bluuebunny/crossref_metadata_2025 huggingface dataset:
How biased are estimates of extinction probability in revisitation studies?
Authors: KÉRY MARC , SPILLMANN JOHN H. , TRUONG CAMILLE , HOLDEREGGER ROLF
Published: June 2006

Extinction is a fundamental topic for population ecology and especially for conservation and metapopulation biology. Most empirical studies on extinction resurvey historically occupied sites and estimate extinction probability as the proportion of sites where a species is no longer detected. Possible non‐detection of surviving populations is usually not accounted for, which may result in extinction probabilities that are overestimated.

As part of a large revisitation study in north‐east Switzerland, 376 sites with historically known occurrences of a total of 11 plant species 80–100 years ago were visited by two independent observers. Based on typical population size, ramet size and plant architecture, we judged six species as easy to find and five species as hard to find. Using capture–recapture methods to separate non‐detection from true extinction, we gauged the bias of extinction probability estimates that do not account for non‐detection.

When non‐detection was not accounted for, a single visit resulted in an average estimate of population extinction probability of 0.49 (range 0.27–0.67). However, the mean detection probability of a surviving population during a single visit had an estimated average of only 0.81 (range 0.57–1). Consequently, accounting for non‐detection resulted in extinction probability estimates ranging between 0.09 and 0.61 (mean 0.36). Based on a single survey, our revisitation study would have overestimated the extinction rate on average by 11 percentage points (range 5–22%) or by 59% (range 0–250%) relative to the estimated true value.

A simple binomial argument enables the calculation of the minimum required number of visits to detect a surviving population with high probability (e.g. 95%). For the easy to find species, approximately two visits would be required to find most of the surviving populations, whereas up to four visits would be required for the hard to find species.

In revisitation studies, only repeated revisits allow the separation of extinction from simple non‐detection. Unless corrected for possible non‐detection, extinction probability may be strongly overestimated, and hence some control for non‐detection is desirable at least in a subset of species/sites in revisitation studies. These issues are also relevant to the estimation of extinction in metapopulation studies and to the collection of quality data for habitat and distribution models.
Abnormalities of whole body protein turnover, muscle metabolism and levels of metabolic hormones in patients with chronic heart failure
Authors: NØRRELUND H. , WIGGERS H. , HALBIRK M. , FRYSTYK J. , FLYVBJERG A. , BØTKER H. E. , SCHMITZ O. , JØRGENSEN J. O. L. , CHRISTIANSEN J. S. , MØLLER N.
Published: June 2006

Objective.  It is well known that chronic heart failure (CHF) is associated with insulin resistance and cachexia, but little is known about the underlying substrate metabolism. The present study was undertaken to identify disturbances of basal glucose, lipid and protein metabolism.

Design.  We studied eight nondiabetic patients with CHF (ejection fraction 30 ± 4%) and eight healthy controls. Protein metabolism (whole body and regional muscle fluxes) and total glucose turnover were isotopically assayed. Substrate oxidation were obtained by indirect calorimetry. The metabolic response to exercise was studied by bicycle ergometry exercise.

Results.  Our data confirm that CHF patients have a decreased lean body mass. CHF patients are characterised by (i) decreased glucose oxidation [glucose oxidation (mg kg−1 min−1): 1.25 ± 0.09 (patients) vs. 1.55 ± 0.09 (controls), P < 0.01] and muscle glucose uptake [a − v diffglucose (μmol L−1): −10 ± 25 (patients) vs. 70 ± 22 (controls), P < 0.01], (ii) elevated levels of free fatty acids (FFA) [FFA (mmol L−1): 0.72 ± 0.05 (patients) vs. 0.48 ± 0.03 (controls), P < 0.01] and 3‐hydroxybutyrate and signs of elevated fat oxidation and muscle fat utilization [a − v diffFFA (mmol L−1): 0.12 ± 0.02 (patients) vs. 0.05 ± 0.01 (controls), P < 0.05] and (iii) elevated protein turnover and protein breakdown [phenylalanine flux (μmol kg−1 h−1): 36.4 ± 1.5 (patients) vs. 29.6 ± 1.3 (controls), P < 0.01]. Patients had high circulating levels of noradrenaline, glucagon, and adiponectin, and low levels of ghrelin. We failed to observe any differences in metabolic responses between controls and patients during short‐term exercise.

Conclusions.  In the basal fasting state patients with CHF are characterized by several metabolic abnormalities which may contribute to CHF pathophysiology and may provide a basis for targeted intervention.
Control of capsular polysaccharide chain length by UDP‐sugar substrate concentrations in Streptococcus pneumoniae
Authors: Ventura Christy L. , Cartee Robert T. , Forsee W. Thomas , Yother Janet
Published: June 2006

Regulation of chain length is essential to the proper functioning of prokaryotic and eukaryotic polysaccharides. Modulation of polymer size by substrate concentration is an attractive but unexplored control mechanism that has been suggested for many polysaccharides. The Streptococcus pneumoniae capsular polysaccharide is essential for virulence, and regulation of its size is critical for survival in different host environments. Synthesis of the type 3 capsule [‐4)‐β‐d‐Glc‐(1–3)‐β‐d‐GlcUA‐(1‐] from UDP‐glucose (UDP‐Glc) and UDP‐glucuronic acid (UDP‐GlcUA) is catalysed by the type 3 synthase, a processive β‐glycosyltransferase, and requires a UDP‐Glc dehydrogenase for conversion of UDP‐Glc to UDP‐GlcUA. Strains containing mutant UDP‐Glc dehydrogenases exhibited reduced levels of UDP‐GlcUA, along with reductions in total capsule amount and polymer chain length. In both the parent and mutant strains, UDP‐Glc levels far exceeded UDP‐GlcUA levels, which were very low to undetectable in the absence of blocking synthase activity. The in vivo observations were consistent with in vitro conditions that effect chain termination and ejection of the polysaccharide from the synthase when one substrate is limiting. These data are the first to demonstrate modulation of polysaccharide chain length by substrate concentration and to enable a model for the underlying mechanism. Further, they may have implications for the control of chain length in both prokaryotic and eukaryotic polymers synthesized by similar mechanisms.
Phosphatidylglycerol biosynthesis in chloroplasts of Arabidopsis mutants deficient in acyl‐ACP glycerol‐3‐ phosphate acyltransferase
Authors: Xu Changcheng , Yu Bin , Cornish Adam J. , Froehlich John E. , Benning Christoph
Published: June 2006

The biosynthesis of phosphatidylglycerol represents a central pathway in lipid metabolism in all organisms. The enzyme catalyzing the first reaction of the pathway in the plastid, glycerol‐3‐phosphate acyl–acyl carrier protein acyltransferase, is thought to be encoded in Arabidopsis by the ATS1 locus. A number of genetic mutants deficient in this activity have been described. However, the corresponding mutant alleles have not yet been analyzed at the molecular level and a causal relationship between the mutant phenotypes and a deficiency at the ATS1 locus has not been established. The presence in all known ats1 mutants of near wild‐type amounts of phosphatidylglycerol raised the question of whether an alternative pathway of phosphatidylglycerol assembly in the plastid exists. However, detailed analysis of several independent ats1 mutant alleles revealed that all are leaky. Reduction by RNAi of ats1‐1 RNA levels in the ats1‐1 mutant background led to a more severe growth phenotype (small green plants and reduced seed set), but did not decrease the relative amount of phosphatidylglycerol. In contrast, when the amount of ATS2 mRNA encoding the plastidic lysophosphatidic acid acyltransferase catalyzing the second reaction of the pathway was reduced by RNAi in the ats1‐1 mutant background, phosphatidylglycerol amounts decreased, leading to a growth phenotype (small pale‐yellow plants) that is reminiscent of the pgp1‐1 mutant deficient in a late step of plastidic phosphatidylglycerol biosynthesis. These observations indicate coordinated regulation of plastid lipid metabolism and plant development.
Mutations in the eIF(iso)4G translation initiation factor confer high resistance of rice to Rice yellow mottle virus
Authors: Albar Laurence , Bangratz‐Reyser Martine , Hébrard Eugénie , Ndjiondjop Marie‐Noëlle , Jones Monty , Ghesquière Alain
Published: June 2006

We report here evidence of the role that the isoform of the eukaryotic translation initiation factor 4G (eIF(iso)4G) plays in naturally occurring resistance in plant/virus interactions. A genetic and physical mapping approach was developed to isolate the Rymv1 locus controlling the high recessive resistance to Rice yellow mottle virus (RYMV) in the rice (Oryza sativa) variety Gigante. The locus was mapped to a 160‐kb interval containing a gene from the eIF(iso)4G family. The stable transformation of a resistant line with the cDNA of this gene, derived from a susceptible variety, resulted in the loss of resistance in transgenic plants. The allelic variability of this gene was analysed in three resistant and 17 susceptible varieties from different cultivated rice species or subspecies. Compared with susceptible varieties, resistant varieties present specific alleles, characterized by either amino acid substitutions or short amino‐acid deletions in the middle domain of the protein. The structure of this domain was modelled and showed that the substitutions were clustered on a small surface patch. This suggests that this domain may be involved in an interaction with the virus.
Dexamethasone and IL‐10 stimulate glucocorticoid‐induced leucine zipper synthesis by human mast cells
Authors: Godot V. , Garcia G. , Capel F. , Arock M. , Durand‐Gasselin I. , Asselin‐Labat M. L. , Emilie D. , Humbert M.
Published: June 2006

Background:  Glucocorticoids (GCs) decrease tissue mast cell (MC) number and prevent their activation via their high‐affinity IgE receptor. Glucocorticoid‐induced leucine zipper (GILZ) is one of the GC‐induced genes, which inhibits the functions of the transcriptional activators AP‐1 and NF‐κB. GILZ appears to be a critical actor in the anti‐inflammatory and immunosuppressive effects of GCs in human T lymphocytes, macrophages and dendritic cells.

Aims of the study:  We investigated whether GILZ was produced by human MCs and whether GILZ synthesis was stimulated by GCs. We also investigated whether GILZ production was modulated by (i) IL‐10, because of its common immunosuppressive properties with GCs, (ii) histamine because of its pro‐inflammatory properties and (iii) IL‐4 and IL‐5 because of their ability to favour MC survival and proliferation with SCF.

Methods:  The human MC lines HMC‐1 5C6 and LAD‐2, and cord blood‐derived MCs (CB‐MCs) were cultured alone or in the presence of GCs, IL‐10, histamine, IL‐4 or IL‐5. The expression of GILZ was evaluated by using RT‐PCR, Western blotting or immunocytochemistry.

Results:  We found that human MC lines and CB‐MCs constitutively produce GILZ. We also show that GCs and IL‐10 stimulate GILZ production by human MCs. Our present results indicate that histamine, IL‐4 and IL‐5 alone or in combination with SCF do not downregulate GILZ production by MCs.

Conclusions:  These results show that GCs and IL‐10 stimulate GILZ production by human MCs. As GILZ mediates anti‐inflammatory effects of GCs in immune cells, we speculate that GILZ could account for the deactivation of MCs by GCs and IL‐10.
Randomized double‐blind controlled study with sublingual carbamylated allergoid immunotherapy in mild rhinitis due to mites
Authors: Passalacqua G. , Pasquali M. , Ariano R. , Lombardi C. , Giardini A. , Baiardini I. , Majani G. , Falagiani P. , Bruno M. , Canonica G. W.
Published: June 2006

Background:  The clinical efficacy of sublingual immunotherapy (SLIT) in mite allergy and in mild disease is still a matter of debate, thus we performed a long‐term clinical trial.

Methods:  The study was randomized, double‐blind and placebo‐controlled. After a 1‐year assessment, 68 patients with mild rhinitis with/without asthma due to mites were randomized to drugs + placebo or drugs + SLIT for 2 years. Sublingual immunotherapy was given as soluble tablets of monomeric carbamylated allergoid. Clinical scores for asthma and rhinitis (0, absent to 3, severe) and drug consumption were assessed by diary card in the period November–February. Quality of life was assessed before and after each observation period and pharmaco‐economy data were evaluated as well.

Results:  Fifty‐six patients completed the study. The rate of dropouts was similar in the two groups. No relevant side effect was reported. There was a significant reduction of total clinical scores (P < 0.05) in the active group vs placebo at the first year, but not at the second whereas nasal obstruction significantly improved in both years (P < 0.05). The reduction of drug intake score was significant only at the first year. No change was observed concerning most of the Short Form‐36 items, because at baseline all patients displayed a normal profile. A significant change in SLIT group was seen for the item ‘change in health status’. The need for extra visits was significantly lower in the active group (25%vs 43%).

Conclusions:  Sublingual immunotherapy was clinically effective and safe in mite‐induced mild disease.
Localization of Oestrogen Receptors Within Various Bovine Ovarian Cell Types at Different Stages of the Oestrous Cycle
Authors: D'Haeseleer M. , Cornillie P. , Simoens P. , Van Den Broeck W.
Published: June 2006

In the present study oestrogen receptor α(ERα) and oestrogen receptor β (ERβ) mRNA were localized in various ovarian cell types of 23 cows at different stages of the oestrous cycle. ERα was detected by immunohistochemistry and the localization of ERβ mRNA was examined using in situ hybridization. The immunostaining of ERα was low in the ovarian follicles, tunica albuginea and surface epithelium, but high in cells of the deep stroma and superficial stroma, which indicates a functional role of ERα in the cells surrounding the follicles. In contrast, ERβ mRNA scores were low to moderate in primordial and primary follicles, and increased with the development of the follicle. ERβ mRNA scores were higher in cystic follicles than in obliterative follicles. In the corpora lutea and corpora albicantia the scores for ERβ mRNA were moderate. Furthermore, in the corpora lutea, ERβ mRNA levels showed cyclic variations and were low during early dioestrus. The correlation between plasma progesterone levels and the score for ER was low and negative in all ovarian cell types. This study demonstrates the predominant role of ERβ over ERα in bovine ovarian structures. Furthermore, the colocalization of both ERβ mRNA and ERα in most cell types suggests possible interactions between both ER subtypes.
Arterial Supply of the Superior Cervical Ganglion in the Guinea‐Pig (Cavia porcellus)
Authors: Kabak M. , Gültiken M. E.
Published: June 2006

The vascularization of the cranial cervical ganglion [superior cervical ganglion (SCG)] of 10 adult guinea‐pigs (Cavia porcellus) was investigated by latex injection and dissection techniques. Compared with other species, there were differences in the arterial supply of SCG and in the number of branches originating from these vessels. The SCG received arterial blood from branches of the ascending pharyngeal and internal carotid arteries. In addition, it was demonstrated that the superior thyroid and occipital arteries contribute rarely to the vascularization of the SCG.
NEWS‐GENERATED DEPENDENCE AND OPTIMAL PORTFOLIOS FOR n STOCKS IN A MARKET OF BARNDORFF‐NIELSEN AND SHEPHARD TYPE
Authors: Lindberg Carl
Published: June 2006

We consider Merton's portfolio optimization problem in a Black and Scholes market with non‐Gaussian stochastic volatility of Ornstein–Uhlenbeck type. The investor can trade in n stocks and a risk‐free bond. We assume that the dependence between stocks lies in that they partly share the Ornstein–Uhlenbeck processes of the volatility. We refer to these as news processes, and interpret this as that dependence between stocks lies solely in their reactions to the same news. The model is primarily intended for assets that are dependent, but not too dependent, such as stocks from different branches of industry. We show that this dependence generates covariance, and give statistical methods for both the fitting and verification of the model to data. Using dynamic programming, we derive and verify explicit trading strategies and Feynman–Kac representations of the value function for power utility.
The Incidence and Effect of Job Training among Japanese Women
Authors: KAWAGUCHI DAIJI
Published: June 2006

Using panel data of Japanese women, this paper analyzes who participates in firm‐initiated training programs and the effect of this participation on wage level and wage growth. The analysis found that workers with stronger educational backgrounds are more likely to participate in firm‐initiated training activities. Training participation and wage are positively correlated. Even after controlling for endogenous selection into training participation by a first‐difference estimation, current training participation significantly explains current wage growth.
Genetic variability and differentiation in red deer (Cervus elaphus) from Scotland and England
Authors: Hmwe S. S. , Zachos F. E. , Sale J. B. , Rose H. R. , Hartl G. B.
Published: June 2006

Samples from 69 British red deer Cervus elaphus scoticus from seven populations in Scotland and England were analysed with respect to variability within and differentiation among stocks using 11 polymorphic microsatellite loci and 439 bp of the mitochondrial control region. The results clearly showed the effects of anthropogenic factors on British red deer. On the whole, variability values were within the species' reported range. The island population of Islay, Scotland, however, while showing average microsatellite variability, exhibited no mitochondrial variation at all. One microsatellite locus was monomorphic in three Scottish populations (Islay, Dunachton and Achnacarry). Overall and pairwise FST values indicate considerable differentiation among the populations studied, but Dunachton and Achnacarry, two adjacent populations free from recorded introductions, showed only a little differentiation and were paired in trees based on genetic distances. In terms of variability, no statistically significant differences were observed between island and mainland populations and the overall test of isolation by distance was negative. Possible reasons for the genetic patterns observed, such as differences in human impact on the populations, are discussed.
Impact of live trapping on the stress response of the meadow vole (Microtus pennsylvanicus)
Authors: Fletcher Q. E. , Boonstra R.
Published: June 2006

In physiological research on natural populations, it is essential to understand the impact of capture‐induced stress because of its numerous effects on many physiological processes. Our objective was to determine the extent to which the stress levels of meadow voles Microtus pennsylvanicus were affected by short‐term responses to live trapping and how these were influenced by the amount of time spent in live traps. Baseline levels were obtained from a snap‐trapped sample and stress levels were determined from voles that had spent variable amounts of time in live traps (up to 16.5 h). Stress levels were inferred from corticosterone and glucose concentrations and haematocrit levels. In the live‐trapped sample, corticosterone concentrations reflect only the stress of trap confinement whereas glucose concentrations and haematocrit reflect both the effects of trap confinement and handling. Live trapping caused corticosterone concentrations to increase by 108% (from 390.3 to 810.6 ng mL−1), glucose concentrations to increase by 58% (from 55.4 to 87.4 mg dL−1) and haematocrit levels to increase by 10% (from 49 to 54%) from baseline levels. The length of time a vole spent in a live trap did not affect corticosterone and glucose concentrations; however, haematocrit levels increased slightly over time (0.21% h−1). We conclude that live trapping induced a stress response in voles, but that longer times in traps did not increase the stress levels.
Differentiating hair samples of the European mink (Mustela lutreola), the American mink (Mustela vison) and the European polecat (Mustela putorius) using light microscopy
Authors: González‐Esteban J. , Villate I. , Irizar I.
Published: June 2006

The European mink Mustela lutreola is a threatened species that is being monitored throughout its range, and innocuous methods of detection are needed as an alternative to live trapping, which may result in fatalities. A method is described for the identification of European mink hair by light microscopy, and its differentiation, on the basis of cuticular and medullary patterns of guard hairs, from hairs of similar mustelids, the introduced American mink Mustela vison and the European polecat Mustela putorius. When used in conjunction with hair trapping of living animals, this could prove to be the ideal way of conducting monitoring programmes on the European mink.
Craniomandibular joint in South American burrowing rodents (Ctenomyidae): adaptations and constraints related to a specialized mandibular position in digging
Authors: Verzi D. H. , Olivares A. I.
Published: June 2006

A quali‐quantitative morphofunctional analysis of the craniomandibular joint in subterranean rodents of the family Ctenomyidae showed that specializations of this joint are coupled with adaptations to digging. The presence of a postglenoid articular region in the skull ofEucelophorusandCtenomysimplies a new position of the mandible in digging, different from those involved in gnawing and chewing. In this third position of the mandible, the mandibular joint is stabilized when the deeply inserted incisors attack the soil or an obstacle, preventing dislocation. The proposed new mandibular function imposes a mechanical constraint on size and shape of the auditory bullae in tooth‐digger ctenomyids, because inflated bullae preclude a satisfactory opening of the mandible when it articulates in the postglenoid region. The configuration of the craniomandibular joint and other specializations for digging ofEucelophorusare unique among all South American rodents. The presence of non‐homologous, and even more specialized, postglenoid cavities in burrowing rodents of other continents suggests a common requirement for stabilizing the mandibular joint when strong forces with incisors are developed. The less specialized postglenoid region ofEucelophorusandCtenomys, with respect to that of other rodent clades, may be related to the more recent differentiation of ctenomyids.
Perceived parental rearing of bipolar offspring
Authors: Reichart C. G. , Van Der Ende J. , Hillegers M. H. J. , Wals M. , Bongers I. L. , Nolen W. A. , Ormel J. , Verhulst F. C.
Published: June 2006

Objective:  To explore the impact of growing up with a parent with a bipolar disorder. First, we compared parental rearing behavior perceived by young adult offspring of bipolar parents with parental rearing behavior perceived by same aged young adults from the general population. Secondly, we examined the associations between perceived parental rearing behavior and parental psychopathology and psychopathology in offspring.

Method:  Subjects were 129 offspring of 80 bipolar parents and their spouses and 1122 young adults from the general population. In offspring the Structured Clinical Interview for DSM‐IV was used to assess DSM‐IV diagnoses and the EMBU was used to assess perceived parental rearing in both groups.

Results:  In general, offspring growing up in a family with a bipolar parent perceived their mothers as less rejecting, more emotionally warm and less overprotecting and their fathers as less emotionally warm and less overprotecting compared with young adults from the general population. Perceived rejection was related to psychopathology in offspring.

Conclusion:  Overall, parental rearing in families with a parent with a bipolar disorder is not more dysfunctional, as perceived by their offspring, than in families from the general population. Offspring with a bipolar disorder perceive their parents as more rejecting.
Intensive group cognitive treatment and individual cognitive therapy vs. treatment as usual in social phobia: a randomized controlled trial
Authors: Mörtberg E. , Clark D. M. , Sundin Ö. , Åberg Wistedt A.
Published: June 2006

Objective:  To compare the effects of an intensive group cognitive treatment (IGCT) to individual cognitive therapy (ICT) and treatment as usual (TAU) in social phobia (DSM‐IV).

Method:  Hundred patients were randomized to: IGCT involving 16 group sessions spread over three weeks; ICT involving 16 shorter weekly sessions in 4 months and; TAU involving an indicated selective serotonin reuptake inhibitor (SSRI) with therapy sessions as required for 1 year. The main outcome measure was a Social Phobia Composite that combined several standardized self‐report measures. Diagnostic assessment was repeated at 1‐year follow‐up.

Results:  Significant improvements were observed with all treatments. ICT was superior to IGCT and TAU, which did not differ in overall effectiveness.

Conclusion:  The study confirms and extends previously reported findings that ICT is more effective than group cognitive treatment and treatment with SSRIs. IGCT lasts only 3 weeks, and is as effective as more protracted TAU.
Parent–teacher disagreement regarding psychopathology in children: a risk factor for adverse outcome?
Authors: Ferdinand R. F. , Van Der Ende J. , Verhulst F. C.
Published: June 2006

Objective:  To investigate if parent–teacher discrepancies in reports of behavioral/emotional problems in children predict poor outcome.

Method:  A total of 1154 4‐ to 12‐year‐old children from the general population were followed up. At the first assessment, parent and teacher ratings were obtained with the Child Behavior Checklist (CBCL) and Teacher's Report Form (TRF). Fourteen years later, DSM‐IV diagnoses were assessed, and ratings of self‐reported and parent‐rated behavioral and emotional problems were obtained.

Results:  CBCL and TRF scores predicted most of the outcomes, but in general, discrepancies between CBCL and TRF scores did not. There were some exceptions. For instance, higher parental vs. teacher ratings of aggressive behaviors increased the risk of suicide attempts/self‐mutilation.

Conclusion:  Risk factors for self‐mutilating behaviors may be supplemented with parent‐reported aggressive behaviors that are not observed by the teachers. In general, whereas CBCL and TRF scale scores were useful predictors of outcome, parent–teacher discrepancies were not.
RACE, CLASS, AND THE KATRINA CRISIS
Authors: Marable Manning
Published: June 2006

The recent human tragedy in New Orleans created by Hurricane Katrina has generated an interesting and important debate about the underlying causes of black suffering and oppression. In its most simple form, the question being debated is whether race and racism were most responsible for the Katrina crisis that disrupted the lives of hundreds of thousands of African Americans, or whether class and poverty were relatively more significant in explaining this human catastrophe.
Evaluating Comparability in Computerized Adaptive Testing: Issues, Criteria and an Example
Authors: Wang Tianyou , Kolen Michael J.
Published: June 2006

When a computerized adaptive testing (CAT) version of a test co‐exists with its paper‐and‐pencil (P&P) version, it is important for scores from the CAT version to be comparable to scores from its P&P version. The CAT version may require multiple item pools for test security reasons, and CAT scores based on alternate pools also need to be comparable to each other. In this paper, we review research literature on CAT comparability issues and synthesize issues specific to these two settings. A framework of criteria for evaluating comparability was developed that contains the following three categories of criteria: validity criterion, psychometric property/reliability criterion, and statistical assumption/test administration condition criterion. Methods for evaluating comparability under these criteria as well as various algorithms for improving comparability are described and discussed. Focusing on the psychometric property/reliability criterion, an example using an item pool of ACT Assessment Mathematics items is provided to demonstrate a process for developing comparable CAT versions and for evaluating comparability. This example illustrates how simulations can be used to improve comparability at the early stages of the development of a CAT. The effects of different specifications of practical constraints, such as content balancing and item exposure rate control, and the effects of using alternate item pools are examined. One interesting finding from this study is that a large part of incomparability may be due to the change from number‐correct score‐based scoring to IRT ability estimation‐based scoring. In addition, changes in components of a CAT, such as exposure rate control, content balancing, test length, and item pool size were found to result in different levels of comparability in test scores.
Real‐Time Feedback on Rater Drift in Constructed‐Response Items: An Example From the Golden State Examination
Authors: Hoskens Machteld , Wilson Mark
Published: June 2006

In this study, patterns of variation in severities of a group of raters over time or so‐called “rater drift” was examined when raters scored an essay written under examination conditions. At the same time feedback was given to rater leaders (called “table leaders”) who then interpreted the feedback and reported to the raters. Rater severities in five successive periods were estimated using a modified linear logistic test model (LLTM, Fischer, 1973) approach. It was found that the raters did indeed drift towards the mean, but a planned comparision of the feedback with a control condition was not successful; it was believed that this was due to contamination at the table leader level. A series of models was also estimated designed to detect other types of rater effects beyond severity: a tendency to use extreme scores, and tendency to prefer certain categories. The models for these effects were found to be showing significant improvement in fit, implying that these effects were indeed present, although they were difficult to detect in relatively short time periods.
Effects of Scale Transformation and Test‐Termination Rule on the Precision of Ability Estimation in Computerized Adaptive Testing
Authors: Yi Qing , Wang Tianyou , Ban Jae‐Chun
Published: June 2006

Error indices (bias, standard error of estimation, and root mean squared error) obtained on different measurement scales under different test‐termination rules in computerized adaptive testing (CAT) were examined. Four ability estimation methods (maximum likelihood estimation, weighted likelihood estimation, expected a posterior, and maximum a posterior), three measurement scales (θ, number‐correct score, and ACT score), and three test‐termination rules (fixed length, fixed standard error, and target information) were studied for a real and a generated item pool. The findings indicated that the amount and direction of bias, standard error of estimation, and root mean squared error obtained under different ability estimation methods were influenced both by scale transformations and by test‐termination rules in a CAT environment. The implications of these effects for testing programs are discussed.
Statistical Properties of the K‐Index for Detecting Answer Copying
Authors: Sotaridona Leonardo S. , Meijer Rob R.
Published: June 2006

We investigated the statistical properties of the K‐index (Holland, 1996) that can be used to detect copying behavior on a test. A simulation study was conducted to investigate the applicability of the K‐index for small, medium, and large datasets. Furthermore, the Type I error rate and the detection rate of this index were compared with the copying index, ω (Wollack, 1997). Several approximations were used to calculate the K‐index. Results showed that all approximations were able to hold the Type I error rates below the nominal level. Results further showed that using ω resulted in higher detection rates than the K‐indices for small and medium sample sizes (100 and 500 simulees).
The Influence of Several Factors on Reliability for Complex Reading Comprehension Tests
Authors: Lee Guemin
Published: June 2006

The purpose of this study was to investigate the effects of items, passages, contents, themes, and types of passages on the reliability and standard errors of measurement for complex reading comprehension tests. Seven different generalizability theory models were used in the analyses. Results indicated that generalizability coefficients estimated using multivariate models incorporating content strata and types of passages were similar in size to reliability estimates based upon a model that did not include these factors. In contrast, incorporating passages and themes within univariate generalizability theory models produced non‐negligible differences in the reliability estimates. This suggested that passages and themes be taken into account when evaluating the reliability of test scores for complex reading comprehension tests.
Item Parameter Estimation Under Conditions of Test Speededness: Application of a Mixture Rasch Model With Ordinal Constraints
Authors: Bolt Daniel M. , Cohen Allan S. , Wollack James A.
Published: June 2006

When tests are administered under fixed time constraints, test performances can be affected by speededness. Among other consequences, speededness can result in inaccurate parameter estimates in item response theory (IRT) models, especially for items located near the end of tests (Oshima, 1994). This article presents an IRT strategy for reducing contamination in item difficulty estimates due to speededness. Ordinal constraints are applied to a mixture Rasch model (Rost, 1990) so as to distinguish two latent classes of examinees: (a) a “speeded” class, comprised of examinees that had insufficient time to adequately answer end‐of‐test items, and (b) a “nonspeeded” class, comprised of examinees that had sufficient time to answer all items. The parameter estimates obtained for end‐of‐test items in the nonspeeded class are shown to more accurately approximate their difficulties when the items are administered at earlier locations on a different form of the test. A mixture model can also be used to estimate the class memberships of individual examinees. In this way, it can be determined whether membership in the speeded class is associated with other student characteristics. Results are reported for gender and ethnicity.
Effects of Practical Constraints on Item Selection Rules at the Early Stages of Computerized Adaptive Testing
Authors: Chen Shu‐Ying , Ankenman Robert D.
Published: June 2006

The purpose of this study was to compare the effects of four item selection rules—(1) Fisher information (F), (2) Fisher information with a posterior distribution (FP), (3) Kullback‐Leibler information with a posterior distribution (KP), and (4) completely randomized item selection (RN)—with respect to the precision of trait estimation and the extent of item usage at the early stages of computerized adaptive testing. The comparison of the four item selection rules was carried out under three conditions: (1) using only the item information function as the item selection criterion; (2) using both the item information function and content balancing; and (3) using the item information function, content balancing, and item exposure control. When test length was less than 10 items, FP and KP tended to outperform F at extreme trait levels in Condition 1. However, in more realistic settings, it could not be concluded that FP and KP outperformed F, especially when item exposure control was imposed. When test length was greater than 10 items, the three nonrandom item selection procedures performed similarly no matter what the condition was, while F had slightly higher item usage.
On the Reliability of Categorically Scored Examinations
Authors: Kupermintz Haggai
Published: June 2006

A decision‐theoretic approach to the question of reliability in categorically scored examinations is explored. The concepts of true scores and errors are discussed as they deviate from conventional psychometric definitions and measurement error in categorical scores is cast in terms ofmisclassifications. A reliability measure based on proportional reduction in loss (PRL) is then presented and exemplified with data from a large‐scale assessment. The link between the PRL approach and the classical conception of reliability is discussed. Some design considerations for reliability studies are also discussed.
Does it matter how the law thinks about corporate opportunities?
Authors: Kershaw David
Published: June 2006

English opportunities regulation is confused about its relationship to the concepts of ownership and property. Recent reform proposals from the Company Law Review Steering Group would have changed English law's dominant regulatory lens: the way in which it thinks about the opportunities problem, from an approach focused on conflicts of interest to one focused on the ‘ownership’ of opportunities. This ownership approach is commonly referred to as the corporate opportunities doctrine. This article argues that the proposal failed as it did not consider the interpretative possibilities generated by changing the regulatory lens. However, the proposal inadvertently makes a contribution to the debate as it directs our attention to the function and meaning of ownership concepts in the opportunities context. Property in the opportunities setting is simply a label for qualified ownership as between the director and the company. However, the article argues that by understanding references to property in terms of traditional notions of property English law and commentary has obstructed the consideration and development of a long-standing English corporate opportunities doctrine.
Claiming damages upon an anticipatory breach: why should an acceptance be necessary?
Authors: Liu Qiao
Published: June 2006

This article is an attempt to defend the English rule that an anticipatory breach does not automatically give rise to a right of action for damages unless and until it is ‘accepted’. The article first explores the major arguments for and against the rule and finds that the rule is justifiable on the ground of finality and consistency and that none of its objections are persuasive enough to overturn the rule. The article further observes that the rule must be qualified in two important respects in order to retain its rational force. However, the above rule is currently stated by the courts to the effect that an anticipatory breach is not per se a breach and is only ‘converted’ into a breach when it is ‘accepted’. It is proposed that this statement is historically unwarranted and contradicts sound logic and should thus be discarded.
Citizenship and family life in Ireland: asking the question ‘Who belongs’?
Authors: Mullally Siobhán
Published: June 2006

Citizenship laws provide us with models of membership. They define the terms on which strangers and natives belong to political communities, allocating both the benefits of membership and the brutalities of exclusion. Recent legal changes in Ireland, restricting the right to citizenship by birth and limiting the rights of migrant families, highlight the vulnerability of children in migrant families and the limits of citizenship status. Many other states have grappled in recent times with the right to citizenship by birth and the entitlements to family life that come with such a claim. In both the UK and Australia the jus soli principle has been significantly restricted. In the US, Canada and elsewhere, while the jus soli principle continues to apply, citizen children born to undocumented migrant parents are subject to de facto deportations, their right to membership of the nation-state ‘postponed’ because of the legal status of their parents. In challenges to deportation proceedings involving such children, the perspective of the child as a bearer of rights is marginalised, with disputes turning largely on the balancing of states' interests in immigration control against the residence claims made by migrant parents.
Cortex Is Driven by Weak but Synchronously Active Thalamocortical Synapses
Authors: Bruno Randy M. , Sakmann Bert
Published: June 2006

Sensory stimuli reach the brain via the thalamocortical projection, a group of axons thought to be among the most powerful in the neocortex. Surprisingly, these axons account for only ∼15% of synapses onto cortical neurons. The thalamocortical pathway might thus achieve its effectiveness via high-efficacy thalamocortical synapses or via amplification within cortical layer 4. In rat somatosensory cortex, we measured in vivo the excitatory postsynaptic potential evoked by a single synaptic connection and found that thalamocortical synapses have low efficacy. Convergent inputs, however, are both numerous and synchronous, and intracortical amplification is not required. Our results suggest a mechanism of cortical activation by which thalamic input alone can drive cortex.
Extrafollicular Activation of Lymph Node B Cells by Antigen-Bearing Dendritic Cells
Authors: Qi Hai , Egen Jackson G. , Huang Alex Y. C. , Germain Ronald N.
Published: June 2006

In contrast to naïve T cells that recognize short antigen-derived peptides displayed by specialized antigen-presenting cells, immunoglobulin receptors of B lymphocytes primarily recognize intact proteins. How and where within a lymph node such unprocessed antigens become available for naïve B cell recognition is not clear. We used two-photon intravital imaging to show that, after exiting high-endothelial venules and before entry into lymph node follicles, B cells survey locally concentrated dendritic cells. Engagement of the B cell receptor by the dendritic cell (DC)–associated antigen leads to lymphocyte calcium signaling, migration arrest, antigen acquisition, and extrafollicular accumulation. These findings suggest a possible role for antigen-specific B-DC interactions in promoting T cell–dependent antibody responses in vivo.
Element Partitioning: The Role of Melt Structure and Composition
Authors: Schmidt M. W. , Connolly J. A. D. , Günther D. , Bogaerts M.
Published: June 2006

We segregated coexisting gabbroic and granitic melts by centrifuging them at high pressures and temperatures and measured the trace element compositions of the melts by laser ablation inductively coupled plasma mass spectrometry. Our results demonstrate that the effect of melt structure contributes about one order of magnitude to crystal/melt partition coefficients. Partitioning of alkali and alkaline earth elements strongly depends on field strength: Amphoteric and lone pair electron elements partition into the polymerized granitic melt; and rare earth, transition, and high field strength elements coordinated by nonbridging oxygens partition remarkably similar into the gabbroic melt. A regular solution model predicts these effects.
Best and Brightest of His Generation
Authors: Yochelson Ellis L.
Published: June 2006

The Explorer King
. Adventure, Science, and the Great Diamond Hoax--Clarence King in the Old West.
By Robert Wilson
. Scribner, New York, 2006. 317 pp. $26, C$36. ISBN 0-743-26025-2.

King of the 40th Parallel
. Discovery in the American West.
By James G. Moore
. Stanford University Press, Stanford, CA, 2006. 411 pp. $55. ISBN 0-8047-5222-2. Paper, $21.95. ISBN 0-8047-5223-0.

The adventures and accomplishments of Clarence King---geologist, explorer, mountaineer, and first director of the U.S. Geological Survey---are the subject of two recent books.
Immunogenicity of Cytopathic and Noncytopathic Viral Vectors
Authors: Plesa Gabriela , McKenna Philip M. , Schnell Matthias J. , Eisenlohr Laurence C.
Published: June 2006

The impact of cytolytic versus noncytolytic viral infections on host responses is not well understood, due to limitations of the systems that have been used to address this issue. Using paired cytopathic and noncytopathic rabies viruses that differ by only two amino acids, we investigated several fundamental aspects of the immune response to these viral vectors. Greater cytopathic capacity translated into a greater degree of cross-priming to CD8+T cells (TCD8+) and more-robust short-term humoral and cellular responses. However, long-term responses to the two viruses were similar, suggesting that direct priming drives the bulk of the TCD8+antirabies response and that enhanced acute responses associated with greater virally mediated cellular destruction were balanced by other factors, such as prolonged antigen expression associated with noncytopathic virus. Such compensatory mechanisms may be in place to ensure comparable immunologic memories to various pathogens.
Toll-Like Receptor Adaptor Molecules Enhance DNA-Raised Adaptive Immune Responses against Influenza and Tumors through Activation of Innate Immunity
Authors: Takeshita Fumihiko , Tanaka Toshiyuki , Matsuda Tomoko , Tozuka Miyuki , Kobiyama Kouji , Saha Sukumar , Matsui Kiyohiko , Ishii Ken J. , Coban Cevayir , Akira Shizuo , Ishii Norihisa , Suzuki Koichi , Klinman Dennis M. , Okuda Kenji , Sasaki Shin
Published: June 2006

Toll-like receptors (TLRs) recognize microbial components and trigger the signaling cascade that activates the innate and adaptive immunity. TLR adaptor molecules play a central role in this cascade; thus, we hypothesized that overexpression of TLR adaptor molecules could mimic infection without any microbial components. Dual-promoter plasmids that carry an antigen and a TLR adaptor molecule such as the Toll-interleukin-1 receptor domain-containing adaptor-inducing beta interferon (TRIF) or myeloid differentiation factor 88 (MyD88) were constructed and administered to mice to determine if these molecules can act as an adjuvant. A DNA vaccine incorporated with the MyD88 genetic adjuvant enhanced antigen-specific humoral immune responses, whereas that with the TRIF genetic adjuvant enhanced cellular immune responses. Incorporating the TRIF genetic adjuvant in a DNA vaccine targeting the influenza HA antigen or the tumor-associated antigen E7 conferred superior protection. These results indicate that TLR adaptor molecules can bridge innate and adaptive immunity and potentiate the effects of DNA vaccines against virus infection and tumors.