids on allergen-induced bronchoconstriction and markers of systemic effects, a randomised cross-over double-blind study
<p>Abstract</p> <p>Background</p> <p>Inhaled glucocorticoids are efficient in protecting against asthma exacerbations, but methods to compare their efficacy vs systemic effects have only been attempted in larger multi-centre studies. The aim of the current study was therefore to directly compare the effects of two separate inhaled glucocorticoids, mometasone and budesonide, to compare the effects on the early and late asthmatic responses to inhaled allergen in patients with mild allergic asthma, and sputum eosinophils, and to relate the clinical positive effects to any systemic effects observed.</p> <p>Methods</p> <p>Twelve patients with documented early and late asthmatic responses (EAR and LAR) to inhaled allergen at a screening visit were randomized in a double-blind fashion to treatment with mometasone (200 ÎŒg Ă 2 or 400 ÎŒg Ă 2), budesonide (400 ÎŒg Ă 2) or placebo in a double-blind crossover fashion for a period of seven days. Challenge with the total allergen dose causing both an EAR and LAR was given on the last day of treatment taken in the morning. Lung function was assessed using FEV1, and systemic glucocorticoid activity was quantified using 24 h urinary cortisol.</p> <p>Results</p> <p>Mometasone and budesonide attenuate both EAR and LAR to allergen to a similar degree. No significant dose-related effects on the lung function parameters were observed. Both treatments reduced the relative amount of sputum eosinophils (%) after allergen. At the dose of 800 ÎŒg daily, mometasone reduced 24 h urinary cortisol by approximately 35%. Both drugs were well tolerated.</p> <p>Conclusions</p> <p>Mometasone and budesonide are equieffective in reducing early and late asthmatic responses induced by inhaled allergen challenge. Mometasone 800 ÎŒg given for seven days partially affects the HPA axis.</p
Influence of dietary protein on glomerular filtration before and after bariatric surgery: a cohort study
BACKGROUND:
Obesity-associated elevations in glomerular filtration rate (GFR) are common and may play a role in the development of kidney disease, so identifying the underlying mechanism is important. We therefore studied whether reductions in dietary protein intake, which is known to modulate GFR, explain why GFR decreases after bariatric surgery-induced weight loss.
STUDY DESIGN:
Cohort study with participants as their own controls.
SETTING & PARTICIPANTS:
8 severely obese patients with normal kidney function were recruited from bariatric surgery centers in Indianapolis, IN. All participants were placed on a fixed-protein (50-g/d) diet for 1 week before and after a minimum of a 20-kg weight loss by bariatric surgery and were followed up closely by dieticians for adherence.
PREDICTOR:
Ad lib versus low-protein diet before versus after bariatric surgery.
OUTCOME:
Measured GFR, using repeated-measures analysis, was used to estimate the independent effects of diet and surgery.
MEASUREMENT:
GFR was measured using plasma iohexol clearance.
RESULTS:
A median of 32.9 (range, 19.5-54.4)kg was lost between the first presurgery visit and first postsurgery visit. Dietetic evaluations and urinary urea excretion confirmed that patients generally adhered to the study diet. GFRs on an ad lib diet were significantly higher before compared to after surgery (GFR medians were 144 (range, 114-178) and 107 (range, 85-147) mL/min, respectively; P=0.01). Although bariatric surgery (-26mL/min; P=0.005) and dietary sodium intake (+7.5mL/min per 100mg of dietary sodium; P=0.001) both influenced GFR, consuming a low-protein diet did not (P=0.7).
LIMITATIONS:
Small sample size; mostly white women; possible lack of generalizability.
CONCLUSIONS:
The decrease in GFR observed after bariatric surgery is explained at least in part by the effects of surgery and/or dietary sodium intake, but not by low dietary protein consumption
NASA Space Flight Vehicle Fault Isolation Challenges
The Space Launch System (SLS) is the new NASA heavy lift launch vehicle and is scheduled for its first mission in 2017. The goal of the first mission, which will be uncrewed, is to demonstrate the integrated system performance of the SLS rocket and spacecraft before a crewed flight in 2021. SLS has many of the same logistics challenges as any other large scale program. Common logistics concerns for SLS include integration of discrete programs geographically separated, multiple prime contractors with distinct and different goals, schedule pressures and funding constraints. However, SLS also faces unique challenges. The new program is a confluence of new hardware and heritage, with heritage hardware constituting seventy-five percent of the program. This unique approach to design makes logistics concerns such as testability of the integrated flight vehicle especially problematic. The cost of fully automated diagnostics can be completely justified for a large fleet, but not so for a single flight vehicle. Fault detection is mandatory to assure the vehicle is capable of a safe launch, but fault isolation is another issue. SLS has considered various methods for fault isolation which can provide a reasonable balance between adequacy, timeliness and cost. This paper will address the analyses and decisions the NASA Logistics engineers are making to mitigate risk while providing a reasonable testability solution for fault isolation
NASA Space Flight Vehicle Fault Isolation Challenges
The Space Launch System (SLS) is the new NASA heavy lift launch vehicle in development and is scheduled for its first mission in 2018.SLS has many of the same logistics challenges as any other large scale program. However, SLS also faces unique challenges related to testability. This presentation will address the SLS challenges for diagnostics and fault isolation, along with the analyses and decisions to mitigate risk.
Studies of high temperature sliding wear of metallic dissimilar interfaces
The evolution of microstructures in the glaze layer formed during limited debris retention sliding wear of Nimonic 80A against Stellite 6 at 750 8C and a sliding speed of 0.314 m sK1 (7 N applied load, 4522 m sliding distance) was investigated using scanning electron microscopy (SEM), energy dispersive analysis by X-ray (EDX), X-ray diffraction (XRD), scanning tunnelling microscopy (STM) and transmission electron microscopy (TEM). The collected data indicate the development of a wear resistant nano-structured glaze layer. The process of âfragmentationâ involving deformation, generation of dislocations, formation of sub-grains and their increasing refinement causing increasing misorientation was responsible for the formation of nano-structured grains. The rapid formation of this glaze layer from primarily cobaltâchromium debris transferred from (and also back to) the surface of the Stellite 6, kept wear of both the Nimonic 80A and Stellite 6 to very low levels. However, increasing the sliding speed to 0.905 m sK1 (750 8C) suppressed glaze formation with only a patchy, unstable glaze forming on the Stellite 6 counterface and an absence of glaze development on the Nimonic 80A sample (the Nimonic 80A surface was covered with at most, a very thinly smeared layer of oxide). The high levels of oxide debris generated at 0.905 m sK1 instead acted as a loose abrasive assisting wear of especially the Nimonic 80A. This behaviour was attributed to a change in oxide chemistry (due to the dominance of nickel and chromium oxides generated from the Nimonic 80A) resulting in poor oxide sintering characteristics, in combination with increased mobility and reduced residency of the oxide debris at 0.905 m sK1
Videos of sipuleucel-T programmed T cells lysing cells that express prostate cancer target antigens
Sipuleucel-T, an autologous cellular immunotherapy, was approved to treat metastatic castration-resistant prostate cancer in 2010 in the United States. Treatment with sipuleucel-T primes the immune system to target prostate acid phosphatase, which is expressed by prostate cancer cells, potentially leading to lysis of cancer cells. Expanding on previously reported indirect evidence of cell killing with sipuleucel-T treatment, we sought to provide direct evidence of cell lysis through visualization. We used advanced video technology and available samples of peripheral blood mononuclear cells from subjects enrolled in the STAMP trial (NCT01487863). Isolated CD8+ T cells were used as effector cells and cocultured with autologous monocytes pulsed with control or target antigens. Differentially stained effector and target cells were then video recorded during coculture. Here, we present video recordings and analyses of T cells from sipuleucel-T-treated subjects showing-for the first time-direct lysis of cells that express prostate cancer target antigens, prostate acid phosphatase, or prostate-specific antigen
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