bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficiency of a pneumatic device in controlling cuff pressure of polyurethane-cuffed tracheal tubes: a randomized controlled study
Authors: Jaillette Emmanuelle , Zerimech Farid , De Jonckheere Julien , Makris Demosthenes , Balduyck Malika , Durocher Alain , Duhamel Alain , Nseir Saad
Published: December 2013

Background

The primary objective of this study was to determine the efficiency of a pneumatic device in controlling cuff pressure (Pcuff) in patients intubated with polyurethane-cuffed tracheal tubes. Secondary objectives were to determine the impact of continuous control of Pcuff, and cuff shape on microaspiration of gastric contents.

Methods

Prospective randomized controlled study. All patients requiring intubation and mechanical ventilation ≥48 h were eligible. The first 32 patients were intubated with tapered polyurethane-cuffed, and the 32 following patients were intubated with cylindrical polyurethane-cuffed tracheal tubes. Patients randomly received 24 h of continuous control of Pcuff using a pneumatic device (Nosten®), and 24 h of routine care of Pcuff using a manometer. Target Pcuff was 25 cmH2O. Pcuff was continuously recorded, and pepsin was quantitatively measured in all tracheal aspirates during these periods.

Results

The pneumatic device was efficient in controlling Pcuff (med [IQ] 26 [24, 28] vs 22 [20, 28] cmH2O, during continuous control of Pcuff and routine care, respectively; p = 0.017). In addition, percentage of patients with underinflation (31% vs 68%) or overinflation (53% vs 100%) of tracheal cuff, and percentage of time spent with underinflation (0.9 [0, 17] vs 14% [4, 30]) or overinflation (0 [0, 2] vs 32% [9, 54]) were significantly (p < 0.001) reduced during continuous control of Pcuff compared with routine care.

No significant difference was found in microaspiration of gastric content between continuous control of Pcuff compared with routine care, or between patients intubated with tapered compared with cylindrical polyurethane-cuffed tracheal tubes.

Conclusion

The pneumatic device was efficient in controlling Pcuff in critically ill patients intubated with polyurethane-cuffed tracheal tubes.

Trial registration

The Australian New Zealand Clinical Trials Registry (NCT01351259)
Outcomes following percutaneous coronary intervention and coronary artery bypass grafting surgery in Chinese, South Asian and white patients with acute myocardial infarction: administrative data analysis
Authors: Gasevic Danijela , Khan Nadia A , Qian Hong , Karim Shahzad , Simkus Gerald , Quan Hude , Mackay Martha H , O’Neill Blair J , Ayyobi Amir F
Published: December 2013

Background

Little is known on whether there are ethnic differences in outcomes following percutaneous coronary intervention (PCI) and coronary artery bypass grafting surgery (CABG) after acute myocardial infarction (AMI). We compared 30-day and long-term mortality, recurrent AMI, and congestive heart failure in South Asian, Chinese and White patients with AMI who underwent PCI and CABG.

Methods

Hospital administrative data in British Columbia (BC), Canada were linked to the BC Cardiac Registry to identify all patients with AMI who underwent PCI (n = 4729) or CABG (n = 1687) (1999–2003). Ethnicity was determined from validated surname algorithms. Logistic regression for 30-day mortality and Cox proportional-hazards models were adjusted for age, sex, socio-economic status, severity of coronary disease, comorbid conditions, time from AMI to a revascularization procedure and distance to the nearest hospital.

Results

Following PCI, Chinese had higher short-term mortality (Odds Ratio (OR): 2.36, 95% CI: 1.12-5.00; p = 0.02), and South Asians had a higher risk for recurrent AMI (OR: 1.34, 95% CI: 1.08-1.67, p = 0.007) and heart failure (OR 1.81, 95% CI: 1.00-3.29, p = 0.05) compared to White patients. Risk of heart failure was higher in South Asian patients who underwent CABG compared to White patients (OR (95% CI) = 2.06 (0.92-4.61), p = 0.08). There were no significant differences in mortality following CABG between groups.

Conclusions

Chinese and South Asian patients with AMI and PCI or CABG had worse outcomes compared to their White counterparts. Further studies are needed to confirm these findings and investigate potential underlying causes.
An epidemiological survey on low birth weight infants in China and analysis of outcomes of full-term low birth weight infants
Authors: Chen Yi , Li Guanghui , Ruan Yan , Zou Liying , Wang Xin , Zhang Weiyuan
Published: December 2013

Background

Low birth weight (LBW) is one of the leading causes of adverse perinatal outcomes and is closely related to neonatal disease and death. The incidence of LBW has been increasing. The aim of this study was to investigate the current incidence rate and factors affecting low birth weight infants and perinatal outcomes of full-term low birth weight infants in mainland China.

Methods

This paper describes a retrospective analysis of children born in 39 hospitals of different types in 14 different provinces, municipalities, and autonomous regions in seven districts within China throughout 2011. The data were first collected in hardcopy format and then entered into computer network databases. Data covering a total of 112,441 cases were collected. Cases were excluded if data were incomplete and in the case of miscarriage before 24 weeks of gestation, multiple pregnancies, or induction of labor due to fetal malformation, intrauterine death, and other reasons, leaving a total of 101,163 cases. SPSS 18.0 and SAS 9.2 statistical packages were used to analyze the collected data.

Results

According to this research, the incidence of LBW in mainland China was 6.1%, which is higher than the 5.87% reported in 2000, and it varied across different areas. The incidence of LBW was significantly higher in tertiary care hospitals than in secondary care hospitals. LBW was found to be associated with maternal age of less than 20 years, low level of maternal education, previous histories of adverse pregnancies, and with pregnancy comorbidities and complications, such as hypertensive disorders during pregnancy, anemia, oligohydramnios, premature rupture of membranes, and gestational diabetes. The rates of stillbirths, severe neonatal asphyxia, and deaths among full-term LBW infants were 2.42%, 0.83%, and 3.49%, respectively. The rates of stillbirths and neonatal deaths among full-term LBW infants born by caesarean section were 0.5% and 1.0%, respectively, which was lower than vaginal delivery.

Conclusions

The incidence of LBW has increased in China. LBW is a leading cause of adverse pregnancy outcomes. Health care during pregnancy and management of high-risk factors for LBW may reduce the incidence of LWB and the death rate of LBW infants.
The impact of a cardiovascular health awareness program (CHAP) on reducing blood pressure: a prospective cohort study
Authors: Ye Chenglin , Foster Gary , Kaczorowski Janusz , Chambers Larry W , Angeles Ricardo , Marzanek-Lefebvre Francine , Laryea Stephanie , Thabane Lehana , Dolovich Lisa
Published: December 2013

Background

Hypertension is an important and modifiable cardiovascular risk factor that remains under-detected and under-treated, especially in the older individuals. Community-led interventions that integrate primary health care and local resources are promising approaches to improve awareness and management of hypertension and other cardiovascular risk factors. We aimed to evaluate the effect of a community-based Cardiovascular Health Awareness Program (CHAP) on participants’ blood pressure.

Methods

This study followed a cohort of community residents that participated in CHAP across 22 mid-sized Ontario communities over an 18-month period. The participants’ baseline risk factors, including blood pressure, and subsequent measures of blood pressure were recorded. We employed a bivariate linear mixed-effect model to estimate the change of systolic and diastolic blood pressure over time among the participants who attended more than two CHAP sessions.

Results

Of 13,596 participants, 2498 attended more than two CHAP sessions. For those repeated participants (attending more than two sessions) initially identified with high blood pressure, the average reduction of systolic blood pressure was from 142 to 123 mmHg over an 18-month period, a monthly rate ratio of 0.992 (95% CI: 0.991,0.994; p < 0.01). Similarly, the average reduction of diastolic blood pressure was from 78 to 69 mmHg, a monthly rate ratio of 0.993 (95% CI: 0.991,0.994; p < 0.01). The average blood pressure of the participants with normal baseline blood pressure remained controlled and unchanged. We also found that older adult participants who lived alone, were diagnosed with hypertension, reported healthier eating habits, and presented with a higher baseline systolic blood pressure had significantly greater odds of attending more than one session.

Conclusions

CHAP was associated with a reduction in systolic and diastolic blood pressure for those participants who attended more than one session. The magnitude of blood pressure reductions was significant clinically and statistically.
Massive heterotopic ossification associated with late deficits in posterior wall of acetabulum after failed acetabular fracture operation
Authors: Zhang Yuntong , Xie Yang , Xu Shuogui , Zhang Chuncai
Published: December 2013

Background

Heterotopic ossification is a common postoperative complication of acetabular fracture. However, functionally significant heterotopic ossification with associated late bone defects in the posterior wall of the acetabulum is rare and challenging to treat. When heterotopic ossification is a late complication of failed acetabular fracture operation, it is disabling and may only be treated by THA. THA is highly susceptible to premature failure in young and active patients and may require numerous revisions.

Case presentation

This article describes a 40-year-old man with massive heterotopic ossification associated with late bone defects in the posterior wall of the acetabulum after a failed acetabular fracture operation. The primary fracture type was a 62-A2.3 fracture according to the AO/OTA Classification.Surgical excision and anatomical reconstruction of the acetabular wall using heterotopic ossific bone were performed 10 months after the fracture repair. Postoperatively, indomethacin was administered for prophylaxis against recurrence of heterotopic ossification, and hip range of motion was progressively increased. At 5 years and 6 months follow-up, the patient’s pain was relieved and hip function had recovered. Though radiography and CT showed minimal subchondral cysts and mild joint-space narrowing, there was no evidence of graft resorption, progressive posttraumatic osteoarthritis or necrosis of the femoral head.

Conclusion

To the authors’ knowledge, this is the first case of such a challenging condition. Although it is an extremely rare case, it provides an attractive option for avoiding THA, as the long-term follow-up shows a satisfactory outcome.
Nitrogen catabolite repressible GAP1 promoter, a new tool for efficient recombinant protein production in S. cerevisiae
Authors: Debailleul Fabien , Trubbia Cataldo , Frederickx Nancy , Lauwers Elsa , Merhi Ahmad , Ruysschaert Jean-Marie , André Bruno , Govaerts Cédric
Published: December 2013

Background

Decades of work requiring heterologous expression of eukaryotic proteins have shown that no expression system can be considered as the panacea and the appropriate expression strategy is often protein-dependent. In a large number of cases, yeasts have proven to be reliable organisms for heterologous protein expression by combining eukaryotic cellular organization with the ease of use of simpler microorganisms.

Results

During this work, a novel promoter system based on the nitrogen catabolite regulation has been developed to produce the general amino acid permease (Gap1) in its natural host, the yeast Saccharomyces cerevisiae. A simple purification protocol was also established that allows to purify milligrams of Gap1 from cells cultivated in a five liters bio-reactor. In order to test the ability of the system to be used for expression of other proteins, the yeast specific transporter of γ-aminobutyric acid (Uga4), a human vesicular transporter of glutamate (Vglut1) and a small secreted glycoprotein (MD-2) were also expressed using the nitrogen catabolite regulation. All proteins were fused to GFP and their presence and localization were confirmed by western blot analysis and fluorescence microscopy.

Conclusions

Our work shows that the nitrogen catabolite repressible GAP1 promoter can be used to obtain high levels of recombinant protein while allowing for large biomass production in S. cerevisiae. This approach can be used to express membrane and soluble proteins from higher eukaryotes (from yeast to human). Therefore, this system stands as a promising alternative to commonly used expression procedure in yeasts.
Fast marching over the 2D Gabor magnitude domain for tongue body segmentation
Authors: Cui Zhenchao , Zhang Hongzhi , Zhang David , Li Naimin , Zuo Wangmeng
Published: December 2013

Tongue body segmentation is a prerequisite to tongue image analysis and has recently received considerable attention. The existing tongue body segmentation methods usually involve two key steps: edge detection and active contour model (ACM)-based segmentation. However, conventional edge detectors cannot faithfully detect the contour of the tongue body, and the initialization of ACM suffers from the edge discontinuity problem. To address these issues, we proposed a novel tongue body segmentation method, GaborFM, which initializes ACM by performing fast marching over the two-dimensional (2D) Gabor magnitude domain of the tongue images. For the enhancement of the contour of the tongue body, we used the 2D Gabor magnitude-based detector. To cope with the edge discontinuity problem, the fast marching method was utilized to connect the discontinuous contour segments, resulting in a closed and continuous tongue body contour for subsequent ACM-based segmentation. Qualitative and quantitative results showed that GaborFM is superior to the other methods for tongue body segmentation.
Melatonin reduces migratory restlessness in Sylvia warblers during autumnal migration
Authors: Fusani Leonida , Coccon Francesca , Rojas Mora Alfonso , Goymann Wolfgang
Published: December 2013

Introduction

A remarkable aspect of bird migration is its nocturnality, particularly common in Passeriformes. The switch in activity from purely diurnal to also nocturnal is evident even in caged birds that during migratory periods develop an intense nocturnal restlessness, termedZugunruhe. The mechanisms that control this major change in activity are mostly unknown. Previous work withSylviawarblers suggested an involvement of melatonin, a hormone associated with day-night cycles in most vertebrates. In a recent study we found no effects of melatonin administration onZugunruheduring spring migration. However, previous studies indicated that the response to melatonin manipulation could differ between spring and autumn migration, which are in fact separate life history stages. Here we tested whether a non-invasive treatment with melatonin can alterZugunruhein wild garden warblersS. borinand blackcapsS. atricapillasubject to temporary captivity at an autumnal stopover site. Food availability in the cage (yes/no) was added as a second factor because previous work showed that it enhancedZugunruhe.

Results

The melatonin treatment significantly decreased the amount ofZugunruhe, while the availability of food only tended to increase the amount ofZugunruhe. Fuel deposits also had a strong effect on the amount of nocturnal activity: lean birds with a fat score of 1 showed significantly lessZugunruhethan fatter birds. The change in body mass during the time spent in the recording cage depended on food availability, but not on any of the other factors.

Conclusions

This study shows that the migratory programme of twoSylviawarblers can be manipulated by administration of exogenous melatonin and confirms that this hormone is involved in the control of migratory behaviour. To our knowledge, this is one of the first demonstrations that the autumn migratory programme can be altered by hormonal manipulation in migrating birds. The comparison with a similar study carried out with the same modalities during spring migration suggests that there are seasonal differences in the sensitivity of the migratory programme to hormonal factors. In birds breeding in the northern hemisphere, the importance of a timely arrival to the breeding sites could explain why the control of the migratory programme is more rigid in spring.
The feasibility of evaluating radiation dose to the heart by integrating kilovoltage-cone beam computed tomography in stereotactic body radiotherapy of early non-small-cell lung cancer patients
Authors: Liu Chengxin , Gong Guanzhong , Guo Chen , Liu Tonghai , Lu Jie , Zhao Hong , Dong Wei , Yin Yong
Published: December 2013

Background

To investigate the feasibility of contouring the planning risk organ volume (PRV) for the heart, and to determine the probability of evaluating radiation dose to the heart using kilovoltage-cone beam computed tomography (kV-CBCT) in early-stage non-small-cell lung cancer (NSCLC) patients, who received stereotactic body radiotherapy (SBRT).

Materials and methods

Seventeen NSCLC patients who received SBRT (5Gy/f × 10f dose) were enrolled and subjected to CBCT and CT imaging analyses to plan treatment. Sequential planning CBCT images of individual patient’s hearts were analyzed for reproducibility of heart contouring and volume. Comparative analyses were made between the planning CT- and CBCT-detected heart margins and dose-volume indices for treatment.

Results

The heart volume from planning CT images was significantly smaller than that from CBCT scans (p < 0.05), and the volumes based on the different series of CBCT images were similar (p > 0.05).The overlap of the heart region on the same anatomical section between the first series of CBCT scans and other scans reached 0.985 ± 0.020 without statistically significant differences (p > 0.05). The mean margins of the heart from planning CT and CBCT scans were 10.5 ± 2.8 mm in the left direction, 5.9 ± 2.8 mm in the right direction, 2.2 ± 1.6 mm in the direction of the head, 3.3 ± 2.2 mm in the direction of the foot, 6.7 ± 1.1 mm in the anterior direction, and 4.5 mm ± 2.5 mm in the posterior direction. All relative and absolute dose-volume indices obtained from CBCT images were significantly larger than those from planning CT scans (p < 0.05), with the exception of the volume in the 5Gy region.

Conclusion

The PRV of heart contouring based on kV-CBCT is feasible with good reproducibility. More accurate and objective dose-volume indices may be obtained for NSCLC patients by using kV-CBCT, instead of CT, to plan SBRT.
Human immunodeficiency virus-associated Burkitt lymphoma in a Japanese patient with early submandibular swelling: a case report
Authors: Komatsu Noriko , Kawase-Koga Yoko , Mori Yoshiyuki , Kamikubo Yasuhiko , Kurokawa Mineo , Takato Tsuyoshi
Published: December 2013

Background

Patients infected with the human immunodeficiency virus (HIV) are at risk of developing malignancies and have an increased susceptibility to infection. HIV-associated Burkitt lymphoma (BL) is relatively rare in developed countries, but remains prevalent in developing counties and is sometimes compounded by the fact that patients may be unaware that they are HIV-positive.

Case presentation

A 37-year-old Japanese man was referred to our department for diagnosis and management of submandibular swelling. He was unaware that he was HIV-positive at the initial visit. Here, we describe our diagnostic approach, in which we used hematological and immunological investigations, biopsy, fluorescence-activated cell sorting and fluorescence in situ hybridization to confirm the diagnosis of HIV-associated BL. The patient has no risk factors for HIV infection, and the source of infection remains unclear.

Conclusions

In this case, submandibular swelling was the first clinical sign of pathology and the patient’s HIV-positive status only became evident later. It is highly likely that BL was triggered by HIV infection.
Does PRRT with standard activities of 177Lu-octreotate really achieve relevant somatostatin receptor saturation in target tumor lesions?: insights from intra-therapeutic receptor imaging in patients with metastatic gastroenteropancreatic neuroendocrine tumors
Authors: Sabet Amir , Nagarajah James , Dogan Ahmet Semih , Biersack Hans-Jürgen , Sabet Amin , Guhlke Stefan , Ezziddin Samer
Published: December 2013

Background

Peptide receptor radionuclide therapy (PRRT) with 177Lu-[DOTA0,Tyr3]octreotate (177Lu-octreotate) is generally performed using a fixed activity of 7.4 GBq (200 mCi) per course bound to 180 to 300 μg of the peptide. While this single activity may lead to suboptimal radiation doses in neuroendocrine tumors (NET) with advanced or bulky disease, dose escalation has been withheld due to concerns on potential tumor somatostatin receptor saturation with reduced efficacy of the added activity. In vivo saturation effects during standard-dose PRRT based on quantification of pre- and intra-therapeutic 68Ga-DOTATOC positron emission tomography (PET) imaging might guide potential dose escalation.

Methods

Five patients with metastatic NET of the pancreas underwent 68Ga-DOTATOC PET/CT before and directly after standard-dose PRRT with 177Lu-octreotate. In each patient, four target tumor lesions, normal liver parenchyma, and the spleen were evaluated and the ratios of SUVmax of the target lesions to liver (SUVT/L) and spleen (SUVT/S) were calculated; paired Student's t test was performed with p < 0.05 for pre-/intra-PRRT comparisons.

Results

The mean intra-therapeutic tumor SUVmax showed no significant change (per-lesion paired t test) compared to pretreatment values (-9.1%, p = 0.226). In contrast, the SUVmax of the normal liver parenchyma and spleen were significantly lower directly after infusion of 7.4 GBq 177Lu-octreotate. Consequently, SUVT/L and SUVT/S increased significantly from pretreatment to intra-therapeutic examination: SUVT/L (p < 0.001) from 2.8 ± 1.3 (1.3 to 5.8) to 4.7 ± 3.0 (2.1 to 12.7) and SUVT/S (p < 0.001) from 1.2 ± 0.7 (0.4 to 3.0) to 3.5 ± 1.5 (1.6 to 7.9).

Conclusions

This small retrospective study provides preliminary evidence for the absence of relevant in vivo saturation of somatostatin receptor subtype 2 (sst2) in tumor lesions during PRRT with standard activities of 177Lu-octreotate in contrast to normal tissue (liver, spleen) showing limited receptor capacity. After being confirmed by larger series, this observation will have significant implications for PRRT: (1) Higher activities of 177Lu-octreotate might be considered feasible in patients with high tumor disease burden or clinical need for remission, and (2) striving to reduce the amount of peptide used in standard preparations of 177Lu-octreotate appears futile.
Collagen Nanofiber-templated Silver Nanowires on Graphene Nanosheets for a Nonenzymatic Amperometric Biosensor of Hydrogen Peroxide
Authors: Wang Li , Ni Pengjuan , Wei Gang , Wang Jiku , Li Zhuang
Published: December 2013

A nonenzymatic amperometric biosensor for sensitive detection of H2O2 has been successfully fabricated by using silver nanowires (AgNWs) supported on graphene nanosheets (GNs). The AgNWs were created through using a collagen-mediated biomimetic synthesis of silver nanoparticles on collagen nanofibers (Col-NFs). The electrode modified with the synthesized GN–AgNW nanohybrids displayed high electrocatalytic activity to the reduction of H2O2.
Fabrication of ICG Dye-containing Particles by Growth of Polymer/Salt Aggregates and Measurement of Photoacoustic Signals
Authors: Fukasawa Tomonori , Hashimoto Maya , Nagamine Shinsuke , Aoki Hiroyuki , Shinto Hiroyuki , Ito Shinzaburo , Ohshima Masahiro
Published: December 2013

We fabricated salt–crosslinked polymer particles as contrast agents for photoacoustic imaging using poly(allylamine hydrochloride) (PAH), a phosphate salt (NaH2PO4 or Na2HPO4), and an organic dye of indocyanine green (ICG). The surfaces of the polymer particles were coated with silica nanoparticles, resulting in improvement of their dispersion stability in a physiological saline solution. The suspensions of all prepared particles gave sufficiently large photoacoustic signals.
Doping Effect in Three-dimensional Donor–Acceptor Magnet: Percolated Magnetic Pathways Dominated by Local Electron Transfers
Authors: Fukunaga Hiroki , Kosaka Wataru , Miyasaka Hitoshi
Published: December 2013

In an electron-donor (D)–electron-acceptor (A) three-dimensional assembly series with a D2A formulation, their magnetic properties were tuned by doping another D unit with a stronger electron-donating ability capable of reducing A− to A2−. The magnetic-phase-transition temperature (Tc) of doped compounds nonlinearly decreases with increasing doping rate.
Fabrication of α-Bi2O3 Microrods by Solvothermal Method and Their Photocatalytic Performance
Authors: Wang Jian , Liu Jun , Wang Bingbing , Zhu LinLin , Hu JieHui , Xu Hongbo
Published: December 2013

An ethanol–water (CH3CH2OH–H2O) system was designed to synthesize α-Bi2O3 microrods by a mild and one-step solvothermal method in the presence of surfactant dodecylamine (C12H27N). X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy (DRS) were employed to characterize the structure and morphology of the samples. The photocatalytic activity of α-Bi2O3 microrods was evaluated by the degradation of Methyl Orange (MO) under visible-light irradiation (λ > 420 nm), which was up to 90% within 4 h.
Sales Taxes and Internet Commerce
Authors: Einav Liran , Knoepfle Dan , Levin Jonathan , Sundaresan Neel
Published: December 2013

We estimate the sensitivity of Internet retail purchasing to sales taxes using eBay data. Our first approach exploits the fact that a seller's location—and therefore the applicable tax rate—is revealed only after a buyer has expressed interest in an item. We document how adverse tax “surprises” reduce the likelihood of purchase and shift subsequent purchases toward out-of-state sellers. We then use more aggregated data to estimate that every one percentage point increase in a state's sales tax increases online purchases by state residents by almost 2 percent, while decreasing their online purchases from state retailers by 3–4 percent. (JEL H71, L81, L86)
Violence and Risk Preference: Experimental Evidence from Afghanistan
Authors: Callen Michael , Isaqzadeh Mohammad , Long James D. , Sprenger Charles
Published: December 2013

We investigate the relationship between violence and economic risk preferences in Afghanistan combining: (i) a two-part experimental procedure identifying risk preferences, violations of Expected Utility, and specific preferences for certainty; (ii) controlled recollection of fear based on established methods from psychology; and (iii) administrative violence data from precisely geocoded military records. We document a specific preference for certainty in violation of Expected Utility. The preference for certainty, which we term a Certainty Premium, is exacerbated by the combination of violent exposure and controlled fearful recollections. The results have implications for risk taking and are potentially actionable for policymakers and marketers. (JEL A12, C91, D12, D74, D81, O12, O17)
Consumption Risk-Sharing in Social Networks
Authors: Ambrus Attila , Mobius Markus , Szeidl Adam
Published: December 2013

We develop a model in which connections between individuals serve as social collateral to enforce informal insurance payments. We show that: (i) The degree of insurance is governed by the expansiveness of the network, measured with the per capita number of connections that groups have with the rest of the community. “Two-dimensional” networks—like real-world networks in Peruvian villages—are sufficiently expansive to allow very good risk-sharing. (ii) In second-best arrangements, insurance is local: agents fully share shocks within, but imperfectly between endogenously emerging risk-sharing groups. We also discuss how endogenous social collateral affects our results. (JEL D85, G22, O15, O17, Z13)
Estimating a Structural Model of Herd Behavior in Financial Markets
Authors: Cipriani Marco , Guarino Antonio
Published: December 2013

We develop a new methodology to estimate herd behavior in financial markets. We build a model of informational herding that can be estimated with financial transaction data. In the model, rational herding arises because of information-event uncertainty. We estimate the model using data on a NYSE stock (Ashland Inc.) during 1995. Herding occurs often and is particularly pervasive on some days. On average, the proportion of herd buyers is 2 percent; that of herd sellers is 4 percent. Herding also causes important informational inefficiencies in the market, amounting, on average, to 4 percent of the asset's expected value. (JEL C58, D82, D83, G12, G14)
Worktime Regulations and Spousal Labor Supply
Authors: Goux Dominique , Maurin Eric , Petrongolo Barbara
Published: December 2013

We study interdependencies in spousal labor supply by exploiting the design of the French workweek reduction, which introduced exogenous variation in one's spouse's labor supply, at constant earnings. Treated employees work on average two hours less per week. Husbands of treated women respond by reducing their labor supply by about half an hour, consistent with substantial leisure complementarity, and specifically cut the nonusual component of their workweek, leaving usual hours unchanged. Women's response to their husband's treatment is instead weak and rarely statistically significant, possibly due to heavier constraints in the organization of their workweek. (JEL J16, J22, K31)
Risk Shocks
Authors: Christiano Lawrence J. , Motto Roberto , Rostagno Massimo
Published: December 2013

We augment a standard monetary dynamic general equilibrium model to include a Bernanke-Gertler-Gilchrist financial accelerator mechanism. We fit the model to US data, allowing the volatility of cross-sectional idiosyncratic uncertainty to fluctuate over time. We refer to this measure of volatility as risk. We find that fluctuations in risk are the most important shock driving the business cycle. (JEL D81, D82, E32, E44, L26)
One Swallow Doesn't Make a Summer: New Evidence on Anchoring Effects
Authors: Maniadis Zacharias , Tufano Fabio , List John A.
Published: December 2013

Some researchers have argued that anchoring in economic valuations casts doubt on the assumption of consistent and stable preferences. We present new evidence that explores the strength of certain anchoring results. We then present a theoretical framework that provides insights into why we should be cautious of initial empirical findings in general. The model importantly highlights that the rate of false positives depends not only on the observed significance level, but also on statistical power, research priors, and the number of scholars exploring the question. Importantly, a few independent replications dramatically increase the chances that the original finding is true. (JEL D12, C91)
Partnerships versus Corporations: Moral Hazard, Sorting, and Ownership Structure
Authors: Kaya Ayça , Vereshchagina Galina
Published: December 2013

Team production takes advantage of technological complementarities but comes with the cost of free-ridership. When workers differ in skills, the choice of sorting pattern may be associated with a nontrivial trade-off between exploiting the technological complementarities and minimizing the cost of free-ridership. This paper demonstrates that whether such a trade-off arises depends (i) on how the power of incentives required for effort provision varies with workers’ types, and (ii) on whether the workers are organized for production in partnerships or in corporations. These results have implications for how production is organized in different industries—in partnerships or in corporations. (JEL D21, D82, G32, M12, M54)
Social Ideology and Taxes in a Differentiated Candidates Framework
Authors: Krasa Stefan , Polborn Mattias
Published: December 2013

Many observers argue that political polarization, particularly on social and cultural issues, has increased in the United States. How does this influence the political competition on economic issues? We analyze this question using a framework in which two officemotivated candidates differ in their fixed ideological position and choose a level of government spending to maximize their vote share. In equilibrium, candidates cater to a set of swing voters who contain socially conservative and economically-liberal voters, as well as socially-liberal and economically-conservative voters. We analyze how voters’ cultural preferences and candidates’ cultural positions influence equilibrium economic positions. (JEL D72, E62, H50, Z13)
Estimating Models with Dispersed Information
Authors: Melosi Leonardo
Published: December 2013

We conduct likelihood evaluation of a DSGE model in which firms have imperfect common knowledge. Imperfect common knowledge is found to be more successful than price stickiness à la Calvo to account for the highly persistent effects of nominal shocks on output and inflation. Our likelihood analysis suggests that firms pay little attention to aggregate nominal conditions. This paper shows that such allocation of attention is plausible because it is optimal for firms with a reasonably small size of information frictions and a size of idiosyncratic uncertainty that is in line with the micro evidence on price changes. (JEL C51, D83, E13, E23, E31)
Wage Rigidity and Disinflation in Emerging Countries
Authors: Messina Julián , Sanz-de-Galdeano Anna
Published: December 2013

This paper examines the consequences of rapid disinflation for downward wage rigidities in two emerging countries, Brazil and Uruguay. Although wage rigidities are altered by disinflation, in neither of the two countries does price stability eliminate frictions in wage-setting mechanisms. In a context of individual wage negotiations and weak unions, disinflation in Uruguay puts an end to its history of indexation, but strong resistance to nominal wage cuts emerges. In strongly unionized Brazil, wage indexation is highly persistent, but the introduction of inflation targeting by the Central Bank in 1999 moves the focal point of wage negotiations to expected inflation. (JEL E31, E52, J31, J51, O11, O15, O23)
Can Tax Rebates Stimulate Consumption Spending in a Life-Cycle Model?
Authors: Huntley Jonathan , Michelangeli Valentina
Published: December 2013

We build a life-cycle model with earnings risk, liquidity constraints, and portfolio choice over tax-deferred and taxable assets to evaluate how household consumption changes in response to shocks to transitory anticipated income, such as the 2001 income tax rebate. Households optimally invest in tax-deferred assets, which are encumbered by withdrawal penalties, and exchange taxable precautionary savings for higher after-tax returns. The model predicts a higher marginal propensity to consume out of a rebate than is predicted by a standard frictionless life-cycle model. Liquidity-constrained households—with few financial assets or portfolios expensive to reallocate—consume a higher fraction of the rebates. (JEL D91, E21, G11, H24)
A Theory of Countercyclical Government Multiplier
Authors: Michaillat Pascal
Published: December 2013

I develop a New Keynesian model in which a type of government multiplier doubles when unemployment rises from 5 percent to 8 percent. This multiplier indicates the additional number of workers employed when one worker is hired in the public sector. Graphically, in equilibrium, an upward-sloping quasi-labor supply intersects a downward-sloping labor demand in a (employment, labor market tightness) plane. Increasing public employment stimulates labor demand, which increases tightness and therefore crowds out private employment. Critically, the quasi-labor supply is convex. Hence, when labor demand is depressed and unemployment is high, the increase in tightness and resulting crowding-out are small. (JEL E12, E24, E32, E62)
Credit Constraints and Self-Fulfilling Business Cycles
Authors: Liu Zheng , Wang Pengfei
Published: December 2013

We argue that credit constraints not only amplify fundamental shocks, they can also lead to self-fulfilling business cycles. We study a model with heterogeneous firms, in which imperfect contract enforcement implies that productive firms face binding credit constraints, with the borrowing capacity limited by expected equity value. A drop in equity value tightens credit constraints and reallocates resources from productive to unproductive firms. Such reallocation reduces aggregate productivity, further depresses equity value, generating a financial multiplier. Aggregate dynamics are isomorphic to those in a representative-agent economy with increasing returns. For sufficiently tight credit constraints, the model generates self-fulfilling business cycles. (JEL E13, E32, E44)
Some Evidence on the Importance of Sticky Wages
Authors: Barattieri Alessandro , Basu Susanto , Gottschalk Peter
Published: December 2013

We present evidence on the frequency of nominal wage adjustment using SIPP data adjusted for measurement error. The SIPP is a representative sample of the US population. Our main results are: (i) The average quarterly probability of a nominal wage change is between 21.1 and 26.6 percent, depending on the assumptions used. (ii) Wage changes are much more likely when workers change jobs. (iii) The frequency of wage adjustment does not display significant seasonal patterns. (iv) The hazard of a nominal wage change first increases and then decreases, with a peak at 12 months. (JEL E24, E32, E52, J31)
Fluoride Exposure, Caregiver Education, and Decayed, Missing, Filled Teeth (dmft) in 2-5 year-old English or Spanish Speaking Children
Authors: Uceda Paola R. , Sanzone Lauren A. , Phillips Ceib L. , Roberts Michael W.
Published: December 2013

Dental caries is a multifactorial disease that includes behavioral and cultural components. The study’s purpose was to determine the caries experienced (as measured by dmft) in a group of 2-5 y/o children, assess their family and home environment including consumption of fluoridated drinking water, use of a fluoride containing dentifrice, and level of caregiver formal education.

Parents of children referred for dental treatment under general anesthesia and who either spoke and read English or Spanish were recruited and consent obtained. Selected information on the family home, parental education and selected fluoride contact data was obtained. An oral clinical examination of the child assisted by intraoral radiographs was completed and the number of decayed, missing, filled primary teeth (dmft) recorded for each child. Bitewings were obtained if posterior or anterior teeth contacts were closed but only periapical radiographs were obtained if contacts were open. Children of English speaking caregivers had statistically more dmft after controlling for the effect of the child’s age and years of parental education (p=0.04). English speaking families had lived in their current home longer and the parent had more formal education than did the Spanish speaking parent. When available, the English children drank municipal tap water more often than did the Spanish children. Spanish speaking parents often chose bottled drinking water. No difference between the two groups was found in the use of tap water for cooking or the use of fluoridated dentifrice.

In conclusion, increased parent education, language spoken by the parents and time living in the current home were not associated with lower dmft. Drinking fluoridated drinking water did not affect the dmft. However, using fluoridated water when available to cook and using fluoride containing dentifrice by both groups may have been mutually beneficial.
Growth and Reproductive Phenology of Welwitschia Mirabilis Hook. F.
Authors: Di Salvatore M. , Carafa A. M. , Carratù G.
Published: December 2013

Reproductive phenology, reproductive traits and the pre emergent reproductive success (PERS) of Welwitschia mirabilis were studied in plants growing in the Botanical Garden of Portici. The leaves grow throughout the year and growth is positively correlated to temperature and day length; at flowering, the growth rate slows down. The plants have a reproductive cycle lasting 9-10 months; male plants form more branches and strobili than females, female strobili are larger than male ones. Both male and female plants produce cones that differ in the color of the covering bracts. Plants produce a lot of seeds, but most of them are empty; therefore the seed/ovule ratio is low. Filled and empty seeds are morphologically similar; filled seeds have high vitality that is maintained for several years. As probable causes of the low seed/ovule ratio, both pollination and embryo abortion are taken into account; our observations lead us to believe that the embryo abortion hypothesis is more accurate. However, since each plant may produce a discrete number of cones and filled seeds are highly viable, ultimately Welwitschia appears to be a rather efficient plant in terms of pre emergent reproductive success.
Modeling of the buckstay system of membrane-walls in watertube boiler construction
Authors: Nagiar Hasan , Maneski Tasko , Milosevic-Mitic Vesna , Gacesa Branka , Andjelic Nina
Published: December 2013

Membrane walls are very important structural parts of water-tube boiler
construction. Based on their specific geometry, one special type of finite
element was defined to help model the global boiler construction. That is the
element of reduced orthotropic plate with two thicknesses and two elasticity
matrixes, for membrane and bending load separately. A global model of the
boiler construction showed that the high value of stress is concentrated in
plates of the buckstay system in boiler corners. Validation of the new finite
element was done on the local model of the part of membrane wall and
buckstay. A very precise model of tubes and flanges was compared to the model
formed on the element of a reduced orthotropic plate. Pressure and thermal
loads were discussed. Obtained results indicated that the defined finite
element was quite favorable in the design and reconstruction of the boiler
substructures such as a buckstay system.
Fracture mechanics analysis of damaged turbine rotor discs using finite element method
Authors: Vasovic Ivana , Maksimovic Stevan , Stamenkovic Dragi , Stupar Slobodan , Maksimovic Mirko , Bakic Gordana
Published: December 2013

This paper presents evaluation fracture mechanics parameters in low pressure
turbine components. Critical locations such as keyway and dovetail area are
experiencing stress concentration leading to crack initiation. Stress
intensity factors were evaluated using the J-Integral approach available
within ANSYS software code. The finite element method allowed the prediction
of the point of crack initiation and the crack propagation using the
orientations of the maximum principal stresses. Special attention in this
investigation is focused to develop analytic expressions for stress intensity
factors at critical location of low pres-sure steam turbine disc.
The initial analysis of the river Ibar temperature downstream of the lake Gazivode
Authors: Kalaba Dragan , Ivanovic Ivana , Cikara Dejan , Milentijevic Gordana
Published: December 2013

As a result of a very limited number of geometric and other input data, the
temperature modeling of the river Ibar downstream of the lake Gazivode was
started by analyzing one river reach between Pridvorica, secondary dam in the
system Gazivode, and the city Kosovska Mitrovica. River reach was selected so
that the numerical results can be compared with available measured
temperature data. Water quality component of HEC-RAS one-dimensional
hydraulic river model was used for temperature calculations.
Remaining life assessment of a high pressure turbine casing in creep and low cycle service regime
Authors: Bakic Gordana , Sijacki-Zeravcic Vera , Djukic Milos , Rajicic Bratislav , Tasic Marko
Published: December 2013

Thick walled components such as high pressure (HP) steam turbine casings
operating under high parameter conditions are subjected to a complex stress
state. As a result of that stress state, some parts of HP turbine casing
undergo to the creep fatigue caused by the combination of thermal fatigue
resulted from repeated start/stop operation and the creep which occurs during
long-term operation at high temperature and high-pressure. It is well known
that domestic thermal power plants have been in use over 100000 h which means
that significant cost is required not only for maintenance, but often for
renewal of equipment. Based on comprehensive investigation, the results of
residual life assessment of one high pressure steam turbine casing, which
belongs to the older turbine generation, taking into account simultaneous
action of thermal fatigue and creep, are presented in this paper. Also, the
critical flaw crack size of HP turbine casing is determined because this
parameter has a strong influence on casing integrity and residual life. The
results of residual life assessment provide not only a basis for further
maintenance, but also estimated time for reparation or renewal.
Numerical analysis of temperature field during hardfacing process and comparison with experimental results
Authors: Lazic Vukic , Ivanovic Ivana , Sedmak Aleksandar , Rudolf Rebeka , Lazic Mirjana , Radakovic Zoran
Published: December 2013

The three-dimensional transient nonlinear thermal analysis of the hard facing
process is performed by using the finite element method. The simulations
were executed on the open source Salome platform using the open source
finite element solver Code_Aster. The Gaussian double ellipsoid was selected
in order to enable greater possibilities for the calculation of the moving
heat source. The numerical results were compared with available experimental
results.
Dynamic temperature field in the ferromagnetic plate induced by moving high frequency inductor
Authors: Milosevic-Mitic Vesna , Maneski Tasko , Andjelic Nina , Milovic Ljubica , Petrovic Ana , Gacesa Branka
Published: December 2013

The subject of the paper is the temperature distribution in the thin metallic
ferromagnetic plate influenced by moving linear high frequency induction
heater. As a result of high frequency electromagnetic field, conducting
currents appear in the part of the plate. Distribution of the eddy-current
power across the plate thickness is obtained by use of complex analysis. The
influences of the heater frequency, magnetic field intensity and plate
thickness on the heat power density were discussed. By treating this power as
a moving heat source, differential equations governing distribution of the
temperature field are formulated. Temperature across the plate thickness is
assumed to be in linear form. Differential equations are analytically solved
by using integral-transform technique, Fourier finite-sine and finite-cosine
transform and Laplace transform. The influence of the heater velocity to the
plate temperature is presented on numerical examples based on theoretically
obtained results.