Subject Parameters Research Articles

The effects of mineral and liquid organic fertilizers on some nutritional characteristics of bell pepper

The economical effect of liquid organic fertilizer on agriculture may be a factor in the extension of its practice in larger areas. The rates of compost required to supply sufficient N requirements might be economically challenging for farmers. Therefore, the organic liquid fertilizers might help in reducing the need of high rates of compost to maintain proper N amount and in reducing the expenses. The objective of this study was to investigate the effects of mineral and liquid organic fertilizers on some nutritional characteristics of bell pepper. Results show that the main effects and interaction between cultivars and fertilizers were not statistically singificant on the subject parameters in this experiment. However, the application of mineral fertilizer resulted in the highest ascorbic acid content in fresh fruits (110.07 mg 100 g -1 ). In comparison with liquid organic fertilizers, mineral fertilizer had higher levels in other parameters such as lipids (8.16 g 100 g -1 ), fruit dry matter (13.39 g 100 g -1 ), K (18.5 g kg -1 ), Ca (0.83 g kg -1 ), Mg (0.98 g kg -1 ), Mn (7.9 mg kg -1 ) and S (0.21 mg kg -1 ). Ascorbic acid, protein and dry matter content were affected by the colour of fruit. Also, a higher ascorbic acid and Ca, acorbic acid and Mg, lipid and Ca contents suggest a positive correlation between these parameters. However mineral fertilizers had more favorable effects on quality of bell pepper, our results indicated that liquid organic fertilizers might be considered sufficient as a source of nutrients in organic growing.

Parametric variation: Null subjects in minimalist theory (review)

Reviewed by: Parametric variation: Null subjects in minimalist theory Barbara Citko Parametric variation: Null subjects in minimalist theory. By Theresa Biberauer, Anders Holmberg, Ian Roberts, and Michelle Sheehan. Cambridge: Cambridge University Press, 2010. Pp. v, 368. ISBN 9780521886956. $110. Parametric variation is a case study in parametric approaches to crosslinguistic variation, as well as an argument in favor of such an approach. It frames the discussion of parameters around various types of null-subject languages (NSLs) and the null-subject parameter (NSP) as the parameter governing their crosslinguistic distribution. The choice of the parameter is very timely; the NSP is arguably one of the most studied parameters to date, but, as the authors acknowledge in the introduction, its status remains highly controversial. The questions that feature prominently throughout the volume are: (i) How do languages differ with respect to what kinds of empty subjects they allow? (ii) How is the extended projection principle satisfied in NSLs? (iii) What does null subjecthood correlate with? (iv) What is the status of parameters in the grammar? and (v) What is the organization of parameters in the grammar? The book starts with an introduction by Ian Roberts and Anders Holmberg. The first part of the introduction gives an overview of the research on null subjects, starting with Apollonius Dyscolus’s observations about Ancient Greek, and sets the scene for the chapters in the volume. The second part turns to the debates surrounding the NSP, and the third part examines the nature of parameters themselves and the architecture of the grammar that contains them. It discusses and counters the arguments that have been levied in the literature against the concept of parameters, focusing on Newmeyer (2004, 2005), to whose criticism the authors respond in most detail, defending a parametric approach against Newmeyer’s rule-based approach or Hawkins’s (2004) performance-based approach. Ch. 1, ‘A deletion analysis of null subjects’ by Roberts, poses the question of whether the subject position in NSLs is occupied by an empty element or remains empty, with the extended projection principle (EPP) feature being checked by rich inflection. Building on Holmberg 2005, Roberts argues against the latter approach, since on minimalist assumptions, null subjects cannot be licensed by features of rich inflectional heads, as these features are not specified in the lexicon and themselves need to be licensed (by features of the subject). He considers the possibility that null subjects undergo incorporation to T, which he treats as a type of Agree between a Probe and a defective Goal containing a proper subset of the features of the Probe, building on his analysis of Romance clitics (cf. Roberts 2010). Ultimately, however, he rejects such an account in favor of a deletion-based one. [End Page 881] Ch. 2, ‘Null subject parameters’ by Holmberg, starts with Rizzi’s (1982) formulation of the NSP, which distinguished different types of NSLs by positing different types of pronominal inflection, but Holmberg reinterprets it as a difference in whether T has an uninterpretable D feature or not, and uses this to capture the distinction between consistent NSLs, such as Italian, and partial NSLs, such as Brazilian Portuguese, Finnish, Icelandic, or Marathi. To derive the two types of null subjects, Holmberg resorts to two mechanisms: Roberts-style incorporation and deletion. Consistent NSLs for him involve incorporation of a defective pronoun lacking a D feature into T. The D feature of T is valued by the null Aboutness-shift topic of the kind proposed by Frascarelli (2007). Partial NSLs, by contrast, do not have a D feature in T, which captures the indefinite interpretation of null subjects in such languages. Holmberg extends the proposal to capture the differences between Icelandic (a partial NSL) and Mainland Scandinavian languages (non-NSLs). Since in both types of languages T lacks D features, further microparameters are necessary. These lie in what types of phi-features reside in T, whether the EPP is checked by the element that values T’s phi-features, and whether the specifier of TP has to be filled by an overt element. The resulting system involves many ‘null-subject microparameters’, captured as features of T heads. Ch. 3, ‘Control into finite clauses in partial null-subject...

Generalized graded unfolding model with structural equation for subject parameters

AbstractThe generalized graded unfolding model (GGUM) is capable of analyzing polytomous scored, unfolding data such as agree‐disagree responses to attitude statements. In the present study, we proposed a GGUM with structural equation for subject parameters, which enabled us to evaluate the relation between subject parameters and covariates and/or latent variables simultaneously, in order to avoid the influence of attenuation. Additionally, an algorithm for parameter estimation is newly implemented via the Markov Chain Monte Carlo (MCMC) method, based on Bayesian statistics. In the simulation, we compared the accuracy of estimates of regression coefficients between the proposed model and a conventional method using a GGUM (where regression coefficients are estimated using estimates of θ). As a result, the proposed model performed much better than the conventional method in terms of bias and root mean squared errors of estimates of regression coefficients. The study concluded by verifying the efficacy of the proposed model, using an actual data example of attitude measurement.

A Multifactor Extension of Linear Discriminant Analysis for Face Recognition under Varying Pose and Illumination

Linear Discriminant Analysis (LDA) and Multilinear Principal Component Analysis (MPCA) are leading subspace methods for achieving dimension reduction based on supervised learning. Both LDA and MPCA use class labels of data samples to calculate subspaces onto which these samples are projected. Furthermore, both methods have been successfully applied to face recognition. Although LDA and MPCA share common goals and methodologies, in previous research they have been applied separately and independently. In this paper, we propose an extension of LDA to multiple factor frameworks. Our proposed method, Multifactor Discriminant Analysis, aims to obtain multilinear projections that maximize the between-class scatter while minimizing the withinclass scatter, which is the same core fundamental objective of LDA. Moreover, Multifactor Discriminant Analysis (MDA), like MPCA, uses multifactor analysis and calculates subject parameters that represent the characteristics of subjects and are invariant to other changes, such as viewpoints or lighting conditions. In this way, our proposedMDA combines the best virtues of both LDA and MPCA for face recognition.

Standard Care, Standards for Care, or Standard of Care?

Standard Care, Standards for Care, or Standard of Care?

Rural Stories about Parental Malediction (based on field materials from Novgorod and Vologda regions)

The narrative repertoire of many folk traditions features stories of children cursed by their parents. These stories can be divided into several groups with adjacent but independent plots: 1) “the substituted child:” here an unclean spirit steals a human child, replacing it with a log, a broom, or a changeling; 2) “the careless promise:” parents make a thoughtless pledge in time of crisis to give their child to the devil, who claims it when the time comes; 3) “redemption through marriage:” a child who has been cursed lives under the floorboards, in the bath house and so on until the time comes to marry. This article will concentrate on the fourth type of story, the child, who as a result of a parental curse disappears into the forest. I will be analyzing its constituent motifs and discussing the popular ideas that inspire them. The discussion is based primarily on field recordings of about seventy texts, as well as printed and archival sources. This group of stories may be defined in two different ways. According to a literal reading, these are narratives where a curse prompts the ensuing narrative, even if the maledictory formula actually appears at the end of the story, causally connecting the motifs in the tale. The second, broader interpretation encompasses all stories about children who wander or are led into the forest, even though an actual malediction may not be mentioned. These expanded subject parameters are possible because informants often tell stories about those who have been cursed in reply to questions about children lost in the forest [e.g. Belozer.-01:14. LMP],(1) or confirm that such children were described as “cursed” [Khvoin.-99:2]. I will examine the theme of children who have been cursed as a collection of related motifs, the quantity and hierarchy of which can vary from one tradition to another and be conditioned by the peculiarities of the performer’s individual narrative repertoire. Let us examine motifs of primary importance before those of secondary significance. The Inciting Incident: The Formula of the Curse

Identification of Intraday Metabolic Profiles during Closed-Loop Glucose Control in Individuals with Type 1 Diabetes

Algorithms for closed-loop insulin delivery can be designed and tuned empirically; however, a metabolic model that is predictive of clinical study results can potentially accelerate the process. Using data from a previously conducted closed-loop insulin delivery study, existing models of meal carbohydrate appearance, insulin pharmacokinetics, and the effect on glucose metabolism were identified for each of the 10 subjects studied. Insulin's effects to increase glucose uptake and decrease endogenous glucose production were described by the Bergman minimal model, and compartmental models were used to describe the pharmacokinetics of subcutaneous insulin absorption and glucose appearance following meals. The composite model, comprised of only five equations and eight parameters, was identified with and without intraday variance in insulin sensitivity (S(I)), glucose effectiveness at zero insulin (GEZI), and endogenous glucose production (EGP) at zero insulin. Substantial intraday variation in SI, GEZI and EGP was observed in 7 of 10 subjects (root mean square error in model fit greater than 25 mg/dl with fixed parameters and nadir and/or peak glucose levels differing more than 25 mg/dl from model predictions). With intraday variation in these three parameters, plasma glucose and insulin were well fit by the model (R(2) = 0.933 +/- 0.00971 [mean +/- standard error of the mean] ranging from 0.879-0.974 for glucose; R(2) = 0.879 +/- 0.0151, range 0.819-0.972 for insulin). Once subject parameters were identified, the original study could be reconstructed using only the initial glucose value and basal insulin rate at the time closed loop was initiated together with meal carbohydrate information (glucose, R(2) = 0.900 +/- 0.015; insulin delivery, R(2) = 0.640 +/- 0.034; and insulin concentration, R(2) = 0.717 +/- 0.041). Metabolic models used in developing and comparing closed-loop insulin delivery algorithms will need to explicitly describe intraday variation in metabolic parameters, but the model itself need not be comprised by a large number of compartments or differential equations.

T-cell epitope polymorphisms of the Plasmodium falciparum circumsporozoite protein among field isolates from Sierra Leone: age-dependent haplotype distribution?

BackgroundIn the context of the development of a successful malaria vaccine, understanding the polymorphisms exhibited by malaria antigens in natural parasite populations is crucial for proper vaccine design. Recent observations have indicated that sequence polymorphisms in the C-terminal T-cell epitopes of the Plasmodium falciparum circumsporozoite protein (Pfcsp) are rather low and apparently stable in low endemic areas. This study sought to assess the pattern in a malaria endemic setting in Africa, using samples from Freetown, Sierra Leone.MethodsFilter-paper blood samples were collected from subjects at a teaching hospital in Freetown during September–October 2006 and in April–May 2007. The C-terminal portion of the Pfcsp gene spanning the Th2R and Th3R epitopes was amplified and directly sequenced; sequences were analysed with subject parameters and polymorphism patterns in Freetown were compared to that in other malaria endemic areas.Results and DiscussionOverall, the genetic diversity in Freetown was high. From a total of 99 sequences, 42 haplotypes were identified with at least three accounting for 44.4% (44/99): the 3D7-type (19.2%), a novel type, P-01 (17.2%), and E12 (8.1%). Interestingly, all were unique to the African sub-region and there appeared to be predilection for certain haplotypes to distribute in certain age-groups: the 3D7 type was detected mainly in hospitalized children under 15 years of age, while the P-01 type was common in adult antenatal females (Pearson Chi-square = 48.750, degrees of freedom = 34, P = 0.049). In contrast, the single-haplotype predominance (proportion > 50%) pattern previously identified in Asia was not detected in Freetown.ConclusionHaplotype distribution of the T-cell epitopes of Pfcsp in Freetown appeared to vary with age in the study population, and the polymorphism patterns were similar to that observed in neighbouring Gambia, but differed significantly at the sequence level from that observed in Asia. The findings further emphasize the role of local factors in generating polymorphisms in the T-cell epitopes of the P. falciparum circumsporozoite protein.

Measurement and modelling of the y-direction apparent mass of sitting human body–cushioned seat system

Laboratory tests were conducted using 13 male subjects seated on a cushioned commercial vehicle driver's seat. The hands gripped a mock-up steering wheel and the subjects were in contact with the lumbar region of the backrest. The accelerations and forces in the y-direction were measured during random lateral whole-body vibration with a frequency range between 0.25 and 30 Hz, vibration magnitudes 0.30, 0.98, and 1.92 m s −2 (unweighted root mean square (rms)). Based on these laboratory measurements, a linear multi-degree-of-freedom (mdof) model of the seated human body and cushioned seat in the lateral direction ( y-axis) was developed. Model parameters were identified from averaged measured apparent mass values (modulus and phase) for the three excitation magnitudes mentioned. A preferred model structure was selected from four 3-dof models analysed. The mean subject parameters were identified. In addition, identification of each subject's apparent mass model parameters was performed. The results are compared with previous studies. The developed model structure and the identified parameters can be used for further biodynamical research in seating dynamics.

Evaluation of Corneal Refraction in a Model of a Gaze Tracking System

The complexity of corneal refraction modeling complicates geometrical analysis of gaze tracking systems. The task can be accomplished in different ways by means of different approximations. Depending on the assumptions made, errors can arise and the accuracy of trackers can end up determined to an excessive degree by the hardware setup and subject parameters. In this study, keeping the hardware and eye model the same, we compare different methods for evaluation of corneal refraction. Our results show that the approximated methods are sensitive to the calibration of the system and less robust to noise. The nonapproximated method removes any dependency on setup and allows clear differentiation between hardware and subject's calibration.

Developmental‐genetic effects on level and change in childhood fears of twins during adolescence

If the adaptive significance of specific fears changes with age, the genetic contribution to individual differences may be lowest at the age of greatest salience. The roles of genes and environment in the developmental-genetic trajectory of five common childhood fears are explored in 1094 like-sex pairs of male and female monozygotic and dizygotic twins assessed on up to three occasions during adolescence (ages 8-18 years). Dichotomous self-ratings of a cluster of five correlated fears from Ollendick's schedule of fears (FSSC-R) were extracted for subjects at each occasion of assessment. The effects of genes and environment on overall level of fears and rates of adolescent decline were explored by fitting an item-response theory ('IRT') model that allowed for individual genetic and environmental differences in initial fear level ('intercept') and rates of adolescent change ('slope') across the repeated waves of measurement. Different forms of the model were explored using Markov Chain Monte Carlo (MCMC) methods to derive the posterior distribution of subject and item parameters from the raw responses. Additive genetic differences affect the common factor underlying the five fear-items. The same genes also affect rates of change with age, especially in boys. Male adolescents with higher overall genetic predisposition to childhood fears tended to show slower recovery with age than subjects with relatively low initial values. Thus, the genetic variance apparently increases with age. This finding is consistent with a prediction that the regulation of genetic differences will be strongest, and thus the additive genetic variance will be smallest, at the age when the particular stimulus is most salient. Items differed in the extent to which they were sensitive to underlying random differences in the rate of developmental change. Individual differences in rates of change with age were more marked in boys than girls.

ANDROLOGY LAB CORNER*: One Semen Sample or 2? Insights From a Study of Fertile Men

ABBIE STOKES-RINER,*SALLY W. THURSTON,* CHARLENE BRAZIL,{DAVID GUZICK,{ FAN LIU,{JAMES W. OVERSTREET,{ CHRISTINA WANG,§AMY SPARKS,5 J. BRUCE REDMON,AND SHANNA H. SWAN{From the *Department of Biostatistics andComputational Biology, University of Rochester,Rochester, New York, (Auger and Jouannet, 1997; Jorgensen et al, 2001, 2002).Center for Health and theEnvironment, Department of Obstetrics and Gynecology,University of California, Davis, California, `Departmentof Obstetrics and Gynecology, University of Rochester,Rochester, New York, §Department of Medicine,Harbor-UCLA Medical Center and Los AngelesBiomedical Research Institute, Los Angeles, California,5Departments of Urology and Obstetrics and Gynecology,University of Iowa, Iowa City, Iowa; andDepartments of Medicine and Urologic Surgery,University of Minnesota, Minneapolis, Minnesota.In clinical settings it is usually recommended that atleast 2 semen samples are obtained, because thisdecreases the error rate in classifying men as fertile,subfertile, or infertile (Berman et al, 1996; World HealthOrganization, 1999; Sharlip et al, 2002). In fact, someauthors have recommended that 3 samples be collectedbecause of the large within-man variability of semenparameters (Keel, 2006).In our prospective study of semen quality in partners ofpregnant women (the Study for Future Families, or SFF),we requested 2 semen samples from each participant inorder to reduce the variability of our estimates of semenquality. However, population studies of semen qualityfrequently collect only 1 sample from each participantIs this optimal when conducting a population study ofsemen quality when resources are limited? If the totalnumber of samples to be collected is fixed, it is preferable,from a purely statistical standpoint, to take a singlesample from as many men as possible, because a largersample size will increase the precision of the populationestimates. From an epidemiologic point of view, it isnecessary to consider whether requesting a second samplewill decrease participation or lead to a less representativestudy population. From a practical standpoint one needsto consider the cost of participant recruitment relative tothe cost of sample analysis. In SFF we found that the costof recruiting a participant far outweighs the cost ofanalyzing the semen sample(s) he provides, and the addedcost for a second sample is relatively minimal. In addition,we found that once a man has agreed to provide 1 semensample he is likely to agree to provide additional samples(88% did).However,ifmultiplesamplesarecollected,andparticularly if the number of samples per man varies, thisraises some statistical issues, which we address here.In this study, we ask 2 questions and use data fromSFF to address these. We consider the appropriatenessof (1) combining data from men who gave 1 sample anddata from men who gave 2 samples in the analysis and(2) combining data from both samples from men whogave 2. For the first question, we ask whether men whogive 1 sample and men who give 2 samples differ, onaverage, with respect to either subject characteristics orsemen parameters. For the second, we ask whethersemen parameters differed, on average, between the firstand second sample among men who gave 2 samples inour study population.

Thigh–calf contact force measurements in deep knee flexion

Knee models often do not contain thigh-calf contact which occurs in deep knee flexion. Thigh-calf contact is expected to reduce muscle forces and thereby affects internal stresses in the knee joint. The purpose of this study was to measure thigh-calf contact forces. Two deep knee flexion activities were selected: squatting and kneeling. Ten healthy subjects participated in the experiment. Contact pressures between the thigh and calf were measured using the Tekscan Conformat pressure mapping sensor. Knee flexion angles were measured unilaterally using an infrared motion capture system. Contact forces were averaged in terms of means and standard deviations. The magnitude and location of the resultant contact force were calculated. Correlations between anthropometric subject parameters and experimental outcome were studied. In general, thigh-calf contact did not take place below 130 degrees knee flexion. The average maximal contact forces for each leg were 34.2% bodyweight during squatting and 30.9% bodyweight during kneeling. Corresponding average maximal knee flexion angles were 151.8 degrees during squatting and 156.4 degrees during kneeling. Thigh and calf circumferences were correlated with the contact force measurements. The current study shows that thigh-calf contact is substantial (>30% bodyweight on one leg) and likely reduces the forces inside the knee during deep knee flexion. Subsequently, total knee replacements may be subjected to lower loads than assumed before, which reduces the risk of implant failure at large flexion angles. Results presented in this study can be utilized in knee models that focus on deep knee flexion.

Testing for Local Dependence in Rasch’s Multiplicative Gamma Model for Speed Tests

The author considers a latent trait model for the response time on a (set of) pure speed test(s), the multiplicative gamma model (MGM), which is based on the assumption that the test response times are approximately gamma distributed, with known index parameters and scale parameters depending on subject ability and test difficulty parameters. Like any other parametric latent trait model, the MGM is based on strong assumptions. One of these assumptions is local independence. Two statistical tests for checking if the local independence assumption holds are compared, using generated and empirical data.

AKA-TPG: A Program for Kinetic and Epidemiological Analysis of Data from Labeled Glucose Investigations Using the Two-Pool Model and Database Technology

The Two-Pool Glucose (TPG) model has an important role to play in diabetes research since it enables analysis of data obtained from the frequently sampled labeled (hot) glucose tolerance test (FSHGT). TPG modeling allows determination of the separate effects of insulin on the disposal of glucose and on the hepatic production of glucose. It therefore provides a basis for the accurate estimation of glucose effectiveness, insulin sensitivity, and the profile of the rate of endogenous glucose production. Until now, there has been no program available dedicated to the TPG model, and a number of technical reasons have deterred researchers from performing TPG analysis. In this paper, we describe AKA-TPG, a new program that combines automatic kinetic analysis of the TPG model data with database technologies. AKA-TPG enables researchers who have no expertise in modeling to quickly fit the TPG model to individual FSHGT data sets consisting of plasma concentrations of unlabeled glucose, labeled glucose, and insulin. Most importantly, because the entire process is automated, parameters are almost always identified, and parameter estimates are accurate and reproducible. AKA-TPG enables the demographic data of hundreds of individual subjects, their individual unlabeled and labeled glucose and insulin data, and each subject's parameters and indices derived from AKA-TPG to be securely stored in, and retrieved from, a database. We describe how the stratification and population analysis tools in AKA-TPG are used and present population estimates of TPG model parameters for young, healthy (without diabetes) Nordic men. Researchers now have a practical tool to enable kinetic and epidemiological analysis of TPG data sets.

Comprehensive processing, display and analysis for in vivo MR spectroscopic imaging

Image reconstruction for magnetic resonance spectroscopic imaging (MRSI) requires specialized spatial and spectral data processing methods and benefits from the use of several sources of prior information that are not commonly available, including MRI-derived tissue segmentation, morphological analysis and spectral characteristics of the observed metabolites. In addition, incorporating information obtained from MRI data can enhance the display of low-resolution metabolite images and multiparametric and regional statistical analysis methods can improve detection of altered metabolite distributions. As a result, full MRSI processing and analysis can involve multiple processing steps and several different data types. In this paper, a processing environment is described that integrates and automates these data processing and analysis functions for imaging of proton metabolite distributions in the normal human brain. The capabilities include normalization of metabolite signal intensities and transformation into a common spatial reference frame, thereby allowing the formation of a database of MR-measured human metabolite values as a function of acquisition, spatial and subject parameters. This development is carried out under the MIDAS project (Metabolite Imaging and Data Analysis System), which provides an integrated set of MRI and MRSI processing functions. It is anticipated that further development and distribution of these capabilities will facilitate more widespread use of MRSI for diagnostic imaging, encourage the development of standardized MRSI acquisition, processing and analysis methods and enable improved mapping of metabolite distributions in the human brain.

The Time Delays of Gravitational Lens HE 0435−1223: An Early‐Type Galaxy with a Rising Rotation Curve

We present Hubble Space Telescope images and 2 years of optical photometry of the quadruple quasar HE 0435� 1223. The time delays between the intrinsic quasar variations aretAD ¼� 14:37 þ0:75 � 0:85 , � tAB ¼� 8:00 þ0:73 � 0:82 ,a nd � tAC ¼� 2:10 þ0:78 � 0:71 days. We also observed nonintrinsic variations of � 0.1 mag yr� 1 that we attribute to micro- lensing. Instead of the traditional approach of assuming a rotation curve for the lens galaxy and then deriving the Hubbleconstant(H0),we assumeH0 ¼ (72 � 7) km s� 1Mpc� 1andderiveconstraintsontherotationcurve.Onthe scale over which the lensed images occur (1B2 ¼ 5 h � 1 kpc ' 1:5Re), the lens galaxy must have a rising rotation curve,anditcannothaveaconstantmass-to-lightratio.Theseresultsaddtotheevidencethatthestructuresofearly- type galaxies are heterogeneous. Subject headingg cosmological parameters — dark matter — galaxies: kinematics and dynamics — gravitational lensing — quasars: individual (HE 0435� 1223)

Effects of Solvent Flow, Dopant Flow, and Lamp Current on Dopant-Assisted Atmospheric Pressure Photoionization (DA-APPI) for LC-MS. Ionizationvia Proton Transfer

In this paper, the effects of solvent flow, dopant flow, and lamp power on proton transfer ionization in dopant-assisted (DA) atmospheric pressure photoionization (APPI) are investigated. A broad theoretical framework is presented, describing the primary photoionization process, the formation of protonated-solvent cluster ions, and the balance between analyte ion creation via proton transfer and loss via recombination. The principal experimental test system utilized methanol as the solvent, toluene as the dopant, and acridine as the analyte. Comparisons are made between acridine and a less basic compound, 9-methylanthracene (9-MA). Experimental determinations of the trends in the analyte MH+ signal and the total ion current (TIC) with variations in the subject parameters are provided. Experimental results and theory demonstrate that both the analyte signal and the TIC approach asymptotic limits with increases in dopant flow and/or lamp current (two factors which dictate the rate of photoion generation). The data show that these limits are lowered at higher solvent flow rates. These results are attributed to the recombination loss process, the rate of which increases with the second power of ion concentration. We deduce that the recombination rate constant increases with solvent flow rate, a consequence of the growth of ion-solvent clusters. Cluster growth is also believed to be a factor in the dramatic loss of sensitivity for 9-MA that occurs as the solvent flow is raised, because larger protonated-solvent cluster ions have greater solvation energies and may be unreactive with compounds having low gas-phase basicity and/or low solvation energy.

The Low‐zIntergalactic Medium. I. OviBaryon Census

Intergalacticabsorbersalonglinesofsighttodistantquasarsareapowerfuldiagnosticfortheevolutionandcontent of the intergalactic medium (IGM). In this study, we use theFar Ultraviolet Spectroscopic Explorer(FUSE) satellite to search 129 known Lyabsorption systems at z < 0:15 toward 31 active galactic nuclei (AGNs) for corresponding absorption from higher Lyman lines and the important metal ions O vi and C iii. We detect O vi in 40 systems, over a smaller range of column density (logNO vi ¼ 13:0 14:35) than seen in H i (logNH i ¼13:0 16:0). The coexistence of OviandHisuggestsamultiphaseIGM withwarmphotoionizedandhotionizedcomponents. Withimproved Ovi detection statistics, we find a steep distribution in O vi column density, dNO vi/dNO vi / N � 2:2� 0:1 O vi , suggesting that numerous weak O vi absorbers contain baryonic mass comparable to the rare strong absorbers. Down to 30 m8 equivalent width (O vi k1032) we find an absorber frequency dNO vi/dz � 17 � 3. The total cosmological mass fraction in this hot gas is at least WHIM ¼ (0:0022 � 0:0003)½h70(ZO/0:1 Z� )( fO vi/0:2)� � 1 , where we have scaled to fiducial values of oxygen metallicity, O vi ionization fraction, and the Hubble constant. Gas in the warm-hot inter- galactic medium (WHIM) at 10 5 -10 6 K contributes at least 4:8% � 0:9% of the total baryonic mass at z < 0:15. We thencombineempiricalscalingrelationsfortheobserved''multiphaseratio,''NH i/NO vi / N 0:9� 0:1 H i ,andforhydrogen overdensity in cosmological simulations, NH i / � 0:7 H , with the H i photoionization correction to derive the mean oxygen metallicity, ZO � (0:09 Z� )( fO vi/0:2) � 1 in the low-z multiphase gas. Given the spread in the empirical relations and in fO vi, the baryon content in the O vi WHIM could be as large as 10%. Our survey is based on a large improvement in the number of O vi absorbers (40 vs. 10) and total redshift path length (z � 2:2 vs. z � 0:5) compared to earlier surveys. Subject headingg cosmological parameters — cosmology: observations — intergalactic medium — quasars: absorption lines

Differences in corneal thickness and corneal endothelium related to duration in Diabetes

This study evaluated the differences of corneal thickness and corneal endothelial morphology in diabetes compared with age-matched, healthy control subjects; in addition, we tested for correlation according to the duration of diabetes. Ultrasound pachymetry and noncontact specular microscopy were performed on 200 patients with diabetes and 100 control subjects. We compared the values for diabetics and normal persons with ANACOVA to adjust for age. Moreover, we examined the correlation between the subject parameters and the duration of diabetes by using a partial correlation coefficient that controlled for age. The diabetic subjects had thicker corneas, less cell density and hexagonality, and more irregular cell size of the corneal endothelium than did the controls (P < 0.05). Central corneal thickness and the coefficient of variation for cell size were significantly higher for diabetes of over 10 years' duration than for diabetes of under 10 years' duration (P < 0.05). The endothelial cell density and percentage of hexagonal cells were lower for diabetes of over 10 years' duration than for diabetes of under 10 years' (P > 0.05). Central corneal thickness was correlated with duration of diabetes (P < 0.05), but corneal endothelial morphology was not (P < 0.05). Those patients with diabetic duration of over 10 years have more corneal morphological abnormalities, especially the coefficient of variation in cell size, compared with the normal subjects. The central corneal thickness was significantly correlated with diabetic duration after controlling for age.