bluuebunny/crossref_metadata_2025 huggingface dataset:
Intravenous Thrombolysis in Posterior Cerebral Artery Infarctions
Authors: Breuer L. , Huttner H.B. , Jentsch K. , Blinzler C. , Winder K. , Engelhorn T. , Köhrmann M.
Published: February 2011

Background: Approximately 5–10% of all acute ischemic strokes (AIS) occur in the territory of the posterior cerebral artery (PCA). Little is known about intravenous thrombolysis (IVT) in this infarct subgroup in terms of outcome and intracerebral hemorrhage rates. The aim of our study was to evaluate differences between supratentorial PCA infarcts and anterior circulation infarcts regarding baseline characteristics, stroke severity, outcome, safety and clinical findings, which would implicate a change in the existing thrombolysis practice in patients with PCA stroke. Methods: All patients with AIS in the supratentorial PCA territory receiving IVT between 01/2006 and 01/2010 were selected from the Erlangen Thrombolysis Database (group 1, n = 21). They were compared to all IVT patients with strokes in other supratentorial vascular territories over the same period of time (group 2, n = 398). Baseline demographic data, as well as clinical and laboratory findings were analyzed. The outcome was assessed using the modified Rankin Scale at 3 months. Results: Only serum glucose levels at baseline (110.5 ± 36.1 vs. 127.2 ± 48.2 mg/dl; p = 0.036) and the baseline National Institutes of Health Stroke Scale score (median 6.5 vs. 9; p = 0.016) were significantly lower in group 1 compared to group 2. Favorable clinical outcome (57.1 vs. 48.6%; p = 0.445) and intracerebral hemorrhage rates (4.8 vs. 4%; p = 1.000) were comparable in both groups. Conclusions: No substantial differences were found between supratentorial PCA and anterior circulation infarcts. Our data on safety and efficacy support the present common thrombolysis practice in supratentorial PCA infarct patients, though an indication for IVT should rather be based on the existence of functionally disabling deficit than merely on the National Institutes of Health Stroke Scale.
Cervical Spinal Dysraphism
Authors: Kıymaz Nejmi , Yılmaz Nebi , Güdü Burhan Oral , Demir İsmail , Kozan Abdulbaki
Published: February 2011

Objective: Cervical spinal dysraphism is a rare congenital spinal pathology. The results obtained from our series are compared with the results obtained from other series of studies in the literature. Methods: Seven patients with cervical myelomeningocele and meningocele who underwent surgery between January 1996 and March 2009 at the YYU Faculty of Medicine in the Department of Neurosurgery were retrospectively studied. Results: The referral ages of the patients (6 females and 1 male) varied between 4 days and 4 months (median 1 month). A stalk lesion covered with a dysplastic skin formed as a sac and located at the cervical midline was demonstrated in all of the patients. Cervical myelomeningocele was present in 4 patients, while cervical meningocele was present in 3 patients; however, Chiari type II malformation and hydrocephaly were present in 3 patients with myelomeningoceles. Diastematomyelia and a filum terminal lipoma were present in 1 of the patients. Conclusion: In this series, in contrast to the literature, we noted that the number of girls with spinal dysraphism with a cervical myelomeningocele and meningocele was greater than the number of boys. Chiari type II malformation, hydrocephaly and motor weakness in patients with cervical spinal dysraphism are less frequent when compared to patients with caudal spinal dysraphism. The structure of the sac is also more durable and, accordingly, a cerebrospinal fluid leakage is uncommon.
Identifying and Characterizing Trajectories of Cognitive Change in Older Persons with Mild Cognitive Impairment
Authors: Xie Haiqun , Mayo Nancy , Koski Lisa
Published: February 2011

Background: Mild cognitive impairment (MCI) represents a state of high risk for dementia but is heterogeneous in its course. To date, the trajectories reflecting distinct developmental courses of cognition among patients with MCI have not been well defined. Aim: To identify the developmental trajectory of groups with distinct cognitive change patterns among a cohort of MCI patients. Methods: 187 MCI patients from 2 geriatric outpatient clinics were evaluated serially with the Mini-Mental State Examination (MMSE) for up to 3.5 years. Group-based trajectory analysis was applied to identify distinct trajectories. Estimates of decline for each group were compared with the mean rate of decline obtained from mixed modeling of the entire sample. Results: 5 trajectories were identified and labeled based on their baseline MMSE score and course: (1) 29/stable (6.5%); (2) 27/stable (53.9%); (3) 25/slow decline (23.8%); (4) 24/slow decline (11.6%); (5) 25/rapid decline (4.2%). Annual rate of change in the MMSE score for these 5 groups was 0.09, –0.43, –1.23, –1.84, and –4.6 points, respectively. None corresponded to the mean rate of –0.82 points estimated for the group as a whole. A majority of MCI patients (60.4%) follow stable cognitive trajectories over time. Within the 3 groups with declining trajectories, cognitive decline occurs slowly in a vast majority of MCI patients (98.5%). Conclusions: Results provide direct evidence for the heterogeneous course of cognitive decline that has been suggested by the variable prognosis for patients with MCI.
Artist as Mediator: The History of the US Department of Art & Technology (2000–2005)
Authors: Packer Randall
Published: February 2011

I moved to Washington, DC, at the turn of the millennium. Shortly after September 11th, I found myself with a job to do, an artist in the center of power during times of crisis. I held a desire to engage, not as a passive observer, but with an active role—the artist's role, one who sees, listens, analyzes, translates and illuminates the dangerous mechanisms of the unfolding political situation in America. This resulted in the founding of the US Department of Art & Technology. The following narrative account is a portrait of the artist as mediator “between a strange, hostile world and the human spirit.”
Strategic Corporate Social Responsibility and Environmental Sustainability
Authors: Orlitzky Marc , Siegel Donald S. , Waldman David A.
Published: February 2011

The authors review three theoretical approaches to strategic corporate social responsibility (CSR), which can be defined as voluntary CSR actions that enhance a firm’s competitiveness and reputation. The end result of such activities should be an improvement in financial and economic performance. Based on an overview of recent empirical evidence, the authors conclude that economic theories of strategic CSR have the greatest potential for advancing this field of inquiry, although theories of strategic leadership should also be incorporated into this perspective. In the remainder of the article, they provide focused summaries of the articles presented in this special issue and outline an agenda for future research on strategic CSR and environmental sustainability.
Measuring Environmental Strategy: Construct Development, Reliability, and Validity
Authors: Walls Judith L. , Phan Phillip H. , Berrone Pascual
Published: February 2011

Inconsistent results in prior work that link environmental strategy to competitive advantage may be due to the empirical difficulties of marrying the theoretical connection between a firm’s resource base and its environmental strategy. The authors contribute to the field by developing a measure that is congruent with the natural resource—based view, a dominant paradigm in this line of work. This article content analyses company reports and secondary data to develop a measure of environmental strategy grounded in the natural resource—based view. They identify six environmental capabilities that form components of a reliable, multidimensional construct of proactive environmental strategy. They also identify a measure of reactive compliance strategy. They verify reliability of their new measure through exploratory and confirmatory factor analyses, establish convergent and discriminant validity via a multitrait, multimethod matrix and demonstrate superior predictive validity of their measure compared to two others commonly used in the literature. In the conclusion, they discuss implications for research and practice.
Predictors of Employment Outcomes for Vocational Rehabilitation Consumers With HIV/AIDS: 2002–2007
Authors: Jung Youngoh , Bellini James L.
Published: February 2011

This study examined the predictability of two employment outcomes—employment status and weekly earnings at closure— from consumer demographic, medical, and service variables for multiple groups of vocational rehabilitation (VR) consumers with HIV/AIDS retrieved from the RSA-911 data for fiscal years 2002 through 2007. A logistic regression analysis was used to determine predictors of employment status at closure across years, and a multiple regression analysis was conducted to identify predictors of weekly wage at closure. Consistently significant predictors of employment status at closure across the 6 years of data included job placement assistance, service expenditures, and length of time in rehabilitation. Consumer demographic variables, including receipt of Supplemental Security Income/Social Security Disability Income at referral, Medicare/Medicaid at referral, and level of education along with receipt of training services (i.e., college, vocational, or on-the-job training), were found to be the most reliable, significant predictors of weekly earnings at closure across the 6 years. Implications of the findings for practice and research are provided.
Discussion of “The Effect of Research and Development (R&D) Inputs and Outputs on the Relation between the Uncertainty of Future Operating Performance and R&D Expenditures”
Authors: Sougiannis Theodore
Published: February 2011

Pandit, Wasley, and Zach (2011) examine whether both research and development (R&D) input (R&D expenditures) and output measures (patent counts and citations) and their interaction associate with the level and variability of future earnings and operating cash flows. The associations examined contribute to the literature because they help determine whether the relationship between firm-level innovation and operating performance is conditional on the success of a firm’s R&D efforts. The conditioning is important because it can sort out more successful from less successful R&D firms. In my discussion, I focus on the models employed and on the empirical results. Some results are consistent with expectations and some other results are not. I think that the mixed results are due to the models employed and I make some suggestions for model improvements.
Pay for Performance: Keep it Simple and Value-Focused
Authors: Branch William J. , Farris Paul W. , Haskins Mark E.
Published: February 2011

In this article, the authors describe a simple but sophisticated four-step process for adjusting the widely relied on operating manager’s incentive compensation performance metric of earnings before interest, taxes, depreciation and amortization (EBITDA) to align with the shareholder-oriented economic profit metric. The approach, which is termed EV-Pay, follows three principles: (a) any incentive compensation plan must be understood by and relevant to operating managers, (b) it should reward managers for earnings that exceed a risk-adjusted return on capital, and (c) it should be based on the economic profits that accrue to shareholders. The EV-Pay process operationalizes the economic profit construct for incentive compensation purposes in corporate environments where economic profit is not otherwise used.
ESOP Distribution Policies
Authors: Burgess M. John
Published: February 2011

Sponsors of employee stock ownership plans may have a distribution policy to govern how distributions from the plan will be made. Frequently, these policies are afterthoughts and drafted without considering the sponsor’s unique circumstances. However, with the Internal Revenue Service reportedly ready to ask employee stock ownership plan sponsors to provide a copy of the plan’s distribution policy as a part of the determination letter process, sponsors should take a fresh look at their distribution policy or prepare one if a policy is not in place. The policy should be carefully thought out to meet the sponsor’s needs while balancing several competing interests.
Crime Travel Demand and Bank Robberies
Authors: Levine Ned
Published: February 2011

A crime travel demand model was applied to 258 bank robberies that occurred in Baltimore County, Maryland, between 1993 and 1997 to understand the likely travel patterns of bank robbers. The data are assigned to both origin and destination traffic analysis zones, and a predictive model is developed to understand the correlates of the zones where offenders live and those of the zones where the bank robberies occurred. The results support the hypothesis of a vehicle trip from a poorer, denser neighborhood to a nearby bank that was located in a commercial area on a major arterial. Plausible travel routes are analyzed, and an escape route scenario is developed. The results have implications for policing and provide insights into the likely escape routes that bank robbers would use.
The Impact of Mobilization Media on Off-Line and Online Participation: Are Mobilization Effects Medium-Specific?
Authors: Vissers Sara , Hooghe Marc , Stolle Dietlind , Mahéo Valérie-Anne
Published: February 2011

In recent years, voluntary associations and political organizations have increasingly switched to Internet-based mobilization campaigns, replacing traditional forms of face-to-face recruitment and mobilization. The existing body of empirical research on Internet-based mobilization, however, is not conclusive about the effects this form of mobilization might have. In this article, the authors argue that this lack of strong conclusions might be due to the failure to distinguish different behavioral outcomes of mobilization, and more specifically, a distinction between online and off-line forms of participation is missing. In this experimental study, participants were exposed to potentially mobilizing information either by way of face-to-face interaction or by website. The results of the experiment indicate that web-based mobilization only has a significant effect on online participation, whereas face-to-face mobilization has a significant impact on off-line behavior, which would imply that mobilization effects are medium-specific. The authors close with some observations on what these findings might imply for the democratic consequences of the current trend toward an increasing reliance on Internet-based forms of political mobilization.
Child Pornography Possessors: Trends in Offender and Case Characteristics
Authors: Wolak Janis , Finkelhor David , Mitchell Kimberly
Published: February 2011

This article describes trends in child pornography (CP) possession cases that ended in arrest in 2000 and in 2006, using data from the National Juvenile Online Victimization Study, a two-wave longitudinal survey of a national sample of more than 2,500 U.S. law enforcement agencies. In 2006, there were an estimated 3,672 arrests for CP possession, compared with 1,713 arrests in 2000. Many characteristics of the offenders and the offense remained stable. In both 2006 and 2000, most offenders were White, non-Hispanic males and socioeconomically diverse. Few were known to have committed previous sex crimes. Most had CP that depicted preteen children and serious sexual abuse. In 2006, however, a higher proportion of offenders were aged 18 to 25 years, used peer-to-peer (p2p) networks, had images of children younger than 3 years, and had CP videos. P2p users had more extreme images (e.g., younger victims, sexual violence) and larger numbers of images than those who did not use p2p networks. Findings reflect heightened efforts in the criminal justice system to combat CP crimes. More cases originated with investigations of CP possession and involved proactive investigations aimed at detecting CP. The great majority of cases were successfully prosecuted, with more offenders sentenced to incarceration and serving longer sentences than in 2000. As in 2000, one in six cases that began with investigations of CP possession detected offenders who had molested children.
A Cultural Paradox: Elder Abuse in the Native American Community
Authors: Smyer Tish , Clark Michele C.
Published: February 2011

An emerging cultural paradox in the Native American community is the long history of respect for elders and the emergence of elder abuse as a problem. Elders commonly hold a special and respected place in traditional Native American societies due largely to their experience, knowledge, wisdom, and power as dreamers, healers, and teachers. Although violence against other tribal members is considered as unnatural and a threat to internal spiritual harmony, victimization, and abuse of elders and is recognized as a clandestine but increasing problem in the Native American community. This challenges health care providers and tribal members to provide safe and culturally congruent care to the elderly as well as coming to terms with this cultural paradox. There is a growing commitment by tribes to address this problem and to provide and honor the Native American elder. This article provides information for health care providers to better understand elder abuse in the cultural context of the Native American community as well implications for care.
Putting the positive in health psychology: A content analysis of three journals
Authors: Schmidt Christa K. , Raque-Bogdan Trisha L. , Piontkowski Sarah , Schaefer Kathryn L.
Published: February 2011

This content analysis investigated the inclusion of positive psychological constructs in research published in three leading health psychology journals. A list of positive constructs relevant to health psychology was compiled and their inclusion in these journals was examined. It was found that although there has been a sharp increase in recent years, only 3 percent of all articles published (114 of 3789) included the study of overtly positive constructs. The constructs that have been most and least studied in health psychology were identified and are discussed. This analysis provides insight into the foundations of positive health psychology and identifies future directions.
PTSD after Traumatic Injury: An Investigation of the Impact of Injury Severity and Peritraumatic Moderators
Authors: Gabert-Quillen Crystal A. , Fallon William , Delahanty Douglas L.
Published: February 2011

Presence of injury is often examined as a risk factor for posttraumatic stress disorder (PTSD); however, results have been mixed regarding the relationship between injury severity and PTSD symptoms (PTSS). The present study examined subjective and objective injury severity ratings in traumatic injury victims to determine if they differentially predict PTSS. Results demonstrated that subjective, not objective, injury severity predicted PTSS at six weeks and three months post-trauma. The moderating impact of peritraumatic factors was also examined. Peritraumatic dissociation moderated the impact of subjective injury severity on PTSS. Findings indicate that subjective injury severity should be incorporated into early screeners for PTSD risk.
Social Identity and Convergence: News Faculty and Student Perspectives on Web, Print, and Broadcast Skills
Authors: Hubbard Glenn T. , Crisp Crawford Elizabeth , Filak Vincent F.
Published: February 2011

This research examines the role of intergroup bias in mass communication students and faculty perceptions of the importance of various media technology skills. This study differs from previous research because it compares the views of both print journalism and broadcasting students and faculty about media skills and convergence. A scale of social identity pinpoints a relationship between social psychology and attitudes about media skills. A weak negative correlation between the absolute value of the print-minus-broadcast skills-preference variable and web-skills preferences among all mass communication student and faculty participants was found, and the correlation strengthened when only broadcast students and faculty were analyzed, indicating that those inclined toward broadcasting were more likely to prefer traditional mass media skills training over cross-platform, new media, and Internet skills. Broadcast students and faculty also differed from other participants in how their preferences for the skills of their own profession relate to their openness to nontraditional media skills. Students reported a greater preference for skills training than faculty did. Comparisons of students and faculty preferences for print, broadcast, and web skills showed strong, statistically significant differences, with students rating all skills more highly than faculty did.
A mouse model of hereditary folate malabsorption: deletion of the PCFT gene leads to systemic folate deficiency
Authors: Salojin Konstantin V. , Cabrera Robert M. , Sun Weimei , Chang Wei Chun , Lin Colin , Duncan Lindsay , Platt Ken A. , Read Robert , Vogel Peter , Liu Qingyun , Finnell Richard H. , Oravecz Tamas
Published: February 2011

The human proton coupled folate transporter (PCFT) is involved in low pH-dependent intestinal folate transport. In this report, we describe a new murine model of the hereditary folate malabsorption syndrome that we developed through targeted disruption of the first 3 coding exons of the murine homolog of the PCFT gene. By 4 weeks of age, PCFT-deficient (PCFT−/−) mice developed severe macrocytic normochromic anemia and pancytopenia. Immature erythroblasts accumulated in the bone marrow and spleen of PCFT−/− mice and failed to differentiate further, showing an increased rate of apoptosis in intermediate erythroblasts and reduced release of reticulocytes. In response to the inefficient hematologic development, the serum of the PCFT−/− animals contained elevated concentrations of erythropoietin, soluble transferrin receptor (sCD71), and thrombopoietin. In vivo folate uptake experiments demonstrated a systemic folate deficiency caused by disruption of PCFT-mediated intestinal folate uptake, thus confirming in vivo a critical and nonredundant role of the PCFT protein in intestinal folate transport and erythropoiesis. The PCFT-deficient mouse serves as a model for the hereditary folate malabsorption syndrome and is the most accurate animal model of folate deficiency anemia described to date that closely captures the spectrum of pathology typical of this disease.
China and the Question of Freedom
Authors: Ci Jiwei
Published: February 2011

In three decades of reform China has become a society that is radically different both from what it used to be in Mao's time and from a liberal society. This new China poses especially interesting questions about freedom—interesting not only in the Chinese context but also more generally. Pivotal for my treatment of these questions is a distinction I draw between de facto freedom and the value of freedom, the latter in turn understood in terms of a larger notion of agency, and divided into such distinct dimensions as moral resource, right, and mode of subjection. This distinction allows me to argue that while China has no shortage of de facto freedom, it lacks the value of freedom, especially freedom as a mode of subjection. The lack of freedom as a value has serious moral and political consequences, as manifested in a prolonged moral crisis in post-Mao China and in a certain fragility of social order caused by the pitting of order against freedom. Such consequences suggest a strong need for China to develop the value of freedom. But it is possible and important to do so in a critical spirit, as I argue through a critical analysis of the place of freedom in a liberal society.
Confucius the Chameleon: Dubious Envoy for “Brand China”
Authors: Louie Kam
Published: February 2011

In the last century, scholars and politicians in China have attempted both in theory and in practice to advocate and carry out radically different social policies and political reforms, often in the name of Confucius. With China's rise and her increasing international power and status in recent years, Chinese policy makers have again used the Confucius label as part of their “charm offensive” to win friends and influence in the world.

This essay traces the major interpretations of Confucius and the social manifestations of those evaluations in the twentieth century, culminating in the establishment and mushrooming of Confucius Institutes throughout the world in the last few years. While the globalization of Chinese culture is inevitable, the attempts to name and institutionalize it as modernized Confucianism has the effect of injecting inconsistencies into a system that is already overflowing with internal contradictions and inequities.
An evolutionarily conserved, alternatively spliced, intron in the p68/DDX5 DEAD-box RNA helicase gene encodes a novel miRNA
Authors: Moore Hayley C. , Johnston Michael , Nicol Samantha M. , Bourdon Jean-Christophe , Thompson Alastair M. , Hutvagner Gyorgy , Fuller-Pace Frances V.
Published: February 2011

The DEAD-box RNA helicase p68 (DDX5) plays important roles in several cellular processes, including transcription, pre-mRNA processing, and microRNA (miRNA) processing. p68 expression is growth and developmentally regulated, and alterations in p68 expression and/or function have been implicated in tumor development. The p68 gene encodes an evolutionarily conserved, alternatively spliced, intron the function of which has to date remained unclear. Although the intron-containing p68 RNA does not appear to yield an alternative p68 protein, it is differentially expressed in cell lines and tissues, indicating regulation of expression. Here we show that the p68 conserved intron encodes a novel putative miRNA, suggesting a previously unknown possible regulatory function for the p68 intron. We show that this miRNA (referred to as p68 miRNA) is processed from the intron via the canonical miRNA-processing pathway and that it associates with the Argonaute protein Ago2. Finally we show that the p68 miRNA suppresses an mRNA bearing complementary target sequences, suggesting that it is functional. These findings suggest a novel mechanism by which alterations in p68 expression may impact on the cell.
Theorizing Practice and Practicing Theory
Authors: Feldman Martha S. , Orlikowski Wanda J.
Published: February 2011

This paper describes the emerging field of practice theory as it is practiced in relation to organizational phenomena. We identify three approaches—empirical, theoretical, and philosophical—that relate to the what, the how, and the why of using a practice lens. We discuss three principles of the theoretical approach to practice and offer examples of how practice theory has been used in the organizational literature and in our own research. We end with a discussion of the challenges and opportunities that practice theory affords organizational scholarship.
HPV L1 Capsid Protein Detection and Progression of Anal Squamous Neoplasia
Authors: Hernandez Jonathan , Elahi Abul , Siegel Erin , Coppola Domenico , Riggs Bridgett , Shibata David
Published: February 2011

The progression of cervical intraepithelial lesions to invasive cancer is associated with corresponding reductions in human papillomavirus (HPV) L1 capsid antigen (L1) expression. We sought to determine whether a similar loss of L1 occurs during anal carcinogenesis using immunohistochemistry on paraffin-embedded sections as well as INNO-LiPA HPV Genotyping (Innogenetics, Gent, Belgium) technology to determine HPV infection status. We analyzed 31 squamous cell carcinomas (SCCs), 26 SCCs in situ (SCC-IS), and 11 normal anal mucosae from 36 patients. High-risk HPV subtypes were detected in all patients. L1 nuclear staining was identified in 38% of SCC-IS; however, there was no detection in normal anal mucosae, SCC, or recurrent SCC. Of those SCC-IS associated with a concomitant invasive SCC, only 15% demonstrated nuclear L1 expression as compared to 62% of isolated SCC-IS (P = .02). Nuclear expression of L1 is lost in the progression of anal SCC-IS to SCC and may serve as a possible prognostic marker of enhanced malignant potential.
Refractory Anemia With Ring Sideroblasts Associated With Marked Thrombocytosis
Authors: Gurevich Inga , Luthra Raja , Konoplev Sergej N. , Yin C. Cameron , Medeiros L. Jeffrey , Lin Pei
Published: February 2011

Refractory anemia with ring sideroblasts associated with marked thrombocytosis (RARS-T) is a provisional entity in the current World Health Organization classification and is thought to be a myelodysplastic/myeloproliferative neoplasm (MDS/MPN). We analyzed 18 cases of RARS-T. All patients had thrombocytosis (platelet count, 515–1,100 × 103/μL [515–1,100 × 109/L]) and anemia (hemoglobin level, 7.2–12.6 g/dL [72–126 g/L]). Three patients had mild leukocytosis (WBC count, 3,900–16,300/μL [3.9–16.3 × 109/L]). Ring sideroblasts were 8% to 75% in the bone marrow. Megakaryocytes showed a spectrum of morphologic findings. JAK2V617F was identified in 9 of 15 cases, including 7 of 9 with thrombocytosis (platelet count, >600 × 103/μL [600 × 109/L]) and 1 with 8% ring sideroblasts. The MPLW515L mutation was not detected (n = 9). We conclude that RARS-T is a pathogenetically heterogeneous group of limited diagnostic usefulness. Approximately 60% of cases carry JAK2V617Fand seem to be closer to an MPN in which ring sideroblasts may be a secondary phenomenon. The remaining cases usually lack the JAK2V617Fmutation, have a platelet count less than 600 × 103/μL (600 × 109/L), and may represent an MDS or MPN with thrombocytosis of unknown mechanisms.
Symmetries in Steinhaus Triangles and in Generalized Pascal Triangles
Authors: Brunat Josep M. , Maureso Montserrat
Published: February 2011

We give explicit formulae for obtaining the binary sequences which produce Steinhaus triangles and generalized Pascal triangles with rotational and dihedral symmetries.
Van der Waerden's Theorem and Avoidability in Words
Authors: Au Yu-Hin , Robertson Aaron , Shallit Jeffrey
Published: February 2011

Independently, Pirillo and Varricchio, Halbeisen and Hungerbühler and Freedman considered the following problem, open since 1992: Does there exist an infinite word
Inverse problems for quantum kinetic equations
Authors: Anikonov Yu. E. , Neshchadim M. V.
Published: February 2011

In the paper the differential identity was obtained for quantum kinetic equation. On the basis of this identity the theorem of uniqueness of inverse problem of determining the solution and right-hand was proved given the boundary and initial information. The problem of recovery of the solution and potential was considered. Also, the solution in the quasipolynomial form was constructed.
Topographic Mapping of a Hierarchy of Temporal Receptive Windows Using a Narrated Story
Authors: Lerner Yulia , Honey Christopher J. , Silbert Lauren J. , Hasson Uri
Published: February 2011

Real-life activities, such as watching a movie or engaging in conversation, unfold over many minutes. In the course of such activities, the brain has to integrate information over multiple time scales. We recently proposed that the brain uses similar strategies for integrating information across space and over time. Drawing a parallel with spatial receptive fields, we defined the temporal receptive window (TRW) of a cortical microcircuit as the length of time before a response during which sensory information may affect that response. Our previous findings in the visual system are consistent with the hypothesis that TRWs become larger when moving from low-level sensory to high-level perceptual and cognitive areas. In this study, we mapped TRWs in auditory and language areas by measuring fMRI activity in subjects listening to a real-life story scrambled at the time scales of words, sentences, and paragraphs. Our results revealed a hierarchical topography of TRWs. In early auditory cortices (A1+), brain responses were driven mainly by the momentary incoming input and were similarly reliable across all scrambling conditions. In areas with an intermediate TRW, coherent information at the sentence time scale or longer was necessary to evoke reliable responses. At the apex of the TRW hierarchy, we found parietal and frontal areas that responded reliably only when intact paragraphs were heard in a meaningful sequence. These results suggest that the time scale of processing is a functional property that may provide a general organizing principle for the human cerebral cortex.
Cell Assembly Sequences Arising from Spike Threshold Adaptation Keep Track of Time in the Hippocampus
Authors: Itskov Vladimir , Curto Carina , Pastalkova Eva , Buzsáki György
Published: February 2011

Hippocampal neurons can display reliable and long-lasting sequences of transient firing patterns, even in the absence of changing external stimuli. We suggest that time-keeping is an important function of these sequences, and propose a network mechanism for their generation. We show that sequences of neuronal assemblies recorded from rat hippocampal CA1 pyramidal cells can reliably predict elapsed time (15–20 s) during wheel running with a precision of 0.5 s. In addition, we demonstrate the generation of multiple reliable, long-lasting sequences in a recurrent network model. These sequences are generated in the presence of noisy, unstructured inputs to the network, mimicking stationary sensory input. Identical initial conditions generate similar sequences, whereas different initial conditions give rise to distinct sequences. The key ingredients responsible for sequence generation in the model are threshold-adaptation and a Mexican-hat-like pattern of connectivity among pyramidal cells. This pattern may arise from recurrent systems such as the hippocampal CA3 region or the entorhinal cortex. We hypothesize that mechanisms that evolved for spatial navigation also support tracking of elapsed time in behaviorally relevant contexts.
A Comparison of Vestibular Spatiotemporal Tuning in Macaque Parietoinsular Vestibular Cortex, Ventral Intraparietal Area, and Medial Superior Temporal Area
Authors: Chen Aihua , DeAngelis Gregory C. , Angelaki Dora E.
Published: February 2011

Vestibular responses have been reported in the parietoinsular vestibular cortex (PIVC), the ventral intraparietal area (VIP), and the dorsal medial superior temporal area (MSTd) of macaques. However, differences between areas remain largely unknown, and it is not clear whether there is a hierarchy in cortical vestibular processing. We examine the spatiotemporal characteristics of macaque vestibular responses to translational motion stimuli using both empirical and model-based analyses. Temporal dynamics of direction selectivity were similar across areas, although there was a gradual shift in the time of peak directional tuning, with responses in MSTd typically being delayed by 100–150 ms relative to responses in PIVC (VIP was intermediate). Responses as a function of both stimulus direction and time were fit with a spatiotemporal model consisting of separable spatial and temporal response profiles. Temporal responses were characterized by a Gaussian function of velocity, a weighted sum of velocity and acceleration, or a weighted sum of velocity, acceleration, and position. Velocity and acceleration components contributed most to response dynamics, with a gradual shift from acceleration dominance in PIVC to velocity dominance in MSTd. The position component contributed little to temporal responses overall, but was substantially larger in MSTd than PIVC or VIP. The overall temporal delay in model fits also increased substantially from PIVC to VIP to MSTd. This gradual transformation of temporal responses suggests a hierarchy in cortical vestibular processing, with PIVC being most proximal to the vestibular periphery and MSTd being most distal.
Behavioral Choice between Conflicting Alternatives Is Regulated by a Receptor Guanylyl Cyclase, GCY-28, and a Receptor Tyrosine Kinase, SCD-2, in AIA Interneurons ofCaenorhabditis elegans
Authors: Shinkai Yoichi , Yamamoto Yuta , Fujiwara Manabi , Tabata Takashi , Murayama Takashi , Hirotsu Takaaki , Ikeda Daisuke D. , Tsunozaki Makoto , Iino Yuichi , Bargmann Cornelia I. , Katsura Isao , Ishihara Takeshi
Published: February 2011

Animals facing conflicting sensory cues make a behavioral choice between competing alternatives through integration of the sensory cues. Here, we performed a genetic screen to identify genes important for the sensory integration of two conflicting cues, the attractive odorant diacetyl and the aversive stimulus Cu2+, and found that the membrane-bound guanylyl cyclase GCY-28 and the receptor tyrosine kinase SCD-2 regulate the behavioral choice between these alternatives inCaenorhabditis elegans. Thegcy-28mutants andscd-2mutants show an abnormal bias in the behavioral choice between the cues, although their responses to each individual cue are similar to those in wild-type animals. Mutants in a gene encoding a cyclic nucleotide gated ion channel,cng-1, also exhibit the defect in sensory integration. Molecular genetic analyses suggested that GCY-28 and SCD-2 regulate sensory integration in AIA interneurons, where the conflicting sensory cues may converge. Genetic ablation or hyperpolarization of AIA interneurons showed nearly the same phenotype asgcy-28orscd-2mutants in the sensory integration, although this did not affect the sensory response to each individual cue. Ingcy-28orscd-2mutants, activation of AIA interneurons is sufficient to restore normal sensory integration. These results suggest that the activity of AIA interneurons regulates the behavioral choice between the alternatives. We propose that GCY-28 and SCD-2 regulate sensory integration by modulating the activity of AIA interneurons.
Theta Phase Precession in Rat Ventral Striatum Links Place and Reward Information
Authors: van der Meer Matthijs A. A. , Redish A. David
Published: February 2011

A functional interaction between the hippocampal formation and the ventral striatum is thought to contribute to the learning and expression of associations between places and rewards. However, the mechanism of how such associations may be learned and used is currently unknown. We recorded neural ensembles and local field potentials from the ventral striatum and CA1 simultaneously as rats ran a modified T-maze. Theta-modulated cells in ventral striatum almost invariably showed firing phase precession relative to the hippocampal theta rhythm. Across the population of ventral striatal cells, phase precession was preferentially associated with an anticipatory ramping of activity up to the reward sites. In contrast, CA1 population activity and phase precession were distributed more uniformly. Ventral striatal phase precession was stronger to hippocampal than ventral striatal theta and was accompanied by increased theta coherence with hippocampus, suggesting that this effect is hippocampally derived. These results suggest that the firing phase of ventral striatal neurons contains motivationally relevant information and that phase precession serves to bind hippocampal place representations to ventral striatal representations of reward.
Theta Phase Classification of Interneurons in the Hippocampal Formation of Freely Moving Rats
Authors: Czurkó András , Huxter John , Li Yu , Hangya Balázs , Muller Robert U.
Published: February 2011

Earlier work on freely moving rats classified neurons in Ammon's horn as pyramidal cells (including place cells) or interneurons (previously called “theta cells”) based on temporal discharge correlates and waveform configurations, but the anatomical and biochemical diversity of interneurons suggests they may have other distinguishing characteristics. To explore this possibility, we made extracellular recordings as rats foraged for food in an open space, used accepted criteria to identify interneurons, and found two additional categorization methods. First, interneurons were separated into theta-modulated and theta-independent groups using spike autocorrelograms. Second, theta-modulated interneurons were further separated into four groups by the phase of the ∼8 Hz theta rhythm at which firing was most rapid. These phase groups resemble the four phase peak groups of five anatomically identified interneuron types (two with the same preferred phase) recorded during the slow (∼4 Hz) theta rhythm in urethane-anesthetized rats. We suggest that the similar number of peak phase groups in walking rats and urethane-anesthetized rats and the partial agreement between peak phase values reflect a similar organization of theta rhythm in both states, so that the discharge properties of anatomically identified interneurons can be described in freely moving rats. Interestingly, the average spatial firing precision of the interneuron classes does not differ significantly, suggesting that the strong location-specific firing of place cells may be due to segregated high- and low-precision interneuron ensembles rather than to one or more dedicated high-precision classes.
Olfactory Marker Protein Is Critical for Functional Maturation of Olfactory Sensory Neurons and Development of Mother Preference
Authors: Lee Anderson C. , He Jiwei , Ma Minghong
Published: February 2011

Survival of many altricial animals critically depends on the sense of smell. Curiously, the olfactory system is rather immature at birth and undergoes a maturation process, which is poorly understood. Using patch-clamp technique on mouse olfactory sensory neurons (OSNs) with a defined odorant receptor, we demonstrate that OSNs exhibit functional maturation during the first month of postnatal life by developing faster response kinetics, higher sensitivity, and most intriguingly, higher selectivity. OSNs expressing mouse odorant receptor 23 (MOR23) are relatively broadly tuned in neonates and become selective detectors for the cognate odorant within 2 weeks. Remarkably, these changes are prevented by genetic ablation of olfactory marker protein (OMP), which is exclusively expressed in mature OSNs. Biochemical and pharmacological evidence suggests that alteration in odorant-induced phosphorylation of signaling proteins underlie some of theOMP−/−phenotypes. Furthermore, in a novel behavioral assay in which the mouse pups are given a choice between the biological mother and another unfamiliar lactating female, wild-type pups prefer the biological mother, while OMP knock-out pups fail to show preference. These results reveal that OSNs undergo an OMP-dependent functional maturation process that coincides with early development of the smell function, which is essential for pups to form preference for their mother.
How Thalamus Connects to Spiny Stellate Cells in the Cat's Visual Cortex
Authors: da Costa Nuno Maçarico , Martin Kevan A. C.
Published: February 2011

In the cat's visual cortex, the responses of simple cells seem to be totally determined by their thalamic input, yet only a few percent of the excitatory synapses in layer 4 arise from the thalamus. To resolve this discrepancy between structure and function, we used correlated light and electron microscopy to search individual spiny stellate cells (simple cells) for possible structural features that would explain the biophysical efficacy of the thalamic input, such as synaptic location on dendrites, size of postsynaptic densities, and postsynaptic targets. We find that thalamic axons form a small number of synapses with the spiny stellates (188 on average), that the median size of the synapses is slightly larger than that of other synapses on the dendrites of spiny stellates, that they are not located particularly proximal to the soma, and that they do not cluster on the dendrites. These findings point to alternative mechanisms, such as synchronous activation of the sparse thalamic synapses to boost the efficacy of the thalamic input. The results also support the idea that the thalamic input does not by itself determine the cortical response of spiny stellate cells, allowing the cortical microcircuit to amplify and modulate its response according to the particular context and computation being performed.
Activation of CREB in the Nucleus Accumbens Shell Produces Anhedonia and Resistance to Extinction of Fear in Rats
Authors: Muschamp John W. , Van't Veer Ashlee , Parsegian Aram , Gallo Miranda S. , Chen Melissa , Neve Rachael L. , Meloni Edward G. , Carlezon William A.
Published: February 2011

Stress triggers psychiatric conditions including depressive and anxiety disorders. The mechanisms by which stress produces persistent changes in behavior are not fully understood. Here we show in rats that stress (footshock) activates the transcription factor cAMP response element binding protein (CREB) within the nucleus accumbens shell (NAS), a brain area involved in encoding reward and aversion. To examine the behavioral significance of altered CREB function in the NAS, we used viral vectors to elevate or disrupt CREB in this region. Elevated CREB produced increases in intracranial self-stimulation thresholds, a depressive-like sign reflecting anhedonia (decreased sensitivity to reward), whereas disruption of CREB function by expression of a dominant-negative CREB had the opposite effect. To determine whether neuroadaptations that produce anhedonia subsequently affect vulnerability to stress-induced behavioral adaptations, we subjected rats with altered CREB function in the NAS to fear conditioning. Although neither elevation nor disruption of CREB function altered the development of conditioned fear, elevation of CREB impaired extinction of conditioned fear. To mimic downstream effects of CREB activation on expression of the opioid peptide dynorphin, we microinjected the κ-opioid receptor (KOR) agonist U50,488 directly into the NAS. KOR stimulation produced anhedonia but had no effect on expression or extinction of conditioned fear. These findings demonstrate that activation of CREB in the NAS produces multiple behavioral signs (anhedonia, impaired extinction) characteristic of experience-dependent psychiatric conditions such as posttraumatic stress disorder. Although CREB activation is a common trigger, expression of these individual signs appears to involve divergent downstream mechanisms.
Effective Pulmonary Artery Perfusion Mode during Cardiopulmonary Bypass
Authors: Zhang Renteng , Wang Zengwei , Wang Huishan , Song Hengchang , Zhang Nanbin , Fang Minhua
Published: February 2011

Aim: Reducing lung injury during cardiopulmonary bypass (CPB) is important for patients' recovery. The present study was designed to research convenient and effective pulmonary artery perfusion mode during CPB in an animal model.Methods: Twelve healthy mongrel dogs were randomly divided into 2 groups: a control group and a perfusion group designed to simulate clinical CPB-induced lung injury. During CPB, pulmonary artery perfusion with modified lowpotassium dextran (LPD) solution was performed immediately after the initiation of ischemia and before reperfusion for 3 to 4 minutes each time, with pressure maintained at 15 to 20 mmHg; animals in the control group were not perfused. After pulmonary reperfusion, the changes in pulmonary function and tissue biochemical data were determined.Results: Compared with the control group, lung compliance, oxygenation, and vascular resistance after reperfusion were significantly improved in the perfusion group. The malonaldehyde concentration, neutrophil sequestration ratio, and tissue water content also decreased significantly in the perfusion group.Conclusion: The pulmonary artery perfusion mode used in this experiment could relieve CPB-induced lung injury effectively. Improving cellular tolerance to hypoxia and decreasing inflammatory reaction may be the important mechanisms. Moreover, this mode is convenient and does not interfere with the intended operations, which is promising for clinical use.