cssi/SciSciGPT-SciSciNet huggingface dataset:
Some roles of allelopathic compounds in plant communities

Abstract Banzan Kumazawa reported some 300 years ago in Japan that rain or dew which washes the leaves of red pine (Pinus densiflora) is harmful to crops growing under the pine. De Candolle suggested also in 1832 that certain weeds secrete toxins which inhibit growth of crop plants. Despite these suggestions, it is only in the past 70 years that appreciable research has been done in the field of allelopathy and only in the past 15 years that much research has been directed toward elucidating some of the many roles of allelopathy in ecological processes. Some of the more notable ecological phenomena and processes in which allelopathy has been implicated are: succession, patterning of vegetation, prevention of seed decay prior to germination, inhibition of nitrification by climax ecosystems, dormancy of seeds, promotion of infection by pathogens, and resistance to infection.
Calculation procedure for mass transfer in fuel cells

Abstract An analysis of mass transfer losses, or concentration over-potentials in fuel cells is provided. An elementary theory, based on an equivalent film thickness, as proposed in some texts, is derived. This is followed by a more rigorous theoretical treatment of mass transfer theory, for which the mass transfer factor is obtained as a function of the driving force. The solution for the driving force is derived, for the well-known one-dimensional convection–diffusion problem. It is shown that mass transfer in planar and square geometries approximates this idealised situation. A linearised theory, appropriate for low mass flow rates is also presented. The methodology is illustrated using the simple example of a solid oxide fuel cell (SOFC). It is shown that the simplified theory is only applicable for very dilute binary mixtures. A step-by-step procedure for computing mass transfer in fuel cells is detailed, together with a discussion of the scope and range of application of the results.
Synthesis and spectral properties of poly(arylenevinylene)s incorporating 2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene fragments in the polymer chain

Abstract We report the Wittig reactions of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-xylylenebis(triphenylphosphonium bromide) with terephthalaldehyde, 1,4-naphthalenedicarbaldehyde and 9,10-anthracenedicarbaldehyde. Two sets of model compounds were synthesized. The first consisted of a central fragment of 2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene straddled by two pheaylvinyl, naphthylvinyl or anthrylvinyl units. The second set contained derivatives of distyrylbenzene, distyrylnaphthalene and distyrylanthracene with two methoxygroups in each styryl fragment. The photophysical behavior of the polymers and model compounds was investigated through absorbance, excitation and fluorescence spectroscopy.
Kinetic evidence supports the existence of two halide binding sites that have a distinct impact on the heme iron microenvironment in myeloperoxidase.

Myeloperoxidase (MPO) structural analysis has suggested that halides and pseudohalides bind to the distal binding site and serve as substrates or inhibitors, while others have concluded that there are two separate sites. Here, evidence for two distinct binding sites for halides comes from the bell-shaped effects observed when the second-order rate constant of nitric oxide (NO) binding to MPO was plotted versus Cl - concentration. The chloride level used in the X-ray structure that produced Cl - binding to the amino terminus of the helix halide binding site was insufficient to populate either of the two sites that appear to be responsible for the two phases. Biphasic effects were also observed when the I - ,B r - , and SCN - concentrations were plotted against the NO combination rate constants. Interestingly, the trough concentrations obtained from the bell-shaped curves are comparable to normal plasma levels of halides and pseudohalides, suggesting the potential relevance of these molecules in modulating MPO function. The second-order rate constant of NO binding in the presence of plasma levels of I - ,B r - , and SCN - is 1-2-fold lower compared to that obtained in the absence of these molecules and remains unaltered through the Cl - plasma level. When Cl - exceeded the plasma level, the NO combination rate becomes indistinguishable from the second phase of the bell-shaped curve that was obtained in the absence of halides. Our results are consistent with two halide binding sites that could be populated by two halides in which both display distinct effects on the MPO heme iron microenvironment.
Computer-controlled learning in a simple system

An insect preparation, in which the frequency of discharge of an identified tonic motoneurone can be modified by operant-conditioning, is recommended as a model for a study of cellular neuronal events underlying learning. To facilitate the study of the underlying events, we have developed computer programs for on-line control of training. The discharge pattern of the neurone is analysed continually, trends in mean frequency being recognized automatically. Experiments were conducted on a large number of locusts with the perfected computer programs. Statistically significant shifts are used to trigger the delivery of aversive electric shocks to the preparation. In the increase mode, shocks were correlated with spontaneous decreases in frequency. These were followed, in 68% of preparations, by a stable increase in mean frequency (up-learning) that averaged 140.0%. In the decrease mode, shocks were correlated with spontaneous increases in frequency. These were followed, in 64% of preparations, by a decrease in frequency (down-learning) that averaged 62%. Experimentally raised or lowered frequencies were maintained for periods up to a few hours without, and longer with, reinforcement. The trends could be reversed by applying the reciprocal computer program.
PCR Sampling of disease resistance-like sequences from a disease resistance gene cluster in soybean.

Clusters of Resistance-like genes (RLGs) have been identified from a variety of plant species. In soybean, RLG-specific primers and BAC-fingerprinting were used to develop a contig of overlapping BACs for a cluster of RLGs on soybean linkage group J. The resistance genes Rps2 (Phytophthora stem and root rot) and Rmd-c (powdery mildew) and the ineffective nodulation gene Rj2 were previously mapped to this region of linkage group J. PCR hybridization was used to place two TIR/NBD/LRR cDNAs on overlapping BACs from this contig. Both of the cDNAs were present on BAC 34P7. Fingerprinting of this BAC suggested as many as twelve different RLGs were present. Given the high nucleotide identity shared between cDNAs LM6 and MG13 (>90%), direct sequencing of this region would be difficult. More sequence information was needed about the RLGs within this region before sequencing could be undertaken. By comparing the genomic sequences of cDNAs LM6 and MG13 we identified conserved regions from which oligonucleotide primers specific to BAC 34P7 RLGs could be designed. The nine primer pairs spanned the genomic sequence of LM6 and produced overlapping RLG products upon amplification of BAC 34P7. Amplification products from 12 different RLGs were identified. On average, nucleotide identity between RLG sequences was greater than 95%. Examination of RLG sequences also revealed evidence of additions, deletions and duplications within targeted regions of these genes. Using previously mapped cDNAs we were able to quickly and inexpensively access multiple RLGs within a single specific cluster.
A gas-multiplication telescope detector for low-energy ions

Abstract A new detector has been designed and built for the accelerator mass spectrometry (AMS) system at the MIT BEAMS Laboratory. This gas ionization detector uses the common segmented-anode design to measure energy loss in two sectors. It differs from existing designs in having wire grid anodes rather than flat plates in order to permit gas multiplication of the signals induced by drift electrons from initial ionization of the gas. The detector output for 2.5 MeV ions is easily sufficient to feed conventional pre-amplifiers and is without interfering levels of electronic noise. Initial testing indicates that this detector resolves 14 C 2+ from all other well-defined signal clusters in the E r vs. Δ E spectrum at the level required for operation of the AMS instrument.
Particle filtering with missing frames and its application to video tracking over lossy networks

Many practical scenarios such as video tracking in lossy environment require a robust accurate tracking algorithm with dropped frames. A novel robust approach is proposed for visual tracking in the first part of this paper in the presence of frame loss with the Bayesian Importance Sampling framework based on first-order hidden Markov model (HMM). The graphical methods are firstly used to provide an exact solution for estimation using first-order hidden Markov model (HMM) with dropped frames. We subsequently rely on Sequential Importance Sampling to derive the first-order particle filtering algorithm with missing frames. In the second part of the paper, we promote this result and present that graphical methods can also be used to provide an exact solution to particle filtering with missing frames for an mth-order hidden Markov model (HMM) and cycle-free graphs. The resulting algorithm requires a small number of particles for efficient tracking. Experimental results demonstrate the superiority and robustness of the proposed approach to the standard methods, yet the additional computational time required is negligible.
Clinicopathological Correlates of Pancreatic Intraepithelial Neoplasia: A Comparative Analysis of 82 Cases With and 152 Cases Without Pancreatic Ductal Adenocarcinoma

Pancreatic intraepithelial neoplasia is often associated with pancreatic ductal adenocarcinoma and is presumed to be its precursor. It has been difficult to determine the frequency of these lesions because until recently, there was no consensus regarding the terminology and criteria for their grading. Here we compare the frequency and clinical correlates of pancreatic intraepithelial neoplasia in pancreata involved by ductal adenocarcinoma and in benign ones, using the criteria put forward recently. We evaluated pancreatectomy specimens from 82 patients with ductal adenocarcinoma and 152 patients who underwent pancreatectomy for reasons other than primary malignancy (trauma, pancreatitis, and metastatic tumor to pancreas) for the presence, grade, and number of foci of pancreatic intraepithelial neoplasia. Cases were graded by the highest grade of pancreatic intraepithelial neoplasia focus identified. An average of 5.3 sections of pancreas was available for evaluation (range, 1-28 sections). Overall, the frequency of pancreatic intraepithelial neoplasia lesions in ductal adenocarcinoma patients, including Grade 1A (mucinous duct lesions), was 82%, which was significantly higher than the one in benign pancreata -54%, P <.001. There was a progressive increase from normal pancreata to pancreatitis and to ductal adenocarcinoma in the frequency of overall pancreatic intraepithelial neoplasia lesions (16%, 60%, and 82%, respectively) and Grade 3 pancreatic intraepithelial neoplasia (0%, 4%, and 40%, respectively). In most instances, in any given case of higher-grade pancreatic intraepithelial neoplasia lesion, there were also several foci of lower grade lesions. The frequency of higher-grade pancreatic intraepithelial neoplasia lesions (2 and 3) in pancreata resected for ductal adenocarcinoma was 59%, significantly higher than in those without primary carcinoma (17%). This progressive increase in frequency of pancreatic intraepithelial neoplasia from incidental pancreatectomies (presumed to have a nonpathologic pancreas) to pancreatitis (considered a risk factor for carcinoma) and to ductal adenocarcinoma constitutes an indirect support for the precancerous role attributed to pancreatic intraepithelial neoplasia lesions. The relatively high absolute occurrence of pancreatic intraepithelial neoplasia Grade 1A (mucinous duct lesions) in benign conditions (43%) suggests that this group represents a combination of neoplastic and non-neoplastic lesions.
Spectroscopic Properties and Molecular Structure of 1, 3-Dimethyl-2-(Se, Se-dibromoseleno)-2(3H)-imidazolylidene

Oxidative addition of Br2 to 1,3-dimethyl-2(3H)-imidazoleselone results in a compound that can be viewed as a Se(II) bromide complex with a stabilized imidazolylidene ring as verified by X-ray crystallography. The structure consists of dimeric pairs containing nearly linear Br-Se-Br units bonded through carbon to planar imidazolyidene rings at torsion angles of 91.4° for N1-C1-Se1-Br1 and 76.8° for N3-C6-Se2-Br4. Significant intermolecular contacts between dimeric units are seen through short Se–Se [3.494(1) A] and Se1–Br4 bridging [3.509(1) A]. Solution state Raman data show the characteristic peaks for a linear Br-Se-Br moiety with a strong polarized peak at 158 cm−1 and a weak shoulder at 181 cm−1 corresponding to the symmetric and asymmetric Br-Se-Br stretching modes respectively. In the absence of X-ray data, correlation of structure to vibrational data provides further support for structural speculations in other compounds with the linear SeBr2 grouping. Crystal structure data for C5H8N2Br2Se. Cell ...
Ab Initio Study of the Reactions between a Series of Substituted Singlet Nitrenium Ions and Water

Highly correlated ab initio molecular orbital calculations have been used to study the energetics and mechanisms governing the reactions of a series of substituted singlet nitrenium ions (1[R−N−H]+, R = H, Cl, F, CN, and Me) with water in gas phase and in solution. It was found that, in gas phase and in solution, the nitrenium ions react in a barrierless fashion to produce an intermediate [HNR−OH2]+, which in turn undergoes a 1,2-hydrogen shift to produce the corresponding protonated hydroxylamine [RNH2OH]+. Results obtained at the QCISD(T)/6-311++G**//QCISD/6-311++G** level indicate that in the gas phase, the intermediates are located between 27.7 and 339.6 kJ/mol below the reactants depending upon the substituent on the nitrenium ion. The transition states are located between 93.1 and 141.9 kJ/mol above the intermediates depending upon the substituent in question. Electrostatic interactions with the solvent increases the intrinsic barrier of the process, as it lowers the relative energy of the intermedi...
A method and cost model for treatment of water extracted during geologic CO2 storage

Extraction of water as a part of CO2 storage may be desirable for risk management and process optimization. Treatment and repurposing of this water creates a useful resource and reduces the volumes that must otherwise be disposed. To better understand the tradeoff of costs versus processes and risks, we use a systems approach to evaluate treatment costs that are reasonable for the chemical and physical qualities (salinity, temperature, pH and turbidity) of water that could be extracted from target geologic formations. We evaluate primary and secondary pretreatments, membrane desalination processes (reverse osmosis and nanofiltration), thermal processes (multiple effect distillation and multi-stage flash distillation), and several concentrate (brine) disposal methods. The results indicate that for waters extracted from storage sites, salinities and temperatures may often be higher than for municipal treatment scenarios. Thus, thermal treatment methods are more cost-feasible than membrane methods in many cases, although pressure recovery methods for reverse osmosis can mitigate this. Treatment costs including concentrate disposal fall within a range of US$0.50–2.50/ton CO2 injected, although some costs can be much higher (up to US$30/ton CO2 under certain concentrate disposal cost ranges). A sensitivity analysis shows that temperature is the most important in determining costs followed by selection of concentrate disposal method.
Pepsinogen C: a type 2 cell-specific protease

Pepsinogen C, also known as progastricsin or pepsinogen II, is an aspartic protease expressed primarily in gastric chief cells. Prior microarray studies of an in vitro model of type 2 cell differentiation indicated that pepsinogen C RNA was highly induced, comparable to surfactant protein RNA induction. Using second-trimester human fetal lung, third-trimester postnatal and adult lung, and a model of type 2 cell differentiation, we examined the specificity of pepsinogen C expression in lung. Pepsinogen C RNA and protein were only detected in >22 wk gestation samples of neonatal lung or in adult lung tissue. By immunohistochemistry and in situ hybridization, pepsinogen C expression was restricted to type 2 cells. Pepsinogen C expression was rapidly induced during type 2 cell differentiation and rapidly quenched with dedifferentiation of type 2 cells after withdrawal of hormones. In all samples, pepsinogen C expression occurred concomitantly with or in advance of processing of surfactant protein-B to its mature 8-kDa form. Our results indicate that pepsinogen C is a type 2 cell-specific marker that exhibits tight developmental regulation in vivo during human lung development, as well as during in vitro differentiation and dedifferentiation of type 2 cells.
STUDENTS' UNDERSTANDING OF THREE-DIMENSIONAL RECTANGULAR ARRAYS OF CUBES

The present study extends previous research in this area by providing a more elaborate and theoretical description of students' solution strategies and errors in dealing with 3-D cube arrays. It describes several cognitive constructions and operations that seem to be required for students to conceptualize and enumerate the cubes in such arrays, exploring in depth general cognitive operations such as coordination, integration, and "structuring" as they are manifested in a spatial context. It describes how, in dealing with 3-D rectangular arrays, students' spatial thinking is related to their enumeration strategies. The findings suggest that students' initial conception of a 3-D rectangular array of cubes is as an uncoordinated set of faces. Eventually, as students become capable of coordinating views, they see the array as space filling and strive to restructure it as such. Those who complete a global restructuring of the array use layering strategies. Those in transition use strategies that indicate that their restructuring is local rather than global. Finally, the data suggest that many students are unable to enumerate the cubes in a 3-D array because they cannot coordinate the separate views of the array and integrate them to construct one coherent mental model of the array. This investigation is part of a combined research/curriculum development project in which children's learning is being examined in the context of developing and testing instructional units on 3-D geometry at grades 3, 4, and 5. Viewing learning as a constructive activity, our instructional approach attempts to select sequences of problematic tasks that guide students to build mathematical structures that are more complex,
Tag-geotag correlation in social networks

This paper presents an analysis of the correlation of annotated information unit (textual) tags and geographical identification metadata geotags. Despite the increased usage of geotagging in collaborative tagging systems, most current research focuses on textual tagging alone in solving the tag search problem. This may result in difficulties to search for precise and relevant information within the given tag space. For example, inconsistencies like polysemy, synonyms, and word inflections with plural forms complicate the tag search problem. Therefore, more work needs to be done to include geotag information with existing tagging information for analysis. In this paper, to make geotagging possible to be used in analysis with tagging, we prove that there is a strong correlation between tagging and geotagging information. Our approach uses tag similarity and geographical distribution similarity to determine inter-relationships among tags and geotags. From our initial experiments, we show that the power law is established between tag similarity and geographical distribution similarity: this means that tag similarity and geographical distribution similarity has a strong correlation and the correlation can be used to find more relevant tags in the tag space. The power law confirms that there is an increased relationship between tagging and geotagging and the increased relationship is scalable in size of tags and geotags. Also, using both geotagging and tagging information instead of only tagging, we show that the uncertainty between derived and actual similarities among tags is reduced.
Understanding Social Preference with Simple Tests

Departures from self-interest in economic experiments have recently inspired models of ?social preferences?. We design a range of simple experimental games that test these theories more directly than existing experiments. Our experiments show that subjects are more concerned with increasing social welfare?sacrificing to increase the payoffs for all recipients, especially low-payoff recipients?than with reducing differences in payoffs (as supposed in recent models). Subjects are also motivated by reciprocity: They withdraw willingness to sacrifice to achieve a fair outcome when others are themselves unwilling to sacrifice, and sometimes punish unfair behavior.
Targeting alpha-synuclein with a microRNA-embedded silencing vector in the rat substantia nigra: positive and negative effects.

Abstract Background: Alpha-synuclein (SNCA) downregulation shows therapeutic potential for synucleinopathies, including Parkinson’s disease (PD). Previously we showed that human (h)SNCA gene silencing using a short hairpin (sh)RNA in rat substantia nigra (SN) protects against a hSNCA-induced forelimb deficit, but not dopamine (DA) neuron loss. Furthermore, the shRNA increases cell death in vitro, but the same target sequence embedded in a microRNA30 transcript (mir30-hSNCA) does not. Objective: Examine hSNCA gene silencing using mir30-hSNCA in vivo. Methods: Rats were stereotaxically injected into one SN with adeno-associated virus serotype 2/8 (AAV)-hSNCA, AAV-hSNCA plus AAV-mir30-SNCA or AAV-hSNCA plus a control non-silencing mir30-embedded siRNA and DA neuron markers and associated behavior were examined. Results: AAV2/8-mediated SN hSNCA expression induces a forelimb deficit and tyrosine hydroxylase-immunoreactive (TH-IR) neuron loss. hSNCA gene silencing using mir30-hSNCA protects against this forelimb deficit at 2 m and ameliorates TH-IR neuron loss. Striatal (ST) TH-IR fiber density and DA markers, assessed by western blot, are unaffected by AAV-hSNCA alone. Co-expression of either silencing vector reduces ST TH-IR fibers, panTH in SN and Ser40 phosphorylated TH in SN and ST, but does not affect vesicular monoamine transporter-2. However, hSNCA gene silencing promotes partial TH-IR fiber recovery by 2 m. Co-expression of either silencing vector also induces SN inflammation, although some recovery was observed by 2 m in hSNCA-silenced SN. Conclusion: hSNCA gene silencing with AAV-mir30-hSNCA has positive effects on forelimb behavior and SN DA neurons, which are compromised by inflammation and reduced TH expression, suggesting that AAV2/8-mir30-hSNCA-mediated gene silencing, although promising in vitro, is not a candidate for therapeutic translation for PD.
Fractional Brownian motion and its fractal dimension estimation

A mathematical model of stochastic processes -- fractional Brownian motion -- is addressed. The power-law behaviors of FBM increments are studied in detail for moments, correlation functions, and power spectra. A moment method is proposed to do model testing of fractional Brownian motion. The results of FBM model testing of six simulators show that the covariance matrix transforming algorithm can provide samples with very good approximation of self-affinity. The self-affinity of the FBM samples generated by Fourier transform filtering is not very obvious. The statistical properties of fractal dimension estimation methods are analyzed. The simulation results show that the variance method provides good performance when only estimates of variances with small time lags are used in the least-squares estimation. For the power spectrum method, the bias is not ignorable because of the aliasing and the window effect.
Co-expression of the 5-HT3B subunit with the 5-HT3A receptor reduces alcohol sensitivity

Abstract Allosteric modulation of mouse 5-Hydroxytryptamine3A (5-HT3A) and 5-HT3A/B receptor function by ethanol and trichloroethanol (TCEt) was assessed in HEK293 cells with whole cell patch-clamp electrophysiological recordings. Ethanol enhanced 5-HT3A receptor function, but had no effect on mouse 5-HT3A/B receptor mediated currents. The enhancing action of trichloroethanol (TCEt) on mouse 5-HT3A/B receptor function was much less than that observed in the mouse 5-HT3A receptor. Where alcohol-induced increases in peak amplitude were observed, the slope of the 20–80% rising phase of current onset was also enhanced, suggesting that increases in activation rate may be one mechanism through which alcohols enhance function of the 5-HT3 receptors.
Variations in Os isotope ratios of pyrrhotite as a result of water-rock and magma-rock interaction: Constraints from Virginia Formation-Duluth Complex contact zones

Abstract Os isotope ratios in pyrrhotite-bearing pelitic rocks of the ∼1.85 Ga Virginia Formation are variable, with perturbations linked to the emplacement of the ∼1.1 Ga Duluth Complex. Pyrrhotite in footwall rocks of the contact aureole show evidence for a mixing event at 1.1 Ga involving a low 187Os/188Os fluid. However, because rocks with perturbed pyrrhotite Os isotope ratios occur 1½ km or more from the Duluth Complex, the fluid is unlikely to have been of magmatic origin. Fluid inclusions in layer-parallel quartz veins provide evidence of the involvement of a boiling fluid at temperatures between ∼300 and 400 °C. Analyses of fluid inclusions via LA-ICP-MS show that the fluids contain up to 1.7 wt% Na, 1.1 wt% K, 4330 ppm Fe, 2275 ppm Zn, and 415 ppm Mg. The veins also contain pyrite or pyrrhotite, plus minor amounts of chalcopyrite, bornite, pentlandite, and sphalerite. The Re–Os isotopic ratios of pyrite from the veins indicate that they crystallized from low 187Os/188Os fluids ( Troctolitic and gabbroic rocks of the Partridge River Intrusion, Duluth Complex, are characterized by Os isotope ratios that are indicative of variable degrees of crustal contamination (γOs values of ∼0–543). Xenoliths of carbonaceous and sulfidic pelitic rocks of the Virginia Formation found in the igneous rocks provide evidence that Os was released by organic matter and pyrite in the sedimentary rocks and assimilated by mantle-derived magma. However, residual pyrrhotite produced as a result of pyrite breakdown in the xenoliths is characterized by 187Os/188Os ratios that are much lower than anticipated and similar to those of pyrrhotite in the contact aureole. The Os exchange and addition shown by pyrrhotite in the xenoliths highlight an unusual cycle of Re–Os liberation during devolatilization, kerogen maturation, and pyrite to pyrrhotite conversion (processes that contribute to magma contamination), followed by Os uptake by pyrrhotite during back reaction involving magma and/or fluid characterized by a relatively low 187Os/188Os ratio. The extreme Os uptake recorded by pyrrhotite in the xenoliths, as well as the lesser degree of uptake recorded by pyrrhotite in the contact aureole, is in line with the high Os diffusivity in pyrrhotite experimentally determined by Brenan et al. (2000) . Our data confirm that Os isotope ratios in pyrrhotite-bearing rocks may be readily perturbed. For this reason caution should be exercised in the interpretation of Os isotope ratios in rocks where pyrrhotite may be the primary host of Os.
JCLS: JXTA-Based Collaborative Learning System

Utilizing JXTA platform and adopting P2P structure, a collaborative learning system, JCLS (JXTA-based collaborative learning system), is designed and implemented. JCLS integrates instant messaging and file sharing. The concept of virtual learning community is introduced. The purpose of JCLS lies in helping students and teachers to break through the restrictions of time and space, to communicate conveniently, so that learning efficiency can be improved and study cost can be saved. P2P network structure is applied to education field and it facilitates carrying on further exploration for the networked education.
A neuropathy in goats caused by experimental coyotillo (Karwinskia humboldtiana) poisoning. V. Lesions in the central nervous system.

Twenty-two goats were poisoned with daily oral doses of ground coyotillo fruits and were killed at various times after the first day of dosing. The morphologic features and distribution of lesions in the central nervous system were studied by light microscopy.An axonal dystrophy occurred in several of the goats given high daily doses. Swellings occurred along axons of Purkinje cells in the cerebellum and in the white matter of the spinal cord. There was a fairly close correlation between the occurrence of clinical signs suggestive of the neocerebellar syndrome and the occurrence and distribution of lesions in the cerebellum.
The Selection of Mediation Tactics in Public Sector Disputes: A Contingency Analysis

How do professional mediators decide what tactics to use in public sector disputes? The present study was designed to evaluate the general proposition that mediators tailor their tactics to the particular dispute circumstances. The respondents were 32 mediators working with the Iowa Public Employment Relations Board. Interviews with these mediators were followed by a questionnaire that asked them to rate, for one case, the extent to which the dispute arose from any of 24 sources and the extent to which they used any of 37 mediation tactics. Correlations were calculated between the measures of dispute sources and mediation tactics. These correlations support the hypothesis that mediators adapt their activities to different dispute circumstances. Among the findings: Bargainers' “unrealistic expectations” are positively associated with mediator efforts to change these expectations and with telling the parties their position is unrealistic. Bargainer “hostility” is positively associated with mediator attempts to control hostility by using humor to lighten the atmosphere and by using directive tactics such as pressing hard for concessions. “Too many issues” is positively associated with mediator efforts to simplify the agenda, organize priorities, suggest trade-offs, clarify needs with constituents, and hold long sessions to facilitate compromise. Bargainers who “lack experience/expertise” lead mediators to simplify the agenda and to educate them to the impasse process.
Dissolved organic phosphorus in the coastal ocean: Reassessment of available methods and seasonal phosphorus profiles from the Eel River Shelf

Methods for quantifying total dissolved phosphorus (TDP) were reevaluated. High-temperature ashing/hydrolysis (Ash/Hydrol.) and Acid Persulfate methods were examined for their ability to quantitatively convert a range of organic-P compounds to orthophosphate. The Ash/Hydrol. method recovered on average 99% of organic-P compounds tested, including phosphonates (compounds with C-P bonds). Contrary to concerns voiced in prior studies, we found no P loss due to volatilization in seawater samples. Poor recovery by the Acid Persulfate method was observed for two compound classes: phosphonates and phospholipids. The Ash/Hydrol. method is recommended for routine TDP analyses. The hydrolysis of dissolved organic phosphorus (DOP) during the phosphomolybdate-blue reaction and the subsequent overestimation of dissolved inorganic phosphorus (DIP) have long been a concern. Extent of hydrolysis of standard DOP compounds was evaluated both during this reaction and over long-term acidified (pH 1.0)/refrigerated and unacidified/frozen storage. Eleven of 12 compounds tested hydrolyzed,2% during the phosphomolybdate-blue reaction. Phospholipid, phosphosugar, and nucleotide mono- and diphosphate standards stored acidified/refrigerated over 2.5 months were ,5% hydrolyzed; compounds with higher energy phosphate bonds (e.g., phosphocreatine) hydrolyzed to a greater extent. A natural seawater sample showed no hydrolysis over 80 d, however, suggesting that refrigerated storage of acidified samples is a viable option. Seasonal DOP profiles from the Eel River Shelf quantified by the Ash/Hydrol. and Acid Persulfate methods yielded comparable results, indicating that the DOP pool at this site did not contain significant phospholipids or phosphonates, which are underrecovered by the Persulfate method. Recoveries using a third method, Nitrate Oxidation, were on average 7% lower. Surface-water DOP exceeded DIP in summer and was apparently related to biological productivity, underscoring the need to include organic species when evaluating nutrient limitation and creating nutrient budgets.
Crystal Structures of Poly(ADP-ribose) Polymerase-1 (PARP-1) Zinc Fingers Bound to DNA: STRUCTURAL AND FUNCTIONAL INSIGHTS INTO DNA-DEPENDENT PARP-1 ACTIVITY.

Poly(ADP-ribose) polymerase-1 (PARP-1) has two homologous zinc finger domains, Zn1 and Zn2, that bind to a variety of DNA structures to stimulate poly(ADP-ribose) synthesis activity and to mediate PARP-1 interaction with chromatin. The structural basis for interaction with DNA is unknown, which limits our understanding of PARP-1 regulation and involvement in DNA repair and transcription. Here, we have determined crystal structures for the individual Zn1 and Zn2 domains in complex with a DNA double strand break, providing the first views of PARP-1 zinc fingers bound to DNA. The Zn1-DNA and Zn2-DNA structures establish a novel, bipartite mode of sequence-independent DNA interaction that engages a continuous region of the phosphodiester backbone and the hydrophobic faces of exposed nucleotide bases. Biochemical and cell biological analysis indicate that the Zn1 and Zn2 domains perform distinct functions. The Zn2 domain exhibits high binding affinity to DNA compared with the Zn1 domain. However, the Zn1 domain is essential for DNA-dependent PARP-1 activity in vitro and in vivo, whereas the Zn2 domain is not strictly required. Structural differences between the Zn1-DNA and Zn2-DNA complexes, combined with mutational and structural analysis, indicate that a specialized region of the Zn1 domain is re-configured through the hydrophobic interaction with exposed nucleotide bases to initiate PARP-1 activation.
Nonlinear evolution of a stimulated Brillouin scattering dynamic grating in a fluid

The role played by fluid-dynamic nonlinearity during the evolution of the acoustic grating in stimulated Brillouin scattering is investigated by means of a forced Kuznetsov equation that is valid for simple dielectric fluids. In the nonlinear amplitude regime, the fluid-dynamic nonlinearity provides a bounding mechanism for the grating amplitude, replacing viscosity as the loss mechanism. After sufficiently long applications of the electrostrictive force, the grating takes the form of a traveling wave with a stationary profile. If the incident optical wave is intense enough, the stationary density profile displays a region of large gradient that may be identified as a shock wave. In this regime the amplitude of the grating ceases to be proportional to the incident optical field. The threshold for the onset of significant nonlinear behavior is formulated in terms of a simple inequality.
Efficient schemes for robust IMRT treatment planning

We use robust optimization techniques to formulate an IMRT treatment planning problem in which the dose matrices are uncertain, due to both dose calculation errors and interfraction positional uncertainty of tumour and organs. When the uncertainty is taken into account, the original linear programming formulation becomes a second-order cone program. We describe a novel and efficient approach for solving this problem, and present results to compare the performance of our scheme with more conventional formulations that assume perfect knowledge of the dose matrix.
Have we overemphasized the role of denitrification in aquatic ecosystems? A review of nitrate removal pathways

The removal of nitrogen (N) in aquatic ecosystems is of great interest because excessive nitrate in groundwater and surface water is a growing problem. High nitrate loading degrades water quality and is linked to eutrophication and harmful algal blooms, especially in coastal marine waters. Past research on nitrate removal processes has emphasized plant or microbial uptake (assimilation) or respiratory denitrification by bacteria. The increasing application of stable isotopes and other tracer techniques to the study of nitrate removal has yielded a growing body of evidence for alternative, microbially mediated processes of nitrate transformation. These include dissimilatory (the reduction of nitrogen into other inorganic compounds, coupled to energy producing processes) reduction of nitrate to ammonium (DNRA), chemoautotrophic denitrification via sulfur or iron oxidation, and anaerobic ammonium oxidation (anammox), as well as abiotic nitrate removal processes. Here, we review evidence for the importance of...
COMPENSATORY LARVAL RESPONSES SHIFT TRADE‐OFFS ASSOCIATED WITH PREDATOR‐INDUCED HATCHING PLASTICITY

Many species with complex life histories can respond to risk by adaptively altering the timing of key life history switch points, including hatching. It is generally thought that such hatching plasticity involves a trade-off between embryonic and hatchling predation risk, e.g., hatching early to escape egg predation comes at the cost of increased vulnerability to hatchling predators. However, most empirical work has focused on simply detecting predator-induced hatching responses or on the short-term consequences of hatch- ing plasticity. Short-term studies may not allow sufficient time for hatchlings to exhibit compensatory responses, which may extend to subsequent life stages and could alter the nature of the trade-offs associated with hatching plasticity. In this study, we examine the consequences of predator-induced hatching plasticity through the larval stage to metamor- phosis in the East African reed frog, Hyperolius spinigularis. To do this we conducted an experiment in which we manipulated initial larval size and density (mimicking the effects of egg predators) and the presence of aquatic predators. We expected that predator-induced hatchlings (because they are less developed and smaller) would experience higher per capita predation rates and a longer larval period and thus would exhibit lower survival to meta- morphosis in the presence of aquatic predators than larger, more developed, later hatched larvae. Surprisingly, we found that predator-induced hatchlings survived better, not worse, than hatchlings from undisturbed clutches. These results motivated us to develop a model parameterized from additional experiments to explore whether a combination of mecha- nisms, compensatory growth, and density- and size-specific predation, could give rise to this pattern. Predicted survival probabilities from the model with compensatory growth were consistent with those from the field experiment: early hatched larvae grew more rapidly through vulnerable size classes than later hatched larvae, resulting in higher survival at metamorphosis. Thus, in this system, there does not appear to be a trade-off in vulnerability between egg and larval predators. Instead, our results suggest that the cost that balances the survival benefit of hatching early to evade egg predators arises later in the life history, as a result of smaller size at metamorphosis.
Cost-sharing contracts and efficiency in a two-stage supply chain

This paper proposes an efficiency-enhancing contract mechanism in a two-stage supply chain. The model includes a buyer (the Original Equipment Manufacturer or OEM) who relies on a seller (the supplier) for key components. The self-interested supplier creates a level of capacity before demand is realised, but this level may not be optimal for the supply chain. Furthermore, the self-interested OEM may choose a suboptimal output price. The firms thus create a contract stipulating three factors: the OEM's output price, a fraction of the supplier's capacity costs to be paid by the OEM, and a fixed rebate paid from the supplier to the OEM. These factors can be chosen so that the efficient level of capacity is created, and both the supplier's and OEM's profits increase. Sensitivity analysis is then conducted to indicate the industry characteristics that make this type of contract most effective.
The Arithmetic of Investment Expenses

Recent regulatory changes have brought a renewed focus on the impact of investment expenses on investors’ financial well-being. The author offers methods for calculating relative terminal wealth levels for those investing in funds with different expense ratios. Under plausible conditions, a person saving for retirement who chooses low-cost investments could have a standard of living throughout retirement more than 20% higher than that of a comparable investor in high-cost investments.
Electroabsorption spectroscopy of molecular inorganic compounds

Electroabsorption spectroscopy is known to report directly on the changes in dipole moment and molecular polarizability accompanying electronic excited state formation. Because ground-state excited-state dipole moment changes can be equated with effective one-electron transfer distances, experimental electroabsorption spectroscopy holds exceptional promise as a methodology for investigating light-induced charge transfer processes within inorganic systems. A survey of the available studies, including metal-to-ligand charge transfer, ligandto-metal charge transfer and localized and delocalized 'intervalence' charge transfer studies, is presented. Also surveyed are electroabsorption studies aimed at illuminating selected molecular nonlinear optical responses. A general observation from electroabsorption studies has been that experimentally determined oneelectron transfer distances are less than simple geometric descriptions would predict. Mononuclear transition-metal systems have proven to be good models for...
Enabling autonomic power-aware management of instrumented data centers

Sensor networks support flexible, non-intrusive and fine-grained data collection and processing and can enable online monitoring of data center operating conditions as well as autonomic data center management. This paper describes the architecture and implementation of an autonomic power aware data center management framework, which is based on the integration of embedded sensors with computational models and workload schedulers to improve data center performance in terms of energy consumption and throughput. Specifically, workload schedulers use online information about data center operating conditions obtained from the sensors to generate appropriate management policies. Furthermore, local processing within the sensor network is used to enable timely responses to changes in operating conditions and determine job migration strategies. Experimental results demonstrate that the framework achieves near optimal management, and in-network analysis enables timely response while reducing overheads.
On "spirituality," "religion," and "religions": a concept analysis.

Objective:With increasing research on the role of religion and spirituality in the well-being of cancer patients, it is important to define distinctly the concepts that researchers use in these studies.Method:Using the philosophies of Frege and James, this essay argues that the terms “religion” and “spirituality” denote the same concept, a concept that is identified with the Peace/Meaning subscale of the Functional Assessment of Chronic Illness Therapy — Spiritual Well-being Scale (FACIT-Sp).Results:The term “Religions” denotes the concept under which specific religious systems are categorized.Significance of results:This article shows how muddling these concepts causes researchers to make claims that their findings do not support, and it ends in suggesting that future research must include universal measures of the concept of religion/spirituality in order to investigate further the role of interventions in the spiritual care of people living with cancer.
The role of reactive oxygen metabolites in glomerular disease.

A large body of evidence accumulated over the last decade indicates that partially reduced oxygen metabolites are important mediators of ischemic, toxic, and immune-mediated tissue injury (7, 19, 30, 32, 52, 82). Numerous studies have examined the role of reactive oxygen metabolites in leukocyte­ dependent and -independent models and the biological effects these metabo­ lites have in glomerular pathophysiology (9, 21, 73, 74). In this review, I define the term reactive oxygen metabolites, briefly recount the sequence of events that led to the consideration of these metabolites as important mediators of tissue injury, and present the available evidence in support of the role of reactive oxygen metabolites in glomerular disease, including the recent studies in which the role of intrinsic antioxidant defenses are beginning to be deline­ ated. Oxygen normally accepts four electrons and is converted directly to water. However, partial reduction of oxygen can and does occur in biological systems, which leads to the generation of partially reduced and potentially toxic reactive oxygen intermediates (33, 53). Thus sequential reduction of oxygen along the univalent pathway leads to the generation of superoxide anion, hydrogen peroxide, hydroxyl radical, and water (33, 53).
Local control of peptide conformation: stabilization of cis proline peptide bonds by aromatic proline interactions

In the native state of proteins there is a marked tendency for an aromatic amino acid to precede a cis proline. There are also significant differences between the three aromatic amino acids with Tyr exhibiting a noticeably higher propensity than Phe or Trp to precede a cis proline residue. In order to study the role that local interactions play in these conformation preferences, a set of tetrapeptides of the general sequence acetyl-Gly-X-Pro-Gly-carboxamide (GXPG), where X = Tyr, Phe, Trp, Ala, or cyclohexyl alanine, were synthesized and studied by nmr. Analysis of the nmr data shows that none of the peptides adopt a specific backbone structure. Ring current shifts, the equilibrium constant, the Van't Hoff enthalpy, and the measured rate of cis-trans isomerization all indicate that the cis proline conformer is stabilized by favorable interactions between the aromatic ring and the proline residue. Analysis of the side chain conformation of the aromatic residue and analysis of the chemical shifts of the pyrrolidine ring protons shows that the aromatic side chain adopts a preferred conformation in the cis form. The distribution of rotamers and the effect of an aromatic residue on the cis-trans equilibrium indicate that the preferred conformation is populated to approximately 62% for the Phe containing peptide, 67% for the Tyr containing peptide, and between 75 and 80% for the Trp containing peptide. The interaction is unaffected by the addition of 8M urea. These local interactions favor an aromatic residue immediately preceding a cis proline, but they cannot explain the relative propensities for Phe-Pro, Tyr-Pro, and Trp-Pro cis peptide bonds observed in the native state of proteins. In the model peptides the percentage of the cis proline conformer is 21% GYPG while it is 17% for GFPG. This difference is considerably smaller than the almost three to one preponderance observed for cis Tyr-Pro peptide bonds vs cis Phe-Pro peptide bonds in the protein database.