cssi/SciSciGPT-SciSciNet huggingface dataset:
Variations on the tmRNA gene

tmRNA employs both tRNA-like and mRNA-like properties as it rescues stalled bacterial ribosomes, while targeting the defective mRNA and incomplete nascent protein for degradation. We describe variation of the tmRNA gene (ssrA) and how it informs tmRNA structure and function. Endosymbiont tmRNAs tend to lose secondary structure and length in the mRNA-like region as nucleotide composition drifts with that of the whole genome. A dramatic gene structure variation is circular permutation, which produces two-piece tmRNAs in three bacterial lineages; new sequences blur these lineages. We present evidence that Sinorhizobium two-piece tmRNA retains the 5'-triphosphate of transcriptional initiation and predict a new structure at the 5' end of cyanobacterial two-piece tmRNA precursor. ssrA is a target for some mobile DNAs and a passenger on others. It has been found interrupted (but not functionally disrupted) by mobile elements such as group I introns, genomic islands and palindromic elements. The alphaproteobacterial permuted genes are significantly less frequently interrupted by genomic islands than are their standard counterparts, yet are a hotspot for insertion or swapping of rickettsial palindromic elements, in contrast to other rickettsial loci that show steady decay of a single ancestral element. Bacteriophages, plasmids and genomic islands can carry tmRNA genes; we describe a native bacterial ssrA disrupted by insertion of a genomic island that carries its own ssrA, a genome encoding both one- and two-piece tmRNA, and a phage encoding a tmRNA variant lacking the mRNA-like function, which may counteract host tmRNA during infection.
Color Centers in Alkali Halides at 5°K

This paper reports experimental data on the effect of x-raying NaCl, KCl, and KBr at 5\ifmmode^\circ\else\textdegree\fi{}K (approximately liquid helium temperature). These crystals, grown by Harshaw, were exposed to x-rays (50 kv at 20 and 48 ma) at 5\ifmmode^\circ\else\textdegree\fi{}K, and the absorption spectra were measured from 210 m\ensuremath{\mu} to 1100 m\ensuremath{\mu}. A large concentration of $F$-centers was produced after an exposure of 15 minutes. The $F$-center is narrower than those obtained in additively colored crystals at 20\ifmmode^\circ\else\textdegree\fi{}K. This difference in width also occurs in crystals x-rayed at 78\ifmmode^\circ\else\textdegree\fi{}K. The narrowing of the $F$-band does not seem to be due to the temperature difference, i.e., 5\ifmmode^\circ\else\textdegree\fi{}K and 20\ifmmode^\circ\else\textdegree\fi{}K. No bands were observed to the infrared with the exception of a small ${F}^{\ensuremath{'}}$-band in NaCl and KBr. Bands which were not known previously were obtained to the ultraviolet. Some bands decrease on warming to 78\ifmmode^\circ\else\textdegree\fi{}K while others grow.
Instructor use on online language learning resources: A survey of socio-institutional and motivational factors

In response to the need for research on the contextualized use of CALL resources, the authors conducted a survey on instructor use of a popular online Spanish language learning resource to provide insight into how foreign language instructors’ use of online resources are influenced by socio-institutional factors and instructor motivational factors such as personal background and teaching philosophy. From the 118 survey participants, the authors used quantitative techniques to choose three case studies that represented the diversity of respondents who use the resource in their teaching. They present overall trends and qualitative profiles of the three instructors with the intent to gain an overall understanding of the nature of how the resource is used, not only to provide direction for future quantitative research, but also to illustrate the utility of qualitative research in providing such understanding. Upon analysis of the case studies, the authors conclude that the actual use of a CALL resource may be far from the ideal use the designer intended, and that the use of CALL resources is highly contingent on the sociocultural context of the implementation of the resource. Instructor comments seem to point not towards the physical CALL infrastructure of an instructor’s workplace as a determining factor of resource use, but towards the CALL culture and collegiality of the environment. Most revealing of the nature of an instructor’s use of a resource seems to be the congruence of site features with the instructor’s teaching philosophy, itself the product of a variety of factors.
Juan Bautista Alberdi and his Influence on Immigration Policy in the Argentine Constitution of 1853

Juan Bautista Alberdi is a name not often heard in the United States, even among students of Hispanic-American affairs. Many of his Argentine compatriots and contemporaries are well known to us; we repeat their names as easily as we do those of our own national heroes: Sarmiento, Mitre, Echeverria. Yet the position of Alberdi in the historical development of the Argentine Republic is one of high honor and extreme importance. He is called “The Father of the Argentine Constitution,” and, indeed, such he was. Yet, even more important than this, Alberdi’s arguments in favor of a vast, all-encompassing program of immigration, was the impetus that stimulated his native country and made Argentina the most forward-moving and politically successful nation in Latin America.
Effects of dinoflagellate bioluminescence on the ingestion rates of herbivorous zooplankton

Abstract Ingestion rates of Acartiatonsa (Dana) on highly luminescent cultures of Gonyaulax excavata (Braarud) Balech are reduced by 50–75% relative to cultures with low capacity for luminescence. The effect is particularly noticeable at high cell concentrations. It is suggested that the dense array of flashes surrounding an animal disrupts its swimming and/or feeding patterns. The activity of Acartia clausi at a density of 1 animal/3 ml stimulates 1.1% of the cells' capacity for luminescence each minute. Pseudocalanus minutus stimulates only 0.03% per min, except in rare cases where the animals appear to be much more active. Cirripede and copepod nauplii never stimulate any emission. Favorable conditions for bioluminescence may arise before or during a bloom, and the consequent reduction in grazing may contribute to maintenance of the bloom. Natural concentrations of zooplanktonic organisms cannot exhaust the bioluminescence of healthy Gonyaulax excavata cells.
Strategies for mapping synaptic inputs on dendrites in vivo by combining two-photon microscopy, sharp intracellular recording, and pharmacology

Uncovering the functional properties of individual synaptic inputs on single neurons is critical for understanding the computational role of synapses and dendrites. Previous studies combined whole-cell patch recording to load neurons with a fluorescent calcium indicator and two-photon imaging to map subcellular changes in fluorescence upon sensory stimulation. By hyperpolarizing the neuron below spike threshold, the patch electrode ensured that changes in fluorescence associated with synaptic events were isolated from those caused by back-propagating action potentials. This technique holds promise for determining whether the existence of unique cortical feature maps across different species may be associated with distinct wiring diagrams. However, the use of whole-cell patch for mapping inputs on dendrites is challenging in large mammals, due to brain pulsations and the accumulation of fluorescent dye in the extracellular milieu. Alternatively, sharp intracellular electrodes have been used to label neurons with fluorescent dyes, but the current passing capabilities of these high impedance electrodes may be insufficient to prevent spiking. In this study, we tested whether sharp electrode recording is suitable for mapping functional inputs on dendrites in the cat visual cortex. We compared three different strategies for suppressing visually evoked spikes: (1) hyperpolarization by intracellular current injection, (2) pharmacological blockade of voltage-gated sodium channels by intracellular QX-314, and (3) GABA iontophoresis from a perisomatic electrode glued to the intracellular electrode. We found that functional inputs on dendrites could be successfully imaged using all three strategies. However, the best method for preventing spikes was GABA iontophoresis with low currents (5 to 10 nA), which minimally affected the local circuit. Our methods advance the possibility of determining functional connectivity in preparations where whole-cell patch may be impractical.
Oviductal Fluid Proteins Associated with the Bovine Zona Pellucida and the Effect on In Vitro Sperm-Egg Binding, Fertilization and Embryo Development

Studies have demonstrated that oviductal fluid (ODF) proteins associate with eggs of numerous species including the bovine. In this study, the association of three ODF proteins, the bovine oestrus-associated protein, osteopontin (OPN), lipocalin-type prostaglandin D synthase (L-PGDS), with the bovine zona pellucida (ZP) was demonstrated by immunohistochemistry and western blot. The biological function of ODF derived egg-associated OPN and L-PGDS in sperm binding, fertilization and embryonic development was also explored. In vitro matured bovine oocytes were pre-incubated with ODF collected by cannula from cows in oestrus, or ODF with antibodies to OPN, L-PGDS and bovine serum albumin (BSA). Following incubation, oocytes were inseminated with 1 x 10(5) frozen-thawed spermatozoa, and they were evaluated for sperm binding, fertilization and embryonic development in vitro. Pre-treatment of ODF with antibodies to all of proteins reduced sperm binding to the ZP and fertilization in vitro. Cleavage rates were not significantly different among incubations, but rates of embryo development were significantly decreased. We conclude that antibodies to OPN, L-PGDS and BSA react with oocytes incubated with ODF and inhibit sperm binding, fertilization and embryonic development in vitro, suggesting a potential role of these proteins in these events.
Induction of a heat shock puff by hypoxia in polytene foot pad chromosomes of Sarcophaga bullata.

The single large heat-responsive puff (hs puff) in polytene foot pad cells of fly pupae (Sarcophaga bullata) is shown to be inducible by oxygen deprivation but not, as in other systems, by reoxygenation following an hypoxic treatment. The ambient oxygen concentration must drop below 2% for the hs puff to be maximally induced but the puff is fully inducible and transcriptionally active even in the complete absence of oxygen. Lack of oxygen is also compatible with continued transport of puff materials (formation and dissipation of puff droplets at the hs locus). Hypoxia-induced hs puffs persist indefinitely (>2 days) at maximal or intermediate size and only regress completely after oxygen is resupplied. The induction of the hs puff during hypoxia is highly specific and does not seem to involve activation of any other chromosomal loci, yet the reaction is not confined to the giant foot pad cells or to specific developmental stages. Azide poisoning of cultured foot pads simulates the in vivo effects of hypoxia. The induction of the hs puff by azide, heat, or other means is inhibited by sulfhydryl reagents (iodoacetamide, arsenite) and fluoride, but not by an inhibitor of substrate-linked phosphorylation (arsenate). Instead, arsenate, like other uncouplers (2,4-dinitrophenol) is an inducer of the hs locus. The hs puff can be fully induced by hypoxia at any temperature between 2° and 45° C. The rate of puff expansion is strictly temperature dependent and the temperature characteristics of this process are remarkably similar to those of a promoter RNA polymerase association. The major heat shock protein (hsp-65) in Sarcophaga foot pad cells is also slightly induced during hypoxia and its maximal synthesis during aerobic recovery is no longer completely dependent on concomitant RNA synthesis, indicating that some of the required transcripts are made earlier during hypoxia (presumably at the hs locus).
Generation of new continental crust and terrane accretion in Southeastern Alaska and Western British Columbia: constraints from P- and S-wave wide-angle seismic data (ACCRETE)

Abstract The ACCRETE study addresses the question of continental assemblage in southeastern Alaska and western British Columbia through accretion of exotic terranes and generation of new crust by magmatic addition in a former continental arc. We present results of wide-angle P- and S-wave seismic interpretation of a 300-km long marine-land seismic line across the contacts between accreted terranes and Coast Mountains. Additional constraints on the model are obtained from correlation with geologic mapping. Our results indicate that the Coast Shear Zone (CSZ) is a nearly vertical fault zone probably related to a transpressive regime. West of the CSZ, the mid-Cretaceous (90 Ma) thrust belt is rooted in the deep crust and is truncated by the CSZ. From the interpretation of the imaged sub-vertical reflecting zones, we infer the positions of the Alexander–Wrangellia terrane boundary (AWB) and of Tertiary extensional grabens within Dixon Entrance near its intersection with the profile. The observed values of Vp and Vp/Vs in the lower crust of the Alexander terrane are similar to those of oceanic crust and distinctly different from the Coast Mountains Batholith (CMB) to the northeast. The crust under the CMB (32 km) is thinner than the average continental crust, and the Moho is sharp (∼200 m) and highly reflective. The low-velocity mantle (7.9 km/s) suggests high temperature consistent with the stability of garnet in mafic rocks in the lower crust. The lower crustal velocity of 6.9 km/s supports a lower crust composed of interlayered garnet pyroxene granulite and quartzofeldspathic-restite related to batholith generation. The crustal section under the CMB is seismically identical to the lower two thirds of normal crust, heated and inflated by intrusions of tonalite, and gabbro interlayered with restites from batholith generation and uplifted during exhumation.
A Transition Program for Underprepared Students in General Chemistry: Diagnosis, Implementation, and Evaluation

We developed an online exam to diagnose students who are underprepared for college-level general chemistry and implemented a program to support them during the general chemistry sequence. This transition program consists of extended-length recitations, peer-led team-learning (PLTL) study groups, and peer-mentoring groups. We evaluated this program's impact on student performance in general chemistry using data from the fall semesters 2007, 2008, and 2009. We found that our transition program helped the underprepared students make significant gains in their course performance relative to other students when controlling for prior content knowledge and experience. PLTL did improve the performance of the underprepared students relative to other students in the lower 40% of the class. Inclusion of peer mentoring resulted in additional gains over the use of PLTL. Via surveys to students in the transition program, students agreed or strongly agreed that extended-length recitations and peer-mentoring groups improved their performance in general chemistry. This is important given the voluntary nature of our program.
Genetic studies of free-ranging macaques of Cayo Santiago II. 6-Phosphogluconate dehydrogenase and NADH-methemoglobin reductase (NADH-diaphorase)

For the population of 395 semi-free-ranging rhesus macaques (Macaca mulatta) that inhabited Cayo Santiago in 1976, 6-phosphogluconate dehydrogenase phenotypes of 378 animals were determined. Three phenotypes, controlled by two autosomal codominant alleles,PGDA andPGDB, were found by electrophoretic methods. The frequencies of the alleles are 0.898 and 0.102, respectively. The population, composed of five troops and peripheral males, is in Hardy-Weinberg equilibrium at this locus. The allele frequencies at the 6-phosphogluconate dehydrogenase locus in the population in 1976 were compared with frequencies in 1973; a statistically significant difference was found in one troop. The phenotypes of NADH-methemoglobin reductase (NADH-diaphorase) were determined electrophoretically for 372 animals. These phenotypes are probably the products of two autosomal codominant alleles,Dia1 andDia2, with frequencies of 0.786 and 0.214, respectively. The population is in equilibrium at this locus also. Tests of homogeneity at the dehydrogenase and reductase loci indicate that the allele frequencies are significantly different among the five troops in the population. Observed and expected phenotypic ratios in progeny were compared at the dehydrogenase and the reductase loci. The only significant deviation from expectation occurs among offspring of mothers heterozygous at the reductase locus. The observed distributions of alleles at the 6-phosphogluconate dehydrogenase locus and the NADH-methemoglobin reductase locus are probably the results of stochastic processes.
Butyrophilin of milk lipid globule membrane contains N-linked carbohydrates and cross-links with xanthine oxidase

Abstract 1. 1. N-glycanase, but not O-glycanase, released carbohydrates from butyrophilin of rat and cow milk lipid globule membranes. 2. 2. 1-Deoxynojirimycin, and inhibitor of glucosidases I and II of the glycoprotein processing pathway, increased the amount or extent of glycosylation of butyrophilin in rat milk lipid globules. 3. 3. Butyrophilin and xanthine oxidase of milk lipid globule membrane had a nearest neighbor relationship, as demonstrated through specific crosslinking of these proteins. 4. 4. From these results it is suggested that butyrophilin has asparagine-linked oligosaccharides which bypass the processing apparatus of endoplasmic reticulum and Golgi apparatus. Butyrophilin may be responsible for anchoring xanthine oxidase to the inner (cytoplasmic) face of milk lipid globule membrane.
Current Endoscopic Treatment of Dysphonia

Benign laryngeal disorders result in dysphonia because of effects on glottic closure and the vibratory characteristics of the true vocal fold. Treatment is initially directed at reversing medical conditions and patterns of abuse with surgery reserved for unresolving lesions resulting in troublesome dysphonia. Benign lesions that require surgery are excised as precisely as possible sparing overlying mucosa and the underlying vocal ligament. Vocal fold scarring is currently best treated by augmentation procedures, and atrophy may be compensated for by medialization thyroplasty or by adding bulk to the affected folds. Application of current knowledge of laryngeal histology and physiology is prerequisite to endoscopic surgical intervention.
Tissue concentrations of prostate-specific antigen in prostatic carcinoma and benign prostatic hyperplasia

Prostate-specific antigen (PSA), as measured in peripheral blood, is currently the most widely used marker for the assessment of tumor burden in the longitudinal study of patients with carcinoma of the prostate (PCA). Studies from other laboratories have led to the conclusion that a given volume of PCA causes a much higher level of PSA in the peripheral circulation of patients than a similar volume of prostate without carcinoma. We have evaluated PSA in the resected tissues immunohistochemically and in extracts of PCA and of prostates resected because of benign prostatic hyperplasia (BPH) with an enzyme-linked immunosorbent assay. Immunohistochemical results were less quantitative than but consistent with the results of the ELISA of tissue extracts. Immunohistochemically, there was considerable heterogeneity in the expression of PSA by both PCA and BPH both within and among prostatic tissues from different patients. While the levels of expression of PSA in these tissues overlap broadly, PSA is expressed at a lower level in PCA than in BPH when PSA is expressed as a function of wet weight of tissue (p = 0.0095), wet weight of tissue/% epithelium (p less than 0.0001), protein extracted from the tissue (p = 0.0039), or protein extracted/% epithelium (p less than 0.0001).
Metabolism and cholestatic effect of 3α-hydroxy-7ζ-methyl-5β-cholanoic acid

3α-Hydroxy-7ζ-methyl-5β-cholanoic acid (7ζ-methyl-LA) was infused intravenously into bile fistula hamsters to investigate its metabolism and effect on the bile flow as compared with lithocholic acid. Following infusion of the labeled bile acids, bile was collected quantitatively to allow measurement of bile flow and bile acid composition. More than 80% of radioactivity was recovered in bile within 4 hr. 7ζ-Methyl-LA and lithocholic acid in bile were present as the taurine and glycine conjugates; no free bile acids were detected. 7ζ-Methyl-LA was neither hydroxylated nor metabolized to any measurable extent, though lithocholic acid was 7α-hydroxylated to chenodeoxycholic acid (30–45%).
The wettability of fluoro- and chlorocarbon trialkoxysilane films adsorbed on glass and metal surfaces

Abstract Adsorbed films having a wide range of wettabilities were formed on silica, Pyrex, aluminosilicate, α-alumina, steel and gold by trialkoxysilane (and trichlorosilane) compounds. These compounds had the general formulas, RSi(OR) 3 or RSiCl 3 , where R—was a fluorocarbon or a chlorocarbon group and -OR was -OCH 3 or -OCH 2 CH 3 . The fluorocarbon films had γ e values of γ e values of >40 dynes/cm and water contact angles of 80–90 degrees. Film thickness, determined by ellipsometry, was consistently greater than a monolayer of the trialkoxysilane. Desorption experiments suggest that the films were composed of a polysiloxane network along with unhydrolyzed adsorbate, small polysiloxane molecules and solvent.
Dosing to Efficacy with Neurontin: The STEPS Trial

The STEPS (Study of Titration to Effect Profile of Safety) trial, a 16-week, open-label, postmarketing multicenter study, assessed the efficacy of gabapentin as adjunctive therapy in patients with inadequately controlled partial seizures. Inclusion criteria were less restrictive than for Phase III studies, to include a population more representative of the patient population treated in clinical practice. Gabapentin was titrated up to a maximal dosage of 3600 mg/day to achieve seizure control or to tolerability. The efficacy analysis included compliant patients who had completed approximately 16 weeks of therapy (n = 1055); 573 received or = 1800 mg/day. The average decrease in seizure frequency was 61%, the percentage of seizure-free patients was 46.35%, and the percentage of patients with a > or = 50% decrease in seizure frequency was 76.05%. The cumulative percentage of responders and of patients who were seizure free increased with each dosage increase. The results confirm that titration to efficacy is appropriate for adjunctive therapy with gabapentin in patients with partial epilepsy treated in clinical practice.
The effect of training on endurance and the cardiovascular responses of individuals with paraplegia during dynamic exercise induced by functional electrical stimulation.

Endurance for dynamic exercise, cardiac output, blood pressure, heart rate, ventilation, and oxygen consumption was measured in eight individuals with paraplegia at the end of 4-min bouts of exercise on a friction braked cycle ergometer. Movement of the subjects' legs was induced by electrically stimulating the quadriceps, gluteus maximus and hamstring muscles with a computer-controlled biphasic square — wave current at a frequency of 30 Hz. The friction braked cycle ergometer was pedalled at work rates which varied between 0 and 40 W. Measurements were repeated after 3 and 6 months to assess the affect of training. After 3 months of training it was found that endurance increased from 8 min at a work rate of 0 W to 30 min at a work rate of 40 W. Compared to the cardiovascular responses in non-paralyzed subjects, computerized cycle ergometry was found to be associated with higher relative stresses for a given level of absolute work. Mean blood pressure, for example, increased by over 30% during maximal work in individuals with paralysis compared to the typical response obtained for able-bodied subjects. Analysis of the data showed that instead of the 20-30% metabolic efficiency commonly reported for cycle ergometry, the calculated metabolic efficiency during computer-controlled cycle ergometry was only 3.6%.
On the instability in non-abelian gauge theories with constant magnetic flux

Abstract We discuss the stability of Yang-Mills fields in the framework of a sourceless scheme introduced by 't Hooft. We find that abelian magnetic field configurations in Yang-Mills theories are always unstable. A classification for the unstable modes is given.
The Aharonov-Bohm effect in normal metals-non-ensemble averaged quantum transport

Abstract The Aharonov-Bohm effect in normal metal rings together with the associated conductance fluctuations in wires are clear signatures that experiments are now being performed in a quantum regime where conventional transport concepts do not apply. Ensemble averaging and taking the thermodynamic limit should not be used if comparisons to experiments are to be made. It is shown that by varying both the size of the sample as well as the temperature, we can study how ensemble averaging and energy averaging transforms a coherent quantum system into a classical one.
Multiple Media Literacies

There are at least three different types of media literacy, each linked to a different conception of what we mean by the term media. The notion that media are conduits that carry messages points to the need for media content literacy. The idea that media are distinct languages suggests the need for media grammar literacy, that is, understanding the use of production variables within each medium. The conception of media as environments suggests the need to grasp the influence of the relatively fixed characteristics of each medium (medium literacy), both on individual communications and on social processes in general. Medium literacy, in particular, offers some special thought into the origins, problems, and possibilities of the media literacy movement.
Heart Rate Variability: Measurement and Clinical Utility

Electrocardiographic RR intervals fluctuate cyclically, modulated by ventilation, baroreflexes, and other genetic and environmental factors that are mediated through the autonomic nervous system. Short term electrocardiographic recordings (5 to 15 minutes), made under controlled conditions, e.g., lying supine or standing or tilted upright can elucidate physiologic, pharmacologic, or pathologic changes in autonomic nervous system function. Long-term, usually 24-hour recordings, can be used to assess autonomic nervous responses during normal daily activities in health, disease, and in response to therapeutic interventions, e.g., exercise or drugs. RR interval variability is useful for assessing risk of cardiovascular death or arrhythmic events, especially when combined with other tests, e.g., left ventricular ejection fraction or ventricular arrhythmias.
Distortion-based achievability conditions for joint estimation of sparse signals and measurement parameters from undersampled acquisitions

In this paper, we consider an undersampling system model of the form y = A(T(x, θ)) + n, where x is a k-sparse signal, T(·, · is a (possibly non-linear) function specified by a parameter vector θ and acting on x, A is a sensing matrix, and n is additive measurement noise. We consider an information theoretic decoder that aims to recover the sparse signal and the transformation parameter vector jointly, and study the achievability conditions for estimating the underlying signal within a specified l2 distortion for Gaussian sensing matrices. We compare the achievable distortion of the joint estimation process to that of the standard noisy compressed sensing model, where the sparse signal is directly measured with a sensing matrix with the same number of measurements. We also provide a numerical example to illustrate potential applications.
FBXW7 Mutations in Patients with Advanced Cancers: Clinical and Molecular Characteristics and Outcomes with mTOR Inhibitors

Purpose FBXW7 is a tumor suppressor gene responsible for the degradation of several proto-oncogenes. Preclinical data suggest that FBXW7 mutations sensitize cells to mTOR inhibitors. Clinicopathologic characteristics of cancer patients with FBXW7 mutations and their responses to mTOR inhibitors remain unknown.
VARIATION IN DISSOLVED ORGANIC MATTER CONTROLS BACTERIAL PRODUCTION AND COMMUNITY COMPOSITION

An ongoing debate in ecology revolves around how species composition and ecosystem function are related. To address the mechanistic controls of this relationship, we manipulated the composition of dissolved organic matter (DOM) fed to aquatic bacteria to determine effects on both bacterial activity and community composition. Sites along terrestrial to aquatic flow paths were chosen to simulate movement of DOM through catchments, and DOM was fed to downslope and control bacterial communities. Bacterial production was measured, and DOM chemistry and bacterial community composition (using denaturing gradient gel electrophoresis of 16S rRNA genes) were characterized following incubations. Bacterial production, dissolved organic carbon (DOC)-specific bacterial production, and DOC consumption were greatest in mesocosms fed soil water DOM; soil water DOM enhanced lake and stream bacterial production by 320–670% relative to lake and stream controls. Stream DOM added to lake bacteria depressed bacterial production relative to lake controls in the early season (−78%) but not the mid-season experiment. Addition of upslope DOM to stream and lake bacterial communities resulted in significant changes in bacterial community composition relative to controls. In four of five DOM treatments, the bacterial community composition converged to the DOM source community regardless of the initial inoculum. These results demonstrate that shifts in the supply of natural DOM were followed by changes in both bacterial production and community composition, suggesting that changes in function are likely predicated on at least an initial change in the community composition. The results indicate that variation in DOM composition of soil and surface waters influences bacterial community dynamics and controls rates of carbon processing in set patterns across the landscape.
The relationship between bivariate volterra analysis and power series analysis with application to the behavioral modeling of microwave circuits

Volterra nonlinear transfer functions can be used in the behavioral modeling of many nonlinear microwave circuits. They can be developed experimentally, numerically, and, to a limited extent, analytically. This article presents an enhanced analytic method for developing bivariate Volterra nonlinear transfer functions based on their relationship to power series. The technique is applied to the Volterra-series-based behavioral modeling of a MESFET amplifier using experimental characterization of the MESFET.
Stakeholder Perspectives On Public Managed Behavioral Care In Massachusetts

The 2003 survey of Massachusetts behavioral health providers, as well as conference presentations by other key stakeholders, demonstrate continuing high ratings for the Massachusetts Behavioral Health Program. Key issues facing the program include improving integration, state funding cutbacks, movement into performance and outcomes measurement, and concerns about continuing stigma of mental illness. These issues are prevalent in other states that can benefit from the studies and perspectives of the Massachusetts experience.
Patellar tracking patterns measurement by analytical X-ray photogrammetry

Abstract Variants of normal patellar tracking patterns have been implicated in the pathomechanics of patellar chondromalacia. Since these patterns are dependent upon the dynamic interaction of the quadriceps mechanism and knee geometry, a method for measuring three-dimensional patellar displacement during knee motion is needed before patellar pathomechanics can be fully understood. Once this information is available, a more rational basis for adjusting abnormal tracking patterns can be formulated. A method for accurately measuring patellar displacements using X-ray photogrammetry has been developed. Stainless steel 1 mm balls are implanted percutaneously into the patella and distal femur to provide a radiopaque landmark system which represents the two structures. In order to provide optimal measurement geometry, an analytical photogrammetry system is used. This means that the perspective centers of the X-ray anodes must be calculated before the three-dimensional space coordinates of each landmark can be determined. The displacements between the patella and femoral condyles are derived by computing the relative motion between their respective ball systems. Anterior-posterior, medial-lateral and tilting displacements of the patella were determined for the valgus osteotomy patients shown in this research. The positional accuracy of the patella can be determined by comparing distances between two fixed points (steel balls) in one position with the same distances as computed independently from the other positions. The mean square error is a measure of the patellar position accuracy. Since the implanted markers remain in place permanently, the repeatability of this reference system for future measurements is assured. This method is applicable to a variety of situations requiring the determination of small, three-dimensional displacements between two rigid structures.
Evaluating the effects of enhanced processivity and metal ions on translesion DNA replication catalyzed by the bacteriophage T4 DNA polymerase

Abstract The fidelity of DNA replication is achieved in a multiplicative process encompassing nucleobase selection and insertion, removal of misinserted nucleotides by exonuclease activity, and enzyme dissociation from primer/templates that are misaligned due to mispairing. In this study, we have evaluated the effect of altering these kinetic processes on the dynamics of translesion DNA replication using the bacteriophage T4 replication apparatus as a model system. The effect of enhancing the processivity of the T4 DNA polymerase, gp43, on translesion DNA replication was evaluated using a defined in vitro assay system. While the T4 replicase (gp43 in complex with gp45) can perform efficient, processive replication using unmodified DNA, the T4 replicase cannot extend beyond an abasic site. This indicates that enhancing the processivity of gp43 does not increase unambiguously its ability to perform translesion DNA replication. Surprisingly, the replicase composed of an exonuclease-deficient mutant of gp43 was unable to extend beyond the abasic DNA lesion, thus indicating that molecular processes involved in DNA polymerization activity play the predominant role in preventing extension beyond the non-coding DNA lesion. Although neither T4 replicase complex could extend beyond the lesion, there were measurable differences in the stability of each complex at the DNA lesion. Specifically, the exonuclease-deficient replicase dissociates at a rate constant, k off , of 1.1 s −1 while the wild-type replicase remains more stably associated at the site of DNA damage by virtue of a slower measured rate constant ( k off 0.009 s −1 ). The increased lifetime of the wild-type replicase suggests that idle turnover, the partitioning of the replicase from its polymerase to its exonuclease active site, may play an important role in maintaining fidelity. Further attempts to perturb the fidelity of the T4 replicase by substituting Mn 2+ for Mg 2+ did not significantly enhance DNA synthesis beyond the abasic DNA lesion. The results of these studies are interpreted with respect to current structural information of gp43 alone and complexed with gp45.
A Climate Policy for the Short and Medium Term: Stabilization or Adaptation?:

An evaluation of analyses sponsored by the predecessor to the U.K. Department for Environment, Food and Rural Affairs (DEFRA) of the global impacts of climate change under various mitigation scenarios (including CO2 stabilization at 550 and 750 ppm) coupled with an examination of the relative costs associated with different schemes to either mitigate climate change or reduce vulnerability to various climate-sensitive hazards (namely, malaria, hunger, water shortage, coastal flooding, and losses of global forests and coastal wetlands) indicates that, at least for the next few decades, risks and/or threats associated with these hazards would be lowered much more effectively and economically by reducing current and future vulnerability to those hazards rather than through stabilization. Accordingly, over the next few decades the focus of climate policy should be to: (a) broadly advance sustainable development (particularly in developing countries since that would generally enhance their adaptive capacity to ...
Techniques in pelvic resection

Resection of tumors of the bony pelvis is one of the more difficult procedures in orthopedic surgery. The depth of the operative field, complex three-dimensional anatomy, and ubiquitous presence of delicate surrounding structures makes these procedures both taxing and time consuming. Approaching pelvic resections requires both a thorough knowledge of the three-dimensional anatomy and a systematic approach to exposure and protection of the structures to be preserved. Because pelvic surgery is fraught with complications under the best of circumstances, deficiencies in either anatomy or approach can lead to devastating consequences. Although the specific order of dissection can be varied based on the dictates of the tumor, an organized approach follows a general direction from anterior to posterior, and from inside to outside. The abdominal wall dissection is performed first, and dissection of the vessels and femoral nerve often follows logically. This will lead the surgeon posteriorly to the sacroiliac joint and the sciatic notch. Completing the intrapelvic dissection allows identification of bony landmarks for osteotomy planning. The extrapelvic approach generally follows. A thoughtful, systematic, detail oriented approach can minimize both intraoperative blood loss and risk of iatrogenic injury to vital surrounding structures.
The Effects of Systemic Packet Loss on Aggregate TCP Flows

The use of parallel TCP connections to increase throughput for bulk transfers is common practice within the high performance computing community. However, the effectiveness, fairness, and efficiency of data transfers across parallel connections is unclear. This paper considers the impact of systemic non-congestion related packet loss on the effectiveness, fairness, and efficiency of parallel TCP transmissions. The results indicate that parallel connections are effective at increasing aggregate throughput, and increase the overall efficiency of the network bottleneck. In the presence of congestion related losses, parallel flows steal bandwidth from other single stream flows. A simple modification is presented that reduces the fairness problems when congestion is present, but retains effectiveness and efficiency.
ITERATE: a conceptual clustering algorithm for data mining

The data exploration task can be divided into three interrelated subtasks: 1) feature selection, 2) discovery, and 3) interpretation. This paper describes an unsupervised discovery method with biases geared toward partitioning objects into clusters that improve interpretability. The algorithm ITERATE employs: 1) a data ordering scheme and 2) an iterative redistribution operator to produce maximally cohesive and distinct clusters. Cohesion or intraclass similarity is measured in terms of the match between individual objects and their assigned cluster prototype. Distinctness or interclass dissimilarity is measured by an average of the variance of the distribution match between clusters. The authors demonstrate that interpretability, from a problem-solving viewpoint, is addressed by the intraclass and interclass measures. Empirical results demonstrate the properties of the discovery algorithm and its applications to problem solving.
Views, Objects, and Databases

Objects provide a useful abstraction in programming languages; views provide a similar abstraction in databases. Since databases provide for persistent and shared data storage, view concepts will avoid problems occurring when persistent objects are to be shared. Direct storage of objects disables sharing.
Landscape factors and hydrology influence mercury concentrations in wading birds breeding in the Florida Everglades, USA

The hydrology of wetland ecosystems is a key driver of both mercury (Hg) methylation and waterbird foraging ecology, and hence may play a fundamental role in waterbird exposure and risk to Hg contamination. However, few studies have investigated hydrological factors that influence waterbird Hg exposure. We examined how several landscape-level hydrological variables influenced Hg concentrations in great egret and white ibis adults and chicks in the Florida Everglades. The great egret is a visual "exploiter" species that tolerates lower prey densities and is less sensitive to hydrological conditions than is the white ibis, which is a tactile "searcher" species that pursues higher prey densities in shallow water. Mercury concentrations in adult great egrets were most influenced by the spatial region that they occupied in the Everglades (higher in the southern region); whereas the number of days a site was dry during the previous dry season was the most important factor influencing Hg concentrations in adult ibis (Hg concentrations increased with the number of days dry). In contrast, Hg concentrations in egret chicks were most influenced by calendar date (increasing with date), whereas Hg concentrations in ibis chicks were most influenced by chick age, region, and water recession rate (Hg concentrations decreased with age, were higher in the southern regions, and increased with positive water recession rates). Our results indicate that both recent (preceding two weeks) hydrological conditions, and those of the prior year, influence Hg concentrations in wading birds. Further, these results suggest that Hg exposure in wading birds is driven by complex relationships between wading bird behavior and life stage, landscape hydrologic patterns, and biogeochemical processes.
Application of describing functions in the transient response analysis of a three-term fuzzy controller

The exponential-input describing function technique is used to investigate the transient response of a fuzzy controller. The rule-base of this fuzzy controller is generated by fuzzy addition and the partitioning of the universes of discourse of its input and output variables is based on an exponential mapping scheme. By using the symmetric features introduced by fuzzy addition in the decision table of the fuzzy control algorithm and the new mapping scheme, the effects of the output error time sequences can be represented by independent multilevel relays and a multiplication junction. Computer simulations on a second-order system confirm the behaviour of this analysis technique. >
Feasibility of Intraprocedural Transluminal Hepatic and Femoral Artery Blood Pressure Measurements as an Alternative Embolization Safety Endpoint When Antireflux Devices Are Used During Lobar Chemoembolization

OBJECTIVE. The purpose of this study was to describe the technique for evaluating hepatic arterial blood pressure changes during lobar chemoembolization using antireflux devices. Intraprocedural femoral and hepatic arterial blood pressures were measured and chemoembolization terminated when significant reduction in the difference occurred. Liver toxicity was evaluated. Eleven patients underwent 24 lobar chemoembolization procedures. Early termination of delivery occurred in 11 of 24 (46%) procedures in which the mean relative reduction in systemic-hepatic arterial pressure differential was 48%. The mean liver toxicity score was 1.2. This compares to delivery of the entire dose in 13 of 24 (54%) procedures in which the mean relative reduction in systemic-hepatic arterial pressure differential was 12% with a mean liver toxicity score of 1.2. CONCLUSION. When antireflux devices are used, intraprocedural assessment of hepatic artery blood pressure changes may be a useful embolization safety endpoint.
Molecular pathogenesis of thyroid nodules and cancer.

Tumours derived from the thyroid follicular epithelium represent an informative model for understanding the molecular pathogenesis of multistage tumourigenesis, which is the prevailing theory on cancer development and progression nowadays. The early stages of thyroid tumour development appear to be the consequence of the activation or ‘de novo’ expression of several proto-oncogenes or growth factor receptors, such as ras, ret, NTRK, met,gsp and the thyrotropin (TSH) receptor. Alterations in the expression pattern of these genes are associated with the development of differentiated neoplasms, ranging from benign toxic adenomas (gsp and TSH receptor), to follicular (ras) and papillary (ret/PTC, NTRK, met) carcinomas. They may all be considered to be early events of thyroid cell transformation and, for some, experimental evidence derived from gene transfer studies supports this hypothesis. Alterations in tumour suppressor genes (p53, Rb) are associated instead with the most aggressive and poorly differentiated forms of thyroid cancer, indicating that, in the thyroid tumourigenic process, they represent late genetic events. Specific environmental factors (iodine deficiency, ionizing radiations) have been shown to play a crucial role in promoting the development of thyroid cancer, influencing both its genotypic and phenotypic features. Interestingly, a high percentage of genetic lesions causing thyroid cancer originate from gene rearrangements and chromosomal translocations (ret/PTC, NTRK, Pax-8/PPARγ) a finding which, being a rare event in most epithelial tumours, makes the molecular pathogenesis of thyroid cancer unique. The uninterrupted flow of information on the molecular genetics of thyroid nodules and cancer will broaden the correlation between genotype and phenotype and will also provide important information for the development of more accurate preoperative diagnostic tools and more efficient treatment choices for the different forms of thyroid cancer.
Mass spectrometric comparison of ordinary and fully deuterated α‐ and β‐carotene

The individual, deuterated, isomeric α- and β-carotenes were isolated from the green alga, Scenedesmus obliquus, cultivated in D2O containing 99·7 to 99·8 atom percent deuterium. Mass spectroscopy showed that both the α- and β-deuterio-carotene preparations contained principally the fully deuterated pigment molecules (C40D56), small quantities of deuterated molecules with one proton (C40D55H) and yet smaller quantities of deuterated molecules with two protons (C40D54H2). From statistical calculations the deuterio-carotene preparations also contained one to several isotopically-substituted deuterio-carotenes of each mass in the mass range 585 to 599 because of variation of the number of 13C and H atoms per molecule. The mass fragmentation of the deuterated pigments was analogous to that of the respective ordinary α- and β-carotene. It indicated that the protons in the C40D55H and C40D54H2 molecules were distributed approximately randomly in various parts of the structure as in the terminal rings and in the ends and central portions of the polyene chain.