cssi/SciSciGPT-SciSciNet huggingface dataset:
The effects of axial diffusion and permeability barriers on the transient response of tissue cylinders. II. Solution in time domain.

A mathematical description of transient mass transfer in a Krogh tissue cylinder, for which a solution in transform space was presented previously, is solved in the time domain. The solution is found in the form of an expansion in terms of the eigenfunctions of a non-self-adjoint differential operator, with the eigenvalues being found by way of a computational scheme which makes use of the known characteristics of the constitutive compartments of the system. The solution is compared with previous solutions of both a complete and an approximate nature, and two modifications of the single-phase axial dispersion model are found to be especially useful: the previously-used flow-limited approximation is satisfactory for highly permeable solutes, while the apparently novel barrier-limited approximation is accurate for poorly permeable solutes at the early times of most experimental interest. Although the neglect of axial diffusion does not affect the qualitative nature of the solution, e.g. in predicting a bimodal response curve, significant discrepancies shed doubt on this practice when truly impulsive inputs are used. The results obtained raise several questions regarding existing approaches to interpretation of indicator dilution experiments. These include the use of extraction ratios and of exponential extrapolation of the tails of response curves.
Mechanisms of fatigue differ after low- and high-force fatiguing contractions in men and women

The magnitude of failure in voluntary drive after fatiguing contractions of different intensities in men and women is not known. The purpose of this study was to compare the time to task failure and voluntary activation of men and women for a sustained isometric contraction performed at a low and high intensity with the elbow flexor muscles. Nine men and nine women sustained an isometric contraction at 20% and 80% of maximal voluntary contraction (MVC) force until task failure during separate sessions. The men had a shorter time to failure than women for the 20% but not the 80% MVC task. Voluntary activation was reduced to similar levels for the men and women at the end of the fatiguing contractions but was reduced less after the 80% MVC task than the 20% MVC contraction. Twitch amplitude was reduced similarly at task failure for both sexes and to similar levels at termination of the 20% and 80% MVC tasks. The rate of change in mean arterial pressure was the main predictor of time to failure for the low-force sustained contraction. These results suggest that women experienced greater muscle perfusion, less peripheral fatigue, and a longer time to task failure than men during the low-force fatiguing contraction. However, the low-force task induced greater central fatigue than the high-force contraction for both men and women. Thus, low-force, long-duration fatiguing contractions can be used in rehabilitation to induce significant fatigue within the central nervous system and potentially greater neural adaptations in men and women.
Analysis of aperture radiation from an axially slotted circular conducting cylinder using geometrical theory of diffraction

The wedge-diffraction theory in combination with the creeping wave theory is used to compute the radiation pattern of an axial slot on a circular conducting cylinder. The slot is excited by a parallel-plate waveguide operating in the TEM-mode. The total field in the "lit" region is obtained by the superposition of the wedge-diffracted and creeping wave fields. The total field in the "shadow" region is obtained solely from the creeping wave contribution.
An Empirical Study of the Behavior of Active Learning for Word Sense Disambiguation

This paper shows that two uncertainty-based active learning methods, combined with a maximum entropy model, work well on learning English verb senses. Data analysis on the learning process, based on both instance and feature levels, suggests that a careful treatment of feature extraction is important for the active learning to be useful for WSD. The overfitting phenomena that occurred during the active learning process are identified as classic overfitting in machine learning based on the data analysis.
[K+] dependence of open-channel conductance in cloned inward rectifier potassium channels (IRK1, Kir2.1)

Potassium conduction through unblocked inwardly rectifying (IRK1, Kir2.1) potassium channels was measured in inside-out-patches from Xenopus oocytes, after removal of polyamine-induced strong inward rectification. Unblocked IRK1 channel current-voltage (I-V) relations show very mild inward rectification in symmetrical solutions, are linearized in nonsymmetrical solutions that bring the K+ reversal potential to extreme negative values, and follow Goldman-Hodgkin-Katz constant field equation at extreme positive E alpha. When intracellular K+ concentration (KIN) was varied, at constant extracellular K+ concentration (KOUT) the conductance at the reversal potential (GREV) followed closely the predictions of the Goldman-Hodgkin-Katz constant field equation at low concentrations and saturated sharply at concentrations of > 150 mM. Similarly, when KOUT was varied, at constant KIN, GREV saturated at concentrations of > 150 mM. A square-root dependence of conductance on KOUT is a well-known property of inward rectifier potassium channels and is a property of the open channel. A nonsymmetrical two-site three-barrier model can qualitatively explain both the I-V relations and the [K+] dependence of conductance of open IRK1 (Kir2.1) channels.
LEGEND AND THE AGENDA FOR URBAN REFORM: A Response to Daniel J. Monti

: Fascination with the language of economics, combined with an overwrought/ear about engaging in speculation that fellow social scientists will deem too soft, has depleted and made brittle the lexicon with which scholars try to account for central city decline and from which they hope to construct remedies. Monti's paper performs a service by building on the concept of local citizenship and by introducing the concept of legends into the serious dialogue about urban redevelopment. Citizenship is part of the glue that holds communities together when models premised on narrow self-interest predict fragmentation and flight. Urban legends may provide a window into the psychosocial processes that have eroded the optimism and sense of shared interests that are prerequisites to a collective movement for urban revitalization. By overinvesting in the redemptive power of urban legend, however, Monti risks providing false encouragement to those who would like to believe that the deep problems affecting our cities can be washed away without hard work, resources, and political will.
Wave–matter interactions in epsilon-and-mu-near-zero structures

Unusual effects arise when a material’s permittivity or permeability approach zero, a scenario that can be readily engineered in metamaterials. This study explores the regime wherein both these quantities go to zero and the electric and magnetic fields effectively decouple while remaining temporally dynamic.
Reply to the letter to the editor: does the use of ultrasound affect contamination of musculoskeletal injections sites?

To the editor, We would like to thank Dr. Ata and colleagues for their interest in our recent article [5] that investigates the effect of ultrasound guidance on skin contamination at injection sites. Their response highlights the variety of techniques with which musculoskeletal injections are performed, particularly in the presence of ultrasound guidance. This has particular relevance when considering the prevention of iatrogenic infection, as even in the absence of ultrasound guidance, there is marked variability amongst practitioners in the antiseptic precautions taken. To this end, Charalambous et al. [1] reported that more than half of practitioners performing injections do not wear gloves and few isolate the injection field with sterile towels. To our knowledge, there is no similar report that summarizes antiseptic practices taken in the presence of ultrasound guidance. Although such a study would be useful, it is our own experience that many practitioners have dissimilar techniques with varying levels of precautionary methods taken to prevent contamination. The indirect technique of ultrasound guidance, in which the relevant anatomy is visualized and then the probe removed prior to needle introduction, mitigates the potential for contamination of the injection site, as the area can be disinfected after probe removal but prior to injection. The direct technique, however, requires the probe to be in constant, close proximity to the needle and thereby increases the likelihood of contamination of the injection site with transmission gel. This technique is commonly reported in the literature and most popular in our experience [2, 4]. Although more challenging, this direct approach also allows for recording of images that demonstrates the location of the needle in the intended structure, which is often needed or at least helpful for appropriate procedure coding [3]. The findings of our study are most salient to establishing safe practices for preventing contamination when using the direct approach and support using a disinfected probe and sterile ultrasound transmission gel, and perhaps most importantly, disinfecting a large skin area that includes surfaces where the probe will be placed in addition to the immediate injection site.
Separation Mechanisms in Gel Permeation Chromatography

Abstract This paper presents flow rate studies, vacancy chromatography, and a static mixing experiment. Data obtained on an unpacked column (a straight tube) and on a column packed with nonporous glass beads are also reported. The results reveal that peak dispersion in GPC arises mainly from lateral diffusion in the stationary phase (permeation in and out of the porous substrate) and from lateral diffusion in the mobile phase. GPC peak separation is mainly dominated by the process of steric exclusion. Pore size distribution data obtained on Bio-Rad porous glass are shown to illustrate the preference of random coil theories over theories of the equivalent sphere in the interpretation of steric exclusion of flexible polymers. The data are discussed in terms of Herman's diffusion theory and Cassasa's exclusion theory.
The molecular composition of dense interstellar clouds

Presented in this paper is an ab initio chemical model for dense interstellar clouds that incorporates 598 grain surface reactions, with small grains providing the reaction area. Gas-phase molecules are depleted through collisions with grains. The abundances of 372 chemical species are calculated as a function of time and are found to be of sufficient magnitude to explain most observations. Peak abundances are achieved on time scales of the order of 100,000 to 1 million years, depending on cloud density and kinetic temperature. The reaction rates for ion-molecule chemistry are approximately the same, indicating that surface and gas-phase chemistry may be coupled in certain regions. The composition of grain mantles is shown to be a function of grain radius. In certain grain-size ranges, large molecules containing two or more heavy atoms are more predominant than lighter 'ices' - H2O, NH3, and CH4. It is possible that absorption due to these large molecules in the mantle may contribute to the observed 3-micron band in astronomical spectra.
INDIRECT ELECTRO-OXIDATION OF PYRITE SLURRIES: REACTION RATE STUDIES

Pyrite slurry oxidation in the anode compartment of an electrolysis cell was observed to occur via an autocatalytic pathway. The rates of pyrite-assisted water electrolysis were enhanced by the addition of anionic mediators of Fe3+, Ce4+ and V5+. Electrolysis was conducted in acidic electrolytes at electrode potential less than that required for ordinary water electrolysis. A mathematical model for pyrite oxidation is proposed; the chemical rate constant is found to follow the expression: Activation energy of 22.3 kcal mol-1 is obtained for pyrite oxidation in 1 M H2SO4.
Koru: Teaching Mindfulness to Emerging Adults

Although there is much interest in teaching mindfulness to college students and other emerging adults, traditional methods of teaching mindfulness and meditation are not always effective for reaching this age group. Koru is a program, developed at Duke University, that has been specifically designed with the developmental characteristics of emerging adults in mind.
Renin-Angiotensin Gene Polymorphisms and Neurohormonal Inhibition

Analyses of polymorphisms in the renin-angiotensin system may never completely predict responsiveness to pharmacotherapy that blocks angiotensin-converting enzyme or the angiotensin receptor type 1. However, the pharmacogenetic studies that have been conducted to date are intriguing, and they illustrate the potential benefit of designing larger genome-wide clinical studies. Such studies will continue to define the role of renin-angiotensin pharmacogenetics in patients with heart failure due to underlying cardiac dysfunction.
Association of hepatitis C virus infection with mortality and graft survival in kidney-pancreas transplant recipients.

Background.Although most studies have not demonstrated decreased patient or graft survival in kidney-alone allograft recipients infected with hepatitis C virus (HCV), the impact of HCV infection on patient and graft survival in HCV-infected kidney-pancreas recipients has not been studied.Methods.We
Generalized cross-validation as a stopping rule for the Richardson-Lucy algorithm.

The Richardson-Lucy (R-L) algorithm has been widely used to restore degraded astronomical images. This algorithm is nothing more than the expectation-maximization (EM) algorithm applied to Poisson data. The R-L method is iterative in nature and converges to a (possibly local) maximum of the likelihood function. Unfortunately, because of the ill-conditioned nature of the problem, this maximum likelihood estimate may actually be a very poor restoration. One way to prevent degradation of the restoration is to stop the iteration before it reaches convergence. A number of methods have been proposed for determining the optimal stopping point-the point that provides the best trade-off between restoring the image and amplifying the noise. Cross-validation (CV) has recently been proposed as an advantageous method for determining the optimal stopping point. We propose a different form of CV based on generalized cross-validation (GCV) that overcomes some of the difficulties of CV. We derive a GCV-based criterion for the R-L algorithm that can be efficiently evaluated at each iteration. We present examples displaying the power of the stopping rule and discuss the abilities and shortcomings of the method.
Vitamin C treatment reduces elevated C-reactive protein

Plasma C-reactive protein (CRP) is an inflammatory biomarker that predicts cardiovascular disease. We investigated whether vitamins C or E could reduce CRP. Healthy nonsmokers (n=396) were randomized to three groups:1000 mg/day vitamin C, 800 IU/day vitamin E, or placebo, for two months. Median baseline CRP was low, 0.85 mg/L. No treatment effect was seen when all participants are included. However, significant interaction was found, indicating that treatment effect depends on baseline CRP concentration. Among participants with CRP indicative of elevated cardiovascular risk (≥1.0 mg/L), vitamin C reduced median CRP by 25.3% vs. Placebo (p=0.02), (median reduction in the vitamin C group, 0.25 mg/L, 16.7%). These effects are similar to those of statins. The vitamin E effect was not significant. In summary, treatment with vitamin C but not E significantly reduced CRP among individuals with CRP ≥ 1.0 mg/L. Among the obese, 75% had CRP ≥ 1.0 mg/L. These data extend previous results in smokers, and identify CRP levels susceptible to reductions. Research is needed to determine whether reducing this inflammatory biomarker with vitamin C could reduce diseases associated with obesity. But research on clinical benefits of antioxidants should limit participants to persons with elevations in the target biomarkers.
Doppler tissue imaging during supine and upright exercise in healthy adults.

Doppler tissue imaging variables were measured in 18 healthy men and women during supine bicycle stress exercise and upright exercise treadmill testing. From a color Doppler tissue imaging cineloop, tissue velocities in basal and mid segments of the standard 3 apical views during rest and peak exercise were assessed. Compared segments were adjusted for double product, and peak variables were compared using the paired t test. Peak systolic velocity and strain rate increased with both forms of exercise ( P P
256- and 320-row coronary CTA: is more better?

This editorial refers to ‘The diagnostic accuracy of 256-row computed tomographic angiography compared with invasive coronary angiography in patients with suspected coronary artery disease’, by S.-P. Chao et al. doi:10.1093/eurheartj/ehq072 and ‘Diagnostic accuracy of 320-row multidetector computed tomography coronary angiography in the non-invasive evaluation of significant coronary artery disease’, by F.R. de Graaf et al. doi:10.1093/eurheartj/ehp571 The gold standard for evaluating coronary anatomy is invasive coronary angiography because of excellent spatial resolution. Significant advances in coronary CT angiography (CCTA) using multiple-row detectors (MDCT) have made it possible to evaluate the heart and coronary arteries non-invasively. The development of MDCT, beginning with four detector rows and improving to the current clinical standard of 64 rows, allows imaging of the heart in a sufficiently short breath hold as to minimize motion artefacts. However, research with much higher numbers of detector rows, such as the 256- and 320-row MDCT now makes it possible to image the entire heart in one or two heart beats. With 64-row and higher MDCT, image quality is influenced by the cardiac volume imaged per gantry rotation, the high number of thin images obtained, as well as spatial and temporal resolution. Furthermore, to image a beating heart, high temporal resolution is needed which is determined by the gantry rotation, use of prospective or retrospective electrocardiographic (ECG) gating, and whether the image reconstruction requires significant data overlap during scanning. A further challenge of MDCT is obtaining diagnostic quality images with low radiation doses. Many factors influence radiation dose with MDCT, including type of ECG gating, ECG dose modulation where the tube current voltage is low outside of diastole, table pitch, scan time, and adjustments in tube current for patient size and tube voltage (kV). Two studies of CCTA have been published recently; Chao et al. 1 use a 256-row and …
Creep and superplasticity in a spray-cast aluminum alloy processed by ECA pressing

Abstract A commercial spray-cast aluminum 7034 alloy, having a composition of Al–11.5% Zn–2.5% Mg–0.9% Cu–0.2% Zr, was processed by equal-channel angular pressing (ECAP) at a temperature of 473 K to reduce the grain size from ∼2.1 to ∼0.3 μm. Microstructural observations revealed a breaking of the rod-like MgZn 2 precipitates during ECAP. Static annealing showed the ultrafine grain size was reasonably stable up to a temperature of 673 K. Tensile and creep tests were conducted using specimens cut from the unpressed bars and from billets processed by ECAP. In tensile testing at 673 K, the results on the as-pressed alloy show a potential for achieving high superplastic elongations to failure of >1000% at stain rates at and above 10 −2 s −1 . In creep testing at 473 K, the creep rates recorded for the as-pressed samples were significantly faster, by about two orders of magnitude, than for the unpressed alloy.
Intestinal polymeric immunoglobulin receptor is affected by type and route of nutrition.

Background: Secretory immunoglobulin A (SIgA) prevents adherence of pathogens at mucosal surfaces to prevent invasive infection. Polymeric immunoglobulin receptor (pIgR) is located on the basolateral surface of epithelial cells and binds dimeric immunoglobulin A (IgA) produced by plasma cells in the lamina propria. This IgA-pIgR complex is transported apically, where IgA is exocytosed as SIgA to the mucosal surface. Our prior work shows that mice fed intragastric (IG, an elemental diet model) and IV parenteral nutrition (PN) solution have reduced intestinal T and B cells, SIgA, and interleukin-4 (IL-4) compared with mice fed chow or a complex enteral diet (CED). Prior work also demonstrates a reduction in IgA transport to mucosal surfaces in IV PN–fed mice. Because IL-4 up-regulates pIgR production, this work studies the effects of these diets on intestinal pIgR. Methods: Male Institute of Cancer Research (ICR) mice were randomized to chow (n = 11) with IV catheter, CED (n = 10) or IG PN (n = 11) via gast...
Reliability-Based Design Optimization With Confidence Level for Non-Gaussian Distributions Using Bootstrap Method

For reliability-based design optimization (RBDO), generating an input statistical model with confidence level has been recently proposed to offset the inaccurate estimation of the input statistical model with Gaussian distributions. For this, the confidence intervals of mean and standard deviation are calculated using the Gaussian distributions of input random variables. However, if the input random variables are non-Gaussian, the use of the Gaussian distributions of input variables will provide inaccurate confidence intervals, and thus, yield undesirable confidence level of the reliability-based optimum design meeting the target reliability βt . In this paper, the RBDO method using the bootstrap method, which does not use the Gaussian distributions of input variables to calculate the confidence intervals of mean and standard deviation, are proposed to obtain the desirable confidence level of output performance for non-Gaussian distributions.Copyright © 2010 by ASME
The development of scientific reasoning skills in conjunction with collaborative writing assignments: An interpretive study of six ninth-grade students

In this investigation, three classes of ninth-grade general science students participated in a collaborative report-writing intervention. The purpose of this portion of the study was to evaluate students' collaboratively written laboratory reports for evidence of the use of scientific reasoning skills and to document qualitative changes in reasoning skill use over time. The participants in the study were 6 ninth-grade students, representing three collaborative writing pairs. During the intervention, students wrote 10 laboratory reports over a 4.5-month period. The author and classroom teacher designed report guideline prompts to scaffold students in the use of relevant scientific reasoning skills. The results indicated that students used reasoning skills to assess their current models of scientific understanding, make observations, interpret the meaning of results, and generate new models based on their data and relevant information. Participants showed the most improvement in writing that reflected the reasoning skills of (a) selecting and processing textbook passages, (b) drawing conclusions and formulating models, and (c) comparing/contrasting. Over time, participants improved their ability to compose explanations that represented a synthesis of prior knowledge, activity observations, and other sources of information. Collaborative writing encouraged students to construct their own understandings of science concepts by creating an environment in which thinking, reasoning, and discussion were valued.
Maximum principle gradient estimates for the capillary problem

On utilise le principe de maximum pour estimer le gradient des solutions du probleme capillaire non parametrique a n dimensions. On demontre que des solutions sont continues de Lipschitz dans certains domaines singuliers
Evolution of Thermal Reaction Norms for Growth Rate and Body Size in Ectotherms: An Introduction to the Symposium

Although the size of an organism is influenced by many features of its environment, the relationship between temperature and body size has captivated generations of biologists. From the renowned observations by Bergmann (1847) to the phylogenetic comparative studies by our contemporaries (e.g., Ashton et al., 2000), evidence of a widespread relationship between temperature and adult body size has been offered repeatedly for various groups of animals. This relationship, which has come to be known as Bergmann’s rule, is an increase in the body size of a species with a decrease in environmental temperature. Bergmann’s rule was inspired initially by endotherms, but numerous species of ectotherms also exhibit Bergmann’s clines in body size (de Queiroz and Ashton, 2004). Furthermore, lab studies have shown that a higher temperature during ontogeny generally results in a smaller size at maturity (Atkinson, 1994, 1995). This thermal plasticity of size could be one of the most taxonomically widespread patterns of phenotypic variation, having been observed in bacteria, protists, plants and animals. Moreover, the correspondence between trends in artificial and natural environments suggests that thermal plasticity causes some of the geographic variation in body size within ectothermic species. Both proximate and ultimate explanations for temperature-size relationships have been proposed, debated, rejected and revised (Berrigan and Charnov, 1994; Sibly and Atkinson, 1994; Perrin, 1995; Sevenster, 1995; Atkinson, 1996; Atkinson and Sibly, 1996; van der Have and de Jong, 1996: Van Voorhies, 1996; Partridge and Coyne, 1997; Angilletta and Dunham, 2003; reviewed by Atkinson and Sibly, 1997). Still, there is little consensus on the key mechanisms that are responsible these relationships. For example, Van Voorhies (1996) proposed that Bergmann’s clines were caused by increasing cell size with decreasing developmental temperature, but Partridge and Coyne (1997) pointed out that larger bodies are not necessarily achieved by having larger cells. Attempts to secure an ultimate explanation for temperature-size relationships have met with similar difficulties; indeed, few models of life-history evolution predict relatively large sizes
Interleukin-6 decreases senescence and increases telomerase activity in malignant human cholangiocytes.

Abstract Background/aims Cellular senescence results in irreversible growth arrest. In malignant cells, senescence is prevented by maintenance of chromosomal length by telomerase activity. Telomerase activity is increased in malignant, but not in normal cholangiocytes. Interleukin-6 (IL-6) is an autocrine promoter of cholangiocarcinoma growth. Our aims were to assess the relationship between IL-6 activated p38 mitogen-activated protein kinase (MAPK) pathways and senescence in malignant cholangiocytes. Methods Cell senescence and telomerase activity was assessed in Mz-ChA-1 malignant human cholangiocytes. The effect of inhibitors of p38 MAPK and telomerase activity on cell proliferation was assessed, and the interaction between these inhibitors was quantitated by median effects analysis. Results Mz-ChA-1 cells rapidly underwent senescence during repeated passaging. IL-6 increased telomerase activity and decreased cellular senescence during repeated passaging. However, basal telomerase activity was increased by inhibition of p38 MAPK. Inhibition of telomerase activity decreased IL-6 induced proliferation and had a synergistic effect with p38 MAPK inhibitors. Thus, IL-6 increases telomerase activity independent of p38 MAPK signaling and maintenance of telomerase activity promotes cholangiocarcinoma growth. Conclusion Enhanced telomerase activity in response to IL-6 stimulation can prevent cellular senescence and thereby contribute to cholangiocarcinoma growth. Inhibition of telomerase activity may therefore be therapeutically useful in biliary tract malignancies.
White Matter Structural Integrity in Healthy Aging Adults and Patients With Alzheimer Disease: A Magnetic Resonance Imaging Study

Background Imaging and postmortem studies suggest that frontal lobe white matter (FLWM) volume expands until about the age of 44.6 years and then declines. Postmortem evidence indicates that the structural integrity of myelin sheaths deteriorates during normal aging, especially in late myelinating regions such as the frontal lobes. Objectives To assess the integrity of FLWM by magnetic resonance imaging and, thus, to provide an important index of brain aging and its relationship to Alzheimer disease (AD). Design Cross-sectional study. Setting Two metropolitan university hospitals and AD research centers. Participants Two hundred fifty-two healthy adults (127 men and 125 women), aged 19 to 82 years, and 34 subjects with AD (16 men and 18 women), aged 59 to 85 years. Main Outcome Measure Calculated transverse relaxation rate (R 2 ) of the FLWM (an indirect measure of the structural integrity of white matter). Results As expected from prior imaging data on FLWM volume, the quadratic function best represented the relationship between age and the FLWM R 2 ( P 2 increased until the age of 38 years and then declined markedly with age. The R 2 of subjects with AD was significantly lower than that of a group of healthy control subjects who were of similar age and sex ( P Conclusions The R 2 changes in white matter suggest that the healthy adult brain is in a constant state of change, roughly defined as periods of maturation continuing into middle age followed by progressive loss of myelin integrity. Clinically diagnosed AD is associated with more severe myelin breakdown. Noninvasive measures, such as the determination of the R 2 , may have the potential to track prospectively the trajectory of deteriorating white matter integrity during normal aging and the development of AD and, thus, may be a useful marker for medication development aimed at the prevention of AD.
The multiple testis in diemyctylus

A study of the development and seasonal changes of the testis in Diemyctylus viridescens shows that accessory testicular lobes arise as follows: Emptying of the caudal zone of the testis at mating is followed by degeneration of the lobules (tubules) of that region, reducing it to a slender cord consisting chiefly of duct system and residual spermatogonia. A regeneration of lobules at the distal end of this cord later gives rise to the second or accessory lobe. Accessory lobes develop in immature males after a similar reduction of the caudal end of the testis through spermatogonial degeneration or an abortive spermatogenesis. The caudal germ-cell cord thus formed is comparable to that resulting from extrusion of spermatozoa, and the development of new lobules at the distal end of this cord gives rise to a second lobe as in adult males. There is no evidence of the formation of a multiple testis by outgrowths from the primary lobe or by the junction of several lobes originally separate. A multiple testis occurs in Urodele species exhibiting two peculiarities of the spermatogenetic pattern: (1) a slow spermatogenetic wave and, (2) delayed regeneration of lobules emptied at mating or by degeneration of their germ cells. The number of lobes is correlated with the age of the individual. In Diemyctylus under 6 cm. the first accessory lobe has not yet developed.
Kinetics of domain growth and wetting in a model porous medium.

We report results from computer simulations of the kinetics of domain growth and wetting in a binary liquid mixture contained inside a model porous medium which has an interconnected and tortuous structure resembling Vycor glass. We find that the growth process slows down dramatically when the average size of the domains is comparable to the average pore radius and dynamical scaling breaks down at late stages. We argue that the random field model cannot be invoked to explain these results. On the other hand, the single-pore model seems to be reasonably successful in explaining the source of this slow growth.
Populistic Deliberation and Talk Radio

In modern mass societies much political deliberation is mediated by professional communicators, who may fail to represent the values of ordinary citizens. This analysis of the 1993 withdrawal of Zoe Baird as nominee for U. S. attorney general suggests, however, that when this occurs, direct popular intervention through alternative media sometimes reshapes political discourse and policy-making. Relying heavily on official sources (and perhaps misled by communicators' own class positions), most mainstream media supported Baird and predicted her confirmation, even after the revelation that she had hired illegal aliens and failed to pay their Social Security taxes. Only an outpouring of public outrage, expressed in calls to radio talk shows and senators' offices, and confirmed by national opinion surveys, turned the tide against the nominee. In this paper, we discuss the conditions under which such uprisings occur.
RESPONSES TO NUCCETELLI, LEMOS, AND BUENO

: Susana Nuccetelli discusses critically my account of Moore's Proof of the External World. Noah Lemos takes up my views on skepticism and my distinction between animal knowledge and reflective knowledge. Otavio Bueno focuses on my treatment of dream skepticism. In this article I offer replies to my three critics.
An exonuclease protection assay reveals heat-shock element and TATA box DNA-binding proteins in crude nuclear extracts

The ability to identify and purify trans-acting cellular factors that regulate eukaryotic genes is limited by the lack of a practical general assay. Current procedures using crude whole cell or nuclear extracts that restore transcriptional function in vitro or permit reconstruction of native chromatin at control sequences are effective only in select systems. I now present an exonuclease protection assay that is generally applicable for detecting sequence-specific DNA-binding proteins. The assay extends earlier work on the binding to the Drosophila heat-shock gene control element of a protein factor (HAP) present in crude nuclear extracts; the binding was shown by reconstitution of specific exonuclease resistance within a nuclease-hypersensitive site in chromatin1,2. We show here that this same exonuclease resistance can be reconstituted on free linear DNA, despite many nonspecific binding activities present in unfractionated nuclear extracts. We have further applied this assay method to fractionate the protein factor that is bound constitutively to the heat-shock gene TATA box region in native chromatin1. Exonuclease protection offers a sensitive, precise and rapid assay for any sequence-specific DNA-binding protein.
Photochemical redox cycling of iron in coastal seawater

Reduced iron, Fe(II), and hydrogen peroxide, H2O2, were measured in numerous laboratory solar simulation experiments. Under constant irradiation of freshly collected, 0.2 μm filtered water from Narragansett Bay (NBSW), H2O2 accumulates in a linear fashion for at least 2 h at rates from 30 to 59 nM h−1. Our measurements of Fe(II) accumulation in this study provide some of the first direct measurements of photochemical iron reduction in natural seawater at pH 8 in a controlled laboratory setting. At ambient pH, the peak concentration of Fe(II) ranged from 4 to 8% of the total iron concentration. Lowering the pH resulted in increased Fe(II) concentrations over the entire course of the experiment. Measured H2O2 accumulation, published iron oxide solubility products, and published reaction rates for iron oxidation and reduction by oxygen, hydrogen peroxide, and oxygen radicals were used to develop a kinetic model which accounts for the general magnitude and timing of Fe(II) concentration variations observed in our experiments. Our model shows that measured steady state Fe(II) concentrations in irradiated seawater are controlled largely by pH dependent oxidation by oxygen and hydrogen peroxide, and by both oxidation and reduction of iron by photochemically produced Superoxide.
Stationary Distributions in the Atom-on-Demand Problem

In this note a probability model for the number of atoms in a magneto-optical trap is suggested. We study an ergodic Markov chain for the number of atoms in the trap under a feedback regime for different load distributions. Formulas for the stationary distribution of the process are derived in several cases. They can be used to adjust the loading rate of atoms to maximize the probability of a single atom in the trap. Approximate optimal regimes are found.
Surgical management of mitral valve infective endocarditis

Active mitral valve infective endocarditis is a challenging clinical problem with a high rate of mortality. Surgery is currently performed in more than 40% of patients, and selecting those patients who will benefit from surgical intervention and performing a technically sound operation at the proper time are keys to optimizing outcomes. Moderate-to-severe and severe mitral regurgitation, large, mobile vegetations, paravalvular abscess, embolic events, failure of antibiotic therapy, and infection with a fungal organism are indications for prompt operation. The use of computed tomography imaging is important to determine whether there are noncardiac sources of infection, and transesophageal echocardiography is essential to delineate valvular dysfunction, identify paravalvular abscesses, rule out involvement of other valves, and plan operative therapy. In most cases, surgery should not be delayed because of cerebrovascular emboli. Mitral valve repair is favored over replacement whenever possible, is associated with superior short- and long-term outcomes, and should be possible in most cases. Operative mortality is 80%.
Protective values for soil lead with respect to child health: a critique of UK guidelines

In 2002, The (UK) Department for Environment, Food and Rural Affairs (DEFRA) together with the Environment Agency published document SGV10 “Contaminants in soil: collation of toxicological data and intake values for humans. Lead”. This publication sets out the derivation of Soil Guideline Values for lead contamination. Values for soil lead that are protective of the health of children and also for adults are derived using the model recommended by an international task force working under the auspices of the Society for Environmental Geochemistry and Health (SEGH) (Wixson and Davies 1993, 1994). Detailed examination of the DEFRA publication shows it uses unrealistic values for two variables in the SEGH model. The consequence is both actual and has potential adverse societal impacts. These impacts could be avoided if the appropriate scientific community were regarded as stakeholders in the legislative outcome and not simply the providers of the research data.
19. Shoucheng OuYang, where the legend begins

In this paper, a detailed historical account of the birth, development, and applications of the theory of blown‐ups is given.
Lineage-specific decay of folate biosynthesis genes suggests ongoing host adaptation in phytoplasmas.

Phytoplasmas are nonculturable cell wall-less, obligate intracellular pathogens of plants and insect vectors. In their descent from walled bacterial ancestors, phytoplasmas underwent massive genome...
A vibration isolation platform

This paper describes one of the projects for the undergraduate course 2.737 Mechatronics in the Mechanical Engineering Department at MIT. This project uses an 8-inch audio speaker as the basis for a one-axis vibration isolation platform. This system is intended to isolate the platform from base vibrations and also to stabilize the platform with respect to on-board generated disturbances. This function is similar to that required for isolating precision machines such as wafer steppers and coordinate measuring machines. This project provides a context for students to deepen their understanding of frequency-domain feedback design techniques and implementation issues.
Internet Power and Social Context: A Globalization Approach to Web Privacy Concerns

Contemporary perspectives on the Internet don't recognize negotiations about its meaning that take place in many societies, causing the Web to be defined simultaneously in terms of local cultures and world markets. We propose a "globalization" perspective that can help researchers situate a society's cultural and technological practices within broad political and economic parameters, identify global forces and local voices, and study dynamics of their co-existence. As an exploratory foray, we compare U.S. and Israeli parents' attitudes toward Web privacy. The findings call attention to a need for historical and geographical considerations at every level of Web research.
Effect of an adjacent cavity on the interaction of elastic waves with a crack

Abstract Scattering of time-harmonic elastic waves by a configuration of a macrocrack and an adjacent microcavity is investigated. The problem formulation is two-dimensional and for a state of plane strain. A traction boundary integral equation formulation is developed. Numerical calculations by the boundary element method have been carried out for several geometrical configurations. The dependence of scattered fields and elastodynamic stress intensity factors on angle of incidence of elastic waves, microcavity diameter and microcavity location has been discussed.
Behavioral aspects of trauma in children and youth

Trauma is prevalent in the lives of children. It derives from many sources, and, depending on its characteristics, can produce transient or enduring and devastating consequences. Early trauma, if left untreated, can set the stage for chronic deficits in the behavioral repertoires of affected children, and thus shape personality development. Additionally, when trauma is repetitive and chronic, the developing brain may be affected in ways that impede otherwise effective intervention. Yet diagnosing traumatic stress in children requires a departure from exclusively adult-like considerations and attention must be devoted to the ongoing developmental processes. Trauma-associated clinical features in children are sharply distinct from those that are associated with adult traumatization and must be taken into account from screening and diagnosis through treatment and outcome evaluation. We suggest that a learning foundation for symptom development will best assist the identification and selection of efficacious treatments. Pediatricians should make use of validated screening procedures that effectively identify affected children to facilitate timely referral and ongoing monitoring of treatment outcomes for their patients. A representative list of such instruments can be found in Table 1. With respect to hospital-based trauma work, we suggest the following recommendations: Professionals must be alert to the presence of acute stress symptoms in any child or parent after all injury incidents. These symptoms may occur in any injured child regardless of age, gender, injury severity, mechanism of injury, or length of time since injury. Certain mechanisms of injury, (ie, pedestrian versus motor vehicle collision), place the parent at higher risk for symptomatology. All family members, including parents and siblings, must be considered at risk for acute and long-term functional abnormalities. It is important to educate patients and family members that acute stress symptoms are common after an injury incident and are likely to resolve as the patient's injuries heal. Yet despite this, before discharge from the hospital, parents must be taught to evaluate their traumatized child's behavior, as well as their own, for any evidence of posttraumatic stress disorder. Health care providers must anticipate potential strain upon family relationships and financial resources. Parent's posttraumatic stress symptoms may result in deterioration of their own ability to support their injured child. And finally, reassessment of patient and family members should occur within the first days, at 1 to 2 weeks, 6 months, and 1 year following injury to ensure proper recovery and optimization of psychosocial function.
Characterization of Sindbis virus epitopes important for penetration in cell culture and pathogenesis in animals.

Abstract Two anti-glycoprotein E2 monoclonal (MC) antibodies, designated R6 and R13, prepared against an attenuated mutant (SB-RL) of Sindbis virus, preferentially neutralize attenuated, rapidly penetrating strains of Sindbis as opposed to virulent, more slowly penetrating strains. An antigenic variant of SB-RL which displayed reduced reactivity with R6 and R13, demonstrated virulence in suckling mice and slow penetration in baby hamster kidney cells. Anti-E2 MC antibodies to SB-RL and to an independently propagated wild-type Sindbis strain, SIN. were used to compare the topographical relationship of the R6 and R13 epitopes to other E2 antigenic sites. The R6 and R13 epitopes constituted a previously undescribed E2 site. E2-c. Antibody competition experiments using virions in solid phase and in suspension, as well as binding of MC antibody to antigenic variants, demonstrated that E2-c was a spatially distinct and independently mutable site at the surface of Sindbis virions. Of three E2 antigenic sites, E2-a and E2-c were conserved among the Sindbis strains examined, while E2-b was strain specific. Although attenuated strains were preferentially neutralized by E2-c specific MC antibodies, the critical mutation in these strains did not alter their ability to bind E2-c MC antibody. Rather, the mutation was responsible for (1) the altered biological effect of antibody binding at E2-c; (2) the in vitro rapid penetration phenotype; and (3) the in vivo phenotype of attenuation in suckling mice.
Experimental Test of General Relativity and the Physical Metric

The author will show that neither the Schwarzschild metric nor the metric introduced in 1916 by Schwarzschild describes the data produced by the time delay experiment by Shapiro et al. The author will describe the physical metric that will explain the time delay experiment data correctly as a solution to Einstein Equation of General Relativity. Other tests of General Relativity, the bending of light, the advancement of perihelia, gravitational red shift and gravitational lensing are satisfied by both the Schwarzschild metric and author’s physical metric.
Flow measurement using speckle in optical coherence tomography images

Doppler optical coherence tomography (DOCT) is a valuable tool for depth-resolved flow measurements in tissue. However, DOCT suffers from two disadvantages: it is insensitive to flow in the direction normal to the imaging beam, and it requires knowledge of the phase of the demodulated signal. We present an alternative method of extracting flow information, using speckle of conventional amplitude optical coherence tomography images. The two techniques can be shown to be essentially equivalent, with the distinction that speckle methods are sensitive to flow in all directions but do not provide information on the direction of flow. It is well known in other imaging modalities that moving scatterers cause a time-varying speckle pattern. Due to the pixel-by-pixel acquisition scheme of conventional OCT, time-varying speckle is manifested as a change of OCT image spatial speckle frequencies. We tested the ability of speckle to provide quantitative flow information using a flow phantom (a tube filled with Intralipid flowing at a constant volumetric flow rate). Initially, m-scans were taken at over the center of the tube. Images were averaged to reduce noise and the region corresponding to the center one-quarter of the tube lumen was selected. Sequential a-scans were concatenated, the Fourier transform performed, and a ratio of high to low spatial frequencies computed. We found that, over a range of velocities, this ratio bore a linear relation to flow velocity. For two-dimensional imaging, the program was modified to use a sliding window. Parabolic flow profile was visualized inside the tube. This study shows the feasibility of extracting quantitative flow data in all directions without phase information.