cssi/SciSciGPT-SciSciNet huggingface dataset:
Fracture and deformation in brittle solids: A perspective on the issue of scale

A perspective on the issue of scale in the fracture and deformation properties of ordinarily brittle covalent–ionic solids (ceramics) is presented. Characteristic scaling dimensions for nanomechanical properties of this class of solids are identified—specimen size or layer thickness, microstructural scale, and contact dimension. Transitions in mechanical damage processes occur as the characteristic dimensions diminish from the macroscale to the submicroscale. Such transitions generally preclude unconditional extrapolations of macroscopic-scale fracture and deformation laws into the nanomechanics region. Strength of brittle solids tends to increase while toughness tends to decrease as the scaling dimensions diminish. The nature of flaws that control strength in the submicroscale region also undergoes fundamental changes—even flaws without well-developed microcracks can be deleterious to strength.
Biomimetic Composite Structural T-joints

Abstract Biological structural fixed joints exhibit unique attributes, including highly optimized fiber paths which minimize stress concentrations. In addition, since the joints consist of continuous, uncut fiber architectures, the joints enable the organism to transport information and chemicals from one part of the body to the other. To the contrary, sections of man-made composite material structures are often joined using bolted or bonded joints, which involve low strength and high stress concentrations. These methods are also expensive to achieve. Additional functions such as fluid transport, electrical signal delivery, and thermal conductivity across the joints typically require parasitic tubes, wires, and attachment clips. By using the biomimetic methods, we seek to overcome the limitations which are present in the conventional methods. In the present work, biomimetic co-cured composite sandwich T-joints were constructed using unidirectional glass fiber, epoxy resin, and structural foam. The joints were fabricated using the wet lay-up vacuum bag resin infusion method. Foam sandwich T-joints with multiple continuous fiber architectures and sandwich foam thickness were prepared. The designs were tested in quasi-static bending using a mechanical load frame. The significant weight savings using the biomimetic approaches is discussed, as well as a comparison of failure modes versus architecture is described.
A Model for Professional Development to Promote Engineering Design as an Integrative Pedagogy within STEM Education

Engineering design activities can help educators to apply concepts and processes from within and across STEM domains. To facilitate these connections, there is a need for sustained, job-embedded, and collegial professional development that brings together teachers from across STEM domains to engage in design-based activities. These activities can help teachers better understand engineering design processes and can foster collaborations. This can lead to a culture shift within the school by which integration of STEM concepts and process becomes more seamless for both educators and their students. This paper describes a research-based model for professional development to promote engineering pedagogy to support learning of STEM concepts within and across domains.
A nonverbal phoneme deletion task administered in a dynamic assessment format.

Abstract Purpose The purpose of the project was to design a nonverbal dynamic assessment of phoneme deletion that may prove useful with individuals who demonstrate complex communication needs (CCN) and are unable to communicate using natural speech or who present with moderate–severe speech impairments. Method A nonverbal dynamic assessment of phoneme deletion with a systematic prompting and scoring system was developed and compared to the same measure administered using a traditional “static” format. Both versions were administered to 64 typically developing children ranging in age from 6 to 8;5. The dynamic phoneme deletion task was designed so that no verbal response was required. Children were asked to point to pictures representing each stimulus item. The same stimulus items were administered to children in a traditional static format, without the use of pictures. For example, in the dynamic assessment task, children were asked to point to 1 of 4 pictures (e.g., ice) to indicate their response when asked to delete “m” from “mice.” In the static format, children were asked to “say” the real word left over after deleting “m” from “mice.” Correlations between phoneme deletion tasks and word-level reading tasks were calculated. Results Internal reliability for the nonverbal dynamic phoneme deletion task was α = .88 for the total sample. Correlations between the dynamic and static formats were high (r = .84) as were correlations between the deletion tasks and the measure of word-level reading (dynamic; r = .54, static; r = .53). Conclusions These preliminary findings suggest that the nonverbal dynamic phoneme deletion task holds promise for use with children for whom speech output is compromised. Implications for use with children who use AAC or who have significant speech impairments and recommendations for future research are discussed. Learning outcomes: Readers will learn about a nonverbal dynamic assessment of phoneme deletion that may prove useful for measuring phoneme awareness for children who are unable to communicate using natural speech or who present with moderate–severe speech impairments. Readers will learn about the importance of accurate measurement of phoneme awareness for children with complex communication needs. Readers will also learn about how to develop and utilize reliable and valid measures of phoneme awareness for this population of children with communication impairments.
The Philosophical Leninism and Eastern ‘Western Marxism’ of Georg Lukács

AbstractThis essay centres on the English translation (2000) of Georg Lukacs’s Tailism and the Dialectic (written in either 1925 or 1926). Lukacs is generally heralded as a founding theoretician of a ‘Western Marxism’, in opposition to ‘Eastern’ Soviet Marxism, and his most impressive and most influential work, History and Class Consciousness (1923), is generally treated as having rehabilitated Marxist concern with questions of subjectivity. It might therefore come as a surprise when Lukacs in Tailism states that the purpose of History and Class Consciousness was to demonstrate ‘that the organisation and tactics of Bolshevism are the only possible consequence of Marxism’. In my view, however, this should already be abundantly clear from History and Class Consciousness. For Lukacs’s absorption with proletarian subjectivity was motivated by an obsession with what he saw as its immaturity. And he coined the category of ‘reification’ in order to explain his disappointed expectations, to explain, that is, why the proletariat did not make a ‘socialist’ revolution in the ‘objectively ripe’ situation of an ‘imperialist war’ created by ‘moribund capitalism’. In short, Lukacs did raise anew the question of the subjective, but only to then declare that workers, not even ‘the most revolutionary among them’, could never attain proper class consciousness, which he attributed instead to the ‘revolutionary party’ bearing the properly revolutionary theory. For this reason I agree with Slavoj Žižek’s characterisation of Lukacs as the ‘ultimate philosopher [my emphasis] of Leninism’ – although I do think that Lenin himself would have found, as he did in connection with one of Lukacs’s other works, Marxism ‘present only at a verbal level’. My concern is two-fold: with a critique of the methodological short-cuts that Lukacs made in his purely conceptual derivation of the concept of reification, and his purely conceptual attribution of it as the necessary form of working-class consciousness ‘in its immediacy’; and with the dangerous political consequences that Lukacs derived from his assessment of the reified character of working-class subjectivity, mainly a theoretical guarantee that the party with the proper revolutionary theory must always be right, or at least more right than anyone else.
Bifurcation analysis for a modified Jeffcott rotor with bearing clearances

A HB (Harmonic Balance)/AFT (Alternating Frequency/Time) technique is developed to obtain synchronous and subsynchronous whirling motions of a horizontal Jeffcott rotor with bearing clearances. The method utilizes an explicit Jacobian form for the iterative process which guarantees convergence at all parameter values. The method is shown to constitute a robust and accurate numerical scheme for the analysis of two dimensional nonlinear rotor problems. The stability analysis of the steady-state motions is obtained using perturbed equations about the periodic motions. The Floquet multipliers of the associated Monodromy matrix are determined using a new discrete HB/AFT method. Flip bifurcation boundaries were obtained which facilitated detection of possible rotor chaotic (irregular) motion as parameters of the system are changed. Quasi-periodic motion is also shown to occur as a result of a secondary Hopf bifurcation due to increase of the destabilizing cross-coupling stiffness coefficients in the rotor model.
Capacity Choice and Allocation: Strategic Behavior and Supply Chain Performance

We consider a simple supply chain in which a single supplier sells to several downstream retailers. The supplier has limited capacity, and retailers are privately informed of their optimal stocking levels. If retailer orders exceed available capacity, the supplier allocates capacity using a publicly known allocation mechanism, a mapping from retailer orders to capacity assignments. We show that a broad class of mechanisms are prone to manipulation: Retailers will order more than they need to gain a more favorable allocation. Another class of mechanisms induces the retailers to order exactly their needs, thereby revealing their private information. However, there does not exist a truth-inducing mechanism that maximizes total retailer profits. We also consider the supplier's capacity choice. We show that a manipulable mechanism may lead the supplier to choose a higher level of capacity than she would under a truth-inducing mechanism. Nevertheless, her choice will appear excessively restrictive relative to the prevailing distribution of orders. Furthermore, switching to a truth-inducing mechanism can lower profits for the supplier, the supply chain, and even her retailers. Hence, truth-telling is not a universally desirable goal.
Is ryanodine receptor a calcium or magnesium channel? Roles of K+ and Mg2+ during Ca2+ release.

Abstract The ryanodine receptor (RyR) is a poorly selective channel that mediates Ca2+ release from intracellular Ca2+ stores. How RyR's selectivity between the physiological cations K+, Mg2+, and Ca2+ affects single-channel Ca2+ current amplitude is examined using a recent model of RyR permeation. It is found that K+ provides the vast majority of the countercurrent (through RyR itself) that is needed to prevent the sarcoplasmic reticulum (SR) membrane potential from changing and stopping Ca2+ release. Moreover, intra-pore competition between Ca2+ and Mg2+ defines single RyR Ca2+ current amplitude. Since both [Mg2+] and [Ca2+]SR can change during pathophysiological conditions, the RyR unitary Ca2+ current amplitude during Ca2+ release may change significantly due to this Ca2+/Mg2+ competition. Compared to the classic action of Mg2+ on RyR open probability, these Ca2+ current amplitude changes have as large or larger effects on overall RyR Ca2+ mobilization. A new aspect of RyR divalent versus monovalent selectivity is also identified where this kind of selectivity decreases as divalent concentration increases.
Dynamics of the random anisotropy model in the large-N limit☆

Abstract We present a formulation for the dynamics of the random anisotropy spin glass in the large-N limit. We find the conventional spin glass phase to be unstable against gaussian fluctuations at O(1/N).
Nucleotide sequences at the boundaries between gene and insertion regions in the rDNA of Drosophila melanogaster

Abstract Ribosomal RNA genes interrupted by type 1 insertions of 1 kb and 0.5 kb have been sequenced through the insertion region and compared with an uninterrupted gene. The 0.5 kb insertion is flanked by a duplication of a 14 bp segment that is present once in the uninterrupted gene; the 1 kb insertion is flanked by a duplication of 11 of these 14 bp. Short insertions are identical in their entire length to downstream regions of long insertions. No internal repeats occur in the insertion. The presence of target site duplications suggests that type 1 insertions arose by the introduction of transposable elements into rDNA. Short sequence homologies between the upstream ends of the insertions and the 28S′ boundaries of the rRNA coding region suggest that short type 1 insertions may have arisen by recombination from longer insertions. We have sequenced both boundaries of two molecules containing type 2 insertions and the upstream boundary of a third; the points of interruption at the upstream boundary (28S′ site) differ from each other in steps of 2 bp. Between the boundary in the 0.5 kb type 1 insertion and the type 2 boundaries there are distances of 74, 76, and 78 bp. At the downstream boundary (28S′′ site) the two sequenced type 2 insertions are identical. The rRNA coding region of one molecule extends across the insertion without deletion or duplication, but a 2 bp deletion in the RNA coding region is present in the second molecule. Stretches of 13 or 22 adenine residues occur at the downstream (28S′′) end of the two type 2 insertions.
An Application of Thermal Analysis to Household Waste

Thermal analysis combined with composition analysis has been used in this work to identify evolved gas when burning household waste. Thermogravimetry (TG) coupled with Fourier transform infrared (FITR) spectroscopy and mass spectrometry (TG-FTIR-MS) offers structural identification of compounds evolved during thermal processes. Carbon, hydrogen, and nitrogen elemental analysis and XRD offers raw materials information. All these combined can help to evaluate the chemical pathway for the degradation reactions by determining the decomposition products. For comparison purposes, emitted species concentrations are measured with multiple-sensors when burning household waste in a lab-scale fluidized bed combustor. There is excellent agreement between the two different approaches. The measured results also provided some insight into burning household waste as an energy source in large-scale incinerators.
The quasi-stationary coronal magnetic field and electron density as determined from a Faraday rotation experiment

Quasi-stationary coronal magnetic field and electron density from Faraday rotation experiment, using theoretical model
The genetics of hormonal influences on male sexual behavior of mice and rats

This review focuses on the intersection of genes and hormones as they relate to the development of male sexual behavior. Three major hypotheses are discussed: (1) Some differences in adult male sexual behavior are due to gene differences that influence brain differentiation. Genes that influence brain differentiation may do so by affecting the elaboration of testosterone (i.e., H-Y antigen) or the sensitivity to testosterone (i.e., Tfm mutation and autosomal variations) during neonatal and/or prenatal life. (2) Some differences in male sexual behavior are due to gene differences that influence adult levels of testosterone or sensitivity to testosterone and its metabolites. (3) There is a gene(s) on the Y chromosome that influences the development of sexual behavior that is associated with the arousal mechanism. A possible hormonal mechanism of this Y chromosomal gene(s) is discussed.
Colors of reflection nebulae. I - Phase function effects in the Merope nebula

The subject of color differences between reflection nebulae and their illuminating stars is reexamined in the light of developments of observational techniques, permitting accurate surface-brightness photometry over an expanded spectral region from the UV to the IR. Color-color diagrams for reflection nebulae can yield useful information about the wavelength dependence of the scattering properties of nebular dust without excessive sensitivity to the specific nebular geometry or the presence of multiple scattering, resulting in considerable savings in computational efforts. As an illustration, the color-difference method was applied to existing data for the Merope nebula, covering the spectral region 1550-5500 A. Strong evidence for a monotonically changing phase function of scattering at wavelengths less than or equal to 3500 A is found. The result is interpreted in the context of a plausible geometry for the Merope environment as providing support for a bimodal size distribution of nebular dust grains.
Effects of urinary pH on the behavioral responses of squirrel monkeys to nicotine

Abstract The present study evaluated the behavioral effects of nicotine under conditions that manipulated urinary pH. The effects of nicotine were examined on the responding of squirrel monkeys under a multiple fixed-interval, fixed-ratio schedule of stimulus-shock termination when nicotine was administered alone or together with the gastric administration of an acidifier (ammonium chloride) or an alkalanizer (sodium bicarbonate). Responding under the FI schedule was increased markedly across a range of doses of nicotine (0.02–0.20 mg/kg). Responding under the FR was increased to a lesser by the lower doses of nicotine (0.02–0.05 mg/kg) and was decreased by doses of nicotine that increased responding under the FI (0.10-0.20 mg/kg). Generally, administration of the acidifier attenuated the effects of nicotine while administration of the alkalinizer potentiated those effects. These findings support the argument that changes in cigarette smoking under conditions that alter urinary pH involve nicotine per se. In addition, a new interpretation of the relationship between urinary pH and cigarette smoking is offered.
Global strichartz estimates for nonthapping perturbations of the laplacian

(2000). Global strichartz estimates for nonthapping perturbations of the laplacian. Communications in Partial Differential Equations: Vol. 25, No. 11-12, pp. 2171-2183.
Real-time monitoring and detecting of after-burning hazards of continuous catalyst regenerators

Abstract Chemical process operations are rarely steady and often vary with time. Slow and persistent process drifts associated with gross errors make data rectification difficult. In this study, a multivariate statistical process control method for detecting abnormal process conditions, which is based on the posterior mode estimator, was proposed. It first decomposed the observation equation of a state–space model into a trend component, an irregular component, and a gross error component with recursive transition equations. A penalized least-square method was then applied to derive the maximized likelihood and unbiased estimation of the measurements. A precise prior-assigned model was not needed for the estimator, and it could be implemented on-line easily. Statistical methods based on Hotelling's T 2 distance, Wilks Λ criterion, simultaneous confidence intervals, and measurement tests were adopted to detect abnormal drifts in process operations. For performing these tests, a simple method of introducing a forgetting estimation on the steady-state operation values was suggested to enhance the robustness property and to treat the effects of non-steady data measurements. An on-line monitoring system, underlying the desire for real-time analysis and monitoring in chemical or petrochemical plants, was developed for detecting process upsets and drifts. The promising performance of the proposed method in detecting after-burning hazards has finally been demonstrated by a continuous catalyst regenerator in comparison with the results suggested by a senior process engineer for practical operations.
Simulation Analysis of Platelet Production and Inventory Management

To maximize the availability of platelet concentrates (PC) and minimize their outdate, competing criteria, a computer simulation model of platelet production and distribution was developed. Based on 2 years of actual platelet orders placed with a regional blood center, the simulation program generated daily platelet orders, and also calculated mean demand and standard deviation of demand for each day of the week. The number of PC to be produced on a given day was calculated from: PC to be produced = (mean demand for that day of the week) + Tx (standard deviation of demand for that day of the week)-(PC in inventory on the given day), where T is a selected multiple of the standard deviation. As T increases, availability is maximized, but outdating is expected to increase. Conversely, lower T is associated with less availability, but lower outdate. At the simulated platelet demand level (about 735 PC per week), with 3-day platelet storage life, 99% availability is associated with 1% outdate and distribution of PC of less than 1 day average age. 100% availability, with no outdate is predicted for a 5-day storage life, with no further improvement in logistics with 7-day storage life, at this level of demand. Although logistics of platelet production and distribution vary from center to center, the simulation analysis is generally applicable, and a formal plan has the great advantage of predictive, rather than reactive, platelet production.
Optimizing recording capabilities of the Utah Intracortical Electrode Array.

Abstract The Utah Intracortical Electrode Array is a unique silicon-based monolithic structure designed for use as a multichannel interface to the central nervous system. In this paper, we describe a series of acute experiments designed to determine the neural recording capabilities of this electrode array and the dependence of the signal-to-noise ratio (SNR) of the recordings on the electrode surface area (length of metallized tip). We found that both separable unit and multiunit cluster responses could be recorded. Additionally, high SNR recordings could be achieved for some electrodes (with electrode tip lengths of 30–220 μm), while recordings with signals substantially greater than the noise could be made from most of the electrode provided that the proper electrode surface area was used. The demonstrated recording capabilities of the Utah Intracortical Electrode Array and its unique three-dimensional structure should form the basis for innovative physiological investigations into the functional organization of the cortex as well as for long term neuroprosthesis development.
Photoinduced Carrier Generation and Recombination Dynamics of a Trilayer Cascade Heterojunction Composed of Poly(3-hexylthiophene), Titanyl Phthalocyanine, and C60.

We use flash-photolysis time-resolved microwave conductivity experiments (FP-TRMC) and femtosecond–nanosecond pump–probe transient absorption spectroscopy to investigate photoinduced carrier generation and recombination dynamics of a trilayer cascade heterojunction composed of poly(3-hexylthiophene) (P3HT), titanyl phthalocyanine (TiOPc), and fullerene (C60). Carrier generation following selective photoexcitation of TiOPc is independently observed at both the P3HT/TiOPc and TiOPc/C60 interfaces. The transient absorption results indicate that following initial charge generation processes to produce P3HT•+/TiOPc•– and TiOPc•+/C60•– at each interface from (P3HT/TiOPc*/C60), the final charge-separated product of (P3HT•+/TiOPc/C60•–) is responsible for the long-lived photoconductance signals in FP-TRMC. At the P3HT/TiOPc interface in both P3HT/TiOPc and P3HT/TiOPc/C60 samples, the electron transfer appears to occur only with the crystalline (weakly coupled H-aggregate) phase of the P3HT.
Dietary 1,25-dihydroxycholecalciferol has variable effects on the incidences of leg abnormalities, plasma vitamin D metabolites, and vitamin D receptors in chickens divergently selected for tibial dyschondroplasia

Abstract Three experiments were conducted to examine the efficacy of dietary 1,25-dihydroxycholecalciferol [(1,25-(OH)2D3)] on the development of tibial dyschondroplasia (TD) in chickens divergently selected for high (HTD) and low (LTD) incidences of TD. In Experiment 1, chickens from the two lines were fed two calcium levels (0.75 and 1.0%), with and without 5 micrograms/ kg dietary 1,25-(OH)2D3. In Experiment 2, both lines were fed diets containing 1.0% calcium and 0, 5, 10, or 15 micrograms/kg 1,25-(OH)2D3. The addition of 1,25-(OH)2D3 did not reduce the overall incidence of TD in Experiment 1, but did reduce the incidence of severe TD from 69 to 48% in the chickens receiving the 0.75% calcium diet. In this experiment, LTD chickens had higher plasma phosphorus and bone ash. No line differences were noted between plasma vitamin D metabolites or intestinal vitamin D receptors. In Experiment 2, 5 micrograms/kg of 1,25-(OH)2D3 decreased the incidence of TD from 94 to 76% and number three scores from 69 to 44% (P
Conformational Dynamics in Human Purine Nucleoside Phosphorylase with Reactants and Transition-State Analogues†

Dynamic motions of human purine nucleoside phosphorylase (hPNP) in complex with transition-state analogues and reactants were studied using 10 ns explicit solvent molecular dynamics simulations. hPNP is a homotrimer that catalyzes the phosphorolysis of purine 6-oxynucleosides. The ternary complex of hPNP includes the binding of a ligand and phosphate to the active site. Molecular dynamics simulations were performed on the ternary complex of six ligands including the picomolar transition-state analogues, Immucillin-H (Kd = 56 pM), DADMe-Immucillin-H (Kd = 8.5 pM), DATMe-Immucillin-H (Kd = 8.6 pM), SerMe-Immucillin-H (Kd = 5.2 pM), the substrate inosine, and a complex containing only phosphate. Protein−inhibitor complexes of the late transition-state inhibitors, DADMe-Imm-H and DATMe-Imm-H, are inflexible. Despite the structural similarity of SerMe-Imm-H and DATMe-Imm-H, the protein complex of SerMe-Imm-H is flexible, and the inhibitor is highly mobile within the active sites. All inhibitors exhibit an incr...
Seeing culture and power in mathematical learning: toward a model of equitable instruction

This paper is centered on creating equitable opportunities for learners in mathematics education. Through observations of teacher practice, the paper seeks to theorize how teachers enact their dispositions toward mathematics instruction. These observed propensities, in relation to teachers’ aims for students to “take up their space” in and beyond the mathematics classroom, then inform a model of equitable mathematics instruction. Teachers’ dispositions are considered in relation to Mason’s discipline of noticing and Bourdieu’s notion of the symbolic violence of dominant discourses.
“Friends in Deed” for librarians in need

Purpose – The purpose of this paper is to describe a library‐based hardship fund for librarians in personal financial crisis.Design/methodology/approach – Discusses the proposal for library‐based financial support to sustain librarians' memberships to professional organizations and travel expenses for one year.Findings – Libraries supporting professional development should assist librarians achieve this goal in times of personal financial hardship when a crisis may prevent the librarian from carrying on with his/her normal commitments.Originality/value – Although similar plans exist at the university level, none exist at the immediate, personal level of the library.
Improvement of therapeutic index for brain tumors with daily image guidance

Background: Image-guidance maximizes the therapeutic index of brain irradiation by decreasing setup uncertainty. As dose-volume data emerge defining the tolerance of critical normal structures responsible for neuroendocrine function and neurocognition, minimizing clinical target volume (CTV) to planning target volume (PTV) expansion of targets near these structures potentially lessens long-term toxicity. Methods: We reviewed the treatment records of 29 patients with brain tumors, with a total of 517 fractions analyzed. The CTV was uniformly expanded by 3 mm to create the PTV for all cases. We determined the effect of patient specific factors (prescribed medications, weight gain, tumor location) and image-guidance technique on setup uncertainty and plotted the mean +/� standard deviation for each factor. ANOVA was used to determine significance between these factors on setup uncertainty. We determined the impact of applying the initial three fraction variation as custom PTV-expansion on dose to normal structures. Results: The initial 3 mm margin encompassed 88% of all measured shifts from daily imaging for all fractions. There was no difference (p = n.s.) in average setup uncertainty between CBCT or kV imaging for all patients. Vertical, lateral, longitudinal, and 3D shifts were similar (p = n.s.) between days 1, 2, and 3 imaging and later fractions. Patients prescribed sedatives experienced increased setup uncertainty (p < 0.05), while weight gain, corticosteroid administration, and anti-seizure medication did not associate with increased setup uncertainty. Patients with targets near OAR with individualized margins led to decreased OAR dose. No reductions to targets occurred with individualized PTVs. Conclusions: Daily imaging allows application of individualized CTV expansion to reduce dose to OAR responsible for neurocognition, learning, and neuroendocrine function below doses shown to correlate with long-term morbidity. The demonstrated reduction in dose to OAR in this study has implications for quality of life and provides the motivation to pursue custom PTV expansion.
Oral Burkitt's lymphoma in children: the Moroccan experience

Thirty-seven children with Burkitt's lymphoma of the oral region diagnosed between 1998 and 2005 were reviewed. There were 31 boys and 6 girls. The mean age at diagnosis was 6.64 years (range 2-15 years) with a mean delay to diagnosis of 41 days (range 10 days-2 months). There was a predominance of maxillary over mandibular involvement: 1.44:1. Complaints included exophytic mass with dental displacement (100%), abdominal pain (68%), nerve palsy (28%) and orbital swelling (21%). Toothache as initial complaint led to dental extraction in 12 cases. According to the Murphy classification, there were 4 stage II, 11 stage III and 22 stage IV tumours; 43% and 41% had bone marrow and central nervous system involvement, respectively. After chemotherapy, complete remission was seen in 59% of cases. Remission in two children was relatively brief, lasting no more than 3 months. After a median follow-up of 45 months (range 9-99 months), the disease-free survival rate was 54%. In conclusion, in this series, oral presentation of Burkitt's lymphoma was a component of more widely disseminated disease. The pattern seemed to fall between that of the endemic and the sporadic types. Even with intensive chemotherapy, patients with advanced disease maintained a poor prognosis.
Temperature-mediated regulation and downstream inducible selection for controlling gene expression from the bacteriophage λ pL promoter

We have examined in detail the effects of various induction temperatures on the expression of a heterologous fusion gene controlled by the bacteriophage lambda PL promoter in a heat-inducible Escherichia coli expression system which utilizes the CIts857 repressor. Experiments performed over a temperature range spanning 29-42 degrees C indicate that, under our conditions, temperatures as low as 29 degrees C may be required to fully repress the CI857-controlled transcription from PL, and that the highest protein yields are obtained after induction at 36 degrees C for 6 h. We cloned the cat reporter gene downstream from a heterologous gene controlled by PL and found that cat expression at a low induction temperature permits the monitoring of productive transcription through the heterologous gene and thus aids in selecting transformants that are capable of producing the heterologous protein in E. coli.
The effect of diet on multiple site regulation of glycolysis in rat skeletal muscle. 2. Activation of PFK-1 and control of F2 6BP synthesis by PFK-2/F-2,6-BPase

Abstract The involvement of PFK-1, F2,6BP and PFK-2/F2,6BPase in dietary fat induced alterations in insulin responsiveness of skeletal muscle was examined in rats were fed either a high fat (HF) (67%kcal) or high carbohydrate (HC) (67%kcal) diet for 21 days, ad libitum. Insulin increased the total activity of PFK-1 in EDL and soleus muscle from both HC and HF fed rats. However, the insulin-stimulated increase in PFK-1 activity in muscle obtained from HF-fed rats was significantly less than from HC-fed rats; supporting previous studies examining invitro glucose metabolism. However, data examining the role of F2,6BP in the control of glycolysis were not consistent with previous reports in liver. Insulin addition produced a significant increase in [F2,6BP] in both muscle types in HF-fed rats but not in the HC-fed rats suggesting an alteration(s) in the control of the synthesis of F2,6BP. Assay of PFK-2/F2,6BPase showed that total PFK-2 increased with the addition of insulin independent of muscle type or dietary treatment. However, only EDL active PFK-2 from the HF treatment was responsive to insulin addition. The addition of insulin resulted in an increase in both the total and active form of F2,6BPase in soleus and EDL muscles from the HC treatment group. In contrast, The active form of soleus F2,6BPase decreased significantly (50%) upon incubation with insulin in HF-fed rats, while the EDL F2,6BPase decreased 25% in HF-fed rats. These data suggest that (1) F2,6BP may not play a major role in the regulation of glycolysis in skeletal muscle and (2) increase dietary fat may alter the manner of regulation of F2,6BP synthesis/degradation.
NUMERICAL ESTIMATES OF ANCIENT WAVES, WATER DEPTH AND FETCH

A series of carefully controlled marine experiments, in which sand of known grain diameter and essentially perfect sorting was exposed to waves of various sizes, was supplemented by study of lakes of various widths (and hence differing values for fetch), in an effort to obtain relationships between parameters measurable in sedimentary rocks (i.e., ripple-mark spacing) and paleogeo-graphic information (water depth, wave height, wave length, and fetch). The results were subjected to regression analysis. Two equations were obtained, relating ripple-mark spacing to grain size, water wavelength and water depth, with predictive abilities higher than 80%. Two equations were obtained, relating ripple-mark spacing to grain size, water wave-height and water depth, with a predictive ability of 75%-80%. Two useful equations involved water wave-length, and two involved water wave-height; in general those based on water wave-length were superior to those based on water wave-height. In shallow-water work, the pairs of values which can be obtained from equations included in this paper are highly limited in range, and thus define the paleogeographic unknowns reasonably closely. These pairs (or single values, as may be appropriate) can be inserted into three additional equations, which relate fetch to various wave parameters. An application is made to Jurassic rocks (lower Morrison sandstones) in northern New Mexico, which are interpreted as deposits of a large, shallow lake. Shorelines, where they cannot be located by inspection of the rocks, can be inferred fairly closely from the fetch data.
Fluctuating annihilation cross sections and the generation of density perturbations

Fluctuations in the mass and decay rate of a heavy particle which for some period dominates the energy density of the Universe are known to lead to adiabatic density perturbations. We show that generically the annihilation cross section of the same particle also receives fluctuations, which leads to entropy perturbations at freeze-out. If the particle comes to dominate the energy density of the Universe and subsequently decays, this leads to an additional source of adiabatic density perturbations. On the other hand, nonadiabatic density perturbations result when the particle does not decay but contributes to the observed dark matter.
Competition and Cooperation Among Working Women in the Context of Structural Adjustment: The Case of Street Vendors in la Paz-El Alto, Bolivia

This case study of women street vendors in La Paz-El Alto, Bolivia, examines the dynamics of competition and cooperation among this group of poor working women in the context of economic structural adjustment and political pluralization. It is argued that the economic and political reforms not only increase street vendors’insecurities, but may also undermine the potential for their broad-based solidarity and collective actions. Extreme competition in the overcrowded street commerce, diminishing returns, and disillusionment with traditional forms of workers’ organization hinder cooperation among street vendors and fragment the social body of the street marketplace, often by further reinforcing its gender, class, ethnoracial, and religious fault lines.
Cytogenetic findings in a pleomorphic xanthoastrocytoma.

Abstract We report a pleomorphic xanthoastrocytoma with an abnormal clonal cell line of 48,XY,+3,+5,−20,−22,+der(7)t(7;?)(p22;?),+der(20)t(15;20)(q11;q13).
Residual effects of soil profile modification on water infiltration, bulk density, and wheat yield

Fine-textured soils of the Southern High Plains, of which Pullman (fine, mixed, thermic Torrertic Paleustolls) is the dominant series, have inherently low water infiltration rates. Pullman soils have a moderately permeable surface horizon overlying and slowly-permeable Bt horizon, which limits deep water penetration, thus hampering water conservation efforts and reducing water-use efficiencies for crop production. In 1964, Pullman clay loam was profile-modified (PM) to 0.9- and 1.5-m depths. The objective of the 1990-1991 study was to compare soil bulk density (D b ), water infiltration, plant available water (PAW) content, and winter wheat (Triticum aestivum L.) yield on PM and unmodified soil [...]
Modeling wind-driven circulation during the March 1998 sediment resuspension event in Lake Michigan

[1] A three-dimensional primitive equation numerical ocean model was applied to Lake Michigan to simulate hydrodynamic conditions during the March 1998 sediment resuspension event in southern Lake Michigan caused by a storm with winds up to 20 m/s. The hydrodynamic model is driven with surface winds derived from observed meteorological conditions at 18 land stations and a meteorological buoy and also with surface winds calculated using a mesoscale meteorological model. Current observations from 11 subsurface moorings showed that the model driven with observed winds was able to qualitatively simulate wind-driven currents but underestimated current speeds during the most significant wind event. In addition, a pronounced offshore flow in the area of observations was also underestimated. Hydrodynamic model results using the meteorological model winds as the forcing function showed significant improvement over model results which were based on observed winds proving the importance of mesoscale winds for current modeling in large lakes.
In vitro actin filament sliding velocities produced by mixtures of different types of myosin

Using in vitro motility assays, we examined the sliding velocity of actin filaments generated by pairwise mixings of six different types of actively cycling myosins. In isolation, the six myosins translocated actin filaments at differing velocities. We found that only small proportions of a more slowly translating myosin type could significantly inhibit the sliding velocity generated by a myosin type that translocated filaments rapidly. In other experiments, the addition of noncycling, unphosphorylated smooth and nonmuscle myosin to actively translating myosin also inhibited the rapid sliding velocity, but to a significantly reduced extent. The data were analyzed in terms of a model derived from the original working cross-bridge model of A.F. Huxley. We found that the inhibition of rapidly translating myosins by slowly cycling was primarily dependent upon only a single parameter, the cross-bridge detachment rate at the end of the working powerstroke. In contrast, the inhibition induced by the presence of noncycling, unphosphorylated myosins required a change in another parameter, the transition rate from the weakly attached actomyosin state to the strongly attached state at the beginning of the cross-bridge power stroke.
Generation of polymer ultrafine fibers through solution (air-) blowing

Solution (air-) blowing, an innovative technique for generation of ultrafine polymer fibers from solutions, was developed by feeding polymer solutions (instead of melts) to a die assembly similar to that used in the conventional melt (air-) blowing process. Micro- to nano-scaled polyvinylpyrrolidone (PVP) fibers were produced using PVP solutions with water, ethanol, and/or their mixtures as the solvents; and the morphologies of the fibers were examined by scanning electron microscopy. The processing variables, including PVP concentration, air-blowing pressure, solution-feeding pressure, and the volatility of the solvent system (the ratio of ethanol to water), were systematically investigated. The results indicated that solution (air-) blowing was a viable technique to produce nonwoven fabrics consisting of ultrafine polymer fibers with diameters ranging from micrometers to nanometers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Implementation Challenges for a Constructivist Physical Education Curriculum.

Background: Curriculum fidelity describes the extent to which a curriculum is implemented faithfully as planned. Curriculum fidelity issues may arise when teachers implement the curriculum inconsistently due to differences in philosophy, barriers in the setting, or other local concerns. Purpose: The study examined challenges that a teacher faced in implementing a constructivist physical education curriculum that had fidelity implications. Research design: Ethnographic case study design was employed in the research. Participants and setting: One physical education teacher, ‘Daniel’, and his students in the third, fourth, and fifth grades participated in the study as they were involved in a curriculum intervention in a large urban school district in the US. Daniel's school was randomly assigned to an experimental group to implement a physical education curriculum based on health/fitness-related science. Data collection: The researchers observed 75 lessons taught by Daniel using non-participant observation t...
Hypermediated Art Criticism

Technological media catapults our perception into what Marshall McLu han called "new transforming vision and awareness/'1 As our lives become more and more immersed in such technologies as television, film, and in teractive computers, we find ourselves inundated with a heightened sense of mindfulness?an aesthetic experience made possible through such com puter technological characteristics as hyperlinks, hypermedia, and hyper reality. In these terms, the prefix "hyper" represents various linking devic es inherent to computer technology that allure and transport us between, above, below, and toward vast areas of information, places, and peoples. Hypermediacy, according to Bob Cotton and Richard Oliver, is "an entirely new kind of media experience born from the marriage of TV and computer technologies. Its raw ingredients can be brought together in any combina tion. It is a medium that offers random access; it has no physical beginning, middle, or end." In other words, there is no set or static structure inherent in technological media. It is not so much an "anything goes" apparatus as it is an "anything is possible" system. The seemingly vast possibilities inher ent to technological media offer us many and alternate views of the world. Just as technological media encourage multiple means of viewing the world, no single approach to art criticism can be considered dominant, as several methods, methodologies, and approaches exist for responding to
Role of Endothelium-Derived Nitric Oxide in the Modulation of Canine Myocardial Mitochondrial Respiration In Vitro Implications for the Development of Heart Failure

The mechanism responsible for the regulation of cardiac function by endogenous nitric oxide (NO) remains unclear. In this investigation, O2 consumption by freshly isolated myocardial muscle segments from the left ventricular free wall of canine hearts was quantified by a Clark-type O2 electrode at 37 degrees C. S-nitroso-N-acetylpenicillamine (SNAP, 9 +/- 3% to 50 +/- 8%), bradykinin (BK, 14 +/- 3% to 30 +/- 5%), or carbachol (CCh, 15 +/- 4% to 29 +/- 4%) significantly attenuated tissue O2 consumption at doses of 10(-7) to 10(-4) mol/L (mean +/- SE, P < .05). The effects of BK and CCh, but not SNAP, were blocked by 10(-4) mol/L NG-nitro-L-arginine, consistent with both BK and CCh stimulating NO biosynthesis and with SNAP decomposing to release NO, respectively. Similar doses of 8-Br-cGMP caused a respiratory inhibition, but to a lesser extent (9 +/- 2% to 14 +/- 6%). A mitochondrial uncoupler, 2,4-dinitrophenol (at 1 mmol/L), blocked the effects of 8-Br-cGMP, but not those of SNAP, BK, or CCh, suggesting that the major site of action of NO is on mitochondrial electron transport. Myocardial muscle from dogs with pacing-induced heart failure had a basal O2 consumption rate of 251 +/- 21 nmol.min-1.g-1, which was 54% higher than the rate seen in muscle from normal healthy canine hearts. The inhibitory effects of BK and CCh on O2 consumption were not observed in failing cardiac tissue, but SNAP showed an unaltered inhibitory effect. Therefore, our results indicate that NO released from microvascular endothelium by BK, stimulation of muscarinic receptors, and perhaps flow velocity may play an important physiological role in the control of cardiac mitochondrial respiration, and the loss of this regulatory function may contribute to the development of heart failure.
Temporal dispersal: ecological and evolutionary aspects of zooplankton egg banks and the role of sediment mixing.

SYNOPSIS. Zooplankton egg banks are the accumulation of diapausing embryos of planktonic animals buried in the sediments of many aquatic ecosystems. These eggs, which are analogous life history stages to the seeds of many plants, can survive in a ready-to-hatch state for periods ranging from a few years to greater than a century. Their presence in ponds, lakes and near-shore marine environments has substantial implications for understanding trajectories of ecological and evolutionary change. When the sediments of lakes are structured in historical sequence, diapausing eggs extracted from different sediment ages can provide a means of studying past changes in community or population-genetic structure. A completely different aspect of egg banks derives from the fact that hatching of diapausing eggs can influence, through what can be thought of as temporal dispersal, population and community response to environmental change. Eggs hatching from diapause introduce to current environments species or genotypes laid at times in the distant past. In addition, egg banks create extended generation overlap that can play an important role in maintaining diversity in a fluctuating environment when different types (species or genotypes) are favored at different times. These distinct aspects of egg banks (i.e., their direct impact on ecological and evolutionary processes versus their usefulness in reconstructing historical changes), are potentially in conflict because for old eggs to hatch, the sediments must be at least partially mixed. This same mixing, however, degrades the accuracy of the historical record. Both aspects are possible, however, even within a single lake when sediment-mixing intensity is spatially heterogeneous.