cssi/SciSciGPT-SciSciNet huggingface dataset:
Scanning fiber endoscopy: multimodes of guided intervention (Presentation Video)

In this Hot Topics presentation,Eric Seibel discusses his team's work using a scanning-fiber endoscope (SFE) to provide high-contrast imaging. The instrument consists of red-green-blue illumination sources coupled into a single-mode fiber optic that can be scanned in 2D using a piezoelectric tube as an actuator. The output end of the device consists of a quartz cantilever, an asphere lens, and fluorescence detectors coupling high-resolution spectral imaging with a long depth of focus. Compared to current state-of-the-art instruments such as a tethered capsule endoscope with outer diameters on the order of 6mm, the SFE has an outer diameter of only 1.2mm making it suitable for procedures in small ducts and the cardiovascular system. Seibel discusses using the instrument for improving biopsy procedures and diagnostics as well as in stent deployment.
Effectiveness of cooling production with a combined power and cooling thermodynamic cycle

Abstract The combined production of power and cooling with an ammonia–water based cycle is under investigation. Cooling is produced by expanding an ammonia-rich vapor in an expander to sub-ambient temperatures and it is shown that a compromise exists between cooling and work production. A new parameter, termed the effective COP, is used to relate the gain in cooling to the compromise in work production. When the parameter is used to optimize conditions for the rectifier, the effective COP values are good, having values of up to 5. However, when combined operation is compared to work-optimized results, the maximum effective COP values are near 1.1. This implies that per unit of cooling production, nearly equal amounts of work are compromised for combined operation.
Economic History, Pure and Applied

C P. Kindleberger once described economic history as “great fun” but not very useful for understanding what happens in the real world. W. N. Parker, on the other hand, doesn't regard it as at all amusing, but terribly important. Within that range, surely, each of us can locate his own ratio of practicality to enjoyment inherent in the pursuit of economic history. I myself was drawn to the study of economic history, even before I was aware of its existence—in fact, it was my youthful intention to invent the discipline—by two distinct motives. On the one hand, I wanted to enter (or create) a profession in which the work itself would yield intellectual pleasure. At the same time, having just lived through the longest depression in modern times and the most destructive war in history, I wanted to do something that would be useful to society. History, I knew, was interesting. Economics, I assumed, was important. I therefore resolved to give up the study of engineering, which had occupied me briefly before the war, and to create the new discipline of economic history. I was mildly surprised to discover upon enrolling in the Yale Studies for Returning Servicemen that the discipline did, indeed, already exist, and was, furthermore, ably represented at Yale by none other than Harold F. Williamson.
Context change and retrieval difficulty in the list-before-last paradigm

Using the “list-before-last” paradigm (Jang & Huber, Journal of Experimental Psychology: Learning, Memory, and Cognition, 34, 112–127, 2008; Shiffrin, Science, 168, 1601–1603, 1970), we examined whether the difficulty involved in retrieving a previously studied list affects the recall of the current list. Participants studied three lists (L1, L2, and L3), and between L2 and L3 study they either engaged in retrieval of L1 or solved math problems for the same duration of time. After L3 encoding, all participants recalled L2. We examined accurate recall of L2, intrusions from L3, and also the first-response function from L2 across all four experiments. In Experiments 1 and 2, retrieval difficulty was manipulated by presenting participants with variable numbers of letter cues for the L1 words, with some participants receiving more cues than others. In Experiment 1, L1 and L2 words shared the first two letters in common to create potential item interference, whereas in Experiment 2, they did not share common cues. In Experiments 3 and 4, we manipulated retrieval difficulty using a delay manipulation—L1 was encoded 1, 24, or 72 h prior to the session during which L2 and L3 were encoded. In Experiment 3, L1 retrieval involved a cued recall test, whereas in Experiment 4, it involved a free recall test. The results of all of these experiments showed that, as compared to solving math problems, retrieving L1 led to forgetting of L2, reduced intrusions from L3, and reduced first-response functions from L2. However, all of the dependent measures were invariant across the various manipulations of retrieval difficulty. We discuss the results in terms of the context-change interpretation of prior-list retrieval.
A New Shortcut Method for Estimating Economic Base Multipliers

Local and regional development practitioners continue to widely use economic (export) base analysis to assess the strengths and weaknesses of sub-national economies. This paper proposes an alternative means for allocating the total employment of small regions into their basic (export-oriented) and nonbasic (locally-oriented) components, thereby allowing a shortcut calculation of the economic base multiplier. The new regression-based method, which makes use of the Arizona Community Data Set, is designed to supplement, and possibly replace, the well-known assignment, location quotient, and minimum requirements methods. Multipliers based on the four shortcut method are then compared over the time period 1980–2000. All estimates are based on a different data set comprised of nearly 200 communities located in the U.S. Southwest.
Belowground primary production by carbon isotope decay and long-term root biomass dynamics

The isotope decay method of estimating belowground net primary production (BNPP) has the potential to overcome the assumptions and biases associated with traditional methods. Isotope loss through in situ decomposition after pulse-labeling is considered the inverse of production, and turnover times are estimated by regression to time of zero remaining isotope. Method development and estimates of production were previously published using 4 years of data, which showed a clear linear loss rate over time. A slow, distinctly different phase in isotope loss developed 5–10 years postlabeling. We assess reasons for the two-phase loss functions and the implications for estimates of BNPP and compare the isotope decay method with standard coring methods over a 13-year period. Reasons for the two-phase dynamics of carbon 14 (14C) loss could include various biological and/or methodological factors. Results suggest that 14C in soil embedded in roots as they grow, a small proportion of roots that live for a much longer time than the majority of roots, and method of separating roots from soil organic matter may influence estimates of BNPP by isotope methods. Remobilization of label in structural tissue or reuptake of label from the soil did not appear to be responsible for the slow, second phase of loss dynamics. Isotope decay produced more reliable estimates than standard coring methods. Estimates using harvest sum of increments were zero in 6 of 13 years. Thirteen years of root biomass data showed no predictable trend over winter or consistent seasonal pattern, although longer-term cycles were evident. Aboveground:belowground ratios were generally smaller during dry periods, but root biomass was not as responsive as aboveground biomass to annual precipitation.
The Impact of TMT Board Member Control and Environment on Post-IPO Performance

We draw on theories of entrepreneurial firms to explore the impact of top management team (TMT) board control on holding period returns (HPRs). We posit a complex relation between a firm's performa...
Long-term obesity and physical functioning in older Americans.

Americans are becoming obese earlier in their lives, increasing the average exposure to obesity. Nonetheless, the impact of long-term obesity on later life functioning is not well known. We analyzed data from 7258 adults aged 60–79 years from the US 1999–2010 National Health and Nutrition Examination Survey. Respondents were defined as limited if they reported ‘some difficulty’ ‘much difficulty’ or ‘unable to do’ any of the eight functional tasks. Respondents were defined as severely limited if they reported ‘much difficulty’ or ‘unable to do’ any task. Generalized regression models (logistic and Poisson) predicted the relative odds of any limitation, severe limitation, the total number of limitations and each individual limitation as a function of body mass index (BMI) at age 25 years and current BMI. Models were adjusted for age, sex, race/ethnicity and level of education. Overall, being overweight or obese at age 25 years was associated with higher odds of being functionally limited, but these associations were greatly diminished or eliminated after adjustment for current BMI. For example, those obese at age 25 years had 2.38 times the odds (95% confidence interval (CI): 1.77, 3.20) of reporting any functional limitations compared with those normal weight at 25 years, but only 1.28 times the odds (95% CI: 0.93, 1.76) after adjustment for current BMI. For severe limitations, the corresponding results were 2.72 (95% CI: 2.13–3.46) and 1.32 (95% CI:1.00–1.75) before and after adjustment for current BMI. Some associations between obesity at age 25 years and individual tasks remained significant after adjustment for current BMI. We conclude that long-term overweight/obesity are significantly associated with later life functional limitations, though this is largely explained by their strong association with higher levels of later-life BMI. Prevention of additional weight gain for those who are overweight or obese early in life could help mitigate their risk of future loss of functioning.
A Recruitment Model of Quasi-Linear Power-Law Stress Adaptation in Lung Tissue

When lung tissue is subjected to a step in strain, it exhibits a stress adaptation profile that is a power function of time. Furthermore, this power function is independent of the strain, even though the quasi-static stress–strain relationship of the tissue is highly nonlinear. Such behavior is known as quasi-linear viscoelasticity, but its mechanistic basis is unknown. We describe a model of soft tissue rheology based on the sequential recruitment of Maxwell bodies. The model is homogeneous in its elemental constitutive properties, yet predicts both power-law stress relaxation and quasi-linear viscoelasticity even when the stress–strain behavior of the model is nonlinear. The model suggests that stress relaxation in lung tissue could occur via a sequence of micro-rips that cause stresses to be passed from one local stress bearing region to another.
The use of omission training to reduce self-injurious behavior in a retarded child+

Omission training (OM), a response elimination technique which specifies reinforcement for the nonoccurrence of a designated response, was applied on an experimental treatment basis. The subject was a 14-yr-old severely retarded boy with a long-standing self-injurious behavior of headbanging. After a Base Line phase, 50 OM sessions reduced self-injurious responding to a near-zero rate. Accompanying response elimination was the emergence of new, more appropriate social behaviors. During a reversal condition, self-injurious responding occurred at less than half the mean rate emitted during Base Line. During two subsequent behavior probes, no self-injurious responses were emitted. None of the undesirable side effects previously reported with aversive conditioning resulted from the OM procedure. Since positive reinforcement was used throughout, management of the treatment contingencies by institutional personnel and volunteer help was made possible. Suggestions for further study are offered.
Experimental definition of nonaxisymmetric exhaust nozzle plumes

A detailed steady-state five-hole cone probe pressure survey of vectored and nonvectored exhaust plumes was conducted in the AFWAL Trisonic Gasdynamics Facility. Data were collected at a freestream Mach number of 0.5 for a convergent nozzle with an aspect ratio of 11 that was integrated into the wing trailing edge of a halfspan wing/body configuration. Selected cross-sectional pressure and Mach number maps between 0 and 40 nozzle heights downstream are presented. Analysis indicates that the vectored nonaxisymmetric exhaust plume exhibits an accelerated rate of mixing and diffusion, primarily the result of a component of the jet in crossflow rather than the influence of the wing/body flowfield.
Efficient NC Machining Using Off-Line Optimized Feedrates and On-Line Adaptive Control

A combination of off-line feedrate optimization and online adaptive force control is used to maintain a reference peak force during end milling for safe, accurate, and efficient machining. Feedrate optimization algorithms use geometry and force models to calculate feedrates for each tool move, based on a reference peak force. The adaptive controller adjusts the feedrate during machining to maintain the reference peak force. It is the combination of these methods that yields accurate force control, unobtainable with either method by itself. Adaptive control alone is inadequate to handle significant transient cut conditions because of the slow system response time. Optimization algorithms are subject to modeling errors that can lead to significant force errors when cutting. Design parameters for the adaptive controllers are selected using an experimentally validated machining process model. The adaptive controllers are implemented on an open architecture controlled (OAC) 3-axis NC milling machine, and evaluated using three experimental test cases: a sine cut, a prismatic cut, and a corner cut. Feedrates for each cut are first optimized off-line, then used in actual machining with and without controller action. Experimental results demonstrate the ability of the integrated system to effectively regulate peak forces for cutting conditions commonly encountered in end milling operations. In particular, a variable geometry sine cut that initiates chatter shows the advantages of the combined system.Copyright © 2002 by ASME
Mechanism of Rhythmic Synchronous Flashing of Fireflies: Fireflies of Southeast Asia may use anticipatory time-measuring in synchronizing their flashing

In Thailand, male Pteroptyx malaccae fireflies, congregated in trees, flash in rhythmic synchrony with a period of about 560 ± 6 msec (at 28° C). Photometric and cinematographic records indicate that the range of flash coincidence is of the order of ± 20 msec. This interval is considerably shorter than the minimum eye-lantern response latency and suggests that the Pteroptyx synchrony is regulated by central nervous feedback from preceding activity cycles, as in the human "sense of rhythm," rather than by direct contemporaneous response to the flashes of other individuals. Observations on the development of synchrony among Thai fireflies indoors, the results of experiments on phase-shifting in the American Photinus pyralis and comparisons with synchronization between crickets and between human beings are compatible with the suggestion.
Comparison of supercritical fluid extraction and Soxhlet extraction for the determination of polychlorinated biphenyls in environmental matrix standard reference materials

Supercritical fluid extraction (SFE) was compared to traditional Soxhlet extraction for the determination of polychlorinated biphenyl congeners in three standard reference materials: SRM 1941a (Organics in Marine Sediment), SRM 1944 (New York/New Jersey Waterway Sediment) and SRM 2974 [Organics in Mussel Tissue (Mytilus edulis) (Freeze-Dried)]. The concentrations determined using SFE compared well with the certified concentrations for the majority of the polychlorinated biphenyl congeners.
Comparative and categorical spatial judgments in the monkey: “high” and “low”

Adult human subjects can classify the height of an object as belonging to either of the "high" or "low" categories by utilizing an abstract concept of midline that divides the vertical dimension into two halves. Children lack this abstract concept of midline, do not have a sense that these categories are directional opposites, and their categorical and comparative usages of high(er) or low(er) are restricted to the corresponding poles. We investigated the abilities of a rhesus monkey to perform categorical judgments in space. We were also interested in the presence of the congruity effect (a decrease in response time when the objects compared are closer to the category pole) in the monkey. The presence of this phenomenon in the monkey would allow us to relate the behavior of the animal to the two major competing hypotheses that have been suggested to explain the congruity effect in humans: the analog and semantic models. The monkey was trained in delayed match-to-sample tasks in which it had to categorize objects as belonging to either a high or low category. The monkey was able to generate an abstract notion of midline in a fashion similar to that of adult human subjects. The congruity effect was also present in the monkey. These findings, taken together with the notion that monkeys are not considered to think in propositional terms, may favor an analog comparison model in the monkey.
Influence of solution composition and pressure on the rates of oxygen isotope exchange in the system: calcite/1bH2O/1bNaCl at elevated temperatures

Abstract Variations in the extent of oxygen isotope exchange (F, where F = 0 at t = 0; and F = 1 at t = ∞) have been measured in the system calcite/1bH2O/1bNaCl as a function of temperature, pressure and concentration of NaCl. The conditions of these hydrothermal experiments are: T = 300–600°C, P = 1 kbar (0.25 kbar at 300°C; and 0.55, 1 and 2 kbar at 500°C only), m NaCl = 0, 0.1, 0.3, 1 and 4, W/S mass (moles) ratio ∼4, and run time = 211–1956 hr. There is a pronounced increase in the F-values with increasing temperature, salinity, pressure (500°C example only), and degree of grain rounding and regrowth. The rate of change in F is initially steep but tends to flatten out with increasing NaCl at ≳ 1 m. This greater degree of recrystallization is probably related to the enhanced solubility of calcite in the presence of NaCl(aq). Data at 500°C exhibit a trend of increasing F with increasing pressure. Rate constants (log rf in mol m−2 s−1 O) calculated from these data range from a maximum value of −6.75 at 600°C, 1 kbar, 4 m NaCl to a minimum rate of −9.46 at 300°C, 0.25 kbar, 0 m NaCl. Activation energies were calculated for each NaCl concentration at 1 kbar and vary as 15, 16, 19, 20 and 19 kcal mol−1 for 0, 0.1, 0.3, 1 and 4 m NaCl, respectively. Volumes of activation ( ΔV ‡ ) estimated from the 500°C pressure data range from −40 to −9 cm3 mol−1 for 0 and 4 m NaCl, respectively. These data suggest that solvation of ions in solution during the activation step is the dominate process influenced by pressure. Model calculations indicate that isotopic equilibration times are very rapid, on the order of 10′s to 100′s of years at high temperature (> 500°C), high salinity (> 1m) and high pressure (> 1 kbar), depending on the W/S ratio and initial grain size.
Effects of Ethanol on Axon Outgrowth and Branching in Developing Rat Cortical Neurons

Humans exposed prenatally to ethanol can exhibit brain abnormalities and cognitive impairment similar to those seen in patients expressing mutant forms of the L1 cell adhesion molecule (L1CAM). The resemblance suggests that L1CAM may be a target for ethanol, and consistent with this idea, ethanol can inhibit L1CAM adhesion in cell lines and L1CAM-mediated outgrowth and signaling in cerebellar granule neurons. However, it is not known whether ethanol inhibits L1CAM function in other neuron types known to require L1CAM for appropriate development. Here we asked whether ethanol alters L1CAM function in neurons of the rat cerebral cortex. We find that ethanol does not alter axonal polarization, L1CAM-dependent axon outgrowth or branching, or L1CAM recycling in axonal growth cones. Thus, ethanol inhibition of L1CAM is highly dependent on neuronal context.
Why Don't Minorities Join Special Operations Forces?:

Following the Cold War, regional instability and lower-level conflict have increased, bringing with them enhanced roles and responsibilities for the U.S. Special Operations Forces (SOF). As a resul...
The effect of the organophosphate trichlorfon on the neuromuscular blocking activity of atracurium in halothane-anesthetized horses

To determine whether cholinesterase inhibition by an organophosphate would influence atracurium's neuromuscular blockade, six horses were anesthetized and paralyzed with atracurium (total of five injections per horse) on experimental Day 1, then were given trichlorfon (64 mg/kg per os) 6 days later. On Day 7, horses were anesthetized and paralyzed in the same manner as on experimental Day 1. Blood was taken to measure serum cholinesterase activity prior to anesthesia on Days 1 and 7. No significant difference was noted in atracurium's neuromuscular blocking activity between the 2 experimental days (P less than 0.05), despite Day 7 cholinesterase activity that was 16% of pre-trichlorfon values. For atracurium Injections 1 and 2-5, 85 and 43 micrograms/kg of atracurium, respectively, were required to produce a 95-99% reduction in hoof twitch. The time from injection to maximum twitch reduction was approximately 9 min after Injection 1 and 5 min after subsequent injections. Time from injection to maximum twitch reduction was significantly longer for Injection 1 than Injections 2-5 on both experimental days. The time from maximum twitch reduction until 10% recovery was approximately 8 min, with no significant difference between experimental days. The time for twitch recovery from 10 to 75% was approximately 17 min for all injections. Antagonism of atracurium with edrophonium caused the twitch height to return to pre-atracurium strength in approximately 7 min. Edrophonium caused a significant increase in arterial blood pressure. Heart rate change was variable after edrophonium.(ABSTRACT TRUNCATED AT 250 WORDS)
Plasma-activated sintering of aluminum nitride

The use of a new plasma- activated sintering (PAS) process to densify aluminum nitride (AIN) powders to nearly full theoretical density (97 to >99%) in 5 to 10 min was investigated. The process consists of a pulse activation step, followed by sintering at 1730 to 1800 °C using resistance heating in carbon dies. Submicron size (~0.44 μm) AIN powders of low oxygen content (<1 wt%) were consolidated to near full density in both air and vacuum with no sintering aids or binders. Transmission electron microscopy (TEM) examination revealed an equiaxed, submicron grain structure (~0.77 μm) with no apparent pores or intergranular phases. X- ray powder diffraction revealed no secondary crystalline phases.
Does adequate irradiation of the internal mammary chain and supraclavicular nodes improve survival rates

Abstract In all randomized trials of mastectomy alone versus mastectomy and irradiation, the survival rates were not improved with irradiation. In 1977 a randomized trial of patients who were treated with radical mastectomy alone or radical mastectomy followed by irradiation of the peripheral lymphatics with 60 Co showed these results; among the irradiated patients with histologically positive axillary nodes the proportion of patients free of disease was statistically significant, greater than in the control group. At M. D. Anderson Hospital the 10-year survival rates for patients who had peripheral lymphatic irradiation (65.75% with histologically positive axillary nodes) was 56% versus 54% for patients who were treated with radical mastectomy alone (11.5% with histologically positive axillary nodes). The average number of involved nodes per patient was almost the same in the two groups. Because survival rates correlate strongly with the percentage of patients with histologically positive axillary nodes, the survival rate would be expected to be much lower for the irradiated patients. Although the data is not from a randomized trial, it suggests strongly that the irradiation of peripheral lymphatics has been curative in a significant number of patients. A critical review of all the previous randomized trials shows that actually the internal mammary chain nodes and the nodes at the root of the neck, i.e. the nodes that are a direct route of spread of breast cancer, either have been missed completely by the portal arrangement or have received an uncertain dosage.
Coronary artery remodeling in non-contrast CT images

A significant cause of coronary artery disease is the coronary atherosclerosis which leads to stenosis of coronary arteries. It has been shown in recent studies, using intravascular ultrasound and contrast-enhanced CT, that early atherosclerosis causes positive coronary artery remodeling, defined as increases in the cross-sectional area. It is hypothesized that detection of artery remodeling using non-contrast CT can be an important factor in sub-clinical assessment of cardiac risk for asymptomatic subjects. However, measuring remodeling in coronary arteries in non-contrast CT images is a challenging task because coronary arteries are small and the intensity of coronary arteries is similar to that of surrounding tissues. Automatic segmentation algorithms that have been successful in segmenting coronary arteries in contrast-enhanced images do not perform well. To overcome these difficulties, we developed an interactive application to enable effective measurement of coronary artery remodeling in non-contrast CT images. This application is an extension to the 3D Slicer image analysis platform. It allows users to visualize and trace the centerline of arteries in cross sectional views. The artery centerlines are displayed in a three dimensional view overlaid on the original image volume and color-coded according to the artery labels. Using this 3D artery model, the user can sample the cross-sectional area of the arteries at selected points for remodeling assessment. Initial validation has demonstrated the effectiveness of this method. A pilot study also showed positive correlation of large coronary artery remodeling with highest lifetime risks. Further evaluation is underway using larger study size and more measurement points.
Effects of metal-complexing and sulfhydryl compounds on nonphotochemical phytochrome changes in vivo.

Abstract In etiolated seedling tissue, conversion of the red-absorbing form of phytochrome (P R ) to the far-red-absorbing form (P fr ) by a brief red light exposure is followed by rapid loss of P fr and thus of total phytochrome even in subsequent darkness, but no such P fr decay occurs in extracts. In seeking an explanation of this difference, the effects on in vivo P fr decay of compounds routinely used in phytochrome extraction were tested in Avena coleoptiles. Both EDTA and 2-mercaptoethanol inhibit P fr decay in vivo ; EDTA activity increases with increasing pH and is not associated with respiratory inhibition. Glutathione, cysteine, 2,3-dimercaptopropanol, and azide also inhibit. These results and others in the literature suggest that P fr decay is an oxidative metal-dependent process not necessarily involving respiration. Azide levels that prevent decay in Avena and Zea also prevent apparent reversion to the red-absorbing form. Equal inhibition of decay in Pisum is accompanied by constant or increased apparent reversion, suggesting that a true reversion mechanism occurs in this tissue.
Some Reasons for Not Individualizing Typing

(1975). Some Reasons for Not Individualizing Typing. The Journal of Business Education: Vol. 51, No. 2, pp. 71-73.
Nature of the pupillary responses evoked by chromatic flashes on a white background

Color flashes on a steady-white background are classically used to isolate the response of the chromatic (color-opponent), as opposed to achromatic (luminance), channel in psychophysical investigations. The present study shows that pupillary responses evoked by such stimuli behave as if they are composed of functionally separable components. One component has a temporally transient waveform and has an action spectrum that is similar to the spectral sensitivity curve of the psychophysical chromatic channel. The present study discusses the possibility that the pupillary response is mediated by phasic (M-like) neurons and/or by tonic (P-like) neurons.
The value of information in constrained parametric models

We consider the value of information introduced through constraints on the parameters, by showing the Fisher information gain and the resulting Cramer-Rao bound (CRB) reduction. In doing so, we show that the constrained CRB (CCRB) can be found by a transformation of parameters or a projection onto the tangent of the constraint space. Finally, we determine the characteristics of optimal constraints that minimize the trace of the CCRB, thereby attaining the lowest bound on the sum of mean-square errors of unbiased estimators.
C1-equivalence of functions near isolated degenerate critical points in Banach space☆

Abstract We prove two theorems of N. Kuiper by standard methods of the calculus on Banach spaces. C0-sufficiency for Cr-functions of the r-jet of a real valued Cr-function of lowest degree r0 ⩾ 2 on a Hilbert space follows from Kuiper's condition Q(r) also on a Banach space endowed with smooth partitions of unity. A new proof is given of the C1-sufficiency for Cr + p-functions, p ⩾ r − r0, of the r + p-jet of a Q(r)-function on Hilbert space that also holds on Banach space modulo a further condition on the behavior of the function near its degenerate critical point.
Effect of Tunnel Recombination Junction on Crossover Between the Dark and Illuminated Current–Voltage Curves of Tandem Solar Cells

The tunnel recombination junction (TRJ) quality of an amorphous silicon (a-Si)-based tandem junction solar cell can have a significant impact on its performance, where crossover between the dark and illuminated current–voltage curves of a tandem cell indicates a TRJ with poor quality. Therefore, it is critical to be able to understand the TRJ characteristics in order to optimize the tandem solar cell performance. A simulation approach requiring a few data points was used to quantify the TRJ quality. The uniform field collection model was modified to account for parasitic losses due to the TRJ, which are a voltage drop across the TRJ and a series resistance due to the TRJ. Simulation results using the TRJ model are in good agreement with experimental data. The TRJ model can be a useful tool to aid in the optimization of a-Si-based multijunction solar cells.
Activation of Akt signaling in prostate induces a TGFβ-mediated restraint on cancer progression and metastasis

Mutations in the PTEN tumor suppressor gene are found in a high proportion of human prostate cancers, and in mice, Pten deletion induces high-grade prostate intraepithelial neoplasia (HGPIN). However, progression from HGPIN to invasive cancer occurs slowly, suggesting that tumorigenesis is subject to restraint. We show that Pten deletion, or constitutive activation of the downstream kinase AKT, activates the transforming growth factor (TGF)β pathway in prostate epithelial cells. TGFβ signaling is known to have a tumor suppressive role in many cancer types, and reduced expression of TGFβ receptors correlates with advanced human prostate cancer. We demonstrate that in combination either with loss of Pten or expression of constitutively active AKT1, inactivation of TGFβ signaling by deletion of the TGFβ type II receptor gene relieves a restraint on tumorigenesis. This results in rapid progession to lethal prostate cancer, including metastasis to lymph node and lung. In prostate epithelium, inactivation of TGFβ signaling alone is insufficient to initiate tumorigenesis, but greatly accelerates cancer progression. The activation of TGFβ signaling by Pten loss or AKT activation suggests that the same signaling events that have key roles in tumor initiation also induce the activity of a pathway that restrains disease progression.
A generalized method for determining the closed-loop frequency response of nonlinear systems

One of the formidable problems in the area of feedback control concerns the analysis and synthesis of nonlinear systems. Of the several methods available for treating nonlinear systems, one of the more widely used is the sinusoidal response method. Valuable information about the characteristics of nonlinear systems can be obtained from the open-loop frequency response, but the full potential of this method has not been exploited because apparently there is no widely accepted procedure for determining the closed-loop frequency response. This paper describes a method whereby the closed-loop frequency response of an important class of nonlinear systems can be determined easily. Development of this method is dependent upon representing the nonlinear element as a so-called equivalent gain. The method is described and illustrated by analytically determining the closed-loop frequency response of an acceleration-limited system and an error-limited system. The results of the use of this method compare favorably with solutions of the two problems as obtained from an analogue computer. A few of the nonlinear phenomena which can be reasonably approximated by this method are saturation, limiting, backlash, and dead space.
Connectivity in estuarine white perch populations of Chesapeake Bay: evidence from historical fisheries data

The role of complex life cycles in patterns of estuarine habitat use can be evaluated by studying stage-specific changes in abundances between principal habitats. Here, we evaluated how two primary habitats, tidal freshwater (salinity < 3) and brackish water (salinity 3-15), structured juvenile white perch (Morone americana) abundance for eight sub-estuaries of the Chesapeake Bay. In addition, abundances of juveniles in the two primary habitats were related to indices of overall sub-estuary (population) adult abundance. Smaller sub-estuaries (e.g., Patuxent, Nanticoke, Rappahannock) showed higher juvenile abundances in brackish habitats whereas larger systems (e.g., Head of Bay, Potomac, and James) exhibited higher juvenile abundances in freshwater. Within each sub-estuary, we observed strong and positive correlations between freshwater and brackish juvenile abundances. Though adult abundance indices were poor predictors of juvenile abundance in either habitat, a significant amount of variability in adult abundance was explained by juvenile abundances in prior years for most sub-estuaries. The strength of the association varied by sub-estuary and habitat and suggested that juvenile habitats may make disproportionate contributions to the adult population, dependent upon sub-estuary. There were also significant correlations in juvenile abundance between sub-estuaries, indicating interannual synchrony in recruitment among populations. Within sub-estuaries, river discharge did not provide a direct indication of recruitment variability, and currently there is no clear explanation for correlation in juvenile abundances between sub-estuaries. Still, a positive association between correlations in river discharge and significant correlations in juvenile abundances supported previous hypotheses that freshwater flow may be an important factor influencing juvenile abundance, but it is likely that other environmental factors are also driving synchronous fluctuations in juveniles within and between Chesapeake Bay white perch populations.
“AIDS is Money”: How Donor Preferences Reconfigure Local Realities ☆

Summary There is growing concern that the global response to AIDS in sub-Saharan Africa is compromising the region’s human development more broadly. Through a case study of Malawi, I examine the impact of AIDS prioritization by international donors on the country’s NGOs and analyze why AIDS wields such influence on development work. In the last 20 years the Malawian NGO sector has evolved to favor AIDS above all else. AIDS has come to possess prestige and legitimacy that other development sectors are denied. Although guided by good intentions, AIDS efforts may have hindered attempts to address other, non-AIDS, development issues.
Fission probability calculations for heavy-ion induced reactions

The Bohr-Wheeler formalism for nuclear fission has been included in a nuclear evaporation code. The added parameters are the saddle-point level density ${a}_{f}$ and the fission barrier for $J=0, {B}_{f}$. Effects of $^{4}\mathrm{He}$ evaporation are explored by variation of the relevant level density parameter ${a}_{\ensuremath{\alpha}}$. Good fits to fission excitation functions could be achieved but ambiguity remains due to the entrance channel, i.e., the estimated critical angular momentum and the $\ensuremath{\alpha}$ evaporation probability. Three different systems have been investigated: $^{182}\mathrm{W}$ + $^{12}\mathrm{C}$\ensuremath{\rightarrow}$^{194}\mathrm{Hg}$, $^{175}\mathrm{Lu}$ + $^{12}\mathrm{C}$\ensuremath{\rightarrow}$^{187}\mathrm{Ir}$, and $^{174}\mathrm{Yb}$ + $^{12}\mathrm{C}$\ensuremath{\rightarrow}$^{186}\mathrm{Os}$. In this framework the measurement of cross sections for $\ensuremath{\alpha}$ emission and evaporation residues, as well as that for fission, would suffice to fix the important parameters.NUCLEAR REACTIONS, FISSION $^{182}\mathrm{W}(^{12}\mathrm{C},f)$; $^{175}\mathrm{Lu}(^{12}\mathrm{C},f)$; $^{174}\mathrm{Yb}(^{12}\mathrm{C},f)$; calculated fission excitation functions; dependence on ${l}_{\mathrm{crit}}$, $\frac{{a}_{f}}{{a}_{n}}$, $\frac{{a}_{\ensuremath{\alpha}}}{{a}_{n}}$, ${B}_{f}$.
Current-voltage relation of a centrifugally confined plasma

Observations of Jupiter's auroral regions indicate that electrons are accelerated into Jupiter's atmosphere creating emissions. The acceleration of the electrons intimate that parallel electric fields and field-aligned currents develop along the flux tubes which connect the equatorial plane to the areas with auroral emission. The relationship between the development of parallel electric fields and the parallel currents is often assumed to be the same as that on Earth. However, the relationship is significantly different at Jupiter due to a lack of plasma at high latitudes as large centrifugal forces caused by Jupiter's fast rotation period (about 9.8 h) constrain the magnetospheric plasma to the equatorial plane. We use a 1-D spatial, 2-D velocity space Vlasov code which has been modified to include centrifugal forces to examine the current-voltage relationship that exists at Jupiter. In particular, we investigate this relationship at a distance of 5.9 Jovian radii, the orbital radius of Io, which is coupled with the auroral spot and Io wake auroral emissions. Copyright 2009 by the American Geophysical Union.
A visualized observation of calcium-dependent gelsolin activity upon the surface coverage of fluorescent-tagged actin filaments

Abstract Gelsolin regulates the dynamics of F-actin by binding to F-actin to sever and cap. In the present study, a novel approach is introduced to observe gelsolin activity through the coverage of surface-bound F-actin. Gelsolin was immobilized on streptavidin coated surface using biotinylation and, as a result, the interaction between gelsolin and F-actin was visualized. Consequently, the coverage of F-actin reflects the activity of gelsolin as a function of free Ca2+ concentrations. In order to prevent non-specific binding of F-actin, the combinations of BSA and Tween-20 as blocking agents were investigated. Moreover, the measurement of the length of F-actin with actin–gelsolin mixtures at various ratios provided the verification of gelsolin activity after biotinylation. The data shows the increase in Ca2+ concentration leads to a proportional increase in F-actin coverage, giving to half-maximal coverage at ~2.9 μM. Furthermore, the length of bound F-actin was found to decrease along with increasing Ca2+ concentration, and full-length F-actin was rarely observed. This may suggest that severing and capping activities of gelsolin occur without more additional Ca2+ for subsequent activation after full-length gelsolin binds to a side of F-actin. This finding may provide a key to understand gelsolin activity.
N-linked glycoside/glucuronide conjugates of retinoids: acitretin

Abstract Glucuronide conjugates of retinoids have been found to be active metabolites of the parent molecules. However, O -acylglucuronide retinoids are liable to hydrolysis and retinoid ring oxidation. We have prepared stable N -linked glycosides of acitretin in efforts to overcome these problems. The synthesis and preliminary biological studies of the analogs are reported.
Colony Founding by Queens of the Obligatory Slave-making Ant, Polyergus breviceps: The Role of the Dufour's Gland1

We conducted laboratory studies of the process by which newly-mated queens of the slave-making ant Polyergus breviceps invade colonies of their host species Formica gnava, kill the resident Formica queen, and appropriate the brood. The aggressive behavior of resident Formica workers towards the invading Polyergus queen subsides shortly after the Formica queen is killed. To elucidate the chemical basis for the reduction in aggression, we prepared extracts of Dufour's, pygidial, and poison glands from Polyergus queens. Workers of the harvester ant Pogonomyrmex occidentalis were daubed with these extracts, and introduced into dishes containing Formica workers. Only the Dufour's secretion protected the intruding ants from incessant aggression by Formica. Preliminary studies also show that the enlarged, bilobed Dufour's gland of the Polyergus queen decreases in size shortly after mating, when developing oocytes occupy a significant portion of the queen's gaster.
Job queues, certification status, and the education labor market

This research explores the interaction between training programs and certification status in one education labor market to examine the micro-level interactions that shape the recruitment process. Using job queue theory, it is found that the information available to novice teachers operates to stratify and shape their worksite choices in addition to stratifying workers by their certification status. Traditionally trained teachers use the formal and informal knowledge garnered during training to identify preferred worksites, citing poverty levels, student achievement, and the administration as important factors in the decision-making process. Conversely, alternatively trained teachers are channeled into disadvantaged schools and, constrained by limited occupational knowledge, select a worksite based on personal interactions. Accountability policies and teacher training programs interact to stratify schools and teachers in the education labor market.
Evaluating systems change in a juvenile justice reform initiative

Abstract Evaluating comprehensive, interagency initiatives to reform human services systems presents substantial challenges to traditional research models. Outcomes are observed at the system level rather than the individual level, and the validity of study results may be challenged on a variety of dimensions, particularly small sample sizes and measurement error. We report the results of a cross-site evaluation of the first phase of Reclaiming Futures, a five-year effort to improve services and interventions for justice-involved youth in 10 communities across the United States. We present the evaluation findings and discuss implications for similar research endeavors. The methods used in this study may be useful for other system-level evaluation efforts. A social network analysis analyzes changes in the size, density, and cohesiveness of stakeholder networks. Bivariate models test for associations between Reclaiming Futures implementation and key stakeholder perceptions of effective system change. Multivariate models are used to explore selection effects on item response. In general, we find positive correlations between successful implementation of Reclaiming Futures and indicators of effective and efficient system change.
Synaptic transmission reversibly conditioned by single-gene mutation in Drosophila melanogaster.

ONE way to advance current physiological and biochemical understanding of the mechanism of synaptic transmission at the molecular level is to alter synaptic function by means of single gene mutations. Among the various behavioural mutants of Drosophila melanogaster, those which express a mutant phenotype only in certain conditions and otherwise behave normally are of particular interest. If the mutant phenotype appears at the synapse, the mutant might enable a reversible modification of synaptic function by way of experimentally controlling the expression of the mutant phenotype. Such a mutant would provide a useful tool for the study of synaptic function.
Epigenetics: How to lose a tail

Everyone carries some baggage they would like to lose. For the histone protein H3, that baggage is a chunk of its tail, which when clipped off affects the expression of genes with which the histone is associated.
Application of optimal control theory to flexible robotic manipulations

Abstract The dynamic equatios of a single link flexible robotic manipulator and the measurements are formulated. The observer and the control law are derived based on optimal control theory. The numerical results of several cases obtained through computer simulation are presented here. The issues of nonlinearity and sampling rate, and the effects of gravity, white noises, and damping are investigated. The feasibility of real-time control of flexible robotic manipulators is discussed.
Abstract 4440: Identification and characterization of small molecule inhibitors that radiosensitize K-RAS mutant rectal cancers.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Around 40% of rectal cancers harbor activating K-RAS mutations, and these mutations are associated with resistance to chemoradiotherapy. We aimed to identify small molecule inhibitors (SMIs) that synergize with ionizing radiation (IR) (“radiosensitizers”) that could be incorporated into current treatment strategies for K-RAS mutant locally advanced rectal cancer (LARC) patients. We first optimized a high-throughput assay for measuring individual and combined effects of SMIs and IR that produces similar results to the gold standard colony formation assay. Using this screening platform and K-RAS mutant rectal cancer cell lines, we tested SMIs targeting diverse signaling pathways for radiosensitizing activity and then evaluated our top hits in follow-up experiments. The two most potent radiosensitizers were the Chk1/2 inhibitor AZD7762 and the PI3K/mTOR inhibitor BEZ235. The chemotherapeutic agent 5-fluorouracil (5-FU), which is used to treat LARC, synergized with AZD7762 and enhanced radiosensitization by AZD7762 but not by BEZ235. This study is the first to compare different SMIs in combination with IR for the treatment of K-RAS mutant rectal cancer, and our findings suggest that Chk1/2 inhibitors should be evaluated in new clinical trials for LARC. Citation Format: Laura B. Kleiman, Angela Krebs, Stephen Kim, Theodore S. Hong, Kevin M. Haigis. Identification and characterization of small molecule inhibitors that radiosensitize K-RAS mutant rectal cancers. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4440. doi:10.1158/1538-7445.AM2013-4440