bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcriptional responses to polycyclic aromatic hydrocarbon-induced stress in Arabidopsis thalianareveal the involvement of hormone and defense signaling pathways
Authors: Weisman David , Alkio Merianne , Colón-Carmona Adán
Published: April 2010

Background

Polycyclic aromatic hydrocarbons (PAHs) are toxic, widely-distributed, environmentally persistent, and carcinogenic byproducts of carbon-based fuel combustion. Previously, plant studies have shown that PAHs induce oxidative stress, reduce growth, and cause leaf deformation as well as tissue necrosis. To understand the transcriptional changes that occur during these processes, we performed microarray experiments on Arabidopsis thaliana L. under phenanthrene treatment, and compared the results to published Arabidopsis microarray data representing a variety of stress and hormone treatments. In addition, to probe hormonal aspects of PAH stress, we assayed transgenic ethylene-inducible reporter plants as well as ethylene pathway mutants under phenanthrene treatment.

Results

Microarray results revealed numerous perturbations in signaling and metabolic pathways that regulate reactive oxygen species (ROS) and responses related to pathogen defense. A number of glutathione S-transferases that may tag xenobiotics for transport to the vacuole were upregulated. Comparative microarray analyses indicated that the phenanthrene response was closely related to other ROS conditions, including pathogen defense conditions. The ethylene-inducible transgenic reporters were activated by phenanthrene. Mutant experiments showed that PAH inhibits growth through an ethylene-independent pathway, as PAH-treated ethylene-insensitive etr1-4 mutants exhibited a greater growth reduction than WT. Further, phenanthrene-treated, constitutive ethylene signaling mutants had longer roots than the untreated control plants, indicating that the PAH inhibits parts of the ethylene signaling pathway.

Conclusions

This study identified major physiological systems that participate in the PAH-induced stress response in Arabidopsis. At the transcriptional level, the results identify specific gene targets that will be valuable in finding lead compounds and engineering increased tolerance. Collectively, the results open a number of new avenues for researching and improving plant resilience and PAH phytoremediation.
Genetic and transformation studies reveal negative regulation of ERS1 ethylene receptor signaling in Arabidopsis
Authors: Liu Qian , Xu Chan , Wen Chi-Kuang
Published: April 2010

Background

Ethylene receptor single mutants of Arabidopsis do not display a visibly prominent phenotype, but mutants defective in multiple ethylene receptors exhibit a constitutive ethylene response phenotype. It is inferred that ethylene responses in Arabidopsis are negatively regulated by five functionally redundant ethylene receptors. However, genetic redundancy limits further study of individual receptors and possible receptor interactions. Here, we examined the ethylene response phenotype in two quadruple receptor knockout mutants, (ETR1) ers1 etr2 ein4 ers2 and (ERS1) etr1 etr2 ein4 ers2, to unravel the functions of ETR1 and ERS1. Their functions were also reciprocally inferred from phenotypes of mutants lacking ETR1 or ERS1. Receptor protein levels are correlated with receptor gene expression. Expression levels of the remaining wild-type receptor genes were examined to estimate the receptor amount in each receptor mutant, and to evaluate if effects of ers1 mutations on the ethylene response phenotype were due to receptor functional compensation. As ers1 and ers2 are in the Wassilewskija (Ws) ecotype and etr1, etr2, and ein4 are in the Columbia (Col-0) ecotype, possible effects of ecotype mixture on ethylene responses were also investigated.

Results

Ethylene responses were scored based on seedling hypocotyl measurement, seedling and rosette growth, and relative Chitinase B (CHIB) expression. Addition of ers1 loss-of-function mutations to any ETR1-containing receptor mutants alleviated ethylene growth inhibition. Growth recovery by ers1 mutation was reversed when the ers1 mutation was complemented by ERS1p:ERS1. The addition of the ers2-3 mutation to receptor mutants did not reverse the growth inhibition. Overexpressing ERS1 receptor protein in (ETR1 ERS1)etr2 ein4 ers2 substantially elevated growth inhibition and CHIB expression. Receptor gene expression analyses did not favor receptor functional compensation upon the loss of ERS1.

Conclusions

Our results suggest that ERS1 has dual functions in the regulation of ethylene responses. In addition to repressing ethylene responses, ERS1 also promotes ethylene responses in an ETR1-dependent manner. Several lines of evidence support the argument that ecotype mixture does not reverse ethylene responses. Loss of ERS1 did not lead to an increase in total receptor gene expression, and functional compensation was not observed. The inhibitory effects of ERS1 on the ethylene signaling pathway imply negative receptor collaboration.
Deep vein thromboembolism after arthroscopy of the shoulder: two case reports and a review of the literature
Authors: Garofalo Raffaele , Notarnicola Angela , Moretti Lorenzo , Moretti Biagio , Marini Stefania , Castagna Alessandro
Published: April 2010

Background

Deep vein thrombosis (DVT) has an incidence of 1 case per 1000 inhabitants in the general population and it is very rare after arthroscopy of the shoulder. Therefore, the current guidelines do not advise the administration of DVT prophylaxis in shoulder arthroscopy procedures.

Cases presentation

We describe two cases of thrombosis of the arm after shoulder arthroscopy on a total of 10.452 shoulder arthroscopies performed during a period of ten years. One of two patients was further complicated by a bilateral pulmonary microembolism. In these two clinical cases the complication developed despite the absence of risk factors such as a concomitant neoplasm, thrombophilia, smoking habit, or a long duration of the procedure.

Conclusions

The DVT after shoulder arthroscopy procedure remain a very rare complication. However, in view of the growing number of patients undergoing this procedure, this figure is expected to rise. The clinician surgeon should take in mind this possible complication that normally appears in the first 3 weeks after surgery, so to perform anti-coagulant treatment. Further clinical studies are therefore warranted to assess the true risk of VTE. In fact, the presence of "minor" predisposing factors that are not routinely studied, as well as the postoperative immobilization period, are potential risk factors that, associated with the invasiveness of the arthroscopy procedure, could trigger a thromboembolism.
Nutraceutical augmentation of circulating endothelial progenitor cells and hematopoietic stem cells in human subjects
Authors: Mikirova Nina A , Jackson James A , Hunninghake Ron , Kenyon Julian , Chan Kyle WH , Swindlehurst Cathy A , Minev Boris , Patel Amit N , Murphy Michael P , Smith Leonard , Ramos Famela , Ichim Thomas E , Riordan Neil H
Published: April 2010

The medical significance of circulating endothelial or hematopoietic progenitors is becoming increasing recognized. While therapeutic augmentation of circulating progenitor cells using G-CSF has resulted in promising preclinical and early clinical data for several degenerative conditions, this approach is limited by cost and inability to perform chronic administration. Stem-Kine is a food supplement that was previously reported to augment circulating EPC in a pilot study. Here we report a trial in 18 healthy volunteers administered Stem-Kine twice daily for a 2 week period. Significant increases in circulating CD133 and CD34 cells were observed at days 1, 2, 7, and 14 subsequent to initiation of administration, which correlated with increased hematopoietic progenitors as detected by the HALO assay. Augmentation of EPC numbers in circulation was detected by KDR-1/CD34 staining and colony forming assays. These data suggest Stem-Kine supplementation may be useful as a stimulator of reparative processes associated with mobilization of hematopoietic and endothelial progenitors.
Pharmacological manipulation of GABA-driven activity in ovo disrupts the development of dendritic morphology but not the maturation of spinal cord network activity
Authors: Yoon Yone J , Gokin Alexander P , Martin-Caraballo Miguel
Published: April 2010

Background

In the adult nervous system, GABA acts as a major inhibitory neurotransmitter; however, at early stages of neurodevelopment, GABA receptor activation leads to membrane depolarization and accumulation of [Ca2+]i. The role of excitatory GABAergic neurotransmission in the development of the nervous system is not fully understood. In this study, we investigated the role of excitatory GABA-driven activity in regulating the dendritic morphology and network function in the developing chicken spinal cord.

Results

Both bicuculline, a GABA receptor antagonist, and muscimol, a GABA agonist, inhibit the generation of spontaneous network activity in the isolated spinal cord at E8 or E10, indicating that altering GABA receptor activation disrupts the generation of spontaneous network activity in the chicken spinal cord. Treatment of chicken embryos with bicuculline or muscimol between E5 and E8 (or between E8 and E10), inhibits the dendritic outgrowth of motoneurons when compared to vehicle-treated embryos. The inhibitory effect of bicuculline or muscimol on the dendritic morphology of motoneurons was likely due to inhibition of GABA-driven network activity since a similar effect was also observed following reduction of network activity by Kir2.1 overexpression in the spinal cord. The inhibitory effect of bicuculline or muscimol was not caused by an adverse effect on cell survival. Surprisingly, chronic treatment of chicken embryos with bicuculline or muscimol has no effect on the shape and duration of the episodes of spontaneous activity, suggesting that maturation of network activity is not altered by disruption of the dendritic outgrowth of motoneurons.

Conclusions

Taken together, these findings indicate that excitatory GABA receptor activation regulates the maturation of dendritic morphology in the developing spinal cord by an activity-dependent mechanism. However, inhibition of dendritic outgrowth caused by disruption of GABA-driven activity does not alter the maturation of spontaneous electrical activity generated by spinal cord networks, suggesting that compensatory mechanisms can reverse any adverse effect of dendritic morphology on network function.
Comparison of selected canine vector-borne diseases between urban animal shelter and rural hunting dogs in Korea
Authors: Lim Sun , Irwin Peter J , Lee SeungRyong , Oh MyungHwan , Ahn KyuSung , Myung BoYoung , Shin SungShik
Published: April 2010

A serological survey for Dirofilaria immitis, Anaplasma phagocytophilum, Ehrlichia canis, and Borrelia burgdorferi infections in rural hunting and urban shelter dogs mainly from southwestern regions of the Republic of Korea (South Korea) was conducted. From a total of 229 wild boar or pheasant hunting dogs, the number of serologically positive dogs for any of the four pathogens was 93 (40.6%). The highest prevalence observed was D. immitis (22.3%), followed by A. phagocytophilum (18.8%), E. canis (6.1%) and the lowest prevalence was B. burgdorferi (2.2%). In contrast, stray dogs found within the city limits of Gwangju showed seropositivity only to D. immitis (14.6%), and none of the 692 dogs responded positive for A. phagocytophilum, E. canis or B. burgdorferi antibodies. This study indicates that the risk of exposure to vector-borne diseases in rural hunting dogs can be quite high in Korea, while the urban environment may not be suitable for tick infestation on dogs, as evidenced by the low infection status of tick-borne pathogens in stray dogs.
The effect of carbon dioxide on near-death experiences in out-of-hospital cardiac arrest survivors: a prospective observational study
Authors: Klemenc-Ketis Zalika , Kersnik Janko , Grmec Stefek
Published: April 2010

Introduction

Near-death experiences (NDEs) are reported by 11-23% of cardiac arrest survivors. Several theories concerning the mechanisms of NDEs exist - including physical, psychological, and transcendental reasons - but so far none of these has satisfactorily explained this phenomenon. In this study, we investigated the effect of partial pressures of O2 and CO2, and serum levels of Na and K on the occurrence of NDEs in out-of-hospital cardiac arrest survivors.

Methods

A prospective observational study was conducted in the three largest hospitals in Slovenia. Fifty-two consecutive patients (median age 53.1 years, 42 males) after out-of-hospital cardiac arrest were included. The presence of NDEs was assessed with a self-administered Greyson's NDE scale. The initial partial pressure of end-tidal CO2, the arterial blood partial pressures of O2 and CO2 and the levels of Na and K in venous blood were analysed and studied. Univariate analyses and multiple regression models were used.

Results

NDEs were reported by 11 (21.2%) of the patients. Patients with higher initial partial pressures of end-tidal CO2 had significantly more NDEs (P < 0.01). Patients with higher arterial blood partial pressures of CO2 had significantly more NDEs (P = 0.041). Scores on a NDE scale were positively correlated with partial pressures of CO2 (P = 0.017) and with serum levels of potassium (P = 0.026). The logistic regression model for the presence of NDEs (P = 0.002) explained 46% of the variance and revealed higher partial pressures of CO2 to be an independent predictor of NDEs. The linear regression model for a higher score on the NDE scale (P = 0.001) explained 34% of the variance and revealed higher partial pressures of CO2, higher serum levels of K, and previous NDEs as independent predictors of the NDE score.

Conclusions

Higher concentrations of CO2 proved significant, and higher serum levels of K might be important in the provoking of NDEs. Since these associations have not been reported before, our study adds novel information to the field of NDEs phenomena.
Modulus ratio of dry rock based on differential effective-medium theory
Authors: Li Hongbing , Zhang Jiajia
Published: April 2010

There are two points of view with regard to the relationship between the dry-framework modulus ratio of bulk to shear modulus and porosity. One view, assumed by most empirical models such as the critical porosity model, is that the dry-framework modulus ratio is independent of porosity. However, this assumption is sometimes in disagreement with experiments. Another view supported by the differential effective-medium (DEM) theory is that the dry-framework modulus ratio depends on porosity. Ordinary differential equations (ODE) for bulk and shear moduli are coupled, and there is no analytical formula for the modulus ratio of dry porous rock. By assuming that the difference between the polarization factors of dry inclusions for bulk and shear modulus within the ODE has an almost linear relationship with the effective modulus ratio, an analytical solution for the dry-rock modulus ratio is derived from the ODE. The above linear relationship characterized by intercept [Formula: see text] and gradient [Formula: see text] is confirmed by the numerical results calculated from the analytical formulas for the three specific pore shapes: spherical pores, needle-shaped pores, and penny-shaped cracks. Then the validity of this assumption is tested by integrating the full DEM equation numerically. The analytical approximation gives a good estimate of the numerical results for the cases of the three given pore shapes. The dry-frame modulus ratio is monotonic with respect to porosity, and its monotonicity depends on the mineral-grain modulus ratio and the pore shape. The analytical formula can be simplified further to some popular models such as the critical porosity model by setting constants [Formula: see text] and [Formula: see text] to specific values. Predictions of the analytical formula compare favorably with real and synthetic sandstone data and granite data measured in the laboratory.
Taspoglutide, an Analog of Human Glucagon-Like Peptide-1 with Enhanced Stability and in Vivo Potency
Authors: Sebokova Elena , Christ Andreas D. , Wang Haiyan , Sewing Sabine , Dong Jesse Z. , Taylor John , Cawthorne Michael A. , Culler Michael D.
Published: April 2010

Taspoglutide is a novel analog of human glucagon-like peptide-1 [hGLP-1(7-36)NH2] in clinical development for the treatment of type 2 diabetes. Taspoglutide contains α-aminoisobutyric acid substitutions replacing Ala8 and Gly35 of hGLP-1(7-36)NH2. The binding affinity [radioligand binding assay using [125I]hGLP-1(7-36)NH2], potency (cAMP production in CHO cells stably overexpressing hGLP-1 receptor), and in vitro plasma stability of taspoglutide compared with hGLP-1(7-36)NH2 have been evaluated. Effects on basal and glucose-stimulated insulin secretion were determined in vitro in INS-1E cells and in vivo in normal rats. Taspoglutide has comparable affinity (affinity constant 1.1 ± 0.2 nm) to the natural ligand (affinity constant 1.5 ± 0.3 nm) for the hGLP-1 receptor and exhibits comparable potency in stimulating cAMP production (EC50 Taspo 0.06 nm and EC50 hGLP-1(7-36)NH2 0.08 nm). Taspoglutide exerts insulinotropic action in vitro and in vivo and retains the glucoincretin property of hGLP-1(7-36)NH2. Stimulation of insulin secretion is concentration dependent and evident in the presence of high-glucose concentrations (16.7 mm) with a taspoglutide concentration as low as 0.001 nm. Taspoglutide is fully resistant to dipeptidyl peptidase-4 cleavage (during 1 h incubation at room temperature with purified enzyme) and has an extended in vitro plasma half-life relative to hGLP-1(7-36)NH2 (9.8 h vs. 50 min). In vitro, taspoglutide does not inhibit dipeptidyl peptidase-4 activity. This study provides the biochemical and pharmacological basis for the sustained plasma drug levels and prolonged therapeutic activity seen in early clinical trials of taspoglutide. Excellent stability and potency with substantial glucoincretin effects position taspoglutide as a promising new agent for treatment of type 2 diabetes.
Establishment of a Novel Ghrelin-Producing Cell Line
Authors: Iwakura Hiroshi , Li Yushu , Ariyasu Hiroyuki , Hosoda Hiroshi , Kanamoto Naotetsu , Bando Mika , Yamada Go , Hosoda Kiminori , Nakao Kazuwa , Kangawa Kenji , Akamizu Takashi
Published: April 2010

To establish a tool to study ghrelin production and secretion in vitro, we developed a novel ghrelin-producing cell line, MGN3–1 (mouse ghrelinoma 3-1) cells from a gastric ghrelin-producing cell tumor derived from ghrelin-promoter Simian virus 40-T-antigen transgenic mice. MGN3-1 cells preserve three essential characteristics required for the in vitro tool for ghrelin research. First, MGN3-1 cells produce a substantial amount of ghrelin at levels approximately 5000 times higher than that observed in TT cells. Second, MGN3-1 cell expressed two key enzymes for acyl modification and maturation of ghrelin, namely ghrelin O-acyltransferase for acylation and prohormone convertase 1/3 for maturation and the physiological acyl modification and maturation of ghrelin were confirmed. Third, MGN3-1 cells retain physiological regulation of ghrelin secretion, at least in regard to the suppression by somatostatin and insulin, which is well established in in vivo studies. Thus, MGN3-1 cells are the first cell line derived from a gastric ghrelin-producing cell preserving secretion of substantial amounts of ghrelin under physiological regulation. This cell line will be a useful tool for both studying the production and secretion of ghrelin and screening of ghrelin-modulating drugs.
Genetic Determinants of Bone Density and Fracture Risk—State of the Art and Future Directions
Authors: Duncan Emma L. , Brown Matthew A.
Published: April 2010

Context: Osteoporosis is a common, highly heritable condition that causes substantial morbidity and mortality, the etiopathogenesis of which is poorly understood. Genetic studies are making increasingly rapid progress in identifying the genes involved.

Evidence Acquisition and Synthesis: In this review, we will summarize the current understanding of the genetics of osteoporosis based on publications from PubMed from the year 1987 onward.

Conclusions: Most genes involved in osteoporosis identified to date encode components of known pathways involved in bone synthesis or resorption, but as the field progresses, new pathways are being identified. Only a small proportion of the total genetic variation involved in osteoporosis has been identified, and new approaches will be required to identify most of the remaining genes.
Free Testosterone Levels Are Associated with Mobility Limitation and Physical Performance in Community-Dwelling Men: The Framingham Offspring Study
Authors: Krasnoff Joanne B. , Basaria Shehzad , Pencina Michael J. , Jasuja Guneet K. , Vasan Ramachandran S. , Ulloor Jagadish , Zhang Anqi , Coviello Andrea , Kelly-Hayes Margaret , D'Agostino Ralph B. , Wolf Philip A. , Bhasin Shalender , Murabito Joanne M.
Published: April 2010

Context: Mobility limitation is associated with increased morbidity and mortality. The relationship between circulating testosterone and mobility limitation and physical performance is incompletely understood.

Objective: Our objective was to examine cross-sectional and prospective relations between baseline sex hormones and mobility limitations and physical performance in community-dwelling older men.

Design, Setting, and Participants: We conducted cross-sectional and longitudinal analyses of 1445 men (mean age 61.0 ± 9.5 yr) who attended Framingham Offspring Study examinations 7 and 8 (mean 6.6 yr apart). Total testosterone (TT) was measured by liquid chromatography tandem mass spectrometry at examination 7. Cross-sectional and longitudinal analyses of mobility limitation and physical performance were performed with continuous (per sd) and dichotomized [low TT and free testosterone (FT) and high SHBG vs. normal] hormone levels.

Main Outcome Measures: Self-reported mobility limitation, subjective health, usual walking speed, and grip strength were assessed at examinations 7 and 8. Short physical performance battery was performed at examination 7.

Results: Higher continuous FT was positively associated with short physical performance battery score (β = 0.13; P = 0.008), usual walking speed (β = 0.02; P = 0.048), and lower risk of poor subjective health [odds ratio (OR) = 0.72; P = 0.01]. In prospective analysis, 1 sd increase in baseline FT was associated with lower risk of developing mobility limitation (OR = 0.78; 95% confidence interval = 0.62–0.97) and progression of mobility limitation (OR = 0.75; 95% confidence interval = 0.60–0.93). Men with low baseline FT had 57% higher odds of reporting incident mobility limitation (P = 0.03) and 68% higher odds of worsening of mobility limitation (P = 0.007).

Conclusions: Lower levels of baseline FT are associated with a greater risk of incident or worsening mobility limitation in community-dwelling older men. Whether this risk can be reduced with testosterone therapy needs to be determined by randomized trials.
Differential role of Rab proteins in ciliary trafficking: Rab23 regulates Smoothened levels
Authors: Boehlke Christopher , Bashkurov Mikhail , Buescher Andrea , Krick Theda , John Anne-Katharina , Nitschke Roland , Walz Gerd , Kuehn E. Wolfgang
Published: April 2010

The structure and function of the primary cilium as a sensory organelle depends on a motor-protein-powered intraflagellar transport system (IFT); defective IFT results in retinal degeneration and pleiotropic disorders such as the Bardet Biedl syndrome (BBS) and defective hedgehog (HH) signaling. Protein transport to the cilium involves Rab GTPases. Rab8, together with a multi protein complex of BBS proteins, recruits cargo to the basal body for transport to the cilium. Loss of Rab23 in mice recapitulates the HH phenotype but its function in HH signaling is unknown. Here we established a novel protocol, based on fluorescence recovery after photo-bleaching (FRAP), allowing the quantitative analysis of protein transport into the cilium of MDCK cells. We compared the effect of Rab8, Rab5 and Rab23 on the ciliary transport of the HH-associated transmembrane receptor Smoothened, the microtubular tip protein EB1, and the receptor protein Kim1. Ciliary FRAP confirmed the role of Rab8 in protein entry to the cilium. Dominant negative Rab5 had no impact on the ciliary transport of Smoothened or EB1, but slowed the recovery of the apical protein Kim1 in the cilium. Depletion of Rab23 or expression of dominant-negative Rab23 decreased the ciliary steady state specifically of Smoothened but not EB1 or Kim1, suggesting a role of Rab23 in protein turnover in the cilium.
Ability, Gender, and Performance Standards: Evidence from Academic Probation
Authors: Lindo Jason M , Sanders Nicholas J , Oreopoulos Philip
Published: April 2010

We use a regression discontinuity design to examine students' responses to being placed on academic probation. Consistent with a model of introducing performance standards, we find that being placed on probation at the end of the first year discourages some students from returning to school while improving the GPAs of those who do. We find heterogeneous responses across prior academic performance, gender, and native language, and discuss these results within the context of the model. We also find negative effects on graduation rates, particularly for students with the highest high school grades. (JEL I23, J16)
Housing Market Spillovers: Evidence from an Estimated DSGE Model
Authors: Iacoviello Matteo , Neri Stefano
Published: April 2010

We study sources and consequences of fluctuations in the US housing market. Slow technological progress in the housing sector explains the upward trend in real housing prices of the last 40 years. Over the business cycle, housing demand and housing technology shocks explain one-quarter each of the volatility of housing investment and housing prices. Monetary factors explain less than 20 percent, but have played a bigger role in the housing cycle at the turn of the century. We show that the housing market spillovers are nonnegligible, concentrated on consumption rather than business investment, and have become more important over time. (JEL E23, E32, E44, O33, R31)
Accounting for the Rise in Consumer Bankruptcies
Authors: Livshits Igor , MacGee James , Tertilt Michèle
Published: April 2010

Personal bankruptcies in the United States have increased dramatically, rising from 1.4 per thousand working age adults in 1970 to 8.5 in 2002. We use a heterogeneous agent life-cycle model with competitive lenders to evaluate several commonly offered explanations. We find that increased uncertainty (income shocks, expense uncertainty) cannot account quantitatively for the rise in bankruptcies. Instead, the rise in filings appears mainly to reflect changes in the credit market environment: a decrease in the transaction cost of lending and in the cost of bankruptcy. We also argue that the abolition of usury laws and other legal changes were unimportant. (JEL D14, E44, G21, G28)
Offshoring in a Ricardian World
Authors: Rodríguez-Clare Andrés
Published: April 2010

This paper proposes a Ricardian model to understand the short-run and long-run aggregate effects of increased fragmentation and offshoring on rich and poor countries. The short-run analysis shows that, when offshoring is sufficiently high, further increases in offshoring benefit the poor country and hurt the rich country. But these effects may be reversed in the long run as countries adjust their research efforts in response to increased offshoring. In particular, in the long run, the rich country always gains from increased offshoring, whereas poor countries see their static gains partially eroded by a decline in their research efforts. (JEL F12, F23, L24, M16)
Business Volatility, Job Destruction, and Unemployment
Authors: Davis Steven J , Faberman R. Jason , Haltiwanger John , Jarmin Ron , Miranda Javier
Published: April 2010

Unemployment inflows fell from 4 percent of employment per month in the early 1980s to 2 percent by the mid 1990s. Using low frequency movements in industry-level data, we estimate that a 1 percentage point drop in the quarterly job destruction rate lowers the monthly unemployment inflow rate by 0.28 points. By our estimates, declines in job destruction intensity account for 28 (55) percent of the fall in unemployment inflows from 1982 (1990) to 2005. Slower job destruction accounts for similar fractions of long-term declines in the rate of unemployment. (JEL E24, E32, J64)
Financial Stability, the Trilemma, and International Reserves
Authors: Obstfeld Maurice , Shambaugh Jay C , Taylor Alan M
Published: April 2010

The rapid growth of international reserves, a development concentrated in the emerging markets, remains a puzzle. In this paper, we suggest that a model based on financial stability and financial openness goes far toward explaining reserve holdings in the modern era of globalized capital markets. The size of domestic financial liabilities that could potentially be converted into foreign currency (M2), financial openness, the ability to access foreign currency through debt markets, and exchange rate policy are all significant predictors of reserve stocks. Our empirical financial-stability model seems to outperform both traditional models and recent explanations based on external short-term debt. (JEL E23, E43, E44, F31, F32, F34)
Putting the Parts Together: Trade, Vertical Linkages, and Business Cycle Comovement
Authors: di Giovanni Julian , Levchenko Andrei A
Published: April 2010

Countries that trade more with each other exhibit higher business cycle correlation. This paper examines the mechanisms underlying this relationship using a large cross-country, industry-level panel dataset of manufacturing production and trade. We show that sector pairs that experience more bilateral trade exhibit stronger comovement. Vertical linkages in production are an important explanation behind this effect: bilateral international trade increases comovement significantly more in cross-border industry pairs that use each other as intermediate inputs. Our estimates imply that these vertical production linkages account for some 30 percent of the total impact of bilateral trade on the business cycle correlation. (JEL E32, F14, F43)
A pilot study on the prevalence of sexually transmitted infections among clients of brothel-based female sex workers in Jessore, Bangladesh
Authors: Huq M , Chawdhury F A H , Mitra D K , Islam M A , Salahuddin G , Das J , Rahman M
Published: April 2010

Summary

The prevalence of bacterial sexually transmitted infections among clients of female sex workers (FSWs) was studied. A total of 156 condoms were collected from clients of 13 sex workers during three consecutive days. Condoms used by clients of FSWs were collected and DNA was extracted from the seminal fluid and used for the diagnosis of Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis by polymerase chain reaction. The prevalence of N. gonorrhoeae, C. trachomatis and T. vaginalis among clients of FSWs was 4.5% (7/156), 2.5% (4/156) and 7% (11/156), respectively.
Comparison between turnaround time and cost of herpes simplex virus testing by cell culture and polymerase chain reaction from genital swabs
Authors: Saeed K , Pelosi E
Published: April 2010

Summary

Clinical diagnosis of genital herpes simplex virus (HSV) (GH) infection is insensitive and non-specific and requires laboratory confirmation. In this study we compared viral culture and the amplification of HSV DNA by polymerase chain reaction (PCR) with respect to turnaround time and cost. We compared 182 swabs submitted to our laboratory between March and May 2005, which were tested using MRC-5 cell culture, with 168 genital swabs submitted during the same months in 2006, and were tested by PCR.

We concluded that PCR testing in our laboratory has significantly improved the turnaround time, with 68.4% of tests having been reported in less than 24 hours. This in turn significantly improved the service provided for the diagnosis of genital herpes without additional costs.
Relations between cardiovascular risk estimates and subclinical atherosclerosis in naïve HIV patients: results from the HERMES study
Authors:   The Hermes Study Group, De Socio G V L , Martinelli C , Ricci E , Orofino G , Valsecchi L , Vitiello P , Martinelli L , Quirino T , Maggi P , Bonfanti P
Published: April 2010

Summary

The aim of the study was to evaluate the cardiovascular risk factors associated with subclinical carotid atherosclerosis in antiretroviral therapy-naïve HIV-infected patients. The HERMES (HIV Exposure and Risk of Metabolic Syndrome) study enrolled therapy-naïve patients attending hospitals in the Italian coordination group for the study of allergies and HIV infection (CISAI [Coordinamento Italiano per lo Studio Allergia e Infezione da HIV]) in 2007. It was designed to identify metabolic syndrome (MS) and cardiovascular risk factors. The present analysis is a nested cross-sectional study with a subset of patients examined by carotid ultrasonography. Consecutive antiretroviral therapy-naïve HIV patients attending the facilities involved in the CISAI were included. Their 10-year probability of cardiovascular events was calculated using the Framingham Risk Score (FRS) and three other cardiovascular algorithms (the Global Framingham Risk Score – GFRS, ‘Progetto Cuore’ and ‘SCORE’). Vascular age was estimated using a new model derived from GFRS and was compared with chronological age. The diagnosis of MS was based on the National Cholesterol Education Programme and International Diabetes Federation (IDF) definitions. Subclinical atherosclerosis was determined as ultrasound carotid intima-media thickness >0.9 mm. Out of 140 patients enrolled in the HERMES study by the four centres participating in the nested study, a total of 72 (51.4%) subjects, with no overt cardiovascular disease, were examined using carotid ultrasonography. The median age was 40 years, 79.2% men. The vascular age was 7.6 years higher than the chronological age. The factors associated with subclinical atherosclerosis were age (P < 0.0001), vascular age (P = 0.0002), body mass index (P = 0.003), waist circumference (P = 0.0002), MS (IDF definition, P = 0.004) and all the cardiovascular (CV) models (FRS, P = 0.01, GFRS, P = 0.002, Progetto Cuore, P = 0.018, SCORE, P = 0.03). Independent of other significant factors, waist circumference was significantly associated with pathological results (P = 0.007). The GFRS (area under the receiver-operating characteristic curves, 0.78; P < 0.001) had slightly better predictive accuracy than the other three CV models (FRS, areas under the curve [AUC] = 0.71, P = 0.003; Progetto Cuore, AUC = 0.74, P = 0.0005; SCORE, AUC = 0.77, P < 0.0001); 55% of patients at intermediate risk (6–20%) had subclinical carotid lesions. Subclinical carotid lesions had a highly significant direct association with all the CV risk predictors. The GFRS and vascular age were highly predictive. We recommend a carotid ultrasonographic examination at least among HIV patients with GFRS >6% or with an elevated waist circumference.
Historical perspective of sexually transmitted infections and their control in Peru
Authors: García P J
Published: April 2010

Summary

In designing an effective national response to sexually transmitted infections (STIs), one must incorporate a historical perspective of previous efforts that have addressed different aspects of STIs. One must understand who have been the key players, what aspects of STIs were the focus of efforts (prevention, treatment or control), and which, if any, societal subgroups were targeted (i.e. sex workers, military, men who have sex with men [MSM], etc.). In addition, one must consider historical and modern attitudes towards sex, sexuality and STIs, especially in terms of taboos and stigmas that may be attached to each. Most importantly, one must recognize which efforts have succeeded, which have failed, and why. This paper presents a historical overview of the perceptions of and responses to STIs at different points in Peru's history, and discusses current efforts to build upon past successes and avoid repeating previous failures that could be helpful for other countries in the Latin American region.
Prognostic value of C-reactive protein in HIV-infected patients with Pneumocystis jirovecii pneumonia
Authors: Sage E K , Noursadeghi M , Evans H E , Parker S J , Copas A J , Edwards S G , Miller R F
Published: April 2010

Summary

C-reactive protein (CRP) is a sensitive marker of inflammation and tissue damage. We aimed to describe CRP responses in HIV-infected patients presenting with Pneumocystis pneumonia (PCP), bacterial pneumonia (BP) and pulmonary tuberculosis (TB) and, in patients with PCP, to identify if elevated CRP has prognostic significance. Data obtained by case-note review of consecutive HIV-infected adults with acute respiratory episodes included admission CRP (elevated >5 mg/L), haemoglobin, white blood count, CD4 count and partial pressure of oxygen in the blood (PaO2), presence of pulmonary co-pathology/intercurrent infection and outcome (survival). Median (range) CRP in patients with BP = 120 mg/L (<5–620 mg/L), TB = 44 mg/L (<5–256.3 mg/L) and PCP = 35 mg/L (<5–254 mg/L). CRP was elevated in 93/103 (90.3%) patients with PCP; six patients died; and all had an elevated CRP. PaO2 and CRP values were associated as follows: average CRP levels declined by 10% (95% confidence interval [CI] 0.20%) per kPa increase in PaO2 = 0.002. Factors associated with death were higher CRP, odds ratio (OR) (95% CI) = 5.30 (1.61 to 17.51) per 100 mg/L increase, P = 0.006 and haemoglobin, OR (95% CI) = 0.52 (0.29 to 0.93) per g/dL, P = 0.033. CRP is elevated in the majority of HIV-infected patients with PCP, BP and TB. Admission CRP measurement lacks specificity, but in PCP elevations of CRP are associated with disease severity (PaO2) and poor outcome and might be used prognostically, together with other mortality risk factors; further prospective evaluation is needed.
Sexuality education policies and sexually transmitted disease rates in the United States of America
Authors: Hogben M , Chesson H , Aral S O
Published: April 2010

Summary

The aim of the study was to test for relationships between state-level sex educational policies and sexually transmitted disease (STD) rates. We analysed US case reports of gonorrhoea and chlamydial infection for 2001–2005 against state policies for abstinence coverage in sexuality education, using the proportion of the population per state who identified as black (aged 15–24 years) as a covariate. We also tested for effects on 15–19 year olds versus 35–39 year olds and tuberculosis rates (the latter to ensure findings applied only to STD). States with no mandates for abstinence had the lowest mean rates of infection among the overall population and among adolescents. States with mandates emphasizing abstinence had the highest rates; states with mandates to cover (but not emphasize) abstinence fell in between. Rates in some states covering abstinence changed faster than in others, as reflected in sharper declines (gonorrhoea) or slower increases (chlamydial infection). These effects were not shown for tuberculosis or 35–39 year olds. Having no abstinence education policy has no apparent effect on STD rates for adolescents. For states with elevated rates, policies mandating coverage may be useful, although policies emphasizing abstinence show no benefit.
Care pathways: An ethnographic description of the field
Authors: Allen Davina
Published: April 2010

This paper describes an ethnographic study of the care pathway community. Qualitative data generated through attendance at the annual care pathways conference and a regional group network are assembled in order to present an interpretation of the spread of pathways across the health-care field and identify the stakeholders involved, as well as their interests, aspirations and alignments. The growing popularity of care pathway methodology can be explained by its effectiveness in reconciling clinical and management interests in offering a single solution to shared health service problems. However, this breadth of appeal disguises tensions between clinical and management agenda which creates challenges in inscribing this multiplicity of interests into the pathway design. This helps to explain the challenges of pathway development and the range of interventions to which the term ‘pathway’ is applied. In a second, companion paper, I consider how the community has responded to these concerns and draw on social sciences concepts to offer an alternative approach.
Critical pathway for patients undergoing aortic-surgery: Impact on postoperative care at an intensive care unit in Sweden
Authors: Lyckner Sara , Sjöberg Petronella Bjurling , Engström Gabriella
Published: April 2010

In January 2007, the intensive care unit (ICU) at a Swedish hospital introduced a critical pathway for patients undergoing aortic-surgery. The aim of this study is to evaluate the impact of this initiative, with regard to postoperative care in an ICU. A comparison of two patient groups - 17 patients treated one year before and 20 patients treated one year after the introduction of the pathway - was performed, and considered nasogastric tube, intake of clear fluids, intake of nutrition drink or meal, breathing exercise and mobilization. No statistically significant differences in mean age, gender, anaesthetic risk factors, peroperative bleeding, length of surgery and length of mechanic ventilation between the groups existed. The patients in the pathway group had their nasogastric tube removed significantly earlier (P < 0.05) and received intake of clear fluids and nutrition drink or meal significantly (P < 0.05) earlier than patients in the control group. Critical pathway for patients undergoing aortic-surgery has a positive impact on postoperative care. Aortic-surgery patients treated in accordance with the pathway at the ICU received nursing interventions earlier than patients who were treated without pathway, which is crucial for the quality of care and optimal outcome.
Simulation of Career Development in the European Commission
Authors: Onggo Stephan , Pidd Michael , Soopramanien Didier , Worthington Dave
Published: April 2010

The European Commission (the Commission) employs more than 22,000 officials who provide administrative services to the European Union. In 2003, the Commission introduced a performance appraisal and promotion system based on points that the officials earn each year. In 2006, the Commission realized that the system needed to be revised. To support the review process, the Commission invited tenders for a project to develop simulation models that it could use to project the future performance of the existing system. A team from Lancaster University won the bid and subsequently worked closely with Commission officials to develop a new system. In 2009, the stakeholders in the Commission's performance appraisal and promotion system agreed to implement the improved system. The simulation model is unusual in the field of manpower planning because it models the consequences of appraisal-system rules. It uses novel, accurate, and efficient sampling techniques that are based on regression models of the underlying relationships in the data. The model was a crucial part of renegotiating the appraisal and promotion system and implementing a new system.
Realigning Service Operations Strategy at DHL Express
Authors: Coltman Tim , Gattorna John , Whiting Stuart
Published: April 2010

This paper describes the approach that DHL used to respond to aggressive revenue and profit targets set by its Asia-Pacific regional management board. DHL's reaction to these targets was to redefine its strategic service vision by systematically aligning its internal support functions with distinct buyer behavior structures. Specifically, we developed a model based on the tangible and intangible factors that directly influence a customer's choice of a third-party logistics provider. Next, we reverse engineered the service provider's delivery system to align with each customer's preferred buying behavior. DHL's share of wallet and profitability immediately improved, enabling the company to maintain its leading position in the market. Quantitative and qualitative results show an improvement in DHL's market share, customer satisfaction scores, and employee opinion survey results.
Impossible Frontiers
Authors: Brennan Thomas J. , Lo Andrew W.
Published: April 2010

A key result of the capital asset pricing model (CAPM) is that the market portfolio—the portfolio of all assets in which each asset's weight is proportional to its total market capitalization—lies on the mean-variance-efficient frontier, the set of portfolios having mean-variance characteristics that cannot be improved upon. Therefore, the CAPM cannot be consistent with efficient frontiers for which every frontier portfolio has at least one negative weight or short position. We call such efficient frontiers “impossible,” and show that impossible frontiers are difficult to avoid. In particular, as the number of assets, n, grows, we prove that the probability that a generically chosen frontier is impossible tends to one at a geometric rate. In fact, for one natural class of distributions, nearly one-eighth of all assets on a frontier is expected to have negative weights for every portfolio on the frontier. We also show that the expected minimum amount of short selling across frontier portfolios grows linearly with n, and even when short sales are constrained to some finite level, an impossible frontier remains impossible. Using daily and monthly U.S. stock returns, we document the impossibility of efficient frontiers in the data.
Positioning and Pricing in a Variety Seeking Market
Authors: Sajeesh S. , Raju Jagmohan S.
Published: April 2010

We study competitive positioning and pricing strategies in markets where consumers seek variety. Variety seeking behavior is modeled as a decrease in the willingness to pay for the product purchased on the previous purchase occasion. Using a three-stage Hotelling-type model, we show that the presence of variety seeking consumers reduces product differentiation offered in equilibrium, thereby explaining some otherwise counterintuitive findings in empirical research. We find that firms charge higher prices in Period 1 and lower prices in Period 2. The lower price in Period 2 represents the price incentive that firms need to offer to prevent the variety seeking consumers from switching. Furthermore, we find that the observed switching in a market may not fully capture the true magnitude of the underlying variety seeking tendencies among consumers. Finally, we show that the presence of variety seeking consumers leads to lower firm profits and a higher consumer surplus. Surplus increases for variety seeking consumers as well as regular consumers. Therefore, the presence of variety seeking consumers benefits everyone in the market.