bluuebunny/crossref_metadata_2025 huggingface dataset:
Isoflurane-induced acidosis depresses basal and PGE2-stimulated duodenal bicarbonate secretion in mice
Authors: Sjöblom Markus , Nylander Olof
Published: December 2006

When running in vivo experiments, it is imperative to keep arterial blood pressure and acid-base parameters within the normal physiological range. The aim of this investigation was to explore the consequences of anesthesia-induced acidosis on basal and PGE2-stimulated duodenal bicarbonate secretion. Mice (strain C57bl/6J) were kept anesthetized by a spontaneous inhalation of isoflurane. Mean arterial blood pressure (MAP), arterial acid-base balance, and duodenal mucosal bicarbonate secretion (DMBS) were studied. Two intra-arterial fluid support strategies were used: a standard Ringer solution and an isotonic Na2CO3 solution. Duodenal single perfusion was used, and DMBS was assessed by back titration of the effluent. PGE2 was used to stimulate DMBS. In Ringer solution-infused mice, isoflurane-induced acidosis became worse with time. The blood pH was 7.15–7.21 and the base excess was about −8 mM at the end of experiments. The continuous infusion of Na2CO3 solution completely compensated for the acidosis. The blood pH was 7.36–7.37 and base excess was about 1 mM at the end of the experiment. Basal and PGE2-stimulated DMBS were markedly greater in animals treated with Na2CO3 solution than in those treated with Ringer solution. MAP was slightly higher after Na2CO3 solution infusion than after Ringer solution infusion. We concluded that isoflurane-induced acidosis markedly depresses basal and PGE2-stimulated DMBS as well as the responsiveness to PGE2, effects prevented by a continuous infusion of Na2CO3. When performing in vivo experiments in isoflurane-anesthetized mice, it is recommended to supplement with a Na2CO3 infusion to maintain a normal acid-base balance.
Restraint stress stimulates colonic motility via central corticotropin-releasing factor and peripheral 5-HT3 receptors in conscious rats
Authors: Nakade Yukiomi , Fukuda Hiroyuki , Iwa Masahiro , Tsukamoto Kiyoshi , Yanagi Hidenori , Yamamura Takehira , Mantyh Christopher , Pappas Theodore. N. , Takahashi Toku
Published: December 2006

Although restraint stress accelerates colonic transit via a central corticotropin-releasing factor (CRF), the precise mechanism still remains unclear. We tested the hypothesis that restraint stress and central CRF stimulate colonic motility and transit via a vagal pathway and 5-HT3 receptors of the proximal colon in rats. 51Cr was injected via the catheter positioned in the proximal colon to measure colonic transit. The rats were subjected to a restraint stress for 90 min or received intracisternal injection of CRF. Ninety minutes after the administration of 51Cr, the entire colon was removed, and the geometric center (GC) was calculated. Four force transducers were sutured on the proximal, mid, and distal colon to record colonic motility. Restraint stress accelerated colonic transit (GC of 6.7 ± 0.4, n = 6) compared with nonrestraint controls (GC of 5.1 ± 0.2, n = 6). Intracisternal injection of CRF (1.0 μg) also accelerated colonic transit (GC of 7.0 ± 0.2, n = 6) compared with saline-injected group (GC of 4.6 ± 0.5, n = 6). Restraint stress-induced acceleration of colonic transit was reduced by perivagal capsaicin treatment. Intracisternal injection of CRF antagonists (10 μg astressin) abolished restraint stress-induced acceleration of colonic transit. Stimulated colonic transit and motility induced by restraint stress and CRF were significantly reduced by the intraluminal administration of 5-HT3 antagonist ondansetron (5 × 10−6 M; 1 ml) into the proximal colon. Restraint stress and intracisternal injection of CRF significantly increased the luminal content of 5-HT of the proximal colon. It is suggested that restraint stress stimulates colonic motility via central CRF and peripheral 5-HT3 receptors in conscious rats.
Deciphering the metabolic and mechanical contributions to the exercise-induced circulatory response: insights from eccentric cycling
Authors: Dufour Stéphane P. , Doutreleau Stéphane , Lonsdorfer-Wolf Evelyne , Lampert Eliane , Hirth Christine , Piquard François , Lonsdorfer Jean , Geny Bernard , Mettauer Bertrand , Richard Ruddy
Published: December 2006

Metabolic demand and muscle mechanical tension are closely coupled during exercise, making their respective drives to the circulatory response difficult to establish. This coupling being altered in eccentric cycling, we implemented an experimental design featuring eccentric vs. concentric constant-load cycling bouts to gain insights into the control of the exercise-induced circulatory response in humans. Heart rate (HR), stroke volume (SV), cardiac output (Q̇), oxygen uptake (V̇o2), and electromyographic (EMG) activity of quadriceps muscles were measured in 11 subjects during heavy concentric (heavy CON: 270 ± 13 W; V̇o2 = 3.59 ± 0.20 l/min), heavy eccentric (heavy ECC: 270 ± 13 W, V̇o2 = 1.17 ± 0.15 l/min), and light concentric (light CON: 70 ± 9 W, V̇o2 = 1.14 ± 0.12 l/min) cycle bouts. Using a reductionist approach, the circulatory responses observed between heavy CON vs. light CON (difference in V̇o2 and power output) was ascribed either to metabolic demand, as estimated from heavy CON vs. heavy ECC (similar power output, different V̇o2), or to muscle mechanical tension, as estimated from heavy ECC vs. light CON (similar V̇o2, different power output). 74% of the Q̇ response was determined by the metabolic demand, also accounting for 65% and 84% of HR and SV responses, respectively. Consequently, muscle mechanical tension determined 26%, 35%, and 16% of the Q̇, HR, and SV responses, respectively. Q̇ was significantly related to V̇o2 ( r2 = 0.83) and EMG activity ( r2 = 0.82; both P < 0.001). These results suggest that the exercise-induced circulatory response is mainly under metabolic control and support the idea that the level of muscle activation plays a role in the cardiovascular regulation during cycle exercise in humans.
Short-Term Adaptation and Temporal Processing in the Cryophilic Response ofCaenorhabditis elegans
Authors: Clark Damon A. , Gabel Christopher V. , Lee Timothy M. , Samuel Aravinthan D. T.
Published: December 2006

When navigating spatial thermal gradients, the nematode C. elegans migrates toward colder temperatures until it reaches its previous cultivation temperature, exhibiting cryophilic movement. The strategy for effecting cryophilic movement is the biased random walk: C. elegans extends (shortens) periods of forward movement that are directed down (up) spatial thermal gradients by modulating the probability of reorientation. Here, we analyze the temporal sensory processor that enables cryophilic movement by quantifying the movements of individual worms subjected to defined temperature waveforms. We show that step increases in temperature as small as 0.05°C lead to transient increases in the probability of reorientation followed by gradual adaptation to the baseline level; temperature downsteps leads to similar but inverted responses. Short-term adaptation is a general property of sensory systems, allowing organisms to maintain sensitivity to sensory variations over broad operating ranges. During cryophilic movement C. elegans also uses the temporal dynamics of its adaptive response to compute the time derivative of gradual temperature variations with exquisite sensitivity. On the basis of the time derivative, the worm determines how it is oriented in spatial thermal gradients during each period of forward movement. We show that the operating range of the cryophilic response extends to lower temperatures in ttx-3 mutants, which affects the development of the AIY interneurons. We show that the temporal sensory processor for the cryophilic response is affected by mutation in the EAT-4 glutamate vesicular transporter. Regulating the operating range of the cryophilic response and executing the cryophilic response may have separate neural mechanisms.
Method for Counting Motor Units in Mice and Validation Using a Mathematical Model
Authors: Major Lora A. , Hegedus Janka , Weber Douglas J. , Gordon Tessa , Jones Kelvin E.
Published: December 2006

Weakness and atrophy are clinical signs that accompany muscle denervation resulting from motor neuron disease, peripheral neuropathies, and injury. Advances in our understanding of the genetics and molecular biology of these disorders have led to the development of therapeutic alternatives designed to slow denervation and promote reinnervation. Preclinical in vitro research gave rise to the need of a method for measuring the effects in animal models. Our goal was to develop an efficient method to determine the number of motor neurons making functional connections to muscle in a transgenic mouse model of amyotrophic lateral sclerosis (ALS). We developed a novel protocol for motor unit number estimation (MUNE) using incremental stimulation. The method involves analysis of twitch waveforms using a new software program, ITS-MUNE, designed for interactive calculation of motor unit number. The method was validated by testing simulated twitch data from a mathematical model of the neuromuscular system. Computer simulations followed the same stimulus-response protocol and produced waveform data that were indistinguishable from experiments. We show that our MUNE protocol is valid, with high precision and small bias across a wide range of motor unit numbers. The method is especially useful for large muscle groups where MUNE could not be done using manual methods. The results are reproducible across naïve and expert analysts, making it suitable for easy implementation. The ITS-MUNE analysis method has the potential to quantitatively measure the progression of motor neuron diseases and therefore the efficacy of treatments designed to alleviate pathologic processes of muscle denervation.
Calculating Event-Triggered Average Synaptic Conductances From the Membrane Potential
Authors: Pospischil Martin , Piwkowska Zuzanna , Rudolph Michelle , Bal Thierry , Destexhe Alain
Published: December 2006

The optimal patterns of synaptic conductances for spike generation in central neurons is a subject of considerable interest. Ideally such conductance time courses should be extracted from membrane potential ( Vm) activity, but this is difficult because the nonlinear contribution of conductances to the Vm renders their estimation from the membrane equation extremely sensitive. We outline here a solution to this problem based on a discretization of the time axis. This procedure can extract the time course of excitatory and inhibitory conductances solely from the analysis of Vm activity. We test this method by calculating spike-triggered averages of synaptic conductances using numerical simulations of the integrate-and-fire model subject to colored conductance noise. The procedure was also tested successfully in biological cortical neurons using conductance noise injected with dynamic clamp. This method should allow the extraction of synaptic conductances from Vm recordings in vivo.
Neural Correlates of Disparity-Defined Shape Discrimination in the Human Brain
Authors: Chandrasekaran Chandramouli , Canon Victor , Dahmen Johannes C. , Kourtzi Zoe , Welchman Andrew E.
Published: December 2006

Binocular disparity, the slight differences between the images registered by our two eyes, provides an important cue when estimating the three-dimensional (3D) structure of the complex environment we inhabit. Sensitivity to binocular disparity is evident at multiple levels of the visual hierarchy in the primate brain, from early visual cortex to parietal and temporal areas. However, the relationship between activity in these areas and key perceptual functions that exploit disparity information for 3D shape perception remains an important open question. Here we investigate the link between human cortical activity and the perception of disparity-defined shape, measuring fMRI responses concurrently with psychophysical shape judgments. We parametrically degraded the coherence of shapes by shuffling the spatial position of dots whose disparity defined the 3D structure and investigated the effect of this stimulus manipulation on both cortical activity and shape discrimination. We report significant relationships between shape coherence and fMRI response in both dorsal (V3, hMT+/V5) and ventral (LOC) visual areas that correspond to the observers' discrimination performance. In contrast to previous suggestions of a dichotomy of disparity-related processes in the ventral and dorsal streams, these findings are consistent with proposed interactions between these pathways that may mediate a continuum of processes important in perceiving 3D shape from coarse contour segmentation to fine curvature estimation.
Opposing Inward and Outward Conductances Regulate Rebound Discharges in Olfactory Mitral Cells
Authors: Balu Ramani , Strowbridge Ben W.
Published: December 2006

The olfactory bulb, a second-order sensory brain region, relays afferent input from olfactory receptor neurons to piriform cortex and other higher brain centers. Although large inhibitory postsynaptic potentials (IPSPs) are evident in in vivo intracellular recordings from mitral cells, the functional significance of these synaptic responses has not been defined. In many brain regions, IPSPs can function to either inhibit spiking by transiently suppressing activity or can evoke spiking directly by triggering rebound discharges. We used whole cell patch-clamp recordings from mitral cells in olfactory bulb slices to investigate the mechanisms by which IPSPs regulate mitral cell spike discharges. Mitral cells have unusual intrinsic membrane properties that support rebound spike generation in response to small-amplitude (3–5 mV) but not large-amplitude hyperpolarizing current injections or IPSPs. Rebound spiking occurring in mitral cells was dependent on recovery of subthreshold Na currents, and could be blocked by tetrodotoxin (TTX, 1 μM) or the subthreshold Na channel blocker riluzole (10 μM). Surprisingly, larger-amplitude hyperpolarizing stimuli impeded spike generation by recruiting a transient outward IA-like current that was sensitive to high concentrations of 4-aminopyridine and Ba. The interplay of voltage-gated subthreshold Na channels and transient outward current produces a narrow range of IPSP amplitudes that generates rebound spikes. We also found that subthreshold Na channels boost subthreshold excitatory stimuli to produce membrane voltages where granule-cell-mediated IPSPs can produce rebound spikes. These results demonstrate how the intrinsic membrane properties of mitral cells enable inhibitory inputs to bidirectionally control spike output from the olfactory bulb.
Disrupted Neuronal Activity Rhythms in the Suprachiasmatic Nuclei of Vasoactive Intestinal Polypeptide-Deficient Mice
Authors: Brown T. M. , Colwell C. S. , Waschek J. A. , Piggins H. D.
Published: December 2006

Vasoactive intestinal polypeptide (VIP), acting via the VPAC2receptor, is a key signaling pathway in the suprachiasmatic nuclei (SCN), the master clock controlling daily rhythms in mammals. Most mice lacking functional VPAC2receptors are unable to sustain behavioral rhythms and lack detectable SCN electrical rhythms in vitro. Adult mice that do not produce VIP (VIP/PHI−/−) exhibit less severe alterations in wheel-running rhythms, but the effects of this deficiency on the amplitude, phasing, or periodicity of their SCN cellular rhythms are unknown. To investigate this, we used suction electrodes to extracellularly record multiple- and single-unit electrical activity in SCN brain slices from mice with varying degrees of VIP deficiency, ranging from wild-type (VIP/PHI+/+) to heterozygous (VIP/PHI+/−) and VIP/PHI−/−animals. We found decreasing proportions of rhythmic cells in SCN slices from VIP/PHI+/+(∼91%, n = 23) through VIP/PHI-/+(∼71%, n = 28) to VIP/PHI−/−mice (62%; n = 37) and a parallel trend toward decreasing amplitude in the remaining rhythmic cells. SCN neurons from VIP/PHI−/−mice exhibited a broad range in the period and phasing of electrical rhythms, concordant with the known alterations in their behavioral rhythms. Further, treatment of VIP/PHI−/−slices with a VPAC2receptor antagonist significantly reduced the proportion of oscillating neurons, suggesting that VPAC2receptors still become activated in the SCN of these mice. The results establish that VIP is important for appropriate periodicity and phasing of SCN neuronal rhythms and suggest that residual VPAC2receptor signaling promotes rhythmicity in adult VIP/PHI−/−mice.
Regulation of G Protein and Mitogen-Activated Protein Kinase Signaling by Ubiquitination
Authors: Wang Yuqi , Dohlman Henrik G.
Published: December 2006

Guanine nucleotide binding proteins (G proteins) and mitogen-activated protein kinases are highly conserved signaling molecules engaged in a wide variety of cellular processes. The strength and duration of signaling mediated by G proteins and mitogen-activated protein kinases are well known to be regulated via phosphorylation of pathway components. Over the past few years, it has become evident that many of the same signaling proteins also undergo ubiquitination, a posttranslational modification that typically leads to protein degradation. Consequently the strength and duration of signaling can also be modulated by regulating the abundance of signaling proteins. This article describes G protein– and mitogen-activated protein kinase–mediated signaling pathways that are known to be regulated by ubiquitination. The focus is on studies performed in the budding yeast
Saccharomyces cerevisiae
, as many principles governing this new regulatory mechanism were initially discovered in this model organism. Similar mechanisms uncovered in other model systems are also briefly discussed to illustrate the importance and universality of signaling regulation by ubiquitination.
Activation of Platelet Function Through G Protein–Coupled Receptors
Authors: Offermanns Stefan
Published: December 2006

Because of their ability to become rapidly activated at places of vascular injury, platelets are important players in primary hemostasis as well as in arterial thrombosis. In addition, they are also involved in chronic pathological processes including the atherosclerotic remodeling of the vascular system. Although primary adhesion of platelets to the vessel wall is largely independent of G protein–mediated signaling, the subsequent recruitment of additional platelets into a growing platelet thrombus requires mediators such as ADP, thromboxane A
2
, or thrombin, which act through G protein–coupled receptors. Platelet activation via G protein–coupled receptors involves 3 major G protein–mediated signaling pathways that are initiated by the activation of the G proteins G
q
, G
13
, and G
i
. This review summarizes recent progress in understanding the mechanisms underlying platelet activation and thrombus extension via G protein–mediated signaling pathways.
Heart Failure and Protein Quality Control
Authors: Wang Xuejun , Robbins Jeffrey
Published: December 2006

The heart is constantly under mechanical, metabolic, and thermal stress, even at baseline physiological conditions, and cardiac stress may increase as a result of environmental or intrinsic pathological insults. Cardiomyocytes are continuously challenged to efficiently and properly fold nascent polypeptides, traffic them to their appropriate cellular locations, and keep them from denaturing in the face of normal and pathological stimuli. Because deployment of misfolded or unfolded proteins can be disastrous, cells, in general, and cardiomyocytes, in particular, have developed a multilayered protein quality control system for maintaining proper protein conformation and for reorganizing and removing misfolded or aggregated polypeptides. Here, we examine recent data pointing to the importance of protein quality control in cardiac homeostasis and disease.
God's Fullness in Bodily Form: Christ and Church in Colossians
Authors: Henderson Suzanne Watts
Published: December 2006

This study explores the language of ‘fullness’ found in Colossians 2:9–10, where the Pauline writer suggests that Christ's fullness now manifests itself in those who are ‘in him’. As Christ's body, the church has been filled with the power of God and presses toward the full expression of God's renewal of ‘all things’.
Position Statement
Authors: Simner Marvin L.
Published: December 2006

Each spring teachers throughout Canada are required to administer a series of provinciallymandated tests to the students in their classes. Approximately six months later the results are made available to the public. It is now common practice for the press the report the results, to rank the schools according to the results, and to invite the public to engage in a school-by-school comparison of the rankings. It is also common practice for the press, in commenting on the poor performances displayed by certain schools, to place the blame for these performances largely, if not solely, on the schools themselves.

Our concern over this practice is with the failure on the part of the press to acknowledge the many other factors aside from schooling that are known to influence test performance. These include, but are not limited to, family stability, parental involvement and expectations for student success in school, early and ongoing home stimulation, and student motivation, student absenteeism, as well as student capacity for learning. Because students are not randomly assigned to schools and because schools have little or no control over the majority of these factors, any attempt to place the blame for poor test performance on the schools alone without giving proper consideration to each of these other factors is problematic at best and misleading at worst. Hence, by taking such a narrow position when dealing with an issue as complex as the cause of students' test performances, we believe the public is being misinformed on a matter that is extremely important to the operation of schools and therefore to the education and well being of children.

Our greatest concern, however, is over the possibility that this singular emphasis on the schools as the cause of students' test performances could generate considerable harm by placing unwarranted pressure on teachers, administrators, and ultimately on the students themselves to increase test scores or risk losing status within the community. Indeed, there is growing evidence that such harm is already occurring in the United States from similar comments in the US press concerning the poor performance of certain schools on the state-mandated tests. With the hope of preventing similar situations from occurring in Canada, and in line with the view expressed by the Ontario Education Quality and Accountability Office, which is responsible for the development and scoring of the Ontario exams, it is our position that it is improper for the press to invite the public to compare schools based solely on the outcome of the mandated test results. We also recommend that in any future articles that deal with the results, in order to avoid misleading the public, the press should ensure that the public is fully informed of the various factors, in addition to schooling, that are likely to account for differences that may exist among schools.
Cross-sectional and Longitudinal Psychosocial Correlates of Adolescent Life Satisfaction Reports
Authors: Huebner E. Scott , Funk Benjamin A. , Gilman Rich
Published: December 2006

The internal consistency, one-year stability, and cross-sectional and longitudinal correlates of a global life satisfaction measure, the Students' Life Satisfaction Scale (SLSS: Huebner, 1991a), were investigated. The SLSS and Behavior Assessment System for Children-Self-Report-Adolescent Form (BASC: Reynolds & Kamphaus, 1992) were both administered to a sample of high school students on two occasions separated by one year. Alpha coefficients indicated adequate internal consistency for research purposes. The one-year test-retest coefficient suggested moderate stability of adolescent reports. Cross-sectional and longitudinal patterns of correlations between the SLSS and BASC Adaptive and Clinical measures were consistent with expectations for the most part and suggested that SLSS scores have meaningful relations with important mental health variables. It was concluded that greater attention should be devoted to the study of life satisfaction in children and youth.
Concurrent Validity of the Wechsler Abbreviated Scale of Intelligence (WASI) with a Sample of Canadian Children
Authors: Saklofske Donald H. , Caravan Giti , Schwartz Colin
Published: December 2006

The Wechsler Abbreviated Scale of Intelligence (WASI; Wechsler, 1999) subtest and IQ scores were correlated with the Canadian Achievement Tests/2 and the Canadian Test of Cognitive Skills using 64 grade four Canadian children. The pattern of correlations offer preliminary support for the use of the WASI in assessing the ability levels of Canadian school children.
Validity and Reliability of the Draw A Person: Screening Procedure for Emotional Disturbance with Adolescent Students
Authors: Wrightson Linda , Saklofske Donald H.
Published: December 2006

The Draw A Person: Screening Procedure for Emotional Disturbance (DAP:SPED; Naglieri, 1991) was developed to provide a quick screening measure for the identification of children and adolescents who may have emotional disorders. The present study examined the test-retest reliability and validity of the DAP:SPED with three groups of adolescents: mainstream students, alternate education students, and students manifesting behavior problems. Significant score differences were found only between the regular and the alternate and behavior class students on the DAP:SPED scores. In contrast, significant score differences between all three groups were found on the Devereux Behavior Rating Scale and the Child Behavior Checklist. Test-retest reliability over 23-27 weeks was relatively low. Results of the present study suggest that the DAP:SPED may have limited utility in the identification of adolescents with behavior disorders.
Social Exile: The Cycle of Peer Victmization for Boys with ADHD
Authors: Shea Barbara , Wiener Judith
Published: December 2006

The goal of this study was to gain insight into the experience of chronic peer victimization for boys with ADHD. Using an interview guide, four boys with diagnosed ADHD, aged 11 to 13 years, their parents, and their teachers were interviewed about the children's bullying experiences. Qualitative analysis of the interview data revealed that social exclusion was the most salient form of peer harassment, that the boys were perceived as being different from other children, socially isolated, and psychologically and emotionally beaten down. The pervasiveness of social exclusion and isolation led to the development of the core category of Social Exile. For these children, social skills deficits, emotional volatility, immaturity, and a lack of insight characterized being different. Being different was perceived as causing much of the ictimnization perpetrated upon the boys, which subsequently led to severe psychological and emotional distress.
An Evaluation of the Structured Success Program: From the Students' Point of View
Authors: Da Silva Trudy A.
Published: December 2006

This study examined a special education program from the perspective of students with einotional/behavioral disturbances (E/BD). Participants in the study were enrolled in a Structured Success Program selected from 5 schools in the Saskatoon area. The subjects (N = 17) were male and ranged in age from 11 to 14 years. To examine students' perceptions of their classroom enNironment and self-concept, subjects were administered the Classroom Environment Scale (CES) and the Multidimensional Self-Concept Scale (MSCS). Semi-structured interviews were also conducted to gain insight into the general experiences of students in the program. The mean scores for the current sample on the subscales of the CES and the MSCS were compared to the normative sample. A correlational analysis between the subscales on the CES and the subscales of the MSCS was also performed. Results indicated that the two groups differed significantly on five of the nine subscales on the CES. Self-report ratings on the MSCS between the two groups revealed no differences. Findings from the interview suggested the emergence of two themes among the participants-a general sense of anger and resentment, and social impairments.
Review of Theoretical and Applied lssues in Written Language Expression
Authors: Fitze Kim
Published: December 2006

Being able to express oneself through writing is important for demonstrating learning and knowledge. Unfortunately, recent studies reveal an increasing number of students at all levels of education who have difficulty communicating their know ledge, ideas, and beliefs through written language. Various researchers have revealed that planning is one of the main processes involved in written expression. It has been demonstrated that effective writers spend a good deal of time planning their work and that. improved composition rests upon improved planning. This article reviews current theoretical models and research in the field of written expression. It addresses the complex nature of writing and. suggests the need for an. integrative approach to the instruction. and assessment of written expression.
The Role of Validity in Psychological Measurement for School Psychology Applications
Authors: Beran Tanya N.
Published: December 2006

The purpose of this paper is to explicate the role of validity in psychological measurement for applications in school psychology. The emergence of psychologicaltesting and validity is briefly renriewed. An essential quality of measurement, namely validity, is subsequently examined with a focus on delimitations and limitations of tests. The statistical determination of various types of validity is also presented to assist school psychologists in determining the precision of individualtest scores and degree of validity. In addition, factors that reduce validity are considered. The paper concludes with an emphasis on integrating data fromn various sources to substantiate interpretations of test results.
Predicting the Occurrence of Stalking in Relationships Characterized by Domestic Violence
Authors: Melton Heather C.
Published: December 2006

A high correlation has been found between domestic violence and stalking. However, very few studies have examined what factors predict the occurrence of stalking in relationships characterized by domestic violence. Using in-depth interviews with victims of domestic violence whose cases have gone through the criminal justice system, this article explores this issue. It was found that experiences of stalking by their abusers were very prevalent in this group of domestic violence victims. In terms of predicting stalking, domestic violence victims who were not in a relationship with their abuser, whose abusers had an alcohol or drug problem, who experienced more controlling behaviors by their abusers, and who had experienced prior stalking by their abusers were at the greatest risk of experiencing more severe stalking. Implications for intervention are discussed.
Marginalization Myths and the Complexity of “Men”
Authors: Gosine Andil
Published: December 2006

This article considers conversations about men and masculinity being pursued in the English-speaking Caribbean and the Republic of Ireland. The author engages structural-materialist analysis to evaluate claims circulating in both contexts that suggest men are being marginalized because of their sex-gender and employs cultural analysis to examine the representation of men’s experiences in dominant discursive frameworks. Through reference to two programs that have attempted responses that address the alleged “crisis of masculinity”—Ireland’s Exploring Masculinities program and Saint Lucia’s Men’s Resource Centre in Saint Lucia—the author identifies some of the implications of a limited analysis and also discusses some of the ways in which these programs provide potential opportunities for a more critical conversation about the situation of men and the production of masculinities.
Consequences to Federal Programs When the Logic-Modeling Process Is Not Followed With Fidelity
Authors: Renger Ralph
Published: December 2006

The Office of Management and Budget has recommended the termination of numerous federal programs, citing a lack of program results as the primary reason for this decision. In response to this recommendation, several federal agencies have turned to logic modeling to demonstrate that programs are on the path to results accountability. However, approaches to logic modeling in some agencies have not followed the strategies that evaluators recommend as necessary to lead to a high quality logic model. Models of poor quality are unlikely to contribute to improved program accountability or better program results. In this article, the author assesses the quality of the logic-modeling approach taken by one agency to illustrate how a flawed approach to logic modeling may lead to incorrect conclusions about programs and about the benefits of logic models. As a result of this analysis, the author questions the conditions under which capacity building should be considered and whether the field of evaluation needs to be more judicious when mainstreaming methodologies.
The Meaning of Effectiveness in Assessing Community Initiatives
Authors: Schweigert Francis J.
Published: December 2006

In the present climate of public accountability, there is increasing demand to show “what works” and what return is gained for the public from investments to improve communities. This increasing demand for accountability is being met with growing confidence in the field of philanthropy during the past 10 years that the impact or effectiveness of community initiatives can be measured. A review of recent evaluation reports and literature reveals three different meanings of effectiveness in use: increased understanding, accountability, and demonstrated causal linkages. Drawing on a general analysis of the concepts of accountability, effectiveness, and causality, each meaning of effectiveness is examined in light of its implications for evaluation design. The article closes with a guiding schema for organizations planning evaluations to help determine which kind of effectiveness is important in light of organizational values and aims.
Investigating the Potential of Using Social Network Analysis in Educational Evaluation
Authors: Penuel William R. , Sussex Willow , Korbak Christine , Hoadley Christopher
Published: December 2006

This article describes results of a study investigating the potential of using social network analysis to evaluate programs that aim at improving schools by fostering greater collaboration between teachers. The goal of this method is to use data about teacher collaboration within schools to map the distribution of expertise and resources needed to enact reforms. Such maps are of great potential value to school leaders, who are responsible for instructional leadership in schools, but they also include information that could bring harm to individuals and school communities. In this article, the authors describe interview findings about concerns educators have with collecting and sharing social network data. A chief finding is that although the majority of teachers consider collecting social network data to be problematic but feasible, some teachers report concerns about privacy and the effect on their school's goals to foster community if the data are shared with their schools.
Interaccion de fosdrin con montmorillonita
Authors: Sanchez Martin M. J. , Sanchez Camazano M.
Published: December 2006

Se ha estudiado la interacción de fosdrín (pesticida organofosforado) con montmorillonita mediante difracción de rayos X y espectroscopia infrarroja. Este insecticida forma con montmorillonita dos tipos de complejos, con espaciados basales 16·05 y 20·06 Å. La formación de uno u otro tipo depende del estado de hidratación y del catión interlaminar de las muestras, de la naturaleza del disolvente y de la concentración de fosdrín. En los espectros de infrarrojo de los complejos, las vibraciones de valencia P =O y C =O del fosdrín se desplazan hacia frecuencias más bajas. La magnitud del desplazamiento de estas vibraciones es función del poder polarizante del catión interlaminar. El desplazamiento de la vibración de valencia C =O depende además del tipo de complejo y de su grado de hidratación. La vibración de valencia C=C se desplaza hacia frecuencias altas en los complejos de espaciado basal 16·05 Å. Los resultados obtenidos indican que el complejo de 16·05 Å es monocapa y que las moléculas de fosdrín (forma trans) deben interaccionar con los cationes interlaminares a través de ambos grupos P =O y C =O. El complejo de 20·06 Å es de dos capas y las moléculas (forma cis) interaccionan solamente a través del grupo P =O.
Structure de l'espace interlamellaire de la vermiculite Mg bicouche
Authors: Alcover J. F. , Gatineau L.
Published: December 2006

L'étude des diffusions, en dehors des taches de Bragg, produites par les molécules d'eau et les cations échangeables des vermiculites magnésium bicouches (d001 ∼ 14·4 Å) permet de proposer un modèle de l'espace interlamellaire. Les groupements cation-molécules d'eau (Mg-12H2O) présentent une organisation bipériodique (maille centrée 3a,b) dans des domaines limités. Chaque motif est constitué par un octaèdre Mg-6H2O auquel est liée fortement une seconde ‘sphère’ d'hydratation, formée également par six molécules d'eau (distances entre atomes d'oxygène des deux sphères d'hydratation de l'ordre de 2·65 Å).
Organisation de l'espace interlamellaire dans les vermiculites monocouches et anhydres
Authors: Rausell-Colom J. A. , Fernandez M. , Serratosa J. M. , Alcover J. F. , Gatineau L.
Published: December 2006

Les vermiculites Mg, Ca, Sr et Ba ont été étudiées par diffraction des rayons X et absorption infra-rouge.

Pour les vermiculites monocouches, l'espacement interréticulaire est compris entre 12·2 et 11·45 Å.

On distingue: (i) les vermiculites Ba; le cation, entouré de 5 à 6 molécules d'eau, est à environ 1Å du plan médian et il intéragit avec un hydroxyle structural du feuillet le plus proche, (ii) les vermiculites Mg, Ca et Sr; le cation, entrouré de 3 ou 4 molécules d'eau,est dans le plan médian ou dans son voisinage (0·3 Å), et il n'interagit pas avec les hydroxyles des feuillets.

Pour les vermiculites anhydres, l'espacement interréticulaire est inférieur à 10 Å, le cation est dans le plan médian et il intéragit avec les hydroxyles de 2 feuillets opposés.

A partir de ces résultats, complétés par les données de la bibliographie, des modéles sont proposés pour représenter l'organisation de l'espace interlamellaire.
Determination, a l'echelle absolue, de l'intensite diffractee aux rayons X par les argiles
Authors: Pons C. H. , Ben Brahim J. , Yücel A. , Tchoubar D. , Tchoubar C.
Published: December 2006

La mesure de l'intensité à l'échelle absolue consiste à déterminer le pouvoir diffusant de l'objet rapporté au motif élémentaire de la structure, c'est-à-dire exprimé en nombre d'électrons libres équivalents diffusant indépendamment et qui donnerait, en chaque point de l'espace réciproque, le même effet que l'objet. Les avantages de cette méthode sont les suivants: (i) elle permet de corriger la courbe expérimentale de la diffusion incohérente et ainsi d'augmenter le nombre de réflexions quantitativement exploitables; (ii) elle permet une meilleure caractérisation de la nature des défauts structuraux et, pour des systèmes hétérogènes tels que des particules en suspensions, elle rend possible la séparation des effets de diffraction spécifiques de chaque phase; (iii) elle rend possible l'interprétation des fonds de diffusion. Ces propriétés sont illustrées sur quelques exemples d'application (kaolinite, sépiolite mal cristallisée et suspension de montmorillonite-Na dans l'eau).
Morfologia y genesis de caolinitas en rocas silicificadas de la provincia de Avila (Espana)
Authors: Marfil R. , Bustillo A. , Garcia Palacios MaC.
Published: December 2006

Se realiza un estudio detallado de las distintas fases minerales (caolínicas y silíceas) que aparecen en rocas silicificadas tanto graniticas como sedimentarias de la provincia de Avila.

Las técnicas utilizadas (A.T.D., difracción de rayos X, microscopía electrónica de trasmisión y de barrido) permiten establecer una clasificación de estos minerales segun sus propiedades térmicas, parámetros cristaloquímicos, y morfologías identificadas al scaning.

Sa dá una interpretación genética a cada uno de los tipos de caolinitas encontrados (macrocaolinitas en acordeón, microcaolinitas en gusanillo y criptocaolinitas). Los dos primeros tipos pueden ser explicados por procesos conjuntos de alteración hidrotermal y ‘weathering’ de feldespatos y micas. El tercer tipo (criptocaolinitas) es de más difícil interpretación al aso-ciarse con ópalo C-T en diques que cortan a rocas granitoideas y otras veces al presentarse como matriz de areniscas sedimentarias.
Etude de la couche interfoliaire des hydrates a deux couches des vermiculites calcique et magnesienne
Authors: Fornés V. , De La Calle C. , Suquet H. , Pezerat H.
Published: December 2006

L'étude porte sur la décomposition du massif de bandes de vibration de valence O-D centré vers 2500 cm−1 que présentent les spectres infrarouge des hydrates à deux couches des vermiculites -Ca et -Mg partiellement deutérées. La détermination des bandes composantes a été effectuée à partir, d'une part de l'étude du dichroïsme des bandes de vibration infrarouge, d'autre part des données structurales disponibles sur les couches interfoliaires de ces minéraux. Ces deux méthodes conduisent—avec un accord satisfaisant—à une décomposition en 4 bandes composantes correspondant à 4 types de liaisons O-D...O. Parmi ces liaisons entre molécules d'eau, certaines sont relativement courtes, ce qui conduit à penser qu'il existe dans la couche interfoliaire de ces hydrates une charpente de molécules d'eau un peu analogue à une charpente anionique.
Adsorption of alcohols by smectites: IV. Models
Authors: Annabi-Bergaya F. , Cruz M. I. , Gatineau L. , Fripiat J. J.
Published: December 2006

In the three previous papers of this series the role played by the exchangeable cations in the adsorption of methanol by homoionic montmorillonites has been investigated by different techniques, namely desorption isotherms, X-ray determination of the basal spacings and IR spectroscopy. In this last paper, models based on the previous discussions are presented. In the adsorbed state, methanol shows a strong tendency to form on the clay surface, hydrogen-bonded zig-zag chains analogous to those in crystalline CH3OH. The exchangeable cations perturb this arrangement to different extents. For Li+ the perturbation is negligible, for Ca2+ a complete rearrangement is observed and for Na+ and Ba2+ the chains are broken into smaller fragments.
A swelling hematite/layer-silicate complex in weathered granite
Authors: Wilson M. J. , Russell J. D. , Tait J. M. , Clark D. R. , Fraser A. R. , Stephen I.
Published: December 2006

A naturally occurring hematitic iron oxide/layer-silicate complex has been found in red mottled patches of a deeply weathered granite in north-east Scotland. X-ray diffraction shows a basal spacing of 36 Å—also observable by high resolution electron microscopy—which expands to 40 Å with glycerol and contracts to 33·5 Å on heating. Selected area electron diffraction reveals a composite hematite/layer-silicate pattern with the a-axis of hematite parallel to the b-axis of the silicate. The IR spectrum of the complex clearly shows the contribution made by each of the components. The silicate, with bands due to OH stretching at 3602 cm−1, OH deformation at 855 cm−1, and Si-O stretching at 1085, 1035, 540 and 471 cm−1 resembles ferruginous pyrophyllite, while the hematite, with a perpendicular band at 647 cm−1, in-plane bands at 519, 438, 400, 302 and 227 cm−1 and a characteristic pattern of relative band intensities, is similar to a platy form of soil hematite. Electron microprobe analysis of individual particles gives the complex an (Fe + Al): Si ratio of 6:1, which is consistent with a structure made up of twelve octahedral sheets terminated on both sides by a silicate sheet. It seems likely that the complex developed from a siliceous ferrihydrite which became progressively more organized with geological time.
Etude en microscopie electronique a balayage de quelques kaolins d'origines differentes: apports de cette technique pour la comprehension de leurs geneses
Authors: Esteoule-Choux J.
Published: December 2006

L'examen des textures de kaolins au M.E.B. apporte des données complémentaires utiles pour la compréhension de leur genèse. Les kaolins provenant d'une altération météorique ont une texture poreuse constitutée par de gros paquets de plaquettes hexagonales empilées de façon lâche ce qui les différencie nettement des kaolins d'origine hydrothermale dont la texture est compacte et la porosité faible. Les kaolins sédimentaires montrent une association de petites plaquettes accolées les unes aux autres quand on les volt suivant les plans de clivage, ou présentent une orientation plus ou moins marquée dans la direction perpendiculaire. Enfin I'observation des textures permet de mesurer I'influence et I'importanee de la diagenèse dans les dépôts argileux.
Depositional facies, diagenetic clay minerals and reservoir quality of Rotliegend sediments in the Southern Permian Basin (North Sea): a review
Authors: Seemann U.
Published: December 2006

The Southern Permian Basin of the North Sea represents an elongate E-W oriented depo-centre along the northern margin of the Variscan Mountains. During Rotliegend times, three roughly parallel facies belts of a Permian desert developed, these following the outline of the Variscan Mountains. These belts were, from south to north, the wadi facies, the dune and interdune facies, and the sabkha and desert lake facies. The bulk of the gas reservoirs of the Rotliegend occur in the aeolian dune sands. Their recognition, and the study of their geometry, is therefore important in hydrocarbon exploration. Equally important is the understanding of diagenesis, particularly of the diageneticaily-formed clay minerals, because they have an important influence on the reservoir quality of these sands. Clay minerals were introduced to the aeolian sands during or shortly after their deposition in the form of air-borne dust, which later formed thin clay films around the grains. During burial diagenesis, these clay films may have acted as crystallization nuclei for new clay minerals or for the transformation of existing ones. Depending on their crystallographic habit, the clay minerals can seriously affect the effective porosity and permeability of the sands.
The brittle mica-like KNiAsO4 and its organic derivatives
Authors: Beneke Klaus , Lagaly Gerhard
Published: December 2006

The nickel arsenate KNiAsO4 has a mica-like layer structure with surface charge densities similar to brittle micas. In contrast to micas it easily exchanges alkylammonium ions. The interlayers have paraffin-type chain arrangements, as in alkylammonium vermiculites and alkylamine smectites and vermiculites, but the very regular chain packing causes a marked odd/even alternation of the basal spacings. The reactions of KNiAsO4 throw light on the exchange behaviour of micas.