bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distinct localization of prokineticin 2 and prokineticin receptor 2 mRNAs in the rat suprachiasmatic nucleus
Authors: Masumoto Koh‐hei , Nagano Mamoru , Takashima Naoyuki , Hayasaka Naoto , Hiyama Hideki , Matsumoto Shun‐ichiro , Inouye Shin‐Ichi T. , Shigeyoshi Yasufumi 
Published: June 2006

AbstractThe suprachiasmatic nucleus (SCN) is the master circadian clock that regulates physiological and behavioral circadian rhythms in mammals. Prokineticin 2 (PK2) is highly expressed in the SCN, and its involvement in the generation of circadian locomotor activity has been reported previously. In the present study, using in situ hybridization methods, we investigated the localization of PK2 and prokineticin receptor 2 (PKR2), a specific receptor for PK2, in the rat SCN. In steady light : dark (L : D = 12 : 12 h) and constant dark conditions, rPK2 mRNA displayed a robust circadian oscillation with a peak occurring during the day. Moreover, during peak expression, the rPK2 mRNA‐positive neurons were scattered in both the dorsomedial and ventrolateral SCN, which are two functionally and morphologically distinct subregions. Furthermore, double‐labeling in situ hybridization experiments revealed that greater than 50% of the rPK2 mRNA‐containing neurons co‐expressed either vasoactive intestinal peptide (VIP), gastrin‐releasing peptide (GRP) or arginine vasopressin (AVP) in the SCN. In contrast, the rPKR2 mRNA levels did not show significant diurnal alterations. rPKR2 mRNA‐containing neurons were also clustered in the dorsolateral part of the SCN, which shows negligible labeling of either rAVP, rVIP, rGRP or rPK2 transcripts. In addition, this region exhibited a delayed cycling of the rPer1 gene. These results suggest an intrinsic PK2 neurotransmission and functionally distinct roles for PKR2‐expressing neurons in the SCN.
Defects in tangential neuronal migration of pontine nuclei neurons in the Largemyd mouse are associated with stalled migration in the ventrolateral hindbrain
Authors: Qu Qiang , Crandall James E. , Luo Tuanlian , McCaffery Peter J. , Smith Frances I. 
Published: June 2006

AbstractThe LARGE gene encodes a putative glycosyltransferase that is required for normal glycosylation of dystroglycan, and defects in LARGE can cause abnormal neuronal migration in congenital muscular dystrophy (CMD). Previous studies have focused on radial migration, which is disrupted at least in part due to breaks in the basal lamina. Through analysis of precerebellar nuclei development in the Largemyd mouse hindbrain, we show that tangential migration of a subgroup of hindbrain neurons may also be disrupted. Within the precerebellar nuclei, the pontine nuclei (PN) are severely disrupted, whereas the inferior olive (IO), external cuneate nuclei (ECN) and lateral reticular nuclei (LRN) appear unaffected. Large and dystroglycan are widely expressed in the hindbrain, including in the pontine neurons migrating in the anterior extramural migratory stream (AES). BrdU labeling and immunohistochemical studies suggest normal numbers of neurons begin their journey towards the ventral midline in the AES in the Largemyd mouse. However, migration stalls and PN neurons fail to reach the midline, surviving as ectopic clusters of cells located under the pial surface dorsally and laterally to where they normally would finish their migration near the ventral midline. Stalling of PN neurons at this location is also observed in other migration disorders in mice. These observations suggest that glycan‐dependent dystroglycan interactions are required for PN neurons to correctly respond to signals at this important migrational checkpoint.
Blockade of glucocorticoid receptors rapidly restores hippocampal CA1 synaptic plasticity after exposure to chronic stress
Authors: Krugers H. J. , Goltstein P. M. , Van Der Linden S. , Joëls M. 
Published: June 2006

AbstractProlonged exposure to stressful events has been reported to inhibit the ability of hippocampal synapses to increase their synaptic efficacy. Here we tested if these effects could be prevented by blocking activation of glucocorticoid receptors during the last 4 days of the stress paradigm. In order to address this question, animals were exposed to 21 days of variable and inescapable stressors. Handled animals served as controls. During the last 4 days of the stress regime, animals were treated with the glucocorticoid receptor antagonist RU486. We found that 1 day after the last stressor, synaptic plasticity in the CA1 area of hippocampal slices is impaired in chronically stressed animals. Importantly, treating chronically stressed animals with RU486 for 4 days completely prevented this decrease in synaptic potentiation; RU486 treatment of handled controls did not affect potentiation. Treating hippocampal slices from control animals with high levels of corticosterone also impaired synaptic plasticity; this effect was similar for untreated and RU486‐treated animals. Treating slices from chronically stressed animals with corticosterone did not further decrease synaptic plasticity. These data indicate that 4 days blockade of the glucocorticoid receptor, during a stress regime, is sufficient to fully restore synaptic plasticity.
Infralimbic cortex projects to all parts of the pontine and medullary lateral tegmental field in cat
Authors: Kuipers Rutger , Mensinga Gabe M. , Boers José , Klop Esther Marije , Holstege Gert 
Published: June 2006

AbstractThe infralimbic cortex (ILc) in cat is the ventralmost part of the anterior cingulate gyrus. The ILc, together with the amygdala, bed nucleus of the stria terminalis and lateral hypothalamus, is involved in the regulation of fear behavior. The latter three structures are thought to take part in triggering the fear response by means of their projections to the pontine and medullary lateral tegmental field (LTF). The LTF is a large region extending from the parabrachial nuclei rostrally to the spinal cord caudally. It contains almost all the premotor interneurons for the brainstem and for some upper spinal cord motoneurons innervating the muscles of face, head and throat. The question is whether ILc also projects to the LTF. Such a pathway would allow the ILc to influence the fear response by acting directly on these premotor interneurons. Anterograde tracer injections were made in the medial surface of the cortex in four cats. Only when the injection sites involved ILc were anterogradely labeled fibers observed throughout the rostrocaudal extent of the LTF. To verify whether these projections indeed originated from ILc, in two other cases retrograde tracer injections were made in the pontomedullary LTF. The results showed many retrogradely labeled neurons in ILc, but none in adjacent cortical regions. These results show that the ILc projects to the LTF in cat and can possibly modulate the fear response not only via indirect but also via direct routes to the premotor interneurons in the brainstem.
Calcium‐induced calcium release in rod photoreceptor terminals boosts synaptic transmission during maintained depolarization
Authors: Cadetti Lucia , Bryson Eric J. , Ciccone Cory A. , Rabl Katalin , Thoreson Wallace B. 
Published: June 2006

AbstractWe examined the contribution of calcium‐induced calcium release (CICR) to synaptic transmission from rod photoreceptor terminals. Whole‐cell recording and confocal calcium imaging experiments were conducted on rods with intact synaptic terminals in a retinal slice preparation from salamander. Low concentrations of ryanodine stimulated calcium increases in rod terminals, consistent with the presence of ryanodine receptors. Application of strong depolarizing steps (−70 to −10 mV) exceeding 200 ms or longer in duration evoked a wave of calcium that spread across the synaptic terminals of voltage‐clamped rods. This secondary calcium increase was blocked by high concentrations of ryanodine, indicating it was due to CICR. Ryanodine (50 µm) had no significant effect on rod calcium current (Ica) although it slightly diminished rod light‐evoked voltage responses. Bath application of 50 µm ryanodine strongly inhibited light‐evoked currents in horizontal cells. Whether applied extracellularly or delivered into the rod cell through the patch pipette, ryanodine (50 µm) also inhibited excitatory post‐synaptic currents (EPSCs) evoked in horizontal cells by depolarizing steps applied to rods. Ryanodine caused a preferential reduction in the later portions of EPSCs evoked by depolarizing steps of 200 ms or longer. These results indicate that CICR enhances calcium increases in rod terminals evoked by sustained depolarization, which in turn acts to boost synaptic exocytosis from rods.
Selective excitotoxic lesions of the hippocampus and basolateral amygdala have dissociable effects on appetitive cue and place conditioning based on path integration in a novel Y‐maze procedure
Authors: Ito Rutsuko , Robbins Trevor W. , McNaughton Bruce L. , Everitt Barry J. 
Published: June 2006

AbstractThe hippocampus and amygdala are thought to be functionally distinct components of different learning and memory systems. This functional dissociation has been particularly apparent in pavlovian fear conditioning, where the integrity of the hippocampus is necessary for contextual conditioning, and of the amygdala for discrete cue conditioning. Their respective roles in appetitive conditioning, however, remain equivocal mainly due to the lack of agreement concerning the operational definition of a ‘context’. The present study used a novel procedure to measure appetitive conditioning to spatial context or to a discrete cue. Following selective excitotoxic lesions of the hippocampus (HPC) or basolateral amygdala (BLA), rats were initially trained to acquire discrete CS‐sucrose conditioning in a Y‐maze apparatus with three topographically identical chambers, the chambers discriminated only on the basis of path integration. The same group of animals then underwent ‘place/contextual conditioning’ where the CS presented in a chamber assigned as the positive chamber was paired with sucrose, but the same CS presented in either of the other two chambers was not. Thus, spatial context was the only cue that the animal could use to retrieve the value of the CS. HPC lesions impaired the acquisition of conditioned place preference but facilitated the acquisition of cue conditioning, while BLA lesions had the opposite effect, retarding the acquisition of cue conditioning but leaving the acquisition of conditioned place preference intact. Here we provide strong support for the notion that the HPC and BLA subserve complementary and competing roles in appetitive cue and contextual conditioning.
Analysis of population genetic structure of two closely related tortricid species of economic importance on macadamias and litchis in South Africa
Authors: Timm A. E. , Geertsema H. , Warnich L. 
Published: June 2006

Abstract

The macadamia nut borer Thaumatotibia (Cryptophlebia) batrachopa and the litchi moth Cryptophlebia peltastica are Afrotropical species causing extensive damage to cultivated macadamias and litchis in the northernmost provinces in South Africa. Cryptophlebia peltastica also occurs as natural populations throughout the country.
To analyse the population genetic structure of the two species, amplified fragment length polymorphism analysis was conducted. Patterns of genetic diversity in C. peltastica populations in the Mpumalanga province, where the species is controlled, were compared with those in the Western Cape, where populations occur under natural conditions.
Gene diversity was high within T. batrachopa populations (H = 0.2219) with significant genetic differentiation among populations (Gst = 0.358). Cluster analysis showed that geographical populations were closely related and extensive divergence was found over local scales.
Similar to that of T. batrachopa, genetic diversity and population differentiation was high within both C. peltastica Mpumalanga and Western Cape populations (H = 0.1906 and 0.1687 and Gst = 0.4124 and 0.3799, respectively).
It is suggested that the population genetic structure of both species is influenced by their limited ability to disperse. In addition, chemical control of C. peltastica in the Mpumalanga province has not succeeded in reducing the population size, but the C. peltastica population subdivision in the Western Cape may be influenced by the limited distribution of host plants in this region.
Struggling to Invent High‐Reliability Organizations in Health Care Settings: Insights from the Field
Authors: Dixon Nancy M. , Shofer Marjorie 
Published: June 2006

The Mission of the Agency for Healthcare Research and Quality (AHRQ) has been to support and conduct health services research and to disseminate those research findings. Recently the Agency has changed its mission to: “Improving the quality, safety, efficiency and effectiveness of health care for all Americans.” For agency personnel working with the topic of patient safety, that change has created a need to develop greater awareness of the current patient safety initiatives underway at leading health care systems in order to determine where AHRQ might best play a role in helping these systems more rapidly adopt new practices to improve patient safety.In order to make that determination, AHRQ conducted a customer needs assessment of leaders in selected health care systems, asking them questions about their current implementation initiatives and their perceived needs for continued implementation of patient safety initiatives. Although not designed or conducted as a research study, the hour‐long interviews produced rich insights into the implementation efforts of patient safety initiatives.The senior leaders interviewed in each of the health care systems, described implementing patient safety initiatives on multiple fronts—in some systems as many as 15 initiatives were underway. As the number of initiatives attests, there was no lack of knowledge about what patient safety practices should be implemented (CPOE, rapid response teams, reduction in surgical site infections) rather the major struggle these health care systems faced was the “how to” of implementation. Most initiatives were only newly begun, so these leaders were not yet confident about what they had learned from these efforts or whether they could be sustained over time. These health care systems drew many of the ideas for initiatives from outside of health care, for example, the nuclear power industry or aviation. The executives expressed concern about a number of issues including: how patient safety initiatives should be sequenced, the lack of benchmarking data to measure their systems against and the pressing need for IT standardization.The insights from this customer needs assessment revealed a wealth of implementation knowledge in the field and has led AHRQ to create an opportunity for leading edge health care systems to learn from each other via learning networks.
How Much Risk Pooling Is There in the Individual Insurance Market?
Authors: Marquis M. Susan , Buntin Melinda Beeuwkes 
Published: June 2006

Objective. To examine how much pooling of risks occurs among potential purchasers in the individual market, how much pooling occurs among those who purchase coverage, and whether there is greater pooling among longer‐term enrollees.Data Sources. The data are administrative records for enrollees in individual insurance plans in California in 2001, and from a survey of Californians enrolled in the individual insurance market and the uninsured.Study Design. Logit models were estimated for 5 health outcome measures to compare the insured and uninsured after adjusting for other factors that affect insurance status and health. Multivariate models were also estimated to explore the relationship between health and three measures of pooling in the market: plan type, pricing tier, and the actuarially adjusted premium paid by the enrollee.Principal Findings. Those who purchase individual health insurance are in better health than those who remain uninsured. On the other hand, a large share of people with health problems does obtain individual insurance. The distribution of subscribers across plan type and pricing tier varies with their health status. Those in poor health are less likely to purchase low benefit plans. There is less separation of risks for those who become sick after enrollment based on the measure of pricing tier. The distribution of subscribers across plan type for those who have health problems at enrollment and those who become sick differs, but so does the distribution of those who become sick and those who remain healthy.Conclusions. Despite small differences among the healthy and sick, our results support the conclusion that there is considerable risk pooling in the individual market. To some extent, this pooling occurs because underwriting happens at the time people enroll and there is greater pooling among those who become sick than those who enroll sick. Our results however suggest that health savings accounts may further fragment the market.
Provider Attitudes toward Pay‐for‐Performance Programs: Development and Validation of a Measurement Instrument
Authors: Meterko Mark , Young Gary J. , White Bert , Bokhour Barbara G. , Burgess James F. , Berlowitz Dan , Guldin Matthew R. , Nealon Seibert Marjorie 
Published: June 2006

Objective. To develop an instrument for assessing physician attitudes toward quality incentive programs, and to assess its reliability and validity.Data Sources. Study involved primary data collection. A 40‐item paper and pencil survey of primary care physicians in Rochester, New York, and Massachusetts was conducted between May 2004 and December 2004. Seven‐hundred and ninety‐eight completed questionnaires were received, representing a response rate of 32 percent (798/2,497).Study Design. Based on an extensive review of the literature and discussions with experts in the field, we developed a conceptual framework representing the features of pay‐for‐performance (P4P) programs hypothesized to affect physician behavior in that context. A draft questionnaire was developed based on that conceptual model and pilot tested in three groups of physicians. The questionnaire was modified based on the physician feedback, and the revised version was distributed to 2,497 primary care physicians affiliated with two of the seven sites participating in Rewarding Results, a national evaluation of quality target and financial incentive programs.Data Collection. Respondents were randomly divided into a derivation and a validation sample. Exploratory factor analysis was applied to the responses of the derivation sample. Those results were used to create scales in the validation sample, and these were then subjected to multitrait analysis (MTA). One scale representing physicians' perception of the impact of P4P on their clinical practice was regressed on the other scales as a test of construct validity.Principal Findings. Seven constructs were identified and demonstrated substantial convergent and discriminant validity in the MTA: awareness and understanding, clinical relevance, cooperation, unintended consequences, control, financial salience, and impact. Internal consistency reliabilities (Cronbach's α coefficients) ranged from 0.50 to 0.80. A statistically significant 25 percent of the variation in perceived impact was accounted for by physician perceptions of the other six characteristics of P4P programs.Conclusions. It is possible to identify and measure the key salient features of P4P programs using a valid and reliable 26‐item survey. This instrument may now be used in further studies to better understand the impact of P4P programs on physician behavior.
Invertebrate and Vertebrate Seed Predation in the Amazonian Palm Attalea maripa1
Authors: Salm Rodolfo 
Published: June 2006

ABSTRACTSpatial‐scale‐dependent patterns of Attalea maripa seed predation and removal by the beetle Pachymerus cardo and vertebrates were examined in a palm patch and its adjacent forest in southeastern Amazon. Seed survivorship depended on the distance from the palm patch, but was unrelated to distance from individual fruiting palms.
An Effective Numerical Approach for Multiple Void-Crack Interaction
Authors: Yan Xiangqiao 
Published: June 2006

AbstractThis paper presents a numerical approach to modeling a general system containing multiple interacting cracks and voids in an infinite elastic plate under remote uniform stresses. By extending Bueckner’s principle suited for a crack to a general system containing multiple interacting cracks and voids, the original problem is divided into a homogeneous problem (the one without cracks and voids) subjected to remote loads and a multiple void-crack problem in an unloaded body with applied tractions on the surfaces of cracks and voids. Thus the results in terms of the stress intensity factors (SIFs) can be obtained by considering the latter problem, which is analyzed easily by means of the displacement discontinuity method with crack-tip elements (a boundary element method) proposed recently by the author. Test examples are included to illustrate that the numerical approach is very simple and effective for analyzing multiple crack/void problems in an infinite elastic plate. Specifically, the numerical approach is used to study the microdefect-finite main crack linear elastic interaction. In addition, complex crack problems in infinite/finite plate are examined to test further the accuracy and robustness of the boundary element method.
Stability and Andronov-Hopf Bifurcation of Steady-State Motion of
Rotor System Partly Filled With Liquid: Continuous and Discrete
Models
Authors: Derendyaev N. V. , Vostrukhov A. V. , Soldatov I. N. 
Published: June 2006

Abstract
In this paper, a new method for investigation of dynamics of fluid-filled rotor systems is presented. The method consists of development of finite degrees-of-freedom (discrete) models for the rotor systems. The discrete models are physically justified and demonstrative. Being described by the system of ordinary differential equations, they allow one to employ powerful tools of the theoretical mechanics and oscillation theory. The method is applied to the case of the plane model of the rotor system partly filled with incompressible liquid. Both the continuous and discrete models are considered. The main attention is paid to the latter model. The discrete model consists of a disk symmetrically fixed on the shaft (Laval scheme), the ends of which are in viscoelastic bearings, and a ring sliding over the disk with friction. The centers of the disk and ring are elastically connected. The disk models the rotor, while the ring describes the liquid filling. When the ring is sliding over the disk surface, an interaction force arises that is diverted from the direction of the relative velocity at the contact points. It is demonstrated that an appropriate choice of the parameters of the discrete model allows one to determine the stability domain of the steady-state rotation of the rotor in the plane of the parameters of the shaft bearings with an excellent accuracy. It is found out that when the parameters overstep the limits of the stability domain, the Andronov-Hopf bifurcation occurs: a periodic motion of a kind of a circular precession arises from the steady-state rotation regime either “softly” or “hardly.”