cssi/SciSciGPT-SciSciNet huggingface dataset:
Enteroaggregative Escherichia coli: surface protein dispersin increases bacterial uptake of ciprofloxacin

Abstract Enteroaggregative Escherichia coli (EAEC) causes diarrhoea. The antibiotic of choice for treating EAEC infections is ciprofloxacin. EAEC differs from other subgroups of pathogenic E. coli by having a surface protein, dispersin, which has previously been shown to play an important role in ciprofloxacin susceptibility for EAEC model strain 042. To investigate further the role of dispersin in ciprofloxacin susceptibility, minimum inhibitory concentrations (MICs) were determined for 25 clinical isolates, including 15 with dispersin and 10 without. Dispersin-positive strains had a lower MIC than dispersin-negative strains. The mechanism of action behind this observation may be caused by dispersin (i) increasing the bacteria–antibiotic interaction or (ii) facilitating ciprofloxacin access to the intracellular target, DNA gyrase/topoisomerase. To test the role of dispersin in ciprofloxacin sensitivity, EAEC 042 as well as its isogenic mutants, dispersin mutant (042 aap ) and a mutant in the transporter apparatus gene aatA , believed to be involved in dispersin transport to the bacterial surface (042 aatA ), were utilised. As predicted, 042 had a higher sensitivity to ciprofloxacin than 042 aap , but it was also found that the MIC of 042 aatA was similar to 042 aap . To address the question of the role of dispersin in ciprofloxacin susceptibility, the concentration of ciprofloxacin bound in biofilms of 042 and 042 aap was quantified by treating bacteria with radiolabelled 2- 14 C-ciprofloxacin. The results showed that dispersin did not increase the amount of bound ciprofloxacin as a function of biomass, indicating instead that dispersin facilitates ciprofloxacin access to the intracellular target leading to increased antibiotic susceptibility.
Yukawa deflected gauge mediation in four dimensions

We construct a four dimensional realization of a higher dimensional model, Yukawa deflected gauge mediation, in which supersymmetry breaking is communicated to the visible sector through both gauge and Yukawa interactions. The reduction to four dimensions is achieved by ``deconstructing'' or ``latticizing'' the extra dimension. Three sites (gauge groups) are sufficient to reproduce the spectrum of the higher dimensional model. The characteristic features of Yukawa deflected gauge mediation, in particular, alignment of squarks and quarks, and a natural solution to the mu problem, carry over to the deconstructed version of the model. We comment on the implications of our results for a solution of the mu problem in the context of deconstructed gaugino mediation.
Generalized guinan-steinberg formula for the shear modulus at all pressures

The Guinan-Steinberg (GS) formula for the shear modulus at all pressures is widely used in material strength studies. As we demonstrate here, the GS formula predicts a value for the shear modulus that is higher than its actual value at low to moderate compressions, even if it has the correct ultrahigh-pressure limit. We show that the reason for this shortcoming is insufficient negative curvature in the GS shear modulus as a function of pressure and propose a generalized GS formula that is accurate at all pressures.
Parametric stabilization is easy

A polynomially parametrized family of continuous-time controllable linear systems is always stabilizabte by polynomially parametrized feedback.
A Model Theory of Modal Reasoning

This paper presents a new theory of modal reasoning, i.e. reasoning about what may or may not be the case, and what must or must not be the case. It postulates that individuals construct models of the premises in which they make explicit only what is true. A conclusion is possible if it holds in at least one model, whereas it is necessary if it holds in all the models. The theory makes three predictions, which are corroborated experimentally. First, conclusions correspond to the true, but not the false, components of possibilities. Second, there is a key interaction: it is easier to infer that a situation is possible as opposed to impossible, whereas it is easier to infer that a situation is not necessary as opposed to necessary. Third, individuals make systematic errors of omission and of commission. We contrast the theory with theories based on formal rules.
Clinical manifestations of jellyfish envenomation

Jellyfish produce clinical diseases in humans. Death from venom toxicity is more common than anaphylaxis. The main venom actions are on the cardiovascular, respiratory and renal systems and these agents may induce systemic symptoms accompanying their cutaneous lesions. Keloids, fat atrophy, gangrene, contractions, arthralgias, neuritis, hyperpigmentation, corneal ulcerations, vasospasm and post-envenomation herpes simplex or granuloma annulare may appear. Recurrent eruptions, distant-site eruptions, persistent lesions or urticaria can occur. Anaphylaxis is managed as usual and verapamil can counteract the cardiotoxin. Systemic analgesics outperform topical agents against the immediate painful sting which results from immediate intradermal stimuli. Few measures preventing nematocyst rupture from adherent tentacles are significantly effective clinically so tentacle removal should be delayed until the patient is stable.
Stimulation by anoxia of active chloride transfer in isolated bullfrog small intestine

Abstract 1. 1. In isolated bullfrog small intestine mounted between identical isotonic Na2SO4 Ringer solutions at pH 7.2, potential difference (PD) and short circuit current ( I sc ) are largely inhibited by N2 and by 2,4-dinitrophenol. The residual PD and I se sometimes found in the presence of N2 is abolished by mucosal fluoride. Following moderately short exposures, the inhibitory effects of N2 are completely reversed by O2. Following prolonged exposure to N2, PD and I sc are only partially restored by O2. 2. 2. When the tissue is mounted between identical Ringer solutions in which Na+ is completely replaced by Tris ions, PD (serosal negative) and I sc are markedly increased under anoxic conditions. In the presence of metabolized sugar (glucose or fructose) these increases are sustained and are reversed by O2. Glucose is effective whether it is present initially in the mucosal medium, the serosal medium, or both. The increase in PD and I sc observed with mucosal glucose is not inhibited by phlorizin. In substrate-free media or in media containing non-metabolized or poorly metabolized solutes ( 3-O- methylglucose , sorbose or valine) N2 elicits a transient increase only in PD and I se . In the presence of glucose, 2,4-dinitrophenol (mucosal or serosal) elicits increases in PD and I se similar to those induced by N2. In media containing glucose, N2 markedly increases m → s Cl− flux but does not change s → m Cl− flux. The increased m → s Cl− flux under these conditions is significantly greater than the corresponding increase in I se . Part of the discrepancy between these parameters can be attributed to a net co-transport of K+ from the mucosal to the serosal medium.
A Long Base Line Precision Tiltmeter

Abstract A two-fluid tiltmeter which eliminates the thermally induced errors that have long plagued water-tube tiltmeters has been constructed. While the small tiltmeters currently used tend to be limited because of their great sensitivity to contamination by local nontectonic tilting, this two-fluid instrument has the advantages of a long base line tiltmeter. Thermally induced errors, dominant in water-tube tiltmeters, are eliminated by putting two fluids, having densities of different temperature coefficients, into a dual tube so that the fluids experience the same thermal environment. By measuring the heights of the fluids at two stations, a correction for thermally induced error can be determined. This correction is then applied to the measured difference in the height of one fluid between stations to yield the true difference in elevation. Laboratory-induced thermal errors of as much as 45 mm caused by temperature changes of 30° C in a 2-m section were reduced to zero after applying this correction. This test was quite dramatic and clearly indicates the effectiveness of the two-fluid correction technique. The corrected data have a standard deviation from the mean of 0.13 mm. This value could easily be improved by automatic level recording and selection of more optimum fluids. The application of this method allows precise measurements over long base lines (a resolution of about 10 −8 to 10 −9 rad in a 1-km instrument) without expensive level interconnecting tubes or deep burial.
Go, Dog, Go: Maze Training AIBO vs. a Live Dog, An Exploratory Study

The purpose of this study was to investigate differences in interaction and attribution when participants directed either a robotic dog (AIBO) or a live dog. Twenty-nine participants (20 female, 9 male) directed one of the two entities, a live dog or AIBO, through a complex maze from a remote location by providing voice commands. Participants were given identical feedback regarding the entity's performance during the maze task. While directing the dog or AIBO through the maze, participants rated their own moods. Following the maze task, participants rated the dog or AIBO on a variety of attributes. Vocal data were analyzed for content and fundamental frequency. Results indicate that although vocal content and mood ratings did not differ when participants interacted with the dog versus AIBO, fundamental frequency was higher when participants talked to the dog rather than the AIBO. The dog and AIBO were also rated differently on several attributes after the maze task. Overall, the results suggest that human responses during interactions with live and robotic animals can be superficially similar, yet distinctly different when examined at a deeper level.
Reaching Consensus With Increasing Information

This paper focuses on a model of opinion formation over networks with continuously flowing new information and studies the relationship between the network and information structures and agents' ability to reach agreement. At each time period, agents receive private signals in addition to observing the beliefs held by their neighbors in a network. Each agent then updates its belief by aggregating the information available to it in a boundedly rational fashion. Whether this model results in conformity or disparity of beliefs is contingent on connectivity of the network and identifiability of the unknown state. We show that if the network is strongly connected, agents will eventually reach consensus in their beliefs; if in addition the state is globally identifiable, then agents will be able to learn the unknown state. Agents will also reach consensus and learn the state if the network fails to be connected but the state is locally identifiable. In contrast, agents in a non-strongly connected network will almost never reach agreement in their beliefs about a locally unidentifiable state. We also provide a characterization of the rates of convergence in terms of the top Lyapunov exponent of a set of i.i.d. matrices. The proofs use Oseledets' multiplicative ergodic theorem and recent results on stability of Lyapunov regular dynamical systems.
Substrate Distortion to a Boat Conformation at Subsite −1 Is Critical in the Mechanism of Family 18 Chitinases

Using molecular dynamics simulations, we examined the plausible conformations for a hexaNAG substrate bound to the active site of Chitinase A. We find that (i) the hydrolysis mechanism of Chitinase A (a family 18 chitinase from Serratia marcescens) involves substrate distortion, (ii) the first step of acid-catalyzed hydrolysis (protonation of the linking anomeric oxygen between GlcNAc residues −1 and +1) requires a boat conformation for the GlcNAc residue at binding subsite −1; (iii) ab initio quantum mechanical calculations (HF/6-31G**) predict that protonation of a GlcNAc in a boat conformation leads to spontaneous anomeric bond cleavage to yield an oxazoline ion intermediate. We also studied several conformations of two possible hydrolysis intermediates: the oxocarbenium ion and the oxazoline ion. Only the oxazoline ion orients in the enzyme active site so as to allow stereoselective attack by water. This leads to retention of configuration in the anomeric product as observed experimentally. It is pos...
The immunophilin FK506-binding protein modulates Ca2+ release channel closure in rat heart.

1. The nature of the signal that terminates the release of Ca2+ from the cardiac sarcoplasmic reticulum has remained elusive. This study was intended to examine whether FK506-binding protein (FKBP), which is tightly associated to the ryanodine receptor (RyR)/Ca2+ release channel, plays a role in the termination of Ca(2+)-induced Ca2+ release (CICR) in heart. 2. Confocal microscopy and the Ca2+ indicator fluo-3 were used to visualize the elementary release events, i.e. 'Ca2+ sparks' in rat ventricular myocytes under resting or voltage-clamped conditions. Additionally, electrophysiological single-channel recordings, at constant [Ca2+] or during [Ca2+] steps produced by photorelease of caged Ca2+, were obtained from rat cardiac RyRs incorporated in planar lipid bilayers. 3. Inhibition of FKBP by the immunosuppressants FK506 or rapamycin increased the duration of spontaneous or depolarization-evoked Ca2+ sparks 6- to 7-fold. In addition, Ca2+ sparks were seen with two-level amplitudes, corresponding to full and half normal spark amplitude. 4. FK506 potentiated and prolonged electrically stimulated [Ca2+]i transients and contractions, but did not affect the amplitude and kinetics of the L-type Ca2+ channel current. 5. In planar lipid bilayers, FK506 (15 microM) prolonged approximately 7-fold the mean open lifetime of reconstituted single RyRs, induced the appearance of long-lasting subconductance states, and markedly slowed the spontaneous decay of RyR activity elicited by fast and sustained Ca2+ stimuli. The time constant of the spontaneous decay of activity increased from 1.8 s in control to > or = 20 s in the presence of FK506. 6. We conclude that FKBP may afford an intrinsic mechanism to terminate RyR openings and it may thus exert a negative feedback on CICR in heart cells.
Preparation and Characterization of Silica Supported Au−Pd Model Catalysts

Au-Pd bimetallic model catalysts were synthesized as alloy clusters on SiO2 ultrathin films under ultrahigh vacuum (UHV) conditions. The surface composition and morphology were characterized with low energy ion scattering spectroscopy (LEIS), infrared reflection absorption spectroscopy (IRAS), and temperature programmed desorption (TPD). Relative to the bulk, the surface of the clusters is enriched in Au. With CO as a probe, IRAS and TPD were used to identify isolated Pd sites at the surface of the supported Au-Pd clusters. Ethylene adsorption and dehydrogenation show a clear structure-reactivity correlation with respect to the structure/composition of these Au-Pd model catalysts.
An online, non-invasive fluorescence probe for immobilized cell culture process development

Abstract An online, analytical technology was developed that utilized fluorescence to detect cells during an immobilized cell culture process. Chinese hamster ovary (CHO) cells that produced monoclonal antibodies (mAb) were transfected to express green fluorescent protein (GFP), and stable, fluorescence-positive cells were obtained by fluorescence-activated cell sorting (FACS). The immobilized cell culture process was then used to test the effects of sodium butyrate on cells. In this study, cells were cultured in porous, fibrous matrices that were placed in spinner flasks. A lab-scale, perfusion bioreactor with computer-controlled, online fluorescence sensors that continuously detected GFP fluorescence and quantified cell growth was utilized. In addition, the level of GFP fluorescence was used to predict mAb production in the culture without sampling for cell counting and protein analysis. Thus, non-invasive, fluorescence detection of cells provided a rapid, reliable and robust approach for developing an immobilized cell culture process.
It's all connected: Pathways in visual object recognition and early noun learning.

A developmental pathway may be defined as the route, or chain of events, through which a new structure or function forms. For many human behaviors, including object name learning and visual object recognition, these pathways are often complex, multi-causal and include unexpected dependencies. This paper presents three principles of development that suggest the value of a developmental psychology that explicitly seeks to trace these pathways and uses empirical evidence on developmental dependencies between motor development, action on objects, visual object recognition and object name learning in 12 to 24 month old infants to make the case. The paper concludes with a consideration of the theoretical implications of this approach.
Mechanisms of oxygen- and argon-RF-plasma-induced surface chemistry of cellulose

Pure cellulose samples were Ar- and O2-RF-plasma treated under various external plasma parameter conditions. Plasma induced macromolecular chain and pyranosidic ring cleavage mechanisms are discussed based on survey and high resolution ESCA and ATR-FTIR analysis of cellulose, discharge-exposed cellulose, and discharge-exposed and TFAA and PFPH-derivatized cellulose samples. Analyses have also been made of bothin situ andex situ post plasma oxidation reactions. The new plasma created functionalities were identified and their relative ratios were related to plasma parameters. It was found that Ar plasma treatments initiate reactions mainly associated with the cleavage of C1–C2 linkages leading to the formation of C=O and O-CO-O groups, while O2-plasma treatments are associated with more intense pyranosidic ring (C-O-C bonds) splitting mechanisms. As a result of our detailed investigation of the high resolution C1s spectra of cellulose and carbohydrates we have reassigned the nonequivalent carbon bond affiliation (C-OH, C-O-C, and C-C) at 285–287 eV.
Reiterated DNA sequences defining genomic diversity within the species Mycoplasma hyorhinis

Summary Genomic restriction fragments isolated from Mycoplasma hyorhinis and Mycoplasma hyopneumoniae were shown by DNA hybridization and nucleotide sequence analyses to contain sequences common to these two species, as well as another porcine-derived mycoplasma, Mycoplasma flocculare. Intraspecies hybridization experiments using these fragments as probes indicated that the sequence is highly redundant in several strains of M. hyorhinis, but that there is diversity in the sizes of restriction fragments detected among these strains. In contrast, repetition of the sequence was limited in M. hyopneumoniae and M. flocculare, and no homologies to this repeated element were apparent in mycoplasma species isolated from animal hosts other than the swine. The reiterated sequence may reflect intraspecies genomic diversification in M. hyorhinis and its selective presence in otherwise unrelated species raises the possibility that it has been horizontally transmitted between these organisms.
The response to selection for altered conduction velocity in mice.

Conduction velocities from caudal nerves of 5318 mice resulting from bidirectional selection imposed on three different base populations show immediate response to selection which is asymmetrical after a few generations of selection pressure. Realized heritability estimates from the response to selection were similar to previous estimates (from parent offspring regression) and response was realized without alteration of either body weights or tail lengths in the lines. The physiological basis of the response and behavioral differences between the lines will be investigated.
POLITICAL STEREOTYPES AS A FORM OF CONCEPT-MEDIATED GENERALIZATION'

Summary.-This study tested the application of the learning concepts of response hierarchies, and concept-mediated generalization to stereotypes, using political stereotypes as prototypes. The training phase of this study endowed a CVC with a political label of either "conservative" or "liberal." A pairedassociate, anticipation, concept-formation paradigm was used. The training stimuli were sets of six adjectives contained in the previously measured stereotypes. The sets were varied in terms of their hierarchical value or saliency. In a sample of 123 college students, training stimuli with high saliency were associated with greater learning on five dependent measures. When the same subjects were tested for generalization, they generalized all of the belief components comprising either a liberal or conservative stereotype to the nonsense syllable which had been used in earlier training. The ot~g~nal hierarchical arrangements of component beliefs were also present in the generalization data. This investigation involved the application of the principles of response hierarchies and concept-mediated generalization from learning theory to the study of stereotypes and utilized a political stereotype as a prototype. A political stereotype was chosen as an example because it was thought that people were likely to have strong and well defined stereotypes concerning political positions and they were less likely to feel that it was socially unacceptable to generalize about people in the political area. Consequently, valid measures seemed more obtainable than in the area of ethnic stereotypes. Udolf (1973) has demonstrated that a stereotype could be treated as a hierarchy of belief responses. He measured the stereotypes of political conservatives and liberals and found that they could be reliably expressed as a hierarchy of AF scores (AF being the frequency of a belief as a response to the concept of a conservative minus its frequency as a response to the concept of a liberal). The learning situations employed in generalization studies may involve either simple S-R connections or mediated connections. A mediated S-R connection refers to a chain of simple S-R connections in series, with each response producing the stimulus for the subsequent response. The initial stimulus and the final R are overt and the rest of the chain is usually covert (Dollard & Miller, 1950.)
Performance and NOx emissions of a diesel engine fueled with biodiesel-diesel-water nanoemulsions

Abstract The purpose of this research was to investigate the effects of water concentration in a biodiesel nanoemulsion fuel on engine performance and exhaust emissions of a 4-cylinder diesel engine. Biodiesel nanoemulsions containing 5%, 10% and 15% water were used for the engine tests and the results were compared with B5, B20 and certified #2 diesel fuels. Biodiesel nanoemulsions produced lower NO x emissions and soot opacity than B5, B20 and certified #2 diesel fuels. Biodiesel nanoemulsion with 5% water concentration produced engine power and torque values that were similar to the values measured for B5 fuel. Increasing water concentrations in biodiesel nanoemulsions increased the engine brake specific fuel consumption and CO emissions. The rate of NO x reduction was greater than the rate of CO increase when the water concentration in biodiesel nanoemulsions increased from 10% to 15%. These results provided strong evidences on the effects of increasing water concentration in biodiesel emulsions on reducing NO x and soot from a 4-cylinder diesel engine. Emulsified biodiesel fuel is a promising alternative method for reducing harmful emissions from diesel engines without requiring significant engine modifications.
Connexins form functional hemichannels in porcine ciliary epithelium

The expression of connexins in the ciliary epithelium is consistent with gap junctions between the pigmented (PE) and nonpigmented ciliary epithelium (NPE) that form when connexon hemichannels from adjacent cells pair to form a channel. Here we present evidence that suggests undocked connexons may form functional hemichannels that permit exchange of substances between NPE and the aqueous humor. Intact porcine eyes were perfused via the ciliary artery and propidium iodide (PI) (MW 668) was added to the aqueous humor compartment as a tracer. After calcium-free solution containing PI was introduced into the aqueous humor compartment for 30 min, fluorescence microscopy revealed PI in the NPE cell layer. PI entry into the NPE was inhibited by calcium and by the connexin antagonist 18α-glycyrrhetinic acid (18-AGA). Studies also were carried out with cultured porcine NPE. Under normal conditions, little PI entered the cultured cells but calcium-free medium stimulated PI accumulation and the entry was inhibited by 18-AGA. In cells loaded with calcein (MW 622), calcium-free solution stimulated calcein exit. 18-AGA partially suppressed calcein exit in calcium-free medium. Connexin 43 and connexin 50 proteins were detected by western blot analysis in both native and cultured NPE. In the intact eye, immunolocalization studies revealed connexin 50 at the basolateral, aqueous humor-facing, margin of the NPE. In contrast, connexin 43 was observed at the junction of the PE and NPE layer and on the basolateral membrane of PE. The results point to functional hemichannels at the NPE basolateral surface. It is feasible that hemichannels might contribute to the transfer of substances between the ciliary epithelium cytoplasm and aqueous humor.
From molecules to dynamic biological communities

Microbial ecology is flourishing, and in the process, is making contributions to how the ecology and biology of large organisms is understood. Ongoing advances in sequencing technology and computational methods have enabled the collection and analysis of vast amounts of molecular data from diverse biological communities. While early studies focused on cataloguing microbial biodiversity in environments ranging from simple marine ecosystems to complex soil ecologies, more recent research is concerned with community functions and their dynamics over time. Models and concepts from traditional ecology have been used to generate new insight into microbial communities, and novel system-level models developed to explain and predict microbial interactions. The process of moving from molecular inventories to functional understanding is complex and challenging, and never more so than when many thousands of dynamic interactions are the phenomena of interest. We outline the process of how epistemic transitions are made from producing catalogues of molecules to achieving functional and predictive insight, and show how those insights not only revolutionize what is known about biological systems but also about how to do biology itself. Examples will be drawn primarily from analyses of different human microbiota, which are the microbial consortia found in and on areas of the human body, and their associated microbiomes (the genes of those communities). Molecular knowledge of these microbiomes is transforming microbiological knowledge, as well as broader aspects of human biology, health and disease.
Solid-state alloying in nanostructured binary systems with positive heat of mixing

Abstract While many binary systems exhibit a positive heat mixing that precludes intermixing in conventional bulk diffusion couples, it is possible to alloy in solid state some of these bulk immiscible elements in nanostructures. Molecular dynamics simulations demonstrate that in low-dimensional systems such as surfaces and in sub-nanometer layered superlattice structures, excess enthalpic and entropic energy contributions can provide a driving force for spontaneous intermixing to form substitutional solid solution alloys. Such driving forces diminish, however, in coarser nanophase binary mixtures when domain sizes reach beyond ≈1 nm. In this case, true alloying on the atomic level can be achieved by employing an external forcing mechanism such as severe mechanical deformation. In addition to single-phase alloys, we demonstrate, using X-ray absorption near-edge structure (XANES) analysis, a novel two-phase coexistence controlled by kinetically imposed polymorphic constraints. Using a phenomenological model, possible mechanisms responsible for driven alloying are discussed with reference to several previous proposals in the literature.
Preference for infant-directed speech in preterm infants

The current study explores the effects of exposure to maternal voice on infant sucking in preterm infants. Twenty-four preterm infants averaging 35 weeks gestational age were divided randomly into two groups. A contingency between high-amplitude sucking and presentation of maternal voice was instituted for one group while the other group served as a yoked control. No significant differences were observed in sucking of the two groups, but the degree of pitch modulation of the maternal voice predicted an increase in the rate of infant sucking.
Electron nuclear double resonance studies on heme proteins: interaction of the electron spin with the 57Fe3+ nucleus in metmyoglobin and methemoglobin.

Abstract The electron nuclear double resonance (ENDOR) spectrum from the 57Fe nucleus in high-spin ferric heme was obtained in frozen solutions of metmyoglobin and methemoglobin. Values for the isotropic and anisotropic hyperfine coupling constants were obtained from studies on 57Fe-enriched heme proteins. Small but definite differences between the values of the hyperfine constants for the two proteins were observed.
Mechanisms of spatial competition in marine soft-bottom communities

Two kinds of biogenic structures, roots of seagrasses and tubes of invertebrates, were found to reduce the mobility of a variety of burrowing species, including two polychaetes (Abarenicola pacifica Healy & Wells, A. claparedii Healy & Wells), two bivalves (Macoma nasuta Conrad, Clinocardium nuttalliiConrad), two crustaceans (Upogebia pugettensis (Dana), Callianassa californiensis Dana), a holothurian (Leptosynapta clarkii Heding), and an echinoid (Dendraster excentricus (Eschscholtz)). Comparisons of burrowing in similar sediments showed that: (a) all species had about a two-fold increase in mean time to burial in dense tube-mats of polychaetes and crustaceans; (b) hard-bodied taxa were particularly restricted by roots of Zostera marina L. and were often incapable of penetrating them; (c) roots and tubes together had the greatest impact, with mobility 3 to 37 times slower; and (d) burrowing ability increased when sediments were “pre-burrowed” for 1 day. Comparisons of burrowing rates in different sediments showed effects of physical origin (sediment compaction or sorting). Overall these physical effects were second to those of purely biogenic origin, sediment binding and cohesion by roots and tubes. Nonetheless, physical effects exceeded those of extremely high densities of tube-builders (3160 individuals ·0.01 m−2). In all substrata the movement of larger individuals, and the larger of morphologically similar pairs of species (listed second above), were more restricted by roots and tubes than were smaller ones. The results suggest a general mechanism by which dense assemblages of tube-builders and seagrasses may restrict older and larger burrowing organisms. Because physical properties of the sediment and the abundance of other burrowers are also factors affecting mobility, it is not now possible to predict what situations will render this mechanism of interaction important to natural communities.
Reassessing the Link between Women's Premarital Cohabitation and Marital Quality

Using data from 2,898 women from the National Longitudinal Survey of Youth-1979, we employ a novel method to examine two perspectives, social selection and the experience of cohabitation, commonly used to explain the negative relationship outcomes cohabiting women report. Results reveal cohabitation is negatively related to marital happiness and communication and positively related to conflict. As in previous research, selection mechanisms appear to increase the odds of cohabitation while decreasing marital happiness. A closer examination of the problem also reveals a negative effect of the experience of cohabitation. This paper’s primary contributions are the ability to model selection and experience in the same model and evidence of a robust effect of cohabitation on marital quality. These results underscore the complex pathways between union formation, family structure and marital outcomes.
Electrochemical degradation of quercetin: Isolation and structural elucidation of the degradation products

Abstract This paper reports the first complete isolation, characterization and structural elucidation of 18 intermediates following the electrochemical oxidation of quercetin and provides a mechanism of reaction. Bulk electrolysis was employed to induce the oxidation of quercetin in ethanol–PBS buffered neutral solution (1:1, v/v, pH 7.40). Simultaneous UV–Vis, cyclic and differential pulse voltammetric studies indicated the formation of new products due to the induced electrochemical oxidation of quercetin. Preparative separation and the verification of the oxidized products were achieved using a combination of column chromatography, GC–MS and LC–MS–MS analyses. A possible mechanism for the degradation pathways of quercetin was proposed including an electrochemical step leading to the formation of semi-quinone, ortho -quinone and quinone methide, as well as a chemical step corresponding to the formation of complex degradation products of taxifolin, depside, small phenolic acids, quercetin–ethanol adduct, benzofuronone and dimer.
Fourier spatial filter acts as a temporal gate for light propagating through a turbid medium.

The temporal profiles of ultra-short light pulses propagating through turbid media of different lengths were measured with a streak camera. Various Fourier spatial filters were used to select the spatial frequencies of the scattered pulses. The temporal profiles of the pulses scattered by a 0.4% Intralipid solution in a cell of 5-cm thickness were significantly narrowed because of the removal of the higher-frequency components by a Fourier spatial filter.
Experiences of Forgiveness Among Nonclergy Clients Receiving Residential Psychiatric Treatment

In response to the growing importance focused on forgiveness in clinical work (R. D. Enright, 2000), the relevance of forgiveness to 54 clients receiving inpatient psychiatric treatment was examined. The authors used a reflective questionnaire developed by M. J. Brenneis (2002) to gain a qualitative understanding of forgiveness in the sample. Results indicated that participants primarily defined forgiveness in affective terms, but a sizeable number included behavioral and cognitive components. Some respondents included motivations to forgive and not to forgive as well as the positive impact of forgiveness on relationships. Results are contrasted with the results of M. J. Brenneis's study on clergy. Implications for treatment are discussed.
PROGESTERONE RECEPTORS IN BILATERAL OVARIAN EPENDYMOMA PRESENTING IN PREGNANCY

We present a case of a 25-year-old patient at term pregnancy who presented with a bilateral ovarian neoplasm that was histologically and immunohistochemically indistinguishable from ependymoma of the central nervous system. Progesterone receptors were detected in primary and recurrent neoplasms by immunohistochemistry. This is the first case of this rare neoplasm to present during pregnancy as well as with bilateral ovarian involvement. Together with a previously reported case of recurrent ovarian ependymoma with estrogen and progesterone receptors, this case suggests that hormonal responsiveness of this rare neoplasm may be pathogenically significant.
Measurement and modeling of the millimeter-wave backscatter response of soil surfaces

The millimeter-wave (MMW) backscatter response of bare-soil was examined by conducting experimental measurements at 35 and 94 GHz using a truck-mounted polarimetric scatterometer and by developing appropriate models to relate the backscattering coefficient to the soil's surface and volume properties. The experimental measurements were conducted for three soil surfaces with different roughnesses under both dry and wet conditions. The experimental measurements indicate that in general the backscattering coefficient is comprised of a surface scattering component /spl sigma//sup s/ and a volume scattering component /spl sigma//sup v/. For wet soil conditions, the backscatter is dominated by surface scattering, while for dry conditions both surface and volume scattering are significant, particularly at 94 GHz. Because theoretical surface scattering models were found incapable of predicting the measured backscatter, a semiempirical surface scattering model was developed that relates the surface scattering component of the total backscatter to the roughness parameter ks, where k=2/spl pi///spl lambda/ and s is the rms height, and the dielectric constant of the soil surface. Volume scattering was modeled using radiative transfer theory with the packed soil particles acting as the host material and the air voids as the scattering particles. The combined contribution of surface and volume scattering was found to provide good agreement between the model calculations and the experimental observations.
Technical Note-Approximations to the Renewal Function mt

Models of queuing, inventory, and reliability processes often have a useful renewal process imbedded in the fundamental stochastic process. The number of renewals is sufficient to determine performance measures such as the total cost, shortages, etc. The limit theorems of renewal theory are unsatisfactory in obtaining the expected values of these performance measures over a finite time horizon. This paper compares an accurate numerical technique for calculating the expected number of renewals with an approximation that uses the asymptotic expansion of the dominating residues of the Laplace transform MI¸. Furthermore, when a parameter of the renewal process is uncertain except for its Bayesian prior distribution, an approximation that uses a modified exponential renewal process appears better.
Hypoxia-ischemia induced neurological dysfunction and brain injury in the neonatal rat

Bilateral carotid artery occlusion (BCAO) followed by exposure to a hypoxic condition (8% oxygen for 10 or 15 min) was performed in postnatal day 4 SD rats. Brain injury and myelination changes were examined on postnatal day 21 (P21) and tests for neurobehavioral toxicity were performed from P3 to P21. BCAO followed by 10 or 15 min hypoxic insult resulted in mild and severe, respectively, brain injury, reduction in mature oligodendrocytes and tyrosine hydroxylase positive neurons and impaired myelination as indicated by decreased myelin basic protein immunostaining in the P21 rat brain. Hypoxia-ischemia also affected physical development (body weight gain and eye opening) and neurobehavioral performance, such as righting reflex, wire hanging maneuver, cliff avoidance, locomotor activity, gait analysis, responses in the elevated plus-maze and passive avoidance. BCAO followed by 15 min of hypoxia caused more severely impaired neurobehavioral performance as compared with BCAO followed by 10 min of hypoxia in the rat. The overall results demonstrate that hypoxia-ischemia-induced brain injury not only persists, but also is linked with neurobehavioral deficits in juvenile rats. The present data also indicate that the degree of brain injury and the deficits of neurobehavioral performance in the rat are dependent on the hypoxic-ischemic condition, i.e., the exposure time to hypoxia.
Shifting attention in visual space: The effects of peripheral cueing on brain cortical potentials

The effects of attentional shifts following peripheral cues were studied in humans using event-related potentials (ERPs) and reaction times. Subjects released a key following the presentation of a target preceded by a predictive cue in the same (valid) or the opposite (invalid) visual field, or a bilateral, non-predictive cue. The stimulus onset asynchrony (SOA) separating cue and target was either 200 or 600 ms. Subjects were faster and more accurate when responding to validly cued targets. Attentional modulation of the ERP was manifested as an enhancement of Pl-Nl amplitude at posterior electrode sites following a validly cued target. Furthermore, the latencies of P1, N1 and P3 were significantly shorter in valid trials than in invalid trials. These results only reached significance with the longer SOA, since ERP refractoriness distorted the response evoked by the target when the SOA was only 200 ms. The findings are discussed in the context of previous behavioral and ERP cueing studies.
Factors Associated with Problematic Vocalizations in Nursing Home Residents With Dementia

Purpose of the Study: Problematic vocalizations (PVs) are the most frequent and persistent disruptive behaviors exhibited by nursing home residents with dementia. Understanding factors associated with these behaviors are important to prevent or reduce them. We used the Need-Driven DementiaCompromised Behavior model to identify the characteristics of persons with dementia who are likely to display nonaggressive and aggressive PVs and the conditions under which these behaviors are likely to occur and persist. Design and Methods: This multisite descriptive study included 138 residents of 17 nursing homes, and approximately half had a history of PVs. Background data were gathered through interviews, chart reviews, and administration of physical and neuropsychological assessments. Proximal data were obtained from observations and videotapes. Results: When the 2 subscales of the Verbal Behavior Scale were used as the dependent variables, agreeableness and conscientiousness, positive affect, and discomfort were associated with nonaggressive vocalizations, and general health state (GHS), age, and negative and positive affect were associated with aggressive vocalizations. When the verbally agitated (nonaggressive) section of the Cohen-Mansfield Agitation Inventory was the dependent variable, the background factors of gender, agreeableness, GHS, and age remained predictors, as did the proximal factors of affect and discomfort. Implications: We identified 5 background factors and 3 proximal factors as risk factors for PVs in persons with dementia, with variation between nonaggressive or aggressive PVs. These data provide direction for caregiving for persons with dementia and design of interventions to prevent or reduce PVs.
New Crystalline Silicotitanate (CST) Waste Forms: Hydrothermal Synthesis and Characterization of CS-SI-TI-O Phases

The radioactivity of the Hanford site waste tanks is primarily from {sup 137}Cs and {sup 90}Sr, of which can both be selectively removed from solution using a crystalline silicotitanate (CST) ion exchanger. The authors are currently seeking waste forms alternative to borosilicate glass for Cs-CSTs. In order to obtain a fundamental basis for the development of an alternative waste form, they are investigating synthesis and characterization of CST component phases, namely Cs-Si-Ti-O phases. Two novel Cs-Ti-Si-O phases (one porous, one condensed) have been hydrothermally synthesized, characterized and evaluated as waste form candidates based on chemical and thermal stability, leachability, and ion exchange capabilities.
Separating Models of Learning with Faulty Teachers

We study the power of two models of faulty teachers in Angluin's exact learning model. The first model we consider is learning from equivalence and incomplete membership query oracles introduced by Angluin and Slonim [1]. In this model, the answers to a random subset of the learner's membership queries may be missing. The second model we consider is random persistent classification noise in membership queries introduced by Goldman et al. [2]. In this model, the answers to a random subset of the learner's membership queries are flipped. We show that the incomplete membership query oracle is strictly stronger than the membership query oracle with persistent noise under the assumption that the problem of PAC learning parities with noise is intractable. We also show that under the standard cryptographic assumptions the incomplete membership query oracle is strictly weaker than the perfect membership query oracle. This strengthens the result of Simon [3] and resolves an open question of Bshouty and Eiron [4]. Our techniques are based on ideas from coding theory and cryptography.
Synthesizing stochasticity in biochemical systems

Randomness is inherent to biochemistry: at each instant, the sequence of reactions that fires is a matter of chance. Some biological systems exploit such randomness, choosing between different outcomes stochastically - in effect, hedging their bets with a portfolio of responses for different environmental conditions. In this paper, we discuss techniques for synthesizing such stochastic behavior in engineered biochemical systems. We propose a general method for designing a set of biochemical reactions that produces different combinations of molecular types according to a specified probability distribution. The response is precise and robust to perturbations. Furthermore, it is programmable: the probability distribution is a function of the quantities of input types. The method is modular and extensible. We discuss strategies for implementing various functional dependencies: linear, logarithmic, exponential, etc. This work has potential applications in domains such as biochemical sensing, drug production, and disease treatment. Moreover, it provides a framework for analyzing and characterizing the stochastic dynamics in natural biochemical systems such as the lysis/lysogeny switch of the lambda bacteriophage.
A Model for Teaching Electronic Commerce Students

The teaching of information technology in an ever-changing world at universities presents a challenge. Are courses taught as concepts, while ignoring hands-on courses, leaving the hands-on classes to the technical colleges or trade schools? Does this produce the best employees for industry or give students the knowledge and skills necessary to function in a high-tech world? At Georgia College & State University (GC&SU) a model was developed that combines both concepts and practical hands-on skill to meet this challenge. Using this model, a program was developed that consists of classroom lecture of concepts as well as practical hands-on exercises for mastering the knowledge and developing the skills necessary to succeed in the high-tech world of electronic commerce. The students become productive day one of a new job assignment. This solves the problem of students having the "book knowledge" but not knowing how to apply what has been learned. Ke ywords Teaching model, Electronic commerce students, Team-teaching, ICAPP
A fast approximate algorithm for scaling down digital images in the DCT domain

We present a fast approximate algorithm for scaling down an image by a factor of two, when the input and output streams are both in the form of 8/spl times/8 discrete cosine transform (DCT) transform blocks, as with JPEG coded images. Roughly speaking, the algorithm requires 80% fewer operations than the naive algorithm of inverting the transform, scaling in the spatial domain, and transforming the resulting image.