bluuebunny/crossref_metadata_2025 huggingface dataset:
A Bound on Modeling Error in Observable Operator Models and an Associated Learning Algorithm
Authors: Zhao Ming-Jie , Jaeger Herbert , Thon Michael
Published: June 2009

Observable operator models (OOMs) generalize hidden Markov models (HMMs) and can be represented in a structurally similar matrix formalism. The mathematical theory of OOMs gives rise to a family of constructive, fast, and asymptotically correct learning algorithms, whose statistical efficiency, however, depends crucially on the optimization of two auxiliary transformation matrices. This optimization task is nontrivial; indeed, even formulating computationally accessible optimality criteria is not easy. Here we derive how a bound on the modeling error of an OOM can be expressed in terms of these auxiliary matrices, which in turn yields an optimization procedure for them and finally affords us with a complete learning algorithm: the error-controlling algorithm. Models learned by this algorithm have an assured error bound on their parameters. The performance of this algorithm is illuminated by comparisons with two types of HMMs trained by the expectation-maximization algorithm, with the efficiency-sharpening algorithm, another recently found learning algorithm for OOMs, and with predictive state representations (Littman & Sutton, 2001 ) trained by methods representing the state of the art in that field.
Sequential Monte Carlo Point-Process Estimation of Kinematics from Neural Spiking Activity for Brain-Machine Interfaces
Authors: Wang Yiwen , Paiva António R. C. , Príncipe José C. , Sanchez Justin C.
Published: June 2009

Many decoding algorithms for brain machine interfaces' (BMIs) estimate hand movement from binned spike rates, which do not fully exploit the resolution contained in spike timing and may exclude rich neural dynamics from the modeling. More recently, an adaptive filtering method based on a Bayesian approach to reconstruct the neural state from the observed spike times has been proposed. However, it assumes and propagates a gaussian distributed state posterior density, which in general is too restrictive. We have also proposed a sequential Monte Carlo estimation methodology to reconstruct the kinematic states directly from the multichannel spike trains. This letter presents a systematic testing of this algorithm in a simulated neural spike train decoding experiment and then in BMI data. Compared to a point-process adaptive filtering algorithm with a linear observation model and a gaussian approximation (the counterpart for point processes of the Kalman filter), our sequential Monte Carlo estimation methodology exploits a detailed encoding model (tuning function) derived for each neuron from training data. However, this added complexity is translated into higher performance with real data. To deal with the intrinsic spike randomness in online modeling, several synthetic spike trains are generated from the intensity function estimated from the neurons and utilized as extra model inputs in an attempt to decrease the variance in the kinematic predictions. The performance of the sequential Monte Carlo estimation methodology augmented with this synthetic spike input provides improved reconstruction, which raises interesting questions and helps explain the overall modeling requirements better.
Computation with Spikes in a Winner-Take-All Network
Authors: Oster Matthias , Douglas Rodney , Liu Shih-Chii
Published: June 2009

The winner-take-all (WTA) computation in networks of recurrently connected neurons is an important decision element of many models of cortical processing. However, analytical studies of the WTA performance in recurrent networks have generally addressed rate-based models. Very few have addressed networks of spiking neurons, which are relevant for understanding the biological networks themselves and also for the development of neuromorphic electronic neurons that commmunicate by action potential like address-events. Here, we make steps in that direction by using a simplified Markov model of the spiking network to examine analytically the ability of a spike-based WTA network to discriminate the statistics of inputs ranging from stationary regular to nonstationary Poisson events. Our work extends previous theoretical results showing that a WTA recurrent network receiving regular spike inputs can select the correct winner within one interspike interval. We show first for the case of spike rate inputs that input discrimination and the effects of self-excitation and inhibition on this discrimination are consistent with results obtained from the standard rate-based WTA models. We also extend this discrimination analysis of spiking WTAs to nonstationary inputs with time-varying spike rates resembling statistics of real-world sensory stimuli. We conclude that spiking WTAs are consistent with their continuous counterparts for steady-state inputs, but they also exhibit high discrimination performance with nonstationary inputs.
Sequential Effects in Two-Choice Reaction Time Tasks: Decomposition and Synthesis of Mechanisms
Authors: Gao Juan , Wong-Lin KongFatt , Holmes Philip , Simen Patrick , Cohen Jonathan D.
Published: June 2009

Performance on serial tasks is influenced by first- and higher-order sequential effects, respectively, due to the immediately previous and earlier trials. As response-to-stimulus interval (RSI) increases, the pattern of reaction times transits from a benefit-only mode, traditionally ascribed to automatic facilitation (AF), to a cost-benefit mode, due to strategic expectancy (SE). To illuminate the sources of such effects, we develop a connectionist network of two mutually inhibiting neural decision units subject to feedback from previous trials. A study of separate biasing mechanisms shows that residual decision unit activity can lead to only first-order AF, but higher-order AF can result from strategic priming mediated by conflict monitoring, which we instantiate in two distinct versions. A further mechanism mediates expectation-related biases that grow during RSI toward saturation levels determined by weighted repetition (or alternation) sequence lengths. Equipped with these mechanisms, the network, consistent with known neurophysiology, accounts for several sets of behavioral data over a wide range of RSIs. The results also suggest that practice speeds up all the mechanisms rather than adjusting their relative strengths.
Automatic Spike Sorting Using Tuning Information
Authors: Ventura Valérie
Published: June 2009

Current spike sorting methods focus on clustering neurons' characteristic spike waveforms. The resulting spike-sorted data are typically used to estimate how covariates of interest modulate the firing rates of neurons. However, when these covariates do modulate the firing rates, they provide information about spikes' identities, which thus far have been ignored for the purpose of spike sorting. This letter describes a novel approach to spike sorting, which incorporates both waveform information and tuning information obtained from the modulation of firing rates. Because it efficiently uses all the available information, this spike sorter yields lower spike misclassification rates than traditional automatic spike sorters. This theoretical result is verified empirically on several examples. The proposed method does not require additional assumptions; only its implementation is different. It essentially consists of performing spike sorting and tuning estimation simultaneously rather than sequentially, as is currently done. We used an expectation-maximization maximum likelihood algorithm to implement the new spike sorter. We present the general form of this algorithm and provide a detailed implementable version under the assumptions that neurons are independent and spike according to Poisson processes. Finally, we uncover a systematic flaw of spike sorting based on waveform information only.
Aristotle on the Subject Matter of Geometry
Authors: Pettigrew Richard
Published: June 2009

I offer a new interpretation of Aristotle's philosophy of geometry, which he presents in greatest detail in Metaphysics M 3. On my interpretation, Aristotle holds that the points, lines, planes, and solids of geometry belong to the sensible realm, but not in a straightforward way. Rather, by considering Aristotle's second attempt to solve Zeno's Runner Paradox in Book VIII of the Physics, I explain how such objects exist in the sensibles in a special way. I conclude by considering the passages that lead Jonathan Lear to his fictionalist reading of Met. M3,1 and I argue that Aristotle is here describing useful heuristics for the teaching of geometry; he is not pronouncing on the meaning of mathematical talk.
'God Doesn't Care': The Contradictions of Christian Zionism
Authors: Abraham Ibrahim , Boer Roland
Published: June 2009

Defining Christian Zionism as theological support for Israel as a Zionist state, this article analyses four contradictions in such a theology. Firstly, although Christian Zionism insists it is purely theological, not political, this separation is impossible. Secondly, mainstream Zionist use of Christian Zionism to influence US foreign policy is misguided, since Christian Zionists wish to convert or annihilate all Jews. Thirdly, Christian Zionism is anti-Semitic, wishing to eliminate all non-converted Jews (and Arabs). Finally, since Christian Zionists read the Old and New Testaments in a 'literal' fashion, they resort to the violence of Armageddon to resolve their theological contradictions.
Factors, Process and Outcomes of Recovery From Psychiatric Disability: the Unity Model
Authors: Song Li-Yu , Shih Chaiw-Yi
Published: June 2009

Background: Despite the fruitful findings on related issues of recovery in the West, some researchers have called for more studies on the factors that facilitate recovery and international literature on recovery to be made available. Moreover, to date, a united model that integrates outcome, component process and contextual factors of recovery has not yet been developed. Thus, this study explored the recovery experiences of persons with psychiatric disabilities (hereinafter called consumers) in Taiwan and extracted the key facilitators for developing a preliminary unity theory of recovery.

Material: In-depth qualitative interviews of 15 consumers in recovery and their caregivers were held. Over a research period of two years, consumers were interviewed twice. The dialogue of each interview was transcribed into text and a narrative summary of the storyline for each participant was also prepared.

Discussion: For most consumers, the journey of recovery was an incremental process of progress, yet few of them mentioned a turning point and its significant change on their life. Regaining social roles seemed to be a necessary but not sufficient outcome indicator for recovery. While symptom remission, mental strength and parental support were the cornerstones for recovery, the treatment model and professionals got the credit for it too.

Conclusion: The recovery process occurs within a complex context of various stages and multi-facilitators. The forces of three cornerstones, essential components and contextual facilitators all influx into the river of recovery and emerge as one united mechanism that supports the consumer's spiral progress through the journey of striving for autonomy.
Effects of Obesity and Obesity-Induced Stress On Depressive Symptoms in Korean Elementary School Children
Authors: Park Chul-Min , Kim Moon-Doo , Hong Seong-Chul , Kim Yeol , Hyun Mi-Youl , Kwak Young-Sook , Lee Chang-In , Park Min-Jeong , Jang Yun-Hee , Moon Ji-Hyun , Seok Eun-Mi , Song Young-Ja , Hyeon Ju Kim
Published: June 2009

Background: Obesity is becoming prevalent in Korean children. Because body image is becoming increasingly important, it is likely that obesity-induced stress has a significant effect on childhood depression.

Aims: To examine the correlation between obesity-induced stress and depressive symptoms in Korean elementary school students.

Methods: The study participants were 2,305 elementary school children and their parents in the districts of Jeju-si, Seogwipo-si, Namjeju-gun and Bukjeju-gun on Jeju Island, Korea, who completed questionnaires involving demographic information, an obesity-induced stress scale and the Korean form of Kovacs' Children's Depression Inventory (CDI) from September to December 2006.

Results: After controlling for significant independent variables that are wellknown correlates of depressive symptoms in children (e.g. age, gender, residence, family monthly income, obesity status of both parents, family history of chronic illness, and time spent with mother), obesity-induced stress had an odds ratio of 1.128 (95% CI 1.111—1.146).

Conclusions: Reducing the prevalence of depressive symptoms in elementary school children in Jeju Island will require special attention, particularly the development of coping strategies to resolve obesity-induced stress in various areas including school, family and society.
International Migration of Partner, Autonomy and Depressive Symptoms Among Women From a Mexican Rural Area
Authors: Bojorquez Ietza , Salgado de Snyder Nelly , Casique Irene
Published: June 2009

Background: The emigration of Mexicans to the USA has increased in the last decades, and little is known about the effect of this on the mental health of those who stay behind.

Aims: To evaluate the association of emigration of husband and depressive symptoms (DS) among women who stay in Mexico. We also tested the hypothesis that the husband's migration would increase the woman's autonomy, which in turn would decre se DS.

Methods: A survey was conducted in a rural area in Mexico. Participants ( n = 418) were selected through probabilistic sampling in three stages: localities, households and individuals. DS were evaluated using the Centre for Epidemiological Studies-Depression (CES-D) scale.

Results: Having a partner in the USA was associated with higher odds of scoring above the cut-off point in CES-D (OR 3.77, 95% CI 1.92—7.43). Economic autonomy was also associated with DS (OR 1.45, 95% CI 1.04—2.02).

Conclusion: Migration of husband was associated with DS among women. The construct of autonomy and its operational definition should be further explored.
A Literacy Tutoring Experience for Prospective Special Educators and Struggling Second Graders
Authors: Spear-Swerling Louise
Published: June 2009

This study examined the learning of teacher candidates taking a language arts course in a special-educator preparation program and that of the second graders they tutored in a supervised field component of the course. Teacher candidates’ knowledge of literacy instruction was assessed using five knowledge tasks; children were assessed on several measures of basic reading and spelling skills as well as on their knowledge of phonics concepts such as syllable types. Teacher candidates generally had inaccurate perceptions of their knowledge at pretest, but their knowledge improved significantly on all tasks after course instruction. Tutored children improved significantly from pre- to posttest on all assessments. The study suggests that carefully designed literacy coursework with field experiences can benefit both prospective special educators and struggling readers.
Reckless States and Realism
Authors: Mearsheimer John J.
Published: June 2009

Kenneth Waltz opted to reject the rational actor assumption in developing his theory of international politics. That choice, I argue in this article, creates three problems for his theory. First, it means that it is unsuited for explaining state behavior, which means it is of limited utility for explaining the workings of the international system. Second, Waltz's claim that his theory is well suited to explaining international outcomes — as opposed to state behavior — is unconvincing. Those outcomes are heavily influenced by the actions of the great powers, but if his theory cannot predict their behavior, it is unlikely to reliably predict the outcomes of their behavior. Third, Waltz's assumption that states often behave recklessly leads to a more competitive world than described in his theory. I conclude with the suggestion that the theory's greatest virtue is its normative value — its ability to explain how the world should work, not how it works.
Woman, the State, and War
Authors: Elshtain Jean Bethke
Published: June 2009

Does `gender' as a category of analysis or as a central feature of a logic of explanation alter in significant ways Kenneth Waltz's famous `levels of analysis' as developed in his classic, Man, the State, and War? One overriding claim of feminist international relations has been that `gender' alters all levels of analysis; thus, changing `man' to `woman' in the formulation `man, the state, and war' significantly transforms our understanding of international relations. I evaluate this claim critically by assessing the adequacy of feminist formulations on each of Waltz's levels of analysis and, further, by unpacking Waltz's own understanding of these levels. I conclude that Waltz remains enormously helpful in deconstructing reductionist accounts, especially on the `first level' of analysis, but that his own account is problematic insofar as it insists on a `structural analysis' sundered from his levels 1 and 2, namely, wars flow from human nature or, alternatively, from the domestic ordering of states. I point out that Waltz himself leaves some `wiggle room' in his book that permits one to `plug in' features of the first two levels of analysis that are critical to understanding the structural level. In other words, all three levels must be in play if one is to craft a compelling explanatory framework.
Methylphenidate Has Positive Hypocholesterolemic and Hypotriglyceridemic Effects: New Data
Authors: Charach Gideon , Kaysar Nehemia , Grosskopf Itamar , Rabinovich Alexander , Weintraub Moshe
Published: June 2009

Many psychotropic drugs may affect plasma lipids profile and their metabolism, with carbamazepine being the best known among them. Methylphenidate is a piperidine derivative structurally related to amphetamines and acts as a central nervous system stimulant. Its effect on lipid metabolism has not been investigated. The authors evaluated how methylphenidate affects the lipid profile in the plasma of patients diagnosed as having attention‐deficit hyperactivity disorder (ADHD). All consecutive patients undergoing treatment for ADHD at the Adolescent Psychiatric Clinic (2003–2007) were enrolled. Blood samples for total cholesterol, low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein cholesterol (HDL‐C), triglycerides, apolipoprotein A, apolipoprotein B, and lipoprotein (a) (Lp(a)) were collected before starting treatment and after 3 months of continuous treatment. Forty‐two patients (22 men), median age 16, participated. The median total cholesterol count decreased by 9 mg/dL (P < .0002), LDL‐C decreased by 5.0 mg/dL (P < .016), and triglycerides decreased by 8.0 mg/dL (P < .016). Changes in the levels of HDL‐C, apolipoprotein A, and apolipoprotein B were nonsignificant, and Lp(a) levels decreased by 2.0 mg/dL (P < .0007). Methylphenidate improves the lipid profile by decreasing total cholesterol, triglycerides, LDL‐C, and Lp(a).
Pharmacokinetics, Safety, and Tolerability of Doripenem After 0.5‐, 1‐, and 4‐Hour Infusions in Healthy Volunteers
Authors: Cirillo Iolanda , Vaccaro Nicole , Turner Kenneth , Solanki Bhavna , Natarajan Jaya , Redman Rebecca
Published: June 2009

The pharmacokinetics, safety, and tolerability of doripenem in healthy subjects were evaluated in 2 studies. Study 1 was a double‐blind, randomized, placebo‐controlled dose‐escalation study in which doripenem was administered for 7 days by infusion over 30 minutes (500 mg) or 1 hour (1000 mg). Study 2 was an open‐label, randomized, 3‐way crossover study in which each subject received a single dose of each of the following doripenem treatments on separate occasions: 500 mg infused over 1 hour, 500 mg infused over 4 hours, and 1000 mg infused over 4 hours. Doripenem exhibited linear pharmacokinetics with concordance between the studies for pharmacokinetic parameters. Doripenem did not accumulate with repeated dosing over 7 days. The area under the plasma concentration‐time curve (AUC) for doripenem 500 mg infused over 1 hour versus 4 hours was bioequivalent, and the AUC and Cmax increased proportionally with dose for the 500‐ and 1000‐mg doses administered over 4 hours. These results, along with the stability profile of doripenem, support its use as a prolonged infusion. All regimens of doripenem were safe and well tolerated.
New Reclaiming Process of Thermoset Polyurethane Foam and Blending with Polyamide-12 and Thermoplastic Polyurethane
Authors: Gonella L.B. , Zattera A.J. , Zeni M. , Oliveira R.V.B. , Canto L.B.
Published: June 2009

A new method to reclaim thermoset polyurethane (PU) foam by thermo-mechanical degradation using a batch Drais mixer was investigated, and the performance of reclaimed PU in blends with polyamide-12 (PA-12) or thermoplastic polyurethane (TPU) was studied. The reclamation method used disrupts the crosslinked structure of PU, decreasing its degree of crosslinking, which was confirmed through the determination of gel content, and by DSC, TGA and FTIR analyses. Under severe reclaiming conditions, the reclaimed PU was found to retain about half of its initial gel content. The blends of original PU and reclaimed PU (PU-r) with PA-12 and with TPU were prepared using a twin-screw extruder and were characterized with respect to their mechanical properties. For the PA-12/PU 75/25 blend, the addition of PU was observed to toughen the PA-12 matrix whereas for TPU/PU blends, the rubber-like behavior of TPU was not significantly affected by the presence of PU. The remarkable mechanical behavior of the blends attests to the high compatibility of PU-r with both PA-12 and TPU. This may be due to the physical interactions between the blend components, leading to high interfacial adhesion. The reclamation of PU-r before its melt processing with PA-12 or TPU was found to improve the processability during the injection molding of the PA-12/PU-r and TPU/PU-r blends.
Osteotomies about the Knee for Tibiofemoral Malalignment in the Athletic Patient
Authors: Gardiner Aaron , Gutiérrez Sevilla Gerardo R. , Steiner Mark E. , Richmond John C.
Published: June 2009

Osteotomies have a role in the active patient with degenerative joint disease of the medial or lateral knee who, for reasons of age or activity level, is not yet a good candidate for prosthetic arthroplasty. Recognition and treatment of malalignment associated with ligamentous instability is essential if long-term good outcomes are to be expected from ligamentous reconstruction. Also, treatment of concomitant malalignment and the unloading of the operative site is now recognized as an important adjunct to any cartilage-preserving surgery. This review examines the use of osteotomies about the knee in the athletic patient. Indications, contraindications, preoperative planning, surgical techniques, and complications are reviewed.
Analysis of Mechanical Behavior of Phenol Formaldehyde Matrix Composites Using Flax-g-Poly (MMA) as Reinforcing Materials
Authors: Chauhan S.R. , Patnaik Amar , Kaith B.S. , Satapathy Alok , Dwivedy Maheshwar
Published: June 2009

This article deals with synthesis of phenol-formaldehyde resin and preparation of phenol-formaldehyde matrix based composites using raw flax and flax graft co-polymer as reinforcing agent. Prior to using the graft co-polymer as a reinforcing material, its strength vis-à-vis that of raw flax are studied in this study. Composites thus prepared are subjected to different mechanical tests such as wear, tensile, and compression tests etc. The graft co-polymers are characterized by using FTIR and scanning electron microscope (SEM). It has been observed that the composites refined with raw flax are more wear resistant as compared to the graft copolymer refined composites. In the case of the tensile test, composites reinforced with grafted flax showed more extension as compared to that of raw flax reinforcement, but required less loading at break point. However, composites with raw flax reinforcement initially showed more compression as compared to reinforcement with grafted fiber but at higher applied load grafted fiber reinforcement is found to show more compressive strength. Moreover, water repellency property of the fiber could be improved on grafting with methyl methacrylate (MMA) whereas the raw flax is found to be more vulnerable to water.
SIF for Double- and Single-sided Composite Repair in Mode I and Mixed Mode
Authors: Bachir Bouiadjra B. , Fekirini H. , Belhouari M. , Serier B. , Benguediab M. , Ouinas D.
Published: June 2009

In this study, the finite element is used to analyze and compare the performances of the double- and single-sided composite repair in aircraft structures in mode I and mixed mode. The stress intensity factors in modes I and II at the crack tip are computed to perform the objective of the study. The effects of the different parameters of repair such as adhesive and patch properties on the SIF variation were highlighted. The obtained results show that the adhesive properties must be optimized in order to increase the advantage of the double patch and to avoid adhesive failure. The patch properties have a significant effect on the beneficial effects of the double symmetric patch.
New Directions in Public Administration
Authors: Bourgon Jocelyne
Published: June 2009

Governments serve as a vehicle through which citizens, communities and societies express their values and preferences (Bourgon, 2007). Some of these values and preferences remain constant; while others change as societies confront new situations and evolve. Periodically, new values surface whose energy transforms the role of government and the practice of public administration. Reflecting back on the last three decades, we can see how public administrators around the world embarked on a journey of experimentation and innovation in response to changing circumstances and public expectations (Bourgon, 2008a). The nature and pace of change has been astonishing. The theme of the conference is `New Directions in the Study and Practice of Public Administration'. In addressing this theme, I will argue that the search for new directions in research and the practice of public administration should relate to the search for a new balance in the role of government.
Exploring the Use of DNA Evidence in Homicide Investigations
Authors: Schroeder David A. , White Michael D.
Published: June 2009

Since the 1960s there has been a consistent gradual decline in national homicide clearance rates and the trend continued throughout the 1990s and into the 21st century, despite the development of DNA evidence. Although the media portrays DNA testing as an investigative “super weapon” for police, there is little empirical research examining its actual use by detectives or its impact on case clearance. This article examines New York Police Department (NYPD) case files for Manhattan homicides between 1996 and 2003 to investigate how often detectives used DNA evidence in the course of their investigations, as well as how its use influenced the likelihood of case clearance. Results suggest that DNA evidence was rarely used by NYPD detectives and that it was not related to case clearance. These findings suggest that NYPD detectives used DNA evidence as a “tool of last resort,” relying on it only when all other investigative means had been exhausted. The authors conclude that the explanation for these findings is complex and that the diffusion framework may be helpful in understanding detectives’ use of DNA evidence in New York and elsewhere.
Analytical Modeling of Composite Sandwich Panels under Blast Loads
Authors: Hoo Fatt Michelle S. , Palla Leelaprasad
Published: June 2009

Analytical solutions were derived for the transient response and damage initiation of a foam-core composite sandwich panel subjected to blast loading. The panel response was modeled in two consecutive phases: (1) a through-thickness wave propagation phase leading to permanent core crushing deformations and (2) a transverse shear wave propagation phase resulting in global panel deflections. The predicted transient deformation of a sandwich panel consisting of E-glass vinyl ester facesheets and H100 PVC foam core compared well with ABAQUS predictions. Analytical predictions of the critical impulse for damage initiation in several foam sandwich panels also compared well with ABAQUS predictions.
Design Analysis of the Mixed Mode Bending Sandwich Specimen
Authors: Quispitupa Amilcar , Berggreen Christian , Carlsson Leif A.
Published: June 2009

A design analysis of the mixed mode bending (MMB) sandwich specimen for face—core interface fracture characterization is presented. An analysis of the competing failure modes in the foam cored sandwich specimens is performed in order to achieve face—core debond fracture prior to other failure modes. The analysis facilitates selection of the appropriate geometry for the MMB sandwich specimen to promote debond failure. An experimental study is performed using MMB sandwich specimens with a H100 PVC foam core and E-glass—polyester faces. The results reveal that debond propagation is successfully achieved for the chosen geometries and mixed mode loading conditions.
Impact Damage and Energy-absorbing Characteristics and Residual In-plane Compressive Strength of Honeycomb Sandwich Panels
Authors: Zhou G. , Hill M.D.
Published: June 2009

An experimental study of the in-plane compressive behavior of both aluminium and nomex composite sandwich panels with 8 ply carbon/epoxy skins was conducted. All sandwich panels were impact-damaged with a range of impact energies from 1 to 55 J. Dominant damage mechanisms were found to be core crushing, skin delamination, and fracture with the former two absorbing most of the impact energy. While the intact panels failed in region close to one loaded end, all the impact-damaged nomex panels failed around the mid-section region. Two thirds of the aluminium panels also failed in the mid-section region and one third failed in the loaded end region. The presence of the core played a unique role in in-plane compression with a substantial stabilizing support to the skins, which counteracted the deleterious effect of impact damage. The in-plane compressive behavior has shown the combined effects of impact damage and the core in a complex manner.
Impacts of a historical film on the destination image of South America
Authors: Shani Amir , Wang Youcheng , Hudson Simon , Gil Sergio Moreno
Published: June 2009

This study examines the destination image of South America among young North American students through the lens of a historic movie with controversial content. The results of the study reveal that South America is perceived as an affordable ecotourism destination, with emphasis on the nature, cultural and heritage attributes of the region. It is also perceived as less developed, secured and westernized than their home environment. It is found that watching the movie has not dramatically changed the destination image of South America, but rather strengthened previous perceptions. Nevertheless, an increasing desire to visit South America is evidenced among the participants. The findings of the study call for more critical and cautious analysis of the phenomenon of film tourism. In addition, it also suggests that with certain conditions even films with controversial plot may contribute to tourism industry of a destination.
Basic Science Review: Vascular Distensibility as a Predictive Tool in the Management of Small Asymptomatic Abdominal Aortic Aneurysms
Authors: Hoegh Annette , Lindholt Jes S.
Published: June 2009

Background: This study investigates whether baseline aortic wall distensibility serves as a supplemental bio-marker for AAA progression and need for later repair. Methods: In 1998, 61 males with a small asymptomatic AAAs had a baseline measurement of elasticity and stiffness, using an echo-tracking ultrasound system (Diamove). The cohort was followed till 2005 concerning Dmax, expansion rate, operations for AAA, hospitalisation do to cardiovascular disease and death. Results: During follow-up, 49% died, and 45.9% were hospitalised do to cardiovascular disease, compared to Dmax, Ep and b no significant associations were found. Elasticity correlated moderately to annual expansion rate and Dmax. Good correlation was found between annual expansion rate and Dmax. ROC-curve analysis showed that elasticity, stiffness and Dmax all tended to predict future need for AAA-repair. Conclusion: Baseline aortic wall distensibility may provide an additional parameter for AAA to optimize the indication and time for elective repair.
Sonographic Imaging of the Fetal Hard Palate During the Second-Trimester Pregnancy Scan
Authors: Tonni Gabriele , Ventura Alessandro , Centini Giovanni , Rosignoli Lucia
Published: June 2009

Cleft lip and cleft palate are among the more common congenital abnormalities, representing the fourth most common birth defect in the United States, with an incidence of 1 in 700 live births. The study of fetal secondary palate has reached new potential due to new 3D applications— namely, tomographic sonography imaging and volume contrast imaging (VCI). The aim of this review is to describe the 3D sonographic setting for a systematic study of the fetal secondary palate during second-trimester pregnancy. Sonographers can easily achieve appropriate training in 3D scanning of the fetal face under expert tutoring. The sonographic study of the fetal secondary palate should become an integral part of the second-trimester scan. Technically, the axial and coronal sections are those that better display the 3D reconstruction, especially when the fetus is facing the transducer (profile section). The use of static VCI may enhance tomographic sonography imaging of the fetal secondary palate and should therefore be integrated in this target examination.
Synthesis of sialoglycopolypeptide for potentially blocking influenza virus infection using a rat α2,6-sialyltransferase expressed in BmNPV bacmid-injected silkworm larvae
Authors: Ogata Makoto , Nakajima Makoto , Kato Tatsuya , Obara Takakiyo , Yagi Hirokazu , Kato Koichi , Usui Taichi , Park Enoch Y
Published: June 2009

Background

Sialic acid is a deoxy uronic acid with a skeleton of nine carbons which is mostly found on cell surface in animals. This sialic acid on cell surface performs various biological functions by acting as a receptor for microorganisms, viruses, toxins, and hormones; by masking receptors; and by regulating the immune system. In order to synthesize an artificial sialoglycoprotein, we developed a large-scale production of rat α2,6-sialyltransferase (ST6Gal1). The ST6Gal1 was expressed in fifth instar silkworm larval hemolymph using recombinant both cysteine protease- and chitinase-deficient Bombyx mori nucleopolyhedrovirus (BmNPV-CP
--Chi
-) bacmid. The expressed ST6Gal1 was purified, characterized and used for sialylation of asialoglycopolypeptide. We tested the inhibitory effect of the synthesized α2,6-sialoglycopolypeptide on hemagglutination by Sambucus nigra (SNA) lectin.

Results

FLAG-tagged recombinant ST6Gal1 was expressed efficiently and purified by precipitation with ammonium sulphate followed by affinity chromatography on an anti-FLAG M2 column, generating 2.2 mg purified fusion protein from only 11 silkworm larvae, with a recovery yield of 64%. The purified ST6Gal1 was characterized and its N-glycan patterns were found to be approximately paucimannosidic type by HPLC mapping method. Fluorescently-labelled N-acetyllactosamine (LacNAc) glycoside containing dansyl group was synthesized chemo-enzymatically as high-sensitivity acceptor substrate for ST6Gal1. The acceptor substrate specificity of the enzyme was similar to that of rat liver ST6Gal1. The fluorescent glycoside is useful as a substrate for a highly sensitive picomole assay of ST6Gal1. Asialoglycopolypeptide was regioselectively and quantitatively sialylated by catalytic reaction at the terminal Gal residue to obtain α2,6-sialoglycopolypeptide using ST6Gal1. The α2,6-sialoglycopolypeptide selectively inhibited hemagglutination induced by Sambucus nigra (SNA) lectin, showing about 780-fold higher affinity than the control fetuin. Asialoglycopolypeptide and γ-polyglutamic acid did not affect SNA lectin-mediated hemagglutination.

Conclusion

The recombinant ST6Gal1 from a silkworm expression system is useful for the sialylation of asialoglycopeptide. The sialylated glycoprotein is a valuable tool for investigating the molecular mechanisms of biological and physiological events, such as cell-cell recognition and viral entry during infection.
Characterization of the repertoire diversity of the Plasmodium falciparum stevor multigene family in laboratory and field isolates
Authors: Blythe Jane E , Niang Makhtar , Marsh Kevin , Holder Anthony A , Langhorne Jean , Preiser Peter R
Published: June 2009

Background

The evasion of host immune response by the human malaria parasite Plasmodium falciparum has been linked to expression of a range of variable antigens on the infected erythrocyte surface. Several genes are potentially involved in this process with the var, rif and stevor multigene families being the most likely candidates and coding for rapidly evolving proteins. The high sequence diversity of proteins encoded by these gene families may have evolved as an immune evasion strategy that enables the parasite to establish long lasting chronic infections. Previous findings have shown that the hypervariable region (HVR) of STEVOR has significant sequence diversity both within as well as across different P. falciparum lines. However, these studies did not address whether or not there are ancestral stevor that can be found in different parasites.

Methods

DNA and RNA sequences analysis as well as phylogenetic approaches were used to analyse the stevor sequence repertoire and diversity in laboratory lines and Kilifi (Kenya) fresh isolates.

Results

Conserved stevor genes were identified in different P. falciparum isolates from different global locations. Consistent with previous studies, the HVR of the stevor gene family was found to be highly divergent both within and between isolates. Importantly phylogenetic analysis shows some clustering of stevor sequences both within a single parasite clone as well as across different parasite isolates.

Conclusion

This indicates that the ancestral P. falciparum parasite genome already contained multiple stevor genes that have subsequently diversified further within the different P. falciparum populations. It also confirms that STEVOR is under strong selection pressure.
Sex-associated effect of CETP and LPL polymorphisms on postprandial lipids in familial hypercholesterolaemia
Authors: Anagnostopoulou Katherine K , Kolovou Genovefa D , Kostakou Peggy M , Mihas Constantinos , Hatzigeorgiou Georgios , Marvaki Christina , Degiannis Dimitrios , Mikhailidis Dimitri P , Cokkinos Dennis V
Published: June 2009

Background

This study assessed the gender-specific influence of the cholesteryl ester transfer protein (TaqIB, I405V) and lipoprotein lipase (S447X) polymorphisms on the response to an oral fat tolerance test in heterozygotes for familial hypercholesterolaemia.

Methods

We selected and genotyped 80 men and postmenopausal women heterozygous for familial hypercholesterolaemia (main group) as well as 11 healthy control subjects. Patients were subgrouped based on their response to oral fat tolerance test. The oral fat tolerance test was defined as pathological when postprandial triglyceride concentration was higher than the highest triglyceride concentration observed in healthy subjects (220 mg/dl) at any time (2, 4, 6 or 8 h).

Results

In the pathological subgroup, men had significantly higher incremental area under the curve after oral fat tolerance test than postmenopausal women. Furthermore, multivariate analysis revealed a gender association of TaqIB and I405V influence on postprandial lipaemia in this subgroup.

Conclusion

In conclusion, it seems that gender and TaqIB polymorphism of the cholesteryl ester transfer protein gene were both associated with the distribution of triglyceride values after oral fat tolerance test, only in subjects with a pathological response to oral fat tolerance test. Specifically, men carrying the B2 allele of the TaqIB polymorphism showed a higher postprandial triglyceride peak and a delayed return to basal values compared with women carrying B2. However, further investigations in larger populations are required to replicate and confirm these findings.
Ozone and cardiovascular injury
Authors: Srebot Vera , Gianicolo Emilio AL , Rainaldi Giuseppe , Trivella Maria Giovanna , Sicari Rosa
Published: June 2009

Air pollution is increasingly recognized as an important and modifiable determinant of cardiovascular diseases in urban communities. The potential detrimental effects are both acute and chronic having a strong impact on morbidity and mortality. The acute exposure to pollutants has been linked to adverse cardiovascular events such as myocardial infarction, heart failure and life-threatening arrhythmias. The long-terms effects are related to the lifetime risk of death from cardiac causes. The WHO estimates that air pollution is responsible for 3 million premature deaths each year. The evidence supporting these data is very strong nonetheless, epidemiologic and observational data have the main limitation of imprecise measurements. Moreover, the lack of clinical experimental models makes it difficult to demonstrate the individual risk. The other limitation is related to the lack of a clear mechanism explaining the effects of pollution on cardiovascular mortality. In the present review we will explore the epidemiological, clinical and experimental evidence of the effects of ozone on cardiovascular diseases.

The pathophysiologic consequences of air pollutant exposures have been extensively investigated in pulmonary systems, and it is clear that some of the major components of air pollution (e.g. ozone and particulate matter) can initiate and exacerbate lung disease in humans [1]. It is possible that pulmonary oxidant stress mediated by particulate matter and/or ozone (O3) exposure can result in downstream perturbations in the cardiovasculature, as the pulmonary and cardiovascular systems are intricately associated, and it is well documented that specific environmental toxins (such as tobacco smoke [2]) introduced through the lungs can initiate and/or accelerate cardiovascular disease development. Indeed, several epidemiologic studies have proved that there is an association between PM and O3 and the increased incidence of cardiovascular morbidity and mortality [3]. Most of the evidence comes from studies of ambient particles concentrations. However, in Europe and elsewhere, the air pollution profile has gradually changed toward a more pronounced photochemical component. Ozone is one of the most toxic components of the photochemical air pollution mixture. Indeed, the biological basis for these observations has not been elucidated.

In the present review, the role of ozone as chemical molecule will be firstly considered. Secondly, pathogenetic mechanisms connecting the atmospheric ozone level and cardiovascular pathology will be examined. Thirdly, the literature relating hospitalization frequency, morbidity and mortality due to cardiovascular causes and ozone concentration will be studied. The correlation between ozone level and occurrence of acute myocardial infarction will be eventually discussed.
Akt finds its new path to regulate cell cycle through modulating Skp2 activity and its destruction by APC/Cdh1
Authors: Gao Daming , Inuzuka Hiroyuki , Tseng Alan , Wei Wenyi
Published: June 2009

Skp2 over-expression has been observed in many human cancers. However, the mechanisms underlying elevated Skp2 expression have remained elusive. We recently reported that Akt1, but not Akt2, directly controls Skp2 stability by interfering with its association with APC/Cdh1. As a result, Skp2 degradation is protected in cancer cells with elevated Akt activity. This finding expands our knowledge of how specific kinase cascades influence proteolysis governed by APC/Cdh1 complexes. However, it awaits further investigation to elucidate whether the PI3K/Akt circuit affects other APC/Cdh1 substrates. Our results further strengthen the argument that different Akt isoforms might have distinct, even opposing functions in the regulation of cell growth or migration. In addition, we noticed that Ser72 is localized in a putative Nuclear Localization Sequence (NLS), and that phosphorylation of Ser72 disrupts the NLS and thus promotes Skp2 cytoplasmic translocation. This finding links elevated Akt activity with the observed cytoplasmic Skp2 staining in aggressive breast and prostate cancer patients. Furthermore, it provides the rationale for the development of specific Akt1 inhibitors as efficient anti-cancer therapeutic agents.
Epidermal wound healing in severe sepsis and septic shock in humans
Authors: Koskela Marjo , Gäddnäs Fiia , Ala-Kokko Tero I , Laurila Jouko J , Saarnio Juha , Oikarinen Aarne , Koivukangas Vesa
Published: June 2009

Introduction

The effect of sepsis on epidermal wound healing has not been previously studied. It was hypothesised that epidermal wound healing is disturbed in severe sepsis.

Methods

Blister wounds were induced in 35 patients with severe sepsis and in 15 healthy controls. The healing of the wounds was followed up by measuring transepidermal water loss and blood flow in the wound, reflecting the restoration of the epidermal barrier function and inflammation, respectively. The first set of suction blisters (early wound) was made within 48 hours of the first sepsis-induced organ failure and the second set (late wound) four days after the first wound. In addition, measurements were made on the intact skin.

Results

The average age of the whole study population was 62 years (standard deviation [SD] 12). The mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score on admission was 25 (SD 8). The two most common causes of infections were peritonitis and pneumonia. Sixty-six percent of the patients developed multiple organ failure. The decrease in water evaporation from the wound during the first four days was lower in septic patients than in the control subjects (56 g/m2 per hour versus 124 g/m2 per hour, P = 0.004). On the fourth day, septic patients had significantly higher blood flow in the wound compared with the control subjects (septic patients 110 units versus control subjects 47 units, P = 0.001). No difference in transepidermal water loss from the intact skin was found between septic patients and controls. Septic patients had higher blood flow in the intact skin on the fourth and on the eighth day of study compared with the controls.

Conclusions

The restoration of the epidermal barrier function is delayed and wound blood flow is increased in patients with severe sepsis.
SS-traveltime parameters from PP and PS reflections
Authors: Ursin Bjørn , Tygel Martin , Iversen Einar
Published: June 2009

The SS-wave traveltimes can be derived from PP- and PS-wave data with the previously derived [Formula: see text] method. We have extended this method as follows. (1) The previous requirement that sources and receivers be located on a common acquisition surface is removed, which makes the method directly applicable to PS-waves recorded on the ocean bottom and PP-waves recorded at the ocean surface. (2) By using the concept and properties of surface-to-surface propagator matrices, the second-order traveltime derivatives of the SS-waves are obtained. In the same way as for the original [Formula: see text] method, the proposed extension is valid for arbitrary anisotropic media. The propagator matrix and geometric spreading of an SS-wave reflected at a given point on a target reflector are obtained explicitly from the propagators of the PP- and PS-waves reflected at the same point. These additional parameters provided by the extended [Formula: see text] method can be used for a partial reconstruction of the SS-wave amplitude as well as for tomographic estimation of the elastic velocity model. A full simulation of the SS-wave, which includes reflection and transmission coefficients, cannot be obtained directly from recorded PP- and PS-wave amplitudes.